JPH0477326A - Flaky glass and its production - Google Patents

Abstract

PURPOSE:To change the compsn. in a thickness direction by applying a 1st soln. contg. an org. metal compd. on a base plate and drying the coating, then applying a 2nd soln. contg. an org. metal compd. of the compsn. different from the compsn. of the 1st soln. thereon and drying and sintering the coating. CONSTITUTION:The org. metal compd. consisting of metal alkoxide, such as silicon tetramethoxide, is dissolved in alcohols, such as ethanol, and acidic water added with hydrochloric acid, etc., is dropped into the soln. to hydrolyze and further an org. thickener, etc., are added to the mixture to prepare the 1st soln. The org. metal compd. consisting of metal alkoxide, such as titanium isopropoxide, is dissolved in the alcohols, such as ethanol and the org. thickener is added thereto to prepare the 2nd soln. The 1st soln. is thereafter applied at 0.05 to. 5mum thickness on the base plate which consists of metals, glass or plastics and the surface of which is smoothed by polishing. The coating is dried. The 2nd soln. is then applied on this thin film and is dried. The coating is thereafter vitrified by sintering. The flaky glass consisting of the plural layers having the glass compsns. varying in the thickness direction is thus obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention provides a technique for easily and efficiently producing glass flakes having compositional changes in the thickness direction using a solution containing an organometallic compound as a starting material. Incidentally, the term "flake glass" as used in the present invention refers to a glass thin piece having a length and a width of 5II1 m or less, respectively.

[Conventional technology]

Currently, glass flakes are used in plastic fillers, corrosion-resistant linings or paints. Most of such glass flakes are composed of soda lime silicate glass and have a thickness of about 4 microns. It is manufactured by blowing up molten glass like a balloon, rapidly cooling it, and crushing it. With the development of industry, there is a demand for more highly functional glass flakes, but conventional methods have limitations. A technique for producing a thin glass plate from a solution containing an organic metal is, for example, as described in Japanese Patent Application Laid-open No. 34219/1983 disclosed by Shinbo et al. A known method is to make thin glass by floating it on a liquid. According to this published patent, 1
It is said that thin glass pieces of less than a micron can be obtained.
It can be inferred that by crushing this, it is possible to produce glass flakes. However, when considering producing glass flakes using this technique, there are drawbacks such as: (1) It is difficult to collect glass pieces floating in water; (2) It is difficult to obtain a uniform film thickness. It may be necessary to impart different physical or chemical properties to the surface and inner layer of the glass flake, for example by making the surface and inner layer of the flake have different refractive indexes. It was difficult to obtain.

[Problem to be solved by the invention]

In view of the above-mentioned prior art, the present invention provides a method for easily and efficiently manufacturing thin glass flakes having compositional changes in the thickness direction, which could not be manufactured conventionally. .

[Means to solve the problem]

In order to solve this problem, the present invention is characterized in that a solution containing an organometallic compound is used as a starting material, applied to a substrate with a smooth surface, dried, and then sintered. With this method, thin glass flakes can be easily and efficiently mass-produced, which was not possible using conventional techniques. At this time, by preparing a plurality of solutions that grow different organometallic compounds and sequentially applying them to the substrate, it is possible to manufacture glass flakes having compositional changes in the thickness direction. The organometallic compound used in the present invention may basically be any compound as long as it undergoes hydrolysis and dehydration condensation, but metal alkoxides containing an alkoxyl group are preferred. More specifically, methoxides, ethoxides, propoxides, butoxides of phosphorous, titanium, aluminum, zirconium, etc. are used alone or as a mixture. The solvent for the solution containing the organometallic compound may be basically any solvent as long as it substantially dissolves the organometallic compound, including methanol, ethanol, propatool,
Alcohols such as butanol are most preferred. Moisture is required for hydrolysis of the organometallic compound. This water may be either acidic or basic, but in order to promote hydrolysis, it is preferable to use water made acidic with hydrochloric acid, nitric acid, sulfuric acid, or the like. In addition, an organic thickener or the like may be added to change the properties of the liquid. However, if the amount added is too large, carbonization may occur during heating in the final stage, so it should be kept at 10% or less. The substrate used in the present invention is made of a material such as metal, glass, or plastic, and has a smooth surface. Applying a liquid containing the organometallic compound to such a substrate,
Make it a thin film. When this film dries, it shrinks, but the substrate does not, so the film cracks and becomes flaky. In order for peeling between the substrate and the film to occur, it is preferable that the bond between the substrate and the film cannot be formed. A known technique may be used to form a film on the substrate, such as a method in which the substrate is immersed in a solution containing the organometallic compound and then pulled up, or a method in which the solution is dropped onto the substrate and the substrate is moved at high speed. A method such as rotating is used. The method of changing the composition in the thickness direction as used in the present invention is as follows:
For example, by preparing a plurality of different solutions of the above-mentioned organic metals and sequentially stacking these layers on a substrate, glass flakes having compositional changes in the thickness direction can be manufactured. At that time, if the next coating is applied before the previously applied solution has not dried sufficiently, the previously applied film may be dissolved by the solution being applied, so be sure to dry thoroughly between each application. need to be done. On the other hand, if drying progresses too much, peeling from the substrate may occur at that point, which is not preferable. Optimal drying conditions are preferably determined experimentally depending on the film forming method used. The thickness of the glass flakes produced by the present invention varies depending on the solution or the conditions during film formation, but is generally between 5 microns and 0.05 microns. If it is thicker than this,
The difference in drying rate between the free surface and the vicinity of the substrate becomes too large, and delamination occurs in the direction horizontal to the substrate. On the other hand, if it is thinner than 0.05 micron, the adhesion between the substrate and the film becomes too great, and the film will not peel off from the substrate and will not form flakes. Regarding sintering, there are no particular limitations on the method. It is desirable that the sintering temperature and time be at or above the conditions that ensure the transition from gel to glass. Depending on the purpose of use, it may not be necessary to perform iM after drying. Examples are shown below. Example Commercially available silicone tetramethoxide 1001 and ethanol 10100O were mixed, and 0.1N hydrochloric acid 501
was gradually added dropwise. This liquid is called liquid A. Next, commercially available titanium isopropoxide 50ml, ethanol 1010ml
0O was mixed. This is called liquid B. A liquid is silica, B
The liquid produces titania. 20cm x 20c, surface polished and smooth
A stainless steel plate with a thickness of 1 mm is immersed in liquid A at m, and pulled up vertically at 20 cm/min to form a thin film.
It was left in the air to dry for 10 minutes. Next, this was immersed in liquid B and pulled out under the same conditions to form a film. After drying at room temperature for 10 minutes, it was immersed in Solution A again to form a film under the same conditions. The three-layer film thus obtained was placed together with the stainless steel substrate in a dryer at 80°C and dried for 1 hour. As a result of this drying, the three layers of the gel film were difficult to peel off from the substrate, and the gel film formed into flakes of about 5 mm x 5 mm. This was further sintered at 800°C for 1 hour to perform vitrification. After sintering, when examined by X-ray diffraction, it did not show any sharp peaks and was found to be in a glassy state. When this was observed with an electron microscope, it was found to be flaky glass with a film thickness of about 0.9 microns. Also, ESCA
According to the compositional analysis in the thickness direction by A, the first layer and the third Fi are each about 0. It was found to be 35 microns of amorphous silica, with the intermediate second layer of Part B being about 0.2 microns of crystalline titania (anatase). The surface of this flake has a lower refractive index (and therefore less gloss) than the intermediate third layer, and a glass flake that absorbs ultraviolet rays is obtained.

【Effect of the invention】

According to the present invention, glass flakes having a compositional change in the thickness direction, which has been difficult to manufacture in the past, can be easily and efficiently manufactured. Patent applicant Nippon Sheet Glass Co., Ltd.

Claims (2)

[Claims] (1) Glass flakes consisting of multiple layers having different glass compositions in the thickness direction. (2) A first solution containing an organometallic compound is applied onto a substrate with a smooth surface, dried, and then a second solution containing an organometallic compound having a composition different from that of the first solution is applied on top of the substrate. 1. A method for producing glass flakes consisting of a plurality of layers having different glass compositions in the thickness direction, the method comprising coating the glass on glass, drying and sintering the glass.