JPS58199736A - Manufacture of quartz glass - Google Patents

Abstract

PURPOSE:To prevent warping, cracking, etc. in the manufacture of quartz glass by a sol-gel method, by removing a solvent from the periphery of a container to dry silica gel. CONSTITUTION:The hydrolyzate of ethyl silicate is poured into a container 4 such as a laboratory dish, and the container 4 is covered with a flat plate 5 of glass, acrylic resin or the like with a spacer 6 in-between. After fixing the plate 5 with clips, the container 4 is placed in a dryer and allowed to stand at a constant temp. for a suitable time. The solvent is removed efficiently and uniformly from the periphery of the container 4, and dry gel is obtd. without causing cracking, warping, etc. By calcining the dry gel, the desired quartz glass is obtd. simply and inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing quartz glass, and more specifically, during drying of silica gel made by hydrolyzing alkyl silicate, the solvent is evaporated and removed from the periphery of the container, and then, This invention relates to a method for producing quartz glass by firing it into quartz glass.

Silica glass is a glass with excellent properties such as chemical resistance and heat resistance.

Because of these excellent properties, quartz glass is used in a wide variety of shapes as a material for optical equipment, physical and chemical instruments, and the chemical industry. Moreover, the demand is increasing year by year.

However, in the conventional manufacturing method of quartz glass called the fusion method, natural quartz or high-purity silica is used as a raw material, and it undergoes complicated processing steps such as washing with water, sorting, hydrofluoric acid treatment, roasting, and pulverization.
Finally, it requires a very long process of melting at a high temperature of about 2000°C, which has the disadvantage of being expensive. Furthermore, since the process is carried out at high temperatures, the amount of energy consumed is actually large.

On the other hand, recently, 100
The sol-gel method, which produces silica glass at a low temperature of about 0°C, is attracting attention. This sol-gel method is a method in which glass is obtained by drying, solidifying, and firing a silicic acid gel obtained by hydrolyzing ethyl silicate.

This sol-gel method has many advantages over conventional melting methods in obtaining high-quality glass, such as easier raw material purification and homogenization.

However, this sol-gel method has the disadvantage that large glasses cannot be obtained. One of the reasons why this cannot be obtained is as follows.

In the conventional sol-gel method, when making a dry gel, the container was covered with aluminum foil and holes such as pinholes were made to control the amount of evaporation.

However, this method did not produce good results because the aluminum foil was exposed to the hydrochloric acid catalyst, which changed the diameter of the holes. In addition, since the number of holes and the area of the holes are small relative to the container, it is not possible to uniformly control the amount of evaporation throughout the container.
Localized dryness may occur, causing cracking or flaking.

The object of the present invention is to provide means for improving these drawbacks.

Figure 1 shows the relationship between a conventional container and a lid.
1 is a container such as a petri dish, 2 is aluminum foil, and 3 is a pinhole.

As can be seen from the figure, if the amount of evaporation is controlled using a large pinhole, the amount of evaporation around the hole will increase, causing local drying and causing warping and cracking.

The manufacturing method of the present invention for this purpose will be explained with reference to FIG. In the figure, 4 indicates a container such as a petri dish, 5 indicates a flat lid made of glass, acrylic, etc., and 6 indicates a spacer.

Pour the hydrolyzate of ethyl silicate into the container shown in the figure, assemble the device as shown, fix it with clips, etc., and put it in a dryer and leave it at a constant temperature for an appropriate time to obtain a dry gel. , and then fired to obtain quartz glass.

As can be seen from the figure, according to the apparatus used in the production method of the present invention, the amount of evaporated solvent can be efficiently removed from the surroundings in a linear manner rather than in a dotted manner. For this reason, it can be expected that local drying will be eliminated and the phenomena of warping and cracking will be less likely to occur.

Embodiments of the present invention will be explained in more detail with reference to Examples below.

Example 1 Ethyl silica) 44.71. Ethanol 6 s L,
40 ml of α1N hydrochloric acid was placed in a flask and stirred and mixed for 3 hours to hydrolyze ethyl silicate.

After hydrolysis, this mixture was placed in a Petri dish with an inner diameter of 5 (1 m). Next, four pieces of 10μ silicone rubber were placed on the edge of the Petri dish, a glass plate was placed on top of the lid, and the mixture was heated at 60°C.
The mixture was left in a constant temperature bath until dry to form a dry gel. The resulting dry gel had a diameter of 35 was. Further, this dried gel was heated to a temperature of 13° C. and concentrated to 100° C. to form quartz glass.

The presence of quartz glass was confirmed using analytical means such as specific gravity, infrared IR spectrum, and hardness txmtm spectroscopy.

As described above, quartz glass can be manufactured easily and inexpensively by using the quartz glass manufacturing method of the present invention.

Therefore, it has come to be used in fields where it could not be used in the past due to its high price, and it exhibits great properties such as heat resistance and chemical resistance.

[Brief explanation of the drawing]

FIG. 1 shows a conventional apparatus for producing dry gel when producing quartz glass by the sol-gel method. In the figure, 1 is a petri dish and 2 is aluminum foil. 3 represents a pinhole. Figure 2 is a diagram of the apparatus used in the manufacturing method of the present invention, where 4 represents a petri dish, 5 represents a lid, and 6 represents a spacer.

Claims (1)

[Claims] A method for producing quartz glass in which silica glass is produced by hydrolyzing alkyl silicate and drying and firing silica gel, which method comprises removing the solvent from the periphery of the container and drying the silica gel when drying the silica gel. .