| 摘要 |
PURPOSE:To control effectively the generation of wrinkles and folding lines on a film by installing a means for transferring a sag generated in the film behind a guide member and then installing a folding means comprising rolls in front of the film. CONSTITUTION:In a method in which a ring-shaped film is formed by extruding a molten raw material resin such as an aromatic polyester, a gas is supplied into a inner space while being cooled, a cylindrical stretched film is formed, and the film is extracted through a guide member while being folded into a sheet form, a width spreading means 5 having a function for transferring a sag generated in a film 3 to the end of the film, e.g. an expanding roll 9, is installed behind a guide member 4, and then a folding means 6 comprising two or more rolls which are arranged not to come into contact with each other through the film is placed in front of the film 3. |
