KR102667935B1 - Conductive film and touch panel - Google Patents

Abstract

The conductive film includes a transparent base material, an intermediate layer, a transparent conductive layer, and a metal layer in this order. The thickness of the metal layer is 100 nm or more and 400 nm or less, the refractive index of the middle layer is 1.60 or more and 1.70 or less, the middle layer contains an inorganic particle component containing silica particles and inorganic particles other than silica particles, and the middle layer contains The content ratio of the inorganic particle component is 40.0 mass% or more and 66.0 mass% or less.

Description

Conductive film and touch panel

The present invention relates to a conductive film and a touch panel including the same.

Conventionally, it has been known that image display devices include a touch panel film on which a transparent conductive layer made of indium tin composite oxide (ITO) or the like is formed. Recently, in such a transparent conductive film, in order to achieve frame narrowing by forming a circumferential wiring on the outer edge of the touch input area, a conductive film that forms a copper layer in addition to the surface of the ITO layer has been proposed (e.g. For example, see Patent Document 1).

Such a conductive film is manufactured, for example, by sequentially laminating a transparent conductor layer and a copper layer on one side of a film substrate by a sputtering method and winding them into a roll.

Japanese Patent Publication No. 2013-161282

However, since the transparent conductive layer is prone to peeling off from the transparent substrate, forming an adhesion layer between the transparent conductive layer and the transparent substrate is being studied.

On the other hand, as the size of the touch panel increases, it is necessary to form narrow and long circumferential wiring in the frame portion, and it is required to increase the conductivity of the metal layer. Therefore, reduction of the surface resistance value of the metal layer is being studied, and specifically, making the metal layer a film thickness of 100 nm or more is being studied.

However, when a thick metal layer is formed on the transparent conductive layer by the sputtering method and wound into a roll, the deformation of the metal layer becomes strong, so the metal layer deforms the transparent conductive layer in the plane direction. As a result, even if an adhesion layer is formed between the transparent conductive layer and the transparent substrate, a problem occurs in that the metal layer and the transparent conductive layer peel from the transparent substrate. In other words, simply forming a general adhesion layer between the transparent conductive layer and the transparent substrate is insufficient for adhesion between the transparent conductive layer and the transparent substrate.

Additionally, when the transparent conductive layer is formed with a predetermined wiring pattern, it is necessary to form a conductive film so that the wiring pattern cannot be visually recognized. However, when an adhesion layer is formed to improve adhesion, the wiring pattern may be visible due to the influence of the refractive index and the like.

Additionally, the transparent conductive layer is required to have excellent conductivity. That is, it is required to reduce the surface resistance of the transparent conductive layer. However, there are cases where the surface resistance value of the transparent conductive layer is not reduced due to the influence of the adhesion layer adjacent to the transparent conductive layer.

The present invention aims to provide a conductive film and a touch panel in which the transparent conductive layer has good conductivity and the adhesion between the metal layer and the transparent substrate is improved while suppressing visibility of the wiring pattern of the transparent conductive layer.

The present invention [1] includes a transparent base material, an intermediate layer, a transparent conductive layer, and a metal layer in this order, the thickness of the metal layer is 100 nm or more and 400 nm or less, and the refractive index of the intermediate layer is 1.60 or more and 1.70 or less, The intermediate layer contains an inorganic particle component containing silica particles and inorganic particles other than silica particles, and the content ratio of the inorganic particle component in the intermediate layer is 40.0% by mass or more and 66.0% by mass or less. I'm doing it.

This invention [2] includes the conductive film according to [1], wherein the thickness of the intermediate layer is 30 nm or more and 150 nm or less.

This invention [3] includes the conductive film according to [1] or [2], wherein the content ratio of the inorganic particle component in the intermediate layer is 50.0 mass% or more and 60.0 mass% or less.

This invention [4] includes the conductive film according to any one of [1] to [3], wherein the intermediate layer is a resin layer containing the inorganic particle component.

This invention [5] includes the conductive film according to any one of [1] to [4], wherein the inorganic particles other than the silica particles are zirconium oxide.

The present invention [6] includes the conductive film according to any one of [1] to [5], wherein the metal layer contains at least one of copper, nickel, chromium, iron, and titanium.

The present invention [7] includes the conductive film according to any one of [1] to [6], in which both the transparent conductive layer and the metal layer are patterned.

This invention [8] includes the conductive film according to any one of [1] to [7], which is wound into a roll.

This invention [9] includes a touch panel provided with the conductive film according to any one of [1] to [8].

The conductive film and touch panel of the present invention have good adhesion between the metal layer and the transparent substrate. Additionally, visibility of the wiring pattern of the transparent conductive layer can be suppressed. Additionally, the conductivity of the transparent conductive layer is good.

1 shows a side cross-sectional view of one embodiment of the conductive film of the present invention.
FIG. 2 shows a side cross-sectional view of a patterned conductive film formed from the conductive film shown in FIG. 1.
Figure 3 shows a side cross-sectional view of another embodiment of the conductive film of the present invention (a form without a hard coat layer).
Fig. 4 shows a side cross-sectional view of another embodiment of the patterned conductive film of the present invention (a form without a hard coat layer).

Embodiments of the present invention will be described below with reference to the drawings. In Fig. 1, the vertical direction of the paper is the vertical direction (thickness direction, first direction), with the upper side of the paper being the upper side (one side of the first direction, one side of the thickness direction), and the lower side of the paper being the lower side (the other side of the thickness direction, the first direction). 1 direction (other side). Additionally, the left-right direction of the page is the left-right direction (the second direction, the width direction, the direction perpendicular to the vertical direction), where the left side of the page is the left (one side of the second direction), and the right side of the page is the right side (the other side of the second direction). . In addition, the paper thickness direction is the front-to-back direction (the third direction, a direction perpendicular to both the up-down direction and the left-right direction), with the front side of the page being the front side (one side of the third direction), and the inside of the page being the back side (the other third direction). side). Other drawings are also similar to FIG. 1.

