Addition-cured silicone composition and optoelectronic semiconductor device

Abstract

The present invention was made in view of the aforementioned problems, and its object is to provide an addition-curing silicone composition that imparts excellent mechanical properties to a cured material and has low viscosity and excellent workability; and to provide an optical semiconductor device comprising a cured material cured from the composition. An addition-curing silicone composition comprises: (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule; (B) an organohydrogen polysiloxane having two or more hydrogenated silyl groups in one molecule and not having alkoxy groups bonded to silicon atoms, wherein the amount is such that the molar ratio of the hydrogenated silyl groups to the alkenyl groups in component (A) is 0.4 to 4.0; and (C) a platinum group metal catalyst, wherein the amount is 0.1 ppm to 100 ppm relative to the total mass of components (A) and (B), converted to platinum group metal mass. The amount in ppm; (D) an inorganic filler comprising (D1) and (D2) and surface-treated with an organosilicone compound, comprising 25 parts by mass and 900 parts by mass relative to 100 parts by mass of component (A): (D1) an inorganic filler; (D2) an organosilicone compound having one or more hydrogenated silyl groups in one molecule and one or more alkoxy groups bonded to silicon atoms in one molecule; comprising 0.1 to 2 parts by mass relative to 100 parts by mass of component (D1).