JPS62162650A - Production of inorganic plate with reduced surface reflection - Google Patents

Abstract

PURPOSE:A specific solution for forming clear coating films is atomized and the particles remaining after removal of large-size particles from the atomized product are coated on the substrate whereby inorganic plates with reduced surface reflection are readily and efficiently produced. CONSTITUTION:An organosilicon-containing solution for forming clear coatings in tank 16 such as a solution of a metal alcoholate, e.g., ethyl silicate of the formula, in an alcohol, is atomized from the spray 14 through the pipe for feeding the atomization air 15 and bed into the pipe 17. The resultant mist is transferred along with the air flow and particles of larger diameters are removed by means of wall surface on the turning corner 21. The remaining fine particles are sent through pipe 21 into coating chambers 9. Then, the agitation blades 23 in the room 9 is allowed to rotate, the mist particles are allowed to fall down on the substrate 8 such as quartz glass whereby clear inorganic coating layer is formed on the substrate. Then, the product is dried by heating at 100-130 deg.C for 10-60min to form clear inorganic coating films with fine roughness of 0.1-2mum height on the inorganic substrate.

Description

[Detailed Description of the Invention] [Field of Application in Industry] The present invention relates to a method for manufacturing an inorganic board with reduced surface reflection, and more specifically, an inorganic board having a large number of fine ridges on the surface thereof. The present invention relates to a method of manufacturing an inorganic plate provided with a transparent inorganic coating and with reduced surface reflection.

[Technical background of the invention and its problems] Glass plates for the surface of color TV cathode ray tubes and display parts of electronic devices 1 Inorganic plates used as watch face plates, glass plates for show windows, etc. If light rays are reflected, it becomes difficult to see images or internal objects, so it is desired to prevent reflection of external light rays on the surface of the inorganic plate.

Conventionally, the reflection of external light on the surface of an inorganic plate has been prevented.

This was achieved by applying, for example, hydrofluoric acid to the surface of an inorganic plate to form a large number of fine irregularities on the surface. However, this method uses hydrofluoric acid, which is an extremely strong acid, which is dangerous to handle, and also requires treatment when disposing of used hydrofluoric acid. there were.

Therefore, it has been desired to develop a method that can provide a large number of fine irregularities on the surface of an inorganic plate without using strong acids such as hydrofluoric acid.

As one method for solving such problems, a method has been proposed in which a fluororesin or the like is coated on the surface of an inorganic plate as a coating with a low refractive index. According to this method, it is easy to apply a large-sized inorganic plate to the surface of the inorganic plate, but it has poor heat resistance, so it is not suitable for manufacturing inorganic plates that require a heat treatment process, such as for color TV cathode ray tubes or display tubes. The problem was that it could not be applied.

[Purpose of the Invention] The present invention aims to solve the problems associated with the prior art as described above, and aims to uniformly form a large number of fine irregularities on the surface of an inorganic base material without using hydrofluoric acid. The object of the present invention is to provide a method for manufacturing an inorganic plate with reduced surface reflection.

[Summary of the Invention] The method for manufacturing an inorganic plate with reduced surface reflection according to the present invention involves spraying and atomizing a solution for forming a transparent film containing each organosilicon compound, and transporting the resulting atomized material with an air flow. After removing the atomized material with large particle size, the atomized material is applied onto the substrate to form a transparent inorganic coating, and the resulting coating is then heated to dry and bake. It is characterized by doing the following.

According to the method for manufacturing an inorganic board according to the present invention as described above,
A transparent inorganic coating having many fine ridges having a height of 0.1 to 2.01 bm uniformly can be formed on the inorganic base layer, thereby reducing surface reflection. Moreover, even if the inorganic substrate is planted over a large area, a uniform transparent inorganic coating can be easily formed.

[Detailed Description of the Invention] Inorganic substrates used in the present invention include silicate glass (quartz glass), alkali silicate glass, soda lime glass, potash lime glass, lead glass, barium glass, borosilicate glass, etc. Silicate glasses are primarily used, but are not limited to these, such as phosphate glasses, borate glasses, sulfate glasses, nitrate glasses, carbonate glasses, chloride glasses, fluoride glasses, etc. Glass can also be used.

Any other thermally stable base material can be used as the base material in the present invention.

In addition, when using the inorganic plate obtained by the present invention as a display cathode ray tube or a clock face plate,
It is preferable to use a transparent material as the inorganic base material.

To form a transparent inorganic coating on such an inorganic base layer,
A solution containing an organosilicon compound is used as a solution for forming a transparent inorganic film.

