| 摘要 |
PROBLEM TO BE SOLVED: To provide a block copolymer comprising hydrogenated diene residue units and having negative birefringence and excellent transparency, heat resistance, mechanical strength, and flexibility and to provide an optical film comprising the same. SOLUTION: The hydrogenated block copolymer is an A-B-A block copolymer obtained by the copolymerization of a vinylnaphthalene represented by formula (I) with a diene represented by formula (II), wherein the content of vinylnaphthalene residue units in the copolymer is 70 to 99 wt.%, the diene residue units are hydrogenated, and the number-average molecular weight is 40,000 to 300,000. The optical film comprises the same. In formula (I), R<SB>1</SB>is hydrogen or a 1 to 12C alkyl group. In formula (II), R<SB>2</SB>to R<SB>5</SB>are each independently hydrogen or a 1 to 6C alkyl group. COPYRIGHT: (C)2006,JPO&NCIPI |
