Composition

Abstract

The present invention provides a stabilising composition, comprising: a) a first phenolic antioxidant comprising one or more phenolic compounds having the structure of formula (I): ##STR00001##  wherein R.sub.1 is a linear or branched alkyl group having from 12 to 20 carbon atoms; and b) one or more second phenolic antioxidants independently selected from:  a mono-hydroxybenzene having lower steric hindrance than the first phenolic antioxidant;  a di-hydroxybenzene; and/or  a tri-hydroxybenzene.

Claims

1. A stabilizing composition, comprising: a) a first phenolic antioxidant comprising one or more phenolic compounds having the structure of formula (I): ##STR00016## wherein R.sub.1 is a linear or branched alkyl group having from 12 to 20 carbon atoms; and b) one or more second phenolic antioxidants comprising a di-hydroxybenzene comprising 4-tert-butylcatechol, benzene-1,2-diol, or benzene-1,3-diol.

2. The stabilizing composition of claim 1, wherein the di-hydroxybenzene comprises 4-tert-butylcatechol or benzene-1,2-diol.

3. The stabilizing composition of claim 1, wherein the di-hydroxybenzene comprises benzene-1,2-diol.

4. The stabilizing composition of claim 1, wherein the di-hydroxybenzene comprises 4-tert-butylcatechol.

5. The stabilizing composition of claim 1, wherein the one or more second phenolic antioxidants is present in an amount of from about 1 to about 50 wt. %, based on the total weight of the stabilizing composition.

6. The stabilizing composition of claim 1, wherein the one or more second phenolic antioxidants are present in the stabilizing composition in an amount of from about 1 to about 35 wt. %, based on the total weight of the stabilizing composition.

7. The stabilizing composition of claim 1, wherein the one or more second phenolic antioxidants are present in the stabilizing composition in an amount of from about 5 to about 30 wt. %, based on the total weight of the stabilizing composition.

8. The stabilizing composition of claim 1, wherein the one or more second phenolic antioxidants are present in the stabilizing composition in an amount of from about 10 to about 25 wt. %, based on the total weight of the stabilizing composition.

9. A stabilized composition, comprising: a) a polyol and/or a polyurethane; and b) a stabilizing composition of claim 1.

10. The stabilized composition of claim 9, wherein the polyol is present and comprises a polyether polyol and/or a polyester polyol.

11. The stabilized composition of claim 9, wherein the polyol is present with the polyurethane, and comprises a polyether polyol and/or a polyester polyol.

12. The stabilized composition of claim 9, wherein the polyurethane is present and comprises a polyurethane foam.

13. The stabilized composition of claim 9, wherein the amount of stabilizing composition is present from about 0.01 to about 10% by weight of the polyol and/or a polyurethane.

14. The stabilized composition of claim 9, wherein the amount of stabilizing composition is present from about 0.01 to about 5%, by weight of the polyol and/or a polyurethane.

15. The stabilized composition of claim 9, wherein the amount of stabilizing composition is present from about 0.01 to about 2%, by weight of the polyol and/or a polyurethane.

16. The stabilizing composition of claim 1, wherein the stabilizing composition does not contain a benzofuranone-based booster component.

17. The stabilizing composition of claim 1, wherein the stabilizing composition does not contain an amine-containing antioxidant.

Description

EXAMPLES

(1) Table 1 outlines details relating to different stabilising components used in the examples. Hereinafter, the stabilising components will be referred to using the name given in the ‘component’ column.

(2) TABLE-US-00001 TABLE 1 CAS Component Type No. Description Structure ANOX ® 1315 Phenolic 171090- 93-0 C13-C15 linear and branched alkyl esters of 3-(3′-5′-di-t-butyl-4′- hydroxylphenyl)propionic acid 4-TBC Phenolic booster 98-29-3 4-tertbutyl catechol LOWINOX ® TBP-6 Phenolic booster 90-66-4 2,2′-thiobis(6-t-butyl-4- methylphenol) 0 IRGANOX ® 1135 (BASF) Phenolic 125643- 61-0 Benzenepropanoic acid, 3,5-bis(1,1-dimethyl- ethyl)-4-hydroxy-,C7-C9 branched alkyl esters IRGAFOS ® 38 (BASF) Phosphite 145650- 60-8 Bis(2,4-di-tert.-butyl-6- methylphenyl)-ethyl- phosphite PS-1 (BASF) Booster — 3-(2-acetyl-5- isooctylphenyl)-5- isooctylbenzofuran-2- one NAUGARD ® PS-30 Amine 68411- 46-1 Butylated, octylated diphenylamine LOWINOX ® TBM-6 Phenolic booster 96-69-5 4,4′-thiobis(2-t-butyl-5- methylphenol)

(3) The following stabilising compositions are commercially available and may be considered as industry bench-mark stabilising compositions: IRGASTAB® PUR68 (BASF)—7:1:1 blend of IRGANOX® 1135, IRGAFOS® 38 and a benzofuran-2-one (PS-1)

Examples 1 to 4

(4) Preparation of Stabilised Low Density Polyurethane Foams

(5) Three stabilising compositions with the stabilisers shown in Table 2, were prepared by mixing the relative amounts of the stabilisers. The stabilising compositions of examples 1 and 2 had a phenolic component and a phenolic booster component, and are in accordance with the present invention. Example 3 represents an industry bench-mark stabilising composition involving a phenolic component, a phosphite component and a non-phenolic ‘booster’ component, and is a comparative example. Example 4 represents an industry bench-mark stabilising composition involving a phenolic component and an aminic component, and is a comparative example.

