ANTIDEGRADANT BLEND

Abstract

The invention concerns an antidegradant blend, comprising: an aminic component comprising a hydroxylamine and/or a hydroxylamine precursor; and an inorganic antioxidant or reducing agent.

Claims

1. An antidegradant blend, comprising: a. an aminic component comprising a hydroxylamine and/or a hydroxylamine precursor; and b. an inorganic antioxidant or reducing agent.

2. The antidegradant blend according to claim 1, wherein the antidegradant blend further comprises one or more of: a phenolic antioxidant, an organic phosphite antioxidant, a sulphur-containing antioxidant, and an anti-acid.

3. (canceled)

4. The antidegradant blend according to claim 1, wherein the inorganic antioxidant or reducing agent is a phosphorus-containing compound and/or a sulphur-containing compound.

5. The antidegradant blend according to claim 1, wherein the inorganic antioxidant or reducing agent is selected from the group consisting of a metal phosphite, a metal hypophosphite, a metal thiosulphate, a metal bisulphite, a metal metabisulphite, a metal hydrosulphite and mixtures thereof.

6. The antidegradant blend according to claim 1, wherein the inorganic antioxidant or reducing agent is a phosphorus-containing compound, a metal phosphite and/or a metal hypophosphite.

7. The antidegradant blend according to claim 6, wherein the inorganic antioxidant or reducing agent is a metal hypophosphite.

8. The antidegradant blend according to claim 1, wherein the inorganic antioxidant or reducing agent is present in an amount of from about 5% to about 25%, by weight of the antidegradant blend; and/or wherein the inorganic antioxidant or reducing agent is a solid at a temperature of about 50° C. or lower, and about 1 atmosphere pressure.

9. The antidegradant blend according to claim 1, wherein the hydroxylamine has the general formula R.sub.xR.sub.yNOH, wherein each R independently denotes an optionally branched hydrocarbyl group having from 1 to 25 carbon atoms.

10. The antidegradant blend according to claim 1, wherein the hydroxylamine precursor is an amine oxide.

11. The antidegradant blend according to claim 10, wherein the amine oxide has the general formula R.sub.xR.sub.yR.sub.zNO, wherein each R independently denotes an optionally branched hydrocarbyl group having from 1 to 25 carbon atoms.

12. The antidegradant blend according to claim 1, wherein the aminic component is a solid at a temperature of about 50° C. or lower, and about 1 atmosphere pressure; and/or wherein the aminic component is present in an amount of from about 1% to about 10%, by weight of the antidegradant blend; and/or wherein the ratio of inorganic antioxidant or reducing agent to aminic component is from from about 2:1 to about 12:1.

13. The antidegradant blend according to claim 2, wherein the antidegradant blend comprises a phenolic antioxidant, and wherein the phenolic antioxidant is a partially hindered phenolic antioxidant or a hindered phenolic antioxidant.

14. The antidegradant blend according to claim 2, wherein the antidegradant blend comprises a phenolic antioxidant, and wherein the phenolic antioxidant is present in an amount of from about 20% to about 45%, by weight of the antidegradant blend.

15. The antidegradant blend according to claim 2, wherein the antidegradant blend comprises an organic phosphite antioxidant, and wherein the organic phosphite antioxidant is present in an amount of from about 30% to about 70%, by weight of the antidegradant blend.

16. The antidegradant blend according to claim 2, wherein the antidegradant blend comprises a sulphur-containing antioxidant, and wherein the sulphur-containing antioxidant comprises one or more thioether groups and/or one or more thioester groups.

17. The antidegradant blend according to claim 16, wherein the sulphur-containing antioxidant is present in an amount of from about 30% to about 70%, by weight of the antidegradant blend.

18. The antidegradant blend according to claim 2, wherein the antidegradant blend comprises an anti-acid, and wherein the anti-acid is present in an amount of from about 8% to about 25%, by weight of the antidegradant blend.

19. The antidegradant blend according to claim 18, wherein the anti-acid is selected from the group consisting of lithium stearate, sodium stearate, calcium stearate, zinc stearate, magnesium stearate, aluminum stearate, zinc oxide, magnesium oxide, titanium dioxide calcium carbonate, hydrotalcite, and mixtures thereof.

20. An antidegradant blend, comprising: a. an aminic component comprising a hydroxylamine and/or a hydroxylamine precursor; b. an inorganic phosphite antioxidant; c. a phenolic antioxidant; and d. an organic phosphite antioxidant.

21. An antidegradant blend, comprising: a. bis(octadecyl)hydroxylamine and/or amines, bis(hydrogenated rape-oil alkyl)methyl, N-oxides, present in an amount of from about 0.1% to about 30% by weight of the antidegradant blend; b. sodium hypophosphite, present in an amount of from about 0.1% to about 40% by weight of the antidegradant blend; c. tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane, present in an amount of from about 1% to about 60% by weight of the antidegradant blend; and d. tris(2,4-di-t-butylphenyl)phosphite, present in an amount of from about 10% to about 90% by weight of the antidegradant blend.

22. (canceled)

23. A polymeric composition, comprising a polymeric base material and an antidegradant blend according to claim 1.

24. The polymeric composition according to claim 23, wherein the antidegradant blend is present in an amount of from about 0.1% to about 1%, by weight of the polymeric composition, and/or wherein the aminic component is present in the polymeric composition in an amount less than about 45 ppm, and/or wherein the polymeric base material is selected from the group consisting of a polyolefin, polystyrene, polyacrylonitrile, a polyacrylate, a polyurethane, a polyamide, a polyester, a polycarbonate, polyvinyl chloride, an elastomer, a rubber, and mixtures, blends, and copolymers thereof.

25. An article manufactured from a polymeric composition according to claim 23.

26. The polymeric composition according to claim 23, having a yellowness index of the polymeric base material, as measured by ASTM D1925, that rises less over five passes through an extruder at 260° C. in air, than that of the same polymeric base material to which an equivalent w/w amount of an equivalent antidegradant blend, absent one or both of component (a) and component (b) has been added.

27. The antidegradant blend according to claim 9, wherein the hydroxylamine is selected from the group consisting of N,N-dibenzylhydroxylamine; N,N-diethylhydroxylamine; N,N-dioctylhydroxylamine; N,N-dilaurylhydroxylamine; N,N-ditetradecylhydroxylamine; N,N-dihexadecylhydroxylamine; N-hexadecyl-N-octadecylhydroxylamine; N-heptadecyl-N-octadecylhydroxylamine; bis(octadecyl)hydroxylamine; and mixtures thereof.

28. The antidegradant blend according to claim 10, wherein the amine oxide is bis(hydrogenated rape-oil alkyl)methyl, N-oxides.

Description

EXAMPLES

Examples 1 to 23

Preparation of the Polymeric Composition

[0126] The polymeric base material was a commercially available polypropylene homopolymer for samples 1 to 4 and 8 to 23, and a polypropylene homopolymer with a lower MFR for samples 5 to 7.

[0127] Numerous antidegradant blends were prepared.

[0128] Table 1 shows the different components that were used in the antidegradant blends.

TABLE-US-00001 TABLE 1 Component Shorthand Type Sodium hypophosphite Na Hyp Inorganic phosphite antioxidant ALKANOX ™ 240 A240 Organic phosphite antioxidant ANOX ™ 20 A20 Phenolic antioxidant IRGASTAB ™ FS042 FS042 Bis(octadecyl)hydroxylamine 65% (CAS 143925-92-2) GENOX ™ EP EP Antioxidant amine oxide (delivers a hydroxylamine on heating) (CAS 204933-93-7)

[0129] Table 2 shows the various antidegradant blends that were prepared. The % amounts shown in the table are % by weight of the overall polymeric composition.

TABLE-US-00002 TABLE 2 Na Hyp A240 A20 FS042 EP Total Sample (%) (%) (%) (%) (%) (%)  1 (Comp) — 0.08 0.04 — — 0.12  2 (Comp) — 0.08 0.04 0.015 — 0.135  3 0.0075 0.08 0.04 0.0075 — 0.135  4 (Comp) 0.015 0.08 0.04 — — 0.135  5 (Comp) — 0.0925 0.0925 0.03 — 0.215  6 0.015 0.0925 0.0925 0.015 — 0.215  7 (Comp) 0.03 0.0925 0.0925 — — 0.215  8 (Comp) — 0.08 0.04 — — 0.12  9 0.015 0.08 0.04 0.015 — 0.15 10 (Comp) — 0.08 0.04 0.03 — 0.15 11 (Comp) 0.03 0.08 0.04 — — 0.15 12 0.01 0.08 0.04 0.02 — 0.15 13 0.02 0.08 0.04 0.01 — 0.15 14 0.025 0.08 0.04 0.005 — 0.15 15 0.015 0.08 0.04 0.005 — 0.14 16 0.0275 0.08 0.04 0.0025 — 0.15 17 0.02 0.08 0.04 0.0025 — 0.1425 18 0.01 0.08 0.04 0.0025 — 0.1325 19 0.025 0.08 0.04 — 0.005 0.15 20 0.015 0.08 0.04 — 0.015 0.15 21 (Comp) — 0.08 0.04 — 0.03 0.15 22 (Comp) — 0.08 0.04 — — 0.12 23 0.0275 0.08 0.04 — 0.0025 0.15

