Patent US2587064A successfully refreshed from Google Patents.
US2587064A
Expired / Lapsed
US
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Method of bleaching wood pulp
Assignee: International Paper Canada Inc
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Filing: 1949-03-09
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Granted: 1952-02-26
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Expires: 1969-03-09
Abstract
No abstract record available.
Inventors
- 👤 Rapson William Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:14
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/12; D21C9/14; D21C9/144
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
109 words
A PROCESS FOR COMPLETING THE BLEACHING OF PARTIALLY BLEACHED CHEMICAL WOOD PULP COMPRISING THE STEPS OF ADDING CHLORINE DIOXIDE TO AN AQUEOUS SUSPENSION OF SAID PULP, PERMITTING SAID CHLORINE DIOXIDE TO ACT ON SAID PULP FOR A SUBSTANTIAL LENGTH OF TIME. MAINTAINING THE PH WITHIN THE RANGE OF 7 TO 10 DURING SUCH ACTION, AND AFTER SUBSTANTIALLY EXHAUSTING THE CHLORINE DIOXIDE AS AN ACTIVE BLEACHANT IN THE RESULTING SUSPENSION ADDING TO SAID PULP A QUANTITY OF AN ALKALINE HYPOCHLORITE AND AN ALKALINE HYDROXIDE WHEREBY TO PRODUCE WITHOUT SUBSTANTIAL DEGRADATION A BLEACHED PULP HAVING A BRIGHTNESS IN THE RANGE OF 90 TO 98.7 AND SUITABLE FOR CONVERSION INTO CELLULOSE DERIVATIVES.
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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) | 1955-02-25 | 1955-08-27 | 1956-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-02-25 | 1959-08-27 | 1960-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-02-25 | 1963-08-27 | 1964-02-26 | $7700.00 | Window Closed / Lapsed |