JP2011210148A - Method for manufacturing conductive member for touch panel and touch panel using the conductive member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for lowering a resistance value of wiring structure to be formed in a frame part to narrow a frame in a touch panel and for manufacturing the touch panel with a high efficiency.SOLUTION: In the method for manufacturing a conductive member for the touch panel having the wiring structure, at least a part of the wiring structure consists of: a silver film formed by processing coating obtained by applying and drying a silver ultrafine particle containing component at least containing silver ultrafine particles with average particle diameter of ≤0.1 μm and polymer latex, or a silver film formed by processing coating obtained by applying and drying a silver ultrafine particle containing component at least containing silver ultrafine particles with the average particle diameter of ≤0.1 μm, polymer latex and water-soluble halogenide by irradiation with ultraviolet rays and/or re-giving of moisture.

Description

  The present invention relates to a method for producing a conductive member for a touch panel having a wiring structure, wherein at least a part of the wiring structure contains silver ultrafine particles having an average particle size of 0.1 μm or less and a polymer latex. A silver film formed by treating a film obtained by applying and drying a fine particle-containing composition, or a silver ultrafine particle containing at least an ultrafine silver particle having an average particle size of 0.1 μm or less, a polymer latex, and a water-soluble halide. It is related with the manufacturing method of the electroconductive member for touchscreens which consists of a silver film formed by processing the film obtained by apply | coating and drying the containing composition by ultraviolet irradiation and / or re-application of moisture.

  Touch panel panels are rapidly spreading as input devices such as small ATMs such as bank ATMs, vending machines, copiers, facsimiles, portable game machines, information boards, car navigation, mobile phones, and PDAs.

  The touch panel system is divided into a resistive film system, an optical system, a capacitive system, an ultrasonic system, a pressure system, an electromagnetic wave induction system, a vibration detection system, etc., and a resistive film system or a capacitive system touch panel is widely used. It has been. In these touch panels, a patterned transparent conductive film or a conductive member for a touch panel having a wiring structure is used as a part of the structure, and the wiring structure is provided on the frame portion by printing, for example, silver paste. .

  In FIG. 1, the schematic sectional drawing of the electroconductive member for touchscreens is shown. A transparent conductive film 2 is formed on a substrate 1 such as a film or glass, and a wiring 3 is formed in the frame portion. In some cases, the transparent conductive film 2 is not provided under the wiring 3. A set of wirings including only the wiring 3 or the wiring 3 and the transparent conductive film 2 is called a wiring structure. Generally, the wiring 3 is formed by screen printing a resin-type silver paste.

  In recent years, a touch panel has been applied to a small information terminal device, and in order to secure a wide input area, it is required to narrow the width of the frame portion (narrow frame). When the frame portion is narrowed, the width of the wiring becomes narrow accordingly, and the resistance value and variation of the wiring increase, and there is a problem that the detection position accuracy and sensitivity decrease. There has been a demand for wiring, that is, wiring having a low volume resistance. The volume resistivity of the conductor obtained by printing and heat-curing the previous resin-type silver paste is several tens of times that of bulk silver, which is insufficient to enable thinning. Furthermore, the heat curing time is required to be about 10 to 30 minutes at 120 to 150 ° C., and the production efficiency is low.

  Therefore, for example, in Japanese Patent Application Laid-Open No. 2002-358163 (Patent Document 1), the wiring structure is a fired film of gold paste obtained by mixing gold powder or gold powder and a small amount of metal powder in a resin solution, or an organic gold compound in a resin solution. A manufacturing method is disclosed in which a low resistance wiring is formed by forming a fired film of a gold paste mixed with.

  However, since this method requires baking at 500 ° C., it cannot be used with a film substrate such as a PET film, and further, there is a problem that the production efficiency is low because time is required for baking.

  In recent years, capacitive touch panels have been widely used, but the number of wires is much larger than that of resistive film methods, and thinner and lower resistance wires are required for narrower frames. is needed.

  Therefore, for example, in the example of JP 2010-39816 A (Patent Document 2), a silver alloy film is formed by a vacuum process, and this is etched to form a low resistance wiring structure. Is disclosed. A silver alloy formed by a vacuum process exhibits a low volume resistivity of several times or less of the bulk state of the alloy, but has a problem of low material use efficiency and manufacturing efficiency because the vacuum process is used.

JP 2002-358163 A JP 2010-39816 A

  An object of the present invention is to provide a method for manufacturing a touch panel with a high efficiency by reducing the resistance value of a wiring structure formed in a frame portion, enabling a narrow frame.

