CURABLE SILICONE COMPOSITION, CURED PRODUCT THREREOF, AND OPTICAL SEMICONDUCTOR DEVICE

摘要

This invention relates to a curable silicone composition comprising: (A) a straight-chain organopolysiloxane having at least two alkenyl groups in a molecule; (B) an organopolysiloxane represented by the following average unit formula: (R1SiO3/2)a (R1 2SiO2/2)b (R1 3SiO1/2)c (SiO4/2)d (XO1/2)e wherein, R1 each independently represent an alkyl group having from 1 to 12 carbons, an alkenyl group having from 2 to 12 carbons, an aryl group having from 6 to 20 carbons, an aralkyl group having from 7 to 20 carbons, or a group in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, with the proviso that at least two R1 in a molecule are the alkenyl groups, X is a hydrogen atom or an alkyl group, a is a number from 0 to 0.3, b is 0 or a positive number, c is a positive number, d is a positive number, e is a number from 0 to 0.4, a + b + c + d = 1, c/d is a number from 0 to 10, and b/d is a number from 0 to 0.5; (C) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule; (D) a cerium-containing organopolysiloxane; and (E) a hydrosilylation reaction catalyst. The curable silicone composition does not develop cracks due to thermal aging and can form a cured product having little yellow discoloration.