JP2012218368A - Transparent conductive laminated film and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive laminated film capable of improving visibility of a display device including a patterned transparent conductive layer (transparent electrode) such as a capacitance type touch panel.SOLUTION: In this transparent conductive laminated film, a hard coat layer formed of a hardened material of a polymerizable composition containing nanometer-size inorganic particles and a vinyl-based compound is laminated at least on one surface of a base material film formed of a transparent material, and a transparent conductive layer is formed in a partial region on a surface of the hard coat layer. The vinyl-based compound contains silicon-free multifunctional (meta) acrylate and silicon-containing multifunctional (meta) acrylate. The obtained transparent conductive laminate film can be used for a transparent electrode substrate of a projection type capacitance type touch panel and the like. The average primary particle size of the inorganic particles is around 1-100 nm. The inorganic particle may be a metal oxide particle.

Description

  The present invention relates to a transparent conductive laminated film used for an electrode of a projected capacitive touch panel and a capacitive touch panel provided with the laminated film.

  In recent years, with the advancement of electronic displays as man-machine interfaces, interactive input systems have become widespread. Among them, devices that integrate a touch panel (coordinate input device) with a display are ATMs (automated teller machines), merchandise management, Widely used in outworkers (diplomatic, sales), information display, entertainment equipment. Lightweight and thin displays such as liquid crystal displays can be made keyboard-less, and their features are alive, so the number of cases where touch panels are used in mobile devices is increasing. The touch panel can be classified into an optical method, an ultrasonic method, a capacitance method, a resistance film method, and the like according to a position detection method. Among these methods, the electrostatic capacitance method is a method for detecting a position by using a change in electrostatic capacitance. However, in recent years, the electrostatic capacitance method adopts an ITO grid method because of its excellent functionality. Capacitive touch panels are in the spotlight as they are used in mobile devices such as smartphones and electronic paper. In the ITO grid method, a patterned ITO (indium oxide-tin oxide composite oxide) film is formed on a transparent substrate, but the refractive index of the ITO film is higher than that of the transparent substrate. Therefore, there is a difference in light transmittance between the region where the ITO film is formed and the region where the ITO film is not formed. However, since the ITO film is also transparent, the conventional touch panel image has no effect on the visibility. However, since the image of the touch panel in recent years has been displayed precisely, the reflection of the pattern by the ITO film affects the visibility. For this reason, as a method to prevent the ITO film deposition pattern from being seen as much as possible, niobium dioxide having a refractive index close to that of ITO is deposited on the entire surface (deposition without patterning), and then the ITO film is pattern deposited on the necessary part. (Etching method) is also used. In this case, in order to maintain the adhesion strength of the ITO film, a silicon oxide film is further formed by vapor deposition on the vapor deposition layer of niobium dioxide, and then the ITO film is vapor deposited, and the process is complicated. Met.

  On the other hand, as a method for controlling the refractive index of a transparent plastic, a method in which metal fine particles having a refractive index higher than that of a plastic is contained in a nano size is known. For example, Japanese Patent Laid-Open No. 61-291650 (Patent Document 1). Discloses a high refractive index resin composition in which one or more inorganic fine particle mixtures containing inorganic fine particles having a particle size of 200 mm or less and a refractive index of 1.6 or more are dispersed in a synthetic resin. JP 2000-327836 A (Patent Document 2) discloses a high refractive index metal ultrafine particle dispersion in which metal ultrafine particles having a particle diameter of 0.001 to 0.1 μm are dispersed in a polymer as a dispersion medium. A polymer is disclosed. These documents include transparent glasses such as polymethyl methacrylate and styrene resin, nanometer-sized titania and silver for the purpose of improving the refractive index while maintaining lightness in lenses for glasses and optical instruments. It is described that the refractive index of a transparent resin is increased by containing metal fine particles.

  Furthermore, Japanese Patent Application Laid-Open No. 2008-52088 (Patent Document 3) discloses an antireflection film for a display in which an easy-adhesive layer having antistatic properties, a hard coat layer, and a low refractive index layer are formed on a transparent film. Has been. This document describes that the hard coat layer contains fine oxide particles such as zirconia, titania, selenium oxide, and zinc oxide in order to improve the antireflection performance. In the examples, zirconia having an average particle size of 80 nm is described. It is blended.

  However, these documents do not describe the transparent conductive layer, and do not describe the technical significance of the optical characteristics in the laminate of the patterned transparent conductive layer and the transparent substrate. In addition, when using films containing fine metal particles for optical applications, increasing the proportion of fine metal particles generally decreases the total light transmittance and improves haze even for nanometer-sized particles. To do. That is, in a transparent film containing metal fine particles, there is a trade-off relationship between transparency and refractive index, so it is difficult to increase the refractive index using metal fine particles and achieve both optical properties such as transparency. It was. Therefore, in the capacitive touch panel in which the transparent electrode is patterned, it is necessary to suppress the reflection while satisfying such a trade-off relationship, and it is particularly difficult to improve the visibility.

