| CPC C09K 5/08 (2013.01) [H01L 23/3737 (2013.01)] | 12 Claims |
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1. A heat-conductive silicone composition comprising:
(A) 100 parts by weight of an organopolysiloxane of general formula (1) below
 (wherein each R is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, multiple occurrences of R may be the same or may be different, and n is an integer of 10 or more);
(B) from 150 to 600 parts by weight of an organopolysiloxane of general formula (2) below having at least one hydrolyzable silyl group per molecule
 (wherein each R1 is independently a substituted or unsubstituted monovalent hydrocarbon group, X1 and X3 are each independently a group represented by R1 or —R2—SiR3g(OR4)3-g, and X2 is a group represented by —R2—SiR3g(OR4)3-g, there being at least one —R2—SiR3g(OR4)3-g moiety on the molecule; R2 is an oxygen atom or an alkylene group of 1 to 4 carbon atoms, each R3 is independently a substituted or unsubstituted monovalent hydrocarbon group which does not contain an aliphatic unsaturated bond, each R4 is independently an alkyl group of 1 to 4 carbon atoms or an alkoxyalkyl, alkenyl or acyl group of 2 to 4 carbon atoms, and g is an integer from 0 to 2; the subscripts a and b respectively satisfy the conditions 1≤a≤1,000 and 0≤b≤1,000, with the proviso that if X1 and X3 are both R1, b satisfies the condition 1≤b≤1,000; and recurring units may each be randomly bonded);
(C) from 0.1 to 100 parts by weight of a crosslinking agent which is a hydrolyzable organosilane compound having one unsubstituted monovalent hydrocarbon group selected from the group consisting of alkyl groups of 1 to 4 carbon atoms, alkenyl groups of 2 to 4 carbon atoms and aryl groups of 6 to 8 carbon atoms and three hydrolyzable groups per molecule and/or a partial hydrolytic condensation product thereof;
(D) from 1,500 to 6,500 parts by weight of zinc oxide particles which have a mean particle diameter of at least 0.1 μm but not more than 2 μm and contain a proportion of coarse product having a particle diameter of 10 μm or more in laser diffraction particle size distribution that is not more than 1 vol % of component (D) overall; and
(E) from 0.01 to 30 parts by weight of an adhesion promoter exclusive of component (C), wherein the composition has a content of component (D) that is from 45 to 70 vol % of the overall composition and a thermal conductivity at 25° C. as determined by the hot disk method of at least 1.3 W/mK, and is compressible to a thickness of 10 μm or less.
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