| 摘要 |
To join together two ends of a flat and tubular thermoplastic film (1), with side folds (2), one end with the inner edges of the side folds has cuts for severing, and the other end is pushed in so that both walls (3,5) each have a layer (4,6) of each side fold between them at the join. The ends are bonded together by a lateral welded seam. The inner edges of the start of the new tubular film are cut away. |
