Silicone composition, method for the preparation thereof, and silicone elastomer

摘要

A silicone composition comprising (A) 100 parts by weight of a polydiorganosiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule; (B) 75 to 150 parts by weight of an organopolysiloxane resin having a number-average molecular weight of from 2,000 to 5,000 and consisting essentially of R32R4 SiO+E,fra 1/2+EE units and SiO4/2 units wherein each R3 is independently selected from the group consisting of monovalent hydrocarbon and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, R4 is selected from the group consisting of R3 and alkenyl, the mole ratio of R32R4 SiO+E,fra 1/2+EE units to SiO4/2 units is from 0.6:1 to 1.1:1, and the resin contains an average of from 2.5 to 7.5 mole percent of alkenyl groups; (C) an organohydrogenpolysiloxane having an average of at least three silicon-bonded hydrogen atoms per molecule in an amount sufficient to provide from one to three silicon-bonded hydrogen atoms per alkenyl group in components (A) and (B) combined; (D) an adhesion promoter in an amount sufficient to effect adhesion of the composition to a substrate; and (E) a hydrosilylation catalyst in an amount sufficient to cure the composition.