JPS6168329A - Glass manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] Kinoe 111j relates to a method for manufacturing glass,
Specifically, the present invention relates to a method for producing L-glass gold using a sol-gel method as a metal alkoxide gold raw material.

[Conventional technology]

Currently, the methods for producing Hikari 7 Eyeper preforms include ij, WAD method, t-a, etc., in which glass fine particles are passed through a 51c4 flame and deposited on all targets, and the resulting glass porous body is completely sintered. The mainstream method is to obtain crushed glass blocks. This is an excellent method for obtaining high-purity porous glass gold 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.

So, in recent years, this drawback? As a complementary method, sly
Silica gel made by hydrolyzing metal alkoxide as the main ingredient or silica gel containing additives? Is the silica gel completely dried and then treated to make it non-porous? Methods for obtaining transparent glass by this process are being actively researched.

For example, gold alkoxides such as silicon tetramethoxide, etc., are thoroughly pre-mixed with ethanol, and then water is added and further stirred for hydrolysis. At this time, it is preferable to add a pH adjuster such as ammonia to the water. Particles begin to precipitate with the start of the hydrolysis reaction, and the reaction bath liquid is transferred to a container coated with silicone on the inside, and placed in a constant temperature bath at about 60°C, for example, with aluminum foil or the like placed between them to increase the drying time. Gelification of the sol solution and drying of the gel are performed by slowly drying the sol solution. As it dries, it shrinks into a gel, and the drying process usually ends after a few days.

A method is already available in which the gel tMR obtained in this manner is taken out and subjected to a complete pore-free treatment such as heating in an oxygen-containing He TJ atmosphere to make it transparent vitrified.

This so-called sol-gel method has the advantage that alkoxides can be prepared for many metal elements, so that all kinds of substances can be easily added.

[Problem that the invention seeks to solve]

However, the above method also has the disadvantage that the gel tends to crack during the sintering process.

This cracking during sintering is thought to be due to the small pore diameter of the gel, which causes closed pores to form before water, alcohol, etc. escape during sintering. After closed pores are formed, when the closed pores are further heated, the pressure inside the closed pores increases and cracks occur. On the other hand, gels with large pore diameters that are difficult to form closed pores are easily sintered.

Therefore, in order to stably obtain a whole glass lump, it is necessary to stably obtain a gel with a large pore size.

The pore diameter can be controlled by controlling the bulk density of the gel, but conventionally it has been difficult to control the bulk density of the gel. The bulk density of a gel is determined by the degree of shrinkage during drying, and this shrinkage force is due to surface tension, and the degree of shrinkage is generally determined by the particle size and the surface tension of the dispersion medium.

Conventionally, it has been difficult to control the bulk density of gels because, firstly, it is not possible to control the particle size of the constituent particles, and secondly, is it possible to use an arbitrary dispersion medium? This is because you can't choose.

Regarding particle size, if all particles are generated by hydrolyzing a highly concentrated bath liquid, particles of various sizes will be produced, making it difficult to control according to the school policy. However, by creating a sol by hydrolyzing it in a dilute bath solution under appropriate conditions and drying it using a method that makes it easy to control the particle size of the resulting particles, such as spray drying the entire sol, it is possible to control the particle size distribution width of any particle size. Narrow particles are obtained. (Reference 5tt5
bar at al 001-1o1d Interf
ace 5science.

vol, 26 1968 p, 62; Ceramics vol. 1.16 No. 10 1981 p, 85
1) Conventionally, it was not possible to control the particle size of the particles that make up the entire gel, because if a dilute solution was completely hydrolyzed, it would not gel even if a sol was formed.
This is because they didn't get it.

As for the dispersion medium, conventionally it was not possible to select anything other than a mixture of water and alcohol. Moreover, if the hydrolysis conditions are all constant, even the ratio of water to alcohol is fixed. Furthermore, since the dispersion medium contains a large amount of alcohol, the freeze-drying method, which is a drying method that allows easy control of bulk density, requires extremely low temperatures and is not practical.

The present invention solves the drawbacks of the conventional sol-gel method detailed above, and creates a gel that is easy to control bulk density, has large pores, and is easy to sinter. It is an object of the present invention to provide a method for producing glass that is stably obtained.

[Means to solve all problems]

In view of the current situation, the present inventors conducted intensive research and found that by separating the process of making all the particles and the process of gelling and drying, the bulk density can be easily controlled and an easily sinterable gel can be obtained in a stable manner. I have come up with the idea that all of the above problems can be solved.

That is, the present invention provides a method for producing glass by fully hydrolyzing gold scrap alkoxide, in which the particles obtained by hydrolysis are once separated from the dispersion medium of the hydrolysis, and then mixed with an arbitrary dispersion medium. , followed by drying to obtain a dry gel, and providing a method for producing glass, characterized in that the glass is treated to make it non-porous.

In a particularly preferred embodiment of the present invention, the metal alkoxide is 81, B, Ge, P.

At, 8b, Ti, Zr, 8n, Y
, Pb $P process, Cs, and the like.

Moreover, as another particularly preferable embodiment of the present invention, B and Go are added to the arbitrary dispersion medium as additives.

P, At, 8b, Ti, Zr, El
At least one element or compound of elements selected from the group consisting of n, Y, Sr, Pb and aS
Adding more than one species to the glass thus produced? The above-mentioned glass manufacturing method t in which glass is contained can also be mentioned.

In the glass manufacturing method of the present invention, in the step of creating particles, the concentration required for gelation and other factors are not taken into consideration.
Particle gold is produced under conditions that allow easy control of particle size, such as by hydrolyzing a dilute bath solution and spray drying. The particles obtained by this process are added to any liquid (dispersion medium) having an appropriate surface tension, and then gradually dried. In this way, easily sinterable dry gel gold having a large pore diameter can be obtained with little variation. In addition, by using water for the liquid, freeze-drying can be carried out even at relatively high temperatures of -10° C. or higher, where the bulk density can be easily controlled. Furthermore, by adding an appropriate substance to the dispersion medium, it is possible to add the substance to the glass to change the properties of the glass. For example, by using water as a dispersion medium and adding boric acid to the water, it is possible to improve the refractive index of the produced glass.

The metal alkoxide used in the method of the present invention includes:
For example, “# B # oe e P t kt,
St), Ti.

Examples include methoxides, ethoxides, propoxides, butoxides of Zr, 8n, Y, Pb, L and Cs, etc. For example, when producing quartz glass, alkoxides of S1 or Hs1 and alkoxides of B and below are used. A mixture of one or more of the following is hydrolyzed.

Hydrolysis of the metal alkoxide in the present invention can be carried out by a conventional method, that is, by mixing alcohol and water to a concentration suitable for the hydrolysis reaction. The alcohol is appropriately selected from methanol, ethanol, globanol, butanol, and the like.

After the hydrolysis is completed, the obtained particles can be separated from the dispersion medium of the hydrolysis, that is, alcohol and water, by using conventional separation and drying means. For example, precipitated particles ti
After removing F', dry it or evaporate the dispersion medium to obtain a powder, and use commonly used powder drying methods such as spraying into a high temperature, blowing hot air, vacuum drying, and freeze drying. I can do it.

The particles obtained in this process are again mixed with an arbitrary dispersion medium, but in this case, the concentration can be adjusted to a concentration suitable for gelation.

Examples of the arbitrary dispersion medium include Fθ, Ou, and C.

Any liquid may be used as long as it contains only a small amount of impurities harmful to optical customization such as water, alcohols, acetone, etc., but is not limited to these.

In addition, in any of the above dispersion mediums, B,
Go, P, At, 8b, Ti, Zr
, 8n, Y, Sr, P'b and Cs
At least one element or compound selected from the group consisting of
By adding more than one species, the element can be included in the produced glass. These elements can be added, for example, as salts, alkoxides, etc., gold aqueous solutions, mineral R bath liquids, and the like. By adding this element, it is possible to change the refraction IKk and IL of the product glass.

The gel produced above is dried to obtain a dry gel.
Rapid drying can cause the gel to shrink and crack due to strain, so drying slowly or freeze-drying can avoid this type of cracking.

As mentioned above, if water/metal is used as an arbitrary dispersion medium, freeze-drying can be carried out even at a relatively high temperature of -io DEG C. or higher, which is advantageous in that the bulk density can be easily controlled.

Next, the dry gel is subjected to a non-porous 1H treatment, for example, a method of sintering it in a suitable atmosphere at a temperature lower than the melting point of the components. Sintering is carried out at a temperature of about 1200 to 1500°C.

〔Example〕

The entire method for manufacturing the glass of the present invention will be specifically explained below with reference to Examples.

