EP0646151B1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Surface modified porous expanded polytetrafluoroethylene and process for making

Assignee: W.L. Gore and Associates Inc

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Filing: 1992-06-08

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Granted: 1997-11-05

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Expires: 2012-06-08

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Abstract

Abstract Porous expanded polytetrafluoroethylene material having a microstructure of nodes interconnected by fibrils wherein a surface of the material has been modified to have increased hydrophobicity as indicated by having a water droplet roll-off angle of less than about 10 degrees in comparison to a typical roll-off angle of greater than about 12 degrees for the unmodified material. Under magnification, the surface morphology may be indistinguishable from that of the unmodified precursor material. The modification is preferably done by exposing the surface to radio frequency gas plasma discharge with a reactive etching gas for a lengthy amount of time such as about ten minutes. If surface etching is continued beyond a time adequate to produce the highly hydrophobic behavior, then the surface morphology includes the appearance of broken fibrils. Still further treatment results in complete removal of fibrils from the surface so that under magnification the surface has the appearance of freestanding node portions not interconnected by fibrils but rather having open valleys disposed between the freestanding node portions.

Inventors

👤 Stanislaw L. Zukowski

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-10-23 13:28

CPC Classifications

C; C08; C08J; C08J5/00; C08J5/18; A; A01; A01K; A01K91/00; A01K91/12; A61; A61L; A61L27/00; A61L27/14; A61L27/16; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1692; B29; B29C; B29C59/00; B29C59/14; A61L2400/00; A61L2400/18; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; F; F23; F23G; F23G2202/00; F23G2202/20; F23L; F23L2900/00; F23L2900/07005; Y; Y02; Y02E; Y02E20/00; Y02E20/34; Y10; Y10S; Y10S128/00; Y10S128/14; Y10S55/00; Y10S55/05; Y10S623/00; Y10S623/901; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1362; Y10T428/1372; Y10T428/139; Y10T428/1397; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249958; Y10T428/249962; Y10T428/249964; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/2935; Y10T428/2973; Y10T428/2975; Y10T428/31; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T442/00; Y10T442/60

Claims Analysis

Total Claims: 9

Claim 1

Independent Claim 38 words

Porous expanded polytetrafluoroethylene having a microstructure of nodes interconnected by fibrils, comprising a three dimensional material having surfaces and having a water droplet roll-off angle less than 10 degrees on a substantial portion of at least one surface.

Claim 2

Dependent Claim 18 words

Porous expanded polytetrafluoroethylene according to claim 1 wherein the water droplet roll-off angle is less than 4 degrees.

Claim 3

Dependent Claim 32 words

Porous expanded polytetrafluoroethylene according to either of claims 1 or 2 wherein the three dimensional material is in the form of a tubular shape having an inner surface and an outer surface.

Claim 4

Dependent Claim 24 words

Porous expanded polytetrafluoroethylene according to either of claims 1 or 2 wherein the three dimensional material is in the form of a flat sheet.

Claim 5

Dependent Claim 40 words

Porous expanded polytetrafluoroethylene according to either of claims 1 or 2 wherein the three dimensional material is in the form of a cylindrical shape having a curved outer surface and the at least one surface comprises the curved outer surface.

Claim 6

Dependent Claim 33 words

Porous expanded polytetrafluoroethylene according to any preceding claim wherein the substantial portion of the at least one surface is comprised of freestanding node portions with open valleys disposed between the freestanding node portions.

Claim 7

Independent Claim 95 words

A method of modifying a surface of a porous expanded polytetrafluoroethylene material, said porous expanded polytetrafluoroethylene material having a microstructure of modes interconnected by fibrils, said method comprising exposing the surface to a radio frequency gas plasma discharge with a reactive etching gas until the fibrils are removed from at least a substantial portion of the surface and the surface is comprised of freestanding node portions with open valleys disposed between the freestanding node portions, and at least the substantial portion of the surface has a water droplet roll-off angle of less than 10 degrees.

Claim 8

Dependent Claim 26 words

A method according to claim 7 wherein at least the substantial portion of the surface was a water droplet roll-off angle of less than 4 degrees.

Claim 9

Independent Claim 69 words

A method of modifying a surface of a porous expanded polytetrafluoroethylene material said porous expanded polytetrafluoroethylene material having a microstructure of nodes interconnected by fibris, said method comprising exposing the surface to a reactive gas plasma discharge until the fibrils are removed from at least a substantial portion of the surface and the surface is comprised of freestanding node portions with open valleys disposed between the freestanding node portions.

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