Patent ID: 7005469

Claim:
A modified rubber comprising a modified copolymer represented by the general formula (R-B) n -X obtained by modifying a copolymer having an (R-B) structure, wherein the modified rubber has a total bound vinylaromatic hydrocarbon content of from 5 to 60% by weight, a bound vinylaromatic hydrocarbon polymer block content of from 3 to 40% by weight, and a vinyl content in the conjugated diene moieties of 80% by mole or lower and the main-peak molecular weight of the molecules which have been coupled by a modifier is from 100,000 to 1,500,000 as determined by GPC, wherein, in the formulae, R represents a conjugated diene polymer or a vinylaromatic hydrocarbon/conjugated diene random copolymer having a bound vinylaromatic hydrocarbon content of 50% by weight or lower; B represents a vinylaromatic hydrocarbon/conjugated diene copolymer having a vinylaromatic hydrocarbon polymer block or represents a vinylaromatic hydrocarbon polymer block, the R/B weight ratio being in the range of from 30/70 to 97/3; n is an integer of 1 or larger; and X represents a modification residue of a compound having two or more epoxy groups per molecule.