abstract |
ABSTRACT OF THE DISCLOSURE A water-soluble composition comprising an ammonium salt of a polyimide precursor having a residual acid valve ratio of about 3 to 30%, the ammonium salt of the polyimide precursor comprising the reaction product obtained on reaction of 1,2,3,4-butane tetracarboxylic acid and a diamine in a water-soluble solvent and, optionally, water to obtain a polyimide precursor and followed by formation of the ammonium salt of the polyimide precursor. |