Silicone composition and electrically conductive silicone adhesive formed therefrom

Abstract

A silicone composition, comprising (A) 10 to 50 parts by weight of a polydiorganosiloxane having the formula R SiO(R SiO) SiR wherein each R is independently a monovalent aliphatic hydrocarbon group or a monovalent halogenated aliphatic hydrocarbon group, n has a value such that the polydiorganosiloxane has a viscosity from 0.1 to 200 Pa·s at 25° C., and the polydiorganosiloxane contains an average of at least two alkenyl groups per molecule; (B) 50 to 90 parts by weight of an organopolysiloxane resin consisting essentially of R SiO siloxane units and SiO siloxane units wherein each R is independently alkyl or alkenyl, the mole ratio of R SiO units to SiO units is from 0.65 to 1.9, the resin contains an average of from about 3 to 30 mole percent of alkenyl groups, and the total amount of components (A) and (B) is 100 parts by weight; (C) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule in an amount sufficient to cure the composition; (D) an electrically conductive filler in an amount sufficient to impart electrical conductivity to the composition; and (E) a catalytic amount of a hydrosilylation catalyst. An electrically conductive silicone adhesive comprising a reaction product of the above-described composition and a multi-part silicone composition comprising components (A) through (E) in two or more parts, provided neither component (A) nor component (B) are present with components (C) and (E) in the same part.