Transparent Conductive Film

Abstract

To provide a transparent conductive film excellent in flex resistance, responding to a requirement of high flex resistance with regard to a transparent conductive film so as to cope with a display such as a flexible display having flexibility.SOLUTION: A transparent conductive film 1 sequentially includes a transparent substrate 2, a curable resin layer 3 and a transparent conductive layer 4. The transparent conductive film 1 includes silica particles in the curable resin layer, and has a surface resistance value of 45 Ω / sq. or less, and flex resistance with 10 mm or less of a flexure diameter measured with a flexibility test.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transparent conductive film, and more particularly to a transparent conductive film suitable for optical applications. [Background technology]

[0002] Transparent conductive films, in which a transparent conductive layer made of indium tin oxide (ITO) is formed into a desired electrode pattern, have been used for optical applications such as touch panels.

[0003] The transparent conductive film may be required to have bending resistance depending on the purpose and application.

[0004] As such a transparent conductive film, a transparent conductive film has been proposed which comprises a transparent plastic film substrate and a transparent conductive film in that order, and which has a bending diameter of 10.7 mm in a flexibility test (see, for example, Example 7 of Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 126466 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been a trend toward a demand for greater flexibility than the transparent conductive film of Patent Document 1 in order to accommodate flexible displays such as flexible displays (foldable, bendable, rollable displays, etc.).

[0007] The present invention provides a transparent conductive film having excellent flex resistance. [Means for solving the problem]

[0008] The present invention [1] includes a transparent conductive film having, in that order, a transparent substrate, a cured resin layer, and a transparent conductive layer, wherein the cured resin layer contains silica particles, and the bending diameter measured by the following flexibility test is 10 mm or less.

[0009] Flexibility test: A transparent conductive film heat-treated at 165°C for 75 minutes was cut into a 20mm x 80mm rectangle. The short sides of the rectangle were then connected with a tester, and the resistance value was measured. The transparent conductive film was bent so that the short sides of the rectangle approached each other, with the transparent conductive layer facing outward. The bending diameter (mm) of the transparent conductive film was measured when the resistance value of the tester began to increase.

[0010] The present invention [2] includes the transparent conductive film according to the above [1], wherein the thickness of the transparent conductive layer exceeds 35 nm.

[0011] The present invention [3] includes the transparent conductive film according to the above [1] or [2], wherein the surface resistance of the transparent conductive layer is 45 Ω / □ or less.

[0012] The present invention [4] includes the transparent conductive film according to any one of the above [1] to [3], wherein the thickness of the transparent substrate is 45 μm or less. [Effects of the Invention]

[0013] In the transparent conductive film of the present invention, the cured resin layer contains silica particles.

[0014] Therefore, it has excellent bending resistance.

[0015] Furthermore, the transparent conductive film has a bending diameter of 10 mm or less as measured by a flexibility test.

[0016] Therefore, it can be suitably used in optical devices and their constituent parts that require bending resistance. [Brief explanation of the drawings]

[0017]

Figure 1

Figure 2

Figure 3

[0018] One embodiment of the transparent conductive film of the present invention will be described with reference to FIG.

[0019] In Figure 1, the up-down direction of the paper surface is the up-down direction (thickness direction), and the upper side of the paper surface is the upper side (one side in the thickness direction), and the lower side of the paper surface is the lower side (the other side in the thickness direction). Also, the left-right direction and the depth direction of the paper surface are surface directions perpendicular to the up-down direction. Specifically, they conform to the directional arrows in each figure.

[0020] 1. Transparent conductive film The transparent conductive film 1 has a film shape (including a sheet shape) with a predetermined thickness, extends in a plane direction perpendicular to the thickness direction, and has a flat upper surface and a flat lower surface. The transparent conductive film 1 is, for example, a component of a touch panel substrate or an electromagnetic wave shield provided in an image display device, i.e., it is not an image display device. In other words, the transparent conductive film 1 is a component for producing an image display device or the like, does not include an image display element such as an OLED module, is distributed as a separate component, and is an industrially applicable device.

[0021] Specifically, as shown in FIG. 1, the transparent conductive film 1 includes a transparent substrate 2, a cured resin layer 3, and a transparent conductive layer 4 in this order toward one side in the thickness direction. More specifically, the transparent conductive film 1 includes a transparent substrate 2, a cured resin layer 3 disposed on the upper surface (one surface in the thickness direction) of the transparent substrate 2, and a transparent conductive layer 4 disposed on the upper surface (one surface in the thickness direction) of the cured resin layer 3. Preferably, the transparent conductive film 1 includes only the transparent substrate 2, the cured resin layer 3, and the transparent conductive layer 4.

[0022] The thickness of the transparent conductive film 1 is, for example, 200 μm or less, preferably 150 μm or less, and more preferably 100 μm or less.

[0023] 2. Transparent Substrate The transparent substrate 2 is a transparent substrate for ensuring the mechanical strength of the transparent conductive film 1.

[0024] The transparent substrate 2 has a film shape. The transparent substrate 2 is disposed over the entire lower surface of the cured resin layer 3 so as to be in contact with the lower surface of the cured resin layer 3.

[0025] The transparent substrate 2 is, for example, a transparent polymer film. Examples of the material of the transparent substrate 2 include olefin resins such as polyethylene, polypropylene, and cycloolefin polymer; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate; (meth)acrylic resins (acrylic resin and / or methacrylic resin) such as polymethacrylate; polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, etc. Preferably, olefin resins are mentioned, and more preferably, cycloolefin polymer is mentioned.

[0026] The thickness of the transparent substrate 2 is, for example, 60 μm or less, preferably 45 μm or less.

[0027] If the thickness of the transparent substrate 2 is equal to or less than the above upper limit, the bending resistance can be improved.

[0028] 3.Cured resin layer The cured resin layer 3 has a film shape and is disposed on the entire lower surface of the transparent conductive layer 4 so as to be in contact with the lower surface of the cured resin layer 3.

[0029] The cured resin layer 3 may be a hard coat layer 5 .

[0030] In the following description, the case where the cured resin layer 3 is a hard coat layer 5 will be described.

[0031] The hard coat layer 5 is a protective layer for preventing scratches from occurring on the transparent substrate 2 during the production of the transparent conductive film 1. The hard coat layer 5 is also an abrasion-resistant layer for preventing scratches from occurring on the transparent conductive layer 4 when the transparent conductive film 1 is laminated.

[0032] The hard coat layer 5 is formed from a hard coat composition.

[0033] The hard coat composition contains a resin and particles.

[0034] Examples of the resin include a curable resin and a thermoplastic resin (such as a polyolefin resin), and preferably a curable resin.

[0035] Examples of the curable resin include active energy ray-curable resins that are cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), and thermosetting resins that are cured by heating, and preferably active energy ray-curable resins.

[0036] Examples of active energy ray-curable resins include polymers having functional groups with polymerizable carbon-carbon double bonds in the molecule, such as vinyl groups and (meth)acryloyl groups (methacryloyl groups and / or acryloyl groups).

[0037] Specific examples of active energy ray curable resins include (meth)acrylic ultraviolet ray curable resins such as urethane acrylate and epoxy acrylate.

[0038] Furthermore, examples of curable resins other than the active energy ray curable resin include thermosetting resins such as urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates.

[0039] The resins can be used alone or in combination of two or more kinds.

[0040] The particles contain silica particles as an essential component.

[0041] That is, the hard coat composition contains silica particles, and the hard coat layer 5 (cured resin layer 3) formed from such a hard coat composition contains silica particles.

[0042] When the hard coat layer 5 (cured resin layer 3) contains silica particles, the flex resistance is improved.

[0043] The particles may also contain particles other than silica particles as optional components.

[0044] Examples of other particles include inorganic particles (excluding silica particles) and organic particles.

[0045] Examples of inorganic particles (excluding silica particles) include zirconia particles, metal oxide particles such as zirconium oxide, titanium oxide, zinc oxide, and tin oxide, and carbonate particles such as calcium carbonate.

[0046] Examples of the organic particles include crosslinked acrylic resin particles and the like.

[0047] Examples of the other particles preferably include inorganic particles (excluding silica particles), and more preferably zirconia particles.

[0048] The other particles can be used alone or in combination of two or more.

[0049] As described above, the particles contain silica particles as an essential component and other particles as an optional component. The particles preferably contain silica particles and other particles.

[0050] If the particles contain silica particles and other particles, the flexural resistance can be improved.

[0051] When the particles contain silica particles and other particles, the blending ratio of the silica particles is, for example, 1 part by mass or more and, for example, 10 parts by mass or less, preferably 5 parts by mass or less, based on 100 parts by mass of the total amount of the silica particles and the other particles. The blending ratio of the other particles is, for example, 90 parts by mass or more, preferably 95 parts by mass or more, and, for example, 99 parts by mass or less, based on 100 parts by mass of the total amount of the silica particles and the other particles.

[0052] The hard coat composition is obtained by mixing a resin and the particles.

[0053] The blending ratio of the resin is, for example, 20% by mass or more and, for example, 40% by mass or less based on the hard coat composition.

[0054] The blending ratio of the particles is, for example, 50% by mass or more and, for example, 80% by mass or less based on the hard coat composition.

[0055] Moreover, known additives such as a leveling agent, a thixotropic agent, and an antistatic agent can be blended in the hard coat composition as necessary.

[0056] To form the hard coat layer 5 (cured resin layer 3), as will be described in detail later, a diluted solution of the hard coat composition is applied to one surface in the thickness direction of the transparent substrate 2, dried, and then the optical adjusting composition is cured by irradiation with ultraviolet light.

[0057] In this way, the hard coat layer 5 is formed.

[0058] From the viewpoint of scratch resistance, the thickness of the hard coat layer 5 (cured resin layer 3) is, for example, 0.1 μm or more, preferably 0.5 μm or more, and for example, 10 μm or less, preferably 3 μm or less. The thickness of the hard coat layer 5 can be measured by cross-sectional observation using, for example, a transmission electron microscope. 4.Transparent conductive layer The transparent conductive layer 4 is a crystalline, transparent layer that exhibits excellent conductivity.

[0059] The transparent conductive layer 4 has a film shape and is disposed on the entire upper surface (one surface in the thickness direction) of the cured resin layer 3 so as to be in contact with the one surface of the cured resin layer 3 in the thickness direction.

[0060] Examples of materials for the transparent conductive layer 4 include metal oxides containing at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. If necessary, the metal oxides may be further doped with metal atoms listed in the above group.

[0061] Specific examples of the transparent conductive layer 4 include indium-containing oxides such as indium tin oxide (ITO) and antimony-containing oxides such as antimony tin oxide (ATO), and preferably indium-containing oxides, and more preferably ITO.

[0062] When using ITO as the material of the transparent conductive layer 4, the content ratio of tin oxide is, for example, 0.5% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, particularly preferably 9% by mass or more, and, for example, 20% by mass or less, preferably 15% by mass or less, based on the total amount of tin oxide and indium oxide.

[0063] If the content ratio of tin oxide is equal to or higher than the above-mentioned lower limit, the reduction of resistance is promoted. If the content ratio of tin oxide is equal to or lower than the above-mentioned upper limit, the transparent conductive layer 4 is excellent in strength.

[0064] In addition, the transparent conductive layer 4 can include a region where the ratio of tin oxide is 8% by mass or more. When the transparent conductive layer 4 includes a region where the ratio of tin oxide is 8% by mass or more, the surface resistance value can be reduced.

[0065] For example, the transparent conductive layer 4 includes a first region 11 as an example of a region where the ratio of tin oxide is 8% by mass or more, and a second region 12 where the ratio of tin oxide is lower than that in the first region 11. Specifically, the transparent conductive layer 4 sequentially includes a layered first region and a layered second region 12 disposed on one side in the thickness direction of the first region 11. Note that the boundary between the first region 11 and the second region 12 is not confirmed by observation with a measuring device and may be unclear. In addition, the transparent conductive layer 4 may have a concentration gradient in which the tin oxide concentration gradually increases from one side to the other side in the thickness direction. When the transparent conductive layer 4 includes the second region in addition to the above-mentioned first region, a desired crystallization rate can be obtained by adjusting the ratio of the regions.

[0066] The ratio of tin oxide in the first region 11 is preferably 9% by mass or more, more preferably 10% by mass or more, and 20% by mass or less.

[0067] The ratio of the thickness of the first region 11 to the thickness of the transparent conductive layer 4 is, for example, more than 50%, preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and also, for example, 99% or less, preferably 97% or less.

[0068] If the ratio of the thickness of the first region 11 is equal to or greater than the above-described lower limit, the ratio of tin oxide in the transparent conductive layer 4 can be increased, and thus, the surface resistance value can be sufficiently decreased.

[0069] The ratio of tin oxide in the second region 12 is, for example, less than 8% by mass, preferably 7% by mass or less, more preferably 5% by mass or less, still more preferably 4% by mass or less, and also, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more.

[0070] The ratio of the thickness of the second region 12 to the thickness of the transparent conductive layer 4 is, for example, 1% or more, preferably 3% or more, and also, for example, 50% or less, preferably 30% or less, more preferably 20% or less, still more preferably 10% or less.

[0071] The ratio of the ratio of tin oxide in the first region to the ratio of tin oxide in the second region (ratio of tin oxide in the first region / ratio of tin oxide in the second region) is, for example, 1.5 or more, preferably 2 or more, more preferably 2.5 or more, and also, for example, 5 or less, preferably 4 or less.

[0072] The tin oxide concentration in each of the transparent conductive layer 4, the first region 11, and the second region 12 is measured by X-ray photoelectron spectroscopy. Alternatively, the content ratio of tin oxide can also be estimated from the components (known) of the target used when forming the amorphous transparent conductive layer 4 by sputtering.

[0073] Further, the transparent conductive layer 4 is crystalline.

[0074] If the transparent conductive layer 4 is crystalline, the specific resistance described later can be decreased.

[0075] The crystallinity of the transparent conductive layer 4 can be determined, for example, by immersing the transparent conductive film 1 in hydrochloric acid (20 ° C, concentration 5% by mass) for 15 minutes, followed by washing with water and drying, and then measuring the resistance between terminals within about 15 mm with respect to the surface on the transparent conductive layer 4 side. In the transparent conductive film 1 after the above immersion, washing with water, and drying, when the resistance between terminals within 15 mm is 10 kΩ or less, the transparent conductive layer 4 is crystalline; on the other hand, when the resistance exceeds 10 kΩ, the transparent conductive layer 4 is amorphous.

[0076] The thickness of the transparent conductive layer 4 is, for example, 20 nm or more, preferably 30 nm or more, more preferably exceeding 35 nm, still more preferably 40 nm or more, and particularly preferably 50 nm or more, and is, for example, 80 nm or less.

[0077] When the thickness of the transparent conductive layer 4 is equal to or greater than the above lower limit, the surface resistance value of the transparent conductive layer 4 can be reduced.

[0078] Incidentally, the thickness of the transparent conductive layer 4 can be measured, for example, by observing a cross section of the transparent conductive film 1 using a transmission electron microscope.

[0079] The specific resistance of the transparent conductive layer 4 is, for example, 2.6×10 -4 Ω·cm or less, preferably 2.4×10 -4 Ω·cm or less, more preferably 2.2×10 -4 Ω·cm or less, still more preferably 2.1×10 -4 Ω·cm or less.

[0080] When the specific resistance of the transparent conductive layer 4 is equal to or less than the above upper limit, excellent electrical characteristics can be exhibited when the transparent conductive layer 4 is patterned and used as an electrode.

[0081] Incidentally, the specific resistance can be measured by the four-terminal method in accordance with JIS K7194.

[0082] The surface resistance value of the transparent conductive layer 4 is, for example, 120 Ω / □ or less, preferably 80 Ω / □ or less, more preferably 50 Ω / □ or less, and even more preferably 45 Ω / □ or less.

[0083] If the surface resistance value of the transparent conductive layer 4 is equal to or less than the above upper limit, excellent electrical properties can be exhibited when the transparent conductive layer 4 is patterned and used as an electrode.

[0084] There is no particular lower limit to the surface resistance of the transparent conductive layer 4. For example, the surface resistance of the transparent conductive layer 4 is usually more than 0 Ω / □ and 1 Ω / □ or more.

[0085] The surface resistance value can be measured by a four-terminal method in accordance with JIS K7194. 5. Transparent conductive film manufacturing method Next, a method for producing the transparent conductive film 1 will be described.

[0086] The method for producing the transparent conductive film 1 includes a first step of disposing a cured resin layer 3 on one surface in the thickness direction of the transparent substrate 2, a second step of forming an amorphous transparent conductive layer 4 by sputtering on one surface in the thickness direction of the cured resin layer 3, and a third step of heating the amorphous transparent conductive layer 4 to form a crystalline transparent conductive layer 4. In this production method, each layer is disposed in order, for example, by a roll-to-roll process.

[0087] In the first step, first, a transparent substrate 2 is prepared.

[0088] Next, a diluted solution of the hard coat composition is applied to one surface in the thickness direction of the transparent substrate 2, and after drying, the hard coat composition is cured by ultraviolet light, thereby forming a hard coat layer 5 (cured resin layer 3) on one surface in the thickness direction of the transparent substrate 2.

[0089] In the second step, an amorphous transparent conductive layer 4 is formed on one surface in the thickness direction of the hard coat layer 5 (cured resin layer 3) by sputtering. Specifically, in a sputtering device, sputtering is performed in the presence of an inert gas while one surface in the thickness direction of the cured resin layer 3 faces a target made of the material of the transparent conductive layer 4. At this time, in addition to the inert gas, a reactive gas such as oxygen may also be present.

[0090] Examples of inert gases include rare gases such as argon. The partial pressure of the inert gas in the sputtering apparatus is, for example, 0.1 Pa or more, preferably 0.3 Pa or more, and, for example, 10 Pa or less, preferably 5 Pa or less, more preferably 1 Pa or less. If the partial pressure of the inert gas is equal to or greater than the above-mentioned lower limit, the energy of the inert gas atoms during sputtering is lowered. This can prevent the amorphous transparent conductive layer 4 from incorporating inert gas atoms.

[0091] The pressure in the sputtering apparatus is the total pressure of the partial pressure of the inert gas and the partial pressure of the reactive gas.

[0092] When ITO is used as the material for the transparent conductive layer 4, a first target and a second target having different tin oxide concentrations can be arranged in this order in the sputtering device along the transport direction of the transparent substrate 2. The material of the first target is, for example, the ITO (tin oxide concentration: 8% by mass or more) in the first region 11 described above. The material of the second target is, for example, the ITO (tin oxide concentration: less than 8% by mass) in the second region 12 described above.

[0093] By the above sputtering, an amorphous transparent conductive layer 4 is formed on one surface of the transparent substrate 2 in the thickness direction.

[0094] When the amorphous transparent conductive layer 4 is formed by sputtering using the first and second targets described above, the amorphous transparent conductive layer 4 includes a first amorphous layer and a second amorphous layer having different tin oxide concentrations, arranged in this order toward one side in the thickness direction. The materials of the first amorphous layer and the second amorphous layer are the same as the materials of the first and second targets. Specifically, the tin oxide concentration in the ITO of the first amorphous layer is, for example, 8% by mass or more. The tin oxide concentration in the ITO of the second amorphous layer is, for example, less than 8% by mass.

[0095] The ratio of the thickness of the first amorphous layer to the thickness of the amorphous transparent conductive layer 4 is, for example, more than 50%, preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more, and is, for example, 99% or less, preferably 97% or less.

[0096] The ratio of the thickness of the second amorphous layer to the thickness of the transparent conductive layer 4 is, for example, 1% or more, preferably 3% or more, and for example, 50% or less, preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less.

[0097] In this way, an amorphous laminate film consisting of the transparent substrate 2 and the amorphous transparent conductive layer 4 is obtained.

[0098] Thereafter, in the third step, the amorphous laminate film is heated. For example, the amorphous transparent conductive layer 4 is heated by a heating device such as an infrared heater or an oven.

[0099] The heating conditions are not particularly limited. The heating temperature is, for example, 90° C. or higher, preferably 110° C. or higher, and for example, 160° C. or lower, preferably 140° C. or lower. The heating time is, for example, 30 minutes or longer, more preferably 60 minutes or longer, and for example, 5 hours or shorter, preferably 3 hours or shorter.

[0100] As a result, the amorphous transparent conductive layer 4 is crystallized to form a crystalline transparent conductive layer 4, as shown in FIG.

[0101] In addition, when the amorphous transparent conductive layer 4 includes a first amorphous layer and a second amorphous layer, the crystalline transparent conductive layer 4 includes a first region 11 and a second region 12 corresponding to the first amorphous layer and the second amorphous layer, respectively.

[0102] As a result, a transparent conductive film 1 is produced which is provided with the transparent substrate 2, the hard coat layer 5 (cured resin layer 3), and the transparent conductive layer 4 in this order.

[0103] Thereafter, the crystalline transparent conductive layer 4 is patterned by, for example, etching, on the transparent conductive film 1. The patterned crystalline transparent conductive layer 4 is used as an electrode for a touch panel (touch sensor) or the like. 6. Action and Effects In the transparent conductive film 1, the cured resin layer 3 (hard coat layer 5) contains silica particles.

[0104] Therefore, it is presumed that the adhesion between the cured resin layer 3 and the transparent conductive layer 4 is improved, resulting in improved flex resistance.

[0105] Specifically, the bending diameter measured by the flexibility test detailed in the examples below is 10 mm or less, preferably 8 mm or less, more preferably 6 mm or less, even more preferably 4 mm or less, particularly preferably 2 mm or less, and most preferably less than 2 mm.

[0106] The transparent conductive film 1 has excellent flex resistance and can therefore be suitably used in optical devices and their constituent parts that require flex resistance, such as flexible displays (foldable, bendable, rollable, etc.).

[0107] Furthermore, from the viewpoint of reducing the surface resistance, the thickness of the transparent conductive layer 4 may be increased (for example, 20 nm or more, preferably 30 nm or more, more preferably more than 35 nm). If the thickness of the transparent conductive layer 4 is increased, the bending resistance may decrease.

[0108] However, because the transparent conductive film 1 has excellent flex resistance, the bending diameter measured by a flexibility test described in detail can be kept within the above range even if the transparent conductive layer 4 is thick. Therefore, the transparent conductive film 1 can be suitably used in optical devices and their component parts that require both flex resistance and low surface resistance. 7. Variations In the modified example, the same components and steps as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, the modified example can achieve the same effects as those in the first embodiment unless otherwise specified. Furthermore, the first embodiment and its modified example can be combined as appropriate.

[0109] The transparent conductive layer 4 may not include the second region in which the proportion of tin oxide is less than 8 mass %, but may include only the first region in which the proportion of tin oxide is 8 mass % or more.

[0110] In the above description, the cured resin layer 3 is the hard coat layer 5, but as shown in FIG. 2, the cured resin layer 3 may be an optical adjustment layer 6.

[0111] In such a case, the transparent conductive film 1 includes the transparent substrate 2, the optical adjustment layer 6 (cured resin layer 3), and the transparent conductive layer 4 in this order.

[0112] The optical adjustment layer 6 is a layer that adjusts the optical properties (e.g., refractive index) of the transparent conductive film 1 in order to suppress the visibility of the pattern of the transparent conductive layer 4 and suppress reflection at the interfaces within the transparent conductive film 1 while ensuring excellent transparency in the transparent conductive film 1.

[0113] The optical adjustment layer 6 is formed from, for example, an optical adjustment composition.

[0114] The optical adjustment composition contains the resin and the particles described above.

[0115] Examples of the resin include the resins listed in the hard coat composition, and preferably, (meth)acrylic ultraviolet curable resins are included.

[0116] As described above, the particles include silica particles as an essential component.

[0117] That is, the optical adjustment composition contains silica particles. And the optical adjustment layer 6 (cured resin layer 3) formed from such an optical adjustment composition contains silica particles.

[0118] When the optical adjustment layer 6 (cured resin layer 3) contains silica particles, the flex resistance is improved.

[0119] Also, as described above, the particles include other particles as optional components.

[0120] Examples of the other particles include the other particles listed in the hard coat composition, and preferably, from the viewpoint of refractive index, preferably, zirconium oxide is included.

[0121] Also, when the particles contain silica particles and other particles, the blending ratio of the silica particles is, for example, 1 part by mass or more, and also, for example, 10 parts by mass or less, preferably 5 parts by mass or less, based on 100 parts by mass of the total amount of the silica particles and the other particles, and the blending ratio of the other particles is, for example, 90 parts by mass or more, preferably 95 parts by mass or more, and also, for example, 99 parts by mass or less, based on 100 parts by mass of the total amount of the silica particles and the other particles.

[0122] And the optical adjustment composition is obtained by mixing the resin and the particles.

[0123] The blending ratio of the resin is, for example, 20% by mass or more and also, for example, 40% by mass or less with respect to the optical adjustment composition.

[0124] Also, the blending ratio of the particles is, for example, 50% by mass or more and, for example, 80% by mass or less with respect to the optical adjustment composition.

[0125] The optical adjustment composition can further contain known additives such as a leveling agent, a thixotropic agent, and an antistatic agent.

[0126] To form the optical adjustment layer 6 (cured resin layer 3), a diluted solution of the optical adjustment composition is applied to one surface in the thickness direction of the transparent substrate 2, and after drying, the optical adjustment composition is cured by ultraviolet irradiation.

[0127] Thereby, the optical adjustment layer 6 is formed.

[0128] From the viewpoint of scratch resistance, the thickness of the optical adjustment layer 6 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and, for example, 10 μm or less, preferably 3 μm or less. The thickness of the optical adjustment layer 6 can be measured by cross-section observation using, for example, a transmission electron microscope.

[0129] Also, the transparent conductive film 1 can also include both the hard coat layer 5 and the optical adjustment layer 6.

[0130] In such a case, as shown in FIG. 3, the transparent conductive film 1 includes a transparent substrate 2, a hard coat layer 5, an optical adjustment layer 6, and a transparent conductive layer 4 in this order. In other words, the transparent conductive film 1 includes a transparent substrate 2, a cured resin layer 3, and a transparent conductive layer 4 in this order.

[0131] Also, an anti-blocking layer can be disposed on the other surface in the thickness direction of the transparent substrate 2.

[0132] In such a case, the transparent conductive film 1 includes an anti-blocking layer, a transparent substrate 2, a cured resin layer 3, and a transparent conductive layer 4 in this order.

[0133] The anti-blocking layer imparts anti-blocking properties to the surfaces of the transparent conductive films 1 that are in contact with each other when the transparent conductive films 1 are stacked in the thickness direction, for example.

[0134] The antiblocking layer has a film shape.

[0135] The material of the antiblocking layer is, for example, an antiblocking composition.

[0136] Examples of anti-blocking compositions include the mixtures described in JP-A-2016-179686.

[0137] The thickness of the antiblocking layer is, for example, 0.1 μm or more and, for example, 10 μm or less. [Example]

[0138] The present invention will be described in more detail below with reference to examples and comparative examples. It should be noted that the present invention is in no way limited to these examples and comparative examples. The specific numerical values of the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values (numeric values defined as "equal to or less than" or "less than") or lower limit values (numeric values defined as "equal to or greater than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the "Description of the Invention" above. 1. Manufacturing of transparent conductive film Example 1 First, a transparent film (thickness: 43 μm) made of a cycloolefin resin was prepared as a transparent substrate.

[0139] Next, a diluted solution of a hard coat composition containing 65.5 parts by mass of zirconia particles, 2.5 parts by mass of silica particles, and 32 parts by mass of a UV-curable resin (acrylic resin) was applied to one surface of the transparent film in the thickness direction, and then dried. After that, the one surface of the transparent film in the thickness direction was irradiated with UV light to cure the hard coat composition. Thus, a hard coat layer with a thickness of 0.7 μm was formed on one surface of the transparent film.

[0140] Thereafter, an amorphous transparent conductive layer having a thickness of 55 nm was formed by sputtering on one surface of the hard coat layer in the thickness direction.

[0141] Specifically, a first target made of ITO with a tin oxide concentration of 10% by weight and a second target made of ITO with a tin oxide concentration of 3.3% by weight were placed in a sputtering device in this order from upstream to downstream in the conveyance direction of the transparent film substrate. Sputtering was then performed so that the thickness ratio of the first amorphous layer and the thickness ratio of the second amorphous layer in the amorphous transparent conductive layer were 95% and 5%, respectively. The amorphous transparent conductive layer included a first amorphous layer (tin oxide concentration of 10% by weight) and a second amorphous layer (tin oxide concentration of 3.3% by weight), arranged in this order toward one side in the thickness direction.

[0142] The argon partial pressure in the sputtering apparatus was adjusted to 0.35 Pa by adjusting the argon flow rate during sputtering. The pressure in the sputtering apparatus was 0.42 Pa.

[0143] In this way, an amorphous laminate film was produced which was provided with a transparent film, a hard coat layer, and an amorphous transparent conductive layer in this order.

[0144] Thereafter, the amorphous laminated film was heated at 130° C. for 90 minutes to crystallize the amorphous transparent conductive layer, thereby preparing a crystalline transparent conductive layer.

[0145] In this way, a transparent conductive film including a transparent film, a hard coat layer, and a crystalline transparent conductive layer was produced.

[0146] In addition, the crystalline transparent conductive layer included a first region and a second region respectively resulting from the first amorphous layer and the second amorphous layer.

[0147] Comparison Example 2 Comparison Example 3 and Comparative Example 1 A transparent conductive film was produced in the same manner as in Example 1, except that the thickness of the transparent substrate, the formulation of the hard coat composition, and the thickness of the transparent conductive layer were changed according to the description in Table 1. 2. Evaluation (Surface resistance) The surface resistivity of the transparent conductive layer of each example and each comparative example was measured by the four-terminal method in accordance with JIS K7194. The results are shown in Table 1.

[0148] (Flexural resistance) For each example and each comparative example, the transparent conductive film heat-treated at 165°C for 75 minutes was cut into a rectangular shape of 20 mm × 80 mm. Next, the short side of the rectangle was connected with a tester to observe the resistance value, and the transparent conductive film was bent so that the short side of the rectangle approached, with the transparent conductive layer on the outside, and the bending diameter (mm) of the transparent conductive film when the resistance value of the tester began to increase was measured. The results are shown in Table 1.

[0149] [Table 1] [Explanation of symbols]

[0150] 1 Transparent conductive film 2 Transparent substrate 3 Cured resin layer 4 Transparent conductive layer

Claims

1. A transparent conductive film comprising, in order, a transparent substrate, a cured resin layer, and a transparent conductive layer, wherein the thickness of the transparent conductive layer is 55 nm or more, the cured resin layer contains silica particles, the bending diameter measured by the following flexibility test is 10 mm or less, and the thickness of the cured resin layer is 0.5 μm or more and 10 μm or less. Flexibility test: Cut a transparent conductive film heat-treated at 165°C for 75 minutes into a rectangular shape of 20 mm × 80 mm. Next, connect the short side of the rectangle with a tester and observe the resistance value. Bend the transparent conductive film so that the short side of the rectangle approaches while keeping the transparent conductive layer on the outside, and measure the bending diameter (mm) of the transparent conductive film when the resistance value of the tester begins to increase.

2. The transparent conductive film according to claim 1, wherein the surface resistance value of the transparent conductive layer is 45 Ω / sq or less.

3. The transparent conductive film according to claim 1 or 2, wherein the thickness of the transparent substrate is 45 μm or less.

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