Patent US4066737A successfully refreshed from Google Patents.
US4066737A
Expired / Lapsed
US
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Method for making isotropic carbon fibers
Assignee: Koppers Inc
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Filing: 1973-03-02
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Granted: 1978-01-03
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Expires: 1993-03-02
Abstract
Abstract Isotropic carbon fibers are disclosed and a method is disclosed for making them from liquid hydrocarbon distillates comprising reacting the distillate with elemental oxygen to produce a pitch-like product which will yield isotropic carbon upon subsequent carbonization, forming the pitch-like product into a filament and carbonizing the filament in an inert atmosphere at temperatures in excess of 800° C wherein the distillate is reacted with the oxygen until at least 0.5 standard cubic feet of elemental oxygen is reacted per pound of distillate.
Inventors
- 👤 George R. Romovacek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:45
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/145; D01F9/15; D01F9/32; D01F9/322
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A method for preparing isotropic carbon fibers from hydrocarbon distillates selected from coal tar distillates boiling between about 200° to 400° C, straight run petroleum distillates boiling between about 200° to 600° C and catalytically cracked recycle petroleum distillates boiling between about 200° to 500° C comprising: a. reacting the distillate with a gas containing elemental oxygen at a temperature of from about 250° to about 420° C until at least 0.5 standard cubic foot of elemental oxygen is reacted per pound of distillate and the distillate is converted to a pitch like substance which yields isotropic carbon upon subsequent carbonization; b. forming a fiber from the oxidized hydrocarbon distillate; c. carbonizing the fiber in an inert atmosphere at temperatures in excess of 800° C.
Claim 2
Independent Claim
125 words
A method for preparing isotropic carbon fibers from hydrocarbon distillates selected from coal tar distillates boiling between about 200° to 400° C, straight run petroleum distillates boiling between about 200° to 600° C and catalytically cracked recycle petroleum distillates boiling between about 200° to 500° C comprising: a. reacting the distillate with a gas containing elemental oxygen at a temperature of from about 250° to about 420° C until at least 0.5 standard cubic foot of elemental oxygen is reacted per pound of distillate and the distillate is converted to a pitch like substance which yields isotropic carbon upon subsequent carbonization; b. forming a fiber from the oxidized hydrocarbon distillate; c. carbonizing the fiber in an inert atmosphere at temperatures in excess of 800° C.
Claim 3
Dependent Claim
14 words
A method as in claim 1 wherein the gas containing elemental oxygen is air.
Claim 4
Dependent Claim
25 words
A method as in claim 1 wherein the oxidized distillate is distilled to remove the low boiling constituents prior to being formed into a fiber.
Claim 5
Independent Claim
147 words
A method for preparing isotropic carbon fibers from hydrocarbon distillates selected from coal tar distillates boiling between about 200° to 400° C, straight run petroleum distillates boiling between about 200° to 600° C and catalytically cracked recycle petroleum distillates boiling between about 200° to 500° C comprising: a. reacting the distillate with a gas containing elemental oxygen at a temperature of from about 250° to about 420° C until at least 0.5 standard cubic foot of elemental oxygen is reacted per pound of distillate and the distillate is converted to a pitch-like substance which yields isotropic carbon upon subsequent carbonization; b. distilling the oxidized distillate until it has a cube in air softening point of from about 80° C to about 200° C; c. forming a fiber from the oxidized hydrocarbon distillate; d. carbonizing the fiber in an inert atmosphere at temperatures in excess of 800° C.
Claim 6
Independent Claim
147 words
A method for preparing isotropic carbon fibers from hydrocarbon distillates selected from coal tar distillates boiling between about 200° to 400° C, straight run petroleum distillates boiling between about 200° to 600° C and catalytically cracked recycle petroleum distillates boiling between about 200° to 500° C comprising: a. reacting the distillate with a gas containing elemental oxygen at a temperature of from about 250° to about 420° C until at least 0.5 standard cubic foot of elemental oxygen is reacted per pound of distillate and the distillate is converted to a pitch-like substance which yields isotropic carbon upon subsequent carbonization; b. distilling the oxidized distillate until it has a cube in air softening point of from about 80° C to about 200° C; c. forming a fiber from the oxidized hydrocarbon distillate; d. carbonizing the fiber in an inert atmosphere at temperatures in excess of 800° C.
Claim 7
Dependent Claim
13 words
A method as in claim 4 wherein the oxygen containing gas is air.
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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) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |