US4671950A
Expired / Lapsed
US
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High-strength carbonaceous fiber
Assignee: Teijin Ltd
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Filing: 1985-11-14
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Granted: 1987-06-09
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Expires: 2005-11-14
Abstract
Abstract A carbonaceous fiber having a carbon content of from 70 to 90%, a high tensile strength and a high modulus of elasticity, which is produced by a method which comprises preoxidizing an acrylic fiber in an oxidizing atmosphere at a temperature of from 10° to 60° C. below the decomposition point of said fiber, to prepare a preoxidized fiber having a degree of orientation of not less than 78% at an angle of X-ray diffraction (2θ) of 25° and a specific gravity of from 1.30 to 1.40, pyrolyzing the preoxidized fiber in an inert gas atmosphere by passing the fiber firstly through a lower temperature zone having a temperature of not higher than 750° C. and then through a higher temperature zone having a temperature of from 750° to 950° C., during the pyrolysis controlling the tension of the fiber so that the change of the fiber length during pyrolyzing is from +16% to -8.8% based on the length of the preoxidized fiber.
Inventors
- 👤 Hiroyasu Ogawa
- 👤 Tetsuro Shigei
- 👤 Hiroshi Sugeno
- 👤 Kazuhiro Ichimaru
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:23
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01F9/32
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
210 words
A carbonaceous fiber having a carbon content of from 70 to 90% by weight, produced by a method which comprises preoxidizing an acrylic fiber in an oxidizing atmosphere at a temperature of from 10° to 60° C. below the decomposition pont of said fiber, to prepare a preoxidizing fiber having a degree of orientation of not less than 78% at an angle of X-ray diffraction (2θ) of 25° and a specific gravity of from 1.30 to 1.40, pyrolyzing the preoxidizing fiber in an inert gas atmosphere by passing the fiber firstly through a lower temperature zone having a temperature of not higher than 750° C., wherein the preoxidized fiber is stretched in the lower temperature zone to an extent of from 40 to 75% of the maximum draw ratio of the fiber at the temperature of said zone, and then through a higher temperature zone having a temperature of from 750° to 950° C., during the pyrolysis controlling the tension of the fiber so that the change of the fiber length during pyrolyzing is from +16 to -8.8% based on the length of the preoxidized fiber, wherein the fiber is shrunk to an extent of from 40 to 80% of the free shrinkage during pyrolyzing in the higher temperature zone.
Claim 2
Dependent Claim
210 words
A carbonaceous fiber having a carbon content of from 70 to 90% by weight, produced by a method which comprises preoxidizing an acrylic fiber in an oxidizing atmosphere at a temperature of from 10° to 60° C. below the decomposition pont of said fiber, to prepare a preoxidizing fiber having a degree of orientation of not less than 78% at an angle of X-ray diffraction (2θ) of 25° and a specific gravity of from 1.30 to 1.40, pyrolyzing the preoxidizing fiber in an inert gas atmosphere by passing the fiber firstly through a lower temperature zone having a temperature of not higher than 750° C., wherein the preoxidized fiber is stretched in the lower temperature zone to an extent of from 40 to 75% of the maximum draw ratio of the fiber at the temperature of said zone, and then through a higher temperature zone having a temperature of from 750° to 950° C., during the pyrolysis controlling the tension of the fiber so that the change of the fiber length during pyrolyzing is from +16 to -8.8% based on the length of the preoxidized fiber, wherein the fiber is shrunk to an extent of from 40 to 80% of the free shrinkage during pyrolyzing in the higher temperature zone.
Claim 3
Dependent Claim
21 words
A carbonaceous fiber as in claim 1, wherein the acrylic fiber comprises a polymer containing at least 93% by weight acrylonitrile.
Claim 4
Dependent Claim
28 words
A carbonaceous fiber as in claim 2, wherein the polymer comprises at least 95% by weight of acrylonitrile and from 1% to 5% by weight of methyl acrylate.
Claim 5
Dependent Claim
22 words
A carbonaceous fiber as in claim 2, wherein the polymer has a molecular weight of from 1×10 4 to 1×10 5 .
Claim 6
Dependent Claim
24 words
A carbonaceous fiber as in claim 2, wherein the individual filament of the acrylic fiber has a fineness of from 0.1 to 1.0 denier.
Claim 7
Dependent Claim
30 words
A carbonaceous fiber as in claim 1, wherein the acrylic fiber has a degree of orientation of not less than 85% at an angle of X-ray diffraction (2θ) of 17°.
Claim 8
Dependent Claim
20 words
A carbonaceous fiber as in claim 1, wherein the acrylic fiber composes a strand comprising from 100 to 100,000 filaments.
