JP2016051271A - Transparent conductive sheet and touch panel sensor prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive sheet having excellent adhesion between a conductive nano ink layer and a transparent conductive layer, and a touch panel sensor prepared therewith.SOLUTION: A transparent conductive sheet comprises a transparent insulation base sheet 1, a transparent conductive layer 2 that is formed of an electrode pattern on at least one side of the transparent insulation base sheet 1 and comprises a conductive component comprising a linear structure, and a conductive nanoparticle ink layer 3 that overlaps a part of the surface of the transparent conductive layer 2 and is formed of a routing wiring pattern connected to the electrode pattern.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transparent conductive sheet. More specifically, at least one surface of the transparent transparent insulating base sheet has a transparent conductive layer and a quick-drying conductive nanoparticle ink layer overlapping with a part of the transparent conductive layer, and the conductive nanoink layer and the transparent conductive layer The present invention relates to a transparent conductive sheet excellent in adhesion and a touch panel sensor using the same.

  A capacitive touch panel sensor is known as a touch panel sensor for realizing a touch panel function. In a capacitive touch panel sensor, an external conductor such as a human finger on the touch panel sensor is utilized by utilizing a change in capacitance that occurs when an external conductor such as a human finger contacts (approaches) the touch panel sensor. The position of is detected. Capacitive touch panel sensors include a surface type and a projection type. The projection type is attracting attention because it is suitable for multi-touch recognition (multi-point recognition).

  A projected capacitive touch panel sensor generally includes a transparent insulating base sheet, a large number of rhombus-shaped x-direction transparent electrode units arranged in the x direction on the upper surface of the transparent insulating base sheet, and a transparent base material. A number of rhombus-shaped transparent electrode units arranged in a line on the bottom surface in the y direction. In this case, adjacent x-direction transparent electrode units are connected in the x-direction by the x-direction connecting portion, and adjacent y-direction transparent electrode units are connected in the y-direction by the y-direction connecting portion.

  A projection capacitive touch panel sensor in which an x-direction transparent electrode unit and a y-direction transparent electrode unit are formed on the same plane has also been proposed. This type of touch panel sensor includes a transparent insulating base sheet, a number of rhombus-shaped x-direction transparent electrode units arranged in the x direction on the top surface of the transparent insulating base sheet, and a transparent x direction on the top surface of the transparent insulating base sheet. A large number of rhombus-shaped transparent electrode units located between the electrode units. Among these, adjacent x-direction transparent electrode units are connected in the x-direction by an x-direction connecting portion provided on the same plane as the x-direction transparent electrode unit and the y-direction transparent electrode unit. Adjacent y-direction transparent electrode units are connected in the y-direction by a y-direction connection portion disposed above the x-direction connection portion via an insulating layer.

  As a method for forming the electrode pattern, there are generally a wet etching method using an acidic aqueous solution, a dry etching method in which a paste containing an acid is printed and heated.

  Further, among the many x-direction transparent electrode units and y-direction transparent electrode units, the x-direction transparent electrode unit and the y-direction transparent electrode unit located at the periphery are routed to transmit the current flowing through the touch panel sensor to an external control unit. Wiring is provided. The region where the lead wiring is provided is a non-display region of the liquid crystal display device when the liquid crystal display device is manufactured by combining the touch panel sensor with a TFT substrate or the like, and therefore the lead wiring does not require transparency.

  As a method for forming the routing wiring, generally, a metal paste in which metal fine particles such as silver (Ag), gold (Au), and copper (Cu) are dispersed in a binder resin is used, and is patterned and dried by a screen printing method or the like. Has been done. Also, a metal layer made of Cu, aluminum (Al) or the like is laminated on the transparent conductive film, and the metal layer is patterned together with the transparent conductive film by a photolithography method to be used as a lead wiring.

  However, in the case where the above metal paste is used and the wiring is formed by screen printing or the like, the metal paste has a high electric resistance value, and good conductivity cannot be obtained. Further, a drying temperature of about 120 to 150 ° C. is necessary, and the transparent insulating base sheet cannot be used because it is stretched and contracted.

