JPH05124828A - Production of glass - Google Patents

Abstract

PURPOSE:To produce large-sized high quality glass in a short time at a low cost, to produce glass of desired shape near net shape or to produce functional glass by adding many components. CONSTITUTION:Particles as starting material for glass are dispersed in an org. solvent or water contg. an added binder to prepare a uniform slurry and this slurry is subjected to solid-liq. separation by centrifugal casting. The resulting solid is molded, dried and vitrified by sintering to produce glass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing glass such as single-component quartz glass suitable for high-temperature materials and optical materials, and multi-component borosilicate glass suitable for heat-resistant materials. The present invention relates to a glass manufacturing method capable of manufacturing a plate shape, a column shape, and a near net shape for a complicated shape.

[0002]

2. Description of the Related Art Conventionally, glass has been manufactured mainly by melting powder raw materials. In quartz glass, in addition to melting powder such as quartz, liquid such as silicon tetrachloride is used. Hydrolysis and melting method by oxyhydrogen flame of raw material, VAD
It is also manufactured by the (Vapour Axial Deposittion) method.

In recent years, attempts have been made to manufacture glass by a sol-gel method using a metal alkoxide as a raw material.

In addition, hot pressing, slip casting, CIP-H are used as a method for producing glass using powder as a raw material.
IP (Japanese Patent Laid-Open No. 1-119539) and the like have been proposed.

[0005]

However, the melting method requires a high temperature of 1400 ° C. or higher, and particularly in the production of quartz glass, the VAD method is 1500 ° C. or higher, and the oxyhydrogen flame hydrolysis and melting method is 2000 ° C. Since the above high temperature is required, the energy cost is high.

Although the sol-gel method can produce glass at a relatively low temperature of 1300 ° C. or lower, it is not easy to obtain a large glass because the gel as a glass precursor is easily broken during drying.

In the sol-gel method, in addition to this, gel drying can be performed by supercritical drying to obtain a gel without cracks in a short time, but a large high-pressure facility is required to obtain a large dried gel. However, there is a drawback that the equipment cost becomes extremely high.

Glass can be easily produced by using a hot press, but since the contamination from the press die is severe and a large number of bubbles are included in the obtained glass, only a low quality glass is produced. I can't get it.

In addition, as an attempt to manufacture glass from powders, glass is manufactured by slip casting, but in the case of normal pressure casting, thick glass cannot be obtained, and pressure casting In this case, there is a drawback that the manufacturing apparatus becomes complicated.

Further, the method for producing glass by CIP-HIP is extremely disadvantageous for producing glass because it requires extremely high pressure, and the equipment cost for producing large glass is enormous.

An object of the present invention is to solve the above-mentioned problems, to produce a large glass of high quality in a short time and at low cost, and a method of producing a glass having a desired shape with a near net shape. Another object of the present invention is to provide a method for producing a functional glass by adding multiple components.

[0012]

Means for Solving the Problems That is, the present invention is to disperse particles, which are raw materials for glass, in water or an organic solvent to which a binder is added to obtain a uniform slurry, and the slurry is subjected to solid-liquid separation by centrifugal casting. After the molding, the molded body is dried, sintered, and vitrified, which is a method for producing glass.

In the present invention, the particles used for the glass raw material are not particularly limited as long as they are compounds that form glass, regardless of whether they are metals or non-metals, and they are not limited to a single component and may be a multi-component or a multi-component. The main raw materials for glass are silicic acid, boric acid, phosphoric acid, or their soda salts and potassium salts. Further, the shape of the particles to be used can be variously spherical, subspherical, uneven, etc., but preferably spherical, more preferably monodisperse with uniform particle size rather than polydisperse. Since, as a result, a dense molded body can be obtained, it is possible to manufacture high-quality glass without bubbles. The particle size of the particles used is 0.
The range of 01 to 10 μm is preferable.

The raw material particles are dispersed in a solution of a binder-added water or an organic solvent to form a uniform slurry, and an organic polymer such as polyvinyl alcohol or a metal alkoxide hydrolyzate is used as the binder.

If desired, metallic or non-metallic additives can be used. For example, a zirconium salt for the purpose of imparting alkali resistance, a titanium salt for the purpose of imparting a low thermal expansion property, a cerium salt for the purpose of controlling the ultraviolet transmittance and the like can be added. These are added to the slurry as a powder or mixed with the slurry as a solution for use.

According to the present invention, the slurry is subjected to solid-liquid separation by centrifugal casting to perform molding. The centrifugal cast molding machine used for centrifugal cast molding has the same configuration as the centrifugal separator, and puts the slurry into a container that becomes a mold, and at the time of centrifugal cast molding, a large centrifugal force is generated by increasing the rotation speed thereof. Since a slurry is produced and the slurry is solid-liquid separated by the centrifugal force to produce a molded body, a higher rotation speed is more effective, and the centrifugal force at the time of molding is 3000 G or more, preferably 5 G.
000G or more is required.

[0017]

According to the present invention, since the powder is molded by centrifugal casting, it is possible to easily manufacture a large molded body in an extremely short time. Further, since the amount of liquid contained in the obtained molded product is small, it is possible to easily produce a large dry molded product with little shrinkage and no cracking. It can be manufactured.

[0018]

EXAMPLES Examples of the present invention will be shown below and described in more detail. Example 1 0.5 wt% of polyvinyl alcohol as a binder
To the added aqueous solution, 70 wt% of monodisperse fine particle spherical silica having an average particle diameter of 0.5 μm was added, and sufficiently stirred to disperse the silica to prepare a uniform slurry. Next, the slurry is lengthwise 7
cm, width 25 cm, height 30 cm, filled up to a height of 25 cm, sealed, set on a centrifugal casting molding machine, and subjected to solid-liquid separation by centrifugal force 8000 G by high speed rotation, length 7 cm, width 25
A molded body having a height of 12 cm and a height of 12 cm was obtained. 50 to the obtained molded body
Drying was performed for 3 days at 100 ° C. and for 7 days at 100 ° C. to produce a crack-free dried body.

The dried product is heated in a degreasing furnace to 800 ° C. in a stream of oxidizing gas such as air or oxygen at a heating rate of 25 ° C./hr.
It is calcined to decarburize, then sintered under reduced pressure to a temperature of 1300 ° C at a heating rate of 50 ° C / hr, and has a length of 6 cm, a width of 21 cm and a height of 10 cm, and is a bubble-free high quality quartz The glass was manufactured.

Example 2 0.5 wt% of polyvinyl alcohol as a binder
Cerium chloride (heptahydrate) was dissolved in the added aqueous solution to a concentration of 10 ppm. Next, in the same manner as in Example 1, a silica-ceria glass was manufactured by molding using a centrifugal casting molding machine, calcination, and sintering. The obtained glass had a property of transmitting 70% of ultraviolet rays having a wavelength of 200 nm.

Comparative Example 1 0.5 μm with water containing no binder as a dispersion medium
70% by weight of fine spherical silica particles, and thoroughly stirred,
A uniform slurry was prepared by dispersion, and a molded body was manufactured by a centrifugal casting molding machine in the same manner as in Example 1.

When the obtained molded product was dried at 50 ° C., the molded product was cracked during the drying, and a large glass without cracks could not be obtained.

[0023]

Industrial Applicability As described above, according to the present invention, it is possible to easily produce various types of glass of large size, high quality and various kinds, regardless of single component or multicomponent, in a short time and at low cost. ..

Claims (4)

[Claims] 1. Particles, which are raw materials for glass, are dispersed in water or an organic solvent to which a binder is added to obtain a uniform slurry, and the slurry is subjected to centrifugal casting for solid-liquid separation.
After the molding, the molded body is dried, sintered, and vitrified, which is a method for producing glass. 2. The method for producing glass according to claim 1, wherein an organic polymer or a metal alkoxide hydrolyzate is used as the binder. 3. The method for producing glass according to claim 1, wherein at least one metal or non-metal compound is added to form a multi-component system. 4. The method for producing glass according to claim 1, wherein the raw material particles of glass are monodisperse particles having a uniform particle size.