<First embodiment>

1. Conductive film

For example, as shown in FIG. 1, the conductive film 1, which is the first embodiment of the conductive film of the present invention, has a film shape (including a sheet shape) extending in the plane direction and having a predetermined thickness. have The film shape is defined as a thin plate shape having a flat upper surface and a flat lower surface (hereinafter the same applies).

The conductive film 1 is, for example, a part of the base material for a touch panel provided in an image display device, and in other words, it is not an image display device. That is, the conductive film 1 is a component for manufacturing an image display device, etc., and does not include an image display element such as an LCD module, but rather includes a transparent substrate 2, a hard coat layer 3, and an intermediate layer 4, which will be described later. ) and a transparent conductive layer (5) and a metal layer (6), and is distributed as a component alone, making it an industrially usable device.

Specifically, as shown in FIG. 1, the conductive film 1 includes a transparent substrate 2, a hard coat layer 3, an intermediate layer 4, a transparent conductive layer 5, and a metal layer 6. ) are provided in order. More specifically, the conductive film (1) includes a transparent substrate (2), a hard coat layer (3) disposed on the upper surface (one side) of the transparent substrate (2), and a transparent substrate (2) on the upper surface of the hard coat layer (3). It is provided with an intermediate layer (4) disposed, a transparent conductive layer (5) disposed on the upper surface of the intermediate layer (4), and a metal layer (6) disposed on the upper surface of the transparent conductive layer (5). The conductive film (1) preferably consists of a transparent base material (2), a hard coat layer (3), an intermediate layer (4), a transparent conductive layer (5), and a metal layer (6). Below, each layer is described in detail.

2. Transparent substrate

The transparent substrate 2 is a substrate that ensures the mechanical strength of the conductive film 1. The transparent base material 2 supports the transparent conductive layer 5 and the metal layer 6 together with the hard coat layer 3 and the intermediate layer 4.

The transparent substrate 2 is, for example, a polymer film having transparency. Materials for the polymer film include, for example, polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and (meth)acrylic resins such as polymethacrylate (acrylic resin). Resins and/or methacrylic resins), such as polyethylene, polypropylene, olefin resins such as cycloolefin polymers (COP), such as polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, Examples include polyamide resin, polyimide resin, cellulose resin, polystyrene resin, and norbornene resin. The polymer film can be used alone or in combination of two or more types.

From the viewpoint of transparency, heat resistance, mechanical strength, etc., polyester resins and olefin resins are preferred, and PET and COP are more preferred.

The thickness of the transparent substrate 2 is, for example, 2 μm or more, preferably 20 μm or more, from the viewpoint of mechanical strength, scratch resistance, and dot characteristics when the conductive film 1 is used as a touch panel film. And, for example, it is 300 μm or less, preferably 150 μm or less.

The thickness of the transparent substrate 2 can be measured using, for example, a film thickness gauge (digital dial gauge).

Additionally, an easy-adhesion layer, an adhesive layer, a separator, etc. may be formed on the upper and/or lower surfaces of the transparent substrate 2 as needed.

3. Hard coat layer

The hard coat layer 3 provides scratch protection to prevent traces of rubbing on the surface of the conductive film 1 (i.e., the upper surface of the metal layer 6), such as when multiple conductive films 1 are laminated. It's a floor. Additionally, it can be used as an anti-blocking layer to provide blocking resistance to the conductive film 1.

The hard coat layer 3 has a film shape, and is arranged, for example, on the entire upper surface of the transparent substrate 2 so as to contact the upper surface of the transparent substrate 2. More specifically, the hard coat layer 3 is disposed between the transparent substrate 2 and the intermediate layer 4 so as to contact the upper surface of the transparent substrate 2 and the lower surface of the intermediate layer 4.

The hard coat layer 3 is formed, for example, from a hard coat composition. The hard coat composition contains a resin component, and preferably consists of a resin component.

Examples of the resin component include curable resin, thermoplastic resin (for example, polyolefin resin), and preferably curable resin.

Examples of the curable resin include active energy ray curable resins that are cured by irradiation of active energy rays (specifically, ultraviolet rays, electron beams, etc.), and thermosetting resins that are cured by heating, for example. , preferably an active energy ray curable resin.

Examples of the active energy ray-curable resin include polymers having a functional group having a polymerizable carbon-carbon double bond in the molecule. Examples of such functional groups include vinyl group, (meth)acryloyl group (methacryloyl group and/or acryloyl group), and the like.

Specific examples of the active energy ray-curable resin include (meth)acrylic UV-curable resins such as urethane acrylate and epoxy acrylate.

Moreover, examples of curable resins other than active energy ray curable resins include urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates.

These resin components can be used individually or in combination of two or more types.

The resin component may contain resin additives such as a polymerization initiator.

Examples of the polymerization initiator include radical polymerization initiators such as photopolymerization initiators and thermal polymerization initiators. These polymerization initiators can be used individually or in combination of two or more types.

Examples of the photopolymerization initiator include benzoin ether compounds, acetophenone compounds, α-ketol compounds, aromatic sulfonyl chloride compounds, photoactive oxime compounds, benzoin compounds, benzyl compounds, benzophenone compounds, thioxanthone compounds, α-aminoketone compounds, etc. can be mentioned.

Examples of thermal polymerization initiators include organic peroxides and azo compounds.

The hard coat composition may contain particles.

Examples of particles include inorganic particles and organic particles. Examples of the inorganic particles include silica particles, metal oxide particles such as zirconium oxide, titanium oxide, zinc oxide, and tin oxide, and carbonate particles such as calcium carbonate. Examples of organic particles include crosslinked acrylic resin particles. Particles can be used alone or in combination of two or more types.

The hard coat composition may further contain known additives such as leveling agents, thixotropic agents, and antistatic agents.

The thickness of the hard coat layer 3 is, for example, 0.5 μm or more, preferably 1.0 μm or more, and for example, 10 μm or less, preferably 3.0 μm or less, more preferably 2.0 μm or less. am. The thickness of the hard coat layer 3 can be measured using, for example, a film thickness gauge (digital dial gauge).

4. Middle layer

The intermediate layer 4 improves the adhesion between the metal layer 6 side (particularly the transparent conductive layer 5) and the transparent substrate 2 side (particularly the hard coat layer 3) of the conductive film 1. , It is an adhesion layer to suppress interlayer peeling inside the conductive film (1). In addition, optical adjustment is performed to adjust the optical properties (e.g., refractive index) of the conductive film 1 in order to ensure excellent transparency of the conductive film 1 while suppressing visibility of the wiring pattern of the transparent conductive layer 5. It is also a layer.

The intermediate layer 4 has a film shape, and is arranged, for example, on the entire upper surface of the hard coat layer 3 so as to contact the upper surface of the hard coat layer 3. More specifically, the intermediate layer 4 is disposed between the hard coat layer 3 and the transparent conductive layer 5 so as to contact the upper surface of the hard coat layer 3 and the lower surface of the transparent conductive layer 5. .

The intermediate layer 4 is formed from an intermediate layer composition. The intermediate layer composition preferably contains an inorganic particle component and a resin component, and more preferably consists of an inorganic particle component and a resin component. That is, the intermediate layer 4 is preferably a resin layer containing an inorganic particle component, and more preferably a resin layer consisting of an inorganic particle component and a resin component.

Examples of the resin component include the same resin as the resin used in the hard coat composition. Resins can be used alone or in combination of two or more types. Preferably, curable resin is used, and more preferably, active energy ray-curable resin is used.

The content ratio of the resin component is, for example, 34.0 mass% or more, preferably 40.0 mass% or more, and for example, 60.0 mass% or less, preferably 50.0 mass% or less, with respect to the intermediate layer composition. Preferably it is 45.0 mass% or less.

The inorganic particle component contains silica particles and inorganic particles other than silica particles (hereinafter also referred to as second inorganic particles).

The second inorganic particles preferably include inorganic particles with a higher refractive index than the silica particles (for example, a refractive index of 2.00 or more), and specifically include zirconium oxide particles, titanium oxide particles, zinc oxide particles, etc. Metal oxide particles can be mentioned. From the viewpoint of adhesion and suppression of visibility of the wiring pattern, zirconium oxide particles are preferably used. These second inorganic particles can be used individually or in combination of two or more types.

The inorganic particle component preferably contains silica particles and metal oxide particles, more preferably contains silica (SiO ₂ ) particles and zirconium oxide (ZnO ₂ ) particles, and even more preferably contains silica particles and zirconium oxide particles. It consists of

The content ratio of silica particles in the inorganic particle component is, for example, 1.0 mass% or more, preferably 3.0 mass% or more, more preferably 5.0 mass% or more, and for example, 50.0 mass% or less. , Preferably it is 20.0 mass% or less, and more preferably, it is 15.0 mass% or less. If the content ratio of silica particles is within the above range, adhesion can be further improved. Additionally, the surface resistance value of the transparent conductive layer 5 can be further reduced.

The content ratio of the second inorganic particles in the inorganic particle component is, for example, 50.0 mass% or more, preferably 80.0 mass% or more, more preferably 85.0 mass% or more, and for example, 99.0 mass% or more. % or less, preferably 97.0 mass% or less, more preferably 95.0 mass% or less. If the content ratio of the second inorganic particles is within the above range, the refractive index of the intermediate layer 4 can be improved, and the refractive index of the intermediate layer 4 can be easily adjusted to the range of 1.60 or more and 1.70 or less. As a result, visibility of the wiring pattern of the transparent conductive layer 5 can be further suppressed.

The average particle diameter of the silica particles is, for example, 1 nm or more, preferably 5 nm or more, and, for example, 100 nm or less, preferably 50 nm or less.

The average particle diameter of the second inorganic particles is, for example, 10 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 50 nm or less.

The average particle diameter of particles represents the average particle diameter (D ₅₀ ) of the particle size distribution based on volume, and can be measured, for example, by an optical diffraction/scattering method in a solution in which particles are dispersed in water.

The content ratio of the inorganic particle component is 40.0% by mass or more and 66.0% by mass or less with respect to the middle layer composition (further, the middle layer (4)). Preferably it is 50.0 mass% or more, more preferably 55.0 mass% or more, and preferably 60.0 mass% or less. When the content ratio of the inorganic particle component exceeds the above upper limit, the adhesiveness decreases or the surface resistance value of the transparent conductive layer 5 increases. Moreover, when the content ratio of the inorganic particle component is less than the above lower limit, the wiring pattern of the transparent conductive layer 5 becomes easily visible.

The refractive index of the intermediate layer 4 is 1.60 or more and 1.70 or less. Preferably it is 1.62 or more, and more preferably, it is 1.68 or less. If the refractive index of the intermediate layer 4 is within the above range, visibility of the wiring pattern of the transparent conductive layer 5 can be suppressed.

The refractive index can be measured, for example, with an Abbe refractometer under conditions of a wavelength of 589 nm.

The thickness of the intermediate layer 4 is, for example, 10 nm or more, preferably 30 nm or more, and, for example, 300 nm or less, preferably 150 nm or less. If the thickness of the intermediate layer 4 is within the above range, visibility of the wiring pattern of the transparent conductive layer 5 can be further suppressed.

The thickness of the intermediate layer 4 can be measured by observing the cross section of the conductive film 1 using, for example, a transmission electron microscope.

5. Transparent conductive layer

The transparent conductive layer 5 is formed in a wiring pattern (patterned transparent conductive layer 5A described later) in a later process, for example, as a wiring pattern (for example, electrode wiring) in the touch input area of the touch panel. ) is a transparent conductive layer to form.

The intermediate layer 4 has a film shape, and is arranged, for example, on the entire upper surface of the intermediate layer 4 so as to contact the upper surface of the intermediate layer 4. More specifically, the transparent conductive layer 5 is disposed between the intermediate layer 4 and the metal layer 6 so as to contact the upper surface of the intermediate layer 4 and the lower surface of the metal layer 6.

The material of the transparent conductive layer 5 is, for example, selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. and metal oxides containing at least one type of metal. If necessary, the metal oxide may be further doped with a metal atom shown in the above group.

The material of the transparent conductive layer 5 includes, for example, indium-containing oxides such as indium tin composite oxide (ITO), and antimony-containing oxides such as antimony tin composite oxide (ATO), etc., and are preferred. Examples include indium-containing oxides, more preferably ITO.

When ITO is used as the material of the transparent conductive layer 5, the tin oxide (SnO ₂ ) content is preferably, for example, 0.5% by mass or more relative to the total amount of tin oxide and indium oxide (In ₂ O ₃ ). Typically, it is 3% by mass or more, and for example, it is 15% by mass or less, preferably 13% by mass or less. By setting the tin oxide content to the above lower limit or more, the durability of the ITO layer can be further improved. By setting the tin oxide content below the above upper limit, crystal conversion of the ITO layer can be facilitated and transparency and stability of resistivity can be improved.

“ITO” in this specification may be a complex oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Additional components include, for example, metal elements other than In and Sn, and specifically include Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. , Fe, Pb, Ni, Nb, Cr, Ga, etc.

The thickness of the transparent conductive layer 5 is, for example, 10 nm or more, preferably 20 nm or more, and is, for example, 50 nm or less, preferably 30 nm or less.

The thickness of the transparent conductive layer 5 can be measured, for example, by observing the cross section of the conductive film 1 using a transmission electron microscope.

The transparent conductive layer 5 may be either crystalline or amorphous, or may be a mixture of crystalline and amorphous. The transparent conductive layer 5 is preferably made of crystalline material, and more specifically, is a crystalline ITO layer. Thereby, the transparency of the transparent conductive layer 5 can be improved, and the surface resistance value of the transparent conductive layer 5 can be further reduced.

The transparent conductive layer 5 is crystalline, for example, when the transparent conductive layer 5 is an ITO layer, it is immersed in hydrochloric acid (concentration 5% by mass) at 20°C for 15 minutes, then washed with water and dried. This can be determined by measuring the resistance between terminals in the order of mm. In this specification, if the resistance between terminals over 15 mm is 10 kΩ or less after immersion in hydrochloric acid (20°C, concentration: 5% by mass), washing with water, and drying, the ITO layer is considered to be crystalline.

The surface resistance value of the transparent conductive layer 5 (especially the crystalline ITO layer) is, for example, less than 100 Ω/□, preferably 80 Ω/□ or less, more preferably 75 Ω/□ or less, and For example, 10 Ω/□ or more. The surface resistance value can be measured by the four-terminal method, for example, based on JIS K 7194 (1994).

6. Metal layer

The metal layer 6 is formed on a wiring pattern (patterned metal layer 6A, described later) in a later process, for example, on the outer edge (outer periphery) of the touch input area of the touch panel. It is a conductive metal layer for forming a pattern (for example, a circumferential wiring).

The metal layer 6 is the uppermost layer of the conductive film 1, has a film shape, and is disposed on the entire upper surface of the transparent conductive layer 5 so as to contact the upper surface of the transparent conductive layer 5.

Examples of the material of the metal layer 6 include metals such as copper, nickel, chromium, iron, titanium, or alloys thereof. From the viewpoint of conductivity and the like, copper is preferred.

Additionally, when the metal layer 6 is made of a material such as copper that is prone to oxidation, the surface of the metal layer 6 may be oxidized. Specifically, when the metal layer 6 is a copper layer, the metal layer 6 may be a copper layer including copper oxide on part or all of the surface.

The thickness of the metal layer 6 is 100 nm or more and 400 nm or less. Preferably it is 150 nm or more, and more preferably, it is 300 nm or less. If the thickness of the metal layer 6 is less than the above lower limit, the surface resistance value of the metal layer 6 increases and conductivity decreases. Therefore, in response to the increase in the size of the touch panel, it becomes difficult to form a narrow and long wiring pattern (circular wiring in the frame portion). Moreover, if the thickness of the metal layer 6 exceeds the above upper limit, the improvement in conductivity is saturated and it becomes disadvantageous in terms of cost. Additionally, it becomes difficult to thin the frame portion.

The thickness of the metal layer 6 can be measured by observing the cross section of the conductive film 1 using, for example, a transmission electron microscope.

7. Method of manufacturing conductive film

To manufacture the conductive film 1, for example, in a roll-to-roll process, a hard coat layer 3, an intermediate layer 4, a transparent conductive layer 5, and a metal layer are applied to one side of the transparent substrate 2. (6) is formed in order. That is, while the transparent substrate 2, which is long in the longitudinal direction, is fed out from the delivery roll and conveyed downstream in the conveyance direction, the hard coat layer 3 is formed on the upper surface of the transparent substrate 2, and then the hard coat layer 3 is formed. ), forming an intermediate layer (4) on the upper surface of the intermediate layer (4), then forming a transparent conductive layer (5) on the upper surface of the intermediate layer (4), and then forming a metal layer (6) on the upper surface of the transparent conductive layer (5), The conductive film 1 is wound with a winding roll. Below, it is described in detail.

First, a long transparent substrate 2 wound around a delivery roll is prepared, and the transparent substrate 2 is conveyed so that it is wound around a take-up roll.

Thereafter, if necessary, from the viewpoint of adhesion between the transparent substrate 2 and the hard coat layer 3, the surface of the transparent substrate 2 is subjected to, for example, sputtering, corona discharge, flame, ultraviolet irradiation, or electron beam irradiation. , etching treatment or primer treatment such as chemical conversion or oxidation can be performed. Additionally, the transparent substrate 2 can be dusted and cleaned by solvent cleaning, ultrasonic cleaning, etc.

