JP2003073583A - Method for producing coating liquid for forming electrically conductive transparent coating film and substrate and display device provided with electrically conductive transparent coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the production of a coating liquid for forming a electrically conductive transparent coating film enabling the formation of a transparent conductive film having a surface resistance of as low as about 10<2> to 10<8> Ω/cm<2> , exhibiting excellent antistaticity, antireflection property and electromagnetic shielding property, having high transparency and reliability of the coating film, giving flat surface free from the defect of appearance such as streak mark and spot and having excellent production reliability. SOLUTION: The coating liquid for forming a transparent conductive film contains electrically conductive fine particles consisting of (A) indium oxide fine particles and (B) tin oxide fine particles and a polar solvent. The coating liquid is produced by uniformly mixing and dispersing the indium oxide fine particles (A) and the tin oxide fine particles (B) in the polar solvent at a mixing weight ratio (A/B) of the indium oxide particles (A) to the tin oxide particles (B) in the electrically conductive fine particles of 98/2 to 60/40. The uniform mixing and dispersion of the conductive fine particles in the polar solvent is carried out in a manner to obtain the dispersion having a viscosity of 1.0-5 cp at a conductive particle concentration of 20 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a coating liquid for forming a transparent conductive film, in which conductive fine particles are dispersed in a polar solvent,
The present invention also relates to a transparent conductive film-coated substrate having a transparent conductive film formed using the coating liquid, and a display device including the substrate.

[0002]

2. Description of the Related Art Conventionally, for the purpose of antistatic and antireflection of the surface of a transparent substrate such as a display panel such as a cathode ray tube, a fluorescent display tube, a liquid crystal display panel, etc. It has been performed to form a transparent film having an antireflection function. Further, it is known that electromagnetic waves are emitted from a cathode ray tube and the like, and in addition to the conventional antistatic and antireflection properties, it is desired to shield these electromagnetic waves and the electromagnetic field formed by the emission of the electromagnetic waves. .

As one of the methods of shielding these electromagnetic waves and the like, there is a method of forming a conductive coating for shielding electromagnetic waves on the surface of a display panel such as a cathode ray tube. It is sufficient for the antistatic conductive film to have a surface resistance of at least about 10 ⁸ Ω / □, whereas for the conductive film for electromagnetic shielding, 10 ² to 10 ⁴ Ω / It was necessary to have a low surface resistance such as □.

A conductive film having a low surface resistance is
If a conventional coating solution containing a conductive oxide such as Sb-doped tin oxide or Sn-doped indium oxide is used, it is necessary to make the film thicker than in the case of the conventional antistatic coating. However, since the antireflection effect is not exhibited unless the thickness of the conductive coating is set to about 10 to 200 nm, conventional conductive oxides such as Sb-doped tin oxide or Sn-doped indium oxide have a low surface resistance, There is a problem in that it is difficult to obtain a conductive coating film that is excellent in electromagnetic wave shielding properties and also in antireflection.

Further, as one of the methods for forming a conductive film having a low surface resistance, a coating film containing metal fine particles is formed on the surface of a substrate by using a coating liquid for forming a conductive film containing metal fine particles such as Ag. There is a way. In this method, as a coating liquid for forming a coating film containing metal fine particles, a colloidal metal fine particle dispersed in a polar solvent is used. In such a coating liquid, in order to improve the dispersibility of the colloidal metal fine particles, the surface of the metal fine particles is polyvinyl alcohol,
It is surface-treated with an organic stabilizer such as polyvinylpyrrolidone or gelatin. However, a conductive coating formed using such a coating solution for forming a coating containing metal fine particles has a large grain boundary resistance because the metal fine particles come into contact with each other through a stabilizer in the coating, and the surface resistance of the coating is large. Sometimes did not go down. For this reason, after film formation, it is necessary to bake at a high temperature of about 400 ° C. to decompose and remove the stabilizer, but if it is baked at a high temperature to decompose and remove the stabilizer, fusion and agglomeration of metal fine particles occur. However, there is a problem that the transparency and haze of the conductive coating are reduced. Further, in the case of a cathode ray tube or the like, there is a problem that it deteriorates when exposed to high temperature.

Further, unlike the above-mentioned conductive oxide, the metal fine particles originally do not transmit light. Therefore, the conductive coating formed by using the metal fine particles depends on the density, the film thickness, etc. of the metal fine particles in the conductive coating. There was also a problem that transparency was lowered. Further, in the conventional transparent conductive coating film containing fine metal particles such as Ag, the salt water resistance and the oxidation resistance are low, the metal is oxidized,
There is a problem that particle growth due to ionization or corrosion may occur in some cases, the conductivity and light transmittance of the coating film decrease, and the display device lacks reliability.

Further, a coating solution used for forming the above-mentioned conventional transparent conductive film, particularly fine particles having high conductivity such as metal fine particles for forming a low surface resistance transparent conductive film for shielding electromagnetic waves. The coating solution containing is insufficient in stability, the surface of the obtained transparent conductive film is not always smooth, and streaks or spots may appear on the outer surface of the product, resulting in poor product yield. There was a problem of lowering. Further, when the conventional coating liquid is used, there is a problem that the defects of appearance are apt to occur due to the influence of the cleanliness of the substrate and the manufacturing reliability is poor.

Further, a colorant such as carbon fine particles may be added to the transparent conductive film to control the transmittance to improve the contrast, but the conductive fine particles are opposite to the colorant. In the case of having a particle surface potential, conductive fine particles and colorant particles adhere to each other and aggregate,
The stability of the coating liquid is low, and it is practically difficult to use as a coating liquid. For example, when the conductive fine particles are the above-mentioned indium oxide-based fine particles, carbon fine particles cannot be blended, and therefore a display device including a transparent conductive film-coated substrate having excellent contrast could not be obtained. .

[0009]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, has a low surface resistance of about 10 ² to 10 ⁸ Ω / □, and has antistatic property, antireflection property and electromagnetic shielding property. In addition to being excellent in transparency and reliability, the transparent surface has a smooth surface, there are no streaks or spot-like appearance defects, and transparent conductive film that can be formed with excellent manufacturing reliability. An object of the present invention is to provide a method for producing a coating liquid for forming a conductive film, a substrate with a transparent conductive film, and a display device including the substrate.

