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US4347279A
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High performance carbon fiber, process for production thereof, and composite materials prepared therewith
Assignee: Teijin Ltd
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Filing: 1981-08-21
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Granted: 1982-08-31
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Expires: 2001-08-21
Abstract
Abstract A carbon fiber, a process for production thereof, and composite materials prepared therewith are described, wherein the carbon fiber has a single yarn diameter of from 2 to 6 microns and showing a strand knot strength of 7 kilograms or more when formed into a strand of 0.4±0.01 gram per meter, which comprises subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a strength of 6 grams per denier or more to a preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5%, and (b) a second preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of from 240° C. to 300° C. while maintaining the relation between the preoxidation treatment time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (1): (310-T)×(0.8˜3)=t (I) and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at from 1,000° C. to 1,800° C.
Inventors
- 👤 Yasuo Saji
- 👤 Kozo Tanaka
- 👤 Takashi Yamauchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:46
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01F9/225; D01F9/32; Y; Y10; Y10S; Y10S428/00; Y10S428/902; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249924; Y10T428/249928; Y10T428/24994; Y10T428/249942; Y10T428/249945; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/298; Y10T428/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
185 words
A process for producing a carbon fiber having a single yarn diameter of from 2 to 6 microns and showing a strand knot strength of at least 7 kilograms when formed into a strand of 0.4±0.01 gram per meter, said process comprising: subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a tensile strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) a first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5%, and (b) a second preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of from 240° C. to 300° C. while maintaining the relation between the preoxidation time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I) and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at from 1,000° C. to 1,800° C.
Claim 2
Dependent Claim
185 words
A process for producing a carbon fiber having a single yarn diameter of from 2 to 6 microns and showing a strand knot strength of at least 7 kilograms when formed into a strand of 0.4±0.01 gram per meter, said process comprising: subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a tensile strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) a first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5%, and (b) a second preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of from 240° C. to 300° C. while maintaining the relation between the preoxidation time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I) and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at from 1,000° C. to 1,800° C.
Claim 3
Dependent Claim
64 words
A process as in claim 1, wherein the preoxidation treatment is performed in a number of stages "n", and when the preoxidation treatment is performed at T 1 °C. for t 1 minutes, at T 2 °C. for t 2 minutes, . . . at T n °C. for t n minutes, T is determined as follows: ##EQU4## wherein n is at least 2.
Claim 4
Dependent Claim
19 words
A process as in claim 1, wherein the shrinkage during the first preoxidation treatment is from 3% to 20%.
Claim 5
Dependent Claim
19 words
A process as in claim 1, wherein the shrinkage at the second preoxidation treatment is from 1% to 20%.
Claim 6
Dependent Claim
22 words
A process as claimed in claim 1, wherein the total of the shrinkage at the preoxidation treatment is from 4% to 30%.
Claim 7
Dependent Claim
23 words
A process as in claim 1, wherein the second preoxidation treatment is performed until the equilibrium water content reaches from 9% to 12%.
Claim 8
Dependent Claim
63 words
A process as claimed in claim 1, wherein the second preoxidation treatment is divided into the first half and the second half steps, and the preoxidation is conducted while providing a predetermined shrinkage at the first half step and a finishing treatment is applied for from 30 seconds to 20 minutes at a constant length of the fiber at the second half step.
Claim 9
Dependent Claim
180 words
A carbon fiber having a single yarn diameter of from 2 to 6 microns and showing a strand knot strength of at least 7 kilograms when formed into a strand of 0.4±0.01 gram per meter, which is produced by subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5%, and (b) a second preoxidation treatment wherein the acrylonitrile based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of 240° C. to 3000° C. while maintaining the relation between the preoxidation time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I) and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at from 1,000° C. to 1,800° C.
Claim 10
Dependent Claim
180 words
A carbon fiber having a single yarn diameter of from 2 to 6 microns and showing a strand knot strength of at least 7 kilograms when formed into a strand of 0.4±0.01 gram per meter, which is produced by subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5%, and (b) a second preoxidation treatment wherein the acrylonitrile based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of 240° C. to 3000° C. while maintaining the relation between the preoxidation time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I) and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at from 1,000° C. to 1,800° C.
Claim 11
Dependent Claim
189 words
A composite material containing as a reinforcing material a carbon fiber having a single yarn diameter of from 2 to 6 mincrons and showing a strand knot strength of at least 7 kilograms when formed into a stand of 0.4±0.01 gram per meter, which is produced by subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a tensile strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) a first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5% and (b) a second preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of from 240° C. to 300° C. while maintaining the relation between the preoxidation treatment time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I), and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at 1,000° to 1,800° C.
Claim 12
Dependent Claim
189 words
A composite material containing as a reinforcing material a carbon fiber having a single yarn diameter of from 2 to 6 mincrons and showing a strand knot strength of at least 7 kilograms when formed into a stand of 0.4±0.01 gram per meter, which is produced by subjecting a 0.1 to 0.6 denier acrylonitrile-based fiber having a tensile strength of at least 6 grams per denier to a preoxidation treatment consisting of (a) a first preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 3% until the equilibrium water content reaches 5% and (b) a second preoxidation treatment wherein the acrylonitrile-based fiber is treated under such tension as to provide a shrinkage of at least 1%, said preoxidation treatment is conducted in an oxidizing atmosphere having a temperature of from 240° C. to 300° C. while maintaining the relation between the preoxidation treatment time (t) (minutes) and average preoxidation treatment temperature (T) (°C.) satisfying the equation (I): (310-T)×(0.8˜3)=t (I), and subjecting the thus preoxidized fiber to a carbonization treatment in an inert gas maintained at 1,000° to 1,800° C.
Claim 13
Dependent Claim
23 words
A composite material as in claim 9, wherein the matrix of the composite material is a thermosetting resin, a thermoplastic resin, or carbon.
Claim 14
Dependent Claim
29 words
A composite material as in claim 10 wherein the matrix is a thermosetting resin selected from a furan resin, a phenol resin, a polyimide resin, or an epoxy resin.
Claim 15
Dependent Claim
24 words
A composite material as in claim 10 wherein the matrix is a thermoplastic resin selected from polyolefin, nylon, polyvinyl choride, polyvinylidene chloride, or polyester.
Claim 16
Dependent Claim
24 words
A composite material as claimed in claim 9, 10, 11, or 12, wherein the carbon fiber content is from 20% to 80% by volume.
References Cited (Backward Citations)
US4100004A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-30 | 1986-03-01 | 1986-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-30 | 1990-03-01 | 1990-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-30 | 1994-03-01 | 1994-08-31 | $7700.00 | Window Closed / Lapsed |