US3702800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cationic water-soluble polyvinyl alcohol retention aid
Assignee: WR Grace and Co
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Filing: 1971-01-29
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Granted: 1972-11-14
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Expires: 1991-01-29
Abstract
Abstract THIS INVENTION RELATES TO A CATIONIC WATER-SOLUBLE POLYVINYL ALCOHOL PREPARED FROM A WATER-SOLUBLE VINYL ACETATE/ N-VINYL-N-METHYL ACETAMIDE COPOLYMER BY HYDROLYSIS. THE HYDROLYZED COPOLYMER SIGNIFICANTLY ENHANCES THE RETENTION OF PIGMENT PARTICLES BY THE CELLULOSE FIBERS IN A PAPER PULP SLURRY.
Inventors
- 👤 Andrew G Tsuk
- 👤 Charles C Kirk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:55
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/33; D21H17/34; D21H17/41; D21H17/44; D21H17/45; D21H17/455; C; C08; C08F; C08F8/00; C08F8/44; D21H17/36; C08F2810/00; C08F2810/50
Claims Analysis
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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) | 1975-11-14 | 1976-05-15 | 1976-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-14 | 1980-05-15 | 1980-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-14 | 1984-05-15 | 1984-11-14 | $7700.00 | Window Closed / Lapsed |