| 摘要 |
PURPOSE:To make it possible to produce homogeneous tubular film having uniform section and, at the same time, to stably and uniformly stretch the tubular film so as to obtain wrinkle-free film by a method wherein a heat retaining tube, which retains the heat of the tubular film, is provided between tire expansion starting part of expanding tubular film and guide members. CONSTITUTION:A heat retaining tube 7, which retains the heat of tubular film 6, is provided between the expansion starting part of the tubular film 6 and a pair of guide members 10a and 10b. A pair of the guide members 10a and 10b are arranged in a V-shape so as to guide the opposing faces of the tubular film 6 so as to bring them close to each other. The heat retaining tube 9 consists of an upper sizing ring 9a and a tube 9b, which hangs tubularly from the sizing ring 9a. As the tube 9b to be used, cloth, metal or the like can be cited. By providing the heat retaining tube 9, the elastic modulus of liquid crystalline polymer, resulting in allowing to soften the tubular film 6 so as to fold it. Further, the rolling of the tubular film 6 can be suppressed by the heat retaining tube 9. Accordingly, under the state that wrinkle is prevented from developing, the tubular film 6 can be smoothly folded up. |