As a solution for forming a transparent inorganic film containing an organosilicon compound, ethyl silicate [S r (C2Hs O)
An ethyl silicate alcohol solution prepared by dissolving a metal alcoholade such as a ] in an alcohol solution is mainly used. In addition, in order to adjust the thermal expansion coefficient or firing temperature of the resulting coating, butylborate tB (
canso)3] -methy/l/bora-)[B(OCH
3) 31, sodium ethylate [Naoc2H5],
Sodium methylate [Na0CH31, lithium ethylate [LiOC2H5], aluminum propoxide [AI(QC3H)],! J7 acid t'): r-fkx
An alcohol solution such as f-rad [PO(0(1,,H5)) may be added to the ethylsilicate alcohol solution.

Further, for the purpose of adjusting the viscosity of the film-forming solution, an alcohol such as methanol, ethanol, propatool, butanol, etc. is used in combination with the above-mentioned alcohol solution.

The type of alcohol used influences the rate of hydrolysis of the metal alcoholade.

For example, when using methanol or ethanol, the rate of hydrolysis of the metal alcoholade is greater than when using propatool or butanol.
Therefore, it is preferable to select the alcohol to be used in consideration of the hydrolysis rate of the metal alcoholade.

As the hydrolysis regulator, inorganic acids such as hydrochloric acid and nitric acid, or organic acids such as acetic acid can be used, and among these, hydrochloric acid is particularly preferred.

For example, in the case of 12N hydrochloric acid, the hydrolysis regulator is
0.5 to 2 o per 100 g of film forming solution
It is preferable to add the acid in an amount such that the acidity is 10 to 20 ppm. When using an acid as a hydrolysis regulator, if the amount of acid added is too small, the rate of hydrolysis of the metal alcoholade will be slow. If the amount of acid added is too large, the hydrolysis rate of the metal alcoholade will be too fast, gelation will proceed too much, and the viscosity of the film-forming solution will increase, making it difficult to apply.

A solution for forming a transparent inorganic film containing the above-mentioned components is hydrolyzed by moisture present in the air and becomes a gel.

Therefore, this hydrolysis progresses more easily as the humidity becomes higher and the temperature becomes higher, and furthermore, it becomes easier to progress as the film-forming solution is stirred.

Specifically, while considering the above conditions, the room temperature is 15 to 25
℃ and relative humidity of 30 to 60%, while stirring the film forming solution at about 200 to 800 revolutions per minute, it is preferable to allow the hydrolysis reaction of the metal alcoholade to proceed gradually over time.

When the hydrolysis reaction of the metal alcoholade is allowed to proceed while stirring the film-forming solution in this way, the solution gels and the gel phase is destroyed by the stirring, forming a fine gel phase and a gel phase. becomes a confused state. In this state, if gelation is insufficient and the content of the gel phase is low, there will be fewer fine ridges that will later be formed on the inorganic base layer, and the height will also be lower, which is undesirable. If the coating progresses too much, the viscosity of the film-forming solution will increase excessively, making the coating operation difficult, which is not preferable.

Next, the film-forming solution obtained as described above is applied onto the inorganic base layer to form a film.

When applying a film-forming solution containing an organosilicon compound onto an inorganic substrate, in the present invention, the solution is first sprayed and atomized by a spray method or the like. At this time, it is preferable to select conditions such that the obtained atomized material has a particle size as fine as possible.

The atomized film-forming solution thus sprayed and atomized is transported along with the air flow, and the atomized materials with large particle sizes are removed. At this time, if the humidity of the air flow is too high, the hydrolysis of the organosilicon compound will be promoted too much, which is undesirable. Therefore, it is preferable to use a dry air flow.

When the above-mentioned atomized film-forming solution is transported in an air stream, the large particles of the M-shaped particles fall in a parabolic trajectory.

At this time, if the air flow path is made curved instead of straight, or if the flow path is provided with a bend, relatively large-diameter atomized materials that are carried along with the air flow will be able to pass through the flow path. When the air flow changes, it is no longer able to be carried along with the airflow, and it collides with the wall and is removed. Therefore, when transporting letters by airflow, it is preferable to provide a curved or bent part in the airflow to make the particle size of the atomized material uniform, rather than keeping the direction of travel of the airflow in a straight line. In particular, by providing a plurality of bends that are sharply bent at a right angle or more in the air flow path, the particle size of the atomized material can be made more uniform. In addition,
The bends in the air y&flow may be horizontal, vertical, or oblique.

The particle size of the atomized material transported also changes depending on the flow rate of the air flow that transports the atomized material; if the flow velocity is fast, large particles will be carried, and if the flow velocity is slow, only small particles will be carried. carried.

Therefore, it is preferable to consider the flow rate of the air flow when transporting the atomized material.

In the mist that collides with the wall and is removed by the air flow, the alcohol evaporates and solidifies, and the mist is piled on top of it to form a pumice stone. Once dissolved, it can be used again as a film-forming solution.

The atomized material from which large particles have been removed in this way is applied onto the substrate so that it falls on the substrate, thereby forming a transparent inorganic coating.

