US3565980A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Slip casting aqueous slurries of high melting point pitch and carbonizing to form carbon articles
Assignee: Kureha Corp
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Filing: 1969-01-27
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Granted: 1971-02-23
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Expires: 1989-01-27
Abstract
Abstract AQUEOUS BALL MILLED SLURRIES HAVING SOLIDS CONTENTS OF 5-50% BY WEIGHT CONTAINING WATER, PITCH HAVING A SOFTENING POINT ABOVE 170*C., AND 50 TO 80% BY WEIGHT ETHYL ALCOHOL, BASED ON THE WEIGHT OF PITCH, ARE SLIP CAST IN POROUS GYPSUM PLASTER MOLDS OF THE DESIRED SHAPE. THE CAST ARTICLES ARE THEN DRIED AND CARBONIZED. WHEN THE SOFTENING POINT OF THE PITCH IS BELOW 300*C. THE METHOD INCLUDES A FURTHER STEP OF HEATING THE DRIED ARTICLE IN AN OXIDIZING ATMOSPHERE TO 260-300*C. AT A HEATING RATE OF 0.2-3*C./MIN. PRIOR TO THE CARBONIZATION STEP. A FURTHER STEP OF GRAPHITISING IS ALSO DISCLOSED.
Inventors
- 👤 Sugio Otani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:20
CPC Classifications
C; C25; C25B; C25B11/00; C25B11/04; C25B11/042; C25B11/043; C04; C04B; C04B35/00; C04B35/515; C04B35/52; C04B35/528; C04B35/532
Claims Analysis
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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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |