JPH085679B2 - Quartz glass manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing quartz glass by a sol-gel method.

[Conventional technology]

A conventional method for producing quartz glass by a sol-gel method is, as described in detail in Japanese Patent Application No. 58-237577, after uniformly dispersing ultrafine silica powder in a hydrolyzing solution of a metal alkoxide, It has a step of charging a sol solution in which the PH value of the dispersion liquid is adjusted to 3 to 6 into a container, gelling, drying and sintering.

By using this method, one glass body can be obtained from one charged gel, and by polishing flat glass, it can be applied to a photomask quartz substrate for IC, etc., and is an effective method as a manufacturing method by the sol-gel method. is there.

[Problems to be solved by the invention]

However, with the conventional manufacturing method,
Only one glass body can be obtained, considering mass productivity,
It is extremely irrational.

Therefore, the present invention solves the conventional problems of mass productivity, and an object thereof is to obtain two or more glass bodies simultaneously from one charging container to improve mass productivity. is there.

[Means for solving problems]

The method for producing quartz glass of the present invention comprises a step of adjusting a sol solution containing an alkyl silicate, a gelation step, a drying step,
In the method for producing quartz glass by the sol-gel method having a step of sintering the gel, after the pH-adjusted sol solution is gelled in the container, the pH-adjusted sol solution is further charged on the gelled solution. , Two or more layers of gelled wet gel are obtained, then the wet gel is dried and peeled layer by layer to obtain two or more dry gels, and then the dry gels are sintered to form two or more quartz glasses. Characterized by getting the body.

Example 1 An aqueous solution obtained by adding 3.2 ml of hydrochloric acid to purified commercially available purified ethyl silicates 1.94 and 3.2 was stirred vigorously to obtain a colorless transparent uniform solution. 975 g of ultrafine silica powder (trade name: Kyabosil L-90, manufactured by Kyabotsu) was gradually added thereto and sufficiently stirred. Furthermore, ultrasonic waves are applied to this sol solution for 3 times.
Irradiated for an hour. A centrifugal force of 1500 G was applied to the sol solution for 15 minutes to remove the lumps in the sol solution to obtain a sol solution having high homogeneity.

The sol solution was adjusted to pH 4.3 with 0.1 N ammonia water, and then a polypropylene container (width 30 cm x 30 cm x height 10
cm) was charged with an amount of 750 ml and the lid was placed horizontally.
Since gelation occurred after about 1 hour, 750 ml of a sol solution adjusted to pH 4.3 again was poured onto the solidified gel and allowed to stand horizontally. After about 1 hour, gelation occurred, and a two-layer wet gel was obtained. The wet gel was aged for 5 days in a thermostatic chamber at 30 ° C.

Cover the aged wet gel with a 0.4% open area lid.
It was dried in a drying chamber at ℃. After about 22 days, the drying was completed.
Although the obtained dry gel had two layers, it was easily peeled off layer by layer by applying a little force.

The dry gel was placed in a gas displacement furnace and heated to 700 ° C. at a rate of 30 ° C./hr. Pure helium gas from 700 ℃ 1
It begins to flow into the furnace at a flow rate of / min and reaches 140 at a rate of 30 ° C / hr.
The temperature was raised to 0 ° C, and the temperature was maintained at 1400 ° C for 2 hours.

The obtained quartz glass is 14.6 cm wide x 14.6 cm x 3.2 mm thick.
Was the size of.

Example 2 A sol solution having the same composition as in Example 1 was prepared and gelled in three layers in the same gelling manner as in Example 1.

The wet gel was aged for 5 days in a thermostatic chamber at 30 ° C., then covered with a lid having a porosity of 0.4% and dried in a drying chamber at 58 ° C. Drying was completed after about 25 days. Although the obtained dry gel had three layers, it was easily peeled off layer by layer without cracking by applying a little force.

By sintering the dry gel in the usual way, the width
Quartz glass having a size of 14.6 cm × 14.6 × thickness 3.2 mm was obtained.

Example 3 An aqueous solution prepared by adding 11.1 ml of hydrochloric acid to purified purified ethyl silicate 4.6 and 11.1 pure water was vigorously stirred to obtain a colorless transparent homogeneous solution. 3.75 Kg of ultrafine silica powder (trade name Aerosil 0x50, Degussa Co.) was gradually added thereto and stirred sufficiently. Further, this sol solution was irradiated with ultrasonic waves for 3 hours to ensure the dispersion of ultrafine silica powder. A centrifugal force of 1500 G was applied to the sol solution for 15 minutes to remove the lumps in the sol solution to obtain a sol solution having high homogeneity.

The sol solution was adjusted to pH 4.3 with 0.1 N ammonia water, and then a polypropylene container (width 30 cm x 30 cm x height 10
cm) was charged with an amount of 750 ml and the lid was placed horizontally.
It gelled after about 50 minutes, so after applying a mold-releasing silicone spray (KF96SP. Shin-Etsu Chemical), 750 ml of a sol solution adjusted to PH 4.3 was poured again on the fixed gel and left standing horizontally. It gelled after about 50 minutes, so after applying a silicone spray for mold release, sol solution 750 adjusted to PH 4.3 again
ml was poured onto the solidified gel and left horizontally. After about 1 hour, the gel was formed, and a three-layer wet gel was obtained. The wet gel was aged for 5 days in a thermostatic chamber at 30 ° C.

Cover the aged wet gel with a 0.4% open area lid.
It was dried in a drying chamber at ℃. Drying was completed after about 25 days.
The obtained dry gel had three layers, and one layer had already peeled off at the time when the drying was completed.

By sintering the dry gel in the usual way, the width
A quartz glass having a size of 15 cm × 15 cm × thickness of 3.4 mm was obtained.

Example 4 A sol solution having the same composition as in Example 3 was prepared, and the same gelling method as in Example 3 was used to gel five layers.

The wet gel was aged for 5 days in a thermostatic chamber at 30 ° C., then covered with a lid having a porosity of 0.4% and dried in a drying chamber at 58 ° C. After about one month, the drying was completed. Five dry gels were obtained in a peeled state.

By sintering the dry gel in the usual way, a width of 15
A quartz glass having a size of cm × 15 cm × thickness of 3.4 mm was obtained.

Example 5 Commercially available purified ethyl silicate, commercially available ethanol,
29% ammonia water of water and commercial electronics grade are mixed with 11,16.8,3.8,0.45,
After vigorous stirring for 4 hours, the mixture was allowed to stand overnight in a cool and dark place to concentrate the silica fine particle dispersion liquid, and for stabilization, the PH value was adjusted to 4 to obtain the first liquid. When the average particle size of the silica fine particles was measured with a light transmission type centrifugal sedimentation particle size distribution measuring device, it was 0.40.
μm.

Next, commercially available purified ethyl silicate 4.8 and 0.02N hydrochloric acid 6.15 were mixed and stirred vigorously to carry out a hydrolysis reaction to obtain a second liquid.

Mix the 1st and 2nd liquids and add 0.1N ammonia water to P.
After adjusting to H4.3, 5 layers were prepared and gelled as shown in Example 4.

The wet gel was aged for 5 days in a thermostatic chamber at 30 ° C., then covered with a lid having a porosity of 0.4% and dried in a drying chamber at 58 ° C. After about one month, the drying was completed. Five dry gels were obtained in a peeled state. The dry gel was sintered by an ordinary method to obtain a quartz glass having a size of width 15 cm × 15 cm × thickness 3.4 mm.

〔The invention's effect〕

As described above, according to the present invention, in the method for producing a quartz glass by the sol-gel method having a step of adjusting a sol solution containing an alkyl silicate, a gelling step, a drying step, and a sintering step of the gel, After the adjusted sol solution is gelled in the container, the pH adjusted sol solution is further charged on the gel to obtain a wet gel gelled in two or more layers, and then the wet gel is Dry and peel into layers to obtain two or more dry gels,
After that, since the dry gel is sintered to obtain two or more quartz glass bodies, it is possible to obtain two or more glass bodies at the same time from one charging container, and the number of dried sheets within a limited drying space can be obtained. Has increased, resulting in a great effect on mass productivity.

Claims (1)

[Claims] 1. A method for producing quartz glass by a sol-gel method, which comprises a step of preparing a sol solution containing an alkyl silicate, a step of gelling, a step of drying, and a step of sintering the gel,
After gelling the pH-adjusted sol solution in the container, further charge the pH-adjusted sol solution to gel it,
A wet gel gelled by stacking two or more layers is obtained, then the wet gel is dried and peeled layer by layer to obtain two or more dry gels, and then the dry gels are sintered to obtain two or more quartz glass bodies. A method for producing quartz glass, which comprises: