Asymmetric membranes of polytetrafluoroethylene and process for

Details Asymmetric membranes of polytetrafluoroethylene and process for Asymmetric membranes of polytetrafluoroethylene and process for

1995-05-15

1997-08-05

Drodge, Joseph W.

Liquid purification or separation

Filter

Supported, shaped or superimposed formed mediums

96 4, 21050036, 264 41, 427245, B01D 2905, B01D 7126

Patent

active

056538820

ABSTRACT:
This invention relates to methods for preparing membranes of polyfluoroethylene (PTFE) and to the asymmetric membranes fabricated thereby. Such membranes are useful as separation and ultrafiltration membranes. The membranes are produced as a single layer. Method steps including contacting a substrate with a solution of PTFE in a perfluorinated cycloalkane solvent at a high temperature to cause a film of such solution to be coated on the substrate, removing the coated substrate from the solution and rapidly cooling it by contact with a second solvent, removing the coated substrate from the second solvent, drying the film, and optionally separating film from substrate.

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