Semi-conductive rubber composition and vulcanizate thereof
View Patent ↗The present invention provides a rubber composition, which realizes low hardness and low compression set while maintaining semi-conductivity, and a vulcanizate thereof. Also the rubber composition can be obtained by blending an epichlorohydrin-based rubber having satisfactory semi-conductivity and an acrylonitrile-butadiene-based rubber as a reactive plasticizer, and also blending zinc oxide, a thiuram-based compound and a quinoxaline-based compound.
1. A rubber composition for a semi-conductive vulcanization, comprising, based on 100 parts by weight of a blend rubber comprising
(a) 50 to 90% by weight of an epichlorohydrin-based rubber and
(b) 10 to 50% by weight of a liquid acrylonitrile-butadiene-based rubber,
(c) 0.1 to 5 parts by weight of a thiuram-based compound,
(d) 1 to 10 parts by weight of zinc oxide and
(e) 0.1 to 5 parts by weight of a quinoxaline-based compound.
2. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein the epichlorohydrin-based rubber (a) is an epichlorohydrin-ethylene oxide-allyl glycidyl ether ternary copolymer.
3. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein a number average molecular weight of the acrylonitrile-butadiene-based rubber (b) is from 1,000 to 20,000.
4. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein the thiuram-based compound (c) is a thiuram sulfide-based compound.
5. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein the thiuram-based compound (c) is dipentamethylenethiuram tetrasulfide.
6. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein the quinoxaline-based compound (e) is a 2,3-dimercaptoquinoxaline derivative.
7. The rubber composition for a semi-conductive vulcanization according to claim 1 wherein the quinoxaline-based compound (e) is 6-methylquinoxaline-2,3-dithiocarbonate.
8. A semi-conductive vulcanized rubber material obtained by vulcanizing the rubber composition for a semi-conductive vulcanization according claim 1 .
9. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein a weight fraction of the epichlorohydrin-based rubber (a) is 60 to 80% and a weight fraction of the liquid acrylonitrile-butadiene-based rubber 20 to 40%.
10. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein a weight fraction of the epichlorohydrin-based rubber (a) is 80 to 90% and a weight fraction of the liquid acrylonitrile-butadiene-based rubber 10 to 20%.
11. The rubber composition for a semi-conductive vulcanization according to claim 1 , wherein the epichlorohydrin-based rubber is an epichlorohydrin-ethylene oxide-allyl glycidyl ether ternary copolymer, the copolymerization ratio of which is from 55 mol % to 80 mol %.