Patent US4070446A successfully refreshed from Google Patents.
US4070446A
Expired / Lapsed
US
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Process for production of carbon fiber
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1974-02-01
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Granted: 1978-01-24
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Expires: 1994-02-01
Abstract
Abstract A process for the production of carbon fiber, which comprises sulfonating polyethylene fiber with chlorosulfonic acid, sulfuric acid, fuming sulfuric acid or a mixture of two or more kinds thereof and carbonizing the resulting precursor fiber by heating at a temperature of 600° to 3,000° C, optionally while giving a tension to the fiber.
Inventors
- 👤 Shozo Horikiri
- 👤 Jiro Iseki
- 👤 Masao Minobe
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; D01F9/20; D01F9/21; Y; Y10; Y10S; Y10S264/00; Y10S264/19
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
77 words
A process for producing carbon fiber, which comprises sulfonating fiber consisting of polyethylene or a copolymer of ethylene containing 90 or more % by weight of ethylene units with a sulfonating agent selected from the group consisting of chlorosulfonic acid, sulfuric acid, fuming sulfuric acid and mixtures thereof and then carbonizing the resultant sulfonated product by heating at a temperature of from 600° to 2,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 2
Dependent Claim
77 words
A process for producing carbon fiber, which comprises sulfonating fiber consisting of polyethylene or a copolymer of ethylene containing 90 or more % by weight of ethylene units with a sulfonating agent selected from the group consisting of chlorosulfonic acid, sulfuric acid, fuming sulfuric acid and mixtures thereof and then carbonizing the resultant sulfonated product by heating at a temperature of from 600° to 2,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 3
Dependent Claim
30 words
The process according to claim 1, wherein the polyethylene fiber comprises polyethylene having a density of 0.94 or more g/cm 3 and a melt index of from 0.1 to 10.
Claim 4
Dependent Claim
77 words
A process for producing graphite fiber, which comprises sulfonating fiber consisting of polyethylene or a copolymer of ethylene containing 90 or more % by weight of ethylene units with a sulfonating agent selected from the group consisting of chlorosulfonic acid, sulfuric acid, fuming sulfuric acid and mixtures thereof and then carbonizing the resultant sulfonated product by heating at a temperature of from 2,000° to 3,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 5
Dependent Claim
77 words
A process for producing graphite fiber, which comprises sulfonating fiber consisting of polyethylene or a copolymer of ethylene containing 90 or more % by weight of ethylene units with a sulfonating agent selected from the group consisting of chlorosulfonic acid, sulfuric acid, fuming sulfuric acid and mixtures thereof and then carbonizing the resultant sulfonated product by heating at a temperature of from 2,000° to 3,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 6
Dependent Claim
30 words
The process according to claim 3, wherein the polyethylene fiber comprises polyethylene having a density of 0.94 or more g/cm 3 and a melt index of from 0.1 to 10.
Claim 7
Dependent Claim
25 words
The process according to claim 1, wherein the sulfonation is carried out by using chlorosulfonic acid at a temperature of from 60° to 90° C.
Claim 8
Dependent Claim
25 words
The process according to claim 3, wherein the sulfonation is carried out by using chlorosulfonic acid at a temperature of from 60° to 90° C.
Claim 9
Dependent Claim
27 words
The process according to claim 1, wherein the sulfonation is caried out by using chlorosulfonic acid which contains 30 or less % by volume of sulfuric acid.
Claim 10
Dependent Claim
27 words
The process according to claim 3, wherein the sulfonation is carried out by using chlorosulfuric acid which contains 30 or less % by volume of sulfuric acid.
Claim 11
Dependent Claim
26 words
The process according to claim 1, wherein the sulfonation is carried out by using sulfuric acid having a concentration of 90 or more % by weight.
Claim 12
Dependent Claim
26 words
The process according to claim 3, wherein the sulfonation is carried out by using sulfuric acid having a concentration of 90 or more % by weight.
Claim 13
Dependent Claim
21 words
The process according to claim 9, wherein the sulfonation is carried out at a temperature of from 100° to 180° C.
Claim 14
Dependent Claim
21 words
The process according to claim 10, wherein the sulfonation is carried out at a temperature of from 100° to 180° C.
Claim 15
Dependent Claim
30 words
The process according to claim 1, wherein the sulfonation is carried out by using fuming sulfuric acid containing sulfuric anhydride in a concentration of 50 or less % by weight.
Claim 16
Dependent Claim
30 words
The process according to claim 3, wherein the sulfonation is carried out by using fuming sulfuric acid containing sulfuric anhydride in a concentration of 50 or less % by weight.
Claim 17
Dependent Claim
15 words
The process according to claim 1, wherein said inert gas is nitrogen, helium or argon.
Claim 18
Dependent Claim
15 words
The process according to claim 3, wherein said inert gas is nitrogen, helium or argon.
Claim 19
Dependent Claim
29 words
The process according to claim 1, wherein the sulfonation and carbonization steps are carried out while the polyethylene fiber is under a tension of from 20 to 200 mg/d.
Claim 20
Dependent Claim
29 words
The process according to claim 3, wherein the sulfonation and carbonization steps are carried out while the polyethylene fiber is under a tension of from 20 to 200 mg/d.
Claim 21
Dependent Claim
58 words
A carbon fiber, which is produced by sulfonating fiber consisting of polyethylene with a member selected from the group consisting of chlorosulfonic acid, sulfuric acid and fuming sulfuric acid and then carbonizing the resultant sulfonated product by heating at a temperature of from 600° to 2,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 22
Dependent Claim
58 words
A carbon fiber, which is produced by sulfonating fiber consisting of polyethylene with a member selected from the group consisting of chlorosulfonic acid, sulfuric acid and fuming sulfuric acid and then carbonizing the resultant sulfonated product by heating at a temperature of from 600° to 2,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 23
Dependent Claim
58 words
A graphite fiber, which is prooduced by sulfonating fiber consisting of polyethylene with a member selected from the group consisting of chlorosulfonic acid, sulfuric acid and fuming sulfuric acid and then carbonizing the resultant sulfonated product by heating at a temperature of from 2,000° to 3,000° C. in an atmosphere of an inert gas or in a vacuum.
Claim 24
Dependent Claim
58 words
A graphite fiber, which is prooduced by sulfonating fiber consisting of polyethylene with a member selected from the group consisting of chlorosulfonic acid, sulfuric acid and fuming sulfuric acid and then carbonizing the resultant sulfonated product by heating at a temperature of from 2,000° to 3,000° C. in an atmosphere of an inert gas or in a vacuum.
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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) | 1981-01-23 | 1981-07-25 | 1982-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-23 | 1985-07-25 | 1986-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-23 | 1989-07-25 | 1990-01-24 | $7700.00 | Window Closed / Lapsed |