[0010]

SUMMARY OF THE INVENTION The method for producing a coating liquid for forming a transparent conductive film according to the present invention is a transparent conductive material containing indium oxide fine particles (A) and tin oxide fine particles (B) as conductive fine particles, and a polar solvent. In the method for producing a coating liquid for forming a coating film, the mixing ratio (A / B) of indium oxide fine particles (A) and tin oxide fine particles (B) in the conductive fine particles is 98/2 to 60/40.
It is characterized by being uniformly mixed and dispersed in a polar solvent in the range of (weight ratio).

In the present invention, the viscosity of the dispersion when the conductive fine particles are dispersed in a polar solvent is uniform so that the viscosity is within the range of 1.0 to 5 cp when the concentration of the conductive fine particles is 20% by weight. It is preferable to mix and disperse. The indium oxide-based fine particles (A) have an average particle diameter of 2 to 200.
nm, and the average particle diameter of the tin oxide-based fine particles (B) is 2
It is preferably in the range of ˜200 nm.

The indium oxide-based fine particles (A) are indium oxide, indium oxide doped with Sn or F, and the tin oxide-based fine particles (B) are tin oxide, Sb,
It is preferred that F or P is doped tin oxide. In the production method according to the present invention, after the conductive fine particles are dispersed, fine particle carbon black and / or titanium black may be further dispersed as a colorant.

The coating liquid for forming a transparent conductive film according to the present invention is characterized by being manufactured by the above method. The substrate with a transparent conductive film according to the present invention, a substrate, a transparent conductive film containing the conductive fine particles on the substrate, provided on the transparent conductive film, than the transparent conductive film A transparent conductive film having a low refractive index, which is formed by applying the transparent conductive film-forming coating liquid produced by the above method onto the surface of a substrate.

The display device according to the present invention is characterized by including a front plate composed of the base material with the transparent conductive film, and the transparent conductive film being formed on the outer surface of the front plate.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be specifically described below. Method for Manufacturing Coating Liquid for Forming Transparent Conductive Film First, a method for manufacturing a coating liquid for forming a transparent conductive film according to the present invention will be described. The method for producing a coating liquid for forming a transparent conductive film according to the present invention is the indium oxide-based fine particles (A).
And tin oxide fine particles (B) are uniformly mixed and dispersed in a polar solvent.

Conductive Fine Particles The conductive fine particles used in the present invention are indium oxide fine particles (A) and tin oxide fine particles (B), and both are uniformly mixed and dispersed in the coating solution according to the present invention. Has been done. As the indium oxide-based fine particles (A), conventionally known indium oxide or Sn or F-doped indium oxide is used. Such indium oxide-based fine particles (A) have high conductivity among the oxide-based conductive fine particles, and the resulting transparent conductive coating has excellent antistatic performance and electromagnetic wave shielding performance, and also has a transparent conductive property using metal fine particles. It has excellent transparency unlike the coating.

As the tin oxide type fine particles (B), tin oxide, tin oxide doped with Sb, F or P is used. The indium oxide-based fine particles (A) have an average particle diameter of 2 to 200 nm, preferably 5 to 150 nm. Indium oxide fine particles (A)
When the average particle size is less than 2 nm, the surface resistance of the particle layer is rapidly increased, and it may not be possible to obtain a coating having a low resistance value to the extent that the object of the present invention can be achieved.

When the average particle diameter of the indium oxide fine particles (A) exceeds 200 nm, the particles are large and the number of contact points between the particles is reduced, so that sufficient conductivity may not be obtained. In addition, the film strength and the adhesion to the substrate may decrease, and the haze of the obtained transparent conductive film may increase. Next, the tin oxide-based fine particles (B) have an average particle diameter of 2 to
It is desirable to be in the range of 200 nm, preferably 5-150 nm.

The average particle size of the tin oxide fine particles (B) is 2
If it is less than nm, the particles are too small and the tendency to aggregate becomes strong, and depending on the mixing amount, the effect of improving the stability of the coating solution may not be obtained, and on the contrary, the stability may be hindered. There is. The average particle size of the tin oxide fine particles (B) is 2
If it exceeds 00 nm, the particle size may be too large and the effect of improving the stability of the coating solution may not be obtained.
Therefore, a defect in appearance may occur.

The average particle diameters of the indium oxide type fine particles (A) and the tin oxide type fine particles (B) may be the same or different. Mixing ratio (A / B) of indium oxide fine particles (A) and tin oxide fine particles (B) in the coating liquid
Is (weight ratio), 98/2 to 60/40, preferably 90/10 to 70/30
It is desirable to be in the range of.

When the content of the indium oxide type fine particles (A) is less than 60% by weight, the surface resistance of the obtained conductive film may be 10 ⁴ Ω / □ or more and a sufficient electromagnetic wave shielding effect may not be obtained. When the content of the indium oxide-based fine particles (A) exceeds 98% by weight, the ratio of the tin oxide-based fine particles (B) is small, and thus the effect of improving the stability and the effect of improving the manufacturing reliability are achieved. May not be obtained.

Polar Solvent The polar solvent used in the present invention includes water; alcohols such as methanol, ethanol, propanol, butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol and isopropyl glycol. Esters such as acetic acid methyl ester and acetic acid ethyl ester; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether; acetone, methyl ethyl ketone, Examples include ketones such as acetylacetone and acetoacetic acid ester. These may be used alone or in combination of two or more.

Production of Coating Liquid In the present invention, the above conductive fine particles are uniformly mixed and dispersed in a polar solvent using a uniform mixing device. When dispersed in a polar solvent, the solid concentration of the conductive particles in the polar solvent dispersion is preferably in the range of 15 to 25% by weight. If the solid content concentration in the dispersion is out of this range, homogenization may not be sufficient, and as a result, the stability of the obtained transparent conductive film-forming coating liquid is low, and it is possible to obtain using this coating liquid. The transparent conductive film lacks compactness and the strength of the film is low, and the above-mentioned defects in appearance (streaks, unevenness, light spots)
May occur.

The conductive fine particles may be dispersed by mixing dry powders of the conductive fine particles (A) and (B) and then dispersing them in a polar solvent. A polar solvent dispersion liquid and a polar solvent dispersion liquid of tin oxide fine particles (B) may be prepared in advance and mixed (A) and mixed so that the solid content concentration after mixing is in the range of 15 to 25% by weight. . In particular, the latter method of mixing the polar solvent dispersion liquid of the indium oxide fine particles (A) and the polar solvent dispersion liquid of the tin oxide fine particles (B) is preferable because it allows more uniform mixing.

The solid content concentration of each dispersion liquid of indium oxide fine particles (A) and tin oxide fine particles (B) is particularly limited as long as the solid content concentration of the dispersion liquid is in the range of 15 to 25% by weight. Although not a thing, it is suitable to use about 10 to 30% by weight in terms of concentration adjustment. When the mixing and dispersion of the indium oxide-based fine particles (A) and the tin oxide-based fine particles (B) are insufficient and uneven,
Since the indium oxide-based fine particles (A) and the tin oxide-based fine particles (B) have different surface potentials, the particles adhere to each other and agglomerate, the stability of the coating liquid decreases, and gelation occurs. However, the transparent conductive coating film obtained by using such a coating liquid lacks the denseness and the strength of the film is low, and the above-mentioned appearance defects may occur.

When the indium oxide-based fine particles (A) and the tin oxide-based fine particles (B) are sufficiently uniformly mixed, the viscosity is low when the solid content concentration of the dispersion liquid is 15 to 25% by weight (solid content: The concentration is 20% by weight and the viscosity is 1 to 5 cp),
As described above, although the indium oxide-based fine particles (A) and the tin oxide-based fine particles (B) have different surface potentials, they do not aggregate and tend to improve the stability. Therefore, the transparent conductive film obtained by using such a coating solution is dense, the surface of the film is flat, and there are no defects (streaks, unevenness, light spots) in appearance, and the manufacturing reliability is excellent.

The method for uniformly mixing and dispersing both conductive fine particles is not particularly limited, but a mixing device such as a sand mill, a colloid mill, a ball mill, an ultrasonic homogenizer, a vent shaker or a nanomizer is preferably adopted. . When uniformly mixed and dispersed using such a uniform mixing device, the viscosity at the solid content concentration of the dispersion liquid is 20 wt% is in the range of 1.0 to 5 cp, and further 1.0 to 3 cp.
A conductive fine particle dispersion liquid having a cp range can be prepared. Compared with conventional metal fine particle dispersion liquid and metal oxide fine particle molecular dispersion liquid, this dispersion liquid has a high solid content concentration,
The viscosity is extremely low. The reason for this is not clear, but when the indium oxide-based fine particles (A) and the tin oxide-based fine particles (B) are simply mixed, the surface charges opposite to each other are neutralized, and the particles become chained or gelled. The viscosity increases, but it does not become a chain by uniformly mixing and dispersing, and for example, a new particle group in which tin oxide fine particles (B) are aggregated around indium oxide fine particles (A) is formed. However, it is considered that a small number of large particles are apparently dispersed, and as a result, the viscosity of the dispersion becomes low.

The conductive fine particle dispersion liquid thus prepared can be used as it is as a coating liquid, but if necessary, it may be diluted with a polar solvent or concentrated to adjust the solid content concentration. Good. In particular, when used as a coating liquid for forming a conductive film, the total amount of the conductive fine particles (A) and (B) is 0.1 to 7% by weight, preferably 0.5 to
It is preferably contained in the range of 5% by weight.

When the content of the conductive fine particles in the coating solution for forming the transparent conductive coating film is less than 0.1% by weight, the film thickness of the coating film obtained may be small, and therefore sufficient conductivity cannot be obtained. Sometimes. When the conductive fine particles exceed 7% by weight, the conductive fine particles may form secondary particles (aggregated particles or particles in a non-monodisperse state linked in a chain) in the coating liquid. If the amount is large, the denseness of the film may decrease, the film strength may decrease, and sufficient conductivity may not be obtained. Further, the coating may become thick and the light transmittance may be lowered to deteriorate the transparency, or the flatness of the coating surface may be lowered to cause streaks, unevenness and the like to deteriorate the appearance.

If necessary, other additives (metal fine particles, carbon black, matrix, etc.) and a solvent (for concentration adjustment) may be added to and mixed with the coating liquid thus obtained. When mixing the other additives and the solvent, the above-mentioned mixing device may be used. Further, in the present invention, as the metal fine particles, Au, Ag, P
d, Pt, Rh, Ru, Cu, Fe, Ni, Co, Sn, Ti, I
At least 1 selected from metals such as n, Al, Ta and Sb
Examples include ones or two or more metals. Preferred combinations of two or more metals are Au-Cu and Ag.
-Pt, Ag-Pd, Au-Pd, Au-Rh, Pt-Pd, Pt-R
h, Fe-Ni, Ni-Pd, Fe-Co, Cu-Co, Ru-Ag, A
u-Cu-Ag, Ag-Cu-Pt, Ag-Cu-Pd, Ag-Au-Pd,
Au-Rh-Pd, Ag-Pt-Pd, Ag-Pt-Rh, Fe-Ni-P
d, Fe-Co-Pd, Cu-Co-Pd and the like can be mentioned.

The amount of the fine metal particles added is preferably 0.05 to 10% by weight, and more preferably 0.05 to 5% by weight, based on the conductive fine particles (total of A and B). When such metal fine particles are contained, the conductivity of the conductive coating is improved and the electromagnetic wave shielding ability is improved, and in addition, the light transmittance can be controlled by using the metal fine particles, and therefore, the contrast is improved. And is superior in salt water resistance and oxidation resistance as compared with the case of using only metal fine particles.

The coating solution obtained by the method according to the present invention has excellent stability and is not always necessary. However, as described above, when the metal fine particles are added to the conductive fine particles, the metal fine particles are dispersed. In order to improve the property, an organic stabilizer may be added to the coating liquid for forming the transparent conductive film.
Specifically as such an organic stabilizer, gelatin,
Polyvinyl alcohol, polyvinylpyrrolidone, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,
Examples thereof include polyvalent carboxylic acids such as sebacic acid, maleic acid, fumaric acid, phthalic acid, citric acid, salts thereof, heterocyclic compounds and mixtures thereof.

Such an organic stabilizer is used for the metal fine particles 1
It is desirable to add 0.005 to 0.5 parts by weight, preferably 0.01 to 0.2 parts by weight, based on parts by weight.
When the amount of the organic stabilizer is less than 0.005 part by weight, sufficient dispersibility of the metal fine particles cannot be obtained, and when it is more than 0.5 part by weight, the conductivity may be hindered. Examples of the colorant include fine particle carbon black and / or titanium black, and dyes and pigments may be added. When such a coloring agent is added, a coating liquid for a display device having excellent contrast can be obtained.

In particular, in the present invention, finely divided carbon black and / or titanium black is used as an indium oxide-based conductive fine particle (A) having a surface potential opposite thereto.
Although it will be added to the dispersion liquid, since the tin oxide-based conductive fine particles (B) are mixed in a predetermined amount and uniformly,
Since the added fine particles of carbon black, titanium black, etc. do not aggregate and the stability of the coating solution is not impaired, it is dense and has good adhesion to the substrate,
It is possible to form a transparent conductive coating having a flat surface and no defect in appearance.

The average particle size of the particulate carbon black and / or titanium black added is from 2 to 200 n.
m, preferably 5 to 150 nm. It is desirable to add such a colorant in an amount of 0.15 parts by weight or less based on 100 parts by weight of the total of the indium oxide based particles (A) and the tin oxide based particles (B). When the blending amount of the colorant is 0.15 parts by weight or less, the light transmittance can be adjusted without significantly lowering the conductivity of the transparent conductive coating, and the contrast can be improved.

When the above-mentioned additives such as colorants, dyes and pigments are added, the total solid content concentration (including conductive fine particles) in the coating liquid for forming a transparent conductive film is the fluidity of the liquid. From the viewpoint of dispersibility of granular components such as conductive fine particles in the coating liquid, the content is 15% by weight or less, preferably 0.1% by weight or less.
It is preferably 15 to 5% by weight. Further, as the matrix-forming component, those made of silica are preferable, and specifically, a hydrolyzed polycondensate of an organosilicon compound such as an alkoxysilane or a silicic acid polymer obtained by dealkalizing an alkali metal silicate aqueous solution is used. Examples thereof include a condensate or a resin for paint. This matrix-forming component is a solid content per 1 part by weight of conductive fine particles,
It is desirable to add in an amount of 0.01 to 0.5 parts by weight, preferably 0.03 to 0.3 parts by weight. Such a matrix-forming component functions as a binder for the conductive fine particles after the film formation.

By using the coating liquid for forming the transparent conductive coating film obtained as described above, the conductive fine particles are uniformly dispersed, the pot life is long, and the surface of the transparent conductive coating film obtained is smooth. In addition, there is no appearance defect such as streak or unevenness, and the manufacturing reliability of the transparent conductive film-coated substrate is excellent. Further, since a transparent conductive film having a surface resistance of approximately 10 ² to 10 ⁴ Ω / □ can be formed, charging is prevented, and electromagnetic waves and an electromagnetic field generated due to emission of electromagnetic waves are effectively shielded. be able to.

Since the conductive fine particles include oxide fine particles such as indium oxide conductive fine particles (A) and tin oxide conductive fine particles (B), the obtained transparent conductive film-coated substrate is Excellent manufacturing reliability, salt water resistance, oxidation resistance, and transparency. Further, it is also possible to add fine particles of carbon black, titanium black, etc. to the coating solution, which has been difficult to mix in the conventional indium oxide coating solution.

Substrate with Transparent Conductive Film Next, the substrate with a transparent conductive film according to the present invention will be specifically described. In the transparent conductive film-coated substrate according to the present invention, a transparent conductive film-forming coating obtained by the above-mentioned method is applied onto a substrate such as a film, sheet or other molded body made of glass, plastic, ceramic or the like. A transparent conductive coating formed from a liquid and a transparent coating formed on the transparent conductive coating.

As the conductive fine particles, the same as those mentioned above can be mentioned. [Transparent conductive coating] The thickness of the transparent conductive coating is 5 to 20.
The thickness is preferably in the range of 0 nm, preferably in the range of 10 to 150 nm, and the film thickness in this range makes it possible to obtain a substrate with a transparent conductive film having excellent antistatic properties and electromagnetic shielding properties.

If necessary, such a transparent conductive film may contain fine metal particles, a colorant, a matrix component, an organic stabilizer, and the like. Can be mentioned. [Transparent coating] In the substrate with a transparent conductive coating according to the present invention,
A transparent coating having a refractive index lower than that of the transparent conductive coating is formed on the transparent conductive coating.

The thickness of the transparent coating film at this time is 50 to 30.
It is preferably in the range of 0 nm, preferably 80 to 200 nm. When the thickness of the transparent film is less than 50 nm,
The strength and antireflection performance of the film may be poor. If the film thickness of the transparent film exceeds 300 nm, cracks may occur in the film or the strength of the film may be reduced, and the film may be too thick and the antireflection performance may be insufficient.

Such a transparent film is formed of, for example, an inorganic oxide such as silica, titania or zirconia, or a composite oxide thereof. In the present invention, the transparent coating is preferably a silica-based coating made of a hydrolyzed polycondensate of a hydrolyzable organosilicon compound or a silicic acid polycondensate obtained by dealkalizing an aqueous alkali metal silicate solution. The transparent conductive film-coated substrate having such a transparent film formed thereon has excellent antireflection performance.

The transparent coating has an average particle size of 5
To 300 nm, preferably 10 to 200 nm, and a refractive index of 1.28 to 1.42, preferably 1.2.
It is desirable to include low refractive index particles in the range of 8 to 1.40. The average particle size of the low refractive index particles used is appropriately selected according to the thickness of the transparent coating formed.

