JPS61174123A - Production of glass - Google Patents

Abstract

PURPOSE:To produce glass stably by mixing an alkoxide of Si with alcohol and water and by dissolving ammonia into alcohol in case of producing glass by a sol-gel process. CONSTITUTION:The alkoxide of Si is mixed with alcohol into which 0.01-1wt% of ammonia is dissolved and water to prepare a gel. The gel is sintered in an atmosphere-contg. oxygen to prepare a deposed glass. In addition, the use of water into which >=1 kinds of Pb(NO3)2, La(NO3)3, a solidified alkoxide of Ti by polymerization, ZrO(NO3)2 and a solidified alkoxide of Al by polymerization are dissolved is more preferable.

Description

[Detailed Description of the Invention] [Field of Application for Mold Molding] The present invention relates to a method for producing glass, and more specifically, a method for producing glass using a sol-gel method as one of the 81 alkoxide gold raw materials. Regarding.

[Conventional technology]

Currently, methods for producing preforms of original fibers include the vAD method, in which glass particles such as 8104 are passed through a flame and deposited on a target, and the resulting glass porous body is sintered into a glass lump. The mainstream method is to obtain This is an excellent method for obtaining high-purity porous glass at a relatively low cost. However, since this method is a gas phase reaction, it has the disadvantage that the substances that can be used as additives are limited to those that can be gasified.

Therefore, in recent years, as a method to compensate for this drawback, a metal alkoxide tube mainly composed of 51T is hydrolyzed to obtain silica gel or silica gel containing mineral additive elements, and after drying, the silica gel is treated to make it transparent. Methods for obtaining glass are being actively researched.

To give an example, an sl alkoxide such as 81 ("Hs) 4 is thoroughly stirred and mixed with ethanol, then water is added and further stirred to hydrolyze it. At this time, a pH II adjuster such as ammonia is added to the water. Precipitation of particles begins with the start of the hydrolysis reaction, and the reaction solution is transferred to a container coated with silicone on the inside, covered with aluminum foil or the like to prolong the drying time, and heated for example at 60 mL. The sol solution is gelled and the gel is dried by keeping it in a constant temperature bath at about ℃.The gel shrinks as it dries, and the drying process usually ends after a few days. A method is already known in which gel is dammed out and made non-porous by, for example, heating in an oxygen-containing He 2 atmosphere to produce transparent glass.

This so-called sol-gel method has the advantage that various substances can be easily added. However, there are also drawbacks such as the gel being easily broken during the drying and sintering process. To completely improve this, a method (Japanese Patent Publication No. 59-9497) has been implemented that uses ammonia water for rounding and hydrolysis to obtain a gel that has a low bulk density and is difficult to break during drying and sintering. .

[Problem that the invention seeks to solve]

However, the method described in the above publication has the drawback that it is difficult to dope a substance that is insoluble in either alkaline water or alcohol. For example, Pbft
When doping is desired, it is easier to use, for example, Pb(No3)s because Pb alkoxide is extremely toxic. However, although PB(son) snow dissolves in water, it hardly dissolves in alkaline water or ethanol, making it difficult to dope with the above method. PI) (N
On ) In addition to z, other substances that exhibit such properties are:
For example, Z r O(N01 )2 * L'("s
)s *There are Mut alkoxides and Ti alkoxides that have become solid through polymerization.

In addition, if the amount of water used is small, slight differences in the amount of water will be magnified as a proportion, and the pH of the sol will change significantly, so it is easy to have large variations between manufacturing patches. There is also a drawback.

The present invention aims to eliminate these drawbacks of the conventional method, that is, to provide a means for obtaining a gel doped with a substance that does not easily crack during drying and sintering, and that is difficult to dissolve in aqueous ammonia or alcohol, and also provides a means for obtaining a gel doped with a substance that is difficult to dissolve during drying and sintering, and for each manufacturing patch. The object of the present invention is to provide a method for producing glass that is more stable and less prone to cracking during drying and sintering by reducing differences in the conditions.

[Means for solving problems]

The present invention provides a method for producing shigarasu by a sol-gel method by mixing sl alkoxide with alcohol and water, in which ammonia is dissolved in the alcohol.
This is a characteristic glass manufacturing method.

In a particularly preferred embodiment of the present invention, 1.0 pb (No. 3) is added to the water. La(NOs)s, alkoxide of Ti that has polymerized into a solid, zro(gos),
and the above-mentioned method for producing glass, in which at least one of the group consisting of alkoxides of AA that have been polymerized and solidified is dissolved.

The object of the present invention is achieved by dissolving ammonia in NH3t-alcohol. For example, gel gold is prepared by dissolving Mut alkoxide, zrO(Hog)s, etc., which has become solid through polymerization of PI)No3, in the water used for hydrolysis. By sintering this in an oxygen-containing atmosphere, a doped glass is obtained. Alternatively, a good solution may be added by dissolving, for example, a Ti alkoxide, Mu4Pb, etc., which has become solid by polymerizing with nitric acid, in water.

