| 摘要 |
<p>PURPOSE:To obtain a film roll of ideal roll shape having little wrinkle, streak, and the like by a method wherein a center line average thickness variation and a thickness variation average crest-to-crest spacing as indexes of a thickness variation are so determined as to meet specific general formulas. CONSTITUTION:Using one or more thickness meters, the thickness of uniaxially- or/and biaxially-oriented thermoplastic resin film is measured. Using a computer, these data are analyzed. By a feed back or/and feed forward system, a die lip slot is adjusted so that a center line average thickness variation TVa and a thickness variation average crest-to-crest spacing TVsm meet formulas I and II [L is a film length (m) in an integration section, f(x) is a thickness variation curve when a center line of a thickness variation is an X axis, f(x) is an average thickness variation in the section L, S is a distance between crests (m) in a thickness variation, and (n) is the number of crests in a thickness variation]. In this manner, a film roll of ideal roll shape having little wrinckle, streak, and the like is obtained while a high productivity is maintained.</p> |
