High vinyl polybutadiene or styrene-butadiene copolymer

Abstract

High vinyl polybutadiene or styrene-butadiene copolymer obtained by polymerizing 1,3-butadiene alone or with styrene in a hydrocarbon solvent using an organolithium compound as an initiator and coupling the resulting polymer, characterized in that (1) the polybutadiene or styrene-butadiene copolymer comprises at least 20% by weight of a polymer having in its molecular chain a linkage between butadienyl and at least one metal selected from the group consisting of silicon, germanium, tin and lead, (2) the styrene content of said copolymer is 40% by weight or less, and (3) the polybutadiene or the butadiene portion of the styrene-butadiene copolymer has a vinyl content of 50 to 95%. Said polybutadiene or styrene-butadiene copolymer has low rolling resistance, high wet skid resistance, highly improved fracture property and, an excellent processability.

Dependencies are inferred from the claim text.