JPH05246732A - Device for producing flaky glass - Google Patents

Abstract

PURPOSE:To improve production efficiency by dropping a soln. contg. an organometallic compd. from a slit by gravity, passing a substrate below the slit to coat the substrate with the soln., drying the obtained coating film, releasing the film from the substrate and collecting the obtained flakes. CONSTITUTION:An organometallic compd. such as silicon tetramethoxide is dissolved in a solvent such as ethanol, and aq. hydrochloric acid is added to prepare a coating soln. The soln. is supplied to a bath from a coating soln. tank 6 through a pump 7 so that the height of the soln. is fixed in the bath. The soln. is dropped from a slit and applied on a belt-shaped substrate 1, and the excess soln. is recovered by a soln. receiver 8 set below the substrate 1 and returned to the tank 6. The substrate is then passed through an electric furnace 3 kept at 40-500 deg.C, and the obtained coating film is released and flaked. The flakes are collected by a sucker 4 furnished with a rotary brush 9 and heated to a specified temp. to obtain a flaky glass. The substrate 1 is washed and then dried by a hot-air drier 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an apparatus capable of easily and efficiently producing flaky glass in the production of flaky glass using a solution containing an organometallic compound as a starting material. The flake-shaped glass referred to in the present invention refers to glass flakes each having a length and width of about 5 mm or less.

Flake glass is currently used in plastic fillers, corrosion resistant linings and paints. Such flake-like glass is mostly soda-lime silicate glass-based compositionally, and has a thickness of about 4 microns. Inflate the molten glass like a balloon,
It is manufactured by quenching and crushing. With the development of industry, thinner flaky glass having a composition capable of withstanding higher temperatures is required, but there is a limit in the conventional method.

A technique for producing a thin glass plate from a solution containing an organic metal is described in, for example, Japanese Patent Laid-Open No. 51-34219 disclosed by Shinbo et al., Which is a solution after hydrolysis and dehydration condensation. There is known a method of forming a thin glass by floating the above on another liquid.
According to this publication, thin glass pieces of 1 micron or less are obtained, and it can be inferred that flake-shaped glass can be produced by crushing this. Although there is a possibility that flaky glass can be produced by using this technique, this technique has drawbacks such as difficulty in recovering glass pieces floated on water and difficulty in obtaining a uniform film thickness. Therefore, it is practically difficult to industrially produce glass flakes with this technique.

The present inventors have previously applied a solution containing an organometallic compound to a base material having a smooth surface, dried it, peeled it from the base material, and sintered it to obtain a very large amount. We have found that thin glass flakes can be manufactured easily and efficiently. As its manufacturing apparatus, a means for applying a solution containing an organometallic compound to a loop substrate, a means for drying the coating film, and a means for collecting flakes obtained by peeling the dried coating film from the loop substrate. And a loop-shaped substrate, and a flake-shaped glass manufacturing device in which a loop-shaped substrate forms a circulating conveyance path that sequentially and sequentially passes through a coating means, a drying means, and a collecting means, and a patent application was filed. .. (Japanese Patent Application No. 2-152355) At that time, a dipping method was illustrated as an example of a coating method that can be recommended.

In the above manufacturing apparatus by the present inventors, for example, in the dipping method,
When coating a wide area, there is a problem that the bath for immersing the substrate becomes large, and the coating speed cannot be increased because the film thickness increases as the coating speed increases.

In view of the above problems, the present invention provides a coating apparatus for efficiently and rapidly coating the manufacturing apparatus by the present inventors.

Means for Solving the Problems The present invention comprises means for spontaneously dropping a solution containing an organometallic compound from a slit to apply it to a substrate, means for drying a coating film of the solution containing the organometallic compound, and after drying. The apparatus for producing flaky glass having means for collecting flakes obtained by peeling the coating film from the substrate.

