technical rubber products

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Technical Rubber Products The key to performance

RUBRIK

MARKETS & BRANDSWith six strong brands and more than 200 individual products, LANXESS is one of the biggest players on the global market for technical rubber The right material for every application – Properties and uses of selected rubber grades THE HISTORY OF RUBBER Whether taken from the milk of the “Havea brasiliensis” plant or synthesized chemically, rubber is one of the elementary materials of modern technology How Charles Goodyear came upon vulcanization How the “Havea brasiliensis” moved from Brazil to south-east Asia

LANXESS The young company with a long tradition supplies cus-tomers all over the world with a broad range of synthetic rubber products and chemicals The varied history of Building K 10

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RUBBER CHEMICALSWith a global market share of around 20 percent, LANXESS is one of the top suppliers of chemicals to the rubber industry

THERBAN®

Wi u How the NBR rubber Perbunan® was turned into the high-performance rubber Therban®

LEvApREN®

Thanks to its versatility, the ethylene-vinyl acetate rubber Levapren® serves as a material for numerous applications Adhesives and films based on Levamelt®

pOLYMER TESTINGWhich tests can be conducted in LANXESS’s test labora-tory in Leverkusen

ALL-ROUNDERS Sealing, damping, transporting – Technical rubber prod-ucts perform vital services in numerous variants

SEALING Whether in buildings, cars, pumps or machines or on oil rigs, seals made of resistant rubber can cope with nearly all stressful conditions What tasks rubber components have to play in oil production

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Contents

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4 Markets and rubber brands

20 The LANXESS group

38 Make or break for polymers

26 Therban® – A suc-cess story

32 Levapren® - A ver-satile material10 The history of

rubber

INHALT

QUALITY & SAFETYProfessional management ensures customer satisfaction through quality, workplace safety and non-hazardous products ARTwORK MADE OF RUBBER For the artist Eva Ohlow, rubber is the starting material for deeply meaningful works of art. She has drawn inspi-ration from her journeys to Africa

MASTHEAD / pICTURE CREDITS

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DAMpINGWhenever it oscillates, jerks, judders or vibrates, damp-ers and springs made of rubber quieten things down

TRANSpORTING Belts, straps, hoses and cables – getting ores, letters, liquids, energy and much more besides on the move with the help of elastomers

DRIvE BELTS Whenever power has to be transmitted, belts of various shapes and sizes made of customized material combina-tions give the necessary impetus

HOSESWhether for the fire department, cars, oil platforms or air conditioning systems, there is always a hose to fit the bill Heatable hoses for clean waste gases

INNOvATIONS High-quality adhesives, fire-retardant cable sheathing, light-bonding film and new combinations of materials are only some of the innovations from the LANXESS laboratory

TIRES Without air-filled tires made of rubber, the mobility and logistics of today would be unthinkable – visions of the past and of the future Green tires – on behalf of the environment

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74 Innovations are the key to growth

76 The road to green tires

88 Quality serving the customer

54 Dampers keep it quiet 46 Seals for dramatic

events 62 Rubber gets things moving

Artwork made of rubber92

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VERSATILE

Ethylene-propylene-diene rubber – EPDMEXAMPLE: Buna® EP

HEAT-RESISTANT

Ethylene-vinyl acetaterubber – EVMEXAMPLE: Levapren®

GREASE-RESISTANT

Nitrile-butadiene rubber – NBREXAMPLE: Perbunan®

MARKETS & BRANDS

Global market for elastomers

RESILIENT

Chloroprene rubber – CREXAMPLE: Baypren®

ROBUST

Hydrogenated acrylonitrile- butadiene rubber – HNBREXAMPLE: Therban®

Products that contain synthetic rubber in one of its many guises perform a whole variety of functions. Most of the time, they work behind the scenes – un-der the hood or in the wheel housing of vehicles, in window frames or as a transparent layer in films, as base material for adhesives and in electric cable sheathings, as bearings in freeway bridges, in heavily used floor covering and conveyor belts, in founda-tions for skyscrapers and on oil platforms. They seal stadium roofs, protect vehicles from vibrations from both the road and their own engines and are used for transportation in the form of hoses and belts.Chemical companies such as LANXESS supply their customers in the rubber processing industry with a wide variety of elastomers with various properties that

fulfill specific roles even under extremely tough condi-tions. They withstand heat and cold without losing their elasticity, they cope with aggressive substances such as gasoline, oil and brake fluids, and they are not broken down by either UV radiation or gases such as ozone and oxygen. They endure extremely powerful impacts and vibrations and are even a match for the coarse, sharp-edged excavation waste found in mining.Other rubber grades are combined with metals or plastics to make “bombproof” combinations of ma-terials or wafer-thin films that adhere only lightly to a substrate and can be removed from it easily without causing damage.

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synthetic rubbers for the tire industry and for numerous technical applications. At the same time, the company has extended and modernized its facilities in Canada, France and Germany to reinforce its claim to be the lead-ing supplier of premium products.LANXESS’s Technical Rubber Products (TRP) business unit is part of the Performance Polymers segment, which since October 1, 2007 has also included the Butyl Rubber, Performance Butadiene Rubbers and Semi-Crystalline Products business units. The rubber grades processed outside the tire industry cover the Therban®, Levapren®, Perbunan®, Krynac®, Baypren® and Buna® EP product families/brands. These comprise the follow-ing elastomers: ethylene-propylene-diene rubber (EPDM: Buna® EP), chlorobutadiene rubber (CR: Baypren®), ac-rylonitrile-butadiene rubber (NBR: Krynac®, Perbunan®, Baymod® N), hydrogenated acrylonitrile-butadiene rub-ber (HNBR: Therban®) and ethylene-vinyl acetate rubber (EVM): Levapren®, Levamelt®, Baymod® L). The six rubber brands from LANXESS provide users with over 200 individual products. Many of these are geared to particular areas of application and adapted to the specific needs of each customer. With these prod-ucts and rubber chemicals, LANXESS achieves sales of more than EUR 500 million each year and serves over 600 customers.Although the automotive industry is the largest con-sumer of rubber products made from temperature- and media-resistant specialties from LANXESS, it accounts

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Committed to growthThe diversity of rubber’s properties and varieties and its still far from exhausted application potential have ensured sustained growth in sales on international mar-kets for many years. In particular, economically dynamic markets and countries in Asia such as China and India along with Russia, Eastern Europe and Latin America are developing into strong customers in the rubber in-dustry and strong production locations. Including rubbers for the tire industry, manufacturers produced 13,596,000 metric tons of synthetic rubbers across the world in 2007, according to estimates by the International Rubber Study Group; consumption amounted to 13,197,000 metric tons. The largest consumer was Asia/Oceania with 6,369,000 metric tons (production: 5,994,000 metric tons), followed by North America (consumption: 2,140,000 metric tons, production: 2,790,000 metric tons) and the EU (consumption: 2,711,000 metric tons, production: 2,774,000 metric tons).

Close to customersAs one of the world’s leading suppliers of synthetic rubbers, LANXESS AG too is naturally boosting its posi-tion on key markets with high growth rates. Whether in China, India, Singapore or Brazil, the Leverkusen-based manufacturer of high-performance rubbers has recently strengthened its market position through ambitious investment in these dynamic markets. This is true of

The key consumer sectors*

MARKETS & BRANDS

46% automotive industry 15% footwear industry 15% mechanical engi-

neering4% electrical/elec-

tronics5% construction

industry12% other3% plastics industry

*of all manufacturers of technical rubbers

LANXESS generates sales of over EUR 500 million per year with technical rubbers and chemicals.

Elastomer “map”

MA

XIM

UM

HE

AT

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SIS

TAN

CE

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OIL SWELLING IN ASTM* OIL 3

MVQFMVQ

FKM

HNBRACM

NBRECO

CR

EPDM

IIR

BR

NR

SBR

EVM

160 120 80 40 0

40% VA 90% VA

AEM

*American Standard for Testing of Materials

for somewhat less than half of LANXESS revenues.Other application areas range from shoe soles and con-struction applications to high-performance electronics, with its rapid sales growth. Owing to strong demand and the many different applications such as the EVM product line with the LANXESS brands Levapren®, Levamelt® and Baymod® L, which are not just processed into films but also high-performance, heat-resistant rubber products and adhesives, LANXESS will be significantly expanding its EVM capacities in Dormagen, Germany up to 2009, investing EUR 10 million.

High-growth product familiesThe hydrogenated acrylonitrile rubber product line from the Therban® family is also enjoying above-average growth rates. Therban® offers excellent aging resistance even when subjected to extreme mechanical-dynamic loads, in aggressive media and across a wide tem-perature range. LANXESS currently offers 25 different grades of this rubber, including six of the fast growing Therban® AT grades. Therban® AT boasts particularly good flowability, which enables it to be widely used in a large number of products that have become more cost-effective due to the polymer’s higher filler tolerance, and can be manufactured even more economically using injection molding or extrusion thanks to the improved flowability. New products with high ACN content exhibit impressive resistance to fuels such as biodiesel and ethanol and are ideal for hoses and cables in vehicles due to their heat resistance.

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1 High-performance rubbers (1 percent of

sales volume, 10 percent of sales revenue): FKM, HNBR, MVQ, PMVQ, FMVQ, (E)CO, EVM, AEM, ACM.

2 Specialty rubbers (17 percent of sales

volume, approx. 30 per-cent of sales revenue): CR, NBR, EP(D)M, (X)IIR.

3 Multi-purpose rub-bers (82 percent of

sales volume, 60 percent of sales revenue): NR, BR, SBR.

Nitrile rubbers (NBR) from the Perbunan®, Baymod® N and Krynac® product families are also in heavy demand on the world’s markets. Thanks to their resistance to non-polar liquids – they do not swell up even in an oily environment – NBR rubbers are particularly well suited for seals and hoses, especially in mechanical engineer-ing. As one of the leading suppliers of NBR rubbers, LANXESS operates the world’s largest emulsion plant at La Wantzenau near Strasbourg in France, where it produces over 60 different grades of rubber that are exported throughout the world.Nanopren®, an emulsion styrene-butadiene rubber (ES-BR) with a precisely defined molecular structure and a chemically controllable surface functionality, also comes from La Wantzenau. Nanopren® is a versatile modifier and as such opens up new technological possibilities for the plastics and rubber industries.

Over 40 big playersEthylene-propylene-diene rubbers (EPDM) are particu-larly ideal for outdoor use because they are weather-resistant and do not become brittle or age prematurely even in UV light and fluctuating temperatures. EPDM rubbers such as Buna® EP are therefore ideal for use as sealing profiles, being used for example for the transparent roof structures of Olympic sports facilities in China.A further key market for EPDM rubber is the cable industry as it boasts excellent insulating performance and cost-efficiency.

Performance pyramid

VOLUME

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PR

ICE

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PRICE PER METRIC TON IN EUROS

MVQAEMEVMACMECO

HNBR

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10

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25

30

35

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45Rubbers according to price/performance index

PE

RF

OR

MA

NC

E IN

DE

X

LANXESS rubbers are in the premium class in the world of elastomers.

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NBREPDM

IIR

4 40 43 ∞

FKM

FMVQ

SBRNRBR

CR

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Technical rubber Rubber for the tire industry

Material Abbr. Properties Applications

Polyacrylate rubber ACM Temperature range: -25° to 170° C;good resistance to fuel oils; good aging and ozone resistance

Oil hoses, seals

Ethylene- acrylic elastomer

AEM Temperature range: -30° to 170° C; good weathering and ozone resistance; medium resistance to mineral oils

Oil hoses, seals, O-rings, shoes, cable sheathings

Chloroprene rubber CR Temperature range: -45° to 110° C; good mechanical properties; good ozone, weathering, chemical and aging resistance; medium oil and fuel resis-tance; high fire retardance

Cable sheathings, hoses, seals, window and construction profiles, drive belts, diving suits

Chlorosulfonated polyethylene

CSM Temperature range: -20° to 130° C; good ozone, aging, weathering and chemical resistance

Seals, membranes, films, molded products, roll covers, cable sheathings

Polybutadiene BR Temperature range: -80° to 90° C; ex-cellent strength; outstanding abrasion resistance; crack resistance

Car tires, conveyor belts, crash protection pads

Ethylene oxide epichlorohydrin rubber

ECO Temperature range -40° to 10° C;highly oil and fuel resistant; ozone resistant; satisfactory mechanical properties

Intermediate and outer layers for fuel hoses

Ethylene-propylene- diene rubber

EPDM Temperature range: -50° to 150° C; very good aging resistance, including for UV and ozone; resistant to dilute acids and non-mineral-oil-based brake fluids; not resistant to mineral oil products

Body seals in automotive engineering, roof and pond sheeting, membranes, seals, construction profiles, hoses, floor tiles, belts, con-veyor belts, roll covers

Ethylene-vinyl acetate rubber

EVM/EVA

Temperature range: -30° to 170° C;excellent heat resistance; goodelectrical properties

Hot product conveyor belts, flameretardant, halogenfree cable insulating materials, films, technical products of all kinds, sports shoe midsoles

Fluororubber FKM Temperature range: -25° to 200° C; very high resistance to ozone, oxygen, mineral oils, synthetic hydraulic fluids, fuels, many organic solvents; low gas permeability

Groove rings, lip rings, O-rings, wipers, preten- sioned elements and special seals

Hydrogenated nitrile rubber

HNBR Temperature range: -40° to 150° C; excellent physical properties, very good abrasion resistance; high resi-stance to ozone and hot air; good resi-stance to chemically aggressive oils

Heavyduty rubber products, e.g. for the oil industry and mechanical engineering such as seals, hoses, stators, belts for the automotive industry, cable insulation, special couplings

Butyl rubber IIR Temperature range: -40° to 140° C; good resistance to acids, hot water, glycol, high gas impermeability; high buffering capacity; ozoneresistant; moderate mechanical properties

Inner plies for tubeless tires, bladders for tire manufacture, roof sheeting, tunnel insulation, hot water hoses, bearing elements with excellent shock absorption, inner tubes for tires

Nitrile-butadienerubber,acrylonitrile-butadi-ene rubber

NBR Temperature range: -40° to 20° C;moderate ozone and weathering resis-tance; high resistance to oils, grease and hydrocarbons; favorable aging behavior; low abrasion

Seals, hoses for hydraulics and pneumatics; rubber gloves, elastic threads, blankets for print cylinders and rolls

Styrene-butadiene rubber

SBR Temperature range: 50° to 100° C; moderate abrasion resistance; good mechanical properties

Tread in car tires, technical rubber products (conveyor belts, seals, profiles); floorings; shoe soles and heels

MARKETS & BRANDS

Two process technologiesLANXESS is the only manufacturer in the world that produces EPDM using two different technologies – the slurry or suspension process and the solution process. These two processes enable LANXESS to offer a very wide range of EP rubber products, starting from grades with a very high molecular weight and high ethylene content that are manufactured in suspen-sion, all the way to amorphous grades with a medium molecular weight.In the EP rubber solution process, a catalyst in a hydrocarbon solvent in which the polymer is dis-solved during its formation is used to produce EPM or EPDM. If the required molecule size is reached, a chain termination is initiated and the solution is then washed before an antioxidant is added. In the case of oil-extended grades, an extender oil is added. The remaining hydrocarbons are removed from the rub-ber by using steam. The wet rubber crumbs are then drained, dried and packaged. In the suspension process, a soluble catalyst is used in a diluent in which the polymer is not soluble. This produces small rubber particles as a suspension in the reaction medium. As the reaction medium is of low vis-cosity, EPM and EPDM can be produced with a high molecular weight and high concentrations of solids.Following polymerization, water, antioxidants and ex-tender oils (for oil-extended EPDM grades) are added and the remaining hydrocarbons are removed from the suspension.In a similar way to the solution process, the resulting crumbs are then drained, dried and packaged.Both processes have their respective strengths. For example, EPDM special grades of extremely high vis-cosity can only be produced cost-effectively using the unique slurry technology. At the two production sites in Marl (Germany) and Orange (Texas, United States), whose capacity was increased to a total of 140,000 metric tons at the start of 2008, LANXESS currently produces over 40 different EPDM grades.To help meet the needs of thermoplastic processors, a pelleting plant for producing EPDM rubber recently went into operation in Marl.

Adhesives growth sectorThe Baypren® chloroprene rubber line is another key product family from LANXESS. With 100,000 metric tons per year, Baypren® is a major source of revenue for the Leverkusen-based group. The production plant in Dormagen, in which LANXESS invested around EUR 50 million in process technology and in expand-ing the capacity in 2007/2008, is the largest of its kind and the only one equipped with continuous polymerization technology. It therefore provides qua-lity that is unrivaled and, above all, constant. Baypren® continues to be regarded as an “all-round rubber”, but this only accounts for just over half of the sales

THE IDEAl MATERIAl FOR EVERy uSE

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volume, with 45 percent of the chloroprene rubber produced by LANXESS being used for premium adhesives, a segment enjoying annual growth rates in double figures, and the latex sector. The Baypren® family is thus increasingly helping reinforce and ex-pand LANXESS’s global lead in the high-performance rubber sector. With premium products, processes and services, LANXESS is looking to further enhance its role at the core of the chemical industry. This publication focuses primarily on products from the Technical Rubber Products business unit in the Performance Polymers segment and uses numerous examples to show the range and diversity of technical rubbers and their omnipresence in daily life.

Focusing on the dynamic markets of Asia, Eastern Europe, Russia and America – LANXESS is expanding.

Close to customersThroughout the world LANXESS has 44 sites in 21 countries, em-ploying a workforce of over 15,200.

Johannesburg, ZA

Burgettstown, USA

Chardon, USA

Pittsburgh, USA

Baytown, USA

Orange, USA

Bushy Park, USA

Porto Feliz, BR

Buenos Aires, AR

Sydney, Australia

Beijing, RC

Weifang, RC

Tokyo, J

Toyohashi, J

Seoul , ROK

Jhagadia, IND

Courbevoie, F

Cologne, D

Barcelona, E

Filago, I

Milan, I

Newbury, GB

Branston, GB

Mannheim, D

Sarnia, CDN

Birmingham, USA

Lerma, MEX

Mexico City, MEX

São Paulo, BR

Zárate, BR

Triunfo, BR

Cabo de Santo Agostinho, BR

Duque de Caxias, BR

Katol, IND

Rustenburg , ZA

Madurai, IND

Chennai, IND

Thane, IND

Singapore

Merebank, ZA

Isithebe, ZA

Newcastle, ZA

Tongling, RC

Shanghai, RC

Jinshan, RC

Wuxi, RC

Hong Kong, RC

Zwijndrecht, B

Leverkusen, D

Antwerp, B

Bratisláva, SK

Hamm-Uentrop, D

Bitterfeld, D

Brunsbüttel, D

Langenfeld, D

Marl, D

Krefeld-Uerdingen, D

Granges-Paccot, CH

Vilassar de Mar, E

Port Jérôme, F

São Leopoldo, BR

Dormagen, D

La Wantzenau, F

Qingdao, RC

RUBRIK

Die Havea brasili-ensis, so heißt der

aus Südamerika stammende Kaut-

schukbaum, bringt auf den Plantagen Südostasiens die höchsten Erträge.

There is hardly any other raw material that has had such an influence on the world as the sap of the Havea brasiliensis, the rubber tree.

There is probably no other natural product that has been so often the subject of myths, legends and tales of adventure as rubber latex – the milk, or sap, tapped from the trees and liana plants which grow in the rain forests immediately to the north and south of the equator. Hardly any other material has had such an influence on people and the way they live – being used for everything from clothing and toys to techni-cal products and cars. The industrial application of rubber has given us a faster pace of life and quite literally broadened the horizons of millions of people. It has been associated with fabulous riches and fame and, equally, with abject poverty and misery. The exploitation of the material that goes into our tires and a wide range of other products today is nothing new. It was practiced by the ancient Inca, Aztec and Maya peoples more than 2,000 years ago once they had learned how to tap the white, sticky milk from rubber trees and liana plants and stabilize the liquid extraction by drying and smoking it. From this, they were able to make balls, elastic bottles, waterproof clothing, shoes, cult objects – and even enema syringes.

The first reports to reach EuropeMyths surrounding this weird yet wonderful product and its “discovery” by Europeans have a long and colorful history. Christopher Columbus is said to have been amused to see Indians playing with a bounc-ing elastic ball. The first written reference to rubber, though, is attributed to a man by the name of Pietro Martire d’Anghiera. He called the sticky mass “gummi optima” and related how the Indios extracted and processed it. The word “caoutchouc” comes from the Indian name “ca-ou-tchouc” or “cau-hou-tchou” and refers to the

“weeping tree”. This term was adopted by the French-man Charles de la Condamine in 1735/1736 when he described how “latex” (adapted from the French word “lait”, meaning “milk”) was tapped from the rub-ber tree and made into a smoked mass. De la Condamine, a self-taught scientist who rose to become an aristocrat and member of the Paris Academy of Sciences, led two expeditions to South America, the first in 1735, with the aim of measuring the size and shape of the earth. From the Amazon region he sent the Academy a package containing

rubber together with a precise description of its origins, processing and use.

His other claim to fame is as the explorer who gave the Amazon

River its name on hearing about the war-faring women in the region.

Early basic research During the seven years de

la Condamine spent in South America he met François

Fresneau. Their acquaintance proved to be of great significance for the

future role of rubber in Europe and, indeed, the rest of the world. The trained engineer Fresneau was so captivated by de la Condamine’s enthusiasm for caoutchouc that he decided to undertake research in Guyana to find out more about the extraction, pro-cessing and use of natural rubber. De la Condamine published Fresneau’s scientific findings in France and, in doing so, laid the foundations for later indus-trial applications. In particular, Fresneau’s observation that caoutchouc could be dissolved in turpentine was to be of lasting importance. It meant that from now on the otherwise unstable latex milk could be shipped undamaged to Europe in the form of a turpentine so-lution. This was essential to the subsequent success of natural rubber. The word “rubber” – to describe the “tears” of the

The tears of ca-ou-tchouc

1492Long before America was discovered Incas, Mayas and Aztecs knew how to make use of rubber by drying and smoking it.

Around 1740 Charles de la Condamine coins the expression

“caoutchouc”. He played a major part in early scientific research into the sap or “milk” of Havea brasiliensis.

Milestones1400–1740

THE HISTORY OF RUBBER

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plant “Havea brasiliensis” – dates back to 1770 when the Englishman Joseph Priestley, best remembered for discovering oxygen, is said to have used a piece of caoutchouc to rub out pencil and charcoal markings.

The search for consistencyIt was not until the Industrial Revolution in the 19th century that inventors and entrepreneurs discovered just how versatile rubber was. And although Charles Nelson Goodyear from Newhaven, Connecticut, is officially regarded as the father of rubber thanks to his discovery of vulcanizing latex with sulfur, there were, in fact, inven-t ors before him who had pioneered the use of rubber in a variety of ways. At the India Rubber Manu factory in England, for example, Thomas Hancock had been making hoses for fire brigades, waterproof covers for horse-drawn coaches and rainwear for the passengers. And after the Scottish chemist Charles Macintosh had developed a double-layered fabric with a rubber lining, Hancock made him a partner in his company. Their raincoat, based on Macintosh’s “double texture”, was to take the world by storm.

At that time, though, rubber was still a problematic material to handle. High temperatures caused it to turn sticky and melt. Cold temperatures made it hard and brittle. These negative properties were particu-larly conspicuous in the extreme climate zones of the United States.

Inventor of vulcanizationGoodyear’s efforts to develop a non-sticky raw mate-rial from rubber as a way of remedying the problem of consistency came at the expense of his family’s welfare and ultimately cost him his life. Obsessed with his self-imposed mission and driven by financial pres-sures, Goodyear experimented with latex and various chemicals for seven years – until he finally achieved vulcanization in 1839 (see below). After further experiments and the laborious quest for funding, Goodyear eventually received patent no. 3633 for his “metallic gum elastic composition” in 1844. This was later known as vulcanization. In the patent specifica-tions Goodyear announced with some pride that, “I, Charles Goodyear from the City of New York, have

If ever anyone had a rubber obsession then it was Charles Nelson Goodyear. Over the centuries there has been a whole series of inventors, scientists and entrepreneurs, all of them fascinated by this elastic material, but no one else dedicated himself to the manufacture of rubber with the same manic obsession as Charles Goodyear. His passion for rubber not only put him behind bars because of debts he accumulated; it eventually cost him his life. When he died in 1860 at the age of 60 from the effects of his experiments with rubber and various poisonous chemicals, he bequeathed to the world one of its most precious materials. But, at the same time, he also left his family with 200,000 dollars worth of debts. His invention of vulcanizing rubber with sulfur may have brought him fame, but

certainly not fortune. Goodyear was born on December 29, 1800, in New Haven, Con-necticut. Following training in the Philadelphia trading company Roger & Brothers he worked in his father’s firm. In 1826, together with his father and brother, he founded an ironmongery and took out loans to expand the business. At the end of the 1820s, however, circumstances conspired against him. His creditors wanted their money back. This burden sub-jected the family to poverty and Charles Goodyear ended up in jail for not paying his debts. While in prison, debt-ridden Goodyear read about the growing importance of the rubber industry – and also about the problematic consistency of natural rubber. He learnt that in hot weather the substance melted to a sticky mass and in cold conditions turned stiff and brittle. There was the added complication of rubber’s extreme sensitivity to light, which rendered it unusable – and gave it an unpleasant smell. Determined to find a way of mak-ing rubber stable and durable, the impoverished Goodyear moved to New York. In the tiny kitchen of his humble abode he started ex-perimenting on his cooker with a frying pan and all kinds of chemi-cals, among them lead oxide and

turpentine oil. After yet another business failure, this time with the fabrication of rubber shoes and malfunctioning postal sacks, Goodyear made the acquaintance of Nathaniel Hayward in 1836. He was another “fanatic” who had experimented with caoutchouc gum. In his case, he had mixed it with sulfur and, in doing so, overcome the problem of sticky consistency. Goodyear persuaded the illiterate Hayward to register the process in his, Goodyear’s, name and apply for a patent. The rest is legend – or a tall tale. The story goes that Goodyear hid the rubber-sulfur compound from his wife by putting it in a hot oven – only to discover the material changed on being heated. The gum was now elastic and tensile, retained its flexibility even at low temperatures and remained dry in the warmth. These findings marked the invention of vulcani-zation. The plastic mass had been cured into elastic rubber gum.In 1842, following further ex-periments, Goodyear applied for a patent for the process he called “Metallic Gum Elastic Composi-tion”. It was granted in 1844. In his euphoria Goodyear set about creating an entire world of rubber. It included rainwear, gum boots and shoes – even rubber-top desks. He personally dressed

entirely in rubber-made clothes in public. This led his contempo-raries to put out the message: “If you see a man wearing a rubber coat, gum boots, a rubber hat and carrying in his pocket a rubber wallet with no money in it, then that person must be Charles Goodyear.” In the early 1850s, circumstances appeared to improve for a while. In 1850, Goodyear traveled to London to attend the World Ex-hibition. There, thanks to 30,000 dollar loans, he was able to pre-sent his wonderful world of rub-

ber to a wider public. In 1852, he finally won the longstanding and costly court proceedings against his adversary Horace Day. Not long after, Goodyear’s brother-in-law helped him out by investing 40,000 dollars in his Goodyear Metallic Rubber Company in Naugatuck, Connecticut. This was a firm making rubber footwear, in particular for gold-diggers in California – but it was a business without long-term prospects. In 1855, Goodyear borrowed a further 125,000 dollars to present his wares on a stand at the World Exhibition in Paris. After this he was ruined financially and again went to jail for non-pay-ment of debts. In 1858 he returned to the USA, a sick and broken man. To pay for the ship’s passage he had to pawn his wife’s jewelry. Just two years later he died. The rubber tire company named after him was not founded till some 38 years later – by Frank and Charles Seiberling, the sons of German immigrants. Today, it is one of the world’s leading tire manufacturers and serves as a fitting memorial to the man who fathered vulcanization.

PORTRAIT

The obsession of Charles Goodyear


1823In 1823 the Scottish chemist Charles Macin-tosh is granted a patent for his waterproof double textures.


Goodyear is said to have discov-ered vulcanization through ex-perimenting on his home cooker.

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RUBRIK

found a new and useful refining method for treating rubber products.”However, Goodyear’s processing technique proved to be easy to copy. The entrepreneur Horace Day succeeded in eliciting the inventor’s secret formula from a shoemaker who had not been paid for work done for Goodyear. Day then produced rubber along the lines of Goodyear’s “recipe”, using furnaces developed specifically for the purpose. It was not until costly litigation ended in a ruling against him that Day capitulated to Goodyear – at least for the time being – and agreed to take out a license.The Englishman Thomas Hancock was another rival involved in a legal dispute with Goodyear. Hancock had managed to get hold of a lump of rubber manu-factured by Goodyear and soon discovered that it was the result of being heated together with sulfur. So he developed his own hardening process and had it registered as a patent ten weeks ahead of Goodyear.It was not until March 23, 1852, that a court finally passed judgment in favor of Goodyear and awarded him patent no. 3833 – though this did not necessarily make life any easier. Determined to finance his own stand at the World Exhibition in Paris in 1855, the enthusiast plunged himself once again into mas-sive debt. When the inventor of vulcanization died in 1860 at the age of 60 from a life of deprivation and the effects of toxic fumes, he left his family debts amounting to 200,000 dollars.The rubber tire factory named after Goodyear was founded by the brothers Frank and Charles Seiberling in Akron, Ohio, in 1898, some 38 years after his death.While Goodyear had dreamt of manufacturing not

only clothing and footwear, but furniture as well – indeed a whole world of rubber – it was, in fact, technical products such as sealing and tubing, nautical equipment, household goods and water-proof, airtight travel aids that established themselves alongside raincoats and gum boots in the second half of the 19th century. Demand on a major scale was soon to come from another source entirely. It was the launch of the first motor carriage by Carl Benz in 1886 that heralded the age of the automobile. It brought with it the birth of the tire industry, which today is the largest user of rubber in both its natural and synthetic form.

Boom with bicycle and car tiresDemand for rubber increased fourfold in just a few decades after John Dunlop developed an air-filled bicycle tire with a protective outer tube of rubber and fabric (see page 22) and shortly before Carl Benz and Gottlieb Daimler presented their first motor vehicles to the world. These motors initially ran on iron-clad wooden wheels, but as soon as the emerging auto-mobile industry stepped up the use of hard rubber and pneumatic tires, the demand for natural rubber boomed. The first to capitalize on this were the “rubber barons” in Brazil. At the confluence of the Rio Negro and Rio Solimões – where the rivers meet to form the Amazon – the forest settlement of Manaus grew up within just a few years to become the center of the rubber trade in the second half of the 19th century. From here, hundreds of thousands of adventurers and have-nots set off into the jungles of the Amazon to join the


1850 Thomas Hancock wanted to claim the discovery of vulcanization for himself.

1857 Nautical articles made from rubber in a publica-tion by Thomas Hancock.

The English word rubber is said to have come from Thomas Priestley, who used the material to rub out writing.

Mixing and kneading, as in this illustration from the 19th century, are still essential activities in the manufacture of rubber.

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Knighthood for the seed smugglerAdventures, myths and legends sur-round the figure of Sir Henry Wickham. This restless globetrotter with his highly developed ego and sense of showmanship considerably raised his chances of a place in history through a series of books relating his travels. In 1920, eight years before his death, he received a knighthood – for his services as a smuggler! In 1876, commis-sioned by the India Office in London, Henry Wickham had smuggled 70,000 seeds from the rubber plant “Havea brasiliensis” out of the jungle, taken them down the river Rio Negro and transported them to England via Manaus and Pará (today known as Belén). This laid the foundations for the extensive cultivation of rubber in the plantations of south-east Asia.At the age of only twenty years, Wickham, who was born in Haverstock Hill on May 29, 1846, traveled to South America to hunt exotic birds in Nicaragua. Back in England, he sold their feathers for use as decoration in ladies’ hats. In 1869, he crossed the Atlantic for the second time and paddled in an Indio canoe through the interior of South America till he came to the rubber trees along the Rio Negro. After a year-long tour of the region, Wickham ended up in Manaus, where he boarded a steamship to Pará. There, he made friends with the resident British consul, James Drummond Hay. It was in no small part thanks to Hay’s

appendix in Wickham’s first book on his travels through Central and South America that Clements Markham from the India Office became interested in the prospect of cultivating the Havea brasiliensis plant in the British East Indies. In his writing Hay had made a point of referring to the huge profits the Brazilian rubber barons had been amassing from the latex collected by the Indios and forest hunters. Together with Joseph Hooker, head of the Royal Gardens at Kew near London, he devised a plan to grow the rubber seeds to the size of young plants in Kew Gardens and to subsequently cultivate them on plantations in Ceylon, Sumatra, Malaysia and what was then called the Dutch East Indies – today known as Indonesia. On the strength of his first-hand knowledge of Brazil, Wickham was commissioned in 1876 to ship some 70, 000 rubber seeds to England – a highly dangerous operation if one is to believe Wickham’s later reports. He claimed that the export of precious seeds was punishable with the death pen-alty in Brazil at that time. However, this did not prevent Wickham from undertaking the venture. He hired Indios from settlements along the River Tapajos to collect the seeds of the Havea brasiliensis plant and bring them to Manaus, where the chartered steamer “Amazonas” was lying in wait. According to Wickham’s accounts, he hid the seeds in stuffed crocodiles and so man-aged to smuggle them out of the country unnoticed. This, at least, is the version of events upon which Eduard von Borsody based his film in 1938. In fact, though, exporting the seeds was far less dramatic. They reached England wrapped in banana skins placed on top of each other in raffia baskets. There, gardeners at Kew Gardens managed to germinate some 2,000 seeds, which were then shipped out to Ceylon on the “Duke of Devonshire”. Although Wickham considered himself a leading expert on the subject of Havea brasiliensis, he was not allowed to accompany the

expedition – much to his disappointment. Instead, the seedlings were placed in the care of the chief gardener at Kew, William Chapman. Despite this supervision, so the story goes, only seven of these tender young plants survived the long voyage. But it may well be the number was much higher. Otherwise it is difficult to explain how, shortly after the arrival of the seedlings in Ceylon, a hundred plants could be shipped on to Singapore. Whatever the truth: the descendants of these seedlings provided the basis for what now amounts to some five million tons of latex from the rubber regions of south-east Asia, an area stretch-ing from 30 degrees north to 30 degrees south of the Equator. Once Wickham had recovered from the disappointment of such meager acknowl-edgement, he was off again on his next adventures. This time, he tried growing tobacco in Australia before joining the civil service in British Honduras (today Belize). Then, in 1895, he started trading in mother of pearl, sponges, tortoiseshell and rubber on the Conflict Islands to the east of New Guinea – only to fail yet again. Despite all these setbacks and financial problems Wickham never lost courage or faith in himself. He was able to spend the latter part of his life free from material need thanks to the support of wealthy rubber growers and rubber manufacturers. And, eventually, he was to receive ultimate recognition in the form of the knighthood.It is entirely due to the role of Sir Henry Wickham in breaking the Brazilian mo-nopoly on rubber and literally sowing the seeds of the subsequent rubber industry that such strides could be made – strides from which we continue to benefit.

PORTRAIT

Without the seeds taken out of Brazil by Wickham there might never have been today’s rubber plan-tations in south-east Asia. Right: The bill of entry issued by the port of Liver-pool on June 12, 1876, for the cargo of rubber seeds from the Amazon.Far right: Latex is still tapped in the same way as 1000 years ago.

Sir Henry Wickham spent his life roving from one project to the next. A few years before his death, he was knighted.


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Indios in collecting rubber. Thousands of them died in the process, others became very rich. The rubber metropolis of Manaus developed into a kind of City of Mahogany with five theaters and the famous gilded opera house Teatro Amazonas, which opened to a performance of Amilcare Ponchielli’s “La Gioconda” on December 31, 1896. Myths and legends surrounding this splendid building survive to this day. Whether the singer Enrico Caruso really did ever perform here is a matter of dispute. Thanks to its perfect acoustics, the Teatro still plays an important part in Brazil’s music world, even though it does not have a permanent ensemble. Harking back to those golden days is the railroad mu-seum in the middle of the “green hell” of the Amazon jungle. In the town of Porto Velho locomotives stand rusting on the remains of the railroad through the jungle along which natural rubber was once trans-ported. It is estimated that during the construction of this “railway of death” at least 6,000 people lost their lives between 1907 and 1912. Local myth puts the death toll much higher, quoting statistics of one dead person for every railway sleeper– the victim either of fever or poisoned Indio arrows. It took four attempts before the project, originally conceived in 1869 by the German engineer Franz Keller, could be realized. The first three attempts failed due to tropical storms, plagues of mosquitoes, hostile Indians, snakes and disease. The railroad connection owed its final completion – albeit at great sacrifice – to the Treaty of Petrópolis of November 17, 1903. This stipulated that Bolivia hand over the long-contested region of Acre to Brazil. In return, Bolivia insisted on the building of the railway.

However, hardly was the rail route finished when Brazil’s caoutchouc trade entered rapid decline. From 1930 onwards, only one train a day was needed to transport the meager volume of freight, and in 1972, the line was completely closed down. The re-instate-ment in 1981 of part of the route as a tourist attrac-tion was a brief success until 1999, when one of the bridges collapsed. At that point the locomotives ended up on a sleeper at the museum. Today, only a few of the 3,000 monthly tourists believe the locomo-tives, originally imported from Europe and the USA, will ever be made operational again.

Rubber collectors in the CongoLike the rubber barons of the Amazon, King Leopold II of Belgium also made a gigantic business out of ex-ploiting rubber. After his interest had been aroused by reports from Africa-explorer Henry Morton Stanley, he founded the “Association Africaine”. This soon became the “International Association of the Congo” – headed by him personally. Having created his own private colonial regime, Leopold went about systematically plundering the rubber reserves of this vast region of Central Africa. For the most part, the rubber came from the extensive growths of Liana landolphia ovariensis that could be anything up to 130 meters long. It must have been a terrible regime of violence. King Leopold’s governors press-ganged hundreds of thousands of natives, forcing them to work by throw-ing their families into prison. They penalized escapees and their relatives by whipping them and cutting off their hands and feet. The writer Joseph Conrad, who as the Polish captain Josef Teodor Korzeniovsky had sailed the length and breadth of the River Congo, related his experiences in a series of famous novels,


Around 1905Mola and Yoka, victims of atrocities committed in the Belgian Congo at the beginning of the 20th century.

1878King Leopold II of Belgium exploited the Congo as if it were his own private property.

Processing raw rubber in Africa in 1926.

Henry Morton Stanley, who encountered Dr. Livingstone in Africa, was one of the first to aid King Leopold.

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among them “Heart of Darkness”. It is estimated that more than ten million people lost their lives as a con-sequence of Leopold’s regime of terror in the Congo in the years up to 1907. (Adam Hochschild offers an impressive account of this period in his book “King Leopold’s Ghost”.)

Epochal theftThe hey-day of the rubber kings and barons who amassed fortunes for themselves by exploiting the wild rubber plant lasted only a few years. As early as 1876, the British adventurer Henry Wickham had been commissioned by Clements Markham, Head of the India Office in London, and by Joseph Hooker, Director of Kew Gardens, to gather seeds of the Havea brasil-iensis from the Brazilian rain forests. He smuggled out some 70,000. There are many stories attached to this venture – not least of all due to the vivid tales related by Wickham himself. According to his accounts, the seed smuggler would have faced the death penalty had he been caught by the Brazilian authorities (see page 14).Whatever the truth of the matter – there is no doubt Wickham had 70,000 seeds with him when he returned to England on the steamship “Amazonas”, which had been lying in wait for him outside the harbor of Manaus. In Kew Gardens, Hooker and his gardeners cultivated 2,000 seedlings that were then shipped out to Ceylon. Apparently only seven of the plants survived the voyage – yet still enough to estab-lish generations of rubber that were to form the basis of all the plantations now found in south-east Asia. Today, on Sumatra alone, millions of identical plants are grown – genetically modified through grafting and

olorem nis ationsecte mod tionsequat lore

deliquam velis ations-

The first person to achieve the synthesis of artificial rubber was the German chemist Dr. Fritz Hofmann, who worked for the Elberfeld-based company known at the time as “Farben-fabriken vorm. Friedr. Bayer & Co.”. The basic patent for “processing synthetic rubber” was granted by Germany’s Imperial Patent Office on September 12, 1909. Hofmann was to receive a number of awards and distinctions for his scientific work: among them the Fischer Medal in Gold from the Society of German Chem-ists, an Honorary Plaque from the German Rubber Society and the gilded Buna medal at the World Exhibition in Paris. Even though Hofmann’s process initially only applied to the manufacture of hard rub-ber, it nevertheless provided

the basis for making styrene butadiene rubber, which was produced on a major industrial scale from 1938 onwards. Hofmann, who was born in Kölleda near Weimar on November 2, 1866, attended school in Klosterdonndorf and Schulpforta before taking up practical training as a pharmacist in an apothecary in Göttingen. After this, he studied pharmacy in Berlin and then chemistry in Rostock. There, he obtained a doctorate “magna cum laude” in philoso-phy. Prior to joining Bayer in 1857, he taught for two years at the Technical University of Aachen. At the age of 85 Hofmann gave a talk to his old school about his life and work researching rubber. Here are a few short extracts from the lecture:

“As the head of various research laboratories I was constantly on the lookout for promising areas of work for my staff. Here [in the manufacture of synthetic rubber] I saw the opportunity to create some-thing that was lacking in my own country and, at the same time, would free it from having to import an expensive product from foreign countries that were naturally blessed with it… In response to my written proposals… the Farbenfabriken company in Elberfeld granted me the initial sum of one million marks to be paid in 10 annual installments of 100,000 marks each. Well, if only it had remained at that figure of one million. Instead, the insatiable needs of research swallowed up that amount several times over...”

Hofmann also described the inadequacies of his first synthetic rubber, in particular its low resistance to tension. He went on to outline later research work, including the heating process of emul-sion polymerization which ultimately was to produce butadiene rubber, Buna.Fritz Hofmann died in Hanover in 1956 at the age of 90.

FATheR OF synTheTIC RubbeR

crossbreeding to enhance quality and yield. As early as 1910, Asian plantations had reached the same level of production as those in the Amazon. As a result, prices for rubber fell – and, with them, share prices on the stock exchange. Thus the Brazilian rub-ber monopoly came to a rude and abrupt end. Soon natural rubber was facing competition of a new kind. This time, it was from the laboratories of Bayer-Elberfeld, where in 1909 a team headed by the chemist Fritz Hofmann succeeded in polymerizing the hydrocarbon isoprene, which forms the basis of natural rubber. The German Imperial Patent Office then granted the chemical plant of Friedr. Bayer & Co. in Elberfeld the patent number 250 690 for “the process of producing synthetic rubber”. The initiative for Hofmann’s research came from Carl Duisberg, who saw the prospect of making money out of the rapidly growing demand for rubber in the tire and electrical industry. Industrial production of Hofmann’s methyl rubber commenced during the First World War – primarily for application in the construction of submarines – after Germany had been cut off from supplies of natural rubber. However, before industrial production of synthetic hard rubber could begin, supplies of acetone had to be secured. This was because it was no longer possible to import the gray lime required for producing acetone. The problem was overcome through the invention made by the Consortium of the Electrochemical Industry (Wacker-Chemie). Even before the outbreak of war, the chemists Wol-fram Haehnel and Willy O. Hermann had found a way of making acetone by splitting acetic acid through



Fritz Hofmann, a chemist at Farbenfabriken, vorm. Friedr. Bayer, invented synthetic rubber.

The train of deathThe construction of the rubber railway through the Brazilian rainforest at the beginning of the 20th century cost at least 6,000 lives. But no sooner was the railway line finished than the rubber boom in Brazil came to a standstill.

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heat. This “acetone process”, which initially had been of no economic interest, now meant it was possible under the conditions of a war economy to produce synthetic rubber at the industrial plant in Leverkusen. In the period leading up to the end of November 1918, the factory turned out a total of 2,400 tons.

The “birth” of Buna®

However, at that time the Hofmann process was still too costly and uneconomical for industrial use – which is why research and development in Germany was discontinued between 1919 and 1925. After Germany’s chemical industry was amalgamated to form the single company IG Farbenindustrie AG in 1925, major research teams set about developing various types of rubber between 1926 and 1931. On June 21, 1929, IG Farben received the first patent to produce synthetic rubber made from hydrocarbon butadiene and sodium (in German “natrium”). It was given the name Buna, taken from the first two letters of “butadiene” and “natrium”. It was the chemical engineers Walter Bock and Eduard Tschunkur who laid the foundations for the economic breakthrough of Buna®. Their process of co-polymerizing styrene and butadiene in an aqueous emulsion marked the “birth” of Buna® S. A year later, Helmut Kleiner, Erich Konrad and Eduard Tschunkur developed the anti-soaking formula of acrylonitrile-butadiene rubber Buna® N, which was used to make

oil- and petroleum-resistant rubber goods and was re-named Perbunan® in 1938. In the wake of progress towards the mass production of synthetic rubber came the discovery of auxiliary products such as anti-oxidants, polymerization ac-celerating agents and fillers.

First industrial production On the basis of a series of research findings, Germany was in a position to commence industrial production of the synthetic rubber Buna® S in 1936. It was spe-cifically for this purpose that IG Farben – under some pressure from political leaders – built a huge plant in Schkopau near Halle. Two more were to foll ow, one of them at the notorious site close to Au schwitz. Towards the end of the Second World War the company’s total capacity of synthetic rubber reached 170,000 tons annually. The first motor vehicle tires with Buna® S were presented to the public at the Automobile Show in Berlin in 1936. They captured the headlines in a big way – not surprisingly, since these tires were capable of running for up to 36,000 kilometers, far more than the mere 29,000 kilometers of natural rubber ones. The world’s first tires for cars and small trucks based 100 percent on Buna® S were manufactured in 1942.

Mass producer USAThe United States of America, too, drastically stepped up its capacity of synthetic rubber production on finding itself cut off from natural rubber supplies during the Second World War. This was due to Japan occupying large parts of the natural rubber-growing regions in south-east Asia. The American rubber pro-gram was based indirectly on the invention of Buna® S dating back to 1929 in Leverkusen. It marked a major breakthrough in making synthetic rubber the mass raw material used for manufacturing tires. By 1945, American production had reached 820,000 tons – seven times more than IG Farben.After the Second World War, German companies were initially forbidden from producing synthetic rubber. Not until 1952 was Germany allowed to resume production. From then on, its rubber-related industries, and in particular the company Bayer AG, concentrated on the manufacture of different types of synthetic rubber with specific properties. Although the tire industry, which now accounts for 60 percent of world-wide sales, is by far the largest consumer of synthetic rubber and rubber chemicals, there are a large number of technical products that could either not function at all or only for a short time without the hundreds of rubber variants, both standard and customized, on the market. These can be anything from simple washers, V- or cog belts in automobiles or machines, insulation material in the electrical

Patent On June 21, 1929 IG Farben obtained a patent for Buna® synthetic rubber that to this day remains a component of car tires.

Milestones1929

breakthroughIn 1929 the chemists Walter Bock and Eduard Tschunkur (below) de-veloped …

… emulsion polymerization from butadiene and sty-rene, known as Buna® S.

The rubber industry is not just about tires. It also produces rubber soles and heels for shoes.

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industry, shock-absorbing buffers in car engines, oil-resistant fuel pipes and elastic hydraulic cables to heat- and cold-resistant encasing material. Thanks to their flexibility, technical rubbers also play a valu-able, if not indispensable role in the exploitation of mineral oil. Without modern types of rubber such as Therban® (HNBR = hydrogenated nitrile-butadiene rubber), Levapren®, Levamelt®, Baymod® L (EVA = ethylene-vinyl acetate rubber), Baypren® (CR = chloroprene rubber), Krynac®, Perbunan®, Baymod® N (NBR = nitrile-butadiene rubber), Arlene® and Kernel® (styrene-butadiene rubber) and Buna® EP (EPM/EPDM = ethylene-propylene rubber) we would have no mobility, complex mechanical engineering, transmission of electricity, space exploration, modern architecture or exploitation of raw materials.

Promising perspectives The range of application for technical rubbers is by no

means exhausted. Wherever there is technical progress in the automotive industry, in the production of energy from wind and sun, in aerospace, in construction, in nano-technol-

ogy and in the manufacture of sportswear and mats, technical rubbers and rubber chemicals will never be far away: invisible ingredients without which ideas cannot be turned into reality for the benefit of us all.

self-sufficiency through buna® sThe second attempt at producing syn-thetic rubber almost failed like the first. Whereas in 1919 Bayer factories were forced to stop the first-ever production of methyl rubber on an industrial scale because natural rubber had become so cheap and abundant, the second half of the 1920s saw renewed interest in the further development of synthetic rubber. Rapid advances in motoriza-tion increased the demand for tires for automobiles and motorbikes, which, in turn, pushed up prices for natural rubber. As a consequence, the newly founded company I.G. Farbenfabriken decided to resume research based on a cheaper process for manufacturing butadiene. In Leverkusen, Eduard Tschunkur and his colleague Walter Bock were placed in charge of the task. To begin with, they developed a safely functioning polymerization process in an aqueous

emulsion. Then Walter Bock suc-ceeded in co-polymerizing butadiene and styrene. This rubber was suitable for manufacturing not only car tires but also technical rubber goods. On June 21, 1929, I.G.Farben was awarded the patent for butadiene-styrene copoly-merization, and on July 5, 1930, had Buna® registered as a trademark. In the same year, on April 25, the nitrile rubber, which had been developed un-der the leadership of chemical engineer Helmut Kleiner particularly because of its distinctive oil- and gasoline-resis-tant properties, was patented. (It was re-named Perbunan® in 1938).In 1932, though, this promising stage of development looked as if it might come to an abrupt end. With prices for natural rubber falling once more, the viability of producing Buna® on an industrial scale was again called into question. However, after the National Socialists had taken over power, priorities soon changed. On July 5, 1933, I.G. Farben decided to resume the research, but initially on a limited scale. However, only a year later, in 1934 – and in no small part due to the drive for self-suf-ficiency on the part of political leaders – the company advanced a plan to build

a large plant for producing synthetic rubber. For cost reasons, the managers responsible for the project at I.G. Far-ben opted for the manufacture of Buna® S. And so, in 1935, the construction of the factory was started in Schkopau in East Germany, since it was here that the chemicals industry had already established an organized network for raw materials and utilities for their plants in central Germany. Production commenced less than two years later, in January 1937. Soon the company was turning out around three quarters of the synthetic rubber manufactured in Germany. The “Four Year Plan” for the economy, drawn up under the auspices of Her-mann Göring and announced by Adolf Hitler on September 9, 1936, provided for a total of four major rubber facto-ries. Three of them – Schkopau, Hüls and Auschwitz – were, in fact, built, producing almost 120,000 metric tons of Buna® S in the record year of 1943.The plant in Hüls was bombed several times during the War and completely destroyed in March 1945. The Buna factory in Schkopau was placed under Soviet administration at the end of the War, and in 1954 was taken over by the East German state and became one of the country’s largest chemical companies at that time. In the western half of Germany, the Allies prohibited the manufacture of

synthetic rubber in 1948, but following intervention by Economics Minister Ludwig Erhard, Germany was allowed to gradually re-start production from 1951. Within just a few years Bayer managed to close the gap that had existed in the field of research and development. In 1955, Buna-Werke Hüls AG was founded in Marl near Recklinghausen as a joint-venture of the three I.G. firms Bayer AG, BASF AG and Hoechst AG. At that time it was Europe’s most modern factory for the production of synthetic rubber. In 1994, Bayer AG took over most of the rubber business from Hüls AG. It was later transferred to LANXESS AG, which was founded as a new company in 2005. Today, LANXESS is one of the world’s largest producers of synthetic rubber.


1936 The first car tires with treads made out of Buna® caused a stir at the Automobile Show in Berlin in 1936.

Production of the synthetic rubber Buna® S began at I.G. Farben’s sites in Schkopau in 1937.


2000This is what the bale of syn-thetic rubber looks like as it leaves the production unit.

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RUBRIK

The potential uses for synthetic rubber have been far from exhausted. The future offers plenty of opportu-nities.

THE LANXESS STORY

A young company with strong roots

Carl Duisberg was a highly influential figure in the development of the German chemical industry from 1884 to 1935.

LANXESS’s present headquarters, K 10, a building steeped in tra-dition at the Leverkusen Chemical Park.

Many successful, long-standing companies have un-dergone more than one transformation in their time. Technological progress, macroeconomic and political change, new markets, new products and lines of busi-ness, new competitors and new faces at the top all trigger structural and organizational changes over the course of a company’s history. In fact, some theorists and economists believe that the only constant is change. One leading German chemical company owes its in-dependence to being able to adapt to the ever-chang-ing market conditions. LANXESS AG, a separate legal entity since January 2005, and the fourth biggest German chemical company, arose out of a trans-formation process at Bayer AG. LANXESS AG was

listed on the Frankfurt Stock Exchange in Germany on January 31, 2005. A few days previously, LANXESS AG had been entered into the commercial register – marking the point when the spin-off from the Bayer Group first put down roots in the capital market. In the meantime, this spin-off has developed into a veritable company, generating almost EUR seven bil-lion in the last financial year (2007) and recording an operating result before depreciation and amortization (EBITDA) of around EUR 700 million.The journey has not always been easy, and has demanded a lot of hard work and sacrifices from both management and employees alike. Right from the word go, LANXESS was faced with a number of key tasks – the adopted portfolio had to be stream-

Early visionary

for industrial research in Wuppertal-Elberfeld, which produced numerous intermediates and new dyestuffs. Last but not least, it was here that Felix Hoffmann developed the “drug of the century” Aspirin, which was launched onto the market in 1899.Duisberg served as Chairman of the Board of Man-agement from 1912 to 1925. In 1912, he relo-cated the company’s headquarters from Elberfeld to Leverkusen. During the First World War, Bayer launched its production site in Dormagen. At the end of the war in 1918, Bayer lost all of its foreign assets and export markets remained initially inaccessible. In the United States and other countries, the company even lost its patents and trademarks to competitors. It was only after the inflation of the post-war period from the mid-1920s that the situation began to sta-bilize. In 1925, major German chemical companies merged to form I.G. Farbenindustrie AG. Yet the Bayer tradition lived on in the I.G.’s Lower Rhine operating consortium. Leverkusen became the headquarters for the I.G.’s pharmaceutical sales association. Rubber synthesis and modern polymer chemistry were the focus of research activities at this time. The economic recovery of the “Golden ’20s” was short-lived, coming to an end on October 29, 1929 as a result of the worldwide economic crisis triggered by the crash of the New York stock exchange. During the National Socialist regime, the Lower Rhine consortium was increasingly integrated into the preparations for war. At the outbreak of the Second World War in 1939, all the company’s sites were considered “vital to the war”.

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lined and reorganized, the company’s presence on growth markets had to be established or expanded, its competitiveness in strategic areas of growth had to be strengthened through initial acquisitions, and its operating results had to be improved considerably. In just three years, LANXESS has made significant progress in its restructuring project and in setting the course for expansion. The stockholders profited from these developments. When LANXESS was floated on the stock market on January 31, 2005, its shares were worth EUR 14.84. By December 31, 2007 they had more than doubled to EUR 33.60.

The company’s rootsThe young company’s initial successes were fa-cilitated thanks to the backing of over 140 years of family history. LANXESS was able to build on a strong foundation.A brief overview of developments: On August 1, 1863, dye salesman Friedrich Bayer and master dyer Johann Friedrich Weskott founded the general partnership “Friedr. Bayer et Comp.”. As a result of their experiences in the thriving textile indus-try, the two business partners recognized the potential that inorganic chemistry offered for the production of dyestuffs. At this time, natural dyes extracted from dyewoods and minerals dominated the market. Synthetic dyes from coal-tar derivatives, such as aniline and alizarin, had only been invented a few years previous to the company’s foundation. These new products opened up a promising new field of business for the still-young chemical industry. Thanks to the superior quality of their products, Bayer and Weskott quickly gained a foothold on the market as suppliers to the textile industry.Dyes remain a key area of interest for LANXESS today, with organic and inorganic pigments giving plastics, coatings, inks – and even concrete and paving stones – the required color. When Friedrich Bayer died in 1880 at the age of 55, he left behind a flourishing business with over 250 employees. His successors – all sons and sons-in-law of the two founding fathers – transformed the company into a joint stock company in 1881 called “Farbenfabriken vorm. Friedr. Bayer & Co.”.

Eventful timesBefore the outbreak of the First World War, Bayer developed into a chemical company with international operations. During this time, Bayer expanded its focus from dyes to include organic base products, interme-diates and, from 1888, pharmaceuticals. One name associated very closely with the company is Carl Duisberg. He was the driving force behind the expansion of Bayer’s research and development activities from 1884, founding a scientific laboratory

Eingebauter Feuerschutz

Drawing from 1938 of the first German Buna site in Schkopau.

This was what LANXESS’s present headquarters looked like on January 28, 1941.

Perbunan® unit in the rub-ber pilot plant in Building K 10 at the beginning of January 1945.

Stages in Build-ing K 10’s history

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THE LANXESS STORY

When Herbert Grünewald took over from Kurt Hansen as Chairman of the company‘s Board of Management in 1974, the first oil crisis of 1973/74 ended the economic miracle of the post-war period once and for all, affecting the company and the entire western economy. Within just a few months, prices for chemical raw materials based on oil had quadrupled. Despite the unfavorable environment, Bayer AG con-tinued to step up its activities at home and abroad, particularly in the United States. By the second half of the 1980s, sales outside Germany accounted for 78 percent of the Bayer Group’s total sales, with 45 percent of employees working abroad.In 1988, Bayer celebrated the 125th anniversary of its founding. Sales that year amounted to roughly DM 40 billion, while the company employed a global workforce of more than 165,000.In 1984, Hermann Josef Strenger took over as Man-agement Board Chairman from Herbert Grünewald, who switched to Chairman of the Supervisory Board.During the 1990s, the political changes in Central and Eastern Europe influenced the activities of the

When the Board of Management and the headquarters of LANXESS moved into the K 10 building at the Leverkusen Chemical Park in 2005, the impressive industrial building had already had an eventful past spanning almost 60 years. The building was built thanks to the initial surge in demand for synthetic rubber during the second half of the 1930s: In 1936, Buna® S went into mass production in the newly built Schkopau plant belonging to what at that time was IG Farben and the rubber processing industry unveiled the first automobile tires featuring a tire tread made of Buna® S. However, this was merely the start of things to come, since the striving for self-sufficiency at that time gave rise to expectations of a real boom in syn-thetic rubber. In order to rapidly push ahead with the further development of synthetic rubber, IG Farben’s Board of Management decided in 1936 to build a central laboratory for rubber – a “multipurpose building for research, application technology and small-scale production”, including a small rubber pilot plant – the K 10 building. Probably planned by the company’s internal building department, the building, which was originally U-shaped, was first commissioned in 1939. Even today, K 10, built in a lin-ear, industrial style, featuring a dark red exterior made from Burscheid clinker bricks, is deemed to be one of the most successful buildings on the former Bayer site.

