| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a film of fine appearance with no flaw while reducing the occurrence of thickness unevenness in the width direction of the film in a longitudinal stretching process to solve problems wherein the thickness of both ends of a longitudinally stretched film is thicker than the center part by neck-in in a roll longitudinal stretching process regarding a method for manufacturing a successive biaxially-oriented film for optical use, and the film is liable to break from a chuck portion in a following lateral stretching process to make stable production difficult in a brittle resin film such as an acrylic resin film in particular regarding such a longitudinally stretched film. SOLUTION: In the process for carrying out roll longitudinal stretching of an unstretched molten extruded acrylic resin film, a distance between film holding parts is set large, and roll longitudinal stretching is carried out while giving a temperature gradient in the width direction of the film to be Te>Tc when setting the temperature of both ends of the film in conveyance to Te and the temperature of the center part to Tc between a low peripheral speed roll and a high peripheral speed roll. COPYRIGHT: (C)2010,JPO&INPIT |
