HYDROGENATED BLOCK COPOLYMER OF STYRENE BASED AROMATIC HYDROCARBON AND CONJUGATE DIENE, ITS COMPOSITION, AND OPTICAL MOLDING MATERIAL

摘要

PROBLEM TO BE SOLVED: To obtain a hydrogenated styrene based polymer in which moldability is compatible with the mechanical property, and a composition containing the same. SOLUTION: The copolymer is obtained by the hydrogenation of unsaturated groups in a block copolymer of a styrene based aromatic hydrocarbon and a conjugate diene. In the copolymer, the chain ends are hydrogenated conjugate diene polymer blocks, the weight ratio of hydrogenated styrene based aromatic hydrocarbon polymer block/hydrogenated conjugate diene polymer block is 70/30-99/1, the hydrogenated rate of unsaturated groups in the copolymer is not less than 90 mol%, and the hydrogenated conjugate diene polymer block is crystalline. A composition containing the copolymer and the use of the composition are also provided.