Patent ID: 7649059

Claim:
An addition-curable organopolysiloxane resin composition comprising (A) 100 parts by weight of an organopolysiloxane resin that has the average compositional formula: R 1 a R 2 b (HO) c SiO (4-a-b-c)/2 (1) R 1 is C 2-10 alkenyl, R 2 is a group selected from unsubstituted or substituted monovalent hydrocarbyl, excluding alkenyl, and alkoxy wherein at least 30 mole % of R 2 is phenyl, and a, b, and c are positive numbers that satisfy the following: a+b+c is 1.0 to 2.0, a is at least 0.1, and c is at least 0.2 and that contains at least alkenyl, hydroxyl, and phenyl group directly bonded to silicon, (B) 20 to 100 parts by weight of an organohydrogenoligosiloxane or organohydrogenpolysiloxane that has the average compositional formula: H d R 3 e SiO (4-d-e)/2 (2) R 3 is a group selected from unsubstituted or substituted monovalent hydrocarbyl, excluding alkenyl, alkoxy, and hydroxyl group wherein at least 20 mole % of R 3 is phenyl, d is 0.35 to 0.65, and e is 0.90 to 1.70 and that contains at least phenyl group directly bonded to silicon, and (C) an addition reaction-curing catalyst in a catalytic quantity.