JPS61286230A - Production of glass - Google Patents

Abstract

PURPOSE:To efficiently produce the glass which is hard to be broken while drying and has high uniformity by mixing the particles under a prescribed condition with a sol solution of the alkoxide of silicon to gelatinize said sol solution. CONSTITUTION:At least one kind of the material is, for instance, methoxide, ethoxide, etc., of silicon. The original granular particles of glass having >=0.005mu particle diameter which are so small as to produce the colloid are mixed with this gelatinizable sol solution to gelatinize the sol solution. The resultant gel is then dried and the dried gel is sintered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing glass, and more particularly, to a method for producing glass by a sol-gel method using cricon alkoxide as one of the raw materials. .

[Conventional technology]

Currently, methods for producing optical fiber preforms include the WAD method, 51at, etc. are introduced into a flame, glass fine particles are deposited on a target, and the resulting glass porous body is sintered. The mainstream method is to obtain lumps. 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, silica gel or silica gel containing additive elements is obtained by hydrolyzing a nine-metal alkoxyde mainly composed of Sl, and after drying the silica gel, a process such as making it non-porous is performed to make transparent glass. How to obtain it is being actively researched.

For example, after thoroughly stirring and mixing 81 alkoxides such as cricontetramethoxide 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. As the hydrolysis reaction begins, particles begin to precipitate. Transfer the reaction solution to a container coated with silicone on the inside, cover with aluminum foil, etc. to prolong drying time, and store in a constant temperature bath at, for example, 60°C. By keeping the sol inside, the sol solution gels and the gel dries. The gel shrinks as it dries, and drying is usually completed after several days. A method is already known in which the gel thus obtained is taken out and subjected to a pore-free treatment, such as heating in an oxygen-containing He atmosphere, to make it transparent vitrified.

In such a so-called sol-gel method, since alkoxides can be prepared for many metal elements, various substances can be easily added. Another advantage is that glass with extremely high uniformity can be obtained. However, on the other hand, it also has the disadvantage that the gel tends to crack when drying.

In order to prevent such cracking during drying and sintering, the present inventors have already proposed a method in Japanese Patent Application No. 15558/1983, in which particles of a size that cannot be turned into colloids are added to the sol solution. In Japanese Patent Application No. 60-96676, a powder containing a glass raw material is mixed with a sol liquid so that the sol liquid contains a thickener and glass raw material particles with a particle size of 1 micron or more. We have proposed a gelling method, and each method is highly effective.

[Problem that the invention seeks to solve]

However, the gel made by the above three methods cannot be dried,
Although effective in preventing cracking during sintering, the gels made by these methods have large gap diameters and are used in applications that require submicro/order uniformity, such as micro-optics such as planar waveguides and Rondo lenses. This may be undesirable when parts are manufactured using the sol-gel method.

It also becomes difficult to mask with photoresist.

The object of the present invention is to provide a method for obtaining a gel that is hard to crack when drying and has a high degree of uniformity, and for efficiently producing glass with high resistance to damage without foaming during sintering. It is.

[Means to Solve the Problems] The present invention adds particles having a particle size of α005μ or more and small enough to be in a colloidal state to a gelatable sol solution containing silicon alkoxide as at least one of the raw materials. The above object is achieved by a method for manufacturing glass, which is characterized in that after mixing, the sol solution is gelatinized, the resulting gel is dried, and the dried gel is sintered.

The present inventors have already proposed in Japanese Patent Application No. 59-192581 to add colloidal particles to the liquid at about 5 to 20 molar proportions at or before the time of hydrolysis of the alkoxide. . Further investigation into why the bulk density could be controlled by dispersing colloidal particles in this way revealed that colloidal particles do not act as nuclei for oxides that precipitate due to hydrolysis of alkoxides, resulting in a gel that is difficult to break. I knew I could get it.

In the present invention, the colloid particles may be added after hydrolysis has been completed as long as the sol solution is not gelled, and the amount of colloid particles is preferably approximately 100 moles or more of the alkoxide. This invention differs from the above invention in this point. Essentially, in the present invention, the colloidal particles exist in the gel regardless of hydrolysis, so that the gap size of the gel can be increased within a range that does not impair uniformity, and the colloidal particles can be prevented from cracking due to strain during drying. This results in a gel that is difficult to use.

If the diameter of the colloidal particles added at this time is small, the effect of preventing cracking will be small, so a particle diameter of α005μ or more is required. If the particle size is large, the effect of preventing υ cracks due to increasingly large gap diameter increases, but uniformity is impaired. In order to obtain a highly uniform gel that is hard to crack during drying, which is the objective of the present invention, the particles are preferably small enough to form a colloid, and their diameter is approximately Q, 5 μm or less.

It is also preferable that the particles have an appropriate thickening effect.

For the above reasons, the particles have a particle size α05μ or more and are small enough to form a cicoloid state, and a particularly preferable particle size is cL005μ or more and 11.5μ or less.

The amount of particles added varies greatly depending on the concentration of alkoxide, the particle size, composition, OB group density of the particles added, and other conditions, but in general, 100 moles or more of the glass component made from alkoxide is generally added. It is preferable. Mixing as much as possible to prevent the powder from clumping further often yields favorable results.

The components of the particles used in the method of the present invention may be any glass raw material. For example 810! , or Go to 5102, P
, AL, Ti, Zr, an.

A material containing an oxide such as Pb or Os can be used, but is not limited thereto.

In the present invention, at least one of the raw materials is silicon alkoxide, such as silicon methoxide, ethoxide, etc., and this is hydrolyzed to obtain silica gel or silica gel containing additive elements, but there are no particular limitations on the hydrolysis conditions. For example, add water after mixing with ethanol. Alternatively, a method such as adding water to which ammonia or the like as a PM adjuster is added is used. Further, the obtained gel may be dried and sintered using a conventional method.

In the present invention, the above-mentioned raw material containing at least silicon alkoxide may include other alkoxides in addition to silicone alkoxide, such as Ge, B, P, At,
Al; oxides such as Ti, Zr, and Eln may be added. Further, various dopant elements may be included in the sol solution in a form other than alkoxide, for example, in the form of an aqueous salt solution.

After the particles are mixed into the sol solution, the sol solution is dried by a conventional method to form a dry gel.

By imparting a dopant distribution to the thus obtained gel and sintering it, various microscopic optical components can be obtained. Examples of micro optical components include optical circuits such as planar waveguides,
Examples include Rondo lenses.

For example, the steps for manufacturing a planar waveguide according to the method of the present invention are as follows. The gel on a flat plate obtained by the above method of the present invention is impregnated with alcohol, and then immersed in an alcoholic solution of Go oxide for several tens of seconds. This forms a layer containing Ge alkoxide on the surface. By soaking this in water diluted with alcohol,
Ge alkoxide on the surface undergoes hydrolysis, and a layer containing Gm01 is formed on the surface of the gel.

By drying, sintering and etching this,
A planar waveguide can be obtained. By creating a pattern on a flat gel using photoresist and performing the above steps, a recessed waveguide can be obtained, eliminating the need for etching.

For example, the steps for manufacturing Rondo lenses according to the method of the present invention are as follows. A rond-like gel PC08NO3 aqueous solution obtained by the method of the present invention is impregnated. This is soaked in an aqueous solution of HsBO8 for several minutes to obtain a gel in which the 0sNO3 concentration gradually decreases and the H3BO3 concentration gradually increases toward the periphery. This is vacuum dried and sintered to dry at low temperatures and in a short time. As a result, a Rondo lens having a refractive index distribution in the radial direction is obtained.

The gel obtained by the present invention does not easily crack during drying or doping, has high uniformity, and can easily create a precise dopant distribution.

Therefore, it is particularly suitable for manufacturing the above-mentioned micro optical components.

The glass produced according to the present invention is not limited to a lump, but may be in the form of a film or a fiber. For example, if the sol obtained according to the present invention is applied onto a glass substrate and then dried, a gel film with a thickness of several microns or more can be obtained. If this is sintered, a glass film with a thickness of several microns or more can be obtained. With a sol solution that uses only alkoxide as a raw material and does not contain powder as in the present invention, it is difficult to form a film with a thickness of 1 μ or more using the same method because the film will crack.

〔Example〕

The method of the present invention will be specifically explained below using Examples and Comparative Examples.

Example 1 81(ocHs)4'A mol and ethanol A mol were mixed with a magnetic stirrer, and 1 mol of boric acid was added to the mixture.
1 mole of 1.91 aqueous anthonia containing 150 moles was added and further mixed. Put this in a mixer, and the particle size α0
Silica particles of approximately 5μ (commercial product, trade name Aerosil 0X)
-50) Add 402 and stir vigorously9. After transferring this to a beaker and degassing it at a pressure of about 60 Torr,
It was placed in a pipe with an inner diameter of 10 mm.

After gelling at room temperature, it was extruded in water and dried on aluminum foil at room temperature. When this was calcined in air at 500°C and sintered in He at 1450°C, a glass could be obtained without cracking.

Example 2 A dried gel was obtained in the same manner as in Example 1, except that 40 particles of powder that had been attached to the matsufuru during VAD soot application were used as colloidal particles, no boric acid was added to the raw materials, and the amount of ammonia water was changed to 13 yuan. After calcining this gel at 900℃,
The 0-layer material was impregnated with an aqueous fluoric acid solution and dried again. 900℃
This was done to prevent cracking when soaking in the pre-baked boric acid aqueous solution. The thus obtained gel was calcined in air at a temperature of 500° C. and then sintered in 1450 cHe to obtain a glass without cracking.

Example 3 As colloidal particles, 7-lion particles (with a particle size of approximately α012μ)
A gel in a 10 φ pipe was obtained in the same manner as in Example 1, except that 15f (commercially available under the trade name Aerosil) was added, the amount of boric acid was 17,100 mol, and the amount of ammonia water was 11.

This gel was extruded in water, half of it was placed in a 20 mm diameter pipe for slow drying, and the other half was placed on aluminum foil and both were dried at room temperature. The former dries without cracking and is 50
After calcination in air at 0°C, the glass was sintered in He 2 at 1450°C to obtain a glass. The latter cracked during drying, but the pieces were relatively large, about 4 to 5 pieces.

Comparative Example 1 The same procedure as Example 3 was carried out except that silica particles were not added. The material dried in a 20 φ pipe had cracks and foamed when sintering was attempted. Those dried on aluminum foil were shattered and the pieces were small, ranging from 1 to 21 pieces.

Example 4 A plate of fluorine-containing quartz glass (refractive index 1.453) was immersed in the sol solution obtained in the same manner as in Example 1, pulled up, placed in a Petri dish, covered with a lid, and gently dried. After calcining this in air at a temperature of 500°C, it was heated to 1450°C.
The resulting material was sintered in an oxyhydrogen flame to obtain a transparent glass film. This film thickness was approximately 50 f, which was sufficient for use in applications such as planar waveguides.

Comparative Example 2 A fluorine-containing quartz glass plate was immersed in the sol solution obtained in the same manner as in Comparative Example 1, pulled up, placed in a petri dish, and gently dried by 7 tumbles. The resulting gel film had a thickness of about 0.3μ. When the gel film was soaked in a sol solution and dried twice to increase the film thickness, the gel film was cracked.

Example 5 The gel obtained in Example 2 was polished into a plate shape and then calcined at 900°C. After soaking this with ethanol, G e (
It was immersed in a 3% ethanol solution of 0xHs) for 30 seconds, and then immediately immersed in ethanol for 1 second. Subsequently, the sample was soaked in a solution prepared by adding 1 drop of 13% ammonia water to 20 f of a 50% aqueous solution of ethanol and left for 60 minutes. After this was poured out and dried, it was impregnated with a 10% boric acid aqueous solution and dried again.

This was calcined in air at 500°C and sintered in He at 1450°C to obtain a planar waveguide base material having a skin with a high refractive index on the surface.

Example 6 The calcined gel obtained in the same manner as in Example 5 was masked with 7 Otoresist, and after cutting miso paste with a width of about 50 f, it was impregnated with ethanol. Thereafter, a channel type planar waveguide could be obtained in the same manner as in Example 5.

Comparative Example 7 120t of silica particles with a particle size of 1012μ and 300f of water
After mixing with a mixer and drying with a drier, silica particles were granulated.

B1 (OClls) a ' A mole and a mole of ethanol are mixed with a magnetic stirrer, and [lL5%
After adding 1 mol of ammonia water and further mixing, this was placed in a mixer. Granulated silica particles 2 in 9
52 was added and stirred vigorously.

This was transferred to a beaker and degassed at a pressure of about 40 Torr, gelled in a pipe with an inner diameter of 10 mm at room temperature, extruded in water, and then placed on aluminum foil. An attempt was made to polish this gel into a plate shape and mask it with photoresist, but the gap was so large that the photoresist soaked into the gel and could not be marked.

(Effects of the invention) The method of the present invention prevents cracking during drying and foaming during sintering.
Moreover, it has the excellent effect of being able to obtain a gel with high uniformity, and thereby efficiently producing glass with high uniformity.

Claims (1)

[Claims] (1) Particles having a particle size of 0.005μ or more and small enough to be in a colloidal state are mixed into a gelable sol liquid in which at least one of the raw materials is a silicon alkoxide, and then the sol liquid is gelled. hand,
A method for producing glass, which comprises drying the gel thus obtained and sintering the dried gel.