JP2001064540A - Coating liquid for forming transparent conductive film, substrate with transparent conductive film, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent, electrically conductive coated film-forming coating liquid which forms a transparent, electrically conductive coated film which has a low surface resistivity of from about 102 to 104 Ω/square, shows an excellent antistatic effect, anti-reflection effect and electromagnetic-screening property, has an excellent surface flatness/evenness, adhesion to substrates, chemical resistance, etc., and possessed an excellent appearance. SOLUTION: This transparent, electrically conductive coated film-forming coating liquid contains metal fine particle, a sulfur compound and a polar solvent. As the sulfur compound, at least one chosen from carbon disulfide, a mercapto group-containing organic compound, a mercapto group-containing silane compound and/or their hydrolytic polycondensates, is used. Preferably, the weight ratio of the sulfur compound to the metal fine particle in the coating liquid is from 0.005 to 0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating solution for forming a transparent conductive film, a substrate having a transparent conductive film using the coating solution for forming a transparent conductive film, and a display device provided with the base material.

[0002]

BACKGROUND OF THE INVENTION Conventionally, the surface of a transparent base material of a display panel such as a cathode ray tube, a fluorescent display tube, a liquid crystal display panel, etc.
For the purpose of preventing surface electrification and antireflection, formation of a transparent film having an antistatic function and an antireflection function has been performed. By the way, the effect of electromagnetic waves emitted from a cathode ray tube and the like on the human body has recently been considered a problem, and in addition to the conventional antistatic and antireflection, shields these electromagnetic waves and the electromagnetic field formed by the emission of the electromagnetic waves. It is desired to do.

As one of the methods for shielding such electromagnetic waves, there is a method of forming a conductive film for shielding electromagnetic waves on the surface of a display panel such as a cathode ray tube. However, if the conductive film is merely an antistatic conductive film, the surface resistance is at least 1
0 ⁷ Ω / □ as long as the surface resistance of the extent whereas is sufficient, the conductive coating for electromagnetic shielding 10 ² ~10 ⁴ Ω /
It was necessary to have a low surface resistance like □.

[0004] Such a conductive film having a low surface resistance is
When an attempt is made to use a coating solution containing a conductive oxide such as conventional Sb-doped tin oxide or Sn-doped indium oxide, the thickness must be greater than that of a conventional antistatic coating. The thickness of the conductive film is 10 to 20
Since the antireflection effect is not exhibited unless the thickness is about 0 nm, the antireflection effect is reduced when the film thickness is increased, so that a conductive oxide such as conventional Sb-doped tin oxide or Sn-doped indium oxide is used. The product has a problem that it is difficult to obtain a conductive film having low surface resistance, excellent electromagnetic wave blocking properties, and excellent antireflection.

[0005] As one method of forming a conductive film having a low surface resistance, a coating film containing metal fine particles is formed on the surface of a substrate using a conductive film forming coating solution containing fine metal particles such as Ag. Methods are also known. In this method, a colloidal metal fine particle dispersed in a polar solvent is used as a coating liquid for forming a metal fine particle-containing film. In such a coating liquid, in order to improve the dispersibility of the colloidal metal fine particle, The surface of the metal fine particles is surface-treated with an organic stabilizer such as polyvinyl alcohol, polyvinylpyrrolidone or gelatin.

However, in a conductive film formed using such a coating solution for forming a metal fine particle-containing film, the metal fine particles contact each other via a stabilizer in the film.
In some cases, the grain boundary resistance was large and the surface resistance of the coating did not decrease. 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. And the transparency and haze of the conductive film are reduced. Further, in the case of a cathode ray tube or the like, there is a problem that the tube is deteriorated when exposed to high temperatures.

In a conventional transparent conductive film containing fine metal particles such as Ag, the metal may be oxidized, particles may grow due to ionization, and in some cases, corrosion may occur. There is a problem that the light transmittance is reduced and the display device lacks reliability. In addition, JP 10
JP-A-204336 discloses that the stability of fine particles of metal such as silver is improved by coating the surface of the fine particles with a metal sulfur compound. However, when the surface of the metal fine particles is coated with these metal sulfur compounds, the conductivity of the film is not always satisfactory when a transparent conductive film is formed. Furthermore,
In such a conventionally used coating solution, the stability of the metal fine particles is insufficient, so that the coating film forming property decreases with time, and the flatness and uniformity of the coating film surface and the substrate. Adhesion and chemical resistance of the coating film were sometimes poor. In particular, when using a conventional coating solution, it is difficult to form a coating film having excellent appearance without streaky irregularities on the coating film surface,
That is, there is a problem that manufacturing reliability is poor.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has a low surface resistance of about 10 ² to 10 ⁴ Ω / □, and has antistatic properties, antireflection properties and electromagnetic shielding properties. Surface flatness / uniformity, adhesion to substrate,
It is an object of the present invention to provide a coating liquid for forming a transparent conductive film capable of forming a transparent conductive film having excellent chemical resistance and excellent appearance.

