Patent ID: 8080614

Claim:
A curable organopolysiloxane composition comprising at least the following components: 100 parts by mass of an organopolysiloxane (A) represented by the following general formula: R 1 3 SiO(R 1 2 SiO) m SiR 1 3 where R 1 may be the same or different substituted or unsubstituted monovalent hydrocarbon groups; wherein, in one molecule, at least two R 1 s are alkenyl groups; at least one of the R 1 s is an aryl group; and “m” is an integer from 0 to 100; 10 to 150 parts by mass of an organopolysiloxane (B) represented by the following average unit formula: (R 2 SiO 3/2 ) a (R 2 2 SiO 2/2 ) b (R 2 3 SiO 1/2 ) c where R 2 may be the same or different substituted or unsubstituted monovalent hydrocarbon groups; wherein, in one molecule, 0.5 or more mole % of R 2 s are alkenyl groups; 25 mole % or more of R 2 s aryl groups; and “a”, “b”, and “c” are numbers that satisfy the following conditions: 0.30≦a≦0.60; 0.30≦b≦0.55; (a+b+c)=1, and 0.10≦[c/(a+b)]≦0.30; an organopolysiloxane (C) having in one molecule on average at least two silicon-bonded aryl groups and on average at least two silicon-bonded hydrogen atoms wherein the silicon-bonded hydrogen atoms component (C) are present in an amount of 0.1 to 10 moles per one mole of the total number of alkenyl groups contained in component (A) and component (B); and a hydrosilylation-reaction catalyst (D) present in an amount sufficient for curing the present composition.