KR20220153659A - Conductive film and touch panel - Google Patents

Abstract

The conductive film includes a transparent substrate, 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 intermediate layer is 1.60 or more and 1.70 or less, the intermediate layer contains inorganic particle components containing silica particles and inorganic particles other than silica particles, and in the intermediate layer 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 {CONDUCTIVE FILM AND TOUCH PANEL}

The present invention relates to a conductive film and a touch panel provided therewith.

Conventionally, it is known that an image display device includes a film for a touch panel having a transparent conductive layer made of indium tin composite oxide (ITO) or the like. In recent years, in such a transparent conductive film, a conductive film in which a copper layer is formed in addition to the surface of the ITO layer has been proposed in order to form a winding wiring on the outer edge of the touch input region to achieve frame narrowing (e.g. For example, see Patent Document 1).

Such a conductive film is manufactured by, for example, sequentially laminating a transparent conductor layer and a copper layer on one side of a film base material by a sputtering method and winding it up in a roll shape.

Japanese Unexamined Patent Publication No. 2013-161282

By the way, since a transparent conductive layer peels easily from a transparent substrate, forming an adhesive layer between a transparent conductive layer and a transparent substrate is examined.

On the other hand, with the increase in the size of the touch panel, it is necessary to form a narrow and long winding 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 a metal layer is studied, and specifically, making a metal layer into a film thickness of 100 nm or more is examined.

However, when a thick metal layer is formed on the transparent conductive layer by sputtering and wound into a roll, the metal layer deforms the transparent conductive layer in the planar direction because the metal layer is deformed. As a result, even if an adhesion layer is formed between the transparent conductive layer and the transparent substrate, the problem that the metal layer and the transparent conductive layer are separated from the transparent substrate arises. That is, the adhesion between the transparent conductive layer and the transparent substrate is insufficient only by forming a general adhesion layer between the transparent conductive layer and the transparent substrate.

In addition, when the transparent conductive layer is formed in a predetermined wiring pattern, it is necessary to form a conductive film so that the wiring pattern cannot be visually recognized. However, when an adhesive layer is formed to improve adhesion, wiring patterns may be visually recognized due to the influence of the refractive index or the like.

In addition, the transparent conductive layer is required to have excellent conductivity. That is, reducing the surface resistance value of the transparent conductive layer is required. However, there occurs a case where the surface resistance value of the transparent conductive layer is not reduced due to the influence of the adhesive layer adjacent to the transparent conductive layer.

The present invention is to provide a conductive film and a touch panel in which the conductivity of the transparent conductive layer is good 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.

In the present invention [1], 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, and the refractive index of the intermediate layer is 1.60 or more and 1.70 or less, The conductive film in which the intermediate layer contains inorganic particle components containing silica particles and inorganic particles other than silica particles, and the content ratio of the inorganic particle components in the intermediate layer is 40.0% by mass or more and 66.0% by mass or less. are doing

This invention [2] includes the conductive film described in [1], wherein the intermediate layer has a thickness of 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% by mass or more and 60.0% by mass or less.

In the present invention [4], 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], wherein both the transparent conductive layer and the metal layer are patterned.

The present invention [8] includes the conductive film according to any one of [1] to [7], which is wound in a roll shape.

The present 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. Moreover, visibility of the wiring pattern of a transparent conductive layer can be suppressed. In addition, the conductivity of the transparent conductive layer is good.

1 shows a cross-sectional side view of an embodiment of a conductive film of the present invention.
FIG. 2 shows a cross-sectional side view of a patterned conductive film formed from the conductive film shown in FIG. 1 .
Fig. 3 shows a cross-sectional side view of another embodiment (form without a hard coat layer) of the conductive film of the present invention.
Fig. 4 shows a cross-sectional side view of another embodiment (type not provided with a hard coat layer) of the patterned conductive film of the present invention.

EMBODIMENT OF THE INVENTION Embodiment of this invention is described below, referring drawings. In Fig. 1, the vertical direction of the paper is the vertical direction (thickness direction, first direction), the upper side of the paper is the upper side (one side of the first direction, one side of the thickness direction), and the lower side of the paper is the lower side (the other side of the thickness direction, the second direction). 1 direction and the other side). In addition, the left-right direction of the paper is the left-right direction (direction orthogonal to the second direction, the width direction, and the vertical direction), the left side of the paper is the left (one side of the second direction), and the right side of the paper is the right (the other side of the second direction). . In addition, the paper thickness direction is the front-back direction (the third direction, the direction orthogonal to both the vertical direction and the left-right direction), the front side of the paper sheet is the front side (one side of the third direction), and the back side of the paper sheet is the rear side (the other side of the third direction) side) is. Other drawings are the same as those in FIG. 1 .

