Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/52—Electrically conductive inks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/20—Conductive material dispersed in non-conductive organic material
  • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
  • H05K3/12—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns

Definitions

• the present invention relates to a conductive paste and a method for forming a conductive pattern used for forming wiring and electrode patterns of a semiconductor integrated circuit, etc., and a conductive paste that contributes to thinning of a conductive pattern and the conductive paste.
• the present invention relates to a method for forming a conductive pattern used.
• Patent Document 1 Japanese Patent No. 5610112
• the conductive metal particles (A) and a solid at 50 ° C. are usually used.
• a conductive paste for bezel pattern printing by gravure offset printing comprising (C) and an organic solvent (D) having a boiling point of 170 to 300 ° C. at normal pressure which has no reactivity.
• the amount is 1.0 to 3.0% in terms of mass with respect to the sum of (A) to (D), and the sum of organic compound (B) and organic compound (C) in terms of mass of nonvolatile content
• Use amount R Both the mass ratio R / P when the amount is P of conductive metal particles (A), be from 0.07 to 0.15, a conductive paste is disclosed which is characterized. Further, in the conductive paste, 5 to 20% is disclosed as a suitable blanket swelling rate of the organic solvent.
• the non-volatile content of the organic compound (B) is conventionally higher than the total of the four components of the conductive metal particles (A) to the organic solvent (D).
• the mass ratio R / P of the non-volatile content of the organic compound (B) and the organic compound (C) and the conductive metal particles (A) is adjusted to be smaller than the conventional one. Therefore, even if printing is performed using a gravure plate having a complicated concave portion such as a bezel pattern, a remarkable remarkable effect that an intended conductive pattern with excellent linearity and no disconnection or short circuit can be obtained. It is supposed to play.
• Patent Document 1 Even when the bezel pattern printing conductive paste described in Patent Document 1 is used, it cannot sufficiently cope with the recent thinning of the conductive pattern.
• the above-mentioned Patent Document 1 also considers the blanket swelling rate of the solvent, but the reason for the preferable numerical range is not clear, and the thinning of the conductive pattern formed by gravure offset printing is optimized. It's hard to say.
• an object of the present invention is to form a fine conductive pattern having sufficient conductivity and good adhesion to a substrate. It is to provide a method for forming a conductive paste and a conductive pattern. More specifically, an object of the present invention is to provide a conductive paste capable of forming a conductive pattern having a line width of 5 ⁇ m or less using gravure offset printing and a method for forming the conductive pattern.
• the present inventor has found that the blanket swelling rate of the solvent used for the conductive paste is extremely small in order to thin the conductive pattern formed by gravure offset printing.
• the inventors have found that setting to a value is extremely effective in achieving the above object, and have reached the present invention.
• the present invention Silver fine particles and an organic solvent
• the organic solvent includes a low swelling organic solvent having a blanket swelling rate of 2.0% or less,
• the content of the low swelling organic solvent is 3.0 to 30 wt%,
• An electrically conductive paste is provided.
• the outermost surface of a printing plate used for gravure offset printing is made of silicone rubber
• the “blanket swelling ratio” in the present invention means a swelling ratio when silicone rubber is immersed in an organic solvent.
• the “blanket swelling rate” is the same as the weight change rate of the blanket (silicone rubber) before and after immersion when the blanket (silicone rubber) is immersed in an organic solvent.
• a blanket silicone rubber
• an organic solvent under room temperature conditions (25 ° C. ⁇ 5 ° C.), taken out after 10 hours and immersed.
• the “blanket swelling rate” can be evaluated. It has been experimentally proved that there is no significant difference in the swelling rate measured for a specific organic solvent in the case of a silicone blanket that is used as a standard for conductive paste printing.
• the conductive paste of the present invention by using a low swelling organic solvent having a blanket swelling rate of 2.0% or less, absorption of the organic solvent into the blanket can be reduced, and the conductive paste on the blanket surface can be reduced. Drying can be greatly suppressed.
• the conductive paste printed in the form of ultrafine lines is very easy to dry and it is difficult to form a good conductive pattern.
• the blanket swelling rate of the organic solvent is 2.0% or less, for example, it is possible to cope with the formation of an ultrafine wire conductive pattern having a line width of 5 ⁇ m or less.
• a more preferable blanket swelling ratio is 0.4% or less.
• the content of the low swelling organic solvent is set to 3.0 to 30 wt%.
• an appropriate coating property fluidity
• a more preferable content of the low swellable organic solvent is 3.0 to 25.0 wt%
• a most preferable content is 3.0 to 20.0 wt%.
• the silver fine particles are preferably silver nanoparticles.
• coarse silver particles it becomes difficult to sinter the silver particles, and good conductivity cannot be imparted to the conductive pattern.
• electroconductivity can be ensured by sintering and contact between silver particles by using silver nanoparticles.
• a silver submicron having a particle size of 0.5 ⁇ 0.3 ⁇ m in a 2 ⁇ m wide recess formed on the surface of a printing plate used for gravure offset printing.
• the particles are filled, only one or two silver submicron particles can be filled in the width direction of the recesses.
• the influence of each silver submicron particle is great, and only one silver submicron particle is detached, resulting in a significant loss of linearity of the thin wire.
• the above-mentioned recesses can be filled with a large number of silver nanoparticles, and since the silver nanoparticles are finely overlapped and arranged, the silver nanoparticles are sintered (necking). It is easy to make. In addition, since the particle size is extremely small, the influence of one silver nanoparticle on print quality can be greatly reduced.
• the particle size and shape of the silver nanoparticles are not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known silver nanoparticles can be used. Specifically, silver nanoparticles having an average particle size of less than 1 ⁇ m can be used, the more preferable average particle size is 1 to 200 nm, and the most preferable average particle size is 2 to 100 nm. If the average particle diameter of the silver nanoparticles is 1 nm or more, the silver fine particles have good low-temperature sinterability, and the production of silver fine particles is practical without increasing the cost. Moreover, if it is 200 nm or less, the dispersibility of silver fine particles does not change easily with time, and is preferable.
