Patent US3288639A successfully refreshed from Google Patents.
Patent US3720759A successfully refreshed from Google Patents.
US3720759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of carbon and graphite fibers
Assignee: Sigri Elektrographit dt GmbH
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Filing: 1970-05-21
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Granted: 1973-03-13
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Expires: 1990-05-21
Abstract
Abstract Carbon fibers are produced by treating synthetic polymeric fibers with a solution of a condensation agent at a temperature of 180* to 230*C to effect cross-linking and/or cyclization within the polymeric fibers and thereafter heating the treated fibers to a temperature between 200*-300*C in an atmosphere containing an oxidizing gas and, subsequently, in an inert or reducing atmosphere, to a temperature of at least about 1,000*C. Titanium tetrachloride, lead tetrachloride, tin tetrachloride, and tin tetrabromide are used as condensation agents, preferably in the form of complexes in a solvent such as high-boiling ethers and esters. Dimethylformamide is used as a complex former. onitroanisole, d-n-butylterephthalate, and iso-octadecylbenzoate are used as both solvent and complex former.
Inventors
- 👤 D Overhoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:57
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; Y; Y10; Y10S; Y10S264/00; Y10S264/19
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
Method of producing a carbonaceous fiber from a thermoplastic polymeric fiber selected from polyacrylonitrile and polyacrylonitrile copolymers, comprising the steps of: a. stretching or elongating the polymeric fiber to a stretching ratio of at least 1:4 until the tensile strength of the stretched fiber is at least 4 p/den; b. heating the fiber in a solution of a solvent selected from o-nitroanisole, di-n-butylterephthalate or i-octadecylbenzoate containing a complex of said solvent and a halide selected from the group consisting of titanium tetrachloride, lead tetrachloride, tin tetrachloride and tin tetrabromide, to a temperature of 180 to 230*C; and c. heating the fiber without external tensile stress to a temperature between 200* and 300*C in an atmosphere containing oxidizing gases and, subsequently, in an inert or reducing atmosphere, to approximately 1,000*C.
Claim 2
Dependent Claim
129 words
Method of producing a carbonaceous fiber from a thermoplastic polymeric fiber selected from polyacrylonitrile and polyacrylonitrile copolymers, comprising the steps of: a. stretching or elongating the polymeric fiber to a stretching ratio of at least 1:4 until the tensile strength of the stretched fiber is at least 4 p/den; b. heating the fiber in a solution of a solvent selected from o-nitroanisole, di-n-butylterephthalate or i-octadecylbenzoate containing a complex of said solvent and a halide selected from the group consisting of titanium tetrachloride, lead tetrachloride, tin tetrachloride and tin tetrabromide, to a temperature of 180 to 230*C; and c. heating the fiber without external tensile stress to a temperature between 200* and 300*C in an atmosphere containing oxidizing gases and, subsequently, in an inert or reducing atmosphere, to approximately 1,000*C.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein di-n-butylterephthalate is used as both complexing agent and solvent for lead tetrachloride.
Claim 4
Dependent Claim
18 words
The method of claim 1, wherein iso-octadecylbenzoate is used as both complexing agent and solvent for tin tetrabromide.
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein the solution contains at least 0.8 percent by weight of a complex of said halide.
Claim 6
Dependent Claim
22 words
The method of claim 4, wherein the solution contains from 1.0 to 1.5 percent by weight of a complex of said halide.
Claim 7
Dependent Claim
17 words
The method of claim 1, wherein the synthetic polymeric fiber is a copolymer of acrylonitrile and methylmethacrylate.
References Cited (Backward Citations)
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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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |