Rubber composition and method for making
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMasaharu Takahashi, Tsutomu Nakamura, Kazuo Numata
Life of this patent
Estimating the term…
Abstract
A conductive rubber composition is prepared by blending (A) a rubber composition including natural and/or synthetic rubber and conductive carbon black, with (B) a silicone rubber composition including an organopolysiloxane having the average composition formula: R.sub.n SiO.sub.(4-n)/2 wherein R is a hydrocarbon group and n is a positive number of from 1.95 to 2.05. This rubber composition and cured products thereof have stable electric resistivity in the semiconductive range and are thus suitable as rubber roll members in business machines.
Claims11
A rubber composition for preparing a rubber article having a variation of electric resistivity of about one order of magnitude in the range of from 10.sup.3 to 10.sup.10 .OMEGA..multidot.cm comprising in admixture, two separate phases (A) and (B) macroscopically dispersed in one another wherein,
- phase (A) is a rubber composition comprising natural rubber, synthetic rubber, or mixtures thereof, and conductive carbon black, said synthetic rubber being ethylene-propylene rubber, ethylene-propylene-diene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, acrylic rubber, silicone-modified EPDM rubber, silicone-modified acrylic rubber, ethylene-acrylate rubber, ethylene-vinyl acetate rubber, urethane rubber, polysulfide rubber, chloro-sulfonated polyethylene rubber, chlorinated polyethylene rubber, fluorinated rubber, epichlorohydrin rubber, or mixtures thereof, and
- phase (B) is a silicone rubber composition comprising an organopolysiloxane having the average composition formula (1):
- R.sub.n SiO.sub.(4-n)/2 ( 1)
- wherein R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n is a positive number of from 1.95 to 2.05, and containing essentially no carbon black,
- wherein rubber compositions (A) and (B) are combined in a weight ratio of 5:95 to 95:5.
A method for preparing a rubber composition comprising combining
- (A) a rubber composition comprising natural rubber, synthetic rubber, or mixtures thereof and conductive carbon black, said synthetic rubber being ethylene-propylene rubber, ethylene-propylene-diene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, acrylic rubber, silicone-modified EPDM rubber, silicone-modified acrylic rubber, ethylene-acrylate rubber, ethylene-vinyl acetate rubber, urethane rubber, polysulfide rubber, chloro-sulfonated polyethylene rubber, chlorinated polyethylene rubber, fluorinated rubber, epichlorohydrin rubber, or mixtures thereof, with
- (B) a silicone rubber composition comprising an organopolysiloxane having the average composition formula (1):
- R.sub.n SiO.sub.(4-n)/2 ( 1)
- wherein R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n is a positive number of from 1.95 to 2.05, and containing no carbon black, wherein rubber compositions (A) and (B) are combined in a weight ratio of 5:95 to 95:5 to form a two-phase mixture of rubber compositions (A) and (B) macroscopically dispersed in one another.
Dependencies are inferred from the claim text.