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US4842837A
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Process for producing fine spherical silica
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1987-09-18
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Granted: 1989-06-27
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Expires: 2007-09-18
Abstract
Abstract A process for producing fine spherical silica, comprising a step of hydrolyzing an alkoxysilane in a mixed solution comprising water and alcohol and containing an alkaline catalyst, wherein the amount of said alkaline catalyst is 0.5 to 10 in molar ratio to the alkoxysilane used, the concentration of water in said mixed solution of water and alcohol in 5 to 20 mol/lit., and the reaction temperature for said hydrolysis is 30 DEG C. or more. According to this process, there can be obtained highly monodisperse spherical silica containing only a very small amount of impurities and having a particle size of 100 nm or less.
Inventors
- 👤 Takaaki Shimizu
- 👤 Toshihiro Okon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:15
CPC Classifications
B; B82; B82Y; B82Y30/00; C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/141; C01B33/145; C01B33/18; C01B33/181; C01P; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/30; C01P2004/32; C01P2004/60; C01P2004/64; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
85 words
A process for producing highly monodisperse fine spherical silica having a particle size of 100 nm or less, comprising a step of hydrolyzing an alkoxysilane in a mixed solution comprising water and alcohol and containing an alkaline catalyst, wherein the amount of said alkaline catalyst is 0.5 to 10 in molar ratio to the alkoxysilane used, the concentration of water in said mixed solution of water and alcohol is 5 to 20 mol/lit., and the reaction temperature in said hydrolysis is 30° C. or more.
Claim 2
Dependent Claim
85 words
A process for producing highly monodisperse fine spherical silica having a particle size of 100 nm or less, comprising a step of hydrolyzing an alkoxysilane in a mixed solution comprising water and alcohol and containing an alkaline catalyst, wherein the amount of said alkaline catalyst is 0.5 to 10 in molar ratio to the alkoxysilane used, the concentration of water in said mixed solution of water and alcohol is 5 to 20 mol/lit., and the reaction temperature in said hydrolysis is 30° C. or more.
Claim 3
Dependent Claim
37 words
The process of claim 1, wherein said alkoxysilane is represented by the general formula: (RO.sub.x)SiH.sub.4-x wherein R may be the same or different and represents an alkyl group, and x represents an integer of 1 to 4.
Claim 4
Dependent Claim
30 words
The process of claim 2, wherein said alkoxysilane is tetraalkoxysilane represented by the general formula: (RO).sub.4 Si wherein R may be the same or different and represents an alkyl group.
Claim 5
Dependent Claim
34 words
The process of claim 3, wherein said alkoxysilane is tetraalkoxysilane represented by the general formula: (RO).sub.4 Si wherein R may be the same or different and represents a methyl group or an ethyl group.
Claim 6
Dependent Claim
22 words
The process of claim 1, wherein said alkoxysilane is dropwise added in said mixed solution in the form of an alcohol solution.
Claim 7
Dependent Claim
24 words
The process of claim 1, wherein said alkoxysilane is used in an amount of 0.1 to 5 mol/lit. based on the whole reaction mixture.
Claim 8
Dependent Claim
28 words
The process of claim 1, wherein the alcohol in said mixed solution is a lower alcohol selected from the group consisting of methanol, ethanol, n-propanol, i-propanol and n-butanol.
Claim 9
Dependent Claim
16 words
The process of claim 7, wherein the alcohol in said mixed solution is methanol or ethanol.
Claim 10
Dependent Claim
20 words
The process of claim 1, wherein the water in said mixed solution is in concentration of 8 to 15 mol/lit.
Claim 11
Dependent Claim
26 words
The process of claim 1, wherein the amount of water used is 1.2 times or more the stoichiometric amount necessary for the hydrolysis of the alkoxysilane.
Claim 12
Dependent Claim
13 words
The process of claim 1, wherein said alkaline catalyst is ammonia or alkylamine.
Claim 13
Dependent Claim
25 words
The process of claim 1, wherein said alkaline catalyst is used in an amount of 1 to 5 in molar ratio to the alkoxysilane used.
Claim 14
Dependent Claim
19 words
The process of claim 1, wherein the reaction temperature in said hydrolysis of alkoxysilane is 30° to 50° C.
Claim 15
Dependent Claim
11 words
The process of claim 1, wherein said alkaline catalyst is ammonia.
Claim 16
Dependent Claim
24 words
The process of claim 1, wherein said alkoxysilane is used in an amount of 0.2 to 1 mol/liter, based on the whole reaction mixture.
Claim 17
Dependent Claim
19 words
The process of claim 1, wherein the reaction temperature in said hydrolysis of alkoxysilane is 35° to 45° C.
References Cited (Backward Citations)
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| 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 |