JP6628974B2 - Transparent conductive film - Google Patents

Description

The present invention relates to a transparent conductive layer-forming laminate and a transparent conductive film.
In particular, for forming a transparent conductive layer having excellent etching resistance in a low refractive index layer, capable of stably making the pattern shape of a transparent conductive layer invisible, and having excellent adhesion to a transparent conductive layer and the like. The present invention relates to a laminate and a transparent conductive film using the same.

2. Description of the Related Art Conventionally, a touch panel capable of inputting information by directly touching an image display unit has a light-transmitting input device arranged on a display.
As a typical form of such a touch panel, a low resistance film type touch panel in which two transparent electrode substrates are arranged while providing a gap so that respective transparent electrode layers face each other, or between a transparent electrode film and a finger There is a capacitive touch panel that utilizes a change in the generated capacitance.

Among these, in a capacitive touch panel, a sensor for detecting a touch position of a finger is roughly classified into a glass sensor in which a transparent conductive layer is laminated on a glass substrate, and a transparent conductive layer in a transparent plastic film substrate. And a film sensor laminated thereon.
In particular, in a film sensor, a grid-like pattern is formed by arranging two transparent conductive films having a transparent conductive layer patterned in a line shape so that each pattern crosses each other. There are many.

However, when the transparent conductive layer is patterned as described above, the boundary between the pattern portion and the non-pattern portion is easily visually recognized, and the problem that the appearance of the capacitive touch panel deteriorates has been observed.
Therefore, techniques for solving such a problem have been disclosed (for example, see Patent Documents 1 and 2).

  That is, Patent Document 1 discloses a laminated film in which a resin layer is provided on at least one side of a polyester film, wherein the resin layer contains at least silica particles (B) and an acrylic resin (D), Are hollow particles and / or particles having pores, and the silica particles have a number average particle diameter of 30 nm or more and 120 nm or less, and the acrylic resin (D) is represented by the following general formula (1) ( It is a resin using a (meth) acrylate monomer (d-1) and a (meth) acrylate monomer (d-2) represented by the following general formula (2), and has a minimum reflectance on the resin layer side of the laminated film. An optical laminated film characterized by being 2.0% or less is disclosed.

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

(In the 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 carbon rings.)

Further, Patent Document 2 has a transparent conductor layer on at least one side of a transparent film substrate via at least one undercoat layer, and the transparent conductor layer is patterned, and A method for producing a transparent conductive film having at least one undercoat layer in a non-patterned portion having no transparent conductive layer, comprising forming a transparent film substrate on one or both sides of a transparent film substrate. Forming a formed undercoat layer with an organic material, forming a transparent conductor layer on the undercoat layer by a sputtering method, and etching and patterning the transparent conductor layer. A method for producing a transparent conductive film is disclosed.
It also describes that the above-mentioned undercoat layer is composed of two layers, and the outermost undercoat layer is a SiO ₂ film formed by applying silica sol.

Japanese Patent Application Laid-Open No. 2013-52676 (Claims) Japanese Patent Application Laid-Open No. 2011-14089 (Claims)

However, when the transparent conductive layer is patterned by etching, the resin layer on which the transparent conductive layer is formed is easily eroded by the etchant when the transparent conductive layer is patterned by etching. There was a problem that it was difficult to stably invisible the pattern shape.
More specifically, in recent years, with the increase in production of smartphones and the like, rapid etching processing is required, and in particular, alkali processing for removing the remaining photoresist, which is the final step of the etching processing, For example, a 5% by weight aqueous sodium hydroxide solution heated to 40 ° C. may be used.
When such severe alkali treatment is performed, in the optical laminated film disclosed in Patent Document 1, the silica particles in the resin layer are easily melted or dropped, and as a result, the transparent conductive layer is stably formed. There is a problem that it is difficult to make the pattern shape invisible.

Also, in the case of a transparent conductive film obtained by the production method disclosed in Patent Document 2, when severe alkali treatment is performed, silica particles in the SiO ₂ film are easily melted or dropped off. In addition, there has been a problem that it is difficult to stably make the pattern shape of the transparent conductive layer invisible.

Then, the present inventors, in view of the above circumstances, and made intensive efforts, while containing silica in the low refractive index layer, which is the outermost layer of the transparent conductive layer forming laminate, the low refractive index layer The inventors have found that the above-mentioned problem can be solved by setting the ratio of voids on which the silica fine particles are not present on the exposed surface side to a value of 15% or more, thereby completing the present invention.
That is, an object of the present invention is to provide a low-refractive-index layer with excellent etching resistance, which can stably make the pattern shape of the transparent conductive layer invisible even under severe etching conditions, and It is an object of the present invention to provide a transparent conductive layer-forming laminate excellent in adhesion between layers and the like, and a transparent conductive film using the same.

According to the present invention, a transparent conductive layer-forming laminate having an optical adjustment layer on at least one surface of a substrate, wherein the optical adjustment layer has a refractive index of 1.6 or more from the base film side. And a low-refractive-index layer having a refractive index of 1.45 or less, and the low-refractive-index layer contains fine silica particles, and the low-refractive-index layer is The transparent conductive layer-forming laminate characterized in that the ratio of voids on which the silica fine particles are not present on the exposed surface side is set to a value of 15% or more, and the above-mentioned problem can be solved.
More specifically, it is a laminate for forming a transparent conductive layer having an optical adjustment layer on at least one surface of a substrate film, wherein a hard coat layer is provided on both surfaces or one surface of the substrate film, The layer is formed by sequentially stacking, from the base film side, 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. The low refractive index layer contains silica fine particles, and the ratio of voids on the exposed surface side of the low refractive index layer where no silica fine particles exist is set to a value of 15% or more, and the surface free energy in the low refractive index layer is 37 mN. / M or more.
That is, if the transparent conductive layer forming laminate of the present invention, while containing the silica fine particles in the low refractive index layer that is the outermost layer of the transparent conductive layer forming laminate, on the exposed surface side of the low refractive index layer. Since the ratio of voids in which silica fine particles do not exist (hereinafter sometimes referred to as “porosity”) is set to a value of 15% or more, even when etching treatment including severe alkali treatment is performed, The rate of change of the porosity of the low refractive index layer before and after that (hereinafter, may be referred to as the “rate of change of porosity”) can be effectively reduced.
More specifically, it is possible to effectively prevent the silica fine particles in the low refractive index layer from melting or falling off by the etching treatment (hereinafter, such an effect may be referred to as “etching resistance”). ).
As a result, even when an etching process including a severe alkali process is performed, the predetermined refractive index required for the low refractive index layer can be effectively maintained, and as a result, the pattern shape of the transparent conductive layer can be maintained. Can be stably made invisible.
Further, even when etching treatment including severe alkali treatment is performed, since the rate of change of voids in the low refractive index layer before and after the etching treatment can be effectively reduced, the low refractive index caused by silica fine particles can be reduced. Fine irregularities on the surface of the layer can also be effectively maintained.
In addition, by setting the surface free energy of the low refractive index layer to a value of 37 mN / m or more, it is possible to improve the etching resistance and to achieve a predetermined adhesion to the transparent conductive layer or the like required for the low refractive index layer. It can be obtained more effectively.
Accordingly, the surface free energy on the surface of the low-refractive-index layer can be maintained in a predetermined range, and a predetermined adhesiveness to the transparent conductive layer or the like required for the low-refractive-index layer can be obtained.

Further, in constituting the laminate for forming a transparent conductive layer of the present invention, the volume average particle diameter (D50) of the silica fine particles is preferably set to a value within the range of 20 to 70 nm.
With this configuration, a predetermined refractive index can be obtained without lowering the transparency of the low refractive index layer.

In constituting the laminate for forming a transparent conductive layer of the present invention, the silica fine particles are preferably hollow silica fine particles.
With this configuration, the refractive index of the silica fine particles is further reduced, so that the refractive index of the low refractive index layer can be more effectively adjusted to a predetermined refractive index even with a small amount.

Further, in constituting the laminate for forming a transparent conductive layer of the present invention, the silica fine particles are preferably reactive silica fine particles.
With this configuration, since the silica fine particles can be firmly fixed to the low refractive index layer, the etching resistance can be more effectively improved.

Further, in constituting the laminate for forming a transparent conductive layer of the present invention, the matrix portion in the low refractive index layer preferably contains a cured product of an active energy ray-curable resin.
With this configuration, the silica fine particles in the low refractive index layer can be more effectively protected, so that the etching resistance can be more effectively improved.

In constituting the transparent conductive layer forming laminate of the present invention, the active energy ray-curable resin preferably contains a water-repellent resin.
With this configuration, the silica fine particles in the low refractive index layer can be more effectively protected, so that the etching resistance can be more effectively improved.

Further, in constituting the laminate for forming a transparent conductive layer of the present invention, the surface free energy of the low refractive index layer is preferably set to a value of 37 mN / m or more.
With this configuration, it is possible to more effectively obtain a predetermined adhesion to a transparent conductive layer or the like required for the low refractive index layer while improving the etching resistance.

In forming the transparent conductive layer-forming laminate of the present invention, the thickness of the low refractive index layer is preferably set to a value within the range of 20 to 80 nm.
With this configuration, sufficient etching resistance can be obtained, and thus, even under severe etching conditions, the pattern shape of the transparent conductive layer can be more stably invisible, and further, The porosity and the surface roughness can be easily controlled by adjusting the amount of the silica fine particles.

Another aspect of the present invention is a transparent conductive film obtained by sequentially laminating an optical adjustment layer and a transparent conductive layer on at least one surface of a base film, wherein the optical adjustment layer has From the film side, 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 are sequentially laminated, and a low refractive index layer is formed. Is a transparent conductive film containing silica fine particles and having a ratio of voids on the exposed surface side of the low refractive index layer where no silica fine particles are present to a value of 15% or more.
That is, a transparent conductive film obtained by sequentially laminating an optical adjustment layer and a transparent conductive layer on at least one surface of the base film, and a hard coat layer is provided on both sides or one side of the base film. The optical adjustment layer is formed by sequentially laminating, from the base film side, 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 addition, the low refractive index layer contains silica fine particles, and the ratio of voids where no silica fine particles are present on the exposed surface side of the low refractive index layer is set to a value of 15% or more. A transparent conductive film, wherein the energy is a value of 37 mN / m or more.
Therefore, in the case of the transparent conductive film of the present invention, since the predetermined transparent conductive layer forming laminate is used, the etching resistance of the low refractive index layer is excellent, and the pattern shape of the transparent conductive layer is stably invisible. And excellent adhesion to a transparent conductive layer or the like can be obtained.
In addition, by setting the surface free energy of the low refractive index layer to a value of 37 mN / m or more, it is possible to improve the etching resistance and to improve the predetermined adhesion to the transparent conductive layer and the like required for the low refractive index layer. It can be obtained more effectively.

In constituting the transparent conductive film of the present invention, the transparent conductive layer is preferably patterned by etching.
Even in the case of such a configuration, the pattern shape of the transparent conductive layer can be made invisible stably due to the excellent etching resistance of the low refractive index layer.

FIGS. 1A and 1B are diagrams provided for explaining the configuration of the transparent conductive layer forming laminate of the present invention. FIG. 2 is a diagram provided to explain the porosity in the low refractive index layer. FIG. 3 is a diagram provided for explaining the configuration of the transparent conductive film of the present invention. 4A and 4B are backscattered electron images on the exposed surface of the low refractive index layer in Example 1. FIG. 5A and 5B are backscattered electron images on the exposed surface of the low refractive index layer in Comparative Example 1.

[First Embodiment]
The first embodiment of the present invention is a transparent conductive layer forming laminate 10 having an optical adjustment layer 2 on at least one surface of a base film 4 as shown in FIG. The layer 2 includes, from the side of the base film 4, a high refractive index layer 2 b having a refractive index of 1.6 or more and a low refractive index layer 2 a having a refractive index of 1.45 or less. As shown in FIG. 2, the low refractive index layer 2a contains silica fine particles, and as shown in FIG. 2, the ratio of the voids 22 where the silica fine particles 20 do not exist on the exposed surface side of the low refractive index layer 2a (exposed). The transparent conductive layer forming laminate 10 is characterized in that the ratio of the voids to the area of the surface) is 15% or more.
In FIG. 1A, the transparent conductive layer forming laminate 10 having the hard coat layers 3 on both sides of the base film 4 is shown as an example, but the hard coat layer 3 may be omitted. it can.
In FIG. 1A, the particles in each layer represent silica fine particles and metal oxide particles.
Hereinafter, a first embodiment of the present invention will be specifically described with reference to the drawings as appropriate.

1. Substrate Film (1) Type The type of the substrate film is not particularly limited, and a known substrate film can be used as an optical substrate.
For example, polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), polyethylene films, polypropylene films, cellophane, diacetyl cellulose films, triacetyl cellulose films, acetyl cellulose butyrate films, polyvinyl chloride films , Polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide Film, fluororesin film, polyamide film, Lil resin film, norbornene resin film, can be exemplified preferably a plastic film such as a cycloolefin resin film.

Among these, from the viewpoint of heat resistance, polyester films, polycarbonate films, polyimide films, norbornene-based resin films, and cycloolefin resin films are more preferable.
Further, from the viewpoint of transparency and compatibility between film strength and flexibility, a PET film is particularly preferable.

(2) Thickness The thickness of the substrate film is preferably set to a value within the range of 20 to 200 μm.
The reason for this is that when the thickness of the base film is less than 20 μm, the strength of the base film is reduced, so that the annealing process is performed during the presence and absence of the transparent conductive layer in the optical adjustment layer. This is because the occurrence of distortion may not be effectively suppressed. On the other hand, if the thickness of the base film exceeds 200 μm, optical properties such as transparency of the base film may be deteriorated.
Therefore, the thickness of the base film is more preferably set to a value in the range of 30 to 180 μm, and further preferably to a value in the range of 50 to 150 μm.
In addition, "annealing treatment" means that the transparent conductive layer laminated on the transparent conductive layer forming laminate is crystallized by heat treatment in order to improve the electrical conductivity of the transparent conductive layer in the transparent conductive film. Process.

2. Hard Coat Layer As shown in FIG. 1A, in forming the transparent conductive layer forming laminate 10 of the present invention, it is preferable to provide the hard coat layer 3 on both sides or one side of the base film 4.
The reason for this is that by providing such a heart coat layer, in the manufacturing process of the transparent conductive layer forming laminate, it is possible to impart scratch resistance to the base film and prevent the optical properties from being lowered, This is because it is possible to suppress the occurrence of a phenomenon that the base films adhere to each other when the base film is wound up in a roll shape (hereinafter, such an effect may be referred to as “anti-blocking property”). .

(1) Material The hard coat layer is preferably made of a cured product of a composition containing silica fine particles and an active energy ray-curable resin as the material.
The reason for this is that, by containing the silica fine particles and the active energy ray-curable resin, the anti-blocking property can be imparted, so that not only the improvement of the winding property can be expected but also the high refractive index layer which is the upper layer of the hard coat layer. This is because the adhesiveness can be improved and the layers can be firmly laminated.

