additives polyurethane

of 32 /32
Additives Value beyond chemistry Enhanced Processing and Service Life for Polyurethane Products Additives for Polyurethane

Author: afteni

Post on 21-Nov-2014

568 views

Category:

Documents


8 download

Embed Size (px)

TRANSCRIPT

Additives for PolyurethaneEnhanced Processing and Service Life for Polyurethane Products

Additives

Value beyond chemistry

Table of ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Polymer Degradation and Stabilization . . . . . . . . . . . . . . . . . . . . . . . .4Thermo-oxidative Degradation . . . . . . . . . . . . . . . . . . . . . . .4 Antioxidants Interrupt the Degradation Process . . . . . . . . . . .5 Photodegradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Light Stabilizers Counter Photodegradation . . . . . . . . . . . . . .7

Additives for Polyurethane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9Thermoplastic Polyurethane (TPU) . . . . . . . . . . . . . . . . . . . .9 Reaction Injection Molded (RIM) Polyurethane . . . . . . . . . . .12 Polyurethane Foams . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Polyurethane Adhesives and Sealants . . . . . . . . . . . . . . . . .20 Polyurethane Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Additives Data Bank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Chemical Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 Chemical Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 FDA Clearance Summary . . . . . . . . . . . . . . . . . . . . . . . . . .28 Solubility Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

1

2

IntroductionPolyurethanes are among the most versatile polymers. They are used in a wide variety of applications including adhesives, sealants, coatings, fibers, reaction-injection molded components, thermoplastic parts, elastomers and both rigid and flexible foams. Polyurethanes offer an impressive range of performance characteristics and the use of appropriate stabilizers can extend the service life of polyurethane products. Selecting the best stabilization system depends on specific production conditions, end-use environment and a knowledge of the fundamental degradation mechanisms of the polyurethane components. Degradation of both the polyol and urethane components will cause changes in the physical or mechanical properties of the polyurethane. Urethanes are susceptible to degradation by free radical pathways induced by exposure to heat or ultraviolet light. The use of primary antioxidants, such as Irganox, suppresses the formation of free radical species and hydroperoxides in polyols both during storage and conversion. UV absorbers and hindered amine stabilizers, such as Tinuvin and ChimassorbTM, protect polyurethanes from UV light-induced oxidation. Ciba Additives offers a variety of additives for improving the processing and service life of polyurethane products. For detailed information about individual products, specific application or performance requirements, please contact your local Ciba technical representative or regional agent.

3

Polymer Degradation and StabilizationThermo-oxidative DegradationPolyurethanes, like other organic materials, react with molecular oxygen in a process call autoxidation. This degradation process results in product discoloration and loss of physical properties. Autoxidation may be initiated by heat, high energy radiation (UV light), mechanical stress, catalyst residues, or through reaction with other impurities. Free radicals (Figure 1) are generated which react rapidly with oxygen to form peroxy radicals. These peroxy radicals may further react with the polymer chains leading to the formation of hydroperoxides (ROOH). On exposure to heat or light, hydroperoxides decompose to yield more radicals that can reinitiate the degradation process.Figure 1. Polymer Degradation and StabilizationR RO ROO ROOH Alkyl radicals Alkoxy radicals Peroxy radicals Hydroperoxide

Path of degradation Path of stabilization

RH (Polymer)

Energy, Catalyst residues, Light

React with primary antioxidants (hindered phenols, hindered amine stabilizers) to yield inactive products (ROH and H2O)

Reacts with another RH

R

Carbon centered radicals react with Lactone based stabilizers Oxygen

Cycle II

Cycle IROOReacts with another RH Reacts with primary antioxidants (hindered phenols, hindered amine stabilizers)

RO + HOEnergy, Catalyst residues, Light

4

R + ROOHReacts with secondary antioxidants (phosphites, hydroxylamines) to yield inactive products

Microwave Scorch Test. Sample on right stabilized with Irganox antioxidants show much less exotherm discoloration than the other commercial system on the left. See complete test procedure on page 16.

Antioxidants Interrupt the Degradation ProcessAntioxidants interrupt the degradation process in different ways according to their structure. The major classifications of antioxidants are listed below. Primary Antioxidants, mainly acting in Cycle I of Figure 1 as chain-breaking antioxidants, are sterically hindered phenols. Primary antioxidants react rapidly with peroxy radicals (ROO) to break the cycle. Irganox1010, Irganox 1076, Irganox 1098, Irganox 1135 and Irganox 245 are examples of primary antioxidants. Secondary arylamines, another type of primary antioxidant, are more reactive toward oxygencentered radicals than are hindered phenols. Synergism between secondary arylamines and hindered phenols leads to regeneration of the amine from the reaction with the phenol. Irganox 5057 is an example of a secondary arylamine.

