Curable organopolysiloxane compositions

Claim 1

A curable organopolysiloxane composition comprising, in admixture, (A) an organopolysiloxane having at least two alkenyl groups in a molecule and a viscosity of 100 to 200,000 centistokes at 25° C., (B) an organopolysiloxane having the general compositional formula (I): (A).sub.a (D).sub.b (E).sub.c (G).sub.d (J).sub.e (L).sub.f (M).sub.g (I) wherein A=[(R 1 O) h R 2 3-h Si(CH 2 ) n ] i R 2 3-i SiO 1/2 , D=[CH 2 ═CH(CH 2 ) n-2 ] i R 2 3-i SiO 1/2 , E=(R 1 O) 3 SiO 1/2 , G 32 R 1 3 SiO 1/2 , J=HO 178 , L=R 1 O 178 , M=SiO 4/2 , R 1 is a monovalent saturated hydrocarbon group having 1 to 10 carbon atoms, R 2 is a monovalent saturated hydrocarbon group having 1 to 10 carbon atoms or aryl group, letters a, b, c, d, e, f, and g are numbers meeting a>0, b>0, c≧0, d≧0, e≧0, f≧0, g>0, a+b+c+d+e+f+g=1, and 0.4≦(a+b+c+d+e+f)/g≦4, h and i each are an integer of from 1 to 3, and n is an integer of at least 2, (C) an organohydrogenpolysiloxane having at least two hydrogen atoms attached to silicon atoms in a molecule, and (D) an addition reaction catalyst selected from the group consisting of platinum and a platinum compound.