US3382149A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bleaching of hardwood sulfite pulp with hydrogen peroxide, including pretreatment with alkali
Assignee: EIDP Inc
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Filing: 1964-10-29
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Granted: 1968-05-07
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Expires: 1984-10-29
Abstract
No abstract record available.
Inventors
- 👤 George L K Hoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:54
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1005
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
70 words
THE METHOD OF BLEACHING A HIGH-YIELD HARDWOOD SULFITE PULP COMPRISING TREATING SAID PULP AT A PULP CONSISTENCY OF 5 TO 40% WITH 0.3 TO 3% OF AN ALKALI, CALCULATED AS CASUTIC SODA AND BASED UPON THE DRY WEIGHT OF THE PULP, AT A TEMPERATURE NOT EXCEEDING 70*C. FOR A TIME NOT EXCEEDING 3 HOURS, WASHING THE PULP, AND THEN BLEACHING THE PULP WITH AN AQUEOUS ALKALINE HYDROGEN PEROXIDE BLEACH SOLUTION.
Claim 2
Independent Claim
70 words
THE METHOD OF BLEACHING A HIGH-YIELD HARDWOOD SULFITE PULP COMPRISING TREATING SAID PULP AT A PULP CONSISTENCY OF 5 TO 40% WITH 0.3 TO 3% OF AN ALKALI, CALCULATED AS CASUTIC SODA AND BASED UPON THE DRY WEIGHT OF THE PULP, AT A TEMPERATURE NOT EXCEEDING 70*C. FOR A TIME NOT EXCEEDING 3 HOURS, WASHING THE PULP, AND THEN BLEACHING THE PULP WITH AN AQUEOUS ALKALINE HYDROGEN PEROXIDE BLEACH SOLUTION.
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) | 1971-05-07 | 1971-11-06 | 1972-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-05-07 | 1975-11-06 | 1976-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-05-07 | 1979-11-06 | 1980-05-07 | $7700.00 | Window Closed / Lapsed |