| 摘要 |
PROBLEM TO BE SOLVED: To stabilize production and to improve toughness, oil resistance, anti- static properties, gas shielding properties and transparency by using an ethylene- vinyl alcohol copolymer with a specified compsn. and selecting a specified manufacturing condition. SOLUTION: An ethylene-vinyl alcohol copolymer with ethylene unit of 25-45mol%, crystalline particle size obtd. by using Shehler's equation from a half-value width of a (101) diffraction peak measured by X-ray diffraction method of 30-60Åand a degree of face orientation obtd. from 10×(180-half value width)/180 of at least 85%, is used. Namely, after an undrawn film consisting of the ethylene-vinyl alcohol copolymer like this absorbs 2-10wt.% water, it is preheated at 70-90 deg.C and then, after it is simultaneously biaxially oriented 2.5-5.0-folds in the longitudinal and transverse direction and so as to make facial orienting ratio of 8-15-folds at a temp. being 5-10 deg.C higher than the temp. of preheating, heat treatment under relaxation of at most 15% in the width direction of the film is performed at 150-170 deg.C. |
