US3817825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bleaching and refining process for producing dissolving pulps
Assignee: TDK Micronas GmbH
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Filing: 1972-06-19
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Granted: 1974-06-18
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Expires: 1992-06-19
Abstract
Abstract DISSOLVING PULPS SUITABLE FOR USE IN THE MANUFACTURE OF VISCOSE RAYON ARE PREPARED FROM UNBLEACHED SULFITE PULPS BY A BLEACHING AND REFINING PROCESS INCLUDING THE STEPS OF (1) CHLORINATION; (2) COMBINED ALKALINE HYPOCHLORITE DILUTE CAUSTIC EXTRACTION; (3) COLD CAUSTIC EXTRACTION WITH CONCENTRATED CUASTIC SOLUTION AND (4) ALKALINE HYPHOCHLORITE TREATMENT.
Inventors
- 👤 L Maranville
- 👤 A Hughes
- 👤 R Conca
- 👤 H Hergert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:31
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/08; D21C9/083
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |