Thermally softening and thermally conductive silicon oxide compositions and hardeners

Abstract

This invention relates to a thermally softening and conductive silicone composition comprising: (A) a phenyl-modified organopolysiloxane having two or more alkenyl groups in one molecule, a kinematic viscosity of 100–100,000 mm² / s at 25°C, and free of T-units; (B) an organohydrogen polysiloxane having at least two silanol groups at the ends of its molecular chains; (C) one or more organopolysiloxanes having hydrolyzable functional groups and alkoxysilane compounds represented by specific formulas; (D) one or more thermally conductive fillers selected from the group consisting of metals, metal oxides, metal hydroxides, and metal nitrides; and (E) a platinum group metal catalyst. This provides a thermally softening and conductive silicone composition and a cured product that does not contain thermoplastic silicone resins having T-units and exhibits excellent thermal softening properties. Furthermore, a hardened form of a thermally softening and thermally conductive silicon oxide composition is provided, which exhibits excellent reworkability.