JP2000096237A - Production of electromagnetic wave shielding glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance practical performance such as adhesion and long-term durability at a low cost by blowing a volatile or sublimable metal compound and, optionally, a metal compound for doping on a glass substrate and bringing them into reaction to form a thin electrically conductive metal oxide film. SOLUTION: One or more volatile or sublimable metal compounds that react with oxygen or moisture in the air or with a compound allowed to exist in the air to form metal oxides and, optionally, a compound of a metal to be doped into the metal oxides are blown in a gaseous state at a prescribed temperature together with a carrier gas such as N2 on a glass substrate kept at a prescribed temperature and they are brought into chemical reaction. The metals of the metal oxides are preferably selected from the groups IIB, IIIA, IIIB, IV A and IVB metals. A thin electrically conductive metal oxide film having <=103 Ω/sq. surface resistance, >=50% entire light transmittance and high adhesion is formed at a high rate and the objective electromagnetic wave shielding glass excellent in practical performance is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an electromagnetic shielding glass.

[0002]

2. Description of the Related Art In recent years, electromagnetic interference has become a problem.
For example, electronic devices are entering offices and ordinary homes due to the development of a highly information-oriented society and the advent of a multimedia society. However, the number of cases where malfunctions of these electronic devices are caused by electromagnetic waves entering from outside is increasing. is there.
In addition, it is also possible to eavesdrop on information and confidential matters of information of companies and individuals of electronic devices by receiving radio waves of the electronic devices. Furthermore, there is a concern that electromagnetic waves generated from high-voltage power transmission lines may cause health problems for the residents there.At medical sites, electromagnetic waves generated by mobile phones and laser scalpels may cause cardiac pacemakers. There is also a concern that it may cause a malfunction such as stopping. To prevent these electromagnetic interference,
The demand for shielding electromagnetic waves in offices and homes is increasing. When shielding a building or general house from electromagnetic waves, the entire building or house must be shielded. The reason is that a small leak does not function because there is an ingress and egress of electromagnetic waves from there. When the entire surface is shielded from electromagnetic waves, roofing materials, flooring materials, wall materials, and the like are relatively easy. This is possible by embedding a conductive material such as a wire mesh in these materials.
However, residential and office spaces require a window material as a lighting part. It is difficult to shield a transparent window glass from electromagnetic waves while maintaining transparency. At present, as a method of shielding electromagnetic waves of glass, for example,
A PVD (physical deposition) method such as forming a silver thin film which is a conductive thin film by a sputtering method or the like is employed.
However, this general method is used for forming a thin film.
Ancillary equipment such as a vacuum device is required, and not only large investment is required, but also the productivity of the thin film is low due to a low film formation speed. Therefore, there are problems such as an increase in cost. In order to avoid these problems, there is a demand for a method of manufacturing an electromagnetic shielding glass that can be provided at low cost by forming a conductive thin film at low cost.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic wave which can be manufactured at low cost and has excellent practical properties such as adhesion and long-term durability with glass as a base material in view of the above situation. An object of the present invention is to provide a method for manufacturing a shield glass.

[0004]

SUMMARY OF THE INVENTION The inventor of the present invention does not need large-scale capital investment, and therefore has high economic efficiency, high productivity,
In addition, as a result of intensive studies on a method for producing an electromagnetic wave shielding glass having excellent practical performance, a metal compound which has volatilization or sublimation, and forms a conductive metal oxide by a chemical reaction, and if necessary The present inventors have found that the metal oxide can be produced by discharging a metal compound of a metal to be doped into the metal oxide onto a glass substrate and forming a conductive metal oxide thin film layer, thereby completing the present invention. The chemical reaction is a chemical reaction with a compound in the atmosphere, for example, water, oxygen, and the atmosphere for releasing the metal compound is an atmospheric pressure atmosphere,
That is, if the pressure is normal, there is no need to apply a vacuum as compared with a PVD method such as a sputtering method for forming a conductive inorganic thin film such as silver. Therefore, there is no need for large equipment.
In addition, the rate of forming the inorganic thin film is extremely high because the concentration of the inorganic substance sprayed on the base material is higher than in the case where the vacuum is applied. Therefore, the inorganic thin film can be formed at high speed, and the electromagnetic wave shielding glass can be manufactured at low cost.

That is, the present invention relates to one or more metal compounds which have a volatilization or sublimation property and form a metal oxide by a chemical reaction, preferably a reaction with a compound in the atmosphere, and if necessary, a metal compound. The metal compound of the metal to be doped into the metal oxide is preferably released together with a gaseous medium such as nitrogen gas onto a glass substrate, preferably under an atmospheric pressure atmosphere, and at least one layer of conductive material is formed on the glass substrate. The present invention relates to a method for producing an electromagnetic wave shielding glass, comprising forming a conductive metal oxide thin film layer.

Hereinafter, the present invention will be described in detail. First, the raw materials used in the present invention will be described. The glass as the base material is not particularly limited as long as it is generally called glass, and examples thereof include soda-lime glass, potash glass, lead glass, borosilicate glass, and silicate glass. As the shape of the glass substrate, any shape such as a plate shape, a fiber shape, a bead shape and the like can be used. Among them, a plate shape in which the need for an electromagnetic wave shield is particularly high, that is, a plate glass is preferable. In the case of sheet glass, the thickness is not particularly limited, but a commercially available thickness, that is, a thickness of 1 mm or more can be used.

As the metal compound which is a raw material of the present invention, a metal compound which forms an oxide by a chemical reaction is used. Specifically, this metal compound is, for example, volatilized or sublimated,
When it is released, it may be partially reacted with oxygen or moisture present in the atmosphere or a chemical substance intentionally used, but one that mainly forms a metal oxide is used.
Usually, no catalyst is preferable, but a metal oxide may be formed in the presence of a catalyst. An example is given to explain the principle in an easy-to-understand manner. For example, tetraalkoxy tin is used as a metal compound, which is heated and volatilized at 150 ° C.
When heated to 0 ° C. and released into the atmosphere without a catalyst, it reacts with moisture in the atmosphere on the surface of the substrate to form a metal oxide mainly composed of tin oxide.

It is presumed that most of this reaction is probably based on the following chemical reaction. Sn (OR) ₄ + 2H ₂ O → SnO ₂ + 4ROH The main metal in the metal compound is not particularly limited as long as its oxide shows conductivity. In order to exhibit electromagnetic wave shielding properties, the surface resistance of the manufactured electromagnetic wave shielding glass is preferably 10 ³ Ω / □ or less. Further 10 ²
It is more preferably Ω / □ or less. Further, when the electromagnetic wave shielding glass manufactured in the present invention is used as a window glass of a building or the like, it is necessary to see the outside scenery and the like. Although the electromagnetic wave shielding glass produced in the present invention is not necessarily required to be transparent, those having excellent transparency are more preferable. Therefore, the total light transmittance of the electromagnetic wave shielding glass of the present invention is preferably 50% or more. More preferably, it is at least 60%. Examples of the main metal in the metal compound include IIB and III in the periodic table.
A, IIIB, IVA, and IVB can be used alone or in combination of two or more.
Among them, a single material selected from Zn, Cd, In, Sn and Ti or a combination of two or more thereof is preferable because of good transparency and good conductivity.

The metal oxide can be doped with a metal as required to increase the conductivity. For example, by doping zinc oxide with aluminum, its conductivity can be increased to a level of 10 ⁻⁴ Ω / □. To illustrate the principle in an easy-to-understand manner, for example, for example, using zinc acetylacetonate and aluminum acetylacetonate as metal compounds, heating and volatilizing the mixture at 150 ° C., and using nitrogen gas as a gaseous medium, When the glass substrate is heated to 500 ° C. and released into the atmosphere without a catalyst, on the surface of the substrate, a metal mainly composed of zinc oxide reacts with the moisture in the atmosphere and is presumed to be based on the following. Form an oxide. At this time, it is presumed that aluminum is taken in the crystal structure of zinc oxide.

[0010] Zn (acac) ₂ + H ₂ O → ZnO + 2
acac (acetylacetone) Examples of metals to be doped as described above include IIB, IIIA, IIIB, IVA, IVB, VA,
VB and VIA can be used alone or in combination of two or more. Among them, especially Y, B, Al, G
a, In, Ti, Zr, Sn, Sb, Mo, WZn, C
A single or a combination of two or more selected from d, In, Sn, and Ti is preferred because it has a high effect of increasing the conductivity of the metal oxide.

The metal compound forming the metal oxide is not particularly limited as long as it is a compound which reacts with oxygen, moisture or the like to form a metal oxide when it is volatilized or sublimated and discharged from the nozzle. Examples thereof include the above-mentioned metal alkyl compounds, alkenyl compounds, phenyl or alkylphenyl compounds, alkoxide compounds, halogen compounds, acetylacetonate compounds and EDTA compounds. These metal compounds can be used alone, or a plurality of compounds can be used in combination even for the same metal. Examples of the metal compound of the metal that is doped into the metal oxide as necessary include, but are not limited to, the above-mentioned metal alkyl compounds, alkenyl compounds, phenyl or alkylphenyl compounds, alkoxide compounds, halogen compounds, and acetylacetonate compounds. And EDTA compounds.

The method of discharging the metal compound from the nozzle by volatilization or sublimation is not necessarily limited to this, but it is preferable to discharge the metal compound together with the gaseous medium. The reason for this is that the method of releasing together with a gaseous medium is capable of controlling the release amount of the metal compound to a constant amount. The gaseous medium is not particularly limited as long as it does not react with the metal compound used. Examples thereof include an inert gas such as a nitrogen gas and an argon gas, a carbon dioxide gas, an organic fluorine-based gas, and hexane and heptane. And the like. However, safety,
An inert gas is preferable from the viewpoint of economy. Among them, nitrogen gas is most preferable from the viewpoint of economy.

Next, the method for producing the electromagnetic wave shielding glass of the present invention will be specifically described. The present invention relates to one or more metal compounds which have a volatilization or sublimation property and form a metal oxide by a chemical reaction, preferably by a chemical reaction with a compound in the atmosphere, and if necessary, the metal oxide. For example, as shown in FIG. 1, a metal compound of a metal to be doped is volatilized or sublimated in a heating tank,
Preferably, a gaseous medium is emitted as a carrier gas from a slit and then sprayed onto a glass substrate to form a conductive film made of a metal oxide on the surface of the glass substrate.

When the present invention is produced by a method in which a metal oxide is formed by a chemical reaction with a compound such as moisture or oxygen in the atmosphere, the metal compound is volatilized or dissolved in a state where oxygen and moisture are absent or extremely small. It is heated to sublimation temperatures or higher and is released with entrained gaseous media in the absence or very little oxygen and moisture. The reason why oxygen and water in the metal compound or the gaseous medium are not present or are extremely small is to prevent a reaction due to a metal oxide in the apparatus before the release and a trouble such as clogging. However, depending on the type of the metal compound used, the reaction rate of the metal compound to the oxide may be extremely low only by discharging the metal compound to the atmosphere from an outlet such as a slit. In this case, oxygen, moisture, or a catalyst for increasing the reaction speed (eg, volatile acid, alkali, etc.) should coexist in the gaseous medium or in the heating tank so as not to cause clogging in the apparatus. There is also. The metal compound to be released may be one kind or a mixture. It is possible to mix and volatilize, but after mixing the volatilized material, it is also possible to spray the mixture onto the base material.

The temperature of the metal compound to be released is not particularly limited as long as it is generally equal to or higher than the temperature at which the metal compound volatilizes, but the temperature is generally 100 to 500 ° C. The substrate temperature is not particularly limited as long as the released metal compound reacts with a compound in the air on the surface of the glass substrate to form a metal oxide.
Often performed at ~ 800 ° C. This temperature setting is an important factor that determines the adhesion to the glass substrate. There are two main methods for setting temperature conditions. One is to make the release temperature higher than the glass substrate temperature. Another method is to lower the release temperature below the glass substrate temperature. In the former, when the metal compound is released from the slit, metal oxide fine particles are formed by a chemical reaction immediately after the release,
The transparent conductive film is formed in such a manner that the high-temperature metal oxide particles are stacked on the glass substrate. In the latter, a metal oxide is formed by a chemical reaction on the surface of the glass substrate, and the metal oxide grows on the metal oxide to form a conductive film. In general, the former method is not necessarily preferable in terms of adhesion to a glass substrate because the former method results in an aggregate of particles. The latter method has better adhesion.

The distance between the outlet of the metal compound and the surface of the glass substrate is usually 50 cm or less. Although it depends on the shape of the outlet of the metal compound, when the diameter is 50 cm or more, the metal compound is not effectively converted to the metal oxide, and the efficiency tends to be poor. The atmosphere for releasing the metal compound may be under reduced pressure, under normal pressure or under pressure. However, when the process is performed under a high degree of reduced pressure, for example, under an ultra-vacuum, the production rate of the metal oxide is low, and the productivity is lacking. Although there is no problem with the growth rate of the metal oxide carried out under pressure, it is not a preferable direction because equipment for pressurization is required. Although not limited to this,
Usually, it is preferable to carry out at 0.1 to 10 atm. However, in general, it is most preferable to carry out the reaction under an atmospheric pressure atmosphere, that is, at normal pressure. This method does not require large-scale equipment for industrial production, and the growth rate of the metal oxide is in a range that can be put to practical use. The present invention
The conductive metal oxide thin film layer to be formed may be a single layer or may be sequentially and sequentially laminated to form a multilayer of the same type or different types of conductive metal oxide thin film layers. At this time, an inorganic layer or an organic layer having a function other than the conductive function may be provided on the conductive metal oxide thin film layer or between the conductive metal oxide thin film layer and the glass substrate.

The thickness of the conductive metal oxide thin film layer of the electromagnetic wave shielding glass thus manufactured is usually 20 μm.
m, preferably 10 μm or less, more preferably 2 μm
m or less. A single layer or a multilayer is preferably within this range. In general, when the thickness is too large, defects such as cracks tend to easily occur in the conductive metal oxide thin film layer, which is not preferable. Generally, it is preferably 20 μm or less. or,
The lower limit is not particularly limited as long as the conductive function is exhibited. Usually, it is preferable that it is 0.01 μm or more.

The electromagnetic wave shielding glass produced by the present invention exhibits good electromagnetic wave shielding properties. In addition, since the inorganic thin film is a metal oxide and the main component of glass is also an oxide, it has excellent mutual adhesion, and since the inorganic thin film itself is a finally stable metal oxide, it is stable for a long time. Also excellent in nature. This electromagnetic wave shielding glass can be used for windows of buildings, condominiums, general houses, cathode ray tubes or front panels of televisions and plasma displays, and the like. Further, the fibrous glass can be used as a heat insulating material and a shielding material by making it into a nonwoven fabric.

[0019]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In addition, the measuring method of the electromagnetic wave shielding property is described by Anritsu Corporation.
The measurement was performed using a spectrum analyzer MS623A measuring device, a tracking generator MH628A, and an anechoic chamber. A 100 × 100 mm square sample was measured in a frequency range of 100 to 1000 MHz.

(Example 1) The dry nitrogen introduction line of FIG.
Using equipment comprising a metal compound heating tank and a slit-shaped outlet, a mixture of indium trimethylacetyl acetate and tetraethoxytin (molar ratio 9) was added to the heating tank.
1.5 / 8.5). The heating tank is heated to 150 ° C, and the heating piping and slits are also heated by the heater.
It was heated to 50 ° C and the blowing temperature was set at 150 ° C.
A 5 mm-thick glass plate (soda-lime glass plate) was set at a position 5 cm below the blowing slit, and heated to 500 ° C. Dry nitrogen gas was introduced into the heating tank, and a mixture of indium trimethylacetyl acetate and tetraethoxytin was volatilized, released into an atmospheric pressure atmosphere, and sprayed on the surface of the glass plate. It reacted with water in the air on the surface of the glass plate, and a transparent conductive film made of tin-doped indium oxide was formed on the surface of the glass plate. The thickness of this transparent conductive film was controlled by the amount of dry nitrogen gas introduced and the moving speed of the glass plate, and was about 0.5 μm. As a result of measuring the conductivity of this tin-doped indium oxide (ITO) transparent conductive film, the surface resistance was 0.01 Ω / □.
The adhesion between the ITO conductive film and the glass substrate was good without peeling off at the interface even when the surface was scratched with a cutter knife. The evaluation result of the electromagnetic wave shield of this glass was about 50 dB at an attenuation value of 800 MHz.