[0009]

SUMMARY OF THE INVENTION The coating solution for forming a transparent conductive film according to the present invention is characterized by containing fine metal particles, a sulfur compound and a polar solvent. The sulfur compound is preferably at least one sulfur compound selected from carbon disulfide, an organic compound having a mercapto group, a silane-based compound having a mercapto group, and / or a hydrolyzed condensation polymer thereof.

It is preferable that such a sulfur compound is contained so that the weight ratio of the sulfur compound to the metal fine particles (sulfur compound / metal fine particles) in the coating solution is 0.005 to 0.5. . The coating liquid for forming a transparent conductive film according to the present invention may contain an organic stabilizer, conductive fine particles other than the metal fine particles, and a matrix forming component.

A substrate with a transparent conductive film according to the present invention comprises: a substrate; a transparent conductive film formed by applying and drying the coating solution for forming a transparent conductive film on the surface of the substrate; The transparent conductive film is formed of a transparent film having a lower refractive index than the transparent conductive film formed on the surface of the transparent conductive film. The method for producing a material with a transparent conductive coating according to the present invention comprises applying the coating liquid for forming a transparent conductive coating described above on a substrate, drying the coating to form a transparent conductive coating, and then forming the transparent conductive coating. It is characterized in that a coating liquid for forming a transparent film is applied on the film to form a transparent film having a lower refractive index than the transparent conductive film.

Further, the display device according to the present invention includes a front plate composed of the substrate provided with the transparent conductive film manufactured by the above method, and the transparent conductive film is formed on the outer surface of the front plate. It is characterized by:

[0013]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described specifically. First, the coating liquid for forming a transparent conductive film according to the present invention will be described. The coating liquid for forming a transparent conductive film according to the present invention is characterized by containing a sulfur compound and a sulfur compound together with metal fine particles and a polar solvent. [Metal Fine Particles] Conventionally known metal fine particles can be used as the metal fine particles. Such metal fine particles may be composed of a single component metal or may contain two or more metal components. Is also good.

When two or more metal components are contained, the metal component may be an alloy in a solid solution state or a eutectic not in a solid solution, and the alloy and the eutectic coexist. You may. Since such composite metal fine particles suppress metal oxidation and ionization, particle growth and the like of the composite metal fine particles are suppressed, the corrosion resistance of the composite metal fine particles is high, and the conductivity and the decrease in light transmittance are small. It has excellent reliability.
Such metal fine particles include Au, Ag, Pd, Pt,
Rh, Ru, Cu, Fe, Ni, Co, Sn, Ti, In, Al,
Metal fine particles selected from metals such as Ta and Sb are exemplified. Further, as the composite metal fine particles, Au, Ag, Pd,
Pt, Rh, Ru, Cu, Fe, Ni, Co, Sn, Ti, In,
Composite metal fine particles composed of at least two or more metals selected from metals such as Al, Ta, and Sb are exemplified. Particularly preferred combinations of two or more metals are Au-Cu,
Ag-Pt, Ag-Pd, Au-Pd, Au-Rh, Pt-Pd, Pt-
Rh, Fe-Ni, Ni-Pd, Fe-Co, Cu-Co, Ru-Ag,
Au-Cu-Ag, Ag-Cu-Pt, Ag-Cu-Pd, Ag-Au-P
d, Au-Rh-Pd, Ag-Pt-Pd, Ag-Pt-Rh, Fe-Ni-
Pd, Fe-Co-Pd, Cu-Co-Pd and the like can be mentioned.

Au, Ag, Pd, Pt, Rh, Cu, C
When metal fine particles containing a metal such as o, Sn, In, and Ta are used, some of these metals may be in an oxidized state or may contain an oxide of the metal. Further, a P or B atom may be bonded to the metal. Such metal fine particles can be obtained, for example, by the following method described in JP-A-10-188681.

(I) A method of reducing one or more metal salts in a mixed solvent of alcohol and water. In this case, when two or more metal salts are used, the two or more metal salts may be reduced simultaneously or separately. In addition, you may add a reducing agent as needed. As the reducing agent, sulfuric acid
Iron, trisodium citrate, tartaric acid, sodium borohydride, sodium hypophosphite and the like. During the reaction, heat treatment may be performed at a temperature of about 100 ° C. or more in a pressure vessel. (ii) In a dispersion of single component metal fine particles or alloy fine particles,
A method in which fine particles or ions of a metal having a higher standard hydrogen electrode potential than the metal fine particles or alloy fine particles are present to precipitate a metal having a higher standard hydrogen electrode potential on the metal fine particles and / or alloy fine particles. A metal having a higher standard hydrogen electrode potential may be deposited on the composite metal fine particles thus obtained.

It is preferable that a large amount of metal having a high standard hydrogen electrode potential is present in the surface layer of the composite metal fine particles. As described above, when the metal having the highest standard hydrogen electrode potential is present in a large amount in the surface layer of the composite metal fine particles, oxidation and ionization of the composite metal fine particles are suppressed, and particle growth due to ion migration or the like can be suppressed. further,
Such composite metal fine particles have high corrosion resistance, so that a decrease in conductivity and light transmittance can be suppressed.

The average particle size of the metal fine particles used in the present invention is desirably in the range of 1 to 200 nm, preferably 2 to 70 nm. When the average particle diameter of the metal fine particles exceeds 200 nm, light absorption by the metal increases, and the light transmittance of the particle layer decreases and the haze increases. Therefore, when the coated substrate is used as a front plate of a cathode ray tube,
The resolution of the displayed image may decrease. Further, when the average particle diameter of the metal fine particles is less than 1 nm, the surface resistance of the particle layer rapidly increases, so that a film having a resistance value low enough to achieve the object of the present invention may not be obtained. is there.

[Sulfur compound] The sulfur compound used in the present invention is not particularly limited as long as it contains a sulfur atom.
S ₂ ), an organic compound having a mercapto group, a silane compound having a mercapto group, and / or one or more sulfur compounds selected from hydrolyzed polycondensates thereof are preferable.

Examples of the organic compound having a mercapto group include methanethiol (CH ₃ SH),

[0021]

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And the like. As the silane-based compound having a mercapto group, a compound represented by the following formula (1), a partial hydrolyzate of the compound, a hydrolyzate, or a condensation polymer of these hydrolysates can be used.

[0023]

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(Wherein 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 is a vinyl group, an aryl group, an acryl group, a carbon number of 1) 8 alkyl group, -C ₂ H ₄ OC _a H
_{2a + 1} (a = 1 to 4) or a hydrogen atom, n is an integer of 0 or more, and m is an integer of 0, 1, 2, or 3. Specifically, mercaptomethyldiethoxysilane (HS)
_{-Si (CH 3) (OC 2} H 5) 2), mercaptomethyltrimethoxysilane _{(HS-CH 2 -Si (OCH} 3) 3), mercaptomethyl trimethylsilane _{(HS-CH 2 -Si (CH} 3) ( OC
H ₃ ) ₂ ), 2-mercaptoethyl dimethoxyto (HS-C _{2
H 4 -Si (CH 3) (} OCH 3) 2), 3- mercaptopropyl methyldimethoxysilane _{(HS-C 3 H 6 -Si} (CH 3) 3), 3
- mercaptopropyl triethoxysilane (HS-C ₃ H _{6
-Si (OC 2 H 5) 3} ), 3- mercaptopropyltrimethoxysilane _{(HS-C 3 H 6 -Si} (OCH 3) 3) , and the like.

The above-mentioned sulfur compounds are contained in a coating solution.
A part may be adsorbed on the surface of the metal fine particles described above. The adsorption of the sulfur compound on the surface of the metal fine particles is performed, for example, as follows. Dissolve the sulfur compound in an organic solvent compatible with water,
This is added to an aqueous dispersion of fine metal particles.

The sulfur compound is dissolved in an organic solvent incompatible with water, and this solution is mixed with an aqueous dispersion of fine metal particles, and the mixture is shaken to distribute the fine metal particles to the organic solvent. A sulfur compound is added to the aqueous dispersion of the metal fine particles, an aggregate of the metal fine particles is formed with stirring, and the aggregate is separated by filtration and then dispersed again in an organic solvent. Since such a sulfur compound has a high adsorptivity to metal fine particles and is hard to be desorbed, the presence of the sulfur compound suppresses aggregation of the metal fine particles.
The metal fine particles can be stably dispersed in the coating solution. Such finely dispersed metal fine particles are stably dispersed even when the solvent is evaporated and concentrated at the time of drying after coating, so that drying unevenness does not occur at the time of drying. Since no streak-like unevenness is generated, a film having excellent flatness can be formed. Therefore, such a coating liquid is excellent in production stability.

In addition, a stabilizer has been added to the conventionally used coating liquid for forming a transparent conductive film in order to improve the stability of the metal fine particles. Since the molecular weight is low and does not contain sulfur, the adsorptivity to metal fine particles is weak, and the effect of improving the stability of metal fine particles is not sufficient. Thus, by causing (adsorbing) the sulfur compound,
Although the reason why the dispersion stability of the sulfur compound is improved is not clear, it is presumed that the zeta potential of the metal fine particle is reduced and the dispersion is stabilized by the adsorption of the sulfur compound to the metal fine particle. In addition, since the surface of the substrate is cleaned by the sulfur compound contained in the coating solution, the compatibility between the substrate surface and the coating solution is improved, and a flat film without unevenness can be formed. Inferred.