In the coating apparatus of the present invention, the coating solution is stored in a bath, a fixed amount of the solution flows out in a flat plate shape from a slit attached to the lower portion of the bath, and the flowing out coating solution is continuously applied to the substrate. It is applied. The length of the slit is preferably slightly longer than the substrate to be coated. The width of the slit is defined by the slit length, the viscosity of the coating solution, the coating amount, and the like. However, if the width is narrow, inconveniences such as clogging by foreign matter and the coating amount becoming too small occur.
If it is too wide, liquid shortage and unevenness are likely to occur. 0.05 to 5 mm is suitable. It is necessary to keep a constant amount of coating liquid in the bath with a pump.

Since the coating solution only flows out through the slit, a large bath for dipping the substrate is not required as in dipping. Also, since the amount of the coating solution can be regulated by adjusting the pressure (solution head), the coating amount can be set according to the speed of the substrate, and high-speed coating is possible.

The substrate is preferably a metal such as stainless steel or aluminum, or a plastic such as vinyl chloride or polyethylene. In each case, the surface is smooth. Further, these materials may be coated with another material, for example, by plating. From the viewpoint of continuous production, it is efficient to use an endless substrate such as a belt.

The organometallic compound used for producing the glass flake using the production apparatus of the present invention is hydrolyzed,
Basically, any compound may be used as long as it can be dehydrated and condensed, but a metal alkoxide having an alkoxyl group is preferable. More specifically, methoxides such as silicon, titanium, aluminum, zirconium, phosphorus, and boron, ethoxides, propoxides, butoxides, etc. are used alone or as a mixture. Therefore, the composition of the glass flake obtained by the present invention is, for example, pure silica, silicate-based, titanate-based, aluminate-based, zirconate-based, phosphate-based, borate-based amorphous. Or it is crystalline.

The solvent of the solution containing the above organometallic compound is
Essentially any organic solvent can be used as long as it can dissolve the 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 0.95, and more preferably 0.2 to 0.85 in volume ratio with respect to the total amount of the organometallic compound and the solvent. is there.

Moisture is necessary for the hydrolysis of the organometallic compound. This may be neutral, acidic or basic, but in order to accelerate hydrolysis, it is preferable to use water acidified 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 with respect to 1 mol of the organometallic compound. The acid is used in a molar ratio of 0.01 to 2, preferably 0.05, with respect to the organometallic compound.
~ 1.5.

In addition, an organic thickener or the like may be added to change the characteristics of the liquid. However, if this addition amount is large, it may remain as a carbide on the thin film due to the heating in the final stage, so it should be kept at 10% by weight or less. The thickness of the applied film is usually 0.1 to 10 μm.

Next, means for drying the coating film, for example, heating means, is provided along the coating surface of the substrate. Here, the coated film and substrate are dried to evaporate mainly the solvent. The film adhered to the coated surface of the substrate contracts and peels off here. The heating means for promoting evaporation is designed so that the temperature range is approximately 40 ° C. to 500 ° C. and the heating time is approximately 10 seconds to 5 minutes. Further drying will not result in any substantial improvement and will simply waste heat. Next, means for collecting flakes obtained by peeling the dried coating film from the coating surface, for example, means for depressurizing and sucking the atmosphere around the coating film to collect the flakes are provided along the coating surface. ing.

In the present invention, the coating means which is the above three means,
Other than using the drying means and the collecting means, there is no problem even if various means are combined. For example, the substrate cleaning means and the substrate drying means can be provided after the means for collecting the flakes. That is, both these means are means for completely removing the flakes remaining from the substrate and removing other stains at the stage when the collection of the flakes is completed, so that the solution can be applied to the substrate again. It is preferable in terms of quality control. The cleaning unit may be a commonly used cleaning unit, although it depends on the type of the substrate. It is simple and effective to use a commercially available detergent and mechanically clean it with a brush.

The thickness of the glass flake produced by the present invention varies depending on the solution or the conditions during film formation.
It is generally between 5 and 0.05 microns. If it is thicker than this, the difference in the drying speed between the free surface and the vicinity of the substrate becomes too large, and the film peeling in the horizontal direction occurs on the substrate. On the other hand, if the thickness is less than 0.05 μm, the adhesion between the substrate and the film becomes too large, and the film does not peel off from the substrate, and does not form flakes.

There is no particular limitation on the method for sintering. It is desirable that the sintering temperature and time be heated above the conditions that ensure the gel-to-glass transition.
Depending on the purpose of use, sintering after drying may not be necessary.

Examples will be shown below.

EXAMPLE FIG. 1 shows a flake-shaped glass manufacturing apparatus of the present invention. The present manufacturing apparatus includes a belt-shaped substrate 1, a slit-applied apparatus 2 installed around the belt for naturally dropping and applying a solution containing an organometallic compound, a drying oven 3 for drying a coating film, It is composed of a device 4 for collecting the flaked flakes.

The belt-shaped substrate 1 is a mirror-polished stainless belt having a thickness of 0.5 mm, a width of 30 cm, and a length of 20 m. The belt-shaped substrate has a diameter of 100 cm,
It is driven by a drum 5 having a width of 50 cm.

The coating device 2 for coating this solution is
The bath is a bath having a slit with a width of 2 mm and a length of 30 cm attached to the bottom, and the coating solution is supplied from a coating solution tank 6 using a pump 7 so that the height of the solution in the bath is always constant. The solution dropped from the slit is applied to the belt-shaped substrate 1, and the excess solution is collected by the solution receiver 8 provided below the belt-shaped substrate 1 and returned to the coating solution tank 6 again.

The drying was carried out by keeping the electric furnace 3 having an electric resistance heater inside at 120 ° C. However, at the same time when the belt passed, the coating film was peeled off to form flakes.

The flakes are collected by a suction device installed about 5 mm above the surface of the belt-shaped substrate. In order to ensure recovery, the rotating brush 9 is installed in the suction port so as to contact the belt. The flakes collected here were heated to 800 ° C. in another electric furnace to form flaky glass.

The cleaning of the belt-like substrate is performed by a device 10 for spraying pure water and a brush 11 which rotates in the direction opposite to the traveling direction of the substrate.
Done in. The substrate is dried by the hot air dryer 12.

As the coating solution, a commercially available silicon tetramethoxide, ethanol, and 0.1N hydrochloric acid mixed in a volume ratio of 1: 1: 1.2 are used. Was produced at a speed of 5 m / min to produce flakes.

In this method, it is not necessary to use a large bath, so that a compact device is possible. Further, even if the belt speed was increased to 5 m / min, flakes having an average thickness of 0.5 μm and a standard deviation of 0.5 μm and having a very uniform film thickness could be continuously obtained.

This embodiment is only an example of the present invention and is not necessarily limited to this example.

According to the present invention, thin flake-shaped glass, which has been difficult to manufacture in the past, can be manufactured continuously, at a relatively high speed, and easily and efficiently without using a huge apparatus. .

[Brief description of drawings]

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

[Explanation of symbols]

 1-Continuous belt-shaped substrate to be coated 2-Apparatus for applying solution 3-Drying oven for drying coating film 4-Device for collecting flakes 5-Drum for driving belt-like substrate 6-Coating solution tank 7 ・ Pump 8 ・ Solution receiver 9 ・ Brush for collecting flakes 10 ・ Pure spraying device for cleaning belt-shaped substrates 11 ・ Brush for cleaning belt-shaped substrates 12 ・ Drying oven for drying belt-shaped substrates

Claims (1)

[Claims] 1. A means for spontaneously dropping a solution containing an organometallic compound from a slit and passing the substrate under the dropping solution to apply the solution onto the substrate, and a means for drying a coating film of the solution. An apparatus for producing flaky glass, comprising means for collecting flakes obtained by peeling the dried coating film from a substrate.