Method for making polyetherimide

A process for the continuous polymerization of polyetherimide which comprises (1) dry-blending aromatic bis(ether anhydride) and organic diamine, (2) feeding the resulting solids into an extruder, (3) conveying the solids to a melting stage in the extruder, where they are kneaded and melted via viscous heating at a temperature in the range of from about 50.degree. C. to about 300.degree. C. resulting in the production of a liquid pool, (4) conveying the liquid of (3) to a mass transfer stage where water of reaction is vented to the atmosphere at temperatures of from 200.degree. C. to 350.degree. C., (5) conveying the resulting melt from the mass transfer stage of (4) to an advanced polymerization stage where the melt is further subjected to higher shear and intensive mixing at a temperature in the range of from 300.degree. C. to 400.degree. C. while being subjected to pressures of 1 atmospheres to 25 atmospheres, and (6) and thereafter separating from the extruder polyetherimide and additional water of reaction.

A process for the continuous, steady state polymerization of polyetherimides consisting essentially of chemically combined units of the formula, ##STR25## (1) dry-blending aromatic bis(ether anhydride) of the formula, ##STR26## and the organic diamine has the formula, H.sub.2 N--R.sup.1 --NH.sub.2, (2) continuously introducing the dry-blended solids of (1) to an extruder, (3) continuously conveying the blended solids to a melting stage in the extruder, where they are rapidly converted to a liquid as a result of being subjected to kneading conditions at a temperature in the range of from about 50.degree. C. to about 300.degree. C., (4) continuously conveying the liquid of (3) to a first extruder mass transfer stage to effect separation of water of reaction resulting in polyetherimide formation based on the intercondensation of the aromatic bis(ether anhydride) and organic diamine, (5) continuously conveying the viscous polyetherimide product of reaction from the first mass transfer stage of (4) to a mixing stage where the intercondensation product of reaction is subjected to high shear at a temperature in the range of from about 250.degree. C. to 350.degree. C. and elevated pressures to further polymerize the polyetherimide, (6) conveying said further polymerized polyetherimide to a second mass transfer stage where further melt pool acceleration, polymerization, and evacuation of water of reaction are accomplished, (7) conveying said further polymerized polyetherimide from said second mass transfer stage to an advanced polymerization stage where complete polymerization of said polyetherimide is accomplished with extended residence time, and (8) removing a high polymer polyetherimide from said advanced polymerization stage with removal of final water of reaction, where R is a member selected from ##STR27## and divalent organic radicals of the general formula, ##STR28## X is a member selected from the class consisting of divalent radicals of the formula, ##STR29## y is an integer from 1 to 5; and R.sup.1 is a divalent organic radical selected from the class consisting of aromatic hydrocarbon radicals having from 6 to about 20 carbon atoms and halogenated derivatives thereof, alkylene radicals having from 2 to about 20 carbon atoms, cycloalkylene radicals having from 3 to about 20 carbon atoms, from C.sub.2 to about C.sub.8 alkylene terminated polydiorganosiloxanes and divalent radicals of the general formula, ##STR30## Q is a member selected from the class consisting of --O--, --S--, C.sub.x H.sub.2 x, x is an integer from 1 to 5 and n is 0 or 1.