Next, a hard coat layer (3) is formed on the upper surface of the transparent substrate (2). For example, the hard coat layer 3 is formed on the upper surface of the transparent substrate 2 by wet coating the hard coat composition on the upper surface of the transparent substrate 2.

Specifically, for example, a hard coat composition coating liquid is prepared by diluting the hard coat composition with a solvent, and then the coating liquid is applied to the upper surface of the transparent base material 2 and dried.

Examples of the solvent include organic solvents and aqueous solvents (specifically, water), and organic solvents are preferred. Organic solvents include, for example, alcohol compounds such as methanol, ethanol and isopropyl alcohol, ketone compounds such as acetone, methyl ethyl ketone and methyl isobutyl ketone, such as ethyl acetate and butyl acetate. ester compounds, ether compounds such as propylene glycol monomethyl ether, and aromatic compounds such as toluene and xylene. These solvents can be used individually or in combination of two or more types. Preferred examples include ester compounds and ether compounds.

The solid content concentration in the coating liquid is, for example, 1% by mass or more, preferably 10% by mass or more, and for example, 30% by mass or less, preferably 20% by mass or less.

The application method can be appropriately selected depending on the coating liquid and transparent substrate (2). For example, the dip coat method, air knife coat method, curtain coat method, roller coat method, wire bar coat method, gravure coat method, inkjet method, etc. are mentioned.

The drying temperature is, for example, 50°C or higher, preferably 60°C or higher, for example, 200°C or lower, preferably 150°C or lower.

The drying time is, for example, 0.5 minutes or more, preferably 1 minute or more, for example, 60 minutes or less, preferably 20 minutes or less.

Then, when the hard coat composition contains an active energy ray curable resin, the active energy ray curable resin is cured by irradiating an active energy ray after drying the coating liquid.

In addition, when the hard coat composition contains a thermosetting resin, the thermosetting resin can be thermoset along with drying the solvent through this drying process.

Next, the intermediate layer 4 is formed on the upper surface of the hard coat layer 3. For example, the intermediate layer 4 is formed on the upper surface of the hard coat layer 3 by wet coating the intermediate layer composition on the upper surface of the hard coat layer 3.

Specifically, for example, an intermediate layer composition coating liquid is prepared by diluting the intermediate layer composition with a solvent as necessary, and then the coating liquid is applied to the upper surface of the hard coat layer 3 and dried.

Conditions for preparation, application, drying, etc. of the intermediate layer composition may be the same as the conditions for preparation, application, drying, etc. exemplified for the hard coat composition.

Then, when the intermediate layer composition contains an active energy ray-curable resin, the active energy ray-curable resin is cured by irradiating an active energy ray after drying the coating liquid.

Additionally, when the intermediate layer composition contains a thermosetting resin, the thermosetting resin can be thermoset along with drying the solvent through this drying process.

Next, a transparent conductive layer (5) is formed on the upper surface of the intermediate layer (4). For example, the transparent conductive layer 5 is formed on the upper surface of the intermediate layer 4 by a dry method.

Examples of dry methods include vacuum deposition, sputtering, and ion plating. Preferably, the sputtering method is used. By this method, the transparent conductive layer 5 that is thin and has a uniform thickness can be formed.

In the sputtering method, a target and an adherend (a transparent substrate (2) on which an intermediate layer (4) and a hard coat layer (3) are laminated) are placed facing each other in a vacuum chamber, gas is supplied, and a voltage is applied from a power source to produce gas ions. is accelerated and irradiated to the target, the target material is ejected from the target surface, and the target material is laminated on the surface of the adherend.

Examples of the sputtering method include the two-pole sputtering method, ECR (electron cyclotron resonance) sputtering method, magnetron sputtering method, and ion beam sputtering method. Preferably, the magnetron sputtering method is used.

When employing the sputtering method, target materials include the above-mentioned metal oxides constituting the transparent conductive layer 5, and preferably ITO. The tin oxide concentration of ITO is, for example, 0.5 mass% or more, preferably 3 mass% or more, and, for example, 15 mass% or less, preferably, from the viewpoint of durability of the ITO layer, crystallization, etc. It is 13% by mass or less.

Examples of the gas include inert gas such as Ar. Additionally, if necessary, a reactive gas such as oxygen gas can be used together. When using a reactive gas together, the flow rate ratio (sccm) of the reactive gas is not particularly limited, but is, for example, 0.1 flow rate% or more and 5 flow rate% or less with respect to the total flow rate ratio of the sputter gas and the reactive gas.

The atmospheric pressure during sputtering is, for example, 1 Pa or less, and is preferably 0.1 Pa or more and 0.7 Pa or less from the viewpoint of suppressing a decrease in the sputtering rate, discharge stability, etc.

The power supply may be, for example, any of DC power, AC power, MF power, and RF power, or may be a combination of these.

Next, a metal layer (6) is formed on the upper surface of the transparent conductive layer (5). For example, the metal layer 6 is formed on the upper surface of the transparent conductive layer 5 by a dry method.

Dry methods include the same methods as those described above for forming the transparent conductive layer 5, and sputtering is preferred. By this method, the metal layer 6 with a uniform thickness can be formed even if it is a thick film.

The conditions of the sputtering method for the metal layer 6 may also be the same as those exemplified in the formation of the transparent conductive layer 5.

In addition, the target material includes the above-mentioned metals constituting the metal layer 6, and copper is preferred.

Next, the obtained long conductive film 1 is wound on a winding roll.

As a result, the conductive film 1 wound into a roll is obtained.

