HIGHLY HEAT-RESISTANT COATING COMPOSITION, ORGANIC- SOLVENT-SOLUBLE POLYIMIDE, AND HIGHLY HEAT-RESISTANT FILM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a highly heat-resistant coating composition excellent in workability by imparting a solvent solubility to an inherently solvent-insoluble polymer having aromatic rings in the backbone; a solvent-soluble polyimide; and a heat-resistant film and its production method. SOLUTION: This coating composition contains an aromatic resin which is solvent-soluble and is prepared by introducing sulfo groups and/or sulfonate groups or sulfinyl groups and/or sulfinylate groups, as substituents, into an inherently solvent-insoluble, stiff aromatic resin having good mechanical characteristics. The solvent soluble polyimide comprises the solvent-soluble aromatic resin prepared as above. The composition is applied to form a film, which is thermally cured to undergo desulfonation and/or desulfinylation reaction, giving a film having a low thermal expansion coefficient, a high heat resistance, and a low misture absorption.