Transparent conductive film

Abstract

Provided is a transparent conductive film which, when used in an anti-fog cover, electromagnetic wave shielding, etc. of a display, touch panel, camera, etc. that need to be formed into a three-dimensional shape, has excellent characteristics in terms of each of the total light transmittance, surface resistance, and elongation rate having conductivity based on molding processing. A transparent conductive film has a transparent plastic film substrate and a transparent metal oxide layer, and sequentially has a metal nanowire layer and a transparent metal oxide layer on at least one side of the transparent plastic film substrate. The total light transmittance (JIS-K7361-1) of the transparent conductive film is 75% or more and 95% or less, the surface resistance value of the transparent conductive film is 1 to 150 Ω / square, and when stretched in the range of +10% or more and +200% or less with respect to the length of the unstretched transparent conductive film, it has conductivity.

Description

Technical Field

[0001] The present invention relates to a transparent conductive film having a metal nanowire layer and a transparent metal oxide layer in sequence on a transparent plastic film substrate, and particularly to a transparent conductive film having excellent transparency, conductivity, moldability, and environmental stability required for use in a transparent anti-fog film, a three-dimensional touch panel, and electromagnetic wave shielding. Background Art

[0002] A transparent conductive film formed by laminating a transparent and low-resistance film on a transparent plastic film substrate is widely used in applications in the electrical / electronic field, such as a transparent electrode for a flat panel display such as a liquid crystal display or an electroluminescence (EL) display, a touch panel, an anti-fog film, and electromagnetic wave shielding, by utilizing its conductivity.

[0003] As a transparent conductive film having excellent transparency, conductivity, and environmental stability, for example, a transparent conductive film in which a transparent metal oxide film of indium-tin composite oxide is laminated on a transparent plastic film substrate is generally produced (for example, Patent Document 1).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-115014 Summary of the Invention

[0007] -Problems to be Solved by the Invention-

[0008] In recent years, in applications such as anti-fog covers for displays, touch panels, cameras, and electromagnetic wave shielding, the demand for realizing three-dimensional shapes based on mold forming or the like has increased from the viewpoint of designability and the like. In order to realize a three-dimensional shape, in addition to transparency, conductivity, and environmental stability, moldability is also required to be excellent as a characteristic of the transparent conductive film. However, at present, it is very difficult to industrially manufacture such a transparent conductive film.

[0009] The conventional transparent conductive film shown in Patent Document 1 has excellent transparency, conductivity, and environmental stability. However, when the conventional transparent conductive film is stretched as a moldability test, when the stretching with respect to the initial length is less than +10%, that is, when it hardly stretches, the transparent conductive film loses its conductivity and the moldability is insufficient.

[0010] An object of the present invention is to provide a transparent conductive film having excellent transparency, conductivity, moldability, and environmental stability in view of the above-mentioned conventional problems.

[0011] -Means for Solving the Problems-

[0012] The present invention has been completed in view of the above circumstances, and the transparent conductive film of the present invention that can solve the above problems has the following structure.

[0013] 1. A transparent conductive film having a transparent plastic film substrate and a transparent metal oxide layer,

[0014] having a metal nanowire layer and a transparent metal oxide layer in sequence on at least one side of the transparent plastic film substrate,

[0015] the total light transmittance (JIS-K 7361-1) of the transparent conductive film is 75% or more and 95% or less, the surface resistance value of the transparent conductive film is 1 to 150 Ω / sq, and

[0016] when stretched in the range of +10% or more and +200% or less with respect to the length of the unstretched transparent conductive film, it has conductivity.

[0017] 2. According to the above transparent conductive film,

[0018] the surface resistance value of the transparent conductive film under the condition of being treated at 60 °C and 95% RH for 240 hours and the surface resistance value of the transparent conductive film under the condition of being treated at 85 °C and 85% RH for 240 hours are respectively 0.5 times or more and 1.5 times or less with respect to the surface resistance value of the transparent conductive film before the above heat treatment.

[0019] 3. According to the above transparent conductive film,

[0020] the surface resistance value of the transparent conductive film under the condition of being treated at 90 °C for 240 hours is respectively 0.5 times or more and 1.5 times or less with respect to the surface resistance value of the transparent conductive film before the above heat treatment.

[0021] 4. According to the above transparent conductive film, it is configured such that the transparent metal oxide layer covers at least a part of the metal nanowire layer and then adheres to the transparent plastic film substrate, the thickness of the metal nanowire layer is 0.10 to 1.00 μm, and further the thickness of the transparent metal oxide layer measured by fluorescent X-ray is 2 to 30 nm.

[0022] 5. According to the above transparent conductive film, the transparent metal oxide is indium-tin composite oxide, and the concentration of tin oxide contained in the transparent metal oxide layer is 8% by mass or more and 50% by mass or less.

[0023] 6. According to the above transparent conductive film, the diameter of the metal nanowire is 2 to 80 nm, and the length of the metal nanowire is 10 to 100 μm.

[0024] 7. The transparent conductive film described above has a curable resin layer on the opposite side of the surface of the transparent plastic film substrate on which the metal nanowire layer is laminated.

[0025] 8. The transparent conductive film described above further has a functional layer between the transparent plastic film substrate and the metal nanowire layer.

[0026] 9. The metal nanowire layer of the transparent conductive film described above has voids.

[0027] - Effects of the Invention -

[0028] According to the present invention, it is possible to provide a transparent conductive film having excellent characteristics in terms of transparency, conductivity, moldability, and environmental stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram showing the structure of one embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram for explaining the position of the center roll as an example of the sputtering apparatus preferably used in the present invention.

[0031] Figure 3 It is a schematic diagram of the metal nanowire layer in one embodiment of the present invention.

[0032] Figure 4 It is a schematic diagram showing the moldability test. DETAILED DESCRIPTION OF THE INVENTION

[0033] The transparent conductive film of the present invention is a transparent conductive film having a metal nanowire layer and a transparent metal oxide layer in this order on at least one side of a transparent plastic film substrate. The total light transmittance (JIS-K7361-1) of the transparent conductive film is 75% or more and 95% or less, the surface resistance value of the transparent conductive film is 1 to 150 Ω / square, and further, when stretched in the range of +10% or more and +200% or less with respect to the length of the unstretched transparent conductive film, it has conductivity.

[0034] The transparent conductive film of the present invention adopts a structure having a metal nanowire layer and a transparent metal oxide layer in this order on at least one side of a transparent plastic film substrate, thereby realizing a transparent conductive film having excellent characteristics in terms of transparency, conductivity, moldability, and environmental stability.

[0035] In the use of the transparent conductive film of the present invention, due to the need for excellent visual recognition, the total light transmittance (JIS-K7361-1) of the transparent conductive film of the present invention is 75% or more and 95% or less. The higher the total light transmittance, the more preferable, so it is preferably 80% or more and 95% or less. More preferably, it is 85% or more and 95% or less.

[0036] The surface resistance value of the transparent conductive film of the present invention is 1 Ω / square or more and 150 Ω / square or less. In the use of the transparent conductive film of the present invention, if the surface resistance value is 150 Ω / square or less, excellent characteristics are exhibited. Regarding excellent characteristics, for example, if it is an anti-fog film, anti-fogging property can be cited, and if it is an electromagnetic wave shield, electromagnetic wave shielding property can be cited, etc. It is preferably 100 Ω / square or less. More preferably, it is 80 Ω / square or less.

[0037] There is a trade-off relationship between the surface resistance value and transparency. Therefore, within the industrially possible range, the surface resistance value with transparency is 1 Ω / square or more. For example, it can be 5 Ω / square or more, or it can be 10 Ω / square or more.

[0038] The transparent conductive film of the present invention has conductivity when stretched in the range of +10% or more and +200% or less with respect to the length of the unstretched transparent conductive film. In the present invention, the term "unstretched transparent conductive film" for the above-mentioned stretching means the state of the transparent conductive film before the molding processability test. In addition, hereinafter, in the present invention, the length of the unstretched transparent conductive film may sometimes be simply referred to as the initial length.

[0039] If it has conductivity during stretching of +10% or more with respect to the length of the unstretched transparent conductive film, excellent characteristics can be exhibited even during three-dimensional processing, so it is preferable. The shape obtained by three-dimensional processing is not particularly limited. For example, it can be a shape having a hemispherical, elliptical, arc-shaped form, a cuboid, a cube, etc. For example, in the anti-fog covers, electromagnetic wave shielding, etc. of displays, touch panels, cameras, etc., it can be formed into a three-dimensional shape for use. Of course, the transparent conductive film of the present invention can also be used in a planar shape as in the past.

[0040] According to the present invention, not only is such excellent three-dimensional processability, for example, if it is an anti-fog film, anti-fogging property can also be exhibited, and if it is an electromagnetic wave shield, electromagnetic wave shielding property can also be exhibited, etc.

[0041] With respect to the length of the unstretched transparent conductive film, it preferably has conductivity during stretching of +30% or more, for example +50% or more, and in one embodiment +80% or more. More preferably, it is +100% or more. Since the stretching rate with conductivity and transparency are in a trade-off relationship, in order to achieve a balance with transparency, it is preferably suppressed to a stretching of +200% or less. In addition, as described later, if the resistance value after stretching is 40 MΩ or less, it can be determined that there is conductivity.

[0042] The transparent conductive film of the present invention is a transparent conductive film having a metal nanowire layer and a transparent metal oxide layer in sequence on at least one side of a transparent plastic film substrate. The surface resistance value of the transparent conductive film under the condition of 60°C 95% RH for 240 hours and the surface resistance value of the transparent conductive film under the condition of 85°C 85% RH for 240 hours are respectively 0.5 times or more and 1.5 times or less with respect to the surface resistance value of the transparent conductive film before the above heat treatment.

[0043] For the transparent conductive film of the present invention, it is preferred that the surface resistance values of the transparent conductive film after being treated at 60°C 95% RH for 240 hours and the transparent conductive film after being treated at 85°C 85% RH for 240 hours are respectively 0.5 times or more and 1.5 times or less with respect to the initial surface resistance value.

[0044] If the surface resistance values of the transparent conductive film after being treated at 60°C 95% RH for 240 hours and the transparent conductive film after being treated at 85°C 85% RH for 240 hours are respectively 0.5 times or more and 1.5 times or less with respect to the initial surface resistance value, even in a harsh environment such as a closed space, for example, inside a vehicle, when the temperature and humidity are high during the rainy season, etc., excellent characteristics are maintained, so it is preferred. Regarding excellent characteristics, for example, if it is an anti-fog film, anti-fogging property can be cited, and if it is an electromagnetic wave shielding film, electromagnetic wave shielding property can be cited, etc.

[0045] In one mode, after the transparent conductive film is treated at 60°C and 95% RH for 240 hours and then at 85°C and 85% RH for 240 hours, the surface resistance value of each surface of the transparent conductive film relative to the initial surface resistance value is 1.5 times or less, can be 1.3 times or less, and preferably 1.2 times or less. In addition, after the transparent conductive film is treated at 60°C and 95% RH for 240 hours and then at 85°C and 85% RH for 240 hours, the surface resistance value of each surface of the transparent conductive film relative to the initial surface resistance value is 0.5 times or more, can be 0.7 times or more, and preferably 0.8 times or more. In one mode, these upper and lower limits can also be appropriately combined. After the transparent conductive film is treated at 60°C and 95% RH for 240 hours and then at 85°C and 85% RH for 240 hours, the surface resistance value of each surface of the transparent conductive film relative to the initial surface resistance value is within the above range, so that excellent characteristics can be maintained even in a harsh environment of high temperature / high humidity, which is therefore preferred. Regarding excellent characteristics, for example, if it is an anti-fog film, anti-fogging property can be cited, and if it is electromagnetic wave shielding, electromagnetic wave shielding property can be cited, etc.

[0046] The transparent conductive film of the present invention is a transparent conductive film having a metal nanowire layer and a transparent metal oxide layer in sequence on at least one side of a transparent plastic film substrate. The surface resistance value of the transparent conductive film under the condition of being treated at 90°C for 240 hours is 0.5 times or more and 1.5 times or less relative to the surface resistance value of the transparent conductive film before the above heat treatment.

[0047] For the transparent conductive film of the present invention, it is preferred that the surface resistance value of the transparent conductive film after being treated at 90°C for 240 hours is 0.5 times or more and 1.5 times or less relative to the initial surface resistance value.

[0048] If the surface resistance value of the transparent conductive film after being treated at 90°C for 240 hours is 0.5 times or more and 1.5 times or less relative to the initial surface resistance value, excellent characteristics can be maintained even in a very high temperature environment such as in summer and in a harsh environment such as inside a closed space, for example, inside a vehicle, which is therefore preferred. Regarding excellent characteristics, for example, if it is an anti-fog film, anti-fogging property can be cited, and if it is electromagnetic wave shielding, electromagnetic wave shielding property can be cited, etc.

[0049] In one mode, the surface resistance value of the transparent conductive film after being treated at 90 °C for 240 hours is 1.5 times or less, preferably 1.3 times or less, more preferably 1.2 times or less, relative to the initial surface resistance value. In addition, the surface resistance value of the transparent conductive film after being treated at 90 °C for 240 hours is 0.5 times or more, preferably 0.7 times or more, more preferably 0.8 times or more, relative to the initial surface resistance value. In one mode, these upper and lower limits can be appropriately combined. By making the surface resistance value of the transparent conductive film after being treated at 90 °C for 240 hours fall within the above range relative to the initial surface resistance value, excellent characteristics can be maintained even in a harsh high-temperature environment, which is therefore preferred. Regarding excellent characteristics, for example, in the case of an anti-fog film, anti-fogging property can be cited, and in the case of electromagnetic wave shielding, electromagnetic wave shielding property can be cited, etc.

[0050] The transparent conductive film of the present invention is the above-mentioned transparent conductive film, which is configured such that the transparent metal oxide layer covers at least a part of the metal nanowire layer and is further attached to the transparent plastic film substrate. The thickness of the metal nanowire layer is 0.10 to 1.00 μm, and the thickness of the transparent metal oxide layer measured by fluorescent X-ray is 2 to 30 nm.

[0051] Regarding the transparent conductive film, in order to achieve excellent characteristics in terms of transparency, conductivity, moldability, and environmental stability, in-depth research has been repeatedly conducted, and as a result, the following structure is preferably adopted, which is configured such that the transparent metal oxide layer covers at least a part of the metal nanowire layer and is further attached to the transparent plastic film substrate. In Figure 1 An example of the structure is shown. In Figure 1 As shown in the figure, a metal nanowire layer 2 and a transparent metal oxide layer 3 are disposed on a transparent plastic film 1. The transparent metal oxide layer 3 is configured to cover at least a part of the metal nanowire layer 2 and is attached to the transparent plastic film substrate 1.

[0052] Here, for the sake of illustration, Figure 1 is a diagram schematically showing a part of the metal nanowire layer, and illustrates the relationship between the metal nanowires in the metal nanowire layer and the transparent metal oxide layer.

[0053] In one mode, the metal nanowires contained in the metal nanowire layer can be regularly arranged or randomly arranged. In addition, the number of metal nanowires contained in the metal nanowire layer is not limited to 1, and can include multiple ones. In addition, in the metal nanowire layer, the metal nanowires can be arranged in a plane or configured three-dimensionally. In addition, it can also be a regular or random arrangement.

[0054] For example, in the transparent conductive film of the present invention, voids may also exist in the metal nanowire layer on the transparent plastic film substrate, and the transparent metal oxide layer is attached to the transparent plastic film substrate with the metal nanowires and voids therebetween.

[0055] For example, the metal nanowire layer may also have voids within the layer, and at least a part of the voids is configured in a state where a transparent metal oxide layer is present.

[0056] By providing voids in the metal nanowire layer, excellent formability can be exhibited. Furthermore, since a plurality of voids can be provided in the metal nanowire layer, the effects caused by heat and humidity can be alleviated, and excellent environmental stability can be exhibited.

[0057] In one aspect, in the structure of the transparent conductive film of the present invention, the metal nanowires and the transparent plastic film substrate are covered with a transparent metal oxide layer.

[0058] Here, it can be inferred that when stretching is performed by molding, a force for peeling the transparent plastic film substrate and the metal nanowires acts. According to the present invention, since the transparent metal oxide layer covers across both the metal nanowires and the transparent plastic film substrate, the transparent metal oxide layer can suppress the peeling of the metal nanowires from the transparent plastic film substrate. Therefore, it is considered that the transparent conductive film of the present invention has conductivity even at a high stretching rate.

[0059] Although it should not be construed as being limited to a specific theory, during stretching based on molding, the transparent metal oxide layer moderately forms cracks during stretching of about 2%, thereby releasing the force applied to the transparent metal oxide layer. In addition, since the transparent metal oxide layer does not peel off from the transparent plastic film substrate and the metal nanowire layer and is in sufficient close contact, the force during stretching is released by the synergistic effect of the transparent metal oxide layer and the metal nanowire layer with the transparent plastic film substrate. Moreover, the transparent metal oxide layer can suppress the peeling of the metal nanowires from the transparent plastic film substrate.

[0060] In addition, even if only the metal nanowire layer is attached to one surface of the transparent plastic film substrate and only the transparent metal oxide layer is attached, since it does not have conductivity at a high stretching rate as in the transparent conductive film of the present invention, the metal nanowire layer and the transparent metal oxide layer are sequentially provided on at least one surface side of the transparent plastic film substrate, and further, the transparent metal oxide layer is configured to cover at least a part of the metal nanowire layer and then attached to the transparent plastic film substrate, whereby initially excellent formability can be exhibited.

[0061] Furthermore, a structure in which a transparent metal oxide layer is configured to cover at least a part of the metal nanowire layer and then adhere to the transparent plastic film substrate has excellent environmental stability. Generally, as the metal nanowire, silver nanowire or copper nanowire is used. Therefore, if environmental tests such as 60 °C, 95% RH, 85 °C, 85% RH, 90 °C are carried out, the oxidation of metals such as silver and copper progresses, and the surface resistance value is likely to increase. In the case of the structure of the transparent conductive film of the present invention, since the metal nanowire is covered with a transparent metal oxide layer having excellent environmental stability, the surface resistance value is hardly increased even when an environmental test is carried out. Therefore, it is preferable.

[0062] The thickness of the metal nanowire layer of the transparent conductive film of the present invention is preferably 0.10 to 1.00 μm. If the thickness of the metal nanowire layer is 0.10 μm or more, the elongation at break and conductivity based on molding processing are excellent, so it is preferable. It is preferably 0.15 μm or more. More preferably, it is 0.20 μm or more. If the thickness of the metal nanowire layer is 1.00 μm or less, the transparency is excellent, so it is preferable. It is preferably 0.90 μm or less. More preferably, it is 0.80 μm or less.

[0063] In the transparent conductive film of the present invention, the thickness of the transparent metal oxide layer measured by fluorescent X-ray is preferably 2 to 30 nm. If the thickness of the transparent metal oxide layer measured by fluorescent X-ray is 2 nm or more, the elongation at break and environmental stability based on molding processing are excellent, so it is preferable. It is preferably 3 nm or more. More preferably, it is 5 nm or more. If the thickness of the transparent metal oxide layer measured by fluorescent X-ray is 30 nm or less, the elongation at break and transparency based on molding processing are excellent, so it is preferable. It is preferably 25 nm or less. More preferably, it is 20 nm or less.

[0064] The transparent conductive film of the present invention is the above-mentioned transparent conductive film, the transparent metal oxide is an indium-tin composite oxide, and the concentration of tin oxide contained in the transparent metal oxide layer is 8% by mass or more and 50% by mass or less.

[0065] As a transparent metal oxide that is a structural element of the transparent conductive film of the present invention, conductivity, transparency, and environmental stability are required. As a transparent metal oxide having excellent conductivity, transparency, and environmental stability, indium-tin composite oxide is preferred. The concentration of tin oxide contained in the transparent metal oxide is preferably 8% by mass or more and 50% by mass or less. If the concentration of tin oxide contained in the transparent metal oxide is 8% by mass or more, the environmental stability is excellent, and thus it is preferred. It is preferably 10% by mass or more. If the concentration of tin oxide contained in the transparent metal oxide is 50% by mass or less, it is easy to pattern the transparent metal oxide and the metal nanowires using an etching solution, and thus it is preferred. It is preferably 40% by mass or less.

[0066] The transparent conductive film of the present invention is the above-mentioned transparent conductive film, the diameter of the metal nanowires is 2 to 80 nm, and the length of the metal nanowires is 10 to 100 μm.

[0067] The transparent conductive film of the present invention preferably has a metal nanowire diameter of 2 to 80 nm. If the diameter of the metal nanowires is 2 nm or more, the metal nanowires are not easily broken during molding, so the elongation rate of the conductivity based on molding is high, and thus it is preferred. It is preferably 5 nm or more. If the diameter of the metal nanowires is 80 nm or less, the transparency is excellent, and thus it is preferred. It is preferably 50 nm or less.

[0068] The transparent conductive film of the present invention preferably has a metal nanowire length of 10 to 100 μm. If the length of the metal nanowires is 10 μm or more, the metal nanowires can sufficiently contact each other even during molding, so the elongation rate of the conductivity based on molding is high, and thus it is preferred. It is preferably 20 μm or more. If the length of the metal nanowires is 100 μm or less, the breakage of the metal nanowires is reduced even during molding, so the elongation rate of the conductivity based on molding is high, and thus it is preferred.

[0069] The transparent conductive film of the present invention is the above-mentioned transparent conductive film, and has a curable resin layer on the surface opposite to the surface on which the metal nanowire layer is laminated on the transparent plastic film substrate.

[0070] The transparent conductive film of the present invention preferably has a curable resin layer on the surface opposite to the surface on which the metal nanowire layer is laminated on the transparent plastic film substrate. By having the curable resin layer, the transparent conductive film is not easily damaged, and thus it is preferred.

[0071] The transparent conductive film of the present invention is the above-mentioned transparent conductive film, and further has a functional layer between the transparent plastic film substrate and the metal nanowire layer.

[0072] The transparent conductive film of the present invention preferably further has a functional layer between the transparent plastic film substrate and the metal nanowire layer. The functional layer improves the adhesion to the metal nanowires and the transparent metal oxide, and as a result, the elongation rate of the conductivity based on the molding process becomes higher, so it is preferred.

[0073] In one mode, when the transparent metal oxide layer covers at least a part of the metal nanowire layer, the transparent metal oxide layer is configured to adhere to at least one of the transparent plastic film substrate and the functional layer. In such a correspondence, the transparent metal oxide layer can also inhibit the peeling of the metal nanowires from the transparent plastic film substrate and can exhibit excellent three-dimensional processability and ductility.

[0074] In one mode, the functional layer may also contain particles to adjust the haze or provide multiple functional layers with different refractive indices to improve the visual recognition. In addition, in order to prevent the precipitation of monomers and oligomers precipitated from the transparent plastic film substrate, a functional layer may also be provided.

[0075] The manufacturing method for obtaining the transparent conductive film of the present invention is not particularly limited, and for example, the following manufacturing methods can be preferably exemplified.

[0076] As a method for coating the metal nanowire layer on at least one surface of the transparent plastic film substrate, there is no particular limitation, and conventionally known methods such as a bar coating method, a gravure coating method, and a reverse coating method can be used.

[0077] As a method for forming a transparent metal oxide film of indium-tin composite oxide on the metal nanowire layer coated on the transparent plastic film substrate, a sputtering method is preferably used. In order to manufacture the transparent conductive film with high productivity, a so-called roll sputtering device is preferably used: a film roll is supplied and wound into the shape of a film roll after film formation. In the film formation atmosphere, a mass flow controller is used to introduce an inert gas and oxygen, and a sintered target of indium-tin composite oxide is used to adjust the thickness of the transparent metal oxide film of indium-tin composite oxide to 2 to 30 nm. It is preferably adopted to form a transparent metal oxide film on the transparent plastic film coated with the metal nanowire layer. In addition, the thickness of the transparent metal oxide film can be measured by fluorescent X-ray measurement.

[0078] In order to improve production efficiency, multiple sintering targets of indium-tin composite oxide can also be arranged relative to the flow direction of the film. In addition, when using a mass flow controller in the film-forming atmosphere, it is okay even if a gas containing hydrogen atoms (gases containing hydrogen atoms such as hydrogen, ammonia, hydrogen + argon mixed gas, etc., are not particularly limited. However, water is excluded.) flows through. It is known that if there is a lot of water in the film-forming atmosphere, the film quality of the transparent metal oxide film will deteriorate, resulting in adverse effects on the film quality of the transparent metal oxide film such as the surface resistance value deviating from the preferred range. Therefore, the moisture content in the film-forming atmosphere is also an important factor. By controlling the central value (the value in the middle of the maximum value and the minimum value) of the moisture pressure ratio of the film-forming atmosphere during sputtering on the film roll to the inert gas to 7.00×10 -3 The following can suppress the deterioration of the film quality of the transparent metal oxide film, so it is preferred. In order to control the moisture content in the film-forming atmosphere, in addition to the rotary pump, turbo molecular pump, and cryopump that are often used as the exhaust devices of the sputtering machine, the following bombardment process, the limitation of the height difference of the unevenness on the end face of the film roll, and pasting a protective film with low water absorption on the opposite side of the surface where the transparent metal oxide film is formed are also preferred. When forming the transparent metal oxide film, it is preferred to reduce the amount of water released from the film. In addition, it is preferred to make the film temperature during sputtering 0 °C or lower and form a transparent metal oxide film on a transparent plastic film coated with a metal nanowire layer. The film temperature during film formation is replaced by the set temperature of the temperature controller that adjusts the temperature of the central roller in contact with the traveling film. Here, Figure 2 FIG. shows a schematic diagram of an example of a sputtering device preferably used in the present invention. The traveling film 4 partially contacts the surface of the central roller 5 and travels. An indium-tin sputtering target 7 is provided via a chimney 6, and a thin film of indium-tin composite oxide is deposited and laminated on the surface of the film 4 traveling on the central roller 5. The central roller 5 is temperature-controlled by a temperature controller (not shown). If the film temperature is 0 °C or lower, the release of impurity gases such as water and organic gases from the film that deteriorate the film quality of the transparent metal oxide film can be suppressed, so it is preferred. In addition, in order to make the surface resistance and total light transmittance of the transparent conductive film reach practical levels, it is preferred to add oxygen during sputtering.

[0079] In the control of the moisture content when forming indium-tin composite oxide on a transparent plastic film coated with a metal nanowire layer, for the following two reasons, it is preferred to actually observe the moisture content during film formation compared to observing the achieved vacuum degree.

[0080] As the first reason, when forming a film on a transparent plastic film coated with a metal nanowire layer by sputtering, the film is heated and water is released from the film, so the moisture content in the film-forming atmosphere increases and is higher than the moisture content when measuring the achieved vacuum degree. Therefore, compared with expressing it by the achieved vacuum degree, it is more accurate to express it by the moisture content during film formation.

[0081] The second reason is the case of a device that inputs a large amount of transparent plastic films coated with a metal nanowire layer. In such a device, the film is input in the form of a film roll. When the film is input into the vacuum chamber as a roll, the water on the outer layer part of the roll easily falls off, but the water on the inner layer part of the roll is difficult to fall off. This is because when measuring the attainment of the vacuum degree, the film roll stops, but when forming the film, the film roll advances. Therefore, the inner layer part of the film roll containing a large amount of water is unrolled, and thus the moisture content in the film-forming atmosphere increases, compared with the moisture content when measuring the attainment of the vacuum degree. In the present invention, when controlling the moisture content in the film-forming atmosphere, it is possible to preferably respond by observing the ratio of the moisture pressure in the film-forming atmosphere during sputtering to the inert gas.

[0082] Preferably, before forming the transparent metal oxide film, the film is passed through a bombardment process. The so-called bombardment process means that in a state where only an inert gas such as argon or a mixed gas of a reactive gas such as oxygen and an inert gas is introduced, a voltage is applied to discharge and generate plasma. Specifically, it is preferable to bombard the film by RF sputtering using a SUS target or the like. Since the film is exposed to plasma through the bombardment process, water and organic components are released from the film, and the water and organic components released from the film when forming the transparent metal oxide film are reduced. Therefore, the film quality of the transparent metal oxide film becomes good, and thus it is preferable. In addition, since the layer in contact with the transparent metal oxide film is activated through the bombardment process, the adhesion of the transparent metal oxide film is improved. Therefore, the elongation rate having conductivity based on forming processing becomes high, and thus it is preferable.

[0083] For the film roll used for forming the transparent metal oxide film, the height difference between the most convex part and the most concave part in the roll end face is preferably 10 mm or less. If it is 10 mm or less, it is not easy to release water and organic components from the film end face when the film roll is input into the sputtering device. Therefore, the film quality of the transparent metal oxide film becomes good, and thus it is preferable.

[0084] In the film (transparent plastic film substrate) for forming the transparent metal oxide film, it is preferable to paste a protective film with a low water absorption rate on the opposite side of the surface for forming the transparent metal oxide film. By pasting a protective film with a low water absorption rate, it is not easy to release gases such as water from the film substrate, and the film quality of the transparent metal oxide film becomes good, and thus it is preferable. As the substrate of the protective film with a low water absorption rate, polyethylene, polypropylene, cycloolefin, etc. are preferable.

[0085] In the method of forming a transparent metal oxide film of indium-tin composite oxide on a transparent plastic film substrate coated with a metal nanowire layer, it is preferable to introduce oxygen during sputtering. If oxygen is introduced during sputtering, no adverse conditions will occur due to the lack of oxygen in the transparent metal oxide film of indium-tin composite oxide, the surface resistance of the transparent conductive film is low, and the total light transmittance is high, which is preferable. Therefore, in order to bring the surface resistance and total light transmittance of the transparent conductive film to a practical level, it is preferable to introduce oxygen during sputtering.

[0086] <transparent plastic film substrate>

[0087] The transparent plastic film substrate used in the present invention refers to a film obtained by melt-extruding or solution-extruding an organic polymer in a film form and, if necessary, stretching, cooling, and thermally fixing it in the longitudinal direction and / or width direction. As the organic polymer, polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate glycol, polypropylene terephthalate, polybutylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene ether, polystyrene, syndiotactic polystyrene, norbornene-based polymer, polymethyl methacrylate, etc. can be cited.

[0088] Among these organic polymers, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, etc. are preferable. In addition, these organic polymers can copolymerize a small amount of monomers of other organic polymers or blend other organic polymers.

[0089] Within the scope that does not damage the purpose of the present invention, the transparent plastic film substrate used in the present invention can be subjected to surface activation treatments such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc. on the film.

[0090] The thickness of the transparent plastic film substrate of the transparent conductive film in the present invention is preferably in the range of 50 μm or more and 250 μm or less, and more preferably 75 μm or more and 200 μm or less. If the thickness of the plastic film is 50 μm or more, the mechanical strength can be maintained, and breakage during processing can be prevented, so it is preferable. On the other hand, when the thickness is 250 μm or less, the plastic film can be bent moderately, so the molding processability is excellent, so it is preferable.

[0091] The composition of the metal nanowires used in the present invention is not particularly limited, and gold, silver, copper, or their alloys are preferred. From the viewpoints of conductivity and economy, silver is preferably used. After the metal nanowires are in a state of being dispersed in an alcohol-based solvent, they are preferably coated on at least one surface of a transparent plastic film substrate.

[0092] Figure 3 It is a schematic diagram showing the configuration of the transparent plastic film substrate and the metal nanowire layer according to the present invention from the visual recognition side. The metal nanowires 8 forming the metal nanowire layer are arranged above the transparent plastic film substrate 9. The metal nanowires 8 can be linear or curved. In addition, within the range not damaging the effects of the present invention, the diameter, length, etc. of the metal nanowires can be appropriately selected. In one embodiment, as described above, the diameter of the metal nanowires is 2 nm or more and 80 nm or less, and the length of the metal nanowires is 10 μm or more and 100 μm or less. For the metal nanowire layer, various metal nanowires are three-dimensionally entangled, and it can also take the form of a three-dimensional network structure.

[0093] In addition, the metal nanowire layer may also have voids 10. For example, in the voids of the metal nanowire layer, a transparent metal oxide forming a transparent metal oxide layer may be present. In addition, the transparent metal oxide may not fill all the voids 10.

[0094] As the resin contained in the curable resin layer and the functional layer used in the present invention, there is no particular limitation as long as it is a resin that is cured by applying energy such as heating, ultraviolet irradiation, or electron beam irradiation, and examples thereof include acrylamide-based resins, silicone resins, acrylic resins, epoxy resins, melamine resins, polyester resins, polyurethane resins, etc. From the viewpoint of productivity, a ultraviolet curable resin is preferably used as the main component. From the viewpoint of productivity, a ultraviolet curable resin is preferably used as the main component. As such a ultraviolet curable resin, for example, a resin obtained by reacting a hydroxyl group-containing acrylamide with an isocyanate compound can be cited. As needed, various polymerization initiators, antistatic agents, refractive index regulators, leveling agents, defoaming agents, pH regulators, etc. can be used.

[0095] Examples of various polymerization initiators are listed. Ultraviolet curable resins are usually used by adding a photoinitiator. As the photoinitiator, known compounds that absorb ultraviolet light and generate free radicals can be used without particular limitation, and examples of such photoinitiators include various benzoin compounds, phenyl ketone compounds, benzophenone compounds, etc.

[0096] In addition, in order to improve the adhesion between the metal nanowire layer and the functional layer, it is effective to treat the surface of the functional layer using the methods described below. As specific methods, examples include: a discharge treatment method such as glow or corona discharge for increasing carbonyl, carboxyl, and hydroxyl groups; a chemical agent treatment method using an acid or a base for increasing polar groups such as amino, hydroxyl, and carbonyl groups, etc.

[0097] In addition, in the present invention, in the curable resin layer and the functional layer, in addition to the curable resin as the main structural component, inorganic particles and organic particles can also be used in combination. By dispersing the inorganic particles and organic particles in the curable resin, unevenness can be formed on the surfaces of the curable resin layer and the functional layer, and the surface roughness in a wide area can be improved.

[0098] Examples of the inorganic particles include silica and the like. Examples of the organic particles include polyester resin, polyolefin resin, polystyrene resin, polyamide resin, etc. The particles contained in the curable resin layer and the functional layer can be the same particles or different particles.

[0099] In addition to the inorganic particles and organic particles, in addition to the curable resin as the main structural component, it is also preferable to use in combination a resin incompatible with the curable resin. By adding a small amount of the incompatible resin to the curable resin of the substrate, phase separation can occur in the curable resin, and the incompatible resin can be dispersed in a particulate form. Through the dispersed particles of the incompatible resin, unevenness can be formed on the surfaces of the curable resin layer and the functional layer, and the surface roughness in a wide area can be improved.

[0100] Examples of the incompatible resin include polyester resin, polyolefin resin, polystyrene resin, polyamide resin, etc.

[0101] By forming unevenness on the surfaces of the curable resin layer and the functional layer, functions such as improvement of the winding property of the film and light diffusion can be imparted.

[0102] The ultraviolet curable resin, the photoinitiator, and the resin incompatible with the inorganic particles, organic particles, and ultraviolet curable resin are respectively dissolved in a common solvent to prepare a coating solution. The solvent used is not particularly limited. For example, alcohol solvents such as ethanol and isopropyl alcohol, ester solvents such as ethyl acetate and butyl acetate, ether solvents such as dibutyl ether and ethylene glycol monoethyl ether, ketone solvents such as methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbon solvents such as toluene, xylene, and solvent naphtha can be used alone or in combination.

[0103] The concentration of the resin component in the coating solution can be appropriately selected in consideration of the viscosity corresponding to the coating method and the like. In addition, if necessary, other known additives such as silicone-based leveling agents can also be added to the coating solution.

[0104] In the present invention, the prepared coating liquid is coated on a transparent plastic film substrate. The coating method is not particularly limited, and conventionally known methods such as a bar coating method, a gravure coating method, and a reverse coating method can be used.

[0105] In the subsequent drying process, the solvent in the coated coating liquid is evaporated and removed. In this process, the high molecular weight polyester resin uniformly dissolved in the coating liquid becomes particles and precipitates in the ultraviolet curable resin. After drying the coating film, ultraviolet rays are irradiated onto the plastic film, whereby the ultraviolet curable resin is crosslinked / cured to form a cured resin layer and a functional layer. In this curing process, the particles of the high molecular weight polyester resin are fixed in the cured resin layer and the functional layer, and protrusions are formed on the surfaces of the cured resin layer and the functional layer, increasing the surface roughness in a wide area.

[0106] In addition, the thickness of the cured resin layer is preferably in the range of 0.1 μm or more and 15 μm or less. More preferably, it is in the range of 0.5 μm or more and 10 μm or less, and particularly preferably in the range of 1 μm or more and 8 μm or less. When the thickness of the cured resin layer is 0.1 μm or more, the cured resin layer is not easily damaged, so it is preferred. On the other hand, if it is 15 μm or less, the productivity is good, so it is preferred.

[0107] In addition, the thickness of the functional layer is preferably in the range of 0.01 μm or more and 15 μm or less. More preferably, it is in the range of 0.05 μm or more and 15 μm or less, and particularly preferably in the range of 0.07 μm or more and 10 μm. If the thickness of the functional layer is 0.01 μm or more, the adhesion of the metal nanowire and the transparent metal oxide to the functional layer is stable and excellent. As a result, the elongation rate of the conductivity based on the forming process is high, so it is preferred. On the other hand, if it is 15 μm or less, the productivity is good, so it is preferred.

[0108] As described above, the transparent conductive film of the present invention not only has easy formability but also has various characteristics and can be applied to anti-fog covers, electromagnetic wave shielding, etc. for displays, touch panels, cameras, etc.

[0109] Examples

[0110] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by any of these examples. In addition, various measurements and evaluations in the examples are carried out by the following methods.

[0111] (1) Total light transmittance

[0112] According to JIS-K7361-1:1997, the total light transmittance was measured using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0113] (2) Surface resistance value

[0114] Measurement was carried out by the four-terminal method in accordance with JIS-K7194:1994. The measuring instrument used was Lotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytical Technology Co., Ltd.

[0115] (3) Molding processability test

[0116] Samples were cut at 60 mm in the longitudinal direction (MD) of the transparent conductive film and at 20 mm in the width direction of the transparent conductive film. Next, in the MD direction, the two short sides of the sample were clamped by metal fittings at about 10 mm portions, and the distance A between the two metal fittings was recorded. Next, the sample was stretched along the longitudinal direction of the transparent conductive film. The distance B between the two metal fittings after stretching was recorded, and B÷A×100 (%) was taken as the elongation rate. Next, the tester was brought into contact with positions that were 5 mm apart from the center position of the stretched transparent conductive film in the MD direction, and the resistance value was measured. The image during measurement is as Figure 4 shown. In Figure 4 , a pair of metal fittings 11, a transparent conductive film 12, the center position 13 of the transparent conductive film, the position 14 where the tester contacts, and other positions 15 where the tester contacts are shown.

[0117] At this time, if the resistance value is 40 MΩ or less, it is judged to have conductivity. The maximum elongation rate with conductivity is recorded. In addition, when stretching the transparent conductive film, stretching can also be carried out in a heated state. In the examples and comparative examples, stretching was carried out at 115 °C.

[0118] (4) Environmental stability test

[0119] The surface resistance value of the transparent conductive film was measured as the initial value. Next, the surface resistance values after treating the transparent conductive film at 60 °C 95% RH for 240 hours, at 85 °C 85% RH for 240 hours, and at 90 °C for 240 hours were measured, and division operation was performed using the resistance values of the surface resistance values. A thermo-hygrostat was used to carry out the 60 °C 95% RH treatment and the 85 °C 85% RH treatment. An oven was used for the 90 °C treatment.

[0120] (5) Evaluation of the presence or absence of voids in the metal nanowire layer on the transparent plastic film substrate

[0121] When observing the surface of the transparent conductive film having a metal nanowire layer and a transparent metal oxide layer with an optical microscope at a magnification of 100 times, if the transparent plastic film substrate was also seen in addition to the fibrous metal nanowires, it was judged to have voids.

[0122] (6) Thickness of the transparent metal oxide film (film thickness)

[0123] The film thickness of the transparent metal oxide film layer was measured by the calibration curve method using a scanning fluorescent X-ray analyzer (manufacturer: Rigaku, model: ZSX Primus II). The diameter of the sample size was approximately 5 cm.

[0124] (7) Determination of the content ratio of tin oxide contained in the transparent metal oxide film

[0125] A test sample (about 15 cm 2 ) was cut, 20 ml of 6 mol / l hydrochloric acid was added to a quartz Erlenmeyer flask, and the film was sealed without acid volatilization. It was left for 9 days while shaking frequently at room temperature to dissolve the transparent metal oxide film. The remaining film was taken out, and the hydrochloric acid in which the transparent metal oxide film was dissolved was used as the measurement solution. In and Sn in the dissolved solution were obtained by the calibration curve method using an ICP emission analyzer (manufacturer: Rigaku, model: CIROS-120 EOP). The measurement wavelengths of each element were selected as wavelengths with no interference and high sensitivity. In addition, commercially available standard solutions of In and Sn were used as the standard solutions.

[0126] (8) Thickness of the metal nanowire layer

[0127] A cross-section of the transparent conductive film sample piece was made with a microtome. Next, cross-section observation was performed using a scanning electron microscope (manufactured by Keyence Corporation, VE-8800) at a site with no significant damage. The film thickness was determined from the image obtained by photographing at an observation magnification of 9,000 times.

[0128] (9) Diameter and length of the metal nanowires

[0129] The surface of the transparent conductive film on which the metal nanowires were laminated was observed using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, S-4800). Ten arbitrary metal nanowires were selected from the image obtained by photographing at an observation magnification of 3,000 times, and the average value of the lengths of the respective metal nanowires was taken as the length of the metal nanowires. Ten arbitrary metal nanowires were selected from the image obtained by photographing at an observation magnification of 100,000 times, and the average value of the diameters of the respective metal nanowires was taken as the diameter of the metal nanowires.

[0130] The transparent plastic film substrate used in the examples and comparative examples was a polymethyl methacrylate film, i.e., an acrylic film. As the curable resin layer and the functional layer, 2.5 parts by mass of hydroxyethyl acrylamide, 0.4 parts by mass of a polymerization initiator (manufactured by IGM Resins B.V., Irgacure 184), and 0.01 parts by mass of a catalyst (manufactured by Nitto Kasei Co., Ltd., neostane U-130) were dispersed in 6.9 parts by mass of methyl ethyl ketone as the main agent. 8.00 parts by mass of an isocyanate compound (manufactured by Mitsui Chemicals, Inc., D-110N) was dispersed in 12.0 parts by mass of methyl ethyl ketone as the curing agent. The ratio of the hydroxyl group of hydroxyethyl acrylamide in the main agent to the isocyanate group in the curing agent was made 1:1, and 10 parts by mass of the main agent solution was mixed with 20 parts by mass of the curing agent solution so that the thickness of the coating film became 5 μm, and the prepared coating liquid was applied to the acrylic film using a Meyer rod. After drying at 80 °C for 1 minute, ultraviolet rays (light quantity: 300 mJ / cm 2 ) were irradiated using an ultraviolet irradiation device (manufactured by EYEGRAPHICS, model UB042-5AM-W) to cure the coating film.

