JPS6054931A - Mass-production of quartz glass plate - Google Patents

Abstract

PURPOSE:To enable the mass-production of quartz glass plate having high flatness, by manufacturing a thick dry gel by the sol-gel process from a metal alkoxide, and slicing the dry gel. CONSTITUTION:Ethyl silicate is hydrolyzed with an aqueous solution of hydrochloric acid, mixed with fine silica powder, dispersed uniformly, and adjusted to 4-6pH. The obtained sol is poured into a deep vessel having flat bottom, and gelatinized and dried under shrinkage to obtain a thick dry gel. The thick dry gel is sliced to a plurality of flat dry gel plates having the required thickness, and the sliced plates are sintered to obtain a plurality of flat quartz glass plates at the same time. Since the dry gel prepared by this process has large thickness, an easily sliceable thick gel having high flatness and resistant to warpage in drying can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing quartz glass by a sol-gel method using at least a metal alkoxide as a raw material. Regarding.

Quartz glass is used in crucibles and ports during the l0tJ manufacturing process.
Diffusion furnaces have come to be used at equal pressure, and their usefulness has been recognized.Those with less hydroxyl groups in yr and those with good optical uniformity have been developed.Thus, they are used for various optical purposes. It's like K. Detection, quartz glass fiber for optical communication, and T.

The power of quartz glass masks for use is attracting attention. In addition, a thin film transistor (TPT) substrate and 1. The use of flat quartz glass is also expanding, such as in silica glass masks and TPT substrates.

Flat quartz glass is generally manufactured by two methods. One method is to melt natural quartz and, more commonly, synthetic quartz to create a single rod.This method involves cutting the rod into rounds. The other method is to create a hollow cylindrical tube instead of a rod shape, and cut it open to make it into a flat plate.

In either method, the production temperature is high and the raw materials are expensive, so commercially available flat quartz glass is expensive. Due to these drawbacks of quartz glass, attempts have recently been made to manufacture quartz glass at low cost using a sol-gel method using metal alkoxides. Generally, methods for producing quartz glass using the sol-gel method can be divided into the following three types.

First, a metal alkoxide is hydrolyzed with an acid ll'fC under an alkali catalyst, gelled with a sol (12), dried, dried to form a dry gel (17), and sintered (12) to form quartz glass. One more thing, don't use metal alkoxide as a raw material.
The raw material is finely powdered silica. This is a process in which finely powdered silica is poured into water, turned into a hydrosil, gelled, and the dry gel and I2 dry gel are sintered to form quartz glass. The other type uses metal alkoxide and finely powdered silica as raw materials. This is done by adding finely powdered silica to a sol solution obtained by hydrolyzing metal alkoxide, adjusting it to FT (near total neutrality), leaving it to gel, drying it to form a dry gel, and then sintering it to form a quartz crystal. Among these methods, the most excellent method for producing bulk quartz glass is the method mentioned last, which uses metal alkoxide and finely powdered silica as raw materials. Although the 5φ light and the embodiments of the present invention are particularly based on this method (/-I), it is clear that the other two methods have similar effects.

As mentioned above, flat quartz glass generally has many uses, but it has the drawback of being expensive.

Therefore, an object of the present invention is to manufacture flat quartz glass at low cost! It is to provide a method for giving birth.

As a method, the following method is used as plan t. Ta. That is, by hydrolyzing hydrochloric acid water into ethyl silicate,
(Deggrtssa) and Cab-n-si
Add finely powdered silica, which is a white carbon such as (Ca) Ro-O Co., Ltd., and disperse it well and uniformly, and adjust the pH to 4 to 7.

The sol thus obtained is placed in a deep container with a flat bottom, gelled, and dried by shrinkage to obtain a thick plate-like dry gel. This thick plate-like dry gel is sliced into a plurality of flat dry gels having a required thickness, and these are sintered to simultaneously obtain a plurality of flat quartz glasses. Therefore, this method is a very effective means for manufacturing flat quartz glass plates in mass production, and it is also possible to produce a single quartz plate of the required thickness from a single piece of quartz glass without slicing. When manufacturing, the thickness of the target quartz plate is often thin, so the thickness of the dry gel is also thin. Curved dry gel tends to warp due to non-uniformity during drying or for various reasons, so if dry gel is sintered as it is, it becomes warped quartz glass, which is difficult to produce into a usable flat quartz glass. On the other hand, since the dry gel obtained by the method of the present invention is thick, it becomes a plate-like dry gel with good flatness and is very warped during drying, making it easy to slice.

The present invention will be described in detail below according to Examples.

Example 1 00 to purified commercially available ethyl silicate 624σ (3 mol)
Add 540 rnl of 2N hydrochloric acid aqueous solution and stir gently for hydrolysis. To this solution, 300 mt of water was added, and finely powdered silica (A, erosil ox s O: trade name of finely powdered silica with a surface area of 50 m" and 7 g manufactured by Aerosil Co., Ltd.) was added under stirring of 5-225σ, followed by dispersion using ultrasonic vibration, etc. This sol was filtered to remove dust, etc. 1. PH was adjusted to 5. OK by adding 1N ammonia water dropwise to this sol KO. .

This sol was placed in a deep box-shaped container (30 m x 20 G x 20 ports) made of polypropylene with a flat bottom to a depth of 6 G. Seal the lid and let it stand at room temperature for 30 minutes and gelation L7. Leave it for another day and night. Replace the t0 lid with one that has a hole in it so that the solvent can distill out. Leave it at 50-70°C to dry, and leave it for 7 days. A stable thick plate-like dry gel (21 cm x 14 crn x 46 In) was obtained which did not crack even after being left at room temperature. Slice this thick plate-like dry gel and
Six dry gel plates measuring crn x 14 cm x 04 cm were obtained. However, the cutting margin of the peripheral blade for slicing is 0.2
Because it was crn, we lost the amount of margin. The six plate-shaped dry gels obtained in this manner were heated slowly to 1,200°C in a sintering furnace, and left at 1,200°C for 1.5 hours to sinter, resulting in transparent and flat plate-shaped quartz glass ( 15crnX 10cmX 0.5cm 1 is 6
I got one.

6- It is clear that the method of the present invention is not limited to the sol-gel method using metal alkoxide and finely powdered silica as raw materials as in this example.

II mass production method of thick flat quartz glass with flat jf3 properties of the present invention, 7. TP because it is included in the price due to manufacturing.
It is believed that this will greatly contribute to various fields such as T substrates and TC masks.

Less than ten Applicant: *i8 Seikosha Co., Ltd. Fushirito Patent attorney 1st office 7- 173-

Claims (1)

[Claims] A sol containing at least metal alcohol A' as a raw material.
A method for synthesizing plate-shaped quartz glass at a low temperature by a gel method, which is characterized in that a large plate-shaped dry gel is created, and the dry gel is sliced to produce a large number of flat-shaped dry gels. ’l of shaped quartz glass! Method of birth.