(Embodiment 2) The dry nitrogen introduction line of FIG.
Using a facility comprising a metal compound heating tank and a slit-shaped outlet, a mixture of zinc acetylacetonate and aluminum acetylacetonate (molar ratio 95
/ 5). The heating tank is heated to 150 ° C, and the heating piping and slits are also heated by the heater.
It was heated to 50 ° C and the blowing temperature was set at 150 ° C.
A 5 mm-thick glass plate (soda-lime glass plate) was set at a position 5 cm below the blowing slit, and heated to 500 ° C. Dry nitrogen gas was introduced into the heating tank, and a mixture of zinc acetylacetonate and aluminum acetylacetonate was volatilized, released to the atmosphere of atmospheric pressure, and sprayed on the surface of the glass plate. Reacted with water in the air on the surface of the glass plate, and a conductive film composed of zinc oxide doped with aluminum was formed on the surface of the glass plate. The thickness of this transparent conductive film was controlled by the amount of dry nitrogen gas introduced and the moving speed of the glass plate, and was about 1.0 μm. As a result of measuring the conductivity of this aluminum-doped zinc oxide conductive film, the surface resistance was 0.001 Ω / □. Also, the adhesion between the conductive film and the glass substrate was good without peeling off at the interface even if the surface was scratched with a cutter knife. The evaluation result of the electromagnetic wave shield of this glass was 800 MHz.
The attenuation value of z was about 55 dB.

[0022]

EFFECTS OF THE INVENTION One or more metal compounds which have volatilization or sublimability and form a metal oxide by a chemical reaction, preferably a chemical reaction with a compound in the atmosphere, and if necessary, the metal oxide The method of the present invention for releasing a metal compound of a metal to be doped into a glass substrate, preferably in a gaseous medium, under an atmospheric pressure atmosphere to form a conductive metal oxide thin film on a glass substrate is economical. It is possible to provide an electromagnetic shielding glass having high performance, high productivity, and excellent practical performance.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a process of forming an inorganic thin film on a substrate.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4D075 CA50 DA06 DB13 DC01 EB01 EC02 EC10 4F100 AA17B AA18B AA19B AA21B AA25B AA27B AA28B AA29B AG00A BA02 BA07 EH66 GB41 JD08 JG04B JL02 Y20 BA11 BA18 ABA BAA BAA BA21 BA22 BA26 BA42 BA53 BA54 BA55 CA06 FA10 JA06 KA25 LA01 LA02 LA11

Claims (11)

[Claims] 1. A glass substrate comprising one or more metal compounds having volatility or sublimability and forming a metal oxide by a chemical reaction, and a metal compound of a metal doped into the metal oxide as required. A method for producing an electromagnetic wave shielding glass, comprising: forming a conductive metal oxide thin film on a substrate; 2. The conductive metal oxide thin film has a surface resistance of 1
The method for producing an electromagnetic wave shielding glass according to claim 1, wherein the resistance is not more than 0 ³ Ω / □. 3. The method for producing an electromagnetic wave shielding glass according to claim 1, wherein the total light transmittance is 50% or more. 4. The method for producing an electromagnetic shielding glass according to claim 1, wherein the metal compound is released together with the gaseous medium. 5. The method according to claim 1, wherein the chemical reaction is caused by a chemical reaction with a compound in the atmosphere. 6. The method for producing an electromagnetic wave shielding glass according to claim 1, wherein the atmosphere in which the metal compound is released is an atmospheric pressure atmosphere. 7. The main metal in the metal compound forming an oxide is represented by IIB, IIIA, IIIB, IV in the periodic table.
The method for producing an electromagnetic shielding glass according to any one of claims 1 to 6, wherein one or more types are selected from A and IVB. 8. The production of the electromagnetic shielding glass according to claim 7, wherein the main metal in the metal compound forming the oxide is at least one selected from Zn, Cd, In, Sn and Ti. Method. 9. The method of claim 1, wherein the optionally doping metal comprises IIB, IIIA, IIIB, IVA, IVB,
The method for producing an electromagnetic wave shielding glass according to any one of claims 1 to 8, wherein at least one kind is selected from VA, VB, and VIA. 10. The metal which is optionally doped is
Y, B, Al, Ga, In, Ti, Zr, Sn, Sb,
The method for producing an electromagnetic wave shielding glass according to claim 9, wherein one or more types are selected from Mo and W. 11. A metal compound forming a metal oxide and, if necessary, a metal compound of a metal doped into the metal oxide, are alkyl compounds, alkenyl compounds, phenyl or alkylphenyl compounds, alkoxide compounds, halogen compounds, acetyl compounds. The method for producing an electromagnetic wave shielding glass according to any one of claims 1 to 10, wherein the method is selected from an acetonate compound and an EDTA compound.