The size of the building, which has a volume of 110,000 cubic meters, and the original cost of its construction, which amounted to around 3.5 million Reichmarks, highlight how important research into rubber was at that time.Although the Allied Forces banned the production of synthetic rubber six years after it had started, following the end of World War II, research in the K 10 building continued largely unrestricted, even being extended.After Bayer AG was founded in 1952, the purpose of the building gradu-ally began to change, which can also be seen in the rejection of the name “Central Laboratory for Rubber”. K 10 now housed the “Rubber and Plastics Division” which formed part of the “Application Technology Department”. The dynamic development of the post-war period and the first few years of the “Wirtschaftswunder” soon caused research capacities to reach their limits as far as space was concerned. An extension was there-fore built in 1956 which closed off the open side of the original U-shaped building.At the end of the 1970s, the extended building was also no longer able to cope with the demands placed on it by chemists and technologists. Since plans to build another extension fell through due to it being too expen-sive, a large part of the laboratory division dedicated to research into rubber was moved to Dormagen. Meanwhile, the K 10 premises were

largely converted into offices to house management, planning and administrative staff. Only the Applica-tion Technology division with a few testing laboratories and a pilot plant remained in the K 10 building. In the early 1980s, the Personnel Division took over areas of the build-ing and used them as staff rooms. After being temporarily shared by the Central Engineering Division and the Central Research and Development Division, K 10 was commandeered to house management and the staff department of Bayer AG’s Rubber Business Group in 1995, with the Polymers Business Group (respon-

sible among other things for rubber and plastics) taking over the entire building at the end of the 1990s. This saw K 10 finally converted into an ad-ministrative building, with one small, but not insignificant exception: The polymer testing laboratory belong-ing to the Technical Rubber Products Business Group with its modern test-ing devices (see page 38) continued a longstanding tradition. This is now a division of LANXESS.

BUILDING WITH A HISTORY MARKED BY CHANGE

RecoveryAfter the end of the war, the British Forces took over complete control of the Lower Rhine consortium in June 1945. The Allied Forces confiscated the I.G. in December 1945. When I.G. Farben was broken up into 12 new companies on the territory of the Federal Republic of Germany, Farbenfabriken Bayer AG with its sites in Leverkusen, Dormagen, Elberfeld and Uerdingen regained its independence on December 19, 1951 under the leadership of Ulrich Haberland. A year later, Bayer also received the newly established Agfa “joint stock company for photofabrication” as a subsidiary. Bayer’s entry onto the petrochemical market was one factor that drove the company’s rapid and sustained recovery during the economic miracle in the Federal Republic of Germany from the mid-1950s. In 1957, for example, Bayer joined with Deutsche BP to found Erdölchemie GmbH in Dormagen.By 1963 – 100 years after its founding – Bayer em-ployed nearly 80,000 people and sales had grown to approximately DM 4.7 billion.

Products from K 10

1937: Building of the Central Laboratory for Rubber. In the back-ground, the K 19 building

1940: A boot fitted with a rubber sole is given the finishing touch.

percent voted in favor of carving out LANXESS. The process was finally completed on January 31, 2005 when LANXESS was listed on the Frankfurt Stock Exchange. LANXESS was incorporated into the MDAX on June 20.For quick implementation of the planned restructur-ing measures, the management and General Works Council agreed a solidarity package on July 19, 2005 to ensure a socially acceptable solution to job cuts. One of the first groundbreaking restructuring activities in April 2006 was the spin-off of the Fine Chemicals business unit into an independent company (GmbH) under the name Saltigo. This global subsidiary devel-ops and customizes industrial solutions to customer order. In view of the specific requirements of its wide-ranging customers, Saltigo operates three business lines – Pharma, Agro and Specialty Chemicals.LANXESS invested EUR 30 million in the new sites to boost Saltigo’s business. This investment was used to modernize the existing production facilities at the sites in Leverkusen and Dormagen and adapt them to the ever-changing market requirements. A further EUR 10 million is being invested in a state-of-the-art multi-functional plant. While the restructuring activities gradually improved the earning power, the management team continued to streamline the company’s portfolio. In December 2005, LANXESS sold its Dorlastan fibers business to the Japanese company Asahi Kasei Fibers and its Paper business unit to the Finnish Kemira Group.In the second financial year, LANXESS continued the necessary cut-backs and began to expand its ABS

Bayer Group. The company stepped up its activi-ties here, but without neglecting the markets of the United States, Europe and Japan. For example, Bayer founded its third research center in Japan under the leadership of Manfred Schneider, who took over as Chairman in 1992.

Process of independenceA key date in the development of LANXESS AG is July 1, 2002, when the Bayer Group reorganized to create a new structure with four operational subgroups and three service companies. In November 2003, Bayer AG’s Board of Management decided to focus on the areas of health care, nutrition and high-tech materi-als. The traditional chemical activities and parts of the plastics business were to be split off from the Group and made independent. After the Board’s historical decision in November 2003, project teams began to plan the structures and organi-zation of the future chemical company LANXESS. The employees responsible for the restructuring process decided to subdivide the activities into four segments – Performance Chemicals, Chemical Intermediates, Engineering Plastics and Performance Rubber.The new company was launched within the Group’s framework on July 1, 2004. From now on, LANXESS operated as an independent company with its own financial reporting system.

The restructuring processOn November 17, 2004 at an Extraordinary Stock-holders’ meeting, an overwhelming majority of 99.66

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Sites

In Thane in India, LANXESS annually pro-duces 6,000 metric tons of rubber chemicals and oper-ates a research laboratory.

1962: Production of rub-ber gloves in the rubber pilot plant housed in the K 10 building.

LANXESS’s head office in Japan is in the central business quarter of Marunouchi in Tokyo.

In Bitterfeld LANXESS runs a highly modern production facility for ion exchange resins.

The Leverkusen Chemi-cal Park, from where LANXESS’s worldwide business is run.

the past few years, LANXESS has also rapidly stepped up its activities in Indonesia, Thailand and Vietnam.In the summer of 2007, the company began con-struction of a plant for the production of ion exchange resins in the Indian State of Gujarat. The new plant, which will cost around EUR 30 million, is scheduled to come on stream at the start of 2010. In mid-2007, LANXESS also announced plans to invest some EUR 400 million in a new butyl rubber plant in Asia.

Continued globalizationIn addition to realizing its strategy in Asia, the com-pany also expanded its presence in other parts of the world. For example, at the start of 2007, LANXESS made its first acquisition since its foundation and took over the activities of the Dow Group in South Africa, thereby establishing the company as one of the world’s biggest chrome producers for the chemical industry. Acquiring an initial 70 percent share in the Brazilian company Petroflex S. A. (a listed company headquar-tered in Rio de Janeiro), LANXESS also strengthened its worldwide rubber activities. With some 1,300 employees at three sites in Brazil, Petroflex generates sales equivalent to more than EUR 500 million. The company’s annual production of over 400,000 met-ric tons of rubber ranges from solution to emulsion rubbers, primarily for the tire industry. This acquisi-tion represented a major step forward in LANXESS’s globalization strategy. The Leverkusen-based chemical company also expanded its butyl rubber activities in Sarnia, Canada. On conclusion of the first expansion stage at its Sar-nia plant in mid-2007, the local production capacity rose by 42 percent.The course is set for further growth in the coming years now that LANXESS has made significant prog-ress in its restructuring process. After the divestment of the Lustran Polymers business unit, LANXESS will position itself in future at the heart of the chemi-cal industry as a specialist chemical group focused on the segments Performance Polymers, Advanced Intermediates and Performance Chemicals. The main priorities will be to further strengthen the company’s earning power and expand its position on the growth markets.

Sites

THE LANXESS STORY

Administrative center of LANXESS Emulsion Rubber at La Wantzenau in France.

plastic production in Tarragona, Spain. The European management team and marketing department of the Styrenic Resins business unit was also relocated here.At the end of August 2006, this business unit was re-named Lustran Polymers in reference to the compa-ny’s top product Lustran®. 11 months later, LANXESS set up a joint venture between its Lustran Polymers business unit and the British chemical Group INEOS, with the aim of divesting itself completely of this area within two years. A new home was also found for the chemicals used in textile processing. At the end of December 2006, the Dutch investor Egeria and the business unit’s man-agement team took over much of the business.

The Asia strategyThe streamlining of the portfolio went hand in hand with the expansion of activities, particularly in Asia. At the end of April 2006, LANXESS opened a new site for high-tech plastics in China, and took an extended production plant for rubber additives into operation in India. July 2006 saw the inauguration of a new hydrazine hydrate plant in Weifang, China. As part of its Asia strategy, LANXESS opened a new plant in Shanghai in the spring of 2007, the second produc-tion facility for the production of inorganic pigments in China. The new development center for high-tech plastics was launched in Wuxi, China in May 2007. In

All the LANXESS business units are represented in the company’s offices in the South Korean capital Seoul.

LANXESS serves the en-tire Chinese market from its office in Shanghai.

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LANXESS runs its south-east Asian business from Singapore.

In Brazil LANXESS has acquired a majority share in Petroflex S.A. with its three sites.

Production plant for butyl and halobutyl rubber in Sarnia, Canada.

MF 2525

Good chemistry

with “conventional” rubber crosslinking with sulfur bridges, it forms much more thermally stable, flexible hybrid crosslinks. As a result, when exposed to heat up to 180° C, the rubber-elastic properties of the rubber are preserved significantly longer than in conventional blends. The vulcanization temperature can therefore be raised, which considerably increases productivity for the manufacture of large rubber articles, such as tires for trucks or construction machinery.Vulcuren® has now proven in road tests that it addition-ally counteracts the abrasion of NR, BR and SBR rubber products in truck tires. But advantages are found else-where as well: dynamic tests with heat-induced aging show that the stability of passenger car tires increases significantly when Vulcuren® is used in their manufac-ture. This factor plays a very important role in the market segment for ultra-high-performance tires.Lastly, one of the most successful specialty products for the rubber industry is Zinkoxyd aktiv®, the vulcanization activator from LANXESS. Without zinc oxide, organic vulcanization accelerators are not even half as effective and are forced to function below their potential. The use of Zinkoxyd aktiv® is most widespread in the latex seg-ment, because it results in more homogeneous surfac-es, improves fatigue resistance and ensures high elastic-ity for products subjected to strong dynamic loads.Together, LANXESS rubber chemicals make a signifi-cant contribution to promoting rapid expansion of the company in high-growth regions of the world, and to supplying the rubber industry with innovative new prod-ucts and product families, both today and in the future.

LANXESS offers the global rubber industry a broad range of chemicals.

Rubber blends frequently require the addition of special chemicals to give them the “finishing touch”. These special chemicals prevent premature aging and embrittlement of vulcanizates caused by exposure to oxygen, ozone or other chemicals, serve as crosslinkers and anti-reversion agents during the vulcanization of natural and synthetic rubber to stabilize the material, or accelerate mastication (mechanical, thermal, chemical reduction of rubber viscosity, e.g. in the internal mixer), which saves time, money and capacity. Renacit® from LANXESS, for example, is a peptizing agent that fulfills these demands.Based in Leverkusen, Germany, LANXESS is a global chemical company that commands around 20 percent of the market, making it one of the largest manufactur-ers and suppliers of rubber chemicals worldwide. It offers the broadest range of products and maintains production sites close to its customers in Europe, the United States, South Africa and now also in China.Some 70 percent of all antioxidants, vulcanization accelerators and specialty chemicals go to the tire industry, while the remaining 30 percent are processed in the technical rubber and latex product segments.

Commodities and specialty productsKey products in terms of volume include Vulkanox® antioxidants and Vulkacit® vulcanization accelerators. The Rubber Chemicals business unit is one of three leading global suppliers of these products. Capacities in the antioxidant segment are to be selectively expanded. For example, LANXESS has established the Anhui Tongfeng Shengda Chemical joint venture in China, which has been producing Vulkanox® 4020 in Tongling, 500 kilometers west of Shanghai, since the second half of 2006, thus enabling LANXESS to participate in the above-average growth of the national and international tire industry in China. Apart from commodities like Vulkanox® and Vulkacit®, Rubber Chemicals also markets an extensive portfolio of specialty products, such as the antioxidant Vulkanox® HS HPG (high purity grade), which has been available since early 2007 and is characterized by, among other things, a very low amine content (compounds derived from am-monia); and the Renacit® line of peptizing agents, which recently was expanded to include Renacit® RUC 9205; and the antiozonant Vulkazon® AFD, which protects rub-ber from degradation due to ozone without discoloring it. Vulkazon® AFD can be used in all light-colored rubber articles, such as bicycle and passenger car tires, or good quality windshield wipers.

New family membersSome of the latest developments also include Vulcuren®, a crosslinking and anti-reversion agent. In comparison

RUBBER CHEMICALS

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Therban®

Fritz Hofmann invented methyl rubber in 1909. By the 1970s, the rubber chemists in Leverkusen had instilled many good and useful benefits into their synthetic products on the basis of his development. The chemists Walter Bock and Eduard Tschunkur laid the foundation for the economic breakthrough of syn-thetic rubber with the invention of the butadiene-sty-rene copolymer Buna® S, which was the first synthetic rubber to be taken into industrial-scale production in 1936 and soon went on to be used for the tread in car tires. The team comprising Helmut Kleiner, Erich Konrad and Eduard Tschunkur developed the acrylo-nitrile-butadiene rubber Perbunan® in the mid-1930s. A key feature of this elastomer was that it repelled oil and gasoline practically from the inside. The rubber chemists incorporated this talent into the long chain molecules with the nitrile group (hence the abbrevia-tion NBR, nitrile-butadiene rubber). These molecule traces in the chain prevent the rubber soaking up liquids such as oil or gasoline, thereby causing it to expand to more than twice its original volume.

The right material for shaft sealsOne of the products that owes its breakthrough to this invention is the radial shaft seal. These seals are used to close off the openings of a machine’s rotating shafts against the ambient conditions. Walter Sim-mer, the inventor of these types of seals, first experi-mented with rings made of leather belts. However, they quickly became slack and could not be pressed tightly enough against the rotating shaft. On the other hand, the natural and synthetic rubbers available on the market at the time were sensitive to the transmis-sion oils that they were supposed to stop leaking out. Perbunan® was the material that put Simmer’s seals on the map and secured their worldwide success.

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One innovation leads to another…

Therban® production in the highly modern facil-ity in Leverkusen.

Material & product

Granules out of which high-quality and high-performance elastomer products are produced.

Thanks to its outstanding resistance to mechanical and thermal stresses, the high-performance rubber Therban® can cope with the most difficult of condi-tions.

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Perbunan® was followed by other types of artificial rubber, such as polybutadiene (PBR), styrene-butadiene rubber (SBR) – which is vital today for car tire production – and specialties such as the weather-proof chloroprene rubber (CR) Baypren®, which is processed into protective clothing for surfers and divers. More than 20 high-performance rubbers and related materials have since been added to the port-folio for special high-performance applications. However, rubber was still not suitable for all applica-tions – at least not until the early 1980s. The com-mon rubber grades available on the market at that time, such as nitrile rubber, had one distinct disad-vantage – they did not tolerate high temperatures, which means they were susceptible to hot air. Like most other elastomers, Perbunan® chain molecules are littered with points of attack for oxygen and ozone – double bonds that are left over from the production of molecule threads of smaller components (from the butadiene). In hot air, oxygen molecules/ozone pen-etrate the rubber and split these double bonds – like butter that has been left in the sun for too long. In both cases, the oxygen/ozone leaves behind shorter molecule fragments, causing the butter to smell bad and, in the case of rubber, ruining its physical proper-ties. High temperatures and mechanical loads cause cracks to form and the material loses its elasticity – a

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nightmare, for example, for engine designers whose latest products generate temperatures of around 150° C under the hood as a result of increased en-capsulation (due to reasons of noise) and the greater power of the transmission equipment. Moreover, the lubricant additives for engines designed to deliver peak performance are becoming increasingly aggres-sive, and they too attack the double bonds.There are chemical methods designed to counteract oxygen, such as antioxidants (molecules that attract aggressive gases), but the only real solution is to eliminate the double bonds from the rubber chain molecules.

Fight against the double bondsChemists have known that it is possible to eliminate these double bonds since the mid-1970s. It was then that scientists in the Bayer Group laboratories began searching for methods to eliminate double bonds from Perbunan® rubber molecules for example, with-out damaging the sensitive nitrile groups in the rub-ber. They quickly found candidates for this process – catalysts comprising the metals rhodium, palladium and ruthenium, which the chemists have instilled with properties to trigger specific reactions. For instance, they can cause Perbunan®, added to a solvent, to react with hydrogen. The hydrogen occupies the

Quality parameters

The Therban® facility in Leverkusen has been in operation since the begin-ning of the millennium.

View of the Therban® facility in Leverkusen.

Therban®

Sealing rings made of Therban® are distinguished by their versatility and high level of resistance to high temperatures and aggres-sive media.

Toothed belts made of Ther-ban® also perform a variety of functions in high-per-formance engines such as state-of-the-art diesel units.

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Therban® in 1981. No one is sure where the name comes from, but the developers may well have been inspired by the idea of “thermally stable Perbunan®”, as the new material from the Dormagen rubber cruci-ble proved to be extremely heat-resistant. It withstands operating temperatures of up to 150° C – around 20 to 30 degrees more than most other rubber materials – without any problems. It has also inherited the oil and fuel resistance of Perbunan® and, like Perbunan®, its low-temperature flexibility can also be adjusted by varying the nitrile content. What’s more, Therban® is virtually impenetrable to gases, and withstands UV and even radioactive rays without decaying. And, most importantly, Therban® is a true rubber raw material. It can be used to vulcanize elastic molds with outstand-ing damping features and a low compression set, which can easily compete with technical molded parts made of other grades of rubber.Gradually, the researchers learnt to vary and optimize the material. Using sophisticated process engineer-ing, they were able to keep between 0.3 and 7 per-cent of the double bonds instead of eliminating them all. A certain proportion of double bonds can be used to vulcanize the material with sulfur systems and bind it, for example, to technical fabrics or surfaces. As the new highly versatile elastomer is resistant to pressure, oil and high temperatures, it is not surpris-ing that the first customers came from the oil industry, fitting the equipment they used to drill for oil with the new Therban® rubber (see page 48). The automotive industry only showed an interest later on, using this material to manufacture hydraulic hoses for power steering, cylinder head cover seals, tie rod bearings, toothed belts, water pump seals and shaft seals. Therban® also proved to be resistant to detergents and a whole range of other chemicals, thus earning food grade approval from the FDA (the Food and Drug Administration in the United States). It is thanks to this institution that Therban® dishwashers (hot lye) and espresso machines (hot steam) remain free of leaks their whole service life. The paper industry also uses Therban® – in fast rotating rollers that demand excellent abrasion resistance and resilience to paper chemicals and inks. Today, 45 percent of this high-end rubber is used in the production of timing belts, 25 percent in seals, 15 percent in hoses, four percent in oil production and a further four percent in cables. The remainder is spread across a number of product areas.

The dream of a new plantAs early as 1984, no more than ten years after the first tentative experiments in test tubes, Bayer invested in a new major pilot plant for Therban® pro-duction. In 1987, plans were also drawn up for a facility with an annual capacity of 1,000 tons. How-ever, these plans initially came to nothing because

points in the rubber molecule that the oxygen needs to wreak havoc. In other words, if there is no point of attack, there can be no attack.

Ingenious process technologyThe first years of research into the material named HNBR (hydrogenated NBR rubber) were turbulent. The high prices of the preferred metal catalysts put the brakes on the project on numerous occasions. Rhodium, for example, is around four times more expensive than gold, so that every gram added to the runny rubber solution to catch hydrogen is vital. By 1980, scientists were able to reduce the amount of catalyst added in the mix to 0.15 percent. From the mid-1980s, they began to work with parts per million (ppm). At the same time, they were also working on ways to recover the expensive metals from the reac-tion solutions and to recycle them. In 1979, “worldwide stocks” of the new super rubber amounted to just a few dozen kilograms that were processed, stretched, bent, dipped in oil and exposed to hot air in test labs. In 1981, the chemists took 200 kilograms out of the reactor for the first time. By 1983, this amount had increased to a massive nine metric tons after a special pilot plant had been set up in Dormagen to boost development work. The promising new material was given the name

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Therban® also provides lasting and reliable seal-ing in espresso machines that have high operating temperatures.

Applications

Therban® acts as a resis-tant and slip-proof shaft sheathing material.

Printing blankets coated with Therban® give news-papers and magazines their colorful gloss.

A combination with a future: An oil pan made of Durethan® with an integrated Therban® seal.

61 million) in a suitable plant in Europe. Construc-tion started at the Chemical Park in Leverkusen on September 15, 1998.

Top technical performanceEngineers, technicians and logistics providers had to work flat out before the projected 3,000 metric tons additional annual capacity could be realized. Up to 200 people worked on the selected site, laying 22 kilometers of pipelines that they connected into a shining silver techno-network at 2,000 different points. Overall, more than 140,000 individual parts had to be fitted together to create this highly complex high-tech system.The biggest challenge turned out to be the installa-tion of the central reactor, in which “normal” nitrile rubber is processed into Therban®. The reactor – some four meters wide, five meters tall and weighing almost 140 metric tons (the agitator alone weighs six metric tons) – cost some DM 5 million (around EUR 2.4 million), making it the most expensive individual item on the construction balance sheet. This giant is not even the biggest component in the Leverkusen Chemical Park. But it’s certainly the only one that can withstand pressure of up to 145 bar, equivalent to 1.5 km below sea level.This oversized cooking pot is fitted with steel walls that are 20 cm thick to enable it to withstand the tremendous pressure. The cylindrical part of the reactor had to be made from a single steel block. After Japanese, Finnish and U.S. reactor specialists had already turned down the project, the Bayer en-gineers found two companies in Saarland, Germany, and France who could build the reactor. Only one manufacturer was in fact able to build the monster’s rounded base. A 1,000-ton crane, with a little help from 20 trucks, was needed to lift the heavy part from the flatbed truck to its position in the hall. Although the installation was planned with military precision, when the day arrived it turned out to be a real cliffhanger. The very day that the reactor was to be installed – March 3, 2000 – gale-force winds ripped through Germany, tugging not only at the steel cables that were as thick as a man’s arm, but also at the nerves of the crane drivers.

High-performance gradesHowever, the new production system by no means represents the peak of Therban®’s development. The demands placed on high-performance rubber continue to rise. Take the automobile industry, for example. The aforementioned rise in temperatures continues, with engineers recording peak tempera-tures in the drive unit of some 170° C, while the continuous temperatures under the hood are nearing 150° C. The solution for loads generated in this way in the hoses and seals combines special antioxidants

Therban®

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WOrthy Of the NObel PrizeThe process of metathesis, which won the Nobel Prize for Chemistry in 2005, allows for the creation of new molecules through a form of partner exchange. The double bonds of organic substances are broken up using catalysts and their atom groups are reorga-nized. Carbon, which forms either long molecular chains or rings, is the defining feature of organic substanc-es. Other elements such as hydrogen or oxygen are bound to them using double bonds. All life on Earth is based on these bonds. They can also be artificially manufactured using a process of organic synthesis.The process of metathesis uses catalysts to break up the double bonds of carbon and reorganize groups of atoms. The Nobel Prize committee described the molecular interactions thus: “It’s just like swapping partners at a dance.” They said that metathesis opens up “fantastic opportunities” in the creation of new molecules, for example in the development of pharmaceuti-cals and plastics.The winners Yves Chauvin, Robert Grubbs and Richard

Schrock were praised for making metathesis one of the most important methods of reaction in the field of organic chemistry. Their research has made the process of synthesis simpler, more efficient and more environmentally friendly.In 1971 at the Institut Français du Pétrole, Chauvin was able to explain in detail how metatheses reactions function and what types of metal compounds could act as catalysts. Schrock from the Massachusetts Institute of Technology (MIT) was the first to produce an efficient catalyst for metathesis in 1990. Two years later,

Robert Grubbs from the California Institute of Technology (Caltech) developed an even better catalyst that was stable in air and found many applications.

Yves Chauvin, Institut Français du Pétrole

Richard R. Schrock, Massachusetts Insti-tute of Technology

Robert Grubbs, California Institute of Technology

other suppliers had begun to work on the hydrogen idea, including the company Polysar, which laid the foundation stone for its HNBR plant in Orange (Texas) in 1987. The plant was commissioned in December 1988, but initially only ran to half its capacity because the new polymer had not yet tapped into the market’s full potential. From 1989, Bayer took advantage of the unused capacities in Orange and started to manufacture its own brand product Therban® there. Just one year later, Bayer acquired Polysar’s Rubber division in its entirety and expanded its capacity to around 3,000 metric tons a year. This meant that the dream of a Bayer Therban® plant in Leverkusen was initially put on the back burner.However, things changed at the end of the 1990s, and the chemists in Leverkusen finally got their “own” Therban® reactor right on their doorstep. And for good reason – the market had proven to be extremely dynamic in the intervening years. Marketing experts calculated that demand had more than doubled between 1992 and 1996, estimating worldwide demand at a good 6,000 metric tons, with figures continuing to increase at a fast pace. On the back of these extremely positive developments, it made perfect sense to invest DM 120 million (around EUR

laying the foundation

When the €60 million production unit for the high-performance rubber Therban® went on stream on October 17, 2000, it had only taken two years and one month to build. The foundation stone had been laid at the Chemical Park in Leverkusen on September 15, 1998. In the implementation of the project the focus was on applying resource-con-serving technologies and environmentally compat-ible processes.

with intelligent chemistry, thus enabling the HNBR rubber to withstand even higher temperatures. The long-term thermal upper limit of the special-purpose rubber Therban® HT is now 165° C. LANXESS chemists are also expanding the Therban® working temperature downwards by integrating large molecule sections into the chain molecule, thus pre-venting the polymer from crystallizing, i.e. hardening, too soon. The product is known as Therban® LT.

Nobel Prize-winning method A third new special-purpose grade – Therban® AT – is a product line that boasts excellent flow behavior, making it the ideal choice for large rubber compo-nents. In the production of Therban® AT, the chem-ists use a reaction method known as “metathesis” in order to produce organic molecules. In this process, the double bond between two atoms is broken down and catalysts are used to attract a different molecu-lar partner to these binding points. Chemists Yves Chauvin (Institut Français du Pétrole in Ruell-Malmai-son), Robert Grubbs (California Institute of Technol-ogy in Pasadena) and Richard Schrock (Massachu-setts Institute of Technology in Cambridge) were awarded the Nobel Prize for Chemistry for their work on this method. Thanks to its optimal abrasion resistance against, for example, rough, coarse sludge, its excellent resistance to aggressive media and chemicals, its high temperature resistance, low tendency to swell, optimal strength in dynamic applications and good adhesion to metals, Therban® AT produced in this way is ideal for a whole range of applications, includ-ing sealings in stator/rotor systems such as eccentric

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interactions

Combining forces, metal and Therban® damp oscil-lations at the drive train of vehicles. The Therban® ring (1) acts as a central damping element between the inner metal ring (2) with the hub (3) as the connection to the shaft and external ring (4).

screw pumps and drill engines for oil production. Compared to the 12,000 kilotons of synthetic rubber currently sold each year, the 12,000 or so tons of HNBR produced annually is rather modest. Neverthe-less, demand is rising in line with the increasingly ambitious requirements that rubber manufacturers and their customers are placing on the performance and flexibility of the rubber material. And there is still a good deal of untapped potential in Therban® and its customized grades.

Hoses made of Therban® withstand heat, oils, fuel and grease even in direct proximity to the engine.

Freight containers glide into the aircraft hold on hard yet at the same time material-saving rollers.

Vibration dampers sta-bilize camshafts and drive trains.

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Levapren® “unfolded” as a transparent tent roof.

Temperature-resistant up to at least 175º C, resistant to UV radiation, ozone and oxygen, impervious to oil and gasoline, impermeable to water and air, safe for man and the environment, highly adaptable and cost-efficient in processing: material properties of this kind are in great demand in the rubber industry, but seldom achieved. One of the few exceptions, however, is Levapren®, developed by the LANXESS chemical company in Leverkusen, Germany. Leva- pren® is a high-quality synthetic rubber manufac-tured in pellet form at a production facility in Dor-magen, Germany. Essentially comprised only of hydrogen, carbon and oxygen, its building blocks are vinyl acetate (VA) and ethylene, which also are the origin of the name: ethylene-vinyl acetate rubber. The abbreviation “EVM” in contrast to “EVA” refers to polymers with a high vinyl acetate content. Synthesis of the two starting materials results in an extraordinarily mobile chain molecule with highly variable properties that can be adapted to differ-ent requirements. For example, a rubber material containing between 40 and 70 percent by weight vinyl acetate displays the sturdiness of polyethylene plastic, without its stiffness. Similarly, as the per-centage of VA rises, so does the oil resistance of Levapren®. In other words, EVM grades with a high vinyl acetate content hardly swell at all even in the presence of hot oil. A rising VA content also changes the polarity: every percentage point of VA content increases the polarity of the polymer, as expressed by a rising electrical dipole moment. Pure polyvinyl acetate is nearly as polar as polyvinyl chloride (PVC). Consequently, Levapren® with a high VA content repels non-polar oil and gasoline practically from the

inside out. Thanks to its polarity, which can be varied by chemical means, Levapren® is also compatible with other polar polymers. It is, for example, an ideal plasticizer for the common plastic PVC, because it does not leach out.The polarity of EVM rubber results in excellent compatibility with polar fillers, such as silica. Finally, rub-ber materials with a percentage of highly polar Leva pren® display good bonding properties (see page 36).Apart from the VA content, chemists also have con-trol over the viscosity of the material. A low viscosity allows rubber products containing Levapren® to be injection molded or extruded at temperatures rang-ing from 180 to 200º C in a cost-efficient process that delivers reliable quality.

Fire-resistant and non-toxicLevapren® is suitable not only as an “enhancer” for PVC, but also as a substitute for the chlorine-con-taining plastic. In contrast to PVC, blends of nitrile rubber (NBR) and Levapren® are halogen-free and therefore a viable alternative for use in applications associated with a high fire risk, because they release no corrosive gases when burned. What’s more, blends of Levapren® with special fillers achieve outstanding flame retardance, meaning they do not burn readily and have a self-extinguishing effect. Blends of this kind can easily be extruded to make sheathing for electrical cables or thermal insulation. They are generating rising demand on the high-growth market for halogen-free, low-smoke cables for safety-sensitive products, such as household appliances, computers, solar energy systems and

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Levapren®

Master of versatilityAdaptable

Thanks to its versatility Levapren® serves as a material for a wide range of applications.

Blends based on Levapren® are also suitable for use as cable sheathing in fire risk areas owing to their flame-retardant properties.

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Let there be Lightw passengers on articulated

buses can now enjoy bright-ness in the previously dingy area of the gangway bellows. a few years ago, ContiTech designed a transparent variant to replace the usual opaque “accordion” between the front and rear sections of “bendy” buses. These translu-cent bellows are made of the evM rubber Levapren® from LanXeSS and meet all the requirements typical of daily operation – Uv rays, water, road salt, oil and stone chip-pings are no match for this tough material. What’s more, the elastic Levapren® is also extremely weather-resistant and can withstand tempera-tures ranging from minus 20

to plus 120º C. not even the constant bending and uneven road surfaces can wear out the Vitroflex® bellows from ContiTech, because – even with low filler content – the material boasts high strength values when subject to flexure. Last but by no means least, the Levapren®-based bellows also offer welcome optical effects. Thanks to the transparent material and a dirt-repellant surface, daylight doesn’t just shine through the bellows, a special refraction process ensures that it even has a brightening effect, thereby lighting up the previously dark interior, a factor that also increases safety. These translucent

bellows are not just ideal for articulated buses, they can also be implemented in trains and passenger walkways.

wind power plants, but also are highly sought-after in the foamed state as insulation for heating and air-conditioning system conduits and as damping elements and sealing components in highly fre-quented buildings, such as airports, hotels, subway stations, theaters and museums. They additionally find application in aircraft, railway and automotive engineering. But what makes this material, which has been manu-factured by LANXESS and its predecessor, Bayer, for the last 40 years, so extraordinary and versatile?EVM rubber has been a familiar material for some 60 years, but it was tricky to manufacture. The “medium-pressure method” used by LANXESS now supports cost-efficient production of Levapren® grades containing 40 to 90 percent vinyl acetate.

These EVM variations, synthesized by LANXESS in a special solvent, can be customized in terms of both their VA content and viscosity. Levapren® 450, for instance, contains 45 percent VA (indicated by the first two digits), which translates into very low viscos-ity and, in turn, easier processing.

popular enhancerAdaptable to any number of requirements, this versatile rubber can significantly improve the proper-ties of other polymers. In blends with thermoplastic polyurethanes, for example, just a low percentage of Levapren® gives a product good haptics and a matt surface, as is frequently required. Blends of PVC and nitrile rubber (NBR) are another example. Although they have proven useful in numerous branches of

LowSmoke® specialpurpose rubber for French railroad trains.

A brighter place in articulated buses thanks to bellows made of Levapren®.

The many kilometers of cables needed in an Airbus must be fire-resistant.

Levapren®

possible by the development of materials capable of withstanding a variety of adverse conditions, like heat- and media-resistant Levapren®. For example, the Audi A8 4.2 TDI and the Audi A8 6.0 with a twelve-cylinder engine are equipped under the hood and even in the crankcase with hoses sheathed in Levapren®, enabling them to withstand sustained temperatures of more than 160º C at a pressure of 4 bar. In the event of a fire, these hoses withstand the flames for at least two minutes even at a temperature of 800º C. Levapren® also provides a high level of safety in the sheathing of sensor lines in ABS antilock brake sys-tems. For good reason: these cables are in the direct vicinity of the engine, wheels and hot disk brakes, and therefore must withstand both intense heat of more than 160º C and biting cold of minus 40º C.

advantages in productionAnother decisive advantage of Levapren® relates to the production process: LANXESS uses special solvents for the polymerization of ethylene and vinyl acetate. As a result, polymerization yields a non-gel product that can be processed easily and cost-ef-fectively. For use in ABS lines, the material must be absolutely free of gel particles. Although small gel particles only have a negative impact on the surface appearance, larger ones would pose a real safety threat because they can cause tears in the insulation, thus leading to a short and ultimately to the failure of the entire antilock brake system, with potentially devastating consequences for the vehicle, the driver and other road users.Another advantage of Levapren® in ABS sensor lines is its high strength under flexural fatigue stress, as occurs under mechanical load in the wheel arches. Levapren® also is a reliable rubber material for

industry, they have been criticized by environmental-ists on account of their high chlorine content. In this case, Levapren® can replace the PVC. Blends of NBR and Levapren® are not only free of halogens, they also offer equivalent material properties and can be compounded without the fusion step.

vulcanization as usualWhen it comes to the optimum vulcanization of this polymer, all methods proven effective for crosslinking other polymers with a low double-bond content are effective for Levapren®, such as high-energy radiation or the use of peroxides. Levapren® can be vulcanized with organic peroxides under standard conditions, e.g. in presses, saturated steam or inert gases under pressure and at temperatures above 160º C. A wide range of tried-and-tested combinations of peroxides and activators can be used to produce the desired level of crosslinking and customize the ten-sile strength and elongation at break of a vulcanizate.Adaptability and diverse blending options – the dif-ferent Levapren® grades can be blended with one another as well as with plastics – give Levapren® access to a steady stream of new applications. As a reliable material for heat, oil and lubricant-resistant hoses that display no signs of aging thanks to their additional resistance to oxygen and ozone, as a component in effective seals and vibration dampers, or in floor coverings and cable sheathing that can save lives in the event of fire, this high-performance material from LANXESS comes into its own in all ap-plications that depend on uncompromising quality, a long service life and safety.Technical progress in automotive engineering, based on innovations such as ABS antilock brake systems, noise-reducing engine encapsulation and high-performance diesel engines, has been made

34 35

When night falls on a large-scale event, such as an open-air concert, sporting event, film shoot or trade show, or on a major construction site or rescue operation, an artificial moon sometimes is released 50 meters into the sky to supply non-glare light over an area of up to 800 me-ters in diameter. The glowing balloon produces something similar to twilight even from two kilometers away in any direction.Named HeliMax, this floating “light bulb” can measure up to 5.5 meters in diameter. The skin coated with Leva-pren® and filled with helium houses metal vapor lamps with an output of 16,000 watts. The balloon is tethered to an electrical cable. Larger models additionally are secured by a steel cable and

a power winch.The advantages of this “heav-enly” light source: the empty skin can easily be transport-ed to virtually any location, and its light does not blind spectators, drivers or rescue teams. The skin, coated with Levapren® from LanXeSS, is made by ContiTech; the complete luminous balloon sets are marketed under the brand name pOWerMOOn® by noelle Industrielle Umwelttechnik GmbH.

heLiMAx iLLuMinAtes

Flexible and heat-resistant

Nonglare light for a variety of events and applications.

... and provide reliable sealing even in the toughest of conditions, and virtually without aging .

Blends with the versatile synthetic rubber Levapren® give training shoe soles their cushioning effect ...

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automotive seals. One prominent example is the seal on the cylinder head cap of the ten-cylinder diesel engine used by Volkswagen’s subsidiary Audi in its top-of-the-range cars. The seal material is a rubber blend based on Levapren®, developed by automotive supplier SKF, that reliably withstands extremely high temperatures and lubricants.

Safe railroad trainsWhen it comes to passive safety on trains and buses, particular attention is paid to the fire behavior of the materials used in their construction. Engineers impose strict demands on rubber seals (e.g. engine housings), shock-absorbing elements (for effective and safe suspension-mounting of generators and engines) and insulating mats for floors, just to name a few components. The material, like the cabling,

should evolve virtually no toxic gases at all in the event of a fire and only a very low smoke density. What‘s more, it should be self-extinguishing. All these properties are fulfilled by the specialty rubber LowSmoke® 33-4, manufactured from Levapren® by the French elastomer specialist Interep and supplied to customers such as Alstom, a railroad equipment manufacturer.Flame-retardant floor coverings and conveyor belts are a high priority in airports. Levapren® floor cover-ings meet all the requirements of fire protection class B1 to DIN 4102 and offer further advantages compared to other rubber materials: thanks to the material’s saturated molecular backbone, they are extremely weather resistant, and the high polarity ensures good bonding properties.

A tight hoLdClosely related in chemical terms to the synthetic rubber Levapren® is the adhe-sive raw material Levamelt®. Thanks to its versatility and compatibility, this ethylene-vinyl acetate copolymer is rapidly advancing the development of customized adhesive solutions. Levamelt® adhesive grades offer a number of advantages. By selecting the right one, it is possible, for example, to remove an adhesive, or a film coated with the adhesive, without leaving behind any residue. For this reason, car-makers are increasingly turning to protective films made from Levamelt® to protect new vehicles against scratching during transport from the factory. In the past, this protection was provided by wax, which the dealer then had to wash off using exces-sive amounts of solvent. In contrast, a film containing Levamelt® can be removed quickly and completely.Levamelt® films are also used to protect mobile telephone displays, computer screens

and watch faces before these are used for the first time.Other fields of application for Levamelt® include printable stickers on windows for advertising purposes, which can easily be re-moved and reused again once the campaign has finished.With Levamelt® formulations, LanXeSS has also solved the problem of increased tensile bond or peel strength due to aging, which is observed in many adhesives.The following statistic illustrates the immense commercial potential of Levamelt®: some 12.7 million metric tons of polymers were used worldwide for adhesives in 2006. In other words, the market is even larger than that for technical rubber products, a market which is served successfully by the LanXeSS Technical rubber products business unit with its high-performance rubber products.

Cables and floor coverings in heavi ly frequented buil dings must be noncombustible.

Levapren®

The chemical plant in Dormagen, Germany, is one place where LANXESS produces Levapren®.

Levamelt®-coated film protects computer screens.

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dicate directly in the name the saturated backbone of these ethylene-vinyl acetate copolymers. They go by the designation “ethylene-vinyl acetate rubber with a methylene main chain” or simply: Levapren®.

Wind power plantsThe increased use of wind energy around the world, generated by expansive, primarily offshore fields of wind turbines, has opened up a dynamic market for Levapren®. The electric power generated by a turbine in the nacelle of the system must be trans-ported by a trailing cable to the base of the tower and from there to other locations. The cable hangs freely in the shaft of the tower, which is frequently more than 100 meters high. Required to conduct up to 36,000 volts, the cable must not only be fire-resis-tant and withstand operating temperatures of 90º C, in the event of a short it must also temporarily resist 200º C without failing and function reliably even at minus 40º C. These extreme requirements are met by an outer insulating sheath made from a special grade of Levapren® developed specifically for this application and processed, for example, by cable manufacturer Pirelli Prysmian. In the brand name “TECHWIND<H>”, the “H” indicates that the outer cable sheath contains no halogens.

Terms and definitionsFor a layperson, the numerous designations for ethylene-vinyl acetate copolymers can be confus-ing: EVAc, EVA, E/VA, EVM. All these abbreviations essentially refer to the same thing, with only minor differences. The abbreviation EVA usually stands for “classical” ethylene-vinyl acetate copolymers with a low vinyl acetate content. The abbreviation EVAc and the short-lived designation E/VA, although no longer standard today, are still used in some cases. Accord-ing to ISO 1043-1: 1987, thermoplastic variations of the material are to be labeled E/VAC. The abbre-viation EVM was introduced by employees of what is now LANXESS based on the widespread rubber nomenclature defined in ISO 1629: 1995 (E), to in-

Power cables

The trailing cable in a wind power plant transports the electricity from the transformer in the nacelle through the 100meterhigh tower to the control cabinet at the base. At the top, about 18 meters of cable is freely suspended in the tower, before being looped to the inside wall where it is firmly fixed next to the ladder and taken down to the base. The cable hangs freely below the nacelle, because the turbine constantly realigns itself to make optimal use of the wind. The cable has to follow these movements and must be able to twist four times around its own axis – to both the right and the left – over the defined length. The torsional flexibility that is required for the fine energyconducting wires and earth conductor (see crosssection above) is achieved by a special form of stranding; a special rubber compound based on Levapren® ensures that the rubber sheathing has the necessary flexibility and dynamic stability.

In wind power plants Levapren® protects electricity cables.

Pulling, pressing, tearingLong before new rubber compounds are used on an industrial scale, they undergo numerous costly and time-consuming tests at LANXESS’s polymer testing department in Leverkusen. These enable the Tech-nical Rubber Products business unit to investigate and document the desired properties of the different compounds – also frequently on behalf of customers who are developing new rubber compounds them-selves. The test program includes loading tests at temperatures ranging from -50° C to 200° C, highly dynamic vibration tests, which supply information about molecular structures, and tensile tests, which document the elongation at break of elastomers and compounds.

Polymer TesTing

38

From rubber to elastomerWhen crosslinking rubber, chains of molecules are chemically bonded with each other. As a result of this process, the highly viscose molten mass of rubber undergoes an irreversible transforma-tion, becoming an elastic, dimensionally stable elas-tomer. The parameters of crosslinking – principally time, pressure and tem-perature – are measured using a curemeter.

New compounds are first churned and kneaded in spe-cial apparatus in order to spread the individual compo-nents of the compound evenly in the rubber mass. Only then are they vulcanized in the oven. Here are some examples of the wide variety of test methods used.

39

Selection of ingredientsDepending on the application, certain polymers are mixed together with selected compo-nents such as fillers, plasticiz-ers, crosslinking agents and antioxidants, in line with a precisely defined recipe. This composition, which is based on many years of experience, means that the end product will later display the desired properties.

A look inside the material Highly dynamic stress tests shed light on the molecular struc-tures, revealing, for example, the type and length of the poly-mer chains.

3

To the limitBecause it is an important characteristic of the different types of rubber, the behavior of rubber samples at low temperatures is tested – in ex-treme cases right down to a temperature where the rubber sets like glass.

40 4140 41

High-frequency testOn the one hand, dynamic-mechanical characterization serves to optimize the pro-cessing properties of rubber com pounds, while on the other hand it enables the mechanical properties of end products to be ascertained.

Polymer TesTing

Test specimens The test specimens, which are vulcanized in special molds, are used to measure parameters such as tear strength, elasticity, hardness, aging and compressive deformation. This sheds light on how the material will behave when it is later used in elastomer components.

Elongation test A rubber rod, fitted with reflectors, undergoes a tensile test. During the elongation process, lamps trace the elonga-tion of the test object until it tears, using the reflectors positioned at two points on the object. The data regarding the elongation and the force used are important para-meters for the rubber industry.

40 4140 41

It’s all in the mix New mixtures – as the name suggests – must first be properly milled and kneaded, so that the components of the mixture are dispersed evenly in the mass of rubber. The LANXESS labora-tory has various items of equip-ment for use in this process: internal mixers that can hold volumes from 1.5 to 90 liters, and steel rollers that run against each another at variable speeds and generate high shear forces.

Shaping up well Extruder for rubber profiles: The compound strips are shaped into profiles by the extruder and then vulcanized by microwaves in the heat-ing section.

SEALING • DAMPING • TRANSPORTING

DAMPINGSEALING

TRANSPORTING

The unseen all-roundersTechnical rubber products perform vital tasks in machines, buildings, vehicles and almost all technical devices. With-out attracting attention, they effectively keep roofs and machines air and watertight, absorb vibrations in vehicles or bridges and, in the form of bands, belts, hoses or cable sheathing, transport a huge variety of solids and liquids, as well as energy.

they doe not generally catch our eye. Before synthetic rubber was invented by researchers from the com-pany then known as Friedrich Bayer, and later devel-oped to market maturity, engineers largely had to put up with all sorts of unreliable materials when building machines, and schedule changes of seals at frequent intervals. Sealing rings for pump tappets were manu-factured from a combination of leather and metal, with cork and felt being available as alternatives. The first shaft seals, known in German as “Simmer-ringe” after their inventor Walther Simmer and used to seal the bearings in shafts and axles, were manu-factured by the Freudenberg company in 1929. Sim-mer’s radial shaft seals initially still consisted of pieces of leather and metal. However, it was not long before these materials were combined with synthetic rubber, and in 1942 Freudenberg produced the first rubber-ized shaft seals, which had a Perbunan® sealing lip.Further developments in synthetic rubbers now mean that radial shaft seals can be designed for almost all requirements, with properties such as excellent compatibility in almost all media and minimal friction with only marginal wear. As a result, shaft seals are now available for motors, drives, axles with articulated shafts, wheel hubs and axle journals, as well as for many other fields of use, even where these mean ex-treme conditions.These are accompanied by diverse sealing systems for pumps, cylinder head and cylinder head cover gaskets in motor vehicles and axle sleeves along with important blowout preventers in drilling rigs, which can prevent an explosive discharge of crude oil and crude gas (see also page 48). Depending on the load placed on them and the use to which they are put, seals are based on suitably adapted elastomers, such as Therban®, which is re-sistant to heat, oil and ozone, or Therban® AT, a low-viscosity type of HNBR rubber. The transparent plastic roof tiles on the Chinese Olympic Stadia in Tianjin and Shenyang are jointed with the Buna EP 6470® and Buna EP T 9650® rubbers respectively, as these sealing materials are particularly resistant to weather-ing, ozone and UV rays (see also page 46 ff.).

Damping…Without the calming power of rubber shock absorbers, travel by car or rail would not just be highly uncomfort-able – the vehicles would quickly break up as a result of the vibrations in their assemblies and the impacts caused by uneven places in the road or track. From the tires and the suspension to the engine mounting and the damping of shaft vibrations, cushioning, damp-ing and decoupling rubber parts – often paired with hydraulic systems and air springs – are used to ensure quiet running and the stability of the vehicle.Yet also below the car’s tires – on bridges – high-per-formance rubber cushions deaden the oscillations

45

If the tap does not drip, this is thanks to a good rub-ber seal. If the car’s engine does not judder, this is thanks to good rubber shock absorbers. After landing, when the luggage safely arrives on the carousel in the airport’s arrival hall, this is thanks to transport on a non-slip band coated with rubber. We could continue to list an almost inexhaustible number of examples of the use of synthetic rubber in almost all areas of life – whether in the home, in the office, in the factory, while traveling, working underground in a mine or on the high seas in ships and on drilling platforms, in construction above and below ground, in aerospace or in medical technology, in engineering, safety tech-nology or chemistry. To obtain an overview of the wide variety of applica-tions and functions for which the numerous syntheti-cally manufactured types of rubber, with their diverse properties, are suitable, it is helpful to divide these ap-plications by the types of task performed by products made from one or more types of rubber: seals, shock absorbers (and springs) and transport systems, with insulating material for electrical lines or for the insula-tion of pipes carrying cold or hot media also being allocated to the area of transport. After all, something is flowing or moving under the insulation – be it elec-tricity, water, steam, coolant...

Sealing…In devices, in construction, in means of transport – and not least in the form of protective clothing for divers or for those dealing with hazardous substances – seals play a role that is no less vital for the fact that

Rubber for all occasions

SEALING • DAMPING • TRANSPORTING

In container vessels and cruise ships, couplings containing Therban® ab-sorb dangerous vibrations from the drive shaft.

Hoses with EPDM cladding and integrated heating wires for SCR technology, designed to reduce the nitrogen oxides produced by diesel vehicles.

High-performance toothed belts are replacing the chain drive on motor bikes.

and vibrations caused by traffic or by the wind. Hardly any bridge constructions can function without vibra-tion dampers and elastic buffers between the contact points of the weight-bearing parts and the road (see page 54 ff.).Moreover, in areas where there is a high risk of earthquakes, such as Japan, California or southern Europe, whole skyscrapers and even nuclear power stations are built on elastic foundations, which absorb the worst of the impact in the event of an earthquake and thereby prevent the building from collapsing. What is more, wind farms would not last long without elastic bearings and oscillation dampers.In many cases, the manufacturers of shock absorbers make use of the varying constructions and properties of natural rubber as a base material. However, bellows, shock absorbers, bearings and oscillation dampers of-ten have to function in an environment with aggressive media and in extreme temperatures, for example in automobiles, in rail vehicles or in the open air. In such cases, there is a need for synthetic polymers whose properties can be adapted by chemists so that they suit the usage conditions and external circumstances exactly. In this context, hydrogenated nitrile rubbers such as Therban®, or chloroprene rubbers such as Baypren®, have proven to be reliable materials.

Transporting...Whether wheels, rollers, bands or hoses – when it comes to transporting people and materials, almost nothing can be achieved without rubber. Cars run on tires made of rubber compounds, containers full of goods are con-veyed into the holds of airplanes on hard rubber rollers, conveyor belts coated with rubber transport the roughest stone from mines and millions of feather-light letters in the post office distribution centers or convey people from one gate to the next in huge airport terminals, while also transporting their luggage to the airplane.

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Safer transport

Rubber-coated conveyor belts bring luggage into the arrivals hall on the carousel, without the risk of items slipping off.

Air springs protect the driver and load from se-vere jolts, even in heavily laden trucks.

When it comes to driving things forward, the many and varied forms of belts – drive belts, v-belts, toothed belts or ribbed v-belts – are absolutely essential for power transmission, with only toothed wheels and chains being capable of similar performance. In cars, belts drive the lights, pumps and cooling systems, in some motorbikes they are replacing the chain, in printing presses, in mines or in factories they can be relied upon to function as the driving force, just as they do in fairground carousels.This is another field of use where the high-perfor-mance rubber Therban® has proved its worth.When it is necessary to transport water, for example to put out fires or water gardens, to transport fuel, oil, brake fluid or hydraulic oils within vehicles or ma-chines, to move cement on building sites or to convey cold and hot media in an insulated line, rubber or rubber-coated hoses offer a simply infinite number of possible applications: Flexible in very small spaces, in the heat under the hoods of cars, stretched out and fire-proof in large-scale building complexes – for example as thermal insulation hoses for air-condition-ing or heating systems – resistant to cold in the harsh climate of crude oil production in Arctic regions or resistant to hard physical stresses when transporting sharp-edged bulk goods – rubber and rubber-coated hoses can be adapted to almost any environment, as there is a suitable synthetic material such as Buna® EP, Baypren®, Therban®, Therban® AT, Krylene® or Krynol® no matter the task or the demands placed on the hose. The following sections highlight the almost infinite versatility of technical rubber cit-ing everyday and special applications.

Under the hood, hoses must cope with heat and aggressive media.

In mines, rubberized conveyor belts are used to transport even the hardest pieces of rock.

fuel, oil and coolant – as with the cylinder head cover gasket in a car engine – seals made from HNBR or EVM rubber offer a long service life in many cases. Automotive shock absorbers and gas-operated struts also require oil- and temperature-resistant rubber seals, however, while axle boots made from the chlo-roprene rubber Baypren® or from Therban® are used to seal drive shafts. These examples give just a taste of the many applications for seals in the automotive sector – without even touching on obvious uses such as door and window seals made from EPDM rubber such as Buna® EP. It’s hardly surprising that around 39 percent of the world’s annual EPDM production of around 350,000 to 400,000 metric tons goes into the manufacture of seals.

Reliable sealing elements Where rubber seals are expected to perform reli-ably under extreme conditions – in heat and cold, in contact with aggressive media such as oil, petrol or brake fluid, under exposure to ozone and under heavy mechanical loads – then elastomeric materials are an absolute essential. Encompassing acrylonitrile-butadi-ene rubbers (NBR) such as Perbunan®, Krynac® and Baymod® N, hydrogenated nitrile rubbers (HNBR) such as Therban® and the low-viscosity Therban® AT, ethyl-ene-propylene-diene rubbers such as Buna® EP and ethylene-vinyl acetate rubbers such as Levamelt® and Levapren®, LANXESS high-performance rubbers are the ideal sealing material for applications demanding maximum reliability. For example, where heat resis-tance is an absolute priority in addition to resistance to

Sealing rings perform reli-able functions in expensive watches and in nuclear power stations.

SEALING

Going around

The TIANJIN CENTER OLYMPIC STADIUM was already host in fall 2007 to the FIFA Women’s World Cup. Buna® EP T 6470 is used as a sealing mate-rial in its transparent roof.

SEALING

47

Safely sealed

The transparent roof structure of SHENYANG OLYMPIC STADIUM comprises 2,000 square meters of polycarbonate sheeting. Profiles made of Buna® EP T 9650 seal the joints.

such as UV radiation and ozone gave it the edge. The Shenyang stadium, one of five venues for the soccer competition, holds 60,000 spectators. From a roof in the air to a hole in the ground: anyone wanting to create a pond in their garden must seal the hole in a proper manner to prevent the water from seeping away. Liners made from plastic or simple rub-ber grades age very quickly, however, on exposure to UV radiation, ozone and temperature variations – they become brittle and lose their sealing capacity. The same does not apply to liners made from EPDM rub-ber: they withstand environmental influences, remain supple for a very long time and are environmentally friendly because they do not contain plasticizers. This is a case for Buna® EP.

Seals in drilling rigsTherban® seals also deliver sterling service in oil pro-duction, ensuring high safety standards. Manufacturers of blowout preventers, for example – powerful seals which prevent oil or gas from escaping from the bore-hole in the event of a sudden rise in pressure – back the low-viscosity high-performance rubber Therban® AT, since this material is not only immune to oil, high temperatures and the fluids used in oil production but also ensures an intimate metal/rubber bond.The vital service performed by seals is not limited to large-scale industrial use, however. Precision engi-neering tools and scientific instruments also need

In pump engineering too, seals have a central role to play: for example, a leading German manufacturer of eccentric screw pumps uses the hydrogenated nitrile rubber Therban® AT for the rubber sleeve – known as the stator – in which the screw-shaped steel rotor turns. This material is resistant to the high pressure, strong frictional forces and high temperatures that accompany the use of these pumps.

Radical roofing structuresThe construction industry too relies on seals, from profile seals made from ethylene-propylene rubber (EPDM) for windows and doors, joint-sealing materi-als or rubber sheets for covering flat roofs to sealing profiles for roofing structures built from plastic sheets. Prominent examples include the roofs for two new sports arenas in China built for the 2008 Olympics: the roof on the Tianjin Olympic Center Stadium (left) uses Buna® EP T 6470 as a sealing material between the polycarbonate sheets. This EPDM sealing profile was chosen because of its weathering and ozone resistance along with its dimensional stability, even under substantial temperature variations. The futuris-tic roof of the Shenyang Olympic Stadium (above) is also constructed from multiple transparent polycar-bonate sheets. They have to let through sufficient light to enable the natural turf to grow. Buna® EP T 9650 profiles were used to seal the joints. In this case too, the material’s resistance to weathering influences

Plate heat exchanger with up to one kilometer of sealing material made of Therban®.

48 49

SEALING

w

At many connecting points in drilling systems, different media have to be sealed off from each other. Only high-performance rubbers that are resistant to oil, gases and aggressive drilling fluids, can withstand the high temperatures at depths of 5,000 meters and above and are not worn away rapidly by the rough drillings are considered for this application.Rubber seals can be found in many vital areas of drilling rigs and oil platforms, such as in the drilling fluid pumps and diesel motors for energy generation, as well as in the rotary table system and in the drilling rig itself. In addition, there are hoses for remov-ing the cuttings and transporting the oil that has been extracted to the next stage. If thick stone poses a barrier to opening up an oilfield, or if the plan is to drill into the oleiferous layer from the side, the drilling teams often make use of a clever trick. In order to bypass the obstacle or to ap-proach a deposit from the side rather than from above, the oil producers do not use a drilling rig with a rigid steel rod, but rather approach the deposit through boreholes “round the corner”. To achieve this they make use of a stator-ro-tor system which is based on the opposite of the operating principle for a Moineau or PCP pump (Progressive Cavity Pump) and, thanks to its small dimensions, permits the drill head to navigate through the substrate. Here the drill head is driven by a metallic rotor located in a rubber stator. The rotor and the drill head begin to move as soon as fluid under high pressure is pressed through the helical cavity between the stator and the rotor. Turning the rotor in the opposite direction means that even extremely vis-cous crude oil can be brought to the surface using hot steam.The rubber used for the stator does not only need to be resistant to oil, but must also withstand extreme stresses and high temperatures. The use of Therban® AT means that the production of these stators can be further optimized. The ease of flow of this HNBR elastomer enables the molds that are used to manufacture these stators to be filled more rapidly and reliably – with the outcome being a very homogenous vulcani-zate that withstands the stresses placed on it for a significantly longer period of time.

RUBBER COMPONENTS IN CRUDE OIL TRANSPORT

Left: Rotor and sta-tor-rotor system with which rock contain-ing oil can also be drilled into from the side.

Right: Blowout preventers seal the borehole in the event of excess pressure.

1 Drilling rig 2 Hose for drilling fluid 3 Machines4 Drilling fluid pump5 Cuttings6 Casings7 Drilling fluid 8 Drill head9 Blowout preventer

Rotary table

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helps to reduce the amount of material used. In addi-tion, the low viscosity of Therban® AT allows the filler content of the formulation to be increased without a significant rise in the viscosity of the blend; this also leads to an improved long-term compression set (see page 52). The Therban® AT seals applied by injection molding are not only cheaper to produce but also improve the quality and service life of the two-compo-nent part.

Applications under the bonnetBy contrast, automotive component supplier SKF Sealing Solutions GmbH relies on a blend based on the EVM rubber Levapren® for the patented design of the cylinder head cover for a number of Volkswagen diesel models – including the 10-cylinder diesel ver-sion of the high-end Phaeton model and the Touareg

seals that are matched exactly to their intended function. Elastomeric O-rings can even be found in top-quality Swiss watches: tiny ones measuring just 0.7 x 0.2 millimeters. By contrast, their big broth-ers – which are used in space telescopes or nuclear reactors, for example – can have internal diameters of over ten meters. O-rings, which owe their name to their circular cross-section, are usually made from NBR rubber and certainly have the most diverse range of applications of any seals. Owing to their relatively simple shape, they are easy to manufacture on an industrial scale. Most are used for static sealing applications, in water taps for instance.

Oil sump made from two componentsLANXESS made an important advance when it developed a cost-effective production method for complex plastic parts comprising a rigid and a flex-ible component. In order to produce an oil sump with an integrated seal from the two materials in a single production step, the raw materials had to be very carefully matched to one another. The rubber and plastics experts achieved this using the polyam-ide Durethan® and a special variant of HNBR rubber, Therban® AT. With a Mooney viscosity of 39, it is exceptionally free-flowing and pours easily, so it is perfect for injection molding. In two-component injection molding, the rubber compound can be removed from the injection mold-ing machine at low pressure, and the gasket can be extruded in a rotary-table injection molding machine immediately after production of the glass fiber-rein-forced Durethan® shell. This two-component concept saves money, speeds up the production process and

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Water-tight

Tarpaulins such as these reliably seal the bases of fishponds.

When farmer Reimer Peters stumbled not upon water but on a noxious-smelling form of sand when digging a well near Hemming-stedt in Schleswig-Hol-stein in North Germany in 1856, geologist Dr. Ludwig Meyn’s curios-ity was aroused. He

was convinced that this foul-smelling substance was crude oil, and he be-gan digging what was almost certainly the world’s first exploratory well for liquid oil. In this case, he found only bituminous sand, but this marked the start of something big. Just two years later, oil began to bubble from the first manmade oil wells - in the town of Wietze in Lower Saxony and in Titusville, Pennsyl-vania. While the discovery in the Lüneburg Heath attracted little atten-

tion to begin with - oil fever did not hit Wietze until 1899, when a borehole drilled down to a depth of 270 meters brought a flow of crude oil to the surface - the Titusville findings are regarded as the true beginnings of the oil industry.

In his attempts to find crude oil, Ed-win Laurentine Drake, general agent for the Seneca Oil Company of Con-necticut, used a drilling tower similar to one he had seen at salt extraction sites near Pittsburgh. First of all he drove pipes into the ground and then, when he hit subsoil at a depth of 32 feet (ten meters), he lowered a drill rig, assembled on site, through the pipe and bored through the bedrock using steam. After a long and painstaking opera-tion, the tip of the drill hit a crack at a depth of 69.5 feet (21 meters) and sank. The next morning, drillmaster Smith spotted oil rising through the borehole. Drake was soon extracting 1,500 liters a day from this borehole. Before long there were around 2,000 bore-holes in north-western Pennsylvania, from which almost two-thirds of the entire world production was being

pumped at one time. Vital to the success of Drake’s early attempts was his idea of using pipes to protect the borehole against penetrating groundwater and falling rocks. Such feed pipes (casings) are generally now made from durable and seamlessly rolled steel pipes with high-pressure-resistant threaded joints. These prevent the walls of the borehole from collapsing and also stop oil or gas from escaping into the rock of the borehole. The drilling fluid, which is introduced via the drill rods, is driven up between the casing and the drill rods to remove the fragments of rock from the bottom of the hole.

PIONEERS OF OIL PRODUCTION

Garden pond with secure base comprising a rubber tarpaulin.

Drilling tower of Seneca Oil Com-pany in Titusville, Pennsylvania.

Oil explorer Edwin L. Drake.

Oil pan with a sprayed-on Therban® AT seal.

50 51

MOBILITÄT

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racy, drop after drop. Once again, Perbunan® from LANXESS can be found in these high-tech products, such as those manufactured by ContiTech Elastomer-Beschichtungen GmbH.

A kilometer-long sealPlate heat exchangers, which are used to cool or heat fluids, also place unusual demands on the sealing material. Effective separation of the media circulat-ing through these units is absolutely critical. The plates must be sealed to the outside and between the media. In addition to tried-and-tested NBR rubber grades such as Perbunan®, Therban® AT, the low-vis-cosity variant of the high-performance HNBR rubber Therban®, makes a very effective sealing material here, too. The good compression set and excellent chemical and aging resistance of the vulcanizates are further enhanced by their exceptionally good homogeneity – an important factor in the long-term reliability of the installation.To make the transfer of heat as effective as possible, plate heat exchangers can be very large. The surface area of the individual plates between which the media flow can measure ten square meters or more. A large heat exchanger with over 1,000 square meters of exchange surfaces will therefore require more than a kilometer of sealing material. Depending on the place of use and the media to be cooled, these seals are often subject to considerable loads: in the chemical industry the material can be attacked by aggressive reaction products and solvents; in addition, high oper-

sport utility vehicle (SUV). The aluminum cylinder head cover protects the valve gear, fuel injection system and cooling lines from moisture and dirt from outside while at the same time protecting the environ-ment from escaping lubricants and vapors. The cover must therefore be hermetically sealed, and at the same time the rubber seal must be resistant to the high engine temperatures and to oil and other aggres-sive fluids. Finally, the Levapren® seal must retain its integrity for the lifetime of the engine. The ethylene-vi-nyl acetate rubber Levapren® offers all these proper-ties: it does not swell in oil, is resistant to coolants and combines well with fillers, it can withstand continuous temperatures of over 170° C – and transient peaks of over 200° C – and remains flexible even at tempera-tures below freezing. Unlike the injection-molded Therban® AT seal on the oil sump, the cylinder head cover seal on VW models is not permanently connected to the metal compo-nent, allowing it to be replaced quickly if necessary.Where liquid or gaseous substances need to be separated in a reliable manner, membranes are the ideal solution. In pressure regulators, for example, Perbunan®-coated membranes control vibrations to ensure precision fuel injection into the cylinder of a car engine. They also damp vibrations in the car’s fuel system, while at the same time reducing hydro-carbon emissions. Elastomer-coated membranes are used in medical engineering, too: without their help, infusion pumps could not deliver vital fluids with absolute accu-

Reliability

Axle boots also have to remain tight when the brakes are scorching hot.

Reliable seals and ad-hesives have long been absolutely essential for bodymaking in the auto-motive industry.

VW Phaeton V10 with cylinder head cover gas-ket made of Levapren®.

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piston pumps are NBR or HNBR rubber grades such as Perbunan® or Therban®. Where there is a need to convey particularly abrasive or highly viscous fluids, engineers often choose ec-centric screw pumps. In this design the driven, screw-shaped rotor rotates eccentrically about its axis inside a housing, known as the stator, whose threaded inner wall is made from rubber. Thanks to the specially matched shape of the rotor and stator, sealed cavities form between the two parts and advance in an axial direction as the rotor turns, conveying the medium contained in these cavities to the head of the pump. The edges of the screw press firmly against the rub-ber wall of the stator so that the medium cannot es-cape. The volume of these cavities remains constant during the pumping operation, so the transported medium is exposed to only minor loading or crushing. The same cannot be said of the stator, whose flexible inner wall has to withstand a variety of dynamic and chemical loads, which only a few rubber grades are capable of resisting: the high pressure with which the rotor presses against the stator, together with the permanent churning action during pumping, and in many cases also heat, sand and sharp pieces of rock

ating temperatures can often cause traditional rubber grades to become brittle very quickly. Dirt, abrasive decomposition products and calcification can also act on the seals. They must therefore also be able to with-stand strong frictional forces. Since the presence of dirt between the individual plates, which are packed closely together, can restrict the flow of media, or even block it altogether, plate heat exchangers have to be flushed at regular intervals with acid-containing solutions. In order not to interfere with this proce-dure, the seals must not be glued together but must instead be self-adhesive and easy to remove. This de-mands excellent mechanical properties on the part of the material; thanks to its narrow molecular distribu-tion, Therban® AT can satisfy these requirements even over long service periods. What’s more, in sealing applications, high filler contents allow compression set values to be improved to new levels.

Pumps with rubberized insertsHigh-performance rubber seals are a vital component of many types of pump, too. In rotary piston pumps, for example, the tips of the intermeshing rotary pistons are made from rubber, which is bonded to the metal. The inside of the pump casing is also sealed with rubber so that the piston and wall fit together tightly. In this way the medium is conveyed by the two- or three-bladed rotors into the compression chamber by displacement, with no need for valves. Since the fluids being conveyed often include sandy sludges or other abrasive media, the rubber used as the sealing material must have a high abrasion resistance as well as being resistant to oil and high temperatures. That is why the materials of choice for manufacturers of rotary

Keeping things tight

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When laid out flat on the floor, the product measures eight times 26 me-ters. It is made from polyamide fabric with an outer coating that is resistant to weather, ozone and aging, as well as an inner coating that is resistant to fuel. When filled with petrol, kerosene or diesel fuel, it curves two meters into the air and can hold 300,000 liters of liquid. The tire and rubber manufacturer Continental produces folding containers of this size for such customers as the German army, but also for use in disaster and environ-mental protection. However, it is not just their huge scale that makes the flexible containers made from coated fabric so impressive. They also serve as light-weight fuel tanks in airplanes, as impact-resistant containers in helicopters, as self-sealing containers in armored limousines – and even as fuel tanks in Formula 1 racing cars. In order to satisfy the highest safety standards, they have to be able to withstand extremely high stresses

and be extremely air and water-tight. In addition, they should be as light and adaptable as pos-sible, so that they fill the available space in the optimal manner. The flexible light-weight containers – often having walls only 0.7 mm thick – are frequently coated with NBR rubber such as Baymod® N or Perbunan® and are also used for transport or storage or to collect a range of fluids. For example, when tests have to be carried out at a gas station with underground tanks that are full or partially full, the fuel can be transferred to one of these flexible containers and stored for the interim period, until the inspection or the neces-sary repair work on the tank is completed.

ThICK CONTAINERS ThAT GUARANTEE SAFETy

Flexible tank for gaso-line, diesel and other liquids.

SEALING

In pumps of varying de-sign and function – from rotary piston pumps…

... to eccentric screw pumps – rubber seals made of high-quality rub-ber are absolutely vital.

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edged solid components take their toll on the tubes of peristaltic pumps. That is why rubber grades based on acrylonitrile-butadiene rubber, such as Perbunan® or – for hot materials – Therban®, tend to be used as the rubber material.

Fire-resistant cable strandsInsulating materials for power cables can also be classed under the broad heading of seals, since they form an effective protective layer around the current-carrying copper wires. In many sectors, however, the insulating material not only has to protect against direct contact with the current-carrying core but in the event of a fire must also be flame-retardant and release no toxic gases. This is especially important where power cables are used in high-traffic buildings such as railway stations, airports, hospitals, theaters and museums housing valuable artworks, on ships – and in wind turbines. In all these situations, halogen-containing cable sheathing would be inappropriate, since it releases toxic gases in a fire. For that reason, when safety is an absolute priority cable manufactur-ers tend to opt for the EVM rubber Levapren®. This elastomer is not only halogen-free but also has excel-lent oil, ozone, UV and weathering resistance, making it suitable for use at sea as well. In addition, the low-viscosity EVM rubber can be supplemented with large amounts of fire-retardant fillers such as aluminum hydroxide without any difficulty. That is one reason why Vestas, the world’s leading manufacturer of wind turbines, has chosen Pirelli cables sheathed in a specially adapted Levapren® for its state-of-the-art V90-3.0MW wind turbines. In addition to flame retardance, resistance to harmful en-vironmental influences and unrestricted functional reli-ability in a temperature range from -40° C to +90° C (operating temperature) – with resistance to transient peaks of up to 200° C – this material also offers high elasticity and deformation resistance. This is important because the ten-centimeter-thick power cables sus-pended from the transformer in the nacelle turn as the wind direction changes and must therefore be able to withstand any damage (see also box on page 37).

Impermeable work wear and sports gearWhen it comes to protecting workers handling oil, fuels and other hazardous substances, manufacturers of protective clothing such as rubber boots, gloves and technical fabrics for protective suits depend upon reliably oil-resistant NBR rubber grades such as Perbunan®, Krynac® and Baymod® N or SBR rubber such as Krylene® or Krynol®. The soles of firefighting, construction and safety boots are often made from SBR rubber or the XNBR rubber Krynac® X, which is resistant to oil, acids and alkalis as well as being non-slip and abrasion-resistant.Technical fabrics for protective clothing generally

and – when used in oil production for example – ag-gressive chemicals and oil.A simple nitrile rubber will not survive such condi-tions for very long. By contrast, a special-purpose rubber based on the LANXESS rubber Therban® in its Advanced Technology variant will. The new Therban® AT grades make the production of eccentric screw pumps much easier. The extremely low Mooney vis-cosity of around 39 means that most of the solvents that were previously needed for manufacturing the stators can be dispensed with. This has the added benefit of improving the adhesion of the rubber to the metal of the sleeve.In the case of large stators measuring up to six me-ters in length, whose inner walls consist of umpteen kilograms of rubber, the low solvent requirement of Therban® AT also improves the weldability of the stator sections. The hydrogenated nitrile rubber from the new Therban® AT family has already proved its worth in eccentric screw pumps manufactured by Kächele in the town of Kirchheim unter Teck in the south of Germany.Peristaltic pumps, which convey materials by progres-sively squeezing them through a tube, need a rugged, impermeable tube. This tube is clamped by means of rollers or sliding pads, which rotate on a rotor. As the rotor rotates, the clamping point moves along the tube, driving the material forward. Pumps of this type are used in various configurations, for example as blood pumps in dialysis machines and in windscreen washer systems for cars, and also as concrete pumps. The powerful churning and aggressive friction that occur when the pumps are used for transporting media with relatively large and in some cases sharp-

When elastomers and rubber are placed un-der pressure, they become deformed accord-ing to their elasticity. If there is a decrease in pressure, they relax and, ideally, resume their original shape. Ideally, since over the course of time, when subjected to high levels of mechanical stress over long periods and to high temperatures and the effects of UV-rays, oxygen and ozone, elastomers lose at least part of their elasticity and never fully resume their original shape. Experts refer to the difference between their original form and their limited recovery as “compression set”. If this continues, seals and ground plates made of rubber, for example, become ineffective. It is therefore important to determine the exact compression set prior to using an elastomer. For this purpose, cylin-drical test specimens are generally deformed by 25 percent and stored for 72 hours at room temperature. The sample is then relaxed and the residual strain is measured after 30 minutes. The difference between original height and residual height is speci-fied as compression set as a percentage. The compression set can also be determined at

higher temperatures. A high compression set in samples that are in excellent condition acts, among other things, as an indicator of insufficient vulcanization of the elastomer. In the case of old samples, oxidative aging brings about a steady increase in compres-sion set.

hARD UNDER PRESSURE

The safety factor

Rubber samples placed under pressure in order to determine the compression set.

In dialysis machines the circulation is regulated by membranes coated with Perbunan®.

Without reliable rubber seals, laundries would often stand under water.

SEALING

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tive clothing. Wetsuits made from fully uncoated rubber are also available. They are more vulner-able to damage but are very flexible. Suits made from this type of material therefore fit more closely to the skin, keeping out water more effectively and allowing much more freedom of movement than fabric-coated material.

incorporate highly resistant media-tight barrier layers made from a combination of elastomeric composite materials and an integral ultra-thin polymer layer. This protects wearers of suits made from such material from hazardous substances such as chlorine, chlori-nated hydrocarbons or ammonia and is resistant to acids, alkalis and aggressive chemicals. The flexible protective layer often contains a butyl or NBR rubber (Krynac®, Perbunan®, Baymod® N). Worn with protec-tive gloves and boots made from NBR or SBR rubber, this whole-body protective clothing is suitable for both civil and military use. Since Baypren® too is highly resistant to chemicals, oil and sunlight, it is often used to make chemical-resistant protective gloves.

Thermal insulation for diversWhen it comes to thermal insulation in cold water, chlorobutadiene rubber (CR) such as Baypren® is the number one choice. The foamed mate-rial contains countless tiny, evenly distributed air bubbles, which give it outstanding thermal insula-tion properties. For that reason CR is highly rated by manufacturers of wetsuits for water sports – for divers, surfers and canoeists. Depending on the degree of thermal insulation required, the material used for the suits is between 2.5 and eight milli-meters thick. The thicker material is more insulat-ing but has less stretch and more buoyancy.Both sides of the rubber are normally coated with fabric, which has a closed surface and is less vul-nerable to damage. Single-sided coated material is mainly used for sealing strips inside the protec-

Protective clothing

Diving suit made out of the chloroprene rubber Baypren® from LANXESS.

Protective clothing for handling hazardous sub-stances usually contains elastomeric composite material.

SBR and XNBR rubber are often integrated into the soles of safety shoes and rubber boots.

Surfing fun in a (rub-ber) second skin made from Baypren®.

Without shock ab-sorbers, bridges like this twelve-kilome-ter-long structure in Portugal would not be able to withstand vibrations caused by traffic and wind for very long.

DAMPING

• Air suspension systems ensure a safe drive in trucks, even when carrying a 40-metric-ton load, and make for a comfortable ride in passenger vehicles.• Bearing/suspension systems with an integrated rubber spring and hydraulic damping on rail vehicle axles offer higher travel speeds, improved passenger comfort and a marked reduction in noise.• Bridges rest on elastomeric bearings whose func-tion is to transfer the forces generated by the inherent weight of the bridge and the traffic load as well as the braking forces and the wind load to the bridge piers and abutments. Bridge bearings have to accommo-date movement and torsion caused by traffic, tempera-ture variations, earthquakes, pre-stressing and also material changes such as shrinkage and creep.• Rubber bearings acting as shock absorbers protect houses in earthquake zones from collapsing as a result of seismic shocks and – last but not least –• Cars of all shapes and sizes traveling on country roads and motorways run on rubber tires to protect occupants and goods from vibration and reduce road noise (see page 76).These examples illustrate the variety of applica-tions and the diversity of the designs and operating mechanisms of dampers and suspension systems in which rubber is used. Products range from simple rubber components which almost completely isolate machines or individual assemblies from their environ-ment, rubber mats for gymnasts made from foamed Levapren® (EVM) and vast rubber insulating sheets on which entire building complexes are built, via air bel-lows, vibration dampers made from layers of metal and

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There is power in silence

DAMPING

An almost infinite variety of buffers and dampers comes into play wherever there is a need to lessen vibration and shock. Damping elements soften the effect of horizontal, vertical and torsional vibrations. Alongside traditional suspension struts and shock absorbers, rubber components are also widely used. In many cases manufacturers of dampers rely on natural rubber. But where damping properties are required in combination with heat resistance and resistance to fuel, oil, lubricants, ozone and hydraulic fluids, manu-facturers of bearings, suspension systems, vibration dampers and bellows often opt for the hydrogenated nitrile rubber Therban®. Without the use of dampers, motors and shafts, axles and truck fittings, bridge structures and buildings in earthquake zones would not only be shaken but in many cases would also fracture or collapse completely within a short space of time. For when vibrations gen-erated by pounding pistons, rotating drive shafts, un-even or winding roads, gusting winds or earthquakes build up, materials are easily damaged.For that reason • Vehicle engines are not mounted directly on the chassis but are bolted onto flexible rubber dampers or hydraulic bearings to prevent them from transferring their vibrations to the vehicle body.• Metal and rubber vibration dampers on drive shafts and crankshafts ensure smooth running of automo-biles.• Couplings fitted with damping elastomeric inserts protect the massive drive shafts in ships from damage due to vibration.

Damping effect

Torsional vibration damp-ers cushion vibrations in the crankshafts of modern diesel engines.

Established elastomer bearing systems are used in bridge design, for ex-ample. Such components can withstand vertical, horizontal and torsional vibrations.

and railway bridges for their damping action and for safety reasons. Bridge bearings are often made from chloroprene rubber such as Baypren® or from a blend based on natural rubber, into which one or more steel reinforcing layers are incorporated and which can also be strengthened by means of external steel reinforcing plates. These components can absorb vertical loads, horizontal movements and torsion around all axes.It is not only the commanders of military columns who know just how easily even foot traffic can cause a bridge to sway dangerously. The builders of the Millennium Bridge in London also came to this realization – albeit only after painful experience: The foot bridge in the east of London was opened in a blaze of publicity in June 2000, but when the first pedestrians crossed the suspended structure the architectural masterpiece began to sway so badly that it had to be closed just a day after the opening. Only after the installation of 91 horizontal and vertical shock absorbers, costing the equivalent of US$ 8.9 million, could the bridge be reopened some two years later. The vibration dampers are viscous dampers, in which rubber is used to prevent dirt, dust and moisture from penetrating the open reservoirs, which are filled with a viscous fluid or com-

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rubber, and hydraulic bearings, through to complex air suspension systems and couplings.

Damping protection for buildingsArchitects and structural engineers make use of the damping effect of rubber elements to protect buildings from collapsing under shock and vibration and to safe-guard people’s lives – and not only in potential earth-quake zones such as southern Europe, Asia and many parts of the Americas. Buildings in somewhat unusual locations have also been erected on rubber buffers to protect them from movement and noise from below. In around 1980, for example, a Berlin construction com-pany built a housing complex with 1,215 apartments on a plot on top of a motorway tunnel. To protect the building from vibration and the residents from intrusive noise, the two three-lane motorway tunnels under the apartment complex were routed over the parking garage located in the basement area of the complex and insulated from its roof with rubber anti-vibration bearings. In that way the loads on the tunnel were distributed over the vast foundation slab of the parking garage. Armored elastomeric bearings, pot bearings and shock absorbers are used in the construction of road

When the earth moves

In regions threatened by earthquakes modern build-ings are built on rubber to counter seismic shocks. At the same time, a heavy tuned mass damper under the roof ensures an oscilla-tion equilibrium.

Since the earthquake in Kobe many Japanese high-rise buildings have been protected against seismic shocks.

DAMPING

The closer the natural frequency of a high-rise build-ing to the vibration of the earthquake, the greater the danger that vibrations will build up in the building until ultimately it collapses. In order to contain this type of sympathetic vibration as far as possible, in addition to the vibration-absorbing rubber bearings in the foun-dations, modern buildings in earthquake zones also include tuned mass dampers under the roof – heavy weights which act as “balance weights” by swaying in the opposite direction to the house itself, thereby reducing the oscillation amplitude (see page 56).

Low-noise and low-vibration wind energyThe expansion of wind energy plays a key role in the plans of the European Union and the German gov-ernment to reduce carbon dioxide emissions by 20 percent and as much as 30 percent respectively by 2020. Yet existing and planned wind farms are not without their share of controversy. Onshore wind farms in particular often face opposition from local inhabit-ants on the grounds of noise pollution, and rotors sometimes break as a consequence of their natural vibration. The structure of the wind turbines has also been affected in some areas by powerful vibrations. Suppliers of wind turbines now use vibration dampers and bearing elements made from rubber or rubber-to-metal compounds at various points in the turbine to prevent vibration and noise generation. For instance, the gearboxes and generators, which weigh up to 60 metric tons and 20 metric tons respectively, are

pound. The damping action is achieved by means of a piston which extends into this compound from above and can generally move in a vertical and a horizontal direction. The damper is rather like a jar of honey into which a teaspoon is dipped.

Resistant to seismic shockThe catastrophic earthquake that hit the Japanese city of Kobe in 1995 provided a further incentive for scientists and engineers, who have been working for years to find a more reliable means of cushioning buildings against seismic shock. One of the options under consideration is to isolate the entire building from the subsoil by placing it on rubber bearings, which act as shock absorbers. This principle is used to protect safety-critical buildings, in particular from un-derground vibration: some nuclear power stations, for example, are built on a rubber layer. Research at the ELSA laboratory (European Laboratory for Structural Assessment) of the European Commission’s Joint Research Center, based in the Italian town of Ispra, has confirmed that this method is suitable for oil refiner-ies, chemical plants and hospitals as well as for civil defense and police infrastructures.

Absorbing vibrationsWhen designing buildings in seismically active areas, the natural frequency of the building – which depends on the building materials, the number of stories and the subsoil – must also be taken into consideration.

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Cushioning and damping

HyDrauliCs To prevenT “juDDer” According to the “Motorlexikon”, an online glossary of motor terminology, hydraulic damping of engine or gearbox bearings is used purely for improving suspension on uneven road surfaces. The resonance generated by the engine weight leads to an uncomfortable backlash, which passengers in the front of the car in particular perceive as poor suspension and attribute to the front axle. That is why reports of road tests often include the comment “Front axle judders”. Alongside lower costs, the main advantage of hydraulic dampers as compared to conventional vibration dampers lies in the fact that they can be precision-adjusted to isolate the resonant frequency that is causing the intrusive noise.At low oscillation amplitudes, the shear deformation of a rubber spring provides damping.At higher engine oscillation frequencies of around one to two centimeters on an uneven road surface, fluid in the hydraulic spring is displaced from one chamber to another. The rise in pressure causes the chamber to inflate and thus to act as a second spring – the “inflating spring”. As the fluid flows into the second chamber, the flow velocity causes turbulence to develop. This means that the damping effect is not

attributable to the viscosity of the fluid, so water with antifreeze is normally used as the hydraulic fluid.As part of a project funded by the German Federal Ministry for Education and Research, a new generation of hydraulic bearings has been developed in recent years: the MRF hydraulic bearing. This is an electrically control-lable engine bearing system for cars. The

unusual feature of this novel bearing is the use of a “magnetorheological fluid” (MRF) as the hydraulic fluid. This fluid contains small particles which can be magnetized. The application of controllable magnetic fields allows the properties of these bearings to be selectively adjusted. In particular, their rigidity, in other words their damping capacity, can be varied continuously across a wide frequency range. The fast reaction rate of the MRF means that MRF hydraulic bearings can adapt very quickly to changing operating conditions. Since car manufacturers also take the possible failure of the car’s auxiliary power supply into consideration in their calculations, permanent magnets ensure a “failsafe response” for MRF hydraulic bearings.This new multifunctional bearing is currently being trialed by BMW in a test vehicle.

Hydraulic bearings for engines, assem-blies and truck cabs absorb vibration and disturbing noise.

Air spring cushions made of inferior material can look like this after only a relatively short time. These burst air spring bel-lows for trailer axles did not pass the performance test.

With its optimized gear coupling, the Conti-Tech Vibration Control system ensures a good atmosphere in the new Mercedes-Benz C Class. The elastomer component serves to transfer power smoothly from the engine to the air-conditioning compressor.

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spring systems

unassuming poWerHousesAir bellows come into their own in applications involving strong lifting and pressing forces but offering limited installation space. For that reason they are central to industrial pneumatic applications. In particular, the woodworking and textile machine industries, materials handling and the food and construction industries all

use these powerful air bellows with their simple, low-wear and low-cost construction. Air bellows made from heat-resistant rubber grades such as Therban® from LANXESS are available for use in hot environments like the paper processing industry and the chemical industry.Like bias-ply tires, air

bellows are built from a fabric-reinforced rubber bellows. Unlike steel cylinders, air bellows require no mechanically moving parts such as pistons and piston rods. Air is supplied via a metal or plastic connection point. Air bellows – expansion bellows and rolling bellows – are generally expanded to a pressure of 8 bar and gener-ate forces of up to 440 kN.

supported on elastomeric bearings, which absorb the static and dynamic forces over a specified lifetime of 20 years and as far as possible isolate the structure-borne sound generated in the gearbox and generator from the frames. The correct use of gearbox bearings reduces vibration in the rotor blades and tower. Hous-ings such as the nacelle shell also have to be isolated from environmental vibration to prevent them from being damaged.

A safe and comfortable tripThe internal combustion engine in a vehicle provides the driving force – but the oscillating pistons and rotat-ing crankshaft along with the drive train connected to them are a constant source of vibration. If these movements were not damped and isolated to a large degree from the chassis and the body, a comfortable journey by car, bus or truck would be unthinkable. To isolate the vibration from the rest of the vehicle and its occupants, the engine and gearbox unit is fitted with powerful dampers known as unit bearings. They se-cure the engine block and gearbox to the vehicle body. These inconspicuous components perform a multi-tude of tasks. They have to prevent the low-frequency natural vibration of the engine – in neutral for example – from being transferred to the body in the form of noise and vibration. They also have to isolate the high-frequency vibrations that occur at full speed. What’s more, the bearings also have to absorb the shock arising from uneven road surfaces to ensure that the engine/gearbox unit does not make the vehicle start to judder (see also page 57). There is a conflict of objectives here, which the vehicle manufacturer has to try to resolve by means of a

trade-off – depending on the vehicle class – between comfort and driving dynamics, using rubber-to-metal bearings or hydraulic bearings, depending on prefer-ence and vehicle type. The choice is either to increase comfort by reducing noise, particularly in neutral, or to focus on driving dynamics by eliminating road-induced movement of major assemblies.In mid-range and high-end vehicles in particular, car manufacturers tend to opt for hydraulic-damping engine bearings, which form an adjustable connection between the drive and chassis, offering more effec-tive damping of strong vibrations – caused by load changes and juddering, for example – than rubber-to-metal bearings. Hydraulic bearings have been used in automotive construction since 1977. Since these bearings have to operate in a hot environ-ment, engine bearing manufacturers often use the high-performance rubber Therban®.Hydraulic bearings in modern commercial vehicles also deliver greater comfort in the driver’s cab by absorbing shock and vibration and at the same time by isolating the cab from engine noise and road noise.

Vibration dampersIntrusive and damaging vibrations also occur at shafts if their torsional vibration is not contained by means of damping elements. In adverse operating conditions the entire drive system can start to vibrate, leading to bothersome noise and mechanical damage. To offset this risk, car manufacturers fit the crankshaft with a torsional vibration damper. Torsional vibration dampers made from a metal-to-rubber compound are used for this purpose in the TDI engines in some Volkswagen models, for example. Therban® from LANXESS is an important component of the elastic insert. That is one reason why Volkswagen opted for vibra-tion absorbers from Paguag which, thanks to the use of the HNBR rubber Therban®, not only offer excellent damping properties but are also immune to aggressive fluids, withstand high dynamic forces and above all do not distort, even under extreme temperatures. Tem-peratures in the immediate vicinity of the engine can easily reach 150° C during operation – but Paguag torsional dampers with Therban® inserts can withstand continuous temperatures of 165° C and transient peaks of 180° C without being damaged.

On a bed of airAir springs in all types of vehicles are virtually synony-mous with comfort and adaptability. That is because the air-filled rubber bellows used in such suspension systems on axles or on each individual wheel not only absorb shock from the road surface and stop the vehicle from rolling on bends but also allow the vehicle to be adjusted to different heights and to different driver preferences: some higher-end saloons and sport utility vehicles (SUVs) allow drivers to choose between

Conical springs combine the function of steel coil springs and flexible axle bearings in a single com - ponent. They reduce noise and vibrations in rail vehicles.

ContiTech’s customized air spring system for the Citaro LE from Daimler subsidiary EvoBus saves valuable seconds when the vehicle is lowered at the bus stop.

