Patent US4861575A successfully refreshed from Google Patents.
US4861575A
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Method of producing carbon fibers by overwrappings tows
Assignee: BP Corp North America Inc
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Filing: 1986-05-08
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Granted: 1989-08-29
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Expires: 2006-05-08
Abstract
Abstract Carbon fibers may be made by a process comprising: overwrapping a multifilament polyacrylonitrile tow with a thread of material to maintain the tow as an integral bundle, followed by stabilizing said tow by heating in an oxidizing atmosphere at a temperature between about 180° and about 400° C., thereby oxidizing the filaments comprising said tow, followed by carbonizing the tow thus stabilized by heating at a temperature sufficient to effect carbonization, thereby forming a carbon fiber. The carbon fibers may be used to make reinforced composites in thermoplastic or thermosetting matrix resins, particularly prepreg.
Inventors
- 👤 Chris D. Levan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:22
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
51 words
A method of making carbon fibers, comprising the steps of: (a) overwrapping a multifilament polyacrylonitrile tow with a 10 to 150 denier thread; (b) stabilizing said tow by heating in an oxidizing atmosphere at a temperature between about 180° and about 400° C.; and (c) carbonizing the stabilized tow by heating.
Claim 2
Independent Claim
51 words
A method of making carbon fibers, comprising the steps of: (a) overwrapping a multifilament polyacrylonitrile tow with a 10 to 150 denier thread; (b) stabilizing said tow by heating in an oxidizing atmosphere at a temperature between about 180° and about 400° C.; and (c) carbonizing the stabilized tow by heating.
Claim 3
Dependent Claim
66 words
In a process for the production of carbon fiber wherein a multifilament tow comprising a plurality of polyacrylonitrile fibers is oxidized by heating in an oxidizing atmosphere, then carbonized by heating at an elevated temperature for a time sufficient to carbonize an oxidized polyacrylonitrile fiber, the improvement comprising overwrapping said multifilament tow with at least one 10 to 150 denier thread prior to oxidizing the tow.
Claim 4
Dependent Claim
66 words
In a process for the production of carbon fiber wherein a multifilament tow comprising a plurality of polyacrylonitrile fibers is oxidized by heating in an oxidizing atmosphere, then carbonized by heating at an elevated temperature for a time sufficient to carbonize an oxidized polyacrylonitrile fiber, the improvement comprising overwrapping said multifilament tow with at least one 10 to 150 denier thread prior to oxidizing the tow.
Claim 5
Dependent Claim
15 words
The process of claim 2 wherein the thread is removed prior to the carbonizing step.
Claim 6
Dependent Claim
20 words
The process of claim 2 wherein the thread is selected from cellulosic thread, fiberglass thread, carbon thread and ceramic thread.
Claim 7
Dependent Claim
16 words
The process of claim 2 wherein the thread is oxidized and destroyed during the oxidizing step.
References Cited (Backward Citations)
US3775520A
Cited
US3809673A
Cited
US4237175A
Cited
US4378343A
Cited
US4501037A
Cited
US4534919A
Cited
JPS61113826A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |