Preparation of linear cyclic polyimides from latices

Claim 2

A process for preparing a thermoplastic linear cyclic polyimide having a repeating unit ##STR6## wherein R is hydrogen or lower alkyl and R 1 is hydrogen or an organic radical, which comprises adding to latex prepolymer having functional groups selected from the group consisting of carboxyl, amide, alkyl ester and nitrile a nitrogen-containing compound selected from the group consisting of ammonia, a primary amine and hydroxylamine or a mixture thereof, at a temperature of between about 50° C. and 300° C., with the proviso that nitrile functional groups in the latex prepolymer must be employed in a copolymer or terpolymer containing carboxyl groups.

Claim 3

A process according to claim 1 wherein the prepolymer is a copolymer of an α,β-unsaturated acid and an alkyl ester of an α,β-unsaturated acid having the repeating units: ##STR7## wherein R is hydrogen or lower alkyl and R 2 is alkyl of from 1 to 8 carbon atoms.

Claim 4

A process according to claim 2 in which the repeating units are: ##STR8##

Claim 5

A process according to claim 1 in which the reaction temperature is between 100° C. and 240° C.

Claim 6

A process according to claim 1 wherein the prepolymer is a terpolymer having the repeating units: ##STR9## in an amount ranging from 5 to 70% by weight of the prepolymer, ##STR10## in an amount ranging from 5 to 85% by weight of the prepolymer, and ##STR11## in an amount ranging from 0.5 to 20% by weight of the prepolymer, wherein R is hydrogen or lower alkyl, R 2 is alkyl of from 1 to 8 carbon atoms, R 3 is hydrogen, methyl, ethyl or halogen, X 1 is hydrogen or C 1 -C 18 alkoxycarbonyl and X 2 is a member selected from the group consisting of aryl, aminocarbonyl, cyano, C 1 -C 4 alkoxy, carboxy, C 1 -C 18 alkoxycarbonyl, halo, acyl, aldehyde, keto, isocyanato, C 3 -C 9 heterocyclic, C 1 -C 4 alkylene, halomethylene, acetomethylene, sulfo, C 1 -C 4 alkoxysilane and hydrogen.

Claim 7

A process according to claim 5 wherein repeating unit (1) is present in the terpolymer in an amount ranging from 40 to 60% by weight; repeating unit (2) is present in an amount of from 40 to 60% by weight and repeating unit (3) is present in an amount of to 8% by weight.

Claim 8

A process according to claim 1 carried out at about 230° C.

Claim 9

A process according to claim 2 carried out at about 230° C.

Claim 10

A process according to claim 3 carried out at about 230° C.

Claim 11

A process according to claim 5 carried out at about 230° C.