Example 1 178 moles of tetramethyl silicate redistilled immediately before the experiment were added to 5 moles of ethanol and thoroughly mixed using a magnetic stirrer. Thereafter, a mixture of 2 moles of ethanol and 1 Qtult of saturated ammonia water was added and stirred vigorously. Thereafter, the mixture was kept at room temperature for 3 hours while being gently stirred, and then sprayed into a high temperature of 800° C. and dried. The particle size of the powder thus obtained was approximately α1 micron, with little variation.

This powder was added to 1 t2 ethanol 50- and dispersed using ultrasonic waves, and then heated and concentrated in a water bath. When the fluidity became high, the heating was stopped and the inner surface was coated with silicone gold, diameter 1.
21. The mixture was transferred to five test tubes each having a length of 105 cm, capped loosely with aluminum foil, and placed in a constant temperature bath at 60C. This was left to dry for 5 days to obtain a dried silica gel with a diameter of about B1)IK and a length of about 14 mm. The bulk density of this dry gel is the average [L
The standard deviation was 52 f/cm', a 01 S'/cWI', and this was sintered at 15QQC in a TE atmosphere to obtain transparent glass gold without cracks for all five dried gels.

Example 2 Powder made in Example 1 1f 7a1 Thiboric acid water bath solution 50m
After dispersing with ultrasonic waves, the mixture was heated and concentrated. When the fluidity became high, before stopping heating, the mixture was transferred to the same five test tubes as described above, capped loosely with aluminum foil, and placed in a constant temperature bath at 60°C.

It dried like this for 2 days, and the length became about 151w.
The mixture was taken out on a roller, slowly cooled in a refrigerator car (-20°C), frozen, and dried in vacuum while cooling with ice and a sodium chloride cryogen to obtain dried gel gold. The average bulk density of this dry gel is α4917 cm, and the standard deviation is Q, 0
197cm” Tehri, this is in the iHe atmosphere, 130
Sintering at 0° C. resulted in clear glass gold with no cracks for all five dried gels.

Comparative Example: 1/16 mole of silicon tetramethoxide, 1/4 mole of ethanol, 1 mole of gold was mixed in a Macnetex stirrer, and 3 drops of 13% ammonia water was added thereto, totaling 7x 1/2 mole of water.
After further mixing, the mixture was transferred to the same five test tubes as above, capped loosely with aluminum foil, and placed in a 60C constant temperature bath. After 7 days, #1 was completely dry and the diameter was 6111) l.
The length of grade 1 was about 11 gourds. The average bulk density of this dry gel was 1)L78f/3 standard deviation was 106t/3. Dry gel of kerosene 'e,,130 in He atmosphere
When sintered at 0°C, three of the five pieces were cracked and only very small pieces of transparent glass were obtained.

〔Effect of the invention〕

As is clear from the results of the above Examples and Comparative Examples, the method of the present invention can obtain a dry gel with a smaller bulk density and a narrower particle size distribution width than the conventional method, and the dry gel can be easily sintered. be.

In addition, once the particles generated by hydrolysis = 9 are separated, they are gelled in any dispersion medium, so if you use any dispersion medium, water, compared to the conventional method that contains a large amount of alcohol. Since it can be freeze-dried at a relatively high temperature, it is advantageous for rice production.

Therefore, according to the present invention, it is possible to easily control the particle size of the particles constituting the gel, which has been difficult to control in the past, and the bulk density of the dry gel can be easily controlled. As a result, a dry gel that can be sintered without cracking? It has excellent effects that can be easily obtained.

Claims (3)

[Claims] (1) In a method for producing glass by hydrolyzing metal alkoxides, the particles obtained by hydrolysis are once separated from the dispersion medium of the hydrolysis, mixed with any dispersion medium, and then dried. A method for producing glass, which comprises obtaining a dry gel and subjecting it to a treatment including non-porous treatment. (2) Metal alkoxide is Si, B, Ge, P, Al,
The method for producing glass according to claim (1), wherein the glass is an alkoxide of at least one element selected from the group consisting of Sb, Ti, Zr, Sn, Y, Pb, and Cs. (3) Additives such as B, Ge, P, and A to any dispersion medium.
l, Sb, Ti, Zr, Sn, Y, Sr, Pb and C
The method for producing glass according to claim (1), wherein at least one element or compound of an element selected from the group consisting of s is added, so that the element is contained in the glass produced thereby.