US4080417A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing carbon fibers having excellent properties
Assignee: Sumika Hercules Co Ltd
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Filing: 1976-09-08
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Granted: 1978-03-21
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Expires: 1996-09-08
Abstract
Abstract A process for producing carbon fibers by heat-treating an acrylonitrile fiber, containing or impreganted with an aminosiloxane, at a temperature of at least 150° C for 0.1 second to 30 minutes so that the fiber contains 20 to 80 weight % undissolved matter upon immersing it in a 60% aqueous solution of sodium thiocyanate at 80° C for 20 minutes, and then carbonizing the fiber, whereby the productivity throughout the whole process, including the step of producing the precursor fiber and the step of producing the carbon fiber, is increased and a carbon fiber having high tensile strength and high modulus of elasticity is obtained in an industrially advantageous manner.
Inventors
- 👤 Soichiro Kishimoto
- 👤 Saburo Okazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:27
CPC Classifications
C; C08; C08K; C08K7/00; C08K7/02; C08K7/04; C08K7/06; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
186 words
A process for producing carbon fibers which comprises (1) heat-treating an acrylonitrile fiber impregnated with or containing at least 0.01%, based on the total weight of the fiber, of an aminosiloxane at a temperature of at least 150° C for 0.1 second to 30 minutes such that the heat-treated fiber contains 20 to 80 weight percent of undissolved matter, measured on the basis of immersion of the heat-treated fiber in a 60% aqueous solution of sodium thiocyanate at 80° C for 20 minutes, and (2) carbonizing or graphitizing the heat-treated fiber, said aminosiloxane having the formula ##STR4## wherein R 1 is hydrogen, lower alkyl or aryl, R 2 and R 3 are each lower alkyl or aryl, R 4 is hydrogen or a ##STR5## group wherein R 7 and R 8 are each lower alkyl and R 9 is hydrogen or lower alkyl, R 5 and R 6 are each hydrogen or lower alkyl, A is alkylene containing not more than 5 carbon atoms or arylene, and x and y are positive integers which impart a molecular weight of not more than 100,000 to the aminosiloxane.
Claim 2
Dependent Claim
186 words
A process for producing carbon fibers which comprises (1) heat-treating an acrylonitrile fiber impregnated with or containing at least 0.01%, based on the total weight of the fiber, of an aminosiloxane at a temperature of at least 150° C for 0.1 second to 30 minutes such that the heat-treated fiber contains 20 to 80 weight percent of undissolved matter, measured on the basis of immersion of the heat-treated fiber in a 60% aqueous solution of sodium thiocyanate at 80° C for 20 minutes, and (2) carbonizing or graphitizing the heat-treated fiber, said aminosiloxane having the formula ##STR4## wherein R 1 is hydrogen, lower alkyl or aryl, R 2 and R 3 are each lower alkyl or aryl, R 4 is hydrogen or a ##STR5## group wherein R 7 and R 8 are each lower alkyl and R 9 is hydrogen or lower alkyl, R 5 and R 6 are each hydrogen or lower alkyl, A is alkylene containing not more than 5 carbon atoms or arylene, and x and y are positive integers which impart a molecular weight of not more than 100,000 to the aminosiloxane.
Claim 3
Dependent Claim
19 words
A process as claimed in claim 1 wherein the acrylonitrile fiber contains at least 90 mol % of acrylonitrile.
Claim 4
Dependent Claim
24 words
A process as claimed in claim 1 wherein the acrylonitrile fiber is impregnated with or contains 0.05 - 5% by weight of the aminosiloxane.
Claim 5
Dependent Claim
21 words
A process as claimed in claim 1 wheren the heat-treatment of the acrylonitrile fiber is conducted at 160° - 550° C.
Claim 6
Dependent Claim
22 words
A process as claimed in claim 1 wherein the heat-treatment of the acrylonitrile fiber is conducted for 0.2 second - 20 minutes.
Claim 7
Dependent Claim
27 words
A process as claimed in claim 1 wherein the heat-treatment is conducted under such temperature and time conditions as defined by the shade area in FIG. 1.
Claim 8
Dependent Claim
51 words
A process as claimed in claim 1 wherein the heat-treated acrylonitrile fiber is thermally stabilized by being heated in an oxidizing atmosphere at a temperature of from 150° C. to 400° C., and is thereafter carbonized or carbonized and then graphitized in a non-oxidizing atmosphere at a temperature above 800° C.
Claim 9
Dependent Claim
19 words
A process claimed in claim 7 wherein the heat-treated acrylonitrile fiber is thermally stabilized while being heated under tension.
Claim 10
Dependent Claim
13 words
A process as claimed in claim 8 wherein the tension is 0.1-0.5 g/d.
Claim 11
Dependent Claim
21 words
A process as claimed in claim 7 wherein the thermally stabilized fibers are carbonized or carbonized and then graphitized under tension.
Claim 12
Dependent Claim
13 words
A process as claimed in claim 1 wherein the tension is 0.1-0.5 g/d.
Claim 13
Dependent Claim
13 words
A process as claimed in claim 7 wherein the oxidizing atmosphere is air.
Claim 14
Dependent Claim
45 words
A process as claimed in claim 7 wherein the thermally stabilized fibers 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 15
Dependent Claim
13 words
A process as claimed in claim 7 wherein the nonoxidizing atmosphere is nitrogen.
Claim 16
Dependent Claim
19 words
A process as claimed in claim 1 wherein the acrylonitrile fiber contains at least 85 mol % of acrylonitrile.
Claim 17
Dependent Claim
31 words
A process as claimed in claim 1 wherein the acrylonitrile fiber subjected to heat-treatment is prepared by adding the aminosiloxane to an acrylonitrile fiber-producing spinning solution, and spinning the spinning solution.
Claim 18
Dependent Claim
38 words
A process as claimed in claim 1 wherein the acrylonitrile fiber subjected to heat-treatment is prepared by spinning an acrylonitrile fiber-producing spinning solution to obtain a water-swollen acrylonitrile fiber, and impregnating the water-swollen acrylonitrile fiber with the aminosiloxane.
Claim 19
Dependent Claim
28 words
A process as claimed in claim 1 wherein the water content in the water-swollen acrylonitrile fiber is 20 - 200% based on the dry weight of the fiber.
Claim 20
Dependent Claim
28 words
A process as claimed in claim 1 wherein the molecular weight of the aminosiloxane is 2000 - 100,000 and the ratio of x:y in the aminosiloxane is 4-200:1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |