| 摘要 |
PURPOSE:To make a composite film, for which polyvinylidene fluoride is used, joinable firmly and easily, by a method wherein at least an end part of one side film is wrapped in a polyvinylidene fluoride film and this film and the other side film are fused and joined each other at a specific temperature. CONSTITUTION:At the time of joining of composite films 1, 1' obtained by laminating polyvinylidene fluoride films 1a, 1b, 1a', 1b' and core materials 1c, 1c' by turning the films 1a, 1b, 1a', 1b' upside, an end part of at least one side film 1 is wrapped in polyvinylidene fluoride films 2, 3, and the films 2, 3 and the other side film 1' are melted and joined with each other at the temperature of less than 350 deg.C. The end part of the composite film 1 on the outside, for example, is wrapped in a polyvinylidene fluoride film 2 or an end part of a joint of both of the composite films 1, 1' is wrapped in the polyvinylidene fluoride film 3. The joint of the composite films 1, 1' and polyvinylidene fluoride film 2 or 3 are piled up each other and joined with each other through welding by hot pressing in this manner. Though the temperature at the time of joining is decided to be less than 350 deg.C, the temperature falling within a range of 180-350 deg.C is desirable and the range of 230-300 deg.C is more desirable. |