[0131] In addition, the functional layer was provided on the surface of the transparent plastic film substrate on the side opposite to the above curable resin layer.

[0132] (Examples 1 to 5)

[0133] Each example level was carried out as follows under the conditions shown in Table 1.

[0134] On the transparent plastic film substrate or the functional layer, a liquid in which silver nanowires were dispersed in isopropyl alcohol was coated using a Meyer rod under the conditions of Table 1 as the metal nanowires. Then, it was dried at 90 °C for 1 minute.

[0135] Next, the film was put into a vacuum chamber and evacuated to 1.5×10 -4 Pa. Next, after introducing oxygen, argon was introduced as an inert gas so that the total pressure became 0.6 Pa.

[0136] At 3 W / cm 2Electric power density is applied to a sintered target of indium-tin composite oxide, and a transparent metal oxide film is formed by DC magnetron sputtering. Regarding the film thickness, it is controlled by changing the speed when the film passes through the target. In addition, regarding the ratio of the water vapor pressure of the film-forming atmosphere during sputtering to the inert gas, it is measured using a gas analysis device (manufactured by Inficon, Transpector XPR3). In each example level, in order to adjust the ratio of the water vapor pressure of the film-forming atmosphere during sputtering to the inert gas, as described in Table 1, the presence or absence of a bombardment process, the uneven height difference at the end face of the film roll, and the temperature of the heat carrier of the temperature controller that controls the temperature of the center roll in contact with the film during travel are adjusted. The temperature exactly in the middle between the maximum and minimum temperatures from the start to the end of film formation on the film roll is recorded as the center value in Table 1.

[0137] Measurements were performed on the film formed by laminating transparent metal oxide film forming layers. The measurement results are shown in Table 1.

[0138] (Comparative Examples 1 to 3)

[0139] In Comparative Examples 1 and 3, except for not providing a metal nanowire layer, a transparent conductive film was produced and evaluated under the conditions described in Table 1 in the same manner as in Example 1. In addition, in Comparative Example 2, except for not providing a transparent metal oxide layer, a transparent conductive film was produced and evaluated under the conditions described in Table 1 in the same manner as in Example 1. The results are shown in Table 1.

[0140] (Reference Example)

[0141] In the reference example, a transparent conductive film was produced and evaluated under the conditions described in Table 1 in the same manner as in Example 1. The results are shown in Table 1.

[0142] [Table 1]

[0143]

[0144] [Table 2]

[0145]

[0146] As described in Table 1, the total light transmittance, surface resistance, and elongation rate with conductivity based on molding processing of the transparent conductive films described in Examples 1 to 5 are within the scope of the present invention. Therefore, even when formed into a three-dimensional shape in anti-fog covers, electromagnetic wave shielding, etc. of displays, touch panels, cameras, etc., the characteristics required for each application can be fully exhibited. However, Comparative Examples 1 to 3 cannot fully satisfy the total light transmittance, surface resistance, and elongation rate with conductivity based on molding processing.

[0147] --Industrial Applicability--

[0148] As described above, according to the present invention, it is possible to provide a transparent conductive film having excellent characteristics in terms of total light transmittance, surface resistance, and elongation rate having conductivity based on molding processing, which is extremely useful for anti-fog covers, electromagnetic wave shielding, etc. of displays, touch panels, cameras, etc. that require three-dimensional shapes.

[0149] -Symbol Explanation-

[0150] 1 Transparent plastic film substrate

[0151] 2 Metal nanowire layer

[0152] 3 Transparent metal oxide layer

[0153] 4 Film

[0154] 5 Center roller

[0155] 6 Chimney

[0156] 7 Target of indium-tin composite oxide

[0157] 8 Metal nanowire

[0158] 9 Transparent plastic film

[0159] 10 Void

[0160] 11 Metal fitting

[0161] 12 Transparent conductive film

[0162] 13 Central position of the transparent conductive film

[0163] 14 Position of the contact tester

[0164] 15 Position of the contact tester.

Claims

1. A transparent conductive film having a transparent plastic film substrate and a transparent metal oxide layer, wherein a metal nanowire layer and a transparent metal oxide layer are sequentially provided on at least one side of the transparent plastic film substrate, the total light transmittance of the transparent conductive film according to JIS-K7361-1 is 75% or more and 95% or less, the surface resistance value of the transparent conductive film is 1 to 150 Ω / square, and when stretched in the range of +10% or more and +200% or less with respect to the length of the unstretched transparent conductive film, it has conductivity, the transparent conductive film is configured such that the transparent metal oxide layer covers at least a part of the metal nanowire layer and then adheres to the transparent plastic film substrate, the thickness of the metal nanowire layer is 0.10 to 1.00 μm, and further the thickness of the transparent metal oxide layer determined by fluorescent X-ray is 2 to 30 nm.

2. The transparent conductive film according to claim 1, wherein the surface resistance value of the transparent conductive film under the condition of being treated at 60 °C and 95% RH for 240 hours and the surface resistance value of the transparent conductive film under the condition of being treated at 85 °C and 85% RH for 240 hours are respectively 0.5 times or more and 1.5 times or less with respect to the surface resistance value of the transparent conductive film before the above heat treatment.

3. The transparent conductive film according to claim 1 or 2, wherein the surface resistance value of the transparent conductive film under the condition of being treated at 90 °C for 240 hours is respectively 0.5 times or more and 1.5 times or less with respect to the surface resistance value of the transparent conductive film before the above heat treatment.

4. The transparent conductive film according to claim 1 or 2, wherein the transparent metal oxide is indium-tin composite oxide, the concentration of tin oxide contained in the transparent metal oxide layer is 8% by mass or more and 50% by mass or less.

5. The transparent conductive film according to claim 1 or 2, wherein the diameter of the metal nanowire is 2 to 80 nm, and the length of the metal nanowire is 10 to 100 μm.

6. The transparent conductive film according to claim 1 or 2, wherein a curable resin layer is provided on the opposite surface of the transparent plastic film substrate where the metal nanowire layer is laminated.

7. The transparent conductive film according to claim 1 or 2, wherein a functional layer is further provided between the transparent plastic film substrate and the metal nanowire layer.

8. The transparent conductive film according to claim 1 or 2, wherein the metal nanowire layer has voids.

Images