| 摘要 |
PROBLEM TO BE SOLVED: To obtain a heat-shrinkable polyester film extremely reduced in the occurrence of wrinkles, shrinkage irregularity and strain after shrinkage and excellent in the breakage resistance against an impact. SOLUTION: A stretched film composed of polyester wherein a terephthalic acid component among dicarboxylic acid components is 70mol% or more and an ethylene glycol component among diol components is 70mol% is characterized by that the max. value (σmax) of shrinkage stress in a main shrinkage direction at 90 deg.C is 0.5-1.2kg/mm<2> and a heat shrinkage factor in the main shrinkage direction in hot water is 40% or less at 75 deg.C and 50% or more at 95 deg.C. |
