JPS638186B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a surface treatment method for preventing components contained in solid materials such as glass, metals, and ceramics from oozing out from the surface and contaminating substances that come into contact with the materials. It is related to.

Containers and instruments used in semiconductor manufacturing, pharmaceutical manufacturing and storage, analytical operations, etc., such as containers for photoresist materials, glass bottles for reagents,
When using pharmaceutical glass bottles, ampoules, beakers, flasks, etc., it is necessary to avoid contamination of the chemicals handled by impurities, particularly alkali metals, leaching from the materials. Particularly in the production of semiconductors, the inclusion of even a very small amount of alkali ions poses an important problem as it greatly affects the characteristics of the produced semiconductor.

Until now, containers for handling chemicals have often been made of soda-based glass materials, but these containers are soaked in a chromic acid-sulfuric acid mixture or strong alkali for several days to thoroughly remove impurities from the surface. Even after careful cleaning using methods such as elution, a small amount of impurities could not be avoided.

For this reason, when contaminating impurities is particularly important, materials such as Pyrex glass and quartz that elute impurities with little elution, or materials with a protective coating such as Teflon on the surface are used, but these materials are expensive. Therefore, it is unsuitable for industrial implementation. Therefore, using cheap raw materials,
There has been a great need for a method that can simply and effectively prevent impurities from oozing out from the surfaces of containers and utensils.

The inventors of the present invention have conducted extensive research in order to meet these demands, and have found that by using a special coating liquid to form a silicon oxide film on the surfaces of conventionally commonly used containers and utensils, it is possible to easily The inventors have discovered that the object can be achieved, and based on this knowledge, the present invention has been completed.

That is, according to the present invention, a coating solution obtained by reacting a mixture of 1 mole of alkoxysilane, 2 to 5 moles of water, and 3 to 30 moles of alcohol is applied to the surface of a solid containing an exudable component, and then By heating to a temperature of 150° C. or higher to form a silicon oxide film, exudable components contained in the solid can be effectively prevented from exuding from the surface.

In the present invention, the coating liquid includes alkoxysilane,
A reaction mixture is obtained by mixing water and alcohol and adding a reaction accelerator therein to cause a reaction. Examples of the alkoxysilane include tetramethoxysilane, monomethyltriethoxysilane, tetraethoxysilane, monoethyltriethoxysilane, Tetrapropoxysilane, tetrabutoxysilane,
Examples include tetraphenoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, etc., and examples of alcohol include monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, and amyl alcohol. In addition, reaction accelerators include hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, hydrogen bromide, perchloric acid, phosphoric acid, boric acid, gold chloride, zinc chloride, aluminum chloride, iron chloride, copper chloride, nickel chloride, Chromium chloride, arsenic chloride, antimony chloride, tin chloride, silicon chloride, gallium chloride, indium chloride, platinum chloride, titanium chloride, copper sulfate, zinc sulfate, lead nitrate, zinc nitrate, aluminum nitrate,
Examples include iron nitrate, copper nitrate, nickel nitrate, indium nitrate, boron oxide, phosphorus pentoxide, and arsenic trioxide.

The ratio of each component used at this time needs to be in the range of 2 to 5 moles of water and 3 to 30 moles of alcohol per mole of alkoxysilane. In addition, the amount of reaction accelerator added is based on the alkoxysilane.
A range of 0.001 to 20% by weight is preferred.

This reaction is exothermic and alkoxysilane is hydrolyzed to produce hydroxysilane.

The reaction mixture thus obtained is further added with an organic solvent as necessary to adjust the concentration to 1 to 20% by weight in terms of silica, and after passing through a 0.2 to 1.0μ filter, it is used as a coating liquid. use.

Any organic solvent may be used as long as it can dissolve each component and can be applied uniformly to the surface of the substrate during coating, including alcohols, esters, ketones, etc.
Polyhydric alcohols and their ethers, β-diketones, or mixtures thereof are suitable; examples of alcohols include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, and amyl alcohol; examples of esters include acetic acid, etc. Ketones include methyl, ethyl acetate, propyl acetate, butyl acetate, etc.
Examples of polyhydric alcohols and their ethers include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol monomethyl ether. Examples include glycol monobutyl ether, ethylene glycol dibutyl ether, propylene glycol, and glycerin.

Suitable containers for applying the coating solution of the present invention include glass, ceramics, mica, inorganic materials such as stainless steel, and plastics, and shapes such as bottle, flask, cylindrical, and spherical. There are no restrictions.

In the present invention, in order to apply the coating liquid to the container, the dipping method, the spraying method, the pouring method,
This can be done using a conventional method such as brush painting.

After the coating is applied in this manner, the solvent is usually dried in the air to evaporate and a hydroxysilane film is formed, and when left to stand, the hydroxysilane decomposes and becomes mostly a silicon oxide film.

Next, this is further heat treated at a temperature of 150°C or higher. Since a higher heating temperature yields a harder film, it is desirable to conduct the heat treatment at as high a temperature as possible, taking into consideration the heat resistance of the container used. The longer the heating time, the better, but from the viewpoint of workability, the heating time should be 10~
60 minutes is preferred. Additionally, if a glass forming agent such as phosphorus pentoxide or boron oxide is added to the coating solution in an amount of 10% by weight or less based on the final SiO ₂ produced, the vitrification softening point will be lowered, making it possible to lower the heating temperature. can.

By carrying out the present invention, the inner wall of the container
A continuous film with a film thickness of 0.1 to 1.0 μ and no pinholes.
In addition, a highly pure coating can be formed easily and economically, and the elution of impurities into chemicals can be prevented, which is extremely advantageous industrially.

Next, the present invention will be explained in more detail with reference to Examples.

Example 209 g of ethyl orthosilicate, 5.4 g of water, and 572 g of ethyl alcohol were mixed, and 0.5 g of 35% hydrochloric acid was added thereto. When the mixture was stirred well and reacted, heat was generated and the reaction proceeded. After being left at room temperature for 3 days, the presence of a large amount of hydroxysilane was confirmed.

Solid concentration of this reaction solution (heated at 140℃ for 3 hours)
was 9.0% by weight. Acetone was added to the reaction solution to adjust the solid content concentration to 8.0% by weight, and the mixture was filtered through a 0.45 μm filter to produce a coating solution. A glass substrate (size 80×
120 mm, thickness 0.7 mm) by dipping and pulling up at a pulling speed of 30 cm/min, dried at 100°C for 15 minutes, and then baked at 500°C for 60 minutes to form a silicon oxide film with a thickness of 0.15 μm. The glass substrate on which the silicon oxide film obtained in this way was formed and the glass substrate on which no silicon oxide film was formed for comparison were washed with 5% hydrochloric acid for 5 minutes, and then separately washed with 10% hydrochloric acid.
A leaching test was performed by placing the sample in a container containing an aqueous hydrochloric acid solution and immersing it at 60°C for 10 minutes. When the leached Na content was measured by atomic absorption spectrometry, it was 0.01 ppm for the glass with the silicon oxide film of the present invention, and was 0.01 ppm for the comparative glass without the silicon oxide film.
It was 0.34ppm.

Claims (1)

[Claims] 1. A coating solution obtained by reacting a mixture of 1 mole of alkoxysilane, 2 to 5 moles of water, and 3 to 30 moles of alcohol is applied to the surface of a solid containing an exudable component, and then heated to a temperature of 150°C or higher. A method for preventing leaching of contained components from a solid surface, characterized by forming a silicon oxide film.