US5476589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porpous PTFE film and a manufacturing method therefor
Assignee: W.L. Gore and Associates Inc
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Filing: 1995-03-10
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Granted: 1995-12-19
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Expires: 2015-03-10
Abstract
Abstract A nonwoven web is described that is a thin porous polytetrafluoroethylene membrane consisting essentially of a nonwoven web having a microstructure of substantially only microfibrils fused at crossover points. It is usually strong, is unusually thin, has unusually small pore sizes, but a very high air flow-through. It has a pore size between 0.05 and 0.4 micrometers; a bubble point between 10 and 60 psi; a pore size distribution value between 1.05 and 1.20; a ball burst strength between 0.9 and 17 pounds/force; an air flow of between 20 Frazier and 10 Gurley seconds; a thickness between 1.0-25.4 micrometer; and a fiber diameter ranging between 5 and 200 nm.
Inventors
- 👤 John Bacino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:08
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1692; B01D67/00; B01D67/0002; B01D67/0023; B01D67/0025; B01D67/0027; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B29; B29C; B29C55/00; B29C55/02; B29C55/04; B29C55/06; B29C55/065; B29C55/08; B29C55/085; B29C55/10; B29C55/12; B29C55/14; B29C55/146; D; D04; D04H; D04H1/00; D04H1/40; D04H1/42; D04H1/4282; D04H1/4318; B01D2325/00; B01D2325/02; B01D2325/0281; B01D2325/04; B01D2325/20; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
82 words
A thin porous polytetrafluoroethylene membrane consisting essentially of a nonwoven web having a microstructure of substantially only microfibrils fused at crossover points, said membrane having: (a) a pore size between 0.05 and 0.4 micrometers; (b) a bubble point between 10 and 60 psi; (c) a pore size distribution value between 1.05 and 1.20; (d) a ball burst strength between 0.9 and 17 lbs./Force; (e) an air flow of between 20 Frazier number and 10 Gurley seconds; (f) a thickness between 1-25.4 micrometers.
Claim 2
Dependent Claim
82 words
A thin porous polytetrafluoroethylene membrane consisting essentially of a nonwoven web having a microstructure of substantially only microfibrils fused at crossover points, said membrane having: (a) a pore size between 0.05 and 0.4 micrometers; (b) a bubble point between 10 and 60 psi; (c) a pore size distribution value between 1.05 and 1.20; (d) a ball burst strength between 0.9 and 17 lbs./Force; (e) an air flow of between 20 Frazier number and 10 Gurley seconds; (f) a thickness between 1-25.4 micrometers.
Claim 3
Dependent Claim
43 words
The membrane of claim 1 wherein the pore size is between 0.05 and 0.2 micrometer; the bubble point is between 20-55; the air flow is between 10 Frazier Number and 6 Gurley Seconds; and the fiber diameter is between 5 and 200 nm.
Claim 4
Dependent Claim
58 words
Process for preparing the membrane of claim 1 which comprises employing a relatively thick extruded lubricated film of polytetrafluoroethylene about 20-30 mils thick or more and processing it by stretching traversely less than 3 X, drying, then stretching longitudinally 10-100 X, then longitudinally again between 1:1 and 1.5:1 X, and again traversely stretching while constraining the film shrinking.
References Cited (Backward Citations)
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