| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a heat-shrinkable polyester film which shows high shrinkability in a lengthwise direction or a major shrinkage direction, has high mechanical strength in a widthwise direction, hardly generates a wrinkle in a manufactured film roll, and shows good perforation openabilty. <P>SOLUTION: The heat-shrinkable polyester film shrinks mainly in the lengthwise direction. It is adjusted in each predetermined range for a warm water heat shrinkage ratio in the lengthwise direction after treatment for 10 seconds at 90°C in warm water, a warm water heat shrinkage ratio in the widthwise direction after treatment for 10 seconds at 90°C in warm water, indices of refraction in the lengthwise and widthwise directions, and a natural shrinkage ratio after ageing for 700 hours or more under an atmosphere of 65% RH and 40°C. <P>COPYRIGHT: (C)2008,JPO&INPIT |
