Thermally conductive silicon oxide composition and its manufacturing method

Abstract

The present invention is a thermally conductive silica composition comprising: 100 parts by mass of (A) a silanized reactant; 0.1 parts by mass and less than 5 parts by mass of (B) a monoterminated trialkoxy organopolysiloxane represented by general formula (2); 50 to 600 parts by mass of (C) a monoterminated monoalkoxy organopolysiloxane represented by general formula (3); 2001 to 20000 parts by mass of (D) a specific thermally conductive filler; wherein the aforementioned component (A) is a silanized reactant of the following components (E) and (F) in the presence of (G) a platinum metal catalyst and (H) a reaction controller: (E) a specific organopolysiloxane represented by general formula (1); (F) a specific polyorganohydrosiloxane having at least 3 hydrogen atoms bonded to silicon atoms in one molecule. This provides a thermally conductive silicon oxide composition that combines high thermal conductivity with resistance to cracking / porosity during high-temperature aging after moisture absorption.