When the low refractive index particles have a refractive index of 1.42 or less, the obtained transparent conductive film-coated substrate has low bottom reflectance and luminous reflectance and exhibits excellent antireflection performance. You can The content of low refractive index particles in the transparent coating is 10 to 90% by weight, preferably 20 in terms of oxide.
It is desirable to be in the range of -80% by weight.

The low refractive index particles used in the present invention are not particularly limited as long as the average particle diameter and the refractive index are within the above ranges, and conventionally known particles can be used. For example, the composite oxide sol disclosed in Japanese Patent Application Laid-Open No. 7-133105 and the porous composite oxide particles having a coating layer disclosed in WO00 / 37359 can be preferably used.

Further, if necessary, the transparent film may contain additives such as fine particles, dyes and pigments made of a low refractive index material such as magnesium fluoride. [Manufacturing Method of Substrate with Transparent Conductive Coating] Next, a manufacturing method of the above-mentioned base material with a transparent conductive coating will be described. The above-mentioned substrate with a transparent conductive film is formed by coating and drying the above-mentioned coating liquid for forming a transparent conductive film containing conductive fine particles on the substrate to form a transparent conductive film, and then transparent on the fine particle layer. It can be manufactured by applying a coating liquid for forming a film to form a transparent film having a refractive index lower than that of the fine particle layer on the transparent conductive film. [Formation of transparent conductive coating] First, the transparent conductive coating forming coating solution is applied onto a substrate and dried to form a transparent conductive coating on the substrate.

As a method for forming a transparent conductive film,
For example, the coating liquid for forming a transparent conductive film is applied on a substrate by a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, or the like, and then at a temperature in the range of room temperature to about 90 ° C. dry. When the coating liquid for forming the transparent conductive film contains the above-mentioned matrix-forming component, the matrix-forming component may be cured.

For example, the film formed by applying the coating liquid for forming the transparent conductive film may be dried at the time of drying or after drying 15
Even if it is heated at 0 ° C or higher, or the uncured coating is irradiated with electromagnetic waves such as ultraviolet rays, electron rays, X-rays, and γ rays having a shorter wavelength than visible light, or exposed to an atmosphere of active gas such as ammonia. Good. By doing so, the hardening of the film-forming component is promoted, and the hardness of the film obtained is increased.

The film thickness of the transparent conductive film formed by the above method is 5 to 200 nm, more preferably 10 to 1
The range of 50 nm is desirable, and if the film thickness is within this range, it is possible to obtain a transparent conductive film-coated substrate having excellent antistatic properties and electromagnetic shielding properties. [Formation of transparent coating] In the present invention, a transparent coating having a refractive index lower than that of the fine particle layer is formed on the transparent conductive coating formed as described above.

The film thickness of the transparent coating is preferably in the range of 50 to 300 nm, preferably 80 to 200 nm, and in such a range, excellent antireflection property is exhibited. The method for forming the transparent coating is not particularly limited, and depending on the material of the transparent coating, a dry thin film forming method such as a vacuum evaporation method, a sputtering method, an ion plating method, or a dipping method or a spinner method as described above. A wet thin film forming method such as a spray method, a roll coater method, or a flexographic printing method can be used.

When forming the above-mentioned transparent film by a wet thin film forming method, a conventionally known coating liquid for forming a transparent film can be used. As such a transparent film forming coating solution,
Specifically, a coating liquid containing an inorganic oxide such as silica, titania or zirconia, or a composite oxide of these as a transparent film forming component is used. In the present invention, as a coating liquid for forming a transparent film, a hydrolytic polycondensate of a hydrolyzable organosilicon compound, or a silica-based transparent film forming coating containing a silicic acid solution obtained by dealkalizing an aqueous alkali metal silicate solution. The liquid is preferable, and it is particularly preferable that the liquid contains a hydrolytic polycondensate of an alkoxysilane represented by the following general formula [1]. The silica-based coating film formed from such a coating liquid has a smaller refractive index than the conductive coating film containing conductive fine particles, and the obtained transparent conductive film-coated substrate has excellent antireflection properties.

R _a Si (OR ') _4-a [1] (In the formula, R is a vinyl group, an aryl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom or a halogen atom, and R' vinyl group, an aryl group, an acrylic group, an alkyl group of carbon-based number _{1~8, -C 2 H 4 OC n} H 2n + 1 (n = 1
To 4) or a hydrogen atom, and a is an integer of 1 to 3. ) Such alkoxylanes include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraoctylsilane,
Examples thereof include methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, methyltriisopropoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane and dimethyldimethoxysilane.

When one or more of the above alkoxysilanes are hydrolyzed in the presence of an acid catalyst in, for example, a water-alcohol mixed solvent, a coating liquid for forming a transparent film containing a hydrolyzed polycondensate of alkoxysilane. Is obtained. The concentration of the film forming component contained in such a coating liquid is preferably 0.5 to 2.0% by weight in terms of oxide. The coating liquid for forming a transparent film used in the present invention has an average particle diameter of 5 to 300 nm, preferably 10 to 200 nm and a refractive index of 1.28 to 1.42, and further 1.28.
It is desirable to include low refractive index particles in the range of 1.40.

The average particle size of the low refractive index particles used is
It is appropriately selected according to the thickness of the transparent coating formed. If the low refractive index particles used have a refractive index of 1.42 or less, the resulting transparent conductive film-coated substrate has low bottom reflectance and luminous reflectance, and exhibits excellent antireflection performance. can do.

The amount of the low-refractive-index particles used is such that the content of the low-refractive-index particles in the transparent coating is 10 to 90% by weight, preferably 20 to 80% by weight, calculated as oxide. It is desirable to use. The low refractive index particles used in the present invention are not particularly limited as long as the average particle diameter and the refractive index are within the above ranges, and conventionally known particles can be used. For example, WO00 / 37359, a composite oxide sol disclosed in Japanese Patent Application Laid-Open No. 7-133105 filed by the applicant of the present application.
The porous composite oxide particles having the coating layer disclosed in Japanese Patent Laid-Open Publication can be preferably used.

Furthermore, in the coating liquid for forming the transparent coating used in the present invention, fine particles composed of a low refractive index material such as magnesium fluoride, a small amount so as not to impair the transparency and antireflection performance of the transparent coating. The conductive fine particles and / or an additive such as a dye or a pigment may be included. In the present invention, a coating film formed by applying such a coating liquid for forming a transparent film is dried at the time of drying or after drying.
Even if it is heated at 50 ° C or higher, or the uncured film is irradiated with electromagnetic waves such as ultraviolet rays, electron rays, X-rays, and γ rays having a wavelength shorter than visible light, or exposed to an atmosphere of active gas such as ammonia. Good. By doing so, the hardening of the film-forming component is accelerated, and the hardness of the obtained transparent film is increased.

Further, by applying a coating liquid for forming a transparent film,
When forming the coating, apply a transparent conductive coating at about 40-90 ° C.
Apply the coating solution for forming a transparent film while maintaining
When a treatment such as
Anti-glare transparent film with convexity and less glare
A coated substrate is obtained.Display device The substrate with a transparent conductive film according to the present invention, antistatic, electromagnetic
Approximately 10 required for shielding ²-10^FourSurface resistance in the range of Ω / □
And has excellent transparency and visible light range and
It has sufficient anti-reflection performance in the near infrared region,
It is preferably used as a face plate.

The display device according to the present invention comprises a cathode ray tube (C
RT), a fluorescent display tube (FIP), a plasma display (PDP), a liquid crystal display (LCD), and the like, which is an apparatus for electrically displaying an image, and is composed of the transparent conductive film-coated substrate as described above. It has a front plate.
When a conventional display device having a front plate is operated, an image is displayed on the front plate and at the same time the front plate is charged and electromagnetic waves are emitted from the front plate. Since the face plate is composed of the base material with the transparent conductive film having the surface resistance of approximately 10 ² to 10 ⁴ Ω / □, it is possible to prevent such charging and to prevent electromagnetic waves and the emission of the electromagnetic waves. The generated electromagnetic field can be effectively shielded.

Further, when reflected light is generated on the front plate of the display device, the reflected light makes it difficult to see the display image. However, in the display device according to the present invention, the front plate is sufficient in the visible light region and the near infrared region. Since the substrate is provided with a transparent conductive coating having antireflection performance, such reflected light can be effectively prevented. Furthermore, the front plate of the cathode ray tube is composed of the transparent conductive film-coated substrate according to the present invention,
When a small amount of a dye or a pigment is contained in at least one of the transparent conductive film and the transparent film formed on the transparent conductive film, these dyes or pigments have a wavelength of a specific wavelength. By absorbing light, the contrast of the display image projected from the cathode ray tube can be improved.

[0061]

The coating liquid for forming a transparent conductive film according to the present invention has a specific ratio of indium oxide-based fine particles and tin oxide-based fine particles that are uniformly mixed and dispersed, so that the viscosity is low and the pot life is improved. However, it is possible to provide a coating liquid for forming a transparent conductive film having a high yield of a transparent conductive film-coated substrate and excellent manufacturing reliability because defects in appearance such as streaks, unevenness, and light spots do not occur. it can. Further, in addition to indium oxide, a predetermined amount of tin oxide-based fine particles are uniformly mixed and dispersed in the coating solution, so that even if fine particle carbon black and / or titanium black is blended as a colorant, the pot life is improved. It is possible to provide a substrate with a transparent conductive coating without causing deterioration in appearance defects such as streaks, unevenness, and light spots even when such a coating liquid is used.

Further, it is possible to provide a substrate having a transparent conductive film, which is excellent in antistatic performance, electromagnetic shielding performance, transparency, antireflection performance and the like, and is also excellent in salt water resistance and oxidation resistance. Furthermore, when such a substrate with a transparent conductive film is used as a front plate of a display device, it is excellent in antistatic performance, electromagnetic shielding performance, appearance, contrast, antireflection performance, and salt water resistance and oxidation resistance. Therefore, a display device having excellent durability can be provided.

[0063]

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

[0064]

[Manufacturing Examples] a) Preparation of Fine Particle Dispersion Liquid Indium oxide fine particle (A) dispersion liquid, tin oxide fine particle (B) dispersion liquid, metal fine particle dispersion liquid, fine particle carbon used in this example and comparative example. The black dispersion was prepared as follows.

Sn-doped indium oxide (ITO) fine particles (P-
1) Preparation of dispersion solution A solution obtained by dissolving 79.9 g of indium nitrate in 686 g of water and 12.7 g of potassium stannate at a concentration of 10% by weight.
And a solution obtained by dissolving it in a potassium hydroxide solution of 1. were prepared, and these solutions were added to 1000 g of pure water kept at 50 ° C. over 2 hours. During this period, the pH of the system is set to 1
It was held at 1. The Sn-doped indium oxide hydrate is filtered from the obtained Sn-doped indium oxide hydrate dispersion.
After washing, disperse in water again to obtain a solid content of 10% by weight.
A metal oxide precursor hydroxide dispersion liquid of was prepared. This dispersion was spray dried at a temperature of 100 ° C. to prepare a metal oxide precursor hydroxide powder. The above powder was heat-treated at 550 ° C. for 2 hours in a nitrogen gas atmosphere.

This was dispersed in ethanol to a concentration of 30% by weight, the pH was adjusted to 3.5 with an aqueous nitric acid solution, and the mixed solution was pulverized for 0.5 hours in a sand mill while being kept at 30 ° C. Then, a sol was prepared. Then, ethanol was added to prepare a Sn-doped indium oxide fine particle (P-1) dispersion liquid having a concentration of 20% by weight. The average particle size of the obtained conductive metal oxide particles (P-1) was measured as follows, and the results are shown in the table.

SEM photographs of the conductive fine particles were taken, the particle diameters of 20 particles were measured, and the average value was shown in the table as the average particle diameter. Preparation of F.Sn -doped indium oxide fine particle (P-2) dispersion A solution obtained by dissolving 79.9 g of indium nitrate in 686 g of water and 2.7 g of tin fluoride in a potassium hydroxide solution having a concentration of 10% by weight. And a solution obtained by dissolving the solution were prepared, and these solutions were added to 1000 g of pure water kept at 50 ° C. over 2 hours. During this period, the system pH was maintained at 11. The F-doped indium oxide hydrate dispersion was filtered and washed from the obtained F-doped indium oxide hydrate dispersion, and then dispersed again in water to disperse the metal oxide precursor hydroxide with a solid content concentration of 10% by weight. A liquid was prepared. This dispersion is
Spray drying was carried out at a temperature of 100 ° C. to prepare a metal oxide precursor hydroxide powder. The above powder was placed under a nitrogen gas atmosphere at 55
Heat treatment was performed at 0 ° C. for 2 hours.

This was dispersed in ethanol to a concentration of 30% by weight, and the pH was adjusted to 3.5 with an aqueous nitric acid solution. The mixture was kept at 30 ° C. and ground with a sand mill for 0.5 hours. Then, a sol was prepared. Then, ethanol was added to prepare a dispersion of F.Sn-doped indium oxide fine particles (P-2) having a concentration of 20% by weight. The average particle size was measured.

The results are shown in Table 1. Preparation of Sb-doped tin oxide (ATO) fine particle (P-3) dispersion A solution was prepared by dissolving 57.7 g of tin chloride and 7.0 g of antimony chloride in 100 g of methanol. The prepared solution was added to 1000 g of pure water under stirring at 90 ° C. for 4 hours for hydrolysis, the generated precipitate was separated by filtration and washed, and then dispersed again in water to have a solid content concentration of 10% by weight. A metal oxide precursor hydroxide dispersion liquid of was prepared. This dispersion is
Spray drying was carried out at a temperature of 100 ° C. to prepare a metal oxide precursor hydroxide powder. The above powder was placed under a nitrogen gas atmosphere at 55
Heat treatment was performed at 0 ° C. for 2 hours. 30 g of this powder was added to 70 g of an aqueous potassium hydroxide solution (containing 3.0 g as KOH), and the mixed solution was pulverized with a sand mill for 3 hours while maintaining at 30 ° C. to prepare a sol. Then, this sol is treated with an ion exchange resin to dealkalize, and pure water is added to make the concentration 20.
A dispersion liquid of Sb-doped tin oxide fine particles (P-3) at a weight percentage was prepared. The average particle size was measured.

The results are shown in Table 1. Preparation of tin oxide fine particle (P-4) dispersion liquid A solution was prepared by dissolving 57.7 g of tin chloride in 100 g of methanol. The prepared solution was added to 1000 g of ammonia water having a concentration of 0.1% by weight under stirring at 90 ° C. for 4 hours for hydrolysis, the generated precipitate was separated by filtration and washed, and then dispersed again in water. Thus, a metal oxide precursor hydroxide dispersion liquid having a solid content concentration of 10% by weight was prepared. This dispersion is
Spray drying was carried out at a temperature of 100 ° C. to prepare a metal oxide precursor hydroxide powder. The above powder was placed under a nitrogen gas atmosphere at 55
Heat treatment was performed at 0 ° C. for 2 hours. 30 g of this powder was added to 70 g of an aqueous potassium hydroxide solution (containing 3.0 g as KOH), and the mixed solution was pulverized with a sand mill for 3 hours while maintaining at 30 ° C. to prepare a sol. Then, this sol is treated with an ion exchange resin to dealkalize, and pure water is added to make the concentration 20.
A dispersion liquid of tin oxide fine particles (P-4) at a weight percentage was prepared. The average particle size was measured.

The results are shown in Table 1. Preparation of dispersion of silver-palladium alloy fine particles (P-5) To 100 g of pure water, 0.01 parts by weight of 1 part by weight of alloy fine particles capable of obtaining trisodium citrate was added in advance, and the concentration was calculated in terms of metal. Is 10% by weight, and a silver nitrate and palladium nitrate aqueous solution is added so that the weight ratio of silver and palladium is 8: 2, and further an aqueous solution of ferrous sulfate is added in an amount equal to the total mole number of silver nitrate and palladium nitrate. Then, the mixture was stirred under a nitrogen atmosphere for 1 hour to obtain a dispersion liquid of silver-palladium alloy fine particles. The obtained dispersion liquid is washed with water by a centrifuge to remove impurities, and then dispersed in water to prepare a silver-palladium alloy fine particle having a concentration of 3% by weight (P
-5) Dispersion liquid was prepared. The average particle diameter of the silver-palladium alloy fine particles was 8 nm.

Carbon fine particles (P-6) As a colorant, carbon fine particles (manufactured by Mitsubishi Chemical Corporation: average particle diameter 60 nm) were dispersed in water to a concentration of 20% by weight to prepare a dispersion liquid. b) Preparation of matrix-forming component liquid (M) A mixed solution of 50 g of ethyl orthosilicate (SiO ₂ : 28% by weight), 194.6 g of ethanol, 1.4 g of concentrated nitric acid, and 34 g of pure water was stirred at room temperature for 5 hours to obtain SiO 2. A liquid (M) containing a matrix-forming component having a concentration of ₂ % by weight was prepared.

[0073]

[Table 1]

[0074]

Examples 1 to 8 and Comparative Examples 1 to 4 c) Transparent conductive film type
Preparation of Application Coating Liquids (C-1) to (C-12) First, the fine particle (P-1) to (P-6) dispersions obtained above were mixed at the compounding ratios shown in Table 2 ( A) The dispersion liquid and the tin oxide type fine particle (B) dispersion liquid are mixed and uniformly mixed using a mixer (Campe Co., Ltd .: Sand Mill), and the above matrix is formed therein to have the concentration shown in Table 2. Contains ingredients
The liquid (M) and a mixed solvent of water and butyl cellosolve 2: 2 are mixed to prepare a transparent conductive film-forming coating liquid (C-1) to (C-8),
And (C-10) were prepared.

The coating liquids (C-9), (C-11) and (C-12) are
It was prepared in the same manner except that it was not processed in the mixer. The viscosity of the dispersion liquid before and after the mixing treatment of the conductive fine particle dispersion liquid with a mixer was measured with a viscometer (TOKI Co., Ltd .: B-type viscometer). The results are shown in Table 2.

