JP2016081210A - Conductive laminate and touch panel prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive laminate using carbon nanotubes as conductive material, the conductive laminate having a sufficiently small reflectance of a conductive layer surface.SOLUTION: A conductive laminate has, on at least one side of a base material, an undercoat layer, a carbon nanotubes layer and an overcoat layer stacked in order from the base material side, with the undercoat layer having a refractive index of 1.40 or less, and the overcoat layer having a refractive index of 1.43 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive laminate using carbon nanotubes as a conductive material, and a touch panel using the same.

  In order to drive a touch panel mounted on a portable device, a tablet terminal, or the like, a conductive laminate (conductive film) is used.

  As a conductive material used for the conductive layer constituting the conductive laminate, metal oxides such as indium oxide doped with tin oxide (ITO) and antimony / tin oxide (ATO), metals such as silver and copper Nanowires and carbon nanotubes are known.

  Development of a conductive laminate using carbon nanotubes as a conductive material is in progress. Conductive layers composed of carbon nanotubes can be wet-coated, and can be manufactured by a simple process. Since carbon nanotubes are highly flexible, they can be bent by providing a conductive layer composed of carbon nanotubes on a flexible substrate. There is an advantage that a conductive laminate having excellent properties can be obtained.

  In the conductive laminate using carbon nanotubes, in order to increase the transmittance of the conductive laminate, it has been proposed to reduce the reflectance of the surface of the conductive laminate (Patent Documents 1 and 2).

  Moreover, providing an undercoat layer between a base material and a carbon nanotube layer is proposed (patent documents 3-5).

JP 2010-192186 A JP 2012-66580 A JP 2011-103231 A JP 2014-29831 A JP 2014-60158 A

  When the conductive laminate is applied to the touch panel, if the reflectance of the conductive layer surface of the conductive laminate is high, the surface of the conductive laminate (conductive layer surface) and the air due to the presence of the space (air layer) inside the touch panel In some cases, the interface reflection with the layer becomes large, which may cause a disadvantage that the touch panel transparency of a light emitting image emitted from an image display panel such as a liquid crystal is lowered.

  Accordingly, an object of the present invention is to provide a conductive laminate using a carbon nanotube as a conductive material, and a conductive laminate in which the reflectance of the surface of the conductive layer is sufficiently reduced, and a touch panel using the same. is there.

The above object of the present invention has been basically achieved by the following invention.
[1] A conductive laminate in which an undercoat layer, a carbon nanotube layer, and an overcoat layer are laminated in order from the substrate side on at least one surface of the substrate, and the refractive index of the undercoat layer is 1. A conductive laminate having a refractive index of 40 or less and an overcoat layer of 1.43 or less.
[2] The conductive laminate according to [1], wherein the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat layer is 75 to 125 nm.
[3] The conductive laminate according to [1] or [2], wherein the base material has a refractive index of 1.61 to 1.70.
[4] The conductive laminate according to [3], wherein the substrate is a polyethylene terephthalate film.
[5] The conductive laminate according to [4], having a resin layer having a refractive index of 1.55 to 1.70 between the base material and the undercoat layer.
[6] The conductive laminate according to [5], wherein the resin layer has a refractive index of 1.61 to 1.70.
[7] A touch panel using the conductive laminate according to any one of [1] to [6].

  According to the present invention, it is possible to provide a conductive laminate having a sufficiently low reflectance. Moreover, the touch panel using the electroconductive laminated body of this invention can suppress the fall of the touch panel transparency of the luminescent image emitted from the image display panel.

FIG. 1 is a schematic cross-sectional view showing an example of a touch panel using the conductive laminate of the present invention.

  The conductive laminate according to the present invention is a conductive laminate in which an undercoat layer, a carbon nanotube layer, and an overcoat layer are laminated in order from the substrate side on at least one surface of the substrate. The characteristic structure of the laminate is that the refractive index of the undercoat layer is 1.40 or less, and the refractive index of the overcoat layer is 1.43 or less.

  The conductive laminate according to the present invention can reduce the reflectance of the surface of the conductive laminate by combining the above-described characteristic configurations.

  In the conductive laminate according to the present invention, the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat layer is preferably 75 to 125 nm, more preferably 80 to 120 nm, and 85 to 115 nm. It is particularly preferred. Thereby, the reflectance of the electroconductive laminated body surface can further be reduced.

  Moreover, in the electroconductive laminated body concerning this invention, it is preferable to use the base material whose refractive index is 1.61-1.70. Thereby, the reflectance of the electroconductive laminated body surface can further be reduced.

  In the present invention, the carbon nanotube layer and the overcoat layer laminated thereon may be collectively referred to as a conductive layer.

  In the present invention, the reflectance (luminous reflectance) of the conductive laminate surface (conductive layer surface) is preferably less than 1.7%, more preferably less than 1.5%, and further 1 Is preferably less than 4%, particularly preferably less than 1.3%. The lower limit reflectance (luminous reflectance) is not particularly limited, but is practically about 0.1%.

  By using the conductive laminate of the present invention with reduced reflectance as described above for a touch panel (for example, a resistive touch panel), the space (air layer) present in the touch panel and the surface of the conductive laminate (conductive) Interfacial reflection with the surface of the layer is reduced, and as a result, a decrease in the amount of light emitted from a display panel such as liquid crystal or organic EL (Electro-Luminescence) and transmitted through the touch panel is suppressed. That is, the amount of light transmitted through the touch panel can be relatively increased.

  Hereinafter, each component which comprises the electroconductive laminated body of this invention is demonstrated in detail.

[Base material]
Examples of the substrate used in the present invention include a resin substrate and a glass plate. As the resin base material, a resin film having a relatively small thickness (for example, a thickness of 250 μm or less) and capable of being wound in a roll shape, or a resin substrate having a relatively large thickness (for example, a thickness of more than 250 μm) can be used. . Among the above-described substrates, a resin film is preferably used from the viewpoint of productivity of the conductive laminate.

  Examples of the resin constituting the resin film and resin substrate include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyimide, polyphenylene sulfide, aramid, polypropylene, polyethylene, polylactic acid, polyvinyl chloride, polycarbonate, poly Examples include methyl methacrylate, alicyclic acrylic resin, cycloolefin resin, and triacetyl cellulose.

  As the glass of the glass plate, ordinary soda glass can be used.

  As the substrate according to the present invention, a substrate having a refractive index of 1.61-1.70 is preferably used from the viewpoint of reducing the reflectance of the surface of the conductive laminate. As such a base material, a polyethylene terephthalate film (PET film) is preferably used.

  Among polyethylene terephthalate films, biaxially stretched polyethylene terephthalate film (biaxially stretched PET film) has a relatively high refractive index and excellent properties such as tensile strength, heat resistance, solvent resistance, and transparency. Therefore, it is useful as a base material for the conductive laminate according to the present invention.

  The refractive index of the substrate is preferably 1.62 or more, more preferably 1.63 or more, and particularly preferably 1.64 or more from the viewpoint of reducing the reflectance of the surface of the conductive laminate. The upper limit of the refractive index of the substrate is preferably 1.69 or less, and more preferably 1.68 or less, from the viewpoints of the hue and interference fringes of the conductive laminate.

  The base material is preferably in the form of a film as described above, and the resin film thickness is suitably in the range of 20 to 250 μm. From the viewpoint of rigidity, strength, workability, etc., 50 μm or more is preferable, and 75 μm or more. Is more preferable. The upper limit thickness of the resin film is preferably 250 μm or less, more preferably 200 μm or less, from the viewpoint of securing a certain degree of flexibility and the workability.

  When a polyethylene terephthalate film is used as a substrate, a resin layer to be described later is provided on the surface of the polyethylene terephthalate film on which the undercoat layer is provided in order to improve the adhesion between the polyethylene terephthalate film and the undercoat layer. It is preferable.

[Undercoat layer]
The undercoat layer according to the present invention has a refractive index of 1.40 or less. The refractive index of the undercoat layer is preferably 1.38 or less, more preferably 1.37 or less, and particularly preferably 1.36 or less, from the viewpoint of reducing the reflectance of the conductive laminate surface. The lower limit of the refractive index of the undercoat layer is not particularly limited, but is practically about 1.20.

  In order to form an undercoat layer having a refractive index of 1.40 or less, the undercoat layer preferably contains silica particles. The average particle diameter of such silica particles is preferably in the range of 5 to 70 nm, more preferably in the range of 7 to 60 nm, and particularly preferably in the range of 10 to 50 nm.

  As such silica particles, colloidal silica and silica particles having a cavity inside (hollow silica) are preferably used.

  A commercial item can be used for colloidal silica. For example, “Snowtex” and “organosilica sol” of Nissan Chemical Industries, Ltd. and “CATAROID” of JGC Catalysts & Chemicals Co., Ltd. can be mentioned.

  The silica particle having a cavity inside is a silica particle having a cavity part surrounded by an outer shell. The volume occupied by the cavities in the silica particles having cavities therein, that is, the porosity of the particles is preferably 5% or more, more preferably 10% or more, and even more preferably 30% or more. The upper limit porosity is preferably 70% or less. Such silica particles having cavities are described in, for example, the method described in paragraphs [0033] to [0046] of JP-A-2001-233611 and paragraph [0043] of Japanese Patent No. 3272111. Can be manufactured by the following methods. Moreover, what is generally marketed can also be used.

  The undercoat layer preferably further contains a hydrophilic organic or inorganic binder.

  Examples of the hydrophilic organic binder include polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cell source, sodium alginate, ethylene-vinyl alcohol copolymer, polyalkylene oxide, starch, dextran, gelatin, and Those modified products can be mentioned.

  Examples of the hydrophilic inorganic binder include a hydrolyzable silane derivative, a hydrolyzate of the hydrolyzable silane derivative, and a condensate of the hydrolyzate of the hydrolyzable silane derivative.

  Examples of the hydrolyzable silane derivative include alkoxysilane. Examples of such alkoxysilanes include tetraalkoxysilane, trialkoxysilane, and dialkoxysilane.

  Hereinafter, alkoxysilanes that can be used in the present invention are exemplified.

  Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, triethoxymethoxysilane, diethoxydimethoxysilane, and trimethoxyethoxysilane.

  Examples of trialkoxysilanes include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, and pentyltrisilane. Methoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, Octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyl Methoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxy Examples thereof include silane, 3-mercaptopropyltriethoxysilane, and 3,4-epoxycyclohexylethyltrimethoxysilane.

  Examples of dialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, and diethyldiethoxysilane.

  Among the above alkoxysilanes, tetraalkoxysilane is preferable from the viewpoint that relatively good film strength can be obtained, and tetramethoxysilane (methyl silicate) and tetraethoxysilane (ethyl silicate) are preferably used.

  The above alkoxysilanes may be used alone or in combination of two or more.

  A hydrolyzate of a hydrolyzable silane derivative (alkoxysilane) is a compound produced by hydrolysis of the hydrolyzable silane derivative (alkoxysilane) described above in the presence of water.

  The condensate of a hydrolyzate of a hydrolyzable silane compound (alkoxysilane) is a compound formed by condensation after the hydrolyzable silane compound (alkoxysilane) described above is hydrolyzed in the presence of water. . As such a condensate, a condensate having a polystyrene-equivalent weight average molecular weight (Mw) of, for example, about 1,000 to 10,000 is preferably used.

  The hydrolysis reaction can be performed by a known method. For example, alkoxysilane is placed in a large amount of alcohol solvent (for example, methyl alcohol or ethyl alcohol), and reacted at a predetermined temperature for a predetermined time in the presence of water and an acid catalyst (hydrochloric acid, nitric acid, etc.). By this reaction, the alkoxysilane is hydrolyzed, followed by a condensation reaction, whereby a hydrolyzate and / or a condensate thereof is obtained.

  The above alkoxysilane, alkoxysilane hydrolyzate, and alkoxysilane hydrolyzate condensate can also be obtained from the market, for example. Examples of commercially available products include the “Colcoat” series manufactured by Colcoat.

  The undercoat layer preferably contains the above-described silica particles and a hydrophilic inorganic binder from the viewpoint of reducing the refractive index.

  From the viewpoint of further reducing the refractive index of the undercoat layer, it is preferable to form fine voids (microvoids) inside the undercoat layer. The fine voids can be present inside the silica particles and / or between the silica particles (between the silica particles and the silica particles). As for the former voids, fine voids can be present inside the silica particles by using the silica particles having the above-described voids (hollow silica) as the silica particles.

  The latter void is formed between the particles by forming an undercoat layer with a composition containing silica fine particles and a hydrophilic inorganic binder, and adjusting the content ratio of the silica fine particles and the hydrophilic inorganic binder when forming the undercoat layer. Fine voids can be present (formed) on the surface. In order to allow (form) effective fine voids between the particles, the mass ratio (A / B) of the silica particle content (A) and the hydrophilic inorganic binder content (B) is 0.4 or more. Is preferably 0.6 or more, more preferably 0.8 or more, and particularly preferably 1.0 or more. On the other hand, if the mass ratio (A / B) becomes too small, the film strength of the undercoat layer may decrease, so the upper limit mass ratio (A / B) is suitably 30 or less, and 20 or less. Is preferable, and 10 or less is particularly preferable.

  The undercoat layer is preferably hydrophilic. The coating composition (dispersion) of the carbon nanotube layer laminated on the undercoat layer is preferably water-based as described later, and from the viewpoint of improving the coating property and adhesion of the carbon nanotube layer, The coat layer is preferably hydrophilic. The hydrophilic undercoat layer can preferentially adsorb the dispersant (insulating substance) contained in the carbon nanotube layer to improve the conductivity of the carbon nanotube layer.

  As described above, the hydrophilic undercoat layer can be formed by applying a coating composition containing silica particles and a hydrophilic inorganic or organic binder.

  As described above, the thickness of the undercoat layer is preferably adjusted so that the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat layer is in the range of 75 to 125 nm.

  The thickness of the undercoat layer is specifically determined from the viewpoint of reducing the reflectivity of the surface of the conductive laminate, and from the viewpoint of improving the coating properties of the carbon nanotube layer and developing the adsorption function of the dispersant contained in the carbon nanotube layer. Is preferably in the range of 15 to 65 nm, more preferably in the range of 20 to 60 nm, further preferably in the range of 25 to 55 nm, and particularly preferably in the range of 30 to 50 nm.

  The undercoat layer can be applied by a wet coating method. Examples of the wet coating method include cast coating, dip coating, spin coating, knife coating, kiss coating, roll coating, gravure coating, slot die coating, and bar coating.

[Carbon nanotube layer]
The carbon nanotube layer according to the present invention is a layer containing at least carbon nanotubes.

  The carbon nanotube is not particularly limited as long as it has a shape obtained by winding one surface of graphite into a cylindrical shape. Single-walled carbon nanotubes in which one surface of graphite is wound in one layer, wound in multiple layers. Multi-walled carbon nanotubes can be applied. Among these, double-walled carbon nanotubes in which one surface of graphite is wound in two layers are preferable because of high conductivity and dispersibility of the carbon nanotubes in the dispersion.

  A carbon nanotube having a diameter of about 0.3 to 20 nm and a length of about 0.1 to 20 μm is preferably used. In particular, from the viewpoint of increasing the transparency of the conductive layer and reducing the surface resistance, the carbon nanotubes preferably have a diameter of 1 to 10 nm and a length of 1 to 10 μm.

  For example, the carbon nanotube is manufactured as follows. A powdery catalyst in which iron is supported on magnesia is present in the entire horizontal cross-sectional direction of the reactor in a vertical reactor, and methane is supplied in the vertical direction into the reactor. The carbon nanotubes containing single- to five-layer carbon nanotubes can be obtained by contacting the carbon nanotubes at 200 ° C. to produce carbon nanotubes and then oxidizing the carbon nanotubes.

  Carbon nanotubes can be manufactured and then subjected to an oxidation treatment to increase the ratio of single to 5 layers (particularly, the ratio of 2 to 5 layers). The oxidation treatment is performed, for example, by a nitric acid treatment method. Nitric acid is preferable because it also acts as a dopant for the carbon nanotubes. The dopant is a function of giving a surplus electron to the carbon nanotube or taking away the electron to form a hole, thereby generating a freely movable carrier, thereby improving the conductivity of the carbon nanotube. Is. The conditions for the nitric acid treatment are not particularly limited, but are usually performed in an oil bath at 140 ° C. Although the nitric acid treatment time is not particularly limited, it is preferably in the range of 5 to 50 hours.

  The carbon nanotube layer can be formed by applying a coating composition containing a carbon nanotube dispersion liquid by a wet coating method. Examples of the wet coating method include cast coating, dip coating, spin coating, knife coating, kiss coating, roll coating, gravure coating, slot die coating, and bar coating. Of these, the slot die coating method is preferably used.

  The carbon nanotube dispersion preferably contains a carbon nanotube dispersant. As such a dispersant, an ionic dispersant having high dispersibility is preferably used. Examples of the ionic dispersant include an anionic dispersant, a cationic dispersant, and an amphoteric dispersant. Among these ionic dispersants, anionic dispersants are preferably used because of excellent dispersibility and dispersion retention of carbon nanotubes. Among the anionic dispersants, carboxymethyl cellulose and salts thereof (sodium salt, ammonium salt, etc.) and polystyrene sulfonic acid salt are preferable because carbon nanotubes can be efficiently dispersed.

  The content of the dispersant is preferably in the range of 50 to 1,000 parts by mass with respect to 100 parts by mass of the carbon nanotubes from the viewpoint of ensuring good dispersibility without reducing the conductivity of the carbon nanotubes. The range of -600 mass parts is more preferable, and the range of 200-400 mass parts is particularly preferable.

  The dispersion medium used for the preparation of the carbon nanotube dispersion liquid is preferably water from the viewpoints that the above-described dispersant can be safely dissolved and that the waste liquid can be easily treated.

  The carbon nanotube dispersion is, for example, a carbon nanotube and a dispersing agent mixed in a dispersion medium (for example, a ball mill, a bead mill, a sand mill, a roll mill, a homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, an ultrasonic device, an attritor, a resolver, It can be prepared by dispersing using a paint shaker or the like. These mixing and dispersing machines may be used alone or may be dispersed stepwise by combining a plurality of mixing and dispersing machines. Among them, a method of preliminarily dispersing with a vibrating ball mill and then dispersing using an ultrasonic device is preferable because the dispersibility of the carbon nanotubes is good.

  The concentration of the carbon nanotubes when dispersing the carbon nanotubes is preferably in the range of 0.003 to 0.15% by mass because the treatment time at the time of dispersion can be shortened. The carbon nanotube dispersion prepared in this manner is further diluted and adjusted to a predetermined concentration suitable for coating.

  In applying the carbon nanotube dispersion liquid, alcohol or a surfactant can be contained in the carbon nanotube dispersion liquid in order to improve the coating property. Among these, alcohol is preferable, and lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and isopropyl alcohol are preferably used.

The content of carbon nanotubes in the carbon nanotube layer is appropriately set depending on the use of the conductive laminate, but in the case of touch panel use, a range of 0.5 to 20 mg / m ² is appropriate, and 1 to 15 mg / m 2. The range of ² is preferable, and the range of 1 to 10 mg / m ² is particularly preferable. Thereby, the surface resistance value can be set to 1 × 10 ⁴ Ω / □ or less while maintaining the high transmittance of the conductive laminate.

Also, the total solid content coating amount of the carbon nanotube layer is suitably in the range of 2 to 50 mg / ^{m 2,} preferably in the range of 3 to 30 mg / ^{m 2,} the range of 4~25mg / ^{m 2} is preferred.

  The thickness of the carbon nanotube layer obtained as described above is usually in the range of 1 to 20 nm, but in the present invention, the range of 2 to 15 nm is more preferable, and the range of 3 to 10 nm is particularly preferable.

[Overcoat layer]
The overcoat layer is formed by coating on the carbon nanotube layer. The overcoat layer serves to protect the carbon nanotube layer.

  The overcoat layer has a refractive index of 1.43 or less. The refractive index of the overcoat layer is preferably 1.42 or less, more preferably 1.40 or less, further preferably 1.38 or less, particularly from the viewpoint of reducing the reflectance of the surface of the conductive laminate. 37 or less is preferable. The lower limit of the refractive index of the overcoat layer is not particularly limited, but is practically about 1.25.

  The overcoat layer is preferably formed of a material having a relatively low refractive index in order to make its refractive index 1.43 or less. Examples of the material having a relatively low refractive index include silicon compounds and fluorine compounds, and these compounds can be used alone or in combination of two or more.

  Examples of the silicon compound include alkoxysilane, alkoxysilane hydrolyzate, alkoxysilane hydrolyzate condensate, alkoxysilane having a polymerizable functional group, polysiloxane compound, silica particles, and the like. Can be used alone or in combination of two or more.

  As alkoxysilane, the same compound as the alkoxysilane used for an undercoat layer can be used.

  Examples of the alkoxysilane having a polymerizable functional group include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane.

  As the polysiloxane compound, a compound having a weight average molecular weight of 5,000 or less is preferable, and a compound having a polymerizable functional group (ethylenically unsaturated group such as vinyl group or acrylic group) in the molecule is preferable. For example, a polysiloxane compound having an acrylic group at one or both ends of the molecule can be mentioned.

  As the silica particles, particles having an average particle diameter of 5 to 100 nm are preferable, particles having an average particle diameter of 7 to 70 nm are preferable, and particles having an average particle diameter of 10 to 60 nm are particularly preferable. As the silica particles, colloidal silica and silica particles having a cavity inside (hollow silica) are preferably used.

  Examples of the fluorine compound include fluorine-containing monomers, fluorine-containing oligomers, fluorine-containing polymer compounds, fluorine-containing silane compounds, and magnesium fluoride particles. These compounds can be used alone or in combination of two or more. Here, the fluorine-containing monomer and fluorine-containing oligomer are monomers and oligomers having an ethylenically unsaturated group such as a vinyl group or an acrylic group and a fluorine atom in the molecule.

  Examples of the fluorine-containing monomer and fluorine-containing oligomer include 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, and 2- (perfluorobutyl). ) Ethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2- (perfluorooctyl) ethyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, β- (per Fluoro-containing (meth) acrylic esters such as fluorooctyl) ethyl (meth) acrylate, di- (α-fluoroacrylic acid) -2,2,2-trifluoroethylethylene glycol, di- (α-fluoroacrylic acid) ) -2,2,3,3,3-pentafluoropropylethylene glycol, di (Α-fluoroacrylic acid) -2,2,3,3,4,4,4-hexafluorobutylethylene glycol, di- (α-fluoroacrylic acid) -2,2,3,3,4,4,4 5,5,5-nonafluoropentylethylene glycol, di- (α-fluoroacrylic acid) -2,2,3,3,4,4,5,5,6,6,6-undecafluorohexylethylene glycol , Di- (α-fluoroacrylic acid) -2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoroheptylethylene glycol, di- (α-fluoro Acrylic acid) -2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctylethylene glycol, di- (α-fluoroacrylic acid) -3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8-tridecafluorooctylethylene glycol, di- (α-fluoroacrylic acid) -2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9 , 9-heptadecafluorononylethylene glycol and the like di- (α-fluoroacrylic acid) fluoroalkyl esters.

  Examples of the fluorine-containing polymer compound include a fluorine-containing copolymer having a fluorine-containing monomer and a monomer for imparting a crosslinkable group as constituent units. Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc. ), (Meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) and M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, and the like. As a monomer for imparting a crosslinkable group, in addition to a (meth) acrylate monomer having a crosslinkable functional group in the molecule like glycidyl methacrylate, it has a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc. ) Acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.).

  Examples of the fluorine-containing silane compound include trifluoromethylmethoxysilane, trifluoromethylethoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane. Heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecylmethyldimethoxysilane, and the like.

  As the magnesium fluoride particles, particles having an average particle diameter of 5 to 100 nm are preferable, particles having an average particle diameter of 7 to 70 nm are preferable, and particles having an average particle diameter of 10 to 60 nm are particularly preferable.

  The overcoat layer can contain an ultraviolet curable acrylic monomer or oligomer in addition to the above silicon compound and / or fluorine compound.

  The ultraviolet curable acrylic monomer is not particularly limited, and examples thereof include methyl (meth) acrylate, lauryl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and phenoxyethyl (meth) acrylate. Monofunctional acrylates such as tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxy (meth) acrylate, Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythrito Rutri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Multifunctional acrylates such as tripentaerythritol tri (meth) acrylate, tripentaerythritol hexa (meth) triacrylate, trimethylolpropane (meth) acrylic acid benzoate, trimethylolpropane benzoate, glycerin di (meth) acrylate hexa Urethane acrylates such as methylene diisocyanate, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate, etc. It can be mentioned.

  Examples of the ultraviolet curable oligomer include urethane acrylate oligomer.

  From the viewpoint of forming an overcoat layer having a relatively low refractive index, the overcoat layer is preferably formed from the following thermosetting composition.

  Examples of such a thermosetting composition include a composition mainly composed of a siloxane polymer formed by bonding with silica particles. Specifically, such a composition is obtained by reacting and homogenizing the silica component of the silica particles and the siloxane polymer of the matrix, and the siloxane polymer bonded to the silica particles is present in the presence of the silica particles. A polyfunctional silane compound can be obtained by forming a silanol compound once by a known hydrolysis reaction in a solvent with an acid catalyst and utilizing a known condensation reaction.

  As the above silica particles, colloidal silica and silica particles having a cavity inside (hollow silica) are preferable, and the average particle diameter is preferably in the range of 5 to 100 nm, more preferably in the range of 7 to 70 nm, and particularly in the range of 10 to 60 nm. The range of is preferable.

  As said polyfunctional silane compound, the above-mentioned alkoxysilane compound and fluorine-containing silane compound are mentioned.

  The thermosetting composition preferably further contains a curing agent. Examples of the curing agent include titanium, zirconium, aluminum, and magnesium. Among these, from the viewpoint of relatively reducing the refractive index, an aluminum-based or magnesium-based curing agent having a low refractive index is preferable. These curing agents can be easily obtained by reacting a metal alkoxide with a chelating agent. Examples of chelating agents include β-diketones such as acetylacetone, benzoylacetone, and dibenzoylmethane; β-keto acid esters such as ethyl acetoacetate and ethyl benzoylacetate.

  Preferable specific examples of the metal chelate compound include ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetyl acetate bis (ethyl acetoacetate), aluminum tris (acetyl) Examples include aluminum chelate compounds such as acetonate), and magnesium chelate compounds such as ethyl acetoacetate magnesium monoisopropylate, magnesium bis (ethyl acetoacetate), alkyl acetoacetate magnesium monosopropylate, and magnesium bis (acetylacetonate). Of these, aluminum tris (acetylacetonate), aluminum tris (ethyl acetoacetate), magnesium bis (acetylacetonate), and magnesium bis (ethyl acetoacetate) are preferable, considering storage stability and availability. Then, aluminum tris (acetylacetonate) and aluminum tris (ethylacetoacetate) are particularly preferable.

  The overcoat layer is preferably formed by applying a coating composition (coating solution) having the above-described composition by a wet coating method, and drying and curing (thermal curing or curing by ultraviolet irradiation). As the wet coating method, a coating method similar to the wet coating method used for coating the carbon nanotube layer described above can be used.

  As described above, the thickness of the overcoat layer is preferably adjusted so that the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat is in the range of 75 to 125 nm.

  The thickness of the overcoat layer is specifically preferably in the range of 20 to 100 nm, and in the range of 30 to 90 nm, from the viewpoint of reducing the reflectance of the surface of the conductive laminate and protecting the carbon nanotubes. More preferably, the range of 40 to 80 nm is particularly preferable.

[Resin layer]
When using a polyethylene terephthalate film (especially a biaxially stretched polyethylene terephthalate film) as the base material, a resin layer is interposed between the polyethylene terephthalate film and the undercoat layer in order to improve the adhesion to the undercoat layer. Is preferred. That is, it is preferable to use a polyethylene terephthalate film in which a resin layer is previously laminated as a base material.

  The resin layer preferably contains at least one resin selected from the group consisting of a polyester resin, an acrylic resin, and a urethane resin as a resin.