The above object of the present invention has been basically achieved by the following invention.
1. A method for manufacturing a conductive member for a touch panel, wherein a part of a wiring structure formed in a frame portion of the touch panel contains silver ultrafine particles having an average particle size of 0.1 μm or less and a polymer latex in an aqueous medium. A silver film formed by treating the coating (Z) obtained by applying and drying the silver ultrafine particle-containing composition by the method described in (A) to (D) below, or at least an average particle in an aqueous medium A coating obtained by applying and drying a composition containing ultrafine silver particles having a diameter of 0.1 μm or less, a polymer latex and a water-soluble halide, and drying is treated by irradiation with ultraviolet rays and / or re-application of moisture. A method for producing a conductive member for a touch panel, characterized by comprising a silver film formed.
(A) Contact between an aqueous solution containing a halogen inorganic salt and the coating (Z).
(B) Contact between an aqueous solution containing a reducing compound capable of reducing silver ions and the coating (Z).
(C) Contact between an aqueous solution containing an acid salt having a sulfur atom in the molecule and the coating (Z).
(D) Contact between an aqueous solution containing a dicarboxylic acid compound having 3 or more carbon atoms and the coating (Z).
2. 2. The method for manufacturing a conductive member for a touch panel as described in 1 above, wherein the wiring structure formed on the frame portion of the touch panel is patterned by etching.

  According to the present invention, it is possible to form a wiring structure with a low resistance value in the frame portion of the touch panel, and it is possible to narrow the frame of the resistive film type or capacitive type touch panel.

It is a schematic sectional block diagram of the wiring structure formed in a frame part as an example of the electroconductive member for touchscreens of this invention. It is a schematic diagram for illustrating a frame part as an example of the conductive member for touch panels of the present invention. It is a schematic diagram which shows the printing part of a frame part as an example of the electroconductive member for touchscreens of this invention. It is a schematic diagram of the pattern formed as an example of the electroconductive member for touchscreens of this invention. It is a schematic diagram of the pattern to form as an example of the electroconductive member for touchscreens of a comparative example. It is a schematic diagram of the pattern to form as an example of the electroconductive member for touchscreens of a comparative example.

  Hereinafter, the present invention will be described in detail. In addition, the numbers attached to the base material, the wiring, etc. represent the symbols in the figure.

  In the present invention, the conductive member for a touch panel is a conductive member used for a resistive film type or capacitive type touch panel, and has a transparent conductive film 2 patterned on a substrate 1 and a wiring structure. ing. In the case of the resistance film method, as is known as a 4-wire type or an 8-wire type, a wiring structure in which several low resistance wirings 3 are routed around the frame portion is formed, and wiring is provided at the end of the conductive member Are connected to an external connection FPC (flexible printed circuit board) by ACP (anisotropic conductive paste) or ACF (anisotropic conductive film). In the capacitance method, a wiring structure is formed in which a large number of wirings 3 individually drawn out from a large number of patterned transparent conductive films are routed to the frame portion, and are similarly collected at the end and connected to the FPC.

  In this invention, a part of wiring structure formed in the frame part of the said touch panel is formed from a silver film, and the silver ultrafine particle containing composition is used for formation of this silver film. Since the volume resistivity of the silver film showing its conductivity is as low as about 3 to 10 times that of metallic silver, it has a resistance value as compared with a wiring having the same cross-sectional area formed from a conventional resin-type silver paste. If the resistance value is the same, the wiring can be made thinner, and the wiring structure can be densified and the frame can be narrowed. In addition, if the resistance value is the same, it is possible to make the wiring thinner, so that it can be suitably used when manufacturing a thinner touch panel.

  The silver ultrafine particle-containing composition in the present invention is added to the aqueous medium in addition to silver ultrafine particles, polymer latex, or silver ultrafine particles, polymer latex, water-soluble halide, depending on the printing or coating method. Thickeners for viscosity adjustment (xanthan gum, polyacrylic acid, carboxymethylcellulose, carboxyvinyl polymer, biocellulose, etc.), high boiling point solvents for controlling drying (ethylene glycol, glycerin, etc.), surfactants for surface tension adjustment ( In addition to sodium alkyl sulfates, polyoxyethylene alkyl ethers, sodium polyoxyethylene nonylphenyl ether sulfate, fluorine-based surfactants, etc.), a composition containing an antifoaming agent, a leveling agent and the like is shown.

  In the present invention, the aqueous medium refers to a solvent portion other than the solid content in the composition containing silver ultrafine particles, indicating that water is at least 80% by mass or more, preferably 90% by mass or more, and particularly preferably 98%. It means that it is at least mass%. Examples of the solvent other than water include organic solvents having high miscibility with water, such as alcohols and glycols.

  The silver ultrafine particles used in the present invention are metal ultrafine particles in which the proportion of silver is at least 50% by mass or more, preferably the proportion of silver is 70% by mass or more, and particularly preferably 90% by mass or more. It is. Examples of metals contained other than silver include gold, copper, platinum, palladium, rhodium, ruthenium, iridium, osmium, nickel, and bismuth. Metals other than silver may be contained in the silver ultrafine particles, or silver ultrafine particles and metal ultrafine particles other than silver may be mixed.

  The average particle diameter of the silver ultrafine particles needs to be 0.1 μm or less, preferably 0.05 μm or less, from the viewpoint of dispersion stability of the silver ultrafine particles contained in the silver ultrafine particle-containing composition. The average particle diameter of the ultrafine silver particles can be determined by observation under an electron microscope. Specifically, a silver ultrafine particle dispersion is coated on a polyethylene terephthalate film, dried, and observed with a scanning electron microscope. The diameter of a circle equal to the projected area of each of 100 particles existing within a certain area is obtained. The average is obtained as the particle diameter.

  Silver ultrafine particles include vapor evaporation in which the metal is evaporated in an inert gas and cooled / condensed and recovered by collision with the gas, laser ablation that is evaporated / condensed and recovered in the liquid by the energy of laser irradiation, and aqueous solution Chemical reduction method that reduces and generates / recovers metal ions in solution, method by pyrolysis of organometallic compound part, method by reduction of metal chloride in gas phase, method for reduction of oxide in hydrogen, etc. The thing manufactured by the well-known various method can be used preferably. In the present invention, a product prepared by a chemical reduction method is more preferable from the viewpoint of facilitating preparation of a composition containing ultrafine silver particles, and a water-soluble polymer compound acting as a dispersant and a polysaccharide as a reducing agent are used. The prepared product is particularly preferable.

  The polymer latex used in the present invention will be described. Since an aqueous medium is used in the present invention, it is preferable to use an emulsion which is an aqueous dispersion of various known latexes such as a homopolymer and a copolymer, as the polymer latex. Homopolymers include polymers such as vinyl acetate, vinyl chloride, styrene, methyl acrylate, butyl acrylate, methacrylonitrile, butadiene, and isoprene. Copolymers include ethylene / butadiene copolymers and styrene / butadiene copolymers. Polymer, styrene / p-methoxystyrene copolymer, styrene / vinyl acetate copolymer, vinyl acetate / vinyl chloride copolymer, vinyl acetate / diethyl maleate copolymer, methyl methacrylate / acrylonitrile copolymer, methyl methacrylate・ Butadiene copolymer, methyl methacrylate / styrene copolymer, methyl methacrylate / vinyl acetate copolymer, methyl methacrylate / vinylidene chloride copolymer, methyl acrylate / acrylonitrile copolymer, methyl acrylate / butadiene Polymer, methyl acrylate / styrene copolymer, methyl acrylate / vinyl acetate copolymer, acrylic acid / butyl acrylate copolymer, methyl acrylate / vinyl chloride copolymer, butyl acrylate / styrene copolymer, ethylene vinyl chloride copolymer There are polymers, polyesters, various polyurethanes and the like. Among these, polyester latex, acrylic latex and polyurethane latex are preferably used, and polyurethane latex is more preferable from the viewpoint of conductivity. The average particle size of the polymer latex is preferably 0.01 to 10 μm, more preferably 0.02 to 5 μm. From the viewpoint of conductivity obtained, the average particle diameter of the polymer latex is preferably larger than that of the ultrafine silver particles.

  The glass transition temperature or the minimum film-forming temperature of the polymer latex is preferably equal to or lower than the ambient temperature exposed after the silver ultrafine particle-containing composition is applied, from the viewpoint of manifesting the binder function. Although there is no particular lower limit of the glass transition temperature or the minimum film-forming temperature, it is generally −40 ° C. or higher in commercially available polymer latex.

  Examples of the water-soluble halide used in the present invention include hydrogen halide and inorganic salts. Examples of the hydrogen halide include hydrochloric acid and hydrobromic acid. Examples of inorganic salts include lithium salts, sodium salts, potassium salts, ammonium salts, zirconium salts, aluminum salts, magnesium salts, calcium salts, ammonium salts, and the like. For example, lithium chloride, sodium chloride, potassium chloride, calcium chloride, ammonium chloride, lithium bromide, sodium bromide, potassium bromide, calcium bromide, ammonium bromide, lithium iodide, sodium iodide, potassium iodide, etc. I can list.

  The exemplified water-soluble halogen compounds can be used alone or in combination of two or more. From the viewpoint of conductivity obtained, sodium chloride, potassium chloride, and ammonium chloride are particularly preferable.

  In the present invention, a part of the wiring structure formed in the frame portion of the touch panel is formed from a silver film. As a method for forming this silver film, the following two methods can be shown.

The first method is to apply a coating (Z) obtained by coating and drying a silver ultrafine particle-containing composition containing at least an ultrafine silver particle having an average particle size of 0.1 μm or less and a polymer latex in an aqueous medium, It is a method of forming a silver film by processing by the method described in (A) to (D).
(A) Contact between an aqueous solution containing a halogen inorganic salt and the coating (Z).
(B) Contact between an aqueous solution containing a reducing compound capable of reducing silver ions and the coating (Z).
(C) Contact between an aqueous solution containing an acid salt having a sulfur atom in the molecule and the coating (Z).
(D) Contact between an aqueous solution containing a dicarboxylic acid compound having 3 or more carbon atoms and the coating (Z).

  In the case of this method, the content of the polymer latex is preferably such that the mass ratio of silver: polymer latex in the silver ultrafine particle-containing composition is 1: 0.01 to 1: 0.4, and more preferably 1: 0. More preferably, it is 0.03 to 1: 0.3. When the ratio is more than 1: 0.4, ultrafine silver particles are trapped in the polymer latex film, and the conductivity may deteriorate. Moreover, if it is less than 1: 0.01, the effect of the desired adhesiveness by polymer latex may not be acquired.

  As the aqueous solution containing the halogen inorganic salts used in the present invention described in (A) above, inorganic salts such as alkali metal salts such as chlorine, bromine and iodine, alkaline earth metal salts and ammonium salts can be widely used. Higher solubility in water is preferable. Specifically, sodium chloride, potassium chloride, lithium chloride, calcium chloride, ammonium chloride, sodium bromide, potassium bromide, calcium bromide, ammonium bromide, sodium iodide, and iodide. An aqueous solution containing a halogen salt such as potassium, and an inorganic polymer halide having halogen as a counter ion, for example, polyaluminum hydroxide stably containing a basic and polynuclear condensed ion (Taki Chemical Co., Ltd.) As an example of the polyaluminum chloride, an aqueous solution containing Purachem WT from Riken Green Co., Ltd.) can be used.

  As a reducing compound capable of reducing silver ions used in the present invention described in (B) above, a reducing agent used in producing silver nanoparticles or a reducing agent used in electroless plating is used. I can do it. These reducing compounds are described by Katsuaki Suganuma, metal nanoparticle paste inkjet fine wiring, CMC Publishing (2006), Electroplating Research Group, Electroless Plating Basics and Applications, Nikkan Kogyo Shimbun (1994), etc. Has been.

  Specifically, ascorbic acid, erythorbic acid, citric acid, and their alkali metal salts, alkaline earth metal salts, ammonium salts, etc., and hydrazine, hydrazinium salts (such as hydrazinium sulfate and hydrazinium carbonate), aldehydes (formaldehyde, Aliphatic saturated aldehydes such as acetaldehyde and propionaldehyde, aliphatic dialdehydes such as glyoxal, succindialdehyde and glutaraldehyde, unsaturated aldehydes such as acrolein, crotonaldehyde, and propiolaldehyde), thiourea dioxide, lithium aluminum hydride An aqueous solution containing boron-based reducing agents (sodium borohydride, dimethylamine borane, diethylamine borane, triethylamine borane, etc.) can be exemplified.

  Examples of the acid salt having sulfur in the molecule used in the present invention described in the above (C) include sulfites, thiocyanates, thiosulfates, and sulfates.

  Examples of the sulfites include sulfites, pyrosulfites, and hydrogen sulfites, and alkali metal salts, alkaline earth metal salts, ammonium salts, and the like can be widely used. It is preferable that the solubility in water is higher. Specifically, an aqueous solution containing lithium sulfite, potassium sulfite, sodium sulfite, ammonium sulfite, potassium hydrogen sulfite, sodium hydrogen sulfite, ammonium hydrogen sulfite, sodium pyrosulfite, etc. may be exemplified. I can do it.

  As thiocyanates, alkali metal salts, alkaline earth metal salts, ammonium salts, and the like of thiocyanic acid can be used. Higher solubility in water is preferred, and specific examples include aqueous solutions containing potassium thiocyanate, sodium thiocyanate, calcium thiocyanate, ammonium thiocyanate, and the like.

  As the thiosulfates, alkali metal salts, alkaline earth metal salts, ammonium salts, and the like of thiosulfuric acid can be widely used. Higher solubility in water is preferable, and specific examples include aqueous solutions containing potassium thiosulfate, sodium thiosulfate, calcium thiosulfate, ammonium thiosulfate, and the like.

  As sulfates, alkali metal salts, alkaline earth metal salts and ammonium salts of sulfuric acid can be widely used. Higher solubility in water is preferable, and specific examples include aqueous solutions containing sodium sulfate, potassium sulfate, ammonium sulfate and the like.

  The dicarboxylic acid having 3 or more carbon atoms used in the present invention described in the above (D) is preferably one having high solubility in water, and preferably 8 or less in terms of solubility. Specific examples include aqueous solutions containing malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, malic acid, tartaric acid, citraconic acid, itaconic acid, mesaconic acid, and the like.

  The compounds described in (A) to (D) above may be used as a mixture. The concentration of the aqueous solution in which these compounds are dissolved is preferably 1% by mass or more, more preferably 10% by mass. %, And the upper limit is limited by solubility. A higher concentration is preferable because the conductivity can be further improved. Moreover, since the one where the temperature of aqueous solution and a solution can improve electroconductivity more is preferable, 60 degreeC or more is preferable, More preferably, it is 70 degreeC or more, and an upper limit is the boiling point of the aqueous solution containing the compound.

  In the present invention, the contact with the aqueous solution means that the solution or the aqueous solution is adhered to the coating (Z), or the coating (Z) is immersed in the solution or the aqueous solution. Thereby, it can be set as the silver film which has electroconductivity. The contact time is preferably 1 second or longer, and more preferably 10 seconds or longer. There is no particular upper limit, but 10 minutes or less is preferable in consideration of productivity. Furthermore, exposure to a high humidity environment for a short time is also effective for improving conductivity, and the temperature is preferably 10 ° C. to 80 ° C., and the weight absolute humidity H is 0.01 kg / kg D.P. A. It is preferable that there is more. Moreover, after making it contact with aqueous solution, it is preferable to wash | clean with water.

  Among these methods, from the viewpoint of the obtained conductivity, (1) the method of contacting the coating (Z) with an aqueous solution containing an inorganic salt of chlorine or bromine in the method A, (2) in the treating method of C, More preferred are a method of bringing the coating (Z) into contact with an aqueous solution containing sulfites or thiosulfates, and (3) a method of bringing the coating (Z) into contact with an aqueous solution containing oxydicarboxylic acids in the treatment method of D. Preferably, the contact is with an aqueous solution in which a plurality of substances selected from these substance groups are dissolved.

  The second method is to apply a coating obtained by applying and drying a silver ultrafine particle-containing composition containing at least an ultrafine silver particle having an average particle size of 0.1 μm or less, a polymer latex, and a water-soluble halide in an aqueous medium. In this method, a silver film is formed by treatment by ultraviolet irradiation and / or re-application of moisture.

As content of polymer latex and water-soluble halide, following formula 2.93 <A / B <168
A: Solid concentration of polymer latex in the composition containing ultrafine silver particles (unit: mass%)
B: Molar concentration of water-soluble halogenated substance (unit: mol / kg)
Is preferably satisfied. Here, the molar amount of water-soluble halide is the amount of water-soluble halide obtained by subtracting the mass of solutes such as silver, polymer latex solids, and water-soluble halides from the total mass of the silver ultrafine particle-containing composition. Means the value divided by the value.

  When A / B does not satisfy the above formula, that is, when the content of either the polymer latex or the water-soluble halide is excessive, the conductivity of the formed silver film may be lowered. Further, when the content of the water-soluble halide is excessive, the dispersion stability of the silver ultrafine particle-containing composition may be lowered.

  For the ultraviolet rays used in the present invention, it is generally preferable to use a near ultraviolet region having a wavelength of 180 to 400 nm as a light source. For example, visible light (wavelength 400 to 500 nm) in a blue or purple region other than this region can be used in combination.

  Examples of the light source of near-ultraviolet light having a wavelength of 180 to 400 nm and blue and purple light having a wavelength of 400 to 500 nm include a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, and a chemical lamp. Mercury-xenon lamp, excimer lamp, short arc lamp, helium-cadmium laser, argon laser, excimer laser, UV electrodeless lamp, and the like. For example, the atomic beam of mercury shows emission lines at 184.9 nm, 253.7 nm, 365.0 nm, and 435.8 nm. It is also possible to use sunlight as the light source.

  In addition, although an electron beam can be used instead of ultraviolet rays, ultraviolet rays are preferably used in the present invention because the apparatus is simple and the equipment cost may be low.

  As a method of re-applying moisture in the second method, for example, (1) a method described later as an application method of the silver ultrafine particle-containing composition is applied, and water is applied. (2) A mist water by a spray nozzle And (3) exposure to a high humidity environment. In the case of (3), the temperature is preferably 10 ° C. to 80 ° C., and the absolute humidity H is 0.01 kg / kg D.D. A. It is preferable that there is more.

  Moreover, after forming a silver film by ultraviolet irradiation and / or re-application of moisture, it is preferable to perform washing with water. In addition, the silver ultrafine particle-containing composition is applied and dried, and the silver film and the silver film can be obtained by using the methods (A) to (D) in the first method described above, instead of ultraviolet irradiation and / or re-application of moisture. The same is true for conductivity.

  In this invention, the base material 1 is not specifically limited, The well-known glass base material and plastic base material of a light transmittance can be used. In a resistive film type touch panel, since a portion to be touched requires mobility, it is preferable to use a plastic base material that is made into a film and has flexibility.

Any glass substrate that is generally used as glass for a substrate can be used. For example, soda lime glass, non-alkali glass, quartz glass and the like can be exemplified.

  Examples of the plastic substrate include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polymethyl methacrylate (PMMA), polymethacrylate, polyacrylate, polyolefins such as polyethylene and polypropylene, Polyether sulfone, cellophane, vinyl chloride, polyvinyl chloride, vinylidene chloride, polystyrene, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, nylon, polyimide (PI), polyamide, aramid, polycarbonate (PC), triacetyl cellulose, polycarbonate Examples include plastic substrates made of acetylcellulose, cellulose resin, acrylic resin, urethane resin, etc. . The film is formed by a melt extrusion method or a solution casting method.

  In the present invention, the material for forming the transparent conductive film 2 is not particularly limited as long as it has conductivity and can form a transparent film, and a known material for forming a transparent conductive film can be used. Examples thereof include an indium oxide film doped with tin (ITO film), a tin oxide film doped with fluorine (FTO film), and a zinc oxide film doped with antimony. Among these, ITO is preferably used because of its high transparency and excellent conductivity.

  The method for forming the transparent conductive film 2 is not particularly limited, and can be formed by a known method. Examples include, but are not limited to, sputtering, electron beam evaporation, ion plating, chemical vapor deposition, and nanoparticle printing / coating. The transparent conductive film 2 may be formed on the entire surface of the substrate 1, but may be formed up to a part of the frame portion, that is, a portion connected to the wiring structure.