Secondary Antioxidants, acting in Cycle II of Figure 1, react with hydroperoxide (ROOH) to yield non-radical, non-reactive products and are, therefore, frequently called hydroperoxide decomposers. Secondary antioxidants are particularly effective in synergistic combination with primary antioxidants. Phosphite stabilizers, Irgafos 168 (a component of Irganox B Blends), Irgafos 12 (a component of Irganox LC Blends) and Irgafos 38 (a component of Irganox LM Blends) are secondary antioxidants. Multifunctional Antioxidants have special molecular design and optimally combine primary and secondary antioxidant functions in one compound. Hindered amine stabilizers (HAS) and dialkylhydroxylamine are prime examples of multifunctional antioxidants. Irganox 565 is another example of a multifunctional antioxidant. Hindered amine stabilizers can in some cases provide radical trapping effectiveness similar to hindered phenols. Traditionally used as light stabilizers, hindered amine stabilizers can also contribute to long-term thermal stability. Examples are Tinuvin 765, Tinuvin 123, Tinuvin 622 and Tinuvin 770. Dialkylhydroxylamines, a component of FS Systems, function as radical traps as well as hydroperoxide decomposers and reducing agents. Lactones, a component of our Irganox HP products, function as carbon-centered radical scavengers which inhibit autoxidation as soon as it starts and are further capable of regenerating phenolic antioxidants to provide new levels of overall processing stability.

5

Oxygen-Centered Radical TrapsOO

OOH

Ar2NH + -O-CH-CH2 Ar2N + ArOH

A

Ar2N + -O-CH-CH2

A Ar2NH + ArO

J. Pospisil in Developments in Polymer Stabilization, Vol. 1, Ch, 1, ed. G. Scott, Applied Science Publ., London, 1979.

Photodegradation

Photolysis O2

Autoxidation R'H

6

Photodegradation is really two distinct processes. The first is photolysis, a complex process occurring in several steps, which involves the absorption of UV radiation, followed by the formation of free radicals due to the breaking of the absorbing species molecular bonds. The second is autoxidation. Here, the free radicals formed during photolysis interact with oxygen to form peroxy radicals. There are five separate steps during photodegradation. In the following schematic, R represents the polymer or UV absorbing component.Step 1 RA R*

A

R AR* AR AROO AROOH ARO+OH Step 1 Step 2 Step 3 Step 4 + Step 5 R'

Step 3

O2 RA ROO

In Step 3, the free radicals formed during photolysis readily react with oxygen to form peroxy radicals. This is called autoxidation.Step 4

R'H ROOA ROOH + R'

Here, the polymer absorbs UV radiation. The energy from the absorbed UV radiation excites the absorbing species (either polymer molecules or impurities) and raises them to a higher energy level (R*). These excited state molecules are very reactive and may undergo a wide range of processes. Two common processes are returning to the ground state or homolytic bond cleavage.Step 2 R*A R

In Step 4, the peroxy radicals attack the polymer backbone (R'H) via hydrogen abstraction, forming hydroperoxides and more free radicals. These free radicals (R') again readily react with oxygen in Step 3 to form additional peroxy radicals.Step 5 ROOH A RO + OH

If the molecule cannot be brought to its ground state, homolytic bond cleavage and the formation of free radicals (R) will occur.

Finally in Step 5, the hydroperoxides, which are very unstable to both UV radiation and heat, fragment and form additional free radicals. As the processes continue, more and more molecular bonds break, leading to a deterioration of the desired properties.

Light Stabilizers Counter PhotodegradationPolyurethanes are subject to degradation when exposed to ultraviolet light from natural and/or artificial sources. Degradation results in discoloration and/or loss of physical properties. The main classes of light stabilizers are: Ultraviolet Light Absorbers (UVAs) Hindered Amine Light Stabilizers (HALS)During Step 1Figure 2. Schematic of Tautomerism

UV absorbers protect against photodegradation by competing with the polymer for absorption of ultraviolet light. As shown in Figure 2, the excitation energy of UV absorbers is rapidly and efficiently deactivated by the process of tautomerization. An ideal UVA should be very light stable, and should have high absorption over the UV range from 290 to 400 nanometers. Ciba Additives pioneered the development of benzotriazole ultraviolet light absorbers. Tinuvin P, Tinuvin 213, Tinuvin 326, Tinuvin 327, Tinuvin 328, and Tinuvin 571 belong to this class of UVAs.During Step 3

(A)N H O N N UV -

(B)+

N

H O N

N

7

Molecule A absorbs UV energy, resulting in an electronic rearrangement to form molecule B which, through the dissipation of heat energy, reverts to the original form, molecule A. This process is repeated indefinitely.

Figure 3. Regenerative Mechanism of HALS*R

Hindered amine light stabilizers (HALS) represent an alternative chemistry in light stabilization technology. Several theories have been advanced to explain the mechanism of stabilization by HALS, of which the most widely held involves efficient trapping of free radicals with subsequent regeneration of active stabilizer moieties, represented in Figure 3. Examples of HALS are Tinuvin 123, Tinuvin 144, Tinuvin 622, Tinuvin 765, Tinuvin 770, and Chimassorb 944.

[O] N-CH3

N-O

N-OR R'OO

R'OH + R=O N O O R' O R

* P.P. Klemchuk, M.E. Gande, Polymer Degradation and Stabilization, 1988, 22, 241; 1990, 27, 65

Additives for PolyurethanesCiba Additives for PolyurethanesAntioxidantsIrganox 245 Irganox 1010 Irganox 1076 Irganox 1098 Irganox 1135 Irganox 5057 Tinuvin P Tinuvin 213 Tinuvin 326 Tinuvin 327 Tinuvin 328 Tinuvin 571 Tinuvin 123 Tinuvin 144 Tinuvin 622 Tinuvin 765 Tinuvin 770 Uvitex OB

UVAs

HALS

8

Optical Brightener

Figure 4. UV Absorption Spectra (20 mg/l Ethyl Acetate)A 1.0

Figure 5. Weight Loss of Antioxidants TGA, 20C/min (air)Weight loss (%) 100 80 60

0.8

0.6 40 0.4 20 0.2 0 60 0.0 270 290 310 330 350 370 390 410 BHT Irganox 1135 Irganox 5057 Irganox 1076 Irganox 245 Irganox 1010 110 160 210 260 310 360 Temperature (C)

Wavelength (nm) Tinuvin 327 Tinuvin 328 Tinuvin 571 Tinuvin 213

ApplicationsThermoplastic Polyurethane (TPU)Thermoplastic polyurethanes are among the most versatile elastomeric materials. During the manufacture of TPUs, processing stabilizers such as Irganox 245, Irganox 1010 or Irganox 1098 are used to protect the polymer from degradation. Due to their versatility, TPUs are used in a wide range of applications that may require both thermal and/or light stability. For enhanced end-use stability, thermal stabilizers including Irganox 1135, Irganox 245 or Irganox 1010 are used. Light stability can be achieved using hindered amines alone (Tinuvin 765 or Tinuvin 123) or in conjunction with UV absorbers (Tinuvin 571 or Tinuvin 213). Also available is Tinuvin B75, a liquid blend of all three stabilizer functionalities - antioxidant (Irganox 1135) plus hindered amine (Tinuvin 765) plus UV absorber (Tinuvin 571). Tinuvin B 75 provides long term stability, ease of handling and outstanding end-use performance, all in one liquid product. To accommodate TPU processors, both liquid and solid stabilizers are available.

9

Table 1 shows the impact oxidation has on the initial color of polyurethane materials. Oxidation is measured by the peroxide concentration in the polyol. The resulting color development is measured by Yellowness Index of the final polyurethane.Table 1. Effect of Peroxide Concentration on Polyurethane* Initial Color Peroxide Conc. (ppm in the polyol) 1 25 50 100 PUR Yellowness Index 5 13 42 52

Figures 6 and 7 demonstrate the dramatic impact of stabilizers in thermoplastic polyurethanes. All formulations include Irganox 1135 antioxidant and Tinuvin 765 hindered amine stabilizer. After 500 hours Dry Xenon exposure, all three UV absorbers (Tinuvin 571, Tinuvin 328, and Tinuvin 327) show significant protection of color and retention of original elongation and tensile properties.Figure 6. Discoloration of TPU Plaques (1.5 mm)Exposure: Base Stabilization:Control

500 Hours Light Exposure. Dry Xenon CI 35: b.P. TC = 63C, 0.35W/m2 Irradiance 0.25% Irganox 1135/0.25% Tinuvin 765

0.5% Tinuvin 571

* Shoe sole formulation, non-pigmented, PUR is polyether based.

10Antioxidants are needed to protect TPU during processing. Both Irganox 1010 and Irganox 245 have been used in commercial production successfully for many years. The stabilized TPU samples were able to sustain two times longer ovenaging exposure than the sample without an antioxidant (Table 2).Table 2. Ovenaging of Thermoplastic Polyurethane Sample: 2 mm injection molded dumb-bells Test Criterion: Ovenaging time at 120C till discoloration increases 20 YellownessIndex units. Days to YI=20 At 120C Unstabilized 0.3% Irganox 1010 0.3% Irganox 245 3 6.5 6.5

0.5% Tinuvin 328

0.5% Tinuvin 327

0

10

20

30

40 E

Figure 7. Tensile Strength and Elongation Retention of TPU Plaques (1.5 mm)Exposure: Base Stabilization: 500 Hours Light Exposure. Dry Xenon CI 35: b.P. TC = 63C, 0.35W/m2 Irradiance 0.25% Irganox 1135/0.25% Tinuvin 765

Tensile Strength

Elongation

0

20

40

60

80

100 120 % Retention

Control 0.5% Tinuvin 571 0.5% Tinuvin 328 0.5% Tinuvin 327

Substantial improvement in performance can be achieved using a UVA/HALS combination vs UVA alone, as demonstrated in Figure 8.Figure 8.Sample: Exposure:Unstabilized 0.3% Tinuvin 328 0.3% Tinuvin 213 0.4% Tinuvin 328 + 0.4% Tinuvin 765 0.4% Tinuvin 213 + 0.4% Tinuvin 765 0 100 200 300 132 269

Accelerated Weathering, TPU FilmTPU Film, 6 mm Xenotest 45037 174

443 400 500 Hours to delta YI of 20

Table 3 compares the light stability of aromatic vs. aliphatic based polyurethanes. Although stabilizers do provide some improvement in light stability for aromatic polyurethane, light stabilizers are particularly effective in aliphatic polyurethane.Table 3. Comparison of Light Stability of Aromatic and Aliphatic Polyurethane Film Xenon Weather-Ometer Exposure Hours to 50% Retention of Elongation Aromatic Control 0.5% Tinuvin P + 0.5% Irganox 1010 0.5% Chimassorb 944 0.5% Tinuvin 622 0.5% Tinuvin 765 170 390 900 670 850 Aliphatic 3,200 4,500 11,500 11,500 13,900

During storage and end use, TPUs can be exposed to nitrogen oxides that may cause the polymer to discolor. This discoloration can be minimized using a hindered amine (Tinuvin 765 or Tinuvin 770) or a combination of stabilizers as shown in Table 4.Table 4. Effect of Nitrogen Oxides* on Polyester-Based Polyurethane Yellowness Index After 334 Hours Unstabilized 1% Tinuvin P 1% BHT 1% Tinuvin 770 1% Tinuvin P + Tinuvin 770 (1:1) 1% Tinuvin 770 + Irgafos 168 (1:1) 1% Tinuvin 765 53 50 34 15 13 10 9

11

* PUR plaques were maintained in an enclosed chamber with nitrogen oxides present for 334 hours at 60C. PUR is a non-pigmented shoe sole type formulation.

Reaction Injection Molded (RIM) PolyurethanePolyurethane parts can be made by the RIM (reaction injection molding) process. Raw materials are injected into a mold where the polymerization occurs. Depending on the end use of the product, enhanced light or long-term thermal stability may be required. In particular, automotive parts have stringent performance requirements for which a combination of UV absorbers (Tinuvin 571, Tinuvin 213, Tinuvin 328), hindered amine stabilizers (Tinuvin 765, Tinuvin 123, Tinuvin 770), and/or antioxidants (Irganox 1135, Irganox 1010, Irganox 245) are used. Figure 9 shows the strong performance of UV absorbers with hindered amine stabilizers and antioxidants in a black PUR RIM exposed in the Weather-Ometer.

12

Figure 9.

Light Stability of Black RIM Polyurethane Plaques (2 mm)

Test Criterion: Discoloration after WOM CI 65: b.P. TC = 63, r.H. = 60%E 15 12 9 6 3 0

0

250

500

750

1000 Time (Hours)

Control 1.5% Tinuvin B 75 1% Irganox 1010 +1% Tinuvin 770 +1% Tinuvin P

Figure 10 shows the reduction in yellowness when light stabilizers are used. Tinuvin B 75, a liquid blend of three stabilizer functionalities, provides good control of color development in a white integral skin polyurethane foam sample even after hundreds of hours of dry light exposure. Figure 11 is the sample exposed in a wet cycle. Despite the more severe conditions, Tinuvin B 75 provides excellent light stability.

Figure 10. PUR White Integral Foams DiscolorationExposure: Xenotest 450, Dry Cycle BP = 45C; Relative Humidity = 65%

Yellowness Index 70 60 50 40 30 20 10

0

50

100

150

200

250

300

Exposure Time (hours) Unstabilized (Total conc. 0%) Irganox 245 + Tinuvin 328 + Tinuvin 765 (1% conc. 1:2:2 ratio) Irganox 245 + Tinuvin 571 + Tinuvin 765 (1% conc. 1:2:2 ratio) Irganox 1135 + Tinuvin 571 + Tinuvin 765 (1% conc. 1:2:2 ratio is Tinuvin B 75)

13Figure 11. PUR White Integral Foams DiscolorationExposure: Weather-Ometer, Wet Cycle BP = 45C; Wet Cycle 112/18

Yellowness Index 70 60 50 40 30 20 10

0

20

40

60

80

Exposure Time (hours) Unstabilized (Total conc. 0%) Irganox 245 + Tinuvin 328 + Tinuvin 765 (1% conc. 1:2:2 ratio) Irganox 245 + Tinuvin 571 + Tinuvin 765 (1% conc. 1:2:2 ratio) Irganox 1135 + Tinuvin 571 + Tinuvin 765 (1% conc. 1:2:2 ratio is Tinuvin B 75)

14

Polyurethane FoamsPolyurethane can be foamed and shaped into flexible, rigid and integral skin configurations. Each of these types of applications will have specific stabilizer requirements. When producing flexible slabstock foams, the exotherm from the polyol/isocyanate reaction can cause discoloration, called scorch, in the center of the foam. This phenomenon is most common in flexible slabstocks because of the size of the foam. Since polyurethane foam is a good insulator, the interior of the foam stays hot for many hours, increasing the risk of scorching. Because of their limited size, rigid and integral skin foams tend not to be as prone to scorching as flexible slabstock foams. Hindered phenolic antioxidants (Irganox 1076, Irganox 1135) with alkylated diphenyl amines (Irganox 5057) in the polyol provide good protection against scorch. Selection of the additive package will be determined by a number of factors including foaming technique and end-use characteristics. Many processors prefer Irganox 1076 and Irganox 1135 due to their lower volatility relative to BHT. Antioxidants are used to protect the urethane from processing and end-use degradation and protect polyol from oxidation during storage and transport. Many end-use applications for rigid and integral skin foams are subject to outdoor exposure requiring light stabilizers to provide ultraviolet protection.

Polyurethane Foam Test MethodsPolyol and Flexible Polyurethane Foam Stabilization Test Methods Polyetherpolyol Analytical Determination of Isocyanate Polyurethane Flexible Foams/Textile Staining Test Swiss Federal Laboratories for Materials Testing and Research (EMPA) St. Gallen, Switzerland Sample preparation Two foam samples of each formulation are exposed for 3 hours to air containing 50 ppm and 5 ppm NOx gas respectively. The samples are then covered with two layers of cotton textile (MOLTON), which has been previously washed with a softener, and wrapped with aluminium film. Samples aging Foaming Formulation Scorch Test 1) The samples are put into an air-circulating oven at 40C. 2) Another series of samples, covered with one layer of textile, is exposed for one month in air. These samples, under exclusion of direct sun radiation, are not wrapped in aluminium film and not gassed. Measurement of the textile discoloration 1) Samples gassed with 50 ppm NOx gas. The first textile layer is evaluated after 24 hours. The second textile layer is evaluated after 48 hours. 2) Samples gassed with 5 ppm NOx gas. The first textile layer is evaluated after 48 hours. The second textile layer is evaluated after 96 hours. 3) Samples exposed in air. The textile layer is evaluated after 1 month. The textile discoloration is measured by comparing the color difference between the exposed and the unexposed textile sample.

