Molten production of polyamides from terephthalic acid dialkyl ester and trimethyl hexamethylene diamine under reduced pressure

Abstract

Abstract IN THE PRODUCTION OF POLYAMIDES BY PRE-CONDENSING POLYAMIDE/FORMING REACTANTS IN THE PRESENCE OF WATER, REMOVING WATER, AND THEN POLYCONDENSING TO FORM THE POLYAMIDE, THE IMPROVEMENT WHICH COMPRISES TERMINATING THE POLYCONDENSATION WHE THE VISCOSITY OF THE PRODUCT FALLS IN THE RANGE OF ABOUT 50 TO 90, TRANSFERRING THE MATERIAL AT A TEMPERATURE OF ABOUT 200 TO 300*C. TO A SCREW EXTRUDER HAVING A VACUUM OUTLET, AND ADVANCING SAID MATERIAL THROUGH THE SCREW EXTRUDER WHILE CONTAINING POLYCONDENSATION TO A FINAL ISCOSITY OF ABOUT 116 TO 150. ADVANTAGEOUSLY THE POLYAMIDE WHEN POLYCONDENSATION IS TERMINATED AT A VISCOSITY OF 50 TO 90 IS SENT TO A FEEDER BIN UNDER PRESSURE OF AN INERT GAS AND FROM THERE IS DISCHARGED INTO THE SCREW EXTRUDER. THE RESULTING POLYAMIDES, THOUGH QUITE HARD, ARE LOW MELTING AND THUS LIGHT STABLIZERS CAN BE BLENDED THEREIN AND THE EASIER WORKING WILL NOT DEGRADE THE STABILIZERS SO TRANSPARENT HOLLOW ARTICLES OF IMPROVED APPEARANCE CAN BE MADE BY INJECTION MOLDING.

Inventors

• 👤 J Schneider
• 👤 W Pungs

Bibliographic Details