US3579464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nondecrepitating silica gel and method for its preparation
Assignee: WR Grace and Co
•
Filing: 1968-05-20
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Granted: 1971-05-18
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Expires: 1988-05-20
Abstract
Abstract CONVENTIONAL PARTIALLY DRIED SILICA HYDROGEL PARTICLES HAVING ABOUT 2-20% MOISTURE CONTENT ARE GROUND TO ABOUT 1-500 MICRONS. THIS POWDER IS THEN BLENDED WITH SILICA HYDROSOL SOLUTION IN PROPORTIONS SUCH THAT THE WEIGHT RATIO OF SILICA FROM THE HYDROGEL PARTICLES TO SILICA IN THE HYDROSOL IS ABOUT 15:11. THE RESULTANT MIXTURE IS THEN EXTRUDED, BEADED, PELLETED OR OTHERWISE SHAPED. THE THUS SHAPED PRODUCTS ARE THEN AGED, WASHED, DRIED AND ACTIVATED.
Inventors
- 👤 Harvey Rosen
- 👤 Ellsworth G Acker
- 👤 Hanju Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:26
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |