Process for the production of condensation products which can be converted into glass
First Claim
1. A process for the production of substantially homogeneous condensation products, which are capable of being converted to glass by hydrolytic condensation of compounds of elements whose presence in the glass end product is desired, which comprises bringing a solution containing:
- (a) at least one compound of the formula (I);
space="preserve" listing-type="equation">SiR.sub.4 (I) in which radicals R are identical to or different from each other, and each R is a hydrolyzable group or hydroxyl group, or an oligomer derived therefrom or a combination thereof;
(b) at least one compound of the formula (II) or (III);
space="preserve" listing-type="equation">MR'"'"'.sub.3 (II)
space="preserve" listing-type="equation">TiR'"'"'.sub.4 (III) in which M represents Al or B; and
the radicals R'"'"', which are identical to or different from each other, are each a hydrolyzable group or hydroxyl group or a hydrolyzable aluminum salt or an oligomer derived from said compounds, or a combination thereof; and
(c) at least one hydrolyzable compound or at least one hydroxide, oxide or oxide hydrate of an element selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium;
into contact with at least an element of water stoichiometrically necessary for complete hydrolysis of said hydrolyzable groups present, in the presence of a complexing agent selected from the group consisting of β
-carbonyl carboxylic esters, and C2 -C5 carboxylic acids and their carboxylate ions, whereby the hydrolysis of said hydrolyzable compounds is effected substantially without loss of less reactive volatile starting compounds, and substantially without formation of precipitates from more reactive starting compounds during hydrolysis.
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Abstract
A process is described for the production of condensation products which be converted into glass, in which at least one silicon compound which can be hydrolyzed to form SiO2, at least one compound which can be hydrolyzed to form Al2 O3, B2 O3 or TiO2 and at least one hydrolyzable alkali metal compound or alkaline earth metal compound is brought into contact with at least the stoichiometrically necessary amount of water. The hydrolysis is carried out according to the invention in the presence of a complexing agent selected from the group consisting of β-carbonyl carboxylic esters and C2 to C5 carboxylic acids and their carboxylate ions, which prevents precipitates of hydrolysis products of the very reactive aluminum and boron compounds forming while the less reactive silicon compounds remain unchanged or are only partially hydrolyzed. After drying, the condensation products prepared in this way can be sintered with thermal compaction to form glass without it being necessary at the same time to significantly excede the glass-transition temperature of the particular glass.
13 Citations
18 Claims
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1. A process for the production of substantially homogeneous condensation products, which are capable of being converted to glass by hydrolytic condensation of compounds of elements whose presence in the glass end product is desired, which comprises bringing a solution containing:
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(a) at least one compound of the formula (I);
space="preserve" listing-type="equation">SiR.sub.4 (I)in which radicals R are identical to or different from each other, and each R is a hydrolyzable group or hydroxyl group, or an oligomer derived therefrom or a combination thereof; (b) at least one compound of the formula (II) or (III);
space="preserve" listing-type="equation">MR'"'"'.sub.3 (II)
space="preserve" listing-type="equation">TiR'"'"'.sub.4 (III)in which M represents Al or B; and
the radicals R'"'"', which are identical to or different from each other, are each a hydrolyzable group or hydroxyl group or a hydrolyzable aluminum salt or an oligomer derived from said compounds, or a combination thereof; and(c) at least one hydrolyzable compound or at least one hydroxide, oxide or oxide hydrate of an element selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium;
into contact with at least an element of water stoichiometrically necessary for complete hydrolysis of said hydrolyzable groups present, in the presence of a complexing agent selected from the group consisting of β
-carbonyl carboxylic esters, and C2 -C5 carboxylic acids and their carboxylate ions, whereby the hydrolysis of said hydrolyzable compounds is effected substantially without loss of less reactive volatile starting compounds, and substantially without formation of precipitates from more reactive starting compounds during hydrolysis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification
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- Resources
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Current AssigneeFraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
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Original AssigneeFraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
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InventorsStrehlow, Peter, Schmidt, Helmut
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Primary Examiner(s)KOSLOW, CAROL M
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Assistant Examiner(s)Bonner, Melissa
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Application NumberUS07/330,493Time in Patent Office474 DaysField of Search501/12, 252/315.3, 252/315.6, 252/315.7US Class Current501/12CPC Class CodesC03C 1/006 to produce glass through we...C08G 77/02 PolysilicatesC08G 77/56 Boron-containing linkages C...C08G 77/58 Metal-containing linkages C...