In the present invention, in order to form a conductive member for a touch panel, it is necessary to form a structure having a patterned transparent conductive film 2 and wiring 3 electrically coupled to the transparent conductive film 2 as necessary. The following examples can be given as a method of forming this.
1. A wiring pattern made of the composition containing silver ultrafine particles is printed on the frame portion 12 of the base material 10 having the transparent conductive film 11 patterned as necessary, and then a silver film is formed by the above treatment to form a wiring structure. how to.
2. A solid-like printing or coating made of a composition containing ultrafine silver particles is applied to the frame portion 12 of the base material 10 having the transparent conductive film 11 patterned as required, dried to form a film, and then etched or laser ablated. A method of forming a wiring structure by patterning and forming a silver film by the above treatment.
3. A solid-like printing or coating made of a composition containing silver ultrafine particles is performed on the frame portion 12 of the base material 10 having the transparent conductive film 11 patterned as necessary, and after drying, a silver film is formed by the above-described treatment, A method of patterning this silver film by etching or laser ablation to form a wiring structure.
4). A solid-like printing or coating made of a composition containing ultrafine silver particles is applied to the frame portion 12 of the substrate 10 having the transparent conductive film 11, and after drying, it is patterned by etching or laser ablation, and a silver film is formed by the above treatment. A method of simultaneously forming a patterned transparent conductive film and a wiring structure as needed.
5. A solid-like printing or coating made of a composition containing ultrafine silver particles is applied to the frame portion 12 of the base material 10 having the transparent conductive film 11, and after drying, a silver film is formed by the above treatment, and patterned by etching or laser ablation. A method of simultaneously forming a patterned transparent conductive film and a wiring structure as needed.

  In the present invention, any of the methods 1 to 5 can be suitably used. For example, a resistive film type touch panel having a matrix-like transparent conductive film capable of multipoint detection, a capacitive type touch panel, etc. In the case of using a patterned transparent conductive film, it is preferable to use the method 4 or 5 from the viewpoint of yield and manufacturing efficiency.

  In the first method, as a method of establishing electrical coupling between the transparent conductive film 11 and the formed wiring structure, a connection portion (pad area) to the wiring structure is provided in advance in the transparent conductive film, A method of forming the portion so as to overlap the connection portion can be exemplified.

  When etching is used for patterning by the method 2 or 3, it is necessary to protect the transparent conductive film 11 during etching. For this, a protective film may be bonded, but after forming a film of silver ultrafine particle-containing composition or a processed silver film on the frame portion 12, a negative type dry film having ultraviolet curability is used. It is preferable that an unexposed resist layer formed by bonding or liquid resist coating and drying is provided on the entire surface on the transparent conductive film side, irradiated with ultraviolet rays from the back surface, and self-patterned to form a cured resist layer. This is because the film of the ultrafine silver particle-containing composition or the processed silver film has an optical density and therefore acts as a mask during exposure.

  In the present invention, the silver ultrafine particle-containing composition is applied to the frame portion 12 by a known printing method such as gravure printing, flexographic printing, ink jet printing, screen printing, offset printing, gravure offset printing, dispenser printing, pad printing, and the like. The patterned wiring structure is printed or solidly applied. Alternatively, it is applied to the frame portion 12 in a solid manner by a known coating method such as rod bar coating, slit die coating, or ink jet coating. Further, before printing and coating, surface modification can be performed by a known method such as corona discharge, UV irradiation, or atmospheric pressure plasma.

  The applied silver ultrafine particle-containing composition is dried to form a film. It does not specifically limit as a drying method. When performing hot air drying, the temperature and dew point of the hot air are determined from the viewpoint of the drying speed, the heat resistance of the substrate, and the like. Moreover, you may dry by a near infrared ray, a far infrared ray, and an ultraviolet-ray, and especially the drying by an ultraviolet-ray can be combined with the ultraviolet irradiation required for the 2nd method mentioned above. Since it is only necessary to evaporate volatile components such as water, it can be dried in a short time of about several tens of seconds.

  Patterning by etching of a silver ultrafine particle-containing composition film or a processed silver film is performed by forming a resist layer by various known photolithography and direct printing, and using ferric nitrate aqueous solution or phosphoric acid and nitric acid. It is preferable to use a known silver etching solution such as a mixed acid solution.

  The patterning of the transparent conductive film 11 includes a method of forming and etching a resist layer by various photolithography and direct printing, a method of removing unnecessary parts by a dry process such as laser ablation, and a method of forming nanoparticles forming a transparent conductive film It is performed by a known method such as a method of patterning and printing. For example, for an ITO film, wet etching using a ferric chloride / hydrochloric acid aqueous solution or dry etching using a gas containing hydrogen iodide (HI) can be used as an etching method.

  When etching is used for patterning by the method 4 or 5, the transparent conductive film and the silver film may be separately etched, but it is more preferable to etch both simultaneously. For example, an ITO film and a silver film can be exemplified by an aqueous cerium sulfate solution and an aqueous cerium nitrate solution. As a commercially available product, Myclean (manufactured by Chugai Photo Chemical Co., Ltd.), which is a mixed aqueous solution of ammonium sulfate, cerium sulfate, and sulfuric acid, can be mentioned.

  The conductive member for a touch panel can be manufactured by the method described above. Moreover, since this invention can perform formation of a wiring structure rapidly, it can be used especially suitably in the touch-panel manufacturing process by roll-to-roll. Moreover, you may provide the transparent conductive film 11 and the wiring structure on both surfaces of a base material.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.

Example 1
<Preparation of silver ultrafine particle dispersion 1>
To a 10 L stainless beaker, 272 g of roasted dextrin (manufactured by Nissho Chemical Co., Ltd., dextrin No. 3) and 4300 g of pure water were added and dissolved by stirring for about 30 minutes. Thereafter, 659 g of silver nitrate was added and dissolved by stirring for about 30 minutes. This solution was cooled to about 5 ° C. in an ice bath, a 10 ° C. solution in which 304.5 g of potassium hydroxide was dissolved in 419.5 g of pure water was added, and the reduction reaction was performed for 1 hour while stirring in the ice bath. Went. Acetic acid was added to the resulting solution to adjust to pH = 5.6, 1 g of Biozyme F10SD (manufactured by Amano Enzyme) was added, and the mixture was stirred at 45 ° C. for 1 hour. Next, after the obtained ultrafine silver particle dispersion was purified by a centrifugal separation method, pure water was added and redispersed so that the silver concentration was 45% by mass, and 800 g of ultrafine silver particle dispersion 1 was obtained. The silver ultrafine particles contained had an average particle diameter of 20 nm and a yield of 86%.

<Preparation of silver ultrafine particle-containing composition 1>
200 g of the ultrafine silver particle dispersion 1 was taken and 27 g of U-coat UWS-145 (polyurethane latex, average particle size 0.02 μm, solid content 35% by mass) manufactured by Sanyo Chemical Industry Co., Ltd. was added as a polymer latex. An agent, pure water, and ethylene glycol were added to obtain a silver ultrafine particle-containing composition 1 having a silver concentration of 30% by mass, a surface tension of 30 mN / m, and a viscosity of 9 mPa · s.

<Production of conductive members 1 and 2 for touch panel>
An ITO film having a thickness of 0.1 μm and a tin oxide content of 8% by mass is formed by high-frequency magnetron sputtering using an indium-tin composite oxide as a target on the entire surface of a PET film substrate having a size of 10 cm × 10 cm and a thickness of 100 μm. A film was formed. Next, the silver ultrafine particle-containing composition 1 was printed by flexographic printing as shown in 21 of FIG. 3, dried with warm air, then immersed in a 3N sodium chloride aqueous solution at 80 ° C. for 30 seconds, washed with water and dried. A silver film was formed on the frame portion. The time required for forming the silver film was 2 minutes. A negative dry film was bonded thereto, and exposure and etching were performed to produce a touch panel conductive member 1 having the pattern 31 of FIG. 4 and a touch panel conductive member 2 having the pattern 32 of FIG. . The wiring width was 80 μm.

<Production of touch panel 1>
The obtained conductive films 1 and 2 for the touch panel were bonded with an EVA adhesive so that the ITO films face each other to obtain a laminated film. A double-sided FPC was connected to the electrode extraction portion using ACF and connected to an external circuit.

Example 2
<Preparation of silver ultrafine particle-containing composition 2>
200 g of the silver ultrafine particle dispersion 1 was taken, and 48 g, 1.2 mass of U-coat UWS-145 (polyurethane latex, average particle size 0.02 μm, solid content 35 mass%) manufactured by Sanyo Chemical Industries Co., Ltd. was used as the polymer latex. An aqueous sodium chloride solution having a concentration of 130%, surfactant, pure water, and ethylene glycol were further added to obtain a silver ultrafine particle-containing composition 2 having a silver concentration of 30% by mass, a surface tension of 30 mN / m, and a viscosity of 9 mPa · s.

<Production of conductive members 3 and 4 for touch panel>
An ITO film having a thickness of 0.1 μm and a tin oxide content of 8% by mass is formed by high-frequency magnetron sputtering using an indium-tin composite oxide as a target on the entire surface of a PET film substrate having a size of 10 cm × 10 cm and a thickness of 100 μm. A film was formed. Next, the silver ultrafine particle-containing composition 1 was printed by flexographic printing as shown in 21 of FIG. 3, dried with warm air, and then irradiated with ultraviolet rays (having 253.7 nm and 365.0 nm emission lines) of 1.1 J / m ² irradiation, and exposure for 1 minute under the condition of 60 ° C. and 90% Rh (weight absolute humidity H = 0.133 kg / kg DA) to form a silver film on the frame, and further washing with water and drying Went. The time required for forming the silver film was 4 minutes. By bonding a negative dry film to this, and performing exposure and etching, the conductive member 3 for the touch panel having the pattern 31 in FIG. 4 and the conductive member 4 for the touch panel having the pattern 32 in FIG. 4 were produced. . The wiring width was 80 μm.

<Production of touch panel 2>
Bonding was performed with an EVA adhesive so that the ITO films of the obtained conductive members 3 and 4 for the touch panel face each other to obtain a laminated film. A double-sided FPC was connected to the electrode extraction portion using ACF and connected to an external circuit.

Example 3
<Production of conductive members 5 and 6 for touch panel>
An ITO film having a thickness of 0.1 μm and a tin oxide content of 8% by mass is formed by high-frequency magnetron sputtering using an indium-tin composite oxide as a target on the entire surface of a PET film substrate having a size of 10 cm × 10 cm and a thickness of 100 μm. A film was formed. A negative dry film was bonded thereto, and exposure and etching were performed to produce an ITO film having the pattern 41 in FIG. 5 and an ITO film having the pattern 42 in FIG. Next, the pattern 51 of FIG. 6 and the pattern 52 of FIG. 6 are printed on the composition 1 containing silver ultrafine particles using flexographic printing, the same processing as in Example 1 is performed, and the touch panel having the pattern 31 of FIG. The conductive member 5 and the conductive member 6 for touch panels which have the pattern 32 of FIG. 4 were produced. The wiring width was 80 μm.

<Production of touch panel 3>
The obtained conductive films 5 and 6 for the touch panel were bonded with an EVA adhesive so that the ITO films face each other to obtain a laminated film. A double-sided FPC was connected to the electrode extraction portion using ACF and connected to an external circuit.

《Comparative example》
<Production of conductive members 7 and 8 for touch panel>
An ITO film having a thickness of 0.1 μm and a tin oxide content of 8% by mass is formed by high-frequency magnetron sputtering using an indium-tin composite oxide as a target on the entire surface of a PET film substrate having a size of 10 cm × 10 cm and a thickness of 100 μm. A film was formed. A negative dry film was bonded thereto, and exposure and etching were performed to produce an ITO film having the pattern 41 in FIG. 5 and an ITO film having the pattern 42 in FIG. Next, a commercially available resin-type silver paste DW-260H-1 (manufactured by Toyobo Co., Ltd.) was used, using a screen plate with a permeation volume of 10 cc / m ² and a 350 mesh, pattern 51 in FIG. 6 and pattern 52 in FIG. After being printed and dried with warm air, heat curing is performed at 120 ° C. for 30 minutes to form a wiring structure in the frame portion, and the conductive member 7 for a touch panel having the pattern 31 of FIG. 4 and the pattern 32 of FIG. A conductive member 8 for a touch panel having the above was produced. The wiring width was 80 μm.

<Production of touch panel 4>
The obtained conductive films 7 and 8 for the touch panel were bonded with an EVA adhesive so that the ITO films face each other to obtain a laminated film. A double-sided FPC was connected to the electrode extraction portion using ACF and connected to an external circuit.

<Evaluation of wiring resistance>
The resistance values of the wiring structure portions of the conductive members 1 to 6 for the touch panel before the touch panel was manufactured were measured. The length to be measured was 50 mm. As a result, the conductive members 1 and 2 for the touch panel were about 150Ω, and the conductive members 3 and 4 for the touch panel were about 100Ω, and the resistance value was stable with no difference depending on the measurement location. The touch panel conductive members 5 and 6 were about 150Ω to 180 ohms, and a slight variation in resistance value was also observed. The touch panel conductive members 7 and 8 had a high resistance value of about 300Ω to 500Ω, and variation in the resistance value was also observed.

<Evaluation of touch panel>
About the produced touch panels 1 to 4, it connected with the external touch position detection circuit (driver), and performed the input test. As a result, in the touch panels 1 and 2 of the present invention, no position detection error was observed, and the touch panel 3 of the present invention was within an allowable range although a position detection error was observed. In contrast, the touch panel 4 of the comparative example has a position detection error.

  As is clear from the above results, it can be seen that the conductive members 1 to 6 for the touch panel according to the present invention can form a silver film for forming the wiring structure in a short time, and thus the manufacturing efficiency is high. It can be seen that the conductive members 7 and 8 for the touch panel of the comparative example take time for heat curing and have low manufacturing efficiency. In addition, since the touch panel 1 and 2 of the present invention have low and stable wiring resistance values, no position detection error is observed, but the comparative touch panel 4 has high wiring resistance values and variations. It can be seen that there is an error in position detection and the performance of the touch panel is inferior.

(1) Base material (2) Transparent conductive film (3) Wiring (10) Base material (11) ITO film (12) Frame portion (21) Print portion (31) Pattern (32) Pattern (41) Pattern (42) Pattern (51) Pattern (52) Pattern

Claims (2)

A method for manufacturing a conductive member for a touch panel, wherein a part of a wiring structure formed in a frame portion of the touch panel contains silver ultrafine particles having an average particle size of 0.1 μm or less and a polymer latex in an aqueous medium. A silver film formed by treating the coating (Z) obtained by applying and drying the silver ultrafine particle-containing composition by the method described in (A) to (D) below, or at least an average particle in an aqueous medium A coating obtained by applying and drying a composition containing ultrafine silver particles having a diameter of 0.1 μm or less, a polymer latex and a water-soluble halide, and drying is treated by irradiation with ultraviolet rays and / or re-application of moisture. A method for producing a conductive member for a touch panel, characterized by comprising a silver film formed.
(A) Contact between an aqueous solution containing a halogen inorganic salt and the coating (Z).
(B) Contact between an aqueous solution containing a reducing compound capable of reducing silver ions and the coating (Z).
(C) Contact between an aqueous solution containing an acid salt having a sulfur atom in the molecule and the coating (Z).
(D) Contact between an aqueous solution containing a dicarboxylic acid compound having 3 or more carbon atoms and the coating (Z).   The method for manufacturing a conductive member for a touch panel according to claim 1, wherein the wiring structure formed in the frame portion of the touch panel is patterned by etching.

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