Patent US4407988A successfully refreshed from Google Patents.
US4407988A
Expired / Lapsed
US
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Method for preparing a wear-resistant composition containing fluorinated graphite, graphite fibers and PTFE
Assignee: Waters Technologies Corp
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Filing: 1982-03-25
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Granted: 1983-10-04
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Expires: 2002-03-25
Abstract
Abstract A composition suitable for manufacturing into wear-resistant and chemically-inert articles, the composition being a mixture of 74 to 84% polytetrafluoroethylene, 7-17% graphite fibers, and 4-14% fluorinated graphite.
Inventors
- 👤 Louis Abrahams
- 👤 Thomas P. J. Izod
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:52
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/16; C08K7/00; C08K7/02; C08K7/04; C08K7/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
94 words
The method of preparing a composition consisting essentially of a mixture of 74-84% by weight polytetrafluoroethylene, 7-17% graphite fibers and 4-14% fluorinated graphite comprising the steps of: mixing together 74-84 parts by weight of polytetrafluoroethylene in a chlorinated ethane or methane solvent to form a first slurry, mixing 7-17 parts graphite fibers and 4-14 parts fluorinated graphite in a chlorinated ethane or methane solvent to form a second slurry, mixing said first and second slurries to form a third slurry, and draining said third slurry so as to give the mixture a granular consistency.
Claim 2
Independent Claim
94 words
The method of preparing a composition consisting essentially of a mixture of 74-84% by weight polytetrafluoroethylene, 7-17% graphite fibers and 4-14% fluorinated graphite comprising the steps of: mixing together 74-84 parts by weight of polytetrafluoroethylene in a chlorinated ethane or methane solvent to form a first slurry, mixing 7-17 parts graphite fibers and 4-14 parts fluorinated graphite in a chlorinated ethane or methane solvent to form a second slurry, mixing said first and second slurries to form a third slurry, and draining said third slurry so as to give the mixture a granular consistency.
Claim 3
Dependent Claim
33 words
The method of claim 1 comprising the further steps of: mixing said drained third slurry in water to form a fourth slurry, draining and drying said fourth slurry, and sintering the resulting composition.
Claim 4
Dependent Claim
25 words
The method of claim 2 further comprising passing said dried fourth slurry through one or more sieves prior to said sintering step to prevent caking.
Claim 5
Dependent Claim
14 words
The method of claim 2 wherein said chlorinated methane or ethane is methylene chloride.
Claim 6
Dependent Claim
17 words
The method of claim 4 wherein said third slurry is drained at room temperature using a vacuum.
Claim 7
Dependent Claim
15 words
The method of claim 5 wherein said fourth slurry is dried at about 125° C.
Claim 8
Dependent Claim
15 words
The method of claim 2 wherein said first slurry is mixed for about one minute.
Claim 9
Dependent Claim
15 words
The method of claim 2 wherein said third slurry is mixed for about 11/2 minutes.
Claim 10
Dependent Claim
16 words
The method of claim 8 wherein said fourth slurry is mixed by three short high-speed pulses.
Claim 11
Dependent Claim
15 words
The method of claim 6 wherein said fourth slurry is dried for about eight hours.
Claim 12
Dependent Claim
14 words
The method of claim 10 wherein said sieves constitute a #10 and #14 sieve.
Claim 13
Dependent Claim
29 words
The method of claim 1 comprising the further steps of: mixing said dried third slurry in water to form a fourth slurry, and draining and drying said fourth slurry.
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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) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |