JP2003128861A5 - - Google Patents

Claims (6)

A copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene produced using an organolithium compound as an initiator, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene in the copolymer is 85/15 to 95/5, The block ratio of vinyl aromatic hydrocarbon incorporated in the polymer is 10 to 80% by weight, the number average molecular weight of vinyl aromatic hydrocarbon polymer block is 50,000 to 60,000, Vicat softening temperature Having a copolymer (I) in the range of 50 to 88 ° C., at least one plastic polymer segment A and at least one elastomeric polymer segment B, and comprising a vinyl aromatic hydrocarbon and a conjugated diene Is a block copolymer having a weight ratio of 65/35 to 82/18, and the block copolymer has at least one peak of dynamic viscoelasticity function tan δ at 70 to 125 ° C. A block copolymer (II) having a Vicat softening temperature in the range of 60 to 83 ° C., and the weight ratio of the copolymer (I) to the block copolymer (II) is A polymer composition which is 10/90 to 90/10. A copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene produced using an organolithium compound as an initiator, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene in the copolymer is 85/15 to 95/5, The block ratio of vinyl aromatic hydrocarbon incorporated in the polymer is 10 to 80% by weight, the number average molecular weight of vinyl aromatic hydrocarbon polymer block is 50,000 to 60,000, Vicat softening temperature Having a copolymer (I) in the range of 50 to 88 ° C., at least one plastic polymer segment A and at least one elastomeric polymer segment B, and comprising a vinyl aromatic hydrocarbon and a conjugated diene Is a block copolymer having a weight ratio of 65/35 to 82/18, and the block copolymer has at least one peak of dynamic viscoelasticity function tan δ at 70 to 125 ° C. Block copolymer (II) and a styrene-n-butyl acrylate copolymer (III) having a styrene content of 70 to 90% by weight and an n-butyl acrylate content of 30 to 10% by weight. The composition has a Vicat softening temperature in the range of 60 to 83 ° C., and the copolymer (I), the block copolymer (II), and the styrene-n-butyl acrylate copolymer (III) The weight ratio of the polymer composition is such that (I) is 10 to 80% by weight, (II) is 10 to 80% by weight, and (III) is 5 to 50% by weight, with the total amount being 100% by weight. object. A heat shrinkage obtained by stretching the polymer composition according to claim 1, wherein the heat shrinkage rate at 65 ° C. in the stretching direction is 10 to 60%, and the tensile elastic modulus in the stretching direction is 7000 to 30000 Kg / cm ^2. Sex film. In the copolymer (I), the block ratio of the vinyl aromatic hydrocarbon incorporated in the copolymer is 15 to 75% by weight, and the number average molecular weight of the vinyl aromatic hydrocarbon polymer block is 88,000. The polymer composition according to claim 1, wherein the polymer composition is ˜50,000 and the Vicat softening temperature is in the range of 55 to 85 ° C. 4. The melt flow index (MFR) measured at 200 ° C. under a load of 5 kg by the measurement method described in JIS-K-6870 is 0.1 to 50 g for the copolymer (I) and the block copolymer (II). The polymer composition according to claim 1, wherein the polymer composition is 1 to 10 g / 10 min for the polymer (III). The heat-shrinkable film according to claim 3, wherein the stretching temperature is 60 to 110 ° C and the stretching ratio is 1.5 to 8 times.