KR20170021223A - Method for producing core-shell type metal fine particles, core-shell type metal fine particles, and method for producing substrate and electrically conductive ink - Google Patents

Abstract

The present invention relates to a method for producing core-shell type metal fine particles formed by a shell component containing copper and a core component containing copper, comprising the steps of: preparing copper particles and silver particles; A step of adsorbing a plurality of the silver particles on the surface of the copper particles through simultaneous decomposition in an organic solvent and a step of heating the copper particles on which the silver particles have been adsorbed, And fusing the silver particles with each other to form a shell component containing silver on the surface of the copper particles.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing core-shell type metal fine particles, a core-shell type metal fine particle, a conductive ink, and a method for manufacturing a substrate,

The present invention relates to a method for producing core-shell type metal fine particles, a core-shell type metal fine particle, a conductive ink and a method for producing a substrate.

A method is known in which a conductive ink containing fine metal particles is coated on a substrate and fired to form a wiring. As the metal fine particles to be used for such conductive ink, for example, shell fine metal particles can be considered as the core of the copper.

The core is, for example, the following as a prior art relating to shell-type metal fine particles.

Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2007-224420) discloses a method for forming a thin film layer containing copper as a core and surrounding the core with a noble metal to prevent oxidation of the copper, thereby increasing the copper content and ensuring economic profitability. And a conductive ink containing the metal nanoparticles. In order to solve this problem, the metal nanoparticles described in Patent Document 1 employ a configuration including a copper core and a thin metal layer of the metal surrounding the copper core. This document discloses that such metal nanoparticles are formed by the steps of forming copper nanoparticles from a copper precursor using a reducing agent in a solvent containing a primary amine and forming metal nanoparticles on the surfaces of the copper nanoparticles, And forming a thin film layer of the metal having the high reducing potential from the precursor.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-185135) discloses a core-shell type nano metal having a core component containing a metal having a high ionization tendency and a shell containing a metal having a lower ionization tendency than that covering each core component. The problem is that the particles can be obtained. In order to solve the related problem, the core-shell type metal nanoparticle production method described in Patent Document 2 includes a core component containing a metal A having a higher ionization tendency and a core component containing a metal component B having a lower ionization tendency (1) for reducing metal A ions to form fine particles of metal A in deoxygenated high boiling point (boiling point), and a step A solution containing a metal B ion in a state where the metal B ion is maintained at a temperature higher than 80% for reducing the metal B in 1 minute, (2) in which the catalyst is added.

Japanese Patent Application Laid-Open No. 2007-224420 (Patent Document 002) Japanese Patent Application Laid-Open No. 2010-185135

However, as described in Patent Documents 1 and 2 and the like, conventionally copper cored metal fine particles are not sufficiently satisfactory in conductivity.

The present invention provides a core-shell type metal microparticle excellent in conductivity as judged by the above circumstances of the present invention.

The inventors of the present invention have intensively studied to provide core-shell type metal fine particles having excellent conductivity. As a result, the conventional core-shell type metal fine particles having low conductivity have found that a shell component containing silver is not well coated with a core component containing copper, It is found that the structure is the same as that adsorbed on copper. With such a structure, since copper oxidation does not occur, copper oxidation gradually appears. As a result, the conductivity of the core-shell type is lowered. Here, the inventors of the present invention have found that, in the conventional copper cores, shell-type metal microparticles form silver on the surfaces of copper particles from a solution reduction method in which silver ions are reduced on the surface of copper particles to precipitate silver, Were observed to have produced aggregates. In order to improve the coating state of silver on copper particles, the inventors of the present invention have extensively studied the production method of shell-type metal fine particles. As a result, the silver particles and the plurality of silver particles are adsorbed to each other on the solid, and then the silver particles adsorbed on the surface of the copper particles are fused by heating to fuse the plurality of silver particles to each other, Shell-type metal microparticles excellent in conductivity and excellent in the coating state of silver can be obtained. Thus, the present invention has been completed.

The present invention is based on this knowledge.

That is, according to the present invention, A method of producing core-shell metal fine particles formed from a shell component containing a core component containing copper and silver, A step of preparing copper particles and silver particles, A step of adsorbing a plurality of the silver particles on a surface of the copper particles from the time of simultaneously decomposing the copper particles and the silver particles into an organic solvent; A plurality of the silver particles adsorbed on the surface of the copper particles are fused to each other to form a shell component containing the silver particles on the surface of the copper particles from heating the copper particles adsorbed by the silver particles fair, Wherein the core-shell-type metal microparticles are dispersed in water.