Antioxidant content Peroxide formation(long-term storage) Differential Scanning Colorimetry DSC Exotherm peak of oxidation reactions (effectiveness of antioxidants)

Microwave/Humidity exposure Static ALU-Block Test Dynamic ALU-Block Test

15

(discoloration, YI) Differential Scanning Colorimetry (DSC)

Exotherm peak of oxidation reactions(effectiveness of antioxidants) Gasfading Test with NOx

Yellowing of foam Yellowing of textilesa. Volatility of antioxidants b. Reactivity with NOx c. Identification of reaction products

Microwave Scorch Test Procedure1. A master batch is prepared containing surfactant,

water and amine catalyst. 2. An appropriate amount of the master batch is added to 150 g polyol, along with the antioxidant package. 3. The mixture is stirred for 10 seconds at 2600 rpm. The tin catalyst is added and the mixture is stirred for 18 seconds at 2600 rpm. The TDI is then added and the mixture stirred for an additional 5 seconds at 2600 rpm. 4. The mixture is poured into an 8x8x4 cake box. Cream times are typically 9-12 seconds, and rise times 87-94 seconds. 5. After 2 minutes 14 seconds, a 4x4 piece of the top skin is removed. This piece is removed with a 4x4 piece of cardboard supported by a pencil to a 3M double-sided Scotch Brand Tape. 6. After 5 minutes, the sample is placed inside a microwave oven with 1 cup water in a separate container, then microwaved at 50% power for 5 minutes 15 seconds. This microwave time is chosen so that a delta E value of about 20 is obtained for a standard formulation (e.g. 0.40% Irganox 1135 + 0.10% Irganox 5057).

16

Processing Stabilization of Polyurethane FoamsFor polyol producers and foamers seeking lower volatility alternatives to BHT for scorch protection, both Irganox 1135 and Irganox 1076 are excellent choices. Irganox 1135 in combination with Irganox 5057 is the ideal liquid stabilizer system for polyurethane flexible forms. Irganox 1135 has lower volatility than BHT (see TGA data on page 8) and the liquid nature of Irganox 1135 and Irganox 5057 provides ease of incorporation for liquid based processing. Figure 12 demonstrates the outstanding scorch protection provided by a 2:1 ratio of Irganox 1135 and Irganox 5057. A 4:1 ratio of Irganox 1076 and Irganox 5057 also provides equal performance to the BHT system in the microwave scorch test. In ovenaging tests carried out in an aluminumblock oven, the foam sample stabilized with 3000 ppm of a combination of Irganox 1135 and Irganox 5057 at 2:1 ratio showed the longest time to reach a Yellowness Index of 25 (Figure 13). For polyester foam samples, ovenaging tests in an aluminum-block oven show improvement in stability, whether testing Irganox 1135 alone or in combination with Irganox 5057 (Figure 14).Figure 13. Polyether Flexible Foams StabilizationExposure:Unstabilized BHT

Dynamic Heat Test, Ovenaging for 30 MinutesUnstabilized = 89C

17Irganox 1135 BHT + Irganox 5057 (ratio 2:1) Irganox 1135 + Irganox 5057 (ratio 2:1) 160 170 180 190 200

Temperature (C) to reach Yellowness Index = 25 Total additive concentration = 3000 ppm

Figure 12. Microwave Scorch Testing of Polyether Polyurethane Cake Box FormsFoam Formulation: 150.00 g Polyether Polyol, 1.50 g Surfactant, 6.75 g Water, 0.375 g Amine Catalyst, 0.12 g Tin Catalyst, 92.40 g Toluene Diisocyanate17 18 29 24 17 20 17 32 44 0 10 20 30 40 50 E

Figure 14. Polyester Flexible Foams StabilizationExposure: Dynamic Heat Test, Ovenaging for 30 Minutes

0.5% BHT/ Irganox 5057

Unstabilized

Irganox 1135

0.5% Irganox 1135/ Irganox 5057

0.5% Irganox 1076/ Irganox 5057

Irganox 1135 + Irganox 5057 (ratio 1:1)

190

195

200

205

210

Temperature (C) to reach Yellowness Index = 25 Total additive concentration = 3500 ppm

4:1 Ratio 2:1 Ratio 1:1 Ratio

Stabilization Minimizes Textile StainingIn many applications such as automotive interiors, furniture, mattresses, carpeting and shoulder pads polyurethane flexible foams come in contact with textiles. Proper stabilizers are needed to prevent scorching of the foam and subsequent staining of the textile. Figures 15, 16, and 17 show how the proper selection of scorch inhibitors can minimize gas fade discoloration in textiles. Irganox 1135 or Irganox 1076 limits the discoloration associated with NOx exposure vs. BHT. Figure 15 is an air exposed sample. Whereas, the sample in Figure 16 was exposed to 5 ppm NOx for 48 and 96 hours. Figure 17 shows a more severe exposure of 50 ppm NOx.

Figure 15. Gasfade Discoloration of PUR Flexible FoamControl(BHT-free polyether polyol)

3

Exposure:

MOLTON Textile 1 Month Storage in Air (EMPA-Test)20.7 3

0.24 % BHT + 0.06% Irganox 5057 Control (BHT-free polyether polyol) 0.24 % Irganox 1135 + 0.06% Irganox 5057 0.24 % BHT 0.24 % Irganox 5057 + 0.06%Irganox 1076 + 0.06% Irganox 5057 0.24 % Irganox 1135 + 0.06% Irganox 5057 0.24 % Irganox 1076 + 0.06% Irganox 5057 0 0

1.1

0.7 1.1

20.7

5

10

15

20

25 E

0.7

5

10

15

20

25 E

18

Figure 16. Gasfade Discoloration of PUR Flexible FoamExposure: MOLTON Textile Ovenaging at 40C (EMPA-Test)

Figure 17. Gasfade Discoloration of PUR Flexible FoamExposure: MOLTON Textile Ovenaging at 40C (EMPA-Test)0.7 1.1 8.8 4.4 0.8 0.7 0.7 1 0 50 ppm NOx 24 hours 48 hours 2 4 6 8 10 E

Control(BHT-free polyether polyol)

Control 1.2 1.2 2 2.6 0.9 0.9 1.4 1.2 0 1 2 3 4 EBHT-free polyether polyol

0.24 % BHT + 0.06% Irganox 5057 0.24 % Irganox 1135 + 0.06% Irganox 5057 0.24 % Irganox 1076 + 0.06% Irganox 5057

0.24 % BHT + 0.06% Irganox 5057 0.24 % Irganox 1135 + 0.06% Irganox 5057 0.24 % Irganox 1076 + 0.06% Irganox 5057

5 ppm NOx 48 hours 96 hours

Light Stabilization of Polyurethane FoamsThe micrographs in Figure 18 show that a combination of a hindered amine (Tinuvin 765) and ultraviolet absorber (Tinuvin 328) can help protect the cell structure of a polyether polyurethane foam during exposure to light. Note that the cell structure of the stabilized foam looks similar to the unexposed foam even after l50 hours of Xenon exposure.

Figure 18. Surface microcrazing of Foamed Polyether Urethane Unexposed Magnification: 1,000X

19

Exposure: 150 hours in Xenon Weather-Ometer Magnification: 1,000X Unstabilized

Exposure: 150 hours in Xenon Weather-Ometer Magnification: 1,000X Stabilization System: 0.5% Tinuvin 328 + 0.5% Tinuvin 765

Polyurethane Adhesives and SealantsPolyurethanes are widely used for formulating adhesives and sealants. Polyurethane adhesive formulations include both solvent-based as well as hot-melt. In some cases, high-performance adhesives can replace standard mechanical bonding methods such as nuts and bolts, screws and welding. Appropriate stabilizers are important in retarding degradation and maintaining physical properties for production of high quality adhesives. Antioxidants, such as Irganox 1010 or Irganox 245 provide good processing stability, and Tinuvin B 75, Tinuvin 571, Tinuvin 765 or Tinuvin 123 can provide enhanced light stability. Figure 19 shows that light stabilizers in combination with antioxidants (Tinuvin B 75 or a combination of Irganox 245 and Tinuvin 571) provide the best overall protection in this solvent-based polyurethane adhesive.

Figure 19. Stabilization of Solvent-Based Polyurethane AdhesivesSample: 100p PUR, 30% MEK, 50p toluene, 10p hardner Test Criterion: Yellowness Index after exposure in Xenon 150Yellowness Index 25 20 15 10 5 0

0

1

2

3

4

5 Days

Unstabilized 0.75% Irganox 245 + Tinuvin 571, 1:2 0.75% Irganox 245 + Tinuvin 765, 1:2 0.75% Tinuvin B 75 0.50% Tinuvin 571 0.50% Tinuvin 765

20

In a 2-part polyurethane sealant, all stabilization formulations show significant improvement over the unstabilized control. After 2000 hours of Carbon Arc exposure, the ternary blend of Irganox 245 + Tinuvin 328 + Tinuvin 765 shows the best performance (Figure 20).Figure 20. 2-Part Polyurethane Sealant with Amine CurativeTest Criterion: Degree of crazing after Carbon Arc Weather-Ometer exposureDegree of Crazing 5 4 3 2 1 0

Figure 21 shows the effects of various light stabilizer/antioxidant combinations for stabilizing a polyurethane sealant formulation. A 1:2:2 ratio of Irganox 245:Tinuvin 213:Tinuvin765 results in the lowest color development after Xenon exposure.Figure 21. Light Stabilization of Polyurethane SealantDelta E: ASTM D1925, D65 Illuminant, 10 observer, LAV Test Criterion: Color Development (Delta E) after Dry Xenon Arc Weather-Ometer Exposure

Unstabilized

15 15

1.25% Irganox 245 + Tinuvin 328 + Tinuvin 765, 1:2:2

11 12

1.25% Irganox 245 + Tinuvin 213 + Tinuvin 765, 1:2:2

9 10

210 500 1000 1500 2000 5 10 15 Hours, Carbon Arc Weather-Ometer Unstabilized 0.50% Tinuvin 0.75% Tinuvin 0.75% Tinuvin 1.50% Tinuvin 765 765 765 765 + + + + Irganox 245, 1:1 Irganox 245, 2:1 Tinuvin 328 + Irganox 245, 1:1:1 Tinuvin 328 + Irganox 245, 1:1:1 100 hours XAW exposure 250 hours XAW exposure 20 E

