| 摘要 |
PURPOSE:To improve the heat resistance by forming a film consisting essentially of an amorphous thermoplastic polyetherimide resin. CONSTITUTION:The film consisting essentially of the amorphous thermoplastic polyetherimide resin having a prescribed repeat unit is formed to obtain a center cap 3 of a diaphragm 1. Materials which does not change the shape even if they are left for 2hr at 150 deg.C are used as materials of the cap 3. |
