US4589975A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a precursor pitch for carbon fiber
Assignee: JFE Steel Corp
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Filing: 1984-12-27
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Granted: 1986-05-20
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Expires: 2004-12-27
Abstract
Abstract A method of producing a precursor pitch for use in the production of carbon fibers, which comprises hydrogenating a soft or middle tar pitch to obtain a hydrogenated pitch containing no free carbon and high molecular weight components and then subjecting it to a heat treatment. In this method, the hydrogenation is carried out in the presence of tetralin at a temperature of 400 DEG -450 DEG C., and the heat treatment after the removal of solvent insoluble components and solvent is carried out in an inert gas atmosphere at a temperature of 450 DEG -500 DEG C. and under a reduced pressure of 0.1-10 Torr.
Inventors
- 👤 Kozo Yudate
- 👤 Yukihiro Ohsugi
- 👤 Mamoru Kamishita
- 👤 Ken Nagasawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:16
CPC Classifications
C; C10; C10C; C10C1/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
138 words
In a method of producing a precursor pitch for carbon fiber by hydrogenating a tar pitch to obtain a hydrogenated pitch containing no free carbon and high molecular weight components, and then subjecting it to a heat treatment, the improvement which comprises carrying out said hydrogenation for a soft or middle pitch as the coal tar pitch, in the presence of tetralin as a solvent at a temperature of 400°-450° C., removing the tetralin and its insoluble components from the hydrogenated pitch, and after said removing step carrying out said heat treatment in an inert gas atmosphere at a temperature of 450°-500° C. and under a reduced pressure of 0.1-10 Torr, so as to obtain a low viscosity mesophase pitch containing 10-30% by weight of quinoline insoluble matter, and having 100% optically anisotropic texture as the precursor pitch.
Claim 2
Dependent Claim
138 words
In a method of producing a precursor pitch for carbon fiber by hydrogenating a tar pitch to obtain a hydrogenated pitch containing no free carbon and high molecular weight components, and then subjecting it to a heat treatment, the improvement which comprises carrying out said hydrogenation for a soft or middle pitch as the coal tar pitch, in the presence of tetralin as a solvent at a temperature of 400°-450° C., removing the tetralin and its insoluble components from the hydrogenated pitch, and after said removing step carrying out said heat treatment in an inert gas atmosphere at a temperature of 450°-500° C. and under a reduced pressure of 0.1-10 Torr, so as to obtain a low viscosity mesophase pitch containing 10-30% by weight of quinoline insoluble matter, and having 100% optically anisotropic texture as the precursor pitch.
Claim 3
Dependent Claim
23 words
The method as claimed in claim 1, wherein said soft or middle pitch and tetralin are hydrogenated in a mixing ratio of 1:1˜1:5.
Claim 4
Dependent Claim
13 words
The method as claimed in claim 2, wherein said mixing ration is 1:2˜1:3.
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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) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |