Stabilizer Composition

Abstract

The invention provides a stabilising composition for a polyol and/or a polyurethane, comprising: a) a first derivatised phenolic antioxidant having a molecular weight of at least about 400 g/mol and a melting point of less than about 100° C.; b) a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant, which is a solid at ambient conditions; and c) a secondary antioxidant comprising a phosphite and/or a thioester,
and also disclosed is a fire retardant blend comprising the stabilising composition and a fire retardant.

Claims

1. A stabilising composition for a polyol and/or a polyurethane, comprising: i. a first derivatised phenolic antioxidant having a molecular weight of at least about 400 g/mol and a melting point of less than about 100° C.; ii. a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant, which is a solid at ambient conditions; and iii. a secondary antioxidant comprising a phosphite and/or a thioester.

2. The stabilising composition according to claim 1 which is absent any diphenylamine and/or alkylated diphenylamine.

3. The stabilising composition according to claim 1, wherein the contribution to VOC of the first derivatised phenolic antioxidant is less than about 10 ppm and/or wherein the contribution to FOG of the first derivatised phenolic antioxidant is less than about 100 ppm.

4. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant comprises one or more derivatised phenolic antioxidants of formula (I): ##STR00006## wherein n is 1 or 2; wherein R.sub.1 is a linear or branched alkyl group having from 1 to 30 carbons, optionally substituted with one or more ether groups; and wherein R.sub.2 and R.sub.3 are each independently selected from straight or branched chain alkyl groups having from 1 to 5 carbon atoms.

5. The stabilising composition according to claim 4, wherein both R.sub.2 and R.sub.3 are t-butyl groups.

6. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant comprises 3,5-bis(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, C13-15 alkyl esters; a blend of 3,5-bis(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, C13-15 alkyl esters and tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane; octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionate; and/or a blend of octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionate and tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane.

7. The stabilising composition according to claim 1, wherein the first derivatised phenolic antioxidant is present in the stabilising composition in an amount of from about 30 wt. % to about 95 wt. %.

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

9. The stabilising composition according to claim 1, wherein the second derivatised phenolic antioxidant has a molecular weight of lower than about 400 g/mol.

10. The stabilising composition according to claim 1, wherein the second derivatised phenolic antioxidant comprises: i. a mono-hydroxybenzene; and/or ii. a di-hydroxybenzene.

11. The stabilising composition according to claim 1, wherein the second derivatised phenolic antioxidant is present in the stabilising composition in an amount of from about 0.1 wt. % to about 50 wt. %.

12. The stabilising composition according to claim 1, wherein the phosphite comprises one or more alkyl phosphites.

13. The stabilising composition according to claim 1, wherein the secondary antioxidant is present in the stabilising composition in an amount of from about 0.01 wt. % to about 20 wt. %.

14. The stabilising composition according to claim 1 which has a melting point of less than about 100° C.

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

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

17. A stabilising composition for a polyol and/or a polyurethane, comprising: a) a first derivatised phenolic antioxidant having a molecular weight of at least about 400 g/mol effective to provide a contribution to VOC of less than about 10 ppm and/or a contribution to FOG of less than about 100 ppm, and having a melting point of less than about 100° C.; b) a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant, which is a solid at ambient conditions; and c) a secondary antioxidant comprising a phosphite and/or a thioester.

18. A stabilising composition for a polyol and/or a polyurethane, comprising: a) a first derivatised phenolic antioxidant having a contribution to VOC of less than about 10 ppm and/or a contribution to FOG of less than about 100 ppm, and having a melting point of less than about 100° C.; b) a second derivatised phenolic antioxidant having lower steric hindrance than the first derivatised phenolic antioxidant, which is a solid at ambient conditions; and c) a secondary antioxidant comprising a phosphite and/or a thioester.

19. The stabilising composition according to claim 1, which when incorporated into a polyurethane foam causes the foam to undergo, on the application of a microwave scorch test, a colour change ΔE less than that of an equivalent foam into which an equivalent amount of industry-available stabilising composition (optionally any one of industry-available stabilising composition 1, 2, 3 or 4) has been incorporated.

20. The stabilising composition according to claim 1, which when incorporated into a polyurethane foam exhibits a contribution to VOC and/or FOG, as measured according to standard test method VDA 278, less than the contribution exhibited by an equivalent foam into which an equivalent amount of industry-available stabilising composition (optionally any one of industry-available stabilising composition 1, 2, 3 or 4) has been incorporated.

21. A fire retardant blend, comprising: i. a stabilising composition according to claim 1; and ii. a fire retardant.

22. (canceled)

23. A stabilised composition, comprising: a polyol and/or a polyurethane; and the stabilising composition according to claim 1.

24. The stabilised composition according to claim 23, wherein the polyurethane is a polyurethane foam.

25. (canceled)

Description

EXAMPLES

[0137] The individual components of the stabilising compositions investigated herein are outlined in Table 1 below. Hereinafter, the individual components will be referred to using the name given in the ‘component’ column.

TABLE-US-00001 TABLE 1 Com- ponent Component Type CAS No. Description ANOX ™ 1315 (a) 171090- 93-0 3,5-bis(1,1-dimethylethyl)- 4-hydroxy-benzenepropanoic acid, C13-15 alkyl esters ANOX ™ PP18 (a) 2082-79-3 octadecyl-3-(3′,5′-di-t-butyl-4′- hydroxyphenyl) propionate ANOX ™ 20 (a) 6683-19-8 Tetrakismethylene (3,5-di-t- butyl-4-hydroxyhydrocinnamate) methane 4-TBC (b) 98-29-3 4-tertbutyl catechol LOWINOX ™ AH25 (b) 79-74-3 2,5-di-tert-amyl-hydroquinone LOWINOX ™ (b) 90-66-4 2,2′-thiobis(6-t-butyl- TBP-6 4-methylphenol) LOWINOX ™ (b) 96-69-5 4,4′-thiobis(2-t-butyl- TBM-6 5-methylphenol) WESTON ™ TLP (c) 3076-63-9 Trilauryl phosphite WESTON ™ TDP (c) 25448-25-3 Triisodecyl phosphite ZP WESTON ™ 430 ZP (c) 36788-39-3 Tris(dipropyleneglycol) phosphite WESTON ™ 618 (c) 3806-34-6 Distearyl pentaerythritol diphosphite NAUGARD ™ (c) 10595-72-9 Di(tridecyl) thiodipropionate DTDTDP

[0138] Stabilising compositions were prepared by mixing the relative amounts of the components identified in Table 2.

TABLE-US-00002 TABLE 2 Amount (wt. %) ANOX ™ ANOX ™ ANOX ™ 4- LOWINOX ™ LOWINOX ™ Example 1315 PP18 20 TBC AH25 TBP-6 1 79 — 10 10 — — 2 79 — 10 10 — — 3 85 — — — 5 5 4 85 — — — 5 5 5 85 — — — 5 — 6 79.5 — 10 10 — — 7 — 74 15 10 — — Amount (wt. %) WESTON ™ WESTON ™ WESTON ™ NAUGARD ™ Example TLP TDP ZP 618 DTDTDP 1 1 — — — 2 — 1 — — 3 5 — — — 4 — 5 — — 5 5 — — 5 6   0.5 — — — 7 — — 1 —

[0139] In addition to the stabilising compositions in Table 2, the industry-available stabilising compositions identified in Table 3 were also tested.

TABLE-US-00003 TABLE 3 Exam- Component Types ple Designation Description Present A Industry- Phenolic antioxidant Only (a) (Comp) available according to component type Stabilising (a) + lactone (CAS Composition 1 1261240-30-5) B Industry- Bisphenolic antioxidant (a) + (b), (Comp) available stabiliser of formula (II) not (c) Stabilising described above + vitamin E Composition 2 (CAS 59-02-9) C Industry- 7:1:1 blend hindered Only (c) (Comp) available phenolic (CAS 125643-61-0): ((b) is not Stabilising phosphite (CAS 145650-60- present Composition 3 8): 3-(2-acetyl-5-isooctylphenyl)- and the 5-isooctylbenzofuran-2-one phenolic (CAS 216698-07-6) antioxidant has Mw <400) D Industry- 2:1 blend phenolic antioxidant None (Comp) available (CAS 125643-61-0) + (the Stabilising aminic antioxidant (CAS phenolic Composition 4 68411-46-1) antioxidant has Mw <400)
Preparation of Medium Density (20-25 kg/m.sup.3) Polyurethane Foams