[0130] Samples 1, 2, 4, 5, 7, 8, 10, 11, 21 and 22 are comparative examples, in which samples 1, 8 and 22 represent industry available antidegradant blends. Each of the above-identified antidegradant blends was compounded with the polypropylene base material in an extruder at a temperature of 230° C. under nitrogen to form a polymeric composition.

Colour Stability

[0131] Each of the polymeric compositions referenced in Table 2 were multi-passed through an extruder at 260° C. under air. Extrusion experiments were performed on a 25 mm SS BRABENDER™ extruder. After each pass through the extruder the polymer sample was cooled in a water bath, dried and chipped to give pellets which were analysed and subjected to the same procedure again. The discolouration of the compositions was measured in terms of Yellowness Index using a colorimeter (XRITE™ Color i7) according to YI ASTM D1925. Each YI measurement is the average of 4 measured values. YI values were taken following compounding (pass 0) and after passes 1, 3 and 5. The lower the YI value, the less discolouration of the composition. The results are shown in Table 3.

TABLE-US-00003 TABLE 3 YI Value Sample Pass 0 Pass 1 Pass 3 Pass 5  1 (Comp) −0.26 2.71 5.60 8.03  2 (Comp) −0.23 1.35 3.98 6.27  3 −0.59 −0.45 −0.02 0.90  4 (Comp) −1.10 0.23 1.49 2.28  5 (Comp) 0.01 1.49 4.67 8.44  6 −0.33 0.08 0.08 1.23  7 (Comp) −0.23 1.29 2.47 3.10  8 (Comp) −0.56 1.45 3.93 5.46  9 −0.48 0.45 0.83 1.72 10 (Comp) −0.35 1.01 2.77 4.34 11 (Comp) −1.02 0.09 0.83 1.10 12 −0.74 −0.35 0.19 0.66 13 −0.68 −0.21 0.37 1.08 14 −1.04 −0.31 −0.08 0.32 15 −0.84 −0.53 −0.05 0.56 16 −0.72 −0.64 −0.37 0.02 17 −1.06 −0.25 −0.06 0.80 18 −1.20 −0.48 0.01 0.50 19 −0.95 −0.64 −0.38 0.27 20 −0.71 −0.47 −0.04 0.23 21 (Comp) 0.29 1.84 4.18 5.13 22 (Comp) −0.44 1.72 5.08 6.91 23 −0.96 −0.99 −0.62 −0.14

[0132] From the results, it can be seen that the polymeric compositions stabilised with the antidegradant blends in accordance with the present invention (samples 3, 6, 9, 12 to 20 and 23) show significantly less discolouration than the polymeric compositions stabilised with the industry available antidegradant blends (samples 1, 8 and 22). It has surprisingly been found that the best performance, when using a mixture of sodium hypophosphite and an aminic component along with phenolic and organic phosphite antioxidants, occurs when the blend consists of a smaller proportion of hydroxylamine (1-20%) and a larger proportion of sodium hypophosphite (80-99%). This can most clearly be seen with samples 16 and 23.

Melt Flow Rate

[0133] The melt flow rate of the polymeric composition of samples 1 to 23 was determined following compounding (pass 0) and after pass 5, using a CEAST™ 7026 melt flow tester according to standard test method ASTM D1238L with a temperature of 230° C., a 2.16 kg weight and a 2.095 mm die. An increase in the melt flow rate is indicative of unfavourable degradation of the sample, because it is desirable for the properties of the polymeric composition to be maintained, rather than changed, on processing. The results are shown in Table 4.

