| 摘要 |
PURPOSE:To obtain a block copolymer excellent in transparency, rigidity, impact resistance, low-temperature stretchability and spontaneous-shrinkage resistance by forming a specified block copolymer comprising blocks of a vinylaromatic hydrocarbon polymer and blocks of a polymer comprising a vinylaromatic hydrocarbon and a conjugated diene. CONSTITUTION:The title copolymer comprises blocks of a vinylaromatic hydrocarbon polymer and blocks B1 and B2 of a polymer comprising a vinylaromatic hydrocarbon and a conjugated diene, wherein at least one of the terminals is a vinylaromatic hydrocarbon polymer block, and the following relationship holds: 1.1<=M2/M1<=5 (wherein M2 is the ratio of the weight of the conjugated diene of the polymer block B2 to that of the vinylaromatic hydrocarbon of polymer block B2; and M1 is the ratio fo the weight of the conjugated diene of the polymer block B1 to that of the vinylaromatic hydrocarbon of polymer block B1). |
