US3817826A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fractionated recovery of lignin and cellulose from bark
Assignee: A S TOTEN CELLULOSEFAB NO
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Filing: 1972-09-20
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Granted: 1974-06-18
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Expires: 1992-09-20
Abstract
Abstract LIGNIN AND CELLULOSE ARE RECOVERED FROM BARK. THE BARK IS SUBJECTED TO A TWO STAGE CHEMICAL TREATMENT, THE FIRST STAGE COMPRISING EXTRACTION OF THE LIGNIN COMPONENT WITH AN ALKALINE LIQUID AND RECOVERY OF THE LIGNIN FROM THE ALKALINE EXTRACT SOLUTION, AND THE SECOND STAGE COMPRISING DIGESTION OF THE EXTRACTION RESIDUE WHEREBY ESSENTIALLY PURE CELLULOSE IS OBTAINED.
Inventors
- 👤 J Hoye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:31
CPC Classifications
D; D21; D21C; D21C5/00
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 |