| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an oriented high strength polyimide film in which mechanical properties, particularly Young modulus, are improved by high orientation. SOLUTION: A method for producing the polyimide film comprises the following steps; a solution (1) of a polyamic acid is prepared, the solution (1) is allowed to flow on a supporting article to give a film, the film together with the supporting article is immersed in a solution obtained by dissolving dicyclohexylcarbodiimide into at least one solvent selected from the solvent used in the solution (1), whereby there is formed a gel like film wherein at least a part of the polyamic acid is converted into polyisoimide, the produced film is separated from the supporting article, and biaxially stretched and subjected to heat treatment. The fundamental approach of the method is to conduct imidization after stretching the gel like film. The gel like film is formed by introducing the polyamic acid solution into a solution of a condensation agent, and swelled by a solvent upon stretching. COPYRIGHT: (C)2007,JPO&INPIT |
