Patent ID: 7026387

Claim:
A process for the preparation of a rubber composition comprising a reinforcing white filler, wherein the rubber composition comprises a diene block copolymer which is intended to interact with said reinforcing white filler, said diene block copolymer comprising on at least one end thereof a polysiloxane block which ends in a trialkylsilyl group, said polysiloxane block corresponding to the formula: [—(SiR 1 R 2 O)—] x -SiR 3 R 4 R 5 , in which R 1 , R 2 , R 3 , R 4 and R 5 represent alkyl groups having from 1 to 20 carbon atoms, and in which x is a natural integer other than zero, wherein the process comprises (a) reacting a living diene polymer with a functionalized polysiloxane comprising at one of its chain ends a halo-organosilane function and, at its other chain end, a trialkylsilyl group, to produce said diene block copolymer comprising said polysiloxane block which ends in a trialkylsilyl group, and (b) mixing, by thermomechanical working, said diene block copolymer with silica, and with conventional additives for obtaining a vulcanizable rubber composition.