DAMPING

Cost-effective bel-lows perform heavy-duty work.

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comfort or sport ride or between harder or softer sus-pension, depending on road conditions.Air suspension systems have been used in car building since the 1960s – in the legendary Borgward P 100, Mercedes 300 SL and Mercedes 600 Pullman (the “king” of limousines), for example, and in the hydro-pneumatic system used by Citroën. Their high cost meant that for a long time air suspen-sion systems were used in only a minority of cars, however. It is only since the late 1990s that they have broken through to a wider market. Car manufacturers now offer customers pneumatic suspension at least as an option on around three dozen vehicle models.In commercial vehicles and buses too, air suspension systems have become firmly established. In coaches and public service buses they are now classed as a standard fitting. The usual configuration is to have two air springs on the front axle and four on the rear axle. They not only provide a more comfortable ride but also maintain a constant step height, irrespective of the load. In modern buses – especially public transport buses – the air springs pneumatically lower one side of the vehicle (known as kneeling) to make it even easier for passengers to board and leave the bus – a great help for parents with pushchairs and for disabled passengers. The air-sprung axles of commercial vehicles also help to protect roads and goods, since their spring charac-teristics adjust to the vehicle load. In trucks air springs can be fitted to front, rear and trailing axles and to the

leading axle of articulated vehicles. Trailers and semi-trailers too are increasingly fitted with air springs to protect fragile goods and the vehicle body. There are normally two air springs behind each axle. In the case of multi-axle vehicles, one axle is often fitted with a lifting mechanism to conserve the tires when the vehicle is traveling without a load.

Well-cushioned train journeysThe chassis technology used for modern local, inter-city and high-speed trains and for goods trains has to meet high standards of comfort, safety and noise generation. Elastomeric spring elements are an essen-tial component of both the primary suspension system between the wheelsets and the bogie and the second-ary suspension system between the bogie and the railcar body. The primary suspension system guides the wheelsets, while the secondary suspension system offers flexible support for the railcar body. The system largely isolates it from track irregularities and allows the bogie to turn out on bends. The sec-ondary air springs are designed to have a lower natural frequency so as to minimize the transfer of vibration and provide constant level adjustment, in other words to keep the railcar at a constant height, regardless of whether it is fully occupied or not. This ensures that the step is always at the correct level in relation to the edge of the platform for boarding and alighting. In April 2006 the rubber special-ist ContiTech AG and the Swedish SKF group

vibration-free

rubber and hydraulics

The new Gigabox system comprising wheelset bear-ing and hydraulic spring with integrated rubber spring ensures hydraulic damping in rail vehicles, reduces screeching noise around bends and preserves the rails thanks to reduced vibration. The bearing spring concept in-creases service intervals to ten years or one million kilometers.

24 air springs lift the telescope and cushion it against vibrations from various directions.

A ContiTech air spring system ensures vibra-tion-free conditions on board the Strato-spheric Observatory for Infrared Astronomy (SOFIA). SOFIA is a Boeing 747 SP that has been transformed into a laboratory for investi-gating the formation of stars and planetary sys-tems from an altitude of 14 kilometers.

The ContiTech air spring system holds the 17 ton infrared telescope pre-cisely in its position.

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launched a new wheelset bearing and suspension system for rail vehicles, combining a rubber spring and hydraulic damping. In this system, known as the Giga-box, wear parts have been replaced by rubber guides, and the hydraulic damper adjusts automatically to the amplitude and is not subject to operational wear and tear. The manufacturer specifies service intervals of ten years or one million kilometers. Thanks to the improved ride qualities of the railcar, the Gigabox also reduces wear and tear on the entire train and rail system while at the same time significantly increasing running smoothness. The integrated rubber spring also takes over the wheel control function, thus improving safety at high speeds.

Operational reliability on the high seasSafety and reliability are also what count when it comes to the use of the high-performance rubber Therban® in ship couplings, sometimes of massive proportions. The task of the HNBR rubber in this application is to protect the ship’s diesel engine and drive shaft from damage and so to maintain opera-tional reliability over long distances. That is no mean feat. On cost grounds, the diesel engines of these ocean-going giants – tankers, container ships or float-

ing hotels, which can easily be as tall as a house – run on particularly heavy diesel fractions such as gas oil or heavy oil. However, since this fuel does not burn anywhere near as uniformly as the light diesel used by modern car engines, the irregular forces acting on the drive shaft, which transfers the engine torque – ranging from 2,400 Nm in yachts to 800,000 Nm in container ships – to the propeller, cause it to vibrate. If left unchecked, these vibrations can lead to damage or even failure of the drive.In order to absorb these vibrations, a coupling is installed between the diesel engine and drive shaft, the elastomeric insert in which absorbs the shock. Owing to its good dynamic properties, natural rub-ber is often preferred. The disadvantage, however, is that it ages prematurely in the hot environment laden with oil vapor and ozone. That is why the coupling manufacturer Vulkan Kupplungs- und Getriebebau GmbH & Co. KG, based in the German town of Herne in North-Rhine Westphalia, has also opted for the use of the hydrogenated HNBR rubber Therban®. Resistant to heat, oil, lubricants and ozone, this rubber plays an important part in extending the maintenance inter-val, thereby minimizing costly dock time. In order to deliver the performance profile demanded by Vulkan,

... In ocean-going giants ship couplings padded with the high-performance rubber Therban® cushion the oscillations and vibra-tions of the diesel engine.

A smooth journey thanks to the damping effect of Therban®.

DAMPING

a quiet run

Through its cushioning effect synthetic rubber is mild on the feet and limbs of sportsmen and -women …

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Active Body Control (ABC) is an electrohydraulic system based on a steel-spring suspension that automatically adapts the body setting according to the prevailing driving conditions. For this purpose, the spring struts are equipped with plungers (hydraulic cylinders) that are controlled by microprocessors and almost fully compensate the body’s lift, roll and pitch movements. Vibrations up to a frequency of five Hertz in the vehicle body can be absorbed by the system. Higher-frequency vibrations are absorbed by traditional steel springs and vibration dampers. The computer is fed information on the prevailing driving conditions from various sensors, and compares this with data from the pressure sensors in the spring struts and the height sensors on the axle guides. The ABC system uses this information to calculate the control signals that servohydraulic valves on the front and rear axles convert into precisely defined oil flows. When the oil flows into the plungers, these adjust the base points of the steel springs integrated into the spring struts, thereby generating the spring forces required to counteract the body movements. When cornering for example, the lateral acceleration sensor registers the centrifugal forces

and sends the requisite signal to the control unit. The control unit uses the speeds of the two front wheels to determine whether the car is entering a right-hand or left-hand curve, and signals to the plunger on the outside to extend, i.e. lift the vehicle. At the same time, the plunger on the inside receives the signal to release pressure, thereby lowering the vehicle on that side. During acceleration, the front axle is lowered and the rear axle raised – the opposite procedure applies to braking.In the hydraulic hoses used to distribute the hydraulic oil, the pressure is regulated to around 180 to 210 bar via the suction throttle valve.

iT’s all unDer ConTrol

rubber chemists at LANXESS adapted the properties of Therban® to the requirements of these particular couplings. The results of this collaborative project were unveiled at the “K 2007” plastics fair in Düsseldorf. The coupling presented there by LANXESS transfers the torque via eight cylindrical rubber elements, each weighing 350 g, positioned vertically to the direction of rotation in correspondingly shaped cavities between two metal coupling discs. Rather like press rollers, these cylinders have to resist substantial pressures and dynamic loads without developing any significant internal frictional heat.

Promising versatilityOnce again, this application of a high-performance rubber shows that modern elastomers are expected to offer an increasingly wide range of performance features. Damping action alone is no longer sufficient in many areas of application. Cost savings brought about by a long service life, higher requirements for heat resistance arising from strict noise protection regulations and the associated need to enclose units, ongoing customer demand for comfort and safety in transport and advances in engine and drive technol-ogy all mean that rubber damping elements also have to have an almost unlimited adaptability to ambient temperature, reliable resistance to a variety of aggres-

sive substances, a high load capacity under dynamic effects and properties that can be adjusted to specific applications.Only rubber products can be adapted with such flex-ibility and versatility to these diverse challenges.

potential medal-winner

a sensitive systemSensors, hydraulics, springs and dampers give vehicles fitted with an ABC system such as this current Mercedes C Class model a good stance.

1 Level sensors2 Valve block3 ABC suspension struts4 Oil tank5 Valve block with

pressure accumulator 6 Oil cooler7 Tandem pump8 Control devicem

Athletes cut a good figure on solid yet elastic rubber mats.

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Transporting earth from a mine by conveyor belt.

TRANSPORTING

The first thing that springs to mind when looking for a connection between rubber and transportation are the tires in the vehicles used to take people and goods from A to B. Indeed, tire production accounts for around 60 percent of rubber produced in the world – regardless of whether it’s natural or chemical-based (see also page 4 ff.). Nevertheless, despite these substantial quantities, tires are just one of many ways in which rubber is used to transport a wide range of goods and media. As an integral part of conveyor belts above and below ground, rubber belts are used to transport ore and coal, waste and excavated material, sand and stones, parcels and baggage and, last but not least, food bought at the supermarket (see page 66). People are also glad to make use of the moving walkways that transport them and their baggage along the long corridors in airports. They are made either of metal or – like the handrails – of rubber.

Hoses and cablesAir, gas, cement, extinguishing agents and liquids such as oil, gasoline, diesel, water, brake fluid and cooling agents also have their own special highways and byways. They flow under pressure or suction through hoses, cables and pipelines (see also page 70). Many of these pipes have to withstand aggressive liquids and gases or temperatures from minus 40 to over 200º C without becoming damaged. They must also hold out against physical strains such as friction on hard rock over long periods. Cables and hoses must be able to withstand a whole array of loads. Rubber chemists have synthetic rubbers and mixes to suit every environment, every task and every kind of product to be transported (see also page 42 ff.).

Rubber often has to compete with other materials such as steel and copper or plastics such as thermo-setting plastics or silicones. However, a rubber that has been designed to suit specific requirements is of-ten more efficient than its competitors, not to mention more environmentally friendly, because it generally contains neither plasticizers nor heavy metals.That’s why cables, insulating materials, floor coverings and conveyor belts based on rubber are the material of choice when safety – and particularly fire protec-tion – plays a key role. Halogen-free rubbers such as Levapren® (see also page 32) are not just able to withstand high temperatures, they are also flame-re-tardant, which means they are self-extinguishing and release virtually no noxious flue gases. Thanks to its low viscosity, this EVM rubber can also be mixed with a high proportion of halogen-free flame retardants without making it difficult to work with.For that reason, Levapren® is often used as the basis for hoses, insulating cable materials and floor cov-erings in airports, hospitals and other busy public buildings as well as in railway carriages, aircraft or in facilities for transporting crude oil and natural gas.

Safely conveying electricity With appropriate compounding, Levapren® is also ideal for electrical insulation, i.e. as a protective shield for the safe transportation of energy. The material‘s heat resistance has a major role to play here.However, when the focus is on “transportation”, let’s not forget about cylinders and rollers. Rollers coated with Therban® perform heavy-duty work day in, day out – regardless of whether they are used in the cargo hold of aircraft for conveying freight containers,

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On the move

TRANSPORTING

Versatile hoses

Whenever gasoline or oil flows through hoses, or ca-bles need to be positioned in a hot environment ...

…such as near engines, or when fire protection is of the essence, halogen-free rubber grades such as Levapren® are the answer.

surface exhibits excellent separation and carrying properties. The functional rubber surface designed specifically for letter transportation also protects sensi-tive surfaces and can withstand the extremely dynamic loads at the deflection rollers. LANXESS produces the rubber Krynac® X 740 for conveyor belt manufacturer Forbo Siegling GmbH specifically for this area of ap-plication. This rubber is produced using an emulsion process and is a terpolymer made from acrylonitrile, butadiene and an unsaturated carboxylic acid, which creates the hydrophilic properties of its surface.By way of contrast, the food industry requires con-veyor belts that are primarily resistant to hot water and grease; when transporting stones and bricks, the material must offer good tear resistance; and in indus-trial environments the material must be highly robust against oils and lubricants.

No slipping and slidingFloor covering plays a key role in transportation – be it on foot or on wheels. Architects and property devel-opers often opt for rubber floor coverings based on

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in paper production systems or in steel processing plants. Here they are not just subject to heavy loads – they also have to withstand high temperatures. This is particularly important when heavy loads are moved quickly on rollers and cylinders. The high contact pres-sure generated by high material speeds subjects the rubber coating to severe flexing. The heat that builds up during these processes would quickly age normal rubber and destroy it.

Endless cycleWith over 70 million letters being delivered to more than 40 million households every day, the letter centers of Deutsche Post have their work cut out to ensure fast and reliable transportation on their sort-ing lines. Each hour, between 30,000 and 60,000 envelopes pass through special scanners and on for further distribution – at a speed of around four meters per second. It’s rare for letters to be lost, and that’s because machine conveyors coated with the ex-tremely abrasion-resistant NBR rubber Krynac® X from LANXESS ensure reliable sorting – the hydrophilic

Floor coverings made of Krynac® give the neces-sary grip in sea rescue vessels when conditions at sea get rough.

TRANSPORTING

Strong floors

On floors subject to extreme stress such as in storage halls, hospitals and airports, rubber floor coverings ensure that objects and people can be transported safely.

for fire behavior, smoke generation and toxicity speci-fied by the International Maritime Organization (MIT) for seaworthy ships.

Brilliant print Alongside cylinders and rollers, blankets play a less conspicuous transportation role in offset printing presses. They transfer ink from the printing plate to the paper and are also responsible for transporting the paper with millimeter precision. The outer layer of these complex, multilayered high-tech products from ContiTech ElastomerCoating is made of the nitrile rubber Perbunan® from LANXESS. This chemical- and abrasion-resistant elastomer gives the blankets the absolutely homogeneous surface that is required for high dot and contour definition and excellent full-tone smoothness. In addition to the excellent chemical and oil resistance, which is key when it comes to cleaning the blankets, and its outstanding abrasion values, Per-bunan® can also be customized to meet the various requirements made of the surface characteristics of blankets in sheetfed and offset printing. Without rubber there’d be no razor-sharp glossy magazines.

Levapren® or blends of Levapren and nitrile rubber for a whole range of applications, including storage halls subject to extreme stress where forklifts are always on the move; hospitals and nursing homes, where beds and wheelchairs are constantly being moved around; and busy buildings such as airports, museums and train stations, such as the city terminal of the Transrapid in Shanghai. Depending on the area of application, these floor coverings – already exhibiting excellent load-bear-ing capacity and easy cleaning – can also be designed to dissipate electrostatic charges. They can also provide anti-slip properties and excellent floor sound-proofing, and are very comfortable to walk on thanks to their elas-ticity. What’s more, they can also be made from rubbers that are resistant to oil, alkalines, grease and acid, and can be filled with flame-retardant additives.Krynac® can withstand the toughest requirements in terms of fire protection, non-hazardous flue gases, anti-static properties and resistance against aggressive media such as oil, lubricants and salt water. That’s why the German Sea Rescue Service (DGzRS) chose floor coverings from the Freudenberg “norament®” range, which are all based on the NBR rubber Krynac® from LANXESS, for its latest and biggest sea rescue ves-sel “Hermann Marwede”. The “Hermann Marwede” showcases an array of rubber grades tailored to the precise application demands. Examples can be found on the bridge, in the deck’s anteroom, which is also home to the ship’s hospital, on the stairs and in the engine control room. They meet all the requirements

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Those were the days, when passengers walked from the terminal to the plane carrying their baggage, ready to put it down on the tarmac or on open trailers so that the ground staff could stow it safely in the plane’s hold. On landing, the same procedure applied, but in reverse. Then again, those were also the days when the captain could welcome and bid farewell to each and every passenger with a friendly handshake. Nowadays, with over four billion passengers a year worldwide, these customs exist only in the memory of older globetrotters or at airports in the back of beyond. Today, passengers drop their suitcases on a conveyor belt at the check-in counter, where it disappears into the airport’s seemingly endless catacombs. Major airports today are equipped with kilometer-long conveyor systems that transport items of baggage accommodated in containers. Barcodes are employed here for efficiency and to sort, transport, divert and store baggage quickly

and reliably. The belts reach speeds of up to 40 km/h. On arrival at the end of the computer-controlled trip, the items of baggage usually land on conveyor belts in the baggage reclaim area. These belts either consist of rubber-coated slat conveyors or inclined endless belts. Once here, the items of baggage lay on the rotating conveyor until they are claimed by their owners.As the conveyor belts have a tough workload – the con veyor system in terminal 2 at Munich Airport, for example, processes up to 14,000 pieces of baggage an hour at a speed of seven meters per second – the surfaces are usually made of rubber blends that are particularly resistant to wear and other physical loads.

Rubberized conveyor belts are a must in store-rooms and at airports.

State-Of-art cOnVeyOr SyStemS

reliability

The printing industry too relies on high-perfor-mance elastomers.

Baypren® is incorporated into the Fluidic Muscle MAS. Internal pressure leading to radial expan-sion causes a lengthwise contraction of the hose. This makes it possible to convey heavy loads safely and quickly.

DRIVE BELTS

The driving force Wherever something moves or is moved – be it under the hood of cars, in motorbikes, printing presses, mines, funfair rides or sawmills – you will be sure to find drive belts, V-belts or toothed belts of different cross-sections, lengths and materials for transmitting power and controlling other components. The tradi-tional flat leather belt has now largely been replaced

worn and brittle over time, with the result that they lost traction with the pulley and occasionally slipped through it.

The search for superior solutionsThe “balata belt” was the first solution to challenge the supremacy of the leather flat belt at the beginning of the 20th century. This belt was actually a cotton cloth soaked in latex from the sapodilla tree (also known as the balata or the marmalade plum tree). This belt material was much tougher and less flexible than other materials, which meant it did not have to be retightened as often. Next, belts made of rubber with woven fabric inlays and plastic (polyamide, poly-ester or aramid) made it big, as their surfaces offered more consistent adhesion to the drive pulley, thereby improving the power transmission. However, these solutions also failed to fully solve the problem of slip.

New shapes and profilesAs the materials changed, so did the cross-sections and surfaces of the belts. The rubber V-belt with its trapezoidal cross-section brought one major advan-tage: It adheres to two sides of the V-shaped pulley, resulting in higher power transmission. As V-belts are relatively stiff, they can be toothed to allow them to run without buckling when deflected by the smallest possible size of pulley. Thanks to their greater reliability and longer service life, belts gradually tapped into areas that had previ-ously been the sole domain of metal chains or cardan shafts. It was in vehicle construction in particular that belts of all kinds started to conquer new ground – driving generators, pumps and cooling systems or synchronizing camshafts and crankshafts. However,

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Able to cope with extreme loads: Toothed belts are on the verge of replacing chains in motorcycles as the usual form of secondary drive.

Durable conTrol belTs

by multifaceted high-tech products designed by skilled development departments from the rubber and chemical industry. However, in their day, leather belts were the inspiration for new solutions to problems that they themselves were unable to resolve. Due to their shape and material properties, leather belts were unable to maintain the tension required and became

Development stage

... that can drive several units simultaneously on both sides.

In cars, the charge cycle is controlled via valves and one or two camshafts. Each valve is assigned an eccentric cam on the camshaft, which pushes the valve open. When the cam rotates further, the valve is closed again by the valve spring. The camshaft is driven by the crankshaft via a toothed belt. The toothed belt is also responsible for synchronizing the rotation, as the camshaft turns exactly half as fast as the crankshaft, i.e. the transmission ratio is 2:1. This precise rotational synchronization demands an extremely reliable toothed belt, which is often made of Therban® from LANXESS as this elastomer material is able to withstand the high loads resulting from circulation velocities, flexing cycles, heat, cold, ozone, cooling agents and oil. Despite these high loads, toothed belts made of Therban®, together with an embedded glass cord whose teeth

are reinforced with a polyamide fabric, offer a minimum service life of 240,000 km.

The flat leather belt was the precursor to high-tech products made of high-performance rubber ...

camshafT vibraTion Damper 1 Toothed belt 2 Gear wheel 3 Torsional vibration damper4 Transmission disc5 Camshaft

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grooves that match these ribs. Thanks to this design, V-ribbed belts can run half a dozen units at the same time in serpentine drives. The latest V-ribbed belts can even survive without automatic adjusters through-out their service lives, which can be more than 200,000 kilometers, and in all operating conditions as they maintain the tension independently. This cuts down on weight and saves time and money.Thanks to their versatility, reliability and long service life, different kinds of belts are now opening up fields of application in vehicle construction and mechanical engineering that were previously reserved for drive elements made of metal, such as chains and shafts.

“Cut-throat competition”Motorbike manufacturers such as BMW, Harley David-son and Kawasaki are now fitting some of their models with heavy-duty toothed belts to drive the rear wheel instead of steel chains or cardan shafts. This cuts the weight and reduces maintenance because the drive belt does not need greasing or retightening over its ser-vice life of around 40,000 kilometers. Drivers of these types of motorbikes are also impressed by the drive’s direct response to changes in speed.The debate on fuel consumption and the related CO2

emissions is also spurring on manufacturers of drive belts and their suppliers in the chemical industry. For instance, Continental AG is marketing a toothed belt that also operates in oily environments as an alternative to chain drives. The oil-resistant toothed belt offers a number of benefits: It boasts around 30 percent lower friction losses than a chain drive, and cuts fuel con-sumption by 0.1 to 0.2 liters for every 100 kilometers, which also reduces CO2

emissions. The belt also runs more quietly and takes up less space. The toothed belts consist of three functional areas – an oil-resistant HNBR elastomer such as Therban® which is used as the basis of the belt, a glass cord, which trans-fers power from one gear to the next, and a polyamide material that reduces wear, ensures an optimal grip with the belt underbody, and cuts friction on the surface of the toothed pulley.

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the materials used to make the belts have to do more than just transfer power – they also have to withstand the toughest of conditions. High-tech belts in cars must withstand heat (up to 170° C), cold (down to minus 40° C), oil, ozone, extremely dynamic loads and wear. What’s more, heavy-duty belts have to drive several units at the same time and exhibit high fatigue strength under reverse bending stresses throughout an engine’s service life. Belts based on Therban® are ideal for these sorts of applications. The Conti HSN-Power®, developed by Continental AG in cooperation with LANXESS, is a good example.

Tasks of toothed beltsThe teeth of these heavy-duty belts are reinforced with aramid fibers. The tension member inside the belt is a glass cord, which ensures high bending fatigue strength, water resistance and linear stability.Toothed belts are ideal for applications that demand zero slip. Perfectly matched toothed belts and toothed pulleys ensure that this is the case. Toothed belts can also be used to bridge longer distances of up to three meters. Moreover, they exhibit extremely low levels of friction, are smooth-running and are much quieter than link chains, for example. The compact design of state-of-the-art car engines demands even more from these specialist belts. To be able to drive and synchronize as many units as pos-sible at the same time, i.e. to save space and reduce the weight, toothed belts have been developed with teeth both inside and outside. The teeth come in a whole range of sizes and different spacings, thus enabling various types of auxiliary systems – cool-ing water pumps, air-conditioning compressors and generators – to be driven with both sides of the belt, given the corresponding deflection.

Powerful V-ribbed beltsV-ribbed belts, a development of the V-belt, are also ideal for driving multiple auxiliary systems efficiently. The cross-section of this belt is fitted with wedge-shaped ribs that run lengthwise. The pulley has

All sorts of belts – be they toothed belts, V-belts, V-ribbed belts or double-toothed belts – are used in print-ing presses to enable fast and seamless operation. Drive belts have a direct impact on the quality of print products. Toothed belts must run without slip to ensure consistent print results – even when the machine is operated at different speeds due to technical factors in production – and V-belts are designed to ensure smooth running for top-quality results in sheetfed printing. Additionally, heavy-duty belts employed in reel splicers in rotary press-es must have a high load-bearing capacity.

smooth running

DRIVE BELTS

Product Nitrile-butadiene rubber,NBR

Ethylene-vinyl acetate rubber, EVM

Hydrogenated nitrile rub-ber, HNBR

Microgels

Patent DE 102007039527.4 DE 10200704 1055.9 DE 102005062075.2 EP-A-1401951

Subject Ruthenium and osmium car-bene complex catalysts with fluorenylidene ligands

EVM – embedding com-pound for solar modules

Process for the manufacture of rubber-plastic composites

Rubber compounds contain-ing carbon black, silica and rubber gel

Significance New type of metal complexes for targeted manufacture of particular NBR rubber grades as starting materials for HNBR high-performance rubber

New type of embedding compound for photovoltaic solar cells with benefits for manufacturing and durability

Reduction in expenditure of labor and proportion of defec-tive parts in the manufacture of high-performance rubber (HNBR) – thermoplastic com-posites in one operation

Further improvement, for example, in the relationship between wet grip (braking distance), abrasion and roll-ing resistance (fuel consump-tion) in tires

PATENTS SAfEguARD THE fuTuRE

oped procedures for controlling the properties of mate-rials should pave the way for further improvements.

Molecular fine-tuningNanotechnology plays a key role here. For example, it is already possible to modify the surfaces of filler particles with individual molecules to create a mate-rial with different characteristics. Nanotechnology gives an insight into structures over the range of several 100 nm. These microstructures can influence, for example, the amount of energy required to drive a conveyor belt. Modifications can also be made to improve a material’s resistance to extreme tempera-tures, different media or wear. The structures of additives and fillers for elastomers, which have a major impact on the properties of a material, can also be “fine-tuned” by nanotechnology to further optimize particular features of rubber. Last but not least, nanotechnology will help develop more proficient materials to make more efficient use of the world’s ever-diminishing and increasingly expensive crude oil resources.

Environmentally friendlyA function that automatically switches a car’s engine off and on in stop-and-go mode is also helping to reduce fuel consumption and, therefore, CO

2 emis-

sions. The engine is switched off, for example, when a car stops at a red light, and is restarted automatically when the driver steps on the clutch. This task is per-formed by an electric motor that is connected to the combustion engine via a special heavy-duty V-ribbed belt. This belt-driven starter/alternator should cut CO2

emissions in urban traffic by between five and ten percent. The elastic belt transmits torque reliably and quietly. What’s more, the belt’s low weight and com-pact size has a positive impact on the whole system.

Heavy-duty materialSpecial toothed belts are also in action in production facilities. For example, they drive coating and skid sys-tems for transporting machine and car parts. They not only impress with their high load-bearing capacity and wear resistance, they are also free from sub stances that allow paint adhesion. The tension member of these toothed belts, made of a heavy-duty material such as aramid cord, is embedded in an HNBR mix, making it resistant to ozone and oil. The potential of rubber and all its variants is far from exhausted in the field of drive engineering. Experts do not expect any quantum leaps in terms of develop-ment, but new technical challenges and highly devel-

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Toothed belts made of high- quality elastomers and base materials reliably transmit enormous forces.

Driving force

Toothed belts ...... are characterized by high smoothness and control precision.

v-belts ...... provide higher drive-train friction than flat belts thanks to their cross- section.

multi-speed belts ...... have a greater broadness than thickness and are suit-able for variable speeds.

Garden hoses without adverse effectsThe variety and versatility of hoses certainly seems to be inexhaustible. Rubber chemists can design hose properties to perfectly match the subsequent application requirements. Even a “simple” garden hose is quite complicated. It usually consists of three layers – the outer casing, reinforcement and core. The outer casing and core are usually made of PVC, while the reinforcement consists of a synthetic fabric. This is the most common design, but it is not necessarily the best. Ecological tests reveal a number of disadvantages associated with PVC hoses. They contain plasticizers to provide flexibility and to ensure that the PVC does not become tough and brittle in cold temperatures. They also include heavy metals and stabilizers. When hoses are used for irrigation, these additives – some of which are poisonous – can contaminate plants and enter the food chain, thus creating a potential risk to human health. They also release dioxins when they are burnt on disposal. Ecologically sound alternatives to PVC here are garden hoses made of rubber, preferably ethylenepropylenediene rubber (EPDM) such as Buna® EP or

Flexible and adaptableNo matter where they are used – be it in cars, machine tools, hydrostatic drives, aircraft, in the garden, on oil platforms, in the mining industry, in the fire department, at home or in concrete pumps – hoses perform their functions reliably and often under extremely tough conditions. These flexible lines transport water, hydraulic oil, gasoline, diesel, urea, gases and solid materials. Without hoses made of many different elastomers and plastics in various lengths, diameters and with the broadest possible range of properties, it would be impossible to make cars more environmentally friendly, to fully exploit oil deposits, to move robot arms, or even to water gardens. What’s more, these versatile hoses must be designed to withstand a whole range of conditions, including heat and aggressive liquids, cold and high pressure, mechanical loads and ozone, oxygen and high levels of friction. In other words, hose manufacturers and their suppliers are faced with a tough job. And yet there doesn’t seem to be a problem that can’t be solved with rubber, rubber chemicals and fillers in tandem with other materials such as plastics, fibers and metal wires.

Fire hose dimensions

A: Internal diameter 110 mmB: Internal diameter 75 mm, length 15 or 20 mC: Internal diameter 52 mm, length 15 mC: Internal diameter 42 mm, length 15 mD: Internal diameter 25 mm, length 5 or 10 mS: Internal diameter 28 or 35 mm, length 30 or 50 m; dimensionally stable

Whether water, gasoline, concrete or coarse-grained sludge, hoses transport all sorts of media.

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chloroprene rubber such as Baypren®. These materials do not harden in cold temperatures. They are also torsionally rigid, buckleproof and abrasionresistant. Over and above this, they are immune to oxygen and ozone and boast a long service life (see right). Hoses with an outer casing made of the chloroprene rubber (CR) Baypren® number among the multipurpose industrial hoses that function equally well in hydraulic systems as in earthmoving machinery, as they can withstand extremely high loads and are resistant to oil, ozone, cold and heat. Heavyduty hoses are usually equipped with a fourth component for protection against high pressures and partial vacuum. In this case, a coil is inserted below the outer casing and reinforcement to stop the hoses buckling and to ensure that they do not contract when subject to partial vacuum.

