Pall Corporation

Stanley W Kidd

David Edward Newman

Franco Morizio

Thomas C Gsell

Gregory S Carpenter

Munaf Tinwala

Membranes having parallel channels in a surface of the membranes, wherein the channels have side walls having rough surfaces; filters and devices including at least one membrane, and methods of making and using the membranes, are disclosed.

Membrane with surface channels

The present invention provides integral porous membranes comprising an amorphous halopolymer, as well as processes for preparing the membranes, and devices comprising the membranes. An example of an amorphous halopolymer is a copolymer of tetrafluoroethylene and perfluoro-2,2-dimethyl-1,3-dioxole.

Porous membrane

The present invention relates to microporous and ultrafine polytetrafluoroethylene (PTFE) membranes of high permeability, excellent mechanical strength, and good chemical inertness, and to methods for their preparation. According to the method of the present invention, a porous PTFE substrate having a first pore rating is compressed to provide a porous membrane having a second pore rating, wherein the second pore rating is smaller than the first pore rating. The PTFE substrate can be contacted with one or more fibrous sheets during the compression step, which is preferably performed by passing the substrate, and fibrous sheets, if appropriate, between two calender rolls. The resulting porous PTFE membrane then can optionally be stretched and/or sintered, and preferably has a water permeability of at least about 0.5 l/hr/m,/kPa.

Porous polytetrafluoroethylene membrane

The present invention relates to microporous and ultrafine polytetrafluoroethylene (PTFE) membranes of high permeability, excellent mechanical strength, and good chemical inertness, and to methods for their preparation. According to the method of the present invention, a porous PTFE substrate having a first pore rating is compressed to provide a porous membrane having a second pore rating, wherein the second pore rating is smaller than the first pore rating. The PTFE substrate can be contacted with one or more fibrous sheets during the compression step, which is preferably performed by passing the substrate, and fibrous sheets, if appropriate, between two calender rolls. The resulting porous PTFE membrane then can optionally be stretched and/or sintered, and preferably has a water permeability of at least about 0.5 l/hr/m.sup.2 /kPa.

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Westbury, NY, United States of America

Stanley W Kidd