WO2023033163A1 - Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor - Google Patents

Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor Download PDF

Info

Publication number
WO2023033163A1
WO2023033163A1 PCT/JP2022/033197 JP2022033197W WO2023033163A1 WO 2023033163 A1 WO2023033163 A1 WO 2023033163A1 JP 2022033197 W JP2022033197 W JP 2022033197W WO 2023033163 A1 WO2023033163 A1 WO 2023033163A1
Authority
WO
WIPO (PCT)
Prior art keywords
conductive paste
gravure printing
dispersant
mass
less
Prior art date
Application number
PCT/JP2022/033197
Other languages
French (fr)
Japanese (ja)
Inventor
健二 福田
尚史 吉田
純平 山田
清 高野
徹 安藤
卓哉 河村
Original Assignee
住友金属鉱山株式会社
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 住友金属鉱山株式会社 filed Critical 住友金属鉱山株式会社
Priority to KR1020247008662A priority Critical patent/KR20240049576A/en
Priority to CN202280059331.5A priority patent/CN117897781A/en
Publication of WO2023033163A1 publication Critical patent/WO2023033163A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/30—Stacked capacitors

Definitions

  • the present invention relates to a conductive paste for gravure printing, electronic components, and laminated ceramic capacitors.
  • Multilayer ceramic capacitors have a structure in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated. By thinning these dielectric layers and internal electrode layers, miniaturization and high capacity can be achieved. can be planned.
  • a laminated ceramic capacitor is manufactured, for example, as follows. First, on the surface of a dielectric green sheet containing dielectric powder such as barium titanate (BaTiO 3 ) and binder resin, an internal electrode paste (conductive paste) is printed in a predetermined electrode pattern, and the dried films are stacked in multiple layers to obtain a laminate in which the dried films and the dielectric green sheets are stacked in multiple layers. Next, this laminated body is thermocompression-bonded to be integrated to form a compression-bonded body. This compressed body is cut, subjected to organic binder removal treatment in an oxidizing atmosphere or inert atmosphere, and then fired to obtain fired chips in which internal electrode layers and dielectric layers are alternately laminated. Next, an external electrode paste is applied to both ends of the fired chip, and after firing, nickel plating or the like is applied to the surfaces of the external electrodes to obtain a multilayer ceramic capacitor.
  • dielectric green sheet containing dielectric powder such as barium titanate (BaTiO 3 ) and binder resin
  • screen printing has been commonly used as a printing method for printing conductive paste on dielectric green sheets. Therefore, it is required to print a finer electrode pattern with high productivity.
  • gravure is a continuous printing method in which the conductive paste is filled into the depressions provided in the plate making, and the conductive paste is transferred from the plate by pressing it against the surface to be printed.
  • a printing method has been proposed.
  • the gravure printing method has a high printing speed and excellent productivity.
  • a conductive paste used for forming the internal conductor film in a laminated ceramic electronic component comprising a plurality of ceramic layers and an internal conductor film extending along a specific interface between the ceramic layers by gravure printing 30 to 70% by weight of a solid component containing metal powder, 1 to 10% by weight of an ethyl cellulose resin component having an ethoxy group content of 49.6% or more, and 0.05 to 5% by weight of a dispersant and a solvent component as the remainder, the viscosity ⁇ 0.1 at a shear rate of 0.1 (s -1 ) is 1 Pa s or more, and the viscosity at a shear rate of 0.02 (s -1 ) Conductive pastes are described which are thixotropic fluids with ⁇ 0.02 satisfying a specific formula.
  • Patent Document 2 a conductive paste used for forming by gravure printing in the same manner as in Patent Document 1, 30 to 70% by weight solid component containing metal powder, 1 to 10% by weight A thixotropic fluid containing a resin component, 0.05 to 5% by weight of a dispersant, and the balance of a solvent component, and having a viscosity of 1 Pa s or more at a shear rate of 0.1 (s -1 ), It describes a conductive paste having a viscosity change rate of 50% or more at a shear rate of 10 (s -1 ) based on the viscosity at a shear rate of 0.1 (s -1 ).
  • these conductive pastes are thixotropic fluids having a viscosity of 1 Pa s or more at a shear rate of 0.1 (s -1 ), and are stable at high speed in gravure printing. It is said that continuous printability can be obtained, and multilayer ceramic electronic components such as multilayer ceramic capacitors can be manufactured with good production efficiency.
  • Patent Document 3 discloses a conductive powder for internal electrodes of a multilayer ceramic capacitor containing conductive powder (A), organic resin (B), organic solvent (C), additive (D), and dielectric powder (E).
  • organic resin (B) is polyvinyl butyral with a degree of polymerization of 10000 or more and 50000 or less, and ethyl cellulose with a weight average molecular weight of 10000 or more and 100000 or less
  • the organic solvent (C) is propylene glycol monobutyl ether, Alternatively, it consists of either a mixed solvent of propylene glycol monobutyl ether and propylene glycol methyl ether acetate, or a mixed solvent of propylene glycol monobutyl ether and mineral spirits
  • the additive (D) is a gravure printing agent consisting of a separation inhibitor and a dispersant.
  • a conductive paste is described. According to Patent Document 3, this conductive paste has a viscosity suitable for gravure printing and is said to have good
  • a conductive paste for gravure printing is required to have a low viscosity.
  • a ceramic powder such as barium titanate and a conductive powder such as Ni are added, these powders.
  • the sedimentation velocity difference due to the difference in specific gravity has a more pronounced effect, and the conductive powder and the ceramic powder are easily separated.
  • a phenomenon called "whitening" may occur in which a white separation layer containing ceramic powder is generated at the top when the conductive paste is produced.
  • the conductive paste for gravure printing has a lower viscosity than the conductive paste for screen printing, etc.
  • the ratio of the viscosity after long-term storage to the viscosity immediately after production is It was found that the calculated thickening ratio over time tends to be high.
  • the appropriate viscosity range for gravure printing is narrower, and accurate viscosity control is required for the paste to be applied. There is a problem that the printing process is complicated.
  • the present invention provides a conductive paste that has a low paste viscosity suitable for gravure printing stably over a long period of time and can suppress separation between the conductive powder and the ceramic powder. intended to provide
  • a conductive paste for gravure printing containing a conductive powder, a ceramic powder, a dispersant, a binder resin and an organic solvent, wherein the dispersant is a carboxylic acid having a weight average molecular weight of 5000 or more
  • the dispersant is a carboxylic acid having a weight average molecular weight of 5000 or more
  • a conductive paste for gravure printing containing a polymer dispersant and a carboxylic acid polymer dispersant in an amount of 0.01% by mass or more and less than 2.0% by mass with respect to the entire conductive paste.
  • the acid value of the carboxylic acid polymer dispersant is preferably 50 mgKOH/g or more and 250 mgKOH/g or less.
  • the carboxylic acid-based polymer dispersant preferably contains a polymer-based dispersant having a comb structure and/or a block polymer structure. Further, it is preferable that the polymeric dispersant having a comb structure has a graft chain containing an alkylene oxide polymer.
  • the organic solvent is dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), terpineol (TPO), propylene glycol monobutyl ether (PNB), diethylene glycol monobutyl ether acetate (BCA), and the group consisting of diisobutyl ketone (DIBK) It is preferable to include one or more selected types.
  • the content of the carboxylic acid polymer dispersant may be 60% by mass or more with respect to the total amount of the dispersant.
  • the dispersant may contain a carboxylic acid-based dispersant having a molecular weight of less than 5,000 in an amount of 0% by mass or more and 60% by mass or less based on the total amount of the dispersant.
  • the conductive powder preferably contains one or more metal powders selected from Ni, Pd, Pt, Au, Ag, Cu, and alloys thereof. Also, the conductive powder preferably has an average particle size of 0.05 ⁇ m or more and 1.0 ⁇ m or less. Also, the ceramic powder preferably contains barium titanate. Also, the ceramic powder preferably has an average particle size of 0.01 ⁇ m or more and 0.5 ⁇ m or less. Moreover, it is preferable that the ceramic powder is contained in an amount of 1% by mass or more and 20% by mass or less with respect to the entire conductive paste. Moreover, it is preferable that the binder resin contains a cellulose-based resin.
  • the conductive paste for gravure printing is preferably for internal electrodes of laminated ceramic parts. Further, the conductive paste for gravure printing preferably has a viscosity of 1.2 Pa ⁇ S or less at a shear rate of 100 sec ⁇ 1 .
  • a second aspect of the present invention provides an electronic component formed using the above conductive paste for gravure printing.
  • a laminated ceramic capacitor having at least a laminated body in which a dielectric layer and an internal electrode layer are laminated, wherein the internal electrode layer is a laminated ceramic capacitor formed using the above conductive paste for gravure printing provided.
  • the conductive paste of the present invention has viscosity characteristics suitable for gravure printing, and can suppress separation between the conductive powder and the ceramic powder even in a low-viscosity paste.
  • the conductive paste of the present invention has good viscosity stability over a long period of time, so viscosity adjustment during printing becomes unnecessary, contributing to simplification of the printing process.
  • FIG. 1A and 1B are a perspective view (FIG. 1A) and a cross-sectional view (FIG. 1B) showing a laminated ceramic capacitor according to an embodiment.
  • the conductive paste of this embodiment contains conductive powder, ceramic powder, dispersant, binder resin and organic solvent. Each component will be described in detail below.
  • the conductive powder is not particularly limited, and metal powder can be used.
  • one or more powders selected from Ni, Pd, Pt, Au, Ag, Cu, and alloys thereof can be used.
  • powder of Ni or its alloy Ni alloy
  • Ni alloy Ni alloy
  • the Ni alloy for example, an alloy of Ni and at least one element selected from the group consisting of Mn, Cr, Co, Al, Fe, Cu, Zn, Ag, Au, Pt and Pd can be used. can.
  • the content of Ni in the Ni alloy is, for example, 50% by mass or more, preferably 80% by mass or more.
  • the Ni powder may contain about several hundred ppm of the element S in order to suppress sudden gas generation due to partial thermal decomposition of the binder resin during the binder removal treatment.
  • the average particle size of the conductive powder is preferably 0.05 ⁇ m or more and 1.0 ⁇ m or less, more preferably 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • the average particle size is a value obtained from observation with a scanning electron microscope (SEM), and is obtained by measuring the particle size of each of a plurality of particles from an image observed with a SEM at a magnification of 10,000. is the average value (SEM average particle size) obtained.
  • the content of the conductive powder is preferably 30% by mass or more and less than 70% by mass, more preferably 40% by mass or more and 60% by mass or less with respect to the entire conductive paste.
  • the conductivity and dispersibility are excellent.
  • the ceramic powder is not particularly limited, and for example, in the case of a paste for internal electrodes of a laminated ceramic capacitor, a known ceramic powder is appropriately selected depending on the type of laminated ceramic capacitor to be applied.
  • a perovskite-type oxide containing Ba and Ti can be used, preferably containing barium titanate (BaTiO 3 ).
  • a ceramic powder containing barium titanate as a main component and an oxide as an auxiliary component may be used.
  • the oxides include one or more oxides selected from Mn, Cr, Si, Ca, Ba, Mg, V, W, Ta, Nb and rare earth elements.
  • a ceramic powder for example, there is a perovskite-type oxide ferroelectric ceramic powder in which Ba atoms or Ti atoms of barium titanate (BaTiO 3 ) are replaced with other atoms such as Sn, Pb, Zr, or the like. mentioned.
  • the ceramic powder used in the conductive paste for the internal electrodes may have the same composition as the dielectric ceramic powder forming the green sheets of the multilayer ceramic capacitor (electronic component). As a result, the occurrence of cracks due to shrinkage mismatch at the interfaces between the dielectric layers and the internal electrode layers in the sintering process is suppressed.
  • ceramic powder include ZnO, ferrite, PZT, BaO, Al 2 O 3 , Bi 2 O 3 , R (rare earth element) 2 O 3 , in addition to the perovskite oxide containing Ba and Ti. Oxides such as TiO 2 and Nd 2 O 3 can be mentioned.
  • One type of ceramic powder may be used, or two or more types may be used.
  • the average particle size of the ceramic powder is, for example, 0.01 ⁇ m or more and 0.5 ⁇ m or less, preferably 0.01 ⁇ m or more and 0.3 ⁇ m or less. Since the average particle size of the ceramic powder is within the above range, when it is used as an internal electrode paste, sufficiently fine and thin uniform internal electrodes can be formed.
  • the average particle size is a value obtained from observation with a scanning electron microscope (SEM), and is obtained by measuring the particle size of each of a plurality of particles from an image observed with a SEM at a magnification of 50,000. is the average value (SEM average particle size) obtained.
  • the content of the ceramic powder is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, relative to the entire conductive paste. When the content of the ceramic powder is within the above range, excellent dispersibility and sinterability are obtained.
  • the content of the ceramic powder is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 3 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the conductive powder.
  • binder resin is not particularly limited, and known resins can be used.
  • binder resins include cellulose resins such as methyl cellulose, ethyl cellulose, ethylhydroxyethyl cellulose, and nitrocellulose, acrylic resins, and acetal resins including butyral resins such as polyvinyl butyral.
  • cellulose resins such as methyl cellulose, ethyl cellulose, ethylhydroxyethyl cellulose, and nitrocellulose
  • acrylic resins and acetal resins including butyral resins such as polyvinyl butyral.
  • it preferably contains a cellulose-based resin, and more preferably contains ethyl cellulose.
  • When used as an internal electrode paste it may contain an acetal resin or may be used alone from the viewpoint of improving the adhesive strength with the green sheet.
  • the binder resin may contain, for example, both a cellulose-based resin and an acetal-based resin.
  • the binder resin may contain, for example, 20% by mass or more, or 30% by mass or more of the acetal-based resin with respect to the entire binder resin.
  • the binder resin may contain 50% by mass or less of the acetal-based resin with respect to the entire binder resin.
  • the degree of polymerization and weight average molecular weight of the binder resin can be appropriately adjusted within the above ranges according to the required viscosity of the conductive paste.
  • the content of the binder resin is preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 7% by mass or less, relative to the entire conductive paste.
  • the conductivity and dispersibility are excellent.
  • the content of the binder resin is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 14 parts by mass or less with respect to 100 parts by mass of the conductive powder.
  • Organic solvent is not particularly limited, and any known organic solvent capable of dissolving the binder resin can be used.
  • organic solvents include terpene-based solvents, glycol ether-based solvents, acetate-based solvents, acetic ester-based solvents, ketone-based solvents, and hydrocarbon solvents.
  • One type of organic solvent may be used, or two or more types may be used.
  • Terpene-based solvents include terpineol (TPO), dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), etc. Among them, dihydroterpineol (DHT) is preferred.
  • glycol ether solvents examples include (di)ethylene glycol ethers such as diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monohexyl ether, ethylene glycol monohexyl ether, and propylene glycol.
  • propylene glycol monoalkyl ethers such as monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether (PNB); Among them, propylene glycol monoalkyl ethers are preferred, and propylene glycol monobutyl ether (PNB) is more preferred.
  • the organic solvent contains a glycol ether-based solvent, it has excellent compatibility with the above-mentioned binder resin and excellent drying properties.
  • Acetate solvents include, for example, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate (butyl carbitol acetate: BCA), dipropylene glycol methyl ether acetate, 3-methoxy-3-methylbutyl acetate, 1-methoxypropyl-2- Glycol ether acetates such as acetate, and isobornyl acetate, isobornyl propinate, isobornyl butyrate, isobornyl isobutyrate and the like.
  • acetate solvent examples include ethyl acetate, propyl acetate, isobutyl acetate, and butyl acetate.
  • ketone-based solvents examples include methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone (DIBK), and the like.
  • hydrocarbon solvents examples include aliphatic hydrocarbon solvents such as tridecane, nonane, cyclohexane, naphthenic solvents and mineral spirits (MA), and aromatic hydrocarbon solvents such as toluene and xylene.
  • Group hydrocarbon solvents are preferred, and mineral spirits (MA) are more preferred.
  • the mineral spirit (MA) may contain a chain saturated hydrocarbon as a main component, and may contain 20% by mass or more of the saturated chain hydrocarbon with respect to the entire mineral spirit.
  • the organic solvent consists of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), terpineol (TPO), propylene glycol monobutyl ether (PNB), diethylene glycol monobutyl ether acetate (BCA), and diisobutyl ketone (DIBK). It is preferable to include one or more selected from the group. By using these solvents, it is possible to achieve both an appropriate viscosity and a drying speed.
  • DHT dihydroterpineol
  • DHTA dihydroterpinyl acetate
  • TPO terpineol
  • PPB propylene glycol monobutyl ether
  • BCA diethylene glycol monobutyl ether acetate
  • DIBK diisobutyl ketone
  • the organic solvent includes one or more terpene solvents (a) selected from the group consisting of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and terpineol (TPO), and propylene glycol monobutyl ether (PNB). , diethylene glycol monobutyl ether acetate (BCA), and a hydrocarbon solvent.
  • a terpene solvents
  • the organic solvent includes one or more terpene-based solvents (a) selected from the group consisting of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and terpineol (TPO), and propylene glycol monobutyl ether ( PNB), one or more solvents (b) selected from the group consisting of diethylene glycol monobutyl ether acetate (BCA), a hydrocarbon solvent, and diisobutyl ketone (DIBK).
  • DHT dihydroterpineol
  • DHTA dihydroterpinyl acetate
  • TPO terpineol
  • PNB propylene glycol monobutyl ether
  • solvents b
  • DIBK diisobutyl ketone
  • the content of the organic solvent is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 45% by mass or less, relative to the total amount of the conductive paste.
  • the content of the organic solvent is within the above range, the electroconductivity and dispersibility are excellent.
  • the content of the organic solvent is preferably 50 parts by mass or more and 130 parts by mass or less, more preferably 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the conductive powder.
  • the content of the organic solvent is within the above range, the electroconductivity and dispersibility are excellent.
  • the terpene-based solvent may be 5% by mass or more and 40% by mass or less, or 10% by mass or more and 30% by mass or less with respect to the total amount of the conductive paste. 12% by mass or more and 25% by mass or less.
  • the conductive paste contains a solvent (b) such as propylene glycol monobutyl ether (PNB), the content of the solvent (b) may be 3% by mass or 20% by mass or less with respect to the total amount of the conductive paste. , 5% by mass or more and 20% by mass or less.
  • a solvent (b) such as propylene glycol monobutyl ether (PNB)
  • the content of the solvent (b) may be 3% by mass or 20% by mass or less with respect to the total amount of the conductive paste. , 5% by mass or more and 20% by mass or less.
  • the hydrocarbon solvent may be 1% by mass or more and 20% by mass or less, or 3% by mass or more and 15% by mass or less with respect to the total amount of the conductive paste. It may be 5% by mass or more and 10% by mass or less.
  • the content of diisobutyl ketone (DIBK) is preferably 1% by mass or more and 20% by mass or less, and 3% by mass or more and 15% by mass. % by mass or less, or 3% by mass or more and 10% by mass or less.
  • the conductive paste according to this embodiment contains a carboxylic acid polymer dispersant having a molecular weight of 5000 or more.
  • the present inventor stably has a viscosity suitable for gravure printing by including a specific amount of a carboxylic acid polymer dispersant having a molecular weight of 5000 or more in a conductive paste for gravure printing, and It has been found that the separation between the conductive powder and the ceramic powder can be suppressed.
  • a carboxylic acid-based polymer dispersant is a polymer-based dispersant (surfactant) having a carboxylic acid group as an adsorption group.
  • the carboxylic acid-based polymeric dispersant may be, for example, a polymer (copolymer) produced by polymerizing two or more types of monomers including a carboxylic acid-containing monomer and a hydrophobic monomer. Moreover, this polymer may be synthesized by methods such as random polymerization, block polymerization, and graft polymerization.
  • carboxylic acid-based polymer dispersants include random polymers in which carboxylic acid-containing monomers and hydrophobic monomers are randomly arranged, and block polymers in which carboxylic acid group-containing monomers and hydrophobic monomers are arranged in blocks.
  • Examples include polymer-based dispersants having a structure, a comb-like structure, and the like.
  • a polymeric dispersant having a comb-shaped structure is obtained, for example, by polymerizing a carboxylic acid-containing monomer, a macromonomer, a hydrophobic monomer, or the like, and may have a graft chain.
  • the carboxylic acid polymer dispersant preferably contains a carboxylic acid polymer dispersant having a comb structure and/or a block polymer structure, and more preferably contains a carboxylic acid polymer dispersant having a comb structure.
  • the polymeric dispersant having a comb structure preferably has a graft chain, and the graft chain preferably contains an alkylene oxide polymer. Examples of the alkylene oxide polymer contained in the graft chain include ethylene oxide polymer, propylene oxide polymer, butylene oxide polymer, etc., and may include ethylene oxide polymer.
  • the average molecular weight of the carboxylic acid-based polymer dispersant is 5,000 or more, may be 10,000 or more, may be 20,000 or more, or may be 40,000 or more.
  • the average molecular weight of the carboxylic acid polymer dispersant affects the initial viscosity of the paste and the increase in viscosity over time. When the average molecular weight is 5000 or more, a stable dispersing effect can be exhibited, and thickening over time can be sufficiently suppressed.
  • the upper limit of the average molecular weight is not particularly limited from the viewpoint of suppressing thickening over time, if the average molecular weight is too large, the initial viscosity of the paste itself increases and may not be suitable for gravure printing. It may be 10,000 or less.
  • the average molecular weight is weight average molecular weight, and can be measured by GPC (gel permeation chromatography), for example.
  • the acid value of the carboxylic acid polymer dispersant is preferably 50 mgKOH/g or more and 250 mgKOH/g or less, and may be 50 mgKOH/g or more and 200 mgKOH/g or less. By setting the acid value within this range, a sufficient dispersing effect can be obtained.
  • the acid value (mgKOH/g) can be determined, for example, by potentiometric titration according to JIS K0070.
  • the carboxylic acid-based polymer dispersant is contained in an amount of 0.01% by mass or more and less than 2.0% by mass, preferably 0.01% by mass or more and 1.0% by mass or less, and more The content is preferably 0.03% by mass or more and 0.5% by mass or less.
  • a viscosity suitable for gravure printing can be stably maintained for a long period of time, and separation between the conductive powder and the ceramic powder can be suppressed.
  • the dispersant may consist only of a carboxylic acid-based polymer dispersant, but may also contain a dispersant other than a carboxylic acid-based polymer dispersant, as described later.
  • a dispersant other than a carboxylic acid-based polymer dispersant is included, the content of the carboxylic acid-based polymer dispersant may be, for example, 40% by mass or more, preferably 60% by mass, based on the total amount of the dispersant. or more, more preferably 80% by mass or more. As the content of the carboxylic acid-based polymer dispersant relative to the total amount of the dispersant increases, the effect of suppressing separation between the conductive powder and the ceramic powder is improved.
  • the conductive paste of the present embodiment may further contain an acid-based dispersant (a dispersant having an acidic adsorptive group) other than the carboxylic acid-based polymer dispersant.
  • an acid-based dispersant a dispersant having an acidic adsorptive group
  • the acid-based dispersant include carboxylic acid-based dispersants having an average molecular weight of less than 5,000, phosphoric acid-based dispersants, and other acidic polymer surfactants. mentioned. These acid dispersants may be used singly or in combination of two or more.
  • carboxylic acid-based dispersants having an average molecular weight of less than 5,000 include higher fatty acids, dicarboxylic acids, polycarboxylic acid-based dispersants, and alkylmonoamine salt-type carboxylic acid-based dispersants.
  • the conductive paste contains a carboxylic acid-based dispersant having an average molecular weight of less than 5000 together with the carboxylic acid-based polymer dispersant, the dispersibility of ceramic powder such as barium titanate may be further improved.
  • the average molecular weight of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 may be 2,000 or less, or may be 1,000 or less.
  • the higher fatty acid may be either an unsaturated carboxylic acid or a saturated carboxylic acid, and is not particularly limited, and includes stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, linolenic acid, etc., having 11 or more carbon atoms. are listed. Among them, oleic acid or stearic acid is preferable as the higher fatty acid.
  • alkyl monoamine salt types include oleoyl sarcosine, which is a compound of glycine and oleic acid, and stearic acid amide and lauryloyl, which are amide compounds using higher fatty acids such as stearic acid or lauric acid instead of oleic acid. Sarcosine is preferred.
  • the content of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 is too large, there is a concern that it may have an adverse effect such as inhibiting the adsorption of the carboxylic acid-based polymer dispersant to the metal powder material (filler). Therefore, when used in combination, it is preferable to appropriately adjust the content.
  • the content of the carboxylic dispersant having an average molecular weight of less than 5000 may be 60% by mass or less, preferably 40% by mass or less, more preferably 20% by mass, relative to the total amount of the dispersant. It is below.
  • the lower limit of the content of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 is 0% by mass.
  • the dispersant may or may not contain a dispersant other than an acid-based dispersant.
  • Dispersants other than acid dispersants include basic dispersants, nonionic dispersants, and amphoteric dispersants. These dispersants may be used singly or in combination of two or more.
  • Examples of basic dispersants include aliphatic amines such as laurylamine, rosinamine, cetylamine, myristylamine, stearylamine, and oleylamine.
  • the content of the basic dispersant may be, for example, 10% by mass or less or 5% by mass or less relative to the total amount of the dispersant.
  • the content of the dispersant (total) is preferably less than 3.0% by mass with respect to the entire conductive paste. Also, the content of the dispersant (total) may be 2% by mass or less, or may be 1.5% by mass or less with respect to the entire conductive paste. If the content of the carboxylic acid-based polymer dispersant or the total dispersant is too large, drying becomes insufficient in the printing and drying processes, and the internal electrode layers become soft. Misalignment may occur. In addition, the dispersing agent remaining during firing may be vaporized, and the vaporized gas component may generate internal stress or cause structural destruction of the laminate.
  • the conductive paste of the present embodiment may contain additives other than the above dispersant, if necessary.
  • additives conventionally known additives such as antifoaming agents, plasticizers and thickeners can be used.
  • Patent Document 3 describes a polycarboxylic acid polymer and a salt of a polycarboxylic acid as a separation suppressing agent for suppressing the separation of the conductive powder and the dielectric powder.
  • Separation inhibitors are also broadly included in acid-based dispersants as those that improve the dispersibility of inorganic powder.
  • the method for producing the conductive paste according to this embodiment is not particularly limited, and conventionally known methods can be used.
  • the conductive paste can be produced, for example, by stirring and kneading the above components with a three-roll mill, ball mill, mixer, or the like.
  • the dicarboxylic acid (separation inhibitor) is preferably added after being weighed when stirring and kneading with a mixer or the like, but after stirring and kneading (dispersion) A similar effect can be obtained even if it is added as a separation inhibitor to the material of (1).
  • the conductive paste preferably has a viscosity of 1.2 Pa ⁇ S or less at a shear rate of 100 sec ⁇ 1 .
  • the viscosity at a shear rate of 100 sec ⁇ 1 is within the above range, it can be suitably used as a conductive paste for gravure printing.
  • the viscosity is too high and may not be suitable for gravure printing.
  • the lower limit of the viscosity at a shear rate of 100 sec ⁇ 1 is not particularly limited, it is, for example, 0.2 Pa ⁇ S or more.
  • the thickness of the white layer observed one week after immediately after preparation is preferably less than 8%, and not more than 5%, of the entire thickness of the conductive paste. may be 2% or less.
  • the smaller the thickness of the white layer the more excellent the effect of suppressing separation between the conductive powder and the ceramic powder.
  • the thickness of the whitening layer can be measured by the method described in Examples described later.
  • the conductive paste of the present embodiment can be suitably used for electronic components such as multilayer ceramic capacitors.
  • a multilayer ceramic capacitor has dielectric layers and internal electrode layers formed using dielectric green sheets, and the conductive paste of the present embodiment can be suitably used for forming the internal electrode layers.
  • FIGS. 1A and 1B An example of an electronic component etc. according to the present embodiment will be described below with reference to the drawings. In the drawings, they may be represented schematically or may be represented by changing the scale as appropriate. Also, the positions and directions of the members will be described with reference to the XYZ orthogonal coordinate system shown in FIGS. 1A and 1B. In this XYZ orthogonal coordinate system, the X direction and the Y direction are horizontal directions, and the Z direction is the vertical direction (vertical direction).
  • FIGS. 1A and 1B are diagrams showing a laminated ceramic capacitor 1, which is an example of an electronic component.
  • a laminated ceramic capacitor 1 includes a laminate 10 in which dielectric layers 12 and internal electrode layers 11 are alternately laminated, and external electrodes 20 .
  • a conductive paste is gravure-printed on a ceramic green sheet (dielectric green sheet) and dried to form a dry film.
  • a plurality of ceramic green sheets having this dried film on the upper surface are laminated by pressure bonding to obtain a laminated body, and then the laminated body is fired and integrated, so that the internal electrode layers 11 and the dielectric layers 12 are alternately formed.
  • a ceramic laminate 10 is produced by laminating . After that, a pair of external electrodes 20 are formed on both ends of the ceramic laminate 10 to manufacture the laminated ceramic capacitor 1 .
  • a ceramic green sheet which is an unfired ceramic sheet.
  • a dielectric layer paste obtained by adding an organic binder such as polyvinyl butyral and a solvent such as terpineol to a predetermined ceramic raw material powder such as barium titanate is used as a PET film or the like.
  • examples include those obtained by coating a support film in the form of a sheet and drying to remove the solvent.
  • the thickness of the ceramic green sheet is not particularly limited, it is preferably 0.05 ⁇ m or more and 3 ⁇ m or less from the viewpoint of the demand for miniaturization of laminated ceramic capacitors.
  • the above-described conductive paste is applied by printing using a gravure printing method, and dried to form a dry film, and a plurality of sheets are prepared.
  • the thickness of the dried film is preferably 1 ⁇ m or less after drying.
  • the ceramic green sheets are peeled off from the support film, and after laminating so that the ceramic green sheets and the dry film formed on one side thereof are alternately arranged, a laminate is obtained by heat and pressure treatment. It should be noted that a configuration may be adopted in which protective ceramic green sheets to which the conductive paste is not applied are further arranged on both sides of the laminate.
  • the green chip is subjected to binder removal treatment and fired in a reducing atmosphere to obtain a laminated ceramic fired body (ceramic laminate 10).
  • the atmosphere in the binder removal treatment is preferably air or N2 gas atmosphere.
  • the temperature at which the binder removal treatment is performed is, for example, 200° C. or higher and 400° C. or lower. In addition, it is preferable that the temperature is maintained for 0.5 hours or more and 24 hours or less when the binder removal treatment is performed.
  • the firing is performed in a reducing atmosphere in order to suppress oxidation of the metal used for the internal electrode layers, and the temperature at which the laminate is fired is, for example, 1000° C. or higher and 1350° C. or lower.
  • the time for which the temperature is maintained is, for example, 0.5 hours or more and 8 hours or less.
  • the organic binder in the green sheet is completely removed, and the ceramic raw material powder is fired to form the ceramic dielectric layer 12 .
