Aqueous solutions of polyamide acids which can be precursors of polyimide polymers

Claim 1

A composition consisting essentially of an aqueous solution of A. 20 to 70% by weight, based on the solution, of a salt of a polyamide acid with a tertiary amine, wherein the polyamide acid is of the general formula ##STR3## wherein one or both G radicals are hydrogen or a carboxyl; atoms and groups wherein → denotes isomerism so that in any recurring unit within the polymeric structure the groups to which the arrows point may exist as shown or in an interchanged position; wherein R is an organic tetravalent radical containing at least two carbon atoms and no more than two carbonyl groups of each polyamide acid unit are attached to any one carbon atom; wherein R 1 is a divalent radical containing at least two carbon atoms, the amide groups of adjacent polyamide acid units are attached to separate carbon atoms of said divalent radical; and wherein n is an integer sufficient to provide a polyamide acid having an inherent viscosity of 0.1-5.0, as measured as a 0.5% solution in N,N-dimethylacetamide at 30° C., and wherein said tertiary amine is present in at least a stoichiometrically equivalent amount to the free carboxylic acid groups in said polyamide acid; B. 5 to 25% by weight, based on the solution, of a viscosity reducing agent which is miscible with water and has a solubility parameter range of 10-20.4 wherein said solubility parameter has a dispersion component in the range of 7.0-10.0, a polar component in the range of 2.0-11.0, and a hydrogen bonding component in the range of 7.0-14.0; C. 5 to 35% by weight, based on the solution, of a coalescing agent, wherein said coalescing agent is at least one member selected from the group consisting of N-methylpyrrolidone, dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, cresylic acid, sulfolane, formamide; and wherein water comprises 30-80% by weight of the solution.