TABLE-US-00004 TABLE 4 Melt Flow Rate (g/10 min) Sample Pass 0 Pass 5  1 (Comp) 9.77 14.91  2 (Comp) 9.26 16.35  3 8.85 14.30  4 (Comp) 10.18 16.27  5 (Comp) 2.81 5.57  6 2.34 4.07  7 (Comp) 2.34 4.52  8 (Comp) 8.82 15.40  9 8.94 15.01 10 (Comp) 9.23 17.56 11 (Comp) 9.43 14.39 12 8.63 13.46 13 8.64 14.75 14 8.76 14.23 15 8.82 13.70 16 8.84 14.71 17 9.41 15.00 18 9.09 15.59 19 8.87 14.61 20 8.86 14.64 21 (Comp) 9.31 17.24 22 (Comp) 8.91 15.47 23 8.35 14.63

[0134] From the results it can be seen that the polymeric compositions stabilised using the antidegradant blends according to the present invention (samples 3, 6, 9, 12 to 20 and 23) retained melt flow rate similarly to the polymeric compositions stabilised using industry available antidegradant blends (samples 1, 8, and 22).

Colour Fastness to Burnt Gas Fumes

[0135] The fastness of a polymer and additives to burnt gas fumes is determined on a semi-quantitative basis by exposing the compounded polymer pellets to burnt gas fumes in a chamber at a temperature of 60° C. for a period of 48 hrs and monitoring the discolouration of the compositions in terms of Yellowness Index using a colorimeter at 24 hrly intervals according to the procedure of AATCC 23. The lower the YI value, the less discolouration of the composition. The results are shown in Table 5.

TABLE-US-00005 TABLE 5 YI Value Sample 0 hrs 24 hrs 48 hrs  8 (Comp) −0.53 4.92 7.82  9 −0.45 3.56 5.92 10 (Comp) −0.38 1.05 2.87 11 (Comp) −1.08 3.10 5.44 12 −0.69 2.44 4.52 13 −0.51 3.92 6.81 14 −0.93 2.49 5.00 15 −0.99 4.20 7.44 16 −0.92 4.41 8.26

[0136] From the results, it can be seen that the polymeric compositions stabilised with the antidegradant blend in accordance with the present invention (samples 9 and 12 to 16) show less or equal discolouration to the polymeric compositions stabilised with the comparative blends (samples 8, 10, and 11).

Colour Fastness to Oven Aging

[0137] The fastness of a polymer and additives to oven aging is determined on a semi-quantitative basis by exposing the compounded polymer pellets in a glass petri dish to oven aging at 130° C. for a period of 3 weeks and monitoring the discolouration of the compositions in terms of Yellowness Index using a colorimeter (XRITE™ Color i7) according to YI ASTM D1925 at weekly intervals. The lower the YI value, the less discolouration of the composition. The results are shown in Table 6.

TABLE-US-00006 TABLE 6 YI Value Sample 0 wks 1 wk 2 wks 3 wks  8 (Comp) −0.77 2.08 4.12 5.41 16 −1.16 0.25 1.78 3.41

[0138] From the results, it can be seen that the polymeric composition stabilised with the antidegradant blend in accordance with the present invention (Sample 16) shows less discolouration than the polymeric composition stabilised with the industry available blend (Sample 8).

Examples 24 to 36

Preparation of the Polymeric Composition

[0139] For samples 24 to 30, the polymeric base material was a polypropylene homopolymer from a first source.

[0140] For samples 31 to 34, the polymeric base material was a lower MFR polypropylene homopolymer from a second source.

[0141] For samples 35 and 36, the polymeric base material was a polypropylene homopolymer from a third source.

[0142] Numerous antidegradant blends were prepared.

[0143] Table 7 shows the different components that were used in the antidegradant blends.

TABLE-US-00007 TABLE 7 Component Shorthand Type Sodium hypophosphite Na Hyp Inorganic phosphite antioxidant ALKANOX ™ 240 A240 Organic phosphite antioxidant ANOX ™ 20 A20 Phenolic antioxidant IRGASTAB ™ FS042 FS042 Bis(octadecyl)hydroxylamine 65% (CAS 143925-92-2) DHT-4V DHT Hydrotalcite (CAS 11097-59-9) ULTRANOX ™ 626 U626 Organic phosphite antioxidant ANOX ™ IC-14 IC-14 Phenolic antioxidant Calcium Stearate CaSt Acid scavenger

[0144] Table 8 shows the various antidegradant blends that were prepared. The % amounts shown in the table are % by weight of the overall polymeric composition.