  The resin content in the resin layer is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more with respect to 100% by mass of the total solid content of the resin layer. The upper limit content is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less.

  The resin layer preferably further contains a crosslinking agent. The resin layer is preferably a thermosetting layer containing a resin and a crosslinking agent. By using such a thermosetting layer as the resin layer, the adhesion between the base material (polyethylene terephthalate film) and the undercoat layer can be further improved. The conditions (heating temperature, time) for thermosetting the resin layer are not particularly limited, but the heating temperature is preferably 70 ° C or higher, more preferably 100 ° C or higher, particularly preferably 150 ° C or higher, and most preferably 200 ° C or higher. . The upper limit is preferably 300 ° C. or lower. The heating time is preferably in the range of 5 to 300 seconds, and more preferably in the range of 10 to 200 seconds.

  Examples of the crosslinking agent contained in the resin layer include a melamine crosslinking agent, an oxazoline crosslinking agent, a carbodiimide crosslinking agent, an isocyanate crosslinking agent, an aziridine crosslinking agent, and an epoxy crosslinking agent. Among these, melamine-based crosslinking agents, oxazoline-based crosslinking agents, and carbodiimide-based crosslinking agents are preferably used.

  The content of the crosslinking agent in the resin layer is preferably in the range of 1 to 40% by mass, more preferably in the range of 3 to 30% by mass, with respect to 100% by mass of the total solid content of the resin layer. A range is particularly preferred.

  The resin layer preferably contains organic or inorganic particles for further improving slipperiness and blocking resistance. Examples of such particles include, but are not limited to, inorganic particles such as silica, calcium carbonate, zeolite particles, acrylic particles, silicone particles, polyimide particles, Teflon (registered trademark) particles, crosslinked polyester particles, crosslinked polystyrene particles, Organic particles such as crosslinked polymer particles and core-shell particles may be mentioned. Among these particles, silica is preferable, and colloidal silica is more preferably used.

  The average particle diameter of the particles is preferably 30 nm or more, more preferably 50 nm or more, and particularly preferably 100 nm or more from the viewpoint of improving slipperiness and blocking resistance. The upper limit of the average particle diameter is preferably 500 nm or less, more preferably 400 nm or less, and particularly preferably 300 nm or less.

  The content of the particles in the resin layer is preferably in the range of 0.05 to 8% by mass and more preferably in the range of 0.1 to 5% by mass with respect to 100% by mass of the total solid content of the resin layer.

  The resin layer is preferably laminated on a base material (polyethylene terephthalate film) by a wet coating method. In particular, the resin layer is preferably laminated by a so-called “in-line coating method” in which the resin layer is laminated in the production process of the substrate. When applying a resin layer on a base material, it is preferable to perform corona discharge treatment, flame treatment, plasma treatment, etc. on the surface of the base material as a preliminary treatment for improving applicability and adhesion.

  Examples of the wet coating method include a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a slot die coating method, a spin coating method, an extrusion coating method, and a dip coating method. be able to.

  The in-line coating method will be described with reference to a production example of a polyethylene terephthalate film having a resin layer, but the present invention is not limited to this.

  After vacuum drying PET pellets with an intrinsic viscosity of 0.5 to 0.8 dl / g, which is a raw material for polyethylene terephthalate (PET) film, it is supplied to an extruder and melted at 260 to 300 ° C., and then in sheet form from a T-shaped die. And is wound around a mirror-casting drum having a surface temperature of 10 to 60 ° C. using an electrostatic application casting method, and is cooled and solidified to produce an unstretched PET film. This unstretched PET film is stretched 2.5 to 5 times in the longitudinal direction (referring to the traveling direction of the film and also referred to as “longitudinal direction”) between rolls heated to 70 to 100 ° C. At least one surface of the uniaxially stretched PET film obtained by this stretching is subjected to corona discharge treatment in the air, the wetting tension of the surface is set to 47 mN / m or more, and the coating composition for forming a resin layer is applied to the treated surface as described above. Apply by.

  Next, the uniaxially stretched PET film coated with the coating composition is held with a clip and guided to a drying zone, dried at a temperature lower than Tg of the uniaxially stretched PET film, then raised to a temperature equal to or higher than Tg, and again near Tg. Drying at a temperature, followed by continuous stretching in a heating zone at 70 to 150 ° C. in the transverse direction (referring to a direction perpendicular to the film traveling direction, also referred to as “width direction”) 2.5 to 5 times, followed by 180 A laminated polyethylene terephthalate film in which a resin layer is laminated on a PET film (biaxially stretched PET film) in which crystal orientation is completed is obtained by performing heat treatment in a heating zone of ˜240 ° C. for 5 to 40 seconds. In addition, you may perform a 3-12% relaxation process as needed during the said heat processing. Biaxial stretching may be longitudinal, transverse sequential stretching, or simultaneous biaxial stretching, and may be re-stretched in either the longitudinal or transverse direction after longitudinal and transverse stretching.

  The refractive index of the resin layer is preferably in the range of 1.55 to 1.70, from the viewpoint of reducing the reflectance of the surface of the conductive laminate and bringing the color tone of the conductive layer closer to neutral. A range of .69 is more preferred.

  In particular, from the viewpoint of further reducing the reflectance of the conductive laminate surface, the refractive index of the resin layer is preferably in the range of 1.61-1.70, more preferably in the range of 1.62-1.69, A range of 1.63-1.67 is particularly preferred.

  The refractive index (1.55 to 1.70) of the resin layer described above is relatively lower than the refractive index (1.48 to 1.54) of the resin layer generally laminated on a conventional polyethylene terephthalate film. Such a resin layer having a high refractive index and a relatively high refractive index can be obtained, for example, by containing a high refractive index material such as a high refractive index resin or metal oxide particles.

  Examples of the high refractive index resin include a resin having a high refractive index by introducing an aromatic ring, a sulfur atom, a bromine atom, or the like into a resin such as a polyester resin, an acrylic resin, or a urethane resin.

  Among the high refractive index resins, a polyester resin having a condensed aromatic ring in the molecule is preferably used. The condensed aromatic ring is preferably a naphthalene ring or a fluorene ring.

  The polyester resin is generally obtained by polycondensation from a carboxylic acid component and a glycol component. The polyester resin having a naphthalene ring in the molecule can be synthesized by using a dicarboxylic acid having a naphthalene ring such as 1,4-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid as a carboxylic acid component. . The refractive index of the polyester resin having a naphthalene ring in the molecule can be controlled by adjusting the ratio of the dicarboxylic acid having a naphthalene ring in the total carboxylic acid component.

  The polyester resin having a fluorene ring in the molecule can be synthesized by using a compound having a fluorene ring as the carboxylic acid component and / or glycol component. The refractive index of the polyester resin can be controlled by adjusting the content of the compound having a fluorene ring. The polyester resin which has a fluorene ring in a molecule | numerator is described in detail in the international publication 2009/145075, for example, It can synthesize | combine with reference to it.

  The high refractive index resin can be used by replacing part or all of the entire resin constituting the resin layer.

  Examples of the metal oxide particles include titanium oxide, zirconium oxide, zinc oxide, tin oxide, antimony oxide, cerium oxide, iron oxide, zinc antimonate, tin oxide-doped indium oxide (ITO), and antimony-doped tin oxide (ATO). , Phosphorus-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, fluorine-doped tin oxide, and the like. These metal oxide particles may be used alone or in combination. Among the metal oxide particles, titanium oxide and zirconium oxide are particularly preferable because the refractive index of the resin layer can be increased without reducing transparency.

  The content of the metal oxide particles in the resin layer is appropriately adjusted according to the refractive index of the resin layer, but is adjusted in the range of 10 to 80% by mass with respect to 100% by mass of the total solid content of the resin layer. Is preferable, and it is more preferable to adjust in 20-70 mass%.

  When the resin layer contains metal oxide particles as a high refractive index material, the resin layer preferably contains at least one resin selected from the group consisting of a polyester resin, an acrylic resin, and a urethane resin. Moreover, it is preferable to use a part or all of these resins in place of the above-described high refractive index polyester resin, whereby the content of metal oxide particles can be reduced.

  The thickness of the resin layer is not particularly limited, but from the viewpoints of coating properties and thickness accuracy in the resin layer laminating process, slipperiness and blocking resistance of the resin layer, or appearance (color unevenness, etc.) of the conductive laminate. The thickness of is preferably less than 200 nm, more preferably less than 120 nm, and particularly preferably less than 50 nm.

  The lower limit thickness of the resin layer is preferably 5 nm or more, and more preferably 10 nm or more from the viewpoint of improving the adhesion between the substrate and the undercoat layer.

[Conductive laminate]
In the present invention, the undercoat layer and the conductive layer (the conductive layer composed of the carbon nanotube layer and the overcoat layer) may be provided only on one side of the base material, or may be provided on both sides of the base material. Good.

  Moreover, when an undercoat layer and a conductive layer are provided only on one side of the substrate, a hard coat layer described later can be provided on the opposite side of the substrate.

  The conductive laminate of the present invention is suitable for a transparent conductive film (electrode substrate) of a touch panel. In order to use suitably for a touch panel, the surface resistance value of the surface of the conductive layer of the conductive laminate is preferably low from the viewpoint of driving stability. Specifically, the surface resistance value on the surface of the conductive layer of the conductive laminate is preferably 10,000Ω / □ or less, more preferably 5,000Ω / □ or less, and particularly preferably 2,000Ω / □ or less. The lower limit is about 1Ω / □.

[Hard coat layer]
In the conductive laminate of the present invention, a hard coat layer can be provided on the surface opposite to the undercoat layer and the conductive layer with the base material interposed therebetween. The hard coat layer is provided for imparting scratch resistance, antifouling property or fingerprint resistance. Further, it is possible to impart antiglare properties by forming fine irregularities on the surface. As the hard coat layer, a thermosetting acrylic resin or an ultraviolet curable acrylic resin is preferably used from the viewpoint of excellent properties such as transparency and hardness when cured.

  The thickness of the hard coat layer is preferably in the range of 0.5 to 7 μm and more preferably in the range of 1 to 5 μm from the viewpoint of imparting good curling properties and scratch resistance to the conductive laminate.

  When laminating a hard coat layer on a substrate, it is preferable to interpose a resin layer between the substrate and the hard coat layer in order to improve adhesion between the substrate and the hard coat layer. Hereinafter, the resin layer provided between the base material and the hard coat layer is referred to as a resin layer B. In particular, when a polyethylene terephthalate film (especially a biaxially stretched polyethylene terephthalate film) is used as the substrate, it is preferable to interpose the resin layer B between the polyethylene terephthalate film and the hard coat layer.

  When a polyethylene terephthalate film having a refractive index of 1.61 to 1.70 is used as the substrate, the refractive index of the resin layer B is preferably 1.55 to 1.60.

  The refractive index of the hard coat layer is usually in the range of 1.48 to 1.54, and the refractive index difference between the above-described polyethylene terephthalate film (1.61 to 1.70) and the hard coat layer is large. As a result, interference fringes may occur on the surface side of the hard coat layer.

  Generation | occurrence | production of this interference fringe can be suppressed by making the refractive index of the resin layer B into 1.55-1.60. Furthermore, from the viewpoint of suppressing the generation of interference fringes, the refractive index of the resin layer B is more preferably in the range of 1.56 to 1.59, and particularly preferably in the range of 1.57 to 1.59.

  The thickness of the resin layer B is preferably in the range of 60 to 130 nm, particularly preferably in the range of 70 to 120 nm, from the viewpoint of suppressing the generation of interference fringes.

  Such a resin layer B (a resin layer having a refractive index of 1.55 to 1.60) can have the same configuration as the resin layer provided on the above-described undercoat layer side. By adjusting the content of the high refractive index resin or metal oxide particles contained in the resin layer provided on the undercoat layer side, the refractive index of the resin layer B is set in the range of 1.55 to 1.60. be able to.

[Method for producing conductive laminate]
The conductive laminate according to the present invention is preferably manufactured, for example, by the following manufacturing method. That means
When producing a conductive laminate in which an undercoat layer, a carbon nanotube layer, and an overcoat layer are laminated in order from the substrate side on at least one surface of the substrate, the refractive index is 1.40 or less on the substrate. A step of applying an undercoat layer-forming coating composition and laminating an undercoat layer, a step of applying a carbon nanotube layer-forming coating composition on the undercoat layer and laminating a carbon nanotube layer, the carbon It is a manufacturing method of a conductive laminated body including the process of apply | coating the coating composition for overcoat layer formation which has a refractive index of 1.43 or less on a nanotube layer, and laminating | stacking an overcoat layer.

[Application of conductive laminate to touch panel]
The conductive laminate of the present invention is preferably applied to a touch panel (particularly a resistive film type touch panel). Hereinafter, the example of an aspect when the electroconductive laminated body of this invention is applied to a resistive film type touch panel is demonstrated.

  FIG. 1 is a schematic cross-sectional view showing an example of a resistive film type touch panel using the conductive laminate of the present invention. The resistive touch panel is usually fixed with a spacer 3 so that the conductive laminate 1 constituting the upper electrode and the conductive laminate 2 constituting the lower electrode face each other with the conductive layer 10 and the conductive layer 22 facing each other. The space 5 is arranged. The resistive touch panel is touch-operated with the touch pen 4 or a finger.

  The conductive laminate of the present invention can be used for both the conductive laminate 1 constituting the upper electrode and the conductive laminate 2 constituting the lower electrode, but at least the conductive laminate 1 constituting the upper electrode. It is preferable to use for. FIG. 1 shows an embodiment in which the conductive laminate of the present invention is used for the conductive laminate 1 constituting the upper electrode.

  The conductive laminate 1 (the conductive laminate of the present invention) has an undercoat layer 12, a carbon nanotube layer 13 and an overcoat layer 14 on one surface (lower surface) of a substrate 11, and the other surface. A hard coat layer 15 is provided. The conductive layer 10 includes a carbon nanotube layer 13 and an overcoat layer 14.

  The conductive laminate 2 constituting the lower electrode is not particularly limited, but here, a conductive laminate in which the conductive layer 22 is laminated on the substrate 21 is exemplified.

  The resistive film type touch panel is incorporated on an image display panel of an image display device (such as a portable device or a tablet terminal). An image ("light" in the figure) emitted from an image display panel (liquid crystal or organic EL) (not shown) is displayed on the viewer side via the touch panel (through the touch panel). Here, if the surface reflectance of the conductive layer 10 of the conductive laminate 1 is high, the presence of the space (air layer) 5 increases the interface reflection between the surface of the conductive layer 10 and the air layer 5, thereby There is a case in which light emitted from an image display panel such as a liquid crystal is diffusely reflected when passing through the touch panel, and the amount of light passing through the touch panel is reduced.

  The said subject is suppressed by using the electroconductive laminated body of this invention as the electroconductive laminated body 1. FIG.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples. The measurement method, evaluation method, and materials used in this example are shown below.

[Measurement method and evaluation method]
(1) Measuring method of refractive index About the coating film formed by apply | coating each coating composition for forming each layer (resin layer, undercoat layer, overcoat layer, hard-coat layer) on a silicon wafer, Using a high-speed spectrometer M-2000 (manufactured by JA Woollam), the change in the polarization state of the reflected light of the coating film was measured at an incident angle of 60 degrees, 65 degrees, and 70 degrees, and the analysis software WVASE used a wavelength of 550 nm. The refractive index of was calculated.

  Moreover, the refractive index of the base material measured the refractive index of 550 nm with the Abbe refractometer according to JISK7105 (1981).

(2) Measuring method of thickness of resin layer A cross section of a base material (polyethylene terephthalate film) on which a resin layer is laminated is cut into ultrathin sections and stained by RuO ₄ staining, OsO ₄ staining, or double staining of both. The section method is observed under the following conditions where the cross-sectional structure is visible with a TEM (transmission electron microscope), and the thickness of the resin layer is measured from the cross-sectional photograph. The thickness was measured at three locations, and the average value was taken as the thickness.
Measurement device: Transmission electron microscope (H-7100FA type, manufactured by Hitachi, Ltd.)
・ Measurement conditions: Acceleration voltage 100kV
-Sample preparation: frozen ultrathin section method-Magnification: 300,000 times.

(3) Measuring method of thickness of each layer constituting conductive laminate The thickness of the hard coat layer, the undercoat layer, the carbon nanotube layer and the overcoat layer is obtained by cutting a cross section of the conductive laminate into ultrathin sections, Observation is performed with a transmission electron microscope) at an acceleration voltage of 100 kV (observation at a magnification of 1 to 300,000 times), and the thickness is measured from the cross-sectional photograph. The thickness was measured at three locations, and the average value was taken as the thickness.

(4) Measuring method of average particle diameter of particles A cross section of a sample (conductive laminate) in which layers containing particles are laminated is observed with a TEM (transmission electron microscope) at an acceleration voltage of 100 kV (1 to 300,000 times) The maximum length of each of 30 randomly selected particles was measured from the cross-sectional photograph, and the value obtained by arithmetically averaging them was taken as the average particle diameter of the particles.

(5) Measuring method of luminous reflectance <Sample preparation>
The conductive laminate was cut out to 150 mm × 150 mm, the surface opposite to the side provided with the conductive layer was roughened with sandpaper, and further painted with black ink to prepare a measurement sample.

<Measurement>
Using a spectrophotometer (“UV3150PC” manufactured by Shimadzu Corporation), the reflectance (single-sided reflection) at a wavelength of 380 to 780 nm was measured at an incident angle of 5 degrees from the measurement surface (surface of the conductive layer) of the measurement sample. The luminous reflectance of the C light source (reflection stimulation value Y defined in JIS Z8701-1999) was determined. The spectral solid angle was measured with a spectrophotometer, and the reflectance (single-sided light reflection) was calculated according to JIS Z8701-1999. The calculation formula is as follows.
T = K ∫S (λ) · y (λ) · R (λ) · dλ (however, the integration interval is 380 to 780 nm)
T: single-sided light reflectance S (λ): standard light distribution used for color display y (λ): color matching function R (λ) in XYZ display system: spectral solid angle reflectance.

(6) Measuring method of total line transmittance The total light transmittance of the touch panel was measured using a turbidimeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) based on JIS-K7361 (1997).

[Materials used]
[Coating composition for forming resin layer]
(Coating composition a1)
100 parts by mass of the following naphthalene ring-containing polyester resin, 15 parts by mass of a melamine-based crosslinking agent (methylol-type melamine-based crosslinking agent (“Nicarac MW12LF” manufactured by Sanwa Chemical Co., Ltd.)), and an average particle diameter of 190 nm It is an aqueous dispersion containing 1 part by mass of colloidal silica. The refractive index of this coating composition (refractive index measured by the above (1) “refractive index measurement method”) was 1.58. In addition, the refractive index of the coating composition shown below was calculated | required with the measuring method similar to the above.

<Naphthalene ring-containing polyester resin>
A polyester resin having the following copolymer composition.
・ Carboxylic acid component terephthalic acid 35mol%
2,6-Naphthalenedicarboxylic acid 9 mol%
5-Na sulfoisophthalic acid 6 mol%
・ Glycol component ethylene glycol 49 mol%
Diethylene glycol 1 mol%.

(Coating composition a2)
100 parts by mass of the naphthalene ring-containing polyester resin, 60 parts by mass of zirconium oxide, and 15 parts by mass of a melamine-based cross-linking agent (methylol-type melamine-based cross-linking agent (“Nicarac MW12LF” manufactured by Sanwa Chemical Co., Ltd.)) An aqueous dispersion containing 1 part by mass of colloidal silica having an average particle diameter of 190 nm. The refractive index of this coating composition was 1.65.

(Coating composition a3)
100 parts by mass of the following fluorene ring-containing polyester resin, 15 parts by mass of a melamine-based crosslinking agent (methylol-type melamine-based crosslinking agent (“Nicarac MW12LF” manufactured by Sanwa Chemical Co., Ltd.)), and an average particle diameter of 190 nm It is an aqueous dispersion containing 1 part by mass of colloidal silica. The refractive index of this coating composition was 1.63.

<Polyester resin containing fluorene ring>
A polyester resin having the following copolymer composition.
・ Carboxylic acid component Succinic acid 40mol%
5-Na sulfoisophthalic acid 10 mol%
-Glycol component 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene 42 mol%
Ethylene glycol 8 mol%.

(Coating composition a4)
100 parts by mass of the following acrylic resin, 15 parts by mass of melamine-based cross-linking agent (methylol-type melamine-based cross-linking agent (“Nicarac MW12LF” manufactured by Sanwa Chemical Co., Ltd.)), and 1 colloidal silica having an average particle diameter of 190 nm An aqueous dispersion containing parts by mass. The refractive index of this coating composition was 1.52.

<Acrylic resin>
An acrylic resin having the following copolymer composition.
・ Methyl methacrylate 63% by weight
Ethyl acrylate 35% by weight
Acrylic acid 1% by weight
N-methylolacrylamide 1% by weight.

[Coating composition for forming undercoat layer]
(Coating composition uc1)
Colloidal silica having an average particle size of 22 nm ("Snowtex" (registered trademark), ST-O-40, manufactured by Nissan Chemical Industries, Ltd.) and an oligomer of tetramethoxysilane ("Colcoat" (registered trademark), manufactured by Colcoat Co., Ltd.) ) Methyl silicate 51) was mixed at a solid content mass ratio of 70:30 and adjusted to a solid content concentration of 1% by mass with isopropyl alcohol to obtain a coating composition. The refractive index of this coating composition was 1.33.

(Coating composition uc2)
Silica particles having an average particle diameter of 40 nm having voids inside (manufactured by JGC Catalysts & Chemicals Co., Ltd., isopropyl alcohol dispersion sol), and hydrophilic polysilicate (“Colcoat” (registered trademark) N103X of Colcoat Co., Ltd.) The mixture was mixed at a solid content mass ratio of 55:45, and adjusted to a solid content concentration of 1% by mass with isopropyl alcohol to obtain a coating composition. The refractive index of this coating composition was 1.35.

(Coating composition uc3)
Silica particles having an average particle diameter of 40 nm and having cavities (manufactured by JGC Catalysts & Chemicals Co., Ltd., isopropyl alcohol dispersion sol) 20 parts by mass in terms of solid content, tetramethoxysilane oligomer (Colcoat Co., Ltd.) (Registered trademark) methyl silicate 51) is mixed with 20 parts by mass in terms of solid content and 34 parts by mass of ammonia water (ammonia 28 mass%), and further adjusted with isopropyl alcohol so that the solid content concentration becomes 1 mass%. A coating composition was obtained. The refractive index of this coating composition was 1.36.

(Coating composition uc4)
Colloidal silica having an average particle size of 22 nm ("Snowtex" (registered trademark), ST-O-40, manufactured by Nissan Chemical Industries, Ltd.) and hydrophilic polysilicate ("Colcoat" (registered trademark), manufactured by Colcoat Co., Ltd.) N-103X) was mixed at a solid content mass ratio of 50:50 and adjusted to a solid content concentration of 1% by mass with isopropyl alcohol to obtain a coating composition. The refractive index of this coating composition was 1.38.

(Coating composition uc5)
Colloidal silica having an average particle size of 12 nm (“Snowtex” (registered trademark), ST-O from Nissan Chemical Industries, Ltd.) and hydrophilic polysilicate (“Colcoat” (registered trademark) N— from Colcoat, Inc.) 103X) at a solid content mass ratio of 55:45, and adjusted to a solid content concentration of 1% by mass with isopropyl alcohol to obtain a coating composition. The refractive index of this coating composition was 1.39.

(Coating composition uc6)
Hydrophilic polysilicate ("Colcoat" (registered trademark) N-103X of Colcoat Co., Ltd.) was adjusted with isopropyl alcohol so that the solid concentration was 1% by mass to obtain a coating composition. The refractive index of this coating composition was 1.44.

[Coating composition for forming overcoat layer]
(Coating composition oc1)
95.2 parts by mass of methyltrimethoxysilane and 65.4 parts by mass of trifluoropropyltrimethoxysilane were dissolved in 300 parts by mass of propylene glycol monomethyl ether and 100 parts by mass of isopropyl alcohol. In this solution, 297.9 parts by mass of silica fine particle dispersion liquid (manufactured by JGC Catalysts & Chemicals Co., Ltd., isopropyl alcohol dispersion sol) having an average particle diameter of 40 nm, 54 parts by mass of water and 1.8 parts by mass of formic acid Was added dropwise with stirring so that the reaction temperature did not exceed 30 ° C. After the dropwise addition, the obtained solution was heated at a bath temperature of 40 ° C. for 2 hours, and then the solution was heated at a bath temperature of 85 ° C. for 2 hours, the internal temperature was raised to 80 ° C. and heated for 1.5 hours, The solution A was obtained.

  In the obtained solution A, 4.8 parts by mass of aluminum tris (acetyl acetate) (trade name: Aluminum Chelate A (W), manufactured by Kawaken Fine Chemical Co., Ltd.) is dissolved in 125 parts by mass of methanol as an aluminum curing agent. Add 1,500 parts by weight of isopropyl alcohol and 250 parts by weight of propylene glycol monomethyl ether, stir at room temperature for 2 hours, and adjust the solid content concentration to 1% by weight with isopropyl alcohol. Thus, a coating composition was obtained. The refractive index of this coating composition was 1.36.

(Coating composition oc2)
A coating composition is prepared by diluting acrylic UV curable material (TU-2180 manufactured by JSR Corporation) containing silica particles having voids inside with methyl ethyl ketone so that the solid content concentration is 1% by mass. did. The refractive index of this coating composition was 1.37.

(Coating composition oc3)
109.0 parts by mass of methyltrimethoxysilane, 56.8 parts by mass of heptadecafluorodecyltrimethoxysilane, and 12 parts by mass of dimethyldimethoxysilane were dissolved in 300 parts by mass of diacetone alcohol and 100 parts by mass of isopropanol. In this solution, 250 parts by mass of silica particle sol (trade name MIBK-ST, manufactured by Nissan Chemical Industries, Ltd., solid content 30% by mass) dispersed in methyl isobutyl ketone and having an average particle size of 12 nm, 60 parts by mass of water And 2 parts by mass of acetic acid was added dropwise with stirring so that the reaction temperature did not exceed 30 ° C. After the dropwise addition, the obtained solution was heated at a bath temperature of 40 ° C. for 2 hours, and then the solution was heated at a bath temperature of 85 ° C. for 2 hours, the internal temperature was raised to 80 ° C. and heated for 1.5 hours, Until solution B was obtained.

  A solution obtained by dissolving 3.8 parts by mass of magnesium bis (ethylacetoacetate) in 250 parts by mass of methanol as a magnesium-based curing agent is added to the obtained solution B, and 1,700 parts by mass of isopropanol and 500 parts of diacetone alcohol are added. The coating composition was obtained by adding part by mass, stirring for 2 hours at room temperature, and adjusting the solid content concentration to 1% by mass. The refractive index of this coating composition was 1.38.

(Coating composition oc4)
A coating composition was prepared in the same manner as the coating composition oc3 except that the amount of silica particle sol added was changed from 250 parts by mass to 56 parts by mass. The refractive index of this coating composition was 1.40.

(Coating composition oc5)
Ultraviolet curable resin (containing dipentaerythritol hexaacrylate and urethane acrylate at a mass ratio of 1: 3) 77 parts by mass, silica fine particle dispersion having voids inside with an average particle size of 40 nm (manufactured by JGC Catalysts & Chemicals Co., Ltd.) Isopropyl alcohol dispersion sol) in a solid content of 20 parts by mass, and 3 parts by mass of a photopolymerization initiator (“Irgacure (registered trademark) 184” manufactured by Ciba Specialty Chemicals Co., Ltd.) are dispersed in an organic solvent (methyl ethyl ketone). Or it melt | dissolved and it adjusted so that solid content concentration might be 1 mass% with methyl ethyl ketone, and obtained the coating composition. The refractive index of this coating composition was 1.42.

(Coating composition oc6)
In a container, 20 parts by mass of ethanol was added, and 40 parts by mass of n-butyl silicate was added and stirred for 30 minutes. Then, after adding 10 mass parts of 0.1N hydrochloric acid aqueous solution, it stirred for 2 hours (hydrolysis reaction) and stored at 4 degreeC. After 24 hours, this solution was adjusted with a mixed solution of isopropyl alcohol, toluene, and n-butanol (mixing mass ratio 2: 1: 1) so that the solid concentration was 1% by mass to obtain a coating composition. . The refractive index of this coating composition was 1.44.

[Coating composition for forming hard coat layer (hc1)]
58 parts by mass of dipentaerythritol hexaacrylate, urethane acrylate oligomer (“UN-901T” from Negami Kogyo Co., Ltd .; containing 9 ethylenically unsaturated groups in the molecule), polymerization initiator (Ciba Specialty) 5 parts by mass of “Irgacure (registered trademark) 184” manufactured by Chemicals Co., Ltd. was dispersed and dissolved in an organic solvent (methyl isobutyl ketone). The refractive index of this coating composition was 1.52.

[Coating composition for forming carbon nanotube layer (cnt1)]
(Catalyst preparation example: Catalytic metal salt supported on magnesia)
2.46 g of ammonium iron citrate (Wako Pure Chemical Industries, Ltd.) was dissolved in 500 mL of methanol (Kanto Chemical Co., Ltd.). To this solution, 100.0 g of magnesium oxide (MJ-30 manufactured by Iwatani Chemical Industry Co., Ltd.) was added and vigorously stirred with a stirrer for 60 minutes to form a suspension. Concentrated to dryness at ° C. The obtained powder was heated and dried at 120 ° C. to remove methanol, and a catalyst body in which a metal salt was supported on magnesium oxide powder was obtained. The obtained solid was finely divided in a mortar, and a particle size in the range of 20 to 32 mesh (0.5 to 0.85 mm) was collected using a sieve. The iron content contained in the obtained catalyst body was 0.38% by mass. The bulk density was 0.61 g / mL.

(Example of carbon nanotube aggregate production: synthesis of carbon nanotube aggregate)
A catalyst layer was formed by taking 132 g of the solid catalyst prepared in the catalyst preparation example and introducing it onto a quartz sintered plate at the center of the reactor installed in the vertical direction. While heating the catalyst layer until the temperature in the reaction tube reaches about 860 ° C., nitrogen gas is supplied at 16.5 L / min from the bottom of the reactor toward the top of the reactor using a mass flow controller. Circulated to pass through. Thereafter, while supplying nitrogen gas, methane gas was further introduced at 0.78 L / min for 60 minutes using a mass flow controller, and the gas was passed through the catalyst body layer for reaction. The contact time (W / F) obtained by dividing the mass of the solid catalyst body by the flow rate of methane at this time was 169 minutes · g / L, and the linear velocity of the gas containing methane was 6.55 cm / sec. The quartz reaction tube was cooled to room temperature while the introduction of methane gas was stopped and nitrogen gas was passed through at 16.5 L / min.

  The heating was stopped and the mixture was allowed to stand at room temperature. After the temperature reached room temperature, the carbon nanotube-containing composition containing the catalyst body and the carbon nanotubes was taken out from the reactor.

(Purification of carbon nanotube aggregate and oxidation treatment)
The catalyst body obtained in the carbon nanotube aggregate production example and the carbon nanotube-containing composition containing carbon nanotubes were stirred for 1 hour in 4.8 mL of 4.8N hydrochloric acid aqueous solution using 130 g of the carbon nanotube-containing composition. The carrier MgO was dissolved. The resulting black suspension was filtered, and the filtered material was again poured into 400 mL of a 4.8N hydrochloric acid aqueous solution, treated with MgO, and collected by filtration. This operation was repeated 3 times (de-MgO treatment). Thereafter, the carbon nanotube-containing composition was stored in a wet state containing water after washing with ion-exchanged water until the suspension of the filtered material became neutral. At this time, the mass of the wet carbon nanotube-containing composition containing water was 102.7 g (concentration of carbon nanotube: 3.12% by mass).

  About 300 times as much concentrated nitric acid (manufactured by Wako Pure Chemical Industries, Ltd., first grade, Assay 60-61 mass%) was added to the dry mass of the obtained carbon nanotube-containing composition in the wet state. Thereafter, the mixture was heated to reflux with stirring in an oil bath at about 140 ° C. for 25 hours. After heating to reflux, a nitric acid solution containing the carbon nanotube-containing composition was diluted with ion-exchanged water three times and suction filtered. After washing with ion-exchanged water until the suspension of the filtered material became neutral, a wet carbon nanotube aggregate containing water was obtained. At this time, the mass of the wet carbon nanotube composition containing water was 3.351 g (concentration of carbon nanotube: 5.29% by mass).

(Preparation of carbon nanotube dispersion)
1.04 g of the obtained carbon nanotube aggregate in a wet state (25 mg in terms of dry mass), 6% by mass sodium carboxymethyl cellulose (Dell Daiichi Kogyo Seiyaku Co., Ltd., Selogen 7A (weight average molecular weight: 19,0000)) To a dispersion obtained by adding 6.7 g of zirconia beads (manufactured by Toray Industries, Inc., Treceram, bead size: 0.8 mm) to a container, add a 28 mass% aqueous ammonia solution (manufactured by Kishida Chemical Co., Ltd.) to adjust the pH. Adjusted to 10. This container was shaken for 2 hours using a vibration ball mill (manufactured by Irie Shokai Co., Ltd., VS-1, frequency: 1,800 cpm (60 Hz)) to prepare a carbon nanotube paste.

  Next, this carbon nanotube paste is diluted with ion-exchanged water so that the concentration of carbon nanotubes is 0.15% by mass, and the pH is adjusted to 10 by adding 28% by mass aqueous ammonia again to 10 g of the diluted solution. did. The aqueous solution was subjected to dispersion treatment under ice-cooling for 1.5 minutes (1 kW · min / g) with an output of an ultrasonic homogenizer (manufactured by Ieda Trading Co., Ltd., VCX-130) at 20 W. The liquid temperature during dispersion was adjusted to 10 ° C. or lower. The obtained liquid was centrifuged at 10,000 G for 15 minutes using a high-speed centrifuge (Tomy Seiko Co., Ltd., MX-300) to obtain 9 g of a carbon nanotube dispersion.

(Preparation of carbon nanotube-containing coating composition)
Ion exchange water was added to the carbon nanotube dispersion liquid to obtain a coating composition (cnt1) with a solid content concentration of 0.04% by mass.

[Example 1]
A conductive laminate was prepared in the following manner.

<Production of polyethylene terephthalate film (PET film) having a resin layer>
PET pellets (intrinsic viscosity 0.63 dl / g) substantially free of externally added particles are sufficiently vacuum-dried, then supplied to an extruder, melted at 285 ° C., extruded from a T-shaped die into a sheet shape, It was wound around a mirror-casting drum having a surface temperature of 25 ° C. using an electric application casting method and cooled and solidified. This unstretched film was heated to 90 ° C. and stretched 3.4 times in the longitudinal direction to obtain a uniaxially stretched film. After performing corona discharge treatment in air on both surfaces of this uniaxially stretched film, coating composition a1 for forming a resin layer on one surface (first surface) of the uniaxially stretched film, the other surface (second surface) ) Was also coated with a coating composition a1 for forming the resin layer B.

  Next, the uniaxially stretched film coated with the resin layer forming coating composition on both sides is held with a clip, guided to a preheating zone, dried at an ambient temperature of 75 ° C., raised to 110 ° C. using a radiation heater, and again After drying at 90 ° C., the film is continuously stretched 3.5 times in the width direction in a heating zone at 120 ° C., followed by heat treatment for 20 seconds in the heating zone at 220 ° C. A film was prepared. This PET film is a PET film having resin layers on both sides.

  The thickness of this PET film was 100 μm, the thickness of the resin layer provided on the first surface was 80 nm, and the thickness of the resin layer B provided on the second surface was 80 nm.

  The refractive index of the PET film was 1.65, the refractive index of the resin layer on the first surface was 1.58, and the refractive index of the resin layer B on the second surface was 1.58.

  In addition, the refractive index of PET film measured the refractive index of the PET film manufactured on the conditions similar to the above except not laminating | stacking a resin layer on both surfaces, and made the value the refractive index of PET film.

<Lamination of hard coat layer>
A coating composition (hc1) for forming a hard coat layer is applied on the resin layer B on the second surface of the PET film prepared above by a gravure coating method, dried at 90 ° C., and then irradiated with ultraviolet rays of 500 mJ / A hard coat layer was formed by curing with irradiation of cm ² . This hard coat layer had a thickness of 2.5 μm.

<Lamination of undercoat layer>
After applying the coating composition uc1 for forming the undercoat layer onto the resin layer on the first surface of the PET film with the hard coat layer laminated as described above, the dry thickness is 40 nm by the slot die coating method. And dried at 90 ° C. for 1 minute to form an undercoat layer.

<Formation of carbon nanotube layer>
On the undercoat layer laminated above, a coating composition (cnt1) for forming a carbon nanotube layer was applied by a slot die coating method so that the solid content was 15 mg / m ^2. A carbon nanotube layer was formed by drying at 1 ° C. for 1 minute.

<Application of overcoat layer>
A coating composition oc1 for forming an overcoat layer was applied on the carbon nanotube layer laminated as described above so as to have a dry thickness of 60 nm by a slot die coating method, and then dried at 125 ° C. for 1 minute. The overcoat layer was laminated.

