| 摘要 |
PROBLEM TO BE SOLVED: To obtain a heat-shrinkable polystyrene tube excellent in impact resistance and, particularly, cold heat impact resistance. SOLUTION: This tube is prepared by orienting a tube made of a mixed polymer prepared by a method wherein butadiene rubber and/or a graft polymer prepared by polymerizing methacrylate ester and aromatic vinyl on particles of a copolymer of butadiene in a superior amount and a monomer in an inferior amount having copolymerization power is blended in a styrene copolymer constituted of a styrene monomer and (meth)acrylic ester, at the rate of 3-50 wt.% of the whole mixture as a basis, so that the shrinkage factors of the tube in hot water of 100 deg.C for 30 seconds be 40% or below in the length direction and 40% or above in the radial direction. The tube thus prepared is excellent in impact resistance and, particularly, cold heat impact resistance and useful for a coating of a negative pole can of a lithium ion secondary battery or others. |
