| 主权项 |
1. A plastic film joining method in which a composite film is composed of external and internal films opposed to and superposed with each other, to have opposite end portions, the composite film being opposed to and superposed with an additional body, the method including joining the external and internal films and the additional body with each other at one of the end portions so that a first joining portion should be formed between the external and internal films, a second joining portion being formed between the internal film and the additional body, the first joining portion having a first joining width and including first outer and inner edges formed by the first joining width, the second joining portion having a second joining width and including second outer and inner edges formed by the second joining width, the method comprising:
making an adjustment of the first or second joining width, the first joining width being less than the second joining width so that the first inner edge should be formed outwardly of the second inner edge. |
