Abstract: A thermally-conductive two-part addition-curable silicone composition including a first liquid and a second liquid and a method of producing the same. The first liquid includes a heat-treated mixture including an organopolysiloxane having two or more alkenyl groups and aluminum oxide having Na+ ion content equal to or lower than 100 ppm, a platinum-group metal catalyst, and an ion-trapping agent of a cation-exchange type and/or a cation-and-anion-exchange type. The second liquid includes a heat-treated mixture including an organopolysiloxane having two or more alkenyl groups, an organohydrogenpolysiloxane having three or more SiH groups, aluminum oxide having Na+ ion content equal to or lower than 100 ppm, and an organohydrogenpolysiloxane having two SiH groups.

Abstract: A high thermal conductive silicone composition including: (A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and a kinematic viscosity at 25 C of 100 to 100,000 mm2/s; (B) an aluminum powder having an average particle size of 50 ?m or more; (C) a thermal conductive filler having an average particle size of 0.1 to less than 50 ?m; (D) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom (Si—H groups) in one molecule; (E) a hydrolyzable organopolysiloxane represented by the following general formula (1); and (F) a platinum group metal catalyst having an effective amount. The high thermal conductive silicone composition can conform to the warpage of a substrate due to an increased material thickness and can maintain heat dissipation performance due to a high thermal conductivity.

Abstract: This thermally conductive addition curing silicone composition contains: a heated mixture of an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, an organohydrogen polysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule, and aluminum oxide particles having an Na+ ion level of 50 ppm or less when an aluminum oxide powder is heat extracted by pure water for 24 hours at 60° C. and the resultant water layer is measured by ion chromatography, the aluminum oxide particles having been surface-treated by the organohydrogen polysiloxane; an organohydrogen polysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule; and a platinum group metal catalyst. Said composition can be applied to the inside of a module including electrical/electronic components and a circuit board on which these compounded are mounted, and can exhibit exceptional post-curing stress relaxation properties and thermal conductivity.