Patent ID: 8022129

Claim:
A conjugated diolefin copolymer rubber comprising a conjugated diolefin and an aromatic vinyl compound, the conjugated diolefin copolymer rubber (1) having a primary amino group and an alkoxysilyl group bonded to the copolymer chain, and (2) containing a polymerization unit of the aromatic vinyl compound in an amount of 5 to 60 wt %, wherein (3) the aromatic vinyl compound is distributed densely in one terminal of the copolymer chain and scarcely distributed in the other terminal, and the conjugated diolefin copolymer rubber (4) has a temperature difference (ΔTg) between the inflection points in the glass transition temperature region of the endothermic curve determined by a differential scanning calorimeter (DSC) of 25° C. or more.