| 摘要 |
PURPOSE:To provide a polyimide film having excellent resistance to alkalis and heat and a high softening point, by mixing two specified kinds of polyimide precursors, molding the mixture into a film and converting it into a polyimide. CONSTITUTION:5-95wt% polyimide precursor (A) obtd. by reacting an arom. tetracarboxylic acid dianhydride (derivative) mainly composed of bisphenyltetracarboxylic dianhydride (derivative) of the formula with an arom. diamine such as m-phenylenediamine, is mixed with 95-5wt% polyimide precursor (B) obtd. by reacting an arom. tetracarboxylic acid dianhydride (derivative) mainly composed of pyromellitic dianhydride (derivative) with an arom. diamine. The mixture is dissolved in an org. polar solvent such as dimethylformamide and cast on a smooth plate to form a film which is then heated to convert it into a polyimide, thus obtaining the desired polyimide film.
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