JP5651106B2 - Transparent conductive film - Google Patents

Description

  The present invention relates to a transparent conductive film. More specifically, the present invention has electrical characteristics and transmittance equivalent to those of ITO without using tin-doped indium oxide (ITO) using indium, which is an expensive rare metal, and is used for display. The present invention relates to a transparent conductive film which is suitable as an electrode for a touch panel such as a transparent electrode.

Conventionally, tin-doped indium oxide (ITO), tin oxide, indium oxide, zinc oxide, aluminum-doped zinc oxide, and the like are known as inorganic conductive materials, and among these, transparency and electrical properties are known. Transparent conductive films using particularly excellent ITO are widely used as transparent electrodes such as liquid crystal displays and transparent touch panels.
Such transparent conductive films are well known in which an ITO film is provided on the surface of a transparent film such as a polyethylene terephthalate film or a triacetylcellulose film by a dry process such as vacuum deposition, sputtering, or ion plating. (For example, see Patent Documents 1 and 2).
By the way, about 90% of touch panels currently employ a resistive film system. The resistive film type touch panel generally includes a touch side plastic substrate in which a transparent conductive thin film such as an ITO film is laminated on one side of a transparent plastic base material, and a transparent conductive thin film such as an ITO film on one side of a transparent base material such as glass. And a display-side transparent substrate laminated with each other through an insulating spacer so that the transparent conductive thin films face each other.
Then, the input is performed by pressing the touch input surface of the touch side plastic substrate (referred to as the surface opposite to the transparent conductive thin film side) with a pen or a finger, and the transparent conductive thin film on the touch side plastic substrate and the display side. The contact is made with the transparent conductive thin film of the transparent substrate.
However, in such a resistive film type touch panel, the touch side plastic is obtained by repeating the input operation, that is, by repeating the contact between the transparent conductive thin film of the touch side plastic substrate and the transparent conductive thin film of the display side transparent substrate. Problems arise such that the transparent conductive thin film of the substrate is worn, cracks are generated, and further, the substrate is peeled off from the substrate. Therefore, in order to solve such problems, generally, a hard coat layer made of a cured resin is provided between the transparent plastic substrate and the transparent conductive thin film. Further, it is often performed to provide a hard coat layer on the surface of the transparent plastic substrate opposite to the transparent conductive thin film.
However, ITO used as a transparent conductive thin film on such a transparent conductive film or transparent conductive plastic substrate is expensive because indium, which is a rare metal, is used, and a special process is required for forming the thin film. Moreover, since it is hard and brittle, there exists a problem that handling is bad. Therefore, in order to solve these problems, use of a conductive organic polymer compound has been studied (see, for example, Patent Documents 3 and 4).
However, although it is possible for conductive organic polymer compounds to obtain electrical properties equivalent to those of ITO, it is inevitable that the transmittance of the obtained conductive film, etc. is lowered, and it has not yet been put into practical use. It is.
As described above, the conductive organic polymer compound has a lower transmittance than that of ITO when an electrical property equivalent to that of ITO is obtained, and the electrical property is deteriorated when the transmittance is increased (electrical property). The transmittance is dependent on the film thickness). When the transmittance is low, the visibility as a display may be reduced.

JP 2006-216266 A JP 2007-133839 A Japanese Patent Application Laid-Open No. 2002-179954 WO2006 / 082944 pamphlet

  The present invention has been made under such circumstances, and has the same electrical characteristics and transmittance as ITO without using ITO using indium, which is an expensive rare metal, and is a transparent electrode for display. In particular, the object is to provide a transparent conductive film suitable as an electrode for a touch panel.

As a result of intensive studies to achieve the above object, the present inventors have found that a high refractive index optical material containing a specific resin and metal oxide particles having an average particle size of a certain value or less on a base film. By providing an adjustment layer and a conductive organic polymer layer having a refractive index lower than that of the optical adjustment layer on the adjustment layer, the reflection can be suppressed and the transmittance can be improved while maintaining the electrical characteristics. It was found that a transparent conductive film having electrical characteristics and transmittance equivalent to those of a conductive film using ITO was obtained. The present invention has been completed based on such findings.
That is, the present invention
(1) A transparent conductive film in which a layer (A) and a layer (B) are sequentially laminated on a base film, wherein the layer (A) is a thermoplastic resin and / or an active energy ray-curable resin. a binder resin, an optical adjustment layer including the average particle diameter 200nm or less of the metal oxide particles, as the metal oxide particles comprise titanium oxide particles and / or antimony-doped tin oxide particles, and wherein (B) The layer is a conductive organic polymer layer, the refractive index of the optical adjustment layer (A) is 1.65 to 1.90, the surface resistivity is 300 to 800 Ω / □, and the total light transmittance is 86% or more of a transparent conductive film,
( 2 ) The transparent conductive film according to ( 1 ) above, wherein the reflectance at a wavelength of 550 nm on the surface of the conductive organic polymer layer is 5% or less,
( 3 ) The transparent conductive film according to (1) or (2) above, wherein the refractive index of the conductive organic polymer layer (B) is lower than the refractive index of the optical adjustment layer (A),
( 4 ) (B) The above-mentioned (1) to ( 3 ), wherein the conductive organic polymer compound constituting the conductive organic polymer layer is at least one selected from polythiophene, polyaniline and polypyrrole compounds. ) Transparent conductive film according to any one of items
( 5 ) (A) Titanium oxide particles and / or antimony-doped tin oxide particles having an average particle diameter of 200 nm or less with respect to 100 parts by mass of the binder resin of thermoplastic resin and / or active energy ray-curable resin as the optical adjustment layer. The transparent conductive film according to any one of (1) to ( 4 ), comprising 1 to 700 parts by mass of
( 6 ) The transparent conductive film according to any one of (1) to ( 5 ) above, wherein a hard coat layer is provided on the back surface of the base film, and ( 7 ) the base film, and (A) The transparent conductive film according to any one of (1) to ( 6 ), wherein a hard coat layer is provided between the optical adjustment layer and
Is to provide.

  According to the present invention, without using ITO using indium which is an expensive rare metal, it has the same electrical characteristics and transmittance as ITO, and is suitable for use as a transparent electrode for display, particularly as a touch panel electrode. A conductive film can be provided.

  FIG. 1 is a schematic cross-sectional view showing the structure of an example of the transparent conductive film of the present invention, FIG. 2 is a schematic cross-sectional view showing the structure of another example of the transparent conductive film of the present invention, FIG. 3 is a schematic cross-sectional view showing the structure of another different example of the transparent conductive film of the present invention, FIG. 4 is a schematic cross-sectional view showing the configuration of still another example of the transparent conductive film of the present invention. In the figure, reference numeral 1 is a base film, 2 is an optical adjustment layer, 3 is a conductive organic polymer layer, 4-a and 4-b are hard coat layers, 10, 20, 30 and 40 are transparent conductive films. .

［ポリ（３，４−エチレンジオキシチオフェン）ポリ（スチレンスルホン酸）水性分散体］
上記ポリアルキレンジオキシチオフェンとポリスチレンスルホネートとの複合体またはその配合品の市販品としては、例えば、「ＳＥＰＬＥＧＹＤＡ」［商品名、信越ポリマー（株）製］や、「ＣＬＥＶＩＯＳ Ｐ」［商品名、Ｈ．Ｃ．Ｓｔａｒｃｋ社製］などが挙げられる。
これらの導電性有機高分子化合物は、１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。
Ｓｔｅｐｈａｎ Ｋｉｒｃｈｍｅｙｅｒ ＆ Ｋｎｕｄ Ｒｅｕｔｅｒ，Ｊ．Ｍａｔｅｒ．Ｃｈｅｍ．，２００５，１５，２０７７−２０８８ Ｈ．Ｃ．Ｓｔａｒｃｋ社パンフレット、Ｐｒｏｄｕｃｔ Ｉｎｆｏｒｍａｔｉｏｎ The transparent conductive film of the present invention is characterized in that (A) an optical adjustment layer and (B) a conductive organic polymer layer having the following properties are sequentially laminated on a base film.
[Base film]
There is no restriction | limiting in particular in the base film used in the transparent conductive film of this invention, It can select and use suitably from well-known plastic films as a base material of the film for conventional optics. Examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene films, polypropylene films, cellophane, diacetyl cellulose films, triacetyl cellulose films, acetyl cellulose butyrate films, and polychlorinated. Vinyl film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, polyetherimide film , Polyimide film, fluororesin film, Li amide film, acrylic resin film, norbornene resin film, a cycloolefin resin film.
These base films may be either transparent or translucent, may be colored, or may be uncolored, and may be appropriately selected depending on the application.
The thickness of these base films is not particularly limited and is appropriately selected depending on the situation, but is usually about 15 to 300 μm, preferably 30 to 200 μm, more preferably 50 to 200 μm. Moreover, this base film can be surface-treated by an oxidation method, a concavo-convex method, or the like on one side or both sides as desired for the purpose of improving adhesion to a layer provided on the surface. Examples of the oxidation method include corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and examples of the unevenness method include a sand blast method, a solvent, and the like. Treatment methods and the like. These surface treatment methods are appropriately selected according to the type of the base film, but generally, the corona discharge treatment method is preferably used from the viewpoints of effects and operability.
[(A) Optical adjustment layer]
In the transparent conductive film of the present invention, an optical adjustment layer is provided as the (A) layer on the above-mentioned base film. This optical adjustment layer is a layer containing at least one binder resin selected from thermoplastic resins, thermosetting resins and active energy ray curable resins, and metal oxide particles having an average particle size of 200 nm or less. .
The optical adjustment layer reduces the surface reflectance by making the refractive index higher than the refractive index of a conductive organic polymer layer (B) described later provided on the layer. Therefore, it has the function of increasing the total light transmittance and improving the transparency.
(Binder resin)
In the optical adjustment layer, at least one resin selected from thermoplastic resins, thermosetting resins, and active energy ray curable resins is used as the binder resin.
<Thermoplastic resin>
As the thermoplastic resin, those having transparency are preferable, for example, aromatic polyester-based or aliphatic polyester-based resin, polyester urethane-based resin, polyolefin-based resin such as polyethylene, polypropylene, polymethylpentene, polycycloolefin, and diacetyl. Cellulose resins such as cellulose, triacetyl cellulose, acetyl cellulose butyrate, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl alcohol resins, polystyrene resins, polycarbonate resins, acrylic resins, polyamide resins, etc. Can be mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.
<Thermosetting resin>
The thermosetting resin refers to a cured product of a thermosetting compound that is polymerized, crosslinked, and cured by applying heat. As the thermosetting resin, for example, a thermosetting addition reaction type silicone resin can be used. Examples of the addition reaction type silicone resin include at least one selected from polyorganosiloxanes having an alkenyl group as a functional group in the molecule. Preferred examples of the polyorganosiloxane having an alkenyl group as a functional group in the molecule include polydimethylsiloxane having a vinyl group as a functional group, polydimethylsiloxane having a hexenyl group as a functional group, and a mixture thereof. .
Examples of the crosslinking agent include polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule, specifically, a dimethylhydrogensiloxy group end-capped dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy. Examples thereof include a group-end-capped dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-end-capped poly (methylhydrogensiloxane), and poly (hydrogensilsesquioxane). The usage-amount of a crosslinking agent is selected in the range of 0.1-100 mass parts normally with respect to 100 mass parts of addition reaction type silicone resins, Preferably it is 0.3-50 mass parts.
As the catalyst, a platinum compound is usually used. Examples of the platinum compound include fine platinum, fine platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, rhodium catalyst, and the like. . The usage-amount of a catalyst is about 1-1000 ppm as a platinum-type metal with respect to the total amount of an addition reaction type silicone resin and a crosslinking agent.
This thermosetting addition reaction type silicone resin can be cured by heating to a temperature of about 70 to 160 ° C.
<Active energy ray curable resin>
An active energy ray-curable resin has an energy quantum in an electromagnetic wave or a charged particle beam, that is, an active energy ray-curing property that polymerizes, crosslinks, and cures when irradiated with an energy ray such as an ultraviolet ray or an electron beam. It refers to the cured product of the compound.
Examples of such active energy ray-curable compounds include radical polymerization type photopolymerizable prepolymers and / or photopolymerizable monomers. Examples of the radical polymerization type photopolymerizable prepolymer include polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate. These photopolymerizable prepolymers may be used alone or in combination of two or more.
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, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified diphosphate ( (Meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) Chryrate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta Examples include polyfunctional acrylates such as (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate. These photopolymerizable monomers may be used alone or in combination of two or more thereof, or may be used in combination with the photopolymerizable prepolymer.
In the present invention, the photopolymerizable prepolymer and / or photopolymerizable monomer may be used in combination with various conventionally known photopolymerization initiators as desired.
The blending amount is usually selected in the range of 0.2 to 10 parts by mass with respect to 100 parts by mass of the photopolymerizable prepolymer and / or photopolymerizable monomer.
Such an active energy ray-curable compound containing a photopolymerizable prepolymer and / or a photopolymerizable monomer and optionally a photopolymerization initiator can be cured by irradiation with active energy rays such as ultraviolet rays. In addition, when irradiating an electron beam as an active energy ray, a photoinitiator is not required.
In the present invention, as the binder resin constituting the optical adjustment layer of the (A) layer, a thermoplastic resin and an active energy ray curable resin are preferable among those exemplified above. A thermosetting resin using an addition reaction type silicone resin is expensive and has a problem in adhesion to the conductive organic polymer layer of the (B) layer provided thereon. In addition, since the optical adjustment layer is coated with a thin film, the active energy ray (ultraviolet ray) curable resin is particularly preferably a thermoplastic resin because it may be affected by oxygen inhibition during curing.
(Metal oxide particles)
In the optical adjustment layer, metal oxide particles are used for adjusting the refractive index. Examples of the metal oxide particles include high refractive index metal oxide particles such as titanium oxide, tantalum oxide, zirconium oxide, niobium oxide, hafnium oxide, tin oxide, and antimony-doped tin oxide (ATO). Since the said metal oxide is used for refractive index adjustment, in order to acquire electroconductivity, compared with the conventional thing used as a conductive thin film on a film, the usage-amount of a metal oxide is as much as possible.
The metal oxide particles are required to have an average particle size of 200 nm or less. When the average particle diameter exceeds 200 nm, the haze value is increased and the transparency is lowered. A preferable average particle diameter is 150 nm or less. Moreover, the lower limit is about 2 nm from the viewpoint of manufacturability.
The average particle size of the metal oxide particles is a value measured by a dynamic scattering method.
Moreover, the compounding amount of the metal oxide particles is preferably about 1 to 700 parts by mass with respect to 100 parts by mass of the binder resin described above. When the amount is less than 1 part by mass, it is difficult to improve the refractive index. When the amount exceeds 700 parts by mass, the amount of metal oxide is large and the coating film becomes weak, and the metal oxide may fall off. A more preferable blending amount is 10 to 600 parts by mass, and more preferably 100 to 400 parts by mass.
When the refractive index of the optical adjustment layer is not higher than the refractive index of the conductive organic polymer layer (B) provided thereon, a sufficient antireflection effect cannot be obtained, and the total light transmittance I cannot expect improvement. The metal oxide particles may be appropriately selected in consideration of refractive index, transparency, price, etc., and titanium oxide particles, tin oxide particles, and antimony-doped tin oxide particles are suitable, and particularly titanium oxide particles and / or Antimony-doped tin oxide particles are preferred.
(Formation of optical adjustment layer)
In the transparent conductive film of the present invention, an optical adjustment layer is provided as the (A) layer on the above-described base film. For this purpose, first, an optical adjustment layer forming coating solution is prepared.
In a suitable medium, at least one selected from a thermoplastic resin, a thermosetting resin and an active energy ray curable resin as a binder resin, and metal oxide particles are dissolved or dispersed at a predetermined ratio. An optical adjustment layer forming coating solution having a solid content concentration of about 0.1 to 10% by mass is prepared.
Next, on the base film, the above-mentioned coating liquid for forming an optical adjustment layer is formed using a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. Then, it is applied so as to have a predetermined dry thickness, and is dried at about 70 to 110 ° C. for about 30 seconds to 2 minutes. Furthermore, if necessary, curing is performed by heat curing or irradiation with active energy rays. When only a thermoplastic resin is used as the binder resin, only a drying process may be performed, and it is not necessary to perform a curing process by thermal curing or irradiation with an active energy ray, and the operation is simple and preferable.
In this manner, an optical adjustment layer having a thickness of about 50 to 500 nm, preferably 100 to 200 nm can be formed. The refractive index of this optical adjustment layer is usually about 1.60 to 2.00, preferably 1.65 to 1.90.
[(B) Conductive organic polymer layer]
In the transparent conductive film of the present invention, a conductive organic polymer layer is provided as the (B) layer on the optical adjustment layer of the (A) layer formed as described above.
(Conductive organic polymer compound)
The conductive organic polymer compound constituting the conductive organic polymer layer of the (B) layer is not particularly limited as long as it is conductive and can be dissolved or dispersed in an appropriate solvent. For example, polyacetylene series such as trans-type polyacetylene, cis-type polyacetylene, and polydiacetylene; poly (phenylene) series such as poly (p-phenylene) and poly (m-phenylene); polythiophene, poly (3-alkylthiophene), poly ( 3-thiophene-β-ethanesulfonic acid), polythiophene systems such as polyalkylene dioxythiophene and polystyrene sulfonate complexes; polyaniline systems such as polyaniline, polymethylaniline, polymethoxyaniline; polypyrrole, poly-3-methylpyrrole, Polypyrrole, such as poly-3-octylpyrrole ; Poly (p- phenylene vinylene) such as poly (phenylene vinylene) system; poly (vinyl sulfide) system; poly (p- phenylene sulfide) system; poly (thienylene vinylene) compounds and the like are used. Among these, polythiophene-based, polyaniline-based, and polypyrrole-based compounds are preferable from the viewpoint of performance and availability, and polythiophene-based compounds are more preferable from the viewpoint of colorability and conductivity. The complex of polyalkylenedioxythiophene and polystyrene sulfonate is obtained, for example, by oxidative polymerization in an aqueous medium using sodium peroxodisulfate as an oxidizing agent in the presence of polystyrene sulfonic acid or a salt thereof and trivalent iron ions. It is obtained as an aqueous dispersion and has the structure of the following formula (1) (see, for example, [Non-Patent Document 1] and [Non-Patent Document 2]).

[Poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) aqueous dispersion]
As a commercial item of the composite of the said polyalkylene dioxythiophene and polystyrene sulfonate, or its compounding product, for example, “SEPLEGYDA” [trade name, manufactured by Shin-Etsu Polymer Co., Ltd.] and “CLEVIOS P” [trade name, H . C. Starck] and the like.
These conductive organic polymer compounds may be used alone or in combination of two or more.
Stephan Kirchmeyer & Knud Reuter, J. Am. Mater. Chem. , 2005, 15, 2077-2088 H. C. Starck brochure, Product Information

If the conductive organic polymer compound itself has good film-forming properties, it is not necessary to use a binder resin, but if it is inferior in film-forming properties, it can be used in combination with a binder resin.
The binder resin is preferably a thermoplastic resin, for example, an aromatic polyester-based or aliphatic polyester-based resin, a polyester urethane-based resin, a polyolefin-based resin such as polyethylene, polypropylene, polymethylpentene, or polycycloolefin, diacetylcellulose, Examples thereof include cellulose resins such as acetylcellulose and acetylcellulose butyrate, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl alcohol resins, polystyrene resins, polycarbonate resins, acrylic resins, polyamide resins, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.
(Formation of conductive organic polymer layer)
In forming the conductive organic polymer layer, first, a conductive organic polymer layer-forming coating solution is prepared.
In a suitable solvent, at least one selected from the above-mentioned conductive organic polymer compounds, preferably polythiophene-based, polyaniline-based and polypyrrole-based compounds, and a binder resin used as necessary, preferably the above-mentioned heat A coating liquid containing various additives such as a plastic resin and an antioxidant, an ultraviolet absorber, and a light stabilizer is prepared, and a conventionally known method such as a bar coating method, a knife coating method, Using a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc., it is applied to a predetermined dry thickness, and dried at about 70 to 130 ° C. for about 30 seconds to 2 minutes. A functional organic polymer layer can be formed.
The refractive index of the conductive organic polymer layer of the (B) layer formed in this way is important to be lower than the refractive index of the optical adjustment layer of the (A) layer for the reasons described above. The thickness is usually about 50 to 500 nm, preferably 180 to 250 nm. The reflectance at a wavelength of 550 nm on the surface is preferably 5% or less, and more preferably 3% or less.
When this reflectance exceeds 5%, reflected light increases, the total light transmittance of a transparent conductive film falls, and transparency worsens.
Furthermore, in the transparent conductive film of this invention, it is preferable that surface resistivity is 300-800 ohms / square and total light transmittance is 86% or more. There is a correlation between the thickness of the conductive organic polymer layer and the surface resistivity, and the surface resistivity tends to decrease as the layer thickness increases. When the surface resistivity is less than 300Ω / □, the total light transmittance is low and the visibility may be deteriorated, so that it is not suitable as a display. If the surface resistivity exceeds 800Ω / □, it is insufficient as an electrode and it is difficult to drive the touch panel. Further, when the total light transmittance is less than 86%, the visibility deteriorates, so that it is unsuitable as a display. A more preferable surface resistivity is 400 to 700 Ω / □, and a more preferable range is 500 to 600 Ω / □. A more preferable total light transmittance is 87% or more, and still more preferably 88% or more.
In addition, the measuring method of said reflectance, total light transmittance, and surface resistivity is explained in full detail later.
[Hard coat layer]
In order to impart scratch resistance to the transparent conductive film of the present invention, a hard coat layer is provided on the back surface of the base film or between the base film and (A) the optical adjustment layer as necessary. be able to. In addition, you may provide a glare-proof function to the hard-coat layer provided in the back surface of a base film.
In order to form this hard coat layer, first, a coating liquid for forming a hard coat layer is prepared.
(Coating fluid for forming hard cord layer)
In the present invention, as the hard coat layer-forming coating liquid having an antiglare function provided on the back surface of the base film, for example, an active energy ray-curable compound and a liquid containing inorganic fine particles or organic fine particles can be used. .
Examples of the active energy ray-curable compound include a radical polymerization type photopolymerizable prepolymer and / or a photopolymerizable monomer. About these, the same thing as what was illustrated in description of the active energy ray hardening compound in the above-mentioned (A) optical adjustment layer can be used.
The inorganic fine particles are preferably silica-based fine particles from the viewpoint of transparency. Examples of the organic fine particles include silicone fine particles, melamine resin fine particles, acrylic resin fine particles, acrylic-styrene copolymer fine particles, polycarbonate fine particles, polyethylene fine particles, polystyrene fine particles, and benzoguanamine resin fine particles. It is done.
In addition, the shape of the inorganic fine particles or organic fine particles is not particularly limited, but spherical, acicular, irregular shapes, and the like are used. From the viewpoint of antiglare performance, an amorphous one is preferable.
Furthermore, the average particle diameter is preferably 6 to 10 μm from the viewpoint of antiglare performance, and the particle size distribution is preferably such that the weight fraction within the range of the average particle diameter ± 2 μm is 70% or more. The average particle size and particle size distribution of the fine particles are values measured by a Coulter counter method.
In the present invention, these inorganic fine particles and organic fine particles may be used singly or in combination of two or more, and the blending amount is the above-mentioned from the viewpoint of antiglare performance. Preferably it is 0.1-30 mass parts with respect to 100 mass parts of active energy ray-curable compounds, More preferably, it is 1-20 mass parts.
The coating liquid for forming a hard coat layer used in the present invention may be prepared by adding the above-described active energy ray-curable compound, inorganic fine particles and organic fine particles, and a photopolymerization initiator used as required, in various solvents as necessary. An additive component such as an antioxidant, an ultraviolet absorber, a silane coupling agent, a light stabilizer, a leveling agent, an antifoaming agent, and the like can be added and dissolved or dispersed at a predetermined ratio. .
Examples of the solvent used here include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, and butanol. And ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and ether solvents such as ethyl cellosolve and propylene glycol monomethyl ether.
The concentration and viscosity of the hard coat layer forming coating solution thus prepared are not particularly limited as long as they can be coated, and can be appropriately selected according to the situation.
The hard coat layer forming coating solution thus prepared is applied to the back surface of the base film by a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, or a gravure. A hard coat layer having an antiglare function is formed by coating using a coating method or the like to form a coating film, drying, and irradiating the coating with an active energy ray to cure the coating film.
Examples of the active energy rays include ultraviolet rays and electron beams. The ultraviolet rays are obtained with a high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, a xenon lamp or the like, and the irradiation amount is usually 100 to 500 mJ / cm ² , while the electron beam is obtained with an electron beam accelerator or the like. The amount is usually 150 to 350 kV. Among these active energy rays, ultraviolet rays are particularly preferable. In addition, when using an electron beam, a cured film can be obtained, without adding a photoinitiator.
In the present invention, the thickness of the hard coat layer thus formed is preferably larger than the average particle diameter of the organic fine particles used. Therefore, the lower limit is about 2 μm, and the upper limit is that of the hard coat layer. From the viewpoint of preventing the hard coat film from curling due to curing shrinkage, it is about 20 μm. A preferable thickness is in the range of 5 to 15 μm, and a particularly preferable thickness is 8 to 12 μm.
When the antiglare property is further required for the transparent conductive film of the present invention, the 60 ° specular gloss measured in accordance with JIS K 5600 is preferably 100 or less, and more preferably 80 or less. If it exceeds 100, the antiglare effect is not sufficiently exhibited.
On the other hand, when a hard coat layer is provided between the base film and the optical adjustment layer (A), for example, silica fine particles and organic fine particles are extracted from the hard coat layer forming coating liquid having the antiglare function described above. A coating solution was prepared, and the coating solution was coated on the base film in the same manner as described above to form a coating film. After drying, the coating film was irradiated with active energy rays, Is hardened to form a hard coat layer. Next, an optical adjustment layer (A) may be formed on the hard coat layer in the same manner as described above.
In the transparent conductive film of the present invention, an antifouling coat layer can be provided on the hard coat layer provided on the back surface of the base film, if necessary. This antifouling coating layer is generally obtained by applying a coating solution containing a fluororesin using a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, or a gravure coating method. It can be formed by coating on the hard coat layer, forming a coating film, and drying treatment.
The thickness of the antifouling coating layer is usually in the range of 1 to 10 nm, preferably 3 to 8 nm.
Next, for examples of different configurations in the transparent conductive film of the present invention, FIG. 1 to FIG. 4 will be described.
FIG. 1 to FIG. 4 is a schematic cross-sectional view showing different examples of the structure of the transparent conductive film of the present invention. 1 shows a transparent conductive film 10 having a configuration in which (A) an optical adjustment layer 2 and (B) a conductive organic polymer layer 3 are sequentially laminated on a base film 1, FIG. 2 corresponds to FIG. 1, the transparent conductive film 20 of the structure by which the hard-coat layer 4-a was further laminated | stacked on the back surface of the base film 1 is shown.