  • the organic vehicle in the dry film is removed, and the conductive powder is sintered or melted and integrated to form the internal electrode layer 11, and the dielectric layer 12 and the internal electrode layer 11 are formed into a plurality of sheets, A laminated ceramic sintered body that is alternately laminated is formed. From the viewpoint of taking oxygen into the dielectric layers to improve reliability and suppressing reoxidation of the internal electrodes, the laminated ceramic sintered body after sintering may be annealed.
  • the multilayer ceramic capacitor 1 is manufactured by providing a pair of external electrodes 20 to the manufactured multilayer ceramic sintered body.
  • the external electrode 20 comprises an external electrode layer 21 and a plated layer 22 .
  • the external electrode layers 21 are electrically connected to the internal electrode layers 11 .
  • the material of the external electrodes 20 for example, copper, nickel, or alloys thereof can be suitably used.
  • electronic components other than the laminated ceramic capacitor can be used as the electronic component.
  • the viscosity of the conductive paste is measured at 1 day and 1 week after production, the measured value at 1 day is defined as the initial viscosity, and the ratio of the measured value at 1 week to the initial viscosity (1 week at Measured value/measured value at 1 day) was evaluated as the thickening ratio over time.
  • An initial viscosity of 0.2 Pa ⁇ s or more and less than 1.2 Pa ⁇ s was evaluated as " ⁇ ", and a value of 1.2 Pa ⁇ s or more was evaluated as "x”.
  • a viscosity increase ratio over time of less than 1.3 was evaluated as "good” (sufficient viscosity stability), and a time-dependent thickening ratio of 1.3 or more was evaluated as “poor” (insufficient viscosity stability).
  • the ratio (%) of whitening is calculated by (thickness of layer of whitening/thickness of entire amount of paste)*100.
  • the whitening ratio (%) is less than 5% with " ⁇ " (separation suppression effect is good), 5% or more and less than 8% with " ⁇ " (separation suppression effect), 8% or more with "X" ( Insufficient separation suppression effect).
  • Ceramic powder Barium titanate (BaTiO 3 ; SEM average particle size 0.10 ⁇ m) was used as the ceramic powder.
  • binder resin Polyvinyl butyral and ethyl cellulose were used as the binder resin.
  • Carboxylic acid polymer dispersants 1 to 4 Carboxylic acid polymer dispersants 1 to 4, carboxylic acid low molecular dispersants 1 to 2, and amine polymer dispersant 1 having a molecular weight of 5000 or more were used. Details of each dispersant are summarized in Table 1.
  • the carboxylic acid polymer dispersant 4 has a linear block polymer structure (does not have a comb structure).
  • Organic solvents include propylene glycol monobutyl ether (PNB), butyl carbitol (BCA), mineral spirits (MA), terpineol (TPO), dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and diisobutyl ketone. (DIBK) was used.
  • PNB propylene glycol monobutyl ether
  • BCA butyl carbitol
  • MA mineral spirits
  • TPO terpineol
  • DHT dihydroterpineol
  • DHTA dihydroterpinyl acetate
  • DIBK diisobutyl ketone
  • Example 1 50% by mass of conductive powder, 12.5% by mass of ceramic powder, 0.05% by mass of dispersant (dispersant type: carboxylic acid polymer dispersant 1), 2.5% by mass of binder resin (polyvinyl butyral resin 1. 7% by mass, ethyl cellulose 0.8% by mass), and an organic solvent as the balance (solvent 1: balance, solvent 2: 9.5% by mass, solvent 3: 7% by mass) to give a total of 100% by mass.
  • a material blended so as to be was prepared.
  • a conductive paste was prepared by mixing and dispersing these materials.
  • solvent 1 is DHT
  • solvent 2 is PNB
  • solvent 3 is MA. Table 1 shows test conditions and evaluation results including details of additives.
  • Examples 2 to 10 Comparative Examples 1 to 3
  • a conductive paste was prepared and evaluated in the same manner as in Example 1, except that the type and amount of dispersant added and the solvents 1 to 3 were changed as shown in Tables 1 and 2.
  • the mixing ratio of the dispersant was adjusted by adjusting the amount of solvent 1 added so that the total amount of the conductive paste was 100% by mass. Details of the dispersant are shown in Table 1, and test conditions and evaluation results are shown in Table 2.
  • Example 11 The composition of the organic solvent was changed to contain four types, and the content of each was set to (solvent 1: balance, solvent 2: 5.3% by mass, solvent 3: 7% by mass, solvent 4: 4.2% by mass). .
  • a conductive paste was prepared and evaluated in the same manner as in Example 2 except that DHT was used as solvent 1, BCA was used as solvent 2, MSA was used as solvent 3, and DIBK was used as solvent 4. Details of the dispersant are shown in Table 1, and test conditions and evaluation results are shown in Table 2.
  • a carboxylic acid-based dispersant with a comb-shaped structure is used.
  • As a conductive paste an unacceptable increase in viscosity has occurred.
  • a low-molecular-weight carboxylic acid-based dispersant is used, and although the viscosity is sufficiently stable, the percentage of whitening exceeds the allowable amount.
  • the conductive paste of Comparative Example 3 uses a polymeric dispersant having a comb-shaped structure, but since the adsorption group is amine, the initial viscosity is high and it is not suitable for gravure printing.
  • Example 2 is a sample in which the content of the comb-shaped carboxylic acid-based polymer dispersant 1 used in Example 1 was increased, and better results were obtained in the initial viscosity, the ratio of thickening over time, and the amount of whitening. ing.
  • Examples 3 and 4 are samples using a comb-shaped carboxylic acid (Mw: 10,000 to 30,000) having a smaller average molecular weight than the comb-shaped carboxylic acid (Mw: 50,000) used in Example 2.
  • Mw 10,000 to 30,000
  • Mw comb-shaped carboxylic acid
  • the conductive pastes of Examples 3 and 4 have a slightly increased amount of whitening, and the conductive paste of Example 4 has a higher viscosity increase ratio over time.
  • the conductive paste of Example 5 uses a block polymerization type carboxylic acid-based polymer dispersant, and is added in a larger amount than other examples using a carboxylic acid-based polymer dispersant having a comb-shaped structure. By doing so, the same degree of effect as in other embodiments can be exhibited.
  • the conductive pastes of Examples 6 and 7 are a combination of a carboxylic acid-based comb-type polymer dispersant and a low-molecular-weight carboxylic acid-based dispersant.
  • the conductive pastes of Examples 6 and 7 have a similarly low thickening ratio over time as compared with the conductive paste of Example 2, which uses the same comb-shaped carboxylic acid-based polymer dispersant. The amount of whitening increases slightly.
  • the conductive pastes of Examples 6 and 7 are other examples using a dispersant having a smaller average molecular weight than the comb-shaped carboxylic acid polymer dispersant of Example 2 (Example: Example 4 , 5), the thickening ratio over time is low, but the amount of whitening tends to increase within the allowable range.
  • the conductive pastes of Examples 8, 9, 10 and 11 are samples obtained by changing the type of solvent in the conductive paste of Example 2. Even if the content of the solvent is the same, the viscosity, the time-dependent thickening ratio, and the amount of whitening change slightly by changing the combination of the types of solvents, but they do not change significantly. Therefore, it is possible to finely adjust the viscosity by selecting the type of solvent according to the usage conditions.
  • the conductive paste of the present invention stably has a viscosity suitable for gravure printing over a long period of time, and can sufficiently suppress separation between the conductive powder and the ceramic powder. Therefore, the conductive paste of the present invention can be suitably used as a raw material for internal electrodes of laminated ceramic capacitors, which are chip components of electronic devices such as mobile phones and digital devices, which are becoming increasingly compact. Moreover, the conductive paste of the present invention can be suitably used as a conductive paste for gravure printing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Physics & Mathematics (AREA)
  • Dispersion Chemistry (AREA)
  • Conductive Materials (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Ceramic Capacitors (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)

Abstract

The present invention provides a conductive paste for gravure printing, the conductive paste being able to be suppressed in separation between a conductive powder and a ceramic powder, thereby having good viscosity stability over time.　The present invention provides a conductive paste for gravure printing, the conductive paste containing a conductive powder, a ceramic powder, a dispersant, a binder resin and an organic solvent, wherein: the dispersant contains a carboxylic acid-based polymer dispersant that has a weight average molecular weight of 5,000 or more; and the carboxylic acid-based polymer dispersant is contained in an amount of not less than 0.01% by mass but less than 2.0% by mass relative to the total amount of the conductive paste.

Description

グラビア印刷用導電性ペースト、電子部品、及び積層セラミックコンデンサConductive paste for gravure printing, electronic components, and laminated ceramic capacitors
　本発明は、グラビア印刷用導電性ペースト、電子部品、及び積層セラミックコンデンサに関する。 The present invention relates to a conductive paste for gravure printing, electronic components, and laminated ceramic capacitors.
　携帯電話やデジタル機器などの電子機器の小型化および高性能化に伴い、積層セラミックコンデンサなどを含む電子部品についても小型化および高容量化が望まれている。積層セラミックコンデンサは、複数の誘電体層と複数の内部電極層とが交互に積層した構造を有し、これらの誘電体層及び内部電極層を薄膜化することにより、小型化及び高容量化を図ることができる。 With the miniaturization and high performance of electronic devices such as mobile phones and digital devices, there is a demand for miniaturization and high capacity electronic components, including multilayer ceramic capacitors. Multilayer ceramic capacitors have a structure in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated. By thinning these dielectric layers and internal electrode layers, miniaturization and high capacity can be achieved. can be planned.
　積層セラミックコンデンサは、例えば、次のように製造される。まず、チタン酸バリウム（ＢａＴｉＯ３）などの誘電体粉末及びバインダー樹脂を含有する誘電体グリーンシートの表面上に、導電性粉末、バインダー樹脂、及び、有機溶剤などを含む内部電極用ペースト（導電性ペースト）を、所定の電極パターンで印刷し、乾燥したものを、多層に積み重ねることにより、乾燥膜と誘電体グリーンシートとを多層に積み重ねた積層体を得る。次に、この積層体を加熱圧着して一体化し、圧着体を形成する。この圧着体を切断し、酸化性雰囲気または不活性雰囲気中にて脱有機バインダー処理を行った後、焼成を行い、内部電極層と誘電体層とが交互に積層した焼成チップを得る。次いで、焼成チップの両端部に外部電極用ペーストを塗布し、焼成後、外部電極表面にニッケルメッキなどを施して、積層セラミックコンデンサが得られる。 A laminated ceramic capacitor is manufactured, for example, as follows. First, on the surface of a dielectric green sheet containing dielectric powder such as barium titanate (BaTiO 3 ) and binder resin, an internal electrode paste (conductive paste) is printed in a predetermined electrode pattern, and the dried films are stacked in multiple layers to obtain a laminate in which the dried films and the dielectric green sheets are stacked in multiple layers. Next, this laminated body is thermocompression-bonded to be integrated to form a compression-bonded body. This compressed body is cut, subjected to organic binder removal treatment in an oxidizing atmosphere or inert atmosphere, and then fired to obtain fired chips in which internal electrode layers and dielectric layers are alternately laminated. Next, an external electrode paste is applied to both ends of the fired chip, and after firing, nickel plating or the like is applied to the surfaces of the external electrodes to obtain a multilayer ceramic capacitor.
　導電性ペーストを誘電体グリーンシートに印刷する際に用いられる印刷法としては、従来、スクリーン印刷法が一般的に用いられてきたが、電子デバイスの小型化、薄膜化や生産性向上の要求から、より微細な電極パターンを生産性高く印刷することが求められている。 Conventionally, screen printing has been commonly used as a printing method for printing conductive paste on dielectric green sheets. Therefore, it is required to print a finer electrode pattern with high productivity.
　導電性ペーストの印刷法の一つとして、製版に設けられた凹部に導電性ペーストを充填し、これを被印刷面に押し当てることでその製版から導電性ペーストを転写する連続印刷法であるグラビア印刷法が提案されている。グラビア印刷法は印刷速度が速く、生産性に優れる。グラビア印刷法を用いる場合、導電性ペースト中のバインダー樹脂、分散剤、溶剤等を適宜選択して、粘度等の特性をグラビア印刷に適した範囲に調整する必要がある。 As one of the printing methods of conductive paste, gravure is a continuous printing method in which the conductive paste is filled into the depressions provided in the plate making, and the conductive paste is transferred from the plate by pressing it against the surface to be printed. A printing method has been proposed. The gravure printing method has a high printing speed and excellent productivity. When the gravure printing method is used, it is necessary to appropriately select the binder resin, dispersant, solvent, etc. in the conductive paste to adjust the properties such as viscosity within the range suitable for gravure printing.
　例えば、特許文献１では、複数のセラミック層および前記セラミック層間の特定の界面に沿って延びる内部導体膜を備える積層セラミック電子部品における前記内部導体膜をグラビア印刷によって形成するために用いられる導電性ペーストであって、金属粉末を含む３０～７０重量％の固形成分と、１～１０重量％のエトキシ基含有率が４９．６％以上のエチルセルロース樹脂成分と、０．０５～５重量％の分散剤と、残部としての溶剤成分とを含み、ずり速度０．１（ｓ－１）での粘度η０．１が１Ｐａ・ｓ以上であり、かつずり速度０．０２（ｓ－１）での粘度η０．０２が特定の式で表わされる条件を満たす、チキソトロピー流体である、導電性ペーストが記載されている。 For example, in Patent Document 1, a conductive paste used for forming the internal conductor film in a laminated ceramic electronic component comprising a plurality of ceramic layers and an internal conductor film extending along a specific interface between the ceramic layers by gravure printing 30 to 70% by weight of a solid component containing metal powder, 1 to 10% by weight of an ethyl cellulose resin component having an ethoxy group content of 49.6% or more, and 0.05 to 5% by weight of a dispersant and a solvent component as the remainder, the viscosity η 0.1 at a shear rate of 0.1 (s -1 ) is 1 Pa s or more, and the viscosity at a shear rate of 0.02 (s -1 ) Conductive pastes are described which are thixotropic fluids with η 0.02 satisfying a specific formula.
　また、特許文献２では、上記特許文献１と同様にグラビア印刷によって形成するために用いられる導電性ペーストであって、金属粉末を含む３０～７０重量％の固形成分と、１～１０重量％の樹脂成分と、０．０５～５重量％の分散剤と、残部としての溶剤成分とを含み、ずり速度０．１（ｓ－１）での粘度が１Ｐａ・ｓ以上のチキソトロピー流体であって、ずり速度０．１（ｓ－１）での粘度を基準としたときに、ずり速度１０（ｓ－１）での粘度変化率が５０％以上である、導電性ペーストが記載されている。 Further, in Patent Document 2, a conductive paste used for forming by gravure printing in the same manner as in Patent Document 1, 30 to 70% by weight solid component containing metal powder, 1 to 10% by weight A thixotropic fluid containing a resin component, 0.05 to 5% by weight of a dispersant, and the balance of a solvent component, and having a viscosity of 1 Pa s or more at a shear rate of 0.1 (s -1 ), It describes a conductive paste having a viscosity change rate of 50% or more at a shear rate of 10 (s -1 ) based on the viscosity at a shear rate of 0.1 (s -1 ).
　上記特許文献１、２によれば、これらの導電性ペーストは、ずり速度０．１（ｓ－１）での粘度が１Ｐａ・ｓ以上であるチキソトロピー流体であり、グラビア印刷において高速での安定した連続印刷性が得られ、良好な生産効率で、積層セラミックコンデンサのような積層セラミック電子部品を製造することができるとされている。 According to the above Patent Documents 1 and 2, these conductive pastes are thixotropic fluids having a viscosity of 1 Pa s or more at a shear rate of 0.1 (s -1 ), and are stable at high speed in gravure printing. It is said that continuous printability can be obtained, and multilayer ceramic electronic components such as multilayer ceramic capacitors can be manufactured with good production efficiency.
　また、特許文献３には、導電性粉末（Ａ）、有機樹脂（Ｂ）、及び有機溶剤（Ｃ）、添加剤（Ｄ）、及び誘電体粉末（Ｅ）を含む積層セラミックコンデンサ内部電極用導電性ペーストであって、有機樹脂（Ｂ）は、重合度が１００００以上５００００以下のポリビニルブチラールと、重量平均分子量が１００００以上１０００００以下のエチルセルロースからなり、有機溶剤（Ｃ）は、プロピレングリコールモノブチルエーテル、もしくはプロピレングリコールモノブチルエーテルとプロピレングリコールメチルエーテルアセテートの混合溶剤、又はプロピレングリコールモノブチルエーテルとミネラルスピリットの混合溶剤のいずれかからなり、添加剤（Ｄ）は、分離抑制剤と分散剤からなるグラビア印刷用導電性ペーストが記載されている。特許文献３によれば、この導電性ペーストは、グラビア印刷に適した粘度を有し、かつ、乾燥性がよいとされている。 Further, Patent Document 3 discloses a conductive powder for internal electrodes of a multilayer ceramic capacitor containing conductive powder (A), organic resin (B), organic solvent (C), additive (D), and dielectric powder (E). organic resin (B) is polyvinyl butyral with a degree of polymerization of 10000 or more and 50000 or less, and ethyl cellulose with a weight average molecular weight of 10000 or more and 100000 or less, and the organic solvent (C) is propylene glycol monobutyl ether, Alternatively, it consists of either a mixed solvent of propylene glycol monobutyl ether and propylene glycol methyl ether acetate, or a mixed solvent of propylene glycol monobutyl ether and mineral spirits, and the additive (D) is a gravure printing agent consisting of a separation inhibitor and a dispersant. A conductive paste is described. According to Patent Document 3, this conductive paste has a viscosity suitable for gravure printing and is said to have good drying properties.
特開２００３－１８７６３８号公報Japanese Patent Application Laid-Open No. 2003-187638 特開２００３－２４２８３５号公報JP-A-2003-242835 特開２０１２－１７４７９７号公報JP 2012-174797 A
　グラビア印刷用の導電性ペーストでは、低粘度であることが要求される。しかしながら、低粘度の導電性ペーストでは、スクリーン印刷用などの高粘度の導電性ペーストと比較して、チタン酸バリウムなどのセラミック粉末とＮｉなどの導電性粉末とを添加した際に、これらの粉末の比重差による沈降速度差がより顕著に影響して、導電性粉末とセラミック粉末とが分離しやすい。 A conductive paste for gravure printing is required to have a low viscosity. However, in a low-viscosity conductive paste, compared with a high-viscosity conductive paste for screen printing, when a ceramic powder such as barium titanate and a conductive powder such as Ni are added, these powders The sedimentation velocity difference due to the difference in specific gravity has a more pronounced effect, and the conductive powder and the ceramic powder are easily separated.
　例えば、グラビア印刷用の導電性ペーストでは、導電性ペーストを作製した際にセラミック粉末を含む白い分離層が上部に発生する「白浮き」と称する現象（二層分離）が生じることがある。 For example, with conductive paste for gravure printing, a phenomenon called "whitening" (two-layer separation) may occur in which a white separation layer containing ceramic powder is generated at the top when the conductive paste is produced.
　また、本発明者らが検討した結果、スクリーン印刷用などの導電性ペーストと比較してグラビア印刷用の導電性ペーストは粘度が低いために、製造直後の粘度に対する長期保管後の粘度の比率として計算される経時増粘比が高くなりやすいことが分かった。スクリーン印刷と比較してグラビア印刷時の適切な粘度範囲は狭く、適用するペーストには粘度の精確な制御が求められるが、経時増粘比が高いペーストはグラビア印刷時に都度粘度調整が必要になるなど印刷工程が複雑化してしまうという問題があった。 In addition, as a result of examination by the present inventors, since the conductive paste for gravure printing has a lower viscosity than the conductive paste for screen printing, etc., the ratio of the viscosity after long-term storage to the viscosity immediately after production is It was found that the calculated thickening ratio over time tends to be high. Compared to screen printing, the appropriate viscosity range for gravure printing is narrower, and accurate viscosity control is required for the paste to be applied. There is a problem that the printing process is complicated.
　本発明は、このような状況に鑑み、グラビア印刷に適した低いペースト粘度を長期にわたり安定して有し、かつ、導電性粉末とセラミック粉末との分離を抑制することができる、導電性ペーストを提供することを目的とする。 In view of such circumstances, the present invention provides a conductive paste that has a low paste viscosity suitable for gravure printing stably over a long period of time and can suppress separation between the conductive powder and the ceramic powder. intended to provide
　本発明の第１の態様では、導電性粉末、セラミック粉末、分散剤、バインダー樹脂及び有機溶剤を含むグラビア印刷用導電性ペーストであって、分散剤は、重量平均分子量が５０００以上であるカルボン酸系高分子分散剤を含み、カルボン酸系高分子分散剤を、導電性ペースト全体に対して０．０１質量％以上２．０質量％未満含む、グラビア印刷用導電性ペーストが提供される。 In a first aspect of the present invention, a conductive paste for gravure printing containing a conductive powder, a ceramic powder, a dispersant, a binder resin and an organic solvent, wherein the dispersant is a carboxylic acid having a weight average molecular weight of 5000 or more Provided is a conductive paste for gravure printing containing a polymer dispersant and a carboxylic acid polymer dispersant in an amount of 0.01% by mass or more and less than 2.0% by mass with respect to the entire conductive paste.
　また、カルボン酸系高分子分散剤の酸価が５０ｍｇＫＯＨ／ｇ以上２５０ｍｇＫＯＨ／ｇ以下であることが好ましい。また、カルボン酸系高分子分散剤がくし型構造及び／又はブロックポリマー構造を有する高分子系分散剤を含むことが好ましい。また、くし型構造を有する高分子系分散剤がアルキレンオキシド重合体を含有する構成のグラフト鎖を有することが好ましい。 Also, the acid value of the carboxylic acid polymer dispersant is preferably 50 mgKOH/g or more and 250 mgKOH/g or less. Also, the carboxylic acid-based polymer dispersant preferably contains a polymer-based dispersant having a comb structure and/or a block polymer structure. Further, it is preferable that the polymeric dispersant having a comb structure has a graft chain containing an alkylene oxide polymer.
　また、有機溶剤がジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）、ターピネオール（ＴＰＯ）、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ジエチレングリコールモノブチルエーテルアセテート（ＢＣＡ）、およびジイソブチルケトン（ＤＩＢＫ）からなる群より選ばれる１種類以上を含むことが好ましい。 Also, the organic solvent is dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), terpineol (TPO), propylene glycol monobutyl ether (PNB), diethylene glycol monobutyl ether acetate (BCA), and the group consisting of diisobutyl ketone (DIBK) It is preferable to include one or more selected types.
　また、カルボン酸系高分子分散剤の含有量が、分散剤全量に対して６０質量％以上であってもよい。また、分散剤は、分子量が５０００未満であるカルボン酸系分散剤を、分散剤全量に対して、０質量％以上６０質量％以下含んでもよい。 Also, the content of the carboxylic acid polymer dispersant may be 60% by mass or more with respect to the total amount of the dispersant. Further, the dispersant may contain a carboxylic acid-based dispersant having a molecular weight of less than 5,000 in an amount of 0% by mass or more and 60% by mass or less based on the total amount of the dispersant.
　また、導電性粉末は、Ｎｉ、Ｐｄ、Ｐｔ、Ａｕ、Ａｇ、Ｃｕ及びこれらの合金から選ばれる１種以上の金属粉末を含むことが好ましい。また、導電性粉末は、平均粒径が０．０５μｍ以上１．０μｍ以下であることが好ましい。また、セラミック粉末は、チタン酸バリウムを含むことが好ましい。また、セラミック粉末は、平均粒径が０．０１μｍ以上０．５μｍ以下であることが好ましい。また、セラミック粉末は、導電性ペースト全体に対して１質量％以上２０質量％以下含まれることが好ましい。また、バインダー樹脂が、セルロース系樹脂を含むことが好ましい。 Also, the conductive powder preferably contains one or more metal powders selected from Ni, Pd, Pt, Au, Ag, Cu, and alloys thereof. Also, the conductive powder preferably has an average particle size of 0.05 μm or more and 1.0 μm or less. Also, the ceramic powder preferably contains barium titanate. Also, the ceramic powder preferably has an average particle size of 0.01 μm or more and 0.5 μm or less. Moreover, it is preferable that the ceramic powder is contained in an amount of 1% by mass or more and 20% by mass or less with respect to the entire conductive paste. Moreover, it is preferable that the binder resin contains a cellulose-based resin.
　また、グラビア印刷用導電性ペーストは、積層セラミック部品の内部電極用であることが好ましい。また、グラビア印刷用導電性ペーストは、ずり速度１００ｓｅｃ－１での粘度が１．２Ｐａ・Ｓ以下であることが好ましい。 Moreover, the conductive paste for gravure printing is preferably for internal electrodes of laminated ceramic parts. Further, the conductive paste for gravure printing preferably has a viscosity of 1.2 Pa·S or less at a shear rate of 100 sec −1 .
　本発明の第２の態様では、上記のグラビア印刷用導電性ペーストを用いて形成された電子部品が提供される。 A second aspect of the present invention provides an electronic component formed using the above conductive paste for gravure printing.
　本発明の第３の態様では、誘電体層と内部電極層とを積層した積層体を少なくとも有し、内部電極層は、上記のグラビア印刷用導電性ペーストを用いて形成された積層セラミックコンデンサが提供される。 In a third aspect of the present invention, a laminated ceramic capacitor having at least a laminated body in which a dielectric layer and an internal electrode layer are laminated, wherein the internal electrode layer is a laminated ceramic capacitor formed using the above conductive paste for gravure printing provided.
　本発明の導電性ペーストは、グラビア印刷に適した粘度特性を有し、低粘度のペースト中においても、導電性粉末とセラミック粉末との分離を抑制することができる。また、本発明の導電性ペーストは、長期にわたる粘度安定性が良好であるため印刷時の粘度調整が不要となり印刷工程の簡略化に寄与する。 The conductive paste of the present invention has viscosity characteristics suitable for gravure printing, and can suppress separation between the conductive powder and the ceramic powder even in a low-viscosity paste. In addition, the conductive paste of the present invention has good viscosity stability over a long period of time, so viscosity adjustment during printing becomes unnecessary, contributing to simplification of the printing process.
図１Ａ及び図１Ｂは、実施形態に係る積層セラミックコンデンサを示す斜視図（図１Ａ）及び断面図（図１Ｂ）である。1A and 1B are a perspective view (FIG. 1A) and a cross-sectional view (FIG. 1B) showing a laminated ceramic capacitor according to an embodiment.
［導電性ペースト］
　本実施形態の導電性ペーストは、導電性粉末、セラミック粉末、分散剤、バインダー樹脂及び有機溶剤を含む。以下、各成分について詳細に説明する。 [Conductive paste]
The conductive paste of this embodiment contains conductive powder, ceramic powder, dispersant, binder resin and organic solvent. Each component will be described in detail below.
（導電性粉末）
　導電性粉末としては、特に限定されず、金属粉末を用いることができ、例えば、Ｎｉ、Ｐｄ、Ｐｔ、Ａｕ、Ａｇ、Ｃｕ、およびこれらの合金から選ばれる１種以上の粉末を用いることができる。これらの中でも、導電性、耐食性及びコストの観点から、Ｎｉ、またはその合金（Ｎｉ合金）の粉末が好ましい。Ｎｉ合金としては、例えば、Ｍｎ、Ｃｒ、Ｃｏ、Ａｌ、Ｆｅ、Ｃｕ、Ｚｎ、Ａｇ、Ａｕ、ＰｔおよびＰｄからなる群より選択される少なくとも１種以上の元素とＮｉとの合金が用いることができる。Ｎｉ合金におけるＮｉの含有量は、例えば、５０質量％以上、好ましくは８０質量％以上である。また、Ｎｉ粉末は、脱バインダー処理の際、バインダー樹脂の部分的な熱分解による急激なガス発生を抑制するために、数百ｐｐｍ程度の元素Ｓを含んでもよい。 (Conductive powder)
The conductive powder is not particularly limited, and metal powder can be used. For example, one or more powders selected from Ni, Pd, Pt, Au, Ag, Cu, and alloys thereof can be used. . Among these, powder of Ni or its alloy (Ni alloy) is preferable from the viewpoint of conductivity, corrosion resistance and cost. As the Ni alloy, for example, an alloy of Ni and at least one element selected from the group consisting of Mn, Cr, Co, Al, Fe, Cu, Zn, Ag, Au, Pt and Pd can be used. can. The content of Ni in the Ni alloy is, for example, 50% by mass or more, preferably 80% by mass or more. In addition, the Ni powder may contain about several hundred ppm of the element S in order to suppress sudden gas generation due to partial thermal decomposition of the binder resin during the binder removal treatment.
　導電性粉末の平均粒径は、好ましくは０．０５μｍ以上１．０μｍ以下であり、より好ましくは０．１μｍ以上０．５μｍ以下である。導電性粉末の平均粒径が上記範囲である場合、薄膜化した積層セラミックコンデンサ（積層セラミック部品）の内部電極用ペーストとして好適に用いることができ、例えば、乾燥膜の平滑性及び乾燥膜密度が向上する。平均粒径は、走査型電子顕微鏡（ＳＥＭ）による観察から求められる値であり、ＳＥＭで倍率１０，０００倍にて観察した画像から、複数の粒子一つ一つの粒径を測定して、得られる平均値（ＳＥＭ平均粒径）である。 The average particle size of the conductive powder is preferably 0.05 µm or more and 1.0 µm or less, more preferably 0.1 µm or more and 0.5 µm or less. When the average particle diameter of the conductive powder is within the above range, it can be suitably used as a paste for internal electrodes of a thin laminated ceramic capacitor (laminated ceramic component). improves. The average particle size is a value obtained from observation with a scanning electron microscope (SEM), and is obtained by measuring the particle size of each of a plurality of particles from an image observed with a SEM at a magnification of 10,000. is the average value (SEM average particle size) obtained.
　導電性粉末の含有量は、導電性ペースト全体に対して、好ましくは３０質量％以上７０質量％未満であり、より好ましくは４０質量％以上６０質量％以下である。導電性粉末の含有量が上記範囲である場合、導電性及び分散性に優れる。 The content of the conductive powder is preferably 30% by mass or more and less than 70% by mass, more preferably 40% by mass or more and 60% by mass or less with respect to the entire conductive paste. When the content of the conductive powder is within the above range, the conductivity and dispersibility are excellent.
（セラミック粉末）
　セラミック粉末としては、特に限定されず、例えば、積層セラミックコンデンサの内部電極用ペーストである場合、適用する積層セラミックコンデンサの種類により適宜、公知のセラミック粉末が選択される。セラミック粉末としては、例えば、Ｂａ及びＴｉを含むペロブスカイト型酸化物を用いることができ、好ましくはチタン酸バリウム（ＢａＴｉＯ３）を含む。 (ceramic powder)
The ceramic powder is not particularly limited, and for example, in the case of a paste for internal electrodes of a laminated ceramic capacitor, a known ceramic powder is appropriately selected depending on the type of laminated ceramic capacitor to be applied. As the ceramic powder, for example, a perovskite-type oxide containing Ba and Ti can be used, preferably containing barium titanate (BaTiO 3 ).
　セラミック粉末としては、チタン酸バリウムを主成分とし、酸化物を副成分として含むセラミック粉末を用いてもよい。酸化物としては、Ｍｎ、Ｃｒ、Ｓｉ、Ｃａ、Ｂａ、Ｍｇ、Ｖ、Ｗ、Ｔａ、Ｎｂおよび希土類元素から選ばれる１種以上の酸化物が挙げられる。このようなセラミック粉末としては、例えば、チタン酸バリウム（ＢａＴｉＯ３）のＢａ原子やＴｉ原子を他の原子、例えば、Ｓｎ、Ｐｂ、Ｚｒなどで置換したペロブスカイト型酸化物強誘電体のセラミック粉末が挙げられる。 As the ceramic powder, a ceramic powder containing barium titanate as a main component and an oxide as an auxiliary component may be used. The oxides include one or more oxides selected from Mn, Cr, Si, Ca, Ba, Mg, V, W, Ta, Nb and rare earth elements. As such a ceramic powder, for example, there is a perovskite-type oxide ferroelectric ceramic powder in which Ba atoms or Ti atoms of barium titanate (BaTiO 3 ) are replaced with other atoms such as Sn, Pb, Zr, or the like. mentioned.
　内部電極用の導電性ペーストに用いるセラミック粉末は、積層セラミックコンデンサ（電子部品）のグリーンシートを構成する誘電体セラミック粉末と同一組成の粉末を用いてもよい。これにより、焼結工程における誘電体層と内部電極層との界面での収縮のミスマッチによるクラック発生が抑制される。このようなセラミック粉末としては、上記Ｂａ及びＴｉを含むペロブスカイト型酸化物以外に、例えば、ＺｎＯ、フェライト、ＰＺＴ、ＢａＯ、Ａｌ２Ｏ３、Ｂｉ２Ｏ３、Ｒ（希土類元素）２Ｏ３、ＴｉＯ２、Ｎｄ２Ｏ３などの酸化物が挙げられる。なお、セラミック粉末は、１種類を用いてもよく、２種類以上を用いてもよい。 The ceramic powder used in the conductive paste for the internal electrodes may have the same composition as the dielectric ceramic powder forming the green sheets of the multilayer ceramic capacitor (electronic component). As a result, the occurrence of cracks due to shrinkage mismatch at the interfaces between the dielectric layers and the internal electrode layers in the sintering process is suppressed. Examples of such ceramic powder include ZnO, ferrite, PZT, BaO, Al 2 O 3 , Bi 2 O 3 , R (rare earth element) 2 O 3 , in addition to the perovskite oxide containing Ba and Ti. Oxides such as TiO 2 and Nd 2 O 3 can be mentioned. One type of ceramic powder may be used, or two or more types may be used.
　セラミック粉末の平均粒径は、例えば、０．０１μｍ以上０．５μｍ以下であり、好ましくは０．０１μｍ以上０．３μｍ以下の範囲である。セラミック粉末の平均粒径が上記範囲であることにより、内部電極用ペーストとして用いた場合、十分に細く薄い均一な内部電極を形成することができる。平均粒径は、走査型電子顕微鏡（ＳＥＭ）による観察から求められる値であり、ＳＥＭで倍率５０，０００倍にて観察した映像から、複数の粒子一つ一つの粒径を測定して、得られる平均値（ＳＥＭ平均粒径）である。 The average particle size of the ceramic powder is, for example, 0.01 μm or more and 0.5 μm or less, preferably 0.01 μm or more and 0.3 μm or less. Since the average particle size of the ceramic powder is within the above range, when it is used as an internal electrode paste, sufficiently fine and thin uniform internal electrodes can be formed. The average particle size is a value obtained from observation with a scanning electron microscope (SEM), and is obtained by measuring the particle size of each of a plurality of particles from an image observed with a SEM at a magnification of 50,000. is the average value (SEM average particle size) obtained.
　セラミック粉末の含有量は、導電性ペースト全体に対して、好ましくは１質量％以上２０質量％以下であり、より好ましくは３質量％以上１５質量％以下である。セラミック粉末の含有量が上記範囲である場合、分散性および焼結性に優れる。 The content of the ceramic powder is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, relative to the entire conductive paste. When the content of the ceramic powder is within the above range, excellent dispersibility and sinterability are obtained.
　また、セラミック粉末の含有量は、導電性粉末１００質量部に対して、好ましくは１質量部以上３０質量部以下であり、より好ましくは３質量部以上３０質量部以下である。 In addition, the content of the ceramic powder is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 3 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the conductive powder.
（バインダー樹脂）
　バインダー樹脂としては、特に限定されず、公知の樹脂を用いることができる。バインダー樹脂としては、例えば、メチルセルロース、エチルセルロース、エチルヒドロキシエチルセルロース、ニトロセルロースなどのセルロース系樹脂、アクリル系樹脂、ポリビニルブチラールなどのブチラール系樹脂を含むアセタール系樹脂などが挙げられる。中でも、溶剤への溶解性、燃焼分解性の観点などから、セルロース系樹脂を含むことが好ましく、エチルセルロースを含むことがより好ましい。また、内部電極用ペーストとして用いる場合、グリーンシートとの接着強度を向上させる観点から、アセタール系樹脂を含む、又は、アセタール系樹脂単独で使用してもよい。また、バインダー樹脂は、例えば、セルロース系樹脂、及び、アセタール系樹脂の両方を含んでもよい。バインダー樹脂がアセタール系樹脂を含む場合、グラビア印刷に適した粘度に容易に調整することができ、かつ、グリーンシートとの接着強度をより向上させることができる。バインダー樹脂は、例えば、バインダー樹脂全体に対して、アセタール系樹脂を２０質量％以上含んでもよく、３０質量％以上含んでもよい。また、バインダー樹脂は、バインダー樹脂全体に対して、アセタール系樹脂を５０質量％以下含んでもよい。 (binder resin)
The binder resin is not particularly limited, and known resins can be used. Examples of binder resins include cellulose resins such as methyl cellulose, ethyl cellulose, ethylhydroxyethyl cellulose, and nitrocellulose, acrylic resins, and acetal resins including butyral resins such as polyvinyl butyral. Among them, from the viewpoint of solubility in a solvent, combustion decomposability, etc., it preferably contains a cellulose-based resin, and more preferably contains ethyl cellulose. When used as an internal electrode paste, it may contain an acetal resin or may be used alone from the viewpoint of improving the adhesive strength with the green sheet. Also, the binder resin may contain, for example, both a cellulose-based resin and an acetal-based resin. When the binder resin contains an acetal-based resin, the viscosity can be easily adjusted to suit gravure printing, and the adhesive strength with the green sheet can be further improved. The binder resin may contain, for example, 20% by mass or more, or 30% by mass or more of the acetal-based resin with respect to the entire binder resin. Moreover, the binder resin may contain 50% by mass or less of the acetal-based resin with respect to the entire binder resin.
　バインダー樹脂の重合度や重量平均分子量は、要求される導電性ペーストの粘度に応じて、上記範囲内で適宜調整することができる。 The degree of polymerization and weight average molecular weight of the binder resin can be appropriately adjusted within the above ranges according to the required viscosity of the conductive paste.
　バインダー樹脂の含有量は、導電性ペースト全体に対して、好ましくは０．５質量％以上１０質量％以下であり、より好ましくは１質量％以上７質量％以下である。バインダー樹脂の含有量が上記範囲である場合、導電性及び分散性に優れる。 The content of the binder resin is preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 7% by mass or less, relative to the entire conductive paste. When the content of the binder resin is within the above range, the conductivity and dispersibility are excellent.
　バインダー樹脂の含有量は、導電性粉末１００質量部に対して、好ましくは１質量部以上２０質量部以下であり、より好ましくは１質量部以上１４質量部以下である。 The content of the binder resin is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 14 parts by mass or less with respect to 100 parts by mass of the conductive powder.
（有機溶剤）
　有機溶剤としては、特に限定されず、上記バインダー樹脂を溶解することができる公知の有機溶剤を用いることができる。有機溶剤としては、例えば、テルペン系溶剤、グリコールエーテル系溶剤、アセテート系溶剤、酢酸エステル系溶剤、ケトン系溶剤、炭化水素溶剤などが挙げられる。なお、有機溶剤は、１種類を用いてもよく、２種類以上を用いてもよい。 (Organic solvent)
The organic solvent is not particularly limited, and any known organic solvent capable of dissolving the binder resin can be used. Examples of organic solvents include terpene-based solvents, glycol ether-based solvents, acetate-based solvents, acetic ester-based solvents, ketone-based solvents, and hydrocarbon solvents. One type of organic solvent may be used, or two or more types may be used.
　テルペン系溶剤としては、ターピネオール（ＴＰＯ）、ジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）などが挙げられ、中でも、ジヒドロターピネオール（ＤＨＴ）が好ましい。 Terpene-based solvents include terpineol (TPO), dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), etc. Among them, dihydroterpineol (DHT) is preferred.
　グリコールエーテル系溶剤としては、例えば、ジエチレングリコールモノ－２－エチルヘキシルエーテル、エチレングリコールモノ－２－エチルヘキシルエーテル、ジエチレングリコールモノヘキシルエーテル、エチレングリコールモノヘキシルエーテルなどの（ジ）エチレングリコールエーテル類、及び、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノプロピルエーテル、プロピレングリコールモノブチルエーテル（ＰＮＢ）などのプロピレングリコールモノアルキルエーテル類などが挙げられる。中でも、プロピレングリコールモノアルキルエーテル類が好ましく、プロピレングリコールモノブチルエーテル（ＰＮＢ）がより好ましい。有機溶剤がグリコールエーテル系溶剤を含む場合、上述したバインダー樹脂との相溶性に優れ、かつ、乾燥性に優れる。 Examples of glycol ether solvents include (di)ethylene glycol ethers such as diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monohexyl ether, ethylene glycol monohexyl ether, and propylene glycol. propylene glycol monoalkyl ethers such as monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether (PNB); Among them, propylene glycol monoalkyl ethers are preferred, and propylene glycol monobutyl ether (PNB) is more preferred. When the organic solvent contains a glycol ether-based solvent, it has excellent compatibility with the above-mentioned binder resin and excellent drying properties.
　アセテート系溶剤としては、例えば、エチレングリコールモノブチルエーテルアセテート、ジエチレングリコールモノブチルエーテルアセテート（ブチルカルビトールアセテート：ＢＣＡ）、ジプロピレングリコールメチルエーテルアセテート、３－メトキシー３－メチルブチルアセテート、１－メトキシプロピル－２－アセテートなどのグリコールエーテルアセテート類、及び、イソボルニルアセテート、イソボルニルプロピネート、イソボルニルブチレート、イソボルニルイソブチレートなどが挙げられる。 Acetate solvents include, for example, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate (butyl carbitol acetate: BCA), dipropylene glycol methyl ether acetate, 3-methoxy-3-methylbutyl acetate, 1-methoxypropyl-2- Glycol ether acetates such as acetate, and isobornyl acetate, isobornyl propinate, isobornyl butyrate, isobornyl isobutyrate and the like.
　酢酸エステル系溶剤としては、例えば、酢酸エチル、酢酸プロピル、酢酸イソブチル、酢酸ブチルなどが挙げられる。ケトン系溶剤としては、メチルエチルケトン、メチルイソブチルケトン、ジイソブチルケトン（ＤＩＢＫ）などが挙げられる。 Examples of the acetate solvent include ethyl acetate, propyl acetate, isobutyl acetate, and butyl acetate. Examples of ketone-based solvents include methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone (DIBK), and the like.
　炭化水素溶剤としては、トリデカン、ノナン、シクロヘキサン、ナフテン系溶剤、ミネラルスピリット（ＭＡ）などの脂肪族系炭化水素溶剤、及びトルエン、キシレンなどの芳香族系炭化水素溶剤などが挙げられ、中でも、脂肪族系炭化水素溶剤が好ましく、ミネラルスピリット（ＭＡ）がより好ましい。また、ミネラルスピリット（ＭＡ）は、鎖式飽和炭化水素を主成分として含んでもよく、鎖式飽和炭化水素をミネラルスピリット全体に対して、２０質量％以上含んでもよい。 Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as tridecane, nonane, cyclohexane, naphthenic solvents and mineral spirits (MA), and aromatic hydrocarbon solvents such as toluene and xylene. Group hydrocarbon solvents are preferred, and mineral spirits (MA) are more preferred. Moreover, the mineral spirit (MA) may contain a chain saturated hydrocarbon as a main component, and may contain 20% by mass or more of the saturated chain hydrocarbon with respect to the entire mineral spirit.
　また、有機溶剤は、ジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）、ターピネオール（ＴＰＯ）、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ジエチレングリコールモノブチルエーテルアセテート（ＢＣＡ）、およびジイソブチルケトン（ＤＩＢＫ）からなる群より選ばれる１種類以上を含むことが好ましい。これらの溶剤を用いることで、適切な粘度と乾燥速度を両立することができる。 Also, the organic solvent consists of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), terpineol (TPO), propylene glycol monobutyl ether (PNB), diethylene glycol monobutyl ether acetate (BCA), and diisobutyl ketone (DIBK). It is preferable to include one or more selected from the group. By using these solvents, it is possible to achieve both an appropriate viscosity and a drying speed.
　例えば、有機溶剤は、ジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）、ターピネオール（ＴＰＯ）からなる群より選ばれる１種類以上のテルペン系溶剤（ａ）と、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ジエチレングリコールモノブチルエーテルアセテート（ＢＣＡ）からなる群より選ばれる１種類以上の溶剤（ｂ）と、炭化水素溶剤とを含んでもよい。 For example, the organic solvent includes one or more terpene solvents (a) selected from the group consisting of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and terpineol (TPO), and propylene glycol monobutyl ether (PNB). , diethylene glycol monobutyl ether acetate (BCA), and a hydrocarbon solvent.
　また、例えば、有機溶剤は、ジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）、ターピネオール（ＴＰＯ）からなる群より選ばれる１種類以上のテルペン系溶剤（ａ）と、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ジエチレングリコールモノブチルエーテルアセテート（ＢＣＡ）からなる群より選ばれる１種類以上の溶剤（ｂ）と、炭化水素溶剤と、ジイソブチルケトン（ＤＩＢＫ）とを含んでもよい。 Further, for example, the organic solvent includes one or more terpene-based solvents (a) selected from the group consisting of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and terpineol (TPO), and propylene glycol monobutyl ether ( PNB), one or more solvents (b) selected from the group consisting of diethylene glycol monobutyl ether acetate (BCA), a hydrocarbon solvent, and diisobutyl ketone (DIBK).
　有機溶剤の含有量は、導電性ペースト全量に対して、２０質量％以上５０質量％以下が好ましく、２５質量％以上４５質量％以下がより好ましい。有機溶剤の含有量が上記範囲である場合、導電性及び分散性に優れる。 The content of the organic solvent is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 45% by mass or less, relative to the total amount of the conductive paste. When the content of the organic solvent is within the above range, the electroconductivity and dispersibility are excellent.
　有機溶剤の含有量は、導電性粉末１００質量部に対して、好ましくは５０質量部以上１３０質量部以下であり、より好ましくは６０質量部以上９０質量部以下である。有機溶剤の含有量が上記範囲である場合、導電性及び分散性に優れる。 The content of the organic solvent is preferably 50 parts by mass or more and 130 parts by mass or less, more preferably 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the conductive powder. When the content of the organic solvent is within the above range, the electroconductivity and dispersibility are excellent.
　導電性ペーストがテルペン系溶剤（ａ）を含む場合、テルペン系溶剤は、導電性ペースト全量に対して、５質量％以上４０質量％以下であってもよく、１０質量％以上３０質量％以下であってもよく、１２質量％以上２５質量％以下であってもよい。 When the conductive paste contains the terpene-based solvent (a), the terpene-based solvent may be 5% by mass or more and 40% by mass or less, or 10% by mass or more and 30% by mass or less with respect to the total amount of the conductive paste. 12% by mass or more and 25% by mass or less.
　導電性ペーストがプロピレングリコールモノブチルエーテル（ＰＮＢ）などの溶剤（ｂ）を含む場合、溶剤（ｂ）の含有量は、導電性ペースト全量に対して、３質量％２０質量％以下であってもよく、５質量％以上２０質量％以下であってもよい。 When the conductive paste contains a solvent (b) such as propylene glycol monobutyl ether (PNB), the content of the solvent (b) may be 3% by mass or 20% by mass or less with respect to the total amount of the conductive paste. , 5% by mass or more and 20% by mass or less.
　導電性ペーストが炭化水素溶剤を含む場合、炭化水素溶剤は、導電性ペースト全量に対して、１質量％以上２０質量％以下であってもよく、３質量％以上１５質量％以下であってもよく、５質量％以上１０質量％以下であってもよい。 When the conductive paste contains a hydrocarbon solvent, the hydrocarbon solvent may be 1% by mass or more and 20% by mass or less, or 3% by mass or more and 15% by mass or less with respect to the total amount of the conductive paste. It may be 5% by mass or more and 10% by mass or less.
　また、導電性ペーストが、ジイソブチルケトン（ＤＩＢＫ）を含む場合、ジイソブチルケトン（ＤＩＢＫ）の含有量は、導電性ペースト全量に対して、１質量％以上２０質量％以下が好ましく、３質量％以上１５質量％以下であってもよく、３質量％以上１０質量％以下であってもよい。 Further, when the conductive paste contains diisobutyl ketone (DIBK), the content of diisobutyl ketone (DIBK) is preferably 1% by mass or more and 20% by mass or less, and 3% by mass or more and 15% by mass. % by mass or less, or 3% by mass or more and 10% by mass or less.
（分散剤）
　本実施形態に係る導電性ペーストは、分子量が５０００以上であるカルボン酸系高分子分散剤を含む。本発明者は、グラビア印刷用の導電性ペーストにおいて、分子量が５０００以上であるカルボン酸系高分子分散剤を特定量で含むことにより、グラビア印刷に適した粘度を安定的に有し、かつ、導電性粉末とセラミック粉末との分離を抑制することができることを見出した。 (dispersant)
The conductive paste according to this embodiment contains a carboxylic acid polymer dispersant having a molecular weight of 5000 or more. The present inventor stably has a viscosity suitable for gravure printing by including a specific amount of a carboxylic acid polymer dispersant having a molecular weight of 5000 or more in a conductive paste for gravure printing, and It has been found that the separation between the conductive powder and the ceramic powder can be suppressed.
　カルボン酸系高分子分散剤は、吸着基としてカルボン酸基を有する高分子系の分散剤（界面活性剤）である。カルボン酸系高分子分散剤は、例えば、カルボン酸含有モノマーおよび疎水性モノマーを含む２種類以上のモノマーを重合して生成される重合体（コポリマー）であってもよい。また、この重合体は、ランダム重合、ブロック重合、グラフト重合などの方法で合成されてもよい。 A carboxylic acid-based polymer dispersant is a polymer-based dispersant (surfactant) having a carboxylic acid group as an adsorption group. The carboxylic acid-based polymeric dispersant may be, for example, a polymer (copolymer) produced by polymerizing two or more types of monomers including a carboxylic acid-containing monomer and a hydrophobic monomer. Moreover, this polymer may be synthesized by methods such as random polymerization, block polymerization, and graft polymerization.
　カルボン酸系高分子分散剤の例としては、カルボン酸含有モノマーと疎水性モノマー等がランダムに配列されたランダムポリマー、カルボン酸基含有モノマーと疎水性モノマー等がブロックに分かれて配列されたブロックポリマー構造、くし型構造などを有する高分子系分散剤が挙げられる。くし型構造を有する高分子系分散剤は、例えば、カルボン酸含有モノマー、マクロモノマー、疎水性モノマー等を重合して得られ、グラフト鎖を有してもよい。 Examples of carboxylic acid-based polymer dispersants include random polymers in which carboxylic acid-containing monomers and hydrophobic monomers are randomly arranged, and block polymers in which carboxylic acid group-containing monomers and hydrophobic monomers are arranged in blocks. Examples include polymer-based dispersants having a structure, a comb-like structure, and the like. A polymeric dispersant having a comb-shaped structure is obtained, for example, by polymerizing a carboxylic acid-containing monomer, a macromonomer, a hydrophobic monomer, or the like, and may have a graft chain.
　カルボン酸系高分子分散剤は、くし型構造及び／又はブロックポリマー構造を有するカルボン酸系高分子分散剤を含むことが好ましく、くし型構造を有するカルボン酸系高分子分散剤を含むことがより好ましい。また、くし型構造を有する高分子系分散剤は、グラフト鎖を有することが好ましく、グラフト鎖がアルキレンオキシド重合体を含有する構成であることが好ましい。グラフト鎖に含まれるアルキレンオキシド重合体としては、例えば、エチレンオキシド重合体、プロピレンオキシド重合体、ブチレンオキシド重合体などが挙げられ、エチレンオキシド重合体を含んでもよい。 The carboxylic acid polymer dispersant preferably contains a carboxylic acid polymer dispersant having a comb structure and/or a block polymer structure, and more preferably contains a carboxylic acid polymer dispersant having a comb structure. preferable. Further, the polymeric dispersant having a comb structure preferably has a graft chain, and the graft chain preferably contains an alkylene oxide polymer. Examples of the alkylene oxide polymer contained in the graft chain include ethylene oxide polymer, propylene oxide polymer, butylene oxide polymer, etc., and may include ethylene oxide polymer.
　また、カルボン酸系高分子分散剤の平均分子量は５０００以上であり、１００００以上であってもよく、２００００以上であってもよく、４００００以上であってもよい。カルボン酸系高分子分散剤の平均分子量は、ペーストの初期粘度及び経時増粘などに影響を及ぼす。平均分子量が５０００以上である場合、安定した分散効果を発揮することができ、経時増粘を十分に抑制することができる。なお、経時増粘を抑制する観点では平均分子量の上限は特に限定されないが、平均分子量が大きすぎる場合にはペーストの初期粘度自体が高くなりグラビア印刷に適さなくなることがあるため、平均分子量は１０万以下であってもよい。なお、平均分子量は、重量平均分子量であり、例えば、ＧＰＣ（ゲルパーミエーションクロマトグラフィー）により測定することができる。 In addition, the average molecular weight of the carboxylic acid-based polymer dispersant is 5,000 or more, may be 10,000 or more, may be 20,000 or more, or may be 40,000 or more. The average molecular weight of the carboxylic acid polymer dispersant affects the initial viscosity of the paste and the increase in viscosity over time. When the average molecular weight is 5000 or more, a stable dispersing effect can be exhibited, and thickening over time can be sufficiently suppressed. Although the upper limit of the average molecular weight is not particularly limited from the viewpoint of suppressing thickening over time, if the average molecular weight is too large, the initial viscosity of the paste itself increases and may not be suitable for gravure printing. It may be 10,000 or less. The average molecular weight is weight average molecular weight, and can be measured by GPC (gel permeation chromatography), for example.
　また、カルボン酸系高分子分散剤の酸価は、５０ｍｇＫＯＨ／ｇ以上２５０ｍｇＫＯＨ／ｇ以下であることが好ましく、５０ｍｇＫＯＨ／ｇ以上２００ｍｇＫＯＨ／ｇ以下であってもよい。酸価がこの範囲であることにより、十分な分散効果が得られる。なお、酸価（ｍｇＫＯＨ／ｇ）は、例えば、ＪＩＳ　Ｋ００７０に準拠して電位差滴定法により求めることができる。 Also, the acid value of the carboxylic acid polymer dispersant is preferably 50 mgKOH/g or more and 250 mgKOH/g or less, and may be 50 mgKOH/g or more and 200 mgKOH/g or less. By setting the acid value within this range, a sufficient dispersing effect can be obtained. The acid value (mgKOH/g) can be determined, for example, by potentiometric titration according to JIS K0070.
　また、上記カルボン酸系高分子分散剤は、導電性ペースト全体に対して０．０１質量％以上２．０質量％未満含まれ、好ましくは０．０１質量％以上１．０質量％以下、より好ましくは０．０３質量％以上０．５質量％以下含まれる。カルボン酸系高分子分散剤を上記範囲で含む場合、グラビア印刷に適した粘度を長期間安定的に有することができ、かつ、導電性粉末とセラミック粉末との分離を抑制することができる。 In addition, the carboxylic acid-based polymer dispersant is contained in an amount of 0.01% by mass or more and less than 2.0% by mass, preferably 0.01% by mass or more and 1.0% by mass or less, and more The content is preferably 0.03% by mass or more and 0.5% by mass or less. When the carboxylic acid-based polymer dispersant is contained within the above range, a viscosity suitable for gravure printing can be stably maintained for a long period of time, and separation between the conductive powder and the ceramic powder can be suppressed.
　また、分散剤は、カルボン酸系高分子分散剤のみから構成されてもよいが、後述するようにカルボン酸系高分子分散剤以外の分散剤を含んでもよい。カルボン酸系高分子分散剤以外の分散剤を含む場合、カルボン酸系高分子分散剤の含有量は、例えば、分散剤全量に対して４０質量％以上であってもよく、好ましくは６０質量％以上であり、より好ましくは８０質量％以上である。カルボン酸系高分子分散剤の分散剤全量に対する含有量が多いほど、導電性粉末とセラミック粉末との分離抑制の効果が向上する。 In addition, the dispersant may consist only of a carboxylic acid-based polymer dispersant, but may also contain a dispersant other than a carboxylic acid-based polymer dispersant, as described later. When a dispersant other than a carboxylic acid-based polymer dispersant is included, the content of the carboxylic acid-based polymer dispersant may be, for example, 40% by mass or more, preferably 60% by mass, based on the total amount of the dispersant. or more, more preferably 80% by mass or more. As the content of the carboxylic acid-based polymer dispersant relative to the total amount of the dispersant increases, the effect of suppressing separation between the conductive powder and the ceramic powder is improved.
　また、本実施形態の導電性ペーストは、上記カルボン酸系高分子分散剤以外の酸系分散剤（酸性の吸着基を有する分散剤）をさらに含んでもよい。酸系分散剤（上記カルボン酸系高分子分散剤を除く）としては、例えば、平均分子量が５０００未満のカルボン酸系分散剤、リン酸系分散剤、その他の酸系高分子界面活性剤などが挙げられる。なお、これらの酸系分散剤は、１種または２種以上組み合わせて用いてもよい。 In addition, the conductive paste of the present embodiment may further contain an acid-based dispersant (a dispersant having an acidic adsorptive group) other than the carboxylic acid-based polymer dispersant. Examples of the acid-based dispersant (excluding the carboxylic acid-based polymer dispersant) include carboxylic acid-based dispersants having an average molecular weight of less than 5,000, phosphoric acid-based dispersants, and other acidic polymer surfactants. mentioned. These acid dispersants may be used singly or in combination of two or more.
　平均分子量が５０００未満のカルボン酸系分散剤としては、例えば、高級脂肪酸、ジカルボン酸、ポリカルボン酸系分散剤、アルキルモノアミン塩型などのカルボン酸系分散剤が挙げられる。導電性ペーストは、上記カルボン酸系高分子分散剤とともに平均分子量が５０００未満のカルボン酸系分散剤を含む場合、チタン酸バリウムなどのセラミック粉末の分散性がより向上することがある。なお、平均分子量が５０００未満のカルボン酸系分散剤の平均分子量は、２０００以下であってもよく、１０００以下であってもよい。 Examples of carboxylic acid-based dispersants having an average molecular weight of less than 5,000 include higher fatty acids, dicarboxylic acids, polycarboxylic acid-based dispersants, and alkylmonoamine salt-type carboxylic acid-based dispersants. When the conductive paste contains a carboxylic acid-based dispersant having an average molecular weight of less than 5000 together with the carboxylic acid-based polymer dispersant, the dispersibility of ceramic powder such as barium titanate may be further improved. The average molecular weight of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 may be 2,000 or less, or may be 1,000 or less.
　高級脂肪酸としては、不飽和カルボン酸でも飽和カルボン酸でもよく、特に限定されるものではないが、ステアリン酸、オレイン酸、ミリスチン酸、パルミチン酸、リノール酸、ラウリン酸、リノレン酸など炭素数１１以上のものが挙げられる。中でも、高級脂肪酸としては、オレイン酸、またはステアリン酸が好ましい。 The higher fatty acid may be either an unsaturated carboxylic acid or a saturated carboxylic acid, and is not particularly limited, and includes stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, linolenic acid, etc., having 11 or more carbon atoms. are listed. Among them, oleic acid or stearic acid is preferable as the higher fatty acid.
　アルキルモノアミン塩型としては、例えば、グリシンとオレイン酸の化合物であるオレオイルザルコシンや、オレイン酸の代わりにステアリン酸あるいはラウリン酸などの高級脂肪酸を用いたアミド化合物であるステアリン酸アミド、ラウリロイルザルコシンが好ましい。 Examples of alkyl monoamine salt types include oleoyl sarcosine, which is a compound of glycine and oleic acid, and stearic acid amide and lauryloyl, which are amide compounds using higher fatty acids such as stearic acid or lauric acid instead of oleic acid. Sarcosine is preferred.
　なお、平均分子量が５０００未満のカルボン酸系分散剤の含有量が多すぎる場合、上記カルボン酸系高分子分散剤の金属粉末材料（フィラー）への吸着を阻害するなどの悪影響を及ぼす懸念があるため、併用する際はその含有量を適宜調整することが好ましい。 If the content of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 is too large, there is a concern that it may have an adverse effect such as inhibiting the adsorption of the carboxylic acid-based polymer dispersant to the metal powder material (filler). Therefore, when used in combination, it is preferable to appropriately adjust the content.
　例えば、平均分子量が５０００未満であるカルボン酸系分散剤の含有量は、分散剤全量に対して６０質量％以下であってもよく、好ましくは４０質量％以下であり、より好ましくは２０質量％以下である。また、平均分子量が５０００未満であるカルボン酸系分散剤の含有量の下限は０質量％である。 For example, the content of the carboxylic dispersant having an average molecular weight of less than 5000 may be 60% by mass or less, preferably 40% by mass or less, more preferably 20% by mass, relative to the total amount of the dispersant. It is below. Moreover, the lower limit of the content of the carboxylic acid-based dispersant having an average molecular weight of less than 5,000 is 0% by mass.
　また、分散剤は、酸系分散剤以外の分散剤を含んでもよいし、含まなくてもよい。酸系分散剤以外の分散剤としては、塩基系分散剤、非イオン系分散剤、両性分散剤などが挙げられる。これらの分散剤は、１種または２種以上組み合わせて用いてもよい。 In addition, the dispersant may or may not contain a dispersant other than an acid-based dispersant. Dispersants other than acid dispersants include basic dispersants, nonionic dispersants, and amphoteric dispersants. These dispersants may be used singly or in combination of two or more.
　塩基系分散剤としては、例えば、ラウリルアミン、ロジンアミン、セチルアミン、ミリスチルアミン、ステアリルアミン、オレイルアミンなどの脂肪族アミンなどが挙げられる。塩基系分散剤の含有量は、例えば、分散剤全量に対して１０質量％以下であってもよく、５質量％以下であってもよい。 Examples of basic dispersants include aliphatic amines such as laurylamine, rosinamine, cetylamine, myristylamine, stearylamine, and oleylamine. The content of the basic dispersant may be, for example, 10% by mass or less or 5% by mass or less relative to the total amount of the dispersant.
　また、分散剤（全体）の含有量としては、導電性ペースト全体に対して３．０質量％未満であることが好ましい。また、分散剤（全体）の含有量は、導電性ペースト全体に対して２％質量以下であってもよく、１．５質量％以下であってもよい。上記カルボン酸系高分子分散剤、又は、分散剤全体の含有量が多すぎる場合、印刷、乾燥工程で、乾燥が不十分となり、内部電極層が柔らかい状態となるため、その後の積層工程で積層ズレを生じることがある。また、焼成時に残留した分散剤が気化し、気化したガス成分によって内部応力が発生したり、積層体の構造破壊が生じたりすることがある。 Also, the content of the dispersant (total) is preferably less than 3.0% by mass with respect to the entire conductive paste. Also, the content of the dispersant (total) may be 2% by mass or less, or may be 1.5% by mass or less with respect to the entire conductive paste. If the content of the carboxylic acid-based polymer dispersant or the total dispersant is too large, drying becomes insufficient in the printing and drying processes, and the internal electrode layers become soft. Misalignment may occur. In addition, the dispersing agent remaining during firing may be vaporized, and the vaporized gas component may generate internal stress or cause structural destruction of the laminate.
（添加剤）
　本実施形態の導電性ペーストは、必要に応じて、上記の分散剤以外のその他の添加剤を含んでもよい。その他の添加剤としては、例えば、消泡剤、可塑剤、増粘剤などの従来公知の添加物を用いることができる。 (Additive)
The conductive paste of the present embodiment may contain additives other than the above dispersant, if necessary. As other additives, conventionally known additives such as antifoaming agents, plasticizers and thickeners can be used.
　なお、例えば、特許文献３では、導電性粉末と誘電体粉末の分離を抑制する分離抑制剤として、ポリカルボン酸ポリマーおよびポリカルボン酸の塩が記載されているが、本明細書では、このような分離抑制剤も広義には無機粉末の分散性を向上させるものとして酸系分散剤に含める。 For example, Patent Document 3 describes a polycarboxylic acid polymer and a salt of a polycarboxylic acid as a separation suppressing agent for suppressing the separation of the conductive powder and the dielectric powder. Separation inhibitors are also broadly included in acid-based dispersants as those that improve the dispersibility of inorganic powder.
（導電性ペースト）
　本実施形態に係る導電性ペーストの製造方法は、特に限定されず、従来公知の方法を用いることができる。導電性ペーストは、例えば、上記の各成分を、３本ロールミル、ボールミル、ミキサーなどで攪拌・混練することにより製造することができる。なお、ジカルボン酸（分離抑制剤）については、他の材料と同様に、ミキサーなどで撹拌・混錬装置する際に秤量して、添加することが好ましいが、撹拌・混錬（分散）終了後の材料に、分離抑制剤として添加しても同様の効果を得ることができる。 (Conductive paste)
The method for producing the conductive paste according to this embodiment is not particularly limited, and conventionally known methods can be used. The conductive paste can be produced, for example, by stirring and kneading the above components with a three-roll mill, ball mill, mixer, or the like. As with the other materials, the dicarboxylic acid (separation inhibitor) is preferably added after being weighed when stirring and kneading with a mixer or the like, but after stirring and kneading (dispersion) A similar effect can be obtained even if it is added as a separation inhibitor to the material of (1).
　導電性ペーストは、ずり速度１００ｓｅｃ－１の粘度が、好ましくは１．２Ｐａ・Ｓ以下である。ずり速度１００ｓｅｃ－１の粘度が上記範囲である場合、グラビア印刷用の導電性ペーストとして好適に用いることができる。上記範囲を超えると粘度が高すぎてグラビア印刷用として適さない場合がある。ずり速度１００ｓｅｃ－１の粘度の下限は、特に限定されないが、例えば、０．２Ｐａ・Ｓ以上である。 The conductive paste preferably has a viscosity of 1.2 Pa·S or less at a shear rate of 100 sec −1 . When the viscosity at a shear rate of 100 sec −1 is within the above range, it can be suitably used as a conductive paste for gravure printing. When the above range is exceeded, the viscosity is too high and may not be suitable for gravure printing. Although the lower limit of the viscosity at a shear rate of 100 sec −1 is not particularly limited, it is, for example, 0.2 Pa·S or more.
　また、導電性ペーストは、作製直後から１週間経過後に観察される白浮きの層の厚みが、導電性ペースト全体の厚みに対して、８％未満であることが好ましく、５％以下であってもよく、２％以下であってもよい。白浮きの層の厚みが少ないほど、導電性粉末とセラミック粉末の分離抑制効果に優れる。なお、白浮きの層の厚みは、後述する実施例に記載の方法で測定することができる。 In addition, in the conductive paste, the thickness of the white layer observed one week after immediately after preparation is preferably less than 8%, and not more than 5%, of the entire thickness of the conductive paste. may be 2% or less. The smaller the thickness of the white layer, the more excellent the effect of suppressing separation between the conductive powder and the ceramic powder. In addition, the thickness of the whitening layer can be measured by the method described in Examples described later.
　また、本実施形態の導電性ペーストは、積層セラミックコンデンサなどの電子部品に好適に用いることができる。積層セラミックコンデンサは、誘電体グリーンシートを用いて形成される誘電体層及び内部電極層を有し、本実施形態の導電性ペーストは、内部電極層の形成に好適用いることができる。 Also, the conductive paste of the present embodiment can be suitably used for electronic components such as multilayer ceramic capacitors. A multilayer ceramic capacitor has dielectric layers and internal electrode layers formed using dielectric green sheets, and the conductive paste of the present embodiment can be suitably used for forming the internal electrode layers.
［電子部品］
　以下、本実施形態に係る電子部品等の一例について、図面を参照しながら説明する。図面においては、適宜、模式的に表現することや、縮尺を変更して表現することがある。また、部材の位置や方向などを、適宜、図１Ａ及び図１Ｂに示すＸＹＺ直交座標系を参照して説明する。このＸＹＺ直交座標系において、Ｘ方向およびＹ方向は水平方向であり、Ｚ方向は鉛直方向（上下方向）である。 [Electronic parts]
An example of an electronic component etc. according to the present embodiment will be described below with reference to the drawings. In the drawings, they may be represented schematically or may be represented by changing the scale as appropriate. Also, the positions and directions of the members will be described with reference to the XYZ orthogonal coordinate system shown in FIGS. 1A and 1B. In this XYZ orthogonal coordinate system, the X direction and the Y direction are horizontal directions, and the Z direction is the vertical direction (vertical direction).
　図１Ａ及びＢは、電子部品の一例である、積層セラミックコンデンサ１を示す図である。積層セラミックコンデンサ１は、誘電体層１２及び内部電極層１１を交互に積層した積層体１０と外部電極２０とを備える。 FIGS. 1A and 1B are diagrams showing a laminated ceramic capacitor 1, which is an example of an electronic component. A laminated ceramic capacitor 1 includes a laminate 10 in which dielectric layers 12 and internal electrode layers 11 are alternately laminated, and external electrodes 20 .
　以下、上記導電性ペーストを使用した積層セラミックコンデンサの製造方法の一例について説明する。まず、セラミックグリーンシート（誘電体グリーンシート）上に、導電性ペーストをグラビア印刷し、乾燥して、乾燥膜を形成する。この乾燥膜を上面に有する複数のセラミックグリーンシートを、圧着により積層させて積層体を得た後、積層体を焼成して一体化することにより、内部電極層１１と誘電体層１２とが交互に積層したセラミック積層体１０を作製する。その後、セラミック積層体１０の両端部に一対の外部電極２０を形成することにより積層セラミックコンデンサ１が製造される。以下に、より詳細に説明する。 An example of a method for manufacturing a multilayer ceramic capacitor using the conductive paste will be described below. First, a conductive paste is gravure-printed on a ceramic green sheet (dielectric green sheet) and dried to form a dry film. A plurality of ceramic green sheets having this dried film on the upper surface are laminated by pressure bonding to obtain a laminated body, and then the laminated body is fired and integrated, so that the internal electrode layers 11 and the dielectric layers 12 are alternately formed. A ceramic laminate 10 is produced by laminating . After that, a pair of external electrodes 20 are formed on both ends of the ceramic laminate 10 to manufacture the laminated ceramic capacitor 1 . A more detailed description follows.
　まず、未焼成のセラミックシートであるセラミックグリーンシートを用意する。このセラミックグリーンシートとしては、例えば、チタン酸バリウム等の所定のセラミックの原料粉末に、ポリビニルブチラール等の有機バインダーとターピネオール等の溶剤とを加えて得た誘電体層用ペーストを、ＰＥＴフィルム等の支持フィルム上にシート状に塗布し、乾燥させて溶剤を除去したもの等が挙げられる。なお、セラミックグリーンシートの厚みは、特に限定されないが、積層セラミックコンデンサの小型化の要請の観点から、０．０５μｍ以上３μｍ以下が好ましい。 First, prepare a ceramic green sheet, which is an unfired ceramic sheet. As the ceramic green sheet, for example, a dielectric layer paste obtained by adding an organic binder such as polyvinyl butyral and a solvent such as terpineol to a predetermined ceramic raw material powder such as barium titanate is used as a PET film or the like. Examples include those obtained by coating a support film in the form of a sheet and drying to remove the solvent. Although the thickness of the ceramic green sheet is not particularly limited, it is preferably 0.05 μm or more and 3 μm or less from the viewpoint of the demand for miniaturization of laminated ceramic capacitors.
　次いで、このセラミックグリーンシートの片面に、グラビア印刷法を用いて、上述の導電性ペーストを印刷により塗布し、乾燥して、乾燥膜を形成したものを複数枚、用意する。なお、乾燥膜の厚みは、内部電極層１１の薄層化の要請の観点から、乾燥後１μｍ以下とすることが好ましい。 Next, on one side of this ceramic green sheet, the above-described conductive paste is applied by printing using a gravure printing method, and dried to form a dry film, and a plurality of sheets are prepared. From the viewpoint of the demand for thinning of the internal electrode layers 11, the thickness of the dried film is preferably 1 μm or less after drying.
　次いで、支持フィルムから、セラミックグリーンシートを剥離するとともに、セラミックグリーンシートとその片面に形成された乾燥膜とが交互に配置されるように積層した後、加熱・加圧処理により積層体を得る。なお、積層体の両面に、導電性ペーストを塗布していない保護用のセラミックグリーンシートを更に配置する構成としても良い。 Next, the ceramic green sheets are peeled off from the support film, and after laminating so that the ceramic green sheets and the dry film formed on one side thereof are alternately arranged, a laminate is obtained by heat and pressure treatment. It should be noted that a configuration may be adopted in which protective ceramic green sheets to which the conductive paste is not applied are further arranged on both sides of the laminate.
　次いで、積層体を所定サイズに切断してグリーンチップを形成した後、当該グリーンチップに対して脱バインダー処理を施し、還元雰囲気下において焼成することにより、積層セラミック焼成体（セラミック積層体１０）を製造する。なお、脱バインダー処理における雰囲気は、大気またはＮ２ガス雰囲気にすることが好ましい。脱バインダー処理を行う際の温度は、例えば２００℃以上４００℃以下である。また、脱バインダー処理を行う際の、上記温度の保持時間を０．５時間以上２４時間以下とすることが好ましい。また、焼成は、内部電極層に用いる金属の酸化を抑制するために還元雰囲気で行われ、また、積層体の焼成を行う際の温度は、例えば、１０００℃以上１３５０℃以下であり、焼成を行う際の、温度の保持時間は、例えば、０．５時間以上８時間以下である。 Next, after cutting the laminate into a predetermined size to form a green chip, the green chip is subjected to binder removal treatment and fired in a reducing atmosphere to obtain a laminated ceramic fired body (ceramic laminate 10). manufacture. The atmosphere in the binder removal treatment is preferably air or N2 gas atmosphere. The temperature at which the binder removal treatment is performed is, for example, 200° C. or higher and 400° C. or lower. In addition, it is preferable that the temperature is maintained for 0.5 hours or more and 24 hours or less when the binder removal treatment is performed. Further, the firing is performed in a reducing atmosphere in order to suppress oxidation of the metal used for the internal electrode layers, and the temperature at which the laminate is fired is, for example, 1000° C. or higher and 1350° C. or lower. The time for which the temperature is maintained is, for example, 0.5 hours or more and 8 hours or less.
　グリーンチップの焼成を行うことにより、グリーンシート中の有機バインダーが完全に除去されるとともに、セラミックの原料粉末が焼成されて、セラミック製の誘電体層１２が形成される。また、乾燥膜中の有機ビヒクルが除去されるとともに、導電性粉末が焼結もしくは溶融、一体化されて、内部電極層１１が形成され、誘電体層１２と内部電極層１１とが複数枚、交互に積層された積層セラミック焼成体が形成される。なお、酸素を誘電体層の内部に取り込んで信頼性を高めるとともに、内部電極の再酸化を抑制するとの観点から、焼成後の積層セラミック焼成体に対して、アニール処理を施してもよい。 By firing the green chip, the organic binder in the green sheet is completely removed, and the ceramic raw material powder is fired to form the ceramic dielectric layer 12 . In addition, the organic vehicle in the dry film is removed, and the conductive powder is sintered or melted and integrated to form the internal electrode layer 11, and the dielectric layer 12 and the internal electrode layer 11 are formed into a plurality of sheets, A laminated ceramic sintered body that is alternately laminated is formed. From the viewpoint of taking oxygen into the dielectric layers to improve reliability and suppressing reoxidation of the internal electrodes, the laminated ceramic sintered body after sintering may be annealed.
　そして、作製した積層セラミック焼成体に対して、一対の外部電極２０を設けることにより、積層セラミックコンデンサ１が製造される。例えば、外部電極２０は、外部電極層２１及びメッキ層２２を備える。外部電極層２１は、内部電極層１１と電気的に接続する。なお、外部電極２０の材料としては、例えば、銅やニッケル、またはこれらの合金が好適に使用できる。なお、電子部品は、積層セラミックコンデンサ以外の電子部品を用いることもできる。 Then, the multilayer ceramic capacitor 1 is manufactured by providing a pair of external electrodes 20 to the manufactured multilayer ceramic sintered body. For example, the external electrode 20 comprises an external electrode layer 21 and a plated layer 22 . The external electrode layers 21 are electrically connected to the internal electrode layers 11 . As the material of the external electrodes 20, for example, copper, nickel, or alloys thereof can be suitably used. Note that electronic components other than the laminated ceramic capacitor can be used as the electronic component.
　以下、本発明を実施例と比較例に基づき詳細に説明するが、本発明は実施例によって何ら限定されるものではない。 The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited by the examples.
［評価方法］
（導電性ペーストの粘度）
　導電性ペーストの粘度を、レオメーター（株式会社アントンパール・ジャパン製：レオメーターＭＣＲ３０２）を用いて測定した。粘度は、コーン角度１°、直径２５ｍｍのコーンプレートを用いて、ずり速度（せん断速度）１００ｓｅｃ－１の条件で測定した場合の値を用いた。 [Evaluation method]
(Viscosity of conductive paste)
The viscosity of the conductive paste was measured using a rheometer (manufactured by Anton Paar Japan Co., Ltd.: rheometer MCR302). The viscosity was measured using a cone plate with a cone angle of 1° and a diameter of 25 mm under conditions of shear rate (shear rate) of 100 sec −1 .