• the particle size of the silver nanoparticles may not be constant. Further, as described above, the average particle diameter of the silver nanoparticles is preferably 200 nm or less. However, when the conductive paste contains a dispersing agent or the like, which will be described later, as an optional component, aggregation does not occur. As long as the effect of the invention is not significantly impaired, silver fine particles having an average particle diameter of more than 200 nm may be included. In addition, silver microparticles may be added as necessary.
• the low-swelling organic solvent has a boiling point of 200 ° C. or higher at normal pressure, and the low-swelling organic solvent has a hydroxyl group.
• the boiling point at normal pressure is 200 ° C. or higher, excessive drying on the gravure intaglio is suppressed, and by having a hydroxyl group, dispersion into nanoparticles is improved and the polarity is increased to a blanket. This is because the tendency to suppress the swelling of the resin.
• the present invention also provides: Using gravure offset printing method using gravure plate,
• the gravure plate has a recess filled with a conductive paste for printing on the printing surface,
• the recess corresponds to printing of a fine line pattern having a line width of 10 ⁇ m or less
• Use of the conductive paste according to any one of claims 1 to 3 as the conductive paste for printing There is also provided a method for forming a conductive pattern characterized by:
• the conductive paste of the present invention contains an organic solvent having an extremely low blanket swelling rate of 2.0% or less, the absorption of the organic solvent into the blanket is reduced, and the blanket surface Drying of the conductive paste can be greatly suppressed.
• the conductive paste printed in the form of ultra fine lines is very easy to dry and it is difficult to form a good conductive pattern, but the conductive paste of the present invention Since the blanket swelling rate of the organic solvent is 2.0% or less, for example, it is possible to cope with the formation of a very fine wire conductive pattern having a line width of 5 ⁇ m or less.
• a fine conductive pattern having sufficient conductivity and good adhesion to the substrate can be formed.
• a conductive pattern having a line width of 5 ⁇ m or less can be formed.
• the conductive paste of the present embodiment includes silver fine particles and an organic solvent, and the organic solvent includes a low-swelling organic solvent having a blanket swelling rate of 2.0% or less.
• the average particle size of the silver fine particles in the conductive paste of the present embodiment is not particularly limited as long as the effect of the present invention is not impaired, but the average particle size is less than 1 ⁇ m. It is preferable to use silver nanoparticles. Here, it is preferable to have an average particle size that causes a melting point drop. For example, the average particle size is more preferably 1 to 200 nm, and most preferably 2 to 100 nm. If the average particle diameter of the silver fine particles is 1 nm or more, the silver fine particles have good low-temperature sinterability, and the production of silver fine particles is practical without increasing the cost. Moreover, if it is 200 nm or less, the dispersibility of a silver fine particle does not change easily over time, and it is preferable.
• a metal whose ionization column is more noble than hydrogen that is, gold, copper, platinum, palladium, or the like is added. May be.
• the particle size of the silver fine particles in the conductive paste of the present embodiment may not be constant.
• the metal particle component having various particle sizes can be used as long as it does not cause aggregation and does not significantly impair the effects of the present invention. May be included.
• micron-sized silver particles can be added in combination.
• a favorable conductive path can be obtained by causing the melting point of the nanometer-sized silver particles to drop around the micron-sized silver particles.
• the particle size of the silver fine particles in the conductive paste of the present embodiment can be measured by a dynamic light scattering method, a small-angle X-ray scattering method, and a wide-angle X-ray diffraction method.
• the crystallite diameter determined by the wide-angle X-ray diffraction method is appropriate.
• RINT-UltimaIII manufactured by Rigaku Corporation can be used to measure 2 ⁇ in the range of 30 to 80 ° by the diffraction method.
• the sample may be measured by extending it thinly so that the surface becomes flat on a glass plate having a recess of about 0.1 to 1 mm in depth at the center.
• the crystallite diameter (D) calculated by substituting the half width of the obtained diffraction spectrum into the following Scherrer equation using JADE manufactured by Rigaku Corporation may be used as the particle diameter.
• D K ⁇ / Bcos ⁇
• K Scherrer constant (0.9)
• ⁇ wavelength of X-ray
• B half width of diffraction line
• ⁇ Bragg angle.
• an organic component adheres to at least a part of the surface of the silver fine particles.
• the organic component substantially constitutes an inorganic colloid particle together with the silver fine particles as a so-called dispersant.
• the organic component includes trace organic substances contained as impurities in the silver fine particles from the beginning, trace organic substances adhering to the silver fine particles mixed in the manufacturing process described later, residual reducing agent that could not be removed in the cleaning process, residual dispersant, etc. As described above, it is a concept that does not include organic substances or the like adhered to silver fine particles.
• the “trace amount” is specifically intended to be less than 1% by mass in the inorganic colloidal particles.
• the organic component is an organic substance that can coat silver fine particles to prevent aggregation of the silver fine particles and form inorganic colloidal particles, and the form of the coating is not particularly defined, but in this embodiment, From the viewpoint of dispersibility and electrical conductivity, it is preferable to contain an amine and a carboxylic acid.
• these organic components are chemically or physically bonded to the inorganic particles, it is considered that they are changed to anions and cations. In this embodiment, ions derived from these organic components are used. And organic complexes are also included in the organic components.
• the amine may be linear or branched, and may have a side chain.
• the amine may be a compound containing a functional group other than an amine such as a hydroxyl group, a carboxyl group, an alkoxy group, a carbonyl group, an ester group, or a mercapto group. Moreover, the said amine may be used independently, respectively and may use 2 or more types together. In addition, the boiling point at normal pressure is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.
• the conductive paste of the present embodiment may contain a carboxylic acid in addition to the above amine as long as the effects of the present invention are not impaired.
• the carboxyl group in one molecule of the carboxylic acid has a relatively high polarity and tends to cause an interaction due to a hydrogen bond, but a portion other than these functional groups has a relatively low polarity. Furthermore, the carboxyl group tends to exhibit acidic properties.
• carboxylic acid compounds having at least one carboxyl group can be widely used, and examples thereof include formic acid, oxalic acid, acetic acid, hexanoic acid, acrylic acid, octylic acid, and oleic acid.
• a part of carboxyl groups of the carboxylic acid may form a salt with a metal ion.
• 2 or more types of metal ions may be contained.
• the carboxylic acid may be a compound containing a functional group other than a carboxyl group, such as an amino group, a hydroxyl group, an alkoxy group, a carbonyl group, an ester group, or a mercapto group.
• the number of carboxyl groups is preferably equal to or greater than the number of functional groups other than carboxyl groups.
• the said carboxylic acid may be used independently, respectively and may use 2 or more types together.
• the boiling point at normal pressure is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.
• amines and carboxylic acids form amides. Since the amide group is appropriately adsorbed on the surface of the silver fine particles, the organic component may contain an amide group.
• the content of the organic component in the inorganic colloid in the conductive paste of the present embodiment is preferably 0.5 to 50% by mass. If the organic component content is 0.5% by mass or more, the storage stability of the resulting bonding composition tends to be improved, and if it is 50% by mass or less, the conductivity of the conductive pattern tends to be good. is there. A more preferable content of the organic component is 1 to 30% by mass, and a more preferable content is 2 to 15% by mass.
• composition ratio (mass) when the amine and carboxylic acid are used in combination can be arbitrarily selected within the range of 1/99 to 99/1, preferably 20/80 to 98/2, The ratio is preferably 30/70 to 97/3.
• amine or carboxylic acid a plurality of types of amines or carboxylic acids may be used.
• the conductive paste of the present embodiment is provided with functions such as appropriate viscosity, adhesion, drying property, and printability according to the intended use within a range not impairing the effects of the present invention. Therefore, a polymer dispersant, for example, an oligomer component that serves as a binder, a resin component, an organic solvent (a part of the solid content may be dissolved or dispersed), a surfactant, a thickener, or a surface tension. You may add arbitrary components, such as a regulator. Such optional components are not particularly limited.
• polymer dispersant a commercially available polymer dispersant can be used.
• examples of the commercially available polymer dispersant include, for example, Solsperse 11200, Solsperse 13940, Solsperse 16000, Solsperse 17000, Solsperse 18000, Solsperse 20000, Solsperse 24000, Solsperse 26000, Solsperse 27000, Solsperse.
• the content of the polymer dispersant is preferably 0.1 to 15% by mass.
• the content of the polymer dispersant is 0.1% or more, the dispersion stability of the resulting bonding composition is improved. However, when the content is too large, the dispersion stability is lowered. From such a viewpoint, the more preferable content of the polymer dispersant is 0.03 to 3% by mass, and still more preferable content is 0.05 to 2% by mass.
• the resin component examples include polyester resins, polyurethane resins such as blocked isocyanate, polyacrylate resins, polyacrylamide resins, polyether resins, melamine resins, and terpene resins. May be used alone or in combination of two or more.
• the printing material is, for example, polyethylene terephthalate (PET), as a resin component, polyvinyl alcohol, polyvinyl pyrrolidone, vinyl chloride-vinyl acetate copolymer having good adhesion to PET itself, It is preferable to use one selected from the group consisting of polyvinyl acetoacetal and polyvinyl butyral.
• examples of such ketone-formaldehyde condensates and hydrogenated products include Evonik Degussa Japan Co., Ltd. TEGO (registered trademark) VariPlus series (SK, AP, etc.), and vinyl chloride-vinyl acetate copolymers include Nisshin Chemical.
• Solvain (registered trademark) series (Solvine AL, etc.) manufactured by Kogo Oil Co., Ltd. is used as polyvinyl acetoacetal and polyvinyl butyral. Etc.).
• polyvinylpyrrolidone is preferably used because it has high solubility in highly polar polyhydric alcohols (particularly diol solvents) and can be dissolved well in solvents such as esters and ketones.
• the thickener examples include clay minerals such as clay, bentonite or hectorite, for example, emulsions such as polyester emulsion resins, acrylic emulsion resins, polyurethane emulsion resins or blocked isocyanates, methyl cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose. , Cellulose derivatives such as hydroxypropylcellulose and hydroxypropylmethylcellulose, polysaccharides such as xanthan gum and guar gum, and the like. These may be used alone or in combination of two or more.
• clay minerals such as clay, bentonite or hectorite
• emulsions such as polyester emulsion resins, acrylic emulsion resins, polyurethane emulsion resins or blocked isocyanates, methyl cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose.
• Cellulose derivatives such as hydroxypropylcellulose and hydroxypropylmethylcellulose, polysacc
• a surfactant different from the above organic components may be added.
• the coating surface becomes rough and the solid content tends to be uneven due to the difference in volatilization rate during drying.
• the surfactant that can be used in the present embodiment is not particularly limited, and any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used, for example, an alkylbenzene sulfonate. A quaternary ammonium salt etc. are mentioned. Since the effect can be obtained with a small addition amount, a fluorosurfactant is preferable.
• the dispersion medium contains a low-swelling organic solvent having a blanket swelling rate of 2% or less.
• Various solvents can be used as the low-swelling organic solvent having a blanket swelling rate of 2% or less as long as the effects of the present invention are not impaired.
• only a low-swelling organic solvent having a blanket swelling rate of 2% or less may be used as the dispersion medium.
• the dispersion medium is mixed with a solvent having a blanket swelling rate of more than 2%. , May be used as a mixed solvent.
• the combination of mixing is not specifically limited, You may mix multiple types of solvent.
• a solvent having a hydroxyl group as a functional group is preferable.
• examples thereof include polyhydric alcohols having a plurality of hydroxyl groups and other monovalent alcohol solvents. Can do. These solvents may be used alone or in combination of two or more.
• the content of the low swelling organic solvent is 3.0 to 30 wt%.
• the content ratio of the low-swelling organic solvent is 3.0 wt% or more, for example, drying at the time of ultrafine wire printing of 5 ⁇ m or less can be suppressed, and by setting it to 30 wt% or less, the spread at the time of printing can be suppressed. Can be prevented.
• the content is 3.0 to 25.0 wt%, and the most preferable content is 3.0 to 20.0 wt%.
• the low-swelling organic solvent has a boiling point of 200 ° C. or higher at normal pressure, and the low-swelling organic solvent has a hydroxyl group.
• the boiling point at normal pressure is 200 ° C. or higher
• the boiling point at normal pressure is 200 ° C. or higher, so that excessive drying on the gravure intaglio is suppressed, and by having a hydroxyl group, the nanoparticles are converted into nanoparticles. This is because the dispersion becomes good and the swelling to the blanket tends to be suppressed by increasing the polarity.
• An organic solvent having a blanket swelling rate of 2% or less (low swelling organic solvent)
• polyhydric alcohols having 2 to 3 hydroxyl groups include glycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, ethylene glycol, diethylene glycol, 1,2-butanediol, and propylene glycol. Examples include 2-methylpentane-2,4-diol.
• Examples of the solvent having a monovalent alcohol and a swelling ratio of 2% or less include butyl triglycol, isobutyl diglycol, 2-butoxyethanol, 3-methoxy-3-methylbutanol, 2- (2-methoxyethoxy) ethanol, 2- (2-hexyloxyethoxy) ethanol and the like can be mentioned, but 2,4-diethyl-1,5-pentanediol and 3-methyl-1,5-pentanediol having a boiling point exceeding 200 ° C. under normal pressure.
• examples of the organic solvent having a high swelling ratio of blanket swelling ratio of more than 2% include glycol ethers, glycol esters, terpene solvents, hydrocarbon solvents, alcohol solvents, etc. You may use independently and may use 2 or more types together.
• Examples of the organic solvent having a blanket swelling rate exceeding 2% include tripropylene glycol-n-butyl ether, butyl carbitol, diethylene glycol monomethyl ether, tripropylene glycol methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene.
• Examples of the aliphatic hydrocarbon include tetradecane, octadecane, heptamethylnonane, tetramethylpentadecane, hexane, heptane, octane, nonane, decane, tridecane, methylpentane, normal paraffin, and isoparaffin. There may be mentioned hydrocarbons.
• examples of the cyclic hydrocarbon include toluene, xylene and the like.
• examples of the alicyclic hydrocarbon include limonene, dipentene, terpinene, terpinene (also referred to as terpinene), nesol, sinene, orange flavor, terpinolene, terpinolene (also referred to as terpinolene), ferrandylene, mentadiene, teleben, Dihydrocymene, moslene, isoterpinene, isoterpinene (also referred to as isoterpinene), clitomen, kautssin, cajeptene, oilimene, pinene, turpentine, menthane, pinane, terpene, cyclohexane, and the like can be given.
• Alcohol is a compound containing one or more hydroxyl groups in the molecular structure, and examples thereof include aliphatic alcohols, cyclic alcohols and alicyclic alcohols, and each may be used alone or in combination of two or more. . Moreover, a part of hydroxyl group may be induced
• aliphatic alcohol examples include heptanol, octanol (1-octanol, 2-octanol, 3-octanol, etc.), decanol (1-decanol, etc.), lauryl alcohol, tetradecyl alcohol, cetyl alcohol, 2-ethyl-1- Examples thereof include saturated or unsaturated C6-30 aliphatic alcohols such as hexanol, octadecyl alcohol, hexadecenol and oleyl alcohol.
• cyclic alcohols include cresol and eugenol.
• alicyclic alcohols such as terpene solvents include cycloalkanols such as cyclohexanol, terpineols (including ⁇ , ⁇ , ⁇ isomers, or any mixture thereof), and terpene alcohols such as dihydroterpineol. (Monoterpene alcohol, etc.), dihydroterpineol, myrtenol, sobrerol, menthol, carveol, perillyl alcohol, pinocarveol, sobrerol, berbenol and the like.
• the viscosity of the conductive paste of the present embodiment is preferably prepared for gravure offset printing.
• Gravure offset printing is a printing method that can be applied to a wide viscosity range, and is often used in the range of 500 cP to 100,000 cP, but is often expressed in terms of shear viscosity.
• the viscosity can be measured with a cone plate viscometer (for example, a rheometer MCR301 manufactured by Anton Paar). For example, the viscosity at a measurement temperature of 25 ° C. and a cone rotation speed of 50 rpm can be employed.
• the viscosity of the electroconductive paste of the present embodiment is 0.5 Pa ⁇ s or higher .
• a silver fine particle dispersion is prepared.
• the conductive paste of this embodiment can be obtained by mixing the silver fine particle dispersion, the organic solvent, and the various components described above.
• the silver fine particle dispersion is prepared by a first pre-process for preparing a mixed liquid of a silver compound that can be decomposed by reduction to produce metallic silver and an amine, and the silver compound in the mixed liquid. It is preferable to include a second pre-process that generates silver fine particles in which amine is attached to at least a part of the surface by reduction.
• the first pre-process it is preferable to add 2 mol or more of amine to 1 mol of metal silver.
• an appropriate amount of amine can be attached to the surface of the silver fine particles produced by reduction, and various dispersion media can be attached to the silver fine particles (silver nanoparticles).
• silver nanoparticles can be imparted with excellent dispersibility and low-temperature sinterability.
• the particle size of the silver fine particles obtained is a nanometer size that causes a melting point drop depending on the composition of the liquid mixture in the first pre-process and the reduction conditions (for example, heating temperature and heating time) in the second pre-process.
• the thickness is 1 to 200 nm.
• micron-sized particles may be included as necessary.
• the method for taking out the silver fine particles from the silver fine particle dispersion obtained in the second pre-process is not particularly limited, and examples thereof include a method for washing the silver fine particle dispersion.
• silver nitrate, silver sulfate, silver chloride examples thereof include silver salts such as silver oxide, silver acetate, silver oxalate, silver formate, silver nitrite, silver chlorate and silver sulfide. These are not particularly limited as long as they can be reduced, and may be dissolved in an appropriate solvent or may be used as dispersed in a solvent. These may be used alone or in combination.
• the method for reducing these silver compounds in the raw material liquid is not particularly limited.
• a method using a reducing agent a method of irradiating light such as ultraviolet rays, an electron beam, ultrasonic waves or thermal energy, a method of heating, etc. Is mentioned.
• a method using a reducing agent is preferable from the viewpoint of easy operation.
• Examples of the reducing agent include amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine; for example, hydrogen compounds such as sodium borohydride, hydrogen iodide, and hydrogen gas; for example, carbon monoxide.
• amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine
• hydrogen compounds such as sodium borohydride, hydrogen iodide, and hydrogen gas
• carbon monoxide for example, carbon monoxide.
• Oxides such as sulfurous acid; for example, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, iron sulfide, tin acetate, tin chloride, tin diphosphate, tin oxalate, tin oxide, sulfuric acid
• Low valent metal salts such as tin; for example, sugars such as ethylene glycol, glycerin, formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid, D-glucose, etc.
• sugars such as ethylene glycol, glycerin, formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid, D-glucose, etc.
• light and / or heat may be added to promote the reduction reaction.
• organic component, solvent and reducing agent for example, the above metal salt is dissolved in an organic solvent (for example, toluene) to form a metal salt.
• organic solvent for example, toluene
• examples include a method of preparing a solution, adding an amine as a protective dispersant or a protective dispersant having an acid value to the metal salt solution, and then gradually dropping the solution in which the reducing agent is dissolved.
• the dispersion liquid containing silver fine particles coated with an amine or a protective dispersant having an acid value obtained as described above in addition to the silver fine particles, a counter ion of a metal salt, a residue of a reducing agent or a dispersant Exist, and the electrolyte concentration and organic substance concentration of the whole liquid tend to be high.
• the liquid in such a state is likely to precipitate due to the coagulation of the metal particles due to high electrical conductivity.
• the conductivity of the metal salt may deteriorate if the counter ion of the metal salt, the residue of the reducing agent, or an excessive amount of dispersant remaining in the amount necessary for dispersion remains. Therefore, by washing the solution containing silver fine particles to remove excess residues, silver fine particles coated with an organic substance can be obtained with certainty.
• washing method for example, a dispersion containing silver fine particles coated with an organic component is allowed to stand for a certain period of time, and after removing the resulting supernatant, a solvent for precipitating silver fine particles (for example, water, methanol, Methanol / water mixed solvent, etc.) is added and stirred again, and the process of removing the supernatant liquid after standing for a certain period of time is repeated several times, the method of performing centrifugation instead of the above standing, Examples thereof include a desalting method using a filtration device, an ion exchange device, and the like. By removing an excess residue and removing the organic solvent by such washing, silver fine particles in which at least a part of the surface is coated with an organic component can be obtained.
• a solvent for precipitating silver fine particles for example, water, methanol, Methanol / water mixed solvent, etc.
• the conductive paste can be obtained by dispersing silver fine particles or the like coated with the organic component in a dispersion medium containing a low-swelling organic solvent having a blanket swelling rate of 2% or less (low swelling property).
• the organic solvent content is 3.0 to 30 wt%.
• the method for mixing the silver fine particles and the dispersion medium is not particularly limited, and can be performed by a conventionally known method using a stirrer or a stirrer. An ultrasonic homogenizer with an appropriate output may be applied by stirring with a spatula or the like.
• Silver fine particles may be produced by the second step of producing the produced silver fine particles.
• a silver compound such as silver oxalate containing silver and a complex compound produced from an amine are heated to agglomerate atomic silver produced by decomposing a metal compound such as oxalate ion contained in the complex compound By doing so, silver fine particles protected by an amine protective film can be produced.
• the metal amine complex decomposition method for producing silver fine particles coated with amine by thermally decomposing a complex compound of silver compound in the presence of amine decomposition of silver amine complex which is a single kind of molecule is performed. Since atomic silver is generated by the reaction, it is possible to generate atomic silver uniformly in the reaction system, and the reaction is configured as compared to the case of generating silver atoms by reaction between multiple components. Inhomogeneity of the reaction due to fluctuations in the composition of the components is suppressed, which is particularly advantageous when a large amount of silver powder is produced on an industrial scale.
• an amine molecule is coordinated to the silver atom to be generated, and the movement of the silver atom during aggregation is controlled by the action of the amine molecule coordinated to the silver atom. Inferred.
• the metal amine complex decomposition method it is possible to produce metal particles that are very fine and have a narrow particle size distribution.
• amine molecules form a relatively weak coordination bond on the surface of the silver fine particles to be produced, and these form a dense protective film on the surface of the silver fine particles, so that the storage stability is excellent. It becomes possible to produce organic coated silver fine particles having a clean surface.
• the amine molecules forming the film can be easily detached by heating or the like, silver fine particles that can be sintered at a very low temperature can be produced.
• the amine is mixed with the dispersant having an acid value constituting the coating of the coated silver fine particles. This facilitates the generation of a complex compound such as a complex compound, and makes it possible to produce the complex compound by mixing in a short time.
• coated silver nanoparticles having characteristics corresponding to various applications can be produced.
• a fine conductive pattern can be formed by gravure offset printing using a gravure plate. More specifically, by using the gravure plate having a concave portion (a concave portion corresponding to a line width of 10 ⁇ m or less) filled with the conductive paste for printing on the printing surface, printing the conductive paste of the present embodiment, A fine conductive pattern having sufficient conductivity and good adhesion to the substrate can be formed. Further, by forming the concave portion in a size and shape corresponding to a line width of 5 ⁇ m or less, an ultrafine conductive pattern having a line width of 5 ⁇ m or less can be formed.
• the conductive pattern forming method of the present embodiment includes an application step of applying the conductive paste to a base material, and firing the conductive paste applied to the base material at a temperature of less than 140 ° C. (preferably 120 ° C. or less).
• a good conductive pattern can be formed on the surface of the substrate by the firing step of forming the conductive pattern.
• the conductive paste of the present embodiment described above is used as the conductive paste in the coating step, even if the conductive ink applied to the base material is baked at a temperature of less than 140 ° C. in the baking step, A conductive pattern having excellent conductivity can be formed.
• a conductive paste is applied on a blanket to form a conductive paste application surface.
• a silicone blanket made of silicone is preferable.
• the silicone blanket may include, for example, Syl Blanc series from Kinyo Co., Ltd. and # 700-STD from Fujikura Rubber Industry.
• the conductive paste coating surface is formed on the surface of the blanket, and then the low boiling point solvent is volatilized and absorbed in the blanket by leaving it for a short time.
• the viscosity of the ink is increased.
• the conductive paste of this embodiment uses an organic solvent with a blanket swelling rate of 2.0% or less, absorption of the organic solvent into the blanket is reduced, and the blanket surface Drying of the conductive paste can be significantly suppressed.
• the conductive paste printed in the form of ultra fine lines is very easy to dry and it is difficult to form a good conductive pattern, but the conductive paste of the present invention Since the blanket swelling rate of the organic solvent is 2.0% or less, for example, it is possible to cope with the formation of a very fine wire conductive pattern having a line width of 5 ⁇ m or less.
• the substrate that can be used in the present embodiment is not particularly limited as long as it has at least one main surface that can be mounted with a conductive pattern by applying a conductive paste and firing it by heating. Although it is not, it is preferable that the substrate is excellent in heat resistance. Further, as described above, the conductive paste of this embodiment has a conductive pattern that has sufficient conductivity even when heated and baked at a lower temperature than conventional conductive inks and conductive pastes. Therefore, it is possible to use a base material having a lower heat-resistant temperature than the conventional one in a temperature range higher than this low firing temperature.
• Examples of the material constituting such a base material include polyamide (PA), polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and the like.
• Polyester, polycarbonate (PC), polyethersulfone (PES), vinyl resin, fluororesin, liquid crystal polymer, ceramics, glass or metal can be used.
• the substrate may have various shapes such as a plate shape or a strip shape, and may be rigid or flexible. The thickness of the substrate can also be selected as appropriate. In order to improve adhesiveness or adhesion, or for other purposes, a substrate on which a surface layer is formed or a substrate that has been subjected to a surface treatment such as a hydrophilic treatment may be used.
• the coated film after coating as described above can be baked by heating to a temperature of less than 140 ° C. (preferably 120 ° C. or less) to obtain a conductive pattern (substrate with a conductive pattern).
• the method for firing is not particularly limited.
• the temperature of the conductive paste applied or drawn on the substrate using a conventionally known gear oven or the like is less than 140 ° C. (preferably 120 ° C. or less).
• the conductive pattern can be formed by firing so as to be.
• the lower limit of the firing temperature is not necessarily limited, and is a temperature at which a conductive pattern can be formed on a substrate, and the temperature at which the organic components and the like can be removed by evaporation or decomposition within a range not impairing the effects of the present invention. (A part may remain within a range that does not impair the effects of the present invention, but it is desirable that all be removed desirably).
• a conductive pattern that exhibits high conductivity can be formed even by low-temperature heat treatment at about 120 ° C., so that the conductive pattern is also formed on a relatively heat-sensitive substrate. Can be formed. Further, the firing time is not particularly limited, and a conductive pattern can be formed on the substrate according to the firing temperature.
• surface treatment of the base material may be performed in order to further improve the adhesion between the base material and the conductive pattern.
• the surface treatment method include a method of performing dry treatment such as corona treatment, plasma treatment, UV treatment, and electron beam treatment, and a method of previously providing a primer layer and a conductive paste receiving layer on a substrate.
• the film thickness of the conductive pattern of the present embodiment thus obtained is, for example, about 0.1 to 5 ⁇ m, more preferably 0.1 to 1 ⁇ m.
• a conductive pattern having sufficient conductivity can be obtained even if the thickness is about 0.1 to 5 ⁇ m.
• the volume resistance value of the conductive pattern of this embodiment is 50 ⁇ ⁇ cm or less.
• Example 1 9.0 g of 3-methoxypropylamine (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) and 0.2 g of DISPERMYK-102 (BIC Chemie Co., Ltd.), which is a polymer dispersant, were mixed and mixed into a magnetic stirrer. Stir well to produce an amine mixture. Next, 3.0 g of silver oxalate was added while stirring. After the addition of silver oxalate, stirring was continued at room temperature to change the silver oxalate to a viscous white substance, and stirring was terminated when the change was found to be apparently finished.
• 3-methoxypropylamine first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.
• DISPERMYK-102 BIC Chemie Co., Ltd.
• the obtained mixed solution was transferred to an oil bath and heated and stirred at 120 ° C. Immediately after the start of stirring, a reaction involving the generation of carbon dioxide started, and then stirring was performed until the generation of carbon dioxide was completed, thereby obtaining a suspension in which silver fine particles were suspended in the amine mixture.
• Polyvinylpyrrolidone K30 (Wako Pure Chemical Industries, Ltd.) as a resin material is added to 17 parts by weight of 1.3-butylene glycol ((Reagent Grade 1 manufactured by Wako Pure Chemical Industries, Ltd.) as an organic solvent with respect to 80 parts by weight of silver nanoparticle slurry. 20 parts by weight of a mixed solution in which 3 parts by weight of a reagent manufactured by Co., Ltd. was dissolved, and mixed with a stir bar, mixed and deformed with a rotation / revolution mixer to obtain an implementation conductive paste 1.
• 1.3-butylene glycol ((Reagent Grade 1 manufactured by Wako Pure Chemical Industries, Ltd.) as an organic solvent with respect to 80 parts by weight of silver nanoparticle slurry.
• a blanket is used.
• the blanket include a sheet having a layer structure such as a silicone rubber layer and a sponge layer, and are usually used in a state of being wound around a rigid cylinder called a blanket cylinder.
• the blanket used for the measurement of the blanket swelling ratio is a blanket that is generally used at the time of printing the conductive paste.
• the organic solvent shown in Table 1 was evaluated for blanket swelling rate, cut into 1 cm square, and blanket A after measurement was completely immersed in various organic solvents (20 g). After 10 hours, the blanket was taken out from the organic solvent and adhered. The solvent was wiped off, and the weight was measured again within 1 minute, and the weight increase rate before and after immersion was determined. The obtained values are shown in Table 1. The immersion was performed under room temperature conditions (25 ° C. ⁇ 5 ° C.). Table 1 also shows the boiling point of the organic solvent.
• the line linearity is particularly excellent, “ ⁇ ” when there is no disconnection, “ ⁇ ” when there is no line, “ ⁇ ” when there is no disconnection, inferior line linearity, and disconnection
• ⁇ when there was no part was evaluated as “ ⁇ ”
• the line linearity was inferior, and the part where there was a broken part was evaluated as “ ⁇ ”.
• ⁇ indicates that there is no line expansion
• ⁇ indicates that there is a slight line expansion
• x indicates that there is a line expansion and an obvious line weight.
• volume resistance value A silver fine particle dispersion was formed on a PET substrate by gravure offset printing (width 1 mm, length 1.5 cm), and heated and fired in a gear oven at 120 ° C. for 30 minutes.
• the conductive pattern was formed by sintering.
• the resistance value of the conductive pattern is measured at both ends of the printed wiring with “Digital Multimeter PM-3” manufactured by Sanwa Denki Keiki Co., Ltd., and the thickness is measured by the shape measuring laser microscope “VK-X100” manufactured by Keyence Corporation. ”And measured.
• the volume resistance value was converted from the distance between the measurement terminals and the thickness of the conductive coating.
• the obtained results are shown in Table 2.
• Formula: (volume resistance value ⁇ v) (resistance value R) ⁇ (film width w) ⁇ (film thickness t) / (distance L between terminals)
• Adhesion test Cell tape (registered trademark) was affixed to the printed wiring on the PET substrate used for the printability evaluation, and evaluation was performed based on the state of breakage when peeled off. Specifically, the tape was strongly rubbed against five places of the printed wiring, and was peeled off in the vertical direction for evaluation. The case where the number of peeled sheets is 0 to 1 is “ ⁇ ”, the case of 2 to 3 sheets is “ ⁇ ”, and the case of 4 to 5 sheets is “ ⁇ ”. I counted it as one sheet. The obtained results are shown in Table 2.
• Example 2 The organic solvent added to 80 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1 was changed from 1.3-butylene glycol (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) to 2 ethyl-1,3. -Conductive paste 2 was obtained in the same manner as in Example 1, except that the mixture was changed to 17 parts by weight of hexanediol isomer mixture (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.). Further, the conductive paste 2 was evaluated in the same manner as in Example 1, and the results obtained are shown in Table 2.
• Example 3 2-ethyl-1,3-hexanediol isomer mixture (manufactured by Wako Pure Chemical Industries, Ltd.) with respect to 80 parts by weight of submicron silver (manufactured by Rare Metal Materials Laboratory, Inc., particle size distribution 0.2 ⁇ m to 1.0 ⁇ m) First grade reagent) 16 parts by weight 3 parts by weight of resin material SREC KS-10 (manufactured by Sekisui Chemical Co., Ltd.), 0.5 parts by weight of thixotropic CrytassenseMP (manufactured by CLODA), and SOLPERSE 41000 as a polymer dispersant
• Example conductive paste 3 was obtained in the same manner as Example 1 except that 20 parts by weight of a mixed solution in which 0.5 part by weight (manufactured by Nippon Lubrizol Co., Ltd.) was added was added. Further, the conductive paste 3 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• Example 4 A total of 80 parts by weight of 60 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1 and 20 parts by weight of submicron silver (particle size distribution 0.2 ⁇ m to 1.0 ⁇ m, manufactured by Rare Metals Laboratory) are used.
• Example conductive paste 4 was obtained in the same manner as Example 3 except for the above. Further, the conductive paste 4 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• Example 5 The organic solvent to be added to 82 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1 was a mixture of 2-ethyl-1,3-hexanediol isomers (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) Conductive paste 5 in the same manner as in Example 2, except that the mixed solvent was changed from 17 parts by weight to 3 parts by weight of Kyowadiol PD-9 (manufactured by KH Neochem) and 12 parts by weight of terpineol (manufactured by Yasuhara Chemical). Got. Further, the conductive paste 5 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• 2-ethyl-1,3-hexanediol isomers (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.)
• Conductive paste 5 in the same manner as in Example 2, except that the mixed solvent was changed from 17 parts by weight to 3 parts by weight of Kyowad
• Example 6 The organic solvent to be added is 66 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1, and the organic solvent to be added is a mixture of 2-ethyl-1,3-hexanediol isomers (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) A total of 34 parts by weight of a mixed solution in which 3 parts by weight of polyvinyl pyrrolidone K30 (made by Wako Pure Chemical Industries, Ltd.) as a resin material and 1 part by weight of CrytasenseMP (made by CLODA) as a thixotropic agent were dissolved in 30 parts by weight.
• Example conductive paste 6 was obtained in the same manner as Example 1 except for the above. In addition, the conductive paste 6 was evaluated in the same manner as in Example 1, and the results obtained are shown in Table 2.
• Example 7 The organic solvent added to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 1 was a mixture of 2-ethyl-1,3-hexanediol isomers (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.)
• Example conductive paste 7 was obtained in the same manner as Example 2 except that 17 parts by weight was changed to 17 parts by weight of butyl triglycol (a reagent manufactured by Wako Pure Chemical Industries, Ltd.). Further, the conductive paste 7 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• Example 8 With respect to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 1, the resin adhesion material to be added was 3.0 parts by weight of Polyvinylpyrrolidone K30 (a reagent manufactured by Wako Pure Chemical Industries, Ltd.).
• Example 10 Conductive paste 8 was obtained in the same manner as Example 2 except that it was changed to 3.0 parts by weight (reagent manufactured by Wako Pure Chemical Industries, Ltd.). Further, the conductive paste 8 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• Example 9 The organic solvent to be added is 12 parts by weight of terpineol (manufactured by Yashara Chemical Co., Ltd.) to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 5, and then Tersolve TOE-100 (manufactured by Nippon Terpene Chemical Co., Ltd.) 12.0 Except having changed into the weight part, it carried out similarly to Example 2, and obtained the implementation electroconductive paste 9.
• FIG. In addition, the conductive paste 9 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2.
• Comparative example 1 The organic solvent added to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 1 was a mixture of 2-ethyl-1,3-hexanediol isomers (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) Comparative conductive paste 1 was obtained in the same manner as in Example 2 except that 17 parts by weight was changed to 17 parts by weight of octanol (a reagent manufactured by Wako Pure Chemical Industries, Ltd.). Further, the comparative conductive paste 1 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3.
• Comparative example 2 With respect to 80 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1, the organic solvent to be added was a mixture of 2-ethyl-1,3-hexanediol isomers (reagent grade 1 manufactured by Wako Pure Chemical Industries, Ltd.). ) Comparative conductive paste 2 was obtained in the same manner as in Example 2 except that 17 parts by weight was changed to 17 parts by weight of terpineol (manufactured by Yasuhara Chemical Co., Ltd.). Further, the comparative conductive paste 2 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3.
• Comparative Example 3 The organic solvent added to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 1 was a mixture of 2-ethyl-1,3-hexanediol isomers (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) Comparative conductive paste 3 was obtained in the same manner as in Example 2 except that 17 parts by weight was changed to 17 parts by weight of Tersolve TOE-100 (manufactured by Nippon Terpene Chemical Co., Ltd.). In addition, the comparative conductive paste 3 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3.
• Comparative Example 4 >> The silver nanoparticle slurry obtained by the same method as in Example 1 is added in an amount of 66 to 65 parts by weight, and the organic solvent to be added is a mixture of 2 ethyl-1,3-hexanediol isomers (manufactured by Wako Pure Chemical Industries, Ltd.). Reagent grade 1) Comparative conductive paste 4 was obtained in the same manner as in Example 6 except that 30 parts by weight was changed to 31 parts by weight. The comparative conductive paste 4 was evaluated in the same manner as in Example 1, and the results obtained are shown in Table 3.
• Comparative Example 5 The organic solvent added to 80 parts by weight of the silver nanoparticle slurry obtained by the same method as in Example 1 was a mixture of 2-ethyl-1,3-hexanediol isomers (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) Comparative conductive paste 5 was obtained in the same manner as in Example 2 except that 17 parts by weight was changed to 17 parts by weight of 2-methyl-2,4-pentanediol (first grade reagent manufactured by Wako Pure Chemical Industries, Ltd.). It was. In addition, the comparative conductive paste 5 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3.
• Comparative Example 6 For 82 parts by weight of the silver nanoparticle slurry obtained in the same manner as in Example 1, 3 parts by weight of Kyowadiol PD-9 (KH Neochem) was changed to 2 parts by weight, and terpineol (Yasuhara Chemical) was used. Comparative conductive paste 6 was obtained in the same manner as in Example 6 except that a mixed solvent in which 12 parts by weight was changed to 13 parts by weight was used. Further, the comparative conductive paste 6 was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3.
• the conductive pastes 1 to 9 which are conductive pastes of the present invention have good dispersibility, and in addition to these conductive pastes, A conductive pattern having a width of 5 ⁇ m or less (5 ⁇ m and 3 ⁇ m) is obtained. Moreover, the said electroconductive pattern has the outstanding adhesiveness with a base material, and high electroconductivity.
• Example 5 Even when a solvent having a blanket swelling rate of more than 2.0% was used, a solvent having a blanket swelling rate of 2.0% or less was used. It can be seen that fine line printing is possible by containing 0 wt% or more.
• Example 6 Comparative Example 4
• 30 wt% of a solvent having a blanket swelling rate of 2.0% or less is added, even when a thixotropic agent is added in a range where the conductivity is less affected, the viscosity is increased.
• the addition amount exceeds 31.0 wt%, it is understood that the line spread becomes larger and the line becomes thicker.
• Comparative Example 5 Furthermore, it can be seen from Comparative Example 5 that even when a solvent having a blanket swelling rate of 2.0% or less is used, if the boiling point is lower than 200 ° C., it cannot be used for thin line printing with a line width of 3 ⁇ m.

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