| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a simultaneous biaxial stretched polyamide film having uniform and excellent quality stability by reducing material unevenness caused by stretching unevenness which is a problem in a simultaneous biaxial stretching method, specifically minimizing the enlargement of thickness unevenness based on the collapse of stress deformation balance cause by stress relaxation. SOLUTION: The simultaneous biaxial stretching method is carried out by a tenter method in which the width direction edge parts of an unstretched film are gripped with clips and the film is biaxially stretched lengthwise and crosswise simultaneously. Until a crosswise stretching locus reaches a maximum stretch ratio, a lengthwise stretching locus which is given by a straight line distance between the adjacent clips is prevented from decreasing by 5% or more of a maximum lengthwise stretching ratio. COPYRIGHT: (C)2009,JPO&INPIT |
