Compositions that can be vulcanized and that are based on ethylene/vinyl acetate copolymers containing epoxy groups

1. A vulcanizable rubber composition comprising:

(a) at least one ethylene-vinyl acetate copolymer containing epoxy groups, which comprises: at least 50% by weight of copolymerized vinyl acetate monomer, less than 20% by weight of copolymerized monomer which contains epoxy groups, and a balance by weight of copolymerized ethylene monomer, based on the weight of the ethylene-vinyl acetate copolymer containing epoxy groups; and

(b) at least one carboxylated nitrile rubber comprising repeat units derived from at least one conjugated diene, at least one α,β-unsaturated nitrile, and one or more further copolymerizable monomers containing carboxyl groups,

wherein a ratio by weight of (a) to (b) is 1:3 to 3:1.

2. The vulcanizable composition according to claim 1 , wherein:

the composition contains no further cross-linking agents for vulcanization; and

the monomer which contains epoxy groups is selected from the group consisting of 2-ethylglycidyl acrylate, 2-ethylglycidyl methacrylate, 2-(n-propyl)glycidyl acrylate, 2-(n-propyl)glycidyl methacrylate, 2-(n-butyl)glycidyl acrylate, 2-(n-butyl)glycidyl methacrylate, glycidylmethyl acrylate, glycidyl methacrylate, glycidylmethyl methacrylate, glycidyl acrylate, (3′,4′-epoxyheptyl)-2-ethyl acrylate, (3′,4′-epoxyheptyl)-2-ethyl methacrylate, 6′,7′-epoxyheptyl acrylate, 6′,7′-epoxyheptyl methacrylate, allyl glycidyl ether, allyl 3,4-epoxyheptyl ether, 6,7-epoxyheptyl allyl ether, vinyl glycidyl ether, vinyl 3,4-epoxyheptylether, 3,4-epoxyheptyl vinyl ether, 6,7-epoxyheptyl vinyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and 3-vinylcyclohexene oxide.

3. The vulcanizable composition according to claim 1 , wherein:

the at least one ethylene-vinyl acetate copolymer containing epoxy groups (a) comprises: at least 50% by weight of copolymerized vinyl acetate monomer, less than 15 wt % of copolymerized monomer which contains epoxy groups, and a balance by weight of copolymerized ethylene monomer, based on the weight of the ethylene-vinyl acetate copolymer containing epoxy groups; and

the at least one carboxylated nitrite rubber (b) comprises 1-20 parts by weight of the monomers containing carboxyl groups based on 100 parts by weight of the nitrile rubber which derives from acrylonitrile and the conjugated diene monomers.

4. The vulcanizable composition according to claim 3 , wherein the monomers which contain carboxyl groups are of general formula (II)

in which:

R 1 , R 2 , R 3 are the same or different and are each H, a linear or branched, saturated or mono- or polyunsaturated alkyl radical, a saturated or mono- or polyunsaturated carbo- or heterocycle radical, aryl, heteroaryl, arylalkyl, heteroarylalkyl, alkoxy, aryloxy, heteroaryloxy, amino, amido, carbamoyl, alkylthio, arylthio, sulphanyl, thiocarboxyl, sulphinyl, sulphono, sulphino, sulpheno, sulphonic acids, sulphamoyl, hydroxyimino, alkoxycarbonyl, F, Cl, Br, I, hydroxyl, phosphonato, phosphinato, silyl, silyloxy, nitrile, borates, selenates, carbonyl, oxycarbonyl, oxysulphonyl, oxo, thioxo, epoxy, cyanates, thiocyanates, isocyanates, thioisocyanates, isocyanides or carboxyl groups,

n is 0 or 1,

X is O, O(CR 2 ) p , (CR 2 ) p O, C(═O)O, C(═O)O(CR 2 ) p , C(═O)NR, (CR 2 ) p , N(R), N(R)(CR 2 ) p , P(R), P(R)(CR 2 ) p , P(═O)(R), P(═O)(R)(CR 2 ) p , S, S(CR 2 ) p , S(═O), S(═O)(CR 2 ) p , S(═O) 2 (CR 2 ) p or S(═O) 2 , where R in these radicals has the meaning defined for R 1 -R 3 and p has values between 1 and 1000,

m is 0 or 1, and

Y are the same or different and are each a linear or branched, saturated or mono- or polyunsaturated alkyl radical, a saturated or mono- or polyunsaturated carbo- or heterocyclyl radical, aryl, heteroaryl, arylalkyl, heteroarylalkyl or alkoxyaryl radical.

5. The vulcanizable composition according to claim 4 , wherein the at least one carboxylated nitrile rubber (b) comprises 2 to 10 parts by weight of the monomers containing carboxyl groups based on 100 parts by weight of the nitrile rubber which derives from acrylonitrile and the conjugated diene monomers.

6. The vulcanizable composition according to claim 5 , wherein the at least one carboxylated nitrile rubber (b) is fully or partly hydrogenated.

7. The vulcanizable composition according to claim 5 or 6 , wherein the ratio by weight of (a) to (b) is from 1:2 to 2:1.

8. The vulcanizable composition according to claim 1 , wherein the at least one ethylene-vinyl acetate copolymer containing epoxy groups (a) comprises: at least 50% by weight of copolymerized vinyl acetate monomer, less than 15 wt % of copolymerized monomer which contains epoxy groups, and a balance by weight of copolymerized ethylene monomer, based on the weight of the ethylene-vinyl acetate copolymer containing epoxy groups.

9. The vulcanizable composition according to claim 1 , wherein:

the at least one ethylene-vinyl acetate copolymer containing epoxy groups (a) comprises: at least 50% by weight of copolymerized vinyl acetate monomer, less than 10% by weight of copolymerized monomer which contains epoxy groups, and a balance by weight of copolymerized ethylene monomer, based on the weight of the ethylene-vinyl acetate copolymer containing epoxy groups; and

the at least one carboxylated nitrile rubber (b) comprises 2-10 parts by weight of the monomers containing carboxyl groups based on 100 parts by weight of the nitrile rubber which derives from acrylonitrile and the conjugated diene monomers.

10. The vulcanizable composition according to claim 9 , wherein:

the ratio by weight of (a) to (b) is 1:1; and

the at least one carboxylated nitrile rubber (b) is fully or partly hydrogenated.

11. The vulcanizable composition according to claim 9 , wherein the ratio by weight of (a) to (b) is 1:1.

12. The vulcanizable rubber composition according to claim 1 , wherein the at least one ethylene-vinyl acetate copolymer containing epoxy groups (a) comprises: 55.3% by weight of copolymerized vinyl acetate monomer, 6.7% by weight of copolymerized monomer which contains epoxy groups, and 38.0% by weight of copolymerized ethylene monomer, based on the weight of the ethylene-vinyl acetate copolymer containing epoxy groups.

13. The vulcanizable composition according to claim 1 , wherein the composition consists of the at least one ethylene-vinyl acetate copolymer (a) and the at least one carboxylated nitrile rubber (b).

14. A process for producing the vulcanizable composition according to claim 1 , the process comprising mixing the at least one ethylene-vinyl acetate copolymer containing epoxy groups (a) with the at least one carboxylated nitrile rubber (b).

15. A process for producing vulcanizates based on ethylene-vinyl acetate copolymers containing epoxy groups, the process comprising cross-linking the vulcanizable composition according to claim 1 with increasing temperature of 20 to 250° C.

16. The process according to claim 15 , wherein the temperature range is 100 to 210° C.

17. Vulcanizates obtained by the process according to claim 15 .