US5360834A
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Process for photoinitiated control of inorganic network formation in the sol-gel process
Assignee: Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV
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Filing: 1994-01-31
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Granted: 1994-11-01
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Expires: 2014-01-31
Abstract
Abstract A process is described for photoinitiated control of inorganic network fotion in the sol-gel process, which comprises either A) subjecting one or more hydrolytically polycondensable compounds of constituent elements of glass or ceramic, excluding silicon compounds containing polymerizable organic groups, to hydrolytic polycondensation in a liquid reaction medium to form a sol and irradiating the resulting sol in a structured or unstructured manner in the presence of a photoinitiator which can change the pH of the reaction medium on irradiation, using radiation of a wavelength range in which the photoinitiator absorbs; or B) liberating water in an anhydrous reaction medium which contains an alcohol, one or more hydrolytically polycondensable compounds of constituent elements of glass or ceramic and a photoinitiator which can liberate water by a photochemical reaction or a secondary reaction when irradiated, by structured or non-structured irradiation using radiation of a wavelength range in which the photoinitiator absorbs, and in this way effecting the hydrolytic polycondensation.
Inventors
- 👤 Michael Popall
- 👤 Jochen Schulz
- 👤 Helmut Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:15
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/0004; B01J13/0039; B01J19/00; B01J19/08; B01J19/12; B01J19/122; B01J19/123; C; C03; C03C; C03C1/00; C03C1/006; C03C1/008; C03C17/00; C03C17/02; C03C17/22; C03C17/23; C03C17/25
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A process for photoinitiated control of inorganic network formation in the sol-gel process; which consists essentially of: preparing an anhydrous reaction medium of an alcohol, a photoinitiator, a compound which can liberate water under acid or alkaline catalysis and one or more hydrolytically polycondensable compounds of constituent elements of glass or ceramic; and subjecting said medium to structured or non-structured irradiation employing radiation of a wavelength range in which the photoinitiator absorbs, thereby liberating water by a photochemical reaction in situ which effects hydrolytic polycondensation of said one or more polycondensable compounds.
Claim 2
Dependent Claim
92 words
A process for photoinitiated control of inorganic network formation in the sol-gel process; which consists essentially of: preparing an anhydrous reaction medium of an alcohol, a photoinitiator, a compound which can liberate water under acid or alkaline catalysis and one or more hydrolytically polycondensable compounds of constituent elements of glass or ceramic; and subjecting said medium to structured or non-structured irradiation employing radiation of a wavelength range in which the photoinitiator absorbs, thereby liberating water by a photochemical reaction in situ which effects hydrolytic polycondensation of said one or more polycondensable compounds.
Claim 3
Dependent Claim
28 words
The process as claimed in claim 1, wherein said polycondensable compounds are one or more compounds of elements selected from the group consisting of aluminum, titanium and zirconium.
Claim 4
Dependent Claim
13 words
The process of claim 1, wherein said irradiation step is conducted at intervals.
Claim 5
Dependent Claim
15 words
The process of claim 1, wherein said photoinitiator is a perbenzoic ester or dibenzoyl peroxide.
Claim 6
Dependent Claim
25 words
The process of claim 1, wherein said photoinitiator is a photodissociating compound selected from the group consisting of compounds containing a carbonyl or ketal group.
Claim 7
Dependent Claim
55 words
The process of claim 1, wherein the photoinitiator is selected from the group consisting of 1-hydroxycyclohexyl phenyl ketone, a mixture of 1-hydroxycyclohexyl phenyl ketone+benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, a mixture of aryl ketones of the benzophenone type, benzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, benzoin, 4,4'-dimethoxybenzoin, benzoin ethyl ether, benzoin isopropyl ether, benzil dimethyl ketal, 1,1,1-trichloroacetophenone, diethoxyacetophenone, and dibenzosuberone.
Claim 8
Dependent Claim
72 words
The process of claim 1, wherein said compound which eliminates water is a member selected from the group consisting of geminal diols, hemihydrates of aldehydes having more than 7 carbon atoms, compounds which contain a hydroxyl group in the α- or β-position relative to at least one group selected from the group consisting of carbonyl, carboxyl, nitrile, nitro and sulfonyl groups and tertiary alcohols which contain a hydrogen atom in the α-position.
Claim 9
Dependent Claim
31 words
The process of claim 1, wherein, in addition to the water liberated upon exposure of the reaction medium to irradiation, water is added to the reaction mixture after the irradiation step.
Claim 10
Dependent Claim
34 words
The process of claim 1, wherein said reaction medium is irradiated to the extent that polycondensation occurs to the sol state, and then the sol is subjected to further condensation to the gel state.
Claim 11
Dependent Claim
22 words
The process as claimed in claim 9, wherein the sol is further irradiated to convert the sol by polycondensation to a gel.
Claim 12
Dependent Claim
41 words
The process of claim 9, wherein after the polycondensation the resulting polycondensation product is subjected to a heat treatment in a temperature range of 550°-1200° C. for glass or 1300°-2000° C. for a ceramic or 90°-280° C. for inorganic-organic hybrid materials.
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