Patent ID: 8759456

Claim:
An addition reaction-curable organopolysilmethylenesiloxane copolymer composition comprising: (A) an organopolysilmethylenesiloxane copolymer in an amount of 1 to 100% by weight, which is represented by formula (a) shown below: wherein R 1 is independently selected from an unsubstituted or substituted monovalent hydrocarbon group with a carbon number of 1 to 10, alkoxyl group, hydroxyl group, halogen atom, (R 01 ) 3 SiCH 2 —, and (R 01 ) 3 SiO— in which R 01 is independently selected from an unsubstituted or substituted monovalent hydrocarbon group with a carbon number of 1 to 10, and m is 1 to 100, n is 3 to 1,000, and o is 1 to 20, the organopolysilmethylenesiloxane copolymer having in one molecule at least two alkenyl groups bonding to silicon atoms; (B) an organopolysiloxane in an amount of 0 to 99% by weight, which is represented by the average compositional formula (b) shown below: R 2 a SiO (4-a)/2 (b) wherein R 2 is independently selected from an unsubstituted or substituted monovalent hydrocarbon group with a carbon number of 1 to 10, alkoxyl group, hydroxyl group, and halogen atom, and a is a number satisfying 0.7≦a≦3.0, the organopolysiloxane having in one molecule at least two alkenyl groups bonding to silicon atoms; the total amount of components (A) and (B) being 100% by weight, (C) an organohydrogenpolysilmethylenesiloxane and/or organohydrogenpolysiloxane as a crosslinking agent which has in one molecule at least two hydrogen atoms bonding to silicon atoms, said crosslinking agent being in such an amount that the hydrogen atoms bonding to silicon atoms in this component (C) accounts for 0.1 to 5.0 mol per mol of all alkenyl groups in the addition reaction-curable organopolysilmethylenesiloxane copolymer composition; and (D) a platinum group metal-based catalyst in an effective amount.