| 摘要 |
PROBLEM TO BE SOLVED: To keep stably a beautiful appearance by making great a heat shrinkage coefficient to prevent an unevenness in shrinkage by a method wherein the heat shrinkage coefficient in one direction of a film and a moisture content of the film at a specific temperature are allowed to have specific values. SOLUTION: A heat shrinkage coefficient in one direction of a film at 100 deg.C is set to 40% or over, and a moisture content of the film is set to 1000 to 10000 ppm. As a dicarboxylic acid composition comprising a polyester in a raw material composition, excepting a terephthalic acid comprising an ethylene terephthalate unit, either of an aromatic dicarboxylic acid and a cyclic dicarboxylic acid is acceptable. The raw material composition is molded in, for example, a film state or a tube state by, for example, an extrusion method or a calendar method. Further, as the control of the moisture content, for example, a method wherein an extruded film-shaped molded product is dipped in warm water or in water before drawing, a method wherein heated steam is jetted to the film, a method of passing through wet atmosphere, a method of using a wet drawing machine, or the like are adopted. |