  International Publication WO2010 / 114056 (Patent Document 4) discloses a cured resin on at least one surface of a transparent organic polymer substrate in order to suppress the reflection (bone appearance) of a capacitive touch panel pattern. In a transparent conductive laminate in which layers and further transparent conductive layers are sequentially laminated, a laminate in which a cured resin layer contains a resin component and ultrafine particles having an average primary particle diameter of 1 nm or more is disclosed. In the example of this document, a cured resin layer containing 72 or 82 parts by weight of titanium oxide having an average particle diameter of 30 nm is formed on a transparent substrate formed of PET or PC with respect to 100 parts by weight of urethane acrylate, A laminate having an ITO film formed on a cured resin layer is manufactured.

  However, even in this laminate, it is difficult to suppress light scattering, and it is difficult to achieve both reflection of a pattern and optical properties such as high transparency. Furthermore, the proportion of fine particles was small, and the effect of improving the refractive index was low.

Japanese Patent Application Laid-Open No. 61-291650 (Claim 1, column of effects of conventional technology and invention, examples) Japanese Unexamined Patent Publication No. 2000-327836 (Claim 1, column of effects of conventional technology and invention, examples) JP 2008-52088 A (claims, paragraphs [0026] to [0028], examples) International Publication No. WO2010 / 114056 (Claims, Examples)

  Accordingly, an object of the present invention is to provide a transparent conductive laminated film capable of improving the visibility of a display device having a patterned transparent conductive layer (transparent electrode) while suppressing light scattering and maintaining high transparency, and It is providing the electrostatic capacitance type touch panel provided with this film.

  Another object of the present invention is to provide a transparent conductive laminated film capable of suppressing reflection of a patterned transparent conductive layer of a capacitive touch panel and a capacitive touch panel provided with this film.

  Still another object of the present invention is to provide a transparent conductive laminated film capable of improving the visibility of a capacitive touch panel and a capacitive touch panel provided with this film.

  Another object of the present invention is to easily manufacture a capacitive touch panel with improved visibility.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor cured a polymerizable composition containing nanometer-sized inorganic particles and a vinyl compound on at least one surface of a base film formed of a transparent material. The visibility of a display device having a patterned transparent conductive layer (transparent electrode) is improved by laminating a hard coat layer formed of an object and forming a transparent conductive layer on a part of the hard coat layer. The present invention has been completed by finding out what can be done.

  That is, the transparent conductive laminated film of the present invention is a polymerization comprising a base film formed of a transparent material, and laminated on at least one surface of the base film and containing nanometer-sized inorganic particles and a vinyl compound. A transparent conductive laminated film comprising a hard coat layer formed of a cured product of the adhesive composition and a transparent conductive layer formed in a partial region of the surface of the hard coat layer, wherein the vinyl compound is Silicon-free polyfunctional (meth) acrylate and silicon-containing polyfunctional (meth) acrylate are included. The silicon-free polyfunctional (meth) acrylate is a combination of 5 to 7 functional (meth) acrylate and 2 to 4 functional (meth) acrylate, and the silicon-containing polyfunctional (meth) acrylate is silicone (meta). ) Acrylate may be used. The ratio of the 5-7 functional (meth) acrylate and the 2-4 functional (meth) acrylate is the former / the latter = 99/1 to 30/70, and the silicon-containing polyfunctional (meth) acrylate. The ratio may be about 0.1 to 30 parts by weight with respect to 100 parts by weight of the silicon-free (meth) acrylate. The polymerizable composition may further contain a cellulose ester. The ratio (weight ratio) between the vinyl compound and the inorganic particles may be about the former / the latter = 50/50 to 10/90. The inorganic particles may be metal oxide particles having an average primary particle size of 1 to 100 nm. The inorganic particles may contain titanium and / or zirconium. The refractive index difference between the base film and the transparent conductive layer may be 0.3 or more. The refractive index of the hard coat layer may be larger than the refractive index of the base film and smaller than the refractive index of the transparent conductive layer. In the transparent conductive laminated film of the present invention, the difference in total light transmittance between the region where the transparent conductive layer is formed and the region where the transparent conductive layer is not formed may be 2%. The total light transmittance of the region where the transparent conductive layer is not formed may be 80% or more, and the haze of the region where the transparent conductive layer is not formed may be 5% or less. On the surface of the hard coat layer, the area ratio between the region where the transparent conductive layer is formed and the region where the transparent conductive layer is not formed may be about the former / the latter = 9/1 to 1/9. The base film may be formed of a polyester resin or a cellulose ester. The transparent conductive laminated film having the transparent conductive layer may be a transparent electrode substrate of a touch panel formed by patterning the transparent conductive layer, and the transparent electrode substrate may be a viewing-side upper electrode substrate.

  In the present invention, the transparent conductive layer is formed by forming a hard coat layer on at least one surface of a base film by coating, and then forming a transparent conductive layer on the obtained hard coat layer by a physical or chemical vapor phase method. A method for producing a laminated film is also included. The present invention also includes a projected capacitive touch panel that includes the transparent conductive laminated film as an electrode substrate.

  In the present invention, a hard coat layer formed of a cured product of a polymerizable composition containing nanometer-sized inorganic particles and a specific vinyl compound is laminated on at least one surface of a base film formed of a transparent material. Furthermore, since a transparent conductive layer is formed in a part of the surface of the hard coat layer, a patterned transparent conductive layer (transparent electrode) while suppressing light scattering and maintaining high transparency The visibility of the display device having the above can be improved. In particular, reflection of a patterned transparent conductive layer such as a projected capacitive touch panel can be suppressed. Furthermore, in the present invention, such a capacitive touch panel with improved visibility can be easily manufactured.

[Transparent conductive laminated film]
The transparent conductive laminated film of the present invention is a polymerizable composition comprising a base film formed of a transparent material, laminated on at least one surface of the base film, and comprising nanometer-sized inorganic particles and a vinyl compound. A hard coat layer formed of a cured product of the product, and a transparent conductive layer formed in a partial region of the surface of the hard coat layer.

(Base film)
The base film may be a polymer film that can be formed by vapor deposition of a transparent conductive layer such as ITO formed of a transparent material. For example, a cellulose derivative, a polyester resin, a polyamide resin, a polycarbonate resin, ) Acrylic resin may be used. Of these, cellulose esters, polyester resins and the like are widely used.

Examples of the cellulose ester include cellulose acetate such as cellulose triacetate (TAC), cellulose acetate C _3-4 acylate such as cellulose acetate propionate, and cellulose acetate butyrate. Polyester resins include polyalkylene arylate resins such as PET and PEN.

Of these, poly _C2-4 alkylene arylates such as PET are particularly preferred. Furthermore, the base film may be a film obtained by biaxially stretching a polyalkylene arylate resin such as PET or PEN.

  The base film contains additives such as stabilizers (antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, etc.), crystal nucleating agents, plasticizers, antistatic agents, etc., as necessary. May be. These additives can be used alone or in combination of two or more.

  The thickness of a base film is about 10-300 micrometers according to a use.

(Hard coat layer)
The hard coat layer is formed of a cured product of a polymerizable composition containing nanometer-sized inorganic particles and a vinyl compound. In the present invention, by including nanometer-sized inorganic particles, visibility can be improved only by interposing a single hard coat layer.

(A) Inorganic particles The particle size of the inorganic particles may be nanometer size. Specifically, the average primary particle size can be selected from the range of about 1 to 100 nm, for example, 2 to 50 nm, preferably 3 to 40 nm, Preferably it is about 5-30 nm (especially 8-20 nm). If the particle size of the inorganic particles is too large, light scattering increases and transparency decreases.

  The shape of the inorganic particles is not particularly limited, and may be spherical, ellipsoidal, polygonal (polygonal, tetrahedral, cuboid, etc.), plate, rod, indefinite, etc. Isotropic shapes such as a substantially spherical shape are preferred from the viewpoint of improving the visibility.

  The inorganic particles should just have a refractive index larger than the refractive index of a base film, for example, is about 1.7-2.0. If the refractive index is too low, the effect of increasing the refractive index of the hard coat layer is low, and if it is too high, light scattering increases and transparency decreases.

  As the inorganic compound constituting the inorganic particles, for example, a metal oxide, a metal oxide, and a metal oxide are preferable from the viewpoint of an effect of increasing the refractive index.

  Examples of the metal oxide include Group 4A metal oxides (eg, titanium oxide, zirconium oxide, etc.), Group 5A metal oxides (eg, vanadium oxide), and Group 6A metal oxides (molybdenum oxide, oxide). Tungsten), Group 7A metal oxides (manganese oxide, etc.), Group 8 metal oxides (nickel oxide, iron oxide, etc.), Group 1B metal oxides (copper oxide, etc.), Group 2B metal oxides ( Zinc oxide, etc.), Group 3B metal oxides (aluminum oxide, indium oxide, etc.), Group 4B metal oxides (silicon oxide, tin oxide, etc.), Group 5B metal oxides (antimony oxide, etc.) and the like. . These metal oxides can be used alone or in combination of two or more.

  Among these metal oxides, the refractive index of the hard coat layer can be increased in a small proportion, and even if the addition amount is increased, the increase in haze can be suppressed, so that periodic table 4A group such as titanium oxide and zirconium oxide can be used. Metal oxides are preferred, and titanium oxide is particularly preferred.

As titanium oxide, conventional titanium oxide [compositional formula TixOy] can be used, and titanium dioxide, Ti ₂ O ₅ , Ti ₂ O _{3 and the} like can be used, but usually titanium dioxide is the main component. Further, the titanium oxide may be a crystal form such as anatase type, rutile type, brookite type, etc., but rutile type titanium dioxide is preferred.

  Inorganic particles (particularly titanium oxide) are preferably particles that are not surface-treated from the viewpoint of suppressing aggregation. The dispersion state of the inorganic particles can be evaluated by the total light transmittance and haze of the hard coat layer. Even if the total light transmittance of the hard coat layer is 75% or more, preferably 80% or more, more preferably 85% or more. The haze may be 5% or less, preferably 3% or less (for example, 0.01 to 3%), more preferably 2% or less (for example, 0.1 to 2%).

(B) Vinyl compound The vinyl compound contains a silicon-free polyfunctional (meth) acrylate and a silicon-containing polyfunctional (meth) acrylate.

(B1) Silicon-free polyfunctional (meth) acrylate As silicon-free polyfunctional (meth) acrylate, (meth) acrylate having 2 or more (for example, about 2 to 8) (meth) acryloyl groups in the molecule is used. used.

Examples of the bifunctional (meth) acrylate include allyl (meth) acrylate; alkanediol di (meth) acrylate such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and 1,4-butanediol di (meth) acrylate. Alkane polyol di (meth) acrylate such as glycerin di (meth) acrylate; polyalkylene glycol di (meth) acrylate such as diethylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate; 2,2-bis Di (meth) acrylates of C _2-4 alkylene oxide adducts of bisphenols (bisphenol A, bisphenol S, etc.) such as (4- (meth) acryloxyethoxyphenyl) propane; Examples thereof include bridged cyclic di (meth) acrylates such as chlorodecane dimethanol di (meth) acrylate and adamantane di (meth) acrylate. Further, examples of the bifunctional vinyl compound include oligomers or resins such as epoxy di (meth) acrylate, polyester di (meth) acrylate, and (poly) urethane di (meth) acrylate.

Examples of trifunctional or higher (about 3 to 8 functional) (meth) acrylates include, for example, esterified products of polyhydric alcohol and (meth) acrylic acid, such as glycerin tri (meth) acrylate, trimethylolpropane tri (meth). Acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate; ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate; dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa ( And (meth) acrylate. Further, in these polyfunctional (meth) acrylates, the polyhydric alcohol may be an adduct of alkylene oxide (for example, C _2-4 alkylene oxide such as ethylene oxide or propylene oxide). The average addition mole number of alkylene oxide can be selected from the range of about 0-30 mol (especially 1-10 mol), for example. These polyfunctional (meth) acrylates can be used alone or in combination of two or more.

  Among these polyfunctional (meth) acrylates, trifunctional or higher functional (meth) acrylates (particularly, 4-8 functional (meth) acrylates such as dipentaerythritol hexa (meth) acrylate) are selected from the viewpoint of hard coat properties and the like. The polyfunctional (meth) acrylate containing at least is preferable. In particular, 5 to 7 functional (meth) acrylates and 2 to 4 functional (meth) acrylates [particularly 3 to 4 functional (meth) acrylates such as pentaerythritol tri (meth) acrylate] may be combined. The ratio (weight ratio) is, for example, the former / the latter = 100/0 to 10/90, preferably 99/1 to 30/70, more preferably 90/10 to 50/50 (particularly 80/20 to 40/60). ) In the present invention, by combining polyfunctional (meth) acrylates having different numbers of functional groups in such a ratio, the mechanical properties of the hard coat layer can be improved, a large amount of inorganic particles can be blended, and the refractive index of the hard coat layer can be improved. The rate can be improved.

(B2) Silicon-containing polyfunctional (meth) acrylate Silicone (meth) acrylate is widely used as the silicon-containing polyfunctional (meth) acrylate. In the present invention, in addition to the silicon-free polyfunctional (meth) acrylate, by adding a silicon-containing polyfunctional (meth) acrylate, it is possible to suppress haze despite containing a large amount of inorganic particles, and transparent In addition to improving the optical characteristics such as the property, the refractive index can be adjusted and the visibility can be improved.

Silicone (meth) acrylate usually has an organosiloxane unit [—Si (—R) ₂ —O—] (the group R represents a substituent), and the number of Si atoms (or organosiloxane units) is One or more (for example, about 1 to 30, preferably about 1 to 20, more preferably about 1 to 15) may be included in one molecule. Moreover, the number of (meth) acryloyl groups may be 2 or more (for example, 2 to 20, preferably 2 to 15, more preferably about 2 to 10) in one molecule.

The silicone (meth) acrylate may be a monomer, an oligomer (or prepolymer), or a combination of monomers and oligomers. The oligomer (prepolymer) may be a polysiloxane oligomer having a plurality of (—Si—O) bonds, and may be a hydrolytic condensable group (for example, a C _1-4 alkoxy group such as methoxy or ethoxy, It may be a multimer such as a dimer or trimer by hydrolytic condensation of a silicone (meth) acrylate monomer having a halogen atom such as a chlorine atom.

  Typical silicone (meth) acrylates include silicone mono to tetra (meth) acrylate having one Si atom in one molecule, silicone tetra to hexa (meth) acrylate having two Si atoms in one molecule, and the like. It can be illustrated.

  Among these silicone (meth) acrylates, a plurality of (for example, 2 to 10, preferably 3 to 8, more preferably about 4 to 7) (meth) acryloyl groups and one or more in one molecule. Silicone (meth) acrylate component having a Si atom (for example, 1 to 20, preferably 1 to 10, more preferably about 1 to 6) [for example, silicone di to hexa (meth) acrylate, preferably silicone Tri to hexa (meth) acrylate] is preferable. Silicone di (meth) acrylate is available under the trade name “EBECRYL350” (manufactured by Daicel Cytec Co., Ltd.). Silicone hexa (meth) acrylate is trade name “EBECRYL1360” (manufactured by Daicel Cytech Co., Ltd.). ) Etc.

  The proportion of the silicon-containing polyfunctional (meth) acrylate is, for example, 0.1 to 30 parts by weight, preferably 0.2 to 20 parts by weight, more preferably 100 parts by weight of the silicon-free polyfunctional (meth) acrylate. Is about 0.5 to 10 parts by weight (particularly 1 to 5 parts by weight).

  As vinyl compounds, in addition to polyfunctional (meth) acrylates, monofunctional vinyl compounds, for example, (meth) acrylic acid esters such as alkyl (meth) acrylate, cycloalkyl (meth) such as cyclohexyl (meth) acrylate, etc. Vinyl monomers such as acrylate, aryl (meth) acrylate such as phenyl (meth) acrylate, vinyl pyrrolidone, etc. having a bridged cyclic hydrocarbon group such as isobornyl (meth) acrylate and adamantyl (meth) acrylate Etc. may be included.

  The ratio (weight ratio) between the vinyl compound and the inorganic particles can be appropriately selected according to the difference in refractive index between the base film and the transparent conductive layer, and can be selected, for example, from a range of about 99/1 to 1/99. For example, the former / the latter = 80/20 to 5/95, preferably 50/50 to 10/90, more preferably about 40/60 to 15/85 (particularly 30/70 to 20/80). In the present invention, since a specific vinyl compound is combined, even if a large amount of inorganic particles are blended, the mechanical properties are excellent and the refractive index of the hard coat layer can be improved. If the proportion of the inorganic particles is too small, the refractive index cannot be improved, and if it is too large, the mechanical properties of the hard coat layer are lowered.

(C) Polymerizable composition The polymerizable composition (curable resin precursor) may contain a cellulose ester in order to improve the coatability and mechanical properties of the hard coat layer. Examples of the cellulose ester include cellulose C _2-6 acylates such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate. These cellulose esters can be used alone or in combination of two or more.

Among these cellulose esters, the solubility in a solvent is high, the preparation of the coating liquid is easy, the viscosity of the coating liquid can be easily adjusted by adding a small amount, and the fine particles in the coating liquid can be easily adjusted. Cellulose C _2-4 acylates such as cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate (especially cellulose acetate such as cellulose acetate propionate) from the point that aggregation can be suppressed and storage stability can be improved. C _3-4 acylate) is preferred.

  The ratio of the cellulose ester is, for example, 0.01 to 30 parts by weight, preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight (particularly 0.1. 2 to 1 part by weight).

  The polymerizable composition may contain a polymerization initiator. The polymerization initiator may be a thermal polymerization initiator (thermal radical generator such as a peroxide such as benzoyl peroxide) or a photopolymerization initiator (photo radical generator). A preferred polymerization initiator is a photopolymerization initiator. Examples of the photopolymerization initiator include acetophenones or propiophenones, benzyls, benzoins, benzophenones, thioxanthones, and acylphosphine oxides. The photopolymerization initiator may contain a conventional photosensitizer and a photopolymerization accelerator (for example, tertiary amines). The proportion of the photopolymerization initiator is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight (particularly 1 to 5 parts by weight) with respect to 100 parts by weight of the vinyl compound. ) Degree. The polymerizable composition may further contain a conventional additive as long as the transparency is not impaired. The polymerizable composition preferably further contains a solvent from the viewpoint of coatability.

  The polymerizable composition (curable resin precursor) may be a thermosetting composition, but may be a photocurable compound that can be cured in a short time, for example, an ultraviolet curable compound or an EB curable compound. Good. In particular, a practically advantageous resin precursor is an ultraviolet curable resin.

  The refractive index of the hard coat layer is larger than the refractive index of the base film and smaller than the refractive index of the transparent conductive layer, and can be selected from a range of about 1.5 to 2.2, for example, 1.55. To 2.0, preferably 1.6 to 1.95, more preferably about 1.65 to 1.9 (especially 1.7 to 1.85).

  The thickness of the hard coat layer is, for example, about 0.01 to 30 μm, preferably 0.015 to 20 μm, and more preferably about 0.02 to 10 μm (particularly 0.03 to 10 μm).

(Transparent conductive layer)
The transparent conductive layer can be a conventional transparent conductive layer used as a transparent electrode, and may be a transparent conductive layer formed of a conductive inorganic compound. As the conductive inorganic compound, a metal oxide such as an ITO film is widely used.

  In the present invention, the transparent conductive layer is (partially) formed in a partial region on the surface of the hard coat layer, and is usually formed by being patterned in a lattice shape or the like. In this invention, it can prevent effectively that the pattern by the difference in the light transmittance of a laminated | multilayer film generate | occur | produces with the presence or absence of a transparent conductive layer is reflected.

  The refractive index difference between the base film and the transparent conductive layer may be 0.3 or more, for example, 0.3 to 0.9, preferably 0.35 to 0.8, and more preferably 0.4 to It may be about 0.75 (particularly 0.5 to 0.75).

  The thickness of the transparent conductive layer may be, for example, about 1 to 1000 nm, preferably 5 to 500 nm, more preferably about 10 to 400 nm (particularly 20 to 300 nm).

(Characteristics of transparent conductive laminated film)
The transparent conductive laminated film of the present invention is excellent in transparency, and the total light transmittance in the region where the transparent conductive layer is formed is, for example, 75% or more, preferably 80 to 99%, more preferably 85 to 95. %. On the other hand, the total light transmittance in the region where the transparent conductive layer is not formed is, for example, 80% or more, preferably 85 to 99%, and more preferably about 90 to 95%.

  The difference in total light transmittance between the region where the transparent conductive layer is formed and the region where the transparent conductive layer is not formed may be, for example, 2% or less, preferably 0.1 to 2%, more preferably Is about 0.2 to 1.5%.

  Thus, although the transparent conductive laminated film of this invention is excellent in transparency, it has a refractive index difference with the area | region in which the transparent conductive layer was formed, and the area | region in which the transparent conductive layer was not formed. Therefore, in such a film, visibility such as reflection of a pattern is deteriorated due to a difference in reflectance between regions. However, in the present invention, although there is a difference in refractive index, by interposing a hard coat layer containing nanometer-sized inorganic particles, reflection of a pattern due to the difference in refractive index can be suppressed, and visibility is improved. it can.

  The transparent conductive laminated film of the present invention has a low haze, and the haze in the region where the transparent conductive layer is formed is, for example, 5% or less, preferably 0.1 to 3%, more preferably 0.3 to 1. It is about 5%. On the other hand, the haze in the region where the transparent conductive layer is not formed is, for example, 5% or less, preferably 0.1 to 3%, more preferably about 0.3 to 2%.

  The transparent conductive laminated film of the present invention only needs to have a hard coat layer formed on at least one surface, and may be formed on both surfaces. When the hard coat layer is formed on both sides, the transparent conductive layer may also be formed on both sides.

  The transparent conductive laminated film of the present invention may be further combined with a conventional functional layer such as an anti-Newton ring layer, a light scattering layer, an antireflection layer, or a low refractive index layer.

[Method for producing transparent conductive laminated film]
In the transparent conductive laminated film of the present invention, after forming a hard coat layer on at least one surface of the base film by coating, a transparent conductive layer is formed on the obtained hard coat layer by a physical or chemical vapor phase method. It is obtained by the method to do.

(Hard coat layer forming process)
In detail, in the formation process of a hard-coat layer, after apply | coating the coating liquid containing a polymeric composition, it can obtain by hardening.

  As a coating method of the polymerizable composition, conventional methods such as roll coater, air knife coater, blade coater, rod coater, reverse coater, bar coater, comma coater, dip squeeze coater, die coater, gravure coater, microgravure coater Examples include coater, silk screen coater method, dip method, spray method, spinner method and the like. Of these methods, the bar coater method and the gravure coater method are widely used. If necessary, the coating solution may be applied a plurality of times.

  When the polymerizable composition contains an organic solvent, it may be dried as necessary after coating. Drying may be performed at a temperature of about 50 to 150 ° C., preferably 60 to 140 ° C., and more preferably about 70 to 130 ° C., for example.

  In the curing step, the polymerizable composition may be cured by heating depending on the type of the polymerization initiator, but it can usually be cured by irradiation with active energy rays. As active energy rays, for example, radiation (gamma rays, X-rays, etc.), ultraviolet rays, visible rays, electron beams (EB) and the like can be used, and usually ultraviolet rays and electron beams are often used.

