| 摘要 |
PURPOSE:To obtain a uniaxially oriented film with transparency, excellent low temperature stretching and low temperature contracting properties, and having good mechanical strength by employing block polymer having a specific range of molecular weight and molecular weight distribution as polymer consisting mainly of vinyl aromatic hydrocarbon. CONSTITUTION:In a uniaxially oriented film, sheet or tube suitable for use in contraction wrapping, resin comprising at least polymeric block consisting mainly of one vinyl aromatic hydrocarbon, and polymeric block consisting mainly of one conjugate diene is employed. In this instance, block copolymer is employed wherein a number average molecular weight of the vinyl aromatic hydrocarbon is 10000-70000, and the ratio between the weight average molecular weight of the vinyl aromatic hydrocarbon block and the number average molecular weight is in the range of 1.25-2.5, and the weight ratio between the vinyl aromatic hydrocarbon and the conjugate diene is 60:40--95:5, and which is then subjected to uniaxial orientation, to thereby obtain a uniaxially oriented film or the like which has a thermal contraction of 15% or more at 80 deg.C in the stretching direction. |
