JP2982352B2 - Method for producing flake glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple and efficient method for producing glass flakes using a solution containing an organometallic compound as a starting material. In the present invention, the term “flake glass” refers to glass flakes each having a length and width of 5 mm or less.

[0002]

2. Description of the Related Art Flake glass is currently used for plastic fillers, corrosion resistant linings or paints. Such flaky glass is mainly composed of soda-lime silicate glass and has a thickness of about 4 microns. Inflate the molten glass like a balloon, quench,
It is manufactured by grinding. There is a demand for a flake glass that is capable of withstanding higher temperatures, for example, by adding various materials to the inside of the flake glass to impart new performance, for example, but is conventionally difficult.

A technique for producing a thin glass plate from a solution containing an organic metal is disclosed in, for example, JP-A-51-34219 disclosed by Shinbo et al. Is floated on another liquid to form a thin glass. According to this published patent, a thin glass piece of 1 micron or less is obtained, and it can be inferred that crushed glass can be used to produce flake glass. Considering the production of flaked glass with this technology, there are problems such as difficulty in collecting glass pieces floating in water and difficulty in uniforming the film thickness. Have difficulty.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, the present invention provides a method for simply and efficiently producing thin flake glass which has not been conventionally produced. is there.

[0005]

Means for Solving the Problems In order to solve this problem,
The present inventors have already used a solution containing an organometallic compound as a starting material and applied it to a substrate, preferably a substrate having a smooth surface, dried and peeled from the substrate, and then sintered. Proposed a method of manufacturing flake glass characterized by the following,
As a result of extensive studies, the present inventors have found that flake glass can be produced more easily and efficiently by adding oxide fine particles to a solution containing an organometallic compound used in this production method. .

The organic metal compound as a raw material used in the present invention may be basically any compound as long as it undergoes hydrolysis and dehydration condensation, but a metal alkoxide having an alkoxyl group is preferred. More specifically, methoxide such as silicon, titanium, aluminum, zirconium, phosphorus, and boron, ethoxide, propoxide, and butoxide are used alone or as a mixture. Accordingly, the composition of the flake glass obtained according to the present invention may be, for example, pure silica, silicate-based, titanate-based, aluminate-based, zirconate-based, phosphate-based, borate-based amorphous. Or it is crystalline.

In the present invention, oxide fine particles are contained in a dispersed state in a solution containing an organometallic compound. The composition of the oxide fine particles is preferably the same as the composition of the oxide glass obtained from the organometallic compound in the solution. Depending on the method of producing the oxide fine particles, a very small amount of impurities may be mixed in, but they may be of the same composition. Further, it is also possible to add oxide fine particles that are significantly different from the composition of the oxide glass obtained from the organometallic compound, and to cause a reaction at the time of sintering to obtain an oxide glass having a uniform composition.

The oxide fine particles used in the present invention have a particle diameter of 1
What is necessary is just 0 angstrom or more and 5000 angstroms or less. Oxide fine particles smaller than 10 angstroms are difficult to stably exist. On the other hand, if it is larger than 5000 angstroms, it is difficult to disperse uniformly in a solution containing an organometallic compound, and at the time of coating, these fine particles settle and the composition does not become uniform, and pores disappear during sintering. No, etc. The content of the oxide fine particles is 10% by weight or more and 80% by weight at the time when the glass flakes are formed.
The following should be good. When the amount is less than 10% by weight, the effect of substantially adding the oxide fine particles, that is, the improvement in the releasability of the flaky gel is not remarkable, and when the amount is more than 80% by weight, the glass phase is not continuous and the flake glass is brittle. Is not preferred.

The method for producing the above-mentioned oxide fine particles is not particularly limited. Examples thereof include a method of reacting a gaseous organometallic compound with oxygen at a high temperature, a method of hydrolyzing a liquid organometallic compound, and a method of dehydration-condensation. Is exemplified. In consideration of the stability and dispersibility of the oxide fine particles, it is preferable to use the fine particles prepared in a liquid phase as a liquid or a colloid solution in a state of being dispersed in a dispersion medium as it is. The solvent of the raw material solution containing the organometallic compound and the oxide fine particles may be basically any solvent as long as it substantially dissolves the organometallic compound, but may be methanol, ethanol, propanol, or butanol.
Most preferred are alcohols such as alcohols. The amount of the solvent used is 0.1 to 0.995, preferably 0.2 to 0.9, more preferably 0.3 to 0.85 by volume ratio with respect to the total amount of the organometallic compound and the solvent. is there.

The hydrolysis of the organometallic compound as the raw material requires moisture. This may be neutral, acidic, or basic, but in order to promote hydrolysis, it is preferable to use water acidified with hydrochloric acid, nitric acid, sulfuric acid or the like. The amount used is 1 mol of water to 1 mol of the organometallic compound.
A range of 00 moles is preferred. The amount of the acid used is 0.01 to 2, preferably 0.05 to 1.5, in a molar ratio to the organometallic compound. In addition, an organic thickener or the like may be added to the solution to change the characteristics of the raw material solution, for example, to adjust the thickness of the solution applied to the substrate. However, if this addition amount is large, carbides may remain on the thin film due to heating in the final stage, so that 10 w
It should be less than t%.

The substrate used in the present invention is made of a material such as metal, glass or plastic and has a smooth surface. A liquid containing the organometallic compound and the oxide fine particles is applied to such a base material to form a thin liquid film having a thickness of 0.06 to 50 μm. The film shrinks when dried, but the substrate does not shrink, so that the film cracks and becomes flake-like. In order for the separation between the substrate and the film to occur, it is preferable that the bonding between the substrate and the film cannot be performed. The technique of forming a film on the surface of the base material may be a known technique, for example, a method of immersing the base material in a solution containing the organometallic compound and then pulling the base material, or dropping the solution on the base material, A method of rotating the substrate at a high speed is used. The thickness of the glass flakes produced in the present invention varies depending on the solution or the conditions at the time of film formation.
Between 5 microns. If the thickness is larger than this, the difference in the drying speed between the free surface and the vicinity of the base material becomes too large, and peeling between the films in the direction parallel to the base material occurs. Conversely 0.0
If the thickness is less than 5 microns, the adhesion between the substrate and the film becomes too large, and the film does not peel off from the substrate and does not become flakes.

Regarding sintering, the method is not particularly limited. It is desirable to heat the sintering temperature and time above conditions that ensure the transition from gel to glass,
Usually, heating is performed at 300 ° C to 1200 ° C for 10 minutes to 2 hours. Depending on the purpose of use, sintering after drying may not be required.

[0013]

Examples are shown below. Example 1 20 ml of 0.1 N nitric acid was gradually dropped into 100 ml of commercially available silicon tetramethoxide, and then commercially available colloidal silica (trade name: Snowtex-O, silica content: about 20% by weight, particles 200 ml (100-200 Å diameter) were added. This was kept at 40 ° C. for 24 hours to advance the reaction, and then returned to room temperature. The obtained liquid was diluted with an equal amount of isopropyl alcohol to obtain a coating solution. A 1-mm-thick stainless steel plate whose surface was polished and smoothed was immersed in this, and pulled up at a speed of 30 cm / min. After being left to dry in the air and then placed in a dryer at 120 ° C. together with the stainless steel substrate, film peeling occurred almost instantaneously on the entire surface of the substrate. Put this gel film in alumina crucible,
Sintered at 1100 ° C. for 1 hour. After sintering, when examined by an X-ray diffraction method, no sharp peak was recognized and the glass was in a glassy state. Observation with an electron microscope revealed that the film was a flaky glass having a thickness of about 0.5 μm.

Example 2 Silicon tetramethoxide 100 ml, ethanol 100
The mixture was stirred at about 30 ° C., and 100 ml of 1N aqueous ammonia was gradually added dropwise. Immediately after the addition of the aqueous ammonia, silica fine particles precipitated in the solution and gradually became cloudy. After the stirring was continued for 24 hours while maintaining the temperature at 30 ° C., the pH was adjusted to 3 using 1N nitric acid. A part of the colloid solution was collected, and the dispersed fine particles were observed with an electron microscope. As a result, the average particle diameter was 4,200 angstroms. Add 5 new to this colloid solution
00 ml of isopropyl alcohol and 100 ml of silicon tetramethoxide were added and stirred at room temperature for about 4 hours.

This solution was prepared under the same conditions as in Example-1.
It was applied to a stainless steel substrate, dried, and the flake gel was peeled off. This flaky gel was white. This was placed in an alumina crucible and sintered at 1000 ° C. for 2 hours to obtain a transparent flake glass. After sintering, when examined by X-ray diffraction, no sharp peak was observed.
It was in a glass state. Observation with an electron microscope revealed that the film was a flaky glass having a thickness of about 0.6 μm.

COMPARATIVE EXAMPLE 1 In Example 1, commercially available colloidal silica 2 was added.
100 ml of silicon tetramethoxide and 0.1 ml of silicon tetramethoxide.
A solution was prepared by substituting and adding 100 ml of normal hydrochloric acid.
That is, this solution has substantially the same silica concentration as in Example 1, but does not contain silica fine particles. When this solution was applied to a stainless steel substrate under the same conditions as in Example 1 and dried, the peeling from the substrate was only about 60% of the entire area, and the other parts were completely adhered to the substrate. It could not be peeled off.

Comparative Example 2 The conditions for preparing the colloidal solution of Example 2 were set at 40 ° C. for 72 hours. When the average particle size of the obtained silica fine particles was observed with an electron microscope, it was 8,500 Å. Using this colloid solution, a flaky gel was obtained under the same conditions as in Example-2. The appearance of the obtained flaky gel was white. Put this in an alumina crucible and add
Sintering was performed at various temperatures from 00 ° C to 1200 ° C. However, at any temperature, it did not become transparent and remained white. Further, when examined by an X-ray diffraction method, it was found that crystallization occurred at 1100 ° C. or higher.

Example 3 20 ml of 0.1 N nitric acid was gradually dropped into 100 ml of commercially available silicon tetramethoxide, and then commercially available colloidal zirconia (trade name, manufactured by Nippon Shokubai Chemical Industry Co., Ltd.)
Zirconia amorphous sol, zirconia content about 27
200% by weight). This was kept at 40 ° C. for 24 hours to advance the reaction, and then returned to room temperature. The obtained liquid was diluted with an equal amount of isopropyl alcohol to obtain a coating solution. A 1-mm-thick stainless steel plate whose surface was polished and smoothed was immersed in this, and pulled up at a speed of 30 cm / min. After being left to dry in the air and then placed in a dryer at 120 ° C. together with the stainless steel substrate, film peeling occurred almost instantaneously on the entire surface of the substrate. Put this gel film in alumina crucible,
Sintered at 1000 ° C. for 1 hour. After sintering, when examined by an X-ray diffraction method, no sharp peak was recognized and the glass was in a glassy state. Observation with an electron microscope revealed that the film was a zirconia-containing flake glass having a thickness of about 0.5 μm.

[0019]

According to the present invention, by adding oxide fine particles to a solution for applying an organometallic compound to a substrate,
The solution is less reactive and therefore less interacting with the substrate, resulting in less adhesion between the dried film and the substrate. By using this solution, the removability of the flaky gel from the substrate can be improved, and the flaky glass can be easily and efficiently produced.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-922832 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C03B 37/00-37/16

Claims (4)

(57) [Claims] 1. A method for producing a flake glass by applying a solution containing an organometallic compound onto a substrate, drying the same, and exfoliating the substrate from the substrate, and sintering the solution. A method for producing flaky glass, comprising dispersing fine particles. 2. The method according to claim 1, wherein the oxide fine particles have the same composition as an oxide obtained from the organometallic compound. 3. The oxide fine particles have a diameter of 10 to 5000 angstroms.
A method for producing the flaky glass according to the above. 4. The addition amount of the oxide fine particles is 10 to 80% by weight of the flaked glass after sintering.
4. The method for producing flake glass according to any one of claims 1 to 3.