JP2017220411A - Transparent conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film having excellent moisture/heat durability, and capable of preventing a poor appearance due to curvature from occurring.SOLUTION: A transparent conductive film 1 includes a transparent resin substrate 2; an adhesion layer 3; an optical regulation layer 4; and a transparent conductive layer 5 in this order. The optical regulation layer 4 has a hardness by JIS Z 2255 of 0.5 GPa or more. The optical regulation layer 4 is arranged on top of the adhesion layer 3 so as to have contact with the adhesion layer 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transparent conductive film, and more particularly to a transparent conductive film suitably used for optical applications.

  Conventionally, a transparent conductive film in which a transparent conductor layer made of indium tin composite oxide (ITO) or the like is formed is used for optical applications such as a touch panel.

  For example, a transparent conductive layer is patterned, and a transparent conductive film having an undercoat layer is disclosed in a non-pattern portion that does not have a transparent conductor layer (see, for example, Patent Document 1). The transparent conductive film of patent document 1 suppresses the reflectance difference of the pattern part and non-pattern part of a transparent conductor layer small, and makes the appearance favorable.

JP 2009-76432 A

  By the way, in recent years, with the versatility of touch panels, there has been a demand for wet heat durability in which the performance of the transparent conductive film is difficult to deteriorate when used in a high temperature and high humidity environment. For example, it is required that cracks do not occur even when left in an environment of 85 ° C. and 85% RH for a long time.

  Therefore, in the transparent conductive film of Patent Document 1, it is considered to improve wet heat durability by hardening the undercoat layer. However, if the undercoat layer is hardened, it tends to be brittle. Therefore, when the transparent conductive film is bent at the time of manufacture or use, cracks are formed in a streak shape, and only the crack portion looks white and a streak shape. As a result, a defect that the appearance of the transparent conductive film becomes defective occurs.

  An object of the present invention is to provide a transparent conductive film that has good wet heat durability and can suppress appearance defects due to bending.

  The present invention [1] includes a transparent resin base material, an adhesive layer, an optical adjustment layer, and a transparent conductive layer in this order, and the hardness of the optical adjustment layer in JIS Z 2255 is 0.5 GPa or more. And the optical adjustment layer includes a transparent conductive film disposed on one side in the thickness direction of the adhesive layer so as to be in contact with one side in the thickness direction of the adhesive layer.

  This invention [2] contains the transparent conductive film as described in [1] whose refractive index of the said contact bonding layer is 1.50 or more and 1.70 or less.

  This invention [3] contains the transparent conductive film as described in [1] or [2] whose thickness of the said contact bonding layer is 10 nm or more and 100 nm or less.

  This invention [4] contains the transparent conductive film as described in any one of [1]-[3] in which the said contact bonding layer consists of the adhesive composition containing aromatic dicarboxylic acid ester.

  The invention [5] includes the transparent conductive film according to [4], wherein the aromatic dicarboxylic acid ester is a reaction product of an aromatic dicarboxylic acid and a glycol, and the glycol contains propylene glycol. It is out.

  This invention [6] contains the transparent conductive film as described in any one of [1]-[5] which the said optical adjustment layer consists of a resin composition containing the polymer which has a saturated hydrocarbon ring. Yes.

  According to the transparent conductive film of the present invention, wet heat durability is good, and appearance defects due to bending can be suppressed.

FIG. 1 shows a cross-sectional view of a transparent conductive film according to an embodiment of the present invention. FIG. 2 shows a cross-sectional view of an embodiment in which the transparent conductive film shown in FIG. 1 is patterned. FIG. 3 is a schematic diagram when a wet heat durability test is performed on the transparent conductive film.

  With reference to FIG. 1, the transparent conductive film 1 of one Embodiment of this invention is demonstrated.

  In FIG. 1, the vertical direction of the paper is the vertical direction (thickness direction, first direction), the upper side of the paper is the upper side (one side in the thickness direction, the first direction), and the lower side of the paper is the lower side (thickness direction). The other side, the other side in the first direction). In FIG. 1, the left-right direction on the paper is the left-right direction (width direction, second direction orthogonal to the first direction), the left side of the paper is the left side (second direction one side), and the right side of the paper is the right side (second side in the second direction) ). In FIG. 1, the paper thickness direction is the front-rear direction (a third direction orthogonal to the first direction and the second direction), the front side of the paper is the front side (the third direction one side), and the back side of the paper surface is the rear side (the third direction). The other side). Specifically, it conforms to the direction arrow in each figure. Other figures also conform to FIG.

1. Transparent conductive film The transparent conductive film 1 has a film shape (including a sheet shape) having a predetermined thickness, extends in a predetermined direction (surface direction) orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface. Have. The transparent conductive film 1 is, for example, a component such as a base material for a touch panel provided in the image display device, that is, not an image display device. That is, the transparent conductive film 1 is a part for producing an image display device and the like, does not include an image display element such as an LCD module, and includes a transparent resin substrate 2, an adhesive layer 3, and an optical adjustment layer 4 described later. The device is composed of the transparent conductive layer 5 and is a device that can be distributed industrially and used industrially.

  Specifically, as shown in FIG. 1, the transparent conductive film 1 includes a transparent resin substrate 2, an adhesive layer 3, an optical adjustment layer 4, and a transparent conductive layer 5 in this order. More specifically, the transparent conductive film 1 is disposed on the transparent resin substrate 2, the adhesive layer 3 disposed on the upper surface (one surface in the thickness direction) of the transparent resin substrate 2, and the upper surface of the adhesive layer 3. The optical adjustment layer 4 and the transparent conductive layer 5 disposed on the upper surface of the optical adjustment layer 4 are provided. The transparent conductive film 1 preferably comprises a transparent resin substrate 2, an adhesive layer 3, an optical adjustment layer 4, and a transparent conductive layer 5.

2. Transparent resin base material The transparent resin base material 2 is a transparent base material for ensuring the mechanical strength of the transparent conductive film 1. That is, the transparent resin substrate 2 supports the transparent conductive layer 5 together with the adhesive layer 3 and the optical adjustment layer 4.

  The transparent resin substrate 2 is a polymer film having transparency, for example. Examples of the material for the transparent resin substrate 2 include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, for example, (meth) acrylic resins (acrylic resin and / or methacrylic resin) such as polymethacrylate. Olefin resins such as polyethylene, polypropylene, cycloolefin polymer (COP), for example, polycarbonate resin, polyether sulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, norbornene resin, etc. Is mentioned. The transparent resin substrate 2 can be used alone or in combination of two or more.

  From the viewpoint of transparency, wet heat durability, mechanical strength, and the like, preferably, a polyester resin is used, and more preferably, PET is used.

  The total light transmittance (JIS K 7375-2008) of the transparent resin substrate 2 is, for example, 80% or more, and preferably 85% or more.

  The thickness of the transparent resin substrate 2 is, for example, 2 μm or more, preferably 20 μm or more, from the viewpoint of mechanical strength, scratch resistance, and dot characteristics when the transparent conductive film 1 is used as a touch panel film. For example, it is 300 micrometers or less, Preferably, it is 150 micrometers or less. The thickness of the transparent resin substrate 2 can be measured using, for example, a micro gauge thickness meter.

  In addition, the anti-blocking layer, the hard-coat layer, etc. may be provided in the upper surface and / or lower surface of the transparent resin base material 2 as needed.

3. Adhesive Layer The adhesive layer 3 is a layer for reducing appearance defects that occur when the transparent conductive film 1 is bent. Moreover, it is also a layer for improving the adhesiveness between the transparent resin substrate 2 and the optical adjustment layer 4.

  The adhesive layer 3 has a film shape (including a sheet shape) and is disposed, for example, on the entire upper surface of the transparent resin substrate 2 so as to be in contact with the upper surface of the transparent resin substrate 2. More specifically, the adhesive layer 3 is disposed between the transparent resin substrate 2 and the optical adjustment layer 4 so as to contact the upper surface of the transparent resin substrate 2 and the lower surface of the optical adjustment layer 4. .

  The adhesive layer 3 is formed from an adhesive composition.

  The adhesive composition contains, for example, an aromatic dicarboxylic acid ester. An aromatic dicarboxylic acid ester is a reaction product of an aromatic dicarboxylic acid and an alcohol such as glycol.

  The aromatic dicarboxylic acid is preferably phthalic acid.

  Examples of glycol include ethylene glycol (EG) and propylene glycol (PG). The glycol preferably contains at least propylene glycol, and more preferably contains both ethylene glycol and propylene glycol, from the viewpoint of suppressing poor appearance due to bending.

  The aromatic dicarboxylic acid ester is preferably a phthalic acid ester, which is a reaction product of phthalic acid and glycol, from the viewpoint of suppressing poor appearance due to bending, and more preferably a reaction between phthalic acid and glycol. Products.

  In addition to the aromatic dicarboxylic acid ester, the adhesive composition may contain, for example, organic components such as a (meth) acrylic acid component, an oxazoline component, a melamine component, and a glycol component.

  The adhesive composition can also contain an inorganic component in addition to the organic component.

  As the inorganic component, a suitable material can be selected according to the refractive index required of the adhesive layer 3, and for example, a metal oxide composed of a SiOx component (such as silica), for example, zirconium oxide, titanium oxide, zinc oxide or the like. Examples thereof include carbonates such as calcium carbonate. Preferably, a metal oxide is mentioned, More preferably, a zirconium oxide and a titanium oxide are mentioned, More preferably, a zirconium oxide is mentioned.

  The refractive index of the adhesive layer 3 is, for example, 1.50 or more, preferably 1.55 or more, more preferably 1.60 or more, and for example, 1.70 or less, preferably 1.65 or less. It is. By making the refractive index of the adhesive layer 3 in the above range, the visual recognition of the wiring pattern can be further suppressed. Moreover, the appearance defect due to the bending of the transparent conductive film 1 can be further suppressed. The refractive index is measured by an Abbe refractometer.

  The thickness of the adhesive layer 3 is, for example, 10 nm or more, preferably 20 nm or more, more preferably 25 nm or more, and for example, 100 nm or less, preferably 80 nm or less, more preferably 70 nm or less. By making the thickness of the adhesive layer 3 in the above range, the adhesiveness between the transparent resin substrate 2 and the optical adjustment layer 4 can be improved, and the fluctuation of optical characteristics with these layers can be reduced, and the appearance Defects can be further suppressed. The thickness of the adhesive layer 3 can be measured using, for example, an instantaneous multi-photometry system.

4). Optical Adjustment Layer The optical adjustment layer 4, together with the adhesive layer 3, suppresses the visual recognition of the wiring pattern in the transparent conductive layer 5, while ensuring excellent transparency in the transparent conductive film 1. It is a layer for adjusting optical physical properties (for example, refractive index).

  The optical adjustment layer 4 has a film shape (including a sheet shape). For example, the optical adjustment layer 4 is disposed on the entire upper surface of the adhesive layer 3 so as to be in contact with the upper surface of the adhesive layer 3. More specifically, the optical adjustment layer 4 is disposed between the adhesive layer 3 and the transparent conductive layer 5 so as to be in contact with the upper surface of the adhesive layer 3 and the lower surface of the transparent conductive layer 5.

  The optical adjustment layer 4 is formed from an optical adjustment composition.

  The optical adjustment composition only needs to have a hardness of 0.5 GPa or more in the optical adjustment layer 4 to be described later. From the viewpoint of the hardness of the optical adjustment layer 4, preferably (1) a saturated hydrocarbon ring. And a resin composition containing a polymer having an aromatic ring and (2) a resin composition containing a polymer having an aromatic ring. More preferably, the resin composition containing the polymer which has a saturated hydrocarbon ring is mentioned.

  (1) The polymer having a saturated hydrocarbon ring is preferably an epoxy resin.

  Examples of the saturated hydrocarbon ring include a cyclohexane ring and a norbornene ring.

  As a monomer which comprises an epoxy resin, the monomer which has a saturated hydrocarbon ring is mentioned, for example. Specific examples include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and hydrogenated bisphenol A diglycyl ether.

  Moreover, as a monomer which comprises an epoxy resin, in addition to the monomer which has a saturated hydrocarbon ring, the monomer which does not have a saturated hydrocarbon ring may be included. Examples of such monomers include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, naphthalene diglycidyl ether, biphenyl diglycidyl ether, and triglycidyl isocyanurate.

  The epoxy resin is preferably rubber-modified. That is, preferably, a rubber-modified epoxy resin is used.

  Examples of the rubber include polybutadiene (1,2-polybutadiene, 1,4-polybutadiene, etc.), styrene / butadiene rubber, butyl rubber, polyisobutylene rubber, chloroprene rubber, nitrile rubber, acrylic rubber, and the like. Preferably, polybutadiene is used.

  The weight average molecular weight of the polymer having a saturated hydrocarbon ring is, for example, 1000 or more, preferably 1500 or more, and for example, 10,000 or less, preferably 5000 or less. The molecular weight is measured by gel permeation chromatography (GPC) and is determined by standard polystyrene conversion value.

  From the viewpoint of hardness, the resin composition containing a polymer having a saturated hydrocarbon ring preferably contains a curing agent in addition to the polymer.

  Examples of the curing agent include antimony curing agents such as antimony trioxide, benzylmethyl p-methoxycarbonyloxyphenylsulfonium hexafluoroantimonate, and hexafluoroantimonate, such as p-methylthiophenol and naphthol compounds. .

  When the optical adjustment composition contains a curing agent, the content of the curing agent with respect to 100 parts by mass of the polymer having a saturated hydrocarbon ring is, for example, 0.005 parts by mass or more, preferably 0.01 parts by mass or more. Also, for example, it is 0.5 parts by mass or less, preferably 0.1 parts by mass or less.

  (2) Examples of the resin composition containing a polymer having an aromatic ring include a polyphenylene ether composition, an acrylic composition, and a polysiloxane composition.

  Examples of the aromatic ring include a benzene ring and a naphthalene ring.

  The polyphenylene ether composition contains polyphenylene ether.

  Examples of the polyphenylene ether include a polymer having a phenylene ether unit represented by the following formula (1).

In Formula (1), each R ¹ independently represents a halogen atom or an alkyl group, phenyl group or alkoxy group which may have a substituent. R ¹ preferably represents each independently an alkyl group or a phenyl group, more preferably an alkyl group, and still more preferably an alkyl group having 7 or less carbon atoms.

R ² independently represents a hydrogen atom, a halogen atom, or an alkyl group, a phenyl group or an alkoxy group which may have a substituent. R ² preferably represents a hydrogen atom.

Examples of the substituent represented by R ¹ and R ² include a halogen atom and an amino group.

  Examples of the phenylene ether unit include 2,6-dimethyl-1,4-phenylene ether unit and 2,3,6-trimethyl-1,4-phenylene ether unit.

  The polyphenylene ether may have a glycidyl ether skeleton as a main chain terminal or a side chain.

  The acrylic composition contains a polymer (acrylic polymer) of a monomer mainly composed of (meth) acrylic acid ester.

  The (meth) acrylic acid ester is a methacrylic acid ester and / or an acrylic acid ester, and specifically includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( Isopropyl methacrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, (meth) acrylic acid 1 to 14 carbon atoms having a straight or branched chain such as hexyl, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, etc. Preferable examples include (meth) acrylic acid alkyl ester having 1 to 4) alkyl moiety.

