| abstract |
Novel polyimide solutions are provided which are obtained by reacting 1,2,3,4-butane tetracarboxylic acid or a functional derivative thereof with an organic diamine for example an aromatic diamine such as diaminodiphenyl ether in certain reaction solvents for example phenols, nitrobenzenes, pyridines, quinolines, N-alkyl lactams and cyanobenzenes at a temperature of from 100* C. to the boiling point of the reaction mixture until a polyimide solution is obtained having an imidization ratio of 5098 percent is obtained. The products thus obtained can be employed as varnishes, to make film coating for electric cable, as adhesives or blended with pigments and the like to make pains. |