Viscosity stabilization of polyamides with ortho-aromatic diamines

Claim 1

A PROCESS FOR THE MANUFACTURE OF HIGH MOLECULAR WEIGH LINEAR FIBER-FORMING POLYCARBONAMIDES WHICH COMPRISES HEATING AND POLYCONDENSING A MATERIAL SELECTED FROM TH GROUP CONSISTING OF AMINO CARBOXYLIC ACIDS AND AN APPROXIMATELY EQUIMOLECULAR MIXTURE OF A HYDROCARBON DIAMINE AND A HYDROCARBON DICARBOXYLIC ACID, AND AMIDE-FORMING FUNCTIONAL DERIVATIVES THEREOF, TOGETHER WITH A MOLECULAR PROPORTION OF FROM 0.5% TO LESS THAN 4%, BASED ON THE QUANTITY OF ACID IN SAID MATERIAL, OF AN AROMATIC COMPOUND THE AROMATIC RING OF WHICH IS SUBSTITUTED BY TWO AMINO GROUPS IN POSITIONS ORTHO TO EACH OTHER AND SELECTED FROM THE CLASS CONSISTING OF UNSUBSTITUTED AMINES AND MONOALKYL SUBSTITUTED AMINES, ONLY ONE OF SAID AMINO GROUPS BEING SUBSTITUTED, ANY OTHER SUBSTITUENT ON THE AROMATIC RING BEING SELECTED FROM THE GROUP CONSISTING OF ALKYL, ARYL, ALKOXY, ARYLOXY, ARALKYL, NITRO, AND HALOGEN, SAID HEATING BEING AT A TEMPERATURE ABOVE THE MELTING POINT OF SAID MATERIAL AND SAID AROMATIC AMINO COMPOUND.