Process for the production of a random copolymer containing repeating polyimide units and repeating polyetherimide units

Claim 1

A process for the production of a substantially random copolymer containing repeating polyimide units and repeating polyetherimide units comprising: (a) reacting in a first reactor at least one dianhydride of the formula ##STR10## with a diamine of the formula H.sub.2 N--R--NH.sub.2 II under imidization conditions for a time sufficient to produce amine-terminated oligomers; (b) heating in a second reactor at least one dianhydride of the formula ##STR11## and an inert solvent to a temperature equal to or greater than the first reactor; and (c) metering the contents of the first reactor into the contents of the second reactor at a rate of addition such that water can be removed from the reaction mixture as it is formed and heating the resulting mixture for a time sufficient to complete the imidization reaction, wherein the molar ratio of total dianhydride reacted to total diamine reacted is 1:0.5 to 1:2 and from about 78 to 99 mole percent of the total dianhydride is reacted in step (a) and wherein --O--Z--O-- is in the 3 or 3'- and 4 or 4'-positions and Z is a member of the class consisting of (1) ##STR12## and (2) divalent organic radicals of the general formula: ##STR13## where X is a member selected from the class consisting of divalent radicals of the formulas, --C y H 2y --, ##STR14## --O-- and --S-- where q is 0 or 1, y is a whole number from 1 to 5, R is a divalent organic radical selected from the class consisting of (a) aromatic hydrocarbon radicals having from 6 to about 20 carbon atoms and halogenated derivatives thereof, (b) alkylene radicals and cycloalkylene radicals having from 2 to about 20 carbon atoms, C.sub.(2-8) alkylene terminated polydiorganosiloxane, and (c) divalent radicals included by the formula ##STR15## where Q is a member selected from the class consisting of --O--, ##STR16## --S--, and --C x H 2x --, and x is a whole number from 1 to 5 inclusive, and M is a tetravalent radical selected from the class consisting of ##STR17## where B is an electron-withdrawing group.