polyurethane chemistry and - wwdpi · polyurethane chemistry and products: ... 1960’s development...

4/4/2013

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Polyurethane Chemistry and Products:Past, Present and Future

Dr. Xudong FengExecutive DirectorExecutive Director

Institute For Molecular EngineeringUniversity of Chicago

Agenda

• Polyurethane Chemistry Introduction

• Applications – Chemistry and Socioeconomic Impact

• Innovation in PU Chemistry

• Polyurethane (Isocyanate) Emissions and DegradationDegradation

• Health and Safety Considerations

• Summary

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Introduction

UrethaneIsocyanate Alcohol

AmineIsocyanate Water CO2 gas

Otto BayerDR Patent 11.11.1937

UreaIsocyanate Amine

Commercial Isocyanates in the Polyurethane Industry

• Aromatic– TDI MDI MonomersTDI, MDI Monomers– pMDI (polymeric MDI)

• AliphaticHDI IPDI H MDI– HDI, IPDI, H12MDI Monomers

– HDI and IPDI homopolymers

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Isocyanate Reaction Pathways

Uretdione“Dimer”

RNHCOOR’

RNHCO

Allophanate

RNCO

NO O

R‐NCO

(RNHCOOH)

H2O

OCN‐R‐N=C=N‐RNCO

Carbodiimide

Uretonimine

RNHCOOR’Urethane

R’OH

R‐NCO

IsocyanurateTrimer

Allophanate

RNCO

NO O

(RNHCOOH)

RNH2 + CO2

RNHCONHRUrea

RNHCONHR’Urea

RNHCONHR’

RNHCOBiuret

R‐NCORHHCOR’ + CO2

Amide

Monomeric Diisocyanate Relative Reactivity

Isocyanate k1 k2

TDI 400 33TDI 400 33

MDI 320 110

HDI 1 0.50

H12MDI 0.57 0.40

IPDI 0.62 0.23

OCN R NCOHO R'

OCN R NCO

OH

R'HO R"

R" OC

N

O

RH

NH

CO

O

R'k1 k2

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Relative volatility of isocyanate types

• HDI Isocyanurate trimer 0.00052• HDI Biuret 0.93• Monomeric MDI 1• Polymeric MDI 1• H12MDI diisocyanate 1• IPDI diisocyanate 48• HDI diisocyanate 1,100• TDI diisocyanate 2,500y ,• Water 1,800,000• Solvent (methyl ethyl ketone) 9,100,000• Methyl isocyanate 34,800,000

Polymeric MDI Composition

50% PURE

TARS ETC.

2,4’

4,4’

HIGH FUNCTIONALITY SPECIES

Diisocyanate

Triisocyanate

2 3 4 5 6 7 8 9 Others

POLYMERIC MDI IS A MIXTURE OF ISOMERS AND OLIGOMERS WITH ANAVERAGE FUNCTIONALITY OF 2.7 AND 31.5% NCO GROUPS

FUNCTIONALITY

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Polymeric Aliphatic Isocyanates

NH

(CH2)6 NCO

N (CH ) NCON(CH2)6OCN

O

NH

(CH2)6 NCOO

(CH2)6OCN

(CH2)6

NCO

(CH2)6 NCON

N

N

O

OO N

O

N

O

N O

(CH2)6-NCO

(CH2)6OCN

(CH2)6OCN

Asymmetric Trimer

(CH 2)6 NCOOCN

HDI

Biuret

Trimer Isocyanurate Iminooxadiazindione

NH

(CH2)6 NCON(CH2)6OCN

OO

O

R

Allophanate

N N

O

O

(CH2)6(CH2)6 NCOOCN

Dimer Uretdione

Aliphatic Polyisocyanate Oligomers

Trimer (n=3) Typical Oligomer Breakdown

Pentamer (n=5)

Heptamer (n=7)

n = 1 <0.01%n = 3 ~ 50%n = 5 ~ 20%n = 7 ~ 10%n = 9 ~ 6%n = >9 ~ 14%n = oligomer #

*Product contains fractions of trimers, pentamers, heptamers, and higher oligomers.

N N

NOR

O

(C H2)6O

RN N

N OR

O

OR

Pentamer

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Chemistry introductionUnparalleled Versatility and Utility

NN

O

O

O

O

Segmentation: Chemistry is the key !• Hard and soft segments

P l l t i t lliHN

HN OO

HN

HN

O

O

O

OHydrogen bonding inUrethane Linkages:

• acts as non‐covalent “crosslinking”•Vital to good elastomeric properties

• Polyols to give crystalline oramorphous properties

Soft segment Hard segment

Agenda






• Summary

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Polyurethane Application Versatility74.968.662.456.2

1.2

1.11.00 9

SealantsC.A.S.EC.A.S.E

49.943.737.431.225.018.712.56.25.65.04.43.73 1

Density, lbs/ft 3

0.90.80.70.60.50.40.30.20.10.090.080 07

Specific Gravity, gm

s/cc

FoamFoam

3.12.51.91.30.6

0.070.060.050.040.030.020.01

0 10 20 30 40 50 60 70 80 90 40 50 60 70 80

Shore A Hardness Shore D Hardness

Polyurethane Foam Cell Formation

BUBBLES GROW BUT DONOT TOUCH AT THIS STAGE THE PU IS MICROCELLULAR

BUBBLES TOUCH TO FORM

CO2

CARBON DIOXIDE SEPARATESFROM REACTING PHASE AND DIFFUSES INTO NUCLEATION

POINTS

THE PU IS MICROCELLULAR TO FORMCELL WINDOWS

CLOSED

CLOSED CELL FOAM

CO2 CO2

MIXED LIQUIDSWITH

NUCLEATING AIR

INTERCONNECTING LABYRINTH

CLOSED CELL

OPEN CELL FOAM

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Rigid PU Foam Chemistry

• Polyols– Low MW– High Functionality

• pMDI – highly branched• Structure

– Highly crosslinked– Rigid– Small closed cell traps gases– Thermal insulation

Flexible PU Foam Chemistry• Polyether Polyols

– Vary MW and functionality• TDI diisocyanateTDI diisocyanate

– Lower crosslink density than rigid• Water reaction produces Carbon Dioxide as

the principle method of expanding the foam • Additives controls

– Reactivity– Cell size and breathability– Flammability– Color

• High Resiliency Foam – Memory Foam– Hybrid of Rigid and Flexible

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Coatings TechnologyWide Variety of application techniques and markets

Solventborne Waterborne100% solids

1 Component‐Moisture cure‐Blocked Iso

2 Component‐Polyol‐Crosslinker

2 Component‐Polyol/urea‐Crosslinker

2 Component‐PolyurethaneDispersion

‐Crosslinker

1 Component‐PolyurethaneDispersion

Crosslinking improves propertiesCrosslinking improves propertiesAbrasionChemicalWeatheringStrength

Thermoplastic Polyurethane (TPU)

Aliphatic I t

Aromatic I t

Non-yellowingUV resistance

Polyether

IsocyanateIsocyanate

Polyester

UV resistance

• Cut & Scratch Resistance• Superior Wear Resistance

• Hydrolysis Resistance• Fungus & Moisture Resistance

• Higher Mechanical Properties• Fuel & Oil Resistance • Heat Stability• Better Inherent UV Stability

• Cold Temperature Flexibility • Resistant to Salt Water Cracking • Ozone Resistance• Better Transparency

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Socioeconomic Impact of Polyurethanes in the US*

• The PU Industry directly generates $19.7 B in output and 37,700 jobsoutput and 37,700 jobs

• Multiplier effect impacts jobs and output in downstream industries:• Additionally, the PU industry indirectlysupports $40.1 B in output and 165,000 jobs

• In total: $59.9 B in output and 202,600 jobs$ p , j• PU products are used in industries generating $245.5 B in output and employing nearly 1 million workers

*”The Economic Impact of the Polyurethane Industry in 2010”, Economics & Statistics Department of the American Chemistry Council

Agenda






• Summary

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Historical Development: Isocyanates and Polyurethane Technologies

1930’s Isocyanates/urethanes developed by Otto Bayer 1940’s Addition to alkyds to improve quality/productivity1950’s Commercialization of Flexible Foam (TDI/Polyester)1960’s Development of aliphatic polyurethane coatings

PMDI for rigid foams1970’s Aqueous polyurethane dispersions (PUDs)

Elastomers, Footwear, High Resilience Flex FoamUrethane acrylate resins

1980’s Two component (2K) urethane coatingsSpray foam building insulationAutomotive energy absorption for passenger safetyAutomotive energy absorption for passenger safety

1990’s 2K waterborne coatingsHydrophilic polyisocyanates and functional PUDsCommercialization of visco-elastic memory foamRadiation curable PUDs

2000’s 2K WB PUR with excellent chemical resistanceCo-solvent free PUD/acrylic dispersions

Rigid PUR / PIR Insulation Foams Innovation Drivers

“PolyIso”Growth

HCFCsHFCs HCs

HFOs

“Microcell”

PolyIso

“Polyurethane”Low “ODP”

No “ODP”

Page 22

1960 20121980 2000Oil EmbargoEPCAOzone DepletionFlammability Stds.

Montreal ProtocolNAECA / CAAEnergy StandardsCodes

HCFCs

Energy StandardsCodes“Green” Stds. / CodesGHG concerns

CFCs

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Innovation Driver in Coatings Applications

N

ON

N

NO

O O

OCN

H

N SO3 NR3H

owth O

OOUrethaneacrylate

Ionic hydrophilic trimer

N N

N OO

OR

R

R

NCO

NCOOCNN N

O

O

RR NCOOCN

ROCN N CO

CO

O

NH

R

R'

NCO

OCN

O O O

Gro

UretdionTrimer

Allophanate

R O C NH

R'n

1960 2010

NH

O

O R' O

O

NH

R NH

O

nO

OCN – R – N – CO – N – R – NCO

CO – N – R – NCOH

H

Biuret

Polyurethanes ‐ Dispersions/Prepolymers

Enable Waterborne system

Agenda






• Summary

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Polyurethane Application/Use Considerations‐ Aerosolizing

• Processes involve spray applications (e.g., foam and coatings) can generate airbornefoam and coatings) can generate airborne monomeric and polymeric isocyanate aerosols

• Monomeric isocyanate vapor pressures influence potential airborne concentrations: ‐ the more volatile isocyanate monomers (e.g., TDI

and HDI) have a greater potential to release airborne concentrations than the less volatile isocyanate monomers (e.g., MDI and H12MDI)

• Releases of airborne isocyanate can occur when a polyurethane product is thermally degraded

Polyurethane Application/Use Considerations– Thermal Degradation

• Polyurethane, like all organic material, will burn when supplied with sufficient heat and air

• When a fire occurs the gases produced depend upon the temperature, the amount of oxygen and some catalytic effects.

• In a fire situation typical off‐gases of PUR include:– Carbon dioxide, carbon monoxide and carbon (soot)– Water– Nitrogen oxides (NO2, N2O, N2O5) commonly referred to as NOx– Hydrogen cyanide– Isocyanates

• Other plastics and wood emit similar gases when burned

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Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases*

• Toxic effluents in fires are influenced by multiple factors.

• Combustible materials (synthetic or man made) generally• Combustible materials (synthetic or man‐made) generally produce toxic products when burned.

• Carbon monoxide is the most prevalent and abundant toxicant in fires involving natural products and synthetic materials under most combustion conditions.

• The acute toxicity of natural and synthetic materials e acute to c ty o atu a a d sy t et c ate a s(including polyurethanes) appears to be more similar than different.

* Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases. T. Landry, J. Pauluhn, D. Daems, K. Reimann. International Isocyanate Institute.

Thermal Degradation of Car Paintin Body Shop Repair*

• Generation of airborne isocyanates was identified during cutting, grinding, and sanding operations in Body Repair Shops

• Highest levels of airborne

Grind

ing

isocyanates were seen during the cutting process Cutting

*Boutin, M., Dufresne, A., Ostiguy, C., Lesage J. Determination of Airborne Isocyanates Generated During the Thermal Degradation of Car Paint in Body Repair Shops . Annals of Occupational Hygiene, vol. 50, no 4, 2006, p. 385‐393.

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Agenda




• Polyurethane Emission and Degradation ToxicityToxicity


• Summary

Relative volatility of isocyanate types

• HDI Isocyanurate trimer 0.00052• HDI Biuret 0.93• Monomeric MDI 1• Polymeric MDI 1• H12MDI diisocyanate 1• IPDI diisocyanate 48• HDI diisocyanate 1,100• TDI diisocyanate 2,500y ,• Water 1,800,000• Solvent (methyl ethyl ketone) 9,100,000• Methyl isocyanate 34,800,000

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Health and Safety Considerations• Exposure Routes

– Inhalation, Dermal, Eye, Ingestion

• Hazard communication– MSDS and Label Review– Safe Use & Handling Literature Review– Workplace Training

• Best Practices: – Routine Air Monitoring – Appropriately designed ventilation; particularly local exhaust pp p y g ; p y

ventilation – Proper use of personal protective equipment (PPE)– Effective workplace practices or housekeeping standards– Medical Surveilance

Agenda






• Summary

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Summary

• PUR chemistry offers versatility and unique properties to meet various application requirements

• PUR chemistry contributes to sustainability by directly impacting reduced energy usage and solvent levels, while extending product life

• Similar to other chemicals, isocyanates used in the polyurethanes industry are reactive chemicals that need to be handled in a safe manner. Such that:– There is a need for appropriately designed ventilation, proper

use of personal protective equipment (PPE), and effective workplace practices/housekeeping standards

– Safe use and handling of isocyanates should be achieved in accordance with the principals of Product Stewardship and Best Industry Practices.

Backup

4/4/2013

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Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases

Thermoplastic Polyurethane (TPU)

Raw Materials: HO\/\/\/\/\/OH + OCN - R - NCO + HO\/\/\OH

Polyol Diisocyanate Chain Extender

TPU is a multi-phase block-copolymer made from three raw materials:

Polyol Diisocyanate Chain Extender

MultiphaseD i St t

/\/\/\/\/\/ \/\/\/\/\/ \/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ /\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\

Polymer Block:

O O O OII II II II

- CHN - R - NHC - O\/\/\/\/\/O - CNH - R - NHC - O\/\/\O -n

Soft segment Hard segment

Domain Structure: /\/\ /\/\/\/\/\/\/\/\/ /\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\

HS-Crystallite

Hard Segment: Imparts rigidity, hardness, & flexural modulus characteristics and determines the upper use of temperature.

Soft Segment: Imparts elasticity, flexibility & resilience and determines the low temperature performance.

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2K Solventborne CoreactantsCoreactants typically make up a majority of the polyurethane resin systemStrongly influencing modulus, Tg, elasticity, VOC

• Acrylics– Fast physical dry– Low iso demand– UV resistance

• Polyesters– Chemical Resistance– Versatile chemistry

UV i t

• Polyethers– Low cost– Hydrolytic stability– High Solids

• Polyaspartates– Weatherable– High Solids

Hi h P d ti it– UV resistance – High Productivity

• Polyamines– Rapid cure– High Solids– Chain extender

2K Solventborne Crosslinkers

HDI PolyisocyanateBiuretBiuret

Low MWBiuret

Low MWBiuret

High MWTrimer

High MWTrimer

Fast Drying

IPDI Polyisocyanate

HDI/IPDI Polyisocyanateblend

L o w V i s c o s i t y

HDI Polyisocyanate

IsocyanurateTrimer

IsocyanurateTrimer

UretdioneUretdione Low MWTrimer

Low MWTrimerAllophanateAllophanate

ModifiedTrimersModifiedTrimers PrepolymersPrepolymers

IPDIIPDIHardness

Blends

Blends

AsymmetricTrimer

AsymmetricTrimer

IPDITrimer

IPDITrimerSuitable for blending in

2K WB coatings UV and weather resistanceWater, chemical, solvent resistanceCombination of hardness and flexibilityVariations in Structure and MW modify physical properties

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2K Waterborne Crosslinkers

Low Viscosity Low VOC

Higher Functionality

Low Viscosity, Low VOC

AllophanateAllophanate

ImprovedPerformance

RobustProcessing

ImprovedChemical

Resistance

ImprovedWeather

Resistance

Easy mixing

IsocyanurateTrimer

IsocyanurateTrimer

ureaureaAllophanateAllophanate UreaUrea

Chemicalresistance Easy mixing

Polyether modified

Lower MW Lower MW

Fast Drying (Tg)Chemical resistance

IsocyanurateTrimer

IsocyanurateTrimer

IPDI Polyisocyanate

HDI Polyisocyanate

Lower Viscosity Lower Viscosity

polyurethane chemistry and - wwdpi · polyurethane chemistry and products: ... 1960’s development...

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