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US4842832A
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Ultra-fine spherical particles of metal oxide and a method for the preparation thereof
Assignee: Idemitsu Kosan Co Ltd
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Filing: 1988-03-21
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Granted: 1989-06-27
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Expires: 2008-03-21
Abstract
Abstract Ultra-fine spherical particles of a metal oxide having an average particle diameter of 40 nm or smaller can be prepared by a method in which a vaporizable metal compound is vaporized and decomposed under heating to give ultra-fine particles of a metal oxide followed by immediate cooling down to a temperature at which coalescence of the fine particles are prevented from coalescence. The fine particles have characteristics such as an excellent power of ultraviolet scattering.
Inventors
- 👤 Hakuai Inoue
- 👤 Hiroshi Komiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:04
CPC Classifications
C; C01; C01B; C01B13/00; C01B13/14; C01B13/18; B; B82; B82Y; B82Y30/00; C01B13/20; C01G; C01G23/00; C01G23/04; C01G23/047; C01G23/07; C01G25/00; C01G25/02; C01P; C01P2002/00; C01P2002/02; C01P2002/04; C01P2002/70; C01P2002/72; C01P2002/80; C01P2002/84; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/04; C01P2004/30; C01P2004/32; C01P2004/50; C01P2004/51; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/12; C01P2006/80; C01P2006/82
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
A method for the preparation of ultra-fine spherical particles of a metal oxide having an average particle diameter of 40 nm or smaller comprising vaporizing a vaporizable metal to form a concentration of 0.06 to 10% by volume and decomposing the vaporizable metal compound by heating to a temperature not exceeding 600° C. in the presence of water vapor in an amount in the range of from 30 to 120 moles per mole of vaporized metal compound to give ultra-fine particles of a metal oxide, the decomposition being immediately followed by cooling by direct quenching with a cooling medium to a temperature not exceeding 100° C. and at which coalescence of the ultra-fine particles of the metal oxide no longer takes place.
Claim 2
Independent Claim
122 words
A method for the preparation of ultra-fine spherical particles of a metal oxide having an average particle diameter of 40 nm or smaller comprising vaporizing a vaporizable metal to form a concentration of 0.06 to 10% by volume and decomposing the vaporizable metal compound by heating to a temperature not exceeding 600° C. in the presence of water vapor in an amount in the range of from 30 to 120 moles per mole of vaporized metal compound to give ultra-fine particles of a metal oxide, the decomposition being immediately followed by cooling by direct quenching with a cooling medium to a temperature not exceeding 100° C. and at which coalescence of the ultra-fine particles of the metal oxide no longer takes place.
Claim 3
Dependent Claim
36 words
The method for the preparation according to claim 1 wherein the vaporizable metal compound is selected from the group consisting of titanium alkoxides, titanium halides, zirconium halides, organic zirconium compounds and alkoxides of rare earth metals.
Claim 4
Dependent Claim
29 words
The method for the preparation according to claim 1 wherein the decomposition of the vaporizable metal compound is performed in the absence of an oxygen-containing gas in the atmosphere.
Claim 5
Dependent Claim
19 words
The method for the preparation according to claim 1 wherein the metal oxide is titanium oxide or zirconium oxide.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein the vaporizable metal compound is heated to a temperature of 250° to 450° C. to decompose said compound.
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein the concentration of the vaporizable metal compound is 0.1 to 10% by volume.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein the vaporizable metal compound is heated for decomposition for 0.1 to 10 seconds.
Claim 9
Dependent Claim
14 words
The method of claim 7 wherein the heating time is 0.1 to 5 seconds.
References Cited (Backward Citations)
FR1383774A
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JPS5499796A
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JPS58172233A
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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) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |