Process for producing polytrimellitimides with alkylene oxide as hydrogen halide scavenger

Claim 1

IN A PROCESS FOR PRODUCING A POLYAMIDE-IMIDE FOR USE AS A WIRE ENAMEL FROM AN ACID HALIDE OF A BENZENE TRICARBOXYLIC ACID ANHYDRIDE AND AN AROMATIC PRIMARY DIAMINE, WHEREIN THE AROMATIC RADICAL CONSISTS ESSENTIALLY OF DIVALENT MONO AND POLYAROMATIC HYDROCARBONS CONTAINING 1 TO 4 AROMATIC RINGS WHEREIN SAID MULTIPLE RINGS ARE JOINED DIRECTLY OR BY MEMBERS SELECTED FROM THE GROUP CONSISTING OF OXY, SULFONYL, CARBONYL AND LOWER ALKYLENE GROUPS, IN WHICH HYDROGEN HALIDE IS PRODUCED, SAID TRICARBOXYLIC ACID HALIDE AND DIAMINE BEING REACTED AT A FIRST LOWER TEMPERATURE BELOW 150*C. EFFECTIVE TO PRODUCE A POLYAMIDE SOLUBLE IN N,N,-DIMETHYLACETAMIDE WHICH POLYAMIDE IS THEN HEATED AT A SECOND HIGHER TEMPERATURE ABOVE 150*C. EFFECTIVE TO PRODUCE SAID POLYAMIDE-IMIDE INSOLUBLE IN N,N-DIMETHYLACETAMIDE, SAID ACID HALIDE BEING SELECTED FROM THE GROUP CONSISTING OF ACID CHLORIDE AND ACID BROMIDE, THE IMPROVEMENT IN SAID PROCESS COMPRISING SCAVENGING THE ENTRAINED HYDROGEN HALIDE WITH AN ALKYLENE OXIDE CONTAINING 2 TO 4 CARBON ATOMS IN A STRAIGHT CHAIN AND CAPABLE OF FORMING A HALOHYDRIN BOILING BELOW ABOUT 300*C. THUS REDUCING THE CORROSIVE TENDENCIES OF SAID HYDROGEN HALIDE AND IMPROVING THE PROPERTIES OF SAID POLYAMIDE-IMIDE.