Patent ID: 7060782
Filing Date: 2006-06-13
Classification: C08G

Abstract:
1. A process for a two stage melt polymerization for the production of polybenzimidazole in a first stage and in a second stage which comprises the first stage steps of: providing a first reaction vessel having a means for agitation and a means for controlling atmosphere; charging said reaction vessel having a means for agitation and a means for controlling atmosphere; charging said reaction vessel with at least one aromatic hydrocarbon tetraamine containing two pairs of amine substituents on an aromatic ring in ortho position and a dicarboxylic component consisting of at least one compound having the formula: In which R′ is a divalent organic radical of the class consisting of an aromatic hydrocarbon ring, an alkylene group, and a heterocyclic ring and may be the same or different in the various molecules making up the dicarboxylic component and tye Y's may be hydrogen, aryl or alkyl with no more than 95% of the Y's being hydrogen or phenyl to create a reaction mass; Heating said reactants under agitation in a substantially oxygen-free atmosphere with agitation until the agitator torque is from abut 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 degree to 350 degree C. while allowing said reaction mass to foam; cooling said reaction mass to a friable foamed mass; crushing said friable foamed mass to obtain a ground prepolymer; and starting the second stage which comprisies the steps of: agitation and a means for controlling pressure or vacuum, said second reaction vessel being a high intensity reaction vessel; transferring said ground prepolymer to said second reaction vessel; heating said ground prepolymer under agitation to between 315° to 400° at atmospheric pressure for a time between 90 minutes and 400 minutes.