| 摘要 |
PURPOSE:To provide a thermally shrinking polyester film which has a large percentage of thermal shrinkage, does not generate shrinkage mottles after thermal shrinkage, and has good dimensional stability in various processes after thermal shrinkage. CONSTITUTION:A thermally shrinking polyester film is characterized by the shrinkage at 100 deg.C of 40% or more and its relaxation spectrum curve obtained by measuring the stress of thermal shrinkage which satisfies all the expressions (1)-(3); 300>=f (log tau1) >=10 [g/mm<2>/log (sec)] (1), 300>=f (logtau2)>=50 [g/mm<2>/log (sec)] (2), and 1X10<3>>=tau1>=2X10-1(sec) (3), where f (logtau) is a relaxation spectrum based on 100 deg.C and 10sec, tau1 is the relaxation time which gives a maximum value to f (logtau), and tau2 is 3X10<0>sec. |