TABLE-US-00008 TABLE 8 Na Hyp A240 A20 FS042 DHT U626 IC-14 CaSt Total Sample (%) (%) (%) (%) (%) (%) (%) (%) (%) 24 (Comp) — 0.08 0.04 — — — — 0.03 0.15 25 0.0023 0.08 0.04 0.0002 — — — 0.03 0.1525 26 0.0046 0.08 0.04 0.0004 — — — 0.03 0.155 27 0.0092 0.08 0.04 0.0008 — — — 0.03 0.16 28 0.005 0.08 0.04 0.0025 — — — 0.03 0.1575 29 0.01 0.08 0.04 0.0025 — — — 0.03 0.1625 30 0.015 0.08 0.04 0.0025 — — — 0.03 0.1675 31 (Comp) — 0.11 0.11 — 0.03 — — — 0.25 32 0.0275 0.11 0.11 0.0025 — — — — 0.25 33 (Comp) — 0.14 — — 0.03 0.063 — — 0.233 34 0.0275 0.14 — 0.0025 — 0.063 — — 0.233 35 (Comp) — 0.1 — — — — 0.05 0.04 0.19 36 0.015 0.1 — 0.0014 — — 0.05 0.04 0.2064

[0145] Samples 24, 31, 33 and 35 are comparative examples which represent industry available antidegradant blends. Each of the above-identified antidegradant blends were compounded with the polypropylene base material in an extruder at a temperature of 230° C. under nitrogen to form a polymeric composition.

Colour Stability

[0146] Each of the polymeric compositions referenced in Table 8 were multi-passed through an extruder at 260° C. under air. Extrusion experiments were performed on a 25 mm SS BRABENDER™ extruder. After each pass through the extruder the polymer sample was cooled in a water bath, dried and chipped to give pellets which were analysed and subjected to the same procedure again. The discolouration of the compositions was measured in terms of Yellowness Index (YI) using a colorimeter (XRITE™ Color i7) according to YI ASTM D1925. YI values were taken following compounding (pass 0) and after passes 1, 3 and 5. The lower the YI values, the less discolouration of the composition. The results are shown in Table 9.

TABLE-US-00009 TABLE 9 YI Value Sample Pass 0 Pass 1 Pass 3 Pass 5 24 (Comp) −0.60 −0.01 0.84 2.19 25 −0.34 0.01 1.10 1.88 26 −0.67 −0.36 0.58 0.99 27 −0.53 −0.45 0.19 0.53 28 −0.67 −0.31 0.15 0.81 29 −0.53 −0.37 0.06 0.61 30 −0.61 −0.19 0.33 0.76 31 (Comp) −0.99 0.69 2.46 3.90 32 0.01 0.96 1.85 2.80 33 (Comp) −2.48 0.17 1.88 3.57 34 −0.45 0.14 1.38 1.70 35 (Comp) −0.78 −0.54 1.04 2.5 36 −0.72 −0.45 0.74 2.05

[0147] From the results, it can be seen that the polymeric compositions stabilised with the antidegradant blends in accordance with the present invention (samples 25 to 30, 32, 34 and 36) show significantly less discolouration than the polymeric compositions stabilised with the respective industry available antidegradant blends (samples 24, 31, 33 and 35).

Melt Flow Rate

[0148] The melt flow rate of the polymeric compositions of samples 24 to 36 was determined following compounding (pass 0) and after pass 5, using a CEAST™ 7026 melt flow tester according to standard test method ASTM D1238L with a temperature of 230° C., a 2.16 kg weight and a 2.095 mm die. An increase in the melt flow rate is indicative of unfavourable degradation of the sample. The results are shown in Table 10.

TABLE-US-00010 TABLE 10 Melt Flow Rate (g/10 min) Sample Pass 0 Pass 5 24 (Comp) 9.22 17.93 25 9.45 16.87 26 9.40 17.25 27 9.56 16.96 28 8.63 16.14 29 9.30 16.45 30 9.49 16.72 31 (Comp) 0.60 1.48 32 0.64 1.44 33 (Comp) 0.57 1.19 34 0.63 1.18 35 (Comp) 19.14 28.54 36 19.19 26.19

[0149] From the results it can be seen that the polymeric compositions stabilised using the antidegradant blends according to the present invention (samples 25 to 30, 32, 34 and 36) retained melt flow rate similarly to the polymeric compositions stabilised using the respective industry available antidegradant blends (samples 24, 31, 33 and 35).

Examples 37 to 41

Preparation of the Polymeric Composition

[0150] The polymeric base material was a polypropylene homopolymer.

[0151] Numerous antidegradant blends were prepared.

[0152] Table 11 shows the different components that were used in the antidegradant blends.

TABLE-US-00011 TABLE 11 Component Shorthand Type Sodium hypophosphite Na HypM Inorganic phosphite antioxidant monohydrate ALKANOX ™ 240 A240 Organic phosphite antioxidant ANOX ™ 20 A20 Phenolic antioxidant IRGASTAB ™ FS042 FS042 Bis(octadecyl)hydroxylamine 65% (CAS 143925-92-2) Disodium phosphite DSP Inorganic phosphite antioxidant pentahydrate

[0153] Table 12 shows the various antidegradant blends that were prepared. The % amounts shown in the table are % by weight of the overall polymeric composition.

TABLE-US-00012 TABLE 12 Na HypM A240 A20 FS042 DSP Total Sample (%) (%) (%) (%) (%) (%) 37 (Comp) — 0.08 0.04 — — 0.15 38 (Comp) — 0.08 0.04 — 0.015 0.135 39 — 0.08 0.04 0.0025 0.015 0.1375 40 0.0075 0.08 0.04 0.0025 — 0.13 41 0.0037 0.08 0.04 0.0025 — 0.1262

[0154] Sample 37 is a comparative example which represents an industry available antidegradant blend. Sample 38 is also a comparative example which does not involve a hydroxylamine component. Each of the above-identified antidegradant blends were compounded with the polypropylene homopolymer base material in an extruder at a temperature of 230° C. under nitrogen to form a polymeric composition.

Colour Stability

[0155] Each of the polymeric compositions were multi-passed through an extruder at 260° C. under air. Extrusion experiments were performed on a 25 mm SS BRABENDER™ extruder. After each pass through the extruder the polymer sample was cooled in a water bath, dried and chipped to give pellets which were analysed and subjected to the same procedure again. The discolouration of the compositions was measured in terms of Yellowness Index (YI) using a colorimeter (XRITE™ Color i7) according to YI ASTM D1925. YI values were taken following compounding (pass 0) and after passes 1, 3 and 5. The lower the YI value, the less discolouration of the composition. The results are shown in Table 13.

TABLE-US-00013 TABLE 13 YI Value Sample Pass 0 Pass 1 Pass 3 Pass 5 37 (Comp) 0.74 2.16 4.34 5.89 38 (Comp) 0.00 1.08 3.29 4.58 39 −0.35 0.66 1.85 2.66 40 0.10 0.12 1.24 2.33 41 0.24 0.51 1.93 2.65

[0156] From the results, it can be seen that the polymeric compositions stabilised with the antidegradant blends in accordance with the present invention (samples 39, 40 and 41) show less discolouration than the polymeric compositions stabilised with the industry available antidegradant blend (Sample 37). The results also highlight the important synergistic effect of the hydroxylamine and inorganic antioxidant in the antidegradant blend—samples 39, 40 and 41 outperform the sample containing only the inorganic antioxidant (sample 38) in terms of reduced discolouration.

Melt Flow Rate

[0157] The melt flow rate of the polymeric composition of samples 37 to 41 was determined following compounding (pass 0) and after pass 5, using a CEAST™ 7026 melt flow tester according to standard test method ASTM D1238L with a temperature of 230° C., a 2.16 kg weight and a 2.095 mm die. An increase in the melt flow rate is indicative of unfavourable degradation of the sample. The results are shown in Table 14.

TABLE-US-00014 TABLE 14 Melt Flow Rate (g/10 min) Sample Pass 0 Pass 5 37 (Comp) 7.93 11.97 38 (Comp) 8.31 13.18 39 8.72 12.99 40 8.65 12.86 41 8.80 12.90

[0158] From the results, it can be seen that the polymeric compositions stabilised using the antidegradant blends according to the present invention (samples 39, 40 and 41) retained melt flow rate similarly to the polymeric composition stabilised using the industry standard antidegradant blend (Sample 37).