TWI694004B - Transparent conductive film - Google Patents

Abstract

The present invention provides a laminated body for forming a transparent conductive layer and a transparent conductive film using the same. The laminated body for forming a transparent conductive layer has a low refractive index layer with excellent etching resistance, is capable of stably making invisible a pattern shape of the transparent conductive layer, and has excellent adhesion to the transparent conductive layer and the like.

A laminated body for forming a transparent conductive layer and the like having an optical adjustment layer on at least one of the surfaces of a substrate film, wherein the optical adjustment layer is formed by laminating a high refractive index layer having a refractive index of 1.6 or more and a low refractive index layer having a refractive index of 1.45 or less in this order from the substrate film side, the low refractive index layer containing silica microparticles, and, on the exposed surface side of the low refractive index layer, the proportion of space where there are no silica microparticles being 15% or more.

Description

Transparent conductive film

The present invention relates to a laminate for forming a transparent conductive layer and a transparent conductive film.

In particular, it relates to a laminate for forming a transparent conductive layer, which has excellent etching resistance in a low refractive index layer, can stably not visualize the pattern shape of a transparent conductive layer, and has excellent adhesion to a transparent conductive layer, etc. and Use its transparent conductive film.

Conventionally, a touch panel that inputs information by directly contacting an image display unit is configured by disposing a light-transmitting input device on a display.

As a representative form of the touch panel, there is a low-resistance film-type touch panel in which two transparent electrode substrates are arranged with a gap in which individual transparent electrode layers face each other and arranged, or a transparent electrode film and a An electrostatic capacitance type touch panel that changes the electrostatic capacitance generated between fingers.

Among them, as an electrostatic capacitance type touch panel, as a sensor for detecting the contact position of a finger, there are roughly divided into transparent guides A glass sensor formed by laminating an electric layer on a glass substrate, and a thin film sensor formed by laminating a transparent conductive layer on a transparent plastic film substrate.

In particular, in a thin film sensor, two transparent conductive films provided with a transparent conductive layer patterned into a linear shape are arranged in such a manner that the individual patterns cross each other to form a grid-like pattern.

However, in the case of such a patterned transparent conductive layer, the boundary between the patterned portion and the non-patterned portion becomes easy to distinguish, and the problem of deterioration in the appearance of the capacitive touch panel is found.

Therefore, a technique useful for solving this problem is disclosed (for example, refer to Patent Documents 1 and 2).

That is, Patent Document 1 discloses a laminated film for optics, which is a laminated film provided with a resin layer on at least one side of a polyester film, characterized in that the resin layer contains at least silica particles (B ) And acrylic resin (D), the silica particles are particles having hollow particles and/or pores, and the number average particle diameter of the silica particles is 30 nm or more and 120 nm or less, the acrylic resin (D) is used A resin composed of the (meth)acrylate monomer (d-1) represented by the following general formula (1) and the (meth)acrylate monomer (d-2) represented by the following general formula (2) The minimum reflectance of the resin layer side of the laminated film is 2.0% or less.

(In the general formula (1), the R ¹ group represents a hydrogen atom or a methyl group, and in the general formula (1), n represents an integer of 9 or more and 34 or less).

(In general formula (2), the R ¹ group represents a hydrogen atom or a methyl group, and the R ² group represents a functional group containing two or more saturated carbocycles).

In addition, Patent Document 2 discloses a method for manufacturing a transparent conductive film, which is a transparent film substrate on one side or both sides through at least one undercoat layer, has a transparent conductor layer, and the transparent conductor layer has A patterned method for manufacturing a transparent conductive film with at least one undercoat layer in a non-patterned portion that does not have a transparent conductor layer, characterized by having one or both sides on a transparent film substrate, A step of forming an undercoat layer formed of a transparent thin-film substrate by an organic substance, a step of forming a transparent conductor layer on the undercoat layer by sputtering, and a step of patterning by etching the transparent conductor layer.

In addition, it is described that the above-mentioned undercoat layer is composed of two layers, and becomes an SiO ₂ film formed by coating the topmost undercoat layer with silica sol.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2013-52676 (Scope of Patent Application)

[Patent Document 2] Japanese Patent Laid-Open No. 2011-142089 (Application for Patent Scope)

However, in the laminated film for optics disclosed in Patent Document 1, when the transparent conductive layer is patterned by etching, it is found that the resin layer forming the transparent conductive layer is easily eroded by the etching solution, and thus is not stable See the problem that the pattern shape of the transparent conductive layer becomes difficult.

More specifically, in recent years, with the increase in the production of smartphones, etc., the etching process is required to be accelerated, especially in the final step of the etching process, which is an alkali process for removing residual photoresist, for example, heating to 40 In the case of 5% by weight of sodium hydroxide aqueous solution at ℃.

When such a strict alkali treatment is performed, in the optical laminate film disclosed in Patent Document 1, the silicon dioxide particles in the resin layer are easily dissolved or detached, and as a result, a transparent conductive layer that is stably invisible is found The pattern shape becomes difficult.

Moreover, even in the case of the transparent conductive thin film obtained by the manufacturing method disclosed in Patent Document 2, when strict alkali treatment is performed, the silicon dioxide particles in the SiO ₂ film are easily dissolved or come off, and as a result, It has been found that it is difficult to stably invisible the pattern shape of the transparent conductive layer.

Therefore, in consideration of the above, the inventors of the present invention have found that the outermost surface layer of the laminate for forming a transparent conductive layer has been studied That is, the low refractive index layer contains silicon dioxide, and at the same time, by setting the proportion of voids where no silicon dioxide fine particles are present on the exposed surface side of the low refractive index layer to a value of 15% or more, the above can be solved Problem, and the inventor who completed the present invention.

That is, the object of the present invention is to provide an etching resistance in a low-refractive-index layer that is stable, even under strict etching treatment conditions, and can stably invisible the pattern shape of the transparent conductive layer, and is compatible with the transparent conductive layer, etc. A laminate for forming a transparent conductive layer with excellent adhesion therebetween and a transparent conductive film using the same.

According to the present invention, there is provided a laminate for forming a transparent conductive layer, which is a laminate for forming a transparent conductive layer having an optical adjustment layer on at least one surface of a base film, characterized in that the optical adjustment layer is formed from the base film On the side, a high refractive index layer with a refractive index of 1.6 or more and a low refractive index layer with a refractive index of 1.45 or less are laminated in sequence, and the low refractive index layer contains silica particles, and In the exposed surface side of the low-refractive-index layer, setting the proportion of voids in which silicon dioxide fine particles do not exist to a value of 15% or more can solve the problems described above.

That is, in the case of the laminate for forming a transparent conductive layer of the present invention, the low-refractive-index layer, which is the outermost layer of the transparent conductive layer-forming laminate, contains silicon dioxide fine particles while being exposed at the low-refractive-index layer On the surface side, by setting the proportion of voids where silicon dioxide fine particles do not exist (hereinafter, sometimes referred to as "void ratio") to a value of 15% or more, In the case of etching treatment by alkali treatment, it can be effectively reduced to the rate of change of the porosity of the low refractive index layer before and after it (hereinafter, sometimes referred to as "void change rate").

More specifically, the silicon dioxide fine particles in the low-refractive-index layer can be effectively dissolved or shed by etching treatment (hereinafter, this effect may be referred to as "etching resistance").

As a result, even when etching processing including strict alkali treatment is performed, the specific refractive index required for the low refractive index layer can be effectively maintained, and finally the pattern shape of the transparent conductive layer can be stably invisible.

In addition, even if etching treatment including strict alkali treatment is performed, the rate of change of voids of the low-refractive-index layer before and after it can be effectively reduced, so that the presence of silicon dioxide fine particles can be effectively maintained. Fine irregularities on the surface of the low refractive index layer.

