US4683128A
Expired / Lapsed
US
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Process for manufacturing high purity silica
Assignee: Mitsubishi Chemical Corp
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Filing: 1986-06-25
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Granted: 1987-07-28
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Expires: 2006-06-25
Abstract
Abstract This invention deals with a process for manufacturing high purity silica which comprises making an aqueous alkali silicate solution into fine fibrous gel in a coagulant, treating the fibrous gel obtained with an acid-containing solution, and then with water to extract and remove impurities; and optionallly heating a resulting silica at a temperature of 1,000 DEG C. or higher. Thus obtained silica is preferably used as a filler, especially, the one for resin compositions for encapsulating electronic parts; etc.
Inventors
- 👤 Koichi Orii
- 👤 Masashi Nishida
- 👤 Junsuke Yagi
- 👤 Iwao Ohshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:42
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C03; C03C; C03C13/00; C03C13/005; C01B33/12; C01B33/14; C01B33/152; C01B33/18; C01B33/181; C03B; C03B37/00; C03B37/01; C03B37/011; C03B37/08; C03B37/095; C01P; C01P2004/00; C01P2004/10; C01P2004/50; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
150 words
A process for manufacturing high purity silica having an alkali metal content of 0 to 10 ppm, a chlorine content of 0 to 3 ppm and a uranium content of 0 to 3 ppb, said process comprising: (1) a step of extruding an aqueous solution of an alkali silicate represented by the general formula: M.sub.2 O.nSiO.sub.2 wherein M is an alkali metal element and n is a number of moles of SiO 2 of 0.5 to 5, into a coagulating bath comprising a coagulant through a spinning nozzle having a bore diameter of 1 mm or less to coagulate the same, and thereby making the same into a fibrous gel, said aqueous solution having a viscosity in the range of 2 to 500 poise, and (2) a step of treating the fibrous gel obtained with an acid-containing solution, and then washing the same with water to extract and remove impurities.
Claim 2
Dependent Claim
150 words
A process for manufacturing high purity silica having an alkali metal content of 0 to 10 ppm, a chlorine content of 0 to 3 ppm and a uranium content of 0 to 3 ppb, said process comprising: (1) a step of extruding an aqueous solution of an alkali silicate represented by the general formula: M.sub.2 O.nSiO.sub.2 wherein M is an alkali metal element and n is a number of moles of SiO 2 of 0.5 to 5, into a coagulating bath comprising a coagulant through a spinning nozzle having a bore diameter of 1 mm or less to coagulate the same, and thereby making the same into a fibrous gel, said aqueous solution having a viscosity in the range of 2 to 500 poise, and (2) a step of treating the fibrous gel obtained with an acid-containing solution, and then washing the same with water to extract and remove impurities.
Claim 3
Dependent Claim
22 words
A process according to claim 1, wherein the temperature at the acid treatment of the fibrous gel is 50° C. or higher.
Claim 4
Dependent Claim
24 words
A process according to claim 1, which comprises further a step of heating the resulting silica at a temperature of 1,000° C. or higher.
Claim 5
Dependent Claim
18 words
A process according to claim 3, wherein the temperature of the heating ranges from 1,000° to 1,400° C.
Claim 6
Dependent Claim
20 words
A process according to claim 1, wherein the bore diameter of the spinning nozzle ranges from 0.05 to 1.0 mm.
Claim 7
Dependent Claim
20 words
A process according to claim 1, wherein the bore diameter of the spinning nozzle ranges from 0.1 to 0.3 mm.
Claim 8
Dependent Claim
35 words
A process according to claim 1, wherein the spinning nozzle is a nozzle made of a noble metal alloy or a TFE resin, or a nozzle coated on the nozzle surface with a TFE resin.
Claim 9
Dependent Claim
14 words
A process according to claim 7, wherein the noble metal alloy is gold-platinum alloy.
Claim 10
Dependent Claim
12 words
A process according to claim 1, wherein the fibrous gel contains bubbles.
Claim 11
Dependent Claim
42 words
A process according to claim 1, wherein the coagulant is a water soluble organic medium, and the acid treatment of the fibrous gel is carried out by using first a treating solution having an acid concentration of 30% by volume or less.
Claim 12
Dependent Claim
24 words
A process according to claim 10, which comprises further a step of heating the resulting silica at a temperature of 1,000° C. or higher.
Claim 13
Dependent Claim
28 words
A process according to claim 10, wherein the water-soluble organic medium is at least one member selected from the group consisting of alcohols, esters, ketones, amides, and dimethylsulfoxide.
Claim 14
Dependent Claim
21 words
A process according to claim 10, wherein the acid concentration of the treating solution ranges from 0.5 to 30% by volume.
Claim 15
Dependent Claim
21 words
A process according to claim 10, wherein the acid concentration of the treating solution ranges from 1 to 25% by volume.
Claim 16
Dependent Claim
21 words
A process according to claim 10, wherein the acid concentration of the treating solution ranges from 3 to 20% by volume.
Claim 17
Dependent Claim
22 words
A process according to claim 10, wherein the acid treatment of the fibrous gel is carried out in at least two stages.
Claim 18
Dependent Claim
24 words
A process according to claim 10, which uses an aqueous alkali silicate solution having a viscosity in the range of 10 to 200 poise.
Claim 19
Dependent Claim
45 words
A process according to claim 1, wherein the coagulant is an acid solution having an acid concentration of 4N or less, and the acid treatment of the fibrous gel is carried out by using a treating solution having an acid concentration of 4N or less.
Claim 20
Dependent Claim
24 words
A process according to claim 18, which comprises further a step of heating the resulting silica at a temperature of 1,000° C. or higher.
Claim 21
Dependent Claim
19 words
A process according to claim 18, wherein the acid concentration of the acid solution ranges from 0.1 to 4N.
Claim 22
Dependent Claim
19 words
A process according to claim 18, wherein the acid concentration of the acid solution ranges from 0.5 to 3N.
Claim 23
Dependent Claim
19 words
A process according to claim 18, wherein the acid concentration of the acid solution ranges from 1 to 2N.
Claim 24
Dependent Claim
19 words
A process according to claim 18, wherein the acid concentration of the treating solution ranges from 0.5 to 3N.
Claim 25
Dependent Claim
19 words
A process according to claim 18, wherein the acid concentration of the treating solution ranges from 1 to 2N.
Claim 26
Dependent Claim
22 words
A process according to claim 18, wherein the acid treatment of the fibrous gel is carried out in at least two stages.
Claim 27
Dependent Claim
24 words
A process according to claim 18, which uses an aqueous alkali silicate solution having a viscosity in the range of 2 to 200 poise.
Claim 28
Dependent Claim
24 words
A process according to claim 18, which uses an aqueous alkali silicate solution having a viscosity in the range of 10 to 100 poise.
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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) | 1990-07-27 | 1991-01-26 | 1991-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-27 | 1995-01-26 | 1995-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-27 | 1999-01-26 | 1999-07-28 | $7700.00 | Window Closed / Lapsed |