JP2015052837A - Transparent conductive laminate and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive laminate having a resin layer configured to absorb ultraviolet light, capable of suppressing occurrence of spots on a surface of the resin layer, and also to provide a touch panel.SOLUTION: A transparent conductive laminate 10 includes: a substrate 11; a first transparent electrode layer 13a; a second transparent electrode layer 13b opposing to the first transparent electrode layer across the substrate 11; resin layers 12a, 12b having a function to absorb ultraviolet light and formed at least in one location between the substrate 11 and the first transparent electrode layer 13a and between the substrate 11 and the second transparent electrode layer 13b. The resin layers 12a, 12b include an acrylic monomer, and a resin obtained by copolymerization of an acrylic acid vinyl ester monomer and an ultraviolet light absorber. The mean molecular weight of the resin obtained by the copolymerization is 300 thousand or less.

Description

  The technology of the present disclosure relates to a transparent conductive laminate and a touch panel including the transparent conductive laminate.

  In general, a projected capacitive touch panel includes two electrodes for detecting a change in capacitance. For example, as described in Patent Document 1, the two electrodes face each other with a single transparent substrate interposed therebetween. Each of these two electrodes is formed by patterning a transparent conductive film formed on a substrate, and photolithography is used for patterning the conductive film.

  In the exposure process in photolithography, the resist formed on the conductive film is exposed. In the method described in Patent Document 1, a resin layer is provided between each of the substrate and the two conductive films, and each of the two resin layers has a function of absorbing ultraviolet light having a wavelength in the ultraviolet region. doing. Of the ultraviolet rays irradiated to one resist as exposure light, the two resin layers absorb the ultraviolet rays that have passed through the resist. Thereby, even if the exposure for one resist proceeds in the presence of the other resist, the exposure of the other resist to the exposure of the other resist can be suppressed.

Japanese Patent No. 4683164

  By the way, the ultraviolet ray absorbing function of the resin layer is expressed by the ultraviolet absorber added to the resin layer. On the other hand, when an additive other than the resin is added to the resin that is the main component of the resin layer, streaky spots are likely to occur on the surface of the resin layer when the resin layer is formed. The occurrence of spots on the touch panel is not preferable because the visibility of the display image is reduced. In addition, when adding an ultraviolet absorbing function to a resin layer, a technique for suppressing the occurrence of such spots is required.

  The technology of the present disclosure provides a transparent conductive laminate having a resin layer that absorbs ultraviolet rays, and a transparent conductive laminate that can suppress the occurrence of spots on the surface of the resin layer, and a touch panel. Objective.

  A transparent conductive laminate for solving the above problems includes a substrate, a first transparent electrode layer, a second transparent electrode layer facing the first transparent electrode layer across the substrate, and the substrate. And a first transparent electrode layer, and at least one of the substrate and the second transparent electrode layer, and a resin layer having a function of absorbing ultraviolet rays. The resin layer includes an acrylic monomer, a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber, and the copolymer has an average molecular weight of 300,000 or less.

  In the resin layer having the above-described configuration, the additive that exhibits an ultraviolet absorption function is a copolymer of a vinyl acrylate monomer and an ultraviolet absorber, and the average molecular weight of the copolymer is 300,000 or less. Therefore, in the coating liquid for forming the resin layer, compatibility between the acrylic monomer as the main component and an additive that exhibits an ultraviolet absorbing function is obtained. As a result, the generation of streaks on the surface of the resin layer is suppressed. That is, the occurrence of spots on the surface of the resin layer is suppressed in the transparent conductive laminate including the resin layer that absorbs ultraviolet rays.

In the transparent conductive laminate, the copolymerized resin preferably has an average molecular weight of 1000 or more.
When the resin layer contains an additive, depending on the type of the additive, for example, when processing is performed at a high temperature, the additive may bleed out. Bleeding out of the additive in the touch panel is not preferable because it causes an increase in haze. According to the said structure, since the bleed-out of resin which the acrylic acid vinyl ester monomer and the ultraviolet absorber copolymerized is suppressed in a resin layer, the raise of the haze in a transparent conductive laminated body is suppressed.

In the transparent conductive laminate, the average molecular weight of the copolymerized resin is more preferably 5000 or more.
According to the said structure, the raise of the haze in a transparent conductive laminated body is further suppressed.

In the transparent conductive laminate, the acrylic monomer is preferably a vinyl acrylate monomer.
According to the said structure, the compatibility with the acrylic acid vinyl-ester monomer which is an acryl-type monomer, and the additive which expresses the ultraviolet absorption function further increases in the coating liquid for forming a resin layer.

The touch panel for solving the said subject is equipped with the said transparent conductive laminated body.
According to the said structure, a touch panel provided with the transparent conductive laminated body provided with the resin layer which absorbs an ultraviolet-ray, and the generation | occurrence | production of the spot on the surface of the resin layer was suppressed is obtained. Therefore, the transparency fall in a touch panel is suppressed.

  According to the technique of the present disclosure, the occurrence of spots on the surface of the resin layer can be suppressed in the transparent conductive laminate including the resin layer that absorbs ultraviolet rays.

It is sectional drawing which shows the cross-section of the transparent conductive laminated body in one Embodiment in the technique of this indication. It is sectional drawing which shows the cross-section of the touchscreen in one Embodiment in the technique of this indication. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows the formation process of a resin layer. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows the formation process of a transparent conductive layer. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows the formation process of a resist. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows an exposure process. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows a image development process. It is a figure which shows the manufacturing process of the transparent conductive laminated body in one Embodiment, Comprising: It is a figure which shows an etching process. It is sectional drawing which shows the cross-section of the transparent conductive laminated body in a modification. It is sectional drawing which shows the cross-section of the transparent conductive laminated body in a modification.

  With reference to FIGS. 1-8, one Embodiment of a transparent conductive laminated body and a touch panel is demonstrated. In this embodiment, a transparent conductive laminated body is one of the structural members of a touch panel.

[Configuration of transparent conductive laminate]
With reference to FIG. 1, the structure of a transparent conductive laminated body is demonstrated.
As shown in FIG. 1, the transparent conductive laminate 10 includes a transparent substrate 11, two resin layers 12 a and 12 b that face each other across the substrate 11, and a substrate 11 and the resin layers 12 a and 12 b. Two transparent electrode layers 13a and 13b facing each other are provided. On the surface of the substrate 11, a resin layer 12a and a transparent electrode layer 13a are laminated in this order. On the back surface of the substrate 11, a resin layer 12b and a transparent electrode layer 13b are laminated in this order. The transparent electrode layer 13a is an example of a first transparent electrode layer, and the transparent electrode layer 13b is an example of a second transparent electrode layer.

  The substrate 11 is, for example, a glass plate or a resin film. The forming material of the glass plate and the forming material of the resin film are not particularly limited as long as the material satisfies the strength required for the substrate in the transparent electrode layer forming process and the subsequent process. The resin film forming material is, for example, at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polysulfone, polyarylate, cyclic polyolefin, and polyimide. The thickness of the substrate 11 is preferably 10 μm or more and 200 μm or less. If the thickness of the substrate 11 is within such a range, the transparent conductive laminate 10 can be thinned, and the flexibility of the substrate 11 can be obtained.

  The substrate 11 may contain various additives and stabilizers. Examples of the additives and stabilizers include antistatic agents, plasticizers, lubricants, and easy adhesives. The substrate 11 is subjected to corona treatment, low-temperature plasma treatment, ion bombardment treatment, chemical treatment, or the like as pretreatment in order to improve adhesion between the layer laminated on the substrate 11 and the substrate 11. Also good.

  The resin layers 12a and 12b have a function of improving the mechanical strength of the transparent conductive laminate 10, and a function of absorbing ultraviolet rays that are light having a wavelength in the ultraviolet region. The wavelength in the ultraviolet region is about 200 nm to about 380 nm, and the wavelength in the visible region is about 380 nm to about 780 nm.

The resin layers 12a and 12b include an acrylic monomer and a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber.
The acrylic monomer is a monomer that polymerizes in response to light having a wavelength in the ultraviolet region, for example, at least selected from the group consisting of a carboxyl group-containing monomer, a cyanoacrylate monomer, an acrylate monomer, and a vinyl acrylate monomer. One. The acrylic monomer may be one selected from the above group or two or more selected from the above group.

The carboxyl group-containing monomer is, for example, any one selected from the group consisting of acrylic acid, methacrylic acid, and maleic acid.
The cyanoacrylate monomer is, for example, any one selected from the group consisting of acrylonitrile and (meth) acrylonitrile.

  Acrylic acid ester monomers include, for example, methyl acrylate, methyl (meth) acrylate, ethyl acrylate, ethyl (meth) acrylate, propyl acrylate, propyl (meth) acrylate, butyl acrylate, butyl (meth) acrylate, acrylonitrile, (meth) acrylonitrile , Glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl acrylate, hydroxybutyl (meth) acrylate, cyclohexyl It is at least one selected from the group consisting of (meth) acrylate and isobornyl acrylate. The acrylate monomer may be one selected from the above group or two or more selected from the above group.

  The vinyl acrylate monomer is at least one selected from the group consisting of, for example, alkenyl acrylate and alkenyl (meth) acrylate. The alkenyl acrylate ester is, for example, at least one selected from the group consisting of vinyl acrylate and isopropenyl acrylate. The (meth) acrylic acid alkenyl ester is at least one selected from the group consisting of vinyl (meth) acrylate and isopropenyl (meth) acrylate, for example. As the vinyl acrylate monomer, one type of compound may be used alone, or two or more types of compounds may be used in combination.

  Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, benzoate-based, salicylate-based, triazine-based, and cyanoacrylate-based ultraviolet absorbers. The ultraviolet absorber preferably has a polymerizable vinyl group. For example, 2- (2′-hydroxy-5′-methacryloxyethylphenyl) 2H-benzotriazole, 2-hydroxy-4- (methacrylic). Oxy) benzophenone and phenyl-5-methacryloxymethyl salicylate. The ultraviolet absorber may be one selected from the above group or two or more selected from the above group.

The vinyl acrylate monomer copolymerized with the ultraviolet absorber is at least one selected from the vinyl acrylate monomers exemplified above.
The average molecular weight of a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber is 300,000 or less. If the monomer copolymerized with the ultraviolet absorber is a vinyl acrylate monomer and the copolymer has an average molecular weight of 300,000 or less, in the resin in which the vinyl acrylate monomer and the ultraviolet absorber are copolymerized, Compatibility with acrylic monomers is obtained. As a result, the generation of streaks on the surfaces of the resin layers 12a and 12b is suppressed.

  The average molecular weight of the resin obtained by copolymerizing the vinyl acrylate monomer and the ultraviolet absorber is preferably 1000 or more. Usually, when the resin contains an additive, depending on the combination of the resin and the additive, for example, when the resin is cured at a high temperature, the additive may bleed out. Bleeding out of the additive is not preferable because it causes an increase in haze in the resin layers 12a and 12b. In this respect, if the average molecular weight of the resin obtained by copolymerizing the vinyl acrylate monomer and the ultraviolet absorber is 1000 or more, the occurrence of bleeding out is suppressed. Therefore, an increase in haze is suppressed in the transparent conductive laminate 10. The average molecular weight of the resin obtained by copolymerizing the vinyl acrylate monomer and the ultraviolet absorber is more preferably 5000 or more. If the average molecular weight of the resin in which the vinyl acrylate monomer and the ultraviolet absorber are copolymerized is 5000 or more, the occurrence of bleed out is further suppressed.

The thickness of the resin layers 12a and 12b is not limited, but is preferably 0.5 μm or more and 15 μm or less.
As a method for forming the resin layers 12a and 12b, coating using a coating liquid is employed, and the coating liquid contains the solid content of the resin layers 12a and 12b. The coating liquid for forming the resin layers 12a and 12b contains an acrylic monomer, a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber, and a solvent.

  The solvent contained in the coating liquid is not particularly limited as long as it is a liquid that dissolves or disperses an acrylic monomer and a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber. Specific examples of the solvent include ethanol, isopropyl alcohol, isobutyl alcohol, benzene, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, methyl cellosolve, ethyl cellosolve, butyl cellosolve. , Methyl cellosolve acetate, propylene glycol monomethyl ether acetate and the like. These solvents may be used alone or as a mixture of two or more solvents.

  The blending ratio of the resin (B) obtained by copolymerizing the acrylic monomer (A), the vinyl acrylate monomer, and the ultraviolet absorber and the solvent (C) is A: B: C = 20 wt% or more and 60 wt% or less. : 5% by weight or more and 40% by weight or less: 20% by weight or more and 60% by weight or less is preferable. When the blending ratio is in the above range, an ultraviolet absorbing function can be appropriately added to the resin layers 12a and 12b, and occurrence of bleed out can be suppressed.

  As materials for the transparent electrode layers 13 a and 13 b, various materials can be used according to the characteristics and applications required for the transparent conductive laminate 10. For example, the material of the transparent electrode layers 13a and 13b includes any one of indium oxide, zinc oxide, and tin oxide, or two or three kinds of mixed oxides thereof. Further, additives may be added to the above materials. Further, for example, the transparent electrode layers 13a and 13b may be formed from a fibrous metal such as a metal nanowire.

  The transparent electrode layers 13a and 13b are patterned into a predetermined shape. For example, the transparent electrode layer 13a has a pattern in which a plurality of conductive regions extending in the X direction are arranged side by side in the Y direction perpendicular to the X direction. The transparent electrode layer 13b facing the transparent electrode layer 13a has a pattern in which a plurality of conductive regions extending in the Y direction are arranged in parallel with an interval in the X direction. For example, the conductive region is formed in a linear shape or a shape in which a plurality of rhombuses are connected in one direction. A region between adjacent conductive regions becomes a non-conductive region insulated from the conductive region. Each of the conductive regions is connected to a circuit that detects a change in capacitance formed in the conductive region by a change in current. When a human finger or the like approaches the conductive region, the capacitance changes. Based on the detection of the change in capacitance, the contact position of a human finger or the like is determined.

  The transparent conductive laminate 10 preferably has a light transmittance of 60% or more at a wavelength of 400 nm and a light transmittance of 20% or less at a wavelength of 365 nm. When the light transmittance is in the above range, when the resist is exposed to ultraviolet rays, the light that has not been absorbed by one resist can be accurately suppressed from reaching the other resist. In order to enhance such effects, it is preferable that the light transmittance at a wavelength of 400 nm of the resin layers 12a and 12b is 80% or more and the light transmittance at a wavelength of 365 nm is 20% or less.

  Further, in the stacking direction of the transparent conductive laminate 10, a portion where the conductive region of the transparent electrode layer 13a and the conductive region of the transparent electrode layer 13b overlap, a non-conductive region of the transparent electrode layer 13a, and a non-conductive layer of the transparent electrode layer 13b. It is preferable that the difference in total light transmittance from the portion overlapping with the region is 1.5% or less, and the transmitted hue b * difference is 2.0 or less. If the total light transmittance and the transmitted hue difference are within the above ranges, the pattern shape becomes inconspicuous even when the transparent electrode layer 13a and the transparent electrode layer 13b are formed in different patterns. Improves.

  In the transparent conductive laminate 10, the thermal shrinkage rate at 150 ° C. for 30 minutes is preferably 0.5% or less. When the thermal shrinkage rate is within the above range, the laminate is suppressed from shrinking due to heat applied to the transparent electrode layers 13a and 13b and the resist drying step. As a result, pattern displacement between the transparent electrode layer 13a and the transparent electrode layer 13b is suppressed.

  As shown in FIG. 2, a cover layer 30 made of glass or the like is laminated on the transparent electrode layer 13 a on the surface side of the substrate 11 through an adhesive layer to constitute a touch panel 31. The surface of the cover layer 30 becomes a contact surface such as a human finger. Further, a display panel 32 such as a liquid crystal panel is laminated on the transparent electrode layer 13 b on the back side of the substrate 11, and a display device 33 is configured by the touch panel 31 and the display panel 32.

[Method for producing transparent conductive laminate]
With reference to FIGS. 3-8, the manufacturing method of a transparent conductive laminated body is demonstrated.
As shown in FIG. 3, first, the resin layer 12 a is formed on the surface of the substrate 11, and the resin layer 12 b is formed on the back surface of the substrate 11.

  The resin layers 12a and 12b are formed by applying a coating solution obtained by dissolving a resin or the like as a main component in a solvent to the substrate 11 and then curing it. As a coating method, a known coating method such as a die coater, curtain flow coater, roll coater, reverse roll coater, gravure coater, knife coater, bar coater, spin coater, or micro gravure coater is used.

  As shown in FIG. 4, the transparent conductive layer 14 a is then formed on the surface of the resin layer 12 a on the surface side of the substrate 11, and the transparent conductive layer on the surface of the resin layer 12 b on the back surface side of the substrate 11. 14b is formed.

  The transparent conductive layers 14a and 14b are formed by a known film formation method. For example, when the transparent conductive layers 14a and 14b are formed of indium tin oxide (ITO), the transparent conductive layers 14a and 14b are formed by a chemical vapor deposition method such as a vacuum deposition method or a sputtering method, or a chemical method such as a CVD method. It is formed by a chemical vapor deposition method or the like. In the case where the transparent conductive layers 14a and 14b are formed of a fibrous metal, the solution in which the fibrous metal is dispersed is applied to the substrate 11 by a known coating method or printing method, so that the transparent conductive layer Layers 14a and 14b are formed.

  In addition, after the resin layer 12a and the transparent conductive layer 14a are continuously formed on the front surface side of the substrate 11, the resin layer 12b and the transparent conductive layer 14b are continuously formed on the back surface side of the substrate 11. Also good. In short, before the resist is formed, a laminate including the resin layer 12a and the transparent conductive layer 14a on the surface of the substrate 11 and the resin layer 12b and the transparent conductive layer 14b on the back surface of the substrate 11 is formed. It only has to be done.

  Next, as shown in FIG. 5, a resist 15 a is formed on the surface of the transparent conductive layer 14 a on the front surface side of the substrate 11, and a resist 15 b is formed on the surface of the transparent conductive layer 14 b on the back surface side of the substrate 11. It is formed.

  As the resists 15a and 15b, negative resists or positive resists may be used. A known material is used for the resists 15a and 15b, and the resists 15a and 15b are formed by a known method.

  As shown in FIG. 6, next, a stacked body in which the resists 15a and 15b are formed is disposed between the two light sources 18a and 18b that irradiate the resists 15a and 15b with light. The light sources 18a and 18b emit light composed of light having a wavelength in the ultraviolet region and light having a wavelength in the visible region. On the surface side of the substrate 11, between the resist 15a and the light source 18a, a mask 16a having a pattern corresponding to the pattern of the transparent electrode layer 13a from the side closer to the resist 15a, and an optical that blocks light having a wavelength in the visible region. The filter 17a is arranged in this order. On the back side of the substrate 11, between the resist 15b and the light source 18b, the mask 16b having a pattern corresponding to the pattern of the transparent electrode layer 13b and the light having a wavelength in the visible region are blocked from the side closer to the resist 15b. The optical filter 17b is arranged in this order.

  Then, the resist 15a is exposed to light from the light source 18a to expose the resist 15a, and the resist 15b is exposed to light from the light source 18b to the resist 15b. The exposure of the resist 15a and the exposure of the resist 15b are performed simultaneously. Alternatively, the exposure of the resist 15a and the exposure of the resist 15b may be performed separately before the development of the resist 15a and before the development of the resist 15b. At this time, since light having a wavelength in the visible region is blocked by the optical filters 17a and 17b, the resists 15a and 15b are exposed to light having a wavelength in the ultraviolet region among the light emitted from the light sources 18a and 18b.

  Here, since the resin layers 12a and 12b have a function of absorbing ultraviolet rays, of the light irradiated to the resist 15a from the light source 18a through the optical filter 17a, the light not absorbed by the resist 15a is It is absorbed by the resin layers 12a and 12b. Of the light irradiated to the resist 15b from the light source 18b through the optical filter 17b, the light not absorbed by the resist 15b is absorbed by the resin layers 12a and 12b. Therefore, it is possible to suppress the light applied to one resist from being transmitted through the laminate and exposing the other resist.

  In addition, the wavelength of the light blocked by the optical filters 17a and 17b and the wavelength of the light absorbed by the resin layers 12a and 12b are adjusted to adjust the wavelength of the exposure light and the light absorbed by the resin layers 12a and 12b. Therefore, exposure of the resists 15a and 15b and absorption of unnecessary exposure light are performed accurately.

  Next, as shown in FIG. 7, when the resists 15a and 15b are of the negative type, the unexposed portions by the exposure of the resists 15a and 15b are removed by the developer. Alternatively, in the case where the resists 15a and 15b are positive, the portions exposed by the exposure of the resists 15a and 15b are removed by the developer. Thereby, patterns corresponding to the masks 16a and 16b are formed on the resists 15a and 15b. That is, a pattern set as a pattern of the transparent electrode layers 13a and 13b is formed on the resists 15a and 15b.

  As shown in FIG. 8, the exposed portion of the transparent conductive layer 14a is then etched according to the pattern of the resist 15a, and the exposed portion of the transparent conductive layer 14b is etched according to the pattern of the resist 15b. A known method is used as the etching method. Thereby, the transparent conductive layer 14a is patterned to form the transparent electrode layer 13a, and the transparent conductive layer 14b is patterned to form the transparent electrode layer 13b. The remaining portions of the transparent conductive layers 14a and 14b become conductive regions in the transparent electrode layers 13a and 13b, and the removed portions of the transparent conductive layers 14a and 14b become non-conductive regions in the transparent electrode layers 13a and 13b. Then, the transparent conductive laminate 10 is obtained by removing the resists 15a and 15b.

  In addition, it is preferable that each said process is performed by a roll-to-roll system. According to this, since a transparent conductive laminated body can be manufactured efficiently, the time concerning manufacture of the transparent conductive laminated body 10 is shortened.

  In addition, as FIG. 9 shows, either one of the resin layers 12a and 12b may be omitted. FIG. 9 shows the transparent conductive laminate 20 from which the resin layer 12b is omitted. In short, the resin layer may be provided between at least one of the substrate 11 and the transparent electrode layer 13a and between the substrate 11 and the transparent electrode layer 13b. Moreover, the transparent conductive laminated body 10 may be provided with another layer between the substrate 11 and the transparent electrode layers 13a and 13b. Examples of the other layer include a layer for adjusting visible light transmission characteristics in the transparent conductive laminate 10.

  Further, as shown in FIG. 10, the substrate 11 may have a plurality of layers. In the transparent conductive laminate 21 shown in FIG. 10, the substrate 11 includes two sub-substrates 11a and 11b and an adhesive layer 22 that bonds the sub-substrate 11a and the sub-substrate 11b together. Examples of the resin used for the adhesive layer 22 include an acrylic resin, a silicone resin, or a rubber resin. For the adhesive layer 22, it is preferable to use a resin excellent in cushioning properties and transparency.

  In such a method for producing a transparent conductive laminate, the resin layer 12a and the transparent conductive layer 14a are laminated on the surface of the sub-substrate 11a, and the resin layer 12b and the transparent conductive layer 14b are laminated on the surface of the sub-substrate 11b. And the back surface of the sub-board | substrate 11a with which each structural member was laminated | stacked, and the back surface of the sub-board | substrate 11b are bonded together by the adhesion layer 22. FIG. Thereafter, the transparent conductive laminate 21 is manufactured through the same steps as those shown in FIGS.

(Example)
The characteristic which the transparent conductive laminated body mentioned above has is demonstrated using the specific Example given below and a comparative example.

<Example 1>
Pentaerythritol tetraacrylate was used as the acrylic monomer, lauryl acrylate was used as the vinyl acrylate monomer, and 2- (2′-hydroxy-5′-methacryloxyethylphenyl) 2H-benzotriazole was used as the ultraviolet absorber. A copolymer having an average molecular weight of about 1000 is obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber by a radical polymerization reaction using 2-2'-azobisisobutyronitrile as a polymerization initiator. Got. Next, using methyl isobutyl ketone as a solvent, the acrylic monomer, the copolymer, and the solvent are mixed at a mixing ratio of 40% by weight: 20% by weight: 40% by weight to form a resin layer. A coating solution was obtained.

  A polyethylene terephthalate film having a thickness of 125 μm was used as a substrate, and a coating liquid for forming a resin layer was applied to the surface of the substrate using a microgravure method. And the coating film which consists of a coating liquid for forming a resin layer was dried for 2 minutes in 80 degree nitrogen atmosphere, and the resin layer of thickness 5 micrometers was obtained as a resin layer of Example 1. FIG.

  Next, a 20 nm thick transparent conductive layer made of indium tin oxide (ITO) was formed on the resin layer by a sputtering method. And the transparent conductive laminated body of Example 1 was obtained by patterning a transparent conductive layer.

<Production conditions>
Acrylic monomer: Pentaerythritol tetraacrylate (Light acrylate PE-4A: Kyoeisha Chemical)
Acrylic acid vinyl ester monomer: Lauryl acrylate (Light acrylate LA: Kyoeisha Chemical)
Ultraviolet absorber: 2- (2′-hydroxy-5′-methacryloxyethylphenyl) 2H-benzotriazole (DAINSORB T-31: Daiwa Kasei)
Solvent: Methyl isobutyl ketone (Wako Pure Chemical Industries)
Average molecular weight of copolymer: about 1000
Mixing ratio of acrylic monomer, copolymer and solvent: [acrylic monomer: copolymer: solvent] = [40 wt%: 20 wt%: 40 wt%]
Resin layer formation method: Microgravure Resin layer thickness: 5 μm
Coating film drying temperature: 80 degrees Substrate material: Polyethylene terephthalate Substrate thickness: 125 μm
Material for forming transparent conductive layer: Indium tin oxide (ITO)
Formation method of transparent conductive layer: Sputtering Transparent conductive layer thickness: 20 nm
<Example 2>
The average molecular weight of the copolymer contained in the coating solution for forming the resin layer is about 5000, and the other conditions are the same as in Example 1, and the resin layer of Example 2 and the transparent of Example 2 are used. A conductive laminate was obtained.

<Example 3>
The average molecular weight of the copolymer contained in the coating liquid for forming the resin layer is about 10,000, and the other conditions are the same as in Example 1, and the resin layer of Example 3 and Example 3 A transparent conductive laminate was obtained.

<Example 4>
The average molecular weight of the copolymer contained in the coating liquid for forming the resin layer is about 50,000, and the other conditions are the same as in Example 1, and the resin layer of Example 4 and Example 4 A transparent conductive laminate was obtained.

<Example 5>
The average molecular weight of the copolymer contained in the coating solution for forming the resin layer is about 300,000, and the other conditions are the same as in Example 1, and the resin layer of Example 5 and Example 5 A transparent conductive laminate was obtained.

<Example 6>
The average molecular weight of the copolymer contained in the coating liquid for forming the resin layer is about 500, and the other conditions are the same as in Example 1 except that the resin layer of Example 6 and the transparent of Example 6 are transparent. A conductive laminate was obtained.

<Comparative Example 1>
The average molecular weight of the copolymer contained in the coating liquid for forming the resin layer is about 500,000, and the other conditions are the same as in Example 1, and the resin layer of Comparative Example 1 and Comparative Example 1 A transparent conductive laminate was obtained.

<Comparative Example 2>
Instead of the vinyl acrylate monomer, ethylene glycol diglycidyl ether and an ultraviolet absorber are copolymerized by a radical polymerization reaction using 2-2'-azobisisobutyronitrile as a polymerization initiator to obtain an average molecular weight of about The copolymer of Comparative Example 2 was 10,000. Next, using methyl isobutyl ketone as the solvent, the acrylic monomer, the copolymer of Comparative Example 2, and the mixing ratio of the solvent were stirred under the conditions of 40 wt%: 20 wt%: 40 wt%, A coating solution for forming the resin layer of Comparative Example 2 was obtained. Then, the resin layer of Comparative Example 2 and the transparent conductive laminate of Comparative Example 2 were obtained in the same manner as in Example 1 except for the coating solution.

<Evaluation method>
For each of the resin layers of Example 1 to Example 6 and the resin layers of Comparative Examples 1 and 2, using a image clarity measuring instrument (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.), JIS-K7105 Based on -1981, the haze value was measured. Under the present circumstances, the haze in the atmosphere of normal temperature normal pressure (23 degreeC1 atmosphere) and the haze after heating at 150 degreeC for 1 hour were measured. Moreover, haze increase value ((DELTA) Haze) was computed according to following formula 1 by making haze in the atmosphere of normal temperature normal pressure into H1, and setting haze after heat processing to H2. Then, the level at which the haze increase value is 0.1% or less is determined to be a level at which no haze increases after the heat treatment, and the level at which the haze increase value exceeds 0.1% is determined by haze after the heat treatment. Judged to be an increased level.

ΔHaze = H2-H1
Also, after applying a matte black paint to the surface of the resin layer of Example 1 to Example 6 and the surface of the resin layer of the comparative example, the surface of the resin layer directly under the fluorescent lamp (three-wave fluorescent lamp) Was visually confirmed to determine whether or not there were streaky spots on the surface of the resin layer.

  Table 1 shows the results of evaluating the transparent conductive laminates of Examples 1 to 6 and Comparative Examples 1 and 2 by the above evaluation method.

表１に示されるように、共重合体の平均分子量が３０万を越える比較例１は、樹脂層の表面にスジの発生が確認された。また、紫外線吸収剤と共重合されるモノマーがエチレングリコールジグリシジルエーテルであって、共重合体の平均分子量が３０万以下である比較例２においても、樹脂層の表面にスジの発生が確認された。

As shown in Table 1, in Comparative Example 1 in which the average molecular weight of the copolymer exceeded 300,000, the generation of streaks on the surface of the resin layer was confirmed. Further, in Comparative Example 2 where the monomer copolymerized with the ultraviolet absorber is ethylene glycol diglycidyl ether and the average molecular weight of the copolymer is 300,000 or less, generation of streaks on the surface of the resin layer was confirmed. It was.

  On the other hand, in Examples 1 to 6 in which the average molecular weight of the copolymer was 300,000 or less, no generation of streaks was confirmed. Therefore, it is shown that when the monomer copolymerized with the UV absorber is a vinyl acrylate monomer and the average molecular weight of the copolymer is 300,000 or less, the generation of streaks on the surface of the resin layer can be suppressed. It was.

  Further, in Example 6 in which the average molecular weight of the copolymer was smaller than 1000, the haze increased after the heat treatment. On the other hand, in Examples 1 to 5, in which the average molecular weight of the copolymer was 1000 or more, no change in haze was confirmed after the heat treatment. Therefore, it was shown that if the average molecular weight of the copolymer contained in the resin layer is 1000 or more, an increase in haze can be suppressed. Further, in Examples 2 to 5 in which the average molecular weight of the copolymer is 5000 or more, it is recognized that the haze increase value is 0.05% or less, and the suppression of the haze increase is very good. It was.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The resin layers 12a and 12b include a resin obtained by copolymerizing a vinyl acrylate monomer and an ultraviolet absorber as an additive for adding a function of absorbing ultraviolet rays to the resin layers 12a and 12b. The average molecular weight of the copolymerized resin is 300,000 or less. This improves the compatibility of the copolymerized resin with the acrylic monomer. As a result, generation of streaks on the surfaces of the resin layers 12a and 12b can be suppressed in the formation process of the resin layers 12a and 12b.

  (2) Since the average molecular weight of the copolymerized resin is 1000 or more, occurrence of bleed out is suppressed, and an increase in haze in the transparent conductive laminate 10 is suppressed. Therefore, a decrease in transparency of the transparent conductive laminate 10 and the touch panel 31 is suppressed.

  DESCRIPTION OF SYMBOLS 10, 20, 21 ... Transparent electroconductive laminated body, 11 ... Board | substrate, 11a, 11b ... Sub-board | substrate, 12a, 12b ... Resin layer, 13a, 13b ... Transparent electrode layer, 14a, 14b ... Transparent conductive layer, 15a, 15b ... Resist, 16a, 16b ... mask, 17a, 17b ... optical filter, 18a, 18b ... light source, 22 ... adhesive layer, 30 ... cover layer, 31 ... touch panel, 32 ... display panel, 33 ... display device.

Claims (5)

A substrate,
A first transparent electrode layer;
A second transparent electrode layer facing the first transparent electrode layer across the substrate;
A resin layer provided between at least one of the substrate and the first transparent electrode layer and between the substrate and the second transparent electrode layer and having a function of absorbing ultraviolet rays;
The resin layer includes an acrylic monomer, a resin obtained by copolymerization of a vinyl acrylate monomer and an ultraviolet absorber,
The copolymerized resin has an average molecular weight of 300,000 or less. The transparent conductive laminate according to claim 1, wherein the copolymerized resin has an average molecular weight of 1000 or more. The transparent conductive laminate according to claim 1 or 2, wherein the copolymerized resin has an average molecular weight of 5000 or more. The transparent conductive laminate according to claim 1, wherein the acrylic monomer is a vinyl acrylate monomer.   A touch panel provided with the transparent conductive laminated body of any one of Claims 1-4.

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