  Examples of (meth) acrylic acid esters include hydroxyl group-containing (meth) acrylic acid esters such as 2-hydroxyethyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate.

  As a monomer component, in addition to (meth) acrylic acid ester, a monomer copolymerizable with (meth) acrylic acid ester having an aromatic ring is contained. Examples of such a monomer include alkenyl aromatic monomers such as styrene, α-methylstyrene, vinyltoluene, and divinylbenzene.

  As the monomer component, in addition to the above, for example, acrylic acid, methacrylic acid, for example, α, β-ethylenically unsaturated carboxylic acid ester such as dimethyl fumarate, dibutyl fumarate, dimethyl maleate, etc., for example, crotonic acid, maleic Even if it contains α, β-ethylenically unsaturated carboxylic acid such as acid and fumaric acid, for example, dienes such as 1,3-butadiene and 1,4-hexadiene, for example, olefin such as ethylene and propylene Good.

  The polysiloxane-based composition contains polysiloxane having an aromatic ring in the side chain.

  Examples of such polysiloxane include a reaction product obtained by hydrosilylation reaction of a siloxane having a hydrosilyl group and an organic compound having an alkenyl group.

  Examples of the siloxane having a hydrosilyl group include a polysiloxane having a methylhydrogensiloxane unit and a dimethylsiloxane unit, and a polysiloxane having a methylhydrogensiloxane unit and a methylphenylsiloxane unit.

  Examples of the organic compound having an alkenyl group include an aromatic hydrocarbon compound containing an alkenyl group, and specific examples include divinylbenzene.

  The resin composition containing a polymer having an aromatic ring may contain an isocyanate compound in addition to the above components from the viewpoints of heat resistance and expansion resistance. Examples of the isocyanate compound include hexamethylene diisocyanate, tolylene diisocyanate, bis (4-cyanatephenyl) methane, 2,2-bis (4-cyanatephenyl) propane, and allylisocyanate. Further, cyanate resins using these as raw materials, trimethylolpropane adducts, isocyanurates, and the like are also included.

  The optical adjustment composition can also contain particles in addition to the above components. As the particles, a suitable material can be selected according to the refractive index required of the optical adjustment layer 4, and examples thereof include inorganic particles and organic particles. Examples of the inorganic particles include silica particles, for example, metal oxide particles made of zirconium oxide, titanium oxide, zinc oxide, and the like, for example, carbonate particles such as calcium carbonate. Examples of the organic particles include crosslinked acrylic resin particles.

  When the optical adjustment composition is heated to 90 ° C., it is, for example, 30 seconds or longer, preferably 50 seconds or longer, and for example, 100 seconds or shorter, preferably 80 seconds or shorter. . By setting the gelation time within the above range, the processing speed can be improved. The gelation time is measured, for example, by placing the optical adjustment composition on a plate whose surface temperature is set to 90 ° C. using a gelation tester and measuring the time until the optical adjustment composition is cured. Can be sought.

  The hardness of the optical adjustment layer 4 is 0.5 GPa or more. Preferably, it is 0.6 GPa or more, more preferably 0.7 GPa or more, for example, 1.0 GPa or less, preferably 0.9 GPa or less. By setting the hardness of the optical adjustment layer 4 within the above range, the wet heat durability of the transparent conductive film 1 is excellent. In particular, even when left in a high-humidity and high-temperature environment for a long time, it is possible to suppress the occurrence of cracks and further suppress a significant increase in the surface resistance value after being left.

  The hardness of the optical adjustment layer 4 is, for example, the hardness of the optical adjustment layer 4 when the optical adjustment layer 4 with a thickness of 30 nm is arranged on a PET film with a thickness of 50 μm. JIS Z 2255 (2003, ultrafine It can be measured according to a small load hardness test method).

  The refractive index of the optical adjustment layer 4 is, for example, 1.20 or more, preferably 1.30 or more, and for example, 1.60 or less, preferably 1.55 or less.

  The refractive index of the optical adjustment layer 4 is preferably lower than the refractive index of the adhesive layer 3, and the difference between the refractive index with the adhesive layer 3 and the refractive index of the optical adjustment layer 4 is, for example, 0.05 or more. Preferably, it is 0.10 or more, more preferably 0.12 or more, for example, 0.60 or less, preferably 0.50 or less, and more preferably 0.30 or less.

  By setting the refractive index of the optical adjustment layer 4 within the above range, the visual recognition of the wiring pattern can be further suppressed. Moreover, the appearance defect due to the bending of the transparent conductive film 1 can be further suppressed.

  The thickness of the optical adjustment layer 4 is, for example, 1 nm or more, preferably 5 nm or more, more preferably 20 nm or more, and for example, 100 nm or less, preferably 50 nm or less, more preferably 40 nm or less. The thickness of the optical adjustment layer 4 can be measured using, for example, an instantaneous multi-photometry system.

  The ratio of the thickness of the optical adjustment layer 4 to the thickness of the adhesive layer 3 (optical adjustment layer 4 / adhesion layer 3) is, for example, 0.7 or more, preferably 0.8 or more. 1 or less, preferably 1.0 or less.

5). Transparent conductive layer The transparent conductive layer 5 is a conductive layer for forming the pattern portion 7 by forming it in a wiring pattern in a later step.

  The transparent conductive layer 5 is the uppermost layer of the transparent conductive film 1 and has a film shape (including a sheet shape). The transparent conductive layer 5 is in contact with the upper surface of the optical adjustment layer 4 and the upper surface of the optical adjustment layer 4. So that it is arranged.

  The material of the transparent conductive layer 5 is, for example, at least one selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. And metal oxides containing these metals. If necessary, the metal oxide may be further doped with a metal atom shown in the above group.

  Examples of the material of the transparent conductive layer 5 include indium-containing oxides such as indium tin composite oxide (ITO), for example, antimony-containing oxides such as antimony tin composite oxide (ATO), and preferably indium The containing oxide, more preferably, ITO is used.

When ITO is used as the material of the transparent conductive layer 5, the tin oxide (SnO ₂ ) content is, for example, 0.5% by mass or more, preferably with respect to the total amount of tin oxide and indium oxide (In ₂ O ₃ ). Is 3% by mass or more, and for example, 15% by mass or less, preferably 13% by mass or less. By setting the content of tin oxide to the above lower limit or more, the durability of the ITO layer can be further improved. By making the content of tin oxide not more than the above upper limit, crystal conversion of the ITO layer can be facilitated, and the stability of transparency and surface resistance can be improved.

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

  The refractive index of the transparent conductive layer 5 is, for example, 1.85 or more, preferably 1.95 or more, and for example, 2.20 or less, preferably 2.10 or less.

  The thickness of the transparent conductive layer 5 is, for example, 10 nm or more, preferably 15 nm or more, and for example, 30 nm or less, preferably 25 nm or less. The thickness of the transparent conductive layer 5 can be measured using, for example, an instantaneous multi-photometry system.

  The transparent conductive layer 5 may be either crystalline or amorphous, or may be a mixture of crystalline and amorphous. The transparent conductive layer 5 is preferably made of a crystalline material, more specifically, a crystalline ITO layer. Thereby, the transparency of the transparent conductive layer 5 can be improved and the surface resistance of the transparent conductive layer 5 can be further reduced.

  The transparent conductive layer 5 is a crystalline film. For example, when the transparent conductive layer 5 is an ITO layer, it is immersed in 20 ° C. hydrochloric acid (concentration 5% by mass) for 15 minutes, washed with water and dried, 15 mm This can be determined by measuring the resistance between terminals. In this specification, the ITO layer is assumed to be crystalline when the resistance between terminals of 15 mm is 10 kΩ or less after immersion, washing and drying in hydrochloric acid (20 ° C., concentration: 5 mass%).

6). Next, a method for producing the transparent conductive film 1 will be described.

  In order to manufacture the transparent conductive film 1, for example, the adhesive layer 3, the optical adjustment layer 4, and the transparent conductive layer 5 are provided in this order on one surface of the transparent resin substrate 2. That is, the adhesive layer 3 is provided on the upper surface of the transparent resin substrate 2, the optical adjustment layer 4 is then provided on the upper surface of the adhesive layer 3, and then the transparent conductive layer 5 is provided on the upper surface of the optical adjustment layer 4. Details will be described below.

  First, a known or commercially available transparent resin substrate 2 is prepared.

  Thereafter, as necessary, from the viewpoint of adhesion between the transparent resin substrate 2 and the adhesive layer 3, the surface of the transparent resin substrate 2 is subjected to, for example, sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion. Etching treatment such as oxidation and undercoating treatment can be performed. Moreover, the transparent resin base material 2 can be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like.

  Next, the adhesive layer 3 is provided on the upper surface of the transparent resin substrate 2. For example, the adhesive composition 3 is formed on the upper surface of the transparent resin substrate 2 by wet-coating the adhesive composition on the upper surface of the transparent resin substrate 2.

  Specifically, for example, a liquid adhesive composition is prepared, and then the adhesive composition is applied to the upper surface of the transparent resin substrate 2 and dried.

  The coating method can be appropriately selected according to the transparent substrate. Examples thereof include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, and an extrusion coating method.

  A drying temperature is 50 degreeC or more, for example, Preferably, it is 60 degreeC or more, More preferably, it is 70 degreeC or more, for example, 200 degrees C or less, Preferably, it is 150 degrees C or less, More preferably, it is 100 degrees C or less.

  The drying time is, for example, 0.5 minutes or more, preferably 1 minute or more, for example, 60 minutes or less, preferably 20 minutes or less.

  By the application and drying described above, the adhesive composition is formed in a film shape on the upper surface of the transparent resin substrate 2.

  Next, the optical adjustment layer 4 is provided on the upper surface of the adhesive layer 3. For example, the optical adjustment layer 4 is formed on the upper surface of the adhesive layer 3 by wet-coating the optical adjustment composition on the upper surface of the adhesive layer 3.

  Specifically, for example, if necessary, a diluted solution (varnish) obtained by diluting the optical adjustment composition with a solvent is prepared, and then the diluted solution is applied to the upper surface of the adhesive layer 3 and the diluted solution is dried. .

  Examples of the solvent include an organic solvent and an aqueous solvent (specifically, water), and an organic solvent is preferable. Examples of the organic solvent include alcohol compounds such as methanol, ethanol, and isopropyl alcohol, ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester compounds such as ethyl acetate and butyl acetate, and propylene glycol monomethyl ether (PGME). ) And the like, for example, aromatic compounds such as toluene and xylene. These solvents can be used alone or in combination of two or more. Preferably, a ketone compound is used.

  The solid content concentration in the diluted solution is, for example, 1% by mass or more, preferably 10% by mass or more, and for example, 30% by mass or less, preferably 20% by mass or less.

  The conditions such as the preparation, application and drying of the optical adjustment composition are the same as the conditions such as the preparation, application and drying exemplified in the adhesive composition.

  When the resin of the resin composition contains an active energy ray curable resin, the active energy ray curable resin is cured by irradiating the active energy ray after drying the diluted solution.

  Next, the transparent conductive layer 5 is provided on the upper surface of the optical adjustment layer 4. For example, the transparent conductive layer 5 is formed on the upper surface of the optical adjustment layer 4 by a dry method.

  Examples of the dry method include a vacuum deposition method, a sputtering method, and an ion plating method. Preferably, a sputtering method is used. By this method, the thin transparent conductive layer 5 can be formed.

  When the sputtering method is employed, the target material includes the above-described inorganic material constituting the transparent conductive layer 5, and preferably ITO. The tin oxide concentration of ITO is, for example, 0.5% by mass or more, preferably 3% by mass or more, and, for example, 15% by mass or less, preferably from the viewpoint of durability and crystallization of the ITO layer. 13 mass% or less.

  Examples of the sputtering gas include an inert gas such as Ar. Moreover, reactive gas, such as oxygen gas, can be used together as needed. In the case of using the reactive gas in combination, the flow rate ratio of the reactive gas is not particularly limited, but is, for example, 0.1 flow% or more and 5 flow% or less with respect to the total flow ratio of the sputtering gas and the reactive gas.

  The atmospheric pressure during sputtering is, for example, 1 Pa or less, preferably 0.1 Pa or more and 0.7 Pa or less, from the viewpoint of suppressing a decrease in sputtering rate, discharge stability, or the like.

  The power source used for the sputtering method may be, for example, any of a DC power source, an AC power source, an MF power source, and an RF power source, or a combination thereof.

  Moreover, in order to form the transparent conductive layer 5 having a desired thickness, sputtering may be performed a plurality of times by appropriately setting a target material, sputtering conditions, and the like.

  Thereby, the transparent conductive film 1 is obtained.

  Next, a crystal conversion treatment is performed on the transparent conductive layer 5 of the transparent conductive film 1 as necessary.

  Specifically, the transparent conductive film 1 is subjected to heat treatment in the atmosphere.

  The heat treatment can be performed using, for example, an infrared heater or an oven.

  The heating temperature is, for example, 100 ° C. or more, preferably 120 ° C. or more, and for example, 200 ° C. or less, preferably 160 ° C. or less. By setting the heating temperature within the above range, it is possible to ensure crystal conversion while suppressing thermal damage of the transparent resin substrate 2 and impurities generated from the transparent resin substrate 2.

  The heating time is appropriately determined according to the heating temperature, and is, for example, 10 minutes or longer, preferably 30 minutes or longer, and for example, 5 hours or shorter, preferably 3 hours or shorter.

  Thereby, the transparent conductive film 1 provided with the crystallized transparent conductive layer 5 is obtained.

  If necessary, the transparent conductive layer 5 may be formed in a stripe pattern or the like by a known etching method before or after the crystal conversion treatment, as shown in FIG.

  For example, the etching is performed by disposing a covering portion (masking tape or the like) on the transparent conductive layer 5 so as to correspond to the non-pattern portion 6 and the pattern portion 7 and exposing the transparent conductive layer 5 (non-pattern portion) from the covering portion. 6) is etched using an etching solution. Examples of the etching solution include acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, succinic acid, phosphoric acid, and mixed acids thereof. Thereafter, the covering portion is removed from the upper surface of the transparent conductive layer 5 by, for example, peeling.

  Moreover, in the said manufacturing method, while conveying the transparent resin base material 2 by a roll-to-roll system, the adhesive layer 3, the optical adjustment layer 4, and the transparent conductive layer 5 are arranged in this order on the upper surface of the transparent resin base material 2. These layers may be formed, or a part or all of these layers may be formed by a batch system (single wafer system).

  The total thickness of the obtained transparent conductive film 1 is, for example, 2 μm or more, preferably 20 μm or more, and for example, 300 μm or less, preferably 150 μm or less.

(Function and effect)
The transparent conductive film 1 includes a transparent resin base material 2, an adhesive layer 3, an optical adjustment layer 4, and a transparent conductive layer 5 in this order, and the hardness of the optical adjustment layer 4 is 0.5 GPa or more. . Therefore, even when used in a high temperature and high humidity environment, the performance of the transparent conductive film 1 can be suppressed, and the wet heat durability is excellent. Specifically, the occurrence of cracks can be suppressed even when left in an environment of 85 ° C. and 85% RH for a long time.

  The optical adjustment layer 4 is disposed on the upper side of the adhesive layer 3 so as to be in contact with the upper surface of the adhesive layer 3. Therefore, appearance defects due to bending can be suppressed.

  In particular, in a conventional transparent conductive film comprising a transparent resin base material / optical adjustment layer / transparent conductive layer, from the viewpoint of wet heat durability, when the optical adjustment layer 4 is hardened, a crack occurs in the optical adjustment layer 4 due to bending. Alternatively, only the optical adjustment layer 4 remains bent without recovering to the state before bending. As a result, a gap (air layer) is generated between the optical adjustment layer 4 and the transparent resin base material 2 under the optical adjustment layer 4, and a white portion (white streak or the like) is generated due to a difference in refractive index between the air layer and the optical adjustment layer 4. ) Is observed in the transparent film. On the other hand, in the transparent conductive film 1 of this embodiment, it is arrange | positioned above the contact bonding layer 3 so that the upper surface of the contact bonding layer 3 may be contacted. Therefore, even if the optical adjustment layer 4 is cracked due to the bending of the transparent conductive film 1 or only the optical adjustment layer 4 is bent, the adhesive layer 3 is bent and deformed into the optical adjustment layer 4. Can follow. Therefore, generation | occurrence | production of a space | gap (air layer) can be suppressed between the optical adjustment layer 4 and the adhesive layer 3 of the lower layer, or a space | gap can be made small. As a result, appearance defects due to bending can be suppressed.

  Further, the adhesive layer 3 is disposed on the entire upper surface of the transparent resin substrate 2 so as to be in contact with the upper surface of the transparent resin substrate 2. Therefore, generation | occurrence | production of the space | gap of the contact bonding layer 3 and the transparent resin base material 2 by bending can also be suppressed. As a result, appearance defects due to bending can be more reliably suppressed.

  The transparent conductive film 1 is provided in an optical device, for example. Examples of the optical device include an image display device. When the transparent conductive film 1 is provided in an image display device (specifically, an image display device having an image display element such as an LCD module), the transparent conductive film 1 is used as a base material for a touch panel, for example. . Examples of the touch panel format include various systems such as an optical system, an ultrasonic system, a capacitive system, and a resistive film system, and the touch panel is particularly preferably used for a capacitive touch panel.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, this invention is not limited to an Example and a comparative example at all. In addition, specific numerical values such as a blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and a blending ratio corresponding to them ( Substituting the upper limit value (numerical value defined as “less than” or “less than”) or the lower limit value (number defined as “greater than” or “exceeded”) such as content ratio), physical property values, parameters, etc. be able to.

Example 1
An adhesive composition containing phthalic acid ester (phthalic acid / ethylene glycol / propylene glycol reactant), methacrylic acid, oxazoline, ethylene glycol, propylene glycol, melamine, and zirconium oxide was prepared, and a polyethylene terephthalate film (PET) having a thickness of 50 μm An adhesive layer having a thickness of 35 nm was formed by applying and drying on one surface of a transparent resin substrate made of a film. The refractive index of the adhesive layer was 1.65.

  Next, 10 parts by mass of a rubber-modified epoxy resin (“Adekafilterra BUR-12A”, manufactured by ADEKA, weight average molecular weight 2000) and an antimony-based curing agent (“Adekafilterra BUR-12B”, manufactured by ADEKA) 0.001 An optical adjustment composition was prepared by mixing parts by mass. The gelation time at 90 ° C. of the optical adjustment composition was 60 seconds.

  The optical adjustment composition was mixed with 90 parts by mass of methyl isobutyl ketone to prepare an optical adjustment composition varnish. An optical adjustment layer having a thickness of 30 nm was formed by applying the varnish of the optical adjustment composition on the adhesive layer and then drying. The refractive index of the optical adjustment layer was 1.53.

  Next, an ITO layer (transparent conductive layer) having a thickness of 20 nm was formed on the upper surface of the optical adjustment layer by sputtering. Specifically, an ITO target made of a sintered body of 90% by mass of indium oxide and 10% by mass of tin oxide is sputtered in a vacuum atmosphere of atmospheric pressure 0.4 Pa into which argon gas 98% and oxygen gas 2% are introduced. did. The refractive index of the ITO layer was 2.00.

  Thereby, the transparent conductive film was manufactured.

Example 2
A transparent resin comprising a polyethylene terephthalate film (PET film) having a thickness of 50 μm prepared by preparing an adhesive composition containing phthalic acid ester (phthalic acid / ethylene glycol reactant), methacrylic acid, oxazoline, ethylene glycol, melamine, and titanium oxide An adhesive layer having a thickness of 35 nm was formed by applying and drying on one surface of the substrate. The refractive index of the adhesive layer was 1.65.

  A transparent conductive film was produced in the same manner as in Example 1 except that this adhesive layer was formed.

Comparative Example 1
A transparent conductive film was produced in the same manner as in Example 1 except that the adhesive layer was not provided.

Comparative Example 2
An optical adjustment composition was prepared by mixing a methoxylated methylol melamine resin, a polyester having an isophthalic acid unit, a maleate and a silicone. The optical adjustment composition was mixed with 90 parts by mass of methyl isobutyl ketone to prepare an optical adjustment composition varnish. An optical adjustment layer having a thickness of 30 nm was formed by applying and drying the varnish of the optical adjustment composition on one surface of a transparent resin substrate made of a PET film having a thickness of 50 μm. The refractive index of the optical adjustment layer was 1.53.

  Next, in the same manner as in Example 1, an ITO layer having a thickness of 20 nm was formed on the optical adjustment layer to produce a transparent conductive film.

(1) Thickness The PET film was measured using a micro gauge thickness meter (manufactured by Mitutoyo Corporation).

  The adhesive layer, the optical adjustment layer, and the transparent conductive layer were calculated based on the waveform of the interference spectrum using an instantaneous multi-photometry system (“MCPD2000”, manufactured by Otsuka Electronics Co., Ltd.).

(2) Refractive index The refractive index of each layer is defined by the refractometer using an Abbe refractometer (manufactured by Atago Co., Ltd.) so that the measurement light is incident on the measurement surface at 25 ° C. Measurement was carried out by the measurement method.

(3) Hardness of optical adjustment layer The hardness of the optical adjustment layer was measured in accordance with JIS Z 2255 (2003, ultra-micro load hardness test method).

  Specifically, samples for hardness measurement were prepared in which an optical adjustment layer having a thickness of 30 nm described in Examples or Comparative Examples was provided on the upper surface of a PET film having a thickness of 50 μm. Ultra fine load hardness (HTL) was measured by pressing a triangular cone indenter against the upper surface of the optical adjustment layer of these samples. Note that the indentation depth of the indenter was 20 nm. The results are shown in Table 1.

(4) Wet heat durability The ITO layer was crystallized by heating the transparent conductive film of each Example and each comparative example at 150 degreeC for 1 hour.

  Next, after a masking tape having a width of 2 mm was attached at intervals of 10 mm, the ITO layer at the non-attached portion of the masking tape was etched and patterned into a striped (width 10 mm) ITO layer (see FIG. 3). The masking tape was peeled off, and the transparent conductive film 1 was further heated at 150 ° C. for 30 minutes.

  Subsequently, the glass plate 9 was arrange | positioned through the adhesive 8 in the ITO layer 5 of the transparent conductive film 1 (refer FIG. 3). This transparent conductive film with a glass plate was put into a high-temperature humidity controller (“LHL-113”, manufactured by Espec Corp.) and left in an environment of 85 ° C. and 85% RH for 240 hours (high-temperature and high-humidity test). Then, the adhesive 8 and the glass plate 9 were peeled off.

  The surface of the transparent conductive film after the test was observed with the naked eye. The case where the white spot was clearly observed was evaluated as x, and the case where the white spot was hardly observed was evaluated as ◯. The results are shown in Table 1.

(5) Bending test In accordance with JIS K 5600, a mandrel test (type I, mandrel diameter 16 mm or 12 mm) was carried out, and the transparent conductive film of each example and each comparative example was bent at 180 degrees. The surface (appearance) of the transparent conductive film after the test was observed with the naked eye.

  In the case of both mandrel diameters of 16 mm and 12 mm, the case where white streaks were observed in the bent portion was evaluated as x. When a mandrel diameter of 16 mm was used, no white streak was observed at the bent portion, but when a mandrel diameter of 12 mm was used, a case where a white streak was observed was evaluated as Δ. In both cases of mandrel diameters of 16 mm and 12 mm, a case where no white streak was observed was evaluated as ◯. The results are shown in Table 1.

  In addition, in the transparent conductive film of Comparative Example 1 evaluated as x, when the cross section of the white streak portion was observed with SEM, the optical adjustment layer was bent so as to be convex upward, and the optical adjustment layer and the PET film were A large void (air layer) was generated between them.

  On the other hand, in the transparent conductive film of Example 1 and 2 evaluated as (circle), when the cross section of the white streak part was observed by SEM, the optical adjustment layer was bent so that it might become convex upwards. However, since the adhesion layer followed the optical adjustment layer, almost no void was generated between the optical adjustment layer and the PET film.

DESCRIPTION OF SYMBOLS 1 Transparent conductive film 2 Transparent resin base material 3 Adhesive layer 4 Optical adjustment layer 5 Transparent conductive layer

Claims (6)

A transparent resin base material, an adhesive layer, an optical adjustment layer, and a transparent conductive layer are provided in this order,
The optical adjustment layer has a hardness in JIS Z 2255 of 0.5 GPa or more,
The said optical adjustment layer is arrange | positioned at the thickness direction one side of the said adhesive layer so that it may contact with the thickness direction one side of the said adhesive layer, The transparent conductive film characterized by the above-mentioned.   The transparent conductive film according to claim 1, wherein the adhesive layer has a refractive index of 1.50 or more and 1.70 or less.   The transparent conductive film according to claim 1, wherein a thickness of the adhesive layer is 10 nm or more and 100 nm or less.   The transparent conductive film according to any one of claims 1 to 3, wherein the adhesive layer is made of an adhesive composition containing an aromatic dicarboxylic acid ester.   The transparent conductive film according to claim 4, wherein the aromatic dicarboxylic acid ester is a reaction product of an aromatic dicarboxylic acid and a glycol, and the glycol contains propylene glycol. The said optical adjustment layer consists of a resin composition containing the polymer which has a saturated hydrocarbon ring, The transparent conductive film as described in any one of Claims 1-5 characterized by the above-mentioned.

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