Accordingly, by maintaining the surface free energy on the surface of the low refractive index layer within a specific range, the specific adhesion to the transparent conductive layer and the like required by the low refractive index layer can be obtained.

In addition, it is preferable to set the volume average particle diameter (D50) of the silicon dioxide fine particles to a value in the range of 20 to 70 nm in the laminate for forming the transparent conductive layer of the present invention.

With this configuration, the transparency in the low refractive index layer is not reduced, and a specific refractive index can be obtained.

In addition, in the laminate for forming the transparent conductive layer of the present invention, it is preferable to use silica fine particles as hollow silica fine particles.

With this structure, the fold of silica particles is further reduced Emissivity, even with a small amount of blending, can effectively adjust the refractive index of the low refractive index layer to a specific refractive index.

In addition, in the laminate for forming the transparent conductive layer of the present invention, it is preferable that the silicon dioxide fine particles are reactive silicon dioxide fine particles.

With such a configuration, since the silica particles can be firmly fixed to the low refractive index layer, the etching resistance can be improved more effectively.

Further, in the laminate for forming the transparent conductive layer of the present invention, it is preferable that the matrix portion of the low refractive index layer contains a cured product of active energy ray-curable resin.

With this configuration, the silicon dioxide fine particles in the low refractive index layer can be more effectively protected, and the etching resistance can be more effectively improved.

In addition, in the laminate for forming the transparent conductive layer of the present invention, it is preferable that the active energy ray-curable resin contains a water-repellent resin.

With such a configuration, since the silicon dioxide fine particles in the low refractive index layer can be effectively protected, an additional layer can be further effectively improved in etching resistance.

In addition, in the laminate for forming the transparent conductive layer of the present invention, it is preferable to set the free energy on the surface of the low refractive index layer to a value of 37 mN/m or more.

With such a configuration, not only the etching resistance is improved, but also the specific adhesion to the transparent conductive layer and the like required by the low refractive index layer can be obtained more effectively.

Moreover, in the laminate for forming the transparent conductive layer of the present invention, it is preferable to set the film thickness of the low refractive index layer in the range of 20 to 80 nm Value.

With such a configuration, sufficient etching resistance can be obtained, whereby even after strict etching conditions, the pattern shape of the transparent conductive layer can be more invisible, and further, by adjusting the blending of silicon dioxide fine particles Volume, the porosity or surface roughness can be easily adjusted.

Moreover, another aspect of the present invention is a transparent conductive film, which is a transparent conductive film formed by sequentially laminating an optical adjustment layer and a transparent conductive layer on the surface of at least one side of a substrate film, which The characteristic is that the optical adjustment layer is formed by sequentially laminating a high-refractive-index layer with a refractive index of 1.6 or more and a low-refractive-index layer with a refractive index of 1.45 or less from the base film side. It contains silicon dioxide fine particles, and on the exposed surface side of the low refractive index layer, the proportion of voids where the silicon dioxide fine particles are not present is set to a value of 15% or more.

That is, in the case of the transparent conductive film of the present invention, since a specific laminate for forming a transparent conductive layer is used, a pattern of a transparent conductive layer excellent in etching resistance in a low refractive index layer and stably invisible can be obtained Shape, and excellent adhesion to transparent conductive layers.

Furthermore, in the transparent conductive film constituting the present invention, it is preferable that the transparent conductive layer is patterned by etching.

Even in the case of such a configuration, the pattern shape of the transparent conductive layer can be stably invisible due to excellent etching resistance in the low refractive index layer.

1‧‧‧Transparent conductive layer

2‧‧‧Optical adjustment layer

2a‧‧‧Low refractive index layer

2b‧‧‧High refractive index layer

3‧‧‧hard coating

4‧‧‧ Base film

10‧‧‧Laminate for transparent conductive layer formation

20‧‧‧Silica dioxide particles

22‧‧‧Gap

100‧‧‧Transparent conductive film

[FIG. 1] FIG. 1 (a)-(b) are figures for explaining the structure of the laminate for forming a transparent conductive layer of the present invention.

[FIG. 2] FIG. 2 is a diagram for explaining the porosity of the low refractive index layer.

[FIG. 3] FIG. 3 is a diagram for explaining the structure of the transparent conductive film of the present invention.

[FIG. 4] FIGS. 4(a) to (b) are reflected electron images on the exposed surface of the low refractive index layer in Example 1.

[FIG. 5] FIGS. 5(a)-(b) are reflected electron images on the exposed surface of the low refractive index layer in Comparative Example 1. [FIG.

[First Embodiment]

The first embodiment of the present invention is shown in FIG. 1(a), a laminate 10 for forming a transparent conductive layer, which is formed by a transparent conductive layer having an optical adjustment layer 2 on at least one surface of a base film 4 The laminate 10 is characterized in that the optical adjustment layer 2 is from the base film 4 side in the order of a high refractive index layer 2b having a refractive index of 1.6 or more and a low refractive index layer 2a having a refractive index of 1.45 or less Laminated, while the low refractive index layer 2a contains silicon dioxide fine particles, and as shown in FIG. 2, the proportion of the void 22 of the silicon dioxide fine particles 20 will not exist in the exposed surface side of the low refractive index layer 2a (The ratio of voids to the exposed surface area) is set to a value of 15% or more.

In addition, in FIG. 1(a), although the laminate 10 for forming a transparent conductive layer having the state of the hard coat layer 3 is shown as an example on both sides of the base film 4, the hard coat layer 3 may be omitted.

In addition, in FIG. 1(a), the particles in each layer represent silica fine particles or metal oxide particles.

Hereinafter, the first embodiment of the present invention will be specifically described with reference to the drawings.

1. Substrate film

(1) Type

The type of the base film is not particularly limited, and as the base material for optics, a well-known base film can be used.

For example, preferably, polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), polyethylene films, polypropylene films, cellophane (Cellophane), diacetyl cellulose film, triethyl cellulose film, ethyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-acetic acid Vinyl ester copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film , Fluororesin film, polyamide film, acrylic resin film, norbornene-based resin film, cycloolefin resin film and other plastic films.

Among these, from the viewpoint of heat resistance, polyester films, polycarbonate films, polyimide films, and norbornene-based trees are more preferred. Grease film, cycloolefin resin film.

In addition, from the standpoint of transparency, film strength and flexibility, PET film is particularly preferred.

(2) Film thickness

In addition, it is preferable to set the film thickness of the base film to a value in the range of 20 to 200 μm.

This reason is because when the thickness of the base film becomes less than 20 μm , by reducing the strength of the base film, it is not possible to effectively suppress the presence and absence of the transparent conductive layer in the optical adjustment layer Part of the occurrence of distortion during annealing. In addition, when the film thickness of the base film exceeds 200 μm, the optical properties such as the transparency of the base film may deteriorate.

Accordingly, it is more preferable to set the film thickness of the base material film to a value in the range of 30 to 180 μm, and still more preferably to a value in the range of 50 to 150 μm.

Still, the so-called "annealing treatment" means that in order to improve the electrical conductivity of the transparent conductive layer of the transparent conductive film, the transparent conductive layer in a laminated state is heat-treated on the laminate for forming a transparent conductive layer, Perform crystallization treatment.

2. Hard coating

As shown in FIG. 1( a ), it is preferable to provide the hard coat layer 3 on both sides or one side of the base film 4 in the laminate 10 for forming the transparent conductive layer of the present invention.

The reason for this is that, by providing the hard coat layer, in the manufacturing step of the laminate for forming a transparent conductive layer, in addition to imparting scratch resistance to the base film and preventing degradation of optical properties, the base film is wound into In the case of a roll, it is possible to suppress the phenomenon that the base films are bonded to each other (hereinafter, this effect is sometimes referred to as "anti-adhesion").

(1) Material substance

In addition, the hard coat layer is preferably composed of a hardened product of a composition containing silicon dioxide fine particles and active energy ray-curable resin as a material substance.

This reason is because the inclusion of silicon dioxide fine particles and active energy ray-curable resin can provide anti-adhesion, not only to improve the winding properties, but also to the high refractive index layer which is the upper layer of the hard coat layer. Adhesion also enhances it, allowing it to be strongly laminated.

(1)-1 Active energy ray curable resin

In addition, the active energy ray-curable resin used in the formation of the hard coat layer refers to those with energy quanta in electromagnetic waves or charged particle beams, that is, by cross-linking and curing polymerization by irradiating ultraviolet rays or electron beams, etc. Examples of the reactive compound include a photopolymerizable prepolymer and a photopolymerizable monomer.

In addition, the above-mentioned photopolymerizable prepolymers include radical polymerization type and cation polymerization type, and examples of the radical polymerization type photopolymerizable prepolymers include polyester acrylates, epoxy acrylates, and amines. Ethyl acrylate system, polyol acrylate system, etc.

In addition, examples of the polyester acrylate-based prepolymer include esterification of (meth)acrylic acid with the hydroxyl groups of polyester oligomers having hydroxyl groups at both ends obtained by condensation of polycarboxylic acids and polyhydric acids. Or a compound obtained by esterifying the hydroxyl group at the end of the obtained oligomer with (meth)acrylic acid by adding polyalkylene oxide to alkylene oxide.

In addition, examples of the epoxy acrylate-based prepolymer include ethylene oxide (Oxirane) rings of relatively low molecular weight bisphenol-type epoxy resins or novolak-type epoxy resins, by (meth) A compound obtained by esterification of acrylic acid.

Further, examples of the urethane acrylate prepolymer include, for example, a polyurethane oligomer obtained by the reaction of polyether polyol or polyester polyol with polyisocyanate by ( A compound obtained by esterification of meth)acrylic acid.

Furthermore, examples of the polyol acrylate-based prepolymer include compounds obtained by esterifying the hydroxyl group of the polyether polyol with (meth)acrylic acid.

Still, these polymerizable prepolymers may be used alone or in combination of two or more.

In addition, as the cation polymerization type photopolymerizable prepolymer, an epoxy resin is generally used.

Examples of the epoxy resin include compounds obtained by epoxidation of polyphenols such as bisphenol resins and novolac resins with epichlorohydrin, etc., and linear olefin compounds or cyclic olefin compounds with peroxides. Compounds obtained by oxidation.

In addition, examples of the photopolymerizable monomer include 1,4-butane Glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, new Pentanediol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified bicyclic Pentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate , Propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol propane tri (meth) acrylate, ginseng (acryloyloxyethyl) iso Multifunctional acrylates such as cyanurate, propionic acid modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc.

Still, these photopolymerizable monomers may be used alone or in combination of two or more.

(1)-2 photopolymerization initiator

In addition, since the active energy ray-curable resin can be efficiently cured by active energy rays, especially ultraviolet rays, it is also preferable to use a photopolymerization initiator in combination.

As the photopolymerization initiator, examples of the radical polymerization type photopolymerizable prepolymer or photopolymerizable monomer include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin. -n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2- Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1 -Hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, 4-(2-hydroxyethoxy)benzene 2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2 -Methylanthraquinone, 2-ethylanthraquinone, 2-third butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone Ketone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid Ester etc.

In addition, examples of the photopolymerization initiator for the photopolymerizable prepolymer of the cation polymerization type include aromatic onium ions, aromatic oxonium ions (Oxosulfonium) ions, aromatic iodonium ions and other onium ions, and the four Compounds composed of anions such as fluoroborate, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, etc.

Still, these can be used alone or in combination of two or more.

In addition, the blending amount of the photopolymerization initiator is preferably a value in the range of 0.2 to 10 parts by weight relative to 100 parts by weight of the active energy ray-curable resin described above, and more preferably 1 to 5 parts by weight The value within the range of copies.

(1)-3 silica particles

In addition, as the silica fine particles, silica fine particles combined with an organic compound containing a polymerizable unsaturated group, or an organic compound having such a polymerizable unsaturated group in part, usually colloidal dioxide can be used Silicon particles.

In addition, as the silica fine particles combined with an organic compound containing a polymerizable unsaturated group, a silanol group on the surface of the silica fine particles with a volume average particle diameter (D50) of about 0.005 to 1 μm can be cited. It is obtained by reacting an organic compound containing a polymerizable unsaturated group, and the unsaturated group has a functional group that can react with the silanol group.

In addition, examples of the above-mentioned polymerizable unsaturated group include free-radically polymerizable acryl and methacryl groups.

In addition, as the organic compound that does not have a polymerizable unsaturated group, usually colloidal silica fine particles, silica fine particles with a volume average particle size of about 0.005 to 1 μm, preferably about 0.01 to 0.2 μm can be suitably used , Colloidal silica in colloidal state suspended in an organic solvent of alcohol or cellosolve.

In addition, the average particle size of the silica particles can be obtained, for example, by the measurement method of other potentials, and can also be obtained by a laser diffraction scattering type particle size distribution measuring device, and the SEM image can also be Get the foundation.

In addition, the blending amount of the silica fine particles is preferably 5 to 400 parts by weight relative to 100 parts by weight of the active energy ray-curable resin, more preferably 20 to 150 parts by weight, and even more preferably 30 to 100 parts by weight.

(2) Composition for hard coat layer formation

In addition, the hard coat layer is preferably prepared in advance to form a composition for forming a hard coat layer, which is applied as described later. Dry and form by hardening.

If necessary, the composition can be activated by The amount-curing resin, photopolymerization initiator, silica fine particles, and various additional components used as desired are added at specific ratios, respectively, and dissolved or dispersed to prepare them.

In addition, as various additional components, for example, antioxidants, ultraviolet absorbers, (near) infrared absorbers, silane-based coupling agents, light stabilizers, leveling agents, antistatic agents, defoaming agents and the like can be cited.

Examples of the solvent used include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, methanol, ethanol, and propanol. , Butanol and other alcohols, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate, butyl acetate and other esters, ethyl cellosolve, etc. Cellosolve solvents, etc.

The concentration and viscosity of the composition for forming a hard coat layer prepared in this way are not particularly limited as long as they are coatable, and can be appropriately selected according to the situation.

Accordingly, from the viewpoint of easily adjusting the film thickness of the composition for forming a hard coat layer generally obtained in a specific range, it is preferably diluted so that the solid content concentration becomes 0.05 to 10% by weight, and more preferably Dilute by 0.1 to 8% by weight.

(3) Film thickness

In addition, it is preferable to set the film thickness of the hard coat layer to a value in the range of 1 to 15 μm.

This reason is because the thickness of the hard coat layer is less than 1 μm In some cases, the holding function of the thermal shrinkage of the base film by the annealing treatment may become insufficient, and the occurrence of curling may not be suppressed. In addition, when the film thickness of the hard coat layer exceeds 15 μm, exhaust gas may easily occur from the hard coat layer by annealing.

Accordingly, it is more preferable to set the film thickness of the hard coat layer to a value in the range of 1.5 to 10 μm, and still more preferably to a value in the range of 2 to 5 μm.

3. Optical adjustment layer

(1) High refractive index layer

(1)-1 refractive index

The refractive index of the high refractive index layer is preferably set to a value of 1.6 or more.

This reason is because when the refractive index of the high refractive index layer is less than 1.6, there may be no significant difference in refractive index from the low refractive index layer, or the pattern shape of the transparent conductive layer may be easily recognized. In addition, when the refractive index of the high refractive index layer becomes an excessively large value, the film of the high refractive index layer may become brittle.

