WO2023120620A1

WO2023120620A1 - Touch panel and method for manufacturing touch panel

Info

Publication number: WO2023120620A1
Application number: PCT/JP2022/047276
Authority: WO
Inventors: 惇 ▲桑▼原; 正彦鳥羽; 周平米田; 繁山木
Original assignee: 株式会社レゾナック
Priority date: 2021-12-24
Filing date: 2022-12-22
Publication date: 2023-06-29
Also published as: TW202333030A

Abstract

A touch panel having a curved surface region and comprising at least two layers, which are a film-like base material and a transparent conductive pattern film that is formed on at least one surface of the base material, wherein the transparent conductive pattern film contains conductive fibers, the aperture ratio thereof is 40-70%, an electrode row formed from a conductive region and a non-conductive region is provided, an input region formed by the electrode row of the transparent conductive pattern film is included, at least part of the electrode row is disposed in the curved surface region, and a lead-out line connected to the electrode row is provided.

Description

Touch panel and touch panel manufacturing method

The present invention relates to a touch panel and a method for manufacturing a touch panel.

A touch panel is used as an input device. Conventionally, ITO (indium tin oxide) or the like has been used as an electrode for detecting a touch position, but it lacks flexibility and is prone to cracks. Therefore, there is known a touch panel that uses a conductive film made of metal mesh or the like and having an aperture ratio of 90% or more instead of ITO or the like (see Patent Document 1).
In addition, as a result of the development of conductive materials and electrode materials for touch panels, the amount of conductive inorganic nanowires used was reduced, surface resistance variations were suppressed in a wide range of surface resistance values, and conductive materials with excellent transparency were achieved. In order to provide a conductive film, the ratio of the area occupied by the conductive inorganic nanowires in the plane of the conductive layer is 5 to 30%, and the surface resistance value of the conductive layer is 1.0×10 ² to 1.0×10 ^{6 .} Ω/□ has been proposed (see Patent Document 2).

WO2016/075737 JP-A-2013-924

When using a metal mesh as a detection electrode of a touch panel, a moiré pattern may appear on the panel. In addition, in the case of a conductive film with a high aperture ratio, the electrode is thin and disconnection is likely to occur. In particular, when three-dimensional molding is performed to obtain a touch panel having a curved surface area, the resistance increases and the electrode disconnection occurs, resulting in a touch panel. sometimes did not work.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a touch panel that does not generate a moire pattern and can be driven even if the touch panel has a curved surface area, a method for manufacturing the same, an input/output integrated display device and an in-vehicle display equipped with this touch panel. and

Thus, specific embodiments of the invention are as follows.
<1> a film-like substrate;
A touch panel having a curved region, comprising at least two layers of a transparent conductive pattern film formed on at least one surface of the base material,
The transparent conductive pattern film contains conductive fibers, has an aperture ratio of 40% or more and 70% or less, and has an electrode array formed of a conductive region and a non-conductive region, and the transparent conductive pattern film including an input region formed by an electrode column of
A touch panel, wherein at least a part of the electrode array is arranged in the curved surface region and includes a lead line connected to the electrode array.
<2> The touch panel according to <1>, wherein the conductive fibers include metal nanowires having an average diameter of 1 nm or more and 500 nm or less.
<3> The touch panel according to <1> or <2>, wherein the conductive fibers have an average length of 1 μm or more and 100 μm or less, and an average aspect ratio of 5 or more.
<4> The touch panel according to any one of <1> to <3>, wherein the conductive fibers contain one or more metals selected from the group consisting of gold, silver, copper and aluminum.

<5> The touch panel according to <1>, wherein the substrate is made of a transparent thermoplastic resin film, and the transparent conductive pattern film contains a binder resin and metal nanowires.
<6> The binder resin is a polymer or cellulose resin containing 70 mol% or more of N-vinylacetamide (NVA) as a monomer unit, has a protective film formed on the transparent conductive pattern film, and the protective The touch panel according to <5>, wherein the film contains a resin component, and 94% by mass or more of the resin component is derived from a thermoplastic resin.
<7> The touch panel according to <5>, wherein the transparent thermoplastic resin film is a polycarbonate film.
<8> The touch panel according to <6> or <7>, wherein the binder resin is poly-N-vinylacetamide.
<9> The touch panel according to any one of <6> to <8>, wherein the resin component constituting the protective film is derived from a thermoplastic resin containing carboxy group-containing polyurethane or ethyl cellulose.
<10> The resin component constituting the protective film is derived from a polyurethane containing a carboxy group and an epoxy resin having two or more epoxy groups in one molecule, and has two or more epoxy groups in one molecule. The content of the epoxy resin is more than 0% by mass and 6% by mass or less in the resin component, and the carboxyl group (COOH) of the carboxyl group-containing polyurethane has two or more epoxy groups in one molecule. The touch panel according to <9>, wherein the epoxy group (Ep) molar ratio (Ep/COOH) of the epoxy resin having is more than 0 and 0.02 or less.
<11> The touch panel according to any one of <1> to <10>, wherein there are a plurality of input areas formed by the electrode arrays of the transparent conductive pattern film, and each input area has a different shape.
<12> A first input area and a second input area exist as the input areas, and driving of the touch panel by operation in the first input area is also possible by operation in the second input area <1> The touch panel according to any one of <11>.
<13> The touch panel according to any one of <1> to <12>, wherein the curved surface region is a three-dimensional curved surface.

<14> As the transparent conductive pattern film, two types of a first transparent conductive pattern film and a second transparent conductive pattern film are provided, and the first transparent conductive pattern film and the second transparent conductive pattern film are the The method for manufacturing a touch panel according to any one of <1> to <13>, including a step of forming the curved surface regions by heating the transparent conductive film laminates laminated on both main surfaces of the substrate.
<15> As the transparent conductive pattern film, two types of a first transparent conductive pattern film and a second transparent conductive pattern film are provided, and the first transparent conductive pattern film is one of the main substrates of the first base material. A first transparent conductive film laminate formed only on one surface, and a second transparent conductive film laminate formed on only one main surface of the second base material with the second transparent conductive pattern film. The method for manufacturing a touch panel according to any one of <1> to <13>, including a step of forming the curved surface region by heat forming after joining and integrating , through an adhesive layer.
<16> Forming a first transparent conductive pattern film having the electrode array and a second transparent conductive pattern film having the electrode array by laser etching a transparent conductive film containing metal nanowires <14>> or the method for manufacturing a touch panel according to <15>.
<17> An input/output integrated display device comprising a display and the touch panel according to any one of <1> to <13> provided on the display.
<18> An in-vehicle display comprising the input/output integrated display device according to <17>.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide a touch panel that does not generate a moire pattern and can be driven even though it has a curved surface area, a manufacturing method thereof, and an input/output integrated display device and an in-vehicle display equipped with this touch panel. .

1 is an exploded perspective view schematically showing the layer structure of a curved region of a display (input/output integrated display device) 12 incorporating a touch panel of one embodiment. FIG. FIG. 2 is a cross-sectional view showing an example of the layer structure of the touch panel of the present invention; FIG. 4 is a schematic diagram showing an example of a method of connecting electrode rows and lead wires in the present invention. FIG. 4 is a cross-sectional view showing another layer configuration example of the touch panel of the present invention; FIG. 5 is a diagram showing an example of the shape of the curved area of the touch panel of the present invention; FIG. 5 is a diagram showing another shape example of the curved surface area of the touch panel of the present invention; FIG. 4 is a diagram showing an example of a shape in which the touch panel of the present invention is used for a curved area of a center console in a vehicle;

Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.
In this disclosure, unless otherwise specified, the descriptions of "00 to 00" and "00 to 00" that represent numerical ranges mean numerical ranges that include the stated upper and lower limits.
A touch panel according to an embodiment has a curved region composed of at least two layers of a film-like base material and a transparent conductive pattern film formed on at least one surface of the base material. The transparent conductive pattern film contains conductive fibers, has an aperture ratio of 40% or more and 70% or less, has an electrode array formed of a conductive region and a non-conductive region, and the transparent conductive pattern It includes an input area formed by an array of membrane electrodes. At least a part of the electrode row is arranged in the curved surface region and includes a lead wire connected to the electrode row.
"Base material"
The base material is in the form of a film (including a sheet), and forms a curved area by three-dimensional molding or the like as described later. Here, the curved surface refers to a non-planar state. In the present disclosure, not only a flat film that is simply curved but also a three-dimensional curved surface can be suitably used. A three-dimensional curved surface means a curved surface that cannot be formed by deforming a plane. The base material of the present disclosure has at least a portion thereof formed into a curved surface.
Although the substrate may be colored, it is preferable that the total light transmittance (transparency to visible light) is high, and a transparent substrate having a total light transmittance of 75% or more is preferable, particularly 80% or more. is preferred. In the present application, "transparent" means a total light transmittance of 75% or more.
The substrate that can be used is a thermoplastic resin film, and examples of the thermoplastic resin film include polyester (polyethylene terephthalate [PET], polyethylene naphthalate [PEN], etc.), polycarbonate, acrylic resin (polymethyl methacrylate [PMMA], etc.). ), and resin films such as cycloolefin polymers. The resin film is preferably an amorphous thermoplastic resin film having good moldability for three-dimensional molding. Therefore, among the resin films, amorphous polycarbonate and cycloolefin polymer are preferable, and polycarbonate is more preferable. Polycarbonates have --[O--R--OCO]--units (where R contains an aliphatic group, an aromatic group, or both an aliphatic and an aromatic group, as well as straight It is not particularly limited as long as it includes a chain structure or a branched structure). Cycloolefin polymers include hydrogenated ring-opening metathesis polymerization type cycloolefin polymers of norbornene (ZEONOR (registered trademark, manufactured by Nippon Zeon Co., Ltd.), ZEONEX (registered trademark, manufactured by Nippon Zeon Co., Ltd.), ARTON (registered trademark, JSR stock company), etc.), or norbornene/ethylene addition copolymer type cycloolefin polymers (APEL (registered trademark, manufactured by Mitsui Chemicals, Inc.), TOPAS (registered trademark, manufactured by Polyplastics Co., Ltd.)) can be used. As the polycarbonate, specifically, Iupilon (registered trademark, manufactured by Mitsubishi Gas Chemical Company, Inc.) or Panlite (registered trademark, manufactured by Teijin Limited) can be used. Among these, those having a glass transition temperature (Tg) of 90° C. or higher and 170° C. or lower are preferable because they can withstand heating in the wiring manufacturing process, and those having a glass transition temperature (Tg) of 125° C. or higher and 160° C. or lower are more preferable. The thickness is preferably 10 μm or more and 500 μm or less, more preferably 25 μm or more and 250 μm or less, and even more preferably 40 μm or more and 150 μm or less. When the thickness is 40 μm or more, it is possible to suppress the penetration of pulsed laser light (hereinafter sometimes referred to as pulsed laser), which will be described later, even in a transparent resin film. Therefore, when transparent conductive films are formed on both sides of a transparent resin film and each transparent conductive film is processed using a pulse laser, it is preferable to use a substrate having a thickness of 40 μm or more. The thicker the resin film, the higher the effect of suppressing penetration of the pulsed laser beam. More preferably, the thickness of the resin film is 45 μm or more and 200 μm or less, more preferably 50 μm or more and 150 μm or less, and still more preferably 100 μm or more and 125 μm or less. When a transparent conductive film is formed on one side of a transparent conductive base material and a pair of transparent conductive film laminates processed using a pulse laser are laminated and used, the transparent conductive film is formed on the back side of the transparent conductive base material. Since the transparent conductive film on the back side is not damaged by penetration of the pulsed laser light, a transparent resin film having a thickness of less than 40 μm can be applied.
Regarding the distinction between "film" and "sheet", an object having a thickness of 200 μm or less is often called a “film”, and an object having a thickness of more than 200 μm is often called a “sheet”. However, "film" and "sheet" are not clearly distinguished, and "film" in the present specification includes "sheet".

《Transparent conductive pattern film》
A transparent conductive pattern film is a film containing conductive fibers. The transparent conductive pattern film has electrode rows formed from conductive regions and non-conductive regions, and has an aperture ratio of 40% or more and 70% or less.
Examples of the conductive fibers that can be used include metal nanowires, carbon fibers, and carbon nanotubes. Carbon nanotubes are highly extensible, and metal nanowires are flexible materials. Metal nanowires are preferable from the viewpoint of transparency.
Also, when metal nanowires are used as conductive fibers, 15% strain can be achieved by using conductive ink combined with a specific binder resin (poly-N-vinylacetamide (PNVA (registered trademark)) described later). It has been confirmed in advance that it is possible to form wiring that does not cause problems such as disconnection even if it is added. Moreover, since poly-N-vinylacetamide (PNVA (registered trademark)) has hygroscopicity, it is preferable to provide a protective film covering the surface thereof. A metal nanowire is a metal whose diameter is on the order of nanometers, and is a conductive material having a wire-like shape. In one embodiment, metal nanotubes, which are electrically conductive materials having porous or non-porous tubular shapes, may be used with (in admixture with) or in place of metal nanowires. In the present disclosure, both "wire" and "tube" are linear, but the former means that the center is not hollow and the latter means that the center is hollow, and their properties are flexible and flexible. It may be flexible or rigid. In the present disclosure, the former is referred to as "narrowly defined metal nanowire" and the latter is referred to as "narrowly defined metal nanotube", and "metal nanowire" encompasses both narrowly defined metal nanowires and narrowly defined metal nanotubes. A narrowly defined metal nanowire and a narrowly defined metal nanotube may be used alone or in combination.

The transparent conductive pattern film is conductive by being formed on the transparent substrate so that the conductive fibers have intersections, forming conductive regions. In addition, since there is a region through which light can pass through the opening where the conductive fiber is not present, the film has transparency. When the conductive fibers are metal nanowires, the metal nanowires preferably form a nanostructure network having intersections, and more preferably form a nanostructure network in which at least a portion of the intersections are fused. It can be confirmed by observing an electron beam diffraction pattern with a transmission electron microscope (TEM) that the intersections of the metal nanowires are fused. Specifically, the electron beam diffraction patterns of the metal nanowires that are sufficiently distant from the intersections of the metal nanowires and the intersections of the metal nanowires are analyzed, and the crystal structures of the two are different (solvent Recrystallization occurs due to heating for drying, etc., and the crystal structure changes).

A known manufacturing method can be used as a method for manufacturing metal nanowires. For example, silver nanowires can be synthesized by reducing silver nitrate in the presence of polyvinylpyrrolidone using the Poly-ol method (see Chem. Mater., 2002, 14, 4736). Gold nanowires can also be synthesized by reducing chloroauric acid hydrate in the presence of polyvinylpyrrolidone (see J. Am. Chem. Soc., 2007, 129, 1733). Techniques for large-scale synthesis and purification of silver nanowires and gold nanowires are described in detail in WO2008/073143 and WO2008/046058. A gold nanotube having a porous structure can be synthesized by reducing a chloroauric acid solution using a silver nanowire as a template. The silver nanowires used as the template dissolve into the solution due to the redox reaction with chloroauric acid, resulting in the formation of gold nanotubes having a porous structure (J. Am. Chem. Soc., 2004, 126, 3892- 3901).

The average diameter of the metal nanowires is preferably 1-500 nm, more preferably 5-200 nm, even more preferably 5-100 nm, and particularly preferably 10-50 nm. The average length of the long axis of the metal nanowires is preferably 1 to 100 μm, more preferably 1 to 80 μm, even more preferably 2 to 70 μm, and particularly preferably 5 to 50 μm. The metal nanowires preferably have an average diameter and an average major axis length that satisfy the above ranges, and an average aspect ratio of more than 5, more preferably 10 or more, and more preferably 100 or more. It is preferably 200 or more, and particularly preferably 200 or more. In the present disclosure, the aspect ratio is a value obtained by a/b, where b is the average diameter of the metal nanowires, and a is the average length of the long axis. a and b are measured using a scanning electron microscope (SEM) and an optical microscope. Specifically, b (average diameter) is a measured value obtained by measuring the dimensions of 100 arbitrarily selected metal nanowires using a field emission scanning electron microscope JSM-7000F (manufactured by JEOL Ltd.). is determined as the arithmetic mean of a (average length of the long axis) is obtained by measuring the dimensions of 100 arbitrarily selected metal nanowires using a shape measuring laser microscope VK-X200 (manufactured by Keyence Corporation), and calculating the obtained measurement value. Determined as an average value.

Materials for metal nanowires include, for example, at least one selected from the group consisting of gold, silver, platinum, copper, nickel, iron, cobalt, zinc, ruthenium, rhodium, palladium, cadmium, osmium, and iridium, and these metals. and alloys in which The metal nanowires preferably contain at least one of gold, silver, copper and aluminum because a transparent conductive film having low sheet resistance and high total light transmittance can be obtained. Since these metals have high conductivity, it is possible to reduce the surface density of the metals in the transparent conductive film when obtaining a predetermined sheet resistance, so that a high total light transmittance can be achieved. The metal nanowires more preferably contain at least one of gold and silver, and are most preferably silver nanowires.

A transparent conductive pattern film usually contains conductive fibers and a binder resin. As the binder resin, generally, those having transparency and excellent workability can be used. When using metal nanowires produced by the polyol method as conductive fibers, from the viewpoint of compatibility with the production solvent (polyol), it is soluble in alcohol, water, or a mixed solvent of alcohol and water. It is preferable to use a binder resin having a In one embodiment, the binder resin comprises at least one of poly-N-vinylacetamide (PNVA®), N-vinylacetamide copolymer, and cellulosic resin. As the binder resin, poly-N-vinylacetamide (PNVA (registered trademark)), N-vinylacetamide copolymer, or cellulose resin may be used alone, or a plurality of these may be used in combination. good too. Cellulose-based resins may be used alone, but may be used in combination of multiple types.
Considering that it is preferable to use a binder resin with high heat resistance from the viewpoint of post-processing, poly-N-vinylacetamide (PNVA (registered trademark)) is more preferable.

Poly-N-vinylacetamide is a homopolymer of N-vinylacetamide (NVA). A copolymer containing 70 mol % or more of N-vinylacetamide (NVA) as a monomer unit can be used as the N-vinylacetamide copolymer. Monomers copolymerizable with NVA include, for example, N-vinylformamide, N-vinylpyrrolidone, acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, acrylamide, and acrylonitrile. When the content of the copolymerization component increases, the sheet resistance of the resulting transparent conductive film tends to increase, the miscibility with the metal nanowires or the adhesion to the substrate tends to decrease, and the heat resistance (thermal decomposition initiation temperature) Therefore, the monomer unit derived from N-vinylacetamide is preferably contained in the polymer at 70 mol% or more, more preferably 80 mol% or more, and 90 mol% or more. is more preferred. The weight-average molecular weight based on the absolute molecular weight of poly-N-vinylacetamide and N-vinylacetamide copolymer is preferably 30,000 to 4,000,000, more preferably 100,000 to 3,000,000, and 300,000 to 1,500,000. 10,000 is more preferable. The absolute molecular weights of poly-N-vinylacetamide and N-vinylacetamide copolymers are measured by the following method.

《Absolute molecular weight measurement》
The binder resin is dissolved in the following eluent and left to stand for 20 hours. The concentration of the binder resin in this solution is 0.05 mass %.
The solution is filtered through a 0.45 μm membrane filter, the molecular weight of the filtrate is measured by GPC-MALS, and the weight average molecular weight is calculated based on the absolute molecular weight under the following conditions.
GPC: Shodex (registered trademark) SYSTEM21 manufactured by Showa Denko K.K.
Column: TSKgel (registered trademark) G6000PW manufactured by Tosoh Corporation
Column temperature: 40°C
Eluent: 0.1 _mol /L _NaH2PO4 _aqueous solution +0.1 mol/L _Na2HPO4 aqueous solution Flow rate: 0.64 mL/min
Sample injection volume: 100 μL
MALS detector: Wyatt Technology Corporation, DAWN® DSP
Laser wavelength: 633nm
Multi-angle fitting method: Berry method

Cellulose-based resins are linear polymers consisting of six-membered ether rings covalently linked by so-called glycosidic bonds, including ether groups. Cellulose itself does not dissolve in water, alcohol, or mixed solvents of alcohol and water, but some modified cellulose derivatives dissolve in water, alcohol, or mixed solvents of alcohol and water. The cellulose resin is not particularly limited as long as it is soluble in water, alcohol, or a mixed solvent of alcohol and water, but cellulose ether can be used. Cellulose ethers include, for example, alkyl cellulose (e.g., C1-4 alkyl cellulose such as methyl cellulose and ethyl cellulose), hydroxyalkyl cellulose (e.g., hydroxy C1-4 alkyl cellulose such as hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose), hydroxy Alkylalkylcelluloses (eg, hydroxyC2-4alkylC1-4alkylcelluloses such as hydroxypropylmethylcellulose), carboxyalkylcelluloses (eg, carboxymethylcellulose), and alkyl-carboxyalkylcelluloses (eg, methylcarboxymethylcellulose). These can be used individually or in combination of 2 or more types. Among these, it is preferable to use methyl cellulose or ethyl cellulose from the viewpoint of solubility in the above solvent and environmental resistance (moisture resistance). The weight average molecular weight of the cellulose resin is preferably 100,000 to 200,000. In the present disclosure, the weight-average molecular weight of the cellulose resin is a polyethylene oxide-equivalent value measured by gel permeation chromatography (hereinafter referred to as GPC).

A transparent conductive film (entirely conductive region: so-called solid film) for producing a transparent conductive pattern film is printed on at least one main surface of a substrate with a conductive ink containing conductive fibers, a binder resin and a solvent. and the like, and the solvent can be removed by drying.
The solvent used for the conductive ink is not particularly limited as long as the conductive fiber is well dispersed and the solvent dissolves the binder resin but does not dissolve the substrate. When using metal nanowires produced using the polyol method, it is preferable to use alcohol, water, or a mixed solvent of alcohol and water from the viewpoint of compatibility with the production solvent (polyol). It is more preferable to use a mixed solvent of alcohol and water because the drying speed of the binder resin can be easily controlled. Alcohols are saturated monohydric alcohols (methanol, ethanol, normal propanol and isopropanol) having 1 to 3 carbon atoms represented by C _n H _2n+1 OH (n is an integer of 1 to 3) [hereinafter simply “carbon atoms Saturated monohydric alcohol with a number of 1 to 3”. ], and more preferably contains at least 40% by mass of saturated monohydric alcohol having 1 to 3 carbon atoms in all alcohols. The use of a saturated monohydric alcohol having 1 to 3 carbon atoms facilitates drying of the solvent, which is advantageous in terms of the process. Alcohols other than saturated monohydric alcohols having 1 to 3 carbon atoms can be used in combination as alcohols. Examples of alcohols other than saturated monohydric alcohols having 1 to 3 carbon atoms include ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. be done. By using these alcohols together with a saturated monohydric alcohol having 1 to 3 carbon atoms, the drying rate of the solvent can be adjusted. The total alcohol content in the mixed solvent is preferably 5 to 90% by mass. If the content of alcohol in the mixed solvent is 5% by mass or more or 90% by mass or less, it is easy to suppress the occurrence of striped patterns (coating spots) when the conductive ink is coated.

The conductive ink can be produced by stirring and mixing the binder resin, conductive fibers and solvent with a rotation or revolution stirrer or the like. The content of the binder resin contained in the conductive ink is preferably in the range of 0.01 to 1.0% by mass. The content of the conductive fibers contained in the conductive ink is preferably in the range of 0.01 to 1.0% by mass. The content of the solvent contained in the conductive ink is preferably in the range of 98.0 to 99.98% by mass.

The conductive ink can be printed by a bar coating method, a spin coating method, a spray coating method, a gravure method, a slit coating method, or the like. The shape of the pattern of the transparent conductive pattern film formed by printing is not particularly limited, but the shape of the wiring or electrode pattern formed on the base material, or the film covering the entire surface or a part of the base material. (solid pattern). The formed pattern becomes conductive by heating to dry the solvent.
The dry thickness of the transparent conductive pattern film is preferably 10 to 300 nm, more preferably 30 to 200 nm, although it varies depending on the diameter of the metal nanowires used, the desired sheet resistance value, and the like. If the dry thickness of the transparent conductive film is 10 nm or more, the number of intersections of the metal nanowires increases, so good conductivity can be obtained. If the dry thickness of the transparent conductive film is 300 nm or less, it is possible to obtain good optical properties because light is easily transmitted and reflection by the metal nanowires is suppressed. If necessary, the transparent conductive film may be irradiated with light.
<Protective film>
It is preferable to form a protective film on the transparent conductive pattern film to mechanically protect the transparent conductive pattern film.
In general, the protective film that protects the transparent conductive film is preferably formed from a cured film of a curable resin composition as the protective film from the viewpoint of mechanically protecting the transparent conductive film. However, the cured film is slightly inferior in moldability, and it is preferable to use it as a protective film for three-dimensional molding. As in the present embodiment, when applied to a touch panel, a transparent conductive film laminate having a transparent conductive pattern film is usually used by laminating it to another member. protected form. In that case, the transparent conductive pattern film itself does not require high mechanical strength. Therefore, it is preferable that the main component of the protective film constituting the transparent conductive film laminate of one embodiment is a thermoplastic resin having excellent moldability. In other words, it is preferable that 94% by mass or more of the resin component constituting the protective film is derived from the thermoplastic resin. As will be described later, the protective film can be formed by applying a resin composition in which a resin is dissolved in a solvent onto the transparent conductive pattern film. In this case, it contains a solvent that does not attack the binder resin and the transparent base material of the transparent conductive pattern film and that can be applied well on the transparent conductive pattern film, so that a film can be formed on the transparent conductive pattern film. It is preferred to use a resin composition. Applicable resin compositions include, for example, resin compositions containing ethyl cellulose or polyurethane having carboxy groups. Examples of the resin composition containing ethyl cellulose include Ethocel (registered trademark) STD-100 (ethyl cellulose manufactured by Dow Chemical Company, weight average molecular weight: 180,000, molecular weight distribution (Mw/Mn) = 3.0 [catalog value]). is mentioned. The weight average molecular weight of the polyurethane containing a carboxy group is preferably 1,000 to 100,000, more preferably 3,000 to 85,000, and more preferably 5,000 to 70,000. More preferably, 10,000 to 65,000 is particularly preferable. In the present disclosure, the weight average molecular weight of the carboxyl group-containing polyurethane is a polystyrene-equivalent value measured by GPC. When the weight-average molecular weight of the polyurethane containing a carboxyl group is 1,000 or more, appropriate elongation, flexibility, and strength of the coating film can be obtained. It is highly flexible and does not become too viscous when dissolved, so there are few restrictions on its use.

In the present disclosure, unless otherwise specified, the GPC measurement conditions for the weight-average molecular weight of the carboxy group-containing polyurethane are as follows.
Apparatus name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex (registered trademark) column LF-804
Mobile phase: Tetrahydrofuran Flow rate: 1.0 mL/min
Detector: RI-2031Plus manufactured by JASCO Corporation
Temperature: 40.0°C
Sample volume: sample loop 100 μL
Sample concentration: about 0.1% by mass

The acid value of the polyurethane containing carboxy groups is preferably 10-140 mg-KOH/g, more preferably 15-130 mg-KOH/g. When the acid value of the carboxy group-containing polyurethane is 10 mg-KOH/g or more, the solvent resistance of the protective film is good, and the curability of the resin composition when a small amount of the curing component is used together is also good. When the acid value of the polyurethane containing a carboxyl group is 140 mg-KOH/g or less, the solubility of the polyurethane in a solvent is good, and the viscosity of the resin composition can be easily adjusted to a desired viscosity.

In the present disclosure, the acid value of polyurethane containing carboxy groups is a value measured by the following method.
About 0.2 g of a sample is accurately weighed in a 100 mL Erlenmeyer flask using a precision balance, and 10 mL of a mixed solvent of ethanol/toluene=1/2 (mass ratio) is added and dissolved. Furthermore, 1 to 3 drops of phenolphthalein ethanol solution is added as an indicator to this container, and the sample is sufficiently stirred until it becomes homogeneous. The resulting mixture is titrated with 0.1N potassium hydroxide-ethanol solution, and the end point of neutralization is when the indicator remains slightly red for 30 seconds.

The value obtained using the following formula is taken as the acid value of the polyurethane containing carboxyl groups.
Acid value (mg-KOH/g) = [B x f x 5.611]/S
B: Amount of 0.1N potassium hydroxide-ethanol solution used (mL)
f: Factor S of 0.1N potassium hydroxide-ethanol solution: Amount of sample collected (g)

A polyurethane containing a carboxy group is more specifically a polyurethane synthesized using (a1) a polyisocyanate compound, (a2) a polyol compound, and (a3) a dihydroxy compound having a carboxy group as monomers. From the viewpoint of light resistance and weather resistance, each of (a1), (a2), and (a3) preferably does not contain a conjugated functional group such as an aromatic ring. Each monomer will be described in more detail below.

(a1) Polyisocyanate compound As the (a1) polyisocyanate compound, a diisocyanate having two isocyanato groups per molecule is usually used. Examples of polyisocyanate compounds include aliphatic polyisocyanates and alicyclic polyisocyanates, and these can be used alone or in combination of two or more. A small amount of polyisocyanate having 3 or more isocyanato groups can also be used as long as the carboxy group-containing polyurethane does not gel.

Examples of aliphatic polyisocyanates include 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,9-nonamethylene diisocyanate, 1,10-decamethylene diisocyanate, 2 , 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,2′-diethyl ether diisocyanate, and dimer acid diisocyanate.

Alicyclic polyisocyanates include, for example, 1,4-cyclohexanediisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 3-isocyanatomethyl-3,5 ,5-trimethylcyclohexyl isocyanate (IPDI, isophorone diisocyanate), bis-(4-isocyanatocyclohexyl)methane (hydrogenated MDI), hydrogenated (1,3- or 1,4-)xylylene diisocyanate, and norbornane diisocyanate mentioned.

(a1) By using an alicyclic compound having 6 to 30 carbon atoms other than the carbon atoms in the isocyanato group (-NCO group) as the polyisocyanate compound, the reliability at high temperature and high humidity is high, A protective film suitable for a member of a touch panel having a curved surface area can be obtained. Among the alicyclic polyisocyanates exemplified above, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, bis-(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis (Isocyanatomethyl)cyclohexane is preferred.

As described above, from the viewpoint of weather resistance and light resistance, it is preferable to use a compound that does not have an aromatic ring as the (a1) polyisocyanate compound. Therefore, when an aromatic polyisocyanate or an araliphatic polyisocyanate is used as necessary, the content thereof is preferably 50 mol% or less with respect to the total amount (100 mol%) of the (a1) polyisocyanate compound, It is more preferably 30 mol % or less, still more preferably 10 mol % or less.

(a2) Polyol compound (a2) Polyol compound (however, (a2) polyol compound does not include (a3) a dihydroxy compound having a carboxyl group described later) usually has a number average molecular weight of 250 to 50,000. , preferably 400 to 10,000, more preferably 500 to 5,000. The number average molecular weight of the polyol compound is a polystyrene-equivalent value measured by GPC under the conditions described above.

(a2) Polyol compounds include, for example, polycarbonate polyols, polyether polyols, polyester polyols, polylactone polyols, hydroxyl-terminated polysiloxanes, and C18 (18 carbon atoms) unsaturated fatty acids made from vegetable oils and fats, and A polyol compound having 18 to 72 carbon atoms obtained by hydrogenating a polyvalent carboxylic acid derived from the polymer and converting the carboxylic acid into a hydroxyl group is exemplified. From the viewpoint of the balance between the water resistance of the protective film, the insulation reliability, and the adhesion to the substrate, the (a2) polyol compound is preferably a polycarbonate polyol.

A polycarbonate polyol can be obtained by reacting a diol having 3 to 18 carbon atoms with a carbonate ester or phosgene, and is represented by the following structural formula (1), for example.

In formula (1), R ³ is a residue obtained by removing the hydroxyl group from the corresponding diol (HO--R ³ --OH) and is an alkanediyl group having 3 to 18 carbon atoms, n ₃ is a positive integer, Preferably it is 2-50.

Specifically, the polycarbonate polyol represented by formula (1) is 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1 ,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,10 -Decamethylene glycol or 1,2-tetradecanediol can be used as a starting material.

The polycarbonate polyol may be a polycarbonate polyol (copolymerized polycarbonate polyol) having multiple types of alkanediyl groups in its skeleton. The use of copolymerized polycarbonate polyols is often advantageous from the standpoint of preventing crystallization of polyurethanes containing carboxy groups. Considering solubility in a solvent, it is preferable to use a polycarbonate polyol having a branched skeleton and a hydroxyl group at the end of the branched chain.

A diol having a molecular weight of 300 or less, which is usually used as a diol component when synthesizing polyester or polycarbonate, can also be used as the (a2) polyol compound within a range that does not impair the effects of the present invention. Examples of such low molecular weight diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1 ,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9 -nonanediol, 2-methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 1, 3-cyclohexanedimethanol, diethylene glycol, triethylene glycol, and dipropylene glycol.

(a3) Dihydroxy compound containing a carboxy group (a3) The dihydroxy compound containing a carboxy group has a molecular weight having two selected from hydroxy groups and hydroxyalkyl groups having 1 or 2 carbon atoms A carboxylic acid or aminocarboxylic acid having a is 200 or less is preferable in that the cross-linking point can be controlled. (a3) Dihydroxy compounds containing a carboxy group include, for example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N,N-bishydroxyethylglycine, and N,N-bishydroxyethyl Among these, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid are preferred because of their high solubility in solvents. (a3) The dihydroxy compound containing a carboxy group can be used alone or in combination of two or more.

A polyurethane containing a carboxy group can be synthesized only from the above three components ((a1), (a2) and (a3)). Furthermore, it can be synthesized by reacting (a4) a monohydroxy compound and/or (a5) a monoisocyanate compound. From the viewpoint of light resistance, (a4) monohydroxy compound and (a5) monoisocyanate compound are preferably compounds that do not contain an aromatic ring or a carbon-carbon double bond in the molecule.

Polyurethanes containing carboxyl groups can be prepared by using a suitable organic solvent in the presence or absence of a known urethanization catalyst such as dibutyltin dilaurate, the above-mentioned (a1) polyisocyanate compound, (a2) polyol compound , and (a3) a dihydroxy compound having a carboxy group. It is advantageous to react the carboxy group-containing polyurethane without a catalyst because it is not necessary to consider the contamination of tin or the like in the end.

The organic solvent is not particularly limited as long as it has low reactivity with the isocyanate compound. The organic solvent preferably does not contain a basic functional group such as amine and has a boiling point of 50° C. or higher, preferably 80° C. or higher, more preferably 100° C. or higher. Examples of such solvents include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and dipropylene. Glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone , N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, and dimethylsulfoxide.

Considering that an organic solvent in which the resulting polyurethane has low solubility is not preferable, and that polyurethane is used as a raw material for a protective film in touch panel applications, the organic solvent includes propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Dipropylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, γ-butyrolactone, or combinations thereof are preferred.

The order in which the raw materials are added is not particularly limited, but usually (a2) the polyol compound and (a3) the dihydroxy compound having a carboxyl group are first placed in a reaction vessel, dissolved or dispersed in a solvent, and then heated to 20 to 150°C. , more preferably at 60 to 120°C, (a1) the polyisocyanate compound is added dropwise, and then these are reacted at 30 to 160°C, more preferably 50 to 130°C.

The molar ratio of raw materials charged is adjusted according to the molecular weight and acid value of the desired polyurethane. Specifically, the molar ratio of (a1) the isocyanato group of the polyisocyanate compound to ((a2) the hydroxyl group of the polyol compound + (a3) the hydroxyl group of the dihydroxy compound having a carboxyl group) is preferably 0.5 to 1.5. :1, more preferably 0.8-1.2:1, more preferably 0.95-1.05:1. The molar ratio of (a2) hydroxyl group of the polyol compound to (a3) hydroxyl group of the dihydroxy compound having a carboxyl group is preferably 1:0.1-30, more preferably 1:0.3-10.

As described above, 94% by mass or more of the resin component that constitutes the protective film is preferably derived from a thermoplastic resin. 6 mass % or less of the resin component constituting the protective film may be derived from the curable resin (compound). If the content of the curable resin (compound) of the resin component in the resin composition is in the range of 6% by mass or less, the function as a protective film can be achieved without significantly reducing workability during three-dimensional molding. It is preferable because it can be improved. Suitable curable resins (compounds) that can be used in combination with thermoplastic resins include epoxy resins (compounds) having two or more epoxy groups in one molecule.

When forming the protective film, the thermoplastic resin and the thermosetting resin may react with each other. For example, when a polyurethane containing a carboxy group is used as the thermoplastic resin and an epoxy resin is used as the thermosetting resin, the carboxy group of the polyurethane reacts with the epoxy group of the epoxy resin to form a polyurethane-epoxy resin composite. may be formed. In the present disclosure, "94% by mass or more of the resin component constituting the protective film is derived from a thermoplastic resin" means that the thermoplastic resin used for forming the protective film, such as a polyurethane containing a carboxyl group, is used to form the protective film. means that it corresponds to 94% by mass or more of the resin component of the protective film, and "6% by mass or less of the resin component constituting the protective film is derived from the thermosetting resin" It means that a curable resin such as an epoxy resin accounts for 6% by mass or less of the resin component of the protective film.

Epoxy resins (compounds) having two or more epoxy groups in one molecule include, for example, bisphenol A type epoxy compounds, hydrogenated bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, phenol novolac type Epoxy resins, cresol novolak type epoxy resins, N-glycidyl type epoxy resins, bisphenol A novolak type epoxy resins, chelate type epoxy resins, glyoxal type epoxy resins, amino group-containing epoxy resins, rubber-modified epoxy resins, dicyclopentadiene phenolic type Examples include epoxy resins, silicone-modified epoxy resins, ε-caprolactone-modified epoxy resins, glycidyl group-containing aliphatic epoxy resins, and glycidyl group-containing alicyclic epoxy resins.

An epoxy compound having 3 or more epoxy groups in one molecule can be used more preferably. Examples of such epoxy compounds include EHPE (registered trademark) 3150 (manufactured by Daicel Corporation), jER (registered trademark) 604 (manufactured by Mitsubishi Chemical Corporation), and EPICLON (registered trademark) EXA-4700 (manufactured by DIC Corporation). ), EPICLON® HP-7200 (manufactured by DIC Corporation), pentaerythritol tetraglycidyl ether, pentaerythritol triglycidyl ether, and TEPIC®-S (manufactured by Nissan Chemical Industries, Ltd.).

The blending ratio of the epoxy resin (compound) and the carboxy group-containing polyurethane is the molar ratio (Ep/ COOH) is preferably 0.02 or less.

It is also possible to contain an epoxy compound having only one epoxy group in one molecule. When using an epoxy compound having only one epoxy group in one molecule, it does not form a crosslinked structure by reacting with the carboxy group of the carboxy group-containing polyurethane. You can control the remaining amount. When using an epoxy compound having only one epoxy group in one molecule, the blending ratio of the epoxy resin (compound) and the polyurethane containing the carboxy group is based on the carboxy group (COOH) of the polyurethane containing the carboxy group. The molar ratio (Ep/COOH) of epoxy groups (Ep) in the epoxy resin (compound) is preferably 1.0 or less. When an epoxy resin (compound) having two or more epoxy groups in one molecule and an epoxy resin (compound) having only one epoxy group in one molecule are used together, the carboxy group possessed by the polyurethane containing the carboxy group The ratio (Ep/COOH) of the total moles of epoxy groups (Ep) possessed by both epoxy resins (compounds) to (COOH) is preferably 1.0 or less.

When an epoxy resin (compound) and a polyurethane containing a carboxyl group are used together, a curing accelerator can be further added to the resin composition. Specific examples of curing accelerators include phosphine compounds such as triphenylphosphine and tributylphosphine (manufactured by Hokko Chemical Industry Co., Ltd.), Curesol (registered trademark) (imidazole epoxy resin curing agent: manufactured by Shikoku Kasei Co., Ltd.), 2 -Phenyl-4-methyl-5-hydroxymethylimidazole, U-CAT (registered trademark) SA series (DBU salt: manufactured by San-Apro Co., Ltd.), and Irgacure (registered trademark) 184. The amount of the curing accelerator used is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and still more preferably 40 to 60 parts by mass with respect to 100 parts by mass of the epoxy resin (compound). The curing accelerator is included in the resin component other than the thermoplastic resin.

A curing aid may be used together. Curing aids include, for example, polyfunctional thiol compounds and oxetane compounds. Examples of polyfunctional thiol compounds include pentaerythritol tetrakis(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate). , and Karenz (registered trademark) MT series (manufactured by Showa Denko KK). Examples of the oxetane compound include Aron Oxetane (registered trademark) series (manufactured by Toagosei Co., Ltd.), ETERNACOLL (registered trademark) OXBP and OXMA (both manufactured by Ube Industries, Ltd.). The amount of the curing aid used is preferably 0 per 100 parts by mass of the epoxy resin (compound), since the effect of addition can be obtained and the handling property can be maintained by avoiding an excessive increase in the curing speed. .1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass. The curing aid is also included in the resin component other than the thermoplastic resin.

The resin composition preferably contains 95.0% by mass or more and 99.9% by mass or less of the solvent, more preferably 96% by mass or more and 99.7% by mass or less, and 97% by mass or more and 99.5% by mass or less. More preferably, it contains As the solvent, a solvent that does not attack the transparent conductive pattern film and the transparent base material can be used. The solvent used for synthesizing the carboxy group-containing polyurethane can be used as it is, or other solvents can be used to adjust the solubility or printability of the binder resin. When another solvent is used, the solvent used for synthesizing the carboxy group-containing polyurethane may be distilled off before and after adding the new solvent to replace the solvent. Considering the complexity of the operation and the energy cost, it is preferable to use at least part of the solvent used for synthesizing the carboxy group-containing polyurethane as it is. Considering the stability of the resin composition, the boiling point of the solvent is preferably 80°C to 300°C, more preferably 80°C to 250°C. If the boiling point of the solvent is 80° C. or higher, it can be dried over a certain period of time during printing, and unevenness in the coating film is less likely to occur. If the boiling point of the solvent is 300° C. or lower, the drying and curing do not require heat treatment at a high temperature for a long period of time, and industrial production can be suitably carried out.

Solvents include propylene glycol monomethyl ether acetate (boiling point 146°C), γ-butyrolactone (boiling point 204°C), diethylene glycol monoethyl ether acetate (boiling point 218°C), tripropylene glycol dimethyl ether (boiling point 243°C), etc. Solvents to be used; ether solvents such as propylene glycol dimethyl ether (boiling point 97° C.) and diethylene glycol dimethyl ether (boiling point 162° C.); isopropyl alcohol (boiling point 82° C.), t-butyl alcohol (boiling point 82° C.), 1-hexanol (boiling point 157 ° C.), propylene glycol monomethyl ether (boiling point 120° C.), diethylene glycol monomethyl ether (boiling point 194° C.), diethylene glycol monoethyl ether (boiling point 196° C.), diethylene glycol monobutyl ether (boiling point 230° C.), triethylene glycol (boiling point 276° C.), A solvent containing a hydroxyl group such as ethyl lactate (boiling point 154°C); a ketone solvent such as methyl ethyl ketone (boiling point 80°C); or an ester solvent such as ethyl acetate (boiling point 77°C) can be used. These solvents can be used alone or in combination of two or more. When two or more types are mixed, in addition to the solvent used for synthesizing the polyurethane containing a carboxyl group, the solubility of the polyurethane to be used, the epoxy resin, etc. should be taken into account, and a hydroxy group that does not cause aggregation and precipitation will be or a solvent with a boiling point of 100° C. or less from the viewpoint of the drying property of the ink. Solvents that attack the transparent conductive film or the base material when used alone are preferably used as mixed solvents with other solvents so as to have a composition that does not attack the transparent conductive pattern film or the base material.

The resin composition is a mixture obtained by blending a polyurethane containing a carboxyl group with an epoxy compound, a curing accelerator, and a curing aid as necessary, and the content of the solvent in the resin composition is 95.0 mass. % or more and 99.9% by mass or less, and stirred so that these components become uniform.

Although the solid content concentration in the resin composition varies depending on the desired film thickness and printing method, it is preferably 0.1 to 10% by mass, more preferably 0.5% to 5% by mass. When the solid content concentration is in the range of 0.1 to 10% by mass, the film thickness does not become excessively thick when the resin composition is applied on the transparent conductive film, and the electrical connection with the transparent conductive pattern film is maintained. In addition, the protective film can be provided with weather resistance and light resistance.

Using the resin composition described above, the resin composition is applied on the transparent conductive pattern film by printing such as bar coat printing, gravure printing, inkjet method, slit coating method, etc., and the solvent is dried and removed. A protective film is thus formed. The thickness of the protective film is usually more than 100 nm and 1 μm or less. The thickness of the protective film is preferably more than 100 nm and 500 nm or less, more preferably more than 100 nm and 200 nm or less, still more preferably more than 100 nm and 150 nm or less, and particularly preferably more than 100 nm and 120 nm or less. If the thickness of the protective film is 1 μm or less, it is preferable because electrical continuity between the wiring and the transparent conductive pattern film can be easily obtained in a post-process.

《Touch panel》
A touch panel according to an embodiment of the present disclosure is obtained using a transparent conductive film laminate obtained by sequentially forming a transparent conductive pattern film (for example, a layer containing silver nanowires) and a protective film on a substrate as described above. .
The configuration and manufacturing method of the touch panel will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a schematic diagram showing the layer structure of a display (input/output integrated display device) 12 incorporating a touch panel according to one embodiment. The touch panel built-in display 12 includes a display 13 and a touch panel 11 joined to the display 13 and having a curved area over the entire surface. Although the display 13 is not particularly limited, an OLED (Organic Light Emitting Diode) and a micro LED are exemplified. The display 13 and the touch panel 11 may be joined by, for example, an adhesive tape. Although not shown in the schematic diagram, the touch panel 11 may have a flat portion in addition to the portion having the curved surface area.

The touch panel 11 is connected with the detection circuit 15 . The touch panel 11 includes a cover film 16 and a transparent conductive film laminate 18, as shown in FIG. The transparent conductive film laminate 18 includes a transparent base material 24, a first transparent conductive pattern film 26A and a second transparent conductive pattern film 26B provided on both main surfaces of the transparent base material 24, respectively, and a first transparent conductive pattern film. It has a first protective film 28A covering 26A and a second protective film 28B covering the second transparent conductive pattern film 26B.
The first transparent conductive pattern film 26A has a first transparent conductive pattern, and the second transparent conductive pattern film 26B has a second transparent conductive pattern. In the first transparent conductive pattern film, a first conductive region in which the metal nanowires intersect and are electrically connected, and, for example, a plurality of crossing portions in which the metal nanowires intersect and are electrically connected remain locally. and a first non-conductive region finely divided to a level exhibiting non-conductivity. The first conductive region has an electrode row in which a plurality of electrodes are arranged in a row in the first direction. Similarly, the second transparent conductive pattern film includes a second conductive region in which the metal nanowires intersect and are electrically connected to each other, and for example, a plurality of intersections in which the metal nanowires intersect and electrically connect to each other. and a second non-conductive region which remains substantially but is finely divided to a level exhibiting non-conductivity. The second conductive region has an electrode row in which a plurality of electrodes are connected in a second direction perpendicular to the first direction.