All-rounder under the hood The variety of hoses and cables used in a car is increasing as automobile construction technology steadily develops. A whole range of components – including pipes for fuel systems, cooling circuits, oil circulation, heating systems and power steering, brakes (see the box below), hydraulic chassis systems (for example ABC = Active Body Control), turbo charging systems, the automatic cleaning of particulate filters in diesel vehicles and hoses for innovative SCR exhaust gas treatment for diesel engines (see also page 72) – demand high-tech hoses tailored specifically to their area of application and the medium to be transported.The more hoses that are installed in a car, the more automobile manufacturers are concerned to keep

A high-quality garden hose exhibits the follow-ing features:• It is torsionally rigid and buckleproof, and can be easily wound by hand or rolled on and off a hose reel.• It has high tensile strength, and is compres-sion-proof and wearresistant. It can also en-dure the high mechanical loads that occur during rolling and pulling, and can withstand pressure of up to 15 bar without bursting. It is weather-resistant against UV rays, frost and warmth from sunlight.• It is durable and remains flexible, maintaining its bending radius for many years.• If possible, it should contain no noxious sub-stances (such as heavy metals), as these can enter the irrigation water, contaminating the ground and thereby posing a risk to health on entering the food chain. These requirements can only be met by a high-quality garden hose, which in turn must be made of a weather-proof rubber with a high load-bearing capacity, such as Buna® EP or Baypren®.

In the summer, there’s almost no getting away from warnings of “ground-level ozone”. Summer smog is caused primarily by nitrogen oxides (NOx) generated through the combustion of diesel fuels in trucks and cars. This happens because ozone is created from the chemical reaction between volatile organic hydrocarbons – such as gasoline fumes – and nitrogen oxides, air and sunlight.To eliminate nitrogen oxides from exhaust gases, it is best to neutralize them as soon as they are produced. This is done through a process of exhaust gas treatment known as Selective Catalytic Reduction (SCR). Liquid urea (AdBlue) from an additional tank is injected via a hose line into the hot exhaust gas flow upstream of a catalytic converter. This process releases ammonia, which reacts with the nitrogen oxides to form nitrogen and water, which are harmless. In other words, the urea acts as a “store” for the ammonia. Although urea solutions are safe for humans, they are too alkaline for normal

rubber, which is why the AdBlue system designers prefer to use the ethylene-propylene copolymer (EPDM) Buna® EP for the urea hose line. Urea and ammonia have only a negligible impact on this rubber. What’s more, it is flexible without the addition of plasticizers and can withstand the high temperatures close to the engine and catalytic converter.

To ensure operational reliability even in cold winter temperatures (the urea solution freezes at minus 11º C), the hose is heated electrically. In this way, manufacturers such as ContiTech ensure that the system is fully operational within 15 minutes of the engine being started. Thanks to this heatable hose line, the system can be used at temperatures as low as minus 40º C.

Clean diesel engines thanks to Buna® eP

Quality characteristics

the weight and costs in check. That is why they are increasingly opting for oil cooler hoses made of the HNBR rubber Therban®. Unlike NBR rubber, Therban® is resistant to ozone, which means that it does not require a special protective layer against the aggressive gas that causes other types of rubber to tear and age prematurely. This type of oil cooler hose needs just one material, making it thinner, lighter and more costeffective.The increasingly strict exhaust regulations in Europe, the United States and Japan will soon make the use of particulate filters in vehicles with diesel engines unavoidable. Even now, the EURO 4 standard sets a maximum value of only 0.025 g/km for particulate emissions. The automotive industry expects that the coming EURO 5 standard will make the use of diesel particulate filters virtually mandatory.State-of-the-art particulate filters no longer have to be replaced regularly – they are cleaned automatically during operation. For this purpose, air is supplied via a side channel blower and a temperatureresistant hose to a diesel burner. Here, all the residues in the filter are burnt off against the engine exhaust gas flow, converting all the soot particles and deposited hydrocarbon compounds into CO, CO2 and steam. The hoses used to supply oxygen are often made of Therban® (to withstand continuous temperatures of 160º C).Environmental awareness has also shaped the development of vehicle airconditioning systems using the natural cooling agent CO2. Although legislation making environmentally friendly cooling agents (such as CO2) mandatory is not scheduled until 2011, manufacturers of airconditioning systems and their suppliers are already preparing to meet the future require

Heatable hose for liquid urea for treating exhaust gas by the SCR process.

HOSES

hose. An outer casing 2.5 millimeters thick is usually sprayed on to protect the hose from external damage. The rubber used is an extremely wearresistant and weatherproof mix based on natural rubber. To meet the wideranging needs of customers, concrete conveying hoses are produced using different recipes depending on the particular area of application. However, the end hose, that is, the part at which the operator works, poses significant risks. Uncontrolled pressure changes in the pump line triggered by jams or air pockets can cause conventional end hoses to make sudden jolting movements, injuring those close by. According to the employers’ accident liability insurance associations, these sorts of incidents account for 80 percent of all accidents involving concrete pumps. The prize-winning “Steady Hose” from the concrete pump manufacturer Putzmeister is the solution. The trick to this “damped” end hose is essentially the new design of the reinforcement fabric and softer hose material, which prevent the hose from making sudden jolting movements, thus making it much easier to handle. SBR rubber, such as Krylene® or Krynol®, is ideal for these types of applications.

Hoses for the fire departmentAn overview of the variety of hoses available on the market today wouldn’t be complete without taking a look at fire hoses. There are basically two kinds of fire hose – pressure hoses and suction hoses.Pressure hoses, through which the extinguishing agent is pumped at a pressure of between five and ten bar, are usually made of reinforced fibers (polyester) and sealed inside with a rubber coating. When they are not under pressure, the hoses are flat, enabling them to be rolled up or folded together for compact transportation. Fire hoses are available in different lengths and diameters depending on where they are used. In contrast to pressure hoses, suction hoses are di

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ments. For example, the rubber specialist ContiTech in Hanover, Germany, is developing a CO2 airconditioning hose, which – in contrast to all known stainless steel corrugated components – allows very tight bending radii as the barrier layer, while ensuring a low level of permeation. In this way, the hose wall ensures that only a negligible amount of CO2 can escape. A pol ymer barrier layer effectively retains the CO2, while an elastomer inner layer, like the barrier layer, is also resistant to the cold machine oil in the airconditioning system. A highstrength pressurebearing material made of aramid fiber ensures resistance to pressures of more than 600 bar. An outer layer made of an EPM elastomer protects against all the loads that usually occur in the engine compartment. At present, the CO2 hose cannot yet withstand temperatures of up to 100º C. However, by the time the component is ready for series production in 2011, suitable materials able to withstand temperatures of up to 180º C should have been developed for the hot gas path.

Safer concrete pump hosesWhile most hoses in an automobile are hidden under the hood or in the braking system, it’s quite a different story with concrete pumps. The hoses here are a very visible – and sometimes rather headstrong – part of the system. The highpressure conveyor hoses of concrete pumps, which can reach up to 40 meters in length with internal diameters of up to 200 millimeters, have to withstand operating pressures of 85 bar and extremely tough operating conditions. That’s why these flexible conveying hoses are made up of several layers: The core, which comprises a strong rubber material some six to seven millimeters thick, is surrounded by a fine lattice of steel wire. The strength of the mesh and the individual steel wires is based on the permitted operating pressure. In extreme cases, up to six wire layers are incorporated into the

saFety FaCtorBrake fluids usually comprise polyglycol compounds and are able to absorb water from the air. The water obtained from the air humidity is completely dissolved in the brake fluid (the brake fluid is hygroscopic), which means that no drops are formed. Drops of water would cause corrosion in the brake lines and freeze at low tempera-tures, posing a big safety risk. However, the water absorption lowers the boiling point of the brake fluid, which is counterproductive in a braking system. A high boiling point is essential to ensure the reliability of brakes as, during longer

braking periods, frictional heat from the brake discs (which can rise to 800º C) is also transferred to the brake fluid. If the water causes the brake fluid to boil and generate air bubbles, the braking action deteriorates significantly, leaving the driver with no braking power. The more water there is in the brake fluid, the earlier the fuel vapor lock sets in (wet boiling point). Consequently, the proportion of water in the brake fluid must not exceed three percent. That’s why a regular checkup and replacement of the brake fluid every one or two years is part of the

mandatory vehicle inspection service.To keep the water absorption as low as possible, hose manufacturers often use an EPDM rubber such as Buna® EP. This rubber is immune to

the aggressive brake fluid and allows next to no permeation, which protects the braking system against the ingress of water. Brake fluids and their boiling temperatures are classified

according to DOT (Depart-ment of Transportation): DOT 3 = 205º C, DOT 4 = 230 - 300º C and DOT 5 = 260º C.

safe concrete pump

High-tech in the end-hose of concrete pumps: With the “Steady Hose” system, softer hose material made of SBR rubber and a new type of reinforcement fabric prevent uncontrolled jolting movements.

HOSES

Immune to aggressive brake fluid: hoses made of EPDM rubber.

of fire. These special rubber mixes are flame-retardant, which means they are basically selfextinguishing in the event of fire. They are also halogen-free so that they don’t generate noxious gases on combustion. Hoses and foam insulating materials made of Leva pren® meet all these criteria, thereby making an important contribution to environmental protection (energy conservation) and to safety in busy buildings.Therefore, hoses are not just hollow bodies for transporting liquids, bulk goods or cooling and heating energy, they also perform a whole range of additional tasks wherever they are deployed. In fact, it is hoses that make many stateoftheart technologies possible in the first place.

mensionally stable so that they do not contract when subject to low pressure during the suction process. They are used when water is taken from an open body of water by means of a centrifugal fire fighting pump. Several suction hoses are used to create a suction line.

Insulating propertiesThermal insulating hoses make a key contribution to climate protection. They prevent the loss of heat and cold in cables and pipes in airconditioning and heating systems or during the transportation of molten material in industrial applications. The media transported in the pipes can only be kept at the required temperature when the lines themselves act as an insulator or when the sheathing around metal pipes protects against warming or cooling. Thermal insulating hoses made of the EPDM rubber Buna® EP have proven to be a costeffective alternative to multilayer plastic or metal pipes in this area of application due to their temperature and ozone resistance. As such lines usually run through buildings in which people live, work, relax or travel through, the systems for airconditioning, central heating and electricity supply have to do more than provide reliable insulation. They must also be designed so they do not combust or release poisonous flue gases in the event

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Flame-retardant materials for cables and hoses reduce the fire risk in heavily frequented buildings.

Built-in fire protectionThe demand for flame retar-dant materials is on the rise in the construction and auto-motive industries, as well as in the electrical/electronics product segment. LANXESS is there to meet it not only with elastomers like Levapren® and Therban®, offering adjustable flame retardance without the use of halogen compounds, but also with a proven range of phosphorus-based flame retardants. Products from the Disflamoll® and Levagard® lines reduce the flammability of plastics and improve their processing characteristics or elasticity. Bayfomox® is a raw material system for the manufac-ture of molded parts with extended fire endurance for use in structural fire protec-tion. Flame retardants must inhibit, delay or suppress combustion processes. They take effect in one or more phases of combustion: heat-ing, decomposition, ignition, flame spread and smoke formation. Their mode of action during the burning process may be chemical or physical, with several reac-tions possibly taking place simultaneously.

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Grips used in sports equipment often comprise blends with a “rubber feeling”.

Synthetic rubbers have long been used as elastomers in many areas of industrial production. They are em-ployed in a wide range of fields, including the automo-tive, electrical/electronics and building industries, and are used in packaging, protective films, adhesives, toys, clothing and sports goods. And yet, there is still a seemingly endless array of potential applications for the versatile products of synthetic rubber manufacturers. The key is to unlock the potential of new technologies. That’s why LANXESS, one of the world’s leading suppliers of technical rubbers, invests more than EUR 100 million each year in research and develop-ment. The Leverkusen-based company allocates its research investment budget according to the requirements of the markets and individual custom-ers that rubber chemists at LANXESS are working with on specific applications. Besides optimizing its process engineering operations, LANXESS is mainly concerned with improving its existing products and applications. At present, around three-quarters of the company’s R&D projects fall within this category.

Innovations for cable manufacturersThe company’s development work and focal points are often prescribed by the tough requirements facing rubbers, including extreme temperatures,

aggressive media and tough mechanical loads – and all this must be accomplished using extremely cost-ef-fective processes.A wide spectrum of promising areas of application can be opened up by combining rubber with metals, creating blends of plastics and elastomers and tap-ping into the broad field of adhesives.

High-performance cables for submarinesHowever, new types of compounds and mixtures of tried-and-tested high-performance rubbers also open up new areas of application under extreme ambient conditions. For example, cable experts at LANXESS worked hand-in-hand with the cable manufacturer Leoni to develop special cables for submarines (see picture above). This innovative material, comprising a blend of the high-performance rubbers Levapren® and Therban® and other materials, combines seven key properties. It is halogen-free, flame-retardant, oil-resistant, resistant to sea water and extremely flexible. It also exhibits very low smoke density and low toxicity in the event of fire, which is vital for the functionality of submarines.A further new area of application for rubber prod-ucts is provided by the timber-processing industry. Mixtures of sawdust, PP and EPDM rubber can be

Made-to-measure innovations

Camera grips are sweatresistant and pleasant to the touch.

Skin friendly

Special cable insulation based on Levapren® and Therban® improves the safety of submarines.

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extruded into wood-like panels, which can be pro-cessed, for example, into highly stable, impact-resis-tant door skins.EPDM rubber also has a great to deal offer in other areas of application, e.g. it is used as an additive in engine oils and helps keep the viscosity of multigrade oils constant in a broad temperature range, thereby minimizing wear of metal parts in engines. Polymers added to the oil used in power saws also ensure that the chain is adequately lubricated.

CompoundsThermoplastic elastomers (TPE), i.e. compounds made of polypropylene, polyethylene or polyvinyl chloride (PVC) and elastomers, also offer a seemingly endless array of potential applications. TPE com-pounds are not only ideal for all processing methods for conventional plastics, they also offer virtually unlim-ited scope for design and functionality. These plastic-elastomer materials can be used in countless products thanks to their outstanding properties. They can be soft or hard, brightly colored and resistant to aggres-sive media. They also adhere well to thermoplastics and are pleasant to the touch. Their attractive, rubber-like surface makes blends of plastic and EPDM rubber (such as Buna® EP) the material of choice for the grips of sports equipment, toys and the rubber parts of cell phones and cameras. What’s more, these materials do not age prematurely when exposed to sweat.The list of applications for plastic-elastomer blends is virtually limitless – from teething rings for babies to toothbrushes.

Versatile adhesive raw materialElastomers also enter into close bonds with met-als thanks to the “irresistible” adhesive power of EVM rubbers such as Levamelt® from LANXESS. As a result of its chemical flexibility, this adhesive raw material can be adapted to suit a wide range of substrates and requirements – from “bombproof”, permanent adhesion instead of welding or screw-ing to easily detachable films for adhesion to glass or for use on car bodies as protection against stone chippings. LANXESS offers these types of products in the form of ethylene-vinyl acetate copolymers, and is driving forward the development of made-to-measure adhesive solutions based on Levamelt®. The flexible polarity of the rubber means that these adhesive raw materials can be adapted to the individual require-ments of the substrate being bonded – from bomb-proof bonding of bodywork parts to easily detachable sticky notes.Levamelt® adhesives can also be optimally matched to the surface characteristics of fresh paintwork and are therefore ideal for the protective films on new cars to ensure that they make it safely from the manufac-turer to the dealer. Major automobile manufacturers

rely on easily detachable films incorporating an adhe-sive layer made of raw materials from the Levamelt® range to protect the paintwork and glass of new cars from dust, dirt and loose chippings during transporta-tion from the factory.

Nano-sized modifierThe high-tech product Nanoprene is one of LANXESS’s latest developments. This emulsion styrene-butadiene rubber (ESBR) is a gel with nano-sized particles, a precisely defined molecular struc-ture and a chemically controllable surface functional-ity. Nanoprene is a versatile additive that opens up new technological possibilities for the plastics and rubber industries. For example, tires with Nanoprene nanoparticles added to their tread mix adhere far bet-ter to dry and wet roads and demonstrate improved abrasion resistance without showing any detrimental impact on rolling resistance. Nanotechnology thus transforms ordinary ESBR rub-ber into a high-quality specialty product.The in-depth research and development activities of LANXESS will soon generate many more new prod-ucts and tap into additional areas of application.

OPPORTUNITIES

In need of protection

Rubber and plastic combine to create blends for keyboards and grips that are sweatresistant and pleasant to the touch.

Levamelt® adhesives protect new cars against stone chippings and scratches on the way from the manufacturer to the dealer.

“Green tires” help to save fuel thanks to special rubber components.

Really, it all came about because Scotsman John Boyd Dunlop grew fed up of listening to complaints from his ten-year-old son about his bike. The boy had been given a tricycle as a present but was not very happy with it, since riding around the bumpy street on its wooden wheels proved to be a painful experience for his posterior. So his father, a wealthy veterinary surgeon and passionate amateur inventor, set about finding a remedy for the problem to relieve his son’s frustration. That, basically, is how he came to invent the air-filled bicycle tire. Without this epochal event in 1888, motorized mobility on two, three, four and more wheels would hardly have developed into the global mass movement it is today. What was it exactly that Dunlop invented to keep his family happy? Legend has it that he made a tube out of his rubber apron, converted a baby’s dummy into a valve, wrapped his creation in canvass bandaging and then mounted it on to the rims of the tricycle wheels. To pump in the air he apparently used a football pump. When Dunlop saw how happy his son was cycling on the cobbled streets, he decided to become a tire manufacturer. And although he soon sold off the firm that he founded in London in 1898, the company kept its name and has done ever since.

A long and close relationshipTo begin with, it was bicycles – already fairly widespread – that profited from the comfort and convenience of Dunlop’s tires. But it was not long before the first auto pioneers started to show an interest in this more comfortable way of traveling over the rough tracks of that time. The first cars to run on air-filled tires began appearing on Europe’s roads around 1890. That was just the beginning of what was to prove to be a long and close relationship between the vehicle and the tire. Engineers and chemists made rapid progress in developing materials to take the tire from its earliest beginnings to today’s high-tech products – tires that allow modern cars to travel at speeds of more than 300 kilometers per hour, ensure a secure, firm grip on the road come rain, snow or ice, can bear loads weigh-ing hundreds of tons, withstand the hard landing of a Jumbo jet, enable mountainbikers to ride up and down rocky terrain and carry vehicles safely onwards even when they run out of air.

For more than a century, tire manufacturers and auto-mobile makers have continually spurred each other on to achieve further advances.As early as 1890, a patent was granted for the first tire with steel wire beading. This secured it more firmly to the rim and made fitting and dismantling much easier – an important criterion since in those days car tires were still very susceptible to punctures and laboriously difficult for drivers to repair.

Pioneers of the tireAn important contribution to the strengthening of tires was made at the end of the 19th and beginning of the 20th cen-turies by the brothers André and Edouard Michelin. After experiencing 50 breakdowns and 22 highly complicated

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The legs of the car

John Boyd Dunlop (above left) took a

“hands on” approach to testing his tires before fitting them to his son’s cycle. As early as 1898, Continental started series production of pneumatic tires for cars (above right). Tire machines for mass production established themselves from the mid-1920s onwards.

FirsT aTTempTs

THE HISTORY OF TIRES

tire changes in the Paris-Bordeaux-Paris car race of 1895, they concentrated their efforts on improving reliability.

Pioneers of the tireWith increasing success. In 1899, the Belgian Camille Jenatzky became the first person to exceed the magic speed barrier of 100 kilometers per hour, steering an electromobile equipped with special Michelin tires. In the same year Continental was the first company in Germany to add tires to its product range. For the price of 269 marks, Continental promised customers pneu-matic tires with an average life span of 500 kilometers! In 1904 for the first time, car tires were given a cross-rib tread pattern to ensure better grip on the road surface. Experiments in the same year also showed that the strength of the rubber could be significantly improved and the life of the tire extended by adding carbon black to the compound. However, this com-pound did not firmly establish itself worldwide until after 1918.1918 also saw the debut of tires incorporating layers of twisted filaments of fabric cord – arranged parallel under the tread – that helped to increase stability by lowering the build-up of heat. From 1924 onwards,

Michelin replaced the hitherto hook-like bead with a mesh of wire inside the tire, enabling the tire to rest more securely on the rim. This construction became a regular feature thereafter and is still the standard today. Shortly before this innovation, in 1923, Michelin had signaled a new era in tire construction with its low-pres-sure balloon tire “Comfort”. This was a tire that could run on air pressure of just 2.5 bar and keep going for at least 15,000 kilometers.

MilestonesThe introduction of the cross-ply tire in 1930 marked a significant step forward in terms of comfort as well as safety in the event of tire failure. In this particular diagonal construction, the cord filaments were crossed over each other diagonally at an angle of 45 degrees, a method that revolutionized the stability of the tire. In 1933, the cotton filaments in the casing of the tire were replaced by more stable artificial fibers (such as rayon or nylon). And with the industrial production of Buna® in 1939, synthetic rubber became a vital com-ponent in the making of rubber compounds – and, as a result, of vehicle tires. The first tires to be made completely from synthetic

CROSS-PLY TIRES Up to the end of the 1960s, tires were usually cross-ply. This a construction whereby the carcass is lined with layers of cord – originally made of textile fibers, later rayon or nylon – crossing over each other at an angle to the direction of rota-tion. Seen from above, the layers form an X shape. The wider the angle, the greater the driving comfort. The narrower the angle, the greater the stability – at the cost of comfort.

RADIAL TIRESIn the 1970s radial tires, also known as belted tires, increasingly gained ground. In radials, the layers of cord in the carcass run from bead to bead at right angles to the direction of rotation. Radial tires are lighter, enhance performance, and offer superior traction, comfort and less rolling resistance. However, they require a steel cord belt.

RUN FLAT TIRESTo save space and material, many carmakers prefer to do without a spare tire. For this reason, tire manufactur-ers have developed tires that will keep on rolling without air in an emergency. As a rule, the driver can continue to

the next garage at a speed of 80 km/h thanks to self-supporting, reinforced

sidewalls that do not “cave in” on the complete loss of air pressure.

sTages oF developmenT

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Among the pioneers of the tire industry were the Michelin brothers André (left) and Edouard.


• In 1982 Michelin introduced the first specialized winter tires with sipes – fine cuts running across the tire tread to increase traction forces and provide con-siderably more grip on snow. Silica technology set the stage for a further leap in tire development. This filler helps, when used instead of carbon black, to reduce rolling resistance and thereby lowers fuel consumption – a development that has gathered enormous pace over the past few years as a result of the discussion on the lowering of CO2

emissions. Tire makers see the greatest potential for protecting the environment and minimizing fuel consumption in optimizing tire compounds and modifying the con-struction of the tire. Research departments have set themselves the challenging target of reducing rolling resistance by as much as 50 percent over the coming 25 to 30 years.This challenge needs to be seen against the back-ground of the ambitious targets already reached. Over the past 15 years, the leading tire makers have succeeded in lowering rolling resistance by some 30 percent. A vital role in further development will be played by even more intelligent applications of silica as fillers, sophisticated rubber compounds, tread pattern

rubber were launched by Continental in 1942. A year later, Continental was granted the patent for tubeless tires – something now taken for granted.

First steel-belted tiresIn 1946, Michelin marked a further milestone in the development of the tire with the introduction of the world’s first steel-belted tire. By arranging the metal thread mesh radially (i.e. at right angles to the centerline of the tire), the French manufacturer was able to replace the fabric cord tire. After the Second World War, the pace of innovation in the tire industry speeded up – not least thanks to the huge leap in mass motorization. • In 1950, the first mud and snow tires (M+S) ap-peared on the roads. • From 1960, Dunlop began systematically investigat-ing the hitherto neglected subject of aquaplaning. This unleashed a major contest in the industry to pro-duce intelligent tread patterns and innovative rubber compounds that would improve grip on wet surfaces.• In 1968 Pirelli supplied BMW with what was the first low-section tire. It meant the height of the sidewall of the tire was now only 70 percent of the tread width, considerably lessening “side rolling” at high speeds and improving steering stability. • In 1975 Michelin launched the first radial tire, com-bining two hitherto contradictory requirements: greater driving comfort and increased steering accuracy.

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Automobile tires are subject to fashion trends. Some, like the blue-colored ones, turned out to be flops. Illuminated tires (left), such as those offered by Goodyear in the 1960s, were not exactly a hit either. White sidewalls, on the other hand, were all the rage in the 1940s and 1950s. Wide-base tires (above left), originally a “must” for tuners, have found widespread popularity.

Tire FasHions

Michelin set new standards in the industry with the launch of its steel belt tire in 1946.

design, the composition of tire belts and the carcass. The positive features of the tire such as low rolling resistance, stability, good traction, high mileage perfor-mance and secure rim fit are largely hidden away on the inside.

Complex interiorIn a modern steel belt tire – nowadays state-of-the-art – there are likely to be anything up to 20 different rubber compounds and some 25 components such as rayon, nylon, wire mesh and steel wire. It is the tire’s tread that establishes contact with the road surface (see illustra-tion). Supported by its carcass, it provides traction and a firm grip when cornering. As a rule, the treads of summer tires have a higher proportion of synthetic rub-ber than winter tires. They are therefore harder, build up less heat and wear out more slowly.The carcass forms the supporting structure of the tire. It consists of multiple layers of fabric (known as cord lay-ers) that are independently sandwiched into the rubber. For this, tire manufacturers use materials such as steel cord and synthetic fibers. Stretched over them is a multi-

layered belt of twisted steel wire coated with brass and rubber. The belt is wrapped in a bandage of synthetic material such as nylon cord. This considerably improves running performance by reducing rolling resistance, enhancing cornering stability and lowering the build-up of heat. While the belt holds the undertread together, the inliner seals the carcass to the wheel rim. It is a layer of airtight rubber – generally a butyl compound – lami-nated to the inside of the tire to ensure air retention. In modern tires this thin inner layer replaces the function of the inner tube.The carcass is protected by sidewalls. The outer side of the tire is a particularly sensitive part and can easily be damaged if it hits the kerb during a parking maneuver. To protect against squeezing or tears, today’s tires are especially well-reinforced around the outer edge.The side and tread of the tire meet at the shoulder, while the sidewall and cord layers of the carcass join up in the bead. This ensures that the tire fits the rim. What the man in the street sees when he looks at a tire are the height, width and tread pattern. These “looks” tell us a lot about the performance of the tire.

The right gripThe intricate arrangement of bars, grooves, and sipes on the tread of the tire make up a particular pattern that

is designed to fulfill a number of different purposes. They are there to:

• ensure maximum power transmission and short braking distance by provid-

ing a firm grip of the road surface; • guarantee a firm grip on wet

surfaces, too;• prevent aquaplaning;• keep noise levels down to a minimum;• guarantee high mileage, and also • look sporty and dynamic.And then, of course, there are seasonal weather conditions that


1. The tread: Tread pattern and rubber compound influence grip.

2. The lining of cushion rubber under the tread joins the tread to the steel belt and carcass.

3. The upper steel belt and…

4. … lower steel belt influence the driving characteristics and shape of the tire.

5. The carcass, made of synthetic fiber, gives the tire support and shape.

6. The airtight inner liner replaces the tube.

7. Steel wires in the bead keep the tire safely attached to the wheel rim.

8. The sidewall bears the type designation and protects the car-cass from damage.

Tire ConsTrUCTion

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4

5

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6

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demand extra creativity from the tread pattern specialists. The basic elements of the tire’s tread pattern are the bars (or blocks), grooves and sipes. Sipes are fine slits in the tread that allow the bars to stretch on contact with the road and “grip” the surface. While the tread bars ensure grip with the ground surface, the grooves are designed to deal with wet conditions by channeling water away to the sides. This reduces the danger of aquaplaning. Summer tires, which frequently consist of two different rubber compounds – the softer cap on the upper part to secure road grip and the harder base to ensure more accurate steering – have a relatively high percentage of bars in the tread pattern design. In the case of narrow tires these can account for anything up to 70 percent of the pattern. Broad tires – because of their greater susceptibility to aquaplaning – need more grooves and channels (about 50 percent more). These enable them to cope not only with high road surface temperatures due to the sun but also with dry, damp and wet surfaces, also at high speeds with the corresponding build-up of heat.Winter tires, on the other hand, not only have a deeper tread pattern but also wider grooves and sipes to allow snow to be packed into the tread and deliver extra traction power through snow-to-snow friction. Com-pared with summer tires, the tread bars of winter tires are softer and more pliable. This provides greater tire distortion when starting, braking and cornering, thus

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While all the well-known brand names in tire manufacturing have their own design departments and highly specialized profile developers to create the different shapes, dynamics and visual impact of the tread pattern, the Dutch tire maker Vredestein has gone a step further by collaborating with the famous Italian design firm of Fabrizio Giugiaro. And although for Vredestein/Giugi-aro the function of the tread pattern must always have top priori-ty, visual aspects come a close second.

a winning FormUlaFrom 0 to 100 km/h in 2.5 seconds – a huge challenge not just for the 910 horsepower engines of some of the Formula 1 racing cars. The rear tires of a Formula 1 car need to transfer this force and, at this acceleration to the track, preferably without wheelspin. Conversely, the front tires have a mammoth task to perform when braking flat out from 200 km/h to 0 within 1.9 seconds, because the weight of the vehicle shifts to the front during deceleration. This places a particular strain on the sidewall of the tire, which has to withstand immense forces. During full braking, the tire is subjected to a force of almost 2.5 metric tons.The tires are also put under enormous stress when cor-nering. At 150 km/h, centrifugal forces reach up to 3.2 g, which is more than three times the normal force of gravity. The tires must therefore be able to withstand cornering stability forces of 2.2 metric tons. Even when traveling in a straight line, tremendous forces are at work on the tires. At 350 km/h the high rotational speed of the 13-inch tires

exposes them to such enormous centrifugal forces that an unstable tread would warp. The tires are also pressed onto the track surface with a downforce of over a ton by the car’s spoilers and wings. The sidewalls in particular need to withstand this force, but without losing their suspension function. The suspension performance of the tire is determined by the carcass. In Formula 1 tires, the carcass forms an ellipse when viewed in cross-section. This gives the tires their typical balloon shape. Because of the very high torque, the tires must be able to deflect in order to swell the size of their footprint, thus improving traction and transmitting the propulsion forces ideally to the track surface. F1 tires are therefore only pumped up to a pressure of 1.1 bar (normal car tires: around 2.5 bar) using a nitrogen mixture that

does not heat up as much as air. As a result, it expands less.The belt of highly stable fibers such as Kevlar® or Rayon® that spans the tire underneath the tread in multiple layers and at different fiber angles is designed to prevent the tread from warping under pressure from the high centrifugal forces.The rubber compounds used for the tread are a well-kept trade secret. They need to be as soft as possible to ensure optimal grip – which is why an F1 tire usually only lasts a few hundred kilometers. To bring the tires rapidly up to the required temperature of around 100° C they are pre-warmed. This is because the particular rubber compound only performs as planned at these temperatures. For wet-weather tires the optimal temperature lies between 40 and 50 °C. It is therefore not surprising that they disintegrate on a dry track surface as they need water to cool down.