<First Embodiment>

1. Conductive film

As shown in FIG. 1 , for example, the conductive film 1 as the first embodiment of the conductive film of the present invention has a film shape (including 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 (the same applies hereinafter).

The conductive film 1 is, for example, a part of a base material for a touch panel or the like with which an image display device is equipped, 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 or the like, and does not include an image display element such as an LCD module, and includes a transparent substrate 2, a hard coat layer 3, and an intermediate layer 4 described later. ), the transparent conductive layer 5, and the metal layer 6, and distributed as a single component, it is 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 an upper surface of the hard coat layer 3. It has 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 substrate 2, a hard coat layer 3, an intermediate layer 4, a transparent conductive layer 5, and a metal layer 6. Hereinafter, each layer is described in detail.

2. Transparent substrate

The transparent substrate 2 is a substrate that secures the mechanical strength of the conductive film 1 . The transparent substrate 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. Examples of the material of the polymer film include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate; (meth)acrylic resins such as polymethacrylate (acrylic resins and/or methacrylic resins), for example, olefin resins such as polyethylene, polypropylene, cycloolefin polymers (COPs), for example, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, Polyamide resin, polyimide resin, cellulose resin, polystyrene resin, norbornene resin, etc. are mentioned. A polymer film can be used individually or in combination of 2 or more types.

From the viewpoints 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 base material 2 is, for example, 2 µm or more, preferably 20 µm or more, from the viewpoint of mechanical strength, scratch resistance, and spot characteristics when the conductive film 1 is used as a film for a touch panel. And, for example, 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).

Moreover, an easily bonding layer, an adhesive layer, a separator, etc. may be formed in the upper surface and/or lower surface of the transparent base material 2 as needed.

3. Hard coat layer

The hard coat layer 3 is used to protect the surface of the conductive film 1 (i.e., the upper surface of the metal layer 6) from being easily scratched when a plurality of conductive films 1 are laminated. It is a layer. Moreover, it can also be set as an anti-blocking layer for providing blocking resistance to the conductive film 1.

The hard coat layer 3 has a film shape, and is disposed, 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 from a hard-coat composition, for example. A hard-coat composition contains a resin component, Preferably it consists of a resin component.

Examples of the resin component include curable resins and thermoplastic resins (eg, polyolefin resins), and curable resins are preferred.

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

Examples of the active energy ray-curable resin include a polymer having a functional group having a polymerizable carbon-carbon double bond in the molecule. As such a functional group, a vinyl group, a (meth)acryloyl group (methacryloyl group and/or acryloyl group), etc. are mentioned, for example.

Specifically as an active energy ray-curable resin, (meth)acrylic-type ultraviolet curable resins, such as urethane acrylate and epoxy acrylate, are mentioned, for example.

Moreover, as curable resin other than active energy ray-curable resin, a urethane resin, a melamine resin, an alkyd resin, a siloxane type polymer, an organosilane condensate etc. are mentioned, for example.

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

Resin additives, such as a polymerization initiator, may be contained in the resin component.

As a polymerization initiator, radical polymerization initiators, such as a photoinitiator and a thermal polymerization initiator, are mentioned, for example. These polymerization initiators can be used alone or in combination of two or more.

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-amino ketone compounds and the like are exemplified.

As a thermal polymerization initiator, an organic peroxide, an azo compound, etc. are mentioned, for example.

The hard coat composition may contain particles.

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

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

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. to be. 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 middle layer 4 improves the adhesion between the metal layer 6 side of the conductive film 1 (particularly the transparent conductive layer 5) and the transparent base material 2 side (particularly the hard coat layer 3 layer). , It is an adhesive layer for suppressing peeling between layers inside the conductive film (1). In addition, in order to ensure the excellent transparency of the conductive film 1 while suppressing visibility of the wiring pattern of the transparent conductive layer 5, optical adjustment for adjusting the optical properties (eg refractive index) of the conductive film 1 It is also a layer.

The intermediate layer 4 has a film shape, and is disposed, 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 middle 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 of 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, more preferably a resin layer composed of an inorganic particle component and a resin component.

As a resin component, resin similar to resin used with a hard-coat composition is mentioned, for example. Resin can be used alone or in combination of two or more. A curable resin is preferred, and an active energy ray curable resin is more preferred.

The content of the resin component is, for example, 34.0% by mass or more, preferably 40.0% by mass or more, and, for example, 60.0% by mass or less, preferably 50.0% by 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).

As the second inorganic particles, preferably, inorganic particles having a higher refractive index than silica particles (for example, a refractive index of 2.00 or more) are exemplified. Specifically, zirconium oxide particles, titanium oxide particles, zinc oxide particles, etc. Metal oxide particles are exemplified. From the viewpoint of adhesion and suppression of visibility of the wiring pattern, preferably, zirconium oxide particles are used. These second inorganic particles can be used alone or in combination of two or more.

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, still more preferably contains silica particles and zirconium oxide particles. made up of

The silica particle content 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, More preferably, it is 15.0 mass % or less. If the content ratio of the silica particles is within the above range, the adhesiveness can be further improved. Moreover, 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, and more preferably 95.0 mass% or less. When 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 within 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 the particles represents the average particle diameter (D ₅₀ ) of the particle size distribution on a volume basis. For example, a solution in which particles are dispersed in water can be measured by an optical diffraction/scattering method.

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 (and furthermore, the middle layer 4). It is preferably 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 rate of an inorganic particle component is less than the said lower limit, the wiring pattern of the transparent conductive layer 5 will become easy to visually recognize.

The refractive index of the intermediate layer 4 is 1.60 or more and 1.70 or less. It is preferably 1.62 or more, and preferably 1.68 or less. When 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.

A refractive index can be measured on condition of wavelength 589nm with the Abbe refractometer, for example.

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. When 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 a cross section of the conductive film 1 using a transmission electron microscope, for example.

5. Transparent conductive layer

The transparent conductive layer 5 is formed in a wiring pattern (patterning transparent conductive layer 5A to be described later) in a later step, and, for example, a wiring pattern in a touch input region of a touch panel (e.g., electrode wiring) ) is a transparent conductive layer for forming.

The intermediate layer 4 has a film shape, and is disposed so as to contact the upper surface of the intermediate layer 4 on the entire upper surface of the intermediate layer 4, for example. 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 selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W, for example. A metal oxide containing at least one type of metal is exemplified. The metal oxide may be further doped with a metal atom shown in the above group as needed.

Examples of the material of the transparent conductive layer 5 include indium-containing oxides such as indium tin composite oxide (ITO), antimony-containing oxides such as antimony tin composite oxide (ATO), and the like, preferably Preferably an indium-containing oxide, more preferably ITO.

When ITO is used as the material of the transparent conductive layer 5, the content of tin oxide (SnO ₂ ) 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 ). It is preferably 3% by mass or more, and, for example, 15% by mass or less, preferably 13% by mass or less. By making content of tin oxide more than the said lower limit, the durability of an ITO layer can be further improved. By making content of tin oxide below the said upper limit, the crystal inversion of an ITO layer can be made easy, and transparency and stability of specific resistance can be improved.

"ITO" in this specification should just be a complex oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of additional components include metal elements other than In and Sn, and specific examples include Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. , Fe, Pb, Ni, Nb, Cr, Ga and the like.

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

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

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, more specifically 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.

When 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, 15 It can be judged by measuring the resistance between the terminals between the millimeters. In this specification, when the resistance between terminals between 15 mm is 10 kΩ or less after immersion in hydrochloric acid (20°C, concentration: 5% by mass), water washing, and drying, the ITO layer is assumed to be crystalline.

The surface resistance value of the transparent conductive layer 5 (particularly, 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, it is 10 Ω/□ or more. The surface resistance value can be measured by the 4-terminal method in accordance with JIS K 7194 (1994), for example.

6. Metal layer

The metal layer 6 is formed in a wiring pattern (patterning metal layer 6A to be described later) in a later step, and, for example, wiring at the outer edge (outer periphery) of the touch input region of the touch panel. It is a conductive metal layer for forming a pattern (for example, winding wiring).