Specifically, a mist of the film-forming solution is introduced into the coating chamber,
It may be applied by pouring a mist onto the base material provided in the room.

At this time, keep the coating room as closed as possible.

It is desirable to fill the room with mist so that it falls evenly on the substrate. Therefore, the door must be opened when the substrate enters and exits the chamber, but the mist does not fall when the substrate is placed inside the chamber. The door should be closed when applying the product onto the substrate.

The inlet of the fog into the room should be located at the top if possible, and the outlet should be located below the base material.

If left as is, a streamline will inevitably flow from the inlet to the outlet,
Since it is difficult to obtain complete uniformity, it is preferable to install a stirring blade above the center of the substrate and gently rotate it at about 2 to 20 RPM so that the mist is uniformly deposited on the substrate.

In this case, although the structure of the apparatus becomes complicated, rotating the substrate is also effective in uniformly applying the coating.

In this way, a mist of the film-forming solution is applied onto the substrate, and it is preferable to perform this application multiple times in order to prevent unevenness from occurring in the formed film. It is also preferable for this reason.

When the organosilicon solution has a large particle size and is sprayed in large quantities at one time, the particles bond together on the substrate, uniformly wetting the surface, forming a smooth coating, and creating fine ridges to reduce reflection. Does not occur.

Therefore, in order to form good fine ridges, the fine particles are attached to the porcelain so as not to cause bonding of the particles, and the viscosity is increased as the alcohol evaporates.

By repeating the process of distributing fine grains again, this can be achieved by piling up grains on top of grains.

For this reason, it is preferable to perform multiple coatings, but of course, in order to minimize "unevenness", it is also preferable to change the direction of the coating inlet/outlet and the positional relationship of the substrate each time.

Next, the applied film is heated to dry and fire the film. The drying process and firing process are as follows:
This may be carried out as a series of steps or may be carried out as separate steps.

The drying process of the film is preferably 100 to 130°C.
The coating film may be heated for about 10 to 50 minutes at 280 to 370°C for 10 to 60 minutes.
The applied film may be heated for about a minute.

Although controlling the heating temperature in the drying process is not very important, controlling the heating temperature in the firing process is important.

However, this temperature range depends on the conditions of the firing furnace, the size of the inorganic large particles, etc., but the purpose can generally be achieved within the above range.

In this way, a height of 0.1 to 2.0 g is deposited on the inorganic substrate.
A transparent inorganic coating having a large number of uniformly fine protuberances is formed, thereby obtaining an inorganic plate according to the present invention.

In addition, in the inorganic plate according to the present invention, the transparent inorganic coating has a thickness of 0.1 to 2. It has a protuberance with a height of OpLm, but since this protuberance has an amorphous amoeboid shape, it varies over a wide range.

Note that in this specification, an inorganic plate does not necessarily mean a plate-like one, but may have a bent shape, and in some cases, an article in which the plate grains have a single curved surface shape. may be formed.

In the above manner, fine ridges are formed on the surfaces of color TV cathode ray tubes, display surface panels of electronic devices, watch surface panels, show window glass panels, etc., which have the effect of reducing surface reflection and making viewing easier. transparent p
1. The machine coating can be easily formed on large-scale transplants with a high healing rate by the spray method.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

[Example] A method for manufacturing an inorganic plate according to the present invention was carried out using the apparatus shown in the drawings. Note that this device is for applying a transparent inorganic film onto a substrate, and subsequent drying and baking were performed using a conventional device.

FIG. 1 is a schematic plan view of the apparatus, in which five coating units are installed at equal intervals so that coating is performed five times.

FIG. 2 schematically shows a vertical section through one of the units.

The conveyor 1 intermittently conveys the base material 8 via a motor 3 and rollers 4 according to instructions from a controller 2 .

When the base material 8 is placed at a predetermined upstream position 5 on the conveyor l, that is, a predetermined position 15 having a distance equal to the intermediate distance between the painting rooms 9, the front and rear doors of the most upstream painting room 9 are opened. 6
, B' opens, and the stopped conveyor 1 moves to the predetermined position 5.
After transporting the base material 8 from the center to the central position 7 of the painting room 3, the front and rear doors B are opened.

6' is closed.

The front and rear 338.8' are opened and closed by the wire 10 and the sill 11 according to instructions from the controller 2.

When the first coating is completed, the doors 8, 6' are opened and closed again and the conveyor is moved, and the base material 8 is moved from the central position Wi7 of the painting room 9 to the intermediate position 1a12 between the next painting room 3. The new base material 8 carried and supplied to the predetermined position 5 is carried to the central position 7 of the coating room 9 in the same manner as described above.

In this way, by moving the conveyor intermittently, the coating is repeated.

