E.i. Dupont De Nemours and Company

John M Iwasyk

Albert W Alsop

Kenneth Wayne Leffew

David Neil Marks

Elwood Neal Blanchard

Jan M Stouffer

Jeffrey David Cohen

Robert D Sauerbrunn

Clara Young Lin

Julie Anderson Rakestraw

David A Douglas, Jr

Earl W Blackwell

A valve capable of controlling fluid flow at high temperatures and high-pressures. The valve can shut off or regulate flow and combines a small compact shape with the ability to be remotely operated and the ability to process a diverse variety of fluids including polymer melts at extreme temperatures and pressures including two phase fluids. The valve includes a process diaphragm that deflects to seat against a valve seat, a control diaphragm that deflects to contact against a stop surface, and a cylindrical actuating button therebetween. The actuating button has respective end surfaces that contact against the process diaphragm and the control diaphragm. The button end surfaces on the button are spaced apart by a button length. When assembled, the distance between the valve seat and the stop surface is greater than the button length by about the sum of the deflections of the diaphragms.

Control valve for extreme temperatures and pressures

Disclosed is a process for the preparation of polyamide polymers via prepolymer formation in a reactor system comprising a reactor, flasher and separator, crystallization of the prepolymer under controlled temperature conditions and the subsequent conversion of these crystallized prepolymers to high molecular weight polymer.

Process for preparing polyamides

This invention is directed to an improved process for producing a polyester oligomer. The process employs a pipeline reactor, having at least two stages, in which the degree of polymerization of an oligomeric feed material is raised from about 2-10 to about 2-40 and the ratio of carboxyl to hydroxyl end groups in the product is reduced. In a first stage of the process, a monomeric diol or polyol, such as ethylene glycol, is added to a melt of the oligomeric feed material. In a second stage of the process, the molecular weight of the oligomer is increased by removal of volatile reaction by-products, including water and polyol. The oligomer produced by the present invention may be used in making higher molecular weight polyesters.

Process for polymerization of polyester oligomers

The present invention relates to an apparatus for processing materials, a process for mixing, finishing and de-volatizing polyamide to make 66 nylon and the 66 nylon made by this process. The apparatus comprises an agitator section having an outlet adjacent the bottom thereof; a transfer screw disposed adjacent the outlet of the agitator section; a spiral ribbon extending upwardly from the transfer screw; a ring disposed vertically above the spiral ribbon, at least one baffle disposed vertically above the spiral ribbon and connected to the ring and a wall-wiping spur connected to the ring. Preferably, the apparatus has two baffles--an upper one for pumping the material downwardly and a lower one for pumping the material upwardly. The diameter of each baffle is preferably about 80% of the diameter of the agitator section.

Continuous process for preparing a synthetic linear, fiber-forming

Apparatus for processing materials

An apparatus for separating entrained matter from a flowing fluid carrying the entrained matter includes a passage diverging at an angle of from 3 to about 20 degrees in the direction of flow of the fluid and at least one helical flight having the same twist direction throughout located with the passage and tapered to conform thereto. A straight cylindrical pipe is attached to the outlet end of the passage; the pipe contains a straight baffle interlocking to aboout 90 degrees with the helical flight. Opposed edges of the flight may be spaced from or in contact with the wall of the diverging passage.

Modified nozzles for polymer finishers

An improved polymerization apparatus for finishing high viscosity synthetic polymers involves a vessel having vertical rotating elements which fully wipe the interior surface of the vessel including the top inner surface. Entrances located in the top of the vessel for feeding streams containing molten polymer downwardly into the vessel deposit fresh polymer on the walls and on the upper element surfaces which wipe the top inner surface. A reservoir formed by the leading edge of a raised portion on the upper end surface of the elements facilitates collecting and spreading a fresh supply of polymer on the top inner surface of the vessel to help eliminate stagnant polymer areas thereon during operation.

Apparatus for finishing high viscosity synthetic polymers

A continuous process for preparing polyamides is improved by providing a pressurized reactor in which steam is evolved along with some diamine volatilization while providing for diamine re-absorption by contact and mixing (with a static mixer) of the vapor and liquid phases in annular flow in the reactor.

Growing community of inventors

Wilmington, DE, United States of America

John M Iwasyk