Polyamide acids in aqs soln from a dianhydride a

摘要

A polyamide acid solution formed in water from (A) at least one dianhydride selected from benzophenone dianhydride, pyromellitic dianhydride, ethylene glycol-bis-trimetliteate anhydride or a dianhydride of the formula (b) at least one diamine selected from C2 to C8 alkylene diamines, m-phenylene diamine or diamines of the formula Where R = a divalent radical selected from alkylene C1 to C3, e.g. ethylene diamine, propylene diamine, 2,2'-oxydianiline, 4,4'-dulphonyl dianiline, and many others listed, and (c) a water soluble tert. amine or tert. amine with a sec. amine, e.g. pyridine, dimethylethanolamine, with or without, e.g., diethylamine or morpholine. The reactants are allowed to interact at below 40 deg.C, e.g. 25-30 deg.C, forming the polyamide acid substantially free from polyimide groups derived from the polyamide acid. More or less equimolar amounts of dianhydride and diamine are used.