US4113847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing carbon fibers
Assignee: Sumika Hercules Co Ltd
•
Filing: 1976-09-01
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Granted: 1978-09-12
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Expires: 1996-09-01
Abstract
Abstract Carbon fibers are prepared by spinning a copolymer of a carboxyl group-containing unsaturated monomer and at least 85 mol% acrylonitrile, washing the filaments with water, stretching the filaments in hot acid water having a pH below 3.5, and heating the resultant fibers to cause carbonization or graphitization.
Inventors
- 👤 Keitaro Fukushima
- 👤 Takamaro Kusunose
- 👤 Yoshinori Nosaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:12
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
64 words
A process for producing carbon fibers, which comprises spinning a copolymer containing at least 85 mol % acrylonitrile and a carboxyl group-containing unsaturated monomer into filaments, washing the filaments with water, stretching the washed filaments in water above 80° C. maintained at a pH below 3.5, drying the stretched filaments thermally stabilizing the dried filaments, and carbonizing, or carbonizing and graphitizing, the stabilized filaments.
Claim 2
Dependent Claim
64 words
A process for producing carbon fibers, which comprises spinning a copolymer containing at least 85 mol % acrylonitrile and a carboxyl group-containing unsaturated monomer into filaments, washing the filaments with water, stretching the washed filaments in water above 80° C. maintained at a pH below 3.5, drying the stretched filaments thermally stabilizing the dried filaments, and carbonizing, or carbonizing and graphitizing, the stabilized filaments.
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 wherein, after the stretching, the filaments are subjected to steam stretching and drying.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 1 wherein the copolymer contains at least 90 mol % of acrylonitrile.
Claim 5
Dependent Claim
20 words
A process as claimed in claim 1 wherein the copolymer contains 0.1-10 mol % of the carboxyl group-containing unsaturated monomer.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 1 wherein the copolymer contains 0.5-5 mol % of the carboxyl group-containing unsaturated monomer.
Claim 7
Dependent Claim
22 words
A process as claimed in claim 1 wherein the stretching is conducted in water maintained at a pH not higher than 3.0.
Claim 8
Dependent Claim
22 words
A process as claimed in claim 1 wherein the stretching is conducted in water at a temperature not lower than 90° C.
Claim 9
Dependent Claim
19 words
A process as claimed in claim 1 wherein the stretching is conducted at a stretch ratio of 2-8 times.
Claim 10
Dependent Claim
32 words
A process as claimed in claim 2 wherein the steam stretching is conducted at a temperature not lower than 110° C. and at a stretch ratio of not lower than 1.2 times.
Claim 11
Dependent Claim
53 words
A process as claimed in claim 1 wherein the dried filaments are thermally stabilized by heating the filaments in an oxidizing atmosphere at a temperature of from 150° C. to 400° C., and the stabilized filaments are carbonized, or carbonized and then graphitized, in a non-oxidizing atmosphere at a temperature above 800° C.
Claim 12
Dependent Claim
15 words
A process as claimed in claim 10 wherein the filaments are thermally stabilized under tension.
Claim 13
Dependent Claim
20 words
A process as claimed in claim 10 wherein the stabilized filaments are carbonized, or carbonized and then graphitized, under tension.
Claim 14
Dependent Claim
13 words
A process as claimed in claim 10 wherein the oxidizing atmosphere is air.
Claim 15
Dependent Claim
44 words
A process as claimed in claim 10 wherein the stabilized filaments are carbonized in a non-oxidizing atmosphere at a temperature of from 800° C. to 2000° C. and then graphitized in a non-oxidizing atmosphere at a temperature of from 2000° C. to 3500° C.
Claim 16
Dependent Claim
13 words
A process as claimed in claim 10 wherein the non-oxidizing atmosphere is nitrogen.
References Cited (Backward Citations)
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US4002426A
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US3733386A
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US3886263A
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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) | 1981-09-11 | 1982-03-13 | 1982-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-11 | 1986-03-13 | 1986-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-11 | 1990-03-13 | 1990-09-12 | $7700.00 | Window Closed / Lapsed |