Additionally, if necessary, crystal conversion treatment can be performed on the transparent conductive layer 5 of the conductive film 1. The crystal conversion treatment may be performed on the obtained conductive film (1), or on the conductive film (1) before lamination of the metal layer (6) (intermediate laminate, that is, transparent substrate (2)/hard coat layer (3). )/middle layer (4)/transparent conductive layer (5) laminate).

Specifically, the conductive film (1) or the intermediate laminate is subjected to heat treatment in the air.

Heat treatment can be performed using, for example, an infrared heater or an oven.

The heating temperature is, for example, 100°C or higher, preferably 120°C or higher, and, for example, 200°C or lower, preferably 160°C or lower. By keeping the heating temperature within the above range, crystal transformation can be ensured while suppressing heat damage to the transparent substrate 2 and impurities generated from the transparent substrate 2.

The heating time is appropriately determined depending on the heating temperature, but is, for example, 10 minutes or more, preferably 30 minutes or more, and, for example, 5 hours or less, preferably 3 hours or less.

Thereby, the conductive film (1) provided with the crystallized transparent conductive layer (5) is obtained.

In addition, in the above process, each layer may be wound on a winding roll for each layer formed. In addition, the formation of the hard coat layer 3, the intermediate layer 4, the transparent conductive layer 5, and the metal layer 6 may be carried out continuously without winding, and may be wound on a winding roll after the formation of the metal layer 6.

Additionally, if necessary, before or after the crystal conversion process, the transparent conductive layer 5 and/or the metal layer 6 may be patterned into a stripe-like wiring pattern using a known etching method.

When etching the transparent conductive layer 5 and the metal layer 6, they may be etched simultaneously or separately, but preferably the transparent conductive layer 5 and the metal layer 6 are each etched in separate patterns. In view of being able to form them reliably, these are etched separately.

For example, first, the metal layer 6 is formed so that a desired wiring pattern (for example, a circumferential wiring) is formed at the main end (for example, an area corresponding to the circumferential wiring) when viewed from the plane of the metal layer 6 ( In particular, the central portion (when viewed from the top) is removed by etching. Next, the transparent conductive layer 5 (particularly, the central portion in plan view) exposed from the metal layer 6 is etched so that a desired wiring pattern (for example, a wiring pattern in the touch input area) is formed. Remove.

Accordingly, as shown in FIG. 2, as an embodiment of the conductive film 1, the transparent substrate 2, the hard coat layer 3, the intermediate layer 4, the patterned transparent conductive layer 5A, and the patterned metal layer ( A patterned conductive film (1A) having 6A) is obtained.

Additionally, the patterning metal layer 6A forms a border-shaped frame portion in plan view, and the patterning transparent conductive layer 5A forms a predetermined wiring pattern within the patterning metal layer 6A.

8. Touch panel

The conductive film 1 is used, for example, in a base material for a touch panel provided in an image display device. Types of the touch panel include, for example, various types such as a capacitive type and a resistive type, and are particularly preferably used for a capacitive type touch panel. Specifically, for example, the patterned conductive film 1A is placed on a protective substrate such as protective glass to use it as a touch panel.

In addition, the conductive film (1) is, for example, electrophoretic method, twisted ball method, thermal-rewriteable method, optical recording liquid crystal method, polymer dispersed liquid crystal method, guest/host liquid crystal method, toner display method, and It can also be suitably used in flexible display elements such as mism type and electric field deposition type.

9. Action effect

And this conductive film (1) is provided with a transparent base material (2), an intermediate layer (4), a transparent conductive layer (5), and a metal layer (6) in this order, and the thickness of the metal layer (6) is 100 nm or more. It is 400 nm or less. For this reason, the conductivity (low surface resistance value) of the metal layer 6 can be improved. As a result, a narrow and long wiring pattern (circular wiring) can be reliably formed in the frame portion (end portion) of the touch panel. Therefore, even if the touch panel becomes larger, frame narrowing can be achieved.

Moreover, the refractive index of the middle layer 4 is 1.60 or more and 1.70 or less, the middle layer 4 contains an inorganic particle component containing silica particles and a second inorganic particle, and the inorganic particle component in the middle layer 4 The content ratio is 40.0 mass% or more and 66.0 mass% or less.

For this reason, in the conductive film 1 provided with the thick metal layer 6 (i.e., low surface resistance value), the adhesion between the metal layer 6 and the transparent substrate 2 is good. In particular, the adhesiveness of the interface between the transparent conductive layer 5 and the intermediate layer 4 is good, and cohesive failure can be suppressed between them, so separation of the metal layer 6 and the transparent substrate 2 can be suppressed. . Additionally, when the transparent conductive layer 5 is formed on a wiring pattern (e.g., a pattern in the touch input area of a touch panel; patterned transparent conductive layer 5A), visibility of the wiring pattern can be suppressed. . Additionally, since the conductivity of the transparent conductive layer 5 is good, it has excellent touch response even when the touch panel is enlarged.

Additionally, conventionally, when an adhesion layer is formed between the transparent conductive layer 5 and the transparent substrate 2, there are cases where the wiring pattern of the transparent conductive layer 5 becomes easily visible due to the optical influence of the adhesion layer. do. In addition, since the transparent conductive layer 5 is adjacent to the adhesion layer, it affects the crystallization of the transparent conductive layer 5 and, ultimately, lowering the resistance. Crystallization of the transparent conductive layer is inhibited, and the surface resistance value is reduced. There are cases where this does not work.

On the other hand, in the conductive film (1) of the present invention, the intermediate layer (4) of the above-described specific structure is disposed between the hard coat layer (3) and the transparent conductive layer (5). Therefore, these adhesion properties can be improved, visibility of the wiring pattern can be suppressed, and the surface resistance value can be lowered without inhibiting the crystallization of the transparent conductive layer 5.

＜Modification example＞

In the embodiment shown in FIG. 1, the conductive film 1 is provided with the hard coat layer 3. However, for example, as shown in FIG. 3, the conductive film 1 is provided with the hard coat layer 3. There is no need to provide . That is, the conductive film 1 shown in FIG. 3 consists of a transparent base material 2, an intermediate layer 4, a transparent conductive layer 5, and a metal layer 6.

Moreover, in the embodiment shown in FIG. 2, the patterning conductive film 1A is provided with a hard coat layer 3, but, for example, as shown in FIG. 4, the conductive film 1 has a hard coat layer. (3) It is not necessary to provide. That is, the conductive film 1 shown in FIG. 4 consists of a transparent base material 2, an intermediate layer 4, a patterning transparent conductive layer 5A, and a patterning metal layer 6A.

Also in this embodiment, the same effects as those in the embodiment shown in FIGS. 1 and 2 are achieved. Preferably, from the viewpoint of scratch resistance, the embodiment shown in FIGS. 1 and 3 is given.

In addition, in the embodiment shown in FIGS. 1 and 2, the lower surface of the transparent substrate 2 is exposed. For example, although not shown, the hard coat layer 3 is further formed on the lower surface of the transparent substrate 2. ), the intermediate layer 4, the transparent conductive layer 5, and the metal layer 6 may be provided in whole or in part.

Also in this embodiment, the same effects as those in the embodiment shown in FIGS. 1 and 2 are achieved.

Example

Examples and comparative examples are given below to illustrate the present invention in more detail. Additionally, the present invention is not limited to the Examples and Comparative Examples. The specific values of mixing ratio (content ratio), physical properties, parameters, etc. used in the following description are the corresponding mixing ratio (content ratio) described in the above "Mode for carrying out the invention", Physical properties, parameters, etc. can be replaced with the upper limit value (a value defined as “less than” or “less than”) or a lower limit value (a value defined as “above” or “exceeding”).

(Example 1)

As a long transparent substrate, a cycloolefin polymer film (COP film, manufactured by Nippon Zeon Co., Ltd., “Zeonoa ZF16”) with a thickness of 100 μm was prepared.

A hard coat composition solution was prepared by mixing 100 parts by mass of an ultraviolet curable acrylic resin (“ELS888”, manufactured by DIC), 2 parts by mass of a photopolymerization initiator (“Irgacure184”, manufactured by BASF), and 160 parts by mass of ethyl acetate. The hard coat composition solution was applied to the upper surface of the COP film, dried at 80°C for 1 minute, and then irradiated with ultraviolet rays. In this way, a hard coat layer with a thickness of 2 μm was formed on the upper surface of the COP film.

An intermediate layer composition solution was prepared by mixing 700 parts by mass of propylene glycol monomethyl ether with 100 parts by mass of an inorganic particle-containing resin solution (“KZ6954” manufactured by JSR). The middle layer composition solution was applied to the upper surface of the hard coat layer, dried at 60°C for 1 minute, and then irradiated with ultraviolet rays. In this way, an intermediate layer with a thickness of 100 nm was formed on the upper surface of the hard coat layer.

In addition, the solid content of the inorganic particle-containing resin solution (“KZ6954” manufactured by JSR) was 62.5% by mass of the inorganic particle component and 37.5% by mass of the resin component. Moreover, the inorganic particle component was 19 mass% of silica particles (average particle diameter 10 nm) and 81 mass% of zirconium oxide particles (average particle diameter 25 nm).

Next, the laminate of COP film/hard coat layer/middle layer was put into a winding sputtering device, and an ITO layer (amorphous) with a thickness of 30 nm was formed on the upper surface of the middle layer. Specifically, an ITO target made of a sintered body of 97 mass% indium oxide and 3 mass% tin oxide was used in a vacuum atmosphere with 98% argon gas and 2% oxygen gas and a pressure of 0.4 Pa for the intermediate layer. Sputtering was performed.

Next, the laminate of COP film/hard coat layer/middle layer/ITO layer (amorphous) was put into a winding sputtering device, and a copper layer with a thickness of 200 nm was formed on the upper surface of the ITO layer. Specifically, sputtering was performed on the ITO layer using an ITO target made of oxygen-free copper in a vacuum atmosphere with argon gas and an atmospheric pressure of 0.4 Pa.

In this way, the roll-shaped conductive film of Example 1 was manufactured.

(Examples 2 to 4)

In forming the intermediate layer, an inorganic particle resin solution was prepared by appropriately mixing two types of Offstar KZ series (“KZ6954” and “KZ6956”) manufactured by JSR so that the formulation of the intermediate layer was as shown in Table 1. Other than that, a conductive film was manufactured in the same manner as in Example 1.

In addition, the inorganic particles (silica particles and/or zirconium oxide particles) contained in the Offstar KZ series, Offstar Z series manufactured by JSR, and the "RA017" manufactured by Arakawa Chemical Industry Co., Ltd. used in each Example and each Comparative Example. The types were almost the same.

(Example 5)

In the formation of the intermediate layer, two types of Offstar KZ series manufactured by JSR (25% by mass of "KZ6954" and 75% by mass of "KZ6956") were used so that the prescription of the intermediate layer was the prescription shown in Table 1 and the refractive index was 1.60. 100 parts by mass, and two types of organic resin-containing solutions (17 parts by mass of "Viscot 300" manufactured by Osaka Organic Chemical Industry Co., Ltd. and 18 parts by mass of "KAYARAD BNP-1" manufactured by Nippon Kayak Co., Ltd.) were mixed to form an inorganic particle resin solution. A conductive film was produced in the same manner as in Example 1, except that .

(Example 6)

In forming the intermediate layer, 66 parts by mass of "Offstar Z7414" manufactured by JSR and 34 parts by mass of "RA017" manufactured by Arakawa Chemical Industry Co., Ltd. were used so that the prescription of the intermediate layer was the prescription shown in Table 1 and the refractive index was 1.70. A conductive film was produced in the same manner as in Example 1, except that the inorganic particle resin solution was prepared by mixing.

