Patent US3972984A successfully refreshed from Google Patents.
US3972984A
Expired / Lapsed
US
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Process for the preparation of carbon fiber
Assignee: Nippon Carbon Co Ltd
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Filing: 1975-02-26
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Granted: 1976-08-03
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Expires: 1995-02-26
Abstract
Abstract A process for the preparation of carbon fibers from polyacrylonitrile type fibers, comprising oxidizing the polyacrylonitrile type fibers to form oxidized fibers therefrom and carbonizing said oxidized fibers in an acidic atmosphere containing a small amount of hydrogen chloride and, if desired, a small amount of moisture with the remainder being an inert gas, thereby obtaining the carbon fibers.
Inventors
- 👤 Masaya Iizuka
- 👤 Nobu Sugiyama
- 👤 Yukuo Hisatomi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:05
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
79 words
A process for the preparation of carbon fibers having improved strength and surface activity, comprising the steps of: heating polyacrylonitrile fibers under tension in an oxidizing atmosphere to produce oxidized fibers, and further heating the thus obtained oxidized fibers in an atmosphere containing from 0.2 to less than 10% by volume of gaseous hydrogen chloride, from 0.5 to 6% by volume of moisture and the remainder an inert gas, to carbonize said oxidized fibers thereby producing said carbon fibers.
Claim 2
Dependent Claim
79 words
A process for the preparation of carbon fibers having improved strength and surface activity, comprising the steps of: heating polyacrylonitrile fibers under tension in an oxidizing atmosphere to produce oxidized fibers, and further heating the thus obtained oxidized fibers in an atmosphere containing from 0.2 to less than 10% by volume of gaseous hydrogen chloride, from 0.5 to 6% by volume of moisture and the remainder an inert gas, to carbonize said oxidized fibers thereby producing said carbon fibers.
Claim 3
Dependent Claim
22 words
The process of claim 1, wherein said further heating of the thus-obtained oxidized fiber is carried out at 1300° to 1500° C.
Claim 4
Dependent Claim
24 words
The process of claim 1, wherein said further heating of the thus-obtained oxidized fiber is carried out for from 1 second to 10 minutes.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein gaseous hydrogen chloride is present in an amount from 0.5 to 6.0% by volume.
Claim 6
Dependent Claim
17 words
The process of claim 1, wherein said moisture is present in an amount from 1.5 to 4.5%.
Claim 7
Dependent Claim
22 words
The process of claim 1, wherein said heating of polyacrylonitrile fibers under tension is carried out at a temperature below 350° C.
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) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |