Patent US3720532A successfully refreshed from Google Patents.
US3720532A
Expired / Lapsed
US
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Hydrophobic silica
Assignee: WR Grace and Co Conn
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Filing: 1971-04-23
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Granted: 1973-03-13
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Expires: 1991-04-23
Abstract
Abstract HYDROPHOBIC SILICA MATERIALS ARE PRODUCED BY FLUID ENERGY MILLING A SILICA HYDROGEL AT A TEMPERATURE OF ABOUT 100* C. TO 215* C. AT AN ESSENTIALLY ATMOSPHERIC OR SUPERATMOSPHERIC PRESSURE TO YIELD A SILICA HYDROGEL HAVING AN ACTIVE SURFACE AND A SUBSTANTIAL SILANOL GROUP POPULATION, AND THEN CONTACTING THIS MILLED ACTIVE SILICA HYDROGEL PRODUCT WITH A STRAIGHT CHAIN ALCOHOL OF FROM 4 TO 20 CARBON ATOMS AT A TEMPERATURE OF ABOUT 135 TO 220*C.
Inventors
- 👤 E Simpson
- 👤 C Doyle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:01
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/0052; B01J13/0069; C; C09; C09C; C09C1/00; C09C1/28; C09C1/30; C09C1/3009; C09C1/3018; C09C1/3063; C01; C01P; C01P2006/00; C01P2006/60; C01P2006/90
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |