JP2018022634A - Transparent conductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductor that has both of excellent transparency and excellent conductivity, and also has excellent corrosion resistance under a high-temperature and high-humidity environment.SOLUTION: A transparent conductor 100 has a transparent resin base material 10, a first metal oxide layer 12, a metal layer 16 containing a silver alloy, and a second metal oxide layer 14 in the stated order. A surface 14a of the second metal oxide layer 14 has an arithmetic mean roughness Ra of 13 nm or less, and a maximum height Rz of 25 nm or more.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a transparent conductor.

The transparent conductor is used as a transparent electrode for a display such as a liquid crystal display (LCD), a plasma display panel (PDP), and an electroluminescence panel (organic EL, inorganic EL), and a solar cell. In addition to these, they are also used for electromagnetic wave shielding films and infrared ray prevention films. As a material for the metal oxide layer in the transparent conductor, ITO in which tin (Sn) is added to indium oxide (In ₂ O ₃ ) is widely used.

  The transparent conductor is required to be excellent in various properties depending on the use in addition to transparency. Moreover, the thing of various materials is examined as a transparent conductor excellent in electroconductivity than ITO. For example, Patent Document 1 proposes a transparent conductive film having a laminated structure of a metal oxide layer mainly composed of indium oxide or zinc oxide and a metal layer.

JP 2002-157929 A

  Transparent conductors having both transparency and conductivity are used in various applications. The transparent conductor may be used in a high-temperature and high-humidity environment such as a solar cell, an outdoor display, and a vehicle-mounted touch panel. However, when a transparent conductor having a metal layer and a pair of metal oxide layers sandwiching the metal layer is used for a long time in a high temperature and high humidity environment, corrosion may occur due to migration of the metal layer. . For this reason, there is a demand for a technique for improving the corrosion resistance of a transparent conductor while having excellent transparency and excellent conductivity.

  Therefore, an object of the present invention is to provide a transparent conductor having both excellent transparency and excellent conductivity and excellent corrosion resistance in a high temperature and high humidity environment.

  In one aspect, the present invention provides a transparent conductor comprising a transparent resin substrate, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer in this order, A transparent conductor having an arithmetic average roughness Ra of 13 nm or less and a maximum height Rz of 25 nm or more on the surface of the metal oxide layer 2 is provided.

  A transparent conductor comprising a transparent resin substrate, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer in this order is a transparent conductor composed of a conventional ITO film. In comparison, the overall thickness tends to increase. For this reason, the stress which arises in a transparent conductor becomes large, and the adhesiveness between each layer tends to fall. Here, it is conceivable to increase the surface roughness as a means for improving the adhesion. However, when the surface roughness is simply increased, there is a concern that the in-plane uniformity of the metal layer is particularly lowered and the structure is scattered in islands. If it becomes such a structure, transparency and electroconductivity will be impaired. On the other hand, when the thickness of the metal layer is increased, the transparency is impaired.

  Therefore, the transparent conductor of the present invention employs Ra and Rz as indices of surface roughness, the arithmetic average roughness Ra on the surface of the second metal oxide layer is 13 nm or less, and the maximum height on the surface. The thickness Rz is 25 nm or more. In a transparent conductor comprising a transparent resin substrate, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer in this order, the surface roughness on the surface of the second metal oxide layer The thickness depends on the surface roughness of each layer on the transparent resin substrate side of the second metal oxide layer.

  Accordingly, when the arithmetic average roughness Ra on the surface of the second metal oxide layer is 13 nm or less, the arithmetic average roughness Ra of each layer including the metal layer becomes low, and thus the metal layers are scattered in an island shape. The structure is suppressed, and the layer structure of each layer including the metal layer can be stably maintained. Thereby, excellent transparency and excellent conductivity can be realized. Furthermore, when the maximum height Rz on the surface of the second metal oxide layer is 25 nm or more, the adhesion between the respective layers can be sufficiently increased. As a result, even when used for a long time in a high-temperature and high-humidity environment, the occurrence of migration or the like of the metal layer is suppressed, and the corrosion resistance can be improved.

  The thickness of the metal layer is preferably 25 nm or less. The above-described transparent conductor can sufficiently suppress the metal layer from being scattered in an island shape. Therefore, excellent conductivity can be maintained even if the thickness of the metal layer is reduced. For this reason, total light transmittance can be reduced and transparency can be further improved.

The SnO ₂ content of tin oxide in the first metal oxide layer is preferably lower than the content of the second metal oxide layer. When the content of tin oxide is reduced, corrosion of the metal layer containing the silver alloy can be suppressed. By reducing the SnO ₂ equivalent content of tin oxide in the first metal oxide layer, corrosion of the conductor pattern can be suppressed after the conductor pattern is formed.

The first metal oxide layer preferably contains zinc oxide, indium oxide, and titanium oxide. The first metal oxide layer contains zinc oxide, indium oxide, and titanium oxide, and includes four components of zinc oxide, indium oxide, titanium oxide, and tin oxide, respectively, ZnO, In ₂ O ₃ , TiO _2, and when converted to SnO _2, ZnO content to the sum of four components is 20 to 80 mol%, the content of _in 2 _{O 3} is 10~35mol%, the content of TiO ₂ is 5 to 15 mol%, and, SnO The content of ₂ may be 40 mol% or less. By having such a composition, all the characteristics of transparency, conductivity and corrosion resistance can be maintained at a higher level.

The second metal oxide layer preferably contains zinc oxide, indium oxide, titanium oxide, and tin oxide. The second metal oxide layer contains four components of zinc oxide, indium oxide, titanium oxide, and tin oxide, the content of ZnO is 20 to 50 mol%, and the content of In ₂ O ₃ with respect to the total of the four components. 20～35Mol%, the content of TiO ₂ is 10 to 20%, and the content of SnO ₂ may be a 12~40mol%. By having such a composition, it is possible to maintain etching properties and alkali resistance while maintaining all the properties of transparency, conductivity and corrosion resistance at a higher level.

  The thickness of the first metal oxide layer and the second metal oxide layer may be 20 to 60 nm. As a result, both transparency and corrosion resistance can be achieved at a higher level.

  The above-described transparent conductor may include a hard coat layer containing a filler between the transparent resin base material and the first metal oxide layer. The thickness of the hard coat layer may be 0.1 to 10 μm. By providing such a hard coat layer, it becomes easier to adjust the arithmetic average roughness Ra and the maximum height Rz on the surface of the second metal oxide layer.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding transparency and the outstanding electroconductivity, the transparent conductor excellent in the corrosion resistance in a high-temperature, high-humidity environment can be provided.

FIG. 1 is a cross-sectional view schematically showing one embodiment of a transparent conductor. FIG. 2 is a photograph showing an image when the surface of the second metal oxide layer of Example 5 is observed with an atomic force microscope. FIG. 3 is a cross-sectional view schematically showing a conventional transparent conductor. FIG. 4 is a photograph showing an image when the surface of the second metal oxide layer of the transparent conductor of Comparative Example 2 is observed with an atomic force microscope.

  Embodiments of the present invention will be described below in detail with reference to the drawings. However, the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratio of each layer is not limited to the illustrated ratio.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a transparent conductor. The transparent conductor 100 is a laminate in which a transparent resin base material 10, a hard coat layer 20, a first metal oxide layer 12, a metal layer 16, and a second metal oxide layer 14 are arranged in this order. It has a structure. The first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 in the transparent conductor 100 each have a concavo-convex structure derived from the concavo-convex structure in the main surface of the hard coat layer 20. Have

  “Transparent” in the present specification means that visible light is transmitted, and the light may be scattered to some extent. Regarding the degree of light scattering, the required level varies depending on the use of the transparent conductor 100. What has light scattering generally referred to as translucent is also included in the concept of “transparency” in this specification. The degree of light scattering is preferably small, and the transparency is preferably high. The total light transmittance of the entire transparent conductor 100 is, for example, 82% or more, preferably 85% or more, and more preferably 88% or more. This total light transmittance is a transmittance including diffuse transmitted light obtained using an integrating sphere, and is measured using a commercially available haze meter.

  In the transparent conductor 100, the Ra of the surface 14a opposite to the metal layer 16 side of the second metal oxide layer 14 is 13 nm or less, preferably 10 nm or less, from the viewpoint of sufficiently increasing the total light transmittance. More preferably, it is 9 nm or less. Ra of the surface 14a may be 1 nm or more, or 2 nm or more from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100.

  Rz of the surface 14a of the second metal oxide layer 14 is 25 nm or more, preferably 30 nm or more, more preferably from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100. 39 nm or more. Rz on the surface may be 200 nm or less or 170 nm or less from the viewpoint of sufficiently increasing the total light transmittance.

  FIG. 3 is a cross-sectional view schematically showing a conventional transparent conductor 200. The transparent conductor 200 is a laminate in which a transparent resin substrate 210, a hard coat layer 220, a first metal oxide layer 212, a metal layer 216, and a second metal oxide layer 240 are arranged in this order. It has a structure. Since the transparent conductor 200 has a larger Ra on the surface of the second metal oxide layer 240 than the transparent conductor 100 shown in FIG. 1, the adhesion between the layers is excellent, but the continuous metal layer 216 having a particularly small thickness is used. It is easy to form island-like structures due to loss of properties. For this reason, excellent transparency and conductivity cannot be obtained.

  On the other hand, Ra of the transparent conductor 100 shown in FIG. 1 is smaller than the transparent conductor 200 of FIG. For this reason, the continuity of the metal layer 216 is not easily impaired, and excellent transparency and excellent conductivity can be obtained. Moreover, since the transparent conductor 100 has Rz of the surface 14a of the second metal oxide layer 14 larger than a predetermined value, the adhesion between the layers can be maintained sufficiently high. Thereby, it is excellent in corrosion resistance under high temperature and high humidity. In addition, Ra in this specification is arithmetic mean roughness, and Rz is the maximum height. Ra and Rz are measured according to JIS B 0601-2001. Ra and Rz may be collectively referred to as surface roughness.

The second metal oxide layer 14 is a transparent layer containing an oxide and contains four components of zinc oxide, indium oxide, titanium oxide and tin oxide as main components. The 2nd metal oxide layer 14 can form the 2nd metal oxide layer 14 which has the outstanding electroconductivity and the outstanding transparency by including the said 4 component as a main component. Zinc oxide is, for example, ZnO, and indium oxide is, for example, In ₂ O ₃ . Titanium oxide is, for example, TiO ₂ , and tin oxide is, for example, SnO ₂ . The ratio of metal atoms to oxygen atoms in each of the metal oxides may deviate from the stoichiometric ratio. Further, another oxide having a different oxidation number may be included.

The second metal oxide layer 14 is zinc oxide, indium oxide, titanium oxide and tin oxide, when converted respectively _ZnO, the _In 2 O 3, TiO ₂ and _{SnO 2, ZnO, In 2 O} 3, TiO The content of SnO ₂ with respect to the total of ₂ and SnO ₂ is 12 to 40 mol%. By setting the content of SnO _{2 in} the above range, both high conductivity and excellent corrosion resistance in a high temperature and high humidity environment can be achieved. The content of SnO ₂ is preferably 16 to 38 mol%. When the content of SnO ₂ becomes too large, the transparency and the corrosion resistance of the silver alloy in a high temperature and high humidity environment tend to be impaired. Furthermore, when the content of SnO ₂ is increased, it is difficult to dissolve in an acid and etching tends to be difficult. On the other hand, when the content of SnO ₂ becomes too small, excellent conductivity tends to be impaired.

From the viewpoint of achieving both excellent transparency and excellent conductivity, the content of ZnO is preferably 20 to 50 mol%, and preferably 30 to 48 mol when converted to each oxide in the same manner as the content of tin oxide. % Is more preferable. From the viewpoint of achieving both excellent transparency and high conductivity, the content of In ₂ O ₃ is preferably 20 to 35 mol% when converted into each oxide in the same manner as the content of tin oxide. More preferably, it is -33 mol%. The content of titanium oxide is preferably 10 to ₂₀ mol% as TiO ₂ when converted to each oxide in the same manner as the content of tin oxide, from the viewpoint of achieving both high transparency and excellent corrosion resistance. More preferably, it is 12-16 mol%.

  The second metal oxide layer 14 has functions such as adjustment of optical characteristics, protection of the metal layer 16, securing of conductivity, etching property and alkali resistance. The second metal oxide layer 14 may contain a trace component or an unavoidable component different from the above four components as long as the function is not significantly impaired. However, from the viewpoint of forming the transparent conductor 100 having sufficiently high characteristics, it is preferable that the total ratio of the main components in the second metal oxide layer 14 is higher. The ratio is 95 mol% or more, for example, Preferably it is 97 mol% or more. The second metal oxide layer 14 may be composed of the above four components.

  The first metal oxide layer 12 is a transparent layer containing an oxide and contains, for example, three components of zinc oxide, indium oxide, and titanium oxide as main components. In some embodiments, four components obtained by adding tin oxide to these three components may be contained as a main component. However, it is not essential to contain tin oxide, and tin oxide may not be contained.

Zinc oxide is, for example, ZnO, and indium oxide is, for example, In ₂ O ₃ . Titanium oxide is, for example, TiO ₂ , and tin oxide is, for example, SnO ₂ . The ratio of metal atoms to oxygen atoms in each of the metal oxides may deviate from the stoichiometric ratio. Further, another oxide having a different oxidation number may be included.

The first metal oxide layer 12 is zinc oxide, indium oxide, titanium oxide and tin oxide, when converted respectively _ZnO, the _In 2 O 3, TiO ₂ and _{SnO 2, ZnO, In 2 O} 3, TiO The content of SnO ₂ with respect to the total of ₂ and SnO ₂ is preferably 40 mol% or less. Thus, by lowering the content of SnO ₂ , corrosion of the metal layer 16 in a high temperature and high humidity environment can be further suppressed. This is presumably because the reaction between Sn in the first metal oxide layer 12 and the silver alloy in the metal layer 16 can be suppressed. However, the mechanism of corrosion inhibition is not limited to this.

From the viewpoint of further suppressing migration of the metal layer 16 in a high temperature and high humidity environment, the content of SnO ₂ is preferably 20 mol% or less, and more preferably 5 mol% or less. When the content of SnO ₂ decreases, the conductivity of the first metal oxide layer 12 tends to decrease. However, the conductivity of the transparent conductor 100 may be borne by the metal layer 16 and the second metal oxide layer 14. The conductivity of the second metal oxide layer 14 can be improved by making the tin oxide content higher than that of the first metal oxide layer 12. Therefore, the first metal oxide layer 12 may have low conductivity or may be an insulator.

The content of the three components in the first metal oxide layer 12 may be in the following range. That is, from the viewpoint of achieving both excellent transparency and excellent conductivity, when zinc oxide, indium oxide and titanium oxide are converted into ZnO, In ₂ O ₃ and TiO ₂ , respectively, the ZnO content is 20 to 20%. It is preferably 80 mol%, and more preferably 30 to 78 mol%. From the viewpoint of achieving both excellent transparency, high electrical conductivity, and high corrosion resistance, the In ₂ O ₃ content may be 10 to 35 mol% when converted to each oxide in the same manner as the zinc oxide content. Preferably, it is 13-30 mol%. From the viewpoint of achieving both high transparency and excellent corrosion resistance, the content of TiO ₂ is preferably 5 to 15 mol%, and preferably 7 to 13 mol% when converted to each oxide in the same manner as the content of zinc oxide. It is more preferable that

  The first metal oxide layer 12 has functions such as adjustment of optical characteristics and protection of the metal layer 16. The first metal oxide layer 12 may contain a trace component or an unavoidable component different from the above four components as long as the function is not significantly impaired. However, from the viewpoint of making the transparent conductor 100 having sufficiently high characteristics, it is preferable that the total ratio of the main components in the first metal oxide layer 12 is higher. The ratio is 95 mol% or more, for example, Preferably it is 97 mol% or more. The first metal oxide layer 12 may be composed of the three components or the four components.

  From the viewpoint of sufficiently increasing the total light transmittance, Ra of the main surface of the first metal oxide layer 12 on the metal layer 16 side is preferably 13 nm or less, more preferably 10 nm or less, and still more preferably. 9 nm or less. Ra of the main surface may be 1 nm or more, or 2 nm or more from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100.

  Rz on the main surface opposite to the metal layer 16 side of the first metal oxide layer 12 is preferably 25 nm or more from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100. More preferably, it is 30 nm or more, and further preferably 39 nm or more. Rz of the main surface may be 200 nm or less or 170 nm or less from the viewpoint of sufficiently increasing the total light transmittance.

  The first metal oxide layer 12 and the second metal oxide layer 14 are preferably amorphous. Thereby, it is possible to further suppress water vapor from passing through the first metal oxide layer 12 and the second metal oxide layer 14. The first metal oxide layer 12 can be made amorphous by adjusting the composition, for example. The second metal oxide layer 14 can be made amorphous by adjusting the composition, for example.

  The first metal oxide layer 12 and the second metal oxide layer 14 may be the same or different in terms of thickness, structure, composition, and surface roughness. By making the composition of the first metal oxide layer 12 and the composition of the second metal oxide layer 14 different, only the second metal oxide layer 14 and the metal layer 16 are etched in one step. The first metal oxide layer 12 can be left as it is by removing.

  From the viewpoint of further improving the transparency, the thicknesses of the first metal oxide layer 12 and the second metal oxide layer 14 are, for example, 60 nm or less. On the other hand, from the viewpoint of further improving corrosion resistance and improving productivity, the thickness is, for example, 20 nm or more.

  The first metal oxide layer 12 and the second metal oxide layer 14 can be manufactured by a vacuum film formation method such as a vacuum evaporation method, a sputtering method, an ion plating method, or a CVD method. Among these, the sputtering method is preferable in that the film forming chamber can be downsized and the film forming speed is high. Examples of the sputtering method include DC magnetron sputtering. As a target, an oxide target, a metal, or a metalloid target can be used.

A wiring electrode or the like may be provided on the second metal oxide layer 14. A current that conducts through a metal layer 16 to be described later is supplied from the wiring electrode or the like provided on the second metal oxide layer 14 via the second metal oxide layer 14 to the second metal oxide layer 14. It is led to another wiring electrode provided on the top. For this reason, it is preferable that the 2nd metal oxide layer 14 has high electroconductivity. From such a viewpoint, the surface resistance value of the second metal oxide layer 14 single layer is, for example, 1.0 × 10 ⁺⁷ Ω / sq. Or less, preferably 5.0 × 10 ⁺⁶ Ω / sq. The following is more preferable.

  The metal layer 16 is a layer containing a silver alloy as a main component. Since the metal layer 16 has high transparency and conductivity, the surface resistance can be sufficiently lowered while sufficiently increasing the total light transmittance of the transparent conductor 100. Examples of the constituent element of the silver alloy include Ag and at least one selected from Pd, Cu, Nd, In, Sn, and Sb. Examples of silver alloys include Ag-Pd, Ag-Cu, Ag-Pd-Cu, Ag-Nd-Cu, Ag-In-Sn, and Ag-Sn-Sb. The silver alloy preferably contains Ag as a main component and includes the above-described metals as subcomponents.

  Content of metals other than silver is 0.5-5 mass% on the basis of the metal layer 16, from a viewpoint of improving corrosion resistance and transparency further, for example. The silver alloy preferably contains Pd as a metal other than silver. Thereby, the corrosion resistance in a high-temperature and high-humidity environment can be further improved. The content of Pd in the silver alloy may be, for example, 1% by mass or more.

  The thickness of the metal layer 16 may be 25 nm or less, for example. In the transparent conductor 100, since the Ra of the second metal oxide layer is sufficiently small, even when the metal layer 16 has the above-described thickness, the island-like structure is suppressed, and the transparent conductor 100 The total light transmittance and conductivity can be made sufficiently high. However, if the thickness of the metal layer 16 becomes too small, the continuity of the metal layer 16 tends to be impaired and an island structure tends to be easily formed. For this reason, the thickness of the metal layer 16 may be 4 nm or more.

  The metal layer 16 has a function of adjusting the total light transmittance and surface resistance of the transparent conductor 100. The metal layer 16 can be produced by a vacuum film forming method such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. Among these, the sputtering method is preferable because the film forming chamber can be downsized and the film forming speed is high. Examples of the sputtering method include DC magnetron sputtering. A metal target can be used as the target.

  Ra of the main surface of the metal layer 16 on the second metal oxide layer 14 side is preferably 13 nm or less, more preferably 10 nm or less, and still more preferably, from the viewpoint of sufficiently increasing the total light transmittance. 9 nm or less. Ra of the main surface may be 1 nm or more, or 2 nm or more from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100.

  Rz of the main surface of the metal layer 16 on the second metal oxide layer 14 side is preferably 25 nm or more, more preferably from the viewpoint of sufficiently increasing the adhesion between the layers constituting the transparent conductor 100. It is 30 nm or more, more preferably 39 nm or more. Rz of the main surface may be 200 nm or less or 170 nm or less from the viewpoint of sufficiently increasing the total light transmittance.

  At least a part of the second metal oxide layer 14 and at least a part of the metal layer 16 in the transparent conductor 100 may be removed by etching or the like. In this case, a conductor pattern is formed by the metal layer 16 and the second metal oxide layer 14. At least a part of the first metal oxide layer 12 may also be removed by etching or the like.

  The hard coat layer 20 contains, for example, a cured resin obtained by curing a resin composition and a filler dispersed in the cured resin. The resin composition preferably contains at least one selected from a thermosetting resin composition, an ultraviolet curable resin composition, and an electron beam curable resin composition. The thermosetting resin composition may include at least one selected from an epoxy resin, a phenoxy resin, and a melamine resin.

  A resin composition is a composition containing the sclerosing | hardenable compound which has energy-beam reactive groups, such as a (meth) acryloyl group and a vinyl group, for example. Note that the notation of (meth) acryloyl group includes at least one of acryloyl group and methacryloyl group. The curable compound preferably contains a polyfunctional monomer or oligomer containing 2 or more, preferably 3 or more energy ray reactive groups in one molecule.

  The curable compound preferably contains an acrylic monomer. Specific examples of acrylic monomers include 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, ethylene oxide-modified bisphenol A di (meth) acrylate, and trimethylolpropane tri (meth). Acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, trimethylolpropane propylene oxide modified tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta (meth) Acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, and 3- (meth) acryloyloxy Riserinmono (meth) acrylate. However, it is not necessarily limited to these. For example, urethane-modified acrylate and epoxy-modified acrylate are also included.

  As the curable compound, a compound having a vinyl group may be used. Examples of the compound having a vinyl group include ethylene glycol divinyl ether, pentaerythritol divinyl ether, 1,6-hexanediol divinyl ether, trimethylolpropane divinyl ether, ethylene oxide-modified hydroquinone divinyl ether, ethylene oxide-modified bisphenol A divinyl ether, Examples include pentaerythritol trivinyl ether, dipentaerythritol hexavinyl ether, and ditrimethylolpropane polyvinyl ether. However, it is not necessarily limited to these.

  The resin composition contains a photopolymerization initiator when the curable compound is cured by ultraviolet rays. Various photopolymerization initiators can be used. For example, it may be appropriately selected from known compounds such as acetophenone, benzoin, benzophenone, and thioxanthone. More specifically, Darocur 1173, Irgacure 651, Irgacure 184, Irgacure 907 (above trade name, manufactured by Ciba Specialty Chemicals) and KAYACURE DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) can be mentioned. .

  A photoinitiator should just be about 0.01-20 mass% or about 0.5-5 mass% with respect to the mass of a curable compound. The resin composition may be a known composition obtained by adding a photopolymerization initiator to an acrylic monomer. Examples of the acrylic monomer added with a photopolymerization initiator include SD-318 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.) and XNR5535 (trade name, Nagase Sangyo), which are ultraviolet curable resins. Etc.).

  When a resin composition that cures with energy rays is used, the resin composition can be cured by irradiation with energy rays such as ultraviolet rays. Accordingly, it is preferable to use such a resin composition from the viewpoint of the manufacturing process.

  Examples of the filler include organic fillers and inorganic fillers. Examples of the organic filler include organic silicon compound particles, crosslinked acrylic particles, and crosslinked polystyrene particles. Examples of the inorganic filler include silicon oxide particles, aluminum oxide particles, zirconium oxide particles, titanium oxide particles, and iron oxide particles. The surface of the filler may be treated with a silane coupling agent, and an energy ray reactive group such as a (meth) acryloyl group and / or a vinyl group may be formed in a film shape on the surface.

  The average particle diameter of the filler is smaller than the thickness of the hard coat layer 20, and may be 200 nm or less or 150 nm or less from the viewpoint of ensuring sufficient transparency. From the viewpoint of sufficiently increasing the Rz of the second metal oxide layer 14, the average particle size of the filler is preferably 10 nm or more, and more preferably 30 nm or more.

  The average particle diameter of the filler can be determined as follows in the observation image of the cross section of the hard coat layer 20 using a transmission electron microscope. In the observation image, 100 fillers are arbitrarily selected. The diameter of a perfect circle having the same area is determined for each selected filler. The arithmetic average value of the obtained diameter is obtained. The arithmetic average value thus obtained is taken as the average particle size of the filler.

  The content of the filler in the hard coat layer 20 is preferably 2% by volume or more, more preferably 4% by volume or more, from the viewpoint of sufficiently increasing Rz. The filler content in the hard coat layer 20 is preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoint of sufficiently reducing Ra.

  The hard coat layer 20 can be produced by applying a paint (dispersion) containing a solvent, a resin composition, and a filler on one surface of the transparent resin substrate 10 and drying it to cure the resin composition. . Application | coating in this case can be performed by a well-known method. Examples of the coating method include an extrusion nozzle method, a blade method, a knife method, a bar coating method, a kiss coating method, a kiss reverse method, a gravure roll method, a dip method, a reverse roll method, a direct roll method, a curtain method, and a squeeze method. Etc.

  The solid content concentration in the paint is, for example, 5 to 40% by mass based on the solvent. The thickness of the hard coat layer 20 can be adjusted by changing the solid content concentration. The solid content concentration is a mass ratio of the solid content to the solvent, and the solid content includes a filler and a resin composition. A normal organic solvent can be used as the solvent.

  The thickness of the hard coat layer 20 is, for example, 0.1 to 10 μm, and preferably 0.5 to 5 μm. This makes it easier to adjust the arithmetic average roughness Ra and the maximum height Rz on the surface of the second metal oxide layer 14. On the other hand, when the thickness exceeds 10 μm, uneven thickness or wrinkles tend to occur.

  The refractive index of the hard coat layer 20 is, for example, 1.40 to 1.60. The absolute value of the difference in refractive index between the transparent resin substrate 10 and the hard coat layer 20 is preferably 0.1 or less.

  The hard coat layer 20 can increase the surface Rz of the second metal oxide layer 14 by decreasing the thickness while increasing the particle size of the filler. Moreover, Ra of the surface of the second metal oxide layer 14 can be reduced by reducing the filler content in the hard coat layer 20 (the particle diameter is constant). On the contrary, Ra on the surface of the second metal oxide layer 14 can be increased by increasing the filler content in the hard coat layer 20 (the particle size is constant). For example, when the filler particle size is increased while maintaining the filler content in the hard coat layer 20, the number of fillers is reduced, so that Rz can be increased without significantly changing Ra.

  In this manner, by adjusting the particle size and content of the filler and the thickness of the hard coat layer 20, Ra and Rz of the surface 14 a of the second metal oxide layer 14 can be adjusted to a desired range. it can. The thickness of the hard coat layer 20 can be adjusted by changing the coating amount of the paint for forming the hard coat layer 20 and the content ratio of the solvent in the paint.

  The transparent resin substrate 10 is not particularly limited, and may be a flexible organic resin film. The organic resin film may be an organic resin sheet. Examples of organic resin films include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polycarbonate films, acrylic films, norbornene films, polyarylate films, and polyether sulfone films. , A diacetyl cellulose film, a triacetyl cellulose film, and the like. Of these, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferable.

  The transparent resin base material 10 is preferably thicker from the viewpoint of rigidity. On the other hand, the transparent resin substrate 10 is preferably thin from the viewpoint of thinning the transparent conductor 100. From such a viewpoint, the thickness of the transparent resin substrate 10 is, for example, 20 to 200 μm. The refractive index of the transparent resin substrate is, for example, 1.50 to 1.70 from the viewpoint of a transparent conductor excellent in optical characteristics. The refractive index in this specification is a value measured under the conditions of λ = 633 nm and a temperature of 20 ° C.

  The transparent resin substrate 10 may be subjected to at least one surface treatment selected from the group consisting of corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, and ozone treatment. Good. By such surface treatment, the surface roughness of the transparent resin substrate 10 can be adjusted.

  Ra of the surface of the transparent resin substrate 10 may be, for example, 20 nm or less, or 4 to 10 nm. Rz of the transparent resin substrate 10 may be, for example, 50 nm or more, or 100 to 300 nm. If the surface Ra and Rz are the transparent resin base material 10 in the above range, the Ra and Rz of the second metal oxide layer 14 can be easily adjusted to a desired range.

  When the transparent resin substrate 10 is an organic resin film, the transparent conductor 100 can be made excellent in flexibility. Thereby, it can be used more suitably for transparent conductors for touch panel applications, transparent electrodes for organic devices such as flexible organic EL lighting, and electromagnetic wave shields.

  The thickness of each layer constituting the transparent conductor 100 can be measured by the following procedure. The transparent conductor 100 is cut by a focused ion beam device (FIB, Focused Ion Beam) to obtain a cross section. The cross section is observed using a transmission electron microscope (TEM), and the thickness of each layer is measured. The measurement is preferably performed at 10 or more arbitrarily selected positions, and the average value is obtained. As a method for obtaining the cross section, a microtome may be used as an apparatus other than the focused ion beam apparatus. As a method for measuring the thickness, a scanning electron microscope (SEM) may be used. It is also possible to measure the film thickness using a fluorescent X-ray apparatus.

  The thickness of the transparent conductor 100 may be 300 μm or less, or 250 μm or less. Such a thickness can sufficiently satisfy the required level of thinning. The total light transmittance of the transparent conductor 100 can be as high as 82% or more, for example. Moreover, the transparent conductor 100 is excellent also in electroconductivity. For example, the surface resistance value (4-terminal method) is 30 Ω / sq. Even without thermal annealing of the first metal oxide layer 12 and the second metal oxide layer 14. It can be:

  The transparent conductor 100 having the above-described configuration has a stacked structure in which the first metal oxide layer 12, the metal layer 16, and the second metal oxide layer 14 are stacked. This laminated structure can be easily removed at once using a normal etching solution (acid). Moreover, it is excellent also in alkali tolerance. Therefore, patterning can be formed efficiently. The transparent conductor 100 is used for transparent electrodes, for antistatic purposes, and for electromagnetic wave shielding in various display devices such as organic EL displays, organic EL lighting, organic thin film solar cells, and other display devices such as light control films and electronic paper. Can do.

  The surface resistance value of the transparent conductor in the above-mentioned application is approximately 30Ω / sq. The following is preferable. Conventionally, an ITO film having a thickness of 100 nm or more has been used as a transparent electrode, but it has been difficult to sufficiently reduce the surface resistance on a resin substrate. However, the transparent conductor 100 can be made lower in surface resistance than ITO having the above-mentioned thickness, and is suitably used as a transparent electrode for applications that are required to have a low surface resistance on a resin substrate. It is done. The transparent conductor 100 can also be used for a liquid crystal screen and an antenna. The transparent conductor 100 can also be used as a negative electrode of an organic device.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment. For example, the above-described transparent conductor 100 has the hard coat layer 20, but may not have the hard coat layer 20. In this case, for example, Ra and Rz of the second metal oxide layer 14 can be adjusted to a desired range by changing the surface roughness of the transparent resin substrate 10 by surface treatment. Moreover, the transparent conductor may have the hard-coat layer 20 on the opposite side to the 2nd metal oxide layer 14 side of the transparent resin base material 10. FIG.

  In another some embodiment, you may provide a pair of hard-coat layer so that the transparent resin base material 10 may be pinched | interposed. The thickness and composition of the pair of hard coat layers may be the same or different. Furthermore, the transparent conductor may have an arbitrary layer at an arbitrary position in addition to the above-mentioned layer as long as the function is not greatly impaired.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Example 1]
(Production of transparent conductor)
A transparent conductor as shown in FIG. 1 was produced. The transparent conductor had a laminated structure in which a transparent resin base material, a hard coat layer, a first metal oxide layer, a metal layer, and a second metal oxide layer were laminated in this order. This transparent conductor was produced as follows.

A commercially available polyethylene terephthalate film (thickness: 125 μm, Ra: 5.7 nm, Rz: 260 nm) was prepared. This PET film was used as a transparent resin substrate. A hard coat layer was formed on the PET film. The hard coat layer was formed by applying and drying a paint containing a filler (SiO ₂ particles), a resin composition and a solvent, followed by curing with ultraviolet irradiation. Table 1 shows the thickness of the hard coat layer, and the filler material and average particle size contained in the hard coat layer. Moreover, solid content concentration (mass ratio of the solid content with respect to the sum total of a solvent and solid content) in a coating material was as showing in Table 1.

A first metal oxide layer, a metal layer, and a second metal oxide layer were sequentially formed on the hard coat layer by DC magnetron sputtering. The first metal oxide layer was composed of three components of zinc oxide, indium oxide, and titanium oxide. In the first metal oxide layer, when zinc oxide, indium oxide, and titanium oxide are converted into ZnO, In ₂ O ₃ , and TiO ₂ , respectively, the content of ZnO with respect to the total of the above three components Was 77 mol%, the content of In ₂ O ₃ was 14 mol%, and the content of TiO ₂ was 9 mol%.

The second metal oxide layer was composed of four components of zinc oxide, indium oxide, titanium oxide, and tin oxide. In the second metal oxide layer, when zinc oxide, indium oxide, titanium oxide and tin oxide are converted into ZnO, In ₂ O ₃ , TiO ₂ and SnO ₂ respectively, The content was 35 mol%, the content of In ₂ O ₃ was 29 mol%, the content of TiO ₂ was 14 mol%, and the content of SnO ₂ was 22 mol%. The thickness of the first metal oxide layer and the second metal oxide layer was 40 nm.

  The metal layer was composed of Ag, Pd, and Cu, and the mass ratio was Ag: Pd: Cu = 99.0: 0.7: 0.3. The thickness of the metal layer was 10 nm.

(Evaluation of transparent conductor)
The arithmetic average roughness Ra and the maximum height Rz of the surface of the second metal oxide layer of the produced transparent conductor were measured. The measurement was performed in a 10 μm square region arbitrarily selected using a commercially available atomic force microscope (NanoScope 3 manufactured by Digital Instruments). The measurement results were as shown in Table 1.

  The produced transparent conductor was subjected to a cross-cut test to evaluate the adhesion between the layers. The cross cut test was performed in accordance with JIS K 5600. Specifically, eleven notches were made in the surface of the second metal oxide layer along the vertical and horizontal directions at intervals of 1 mm to form 100 square grids. Thereafter, a cellophane tape was attached to the cut area. The affixed cellophane tape was peeled off, the peeling state at 100 squares was visually confirmed, and the results were classified into 6 stages of 5B, 4B, 3B, 2B, 1B, and 0B. The case where there was no peeling at all was classified as “5B”, and the case where the ratio of the peeled area was the highest was classified as “0B”. The measurement results were as shown in Table 1.

  The total light transmittance (transmittance) and haze value of the produced transparent conductor were measured using a haze meter (trade name: NDH-7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The measurement results were as shown in Table 1.

  The surface resistance value of the produced transparent conductor was measured using a 4-terminal resistivity meter (trade name: Loresta GP, manufactured by Mitsubishi Chemical Corporation). The results are shown in the “resistance value” column of Table 1.

  The corrosion resistance of the produced transparent conductor was evaluated by the following procedure. Specifically, the transparent conductor was stored for 50 hours in an environment of 85 ° C. and 85% RH (relative humidity 85%). After storage, the surface of the transparent conductor on the second metal oxide layer side was visually observed. The case where no defect was visually observed was evaluated as “A”, and the case where a defect was observed was evaluated as “B”. The results are as shown in the column of “Corrosion resistance” in Table 1.

  The crystallinity of the first metal oxide layer and the second metal oxide layer in the produced transparent conductor was evaluated using XRD. As a result, in both the first metal oxide layer and the second metal oxide layer, no diffraction peak was observed when the diffraction angle (2θ) according to the X-ray diffraction method was 20 to 60 °. Therefore, it was confirmed that the first metal oxide layer and the second metal oxide layer were amorphous.

[Example 2]
A transparent conductor was prepared and evaluated in the same manner as in Example 1 except that the hard coat layer was formed using a paint containing a filler having an average particle size shown in Table 1. The evaluation results are shown in Table 1. For the hard coat layer of Example 2, a paint containing a filler having an average particle size larger than that of Example 1 was used. For this reason, Ra and Rz were larger in Example 2 than in Example 1.

[Example 3]
As shown in Table 1, a transparent conductor was prepared and evaluated in the same manner as in Example 2 except that the thickness of the hard coat layer was changed by using paints having different solid content concentrations. The evaluation results are shown in Table 1.

[Example 4]
As shown in Table 1, Example 1 except that the hard coat layer was formed using a paint containing ZrO ₂ particles instead of SiO ₂ particles as shown in Table 1, and the thickness of the hard coat layer was changed. Similarly, a transparent conductor was produced and evaluated. The evaluation results are shown in Table 1. In Example 4, since the thickness of the hard coat layer was smaller than in Examples 1 to 3, Rz was large. On the other hand, since the average particle diameter of the filler was smaller than Examples 1-3, Ra was small.

[Example 5]
A transparent conductor was prepared and evaluated in the same manner as in Example 4 except that the hard coat layer was formed using paints having different solid content concentrations. The hard coat layer of Example 5 had a lower solid content concentration (filler content) than the hard coat layer of Example 4. For this reason, in Example 5, the thickness of the hard coat was thinner than in Example 4, and Ra and Rz were larger. The evaluation results are shown in Table 1.

[Comparative Example 1]
A transparent conductor was prepared and evaluated in the same manner as in Example 1 except that the hard coat layer was not provided. The evaluation results are shown in Table 2.

[Comparative Example 2]
As shown in Table 2, a transparent conductor was produced and evaluated in the same manner as in Example 2 except that the thickness of the hard coat layer was changed by using paints having different solid content concentrations. The evaluation results are shown in Table 2. Since the solid content concentration was smaller than in Example 2, the amount of solvent volatilized from the coating after application increased, and the thickness of the hard coat layer formed was small. For this reason, it is thought that Ra and Rz became larger than Example 2 because the filler exposed in the hard coat layer increased and the surface unevenness increased.

[Comparative Example 3]
As shown in Table 2, a transparent conductor was produced and evaluated in the same manner as in Example 5 except that the hard coat layer was formed using a paint having a solid content concentration higher than that in Example 5. The evaluation results are shown in Table 2. Since the solid content concentration was higher than that in Example 5, the amount of solvent volatilized from the paint after application was reduced, and the thickness of the hard coat layer formed was increased. For this reason, it is thought that Ra and Rz became smaller than Example 5 because the filler was embedded in the cured resin to reduce the surface irregularities.

[Comparative Example 4]
A commercially available polyethylene terephthalate film (thickness: 125 μm, Ra: 1.2 nm, Rz: 22.6 nm) was prepared. This PET film was used as a transparent resin substrate. A SiO ₂ layer and an ITO (tin-doped indium oxide) layer were sequentially formed on the PET film by DC magnetron sputtering. The obtained laminate was heated at 140 ° C. for 60 minutes to crystallize ITO. In this way, a transparent conductor of Comparative Example 4 was obtained. The thickness of the SiO ₂ layer was 5 nm, and the thickness of the ITO layer was 25 nm. In the same manner as in Example 1, the obtained transparent conductor was evaluated. The evaluation results are shown in Table 2.

[Comparative Example 5]
Comparative Example 4 except that a hard coat layer was formed on the PET film using the same paint as in Example 1, and an SiO ₂ layer and an ITO (tin-doped indium oxide) layer were sequentially formed on the hard coat layer. A transparent conductor was prepared in the same manner as described above and evaluated. The evaluation results are shown in Table 2.

[Comparative Example 6]
A transparent conductor was produced and evaluated in the same manner as in Comparative Example 5 except that a hard coat layer was formed on the PET film using the same paint as in Comparative Example 2. The evaluation results are shown in Table 2.

  As shown in Table 1, the evaluation of the cross-cut adhesion of the transparent conductors of Examples 1 to 5 was a better result than 3B or 3B. For this reason, it was excellent in corrosion resistance under high temperature and high humidity. Moreover, the total light transmittance of the transparent conductor of Examples 1-5 was 82% or more, and the haze value was 1.0% or less, and it had the outstanding transparency. Furthermore, the resistance values of the transparent conductors of Examples 1 to 5 were 30 Ω / sq. It was the following and was excellent also in electroconductivity. On the other hand, as shown in Table 2, Comparative Examples 1 and 3 were inferior to Examples 1-5 from the result of the crosscut test. For this reason, the corrosion resistance under high temperature and high humidity was also inferior. In Comparative Example 2, although the result of the crosscut test was good, the total light transmittance was low.

  FIG. 2 is a photograph showing an observation image of the surface of the second metal oxide layer of the transparent conductor of Example 5 using an atomic force microscope. FIG. 4 is a photograph showing an observation image of the surface of the second metal oxide layer of the transparent conductor of Comparative Example 2. As is clear from the comparison between FIG. 2 and FIG. 4, Example 5 had fewer irregularities than Comparative Example 2. However, the maximum peak height was higher in Example 5 than in Comparative Example 2.

[Examples 6 and 7]
A transparent conductor was prepared and evaluated in the same manner as in Example 1 except that the thickness of the metal layer was changed as shown in Table 3. The evaluation results are shown in Table 3. For comparison, the evaluation results of Example 1 are also shown in Table 3.

  From the comparison between Example 1 and Example 6, there was a tendency that the resistance value increased as the thickness of the metal layer decreased. This is considered to be because the stability of the layer structure is improved by increasing the thickness of the metal layer. In addition, from the comparison between Example 1 and Example 7, when the thickness of the metal layer was increased, the total light transmittance tended to decrease. By changing the thickness of the metal layer, the total light transmittance and the resistance value can be adjusted.

  According to the present disclosure, a transparent conductor having both excellent transparency and excellent conductivity and excellent corrosion resistance in a high-temperature and high-humidity environment is provided.

  DESCRIPTION OF SYMBOLS 10,210 ... Transparent resin base material, 12,212 ... 1st metal oxide layer, 14,240 ... 2nd metal oxide layer, 14a ... Surface, 16,216 ... Metal layer, 20,220 ... Hard coat Layer, 100, 200 ... Transparent conductor.

Claims (9)

A transparent conductor comprising a transparent resin substrate, a first metal oxide layer, a metal layer containing a silver alloy, and a second metal oxide layer in this order,
A transparent conductor having an arithmetic average roughness Ra of 13 nm or less and a maximum height Rz of 25 nm or more on the surface of the second metal oxide layer.   The transparent conductor according to claim 1, wherein the metal layer has a thickness of 25 nm or less. The transparent conductor according to claim 1 or 2, wherein a content of tin oxide in terms of SnO ₂ in the first metal oxide layer is lower than the content in the second metal oxide layer.   The said 1st metal oxide layer is a transparent conductor as described in any one of Claims 1-3 containing a zinc oxide, an indium oxide, and a titanium oxide. The first metal oxide layer contains zinc oxide, indium oxide, and titanium oxide, and four components of zinc oxide, indium oxide, titanium oxide, and tin oxide are ZnO, In ₂ O ₃ , and TiO ₂ , respectively. and when converted to SnO _2, the content of ZnO to the total of 4 components 20~80mol%, 10~35mol% content of _in 2 _{O 3,} TiO ₂ content 5 to 15 mol%, and , the content of SnO ₂ is less than 40 mol%, the transparent conductor according to any one of claims 1-4.   6. The transparent conductor according to claim 1, wherein the second metal oxide layer contains zinc oxide, indium oxide, titanium oxide, and tin oxide. The second metal oxide layer contains four components of zinc oxide, indium oxide, titanium oxide and tin oxide,
The content of ZnO to the total of 4 components 20~50mol%, 20~35mol% content of _{an In} 2 _{O 3,} TiO ₂ content 10 to 20%, and the content of SnO ₂ is 12 The transparent conductor according to any one of claims 1 to 6, which is 40 mol%.   The transparent conductor as described in any one of Claims 1-7 whose thickness of a said 1st metal oxide layer and a said 2nd metal oxide layer is 20-60 nm. A hard coat layer containing a filler is provided between the transparent resin substrate and the first metal oxide layer,
The transparent conductor according to claim 1, wherein the hard coat layer has a thickness of 0.1 to 10 μm.