JP6971558B2 - Transparent conductive film and display device with touch function - Google Patents

Description

The present invention relates to a transparent conductive film and a display device with a touch function.

In recent years, integration of the touch module function and the display display function has been studied for the purpose of improving the display display characteristics and making the device thinner. For example, a method of incorporating a touch sensor inside a part of a member of a display module and a method of applying a transparent conductive film to a part of an optical functional film for a display device such as a circularly polarizing plate and using it as a touch sensor have been studied. ing. An isotropic material is used as the base material when the transparent conductive sensor is incorporated inside the circularly polarizing plate, and a λ / 4 retardation plate is used as the base material when the conductive film is applied to a part of the circularly polarizing plate. The method used as is being studied.

When processing a transparent film, sufficient handleability (prevention of sticking between films, stiffness (strength) of the film, etc.) is required to ensure a high yield. Generally, as one method for improving the handleability, it is conceivable to increase the roughness of the film surface and improve the slipperiness. For example, a technique has been proposed in which a transparent conductive layer is provided on a λ / 4 retardation film, and a light scattering layer is provided on the opposite side to prevent scratches during processing (Patent Document 1).

Patent No. 4059883

However, in a configuration in which a touch sensor is incorporated inside a circularly polarizing plate or a configuration in which a transparent conductive film for a touch sensor is provided on a part of the circularly polarizing plate, the antireflection function due to circularly polarized light may not be affected as much as possible. Desired. In the above technology, there is a light scattering layer as an anti-blocking functional layer, but by increasing the surface roughness, light scattering is increased and it becomes a polarization scattering factor, which causes a problem that the antireflection function is deteriorated. ing. As described above, the provision of the anti-blocking function and the securing of the antireflection function are in a trade-off relationship with each other, and there is a demand for a transparent conductive film that achieves both at a sufficient level.

In view of the above viewpoint, the present invention provides a transparent conductive film having sufficient handleability and not impairing low reflection characteristics even when incorporated in a display module, and a display device with a touch function using the transparent conductive film. With the goal.

As a result of diligent studies to solve the above problems, the present inventors have found that the above object can be achieved by adopting the following configuration, and have arrived at the present invention.

The present invention comprises a transparent film substrate having a front phase difference of 200 nm or less.
An anti-blocking layer provided on at least one of the first main surface side and the second main surface side of the transparent film base material,
A transparent conductive layer provided on at least one of the surface side of the anti-blocking layer opposite to the transparent film base material side and the surface side of the transparent film base material opposite to the anti-blocking layer side is provided.
The anti-blocking layer is a cured product layer of a resin composition containing a binder resin and particles.
The anti-blocking layer has a flat portion and a raised portion due to the particles on the surface opposite to the transparent film base material side.
The mode particle size of the particles is larger than the thickness of the flat portion of the anti-blocking layer.
The present invention relates to a transparent conductive film in which the refractive index np of the particles and the refractive index nb of the binder resin satisfy the following relationship.
| Np-nb | <0.14

In the transparent conductive film, the anti-blocking layer has a raised portion due to the particles, and the most frequent particle diameter of the particles is larger than the flat portion of the anti-blocking layer, so that slipperiness and blocking resistance are obtained. It is excellent in terms of handling and can exhibit good handling properties. Further, since the absolute value of the difference between the refractive index np of the particles and the refractive index nb of the binder resin forming the anti-blocking layer is made small, light scattering and polarization elimination due to the difference in the refractive index between the two are prevented. As a result, it is possible to impart excellent optical characteristics including low reflection characteristics to the display device even when it is incorporated inside the display module.

It is preferable that the maximum roughness Rz of the surface of the anti-blocking layer on the side opposite to the transparent film substrate side is 0.3 μm or more and 2.5 μm or less. As a result, handleability and low reflection characteristics can be exhibited at a high level.

It is preferable that the distribution density of the raised portion of the anti-blocking layer is 100 pieces / mm ² or more and 1200 pieces / mm ^{2 or less.} As a result, high handleability and excellent low reflection characteristics can be exhibited.

The haze of the anti-blocking layer is preferably 0.7% or more and 3% or less. With this configuration, the haze of the entire transparent conductive film can be reduced, and the optical characteristics of the display module can be improved.

The transparent conductive layer is provided on the surface side of the anti-blocking layer opposite to the transparent film base material side, and at least one coating layer is formed between the transparent conductive layer and the anti-blocking layer. It may have been done. Further, the transparent conductive layer is provided on the surface side of the transparent film base material opposite to the anti-blocking layer side, and at least one layer is coated between the transparent conductive layer and the transparent film base material. Layers may be formed. Regardless of the configuration, further functions based on the coating layer can be suitably imparted.

In one embodiment, the transparent conductive film is arranged between the polarizing plate and the display element. Since the transparent conductive film reduces the influence of circularly polarized light on the antireflection function, it can be easily incorporated into a high-performance display module.

The present invention also includes a polarizing plate and
Display element and
The present invention relates to a display device with a touch function including the transparent conductive film arranged between the polarizing plate and the display element.

The display device with a touch function provided with the transparent conductive film can exhibit excellent low reflection characteristics as well as handleability during processing.

A fixed layer is provided between the anti-blocking layer forming surface side of the transparent conductive film and the polarizing plate or the display element, and the refractive index na of the fixed layer, the refractive index np of the particles, and the binder are provided. The absolute value of the difference between the maximum value and the minimum value of the refractive index nb of the resin is preferably 0.14 or less. With such a configuration, the low reflection characteristics of the entire display module can be enhanced, and further high functionality can be achieved.

In the display device with a touch function, the fixed layer may be an adhesive layer or an adhesive layer. These configurations facilitate optical design.

It is a schematic sectional view of the transparent conductive film which concerns on one Embodiment of this invention. It is a schematic sectional view of the display device with a touch function which concerns on one Embodiment of this invention. It is a reflection spectrum measured in Example 1. It is a reflection spectrum measured in Example 2. It is a reflection spectrum measured in Example 3. It is a reflection spectrum measured in Example 4. It is a reflection spectrum measured in Comparative Example 2. It is a reflection spectrum measured in Comparative Example 3. It is a reflection spectrum measured in Comparative Example 4. It is a reflection spectrum measured in Comparative Example 5. It is a reflection spectrum measured in Comparative Example 6. It is a reflection spectrum measured in Comparative Example 7. It is a reflection spectrum measured in Comparative Example 8.

A transparent conductive film according to an embodiment of the present invention and a display device with a touch function provided with the transparent conductive film will be described below with reference to the drawings. However, in a part or all of the figure, a part unnecessary for explanation is omitted, and there is a part shown by enlargement or reduction for facilitation of explanation. The terms indicating the positional relationship such as top and bottom are used merely for the sake of facilitation of explanation, and unless otherwise specified, there is no intention of limiting the configuration of the present invention.

<Transparent conductive film>
FIG. 1 is a schematic cross-sectional view of a transparent conductive film according to an embodiment of the present invention. In the transparent conductive film 10, the transparent conductive layer 5 is formed on the first main surface (upper surface of the transparent film base material 1 in FIG. 1), which is one main surface of the transparent film base material 1. An anti-blocking layer 2 containing particles P is formed on the second main surface (lower surface of the transparent film base material 1 in FIG. 1), which is the other main surface of the transparent film base material 1. Further, between the transparent film base material 1 and the transparent conductive layer 5, a hard coat layer 3 and a refractive index adjusting layer 4 are formed in this order from the side of the transparent film base material 1.

(Transparent film base material)
As the transparent film base material 1, various plastic films having a front phase difference of 200 nm or less and having transparency are used. For example, as the material thereof, a polycycloolefin resin such as a polyester resin, an acetate resin, a polyether sulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, or a polynorbornen resin, (meth). ) Acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyallylate resin, polyphenylene sulfide resin and the like can be mentioned. Of these, polycycloolefin-based resins, polyester-based resins, polycarbonate-based resins, and polyolefin-based resins are particularly preferable.

The polycycloolefin-based resin film formed of the polycycloolefin-based resin has properties such as high transparency, low phase difference, and low water absorption. By adopting the polycycloolefin resin film, it is possible to control the optical characteristics of the transparent conductive film 10.

The polycycloolefin-based resin that forms the polycycloolefin-based resin film is not particularly limited as long as it is a resin having a monomer unit composed of a cyclic olefin (cycloolefin). The polycycloolefin resin used for the polycycloolefin resin film may be either a cycloolefin polymer (COP) or a cycloolefin copolymer (COC). The cycloolefin copolymer refers to a non-crystalline cyclic olefin resin which is a copolymer of a cyclic olefin and an olefin such as ethylene.

As the cyclic olefin, a polycyclic cyclic olefin and a monocyclic cyclic olefin exist. Examples of such polycyclic olefins include norbornene, methylnorbornene, dimethylnorbornene, ethylnorbornene, etilidennorbornene, butylnorbornene, dicyclopentadiene, dihydrodicyclopentadiene, methyldicyclopentadiene, dimethyldicyclopentadiene, and tetracyclododecene. , Methyltetracyclododecene, dimethylcyclotetradodecene, tricyclopentadiene, tetracyclopentadiene and the like. Examples of the monocyclic olefin include cyclobutene, cyclopentene, cyclooctene, cyclooctadiene, cyclooctatriene, cyclododecatriene and the like.

The optical film made of the above polycycloolefin resin is also available as a commercial product. For example, Topas manufactured by Ticonna, Arton manufactured by JSR, ZEONOR, ZEONEX manufactured by Zeon Corporation, Appel manufactured by Mitsui Chemicals, etc. Can be mentioned.

The thickness of the transparent film substrate 1 is preferably in the range of 2 to 200 μm, more preferably in the range of 20 to 180 μm. If the thickness of the transparent film base material 1 is less than 2 μm, the mechanical strength of the transparent film base material 1 is insufficient, and it becomes difficult to roll the film base material into a roll to continuously form the transparent conductive layer 5. In some cases. On the other hand, if the thickness exceeds 200 μm, the scratch resistance of the transparent conductive layer 5 and the striking characteristics for a touch panel may not be improved.

The surface of the transparent film substrate 1 is preliminarily subjected to etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical formation, oxidation, and undercoating to form a hard coat layer on the film substrate. Or, the adhesion to the transparent conductive layer or the like may be improved. Further, before forming the hard coat layer or the transparent conductive layer, the surface of the film substrate may be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like, if necessary.

A λ / 4 retardation plate can be used as the transparent film substrate 1. With such a configuration, it is not necessary to separately provide a λ / 4 retardation plate together with the transparent conductive film 10, and it is possible to improve the display display characteristics and reduce the thickness of the device.

The λ / 4 retardation plate is not particularly limited as long as it mutually converts circularly polarized light and linearly polarized light. In the present specification and claims, "circularly polarized light" may include not only completely circularly polarized light but also elliptically polarized light which is close to perfect circularly polarized light, that is, the ellipticity is close to 1. Such elliptically polarized light is obtained, for example, when linearly polarized light passes through a retardation plate having a slow axis at an angle of 45 ° with respect to the vibration direction and a frontal retardation of 100 to 180 nm. It contains elliptically polarized light. In the specification of the present application and claims, unless otherwise specified, the polarization state, retardation, etc. are all at a wavelength of 550 nm when the screen is observed from the front direction, that is, from the normal direction of the screen. Refers to the polarization state, lettering, etc. Further, circularly polarized light and elliptically polarized light may be clockwise or counterclockwise. Further, the polarized state does not necessarily have to be completely polarized, and may be partially polarized including a partially unpolarized state.

The front phase difference of the λ / 4 retardation plate may be 200 nm or less, but is preferably 100 to 180 nm, more preferably 110 to 170 nm, and particularly preferably 120 to 160 nm.

As the polymer constituting the λ / 4 retardation plate, for example, a cellulose derivative having a predetermined degree of substitution disclosed in JP-A-2000-137116, etc., and a copolymer disclosed in WO00 / 26705, International Publication Pamphlet, etc. Polycarbonate, polyvinyl acetal-based polymers disclosed in JP-A-2006-171235, JP-A-2006-89696, and the like are preferably used. Further, a retardation adjusting agent as disclosed in Japanese Patent Application Laid-Open No. 2004-325523 can also be used.

Further, as the λ / 4 retardation plate, a laminated retardation plate in which two or more films are laminated may be used. For example, as disclosed in JP-A-5-27118, JP-A-5-27119, etc., laminated retardation plates laminated so that the angles formed by the slow axes are orthogonal to each other, and JP-A-5. As disclosed in JP-A-100114, JP-A-10-68816, JP-A-11-149015, JP-A-2006-1717113, etc., the slow-phase axes should form an angle that is neither parallel nor vertical. A laminated retardation plate or the like laminated on the above can be preferably used.

In the present embodiment, the λ / 4 retardation plate not only converts circularly polarized light and linearly polarized light at a wavelength of 550 nm, but also has a wide band of visible light, that is, a wavelength of 400 to 800 nm, particularly 450 to 750 nm. In the range, it is preferable to convert circularly polarized light and linearly polarized light to each other.

The λ / 4 retardation plate can be formed by an appropriate method such as a casting method such as a casting method or an extrusion method. The obtained film may be stretched. The thickness of the λ / 4 retardation plate is generally 2 to 200 μm, preferably 20 to 180 μm, and more preferably 40 to 200 μm.

(Anti-blocking layer)
The anti-blocking layer 2 is a cured product layer of a resin composition containing a binder resin and particles, and has a flat portion 2a and a raised portion 2b on the surface. The raised portion 2b is formed due to the particles P contained in the anti-blocking layer 2. In the transparent conductive film 10 of the present embodiment, since the mode particle diameter of the particles P is larger than that of the flat portion 2a of the anti-blocking layer 2, it is excellent in slipperiness and blocking resistance, and exhibits good handling properties. be able to. Further, by providing the flat portion 2a, the haze of the anti-blocking layer 2 can be reduced and the transparency can be further improved.

In the present embodiment, the refractive index np of the particles P and the refractive index nb of the binder resin satisfy the following relationship.
| Np-nb | <0.14

Since the refractive index np of the particles P forming the raised portion 2b that easily causes light scattering and depolarization and the refractive index nb of the binder resin forming the matrix of the anti-blocking layer 2 satisfy the above relationship, the transparent conductive film The influence on the optical characteristics at the time of incorporation into the display module can be suitably reduced. It is more preferable that the refractive index np of the particles P and the refractive index nb of the binder resin satisfy the following relationship.
| Np-nb | <0.10

The maximum roughness Rz of the surface of the anti-blocking layer 2 on the side opposite to the transparent film substrate 1 side is preferably 0.3 μm or more and 2.5 μm or less, and preferably 0.3 μm or more and 1.5 μm or less. More preferred. As a result, handleability and low reflection characteristics can be exhibited at a high level.

Preferably the distribution density of the raised portion 2b of the anti-blocking layer 2 is 100 / mm ² or more 1200 / mm ² or less, more preferably 100 pieces / mm ² or more 1000 / mm ² or less. As a result, high handleability and excellent low reflection characteristics can be exhibited.

The haze of the anti-blocking layer 2 is preferably 0.7% or more and 3% or less, and more preferably 0.7% or more and 2.5% or less. With this configuration, the haze of the entire transparent conductive film can be reduced, and the optical characteristics of the display module can be improved.

The thickness of the flat portion 2a of the anti-blocking layer 2 is not particularly limited, but is preferably 200 nm or more and 30 μm or less, more preferably 500 nm or more and 10 μm or less, and further preferably 800 nm or more and 5 μm or less. If the thickness of the flat portion of the anti-blocking layer is excessively small, the precipitation of low molecular weight components such as oligomers from the transparent film substrate cannot be suppressed, and the visibility of the transparent conductive film and the touch panel using the same cannot be suppressed. Tends to get worse. On the other hand, if the thickness of the flat portion of the anti-blocking layer is excessively large, the transparent conductive film tends to curl with the anti-blocking layer forming surface as the inside due to heating during crystallization of the transparent conductive layer or assembly of the touch panel. .. Therefore, when the thickness of the flat portion of the anti-blocking layer is large, it tends to be inferior in the handleability of the film due to problems other than blocking resistance and slipperiness. In the present specification, the thickness of the flat portion of the anti-blocking layer refers to the average thickness of the flat portion of the anti-blocking layer.

The most frequent particle diameter of the particles can be appropriately set in consideration of the relationship between the size of the raised portion of the outermost surface layer and the thickness of the flat portion 2a of the anti-blocking layer 2, and is not particularly limited. From the viewpoint of sufficiently imparting blocking resistance to the transparent conductive film and sufficiently suppressing light scattering, the mode particle diameter of the particles is preferably 500 nm or more and 30 μm or less, and 800 nm or more and 20 μm or less. It is more preferable that it is 1 μm or more and 10 μm or less. In the present specification, the "most frequent particle size" means a particle size indicating a maximum value of particle distribution, and a flow type particle image analyzer (manufactured by Sysmex, product name "FPIA-3000S") is used. , Obtained by measuring under predetermined conditions (Sheath solution: ethyl acetate, measurement mode: HPF measurement, measurement method: total count). As the measurement sample, the particles are diluted with ethyl acetate to 1.0% by weight and uniformly dispersed using an ultrasonic cleaner.

The height of the raised portion 2b is set in consideration of the required slipperiness and the like. The height of the raised portion 2b, that is, the portion of the anti-blocking layer 2 protruding upward from the flat portion 2a can be controlled by the thickness of the flat portion 2a of the anti-blocking layer 2, the mode of the particles P, and the like. The height of the raised portion 2b is preferably 100 nm or more and 3 μm or less, more preferably 200 nm or more and 2 μm or less, and further preferably 300 nm or more and 1.5 μm or less. By setting the height of the raised portion 2b in the above range, the blocking resistance of the transparent conductive film 10 can be satisfied, and at the same time, light scattering and depolarization can be sufficiently suppressed.

The particles may be either polydisperse particles or monodisperse particles, but monodisperse particles are preferable in consideration of the ease of providing raised portions and the light scattering prevention property. In the case of monodisperse particles, the particle size of the particles and the mode particle size can be regarded as substantially the same.

The content of the particles in the anti-blocking layer is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 1 part by weight, based on 100 parts by weight of the solid content of the resin composition. It is more preferably 0.05 to 0.5 parts by weight. When the content of particles in the anti-blocking layer is small, it tends to be difficult to form a ridge sufficient to impart blocking resistance and slipperiness to the surface of the anti-blocking layer. On the other hand, if the content of the particles is too large, the degree of light scattering and polarization elimination by the particles increases, and the optical characteristics such as low reflection characteristics when incorporated into the display module tend to deteriorate. Further, if the content of the particles is too large, streaks are generated when the anti-blocking layer is formed (when the solution is applied), the visibility is impaired, and the electrical characteristics of the transparent conductive layer become non-uniform. In some cases.

(Resin composition)
As the binder resin in the resin composition forming the anti-blocking layer 2, particles can be dispersed, and a transparent film having sufficient strength as a film after forming the anti-blocking layer can be used without particular limitation. Examples of the binder resin to be used include thermosetting resins, thermoplastic resins, ultraviolet curable resins, electron beam curable resins, and two-component mixed resins. Among these, the curing process by ultraviolet irradiation is easy. An ultraviolet curable resin that can efficiently form a film by various processing operations is suitable.

Examples of the ultraviolet curable resin include polyester type, acrylic type, urethane type, amide type, silicone type, epoxy type and the like, and include ultraviolet curable monomers, oligomers, polymers and the like. Examples of the ultraviolet curable resin preferably used include those having an ultraviolet polymerizable functional group, and among them, those containing an acrylic monomer or an oligomer component having two or more, particularly 3 to 6 of the functional groups. Further, the ultraviolet curable resin contains an ultraviolet polymerization initiator.

In addition to the above materials, additives such as leveling agents, thixotropic agents, antistatic agents, plasticizers, surfactants, antioxidants, curing catalysts, and ultraviolet absorbers can be used in the resin composition. The use of thixotropic agents is advantageous for the formation of protruding particles on the surface of fine irregularities. Examples of the thixotropic agent include silica and mica having a thickness of 0.1 μm or less. The content of these additives is usually preferably about 15 parts by weight or less, preferably 0.01 to 15 parts by weight, based on 100 parts by weight of the ultraviolet curable resin.

The refractive index nb of the binder resin is appropriately set in consideration of the refractive index of the particles P, the optical characteristics required for the anti-blocking layer 2, and the like. The refractive index nb is preferably 1.40 or more and 1.80 or less, and more preferably 1.45 or more and 1.75 or less.

(particle)
As the particles P contained in the anti-blocking layer 2, transparent substances such as various metal oxides, glass, and plastic can be used without particular limitation. For example, crosslinked or uncrosslinked particles made of inorganic particles such as silica, alumina, titania, zirconia, calcium oxide, polymethylmethacrylate, polystyrene, polyurethane, acrylic resin, acrylic-styrene copolymer, benzoguanamine, melamine, polycarbonate and the like. Examples thereof include crosslinked organic particles and silicone particles. As the particles, one kind or two or more kinds can be appropriately selected and used, but organic particles are preferable. As the organic particles, an acrylic resin is preferable from the viewpoint of refractive index.

The refractive index np of the particles P is appropriately set in consideration of the refractive index of the binder resin, the optical characteristics required for the anti-blocking layer 2, and the like. The refractive index np is preferably 1.40 or more and 1.80 or less, and more preferably 1.45 or more and 1.75 or less.

(Coating composition)
In order to form the anti-blocking layer, it is preferable to use a coating composition containing the above resin composition and a solvent.

The coating composition is prepared by mixing a solvent with a resin composition containing the above-mentioned binder resin and particles. The solvent in the coating composition is not particularly limited, and is appropriately selected in consideration of the resin to be used, the material of the portion to be the base of coating, the coating method of the composition, and the like. Specific examples of the solvent include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone and cyclohexanone; diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether and ethylene glycol. Ether solvents such as diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, phenetol; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, ethylene glycol diacetate; dimethylformamide, diethylformamide, N -Amid-based solvents such as methylpyrrolidone; cellosolve-based solvents such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; alcohol-based solvents such as methanol, ethanol and propanol; halogen-based solvents such as dichloromethane and chloroform; and the like. These solvents may be used alone or in combination of two or more. Of these solvents, ester solvents, ether solvents, alcohol solvents and ketone solvents are preferably used.

The solid content concentration of the coating composition is preferably 1% by weight to 70% by weight, more preferably 2% by weight to 50% by weight, and most preferably 5% by weight to 40% by weight. If the solid content concentration is too low, the variation in the raised portion on the surface of the anti-blocking layer becomes large in the drying step after coating, and the haze of the portion where the raised portion on the surface of the anti-blocking layer becomes large may increase. On the other hand, if the solid content concentration becomes too high, the contained components tend to aggregate, and as a result, the aggregated portion may become apparent and the appearance of the transparent conductive film may be impaired.

(Applying, drying and curing)
The anti-blocking layer is formed by applying the above coating composition on the transparent film base material 1, drying the obtained coating liquid film, and curing the dried coating film. The coating composition is applied onto the transparent film base material 1 on one side of the base material in the case of the present embodiment as shown in FIG. The coating composition may be applied directly on the transparent film substrate 1, or may be applied on a coating layer or the like formed on the transparent film substrate 1.

The coating method of the coating composition can be selected in a timely manner according to the situation of the coating composition and the coating process, for example, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, and a gravure. It can be applied by a coating method, a die coating method, an extrusion coating method, or the like.

The drying conditions of the coating liquid film can be appropriately set according to the composition, thickness and the like of the coating composition. For example, the coating liquid film is dried by heating at 40 to 180 ° C. for 5 to 300 seconds in a known heat dryer. be able to.

Finally, the anti-blocking layer can be formed by curing the dried coating film. When the binder resin of the resin composition is ultraviolet curable, it can be cured by irradiating the binder resin with ultraviolet rays using a light source that emits ultraviolet rays having a wavelength as required. As ultraviolet rays to be irradiated, for example, the exposure amount 150 mJ / cm ² or more ultraviolet can be preferably used ultraviolet ^{200mJ / cm 2 ~1000mJ / cm 2} . The wavelength of the ultraviolet rays is not particularly limited, but for example, ultraviolet rays having a wavelength of 380 nm or less can be used. It should be noted that heating may be performed during the ultraviolet curing treatment.

(Transparent conductive layer)
The constituent material of the transparent conductive layer 5 is not particularly limited, and is selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten at least. A metal oxide of one type of metal is preferably used. The metal oxide may further contain the metal atoms shown in the above group, if necessary. For example, indium oxide (ITO) containing tin oxide, tin oxide (ATO) containing antimony, and the like are preferably used.

The thickness of the transparent conductive layer 5 is not particularly limited, but in ^{order to form a continuous coating having a surface resistance of 1 × 10 3} Ω / □ or less and having good conductivity, the thickness is preferably 10 nm or more. If the film thickness becomes too thick, the transparency will decrease, so the film thickness is preferably 15 to 50 nm, more preferably 20 to 45 nm. If the thickness of the transparent conductive layer 5 is less than 15 nm, the electrical resistance of the film surface becomes high and it becomes difficult to form a continuous film. Further, if the thickness of the transparent conductive layer 5 exceeds 50 nm, the transparency may decrease.

The method for forming the transparent conductive layer 5 is not particularly limited, and a conventionally known method can be adopted. Specifically, for example, a dry process such as a vacuum vapor deposition method, a sputtering method, or an ion plating method can be exemplified. Further, an appropriate method can be adopted depending on the required film thickness. Unlike FIG. 1, when the transparent conductive layer 5 is formed on the anti-blocking layer 2, if the transparent conductive layer 5 is formed by a dry process such as a sputtering method, the surface of the transparent conductive layer 5 is below the transparent conductive layer 5. The shape of the flat portion and the raised portion on the surface of the anti-blocking layer 2 which is the stratum is almost maintained. Therefore, even when the transparent conductive layer 5 is formed on the anti-blocking layer 2, it is possible to suitably impart blocking resistance and slipperiness to the surface of the transparent conductive layer 5.

The transparent conductive layer 5 can be crystallized by subjecting it to a heat annealing treatment (for example, in an atmospheric atmosphere at 80 to 150 ° C. for about 30 to 90 minutes), if necessary. By crystallizing the transparent conductive layer, in addition to lowering the resistance of the transparent conductive layer, transparency and durability are improved. By setting the thickness of the anti-blocking layer 2a in the transparent conductive film 10 within the above range, the generation of curl is suppressed even during the heat annealing treatment, and the handling property is excellent.

Further, the transparent conductive layer 5 may be patterned by etching or the like. For example, in a transparent conductive film used for a capacitance type touch panel or a matrix type resistance film type touch panel, it is preferable that the transparent conductive layer 5 is patterned in a stripe shape. When the transparent conductive layer 5 is patterned by etching, if the transparent conductive layer 5 is crystallized first, it may be difficult to pattern the transparent conductive layer 5 by etching. Therefore, it is preferable that the annealing treatment of the transparent conductive layer 5 is performed after the transparent conductive layer 5 is patterned.

(Coating layer)
In the transparent conductive film 10 of the present embodiment, the hard coat layer 3 and the refractive index adjusting layer 4 are sequentially coated layers between the transparent film base material 1 and the transparent conductive layer 5 from the side of the transparent film base material 1. It is formed. By providing such a coating layer, it is possible to further enhance the functionality of the transparent conductive film.

(Hard coat layer)
The hard coat layer 3 is formed for the purpose of imparting strength to the transparent film base material 1 to prevent cracking of the transparent film base material 1 and to improve handleability. The details of the hard coat layer 3 are the same as those of the anti-blocking layer 2 except that they do not contain particles, and thus the description thereof will be omitted here. The thickness of the hard coat layer 3 is the same as the thickness of the flat portion 2a of the anti-blocking layer 2.

(Refractive index adjustment layer)
The refractive index adjusting layer 4 is provided for the purpose of controlling the adhesion and reflection characteristics of the transparent conductive layer 5. The refractive index adjusting layer may be one layer or two or more layers. The refractive index adjusting layer is formed of an inorganic substance, an organic substance, or a mixture of an inorganic substance and an organic substance. Materials for forming the refractive index adjusting layer include NaF, Na ₃ AlF ₆ , LiF, MgF ₂ , CaF _2, SiO ₂ , LaF ₃ , CeF ₃ , Al ₂ O ₃ , _{TIO 2} , Ta ₂ O ₅ , and ZrO _2. , ZnO, ZnS, SiO _x (x is 1.5 or more and less than 2), and organic substances such as acrylic resin, urethane resin, melamine resin, alkyd resin, and siloxane polymer. In particular, as the organic substance, it is preferable to use a thermosetting resin composed of a mixture of a melamine resin, an alkyd resin and an organic silane condensate. The refractive index adjusting layer can be formed by a coating method such as a gravure coating method or a bar coating method, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like using the above materials.

The thickness of the refractive index adjusting layer 4 is preferably 10 nm to 200 nm, more preferably 20 nm to 150 nm, and even more preferably 20 nm to 130 nm. If the thickness of the refractive index adjusting layer is excessively small, it is difficult to form a continuous film. Further, if the thickness of the refractive index adjusting layer is excessively large, the transparency of the transparent conductive film tends to decrease, and the refractive index adjusting layer tends to be easily cracked. Further, when the anti-blocking layer is formed on the first main surface (upper surface in FIG. 1) side of the transparent film base material 1, if the refractive index adjusting layer is formed with the thickness of the nano-order level as described above, The surface of the refractive index adjusting layer on the transparent conductive layer 5 side substantially maintains the raised shape of the surface of the anti-blocking layer 2 which is the underlying layer. Since the raised shape is maintained on the surface of the transparent conductive layer 5 and the raised portion 32 is formed, the transparent conductive film having blocking resistance and slipperiness can be obtained.

The refractive index adjusting layer may have nanoparticles having an average particle size of 1 nm to 500 nm. The content of the nanoparticles in the refractive index adjusting layer is preferably 0.1% by weight to 90% by weight. The average particle size of the nanoparticles used in the refractive index adjusting layer is preferably in the range of 1 nm to 500 nm, and more preferably 5 nm to 300 nm, as described above. Further, the content of the nanoparticles in the refractive index adjusting layer is more preferably 10% by weight to 80% by weight, further preferably 20% by weight to 70% by weight. By containing the nanoparticles in the refractive index adjusting layer, the refractive index of the refractive index adjusting layer itself can be easily adjusted.

Examples of the inorganic oxide forming the nanoparticles include fine particles such as silicon oxide (silica), hollow nanosilica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, and zirconium oxide. Among these, fine particles of silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, and zirconium oxide are preferable. These may be used alone or in combination of two or more.

The haze of the transparent conductive film is not particularly limited as long as the required transparency can be ensured, but is preferably 5% or less, more preferably 4% or less, still more preferably 3% or less.

The transparent conductive film 10 of the present embodiment can be a transparent conductive film wound body in which a long sheet is wound in a roll shape. For the winding body of the long sheet of the transparent conductive film, a roll-shaped winding body of the long sheet is used as the transparent film base material, and in addition to the above-mentioned anti-blocking layer and transparent conductive layer, a hard coat layer and a refractive index adjustment are used. Any additional layer such as a layer can be formed by forming by a roll-to-roll method. In forming such a wound body, a surface protective film (release film) provided with a weak adhesive layer may be attached to the surface of the transparent conductive film and then wound in a roll shape. Since the transparent conductive film of the embodiment has improved slipperiness and blocking resistance, it is possible to form a wound body of a long sheet of the transparent conductive film without using a surface protective film. That is, since the slipperiness and blocking resistance are improved, the occurrence of scratches on the film surface during handling is suppressed and the film winding property is excellent, so that the surface protective film does not need to be attached to the surface. , It is easy to obtain a wound body made by winding a long sheet into a roll. As described above, since the transparent conductive film of the present embodiment can form a wound body of a long sheet without using a surface protective film, it is excellent in workability when used for subsequent formation of a touch panel or the like. Further, by eliminating the need for a protective film which is a process member, it can contribute to cost reduction and waste reduction.

The transparent conductive film 10 can be suitably applied to a touch panel such as a capacitance type or a resistance film type.

When forming the touch panel, another base material such as glass or a polymer film can be attached to one or both main surfaces of the transparent conductive film via a transparent adhesive layer. For example, a laminate may be formed in which a transparent substrate is bonded to the surface of the transparent conductive film on the side where the transparent conductive layer 5 is not formed via a transparent adhesive layer. The transparent substrate may consist of one substrate film, or may be a laminate of two or more substrate films (for example, one laminated via a transparent pressure-sensitive adhesive layer). Further, a hard coat layer can be provided on the outer surface of the transparent substrate to be bonded to the transparent conductive film.

The pressure-sensitive adhesive layer used for bonding the transparent conductive film and the base material can be used without particular limitation as long as it has transparency. Specifically, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy-based, fluoro-based, natural rubbers, synthetic rubbers and other rubber-based rubbers, etc. A polymer based on the above polymer can be appropriately selected and used. In particular, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit adhesive properties such as appropriate wettability, cohesiveness and adhesiveness, and are also excellent in weather resistance and heat resistance.

When the transparent conductive film according to the present invention is used for forming a touch panel, the handling property at the time of forming the touch panel is excellent. Therefore, it is possible to manufacture a touch panel having excellent transparency and visibility with high productivity.

The transparent conductive film of the present embodiment is suitable as, for example, antistatic, electromagnetic wave blocking, liquid crystal dimming glass, transparent heater, etc. of transparent electrodes and transparent members of various display elements such as liquid crystal display elements, solid-state image pickup elements, and organic EL elements. Can be used for.

<Display device with touch function>
FIG. 2 is a schematic cross-sectional view of a display device with a touch function according to an embodiment of the present invention. The display device 100 with a touch function includes a polarizing plate 20, a display element 30, and a transparent conductive film 10 arranged between the polarizing plate 20 and the display element 30. Fixed layers 13a and 13b are provided between the polarizing plate 20 and the transparent conductive film 10 and between the transparent conductive film 10 and the display element 30, respectively, and each element is fixed to each other. Since the transparent conductive film 10 has already been described above, the polarizing plate 20 and the display element 30 will be described below.

(Polarizer)
The polarizing plate 20 of the present embodiment has a structure in which protective films 22a and 22b are bonded to both sides of a polarizing element 21 via an adhesive layer (not shown).
(Polarizer)
As the polarizing element 21, among orthogonal linearly polarized light, one that transmits polarized light having a vibration plane parallel to the transmission axis as it is and selectively absorbs polarized light having a vibration plane parallel to the absorption axis can be used. .. As the polarizing element 21, it is preferable to use a polymer film in which iodine is adsorbed and oriented. As the polymer film, for example, various films can be used without particular limitation. For example, a polyvinyl alcohol-based film, a polyethylene terephthalate-based film, an ethylene / vinyl acetate copolymer-based film, a partially saponified film thereof, a hydrophilic polymer film such as a cellulose-based film, a dehydrated product of polyvinyl alcohol, or polyvinyl chloride is used. Examples thereof include a polyene-based oriented film such as a vinyl dehydrogenated product. Among these, it is preferable to use a polyvinyl alcohol-based film having excellent dyeability with iodine.

When a polyvinyl alcohol-based film is used as the polymer film, the polyvinyl alcohol-based film can be produced by any method such as a casting method, a casting method, or an extrusion method in which a stock solution dissolved in water or an organic solvent is cast and formed. The filmed one can be used as appropriate. The polymer film (unstretched film) is subjected to at least uniaxial stretching treatment and iodine dyeing treatment according to a conventional method. Further, boric acid treatment and cleaning treatment can be performed. Further, the polymer film (stretched film) subjected to the above treatment is dried according to a conventional method to become a polarizing element.

The thickness of the polarizing element 21 is not particularly limited, and is preferably 15 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 10 μm, and particularly preferably 3 μm to 8 μm.

(Polarizer protective film)
The polarizing element protective films 22a and 22b have transparency to light, and as a constituent material thereof, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is used. Be done. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, and cyclic resins. Examples thereof include a polyolefin resin (norbornen-based resin), a polyarylate resin, a polystyrene resin, a polyvinyl alcohol resin, and a mixture thereof.

When the polarizing element protective film is required to have optical isotropic properties, that is, an in-plane retardation of 10 nm or less, preferably 5 nm or less, more preferably 3 nm or less, a cellulosic resin is preferably used. It is also preferable to use a cyclic polyolefin resin as the polarizing element protective film having optical isotropic properties. Specific examples of the cyclic polyolefin-based resin are norbornene-based resins.

The thicknesses of the polarizing element protective films 22a and 22b can be appropriately set, but are generally about 1 to 500 μm in terms of strength, workability such as handling, and thin layerability. In particular, 1 to 300 μm is preferable, and 5 to 200 μm is more preferable. The protective film is particularly suitable when the thickness is 5 to 150 μm.

When the polarizing element protective films are provided on both sides of the polarizing element 21, the polarizing element protective films made of the same polymer material may be used on the front and back sides thereof, or the polarizing element protective films made of different polymer materials or the like may be used.

As the polarizing element protective film, a retardation plate having a retardation satisfying one or both of a frontal retardation of 40 nm or more and a thickness direction retardation of 80 nm or more can be used. The frontal phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retarder protective film is used as the retarder protective film, the retarder protective film also functions as the retarder protective film, so that the thickness can be reduced.

Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a film in which an alignment layer of a liquid crystal polymer is supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, and polyethersulfone. Polyphenylsulfone, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornen-based resin), or their binary, ternary various copolymers, and grafts. Examples include polymers and blends. These polymer materials become oriented substances (stretched films) by stretching or the like.

The retardation plate may have an appropriate phase difference according to the purpose of use, for example, for the purpose of compensating for coloring and viewing angle due to birefringence of various wave plates and liquid crystal layers, and may have two or more types. A phase difference plate may be laminated to control optical characteristics such as a phase difference.

(Adhesive layer)
The adhesive layer used for bonding the polarizing element 21 and the polarizing element protective films 22a and 22b is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt-based, and radical-curing type can be used. Although used, water-based adhesives or radically curable adhesives are preferred.

The water-based adhesive forming the adhesive layer is not particularly limited, and examples thereof include vinyl polymer-based, gelatin-based, vinyl-based latex-based, polyurethane-based, isocyanate-based, polyester-based, and epoxy-based adhesives.

The adhesive layer is formed so that the thickness of the adhesive after drying is 0.01 to 20 μm, preferably 0.02 to 10 μm, and more preferably 0.5 to 5 μm. preferable.

(Display element)
As the display element 30, for example, a display element such as a liquid crystal display device, a plasma display panel, an organic electroluminescence display, or a cathode tube display device can be adopted. By arranging a λ / 4 retardation plate together with the polarizing plate 20 to convert between circularly polarized light and linearly polarized light, a reflective liquid crystal display device that easily causes specular reflection of external light and reflection of an electroluminescence display. It is suitably used as an optical element for the purpose of prevention.

The liquid crystal display device as the display element 30 includes a cell substrate 31, a polarizing plate 32b arranged on the visible side of the cell substrate 31 (upper side of the cell substrate 31 in FIG. 1), and a back side of the cell substrate 31 (FIG. 1). A polarizing plate 32a arranged on the lower side of the cell substrate 31) is provided. The polarizing plates 32a and 32b are attached to the cell substrate 31 via an adhesive layer (not shown), respectively.

Liquid crystal display devices generally include cell substrates and polarizing plates, as well as retardation films, viewing angle magnifying films, diffusers, antiglare layers, antireflection films, protective films, prism arrays, lens array sheets, reflectors, and semi-transmissive reflections. It can be formed by appropriately assembling a plate, an optical layer such as a brightness improving film, and, if necessary, components such as a lighting system, and incorporating a drive circuit.

Examples of the cell substrate 31 include twisted nematic (TN) mode, super twisted nematic (STN) mode, horizontal orientation (ECB) mode, vertical alignment (VA) mode, inplane switching (IPS) mode, and fringe field switching (FFS). ) Mode, bend nematic (OCB) mode, hybrid orientation (HAN) mode, ferroelectric liquid crystal display (SSFLC) mode, antiferroelectric liquid crystal display (AFLC) mode cell substrate and the like.

In the case of an organic electroluminescence display, a display device configured by appropriately combining a light emitting element, an electrode, a reflector, a sealing base material, and the like is used.

(Fixed layer)
The fixing layers 13a and 13b are members for fixing the polarizing plate 20, the transparent conductive film 10, the display element 30, other functional films, and the like to each other. As the fixed layers 13a and 13b, an adhesive layer or an adhesive layer is preferable.

As the material for forming the pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive having a polymer such as an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as a base polymer is appropriately selected and used. be able to. In particular, those having excellent optical transparency, appropriate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance, such as acrylic pressure-sensitive adhesives, can be preferably used.

As the material for forming the adhesive layer, for example, an adhesive composed of an acrylic polymer or a vinyl alcohol polymer, or a water-soluble cross-linking agent for a vinyl alcohol polymer such as boric acid, borosand, glutaaldehyde, melamine, and oxalic acid. It can be done via at least an adhesive or the like. As a result, it is difficult to peel off due to the influence of humidity and heat, and the light transmittance and the degree of polarization can be made excellent.

The absolute value of the difference between the maximum and minimum values of the refractive index na of the fixed layer 13a in contact with the anti-blocking layer 2, the refractive index np of the particles P, and the refractive index nb of the binder resin is 0.14 or less. It is preferably 0.1 or less, and more preferably 0.1 or less. With such a configuration, the low reflection characteristics of the entire display module can be enhanced, and further high functionality can be achieved.

(Λ / 4 phase difference plate)
In the display device 100 with a touch function of the present embodiment, a λ / 4 retardation plate can be used as the transparent film base material 1, or a λ / 4 retardation plate is used between the polarizing plate 20 and the transparent conductive film 10. Can also be placed. A circular polarizing plate can be configured by combining the polarizing element 21 and the λ / 4 retardation plate. By providing a circularly polarizing plate on the visual side of the display element, it is possible to prevent external light reflected by the reflector or metal electrode of the display element from being emitted to the visual side again (specular reflection), and the reflectance is reduced. Can be planned. In this case, it is preferable that the angle formed by the slow axis direction of the λ / 4 retardation plate and the absorption axis direction of the polarizing element 21 is 45 ° ± 5 °, which is 45 ° ± 3 °. It is more preferable to arrange them so as to be 45 ° ± 1 °.

<Other embodiments>
In the embodiment shown in FIG. 1, the transparent conductive layer 5 is provided only on one first main surface (upper surface) side of the transparent film base material 1, but is not limited to this, and the other second main surface is not limited to this. It may also be provided on the (bottom surface) side. In this case, when the anti-blocking layer 2 is formed as the base layer as shown in FIG. 1, the transparent portion provided on the second main surface side is caused by the flat portion and the raised portion of the anti-blocking layer 2. A flat portion and a raised portion are also formed on the surface of the conductive layer. Similarly, the anti-blocking layer 2 is provided only on the second main surface (lower surface) side of one of the transparent film base materials 1, but is not limited to this, and together with the anti-blocking layer on the second main surface side, the anti-blocking layer 2 is provided. Alternatively, instead of the anti-blocking layer 2 on the second main surface side, it may be provided on the other second main surface (lower surface) side. The hard coat layer 3 and the refractive index adjusting layer 4 are also provided on the second main surface side of the transparent film base material 1 together with the first main surface side of the transparent film base material 1 or instead of the first main surface side. May be.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the examples, "parts" means "parts by weight" unless otherwise specified.

<Example 1>
(1. Preparation of transparent conductive film)
Multiple monodisperse particles with an average particle diameter of 1.8 μm (manufactured by Soken Kagaku Co., Ltd., trade name “MX180-TAN”, refractive index 1.495) and binder resin (manufactured by DIC Co., Ltd., “UNIDIC”, refractive index 1.51). ), And a coating composition using ethyl acetate as a solvent was prepared. The number of particles added was 0.16 with respect to 100 with the binder resin. Next, the thickness of the flat portion after drying the coating composition on one side of a long film base material (manufactured by Nippon Zeon Corporation, trade name "ZEONOR") having a thickness of 40 μm using a gravure coater is 1.0 μm. The coating film was dried by heating at 80 ° C. Then, the anti-blocking layer was formed by irradiating with an ultraviolet ray having an integrated light amount of 250 mJ / cm ^{2 with a high-pressure mercury lamp.}

Subsequently, a coating composition prepared by diluting a binder resin (manufactured by DIC Corporation, “UNIDIC”, refractive index 1.51) with ethyl acetate was prepared. The coating composition is applied to the surface of the long film substrate opposite to the anti-blocking layer using a gravure coater so that the thickness of the flat portion after drying is 1.0 μm, and the mixture is heated at 80 ° C. The coating film was dried by. Then, a hard coat layer was formed by irradiating with an ultraviolet ray having an integrated light intensity of 250 mJ / cm ^{2 with a high-pressure mercury lamp.}

Next, on the surface of the hard coat layer, a refractive index adjuster (manufactured by JSR, trade name "Opstar Z7412": an organic-inorganic composite material having a refractive index of 1.62 containing zirconia oxide particles having a median diameter of 40 nm as an inorganic component). Was applied using a gravure coater, and the coating film was dried by heating at 60 ° C. Then, a high-pressure mercury lamp was used to irradiate ultraviolet rays with an integrated light intensity of 250 mJ / cm ² to perform a curing treatment to form a refractive index adjusting layer having a thickness of 115 nm and a refractive index of 1.62.

Next, the long film substrate on which each of the above layers was formed was put into a take-up sputtering apparatus, and an indium tin oxide oxide layer (argon gas 98%) having a thickness of 25 nm was placed on the surface of the refractive index adjusting layer as a transparent conductive layer. In an atmosphere of 0.4 Pa composed of 2% oxygen and 97% by weight of indium oxide-by a sputtering film forming method using a sintered body composed of 3% by weight of tin oxide) was laminated. As a result, the transparent conductive film A having the form shown in FIG. 1 was obtained.

(2. Preparation of polarizing plate)
A long roll of a polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") having a thickness of 30 μm is uniaxially stretched in the longitudinal direction so as to be 5.9 times in the longitudinal direction by a roll stretching machine. At the same time, swelling, dyeing, cross-linking, and washing treatment were performed, and finally, a drying treatment was performed to prepare a polarizing element having a thickness of 12 μm.

Specifically, the swelling treatment was carried out by stretching 2.2 times while treating with pure water at 20 ° C. Next, the dyeing treatment was performed in an aqueous solution at 30 ° C. (weight ratio of iodine to potassium iodide 1: 7) in which the iodine concentration was adjusted so that the simple substance transmittance of the obtained polarizing element was 45.0%. However, it was stretched 1.4 times. Further, the cross-linking treatment adopted a two-step cross-linking treatment, and the first-step cross-linking treatment was carried out 1.2 times while being treated with an aqueous solution in which boric acid and potassium iodide were dissolved at 40 ° C. The boric acid content of the aqueous solution of the first-step crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. The second-step cross-linking treatment was carried out by stretching 1.6 times while treating with an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C. The boric acid content of the aqueous solution of the second step cross-linking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. The washing treatment was carried out with an aqueous potassium iodide solution at 20 ° C. The potassium iodide content of the aqueous solution of the washing treatment was set to 2.6% by weight. Finally, the drying process was carried out at 70 ° C. for 5 minutes to obtain a stator.

An HC-TAC film (thickness 32 μm) having a hard coat (HC) layer formed by a hard coat treatment on one side of the TAC film via a polyvinyl alcohol-based adhesive is placed on one side of the polarizing element on the other side. A normal TAC film (thickness 25 μm) is bonded to the vinyl alcohol-based adhesive by a roll-to-roll method, and has a long-shaped structure having a stator protective film / a polarizing element / a polarizing element protective film. A polarizing plate was obtained.

(3. Fabrication of λ / 4 retardation plate)
445.1 parts by weight of isosorbide (manufactured by Rocket Frere, trade name: POLYSORB), 906.2 parts by weight of 9,9- (4- (2-hydroxyethoxy) phenyl) fluorene (manufactured by Osaka Gas Chemical Co., Ltd.) , 15.4 parts by weight of polyethylene glycol having a molecular weight of 1000, 1120.4 parts by weight of diphenyl carbonate (manufactured by Sanyo Kasei Kogyo Co., Ltd.), and 6.27 parts by weight of cesium carbonate (0.2% by weight aqueous solution) as a catalyst. As the first step of the reaction, the heat medium temperature of the reaction vessel was set to 150 ° C., and the raw materials were dissolved while stirring as necessary (about). 15 minutes). Next, the pressure inside the reaction vessel was changed from normal pressure to 13.3 kPa, and the heat medium temperature of the reaction vessel was raised to 190 ° C. in 1 hour, and the generated phenol was extracted from the reaction vessel. Polycarbonate was produced through this step.

After vacuum drying the produced polycarbonate at 80 ° C for 5 hours, a single-screw extruder (manufactured by Isuzu Kakoki Co., Ltd., screw diameter 25 mm, cylinder set temperature: 220 ° C, T-die (width 200 mm, set temperature: 220 ° C), chill roll (Set temperature: 120 to 130 ° C.)) and a film forming apparatus equipped with a winder were used to prepare a raw film having a thickness of 100 μm. This sample was stretched at a stretching speed of 720 mm / min (strain) so that _{R 1} (550) was 140 ± 10 nm while adjusting the stretching temperature at 127 to 177 ° C. using a batch type biaxial stretching device (manufactured by Toyo Seiki Co., Ltd.). A uniaxial stretching of 1 × 2.0 times was performed at a speed of 1200% / min) to obtain a λ / 4 retardation plate having a thickness of 50 μm.

(4. Preparation of adhesive)
70 parts by weight of isononyl acrylate, 25 parts by weight of butyl acrylate, 5 parts by acrylic acid, 0.1 part by weight of 2,2-azobisisobutyronitrile and 200 parts by weight of ethyl acetate, nitrogen introduction tube and cooling tube. After being put into the provided four-necked flask and sufficiently replaced with nitrogen, the polymerization reaction was carried out at 55 ° C. for 20 hours while stirring under a nitrogen stream to obtain an acrylic polymer having a weight average molecular weight of 1.25 million. A pressure-sensitive adhesive composition containing 0.4 parts by weight of dibenzoyl peroxide and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane with respect to 100 parts by weight of the solid content of the polymer solution was subjected to silicone peeling treatment at 38 μm. Is applied to the PET film of No. 1 so that the dry thickness of the pressure-sensitive adhesive layer is 25 μm, dried and crosslinked at 130 ° C. for 3 minutes, transferred to the HC-TAC surface of the above-mentioned polarizing plate, and adhered to an acrylic type. An agent (elastic modulus at 95 ° C.: 8 × 10 ^-3 GPa) was obtained.

(5. Preparation of sample for optical characteristic evaluation)
The polarizing plate, the λ / 4 retardation plate, and the transparent conductive film prepared in the above steps 1 to 3 were laminated in this order using the pressure-sensitive adhesive prepared in the above steps 4. The transparent conductive film was laminated so that the conductive layer faces the polarizing plate side. Furthermore, an omnidirectional reflective film (a base material in which an aluminum film is vapor-deposited on one side of a PET film, manufactured by Toray Film Processing Co., Ltd., product name "DMS (DMS)" is used on the surface of the transparent conductive film on the anti-blocking layer side. X42) ”) was laminated so that the vapor-filmed surface was on the adhesive layer side, and used as a sample for evaluating optical characteristics.

<Example 2>
Described in Example 1 with respect to the particle material of the anti-blocking layer, except that an average particle diameter of 3.0 μm (manufactured by Sekisui Plastics Co., Ltd., trade name “XX-104AA”, refractive index 1.495) was used. A transparent conductive film B, a polarizing plate, a λ / 4 retardation plate, and a sample for evaluating optical characteristics were prepared by the same method as in the above.

<Example 3>
Regarding the added particles of the anti-blocking layer, except that the material has an average particle diameter of 1.8 μm (manufactured by Soken Chemical Co., Ltd., trade name “MX180-TAN”, refractive index 1.495), and the number of copies is 0.32. , A transparent conductive film C, a polarizing plate, a λ / 4 retardation plate, and a sample for evaluating optical characteristics were prepared by the same method as described in Example 1.

<Example 4>
A transparent conductive film D was produced by the method described in Example 1 except that the polycarbonate λ / 4 retardation plate described in Example 1 was used as the transparent film base material of the transparent conductive film. The polarizing plate, the transparent conductive film D, and the omnidirectional reflective film described in Example 1 were laminated using the pressure-sensitive adhesive described in Example 1 to prepare a sample for optical property evaluation.

<Comparative Example 1>
A long film substrate (manufactured by Nippon Zeon Co., Ltd., trade name "ZEONOR") having a thickness of 40 μm was put into a take-up sputtering apparatus, and an indium tin oxide layer having a thickness of 25 nm (25 nm thick) was placed on one side thereof as a transparent conductive layer. In an atmosphere of 0.4 Pa consisting of 98% argon gas and 2% oxygen, a sputtering film forming method using a sintered body composed of 97% by weight of indium oxide and 3% by weight of tin oxide was laminated. As a result, the transparent conductive film E was produced. A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film E.

<Comparative Example 2>
Instead of the anti-blocking layer of Example 1, a coating composition obtained by diluting a binder resin (“UNIDIC” manufactured by DIC Corporation, refractive index 1.495) with ethyl acetate was used, and the thickness of the flat portion after drying was 1. A long film base material was coated so as to have a thickness of 0 μm to form a hard coat layer. Subsequently, a hard coat layer, an optical adjustment layer, and a transparent conductive layer were formed on the surface opposite to the hard coat layer by the method described in Example 1 to prepare a transparent conductive film F. A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film F.

<Comparative Example 3>
Regarding the anti-blocking layer, a transparent conductive film G was produced by the method described in Example 1 except that the binder resin was "Opster KZ6734" (manufactured by JSR Corporation, refractive index 1.74). A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film G.

<Comparative Example 4>
Instead of the anti-blocking layer of Example 1, a coating composition obtained by diluting a binder resin (JSR Corporation, “Opstar KZ6734”, refractive index 1.74) with ethyl acetate was used, and the thickness of the flat portion after drying was 1. It was coated to a thickness of 0.0 μm to form a hard coat layer. A hard coat layer, an optical adjustment layer, and a transparent conductive layer were formed on the opposite surface of the hard coat layer by the same method as in Example 1 to prepare a transparent conductive film H. A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film H.

<Comparative Example 5>
Regarding the anti-blocking layer, the binder resin was "Opstar KZ6734" (manufactured by JSR, refractive index 1.74), and the added particles had an average particle diameter of 0.8 μm (manufactured by Sekisui Plastics Co., Ltd., trade name "XX". -183AA ”, refractive index 1.495), the transparent conductive film I was produced by the method described in Example 1. A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film I.

<Comparative Example 6>
Regarding the anti-blocking layer, the binder resin was "Opster KZ6734" (manufactured by JSR, refractive index 1.74), and the added particles had an average particle diameter of 3.0 μm (manufactured by Sekisui Plastics Co., Ltd., trade name "XX". -104AA ”, refractive index 1.495), the transparent conductive film J was produced by the method described in Example 1. A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film J.

<Comparative Example 7>
Regarding the anti-blocking layer, the binder resin was "Opster KZ6734" (manufactured by JSR, refractive index 1.74), and the added particles had an average particle diameter of 1.5 μm (manufactured by Sekisui Plastics Co., Ltd., trade name "XX". A transparent conductive film K was produced by the method described in Example 1 except that it was set to -95AA "). A polarizing plate and a λ / 4 retardation plate were produced by the method described in Example 1, and a sample for optical characteristic evaluation was produced using the transparent conductive film K.

<Comparative Example 8>
The polycarbonate λ / 4 retardation plate described in Example 1 was used as a transparent film base material, and the binder resin for the antiblocking layer was "Opster KZ6734" (manufactured by JSR Corporation, refractive index 1.74). , And the added particles had an average particle diameter of 3.0 μm (manufactured by Sekisui Kasei Kogyo Co., Ltd., trade name “XX-104AA”, refractive index 1.495), and the same method as in Example 1 was used. , A transparent conductive film L was produced. The polarizing plate, the transparent conductive film L, and the omnidirectional reflective film described in Example 1 were laminated using the pressure-sensitive adhesive described in Example 1 to prepare a sample for optical property evaluation.

<Evaluation>
The following items were evaluated for the transparent conductive film and the sample for optical property evaluation produced in Examples and Comparative Examples. The results are shown in Table 1.

(Surface shape measurement)
The maximum roughness Rz of the anti-blocking layer and the distribution density of the raised portion were measured with a non-contact interference microscope (manufactured by Veeco Instruments).

(Haze)
The haze of the anti-blocking layer was measured using a haze meter (model number "HM-150" manufactured by Murakami Color Technology Research Institute) according to the haze (turbidity) of JIS K7136 (2000). Specifically, we evaluated two types of haze, one with a transparent film substrate alone and the other with an anti-blocking layer formed on the transparent film substrate, and calculated the difference between the former and the latter as the haze of the anti-blocking layer. ..

(Measurement of optical characteristics)
For the laminated body sample for optical evaluation, light with a wavelength of 360 to 760 nm was incident from the polarizing plate side using an optical colorimeter (manufactured by Konica Minolta), and spectral evaluation was performed for the reflected light. I evaluated the appearance with. 3A to 3K show the reflection spectra of Examples 1 to 4 and Comparative Examples 2 to 8, respectively. In Comparative Example 1, a base material that had not been subjected to anti-blocking treatment or the like was incorporated, and there was no effect on the optical characteristics due to depolarization. Therefore, the reflection spectrum of Comparative Example 1 was displayed in each graph as a reference and used as a comparison target.
= Evaluation criteria =
◯: Compared with Comparative Example 1, there was no increase in the reflection spectrum in the region of 400 mn to 550 nm. In the visual evaluation, the same blackness as in Comparative Example 1 was confirmed.
X: The reflection spectrum was increased in the region of 400 mn to 550 nm as compared with Comparative Example 1. In the visual evaluation, the brightness was higher than that of Comparative Example 1 and the color was blackish.

(Slippery)
About the produced transparent conductive film A film with a smooth surface (manufactured by Nippon Zeon Corporation, trade name "ZEONOR film ZF-16") is pressure-bonded to the surface of the anti-blocking layer by acupressure, and the films at that time are pressed against each other. The degree of sticking was visually confirmed according to the following criteria (number of samples N = 10).
= Evaluation criteria =
◯: Sticking does not occur, or sticks once, but the film separates and becomes slippery after a lapse of time.
X: The stuck film does not return to its original state and is not slippery.

In the examples, both slipperiness and appearance were good. It was confirmed that the slipperiness was good when the maximum roughness Rz value was 300 nm (0.3 μm) or more.

In the evaluation of optical characteristics, since it was considered that the anti-blocking layer affects the spectrum, Comparative Example 1 in which a long film substrate having no anti-blocking layer was incorporated into the composition was described as a reference. In Examples 1 to 4, it was confirmed that there was no significant difference in the reflection spectra, and the appearance was also good.

On the other hand, among the comparative examples, in the reflection spectra of Comparative Examples 3 and 6 to 8 which did not look good, the reflectance in the range of 400 nm to 550 nm increased as compared with the sample not forming the anti-blocking layer. It was confirmed that there was. It was speculated that the blackness was impaired by this increase in reflectance. As for the other comparative examples, there was no difference in reflectance as in the examples.

1 Transparent film base material 2 Anti-blocking layer 2a (Anti-blocking layer) Flat part 2b (Anti-blocking layer) raised part 3 Hard coat layer 4 Refractive index adjustment layer 5 Transparent conductive layer 10 Transparent conductive film 13a, 13b Fixed layer 20 Polarizer 21 Polarizer 22a, 22b Polarizer protective film 30 Display element 31 Cell substrate 32a, 32b Polarizer 100 Display device with touch function P particles

Claims (9)

A transparent film substrate with a frontal phase difference of 200 nm or less,
An anti-blocking layer provided on one main surface side of the transparent film substrate,
And a transparent conductive layer provided on the main surface side opposite to said anti-blocking layer side of the front Symbol transparent film substrate,
The anti-blocking layer is a cured product layer of a resin composition containing a binder resin and particles.
The content of the particles in the anti-blocking layer is 0.16 to 5 parts by weight with respect to 100 parts by weight of the solid content of the resin composition.
The anti-blocking layer has a flat portion and a raised portion due to the particles on the surface opposite to the transparent film base material side.
The mode particle size of the particles is larger than the thickness of the flat portion of the anti-blocking layer.
A transparent conductive film in which the refractive index np of the particles and the refractive index nb of the binder resin satisfy the following relationship.
| Np-nb | <0.14 The transparent conductive film according to claim 1, wherein the maximum roughness Rz of the surface of the anti-blocking layer on the side opposite to the transparent film substrate side is 0.3 μm or more and 2.5 μm or less. The transparent conductive film according to claim 1 or 2, wherein the distribution density of the raised portion of the anti-blocking layer is 100 pieces / mm ² or more and 1200 pieces / mm ^{2 or less.} The transparent conductive film according to any one of claims 1 to 3, wherein the haze of the anti-blocking layer is 0.7% or more and 3% or less. The transparent conductive film according to claim 1, wherein at least one layer coating layer is formed between the front Symbol transparent conductive layer wherein the transparent film substrate. The transparent conductive film according to any one of claims 1 to 5 , which is arranged between the polarizing plate and the display element. With a polarizing plate
Display element and
A display device with a touch function, comprising the transparent conductive film according to claim 6 , which is arranged between the polarizing plate and the display element. A fixed layer is provided between the transparent conductive film on the anti-blocking layer forming surface side and the polarizing plate or the display element.
The touch according to claim 7, wherein the absolute value of the difference between the maximum value and the minimum value of the refractive index na of the fixed layer, the refractive index np of the particles, and the refractive index nb of the binder resin is 0.14 or less. Display device with function. The display device with a touch function according to claim 7 or 8 , wherein the fixed layer is an adhesive layer or an adhesive layer.

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