US4157328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sealing material on the basis of polytetrafluoroethylene fibers
Assignee: Hoechst AG
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Filing: 1977-09-15
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Granted: 1979-06-05
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Expires: 1997-09-15
Abstract
Abstract The invention describes a sealing material from polytetrafluoroethylene fibers, whose staple length is in the range of from 1 to 20 mm. They are intimately mixed with graphite; oil and finely divided polytetrafluoroethylene being advantageously added. The portion of PTFE fibers is at least 50% by weight, the portion of graphite is from 10 to 30% by weight, and the portion of finely divided PTFE is from 5 to 15% by weight. As PTFE fibers there are also used those which have been obtained by machining sintered PTFE resin. The sealing material is formed into tablets or half-rings. The seals prepared are marked by their applicability at uncommonly high pressures.
Inventors
- 👤 Gerhard Beyer
- 👤 Gerhard Wolfel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:09
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/18; F16J15/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
62 words
A sealing material from polytetrafluoroethylene which consists essentially of an intimate mixture of at least 50% by weight of polytetrafluoroethylene of cut staple fibers having a length of 1 to 20 millimeters, from 10% to 30% by weight of graphite powder and from 5% to 25% by weight of finely divided polytetrafluoroethylene having an average particle size of 0.1 to 30 microns.
Claim 2
Dependent Claim
62 words
A sealing material from polytetrafluoroethylene which consists essentially of an intimate mixture of at least 50% by weight of polytetrafluoroethylene of cut staple fibers having a length of 1 to 20 millimeters, from 10% to 30% by weight of graphite powder and from 5% to 25% by weight of finely divided polytetrafluoroethylene having an average particle size of 0.1 to 30 microns.
Claim 3
Dependent Claim
19 words
Sealing material as claimed in claim 1, wherein the PTFE fibers have been obtained by machining sintered PTFE resin.
Claim 4
Dependent Claim
22 words
Sealing material as claimed in claim 1, wherein the graphite used has a purity of more than 95%, especially more than 99%.
Claim 5
Dependent Claim
82 words
A sealing material from polytetrafluoroethylene consisting essentially of at least 50% by weight of polytetrafluoroethylene cut fibers having a staple length of 1 to 10 millimeters, a diameter of 0.1 to 3 mm and a titer of 2 to 50 dtex, 10% to 30% by weight of graphite powder, 5% to 25% by weight of finely divided polytetrafluoroethylene having an average particle size of 0.1 to 30 microns and a lubricant selected from silicone oil, paraffin oil, mineral oil and polyhydric alcohols.
Claim 6
Dependent Claim
82 words
A sealing material from polytetrafluoroethylene consisting essentially of at least 50% by weight of polytetrafluoroethylene cut fibers having a staple length of 1 to 10 millimeters, a diameter of 0.1 to 3 mm and a titer of 2 to 50 dtex, 10% to 30% by weight of graphite powder, 5% to 25% by weight of finely divided polytetrafluoroethylene having an average particle size of 0.1 to 30 microns and a lubricant selected from silicone oil, paraffin oil, mineral oil and polyhydric alcohols.
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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) | 1982-06-04 | 1982-12-04 | 1983-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-04 | 1986-12-04 | 1987-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-04 | 1990-12-04 | 1991-06-05 | $7700.00 | Window Closed / Lapsed |