E.i. Dupont De Nemours and Company

Gregory D Cramer

Ramdas Dujari

Robert Clayton Wheland

David Neil Marks

Sundar M Rao

Colin Anolick

Robert D Sauerbrunn

Win-Chung Lee

Albert T Strand

Irvin B King

Roger A Dupre

George H Hitchcock

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

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.

Amidation catalyst concentrates

An analytical sampling valve that permits pumping of a side stream of fluid from a main process fluid stream through a monitoring device to measure fluid stream properties, and return of the sample to the main process line downstream of the sampling position, while providing the ability to clean the lines or remove the monitoring or pumping apparatus without shutdown of fluid flow.

Analytical sampling valve

An apparatus for the analysis of a fluid flowing in a stream includes opposed hollow stems movable in a body member relative to each other. One stem contains a signalling source and the other contains a sensor for the signalling source.

Sensor-holding device

A valve for adding ingredients to or sampling the fluid flowing through the valve includes an adjustable solid stem which can be extended through the flow path of a pipeline to form a seal with a seat positioned directly opposite the stem. An injection nozzle is fitted into the seat to permit addition of ingredients or sampling of the fluid when the stem is retracted from the seat. When the stem is seated, flow still occurs in the flow path.

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Seaford, DE, United States of America

Gregory D Cramer