Curable Silicone Composition, Cured Product Thereof, 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 (R12SiO2/2)b(R13SiO1/2)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.

主权项

1. 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(R12SiO2/2)b(R13SiO1/2)c(SiO4/2)d(XO1/2)e wherein, R1 each independently represent an alkyl group having from 1 to 12 carbon atoms, an alkenyl group having from 2 to 12 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, or a group in which some or all of 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, in an amount such that the mass ratio of component (A) to component (B) is from 1/99 to 99/1; (C) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule, in an amount such that the amount of silicon-bonded hydrogen atoms in this component is from 0.1 to 10 moles per 1 mol of the total alkenyl groups in components (A) and (B); (D) a cerium-containing organopolysiloxane, in an amount such that the amount of cerium atoms in component (D) is from 20 to 2,000 ppm in terms of mass units with respect to the total mass of the composition; and (E) a catalytic quantity of a hydrosilylation reaction catalyst.