US2826478A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of bleaching mechanically-disintegrated wood pulp with hydrosulfite bleach containing an alkali metal citrate
Assignee: Rohm and Haas Co
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Filing: 1955-07-19
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Granted: 1958-03-11
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Expires: 1975-07-19
Abstract
No abstract record available.
Inventors
- 👤 Frederick L Scnucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:35
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1026; D21C9/1042
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
76 words
THE METHOD WHICH COMPRISES BLEACHING A MECHANCALLY-DISINTEGRATED WOOD PULP AT A CONSISTENCY OF ABOUT 0.5% TO 10% AND A TEMPERATURE OF 100*F. TO ABOUT 200*F. AND A PH OF ABOUT 4.5 TO 6.0 WITH 1/2 TO 3%, ON THE WEIGHT OF PULP, OF A WATER SOLUBLE HYDROSULFITE BLEACHING AGENT AND 1/4 TO 3%, ON THE WEIGHT OF PULP, OF AN ALKALI METAL CITRATE, AND 1/8 TO 1%, ON THE PULP WEIGHT, OF AN ALKALI METAL TETRABORATE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-03-10 | 1961-09-09 | 1962-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-03-10 | 1965-09-09 | 1966-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-03-10 | 1969-09-09 | 1970-03-11 | $7700.00 | Window Closed / Lapsed |