JP6098424B2 - Conductive sheet and touch panel - Google Patents

Description

The present disclosure, polythiophene-based conductive agent and conductive particles and the including conductive sheet, and to a touch panel comprising a conductive sheet.

  The resistive touch panel converts a pressure applied to a part of the conductive sheet into an electrical signal, and detects a position where the pressure is applied on the conductive sheet. Such resistive touch panels can be used for portable devices such as game machines and electronic dictionaries because operations such as pressing and writing can be output as electrical signals.

  Among the conductive sheets provided in the resistive touch panel, a sheet that employs a conductive polymer as a conductor satisfies high flexibility. For example, the conductive sheet described in Patent Document 1 employs a coating composition containing a polythiophene-based conductive agent as a conductor. Since the conductive sheet having high flexibility is less likely to be cracked by the application of pressure, it is responsible for extending the life of the resistive touch panel.

  On the other hand, a conductive sheet using a conductive polymer is in contact with an oxide semiconductor layer such as ITO (Indium Tin Oxide), which is a different type of semiconductor, in order to detect a position where pressure is applied. At this time, the contact resistance between the conductive sheet containing the polythiophene-based conductive agent and the ITO is higher than the contact resistance between the ITO films, which increases the input load of the resistive film type touch panel.

  Therefore, the conductive sheet described in Patent Document 2 includes hydrophilic particles in the conductive layer for the purpose of suppressing such an input load, and improves the contact between the oxide semiconductor layer and the conductive layer. Moreover, the electroconductive sheet of patent document 3 to patent document 5 contains the electroconductive particle in the electroconductive layer for the purpose of suppressing input load similarly.

JP 2006-289780 A JP 2007-321131 A JP-T-2006-502254 JP 2009-037752 Special table 2011-500196 gazette

  By the way, in addition to ensuring the sensitivity to pressing and writing, the resistive touch panel is also required to display a clearer image without adversely affecting an image of a liquid crystal display or the like that is used by overlapping the touch panel. However, the resistive touch panel has a structure in which the two conductive surfaces that serve as the upper and lower electrodes are placed facing each other with a gap of several hundreds of micrometers that is likely to cause light interference, and therefore a Newton ring is generated on the touch panel. , Easy to disturb the image. In particular, in order to increase the sensitivity of the touch panel, it is effective to reduce the distance between the upper and lower electrodes, but a Newton ring can be visually recognized more clearly, and a countermeasure is desired.

  In order to suppress Newton's ring, it is effective to make the conductive surface uneven and scatter the interference light appropriately. On the other hand, this conductive surface unevenness also scatters the transmitted light from the display and distorts the image. This is difficult to achieve.

  Such requests are not limited to the electrodes of resistive film type touch panels, but include electrodes having a conductive layer on a base material such as electrodes of capacitive touch panels and electromagnetic wave shields on touch panels, and are disposed on top of other members. Common in the conductive sheet for

The techniques of this disclosure, polythiophene conductive and a conductive agent and conductive particles, high anti-Newton ring properties and, can der compatibility between suppression of glare of images to be viewed through the conductive sheet Ru conductive sheet, And it aims at providing a touch panel.

  In the technique of the present disclosure, one embodiment of a method for producing a conductive sheet includes a step of applying a coating liquid to a substrate to form a coating film, and a step of drying the coating film to form a conductive layer. . On the surface of the conductive layer, the arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less, and the load length ratio (tp) is a cutting level c. = 50%, 25% or more and 45% or less, and the average interval (Sm) of the unevenness is 5 μm or more and 20 μm or less. The coating liquid contains a polythiophene-based conductive agent and conductive particles, and the film thickness a of the conductive layer and the minor axis diameter b of the conductive particles satisfy the following formulas 1 and 2.

a> 100 nm Formula 1
1.5 <b / a <5 Formula 2
In the manufacturing method of the conductive sheet according to the technique of the present disclosure, the coating liquid further includes a binder and a silane coupling compound, and the mass of the polythiophene-based conductive agent is 100 in the coating liquid. The mass part of the conductive particles is preferably 20 or more and 100 or less, and the mass part of the silane coupling compound is preferably 100 or more and 240 or less.

One aspect of the conductive sheet in the technology of the present disclosure is a conductive sheet manufactured by the above-described method for manufacturing a conductive sheet.
In the technology of the present disclosure, one aspect of the conductive sheet includes a base material and a conductive layer provided on the base material. On the surface of the conductive layer, the arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less, and the load length ratio (tp) is a cutting level c. = 50%, 25% or more and 45% or less, and the average interval (Sm) of the unevenness is 5 μm or more and 20 μm or less. The conductive layer includes a polythiophene-based conductive agent and conductive particles. The film thickness a of the conductive layer and the minor axis diameter b of the conductive particles satisfy the following formulas 1 and 2.

a> 100 nm Formula 1
1.5 <b / a <5 Formula 2
In the conductive sheet in the technology of the present disclosure, the conductive layer further includes a binder, a silane coupling compound, and a coupling component that is a reaction product of the silane coupling compound, and the content of the conductive particles is 6 mass% or more and 25 mass% or less, and the silicon element content is preferably 3 mass% or more and 7 mass% or less.

  In the conductive sheet in the technique of the present disclosure, the conductive particles are spherical particles dispersed in the conductive layer, and the short axis diameter b of the conductive particles and the long axis diameter c of the conductive particles are expressed by the following formula 3 It is preferable to satisfy.

c / b <2 Equation 3
In the conductive sheet in the technique of the present disclosure, the conductive particles are at least one selected from the group consisting of silver particles, copper particles, the silver particles whose surface is treated, and the copper particles whose surface is treated. It is preferable that

  In the technology of the present disclosure, one aspect of the touch panel includes a conductive sheet.

  The conductive sheet manufacturing method, the conductive sheet, and the touch panel according to the present disclosure are images that are highly anti-Newton ring property and visible through the conductive sheet in a conductive sheet including a polythiophene-based conductive agent and conductive particles. It is possible to suppress glare.

It is sectional drawing which shows the cross-section of an electroconductive sheet in one Embodiment which actualized the electroconductive sheet of this indication. It is sectional drawing which shows an example of the cross-sectional structure of the electroconductive sheet which has other functional layers other than an electroconductive layer in one Embodiment which actualized the electroconductive sheet of this indication. It is sectional drawing which shows the other example of the cross-section of the electroconductive sheet which has other functional layers other than an electroconductive layer in one Embodiment which actualized the electroconductive sheet of this indication. It is sectional drawing which shows the other example of the cross-section of the electroconductive sheet which has other functional layers other than an electroconductive layer in one Embodiment which actualized the electroconductive sheet of this indication. It is a disassembled perspective view which shows the disassembled perspective structure of the resistive film type touch panel in one Embodiment which actualized the touch panel of this indication.

An embodiment embodying the technology of the present disclosure will be described with reference to FIGS. 1 to 5. First, the electroconductive sheet in this embodiment is demonstrated.
[Configuration of conductive sheet]
As shown in FIG. 1, the conductive sheet 10 includes a base material 11 and a conductive layer 12 provided on the base material 11. The conductive layer 12 includes a polythiophene-based conductive agent and conductive particles. In the conductive sheet 10, the conductive layer 12 may be formed on one side of the base material 11, or may be formed on both sides of the base material 11.

  The shape of the conductive layer 12 is appropriately selected according to the target device to which the conductive sheet 10 is applied. For example, when the conductive sheet 10 is used as an electrode of a resistive film type touch panel, the conductive layer 12 has a layer shape that extends over substantially the entire side surface of the substrate 11. Further, for example, when the conductive sheet 10 is used as an electrode of a capacitive touch panel, the conductive layer 12 has a regular pattern shape suitable for capacitance detection.

The base material 11 and the conductive layer 12 may be colorless and transparent, or may be colored and transparent. When the conductive sheet 10 is used for an electrode of a touch panel, the base material 11 and the conductive layer 12 are preferably colorless and have high transparency. The conductivity of the conductive layer 12 is not particularly limited as long as the conductivity is higher than that of the substrate 11. When the conductive sheet 10 is used for an electrode of a touch panel, the surface resistance of the conductive layer 12 is preferably 10 ⁵ Ω / sq or less, and more preferably 10 ³ Ω / sq or less.

On the surface of the conductive layer 12, the surface roughness shape parameter satisfies the following condition 1, condition 2, and condition 3.
Condition 1: The arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less.

Condition 2: The load length ratio (tp) is 25% or more and 45% or less at the cutting level c = 50%.
Condition 3: As an average interval (Sm) of unevenness, it is 5 μm or more and 20 μm or less.

  When the arithmetic average roughness (Ra) is smaller than 0.08 μm, the effect of suppressing the generation of Newton rings in the conductive sheet 10 cannot be sufficiently obtained. When the arithmetic average roughness (Ra) is larger than 0.18 μm, the transparency required for the conductive sheet 10 cannot be sufficiently obtained.

  When the load length ratio (tp) is smaller than 25%, the tip of the convex portion becomes an excessively acute angle on the surface of the conductive layer 12, and this also causes the generation of Newton rings in the conductive sheet 10. The suppression effect cannot be obtained sufficiently. When the load length ratio (tp) is greater than 45%, the transmitted light from the display is easily scattered on the surface of the conductive layer 12, and thus the glare of the image is deteriorated.

  In the case where the average interval (Sm) of the unevenness is larger than 5 μm, even when the convex portion is damaged by scratching on the surface of the conductive layer, the conductive layer is likely to function correctly by the concave portion that avoids stress, The effects of defects are minimized. If the average interval (Sm) of the unevenness exceeds 20 μm, the stress due to scratching reaches the recesses on the surface of the conductive layer, and it is difficult to suppress the influence of such minute defects.

  The value of the surface roughness shape parameter can be measured with various measuring machines based on JIS B0601-1994. Examples of the various measuring machines include contact-type various roughness meters and optical laser microscopes. In the optical type, a scanning probe microscope or the like can measure the value of a precise roughness parameter. However, since the measurement range is narrower than that of other measuring machines, the measurement needs attention. In such a measuring machine, the measurement range for obtaining the value of the surface roughness shape parameter with high reliability is 100 μm square or more, more desirably 200 μm square or more.