(1) -1 Active energy ray-curable resin The active energy ray-curable resin used for forming the hard coat layer is a resin having an energy quantum in an electromagnetic wave or a charged particle beam, that is, an ultraviolet ray or an electron beam. Irradiation means a polymerizable compound which crosslinks and cures, and includes, for example, a photopolymerizable prepolymer and a photopolymerizable monomer.

  The photopolymerizable prepolymers described above include a radical polymerization type and a cationic polymerization type. Examples of the radical polymerization type photopolymerizable prepolymer include polyester acrylates, epoxy acrylates, urethane acrylates, and polyol acrylates. Is mentioned.

Further, as the polyester acrylate prepolymer, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, or And a compound obtained by esterifying a hydroxyl group at a terminal of an oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth) acrylic acid.
Examples of the epoxy acrylate prepolymer include compounds obtained by esterifying the oxirane ring of a bisphenol epoxy resin or a novolak epoxy resin having a relatively low molecular weight with (meth) acrylic acid.
Examples of the urethane acrylate prepolymer include compounds obtained by esterifying a polyurethane oligomer obtained by a reaction between a polyether polyol or a polyester polyol and a polyisocyanate with (meth) acrylic acid.
Further, examples of the polyol acrylate-based prepolymer include compounds obtained by esterifying hydroxyl groups of polyether polyol with (meth) acrylic acid.
These polymerizable prepolymers may be used alone or in combination of two or more.

On the other hand, as the cationically polymerizable photopolymerizable prepolymer, an epoxy resin is usually used.
As such an epoxy resin, for example, a compound obtained by epoxidizing a polyhydric phenol such as a bisphenol resin or a novolak resin with epichlorohydrin or the like, or obtained by oxidizing a linear olefin compound or a cyclic olefin compound with a peroxide or the like. And the like.

Examples of the photopolymerizable monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol di (meth). Acrylate, neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphoric acid Di (meth) acrylate, allylated cyclohexyldi (meth) acrylate, isocyanurate di (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythri Tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified Examples include polyfunctional acrylates such as dipentaerythritol hexa (meth) acrylate.
These photopolymerizable monomers may be used alone or in combination of two or more.

(1) -2 Photopolymerization initiator Further, since the active energy ray-curable resin can be efficiently cured by active energy rays, particularly ultraviolet rays, it is also preferable to use a photopolymerization initiator in combination, if desired.
Examples of such a photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, and benzoin with respect to radical polymerizable photopolymerizable prepolymers and photopolymerizable monomers. Isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- Hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) keto Benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone , 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, and the like.

Further, as the photopolymerization initiator for the photopolymerizable prepolymer of the cationic polymerization type, for example, onium such as aromatic sulfonium ion, aromatic oxosulfonium ion, aromatic iodonium ion, tetrafluoroborate, hexafluorophosphate, hexa Compounds composed of anions such as fluoroantimonate and hexafluoroarsenate are exemplified.
In addition, these may be used individually by 1 type, and may be used in combination of 2 or more types.
Further, the compounding amount of the photopolymerization initiator is preferably set to a value within the range of 0.2 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the above-mentioned active energy ray-curable resin. It is more preferable to set the value within the range.

(1) -3 Silica Fine Particles As the silica fine particles, silica fine particles having a polymerizable unsaturated group-containing organic compound bonded thereto, or ordinary colloidal silica fine particles not having such a polymerizable unsaturated group-containing organic compound are used. Can be used.
Further, as the silica fine particles to which the polymerizable unsaturated group-containing organic compound is bonded, a functional group capable of reacting with the silanol group on the surface of the silica fine particle having a volume average particle diameter (D50) of about 0.005 to 1 μm is used. Examples thereof include those obtained by reacting a polymerizable unsaturated group-containing organic compound having a group.
The above-mentioned polymerizable unsaturated groups include, for example, radically polymerizable acryloyl groups and methacryloyl groups.
Further, as the ordinary colloidal silica fine particles having no polymerizable unsaturated group-containing organic compound, silica fine particles having a volume average particle diameter of about 0.005 to 1 μm, preferably about 0.01 to 0.2 μm, include alcohols. Colloidal silica suspended in a colloidal state in an organic or cellosolve-based organic solvent can be suitably used.
The average particle size of the silica fine particles can be determined, for example, by a zeta potential measurement method, can also be determined by using a laser diffraction scattering type particle size distribution measuring device, and can also be determined based on an SEM image. .
The amount of the silica fine particles is preferably 5 to 400 parts by weight, more preferably 20 to 150 parts by weight, and more preferably 30 to 100 parts by weight, based on 100 parts by weight of the active energy ray-curable resin. Is more preferable.

(2) Composition for forming a hard coat layer The hard coat layer is preferably formed by preparing a composition for forming a hard coat layer in advance, applying and drying and curing as described below.
The composition, if necessary, in an appropriate solvent, an active energy ray-curable resin, a photopolymerization initiator, silica fine particles, and various additives used as desired are added at predetermined ratios, respectively, and dissolved or dispersed. Can be prepared.
In addition, examples of the various additive components include an antioxidant, an ultraviolet absorber, a (near) infrared absorber, a silane coupling agent, a light stabilizer, a leveling agent, an antistatic agent, and an antifoaming agent.

Examples of the solvent used include, for example, aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol and butanol. Examples thereof include ketones such as alcohol, acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve.
The concentration and viscosity of the composition for forming a hard coat layer thus prepared are not particularly limited as long as they can be coated, and can be appropriately selected according to the situation.
Therefore, usually, from the viewpoint of easily adjusting the thickness of the obtained composition for forming a hard coat layer to a predetermined range, it is preferable to dilute the solid composition to have a solid concentration of 0.05 to 10% by weight, and 0.1. It is more preferable to dilute so as to be 8% by weight.

(3) Film Thickness The thickness of the hard coat layer is preferably set to a value within a range of 1 to 15 μm.
The reason for this is that when the thickness of the hard coat layer is less than 1 μm, the function of holding the substrate film against thermal shrinkage due to the annealing treatment becomes insufficient, and the occurrence of curling may not be suppressed. On the other hand, if the thickness of the hard coat layer exceeds 15 μm, outgassing may easily occur from the hard coat layer due to the annealing treatment.
Therefore, the thickness of the hard coat layer is more preferably set to a value in the range of 1.5 to 10 μm, and further 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 high refractive index layer has a refractive index of 1.6 or more.
The reason is that when the refractive index of the high refractive index layer is less than 1.6, a significant difference in refractive index from the low refractive index layer cannot be obtained, and the pattern shape of the transparent conductive layer may be easily recognized. Because there is. On the other hand, if the refractive index of the high refractive index layer is excessively large, the film of the high refractive index layer may become brittle.
Therefore, the refractive index of the high refractive index layer is more preferably set to a value within the range of 1.61 to 2, and further preferably set to a value within the range of 1.63 to 1.8.

(1) -2 Material Substance It is preferable that the high refractive index layer is made of a cured product of a composition containing metal oxide fine particles as a material substance and an active energy ray-curable resin.
This is because the adjustment of the refractive index in the high refractive index layer becomes easy by including the metal oxide fine particles and the active energy ray-curable resin.

Further, as the kind of the metal oxide, 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 are preferably mentioned. .
From the viewpoint of realizing a high refractive index without lowering the transparency, at least one selected from titanium oxide and zirconium oxide is particularly preferable.
These metal oxides may be used alone or in combination of two or more.
Further, the volume average particle diameter (D50) of the metal oxide fine particles is preferably set to a value in the range of 0.005 μm to 1 μm.
The volume average particle diameter (D50) of the metal oxide fine particles can be determined by, for example, a measurement method using a zeta potential measurement method, or can be determined by using a laser diffraction scattering type particle size distribution analyzer. Furthermore, it can be determined based on the SEM image.
As the active energy ray-curable resin and the photopolymerization initiator used for the high refractive index layer, those described in the description of the hard coat layer can be appropriately used.
Further, the compounding amount of the metal oxide fine particles is preferably 20 to 2,000 parts by weight, more preferably 80 to 1000 parts by weight, and more preferably 150 to 1000 parts by weight based on 100 parts by weight of the active energy ray-curable resin. More preferably, it is 400 parts by weight.

(1) -3 Composition for forming high-refractive-index layer The high-refractive-index layer is formed by preparing a composition for forming a high-refractive-index layer in advance, applying and drying and curing as described later. Is preferred.
The composition, if necessary, in an appropriate solvent, an active energy ray-curable resin, a photopolymerization initiator, metal oxide fine particles, and various additive components used as desired are added at predetermined ratios, respectively, and dissolved or dissolved. It can be prepared by dispersing.
In addition, the concentration, viscosity, and the like of the various additive components, the solvent, and the composition for forming the high refractive index layer are the same as those in the description of the hard coat layer.

(1) -4 Thickness The thickness of the high refractive index layer is preferably set to 20 to 130 nm.
The reason for this is that if the 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. On the other hand, if the thickness of the high refractive index layer exceeds 130 nm, the pattern shape of the transparent conductive layer may be easily recognized.
Therefore, the thickness of the high refractive index layer is more preferably 23 to 120 nm, and further preferably 30 to 110 nm.

(2) Low refractive index layer (2) -1 Refractive index The refractive index of the low refractive index layer is set to 1.45 or less.
The reason is that when the refractive index of the low refractive index layer exceeds 1.45, a significant refractive index difference from the high refractive index layer cannot be obtained, and the pattern shape of the transparent conductive layer is easily recognized. Because there is. On the other hand, if the refractive index of the low refractive index layer is excessively small, the film of the low refractive index layer may become brittle.
Therefore, the refractive index of the low refractive index layer is more preferably set to a value within a range of 1.3 to 1.44, and further preferably set to a value within a range of 1.35 to 1.43.

(2) -2 Material Substance The low refractive index layer in the present invention is preferably formed by photocuring a composition for forming a low refractive index layer containing the following components (A) and (B) as a material substance.
(A) 100 parts by weight of active energy ray-curable resin (B) 2 to 120 parts by weight of silica fine particles The reason for this is that the composition for forming a low refractive index layer used for forming a low refractive index layer is hardened by active energy ray curing. By containing the silica fine particles in a relatively small range with respect to the conductive resin, it becomes easy to adjust the porosity in the low refractive index layer to a value of 15% or more, and the etching resistance in the low refractive index layer is effectively improved. It is because it can be improved.
Further, the active energy ray-curable resin forms a matrix portion in the low refractive index layer by curing, more effectively protects silica fine particles in the low refractive index layer, and further effectively improves etching resistance. it can.
Hereinafter, each component will be described.

(I) Component (A): Active energy ray-curable resin The component (A) is an active energy ray-curable resin.
As the active energy ray-curable resin as the component (A), the photopolymerizable prepolymer and the photopolymerizable monomer described in the description of the hard coat layer can be appropriately used.

Further, the active energy ray-curable resin preferably contains a water-repellent resin.
The reason for this is that by containing the water-repellent resin, the silica fine particles in the low refractive index layer can be more effectively protected, so that the etching resistance can be more effectively improved.
Further, in the case of a water-repellent resin, the refractive index of the low refractive index layer is more easily determined because the refractive index is lower than that of the (meth) acrylic ultraviolet curable resin which is the main active energy ray-curable resin. It is because it can be reduced to the range of.
The water-repellent resin is not particularly limited as long as it is a resin having water repellency, and a conventionally known water-repellent resin can be used.
More specifically, as long as the surface free energy of the resin film formed of the water-repellent resin alone is in the range of 10 to 30 mN / m, it can be suitably used as the water-repellent resin in the present invention.

Further, specific examples of the water-repellent resin include, for example, a silicone resin and a fluorine resin such as polyvinylidene fluoride, a fluorine-based acrylic resin, and polyfluoroethylene.
Further, among them, it is preferable to use a fluorine resin, and particularly preferable is a reactive fluorine acrylic resin.
The reason for this is that the fluorine resin can more effectively protect the silica fine particles in the low refractive index layer, so that the etching resistance can be more effectively improved.

Further, the content of the water-repellent resin is preferably set to a value within the range of 50 to 90% by weight, when the entire component (A) is 100% by weight.
The reason is that when the content of the water-repellent resin is less than 50% by weight, it becomes difficult to effectively protect the silica fine particles in the low refractive index layer, and it is difficult to improve the etching resistance. This is because it may be. In addition, it is sometimes difficult to set the refractive index of the low refractive index layer to a sufficiently low value. On the other hand, if 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 a predetermined value for the transparent conductive layer or the like required for the refractive-index layer. This is because it may be difficult to obtain the close contact.
Therefore, when the content of the water-repellent resin is 100% by weight of the entire component (A), the content is more preferably in the range of 60 to 85% by weight, and more preferably in the range of 70 to 80% by weight. More preferably, it is set to a value.

(Ii) Component (B): silica fine particles The component (B) is silica fine particles.
The type of the silica fine particles is not particularly limited, but it is preferable to use hollow silica fine particles.
The reason is that the hollow silica fine particles contain air in the hollow portion inside, so that the refractive index of the silica fine particles as a whole is further reduced, and even if the amount is small, the refractive index is reduced more efficiently. This is because the refractive index of the refractive index layer can be adjusted to a predetermined refractive index.
In addition, "hollow silica fine particles" means silica fine particles having cavities inside the particles.

Further, the silica fine particles are preferably reactive silica fine particles.
This is because the reactive silica fine particles can firmly fix the silica fine particles to the low refractive index layer, so that the etching resistance can be more effectively improved.
The “reactive silica fine particles” are silica fine particles to which a polymerizable unsaturated group-containing organic compound is bonded, and have a functional group capable of reacting the silanol group with a silanol group on the surface of the silica fine particle. It can be obtained by reacting a saturated group-containing organic compound.
Examples of the above-mentioned polymerizable unsaturated group include a radically polymerizable acryloyl group and a methacryloyl group.

Further, the volume average particle diameter (D50) of the silica fine particles is preferably set to a value in the range of 20 to 70 nm.
The reason for this is that by setting the volume average particle diameter (D50) of the silica fine particles to a value within this range, a predetermined refractive index can be obtained without lowering the transparency of the low refractive index layer. .
That is, when the volume average particle diameter (D50) of the silica fine particles is less than 20 nm, in particular, in the case of hollow silica fine particles, it is difficult to sufficiently secure a cavity inside the particles due to its structure, and the low refractive index is low. This is because the effect of lowering the refractive index of the layer may be insufficient. On the other hand, when the volume average particle diameter (D50) of the silica fine particles exceeds 70 nm, light scattering is likely to occur, and the transparency of the low refractive index layer may be easily reduced.
Therefore, the volume average particle diameter (D50) of the silica fine particles is more preferably set to a value within the range of 30 to 60 nm, and even more preferably set to a value within the range of 40 to 50 nm.
The volume average particle diameter (D50) of the silica fine particles can be determined, for example, by a zeta potential measurement method or by using a laser diffraction / scattering particle size distribution analyzer, and further, based on an SEM image. You can also ask.