  On the other hand, the above metal layer is laminated on a transparent conductive film, and the wiring layer is formed by patterning the metal layer by photolithography, so there are many steps, and there are problems in equipment and cost such as waste liquid treatment in the etching process. There is.

  As a solution to such a problem, recently, it has been proposed to use conductive nanoparticle ink as a printed wiring material. For example, the quick-drying conductive nanoparticle ink disclosed in Patent Document 1 is an ink having a protective ligand having conductivity on the surface of nano-sized inorganic particles and dispersed in water or an alcohol solution. A wiring pattern can be formed on a transparent insulating substrate sheet simply by applying it at room temperature by printing or the like without heating and drying, and it exhibits conductivity similar to that of a bulk metal.

International Publication No. 2011/114713

However, the above-mentioned quick-drying conductive nanoparticle ink layer cannot secure sufficient adhesion on the surface of the transparent conductive layer made of ITO and cannot be peeled off to obtain sufficient electrical reliability. was there.
Therefore, the present invention has a transparent conductive layer and a conductive nanoparticle ink layer overlapping a part of the transparent conductive layer, and a transparent conductive sheet excellent in adhesion between the conductive nanoink layer and the transparent conductive layer, and the same An object of the present invention is to provide a touch panel sensor using the touch panel.

  As a means for solving the above-mentioned problems, the first aspect of the present invention includes a transparent insulating base sheet and a conductive component formed of an electrode pattern on at least one surface of the transparent insulating base sheet and comprising a linear structure. There is provided a transparent conductive sheet comprising: a transparent conductive layer comprising: a conductive nanoparticle ink layer that overlaps a part of the surface of the transparent conductive layer and is formed by a lead wiring pattern connected to the electrode pattern.

  The second aspect of the present invention is the transparent conductive material according to the first aspect, in which the conductive nanoparticle ink layer has a conductive organic π-conjugated ligand as a protective layer on the surface of the inorganic nanoparticles. Provide a sheet.

  According to a third aspect of the present invention, in the second aspect, the inorganic nanoparticles are metal nanoparticles that are any one of gold, silver, copper, platinum, palladium, nickel, ruthenium, indium, and rhodium. The transparent conductive sheet of the aspect is provided.

  Moreover, the 4th aspect of this invention provides the transparent conductive sheet in any one of the 1st-3rd aspect whose said linear structure of the said transparent conductive layer is silver nanofiber or silver nanowire.

  The fifth aspect of the present invention provides a touch panel sensor using one or more transparent conductive sheets according to any one of the first to fourth aspects.

  According to the present invention, the transparent conductive layer in which the quick-drying conductive nanoparticle ink layer is laminated on a part of the surface is a layer containing a conductive component made of a linear structure, and thus is exposed on the surface of the transparent conductive layer. A transparent conductive sheet that exhibits a strong anchor effect by increasing the contact area with the conductive nano ink layer due to the presence of the linear structure, and has excellent adhesion between the conductive nano ink layer and the transparent conductive layer, and the same Touch panel sensor.

It is a top view which shows one Embodiment of the transparent conductive sheet which concerns on this invention. It is sectional drawing which shows the AA cross section of the transparent conductive sheet of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and modifications such as design changes can be made based on the knowledge of those skilled in the art, and such modifications have been added. Embodiments are also included in the scope of the present invention.

  FIG. 1 is a plan view showing an embodiment of a transparent conductive sheet according to the present invention. Moreover, FIG. 2 is sectional drawing which shows the AA cross section of the transparent conductive sheet of FIG. The transparent conductive sheet 6 in FIG. 1 overlaps the transparent insulating base sheet 1, the transparent conductive layer 2 formed in an electrode pattern on one side of the transparent insulating base sheet 1, and a part of the surface of the transparent conductive layer 2. The conductive nanoparticle ink layer 3 is formed of a lead wiring pattern connected to the pattern. In FIG. 1, 4 is a transparent electrode, and 5 is a lead wiring.

[Transparent insulating base sheet]
As the transparent insulating base sheet 1 used in the present invention, those conventionally used for forming a wiring pattern can be applied. For example, a polymer film made of polyethylene, polystyrene, vinyl chloride resin, polyamide, polyimide, polycarbonate, polyethylene terephthalate (PET), vinylidene chloride resin, fluororesin, unsaturated polyester resin, or the like can be used. Further, a glass plate can be used as the transparent insulating substrate sheet 1.

  In the use in the transparent conductive sheet 6 of the present invention, the transparent insulating base sheet 1 is optically less birefringent, or the birefringence is increased to the optical wavelength λ and controlled to λ / 4 or λ / 2. Those having no birefringence controlled at all can be appropriately selected depending on the application. As described here, when appropriate selection is made according to the application, for example, polarized light such as polarizing plate, retardation film, inner type touch panel sensor used in liquid crystal displays, linearly polarized light, elliptically polarized light, circularly polarized light, etc. The case where the transparent conductive sheet 6 of this invention is used as a display member which expresses a function can be mention | raise | lifted.

  The thickness of the transparent insulating substrate sheet 1 can be appropriately determined, but is generally about 10 to 500 μm, particularly preferably 20 to 300 μm, and more preferably 30 to 200 μm from the viewpoint of workability such as strength and handleability. More preferred. Moreover, when importance is attached to transparency, the total light transmittance is preferably 80% or more.

[Transparent conductive layer]
The transparent conductive layer of the present invention contains a conductive component composed of a linear structure.

  The linear structure in the present invention is a structure in which the ratio of the length of the short axis to the length of the long axis, that is, the aspect ratio = the length of the long axis / the length of the short axis is larger than 5. For example, the spherical aspect ratio is 1). Preferably, the aspect ratio is 10 or more. Examples of the linear structure include a fibrous conductor and a needle-like conductor such as a whisker. Although the lengths of the short axis and the long axis differ depending on the type of the fibrous structure and cannot be uniquely limited, the length of the short axis is smaller than the pattern to be formed and is 1 nm to 100 nm (1 μm). Preferably, the length of the major axis may be such that the aspect ratio = the length of the major axis / the length of the minor axis is greater than 10 with respect to the length of the minor axis. .1 mm) is preferred.

Examples of the fibrous conductor include a carbon-based fibrous conductor, a metal-based fibrous conductor, and a metal oxide-based fibrous conductor. Examples of carbon-based fibrous conductors include polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, rayon-based carbon fiber, glassy carbon, CNT, carbon nanocoil, carbon nanowire, carbon nanofiber, carbon whisker, graphite fibril, etc. Is mentioned. Metallic fibrous conductors include gold, platinum, silver, nickel, silicon, stainless steel, copper, brass, aluminum, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, manganese, technetium, rhenium, iron, Examples thereof include fibers and nanowire-like metals and alloys manufactured from osmium, cobalt, zinc, scandium, boron, gallium, indium, silicon, germanium, tin, magnesium, and the like. Examples of the metal oxide fibrous conductor include InO ₂ , InO ₂ Sn, SnO ₂ , ZnO, SnO ₂ —Sb ₂ O ₄ , SnO ₂ —V ₂ 0 ₅ , TiO ₂ (Sn / Sb) O ₂ , SiO. ₂ (Sn / Sb) O ₂ , K ₂ O—nTiO ₂ — (Sn / Sb) O ₂ , fibrous or nanowire-like metal oxides and metal oxides produced from K ₂ O—nTiO ₂ —C, etc. Compound complex and the like. These may be subjected to a surface treatment. Furthermore, what coated or vapor-deposited the said metal, the said metal oxide, or CNT on the surface of nonmetallic materials, such as a vegetable fiber, a synthetic fiber, and an inorganic fiber, is also contained in a fibrous conductor.

An acicular conductor such as a whisker is a compound made of a metal, a carbon-based compound, a metal oxide, or the like. The metal belongs to the group IIA, IIIA, IVA, VA, VIA, VIIA, VIII, IB, IIB, IIIB, IVB or VB in the short periodic table of elements. Elements. Specifically, gold, platinum, silver, nickel, stainless steel, copper, brass, aluminum, gallium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, manganese, antimony, palladium, bismuth, technetium, rhenium, Examples thereof include iron, osmium, cobalt, zinc, scandium, boron, gallium, indium, silicon, germanium, tellurium, tin, magnesium, and alloys containing these. Examples of the carbon-based compound include carbon nanohorn, fullerene, and graphene. Examples of the metal oxide include InO ₂ , InO ₂ Sn, SnO ₂ , ZnO, SnO ₂ —Sb ₂ O ₄ , SnO ₂ —V ₂ O ₅ , TiO ₂ (Sn / Sb) O ₂ , SiO ₂ (Sn / Sb). ) O ₂ , K ₂ O—nTiO ₂ — (Sn / Sb) O ₂ , K ₂ O—nTiO ₂ —C, and the like.

  Among these linear structures, silver nanofibers, silver nanowires, and CNTs can be preferably used from the viewpoints of optical properties such as transparency and conductivity.

  The transparent conductive film of the present invention can be formed by applying a linear structure dispersion. In order to obtain a linear structure dispersion, the linear structure is generally subjected to a dispersion treatment together with a solvent by a mixing and dispersing machine or an ultrasonic irradiation device, and it is desirable to add a dispersant.

  The dispersing agent is not particularly limited as long as the linear structure can be dispersed, but the transparent conductive layer 2 containing the linear structure obtained by applying the linear structure dispersion liquid onto the transparent insulating substrate sheet 1 and drying the transparent conductive layer 2 is transparent. From the viewpoints of adhesion to the insulating base sheet 1, film hardness, and scratch resistance, it is preferable to select a synthetic polymer or a natural polymer. Furthermore, a crosslinking agent may be added within a range that does not impair the dispersibility.

  Synthetic polymers include, for example, polyether diol, polyester diol, polycarbonate diol, polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, acetal group-modified polyvinyl alcohol, butyral group-modified polyvinyl alcohol, silanol group-modified polyvinyl alcohol, Ethylene-vinyl alcohol copolymer, ethylene-vinyl alcohol-vinyl acetate copolymer resin, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylic resin, epoxy resin, modified epoxy resin, phenoxy resin, modified phenoxy resin, phenoxy Ether resin, phenoxy ester resin, fluorine resin, melamine resin, alkyd resin, phenol resin, polyacryl Bromide, polyacrylic acid, polystyrene sulfonic acid, polyethylene glycol, polyvinylpyrrolidone.

  Natural polymers include, for example, polysaccharides such as starch, pullulan, dextran, dextrin, guar gum, xanthan gum, amylose, amylopectin, alginic acid, gum arabic, carrageenan, chondroitin sulfate, hyaluronic acid, curdlan, chitin, chitosan, cellulose and the like It can be selected from derivatives. The derivative means a conventionally known compound such as ester or ether. These may be used alone or in combination of two or more. Among these, polysaccharides and derivatives thereof are preferable because of excellent dispersibility of CNTs. Furthermore, cellulose and derivatives thereof are preferable because of high film forming ability. Of these, esters and ether derivatives are preferable, and specifically, carboxymethyl cellulose and salts thereof are preferable.

  It is also possible to adjust the blending ratio of CNT and dispersant. The compounding ratio of the CNT and the dispersing agent is preferably a compounding ratio that does not cause any problems in adhesion, hardness, and scratch resistance with the transparent insulating substrate sheet 1. Specifically, the CNT is preferably in the range of 10% by mass to 90% by mass with respect to the entire conductive layer. More preferably, it is the range of 30 mass%-70 mass%. When the CNT content is 10% by mass or more, the conductivity necessary for the touch panel sensor is easily obtained, and furthermore, it is easy to apply uniformly without applying to the surface of the transparent insulating substrate sheet 1, and thus a good appearance. -High quality conductive laminates can be supplied with high productivity. When the content is 90% by mass or less, the dispersibility of CNTs in a solvent is improved and is less likely to aggregate, which makes it easy to obtain a good CNT coating layer and good productivity. Furthermore, the coating film is also strong, and scratches are less likely to occur during the production process, so that the uniformity of the sheet resistance value can be maintained.

  In addition, metal and metal oxide nanowires are disclosed in JP-T 2009-505358, JP-A 2009-146747, and JP-A 2009-70660. In addition, as a needle-like conductor such as a whisker, for example, WK200B, WK300R, WK500 of DENTOR WK series (manufactured by Otsuka Chemical Co., Ltd.), which is a composite compound of potassium titanate fiber and tin and antimony oxide, DENTOR TM series (manufactured by Otsuka Chemical Co., Ltd.) TM100, which is a composite compound of silicon dioxide fiber, tin and antimony oxide, is commercially available.

  In the present invention, the linear structures as described above can be used alone or in combination, and other micro-to-nano conductive materials may be added as needed. It is not limited to these.

  Moreover, the transparent conductive layer 2 of this invention can form a protective layer by making a linear structure cover a protective material as needed, and hardening this protective material. As the protective material, an acrylic ultraviolet curable resin is preferably used. The thickness of the protective layer is suitably in the range of 10 to 500 nm, preferably in the range of 50 to 400 nm, and more preferably in the range of 100 to 300 nm.

  The transparent conductive layer 2 of the present invention is preferably formed by applying a conductive layer forming coating solution by a wet coating method. Examples of the wet coating method include a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a slit die coating method, a spin coating method, an extrusion coating method, a slide bead coating method, and a curtain coating method. The slit die coating method, the extrusion coating method, the slide bead coating method, and the curtain coating method, which can be applied to the transparent insulating substrate sheet 1 in a non-contact manner, are preferred, and the slit die coating method is particularly preferred.

  The transparent conductive layer 2 of the present invention forms the transparent electrode 4 with various electrode patterns according to the application to which the transparent transparent conductive sheet 6 is applied. This pattern can be formed by any known method for selectively removing the material forming the transparent conductive layer 2. For example, after applying a resist on the transparent conductive layer 2 and forming a pattern by exposure and development, a photolithography method in which a part of the transparent conductive layer 2 is chemically dissolved, a method of vaporizing by a chemical reaction in vacuum, a laser Examples include a method of sublimating the transparent conductive layer 2. When a laser is used, it is not always necessary to remove all unnecessary conductive parts. For example, the linear structure in the transparent conductive layer 2 may be disconnected for insulation.

[Conductive nanoparticle ink layer]
The conductive nanoparticle ink layer 3 of the present invention has an organic π-conjugated ligand having conductivity on the surface of the inorganic nanoparticles as a protective layer, and the organic π-conjugated ligand is π-bonded to the inorganic nanoparticles. It has conductivity. Here, π-junction refers to parallel bonding of the π-conjugated plane of a π-conjugated molecule to the surface of inorganic nanoparticles. The organic π-conjugated ligand is an organic ligand that acts on inorganic nanoparticles with such a π junction.

  Inorganic nanoparticles are made of gold (Au), silver (Ag), copper, platinum, palladium, nickel, ruthenium, indium, rhodium, any two or more mixtures, or any two or more Alloys can be used.

  The particle diameter of the inorganic nanoparticles is preferably as small as about 15 nm. When fine nanoparticles are used, the nano ink can be regarded as a complete solution, and a pretreatment process such as stirring is not required. On the other hand, as the particle size increases, it becomes closer to the state where fine particles are floating in the liquid rather than a uniform solution, and precipitation occurs over time, so it is necessary to stir with a mixer before use. .

  Further, the inorganic nanoparticles may be either semiconductor particles or conductive oxide particles.

  Organic π-conjugated ligands have a relatively small ligand layer and a relatively small resistance because the π orbitals are positioned in a direction that favors electrical conduction between particles. Conductivity develops in the organic π-conjugated ligand due to the interaction between the particles and the orbit. Therefore, the conductive nanoparticle ink layer 3 has conductivity similar to that of a bulk metal.

  The π-junction is a strong interaction between an organic π orbital and an inorganic nanoparticle orbit caused by the organic matter π orbit approaching the surface of the inorganic nanoparticle. The strength of the π junction can be quantitatively evaluated by ultraviolet-visible spectrum measurement. Porphyrin and phthalocyanine have a characteristic absorption called a soret band and a Q band in the visible region. When a strong π junction is developed, the organic π orbitals are metallized by strong organic-inorganic orbital interaction, and the above characteristic absorption is significantly broadened. In order to obtain conductive nanoparticles, a strong π junction and proximity between the particles is essential.

  Examples of organic π-conjugated ligands include amino groups, mercapto groups, hydroxyl groups, carboxyl groups, phosphine groups, phosphonic acid groups, halogen groups, selenol groups, sulfide groups, which are substituents coordinated on the surface of inorganic nanoparticles. A selenoether group having one or a plurality of substituents can be used.

  The organic π-conjugated ligand includes a hydroxyl group, a carboxyl group, an amino group, an alkylamino group, an amide group, an imide group, which are substituents that make the inorganic nanoparticles soluble in a water-containing solvent and an alcohol solvent. A phosphonic acid group, a sulfonic acid group, a cyano group, a nitro group, or a derivative thereof with one or more substituents may be used. For example, as an organic π-conjugated ligand, OTAP, that is, 2,3,9,10,16,17,23,24-octakis [(2-N, N-dimethylaminoethyl) thio] phthalocyanine, OTAN, That is, 2,3,11,12,20,21,29,30-octakis [(2-N, N-dimethylaminoethyl) thio] naphthalocyanine can be used.

  In addition, if the organic π-conjugated ligand whose work function obtained by density functional calculation (DFT calculation) of the compound molecule is 5.5 eV or less, not only metal-based conductive particles such as gold and silver but also Since carbon black and carbon nanotubes have similar work functions, it is considered that a stronger hybrid orbit is generated by a so-called π junction, and conductivity is generated. That is, if the organic π-conjugated ligand having a work function of 5.5 eV or less is used, it is possible to use conductive particles made of carbon black or carbon nanotubes instead of the inorganic nanoparticles described above.

  For example, an ink jet printing method is recommended as a method of forming the conductive nano ink layer 3 with the pattern of the wiring 5 by drawing around the conductive nano ink layer 3. Since the conductive nano ink used has a viscosity of several millipascals and is equivalent to water, it cannot be used for screen printing. In addition, a printing plate and heat processing become unnecessary by using the inkjet printing method. If heat treatment is not necessary, printing can be performed on the transparent insulating base sheet 1 having no heat resistance, so that the degree of freedom in design is improved and a drying facility is not required. In addition, it is also possible to form a hydrophilic / hydrophobic region on the surface of the transparent insulating substrate sheet 1 on which the transparent conductive layer 2 is formed, and apply the conductive nano ink only to the hydrophilic region using a difference in wettability.

  The transparent conductive layer 2 of the present invention is not a conventional ITO layer but includes a conductive component composed of the above-described linear structure, and is conductive due to the presence of the linear structure exposed on the surface of the transparent conductive layer 2. It is considered that the adhesiveness with the conductive nano ink layer 3 is improved without exerting a primer treatment or the like by exhibiting a strong anchor effect by increasing the contact area with the conductive nano ink layer 3.

  From the viewpoint of the adhesion strength, the longer the length of the linear structure, the larger the anchor effect can be obtained, and therefore the adhesion between the transparent conductive layer 2 and the conductive nano ink layer 3 becomes better.

  In addition, although the pattern of the transparent electrode 4 shown in FIG. 1 is carrying out strip shape, the electrode pattern of the transparent conductive sheet 6 of this invention is not limited to this. It can be formed with various electrode patterns described in the background art section of this specification.

[Touch panel sensor]
The touch panel sensor of the present invention is one in which the transparent conductive sheet 6 of the present invention is used in a single layer or a plurality of sheets, and is further combined with other members as necessary. For example, a resistive touch panel sensor And a capacitive touch panel sensor. When the transparent conductive sheet 6 is used as a capacitive touch panel sensor using a single layer, the transparent conductive layer 2 and the conductive nano ink layer 3 can be provided on both surfaces of the transparent insulating base sheet 1. These touch panel sensors on which the transparent conductive film of the present invention is mounted are used, for example, by attaching a lead wire and a drive unit and incorporating it on the front surface of a liquid crystal display.

  Next, examples and comparative examples will be described.

<Example 1>
A polyethylene terephthalate (PET) film is used as a transparent insulating substrate sheet, a transparent conductive layer containing silver nanofibers is formed on one surface of the PET film by a reverse coater method, and silver nanoparticles are formed on the surface of the transparent conductive layer by an inkjet method. An ink layer was formed to prepare a transparent conductive sheet.

<Example 2>
A transparent conductive sheet was prepared in the same manner as in Example 1 except that gold nanoparticles were used instead of silver nanoparticles.

<Comparative Example 1>
A polyethylene terephthalate (PET) film is used as a transparent insulating substrate sheet, a transparent conductive layer made of ITO is formed on one surface of the PET film by a sputtering method, and a silver nanoparticle ink layer is formed on the surface of the transparent conductive layer by an inkjet method Thus, a transparent conductive sheet was prepared.

<Comparative Example 2>
A transparent conductive sheet was prepared in the same manner as in Comparative Example 1 except that gold nanoparticles were used in place of the silver nanoparticles.

  A weather resistance test was performed on each of the transparent conductive sheets prepared in Examples and Comparative Examples under the above conditions.

[Evaluation of adhesion of conductive nanoparticle ink layer]
On the surface of the laminated body of the transparent conductive layer and the conductive nanoparticle ink layer of the transparent conductive sheet, according to the grid pattern method described in JIS K5400, 10 pieces are used with a cutter knife at intervals of 1 mm in both vertical and horizontal directions. Each cell was scratched, and a cellophane tape was applied and peeled off. At this time, it was observed whether the conductive nanoparticle ink layer was peeled off from the surface of the transparent conductive layer.

  As a result of the evaluation of the above-mentioned crosscut tape peel, peeling occurred in the entire area in the comparative example, whereas peeling did not occur in the example. The transparent conductive sheet of an Example has confirmed that the durability with respect to a weather resistance test was improving compared with the transparent conductive sheet of a comparative example.

DESCRIPTION OF SYMBOLS 1 Transparent insulating base sheet 2 Transparent conductive layer 3 Conductive nanoparticle ink layer 4 Transparent electrode 5 Lead-out wiring 6 Transparent conductive sheet

Claims (5)

A transparent insulating base sheet;
A transparent conductive layer formed of an electrode pattern on at least one surface of the transparent insulating base sheet and comprising a conductive component composed of a linear structure;
A transparent conductive sheet comprising: a conductive nanoparticle ink layer formed by a lead wiring pattern that overlaps a part of the surface of the transparent conductive layer and is connected to the electrode pattern.   The transparent conductive sheet according to claim 1, wherein the conductive nanoparticle ink layer has a conductive organic π-conjugated ligand as a protective layer on the surface of the inorganic nanoparticles.   The transparent conductive sheet according to claim 2, wherein the inorganic nanoparticles are metal nanoparticles of any one of gold, silver, copper, platinum, palladium, nickel, ruthenium, indium, and rhodium.   The transparent conductive sheet according to claim 1, wherein the linear structure of the transparent conductive layer is a silver nanofiber or a silver nanowire. A touch panel sensor using at least one transparent conductive sheet according to claim 1.

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