Degree of Surface Crazing: 0 = no crazing 3 = moderate crazing 1 = very slight crazing 4 = significant crazing 2 = slight crazing 5 = severe crazing

Polyurethane FiberPolyurethane fiber commonly known as spandex is a synthetic elastomeric fiber. It is strong with very high extensibility and recoverability characteristics (elasticity) making it ideal for such textile applications as swimsuits, hosiery and fitness garments. Production of polyurethane fiber typically requires antioxidants, such as Irganox 245 or Irganox MD1024. For enhanced performance demanded by consumers, light stability for exterior exposure is provided by combinations of ultraviolet light absorbers (Tinuvin 328, Tinuvin 234 or Tinuvin 327) with hindered amines (Tinuvin 765, Chimassorb 944 or Tinuvin 622). Figure 22 shows a polyurethane fiber sample in which Tinuvin 213 and Tinuvin 234 used in combination with Tinuvin 765 showed no signs of failure even after 800 hours of dry Xenon exposure. In the same test, the unstabilized sample failed shortly after 200 hours, while the sample with Tinuvin 328 in combination with Tinuvin 765 failed after 496 hours. This failure is probably because of the loss of Tinuvin 328 due to its volatility. However, the same stabilizer combination of Tinuvin 328 and Tinuvin 765 showed good gas fade resistance (Figure 23). Light stability of polyurethane fibers is key for many outdoor applications. The Xenotest data in Figure 24 shows that a processing stabilizer with a hindered amine light stabilizer (Tinuvin 622) does provide some protection, but with the addition of a UV absorber (Tinuvin 234), the time to a YI of 20 was increased by a factor of three.

22

Figure 22

Light Stabilization of Polyurethane Fiber

Test Criterion: Color Development (YI) after Dry Xenon Exposure

Yellowness Index 25 21.7* 20

15

10 5.4* 5 6 6.9

0

200

400

600

800 Hours

Unstabilized 1.0% Tinuvin 328 + Tinuvin 765, 1:1 1.0% Tinuvin 213 + Tinuvin 765, 1:1 1.0% Tinuvin 234 + Tinuvin 765, 1:1 * Physical Property Failure

23

Figure 23. Gas Fading of Polyurethane FiberExposure: NOx Chamber Test Criterion: Color Development (YI) after NOx ExposureUnstabilized 1.4 18.6

Figure 24. Stabilization of Polyurethane FiberTest Criterion: Time to reach YI = 20 after Xenotest 1200

Control

80

0.5% Cyanox* 1790 1.0% Tinuvin 328 + Tinuvin 765, 1:1 0 0.3 6.1 5 10 15 20 Yellowness Index 0.5% Cyanox 1790 + 0.5% Tinuvin 622 0.5% Cyanox 1790 + 0.5% Tinuvin 622 + 0.5% Tinuvin 234 0

78

100

300

0 hours 50 hours

100

200

300 Hours

* Cyanox is a registered trademark of Cytec Corporation

Data BankChemical Structures of Ciba Additives for Polyurethane

Irganox 245OH

Irganox 1010OH

Irganox 1076OH

O CH2 CH2CO(CH2CH2O)3 2

O

O O 4 C

CH2CH2 COC18H37

Irganox 505724R N HR, R1 = H, C4H9, or C8H17 and other alkyl chains.

Tinuvin 123R1H17C8O N O OC (CH2)8 O CO N OC8H17

Tinuvin PHO N N N CH3

Tinuvin 326HO N N CI N CH3

Tinuvin 327HO N N CI N

Tinuvin 622H3C H O H H3C CH3 N CH2 CH2 O O C CH2 CH2 O C O CH3

Tinuvin 765O CH3 N O C (CH2)8 O C O N CH3

CH3 n

Irganox 1098O HO CH2CH2CNH(CH2)3 2

Irganox 1135O HO CH 2 CH 2 C O R

R = C 7-9 Branched Alkyl Esters

Tinuvin 144O H3C N O C C H3C N O C O C4H9 CH2 OH

Tinuvin 213OH N N N in 13% Polyethyelene glycol O CH2CH2C O(CH2CH2O)N

25

Tinuvin 328HO N N N C(CH3)2CH2CH3 C(CH3)2CH2CH3

Tinuvin 571OH N N N CH3 C12H25

Tinuvin 770O HN O C (CH2)8 O C O NH

Uvitex OBN S N

O

O

Chemical Names of Ciba Additives for PolyurethanesAdditive Irganox 245 Irganox 1010 Irganox 1076 Irganox 1098 Irganox 1135 Irganox 5057 Tinuvin P Tinuvin 123 Tinuvin 144 Tinuvin 213 Chemical Name Ethylene bis (oxyethylene) bis(3-tert-butyl-4-hydroxy5(methylhydrocinnamate) Tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy hydrocinnamate)]methane Octadecyl 3,5-di-tert-butyl-4-hydroxyhyrocinnamate N,N-Hexamethylene-bis (3,5-di-tert-butyl-4-hydroxyhyrocinnamamide) 3,5-Di-tert-butyl-4-hydroxyhydrocinnamic acid,C7-9 branched alkyl esters N-phenylbenzen amine, reaction products with 2,4, 4-trimethylpentene 2-(2-Hydroxy-5-methylphenyl)-benzotriazole bis-(1-Octyloxy-2,2,6,6,tetramethyl-4- piperidinyl) sebacate (trivial name) n-Butyl-(3,5-di-tert-butyl-4-hydroxybenzyl)bis-(1,2,2,6pentamethyl-4piperridinyl)malonate Poly (oxy-1,2-ethanediyl), (_,(3-(3-(2H-benzotriazol-2-yl)-5(1,1-dimethylethyl)-4-hydroxyphenyl)-1-oxopropyl)-t-hydroxy; Poly (oxy-1,2-ethanediyl), (_-(3-(3-(2H-benzotriazol-2-yl)-5(1,1-dimethylethyl)-4-hydroxyphenyl)-1-oxopropyl-t(3-(3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl) -4-hydroxyphenyl)-1-oxopropoxy) Tinuvin 326 Tinuvin 327 Tinuvin 328 Tinuvin 571 2-(5-Chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4methylphenol 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole 2-(2H-Benzotriazol-2-yl)-4,6-bis(1,1-dimethylpropyl)phenol 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, branched and linear Dimethyl succinate polymer with 4-hydroxy-2,2,6,6-tetramethyl1-piperidineethanol bis(1,2,2,6,6,-Pentamethyl-4-piperidinyl) sebacate (major component) bis(2,2,6,6-Tetramethyl-4-piperidinyl) sebacate 2,2-(2,5-thiophenediyl)bis[5-tert-butylbenzoxazole] CAS No. 36443-68-2 6683-19-8 2082-79-3 23128-74-7 125643-61-0 68411-46-1 2440-22-4 129757-67-1 6384-3-89-0 104810-48-2 104810-47-1

26

3896-11-5 3864-99-1 25973-55-1 125304-04-3

Tinuvin 622 Tinuvin 765 Tinuvin 770 Uvitex OB

65447-77-0 41556-26-7 52829-07-0 7128-64-5

Physical Properties of Ciba Additives for PolyurethanesAdditive Molecular Weight Melting Point (C) Specific Gravity at 20C 1.14 1.15 1.02 1.04 0.95-1.0 0.98 1.38 TGA, in air at 20C/min. Temp. at 1% Wt. Loss 290 310 230 290 160 130 180 Temp at 10% Wt. Loss 330 355 290 330 200 200 205 white powder white powder white powder white crystalline powder clear to slight yellow liquid pale yellow liquid light yellow crystalline powder pale yellow liquid off-white powder yellow to light amber liquid light yellow powder pale yellow powder off-white powder pale yellow liquid off-white powder clear to slight yellow liquid white powder yellow powder Appearance*

Irganox 245 Irganox 1010 Irganox 1076 Irganox 1098 Irganox 1135 Irganox 5057 Tinuvin P

587 1178 531 640 391 330 225

76-79 110-125 50-55 156-161 liquid 0 - 5 (liquid) 128

Tinuvin 123 Tinuvin 144 Tinuvin 213 Tinuvin 326 Tinuvin 327 Tinuvin 328 Tinuvin 571 Tinuvin 622 Tinuvin 765 Tinuvin 770 Uvitex OB

737.2 685 637 (comp.1) 975 (comp. 2) 316 358 352 394 >2500 509 481 431

liquid 146-150 liquid 138-141 154-158 79-87 liquid 55-70 liquid 82-86 196-202

0.97 1.07 1.17 1.32 1.26 1.17 1.0 1.18 0.99 1.05 1.26

160 250 140 200 180 190 170 290 225 200 300

265 290 280 245 235 230 245 320 275 260 340

27

* Many products are available in product forms other than powders 10C/min in nitrogen 20C/min in nitrogen 10C/min in air

FDA Clearance Summary (1)Product Irganox 245 Irganox 1010 Existing Regulations Adhesives complying with 175.105 All polymers used as indirect additives in food packaging Adhesives complying with 175.105 Pressure sensitive adhesives complying with 175.125 Irganox 1076 Adhesives complying with 175.105 Rubber articles complying with 177.2600 Irganox 5057 Rubber articles complying with 177.2600 Pressure sensitive adhesives complying with 175.125 Tinuvin 328 Uvitex OB Adhesives complying with 175.105 Adhesives complying with 175.105 Max. Conc. no restrictions 0.5% no restrictions 1% no restrictions 5% Thickness no restrictions no restrictions no restrictions no restrictions no restrictions no restrictions Foods Allowed no restrictions no restrictions no restrictions no restrictions no restrictions no restrictions no restrictions Temperatures Allowed no restrictions no restrictions no restrictions no restrictions no restrictions no restrictions no restrictions

5% no restrictions (total antioxidant level) 0.5% no restrictions no restrictions no restrictions no restrictions no restrictions

no restrictions no restrictions no restrictions

no restrictions no restrictions no restrictions

(1) The products listed herein have been cleared by the Food and Drug Administration for use in polymers intended for

28

food contact applications, in accordance with the cited regulations as printed in Title 21, U.S. Code of Federal Regulation (21 CFR), or as amended by the Federal Register, which should be consulted before use.

Solubilities of Ciba Additives for PolyurethanesAdditive Water Irganox 245 Irganox 1010 Irganox 1076 Irganox 1098 Irganox 1135 Irganox 5057 Tinuvin P Tinuvin 123 Tinuvin 144 Tinuvin 213 Tinuvin 326 Tinuvin 327 Tinuvin 328 Tinuvin 571 Tinuvin 622 Tinuvin 765 Tinuvin 770 Uvitex OB