| 摘要 |
PURPOSE:To obtain a film having high dimensional stability under heat and bondable easily to a metal, etc., at high temperature, by polymerizing a biphenyltetracarboxylic acid and a phenylenediamine compound, forming a thin film from the obtained polymer solution, drying and heat-treating the film, and again heat-treating the product. CONSTITUTION:A biphenyltetracarboxylic acid and a phenylenediamine compound are polymerized in a polar organic solvent to obtain a polymer solution, which is converted to a thin film on the surface of a substrate. The thin film is dried to obtain a solidified film containing about 20-60wt% solvent. The film is peeled off from the substrate, and dried and heat-treated at about 200-500 deg.C fixing at least a pair of opposite side edges. The obtained aromatic polyimide film is heat-treated again at 330-500 deg.C under a low tension, i.e. <=400g/mm<2>.
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