Patent US2640052A successfully refreshed from Google Patents.
US2640052A
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Alkali-lignin tanning agents and method of preparation
Assignee: Champion Paper and Fibre Co
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Filing: 1950-07-25
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Granted: 1953-05-26
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Expires: 1970-07-25
Abstract
No abstract record available.
Inventors
- 👤 Jr William B Stoddard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:45
CPC Classifications
C; C14; C14C; C14C3/00; C14C3/02; C14C3/08; C14C3/24
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
86 words
METHOD OF PREPARING A TANNING AGENT WHICH COMPRISES REACTING CHLORINE WITH ALKALI-LIGNIN IN THE PRESENCE OF AT LEAST SUFFICIENT WATER TO FORM A WET PASTE, CONTINUING THE REACTION UNTIL SAID ALKALI-LIGNIN DERIVATE FROM THE ACCOMPANYING 30 PER CENT OF COMBINED CHLORIDE, SEPARATING SAID ALKALI-LIGNIN DERIVATIVE FROM THE ACCOMPANYING LIQUOR, DISSOLVING SAID ALKALI-LIGNIN IN WATER BY ADDING ALKALI IN AN AMOUNT SUFFICIENT TO RAISE THE PH TO BETWEEN ABOUT 6 AND 10, AND ADJUSTING THE PH OF THE RESULTING SOLUTION TO AN ACID VALUE FOR TANNING HIDE.
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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) | 1956-05-25 | 1956-11-24 | 1957-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-25 | 1960-11-24 | 1961-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-25 | 1964-11-24 | 1965-05-26 | $7700.00 | Window Closed / Lapsed |