Accordingly, it is more preferable to set the refractive index of the high refractive index layer to a value in the range of 1.61 to 2, and even more preferably to a value in the range of 1.63 to 1.8.

(1)-2 Material substance

In addition, it is preferable that the high refractive index layer is composed of a cured product of a composition containing metal oxide fine particles as a material substance and an active energy ray curable resin.

This reason is because by including metal oxide fine particles and active energy The linear curable resin makes it easy to adjust the refractive index of the high refractive index layer.

The type of metal oxide preferably includes tantalum oxide, zinc oxide, indium oxide, hafnium oxide, cerium oxide, tin oxide, niobium oxide, indium tin oxide (ITO), antimony tin oxide (ATO), and the like.

In addition, from the viewpoint of achieving a high refractive index without lowering the transparency, particularly preferably at least one kind selected from titanium oxide and zirconium oxide.

Still, these metal oxides may be used alone or in combination of two or more.

In addition, it is preferable that the volume average particle diameter (D50) of the metal oxide fine particles is set to a value in the range of 0.005 μm to 1 μm.

In addition, the volume average particle diameter (D50) of the metal oxide fine particles can be obtained, for example, by a measurement method using a beta potential measurement method, or by a laser diffraction scattering type particle size distribution measurement device, Furthermore, it can be obtained based on the SEM image.

In addition, as the active energy ray-curable resin and the photopolymerization initiator used in the high refractive index layer, those listed in the description of the hard coat layer can be suitably used.

Moreover, as the blending amount of the metal oxide fine particles, it is preferably 20 to 2000 parts by weight, more preferably 80 to 1000 parts by weight, and still more preferably 150 to 400 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin. Copies.

(1)-3 Composition for forming high refractive index layer

In addition, the high refractive index layer is preferably prepared in advance to form a composition for forming a high refractive index layer, coating as described later. Dry and form by hardening.

If necessary, the composition can be added in a specific ratio by adding an active energy ray-curable resin, a photopolymerization initiator, metal oxide fine particles, and various additives used as desired in an appropriate solvent. , Dissolve or disperse to prepare.

The concentration, viscosity, etc. of various additives, solvents, and high-refractive-index layer forming components are the same as those described in the hard coat layer.

(1)-4 film thickness

In addition, it is preferable to set the film thickness of the high refractive index layer to 20 to 130 nm.

This reason is because when the film thickness of the high refractive index layer is less than 20 nm, the film of the high refractive index layer may become brittle and the shape of the layer may not be maintained. In addition, when the film thickness of the high refractive index layer exceeds 130 nm, the pattern shape of the transparent conductive layer may be easily distinguished.

Accordingly, the film thickness of the high refractive index layer is preferably 23 to 120 nm, and more preferably 30 to 110 nm.

(2) Low refractive index layer

(2)-1 refractive index

The low refractive index layer has a refractive index of 1.45 or less as a characteristic.

This reason is because when the refractive index of the low-refractive-index layer exceeds 1.45, a significant difference in refractive index from the high-refractive-index layer may not be obtained, and the pattern shape of the transparent conductive layer may be easily distinguished. In addition, because the refractive index of the low refractive index layer becomes excessively small, the film with the low refractive index layer The situation becomes brittle.

Accordingly, it is more preferable to set the refractive index of the low refractive index layer to a value in the range of 1.3 to 1.44, and still more preferably to a value in the range of 1.35 to 1.43.

(2)-2 Material substance

In addition, in the low refractive index layer of the present invention, as the material substance, it is preferable that the composition for forming a low refractive index layer containing the following components (A) to (B) is photocured.

This reason is because the composition for forming a low-refractive-index layer used for forming the low-refractive-index layer contains the silica particles in a relatively small range relative to the active energy ray-curable resin. It is easy to adjust the porosity to a value of 15% or more, which can effectively improve the etching resistance in the low refractive index layer.

In addition, the active energy ray-curable resin is formed by hardening the matrix portion of the low-refractive-index layer, which effectively protects the silicon dioxide fine particles in the low-refractive-index layer, and can effectively improve the etching resistance.

Hereinafter, each component will be described.

(i) (A) component: active energy ray curable resin

(A) The component-based active energy ray-curable resin.

As the active energy ray-curable resin as the component (A), a photopolymerizable prepolymer or photopolymerization listed in the description of the hard coat layer can be suitably used Combination monomer.

Furthermore, it is preferable that the active energy ray-curable resin contains a water-repellent resin.

This reason is because by containing the water-repellent resin, the silicon dioxide fine particles in the low refractive index layer can be more effectively protected, so that the layer can be further layered and the etching resistance can be effectively improved.

In addition, if it is a water-repellent resin, compared with the (meth)acrylic ultraviolet curable resin which is the main active energy ray curing resin, the refractive index is low, so it is easier to reduce the refractive index of the low refractive index layer to Specific scope.

In addition, as the water-repellent resin, if it is a resin having water-repellent properties, it is not particularly limited, and a conventionally known water-repellent resin can be used.

More specifically, if the water repellent resin monomer is formed on the surface of the resin film with a free energy in the range of 10 to 30 mN/m, it can be suitably used as the water repellent resin in the present invention.

In addition, as specific examples of the water-repellent resin, for example, a silicone resin or, for example, a fluorine resin such as polyvinylidene fluoride, a fluorine-based acrylic resin, and polyvinyl fluoride.

Moreover, among them, it is preferable to use a fluororesin, and particularly preferably a reactive fluoroacrylic resin.

This reason is because if it is a fluororesin, since the silicon dioxide fine particles in the low refractive index layer can be protected more effectively, the etching resistance can be improved more effectively.

Moreover, it is preferable to set the total of (A) component to 100% by weight In the case of, the content of the water-repellent resin is set to a value in the range of 50 to 90% by weight.

This reason is because when the content of the water-repellent resin is less than 50% by weight, it is difficult to effectively protect the silicon dioxide fine particles in the low refractive index layer, which ultimately makes it difficult to improve the etching resistance. In addition, it may be difficult to set the refractive index of the low refractive index layer to a sufficiently low value. In addition, because the content of the water-repellent resin exceeds 90% by weight, the surface free energy of the low-refractive-index layer becomes excessively low, and the specific adhesion to the transparent conductive layer and the like required by the refractive-index layer is obtained. Difficult situation.

According to this, it is more preferable to set the content of the water-repellent resin to a value within the range of 60 to 85% by weight when the total content of the (A) component is set to 100% by weight, and further to 70 to 80% by weight. The value in the range of %.

(ii) (B) Ingredient: silica fine particles

(B) The component is silica fine particles.

Although the type of the silica fine particles is not particularly limited, it is preferable to use hollow silica fine particles.

This reason is because if it is hollow silica particles, since the hollow part inside contains air, the refractive index of the entire silica particles is further reduced, and even a small amount of blending can be more efficient The refractive index of the low refractive index layer is adjusted to a specific refractive index.

Still, the so-called "hollow silica particles" means silica particles with holes inside the particles.

Moreover, it is preferable that the silica fine particles are reactive silica fine particles.

This reason is because if it is reactive silica fine particles, since the silica fine particles can be firmly fixed to the low refractive index layer, the etching resistance can be improved more effectively.

Still, the so-called "reactive silica particles" refers to the combination of silica particles with organic compounds containing polymerizable unsaturated groups, and the silanol groups on the surface of the silica particles can be made by containing polymerizable unsaturated It is obtained by reacting an organic compound of a group, and the unsaturated group has a functional group that can react with the silanol group.

In addition, examples of the above-mentioned polymerizable unsaturated group include a radically polymerizable acryl group and methacryl group.

In addition, it is preferable to set the volume average particle diameter (D50) of the silica fine particles to a value in the range of 20 to 70 nm.

This reason is because by setting the volume average particle diameter (D50) of the silica fine particles to a value within this range, the transparency of the low refractive index layer is not reduced, and a specific refractive index can be obtained.

That is, when the volume average particle diameter (D50) of the silica particles is less than 20 nm, especially in the case of hollow silica particles, it is difficult to sufficiently ensure the cavity inside the particles by the structure, making When the effect of reducing the refractive index of the low refractive index layer becomes insufficient. In addition, when the volume average particle diameter (D50) of the silicon dioxide fine particles exceeds 70 nm, light scattering is likely to occur, and the transparency of the low refractive index layer may be easily reduced.

Accordingly, it is more preferable to set the volume average particle diameter (D50) of the silica particles to a value in the range of 30 to 60 nm, and still more preferably to a value in the range of 40 to 50 nm.

In addition, the volume average particle diameter (D50) of silica fine particles can be obtained, for example, by a beta potential measurement method, or by a laser diffraction scattering type particle size distribution measuring device, and furthermore Obtained based on SEM images.

In addition, it is preferable to set the blending amount of the silica fine particles to a value in the range of 2 to 120 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin containing the water-repellent resin as the component (A).

This reason is because when the blending amount of the silica particles is less than 2 parts by weight, it may be difficult to sufficiently reduce the refractive index of the low refractive index layer, or sufficient surface irregularities may be formed on the surface of the low refractive index layer It becomes difficult, or it becomes difficult to obtain specific adhesion to a transparent conductive layer or the like. In addition, because the blending amount of silicon dioxide fine particles exceeds 120 parts by weight, it may become difficult to adjust the porosity of the low refractive index layer to a value of 15% or more, so etching treatment including strict alkali treatment is performed In some cases, the silica particles in the low-refractive-index layer may dissolve or fall off easily.

Accordingly, it is more preferable to set the blending amount of the silica fine particles to a value in the range of 30 to 110 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin containing the water-repellent resin as the component (A). It is even better to set the value within the range of 50 to 100 parts by weight.

(2)-3 Composition for forming low refractive index layer

In addition, the low-refractive-index layer is a composition for forming a low-refractive-index layer prepared in advance, and is coated as described later. Dry and form by hardening.

If necessary, the composition can be obtained by using the above-mentioned active energy ray-curable resin as component (A), silicon dioxide fine particles as component (B), and a photopolymerization initiator as appropriate in a suitable solvent. The various added components are added in specific ratios to dissolve or disperse them for preparation.

The concentration, viscosity, etc. of various additives, solvents, and low-refractive-index layer forming compositions are the same as those described in the hard coat layer.

(2)-4 film thickness

In addition, it is preferable to set the film thickness of the low refractive index layer to a value in the range of 20 to 80 nm.

This reason is because by setting the film thickness of the low-refractive index layer to a value within this range, sufficient etching resistance can be obtained, whereby the pattern shape of the transparent conductive layer can be more stably invisible, Furthermore, by adjusting the blending amount of silica particles, the porosity or surface roughness can be easily adjusted.

That is, when the film thickness of the low refractive index layer is less than 20 nm, the film of the low refractive index layer may become brittle and the etching resistance may become insufficient. In addition, when the film thickness of the low-refractive-index layer exceeds 80 nm, the pattern shape of the transparent conductive layer may be easily distinguished, and the voids may not be calculated in the definition of voids described below.

According to this, it is more preferable to set the film thickness of the low refractive index layer to 25 to 70 nm The value within the range is even more preferably set within the range of 40 to 60 nm.

(2)-5 void ratio

In the present invention, as shown in FIG. 2, it is characterized in that, on the exposed surface side of the low refractive index layer 2 a, there will be no proportion of voids 22 of silicon dioxide fine particles 20 (ratio of voids relative to the area of the exposed surface) Set at a value above 15%.

This reason is because by setting the porosity to a value of 15% or more, even in the case of performing an etching process including strict alkali treatment, the change in the gap in the low refractive index layer before and after it can be effectively reduced rate.

That is, the etching process can effectively suppress the dissolution or shedding of silicon dioxide fine particles in the low refractive index layer.

More specifically, as shown in FIG. 1(a), when the value of the porosity of the low-refractive-index layer 2a is large, the proportion of the matrix portion composed of resin increases, even in the case of strict alkali treatment The silica particles effectively protect the matrix and can effectively inhibit dissolution or shedding.

In addition, as shown in FIG. 1(b), when the value of the porosity of the low-refractive-index layer 2a ' is small, the proportion of the matrix portion composed of the resin is small. In the case of strict alkali treatment, the dioxide The silicon particles cannot be fully protected by the matrix part, and become easily soluble or fall off.

According to this, by setting the value of the porosity verified by experiment to a value of 15% or more, even if etching treatment including strict alkali treatment is performed, the specificity required for the low refractive index layer can be effectively maintained The refractive index, Finally, the pattern shape of the transparent conductive layer can be stably invisible.

In addition, even if etching treatment including strict alkali treatment is performed, the rate of change of the void in the low-refractive index layer before and after it can be effectively reduced, so that the silica particles can be effectively maintained at Fine irregularities on the surface of the low refractive index layer.

Accordingly, by maintaining the wetting tension on the surface of the low-refractive index layer within a specific range, the specific adhesion force required by the low-refractive index layer for the transparent conductive layer and the like can be obtained.

In addition, when the porosity becomes an excessively large value, it becomes difficult to sufficiently reduce the refractive index of the low-refractive-index layer, or to form sufficient surface irregularities on the surface of the low-refractive-index layer, and obtain a specific density for the transparent conductive layer, etc. The situation becomes difficult.

According to this, in the exposed surface side of the low refractive index layer, the proportion of voids in which silicon dioxide fine particles do not exist, that is, the value of the porosity is preferably in the range of 20 to 70%, and even more preferably It is a value in the range of 22~40%.

In addition, the above-mentioned porosity is obtained by using a scanning electron microscope, for example, to obtain a reflected electron image on the exposed surface side of the low-refractive-index layer. The obtained reflected electron image is preferably binarized using an image processing software and measured for non-existence. The ratio of the voids of silica particles, that is, the void ratio.

Or use a scanning electron microscope to obtain the reflected electron image on the exposed surface side of the low refractive index layer, expand and copy the reflected electron image obtained by copying, and print out the area where the silica particles are present and the gap between the silica particles , Separated with scissors, the porosity can be determined from the weight of the cut paper.

Still, as the definition of the void in the present invention, it means "in a region where no silica particles are present, when drawing the largest circle inscribed in the region, the diameter of the circle is 0.2 μm or more."

In addition, it means that no one silica particle exists in the film thickness direction of the plane position in the exposed surface of the exposed surface regardless of the presence of silica particles.

According to this, for example, even if there is no silicon dioxide fine particles near the surface in the film thickness direction, if there are silicon dioxide fine particles near the bottom surface in the film thickness direction, it is judged that "the presence of silicon dioxide fine particles" is at the plane position.

In addition, it is preferable to immerse the laminate for forming a transparent conductive layer for 5 minutes in a 5 wt% sodium hydroxide aqueous solution heated to 40°C, and perform alkali treatment before and after the increase rate of the porosity in the low refractive index layer ( %), that is, the void increase rate (%) is set to a value below 26%.

This reason is because by setting the void increase rate to a value of 26% or less, the etching resistance to the etching process including strict alkali treatment can be more certainly improved.

That is, when the increase rate of the void becomes a value exceeding 26%, by the etching process, it is effectively suppressed that the silicon dioxide fine particles in the low refractive index layer dissolve or fall out and become difficult. In addition, the lower limit of the void increase rate is preferably 0%. However, when it becomes a small value, it becomes difficult to sufficiently reduce the refractive index of the low refractive index layer, or it becomes difficult to form sufficient surface irregularities on the surface of the low refractive index layer, and a specific adhesion change for the transparent conductive layer and the like is obtained. Difficult situation.

Accordingly, it is more preferable to immerse the laminate for forming a transparent conductive layer for 5 minutes The increase rate (%) of the porosity in the low refractive index layer before and after alkali treatment in the 5 wt% aqueous sodium hydroxide solution heated to 40°C, that is, the void increase rate (%) is set to 10~25 The value within the range of% is even better the value within the range of 19~24%.

(2)-6 surface free energy

In addition, it is preferable to set the surface free energy measured under the condition of 23° C. in accordance with JIS K 6768 of the low refractive index layer to a value of 37 mN/m or more.

This reason is because by setting the surface free energy on the exposed surface of the low refractive index layer to a value within this range, not only the etching resistance is improved, but also the transparency required for the low refractive index layer can be obtained more effectively. Specific adhesion of conductive layers.

That is, when the surface free energy is less than 37 mN/m, it may become difficult to obtain specific adhesion to the transparent conductive layer or the like. In addition, when the surface free energy becomes an excessively large value, the adhesion with the protective film laminated on the transparent conductive layer forming laminate for surface protection becomes excessively enhanced, and the work efficiency is lowered during the peeling step of the protective film Case.

Accordingly, it is more preferable to set the surface free energy measured in accordance with JIS K 6768 on the exposed surface of the low refractive index layer to a value in the range of 40 to 65 mN/m, and even more preferably to 45 to 60 mN/m Within the range of.

4. Manufacturing method of laminated body for forming transparent conductive layer

The laminate for forming a transparent conductive layer of the present invention can be included, for example, by Obtained by the manufacturing method of the following steps (a) to (b).

(a) Step of forming hard coating on both sides of the base film

(b) Step of forming optical adjustment layer on one side of hard coating

In the following, parts that overlap with the contents so far are omitted, and only the different parts are described in detail.

In addition, although the laminate for forming a transparent conductive layer of the present invention does not include the hard coat layer as an essential component, the following description will exemplify the case where the hard coat layer is formed.

(1) Step (a): Step of forming hard coating

On both sides of the substrate film, the above-mentioned hard coat layer forming composition is applied in a conventionally well-known method to form a coating film, and then dried, and the coating film is hardened by irradiation with active energy rays to form Hard coating.

In addition, examples of the coating method of the composition for forming a hard coat layer include a bar coating method, a blade coating method, a roll coating method, a sheet coating method, a die coating method, and a gravure coating method.

In addition, as the drying conditions, it is preferably performed at 60 to 150° C. for about 10 seconds to 10 minutes.

Furthermore, examples of the active energy rays include ultraviolet rays and electron beams.

In addition, examples of the ultraviolet light source include high-pressure mercury lamps, electrodeless lamps, metal halide lamps, and xenon lamps. The irradiation dose is usually 100 to 500 mJ/cm ² .

In addition, as the light source of the electron beam, an electron beam accelerator, etc. may be mentioned. The irradiation dose is usually preferably 150 to 350 kV.

(2) Step (b): Step of forming the optical adjustment layer

Secondly, a high refractive index layer is formed on the formed hard coating layer (directly on the substrate film without forming a hard coating layer).

That is, the high refractive index layer is formed in the same way as the hard coat layer formed on the substrate film, which can be applied by coating. The above composition for forming a high refractive index layer is dried and irradiated with active energy rays to be hardened to form.

Secondly, a low refractive index layer is further formed on the formed high refractive index layer.

That is, the low-refractive-index layer is formed in the same way as the hard coat layer formed on the substrate film, and can be applied by coating. The composition for forming the low-refractive-index layer described above is dried and simultaneously irradiated with active energy rays to be hardened to form.

[Second Embodiment]

The second embodiment of the present invention is shown in FIG. 3, a transparent conductive film 100, which is formed by sequentially laminating the optical adjustment layer 2 and the transparent conductive layer 1 on the surface of at least one side of the base film 4 Transparent conductive film 100, characterized in that the optical adjustment layer 2 is a high refractive index layer 2b with a refractive index of 1.6 or more and a low refractive index layer with a refractive index of 1.45 or less from the base film 4 side 2a is laminated in sequence, and the low-refractive-index layer 2a contains silicon dioxide fine particles, and the proportion of voids where the aforementioned silicon dioxide fine particles are not present is set to 15% or more on the exposed surface side of the low-refractive-index layer 2a Value.

In the following, the second embodiment of the present invention omits parts that overlap with the contents so far, and only details the different parts.

1. Transparent conductive layer

(1) Material substance

In the transparent conductive film of the present invention, as the material of the transparent conductive layer, if it has both transparency and conductivity, it is not particularly limited, but examples include indium oxide, zinc oxide, tin oxide, and indium. Tin oxide (ITO), tin antimony oxide, zinc aluminum oxide, indium zinc oxide, etc.

Moreover, it is preferable to use ITO especially as a material substance.

This reason is because if it is ITO, a transparent conductive layer excellent in transparency and conductivity can be formed by adopting appropriate film forming conditions.

(2) Pattern shape

Further, it is preferable that the transparent conductive layer is formed by etching to form a pattern shape such as a linear shape or a lattice shape.

In addition, the pattern shape described above is preferably such that the line width of the portion where the transparent conductive layer exists and the line width of the portion where the transparent conductive layer does not exist are slightly equal.

Furthermore, the line width is usually 0.1 to 10 mm, preferably 0.2 to 5 mm, and particularly preferably 0.5 to 2 mm.

In addition, in the case where the above-mentioned line-shaped or grid-shaped line width is not limited to a certain case, for example, it is possible to freely select a shape related to the shape required by the capacitive touch panel.

Specifically, a pattern in which the diamond-shaped part and the line part are repeatedly connected can be cited Shapes, etc., such graphic shapes are also included in the "line" category.

(3) Film thickness

In addition, the thickness of the transparent conductive layer is preferably 5 to 500 nm.

This reason is because when the thickness of the transparent conductive layer is less than 5 nm, the transparent conductive layer may not only become brittle, but sufficient conductivity may not be obtained. In addition, when the thickness of the transparent conductive layer becomes a value exceeding 500 nm, the color taste of the transparent conductive layer is enhanced, and the pattern shape may be easily recognized.

Accordingly, the thickness of the transparent conductive layer is more preferably 15 to 250 nm, and even more preferably 20 to 100 nm.

2. Manufacturing method of transparent conductive film

For the optical adjustment layer obtained in step (b) of the method for manufacturing a transparent conductive layer-forming laminate described above, by vacuum evaporation method, sputtering method, CVD method, ion plating method, spray method, sol-gel A well-known method such as a method, and by forming a transparent conductive layer, a transparent conductive film can be obtained.

In addition, examples of the sputtering method include a general sputtering method using a compound, a reactive sputtering method using a metal target, and the like.

At this time, it is also preferable to introduce oxygen, nitrogen, water vapor, etc. as a reactive gas, or to use ozone addition or ion assist in combination.

Furthermore, after the transparent conductive layer is formed as described above, after forming a resist mask of a specific pattern by photolithography, an etching process can be performed by a well-known method to form a linear pattern.

In addition, as the etching solution, preferably, an aqueous solution of an acid such as hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid is used.

In addition, as the final step of the etching process, the solution used in the alkaline process for removing the remaining photoresist, from the viewpoint of rapid etching process, it is preferable to use a liquid temperature of 10 to 50°C and a concentration of 1 to 10 A strong alkaline aqueous solution with a weight% and a pH value of 13.4 to 14.4.

Further, suitable strong bases include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, calcium hydroxide, and hydroxide Strontium, barium hydroxide, europium (II) hydroxide, thallium (I) hydroxide, guanidine, etc.

In addition, in order to improve the crystallinity of the transparent conductive layer and reduce the resistivity, it is preferable to provide an annealing step to perform a specific annealing process.

That is, it is preferable to expose the obtained transparent conductive film to a temperature of 130 to 180°C for 0.5 to 2 hours.

[Example]

Hereinafter, the laminate for forming a transparent conductive layer of the present invention will be described in further detail with reference to examples.

[Example 1]

1. Preparation of the composition for forming the hard coat layer

In the container, contain amorphous silicon dioxide containing 60 parts by weight of ultraviolet-curable resin (manufactured by Showa Denko Co., Ltd., Vinylol FC-1000) (indicating the removal of the dilute solvent, the same below), and amorphous silicon dioxide Silicon 45 parts by weight of silica in the dispersion, 0.03 parts by weight with cross-linked acrylic copolymer resin (manufactured by Sekisui Chemical Industry Co., Ltd., Techpolymer XX-27LA), and a leveling agent for silica (BYK Chemie. Japan ( Co., Ltd., BKY-3550) 0.03 parts by weight, add a solvent and mix well to prepare a composition for forming a hard coat layer with a solid content concentration of 22% by weight.

2. Modulation of high refractive index layer forming composition

In a container, contain 100 parts by weight of ultraviolet curable resin (made by Dairi Seiki Chemical Co., Ltd., Seika Beam EXF-01L (NS)), and a dispersion liquid of zirconia (made by CIKNANOTEC Co., Ltd., ZRMIBK 15WT%-F85) After 200 parts by weight, 0.05 parts by weight with acrylic leveling agent (BYK Chemie. Japan, Co., Ltd., BYK-355), and 3 parts by weight with photopolymerization initiator (BASF Japan (Co., Ltd., Irgacure 907)), A solvent is added and mixed uniformly to prepare a composition for forming a high refractive index layer with a solid content concentration of 1% by weight.

3. Modulation of the composition for forming a low refractive index layer

In the container, the active energy ray-curable resin containing the water-repellent resin as the component (A), the silica fine particles as the (B) component, the leveling agent as the (C) component, and the (D) ) After the photopolymerization initiator of the component is contained in the following composition, a solvent is added and mixed uniformly to prepare a composition for forming a low refractive index layer with a solid content concentration of 1% by weight.

In addition, the blending amount in the following composition and the composition shown in Table 1 shows the pure content except the dilution solvent.

In addition, the volume average particle diameter (D50) of the component (B) described above is measured by a laser diffraction scattering type particle size distribution measuring device.

In the following, the photopolymerization initiator as the component (D) described above may be referred to as "Irgacure 184".

4. Formation of hard coating

As a base film, a polyester film with an adhesion layer of 125 μm in thickness (made by Teijin DuPont Co., Ltd., PET125KEL86W) was prepared.

Next, on the surface of the prepared base film, a composition for forming a hard coat layer is applied to Wire bar#8.

Next, after drying at 70°C for 1 minute, an ultraviolet irradiation device (manufactured by GS Yuasa Corporation) was used under a nitrogen atmosphere. Irradiate ultraviolet rays under the following conditions to form a hard coat layer with a thickness of 2 μm on the surface of the base film.

In addition, even on the surface on the opposite side of the base film, the same process is performed to form a hard coat layer.

Light source: high pressure mercury lamp

Illumination: 150mW/cm ²

Light quantity: 150mJ/cm ²

5. Formation of high refractive index layer

Next, on the hard coating layer on one side, a composition for forming a high refractive index is applied to Wire bar #4.

Next, after drying at 50°C for 1 minute, an ultraviolet irradiation device (manufactured by GS Yuasa Corporation) was used under a nitrogen atmosphere, and ultraviolet rays were irradiated under the same conditions as the hard coating to form a film thickness of 35 nm on the hard coating. High refractive index layer with refractive index n _D = 1.65.

6. Formation of low refractive index layer

Next, on the formed high-refractive index layer, a composition for forming a low-refractive index is coated on Wire bar#4.

Next, after drying at 50°C for 1 minute, an ultraviolet irradiation device (manufactured by GS Yuasa Corporation) was used under a nitrogen atmosphere, and ultraviolet rays were irradiated under the same conditions as the hard coat layer to form a film thickness of 50 nm on the high refractive index layer 1. A low-refractive-index layer with a refractive index n _D =1.37 to obtain a laminate for forming a transparent conductive layer as shown in FIG. 1(a).

7. Determination of porosity

On the exposed surface side of the low-refractive-index layer of the obtained laminate for forming a transparent conductive layer, the proportion of voids in which no silica fine particles were present, that is, the void ratio (%) was measured.

That is, using a field emission scanning electron microscope (FE-SEM) (manufactured by Hitachi High-Technologies Corporation, S-4700), under the conditions of an acceleration voltage of 10 kV and a measurement magnification of 5,000 times, the resulting transparent conductive layer was obtained The reflected electron image on the exposed surface side of the low-refractive-index layer of the laminate for formation (observation range: 450×575 μm ² ).

Secondly, the obtained reflected electron image was binarized using image processing software (Cybernetic Co., Ltd., Image Pro-plus), and the proportion of voids without silica particles, that is, the void ratio (%) was measured. , The porosity is 24.1%.

Still, the obtained reflected electron image is shown in FIG. 4(a).

8. Evaluation

(1) Evaluation of etching resistance 1

The etching resistance of the resulting laminate for forming a transparent conductive layer was evaluated by the increase rate (%) of the porosity (%) in the low refractive index layer (hereinafter sometimes referred to as "void increase rate").

That is, after immersing the laminate for forming a transparent conductive layer for 5 minutes and performing alkali treatment with a 5 wt% sodium hydroxide aqueous solution heated to 40°C, the porosity of the low refractive index layer was measured under the same conditions as above (%). The obtained reflected electron image is shown in Fig. 4(b).

Next, the porosity (%) after the alkali treatment is divided by the porosity (%) before the alkali treatment to calculate the void increase rate (%). Table 1 shows the obtained results.

Still, if the void increase rate is a value of 26% or less, it can be judged that it has excellent etching resistance in practical use.

(2) Evaluation of etching resistance 2

The amount of change (%) in the reflectance (%) of the obtained transparent conductive layer forming laminate by the etching resistance of the obtained transparent conductive layer forming laminate (hereinafter sometimes referred to as "reflectance change amount") Assessment.

That is, the reflectance (%) of the resulting laminate for forming a transparent conductive layer (on the side of the low refractive index layer) uses an ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometer (manufactured by Shimadzu Corporation, UV -3600), reflection angle: 8°, sampling interval: 1 nm, measurement mode: measurement under a single condition.

Next, after immersing the laminate for forming a transparent conductive layer for 5 minutes and performing alkali treatment with a 5 wt% sodium hydroxide aqueous solution heated to 40°C, the reflectance (%) was measured under the same conditions as above.

Next, the amount of reflectance change (%) is calculated by subtracting the reflectance (%) after alkali treatment from the reflectance (%) before alkali treatment. Table 1 shows the obtained results.

Still, if the amount of change in reflectance is 0.5% or less, it can be judged to have excellent etching resistance in practical use.

In addition, the reason why the etching resistance can be evaluated by the amount of change in reflectivity (%) is that, when the film thickness or refractive index of the low refractive index layer or both are changed by etching, the Reflectivity.

(3) Evaluation of etching resistance 3

The amount of change (nm) in the arithmetic mean surface roughness Ra (nm) on the exposed surface of the low refractive index layer on the etching resistance of the resulting transparent conductive layer forming laminate (hereinafter sometimes referred to as "Ra Change") evaluation.

That is, using a light interference type surface roughness meter (Veeco Co., Ltd., WYKO NT-1100), under the conditions of Measurement Type: PSI (Infinite Scan), Objective: 10.0X, FOV: 1.0X, the measured The arithmetic average roughness Ra (nm) of the exposed surface of the low refractive index layer of the laminate for forming a transparent conductive layer.

Next, data analysis was performed in Terms Removal: Tilt Only (Plane Fit) and Window Filtering: None, and the arithmetic average surface roughness Ra (nm) was measured.

Next, after immersing the laminate for forming a transparent conductive layer for 5 minutes and performing alkali treatment with a 5 wt% sodium hydroxide aqueous solution heated to 40°C, the arithmetic mean surface roughness Ra (nm) was measured under the same conditions as above .

Next, the arithmetic average surface roughness Ra (nm) after the alkali treatment is subtracted from the arithmetic average surface roughness Ra (nm) before the alkali treatment to calculate the amount of change in Ra (nm). Table 1 shows the obtained results.

Still, if the amount of change in the arithmetic mean surface roughness is less than 10 nm, it can be judged to have excellent etching resistance in practice.

(4) Evaluation of graphic visibility

A patterned transparent conductive layer was formed on the surface of the low refractive index layer of the obtained transparent conductive layer forming laminate, and its visibility was evaluated.

That is, after cutting the obtained laminate for forming a transparent conductive layer to 90 mm in length×90 mm in width, sputtering was performed using an ITO target (10% by weight of tin oxide and 90% by weight of indium oxide) on the center of the low refractive index layer A transparent conductive layer with a square shape of 60 mm in length and 60 mm in width and a thickness of 30 nm is formed in the portion.

Next, a photoresist film patterned in a lattice pattern is formed on the surface of the obtained transparent conductive layer.

Next, at room temperature, the transparent conductive layer was patterned into a lattice by immersing in 10% by weight hydrochloric acid for 1 minute and performing an etching process.

Next, immerse it for 5 minutes in a 5 wt% aqueous sodium hydroxide solution heated to 40°C to perform alkali treatment to remove the photoresist film on the transparent conductive layer to obtain a transparent conductive layer with a patterned transparent conductive layer Sexual film.

The transparent conductive film has a line portion made of ITO with a line width of 2 mm, and a square gap of 2 mm on one side has a 30 nm transparent conductive layer partitioned into a lattice pattern.

Next, the obtained transparent conductive film is placed at a position 1m from the white fluorescent lamp to reflect the state of the white fluorescent lamp on the transparent conductive film, by the transparent conductive on the same side as the white fluorescent lamp Film At a position of 30 cm, the pattern shape of the transparent conductive layer was visually observed and evaluated according to the following criteria. Table 1 shows the obtained results.

◎: The pattern shape of the transparent conductive layer cannot be distinguished

○: Only a few transparent conductive layers can be seen

×: Depending on the shape of the transparent conductive layer

(5) Evaluation of surface free energy

The evaluation of the measured surface free energy (mN/m) was conducted under the condition of 23° C. in accordance with JIS K 6768 of the obtained laminate for forming a transparent conductive layer.

That is, on the uppermost layer of the obtained transparent conductive layer forming laminate, that is, the lower refractive index layer, a wetting tension test solution of a specific surface tension was applied with a cotton swab to have a width of 10 mm and a length of 60 mm.

And if the coating film of the wetting tension test solution is directly interrupted for 2 seconds, the free energy on the surface is judged to be qualified, and the wetting tension test solution with a higher surface tension is used in sequence to continue the same operation, and the coating of the wetting tension test solution is repeated Until the film is interrupted within 2 seconds, the highest qualified surface free energy is used as the measurement result. Table 1 shows the obtained results.

Still, since wetting tension is synonymous with surface free energy thermodynamically, in the present invention, wetting tension is described as surface free energy.

[Example 2 and Comparative Examples 1-2]

In Example 2 and Comparative Examples 1-2, when preparing the composition for forming a low refractive index layer, except by using reactive hollow silica particles (volume (The average particle diameter (D50) 45nm) was changed as described in Table 1. The porosity of the low refractive index layer of the obtained transparent conductive layer forming laminate was changed as described in Table 1. In the same manner as in Example 1, a laminate for forming a transparent conductive layer was produced and evaluated. Table 1 shows the obtained results.

5(a) is the reflected electron image on the exposed surface of the low refractive index layer of the laminate for forming a transparent conductive layer before the alkali treatment of Comparative Example 1, and FIG. 5(b) is the alkali treatment of Comparative Example 1. Then, the reflected electron image of the exposed surface of the low refractive index layer of the laminate for forming a transparent conductive layer.

[Table 1]

[Industry availability]

As described above, according to the present invention, according to the present invention, the low refractive index layer of the outermost surface layer of the laminate for forming a transparent conductive layer is formed to contain silicon dioxide, and at the same time on the exposed surface side of the low refractive index layer, by By setting the ratio of voids in which silicon dioxide fine particles are not present to a value of 15% or more, a laminate for forming a transparent conductive layer having excellent etching resistance in a low refractive index layer can be obtained.

As a result, the pattern shape of the transparent conductive layer can be stably invisible even after strict etching treatment, and a laminate for forming a transparent conductive layer having excellent adhesion to the transparent conductive layer and the like can be obtained.

Accordingly, the laminate for forming a transparent conductive layer of the present invention and the transparent conductive film using the same are expected to contribute significantly to the improvement of the quality of the touch panel.

2‧‧‧Optical adjustment layer

2a‧‧‧Low refractive index layer

2b‧‧‧High refractive index layer

3‧‧‧hard coating

4‧‧‧ Base film

10‧‧‧Laminate for transparent conductive layer formation

Claims (8)

A laminate for forming a transparent conductive layer, which is a laminate for forming a transparent conductive layer having an optical adjustment layer on at least one surface of a base film, and a hard coat layer is provided on both sides or one side of the base film, It is characterized in that the optical adjustment layer is formed by sequentially laminating a high-refractive-index layer having a refractive index of 1.6 or more and a low-refractive-index layer having a refractive index of 1.45 or less from the base film side. The low-refractive-index layer contains silicon dioxide fine particles, and on the exposed surface side of the low-refractive-index layer, the ratio of voids where the silicon dioxide fine-particles are not present is set to a value of 15% or more, and the low refractive index The surface free energy of the layer is set to a value above 37 mN/m. The laminate for forming a transparent conductive layer according to claim 1, which sets the volume average particle diameter (D50) of the silicon dioxide fine particles to a value in the range of 20 to 70 nm. The laminate for forming a transparent conductive layer according to claim 1, wherein the silicon dioxide fine particles are hollow silicon dioxide fine particles. The laminate for forming a transparent conductive layer according to any one of claims 1 to 3, wherein the silicon dioxide fine particles are reactive silicon dioxide fine particles. The laminate for forming a transparent conductive layer according to claim 1, wherein the matrix portion of the low refractive index layer contains a cured product of an active energy ray-curable resin. The laminate for forming a transparent conductive layer according to claim 1, which sets the film thickness of the aforementioned low refractive index layer to a value in the range of 20 to 80 nm. A transparent conductive film, which is a transparent conductive film formed by sequentially laminating an optical adjustment layer and a transparent conductive layer on the surface of at least one side of a base film, and is provided on both sides or one side of the base film The hard coat layer is characterized in that the optical adjustment layer is sequentially laminated from the substrate film side according to a high refractive index layer having a refractive index of 1.6 or more, and a low refractive index layer having a refractive index of 1.45 or less. At the same time, the low-refractive-index layer contains silicon dioxide fine particles, and on the exposed surface side of the low-refractive-index layer, the proportion of voids in which the silicon dioxide fine particles are not present is set to a value of 15% or more. The free energy on the surface of the low refractive index layer is set to a value of 37 mN/m or more. The transparent conductive film according to claim 7, wherein the transparent conductive layer is patterned by etching.

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