| 摘要 |
A branched conjugated diene-aromatic vinyl copolymer (C) being a random copolymer, wherein the aromatic vinyl bond content in the conjugated diene-aromatic vinyl copolymer (C) is from 30 to 38 mass%, the vinyl bond content in the total bond units of the conjugated diene is from 30 to 43 mol%, the weight average molecular weight (Mw-C) in terms of polystyrene obtained by gel permeation chromatography (GPC) of the conjugated diene-aromatic vinyl copolymer (C) is from 700,000 to 1,000,000, the ratio of the weight average molecular weight (Mw-C) to the number average molecular weight (Mn-C) ((Mw-C)/(Mn-C)) is from 1.7 to 3.0, and the Mooney viscosity (ML-C) and the Mooney relaxation ratio (MSR-C) measured at 120°C satisfy the relationship represented by formula (1): {214-(ML-C)}/300 = (MSR-C) = {260-(ML-C)}/300 (wherein 100 = (ML-C) = 140). |
