A modified block copolymer.

摘要

A modified block copolymer comprising a radial base block copolymer of at least two monovinyl substituted aromatic hydrocarbon polymer blocks (A) and at least one olefin compound polymer block (B) composed mainly of a conjugated diene compound which polymer block (B) has its conjugated diene compound moiety hydrogenated to have an ethylenic unsaturation degree not exceeding 20 %, said radial base block copolymer having a monovinyl substituted aromatic hydrocarbon content of 5 to 95 % by weight, said conjugated diene compound moiety of said polymer block (B) having a vinyl content of 25 to 65 % in terms of the vinyl content prior to the hydrogenation of said conjugated diene compound moiety; and at least one molecular unit grafted to said radial base block copolymer, said molecular unit containing at least one member selected from a dicarboxylic acid group and groups derived therefrom.