A first transparent conductive pattern film 26A is formed on one main surface of the transparent substrate 24 . A second transparent conductive pattern film 26B is formed on the other main surface of the transparent substrate 24 . Although not shown, the electrode row ends of the first transparent conductive pattern film 26A and the electrode row ends of the second transparent conductive pattern film 26B on the first protective film 28A and the second protective film 28B of the transparent conductive film laminate 18 Electrode pads are provided at positions corresponding to the portions. In addition, lead lines (none of which are shown) are provided so as to be connected to the electrode pads. The electrode pads and lead wires can be integrally formed by applying a conductive paste by screen printing or the like, for example. The lead wire is connected to the proximal end of the terminal (not shown). The tip of the terminal protrudes outward from the outer edge of the transparent base material 24 . Wiring (not shown) is connected to the tip of the terminal. The first transparent conductive pattern film 26A and the second transparent conductive pattern film 26B are electrically connected to the detection circuit 15 (FIG. 1) through wiring. The detection circuit 15 detects the capacitance generated between the electrode pads of the first transparent conductive pattern film 26A and the second transparent conductive pattern film 26B when a finger touches the surface of the touch panel 11, that is, the surface of the cover film 16. It measures finger position by detecting changes in .
The step of forming the transparent conductive film laminate 18 includes a step of forming a solid transparent conductive film on a transparent substrate, a step of forming a protective film, and a step of forming a pattern on the transparent substrate. is preferred.
In the step of forming the transparent conductive film, the first transparent conductive film forming the first transparent conductive pattern film 26A is formed on one main surface of the transparent base material 24, and the second transparent conductive film is formed on the other main surface of the transparent base material 24 to form the first transparent conductive pattern film 26A. 2. A second transparent conductive film is formed as a base for the transparent conductive pattern film 26B. The first transparent conductive film and the second transparent conductive film can be formed by coating conductive ink on the transparent substrate 24 and heating to dry the solvent. The shape of the printed film is preferably a film (solid pattern) covering the entire surface of the transparent substrate 24 . Treatments such as heating and light irradiation are performed during and after drying.

In the step of forming protective films, a first protective film 28A is formed on the first transparent conductive film, and a second protective film 28B is formed on the second transparent conductive film. The method of forming the first protective film 28A and the second protective film 28B is the same as that for the first transparent conductive film and the second transparent conductive film. They are formed by printing, coating, and drying. The first protective film 28A and the second protective film 28B need to be formed after forming the first transparent conductive film and the second protective film 28B after forming the second transparent conductive film, respectively. , there is no necessity of forming after forming the first transparent conductive film and the second transparent conductive film. That is, it is also possible to form in the order of first transparent conductive film→second transparent conductive film→first protective film 28A→second protective film 28B, or first transparent conductive film→first protective film 28A→second transparent film. It is also possible to form the conductive film and then the second protective film 28B in this order.

Next, a pattern forming process is performed. Using a pulsed laser with a pulse width shorter than 1 nanosecond, only the first transparent conductive film is etched from the side of the first protective film 28A to form a first conductive pattern, thereby forming a first transparent conductive pattern film 26A. Eggplant. As described above, when a transparent resin film having a thickness of 40 μm or more is used as the base material, penetration of the pulsed laser beam can be suppressed even with a transparent resin film. Transparent conductive films have characteristic absorption peaks in the optical transmission spectrum due to their constituent nanostructured networks with the intersections of metal nanowires. Therefore, from the first protective film 28A side, the wavelength is within the wavelength region of ±30 nm, the absorption peak maximum wavelength based on the nanostructure network in the light transmission spectrum, and the light transmittance of the resin film is 80% or more. When a pulse laser having a width shorter than 1 nanosecond is applied to the first transparent conductive film, the second transparent conductive film formed on the back side of the substrate is not etched, and only the first transparent conductive film is selectively etched. can do. Since the nanostructure network having the intersections of metal nanowires has an absorption peak due to this in the light transmission spectrum, it can be detected by a pulsed laser with a wavelength close to this absorption peak maximum wavelength (within the absorption peak maximum wavelength ± 30 nm). Can be etched. After selective etching of the first transparent conductive film from the first protective film 28A side, selective etching of the second transparent conductive film from the second protective film 28B side is similarly possible. That is, the second conductive region and the second conductive region different from the first transparent conductive pattern film 26A having the first conductive region and the first non-conductive region formed in the first transparent conductive film with respect to the second transparent conductive film 26A. A second transparent conductive pattern film 26B having two non-conductive regions can be formed. The pulse width of the pulsed laser is preferably less than 0.1 (100 picoseconds) nanoseconds, more preferably less than 0.01 nanoseconds (10 picoseconds), 0.001 nanoseconds (1 picosecond) ), i.e. femtosecond pulsed lasers are more preferably used.

When the transparent conductive film is etched by the pulse laser, the metal forming the nanostructure network having the intersections of the metal nanowires, which is present in the area irradiated with the pulse laser and which constitutes the transparent conductive film, melts. As a result, it becomes impossible to maintain a sufficient network structure to exhibit conductivity, resulting in a non-conductive region. The wire-like metal that formed the nanostructured network is broken and the non-conductive regions contain fragments of the nanostructured network. The fragments include those of various shapes, for example, nanowires cut into granules (spherical, elliptical, columnar, etc.), and local network structures (including intersections of metal nanowires). The remaining non-conductive regions as a whole include those that are finely divided to the level of non-conductivity (intersections of metal nanowires (cross-shaped fragments), etc.).

When patterning is performed by laser light, the network structure contained in the irradiated area of the transparent conductive film cannot be maintained sufficiently to exhibit conductivity, and the area becomes non-conductive, eliminating the need to use chemicals. Therefore, no waste liquid is generated, and it is easy to deal with small lots and arbitrary shapes. Preferred wavelengths for lasers are between 250 nm and 1400 nm. When metal nanowires are used as the conductive fibers, the wavelength is more preferably 250 nm to 450 nm, which is the absorption wavelength of the short diameter (diameter of the metal nanowires). In particular, it is preferable from the viewpoint that excessive heating can be suppressed when forming a pattern with a pulse laser.
The shape of the pattern to be formed is arbitrary and can be selected from known ones. A plurality of electrode rows are formed on each of the first transparent conductive film and the second transparent conductive film for use as a position recognition sensor of a touch panel. As a result, the transparent conductive film becomes a transparent conductive pattern film (first transparent conductive pattern film 26A, second transparent conductive pattern film 26B) having conductive regions including a plurality of electrode rows and non-conductive regions. The aperture ratio of the transparent conductive pattern film is 40% or more and 70% or less, preferably 45% or more and 69% or less, and more preferably 45% or more and 68% or less. If the aperture ratio of the transparent conductive pattern film exceeds 70%, the sheet resistance of the transparent conductive film becomes too large, and the sensitivity as a touch panel becomes low, which is not preferable. From this viewpoint, the transparent conductive film constituting the transparent conductive film laminate 18 preferably has a low sheet resistance, preferably 1 Ω/□ or more and 300 Ω/□ or less, more preferably 15 Ω/□ or more and 200 Ω/□ or less, and further. 20Ω/□ or more and 100Ω/□ or less is preferable. If the aperture ratio of the transparent conductive pattern film is less than 40%, the optical properties deteriorate, so it is not suitable as a transparent conductive film laminate. It is preferable to use a transparent conductive film having an aperture ratio of 40% or more and 70% or less before pattern formation from the viewpoint of easy pattern processing so that the aperture ratio is 40% or more and 70% or less after pattern formation. A transparent conductive film having an aperture ratio of less than 40% can also be patterned so that the aperture ratio of the transparent conductive pattern film after pattern formation is 40% or more and 70% or less. In order to suppress visible bones, it is preferable to set the aperture ratio of the conductive region constituting the transparent conductive pattern film to 40% or more and 70% or less.
In addition, this aperture ratio is occupied by the conductive fibers (when the conductive fibers are metal nanowires, the metal nanowires and the nanostructure network fragments constituting the nanostructure network) in a plan view of the transparent conductive pattern film. It is the area ratio (%) of the area without the shavings, and is calculated by observing with a shape measuring laser microscope as described later.

《Leader wire connection method》
An embodiment of a method for connecting lead wires from electrode rows of a transparent conductive pattern film formed on a substrate will be described with reference to FIG. In order to simplify the explanation, FIG. 3 shows the transparent conductive pattern film 1 having the electrode array (the shape of the unit electrode is omitted) 2 as a plan view of the transparent conductive film laminate.
As shown in FIG. 3(a), a lead wire 3 is formed at one end of the electrode row 2 for connection by screen printing of silver paste or the like. Next, as shown in FIG. 3(b), unnecessary portions of the transparent conductive pattern film 1 on the top, bottom and left sides of the figure are cut. Further, a flexible printed circuit board 3' is connected to the tip of the lead wire 3 as shown in FIG. 3(c). Finally, as shown in FIG. 3(d), the unnecessary portion on the right side of the transparent conductive pattern film 1 is cut to obtain a shape that can be used for manufacturing a touch panel.
A first transparent conductive pattern film 1 having electrode rows 2 and lead wires 3 formed on the surface is located on the back surface via a substrate, and a second transparent conductive pattern film similarly having electrode rows and lead wires formed on the surface. Together with the plane of the pattern film, it is molded into a curved surface to obtain a touch panel.

As another embodiment of the transparent conductive film laminate, a first transparent conductive film laminate 18A and a second transparent conductive film laminate 18B can be provided. In the embodiment of the transparent conductive film laminate shown in FIG. 2, the transparent conductive film laminate 18 provided with the transparent

conductive pattern films

26A and 26B on both main surfaces of the transparent base material 24 has been described. is not limited to this. For example, description will be made with reference to FIG. 4 in which the same components as those in FIG. 2 are denoted by the same reference numerals. A touch panel 41 shown in FIG. 4 includes a first transparent conductive film laminate 18A and a second transparent conductive film laminate 18B. 18 A of 1st transparent conductive film laminated bodies have 24 A of 1st transparent base materials, 26 A of 1st transparent conductive pattern films, and 28 A of 1st protective films in order. The second transparent conductive film laminate 18B has a second transparent substrate 24B, a second transparent conductive pattern film 26B, and a second protective film 28B in this order. The first transparent conductive film laminate 18A and the second transparent conductive film laminate 18B are integrated by bonding the first transparent substrate 24A and the second protective film 28B via an adhesive layer 30, which will be described later. there is In this embodiment, two transparent conductive film laminates having a transparent conductive pattern film only on one main surface of a transparent substrate are used. Since two film laminates are used, there is no risk that the pulsed laser beam for processing the transparent conductive film on one main surface will penetrate the transparent substrate and damage the other transparent conductive film. Therefore, a transparent resin film having a thickness of less than 40 μm, preferably 10 μm or more can also be applied to the touch panel of the present embodiment.
Also, the first and second transparent conductive films can be similarly formed on the first transparent substrate 24A and the second transparent substrate 24B by the method described above. Similarly, the electrode arrays, lead wires, and the like can be formed by commonly known methods, and specifically, the methods described above can be used.

《Display with built-in touch panel》
In the case of the touch panel layer configuration example shown in FIG. 2, in order to obtain the touch panel built-in display (also referred to as an input/output integrated display device) shown in FIG. After bonding to obtain the touch panel 11, the touch panel 11 and the display 13 are bonded to obtain the touch panel built-in display 12.例文帳に追加The touch panel 11 is obtained by bonding the first protective film 28A and the cover film 16 via the adhesive layer 30 . Next, the touch panel 11 is integrated with the display 13 by bonding the second protective film 28B and the display 13 together. As described above, a touch panel built-in display including the touch panel 11 is formed. In FIG. 1 , the touch panel 11 and the display 13 are illustrated as if they are joined from a shape having a curved surface. After molding, the display 13 may be bonded. In the latter case, display 13 may be planar. In the case of the touch panel layer configuration example shown in FIG. After the second transparent substrate 24B of the touch panel 41 and the display 13 are joined together, a touch panel built-in display can be obtained. The order of bonding and integration via the adhesive layer 30 does not matter. The three-dimensional molding may be performed after the touch panel 41 and the display 13 are bonded together, or the display 13 may be bonded after the touch panel 41 is molded to have a curved surface. In the latter case, display 13 may be planar.
As the adhesive layer 30, a layer capable of adhering layers facing up and down is used. For example, a film having optical transparency and adhesiveness such as OCA (Optical Clear Adhesive) that can be adhered, or a liquid curable adhesive layer composition containing a polymerizable compound such as OCR (Optical Clear Resin) is formed. and a light transmissive film. If the display 13 has a planar shape, it is preferable to use OCR. The film thickness of the adhesive layer is preferably 10 μm to 150 μm.

The cover film 16 is provided to protect the touch panel including the electrodes and the like. The cover film 16 is not particularly limited as long as it can be molded into a shape having a curved surface area and can maintain the visibility of images, characters, etc. on the display. For example, resin films such as polycarbonate, polyester (polyethylene terephthalate [PET], polyethylene naphthalate [PEN], etc.), and acrylic resins (polymethyl methacrylate [PMMA], etc.) can be used. Furthermore, it is possible to provide a protective layer such as a hard coat layer on the upper side (observer side) of these resin films to improve strength, and to perform surface treatment to improve chemical resistance. Surface treatment may be performed after subsequent molding.

《Three-dimensional molding》
A transparent conductive film laminate obtained by sequentially forming a transparent conductive pattern film (for example, a layer containing silver nanowires) and a protective film on a substrate has excellent three-dimensional formability. Examples of the three-dimensional molding method for the transparent conductive film laminate include various known methods such as vacuum molding, blow molding, free blow molding, air pressure molding, vacuum pressure molding, and heat press molding. In particular, heat forming, such as hot press and vacuum pressure forming, is preferred.
Regardless of which method is used, stress is applied to the three-dimensionally processed transparent conductive film laminate and distortion occurs. The transparent conductive film laminate is stretched along with this strain. In a transparent conductive film laminate with low three-dimensional moldability, breakage of the transparent conductive pattern film constituting the transparent conductive film laminate or significant increase in sheet resistance is usually observed at low stress (low draw ratio). On the other hand, in a transparent conductive film laminate with good three-dimensional moldability, the transparent conductive pattern film does not break even under high stress (high draw ratio), or the increase in sheet resistance is small. Therefore, the three-dimensional moldability of the transparent conductive film laminate can be evaluated by performing a tensile test on the transparent conductive film laminate and measuring the change in the sheet resistance value. By using a protective film in which 94% by mass or more of the resin component is a thermoplastic resin, cracks are less likely to occur in the protective film even when strain is applied, and cracks in the protective film propagate to the transparent conductive pattern film to reduce its conductivity. It is thought that this is because it is possible to avoid impairing the quality. From the viewpoint of three-dimensional moldability, the protective film preferably does not contain a curing component (epoxy compound, curing accelerator, etc.).

Since the touch panel 11 of the present disclosure is provided with the transparent conductive film laminate 18, it is excellent in three-dimensional workability, so by providing it in a display having a curved surface area, the touch panel built-in display 12 having a curved surface can be formed. Even if the display 13 is flat, the display 12 with a built-in touch panel having a curved surface can be formed by providing the touch panel 11 having a curved surface. In the touch panel built-in display 12, the display of the display 13 is transmitted through the touch panel 11 when the display 13 is lit. Therefore, the user can visually recognize the display of the display 13 from the main surface of the touch panel 11 opposite to the main surface to which the display 13 is joined. When the user touches the main surface of the cover film 16, which is the surface of the display with built-in touch panel 12, with a finger, the detection circuit 15 measures the position of the finger. Thus, the user can perform desired operations through the touch panel 11 . The same applies to the touch panel 41 of the present disclosure.

Since the touch panel of this embodiment has a curved area, it is possible to match it with the shape of the touch panel when the shape of the place where the touch panel is applied is not flat. It is also possible to improve the visibility of

Although the touch panel 11 shown in FIG. 1 has a cylindrical shape with a concave cylindrical surface, the present invention is not limited to this. For example, as shown in FIG. 5, which is a modified example, the touch panel 32 may have a semi-cylindrical shape having a convex cylindrical surface. The touch panel 32 has a convex cylindrical surface 33 and can be operated by a user touching the cylindrical surface 33 . As shown in another variation, FIG. 6, the touch panel 34 may be dome-shaped. The touch panel 34 has a convex spherical surface 35 and can be operated by the user touching the spherical surface 35 .

<<Application example>>
By arranging the obtained touch panel on at least a part of various displays, an input/output integrated display device can be obtained. Examples of displays include organic EL, liquid crystal displays, and rear projection devices.
Applications of the touch panel of the present embodiment include an in-vehicle display. Specifically, it can be used in car center consoles, including car navigation systems, audio equipment, and room temperature control panels. In addition, bank ATMs, ticket vending machines, reception desks at financial institutions, search-type tourist information equipment for public facilities, etc.: Factory equipment operation units: PCs, multi-function devices, etc. IT equipment input parts: Store POS systems: Various medical equipment display, display at amusement facilities, and the like.

The present invention is not limited to the above embodiments, and other embodiments are possible within the spirit of the present invention.
For example, in the above embodiments, the patterning of the electrodes is performed after applying the conductive ink and making it conductive, but it is also possible to perform the patterning when the conductive ink is printed.
Further, although FIG. 3 mainly shows an example in which electrode rows are provided on almost the entire surface of the touch panel, and almost the entire surface serves as an input area, the following form is also possible.
1) An input area is provided at one or more specific locations on a curved surface area. If there are multiple input areas, each input area may have a different shape.
2) Providing locations with different curvatures in one input area, or having multiple input areas with different curvatures. In this case, it is possible to improve the visibility of the boundary of the input area by changing the curvature.
3) For molding into a curved surface, the entire touch panel must be raised except for the edges.
4) Forming a curved surface area only at a specific portion as an input area.
5) Provide an input area in a place other than the curved surface area.

FIG. 7 shows a schematic diagram of an example of a touch panel portion when the touch panel is applied to the center console of an automobile and is used as an input/output integrated type display device that satisfies the above 1) and 2). In this example, the touch panel 36 has two input areas with different shapes, a first input area 37 having a substantially rectangular parallelepiped shape and a second input area 38 having a substantially truncated cone shape, on the curved surface area 39. It is integrally molded to match the shape of the console. The first input area 37 has, for example, a substantially rectangular parallelepiped shape of 7 cm long, 5 cm wide, and 1 cm high, and is provided in front of the center console. It has a truncated cone shape with a bottom diameter of about 3 cm, a top diameter of about 2 cm, and a height of about 1 cm, and is installed near the driver's seat on the center console.
In the first input area 37, as an initial screen, icons indicating systems such as car navigation, air conditioning, lighting, telephone, and audio equipment are displayed (not shown). It is designed so that each system can be operated by touching it. Further, the second input area 38 allows the user to switch between the systems displayed in the first input area 37 and the second input area 38 by touching the second input area 38 one or more times, and , By swiping and touching the second input area 38, the numbers (temperature, distance, etc.) displayed on the system in the first input area 37 and the second input area 38 are changed according to the swiped distance. designed to be able to
As described above, the first input area 37 is provided in front of the center console, and it is difficult for the driver to operate while viewing the icons displayed in the first input area 37 while driving. On the other hand, since the second input area 38 exists near the driver's seat, the driver can operate the second input area 38 without visually recognizing his hand while driving. Operation of the system substantially displayed in the first input area 37 becomes possible.
It is also preferable to provide one or a plurality of third input areas (not shown) dedicated to a single system such as illumination in places other than the first input area 37 and the second input area 38 on the touch panel 36 .

The embodiments of the present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited to these examples.

<Production of silver nanowires>
Polyvinylpyrrolidone K-90 (manufactured by Nippon Shokubai Co., Ltd., 0.98 g), AgNO ₃ (1.04 g) and FeCl ₃ (0.8 mg) were dissolved in ethylene glycol (250 mL) and heated at 150° C. for 1 hour. reacted with The obtained silver nanowire coarse dispersion is dispersed in 2000 mL of a mixed solvent of water / ethanol = 20/80 [mass ratio], and a desktop small tester (manufactured by NGK INSULATORS, LTD., using a ceramic membrane filter Sefilt, membrane area 0.24 m ² , pore diameter 2.0 μm, size Φ 30 mm × 250 mm, filtration differential pressure 0.01 MPa), circulation flow rate 12 L / min, dispersion temperature 25 ° C. Remove impurities by performing cross flow filtration, and silver nanowires. Obtained.
The silver nanowires had an average diameter of 26 nm and an average major axis length of 20 μm. The average diameter of the silver nanowires is obtained by measuring the dimension (diameter) of 100 arbitrarily selected silver nanowires using a field emission scanning electron microscope JSM-7000F (manufactured by JEOL Ltd.). Calculated as an arithmetic mean. The average length of the long axis of the silver nanowires was obtained by measuring the dimension (length) of 100 arbitrarily selected silver nanowires using a shape measuring laser microscope VK-X200 (manufactured by Keyence Corporation). It was obtained as an arithmetic mean value of the measured values.
Reagents manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. were used as ethanol, ethylene glycol, AgNO ₃ and FeCl ₃ .

<Preparation of conductive ink (silver nanowire ink)>
Preparation Example 1 (silver nanowire ink 1)
11 g of a water/ethanol mixed solvent dispersion of silver nanowires synthesized by the polyol method (silver nanowire concentration 1.30% by mass, water/ethanol = 20/80 [mass ratio]), 1.1 g of water, 6.0 g of methanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 7.2 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 12.8 g of propylene glycol monomethyl ether (PGME, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), propylene glycol1. 2 g (PG, manufactured by Asahi Glass Co., Ltd.), poly-N-vinylacetamide (PNVA (registered trademark)) aqueous solution (manufactured by Showa Denko Co., Ltd., grade: GE191-103, solid content concentration 10% by mass, absolute molecular weight 900,000) 0 0.65 g was mixed and stirred for 1 hour at room temperature in an air atmosphere (rotation speed 100 rpm) with a mix rotor VMR-5R (manufactured by AS ONE Corporation) to prepare 40.0 g of silver nanowire ink 1.

Preparation Example 2 (silver nanowire ink 2)
As 11 g of the water/ethanol mixed solvent dispersion of the silver nanowires synthesized by the polyol method, Preparation Example 1 was used except that the silver nanowire concentration was 0.60% by mass and water/ethanol = 20/80 [mass ratio]. 40.0 g of silver nanowire ink 2 was prepared in the same manner as.

Preparation Example 3 (silver nanowire ink 3)
11 g of a water/ethanol mixed solvent dispersion of silver nanowires synthesized by the above polyol method (silver nanowire concentration 0.60% by mass, water/ethanol = 20/80 [mass ratio]), 1.75 g of water, 6.0 g of methanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 6.55 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 12.8 g of propylene glycol monomethyl ether (PGME, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), propylene glycol1. 2 g (PG, manufactured by Asahi Glass Co., Ltd.), Ethocel (registered trademark) STD 100 cps (ethyl cellulose manufactured by Dow Chemical (US)) solution (10% by mass solid concentration ethanol solution) 0.65 g were mixed, and mixed with a mix rotor VMR-5R ( manufactured by AS ONE Co., Ltd.) for 1 hour at room temperature in an air atmosphere (rotational speed: 100 rpm) to prepare 40.0 g of silver nanowire ink 3.

Preparation Example 4 (silver nanowire ink 4)
11 g of a water/ethanol mixed solvent dispersion of silver nanowires synthesized by the polyol method (silver nanowire concentration 0.15% by mass, water/ethanol = 20/80 [mass ratio]), 1.1 g of water, and 6.0 g of methanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 7.2 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 12.8 g of propylene glycol monomethyl ether (PGME, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), propylene glycol1. 2 g (PG, manufactured by Asahi Glass Co., Ltd.), PNVA (registered trademark) aqueous solution (manufactured by Showa Denko Co., Ltd., grade: GE191-103, solid content concentration 10% by mass, absolute molecular weight 900,000) 0.65 g is mixed and mixed with a mix rotor. 40.0 g of silver nanowire ink 4 was prepared by stirring with VMR-5R (manufactured by AS ONE Corporation) for 1 hour at room temperature in an air atmosphere (rotational speed: 100 rpm).

<Printing of silver nanowire ink coating>
Using the silver nanowire ink 1 prepared in Preparation Example 1 above, a polycarbonate (PC) film (Iupilon (registered trademark) FS-2000H manufactured by Mitsubishi Gas Chemical Company, Inc.) was printed with a bar coater (AFA-Standard manufactured by Kotec Co., Ltd.). , glass transition temperature: 130 ° C. (catalog value), 100 μm thickness) on the main surface, coated with a wet film thickness of 20 μm, and a transparent conductive film (silver nanowire ink coating film) was printed as an A4 size solid pattern. .
Using a thermostat ETAC HS350 manufactured by Kusumoto Kasei Co., Ltd., the solvent was dried at 80° C. for 1 minute, and then the sheet resistance of the obtained transparent conductive film was measured. The sheet resistance was obtained by dividing the transparent conductive film (solid pattern) into areas of 3 cm square, and measuring the vicinity of the center of each area using a non-contact resistance measuring device (EC-80P manufactured by Napson Co., Ltd.). Arithmetic mean value of sheet resistance. The sheet resistance of the transparent conductive film using the silver nanowire ink 1 was 20Ω/□.
The thickness of the transparent conductive film was measured using a film thickness measurement system F20-UV (manufactured by Filmetrics Co., Ltd.) based on light interferometry, and found to be 80 nm. For the thickness of the transparent conductive film, a spectrum from 450 nm to 800 nm was used for analysis, and the average value obtained by measuring three points at different measurement points was used. According to this measurement system, it is possible to directly measure the film thickness (Tc) of the silver nanowire layer formed on the transparent substrate.

<Production of protective film ink (resin composition)>
Synthesis Example of Polyurethane Containing Carboxy Group Synthesis Example 1
A 2 L three-necked flask equipped with a stirrer, a thermometer, and a condenser (reflux condenser) was charged with C-1015N (manufactured by Kuraray Co., Ltd., polycarbonate diol, raw material diol molar ratio: 1,9-nonanediol: 2) as a polyol compound. -Methyl-1,8-octanediol = 15:85, molecular weight 964) 16.7 g, 2,2-dimethylolbutanoic acid (manufactured by Huzhou Changsheng Chemical Co., Ltd.) as a dihydroxy compound containing a carboxy group 10.8 g , and 62.6 g of propylene glycol monomethyl ether acetate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) as a solvent were charged, and the 2,2-dimethylolbutanoic acid was dissolved at 90°C.
The temperature of the reaction solution is lowered to 70° C., and 23.5 g of Desmodur (registered trademark)-W (bis-(4-isocyanatocyclohexyl)methane, manufactured by Sumika Covestro Urethane Co., Ltd.) is added as a polyisocyanate using a dropping funnel. was added dropwise over 30 minutes. After completion of the dropwise addition, the temperature was raised to 100°C and the reaction was carried out at 100°C for 15 hours. After confirming by IR that the isocyanate had almost disappeared, 0.5 g of isobutanol was added and the reaction was further carried out at 100°C for 6 hours. gone. The weight-average molecular weight of the resulting polyurethane containing carboxyl groups determined by GPC was 33,500, and the acid value of the resin solution was 39.4 mg-KOH/g.

Protective film ink 1
A mixture of 1-hexanol (COH) and ethyl acetate (EA) (COH:EA) was added as a solvent to 7.1 g of the polyurethane solution containing a carboxyl group obtained in Synthesis Example 1 (solid concentration: 42.4% by mass). = 50:50 (mass ratio)) 92.9 g, and stirred at 1200 rpm for 20 minutes using a spin/revolution vacuum mixer Awatori Mixer (registered trademark) ARV-310 manufactured by Thinky Co., Ltd. Then, protective film ink 1 was obtained. The nonvolatile content (solid content) concentration (the amount of polyurethane containing a carboxyl group) of protective film ink 1 calculated from the mass before and after solvent drying was 3% by mass.

Protective film ink 2
0.002 g of pentaerythritol tetraglycidyl ether (manufactured by Showa Denko KK) as epoxy compound 1 was added to 1.8 g of the polyurethane solution containing a carboxyl group obtained in Synthesis Example 1 (solid content concentration: 42.4% by mass). U-CAT5003 (quaternary phosphonium bromide, manufactured by San-Apro Co., Ltd.) 0.05 g as a curing accelerator, a mixture of 1-hexanol (COH) and ethyl acetate (EA) as a solvent (COH: EA = 50: 50 (mass ratio )) is added, and the mixture is stirred for 20 minutes at 1200 rpm using a rotation/revolution vacuum mixer, Thinky Co., Ltd. (registered trademark) ARV-310, and the protective film ink 2 is added. Obtained.
The nonvolatile content (solid content) concentration (the total amount of polyurethane containing a carboxyl group, epoxy compound, and curing accelerator) of protective film ink 2 calculated from the mass before and after solvent drying was 3% by mass. The molar ratio (Ep/COOH) of the epoxy group (Ep) of the epoxy resin to the carboxy group (COOH) of the carboxy group-containing polyurethane in the protective film ink 2 is 0.02.

Protective film ink 3
In the protective film ink 1, the polyurethane solution containing a carboxyl group was changed to 30.0 g of Ethocel (registered trademark) STD 100 cps (ethyl cellulose manufactured by Dow Chemical (US)) solution (ethanol solution with a solid concentration of 10% by mass), Protective film ink 1 was prepared in the same manner as protective film ink 1, except that 70.0 g of a mixture of 1-hexanol (C6OH) and ethyl acetate (EA) (C6OH: EA = 50:50 (mass ratio)) was added as a solvent. got 3. The nonvolatile content (solid content) concentration (the amount of Ethocel (registered trademark)) of the protective film ink 3 calculated from the mass before and after drying the solvent was 3% by mass.

<Printing of protective film>
Example 1
Using the silver nanowire ink 1 obtained in the above preparation example 1, on the main surface of the transparent conductive film (silver nanowire ink coating film) printed on the main surface of the PC film, using the above-mentioned bar coater , the protective film ink 1 was applied to a wet film thickness of about 7 μm, and a transparent conductive film with a protective film (silver nanowire ink coating film with a protective film) was printed as a solid pattern of A4 size. Solvent drying was carried out at 80° C. for 1 minute using the aforementioned constant temperature vessel, and the transparent conductive film laminate of Example 1 was obtained.
The sheet resistance of the obtained transparent conductive film laminate was measured. In this case, the sheet resistance was obtained by dividing the transparent conductive film laminate (solid pattern) into areas of 3 cm square and measuring the vicinity of the center of each area using the non-contact resistance measuring instrument described above. is the arithmetic mean of The sheet resistance of the transparent conductive film laminate using protective film ink 1 was 20Ω/□.
The thickness of the protective film was 90 nm as a result of measurement using a film thickness measurement system F20-UV (manufactured by Filmetrics Co., Ltd.) based on the optical interferometry as in the case of the thickness of the silver nanowire layer described above. In this case, the spectrum from 450 nm to 800 nm was used for the analysis, and the measurement points were changed, and the average value of three measurements was taken as the film thickness. According to this measurement system, the total film thickness (Tc+Tp) of the film thickness (Tc) of the silver nanowire layer formed on the transparent substrate and the film thickness (Tp) of the protective film formed thereon can be directly measured. Therefore, the film thickness (Tp) of the protective film is obtained by subtracting the previously measured film thickness (Tc) of the silver nanowire layer from this measured value.

Examples 2-5 and Comparative Example 1
In the same manner as in Example 1, silver nanowire ink coating films and protective films were formed in the combinations shown in Table 1 below to obtain transparent conductive film laminates of Examples 2 to 5 and Comparative Example 1.

Comparative example 2
A photosensitive dry film (manufactured by Asahi Kasei Corporation, trade name “Sunfort”) was laminated on a polyethylene terephthalate (PET) substrate with a copper foil. Exposure, development, and rinsing were performed through a photomask to provide patterning. After that, the copper in the portion where the dry film was removed was etched with a copper etchant, and the remaining dry film portion was removed with an organic solvent remover. A two-layer (PET/copper metal mesh) configuration in which only a 5 mm-wide electrode row (space 50 μm) made of copper metal mesh with a line width of 5 μm and a pitch interval of 120 μm is provided on the PET substrate, and no protective film is formed. got a sheet.

<Electrode array fabrication by laser etching>
A femtosecond pulse laser with a wavelength of 355 nm (pulse width of 500 fs, frequency of 1000 kHz, processing speed of 5000 mm/s, output of 0.2 W) was used to pattern from the protective layer side of the transparent conductive film laminates produced in Examples 1 to 5 and Comparative Example 1. Processing was performed to form an X-axis transparent conductive pattern film provided with an X-axis electrode row (5 mm width, 50 μm space) for detecting changes in capacitance in the X-axis direction. Subsequently, another transparent conductive film laminate prepared in Examples 1 to 5 and Comparative Example 1 was prepared, and from the protective film side, under the same conditions as above, the change in capacitance in the Y-axis direction was detected. A transparent conductive pattern film for the Y-axis was formed, provided with an axis electrode row (total width of 5 mm of 1 mm width and dummy pattern width of 4 mm, space 50 μm).
Thus, two kinds of patterned transparent conductive film laminates corresponding to the X-axis electrode and the Y-axis electrode were obtained.

<Production of Wiring by Silver Paste Printing>
Silver paste (Toyobo Co., Ltd.) was applied to the protective layer of the two patterned transparent conductive film laminates (X-axis electrode and Y-axis electrode) obtained above and to the copper metal mesh laminate obtained in Comparative Example 2. DW-520H (manufactured by the same company) was applied by a screen printer and heat-treated at 80° C. for 30 minutes to form wiring electrodes, thereby obtaining a transparent conductive film with a silver wiring-embedded pattern. Since the protective film is thin and some of the silver nanowires that make up the transparent conductive film are exposed on the protective film, the silver wiring pattern and the transparent conductive film provided on the protective film are processed with silver paste. The obtained X-axis electrode and Y-axis electrode were electrically connected, and a transparent conductive film laminate with a pattern including silver wiring was obtained for each of the X-axis electrode and the Y-axis electrode.

