JP2012089718A - Method of producing conductive material and conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a conductive material having good storage stability, and to provide a conductive material.SOLUTION: In the method of producing a conductive material, a conductive pattern is formed by printing or applying a composition containing ultra-fine metal particles on the porous layer of a substrate for forming a conductive pattern that has a porous layer composed of fine particles and a resin binder on a support. Subsequently, the surface of the substrate for forming a conductive pattern on the side having the porous layer is filled with a resin entirely or partially.

Description

  The present invention relates to a method for producing a conductive material having good storage stability, and a conductive material.

  In recent years, printed electronics using ink or paste containing ultrafine metal particles has attracted attention.

  When producing a conductive material having a conductive pattern by printing, conventionally a high viscosity conductive resin paste containing silver powder, a resin binder and an organic solvent is used, and a printing method suitable for a high viscosity paste such as a screen printing method is used. It was patterned. However, in recent years, there have been many attempts to pattern ink or paste containing ultrafine metal particles by inkjet printing because there are few applicable printing methods and it is difficult to print fine lines due to the large size of silver powder. Has been made. In addition, since the ultrafine metal particles are coated with a dispersant, the pattern formed may not have sufficient conductivity by simply applying and drying, and the dispersant may be used to develop sufficient conductivity. In order to volatilize and fuse the ultrafine metal particles, sintering at about 200 ° C. is required. In addition, many studies using an inexpensive polyethylene terephthalate film as a base material have been made, and silver metal ultrafine particles that can be sintered at a temperature of 150 ° C. or less at which the polyethylene terephthalate film does not soften are demanded.

  As a method for producing such ultrafine metal particles that can be sintered at a low temperature of 150 ° C. or lower, for example, Japanese Patent Application Laid-Open No. 2002-338850 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2005-81501 (Patent Document 2). A method is disclosed.

  Conventionally, not only glass and ceramics but also various films such as polyethylene terephthalate film, polyethylene naphthalate film, polyimide film, polycarbonate film, etc. are used as the conductive pattern forming substrate. It is difficult to cope with pattern miniaturization, and substrates obtained by processing these substrates are also disclosed. For example, in Japanese Patent Application Laid-Open No. 2003-229653 (Patent Document 3), an aggregation promoting layer made of inorganic oxide fine particles is previously provided on the lower side of a metal ultrafine particle layer, and when the metal ultrafine particle solution is applied, the lower inorganic layer A base material for forming a conductive pattern that can promote aggregation of metal ultrafine particles by allowing a solvent to selectively penetrate mainly into pores formed by oxide fine particles is disclosed. In Japanese Patent Application Laid-Open No. 2008-4375 (Patent Document 4) and Japanese Patent Application Laid-Open No. 2008-235224 (Patent Document 5), it is possible to obtain very high conductivity without heating ultrafine metal particles. As a pattern forming substrate, a conductive pattern forming substrate having a porous layer containing a compound having a halogen in the molecule by an ionic bond, a reducing substance, or the like is disclosed. In JP 2009-21153 A (Patent Document 6) and JP 2009-104807 A (Patent Document 7), it is possible to obtain high conductivity safely and quickly without heating ultrafine metal particles. As a property development method, after forming a pattern using metal ultrafine particles on a substrate having a porous layer composed of inorganic fine particles and a resin binder, sulfites, thiosulfates, thiocyanates, chromates, carbon number 3 An electroconductivity expression method using the above dicarboxylic acid is disclosed. Further, in JP 2010-165997 A (Patent Document 8), as a substrate for forming a conductive pattern, which has high adhesion to the substrate of the conductive pattern, little bleeding, and excellent conductivity can be obtained. A substrate for forming a conductive pattern having a porous layer made of fine particles and a resin binder and a layer mainly composed of a resin on the porous layer is disclosed.

  On the other hand, a conductive pattern that has been exposed to the atmosphere for a long time has a problem in that corrosion occurs due to chemical components in the atmosphere and the conductivity of the pattern decreases. For example, in the case of a conductive pattern made of silver, the conductivity of the pattern decreases with time due to corrosion by ozone, hydrogen sulfide, sulfur dioxide, etc. in the atmosphere.

  Further, when the conductive pattern forming substrate having the porous layer is used as described above, the formed conductive pattern is necessarily present on the porous layer, and therefore the pattern is the front and back. And it will be affected by the atmosphere from the side. Therefore, compared to a conductive pattern that does not exist on the porous layer, there is a problem that it is more easily affected by chemical components contained in the atmosphere, and the conductivity of the pattern is likely to decrease.

  A method for suppressing corrosion by sealing the surface of a conductive pattern is generally well known. As the suppression method, for example, Patent Documents 4 to 7 described above include a resin component as a method for protecting a conductive member. A method of applying to the surface of the member is described. Japanese Patent Laid-Open No. 2007-109915 (Patent Document 9) discloses a light emitting diode in which an epoxy resin cured with a polythiol-based curing agent is provided on a metal surface as a protective film, and Japanese Patent Laid-Open No. 2010-7013 (Patent Document). 10) discloses a metal surface coating material and a metal surface protection method in which a silane compound and a polymer containing a structural unit derived from vinyl alcohol are mixed. However, for satisfactory protection of the conductive pattern formed on the porous layer, simultaneous protection of the front and back surfaces and the side surfaces is indispensable as described above, and the above-described protection method is not sufficiently satisfactory.

JP 2002-338850 A JP 2005-81501 A JP 2003-229653 A JP 2008-4375 A JP 2008-235224 A JP 2009-21115 A JP 2009-104807 A JP 2010-165997 A JP 2007-109915 A JP 2010-7013 A

  An object of the present invention is to provide a method for producing a conductive material from which a conductive material having good storage stability is obtained, and a conductive material having good storage stability.

The above object of the present invention has been basically achieved by the following invention.
1. A conductive pattern is formed by printing or applying a composition containing metal ultrafine particles on a porous layer of a conductive pattern forming substrate having a porous layer composed of fine particles and a resin binder on a support, and thereafter A method for producing a conductive material, characterized in that a resin is filled in the entire surface or a part of a surface having a porous layer of a substrate for forming a conductive pattern.
2. A conductive material obtained by the production method according to 1 above.

  According to the present invention, it is possible to provide a method for producing a conductive material with good storage stability and a conductive material with good storage stability.

  Hereinafter, the present invention will be described in detail.

  The inventors of the present invention have a conductive property by printing or applying a composition containing metal ultrafine particles to a porous layer of a conductive pattern forming substrate having a porous layer composed of fine particles and a resin binder on a support. Protecting the conductive pattern, all of its front and back and sides, by forming a pattern and then filling the entire or part of the surface with the porous layer of the substrate for forming a conductive pattern with resin. Thus, the inventors have found that a conductive pattern having extremely good storage stability can be obtained. That is, the present invention is a method for producing a conductive material that realizes protection of all of the front and back surfaces and side surfaces of a conductive pattern by a very simple method.

  The substrate for forming a conductive pattern in the present invention has a porous layer made of fine particles and a resin binder formed on a support. Moreover, you may provide a porous layer in both surfaces of a support body as needed.

  The porous layer plays a role of quickly absorbing the dispersion medium contained in the composition containing ultrafine metal particles, thereby suppressing bleeding and repellency of the printed or coated conductive pattern. In the case of ink or paste that tends to spread and spread, erroneous connection (so-called bridge) between wirings due to bleeding can be suppressed, and conversely, in the case of ink or paste that does not spread easily and wet, breakage due to repelling can be suppressed.

  The support in the present invention is not particularly limited. Polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, polyarylate, polysulfone, poly Various kinds of acrylic resins such as ether sulfone, polyimide, fluororesin, phenoxy resin, triacetyl cellulose, polyethylene terephthalate, polyphenylene sulfide, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, cellophane, nylon, polystyrene resin, ABS resin, etc. Various films made of resin, quartz glass, alkali-free glass, crystallized transparent glass, Pyrex (registered trademark) and other glass, paper, nonwoven fabric, cloth, various metals, various ceramics, etc. You can gel. Further, these supports can be appropriately combined depending on the application. For example, a flexible printed circuit board material obtained by laminating copper foil and polyimide, or a polyolefin resin-coated paper obtained by laminating paper and a polyolefin resin can be used. Furthermore, an object molded into a three-dimensional shape using these resins or the like can also be used as a support.

  Among these, from the viewpoint of cost and versatility, a support made of paper, polyolefin resin-coated paper, polyethylene, polypropylene, triacetylcellulose, polyethylene terephthalate, or polycarbonate is preferable.

  Among the above-mentioned supports, in the case of using a non-absorbent support such as a film made of various resins, glass, polyolefin resin-coated paper, etc., the coating property of the coating liquid for forming the porous layer and the support of the porous layer In order to improve the adhesion to the body, it is preferable to provide a known undercoat layer made of gelatin, various urethane resins, polyvinyl alcohol or the like between the support and the porous layer. Further, for example, a polyethylene terephthalate film is commercially available with an undercoat layer provided in advance as an easy adhesion treatment product, and this may be used. Further, the surfaces of these supports may be subjected to surface treatment such as corona treatment or plasma treatment.

When the undercoat layer is provided, the solid content coating amount is 0.5 g / m ² or less, preferably 0.3 g / m ² or less, and more preferably 0.1 g / m ² or less.

  The porous layer of the present invention means a layer containing fine particles and 80% by mass or less of a resin binder with respect to the fine particles. As fine particles used, known fine particles can be widely used. For example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, Amorphous synthetic silica, colloidal silica, alumina, colloidal alumina, alumina hydrate, lithopone, zeolite, hydrous halloysite, magnesium hydroxide and other inorganic fine particles, acrylic or methacrylic resin, vinyl chloride resin, vinyl acetate resin, Polyester resin, styrene / acrylic resin, styrene / butadiene resin, styrene / isoprene resin, methyl methacrylate / butyl methacrylate resin, polycarbonate resin, silicone resin, urea resin, Ramin resins, epoxy resins, phenolic resins, the spherical or irregular comprising at least one or more resins such as diallyl phthalate resin, non-porous or porous organic fine particles may be mentioned of. Moreover, it is also possible to use a mixture of one or more inorganic fine particles and one or more organic fine particles. Among the above-mentioned fine particles, it is preferable to use inorganic fine particles from the viewpoint of absorbability such as water and high boiling point solvent contained in the ultrafine metal particle-containing composition. Light calcium carbonate, heavy calcium carbonate, kaolin, talc, magnesium carbonate Amorphous synthetic silica, alumina, and alumina hydrate are more preferable, and amorphous synthetic silica, alumina, and alumina hydrate are particularly preferable because a porous layer having a denser structure can be formed. Furthermore, the average secondary particle diameter of these inorganic fine particles is preferably 500 nm or less, and the more preferable average secondary particle diameter of the inorganic fine particles is 10 to 300 nm, and further 20 to 200 nm. In addition, when the substrate is required to be flexible, it is particularly preferable to use alumina hydrate.

  The porous layer may be composed of a plurality of layers. The layer close to the support is made of inexpensive inorganic fine particles such as light calcium carbonate, heavy calcium carbonate, kaolin and talc, and the layer far from the support is used. A layer using amorphous synthetic silica, alumina, or alumina hydrate may be provided.

  Amorphous synthetic silica preferably used in the present invention can be roughly classified into wet method silica, gas phase method silica, and others depending on the production method.

  Wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through filtration, water washing, drying, pulverization and classification. Precipitated silica is commercially available, for example, as a nip seal from Tosoh Silica Co., Ltd., as Toku Seal from Tokuyama Co., Ltd., and as a fine seal, as Mizukasil from Mizusawa Chemical. Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During the ripening, the fine particles dissolve and reprecipitate so as to bind other primary particles, so that the distinct primary particles disappear and form relatively hard aggregated particles having an internal void structure. For example, it is commercially available from Tosoh Silica Co., Ltd. as nip gel, from Grace Japan Co., Ltd. as syloid and silo jet, and from Mizusawa Chemical Industry Co., Ltd. as Mizukasil. The sol method silica is also called colloidal silica, and is obtained by heating and aging silica sol obtained through metathesis of sodium silicate acid or the like through an ion exchange resin layer, and is commercially available as, for example, Snowtex from Nissan Chemical Industries, Ltd. .

  In the present invention, wet process silica pulverized to an average secondary particle diameter of 500 nm or less can be preferably used. As the wet method silica used here, precipitation method silica or gel method silica is preferable, and precipitation method silica is particularly preferable. The wet process silica particles used in the present invention are preferably wet process silica particles having an average primary particle diameter of 50 nm or less, preferably 3 to 40 nm, and an average aggregate particle diameter of 5 to 50 μm. It is preferable to use wet method silica fine particles finely pulverized to an average secondary particle diameter of 500 nm or less, preferably about 10 to 300 nm, more preferably about 20 to 200 nm in the presence of. By finely pulverizing the average secondary particle diameter to 500 nm or less, the pore diameter in the formed porous layer becomes finer than in the case where fine pulverization is not performed. The state is less likely to be obtained, and the resulting conductivity is improved. As the pulverization method, a wet dispersion method of mechanically pulverizing wet method silica dispersed in an aqueous medium is preferably used, and it is preferable to use a media mill such as a bead mill. The bead mill grinds the pigment by colliding with the beads filled in a sealed vessel. The Shinmaru Enterprises Co., Ltd. serves as a dyno mill, Asada Tekko Co., Ltd. as a Glen Mill, and Ashizawa Finetech Co., Ltd. ) And is commercially available as a star mill. After pulverization using a media mill or the like, it is preferable to further disperse using a pressure disperser such as a high-pressure homogenizer or an ultra-high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like.

  The average primary particle diameter as used in the present invention is an average particle diameter obtained by measuring the diameter of a circle equal to the projected area of each of the 100 primary particles existing within a certain area by observation with an electron microscope. It is. The average secondary particle diameter can be determined by photography using a transmission electron microscope. For simplicity, the number median diameter can be obtained using a laser scattering particle size distribution analyzer (for example, LA910, manufactured by Horiba, Ltd.). Can be measured as The average agglomerated particle diameter refers to the average particle diameter of wet silica supplied as a powder, and can be determined, for example, by a Coulter counter method.

  Vapor phase silica is also called a dry method as opposed to a wet method, and is generally made by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd.

The average primary particle diameter of the vapor phase silica used in the present invention is preferably 40 nm or less, and more preferably 15 nm or less. More preferably, an average primary particle diameter of 3 to 15 nm and a specific surface area by BET method of 200 m ² / g or more (preferably 250 to 500 m ² / g) are used.

  The BET method referred to in the present invention is one of powder surface area measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, as the adsorbed gas, a large amount of nitrogen gas is used, and the method of measuring the adsorbed amount from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller formula, called the BET formula, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  Even when vapor-phase process silica is used, it is preferable to disperse to an average secondary particle diameter of 500 nm or less, similarly to wet process silica. The average secondary particle diameter of the dispersed gas phase method silica is more preferably 10 to 300 nm, and still more preferably 20 to 200 nm. As a dispersion method, pre-mixing a dispersion medium mainly composed of gas phase silica and water by ordinary propeller stirring, turbine type stirring, homomixer type stirring, etc., and then a media mill such as a ball mill, a bead mill, a sand grinder, Dispersion is preferably performed using a pressure disperser such as a high-pressure homogenizer or an ultra-high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like.

  When producing a slurry of wet method silica or vapor phase method silica having an average secondary particle diameter of 500 nm or less, various known methods may be used in order to increase the concentration of the slurry and improve the dispersion stability. For example, a method of dispersing in the presence of an alkaline compound as described in JP-A Nos. 2002-144701 and 2005-1117, and a cationic method as described in JP-A-2001-19421 Examples include a method of dispersing in the presence of a compound, a method of dispersing in the presence of a silane coupling agent as described in JP-A-2006-110770, and a method of dispersing in the presence of a cationic compound. Is more preferable.

  Examples of the cationic compound used for the pulverization or dispersion of the above-mentioned wet method silica or gas phase method silica include polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, polymer having primary to tertiary amino groups and quaternary ammonium bases. Is preferably used. In particular, diallylamine derivatives are preferably used as the cationic polymer. In terms of dispersibility and dispersion viscosity, the molecular weight of these cationic polymers is preferably 2,000 to 100,000, and particularly preferably 2,000 to 30,000.

  As the alumina used in the present invention, γ-alumina which is a γ-type crystal of aluminum oxide is preferable, and among them, a δ group crystal is preferable. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particles of thousands to tens of thousands of nanometers are averaged by ultrasonic, high-pressure homogenizer, counter collision type jet crusher, etc. What grind | pulverized the particle diameter to 500 nm or less, Preferably about 20-300 nm can be used.

The alumina hydrate of the present invention is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The alumina hydrate is generally obtained by a known production method such as hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, hydrolysis of an aluminate. The average secondary particle diameter of the alumina hydrate used in the present invention is 500 nm or less, preferably 20 to 300 nm.

  The above-mentioned alumina and alumina hydrate used in the present invention are used in the form of a dispersion dispersed with a known dispersant such as acetic acid, lactic acid, formic acid, nitric acid and the like.

  In the present invention, examples of the resin binder used together with the fine particles constituting the porous layer include polyvinyl alcohols such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, and silyl-modified polyvinyl alcohol, oxidized starch, etherified starch, carboxymethylcellulose, hydroxy Examples of cellulose derivatives such as ethyl cellulose include casein, gelatin, soybean protein, conjugated diene copolymer latexes such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, and various types of these polymers. Aqueous adhesives such as functional group-modified polymer latex with functional group-containing monomers such as carboxyl groups, thermosetting synthetic resin systems such as melamine resin and urea resin, polymethyl methacrylate, polyurethane resin, Sum polyester resin, vinyl chloride - vinyl acetate copolymer, polyvinyl butyral, can be exemplified alkyd resin synthetic resin adhesive such as the like may be used alone or in combination. In addition, the use of known natural or synthetic resin binders alone or in combination is not particularly limited.

  Among these resin binders, polyvinyl alcohol or silanol-modified polyvinyl alcohol is preferable, and particularly preferable is partially saponified or completely saponified polyvinyl alcohol or silanol-modified polyvinyl alcohol having a saponification degree of 80% or more. The average degree of polymerization is preferably from 200 to 5,000.

  The content of the resin binder with respect to the fine particles is not particularly limited, but in order to form a porous layer using the fine particles, the content of the resin binder needs to be 80% by mass or less with respect to the fine particles. Is preferably in the range of 3 to 80% by mass, more preferably in the range of 5 to 60% by mass, and particularly preferably in the range of 10 to 40% by mass.

  In the present invention, if necessary, a hardening agent can be used together with the resin binder constituting the porous layer. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethyl) urea, 2-hydroxy-4,6-dichloro-1 , 3,5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, a compound having a reactive olefin as described in US Pat. No. 3,635,718, US Pat. N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,983,611 as described in US Pat. Aziridine compounds, carbodiimide compounds as described in US Pat. No. 3,100,704, US Pat. No. 3,091, Such epoxy compounds No. 37 described, such as dioxane derivatives of dihydroxy dioxane, borax, boric acid, there is an inorganic crosslinking agent such as boric acid salts, it can be used in combination thereof one or more. Although the usage-amount of a hardening agent is not specifically limited, 50 mass% or less is preferable with respect to a resin binder, More preferably, it is 40 mass% or less, Most preferably, it is 30 mass% or less.

  When using partially saponified or completely saponified polyvinyl alcohol or silanol-modified polyvinyl alcohol having a saponification degree of 80% or more as a resin binder, borax, boric acid, borates are preferable, and boric acid is particularly preferable. The amount used is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less, relative to polyvinyl alcohol.

  In general, the thickness (when dried) of the porous layer is preferably 1 to 100 μm, and more preferably 5 to 50 μm.

  The porous layer is prepared by dissolving or dispersing fine particles and resin binder or the like in an appropriate solvent to prepare a coating solution. The coating solution is a slide curtain method, slide bead method, slot die method, direct gravure roll method, reverse gravure roll. Pattern formation by coating method, spray method, air knife method, blade coating method, rod bar coating method, spin coating method, screen printing, inkjet printing, dispenser printing, offset printing, reverse offset printing, gravure printing, flexographic printing, etc. Etc., using various known coating or printing methods, it is possible to perform selective coating on the entire surface of the support or on a required site. In addition, after coating, the surface can be smoothed by performing a cast process that presses against a mirror roll, or the surface can be smoothed by performing a calendar process. Further, when the support is a three-dimensional body, screen printing corresponding to a dip method or a curved surface, tampo printing (also referred to as pad printing), or the like can be used.

  In the present invention, the ultrafine metal particle-containing composition is an ink or paste in which ultrafine metal particles are dispersed as a colloid in water and / or an organic solvent, and examples of the metal species include gold, silver, copper, and nickel. Can be illustrated. In particular, it is preferably made mainly of silver from the viewpoints of high conductivity, cost, productivity, ease of handling, and the like. Mainly consisting of silver means that the proportion of silver in the total ultrafine metal particles contained in the ultrafine metal particle-containing composition is at least 50% by mass, preferably the proportion of silver is at least 70% by mass, especially Preferably, it means 90% by mass or more.

  The average particle size of the ultrafine metal particles is required to be 0.1 μm or less, preferably 0.05 μm or less, from the viewpoint that the ultrafine metal particles maintain a stable dispersion state. The average particle diameter of the ultrafine metal particles can be obtained by observation under an electron microscope. Specifically, a metal ultrafine particle dispersion is applied 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.

  The content of the ultrafine metal particles contained in the ultrafine metal particle-containing composition in the present invention is preferably 1% by mass to 95% by mass, more preferably 3% by mass with respect to the total mass of the ultrafine metal particle-containing composition. To 90% by mass.

  The dispersion medium for the ultrafine metal particles used in the ultrafine metal particle-containing composition is water and / or an organic solvent. Examples thereof include water alone, a mixture of water and an organic solvent, and an organic solvent alone. As the composition of the mixture of water and organic solvent, as the organic solvent, water-soluble low-boiling solvents such as methanol, ethanol, isopropyl alcohol, acetone, ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, etc. Water-soluble high-boiling organic solvent can be added. As the constitution of only the organic solvent, alcohol-based high-boiling organic solvents such as ethylene glycol, diethylene glycol, propylene glycol and glycerin, ketone-based high-boiling organic solvents such as diacetone alcohol, isophorone and γ-butyllactone, 2-phenoxyethanol, ethylene Glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether and other glycol ether high boiling organic solvents, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, Diethylene glycol monoethyl ether acetate, die Ester-based high-boiling organic solvents such as lenglycol monobutyl ether acetate and ethoxyethoxyethyl acetate, aprotic amide-based high-boiling organic solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone, turpentine oil, α- Terpineol, mineral spirit, etc. are used.

  Ultrafine metal particles are evaporated in an inert gas, cooled and condensed by collision with the gas, recovered in a gas, a metal vapor synthesis method in which a metal is evaporated in a vacuum and recovered together with an organic solvent, laser irradiation Laser ablation method that evaporates and condenses in liquid by energy, chemical reduction method that reduces and generates and recovers metal ions in aqueous solution, method by pyrolysis of organometallic compound, metal chloride in gas phase Metal ultrafine particles produced by various known methods such as a method by reduction, a method of reducing oxides in hydrogen, a method using energy such as ultraviolet rays, ultrasonic waves, and microwaves can be preferably used.

  Various additives such as a thickener, an antistatic agent, an ultraviolet absorber, a plasticizer, a wetting agent, a surfactant, and a polymer binder may be added to the composition containing ultrafine metal particles depending on the purpose. By including an ultraviolet curable resin, it is possible to impart characteristics (ultraviolet curable characteristics) suitable for pattern formation by UV printing or UV inkjet method.

  In the present invention, the ultrafine metal particle-containing composition is adjusted in any form from a low-viscosity solution state to a high-viscosity paste state. Specifically, the viscosity, surface tension, size / content ratio of the ultrafine metal particles, and the like suitable for the method of applying ultrafine metal particles onto the substrate on which the conductive pattern is formed are adjusted. For example, when using gravure printing or an inkjet method, the viscosity is preferably adjusted to a range of 1 to 100 mPa · s, and when using relief printing or screen printing, it is adjusted to a range of 1 to 500 Pa · s. It is preferable.

  When adjusting to a high-viscosity paste state, it is difficult to obtain a desired viscosity only by increasing the concentration of ultrafine metal particles, and therefore it is preferable to add a polymer binder or a thickener. As the polymer binder, various known polymer binders such as cellulose resin, phenol resin, epoxy resin, acrylic resin, polyester resin, and polyimide resin can be used. As the thickener, various known thickeners such as hydroxylpropylcellulose, carboxymethylcellulose, pectin, polystyrene sulfonates, and polyacrylic acid can be used.

  As the composition containing ultrafine metal particles used in the present invention, colloids, inks or pastes containing ultrafine metal particles provided for forming a known or commercially available conductive pattern can be widely used. Moreover, since the manufacturing method is simple and the conductivity is excellent when the following conductivity enhancer is used, for example, Experiments in Colloid Chemistry, 1940, p. 19, Hauser, E .; A. and Lynn, J .; E. It is preferable to use ultrafine silver particles prepared using dextrin, as in the method described in 1).

  In the present invention, the metal ultrafine particle-containing composition is patterned by various printing methods or coating methods. For example, arbitrary linear pattern formation using a dispenser printing method capable of performing linear application, arbitrary linear or planar shape using various types of inkjet printing methods such as thermal, piezo, micro pump, static electricity, etc. Pattern formation, letterpress printing method, flexographic printing method, planographic printing method, intaglio printing method, gravure printing method, reverse offset printing method, sheet-fed screen printing method, rotary screen printing method, etc. Can be formed. In addition, various known coating methods such as gravure roll method, slot die method, spin coating method, etc. are used to form a pattern as a continuous surface on the entire surface or part of the conductive pattern forming substrate. The pattern is formed on the entire surface or part of the conductive pattern forming substrate using a tape or the like, or the composition containing metal ultrafine particles is attached to the entire conductive pattern forming substrate using the dipping method. It can also be made. More preferable printing methods include an inkjet printing method, a flexographic printing method, a gravure printing method, a reverse offset printing method, a sheet-fed screen printing method, and a rotary screen printing method.

  The ultrafine metal particle-containing composition patterned by these methods may volatilize the dispersion medium contained therein and then baked by heating to form a conductive pattern, but the ultrafine metal particle-containing composition mainly composed of silver It is possible to develop conductivity by acting on metal ultrafine particles mainly composed of silver described in JP2008-4375A, JP2008-235224A, and JP2008-167825A. And a conductive pattern containing a metallic substance (hereinafter referred to as a conductive developer) in any one of a support, a porous layer, an undercoat layer, or a plurality of layers, and bonding metal ultrafine particles to each other by a chemical action. More preferably. As the layer to be contained, a porous layer is particularly preferable. Particularly preferred as the conductive developer is, for example, a compound having a halogen in the molecule by an ionic bond such as sodium chloride or potassium chloride, an alkali metal salt, alkaline earth metal salt or ammonium salt of thiosulfuric acid. Moreover, it is also one of the preferable aspects to use multiple types of these substances together.

  Next, the filling of the resin in the present invention will be described. In the production method of the present invention, after forming the conductive pattern, the entire surface or part of the surface having the porous layer of the substrate for forming a conductive pattern is filled with resin. The whole surface of the base material refers to a region where the entire surface of the conductive pattern forming part and the whole surface of the non-formed part are combined, and part of the base material means the whole surface of the conductive pattern forming part and the partial surface of the non-formed part Refers to the combined area. In order to protect the conductive pattern, it is necessary to make the entire surface of the pattern forming portion the subject of resin filling, but it is not always necessary to make the entire surface of the non-formed portion the subject of resin filling. . For example, when it is necessary to additionally form a conductive pattern on an unformed part, filling the resin into the part may hinder subsequent operations.

  In the present invention, filling the resin means that the resin is infiltrated from the outermost surface toward the support body with respect to the entire surface or a part of the surface having the porous layer, and voids existing in the porous layer are made into the resin. Means satisfying. This void refers to the void of the porous layer remaining in the conductive pattern forming portion, and refers to the void of the porous layer in the portion where the conductive pattern is not formed.

  In order to fill the voids with the resin, the resin is applied in an amount greater than the void volume of the porous layer. When the amount of the resin supplied is less than the void volume of the porous layer, the metal structure of the pattern cannot be satisfactorily covered with the resin, and sufficient protection of the pattern cannot be expected. When the amount of resin supplied is equal to or greater than the void volume of the porous layer, the pattern is buried in the resin, so that the pattern can be sufficiently protected.

The void volume of the porous layer as used in the present invention refers to the accumulation from the pore radius of 3 nm to 400 nm in the porous layer portion measured and processed using a mercury porosimeter (measuring instrument name: Autopore II 9220, manufacturer, micromeritics instrument corporation). By multiplying the pore volume (mL / g) by the coating solid content (g / m ² ) of the porous layer, it can be obtained as a numerical value per unit area (m ² ).

  In the present invention, it is preferable to use a liquid resin as the resin to be filled in the porous layer in order to facilitate filling into the porous layer located inside and below the conductive pattern. Here, the liquid resin referred to in the present invention means a resin that is liquid by itself, a solution in which a water-soluble resin is dissolved in water, or a solution in which an oil-soluble resin is dissolved in various organic solvents.

  Examples of the resin that is liquid by itself can include known curable resins widely known as thermosetting trees, photocurable resins, electron beam curable resins, moisture curable resins, and the like. In addition to such a curable resin, a thermoplastic resin heated to a molten state can be similarly exemplified.

  Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, and silicone resin. One type of thermosetting resin may be used, or two or more types may be mixed and used.

  The photocurable resin may be an oligomer, and examples thereof include urethane acrylate, epoxy acrylate, ester acrylate, acrylate, epoxy, and vinyl ether resins. The oligomer of the photocurable resin to be used may be one kind or a mixture of two or more kinds.

  The electron beam curable resin may be an oligomer, and examples thereof include unsaturated polyester, unsaturated acryl, epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, and polyene / polythiol. One type of electron beam curable resin may be used, or two or more types may be used in combination.

  Examples of moisture curable resins include moisture curable epoxy resins and moisture curable polyurethane resins. One type of moisture curable resin may be used, or two or more types may be mixed and used.

  A wide variety of known resins can be used as the thermoplastic resin. Specific examples include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, acrylonitrile butadiene copolymer resin, polybutylene terephthalate, polyvinylidene chloride, polycarbonate, polyamide, polyacetal, polyimide, methacrylic resin, and fluorine resin. One type of thermoplastic resin may be used, or two or more types may be mixed and used. The melting point of the thermoplastic resin to be used is not particularly limited. However, when a film made of a resin is used as the support for the substrate for forming a conductive pattern, the melting point of the support can be prevented from being below the melting point of the support. Specifically, specifically, 150 ° C. or less is preferable.

  Examples of water-soluble resins include water-soluble celluloses such as methyl cellulose, ethyl cellulose, and propyl cellulose; gelatins such as glue, acid-treated gelatin, alkali-treated gelatin, and phthalated gelatin; polyvinyl alcohol, silanol-modified polyvinyl alcohol, and diacetone acrylamide-modified polyvinyl. Polyvinyl alcohols such as alcohol, polysaccharides such as carrageenan and gum arabic can be widely used. One type of water-soluble resin may be used, or two or more types may be mixed and used. The molecular weight of the water-soluble resin is preferably 10,000 or more, more preferably 50,000 or more.

  The oil-soluble resin is not particularly limited as long as it dissolves in the organic solvent to be used and has a film-forming property. For example, petroleum hydrocarbon resin, vinyl resin, alkyd resin, methacrylic resin, methyl methacrylate resin, epoxy resin, polyurethane resin, acrylonitrile resin, fluororesin, silicone resin, formalin resin, polyester resin, polyethylene resin, ketone resin, polyamide resin And synthetic resins such as maleic acid resin, chromanic acid resin and alicyclic resin, rosin ester and natural resin ester, semi-synthetic resin such as ethyl cellulose, and natural resin such as rosin resin and carboxylic acid resin. One type of oil-soluble resin may be used, or two or more types may be mixed and used.

