WO2016084312A1 - Conductive ink - Google Patents

Conductive ink Download PDF

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Publication number
WO2016084312A1
WO2016084312A1 PCT/JP2015/005577 JP2015005577W WO2016084312A1 WO 2016084312 A1 WO2016084312 A1 WO 2016084312A1 JP 2015005577 W JP2015005577 W JP 2015005577W WO 2016084312 A1 WO2016084312 A1 WO 2016084312A1
Authority
WO
WIPO (PCT)
Prior art keywords
silver
conductive ink
transfer printing
silver fine
solvent
Prior art date
Application number
PCT/JP2015/005577
Other languages
French (fr)
Japanese (ja)
Inventor
祐樹 新谷
Original Assignee
バンドー化学株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by バンドー化学株式会社 filed Critical バンドー化学株式会社
Priority to KR1020177016437A priority Critical patent/KR102056972B1/en
Priority to CN201580061233.5A priority patent/CN107109095B/en
Priority to JP2016520173A priority patent/JP6101403B2/en
Publication of WO2016084312A1 publication Critical patent/WO2016084312A1/en

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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
    • 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 ink used for forming a wiring or an electrode pattern of a semiconductor integrated circuit or the like and capable of forming a wiring or an electrode pattern on an organic thin film transistor substrate. More specifically, the present invention relates to a conductive ink that can be suitably used for forming a wiring or an electrode pattern using a transfer printing method including a reverse printing method.
  • Patent Document 1 a conductive ink for forming a fine conductive film pattern by a letterpress reverse printing method has been proposed. Specifically, a substantial effect for forming a conductive film pattern by a letterpress reverse printing method is proposed.
  • a conductive ink which does not contain a binder component, and has a volume average particle size (Mv) of 10 to 700 nm, a conductive particle, a release agent, a surface energy adjusting agent, a solvent component as essential components, and a solvent component at 25 ° C.
  • Mv volume average particle size
  • An electrically conductive ink is disclosed.
  • a fine conductive film pattern can be stably formed without a transfer defect by a letterpress reverse printing method.
  • silver is used as conductive particles
  • it is excellent in transferability. It becomes possible to form a fine pattern.
  • This ink has appropriate wettability and releasability on the surface of the silicone blanket by adjusting the dynamic surface tension to an appropriate range.
  • the ink disclosed in Patent Document 2 is mainly suitable for a color filter constituting a liquid crystal display and cannot be used as it is for a conductive ink suitable for a transfer printing method such as a reverse printing method. Since a relatively large amount of the solvent for dissolving the resin is contained, it is necessary to dry the surface of the silicone blanket for a relatively long time after coating, and there is a problem in that the printing tact is relatively long.
  • an object of the present invention has been made in view of the above-described problems of the prior art, and is a conductive ink for transfer printing that can be suitably used for a transfer printing method including a reverse printing method.
  • An object of the present invention is to provide a conductive ink for transfer printing, which can fire a conductive film pattern having good conductivity and good adhesion to a substrate at a low temperature.
  • the present inventor is a conductive ink for transfer printing that can be suitably used for transfer printing methods including reversal printing methods, etc., and has sufficient conductivity and substrate.
  • a conductive ink for transfer printing that can be baked at a low temperature
  • a conductive film pattern having good adhesiveness with a suitable amount of metal particles and a high boiling point solvent having a specific hydroxyl group may be included.
  • the inventors have found that the present invention is extremely effective in achieving the above-described object, and have reached the present invention.
  • Metal particles A solvent comprising ethanol; Containing 0.1 to 3.0% by mass of a high-boiling solvent having a hydroxyl group, A conductive ink for transfer printing is provided.
  • Reversal printing method is a portion in which ink is applied onto a blanket such as a silicone resin to form an ink application surface, and a relief plate for removing a non-image part is pressed on the ink application surface to contact the relief plate After the ink is removed from the blanket, the ink remaining on the blanket is transferred to a printing medium.
  • the high boiling point solvent contains 1,3-butylene glycol, 2,4-diethyl-1,5-pentanediol or octanediol.
  • the conductive ink for transfer printing of the present invention further contains hydrofluoroether.
  • the conductive ink for transfer printing of the present invention is
  • the metal particles are silver particles; Silver particles, A short-chain amine having 5 or less carbon atoms and a partition coefficient log P of -1.0 to 1.4, A highly polar solvent; A dispersant having an acid value for dispersing the silver fine particles; A silver fine particle dispersion containing Is preferred.
  • the conductive ink for transfer printing of the present invention is In the silver fine particle dispersion, the short chain amine is an alkoxyamine, and further contains a protective dispersant having an acid value. Is preferred.
  • the protective dispersant has an acid value of 5 to 200, and has a functional group derived from phosphoric acid, Is preferred.
  • the conductive ink for transfer printing according to the present invention is a conductive ink for transfer printing that can be suitably used for transfer printing methods including reversal printing methods, and has sufficient conductivity and good adhesion to a substrate.
  • the conductive ink for transfer printing which can bake the electrically conductive film pattern which has this at low temperature is realizable.
  • the conductive ink for transfer printing includes metal particles, a solvent containing ethanol, and 0.1 to 3.0% by mass of a high boiling point solvent having a hydroxyl group. It is characterized by that. Moreover, the solid content which has the metal particle dispersion (in other words metal colloid) particle
  • the dispersibility of the metal colloid particles in the metal colloid liquid can be improved. Therefore, the content of the metal component in the metal colloid liquid can be reduced. Even if it is increased, the colloidal metal particles are less likely to aggregate and good dispersion stability can be maintained.
  • the “dispersibility” as used herein indicates whether or not the dispersion state of the metal particles in the metal colloid liquid is excellent immediately after the metal colloid liquid is prepared (whether it is uniform or not).
  • Dispersion stability indicates whether or not the dispersion state of the metal particles in the metal colloid liquid is maintained after a predetermined time has elapsed after adjusting the metal colloid liquid, It can also be said to be “low sedimentation aggregation”.
  • the “organic component” in the metal colloid particle is an organic substance that substantially constitutes the metal colloid particle together with the metal component.
  • the organic component includes trace organic substances contained in the metal as impurities from the beginning, organic substances adhering to the metal component from trace organic substances mixed in the manufacturing process described later, residual reducing agent that could not be removed in the cleaning process, residual dispersion It does not include organic substances that adhere to trace amounts of metal components such as agents.
  • the “trace amount” is specifically intended to be less than 1% by mass in the metal colloid particles. Since the metal colloid particles in this embodiment contain an organic component, the dispersion stability in the metal colloid liquid is high. Therefore, even if the content of the metal component in the metal colloid liquid is increased, the metal colloid particles are less likely to aggregate, and as a result, good dispersibility is maintained.
  • the “solid content” of the metal colloid liquid in the present embodiment means that after removing the dispersion medium from the metal colloid liquid using silica gel or the like, for example, it is dried at room temperature of 30 ° C. or lower (for example, 25 ° C.) for 24 hours.
  • the solid content that remains is usually contained metal particles, residual organic components, residual reducing agent, and the like.
  • Various methods can be employed as a method of removing the dispersion medium from the metal colloid liquid using silica gel. For example, a metal colloid liquid is applied on a glass substrate and placed in a sealed container containing silica gel. What is necessary is just to remove a dispersion medium by leaving a glass substrate with a coating film for 24 hours or more.
  • the preferable solid content is 1 to 60% by mass.
  • the solid content concentration is 1% by mass or more, the metal content in the conductive ink for transfer printing can be secured, and the conductive efficiency does not decrease.
  • the solid content concentration is 60% by mass or less, the viscosity of the metal colloid liquid does not increase, the handling is easy, it is industrially advantageous, and a flat thin film can be formed.
  • a more preferable solid content is 5 to 40% by mass.
  • the conductive ink for transfer printing of the present invention is characterized by containing 0.1 to 3.0% by mass of a high boiling point solvent having a hydroxyl group.
  • the high boiling point solvent having a hydroxyl group is 1,3-butylene glycol (boiling point: 203 ° C.), 2,4-diethyl-1,5-pentanediol (boiling point: 150 ° C./5 mmHg, 200 ° C. or more at 1 atm) or octane. It is preferably selected from diols (boiling point: 243 ° C.).
  • the “high boiling point solvent” refers to a solvent having a boiling point of 200 ° C. or higher.
  • an ink suitable for transfer printing with a small addition amount can be obtained. can do.
  • the ink applied on the silicone blanket can be semi-dried in a short time, and the printing tact can be shortened.
  • the addition amount of the high boiling point solvent having a hydroxyl group is 0.1 to 3.0% by mass. If the amount is less than 0.1% by mass, the amount is too small to easily form an ink suitable for the transfer printing method. If the amount exceeds 3.0% by mass, the time to reach a semi-dry state suitable for the transfer printing method is reached. It becomes longer and disadvantageous in terms of printing tact.
  • the addition amount of the high boiling point solvent having a hydroxyl group is 0.3 to 2.0% by mass, but it is more sure that the ink is suitable for the transfer printing method, and it is a semi-dry state suitable for the transfer printing method. This is particularly preferable from the viewpoint of shortening the time required to reach the position and being advantageous in terms of printing tact.
  • a highly volatile solvent such as ethanol is added in order to improve the drying property of the ink.
  • the transfer printing conductive ink can be quickly adjusted to a viscosity suitable for printing.
  • the highly volatile solvent include one or more selected from the group of solvents having a boiling point of less than 100 ° C. such as ethanol, methanol, propyl alcohol, isopropyl alcohol, acetone, n-butanol, sec-butanol, tert-butanol and the like. Low boiling solvents can be used.
  • the conductive ink for transfer printing of the present invention preferably contains a fluorine solvent such as hydrofluoroether. Since the fluorine solvent has a low surface tension, it can exhibit good wettability with respect to the silicone blanket, and since the boiling point is relatively low, it can provide good drying properties. Of these, hydrofluoroethers are more preferable than fluorine solvents containing halogen atoms from the viewpoint of the ozone depletion coefficient.
  • hydrofluoroether has an ether bond than hydrofluorocarbons, so it has a high polarity and has the advantage of hardly causing the silicone blanket to swell, and has good compatibility with alcohols such as ethanol, This is more preferable because it has an effect of being excellent in compatibility with metal particles dispersed in alcohol.
  • a fluorine-based surfactant having a fluorine atom may be added for the purpose of improving the wettability with respect to the silicone blanket.
  • the content is preferably 0.01 to 2% by mass.
  • the surface tension is 22 mN / m or less.
  • the surface tension of 22 mN / m or less can be realized by adjusting the component ratio of the conductive ink for transfer printing according to the present invention.
  • the lower limit of the surface tension may be about 13 mN / m.
  • the surface tension referred to in the present invention is obtained by measurement based on the principle of the plate method (Wilhelmy method). For example, the surface tension is measured by a fully automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. can do.
  • the conductive ink for transfer printing of the present embodiment includes silver fine particles, a short-chain amine having a carbon number of 5 or less and a distribution coefficient log P of ⁇ 1.0 to 1.4, a high-polarity solvent, It is preferable to be composed of a silver fine particle dispersion (for example, colloidal) containing a dispersant having an acid value for dispersing the silver fine particles. Details of the silver fine particle dispersion and each component will be described below.
  • the silver fine particle dispersion of the present embodiment contains silver fine particles, a short-chain amine having 5 or less carbon atoms, and a highly polar solvent, and has, for example, a colloidal colloidal liquid form.
  • a colloidal colloidal liquid form for example, silver colloidal particles formed by adhering organic components to the surface of particles composed of silver components, Silver colloidal particles whose surface is coated with an organic component and silver colloidal particles that are configured by uniformly mixing a silver component and an organic component are included.
  • Silver colloidal particles having a particle composed of a silver component as a core and the surface of which is coated with an organic component, or silver colloidal particles formed by uniformly mixing a silver component and an organic component are preferable.
  • a person skilled in the art can appropriately prepare the colloidal silver particles having the above-described form using a well-known technique in this field.
  • the average particle diameter of the silver fine particles contained in the silver fine particle dispersion in the present embodiment is not particularly limited as long as the effects of the present invention are not impaired, but a melting point drop occurs. It is preferable to have such an average particle diameter, for example, it may be 1 to 400 nm. Further, it is preferably 1 to 70 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 400 nm or less, the dispersibility of a silver fine particle does not change easily over time, and it is preferable. In the conductive ink for transfer printing obtained using the silver fine particle dispersion of this embodiment, the average particle diameter (median diameter) of the silver colloid particles (including silver fine particles) is substantially the same as this range. (Can approximate)
  • the particle size of the silver fine particles in the silver fine particle dispersion varies depending on the solid content concentration, and is not necessarily constant, and may not be constant.
  • the silver fine particle dispersion may contain a silver fine particle component having an average particle diameter of more than 400 nm.
  • a silver fine particle component having an average particle diameter of more than 400 nm may be included as long as the component is not significantly impaired.
  • the average particle diameter of the silver fine particles in the silver fine particle dispersion of the present embodiment is based on the dynamic light scattering method (Doppler scattered light analysis).
  • the dynamic light scattering particle diameter manufactured by Horiba, Ltd. It can be represented by a volume-based median diameter (D50) measured by the distribution measuring device LB-550.
  • D50 volume-based median diameter
  • several drops of a metal colloid solution are dropped into 10 mL of ethanol, and are shaken and dispersed by hand to prepare a measurement sample.
  • 3 mL of the measurement sample is put into a cell of a dynamic light scattering particle size distribution measuring device LB-550 manufactured by Horiba, Ltd., and measurement is performed under the following conditions.
  • Measurement condition data read count 100 times Cell holder temperature: 25 ° C
  • Display condition distribution form Standard number of repetitions: 50 times
  • Particle size standard Volume-based refractive index of refractive index: 0.200-3.900i (in the case of silver)
  • Refractive index of dispersion medium 1.36 (when ethanol is the main component)
  • System condition setting strength criteria Dynamic Scattering intensity range upper limit: 10000.00 Scattering intensity range lower limit: 1.00
  • (1-2) Short-chain amine having 5 or less carbon atoms In the silver fine particle dispersion of the present embodiment, a short-chain amine having 5 or less carbon atoms is attached to at least a part of the surface of the silver fine particles. . In addition, on the surface of the silver fine particles, a trace amount of organic matter contained as an impurity from the beginning, a trace amount of organic matter mixed in the manufacturing process described later, a residual reducing agent that could not be removed in the cleaning process, a residual dispersant, etc. A trace amount of organic matter may be attached.
  • the short-chain amine having 5 or less carbon atoms is not particularly limited as long as the distribution coefficient logP is ⁇ 1.0 to 1.4, and may be linear or branched. You may have a chain.
  • Examples of the short chain amine include ethylamine ( ⁇ 0.3) propylamine (0.5), butylamine (1.0), N- (3-methoxypropyl) propane-1,3-diamine ( ⁇ 0.
  • the short chain 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.
  • the said amine may be used independently, respectively and may use 2 or more types together.
  • the boiling point at normal temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.
  • the silver particle dispersion of the present embodiment may contain a carboxylic acid in addition to the short-chain amine having 5 or less carbon atoms 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.
  • the carboxylic acid is localized (attached) on at least a part of the surface of the silver fine particles (that is, covers at least a part of the surface of the silver fine particles) in the silver particle dispersion of the present embodiment, the solvent. And silver fine particles can be made to sufficiently adhere to each other and aggregation of silver fine particles can be prevented (dispersibility is improved).
  • 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 temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.
  • amines and carboxylic acids form amides. Since the amide group also adsorbs moderately on the surface of the silver fine particles, the amide group may adhere to the surface of the silver fine particles.
  • the content of the organic component in the colloid is 0.5 to 50 It is preferable that it is mass%. If the organic component content is 0.5% by mass or more, the storage stability of the resulting silver fine particle dispersion tends to be improved, and if it is 50% by mass or less, the silver fine particle dispersion is obtained by heating. There exists a tendency for the electroconductivity of a sintered body to be good. 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.
  • the silver fine particle dispersion of the present embodiment is a dispersion of silver fine particles in various high polar solvents.
  • High polar solvents include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-butanol, pentanol, hexanol, isoamyl alcohol, furfuryl alcohol, nitromethane, acetonitrile, pyridine, acetone cresol, dimethylformamide, dioxane, ethylene Glycol, glycerin, phenol, p-cresol, propyl acetate, isopropyl acetate, tert-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 3-methyl-1-pentanol, 3- Methyl-2-pentanol, 2-butanol, 1-hexanol, 2-hexanol 2-pentanone, 2-heptanone, 2- (2
  • the silver particle dispersion of the present embodiment further includes a “dispersant having an acid value” added after the synthesis of silver fine particles in order to disperse the silver fine particles.
  • a dispersant having an acid value added after the synthesis of silver fine particles in order to disperse the silver fine particles.
  • the acid value of the dispersant is more preferably from 5 to 200, and it is further preferable that the dispersant has a functional group derived from phosphoric acid.
  • the acid value of the dispersant is 5 or more, adsorption with an acid-base interaction starts to occur on a metal substance that coordinates with the amine and the particle surface is basic. This is because it does not have an adsorption site and adsorbs in a suitable form.
  • the dispersant since the dispersant has a functional group derived from phosphoric acid, phosphorus P interacts with and attracts the metal M through the oxygen O, and is therefore most effective for adsorption with metals and metal compounds. This is because suitable dispersibility can be obtained by the amount of adsorption.
  • Examples of the polymer dispersant having an acid value of 5 to 200 include SOLPERSE-16000, 21000, 41000, 41090, 43000, 44000, 46000, and 54000 in the SOLSPERSE series of Lubrizol.
  • DISPERBYK-102, 110, 111, 170, 190.194N, 2015.2090, 2096 and the like are listed, and in Evonik's TEGO® Dispers series, 610, 610S, 630, 651, 655, 750W, 755W and the like are listed.
  • Disparon series manufactured by Enomoto Kasei Co., Ltd., DA-375, DA-1200 and the like are listed.
  • the content when the dispersant is contained in the silver fine particle dispersion of the present embodiment may be adjusted according to desired properties such as viscosity.
  • desired properties such as viscosity.
  • the content is preferably 0.5 to 20% by mass, and when used as a silver paste, the content of the dispersant is preferably 0.1 to 10% by mass.
  • 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 obtained silver fine particle dispersion is improved.
  • the content is too large, the low-temperature sinterability is lowered.
  • the more preferable content of the polymer dispersant is 0.3 to 10% by mass, and still more preferable content is 0.5 to 8% by mass.
  • the silver fine particle dispersion of this embodiment preferably has a weight loss of 10% by mass or less at 100 to 500 ° C. when thermogravimetric analysis is performed at a rate of temperature increase of 10 ° C./min with respect to the solid content.
  • thermogravimetric analysis is performed at a rate of temperature increase of 10 ° C./min with respect to the solid content.
  • decrease by heating to 500 degreeC can correspond to the quantity of the organic substance in solid content substantially.
  • the weight loss is preferably 20% by mass or less.
  • the content is preferably 0.1% by mass or more.
  • a more preferred weight loss is 0.5 to 15% by mass.
  • the silver fine particle dispersion of this embodiment may further contain a dispersant (protective dispersant) having an acid value as a protective agent added before the synthesis of the silver fine particles.
  • a dispersant protecting dispersant
  • the “protective dispersant” referred to here may be of the same type or different type as the “dispersant having an acid value” added after the synthesis of the silver fine particles.
  • the silver fine particle dispersion of the present embodiment has an appropriate viscosity, adhesiveness, and drying property in accordance with the purpose of use within a range not impairing the effects of the present invention.
  • an oligomer component that plays a role as a binder for example, an oligomer component that plays a role as a binder, a resin component, an organic solvent (a part of the solid content may be dissolved or dispersed), a surfactant, a thickening agent.
  • 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 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. , Hydroxypropylcellulose, cellulose derivatives of hydroxypropylmethylcellulose, polysaccharides such as xanthan gum or guar gum, etc., and 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.
  • Hydroxypropylcellulose cellulose derivatives of hydroxypropylmethylcellulose
  • polysaccharides such as
  • 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.
  • an anionic surfactant for example, alkylbenzene sulfonic acid Salt, quaternary ammonium salt and the like.
  • fluorine-based surfactants and silicone-based surfactants are preferred because an effect can be obtained with a small amount of addition. If the content of the surfactant is too small, the effect cannot be obtained. If the content is too large, the remaining amount of impurities in the coating becomes an impurity, so that the conductivity may be hindered.
  • a preferable surfactant content is 0.01 to 5 parts by mass with respect to 100 parts by mass of the dispersion medium of the silver fine particle dispersion.
  • the silver fine particles in the present embodiment are silver fine particles in which an alkoxyamine having a distribution coefficient logP of ⁇ 1.0 to 1.4 and a carbon number of 5 or less is attached to at least a part of the surface.
  • an alkoxyamine having a partition coefficient logP of ⁇ 1.0 to 1.4 and having 5 or less carbon atoms is attached to at least a part of the surface of the silver fine particles.
  • the silver fine particles can be used for various solvents (particularly highly polar solvents). Excellent dispersibility and low-temperature sinterability can be imparted.
  • the solvent various solvents can be used as long as the effects of the present invention are not impaired, and a solvent having an SP value (solubility parameter) of 7.0 to 15.0 can be used.
  • SP value solubility parameter
  • the phase is combined with the short-chain amine having 5 or less carbon atoms. It is preferable to use an alcohol having 1 to 6 carbon atoms because of good solubility.
  • Examples of the solvent having an SP value (solubility parameter) of 7.0 to 15.0 include hexane (7.2), triethylamine (7.3), ethyl ether (7.7), and n-octane (7. 8), cyclohexane (8.3), n-amyl acetate (8.3), isobutyl acetate (8.3), methyl isopropyl ketone (8.4), amyl benzene (8.5) butyl acetate (8.5) ), Carbon tetrachloride (8.6), ethylbenzene (8.7), p-xylene (8.8), toluene (8.9), methyl propyl ketone (8.9) ethyl acetate (8.9), Tetrahydrofuran (9.2), methyl ethyl ketone (9.3), chloroform (9.4), acetone (9.8), dioxane (10.1), pyridine (10.8), is
  • the viscosity of the silver fine particle dispersion of this embodiment is preferably in the viscosity range of 1 to 100 cps, and more preferably in the viscosity range of 1 to 20 cps. By setting it as the said viscosity range, a silver fine particle dispersion can be apply
  • a general-purpose coating method can be used as the coating method, and examples include an applicator method, a bar coater method, a capillary coater method, and a spin coating method.
  • the viscosity of the silver fine particle dispersion of the present embodiment can be adjusted by adjusting the solid content concentration, adjusting the blending ratio of each component, adding a thickener, and the like.
  • the viscosity can be measured with a vibration viscometer (for example, VM-100A-L manufactured by CBC Corporation). The measurement is performed by immersing the liquid in the vibrator, and the measurement temperature may be normal temperature (20 to 25 ° C.).
  • the silver fine particle dispersion of the present embodiment includes a step of generating silver fine particles, and a step of adding and mixing a dispersant having an acid value for dispersing the silver fine particles to the silver fine particles.
  • a first pre-process for preparing a mixture of a silver compound that can be decomposed by reduction to produce metallic silver and a short-chain amine having a partition coefficient log P of ⁇ 1.0 to 1.4 It is preferable to include a second pre-process of reducing the silver compound in the mixed solution to generate silver fine particles having a short-chain amine having 5 or less carbon atoms attached to at least a part of the surface.
  • the first pre-process it is preferable to add 2 mol or more of short chain amine to 1 mol of metallic silver.
  • an appropriate amount of the short chain amine can be attached to the surface of the silver fine particles produced by the reduction, and various solvents (particularly, Excellent dispersibility and low-temperature sinterability with respect to a highly polar solvent) can be imparted.
  • 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, heating time, etc.) in the second pre-process.
  • the thickness is 1 to 200 nm.
  • particles of micrometer size 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 salts such as silver nitrate, silver sulfate, silver chloride, 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 a short-chain amine as a protective dispersant or a protective dispersant having an acid value to the metal salt solution, and then gradually dropping a solution in which the reducing agent is dissolved. .
  • the dispersant in addition to the silver fine particles, a metal ion counter ion, a reducing agent residue, there is a dispersant, and the concentration of the electrolyte and the organic matter in 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 method 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 excess residues and removing the organic solvent by such washing, metal particles coated with the “short-chain amine or the dispersant having an acid value” of the present embodiment can be obtained.
  • a solvent for precipitating silver fine particles for example, water, methanol, Methanol / water mixed solvent, etc.
  • the silver fine particle dispersion includes the silver fine particles coated with the short-chain amine obtained above and a protective dispersant having an acid value, and the dispersion medium described in the present embodiment. And are mixed.
  • the mixing method of the metal particles coated with the “short-chain amine or the protective dispersant having an acid value” and the dispersion medium is not particularly limited, and may be performed by a conventionally known method using a stirrer or a stirrer. Can do. An ultrasonic homogenizer with an appropriate output may be applied by stirring with a spatula or the like.
  • the production method is not particularly limited.
  • the silver fine particle dispersion when producing a silver fine particle dispersion composed of silver and other metals, the silver fine particle dispersion is coated with the organic substance.
  • a dispersion containing silver fine particles and a dispersion containing other metal particles may be produced separately and then mixed, or a silver ion solution and other metal ion solution may be mixed. Thereafter, reduction may be performed.
  • Silver fine particles may be produced by the second step of producing silver fine particles in which a short-chain amine having 5 or less carbon atoms is attached to at least a part of the surface by reducing the silver compound.
  • atomic silver produced by heating a complex compound generated from a metal compound such as silver oxalate containing silver and a short-chain amine and decomposing the metal compound such as oxalate ion contained in the complex compound
  • a metal compound such as silver oxalate containing silver and a short-chain amine
  • decomposing the metal compound such as oxalate ion contained in the complex compound
  • the metal amine complex decomposition method for producing metal particles coated with amine by thermally decomposing a complex compound of a metal compound in the presence of amine decomposition of the metal amine complex which is a single kind of molecule is performed. Since the atomic metal is generated by the reaction, it is possible to generate the atomic metal uniformly in the reaction system, and the reaction is configured as compared with the case where the metal atom is generated by the 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 metal powder is produced on an industrial scale.
  • a short chain amine molecule is coordinated to the metal atom to be generated, and the movement of the metal atom when aggregation occurs due to the action of the short chain amine molecule coordinated to the metal atom. Is assumed to be controlled. As a result, according to the metal amine complex decomposition method, it is possible to produce metal particles that are very fine and have a narrow particle size distribution.
  • short-chain amine molecules also form a relatively weak coordination bond on the surface of the metal fine particles to be produced, and these form a dense protective film on the surface of the metal particles. It is possible to produce coated metal particles having a clean surface with excellent surface resistance. In addition, since the short-chain amine molecules forming the coating can be easily detached by heating or the like, it is possible to produce metal particles that can be sintered at a very low temperature.
  • the number of carbon atoms is 5 or less with respect to the dispersant having an acid value constituting the coating of the coated silver particles.
  • the conductive ink applying step for applying the conductive ink for transfer printing to the base material.
  • a conductive film pattern forming step in which the conductive ink for transfer printing applied to the substrate is baked at a temperature of 200 ° C. or lower (preferably less than 180 ° C., more preferably 150 ° C. or lower) to form a conductive film pattern.
  • the inventor used the conductive ink for transfer printing according to the present embodiment described above as the conductive ink in the conductive ink application process for transfer printing. It has been found that even when the conductive ink applied to the substrate is baked at a temperature of 200 ° C. or less, a conductive film pattern having excellent conductivity can be obtained with certainty.
  • a conductive ink application surface is formed by applying conductive ink for transfer printing on a blanket.
  • a silicone blanket made of silicone is preferable.
  • the portion of the conductive ink that contacts the relief plate is removed from the blanket.
  • the conductive ink has an appropriate cohesiveness, the conductive ink is surely peeled off from the blanket and adhered to the relief plate without structural destruction, and undesirable residue on the blanket is prevented. It is suppressed.
  • the conductive ink remaining on the blanket forms a conductive ink pattern corresponding to the relief pattern on the blanket.
  • the substrate that can be used in the present embodiment is not particularly limited as long as it has at least one main surface on which a conductive ink can be applied and fired by heating to mount a conductive film pattern. Although it is not, it is preferable that it is a base material excellent in heat resistance.
  • the conductive ink for transfer printing of this embodiment has a conductive film pattern that has sufficient conductivity even when heated and baked at a lower temperature than conventional conductive inks. Since it can be obtained, it is possible to use a substrate 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 is baked by heating to a temperature of 200 ° C. or less (preferably less than 180 ° C., more preferably 150 ° C. or less), and the conductive film pattern (conductive film pattern) of this embodiment. Substrate) can be obtained.
  • the method for performing the baking is not particularly limited.
  • the temperature of the conductive ink applied or drawn on the substrate using a conventionally known gear oven or the like is 200 ° C. or less (preferably less than 180 ° C., More preferably, the conductive film pattern can be formed by baking to 150 ° C. or lower.
  • the lower limit of the firing temperature is not necessarily limited, and is a temperature at which a conductive film pattern can be formed on a substrate, and a temperature at which the organic components and the like can be removed by evaporation or decomposition within a range that does not impair 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 film pattern exhibiting high conductivity can be formed even by a low-temperature heat treatment at about 120 ° C. Therefore, the conductive film pattern is also formed on a relatively heat-sensitive substrate. Can be formed. Moreover, baking time is not specifically limited, A conductive film pattern can be formed on a base material according to baking temperature.
  • the substrate in order to further improve the adhesion between the substrate and the conductive film pattern, the substrate may be subjected to a surface treatment.
  • a surface treatment method include a method of performing a dry treatment such as a corona treatment, a plasma treatment, a UV treatment, and an electron beam treatment, and a method of previously providing a primer layer and a conductive ink receiving layer on a substrate.
  • the conductive film pattern (substrate with conductive film pattern) of this embodiment can be obtained.
  • the conductive film 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 film pattern having sufficient conductivity can be obtained even when the thickness is about 0.1 to 5 ⁇ m.
  • the volume resistance value of the electrically conductive film pattern of this embodiment is 15 microhm * cm or less.
  • the thickness t of the conductive film pattern of the present embodiment can be obtained using, for example, the following formula (the thickness t of the conductive film pattern is measured with a laser microscope (for example, a laser microscope VK-9510 manufactured by Keyence). It is also possible to do this.)
  • Formula: t m / (d ⁇ M ⁇ w)
  • m conductive film pattern weight (the weight of the conductive film pattern formed on the slide glass is measured with an electronic balance)
  • d Conductive film pattern density (g / cm 3 ) (10.5 g / cm 3 in the case of silver)
  • M conductive film pattern length (cm) (the length of the conductive film pattern formed on the slide glass is measured on a scale equivalent to JIS class 1)
  • w Conductive film pattern width (cm) (The width of the conductive film pattern formed on the slide glass is measured on a scale equivalent to JIS class 1)
  • the conductive ink for transfer printing of the present invention and a method for producing a conductive film pattern (substrate with a conductive film pattern) using the conductive ink will be further described with reference to Examples and Comparative Examples.
  • the present invention is not limited to these examples.
  • ⁇ Preparation Example 1 8.9 g of 3-methoxypropylamine (Wako Pure Chemical Industries, Ltd., first grade reagent, carbon number: 4, log P: -0.5) and 0.3 g of DISPERBYK-111, a polymer dispersant, are mixed. Then, the mixture was thoroughly stirred with a magnetic stirrer to produce an amine mixture (molar ratio of added amine was 10 with respect to silver). Next, 3.0 g of silver oxalate was added while stirring. After the addition of silver oxalate, by continuing stirring at room temperature, the silver oxalate was changed to a viscous white substance, and it was visually confirmed that the change was apparently observed. Finished (first pre-process).
  • the resulting mixture was transferred to an oil bath and heated and stirred at 120 ° C.
  • the reaction with the generation of carbon dioxide started immediately after the start of stirring, 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 ( Second pre-process).
  • 10 mL of a mixed solvent of methanol / water was added and stirred, and then silver fine particles were precipitated and separated by centrifugation.
  • ⁇ Preparation Example 2 >> 8.9 g of 3-methoxypropylamine (Wako Pure Chemical Industries, Ltd., first grade reagent, carbon number: 4, log P: -0.5) and 0.3 g of DISPERBYK-102, a polymer dispersant, are mixed. Then, the mixture was thoroughly stirred with a magnetic stirrer to produce an amine mixture (molar ratio of added amine was 5 with respect to silver). Next, 3.0 g of silver oxalate was added while stirring. After the addition of silver oxalate, by continuing stirring at room temperature, the silver oxalate was changed to a viscous white substance, and it was visually confirmed that the change was apparently observed. Finished (first pre-process).
  • the resulting mixture was transferred to an oil bath and heated and stirred at 120 ° C.
  • the reaction with the generation of carbon dioxide started immediately after the start of stirring, 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 ( Second pre-process).
  • 10 mL of a mixed solvent of methanol / water was added and stirred, and then silver fine particles were precipitated and separated by centrifugation.
  • 10 mL of a mixed solvent of methanol / water was added and stirred again, and then the silver fine particles were settled and separated by centrifugation.
  • a silver fine particle dispersion B having a solid content concentration of 48% by mass was obtained.
  • Examples and Comparative Examples >> Using the silver fine particle dispersion A or B obtained as described above, it was mixed with the other components shown in Table 1, and Examples 1 to 7 of the conductive inks 1 to 7 for transfer printing and Comparative Examples 1 to 3 were used. Conductive inks 1 to 3 for comparative transfer printing were prepared. The unit of the amount of the component in Table 1 was “mass%”. In addition, the following evaluation tests were performed on the above-described silver fine particle dispersions A and B, the conductive inks 1 to 7 for the transfer printing, and the conductive inks 1 to 3 for the comparative transfer printing. The results are shown in Table 1.
  • Conductive ink wettability evaluation Conductive transfer printing conductive inks 1 to 7 obtained in Examples 1 to 7 and Comparative transfer printing conductive inks 1 to 3 obtained in Comparative Examples 1 to 3 was applied on a silicone blanket with a bar coater (No. 7), and the wettability of the conductive ink for transfer printing to the blanket was visually evaluated. When the wettability was good, it was evaluated as “ ⁇ ”, and when it was poor, it was evaluated as “x”. (5) Evaluation of printing shape (thin line drawing property) A glass relief was pressed on a blanket coated with conductive ink for transfer printing, and a non-image part (unnecessary part) was transferred and removed.
  • the pattern was transferred to the base material by pressing the base material (PEN: polyethylene naphthalate) against the blanket material.
  • the printed shape was evaluated by visually observing the obtained pattern shape. Evaluate as “ ⁇ ” when the printed shape is good, “ ⁇ ” when it is acceptable, and “x” when it is defective.
  • the pattern was a thin line, and the line width was 10, 20, 30, 50, 100 ⁇ m and the length was 10 mm.
  • (6) Evaluation of transferability Transferability was evaluated by visually evaluating the printed shape formed in (5) above and the conductive ink remaining on the blanket. “ ⁇ ” if the printed shape is good and almost not left on the blanket, “ ⁇ ” if it is acceptable, or “x” if the printed shape is bad or clearly left on the blanket .
  • the conductive ink for transfer printing of the present invention is excellent in dispersibility, wettability, printability and conductivity.
  • Examples 3 and 4 using the silver fine particle dispersion B are particularly preferable because they are excellent in continuous printability.
  • Comparative Examples 1 and 2 it can be seen from Comparative Examples 1 and 2 that the conductive ink containing no specific high boiling point solvent is inferior in transferability.
  • Comparative Example 3 when the content of the high boiling point solvent is excessive, drying is slow and transferability is poor.
  • Comparative Example 2 that even when only the fluorine solvent is included, the wettability can be ensured but the transferability is poor.

Abstract

Provided is a conductive ink for transfer printing with which it is possible to fire at low temperature a conductive film pattern having adequate conductivity and excellent adhesiveness with a substrate. A conductive ink for transfer printing, characterized by containing metal particles, a solvent containing ethanol, and 0.1-3.0 mass% of a high-boiling-point solvent that has hydroxyl groups.

Description

導電性インクConductive ink
　本発明は、半導体集積回路等の配線や電極パターンを形成するために用いる導電性インクであって、有機薄膜トランジスタ基板に対する配線や電極パターンの形成が可能な導電性インクに関する。より詳しくは、本発明は、反転印刷法等を含む転写印刷法を用いた配線や電極パターンの形成に好適に用いることができる導電性インクに関する。 The present invention relates to a conductive ink used for forming a wiring or an electrode pattern of a semiconductor integrated circuit or the like and capable of forming a wiring or an electrode pattern on an organic thin film transistor substrate. More specifically, the present invention relates to a conductive ink that can be suitably used for forming a wiring or an electrode pattern using a transfer printing method including a reverse printing method.
　従来から、基板の全面にスパッタや蒸着等で金属薄膜を形成させた後、フォトリソグラフィー法によって不要な部分をエッチングして必要な導電膜パターンを形成させる方法が知られている。しかしながら、当該方法は工程が煩雑であることに加え、高価な真空装置を用いる必要がある。 Conventionally, a method is known in which a metal thin film is formed on the entire surface of a substrate by sputtering or vapor deposition, and then an unnecessary portion is etched by photolithography to form a necessary conductive film pattern. However, this method requires complicated vacuum processes and an expensive vacuum apparatus.
　このため、より簡便かつ安価な導電膜パターンの形成方法が求められており、近年、凸版印刷法、凹版印刷法、スクリーン印刷法、インクジェット印刷法等の印刷法を用いた方法が提案されている。更に、より高精細なパターンが形成できる印刷手法として、反転印刷法やマイクロコンタクト印刷法等を用いた方法が提案されており、これらの印刷法に適した導電性インク、絶縁性インク、及び抵抗インク等の各種インクが開発されている。 For this reason, a simpler and less expensive method for forming a conductive film pattern has been demanded. In recent years, methods using printing methods such as letterpress printing, intaglio printing, screen printing, and ink jet printing have been proposed. . Furthermore, as a printing method capable of forming a higher-definition pattern, a method using a reverse printing method, a microcontact printing method, or the like has been proposed, and conductive ink, insulating ink, and resistance suitable for these printing methods are proposed. Various inks such as ink have been developed.
　特許文献１においては、凸版反転印刷法による微細な導電膜パターンを形成するための導電性インクが提案されており、具体的には、凸版反転印刷法により導電膜パターンを形成するための実質的にバインダ成分を含まない導電性インクであって、体積平均粒径（Ｍｖ）が１０～７００ｎｍの導電性粒子、離型剤、表面エネルギー調整剤、溶剤成分を必須成分とし、溶剤成分が２５℃での表面エネルギーが２７ｍＮ／ｍ以上の溶剤と、大気圧下での沸点が１２０℃以下の揮発性の溶剤との混合物であり、２５℃におけるインクの表面エネルギーが１０～２１ｍＮ／ｍであることを特徴とする導電性インクが開示されている。 In Patent Document 1, a conductive ink for forming a fine conductive film pattern by a letterpress reverse printing method has been proposed. Specifically, a substantial effect for forming a conductive film pattern by a letterpress reverse printing method is proposed. Is a conductive ink which does not contain a binder component, and has a volume average particle size (Mv) of 10 to 700 nm, a conductive particle, a release agent, a surface energy adjusting agent, a solvent component as essential components, and a solvent component at 25 ° C. A mixture of a solvent having a surface energy of 27 mN / m or more and a volatile solvent having a boiling point of 120 ° C. or less under atmospheric pressure, and the surface energy of the ink at 25 ° C. is 10 to 21 mN / m An electrically conductive ink is disclosed.
　上記特許文献１に記載の導電性インクを用いることで、凸版反転印刷法により微細な導電膜パターンを転写不良が無く安定的に形成することができ、例えば導電性粒子として銀を用いた場合には形成した微細パターンを２００℃以下の低温で焼成することで、比抵抗が１０-5Ω・ｃｍオーダー以下の優れた導電性を付与することができることに加え、転写性に優れるので、全転写にて微細パターンの形成が可能となる、としている。 By using the conductive ink described in Patent Document 1, a fine conductive film pattern can be stably formed without a transfer defect by a letterpress reverse printing method. For example, when silver is used as conductive particles In addition to providing excellent conductivity with a specific resistance of the order of 10 −5 Ω · cm or less by firing the formed fine pattern at a low temperature of 200 ° C. or less, it is excellent in transferability. It becomes possible to form a fine pattern.
　また、特許文献２においては、「最大泡圧法によって求められる２５℃での動的表面張力を、気泡の発生周期を０．０５Ｈｚに設定して測定したとき１６ｍＮ／ｍ以上、２３ｍＮ／ｍ以下で、かつ前記発生周期を１０．０Ｈｚに設定して測定したとき２０ｍＮ／ｍ以上、２７ｍＮ／ｍ以下としたインキ」が開示されている。 Further, in Patent Document 2, “when the dynamic surface tension at 25 ° C. determined by the maximum bubble pressure method is measured by setting the bubble generation period to 0.05 Hz, it is 16 mN / m or more and 23 mN / m or less. In addition, an ink having 20 mN / m or more and 27 mN / m or less when measured with the generation period set to 10.0 Hz is disclosed.
　このインキは、動的表面張力を適切な範囲に調整することによって、シリコーンブランケットの表面に対して適度の濡れ性と離型性とを兼ね備え、基板等の被印刷体の表面にムラや欠陥の無い厚みが均一なインキパターンが得られる反転印刷用のインキである。 This ink has appropriate wettability and releasability on the surface of the silicone blanket by adjusting the dynamic surface tension to an appropriate range. This is an ink for reversal printing in which an ink pattern having a uniform thickness is obtained.
国際公開第ＷＯ２００８／１１１４８４号公報International Publication No. WO2008 / 111484 特開２０１１－２５２０７２号公報JP 2011-252072 A
　しかしながら、上記特許文献１に記載の導電性インクを用いることで微細なパターンを形成させることはできるが、実質的にバインダを含まないために、基板上に形成された導電膜パターンの密着性が乏しい場合が存在する。更に、導電性を発現するためには１８０℃以上の焼成温度が必要であり、耐熱性に劣る安価な基材を用いることができないという問題がある。 However, a fine pattern can be formed by using the conductive ink described in Patent Document 1, but since the binder is substantially not included, the adhesion of the conductive film pattern formed on the substrate is low. There are scarce cases. Furthermore, in order to develop conductivity, a baking temperature of 180 ° C. or higher is necessary, and there is a problem that an inexpensive base material having poor heat resistance cannot be used.
　また、上記特許文献２で開示されているインキは主として液晶ディスプレイを構成するカラーフィルタに好適なインキであってそのまま反転印刷法等の転写印刷法に好適な導電性インクに使用できず、またバインダを溶解させる溶剤を比較的多量に含むため、シリコーンブランケット表面に塗工後比較的長い時間乾燥させる必要があり、印刷タクトが比較的長いという点で問題があった。 The ink disclosed in Patent Document 2 is mainly suitable for a color filter constituting a liquid crystal display and cannot be used as it is for a conductive ink suitable for a transfer printing method such as a reverse printing method. Since a relatively large amount of the solvent for dissolving the resin is contained, it is necessary to dry the surface of the silicone blanket for a relatively long time after coating, and there is a problem in that the printing tact is relatively long.
　そこで、本発明の目的は、上記従来技術の有する課題に鑑みてなされたものであり、反転印刷法等を含む転写印刷法に好適に用いることができる転写印刷用導電性インクであって、十分な導電性及び基板との良好な密着性を有する導電膜パターンを低温で焼成することができる転写印刷用導電性インクを提供することにある。 Accordingly, an object of the present invention has been made in view of the above-described problems of the prior art, and is a conductive ink for transfer printing that can be suitably used for a transfer printing method including a reverse printing method. An object of the present invention is to provide a conductive ink for transfer printing, which can fire a conductive film pattern having good conductivity and good adhesion to a substrate at a low temperature.
　本発明者は、上記目的を達成すべく鋭意研究を重ねた結果、反転印刷法等を含む転写印刷法に好適に用いることができる転写印刷用導電性インクであって、十分な導電性及び基板との良好な密着性を有する導電膜パターンを低温で焼成することができる転写印刷用導電性インクを得るためには、適当な量の金属粒子及び特定の水酸基を有する高沸点溶剤を含むことが、上記目的を達成する上で極めて有効であることを見出し、本発明に到達した。 As a result of intensive studies to achieve the above object, the present inventor is a conductive ink for transfer printing that can be suitably used for transfer printing methods including reversal printing methods, etc., and has sufficient conductivity and substrate. In order to obtain a conductive ink for transfer printing that can be baked at a low temperature, a conductive film pattern having good adhesiveness with a suitable amount of metal particles and a high boiling point solvent having a specific hydroxyl group may be included. The inventors have found that the present invention is extremely effective in achieving the above-described object, and have reached the present invention.
　即ち、本発明は、
　金属粒子と、
　エタノールを含む溶媒と、
　水酸基を有する高沸点溶剤０．１～３．０質量％と、を含むこと、
　を特徴とする転写印刷用導電性インク
を提供する。 That is, the present invention
Metal particles,
A solvent comprising ethanol;
Containing 0.1 to 3.0% by mass of a high-boiling solvent having a hydroxyl group,
A conductive ink for transfer printing is provided.
　本発明における「転写印刷法」のなかで、その代表的な「反転印刷法」について説明する。「反転印刷法」は、シリコーン樹脂等のブランケット上にインクを塗布してインク塗布面を形成し、当該インク塗布面に非画像部を除去するための凸版を押圧して当該凸版に接触する部分のインクをブランケット上から除去した後、当該ブランケット上に残ったインクを被印刷体に転写する印刷方法である。 In the “transfer printing method” of the present invention, a typical “reverse printing method” will be described. “Reversal printing method” is a portion in which ink is applied onto a blanket such as a silicone resin to form an ink application surface, and a relief plate for removing a non-image part is pressed on the ink application surface to contact the relief plate After the ink is removed from the blanket, the ink remaining on the blanket is transferred to a printing medium.
　本発明の転写印刷用導電性インクにおいては、前記高沸点溶剤が、１，３－ブチレングリコール、２，４－ジエチル－１，５－ペンタンジオール又はオクタンジオールを含むこと、がより好ましい。 In the conductive ink for transfer printing of the present invention, it is more preferable that the high boiling point solvent contains 1,3-butylene glycol, 2,4-diethyl-1,5-pentanediol or octanediol.
　また、本発明の転写印刷用導電性インクは、更にハイドロフルオロエーテルを含むこと、が好ましい。 Moreover, it is preferable that the conductive ink for transfer printing of the present invention further contains hydrofluoroether.
　また、本発明の転写印刷用導電性インクは、
　前記金属粒子が銀微粒子であり、
　銀微粒子と、
炭素数が５以下であり分配係数ｌｏｇＰが－１．０～１．４である短鎖アミンと、
　高極性溶媒と、
　前記銀微粒子を分散させるための酸価を有する分散剤と、
を含む銀微粒子分散体を含むこと、
　が好ましい。 The conductive ink for transfer printing of the present invention is
The metal particles are silver particles;
Silver particles,
A short-chain amine having 5 or less carbon atoms and a partition coefficient log P of -1.0 to 1.4,
A highly polar solvent;
A dispersant having an acid value for dispersing the silver fine particles;
A silver fine particle dispersion containing
Is preferred.
　更に、本発明の転写印刷用導電性インクは、
　前記銀微粒子分散体において、前記短鎖アミンがアルコキシアミンであり、更に、酸価を有する保護分散剤を含むこと、
　が好ましい。 Furthermore, the conductive ink for transfer printing of the present invention is
In the silver fine particle dispersion, the short chain amine is an alkoxyamine, and further contains a protective dispersant having an acid value.
Is preferred.
　更に、本発明の転写印刷用導電性インクにおいては、
　前記保護分散剤の酸価が５～２００であり、リン酸由来の官能基を有すること、
　が好ましい。 Furthermore, in the conductive ink for transfer printing of the present invention,
The protective dispersant has an acid value of 5 to 200, and has a functional group derived from phosphoric acid,
Is preferred.
　本発明の転写印刷用導電性インクによれば、反転印刷法を含む転写印刷法に好適に用いることができる転写印刷用導電性インクであって、十分な導電性及び基板との良好な密着性を有する導電膜パターンを低温で焼成することができる転写印刷用導電性インクを実現することができる。 The conductive ink for transfer printing according to the present invention is a conductive ink for transfer printing that can be suitably used for transfer printing methods including reversal printing methods, and has sufficient conductivity and good adhesion to a substrate. The conductive ink for transfer printing which can bake the electrically conductive film pattern which has this at low temperature is realizable.
　以下、（１）本発明の転写印刷用導電性インクの好適な一実施形態、（２）本発明の転写印刷用導電性インクの製造方法の好適な一実施形態、（３）本発明の転写印刷用導電性インクを用いた導電膜パターン及びその製造方法について詳細に説明する。なお、以下の説明では重複する説明は省略することがある。 Hereinafter, (1) one preferred embodiment of the conductive ink for transfer printing of the present invention, (2) one preferred embodiment of the method for producing the conductive ink for transfer printing of the present invention, and (3) the transfer of the present invention. A conductive film pattern using a conductive ink for printing and a manufacturing method thereof will be described in detail. In the following description, overlapping description may be omitted.
（１）転写印刷用導電性インク
　本実施形態の転写印刷用導電性インクは、金属粒子と、エタノールを含む溶媒と、水酸基を有する高沸点溶剤０．１～３．０質量％と、を含むことを特徴とする。また、金属粒子と有機成分とからなる金属粒子分散体（換言すれば金属コロイド）粒子を主成分とする固形分と、これら固形分を分散する分散媒とを含むものである。ただし、上記コロイド液において、「分散媒」は上記固形分の一部を溶解していても構わない。 (1) Conductive ink for transfer printing The conductive ink for transfer printing according to this embodiment includes metal particles, a solvent containing ethanol, and 0.1 to 3.0% by mass of a high boiling point solvent having a hydroxyl group. It is characterized by that. Moreover, the solid content which has the metal particle dispersion (in other words metal colloid) particle | grains which consist of a metal particle and an organic component as a main component, and the dispersion medium which disperse | distributes these solid content are included. However, in the colloid liquid, the “dispersion medium” may dissolve a part of the solid content.
　このような金属コロイド液によれば、有機成分を含んでいるため、金属コロイド液中での金属コロイド粒子の分散性を向上させることができ、したがって、金属コロイド液中の金属成分の含有量を増やしても金属コロイド粒子が凝集しにくく、良好な分散安定性を保つことができる。なお、ここでいう「分散性」とは、金属コロイド液を調製した直後において、当該金属コロイド液中での金属粒子の分散状態が優れているか否か（均一か否か）を示すものであり、「分散安定性」とは、金属コロイド液を調整して所定の時間を経過した後において、当該金属コロイド液中での金属粒子の分散状態が維持されているか否かを示すものであり、「低沈降凝集性」ともいえる。 According to such a metal colloid liquid, since it contains an organic component, the dispersibility of the metal colloid particles in the metal colloid liquid can be improved. Therefore, the content of the metal component in the metal colloid liquid can be reduced. Even if it is increased, the colloidal metal particles are less likely to aggregate and good dispersion stability can be maintained. The “dispersibility” as used herein indicates whether or not the dispersion state of the metal particles in the metal colloid liquid is excellent immediately after the metal colloid liquid is prepared (whether it is uniform or not). , "Dispersion stability" indicates whether or not the dispersion state of the metal particles in the metal colloid liquid is maintained after a predetermined time has elapsed after adjusting the metal colloid liquid, It can also be said to be “low sedimentation aggregation”.
　ここで、上記の金属コロイド液において、金属コロイド粒子中の「有機成分」は、上記金属成分とともに実質的に金属コロイド粒子を構成する有機物のことである。当該有機成分には、金属中に最初から不純物として含まれる微量有機物、後述する製造過程で混入した微量の有機物が金属成分に付着した有機物、洗浄過程で除去しきれなかった残留還元剤、残留分散剤等のように、金属成分に微量付着した有機物等は含まれない。なお、上記「微量」とは、具体的には、金属コロイド粒子中１質量％未満が意図される。
　本実施形態における金属コロイド粒子は、有機成分を含んでいるため、金属コロイド液中での分散安定性が高い。そのため、金属コロイド液中の金属成分の含有量を増大させても金属コロイド粒子が凝集しにくく、その結果、良好な分散性が保たれる。 Here, in the metal colloid liquid, the “organic component” in the metal colloid particle is an organic substance that substantially constitutes the metal colloid particle together with the metal component. The organic component includes trace organic substances contained in the metal as impurities from the beginning, organic substances adhering to the metal component from trace organic substances mixed in the manufacturing process described later, residual reducing agent that could not be removed in the cleaning process, residual dispersion It does not include organic substances that adhere to trace amounts of metal components such as agents. The “trace amount” is specifically intended to be less than 1% by mass in the metal colloid particles.
Since the metal colloid particles in this embodiment contain an organic component, the dispersion stability in the metal colloid liquid is high. Therefore, even if the content of the metal component in the metal colloid liquid is increased, the metal colloid particles are less likely to aggregate, and as a result, good dispersibility is maintained.
　また、本実施形態における金属コロイド液の「固形分」とは、シリカゲル等を用いて金属コロイド液から分散媒を取り除いた後、例えば、３０℃以下の常温（例えば２５℃）で２４時間乾燥させたときに残存する固形分のことをいい、通常は、金属粒子、残存有機成分及び残留還元剤等を含むものである。なお、シリカゲルを用いて金属コロイド液から分散媒を取り除く方法としては、種々の方法を採用することが可能であるが、例えばガラス基板上に金属コロイド液を塗布し、シリカゲルを入れた密閉容器に塗膜付ガラス基板を２４時間以上放置することにより分散媒を取り除けばよい。 In addition, the “solid content” of the metal colloid liquid in the present embodiment means that after removing the dispersion medium from the metal colloid liquid using silica gel or the like, for example, it is dried at room temperature of 30 ° C. or lower (for example, 25 ° C.) for 24 hours. In general, the solid content that remains is usually contained metal particles, residual organic components, residual reducing agent, and the like. Various methods can be employed as a method of removing the dispersion medium from the metal colloid liquid using silica gel. For example, a metal colloid liquid is applied on a glass substrate and placed in a sealed container containing silica gel. What is necessary is just to remove a dispersion medium by leaving a glass substrate with a coating film for 24 hours or more.
　本実施形態の金属コロイド液において、好ましい固形分の濃度は１～６０質量％である。固形分の濃度が１質量％以上であれば、転写印刷用導電性インクにおける金属の含有量を確保することができ、導電効率が低くならない。また、固形分の濃度が６０質量％以下であれば、金属コロイド液の粘度が増加せず取り扱いが容易で、工業的に有利であり、平坦な薄膜を形成することができる。より好ましい固形分の濃度は５～４０質量％である。 In the metal colloid liquid of the present embodiment, the preferable solid content is 1 to 60% by mass. When the solid content concentration is 1% by mass or more, the metal content in the conductive ink for transfer printing can be secured, and the conductive efficiency does not decrease. In addition, when the solid content concentration is 60% by mass or less, the viscosity of the metal colloid liquid does not increase, the handling is easy, it is industrially advantageous, and a flat thin film can be formed. A more preferable solid content is 5 to 40% by mass.
　本発明の転写印刷用導電性インクは、水酸基を有する高沸点溶剤を０．１～３．０質量％含むことを特徴とする。水酸基を有する高沸点溶剤は、１，３－ブチレングリコール（沸点：２０３℃）、２，４－ジエチル－１，５－ペンタンジオール（沸点：１５０℃／５ｍｍＨｇ、１気圧では２００℃以上）又はオクタンジオール（沸点：２４３℃）から選択されるのが好ましい。 The conductive ink for transfer printing of the present invention is characterized by containing 0.1 to 3.0% by mass of a high boiling point solvent having a hydroxyl group. The high boiling point solvent having a hydroxyl group is 1,3-butylene glycol (boiling point: 203 ° C.), 2,4-diethyl-1,5-pentanediol (boiling point: 150 ° C./5 mmHg, 200 ° C. or more at 1 atm) or octane. It is preferably selected from diols (boiling point: 243 ° C.).
　本発明においていう「高沸点溶剤」とは、２００℃以上の沸点を有する溶剤のことをいう。また、水酸基を有することによって水に対して適度な親和性を有し、空気中の水分を吸収乃至は吸着等して保湿する傾向があるため、少ない添加量で転写印刷法に好適なインクとすることができる。更に、高沸点溶剤の添加量を必要最小限とすることで、シリコーンブランケット上に塗布したインクを短時間に半乾燥させることができ、印刷タクトを短くすることができるという効果を奏する。 In the present invention, the “high boiling point solvent” refers to a solvent having a boiling point of 200 ° C. or higher. In addition, since it has a suitable affinity for water by having a hydroxyl group and tends to absorb or absorb moisture in the air and moisturize it, an ink suitable for transfer printing with a small addition amount can be obtained. can do. Furthermore, by minimizing the amount of the high-boiling solvent added, the ink applied on the silicone blanket can be semi-dried in a short time, and the printing tact can be shortened.
　水酸基を有する高沸点溶剤の添加量は、０．１～３．０質量％である。０．１質量％未満であると、量が少なすぎて転写印刷法に好適なインク状になりにくく、３．０質量％を超えると、転写印刷法に好適な半乾燥状態に到達する時間が長くなり印刷タクトの面で不利となる。水酸基を有する高沸点溶剤の添加量は、０．３～２．０質量％であるのが、より確実に、転写印刷法に好適なインク状になり易く、転写印刷法に好適な半乾燥状態に到達する時間を短くでき印刷タクトの面で有利となるという観点から、特に好ましい。 The addition amount of the high boiling point solvent having a hydroxyl group is 0.1 to 3.0% by mass. If the amount is less than 0.1% by mass, the amount is too small to easily form an ink suitable for the transfer printing method. If the amount exceeds 3.0% by mass, the time to reach a semi-dry state suitable for the transfer printing method is reached. It becomes longer and disadvantageous in terms of printing tact. The addition amount of the high boiling point solvent having a hydroxyl group is 0.3 to 2.0% by mass, but it is more sure that the ink is suitable for the transfer printing method, and it is a semi-dry state suitable for the transfer printing method. This is particularly preferable from the viewpoint of shortening the time required to reach the position and being advantageous in terms of printing tact.
　また、本発明の転写印刷用導電性インクにおいては、インクの乾燥性を高めるためにエタノール等の高揮発性溶剤を添加する。当該溶剤を添加することにより、転写印刷用導電性インクを素早く印刷に適した粘度に調整することができる。高揮発性溶剤としては、エタノールの他、メタノール、プロピルアルコール、イソプロピルアルコール、アセトン、ｎ－ブタノール、ｓｅｃ－ブタノール、ｔｅｒｔ－ブタノール等の沸点１００℃未満の溶剤の群から選ばれる１又は２以上の低沸点溶剤を用いることができる。 Further, in the conductive ink for transfer printing of the present invention, a highly volatile solvent such as ethanol is added in order to improve the drying property of the ink. By adding the solvent, the transfer printing conductive ink can be quickly adjusted to a viscosity suitable for printing. Examples of the highly volatile solvent include one or more selected from the group of solvents having a boiling point of less than 100 ° C. such as ethanol, methanol, propyl alcohol, isopropyl alcohol, acetone, n-butanol, sec-butanol, tert-butanol and the like. Low boiling solvents can be used.
　更に、本発明の転写印刷用導電性インクにおいては、ハイドロフルオロエーテル等のフッ素溶剤を含んでいることが好ましい。フッ素溶剤は、表面張力が低いためにシリコーンブランケットに対し良好な濡れ性を発揮させることができ、沸点が比較的低いために良好な乾燥性を付与することができる。なかでも、オゾン破壊係数の観点から、ハロゲン原子を含むフッ素溶剤よりもハイドロフルオロエーテルのほうが好ましい。 Furthermore, the conductive ink for transfer printing of the present invention preferably contains a fluorine solvent such as hydrofluoroether. Since the fluorine solvent has a low surface tension, it can exhibit good wettability with respect to the silicone blanket, and since the boiling point is relatively low, it can provide good drying properties. Of these, hydrofluoroethers are more preferable than fluorine solvents containing halogen atoms from the viewpoint of the ozone depletion coefficient.
　また、ハイドロフルオロエーテルは、ハイドロフルオロカーボン類よりもエーテル結合を有しているために極性が高く、シリコーンブランケットをほとんど膨潤させないという利点を有しており、エタノール等のアルコールとの相溶性が良く、アルコールに分散した金属粒子との相溶性にも優れるという効果を奏するため、より好ましい。 In addition, hydrofluoroether has an ether bond than hydrofluorocarbons, so it has a high polarity and has the advantage of hardly causing the silicone blanket to swell, and has good compatibility with alcohols such as ethanol, This is more preferable because it has an effect of being excellent in compatibility with metal particles dispersed in alcohol.
　本発明の転写印刷用導電性インクにおいては、シリコーンブランケットに対する濡れ性を向上させる目的で、フッ素原子を有するフッ素系界面活性剤を添加してもよい。ただし、この場合、添加量が多過ぎると転写印刷用導電性インクを用いて作製した導電性被膜の導電性が低下し、添加量が少な過ぎると濡れ性改善の効果が不十分であるため、０．０１～２質量％であるのが好適である。 In the conductive ink for transfer printing of the present invention, a fluorine-based surfactant having a fluorine atom may be added for the purpose of improving the wettability with respect to the silicone blanket. However, in this case, if the addition amount is too large, the conductivity of the conductive film produced using the conductive ink for transfer printing is lowered, and if the addition amount is too small, the effect of improving the wettability is insufficient. The content is preferably 0.01 to 2% by mass.
　本発明の転写印刷用導電性インクにおいては、表面張力が２２ｍＮ／ｍ以下である。表面張力を２２ｍＮ／ｍ以下と十分に下げることで、シリコーン樹脂等のブランケットへの転写印刷用導電性インクの濡れ性を十分に担保することができる。表面張力を２２ｍＮ／ｍ以下にすることは、上記の本発明の転写印刷用導電性インクの成分比を調整することによって実現できる。表面張力の下限は１３ｍＮ／ｍ程度であればよい。なお、本発明においていう表面張力とは、プレート法（Ｗｉｌｈｅｌｍｙ法）という原理で測定して得られるものであり、例えば、協和界面科学（株）製の全自動表面張力計ＣＢＶＰ－Ｚ等により測定することができる。 In the conductive ink for transfer printing of the present invention, the surface tension is 22 mN / m or less. By sufficiently lowering the surface tension to 22 mN / m or less, the wettability of the conductive ink for transfer printing onto a blanket such as a silicone resin can be sufficiently ensured. The surface tension of 22 mN / m or less can be realized by adjusting the component ratio of the conductive ink for transfer printing according to the present invention. The lower limit of the surface tension may be about 13 mN / m. The surface tension referred to in the present invention is obtained by measurement based on the principle of the plate method (Wilhelmy method). For example, the surface tension is measured by a fully automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. can do.
　ここで、本実施形態の転写印刷用導電性インクは、銀微粒子と、炭素数が５以下であり分配係数ｌｏｇＰが－１．０～１．４である短鎖アミンと、高極性溶媒と、前記銀微粒子を分散させるための酸価を有する分散剤と、を含む銀微粒子分散体（例えばコロイド状）で構成されていることが好ましい。以下においてこの銀微粒子分散体及び各成分等の詳細について説明する。 Here, the conductive ink for transfer printing of the present embodiment includes silver fine particles, a short-chain amine having a carbon number of 5 or less and a distribution coefficient log P of −1.0 to 1.4, a high-polarity solvent, It is preferable to be composed of a silver fine particle dispersion (for example, colloidal) containing a dispersant having an acid value for dispersing the silver fine particles. Details of the silver fine particle dispersion and each component will be described below.
　本実施形態の銀微粒子分散体は、銀微粒子と、炭素数が５以下である短鎖アミンと、高極性溶媒と、を含んでおり、例えばコロイド状のコロイド液の形態を有している。銀微粒子分散体の固形分に含まれる銀微粒子（銀コロイド粒子）の形態に関しては、例えば、銀成分からなる粒子の表面に有機成分が付着して構成されている銀コロイド粒子、上記銀成分からなる粒子をコアとして、その表面が有機成分で被覆されて構成されている銀コロイド粒子、銀成分と有機成分とが均一に混合されて構成されている銀コロイド粒子等が挙げられるが、特に限定されない。銀成分からなる粒子をコアとして、その表面が有機成分で被覆されて構成されている銀コロイド粒子、又は銀成分と有機成分とが均一に混合されて構成されている銀コロイド粒子が好ましい。なお、当業者は、上述した形態を有する銀コロイド粒子を、当該分野における周知技術を用いて適宜調製することができる。 The silver fine particle dispersion of the present embodiment contains silver fine particles, a short-chain amine having 5 or less carbon atoms, and a highly polar solvent, and has, for example, a colloidal colloidal liquid form. Regarding the form of silver fine particles (silver colloidal particles) contained in the solid content of the silver fine particle dispersion, for example, silver colloidal particles formed by adhering organic components to the surface of particles composed of silver components, Silver colloidal particles whose surface is coated with an organic component and silver colloidal particles that are configured by uniformly mixing a silver component and an organic component are included. Not. Silver colloidal particles having a particle composed of a silver component as a core and the surface of which is coated with an organic component, or silver colloidal particles formed by uniformly mixing a silver component and an organic component are preferable. A person skilled in the art can appropriately prepare the colloidal silver particles having the above-described form using a well-known technique in this field.
（１－１）銀微粒子
　本実施形態における銀微粒子分散体に含まれる銀微粒子の平均粒径は、本発明の効果を損なわない範囲であれば特に制限されるものではないが、融点降下が生じるような平均粒径を有するのが好ましく、例えば、１～４００ｎｍであればよい。更には、１～７０ｎｍであるのが好ましい。銀微粒子の平均粒径が１ｎｍ以上であれば、銀微粒子が良好な低温焼結性を具備すると共に銀微粒子製造がコスト高とならず実用的である。また、４００ｎｍ以下であれば、銀微粒子の分散性が経時的に変化しにくく、好ましい。なお、本実施形態の銀微粒子分散体を用いて得られる転写印刷用導電性インクにおいても、銀コロイド粒子（銀微粒子を含む。）の平均粒径（メディアン径）はこの範囲と略同じである（近似できる）。 (1-1) Silver Fine Particles The average particle diameter of the silver fine particles contained in the silver fine particle dispersion in the present embodiment is not particularly limited as long as the effects of the present invention are not impaired, but a melting point drop occurs. It is preferable to have such an average particle diameter, for example, it may be 1 to 400 nm. Further, it is preferably 1 to 70 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 400 nm or less, the dispersibility of a silver fine particle does not change easily over time, and it is preferable. In the conductive ink for transfer printing obtained using the silver fine particle dispersion of this embodiment, the average particle diameter (median diameter) of the silver colloid particles (including silver fine particles) is substantially the same as this range. (Can approximate)
　なお、銀微粒子分散体における銀微粒子の粒径は固形分濃度によって変動し、一定とは限らず、一定でなくてもよい。また、銀微粒子分散体が、任意成分として、後述する分散剤等を含む場合、平均粒径が４００ｎｍ超の銀微粒子成分を含む場合があるが、凝集を生じたりせず、本発明の効果を著しく損なわない成分であればかかる４００ｎｍ超の平均粒径を有する銀微粒子成分を含んでもよい。 Note that the particle size of the silver fine particles in the silver fine particle dispersion varies depending on the solid content concentration, and is not necessarily constant, and may not be constant. In addition, when the silver fine particle dispersion contains a dispersant described later as an optional component, the silver fine particle dispersion may contain a silver fine particle component having an average particle diameter of more than 400 nm. A silver fine particle component having an average particle diameter of more than 400 nm may be included as long as the component is not significantly impaired.
　ここで、本実施形態の銀微粒子分散体における銀微粒子の平均粒径は、動的光散乱法（ドップラー散乱光解析）によるもので、例えば、（株）堀場製作所製動的光散乱式粒径分布測定装置ＬＢ－５５０で測定した体積基準のメディアン径（Ｄ５０）で表すことができる。具体的には、エタノール１０ｍＬ中に金属コロイド液を数滴滴下し、手で振動し分散させて測定用試料を調製する。ついで、測定用試料３ｍＬを、（株）堀場製作所製動的光散乱式粒径分布測定装置ＬＢ－５５０、のセル内に投入し、下記の条件にて測定する。 Here, the average particle diameter of the silver fine particles in the silver fine particle dispersion of the present embodiment is based on the dynamic light scattering method (Doppler scattered light analysis). For example, the dynamic light scattering particle diameter manufactured by Horiba, Ltd. It can be represented by a volume-based median diameter (D50) measured by the distribution measuring device LB-550. Specifically, several drops of a metal colloid solution are dropped into 10 mL of ethanol, and are shaken and dispersed by hand to prepare a measurement sample. Next, 3 mL of the measurement sample is put into a cell of a dynamic light scattering particle size distribution measuring device LB-550 manufactured by Horiba, Ltd., and measurement is performed under the following conditions.
・測定条件
データ読み込み回数：１００回
セルホルダー内温度：２５℃
・表示条件
分布形態：標準
反復回数：５０回
粒子径基準：体積基準
分散質の屈折率：０．２００－３．９００ｉ（銀の場合）
分散媒の屈折率：１．３６（エタノールが主成分の場合）
・システム条件設定
強度基準：Ｄｙｎａｍｉｃ
散乱強度レンジ上限：１００００．００
散乱強度レンジ下限：１．００ ・ Measurement condition data read count: 100 times Cell holder temperature: 25 ° C
Display condition distribution form: Standard number of repetitions: 50 times Particle size standard: Volume-based refractive index of refractive index: 0.200-3.900i (in the case of silver)
Refractive index of dispersion medium: 1.36 (when ethanol is the main component)
・ System condition setting strength criteria: Dynamic
Scattering intensity range upper limit: 10000.00
Scattering intensity range lower limit: 1.00
（１－２）炭素数が５以下である短鎖アミン
　本実施形態の銀微粒子分散体において、銀微粒子の表面の少なくとも一部には炭素数が５以下である短鎖アミンが付着している。なお、銀微粒子の表面には、原料に最初から不純物として含まれる微量有機物、後述する製造過程で混入する微量有機物、洗浄過程で除去しきれなかった残留還元剤、残留分散剤等のように、微量の有機物が付着していてもよい。 (1-2) Short-chain amine having 5 or less carbon atoms In the silver fine particle dispersion of the present embodiment, a short-chain amine having 5 or less carbon atoms is attached to at least a part of the surface of the silver fine particles. . In addition, on the surface of the silver fine particles, a trace amount of organic matter contained as an impurity from the beginning, a trace amount of organic matter mixed in the manufacturing process described later, a residual reducing agent that could not be removed in the cleaning process, a residual dispersant, etc. A trace amount of organic matter may be attached.
　炭素数が５以下である短鎖アミンは分配係数ｌｏｇＰが－１．０～１．４であれば特に限定されず、直鎖状であっても分岐鎖状であってもよく、また、側鎖を有していてもよい。当該短鎖アミンとしては、例えば、エチルアミン（－０．３）プロピルアミン（０．５）、ブチルアミン（１．０）、Ｎ－（３-メトキシプロピル）プロパン-１,３-ジアミン（－０．６）、１,２-エタンジアミン, Ｎ－（３-メトキシプロピル）－（－０．９）, ２-メトキシエチルアミン（－０．９）、３－メトキシプロピルアミン（－０．５）、３－エトキシプロピルアミン（－０．１）、１，４－ブタンジアミン（－０．９）、１，５－ペンタンジアミン（－０．６）ペンタノールアミン（－０．３）、アミノイソブタノール（－０．８）等が挙げられるが、なかでもアルコキシアミンを用いることが好ましい。 The short-chain amine having 5 or less carbon atoms is not particularly limited as long as the distribution coefficient logP is −1.0 to 1.4, and may be linear or branched. You may have a chain. Examples of the short chain amine include ethylamine (−0.3) propylamine (0.5), butylamine (1.0), N- (3-methoxypropyl) propane-1,3-diamine (−0. 6) 1,2-ethanediamine, N- (3-methoxypropyl)-(-0.9), 2-methoxyethylamine (-0.9), 3-methoxypropylamine (-0.5), 3 -Ethoxypropylamine (-0.1), 1,4-butanediamine (-0.9), 1,5-pentanediamine (-0.6) pentanolamine (-0.3), aminoisobutanol ( -0.8), etc., among which alkoxyamine is preferably used.
　上記短鎖アミンは、例えば、ヒドロキシル基、カルボキシル基、アルコキシ基、カルボニル基、エステル基、メルカプト基等の、アミン以外の官能基を含む化合物であってもよい。また、上記アミンは、それぞれ単独で用いてもよく、２種以上を併用してもよい。加えて、常温での沸点が３００℃以下、更には２５０℃以下であることが好ましい。 The short chain 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 temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower.
　本実施形態の銀粒子分散体は、本発明の効果を損なわない範囲であれは、上記の炭素数が５以下である短鎖アミンに加えて、カルボン酸を含んでいてもよい。カルボン酸の一分子内におけるカルボキシル基が、比較的高い極性を有し、水素結合による相互作用を生じ易いが、これら官能基以外の部分は比較的低い極性を有する。更に、カルボキシル基は、酸性的性質を示し易い。また、カルボン酸は、本実施形態の銀粒子分散体中で、銀微粒子の表面の少なくとも一部に局在化（付着）すると（即ち、銀微粒子の表面の少なくとも一部を被覆すると）、溶媒と銀微粒子とを十分に親和させることができ、銀微粒子同士の凝集を防ぐことができる（分散性を向上させる。）。 The silver particle dispersion of the present embodiment may contain a carboxylic acid in addition to the short-chain amine having 5 or less carbon atoms 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. In addition, when the carboxylic acid is localized (attached) on at least a part of the surface of the silver fine particles (that is, covers at least a part of the surface of the silver fine particles) in the silver particle dispersion of the present embodiment, the solvent. And silver fine particles can be made to sufficiently adhere to each other and aggregation of silver fine particles can be prevented (dispersibility is improved).
　カルボン酸としては、少なくとも１つのカルボキシル基を有する化合物を広く用いることができ、例えば、ギ酸、シュウ酸、酢酸、ヘキサン酸、アクリル酸、オクチル酸、オレイン酸等が挙げられる。カルボン酸の一部のカルボキシル基が金属イオンと塩を形成していてもよい。なお、当該金属イオンについては、２種以上の金属イオンが含まれていてもよい。 As the 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. In addition, about the said metal ion, 2 or more types of metal ions may be contained.
　上記カルボン酸は、例えば、アミノ基、ヒドロキシル基、アルコキシ基、カルボニル基、エステル基、メルカプト基等の、カルボキシル基以外の官能基を含む化合物であってもよい。この場合、カルボキシル基の数が、カルボキシル基以外の官能基の数以上であることが好ましい。また、上記カルボン酸は、それぞれ単独で用いてもよく、２種以上を併用してもよい。加えて、常温での沸点が３００℃以下、更には２５０℃以下であることが好ましい。また、アミンとカルボン酸はアミドを形成する。当該アミド基も銀微粒子表面に適度に吸着するため、銀微粒子表面にはアミド基が付着していてもよい。 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. In this case, the number of carboxyl groups is preferably equal to or greater than the number of functional groups other than carboxyl groups. Moreover, the said carboxylic acid may be used independently, respectively and may use 2 or more types together. In addition, the boiling point at normal temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower. Also, amines and carboxylic acids form amides. Since the amide group also adsorbs moderately on the surface of the silver fine particles, the amide group may adhere to the surface of the silver fine particles.
　銀微粒子と当該銀微粒子の表面に付着した有機物（上記炭素数が５以下である短鎖アミン等）によってコロイドが構成される場合、当該コロイド中の有機成分の含有量は、０．５～５０質量％であることが好ましい。有機成分含有量が０．５質量％以上であれば、得られる銀微粒子分散体の貯蔵安定性が良くなる傾向があり、５０質量％以下であれば、銀微粒子分散体を加熱して得られる焼成体の導電性が良い傾向がある。有機成分のより好ましい含有量は１～３０質量％であり、更に好ましい含有量は２～１５質量％である。 When the colloid is composed of silver fine particles and organic substances (such as the short-chain amine having 5 or less carbon atoms) attached to the surface of the silver fine particles, the content of the organic component in the colloid is 0.5 to 50 It is preferable that it is mass%. If the organic component content is 0.5% by mass or more, the storage stability of the resulting silver fine particle dispersion tends to be improved, and if it is 50% by mass or less, the silver fine particle dispersion is obtained by heating. There exists a tendency for the electroconductivity of a sintered body to be good. 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.
（１－３）高極性溶媒
　本実施形態の銀微粒子分散体は、種々の高極性溶媒に銀微粒子が分散したものである。 (1-3) High Polar Solvent The silver fine particle dispersion of the present embodiment is a dispersion of silver fine particles in various high polar solvents.
　上記溶媒としては、本発明の効果を損なわない範囲で、種々の高極性溶媒を用いることができる。高極性溶媒としては、メタノール、エタノール、プロパノール、イソプロパノール、ブタノール、イソブタノール、２－ブタノール、ペンタノール、ヘキサノール、イソアミルアルコール、フルフリルアルコール、ニトロメタン、アセトニトリル、ピリジン、アセトンクレゾール、ジメチルホルムアミド、ジオキサン、エチレングリコール、グリセリン、フェノール、ｐ－クレゾール、酢酸プロピル、酢酸イソプロピル、ｔｅｒｔ－ブタノール、１－ペンタノール、２－ペンタノール、４－メチル－２－ペンタノール、３－メチル－１－ペンタノール、３－メチル－２－ペンタノール、２－ブタノール、１－ヘキサノール、２－ヘキサノール２－ペンタノン、２－ヘプタノン、酢酸２－（２－エトキシエトキシ)エチル、酢酸－２－ブトキシエチル、酢酸２－（２－ブトキシエトキシ)エチル、酢酸－２－メトキシエチル、２－ヘキシルオキシエタノール等を例示することができるが、本発明では前記炭素数が５以下の短鎖アミンと相溶性が良好であるため、炭素数１～６のアルコールを用いることが好ましい。なお、これらの溶媒はそれぞれ単独で用いてもよく、２種以上を併用してもよい。 As the solvent, various highly polar solvents can be used as long as the effects of the present invention are not impaired. High polar solvents include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-butanol, pentanol, hexanol, isoamyl alcohol, furfuryl alcohol, nitromethane, acetonitrile, pyridine, acetone cresol, dimethylformamide, dioxane, ethylene Glycol, glycerin, phenol, p-cresol, propyl acetate, isopropyl acetate, tert-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 3-methyl-1-pentanol, 3- Methyl-2-pentanol, 2-butanol, 1-hexanol, 2-hexanol 2-pentanone, 2-heptanone, 2- (2-ethoxyethoxy) ethyl acetate, 2-butoxye acetate Examples include chill, 2- (2-butoxyethoxy) ethyl acetate, 2-methoxyethyl acetate, 2-hexyloxyethanol, etc., but the present invention is compatible with the short-chain amine having 5 or less carbon atoms. Therefore, it is preferable to use an alcohol having 1 to 6 carbon atoms. These solvents may be used alone or in combination of two or more.
（１－４）分散剤
　本実施形態の銀粒子分散体には、更に、銀微粒子を分散させるために銀微粒子合成後に添加される「酸価を有する分散剤」を含む。かかる分散剤を用いることで、溶媒中の銀微粒子の分散安定性を向上させることができる。ここで、当該分散剤の酸価は５～２００であることがより好ましく、また、当該分散剤がリン酸由来の官能基を有することが更に好ましい。 (1-4) Dispersant The silver particle dispersion of the present embodiment further includes a “dispersant having an acid value” added after the synthesis of silver fine particles in order to disperse the silver fine particles. By using such a dispersant, the dispersion stability of the silver fine particles in the solvent can be improved. Here, the acid value of the dispersant is more preferably from 5 to 200, and it is further preferable that the dispersant has a functional group derived from phosphoric acid.
　分散剤の酸価が５以上であるとアミンと配位し粒子表面が塩基性となっている金属物への酸塩基相互作用での吸着が起こり始めるからであり、２００以下であると過度に吸着サイトを有さないため好適な形態で吸着するからである。また、分散剤がリン酸由来の官能基を有することでリンＰが酸素Ｏを介して金属Ｍと相互作用し引き合うので金属や金属化合物との吸着には最も効果的であり、必要最小限の吸着量で好適な分散性を得ることができるからである。 If the acid value of the dispersant is 5 or more, adsorption with an acid-base interaction starts to occur on a metal substance that coordinates with the amine and the particle surface is basic. This is because it does not have an adsorption site and adsorbs in a suitable form. In addition, since the dispersant has a functional group derived from phosphoric acid, phosphorus P interacts with and attracts the metal M through the oxygen O, and is therefore most effective for adsorption with metals and metal compounds. This is because suitable dispersibility can be obtained by the amount of adsorption.
　なお、酸価が５～２００の高分子分散剤としては、例えば、ルーブリゾール社のＳＯＬＳＰＥＲＳＥシリーズではＳＯＬＳＰＥＲＳＥ－１６０００、２１０００、４１０００、４１０９０、４３０００、４４０００、４６０００、５４０００等が挙げられ、ビックケミー社ＤＩＳＰＥＲＢＹＫシリーズではＤＩＳＰＥＲＢＹＫ－１０２、１１０、１１１、１７０、１９０．１９４Ｎ、２０１５．２０９０、２０９６等が挙げられ、エボニック社のＴＥＧＯ Ｄｉｓｐｅｒｓシリーズでは６１０、６１０Ｓ、６３０、６５１、６５５、７５０Ｗ、７５５Ｗ等が挙げられ、楠本化成(株)製のディスパロンシリーズではＤＡ－３７５、ＤＡ－１２００等が挙げられ、共栄化学工業(株)製のフローレンシリーズではＷＫ－１３Ｅ、Ｇ－７００、Ｇ－９００、ＧＷ－１５００、ＧＷ－１６４０、ＷＫ－１３Ｅを例示することができる。 Examples of the polymer dispersant having an acid value of 5 to 200 include SOLPERSE-16000, 21000, 41000, 41090, 43000, 44000, 46000, and 54000 in the SOLSPERSE series of Lubrizol. In the series, DISPERBYK-102, 110, 111, 170, 190.194N, 2015.2090, 2096 and the like are listed, and in Evonik's TEGO® Dispers series, 610, 610S, 630, 651, 655, 750W, 755W and the like are listed. In the Disparon series manufactured by Enomoto Kasei Co., Ltd., DA-375, DA-1200 and the like are listed. In the Floren series manufactured by Kyoei Chemical Industry Co., Ltd., WK-13E, G-700, G-9. The 0, GW-1500, GW-1640, WK-13E can be exemplified.
　本実施形態の銀微粒子分散体に分散剤を含有させる場合の含有量は、粘度などの所望の特性によって調整すれば良いが、例えば、銀微粒子分散体を銀インクとして用いる場合は、分散剤の含有量を０．５～２０質量％とすることが好ましく、銀ペーストとして用いる場合は、分散剤の含有量を０．１～１０質量％とすることが好ましい。 The content when the dispersant is contained in the silver fine particle dispersion of the present embodiment may be adjusted according to desired properties such as viscosity. For example, when the silver fine particle dispersion is used as a silver ink, The content is preferably 0.5 to 20% by mass, and when used as a silver paste, the content of the dispersant is preferably 0.1 to 10% by mass.
　高分子分散剤の含有量は０．１～１５質量％であることが好ましい。高分子分散剤の含有量が０．１％以上であれば得られる銀微粒子分散体の分散安定性が良くなるが、含有量が多過ぎる場合は低温焼結性が低下することとなる。このような観点から、高分子分散剤のより好ましい含有量は０．３～１０質量％であり、更に好ましい含有量は０．５～８質量％である。 The content of the polymer dispersant is preferably 0.1 to 15% by mass. When the content of the polymer dispersant is 0.1% or more, the dispersion stability of the obtained silver fine particle dispersion is improved. However, when the content is too large, the low-temperature sinterability is lowered. From such a viewpoint, the more preferable content of the polymer dispersant is 0.3 to 10% by mass, and still more preferable content is 0.5 to 8% by mass.
　本実施形態の銀微粒子分散体は、固形分に対して１０℃／分の昇温速度で熱重量分析を行ったときの１００～５００℃における重量損失が１０質量％以下であることが好ましい。上記固形物を５００℃まで加熱すると、有機物などが酸化分解され、大部分はガス化されて消失する。このため、５００℃までの加熱による減量は、ほぼ固形分中の有機物の量に相当し得る。 The silver fine particle dispersion of this embodiment preferably has a weight loss of 10% by mass or less at 100 to 500 ° C. when thermogravimetric analysis is performed at a rate of temperature increase of 10 ° C./min with respect to the solid content. When the solid is heated to 500 ° C., organic matter and the like are oxidatively decomposed, and most of them are gasified and disappear. For this reason, the reduction | decrease by heating to 500 degreeC can correspond to the quantity of the organic substance in solid content substantially.
　上記重量損失が多いほど銀微粒子分散体の分散安定性は優れるが、多過ぎると有機物が不純物として転写印刷用導電性インクに残留して、導電性を低下させる。特に１００℃程度の低温での加熱によって導電性の高い導電膜パターンを得るためには、上記重量損失が２０質量％以下であることが好ましい。一方、上記重量損失が少な過ぎるとコロイド状態での分散安定性が損なわれるため、０．１質量％以上であることが好ましい。より好ましい重量損失は０．５～１５質量％である。 The greater the weight loss, the better the dispersion stability of the silver fine particle dispersion, but if it is too much, the organic matter remains as impurities in the conductive ink for transfer printing, and the conductivity is lowered. In particular, in order to obtain a conductive film pattern having high conductivity by heating at a low temperature of about 100 ° C., the weight loss is preferably 20% by mass or less. On the other hand, since the dispersion stability in a colloidal state is impaired when the weight loss is too small, the content is preferably 0.1% by mass or more. A more preferred weight loss is 0.5 to 15% by mass.
（１－５）保護剤（保護分散剤）
　本実施形態の銀微粒子分散体は、更に、銀微粒子合成前に添加される保護剤としての酸価を有する分散剤（保護分散剤）を含んでいてもよい。ここでいう「保護分散剤」は、上記の銀微粒子合成後に添加される「酸価を有する分散剤」と同じ種類のものでも異なる種類のものであってもよい。 (1-5) Protective agent (protective dispersant)
The silver fine particle dispersion of this embodiment may further contain a dispersant (protective dispersant) having an acid value as a protective agent added before the synthesis of the silver fine particles. The “protective dispersant” referred to here may be of the same type or different type as the “dispersant having an acid value” added after the synthesis of the silver fine particles.
（１－５）その他の成分
　本実施形態の銀微粒子分散体には、上記の成分に加えて、本発明の効果を損なわない範囲で、使用目的に応じた適度な粘性、密着性、乾燥性又は印刷性等の機能を付与するために、例えばバインダとしての役割を果たすオリゴマー成分、樹脂成分、有機溶剤（固形分の一部を溶解又は分散していてよい。）、界面活性剤、増粘剤又は表面張力調整剤等の任意成分を添加してもよい。かかる任意成分としては、特に限定されない。 (1-5) Other components In addition to the above components, the silver fine particle dispersion of the present embodiment has an appropriate viscosity, adhesiveness, and drying property in accordance with the purpose of use within a range not impairing the effects of the present invention. Or, in order to provide functions such as printability, for example, an oligomer component that plays a role as a binder, a resin component, an organic solvent (a part of the solid content may be dissolved or dispersed), a surfactant, a thickening agent. You may add arbitrary components, such as an agent or a surface tension regulator. Such optional components are not particularly limited.
　樹脂成分としては、例えば、ポリエステル系樹脂、ブロックドイソシアネート等のポリウレタン系樹脂、ポリアクリレート系樹脂、ポリアクリルアミド系樹脂、ポリエーテル系樹脂、メラミン系樹脂又はテルペン系樹脂等を挙げることができ、これらはそれぞれ単独で用いてもよく、２種以上を併用してもよい。 Examples of the resin component 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.
　増粘剤としては、例えば、クレイ、ベントナイト又はヘクトライト等の粘土鉱物、例えば、ポリエステル系エマルジョン樹脂、アクリル系エマルジョン樹脂、ポリウレタン系エマルジョン樹脂又はブロックドイソシアネート等のエマルジョン、メチルセルロース、カルボキシメチルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロースのセルロース誘導体、キサンタンガム又はグアーガム等の多糖類等が挙げられ、これらはそれぞれ単独で用いてもよく、２種以上を併用してもよい。 Examples of the thickener 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. , Hydroxypropylcellulose, cellulose derivatives of hydroxypropylmethylcellulose, polysaccharides such as xanthan gum or guar gum, etc., and these may be used alone or in combination of two or more.
　上記有機成分とは異なる界面活性剤を添加してもよい。多成分溶媒系の無機コロイド分散液においては、乾燥時の揮発速度の違いによる被膜表面の荒れ及び固形分の偏りが生じ易い。本実施形態の銀微粒子分散体に界面活性剤を添加することによってこれらの不利益を抑制し、均一な導電性被膜を形成することができる銀微粒子分散体が得られる。 A surfactant different from the above organic components may be added. In a multi-component solvent-based inorganic colloidal dispersion, the coating surface becomes rough and the solid content tends to be uneven due to the difference in volatilization rate during drying. By adding a surfactant to the silver fine particle dispersion of this embodiment, a silver fine particle dispersion capable of suppressing these disadvantages and forming a uniform conductive film can be obtained.
　本実施形態において用いることのできる界面活性剤としては、特に限定されず、アニオン性界面活性剤、カチオン性界面活性剤、ノニオン性界面活性剤の何れかを用いることができ、例えば、アルキルベンゼンスルホン酸塩、４級アンモニウム塩等が挙げられる。なかでも、少量の添加量で効果が得られるので、フッ素系界面活性剤、シリコーン系界面活性剤が好ましい。界面活性剤の含有量は少な過ぎると効果が得られず、多過ぎると被膜中で残量不純物となるため、導電性が阻害されるおそれがある。好ましい界面活性剤の含有量は、銀微粒子分散体の分散媒１００質量部に対して０．０１～５質量部である。 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, alkylbenzene sulfonic acid Salt, quaternary ammonium salt and the like. Of these, fluorine-based surfactants and silicone-based surfactants are preferred because an effect can be obtained with a small amount of addition. If the content of the surfactant is too small, the effect cannot be obtained. If the content is too large, the remaining amount of impurities in the coating becomes an impurity, so that the conductivity may be hindered. A preferable surfactant content is 0.01 to 5 parts by mass with respect to 100 parts by mass of the dispersion medium of the silver fine particle dispersion.
　本実施形態における銀微粒子は、表面の少なくとも一部に分配係数ｌｏｇＰが－１．０～１．４であり炭素数が５以下であるアルコキシアミンが付着した銀微粒子である。銀微粒子の表面の少なくとも一部に分配係数ｌｏｇＰが－１．０～１．４である炭素数が５以下のアルコキシアミンを付着させることで、銀微粒子に種々の溶媒（特に高極性溶媒）に対する優れた分散性と低温焼結性とを付与することができる。 The silver fine particles in the present embodiment are silver fine particles in which an alkoxyamine having a distribution coefficient logP of −1.0 to 1.4 and a carbon number of 5 or less is attached to at least a part of the surface. By attaching an alkoxyamine having a partition coefficient logP of −1.0 to 1.4 and having 5 or less carbon atoms to at least a part of the surface of the silver fine particles, the silver fine particles can be used for various solvents (particularly highly polar solvents). Excellent dispersibility and low-temperature sinterability can be imparted.
　上記溶媒としては、本発明の効果を損なわない範囲で、種々の溶媒を用いることができ、ＳＰ値（溶解パラメーター）が７．０～１５．０である溶媒を用いることができる。ここで、高極性溶媒中においても銀微粒子が均一に分散していることが本発明の銀微粒子分散体の特徴の一つであり、本発明では前記炭素数が５以下の短鎖アミンと相溶性が良好であるため、炭素数１～６のアルコールを用いることが好ましい。なお、これらの溶媒はそれぞれ単独で用いてもよく、２種以上を併用してもよい。 As the solvent, various solvents can be used as long as the effects of the present invention are not impaired, and a solvent having an SP value (solubility parameter) of 7.0 to 15.0 can be used. Here, it is one of the characteristics of the silver fine particle dispersion of the present invention that the silver fine particles are uniformly dispersed even in a highly polar solvent. In the present invention, the phase is combined with the short-chain amine having 5 or less carbon atoms. It is preferable to use an alcohol having 1 to 6 carbon atoms because of good solubility. These solvents may be used alone or in combination of two or more.
　ＳＰ値（溶解パラメーター）が７．０～１５．０である溶媒としては、例えば、ヘキサン（７．２）、トリエチルアミン（７．３）、エチルエーテル（７．７）、ｎ－オクタン（７．８）、シクロヘキサン（８．３）、ｎ－アミルアセテート（８．３）、酢酸イソブチル（８．３）、メチルイソプロピルケトン（８．４）、アミルベンゼン（８．５）酢酸ブチル（８．５）、四塩化炭素（８．６）、エチルベンゼン（８．７）、ｐ－キシレン（８．８）、トルエン（８．９）、メチルプロピルケトン（８．９）酢酸エチル（８．９）、テトラヒドロフラン（９．２）、メチルエチルケトン（９．３）、クロロホルム（９．４）、アセトン（９．８）、ジオキサン（１０．１）、ピリジン（１０．８）、イソブタノール（１１．０）、ｎ－ブタノール（１１．１）、ニトロエタン（１１．１）イソプロピルアルコール（１１．２）、ｍ－クレゾール（１１．４）、アセトニトリル（１１．９）、ｎ－プロパノール（１２．１）、フルフリルアルコール（１２．５）、ニトロメタン（１２．７）、エタノール（１２．８）、クレゾール（１３．３）、エチレングリコール（１４．２）、メタノール（１４．８）フェノール、ｐ－クレゾール、酢酸プロピル、酢酸イソプロピル、ｔｅｒｔ－ブタノール、１－ペンタノール、２－ペンタノール、４－メチル－２－ペンタノール、３－メチル－１－ペンタノール、３－メチル－２－ペンタノール、２－ブタノール、１－ヘキサノール、２－ヘキサノール２－ペンタノン、２－ヘプタノン、酢酸２－（２－エトキシエトキシ)エチル、酢酸－２－ブトキシエチル、酢酸２－（２－ブトキシエトキシ)エチル、酢酸－２－メトキシエチル、２－ヘキシルオキシエタノール等を例示することができる。 Examples of the solvent having an SP value (solubility parameter) of 7.0 to 15.0 include hexane (7.2), triethylamine (7.3), ethyl ether (7.7), and n-octane (7. 8), cyclohexane (8.3), n-amyl acetate (8.3), isobutyl acetate (8.3), methyl isopropyl ketone (8.4), amyl benzene (8.5) butyl acetate (8.5) ), Carbon tetrachloride (8.6), ethylbenzene (8.7), p-xylene (8.8), toluene (8.9), methyl propyl ketone (8.9) ethyl acetate (8.9), Tetrahydrofuran (9.2), methyl ethyl ketone (9.3), chloroform (9.4), acetone (9.8), dioxane (10.1), pyridine (10.8), isobutanol (11.0), n-bu Nord (11.1), Nitroethane (11.1) Isopropyl alcohol (11.2), m-cresol (11.4), acetonitrile (11.9), n-propanol (12.1), furfuryl alcohol ( 12.5), nitromethane (12.7), ethanol (12.8), cresol (13.3), ethylene glycol (14.2), methanol (14.8) phenol, p-cresol, propyl acetate, acetic acid Isopropyl, tert-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 2-butanol, 1-hexanol 2-hexanol 2-pentanone, 2-heptanone, 2- (2-ethoxyethoxy) ethyl acetate, acetic acid-2 Butoxyethyl, 2- (2-butoxyethoxy) ethyl acetate, acetic acid-2-methoxyethyl, can be exemplified 2-hexyloxy ethanol.
　本実施形態の銀微粒子分散体の粘度は、１～１００ｃｐｓの粘度範囲であることが望ましく、１～２０ｃｐｓの粘度範囲がより好ましい。当該粘度範囲とすることにより、シリコーン樹脂上に銀微粒子分散体を均一かつ薄膜状に塗布することができる。塗布する方法には汎用の塗布方法を利用することができ、アプリケータ法、バーコーター法、キャピラリーコータ法、及びスピンコーティング法等を例示することができる。 The viscosity of the silver fine particle dispersion of this embodiment is preferably in the viscosity range of 1 to 100 cps, and more preferably in the viscosity range of 1 to 20 cps. By setting it as the said viscosity range, a silver fine particle dispersion can be apply | coated uniformly and in thin film form on a silicone resin. A general-purpose coating method can be used as the coating method, and examples include an applicator method, a bar coater method, a capillary coater method, and a spin coating method.
　本実施形態の銀微粒子分散体の粘度の調整は、固形分濃度の調整、各成分の配合比の調整、増粘剤の添加等によって行うことができる。また、粘度は、振動式粘度計（例えばＣＢＣ（株）製のＶＭ－１００Ａ－Ｌ）により測定できる。測定は振動子に液を浸漬させて行い、測定温度は常温（２０～２５℃）とすればよい。 The viscosity of the silver fine particle dispersion of the present embodiment can be adjusted by adjusting the solid content concentration, adjusting the blending ratio of each component, adding a thickener, and the like. The viscosity can be measured with a vibration viscometer (for example, VM-100A-L manufactured by CBC Corporation). The measurement is performed by immersing the liquid in the vibrator, and the measurement temperature may be normal temperature (20 to 25 ° C.).
（２）転写印刷用導電性インクの製造方法
　本実施形態の転写印刷用導電性インクを製造するためには、まず、銀微粒子分散体（金属コロイド液）を調製する。ついで、この金属コロイド液と、上記各種成分とを混合することにより、本実施形態の導電性インクを得ることができる。 (2) Method for Producing Transfer Printing Conductive Ink To produce the transfer printing conductive ink of the present embodiment, first, a silver fine particle dispersion (metal colloid liquid) is prepared. Subsequently, the conductive ink of this embodiment can be obtained by mixing this metal colloid liquid and the above-mentioned various components.
　なかでも、本実施形態の銀微粒子分散体は、銀微粒子を生成する工程と、前記銀微粒子に、前記銀微粒子を分散させるための酸価を有する分散剤を添加・混合する工程と、を有するものである。更には、還元により分解して金属銀を生成しうる銀化合物と、分配係数ｌｏｇＰが－１．０～１．４である短鎖アミンと、の混合液を調整する第１前工程と、当該混合液中の前記銀化合物を還元することで表面の少なくとも一部に炭素数が５以下である短鎖アミンが付着した銀微粒子を生成する第２前工程と、を含むのが好ましい。 Among these, the silver fine particle dispersion of the present embodiment includes a step of generating silver fine particles, and a step of adding and mixing a dispersant having an acid value for dispersing the silver fine particles to the silver fine particles. Is. Furthermore, a first pre-process for preparing a mixture of a silver compound that can be decomposed by reduction to produce metallic silver and a short-chain amine having a partition coefficient log P of −1.0 to 1.4, It is preferable to include a second pre-process of reducing the silver compound in the mixed solution to generate silver fine particles having a short-chain amine having 5 or less carbon atoms attached to at least a part of the surface.
　上記第１前工程においては、短鎖アミンを金属銀１ｍｏｌに対して２ｍｏｌ以上添加すること、が好ましい。短鎖アミンの添加量を金属銀１ｍｏｌに対して２ｍｏｌ以上とすることで、還元によって生成される銀微粒子の表面に短鎖アミンを適量付着させることができ、当該銀微粒子に種々の溶媒（特に高極性溶媒）に対する優れた分散性と低温焼結性とを付与することができる。 In the first pre-process, it is preferable to add 2 mol or more of short chain amine to 1 mol of metallic silver. By setting the addition amount of the short chain amine to 2 mol or more with respect to 1 mol of metallic silver, an appropriate amount of the short chain amine can be attached to the surface of the silver fine particles produced by the reduction, and various solvents (particularly, Excellent dispersibility and low-temperature sinterability with respect to a highly polar solvent) can be imparted.
　なお、上記第１前工程における混合液の組成及び上記第２前工程における還元条件（例えば、加熱温度及び加熱時間等）によって、得られる銀微粒子の粒径を融点降下が生じるようなナノメートルサイズとすることが好ましく、１～２００ｎｍとすることがより好ましい。ここで、必要に応じてミクロンメートルサイズの粒子が含まれていてもよい。 It should be noted that 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, heating time, etc.) in the second pre-process. Preferably, the thickness is 1 to 200 nm. Here, particles of micrometer size may be included as necessary.
　上記第２前工程で得られる銀微粒子分散体から銀微粒子を取り出す方法は特に限定されないが、例えば、その銀微粒子分散体の洗浄を行う方法等が挙げられる。 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.
　有機物（分配係数ｌｏｇＰが－１．０～１．４である短鎖アミン）で被覆された銀微粒子を得るための出発材料としては、種々の公知の銀化合物（金属塩又はその水和物）を用いることができ、例えば、硝酸銀、硫酸銀、塩化銀、酸化銀、酢酸銀、シュウ酸銀、ギ酸銀、亜硝酸銀、塩素酸銀、硫化銀等の銀塩が挙げられる。これらは還元可能なものであれば特に限定されず、適当な溶媒中に溶解させても、溶媒中に分散させたまま使用してもよい。また、これらは単独で用いても複数併用してもよい。 As a starting material for obtaining silver fine particles coated with an organic substance (short chain amine having a partition coefficient log P of −1.0 to 1.4), various known silver compounds (metal salts or hydrates thereof) are used. Examples of the silver salt include silver salts such as silver nitrate, silver sulfate, silver chloride, 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.
　また、上記原料液においてこれらの銀化合物を還元する方法は特に限定されず、例えば、還元剤を用いる方法、紫外線等の光、電子線、超音波又は熱エネルギーを照射する方法、加熱する方法等が挙げられる。なかでも、操作の容易の観点から、還元剤を用いる方法が好ましい。 In addition, the method for reducing these silver compounds in the raw material liquid is not particularly limited. For example, 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. Among these, a method using a reducing agent is preferable from the viewpoint of easy operation.
　上記還元剤としては、例えば、ジメチルアミノエタノール、メチルジエタノールアミン、トリエタノールアミン、フェニドン、ヒドラジン等のアミン化合物；例えば、水素化ホウ素ナトリウム、ヨウ素化水素、水素ガス等の水素化合物；例えば、一酸化炭素、亜硫酸等の酸化物；例えば、硫酸第一鉄、酸化鉄、フマル酸鉄、乳酸鉄、シュウ酸鉄、硫化鉄、酢酸スズ、塩化スズ、二リン酸スズ、シュウ酸スズ、酸化スズ、硫酸スズ等の低原子価金属塩；例えば、エチレングリコール、グリセリン、ホルムアルデヒド、ハイドロキノン、ピロガロール、タンニン、タンニン酸、サリチル酸、Ｄ－グルコース等の糖等が挙げられるが、分散媒に溶解し上記金属塩を還元し得るものであれば特に限定されない。上記還元剤を使用する場合は、光及び／又は熱を加えて還元反応を促進させてもよい。 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. 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. There is no particular limitation as long as it can be reduced. When the reducing agent is used, light and / or heat may be added to promote the reduction reaction.
　上記金属塩、有機成分、溶媒及び還元剤を用いて、有機物で被覆された銀微粒子を調製する具体的な方法としては、例えば、上記金属塩を有機溶媒（例えばトルエン等）に溶かして金属塩溶液を調製し、当該金属塩溶液に保護分散剤としての短鎖アミンや酸価をもつ保護分散剤を添加し、ついで、ここに還元剤が溶解した溶液を徐々に滴下する方法等が挙げられる。 As a specific method for preparing silver fine particles coated with an organic substance using the above metal salt, 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. Examples include a method of preparing a solution, adding a short-chain amine as a protective dispersant or a protective dispersant having an acid value to the metal salt solution, and then gradually dropping a solution in which the reducing agent is dissolved. .
　上記のようにして得られた短鎖アミンや酸価をもつ保護分散剤で被覆された銀微粒子を含む分散液には、銀微粒子の他に、金属塩の対イオン、還元剤の残留物や分散剤が存在しており、液全体の電解質濃度や有機物濃度が高い傾向にある。このような状態の液は、電導度が高い等の理由で金属粒子の凝析が起こり、沈殿し易い。あるいは、沈殿しなくても、金属塩の対イオン、還元剤の残留物、又は分散に必要な量以上の過剰な分散剤が残留していると、導電性を悪化させるおそれがある。そこで、上記銀微粒子を含む溶液を洗浄して余分な残留物を取り除くことにより、有機物で被覆された銀微粒子を確実に得ることができる。 In the dispersion containing silver fine particles coated with the short-chain amine and the protective dispersant having an acid value obtained as described above, in addition to the silver fine particles, a metal ion counter ion, a reducing agent residue, There is a dispersant, and the concentration of the electrolyte and the organic matter in 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. Alternatively, even if precipitation does not occur, 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.
　上記洗浄方法としては、例えば、有機成分で被覆された銀微粒子を含む分散液を一定時間静置し、生じた上澄み液を取り除いた上で、銀微粒子を沈殿させる溶媒（例えば、水、メタノール、メタノール/水混合溶媒等）を加えて再度撹枠し、更に一定期間静置して生じた上澄み液を取り除く工程を幾度か繰り返す方法、上記の静置の代わりに遠心分離を行う方法、限外濾過装置やイオン交換装置等により脱塩する方法等が挙げられる。このような洗浄によって余分な残留物を取り除くと共に有機溶媒を除去することにより、本実施形態の「短鎖アミンや酸価をもつ分散剤」で被覆された金属粒子を得ることができる。 As the 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 method 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 excess residues and removing the organic solvent by such washing, metal particles coated with the “short-chain amine or the dispersant having an acid value” of the present embodiment can be obtained.
　本実施形態のうち、銀微粒子分散体（銀コロイド分散液）は、上記において得た短鎖アミンや酸価をもつ保護分散剤で被覆された銀微粒子と、上記本実施形態で説明した分散媒と、を混合することにより得られる。かかる「短鎖アミンや酸価をもつ保護分散剤」で被覆された金属粒子と分散媒との混合方法は特に限定されるものではなく、攪拌機やスターラー等を用いて従来公知の方法によって行うことができる。スパチュラのようなもので撹拌したりして、適当な出力の超音波ホモジナイザーを当ててもよい。 Among the present embodiments, the silver fine particle dispersion (silver colloid dispersion) includes the silver fine particles coated with the short-chain amine obtained above and a protective dispersant having an acid value, and the dispersion medium described in the present embodiment. And are mixed. The mixing method of the metal particles coated with the “short-chain amine or the protective dispersant having an acid value” and the dispersion medium is not particularly limited, and may be performed by a conventionally known method using a stirrer or a stirrer. Can do. An ultrasonic homogenizer with an appropriate output may be applied by stirring with a spatula or the like.
　複数の金属を含む銀微粒子分散体を得る場合、その製造方法としては特に限定されず、例えば、銀とその他の金属とからなる銀微粒子分散体を製造する場合には、上記の有機物で被覆された金属粒子の調製において、銀微粒子を含む分散液と、その他の金属粒子を含む分散液とを別々に製造し、その後混合してもよく、銀イオン溶液とその他の金属イオン溶液とを混合し、その後に還元してもよい。 When obtaining a silver fine particle dispersion containing a plurality of metals, the production method is not particularly limited. For example, when producing a silver fine particle dispersion composed of silver and other metals, the silver fine particle dispersion is coated with the organic substance. In the preparation of metal particles, a dispersion containing silver fine particles and a dispersion containing other metal particles may be produced separately and then mixed, or a silver ion solution and other metal ion solution may be mixed. Thereafter, reduction may be performed.
　還元により分解して金属銀を生成しうる銀化合物と、分配係数ｌｏｇＰが－１．０～１．４である短鎖アミンと、の混合液を調整する第１工程と、当該混合液中の前記銀化合物を還元することで表面の少なくとも一部に炭素数が５以下である短鎖アミンが付着した銀微粒子を生成する第２工程により、銀微粒子を製造してもよい。 A first step of adjusting a mixed solution of a silver compound that can be decomposed by reduction to form metallic silver and a short-chain amine having a partition coefficient log P of −1.0 to 1.4; Silver fine particles may be produced by the second step of producing silver fine particles in which a short-chain amine having 5 or less carbon atoms is attached to at least a part of the surface by reducing the silver compound.
　例えば、銀を含むシュウ酸銀等の金属化合物と短鎖アミンから生成される錯化合物を加熱して、当該錯化合物に含まれるシュウ酸イオン等の金属化合物を分解して生成する原子状の銀を凝集させることにより、短鎖アミンの保護膜に保護された銀粒子を製造することができる。 For example, atomic silver produced by heating a complex compound generated from a metal compound such as silver oxalate containing silver and a short-chain amine and decomposing the metal compound such as oxalate ion contained in the complex compound By agglomerating, silver particles protected by a short-chain amine protective film can be produced.
　このように、金属化合物の錯化合物をアミンの存在下で熱分解することで、アミンにより被覆された金属粒子を製造する金属アミン錯体分解法においては、単一種の分子である金属アミン錯体の分解反応により原子状金属が生成するため、反応系内に均一に原子状金属を生成することが可能であり、複数の成分間の反応により金属原子を生成する場合に比較して、反応を構成する成分の組成揺らぎに起因する反応の不均一が抑制され、特に工業的規模で多量の金属粉末を製造する際に有利である。 Thus, in the metal amine complex decomposition method for producing metal particles coated with amine by thermally decomposing a complex compound of a metal compound in the presence of amine, decomposition of the metal amine complex which is a single kind of molecule is performed. Since the atomic metal is generated by the reaction, it is possible to generate the atomic metal uniformly in the reaction system, and the reaction is configured as compared with the case where the metal atom is generated by the 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 metal powder is produced on an industrial scale.
　また、金属アミン錯体分解法においては、生成する金属原子に短鎖アミン分子が配位結合しており、当該金属原子に配位した短鎖アミン分子の働きにより凝集を生じる際の金属原子の運動がコントロールされるものと推察される。この結果として、金属アミン錯体分解法によれば非常に微細で、粒度分布が狭い金属粒子を製造することが可能となる。 In the metal amine complex decomposition method, a short chain amine molecule is coordinated to the metal atom to be generated, and the movement of the metal atom when aggregation occurs due to the action of the short chain amine molecule coordinated to the metal atom. Is assumed to be controlled. As a result, according to the metal amine complex decomposition method, it is possible to produce metal particles that are very fine and have a narrow particle size distribution.
　更に、製造される金属微粒子の表面にも多数の短鎖アミン分子が比較的弱い力の配位結合を生じており、これらが金属粒子の表面に緻密な保護被膜を形成するため、保存安定性に優れる表面の清浄な被覆金属粒子を製造することが可能となる。また、当該被膜を形成する短鎖アミン分子は加熱等により容易に脱離可能であるため、非常に低温で焼結可能な金属粒子を製造することが可能となる。 In addition, many short-chain amine molecules also form a relatively weak coordination bond on the surface of the metal fine particles to be produced, and these form a dense protective film on the surface of the metal particles. It is possible to produce coated metal particles having a clean surface with excellent surface resistance. In addition, since the short-chain amine molecules forming the coating can be easily detached by heating or the like, it is possible to produce metal particles that can be sintered at a very low temperature.
　また、固体状の金属化合物とアミンを混合して錯化合物等の複合化合物が生成する際に、被覆銀粒子の被膜を構成する酸価をもつ分散剤に対して、炭素数が５以下である短鎖アミンを混合して用いることにより、錯化合物等の複合化合物の生成が容易になり、短時間の混合で複合化合物を製造可能となる。また、当該短鎖アミンを混合して用いることにより、各種の用途に応じた特性を有する被覆銀粒子の製造が可能である。 In addition, when a solid metal compound and an amine are mixed to form a complex compound such as a complex compound, the number of carbon atoms is 5 or less with respect to the dispersant having an acid value constituting the coating of the coated silver particles. By mixing and using a short-chain amine, it becomes easy to produce a complex compound such as a complex compound, and the complex compound can be produced by mixing in a short time. Further, by mixing and using the short chain amine, it is possible to produce coated silver particles having characteristics according to various uses.
（３）導電膜パターン（導電膜パターン付基材）及びその製造方法
　本実施形態の転写印刷用導電性インクを用いれば、上記転写印刷用導電性インクを基材に塗布する導電性インク塗布工程と、前記基材に塗布した前記転写印刷用導電性インクを２００℃以下の温度（好ましくは１８０℃未満、更に好ましくは１５０℃以下）で焼成して導電膜パターンを形成する導電膜パターン形成工程と、により、基材と、前記基材の表面の少なくとも一部に形成される導電膜パターンと、を含む導電膜パターン付基板を製造することができる。 (3) Conductive ink coating step (coating substrate with conductive film pattern) and method for producing the same When using the conductive ink for transfer printing according to the present embodiment, the conductive ink applying step for applying the conductive ink for transfer printing to the base material. And a conductive film pattern forming step in which the conductive ink for transfer printing applied to the substrate is baked at a temperature of 200 ° C. or lower (preferably less than 180 ° C., more preferably 150 ° C. or lower) to form a conductive film pattern. Thus, a substrate with a conductive film pattern including a base material and a conductive film pattern formed on at least a part of the surface of the base material can be manufactured.
　本発明者は、鋭意検討を重ねた結果、前記転写印刷用導電性インク塗布工程での導電性インクとして、上述した本実施形態の転写印刷用導電性インクを用いれば、導電膜パターン形成工程において、前記基材に塗布した前記導電性インクを２００℃以下での温度で焼成しても、優れた導電性を有する導電膜パターンが確実に得られることを見出した。 As a result of intensive studies, the inventor used the conductive ink for transfer printing according to the present embodiment described above as the conductive ink in the conductive ink application process for transfer printing. It has been found that even when the conductive ink applied to the substrate is baked at a temperature of 200 ° C. or less, a conductive film pattern having excellent conductivity can be obtained with certainty.
　転写印刷法のうちの反転印刷法においては、まず、ブランケット上に転写印刷用導電性インクを塗布して導電性インク塗布面を形成する。ブランケットとしては、シリコーンからなるシリコーンブランケットが好ましい。ブランケットの表面に導電性インク塗布面を形成した後、所定時間放置することにより、低沸点溶剤が揮発およびブランケット中に吸収されることにより転写印刷用導電性インクの粘度が上昇する。 In the reverse printing method of the transfer printing method, first, a conductive ink application surface is formed by applying conductive ink for transfer printing on a blanket. As the blanket, a silicone blanket made of silicone is preferable. By forming the conductive ink application surface on the surface of the blanket and leaving it for a predetermined time, the low boiling point solvent is volatilized and absorbed in the blanket, thereby increasing the viscosity of the conductive ink for transfer printing.
　上記導電性インク塗布面に所定のパターンに応じた版が形成された凸版を押圧すると、当該凸版に接触する部分の導電性インクがブランケット上から除去される。このとき、導電性インクが適度な凝集性を有することにより、導電性インクが構造破壊すること無しにブランケットからの剥離と、凸版への付着とが確実に行われ、ブランケットへの望ましくない残留が抑制される。この結果、ブランケット上に残った導電性インクにより、凸版のパターンに応じた導電性インクのパターンがブランケット上に形成される。 When a relief plate having a plate corresponding to a predetermined pattern is pressed on the conductive ink application surface, the portion of the conductive ink that contacts the relief plate is removed from the blanket. At this time, since the conductive ink has an appropriate cohesiveness, the conductive ink is surely peeled off from the blanket and adhered to the relief plate without structural destruction, and undesirable residue on the blanket is prevented. It is suppressed. As a result, the conductive ink remaining on the blanket forms a conductive ink pattern corresponding to the relief pattern on the blanket.
　ブランケット上に残ったウェット状態もしくは半乾燥状態の導電性インクを、被印刷体に転写する。この際、導電性インクが適度な凝集性を有することにより、ブランケットからの剥離と、被印刷体への付着とが確実に行われ、ブランケットへの望ましくない残留が抑制される。この結果、被印刷体には、凸版に形成されたパターンに対して反転したパターンにより導電膜パターンが形成される。 Transfer the wet or semi-dried conductive ink remaining on the blanket to the substrate. At this time, since the conductive ink has appropriate cohesiveness, peeling from the blanket and adhesion to the printing medium are surely performed, and undesirable residue on the blanket is suppressed. As a result, a conductive film pattern is formed on the substrate to be printed by a pattern inverted with respect to the pattern formed on the relief plate.
　本実施形態において用いることのできる基材としては、導電性インクを塗布して加熱により焼成して導電膜パターンを搭載することのできる、少なくとも１つの主面を有するものであれば、特に制限はないが、耐熱性に優れた基材であるのが好ましい。また、先に述べたように、本実施形態の転写印刷用導電性インクは、従来の導電性インクに比較して低い温度で加熱して焼成しても十分な導電性を有する導電膜パターンを得ることができるため、この低い焼成温度よりも高い温度範囲で、従来よりも耐熱温度の低い基材を用いることが可能である。 The substrate that can be used in the present embodiment is not particularly limited as long as it has at least one main surface on which a conductive ink can be applied and fired by heating to mount a conductive film pattern. Although it is not, it is preferable that it is a base material excellent in heat resistance. In addition, as described above, the conductive ink for transfer printing of this embodiment has a conductive film pattern that has sufficient conductivity even when heated and baked at a lower temperature than conventional conductive inks. Since it can be obtained, it is possible to use a substrate having a lower heat-resistant temperature than the conventional one in a temperature range higher than this low firing temperature.
　このような基材を構成する材料としては、例えば、ポリアミド（ＰＡ）、ポリイミド（ＰＩ）、ポリアミドイミド（ＰＡＩ）、ポリエチレンテレフタレート（ＰＥＴ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリエチレンナフタレート（ＰＥＮ）等のポリエステル、ポリカーボネート（ＰＣ）、ポリエーテルスルホン（ＰＥＳ）、ビニル樹脂、フッ素樹脂、液晶ポリマー、セラミックス、ガラス又は金属等を挙げることができる。また、基材は、例えば板状又はストリップ状等の種々の形状であってよく、リジッドでもフレキシブルでもよい。基材の厚さも適宜選択することができる。接着性若しくは密着性の向上又はその他の目的ために、表面層が形成された基材や親水化処理等の表面処理を施した基材を用いてもよい。 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. Further, 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.
　上記のように塗布した後の塗膜を、２００℃以下（好ましくは１８０℃未満、更に好ましくは１５０℃以下）の温度に加熱することにより焼成し、本実施形態の導電膜パターン（導電膜パターン付基材）を得ることができる。 The coated film after coating as described above is baked by heating to a temperature of 200 ° C. or less (preferably less than 180 ° C., more preferably 150 ° C. or less), and the conductive film pattern (conductive film pattern) of this embodiment. Substrate) can be obtained.
　上記焼成を行う方法は特に限定されるものではなく、例えば従来公知のギアオーブン等を用いて、基材上に塗布または描画した上記導電性インクの温度が２００℃以下（好ましくは１８０℃未満、更に好ましくは１５０℃以下）となるように焼成することによって導電膜パターンを形成することができる。上記焼成の温度の下限は必ずしも限定されず、基材上に導電膜パターンを形成できる温度であって、かつ、本発明の効果を損なわない範囲で上記有機成分等を蒸発又は分解により除去できる温度であることが好ましい（本発明の効果を損なわない範囲で一部が残存していてもよいが、望ましくは全て除去されるのが好ましい。）。 The method for performing the baking is not particularly limited. For example, the temperature of the conductive ink applied or drawn on the substrate using a conventionally known gear oven or the like is 200 ° C. or less (preferably less than 180 ° C., More preferably, the conductive film pattern can be formed by baking to 150 ° C. or lower. The lower limit of the firing temperature is not necessarily limited, and is a temperature at which a conductive film pattern can be formed on a substrate, and a temperature at which the organic components and the like can be removed by evaporation or decomposition within a range that does not impair 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).
　本実施形態の導電性インクによれば、１２０℃程度の低温加熱処理でも高い導電性を発現する導電膜パターンを形成することができるため、比較的熱に弱い基材上にも導電膜パターンを形成することができる。また、焼成時間は特に限定されるものではなく、焼成温度に応じて、基材上に導電膜パターンを形成できる。 According to the conductive ink of the present embodiment, a conductive film pattern exhibiting high conductivity can be formed even by a low-temperature heat treatment at about 120 ° C. Therefore, the conductive film pattern is also formed on a relatively heat-sensitive substrate. Can be formed. Moreover, baking time is not specifically limited, A conductive film pattern can be formed on a base material according to baking temperature.
　本実施形態においては、上記基材と導電膜パターンとの密着性を更に高めるため、上記基材の表面処理を行ってもよい。上記表面処理方法としては、例えば、コロナ処理、プラズマ処理、ＵＶ処理、電子線処理等のドライ処理を行う方法、基材上にあらかじめプライマー層や導電性インク受容層を設ける方法等が挙げられる。 In this embodiment, in order to further improve the adhesion between the substrate and the conductive film pattern, the substrate may be subjected to a surface treatment. Examples of the surface treatment method include a method of performing a dry treatment such as a corona treatment, a plasma treatment, a UV treatment, and an electron beam treatment, and a method of previously providing a primer layer and a conductive ink receiving layer on a substrate.
　このようにして本実施形態の導電膜パターン（導電膜パターン付基材）を得ることができる。このようにして得られる本実施形態の導電膜パターンは、例えば、０．１～５μｍ程度、より好ましくは０．１～１μｍである。本実施形態の導電性インクを用いれば、厚さが０．１～５μｍ程度であっても、十分な導電性を有する導電膜パターンが得られる。なお、本実施形態の導電膜パターンの体積抵抗値は、１５μΩ・ｃｍ以下である。 Thus, the conductive film pattern (substrate with conductive film pattern) of this embodiment can be obtained. The conductive film pattern of the present embodiment thus obtained is, for example, about 0.1 to 5 μm, more preferably 0.1 to 1 μm. When the conductive ink of this embodiment is used, a conductive film pattern having sufficient conductivity can be obtained even when the thickness is about 0.1 to 5 μm. In addition, the volume resistance value of the electrically conductive film pattern of this embodiment is 15 microhm * cm or less.
　なお、本実施形態の導電膜パターンの厚みｔは、例えば、下記式を用いて求めることはできる（導電膜パターンの厚さｔは、レーザー顕微鏡（例えば、キーエンス製レーザー顕微鏡ＶＫ－９５１０）で測定することも可能である。）。
　　　式：ｔ＝ｍ／（ｄ×Ｍ×ｗ）
　　ｍ：導電膜パターン重量（スライドガラス上に形成した導電膜パターンの重さを電子天秤で測定）
　　ｄ：導電膜パターン密度（ｇ／ｃｍ3）（銀の場合は１０．５ｇ／ｃｍ3）
　　Ｍ：導電膜パターン長（ｃｍ）（スライドガラス上に形成した導電膜パターンの長さをＪＩＳ１級相当のスケールで測定）
　　ｗ：導電膜パターン幅（ｃｍ）（スライドガラス上に形成した導電膜パターンの幅をＪＩＳ１級相当のスケールで測定） In addition, the thickness t of the conductive film pattern of the present embodiment can be obtained using, for example, the following formula (the thickness t of the conductive film pattern is measured with a laser microscope (for example, a laser microscope VK-9510 manufactured by Keyence). It is also possible to do this.)
Formula: t = m / (d × M × w)
m: conductive film pattern weight (the weight of the conductive film pattern formed on the slide glass is measured with an electronic balance)
d: Conductive film pattern density (g / cm 3 ) (10.5 g / cm 3 in the case of silver)
M: conductive film pattern length (cm) (the length of the conductive film pattern formed on the slide glass is measured on a scale equivalent to JIS class 1)
w: Conductive film pattern width (cm) (The width of the conductive film pattern formed on the slide glass is measured on a scale equivalent to JIS class 1)
　以下、実施例及び比較例を挙げて本発明の転写印刷用導電性インク及び当該導電性インクを用いた導電膜パターン（導電膜パターン付基材）の製造方法について更に説明するが、本発明はこれらの実施例に何ら限定されるものではない。 Hereinafter, the conductive ink for transfer printing of the present invention and a method for producing a conductive film pattern (substrate with a conductive film pattern) using the conductive ink will be further described with reference to Examples and Comparative Examples. The present invention is not limited to these examples.