Claim 9
Dependent Claim
21 words
A carbonaceous fibers as in claim 1, wherein the preoxidation is conducted at a temperature of from 200° to 300° C.
Claim 10
Dependent Claim
21 words
A carbonaceous fibers as in claim 1, wherein the preoxidation is conducted under a tension of from 70 to 200 mg/denier.
Claim 11
Dependent Claim
30 words
A carbonaceous fiber as in claim 1, wherein the preoxidized fiber has a degree of orientation of not less than 80% at an angle of X-ray diffraction (2θ) of 25°.
Claim 12
Dependent Claim
21 words
A carbonaceous fiber as in claim 1, wherein the lowest temperature of the lower temperature zone is more than 280° C.
Claim 13
Dependent Claim
21 words
A carbonaceous fiber as in claim 1, wherein the pyrolysis is conducted under a tension of from 150 to 250 mg/denier.
Claim 14
Dependent Claim
21 words
A carbonaceous fiber as in claim 1, wherein the temperature of the lower temperature zone is from 300° to 550° C.
Claim 15
Dependent Claim
22 words
A carbonaceous fiber as in claim 1, wherein the fiber is treated at the lower temperature zone until necessary stretching is attained.
Claim 16
Dependent Claim
27 words
A carbonaceous fiber as in claim 1, wherein the temperature of the lower temperature zone is raised at a rate of from 1 to 50 per second.
Claim 17
Dependent Claim
23 words
A carbonaceous fiber as in claim 1, wherein the pyrolysis in the lower temperature zone is conducted for form 0.1 to 10 minutes.
Claim 18
Dependent Claim
23 words
A carbonaceous fiber as in claim 1, wherein the pyrolysis in the higher temperature zone is conducted for from 0.5 to 10 minutes.
Claim 19
Dependent Claim
34 words
A carbonaceous fiber as in claim 1, wherein the carbonaceous fiber has a tensile strength of at least 250 kg/mm 2 , and a modulus of elasticity of at least 15,000 kg/mm 2 .
Claim 20
Dependent Claim
31 words
A carbonaceous fiber as in claim 1, wherein the specific gravity of the preoxidized fiber is not less than 1.35 and the temperature of pyrolyzing is not higher than 900° C.
Claim 21
Dependent Claim
21 words
A carbonaceous fiber as in claim 19, wherein the moisture regaine of the carbonaceous fiber is at least 0.5% by weight.
Claim 22
Independent Claim
199 words
A method for producing carbon fiber which comprises preoxidizing an acrylic fiber in an oxidizing atmosphere at a temperature of from 10° to 60° C. below the decomposition point of said fiber to prepare a preoxidized fiber having a degree of orientation of not less than 78% at an angle of X-ray diffraction (2θ) of 25° and a specific gravity of from 1.30 to 1.40, pyrolyzing the preoxidized fiber in an inert gas atmosphere by passing the fiber firstly through a lower temperature zone having a temperature of not higher than 750° C., wherein the preoxidized fiber is stretched in the lower temperature zone to an extent of from 40 to 75% of the maximum draw ratio of the fiber at the temperature of said zone, and then through a higher temperature zone having a temperature of from 750° to 950° C., and during the pyrolysis controlling the tension of the fiber so that the change of the fiber length during pyrolyzing is from +16% to -8.8% based on the length of the preoxidized fiber, wherein the fiber is shrunk to an extent of from 40 to 80% of the free shrinkage during pyrolyzing in the higher temperature zone.
Claim 23
Independent Claim
199 words
A method for producing carbon fiber which comprises preoxidizing an acrylic fiber in an oxidizing atmosphere at a temperature of from 10° to 60° C. below the decomposition point of said fiber to prepare a preoxidized fiber having a degree of orientation of not less than 78% at an angle of X-ray diffraction (2θ) of 25° and a specific gravity of from 1.30 to 1.40, pyrolyzing the preoxidized fiber in an inert gas atmosphere by passing the fiber firstly through a lower temperature zone having a temperature of not higher than 750° C., wherein the preoxidized fiber is stretched in the lower temperature zone to an extent of from 40 to 75% of the maximum draw ratio of the fiber at the temperature of said zone, and then through a higher temperature zone having a temperature of from 750° to 950° C., and during the pyrolysis controlling the tension of the fiber so that the change of the fiber length during pyrolyzing is from +16% to -8.8% based on the length of the preoxidized fiber, wherein the fiber is shrunk to an extent of from 40 to 80% of the free shrinkage during pyrolyzing in the higher temperature zone.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-06-08 | 1990-12-08 | 1991-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-08 | 1994-12-08 | 1995-06-09 | $3760.00 | Window Closed / Lapsed |
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