[0076]

[Table 2]

D) Preparation of Coating Liquid (B) for Forming Transparent Film The liquid ( M) containing the above matrix-forming components was mixed with ethanol / butanol / diacetone alcohol / isopropanol (2: 1: 1: 5 weight ratio). Add mixed solvent and add S
A coating liquid (B) for forming a transparent film having an iO ₂ concentration of 1% by weight was prepared. Manufacture of panel glass with transparent conductive coating The above coating solution for forming transparent conductive coating (C-1 under the conditions of 100 rpm and 90 seconds by spinner method while maintaining the surface of panel glass for cathode ray tubes (17 ") at 40 ° C. ) To (C-12) were applied and dried, and the thickness of the conductive layer was measured and the results are shown in Table 3.

Then, on the transparent conductive film thus formed, similarly, 100 rpm by a spinner method,
The coating liquid (B) for forming a transparent coating film was applied and dried under the condition of 90 seconds and baked at 160 ° C. for 30 minutes to obtain a substrate with a transparent conductive film. The thickness of the transparent coating at this time is 50 n
It was formed so as to be m. The surface resistance of these transparent conductive film-coated substrates is measured by a surface resistance meter (Mitsubishi Oil Chemical Co., Ltd .: LORESTA).
Measured with a haze computer (Nippon Denshoku
(Mfd .: 3000A). The reflectance is measured using a reflectometer (MCPD-2000 manufactured by Otsuka Electronics Co., Ltd.), and the wavelength is 400 to 7
The reflectance at the wavelength having the lowest reflectance in the range of 00 nm was determined as the bottom reflectance, and the average reflectance at the wavelength of 400 to 700 nm was determined as the luminous reflectance.

The results are shown in Table 3. For evaluation of manufacturing reliability, streaks and unevenness were observed by seeing through Schaucassen, and light spots were directly visually observed, evaluated according to the following criteria, and the results are shown in the table. Streak : No streak is observed when observed from the front side of the panel.

Δ: Observed from the front side of the panel, but not from the back side. X: It is also observed from the back surface of the panel. Unevenness : There is no unevenness in color due to uneven film thickness.

Δ: Color unevenness is slightly observed. X: Color unevenness is clearly recognized. Light spot ◯: Light spot zero with a diameter of 0.5 mm or more on the panel surface, 0.1 mm
Number less than 200 Less than △: Light spot on the panel surface with a diameter of 0.5 mm or more, 2 or less, 0.1
Number less than mm 200 to 249 x: Light spot with a diameter of 0.5 mm or more, 3 or more, 0.1 on the panel surface
A number of 250 or more less than mm, and as a reliability evaluation, a salt water resistance and an oxidation resistance test were conducted by the following methods.

[Salt water resistance] To a salt solution having a concentration of 5% by weight,
The transparent conductive film-coated substrate pieces obtained in the above Examples and Comparative Examples were dipped so as to be partially immersed in a saline solution, and 2
After leaving it for 4 hours and 48 hours, it was taken out, and the change in color tone with respect to the unimmersed part was observed. [Oxidation resistance] The transparent conductive film-coated substrate pieces obtained in the above Examples and Comparative Examples were immersed in an aqueous hydrogen peroxide solution having a concentration of 2% by weight so that a part thereof was immersed in the aqueous hydrogen peroxide solution. Two
After leaving it for 4 hours, it was taken out, and the change in color tone with respect to the unimmersed part was observed.

[0083]

[0084]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 183/02 C09D 183/02 5G323 183/04 183/04 185/00 185/00 H01B 1/22 H01B 1 / 22 Z 5/14 5/14 A 13/00 503 13/00 503B // G02F 1/1343 G02F 1/1343 (72) Inventor Toshiro Komatsu 13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka F-term in Wakamatsu Plant of Mocha Chemical Industries Co., Ltd. JA19 JA26 JA32 JA53 KA06 MA14 MA15 NA03 NA04 NA20 NA22 NA26 PB09 PB11 PC03 PC08 5G301 DA13 DA23 DA60 5G307 FA01 FA02 FB01 FC09 5G323 BA02 BB01 BB02 BC03

Claims (8)

[Claims] 1. A method for producing a coating liquid for forming a transparent conductive film, comprising indium oxide fine particles (A) and tin oxide fine particles (B) as conductive fine particles, and indium oxide fine particles (A). It is characterized in that the conductive oxide particles are uniformly mixed and dispersed in a polar solvent in a mixing ratio (A / B) with tin oxide particles (B) in the range of 98/2 to 60/40 (weight ratio). A method for producing a coating liquid for forming a transparent conductive film. 2. The viscosity of the dispersion when the conductive fine particles are dispersed in a polar solvent is uniformly mixed so as to be in the range of 1.0 to 5 cp when the concentration of the conductive fine particles is 20% by weight. The method for producing a coating liquid for forming a transparent conductive film according to claim 1, wherein the coating liquid is dispersed. 3. The indium oxide fine particles (A) have an average particle diameter of 2 to 200 nm, and the tin oxide fine particles (B) have an average particle diameter of 2 to 200 nm. Alternatively, the method for producing a coating liquid for forming a transparent conductive film according to item 2. 4. The indium oxide based fine particles (A) are indium oxide, indium oxide doped with Sn or F, and the tin oxide based fine particles (B) are tin oxide, Sb,
The method for producing a coating liquid for forming a transparent conductive film according to claim 1, wherein F or P is doped tin oxide. 5. The transparent conductive coating film forming method according to claim 1, wherein carbon black and / or titanium black is further dispersed as a colorant after the conductive fine particles are dispersed. Method for producing coating liquid. 6. A transparent conductive film-forming coating solution obtained by the method for producing a transparent conductive film-forming coating solution according to claim 1. 7. A substrate, a transparent conductive film containing the conductive fine particles on the substrate, and a transparent film provided on the transparent conductive film and having a refractive index lower than that of the transparent conductive film. A substrate having a transparent conductive coating formed by applying a transparent conductive coating-forming coating liquid produced by the method according to any one of claims 1 to 5 onto the surface of the substrate. A substrate with a transparent conductive film, which is formed. 8. A display device comprising a front plate composed of the substrate with a transparent conductive film according to claim 7, wherein the transparent conductive film is formed on the outer surface of the front plate. .