[Polar Solvent] The polar solvent used in the coating solution for forming a transparent conductive film in the present invention is water; methanol, ethanol, propanol, butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene Alcohols such as glycol, hexylene glycol, 1-ethoxy-2-propanol; esters such as methyl acetate, ethyl acetate; diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Ethers such as monomethyl ether and diethylene glycol monoethyl ether; keto such as acetone, methyl ethyl ketone, acetylacetone and acetoacetate Kind and the like. These may be used alone or as a mixture of two or more.

In the present invention, the coating liquid for forming a transparent conductive film used contains 0.01 to 5% by weight of metal fine particles,
Preferably, it is contained in an amount of 0.05 to 2% by weight. Further, it is desirable that the sulfur compound is contained so that the weight ratio of the sulfur compound to the metal fine particles in the coating solution is in the range of 0.005 to 0.5, preferably 0.01 to 0.2.

When the weight ratio is less than 0.01, the effect of improving the stability of the coating solution, the flatness of the coating surface, and the adhesion may not be obtained. On the other hand, when the weight ratio exceeds 0.5, the conductivity of the obtained film tends to decrease. The coating liquid for forming a transparent conductive film according to the present invention may contain conductive fine particles other than the metal fine particles.

As conductive fine particles other than metal fine particles,
Known transparent conductive inorganic oxide fine particles or fine particle carbon can be used. Examples of the transparent conductive inorganic oxide fine particles include tin oxide, tin oxide doped with Sb, F or P, indium oxide, indium oxide doped with Sn or F, antimony oxide, and lower titanium oxide. .

The average particle size of the conductive fine particles other than the metal fine particles is preferably in the range of 1 to 200 nm, and more preferably in the range of 2 to 150 nm. Such conductive fine particles,
It is sufficient that the metal fine particles are contained in an amount of 4 parts by weight or less per part by weight. When the amount of the conductive fine particles is more than 4 parts by weight, the conductivity is lowered and the electromagnetic wave shielding effect may be lowered, which is not preferable.

When such conductive fine particles are contained, a transparent conductive fine particle layer having more excellent transparency can be formed as compared with the case where the transparent conductive fine particle layer is formed only of metal fine particles. Further, by containing the conductive fine particles, a substrate with a transparent conductive film can be manufactured at low cost. The coating liquid for forming a transparent conductive film according to the present invention may contain a matrix-forming component that acts as a binder for the conductive fine particles after the film is formed. As such a matrix-forming component, those composed of one or more oxide precursors selected from silica, silica-based composite oxide, zirconia, and antimony oxide are preferable, and in particular, organosilicon such as alkoxysilane A hydrolyzed polycondensate of the compound or a silicic acid polycondensate obtained by dealkalization of an aqueous alkali metal silicate solution is preferably used. In addition, a resin for paint or the like can be used.

The matrix-forming component may be contained in an amount of 0.01 to 0.5 part by weight, preferably 0.03 to 0.3 part by weight, based on 1 part by weight of the metal fine particles. In the present invention, in order to improve the dispersibility of the metal fine particles,
An organic stabilizer may be contained in the coating liquid for forming a transparent conductive film. Specific examples of such organic stabilizers include gelatin, polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, and phthalic acid. Examples include polycarboxylic acids such as acids and citric acid and salts thereof, heterocyclic compounds, and mixtures thereof.

[0035] Such organic stabilizers can be used as metal fine particles 1
The amount may be 0.005 to 0.5 part by weight, preferably 0.01 to 0.2 part by weight, based on part by weight. When the amount of the organic stabilizer is less than 0.005 parts by weight, sufficient dispersibility cannot be obtained, and when the amount exceeds 0.5 parts by weight, conductivity may be inhibited. The coating liquid for forming a transparent conductive film according to the present invention is an alkali metal ion, an ammonium ion and a polyvalent metal ion present in the coating liquid, an inorganic anion such as a mineral acid, an organic anion such as acetic acid and formic acid, The total amount of the ion concentration released from the particles is desirably 10 mmol or less per 100 g of solids in the coating solution. In particular, an inorganic anion such as a mineral acid inhibits the stability and dispersibility of the metal fine particles, so that the lower the amount contained in the coating liquid, the more preferable. As the ion concentration decreases,
The dispersion state of the particulate components, particularly the conductive fine particles, contained in the coating liquid for forming a transparent conductive film is improved, and a coating liquid containing almost no aggregated particles can be obtained. The monodispersed state of the particulate components in the coating liquid is maintained during the formation of the transparent conductive fine particle layer. For this reason, when a transparent conductive film is formed from a coating solution for forming a transparent conductive film having a low ion concentration, no agglomerated particles are observed in the film.

In the transparent conductive film formed from the coating solution for forming a transparent conductive film having a low ion concentration as described above, since conductive fine particles such as metal fine particles are well dispersed and arranged, the transparent conductive film is transparent. As compared with the case where the conductive fine particles are aggregated in the conductive film, it is possible to form a transparent conductive film having the same conductivity with less conductive fine particles. Further, it is possible to form a transparent conductive fine particle layer having no point defects and uneven thickness, which is considered to be caused by aggregation of the granular components, on the base material.

The deionizing method for obtaining a coating solution having a low ion concentration as described above may be a method in which the ion concentration finally contained in the coating solution falls within the above range. Although there is no particular limitation on the method of deionization, a dispersion of the particulate component used as a raw material of the coating liquid, or a coating liquid prepared from the dispersion may be used as a cation exchange resin and / or an anion exchange resin. And a method of washing these liquids with an ultrafiltration membrane or the like.

Substrate with a Transparent Conductive Film The substrate with a transparent conductive film according to the present invention is formed by applying a substrate and the above-mentioned coating solution for forming a transparent conductive film to the surface of the substrate and drying the substrate. And a transparent film having a lower refractive index than the transparent conductive film formed on the surface of the transparent conductive film.

As the substrate used in the present invention, a film made of glass, plastic, ceramic or the like,
Substrates such as sheets or other molded articles are included. Examples of the metal fine particles include the same as those described above. The thickness of the transparent conductive film is preferably in the range of 3 to 200 nm, and more preferably in the range of 5 to 150 nm. If the thickness is in this range, a substrate with a transparent conductive film having an excellent electromagnetic shielding effect can be obtained. Can be.

In the substrate with a transparent conductive film according to the present invention,
A transparent film having a lower refractive index than the transparent conductive film is formed on the transparent conductive film. The thickness of the formed transparent film is 20 to 300 nm, preferably 40 to 2 nm.
It is preferably in the range of 00 nm. Such a transparent film is not particularly limited as long as the refractive index is lower than that of the transparent conductive film. For example, silica,
It is formed from inorganic oxides such as titania and zirconia, and composite oxides thereof. In the present invention, a silica-based coating composed of a hydrolyzed polycondensate of a hydrolyzable organosilicon compound or a silicic acid polycondensate obtained by dealkalization of an aqueous alkali metal silicate solution is particularly preferred as the transparent coating.

The substrate with a transparent conductive film having such a transparent film formed thereon is excellent in antireflection performance. In addition, the transparent coating may contain additives such as fine particles, dyes, and pigments made of a low refractive index material such as magnesium fluoride, if necessary. Such a substrate with a transparent conductive film according to the present invention, first, after applying the coating liquid for forming a transparent conductive film described above on the substrate, and dried to form a transparent conductive film, then The transparent conductive film is manufactured by applying a coating liquid for forming a transparent film on the transparent conductive film to form a transparent film having a lower refractive index than the transparent conductive film.

Examples of the method of applying the coating liquid for forming a transparent conductive film include a dipping method, a spinner method, a spray method, a roll coater method, and a flexographic printing method. After applying the coating solution for forming a functional film, the coating solution is dried at a temperature in a range from room temperature to about 90 ° C. When the matrix forming component as described above is contained in the coating liquid for forming a transparent conductive film, the matrix forming component may be cured.

The curing method includes the following methods. Heat curing The dried coating film is heated to cure the matrix component. The heat treatment temperature at this time is desirably 100 ° C. or higher, preferably 150 to 300 ° C. 100 ℃
If it is less than 30, the matrix forming component may not be cured sufficiently. Although the upper limit of the heat treatment temperature varies depending on the type of the base material, the upper limit may be lower than the transition point of the base material.

Electromagnetic Wave Curing After the coating step or the drying step, or during the drying step, the coating film is irradiated with an electromagnetic wave having a wavelength shorter than visible light to cure the matrix component. Ultraviolet rays, electron beams, X-rays, γ-rays, and the like are used as the electromagnetic waves to be applied to accelerate the curing of the matrix forming component, depending on the type of the matrix forming component. For example, to accelerate the curing of the UV-curable matrix-forming component, for example, the emission intensity is about 250 nm and 360 nm
And a high-pressure mercury lamp having a light intensity of 10 mW / m ² or more is used as an ultraviolet light source, and ultraviolet rays having an energy amount of 100 mJ / cm ² or more are irradiated.

Gas Curing After the coating or drying step or during the drying step, the matrix-forming component is cured by exposing the coating to a gas atmosphere that promotes the curing reaction of the matrix-forming component. Among the matrix-forming components, there is a matrix-forming component whose curing is promoted by an active gas such as ammonia, and a transparent conductive fine particle layer containing such a matrix-forming component is formed at a gas concentration of 100 to 100.
The treatment of the matrix-forming component can be greatly accelerated by performing the treatment for 1 to 60 minutes in a curing accelerating gas atmosphere having a concentration of 000 ppm, preferably 1,000 to 10,000 ppm.

In the present invention, a transparent film having a lower refractive index than that of the transparent conductive film formed as described above is formed. There is no particular limitation on the method for forming the transparent film, and depending on the material of the transparent film, a vacuum evaporation method, a sputtering method, a dry thin film forming method such as an ion plating method, or a dipping method, a spinner method, or the like described above. A wet thin film forming method such as a spray method, a roll coater method, and a flexographic printing method can be employed.

When the transparent film is formed by a wet thin film forming method, a conventionally known coating liquid for forming a transparent film can be used. Examples of such a coating liquid for forming a transparent film include:
Specifically, a coating liquid containing an inorganic oxide such as silica, titania, or zirconia, or a composite oxide thereof as a transparent film forming component is used. Among these, as a coating solution for forming a transparent film, a hydrolyzable polycondensate of a hydrolyzable organosilicon compound, or a silica-based transparent film for forming a silica-based transparent film containing a silicic acid solution obtained by dealkalizing an aqueous alkali metal silicate solution. The coating liquid is preferable, and particularly preferably contains a hydrolyzed polycondensate of an alkoxysilane represented by the following general formula [I]. The silica-based coating formed from such a coating solution has a smaller refractive index than the conductive fine particle layer containing the composite metal fine particles, and the resulting substrate with a transparent coating has excellent antireflection properties.

R _a Si (OR ′) _4-a [I] (wherein 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, 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. Examples of such alkoxylans include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraoctylsilane,
Examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, methyltriisopropoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, and the like.

When one or more of the above-mentioned alkoxysilanes are hydrolyzed, for example, in a water-alcohol mixed solvent in the presence of an acid catalyst, a coating liquid for forming a transparent film containing a hydrolyzed polycondensate of the alkoxysilane is obtained. Is obtained. The concentration of the film forming component contained in such a coating solution is preferably 0.5 to 2.0% by weight in terms of oxide. The coating solution for forming a transparent film used in the present invention is subjected to a deionization treatment in the same manner as in the case of the coating solution for forming a transparent conductive film, and the ionic concentration of the transparent conductive coating solution is changed to the value for forming the transparent conductive film. It may be reduced to the same level as the concentration in the application liquid.

Further, the coating liquid for forming a transparent film used in the present invention contains fine particles composed of a low refractive index material such as magnesium fluoride, and a small amount of the fine particles so as not to impair the transparency and antireflection performance of the transparent film. And / or additives such as dyes or pigments. In the present invention, a film formed by applying such a coating liquid for forming a transparent film is dried, or after drying, for 1 hour.
Heating at 50 ° C. or higher, irradiating an uncured coating with electromagnetic waves such as ultraviolet rays, electron beams, X-rays, and γ-rays having a wavelength shorter than that of visible light, or exposing it to an active gas atmosphere such as ammonia Good. By doing so, the curing of the film-forming component is promoted, and the hardness of the obtained transparent film is increased.

Further, when forming a film by applying a coating solution for forming a transparent film, the transparent conductive film is heated at about 40 to 90 ° C.
When the coating liquid for forming a transparent film is applied while being kept at the above, and the above-described treatment is performed, ring-like irregularities are formed on the surface of the transparent film, and a substrate with an antiglare transparent film having little glare is obtained. . Display device The substrate with a transparent conductive film according to the present invention is suitably used as a front plate of a display device.

The base material used for such a front plate has a surface resistance in the range of 10 ² to 10 ⁴ Ω / □ required for electromagnetic shielding, and is sufficient in the visible light region and the near infrared region. A substrate with a transparent conductive film having excellent antireflection performance is preferred. The display device according to the present invention includes a cathode ray tube (CRT),
Fluorescent display tube (FIP), plasma display (PD
P), a device for displaying an image electrically, such as a liquid crystal display (LCD), including a front plate made of a substrate with a transparent conductive film as described above.

When a display device having a conventional front panel is operated, an electromagnetic wave is emitted from the front panel at the same time as an image is displayed on the front panel, and this electromagnetic wave affects the human body of the observer. in the display device according to the front plate 10 ² -
Since it is composed of a substrate with a transparent conductive film having a surface resistance of 10 ⁴ Ω / □, it is possible to effectively shield such an electromagnetic wave and an electromagnetic field generated by emission of the electromagnetic wave.

When reflected light is generated on the front plate of the display device, the reflected light makes it difficult to see a displayed image. However, in the display device according to the present invention, the front plate has sufficient visibility in the visible light region and the near infrared region. Since it is composed of a substrate with a transparent conductive film having antireflection performance, such reflected light can be effectively prevented. Further, the front plate of the cathode ray tube is composed of a substrate with a transparent conductive film according to the present invention,
When at least one of the transparent conductive film and the transparent film formed on the transparent conductive film contains a small amount of dye or pigment, the dye or pigment absorbs light having a specific wavelength, The contrast of the display image broadcasted from the cathode ray tube can be improved.

Further, since the front plate of the cathode ray tube is formed from the coating liquid for forming a transparent conductive film containing the sulfur compound according to the present invention, it has no streak-like unevenness, good appearance, and a moire phenomenon. A clear display image can be obtained without generation of visible light and scattering of visible light.

[0056]

According to the present invention, it is possible to form a transparent conductive film which is excellent in conductivity and electromagnetic shielding properties, can control the light transmittance, has excellent appearance, and is excellent in manufacturing reliability. Thus, a coating solution for forming a functional film can be obtained. The coating liquid for forming a transparent conductive film according to the present invention contains a sulfur compound together with metal fine particles in the coating liquid, and the sulfur compound has a strong adsorptivity and is not easily desorbed. Since the dispersion stability of the fine particles is improved, and the aggregation of the metal fine particles during drying of the coating film is suppressed, the appearance is excellent without causing uneven drying and streaky irregularities on the coating film surface. It is possible to obtain a highly reliable substrate with a transparent conductive film, which has high production reliability, is excellent in conductivity and electromagnetic shielding properties, has a small decrease in light transmittance and the like, and has high reliability.

When such a substrate with a transparent conductive film is used as a front plate of a display device, a display device which is excellent in electromagnetic shielding properties and antireflection properties and which can display a clear image because there is no appearance defect is provided. Obtainable.

[0058]

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

[0059]

Examples 1 to 9 and Comparative Example 1 a) Dispersion of conductive fine particles
Preparation Table 1 shows the compositions of the dispersions of metal fine particles used in the present examples and comparative examples. Dispersions of metal fine particles (P-1 to P-4) were prepared by the following method. To 100 g of pure water, trisodium citrate was added in advance so as to be 0.01 part by weight per 1 part by weight of metal fine particles, and the concentration became 10% by weight in terms of metal.
An aqueous solution of silver nitrate and palladium nitrate was added so that the metal species had the weight ratio shown in Table 1, and an aqueous solution of ferrous sulfate having the same mole number as the total mole number of silver nitrate and palladium nitrate was added. The mixture was stirred to obtain a dispersion of metal fine particles. The obtained dispersion is washed with a centrifuge to remove impurities, and then dispersed in water. Then, a sulfur compound solution in which the sulfur compound shown in Table 1 is dissolved in the solvent shown in Table 1 is mixed. Water was removed with a rotary evaporator and the mixture was concentrated to prepare metal fine particle dispersions (S-1 to S-4) having solid contents shown in Table 1. Further, a metal fine particle dispersion (S-9) was prepared in the same manner as the metal fine particle dispersion (S-1), except that the solvent was used without using a sulfur compound in the metal fine particle dispersion (S-1). .

A dispersion of metal fine particles (P-5 to P-8) was prepared by the following method. To 100 g of pure water, trisodium citrate was added in advance in an amount of 0.1 part by weight per 1 part by weight of metal fine particles, and the concentration was 1% by weight in terms of metal.
And chloroauric acid so that the metal species has the weight ratio shown in Table 1,
An aqueous solution of palladium chloride and ruthenium chloride was added and dissolved, and an aqueous solution of sodium borohydride having a concentration of 5% by weight in equimolar number with the total number of moles of the dissolved metal salts was added to obtain a dispersion of fine metal particles. The dispersion was washed on an ultrafiltration device and concentrated. Thereafter, a sulfur compound solution obtained by dissolving the sulfur compound shown in Table 1 in the solvent shown in Table 1 was mixed, and then water was removed and concentrated by a rotary evaporator to disperse metal fine particles having a solid content concentration shown in Table 1. Liquids (S-5 to S-8) were prepared.

A dispersion of conductive carbon fine particles (P-9) was prepared by the following method. To 100 g of 1-ethoxy-2-propanol, conductive carbon fine particles (P-9) (manufactured by Mitsubishi Chemical Corporation, average particle diameter: 60 nm) were added to a concentration shown in Table 1, and a conductive carbon fine particle dispersion (S -10) was prepared. Table 1 shows the composition of the prepared fine particle dispersion.

[0062]

[Table 1]

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 added at room temperature for 5 hours. By stirring, a liquid (M) containing a matrix-forming component having an SiO ₂ concentration of 5% by weight was prepared. c) Preparation of a coating solution for forming a transparent conductive film A dispersion of (S-1) to (S-10) shown in Table 1, a solution (M) containing the above matrix-forming component, ethanol, isopropyl alcohol, t- From butanol and 1-ethoxy-2-propanol, coating liquids (CS-1) to (C
(S-8) and (CS-10) were prepared. Further, in the case of using the dispersion of (S-9), C ₁₂ H ₂₅ SH was added as a sulfur compound so that the concentration in the coating solution was 500 ppm by weight, and the coating solution for forming a transparent conductive film ( CS-9) was prepared.

Table 2 shows the compositions of the prepared coating solutions.

[0065]

[Table 2]

D) Preparation of the Coating Solution (B) for Forming a Transparent Film The (M) solution containing the matrix-forming component was mixed with ethanol / butanol / diacetone alcohol / isopropyl alcohol (2: 1: 1: 5 weight ratio). Was added to prepare a coating solution (B) for forming a transparent film having a SiO ₂ concentration of 1% by weight.

[0067]

Examples 10 to 18 and Comparative Example 2 Panel with transparent conductive film
While the surface of the CRT panel glass (14 ″) is kept at 40 ° C., the above-mentioned coating liquids for forming a transparent conductive film (CS-1) to (CS-10) are spinnered at 100 rpm for 90 seconds. ) Was applied so that the film thickness of each transparent conductive film became 20 nm, and dried.

Next, on the transparent conductive fine particle layer thus formed, a 100 rp
The coating liquid (B) for forming a transparent film is applied and dried under the conditions of m and 90 seconds so that the film thickness of the transparent film becomes 80 nm, and baked at 160 ° C. for 30 minutes to obtain a substrate with a transparent conductive film. Was. The surface resistance of these substrates with a transparent conductive film was measured with a surface resistance meter (LORESTA, manufactured by Mitsubishi Yuka Co., Ltd.), and the haze was measured with a haze computer (3000A, manufactured by Nippon Denshoku Co., Ltd.). . The reflectance was measured using a reflectometer (MCPD-2000, manufactured by Otsuka Electronics Co., Ltd.), and the reflectance at the wavelength having the lowest reflectance in the wavelength range of 400 to 700 nm was displayed. The particle size of the fine particles is
A Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.) was used.

Observation of external appearance: Evaluation criteria ◎: No streak-like unevenness is observed at all ○: Streak-like unevenness is slightly observed △: Streak-like unevenness is clearly observed Manufacturing reliability: 9 more panel glass with transparent conductive coating
Each sheet was prepared and evaluated in the same manner as above.

Evaluation criteria: Number of those evaluated as 中 out of a total of 10 sheets The results are shown in Table 3.

[0071]

[Table 3]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 1/10 H05K 9/00 V H01B 5/14 G02B 1/10 A H05K 9/00 Z F term (Reference) ) 2K009 AA02 CC02 CC03 CC06 CC09 CC14 CC42 DD02 DD05 EE03 4F100 AA20A AB01A AB19A AB22A AH04A AK52A AR00A AR00B AT00C BA03 BA07 BA10B BA10C DE01A EH462 EJ862 JD08 JG01A JN1HA01A18A12J18A HA14 NA01 NA19 NA20 PA17 PA19 PA21 PB09 PC03 PC08 5E321 BB23 GG05 GH01 5G307 FA01 FA02 FB01 FB02 FC05 FC08 FC10

Claims (10)

[Claims] 1. A coating solution for forming a transparent conductive film, comprising metal fine particles, a sulfur compound and a polar solvent. 2. The sulfur compound is at least one sulfur compound selected from carbon disulfide, an organic compound having a mercapto group, a silane compound having a mercapto group, and / or a hydrolyzed condensation polymer thereof. The coating liquid for forming a transparent conductive film according to claim 1, wherein: 3. The weight ratio of the sulfur compound to the metal fine particles (sulfur compound / metal fine particles) in the coating solution is 0.005 to 0.5.
The coating liquid for forming a transparent conductive film according to claim 1 or 2, wherein the coating liquid is 5. 4. The coating liquid for forming a transparent conductive film according to claim 1, further comprising an organic stabilizer. 5. The coating liquid for forming a transparent conductive film according to claim 1, further comprising conductive fine particles other than said metal fine particles. 6. The transparent electroconductive film-forming coating solution contains a matrix-forming component.
5. The coating liquid for forming a transparent conductive film according to any one of 5. 7. The method according to claim 1, wherein said matrix-forming component comprises one or more oxides selected from silica, silica-based composite oxide, zirconia, and antimony oxide. The coating liquid for forming a transparent conductive film according to the above. 8. A substrate, a transparent conductive film formed by applying and drying the coating liquid for forming a transparent conductive film according to claim 1 on the surface of the substrate, A substrate with a transparent conductive film comprising a transparent film having a lower refractive index than the transparent conductive film formed on the surface of the conductive film. 9. A transparent conductive film-forming coating solution according to any one of claims 1 to 7, which is applied to a substrate and dried to form a transparent conductive film. A method for producing a substrate with a transparent conductive film, comprising applying a coating liquid for forming a transparent conductive film thereon to form a transparent film having a lower refractive index than the transparent conductive film. 10. A front plate comprising the substrate with a transparent conductive film according to claim 8, wherein a transparent conductive film is formed on an outer surface of the front plate. Display device.