As the light source, for example, in the case of ultraviolet rays, a Deep UV lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a halogen lamp, a laser light source (light source such as a helium-cadmium laser or an excimer laser) may be used. it can. The amount of irradiation light (irradiation energy) varies depending on the thickness of the coating film, but may be, for example, about 50 to 10,000 mJ / cm ² , preferably 70 to 7000 mJ / cm ² , and more preferably about 100 to 5000 mJ / cm ² .

  In the case of an electron beam, a method of irradiating an electron beam with an exposure source such as an electron beam irradiation apparatus can be used. The irradiation amount (dose) varies depending on the thickness of the coating film, but is, for example, about 1 to 200 kGy (gray), preferably 5 to 150 kGy, and more preferably 10 to 100 kGy (particularly 20 to 80 kGy). The acceleration voltage is, for example, about 10 to 1000 kV, preferably about 50 to 500 kV, and more preferably about 100 to 300 kV.

  In addition, you may perform irradiation of an active energy ray in inert gas (for example, nitrogen gas, argon gas, helium gas etc.) atmosphere if necessary.

  In order to improve the adhesion of the transparent conductive layer to the hard coat layer, the hard coat layer may be subjected to a surface treatment. Examples of the surface treatment include conventional surface treatments such as corona discharge treatment, flame treatment, plasma treatment, ozone and ultraviolet irradiation treatment.

(Transparent conductive layer formation process)
The transparent conductive layer formed of a conductive inorganic compound is not particularly limited as long as it is a method capable of forming a thin film containing a metal or a metal compound, and can be formed using a conventional film forming method. Examples of the film formation method include physical vapor deposition (PVD) [for example, vacuum deposition, flash deposition, electron beam deposition, ion beam deposition, ion plating (for example, HCD, electron beam RF). Method, arc discharge method, etc.), sputtering method (eg, DC discharge method, radio frequency (RF) discharge method, magnetron method, etc.), molecular beam epitaxy method, laser ablation method, etc.], chemical vapor phase method (CVD) [eg, , Thermal CVD method, plasma CVD method, MOCVD method (metal organic chemical vapor deposition method), photo CVD method, etc.], ion beam mixing method, ion implantation method and the like. Of these film formation methods, physical vapor deposition methods such as vacuum deposition, ion plating, and sputtering, and chemical vapor deposition are widely used, and sputtering and plasma CVD (particularly sputtering) are preferred. .

  On the other hand, a transparent conductive layer composed of a conductive polymer can be produced by applying and drying a liquid composition containing a conductive polymer with the above-described coating or the like.

  The transparent conductive layer is patterned into a lattice shape or a stripe shape according to the type of the touch panel or the like. In a projected capacitive touch panel, for example, a transparent conductive layer is formed on the entire surface of the hard coat layer, and then patterned into a lattice pattern by etching using acid or alkali, or by patterning using a mask or the like. Examples thereof include a method of forming a lattice pattern.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The transparent electroconductive laminated film obtained by the Example and the comparative example was evaluated by the following items.

[Haze (HZ) and total light transmittance (TT)]
It measured based on JISK7136 using the haze meter (The Nippon Denshoku Co., Ltd. make, brand name "NDH-5000W").

[Visibility]
The region where the transparent conductive layer was formed on the black paper and the region where the transparent conductive layer was not formed were placed side by side, visually observed and judged according to the following criteria.

◎: The difference is not known ○: The difference is difficult to understand △: There is a slight difference ×: There is a clear difference.

[Compounding ingredients of hard coat layer]
6-functional acrylate: 6-functional acrylic UV curing monomer, “DPHA” manufactured by Daicel Cytec Co., Ltd.
Trifunctional acrylate: Trifunctional acrylic UV curing monomer: "PETIA" manufactured by Daicel Cytec Co., Ltd.
Silicone acrylate: Hexafunctional acrylic UV curing monomer, “EBECRYL1360” manufactured by Daicel Cytec Co., Ltd.
CAP: cellulose acetate propionate, “CAP-482-20” manufactured by Eastman, degree of acetylation = 2.5%, degree of propionylation = 46%, polystyrene-equivalent number average molecular weight 75,000
Titanium oxide dispersion: “RTTDNB15WT% -N39” manufactured by CI Kasei Co., Ltd.
BuOH: 1-butanol, boiling point 113 ° C
MMPG: 1-methoxy-2-propanol, boiling point 119 ° C
MEK: Methyl ethyl ketone IPA: 2-propanol Initiator 1: Photopolymerization initiator, “Irgacure 184” manufactured by Ciba Japan Co., Ltd.
Initiator 2: Photopolymerization initiator, “Irgacure 907” manufactured by Ciba Japan Co., Ltd.

Comparative Examples 1-2 and Examples 1-3
The acrylate, cellulose ester, and titanium oxide dispersion shown in Table 1 were dissolved in the mixed solvent shown in Table 1. After casting using this solution on a triacetylcellulose film using a wire bar # 5, it was left in an oven at 60 ° C. for 1 minute, and then the coated film was irradiated with an ultraviolet irradiation device (USHIO INC., High pressure mercury). Lamp, ultraviolet irradiation amount: 800 mJ / cm ² ), an ultraviolet curing treatment was performed, and the coating film was cured to form a hard coat layer. Further, a transparent conductive layer is formed on the hard coat layer by sputtering a composite oxide of InO ₂ and SnO ₂ (ITO), and then the ITO film is removed by immersion in 1N hydrochloric acid to be transparent. A region where a conductive layer was not formed was created. Table 1 shows the results of measuring the haze, total light transmittance, and refractive index of the hard coat layer of the obtained laminated film where the transparent conductive layer is not formed, and evaluating the visibility.

  As is clear from the results in Table 1, the laminated film of Comparative Example 1 has a low refractive index and low visibility. Moreover, the laminated film of Comparative Example 2 has high haze. On the other hand, the laminated film of Example has a high refractive index, and in particular, the laminated film of Example 4 has excellent visibility and a high refractive index.

  The transparent conductive laminated film of the present invention can be used for various optical display devices that use the transparent conductive layer in a pattern, such as a personal computer, a television, a mobile phone (smart phone), electronic paper, a game machine, a mobile device, Touch panel (resistive film type touch panel, electrostatic capacity) used in combination with a display device (liquid crystal display device, plasma display device, organic or inorganic EL display device, etc.) in the display part of electric / electronic or precision equipment such as a clock and a calculator System touch panel). In particular, because of excellent visibility, it is useful for the upper electrode plate on the viewing side of a projected capacitive touch panel employing an ITO grid method.

Claims (15)

  A base film formed of a transparent material, and a hard coat formed of a cured product of a polymerizable composition that is laminated on at least one surface of the base film and includes nanometer-sized inorganic particles and a vinyl compound Layer and a transparent conductive layer formed in a part of the surface of the hard coat layer, wherein the vinyl compound is a silicon-free polyfunctional (meth) acrylate and silicon-containing A transparent conductive laminated film containing polyfunctional (meth) acrylate.   Silicon-free polyfunctional (meth) acrylate is a combination of 5-7 functional (meth) acrylate and 2-4 functional (meth) acrylate, and silicon-containing (meth) acrylate is silicone (meth) acrylate The transparent conductive laminated film according to claim 1.   The ratio of 5 to 7 functional (meth) acrylate and 2 to 4 functional (meth) acrylate is the former / the latter = 99/1 to 30/70, and the ratio of the silicon-containing polyfunctional (meth) acrylate is The transparent conductive laminated film according to claim 2, which is 0.1 to 30 parts by weight based on 100 parts by weight of the silicon-free polyfunctional (meth) acrylate.   The transparent conductive laminated film according to claim 1, wherein the polymerizable composition further contains a cellulose ester.   The transparent conductive laminated film according to claim 1, wherein the ratio (weight ratio) between the vinyl compound and the inorganic particles is the former / the latter = 50/50 to 10/90.   The transparent conductive laminated film according to claim 1, wherein a difference in total light transmittance between a region where the transparent conductive layer is formed and a region where the transparent conductive layer is not formed is 2% or less.   The transparent conductive laminated film according to claim 1, wherein the inorganic particles are metal oxide particles having an average primary particle size of 1 to 100 nm.   The transparent conductive laminated film according to any one of claims 1 to 7, wherein the inorganic particles contain titanium and / or zirconium.   The transparent conductive laminated film according to claim 1, wherein the difference in refractive index between the base film and the transparent conductive layer is 0.3 or more.   The transparent conductive laminated film according to claim 1, wherein the refractive index of the hard coat layer is larger than the refractive index of the base film and smaller than the refractive index of the transparent conductive layer.   11. The transparent according to claim 1, wherein the total light transmittance of the region where the transparent conductive layer is not formed is 80% or more, and the haze of the region where the transparent conductive layer is not formed is 5% or less. Conductive laminated film.   The transparent conductive laminated film according to claim 1, wherein the base film is formed of a polyester resin or a cellulose ester.   The transparent conductive film according to claim 1, which is a transparent electrode substrate of a touch panel formed by patterning a transparent conductive layer.   The hard coat layer is formed on at least one surface of the base film by coating, and then the transparent conductive layer is formed on the obtained hard coat layer by a physical or chemical vapor phase method. The manufacturing method of the transparent conductive laminated film of description.   A projected capacitive touch panel comprising the transparent conductive laminated film according to claim 1 as an electrode substrate.