Patent ID: 8373286

Claim:
A curable organopolysiloxane composition that comprises (A) a diorganopolysiloxane that has at least 2 alkenyl groups in one molecule wherein at least 70 mole % of all the siloxane units in the diorganopolysiloxane are methylphenylsiloxane units and the total content of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane is no more than 5 weight %, (B) an organopolysiloxane that has at least 2 silicon-bonded hydrogen atoms in one molecule wherein at least 15 mole % of the silicon-bonded organic groups in the organopolysiloxane are phenyl groups in a quantity that provides 10 to 500% for the number of moles of silicon-bonded hydrogen atoms in component (B) relative to the total number of moles of alkenyl groups in component (A), and (C) a hydrosilylation reaction catalyst in a quantity sufficient to cure the composition.