Method for manufacturing a transparent conductive film

Abstract

The present application provides a method for producing a transparent conductive film having small electrically conductive anisotropy even if containing metal nanowires. The method for producing a transparent conductive film of the present application includes: a coating step of forming a coating layer by coating a composition for forming a transparent conductive layer containing metal nanowires on a long substrate while transporting the substrate; and a drying step of drying the coating layer to form a transparent conductive layer on the substrate, the average inclination angle θa of the surface of the substrate being 0.5° or more.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a transparent conductive film. Background Technology

[0002] Previously, in image display devices with touch sensors, the electrodes for the touch sensors were mostly transparent conductive films obtained by forming a metal oxide layer such as ITO (indium tin oxide) on a transparent resin film. However, transparent conductive films with this metal oxide layer are prone to losing conductivity due to bending, making them unsuitable for applications requiring flexibility, such as flexible displays.

[0003] On the other hand, transparent conductive films containing metal nanowires are known as highly flexible transparent conductive films. Metal nanowires are linear conductive materials with a diameter of nanometers. In transparent conductive films composed of metal nanowires, the metal nanowires are mesh-like, thereby forming good electrical conduction paths with a small number of metal nanowires, and openings are formed in the gaps of the mesh, achieving high light transmittance. However, because metal nanowires are linear, they are easily arranged in an oriented state, thus creating the problem of conductive anisotropy in transparent conductive films containing metal nanowires.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2009-505358

[0007] Patent Document 2: Japanese Patent No. 6199034 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The present invention was made to solve the above-mentioned problems, and its object is to provide a method for manufacturing a transparent conductive film with low conductivity anisotropy even when containing metal nanowires.

[0010] means for solving problems

[0011] The method for manufacturing the transparent conductive film of the present invention includes: a coating step in which a transparent conductive layer forming composition comprising metal nanowires is coated on the substrate while transporting the substrate to form a coating layer; and a drying step in which the coating layer is dried to form a transparent conductive layer on the substrate, wherein the average tilt angle θa of the surface of the substrate is 0.5° or more.

[0012] In one embodiment, the average spacing Sm of the unevenness on the surface of the substrate is less than 0.4 mm.

[0013] According to another aspect of the present invention, a transparent conductive film is provided. The transparent conductive film comprises a substrate and a transparent conductive layer disposed on one side of the substrate, wherein the average tilt angle θa of the surface of the substrate is 0.6° or more.

[0014] Invention Effects

[0015] According to the present invention, a method for manufacturing a transparent conductive film with low conductivity anisotropy can be provided. Attached Figure Description

[0016] Figure 1 This is a cross-sectional schematic diagram of a transparent conductive film according to one embodiment of the present invention. Detailed Implementation

[0017] A. Manufacturing method of transparent conductive film

[0018] The method for manufacturing the transparent conductive film of the present invention includes: a coating step, in which a transparent conductive layer forming composition comprising metal nanowires is coated onto a substrate while a strip-shaped substrate is being transported to form a coating layer; and a drying step, in which the coating layer is dried to form a transparent conductive layer on the substrate. Typically, the coating and drying steps are performed while a substrate in a roll is being fed out and transported, forming a transparent conductive layer as described above. Figure 1 The diagram shows a strip-shaped transparent conductive film 100 comprising a substrate 10 and a transparent conductive layer 20 disposed on one side of the substrate 10. In one embodiment, the transparent conductive film is wound after a drying process.

[0019] A-1. Coating process

[0020] As described above, in the coating process, a coating layer is formed by coating a transparent conductive layer forming composition containing metal nanowires onto a long strip substrate while the substrate is being transported.

[0021] (Substrate)

[0022] The average tilt angle θa of the surface of the aforementioned substrate is 0.5° or more. In this invention, by using a substrate with a surface shape specified as described above, metal nanowires are well dispersed in the coating layer. The orientation of these metal nanowires is disordered, resulting in the fabrication of a transparent conductive film with low conductive anisotropy. Furthermore, in this specification, the surface of the substrate refers to the surface on which the coating layer is intended to be formed.

[0023] The average tilt angle θa of the surface of the aforementioned substrate is preferably 0.8° or more, more preferably 1° or more, even more preferably 1.2° or more, and particularly preferably 1.4° or more. If it falls within this range, the effects of the present invention become more significant. The upper limit of the average tilt angle θa is, for example, 3° (preferably 2.5°, more preferably 2°). In this specification, the average tilt angle θa is defined by the following formula (1).

[0024] θa=tan -1 Δa (1)

[0025] In equation (1) above, Δa is, as shown in equation (2) below, a value obtained by dividing the reference length L of the roughness curve specified in JIS B 0601 (1994 edition) by the sum of the differences (height h) between the apex of adjacent peaks and the lowest point of valleys (h1+h2+h3……+hn). The roughness curve described above is a curve from a profile curve from which surface waveform components longer than a specified wavelength have been removed using a phase difference compensation type high-pass filter. Furthermore, the profile curve described above refers to the contour revealed at the cut when the object surface is cut by a plane perpendicular to the object surface.

[0026] Δa=(h1+h2+h3···+hn) / L (2)

[0027] The average spacing Sm of the unevenness on the surface of the aforementioned substrate is preferably 0.4 mm or less, more preferably 0.3 mm or less, even more preferably 0.25 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.15 mm or less. A larger average spacing Sm reduces the orientation of the metal nanowires, enabling the fabrication of a transparent conductive film with particularly low conductivity anisotropy. Furthermore, increasing the average spacing Sm allows for a significant reduction in conductivity anisotropy even with a small average tilt angle θa (e.g., average tilt angle θa = 0.6° to 1°). The lower limit of the average spacing Sm is, for example, 0.03 mm (preferably 0.04 mm). The definition of the average tilt angle θa is based on JIS B 0601 (1994 edition).

[0028] The arithmetic mean surface roughness Ra of the above-mentioned substrate is preferably 0.05 μm to 3 μm, more preferably 0.1 μm to 1.5 μm. Within this range, a transparent conductive film with particularly small conductive anisotropy can be manufactured. The definition of arithmetic mean surface roughness Ra is based on JIS B 0601 (1994 edition).

[0029] The thickness of the above-mentioned substrate is preferably 20μm to 200μm, more preferably 30μm to 150μm.

[0030] The total light transmittance of the above-mentioned substrate is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more.

[0031] The material constituting the above-mentioned substrate can be any suitable material. Specifically, for example, polymeric substrates such as films and plastic substrates are preferred. This is because the substrate has excellent smoothness and wettability to the composition for forming the transparent conductive layer, and productivity can be greatly improved through continuous production using rollers.

[0032] The materials constituting the aforementioned substrate are typically polymer films with thermoplastic resins as the main component. Examples of thermoplastic resins include polyester resins, cycloalkenyl resins such as polynorbornene, acrylic resins, polycarbonate resins, and cellulose resins. Polyester resins, cycloalkenyl resins, or acrylic resins are preferred. These resins exhibit excellent transparency, mechanical strength, thermal stability, and moisture barrier properties. The aforementioned thermoplastic resins can be used alone or in combination of two or more. Additionally, optical films used for polarizers, such as low-phase-difference substrates, high-phase-difference substrates, phase-difference plates, and brightness-enhancing films, can also be used as substrates.

[0033] The method of conveying the substrate can be any suitable method. For example, conveying using conveyor rollers, conveying using conveyor belts, or combinations thereof can be cited. The conveying speed is, for example, 5 m / min to 50 m / min.

[0034] (Metal nanowires)

[0035] Metal nanowires are conductive materials made of metal, with needle-like or filamentous shapes and a diameter of nanometers. Metal nanowires can be straight or curved. When using a transparent conductive layer composed of metal nanowires, by making the nanowires mesh-like, even a small amount of nanowires can form good electrical conduction paths, resulting in a transparent conductive film with low resistance. Furthermore, by making the metal nanowires mesh-like, openings can be formed in the gaps between the meshes, resulting in a transparent conductive film with high light transmittance.

[0036] The ratio of the thickness d to the length L of the aforementioned metal nanowires (aspect ratio: L / d) is preferably 10 to 100,000, more preferably 50 to 100,000, and particularly preferably 100 to 10,000. Using metal nanowires with such a large aspect ratio allows for good interlacing, enabling high conductivity with a small amount of metal nanowires. As a result, a transparent conductive film with high light transmittance can be obtained. Furthermore, in this specification, "thickness of the metal nanowire" refers to its diameter when the cross-section of the metal nanowire is circular, its minor axis when it is elliptical, and its longest diagonal when it is polygonal. The thickness and length of the metal nanowires can be confirmed using a scanning electron microscope or a transmission electron microscope.

[0037] The thickness of the aforementioned metal nanowires 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. Within this range, a transparent conductive layer with high light transmittance can be formed.

[0038] The length of the aforementioned metal nanowires is preferably 1 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 10 μm to 100 μm. Within this range, a transparent conductive film with high conductivity can be obtained. Furthermore, if the length of the metal nanowires is within the aforementioned range, the effect obtained by the specific surface shape of the substrate as described above is amplified.

[0039] As the metal constituting the aforementioned metal nanowires, any suitable metal can be used, as long as it is a conductive metal. Examples of metals constituting the aforementioned metal nanowires include silver, gold, copper, and nickel. Alternatively, materials obtained by plating these metals (e.g., gold plating) can also be used. From the viewpoint of conductivity, silver, copper, or gold are preferred, with silver being more preferred.

[0040] As a method for manufacturing the aforementioned metal nanowires, any suitable method can be employed. Examples include the method of reducing silver nitrate in solution; and the method of applying voltage or current to the precursor surface from the tip of a probe, drawing out metal nanowires from the tip of the probe, and continuously forming the metal nanowires. In the method of reducing silver nitrate in solution, silver salts such as silver nitrate can be reduced in the liquid phase in the presence of polyols such as ethylene glycol and polyvinylpyrrolidone, thereby synthesizing silver nanowires. Uniformly 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.

[0041] (Composition for forming a transparent conductive layer)

[0042] The composition for forming a transparent conductive layer includes metal nanowires. In one embodiment, the composition for forming a transparent conductive layer is prepared by dispersing the metal nanowires in any suitable solvent. Examples of such solvents include water, alcohol-based solvents, ketone-based solvents, ether-based solvents, hydrocarbon-based solvents, and aromatic solvents. Furthermore, the composition for forming a transparent conductive layer may further include additives such as conductive materials (e.g., conductive particles) other than resins (adhesive resins) and metal nanowires, and leveling agents. Additionally, the composition for forming a transparent conductive layer may also include additives such as plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, thickeners, inorganic particles, surfactants, and dispersants.

[0043] The viscosity of the composition for forming the transparent conductive layer is preferably 5 mP·s / 25°C to 300 mP·s / 25°C, more preferably 10 mP·s / 25°C to 100 mP·s / 25°C. Within this range, the effect obtained by the specific surface shape of the substrate as described above is amplified. The viscosity of the composition for forming the transparent conductive layer can be measured using a rheometer (e.g., Anton Paar's MCR302).

[0044] The dispersion concentration of the metal nanowires in the composition for forming the transparent conductive layer is preferably 0.01% to 5% by weight. Within this range, the effects of the present invention become significant.

[0045] As a coating method for the above-mentioned composition for forming a transparent conductive layer, any suitable method can be used. Examples of coating methods include: spraying, bar coating, roller coating, die coating, inkjet coating, screen coating, dip coating, letterpress printing, gravure printing, photogravure printing, etc.

[0046] The preferred weight per unit area of ​​the above coating layer is 0.3 g / m². 2 ~30g / m 2 More preferably 1.6 g / m 2 ~16g / m 2 If the range is such, the effect obtained by the specific surface shape of the substrate as described above becomes greater.

[0047] The film thickness of the above-mentioned coating layer is preferably 1μm to 50μm, and more preferably 2μm to 40μm.

[0048] A-2. Drying process

[0049] As described above, in the drying process, the coating layer is dried to form a transparent conductive layer on the substrate.

[0050] As a drying method for the coating layer, any suitable drying method can be used (e.g., natural drying, air drying, heat drying). For example, in the case of heat drying, the drying temperature is typically 80°C to 150°C, and the drying time is typically 1 to 20 minutes.

[0051] Any appropriate treatment can be performed after the drying process. For example, when using a composition for forming a transparent conductive layer containing an adhesive resin, a curing treatment using ultraviolet irradiation or the like can be performed.

[0052] B. Transparent conductive film

[0053] A transparent conductive film is formed using the manufacturing method described above. Figure 1 This is a cross-sectional schematic diagram of a transparent conductive film according to one embodiment of the present invention. The transparent conductive film 100 includes: a substrate 10, and a transparent conductive layer 20 disposed on one side of the substrate 10.

[0054] The surface resistivity of the transparent conductive film is preferably 0.1 Ω / □ to 1000 Ω / □, more preferably 0.5 Ω / □ to 300 Ω / □, and particularly preferably 1 Ω / □ to 200 Ω / □. The ratio of the surface resistivity on the TD (direction orthogonal to MD) to the surface resistivity on the MD (transport direction) (TD / MD) of the transparent conductive film is preferably 0.7 to 1.5, more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1. The surface resistivity can be measured using the "Automatic Resistivity Measurement System MCP-S620 / MCP-S521" from MITSUBISHI CHEMICAL ANALYTECH.

[0055] The haze value of the above-mentioned transparent conductive film is preferably 20% or less, more preferably 10% or less, and even more preferably 0.1% to 5%.

[0056] The total light transmittance of the above-mentioned transparent conductive film is preferably 30% or more, more preferably 35%, and particularly preferably 40% or more.

[0057] The average tilt angle θa of the surface of the aforementioned substrate is 0.6° or more, preferably 0.8° or more, more preferably 1° or more, even more preferably 1.2° or more, and particularly preferably 1.4° or more. If it falls within this range, the effects of the present invention become more significant. The upper limit of the average tilt angle θa is, for example, 3° (preferably 2.5°, more preferably 2°). Furthermore, the aforementioned average tilt angle θa of the substrate surface is measured before the formation of the transparent conductive layer.

[0058] The average spacing Sm of the unevenness on the surface of the substrate is preferably 0.4 mm or less, more preferably 0.3 mm or less, even more preferably 0.25 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.15 mm or less. Furthermore, the average spacing Sm of the unevenness on the surface of the substrate is measured before the transparent conductive layer is formed.

[0059] The arithmetic mean surface roughness Ra of the substrate surface is preferably 0.05 μm to 3 μm, more preferably 0.1 μm to 1.5 μm. Furthermore, the arithmetic mean surface roughness Ra of the substrate surface is measured before the formation of the transparent conductive layer.

[0060] The preferred weight per unit area of ​​the transparent conductive layer is 0.001 g / m². 2 ~0.09g / m 2 More preferably, it is 0.005 g / m 2 ~0.05g / m 2 .

[0061] The proportion of metal nanowires in the aforementioned transparent conductive layer is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, relative to 100 parts by weight of the adhesive resin constituting the transparent conductive layer. Within this range, a transparent conductive film with excellent conductivity and light transmittance can be obtained.

[0062] Example

[0063] The present invention will be specifically described below through examples, but the present invention is not limited to these examples. The evaluation method of the examples is as follows. Furthermore, regarding the thickness, after embedding with epoxy resin, a cross-section was formed by cutting using an ultrathin slicer, and the thickness was measured using a scanning electron microscope "S-4800" manufactured by Hitachi High-Tech Corporation.

[0064] (1) Shape of the substrate surface

[0065] According to JIS B0601 (1994 edition), the average inter-concave-convex distance Sm (mm) and the arithmetic mean surface roughness Ra (μm) were measured. Specifically, a sample was prepared by bonding a glass plate (MATSUNAMI, MICRO SLIDE GLASS, product number S, thickness 1.3 mm, 45 × 50 mm) to the side opposite to the measurement surface using an adhesive. Using a stylus-type surface roughness measuring instrument (Kosaka Research Institute Co., Ltd., high-precision fine shape measuring instrument, trade name "SURFCODER ET4000") with a measuring needle having a radius of curvature R = 2 μm at the tip (diamond), the surface shape of the anti-glare layer of the above sample was measured in a certain direction under the conditions of a scanning speed of 0.1 mm / s, a cutoff value of 0.8 mm, and a measurement length of 4 mm. The average inter-concave-convex distance Sm was calculated, and the average tilt angle θa (°) was calculated from the obtained surface roughness curve.

[0066] (2) Surface resistivity

[0067] The surface resistance values ​​(MD and TD values) of transparent conductive films were measured using a non-contact surface resistance meter manufactured by NAPSON Corporation, trade name "EC-80", via the eddy current method. The measurement temperature was set to 23°C.

[0068] [Manufacturing Example 1] Preparation of a composition for forming a transparent conductive layer

[0069] Silver nanowires were synthesized using the method described in Chem. Mater. 2002, 14, 4736-4745.

[0070] The silver nanowires obtained above were dispersed in pure water at a concentration of 0.2% by weight and dodecyl pentaethylene glycol at a concentration of 0.1% by weight to obtain a composition for forming a transparent conductive layer.

[0071] [Example 1]

[0072] A coating solution containing 100 parts by weight of acrylic monomer (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat#300", solid content 56% by weight), 30 parts by weight of particles (manufactured by Sekisui Kasei Co., Ltd., trade name "TECHPOLYMER SSX-105"), 0.5 parts by weight of initiator (manufactured by BASF, trade name "Irgacure127"), and 35 parts by weight of butyl acetate was coated onto a PET film (TORAY Co., Ltd., trade name "U40", thickness: 23 μm). The coating was dried at 100°C for 2 minutes and then irradiated with 300 mJ of ultraviolet light to form substrate A (thickness: 20 μm) on the PET film.

[0073] On substrate A, which had been peeled from the PET film, the transparent conductive layer forming composition prepared in Manufacturing Example 1 was applied using a bar coater (manufactured by Daiichi Riko Co., Ltd., product name "Bar Coater No. 16"). The mixture was dried in a blower dryer at 120°C for 2 minutes to form a transparent conductive layer, thus obtaining a transparent conductive film having both a substrate and a transparent conductive layer. Furthermore, the average tilt angle θa of the surface of substrate A where the transparent conductive layer is formed is 1.5°, and the average spacing Sm between the uneven surfaces is 0.05 mm.

[0074] The obtained transparent conductive film was used for the above evaluation (2). The results are shown in Table 1.

[0075] [Example 2]

[0076] Five parts by weight of particles (manufactured by Sogen Chemical Industries, trade name "SX-350H") were used to replace 30 parts by weight of particles (manufactured by Sekisui Kasei Corporation, trade name "TECHPOLYMER SSX-105"), and 0.2 parts by weight of a thixotropic agent (manufactured by Kunimitsu Kogyo Co., Ltd., trade name "SAN") were added to the coating solution. Otherwise, the same procedure as in Example 1 was followed to form substrate B (thickness: 20 μm). Then, a transparent conductive layer was formed using the same method as in Example 1, resulting in a transparent conductive film having a substrate and a transparent conductive layer. Furthermore, the average tilt angle θa of the surface of substrate D where the transparent conductive layer is formed is 0.9°, and the average spacing Sm between the uneven surfaces is 0.15 mm.

[0077] The obtained transparent conductive film was used for the above evaluation (2). The results are shown in Table 1.

[0078] [Example 3]

[0079] Except that the amount of particles (manufactured by Sogen Chemical Industries, trade name "SX-350H") added was set to 10 parts by weight, the same procedure as in Example 2 was followed to form substrate C (thickness: 20 μm). Then, a transparent conductive layer was formed using the same method as in Example 1, and a transparent conductive film having a substrate and a transparent conductive layer was obtained. Furthermore, the average tilt angle θa of the surface of substrate C where the transparent conductive layer is formed is 1.5°, and the average spacing Sm between the uneven surfaces is 0.12 mm.

[0080] The obtained transparent conductive film was used for the above evaluation (2). The results are shown in Table 1.

[0081] [Comparative Example 1]

[0082] Except that a PET film (manufactured by TORAY, trade name "U40", thickness: 23 μm, average tilt angle: 0.1°, average unevenness spacing Sm: 0.04 mm) was used as substrate B instead of substrate A, the procedure was the same as in Example 1 to obtain a transparent conductive film. The obtained transparent conductive film was submitted for the evaluation described above (2). The results are shown in Table 1.

