Patent US2789902A successfully refreshed from Google Patents.
US2789902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refining of wood pulp
Assignee: Celanese Corp
•
Filing: 1954-01-19
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Granted: 1957-04-23
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Expires: 1974-01-19
Abstract
No abstract record available.
Inventors
- 👤 George W Seymour
- 👤 Wayman Morris
- 👤 Helge P Holkestad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:47
CPC Classifications
C; C08; C08B; C08B1/00; C08B1/08; D; D21; D21C; D21C9/00; D21C9/08; D21C9/086
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
35 words
IN A PROCESS FOR THE PURIFICATION OF WOOD PULP, THE STEP WHICH COMPRISES SUBJECTING THE PULP TO A HOT CAUSTIC BOIL IN THE PRESENCE OF TALL OIL AND A POLYGLYCOL ETHER OF AN ALKYL PHENOL.
Claim 2
Dependent Claim
35 words
IN A PROCESS FOR THE PURIFICATION OF WOOD PULP, THE STEP WHICH COMPRISES SUBJECTING THE PULP TO A HOT CAUSTIC BOIL IN THE PRESENCE OF TALL OIL AND A POLYGLYCOL ETHER OF AN ALKYL PHENOL.
References Cited (Backward Citations)
US1833976A
Cited
US1847311A
Cited
US2128928A
Cited
US2213477A
Cited
DE740664C
Cited
US2596092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-04-22 | 1960-10-22 | 1961-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-04-22 | 1964-10-22 | 1965-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-04-22 | 1968-10-22 | 1969-04-23 | $7700.00 | Window Closed / Lapsed |