Patent ID: 8158716

Claim:
A method for preparing an organopolysiloxane, comprising the steps of: (A) reacting (a) at least one organosiloxane free of a hydrolyzable group in a molecule with (b) an organosilane containing at least one hydrolyzable group in a molecule, said organosiloxane (a) being a cyclic organosiloxane of the general formula (1): (R 1 R 2 SiO) m (1) or a chain-like organosiloxane of the general formula (2): R 3 R 4 R 5 SiO—(R 6 R 7 SiO) n —SiR 8 R 9 R 10 (2) wherein R 1 to R 10 are each independently hydrogen or an optionally substituted monovalent hydrocarbon group of 1 to 10 carbon atoms, m is an integer of at least 3, and n is an integer inclusive of 0, said organosilane (b) being a silane compound having at least one alkoxysilyl group in a molecule, represented by the general formula (3): R 11 R 12 R 13 R 14 Si (3) wherein R 11 is an alkoxy group of 1 to 10 carbon atoms, R 12 , R 13 and R 14 are each independently hydrogen, hydroxyl, an optionally substituted monovalent hydrocarbon group of 1 to 10 carbon atoms, or an alkoxy group of 1 to 10 carbon atoms, or a partial hydrolytic condensate thereof, at least one of component (b) containing a hydrosilyl group, in the presence of a superstrong acid catalyst and in the substantial absence of water to form a hydrolyzable group-containing organohydrogenpolysiloxane in a reaction solution; (B) adding an inorganic basic neutralizing agent consisting of a crystalline layer compound containing at least one element selected from Mg and Al, (C) removing the neutralized form of the superstrong acid catalyst to prepare a hydrolyzable group-containing organohydrogenpolysiloxane, and (D) addition reacting the hydrolyzable group-containing organohydrogenpolysiloxane and at least one unsaturated bond-containing organic compound having the general formula (4): CH 2 ═CH—R 15 (4) wherein R 15 is hydrogen or an organic group.