Transparent conductive film

Abstract

To provide a transparent conductive film which offers superior light transmittance in the near-infrared region.SOLUTION: A transparent conductive film according to an embodiment of the present invention comprises a conductive layer, a base material, and a transmittance adjustment layer arranged in this order, the transmittance adjustment layer containing an ultraviolet-curable resin, solid particles, and hollow particles, where the solid particles have an average particle diameter that is 100% or less of an average particle diameter of the hollow particles.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a transparent conductive film.

Background Art

[0002] Conventionally, as a transparent conductive film used for electrodes of touch sensors and the like, a transparent conductive film in which a metal oxide layer such as an indium-tin composite oxide layer (ITO layer) is formed on a resin film has been widely used. In recent years, the use of a transparent conductive film as a heating element has been studied. For example, it may be used for covers of cameras, sensors, etc. used for automatic driving of automobiles for the purpose of snow melting and anti-fogging. In such use, it is required to have excellent conductivity and preferably transmit the light used. Here, in the above applications, in addition to visible light, the transmittance of light in the near-infrared region may also be required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made to solve the above problems, and its main object is to provide a transparent conductive film excellent in near-infrared light transmittance.

Means for Solving the Problems

[0005] [1] The transparent conductive film according to an embodiment of the present invention includes a conductive layer, a base material, and a transmittance adjustment layer in this order. The transmittance adjustment layer contains an ultraviolet curable resin, solid particles, and hollow particles, and the average particle diameter of the solid particles is 100% or less with respect to the average particle diameter of the hollow particles. [2] The transparent conductive film described in [1] above may be such that the ultraviolet curable resin is a cured product of a composition for forming a transmittance adjusting layer containing a polyfunctional monomer. [3] The transparent conductive film described in [2] above may be such that the composition for forming the transmittance adjusting layer contains a polyfunctional monomer having 4 or more reactive functional groups. [4] The transparent conductive film described in any one of [1] to [3] above may be such that the weight average particle diameter of the hollow particles is 30 nm to 100 nm. [5] The transparent conductive film described in any one of [1] to [4] above may be such that the content ratio of the solid particles is 130 parts by weight or less with respect to 100 parts by weight of the hollow particles. [Effect of the Invention]

[0006] According to an embodiment of the present invention, a transparent conductive film excellent in light transmittance in the near infrared region can be provided. [Brief Description of the Drawings]

[0007]

Figure 1

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0009] A. Overall structure of the transparent conductive film FIG. 1 is a schematic cross-sectional view of a transparent conductive film according to one embodiment of the present invention. The transparent conductive film 100 includes a conductive layer 10, a base material 20, and a transmittance adjusting layer 30 in this order. Although not shown, the transparent conductive film may further include any other appropriate layer. In FIG. 1, the conductive layer 10 is illustrated as having a configuration including fibrous conductive material 11, but is not limited thereto, and the conductive layer may be, for example, a layer made of a metal film or a layer made of a metal oxide film.

[0010] In one embodiment, the transparent conductive film 100 includes a protective layer 40 disposed on the side opposite to the base material 20 of the conductive layer 10. The protective layer 40 can be a layer that protects the fibrous conductive material 11. In the embodiments of the present invention, by providing the protective layer 40, the durability of the conductive layer 10 can be improved. More specifically, a conductive layer composed of a fibrous conductive material (for example, metal nanowire) has characteristics such as low scratch resistance and humidity durability. By providing a protective layer, these problems can be solved, and the durability of the conductive layer (and as a result, the durability of the transparent conductive film) can be improved. Note that the conductive layer 10 may contain components constituting the protective layer 40 (for example, the resin constituting the protective layer).

[0011] The transmittance adjustment layer includes an ultraviolet curable resin, solid particles, and hollow particles. By providing a transmittance adjustment layer containing hollow particles, the refractive index of the transmittance adjustment layer can be preferably adjusted, and the interface reflection of the transparent conductive film can be suppressed. As a result, a transparent conductive film excellent in light transmittance can be obtained. In particular, the transparent conductive film according to the embodiments of the present invention can be suitably used as a member that can efficiently transmit laser light (near-infrared region) required for sensing in the field of autonomous driving of vehicles using LiDAR (Light Detection And Ranging). In one embodiment, the transparent conductive film is used for a transparent heater (for example, a transparent heater for a vehicle). The transparent heater can have any suitable configuration. Typically, the transparent heater can be configured to generate heat by applying an electric current to a transparent conductive film on which a pair of electrodes are disposed. In the transparent heater, the transparent conductive film can be used as a heat source, which is advantageous in that it has excellent transmittance of near-infrared rays and can exhibit sufficient heat generation even at a low voltage.

[0012] On the one hand, the addition of hollow particles to the transmittance adjustment layer may cause mechanical strength of the transmittance adjustment layer and may be a cause of scratches during conveyance in a roll-to-roll process or the like. In an embodiment of the present invention, by adding solid particles, the slidability of the transmittance adjustment layer can be enhanced to form a transmittance adjustment layer that is less likely to be scratched. For example, it is possible to prevent scratches that are likely to occur during conveyance in a roll-to-roll process. Further, when the transparent conductive film is in a roll shape and the transmittance adjustment layer and the conductive layer are in contact with each other, damage to the conductive layer can be prevented.

[0013] In one embodiment, the average particle diameter of the solid particles is 100% or less with respect to the average particle diameter of the hollow particles. By reducing the particle diameter of the solid particles, a transmittance adjustment layer excellent in light transmittance can be formed. In an embodiment of the present invention, by adjusting the particle diameter of the solid particles, a transmittance adjustment layer excellent in light transmittance can be formed while exhibiting high slidability. The average particle diameter of the solid particles is preferably 80% or less, more preferably 60% or less, and still more preferably 40% or less with respect to the average particle diameter of the hollow particles. If it is in such a range, the above effects become remarkable.

[0014] In one embodiment, the maximum transmittance (T1max) of the transparent conductive film at a wavelength of 780 nm to 1600 nm and the maximum transmittance (T2max) of a laminate composed of the conductive layer and the base material constituting the transparent conductive film at a wavelength of 780 nm to 1600 nm satisfy the following formula. ((T1max - T2max) / T2max)×100 ≧ 3% Note that the "laminate composed of the conductive layer and the base material constituting the transparent conductive film" is a laminate composed of the base material and the conductive layer disposed on one surface of the base material, and can be, for example, a configuration obtained by removing the transmittance adjustment layer from the transparent conductive film. Further, in this specification, the value represented by ((T1max - T2max) / T2max)×100 is also referred to as the transmittance increase rate due to the transmittance adjustment layer.

[0015] 「((T1max - T2max) / T2max) × 100」is preferably 3.5% or more, more preferably 4% or more. If it is within such a range, the above effects will be remarkable. The upper limit of 「((T1max - T2max) / T2max) × 100」is, for example, 10%.

[0016] The maximum transmittance (T1max) of the transparent conductive film at a wavelength of 780 nm to 1600 nm is preferably 85% or more, more preferably 90% or more, and still more preferably 94% or more. The higher the maximum transmittance (T1max) of the transparent conductive film at a wavelength of 780 nm to 1600 nm, the more preferable it is, but the upper limit is, for example, 96% (preferably 98%).

[0017] The maximum transmittance (T2max) of the laminate composed of the conductive layer and the base material constituting the transparent conductive film at a wavelength of 780 nm to 1600 nm is, for example, 80% to 95%.

[0018] In one embodiment, the maximum transmittance (T3max) of the transparent conductive film at a wavelength of 380 nm to 780 nm and the maximum transmittance (T4max) of the laminate composed of the conductive layer and the base material constituting the transparent conductive film at a wavelength of 380 nm to 780 nm satisfy the following formula. ((T3max - T4max) / T4max) × 100 ≧ 2% 「((T3max - T4max) / T4max) × 100」is preferably 2.5% or more, more preferably 3.5% or more. The upper limit of 「((T3max - T4max) / T4max) × 100」is, for example, 8%.

[0019] The maximum transmittance (T3max) of the transparent conductive film at a wavelength of 380 nm to 780 nm is preferably 85% or more, more preferably 90% or more, and still more preferably 94% or more. The higher the maximum transmittance (T3max) of the transparent conductive film at a wavelength of 380 nm to 780 nm, the more preferable it is, but the upper limit is, for example, 96% (preferably 98%).

[0020] The maximum transmittance (T4max) of the laminate composed of the conductive layer and the substrate that constitutes the transparent conductive film at a wavelength of 380 nm to 780 nm is, for example, 80% to 95%.

[0021] The light transmittance of the above transparent conductive film at a wavelength of 905 nm is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. If it is within such a range, a transparent conductive film suitable for applications that transmit laser light in the near-infrared region can be provided. The higher the light transmittance at a wavelength of 905 nm, the more preferable, but the upper limit is, for example, 95% (preferably 98%).

[0022] The light transmittance of the above transparent conductive film at a wavelength of 555 nm is preferably 80% or more, more preferably 85% to 95%.

[0023] The haze of the above transparent conductive film is preferably 0.1% to 3.0%, more preferably 0.1% to 1.5%.

[0024] The surface resistance value of the above transparent conductive film is 200 Ω / sq or less, preferably 0.01 Ω / sq to 200 Ω / sq, more preferably 1 Ω / sq to 180 Ω / sq, particularly preferably 5 Ω / sq to 150 Ω / sq, and most preferably 10 Ω / sq to 100 Ω / sq. In one embodiment, the surface resistance value of the transparent conductive film is 50 Ω / sq or less. If it is within such a range, a particularly suitable transparent conductive film can be obtained for transparent heater applications (especially for vehicle transparent heaters). For example, a heater that can generate heat at a low voltage can be realized.

[0025] The thickness of the above transparent conductive film is preferably 10 μm to 500 μm, more preferably 15 μm to 300 μm, and even more preferably 20 μm to 200 μm.

[0026] In one embodiment, the ratio of the thickness of the base material to the thickness of the transmittance adjustment layer (thickness of the base material / thickness of the transmittance adjustment layer) is preferably 90 to 800, more preferably 95 to 750. Within such a range, reflection of near-infrared rays (for example, light with a wavelength of 780 nm to 1600 nm) can be suppressed, and as a result, a transparent conductive film excellent in near-infrared transmittance can be obtained. In one embodiment, the ratio of the thickness of the base material to the thickness of the transmittance adjustment layer (thickness of the base material / thickness of the transmittance adjustment layer) is 100 or more (preferably 130 or more, more preferably 150 or more). Within such a range, a transparent conductive film with less interference unevenness can be obtained.

[0027] B. Conductive layer The conductive layer can have any suitable configuration as long as the effects of the present invention can be obtained. In one embodiment, as shown in FIG. 1, the conductive layer 10 includes a fibrous conductive material 11. By forming such a conductive layer, a transparent conductive film excellent in light transmittance, conductivity, and flexibility can be obtained. A transparent conductive film provided with a conductive layer containing a fibrous conductive material is also advantageous in terms of excellent heat generation characteristics, and can be preferably used, for example, as an anti-fog heater (transparent heater) for vehicle window glass. Examples of the fibrous conductive material include metal nanowires and carbon nanotubes. Preferably, metal nanowires are used. In one embodiment, the conductive layer includes a fibrous conductive material and a polymer matrix. The fibrous conductive material can be protected by the polymer matrix. As a result, corrosion of the fibrous conductive material is prevented, and a transparent conductive film with more excellent durability can be obtained.

[0028] The thickness of the conductive layer is preferably 50 nm to 300 nm, more preferably 80 nm to 200 nm.

[0029] (Fibrous conductive material) As the fibrous conductive material, metal nanowires can be preferably used.

[0030] A metal nanowire refers to a conductive material that is made of metal, has a needle-like or thread-like shape, and a diameter in the nanometer size range. The metal nanowire may be linear or curved. By using a conductive layer composed of metal nanowires, since the metal nanowires form a mesh-like pattern, even a small amount of metal nanowires can form a good electrical conduction path, and a transparent conductive film with low electrical resistance can be obtained. Furthermore, since the metal nanowires form a mesh-like pattern, openings are formed in the gaps between the meshes, and a transparent conductive film with high light transmittance can be obtained.

[0031] The ratio (aspect ratio: L / d) of the thickness d to the length L of the above fibrous conductive material (preferably, a metal nanowire) is preferably 10 to 100,000, more preferably 50 to 100,000, and particularly preferably 100 to 10,000. By using a fibrous conductive material with such a large aspect ratio, the fibrous conductive materials can cross well, and high conductivity can be exhibited by a small amount of fibrous conductive materials. As a result, a transparent conductive film with high light transmittance can be obtained. In this specification, the "thickness of the fibrous conductive material" means the diameter when the cross-section of the fibrous conductive material is circular, the minor axis when it is elliptical, and the longest diagonal line when it is polygonal. The thickness and length of the fibrous conductive material can be confirmed by a scanning electron microscope or a transmission electron microscope.

[0032] The thickness of the above fibrous conductive material (preferably, a metal nanowire) is preferably less than 500 nm, more preferably less than 200 nm, particularly preferably 10 nm to 100 nm, and most preferably 10 nm to 50 nm. If it is within such a range, a conductive layer with high light transmittance can be formed.

[0033] The length of the above fibrous conductive material (preferably, a metal nanowire) is preferably 1 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 10 μm to 100 μm. If it is within such a range, a transparent conductive film with high conductivity can be obtained.

[0034] As the metal constituting the metal nanowire, any appropriate metal can be used as long as it is a conductive metal. Examples of the metal constituting the metal nanowire include silver, gold, copper, nickel, and the like. Further, a material obtained by subjecting these metals to plating treatment (for example, gold plating treatment) may be used. Among them, preferably, from the viewpoint of conductivity, it is silver, copper or gold, and more preferably silver.

[0035] As the method for producing the metal nanowire, any appropriate method can be adopted. For example, a method of reducing silver nitrate in a solution, a method of applying a voltage or current from the tip of a probe to the surface of a precursor to draw out a metal nanowire at the tip of the probe and continuously form the metal nanowire, and the like can be mentioned. In the method of reducing silver nitrate in a solution, silver nanowires can be synthesized by liquid-phase reduction of a silver salt such as silver nitrate in the presence of a polyol such as ethylene glycol and polyvinylpyrrolidone. Uniform-sized silver nanowires can be mass-produced, for example, according to the methods described in Xia, Y. et al., Chem. Mater. (2002), 14, 4736-4745, and Xia, Y. et al., Nano letters (2003) 3(7), 955-960.

[0036] The content ratio of the fibrous conductive material (preferably, metal nanowire) in the conductive layer is preferably 30% by weight to 90% by weight, and more preferably 45% by weight to 80% by weight with respect to the total weight of the conductive layer. Within such a range, a transparent conductive film excellent in conductivity and light transmittance can be obtained.

[0037] When the metal nanowire is a silver nanowire, the density of the conductive layer is preferably 1.3 g / cm 3 ~10.5 g / cm 3 and more preferably 1.5 g / cm 3 ~3.0 g / cm 3 Within such a range, a transparent conductive film excellent in conductivity and light transmittance can be obtained.

[0038] In one embodiment, the conductive layer is patterned. As the patterning method, any appropriate method can be adopted according to the form of the conductive layer. The shape of the pattern of the conductive layer can be any appropriate shape according to the application. For example, the patterns described in JP-T-2011-511357, JP-A-2010-164938, JP-A-2008-310550, JP-T-2003-511799, and JP-T-2010-541109 can be mentioned. After the conductive layer is formed on the substrate, it can be patterned using any appropriate method according to the form of the conductive layer.

[0039] In one embodiment, the metal nanowires in the conductive layer have a fused network structure. The metal nanowires having a fused network structure are in a state where the metal nanowires are fused at the contact points. By forming a conductive layer containing metal nanowires having a fused network structure, a transparent conductive film with higher conductivity can be obtained without impairing transparency.

[0040] The conductive layer containing metal nanowires having the fused network structure can be formed, for example, by adding an additive for promoting fusion to the metal nanowire dispersion used when forming the conductive layer. Examples of the additive include metal halides (for example, LiCl, CsCl, NaF, NaCl, NaBr, NaI, KCl, MgCl 2 , CaCl 2 , AlCl 3, AgF, etc.), inorganic acids (e.g., nitric acid, nitrous acid, sulfuric acid, etc.), organic acids (e.g., oxalic acid, citric acid, formic acid, acetic acid, lactic acid, propionic acid, butyric acid, acrylic acid, pyruvic acid, trichloroacetic acid, trifluoroacetic acid, hexanoic acid, octanoic acid, decanoic acid, dodecanoic (lauric) acid, tetradecanoic (myristic) acid, hexadecanoic (palmitic) acid, octadecanoic (stearic) acid, 2-ethylbutyric acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, 2-propylpentanoic acid, pivalic acid, neoheptanoic acid, neononanoic acid, neodecanoic acid, etc.), silver salts (e.g., silver nitrate, silver nitrite, silver lactate, silver chloride, silver sulfate, silver oxide, silver acetate, silver chlorate, silver sulfide, etc., silver formate, silver hexanoate, silver octanoate, silver decanoate, silver dodecanoate, silver tetradecanoate, silver hexadecanoate, silver octadecanoate, silver pentanoate, silver pivalate, silver neoheptanoate, silver neononanoate, silver neodecanoate, etc.), elements capable of forming silver salts (chlorine, sulfur, etc.) and compounds containing them (hydrogen chloride, sodium chloride, etc.). Among them, metal halides are preferred, and more preferably, NaCl, AgF, LiF, NaBr, or NaF. In one embodiment, the conductive layer containing metal nanowires having the fused network structure can be formed by applying a metal nanowire dispersion containing the above additives and then performing heat treatment and / or pressure treatment. The temperature of the heat treatment is, for example, 50°C to 200°C.

[0041] The conductive layer containing metal nanowires having the fused network structure may be formed by exposing the coating layer of the metal nanowire dispersion to acid halide vapor. Examples of the acid halide vapor include vapors such as HCl, HBr, HI, or mixtures thereof.

[0042] Metal nanowires having a fused network structure and a method for producing the same are described, for example, in Japanese Patent Application Publication No. 2015-530693. The description of this publication is incorporated herein by reference.

[0043] (polymer matrix) As the polymer constituting the polymer matrix, any suitable polymer can be used. Examples of the polymer include acrylic polymers; polyester polymers such as polyethylene terephthalate; aromatic polymers such as polystyrene, polyvinyltoluene, polyvinylxylene, polyimide, polyamide, and polyamideimide; polyurethane polymers; epoxy polymers; polyolefin polymers; acrylonitrile-butadiene-styrene copolymer (ABS); cellulose; silicone polymers; polyvinyl chloride; polyacetate; polynorbornene; synthetic rubber; fluorine-based polymers, and the like. Preferably, a curable resin (preferably an ultraviolet curable resin) composed of polyfunctional acrylates such as pentaerythritol triacrylate (PETA), neopentyl glycol diacrylate (NPGDA), dipentaerythritol hexaacrylate (DPHA), dipentaerythritol pentaacrylate (DPPA), trimethylolpropane triacrylate (TMPTA), etc. is used. The polymer matrix can be the resin constituting the protective layer (details will be described later).

[0044] The polymer matrix can be formed by forming a layer composed of a fibrous conductive material on a substrate, then applying a polymer solution on the layer, and then drying or curing the applied layer. By this operation, a conductive layer in which the fibrous conductive material is present in the polymer matrix is formed. The polymer solution contains the polymer constituting the polymer matrix or a precursor of the polymer (a monomer constituting the polymer). The polymer solution may contain a solvent. Examples of the solvent contained in the polymer solution include alcohol solvents, ketone solvents, tetrahydrofuran, hydrocarbon solvents, or aromatic solvents, etc. Preferably, the solvent is volatile. The boiling point of the solvent is preferably 200 °C or lower, more preferably 150 °C or lower, and even more preferably 100 °C or lower.

[0045] (Metal film-based conductive layer) The above conductive layer may be a layer made of a metal film or a metal oxide film. As materials constituting such a conductive layer, for example, metals such as Cu, Al, Fe, Cr, Ti, Si, Nb, In, Zn, Sn, Au, Ag, Co, Cr, Ni, Pb, Pd, Pt, W, Zr, Ta, Hf, Mo, Mn, Mg, V, etc. are preferably used. In addition, those containing two or more of these metals, alloys, oxides, etc. having these metals as main components can also be used. For example, indium-tin composite oxide (ITO) can be used.

[0046] C. Transmittance adjustment layer The refractive index of the above transmittance adjustment layer is preferably 1.45 or less, more preferably 1.40 or less, still more preferably 1.30 or less, further preferably 1.25 or less, and particularly preferably 1.20 or less. By providing a transmittance adjustment layer having a refractive index in such a range, interface reflection of the transparent conductive film can be suppressed. As a result, a transparent conductive film excellent in light transmittance can be obtained. The lower the refractive index of the low refractive index layer, the more preferable, but the lower limit thereof is, for example, 1.07 or more (preferably 1.05 or more). The refractive index of the transmittance adjustment layer can be adjusted by the inclusion of hollow particles. In this specification, the refractive index refers to the refractive index measured at a wavelength of 550 nm.

[0047] The thickness of the transmittance adjustment layer is preferably 120 nm or more, more preferably 150 nm to 1000 nm, and still more preferably 170 nm to 600 nm. If it is in such a range, reflection of near-infrared rays (for example, light having a wavelength of 780 nm to 1600 nm) can be suppressed, and as a result, a transparent conductive film excellent in near-infrared transmittance can be obtained. In addition, a transmittance adjustment layer excellent in slidability and difficult to be scratched can be formed. In one embodiment, the thickness of the transmittance adjustment layer is less than 510 nm (preferably 500 nm or less, more preferably 400 nm or less). If it is in such a range, a transparent conductive film with less interference unevenness can be obtained.

[0048] The arithmetic surface roughness Ra of the above transmittance adjustment layer is preferably 1.5 nm or more, more preferably 2 nm or more, and still more preferably 3 nm or more. If it is within such a range, it is possible to form a transmittance adjustment layer that maintains favorable light transmittance, has excellent slipperiness, and is less likely to be scratched. The upper limit of the arithmetic surface roughness Ra of the transmittance adjustment layer can be, for example, 50 nm, 40 nm, or 30 nm. The surface shape of the transmittance adjustment layer can be adjusted, for example, by adding particles (such as hollow particles, solid particles, etc.) to the transmittance adjustment layer. The arithmetic surface roughness Ra can be measured according to JIS B 0601.

[0049] The maximum height roughness Rz of the above transmittance adjustment layer is preferably 12 nm or more, more preferably 20 nm or more, and still more preferably 30 nm or more. If it is within such a range, it is possible to form a transmittance adjustment layer that is particularly excellent in slipperiness and is less likely to be scratched. The upper limit of the maximum height roughness Rz of the transmittance adjustment layer can be, for example, 80 nm, 70 nm, or 60 nm. The maximum height roughness Rz of the transmittance adjustment layer can be measured according to JIS B 0601-2001.

[0050] (UV curable resin) As described above, a UV curable resin is used as the resin constituting the transmittance adjustment layer. By using a UV curable resin, a transparent conductive film excellent in scratch resistance can be obtained. In addition, since the transmittance adjustment layer can be formed without heating, damage to the hollow particles can be prevented.

[0051] As the above UV curable resin, for example, resins having curable acrylate groups and / or methacrylate groups can be used. Examples include silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as polyhydric alcohols. These can be used alone or in combination of two or more.

[0052] In one embodiment, a cured product of a composition for forming a transmittance adjustment layer containing a (meth)acrylate monomer and / or a (meth)acrylate oligomer is used as the ultraviolet curable resin. Specific examples of the (meth)acrylate monomer and the (meth)acrylate oligomer include, for example, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tetra(meth)acrylate, tris(acryloxyethyl)isocyanurate, caprolactone-modified tris(acryloxyethyl)isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, alkyl-modified dipentaerythritol tetra(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like. Among them, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, or dipentaerythritol penta(meth)acrylate is preferable. Also, urethane acrylate may be used. Examples of urethane acrylate include phenylglycamyl ether acrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer. The above monomers and polymers may be used alone or in combination of two or more.

[0053] In one embodiment, the composition for forming a transmittance adjustment layer contains a polyfunctional monomer, preferably a polyfunctional acrylate. A polyfunctional monomer means a monomer having two or more reactive functional groups. A reactive functional group is a functional group that can be crosslinked by irradiation with ultraviolet light, that is, a functional group having a multiple bond, and examples thereof include an alkenyl group, an alkynyl group, a vinyl group, an acrylic group, a methacrylate group, an allyl group, and the like. In the composition for forming a transmittance adjustment layer, the content ratio of the polyfunctional monomer is preferably 50 parts by weight or more, more preferably 70 parts by weight or more, still more preferably 90 parts by weight or more, based on 100 parts by weight of the monomer component. In one embodiment, the content ratio of the polyfunctional monomer is 100 parts by weight based on 100 parts by weight of the monomer component.

[0054] In one embodiment, the above polyfunctional monomer preferably has three or more reactive functional groups, and more preferably has four or more reactive functional groups. The upper limit of the reactive functional groups possessed by the polyfunctional monomer is, for example, six.

[0055] The composition for forming the transmittance adjustment layer contains any suitable photoinitiator. Examples of the photoinitiator include benzoin ethers such as benzoin normal butyl ether and benzoin isobutyl ether, benzyl ketals such as benzyldimethyl ketal and benzyldiethyl ketal, acetophenones such as 2,2-dimethoxyacetophenone and 2,2-diethoxyacetophenone, α-hydroxyalkylphenones such as 1-hydroxycyclohexyl phenyl ketone, [2-hydroxy-2-methyl-1-(4-ethylphenyl)propan-1-one], 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-2-methyl-1-(4-isopropylphenyl)propan-1-one, α-aminoalkylphenones such as 2-methyl-1-[4-(methylthio)phenyl]-1-morpholinopropane and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, monoacylphosphine oxides such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide and 2,4,6-trimethylbenzoyl phenyl ethoxyphosphine oxide, and monoacylphosphine oxides such as bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0056] The composition for forming the transmittance adjustment layer may contain any suitable solvent. Examples of the solvent include MIBK (methyl isobutyl ketone), PGM (propylene glycol monomethyl ether), PMA (propylene glycol monomethyl ether acetate), TBA (tertiary butyl alcohol), and the like. A mixed solvent of these solvents may also be used.

[0057] (Hollow particles, solid particles) As described above, the transmittance adjustment layer contains hollow particles. Examples of the hollow particles include silica particles, acrylic particles, acrylic-styrene copolymer particles, and the like. Examples of the silica particles include those with the trade names "Throughia 5320" and "Throughia 4320" manufactured by JGC Catalysts and Chemicals Ltd.

[0058] The weight average particle diameter of the hollow particles may be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, and may also be 150 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, or 80 nm or less. In one embodiment, the weight average molecular weight of the hollow particles is 30 nm to 100 nm. Within such a range, a transparent conductive film with excellent slidability can be obtained while preferably maintaining light transmittance. The weight average particle diameter can be measured by a dynamic light scattering device (DLS). The shape of the hollow particles is not particularly limited. For example, they may be bead-shaped and substantially spherical, or may be amorphous such as powder, but substantially spherical ones are preferred, more preferably substantially spherical particles with an aspect ratio of 1.5 or less, and most preferably spherical particles.

[0059] The content ratio of the hollow particles is preferably 50 parts by weight to 200 parts by weight, more preferably 60 parts by weight to 160 parts by weight, and still more preferably 70 parts by weight to 150 parts by weight with respect to 100 parts by weight of the ultraviolet curable resin. Within such a range, the effects of the present invention become remarkable.

[0060] The hollow ratio of the hollow particles is preferably 30% to 70%, more preferably 40% to 60%, and still more preferably 40% to 50%. Within such a range, a transmittance adjustment layer with preferably adjusted refractive index can be formed, and a transmittance adjustment layer with excellent slidability and being difficult to be scratched can be formed while maintaining preferable light transmittance. The hollow ratio is represented by the formula: hollow ratio = {(volume of voids) / (volume of hollow particles)} × 100.

[0061] As described above, the transmittance adjustment layer contains solid particles. Examples of the solid particles include silica particles, zirconium oxide particles, titanium-containing particles (e.g., titanium oxide particles), and the like. Examples of the silica particles include those with trade names "MEK-2140Z-AC", "MIBK-ST", "IPA-ST", etc. manufactured by Nissan Chemical Industries, Ltd.

[0062] The weight average particle diameter of the solid particles may be, for example, 3 nm or more, 5 nm or more, 10 nm or more, and may also be less than 60 nm, 40 nm or less, 30 nm or less, 20 nm or less. The shape of the solid particles is not particularly limited. For example, it may be bead-shaped and substantially spherical, or may be amorphous such as powder. However, substantially spherical particles are preferred, more preferably substantially spherical particles with an aspect ratio of 1.5 or less, and most preferably spherical particles.

[0063] The content ratio of the solid particles is preferably 25 parts by weight to 200 parts by weight, more preferably 30 parts by weight to 180 parts by weight, still more preferably 40 parts by weight to 150 parts by weight, and particularly preferably 40 parts by weight to 120 parts by weight with respect to 100 parts by weight of the ultraviolet curable resin. Within such a range, a transmittance adjustment layer with preferably adjusted light transmittance and slidability can be formed.

[0064] The content ratio of the solid particles is preferably 130 parts by weight or less, more preferably 100 parts by weight or less, still more preferably 80 parts by weight or less with respect to 100 parts by weight of the hollow particles. Also, the content ratio of the solid particles is preferably 20 parts by weight or more, more preferably more than 25 parts by weight, still more preferably 50 parts by weight or more with respect to 100 parts by weight of the hollow particles. If the content ratio of the solid particles is within the above range, a transmittance adjustment layer with preferably adjusted light transmittance and slidability can be formed.

[0065] D. Substrate The above-mentioned substrate is typically composed of any suitable resin. Examples of the resin constituting the above-mentioned substrate include, for example, cycloolefin-based resins, polyimide-based resins, polyvinylidene chloride-based resins, polyvinyl chloride-based resins, polyethylene terephthalate-based resins, polyethylene naphthalate-based resins, and the like. Preferably, a cycloolefin-based resin is used.

[0066] The glass transition temperature of the resin constituting the above-mentioned substrate is preferably 50°C to 200°C, more preferably 60°C to 180°C, and even more preferably 70°C to 160°C.

[0067] The thickness of the above-mentioned substrate is preferably 8 μm to 500 μm, more preferably 10 μm to 250 μm, even more preferably 10 μm to 150 μm, and particularly preferably 15 μm to 100 μm.

[0068] The total light transmittance of the above-mentioned substrate is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. Within such a range, a transparent conductive film suitable as a transparent conductive film provided in a transparent heater or the like can be obtained.

[0069] The tensile breaking strength of the above-mentioned substrate at 23°C is preferably 30 MPa to 100 MPa, more preferably 50 MPa to 95 MPa, and even more preferably 70 MPa to 90 MPa. According to the present invention, even when using a film with poor flexibility, sufficient flexibility can be exhibited as a transparent conductive film. The tensile breaking strength is measured in accordance with JIS K 7161 at room temperature (23°C).

[0070] The above-mentioned substrate may further contain any suitable additive as required. Specific examples of the additive include plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, and thickeners. The type and amount of the additive used can be appropriately set according to the purpose.

[0071] If necessary, various surface treatments may be performed on the above-mentioned substrate. Any appropriate method may be adopted for the surface treatment according to the purpose. For example, low-pressure plasma treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be mentioned. In one embodiment, the transparent substrate is surface-treated to hydrophilize the surface of the transparent substrate. If the substrate is hydrophilized, the processability is excellent when applying the composition for forming a conductive layer prepared with an aqueous solvent. In addition, a transparent conductive film excellent in adhesion between the substrate and the conductive layer can be obtained. Further, the substrate may have a multilayer structure, for example, it may be composed of a resin film and other layers formed on the resin film.

[0072] E. Protective layer The thickness of the above-mentioned protective layer is preferably 10 nm to 1000 nm, more preferably 60 nm to 800 nm. If it is in such a range, a transparent conductive film excellent in durability can be obtained.

[0073] The total thickness of the above-mentioned conductive layer and the protective layer is preferably 60 nm to 1000 nm, more preferably 70 nm to 800 nm. If it is in such a range, a transparent conductive film excellent in durability can be obtained.

[0074] Typically, the above-mentioned protective layer is composed of a resin. As the resin constituting the protective layer, any appropriate resin can be used as long as the effects of the present invention can be obtained. Examples of the resin include acrylic resins; polyester resins such as polyethylene terephthalate; aromatic resins such as polystyrene, polyvinyltoluene, polyvinylxylene, polyimide, polyamide, and polyamideimide; polyurethane resins; epoxy resins; polyolefin resins; acrylonitrile-butadiene-styrene copolymer (ABS); cellulose; silicone resins; polyvinyl chloride; polyacetate; polynorbornene; synthetic rubbers; fluorine-based resins, etc.

[0075] In one embodiment, a curable resin (for example, an active energy ray curable resin, a thermosetting resin) is used as the resin for forming the protective layer. The protective layer composed of the curable resin can be formed by curing a composition for forming a curable protective layer.

[0076] In one embodiment, as the curable resin, a cured product of a composition for forming a curable protective layer containing a (meth)acrylate monomer and / or a (meth)acrylate oligomer is used. By using such a resin, a protective layer with preferably adjusted shear strength can be obtained. Specific examples of the (meth)acrylate monomer and the (meth)acrylate oligomer include, for example, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tetra(meth)acrylate, tris(acryloxyethyl) isocyanurate, caprolactone-modified tris(acryloxyethyl) isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, alkyl-modified dipentaerythritol tetra(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like. Among them, preferably, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, or dipentaerythritol penta(meth)acrylate. The above monomers and polymers may be used alone or in combination of two or more.

[0077] In one embodiment, as the curable resin, a cured product of a composition for forming a curable protective layer containing a urethane (meth)acrylate oligomer is used. By using such a resin, a protective layer with preferably adjusted shear strength can be obtained. Examples of the urethane (meth)acrylate oligomer include an oligomer obtained by reacting a polyol and a polyisocyanate and then reacting a (meth)acrylate having a hydroxyl group, an oligomer obtained by reacting a polyisocyanate and a (meth)acrylate having a hydroxyl group and then reacting a polyol, and an oligomer obtained by reacting a polyisocyanate, a polyol, and a (meth)acrylate having a hydroxyl group.

[0078] Examples of the polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol and their copolymers, ethylene glycol, propylene glycol, 1,4-butanediol, 2,2'-thiodiethanol, and the like.

[0079] Examples of the polyisocyanate include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and the like.

[0080] Preferably, the composition for forming a curable protective layer contains any suitable photoinitiator. Examples of photoinitiators include benzoin ethers such as benzoin normal butyl ether and benzoin isobutyl ether, benzyl ketals such as benzyldimethyl ketal and benzyldiethyl ketal, acetophenones such as 2,2-dimethoxyacetophenone and 2,2-diethoxyacetophenone, α-hydroxyalkylphenones such as 1-hydroxycyclohexyl phenyl ketone, [2-hydroxy-2-methyl-1-(4-ethylphenyl)propan-1-one], 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-2-methyl-1-(4-isopropylphenyl)propan-1-one, α-aminoalkylphenones such as 2-methyl-1-[4-(methylthio)phenyl]-1-morpholinopropane and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, monoacylphosphine oxides such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide and 2,4,6-trimethylbenzoyl phenyl ethoxyphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc.

[0081] F. Manufacturing method of the transparent conductive film The above-mentioned transparent conductive film can be manufactured by any suitable method. In one embodiment, a composition for forming a transmittance adjustment layer is applied to one surface of a substrate, and a composition for forming a conductive layer is applied to the other surface of the substrate, whereby a transparent conductive film can be obtained. When the transparent conductive film includes a protective layer, after applying the composition for forming a conductive layer to form a conductive layer, a composition for forming a protective layer (polymer solution) is applied, whereby a transparent conductive film can be obtained. Further, a metal nanowire may be contained in the composition for forming a protective layer, and the composition for forming a protective layer containing the metal nanowire may be applied to a substrate to obtain a transparent conductive film.

[0082] In one embodiment, the above-mentioned composition for forming a conductive layer contains the above-mentioned fibrous conductive material. The composition for forming a conductive layer may contain any suitable solvent in addition to the fibrous conductive material. The composition for forming a conductive layer can be prepared as a dispersion of the fibrous conductive material. Examples of the solvent include water, alcohol-based solvents, ketone-based solvents, ether-based solvents, hydrocarbon-based solvents, aromatic-based solvents, etc. From the viewpoint of reducing environmental impact, it is preferable to use water. The composition for forming a conductive layer may further contain any suitable additive according to the purpose. Examples of the additive include a corrosion inhibitor for preventing corrosion of the fibrous conductive material, a surfactant for preventing aggregation of the fibrous conductive material, etc. The type, number, and amount of the additive used can be appropriately set according to the purpose.

[0083] The dispersion concentration of the fibrous conductive material in the above-mentioned composition for forming a conductive layer is preferably 0.1 wt% to 1 wt%. Within such a range, a conductive layer excellent in conductivity and light transmittance can be formed.

[0084] As the method for applying the composition for forming the conductive layer, any appropriate method can be adopted. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, relief printing method, intaglio printing method, gravure printing method, etc. As the drying method for the coating layer, any appropriate drying method (e.g., natural drying, air drying, heat drying) can be adopted. For example, in the case of heat drying, the drying temperature is typically 50°C to 200°C, preferably 80°C to 150°C. The drying time is typically 1 minute to 10 minutes.

[0085] The conductive layer (e.g., a layer made of a metal film or a layer made of a metal oxide film) may be formed by any appropriate film-forming method (e.g., vacuum evaporation method, sputtering method, CVD method, ion plating method, spray method, etc.). Since the film-forming method is a method known to those skilled in the art, a detailed description thereof will be omitted.

[0086] The composition for forming the transmittance adjustment layer uses the composition described in Item C. The solid content concentration of the composition for forming the transmittance adjustment layer is, for example, 0.1% by weight to 20% by weight, preferably 1% by weight to 10% by weight.

[0087] As the method for applying the transmittance adjustment layer composition, any appropriate method can be adopted. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, relief printing method, intaglio printing method, gravure printing method, etc. As the drying method for the coating layer, any appropriate drying method (e.g., natural drying, air drying, heat drying) can be adopted. For example, in the case of heat drying, the drying temperature is typically 50°C to 200°C, preferably 80°C to 150°C. The drying time is typically 1 minute to 10 minutes.

[0088] When using a composition for forming a transmittance adjustment layer containing a curable resin, after applying the composition for forming a transmittance adjustment layer, a curing treatment is performed. As the method of the curing treatment, any appropriate method is adopted according to the composition of the composition for forming a transmittance adjustment layer. As the method of the curing treatment, for example, after heating and drying the coating layer, using an ultraviolet irradiation machine at 500 mW / cm 2 ~3000 mW / cm 2 of irradiation intensity, ultraviolet rays with a work amount of 50 mJ / cm 2 ~400 mJ / cm 2 are irradiated.

[0089] The composition for forming a protective layer contains a resin for forming a protective layer or its precursor (monomer, oligomer). The composition for forming a protective layer may further contain any appropriate additive as necessary. For example, a photopolymerization initiator, a coupling agent, etc. may be contained. Further, the composition for forming a protective layer may further contain any appropriate solvent for dilution. Examples of the solvent include toluene, butyl acetate, isobutanol, ethyl acetate, cyclohexane, cyclohexanone, methylcyclohexanone, hexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, diethyl ether, ethylene glycol, etc.

[0090] As the coating method of the composition for forming a protective layer, any appropriate method can be adopted. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, relief printing method, intaglio printing method, gravure printing method, etc.

[0091] When using a composition for forming a curable protective layer, after applying the composition for forming a curable protective layer, a curing treatment is performed. As the method of the curing treatment, any appropriate method is adopted according to the composition of the composition for forming a curable protective layer. As the method of the curing treatment, for example, after heating and drying the above solvent, using an ultraviolet irradiation machine at 500 mW / cm 2 ~3000 mW / cm 2At an irradiation intensity of 50 mJ / cm 2 ~400 mJ / cm 2 There is a method of irradiating ultraviolet rays of

Example

[0092] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The measurement methods for each property are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight. (1) Surface resistance The surface resistance value of the transparent conductive film (conductive layer) was measured using "EC-80" manufactured by NAPSON. The measurement temperature was 23°C. (2) Transmittance In a predetermined wavelength range (905 nm), the transmittance was measured at room temperature using the transmittance measurement mode of "Hitachi Spectrophotometer U-4100" manufactured by Hitachi High-Tech Science Corporation. (3) Haze Measurement was performed in accordance with JIS K 7136 using a haze meter SH 7000 (manufactured by Nippon Denshoku Industries Co., Ltd.). (4) Anti-blocking property A cycloolefin polymer film (COP film, "Zeonor" manufactured by Zeon Corporation, Japan) was placed on the surface of the transmittance adjustment layer of the transparent conductive film, and a load was applied by finger pressure to evaluate the adhesion of the film. When the COP film did not adhere to the transparent conductive film at all, or when the COP film adhered slightly but immediately separated (when it fell naturally due to gravity), it was evaluated as "OK", and when the COP film adhered and did not separate, it was evaluated as "NG". (5) Average inclination angle (θa) of the uneven portion Using a surface roughness measuring instrument: ET-4000A manufactured by Kosaka Laboratory Ltd., in accordance with JIS B 0601-2001, with a material: diamond and a stylus with an apex angle of 60°C, θa was measured.

