ANTIOXIDANT COMPOSITIONS

Abstract

The invention provides a stabilising composition for polymeric materials, comprising: a. a first derivatised phenolic antioxidant; b. at least one secondary arylamine having the formula (I): NHRyRx wherein: the or each R, which may be the same or different, independently denotes an optionally substituted hydrocarbyl group; x and y are each independently from 0 to 5 provided that at least one of x and y is at least 1; and provided that at least one R is an optionally substituted hydrocarbyl group having at least 9 carbon atoms; and c. one or more antioxidant boosters independently selected from: i. a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant; ii. a hindered amine; iii. an optionally substituted phenothiazine; and also the use of the stabilising composition for stabilising polyol and/or polyurethane; and a stabilised composition comprising a polyol and/or polyurethane and the aforementioned low emission and anti-scorch stabilising composition.

##STR00001##

Claims

1. A stabilising composition for polymeric materials, comprising: a. a first derivatised phenolic antioxidant; b. at least one secondary arylamine having the formula I: ##STR00008## wherein: each R, which may be the same or different, independently denotes an optionally substituted hydrocarbyl group; x and y are each independently from 0 to 5 provided that at least one of x and y is at least 1; and provided that at least one R is an optionally substituted hydrocarbyl group having at least 9 carbon atoms; and c. one or more antioxidant boosters independently selected from the group consisting of: i. a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant; ii. a hindered amine; and iii. an optionally substituted phenothiazine.

2. The stabilising composition according to claim 1, wherein at least one of R.sub.x and R.sub.y is an optionally substituted hydrocarbyl group having 9 carbon atoms.

3. The stabilising composition according to claim 2, wherein at least one of R.sub.x and R.sub.y is a nonyl group.

4. The stabilising composition according to claim 1, wherein x and y are each independently from 0 to 2 provided that at least one of x and y is at least 1.

5. The stabilising composition according to claim 1, wherein the stabilising composition is substantially free from diphenylamine and from lower alkylated diphenylamine antioxidants.

6. The stabilising composition according to claim 1, wherein the stabilising composition is substantially free from t-butylated diphenylamines.

7. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant has a molecular weight of at least about 390.

8. The stabilising composition according to claim 1, wherein the second derivatised phenolic antioxidant has a molecular weight lower than about 600.

9. The stabilising composition according to claim 1, wherein the booster comprises a second derivatised phenolic antioxidant wherein: a. the number of substituent groups ortho to the or a phenolic moiety in the second derivatised phenolic antioxidant is lower than the number of substituent groups ortho to the or a phenolic moiety in the first derivatised phenolic moiety: and/or b. the size of any substituent group ortho to the or a phenolic moiety in the second derivatised phenolic antioxidant is smaller than the size of any substituent group ortho to the or a phenolic moiety in the first derivatised phenolic moiety.

10. The stabilising composition according to claim 1, wherein the booster comprises one or more second derivatised phenolic antioxidants selected from the group consisting of an optionally substituted mono-hydroxybenzene, a di-hydroxybenzene, and a tri-hydroxybenzene.

11. The stabilising composition according to claim 1, wherein the booster comprises a hindered amine light stabilizer.

12. The stabilising composition according to claim 1, wherein the booster comprises an optionally substituted phenothiazine.

13. The stabilising composition according to claim 1, wherein the composition is a liquid at 25° C. and atmospheric pressure.

14. The stabilising composition according to claim 1, wherein the stabilising composition is substantially free from secondary or tertiary arylamines having vapour pressures above 0.03 Pa at 20° C.

15. The stabilising composition according to claim 14, wherein the individual secondary or tertiary arylamines components are each present in an amount of less than 2.0% w/w of the stabilising composition.

16. The stabilising composition according to claim 15, wherein the total amount of secondary or tertiary arylamines components are present in an amount of less than 2.0% w/w of the stabilising composition.

17. The stabilising composition according to claim 1, wherein the contribution to VOC of the stabilising composition is less than 20 ppm.

18. The stabilising composition according to claim 1, wherein the contribution to FOG of the stabilising composition is less than 200 ppm.

19. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant comprises a phenol group which is substituted.

20. The stabilising composition according to claim 19, wherein the or each substituent comprises an alkyl group.

21. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant is present in an amount of from 20 to 60% w/w.

22. The stabilising composition according to claim 1, wherein the at least one secondary arylamine is present in an amount of from 35 to 75% w/w.

23. The stabilising composition according to claim 1, wherein the antioxidant booster is present in an amount of from 0.25 to 20% w/w.

24. A stabilising composition for polymeric materials, comprising: a. a first derivatised phenolic antioxidant; b. at least one secondary arylamine having the formula III: ##STR00009## wherein: each R, which may be the same or different, independently denotes an optionally substituted hydrocarbyl group; x and y are each independently from 0 to 5 provided that at least one of x and y is at least 1; and provided that at least one R is an optionally substituted hydrocarbyl group having at least 5 carbon atoms and present in an amount of from 35 to 75% w/w of the stabilising composition; and c. one or more antioxidant boosters independently selected from the group consisting of: i. a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant; ii. a hindered amine; and iii. an optionally substituted phenothiazine.

25. A stabilised composition comprising a polyol and a stabilising composition according to claim 1.

26. A stabilised composition comprising a polyurethane and a stabilising composition according to claim 1.

27. The stabilised composition according to claim 25, wherein the stabilising composition is present in the stabilised composition in an amount of from about 0.01 to about 2% by weight of the polymeric material.

28-32. (canceled)

33. The stabilised composition according to claim 26, wherein the stabilising composition is present in the stabilised composition in an amount of from about 0.01 to about 2% by weight of the polymeric material.

Description

EXAMPLES

[0130] The individual components of the stabilising compositions investigated herein are outline in Table 1 below. Hereinafter, the stabilising components will simply be referred to using the name given in the ‘component’ column.

TABLE-US-00001 TABLE 1 Component CAS No. Description AO 945 6683-19-8 a prior art blend of 25% ANOX ™ 20 (a derivatised 68411-46-1 phenolic), 65% NAUGARD ™ PS30 (a mixture of 92-84-2 derivatised arylamines and a reaction product of 64742-52-5 diphenylamine, diisobutylene and isobutylene), 1% phenothiazine and 9% process oil A1315 171090-93-0 ANOX ™ 1315 - C13-C15 linear and branched alkyl esters of 3-(3′-5′-di-t-butyl-4′-hydroxylphenyl) propionic acid with ANOX ™ PP-BASE (CAS 6386- 38-5) content of <2000 ppm A20 6683-19-8 ANOX ™ 20 - Tetrakismethylene(3,5-di-t-butyl-4- hydroxyhydrocinnamate) methane A70 41484-35-9 ANOX ™ 70 - 2,2′ Thiodiethylenebis[3-(3,5-di-t- butyl-4-hydroxyphenyl)propionate] PS30 68411-46-1 NAUGARD ™ PS30 - Diphenylamine C4/C8 reaction product PTZ 92-84-2 Phenothiazine Nonyl.DPA 36878-20-3 NAUGALUBE ™ 438L - A mixture of mono-nonyl and di-nonyl diphenylamines with a DPA (diphenylamine) content <1000 ppm and a colour < Gardner 5 Process oil 64742-52-5 NYNAS ™ base stock 130 OIL available from Nynas AB Lindetorpsvägen 7, Stockholm, Sweden TBM-6 96-69-5 LOWINOX ™ TBM-6 - 4,4′-thiobis(2-t-butyl-5-, methylphenol) AH25 79-74-3 LOWINOX ™ AH25 - 2,5-di-tert-amyl-hydroquinone TBC 98-29-3 Tert-Butyl Catechol L92 41556-26-7 LOWILITE ™ 92 - Hindered Amine Light Stabilizer - mixture of decanedioc acid, bis (1,2,2,6,6- pentamethyl-4-piperidinyl) and decanedioc acid, methyl 1,2,2,6,6-pentamethyl-4-piperidinyl ester

[0131] A number of stabilising compositions were prepared simply by blending the individual components in the amounts (all w/w) referenced in Table 2:

TABLE-US-00002 TABLE 2 Process Example A20 A1315 A70 PS30 Nonyl.DPA Booster Oil A 25.0%   0% 0% 65.0%     0% 1.0% PTZ 9.0%.sup.  B 36.0% 10.0% 0% 0% 54.0% 0% 0% 1 30.0% 10.0% 0% 0% 59.0% 1.0% PTZ 0% 2 34.0% 10.0% 0% 0% 51.0% 5.0% TBM-6 0% 3 25.5% 10.0% 0% 0% 59.5% 5.0% AH25 0% 4 29.0% 10.0% 0% 0% 51.0% 10% TBC 0% 5 30.0% 20.0% 0% 0% 45.0% 5.0% L92 0% 6   0% 20.0% 30.0%   0% .sup. 45% 5.0% L92 0% 7 25.0% 20.0% 0% 0% .sup. 45% 8.0% L92 0% 2.0% TBC 8 .sup. 40%   0% 0% 0% .sup. 45% 15% L92 0% 9   0%   0% 40%  0% .sup. 45% 15% L92 0%

[0132] Example A is comparative and corresponds to the VANOX™ 945 stabilising package known in the art. Example B is another comparative example. Examples 1 to 9 are in accordance with the invention.

[0133] Each of the stabilising compositions of examples 1 to 9 were observed to be liquid at atmospheric pressure and a temperature of 25° C.

Preparation of Low Density (20-25 kg/m.sup.3) Foams for Microwave Scorch and Gas Fading

[0134] The antioxidant package Example A (0.45 g) was charged to the VORANOL™ 8010 polyol (100 g) in a 1 litre flask. The mixture was homogenised by agitation at 1900 rpm for 1 minute. To this were added a silicone surfactant (Evonik TEGOSTAB™ B8229, 1.1 g), a mixture of amine catalysts (3:1 Dabco 33LV:Dabco BL11, 0.27 g) and deionised water (5 g). The mixture was further agitated for 30 seconds. Tin 2-ethylhexanoate catalyst (ALDRICH™, 0.25 g) was immediately added and the mass agitated for a further 15 seconds. Finally, toluene di-isocyanate (62.7 g) was added in the flask. After mixing for 10 seconds, the solution was quickly poured into an 18 cm×16 cm×16 cm wooden box lined with a Kraft paper mould and the internal temperature monitored.

Microwave Scorch Test

[0135] A BP210/50 research microwave (Microwave Research and Applications Inc.) was used for the scorch test. Once the foam had reached its maximum internal temperature, it was immediately removed from the wooden box and placed inside the microwave cavity. The microwave was set to operate at 20% maximum power (approximately 1300 W) for 60 s. After microwave irradiation, the foam was removed from the cavity and cured in a convection oven for 30 minutes at 95° C. When cooled, the foam was cut open and the colour of the maximum scorched area measured.

[0136] The above process was repeated but antioxidant package Example A is replaced by Example B, and Examples 1 to 9 in accordance with the invention.

[0137] The results of the microwave scorch test are presented in Table 3. The results are normalised relative to that of comparative Example A and presented as ΔE Ex/ΔE A in accordance with the teaching of US20110230579.

TABLE-US-00003 TABLE 3 ΔE Ex/ΔE A Example A 1 Example B 1.5 Example 1 0.75 Example 2 0.84 Example 3 0.26 Example 4 0.36 Example 5 0.88 Example 6 0.90 Example 7 0.60 Example 8 0.90 Example 9 0.90

[0138] As can be seen, Examples 1 to 9 each outperform the comparative examples in terms of scorch reduction.

[0139] Preparation of High Density (40 kg/m.sup.3) Foams for VDA 278 The antioxidant package Example A (0.9 g) was charged to VORANOL™ 8010 polyol (200 g) in a 1 litre flask. The mixture was homogenised by agitation at 1900 rpm for 1 minute. To this were added a silicone surfactant (Evonik TEGOSTAB™ B8229, 1.2 g), a mixture of amine catalysts (3:1 Dabco 33LV:Dabco BL11, 0.60 g) and deionised water (5 g). The mixture was agitated for a further 30 seconds. Tin 2-ethylhexanoate catalyst (ALDRICH™, 0.45 g) was immediately added and the mass agitated for a further 15 seconds. Finally, toluene di-isocyanate (72.2 pph) was charged in the flask. After mixing for 10 seconds, the mixture was quickly poured into an 18 cm×16 cm×16 cm wooden box lined with a Kraft paper mould and the internal temperature monitored. Once cured (30 minutes at 95° C.) and cooled to room temperature, the foam was cut to prepare a sample (100*100*25 mm).

[0140] The above process was repeated but antioxidant package Example A was replaced by Examples 1 to 5.

VDA 278

[0141] Samples were sent to an independent testing centre (SGS Frenesius, Germany) to determine emissions according to VDA 278 method. The results from VDA 278 are collected in Table 4.

TABLE-US-00004 TABLE 4 Table 4: Results from emission test (according to VDA278). Only the emissions relative to the antioxidant package are quoted. Emissions Example Example Example Example Example Example (ppm) A 1 2 3 4 5 VOC 26 0 0 0 0 0 FOG 237 38 22 86 20 52

[0142] As can be seen, Examples 1 to 5 outperform comparative Example A in terms of emissions. The inventive packages have no contributions to VOC (in accordance with the VDA278 method). In terms of FOG all inventive examples show a significantly lower amount of emissions when compared to Example A.

Gas Fading

[0143] Foams were manufactured following the process described above. Once cured (30 minutes at 95° C.) and cooled to room temperature, the foams were cut to prepare a sample (100*100*25 mm). The process is repeated for Examples 1 to 5.

[0144] Samples were sent to an independent testing centre (Intertek Schweiz, Switzerland) to determine their resistance to discoloration when in contact with nitrous oxide. The test was performed according to AATCC 164. Results are shown in Table 5 below:

TABLE-US-00005 TABLE 5 Results from Gas Fading test (according to AATCC 164) Time in ΔE a* b* oven/min 0 30 60 0 30 60 0 30 60 Example A 0.0 32.1 43.3 −0.2 1.9 4.5 −0.4 31.2 41.7 Example 1 0.0 28.0 42.6 −0.3 1.9 4.5 −0.3 27.0 40.9 Example 2 0.0 27.8 40.3 −0.3 −0.4 1.9 −0.5 26.9 39.0 Example 3 0.0 28.1 41.5 −0.3 −1.2 1.1 −0.3 27.2 40.4 Example 4 0.0 25.4 36.2 −0.2 −1.4 0.3 −0.6 24.5 35.1 Example 5 0.0 29.7 40.9 −0.2 −1.1 1.8 −0.7 28.8 39.7

[0145] As can be seen, all inventive Examples 1 to 5 perform at least as well as the comparative Example A in terms of overall colour (i.e. ΔE) but also in terms of individual colours, i.e. the a* (value representing the colour value on the scale going from green to red) and the b* (going from blue to yellow).

Oxidative Onset Temperature

[0146] Polyol was blended with 4500 ppm of the stabilising composition of Examples 1 to 5 and 5 mg of the mixture was placed in an open DSC pan. After an initial stabilisation of the sample at 30° C. under nitrogen, the temperature was increased by 10° C. per minute under oxygen (200 mL/min) from 30 to 300° C.

[0147] A further comparative example (Example C) was conducted using the same method but in the absence of any stabilising composition in the polyol.

[0148] The oxidative onset temperature was then determined and the results presented in Table 6:

TABLE-US-00006 TABLE 6 Oxidative Onset Temperature of inventive and comparative compositions Average OOT (° C.) Example A (comp.) 202.4 Example C (comp.) 130.6 Example 1 204.2 Example 2 202.3 Example 3 201.7 Example 4 204.7 Example 5 201.8

[0149] As can be seen, all samples containing stabilising composition have a similar OOT and offer significant oxidative protection to the polyol.