Patent ID: 7247681

Claim:
A method for preparing a copolymer, comprising: (a) copolymerizing a conjugated diene monomer and a vinyl aromatic monomer in the presence of an organolithium catalyst in a hydrocarbon solvent and a Lewis base to obtain a living polymer; (b) coupling the living polymer with a multi-reactive polysiloxane represented by the following formula 1; and (c) subsequently modifying the uncoupled active ends of the living polymer with a compound represented by the following formula 2 or 3: (X) a (R) b Y—[CH 2 ] c —Si(R 1 )(R 2 )—[O—Si(R 1 )(R 2 )] d —[CH 2 ] c —Y(X) u (R) b Formula 1 wherein X is a halogen atom; Y is Si or C; R is a lower alkyl group having less than 20 carbon atoms; R 1 is a hydrogen atom, a halogen-substituted alkyl group, a halogen-substituted silane group, or the same as R; R 2 is halogen atom, or the same as R 1 ; a is from 1 to 3; b is (3-a), wherein a+b=3; c is from 1 to 1000; and d is from 1 to 50000, (R 2 3 NBz) 2 CO Formula 2 wherein R 3 is a lower alkyl group having less than 20 carbon atoms; and Bz is a benzene ring, wherein R 4 is a lower alkyl group having less than 20 carbon atoms.