JPS62123032A - Production of porous glass - Google Patents

Abstract

PURPOSE:An ultra-fine powder of silica is added to a sol solution of a metal alkoxide, then a polyvinyl emulsion is dispersed in the sol solution whereby a high-bulky porous glass of arbitrary pore sizes is readily obtained. CONSTITUTION:Hydrochloric acid is added to a metal alkoxide such as silicon ethoxide and they are stirred to effect hydrolysis. Then, an ultra-fine powder of silica is added to the sol solution under stirring, subsequently a polyvinyl emulsion such as polyvinyl acetate emulsion is dispersed in the sol solution. The sol solution is placed in a vessel, the vessel is tightly closed and left to stord effect gelling. Holes are bored in the vessel, dried by heating, the resultant gel is roasted to form a porous glass. At this time, the emulsion added to the sol is varied in its amount to control the number of the pores. The process according to the present invention enables the production of high-bulky, porous glass with arbitrary pore sizes and more than 5mm thickness.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing porous glass.

[Summary of the invention]

In the production of porous glass using the sol-gel method, the present invention involves dispersing a polyvinyl emulsion in a sol solution, drying, and sintering to decompose and evaporate organic substances, thereby producing porous glass. ! ! ! There are nine things that make it possible to create.

[Conventional technology]

The conventional method for manufacturing porous glass is disclosed in the Koni Glassworks patent (U, S, Pat 2.21503).
9, 2.221709), 47ill is made by melting boric acid, alkali metal oxide, silica sand, etc. as main raw materials.
Silicate glass is heat-treated at a temperature of several hundred degrees to cause phase separation.

This phase separation treatment separates the silica sand 11J (SzOa) into a glass phase and a gaseous phase rich in boric acid and alkali metal oxides.

Next, by treating this glass with an acid solution or hot water, a glass phase rich in boric acid and alkali metals is eluted.
This manufacturing method produced glass that was rich in silicic acid components and retained its original shape.

[Invention h; Problem to be solved]

However, in the prior art described above, the thickness is 100
The limit is about X 100 It is impossible to build. Especially when it comes to [PLl], when the thickness λ becomes more than 5u, it should be treated with acid solution or hot water1. In this case, the elution of the glass phase rich in boric acid and alkali metal components does not occur uniformly.

In addition, the above-mentioned conventional technology has the problem that only porous glass with non-uniform pore diameter in the thickness direction can be manufactured. In the case of bulk porous glass, the limit is tens of angstroms to several hundred angstroms. When the pore diameter becomes large, the bulk porous glass is more likely to break during production and is difficult to form into a large bulk.

The present invention is intended to solve these five problems, and its purpose is to provide a method for producing a large bulk porous glass having pores of several microns.

[Means for solving problems]

The method for producing porous glass of the present invention is characterized in that a polyvinyl emulsion is dispersed in a sol solution in a method for producing glass by a sol-gel method using a metal alkoxide as a raw material.

〔Example〕

Example 1゜Silicone etho-1t-cyto 250 ml K, 0.
Add 200% of 01N hydrochloric acid and stir vigorously for hydrolysis. Next, add ultrafine powdered silica to this solution (manufactured by Nippon Aerosil Co., Ltd., Aerosil OX 50. Surface area: 50 cm/9
) 100F while stirring and applying ultrasonic lift to ensure good dispersion. Subsequently, 10 to 50% by weight of polyvinyl acetate emulsion solution is added and well dispersed. After that, 0.1N ammonia water was added dropwise to the sol solution to adjust the pH value to 35~35.
Adjust to 6.6. This sol solution is placed in a polypropylene container (φ100×450 mm) so that the height is 2 to 3 cm. This container is sealed and stored at 20 to 30°C to form a gel. After that, make several holes in the container and
Dry at 0°C for 10 days to obtain a dry gel. Next, put the dry gel in an electric furnace and heat it for 1 hour at 500℃~1000℃.
The temperature was slowly raised to 0°C to evaporate the organic components, and then
A porous glass is obtained by sintering at 1100'C to 1200C. Table 1 shows the average pore diameter and specific surface area of the obtained porous glass.

Brush 1 Table Example 2゜Prepare a sol under the same conditions as Example 1゜/+i, Disperse polyvinyl chloride emulsion into the sol.

Thereafter, drying and sintering are performed in the same manner to obtain porous glass. The average pore diameter and specific surface area of the obtained porous glass are
Shown in the table.

Table 2 Example 5 200ml of 0.01N hydrochloric acid was added to 250ml of silicone butane and hydrolyzed by stirring vigorously. After adding and dispersing ultrafine powdered silica in the same manner as in Example 1,
Add and disperse 0 to 50% by weight of polyvinyl acetate emulsion. Thereafter, drying and sintering are performed in the same manner to obtain porous glass. The average pore diameter and specific surface area of the obtained porous glass are as follows. ! O shown in Table 3 Example 4゜Example 3. A sol is prepared under the same conditions as above, but the polyvinyl chloride emulsion is dispersed in the sol.

The molding, drying and sintering are performed in the same manner to obtain porous glass. The average pore diameter and specific surface area of the obtained porous glass are
Shown on clothing.

Table 4 Example 5 0.01 standard i
Add 200 ml of hydrochloric acid and stir vigorously for hydrolysis. Thereafter, as in Example t, ultrafine powdered silica is added and dispersed, and then a polyvinyl acetate emulsion of 10 to 5013@th is added and dispersed. Then dry.

Sintering is performed in the same manner to obtain porous glass. Table 75 shows the average pore diameter and specific surface area of the obtained porous glass. Prepare a sol under the same conditions as above, add a portion of polyvinyl chloride emulsion into the sol, and then dry and sinter in the same manner to obtain porous glass. The average pore diameter of the obtained porous glass is shown in Table 6 with a specific surface of 81.

Sixth Thorn [Effects of the Invention] As described above, according to the present invention, porous gas having a pore diameter of several microns can be produced; Bulk porous glass with a thickness of 51 or more! ! l! It has the effect that it is possible to create

By implementing the emulsion 1, it also has the effect that the number of pores can be controlled.

that's all

Claims (1)

[Claims] Sol made from metal alkoxide and ultrafine powdered silica
A method for producing porous glass characterized by dispersing a polyvinyl emulsion in a sol solution in producing glass by a gel method.