US3681023A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of carbon fibers
Assignee: Asahi Kasei Corp
•
Filing: 1969-12-15
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Granted: 1972-08-01
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Expires: 1989-12-15
Abstract
Abstract CARBON FIBER HAVING A HIGH TENSILE STRENGTH AND A HIGH VALUE OF YOUNG''S MODULUS IS PRODUCED BY HEATING, TO A SUBSTANTIALLY CARBONIZED STATE STRETCHED POLYACRYLONITRILE FIBER PREPARED FROM POLYACRYLONITRILE WHICH HAS BEEN PRODUCED BY THE SOLID STATE RADIATION POLYMERIZATION OF ACRYLONITRILE AT A TEMPERATURE NOT HIGHER THAN THE MELTING POINT OF ACRYLONITRILE, I.E., -83*C. THE CARBON FIBER SO PRODUCED CAN BE USED AS A REINFORCEMENT IN A COMPOSITE MATERIAL.
Inventors
- 👤 Yoneho Tabata
- 👤 Chihiro Oizumi
- 👤 Sugio Otani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:17
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |