JP5878056B2 - Hard coat substrate and transparent conductive film using the same - Google Patents

Description

  The present invention relates to a transparent conductive film which makes a pattern mark and non-pattern part of a patterned transparent conductive film invisible, has little interference unevenness, and has a good appearance in touch panel applications.

  Depending on the detection method of the touch panel, there are a resistance film method, a capacitance method, an optical method, an ultrasonic method, and the like. In particular, in recent years, the market for capacitive touch panels capable of multi-touch in smartphones, tablet personal computers, and the like is increasing. Capacitance method, in particular, projection type touch panel, which is composed of a pair of patterned transparent conductive films, is a method of detecting positional information by detecting the change in capacitance of the touched part. . The transparent conductive film used for the electrostatic capacity method has a pattern portion and a non-pattern portion having a transparent conductive layer, and therefore the film configuration is different between the pattern portion and the non-pattern portion. As a result, patterning marks are recognized, and there is a problem that it does not look good when viewed as a display element such as a touch panel.

  With respect to the above problem, in Patent Document 1, at least two types of undercoat layers are arranged in the transparent conductive layer, and the refractive index and thickness of these undercoat layers are set to specific values, respectively, as a display element. A transparent conductive film with improved appearance has been proposed.

  Further, Patent Document 2 proposes a transparent conductive film that similarly looks good as a display element by providing a hard conductive layer and an intermediate layer set to a specific refractive index and thickness on the transparent conductive layer.

  Patent Document 3 proposes a transparent conductive film that makes the pattern shape inconspicuous even if it is a patterned transparent conductive film by adjusting the refractive index of the hard coat constituting the transparent conductive film.

Japanese Patent No. 4667471 JP 2012-25066 A JP 2010-208169 A

  However, in Patent Document 1, the refractive index of the first undercoat layer from the transparent base film is 1.5 to 1.7, and the patterning process of the transparent conductive layer is performed within the range of the refractive index. The improvement of the color difference (ΔE) between the pattern portion and the non-pattern portion is insufficient. Further, in claim 1 of Patent Document 1, it is described that the undercoat layer farthest from the transparent film substrate is also patterned in the same manner as the transparent conductive layer. This requires at least two patterning steps, which not only raises concerns about the complexity and cost of the process, but if the undercoat layer remains unpatterned, the color difference between the pattern and non-pattern portions is sufficient. It is suggested that there is no improvement. Further, the total optical thickness of the transparent conductive layer including the undercoat layer is 208 to 554 nm, and when a function-imparting layer such as a hard coat is formed on the opposite surface of the transparent conductive treatment layer, the thickness balance between both surfaces is not good. It tends to be uniform, and when the transparent conductive film is annealed, the curling of the film occurs and there is a concern about problems during film processing.

  On the other hand, in Patent Document 2, the appearance is improved by laminating a hard coat layer, an intermediate layer and a tin-doped indium oxide layer (ITO layer) on a transparent base film, but the hard coat layer, the intermediate layer, If the hard coat layer on the back surface is included, at least three coating steps are required, which may be a problem in terms of cost. In addition, when forming a transparent conductive layer including an ITO layer, a low refractive index layer such as silicon oxide is often formed under the ITO layer in order to improve adhesion and visibility. When the configuration is assumed, it is difficult to say that the color difference between the pattern portion and the non-pattern portion is sufficiently improved.

  In Patent Document 3, a transparent conductive film, an undercoat layer, a hard coat layer, a transparent conductive film laminated in the order of a transparent substrate, and a transparent sheet having a coating layer covering the surface of the undercoat layer, a hard coat By optimizing the refractive index of the layer, the pattern shape of the transparent conductive film may be inconspicuous. Specifically, the visibility of the pattern shape is improved by setting the refractive index of the hard coat layer to 1.60 or more and 1.80 or less. Generally, if the refractive index on the substrate is increased, The refractive index difference with the substrate becomes large, and the interference unevenness due to the light interference between the coating film and the substrate becomes conspicuous. For this reason, when a transparent substrate having an easy-adhesion layer having a general refractive index as specified in the examples of Patent Document 3 is used, the use of the transparent sheet as a member of a display element causes poor appearance. There is a concern to bring.

  Therefore, the present invention solves the above-mentioned problems of the prior art, and provides a transparent conductive film that is very attractive even when it is used as a display element, in which the patterning shape of the transparent conductive layer is inconspicuous at low cost. is there.

  The hard coat substrate of the present invention is a hard coat substrate including a transparent substrate, an easy adhesion layer, and a refractive index adjusting layer in this order, and the refractive index at a wavelength of 550 nm of the refractive index adjusting layer is 1.60 to 1.90, the refractive index adjustment layer has a thickness of 0.3 to 5 μm, and the easy-adhesion layer has a refractive index of 1.56 to 1.70 at a wavelength of 550 nm. It is characterized by.

Moreover, the transparent conductive film of the present invention is a transparent conductive film including a transparent conductive layer and a hard coat substrate, the transparent conductive layer is patterned, and the hard coat substrate is transparent. Including a base material, an easy-adhesion layer, a refractive index adjustment layer, and a low refractive index layer in this order, the refractive index at a wavelength of 550 nm of the low refractive index layer is 1.35 to 1.45, The low refractive index layer has a thickness of 5 to 30 nm, the refractive index adjustment layer has a refractive index at a wavelength of 550 nm of 1.60 to 1.90, and the refractive index adjustment layer has a thickness of 0.00. 3 to 5 μm, the refractive index of the easy-adhesion layer at a wavelength of 550 nm is 1.56 to 1.70, the transparent conductive layer is disposed on the low refractive index layer , and the transparent conductive layer The refractive index at a wavelength of 550 nm is 1.8 to 2.3. The thickness of the transparent conductive layer, characterized in that it is a 10 to 30 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the pattern shape of a transparent conductive layer is not conspicuous, and when it is set as a display element, the transparent conductive film which is very good appearance can be provided at low cost.

It is a schematic cross section which shows an example of the transparent conductive film of this invention. It is a schematic cross section which shows the other example of the transparent conductive film of this invention.

  The hard coat substrate of the present invention comprises a transparent substrate, an easy adhesion layer, and a refractive index adjusting layer in this order, and the refractive index at a wavelength of 550 nm of the refractive index adjusting layer is 1.60 to 1.90. The thickness of the refractive index adjusting layer is 0.3 to 5 μm, and the refractive index of the easy adhesion layer at a wavelength of 550 nm is 1.56 to 1.70.

  The transparent conductive film of the present invention comprises a transparent conductive layer and a hard coat substrate, and the hard coat substrate comprises a transparent substrate, an easy-adhesion layer, and a refractive index adjustment layer in this order. The refractive index adjustment layer has a refractive index of 1.60 to 1.90 at a wavelength of 550 nm, the refractive index adjustment layer has a thickness of 0.3 to 5 μm, and the easy-adhesion layer has a refraction at a wavelength of 550 nm. The refractive index is 1.56-1.70, the transparent conductive layer is disposed on the refractive index adjusting layer, and the refractive index of the transparent conductive layer at a wavelength of 550 nm is 1.8-2.3, The transparent conductive layer has a thickness of 10 to 30 nm.

  The transparent conductive film using the hard coat substrate is not very conspicuous in the patterning shape of the transparent conductive layer, and is very attractive even when used as a display element.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an example of the transparent conductive film of the first embodiment of the present invention. In FIG. 1, a transparent conductive film 10 of the present invention is configured by laminating a transparent substrate 11, an easy adhesion layer 12, a refractive index adjusting layer 13, a low refractive index layer 14, and a transparent conductive layer 15 in this order. . Further, the transparent conductive layer 15 is configured by a patterned portion 15a made of the transparent conductive layer 15 and a non-pattern portion 15b from which the transparent conductive layer 15 has been removed. In FIG. 1, the transparent base material 11, the easily bonding layer 12, and the refractive index adjustment layer 13 correspond to the hard coat base material of this invention.

  FIG. 2 is a schematic cross-sectional view showing another example of the transparent conductive film of the second embodiment of the present invention. In FIG. 2, the transparent conductive film 20 of the present invention is configured by laminating a transparent base material 21, an easy adhesion layer 22, a refractive index adjusting layer 23, a low refractive index layer 24 and a transparent conductive layer 25 in this order, A function-imparting layer 26 is disposed on the side of the transparent substrate 21 opposite to the side on which the refractive index adjustment layer 23 is formed. The transparent conductive layer 25 includes a patterned portion 25a that is patterned and made of the transparent conductive layer 25, and a non-pattern portion 25b from which the transparent conductive layer 25 is removed. In FIG. 2, the transparent base material 21, the easy-adhesion layer 22, and the refractive index adjustment layer 23 correspond to the hard coat base material of the present invention. The difference between FIG. 1 and FIG. 2 is only the presence or absence of the function-imparting layer 26, and the other configurations are the same.

<Transparent substrate>
Although the kind is not specifically limited as said transparent base material, Usually, the resin film which has transparency is used. Examples of the resin used for the resin film include polyester resins, polycarbonate resins, poly (meth) acrylic resins, triacetate cellulose resins, polyolefin resins, and the like. From the viewpoint of the above, polyester resins, particularly polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferable. The thickness of the transparent substrate is not particularly limited, but is preferably 10 to 250 μm, more preferably 20 to 188 μm, considering the balance between translucency and strength.

<Easily adhesive layer>
An easy-adhesion layer is formed on the surface of the transparent substrate in order to provide adhesion to the coating film to be coated thereon. The refractive index of the easy adhesion layer at a wavelength of 550 nm needs to be set in the range of 1.56 to 1.70, more preferably 1.60 to 1.68. In order for the transparent conductive film of the present invention to make the pattern of the transparent conductive layer invisible, it is necessary to apply a refractive index adjusting layer having a high refractive index to the transparent substrate. If the refractive index is lower than 1.56, the refractive index difference from the coated refractive index adjusting layer becomes large, and interference unevenness becomes conspicuous. If the refractive index exceeds 1.70, the refractive index with the transparent substrate. The difference becomes large, which is not preferable.

  The easy-adhesion layer may be processed in advance when the transparent substrate is formed, or may be separately formed by applying an easy-adhesion layer by a method such as wet coating, for example. . When the above-mentioned easy adhesion layer is separately formed on the transparent substrate, for example, a polyester resin, an acrylic resin, a urethane resin, an epoxy resin, a polycarbonate resin, or the like is usually used as the material used for the easy adhesion layer. In addition, for the purpose of increasing the refractive index of the easy-adhesion layer, a material having a high refractive index such as titanium oxide may be blended in the easy-adhesion layer, and an aqueous polyester resin and a water-soluble inorganic chelate compound may be added to the easy-adhesion layer. Further, a polyester resin having a fluorene skeleton having a high refractive index may be coated on a transparent substrate to form an easy adhesion layer.

  The thickness of the said easily bonding layer is not specifically limited, Usually, it is about 50-150 nm.

<Refractive index adjustment layer>
A refractive index adjusting layer is formed on the easy adhesion layer. The refractive index at 550 nm of the refractive index adjusting layer needs to be set in the range of 1.60 to 1.90, more preferably 1.65 to 1.80. By setting the refractive index of the refractive index adjusting layer within the above range, in the transparent conductive film of the present invention, the color difference due to the presence or absence of a pattern portion due to patterning of the transparent conductive layer can be reduced. If the refractive index is less than 1.60, the color difference between the pattern part and the non-pattern part cannot be reduced, and if it is higher than 1.90, the difference in refractive index between the transparent substrate and the easy-adhesion layer becomes large. Interference unevenness of the rate adjusting layer is conspicuous, which causes a problem in appearance when a transparent conductive film is formed.

  Further, the thickness of the refractive index adjusting layer needs to be set to 0.3 to 5 μm, and more preferably 0.5 to 3 μm. If the thickness is less than 0.3 μm, the function as a hard coat layer is not fully exhibited, and annealing treatment is performed at 150 ° C. for about 30 minutes for the purpose of crystallization and stabilization of the transparent conductive layer. In this case, the refractive index adjustment layer cannot block the elution of low molecular weight components from the transparent substrate, resulting in optical deterioration (particularly, haze increase) of the transparent conductive film of the present invention. Sometimes. On the other hand, if the thickness is greater than 5 μm, it is not preferable because it causes a decrease in translucency and an increase in haze, and causes inconvenience in terms of workability and cost.

  Since the refractive index adjusting layer is required to have a high refractive index, the refractive index adjusting layer preferably contains a metal oxide such as titanium oxide or zirconium oxide, which is a high refractive index filler. In addition, after applying a coating solution that combines the metal oxide and the ultraviolet curable resin on the easy-adhesion layer, it is refracted by irradiating ultraviolet rays with a high-pressure mercury lamp, metal halide lamp, etc., and curing the coating film. It is preferable to form a rate adjusting layer. That is, in order to increase the efficiency of the manufacturing process, the refractive index adjustment layer is preferably formed by a wet coating method. The wet coating method is not particularly limited, but it is applied by a known method such as roll coating, die coating, air knife coating, blade coating, reverse coating, gravure coating, or micro gravure coating.

  As the material of the ultraviolet curable resin, a material containing a compound having a double bond capable of radical polymerization is usually used. For example, a monomer, a prepolymer, or a polymer having an unsaturated polymerizable functional group such as a (meth) acryloyl group, a vinyl group, a styryl group, or an allyl group can be used. These can be used singly or in combination of two or more. Among them, it is preferable to use a monomer or prepolymer having a (meth) acryloyl group. Moreover, as said ultraviolet curable resin, it is preferable to use the polyfunctional resin which has two or more unsaturated groups (double bond) in which radical polymerization is possible from a viewpoint of coexistence of productivity and hardness.

<Low refractive index layer>
A low refractive index layer is preferably disposed between the refractive index adjusting layer and the transparent conductive layer. By disposing the low refractive index layer, not only can it function as an optical refractive index adjusting layer, but also an effect of improving the adhesion with the transparent conductive layer laminated thereon can be obtained. In the low refractive index layer, if the refractive index at a wavelength of 550 nm is 1.35 to 1.45 and the thickness is 5 to 30 nm, the above effect can be expected.

  As a material constituting the low refractive index layer, for example, silicon oxide, aluminum fluoride, lithium fluoride, magnesium fluoride, calcium fluoride, barium fluoride, sodium fluoride and the like can be used. The low refractive index layer can be formed by a sputtering method, a vacuum deposition method, an ion plating method, a CVD method, etc., and in particular, from the viewpoint of productivity such as film formation by sputtering is fast. preferable.

<Transparent conductive layer>
The transparent conductive layer is formed on the low refractive index layer. When the low refractive index layer is not disposed, the transparent conductive layer is formed directly on the refractive index adjustment layer. The material constituting the transparent conductive layer is not particularly limited as long as it has excellent transparency and high conductivity. For example, tin oxide, indium doped tin oxide (ITO), antimony doped tin oxide (ATO), fluorine doped oxidation. Metal oxides such as tin (FTO), zinc oxide, aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO) can be used. In particular, ITO having high transparency and conductivity is preferable. The transparent conductive layer can be formed by a sputtering method, a vacuum deposition method, an ion plating method, a CVD method, or the like. Among these, a film formation by a sputtering method is preferable from the viewpoint of productivity such as a high film formation speed.

  The transparent conductive layer can be annealed at 150 ° C. for about 30 minutes for the purpose of crystallization and stabilization of the transparent conductive layer, as described above.

  The refractive index of the transparent conductive layer is determined by the material constituting the transparent conductive layer, and the refractive index of the transparent conductive layer at a wavelength of 550 nm is in the range of 1.8 to 2.3. In order to express the color difference suppressing effect of the pattern part and the non-pattern part from the refractive index, the refractive index at a wavelength of 550 nm of the transparent conductive layer is preferably set to 1.9 to 2.2.

  Moreover, 10-30 nm is preferable and, as for the thickness of the said transparent conductive layer, More preferably, it is 12-25 nm. If the thickness is less than 10 nm, the desired resistivity cannot be obtained and the characteristics as an electrode are insufficient, and if it is more than 30 nm, the light transmission tends to be reduced and the optical characteristics tend to be insufficient.

  As shown in FIGS. 1 and 2, the transparent conductive layer can be used after being patterned into a desired pattern depending on the purpose. As a patterning method, for example, a photolithographic method in which a photoresist is applied in a pattern on the transparent conductive layer and etching is used. In FIG. 1 and FIG. 2, the state after the patterning of the transparent conductive layer is a state in which the low refractive index layer remains, but the low refractive index layer may be removed during the patterning.

  The color difference (ΔE) between the reflection chromaticity of the pattern portion made of the transparent conductive layer and the reflection chromaticity of the non-pattern portion from which the transparent conductive layer is removed is preferably 5 or less, more preferably 3 It is as follows. When ΔE is greater than 5, the pattern portion and the non-pattern portion can be clearly recognized, and the appearance may be impaired when the transparent conductive film of the present invention is incorporated in a display element.

Here, the color difference (ΔE) is calculated by the following formula based on the L ^* a ^* b ^* chromaticity diagram.
△ E = (△ L ^{* 2} + △ a ^{* 2} + △ b ^{* 2} ) ^1/2

<Functional layer>
A function-imparting layer may be further disposed on the side of the transparent substrate opposite to the side where the refractive index adjusting layer is formed, as shown in FIG. Examples of the function-imparting layer include a hard coat layer, an AN (anti-Newton ring) layer, an AFP (anti-fingerprint) layer, and an antireflection layer.

  Moreover, when producing the transparent conductive film of this invention, when not using a protective laminate film for process simplification, it is preferable that a film can wind up without blocking (adhering). For this reason, the function-imparting layer preferably has anti-blocking properties.

  For example, when a smooth coating film such as a hard coat layer is applied to both surfaces of a transparent substrate, blocking (sticking) may occur during winding of the film, making it difficult to wind. For this reason, normally, a protective laminate film or the like is bonded to the coated surface on one side to enable winding. However, when the protective laminate film is bonded, one extra step is added to the manufacturing process of the transparent conductive film, which may increase the cost. Therefore, by giving the function-imparting layer a function having a fine irregular shape on the surface of the coating film called anti-blocking property, it is possible to suppress sticking between the coating films, such as a protective laminate film during winding. Winding can be performed without blocking without interposing anything.

  The method for imparting anti-blocking properties to the function-imparting layer is not particularly limited, but a paint containing a specific size filler is applied, and the filler is bleeded out on the surface of the function-imparting layer during drying and curing. There is a method of providing an anti-blocking property by forming a rough structure. In addition, blending multiple resin components with different physical properties and poor compatibility, causing phase separation during drying, precipitating the resin component on the surface of the coating film, and providing anti-blocking properties by forming irregularities on the function-imparting layer There is also a method of making it.

  The function-imparting layer also has a function of suppressing elution of low molecular weight components from the transparent substrate during the annealing treatment of the transparent conductive layer described above. In addition, the function-imparting layer can be expected to suppress curling of the transparent conductive film during the annealing treatment. Therefore, when the thickness of the refractive index adjustment layer on the transparent conductive layer side is a and the thickness of the function-imparting layer on the opposite side is b, the thickness configuration is preferably in the range of 2a> b> 0.5a. If the thickness is set outside the above range, the balance of shrinkage due to heat of both coating films is greatly lost, and there is a concern about curling of the film.

  The function-imparting layer is preferably formed by the aforementioned wet coating method in order to increase the efficiency of the manufacturing process.

<Preparation of refractive index adjusting paint>
Refractive index adjusting paints 1 to 4 were prepared as follows.

(Refractive index adjusting paint 1)
Zirconium oxide dispersion “SZR-K” having an average particle size of 5 nm (manufactured by Sakai Chemical Co., Ltd., solid content concentration: 30% by mass), 100 parts by mass, dipentaerythritol hexaacrylate “KAYARAD DPHA” (manufactured by Nippon Kayaku Co., Ltd.) 10 parts by mass of UV curable resin) and 0.3 parts by mass of photopolymerization initiator “Irgacure 184” (manufactured by BASF) were blended with a disper to prepare a refractive index adjusting paint 1. It was 1.71 when the refractive index in 550 nm of the hardened | cured material of the produced refractive index adjustment coating material 1 was measured.

(Refractive index adjusting paint 2)
A refractive index adjusting paint 2 was prepared in the same manner as the refractive index adjusting paint 1 except that the amount of “KAYARAD DPHA” used was changed to 7.5 parts by mass and the amount of “Irgacure 184” used was changed to 0.2 parts by mass. . It was 1.75 when the refractive index in 550 nm of the hardened | cured material of the produced refractive index adjustment coating material 2 was measured.

(Refractive index adjusting paint 3)
30 parts by mass of ultrafine titanium oxide “TTO-V-3” (manufactured by Ishihara Sangyo Co., Ltd.), 5 parts by mass of “SOLPERSE 36000” (manufactured by Nippon Lubrizol Co., Ltd.) as a dispersant, 65 parts by mass of propylene glycol monomethyl ether, In a plastic container, add zirconia beads with a diameter of 0.1 mm, disperse with a paint shaker (manufactured by Toyo Seiki Co., Ltd.) so that the average particle size of titanium oxide is 30 nm, and finally filter the zirconia beads by filtration. The titanium oxide slurry was prepared by removing.

  100 parts by mass of the prepared titanium oxide slurry, 7 parts by mass of “KAYARAD DPHA”, and 0.3 parts by mass of “Irgacure 184” were blended with a disper to prepare a refractive index adjusting paint 3. It was 1.92 when the refractive index in 550 nm of the hardened | cured material of the produced refractive index adjustment coating material 3 was measured.

(Refractive index adjusting paint 4)
30 parts by mass of “KAYARAD DPHA”, 0.9 parts by mass of “Irgacure 184”, and 70 parts by mass of methyl ethyl ketone (MEK) were blended with a disper to prepare a refractive index adjusting paint 4. It was 1.53 when the refractive index in 550 nm of the hardened | cured material of the produced refractive index adjustment coating material 4 was measured.

  Next, using the refractive index adjusting paints 1 to 4, transparent conductive films were produced as follows.

Example 1
One low-refractive-index easy-adhesion layer surface (refractive index of the easy-adhesion layer) of PET film “Lumirror QT-D0” (thickness: 125 μm) manufactured by Toray Industries, Inc., which is a transparent substrate with both surfaces subjected to easy-adhesion treatment. 58) was coated with an anti-blocking hard coating agent “Z-739” (manufactured by Aika Kogyo Co., Ltd.) with a microgravure coater so that the thickness after drying was 2 μm, and ultraviolet rays were 300 mJ / cm ² with a high-pressure mercury lamp. Irradiated with a light amount and cured, an anti-blocking hard coat layer was formed as a function-imparting layer, and an anti-blocking hard coat treated film was produced.

Refractive index adjusting coating 1 is applied on the surface of the anti-blocking hard coat-treated film on the side opposite to the surface on which the anti-blocking hard coat layer is formed (the refractive index of the easy-adhesion layer: 1.65). Coating was performed so that the thickness after drying was 2 μm, and a refractive index adjusting layer was formed by irradiating and curing ultraviolet rays with a high-pressure mercury lamp at a light amount of 300 mJ / cm ² to prepare a refractive index adjusting hard coat film A. .

(Example 2)
A refractive index adjusting hard coat film B was produced in the same manner as in Example 1 except that the refractive index adjusting paint 2 was used instead of the refractive index adjusting paint 1.

(Example 3)
Silicon oxide was laminated by a magnetron sputtering method on the refractive index adjusting layer of the refractive index adjusting hard coat film A produced in Example 1, and a low refractive index layer (refractive index: 1.40, thickness: 10 nm). ) Was formed. Thereafter, indium-doped tin oxide (ITO) is laminated on the low refractive index layer by magnetron sputtering to form a transparent conductive layer (refractive index: 2.0, thickness: 15 nm). The conductive layer was subjected to a patterning process by a photolithography method to produce a transparent conductive film A having a pattern portion and a non-pattern portion.

Example 4
A transparent conductive film B was produced in the same manner as in Example 3 except that the refractive index adjusted hard coat film B was used in place of the refractive index adjusted hard coat film A.

(Example 5)
Except that PET film “KEB-03W” (thickness: 125 μm, refractive index of both sides easy-adhesion layer: 1.60) manufactured by Teijin DuPont Films Ltd. was used as a transparent base material subjected to easy-adhesion treatment on both sides. A transparent conductive film C was produced in the same manner as in Examples 1 and 3.

(Example 6)
A transparent conductive film D was produced in the same manner as in Example 3 except that the thickness of the transparent conductive layer was 20 nm.

(Comparative Example 1)
A refractive index adjusting hard coat film C was produced in the same manner as in Example 1 except that the refractive index adjusting paint 3 was used instead of the refractive index adjusting paint 1.

(Comparative Example 2)
Example except that PET film “Lumirror U34” (thickness: 125 μm, refractive index of easy-adhesion layer on both sides: 1.51) manufactured by Toray Industries, Inc. was used as a transparent base material subjected to easy adhesion treatment on both sides. The refractive index-adjusted hard coat film D was produced in the same manner as in Example 1.

(Comparative Example 3)
A transparent conductive film E was produced in the same manner as in Example 3 except that the refractive index adjusted hard coat film C was used in place of the refractive index adjusted hard coat film A.

(Comparative Example 4)
In place of the refractive index adjusting paint 1, a refractive index adjusting paint 4 is used, and a PET film “U48” (thickness: 125 μm, double-sided easy-adhesion layer on both sides) is used as a transparent base material having both surfaces subjected to easy adhesion treatment. A transparent conductive film F was produced in the same manner as in Examples 1 and 3 except that the refractive index was 1.58).

(Comparative Example 5)
A transparent conductive film G was produced in the same manner as in Example 3 except that the refractive index adjusted hard coat film D was used instead of the refractive index adjusted hard coat film A.

(Comparative Example 6)
A transparent conductive film H was produced in the same manner as in Examples 1 and 3, except that the thickness of the refractive index adjusting layer was 0.1 μm.

(Comparative Example 7)
In place of the anti-blocking hard coat agent “Z-739”, a function-imparting layer was formed using the refractive index adjusting paint 4 and an attempt was made to produce a transparent conductive film in the same manner as in Examples 1 and 3. At the time of winding up the coating of the rate adjusting layer, sticking of the film occurred, and the subsequent film could not be produced.

  The refractive index of each layer of each film of Examples 1-6 and Comparative Examples 1-6 was measured as follows.

<Measurement of refractive index>
Regarding the refractive index of the refractive index adjusting layer, each refractive index adjusting coating is 500 nm in thickness after drying using a bar coater on an easily-adhesive untreated surface of a 100 μm PET film (“Cosmo Shine A4100” manufactured by Toyobo Co., Ltd.). After coating and drying, the coating film was cured by irradiating ultraviolet rays with a high-pressure mercury lamp at a light amount of 300 mJ / cm ² . Next, a black tape is applied to the entire surface of the film surface opposite to the side on which the coating film is formed, and the absolute value on the coating film side is measured using a reflection spectral film thickness meter ("FE-3000" manufactured by Otsuka Electronics Co., Ltd.). The reflectance was measured, and the refractive index was measured from the reflection spectrum.

  In addition, for the refractive index of the easy-adhesion layer of the transparent substrate, a black tape is pasted on the entire film surface opposite to the side where the easy-adhesion layer is formed, and the reflection spectral film thickness meter is set in the same manner as described above. And measured. Also when the easy adhesion layer was formed on both surfaces of the transparent base material, the black tape was stuck on one film surface, and the refractive index of the easy adhesion layer was measured in the same manner as described above.

  Moreover, about the refractive index of a transparent conductive layer and a low-refractive-index layer, after forming each layer so that thickness may be set to 20 nm by the magnetron sputtering method in the said PET film, the refractive index of each layer is set by the method similar to the above. It was measured.

  Next, each film formed in Examples 1 to 6 and Comparative Examples 1 to 6 was evaluated as follows.

<Measurement of reflection chromaticity>
A black tape is pasted on the surface of each transparent conductive film that is opposite to the surface on which the transparent conductive layer is formed, and a transparent conductive film is used using a multichannel spectrophotometer ("MCPD-3700" manufactured by Otsuka Electronics Co., Ltd.). The reflection spectrum of the pattern part and the non-pattern part of the layer is measured, the L ^* a ^* b ^* of the reflected color is analyzed in the color calculation mode (light source: D65, field of view: 2 degrees), and transparent by the following formula described above. The color difference ΔE between the pattern portion and the non-pattern portion of the conductive layer was calculated.
△ E = (△ L ^{* 2} + △ a ^{* 2} + △ b ^{* 2} ) ^1/2

<Appearance of film>
Each produced film was placed on a test stand equipped with a three-wavelength fluorescent lamp (light quantity: 3000 LUX), and the appearance was visually observed. Interference unevenness in the hard coat film alone and the refractive index exerted on the transparent conductive layer The influence of the interference unevenness of the adjustment layer was evaluated as follows according to the following criteria.

When the color unevenness due to the interference unevenness is very thin: Good When the color unevenness due to the interference unevenness is slightly discernable: Inadequate When the color unevenness due to the interference unevenness can be clearly identified: Not possible

<Curlability after heating>
Each produced film was cut into a size of 100 mm × 100 mm, and the cut out film was left in a thermostatic bath heated to 150 ° C. for 30 minutes and then taken out. Measurement was made and the point with the highest numerical value was taken as the size of the curl. In addition, in the case of the transparent conductive films of Examples 3 to 6 and Comparative Examples 3 to 6, when the curled shape was curled when the transparent conductive layer side was turned up, the size of the curl was expressed as minus (−).

<Film processability>
At the time of producing each film, the workability when the refractive index adjusting paint was applied with a micro gravure coater and when the produced film was wound was evaluated. Specifically, the following evaluation was performed according to the following criteria.

When coating and winding are possible without defects: Good When there is a problem during coating or winding: Inadequate When coating or winding is impossible: Not possible

  The above evaluation results are shown in Tables 1 to 4. In Tables 1 to 4, the structure of each film is also shown.

  From Table 1, in Examples 1 and 2, a refractive index-adjusting hard coat film with less interference unevenness was obtained by optimizing the refractive index of the easy-adhesion layer and the refractive index of the refractive index adjustment layer. I understand.

  Moreover, from Table 2, in Examples 3-6, it turns out that the reflective color difference of the pattern part and non-pattern part of a transparent conductive layer was suppressed. As a result, the transparent conductive films of Examples 3 to 6 were confirmed to be invisible patterning marks. Moreover, in Examples 3-6, it turns out that the interference nonuniformity was able to be suppressed by optimizing the refractive index of an easily bonding layer and a refractive index adjustment layer about an external appearance. Furthermore, in Examples 3-6, it turns out that the curling after a heating is also suppressed and the transparent conductive film without a film workability problem was obtained.

  On the other hand, from Table 3, in Comparative Examples 1 and 2, the refractive index of the easy-adhesion layer and the refractive index of the refractive index adjustment layer are not optimal, and when the appearance is confirmed, color unevenness due to interference unevenness can be clearly identified, and interference It can be seen that the unevenness has worsened.

  In Comparative Example 3, since the refractive index of the refractive index adjustment layer is too high, the refractive index difference between the transparent substrate and the easy adhesion layer increases, and even when the transparent conductive layer is laminated, color unevenness due to interference unevenness is clearly distinguished. It was done.

  In Comparative Example 4, since the refractive index of the refractive index adjusting layer was too low, the reflection color difference between the pattern portion and the non-pattern portion exceeded 5, and the patterning trace was sufficiently recognized.

  In Comparative Example 5, since the refractive index of the easy adhesion layer was too low, the refractive index difference from the refractive index adjustment layer was large, and even when the transparent conductive layer was laminated, color unevenness due to interference unevenness was clearly determined.

  In Comparative Example 6, since the thickness of the refractive index adjustment layer was too thin, the thickness balance with the function-imparting layer on the opposite side was lost, and the film was greatly curled after the heat treatment. Moreover, the hard coat property was insufficient, the film was slightly scratched during film running, and the film processability was also insufficient.

  In Comparative Example 7, since a material having no anti-blocking property was used for the function-imparting layer, the film could not be produced as described above, and therefore Comparative Example 7 is not shown in Table 4.

10, 20 Transparent conductive film 11, 21 Transparent base material 12, 22 Easy adhesion layer 13, 23 Refractive index adjustment layer 14, 24 Low refractive index layer 15, 25 Transparent conductive layer 15a, 25a Pattern part 15b, 25b Non-pattern part 26 Functionality layer

Claims (4)

A transparent conductive film comprising a transparent conductive layer and a hard coat substrate,
The transparent conductive layer is patterned,
The hard coat substrate includes a transparent substrate, an easy adhesion layer, a refractive index adjustment layer, and a low refractive index layer in this order,
The refractive index at a wavelength of 550 nm of the low refractive index layer is 1.35 to 1.45,
The low refractive index layer has a thickness of 5 to 30 nm;
The refractive index of the refractive index adjusting layer at a wavelength of 550 nm is 1.60 to 1.90,
The refractive index adjusting layer has a thickness of 0.3 to 5 μm,
The easy-adhesion layer has a refractive index of 1.56 to 1.70 at a wavelength of 550 nm,
The transparent conductive layer is disposed on the low refractive index layer ,
The transparent conductive layer has a refractive index of 1.8 to 2.3 at a wavelength of 550 nm,
A transparent conductive film, wherein the transparent conductive layer has a thickness of 10 to 30 nm. 2. The transparent conductive material according to claim 1 , wherein a color difference (ΔE) between a reflected chromaticity of the pattern portion made of the transparent conductive layer and a reflected chromaticity of the non-patterned portion from which the transparent conductive layer is removed is 5 or less. Sex film. The refractive index adjustment layer is composed of a metal oxide and an ultraviolet-curable resin, the metal oxide, a transparent conductive film according to claim 1 or 2, zirconium oxide or titanium oxide. Of the transparent substrate, on the side opposite to the side where the refractive index adjusting layer is formed, according to any one of claims 1 to 3, functionalization layer having anti-blocking property are further arranged Transparent conductive film.

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