US3853688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous filaments and yarns
Assignee: EIDP Inc
•
Filing: 1973-02-12
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Granted: 1974-12-10
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Expires: 1993-02-12
Abstract
Abstract Small diameter, but unusually strong polycrystalline alumina filaments are disclosed. They contain small randomly oriented grains, and contain a number of pores in which the volume of an average pore in the filaments is 600,000 cubic angstroms (A3) or less, and at least 60% of the pores have a volume less than 500,000 A3. The filaments have a diameter less than about 0.0008 inch. The filaments have a porosity of between 2 and 10% and are surprisingly strong, making them particularly adaptable for use as catalyst supports.
Inventors
- 👤 Ambrosio B D
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:27
CPC Classifications
B; B01; B01J; B01J35/00; B01J35/50; B01J35/58; B01J21/00; B01J21/02; B01J21/04; C; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62231; C04B35/62236; D; D01; D01F; D01F9/00; D02; D02G; D02G3/00; D02G3/02; D02G3/16; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2927
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
A CONTINUOUS POLYCRYSTALLINE ALLUMINA FILAMENT HAVING A DIAMETER LESS THAN ABOUT 0.0008 INCH WHICH CONTAINS RANDOMLY ORIENTED GRAINS HAVING A SIZE LESS THAN 2 MICRONS, AT LEAST ABOUT 90% OF SAID GRAINS HAVING A SIZE LESS THAN 0.5 MICRON; SAID FILAMENT HAVING A POROSITY OF BETWEEN ABOUT 2 AND ABOUT 10% AND CONTAINING PORES HAVING AN AVERAGE VOLUME EACH OF LESS THAN 600,000 CUBIC ANGSTROMS, WITH AT LEAST 60% OF THE PORES EACH HAVING A VOLUME OF LESS THAN 500,000 CUBIC ANSTROMS; SAID FILAMENT BEING AT LEAST 80% BY WEIGHT AL2O3 WITH THE PREDOMINANT CRYSTALLINE PHASE, AS DETECTED BY X-RAY DIFFRACTION, BEING ALPHA ALUMINA.
Claim 2
Dependent Claim
104 words
A CONTINUOUS POLYCRYSTALLINE ALLUMINA FILAMENT HAVING A DIAMETER LESS THAN ABOUT 0.0008 INCH WHICH CONTAINS RANDOMLY ORIENTED GRAINS HAVING A SIZE LESS THAN 2 MICRONS, AT LEAST ABOUT 90% OF SAID GRAINS HAVING A SIZE LESS THAN 0.5 MICRON; SAID FILAMENT HAVING A POROSITY OF BETWEEN ABOUT 2 AND ABOUT 10% AND CONTAINING PORES HAVING AN AVERAGE VOLUME EACH OF LESS THAN 600,000 CUBIC ANGSTROMS, WITH AT LEAST 60% OF THE PORES EACH HAVING A VOLUME OF LESS THAN 500,000 CUBIC ANSTROMS; SAID FILAMENT BEING AT LEAST 80% BY WEIGHT AL2O3 WITH THE PREDOMINANT CRYSTALLINE PHASE, AS DETECTED BY X-RAY DIFFRACTION, BEING ALPHA ALUMINA.
Claim 3
Dependent Claim
35 words
The filament of claim 1 wherein the average volume of each pore is less than 450,000 cubic angstroms, and at least 70% of the pores have a volume of less than 500,000 cubic angstroms each.
Claim 4
Dependent Claim
13 words
The filament of claim 2 wherein the filament diameter is about 0.0003 inch.
Claim 5
Dependent Claim
13 words
The filament of claim 1 wherein the filament is substantially 100% Alpha -alumina.
Claim 6
Dependent Claim
15 words
The filament of claim 4 which contains up to about 1% by weight magnesium oxide.
Claim 7
Dependent Claim
35 words
The filament of claim 1 which contains between about 1-20% by weight silica, in addition to the alumina, up to 3% of an alkali metal oxide, and up to 1% of an alkalineearth metal oxide.
Claim 8
Dependent Claim
11 words
A yarn comprising at least 70 filaments defined as in claim
Claim 9
Dependent Claim
12 words
A yarn comprising at least 70 filaments defined as in claim 4.
Claim 10
Dependent Claim
12 words
A yarn comprising at least 70 filaments defined as in claim 6.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |