| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for relaxation heat treatment of a biaxially oriented film which enables long-time continuous production of a film of a low heat shrinkage percentage having no flaw in the surface of the film. SOLUTION: In the method for relaxation heat treatment of the biaxially oriented polyester film, the film is subjected to the relaxation heat treatment between a tenter and a pair of draw-off rollers subsequent to this, conveyed then by a plurality of groups of conveying rolls and wound up continuously by a winder. There is no nip roll for nipping the film over the whole width thereof in the take-up rollers and the groups of the conveying rolls. The surface temperature of the take-up rollers is 55-85°C, while the percentage of heat shrinkage of the wound film in the lengthwise direction under the condition of 150°C×30 minutes is 0.1-0.6%. COPYRIGHT: (C)2003,JPO |
