JPS6369724A - Production of glass - Google Patents

Abstract

PURPOSE:To produce a large-sized glass with good yield, by adding a basic reagent to a specified alkylsilicate to prepare a sol, gelling the prepared sol, then drying and sintering the obtained wet gel. CONSTITUTION:The wet gel is obtained by adding ethyl alcohol, water and a basic reagent (e.g. aq. ammonia) as a catalyst for a reaction to alkylpolysilicate oligomer such as a dimer - octamer of alkylsilicate as alkylsilicate, mixing, pouring into the container and gelling. Then the dried gel obtained by drying the wet gel is sintered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing glass by a sol-gel method.

[Conventional technology]

In the conventional production of glass using the sol-gel method,
Usually, an alkyl silicate monomer is used as a raw material, and this is subjected to a hydrolysis reaction using an acidic or basic catalyst to prepare a sol, which is then gelled, dried, and sintered to produce glass. [Problems to be Solved] However, with the above-mentioned conventional technology, it is extremely difficult to produce porous gel, and cracks occur during shrinkage drying and sintering, making it impossible to produce large-sized glass. Therefore, the present invention is intended to solve these problems, and its purpose is to provide a method for manufacturing large-sized glasses with good yield by the sol-gel method.

[Means for solving problems]

In the production of glass by the sol-gel method in which a sol is prepared using an alkyl silicate as the main raw material, this is gelled to produce a wet gel, and then the wet gel is dried and sintered. It is characterized by using an alkyl polysilicate oligomer of ~octamer and using a basic reagent as a reaction catalyst.

[For production]

According to the present invention, since a multimeric alkyl silicate is used as a starting material, this becomes the minimum unit of the skeleton of the gel structure, and it is easier to form a porous structure than when a normal monomer is used as the minimum unit. Therefore, it is less likely to break during drying and sintering after gelation, making it possible to produce large-sized glass.

〔Example〕

Example-1 Commercially available ethyl silicate (trade name: ethyl silicate 4)
0 (Colcoat Co., Ltd.) tetra-hexamer) 1, OO, 0
Mix 1500 ml of ethyl alcohol, 200 d of water, and 5 g of 1N ammonia water, stir, and when it becomes a transparent and homogeneous solution, add 90 od of each to a size of 30×
The mixture was poured into three 30×15 (cm) rectangular containers and sealed with lids, and gelatinized after 20 to 30 minutes. After that, it was left to stand in a sealed state for a day and night, then the lid was made with a 2% porosity, put in a dryer, raised from room temperature to 70°C in 1 hour, and then kept at 70°C. It was kept for 5 days until drying was completed. The dried gel prepared here is
Size: 24 x 24 x 0.8 (cJ type, weight: about 602 mm, no cracks, etc.) These three dried gels were put into a sintering furnace and heated at 60°C/hr.
S When heated and sintered at three different heating rates of 300°C/hr, 1150°C and 1
The size of the glass is 12.8 x 12.8
The weight was approximately 1,449, and the product was perfect with no cracks or cracks occurring during sintering.

The results of physical property analysis of the glass produced in this way matched those of fused silica glass, including Vickers hardness, specific gravity, coefficient of thermal expansion, infrared absorption spectrum, near-infrared absorption spectrum, and refractive index. No impurities were detected.0 Example-2 Commercially available ethyl silicate (trade name: ethyl silicate 4)
0 (Colcoat Co., Ltd. tetra-hexamer) toooi, 1.500 d of ethyl alcohol, 200 d of water and 2 nd of 1N ammonia water were mixed and stirred, and when the solution became transparent and homogeneous and became slightly cloudy, each When 900 d of the mixture was injected into three rectangular containers each measuring 30 x 30 x 15 (cm) and sealed with lids, the mixture turned into a gel after 5 to 10 minutes. After that, leave it in a sealed state for a day and night,
The lid was made with a porosity of 2%, placed in a dryer, raised from room temperature to 70°C in 1 hour, and then kept at 70°C.
Drying was completed within 4 days. The dried gel prepared here has a size of 25.5 x 25.5 x O.

ss (cm) weight was about 1602, and no cracking occurred.O These three dried gels were put into a sintering furnace in the same manner as in Example-1, and heated at 60°C/hr%, 180°C/hr, and 300°C.
When heating and sintering was performed at three different heating rates of / hr, the results were 1180°C, 1200°C, and 1200°C for each heating rate.
It was turned into transparent vitrification at 1220°C. The size of the glass is
12.8 x 12.8 x O, 40 (Cm) Weight 1
The glass was about 40f, and it was a perfect product with no cracks or breaks during sintering.The results of physical property analysis of the glass produced in this way were Vickers hardness, specific gravity, coefficient of thermal expansion, redness, etc. The external absorption spectrum, near-infrared absorption spectrum, and refractive index matched those of fused silica glass, and no impurities were found in the purity analysis. Compared to the conventional sol-gel method, cracking during drying and sintering after gelation is significantly reduced, and large glasses can be produced with high yield. Therefore, of course, in fields where quartz glass has been used up until now, IC
It is thought that it will be applied to a variety of uses, such as photomask substrates and base materials for optical fibers. Furthermore, A, 9, Ti, G
e %NIL% Oas By adding various elements such as Mg1Li and Te during sol preparation, it is easy to create multi-component high quality glasses with various properties.

Claims (1)

[Claims] 1) In the production of glass by the sol-gel method, in which a sol is prepared using an alkyl silicate as the main raw material, the sol is gelled to produce a wet gel, and then the wet gel is dried and sintered. , a method for producing glass characterized by having the following conditions. a) A dimer to octamer alkyl polysilicate oligomer is used as the raw material alkyl silicate. b) A basic reagent is used as a reaction catalyst.