Further, it is preferable that the blending amount of the silica fine particles is a value within the range of 2 to 120 parts by weight based on 100 parts by weight of the active energy ray-curable resin containing the water-repellent resin as the component (A).
The reason for this is that when the amount of the silica fine particles is less than 2 parts by weight, it becomes difficult to sufficiently lower the refractive index of the low refractive index layer, or sufficient surface irregularities are formed on the surface of the low refractive index layer. This is because it may be difficult to form, and it may be difficult to obtain a predetermined adhesion to a transparent conductive layer or the like. On the other hand, when the amount of the silica fine particles exceeds 120 parts by weight, it becomes difficult to adjust the porosity in the low refractive index layer to a value of 15% or more, and etching treatment including severe alkali treatment is performed. This is because, in such a case, the silica fine particles in the low refractive index layer may be easily dissolved or dropped.
Therefore, it is more preferable to set the blending amount of the silica fine particles to a value within the range of 30 to 110 parts by weight based on 100 parts by weight of the active energy ray-curable resin containing the water-repellent resin as the component (A). , 50 to 100 parts by weight.

(2) -3 Low-refractive-index layer-forming composition The low-refractive-index layer is formed by preparing a low-refractive-index layer-forming composition in advance, coating, drying, and curing as described below.
The composition is, if necessary, in an appropriate solvent, an active energy ray-curable resin as the component (A), silica fine particles as the component (B), and a photopolymerization initiator and other various additional components. Can be prepared by adding or dissolving at predetermined ratios, respectively.
The various additives, the solvent, the concentration and the viscosity of the composition for forming the low refractive index layer, and the like are the same as those in the description of the hard coat layer.

(2) -4 Thickness The thickness of the low refractive index layer is preferably set to a value within the range of 20 to 80 nm.
The reason is that by setting the thickness of the low refractive index layer to a value within the above range, sufficient etching resistance can be obtained, and thereby, the pattern shape of the transparent conductive layer can be more stably invisible. This is because the porosity and the surface roughness can be easily controlled by adjusting the blending amount of the silica fine particles.
That is, when the thickness of the low-refractive-index layer is less than 20 nm, the low-refractive-index layer may become brittle, resulting in insufficient etching resistance. On the other hand, when the thickness of the low refractive index layer exceeds 80 nm, the pattern shape of the transparent conductive layer is easily recognized, and at the same time, the void ratio may not be calculated due to the definition of the void described later. is there.
Therefore, the thickness of the low refractive index layer is more preferably set to a value in the range of 25 to 70 nm, and even more preferably to a value in the range of 40 to 60 nm.

(2) -5 Porosity In the present invention, as shown in FIG. 2, the ratio of the voids 22 where the silica fine particles 20 are not present on the exposed surface side of the low refractive index layer 2a (the ratio of the voids to the area of the exposed surface). Is 15% or more.
The reason is that by setting the porosity to a value of 15% or more, even when etching treatment including severe alkali treatment is performed, the porosity change rate in the low refractive index layer before and after the etching treatment can be effectively reduced. This is because it can be made smaller.
That is, it is possible to effectively suppress the silica particles in the low refractive index layer from being melted or dropped by the etching treatment.

More specifically, as shown in FIG. 1A, when the value of the porosity in the low refractive index layer 2a is large, the existence ratio of the matrix portion made of the resin increases, so that severe alkali treatment was performed. Even in this case, the silica fine particles are effectively protected by the matrix portion, and the melting or falling off can be effectively suppressed.
On the other hand, as shown in FIG. 1B, when the value of the porosity in the low-refractive-index layer 2a 'is small, the existence ratio of the matrix portion made of the resin becomes small. In addition, the silica fine particles are not sufficiently protected by the matrix portion, and are easily melted or dropped off.
Therefore, by setting the porosity to a value of 15% or more, which is a value proved by an experiment, even when an etching process including a severe alkali process is performed, a predetermined value required for the low refractive index layer is required. The refractive index can be effectively maintained, and the pattern shape of the transparent conductive layer can be stably made invisible.
Further, even when etching treatment including severe alkali treatment is performed, since the rate of change of voids in the low refractive index layer before and after the etching treatment can be effectively reduced, the low refractive index caused by silica fine particles can be reduced. Fine irregularities on the surface of the layer can also be effectively maintained.
Therefore, it is possible to maintain the wetting tension on the surface of the low-refractive-index layer in a predetermined range, and obtain a predetermined adhesive force to the transparent conductive layer or the like required for the low-refractive-index layer.

On the other hand, when the porosity is excessively large, it is difficult to sufficiently lower the refractive index of the low refractive index layer, or it is difficult to form sufficient surface irregularities on the surface of the low refractive index layer. In some cases, it may be difficult to obtain a predetermined adhesion to a transparent conductive layer or the like.
Therefore, it is more preferable that the ratio of the voids on which the silica fine particles are not present on the exposed surface side of the low refractive index layer, that is, the porosity is set to a value within the range of 20 to 70%, and a value within the range of 22 to 40% More preferably,

The porosity described above is obtained, for example, by obtaining a reflected electron image on the exposed surface side of the low refractive index layer using a scanning electron microscope, and binarizing the obtained reflected electron image using image processing software. It is preferable to measure the ratio of voids in which silica fine particles are not present, that is, the porosity.
Alternatively, a backscattered electron image on the exposed surface side of the low refractive index layer is obtained using a scanning electron microscope, and the obtained backscattered electron image is enlarged and copied and printed out. The area of the void where no is present can be cut with scissors, and the porosity can be measured from the weight of the cut paper.
Note that the definition of the voids in the present invention is “a region where the silica fine particles do not exist, and a region where the diameter of the circle is 0.2 μm or more when the largest circle inscribed in the region is drawn”. I do.
Whether or not silica fine particles are present means that no silica fine particles are present in the film thickness direction at the plane position on the exposed surface.
Therefore, for example, even when the silica fine particles do not exist near the surface in the film thickness direction, if the silica fine particles exist near the bottom surface in the film thickness direction, “the silica fine particles exist” at the plane position. Is determined.

Further, the porosity increase rate (%) in the low refractive index layer before and after the transparent conductive layer forming laminate was immersed in a 5% by weight aqueous sodium hydroxide solution heated to 40 ° C. for 5 minutes and subjected to alkali treatment. That is, it is preferable to set the void increase rate (%) to a value of 26% or less.
The reason for this is that by setting the void increase rate to a value of 26% or less, it is possible to more reliably improve the etching resistance to etching processing including severe alkali processing.
That is, when the void increase rate exceeds 26%, it may be difficult to effectively suppress melting or falling off of the silica fine particles in the low refractive index layer by the etching treatment. That's why. On the other hand, the lower limit of the rate of increase in voids is preferably 0%. However, when the value is small, it is difficult to sufficiently lower the refractive index of the low refractive index layer, or it is difficult to form sufficient surface irregularities on the surface of the low refractive index layer, and it is difficult to form the transparent conductive layer or the like. In some cases, it may be difficult to obtain a predetermined adhesiveness to the object.
Therefore, the rate of increase of the porosity in the low refractive index layer before and after the transparent conductive layer forming laminate is immersed in a 5% by weight aqueous sodium hydroxide solution heated at 40 ° C. for 5 minutes and subjected to alkali treatment, that is, the porosity The increase rate is more preferably set to a value in the range of 10 to 25%, and further preferably to a value in the range of 19 to 24%.

(2) -6 Surface Free Energy The surface free energy of the low refractive index layer measured at 23 ° C. in accordance with JIS K 6768 is preferably set to a value of 37 mN / m or more.
The reason for this is that by setting the surface free energy on the exposed surface of the low refractive index layer to a value within the above range, while improving the etching resistance, a predetermined value for the transparent conductive layer or the like required for the low refractive index layer is obtained. This is because adhesion can be obtained more effectively.
That is, if the surface free energy is less than 37 mN / m, it may be difficult to obtain a predetermined adhesion to a transparent conductive layer or the like. On the other hand, when the surface free energy is excessively large, the adhesion to the protective film laminated on the transparent conductive layer forming laminate for surface protection becomes excessively strong, and work in the protective film peeling step is performed. This may lead to a decrease in efficiency.
Therefore, it is more preferable to set the surface free energy of the exposed surface of the low refractive index layer measured according to JIS K 6768 to a value within a range of 40 to 65 mN / m, and a value within a range of 45 to 60 mN / m. More preferably, it is set to a value.

4. Method for Producing Laminate for Forming Transparent Conductive Layer The laminate for forming a transparent conductive layer of the present invention can be obtained, for example, by a method comprising the following steps (a) and (b).
(A) Step of forming a hard coat layer on both sides of a base film (b) Step of forming an optical adjustment layer on one hard coat layer Hereinafter, portions overlapping with the above contents are omitted, and different portions are omitted. Only the details will be described.
The laminate for forming a transparent conductive layer of the present invention does not require a hard coat layer as an essential component, but in the following description, a case in which a hard coat layer is formed will be described as an example.

(1) Step (a): Step of Forming a Hard Coat Layer The above-described composition for forming a hard coat layer is applied to both surfaces of a base film by a conventionally known method to form a coating film, and then dried. The hard coat layer is formed by irradiating this with an active energy ray to cure the coating film.
Examples of the method of applying the composition for forming a hard coat layer include a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.

The drying is preferably performed at 60 to 150 ° C. for about 10 seconds to 10 minutes.
Furthermore, examples of the active energy ray include an ultraviolet ray and an electron beam.
Examples of the ultraviolet light source include a high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, and a xenon lamp, and the irradiation amount is usually preferably 100 to 500 mJ / cm ² .
On the other hand, examples of the electron beam light source include an electron beam accelerator, and the irradiation amount is usually preferably 150 to 350 kV.

(2) Step (b): Step of Forming Optical Adjustment Layer Next, a high refractive index layer is formed on the formed hard coat layer (or directly on the base film when the hard coat layer is not formed). .
That is, the high refractive index layer is applied and dried in the same manner as the formation of the hard coat layer on the base film, and cured by irradiating with an active energy ray. It can be formed by performing.
Next, a low refractive index layer is further formed on the formed high refractive index layer.
That is, the low-refractive-index layer is applied and dried in the same manner as forming the hard-coat layer on the base film, and cured by irradiating with an active energy ray. It can be formed by performing.

[Second embodiment]
As shown in FIG. 3, a second embodiment of the present invention is a transparent conductive film 100 in which an optical adjustment layer 2 and a transparent conductive layer 1 are sequentially laminated on at least one surface of a base film 4. Wherein the optical adjustment layer 2 has, from the side of the base film 4, a high refractive index layer 2b having a refractive index of 1.6 or more and a low refractive index having a refractive index of 1.45 or less. The low refractive index layer 2a contains silica fine particles, and the ratio of voids where no silica fine particles are present on the exposed surface side of the low refractive index layer 2a is 15% or more. The transparent conductive film 100 is characterized in that the value is a value.
Hereinafter, in the second embodiment of the present invention, the same parts as those described above will be omitted, and only different parts will be described in detail.

1. Transparent Conductive Layer (1) Material In the transparent conductive film of the present invention, the material of the transparent conductive layer is not particularly limited as long as it has both transparency and conductivity. Examples include indium, zinc oxide, tin oxide, indium tin oxide (ITO), tin antimony oxide, zinc aluminum oxide, and indium zinc oxide.
In particular, it is preferable to use ITO as a material.
This is because ITO can form a transparent conductive layer having excellent transparency and conductivity by adopting appropriate film forming conditions.

(2) Pattern Shape Further, it is preferable that the transparent conductive layer is formed in a pattern shape such as a line shape or a lattice shape by etching.
In the above-described pattern shape, it is preferable that the line width of the portion where the transparent conductive layer is present is substantially equal to the line width of the portion where the transparent conductive layer is not present.
Further, the line width is usually 0.1 to 10 mm, preferably 0.2 to 5 mm, and particularly preferably 0.5 to 2 mm.
Note that the line width in the above-described line shape or grid shape is not limited to being constant, and, for example, a line having a shape required for a capacitive touch panel can be freely selected.
Specifically, a pattern shape in which a rhombus portion and a line portion are repeatedly connected, and the like are included, and such a pattern shape is also included in the category of “line shape”.

(3) Film thickness The thickness of the transparent conductive layer is preferably from 5 to 500 nm.
The reason for this is that if the thickness of the transparent conductive layer is less than 5 nm, not only the transparent conductive layer becomes brittle, but also sufficient conductivity may not be obtained. On the other hand, when the thickness of the transparent conductive layer exceeds 500 nm, the color due to the transparent conductive layer becomes strong, and the pattern shape may be easily recognized.
Therefore, the thickness of the transparent conductive layer is more preferably from 15 to 250 nm, further preferably from 20 to 100 nm.

2. Method for Producing Transparent Conductive Film The optical adjustment layer obtained in step (b) in the method for producing a laminate for forming a transparent conductive layer described above is subjected to a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, and a spray method. A transparent conductive film can be obtained by forming a transparent conductive layer by a known method such as a method and a sol-gel method.
Examples of the sputtering method include a normal sputtering method using a compound and a reactive sputtering method using a metal target.
At this time, it is also preferable to introduce oxygen, nitrogen, water vapor, or the like as a reactive gas, or to use ozone addition or ion assist in combination.
Further, after the transparent conductive layer is formed as described above, a resist mask having a predetermined pattern is formed by a photolithography method, and then an etching process is performed by a known method to form a linear pattern or the like. can do.
In addition, as the etching solution, an aqueous solution of an acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and the like are preferably exemplified.
In addition, from the viewpoint of speeding up the etching process, the solution used in the alkali process for removing the remaining photoresist, which is the final step of the etching process, has a solution temperature of 10 to 50 ° C., a concentration of 1 to 10% by weight, It is preferable to use a strong base aqueous solution having a pH of 13.4 to 14.4.
Suitable strong bases include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, calcium hydroxide, strontium hydroxide, and hydroxide. Barium, europium (II) hydroxide, thallium (I) hydroxide, guanidine and the like can be mentioned.

Further, in order to increase the crystallinity of the transparent conductive layer and lower the resistivity, it is preferable to perform an annealing process by providing an annealing step.
That is, it is preferable to expose the obtained transparent conductive film at a temperature of 130 to 180 ° C. for 0.5 to 2 hours.

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

[Example 1]
1. Preparation of Composition for Forming Hard Coat Layer In a container, 60 parts by weight of an ultraviolet curable resin containing amorphous silica (manufactured by Showa Denko KK, vinylol FC-1000) (the pure content excluding the diluting solvent is represented. The same applies hereinafter). ), 45 parts by weight of the silica of the amorphous silica dispersion, 0.03 parts by weight of a crosslinked acrylic copolymer resin (Techpolymer XX-27LA, manufactured by Sekisui Chemical Co., Ltd.), and a silicone leveling agent. (BKY-3550, manufactured by BIC-Chemie Japan KK) and 0.03 parts by weight, and then a solvent was added and uniformly mixed to obtain a composition for forming a hard coat layer having a solid concentration of 22% by weight. Prepared.

2. Preparation of Composition for Forming High Refractive Index Layer In a container, 100 parts by weight of an ultraviolet curable resin (manufactured by Dainichi Seika Kogyo Co., Ltd., Seika Beam EXF-01L (NS)) and a zirconium oxide dispersion (CIK Nanotech ( Co., Ltd., 200 parts by weight of ZRMIBK15WT% -F85), 0.05 parts by weight of an acrylic leveling agent (BYK-355, manufactured by BYK Japan KK), and a photopolymerization initiator (BASF Japan Co., Ltd.) And 3 parts by weight of Irgacure 907) were added thereto, and a solvent was added thereto and uniformly mixed to prepare a composition for forming a high refractive index layer having a solid content concentration of 1% by weight.

3. Preparation of composition for forming low refractive index layer In a container, an active energy ray-curable resin containing a water-repellent resin as the component (A), silica fine particles as the component (B), and a silica fine particle as the component (C) After containing the leveling agent and the photopolymerization initiator as the component (D) in the following composition, a solvent is added and uniformly mixed to obtain a composition for forming a low refractive index layer having a solid concentration of 1% by weight. Prepared.
In addition, the compounding quantity in the following composition represents the pure content except the diluting solvent.
Component (A): UV curable acrylic resin containing fluorine resin
100 parts by weight (Type of fluororesin: reactive fluoroacrylic resin, content of fluororesin: 80% by weight, surface free energy of cured resin coating film of fluororesin alone: 25 mN / m)
Component (B): 100 parts by weight of reactive hollow silica fine particles (volume average particle diameter (D50) 45 nm)
Component (C): silicone-based leveling agent 0.03 parts by weight (BYK-3550 manufactured by BYK Japan KK)
Component (D): 10 parts by weight of a photopolymerization initiator (IRGACURE 184, manufactured by BASF Japan K.K.)
The volume average particle diameter (D50) of the component (B) was measured by a laser diffraction / scattering particle size distribution analyzer.
Hereinafter, the photopolymerization initiator as the component (D) may be referred to as “Irgacure 184”.

4. Formation of Hard Coat Layer A polyester film (PET125KEL86W, manufactured by Teijin DuPont Co., Ltd.) having a 125 μm-thick adhesive layer was prepared as a base film.
Next, the composition for forming a hard coat layer was applied to the surface of the prepared base film using a wire bar # 8.
Next, after drying at 70 ° C. for 1 minute, the substrate film was irradiated with ultraviolet rays under an atmosphere using a UV irradiation apparatus (manufactured by GS Yuasa Corporation) under a nitrogen atmosphere under the following conditions. A hard coat layer was formed.
In addition, a hard coat layer was similarly formed on the opposite surface of the base film.
Light source: High pressure mercury lamp Illuminance: 150 mW / cm ²
Light intensity: 150 mJ / cm ²

5. Formation of High Refractive Index Layer Next, on one of the formed hard coat layers, a composition for forming a high refractive index was applied using a wire bar # 4.
Next, after drying at 50 ° C. for 1 minute, ultraviolet rays were irradiated under the same irradiation conditions as the hard coat layer using an ultraviolet irradiation apparatus (manufactured by GS Yuasa Corporation) under a nitrogen atmosphere, so that the hard coat layer was formed. A high refractive index layer having a thickness of 35 nm and a refractive index n _D = 1.65 was formed.

6. Formation of Low Refractive Index Layer Next, a composition for forming a low refractive index layer was applied on the formed high refractive index layer using a wire bar # 4.
Next, after drying at 50 ° C. for 1 minute, ultraviolet light was irradiated under a nitrogen atmosphere using a UV irradiation apparatus (manufactured by GS Yuasa Corporation) under the same irradiation conditions as the hard coat layer, and the high refractive index layer was A low-refractive-index layer having a thickness of 50 nm and a refractive index of n _D = 1.37 was formed thereon to obtain a laminate for forming a transparent conductive layer as shown in FIG.

7. Measurement of porosity On the exposed surface side of the low refractive index layer of the obtained laminate for forming a transparent conductive layer, the ratio of porosity in which no silica fine particles exist, that is, the porosity (%) was measured.
That is, using a field emission scanning electron microscope (FE-SEM) (S-4700, manufactured by Hitachi High-Technologies Corporation), the obtained transparent conductive layer was obtained under the conditions of an acceleration voltage of 10 kV and a measurement magnification of 5000 times. A reflected electron image (observation range: 450 × 575 μm ² ) on the exposed surface side of the low refractive index layer in the forming laminate was obtained.
Next, the obtained backscattered electron image was binarized using image processing software (Image Pro-plus, manufactured by Cybernetic Co., Ltd.), and the ratio of voids in which silica fine particles did not exist, that is, the porosity (%) was measured. However, the porosity was 24.1%.
FIG. 4A shows the obtained backscattered electron image.

8. Evaluation (1) Evaluation of etching resistance 1
The etching resistance of the obtained laminate for forming a transparent conductive layer was evaluated based on an increase rate (%) of a porosity (%) in the low refractive index layer (hereinafter, may be referred to as a “void increase rate”).
That is, the laminate for forming a transparent conductive layer is immersed in a 5% by weight aqueous solution of sodium hydroxide heated to 40 ° C. for 5 minutes and alkali-treated, and then the voids in the low refractive index layer under the same conditions as described above. The rate (%) was measured. FIG. 4B shows the obtained reflected electron image.
Next, the porosity (%) after the alkali treatment was divided by the porosity (%) before the alkali treatment to calculate the porosity increase rate (%). Table 1 shows the obtained results.
If the rate of increase in voids is 26% or less, it can be determined that the layer has practically excellent etching resistance.

(2) Evaluation of etching resistance 2
The etching resistance of the obtained laminate for forming a transparent conductive layer is determined by the change amount (%) of the reflectance (%) of the laminate for forming a transparent conductive layer (hereinafter, may be referred to as “reflectance change amount”). Was evaluated.
That is, the reflectance (%) (low-refractive-index layer side) of the obtained laminate for forming a transparent conductive layer was measured using an ultraviolet-visible-near-infrared (UV-vis-NIR) spectrophotometer (manufactured by Shimadzu Corporation, UV -3600) under the following conditions: reflection angle: 8 °, sampling pitch: 1 nm, measurement mode: single.
Next, the laminate for forming a transparent conductive layer is immersed in a 5% by weight aqueous sodium hydroxide solution heated to 40 ° C. for 5 minutes to carry out alkali treatment, and the reflectance (%) is measured under the same conditions as described above. It was measured.
Next, the reflectance change (%) was calculated by subtracting the reflectance (%) after the alkali treatment from the reflectance (%) before the alkali treatment . Table 1 shows the obtained results.
If the change in reflectance is 0.5% or less, it can be determined that the film has excellent etching resistance in practical use.
The reason why the etching resistance can be evaluated based on the reflectance change amount (%) is that the reflectance of the low refractive index layer changes when the film thickness or the refractive index or both of the low refractive index layer changes by the etching process. is there.

(3) Evaluation of etching resistance 3
The etching resistance of the obtained laminate for forming a transparent conductive layer is defined as the variation (nm) of the arithmetic average surface roughness Ra (nm) on the exposed surface of the low refractive index layer (hereinafter referred to as “Ra variation”). There is).
That is, using a light interference type surface roughness meter (WYKO NT-1100, manufactured by Veeco Co., Ltd.) under the conditions of Measurement Type: PSI (Infinite Scan), Objective: 10.0X, and FOV: 1.0X. The arithmetic average roughness Ra (nm) on the exposed surface of the low refractive index layer in the obtained laminate for forming a transparent conductive layer was measured.
Next, data analysis was performed using Terms Removal: Tilt Only (Plane Fit) and Window Filtering: None, and the arithmetic average surface roughness Ra (nm) was measured.
Next, the obtained laminate for forming a transparent conductive layer is immersed in a 5% by weight aqueous solution of sodium hydroxide heated to 40 ° C. for 5 minutes to carry out alkali treatment, and then subjected to the arithmetic mean surface treatment under the same conditions as described above. The roughness Ra (nm) was measured.
Next, the arithmetic average surface roughness Ra (nm) after the alkali treatment was subtracted from the arithmetic average surface roughness Ra (nm) before the alkali treatment to calculate the amount of Ra change (nm) . Table 1 shows the obtained results.
In addition, if the arithmetic average surface roughness change amount is less than 10 nm , it can be judged that it has excellent etching resistance in practical use.

(4) Evaluation of pattern visibility A patterned transparent conductive layer was formed on the surface of the low refractive index layer of the obtained laminate for forming a transparent conductive layer, and the visibility was evaluated.
That is, after the obtained laminate for forming a transparent conductive layer is cut into a length of 90 mm and a width of 90 mm, sputtering is performed using an ITO target (tin oxide 10% by weight, indium oxide 90% by weight) to form a layer on the low refractive index layer. A transparent conductive layer having a square shape of 60 mm long × 60 mm wide and a thickness of 30 nm was formed in the center of the sample.
Next, a photoresist film patterned in a lattice pattern was formed on the surface of the obtained transparent conductive layer.
Next, etching treatment was performed by immersion in 10% by weight of hydrochloric acid at room temperature for 1 minute to pattern the transparent conductive layer into a lattice.
Next, the substrate is immersed in a 5% by weight aqueous solution of sodium hydroxide heated to 40 ° C. for 5 minutes to carry out an alkali treatment to remove the photoresist film on the transparent conductive layer and to form a transparent conductive layer having a patterned transparent conductive layer. A functional film was obtained.
The transparent conductive film had a transparent conductive layer of 30 nm having a pattern shape in which a square space having a side of 2 mm was partitioned into a lattice by a line portion made of ITO having a line width of 2 mm.
Next, the obtained transparent conductive film is placed at a position 1 m from the white fluorescent lamp, and the transparent conductive film reflects the white fluorescent lamp, on the same side where the white fluorescent lamp is placed. The pattern shape of the transparent conductive layer was visually observed from a position 30 cm from the transparent conductive film in the above, and evaluated according to the following criteria . Table 1 shows the obtained results.
◎: The pattern shape of the transparent conductive layer is not visually recognized ○: The pattern shape of the transparent conductive layer is slightly recognized ×: The pattern shape of the transparent conductive layer is visually recognized

(5) Evaluation of Surface Free Energy The obtained transparent conductive layer forming laminate was evaluated for surface free energy (mN / m) measured at 23 ° C. in accordance with JIS K 6768.
That is, a wet tension test solution having a predetermined surface tension is applied to the obtained transparent conductive layer forming laminate on the upper surface of the low refractive index layer, which is the outermost layer, using a cotton swab so as to have a width of 10 mm and a length of 60 mm. did.
If the coating film of the wetting tension test liquid is not interrupted for 2 seconds, it is judged that the surface free energy is acceptable, and the same operation is sequentially performed using the wetting tension test liquid having a higher surface tension. This was repeated until the coating film of No. was interrupted within 2 seconds, and the highest surface free energy that passed was taken as the measurement result. Table 1 shows the obtained results.
It should be noted that the wetting tension and the surface free energy are synonymous in thermodynamics, and therefore, in the present invention, the wetting tension is described as the surface free energy.

[Example 2 and Comparative Examples 1-2]
In Example 2 and Comparative Examples 1 and 2, when preparing the composition for forming a low refractive index layer, the blending amount of the reactive hollow silica fine particles (volume average particle diameter (D50) 45 nm) is shown in Table 1. The same procedure as in Example 1 was repeated except that the porosity of the low refractive index layer of the obtained laminate for forming a transparent conductive layer was changed as described in Table 1 by changing the porosity of the laminate for forming a transparent conductive layer. Manufactured and evaluated. Table 1 shows the obtained results.
FIG. 5A is a backscattered electron image of the exposed surface of the low refractive index layer in the transparent conductive layer forming laminate before the alkali treatment in Comparative Example 1, and FIG. It is a reflected electron image of the exposed surface of the low refractive index layer in the transparent conductive layer forming laminate after the alkali treatment.

As described above in detail, according to the present invention, silica is contained in the low refractive index layer, which is the outermost layer of the transparent conductive layer forming laminate, and silica fine particles on the exposed surface side of the low refractive index layer. By setting the ratio of voids in which no is present to a value of 15% or more, a laminated body for forming a transparent conductive layer having excellent etching resistance in a low refractive index layer can be obtained.
As a result, the laminate for forming a transparent conductive layer can stably make the pattern shape of the transparent conductive layer invisible even after severe etching treatment, and has excellent adhesion between the transparent conductive layer and the like. Can be obtained.
Therefore, the laminate for forming a transparent conductive layer of the present invention and the transparent conductive film using the same are expected to significantly contribute to improving the quality of a touch panel.

1: transparent conductive layer, 2: optical adjustment layer, 2a: low refractive index layer, 2b: high refractive index layer, 3: hard coat layer, 4: base film, 10: laminate for forming a transparent conductive layer, 20: Silica fine particles, 22: void, 100: transparent conductive film,

Claims (8)

A transparent conductive layer forming laminate having an optical adjustment layer on at least one surface of the substrate film,
Hard coat layer is provided on both sides or one side of the base film,
The optical adjustment layer sequentially laminates, from the base film side, 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. With doing
The low refractive index layer contains silica fine particles, and
On the exposed surface side of the low refractive index layer, the ratio of voids where the silica fine particles are not present is set to a value of 15% or more ,
A laminate for forming a transparent conductive layer, wherein a surface free energy of the low refractive index layer is 37 mN / m or more .   The laminate for forming a transparent conductive layer according to claim 1, wherein a volume average particle diameter (D50) of the silica fine particles is set to a value within a range of 20 to 70 nm.   The laminate for forming a transparent conductive layer according to claim 1, wherein the silica fine particles are hollow silica fine particles.   The laminate for forming a transparent conductive layer according to any one of claims 1 to 3, wherein the silica fine particles are reactive silica fine particles.   The transparent conductive layer forming laminate according to any one of claims 1 to 4, wherein a matrix portion in the low refractive index layer contains a cured product of an active energy ray-curable resin.   The transparent conductive layer forming laminate according to any one of claims 1 to 5, wherein the low refractive index layer has a thickness in a range of 20 to 80 nm. An optical adjustment layer on at least one surface of the substrate film, and a transparent conductive layer, a transparent conductive film obtained by sequentially laminating,
A hard coat layer is provided on both sides or one side of the base film,
The optical adjustment layer sequentially laminates, from the base film side, 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. With doing
The low refractive index layer contains silica fine particles, and
On the exposed surface side of the low refractive index layer, the ratio of voids where the silica fine particles are not present is set to a value of 15% or more ,
A transparent conductive film, wherein the surface free energy of the low refractive index layer is 37 mN / m or more . The transparent conductive film according to claim 7, wherein the transparent conductive layer is patterned by etching.