Full braking puts immense pressure on the front tires of F1 racing cars.

Tread paTTern design

Since 1998, F1 cars have to race on tires with four grooves in the tread.

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strengthening grip on wintry wet and icy road surfaces and preventing spinning. Another contributory factor to performance besides the intricate tread pattern and sipes are special rubber compounds with chemical ad-ditives such as silica and a high level of natural rubber in the tread that does not even harden in the cold.High-performance tires to suit both winter and summer conditions often have an asymmetrical arrangement of grooves and bars on the tread pattern. Rigid tread bars on the outer shoulders will increase cornering stabil-ity, whereas open structures on the less resilient inner shoulders will improve the absorption and dispersion of water. An asymmetrical design will also create fewer resonance vibrations and thus help to lower noise levels, while tires with a tread pattern for a specific roll-ing direction will reduce the danger of aquaplaning and increase grip on snow and ice.Off-roaders and highly popular sport utility vehicles (SUVs) will naturally need tires with their own special tread pattern. These are usually massive-bar tires to support driving on rough terrain.

Taking the strain Compared with the intricate lightweight tires for rac-ing bikes, the huge industrial tires needed for moving construction equipment or for transporters in the mining industry cannot be big and heavy enough. The largest tire in the world has a diameter of 4 meters and weighs a staggering 5.2 metric tons. On monster tires such as this from the factories of the Japanese manufacturer Bridgestone, heavy duty vehicles are able to transport loads of up to 365 metric tons. Every day the Michelin factory, too, in Lexington in the U.S. state of South Carolina turns out four-meter giant tires of rubber and steel. These huge tires, manufactured to a considerable extent by hand and made to measure for special earth-moving machines and ore transporters, pose engineers and chemists major challenges. The Michelin monsters from the U.S. Lexington plant contain up to 160 differ-ent ingredients and are customized to meet the specific requirements of the vehicles to which they are fitted. Taking into account the solidity and geological proper-ties of the bedrock, air temperature, weather conditions, incline/decline of the terrain and many other parameters, the rubber compound is adapted accordingly.

High-performance tiresIt is not only such specialist tires that are “made to measure”. During the development stage of a new car model, manufacturers of top-of-the-range automobiles issue tire makers with a list of precise requirements the tires are expected to meet if they are to be considered as original equipment suppliers (OEMs). As soon as the basic data of the future car have been established – factors such as weight, load carrying capacity, top speed, engine performance and geometry – the poten-tial tire suppliers begin their costly and elaborate R&D

Generally speaking, the market is divided into four application areas:

TRANSPORTATIONTransporting goods safely from one place to another over long distances at relatively high average speeds.

STACKING AND LIFTING Moving goods vertically, often within a very tight space, with safety and precision. This characteris-tically includes frequent steering movements and acceleration and braking maneuvers.

MULTI-PURPOSE TASKS (MPT = Multi Purpose Tires). Multi-purpose tires are for vehicles with different add-on equipment for road maintenance, winter maintenance or use in agriculture.

EARTH MOvING (EM = Earth-moving Machines). Wheel loaders, graders, v-dump cars and other vehicles that carry, load or distribute a wide range of different materials or transport those materials for further processing.Depending on the model – pneumatic tires, solid tires, MPT tires and EM tires – industrial tires have different properties and applications.

INDUSTRIAL TIRES offer a high level of driving comfort even on uneven surfaces and at relatively high speeds because of their method of

construction. Thanks to their radial design, they offer good operational performance, low rolling resistance and high traction.

SOLID TIRES are particularly effective for tough applications on paved surfaces for slow-moving or towed vehicles. They feature a very high load-bearing capacity and are primarily used for forklift trucks in all their varieties.

MPT TIRES demonstrate the particular capability that results from their structure in vehicles that have to achieve high speeds on roads and good traction on difficult terrain. Their radial design brings about high mileage and good traction and enables the required high speeds to be achieved.

DIAGONAL MPT TIRES on the other hand are particularly well protected against sidewall damage and provide effective

damping.

EM TIRES are characterized by a high resistance to damage and provide good traction on dangerous terrain.

HeavyweigHTs

Industrial tires of all sizes are sub-ject to the toughest conditions in day-to-day operation.


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Looking to the futureAnd these standards are set to rise. There will never be the perfect tire, but leading tire makers are steadily working their way towards the optimum. Their efforts are focused on further reducing rolling resistance (and thus fuel consumption), improving traction on wet surfaces, increasing the durability of the tire, lowering noise levels, improving the reliability of running on a flat tire, and reduc-ing the toxicity of the particulates (abrasion) through the use of harmless plasticizers and biodegradable fillers. In short: The tires of the future will be more economical, environmentally friendlier, safer and more “intelligent”.

work to define the tire’s needs. Based on a catalogue of detailed specifications and following diverse trials, the tire builders then set about developing the appropriate rubber compound. They rarely succeed immediately, which is why VW subsid-iary Audi proceeds with a series of iterative steps. This means that three months after starting development, the tire manufacturers deliver the first test tires based on the carmaker’s catalogue of specifications. Then, in comprehensive tests, the company’s tire experts will assess how far the specified criteria have been met. As a rule some weaknesses and failings will emerge at this point, perhaps the handling on dry surfaces or the rolling resistance. Usually the tire maker is allowed to make improvements twice in order to fulfill Audi’s requirement. But if a third attempt is unsuccessful, it is out of the running.

Elaborate trials Sports car maker Porsche employs a whole team of spe-cialized test drivers who have not only first-class driving skills, a wealth of experience and technical knowledge but also well-developed and highly sensitive hearing on which they can rely to detect critical noises. This is be-cause, apart from the behavior of the tires in aquaplan-ing, at high speeds, in snow, ice, cold and heat, or when suddenly overtaking, the noise they make plays a critical role in the assessment. A series of runs, each time with a new set of rapidly changed tires, are conducted always at the same speed over a variety of surfaces – slippery, rough, bumpy and normal – to compare the noise levels of the test tires against the reference tires. In this process, the subjective judgment of the tester is as important as the objective recordings made by the microphones attached to various points along the track. Frequently the driver is accompanied in the car by a “silent passenger” – a dummy with a plastic head and microphones in its ears to register the noise, which can later be evaluated. When the tires have completed all the tests and their strengths and weaknesses assessed, it is then up to the engineers and technicians to optimize the tires to the point where the critical test driver feels the high standards have been fully met.

Aquaplaning taking a left bend: good tires warn the driver of the danger ahead.

The measuring station in the car is linked to receivers along the testing track.

TaKing oFF

For the Airbus A380, Michelin and Bridgestone have developed radial ply tires. Each of the 22 tires on an Airbus 380 must be able to bear at least 33 metric tons and withstand temperatures of 120º C during take-off, only to be cooled to minus 50º C just a short time later. On landing, the aircraft tires are com-pressed to a third of their normal volume, despite the tire pressure of 18 bar, and accelerated to 250 km/h within the space of a few meters.

The debate over reducing CO2 emissions in road traffic has long since reached the tire industry and its suppliers. And for good reason. According to the calculations of leading tire makers such as Continental and Michelin, the rolling resistance of tires accounts for some 20 percent of fuel consumption. Indeed, in city traffic this figure can rise to as high as 30 percent. Rolling resistance occurs through the tire deforming to produce as much contact as possible with the surface of the road: Every time the tire revolves and cushions on the ground it absorbs energy which is converted into heat and released into the atmosphere.While automobile manufacturers are focusing on curbing the car engine’s thirst for fuel and on minimiz-ing the emission of environmentally harmful exhaust – with techniques ranging from direct gas injection, more efficient fuel combustion, electronic manage-ment of the engine to hybrid drive, a combination of the combustion and electro-engine – tire makers have been concentrating their efforts on reducing rolling resistance and improving ways of monitoring tire pres-

sure. If air pressure drops by as little as 0.3 bar below the mark recommended by manufacturers, the vehicle will consume around 1.5 percent more fuel. This is the result of rolling resistance increasing by some six percent. In a standard-size automobile this adds some 16 liters to its annual fuel consumption. The tire maker Continental has calculated that such an increase raises a car’s emissions of environmentally harmful CO2 by as much as 38 kilograms per annum.

Fatal connectionAt first glance, this may not appear particularly impres-sive. However, if we relate this statistic to the 33 per-cent or so of cars in Germany alone (15.2 million) that drive on under-inflated tires, then CO2 emissions add up to an annual level of more than 600,000 metric tons. These statistics are calculated on the basis of an automobile with a consumption of 7.5 liters of fuel per 100 kilometers and an annual mileage of around 15,000 kilometers. The fatal effect of insufficient air pressure in generating

For the sake of the environment

GREEN TIRES

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For the sake of the environment

Tires can make a valuable contribution to reducing damage to the environment through automobiles.

although drivers may check oil and water levels when stopping off at the filling station for fuel, they rarely think of examining the air pressure in their tires. For this reason, leading tire makers such as Continental are working on a new generation of tires with an elec-tronic tire pressure monitoring system. Fitted to the inner side of the tread of these “intel-ligent” tires are sensor modules weighing just a few grams, which connect up to the vehicle’s electron-ics. These highly sensitive “passengers” transmit all relevant data about the tire type, air pressure, speed and load index to the on-board computer so that as-sist systems such as ABS (Anti-Blocking System) and ESP (Electronic Stability Program) can function more effectively. It is estimated that, once in operation, the braking distance of a vehicle traveling at a speed of 100 km/h could be shortened by up to a meter. In future, an on-board computer will feed data on wheel and axle load distribution into the microchips of ABS and ESP at the commencement of every journey and thus make driving safer and more comfortable. Also,

excessive levels of environmentally harmful exhaust emissions can be illustrated by figures issued by the European Union: They show that if an automobile’s tire is under-inflated by just 0.5 bar, CO2 emissions will rise by as much 140 kilograms in one year.In the specific case of utility vehicles, potential savings on fuel consumption and CO2 emissions are even more drastic when tires are inflated to the optimum level of air pressure. Such are the findings of experts at the tire manufacturer Continental. In a study based on the U.S. market they found that on average utility ve-hicle tires were under-inflated by some twelve percent. This causes excess fuel consumption of approximately four billion liters of diesel per year. And, in turn, this leads to unnecessary CO2 emissions of more than nine billion metric tons.

The “intelligent” tireRegular checks on the tire’s air pressure not only reduce avoidable levels of CO2 emissions: they also save the vehicle owner money. However, it seems that

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the time is not far off when drivers can expect to be addressed directly by their tires when setting off and ending their journey and told to adjust inflation pres-sure after loading and unloading the vehicle. This will lower fuel consumption and reduce CO2 emissions. Yet another feature of the new generation of Continental’s tire pressure monitoring system is an integral load sen-sor on each wheel which checks the load on the tire and sounds the alarm when, for instance, the cargo in a truck has become displaced. This new technology is expected to be ready for launching in 2009.

Environmentally friendly compoundsHowever, there are already tire pressure monitoring systems in operation. They are usually fitted to the valve and raise the alarm at as little as 0.2 bar under-inflation or drop in pressure so that the driver can

respond promptly and top up the tire with air.Tire makers still see the greatest potential for protect-ing the environment and minimizing fuel consumption in optimized rubber compounds and in modifications to the structure of the tire. A key part here is played not only by the intelligent use of silica as filler and finely balanced mixtures of different kinds of rubber but also the design of the tire’s tread, the composition of the belt and the carcass. Although the past 15 years have seen leading tire manufacturers reduce rolling resistance by as much as 30 percent, researchers still see plenty of scope for further progress. Tire manufac-turers have set their sights on reductions of up to 50 percent over the next 25 to 30 years. This would be a major step towards lowering the amount of harmful gases released into the atmosphere, as fuel consump-tion caused by rolling resistance would be halved in the process – from the current rate of approximately every fourth tank of fuel to every eighth.

Enormous savings potentialAll of this assumes, of course, that the automobile buyer opts for low-rolling-resistance tires in the first place. Taking just the high-tech tires already available on the market, then globally some 50 million metric tons of CO2 could be prevented – that’s the equivalent of the entire level of annual CO2 emissions in Sweden – if the 800 million registered vehicles were fitted with low-rolling-resistance tires. Tire maker Michelin has calculated that if the trucks and automobiles in Europe alone were to run on “green” tires, there could be an annual saving of 4.5 billion liters of diesel and 1.5 bil-lion liters of gasoline. That would mean a reduction in CO2 emissions of around 15 million metric tons. The difference in quality of tire material currently on offer is considerable. According to a survey by the German motoring association ADAC, the rolling resistance of tires on one and the same automobile can vary by as much as 50 percent.This is even truer of trucks. Continental, for example, has been able to reduce rolling resistance by a further eight percent with its latest generation of truck tires. As a result, CO2 emissions from a typical semi-trailer operating in traffic across Europe have dropped in one year by as much as up to three metric tons.In order to be able to meet the EU’s future limits on CO2 emissions from motor vehicles, car makers, their suppliers and – last but not least – their sources from the chemical industry need to work hand in hand. It is their common objective to guarantee people’s con-tinued mobility without major restrictions and, at the same time, to keep within limits the growing threat of global warming and the potentially catastrophic effects on our climate. This is where tires and their chemical composition have a role to play.

GREEN TIRES

Environmentally awareThe hybrid engine, correct tire pressure and the right mix of rubber compounds for the tread all play their part in reducing the car’s fuel consumption as well as its CO2 emissions and thereby help it to pro-tect the environment.

Tires of the future will be leaving a trail of green behind them as they help protect our climate.

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RUBRIK

Keeping global warm-ing under control pro-vides a challenge to the rubber and tire industry.

Whether in the laboratory, in pro-duction or during transport – safety and quality have top priority.

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High standards worldwideother words, it takes in the entire supply chain across department boundaries and has two main aims: • To identify and meet customer requirements• To consistently improve the quality

of products and services.Environment management to ISO 14001 focuses on two key goals: • Compliance with the laws and regulations• Improvement of the environmental performance.Quality and safety management at LANXESS is based on developments, experiences and systems that have been built up and perfected over the course of de-cades. After the introduction of the ISO 9000 series at the start of the 1990s at various rubber producers in Europe, America and Asia, the then Rubber Busi-ness Group of Bayer AG was also certified in 1994. As part of the quality management systems, all em-ployees were familiarized with topics such as “Con-tinuous Improvement Process”, “Plan-Do-Check-Act” and “Target Management”, and integrated into the process by means of intensive training and discus-sions in quality circles.

Optimized process controlWith the transition from Bayer to LANXESS, the high quality standards were adopted and introduced glob-ally. Over the course of 2008, all sites – including those in China – will be certified to the ISO standards.Systematic quality and safety management is based on a method of sophisticated process monitoring and statistical process control (SPC), which facilitates the manufacture of products to consistently high quality

Every employee at LANXESS is responsible for safety in the production process and for product quality. However, some have more responsibility than others. Dr. Werner Breuers is the member of the Board of Management responsible for Group-wide quality and safety management (HSEQ = Health, Safety, Environ-ment, Quality). Under his leadership, the Board has formulated ten guidelines that make up the Quality and Environmental Policy of the company (see page 90).

Diverse management tasksHSEQ officers in each of the business units are responsible for the daily implementation and continu-ous improvement of these guidelines on all levels and at all sites. They organize staff training focusing on quality and safety, monitor worldwide certification to ISO 9001 (quality) and ISO 14001 (environment management), develop guidelines and manuals for production and service workflows, arrange regular audits, ensure that processes are consistently geared towards customer requirements and develop reliable procedures for handling customer complaints. Finally, they cooperate closely with the responsible resident authorities to ensure that purely local regulations are included in the safety system and that rescue actions are coordinated smoothly if an accident should occur despite all the safety precautions.

Long-time experienceQuality management at LANXESS in accordance with ISO 9001 is based on company processes. In

QUALITY AND SAFETY

Certification

In 2008 LANXESS’s Chinese production sites became the last of the company’s locations to be certified under ISO 9001 (Quality Management) and ISO 14001 (Environ-mental Management). This means that the same high standards apply worldwide, thereby not only increasing safety for employees and the envi-ronment but also boosting customer satisfaction.

company to filter out and rectify recurring faults. The process encompasses technical, organizational and logistical customer complaints. Learning from mis-takes and rectifying them as quickly as possible is the basis used to check the cause of errors and devise solutions. This can be done, for example, by making internal comparisons through “best practices”.

Monitoring and rapid supportBased on the principle of “reciprocal monitoring, mutual support”, full-time and part-time internal audi-tors perform regular inspections at all LANXESS sites around the world to check whether the regulations are being observed, whether the standards meet the specifications, and whether the technical equipment and test and measuring devices comply with the ap-plicable regulations.Suppliers are also subjected to random checks by LANXESS employees. It is vital that employees are kept aware of the im-portance of quality and safety. To this end, they are given regular training focusing on safety and quality, and familiarized with the latest information from other areas of the company in line with the “best practice” principle. The courses deal with quality, handling

standards. New technologies help maintain and fur-ther develop these high quality standards. Optimized process control, improved measuring systems and intelligent software make it possible to dispense with many complex tests on the raw polymer, blends and vulcanizates, as the process rules out the possibility of exceeding defined safety limits. Online methods of analysis that facilitate fast process control shape production activities these days. For example, during the hydrogenation of NBR to Therban®, the residual double bonds important in the end product can be tracked via online spectroscopy. However, the single most important corrective is always the customer. Customer satisfaction analyses are performed regu-larly with the help of external experts. The results are evaluated carefully. If weak points are discovered, the causes are analyzed and remedied as quickly as pos-sible through corrective measures.

Learning from complaintsComplaints are also a key element in LANXESS’s quality assurance process. The management of the company channels all complaints to a central point, where they are evaluated before being forwarded to the area responsible. This central analysis allows the

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Performance test

THis is wHaT we sTand for

1. LANXESS is a progressive, dynamic and future-oriented company. To this end, we set ourselves clear goals that we make known to all employees. Improvements and performance are measured and evaluated and the results are published.2. We see our employees as the source of added value and creativity in our company and support their

commitment to achieving improve-ments. We provide motivation for continuing education and use information and training to foster awareness of safety, health, the environment and quality.3. We respect social standards and values. We view personal integrity and mutual respect as basic principles of our corporate culture.

4. We employ the principles of Responsible Care® and sustainable development to safeguard employees, the environment and society. At LANXESS, environmental protection, health, safety and quality are accorded the same priority as commercial efficiency.5. Our products, services and actions reflect our commitment to quality and we see this as an integrated approach to corporate quality which takes into account the interests of employees, customers, suppliers, owners, neighbors and society. 6. We are a reliable, competent partner for our customers, recogniz-ing their expectations early on, responding rapidly to their needs, and thereby continuously enhancing their satisfaction.7. We consider our suppliers and service providers to be partners and select them on the basis of their expertise and reliability and also their compliance with our ethical corporate principles.8. We are committed to comprehen-sive environmental protection and maximum safety. To achieve this, we develop environmentally friendly products and minimize environmental impact to continually enhance our environmental performance. We report publicly on our progress.

9. We create trust in our corporate activities through open and respectful dialog with our customers, employ-ees, suppliers, owners, authorities and the public and provide the necessary information.10. Throughout the world, we use a process-oriented, integrated management system that complies with the international ISO 9001 and ISO 14001 standards on quality and environmental management to constantly enhance our performance and achieve our goals effectively.

The quality and properties of new products and prod-uct variants are tested in an in-house test laboratory (page 38).

A sense of responsibili-ty for health, safety, en-vironment and quality.

Quality and safety are fundamental

QUALITY AND SAFETY

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quality and safety standards is really based on nothing more than basic common sense, i.e.:• Making the product that the customer expects.• Working to the complete satisfaction of the cus-

tomer.• Not making mistakes because mistakes cost money.• If a mistake does occur, making sure that it does not

happen again.• Checking and improving regular processes.• Assigning sufficient staff and an adequate budget to

ensure that processes run smoothly.By keeping these six “golden rules” in mind at all times, employees can help to eliminate risks, avoid mistakes and keep customers satisfied.

hazardous substances and occupational health and safety. They also focus on basic everyday precautions that tend to be taken for granted, such as protective clothing, the mandatory use of hardhats or the em-ployment of respiratory masks during cleaning work.This helps to increase employees’ awareness of the importance of apparently “banal” rules.

Six “golden rules”The quality managers from all sites meet on a quar-terly basis to exchange information on new process technologies and organizational measures and to draw up correction mechanisms for weak points that have been discovered in the processes. All quality and safety concepts are subject to con-tinuous evaluation. This also applies to emergency response plans and cooperation with authorities and the emergency services. That’s why regular exercises are held with the fire department or in cooperation with agencies for water pollution control. Workshops held in cooperation with representatives from the employers’ accident liability insurance association are designed to enhance safety awareness among LANXESS employees.The full-time and part-time quality and safety manag-ers are always keen to point out that performing to

Fastidious quality con-trols assure customer satisfaction.

Dress code

Issues that should in fact be obvious such as the need to wear protective clothing and goggles need to be brought up again and again.

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Symbols made of rubber When Cologne-based artist Eva Ohlow designs ob-jects from rubber using a knife, steel wool, anti-aging agents and caustic acid, and then dyes the shapes, geometric forms and symbols with carbon black, red iron oxide and chalk, she ends up with artworks that resemble damaged, tattooed skin. In fact, Eva Ohlow has indeed taken her inspiration from living sources: “They are based on tattoos from the Congo, although the dye they use there contains natural poisons that act as a vaccine,” she explains.During several visits to Central Africa she observed the rituals and cults of communities still leading an ancient way of life. As part of an art project she spent some time in Togo, where she acquainted herself with cult figures and symbols. She also studied the semantic terms in different languages that describe diametric poles of life, such as masculine - feminine, soul - body, beginning - end.

A bridge between nature and technologyThe history of the exploitation and ill treatment of the indigenous people under colonization during the reign of the Belgian King Leopold II and the millions of lives it cost are reflected in the artist’s works: wrinkled, damaged, pressed and vulcanized at a temperature of 160° C, her rubber mats symbolize maltreated hu-man skin. Eva Ohlow associates skin – as the body’s protective covering and most sensitive organ – with the opposites of life and death. The artist uses rubber to build a bridge between

nature and technology. Her artistically structured pat-terns and pictures made of rubber symbolize the dam-age done to the rubber tree by cutting into it to extract its “milk”. In an industrial process this latex is flexed and kneaded together with carbon black and other additives until the molecules have blended and are ready for further processing. Eva Ohlow sees in her artistic transformation of such badly treated material a way of giving the industrial product a new dignity. After vulcanization, the artist’s work continues: now the object is “maltreated” by means of human energy, chemical processes and hard tools. Symbols are en-graved and pigments added that change under ultra-violet rays – differently in water than in dry air. “In an observant and interventionist way, Eva Ohlow applies alchemy that makes magic plaques out of steel and memorials out of rubber mats,” writes art historian Wibke von Bonin. Eva Ohlow has presented her works at a number of exhibitions, the most recent being the show “Volcano – Mit geballter Kraft und Hitze verschmolzen” at the former Vulkan rubber factory, now an art center, in Cologne.

The artist Eva Ohlow hand- ing over her work “Vol-cano”, which was bought by LANXESS, to Günther Weymans, head of the Technical Rubber Products business unit.

The artist Eva Ohlow

Earth vibrations 1997 – approx. 124 x 124 cm

ARTWORKS

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VulcanoThis work of art produced in 2001 (12 x 45 x 30 cm) now belongs to the collection of LANXESS’s Technical Rubber Products business unit.All objects and pictures made of pigmented, vulcanized, processed rubber.

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RUBRIK

Lava stream 2007 – Object approx. 50 x 35 x 40 cm

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Magma2000 – approx. 124 x 124 cm

Birth of a volcano III2000 – approx. 124 x 124 cm

Eruption III2000 – approx. 124 x 124 cm

Eruption I-IV1999 each approx. 124 x 124 cm

ARTWORKS

MASTHEAD / PICTURE CREDITS

96

Picture credits

MastheadPUBLISHER LANXESS AG, Leverkusen

PROJECT MANAGEMENT Corporate Communications – Udo Erbstößer, LANXESS AG, Leverkusen

PROJECT TEAM Marketing Technical Rubber Products – Rodrigo HenriquezScientific consultant – Dr. Martin MezgerMarket Communications – Michael Fahrig,LANXESS Deutschland GmbH, Leverkusen

CONCEPT/TEXTS PSC – Presse Service & Consulting GmbH, Munich

ART DIRECTOR Sascha Carl

ILLUSTRATIONS & IMAGINGTim Möller, Andreas Schmidt-Rabenau, André Kirsch

PICTURE EDITING Sophie Henkelmann

FINAL EDITINGBirte Kaiser

PRINTING & LITHOGRAPHY Peschke Druck, Munich

This information and our technical advice - whether verbal, in writing or by way of trials - are given in good faith but without warranty, and this also applies where proprietary rights of third parties are involved. Our advice does not release you from the obligation to verify the informa-tion currently provided - especially that contained in our safety data and technical information sheets - and to test our products as to their suitability for the intended processes and uses. The application, use and processing of our products and the products manufactured by you on the basis of our technical advice are beyond our control and, therefore, entirely your own responsibility. Our products are sold in accordance with the current version of our General Conditions of Sale and Delivery.

TITLE: Thorsten Martin for LANXESS

CONTENTS 3:Shutterstock (2), LANXESS (6), Tom Kirkpatrick, Getty Images (2), Porsche; Illustration: Tim Möller

GLOBAL ELASTOMER MARKET 4–9:Illustration: Tim Möller, Sascha Carl, LANXESS (8)

THE TEARS OF THE CA-OU-TCHOUC 10–19:Agenda/Michael Kottmeier, Shutterstock, AKG (4), Interfoto, Ullstein Bild (5), John Loadman, www.bouncing-balls.com, Corbis (5), Anti-Slavery International, Bayer AG (2), Tom Kirkpatrick, Museu Paulista de Universidade de São Paulo (2), BPK (2)

A YOUNG COMPANY WITH STRONG ROOTS 20–24:Ullstein Bild, BPK, LANXESS (17)

GOOD CHEMISTRY 25:Tom Kirkpatrick

ONE INNOVATION LEADS TO ANOTHER 26–31:LANXESS (15), Freelens Pool, dpa (3) , ContiTech

MASTER OF VERSATILITY 32–37:LANXESS (11), Getty Images, Helimax: by kind permission of Nölle Industrielle Umwelttechnik GmbH, Shutterstock, Laif

PULLING, PRESSING, TEARING 38–41:LANXESS/Thorsten Martin (18), Tom Kirkpatrick

THE UNSEEN ALL-ROUNDERS 42–45:Shutterstock (2), Getty Images (3), Vulkan, Jürgen Mainx, LANXESS, ContiTech (2),

RELIABLE SEALING ELEMENTS 46–53:Laif, Sinopictures/CNS, Imagechina/Lin Xin tj, Freelens Pool, Börger Pumpen, Seepex, Getty Images (3), LANXESS (5), Klaus Vollrath, Blickwinkel, Graf-Dichtungen, Corbis (2), Volkswagen, ContiTech (3), API Schmidt-Bretten (1), Keystone, Tom Kirkpat-rick, Illustration: Tim Möller

THERE IS POWER IN SILENCE 54–61:Imagebank/Jorg Gruel, Shutterstock, Huaiwei, Gerb, Getty Im-ages, ContiTech (11), Xinhua/Das Fotoarchiv, EB-Stock, Mercedes Benz, Vulkan, F1-Online, Mageba

ON THE MOVE 62–65:Getty Images (2), Shutterstock, LANXESS, Still, YPS Collection, ContiTech (2)

THE DRIVING FORCE 66–69:Jürgen Mainx, Duell, LANXESS (4), dpa, Illustration: Tim Möller (3)

FLEXIBLE AND ADAPTABLE 70–73:Mauritius, Shutterstock, Getty Images, ContiTech (3), Laif, Dr. Ing. h.c. F. Porsche AG

MADE-TO-MEASURE INNOVATIONS 74–75:LANXESS (3), Shutterstock (2), Nikon, Michelin, Audi

THE LEGS OF THE CAR 76–83:Getty Images (6), Continental AG (5), Corbis (3), dpa (2), Vredes-tein-Giugiaro (3), Michelin (6), Porsche (2), Shutterstock, Ralph Bohle GmbH, Bridgestone, Dieter Röscheisen, Airbus, Till Bartels

FOR THE SAKE OF THE ENVIRONMENT 84–87:Shutterstock (3), Getty Images

HIGH STANDARDS WORLDWIDE 88–91:LANXESS (5), F1-Online

SYMBOLS MADE OF RUBBER 92–95: LANXESS (all)

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