[Examples 2 to 17 and Comparative Examples 1 to 6]
In Example 1, except that the coating composition for forming the undercoat layer and / or the coating composition for forming the overcoat layer was changed as shown in Table 1, it was conducted in the same manner as in Example 1. A conductive laminate was produced.

The overcoat layer-forming coating compositions oc2 and oc5 are of an ultraviolet curable type, and when these coating compositions were used, the coating and drying were performed by irradiation with ultraviolet rays of 500 mJ / cm ² and cured.

[Evaluation]
About the Example produced above and the comparative example, the luminous reflectance of the conductive layer surface was evaluated. The results are shown in Table 1.

  From the results in Table 1, it can be seen that all of the examples of the present invention have small luminous reflectance.

  On the other hand, in Comparative Examples 1 to 6, the refractive index of any one of the undercoat layer and the overcoat layer is out of the range of the present invention, and the luminous reflectance is relatively high.

[Examples 21 to 35]
In Example 1, a conductive laminate was produced in the same manner as in Example 1 except that the thicknesses of the undercoat layer and the overcoat layer were changed as shown in Table 1.

[Evaluation]
About the Example produced above, the luminous reflectance of the conductive layer surface was evaluated. The results are shown in Table 2.

  From the results of Table 2, the luminous reflectance is relatively reduced by setting the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat layer to be in the range of 75 to 125 nm, and is further reduced by setting the thickness to 80 to 120 nm. It can be seen that the reflectance is relatively small.

[Example 41]
In the production of the polyethylene terephthalate film (PET film) having the resin layer of Example 1, the resin layer forming coating composition a1 laminated on the first surface is changed to the coating composition a2, and the thickness is changed to 20 nm. Except for the above, a polyethylene terephthalate film (PET film) having a resin layer was produced in the same manner as in Example 1, and a hard coat layer was laminated on the resin layer on the second surface of this PET film in the same manner as in Example 1. Further, an undercoat layer, a carbon nanotube layer, and an overcoat layer were laminated on the resin layer on the first surface of the PET film in the same manner as in Example 1 to produce a conductive laminate.

[Examples 42 to 60]
In Example 41, except that the coating composition for forming the undercoat layer and / or the coating composition for forming the overcoat layer was changed as shown in Table 3, it was conducted in the same manner as in Example 41. A conductive laminate was produced.

The overcoat layer-forming coating compositions oc2 and oc5 are of an ultraviolet curable type, and when these coating compositions were used, the coating and drying were performed by irradiation with ultraviolet rays of 500 mJ / cm ² and cured.

[Evaluation]
About the Example produced above, the luminous reflectance of the conductive layer surface was evaluated. The results are shown in Table 3.

  From the results of Table 3, it can be seen that the luminous reflectance is further reduced by setting the refractive index of the resin layer provided between the base material and the undercoat layer to be in the range of 1.61-1.70.

[Example 61]
In the production of the polyethylene terephthalate film (PET film) having the resin layer of Example 1, the resin layer forming coating composition a1 laminated on the first surface is changed to the coating composition a3, and the thickness is changed to 40 nm. Except for the above, a polyethylene terephthalate film (PET film) having a resin layer was produced in the same manner as in Example 1, and a hard coat layer was laminated on the resin layer on the second surface of this PET film in the same manner as in Example 1. Further, an undercoat layer, a carbon nanotube layer, and an overcoat layer were laminated on the resin layer on the first surface of the PET film in the same manner as in Example 1 to produce a conductive laminate.

[Example 62]
In the production of the polyethylene terephthalate film (PET film) having the resin layer of Example 1, it is the same as Example 1 except that the coating composition a1 for resin layer formation laminated on the first surface is changed to the coating composition a4. A polyethylene terephthalate film (PET film) having a resin layer was prepared, a hard coat layer was laminated on the resin layer on the second surface of the PET film in the same manner as in Example 1, and the first surface of the PET film was further laminated. An undercoat layer, a carbon nanotube layer, and an overcoat layer were laminated on the resin layer in the same manner as in Example 1 to produce a conductive laminate.

[Evaluation]
About Examples 61 and 62 produced above, the luminous reflectance of the conductive layer surface was evaluated. The results are shown in Table 4.

  In Example 61, the refractive index of the resin layer provided between the base material and the undercoat layer is in the range of 1.61 to 1.70, and the luminous reflectance is further reduced.

  In Example 62, the refractive index of the resin layer provided between the base material and the undercoat layer is less than 1.55, and Example 1 (refractive index of the resin layer 1.58) and Example 61 (resin layer) The refractive index is relatively higher than the refractive index of 1.63).

  That is, when the refractive index of the resin layer is 1.55 to 1.70, the luminous reflectance is reduced, and when the refractive index of the resin layer is 1.61 to 1.70, the luminous reflectance is reduced. It gets smaller.

[Example 71]
A triacetyl cellulose (TAC) film having a thickness of 80 μm (trade name “KC8UY”, refractive index 1.49, manufactured by Konica Minolta Opto Co., Ltd.) having a thickness of 80 μm was used as the substrate. As for this base material, the resin layer is not laminated | stacked. A hard coat layer is laminated on one side of the substrate in the same manner as in Example 1, and an undercoat layer, a carbon nanotube layer, and an overcoat layer are laminated on the other side in the same manner as in Example 1 to provide conductivity. A laminate was produced.

[Examples 72 to 73 and Comparative Examples 7 to 8]
In Example 71, except that the coating composition for forming the undercoat layer and / or the coating composition for forming the overcoat layer was changed as shown in Table 5, it was conducted in the same manner as in Example 71. A conductive laminate was produced.

The overcoat layer-forming coating composition oc2 is of an ultraviolet curable type, and when these coating compositions were used, they were cured by irradiation with ultraviolet rays of 500 mJ / cm ² after coating and drying.

[Evaluation]
About the Example produced above and the comparative example, the luminous reflectance of the conductive layer surface was evaluated. The results are shown in Table 5.

  From the results of Table 5, it can be seen that all of the examples of the present invention have low luminous reflectance.

  On the other hand, in Comparative Examples 7 and 8, the refractive index of either the undercoat layer or the overcoat layer is out of the range of the present invention, and the luminous reflectance is relatively high.

  Further, when Examples 71 to 73 using a TAC film having a refractive index of 1.49 and Examples 1, 7, and 11 using a PET film having a refractive index of 1.65 are compared, the refractive index is as a substrate. It can be seen that the luminous reflectance is relatively small when the 1.65 PET film is used. That is, by using a base material having a refractive index of 1.61 to 1.70, the luminous reflectance of the conductive layer surface can be further reduced.

[Example 81]
The example which applied the electroconductive laminated body produced in Example 1 to both the upper electrode and lower electrode of a resistive film type touch panel is shown below.

  Wiring was applied to the conductive layer of the conductive laminate of Example 1 with silver paste to form an upper electrode. Similarly, a spacer was provided with a UV curable resin on the conductive layer side of the conductive laminate of Example 1, and wiring was further provided with a silver paste to form a lower electrode. The upper electrode and the lower electrode were bonded with a double-sided tape, a flexible printed circuit was connected, and a resistive film type touch panel was produced.

  When this resistive touch panel was touch-operated with a touch pen, the upper electrode and the lower electrode were in contact with each other, and coordinate information of the touch-operated location could be output. The total light transmittance of this touch panel was 79%, which was a sufficient transmittance as a touch panel.

[Example 82]
A resistive touch panel was produced in the same manner as in Example 81 except that the conductive laminate was changed to the conductive laminate of Example 41.

  When this resistive touch panel was touch-operated with a touch pen, the upper electrode and the lower electrode were in contact with each other, and coordinate information of the touch-operated location could be output. The total light transmittance of this touch panel was 80%, which was a sufficient transmittance as a touch panel.

[Comparative Example 9]
A resistive touch panel was produced in the same manner as in Example 81 except that the conductive laminate was changed to the conductive laminate of Comparative Example 1.

  When this resistive touch panel was touch-operated with a touch pen, the upper electrode and the lower electrode were in contact with each other, and coordinate information of the touch-operated location could be output. The total light transmittance of this touch panel is 76%, which is lower than that of Examples 81 and 82.

DESCRIPTION OF SYMBOLS 1 Conductive laminated body which comprises upper electrode 2 Conductive laminated body which comprises lower electrode 3 Spacer 4 Touch pen 5 Space (air layer)
DESCRIPTION OF SYMBOLS 10 Conductive layer 11 Base material 12 Undercoat layer 13 Carbon nanotube layer 14 Overcoat layer 15 Hard coat layer 21 Base material 22 Conductive layer

Claims (7)

  A conductive laminate having an undercoat layer, a carbon nanotube layer, and an overcoat layer in order from the base material side on at least one surface of the base material, wherein the refractive index of the undercoat layer is 1.40 or less and the overcoat A conductive laminate having a refractive index of a layer of 1.43 or less.   The conductive laminate according to claim 1, wherein the total thickness of the undercoat layer, the carbon nanotube layer, and the overcoat layer is 75 to 125 nm.   The electroconductive laminated body of Claim 1 or 2 whose refractive index of a base material is 1.61-1.70.   The electroconductive laminated body of Claim 3 whose base material is a polyethylene terephthalate film.   The conductive laminate according to claim 4, comprising a resin layer having a refractive index of 1.55 to 1.70 between the base material and the undercoat layer.   The conductive laminate according to claim 5, wherein the resin layer has a refractive index of 1.61 to 1.70.   A touch panel using the conductive laminate according to claim 1.

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