| 摘要 |
PURPOSE:To obtain a film having high transparence and high gloss by a method wherein cooling rolls provided between an annular die and nip rolls are rotated at a circumferential speed equal to the running speed of a molten bubble in forming a thermoplastic synthetic resin film by an inflation method. CONSTITUTION:A bubble 3 of thermoplastic synthetic resin such as polyolefin resin fed from an extruder 1 and pushed out of an annular die 2, is inflated to a given width with the inner pressure and then introduced to a pair of cooling rolls 4, 4' rotating a circumferential speed equal to the bubble running speed while maintaining the molten state. Pressure contact with the cooling roll surfaces cools the bulb rapidly and smooth the surface thereof, thus resulting in a solidified tube given with high transparence and gloss. The tube is flattened to become a film 6. In this way, since the cooling rolls 4, 4' are rotated at a circumferential speed equal to the running speed of the bubble 3 and the surface of the cooling rolls is held at a constant temperature, it becomes possible to rapidly solidify the molten bubble 3 and enhance both transparence and gloss of the film 6. |
