| 摘要 |
PURPOSE:To improve the planeness of the film concerned and remove the nonuniformity of its quality by a method wherein film having the predetermined water absorption coefficient is produced by longitudinally stretching polyester ether in multiple stages and, after that, stretching laterally. CONSTITUTION:By stretching polyester ether laterally after stretching it longitudinally in multiple stages, film having water absorption coefficient of 0.6wt.% or more, preferably 0.8-5.0wt.% is obtained. As the structural component of polyester ether, aromatic dihydric acid and glycol are exampled. As the dihydric acid, terephthalic acid, isophthalic acid or the like is employed. As the glycol, ethylene glycol, propylene glycol or the like is employed. Among the polyester ether consisting of the above-mentioned components, one mainly consisting of polyethyleneterephthalate, cyclohexane dimethylene terephthalate and polyethylene naphthalate is preferable. Thus, film, which is excellent is planeness and has no nonuniformity in quality, is obtained. |
