US4985296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polytetrafluoroethylene film
Assignee: W.L. Gore and Associates Inc
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Filing: 1989-03-16
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Granted: 1991-01-15
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Expires: 2009-03-16
Abstract
Abstract A filled PTFE film is prepared by compressing an expanded, porous PTFE film that contains filler material. The films have high strength with substantially few pinholes.
Inventors
- 👤 William P. Mortimer, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:20
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/02; B29C55/18; C08K; C08K3/00; C08K3/01; C08K3/013; C08L; C08L27/00; C08L27/02; C08L27/12; C08L27/18; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/06; B29K2105/16; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
33 words
A thin film of filled polytetrafluoroethylene that: (a) contains 25-85 volume percent particulate filler, (b) has a film thickness of between 0.1 and 5 mil, and (c) is substantially free of visual pinholes.
Claim 2
Dependent Claim
33 words
A thin film of filled polytetrafluoroethylene that: (a) contains 25-85 volume percent particulate filler, (b) has a film thickness of between 0.1 and 5 mil, and (c) is substantially free of visual pinholes.
Claim 3
Dependent Claim
20 words
The thin film of claim 1 wherein the film has an unsintered matrix tensile strength of at least 3500 psi.
Claim 4
Dependent Claim
17 words
The film of claim 1 wherein the thickness of the film is between 0.1 and 2 mil.
Claim 5
Dependent Claim
17 words
The film of claim 1 wherein the thickness of the film is between 0.2 and 1.5 mil.
Claim 6
Dependent Claim
61 words
The film of claim 1, 2, 3 or 4 wherein the filler is selected from the class consisting of titanium dioxide, barium titanate, aluminum oxide, glass fiber, glass particulate, carbon black, carbon/metal particulate, activated carbon, ceramic particulate, and polyether ether ketone; and the filler content is at least 40% by volume based on total volume of film excluding any void space.
Claim 7
Dependent Claim
16 words
A film of claim 1, 2, 3 or 4 wherein the filler is of high dielectric.
Claim 8
Dependent Claim
16 words
A film of claim 1 wherein the dielectric constant of the film is greater than 7.
Claim 9
Dependent Claim
19 words
A film of claim 1 wherein the filler is a fiber having an aspect ratio of 3:1 or greater.
Claim 10
Dependent Claim
19 words
A film of claim 1 wherein the filler is titanium dioxide present in an amount of 40-85 volume percent.
Claim 11
Dependent Claim
18 words
A film of claim 1 wherein the filler is barium titanate present in an amount of 40-85 percent.
Claim 12
Dependent Claim
18 words
A film of claim 1 wherein the filler is glass fiber present in an amount of 10-40 percent.
Claim 13
Dependent Claim
18 words
A film of claim 1 wherein the filler is glass particulate in an amount of 30-85 volume percent.
Claim 14
Dependent Claim
18 words
A film of claim 1 wherein the filler is aluminum oxide in an amount of 40-85 volume percent.
Claim 15
Dependent Claim
18 words
A film of claim 1 wherein the filler is carbon black in an amount of 40-85 volume percent.
Claim 16
Dependent Claim
19 words
A film of claim 1 wherein the filler is polyether ether ketone in an amount of 25-85 volume percent.
Claim 17
Dependent Claim
85 words
Process comprising: (a) mixing 25-85 volume percent particulate filler of an average size of 40 micron or less with polytetrafluoroethylene in aqueous dispersion, (b) cocoagulating the filler and the polytetrafluoroethylene, (c) lubricating the filled polytetrafluoroethylene with lubricant, (d) (i) calendering or (ii) paste extruding and optionally calendering, to form a film, (e) expanding said film by stretching it so as to form an expanded porous polytetrafluoroethylene having said filler distributed therein, (f) densifying the stretched material by compressing it until a desired thickness is obtained.
Claim 18
Dependent Claim
85 words
Process comprising: (a) mixing 25-85 volume percent particulate filler of an average size of 40 micron or less with polytetrafluoroethylene in aqueous dispersion, (b) cocoagulating the filler and the polytetrafluoroethylene, (c) lubricating the filled polytetrafluoroethylene with lubricant, (d) (i) calendering or (ii) paste extruding and optionally calendering, to form a film, (e) expanding said film by stretching it so as to form an expanded porous polytetrafluoroethylene having said filler distributed therein, (f) densifying the stretched material by compressing it until a desired thickness is obtained.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-14 | 1994-07-16 | 1995-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-14 | 1998-07-16 | 1999-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-14 | 2002-07-16 | 2003-01-15 | $7700.00 | Window Closed / Lapsed |