Patent ID: 7504475

Claim:
A process for a melt polymerization for the production of high molecular weight polybenzimidazole which comprises the steps of: charging a reaction vessel with a plurality of reactants capable of producing a polybenzimidazole to create a reaction mass, said reaction vessel having a means for agitation and a means for controlling atmosphere; heating said reactants under agitation in a substantially oxygen-free atmosphere with agitation until the agitator torque is from about 1.5 to about 6 times the torque before a rise in viscosity begins; terminating the agitation while continuing to heat the reaction mixture to a temperature of from 230° to 350° C. while allowing said reaction mass to foam; cooling said reaction mass to a friable foamed mass; pulverizing said friable foamed mass to obtain a pulverized prepolymer; reheating pulverized prepolymer to a temperature of from 230° to 350° C. for a period of time between 15 minutes and 240 minutes then removing said pulverized prepolymer; pressure washing said reaction vessel and said means for agitation to obtain a resulting wash mixture; separating excess water from said resulting wash mixture to obtain a wet pulverized prepolymer; transferring said pulverized prepolymer and said wet pulverized prepolymer to said reaction vessel; heating said pulverized prepolymer and said wet pulverized prepolymer under agitation to between 315° to 400° C. at atmospheric pressure for a time between 90 minutes and 400 minutes.