| 摘要 |
PROBLEM TO BE SOLVED: To develop a heat-shrinkable polyester film which is good at shrinkability and causes no cracks by impact after the warming. SOLUTION: The resin composition for heat-shrinkable films and the film thereof contains 10-70 wt.% of (A) a polyester resin having the main repeating unit of a butylenes terephthalate unit and containing 1-30 wt.% of a polyoxytetramethylene glycol and also containing 3-30 mole % of an aromatic dicarboxylic acid component except terephthalic acid; and 30-90 wt.% of (B) a polyester resin having the main repeating unit of an ethylene terephthalate unit and containing at least one kind of a compound from the group consisting of isophthalic acid, cyclohexane dimethanol and neopentyl glycol in the sum total of 10-50 mole % (isophthalic acid is of mole % in the all acidic components, and cyclohexane dimethanol and neopentyl glycol are of mole % in the all glycolic components) and also having such a glass transition temperature of 50-10 deg.C, for this resin (B) subjected to the heat treatment for 5 minutes at 280 deg.C in nitrogen and to a rapid cooling, as measured by a differential scanning calorimeter at a programming rate of 10 deg.C/minute. |