[0083] [Comparative Example 2]

[0084] Except that 15 parts by weight of particles (manufactured by Sekisui Kasei Corporation, trade name "TECHNOPOLYMER SSX-101") were used instead of 30 parts by weight of particles (manufactured by Sekisui Kasei Corporation, trade name "TECHPOLYMER SSX-105"), the same procedure as in Example 1 was followed to form substrate D (thickness: 20 μm). Then, a transparent conductive layer was formed using the same method as in Example 1, resulting in a transparent conductive film having both a substrate and a transparent conductive layer. Furthermore, the average tilt angle θa of the surface of substrate D where the transparent conductive layer is formed is 0.3°, and the average spacing Sm between the uneven surfaces is 0.19 mm.

[0085] The obtained transparent conductive film was used for the above evaluation (2). The results are shown in Table 1.

[0086] Table 1

[0087]

[0088] [Reference Example 1]

[0089] A coating solution containing 100 parts by weight of acrylic monomer (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat#300", solid content 56% by weight), 10 parts by weight of particles (manufactured by Sekisui Kasei Co., Ltd., trade name "TECHPOLYMER SSX-101"), 0.5 parts by weight of initiator (manufactured by BASF, trade name "Irgacure 127"), and 35 parts by weight of butyl acetate was coated onto a PET film. The coating was dried at 100°C for 2 minutes and then irradiated with 300 mJ of ultraviolet light to form substrate C (thickness: 20 μm) on the PET film.

[0090] On the substrate C, which had been peeled off from the PET film, the composition for forming the transparent conductive layer prepared in Manufacturing Example 1 was coated using a bar coater (manufactured by Daiichi Riko Co., Ltd., product name "Bar Coater No. 16"). The coating was then dried in a blower dryer at 120°C for 2 minutes to form a transparent conductive layer, thus obtaining a transparent conductive film having both a substrate and a transparent conductive layer. Furthermore, the average tilt angle θa of the surface of substrate C where the transparent conductive layer is formed is 0.1°, and the average spacing Sm between the uneven surfaces is 0.27 mm.

[0091] The obtained transparent conductive films were subjected to the above evaluation (2), and the surface resistance of MD was 41Ω and that of TD was 62Ω.

[0092] Symbol Explanation

[0093] 10 Substrate

[0094] 20 Transparent conductive layer

[0095] 100 Transparent Conductive Film

Claims

1. A method for producing a transparent conductive film, comprising: a coating step of forming a coating layer by coating a composition for forming a transparent conductive layer containing metal nanowires on a long substrate while conveying the substrate; and a drying step of drying the coating layer to form a transparent conductive layer on the substrate, an average inclination angle θa of a surface of the substrate defined by the following formula (1) is 1.2° or more and 3° or less: θa = tan -1 Δa (1) In the formula (1), Δa is a value obtained by dividing a sum (h1+h2+h3+...+hn) of differences (heights h) between adjacent peak apexes and valley bottoms in a reference length L of a roughness curve prescribed in JIS B 0601 (1994 edition) by the reference length L; the roughness curve is a curve in which surface wave components longer than a prescribed wavelength are removed from a cross-sectional curve using a phase difference compensation type high-pass filter; and the cross-sectional curve refers to a profile appearing at a cut of an object surface when the object surface is cut in a plane at right angles to the object surface. Δa = (h1+h2+h3+...+hn) / L (2).

2. The method for producing a transparent conductive film according to claim 1, wherein an average interval Sm of irregularities of the surface of the substrate is 0.4 mm or less.

3. A transparent conductive film provided with a substrate and a transparent conductive layer containing metal nanowires disposed on one side of the substrate, an average inclination angle θa of a surface of the substrate defined by the following formula (1) is 1.2° or more and 3° or less: θa = tan -1 Δa (1) In the formula (1), Δa is a value obtained by dividing a sum (h1+h2+h3+...+hn) of differences (heights h) between adjacent peak apexes and valley bottoms in a reference length L of a roughness curve prescribed in JIS B 0601 (1994 edition) by the reference length L; the roughness curve is a curve in which surface wave components longer than a prescribed wavelength are removed from a cross-sectional curve using a phase difference compensation type high-pass filter; and the cross-sectional curve refers to a profile appearing at a cut of an object surface when the object surface is cut in a plane at right angles to the object surface. Δa = (h1+h2+h3+...+hn) / L (2).

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