(6) TABLE-US-00002 TABLE 2 Amount (per hundred parts Example Stabiliser polyol) 1 ANOX ® 1315 0.405 4-TBC 0.045 2 ANOX ® 1315 0.405 LOWINOX ® TBM-6 0.045 3 IRGANOX ® 1135 0.35 IRGAFOS ® 38 0.05 PS-1 0.05 4 ANOX ® 1315 0.225 NAUGARD ® PS-30 0.225

(7) For each of the stabilising compositions outlined in Table 2, the amount shown was dissolved in 104.85 g of a polyether polyol (AT300 manufactured by Mitsui). To this, 0.79 g of TEGOSTAB® B8229 (Evonik), 0.21 g of a solution containing DABCO® 33LV (Air Products) and DABCO® BL11 (Air Products), and 6.53 g of deionised water were added and the reaction mixture stirred vigorously for 30 seconds at 1500 rpm. 0.27 g of tin(II) ethylhexanoate (Sigma Aldrich) was added and the reaction mixture stirred vigorously for 15 seconds at 1500 rpm. 83.2 g of isocyanate (Bayer, 2,4-toluylene di-isocyanate and 2,6-toluylene di-isocyanate mixture) was added and the reaction mixture stirred vigorously for 10 seconds at 1500 rpm.

(8) The resulting mixture was poured into a 25 cm×25 cm×25 cm box lined with Kraft paper and the exothermic temperature was measured during foaming to a foam block.

(9) Each foam block was either a) cured at 95° C. in a conventional oven for 30 minutes and allowed to cool to ambient temperature, or b) heated in a microwave oven at a pre-determined power level for a pre-determined time to induce temperatures that represented those experienced in polyurethane foam production, then cured at 95° C. in a conventional oven. The density of the foam block was roughly 20 kg/m.sup.3.

(10) Foam blocks with the stabilising compositions of examples 1 to 3 were subjected to step b) above and the discolouration of the foam due to scorch was measured. The discolouration was measured in terms of Yellowness Index (YI). The lower the YI value, the less discolouration and hence the less scorch. The higher the YI value, the greater discolouration and hence the higher scorch. The results are shown in Table 3.

(11) TABLE-US-00003 TABLE 3 Example YI Value 1 24.51 2 28.88 3 19.69

(12) It can be seen from the results that the YI values of the foam blocks stabilised with the stabilising compositions according to the present invention (examples 1 and 2) are comparable to YI value of the foam block stabilised with the industry bench-mark stabilising composition (Example 3).

(13) Separate foam blocks with the stabilising compositions of examples 1 to 4 were cured at 95° C. in a conventional oven for 30 minutes and allowed to cool to ambient temperature (step a) above). The foam blocks were then exposed to NOx gases at a temperature of 60° C. in accordance with standard test method AATCC Test Method 23-2005. The discolouration after 2 hours, 3 hours and 4 hours was measured in terms of Yellowness Index (YI). The results are shown in Table 4.

(14) TABLE-US-00004 TABLE 4 Example YI Value (2 h) YI Value (3 h) YI Value (4 h) 1 31.81 37.35 41.73 2 47.20 54.38 61.60 3 27.06 37.70 43.40 4 44.58 52.64 58.25

(15) Stabilising compositions are known to contribute adversely to discolouration of polyurethane foams on exposure to pollutant gases, in particular NOx gases. It can be seen from the results that the YI values at 2 hours, 3 hours and 4 hours for the foam blocks stabilised with stabilising compositions according to the present invention, (examples 1 and 2) are comparable to YI values of the foam blocks stabilised with the industry bench-mark stabilising compositions (examples 3 and 4).

Examples 5 to 14

(16) Oxidation Induction Temperature of Stabilised Polyether Polyols

(17) Stabilising compositions according to the present invention have also been shown to stabilise polyether polyols (the precursor to polyurethane foams).

(18) Ten polyether polyol samples were stabilised using the stabilising compositions shown in Table 5. Examples 5 to 11 used stabilising compositions in accordance with the present invention. Examples 12 to 14 used an industry bench-mark stabilising composition involving a phenolic component, a phosphite component and a non-phenolic ‘booster’ component, and are comparative examples.

(19) Differential scanning calorimetry was used to determine the Oxidation Induction Temperature (OIT) of the stabilised polyether polyol samples. The OIT was measured according to standard test method ASTM 3895, and did not take into account pre-oxidation events. Differential scanning calorimetry was carried out in oxygen and the temperature ranged from 25° C. to 300° C., increasing at a rate of 10° C. per minute. The OIT results are shown in Table 5.

(20) TABLE-US-00005 TABLE 5 Amount (per hundred parts Example Stabiliser polyol) OIT (° C.)  5 ANOX ® 1315 0.27 184.68 4-TBC 0.03  6 ANOX ® 1315 0.405 190.79 4-TBC 0.045  7 ANOX ® 1315 0.54 194.28 4-TBC 0.06  8 ANOX ® 1315 0.27 180.01 LOWIOX ® TBP-6 0.03  9 ANOX ® 1315 0.405 184.52 LOWINOX ® TBM-6 0.045 10 ANOX ® 1315 0.54 189.15 LOWINOX ® TBP-6 0.06 11 ANOX ® 1315 0.54 195.32 LOWINOX ® TBM-6 0.06 12 IRGANOX ® 1135 0.23 183.03 IRGAFOS ® 38 0.03 PS-1 0.03 13 IRGANOX ® 1135 0.35 190.06 IRGAFOS ® 38 0.05 PS-1 0.05 14 IRGANOX ® 1135 0.47 194.40 IRGAFOS ® 38 0.07 PS-1 0.07

(21) From the results it can be seen that the polyether polyol samples stabilised with the stabilising composition according to the present invention (examples 5 to 11) had comparable OIT values to those samples stabilised with the industry bench-mark stabilising composition (examples 12 to 14). OIT values are indicative of the likely scorch performance.

Examples 15 to 23

(22) Discolouration of Stabilised Polyether Polyols

(23) Nine polyether polyol samples were stabilised using the stabilising compositions outlined in Table 6. Examples 15 to 20 used stabilising compositions in accordance with the present invention. Examples 21 to 23 used an industry bench-mark stabilising composition involving a phenolic component, a phosphite component and a non-phenolic ‘booster’ component, and are comparative examples.

(24) Accelerated heat aging was carried out on each of the polyether polyol samples for 4 hours at 180° C., and the discolouration was measured using the Yellowness Index (YI).

(25) TABLE-US-00006 TABLE 6 Amount (per hundred parts YI Value Example Stabiliser polyol) (4 h) 15 ANOX ® 1315 0.27  6.66 4-TBC 0.03 16 ANOX ® 1315 0.405 10.56 4-TBC 0.045 17 ANOX ® 1315 0.54 15.84 4-TBC 0.06 18 ANOX ® 1315 0.27  8.05 LOWINOX ® TBP-6 0.03 19 ANOX ® 1315 0.405 10.36 LOWINOX ® TBP-6 0.045 20 ANOX ® 1315 0.54 10.97 LOWINOX ® TBM-6 0.06 21 IRGANOX ® 1135 0.23  2.91 IRGAFOS ® 38 0.03 PS-1 0.03 22 IRGANOX ® 1135 0.35  4.00 IRGAFOS ® 38 0.05 PS-1 0.05 23 IRGANOX ® 1135 0.47  4.37 IRGAFOS ® 38 0.07 PS-1 0.07

(26) From the results it can be seen that the polyether polyol samples stabilised with the stabilising composition according to the present invention (examples 15 to 20) showed comparable discolouration to those samples stabilised with the industry bench-mark stabilising composition (examples 21 to 23).

Examples 24 to 26

(27) Viscosity and Thermogravimetric Analysis of Stabilising Compositions

(28) Three stabilising compositions with the stabilisers shown in Table 7, were prepared by mixing the relative amounts of the stabilisers.

(29) TABLE-US-00007 TABLE 7 Example Stabiliser Relative Amounts 24 ANOX ® 1315 0.9 4-TBC 0.1 25 ANOX ® 1315 0.9 LOWINOX ® TBP-6 0.1 26 IRGANOX ® 1135 0.45 IRGAFOS ® 38 0.05 PS-1 0.05

(30) The dynamic viscosity for each of the stabilising compositions was determined using a Brookfield viscometer. The results are shown in Table 8.

(31) TABLE-US-00008 TABLE 8 Dynamic Viscosity Example 25° C. 40° C. 60° C. 24  302  88 28 25  392 125 40 26 1060 250 53

(32) It is important for the stabilising compositions to be liquids under operating conditions in order to be easily handled. From the results it can be seen that the stabilising compositions according to the present invention (examples 24 and 25) have viscosities comparable to the industry bench-mark stabilising composition (Example 26).

(33) Thermogravimetric analysis of each of the stabilising compositions was determined using standard test method ASTM E1131. The results are shown in Table 9.

(34) TABLE-US-00009 TABLE 9 ° C. Example 10% wt. loss 25% wt. loss 50% wt. loss 24 179.87 247.87 280.02 25 218.82 253.21 278.89 26 206.90 228.78 247.64

(35) Thermogravimetric analysis indicates the thermal stability of a stabilising composition. The thermal stability of a stabilising composition is important due to the high temperatures e.g. greater than 170° C., that may be experienced during polyurethane production.

(36) From the results it can be seen that the stabilising compositions according to the present invention (examples 24 and 25) have comparable thermal stability to the industry bench-mark stabilising composition (Example 26).