US3635675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of graphite yarns
Assignee: United States Department of the Air Force
•
Filing: 1968-05-28
•
Granted: 1972-01-18
•
Expires: 1988-05-28
Abstract
Abstract A method of making graphite fibers with high-tensile strength, high modulus of elasticity and, in many instances, fibers of improved graphitic character is described. The method of producing such fibers, generally in the form of yarn, comprises rapidly bringing a stabilized synthetic polymer yarn to a temperature within the range of 1800*-3200* C. Stabilization of the synthetic polymer yarn, when necessary, is usually effected by heating the yearn at a selected temperature in the range of about 200*-500* C. in an oxidizing atmosphere. Among the preferred polymers are the acrylonitrile polymers and polymers of nitrogen-containing polycylic organic compounds.
Inventors
- 👤 Herbert M Ezekiel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:30
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01F9/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
27 words
The process of claim 1 in which said polymer is an acrylonitrile polymer having at least 50 percent by weight of acrylonitrile in the polymer molecUles thereof.
Claim 2
Dependent Claim
36 words
The method according to claim 1 wherein the said synthetic polymer fibers are comprised of acrylonitrile polymers, and the acrylonitrile polymers are stabilized by heating in the range of 265*-290* C., for at least 3 hours.
Claim 3
Dependent Claim
16 words
The method of claim 3 wherein said heating is at about 275* C. for 3-7 hours.
Claim 4
Dependent Claim
21 words
The method according to claim 1 wherein said polymer fibers are in the form of a yarn and are under tension.
Claim 5
Dependent Claim
17 words
The method according to claim 1 wherein said graphitization heating is carried out for about 0.5-2 minutes.
Claim 6
Dependent Claim
32 words
The method according to claim 1 wherein said polymer fibers are in the form of yarn, said yarn is under tension, and said graphitization heating is carried out for about 0.25-2 minutes.
Claim 7
Dependent Claim
26 words
The method according to claim 1 wherein said polymer is an acrylonitrile copolymer containing at least 85 percent by weight of acrylonitrile in the polymer molecule.
Claim 8
Dependent Claim
13 words
The method according to claim 1 wherein said polymer is an acrylonitrile homopolymer.
Claim 9
Dependent Claim
27 words
The method according to claim 1 wherein said polymer is a copolymer of approximately 97 percent by weight acrylonitrile and 3 percent by weight of vinyl acetate.
Claim 10
Dependent Claim
21 words
The method according to claim 1 wherein said polymer is an acrylonitrile copolymer containing at least 65 percent by weight acrylonitrile.
Claim 11
Dependent Claim
11 words
The method according to claim 1 wherein said polymer is poly(2,2''-(m-phenylene)-5,5''-(dibenzimidazole)).
Claim 12
Dependent Claim
11 words
The method according to claim 1 wherein said polymer is poly(bisbenzimidazobenzophenanthroline).
References Cited (Backward Citations)
US3094511A
Cited
US3285696A
Cited
US3412062A
Cited
US3399252A
Cited
US3449077A
Cited
US3528774A
Cited
US3540848A
Cited
US3547584A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |