Patent US3707438A successfully refreshed from Google Patents.
US3707438A
Expired / Lapsed
US
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Method for the brightening of kraft pulp with tertiary butyl hydroperoxide
Assignee: Atlantic Richfield Co
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Filing: 1970-09-15
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Granted: 1972-12-26
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Expires: 1990-09-15
Abstract
Abstract METHOD FOR REPLACING ONE OR MORE OF THE CHLORINE OR CHLORINE-COMPOUND BLEACHING STEPS OF KRAFT PULP BY THE USE OF TERTIARY BUTYL HYDROPEROXIDE AS A BRIGHTENING AGENT IN AN ALKALINE MEDIUM, IN PARTICULAR AQUEOUS SODIUM HYDROXIDE OR SODIUM CARBONATE. THE AMOUNT OF TERTIARY BUTYL HYDROPEROXIDE AND ALKALINE MEDIUM REQUIRED DEPENDS UPON THE EXTENT OF THE PRIOR BLEACHING OF THE KRAFT PULP.
Inventors
- 👤 Robert M Lincoln
- 👤 Joseph A Meyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:48
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/16; D21C9/163
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-26 | 1976-06-26 | 1976-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-26 | 1980-06-26 | 1980-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-26 | 1984-06-26 | 1984-12-26 | $7700.00 | Window Closed / Lapsed |