US4576810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbon fiber production
Assignee: ConocoPhillips Co
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Filing: 1983-08-05
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Granted: 1986-03-18
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Expires: 2003-08-05
Abstract
Abstract The oxidation of carbon fibers from pitch is carried out directly by winding the spun fibers on to a spinning spool or bobbin, said spool comprising an open ended, porous, non-expanding or collapsible spool. The spun carbon fibers are wound on such a spinning spool so as to leave open areas between fiber bundles. A mixture of an inert gas such as air or nitrogen containing a minor amount of oxygen is used as the oxidizing gas. Oxidation is carried out in a closed zone, e.g. an oven, for a period of time of at least 4 hours at a temperature that is initially below the glass transistion temperature of the carbon fibers and is slowly increased over the oxidation time to a maximum of about 340° C. The gaseous oxidation atmosphere is continuously recycled and passed through the spool to ensure that the fibers are essentially completely oxidized.
Inventors
- 👤 Hugh E. Redick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:19
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/32; D01F9/322; D01F9/145
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
49 words
A pitch fiber package suitable for direct oxiadation with a gaseous mixture containing oxygen and an inert gas which comprises an open ended, porous, non-expanding or collapsible spool with a densely packed mass of as-spun pitch carbon fibers wound thereon so as to leave open areas between fiber bundles.
Claim 2
Dependent Claim
49 words
A pitch fiber package suitable for direct oxiadation with a gaseous mixture containing oxygen and an inert gas which comprises an open ended, porous, non-expanding or collapsible spool with a densely packed mass of as-spun pitch carbon fibers wound thereon so as to leave open areas between fiber bundles.
Claim 3
Dependent Claim
28 words
The pitch carbon fiber package of claim 1 wherein the spun pitch carbon fibers are wound on the spool with repeated patterns having open areas between fiber bundles.
Claim 4
Independent Claim
173 words
A method for oxidizing spun pitch carbon fibers wound on a spinning spool which comprises winding said pitch carbon fibers on said spool in a manner so that open areas are left between bundles of fibers and so that a densely packed mass of as-spun pitch carbon fibers is formed on said spool; said spool being open ended, porous and non-expanding or collapsible; initiating oxidation of the densely packed as-spun pitch carbon fibers at a temperature below the glass transition temperature of the pitch carbon fibers in a closed heating zone with a gaseous mixture of an inert gas and a minor amount of oxygen; increasing the temperature to a maximum of about 340° C. over a period of time at least sufficient to attain oxygen diffusion to the center of the pitch carbon fibers without loss of crystal orientation in the pitch carbon fibers; and wherein said gaseous oxidation mixture is passed into the open ends of said porous spool and through the open areas between said wound pitch carbon fiber bundles.
Claim 5
Independent Claim
173 words
A method for oxidizing spun pitch carbon fibers wound on a spinning spool which comprises winding said pitch carbon fibers on said spool in a manner so that open areas are left between bundles of fibers and so that a densely packed mass of as-spun pitch carbon fibers is formed on said spool; said spool being open ended, porous and non-expanding or collapsible; initiating oxidation of the densely packed as-spun pitch carbon fibers at a temperature below the glass transition temperature of the pitch carbon fibers in a closed heating zone with a gaseous mixture of an inert gas and a minor amount of oxygen; increasing the temperature to a maximum of about 340° C. over a period of time at least sufficient to attain oxygen diffusion to the center of the pitch carbon fibers without loss of crystal orientation in the pitch carbon fibers; and wherein said gaseous oxidation mixture is passed into the open ends of said porous spool and through the open areas between said wound pitch carbon fiber bundles.
Claim 6
Dependent Claim
11 words
The method of claim 3 wherein said inert gas is nitrogen.
Claim 7
Dependent Claim
21 words
The method of claim 3 wherein the amount of oxygen in said gaseous admixture is about 1 to 15% by volume.
Claim 8
Dependent Claim
11 words
The method of claim 3 wherein said gaseous mixture is air.
Claim 9
Dependent Claim
13 words
The method of claim 3 wherein the initial oxidation temperature is 200° C.
Claim 10
Dependent Claim
17 words
The method of claim 3 wherein the oxidation temperature range is from about 225° to 300° C.
Claim 11
Dependent Claim
15 words
The method of claim 3 wherein the oxidation time period is at least 3 hours.
Claim 12
Dependent Claim
17 words
The method of claim 8 wherein the oxidation time period ranges from about 4 to 8 hours.
Claim 13
Dependent Claim
22 words
The method of claim 3 wherein the spool is made of screen wire, slotted aluminum metal, perforated aluminum metal, and polymeric resin.
Claim 14
Dependent Claim
25 words
The method of claim 3 wherein the spool is made from a multi-ply, multi-directional woven graphite cloth, hoop carbon fiber filaments, and a thermosetting resin.
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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) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |