EP0385753A2
Expired / Lapsed
EP
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Synthetic silica glass articles and a method for manufacturing them
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1990-02-28
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Granted: —
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Expires: 2010-02-28
Abstract
Abstract A synthetic silica glass article made by hydrolyzing an alkoxysilane and thermally sintering the resulting silica; this synthetic silica glass article has a viscosity of not less than 10¹⁰ poise at 1400 °C, and contains, as metallic impurities, less than 1 ppm of Al, less than 0.2 ppm of Fe, less than 0.2 ppm of Na, less than 0.2 ppm of K, less than 0.01 ppm of Li, less than 0.2 ppm of Ca, less than 0.02 ppm of Ti, less than 0.01 ppm of B, less than 0.01 ppm of P, and less than 0.01 ppm of As.
Inventors
- 👤 Takaaki Shimizu
- 👤 Masatoshi Takita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 16:27
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/06; C03B; C03B19/00; C03B19/06; C03B19/066; C03B19/10; C03B19/1005; C03B19/106; C03B19/1065; C03B19/12; C03B20/00; C03C1/00; C03C1/006; C03B2201/00; C03B2201/02; C03B2201/03; C03B2201/04; C03B2201/06; C03B2201/07; C03B2201/20; C03B2201/23; C03C2201/00; C03C2201/06; C03C2201/20; C03C2201/23; C03C2203/00; C03C2203/20; C03C2203/26; Y; Y10; Y10S; Y10S65/00; Y10S65/90; Y10T; Y10T428/00; Y10T428/13; Y10T428/131; Y10T428/1314
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A synthetic silica glass article having a viscosity of not less than 10¹⁰ poise at 1400 °C, the content of metallic impurities being within the following ranges: Al, not more than 1 ppm; Fe, not more than 0.2 ppm; Na, not more than 0.2 ppm; K, not more than 0.2 ppm; Li, not more than 0.01 ppm; Ca, not more than 0.2 ppm; Ti, not more than 0.02 ppm; B, not more than 0.01 ppm; P, not more than 0.01 ppm; and As, not more than 0.01 ppm.
Claim 2
Dependent Claim
88 words
A synthetic silica glass article having a viscosity of not less than 10¹⁰ poise at 1400 °C, the content of metallic impurities being within the following ranges: Al, not more than 1 ppm; Fe, not more than 0.2 ppm; Na, not more than 0.2 ppm; K, not more than 0.2 ppm; Li, not more than 0.01 ppm; Ca, not more than 0.2 ppm; Ti, not more than 0.02 ppm; B, not more than 0.01 ppm; P, not more than 0.01 ppm; and As, not more than 0.01 ppm.
Claim 3
Dependent Claim
29 words
A synthetic silica glass article as claimed in claim 1, characterized in that the OH group content is not greater than 300 ppm, preferably not greater than 200 ppm.
Claim 4
Dependent Claim
21 words
A synthetic silica glass article as claimed in claim 1 or 2, characterized by being in the form of a crucible.
Claim 5
Independent Claim
115 words
A method for manufacturing a synthetic silica glass article, comprising the steps of: (a) obtaining silica by hydrolyzing an alkoxysilane in the presence of a basic catalyst ; (b) separating the silica from the hydrolysis medium; (c) heating the silica, preferably to about 1200 °C, to thereby remove water, solvent, and carbon; (d) sintering the silica at a temperature from about 1500 °C to 2000 °C; (e) pulverizing and sieving the sintered silica to thereby obtain synthetic silica glass powder; (f) treating the silica glass powder with an acid, washing the same with water, and drying the same; and (g) sintering and shaping the silica glass powder at a temperature not less than 1700 °C.
Claim 6
Independent Claim
115 words
A method for manufacturing a synthetic silica glass article, comprising the steps of: (a) obtaining silica by hydrolyzing an alkoxysilane in the presence of a basic catalyst ; (b) separating the silica from the hydrolysis medium; (c) heating the silica, preferably to about 1200 °C, to thereby remove water, solvent, and carbon; (d) sintering the silica at a temperature from about 1500 °C to 2000 °C; (e) pulverizing and sieving the sintered silica to thereby obtain synthetic silica glass powder; (f) treating the silica glass powder with an acid, washing the same with water, and drying the same; and (g) sintering and shaping the silica glass powder at a temperature not less than 1700 °C.
Claim 7
Dependent Claim
15 words
A method as claimed in claim 4, characterized in that the said alkoxysilane is methoxysilane.
Claim 8
Dependent Claim
34 words
A method as claimed in claim 4 or 5, characterized in that the amount of the water adsorbed to the synthetic silica glass powder is not greater than 0.05 weight percent at step (g).
Claim 9
Independent Claim
22 words
A method as claimed in any of claims 4 to 6, characterized in that the synthetic silica glass article is a crucible.
Claim 10
Independent Claim
20 words
A method as claimed in any of claims 4 to 7, characterized in that the said basic catalyst is ammonia.
Claim 11
Dependent Claim
87 words
A synthetic silica glass having a viscosity of not less than 10¹⁰ poise at 1400 °C, the content of metallic impurities being within the following ranges: Al, not more than 1 ppm; Fe, not more than 0.2 ppm; Na, not more than 0.2 ppm; K, not more than 0.2 ppm; Li, not more than 0.01 ppm; Ca, not more than 0.2 ppm; Ti, not more than 0.02 ppm; B, not more than 0.01 ppm; P, not more than 0.01 ppm; and As, no more than 0.01 ppm.
Claim 12
Dependent Claim
87 words
A synthetic silica glass having a viscosity of not less than 10¹⁰ poise at 1400 °C, the content of metallic impurities being within the following ranges: Al, not more than 1 ppm; Fe, not more than 0.2 ppm; Na, not more than 0.2 ppm; K, not more than 0.2 ppm; Li, not more than 0.01 ppm; Ca, not more than 0.2 ppm; Ti, not more than 0.02 ppm; B, not more than 0.01 ppm; P, not more than 0.01 ppm; and As, no more than 0.01 ppm.
Claim 13
Dependent Claim
28 words
A synthetic silica glass as claimed in claim 9, characterized in that the OH group content is not greater than 300 ppm, preferably not greater than 200 ppm.
References Cited (Backward Citations)
No citation records indexed.
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