(Comparative Examples 1 to 5)

In forming the intermediate layer, use Offstar KZ series (“KZ6953”, “KZ6954”, “KZ6956”) or Offstar Z series (“Z7549”) manufactured by JSR so that the prescription of the intermediate layer is the prescription shown in Table 1. A conductive film was produced in the same manner as in Example 1, except that the inorganic particle resin solution was prepared by mixing appropriately.

(Comparative Example 6)

A conductive film was manufactured in the same manner as in Comparative Example 1, except that the thickness of the copper layer was changed to 50 nm.

(thickness of each layer)

The layer with a thickness of less than 1.0 μm was measured by observing the cross section of the conductive film using a transmission electron microscope (“H-7650” manufactured by Hitachi Ltd.). The layer with a thickness of 1.0 μm or more was measured using a membrane thickness gauge (digital dial gauge DG-205 manufactured by Peacock). The results are shown in Table 1.

(refractive index)

The refractive index at a wavelength of 589 nm was measured using an Abbe refractometer (manufactured by Atago).

(adhesion)

On the surface of the copper layer of the conductive film obtained in each example and each comparative example, a cut surface was cut in a checkerboard shape using a cutter knife so that 100 mass scales of 1 mm in width and height were formed (10 rows × 10 columns). formed. Next, an adhesive tape (manufactured by Sekisui Chemical Industries, Ltd., brand name "Sellotape (registered trademark) No. 252") was affixed to the surface of the copper layer on which the cut surface was formed, and then the peeling process was repeated twice. The surface of the copper layer at this time was observed with the naked eye, and adhesion was evaluated as follows. The results are shown in Table 1.

5: No peeling of the copper layer was seen at all (the peeling area was less than 1%)

4: Missing was visible around the cut surface of the crosscut (the peeling area was 1% or more and less than 10%).

3: The peeling area of the copper layer was 10% or more and less than 40%.

2: The peeling area of the copper layer was 40% or more and less than 60%.

1: The peeling area of the copper layer was 60% or more and less than 80%.

0: The peeling area of the copper layer was 80% or more.

In addition, in the above, the adhesion of the copper layer was measured in the conductive film in which the ITO layer is amorphous, but the same measurement results for the adhesion of the copper layer are obtained even when the ITO layer is a crystalline layer.

(Visibility of wiring pattern)

The roll-shaped conductive film obtained in each example and each comparative example was cut into 10 cm did. In this way, a metal layer corresponding to the circumferential wiring of the frame was patterned only at the peripheral edge.

Next, a dry film resist with a predetermined pattern was placed on the central ITO layer when viewed from a plane excluding the frame of the conductive film, and only the ITO layer was etched, and then the resist was removed. In this way, an ITO layer corresponding to a wiring pattern was patterned in the center when viewed in plan view (see FIG. 2).

The wiring pattern of the obtained patterned conductive film was viewed with the naked eye under an LED light source at an inclination of 45 degrees.

Cases where the wiring pattern was not confirmed were evaluated as ○, cases where the wiring pattern was slightly confirmed were evaluated as △, and cases where the wiring pattern was clearly confirmed were evaluated as ×. The results are shown in Table 1.

(Surface resistance value of ITO layer)

In each example and each comparative example, the conductive film (laminated body of COP film/hard coat layer/middle layer/ITO layer (amorphous)) immediately before forming the copper layer was put into an air circulation oven using a roll-to-roll method. Then, heat treatment was performed at 140°C for 60 minutes to crystallize the ITO layer. As a result, a sample for measuring surface resistance (laminated body of COP film/hard coat layer/middle layer/crystalline ITO layer) was obtained.

The surface resistance of the crystalline ITO layer of each sample was measured by the four-terminal method in accordance with JIS K 7194 (1994). The results are shown in Table 1.

(Surface resistance value of copper layer)

The surface resistance value of the copper layer of the roll-shaped conductive film obtained in each example and each comparative example was measured by the four-terminal method. As a result, the surface resistance value (0.6 Ω/□) of the conductive film of Comparative Example 6 was found in each example. and the surface resistance value (0.1 Ω/□) of the conductive films of Comparative Examples 1 to 5.

Additionally, although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be construed as limited. Modifications of the present invention apparent to those skilled in the art are included in the claims described hereinafter.

Industrial applicability

The conductive film and touch panel of the present invention can be applied to various industrial products and are suitably used in, for example, image display devices.

1: Conductive film
2: Transparent substrate
4: middle layer
5: Transparent conductive layer
6: metal layer

Claims (9)

A transparent substrate, an intermediate layer, a transparent conductive layer, and a metal layer are provided in this order,
The thickness of the metal layer is 100 nm or more and 400 nm or less,
The refractive index of the intermediate layer is 1.60 or more and 1.70 or less,
The intermediate layer contains silica particles and an inorganic particle component containing inorganic particles with a higher refractive index than the silica particles, and the ratio of the silica particles to the inorganic particle component is 1 mass% or more and 50 mass% or less,
A conductive film characterized in that the content ratio of the inorganic particle component in the intermediate layer is 40.0 mass% or more and 66.0 mass% or less. According to claim 1,
A conductive film characterized in that the thickness of the intermediate layer is 30 nm or more and 150 nm or less. According to claim 1,
A conductive film characterized in that the content ratio of the inorganic particle component in the intermediate layer is 50.0 mass% or more and 60.0 mass% or less. According to claim 1,
A conductive film characterized in that the intermediate layer is a resin layer containing the inorganic particle component. According to claim 1,
A conductive film characterized in that the inorganic particles having a higher refractive index than the silica particles are zirconium oxide. According to claim 1,
A conductive film characterized in that the metal layer contains at least one of copper, nickel, chromium, iron, and titanium. According to claim 1,
A conductive film characterized in that both the transparent conductive layer and the metal layer are patterned. According to claim 1,
A conductive film, characterized in that it is wound into a roll. A touch panel comprising the conductive film according to any one of claims 1 to 8.