  The organic solvent is not particularly limited as long as it dissolves the oil-soluble resin to be used. For example, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents and the like can be mentioned. More specifically, hydrocarbons such as toluene, xylene, solvent naphtha, normal hexane, cyclohexane, normal heptane, alcohols such as ethanol, isopropanol, 2-ethylhexyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, di Ketones such as acetone alcohol, esters such as ethyl acetate, butyl acetate, cellosolve acetate, methyl lactate, butyl lactate, ethyl lactate, methyl cellosolve, cellosolve, butyl cellosolve, carbitol, butyl carbitol, diethylene glycol monomethyl ether, triethylene glycol Monomethyl ether, diglyme, triglyme, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol , Glycol ethers such as dipropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, carbitol acetate, glycol esters such as dipropylene glycol monomethyl ether acetate, ethylene glycol, diethylene glycol, Glycols such as triethylene glycol and propylene glycol, others, ethyl 3-ethoxypropionate, dibasic acid ester, dimethyl carbonate, N, N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dioxolane, γ -Butyrolactone, dimethyl sulfoxide, dimethylformamide and the like. One type of organic solvent may be used, or two or more types may be mixed and used.

  As described above, various types of resins can be used as the resin to be filled in the porous layer. However, in order to effectively protect the conductive pattern from components in the atmosphere, a resin having a high gas barrier property is used. It is preferable. Specifically, polyamide resin, vinylidene chloride resin, epoxy resin, polyvinyl alcohol resin and the like are preferable.

  Additives other than resin and solvent can be added and used. For example, when a water-soluble resin is used as a solution in water, it can be used as a liquid resin by adding an organic solvent, if necessary, a leveling agent, a surfactant or the like.

  Liquid resin is applied by slide curtain method, slide bead method, slot die method, direct gravure roll method, reverse gravure roll method, spray method, air knife method, blade coating method, rod bar coating method, spin coating method, ink jet method, etc. Porous substrates of conductive pattern forming substrates using various known coating or printing methods such as screen printing, inkjet printing, dispenser printing, offset printing, reverse offset printing, gravure printing, flexographic printing, etc. The resin can be filled by applying to the entire surface or a part of the surface having the quality layer. Moreover, when the base material for conductive pattern formation is three-dimensional, it can be filled with resin by using the same method as the formation of the porous layer.

  Examples of the application of the conductive material obtained by the present invention include physical electrical devices such as non-contact IC cards, RFID inlays using various radio bands such as HF band and UHF band, RFID tags, RFID labels, connectors and terminals. Non-contact media that exchanges information using electromagnetic waves such as radio waves without using contacts, electromagnetic wave shields, and other applications where the conductive pattern is easily exposed to the atmospheric environment can be exemplified, but are not limited thereto. .

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

<Creation of substrate for forming conductive pattern>
Nitric acid (2.5 parts) and alumina hydrate (average primary particle size 15 nm) were added to water, and an inorganic fine particle dispersion having a solid content concentration of 30% by mass was obtained using a sawtooth blade type disperser. . The average secondary particle diameter of the alumina hydrate dispersed in the inorganic fine particle dispersion was 160 nm. Using this inorganic fine particle dispersion, a porous layer forming coating solution having the following composition was prepared.

<Porous layer forming coating solution>
Inorganic fine particle dispersion (as alumina hydrate solid content) 100g
Polyvinyl alcohol 12g
(Saponification degree 88%, average polymerization degree 3,500, molecular weight about 150,000)
Boric acid 0.5g
Nonionic surfactant 0.3g
(Polyoxyethylene alkyl ether)
It adjusted with water so that solid content concentration might be 16 mass%.

A 100 μm thick polyethylene terephthalate film (manufactured by Teijin DuPont Films Co., Ltd.) subjected to easy adhesion treatment was used as the support, and the porous layer forming coating solution was used as a solid content of alumina hydrate on the support at 30 g / Coating was performed using a slide bead method so as to be m ^2, and drying was performed with a dryer to form a porous layer. The thickness of the porous layer formed on the support is about 40 μm.

On the said porous layer, the electroconductive expression agent coating liquid of the following composition was apply | coated using the application | coating system using a diagonal gravure roll, and it dried with the drier, and obtained the base material for electroconductive pattern formation. The oblique gravure roll used here is a gravure roll having a diameter of 60 mm, an oblique line angle of 45 degrees, a number of lines of 90 lines / inch, and a groove depth of 110 μm, and was used in reverse rotation. The moisture application amount of the conductive expression agent coating solution was set to 20 g / m ² by adjusting the rotation speed of the oblique gravure roll. The obtained substrate for forming a conductive pattern was processed into a 210 mm × 297 mm sheet. The void volume measured using a mercury porosimeter was 23.0 ml / m ² .

<Conducting agent coating liquid>
Sodium chloride 1.0g
99.0g of water

<Preparation of metal ultrafine particle dispersion>
To a 2 L stainless beaker, 54.4 g of roasted dextrin (manufactured by Nissho Chemical Co., Ltd., dextrin No. 1-A) and 860 g of pure water were added and stirred for dissolution for about 30 minutes. Thereafter, 131.8 g of silver nitrate was added and dissolved by stirring for about 30 minutes. This solution is cooled to about 5 ° C. in an ice bath, a 10 ° C. solution in which 60.9 g of potassium hydroxide is dissolved in 83.9 g of pure water is added, and the reduction reaction is 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, 200 mg 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 became 45% by mass to obtain 156 g of ultrafine silver particle dispersion. The silver ultrafine particles contained had an average particle diameter of 20 nm and a yield of 84%.

<Preparation of a composition containing ultrafine metal particles>
100 g of the silver ultrafine particle dispersion was taken, and a surfactant, pure water, ethylene glycol was added as a wetting agent, and a composition containing ultrafine metal particles having a silver concentration of 15% by mass, a surface tension of 32 mN / m and a viscosity of 3.5 mPa · s Obtained.

<Preparation of metal ultrafine particle containing part>
Using a commercially available piezo-type inkjet printer containing a composition containing ultrafine metal particles on a conductive pattern forming substrate, a rectangle having a short side of 1 cm and a long side of 12 cm is drawn on the conductive pattern forming substrate. A straight line-like ultrafine metal particle-containing part was formed. The longitudinal direction of the straight line to be drawn was the same as the scanning direction of the inkjet head. The amount of supported silver measured using a fluorescent X-ray analyzer (ZSX Primus, manufactured by Rigaku Corporation) was 3.5 g / m ² . The void volume of the metal ultrafine particle-containing part measured using a mercury porosimeter was 22.9 ml / m ² . Thereafter, the ultrafine metal particle-containing portion was cut out along with a region having a short side of 3 cm and a long side of 12 cm including the periphery.

<Preparation of liquid resin 1>
20 g of AQ nylon P-70 (water-soluble polyamide resin) manufactured by Toray Industries, Inc. was dissolved in 80 g of water to obtain liquid resin 1.

<Preparation of conductive pattern 1>
Using a wire bar, the liquid resin 1 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm each of both ends in the long side direction, of the cut out ultrafine metal particle-containing portion. A conductive pattern 1 filled with / m ² of resin was obtained.

<Preparation of liquid resin 2>
20 g of Saran Resin F310 (vinylidene chloride resin) manufactured by Asahi Kasei Chemicals Co., Ltd. was dissolved in 80 g of methyl ethyl ketone to obtain liquid resin 2.

<Preparation of conductive pattern 2>
Using a wire bar, the liquid resin 2 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm of both ends in the long-side direction in the cut-out part of the ultrafine metal particles. A conductive pattern 2 filled with / m ² of resin was obtained.

<Preparation of liquid resin 3>
5 g of IRGACURE 500 (1-hydroxy-cyclohexyl-phenyl-ketone / benzophenone) manufactured by BASF Japan Ltd. as a photopolymerization initiator for 95 g of beam set AQ-9 (epoxy acrylate oligomer) manufactured by Arakawa Chemical Industries, Ltd. In addition, a liquid resin 3 was obtained.

<Preparation of conductive pattern 3>
Using a wire bar, the liquid resin 3 is applied to a region of 3 cm short side and 10 cm long side leaving 1 cm each of both ends in the long side direction of the cut out part containing ultrafine metal particles, cured with ultraviolet rays, and solid Conductive pattern 3 filled with 28 mL / m ² of resin per minute was obtained.

<Preparation of liquid resin 4>
8 g of polyvinyl alcohol was dissolved in 92 g of water to obtain a liquid resin 4.

<Preparation of conductive pattern 4>
Using a wire bar, the liquid resin 4 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm each of both ends in the long side direction, of the cut out ultrafine metal particle-containing portion, and the solid content is 28 mL. Conductive pattern 4 filled with / m ² of resin was obtained.

<Preparation of liquid resin 5>
20 g of gelatin was dissolved in 80 g of water to obtain a liquid resin 5.

<Preparation of conductive pattern 5>
Using a wire bar, the liquid resin 5 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm of both ends in the long side direction, of the cut out part containing the ultrafine metal particles. Conductive pattern 5 filled with / m ² resin was obtained.

<Preparation of conductive pattern 6>
A conductive pattern 6 was obtained without applying a liquid resin to the cut-out metal ultrafine particle-containing part.

<Preparation of conductive pattern 7>
Using a wire bar, the liquid resin 4 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm each of both ends in the long side direction, and 38 mL in solid content. A conductive pattern 7 filled with a resin of / m ² was obtained.

<Preparation of conductive pattern 8>
Using a wire bar, the liquid resin 4 is applied and dried to a region having a short side of 3 cm and a long side of 10 cm, leaving 1 cm each of both ends in the long side direction in the cut out part of the ultrafine metal particles, and the solid content is 18 mL. A conductive pattern 8 sealed with a resin of / m ² was obtained.

<Preparation of conductive pattern 9>
Using a wire bar, the liquid resin 4 is applied and dried to the area of 3 cm short side and 10 cm long side leaving 1 cm of both ends in the long side direction of the above-mentioned ultrafine metal particle-containing part, and the solid content is 8 mL. A conductive pattern 9 sealed with a resin of / m ² was obtained.

<Evaluation of storage stability>
About the said conductive patterns 1-9, the resistance value between the liquid resin non-application part of a metal ultrafine particle containing part both ends was measured using the tester. Then, the liquid resin application part of each electroconductive pattern was exposed to 10 ppm ozone gas. After exposure for a certain time, the resistance value was measured by the same method, and the change was evaluated. Table 1 shows the measurement results of resistance values after exposure to ozone gas for 24 hours, 48 hours for exposure, and 72 hours for exposure, assuming that the resistance value before exposure is 100.

  As is apparent from the results in Table 1, it can be seen that the present invention can provide a conductive pattern with good storage stability.

Claims (2)

  A conductive pattern is formed by printing or applying a composition containing metal ultrafine particles on a porous layer of a conductive pattern forming substrate having a porous layer composed of fine particles and a resin binder on a support, and thereafter A method for producing a conductive material, characterized in that a resin is filled in the entire surface or a part of a surface having a porous layer of a substrate for forming a conductive pattern.   The electroconductive material obtained by the manufacturing method of Claim 1.