Patent ID: 7527871

Claim:
A curable organopolysiloxane composition comprising; (A) a linear organopolysiloxane having at least two silicon bonded alkenyl groups and at least one silicon bonded aryl group per molecule, in which the content of the silicon bonded aryl groups relative to all the silicon bonded organic groups in component (A) is not less than 40 mol %, (B) a branched organopolysiloxane having at least one silicon bonded alkenyl group and at least one silicon bonded aryl group per molecule, and having siloxane units represented by the general formula: RSiO 3/2 , where R is a substituted or unsubstituted monovalent hydrocarbon group and where component (B) is present in an amount necessary for a weight ratio of from 1/99 to 99/1 relative to component (A), (C) a linear organopolysiloxane with both terminal ends of the molecular chain blocked by silicon bonded hydrogen atoms having at least one silicon bonded aryl group per molecule, where component (C) is present in an amount necessary to provide 1 to 200 parts by weight relative to 100 parts by weight of the total of component (A) and component (B), and (D) a hydrosilation reaction catalyst present in an amount necessary to promote the curing of the present composition.