≪調製例１≫
　３－メトキシプロピルアミン（和光純薬工業（株）製試薬一級、炭素数：４、ｌｏｇＰ：－０．５）８．９ｇと、高分子分散剤であるＤＩＳＰＥＲＢＹＫ－１１１を０．３ｇとを混合し、マグネティックスターラーにてよく撹拌し、アミン混合液を生成した（添加したアミンのモル比は銀に対して１０）。次いで、撹拌を行いながら、シュウ酸銀３．０ｇを添加した。シュウ酸銀の添加後、室温で撹拌を続けることにより、シュウ酸銀を粘性のある白色の物質へと変化させ、当該変化が外見的に終了したことを目視により確認し、その時点で撹拌を終了した（第１前工程）。
　得られた混合液をオイルバスに移し、１２０℃で加熱撹拌した。撹拌の開始直後に二酸化炭素の発生を伴う反応が開始し、その後、二酸化炭素の発生が完了するまで撹拌を行うことで、銀微粒子がアミン混合液中に懸濁した懸濁液を得た（第２前工程）。
　次に、得られた懸濁液の分散媒を置換するため、メタノール／水の混合溶媒１０ｍＬを加えて撹拌した後、遠心分離により銀微粒子を沈降させて分離した。分離した銀微粒子に対して、再度、メタノール／水の混合溶媒１０ｍＬを加えて撹拌した後、遠心分離により銀微粒子を沈降させて分離し、分散溶媒としてエタノール／イソブタノール／イソプロピルアルコール（４０：４０：２０ ｖ／ｖ）混合溶媒２．１ｇを加えることで、固形分濃度４８質量％の銀微粒子分散体Ａを得た。 << Preparation Example 1 >>
8.9 g of 3-methoxypropylamine (Wako Pure Chemical Industries, Ltd., first grade reagent, carbon number: 4, log P: -0.5) and 0.3 g of DISPERBYK-111, a polymer dispersant, are mixed. Then, the mixture was thoroughly stirred with a magnetic stirrer to produce an amine mixture (molar ratio of added amine was 10 with respect to silver). Next, 3.0 g of silver oxalate was added while stirring. After the addition of silver oxalate, by continuing stirring at room temperature, the silver oxalate was changed to a viscous white substance, and it was visually confirmed that the change was apparently observed. Finished (first pre-process).
The resulting mixture was transferred to an oil bath and heated and stirred at 120 ° C. The reaction with the generation of carbon dioxide started immediately after the start of stirring, 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 ( Second pre-process).
Next, in order to replace the dispersion medium of the obtained suspension, 10 mL of a mixed solvent of methanol / water was added and stirred, and then silver fine particles were precipitated and separated by centrifugation. To the separated silver fine particles, 10 mL of a mixed solvent of methanol / water was added and stirred again, and then the fine silver particles were separated by centrifugation and separated, and ethanol / isobutanol / isopropyl alcohol (40:40) was used as a dispersion solvent. : 20 v / v) By adding 2.1 g of a mixed solvent, a silver fine particle dispersion A having a solid content of 48% by mass was obtained.
≪調製例２≫
　３－メトキシプロピルアミン（和光純薬工業（株）製試薬一級、炭素数：４、ｌｏｇＰ：－０．５）８．９ｇと、高分子分散剤であるＤＩＳＰＥＲＢＹＫ－１０２を０．３ｇとを混合し、マグネティックスターラーにてよく撹拌し、アミン混合液を生成した（添加したアミンのモル比は銀に対して５）。次いで、撹拌を行いながら、シュウ酸銀３．０ｇを添加した。シュウ酸銀の添加後、室温で撹拌を続けることにより、シュウ酸銀を粘性のある白色の物質へと変化させ、当該変化が外見的に終了したことを目視により確認し、その時点で撹拌を終了した（第１前工程）。
　得られた混合液をオイルバスに移し、１２０℃で加熱撹拌した。撹拌の開始直後に二酸化炭素の発生を伴う反応が開始し、その後、二酸化炭素の発生が完了するまで撹拌を行うことで、銀微粒子がアミン混合液中に懸濁した懸濁液を得た（第２前工程）。
　次に、得られた懸濁液の分散媒を置換するため、メタノール／水の混合溶媒１０ｍＬを加えて撹拌した後、遠心分離により銀微粒子を沈降させて分離した。分離した銀微粒子に対して、再度、メタノール／水の混合溶媒１０ｍＬを加えて撹拌した後、遠心分離により銀微粒子を沈降させて分離し、ＳＯＬＳＰＥＲＳＥ４１０００（日本ルーブリゾール（株）製）０．０６ｇを含むエタノール２．１ｇを加えることで、固形分濃度４８質量％の銀微粒子分散体Ｂを得た。 << Preparation Example 2 >>
8.9 g of 3-methoxypropylamine (Wako Pure Chemical Industries, Ltd., first grade reagent, carbon number: 4, log P: -0.5) and 0.3 g of DISPERBYK-102, a polymer dispersant, are mixed. Then, the mixture was thoroughly stirred with a magnetic stirrer to produce an amine mixture (molar ratio of added amine was 5 with respect to silver). Next, 3.0 g of silver oxalate was added while stirring. After the addition of silver oxalate, by continuing stirring at room temperature, the silver oxalate was changed to a viscous white substance, and it was visually confirmed that the change was apparently observed. Finished (first pre-process).
The resulting mixture was transferred to an oil bath and heated and stirred at 120 ° C. The reaction with the generation of carbon dioxide started immediately after the start of stirring, 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 ( Second pre-process).
Next, in order to replace the dispersion medium of the obtained suspension, 10 mL of a mixed solvent of methanol / water was added and stirred, and then silver fine particles were precipitated and separated by centrifugation. To the separated silver fine particles, 10 mL of a mixed solvent of methanol / water was added and stirred again, and then the silver fine particles were settled and separated by centrifugation. By adding 2.1 g of ethanol, a silver fine particle dispersion B having a solid content concentration of 48% by mass was obtained.
≪実施例及び比較例≫
　上記のようにして得た銀微粒子分散体Ａ又はＢを用い、表１に示すその他の成分と混合し、実施例１～７実施転写印刷用導電性インク１～７及び比較例１～３の比較転写印刷用導電性インク１～３を調製した。なお表１における成分の量の単位は「質量％」とした。
　また、上記の銀微粒子分散体Ａ及びＢ並びに実施転写印刷用導電性インク１～７及び比較転写印刷用導電性インク１～３について、以下の評価試験を実施した。その結果を表１に示した。 << Examples and Comparative Examples >>
Using the silver fine particle dispersion A or B obtained as described above, it was mixed with the other components shown in Table 1, and Examples 1 to 7 of the conductive inks 1 to 7 for transfer printing and Comparative Examples 1 to 3 were used. Conductive inks 1 to 3 for comparative transfer printing were prepared. The unit of the amount of the component in Table 1 was “mass%”.
In addition, the following evaluation tests were performed on the above-described silver fine particle dispersions A and B, the conductive inks 1 to 7 for the transfer printing, and the conductive inks 1 to 3 for the comparative transfer printing. The results are shown in Table 1.
［評価試験］
（１）有機分測定
　銀微粒子分散体に含まれる有機成分の含有量を、熱重量分析法で測定した。具体的には、銀微粒子分散体の固形分を１０℃／分の昇温速度で加熱し、室温～５００℃の重量減少量として有機成分の含有量を特定した。
（２）分散性
　転写印刷用導電性インクを容器中に静置し、室温１日後、沈殿の有無及び上澄みの状態を目視で観察することにより、銀微粒子分散体の分散性を評価した。容器下に沈降物がほとんど認められない場合を「○」、沈降物が少量認められた場合を「△」、容器上下で明らかに濃度差があり、沈降物がはっきり認められる場合を「×」と評価した。
（３）導電性インクの表面張力測定
　実施例１～４で得られた実施転写印刷用導電性インク１～４、及び比較例１～３で得られた比較転写印刷用導電性インク１～３の表面張力を、全自動表面張力計ＣＢＶＰ－Ｚ（協和界面科学（株）製）により測定した。測定には白金プレートを用い、自動測定で行った。測定温度は常温（２０～２５℃）とした。
（４）導電性インクの濡れ性評価
　実施例１～７で得られた実施転写印刷用導電性インク１～７、及び比較例１～３で得られた比較転写印刷用導電性インク１～３を用い、シリコーン製ブランケット上にバーコーター（Ｎｏ．７）で塗布し、ブランケットに対する転写印刷用導電性インクの濡れ性を目視評価した。濡れ性が良好な場合は「○」、不良な場合は「×」と評価した。
（５）印刷形状（細線描画性）の評価
　転写印刷用導電性インクを塗布したブランケット上にガラス凸版を押圧し、非画像部（不要部分）を転写して除去した。更に、ブランケット材に基材（ＰＥＮ：ポリエチレンナフタレート）を押圧することでパターンを基材に転写した。得られたパターン形状を目視観察することで、印刷形状を評価した。印刷形状が良好な場合は「○」、許容範囲の場合は「△」、不良の場合は「×」と評価し。パターンは細線とし、ライン幅１０、２０、３０、５０、１００μｍ、長さ１０ｍｍとした。
（６）転写性の評価
　上記（５）で形成した印刷形状、及びブランケット上に残った導電性インクを目視評価することによって転写性を評価した。印刷形状が良好で、ブランケット上にほぼ残っていない場合は「○」、許容範囲の場合は「△」、印刷形状が悪いか、もしくはブランケット上に明らかに残っている場合は「×」とした。
（７）連続印刷性の評価
　上記（５）の印刷形状の評価の層さを連続５回繰り返すことにより、連続印刷性を評価した。
（８）導電膜パターンの導電性評価
　基材に転写されたパターン（ライン幅１００μｍ、長さ１０ｍｍ）を１２０℃×３０分間の条件で焼成し、パターンの抵抗値を測定した。具体的には、横川メータ＆インスツルメンツ（株）製の携帯用ダブルブリッジ２７６９を用いてダブルブリッジ法により体積抵抗率を求めた。以下の式に基づき、測定端子間距離と導電膜パターンの厚みから体積抵抗値を換算した。
　　　式：（体積抵抗率ρｖ）＝
　　　　（抵抗値Ｒ）×（被膜幅ｗ）×（被膜厚さｔ）／（端子間距離Ｌ） [Evaluation test]
(1) Organic content measurement The content of organic components contained in the silver fine particle dispersion was measured by thermogravimetric analysis. Specifically, the solid content of the silver fine particle dispersion was heated at a heating rate of 10 ° C./min, and the content of the organic component was specified as the weight loss from room temperature to 500 ° C.
(2) Dispersibility The conductive ink for transfer printing was allowed to stand in a container, and after 1 day at room temperature, the presence or absence of precipitation and the state of the supernatant were visually observed to evaluate the dispersibility of the silver fine particle dispersion. “○” when almost no sediment is observed under the container, “△” when a small amount of sediment is observed, and “×” when there is a clear difference in concentration between the top and bottom of the container and sediment is clearly observed. It was evaluated.
(3) Measurement of surface tension of conductive ink Conductive transfer printing conductive inks 1 to 4 obtained in Examples 1 to 4 and Comparative transfer printing conductive inks 1 to 3 obtained in Comparative Examples 1 to 3 The surface tension was measured with a fully automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.). The measurement was performed by automatic measurement using a platinum plate. The measurement temperature was room temperature (20 to 25 ° C.).
(4) Conductive ink wettability evaluation Conductive transfer printing conductive inks 1 to 7 obtained in Examples 1 to 7 and Comparative transfer printing conductive inks 1 to 3 obtained in Comparative Examples 1 to 3 Was applied on a silicone blanket with a bar coater (No. 7), and the wettability of the conductive ink for transfer printing to the blanket was visually evaluated. When the wettability was good, it was evaluated as “◯”, and when it was poor, it was evaluated as “x”.
(5) Evaluation of printing shape (thin line drawing property) A glass relief was pressed on a blanket coated with conductive ink for transfer printing, and a non-image part (unnecessary part) was transferred and removed. Furthermore, the pattern was transferred to the base material by pressing the base material (PEN: polyethylene naphthalate) against the blanket material. The printed shape was evaluated by visually observing the obtained pattern shape. Evaluate as “◯” when the printed shape is good, “△” when it is acceptable, and “x” when it is defective. The pattern was a thin line, and the line width was 10, 20, 30, 50, 100 μm and the length was 10 mm.
(6) Evaluation of transferability Transferability was evaluated by visually evaluating the printed shape formed in (5) above and the conductive ink remaining on the blanket. “○” if the printed shape is good and almost not left on the blanket, “△” if it is acceptable, or “x” if the printed shape is bad or clearly left on the blanket .
(7) Evaluation of continuous printability Continuous printability was evaluated by repeating the layer of the printed shape evaluation of (5) above five times continuously.
(8) Conductivity evaluation of conductive film pattern The pattern transferred to the substrate (line width 100 μm, length 10 mm) was baked under the conditions of 120 ° C. × 30 minutes, and the resistance value of the pattern was measured. Specifically, the volume resistivity was determined by the double bridge method using a portable double bridge 2769 manufactured by Yokogawa Meter & Instruments Co., Ltd. Based on the following formula, the volume resistance value was converted from the distance between the measurement terminals and the thickness of the conductive film pattern.
Formula: (volume resistivity ρv) =
(Resistance value R) × (film width w) × (film thickness t) / (terminal distance L)
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　なお、表１中、「Novec7300」住友３Ｍ製であり、「サーフロンＳ－６５１」はＡＧＣ製ケミカル製である。また、「フタージェント６１０ＦＭ」はネオス社製である。 In Table 1, “Novec7300” is manufactured by Sumitomo 3M, and “Surflon S-651” is manufactured by AGC Chemical. “Factent 610FM” is manufactured by Neos.
　表１に示した結果から明らかなように、本発明の転写印刷用導電性インクは、分散性、濡れ性、印刷性及び導電性に優れていることわかる。なかでも、銀微粒子分散体Ｂを用いた実施例３及び４は、連続印刷性にも優れており、特に好ましい。
　これに対し、比較例１及び２により、特定の高沸点溶剤を含有しない導電性インクは転写性に劣ることがわかる。また、比較例３により、高沸点溶剤の含有量が過剰の場合は、乾燥が遅く転写性に劣ることがわかる。更に、比較例２により、フッ素溶剤のみを含む場合でも、濡れ性は確保できるが転写性に劣ることがわかる。 As is apparent from the results shown in Table 1, it can be seen that the conductive ink for transfer printing of the present invention is excellent in dispersibility, wettability, printability and conductivity. Among them, Examples 3 and 4 using the silver fine particle dispersion B are particularly preferable because they are excellent in continuous printability.
On the other hand, it can be seen from Comparative Examples 1 and 2 that the conductive ink containing no specific high boiling point solvent is inferior in transferability. Further, it can be seen from Comparative Example 3 that when the content of the high boiling point solvent is excessive, drying is slow and transferability is poor. Further, it can be seen from Comparative Example 2 that even when only the fluorine solvent is included, the wettability can be ensured but the transferability is poor.

Claims (6)

  1. 　金属粒子と、
    　エタノールを含む溶媒と、
    　水酸基を有する高沸点溶剤０．１～３．０質量％と、を含むこと、
    　を特徴とする転写印刷用導電性インク。     Metal particles,
    A solvent comprising ethanol;
    Containing 0.1 to 3.0% by mass of a high-boiling solvent having a hydroxyl group,
    Conductive ink for transfer printing, characterized by
  2. 　前記高沸点溶剤が、１，３－ブチレングリコール、２，４－ジエチル－１，５－ペンタンジオール又はオクタンジオールを含む請求項１に記載の転写印刷用導電性インク。 The conductive ink for transfer printing according to claim 1, wherein the high boiling point solvent contains 1,3-butylene glycol, 2,4-diethyl-1,5-pentanediol or octanediol.
  3. 　更にハイドロフルオロエーテルを含む請求項１又は２に記載の転写印刷用導電性インク。 The conductive ink for transfer printing according to claim 1, further comprising hydrofluoroether.
  4. 　前記金属粒子が銀微粒子であり、
    　銀微粒子と、
    　炭素数が５以下であり分配係数ｌｏｇＰが－１．０～１．４である短鎖アミンと、
    　高極性溶媒と、
    　前記銀微粒子を分散させるための酸価を有する分散剤と、
    を含む銀微粒子分散体を含むこと、
    　を特徴とする請求項１～３のうちのいずれかに記載の転写印刷用導電性インク。     The metal particles are silver particles;
    Silver particles,
    A short-chain amine having 5 or less carbon atoms and a partition coefficient log P of -1.0 to 1.4,
    A highly polar solvent;
    A dispersant having an acid value for dispersing the silver fine particles;
    A silver fine particle dispersion containing
    The conductive ink for transfer printing according to any one of claims 1 to 3.
  5. 　前記銀微粒子分散体において、前記短鎖アミンがアルコキシアミンであり、更に、酸価を有する保護分散剤を含むこと、
    　を特徴とする請求項４に記載の転写印刷用導電性インク。     In the silver fine particle dispersion, the short chain amine is an alkoxyamine, and further contains a protective dispersant having an acid value.
    The conductive ink for transfer printing according to claim 4.
  6. 　前記保護分散剤の酸価が５～２００であり、リン酸由来の官能基を有すること、
    　を特徴とする請求項５に記載の転写印刷用導電性インク。     The protective dispersant has an acid value of 5 to 200, and has a functional group derived from phosphoric acid,
    The conductive ink for transfer printing according to claim 5.
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