Patent EP0084438A2 successfully refreshed from Google Patents.
EP0084438A2
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EP
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Method of forming glass or ceramic article
Assignee: Corning Glass Works
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Filing: 1983-01-13
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Granted: —
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Expires: 2003-01-13
Abstract
Abstract Suspensions of fumed oxides, e.g. fumed silica, are prepared in non-aqueous media and the suspensions are used to cast shapes for glass or cermic products. The suspensions are destabilized prior to casting with an added gelling agent, cast before gelation, and then gelled, dried and, optionally, sintered to clear glass or void-free ceramic products.
Inventors
- 👤 George Walter Scherer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 22:53
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/12; C03C; C03C1/00; C03C1/006; C03C3/00; C03C3/04; C03C3/06; C03C2201/00; C03C2201/02; C03C2201/06; C03C2201/30; C03C2201/40; C03C2201/42; C03C2203/00; C03C2203/20; C03C2203/22
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
119 words
A method for making a porous or non-porous glass or ceramic product which comprises the steps of: (a) suspending a particulate fumed oxide in a non-aqueous liquid vehicle to provide a first stable fluid suspension of oxide particles, said particles having an average diameter not exceeding about 0.1 microns; (b) destabilizing the suspension by adding a gelling agent thereto, said agent being added in an amount at least effective to cause complete gelation of the suspension; (c) prior to gelation, forming the destabilized suspension into a selected configuration, said configuration thereafter being maintained at least until gelation has occurred; and (d) drying the gelled suspension by expelling the liquid vehicle therefrom to provide a microporous glass or ceramic product.
Claim 2
Independent Claim
119 words
A method for making a porous or non-porous glass or ceramic product which comprises the steps of: (a) suspending a particulate fumed oxide in a non-aqueous liquid vehicle to provide a first stable fluid suspension of oxide particles, said particles having an average diameter not exceeding about 0.1 microns; (b) destabilizing the suspension by adding a gelling agent thereto, said agent being added in an amount at least effective to cause complete gelation of the suspension; (c) prior to gelation, forming the destabilized suspension into a selected configuration, said configuration thereafter being maintained at least until gelation has occurred; and (d) drying the gelled suspension by expelling the liquid vehicle therefrom to provide a microporous glass or ceramic product.
Claim 3
Dependent Claim
34 words
A method in accordance with claim 1, which comprises the further step, after drying, of heating the microporous product to a temperature at least sufficient to at least partially sinter the fumed oxide particles.
Claim 4
Dependent Claim
33 words
A method in accordance with claim 2, wherein the microporous product is heated to a temperature at least sufficient to completely sinter the fumed oxide particles into a non-porous glass or ceramic product.
Claim 5
Dependent Claim
17 words
A method in accordance with claim 1,2 or 3, wherein the destabilized suspension is formed by casting.
Claim 6
Dependent Claim
23 words
A method in accordance with claim 4, wherein the casting is formed in a mould which is lined with a deformable polymeric sheet.
Claim 7
Independent Claim
29 words
A method in accordance with any preceding claim, wherein the vehicle is n-propanol, or another water- miscible organic liquid, or chloroform, n-hexane, methylene chloride, or another hydrophobic organic liquid.
Claim 8
Dependent Claim
15 words
A method in accordance with claim 6, wherein the suspension comprises an added dispersing agent.
Claim 9
Dependent Claim
18 words
A method in accordance with claim 7, wherein the added dispersing agent stabilizes the suspension by steric hindrance.
Claim 10
Independent Claim
23 words
A method in accordance with any preceding claim, wherein the fumed oxide has an average particle diameter in the range of 0.01-0.1 microns.
Claim 11
Dependent Claim
31 words
A method in accordance with claim 9, wherein the fumed oxide is doped or undoped fused silica or another amorphous fumed oxide, or Ti0 2 , or another crysalline fumed oxide.
Claim 12
Independent Claim
25 words
A method in accordance with any preceding claim, wherein the gelling agent comprises water, aqueous NH 4 0H or another acidic or basic aequous solution.
Claim 13
Dependent Claim
23 words
A method in accordance with claim 11, wherein the aqueous gelling agent is added to the suspension in combination with a vehicle-miscible liquid.
Claim 14
Independent Claim
21 words
A method in accordance with any one of claims 1 to 10, wherein the gelling agent is a non-aqueous vehicle-miscible liquid.
Claim 15
Dependent Claim
26 words
14 . A method in accordance with claim 13, wherein the gelling agent is an alkylamine selected from the group consisting of 1,3 diaminopropane and heptylamine.
Claim 16
Independent Claim
56 words
A method in accordance with any preceding claim, wherein prior to forming, the first mentioned fluid suspension is mixed with at least one additional suspension containing a particulate fumed oxide which differs in composition from the particulate fumed oxide present in the first mentioned suspension, to provide a mixed suspension containing a mixture of fumed oxides.
Claim 17
Dependent Claim
23 words
A method in accordance with claim 15, wherein mixing is accomplished before either the first suspension or the additional suspension has been destabilized.
Claim 18
Dependent Claim
27 words
A method in accordance with claim 15, wherein mixing is accomplished during or after at least one of said first suspension or additional suspension has been destabilized.
Claim 19
Independent Claim
47 words
A method in accordance with any one of claims 15 to 17, wherein the mixed first and additional suspensions are formed by casting as an overlayer upon at least one underlying layer, the underlying layer consisting essentially of a gelled non-aqueous suspension containing a mixture of oxides.
Claim 20
Dependent Claim
30 words
A method in accordance with claim 18, wherein the mixture of fumed oxides in the underlying layer differs in composition from the mixture of fumed oxides in the cast overlayer.
Claim 21
Dependent Claim
26 words
A method in accordance with claim 19, wherein the cast layers form an axial composition gradient in the selected configuration for the glass or ceramic product.
References Cited (Backward Citations)
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