Patent US1246335A successfully refreshed from Google Patents.
Patent US4180411A successfully refreshed from Google Patents.
US4180411A
Expired / Lapsed
US
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Microcrystalline cellulose as extrusion aid/combustible filler for alumina
Assignee: Wyeth Holdings LLC
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Filing: 1978-07-28
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Granted: 1979-12-25
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Expires: 1998-07-28
Abstract
Abstract The use of microcrystalline cellulose as an extrusion aid/combustible filler for rehydratable alumina allows the production of low density alumina substrates.
Inventors
- 👤 Robert H. Whitman
- 👤 William A. Barber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:27
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/06; C04B38/063; C04B38/0635; C04B38/0645; C04B38/0675; B; B01; B01J; B01J21/00; B01J21/02; B01J21/04; B01J37/00; B01J37/0009; B01J37/0018; C04B35/00; C04B35/01; C04B35/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
58 words
A method for preparing a low-density alumina substrate comprising mixing 60-90 percent by weight of a rehydratable alumina with 10-40 percent by weight of microcrystalline cellulose with sufficient water to yield a 45 to 70 percent solids mixture, extruding the mixture, curing the resultant extrudates, and calcining the extrudates at a temperature of from 1700° to 2000° F.
Claim 2
Independent Claim
58 words
A method for preparing a low-density alumina substrate comprising mixing 60-90 percent by weight of a rehydratable alumina with 10-40 percent by weight of microcrystalline cellulose with sufficient water to yield a 45 to 70 percent solids mixture, extruding the mixture, curing the resultant extrudates, and calcining the extrudates at a temperature of from 1700° to 2000° F.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the substrate is prepared with 65 to 80% rehydratable alumina.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the substrate is prepared with 10 to 30% microcrystalline cellulose.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein up to 15% by weight of the alumina is replaced by recycled alumina fines.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the mixture being extruded contains 50 to 57% solids.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein the extrudates are washed to remove soda.
Claim 8
Dependent Claim
22 words
The method of claim 1 wherein the substrate is prepared from 65-80% rehydratable alumina, 10-30% microcrystalline cellulose, and 0-15% recycled alumina fines.
References Cited (Backward Citations)
US3856708A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-24 | 1983-06-25 | 1983-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-24 | 1987-06-25 | 1987-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-24 | 1991-06-25 | 1991-12-25 | $7700.00 | Window Closed / Lapsed |