E.i. Dupont De Nemours and Company

Ramdas Dujari

Gregory D Cramer

Robert Clayton Wheland

David Neil Marks

Sundar M Rao

Colin Anolick

Daniel Gregory Tynan

Win-Chung Lee

An improved method for increasing the relative viscosity and molecular weight of a polyamide polymer (such as nylon 6,6, nylon 6, and the like) while in the solid state involving the use of a phosphorus-containing catalyst (such as 2(2'-pyridyl) ethyl phosphonic acid or the like) in combination with an oxygen free gas characterized by a low dew point (typically below 30.degree. C. and preferably below -30.degree. C.). The combination of affording commercial operation at greater through put at lower temperature. Such a process is of particular value during the production of terpolyamide and multipolyamide polymer intended for use in colored nylon fiber manufacture.

Method for solid phase polymerization

A linear polyamide having a weight average molecular weight above 200,000 is made by heating a lower molecular weight molten polyamide with thorough mixing at a temperature of about 265.degree.-300.degree. C. for at least 5 minutes while an inert gas is swept gently through the reactor, the increase of molecular weight of the polyamide being catalyzed by a particular phosphinic acid derivative.

Linear very high molecular weight polyamides and process for producing

This invention concerns a process for increasing the molecular weight and viscosity of polyamides and other condensation polymers, by first injecting an inert gas into the polymer melt at elevated pressure, then stripping the volatiles from the polymer through the application of reduced pressure, followed by holding the polymer at elevated temperatures long enough for the reaction to occur. Activators may be added to the polymer. Port areas used in the stripping zone, may be kept hot for continuous operation.

Process for increasing the molecular weight of polyamides and other

Disclosed is a process for preparing nylon by adding an amidation catalyst concentrated in 'masterbatches' to the process melt resulting in a product with increased molecular weight and viscosity.

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Seaford, DE, United States of America

Ramdas Dujari