Patent US4574077A successfully refreshed from Google Patents.
US4574077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing pitch based graphite fibers
Assignee: Eneos Corp
•
Filing: 1984-10-10
•
Granted: 1986-03-04
•
Expires: 2004-10-10
Abstract
Abstract Provided is a process for producing a pitch-based graphite fiber, which process comprises treating a pitch fiber in an oxidative gas atmosphere to render it infusible, said pitch fiber being obtained by melt-spinning a carbonaceous pitch, then heat-treating the infusibilized fiber at 400°-750° C. in an inert gas atmosphere to obtain a precarbonized fiber substantially containing oxygen, then raising the temperature to 2,000°-3,000° C. at a rate of 500° C. or higher per minute in an inert gas atmosphere and heat-treating the precarbonized fiber at the raised temperature of 2,000°-3,000° C. in said inert gas atmosphere.
Inventors
- 👤 Seiichi Uemura
- 👤 Takao Hirose
- 👤 Yoshio Sohda
- 👤 Takayoshi Sakamoto
- 👤 Yoshio Kishimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:13
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/145; D01F9/15; D01F9/155
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
A process for producing a pitch-based graphite fiber, which process comprises treating a pitch fiber in an oxidative gas atmosphere to render it infusible, said pitch fiber being obtained by melt-spinning a carbonaceous pitch, then heat-treating the infusiblized fiber at 400°-750° C. in an inert gas atmosphere to obtain a precarbonized fiber containing 1 to 20 percent by weight of oxygen, then raising the temperature to 2,000°-3,000° C. at a rate of 500° C. or higher per minute in an inert gas atmosphere and heat-treating the precarbonized fiber at the raised temperature of 2,000°-3,000° C. in said inert gas atmosphere.
Claim 2
Dependent Claim
100 words
A process for producing a pitch-based graphite fiber, which process comprises treating a pitch fiber in an oxidative gas atmosphere to render it infusible, said pitch fiber being obtained by melt-spinning a carbonaceous pitch, then heat-treating the infusiblized fiber at 400°-750° C. in an inert gas atmosphere to obtain a precarbonized fiber containing 1 to 20 percent by weight of oxygen, then raising the temperature to 2,000°-3,000° C. at a rate of 500° C. or higher per minute in an inert gas atmosphere and heat-treating the precarbonized fiber at the raised temperature of 2,000°-3,000° C. in said inert gas atmosphere.
Claim 3
Dependent Claim
74 words
The process of claim 1, wherein said pitch fiber obtained by melt-spinning the carbonaceous pitch is wound onto a bobbin, then the pitch fiber on the bobbin is treated in the oxidative gas atmosphere and thereby rendered infusible, thereafter the thus-infusiblized fiber is heat-treated in an inert gas atmosphere to obtain the precarbonized fiber, then the precarbonized fiber is unwound from the bobbin and heat-treated at the raised temperature in an inert gas atmosphere.
Claim 4
Dependent Claim
13 words
The process of claim 1, wherein said oxidative gas is oxygen and/or air.
Claim 5
Dependent Claim
27 words
The process of claim 1, wherein said oxidative gas is oxygen and/or air containing 0.1 to 50 percent by volume of SO 2 and/or NO 2 .
Claim 6
Dependent Claim
20 words
The process of claim 1, wherein said carbonaceous pitch has an optically anisotropic phase (mesophase) content of 5 to 100%.
References Cited (Backward Citations)
US3399252A
Cited
US3595946A
Cited
US3974264A
Cited
US3972968A
Cited
US4301136A
Cited
US4389387A
Cited
US4351816A
Cited
US4431623A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-03 | 1989-09-02 | 1990-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-03 | 1993-09-02 | 1994-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-03 | 1997-09-02 | 1998-03-04 | $7700.00 | Window Closed / Lapsed |