Further, according to the present invention, There is provided core-shell-type metal microparticles obtained by the above-mentioned process for producing core-shell-type metal microparticles.

Further, according to the present invention, There is provided a conductive ink comprising the core-shell-type metal fine particles, a binder resin, and a solvent containing at least one of water and an organic solvent.

Further, according to the present invention, A method of manufacturing a substrate having a predetermined conductive pattern, A coating step of applying the conductive ink to a predetermined area of the substrate, and a step of heating the area to include the core-shell metal fine particles of the conductive ink with each other.

According to the present invention, it is possible to provide core-shell type metal fine particles excellent in conductivity.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a SEM photograph of shell-type fine metal particles obtained in Example 1. FIG. 2 is a SEM photograph of shell-type fine metal particles obtained in Comparative Example 2. Fig. [Fig. 3] The copper core obtained in Comparative Example 3 is a SEM photograph showing shell-type metal fine particles.

Hereinafter, embodiments of the present invention will be described.

≪ Process for producing core-shell type metal fine particles & Is formed from a shell component containing silver and a core component containing copper according to the present embodiment. The core-shell type metal fine particle manufacturing method according to the present embodiment includes the following three steps. (1) Process of preparing copper particles and silver particles (2) a step of adsorbing a plurality of the silver particles on the surface of the copper particles, from the step of simultaneously decomposing the copper particles and the silver particles into an organic solvent (3) Since the copper particles on which the silver particles are adsorbed are heated, And fusing a plurality of the silver particles adsorbed on the surface of the copper particles to each other to form a shell component containing silver on the surface of the copper particles.

According to the method for producing core-shell metal fine particles according to this embodiment, copper particles and a plurality of silver particles are adsorbed on a solid to each other, and then heated to adsorb on the surface of the copper particles to melt the silver particles, The silver particles fuse each other. From this, it is possible to stably produce the core-shell type metal fine particles having improved silver coverage and excellent conductivity. The reason why the core-shell type metal fine particles having improved silver coverage and excellent conductivity can be obtained from such a production method is not necessarily clear, but the following reasons can be considered. First, the surface layer of the decomposed silver particles is adsorbed to such an extent as to cover at least the entire surface of the copper particles as possible, so that a layer appearing from the silver particles is formed. Further, from the fact that it is heated, it can be considered that fusion occurs between the particles when the silver particles cover the entire surface of the copper particles, and a silver shell component having excellent covering property to copper is formed. From this, it is possible to obtain core-shell-type metal microparticles having improved coverage of silver. It can be considered that such core-shell type metal fine particles can effectively inhibit copper oxidation from a shell component containing silver and thus can be excellent in conductivity.

Hereinafter, each process will be described in detail.

[Process for preparing copper particles and silver particles] First, copper particles and silver particles are prepared as raw materials for the core-shell type metal fine particles according to the present embodiment.

(Copper particles) The copper particles as the raw material are not particularly limited, and conventionally known copper particles can be used. As commercially available copper particles, for example, a spherical copper powder (product name: CUE12PE) manufactured by High Purity Chemical Laboratories can be used. Alternatively, it may be manufactured by copper particles, a reduction method, a disproportionation process, or the like. In the present embodiment, the particle shape of the copper particles may be spherical or plate-like.

The average particle diameter of the copper particles is preferably 100 nm or more and 20 占 퐉 or less, more preferably 100 nm or more and 10 占 퐉 or less, and particularly preferably 100 nm or more and 1 占 퐉 or less. If the average particle size of the copper particles is not less than the above lower limit value, the flow characteristics of the conductive ink obtained are further improved. If the average particle size of the copper particles is not more than the lower limit value described above, a finer wiring pattern can be formed, and the resistance value of the obtained circuit is further reduced. Here, in the present embodiment, the term "average particle diameter" means a particle diameter of 50% of the quantity surveying value in the particle diameter distribution obtained by measurement of the forward tangential line (Feret diameter) do. The term "particle diameter distribution" means a value obtained by measuring the particle diameter of about 300 particles randomly on an SEM.

The copper particles according to the present embodiment are usually used in the form of a suspension by decomposition into an organic solvent. The organic solvent to be used is not particularly limited, but a hydrophobic solvent such as hexane, benzene, toluene, diethyl ether, chloroform, ethyl acetate, methylene chloride or the like is preferable. From this, it is possible to suppress coagulation of copper particles in the production of core-shell type metal fine particles. The organic solvent to be used may be used alone, or two or more kinds may be used in combination.

The concentration of the copper particles in the suspension containing the copper particles is, for example, 1 g / L or more and 500 g / L or less.

In addition, from the viewpoint of suppressing coagulation of copper particles, it is preferable that the suspension containing copper particles is blended with the release agent. From the viewpoint of improving the covering property of the silver particles covering the copper particles, it is preferable to use an inorganic acid such as butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, , Naphthenic acid, pentenoic acid, hexanoic acid, heptenoic acid, undecylenic acid, oleic acid, linoleic acid and linolenic acid. These may be used alone, or two or more of them may be used in combination.

 The amount of the dispersant to be incorporated in the suspension is not particularly limited as long as it is an amount capable of inhibiting agglomeration of copper particles. For example, it is 1 part by weight or more and 100 parts by weight or less based on 100 parts by weight of copper particles.

In addition, various reducing agents may be added to the suspension containing the copper particles from the viewpoint of once again removing the oxides present on the surface of the copper particles. The reducing agent may be a solvent having a reducing ability, or a reducing agent other than a solvent may be blended.

Examples of the reducing agent include aliphatic monoalcohols such as methanol, ethanol, isopropanol, 2-butanol and 2-hexanol; Aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, 1,3-propanediol, glycerin and 1,2-butanediol; Aromatic monoalcohols such as benzyl alcohol, 1-phenylethanol, diphenylcarbitol and benzoin; Aromatic polyhydric alcohols such as hydrobenzoin; Sugars such as glucose, maltose and fructose; High molecular weight alcohols such as polyvinyl alcohol and ethylene vinyl alcohol; Amine compounds such as dimethylamine ethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine; hydrogen compounds such as sodium borohydroride, hydrogen sulphide, and hydrogen gas; Ferric oxalate, ferric oxide, tin acetate, tin chloride, tin, and the like, and oxides such as carbon monoxide, sulfurous acid and the like; ferrous sulphate, ferric chloride, ferrous fumarate, ferrous oxalate, ferrous oxalate, Low valence metal salts such as tin diphosphate, tin oxalate, tin oxide, and tin sulfate; Organic compounds such as formaldehyde, hydroxynon, pyrogallol, tannin, tannic acid, and 2-hydroxybenzoic acid. The reducing agent to be used may be used alone, or two or more kinds of reducing agents may be used in combination.

The amount of the reducing agent to be incorporated in the suspension is not particularly limited as long as it is an amount capable of sufficiently removing oxides present on the surface of the copper particles, and is, for example, 1 part by weight or more and 200 parts by weight or less based on 100 parts by weight of copper particles.

(Silver particles)

The raw silver phosphor particles are not particularly limited and it is possible to use silver nanoparticles generally used. As commercially available silver particles, for example, nanoparticles (product name: NM-0037-HP) manufactured by IoLiTec can be used. Alternatively, the silver particles can be produced by a reduction method, a thermal decomposition method or the like. In the present embodiment, the shape of the silver particles may be spherical or irregular.

The average particle diameter of the silver particles is preferably from 1 nm to 200 nm, and more preferably from 2 nm to 50 nm. When the average particle diameter of the silver particles is not less than the above lower limit value, the silver coverage of the obtained core-shell type metal fine particles is further improved. When the average particle diameter of the silver particles is not more than the upper limit value, it is possible to form a finer wiring pattern, and the resistance value of the obtained circuit can be further reduced.

The silver particles according to the present embodiment are usually used in the form of a suspension by decomposition into an organic solvent. As the organic solvent to be used, any of a hydrophobic solvent and a hydrophilic solvent may be used. But are not limited to, hydrophobic solvents such as mineral oil, fatty acids, alcohols and hydrocarbons; Alcohols such as ethylene glycol and propylene glycol, polyhydric alcohols such as glycerin, sugar alcohols, lower alcohols such as ethanol, methanol, propanol and butanol, glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether , Aliphatic amines such as methylamine and triethylamine, alkanolamines such as ethanolamine and triethanolamine, amides such as n-methylacetamide and n-methylformamide, and the like; . Through this, it is possible to suppress generation of silver agglomerates at the time of manufacturing core-shell type metal fine particles. The organic solvent to be used may be used alone, or two or more kinds may be used in combination. The concentration of the silver particles in the suspension containing the silver particles is, for example, 1 g / L or more and 1000 g / L or less.

In addition, it is preferable that the suspension containing silver particles includes decomposition to inhibit agglomeration of silver particles. From the viewpoint of raising the coverage of the silver particles covering the copper particles, it is preferable to use a metal salt such as pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, hexadecylamine, And an alkylamine-based decomposing agent such as octadecylamine. These may be used alone, or two or more of them may be used in combination.

The amount of the disintegrating agent to be incorporated in the suspension is not particularly limited as long as it is an amount capable of inhibiting agglomeration of the silver particles. For example, it is 1 part by weight or more and 100 parts by weight or less with respect to 100 parts by weight of silver particles.

Here, by using the above-described carboxylic acid type decomposition release as the decomposition of the copper particles and using the alkylamine-based decomposition release as the decomposition of the silver particles, the coating property of the silver particles covering the copper particles can be improved more effectively It is possible.

[Step of adsorbing a plurality of silver particles on the surface of copper particles] Next, copper particles and silver particles are simultaneously decomposed in an organic solvent, and a plurality of silver particles are adsorbed on the surface of the copper particles.

The method of simultaneously decomposing the copper particles and the silver particles in the organic solvent is not particularly limited. For example, a suspension obtained by dissolving particles in an organic solvent is added to a suspension obtained by dissolving copper particles in an organic solvent, A method in which a suspension obtained by dissolving copper particles in an organic solvent is added to a suspension obtained by dissolving particles in an organic solvent and a method in which the resulting mixture is homogeneously compounded; A method in which silver particles are added to the mixture and the resulting mixture is uniformly blended, a method in which copper particles are added to a suspension obtained by dissolving the particles in an organic solvent, and a method in which the resulting mixture is uniformly blended. Among them, a suspension obtained by dissolving particles in an organic solvent is added to a suspension obtained by dissolving copper particles in an organic solvent from the viewpoint of more effectively inhibiting the aggregation of silver particles and copper particles, and the obtained mixture solution is homogeneously A method of blending is preferable.

Here, in order to sufficiently adsorb silver particles on the surface of the copper particles, it is preferable to blend the above-mentioned compounding liquid at 10 to 40 DEG C for 5 to 30 minutes, for example.

The organic solvent to be used when the copper particles and the silver particles are decomposed at the same time may be any of a hydrophobic solvent and a hydrophilic solvent. But are not limited to, hydrophobic solvents such as mineral oil, fatty acid, alcohol, and hydrocarbon; Alcohols such as ethylene glycol and propylene glycol, polyhydric alcohols such as glycerin, sugar alcohols, lower alcohols such as ethanol, methanol, propanol and butanol, glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether , Aliphatic amines such as methylamine and triethylamine, alkanolamines such as ethanolamine and triethanolamine, amides such as n-methylacetamide and n-methylformamide, and the like; . This makes it possible to inhibit the generation of agglomerates of copper or silver during the production of the core-shell type metal microparticles. The organic solvent to be used may be used alone, or two or more kinds may be used in combination.

 The amount of silver particles decomposed in the organic solvent is preferably 1 part by weight or more and 80 parts by weight or less, more preferably 2 parts by weight or more and 40 parts by weight or less, particularly preferably 5 parts by weight or less, Parts by weight or more and 25 parts by weight or less. When the amount of the silver particles decomposed in the organic solvent is not less than the lower limit value, the covering property of the silver particles to the copper particles is further improved. When the amount of the silver particles decomposed in the organic solvent is not more than the upper limit value, generation of agglomerates of silver particles can be suppressed more effectively.

[Process of forming a shell component containing silver on the surface of copper particles] Subsequently, since the copper particles adsorbed by the silver particles are heated, a plurality of silver particles adsorbed on the surface of the copper particles are fused to each other to form a shell component containing silver on the surface of the copper particles.

The heating temperature for heating the copper particles adsorbed by the silver particles is not particularly limited, but is preferably 60 ° C or more and 150 ° C or less. It is known that silver nanoparticles have a lower melting point due to the nanosize effect. Therefore, when silver nanoparticles are used as the silver particles, the silver nanoparticles can be fused with each other even at such a relatively low temperature to form a shell component containing silver on the surface of the copper particles.

The heating time for heating the copper particles adsorbed by the silver particles is not particularly limited, but is, for example, 10 minutes or longer and 2 hours or shorter.

From the above steps, it is possible to obtain core-shell type metal fine particles excellent in conductivity. Further, the core-shell type metal fine particles may be separated from the obtained suspension by a known separation method such as centrifugation as necessary.

≪ Core shell type metal fine particles & The core-shell type metal fine particles obtained by the production method of the present embodiment can be suitably used as conductive particles for use in, for example, conductive ink. Since the core-shell type metal fine particles obtained by the production method of this embodiment have better silver coverage and excellent conductivity, the circuit obtained using the conductive ink containing such core-shell type metal fine particles has excellent conductivity .

The average particle diameter of the core-shell type metal fine particles is preferably 100 nm or more and 20 占 퐉 or less, more preferably 100 nm or more and 10 占 퐉 or less, and particularly preferably 100 nm or more and 1 占 퐉 or less. When the average particle diameter of the core-shell type metal fine particles is not less than the upper limit value, the flow characteristics of the conductive ink obtained are further improved. When the average particle diameter of the core-shell type metal fine particles is not more than the upper limit value, a finer wiring pattern can be formed, and the resistance value of the resulting circuit can be further reduced.

<Conductive ink> The conductive ink according to the present embodiment contains the core-shell metal fine particles, the binder resin, and a solvent containing at least one of water and an organic solvent.

The conductive ink is, for example, a liquid obtained by decomposing the core-shell-type metal fine particles and the binder resin into a solvent containing at least one of water and an organic solvent.

It is possible to apply the conductive ink to a substrate by, for example, an ink jet method or a screen printing method, dry it, and then heat it to form a conductive member such as a metal particle containing wiring or a thin film.

In the present embodiment, the conductive ink may be in the form of an emulsion or a suspension, and the solvent to be used is not particularly limited as long as it is a commonly used solvent.

The content of the core-shell-type metal microparticles in the conductive ink is, for example, 10 wt% or more and 94 wt% or less when the total amount of the conductive ink is 100 wt%.

(Binder resin) In the present embodiment, the conductive ink contains a binder resin. This binder resin functions as a binder for binding the core-shell-type metal fine particles to each other.

The form of the binder resin in the conductive ink may be dissolved in a solvent, or may be an emulsion or a cloudy solution. Examples of the binder resin include, but are not limited to, a polyester resin, a polyurethane resin, a polyamide resin, a polyvinyl chloride resin, a polyacrylamide resin, a polyether resin, an acrylic resin, a melamine resin, Vinyl acetate copolymer resin, fluorine resin, silicone resin, rosin, rosin ester, chlorinated polyolefin resin, modified chlorinated polyolefin resin, chlorinated polyurethane resin, chlorinated polyolefin resin, It is possible to add a resin, a cellulose resin, polyethylene glycol, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyvinyl butylal, polyvinyl pyrrolidone and the like. The binder resin to be used may be used alone or in combination of two or more.

The content of the binder resin in the conductive ink is, for example, 0.1 wt% or more and 10 wt% or less when the total amount of the conductive ink is 100 wt%.

(Organic solvent) The organic solvent used for the conductive ink may be either a hydrophobic solvent or a hydrophilic solvent.

As the hydrophobic solvent, an ink or the like may be generally used. For example, mineral oils, fatty acids, alcohols, hydrocarbons and the like can be mentioned.

Examples of the hydrophilic solvent include polyhydric alcohols such as ethylene glycol and propylene glycol, polyhydric alcohols such as glycerin, sugar alcohols, lower alcohols such as ethanol, methanol, propanol and butanol, ethylene glycol monomethyl ether, ethylene glycol Aliphatic amines such as methylamine and triethylamine; alkanolamines such as ethanolamine and triethanolamine; amides such as n-methylacetamide and n-methylformamide; and the like. have.

The organic solvent used for the conductive ink may be used alone or in combination of two or more.

(Silver particles) The conductive ink according to the present embodiment preferably further includes silver particles. As a result, the conductivity of the circuit obtained by using the conductive ink according to the present embodiment can be further improved. As the silver particles, it is possible to use the same silver particles as those used for producing the core-shell-type metal fine particles according to the present embodiment. The amount of the particles in the conductive ink is preferably 20 wt% or more and 50 wt% or less when the total amount of the conductive ink is 100 wt%.

(reducing agent) The conductive ink according to the present embodiment can be mixed with various reducing agents as needed. The reducing agent may be a solvent having a reducing ability, or a reducing agent other than a solvent may be added. As the reducing agent, there may be mentioned, for example, reducing agents such as those contained in suspensions containing full copper particles.

The amount of the reducing agent in the conductive ink is preferably 1 wt% or more and 10 wt% or less when the total amount of the conductive ink is 100 wt%.

(Minute release) To the conductive ink according to the present embodiment, various release agents may be added as needed. Examples of the decompositions include alkylamines such as pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, hexadecylamine and octadecylamine Such as, but not limited to, hydrochloric acid, sulfuric acid, sulfuric acid, nitric acid, sulfuric acid, nitric acid, sulfuric acid, , Oleic acid, linoleic acid, linolenic acid, and the like. These may be used singly or as a mixture of two or more of them.

The amount of disintegration in the conductive ink is preferably 1% by weight or more and 10% by weight or less when the total amount of the conductive ink is 100% by weight.

The conductive ink according to the present embodiment may contain various additives commonly used in conductive inks such as various defoamers, colorants, and surface conditioners, if necessary.

<Method of producing conductive ink> The conductive ink according to the present embodiment can be produced by a known method. For example, using a blender such as a triple roll mill, a bead mill, a ball mill, a planetary mixer, and a disperser, It is possible to prepare a conductive ink.

<Substrate> The substrate according to the present embodiment forms a conductive pattern by applying the conductive ink according to the present embodiment to a region of a substrate portion to heat the region and fusing the core shell-type metal microparticles in the conductive ink to each other And the like.

 The substrate is used, for example, in an electronic device such as an organic EL display, a solar cell, an electronic paper, or a flexible substrate

In the present embodiment, an inorganic substrate such as glass and various plastic substrates can be used for the substrate used for forming the substrate.

Examples of the plastic substrate include polyimide, polyamideimide, polyester, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polymethylacrylic acid, Polycarbonate, polyethylene naphthalate, and the like. Polyamideimide, or polyester from the viewpoint of heat resistance, mechanical properties, thermal properties, and the like.

As the shape of the substrate, a flat plate, a three-dimensional object, a film and the like are exemplified, and a film is suitably used. By using a resin film made from the above resin, it is possible to produce by the R2R (roll to roll) method, and it is possible to produce with high production efficiency.

Such a substrate is preferably washed with pure water or ultrasonic waves before applying the conductive ink.

&Lt; Substrate Manufacturing Method > A method of manufacturing a substrate according to the present embodiment is a method of manufacturing a substrate, comprising the steps of: applying a conductive ink to a predetermined region of a base material; heating the region to fuse the core-shell metal fine particles in the conductive ink to form a conductive pattern And a pattern forming step. This makes it possible to stably manufacture a substrate with a sufficiently reduced resistance value.

As a method of applying the conductive ink to a part of the base material, it is possible to use various known methods. For example, a screen printing method, an ink jet method, a dip coating method, a spray coating method, a spin coating method, a dispenser coating method, or the like can be used.

 In order to form a particularly fine wiring pattern, an ink jet method or a screen printing method is preferable.

Here, it is preferable that the amount of the conductive ink applied to the substrate is appropriately adjusted to a desired film thickness of a certain area. In the inkjet method, the conductive ink after drying is preferably in the range of 0.01 탆 or more and 10 탆 or less , And particularly preferably from 0.1 m to 10 m. As the screen printing method, the thickness of the conductive ink thin film after drying is preferably in the range of 0.1 占 퐉 to 100 占 퐉, and particularly preferably in the range of 1 占 퐉 to 50 占 퐉 .

In the pattern forming step, heating of the region to which the conductive ink is applied is preferably carried out at an arbitrary temperature higher than the melting point of the metal fine particles in consideration of thermal deformation and denaturation of the substrate. In addition, it is also possible to carry out a pattern forming step by using a heated substrate with a step of heating the substrate before the pattern forming step.

In the pattern forming process, various well-known heating methods can be used as the heating method for the region to which the conductive ink is applied. For example, external heating by a heating furnace, heating by microwave heating or current, induction heating, far-infrared heating, light heating and the like.

The pattern formation process can be performed under the atmosphere.

As described above, the embodiments of the present invention have been described. However, they are examples of the present invention, and various configurations other than those described above can be adopted. The present invention is not limited to the above-described embodiments, but variations, improvements and the like are included in the present invention within the scope of achieving the object of the present invention.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The raw material components used in each of the Examples and Comparative Examples are shown below. Single resolution Copper sulfate was prepared by reducing the aqueous solution of copper sulfate pentahydrate in two steps or using commercially available copper powder. The control of the average particle diameter of the three kinds of particles was performed by changing the PH and the temperature of the aqueous solution. Copper particle 1: Single isolated copper powder (average particle diameter: 0.5 탆) Copper particle 2: Single separated copper powder (average particle diameter: 0.2 탆) Copper particle 3: Single separated copper powder (average particle diameter: 1.0 탆) Copper Particle 4: Single Separated Copper Powder (average particle diameter: 5.0 탆, spherical powder (product name: CUE12PE) manufactured by High Purity Chemical Laboratories) Silver nanoparticle concentration: 500 g / L, solvent: n-octane, n-butanol, average particle size: 20 nm), silver nanoparticle solution (IoLitec silver nanoparticle nm) Reducing agent 1: Hydroxyhydrate (manufactured by Wako Pure Chemical Industries, Ltd.) Min 1: Oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) Min 2: n-hexylamine (manufactured by Kanto Chemical) Disintegration 3: n-Dodecylamine (manufactured by Wako Pure Chemical Industries, Ltd.) Binder resin: Polyester resin (Fres Resin S-680EA, manufactured by Takamatsu Suisen)

(Example 1) &Lt; Preparation of copper core shell particles > 1 g of copper particle 1 and 10 ml of toluene were added to a three-necked glass flask, and a mixed solution was obtained. Subsequently, the mixed solution was stirred at 400 rpm using a hot magnetic stirrer and a PTFE (tetrafluoroethylene) producing rotator in a three-necked glass flask under a nitrogen atmosphere. Through this, a suspension containing copper particles was obtained. Subsequently, 1.2 g of reducing agent 1 was added to the suspension containing the obtained copper particles and stirred to remove the oxide on the surface of copper particles 1. Subsequently, 0.22 g of the disintegrant 1 was added, and further stirred. While stirring the suspension, 0.5 g (silver particles: 0.25 g) of a suspension containing silver particles was added and stirred at room temperature (20 占 폚) for 10 minutes. Through this, a plurality of silver particles were adsorbed on the surface of the copper particles. Here, the suspension containing the silver particles contains 0.025 g of the decomposition 2 and 0.025 g of the decomposition 3 as the decomposition. Thereafter, the obtained suspension was heated and stirred in an oil bath at 120 占 폚 for 1 hour. Through this, a plurality of silver particles adsorbed on the surface of the copper particles were melted to fuse a plurality of silver particles to form a silver shell component on the surface of the copper particles. After stirring, 0.4 g of Dissolution 2 was added, and further stirred. Subsequently, 40 ml of methanol was added and centrifugation was carried out. The obtained precipitate was separated, again 40 ml of methanol was added, the precipitate was stirred, and centrifugation was carried out. Through this, the core obtained a precipitate of shell-type metal microparticles.

<SEM observation of copper core shell particles> The copper cores thus obtained were observed by a scanning electron microscope (FE-SEM S-4700, manufactured by Hitachi, Ltd.), and analyzed by an energy decomposition type X-ray analyzer (Horiba Corp. EMAX- 7000). As a result, it was confirmed that the copper core was a shell-type metal fine particle. In this copper core, the average particle diameter of the shell-type metal fine particles is 0.5 mu m. In addition, Fig. 1 shows an SEM photograph (photographing magnification: 100,000 times) of shell fine metal particles obtained in Example 1. From the SEM photograph of Fig. 1, it was confirmed that the coated state of silver was improved with respect to copper particles.

&Lt; Preparation of conductive ink & 0.3 g of the shell-type fine metal particles, 0.035 g of the binder resin and 0.037 g of the disintegrant 1 were added to 0.4 g of the above-mentioned suspension containing silver particles (silver particles: 0.2 g) Ink was obtained.

&Lt; Production of substrate & The conductive ink was coated on a glass plate and fired at 150 ° C for 1 hour in the atmosphere to prepare a copper having a thickness of 3.5 μm. This conductor measured the volume resistivity of the conductor and was 14 μΩ · Ecm. The measurement of the volume resistivity was carried out by the four-terminal method with Milli-ohm High tester 3540 (manufactured by Hioki Electric Co., Ltd.).

(Example 2) A copper fine metal particle, a conductive ink and a substrate were prepared in the same manner as in Example 1 except that Copper Particle 2 was used instead of Copper Particle 1.

(Example 3) Shell type fine metal particles, a conductive ink, and a substrate were prepared in the same manner as in Example 1 except that Copper Particle 3 was used instead of Copper Particle 1.

(Example 4) Shell type fine metal particles, a conductive ink, and a substrate were prepared in the same manner as in Example 1, except that copper particles 4 were used instead of copper particles 1.

(Comparative Example 1) A conductive ink and a substrate were prepared in the same manner as in Example 1, except that the copper core used in the production of the conductive ink was a copper-based metal fine particle.

(Comparative Example 2) In the same manner as in Example 1, except that the suspension was stirred in an oil bath at room temperature (20 占 폚) for 1 hour, instead of heating and stirring the suspension in an oil bath at 120 占 폚 for 1 hour, Fine particles, conductive ink, and a substrate were prepared.

(Comparative Example 3) In the same core as that of Example 1 except that 0.25 g of the silver complex of silver acetate was used as the suspension containing the silver particles when the shell-type metal microparticles were produced, the core had shell-type metal microparticles, conductive Ink, and substrate.

The results obtained are shown in Table 1. In addition, the copper cores obtained in Comparative Examples 2 and 3 in FIGS. 2 and 3 show SEM photographs (maximum observed magnification: 100,000 times) of the shell-type metal fine particles, respectively.

Core shell type
Of metal microparticles
Average particle diameter (占 퐉) Containing silver
Raw material for shell formation Heating temperature
(° C) Copper
Thin film thickness
(탆) Volume resistivity
(μΩ · cm) Example 1 0.5 Silver nanoparticles 120 3.5 14 Example 2 0.2 Silver nanoparticles 120 1.5 14 Example 3 1.0 Silver nanoparticles 120 4.5 20 Example 4 5.0 Silver nanoparticles 120 8.0 23 Comparative Example 1 0.5 - - 2.5 6000 Comparative Example 2 0.5 Silver nanoparticles Non-heating 2.7 521 Comparative Example 3 0.5 Amine complex of acetic acid silver 120 2.5 455

The substrates using the core-shell-type metal microparticles of Examples 1 to 4 produced by the manufacturing method according to the present embodiment have a small volume resistivity and excellent conductivity. On the other hand, the substrates using the core-shell-type metal microparticles of Comparative Examples 1 to 3 have high volume resistivity and low conductivity. 2 and 3, it was confirmed that core shell-type metal fine particles having low conductivity had a structure such that aggregates of silver were adsorbed on copper.

This application claims priority based on Japanese Patent Application No. 2014-130668, filed on June 25, 2014, which is incorporated herein by reference in its entirety.

Claims (10)

A method for producing core-shell metal fine particles formed from a shell component containing a core component containing copper and silver,
Preparing copper particles and silver particles;
A step of adsorbing a plurality of the silver particles on the surface of the copper particles, from the simultaneous decomposition of the copper particles and the silver particles in an organic solvent; And
A step of fusing a plurality of the silver particles adsorbed on the surface of the copper particles to form a shell component containing silver on the surface of the copper particles by heating the copper particles adsorbed by the silver particles, Wherein the core-shell-type metal fine particles have an average particle size of not more than 100 nm.
The method of producing core-shell type metal fine particles according to claim 1, wherein the copper particles adsorbed by the silver particles are heated to a heating temperature of 60 ° C to 150 ° C.
The method for producing core-shell type metal fine particles according to any one of claims 1 to 3, wherein the average particle diameter of the copper particles is 100 nm or more and 20 占 퐉 or less.
The method of producing a core-shell type metal fine particle according to any one of claims 1 to 3, wherein the silver particles have an average particle size of 1 nm to 200 nm.
The method for producing core-shell type metal microparticles according to any one of claims 1 to 4, wherein the amount of the silver dissolved in the organic solvent is 1 part by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the copper particles Way.
The method for producing core-shell type metal microparticles according to any one of claims 1 to 5, wherein the organic solvent is a hydrophobic solvent.
A core-shell-type metal fine particle produced by the method for producing core-shell metal fine particles according to any one of claims 1 to 6.
A conductive ink comprising core-shell metal fine particles of claim 7, and a solvent comprising at least one of a binder resin and water or an organic solvent.
9. The conductive ink of claim 8, further comprising silver particles.
A method of manufacturing a substrate having a constant conduction pattern,
9. A method for producing a conductive ink, comprising the steps of: applying an electroconductive ink according to claim 8 or 9 to a predetermined area of a substrate;
A pattern forming step of heating the region to fuse the core-shell-type metal fine particles in the conductive state to form a conductive pattern,
&Lt; / RTI &gt;

Images