| abstract |
(57) [Summary] [Structure] Paraphenylenediamine 1 mol and 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride 1mo After reacting 1 in a solvent at 30 ° C. for 2 hours, it is heated and reacted at 90 ° C. for 2 hours to give a low thermal expansion polyimide resin having an imidization ratio of 5 to 30%. [Effect] By changing the imidization ratio depending on the heating reaction conditions, it became possible to control the thermal expansion coefficient of the cured film. For this reason, polyimide films having different thermal expansion coefficients can be formed from the same raw material, which has been impossible in the past, and the thermal expansion coefficients of various inorganic and metallic materials as the base can be matched very easily. |