Patent US4025679A successfully refreshed from Google Patents.
US4025679A
Expired / Lapsed
US
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Fibrillated polytetrafluoroethylene woven filter fabric
Assignee: Gore Enterprise Holdings Inc
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Filing: 1976-08-06
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Granted: 1977-05-24
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Expires: 1996-08-06
Abstract
Abstract The product of the present invention is a fabric woven from oriented polytetrafluoroethylene (PTFE) strands, in which the strands of the weave are interconnected by a multiplicity of fine PTFE fibrils. To produce this fabric, consisting entirely of PTFE, a woven PTFE fabric is heated substantially unrestrained to a temperature above the crystalline melt point of PTFE and stretched. Alternatively, a woven PTFE fabric may be impregnated with other fluorocarbon polymers, heated substantially unrestrained to a temperature above the crystalline melt point of PTFE, and subsequently stretched, thereby generating a multiplicity of fine fibrils interconnecting the weave.
Inventors
- 👤 Thomas E. Denny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:58
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/08; B01D39/083; B29; B29C; B29C61/00; B29C61/06; B29C61/0608; B29C61/0658; D; D03; D03D; D03D15/00; D03D15/20; D03D15/283; D03D15/40; D03D15/41; D03D15/50; D03D15/587; B01D2239/00; B01D2239/04; B01D2239/0464; B01D2239/12; B01D2239/1233; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; D10; D10B; D10B2321/00; D10B2321/04; D10B2321/042; D10B2505/00; D10B2505/04; Y; Y10; Y10S; Y10S55/00; Y10S55/45; Y10T; Y10T428/00; Y10T428/23907; Y10T428/2395; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T442/00; Y10T442/30; Y10T442/3065; Y10T442/3089
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
47 words
A fabric woven from strands of polytetrafluoroethylene in which said fabric possesses a multiplicity of fine fibrils of a fluorocarbon polymer interconnecting said strands, which fibrils are separated from each other by void spaces and are anchored at their opposite ends in said strands of said fabric.
Claim 2
Dependent Claim
47 words
A fabric woven from strands of polytetrafluoroethylene in which said fabric possesses a multiplicity of fine fibrils of a fluorocarbon polymer interconnecting said strands, which fibrils are separated from each other by void spaces and are anchored at their opposite ends in said strands of said fabric.
Claim 3
Dependent Claim
22 words
The fabric of claim 1 in which said fine fibrils are anchored at their opposite ends in different strands of said fabric.
Claim 4
Dependent Claim
23 words
The fabric of claim 1 in which said fine fibrils are anchored at their opposite ends in the same strand of said fabric.
Claim 5
Dependent Claim
14 words
The fabric of claim 1 in which said fine fibrils are composed of polytetrafluoroethylene.
Claim 6
Dependent Claim
20 words
The fabric of claim 1 in which said fine fibrils have lengths of about 5 micron to about 300 microns.
Claim 7
Dependent Claim
17 words
The fabric of claim 1 in which said fine fibrils have diameters of about 0.25- 3 microns.
Claim 8
Dependent Claim
86 words
A process for the manufacture of a fabric woven from strands of polytetrafluoroethylene and having a multiplicity of fine fibrils of polytetrafluoroethylene polymer interconnecting said strands of said fabric which comprises: (a) heating a woven fabric of polytetrafluoroethylene strands to a temperature above the crystalline melt point of polytetrafluoroethylene in the absence of substantial restraining forces, thereby allowing said fabric to shrink, followed by (b) stretching said shrunken fabric in one or more directions thereby forming said fine fibrils in the interstices between said woven strands.
Claim 9
Dependent Claim
86 words
A process for the manufacture of a fabric woven from strands of polytetrafluoroethylene and having a multiplicity of fine fibrils of polytetrafluoroethylene polymer interconnecting said strands of said fabric which comprises: (a) heating a woven fabric of polytetrafluoroethylene strands to a temperature above the crystalline melt point of polytetrafluoroethylene in the absence of substantial restraining forces, thereby allowing said fabric to shrink, followed by (b) stretching said shrunken fabric in one or more directions thereby forming said fine fibrils in the interstices between said woven strands.
Claim 10
Dependent Claim
15 words
The process of claim 7 wherein said heating is at a temperature above 365° C.
Claim 11
Dependent Claim
16 words
The process of claim 7 wherein said heating is at a temperature of about 385° C.
Claim 12
Dependent Claim
16 words
The process of claim 7 wherein said heating is at a temperature of about 400° C.
Claim 13
Dependent Claim
16 words
The process of claim 7 wherein said heating is at a temperature of about 410° C.
Claim 14
Dependent Claim
16 words
The process of claim 7 wherein said heating is at a temperature of about 425° C.
Claim 15
Dependent Claim
22 words
The process of claim 7 wherein the dimensions of the shrunken fabric are about 25% of the original dimensions of the fabric.
Claim 16
Dependent Claim
22 words
The process of claim 7 wherein the dimensions of the shrunken fabric are about 50% of the original dimensions of the fabric.
Claim 17
Dependent Claim
22 words
The process of claim 7 wherein the dimensions of the shrunken fabric are about 75% of the original dimensions of the fabric.
Claim 18
Dependent Claim
28 words
The process of claim 7 wherein said stretching increases the dimensions of the fabric to more than 1.25 times the dimensions of the fabric in the shrunken state.
Claim 19
Dependent Claim
27 words
The process of claim 7 wherein the stretching increases the dimensions of the fabric to about 1.50 times the dimensions of the fabric in the shrunken state.
Claim 20
Dependent Claim
27 words
The process of claim 7 wherein the stretching increases the dimensions of the fabric to about 2.00 times the dimensions of the fabric in the shrunken state.
Claim 21
Dependent Claim
27 words
The process of claim 7 wherein the stretching increases the dimensions of the fabric to about 3 times the dimensions of the fabric in the shrunken state.
Claim 22
Dependent Claim
27 words
The process of claim 7 wherein the stretching increases the dimensions of the fabric to about 4 times the dimensions of the fabric in the shrunken state.
References Cited (Backward Citations)
US2578523A
Cited
US3542632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |