JPH04295023A - Apparatus for producing flaky glass - Google Patents

Abstract

PURPOSE:To stably, easily and efficiently produce flaky glass by applying a soln. contg. an org. metal compd. on the circumferential surface of a rotating cylinder, then drying and peeling the coating. CONSTITUTION:A coating device 2, a drying furnace 3 for the coated film, a capturing device 4 for flakes and a washing device 5 for the drum surface are attached to the circumference of a drum 1 which is made of a stainless steel having about 2mm thickness, has the circumferential surface polished to a mirror surface and has 50 to 500cm diameter and 30 to 300cm width. The drum 1 is driven at 0.5 to 20 revolutions per minute. An alcohol soln. of the org. metal compd. (e.g. metal alkoxide) is so applied on the drum from the coating device (e.g. rod coater) 2 as to attain 0.06 to 50mum thickness of the coated film. The drying furnace 3 is heated for 10 to 5 minutes at 40 to 500 deg.C and a part of the coated film peels simultaneously with the passage of the drum. The capturing device 4 is a suction device installed at about 5mm above the circumferential surface and the captured flakes are heated to about 800 deg.C in another electric furnace, by which the flaky glass of 5 to 0.5 micron thickness is obtd.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION The present invention provides an apparatus that can easily and efficiently produce glass flakes using a solution containing an organometallic compound as a starting material. Incidentally, the term "flake glass" as used in the present invention refers to thin pieces of glass each having a length and a width of about 5 mm or less.

0002

BACKGROUND OF THE INVENTION Glass flakes are currently used in plastic fillers, corrosion-resistant linings and 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 need for thinner glass flakes with compositions that can withstand higher temperatures, but conventional methods have limitations.

[0003] A technique for manufacturing a thin glass plate from a solution containing an organic metal is, for example, as described in Japanese Patent Publication No. 34219/1983 disclosed by Shinbo et al. It is known to make thin glass by floating it on another liquid. According to this published patent, it is said that thin glass pieces of 1 micron or less can be obtained, and it can be inferred that glass flakes can be manufactured by crushing these pieces. Using this technology, it is possible to produce glass flakes, but this technology has drawbacks such as: (1) It is difficult to collect glass pieces floating in water, and (2) It is difficult to obtain a uniform film thickness. Therefore, it is practically difficult to industrially produce glass flakes using this technique.

0004

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, the present invention provides an apparatus that can easily, efficiently, and stably produce glass flakes from a solution containing an organometallic compound. It is something to do.

[0005]

[Means for Solving the Problems] The present invention provides a rotating device having a rotating cylindrical circumferential surface, and means provided along the circumferential surface for applying a solution containing an organometallic compound to the circumferential surface. , an apparatus for producing glass flakes, comprising means for drying the coating film, and means for collecting flakes obtained by peeling off the dried coating film from a circumferential surface.

The rotating device in the manufacturing apparatus of the present invention has a rotating cylindrical circumferential surface. As the base material constituting this cylindrical circumferential surface, materials that can be processed into a cylindrical circumferential surface (drum shape) and have strength are used, such as stainless steel,
Metals such as aluminum and plastics such as vinyl chloride and polyethylene are preferred. Use materials with smooth surfaces. Further, these materials may be coated with another material, for example by plating. By rotating the cylindrical circumferential surface around its central axis and feeding the cylindrical circumferential surface at a constant speed, a solution containing an organometallic compound is evenly applied to the surface, resulting in flakes with highly uniform thickness. glass can be produced.

The size and rotation speed of the cylindrical circumferential surface are as follows:
There are no particular restrictions, and it is determined based on the required production volume. Approximately 50 to 500 cm in diameter due to ease of mechanical processing etc.
m, width 30-300 cm, preferably operating at 0.5-20 revolutions per minute. A drum larger than this is not a good idea as it takes a lot of effort to rotate it. The organometallic compound used to produce glass flakes using the production apparatus of the present invention may basically be any compound as long as it undergoes hydrolysis and dehydration condensation, but metal alkoxides having an alkoxyl group are preferable. More specifically, methoxide, ethoxide, etc. of silicon, titanium, aluminum, zirconium, phosphorus, boron, etc.
Propoxide, butoxide, etc. are used alone or as a mixture. Therefore, the composition of the flaky glass obtained by the present invention is, for example, pure silica, silicate-based, titanate-based, aluminate-based, zirconate-based,
It is a phosphate-based or borate-based amorphous or crystalline substance.

[0008] The solvent for the solution containing the organometallic compound is
Basically, any solvent may be used as long as it dissolves the above-mentioned organometallic compound, but alcohols such as methanol, ethanol, propanol, and butanol are most preferred. The amount of this solvent used is 0.1 to 0.995, preferably 0.2 to 0.9, in volume ratio to the total amount of organometallic compound and solvent.
More preferably, it is 0.2 to 0.85.

[0009] Moisture is necessary for the hydrolysis of the organometallic compound. This water may be neutral, 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. The amount used is preferably in the range of 1 mol to 100 mol of water per 1 mol of the organometallic compound. The amount of acid used is 0.01 to 2, preferably 0.05 to 2, in molar ratio to the organometallic compound.
It is 1.5. 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, it may remain as a carbide on the thin film due to heating in the final stage, so it should be kept at 10% by weight or less.

In the present invention, the means for applying a solution containing an organometallic compound to a circumferential surface is provided along the circumferential surface of the rotating device. Examples of this method include coating a part of the circumferential surface by immersing it in a solution bath contained in a bathtub, a doctor blade method, a rod coating method, or a spray coating method, which can form a thin film on the circumferential surface. The means are illustrated. By this coating means, the liquid containing the organometallic compound is applied to the substrate to form a thin liquid film of 0.06 to 50 μm.

Next, means for drying the coating film, such as heating means, is provided along the circumferential surface of the rotating device. Here, the coated film and substrate are dried, and the solvent is mainly evaporated. The film attached to the circumferential substrate contracts here and peels off. The heating means for promoting evaporation has a temperature range of approximately 40°C to 500°C and a heating time of approximately 10°C.
Designed to last from seconds to five minutes. Even if the drying process is carried out further than this, there is no essential improvement and the heat source is only wasted. Next, a means for collecting the flakes obtained by peeling off the dried coating film from the circumferential surface, for example, a means for collecting the flakes by reducing the pressure and suctioning the atmosphere around the coating film, is installed along the circumferential surface. It is provided.

[0012] In the present invention, the above-mentioned three means, a coating means,
In addition to using the drying means and the collecting means, there is no problem in combining various means. For example, means for cleaning the substrate and means for drying the substrate can be provided after the means for collecting flakes. In other words, both of these means completely remove the remaining flakes and other contaminants from the substrate after the collection of flakes is completed, and make the substrate ready to be coated with the solution again. Preferable from the viewpoint of quality control. The cleaning means may be any commonly used cleaning means, although it depends on the type of substrate. Mechanical cleaning with a brush using a commercially available detergent is simple and effective.

[0013] The thickness of the glass flakes produced by the present invention varies depending on the solution or the conditions during film formation, but
It 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, resulting in interlayer peeling in a 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, sintering after drying may not be necessary.

Examples are shown below.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an apparatus for producing glass flakes according to the present invention. This manufacturing equipment is made of a stainless steel plate with a thickness of 2 mm and a mirror-polished circumferential surface, and the diameter of the drum is 100 cm.
around a drum 1 with a width of 50 cm, a device 2 for applying a solution containing an organometallic compound, a drying oven 3 for drying the coating film, a device 4 for collecting exfoliated flakes, and a drum surface It consists of a device 5 for cleaning. The drum 1 is driven to rotate around its central axis 10. The device 2 for applying this solution is a device called a rod coater, and the lower part of a stainless steel rod with a diameter of 6 mm is immersed in the melt tank 6, and the upper part is the drum. is in contact with. The solution-coated surface of the bar emerging from the solution bath contacts the drum surface, coating the surface with the solution. Commercially available silicone tetramethoxide 1000ml, ethanol 1000ml,
A portion of a solution mixed with 1200 ml of 0.1N hydrochloric acid was prepared in the bathtub 6.

[0015] The above stainless steel drum was rotated once per minute to produce flakes. Drying was carried out by maintaining an electric furnace 3 having an electric resistance heating element inside at 80°C.
As the drum passes, part of the coating peels off. The flakes are collected by a suction device installed approximately 5 mm above the circumferential surface of the drum. The flakes collected here were heated to 800° C. in another electric furnace to form glass flakes. The drum cleaning and drying device 5 includes a brush 7 and a dryer 9 that rotate in the opposite direction to the direction in which the substrate travels. Here, in order to enhance the cleaning effect, a device 8 for spraying pure water is installed in front of the brush 7. The substrate is dried in a hot air dryer 9. Note that this embodiment is only one example of the present invention, and the present invention is not necessarily limited to this example.

[0016]

According to the present invention, thin glass flakes, which have been difficult to produce in the past, can be produced continuously, simply and efficiently.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

1. ．． Drum surface of rotating device 2. ．． Apparatus for applying the solution3. ．． Drying oven for drying the coating film 4. ．． Device to collect flakes

Claims (1)

[Claims] 1. A rotating device having a circumferential surface of a rotating cylinder, means provided along the circumferential surface for applying a solution containing an organometallic compound to the circumferential surface, and drying the coating film. and a means for collecting flakes obtained by peeling off the dried coating film from a circumferential surface.