| 摘要 |
PURPOSE:To obtain a low-cost tubelike film having no connecting part and to further improve a film thickness accuracy by incorporating thermoplastic polyimide resin as a main ingredient and forming a film in a tube state by a melting extruding method. CONSTITUTION:Thermoplastic polyimide resin is contained as a main ingredient, and a film is formed in a tube state by a melting extruding method. Accordingly, the obtained film has no connecting part, and can sufficiently achieve characteristics of the resin of its material. Since melted viscosity is low, it has a low cost, and excellent dimensional accuracy and film thickness accuracy. Since it is sufficiently dried for use, generation of bubbles in the film due to decomposition of the resin and deterioration of thermoplastic fluidity is prevented. The drying is executed by heat treating in a blast circulating type drying oven at 250 deg.C for 24 hours. Thus, excellent heat resistance, radiation resistance and low water absorption rate are provided. |
