JPS61256928A - Production of glass - Google Patents

Abstract

PURPOSE:To stably glass produce without generating cracks by mixing a thickener and glass raw material particles of a specific grain size with a sol liquid contg. alkoxide of silicon as a raw material, gelling the mixture, drying the gel and sintering the same. CONSTITUTION:Alkoxide of Si such as Si(OCH3)4 is used for at least one of the raw materials and others such as ethanol and ammonia are added thereto to obtain the 1st sol liquid which can be gelled. The powder contg. the thickener and glass raw material particles of 1mu grain size or above are mixed with the 1st sol liquid, by which the 2nd sol liquid is obtd. The above-mentioned thickener is preferably the pulverous particles of the glass raw material and the adequate grain size thereof is about 0.005-1mu. The secondary particles of average 1-100mu grain size formed by flocculating the pulverous particles of the glass raw material are used as the above-mentioned powder and are preferably crushed partly in the stage of mixing so as to act as the thickener for the pulverous particles. The above-mentioned 2nd sol liquid is gelled and is sintered after drying, by which the glass is obtd. without generating cracks.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing glass by the Sorge μ method.

[Conventional technology]

Currently, there are 81Cj methods for producing optical fiber preforms, including the vAp method.

etc. through a flame to deposit glass particles on a target, and sinter the resulting glass porous body to obtain a glass lump.
This method has become mainstream. 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 mainly composed of Sl is hydrolyzed to obtain silica gel or silica gel containing additive elements, and after drying the silicage μ, a process such as making it non-porous is performed to make transparent glass. Methods to obtain this are being actively researched.

For example, after thoroughly stirring and mixing an os1 alkoxide such as silicon tetramethoxide with ethanol,
Add water and stir further for hydrolysis. At this time, it is preferable to add a pH adjuster such as ammonia to the water. Particle precipitation begins with the start of the hydrolysis reaction, and the reaction solution is poured into a pipe with one end sealed to form a gel.

After gelling, extrude it in water and transfer it to a pipe with a slightly larger inner diameter to dry it.

The gel shrinks as it dries. The thus obtained gel is taken out and subjected to a porosity treatment such as heating in a He atmosphere containing oxygen and chlorine to obtain transparent glass.

This so-called sol-gel method has the advantage that various substances can be easily added.

[Problem that the invention seeks to solve]

However, the conventional method described above has drawbacks such as the gel being easily broken during the drying and sintering process.

In order to eliminate these drawbacks, the present inventors have already proposed adding particles of a size that may or may not form a colloid to the sol, and have achieved results. (Special request 1976
9-192581.60-13538) The terms sol and gel were originally defined for colloids, but here they are used to refer to sol and gel, which contain particles that are too large to become colloids. We will also call μ sol and geμ.

However, when using this method to add particles that are too large to form a colloid, some particles tend to sink to the bottom before gelation is complete, and the bulk density of the gel may differ between the top and bottom of the gel. Alternatively, if the particles are completely submerged and then gelled, it becomes difficult to take out the gel, especially long gels, and even after taking out the gel, it has little elasticity and can be difficult to handle, such as breaking with a small strain. .

The present invention aims to eliminate the drawbacks of such conventional methods, that is, to provide a means for obtaining a gel that is hard to break during drying and sintering, is uniform, and is easy to handle, thereby providing a stable glass manufacturing method. purpose.

[Means for solving problems]

In the present invention, at least one of the raw materials is a silicon alkoxide.G) A powder containing a glass raw material is mixed with a first sol liquid that can be converted into a glass, and the second sol liquid obtained is gelled. In the method of obtaining glass by drying the powder and sintering the dried gel, the second sol obtained by mixing the first sol and the powder is mixed with a thickener and a particle size. The above object is achieved by a method for producing glass, which is characterized in that it contains glass raw material particles of 1 micron or more.

A particularly preferred embodiment of the present invention includes the above-mentioned method for producing glass, in which the thickener is fine particles of a glass raw material.

The method of the present invention will be explained in detail below.

As the alkoxide of cricon in the present invention, for example, 8i(OCH3), Si(OC2H5)4, etc. can be used, and the first sol liquid using these as one of the raw materials can be prepared by mixing silicon alkoxide with ethanol, etc. It is manufactured by a method such as mixing, adding ammonia water, and further mixing well.

Powder containing glass raw material is added to the obtained first sol liquid to obtain a second sol liquid, and the second sol liquid contains a thickener and glass raw material particles with a particle size of 1 micron or more. Choose a powder that contains glass raw materials so that

The particle size of the frit particles contained in the second sol is 1
This is because if it is less than -, the obtained gel will be a little more likely to crack during drying.

Further, the thickener of the present invention may be included in the powder, or may be added separately.

The thickener has the effect of preventing glass raw material particles having a particle size of 1 μm or more from sinking before gelation. What level of viscosity is appropriate?
Depends on gelation time, particle size, particle shape, etc. If the viscosity is too high, it will be difficult to degas or pour the sol into a mold, and if the viscosity is too low, the particles will sink to the bottom before gelation. Concentrations in between are preferred.

As the thickener in the present invention, fine particles of glass raw materials, water-soluble upper μ-loose, etc. can be used, but the thickener is not limited thereto, and any thickener that has the above-mentioned effect may be used. It is convenient to use fine particles of a glass raw material as a thickener because it does not need to be removed during sintering, unlike water-soluble micro-loose. Especially 810. The fine particles have a strong viscosity-forming effect, and are also inexpensive and easy to obtain with high purity. The diameter of these fine particles varies depending on the components, particle shape, OH group density, etc., but in general, it is approximately [LOO 5μ to 1μ, preferably α00′ 5μ to 0.5μ. If the shape of the particles is irregular, even if the particles are larger than this, they may exhibit a thickening effect. The amount added also varies depending on the conditions. It is best to add it to achieve the appropriate viscosity mentioned above.

Excellent results can be obtained when fine particles are lightly granulated to form secondary particles as the powder added to the first sol solution. In this case, when the powder is mixed with the first sol solution,
It is thought that a part of the secondary particles are broken and the broken particles act as a viscosity agent. The primary particles may be of any type as long as they provide an appropriate thickening effect. Although this value varies depending on the conditions, it seems that approximately α005 to 1μ is appropriate in most cases. If the primary particles are too small, the bonds between the particles tend to become strong, and the secondary particles may not be broken during mixing. Moreover, if the primary particles are too large, the thickening effect will be reduced, so it is sufficient to select an appropriate particle size according to the conditions without being limited to the above-mentioned range.

The diameter of the secondary particles is arbitrary, but the average secondary particle diameter is 1μ to 1μ.
When it is between 00μ, it seems that the resistance to cracking of the gel μ and the uniformity are particularly excellent.

If the secondary particle size is too small, the gel tends to crack easily during drying and sintering, and if it is too large, the gel tends to become non-uniform.

The methods for granulating primary particles include: dispersing the primary particles in a liquid, then spraying the liquid and freeze-drying the droplets; ■ placing the particles in a beaker or the like and heating them to evaporate the liquid; The following methods are known, but are limited to: ■ Putting it in a beaker or the like and drawing a vacuum and heating it to evaporate the liquid and crushing the residue; ■ Spraying it in a high temperature environment (spray drying). It's not a thing.

As a result of research, the present inventor found that granulation by spray drying is particularly excellent. This seems to be due to appropriate granulation strength, particle size, etc.

The gel obtained by the present invention is resistant to cracking when doped with a dopant and is resistant to uneven doping. Therefore, it is also suitable for manufacturing planar waveguides and rod lenses by non-uniformly doping dopants into the gel.

When doping uniformly, it is easier to use doped powder than to dope after gelation.
If calcining is necessary, it is often easier and more convenient to calcinate in powder form.

In order to dope the dopant, there are several methods, such as ■ doping it in the powder, ■ doping it in the first sol solution, and ■ infiltrating the solution containing the dopant into the gel μ. This method may also be used.

Examples of dopants used in the present invention include Go, P
, B, Cs, K, Na, Pb, Nd, Y
b, 8b, 8n, kL, etc., but are not limited to these. The dopants are doped in the form of oxides or oxidizable compounds so that they become oxides in the final glass.

To give an example of a specific doping method, OE doped powder can be obtained by dispersing 5102 colloid and Ge01 colloid in water and spray drying them. Also S10. A Cm-doped powder can be obtained by dispersing the colloid in a CsNO3 aqueous solution, spray-drying it, and calcining it in oxygen at about 600°C. In addition, K may be doped by dissolving KBr in the first sol solution,
Nd and B can be doped by impregnating the dry gel with an aqueous solution of NdI and H3BO3.

Also, although this is not a dopant, NH, .H
It is also possible to obtain glass containing fluorine by impregnating it with an aqueous solution of F' and then sintering it under appropriate conditions.

In addition, the gel obtained by the present invention has high uniformity (it can be made with little shrinkage during drying, and it is possible to form a relatively thick gel film of several tens of tones or more on glass rods, glass plates, etc.). be able to.

By sintering this under appropriate conditions, it is possible to form a different glass layer on a glass plate or glass plate.

〔Example〕

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

Example 1 Si(OCHs) 4504 g, ethanol/I/200
g, water 54? 69 was mixed to obtain a 3% silica sol solution. By spray drying this at 250° C., spherical silica particles with an average particle diameter of about 10 μm were obtained. The particles were strongly granulated and did not break easily.

Next 81 (OCH3) 41? p, ethanol IV2sg
, water containing one drop of 15% ammonia water19. The li+ was mixed well and placed in a mixer. In this, the silica powder s
A9 was added and mixed well. Furthermore, in this, particle size α05μ
When 45 g of silica powder (commercially available under the trade name Aeroge/L10X-50) was added and mixed, the viscosity increased significantly. Transfer this to a beaker and add 60 To
After deaerating the mixture at a pressure of approximately 1.5 mm, it was poured into a pipe with an inner diameter of 6 mm and one end sealed with Teflon tape to form a gel.

Afterwards, the tape was removed and the gel was pushed out into water.

A portion of this gel was placed on aluminum foil and dried overnight. After drying, soak Gemu with a 5% boric acid aqueous solution,
I dried it again. This was calcined in air at a temperature of 500°C and heated to 1450°C in He to obtain glass.

Comparative Example 1 A gel was obtained in a pipe in the same manner as in Example 1 except that silica powder having a particle size Q of about 05 μm was not added. There was no powder at the top of Geμ, and most of the particles had sunk to the bottom. The length of the portion containing a large amount of particles was approximately 50α. This gel could not be pushed out because of the large friction with the inner surface of the pipe.

Comparative Example 2 A gel was obtained in the same manner as in Example 1, except that no silica particles with a particle size of about 10 tones and about α05 μm were added.

Shikajige μ broke into pieces while drying.

Example 2 Particle size Q: 0.012μ instead of silica powder of about 05μ
A glass was obtained in the same manner as in Example 1, except that 15 g of silica powder (commercially available under the trade name Aeroge μ) was added.

Example 3 120g of silica particles with a particle size of about 0.012μ and 300g of water
g in a mixer and dried in a 120° C. constant temperature bath to granulate silica particles.

Next, Si(OCH3), 19 fl, ethanol/I
/23g, 19g of water containing 1 drop of 13thiammonia water was mixed and put into a mixer.When the granulated silica 259 was added to this mixture and mixed thoroughly, the viscosity increased significantly. This is because some of the crushed particles broke down and became fine particles.These were transferred to a beaker and heated to 60 Torr.
I degassed to a certain degree.

Thereafter, glass was obtained in the same manner as in Example 1.

Example 4 Silica particles with a particle size of about 15 μm were obtained by spray-drying about 5% of the sol solution at 250° C. on silica particles with a particle size of about α012 μm, and calcined at 900° C. These particles were weakly granulated and could be broken by simply placing them between a cover glass and a slide glass and lightly rubbing the glass.

Glass was obtained by using 15 g of this powder in place of the prepared silica of Example 3. The gel μ obtained at this time was superior to the gel of Example 5 in terms of strength and uniformity.

Example 5 The primary particle diameter is a, about Sμ, the secondary particles are irregular in shape, and the particle size (longest part) averages about 25μ, but ranges from less than 1μ to more than 100μ, and the secondary particles are fragile V Glass was obtained in the same manner as in Examples 3 and 4, except that 3ag of Rica powder was used.

Example 6 Glass was obtained in the same manner as in Example 5, except that a 20-T boric acid aqueous solution was impregnated into a 5-T boric acid aqueous solution and the sintering temperature was 1000°C.

The B2O2 concentration in this glass is about 12% by weight.

Example 7 Ge (OC2) was added to the dried gel obtained in the same manner as in Examples 5 and 6.
It was impregnated with a 1% ethanol solution of H5)4, and then placed in a 50% aqueous solution of ethanol for 5 minutes. After drying this gel, it was impregnated with a 5% boric acid aqueous solution and dried again.

Thereafter, it was sintered in the same manner as in Example 5 to obtain a Ge-doped glass.

Example 8 Dry gel μ was obtained in the same manner as in Examples 5 and 6.7 except that a 10 mmφ pipe was used instead of the 6 mmφ pipe. This geum was ground into a plate shape, impregnated with a 20% cesium nitrate aqueous solution, immersed in a 40% cesium nitrate aqueous solution for 5 seconds, and then dried again. After calcining this gel in air at 500°C,
The base material of the planar waveguide was sintered at 00°C and had a layer with a high refractive index on the surface.

Example 9 A plate-shaped dry gel was obtained in the same manner as in Example 8.

After impregnating Conokel with ethanol-μ, Ge(OC2
It was immersed in a 1% ethanol solution of Hs)i for 5 seconds, and then immersed in a 50% aqueous ethanol solution for 5 minutes. After drying this,
It was impregnated with a 5% aqueous solution and dried again.

After calcining the gel thus obtained at 500'C in air,
A base material for a planar waveguide having a layer with a high refractive index on the surface was obtained by sintering at 1450°C. Note that a dry gel obtained without adding powder will break if it is exposed to water, ethanol, etc., so it is not possible to create a waveguide using this method as it is.

Example 10 A sol solution obtained in the same manner as in Examples 5 to 9 was applied to the inner surface of a quartz pipe, dried, impregnated with a 5-chloride aqueous solution, calcined in air at 500°C, and then calcined in He at 1450°C. Sintered. When this pipe was heated from the outside with an oxyhydrogen flame, the film became transparent and a glass film of about 200 μm was attached to the inner surface of the pipe.

Comparative Example 5 A quartz pipe was coated with a sol solution in the same manner as in Example 10, except that no powder was added. However, it was not possible to obtain a dry gel film with a thickness of 1 μm or more without cracking.

(Effects of the Invention) The present invention has the excellent effect of being able to obtain a gel that is hard to break during drying and sintering, uniform and hard to break when handled, and thereby providing a stable glass manufacturing method. play.

Claims (5)

[Claims] (1) A gelatinable first sol liquid containing silicon alkoxide as at least one of the raw materials is mixed with a powder containing a glass raw material, and the obtained second sol liquid is gelled. In the method of obtaining glass by drying the dried gel and sintering the dried gel, the second sol solution obtained by mixing the first sol solution and the powder contains a thickener and a particle size of 1 micron or more. A method for producing glass, characterized in that it contains glass raw material particles. (2) The method for producing glass according to claim (1), wherein the thickener is fine particles of a glass raw material. (3) The powder is composed of fine particles of the glass raw material agglomerated to become secondary particles, and when mixed with the first sol liquid,
3. The method for producing glass according to claim 2, wherein a part of the secondary particles are broken and the broken particles serve as a thickener. (4) The method for manufacturing glass according to claim (3), wherein the powder is obtained by spray-drying a liquid containing fine particles of a glass raw material. (5) The powder has an average secondary particle size of 1 micron or more,
The method for producing glass according to claim 3 or claim 4, wherein the glass has a particle size of 100 microns or less.