E.i. Dupont De Nemours and Company

Michael Charles Davis

Michael Allen Bryner

Don Mayo Coates

Larry Ray Marshall

Tom Edward Estep

Ralph A Franke

Charles Wesley Starke

Subhra K Nath

A flash spin pack for a flash-spinning apparatus is provided in which the pack includes a spin mixture inlet, that communicates with a spin mixture passage, that discharges through a spinning orifice that opens into a slot defined by two opposing faces of the body of the spin pack. The slot is 0.25 mm to 7 mm wide proximate the spinning orifice outlet, 0.25 mm to 10 mm at the slot outlet, and the distance from the orifice outlet to the slot outlet is 1.5 mm to 40 mm. The spin pack may have five or more spinning orifices that each discharge into a different slot so configured.

Spinneret with slotted outlet

Process and apparatus for improving web pinning and uniformity in a fibrous web forming operation. The improvements are achieved by imposing an auxiliary electrostatic field above the fibrous web as it is pinned along a moving collection surface. An auxiliary electrostatic field enhancing plate is positioned above the web and collection surface and downstream of the laydown position where the web initially is deposited on the collection surface. The plate enhances the electrostatic field in the region above the collection surface and thereby increases the web pinning forces. When the invention is applied to a flash-spinning process where trifluorochloromethane is used as the fluid medium, an auxiliary electrostatic field of between about 2 and 80 kV/cm, preferably between about 10 and 60 kV/cm, is applied by the plate.

Electrostatic field enhancing process and apparatus for improved web

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Richmond, VA, United States of America

Michael Charles Davis