| 摘要 |
PURPOSE:To prevent cohesions between films and to eliminate the breaking of a tubular film during heat treatment, by folding the both ends of a tubular film into a specific shape, and by tenter heat-treating the film held by clips. CONSTITUTION:The biaxially drawn tubular thermoplastic resin film 1 is folded into such shapes that the both ends may be zigzag 2n layers and the center may be two layers (n is an integer). The 2n layer parts are held by the tentering clips 8 and heat-treated to form a space layer between the central two layers due to the shrinkage of the film 1, thus heat-treating the film 1 without causing mutual cohesion. |