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

As a material of the metal layer 6, metal, such as copper, nickel, chromium, iron, titanium, or alloys thereof, is mentioned, for example. From the viewpoint of conductivity and the like, copper is preferably used.

In the case where the metal layer 6 is a material that is easily oxidized, such as copper, 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 having copper oxide on a part or all of its surface.

The thickness of the metal layer 6 is 100 nm or more and 400 nm or less. It is preferably 150 nm or more, and preferably 300 nm or less. When the thickness of the metal layer 6 is less than the said lower limit, the surface resistance value of the metal layer 6 will become high and electrical conductivity will fall. Therefore, it becomes difficult to form a narrow and long wiring pattern (circling wiring of the frame part) corresponding to the increase in the size of the touch panel. Moreover, when the thickness of the metal layer 6 exceeds the said upper limit, the improvement of electrical conductivity is saturated, and it becomes disadvantageous in terms of cost. Moreover, thinning of a frame part becomes difficult.

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

7. Manufacturing method of conductive film

To manufacture the conductive film 1, for example, in a roll-to-roll process, on one side of the transparent substrate 2, the hard coat layer 3, the intermediate layer 4, the transparent conductive layer 5 and the metal layer (6) is formed in order. That is, the hard coat layer 3 is formed on the upper surface of the transparent substrate 2 while sending out the long transparent substrate 2 in the longitudinal direction from the delivery roll and conveying it downstream in the conveying direction, and then, the hard coat layer 3 ) is formed on the upper surface of the intermediate layer (4), then the transparent conductive layer (5) is formed on the upper surface of the intermediate layer (4), and then the metal layer (6) is formed on the upper surface of the transparent conductive layer (5), The conductive film 1 is wound up with a winding roll. Hereinafter, it describes in detail.

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

Then, as needed, 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 sputtering, corona discharge, flame, ultraviolet irradiation, or electron beam irradiation, for example. , etching treatment such as chemical conversion or oxidation, or undercoating treatment can be performed. In addition, the transparent substrate 2 can be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like.

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 obtained by diluting the hard coat composition with a solvent is prepared, and then the coating liquid is applied to the upper surface of the transparent substrate 2 and dried.

Examples of the solvent include organic solvents and aqueous solvents (specifically, water), and preferably organic solvents. Examples of the organic solvent include alcohol compounds such as methanol, ethanol and isopropyl alcohol; ketone compounds such as acetone, methyl ethyl ketone and methyl isobutyl ketone; eg 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 alone or in combination of two or more. Preferably, ester compounds and ether compounds are used.

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

The drying temperature is, for example, 50°C or higher, preferably 60°C or higher, and, 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, and, for example, 60 minutes or less, preferably 20 minutes or less.

Then, when a hard-coat composition contains active energy ray-curable resin, active energy ray-curable resin is hardened by irradiating an active energy ray after drying of a coating liquid.

Moreover, when a hard-coat composition contains a thermosetting resin, the thermosetting resin can be thermosetted with drying of a solvent by this drying process.

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

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

After that, 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.

Moreover, when the intermediate|middle layer composition contains a thermosetting resin, the thermosetting resin can be thermosetted with drying of a solvent by 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.

As a dry method, a vacuum deposition method, a sputtering method, an ion plating method, etc. are mentioned, for example. A sputtering method is preferred. By this method, the transparent conductive layer 5 which is a thin film and has a uniform thickness can be formed.

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

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

When employing the sputtering method, as a target material, the above-mentioned metal oxide which comprises the transparent conductive layer 5 etc. are mentioned, Preferably ITO is mentioned. The tin oxide concentration of ITO is, for example, 0.5% by mass or more, preferably 3% by mass or more, and, for example, 15% by mass or less, preferably from the viewpoint of durability of the ITO layer, crystallization, etc. It is 13 mass % or less.

As a gas, an inert gas, such as Ar, is mentioned, for example. Moreover, reactive gases, such as oxygen gas, can be used together as needed. In the case of 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% or more and 5 flow% 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 preferably 0.1 Pa or more and 0.7 Pa or less, from the viewpoint of suppressing a decrease in sputtering rate, discharge stability, and the like.

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

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.

Examples of the dry method include the same ones as those described above in the formation of the transparent conductive layer 5, and preferably a sputtering method. With this method, even if it is a thick film, the metal layer 6 having a uniform thickness can be formed.

The conditions of the sputtering method in the metal layer 6 are also the same as the conditions illustrated in the formation of the transparent conductive layer 5.

Moreover, as a target material, the above-mentioned metal etc. which comprise the metal layer 6 are mentioned, Preferably copper is mentioned.

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

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

In addition, a crystal inversion process can be performed on the transparent conductive layer 5 of the conductive film 1 as needed. The crystallization inversion treatment may be performed on the obtained conductive film (1), or the conductive film (1) before laminating the metal layer (6) (intermediate laminate, ie, transparent substrate (2)/hard coat layer (3) ) / intermediate layer (4) / laminate of transparent conductive layer (5)).

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

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

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 setting the heating temperature within the above range, crystal inversion 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, and 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.

Moreover, in the said process, you may wind it around a winding roll for every formation of each layer. Moreover, it may be carried out continuously without winding until formation of the hard coat layer 3, the intermediate layer 4, the transparent conductive layer 5, and the metal layer 6, and may be wound around a winding roll after the formation of the metal layer 6.

In addition, if necessary, the transparent conductive layer 5 and/or the metal layer 6 may be patterned into a stripe-like wiring pattern by using a known etching technique before or after the crystal inversion process.

When the transparent conductive layer 5 and the metal layer 6 are etched, these may be etched simultaneously or separately, but preferably the transparent conductive layer 5 and the metal layer 6 are etched in separate patterns. From the standpoint of being able to form reliably, these are etched separately.

For example, first, the metal layer 6 ( In particular, the central portion in plan view) is removed by etching. Then, the transparent conductive layer 5 exposed from the metal layer 6 (particularly, the central portion in plan view) is etched so that a desired wiring pattern (for example, a wiring pattern in a touch input region) is formed. Remove.

Thus, 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 patterning transparent conductive layer 5A, and the patterning metal layer ( A patterned conductive film 1A provided with 6A) is obtained.

In addition, the patterning metal layer 6A forms a frame portion having a frame shape in plan view, and the patterning transparent conductive layer 5A forms a predetermined wiring pattern in the patterning metal layer 6A.

8. Touch panel

The conductive film 1 is used, for example, for a base material for a touch panel provided in an image display device. As a form of a touch panel, various methods, such as a capacitance type and a resistive film type, are mentioned, for example, It is used especially for the capacitance type touch panel. Specifically, for example, the patterned conductive film 1A is used as a touch panel by arranging it on a protective substrate such as protective glass.

In addition, the conductive film 1 may be, for example, an electrophoretic method, a twist ball method, a thermal rewritable method, an optical recording liquid crystal method, a polymer dispersed liquid crystal method, a guest/host liquid crystal method, a toner display method, a black It can also be used suitably also for flexible display elements, such as a mist system and a field deposition system.

9. Action effect

The conductive film 1 includes a transparent substrate 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. 400 nm or less. For this reason, the conductivity (low surface resistance value) of the metal layer 6 can be made favorable. As a result, it is possible to reliably form a narrow and elongated wiring pattern (circumferential wiring) in the frame portion (end portion) of the touch panel. Therefore, even if the touch panel is enlarged, the frame size can be reduced.

Further, the refractive index of the middle layer 4 is 1.60 or more and 1.70 or less, the middle layer 4 contains inorganic particle components containing silica particles and second inorganic particles, and the middle layer 4 contains inorganic particle components 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 (ie, low surface resistance value), the adhesion between the metal layer 6 and the transparent substrate 2 is good. In particular, since the adhesiveness of the interface between the transparent conductive layer 5 and the intermediate layer 4 is good and cohesive failure between them can be suppressed, separation between the metal layer 6 and the transparent substrate 2 can be suppressed. . In addition, when the transparent conductive layer 5 is formed in a wiring pattern (for example, a pattern in a touch input region of a touch panel; patterning transparent conductive layer 5A), visibility of the wiring pattern can be suppressed. . In addition, since the conductivity of the transparent conductive layer 5 is good, excellent touch response is provided even when the touch panel is enlarged.

Further, conventionally, when an adhesion layer is formed between the transparent conductive layer 5 and the transparent substrate 2, 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, crystallization of the transparent conductive layer 5 and, consequently, resistance reduction are affected, crystallization of the transparent conductive layer is inhibited, and the surface resistance value is reduced. There are cases in which this does not happen.

On the other hand, in the conductive film 1 of the present invention, the intermediate layer 4 having the specific configuration described above is disposed between the hard coat layer 3 and the transparent conductive layer 5. Therefore, surface resistance value can be reduced, without improving these adhesiveness, suppressing visibility of a wiring pattern, and also impairing the crystallization of the transparent conductive layer 5 by extension.

<Example of modification>

In the embodiment shown in FIG. 1 , the conductive film 1 is provided with the hard coat layer 3 . For example, as shown in FIG. 3 , the conductive film 1 is the hard coat layer 3 do not have to be provided. That is, the conductive film 1 shown in FIG. 3 consists of a transparent substrate 2, an intermediate layer 4, a transparent conductive layer 5, and a metal layer 6.

In addition, in the embodiment shown in FIG. 2 , the patterning conductive film 1A is equipped with the hard coat layer 3, but as shown in FIG. 4, for example, the conductive film 1 is the hard coat layer. (3) is not required. That is, the conductive film 1 shown in FIG. 4 consists of a transparent substrate 2, an intermediate layer 4, a patterned transparent conductive layer 5A, and a patterned metal layer 6A.

Also in this embodiment, the same effect as the embodiment shown in Figs. 1 and 2 is exhibited. Preferably, the embodiment shown in FIGS. 1 and 3 is mentioned from a viewpoint of abrasion resistance.

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

Also in this embodiment, the same effect as the embodiment shown in Figs. 1 and 2 is exhibited.

Example

Examples and comparative examples are shown below to explain the present invention more specifically. In addition, this invention is not limited at all to an Example and a comparative example. Specific numerical values such as the blending ratio (content ratio), physical property values, and parameters used in the following description are the blending ratios (content ratio) corresponding to those described in the above "mode for carrying out the invention", It can be replaced with the upper limit value (numerical value defined as "below" or "less than") or lower limit value (numerical value defined as "above" or "exceeding") of the corresponding description, such as physical property value or parameter.

(Example 1)

As a long transparent substrate, a 100 µm-thick cycloolefin polymer film (COP film, manufactured by Zeon Corporation, "Zeonoa ZF16") 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 photoinitiator ("Irgacure184", manufactured by BASF), and 160 parts by mass of ethyl acetate. A hard coat composition solution was applied to the upper surface of the COP film, dried at 80°C for 1 minute, and irradiated with ultraviolet rays. Thus, a hard coat layer having 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 (manufactured by JSR Corporation, "KZ6954"). An intermediate layer composition solution was applied to the upper surface of the hard coat layer, dried at 60°C for 1 minute, and irradiated with ultraviolet rays. Thus, an intermediate layer having 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 (manufactured by JSR Corporation, "KZ6954") 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 of 10 nm) and 81 mass % of zirconium oxide particles (average particle diameter of 25 nm).

Then, the laminate of the COP film/hard coat layer/intermediate layer was put into a winding-type sputtering apparatus to form an ITO layer (amorphous) having a thickness of 30 nm on the upper surface of the interlayer. Specifically, using an ITO target made of a sintered body of 97 mass% indium oxide and 3 mass% tin oxide in a vacuum atmosphere of 0.4 Pa atmospheric pressure into which 98% argon gas and 2% oxygen gas were introduced, for the intermediate layer Sputtering was performed.

Next, the laminate of COP film/hard coat layer/intermediate layer/ITO layer (amorphous) was put into a winding-type sputtering apparatus to form a copper layer having a thickness of 200 nm 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 at an atmospheric pressure of 0.4 Pa in which argon gas was introduced.

Thus, the roll-shaped conductive film of Example 1 was produced.

(Examples 2 to 4)

In the formation of 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 Corporation so that the formulation of the intermediate layer was the formulation 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 JSR Offstar KZ series, Offstar Z series, and "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 ("KZ6954" 25% by mass "KZ6956" 75% by mass) manufactured by JSR Co., Ltd. were prepared so that the formulation of the intermediate layer was the formulation shown in Table 1 and the refractive index was 1.60. 100 parts by mass and 2 kinds 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 Kayaku Co., Ltd.) are mixed to form an inorganic particle resin solution Except having prepared, it carried out similarly to Example 1, and manufactured the conductive film.

(Example 6)

In the formation of the middle layer, 66 parts by mass of "Obstar Z7414" manufactured by JSR Corporation and 34 parts by mass "RA017" manufactured by Arakawa Chemical Industry Co., Ltd. A conductive film was produced in the same manner as in Example 1 except that the mixture was mixed to prepare an inorganic particle resin solution.

(Comparative Examples 1 to 5)

In the formation of the intermediate layer, the Offstar KZ series ("KZ6953", "KZ6954", "KZ6956") or the Offstar Z series ("Z7549") manufactured by JSR Co. A conductive film was produced in the same manner as in Example 1 except that the mixture was properly mixed and an inorganic particle resin solution was prepared.

(Comparative Example 6)

A conductive film was produced 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)

A layer with a thickness of less than 1.0 µm was measured by observing a cross section of the conductive film using a transmission electron microscope (manufactured by Hitachi, Ltd., "H-7650"). A layer having a thickness of 1.0 μm or more was measured using a film 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 Co., Ltd.).

(Adhesion)

On the surface of the copper layer of the conductive film obtained in each Example and each Comparative Example, a cutting surface was cut in a checkerboard pattern using a cutter knife so that 100 square grids (10 rows x 10 columns) of 1 mm square were formed. formed. Next, after sticking adhesive tape (product name "Cellotape (registered trademark) No. 252" by Sekisui Chemical Industry Co., Ltd.) on the copper layer surface in which the cut surface was formed, the peeling process was repeated twice. The surface of the copper layer at this time was visually observed, and adhesiveness was evaluated as follows. The results are shown in Table 1.

5: Peeling of the copper layer was not observed at all (peeling area is less than 1%)

4: It was the extent that a chipping was seen around the cut surface of a crosscut (peeling area 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 are obtained for the adhesion of the copper layer even when the ITO layer is a crystalline layer.

(Visibility of wiring pattern)

The roll-shaped conductive films obtained in each Example and each Comparative Example were cut into 10 cm × 10 cm, a dry film resist having a predetermined pattern was disposed on the metal layer of the conductive film, and only the metal layer was etched, and then the resist was removed did Thus, a metal layer corresponding to the circumferential wiring of the frame was patterned only on the circumferential edge.

Next, a dry film resist having a predetermined pattern was disposed on the central ITO layer when viewed from a plan view excluding the frame of the conductive film, and only the ITO layer was etched, and then the resist was removed. Thus, an ITO layer corresponding to the wiring pattern was patterned at the center in plan view (see Fig. 2).

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

A case where no wiring pattern was confirmed was evaluated as ○, a case where a slight wiring pattern was confirmed was evaluated as Δ, and a case where the wiring pattern was clearly confirmed was 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 (a laminate of COP film/hard coat layer/intermediate layer/ITO layer (amorphous)) immediately before forming the copper layer was put into an air circulation oven in a roll-to-roll manner. Then, heat treatment was performed at 140°C for 60 minutes to crystallize the ITO layer. In this way, a sample for measuring the surface resistance value (a laminate of COP film/hard coat layer/intermediate layer/crystalline ITO layer) was obtained.

The surface resistivity of the crystalline ITO layer of each sample was measured by the 4-terminal method according to JIS K 7194 (1994). The results are shown in Table 1.

(surface resistance value of copper layer)

As a result of measuring the surface resistance value of the copper layer of the roll-shaped conductive film obtained in each Example and each Comparative Example by the 4-probe method, the surface resistance value (0.6 Ω/□) of the conductive film of Comparative Example 6 was obtained in each Example. and the surface resistance value (0.1 Ω/□) of the conductive films of Comparative Examples 1 to 5.

In addition, although the said invention was provided as embodiment of an illustration of this invention, this is only a mere illustration and must not interpret it limitedly. Modifications of the present invention that are clear to those skilled in the art are included in the claims described later.

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

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 an inorganic particle component containing silica particles and inorganic particles other than silica particles,
A conductive film characterized in that a 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. 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 a content ratio of the inorganic particle component in the intermediate layer is 50.0% by mass or more and 60.0% by mass or less. According to claim 1,
The 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 other than the silica particles are zirconium oxide. According to claim 1,
The 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 by being wound in a roll shape. A touch panel comprising the conductive film according to claim 1 .

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