FIG. 3 corresponds to FIG. 1 shows a transparent conductive film 30 having a configuration in which a hard coat layer 4-b is further provided between the base film 1 and the (A) optical adjustment layer 2, and FIG. 4 corresponds to FIG. 1, the transparent conductive film 40 of the structure by which the hard-coat layer 4-a and 4-b were further provided between the back surface of the base film 1, and the base film 1 and the (A) optical adjustment layer 2, respectively. Indicates.
Such a transparent conductive film of the present invention has electrical characteristics and transmittance equivalent to those of ITO without using tin-doped indium oxide (ITO) using indium which is an expensive rare metal, and is transparent for display. It is preferably used as an electrode, particularly as an electrode for a touch panel.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various characteristics in each example were measured according to the following methods.
(1) Surface resistivity of transparent conductive film A test piece was prepared in accordance with JIS K 7194, and the surface resistivity meter “Lorester EP (four-probe probe)” manufactured by Mitsubishi Chemical Corporation was used. The test piece was placed so that the polymer layer surface became the measurement surface, and the surface resistivity was measured.
(2) Total light transmittance of transparent conductive film It measured based on JISK7361-1 using the Nippon Denshoku Industries Co., Ltd. make and haze meter "NDH2000".
(3) Reflectivity of transparent conductive film Using a UV-visible spectrophotometer “UV-3101PC” manufactured by Shimadzu Corporation, the test piece was placed on a black acrylic plate so that the conductive organic polymer layer surface was on the incident light side. After fixing, the reflectance at a wavelength of 550 nm was measured.
(4) Refractive index of (A) layer and (B) layer It measured using the film metrics Co., Ltd. product and thin film measuring apparatus "F20."
(5) 60 ° specular gloss of transparent conductive film Use a gloss meter “VG2000” manufactured by Nippon Denshoku Industries Co., Ltd., and place the test piece so that the opposite surface of the conductive organic polymer layer is on the incident light side. It was measured according to JIS K 5600.
(6) Average particle diameter of metal oxide particles It was measured by a dynamic scattering method.
Example 1
(1) (A) Formation of optical adjustment layer 100 parts by mass of polyester resin [Toyobo Co., Ltd., “Vironal MD1245”, solid content concentration 30% by mass, water dilution] and titanium oxide aqueous dispersion [Taika Co., Ltd. "ND146", average particle size 10 nm, solid content concentration 25% by mass] 240 parts by mass and purified water 566 parts by mass are uniformly mixed to form an optical adjustment layer having a solid content concentration of 1.5% by mass. A coating solution was prepared.
Next, the film was coated on the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Meyer bar, and then dried at 100 ° C. for 1 minute to form an optical adjustment layer having a thickness of 200 nm. did.
(2) (B) Formation of conductive organic polymer layer 100 parts by mass of polythiophene coat [manufactured by Shin-Etsu Polymer Co., Ltd., “SEPLEGYDA”, solid concentration 2.4 mass%] formed in (1) above A transparent conductive film was obtained by coating the surface of the adjustment layer using a Meyer bar and then drying at 130 ° C. for 1 minute to form a conductive organic polymer layer having a thickness of 200 nm. The measurement results of various characteristics are shown in Table 1.
Example 2
(1) (A) Formation of optical adjustment layer 100 parts by mass of polyester resin [Toyobo Co., Ltd., “Byron 20SS”, solid content 30% by mass, diluted toluene / methyl ethyl ketone], antimony-doped tin oxide toluene dispersion [ “SNS-10T” manufactured by Ishihara Sangyo Co., Ltd., average particle size 90 nm, solid content 30% by mass] 200 parts by mass and toluene 270 parts by mass are uniformly mixed to obtain an optical adjustment layer having a solid content concentration of 3% by mass. A forming coating solution was prepared.
Next, the film was coated on the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Meyer bar, and then dried at 100 ° C. for 1 minute to form an optical adjustment layer having a thickness of 200 nm. did.
(2) (B) Formation of conductive organic polymer layer In the same manner as in Example 1 (2), the conductive organic polymer layer is formed on the surface of the optical adjustment layer formed in (1) above, thereby forming a transparent A conductive film was obtained. The measurement results of various characteristics are shown in Table 1.
Example 3
(1) (A) Formation of optical adjustment layer 100 parts by mass of an ultraviolet curable coating agent [manufactured by Dainichi Seika Kogyo Co., Ltd., “Seika Beam EXF-01L (NS)”, solid content 100%], and antimony-doped tin oxide Toluene dispersion “SNS-10T” (supra) 400 parts by mass and 450 parts by mass of toluene were uniformly mixed to prepare a coating solution for forming an optical adjustment layer having a solid content concentration of 3% by mass.
Next, the film was coated on the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Meyer bar, dried at 80 ° C. for 1 minute, and then 500 mJ / cm ² with a high-pressure mercury lamp. An optical adjustment layer having a thickness of 200 nm was formed by irradiation with ultraviolet rays.
(2) (B) Formation of conductive organic polymer layer In the same manner as in Example 1 (2), the conductive organic polymer layer is formed on the surface of the optical adjustment layer formed in (1) above, thereby forming a transparent A conductive film was obtained. The measurement results of various characteristics are shown in Table 1.
Example 4
On the back surface of the base PET film of the transparent conductive film obtained in Example 1, an ultraviolet curable hard coat agent [manufactured by Dainichi Seika Kogyo Co., Ltd., “Seika Beam EXF-01L (NS)”, solid content: 100% After applying a hard coat agent with a solid content concentration of 50% by mass obtained by uniformly mixing 100 parts by mass and 100 parts by mass of toluene with a Meyer bar, drying at 80 ° C. for 1 minute, a high pressure mercury lamp Was irradiated with ultraviolet rays of 250 mJ / cm ² to obtain a transparent conductive film having a hard coat layer having a thickness of 5 μm. The measurement results of various characteristics are shown in Table 1.
Example 5
(1) Formation of an antiglare hard coat layer 100 parts by mass of an ultraviolet curable hard coat agent [manufactured by Dainichi Seika Kogyo Co., Ltd., “SEICA BEAM EXF-01L (NS)”, solid content 100%], and amorphous silicone 5 parts by mass of beads [Mothive Performance Materials Japan GK, “Tospearl 240”], 75 parts by mass of ethyl cellosolve, and 75 parts by mass of isobutanol were mixed uniformly, and the solid content concentration was 40% by mass. An antiglare hard coat agent was prepared. The hard coat agent was applied to the back surface of the base PET film of the transparent conductive film obtained in Example 1 with a Meyer bar, dried at 80 ° C. for 1 minute, and then 250 mJ / cm ² with a high-pressure mercury lamp. The transparent conductive film which has a 4 micrometer-thick anti-glare hard-coat layer was irradiated. The measurement results of various characteristics are shown in Table 1.
Example 6
(1) Formation of a clear hard coat layer 100 parts by mass of an ultraviolet curable hard coat agent [manufactured by Dainichi Seika Kogyo Co., Ltd., “Seika Beam EXF-01L (NS)”, solid content 100%], and 100 parts by mass of toluene Were mixed uniformly to prepare a hard coating agent having a solid concentration of 50% by mass.
Next, after coating with a Meyer bar on the surface of a 188 μm thick polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”], drying at 80 ° C. for 1 minute, and 250 mJ / cm ² with a high pressure mercury lamp. A 5 μm thick hard coat layer was formed by irradiation with ultraviolet rays.
(2) (A) Formation of optical adjustment layer In the same manner as in Example 1, an optical adjustment layer was formed on the surface of the hard coat layer formed in (1) above.
(3) (B) Formation of conductive organic polymer layer A conductive organic polymer layer was formed on the surface of the optical adjustment layer obtained in (2) in the same manner as in Example 1 (2).
(4) Formation of clear hard coat layer A transparent conductive film having a hard coat layer provided on both sides of the base film by forming a hard coat layer on the back surface of the base PET film in the same manner as in (1) above. A film was obtained. The evaluation results of various properties are shown in Table 1.
Comparative Example 1
100 parts by weight of “polythiophene coat” (supra) was applied to the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Mayer bar, and then dried at 130 ° C. for 1 minute. Thus, a transparent conductive film was obtained by forming a conductive organic polymer layer having a thickness of 200 nm. The measurement results of various characteristics are shown in Table 1.
Comparative Example 2
(1) Formation of polyester resin layer 100 parts by mass of polyester resin [Toyobo Co., Ltd., “Byron 20SS”, solid content 30% by mass, diluted toluene / methyl ethyl ketone], 720 parts by mass of toluene, and 180 parts by mass of methyl ethyl ketone Were uniformly mixed to prepare a polyester resin layer forming coating solution having a solid content concentration of 3% by mass.
Next, the coating liquid was applied on the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Mayer bar, and then dried at 100 ° C. for 1 minute to a thickness of 200 nm. A polyester resin layer was formed.
(2) Formation of conductive organic polymer layer 100 parts by mass of “polythiophene coat” (supra) is laminated on the surface of the polyester resin layer formed in the above (1) using a Mayer bar, and then 1 at 130 ° C. A transparent conductive film was obtained by drying for a minute and forming a conductive organic polymer layer having a thickness of 200 nm. The measurement results of various characteristics are shown in Table 1.
Reference example 1
(1) Formation of optical adjustment layer Polyester resin [Toyobo Co., Ltd., “Byron 20SS”, solid content 30% by mass. Toluene / methyl ethyl ketone dilution] 100 parts by mass, antimony-doped tin oxide toluene dispersion [manufactured by Ishihara Sangyo Co., Ltd., “SNS-10T”, average particle size 90 nm, solid content 30% by mass] 900 parts by mass, toluene 9000 parts by mass The parts were uniformly mixed to prepare an optical adjustment layer forming coating solution having a solid content concentration of 3% by mass.
Next, the coating liquid was applied on the surface of a polyethylene terephthalate film [Toyobo Co., Ltd., “A4300”] having a thickness of 188 μm with a Mayer bar, and then dried at 100 ° C. for 1 minute to a thickness of 200 nm. The optical adjustment layer was formed.
(2) (B) Formation of conductive organic polymer layer In the same manner as in Example 1 (2), the conductive organic polymer layer is formed on the surface of the optical adjustment layer formed in (1) above, thereby forming a transparent An attempt was made to produce a conductive film, but when the conductive organic polymer layer was laminated, the metal oxide in the optical adjustment layer was often removed, making it difficult to form a conductive organic polymer layer having a good surface state. . The refractive index of the optical adjustment layer formed in (1) was 1.78.

  The transparent conductive film of the present invention has the same electrical properties and transmittance as the ITO without using tin-doped indium oxide (ITO) using indium which is an expensive rare metal, such as a transparent electrode for display, In particular, it is suitably used as a touch panel electrode.

Claims (7)

A transparent conductive film in which a layer (A) and a layer (B) are sequentially laminated on a base film, wherein the layer (A) is a binder resin of a thermoplastic resin and / or an active energy ray curable resin. And an optical adjustment layer comprising metal oxide particles having an average particle size of 200 nm or less, the metal oxide particles comprising titanium oxide particles and / or antimony-doped tin oxide particles , and the layer (B), It is a conductive organic polymer layer, the refractive index of the (A) optical adjustment layer is 1.65 to 1.90, the surface resistivity is 300 to 800Ω / □, and the total light transmittance is 86% or more. A transparent conductive film, characterized in that (B) in the conductive organic polymer layer surface, the reflectance of the wavelength of 550nm is 5% or less, the transparent conductive film according to claim 1. (B) The transparent conductive film of Claim 1 or 2 whose refractive index of a conductive organic polymer layer is lower than the refractive index of (A) optical adjustment layer. (B) The electroconductive organic polymer compound which comprises an electroconductive organic polymer layer is at least 1 sort (s) chosen from polythiophene type, polyaniline type, and a polypyrrole type compound in any one of Claims 1-3. Transparent conductive film. (A) The optical adjustment layer contains titanium oxide particles and / or antimony-doped tin oxide particles having an average particle size of 200 nm or less with respect to 100 parts by mass of the binder resin of thermoplastic resin and / or active energy ray-curable resin. The transparent conductive film in any one of Claims 1-4 included in the ratio of 700 mass parts. The transparent conductive film in any one of Claims 1-5 by which a hard-coat layer is provided in the back surface of a base film. A substrate film, (A) between the optical adjustment layer, a hard coat layer is provided, the transparent conductive film according to any one of claims 1-6.

Images