  The irregularities on the surface of the conductive layer 12 may be formed by conductive particles contained in the conductive layer 12, or irregularities are provided on the surface of the substrate 11, so that the surface shape of the conductive layer 12 is the surface shape of the substrate 11. It may be formed by following. Furthermore, an undercoat layer having unevenness may be provided between the base material 11 and the conductive layer 12, and the surface shape of the conductive layer 12 may follow the surface shape of the underlayer. Further, unevenness may be formed on the surface of the conductive layer 12 by post-processing such as a shaping process applied to the surface of the conductive layer 12. In addition, in the structure which obtains specific unevenness | corrugation by mixing | blending adjustment of the electroconductive particle etc. which are contained in the conductive layer 12, the consideration which does not reduce the electroconductivity and optical characteristic of the conductive layer 12 is required. Therefore, as a simpler and more reliable configuration, it is preferable to form the conductive layer 12 with a substantially uniform film thickness on the surface having irregularities so as to follow the irregularities.

  The conductive sheet 10 may have a configuration in which only the conductive layer 12 is provided on the base material 11, or may have a configuration in which the functional layer other than the conductive layer 12 is included in the base material 11. The functional layer other than the conductive layer 12 is, for example, at least one selected from the group consisting of an optical adjustment layer, an anchor layer, a barrier layer, and a hard coat layer. The functional layer other than the conductive layer 12 may have a single layer structure including a single layer, or may have a stacked structure in which a plurality of layers are stacked.

  The optical adjustment layer is a layer that adjusts optical characteristics with respect to visible light in the conductive sheet 10. For example, a refractive index adjustment layer that adjusts the refractive index between layers in a plurality of layers constituting the conductive sheet 10. It is. An anchor layer has a function which improves the adhesiveness between layers in the several layer which comprises the electroconductive sheet 10, for example, is a layer containing reactive substances, such as isocyanate. The barrier layer has a function of suppressing the gas contained in the base material 11 from separating from the base material 11. The hard coat layer is a layer that suppresses the generation of scratches and dirt on the ground covered with the hard coat layer, and is, for example, a layer made of a hard resin.

  As shown in FIG. 2, the functional layer other than the conductive layer 12 may be provided as the back surface layer 13 on the side surface of the base material 11 where the conductive layer 12 is not formed. For example, at least one selected from the group consisting of an optical adjustment layer, a barrier layer, and a hard coat layer may be provided as the back surface layer 13 on the back surface of the substrate 11. Further, if the functional layer other than the conductive layer 12 is provided on the back surface of the base material 11, an anchor layer may be provided between the functional layer and the base material 11.

  As shown in FIG. 3, other functional layers other than the conductive layer 12 may be provided as an undercoat layer 14 on the side surface of the substrate 11 where the conductive layer 12 is formed. For example, at least one selected from the group consisting of an optical adjustment layer, a barrier layer, an anchor layer, and a hard coat layer may be provided as the undercoat layer 14 between the substrate 11 and the conductive layer 12.

  As shown in FIG. 4, other functional layers other than the conductive layer 12 are provided as the back layer 13 on the side surface of the base material 11 where the conductive layer 12 is not formed, and the conductive layer 12 is formed. The undercoat layer 14 may be provided on the side surface. For example, at least one selected from the group consisting of an optical adjustment layer, a barrier layer, and a hard coat layer may be provided as the back surface layer 13 on the back surface of the substrate 11. Further, if the functional layer other than the conductive layer 12 is provided on the back surface of the base material 11, an anchor layer may be provided between the functional layer and the base material 11. In addition, for example, at least one selected from the group consisting of other optical adjustment layers, other barrier layers, other anchor layers, and other hard coat layers is provided between the substrate 11 and the conductive layer 12. May be provided as an undercoat layer 14.

In addition, it is preferable that the transparency of the electroconductive sheet 10 is 70% or more as a total light transmittance (JIS K7105), More preferably, it is 80% or more.
[Substrate 11]
The base material 11 includes a sheet base material formed into a sheet shape such as a glass substrate, a resin film, and a resin plate. The base material 11 may be comprised only from the sheet | seat base material, and may be comprised from the sheet | seat base material and other functional layers other than the conductive layer 12 formed in the surface as needed. .

  The surface of the base material 11 may be a flat surface or an uneven surface subjected to a shaping process such as a sandblasting process or a solvent process. The surface of the substrate 11 may be subjected to surface oxidation treatment such as corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, and ultraviolet irradiation treatment, and adhesion to the conductive layer 12 and other functional layers. Is sufficiently obtained, the surface oxidation treatment may not be performed.

  The resin film forming material and the resin plate forming material are, for example, polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, polypropylene naphthalate, polyethylene, polypropylene, cellophane, diacetylcellulose, triacetylcellulose, cycloolefin Polymer, acetylcellulose butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyimide , Fluororesin, polyamide, (meth) acrylic resin, copolymer of methyl methacrylate and styrene At least one selected from Ranaru group.

  From the viewpoint of increasing transparency, weather resistance, solvent resistance, and cost reduction, the sheet base material is made of polyethylene terephthalate biaxially stretched film, glass substrate, cycloolefin polymer, and polycarbonate. Preferably there is. In particular, from the viewpoint of obtaining high flexibility, the sheet base material is preferably a polyethylene terephthalate biaxially stretched film, a cycloolefin polymer, or a polycarbonate. Further, from the viewpoint of satisfying high flexibility, the thickness of the sheet base material is preferably 10 μm or more and 200 μm or less.

The sheet base material may contain various additives as long as the transparency of the sheet base material is not hindered. Additives contained in the sheet substrate include, for example, antioxidants, heat stabilizers, ultraviolet absorbers, organic particles, inorganic particles, pigments, dyes, fine fibers, antistatic agents, nucleating agents, silane coupling compounds, etc. is there.
[Undercoat layer]
The surface shape of the undercoat layer 14 formed as the base of the conductive layer 12 preferably has irregularities for making the surface shape of the conductive layer 12 uneven. As a method for forming irregularities on the surface of the undercoat layer 14, there are two methods in which particles are mixed in the undercoat layer forming coating solution, and there are two different solubility parameter (SP) values in the undercoat layer forming coating solution. Examples thereof include a method in which the above resin component is contained and one resin component is precipitated by phase separation after the application of the coating liquid for forming the undercoat layer.

  In the method of blending particles into the coating liquid for forming the underlayer, the surface roughness is easily adjusted by the particle diameter of the particles and the amount of particles added. The method of forming an unevenness in the undercoat layer 14 by phase separation containing two or more resin components having different SP values from each other is a method of forming particles in the undercoat layer forming coating solution. Therefore, the position where the irregularities are formed does not depend on the degree of dispersion of the particles, and the stability of the quality is maintained even when the coating is performed for a long time. The method of forming irregularities with particles contained in the coating liquid for forming the undercoat layer and the method of forming irregularities by phase separation can be used in combination.

  The resin component contained in the coating liquid for forming the undercoat layer is, for example, a thermosetting resin or an active energy ray curable resin. Examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, silicon resin, and polysiloxane resin. The active energy ray-curable resin is a monomer having a polymerizable unsaturated group that can be polymerized by irradiation with active energy rays. The active energy ray curable resin may contain a photopolymerization initiator and the like.

  The undercoat layer 14 is preferably a cured product obtained by curing an undercoat layer forming coating solution containing a polyfunctional (meth) acrylic monomer with active energy rays. The undercoat layer 14 can use a monofunctional (meth) acrylic monomer as necessary. Such a cured product is excellent in surface hardness, transparency, scratch resistance, and the like because the base material other than the particles contains a hard acrylic polymer having a crosslinked structure.

  “Polyfunctional” indicates that it has two or more polymerizable unsaturated groups, and “(meth) acrylic monomer” is a compound having at least a (meth) acryloyl group as a polymerizable unsaturated group. “(Meth) acryloyl group” means an acryloyl group or a methacryloyl group.

  Polyfunctional (meth) acrylic monomers are, for example, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) ) Acrylate, neopentyl glycol di (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl Di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, polyethylene glycol (preferably mass average molecular weight 400-600) di (meth) acrylate, modified bis 2 such as enol A di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, or isocyanurate di (meth) acrylate Functional (meth) acrylate; pentaerythritol tri (meth) acrylate, diventaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (Meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate , Polyether tri (meth) acrylate, glycerin propoxy sheetary (meth) acrylate, or trifunctional (meth) acrylate such as tris (acryloxyethyl) isocyanurate; pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) ) Acrylate, ditrimethylolpropane tetra (meth) acrylate, or tetrafunctional (meth) acrylate such as pentaerythritol triacrylate; or dipentaerythritol penta (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipenta Erythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipenta 5-functional or higher (meth) acrylates such as erythritol hexa (meth) acrylate. These polyfunctional (meth) acrylic monomers may be used individually by 1 type, and can also be used in combination of 2 or more type.

  “Monofunctional” means having one polymerizable unsaturated group. Monofunctional (meth) acrylic monomers are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (Meth) acrylate, stearyl (meth) acrylate, allyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, glycerol (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (2-eth Ciethoxy) ethyl (meth) acrylate, butoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2- With methoxypropyl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxy-tripropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, or polypropylene glycol (meth) acrylate is there. These monofunctional (meth) acrylic monomers may be used individually by 1 type, and can also be used in combination of 2 or more type.

  The polyfunctional (meth) acrylic monomer preferably contains a tetrafunctional or higher (preferably pentafunctional or higher) (meth) acrylic monomer and a 2-3 trifunctional (meth) acrylic monomer. A tetrafunctional or higher functional (meth) acrylic monomer contributes to an improvement in hardness, and a 2-3 functional (meth) acrylic monomer contributes to an improvement in flexibility. Therefore, by using these together, the obtained undercoat layer 14 has high hardness and appropriate flexibility. Monofunctional (meth) acrylic monomers contribute to the improvement of flexibility. Moreover, since the viscosity is low, it can also be used for adjusting the viscosity of the coating material.

  Of all polyfunctional (meth) acrylic monomers, the proportion of tetrafunctional or higher (meth) acrylic monomers is preferably 50% by mass or more and less than 95% by mass with respect to the total mass of all (meth) acrylic monomers, and 60% by mass. % To less than 90% by mass is more preferable. In addition, the ratio of the 2-3 (meth) acrylic monomer is preferably 5% by mass or more and less than 50% by mass, and more preferably 10% by mass or more and less than 40% by mass with respect to the total mass of all (meth) acrylic monomers. . The proportion of the monofunctional (meth) acrylic monomer is preferably 1% by mass or more and less than 50% by mass, and more preferably 5% by mass or more and less than 30% by mass with respect to the total mass of all (meth) acrylic monomers.

  Examples of the bifunctional to trifunctional (meth) acrylic monomer include diethylene glycol diacrylate. Examples of the tetrafunctional or higher functional (meth) acrylic monomer include dipentaerythritol hexaacrylate.

  In the method of forming irregularities on the surface of the undercoat layer 14 by phase separation, the resin component contained in the coating liquid for forming the undercoat layer is a mixture of at least two different compositions. This mixture is composed of a polyfunctional (meth) acrylic monomer (a1), a composition (A1) containing a monofunctional (meth) acrylic monomer (a2), a polyfunctional (meth) acrylic monomer (b1) or a monofunctional (meth). A mixture of the composition (B1) containing the acrylic monomer (b2) is preferred. A polyfunctional (meth) acrylic monomer or a monofunctional (meth) acrylic monomer may be used alone or in combination of two or more. In addition, a polyfunctional (meth) acrylic monomer or a monofunctional (meth) acrylic monomer may be polymerized before mixing two or more different compositions. The polyfunctional (meth) acrylic monomer is preferably pentaerythritol triacrylate or dipentaerythritol hexaacrylate, and the monofunctional monomer is preferably cyclohexyl methacrylate, n-butyl methacrylate, methyl methacrylate, or isobornyl methacrylate.

  In the method of forming irregularities with particles on the surface of the undercoat layer 14, the particles contained in the coating liquid for forming the undercoat layer may be inorganic particles or organic particles. As the inorganic particles, those having high hardness are preferable. For example, inorganic particles such as silicon dioxide particles (silica), titanium dioxide particles, zirconium oxide particles, aluminum oxide particles, tin dioxide particles, antimony pentoxide particles, or antimony trioxide particles. It is at least one selected from the group consisting of oxide particles.

  The inorganic particles may be reactive inorganic oxide particles obtained by treating inorganic oxide particles with a silane coupling compound. According to the treatment with the silane coupling compound, the bonding force between the acrylic polymer and the inorganic particles is increased. As a result, the surface hardness and scratch resistance of the undercoat layer 14 are increased, and the dispersibility of the inorganic oxide particles is also increased.

  Examples of the silane coupling compound include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxy. It is at least one selected from the group consisting of silane, γ-aminopropyltriethoxysilane, or γ-aminopropyltriethoxyaluminum. As a silane coupling compound, these 1 type may be used independently and 2 or more types may be used together.

The treatment amount of the silane coupling compound is preferably 0.1 to 20 parts by mass and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the inorganic oxide particles.
The organic particles are, for example, resin particles such as acrylic resin, polystyrene, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, cellulose acetate, polycarbonate, and polyamide.

  The organic particles may be reactive resin particles obtained by treating resin particles with a silane coupling compound. According to the treatment with the silane coupling compound, the bonding force between the acrylic polymer and the organic particles is increased. As a result, the surface hardness and scratch resistance of the undercoat layer 14 are increased, and the dispersibility of the resin particles is also increased.

The silane coupling compound and the treatment amount thereof are the same as the silane coupling compound and the treatment amount exemplified in the reactive inorganic oxide particles.
The particle diameter of the particles contained in the undercoat layer 14 is preferably 5 nm or more and 100 nm or less, more preferably 10 nm or more and 50 nm or less in order to maintain the transparency (haze) of the coating film. And when forming the unevenness | corrugation of the conductive layer 12 by addition of the particle | grains to the undercoat layer 14, it is preferable to use the larger particle | grains or the aggregated particle which the primary particle aggregated. Specifically, the preferred particle size is 100 nm or more and 10 μm or less, more preferably 200 nm or more and 5 μm or less. Here, in the case of aggregated particles, the aggregated diameter is defined as the particle diameter. Among these, aggregated particles of silica of 500 nm or more and 3 μm or less are suitable for forming irregularities on the surface of the underlayer.

  The primary particle diameter of the particles contained in the undercoat layer 14 is determined by observing the enlarged image. For example, using a transmission electron microscope, the maximum length of the image particle image of the coating layer (Dmax: maximum length at two points on the contour of the particle image) and the maximum length vertical length (DV-max: maximum length) The shortest length between the two straight lines when the particle image is sandwiched between the two straight lines parallel to the surface, and the geometric mean value (Dmax × DV-max) 1/2 is taken as the particle diameter. To do. The particle diameter is measured for 100 particles by this method, and the arithmetic average value is defined as the average primary particle diameter. The particle size of aggregated particles can be measured with the most accurate value when the particle dispersion is measured by dynamic light scattering or laser diffraction. However, the state of aggregation can also be grasped by observing the enlarged image of the coating layer. Is possible.

  The compounding amount of the particles in the undercoat layer 14 is 1% by mass or more and 10% by mass or less with respect to the solid content of the coating solution for the undercoat layer, that is, the undercoat layer 14. The solid content of the coating liquid for the undercoat layer indicates the total of all components constituting the coating liquid for the undercoat layer when the solvent is not included, and the total content of all components excluding the solvent when the solvent is included. Indicates total. As the blending amount of such particles increases, the surface roughness tends to increase, and a desired surface roughness is easily obtained if the amount is in the range of 1% by mass or more and 10% by mass or less. In particular, when it is 1% by mass or more, the anti-Newton ring property that suppresses the formation of Newton rings is enhanced, and when it is 10% by mass or less, a sufficient amount of polyfunctional (meth) acrylic monomer can be blended. A hardness of 14 is good.

  The coating liquid for forming the undercoat layer preferably contains a photopolymerization initiator together with the polyfunctional (meth) acrylic monomer and particles in order to promote curing. Known photopolymerization initiators can be used such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2- Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4 -(Methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, or p-phenylbenzopheno 4,4′-diethylaminobenzophenone, propiophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2- Examples include chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, and p-dimethylamine benzoate. These photoinitiators may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the solid content of the coating liquid for the undercoat layer, the blending amount of the photopolymerization initiator includes the solvent with respect to the mass of all components constituting the coating liquid for the undercoat layer when the solvent is not included. In the case, 0.5 to 10% by mass is preferable and 2 to 8% by mass is more preferable with respect to the mass of all components excluding the solvent. When it is 0.5% by mass or more, poor curing hardly occurs. Even if it mixes exceeding 10 mass%, the hardening acceleration | stimulation effect corresponding to a compounding quantity is not acquired, but cost also becomes high. Moreover, it may remain in the cured product and cause yellowing or bleeding out.

  In addition to the photopolymerization initiator, a photosensitizer can be further contained. Examples of the photosensitizer include n-butylamine, triethylamine, or tri-n-butylphosphine.

  The coating liquid for forming the undercoat layer may contain a solvent. Solvents are, for example, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, toluene, n-hexane, n-butyl alcohol, methyl isobutyl ketone, methyl butyl ketone, ethyl butyl ketone, cyclohexanone, ethyl acetate, butyl acetate, propylene glycol monomethyl ether Acetate, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, N-methyl-2-pyrrolidone and the like. These may be used alone or in combination of two or more.

  In particular, since it is possible to reduce coating unevenness, it is preferable to use two or more solvents having different evaporation rates in combination. For example, it is preferable to use a mixture of at least two solvents selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol monomethyl ether.

The coating amount of the coating liquid for the undercoat layer is set according to the thickness of the undercoat layer 14. The thickness of the undercoat layer 14 is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.2 μm or more and 8 μm or less.
[Polythiophene-based conductive agent]
The polythiophene-based conductive agent constituting the conductive layer 12 is a polythiophene having a π-conjugated main chain in which carbon-to-carbon double bonds and carbon-to-carbon single bonds are alternately arranged to exhibit conductivity in the main chain. System compounds. A polythiophene-based compound is a conductive agent exhibiting high transparency while exhibiting electrical conductivity while hardly exhibiting light absorption in the visible light region.

  The polythiophene compound is selected from the group consisting of a polymer of 3-hexylthiophene, a polymer of 3,4-ethylenedioxythiophene (hereinafter referred to as EDOT) (hereinafter referred to as PEDOT), and derivatives thereof. It is preferable that it is at least one. The polythiophene compound may be composed of one type of polymer or a mixture of two or more types of polymers. The polythiophene compound is not limited to a polymer of 3-hexylthiophene and PEDOT, but may be a polythiophene derivative other than these. The kind and composition of the polythiophene compound in the polythiophene conductive agent are appropriately selected according to the use of the conductive sheet 10 and the like.

  The polymer derivative of 3-hexylthiophene is, for example, a self-doped polythiophene having a sulfonic acid group in the main chain. The derivative of PEDOT is, for example, an organic solvent dispersion type PEDOT in which a flexible polymer such as polyethylene glycol and EDOT are copolymerized.

  As a method for forming the conductive layer 12 including the polythiophene-based conductive agent, coating or printing on the base material 11 is used. The raw material used for coating and the raw material used for printing are a liquid containing a polythiophene-based conductive agent, that is, a coating liquid.

  The coating liquid for forming the conductive layer preferably contains a dopant that increases the conductivity of the conductive layer 12 and a dispersion medium that increases the dispersibility of the polythiophene compound. Polystyrene sulfonic acid (hereinafter referred to as PSS) and polyvinyl sulfonic acid (hereinafter referred to as PVS) have a function as a dispersion medium that disperses PEDOT in water in water in addition to the function as a dopant. In the conductive layer forming coating liquid and the conductive layer 12 formed from the conductive layer forming coating liquid, the polythiophene-based conductive agent may include a polythiophene-based compound and a dopant that increases the conductivity thereof.

  The coating liquid containing PEDOT may further contain a high-boiling solvent that increases the conductivity of the conductive layer 12 as a secondary dopant. If the secondary dopant is included in the conductive layer 12, the conductivity of the conductive layer 12 is further increased. The secondary dopant is, for example, at least one selected from the group consisting of polyethylene glycol, methylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. The blending amount of the secondary dopant in the coating liquid for forming the conductive layer is preferably 1% by mass or more and 10% by mass or less, and preferably 2% by mass or more, with respect to the coating liquid for forming the conductive layer. 8 mass% or less is more preferable. In the configuration in which the addition amount of the secondary dopant is lower than 1% by mass, the effect as the secondary dopant cannot be sufficiently obtained. Moreover, in the structure where the addition amount of the secondary dopant is higher than 10% by mass, the amount of the secondary dopant which is a high boiling point solvent becomes excessive in the conductive layer 12, and the secondary dopant may bleed (elution). is there.

  For adjusting the coating liquid containing PEDOT, for example, a method of polymerizing EDOT in the presence of PSS to obtain PEDOT-PSS as an aqueous dispersion is suitable. Also suitable is a method of polymerizing EDOT in the presence of PVS to obtain PEDOT-PVS as an aqueous dispersion. In particular, the method of obtaining PEDOT-PSS is more preferable in that high conductivity can be obtained.

From the viewpoint of increasing the conductivity of the conductive layer 12, the blending amount of the polythiophene-based conductive agent in the conductive layer 12 is preferably as high as possible. The blending amount of the polythiophene-based conductive agent in the conductive layer 12 is 10 mass relative to the mass component of the conductive layer 12 from the viewpoint of increasing the conductivity of the conductive layer 12 and increasing the ease of coating of the conductive layer 12. % Or more and 90% by mass or less, more preferably 30% by mass or more and 70% by mass or less.
[binder]
The binder constituting the conductive layer 12 is a resin that fixes the state of the polythiophene-based conductive agent at the conductive layer 12. From the viewpoint of increasing the conductivity of the conductive layer 12, the blending amount of the polythiophene-based conductive agent in the conductive layer 12 is preferably as high as possible. On the other hand, the higher the blending amount of the polythiophene-based conductive agent in the conductive layer 12, the higher the degree of decrease in conductivity due to various stresses such as temperature, humidity, solvent, and abrasion. The binder has a function of fixing the state of the polythiophene-based conductive agent with the conductive layer 12 and suppressing a decrease in conductivity due to such various stresses.

  The binder is, for example, at least one selected from the group consisting of acrylic resin, styrene resin, polyester resin, alkyd resin, urethane resin, amide resin, modified resins thereof, and copolymer resins thereof. The binder may be one type of resin or a mixture of two or more types of resins different from each other. The binder is appropriately selected depending on the configuration of the polythiophene-based conductive agent and the configuration of the substrate 11. From the viewpoint of obtaining low hygroscopicity, high acid resistance, and excellent coating suitability, the binder is preferably a polyester resin.

  The binder may include a monomer or oligomer as a raw material thereof, and may further include a polymerization initiator, a crosslinking agent, and the like. The coating liquid for forming the conductive layer 12 contains at least a monomer or an oligomer as a raw material for the binder, and contains a polymerization initiator.

  The raw material of the binder is, for example, polyester (meth) acrylate, urethane (meth) acrylate, or epoxy (meth) acrylate. Hereinafter, monofunctional means that it has one polymerizable unsaturated group, bifunctional means that it has two polymerizable unsaturated groups, and trifunctional means that it has three polymerizable unsaturated groups. Indicates.

  When the binder is a radical polymer, the raw material of the binder is monofunctional, for example, ethyl carbitol (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, nonylphenol ethylene oxide modified (meth) acrylate, ethoxydiethylene glycol acrylate, It is at least one selected from the group consisting of acryloylmorpholine, isobornyl (meth) acrylate, and N-vinylpyrrolidone.

  When the binder is a radical polymer, the raw material of the binder is bifunctional, for example, hexanediol di (meth) acrylate, hexanediol ethylene oxide modified diacrylate, neopentyl glycol polyethylene oxide modified di (meth) acrylate, tetraethylene Selected from the group consisting of glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate, polyethylene glycol di (meth) acrylate At least one.

  When the binder is a radical polymer, the material of the binder is trifunctional or higher, for example, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, glycerin propoxy sheetary (meth) acrylate , Dipentaerythritol hexaacrylate, and ditrimethylolpropane tetraacrylate.

  When the binder is a cationic polymer, the raw material of the binder is, for example, at least one selected from the group consisting of epoxy compounds such as glycidyl ether compounds and alicyclic epoxy compounds, oxetane compounds, and vinyl ether compounds. It is not limited to.

The polymerization initiator is, for example, an azo compound such as azobisisobutyronitrile, an organic peroxide such as benzoyl peroxide, or a dihalogen compound, and other known ones may be used. From the viewpoint of increasing the conductivity of the polythiophene-based conductive agent, the blending amount of the binder in the conductive layer 12 is preferably small. In addition, when the compounding quantity of a binder is too small, the suitability with respect to coating of a coating liquid will become low. From these viewpoints, when the polythiophene-based conductive agent is 100 parts by mass, the blending amount of the binder is preferably 500 parts by mass or less, and more preferably 300 parts by mass or less. Moreover, 10 mass parts or more are preferable and, as for the compounding quantity of a binder, 20 mass parts or more are more preferable.
[Conductive particles]
The shape and size of the conductive particles constituting the conductive layer 12 are in a range satisfying the following formulas 1 and 2 in the film thickness a of the conductive layer 12 and the minor axis diameter b of the conductive particles. In particular, it is not limited. The shape of the electric particles may be spherical, flat, flake, linear, or indefinite. Furthermore, from the viewpoint of little influence on the external appearance of the conductive layer 12 and improved scratch resistance, the shape of the conductive particles is as follows for the short axis diameter b of the conductive particles and the long axis diameter c of the conductive particles. It is preferable to satisfy Formula 3, a spherical shape having a shape with less unevenness on the particle surface is more preferable, and a true spherical shape is more preferable.

a> 100 nm Formula 1
1.5 <b / a <5 Formula 2
c / b <2 Equation 3
When b / a is smaller than 1.5, in the process of forming the conductive layer 12, the conductive particles are likely to aggregate, and there is a high possibility that the conductive particles are buried deep from the surface of the conductive layer 12. . On the other hand, when b / a is larger than 5, the conductive particles easily fall off from the conductive layer 12, and it is difficult to obtain the effect of the addition of the conductive particles.

  The film thickness a of the conductive layer is an average value of film thicknesses obtained from different portions in the conductive layer 12, and is obtained from an observation image such as a scanning electron microscope or an optical microscope. The film thickness “a” of the conductive layer is, for example, an average value obtained from the film thicknesses of 20 different places in the conductive layer 12. The minor axis diameter b of the conductive particles is an average value of primary particle diameters in the minor axis direction obtained from each of the plurality of conductive particles, and the surface observation image of the conductive layer 12 and the cross-sectional observation image of the conductive layer 12 are obtained. Obtained from. The short axis diameter b of the conductive particles is obtained by, for example, obtaining the short axis diameters of 100 different conductive particles in the portion used for calculating the film thickness a of the conductive layer, and the average value of the short axis diameters. As required.

  When the conductive sheet 10 is used as an electrode of a resistive film type touch panel, the unevenness of the surface shape of the conductive particles can scratch the surface of the counter electrode facing the conductive layer 12. The conductive particles having a spherical shape and the conductive particles having a true spherical shape suppress such a possibility. The conductive particles having a linear shape may increase the variation in conductivity in the conductive layer 12, but the conductive particles having a spherical shape and the conductive particles having a true spherical shape also suppress such a possibility. .

  The material for forming the conductive particles is not particularly limited within the range of the material exhibiting conductivity. The material for forming the conductive particles is made of, for example, a metal such as gold, silver, or copper, a metal oxide such as ITO or ATO, a metal compound other than the metal oxide, an organic conductive polymer such as polyaniline or polypyrrole, or carbon. It is at least one selected from the group. From the viewpoint of increasing conductivity, scratch resistance, and corrosion resistance, the material for forming the conductive particles is preferably a metal such as gold, silver, or copper.

  One conductive particle may be formed from one type of forming material, or may be formed from two or more types of forming materials different from each other. One conductive particle may be, for example, a silver-coated copper particle in which the surface of the copper particle is covered with silver. Further, the conductive particles may be particles that have been subjected to a surface treatment other than coating in order to improve oxidation resistance and corrosion resistance. Silver is preferable as a surface material from the viewpoint of increasing conductivity, scratch resistance, and corrosion resistance, and copper is preferable as a bulk material from the viewpoint of reducing the cost of the forming material.

  The conductive particles contained in the conductive layer 12 may be one type of conductive particles, or may be a mixture of two or more types of conductive particles formed from different forming materials. The conductive particles contained in the conductive layer 12 may be, for example, a mixture of silver-coated copper particles and silver particles, or a mixture of silver-coated copper particles and copper particles.

  The distribution of the conductive particles contained in the conductive layer 12 may be configured such that the conductive particles are biased to a specific portion where the conductive layer 12 and another conductive member are in contact with each other, or the entire conductive layer 12 is conductive. The particles may be configured to be uniformly dispersed, or the conductive particles may be configured to be uniformly dispersed over the entire surface of the conductive layer 12. When the conductive layer 12 containing conductive particles comes into contact with another conductive member facing the conductive layer 12, a part of the surface of the conductive layer 12 rubs against the surface of the other conductive member. If the conductive particles are dispersed throughout the surface of the conductive layer 12, the conductive particles and other conductive members are in point contact, and the conduction between the conductive layer 12 and the other conductive members during the above-described rubbing is particularly Stabilize. If the conductive particles satisfy the above formulas 1 and 2, the protection of the conductive layer 12 and the stability of conduction are enhanced, and the conductive particles are uniformly dispersed on the surface of the conductive layer 12. If it is a structure, the effect is remarkable.

  Typical methods for producing silver particles suitable as the conductive particles are, for example, an atomizing method and a wet reduction method. The wet reduction method is preferable from the viewpoints of easily obtaining spherical conductive particles and easily dispersing the conductive particles uniformly. Silver particles suitable as the conductive particles are exemplified in Japanese Patent Application Laid-Open No. 2004-100013, Japanese Patent Application Laid-Open No. 2005-093380, and the like, and described in Japanese Patent Application Laid-Open No. 11-189812. It is also possible to include other metal components as long as they are not greatly reduced.

  In order to suppress excessive aggregation of the conductive particles, a protective colloid that protects the conductive particles may be used in the production of the conductive particles, or a stabilizer that stabilizes the dispersed state of the conductive particles. May be used. As the protective colloid and stabilizer, carboxylic acid compounds such as gelatin, gum arabic, polyvinyl alcohol, ascorbic acid, amine compounds, thiol compounds, and the like are used. In addition, when the polythiophene-based conductive agent coexists, the amine compound and the thiol compound are strongly bonded to the surface of the silver particle, and an insulating coating layer is formed on the surface of the silver particle, Since it is easy to cause aggregation, it is preferably used as a combination of conductive particles other than silver particles and conductive particles other than particles having silver on the surface.

  The conductive particles contained in the conductive layer 12 form not only irregularities on the surface of the conductive layer 12, so if the amount of the conductive particles is excessive, optical characteristics such as transmittance required for the conductive layer 12. Excessive conductive particles are lowered. The range of the blending amount of the conductive particles in which the surface protection of the conductive layer 12 and the stability of conduction are enhanced by the conductive particles and the optical properties required for the conductive layer 12 are maintained are as follows (a ) And (b). That is, the range of the blending amount of the conductive particles that enhances the sensitivity to pressing and writing and the resistance to repeated pressing and writing is at least one of the following (a) and (b).

(A) In the coating liquid, when the mass part of the polythiophene-based conductive agent is 100, the mass part of the conductive particles is 20 or more and 100 or less.
(B) In the conductive layer 12, the content rate which is the mass of the electroconductive particle with respect to the mass of the conductive layer 12 is 6 mass% or more and 25 mass% or less.
[Coupling ingredients]
The coupling component constituting the conductive layer 12 is composed of a silane coupling compound and a reaction product of the silane coupling compound. The reactant of the silane coupling compound is a product obtained by dehydration condensation of the silane coupling compound. The coupling component has a function of crosslinking the binders. The coupling component enhances the ease of application of the conductive layer 12 and the hardness of the conductive layer 12 by crosslinking, and also enhances the adhesion between the conductive layer 12 and the base thereof by crosslinking.

  For example, when the conductive layer 12 is formed on the base material 11 containing a large amount of silicon component or the base material 11 having a hard coat layer containing silicon component on the surface, the coupling component is formed between the conductive layer 12 and its underlying layer. Increase adhesion between. In particular, when a PET film is used as the substrate 11, an adhesive layer containing a silicon component is formed on the surface of the PET film, and the conductive layer 12 is formed on the adhesive layer, the coupling component is The adhesion between the substrate 11 is increased.

  The silane coupling compound is, for example, at least one selected from the group consisting of epoxy-based, vinyl-based, methacrylic-based, acrylic-based, and sulfide-based, and among these, the adhesion between the conductive layer 12 and the base thereof. From the viewpoint of increasing the viscosity, an epoxy-based silane coupling compound is preferable.

  From the viewpoint of increasing the conductivity by the polythiophene-based conductive agent, the amount of the coupling component contained in the conductive layer 12 is preferably as small as possible. On the other hand, when the blending amount of the coupling component is too small, the ease of application of the conductive layer 12 and the hardness of the conductive layer 12 are reduced, and the adhesion between the conductive layer 12 and the base thereof is also reduced. descend. A cup that improves the ease of application of the conductive layer 12, the protective property of the conductive layer 12, and the adhesion between the conductive layer 12 and the base thereof, and the conductivity required for the conductive layer 12. The range of the ring component is preferably at least one of the following (c) and (d). That is, it is preferable that the range of the amount of the coupling component that enhances the sensitivity to pressing and writing and the resistance to repeated pressing and writing is at least one of the following (c) and (d).

(C) In a coating liquid, when the mass part of a polythiophene type | system | group electrically conductive agent is 100, the mass part of a silane coupling compound is 100 or more and 240 or less.
(D) In the conductive layer 12, the content rate of the silicon element with respect to the mass of the conductive layer 12 is 3 mass% or more and 7 mass% or less.
[Additive]
The coating liquid for forming the conductive layer for forming the conductive layer 12 is added within a range that does not significantly reduce the conductivity, in addition to the polythiophene-based conductive agent, binder, conductive particles, and coupling component. Agents may be included. The conductive layer 12 formed from the coating liquid for forming the conductive layer may also contain such an additive.

  Additives include additives such as antioxidants, heat stabilizers, UV absorbers, metal corrosion inhibitors, pH adjusters, organic particles, inorganic particles, pigments, dyes, fine fibers, antistatic agents, nucleating agents, and the like , At least one selected from the group consisting of coating aids such as wetting agents and antifoaming agents.

  The coating aid has a function of suppressing the occurrence of defects such as holes in the conductive layer 12. Examples of the coating aid include silicone-based, long-chain alkyl-based, and fluorine-based surfactants. From the viewpoint of improving the adhesion between the conductive layer 12 and the base material 11, the blending amount of the coating aid is such that the contact angle of the coating liquid to the base is 50 ° or more and 100 ° or less, more preferably 60 ° or more and 90. A configuration in which the angle is set to ° or less is preferable. The surface active function of the coating aid may be possessed by a binder or a silane coupling compound.

The pH adjuster has a function of suppressing deterioration of the polythiophene-based conductive agent due to pH fluctuation. For example, when the polythiophene-based conductive agent is PEDOT-PSS, the oxidation reaction of PEDOT and the hydrolysis reaction of PSS can be suppressed by adding a pH adjusting agent. The pH adjuster is, for example, at least one selected from the group consisting of an acetic acid-sodium acetate mixture, a phosphoric acid-sodium phosphate mixture, a citric acid-sodium citrate mixture, and a glycine-hydrochloric acid mixture.
[Method for Producing Conductive Sheet 10]
In the method for producing the conductive sheet 10, first, coating or printing using the coating liquid for the undercoat layer is applied to the side surface of the base material 11 on which the undercoat layer 14 is to be formed. Is applied to form an undercoat layer. Next, coating using a coating liquid for forming a conductive layer or printing is performed on the surface of the undercoat layer to form a coating film. Next, the conductive layer 12 is formed by curing the coating film formed on the substrate 11.

  Since the conductivity of the polythiophene-based conductive agent is high under acidic conditions, the pH of the coating liquid for forming the conductive layer is preferably 1 or more and 6 or less. When the pH of the coating solution is high, for example, an acidic solution such as sulfuric acid or hydrochloric acid may be added to the coating solution, or a pH adjuster may be added to the coating solution.

  Examples of the coating method include a method using a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a micro gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater, and the like. When there is little coating liquid used for coating, it is preferable to use a micro gravure coater. Examples of the printing method include screen printing, offset printing, flexographic printing, gravure offset printing, and inkjet printing.

  Examples of the curing method of the coating film include drying of the coating film by a heated air dryer or a vacuum dryer. When the binder contained in the coating liquid is a thermosetting resin, the coating film may be heated using a heating furnace or an infrared lamp when the coating film is cured. In addition, when the binder contained in the coating liquid is an active energy ray-curable resin, the coating film may be irradiated with active energy rays when the coating film is cured.

  The active energy rays are, for example, ultraviolet rays or electron beams, and are preferably ultraviolet rays from the viewpoint of high versatility. As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, an electrodeless ultraviolet lamp, or the like is used. As the electron beam, for example, an electron beam emitted from various electron beam accelerators such as a Cockloftwald type, a bandecraft type, a resonant transformation type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type is used. Curing by irradiation with active energy rays is preferably performed in the presence of an inert gas such as nitrogen in order to avoid curing inhibition by oxygen in the atmosphere, and nitrogen gas can be suitably used from the viewpoint of cost. In addition, the active energy ray irradiation process may be performed in two stages, a preliminary curing process and a main curing process.

  Even in the configuration in which other functional layers other than the conductive layer 12 are provided, the formation of the other functional layers is performed by, for example, coating using a coating liquid for the functional layer or printing. A functional layer other than the conductive layer 12 is formed by curing the formed coating film.

The patterning on the conductive layer 12 may be a method of forming a coating film only on the surface of the substrate 11 where the conductive layer 12 is to be formed, or the conductive layer 12 is further etched. It may be a method. For example, a gravure coater or various types of printing is used as a method of forming a coating film only at a portion where the conductive layer 12 is to be formed. For the etching of the conductive layer 12, for example, wet etching or dry etching including ablation by laser light is used.
[Touch panel]
The touch panel including the conductive sheet 10 may be a resistance film type touch panel using the conductive layer 12 as an electrode, or may be a resistance film type touch panel using the conductive layer 12 as a shield layer. The touch panel provided with the conductive sheet 10 may be a capacitive touch panel using the conductive layer 12 as an electrode, or may be a capacitive touch panel using the conductive layer 12 as a shield layer. The electrode carried by the conductive layer 12 may be the upper electrode of the touch panel, the lower electrode of the touch panel, or both the upper electrode and the lower electrode.

  In addition, in the touch panel which has electrodes other than the conductive layer 12, the electrodes other than the conductive layer 12 may be a metal oxide compound layer such as ITO or ATO, or silver or copper having a mesh shape. The metal layer may be an electrode formed by coating a nanowire material. Moreover, electrodes other than the conductive layer 12 may be comprised from carbon-type compounds, such as carbon nanowire which has electroconductivity, and a graphene.

Hereinafter, an example in which the conductive layer 12 is used for the upper electrode of a resistive touch panel that is an example of a touch panel will be described.
As shown in FIG. 5, the resistive touch panel 20 is a laminated body of the conductive sheet 10 and the ITO glass 21. The conductive layer 12 of the conductive sheet 10 faces the ITO glass 21, and a dot spacer (not shown) is arranged between the conductive layer 12 and the ITO glass 21 so as to leave a predetermined gap. The conductive layer 12 of the conductive sheet 10 functions as an upper electrode of the resistive film type touch panel 20, and the ITO glass 21 functions as a lower electrode of the resistive film type touch panel 20.

  The side surface facing the ITO glass 21 in the conductive layer 12 has two conductive layer extraction electrodes P1 facing each other. The two conductive layer extraction electrodes P <b> 1 have a linear shape along one side constituting the edge of the conductive layer 12. One extraction electrode P <b> 1 is formed in the vicinity of one side that forms the edge of the conductive layer 12, and the other extraction electrode P <b> 1 is formed in the vicinity of the other side that forms the edge of the conductive layer 12. The two conductive layer extraction electrodes P1 are covered with an insulating adhesive G1 so that the extraction electrode P1 and the ITO glass 21 do not directly contact each other. The lead electrodes P1 for the two conductive layers are separately connected to an external detection circuit through an anisotropic conductive adhesive or anisotropic conductive paste. The material for forming the extraction electrode P <b> 1 is not particularly limited as long as it is in a state where more stable conduction than the conductive layer 12 can be ensured. The extraction electrode P1 is, for example, silver, copper, aluminum, molybdenum, etc., which are highly conductive metals.

  The side surface of the ITO glass 21 that faces the conductive layer 12 has two lead electrodes P2 for ITO glass that face each other. The two lead electrodes P <b> 2 for ITO glass have a linear shape along one side constituting the edge of the ITO glass 21. One extraction electrode P <b> 2 is formed in the vicinity of one side constituting the edge of the ITO glass 21, and the other extraction electrode P <b> 2 is formed in the vicinity of the other side constituting the edge of the ITO glass 21. The two extraction electrodes P2 for ITO glass are located along the direction orthogonal to the extraction electrode P1 for the conductive layer. The two extraction electrodes P2 for ITO glass are covered with an insulating adhesive G2 so that the extraction electrode P2 and the conductive layer 12 do not directly contact each other. The two lead electrodes P2 for ITO glass are separately connected to an external detection circuit through an anisotropic conductive adhesive or anisotropic conductive paste. The material for forming the extraction electrode P2 is not particularly limited as long as it is in a state where more stable conduction than the ITO glass 21 can be secured. The extraction electrode P2 is, for example, silver, copper, aluminum, molybdenum, etc., which are highly conductive metals.

  The distance between the conductive layer 12 and the ITO glass 21 is adjusted by the thickness of the adhesive materials G1 and G2. The adhesive materials G1 and G2 may be composed of an adhesive layer, or may be composed of adhesive layers on both surfaces of the base material of the adhesive materials G1 and G2. The forming materials of the adhesive materials G1 and G2 are, for example, natural rubber-based adhesives, synthetic rubber-based adhesives, acrylic-based adhesives, urethane-based adhesives, silicone-based adhesives, etc., solvent-based, emulsion-based, water-based, etc. Either may be sufficient. Of these, solvent-based acrylic pressure-sensitive adhesives are particularly preferred from the viewpoints of increasing transparency, weather resistance, durability, and cost reduction. Furthermore, from the viewpoint of obtaining high adhesiveness, the forming material of the adhesive materials G1 and G2 is particularly preferably a polymer containing ethylhexyl acrylate or butyl acrylate as a monomer unit. Moreover, an auxiliary agent may be added to the pressure-sensitive adhesive as necessary. Examples of auxiliary agents include ultraviolet absorbers, thickeners, pH adjusters, tackifiers, binder components, coupling components, adhesive particles, antifoaming agents, antiseptic / antifungal agents, and the like.

The manufacturing method of the electroconductive sheet in this indication, the electroconductive sheet, and the example which is an example of a touch panel are described below. In addition, "%" shown in an Example shows the mass% unless there is particular notice.
[Example 1]
[Preparation of conductive sheet]
As the substrate 11, a biaxially stretched polyethylene terephthalate film (trade name: Lumirror U48, manufactured by Toray Industries, Inc., thickness 188 μm) having easy-adhesion layers on both sides was used. On one side of the biaxially stretched polyethylene terephthalate film, a hard coat agent (trade name: Murasaki UV-7600B, manufactured by Nippon Synthetic Chemical Co., Ltd.) was applied with a bar coater so that the film thickness after drying was 5 μm. Thereafter, the coating film was dried with hot air at 80 ° C. Next, a hard coat layer for the back surface was formed by irradiating the coating film with 300 mJ / cm ² of ultraviolet light in a nitrogen atmosphere with a high-pressure mercury lamp ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd.).

Next, a 6: 4 mixture of AG hard coat agent (trade name: Forse Seed No. 330 M, manufactured by China Paint Co., Ltd.) and clear hard coat agent (trade name: Forse Seed No. 300C, manufactured by China Paint Co., Ltd.) The coating liquid for forming the undercoat layer of Example 1 was prepared. On the side of the base material opposite to the side on which the hard coat layer for the back surface is formed, the coating liquid for forming the undercoat layer is applied with a bar coater so that the film thickness after drying is 2.5 μm. Thereafter, the coating film was dried by heating in an atmosphere of 80 ° C. for 60 seconds. In addition, an undercoat layer was formed by irradiating the coating film with 300 mJ / cm ² of ultraviolet light in a nitrogen atmosphere with a high-pressure mercury lamp ultraviolet irradiation machine to cure the coating film.

  As a polythiophene-based conductive material, PEDOT-PSS obtained by polymerizing 3,4-ethylenedioxythiophene in the presence of polystyrene sulfonic acid is used, and a polyester diameter resin (trade name: pesresin A-645GH, acrylic-modified polyester 30) is used as a binder. % Aqueous dispersion, manufactured by Takamatsu Yushi Co., Ltd.). Further, 3-glycidoxypropyltriethoxysilane (trade name: KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.) is used as the silane coupling compound, and wet copper powder (trade name: 1030Y, Mitsui Metals) as the conductive particles. Mining Co., Ltd.) was used.

  Then, a 1% solid dispersion of PEDOT-PSS, a 1% dispersion of a polyester resin diluted with water, a 1% solution of 3-glycidoxypropyltriethoxysilane diluted with methanol, and water 1% dispersion of wet copper powder dispersed in an equal volume of methanol and methanol, and a surfactant diluted with an equal volume of water and methanol (trade name: Surflon S-386, manufactured by AGC Seimi Chemical Co., Ltd.) , 100% active ingredient) and 1% solution. At this time, conductive polymer: binder resin: silane coupling compound: conductive particles: surfactant = 100: 100: 110: 30: 10 were mixed to obtain a mixed solution A. 3% of dimethyl sulfoxide (Kanto Kagaku Co., Ltd., reagent) was mix | blended with this liquid mixture A, and the coating liquid for conductive layer formation was obtained.

After corona treatment is applied to the surface of the undercoat layer, a coating solution for forming a conductive layer is applied with a bar coater, and the coating film is dried at 100 ° C. to form a conductive layer. The conductive sheet in Example 1 was obtained. In addition, the film thickness of the conductive layer was adjusted by the coating amount of the coating liquid for forming the conductive layer so that the surface resistance of the conductive layer was about 400 Ω / sq. At this time, the surface resistance was measured by a method based on JIS K7194 using Loresta EP: MCP-T360 manufactured by Mitsubishi Chemical Analytech Co., Ltd.
[Production of touch panel]
The obtained conductive sheet was cut out to 70 mm × 100 mm to prepare ITO glass with a dot spacer of the same size (surface resistance of about 400Ω / sq). Silver paste (trade name: Doutite FA-401CA, manufactured by Fujikura Kasei Co., Ltd.) was used as a material for forming the extraction electrodes P1 and P2. And the pattern corresponding to the extraction electrode P1 was formed in the conductive surface of the conductive layer with the silver paste, and the pattern corresponding to the extraction electrode P2 was formed in the conductive surface of the ITO glass with the silver paste. Next, the silver paste pattern was baked by heating at 140 ° C. for 15 minutes to form extraction electrodes P1 and P2. Furthermore, a conductive copper foil tape is bonded to each of the extraction electrodes P1 and P2 to form a terminal to which the detection circuit is connected, and an upper electrode in the resistive touch panel and a lower electrode in the resistive touch panel are connected. Obtained. Subsequently, an insulating adhesive tape having a thickness of 80 μm is used as the adhesive materials G1 and G2, and at the position where the conductive surface of the conductive layer and the conductive surface of the ITO glass face each other, the peripheral portion of the upper electrode and the lower electrode The peripheral part was bonded together to obtain an evaluation resistive touch panel in Example 1.
[Example 2]
As the polyfunctional (meth) acrylate contained in the coating solution for forming the undercoat layer, dipentaerythritol hexaacrylate (hexafunctional acrylate, trade name: DPHA, manufactured by Daicel Cytec Co., Ltd.) was used. Further, diethylene glycol diacrylate (bifunctional acrylate, trade name: SR230, manufactured by Sartomer) was used as the polyfunctional (meth) acrylate contained in the coating solution for forming the undercoat layer. Further, silica particles having a particle diameter of 1.4 μm (trade name: Silicia 310, manufactured by Fuji Silysia Chemical Co., Ltd.) were used as particles contained in the coating solution for forming the undercoat layer. A photopolymerization initiator (trade name: IRGACURE 184, manufactured by BASF) was used as a polymerization initiator contained in the coating solution for forming the undercoat layer. As an additive contained in the coating liquid for forming the undercoat layer, a light stabilizer (trade name: TINUVIN152, manufactured by BASF) was used. As a diluting solvent contained in the coating liquid for forming the undercoat layer, a mixed solvent in which methyl ethyl ketone and cyclohexanone were mixed at 1: 1 (weight ratio) was used.

  Then, 30 parts by mass of dipentaerythritol hexaacrylate, 61 parts by mass of diethylene glycol diacrylate, 3 parts by mass of silica particles, 3 parts by mass of a photopolymerization initiator, 3 parts by mass of a light stabilizer, a diluent solvent, The mixture was mixed so that the content was 50% by mass to prepare a coating solution for forming the undercoat layer of Example 2. Next, an undercoat layer was formed using the undercoat layer forming coating solution of Example 2 instead of the undercoat layer forming coating solution of Example 1.

  As the silane coupling compound contained in the coating liquid for forming the conductive layer, 3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3-mercaptopropyltrimethoxysilane ( 8: 2 mixture of trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. Moreover, silver powder (trade name: SPQ03R, manufactured by Mitsui Kinzoku Mining Co., Ltd.) was used as the conductive particles contained in the coating liquid for forming the conductive layer.

Then, instead of 3-glycidoxypropyltriethoxysilane of Example 1, 3-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane were used, and instead of the wet copper powder of Example 1, silver powder was used. A conductive sheet of Example 2 and a resistive touch panel of Example 2 were produced in the same manner as Example 1 except that it was used.
[Example 3]
3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a silane coupling agent contained in the coating liquid for forming the conductive layer. Moreover, silver powder (trade name: SPQ03R, manufactured by Mitsui Kinzoku Mining Co., Ltd.) was used as the conductive particles contained in the coating liquid for forming the conductive layer.

And, instead of 3-glycidoxypropyltriethoxysilane of Example 1, 3-glycidoxypropyltrimethoxysilane was used, except that silver powder was used instead of the wet copper powder of Example 1. In the same manner as in Example 1, the conductive sheet of Example 3 and the resistive touch panel of Example 3 were produced.
[Example 4]
In the coating liquid for forming the conductive layer, the blending ratio of the 1% liquid of the silane coupling compound and the conductive particles was changed from 110: 30 to 140: 50. Thus, the conductive sheet of Example 4 and the resistive film type touch panel of Example 4 were produced.
[Example 5]
The acrylic polymer X contained in the coating solution for forming the undercoat layer was produced by the following method. That is, a monofunctional acrylate, n-butyl methacrylate, methacrylic acid, a molecular weight regulator, a polymerization initiator, and a solvent are charged into a reaction vessel equipped with a nitrogen gas introduction can, a stirrer, and a thermometer, and nitrogen gas is circulated. While stirring, the reaction mixture was stirred and heated to 80 ° C. to obtain an acrylic polymer X having a weight average molecular weight of 7200.

  At this time, 90.0 parts by mass of cyclohexyl methacrylate (trade name: Light Ester CH, manufactured by Kyoeisha Chemical Co., Ltd.) was used as the monofunctional acrylate. The amount of n-butyl methacrylate (trade name: Light Ester NB, manufactured by Kyoeisha Chemical Co., Ltd.) was 1.3 parts by mass. Methacrylic acid (trade name: Light Ester A, manufactured by Kyoeisha Chemical Co., Ltd.) was 4.7 parts by mass. As a molecular weight modifier, n-dodecyl mercaptan (trade name: Thiocalcol 20 manufactured by Kao Corporation) was 3.7 parts by mass. As a polymerization initiator, 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was 0.3 parts by mass. The solvent was 286 parts by mass of propylene glycol monomethyl ether. The SP value of the acrylic polymer X was 10.0, and the glass transition point Tg was 65 ° C.

  As polyfunctional (meth) acrylate contained in the coating liquid for forming the undercoat layer, pentaerythritol triacrylate (trade name: M-305, manufactured by Toagosei Co., Ltd., SP value 12.7, Tg: 250 ° C.) Using. A photopolymerization initiator (trade name: IRGACURE 184, manufactured by BASF) was used as a polymerization initiator contained in the coating solution for forming the undercoat layer. As an additive contained in the coating liquid for forming the undercoat layer, a light stabilizer (trade name: TINUVIN152, manufactured by BASF) was used. As a diluting solvent contained in the coating liquid for forming the undercoat layer, a mixed solvent in which isopropyl alcohol and isobutyl alcohol were mixed at 1: 1 (weight ratio) was used.

The acrylic polymer X is 5 parts by mass, the pentaerythritol triacrylate is 87 parts by mass, the photopolymerization initiator is 4 parts by mass, the light stabilizer is 4 parts by mass, the dilution solvent is 40% by mass. To prepare a coating solution for forming the undercoat layer of Example 5. The conductive sheet of Example 5 was used in the same manner as in Example 4 except that the coating liquid for forming the undercoat layer of Example 5 was used instead of the coating liquid for forming the undercoat layer of Example 4. And the resistive film type touch panel of Example 5 was produced.
[Comparative Example 1]
The formation of the undercoat layer and the corona treatment on the side surface opposite to the back surface hard coat layer of the substrate on which the back surface hard coat layer was formed were omitted. And the coating liquid for conductive layer formation was applied directly on the side surface opposite to the hard coat layer for the back surface to form a conductive layer. A conductive sheet of Comparative Example 1 and a resistive film type touch panel of Comparative Example 1 were produced in the same manner as Example 4 except that the undercoat layer and the corona treatment for the undercoat layer were omitted.
[Comparative Example 2]
As the coating liquid for forming the undercoat layer, a clear hard coating agent (trade name: Forse Seed No. 300C, manufactured by Chugoku Paint Co., Ltd.) was used, and other than this was conducted in the same manner as in Example 4, and the conductivity of Comparative Example 2 was used. Sheet and the resistive film type touch panel of Comparative Example 2 were produced.
[Comparative Example 3]
The conductive sheet of Comparative Example 3 and Comparative Example were the same as Example 4 except that the coating film formed with the coating liquid for forming the primer layer was dried at 100 ° C. to form the primer layer. 3 resistive film type touch panels were produced.
[Comparative Examples 4 to 5]
A coating liquid for forming a conductive layer was prepared in the same manner as in Example 4 except that the blending amounts of the silane coupling compound and the conductive particles were changed as shown in Table 1, and Comparative Example 4 and Comparative Example were compared. The conductive sheet of Example 5 and the resistive film type touch panel of Comparative Example 4 and Comparative Example 5 were produced.

  The surface of the conductive layer and the cross-section of the conductive layer in the conductive sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were observed with a scanning electron microscope, and the film of the conductive layer was obtained. The thickness a of the conductive layer, the thickness of the undercoat layer, the minor axis diameter b of the conductive particles, and the major axis diameter c of the conductive particles were measured. As for the film thickness of the conductive layer, the film thickness of the conductive layer excluding the convex portions of the conductive particles was measured at 10 locations based on the cross-sectional image of the conductive layer, and the average value of the measurement results was defined as the film thickness a of the conductive layer. . Similarly, the average value of 10-point measurement was adopted for the thickness of the undercoat layer. In addition, the surface roughness of the undercoat layer is measured with respect to a measurement area of 278 μm × 210 μm by using an ultra-deep shape measuring microscope (trade name: VK-8500, manufactured by Keyence Corporation) in accordance with JIS B0601-1994. Arithmetic average roughness (Ra), maximum height (Ry), load length ratio (tp, cutting level c = 50%), average interval between irregularities (μm), average distance between local peaks (S) Measured optically. Tables 1 and 2 show these measurement results, the silicon element content in the conductive layer, the content of the conductive particles, the surface roughness of the undercoat layer, and the thickness of the undercoat layer.

In Table 1, silane coupling compounds and conductive particles are represented by the following symbols.
A1: 3-glycidoxypropyltriethoxysilane A2: 8: 2 mixture of 3-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane A3: 3-glycidoxypropyltrimethoxysilane B1: wet copper Powder B2: Silver powder [Evaluation of conductive sheet and touch panel]
In each example and each comparative example, the conductive sheet and resistive film type touch panel obtained in each example were evaluated by the following methods, and the evaluation results are shown in Table 3.
[Transmissivity, haze]
The conductive sheet was cut into 5 cm × 10 cm, and the total light transmittance and haze were measured by a method based on JIS-K7105 using a Nippon Denshoku Industries Co., Ltd. haze meter.
[Anti-Newton ring property (AN property)]
In the resistive touch panel, the 0.8 A polyacetal pen was pressed against the center of the conductive sheet until the upper electrode and the lower electrode were in contact with each other, and the stationary state where the upper electrode and the lower electrode were positioned at a predetermined interval. The pressed state was observed. Then, the state of occurrence of Newton rings during observation was evaluated in four stages according to the following criteria.
[Criteria]
A: Newton ring was not generated at all.

B: Newton ring occurred only when the distance between the electrodes was narrowed.
C: A Newton ring could be seen depending on the viewing angle even in the same state.
D: A Newton ring was seen as it was.
[Glare of image]
Characters and images were displayed on the display surface of a liquid crystal display (screen size: 13.3 inches, 293.5 mm × 165 mm, maximum resolution: 1366 × 768, 0.21 mm pitch). At this time, a resistive touch panel was placed on the display surface of the liquid crystal display, and characters and images visually confirmed through the resistive touch panel were confirmed as an initial state. Next, with the resistive touch panel placed on the liquid crystal display, the resistive touch panel is gradually rotated 180 ° around the central portion of the conductive sheet, and characters visually recognized through the resistive touch panel, and The image change was evaluated according to the following criteria.
[Criteria]
A: The image was always almost uniform, and there was no problem in the visibility of characters and images.

B: When the touch panel was rotated, a slight RGB shift was felt in the white solid part depending on the angle, but there was no problem in the visibility of characters and images.
C: There was glare (uneven brightness of the image), and the image was damaged.

D: Very high glare (brightness unevenness of the image), which was a level that hindered the visibility of characters.
[Writing durability]
The touch panel evaluation machine (Touch Panel Laboratories Co., Ltd., Model: 001-29) was attached with the resistive touch panel and 0.8R polyacetal pen obtained in each example, and at 2.5N load, before the writing test. The linearity of the touch panel was measured. Thereafter, with a 5N load, a reciprocating line having a length of 50 mm was written 500,000 times at an oblique angle of 45 ° in a substantially diagonal direction so that the center of the touch panel was included. After such writing, the linearity of the resistive touch panel was measured, and the degree of deterioration was evaluated in three stages according to the following criteria. The linearity measurement is a method in which pressurization is sequentially input to the entire surface of the resistive touch panel, and the accuracy of the resistive touch panel is evaluated based on the magnitude of the maximum deviation of the detection position with respect to the input position.
[Criteria]
A: The change rate of linearity was less than 3%.

B: The change rate of linearity was 3% or more and less than 5%.
C: The linearity change rate was 5% or more and less than 10%.
D: The linearity change rate was 10% or more.
[Contact resistance measurement]
In the resistive touch panel obtained in each example, a load of 2.5 N was input to the center of the touch panel using a 0.8R polyacetal pen, and after 1 minute had elapsed from the start of load input, the extraction electrode P1 and The resistance between the lead electrode P2 was measured as a contact resistance.

表１が示すように、実施例１から実施例５の導電性シートは、塗工液に含まれる導電性粒子の大きさ、および、形状が、上記式１および式３を満たす水準であり、その塗工液によって形成された導電層は、式２を満たす水準である。

As Table 1 shows, the conductive sheets of Examples 1 to 5 are at a level where the size and shape of the conductive particles contained in the coating liquid satisfy the above Formula 1 and Formula 3, The conductive layer formed by the coating solution is at a level that satisfies Equation 2.

  In addition, the conductive sheets of Example 1 to Example 5 are at a level that satisfies the above (a) as the blending amount of the conductive particles contained in the coating liquid, and the conductive layer formed by the coating liquid is It is a level which satisfies said (b) as a compounding quantity of the electroconductive particle contained in a conductive layer.

  In addition, the conductive sheets of Example 1 to Example 5 are at a level that satisfies the above (c) as the blending amount of the coupling component contained in the coating liquid, and the conductive layer formed by the coating liquid is It is a level that satisfies the above (d) as the blending amount of the coupling component contained in the conductive layer.

  As Table 2 shows, the conductive sheets of Examples 1 to 5 achieve both contact resistance, that is, touch panel sensitivity and scratch resistance at a very high level. Moreover, since the contact resistance between the conductive layer and the other conductive member is suppressed, the content of the polythiophene-based conductive agent having a color derived from the π-conjugated bond is suppressed, and the transmittance of the conductive sheet is also increased. Furthermore, since the polythiophene-based conductive agent is the most expensive among the components constituting the conductive layer, it is possible to reduce the cost of the conductive sheet and hence the cost of the touch panel.

  Moreover, the conductive sheets of Examples 1 to 5 have a high transmittance of 88% or more and a good anti-Newton ring property, and in addition, relative displacement of the conductive sheet with respect to the display image. , Suppresses glare in the image. That is, on the surface of the conductive layer, the arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less, and the load length ratio (tp) is a cutting level. If c = 50%, 25% or more and 45% or less and the average interval (Sm) of the unevenness is 5 μm or more and 20 μm or less, low contact resistance and high scratch resistance In addition to the above, it is possible to realize good anti-Newton ring property and suppression of image glare.

  On the other hand, in Comparative Example 1 where the undercoat layer is omitted, low contact resistance and high scratch resistance are obtained, but anti-Newton ring properties are not sufficient. Even in Comparative Example 2 where the surface of the conductive layer is substantially flat, low contact resistance and high scratch resistance can be obtained, but anti-Newton ring properties are not sufficient. Further, even in Comparative Example 3 in which the arithmetic average roughness (Ra) exceeds 0.18 μm on the surface of the conductive layer, low contact resistance and high scratch resistance can be obtained, but anti-Newton ring property is not sufficient. In Comparative Example 4 in which the content of conductive particles is less than 6%, which is 3.8%, Comparative Example 5 in which sufficient scratch resistance cannot be obtained and the amount of the silane coupling compound is excessive. Shows high contact resistance and low scratch resistance.

  In addition, in the coating liquid for forming a conductive layer, the present invention is not limited to the above examples, and when the mass part of the polythiophene-based conductive agent is 100, the mass part of the conductive particles is in the range of 20 or more and 100 or less. In addition, if the surface roughness shape parameter of the conductive layer satisfies the conditions 1 to 3, the same effects as those of the examples 1 to 5 can be achieved at the level where the above (c) is satisfied. Was recognized.

  In addition, not only in the above-described embodiments, in the formation of the conductive layer, the content of the conductive particles with respect to the mass of the conductive layer is 6% by mass or more and 25% by mass or less, and the conductive layer As long as the surface roughness shape parameter satisfies the conditions 1 to 3, the same effects as those of the examples 1 to 5 were observed at the level satisfying the condition (d). Further, in the conductive layer, when the content of the conductive particles with respect to the mass of the conductive layer is less than 6% by mass, the contact resistance tends to decrease rapidly, and the content of the conductive particles with respect to the mass of the conductive layer. At a level exceeding 25%, the scratch resistance and the tendency of the conductivity to decline rapidly were also observed.

  In addition, in the coating liquid for forming a conductive layer, the present invention is not limited to the above examples, and when the polythiophene-based conductive agent has a mass part of 100, the silane coupling compound has a mass part of 100 or more and 240 or less. In addition, if the surface roughness shape parameter of the conductive layer satisfies the conditions 1 to 3, the level equivalent to the above (a) is the same as that of the above Examples 1 to 5. The effect was recognized.

  Further, the present invention is not limited to the above examples, and the conductive layer has a silicon element content of 3% by mass or more and 7% by mass or less with respect to the mass of the conductive layer, and the surface roughness of the conductive layer. As long as the shape parameter satisfies the conditions 1 to 3, the same effects as those of the examples 1 to 5 were recognized at the level where the condition (b) was satisfied. Further, in the conductive layer, at a level where the content of silicon element relative to the mass of the conductive layer is less than 3% by mass, there is also a tendency for the scratch resistance to decrease rapidly, and the content of silicon element relative to the mass of the conductive layer is At levels exceeding 7% by mass, there was also observed a tendency for the scratch resistance and the conductivity to rapidly decrease.

As mentioned above, according to the said embodiment, the effect listed below is acquired.
(1) On the surface of the conductive layer, the arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less, and the load length ratio (tp) is At the cutting level c = 50%, it is 25% or more and 45% or less, and the average interval (Sm) of the irregularities is 5 μm or more and 20 μm or less. According to the conductive sheet including such a conductive layer and the touch panel including the conductive sheet, high anti-Newton ring property and suppression of image glare can be realized.

  (2) In the coating liquid for forming a conductive layer, when the mass part of the polythiophene-based conductive agent is 100, the mass part of the conductive particles is 20 or more and 100 or less. In the coating liquid for forming the conductive layer, when the mass part of the polythiophene-based conductive agent is 100, the mass part of the silane coupling compound is 100 or more and 240 or less. According to the conductive sheet including the conductive layer formed by such a coating liquid and the touch panel including the conductive sheet, the contact resistance between the conductive layer and another conductive member, that is, the sensitivity of the touch panel is increased. And the abrasion resistance in a conductive layer is improved.

  (3) In the conductive layer, the content, which is the mass of the conductive particles with respect to the mass of the conductive layer, is 6% by mass or more and 25% by mass or less. In the conductive layer, the content of silicon element with respect to the mass of the conductive layer is 3% by mass or more and 7% by mass or less. According to the conductive sheet including such a conductive layer and the touch panel including the conductive sheet, the contact resistance between the conductive layer and another conductive member, that is, the sensitivity of the touch panel is increased, and the resistance in the conductive layer is increased. Abrasion is improved.

  DESCRIPTION OF SYMBOLS 10 ... Electroconductive sheet, 11 ... Base material, 12 ... Conductive layer, 13 ... Back surface layer, 14 ... Undercoat layer, 20 ... Resistive touch panel.

Claims (5)

A substrate;
A conductive layer provided on the substrate;
At the surface of the conductive layer,
The arithmetic average roughness (Ra) defined in JIS B0601-1994 is 0.08 μm or more and 0.18 μm or less,
The load length ratio (tp) is 25% or more and 45% or less at the cutting level c = 50%.
The average interval (Sm) of the irregularities is 5 μm or more and 20 μm or less,
The conductive layer includes a polythiophene-based conductive agent and conductive particles,
The conductive layer satisfies the following formulas 1 and 2 for the film thickness a of the conductive layer and the minor axis diameter b of the conductive particles.
a> 100 nm Formula 1
1.5 <b / a <5 Formula 2 The conductive layer further includes a binder, a silane coupling compound, and a coupling component that is a reaction product of the silane coupling compound,
The content of the conductive particles is 6% by mass or more, and the content of the silicon element is more than 25 wt%, 3 wt% or more and conductivity of claim 1 or less 7 wt% Sheet. The conductive particles are spherical particles dispersed in the conductive layer,
The minor axis diameter b of the conductive particles and the major axis diameter c of the conductive particles satisfy the following formula 3. c / b <2 Formula 3
The conductive sheet according to claim 1 or 2 . The conductive particles are:
The electroconductivity according to any one of claims 1 to 3 , which is at least one selected from the group consisting of silver particles, copper particles, the silver particles whose surface is treated, and the copper particles whose surface is treated. Sheet. A touch panel provided with the electroconductive sheet as described in any one of Claim 1 to 4 .

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