Furthermore, even when nothing is added as a dopant, the difference in gelling conditions for each production can be made smaller than when aqueous ammonia t is used.

The alcohol used in the present invention may be any alcohol such as methanol, ethanol, clopanol, butanol, etc., but ethanol is superior in terms of toxicity, solubility of ammonia, etc. In addition, in the method of the present invention, the amount of ammonia contained in the alcohol is about α01 to 1% by weight, particularly preferably about 105 to IIL3% by weight.Of course, other alcohols may be used depending on the purpose.

As an alkoxide of Sl, 81(oc H3)4
Either ゜81(OC2Hs)4 is good. Other alkoxides can also be used, but they are less effective.

[Effect]

By using the present invention, water can be kept neutral or acidic until mixing, and various substances that cannot be dissolved in alkalinity can be dissolved. Since it becomes alkaline at the same time as mixing, even if particles precipitate, by selecting an appropriate ammonia concentration in the alcohol, it is possible to gel the particles before they settle.

Furthermore, in general, alcohol is used in a larger amount than water in the sol-gel method, and the effect of an error in the same volume on the pTi of the sol solution is often smaller with alcohol. For example, a typical raw material composition is water 9F, 81(00H
1) 4 t 5 F, ! It is something like tanol 1t5f. Ammonia water dcw? Addition of too much or insufficient amount of ethanol (11,5/
9.0 )X(1/(L79)X(1=1゜6dcM3
Adding too much or under-spreading causes a change in pE to the same extent. Therefore, it can be said that when using ammonia-containing ethanol, there is less variation between manufacturing batches than when using ammonia water.

〔Example〕

Hereinafter, the method of the present invention will be specifically explained using examples.

Example 1 0a(OH)124t and MB40t54f1 were placed in water and heated with a burner to generate ammonia. This is passed through a pipe filled with silica gel and then introduced into ethanol to produce (15 wt % O) ammonia-containing jetanol.Hereinafter, when we refer to ammonia-containing ethanol, we refer to this ammonia-containing ethanol.

81 (00Ha) 49.5 f and the above Ammonian p
Ethanol IL5ff: Mix and add water 9. Of was added and further mixed. This was transferred to a test tube coated with silicone on the inside, wrapped lightly with aluminum foil for 7 tl, and placed in a constant temperature bath at 6 a.degree. The gel was dry after one week. When the bulk density of the obtained dry gel was measured, the average a 73
f/aMs, standard deviation aO2ficIll''. Five gels were sintered at 1300°C, and all were vitrified without cracking.

Comparative Example 1 A dry gel was obtained in the same manner as in Example 1, except that ethanol was used instead of ethanol containing ammonia. The bulk density was measured with an average of 1.24 f/cs" and a standard deviation of 317 cm".

The difference in bulk density between Example 1 and this example is highly significant. 5
Glass was obtained by sintering two gels at t-1300°C, but all five were broken.

Example 2 A dry gel was obtained in the same manner as in Example 1, except that Pb(NOs) rich α5t was dissolved in water.

This was sintered at 1300° C. to obtain a glass doped with 5 moles of 'E"bib"l.

Comparative Example 2 Pb (No, ), 1 in 11.5 t of ethanol
I added 5 tons and stirred vigorously, but it did not dissolve.

Water 9.0 f K Pb (-110n) x l 5
f t- Aqueous ammonia was added to the dissolved solution to make it neutral.

At this time, a large amount of white precipitate had formed.

Example 3 A dry gel was obtained in the same manner as in Example 1, except that MuA(ooIIs)s (LO8tt) was dissolved in water.

This tube was sintered at 1300° C. to obtain a glass doped with 1 mol of muL.

Comparative Example 3 AA(OOHa)s (L
O8t was added and stirred vigorously, but it did not dissolve.

Add water to 13g6 ammonia water and 6 drops9. MuL(OOIIs)s (L 08 t) was added to the Off mixture and stirred vigorously, but it did not dissolve.The average bulk density of the dry gel when hydrolyzed using aqueous ammonia at this concentration is: (L 8 f/ls'', the effect was less than that of Example 1 when 9 ethanol with ammonia was used.

〔Effect of the invention〕

The method for producing glass of the present invention has the advantage of being difficult to break during drying and sintering, and can produce a gel doped with a substance that is difficult to dissolve in ammonia water or alcohol, or There is little difference, and it is dry and dry.
It has the excellent effect that it is possible to obtain a gel that does not easily break during sintering, thereby allowing stable glass production.

Claims (2)

[Claims] (1) A method for producing glass by mixing Si alkoxide with alcohol and water and producing glass by a sol-gel method, which comprises dissolving ammonia in the alcohol. (2) In water, Pb(NO_3)_2, La(NO_
3)_3, Ti alkoxide that polymerized and became solid,
ZrO(NO_3)_2 and Al that polymerized and became solid
The method for producing glass according to claim 1, wherein at least one of the group consisting of alkoxides is dissolved.