[0140] For the stabilising compositions of examples 1 to 5 and 7 outlined in Table 2 and examples A to D outlined in Table 3, 0.45 g of the stabilising composition was charged to 100 g of a 3500 Mw polyol in a 1 litre flask. The mixture was homogenised by agitation at 1900 rpm for 1 minute. To this mixture, 1.1 g of TEGOSTAB™ B8229 (Evonik), 0.27 g of a mixture of amine catalysts (3:1 DABCO™ 33LV:DABCO™ BL11), and 5 g of deionised water were added and the reaction mixture agitated for 30 seconds. 0.25 g of tin(II) ethylhexanoate (Aldrich) was immediately added and the reaction mixture agitated for a further 15 seconds. 62.7 g of toluene di-isocyanate was added to the flask and mixed for 10 seconds. The resulting mixture was quickly poured into an 18 cm×16 cm×16 cm wooden box lined with a Kraft paper mould and the internal temperature was monitored during foaming.

Microwave Scorch Test

[0141] 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 the desired period of time. 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 using an X-RITE™ ColorEye 7000A colourimeter.

[0142] The results of the microwave scorch test are presented in Table 4 below. The results are normalised relative to that of comparative example D and presented as ΔE Ex/ΔE D in accordance with the teaching of US 2011/0230579, where ΔE is the change in colour.

TABLE-US-00004 TABLE 4 Example ΔE Ex/ΔE D 1 0.66 2 0.75 3 0.69 4 0.30 5 0.66 7 1.02 A 1.5 B 2.2 C 1.5 D 1

[0143] From the results it can be seen that examples 1 to 5, and 7 in accordance with the present invention all outperform the comparative examples in terms of scorch reduction.

Gas Fading Test

[0144] For the stabilising compositions of examples 1, 3, 4, 5 and 7 outlined in Table 2 and examples A and D outlined in Table 3, foams were prepared as outlined under section ‘Preparation of Medium Density (20-25 kg/m.sup.3) Polyurethane Foams’. The foams were cured at 95° C. for 30 minutes and then cooled to room temperature. The foams were cut to prepare samples having the dimensions 100 mm×100 mm×25 mm.

[0145] Samples were tested to determine their resistance to discolouration when in contact with nitrous oxide. The test was performed according to standard test method AATCC 164—the colour was recorded after 0, 30 and 60 minutes in the oven. The colour was measured using an X-RITE™ Color i7 colourimeter. The results of the gas fading test are shown in Table 5 below.

TABLE-US-00005 TABLE 5 Time ΔE a* b* (min) 0 30 60 0 30 60 0 30 60 A 0.0 3.0 8.4 0.8 0.4 0.0 −0.2 2.7 8.0 D 0.0 6.4 12.4 0.8 0.2 −1.2 −0.2 5.9 12.0 1 0.0 3.5 5.2 0.8 0.6 0.6 −0.4 3.1 4.8 3 0.0 2.7 6.8 0.8 0.8 0.8 −0.1 2.5 6.6 4 0.0 2.6 5.9 0.8 1.1 1.3 −0.8 1.4 3.7 5 0.0 2.4 3.8 0.9 0.9 1.2 −0.1 2.0 3.5 7 0.0 4.8 5.7 0.8 0.4 0.8 0.1 4.0 5.1

[0146] From the results it can be seen that the examples in accordance with the present invention all perform at least as well as the industry-available stabilising compositions of examples A and D in terms of overall colour change (ΔE) and 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* value (representing the colour value on the scale going from blue to yellow). Examples 1, 3, 4, 5 and 7 perform better than the industry-available stabilising compositions.

Preparation of High Density (40 kg/m.sup.3) Polyurethane Foams

[0147] For the stabilising compositions of examples 1 to 5 outlined in Table 2 and examples A to D outlined in Table 3, 0.9 g of the stabilising composition was charged to 200 g of polyol in a 1 litre flask. The mixture was homogenised by agitation at 1900 rpm for 1 minute. To this mixture, 1.2 g of TEGOSTAB™ B8229 (Evonik), 0.60 g of a mixture of amine catalysts (3:1 DABCO™ 33LV:DABCO™ BL11), and 5 g of deionised water were added and the reaction mixture agitated for 30 seconds. 0.45 g of tin(II) ethylhexanoate (Aldrich) was immediately added and the reaction mixture agitated for a further 15 seconds. 72.2 php of toluene di-isocyanate was added to the flask and mixed for 10 seconds. The resulting mixture was quickly poured into an 18 cm×16 cm×16 cm wooden box lined with a Kraft paper mould and the internal temperature was monitored during foaming.

[0148] The resulting foam was cured at 95° C. for 30 minutes and then cooled to room temperature. The foam was cut to prepare a sample having the dimensions 100 mm×100 mm×25 mm.

Emissions Testing According to Standard Test Method VDA 278

[0149] The foam samples were tested to determine emissions in accordance with standard test method VDA 278, issued by “Verband Der Automobilindustrie” in October 2011, the internationally accepted, standardised test procedure for the quantitative analysis of volatile compounds. The results are shown in Table 6 below.

TABLE-US-00006 TABLE 6 Emissions (ppm)* Example A B C D 1 2 3 4 5 VOC 1 5 23 50 0 0 0 0 0 FOG 60 10 237 900 2 4 4 4 3 *only the emissions attributable to the stabilising compositions are quoted

[0150] From the results it can be seen that examples 1 to 5 in accordance with the present invention outperform industry-available stabilising compositions of examples A to D. The stabilising compositions in accordance with the present invention have negligible contribution to VOC, and a significantly lower contribution to FOG emissions compared to industry—available stabilising compositions, particularly examples C and D.

Colour Stability in Non-Halogenated Fire Retardants

[0151] The colour stability of the stabilising compositions of examples 1, 2, and 6 was tested in a fire retardant and compared to the colour stability of industry-available stabilising composition represented by example D.

[0152] A sample of the fire retardant tris(1,3-dichloro-2-propyl) phosphate (TDCPP-CAS 13674-87-8) was loaded with 3% by weight of the stabilising composition. The resulting blend was divided into two separate samples. One sample was kept at room temperature for 10 days, whilst the other was kept at 60° C. in an oven for 10 days. Following this, the APHA colour value was measured using a LOVIBOND™ PFXi-195 colourimeter.

[0153] The results are shown in Table 7 below.

TABLE-US-00007 TABLE 7 APHA Colour Example 1 2 6 D Trialkyl phosphite loading (%) 1 1 0.5 N/A Day 0 48 25 59 99 Day 10 RT, light 45 38 50 160 60° C. 60 56 69 >500 (GV: 2.6)

[0154] From the results it can be seen that the stabilising compositions of examples 1, 2, and 6 perform significantly better with regards to colour stability in the fire retardant compared to industry-available stabilising composition of example D (amine-based).

Colour Stability of Stabilising Compositions with LOWINOX™ AH25

[0155] Stabilising compositions all involving LOWINOX™ AH25 were prepared by mixing the relative amounts of the components identified in Table 8.

TABLE-US-00008 TABLE 8 Amount (wt. %) LOWINOX ™ WESTON ™ LOWINOX ™ ANOX ™ Example AH25 430 ZP TBM-6 1315 8 (Comp) 5 — — 95  9 5 10 — 85 10 5 10 10 75 11 (Comp) 5 — 10 85

[0156] Discolouration of each of the stabilising compositions was investigated.

[0157] A sample of each of the stabilising compositions was prepared under nitrogen and placed in an oven at 40° C. for the required amount of time (1 day, 1 month and 3 months). After the allotted time, the colour value was measured using a LOVIBOND™ PFXi-195 colourimeter.

[0158] The results are shown in Table 9.

TABLE-US-00009 TABLE 9 Colour Value Example Day 1 (APHA) 1 Month (APHA) 3 Months (Gardner) 8 (Comp) 345 356 2.7  9 423 348 1.0 10 442 305 0.1 11 (Comp) 456 497 3.1

[0159] From the results it can be seen that the stabilising compositions according to the present invention (examples 9 and 10) have better colour stability compared to stabilising compositions which do not include the phosphite secondary antioxidant. Example 10 highlights the synergistic effect of the combination of LOWINOX™ AH25 with LOWINOX™ TBM-6 and the phosphite antioxidant as discolouration is further reduced.