CO-SOLVENT ACCELERATOR AND PROCESS FOR TRANSFORMING A POLYIMIDE POLYAMIDE-ACID SOLUTION

摘要

The invention relates to a CO-SOLVENT ACCELERATOR. The CO-SOLVENT ACCELERATOR OF THE INVENTION INCLUDES CERTAIN POLAR APROTIC SOLVENTS WITH A HIGH BOILING POINT, SUCH AS N, N- DIMETHYLACETAMIDE AND SOLVENTS BASED ON PYRROLIDONE, IN PARTICULAR THOSE HAVING A BOILING POINT ABOVE ABOUT 250C. THESE CO-SOLVENTS ARE USED IN CONCENTRATIONS OF ABOUT 0.5 TO ABOUT 10 BY WEIGHT, PREFERABLY FROM 3 TO ABOUT 10 BY WEIGHT. / P P THE CO-SOLVENT ACCELERATOR OF THE INVENTION IS USED TO ACCELERATE THE TRANSFORMATION OF A POLYAMIDE-ACIDETHER SOLUTION TO A POLYIMIDE. / P