[0093] [Example 1] (1. Preparation of the composition for forming the transmittance adjustment layer) 100 parts by weight of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Biscoat #300"), 80 parts by weight of hollow particles ("Thruia 5320" manufactured by JGC Catalysts & Chemicals Ltd., weight average particle diameter: 75 nm), 20 parts by weight of solid particles (silica particles, weight average particle diameter: 12 nm), 10 parts by weight of a photopolymerization initiator (manufactured by BASF SE, trade name: OMNIRAD 2959), and a mixed solvent of MIBK and PGM (MIBK:PGM (weight ratio) = 1:3) were mixed to prepare a composition for forming a transmittance adjustment layer (coating liquid) having a solid content concentration of 3.5% by weight. <2. Manufacture of Substrate and Transmittance Adjustment Layer Laminated Body> The above composition for forming a transmittance adjustment layer was coated on a substrate (polyethylene terephthalate film, manufactured by Mitsubishi Chemical Corporation, thickness 50 μm). A die coater was used for coating. Using a die coater, the above composition for forming a transmittance adjustment layer (coating liquid) was coated on one side of the above PET film to form a coating film. Then, after heating at 80°C for 1 minute, ultraviolet rays with an integrated exposure amount of 200 mJ / cm 2 were irradiated with a high-pressure mercury lamp to manufacture a laminated body composed of a substrate / transmittance adjustment layer. The film thickness of the transmittance adjustment layer was 170 nm. <3. Synthesis of Silver Nanowires and Preparation of Silver Nanowire Dispersion Liquid> In a reaction vessel equipped with a stirrer, at 160°C, 5 ml of anhydrous ethylene glycol and 0.5 ml of an anhydrous ethylene glycol solution of PtCl 2 (concentration: 1.5×10 -4 mol / L) were added. After 4 minutes, to the obtained solution, 2.5 ml of an anhydrous ethylene glycol solution of AgNO 3 (concentration: 0.12 mol / l) and 5 ml of an anhydrous ethylene glycol solution of polyvinylpyrrolidone (MW: 55000) (concentration: 0.36 mol / l) were simultaneously added dropwise over 6 minutes. After this dropwise addition, the mixture was heated to 160°C and reacted for 1 hour or more until AgNO 3 was completely reduced to produce silver nanowires. Next, acetone was added to the reaction mixture containing the silver nanowires obtained as described above until the volume of the reaction mixture became 5 times, and then the reaction mixture was centrifuged (2000 rpm, 20 minutes) to obtain silver nanowires. The obtained silver nanowires had a minor axis diameter of 30 nm to 40 nm, a major axis diameter of 30 nm to 50 nm, and a length of 5 μm to 50 μm. In pure water, the silver nanowires (concentration: 0.2% by weight) and pentaethylene glycol dodecyl ether (concentration: 0.1% by weight) were dispersed to prepare a silver nanowire dispersion I. <4. Production of Transparent Conductive Film> On the opposite surface of the transmittance adjustment layer of the substrate / transmittance adjustment layer laminate, the silver nanowire dispersion I was applied using a die coater so that the resistance value after film formation would be 20 Ω / sq, and then heated at 120 °C for 2 minutes to form a film. Furthermore, 1 part by weight of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Biscoat #300") and 0.1 part by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 907") were diluted with 59 parts by weight of isopropyl alcohol and 25 parts by weight of diacetone alcohol to obtain a monomer composition with a solid content concentration of 1% by weight. This monomer composition was applied to the silver nanowire ink-coated surface using a spin coater so that the dry film thickness would be 70 nm, heated at 80 °C for 1 minute, and then irradiated with ultraviolet light having an integrated exposure amount of 200 mJ / cm 2 to obtain a transparent conductive film. The transparent conductive film obtained as described above was subjected to the above evaluation. The results are shown in Table 1.

[0094] [Example 2] A transparent conductive film was obtained in the same manner as in Example 1, except that the content ratio of the solid particles in the composition for forming the transmittance adjustment layer was 100 parts by weight. The obtained transparent conductive film was subjected to the above evaluation. The results are shown in Table 1.

[0095] [Example 3] A transparent conductive film was obtained in the same manner as in Example 1, except that silica particles with an average particle diameter of 30 nm were used as the solid particles in the composition for forming the transmittance adjustment layer, and the content ratio of the solid particles (silica particles) was 20 parts by weight. The obtained transparent conductive film was subjected to the above evaluation. The results are shown in Table 1.

[0096] [Comparative Example 1] A transparent conductive film was obtained in the same manner as in Example 1, except that no solid particles were added to the composition for forming the transmittance adjustment layer. The obtained transparent conductive film was subjected to the above evaluation. The results are shown in Table 1.

[0097] [Comparative Example 2] A transparent conductive film was obtained in the same manner as in Example 1, except that silica particles having a weight average particle diameter of 100 nm were used as the solid particles in the composition for forming the transmittance adjustment layer, and the content ratio of the solid particles (silica particles) was 20 parts by weight. The obtained transparent conductive film was subjected to the above evaluation. The results are shown in Table 1.

[0098] [Table 1] [Explanation of Reference Numerals]

[0099] 10 Conductive layer 20 Substrate 30 Transmittance adjustment layer 40 Protective layer 100 Transparent conductive film

Claims

1. A conductive layer, a substrate, and a transmittance adjusting layer are provided in this order, The transmittance adjusting layer includes an ultraviolet curable resin, solid particles, and hollow particles, The average particle size of the solid particles is 100% or less of the average particle size of the hollow particles. Transparent conductive film.

2. The transparent conductive film according to claim 1 , wherein the ultraviolet-curable resin is a cured product of a composition for forming a transmittance adjusting layer, the composition containing a polyfunctional monomer.

3. The transparent conductive film according to claim 2 , wherein the composition for forming the transmittance adjusting layer contains a polyfunctional monomer having four or more reactive functional groups.

4. 4. The transparent conductive film according to claim 1, wherein the hollow particles have a weight average particle diameter of 30 nm to 100 nm.

5. 4. The transparent conductive film according to claim 1, wherein a content ratio of the solid particles is 130 parts by weight or less based on 100 parts by weight of the hollow particles.

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