| 摘要 |
PROBLEM TO BE SOLVED: To prepare a heat-shrinkable polyester film used for a label for a bottle, particularly having a paper-like appearance on the surface, in particular, an appearance like that of Japanese paper with little occurrence of wrinkles due to shrinkage, nonuniformity in shrinkage, and strain. SOLUTION: The heat-shrinkable polyester film is characterized in that the difference in film thickness per a length of 1 cm between the main shrinkage direction of the film and the direction perpendicular to the main shrinkage direction thereof is 3μm or greater, it contains pores in the inside, the average pore diameter in one surface part at least in the direction of film thickness is below 5μm, the average pore diameter in the central part in the direction of film thickness is 15μm or greater, the average roughness (Ra) along the center line on the surface of the film at least on one side is 0.1μm or greater, and the tear propagation resistance in the direction perpendicular to the main shrinkage direction after 10% shrinkage in the main shrinkage direction is 1,500 mN or lower. COPYRIGHT: (C)2004,JPO |
