Polyimide precursor solution, process for producing porous membrane or coated product, polyimide porous membrane, and coating

摘要

PROBLEM TO BE SOLVED: To provide a polyimide precursor solution which can form a polyimide porous film or a coated material having excellent heat resistance and chemical resistance, as well as high porosity, and to provide a polyimide porous film by means of a simple and inexpensive process which does not require a coagulation bath using the polyimide precursor solution.SOLUTION: The polyimide precursor solution is formed by mixing a polyimide precursor comprising a repeating unit represented by general formula (1), a good solvent for the polyimide precursor, and a nonsolvent for the polyimide precursor, which has a boiling point higher by 30°C or more than the good solvent for the polyimide precursor and a 1 wt% solution of which has a coagulation value of 2 g/g or less. [In the formula, B is a tetravalent unit containing an aromatic ring; and A is a divalent unit containing an aromatic ring].