Process for production of polyamides

Claim 1

A CONTINUOUS PROCESS FOR THE PRODUCTION OF LINEAR POLYAMIDES WHICH COMPRISES INTRODUCING INTO A FIRST ZONE AN AQUEOUS SOLUTION OF APPROXIMATELY EQUIMOLAR PARTS OF AN ALIPHATIC, SATURATED DICARBOXYLIC ACID AND AN ALKYLENE DIAMINE HAVING TWO PRIMARY AMINO GROUPS, CONDENSING SAID ALIPHATIC, SATURATED, DICARBOXYLIC ACID AND SAID ALKYLENE DIAMINE IN THE FORM OF A POLYAMINE IN SAID FIRST ZONE BY EVAPORATING AT SUPERATMOSPHERIC PRESSURE BETWEEN ABOUT 15 AND 20 ATMOSPHERES A MAJOR PORTION OF THE WATER IN SAID FIRST ZONE AT A TEMPERATURE SUFFICIENTLY HIGH TO KEEP THE CONDENSED POLYAMIDE IN A FLUID STATE IN SAID PRESSURIZED FIRST ZONE, REMOVING THE EVAPORATED WATER FROM SAID FIRST ZONE, CONTINUOUSLY WITHDRAWING FROM SAID FRIST ZONE A POLYAMIDE MOLTEN MASS STILL CONTAINING ABOUT 8-13* BY WEIGHT OF WATER, BASED ON THE MOLTEN MASS, AND CONTINUOUSLY INTRODUCING THE MOLTEN MASS WITHDRAWN FROM SAID FRIST ZONE INTO INTO A SECOND ZONE MAINTAINED AT SUPERATMOSPHERIC PRESSURE BETWEEN ABOUT 15 AND 20 ATMOSPHERES AND FURTHER CONDENSING SAID POLYAMIDE INTRODUCED INTO SAID SECOND ZONE BY EVAPORATING FROM THE MOLTEN MASS ADDITIONAL WATER BY INTIMATELY COMINGLING THE MOLTEN MASS WITH A PREHEATED, SUBSTANTIALLY DRY, INERT, GASEOUS FLUID IN SAID PRESSURIZED SECOND ZONE WHILE MAINTAINING THE TEMPERATURE IN SAID SECOND ZONE ABOVE THE MELTING POINT OF THE POLYAMIDE THEREIN, WHEREBY THE WATER IN THE MOLTEN MASS EVAPORATES INTO SAID GASEOUS FLUID, CONTINUOUSLY WITHDRAWING THE POLYAMIDE FROM SAID SECOND ZONE, AND REMOVING THE WATER VAPOR-LADEN GASEOUS FLUID FROM SAID SECOND ZONE.