<Bonding of Flexible Printed Wiring Board and Transparent Conductive Film Laminate>
The silver wiring portion of the transparent conductive film laminate with a pattern including silver wiring obtained above (X-axis electrode, Y-axis electrode) and the flexible printed wiring board (YFC0-SHW-CN80P-200mm, YFC0-SHW manufactured by Yamashita Materials Co., Ltd.) -CN56P-200 mm) were pressure-bonded using an anisotropic conductive film (MF-347SHP manufactured by Showa Denko Materials Co., Ltd., 2 mm width).
(crimping conditions)
Pressure: 3.0MPa
Crimp temperature: 130°C
Crimping time: 13 seconds

<Lamination using optical double-sided pressure-sensitive adhesive sheet>
Using an optical double-sided pressure-sensitive adhesive sheet, a laminate of a transparent conductive film laminate (X-axis electrode), a transparent conductive film laminate (Y-axis electrode), and a cover film was produced.
First, the transparent conductive film laminate (X-axis electrode) and the transparent conductive film laminate (Y-axis electrode) obtained above were laminated to obtain a transparent conductive film laminate (XY-axis electrode). Specifically, a sheet piece is cut out from a double-sided adhesive sheet (manufactured by Sekisui Chemical Co., Ltd., HSV100, 100 μm thick), one separator is peeled off, and the exposed adhesive surface is used as a transparent conductive film laminate (Y-axis electrode ) using a hand roller (2 kg roller) under the condition of one reciprocation. Next, the other separator is peeled off, and the exposed adhesive surface is attached to the PC film surface of the transparent conductive film laminate (X-axis electrode) under the following conditions to form an X-axis sensor substrate/double-sided adhesive sheet/Y-axis sensor. A transparent conductive film laminate (XY axis electrodes) having the structure of the substrate was produced.
Next, a sheet piece is cut out from another double-sided adhesive sheet (manufactured by Sekisui Chemical Co., Ltd., HSV100, 100 μm thick), one separator is peeled off, and the exposed adhesive surface is used as a Y-axis sensor substrate (transparent conductive film laminated A hand roller (2 kg roller) was applied to the surface of the protective layer of the body (Y-axis electrode) under the condition of one reciprocation. Next, peel off the other separator and attach the other exposed adhesive surface to the surface of the cover film (polycarbonate film: Iupilon (registered trademark) FS-2000H manufactured by Mitsubishi Gas Chemical Co., Ltd., 100 μm thick) under the following conditions. A projection touch panel test piece having a configuration of A4 size X-axis sensor substrate/double-sided adhesive sheet/Y-axis sensor substrate/double-sided adhesive sheet/cover film was produced.
(Lamination conditions)
Surface pressure: 0.4 MPa
Degree of vacuum: 30 Pa
Affixing time: 2 seconds Next, the test piece was placed in an autoclave and autoclaved for 15 minutes under conditions of a temperature of 50°C and a pressure of 0.5 MPa.
No moire pattern was visually observed on any of the touch panel test pieces of Examples 1 to 5 and Comparative Example 1.

<Three-dimensional molding>
A press machine was used for the three-dimensional molding. After pre-drying the test piece at 100° C. for 2 minutes, it was inserted into a press set at 125° C. for a hemispherical upper die and 110° C. for a lower die having a radius of curvature of 100 mm. Then, it was pressed with a mold, and the mold clamping pressure was maintained at 2 tons for 3 minutes.
It was confirmed that the X-axis sensor substrate/double-sided pressure-sensitive adhesive sheet/Y-axis sensor substrate/double-sided pressure-sensitive adhesive sheet/cover film projection type touch panel of Examples 1 to 5 all operated in a three-dimensionally molded state. On the other hand, in the test using the transparent conductive film laminate of Comparative Example 1, the touch panel was not driven after the three-dimensional molding.
Further, a touch panel was produced by using an optical double-sided pressure-sensitive adhesive sheet and a cover film in the same manner as in Example 1 for the two-layer (PET/copper metal mesh) sheet of Comparative Example 2, and three-dimensional molding was performed. However, the touch panel was not driven after three-dimensional molding. In addition, in Comparative Example 2, a moiré pattern was observed when visually observed before the three-dimensional molding.

Evaluation of Transparent Conductive Film Each transparent conductive film laminate was evaluated as follows. Table 1 shows the results.
<Sheet resistance value>
Each obtained in each of the above examples and comparative examples using a non-contact resistance measuring device (EC-80P manufactured by Napson Co., Ltd., probe type High: 10 to 1000 Ω / □, S-High: 1000 to 3000 Ω / □) A sheet resistance value of the transparent conductive film laminate was measured.

<Aperture ratio>
Using a shape measuring laser microscope VK-X200 (manufactured by KEYENCE CORPORATION), the surface of each transparent conductive film laminate is photographed at 5 points using a 150x objective lens from the direction perpendicular to the plane of the conductive layer. , saved as an image. The obtained image was subjected to image analysis using analysis application software VK-H1XA manufactured by Keyence Corporation, and the arithmetic mean value of the area occupied by the metal nanowires in the plane of the conductive layer at the five points was calculated. The calculated average value was converted to an aperture ratio.
In the case of the metal mesh of Comparative Example 2, it was calculated from the line width (5 μm) of the metal portion and the pitch (120 μm) (aperture ratio: 92.2%).
<Optical properties>
Each transparent conductive film laminate obtained in each of the above Examples and Comparative Examples was measured with a Haze meter NDH 2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<Tensile properties>
For the tensile test, test pieces obtained by cutting each transparent conductive film laminate obtained in each of the above Examples and Comparative Examples into strips having a width of 30 mm and a length of 160 mm were used. Marked lines were drawn at intervals of 10 mm in portions corresponding to the gaps between the chucks in advance, the sample was divided into 10 portions, the sheet resistance value of each portion was measured, and the average value was taken as _R0 . After that, the test piece was set in a precision universal tester (Autograph AG-X manufactured by Shimadzu Corporation). The chuck-to-chuck distance during setting was 100 mm, and was extended to 10% at a test speed of 50 mm/min and a test temperature of 155°C. After the test, the sheet resistance values at 10 points were measured again to obtain an average value, which was defined as R.
R/R ₀ was calculated from the resistance values R ₀ and R before and after the tensile test, and the change in resistance at 10% tension was obtained.

The thermoplastic resin-derived component (% by mass) of the protective film in Table 1 is the composition (nonvolatile content (solid content)) of each protective film ink used in each example and comparative example [polyurethane containing a carboxy group, epoxy It was calculated from the ratio (% by mass) of [polyurethane containing a carboxy group or Ethocel (registered trademark)] to the total amount of compound and curing accelerator].

As described above, the transparent conductive film laminate obtained in each of Examples 1 to 5 and the three-dimensionally molded projection type touch panel using each were produced, and it was confirmed that the touch panel operated without any problem. was done. On the other hand, none of the three-dimensionally molded projection touch panels obtained from Comparative Examples 1 and 2 could operate.
Especially in Comparative Example 2, the metal mesh has a line width of 5 μm, a pitch interval of 120 μm, and an aperture ratio of 92.2%. In order to prevent disconnection of the metal mesh and enable the touch panel to operate after three-dimensional molding, it is necessary to increase the strength of the metal mesh. In order to increase the strength, it is necessary to reduce the aperture ratio and set the line width of the mesh to about 10 to 15 μm.

Example 6
Using the same transparent conductive film laminate as in Example 2, <production of electrode rows by laser etching>, <production of wiring by silver paste printing> and <flexible printed wiring board and transparent conductive film laminate in the same manner as in Example 2 Joining> was performed.
Subsequently, "CS9864UAS" (manufactured by Nitto Denko Corporation, 100 µm thick) was used as the two double-sided adhesive sheets, and "polycarbonate film: Iupilon (registered trademark) MRS58HRB manufactured by Mitsubishi Gas Chemical Company, Inc." (2000 µm thick) was used as the cover film. A touch panel test piece was produced in the same manner as in <Lamination using optical double-sided pressure-sensitive adhesive sheet>.
For the obtained touch panel test piece, instead of the mold, the touch panel 36 for the in-vehicle center console shown in FIG. Approximately rectangular parallelepiped with a height of 1 cm), and a curved surface having a second input area 38 (a bottom diameter of about 3 cm, an upper surface diameter of about 2 cm, and a truncated cone shape with a height of about 1 cm). >, and the touch panel 36 was formed. However, a signal detected from the second input region 38 is transmitted between the first input region 37 and the second input region 38 so that the input operation to the first input region 37 can also be driven by the input operation to the second input region 38 . The program was changed to output to area 38.
When driving confirmation was performed on the obtained touch panel, it was confirmed that the display driving in the first input area 37 was driven by the operation to the first input area 37, and the desired display was driven by the operation to the second input area 38. It was confirmed that both the display in the 1st input area 37 and the display in the 2nd input area 38 were driven.

DESCRIPTION OF SYMBOLS 1... Transparent conductive pattern film, 2... Electrode row, 3... Lead line, 3'... Flexible printed circuit board, 11... Touch panel, 12... Touch panel built-in display (input/output integrated display), 13... Display, 15... Detection circuit , 16... cover film, 18... transparent conductive film laminate, 24... film-like substrate, 26A... first transparent conductive pattern film, 26B... second transparent conductive pattern film, 28A... first protective film, 28B... second 2 Protective film 30 Adhesive layer 32 Touch panel 33 Cylindrical surface 34 Touch panel 35 Spherical surface 36 Touch panel 37 First input area 38 Second input area 39 Curved surface area

Claims

a film-like substrate;
A touch panel having a curved region, comprising at least two layers of a transparent conductive pattern film formed on at least one surface of the base material,
The transparent conductive pattern film contains conductive fibers, has an aperture ratio of 40% or more and 70% or less, has an electrode array formed of a conductive region and a non-conductive region, and the transparent conductive pattern including an input area formed by an array of membrane electrodes;
A touch panel, wherein at least a part of the electrode array is arranged in the curved surface region and includes a lead line connected to the electrode array.
The touch panel according to claim 1, wherein the conductive fibers include metal nanowires with an average diameter of 1 nm or more and 500 nm or less.
The touch panel according to claim 1 or 2, wherein the conductive fibers have an average length of 1 μm or more and 100 μm or less, and an average aspect ratio of 5 or more.
The touch panel according to claim 1 or 2, wherein the conductive fibers contain one or more metals selected from the group of gold, silver, copper and aluminum.
The substrate is made of a transparent thermoplastic resin film,
The touch panel according to claim 1, wherein the transparent conductive pattern film contains a binder resin and metal nanowires.
The binder resin is a polymer or cellulose resin containing 70 mol% or more of N-vinylacetamide (NVA) as a monomer unit,
Having a protective film formed on the transparent conductive pattern film,
The touch panel according to claim 5, wherein the protective film contains a resin component, and 94% by mass or more of the resin component is derived from a thermoplastic resin.
The touch panel according to claim 5, wherein the transparent thermoplastic resin film is a polycarbonate film.
The touch panel according to claim 6 or 7, wherein the binder resin is poly-N-vinylacetamide.
The touch panel according to claim 6 or 7, wherein the resin component constituting the protective film is derived from a thermoplastic resin containing polyurethane or ethyl cellulose containing a carboxy group.
The resin component constituting the protective film is derived from a polyurethane containing a carboxy group and an epoxy resin having two or more epoxy groups in one molecule,
The content of the epoxy resin having two or more epoxy groups in one molecule is more than 0% by mass and 6% by mass or less in the resin component, and the carboxy group (COOH ) of the epoxy group (Ep) possessed by the epoxy resin having two or more epoxy groups in one molecule (Ep/COOH) is greater than 0 and 0.02 or less,
The touch panel according to claim 9.
The touch panel according to claim 1 or 2, wherein there are a plurality of input areas formed by the electrode rows of the transparent conductive pattern film, and each input area has a different shape.
3. The input area includes a first input area and a second input area, and the touch panel can be driven by an operation in the first input area also by an operation in the second input area. Described touch panel.
The touch panel according to claim 1 or 2, wherein the curved surface area is a three-dimensional curved surface.
As the transparent conductive pattern film, two types of a first transparent conductive pattern film and a second transparent conductive pattern film are provided,
3. A step of forming a transparent conductive film laminate in which said first transparent conductive pattern film and said second transparent conductive pattern film are respectively laminated on both main surfaces of said base material into said curved surface region by heat forming. 2. The method for manufacturing the touch panel according to 1.
As the transparent conductive pattern film, two types of a first transparent conductive pattern film and a second transparent conductive pattern film are provided,
A first transparent conductive film laminate in which the first transparent conductive pattern film is formed only on one main surface of the first substrate; and a second transparent conductive pattern film is formed on the second substrate. A second transparent conductive film laminate formed only on one main surface of the touch panel according to claim 1, comprising a step of joining and integrating through an adhesive layer, and then forming the curved surface region by heating forming. manufacturing method.
16. The method according to claim 14 or 15, comprising the step of forming a first transparent conductive pattern film having an electrode row and a second transparent conductive pattern film having the electrode row by laser etching a transparent conductive film containing metal nanowires. A method of manufacturing the described touch panel.
a display;
3. An input/output integrated display device comprising the touch panel according to claim 1 or 2 arranged on the display.
An in-vehicle display comprising the input/output integrated display device according to claim 17.