Diene rubber composition and tire using it in tread

摘要

A diene rubber composition comprising as a main rubber component an elastomeric polymer having a glass transition temperature of not less than -50 DEG C. selected from the group consisting of a butadiene homopolymer and a copolymer of butadiene and an aromatic vinyl compound, said elastomeric polymer being one prepared by a solution polymerization method and not less than 40% by weight to less than 65% by weight of the polymer chains thereof being branched polymer chains formed by coupling the polymer molecules with each other with a trifunctional or tetrafunctional coupling agent. The composition has excellent rolling resistance characteristic, wet grip characteristic, processability, tear strength and tackiness, and is suitable particularly for use in the tread portion of tires.