When tested on a 6-inch color television cathode ray tube face plate, it was appropriate to complete one conveyor move in 10 to 30 seconds and to apply one application in 20 to 50 seconds.

After coating five times, when the base material 8 comes out at a predetermined position 13 downstream of the conveyor 1, it is moved to the drying and baking process.
The drying and firing steps were performed in a commonly used tunnel electric furnace.

The application unit was atomized using Spray 14.

Spray 14 was sprayed continuously because it was undesirable to spray it intermittently as it would cause coarse particles and dripping from the nozzle.

15 is an air supply pipe for spraying, and 1B is an organosilicon solution tank.

The organosilicon aqueous solution is suctioned by the pressure of the atomizing air and reaches the spray 14, where it is atomized from the tip and blown into the conduit 17. The conduit is provided with a plurality of bends 18.

The coarse particles in the mist are removed by colliding with the wall surface at the bend 18 of the airflow, and only the fine particles that can be entrained in the airflow are carried to the painting room 3.

If the speed of the air flow is fast, relatively large particles will be carried, and if the air flow is slow, particles of relatively small size will be carried.

The speed of the air flow is adjusted by the amount of air from the blowing air supply pipe 19.

That is, as the amount of blowing air increases, the speed of the air flow increases.

The coarse particles that collide with the wall flow down the wall and are accompanied by vaporization of the solvent, increasing the viscosity and partially solidifying. They are taken out from the discharge port 20 at any time, collected, and reused.

The air flow containing fine atomized particles passing through the plurality of bends 18 enters the coating chamber 9 via a conduit 21.

A stirring blade 2 driven by a motor 22 is mounted on the ceiling of the painting room 9.
3 is provided.

The stirring χ23 is rotated at a gentle speed of 10 to 30 RPM, so that the mist from the conduit 21 uniformly fills the coating chamber θ.

The filled mist quietly descends inside the coating chamber a and is applied onto the substrate 8, and the remainder passes through the conduit 22 from the lower part of the coating chamber 3 and is exhausted through the exhaust pipe 23.
In the exhaust stack 23, the mist is mixed with the outside air, so it is hydrolyzed, increases its viscosity, and is collected.

Apply 5 times using Q equipment, dry at 100-130°C for 10-50 minutes, and dry at 280-370°C for 10-50 minutes.
By performing baking for 80 minutes, a transparent inorganic coating could be formed on the substrate.

The transparent inorganic coating thus formed has a height of 0 on the surface.
．． 1 to 2.0 JL Peng, it has an amorphous amoeba-like protuberance with a diameter of about 1 to 10 liters, and has the effect of making the image of a fluorescent light appear hazy and indistinct. have.

That is, since this film is made of silicic acid and has a refractive index lower than that of the base material, and also has a finely uneven surface, it has the effect of significantly reducing surface reflection.

The following materials were used as the base material and the solution for forming the transparent 11 inorganic film.

5■ S, 02: 83% AIO: 2% RO: 19% RO: 1B% (RO is an alkaline earth metal oxide such as CaO, SrO, BaO, PbO, etc., and RO is 20, Na2
Alkali metal oxides such as O and L120. ) In addition to the above, this base material also contains trace amounts of Neo and Ga2O.
.

Contains coloring metal oxides such as Cr2O3.

This base material is available as a glass plate for color cathode ray tubes.

The coefficient of thermal expansion of this base material is HX 10-7/''O,
The softening point is 630°C and the annealing point is 500°C.

+1 Ethyl silicate 5% by weight Ethanol 35% by weight Improper tool 20% by weight Butanol 40% by weight 0.9 mg of 12% hydrochloric acid was added to the obtained solution 1 onH to prepare a transparent inorganic film forming solution.

This solution was stirred with a stirrer at a speed of 400 revolutions per minute for about 3 hours in a room at a temperature of 18° C. and a relative humidity of 35%.

[Effects of the Invention] According to the present invention, it is possible to easily and efficiently form, even over a large area, a transparent inorganic coating having a large number of uniformly fine ridges capable of reducing surface reflection on an inorganic plate. .

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of an apparatus used to carry out the method of manufacturing an inorganic plate with reduced surface reflection according to the present invention. 8... Base material 9... Painting chamber 14Φ... Spray 18... Bent part 23... Stirring blade

Claims (2)

[Claims] (1) A solution for forming a transparent film containing an organosilicon compound is sprayed and atomized, and the resulting atomized material is transported along with an air flow to remove the atomized material with a large particle size, and then the atomized material is transferred to the substrate. A method for manufacturing an inorganic plate with reduced surface reflection, characterized by forming a transparent inorganic film on a base material by applying the film in a downward motion, and then heating the obtained film to dry and bake it. . (2) When transferring the obtained mist with the air flow,
The method of manufacturing an inorganic plate with reduced surface reflection according to claim 1, characterized in that a bent portion is provided in the air flow.