Curable silicone rubber composition and method for preparing silicone rubber

Claim 1

A curable silicone rubber composition comprising, (A) 100 parts by weight of an organopolysiloxane containing 0.001 to 1% by weight of a vinyl group and having a viscosity of 1,000 to 1,000,000 poise at 25° C., (B) 5 to 50 parts by weight of an organopolysiloxane containing 0.1 to 10% by weight of a vinyl group and having a viscosity of 0.05 to 100 poise at 25° C., (c) 5 to 50 parts by weight of an organopolysiloxane copolymer mainly comprising a triorganosiloxy unit (M) of the general formula (1): R.sup.1.sub.3 SiO.sub.1/2 ( 1) wherein R 1 is selected from the group consisting of a vinyl group, a phenyl group, an alkyl group having 1 to 8 carbon atoms, and a fluoroalkyl group having 3 to 10 carbon atoms and a SiO 2 unit (Q) in a molar ratio (M/Q) between 0.6 and 1.2 and containing 0.1 to 10% by weight of a vinyl group, (D) an organohydrogensiloxane containing at least three hydrogen atoms each directly attached to a silicon atom in a molecule in an amount to provide 0.5 to 10 mol of the silicon atom-attached hydrogen atom per mol of the vinyl groups in components (A), (B) and (C) combined, (E) a catalytic amount of a platinum catalyst, and (F) 10 to 150 parts by weight of finely divided silica having a specific surface area of at least 50 m 2 /g.