Patent US3846833A successfully refreshed from Google Patents.
US3846833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acrylic filaments which are particularly suited for thermal conversion to carbon filaments
Assignee: Celanese Corp
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Filing: 1972-04-17
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Granted: 1974-11-05
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Expires: 1992-04-17
Abstract
Abstract Improved acrylic filaments are provided having an internal structure capable of yielding improved carbon filaments upon thermal conversion. The acrylilc filaments of the present invention are formed by a specifically defined wet spinning process which produces filaments having a highly fibrillar and dense internal structure. Upon thermal stabilization and subsequent thermal treatment at 1,000* to 2,000*C. a highly developed microporous structure is inherently imparted to the resulting carbon filaments wherein a large number of elongated micropores are disposed between a highly fibrillar internal structure. The resulting carbon filaments have an internal structure capable of increasing the amount of work required to break the same via crack diversion during fracture. Satisfactory strength properties are exhibited even if the internal structure of the improved carbon filaments is accompanied by the presence of gross inhomogenities and structural flaws, such as commonly encountered in carbon filaments of the prior art.
Inventors
- 👤 M Ram
- 👤 J Riggs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:17
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01F9/225; D01F6/00; D01F6/02; D01F6/18; D01F6/28; D01F6/38; D01F9/32; D01F9/328
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
257 words
AN IMPROVED ACRYLIC FILAMENT WHICH IS PARTICULARLY SUITED FOR THERMAL CONVERSION TO A CARBON FILAMENT FORMED IN ACCORDANCE WITH THE PROCESS COMPRISING: A. PROVIDING A SPINNING SOLUTION HAVING A LOW SHEAR VISCOSITY OF ABOUT 125 TO 1,500 POISE MEASURED AT 25*C. COMPRISING (1) A FIBER-FORMING ACRYLIC POLYMER IN A CONCENTRATION OF ABOUT 18 TO 25 PERCENT BY WEIGHT BASED UPON THE TOTAL WEIGHT OF THE SOLUTION SELECTED FROM THE GROUP CONSISTING OF AN ACRYLONITRILE HOMOPOLYMER AND AN ACRYLONITRILE COPOLYMER WHICH CONTAINS AT LEAST ABOUT 85 MOL PERCENT OF ACRYLONITRILE UNITS AND UP TO ABOUT 15 MOL PERCENT OF ONE OR MORE MONOVINYL UNITS COPOLYMERIZED THEREWITH, (2) LITHIUM CHLORIDE IN A CONCENTRATION OF ABOUT 0.1 TO 5 PERCENT BY WEIGHT BASED UPON THE TOTAL WEIGHT OF THE SOLUTION WHICH LOWERS AND PRESERVES UPON STANDING THE VISCOSITY OF THE SOLUTION, AND (3) A DIMETHYLACETAMIDE SOLVENT, B. EXTRUDING SAID SPINNING SOLUTION INTO AN ESSENTIALLY NONAQUEOUS COAGULATION BATH HAVING A TEMPERATURE OF ABOUT 10* TO 35*C. CONSISTING ESSENTIALLY OF ABOUT 55 TO 85 PERCENT BY WEIGHT OF ETHYLENE GLYCOL AND ABOUT 15 TO 45 PERCENT BY WEIGHT OF DIMETHYLACETAMIDE TO FORM AN ASSPUN FILAMENT WHICH IS PRESENT IN SAID COAGULATION BATH FOR A RESIDENCE TIME OF ABOUT 6 TO 300 SECONDS, C. WASHING THE RESULTING AS-SPUN FILAMENT IN WATER TO REMOVE DIMETHYLACETAMIDE AND LITHIUM CHLORIDE FROM THE SAME, THE SAID WASHING BEING INITIALLY CONDUCTED FOR AT LEAST 25 SECONDS WITH SAID WATER AT A TEMPERATURE OF ABOUT 10* TO 50*C., AND D. DRAWING SAID WASHED FILAMENT TO INCREASE THE ORIENTATION THEREOF.
Claim 2
Dependent Claim
257 words
AN IMPROVED ACRYLIC FILAMENT WHICH IS PARTICULARLY SUITED FOR THERMAL CONVERSION TO A CARBON FILAMENT FORMED IN ACCORDANCE WITH THE PROCESS COMPRISING: A. PROVIDING A SPINNING SOLUTION HAVING A LOW SHEAR VISCOSITY OF ABOUT 125 TO 1,500 POISE MEASURED AT 25*C. COMPRISING (1) A FIBER-FORMING ACRYLIC POLYMER IN A CONCENTRATION OF ABOUT 18 TO 25 PERCENT BY WEIGHT BASED UPON THE TOTAL WEIGHT OF THE SOLUTION SELECTED FROM THE GROUP CONSISTING OF AN ACRYLONITRILE HOMOPOLYMER AND AN ACRYLONITRILE COPOLYMER WHICH CONTAINS AT LEAST ABOUT 85 MOL PERCENT OF ACRYLONITRILE UNITS AND UP TO ABOUT 15 MOL PERCENT OF ONE OR MORE MONOVINYL UNITS COPOLYMERIZED THEREWITH, (2) LITHIUM CHLORIDE IN A CONCENTRATION OF ABOUT 0.1 TO 5 PERCENT BY WEIGHT BASED UPON THE TOTAL WEIGHT OF THE SOLUTION WHICH LOWERS AND PRESERVES UPON STANDING THE VISCOSITY OF THE SOLUTION, AND (3) A DIMETHYLACETAMIDE SOLVENT, B. EXTRUDING SAID SPINNING SOLUTION INTO AN ESSENTIALLY NONAQUEOUS COAGULATION BATH HAVING A TEMPERATURE OF ABOUT 10* TO 35*C. CONSISTING ESSENTIALLY OF ABOUT 55 TO 85 PERCENT BY WEIGHT OF ETHYLENE GLYCOL AND ABOUT 15 TO 45 PERCENT BY WEIGHT OF DIMETHYLACETAMIDE TO FORM AN ASSPUN FILAMENT WHICH IS PRESENT IN SAID COAGULATION BATH FOR A RESIDENCE TIME OF ABOUT 6 TO 300 SECONDS, C. WASHING THE RESULTING AS-SPUN FILAMENT IN WATER TO REMOVE DIMETHYLACETAMIDE AND LITHIUM CHLORIDE FROM THE SAME, THE SAID WASHING BEING INITIALLY CONDUCTED FOR AT LEAST 25 SECONDS WITH SAID WATER AT A TEMPERATURE OF ABOUT 10* TO 50*C., AND D. DRAWING SAID WASHED FILAMENT TO INCREASE THE ORIENTATION THEREOF.
Claim 3
Dependent Claim
34 words
An improved acrylic filament which is particularly suited for thermal conversion to a carbon filament formed in accordance with the process described in claim 1 wherein said fiber-forming acrylic polymer is an acrylonitrile homopolymer.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |