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Patent US5234751A successfully refreshed from Google Patents.
US5234751A
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Porous material of polytetrafluoroethylene and process for producing the same
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1992-04-29
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Granted: 1993-08-10
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Expires: 2012-04-29
Abstract
Abstract A porous material of polytetrafluoroethylene consisting essentially of fibers of polytetrafluoroethylene. The porous material of PTFE is produced by heat-treating a molded article prepared by paste extruding of PTFE fine powder under such a condition that the heat-treated molded article shows at least one endothermic peak which appears between an endothermic peak position of the fine powder and an endothermic peak position of a sintered product thereof on a differential scanning calorimeter chart and then is stretched along at least one direction.
Inventors
- 👤 Akira Harada
- 👤 Hiroshi Mano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:14
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B01; B01D; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B29; B29C; B29C55/00; B29C55/005; B29K; B29K2027/00; B29K2027/12; B29K2027/18; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249979; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T442/00; Y10T442/10; Y10T442/184
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
80 words
A porous material of polytetrafluoroethylene characterized in that it is produced by steps including paste-extrusion, heat-treatment and stretching which is carried out at a stretch ratio of higher than 1.5 times and further characterized in that said porous material has a network structure consisting essentially of fibers of polytetrafluoroethylene and has an IPA bubble point of higher than 1.0 kg/cm 2 , an IPA solvent shrinkage ratio of lower than 15%, and a Gurley number of less than 100 sec.
Claim 2
Dependent Claim
80 words
A porous material of polytetrafluoroethylene characterized in that it is produced by steps including paste-extrusion, heat-treatment and stretching which is carried out at a stretch ratio of higher than 1.5 times and further characterized in that said porous material has a network structure consisting essentially of fibers of polytetrafluoroethylene and has an IPA bubble point of higher than 1.0 kg/cm 2 , an IPA solvent shrinkage ratio of lower than 15%, and a Gurley number of less than 100 sec.
Claim 3
Dependent Claim
35 words
The porous material of polytetrafluoroethylene set forth in claim 1 wherein said porous material has an IPA bubble point of higher than 3.0 kg/cm 2 and an IPA solvent shrinkage ratio of lower than 30%.
Claim 4
Dependent Claim
85 words
The porous material of polytetrafluoroethylene set forth in claim 1 wherein said porous material is obtained by heat-treating a non-sintered molded article prepared by paste extrusion of polytetrafluoroethylene fine powder under such a condition that the heat-treated molded article shows at least one endothermic peak which appears between an endothermic peak position of the fine powder and an endothermic peak position of a sintered product thereof on a differential scanning calorimeter chart and then by stretching the heat-treated molded article along at least one direction.
Claim 5
Dependent Claim
20 words
The porous material of polytetrafluoroethylene set forth in claim 1 wherein said porous material has a shape of a sheet.
Claim 6
Dependent Claim
18 words
The porous material of polytetrafluoroethylene set forth in claim 1 wherein the network structure has substantially no nodes.
Claim 7
Dependent Claim
17 words
The porous material of polytetrafluoroethylene set forth in claim 1 which is produced by stretching after heat-treatment.
Claim 8
Dependent Claim
81 words
A process for producing a porous material of polytetrafluoroethylene characterized in that a non-sintered molded article prepared by extruding a paste of polytetrafluoroethylene fine powder is subjected to a heat-treatment under such a condition that the heat-treated molded article shows at least one endothermic peak which appears between an endothermic peak position of the fine powder and an endothermic peak position of a sintered product thereof on a differential scanning calorimeter chart and then is stretched along at least one direction.
Claim 9
Dependent Claim
81 words
A process for producing a porous material of polytetrafluoroethylene characterized in that a non-sintered molded article prepared by extruding a paste of polytetrafluoroethylene fine powder is subjected to a heat-treatment under such a condition that the heat-treated molded article shows at least one endothermic peak which appears between an endothermic peak position of the fine powder and an endothermic peak position of a sintered product thereof on a differential scanning calorimeter chart and then is stretched along at least one direction.
Claim 10
Dependent Claim
29 words
The process set forth in claim 7 wherein said non-sintered molded article is stretched along at least two directions at an areal stretch ratio of more than 5 times.
Claim 11
Dependent Claim
20 words
The process set forth in claim 7 wherein the stretching is effected at a temperature between 0° and 300° C.
Claim 12
Dependent Claim
17 words
The process set forth in claim 7 wherein the heat-treated molded article is further heated after stretching.
Claim 13
Dependent Claim
21 words
The process set forth in claim 10 wherein said the heat-treated molded article is heated at a temperature above 200° C.
Claim 14
Dependent Claim
21 words
The process set forth in claim 11 wherein said the heat-treated molded article is heated at a temperature above 347° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |