WO2010095546A1

WO2010095546A1 - Transparent conductive film and transparent electrode

Info

Publication number: WO2010095546A1
Application number: PCT/JP2010/051942
Authority: WO
Inventors: 博和小山; 宏高田
Original assignee: コニカミノルタホールディングス株式会社
Priority date: 2009-02-17
Filing date: 2010-02-10
Publication date: 2010-08-26

Abstract

Disclosed is a transparent conductive film having both high conductivity and good transparency, wherein the entire surface is conductive. Also disclosed is a transparent electrode. The transparent conductive film is characterized by comprising, on a transparent base, a transparent conductive metal oxide layer that contains a metal nanowire.

Description

Transparent conductive film and transparent electrode

The present invention can be suitably used for a liquid crystal display element, an organic light emitting element, an inorganic electroluminescent element, a solar cell, an electromagnetic wave shield, a touch panel, electronic paper, etc., and has a high conductivity and a good transparency. The present invention relates to a film and a transparent electrode.

Transparent conductive films are used for liquid crystal displays, electroluminescence displays, plasma displays, electrochromic displays, solar cells, touch panels, transparent electrodes such as electronic paper, and electromagnetic shielding materials.

In general, for example, a metal oxide is used as the transparent conductive material. Specifically, indium oxide doped with tin or zinc (ITO, IZO), zinc oxide doped with aluminum or gallium (AZO, GZO), Examples thereof include tin oxide (FTO, ATO) doped with fluorine or antimony. In general, the metal oxide transparent conductive film is produced by a vapor deposition method such as a vacuum deposition method, a sputtering method, or an ion plating method. However, since these film forming methods require a vacuum environment, the apparatus is large and complicated, and since a large amount of energy is consumed for film forming, it is necessary to develop a technology that can reduce the manufacturing cost and environmental load. It was. On the other hand, as represented by a liquid crystal display and a touch display, an increase in the area of the transparent conductive material is aimed at, and accordingly, demands for weight reduction and flexibility of the transparent conductive material have increased. Furthermore, since the influence of the voltage drop of a transparent electrode becomes large in a large-area transparent electrode, further reduction in resistance has been demanded.

On the other hand, it has been reported that nanowires of metal elements having a bulk conductivity of 1 × 10 ⁷ S / m or more can be produced by various methods such as a liquid phase method and a gas phase method. For example, Non-Patent Document 1 can be referred to as a method for producing Ag nanowires. Furthermore, as a transparent conductive material technique specifically used for a low-resistance high-transparent conductive film, a method using metal nanowires as a conductor has been proposed (see Patent Document 1). However, in metal nanowires, when the diameter is reduced, the transparency is improved, but there is a contradictory problem that the conductivity is lowered, so it is difficult to ensure transparency while maintaining high conductivity. There is.

Patent Document 1 also describes the use of a transparent conductive resin as a binder resin, but the effect of solving these problems is small with a transparent conductive resin, and by including metal nanowires in the transparent conductive metal oxide layer. The present invention that solves these problems does not give any suggestion of a solution.

Patent Document 2 describes a light-emitting device using a transparent electrode formed of a metal and a transparent conductive polymer. This technology is a technology for arranging metal particles in a transparent conductive polymer. The present invention is different from the present invention in which metal nanowires are dispersed and contained in a transparent conductive metal oxide layer, and the present invention is to solve the problem by reducing the diameter of metal nanowires. There is no suggestion about reducing the problems inherent to metal nanowires.

US2007 / 0074316A1 Specification JP 2008-130449 A

An object of the present invention is to provide a transparent conductive film and a transparent electrode having a conductive surface as a whole and having both high conductivity and good transparency.

The above object of the present invention can be achieved by the following configuration.

1. A transparent conductive film comprising a transparent conductive metal oxide layer containing metal nanowires on a transparent substrate.

2. 2. The transparent conductive film according to 1 above, wherein the resistivity of the transparent conductive metal oxide layer excluding metal nanowires is 1 × 10 ⁵ Ωcm or less.

3. 3. The transparent conductive film as described in 1 or 2 above, wherein an average primary particle diameter of the transparent conductive metal oxide contained in the transparent conductive metal oxide layer is 50 nm or less.

4. 4. The transparent conductive film as described in 3 above, wherein the transparent conductive metal oxide is formed from a transparent conductive metal oxide sol.

5. 5. The transparent conductive film according to any one of 1 to 4, wherein the metal nanowire has an average diameter of 100 nm or less.

6. 6. A transparent electrode using the transparent conductive film described in any one of 1 to 5 above.

According to the present invention, it is possible to provide a transparent conductive film and a transparent electrode having the entire surface conductive and having both high conductivity and good transparency.

It is a schematic diagram which shows the dispersion state of the metal nanowire in the transparent conductive metal oxide layer which concerns on this invention.

Generally, when the diameter of the metal nanowire is reduced, the transparency is improved, but the conductivity is lowered.

As a result of intensive studies, the inventors of the present invention can suppress the decrease in conductivity even when the diameter of the metal nanowire is reduced by including the metal nanowire in the transparent conductive metal oxide layer. And found to be compatible with conductivity.

Although the reason why it is possible to suppress the decrease in conductivity even if the diameter of the metal nanowire is reduced is not well understood, I think that the following two effects are synergistic.

First, since the mean free path of electrons in the metal is several tens of nm, when the diameter of the metal nanowire becomes smaller than 100 nm, the conductivity is greatly reduced by scattering on the wire surface, but the transparent conductivity In a layer using a metal oxide, it is considered that scattering on the surface of the metal nanowire can be reduced to some extent, and conductivity is improved.

The other is that when the diameter is reduced, the number of wires increases and the number of wire contacts increases with the same weight per unit area. As a result, the contact resistance between the metal nanowires increases and the conductivity decreases. At this time, by dispersing the metal nanowires in the transparent conductive metal oxide layer, electricity can be passed between the metal nanowires through the transparent conductive metal oxide, thereby reducing the influence of the contact resistance between the metal nanowires and improving the conductivity. I think that I will do it. Here, the basis weight is the mass per unit area of the material (wire) constituting the transparent conductive film.

Hereinafter, the present invention, its components, and the best mode for carrying out the present invention will be described in detail.

[Metal nanowires]
In the transparent conductive material of the present invention, the metal nanowire functions as a main conductor. In the present invention, an element having a bulk conductivity of 1 × 10 ⁶ S / m or more can be used as the metal element of the metal nanowire. Specific examples of metal elements of the metal nanowire that can be preferably used in the present invention include Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Fe, Pd, Pt, Sn, Ti, and the like. Can be mentioned. In the present invention, two or more kinds of metal nanowires can be used in combination, but from the viewpoint of conductivity, it is preferable to use at least an element selected from Ag, Cu, Au, Al, and Co.

In the present invention, there are no particular limitations on the means for producing the metal nanowire, and for example, known means such as a liquid phase method and a gas phase method can be used. Moreover, there is no restriction | limiting in particular in a specific manufacturing method, A well-known manufacturing method can be used. For example, as a method for producing Ag nanowires, Adv. Mater. , 2002, 14, 833-837; Chem. Mater. 2002, 14, 4736-4745, etc., as a method for producing Co nanowires, such as JP 2006-233252, etc. as a method for producing Au nanowires, and JP 2002-266007, etc., as a method for producing Cu nanowires. Reference can be made to Japanese Unexamined Patent Publication No. 2004-149871. In particular, Adv. Mater. And Chem. Mater. The method for producing Ag nanowires reported in 1 can produce silver nanowires easily and in large quantities in an aqueous system, and the conductivity of silver is the largest among metals, so that the production of metal nanowires according to the present invention is possible. It can be preferably applied as a method.

In the present invention, the diameter of the metal nanowire is preferably 200 nm or less from the viewpoint of transparency. In particular, it is more effective that the effect of the present invention is 100 nm or less where the transparency is improved but the decrease in conductivity is large. More preferably, it is most preferably 70 nm or less. Here, the diameter of the metal nanowire is an average diameter, and for example, an electron micrograph can be taken for a sufficient number of nanowires using SEM or TEM, and can be obtained from the arithmetic average of the measured values of individual nanowire images. . The number of nanowires to be measured is at least 100 or more. When the diameter of the metal nanowire is reduced to a region of 100 nm or less, the conductivity is greatly reduced. In the present invention, the conductivity is lowered by dispersing the metal nanowire in the transparent conductive metal oxide layer. It can be suppressed to some extent. Even so, if the particle size is extremely small, the conductive deterioration is too large, so that it is preferably 10 nm or more, and more preferably 30 nm or more.

The diameter of the metal nanowire is, for example, the above-mentioned Adv. Mater. And Chem. Mater. In the case of the silver nanowire reported in (1), for example, it can be controlled by the molecular weight of the added PVP, and the diameter of the wire can be made thinner as the molecular weight is higher.

In the present invention, the average length of the metal nanowire is preferably 1 μm or more from the viewpoint of conductivity, and is preferably 100 μm or less from the viewpoint of the effect on the transparency due to aggregation. More preferably, it is 1 to 50 μm, and further preferably 3 to 50 μm.

[Transparent conductive metal oxide]
Examples of the transparent conductive metal oxide used in the present invention include ZrO ₂ , CeO ₂ , ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ and V _2. Examples thereof include metal oxides such as O ₅ , composite oxides thereof and composite metal oxides doped with different atoms, and in particular, indium oxide doped with tin or zinc (ITO) from the viewpoint of conductivity and transparency. , IZO), zinc oxide doped with aluminum or gallium (AZO, GZO), tin oxide doped with fluorine or antimony (FTO, ATO), or the like can be preferably used.

Such a material may be formed by a sputtering method using a vacuum process or the like, but is preferably formed by a wet process that does not use a vacuum process that can simplify manufacturing equipment. As a method using a wet process, a method of applying and drying a coating liquid containing a transparent conductive metal oxide, a so-called sol-gel method formed from a transparent conductive metal oxide of a metal alkoxide and a metal salt, Alternatively, a spray pyrolysis method or the like can be used. Among these, a method of applying and drying a coating liquid containing a transparent conductive metal oxide that exhibits conductivity without performing high-temperature heat treatment can be preferably used.

As coating methods, roll coating method, bar coating method, dip coating method, spin coating method, casting method, die coating method, blade coating method, bar coating method, gravure coating method, curtain coating method, spray coating method, doctor coating method Etc. can be used. As the printing method, known methods such as letterpress (letter plate) printing, stencil (screen) printing, lithographic (offset) printing, intaglio (gravure) printing, spray printing, and inkjet printing can be used.

When such a transparent conductive metal oxide is used, the average primary particle size is preferably 50 nm or less. Among them, a method using a metal oxide sol in which ultrafine particles of several nm or less are colloidally dispersed can be preferably used.

As the transparent conductive metal oxide having an average primary particle size of 50 nm or less, known materials can be used. For example, commercially available materials include SN-100P and SN-100D manufactured by Ishihara Sangyo Co., Ltd. -1, EI, etc. can be used.

The metal oxide sol can be produced by a known method. For example, for the SnO ₂ sol, the method described in Japanese Patent Publication No. 35-6616 can be used.

The above metal oxide sol is commercially available from Taki Chemical Co., Ltd., and such metal oxide sol can also be used.

It should be noted that the transparent conductive metal oxide having an average primary particle diameter exceeding 50 nm is insufficient in contact with the metal nanowire, and the effect of the present invention is hardly obtained.

These transparent conductive materials may be used alone or in combination of two or more. Furthermore, it may be used in combination with other resin components as long as the conductivity is not impaired, or may be used in combination with a conductive polymer. In particular, it is preferable to use it together with an energy curable resin because patterning becomes easy.

In order to obtain the effects of the present invention, the transparent conductive metal oxide layer according to the present invention preferably has a resistivity of 1 × 10 ⁵ Ωcm or less excluding metal nanowires, and a higher effect is obtained 1 ×. More preferably, it is 10 ³ Ωcm or less. It should be ^{noted that the} resistivity is preferably 1 × 10 ⁻⁵ Ωcm or more because the transmittance decreases when the resistivity becomes a metal region.

The resistivity excluding the metal nanowire of the transparent conductive metal oxide layer can be measured by a known method. For example, the metal nanowire of the transparent conductive metal oxide layer is formed on a smooth substrate such as glass or PET film. It can be obtained by forming a uniform film by itself except for the material, measuring the sheet resistance by a four-probe method, and taking the product of the sheet resistance value and the film thickness.

In the present invention, in order to effectively pass a current through the metal nanowire path, the metal nanowires in the transparent conductive metal oxide layer are uniformly dispersed, and at least a part of the individual wires overlap to form a random network. Preferably it is.

The method for uniformly dispersing the metal nanowires in the transparent conductive metal oxide layer is not particularly limited. For example, a dispersion of metal nanowires is applied onto a transfer substrate or directly onto a transparent substrate. A method of drying and forming a film in which metal nanowires are randomly arranged in a network, and applying and drying a coating liquid containing a transparent conductive metal oxide on the film, or a dispersion of metal nanowires and a transparent conductive metal oxide A method of mixing the coating liquid and applying and drying it directly on the substrate for transfer or directly on the transparent substrate is preferable.

Further, in order to arrange in a mesh shape in this way, the amount of metal nanowires varies depending on the material and shape of the wire, but when silver nanowires are used, it is preferably about 10 mg / m ² or more. Moreover, it is preferable that it is 500 mg / m < ² > or less from the point of transparency.

FIG. 1 shows a dispersion state of metal nanowires in a transparent conductive metal oxide layer according to the present invention. In FIG. 1, 1 is a metal nanowire, 2 is a transparent conductive metal oxide layer, 3 is a transparent adhesive resin, and 4 is a transparent substrate. In the present invention, the metal nanowires are dispersed in the transparent conductive metal oxide layer and may be regularly dispersed. For example, the metal nanowires may be randomly dispersed as shown in FIG. Good. Further, a part of the metal nanowire may be embedded in the transparent conductive metal oxide layer as shown in FIG. 1A, or all the metal nanowires may be transparent conductive metal oxide as shown in FIG. It may be buried in the material layer.

The transparent conductive film of the present invention preferably has a total light transmittance of 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

The total light transmittance can be measured according to a known method using a spectrophotometer or the like. The electrical resistance value of the transparent conductive film of the present invention is preferably 100 Ω / □ or less, more preferably 50 Ω / □ or less, and particularly preferably 10 Ω / □ or less as the surface resistivity. preferable. If it exceeds 100Ω / □, the surface uniformity of light emission may be inferior in an organic EL element having a wide light emission area. The surface resistivity can be measured in accordance with, for example, JIS K 7194: 1994 (resistivity testing method using a conductive plastic four-probe method) or the like, and can be easily performed using a commercially available surface resistivity meter. Can be measured.

There is no restriction | limiting in particular in the thickness of the transparent conductive film of this invention, Although it can select suitably according to the objective, Generally it is preferable that it is 10 micrometers or less, and transparency and a softness | flexibility improve, so that thickness becomes thin. Therefore, it is more preferable.

(Transparent substrate)
The transparent substrate used in the transparent conductive film of the present invention is not particularly limited as long as it has high light transmittance. For example, a glass substrate, a resin substrate, a resin film, and the like are preferable in terms of excellent hardness as a base material and ease of formation of a conductive layer on the surface. From the viewpoint, it is preferable to use a transparent resin film.

The transparent resin film that can be preferably used as the transparent substrate in the present invention is not particularly limited, and the material, shape, structure, thickness and the like can be appropriately selected from known ones. For example, polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate, modified polyester, polyethylene (PE) resin films, polypropylene (PP) resin films, polystyrene resin films, polyolefin resin films such as cyclic olefin resins, Vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, polyamide resin Examples include films, polyimide resin films, acrylic resin films, triacetyl cellulose (TAC) resin films, and the like, but wavelengths in the visible range (380 to 78). If the resin film transmittance of 80% or more in nm), can be preferably applied to a transparent resin film according to the present invention. Among these, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

The transparent substrate used in the present invention can be subjected to a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesion of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. For example, the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion. In addition, a barrier coat layer may be formed in advance on the transparent substrate, or a functional layer such as a hard coat layer or an antireflection layer may be formed in advance on the side opposite to the conductive layer. .

[Transparent electrode]
The transparent conductive film of the present invention allows a current to flow without a voltage drop even at a relatively long distance by passing through a path of a metal nanowire having a low resistance. Since it is a very short distance through, current can flow without voltage drop. As a result, electricity can flow through the entire surface without voltage drop even in a large area, and it works effectively as a transparent electrode.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
[Preparation of transparent conductive film TC-1]
A biaxially stretched PET film was used as the transparent substrate. After the corona discharge treatment was applied to the surface of the PET film, the following silver nanowire dispersion W-1 was applied and dried using a wire bar so that the basis weight of the silver nanowire was 80 mg / m ^2. The film which has is produced.

Next, the film is cut into 3 cm × 3 cm, and the following fine particle ATO-containing liquid B-1 is overcoated and dried using a spin coater, to form a transparent conductive metal oxide layer having a dry film thickness of 500 nm. Thus, a transparent conductive film TC-1 was produced.

(Preparation of silver nanowire dispersion W-1)
In this example, silver nanowires were used as metal nanowires. Silver nanowires are described in Adv. Mater. , 2002, 14, 833 to 837, silver nanowires having an average diameter of 75 nm and an average length of 35 μm are prepared using PVP having a molecular weight of 50,000, and silver nanowires are formed using an ultrafiltration membrane. After being filtered and washed with water, it was redispersed in ethanol to prepare a silver nanowire dispersion W-1 (silver nanowire content 5 mass%).

<Fine particle ATO-containing liquid B-1>
Sb-doped SnO ₂ fine particles (SN100D manufactured by Ishihara Sangyo Co., Ltd., solid content 30%) 16 g
Compound (UL-1) 0.02g
Modified aqueous polyester A (solid content 18%) 3g
Finish to 100 ml with water.

(Synthesis of modified aqueous polyester A)
In a polycondensation reaction vessel, 35.4 parts of dimethyl terephthalate, 33.63 parts of dimethyl isophthalate, 17.92 parts of 5-sulfo-isophthalic acid dimethyl sodium salt, 62 parts of ethylene glycol, 0.065 calcium acetate monohydrate And 0.022 parts of manganese acetate tetrahydrate were added and subjected to a transesterification reaction while distilling off methanol at 170 to 220 ° C. in a nitrogen stream, and then 0.04 part of trimethyl phosphate, a polycondensation catalyst. Then, 0.04 parts of antimony trioxide and 6.8 parts of 1,4-cyclohexanedicarboxylic acid were added, and the esterification was carried out by distilling off a theoretical amount of water at a reaction temperature of 220 to 235 ° C. Thereafter, the reaction system was further depressurized and heated for about 1 hour, and finally subjected to polycondensation at 280 ° C. and 133 Pa or less for about 1 hour to obtain a modified aqueous polyester A precursor. The intrinsic viscosity of the precursor was 0.33.

850 ml of pure water was put into a 2 L three-necked flask equipped with a stirring blade, a reflux condenser, and a thermometer, and 150 g of the above precursor was gradually added while rotating the stirring blade. After stirring for 30 minutes at room temperature, the mixture was heated to an internal temperature of 98 ° C. over 1.5 hours, and heated and dissolved at this temperature for 3 hours. After completion of the heating, the mixture was cooled to room temperature over 1 hour and left overnight to prepare a solution having a solid content concentration of 15% by mass.

1900 ml of the precursor solution was placed in a 3 L four-necked flask equipped with a stirring blade, a reflux condenser, a thermometer, and a dropping funnel, and the internal temperature was heated to 80 ° C. while rotating the stirring blade. To this, 6.52 ml of a 24% aqueous solution of ammonium persulfate was added, and a monomer mixture (28.5 g of glycidyl methacrylate, 21.4 g of ethyl acrylate, 21.4 g of methyl methacrylate) was dropped over 30 minutes. The reaction was continued for another 3 hours. Then, it cooled to 30 degrees C or less, and filtered, and prepared the solution (polyester component / acrylic component = 80/20) of the modified aqueous polyester A whose solid content concentration is 18 mass%.

[Preparation of transparent conductive film TC-2]
In the production of the transparent conductive film TC-1, except that the molecular weight of PVP used for the preparation of the silver nanowire dispersion W-1 was changed to 120,000 to produce silver nanowires having an average diameter of 50 nm and an average length of 40 μm. Similarly, a transparent conductive film TC-2 was produced.

[Preparation of transparent conductive film TC-3]
In the production of the transparent conductive film TC-1, except that the molecular weight of PVP used for the preparation of the silver nanowire dispersion W-1 was changed to 30,000 to produce silver nanowires having an average diameter of 120 nm and an average length of 25 μm. Similarly, a transparent conductive film TC-3 was produced.

[Preparation of transparent conductive film TC-4]
In producing the transparent conductive film TC-1, except that the fine particle ATO-containing liquid B-1 was changed to the following tin oxide sol-containing liquid B-2 and the dry film thickness of the transparent conductive metal oxide layer was changed to 500 nm. Thus, a translucent electrode TC-13 was produced.

<Tin oxide sol-containing liquid B-2>
SnO ₂ sol (Cerames S-8, Taki Chemical Co., Ltd., solid content 8%)
60g
Compound (UL-1) 0.02g
Modified aqueous polyester A (solid content 18%) 2g
Finish to 100 ml with water.

[Preparation of transparent conductive film TC-5]
In producing the transparent conductive film TC-1, except that the fine particle ATO-containing liquid B-1 was changed to the following fine particle ITO-containing liquid B-3, and the dry film thickness of the transparent conductive metal oxide layer was changed to 500 nm. Thus, a translucent electrode TC-5 was produced.

<Particle ITO-containing liquid B-3>
ITO fine particle dispersion (EI manufactured by Gemco Co., Ltd., solvent IPA, solid content 20%) 24 g
IPA (isopropyl alcohol) 73g
Modified aqueous polyester A (solid content 18%) 3g
[Preparation of transparent conductive film TC-6]
In producing the transparent conductive film TC-2, except that the fine particle ATO-containing liquid B-1 was changed to the following fine particle ATO-containing liquid B-4, and the dry film thickness of the transparent conductive metal oxide layer was changed to 500 nm. Thus, a translucent electrode TC-6 was produced.

<Fine particle ATO-containing liquid B-4>
Sb-doped SnO ₂ fine particles (SN100D manufactured by Ishihara Sangyo Co., Ltd., solid content 30%) 16 g
Compound (UL-1) 0.02g
Modified aqueous polyester A (solid content 18%) 6g
Finish to 100 ml with water.

[Preparation of transparent conductive film TC-7]
In producing the transparent conductive film TC-2, except that the fine particle ATO-containing liquid B-1 was changed to the following fine particle ATO-containing liquid B-5, and the dry film thickness of the transparent conductive metal oxide layer was changed to 500 nm. Thus, a translucent electrode TC-7 was produced.

<Fine particle ATO-containing liquid B-5>
Sb-doped SnO ₂ fine particles (SN100D manufactured by Ishihara Sangyo Co., Ltd., solid content 30%) 16 g
Compound (UL-1) 0.02g
Modified aqueous polyester A (solid content 18%) 9g
Finish to 100 ml with water.

[Preparation of transparent conductive film TC-8]
In the production of the transparent conductive film TC-1, the step of overcoating the transparent conductive metal oxide layer was omitted, and a transparent conductive film TC-8 was produced. That is, a biaxially stretched PET film is used as the transparent substrate, and the surface of the PET film is subjected to a corona discharge treatment, and then the silver nanowire dispersion W-1 is adjusted so that the basis weight of the silver nanowire is 80 mg / m ^2. A transparent conductive film TC-8 having silver nanowires was prepared by coating and drying using a wire bar.

[Preparation of transparent conductive film TC-9]
In the production of the transparent conductive film TC-2, the step of overcoating the transparent conductive metal oxide layer was omitted, and a transparent conductive film TC-9 was produced.

[Preparation of transparent conductive film TC-10]
In the production of the transparent conductive film TC-3, the step of overcoating the transparent conductive metal oxide layer was omitted, and a transparent conductive film TC-10 was produced.

[Evaluation of transparent conductive film]
The surface resistivity and total light transmittance (hereinafter, simply referred to as transmittance) of each of the produced transparent conductive films were measured by methods according to JIS K 7194: 1994 and JIS K 7361-1: 1997, respectively. In addition, the transparent conductive metal oxide layer coating solution used for each transparent conductive film is coated on a corona discharge-treated PET film to produce a uniform film, and the sheet resistance is measured by the same method. And the resistivity (conductive material resistivity) except the metal nanowire of the transparent conductive metal oxide layer was calculated from the film thickness.

Table 1 shows the obtained results.

From Table 1, it can be seen that the transparent conductive films TC-1 to TC-7 of the present invention have both high conductivity and good transparency compared with the comparative transparent conductive films TC-8 to TC-10.

Example 2
[Production of Display Element S-1]
A solution prepared by adding polyacrylic spherical beads having an average particle diameter of 20 μm to a volume fraction of 4% by volume to the electrolyte solution 1 and stirring the mixture is applied onto the electrode 2 below, and transparent from above. A display element S-1 was produced by combining the transparent conductive film TC-1 (produced in Example 1) cut into 1 cm × 3 cm as a surface electrode in the perpendicular direction. The overlapped 1 cm × 1 cm portion is a display portion (black / white solid), and the remaining portion is used as a lead portion. A sufficient amount of silver paste was applied to the lead portion.

(Preparation of electrolyte solution 1)
In 2.5 g of dimethyl sulfoxide, 90 mg of sodium iodide and 75 mg of silver iodide were added and completely dissolved, then 0.5 g of titanium oxide was added, and the titanium oxide was dispersed with an ultrasonic disperser. 150 mg of polyvinyl alcohol (saponification degree: about 87-89%, polymerization degree: 4500) was added to this solution and stirred for 1 hour while heating at 120 ° C. to obtain an electrolyte solution 1.

(Preparation of electrode 2)
A Cu film was formed on the entire surface of a 1.5 cm thick 1 cm × 5 cm glass substrate by a known sputtering method, and then 10 μm of silver was deposited on the Cu film by electrolytic plating to form a silver electrode (electrode 2). Obtained.

[Production of Display Elements S-2, 3, 5, 8 to 10]
In the production of the display element S-1, the transparent conductive film TC-1 (produced in Example 1) was changed to the transparent conductive film TC-2, 3, 5, 8 to 10 (produced in Example 1). In the same manner, display elements S-2, 3, 5, 8 to 10 were produced.

[Evaluation of display element]
For each manufactured display element, using a power source in which two single dry batteries are connected in series, connect-to the transparent electrode side and + to the electrode 2 side, and visually display the entire display state to display a minute area. The state was loupe observation.

As a result, the display elements S-2, 3, and 5 using the transparent electrode (transparent conductive film) of the present invention displayed a uniform black display both visually and with a magnifying glass. On the other hand, the display elements S-8 to 10 using the comparative transparent electrode have no problem in the visual evaluation, but when observed with an optical microscope, the window portion of the wire was not blackened. It can be seen that the transparent conductive film of the present invention functions as an effective transparent electrode over the entire surface.

DESCRIPTION OF SYMBOLS 1 Metal nanowire 2 Transparent electroconductive metal oxide layer 3 Transparent adhesive resin 4 Transparent base material

Claims

A transparent conductive film comprising a transparent conductive metal oxide layer containing metal nanowires on a transparent substrate.
2. The transparent conductive film according to claim 1, wherein a resistivity of the transparent conductive metal oxide layer excluding metal nanowires is 1 × 10 5 Ωcm or less.
The transparent conductive film according to claim 1 or 2, wherein an average primary particle size of the transparent conductive metal oxide contained in the transparent conductive metal oxide layer is 50 nm or less.
4. The transparent conductive film according to claim 3, wherein the transparent conductive metal oxide is formed from a transparent conductive metal oxide sol.
The transparent conductive film according to any one of claims 1 to 4, wherein the metal nanowire has an average diameter of 100 nm or less.
A transparent electrode comprising the transparent conductive film according to any one of claims 1 to 5.