| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially stretched polyester film keeping characteristics from a practical aspect without losing heat resistance, aroma retention, water resistance or the like being excellent characteristics of a polyester stretched film, having good twist fixing properties and useful as a twist packaging film. SOLUTION: The biaxially stretched polyester film for twist packaging has an upper yield point and a lower yield point in a stress-strain curve and the ratio (lower yield point strength/upper yield point strength) of the upper and lower yield points is not more than 0.95 and the heat shrinkage factor in the longitudinal direction of the film at 150°C is not more than 5.0%. COPYRIGHT: (C)2004,JPO |
