Nitrile polymer vulcanizate and process for the production thereof

1. A vulcanizable composition comprising:

(i) a nitrile polymer;

(ii) a filler;

(iii) a metal salt of a secondary amine, wherein the metal is selected from groups 1 and 2 of the periodic system of the elements according to IUPAC 1985, wherein the secondary amine is 4,4′-bis-α,α-dimethylbenzyl-diphenylamine, octylated diphenyl amine, styrenated diphenyl amine, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, butylated/octylated diphenylamine, or 2,2,4-trimethyl-1,2-dihydroquinoline polymer;

(iv) a vulcanization system; and

(v) optionally an additive selected from the group consisting of a strong base, a salt of strong base and a weak acid, a salt of a weak acid, a carbodiimide, a polycarbodiimide and mixtures thereof.

2. The vulcanizable composition according to claim 1 , wherein the nitrile polymer comprises a copolymer of a conjugated diene and an unsaturated nitrile.

3. The vulcanizable composition according to claim 2 , wherein the copolymer further comprises an unsaturated mono- or di-carboxylic acid or derivative thereof.

4. The vulcanizable composition according to claim 2 , wherein the copolymer is hydrogenated.

5. The vulcanizable composition defined in claim 4 , wherein the copolymer comprises a residual carbon-carbon double bond unsaturation of less than 30 mole percent.

6. The vulcanizable composition according to claim 1 , wherein the metal is lithium, sodium, potassium or calcium.

7. The vulcanizable composition according to claim 6 , wherein the metal is sodium.

8. The vulcanizable composition according to claim 1 , wherein the filler comprises carbon black.

9. The vulcanizable composition according to claim 1 , wherein the salt of a strong base and a weak acid has a pk a in the range of from 10.0 to 12.0.

10. The vulcanizable composition according to claim 9 , wherein the salts is sodium carbonate, sodium acetate, sodium phosphate, potassium carbonate, sodium stearate, sodium EDTA and mixtures thereof.

11. The vulcanizable composition according to claim 10 , wherein the salts is sodium carbonate.

12. The vulcanizable composition according to claim 1 , wherein the vulcanization system comprises a peroxide compound.

13. A process for producing a nitrile polymer vulcanizate comprising the step of admixing a polymer composition comprising:

(i) a nitrile polymer;

(ii) a filler;

(iii) a metal salt of a secondary amine with the metal being selected from groups 1-2 of the periodic system of the elements (IUPAC 1985) wherein the secondary amine is 4,4′-bis-α,α-dimethylbenzyl-diphenylamine, octylated diphenyl amine, styrenated diphenyl amine, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, butylated/octylated diphenylamine, or 2,2,4-trimethyl-1,2-dihydroquinoline polymer;

(iv) a vulcanization system; and

(v) optionally an additive selected from the group comprising: a strong base, a salt of strong base and a weak acid, a salt of a weak acid, a carbodiimide, a polycarbodiimide and mixtures thereof.

14. The process according to claim 13 , wherein the polymer composition is maintained at a temperature in the range of from 135° to 200° C.

15. A vulcanizable composition comprising:

(i) a nitrile polymer;

(ii) a filler;

(iii) a metal salt of a secondary amine, where the metal is selected from groups 1 and 2 of the periodic system of the elements according to IUPAC 1985, wherein the secondary amine is 4,4′-bis-α,α-dimethylbenzyl-diphenylamine, octylated diphenyl amine, styrenated diphenyl amine, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, butylated/octylated diphenylamine, or 2,2,4-trimethyl-1,2-dihydroquinoline polymer;

(iv) a vulcanization system; and

(v) optionally an additive selected from the group consisting of a strong base, a salt of strong base and a weak acid, a salt of a weak acid, a carbodiimide, a polycarbodiimide and mixtures thereof.