　また、導電性ペーストの粘度は、製造後１日時点及び１週間時点で測定され、１日時点の測定値を初期粘度とし、この初期粘度に対する１週間時点の測定値の比（１週間時点の測定値／１日時点の測定値）を経時増粘比として評価した。初期粘度は、０．２Ｐａ・ｓ以上１．２Ｐａ・ｓ未満を「〇」、１．２Ｐａ・ｓ以上を「×」と評価した。経時増粘比は、１．３未満を「〇」（粘度安定性が十分）と評価し、１．３以上を「×」（粘度安定性が不十分）とした。 In addition, the viscosity of the conductive paste is measured at 1 day and 1 week after production, the measured value at 1 day is defined as the initial viscosity, and the ratio of the measured value at 1 week to the initial viscosity (1 week at Measured value/measured value at 1 day) was evaluated as the thickening ratio over time. An initial viscosity of 0.2 Pa·s or more and less than 1.2 Pa·s was evaluated as "◯", and a value of 1.2 Pa·s or more was evaluated as "x". A viscosity increase ratio over time of less than 1.3 was evaluated as "good" (sufficient viscosity stability), and a time-dependent thickening ratio of 1.3 or more was evaluated as "poor" (insufficient viscosity stability).
（白浮き）
　作製直後の導電性ペースト２０ｇをガラス瓶（直径φ３０×高さ６５ｍｍ）中に室温にて静置し、１週間経過した後、導電性ペーストの外観を目視により観察し、白浮きが観察される割合を測定した。白浮きの割合（％）は、（白浮きの層の厚み／ペースト全体の量の厚み）＊１００で算出される。白浮きの割合（％）は、５％未満を「〇」（分離抑制効果が良好）、５％以上８％未満を「△」（分離抑制効果がある）、８％以上を「×」（分離抑制効果が不十分）と評価した。 (White floating)
20 g of the conductive paste immediately after preparation was left at room temperature in a glass bottle (diameter φ30 x height 65 mm), and after 1 week, the appearance of the conductive paste was visually observed, and the ratio of whitening observed. was measured. The ratio (%) of whitening is calculated by (thickness of layer of whitening/thickness of entire amount of paste)*100. The whitening ratio (%) is less than 5% with "○" (separation suppression effect is good), 5% or more and less than 8% with "△" (separation suppression effect), 8% or more with "X" ( Insufficient separation suppression effect).
［使用材料］
（導電性粉末）
　導電性粉末としては、Ｎｉ粉末（ＳＥＭ平均粒径０．３μｍ）を使用した。 [Materials used]
(Conductive powder)
Ni powder (SEM average particle size: 0.3 μm) was used as the conductive powder.
（セラミック粉末）
　セラミック粉末としては、チタン酸バリウム（ＢａＴｉＯ３；ＳＥＭ平均粒径０．１０μｍ）を使用した。 (ceramic powder)
Barium titanate (BaTiO 3 ; SEM average particle size 0.10 μm) was used as the ceramic powder.
（バインダー樹脂）
　バインダー樹脂としては、ポリビニルブチラール、エチルセルロース使用した。 (binder resin)
Polyvinyl butyral and ethyl cellulose were used as the binder resin.
（分散剤）
　分子量が５０００以上のカルボン酸系高分子分散剤１～４、カルボン酸系低分子分散剤１～２、及びアミン系高分子分散剤１を用いた。各分散剤の詳細を表１にまとめる。なお、カルボン酸系高分子分散剤４は、直鎖状のブロックポリマー構造を有する（くし型構造は有さない）。 (dispersant)
Carboxylic acid polymer dispersants 1 to 4, carboxylic acid low molecular dispersants 1 to 2, and amine polymer dispersant 1 having a molecular weight of 5000 or more were used. Details of each dispersant are summarized in Table 1. The carboxylic acid polymer dispersant 4 has a linear block polymer structure (does not have a comb structure).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（有機溶剤）
　有機溶剤としては、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ブチルカルビトール（ＢＣＡ）、ミネラルスピリット（ＭＡ）、ターピネオール（ＴＰＯ）、ジヒドロターピネオール（ＤＨＴ）、及び、ジヒドロターピニルアセテート（ＤＨＴＡ）、ジイソブチルケトン（ＤＩＢＫ）を使用した。 (Organic solvent)
Organic solvents include propylene glycol monobutyl ether (PNB), butyl carbitol (BCA), mineral spirits (MA), terpineol (TPO), dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), and diisobutyl ketone. (DIBK) was used.
［実施例１］
　導電性粉末５０質量％、セラミック粉末１２．５質量％、分散剤０．０５質量％（分散剤種：カルボン酸系高分子分散剤１）、バインダー樹脂２．５質量％（ポリビニルブチラール樹脂１．７質量％、エチルセルロース０．８質量％）、及び、残部として有機溶剤（溶剤１：残部、溶剤２：９．５質量％、溶剤３：７質量％）を添加して、全体として１００質量％となるよう配合した材料を準備した。これらの材料を混合分散処理して導電性ペーストを作製した。ここで、溶剤１はＤＨＴ、溶剤２はＰＮＢ、溶剤３はＭＡである。添加剤の詳細を含めた試験条件及び評価結果を表１に示す。 [Example 1]
50% by mass of conductive powder, 12.5% by mass of ceramic powder, 0.05% by mass of dispersant (dispersant type: carboxylic acid polymer dispersant 1), 2.5% by mass of binder resin (polyvinyl butyral resin 1. 7% by mass, ethyl cellulose 0.8% by mass), and an organic solvent as the balance (solvent 1: balance, solvent 2: 9.5% by mass, solvent 3: 7% by mass) to give a total of 100% by mass. A material blended so as to be was prepared. A conductive paste was prepared by mixing and dispersing these materials. Here, solvent 1 is DHT, solvent 2 is PNB, and solvent 3 is MA. Table 1 shows test conditions and evaluation results including details of additives.
［実施例２～１０、比較例１～３］
　分散剤種及び添加量、溶剤１～３を表１、２に示す通りに変更した以外は、実施例１と同様に導電性ペーストを作製して、評価した。なお、分散剤の添加量の違いによる配合割合は、溶剤１の添加量を調整することにより、導電性ペースト全体が１００質量％となるように調整した。分散剤の詳細を表１に、試験条件及び評価結果を表２に示す。
［実施例１１］
　有機溶剤の構成を４種含有に変更し、それぞれの含有量を（溶剤1：残部、溶剤２：５．３質量％、溶剤３：７質量％、溶剤４：４．２質量％）とした。溶剤１としてＤＨＴ、溶剤２としてＢＣＡ、溶剤３としてＭＳＡ、溶剤４としてＤＩＢＫを用いた以外は、実施例２と同様に導電性ペーストを作製して、評価した。分散剤の詳細を表１に、試験条件及び評価結果を表２に示す。 [Examples 2 to 10, Comparative Examples 1 to 3]
A conductive paste was prepared and evaluated in the same manner as in Example 1, except that the type and amount of dispersant added and the solvents 1 to 3 were changed as shown in Tables 1 and 2. The mixing ratio of the dispersant was adjusted by adjusting the amount of solvent 1 added so that the total amount of the conductive paste was 100% by mass. Details of the dispersant are shown in Table 1, and test conditions and evaluation results are shown in Table 2.
[Example 11]
The composition of the organic solvent was changed to contain four types, and the content of each was set to (solvent 1: balance, solvent 2: 5.3% by mass, solvent 3: 7% by mass, solvent 4: 4.2% by mass). . A conductive paste was prepared and evaluated in the same manner as in Example 2 except that DHT was used as solvent 1, BCA was used as solvent 2, MSA was used as solvent 3, and DIBK was used as solvent 4. Details of the dispersant are shown in Table 1, and test conditions and evaluation results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（評価結果）
　実施例の導電性ペーストは、分子量５０００以上のカルボン酸系高分子分散剤を含まない比較例１～３の導電性ペーストと比較して、経時的な粘度安定性が向上し、さらに保管により発生する白浮きの割合が十分小さく、分離抑制効果が向上することが分かる。 (Evaluation results)
Compared to the conductive pastes of Comparative Examples 1 to 3, which do not contain a carboxylic acid-based polymer dispersant having a molecular weight of 5000 or more, the conductive pastes of Examples have improved viscosity stability over time, and are generated during storage. It can be seen that the ratio of whitening that occurs is sufficiently small, and the effect of suppressing separation is improved.
　比較例１の導電性ペーストでは、くし型構造のカルボン酸系分散剤を用いているが、分子量が約８００と小さいため、微粒子の分散効果が不十分で、時間の経過にともない、グラビア印刷用の導電性ペーストとして、許容できないほどの粘度の増加が生じてしまっている。比較例２の導電性ペーストでは、低分子量のカルボン酸系分散剤を用いているが、粘度は十分に安定しているものの、白浮きの割合が許容量を超えてしまっている。比較例３の導電性ペーストでは、くし形構造を有する高分子系分散剤を用いているが吸着基がアミンであるため、初期粘度が高くグラビア印刷に適していない。 In the conductive paste of Comparative Example 1, a carboxylic acid-based dispersant with a comb-shaped structure is used. As a conductive paste, an unacceptable increase in viscosity has occurred. In the conductive paste of Comparative Example 2, a low-molecular-weight carboxylic acid-based dispersant is used, and although the viscosity is sufficiently stable, the percentage of whitening exceeds the allowable amount. The conductive paste of Comparative Example 3 uses a polymeric dispersant having a comb-shaped structure, but since the adsorption group is amine, the initial viscosity is high and it is not suitable for gravure printing.
　実施例２は、実施例１で用いたくし型のカルボン酸系高分子分散剤１の含有量を増やした試料であり、初期粘度、経時増粘比、白浮き量がより良好な結果が得られている。 Example 2 is a sample in which the content of the comb-shaped carboxylic acid-based polymer dispersant 1 used in Example 1 was increased, and better results were obtained in the initial viscosity, the ratio of thickening over time, and the amount of whitening. ing.
　実施例３、４は、実施例２で用いたくし型カルボン酸（Ｍｗ：５万）よりも平均分子量が小さいくし型カルボン酸（Ｍｗ：１～３万）を用いた試料である。実施例３，４の導電性ペーストでは、実施例２の導電性ペーストと比較して、白浮き量が若干増え、実施例４の導電性ペーストでは経時増粘比もより増えている。 Examples 3 and 4 are samples using a comb-shaped carboxylic acid (Mw: 10,000 to 30,000) having a smaller average molecular weight than the comb-shaped carboxylic acid (Mw: 50,000) used in Example 2. Compared with the conductive paste of Example 2, the conductive pastes of Examples 3 and 4 have a slightly increased amount of whitening, and the conductive paste of Example 4 has a higher viscosity increase ratio over time.
　また、実施例５の導電性ペーストはブロック重合型のカルボン酸系高分子分散剤を用いており、くし型構造のカルボン酸系高分子分散剤を用いた他の実施例よりもより多量添加することによって、他の実施例の場合と同程度の効果を発現できる。 In addition, the conductive paste of Example 5 uses a block polymerization type carboxylic acid-based polymer dispersant, and is added in a larger amount than other examples using a carboxylic acid-based polymer dispersant having a comb-shaped structure. By doing so, the same degree of effect as in other embodiments can be exhibited.
　実施例６および実施例７の導電性ペーストは、カルボン酸系くし型高分子分散剤と低分子量のカルボン酸系分散剤を組み合わせている。実施例６、７の導電性ペーストは、同種のくし型のカルボン酸系高分子分散剤を用いている実施例２の導電性ペーストと比較して、経時増粘比は同程度に低いが、若干、白浮き量が増加する。また、実施例６および実施例７の導電性ペーストは、実施例２のくし型のカルボン酸系高分子分散剤よりも平均分子量が小さい分散剤を用いた他の実施例（例：実施例４、５）の導電性ペーストと比較して、経時増粘比は低くなっているが、許容範囲内で白浮き量が増加傾向にある。 The conductive pastes of Examples 6 and 7 are a combination of a carboxylic acid-based comb-type polymer dispersant and a low-molecular-weight carboxylic acid-based dispersant. The conductive pastes of Examples 6 and 7 have a similarly low thickening ratio over time as compared with the conductive paste of Example 2, which uses the same comb-shaped carboxylic acid-based polymer dispersant. The amount of whitening increases slightly. Further, the conductive pastes of Examples 6 and 7 are other examples using a dispersant having a smaller average molecular weight than the comb-shaped carboxylic acid polymer dispersant of Example 2 (Example: Example 4 , 5), the thickening ratio over time is low, but the amount of whitening tends to increase within the allowable range.
　実施例８、９、１０および実施例１１の導電性ペーストは、実施例２の導電性ペーストにおける溶剤の種類を変更した試料である。溶剤の含有量が同じであっても、溶剤の種類の組み合わせを変えることで粘度や経時増粘比、白浮き量が多少変化しているが、大きく変わることはない。そのため、使用状況に合わせて、溶剤の種類の選定により粘度を微調整することが可能である。 The conductive pastes of Examples 8, 9, 10 and 11 are samples obtained by changing the type of solvent in the conductive paste of Example 2. Even if the content of the solvent is the same, the viscosity, the time-dependent thickening ratio, and the amount of whitening change slightly by changing the combination of the types of solvents, but they do not change significantly. Therefore, it is possible to finely adjust the viscosity by selecting the type of solvent according to the usage conditions.
　なお、本発明の技術範囲は、上述の実施形態などで説明した態様に限定されるものではない。上述の実施形態などで説明した要件の１つ以上は、省略されることがある。また、上述の実施形態などで説明した要件は、適宜組み合わせることができる。また、法令で許容される限りにおいて、上述の実施形態などで引用した全ての文献の開示を援用して本文の記載の一部とする。また、法令で許容される限りにおいて、日本特許出願である特願２０２１－１４４２９４の内容を援用して本文の記載の一部とする。 It should be noted that the technical scope of the present invention is not limited to the aspects described in the above embodiments. One or more of the requirements described in the above embodiments and the like may be omitted. Also, the requirements described in the above-described embodiments and the like can be combined as appropriate. In addition, as long as it is permitted by laws and regulations, the disclosure of all the documents cited in the above-described embodiments and the like is used as part of the description of the text. In addition, as long as it is permitted by law, the contents of Japanese Patent Application No. 2021-144294 are used as part of the description of the text.
　本発明の導電性ペーストは、グラビア印刷に適した粘度を長期間にわたり安定的に有し、かつ、導電性粉末とセラミック粉末との分離を十分に抑制できる。よって、本発明の導電性ペーストは、特に携帯電話やデジタル機器などの小型化が進む電子機器のチップ部品である積層セラミックコンデンサの内部電極用の原料として好適に用いることができる。また、本発明の導電性ペーストは、グラビア印刷用の導電性ペーストとして好適に用いることができる。 The conductive paste of the present invention stably has a viscosity suitable for gravure printing over a long period of time, and can sufficiently suppress separation between the conductive powder and the ceramic powder. Therefore, the conductive paste of the present invention can be suitably used as a raw material for internal electrodes of laminated ceramic capacitors, which are chip components of electronic devices such as mobile phones and digital devices, which are becoming increasingly compact. Moreover, the conductive paste of the present invention can be suitably used as a conductive paste for gravure printing.
１　　　　積層セラミックコンデンサ
１０　　　セラミック積層体
１１　　　内部電極層
１２　　　誘電体層
２０　　　外部電極
２１　　　外部電極層
２２　　　メッキ層 1 laminated ceramic capacitor 10 ceramic laminate 11 internal electrode layer 12 dielectric layer 20 external electrode 21 external electrode layer 22 plating layer

Claims (17)

  1. 　導電性粉末、セラミック粉末、分散剤、バインダー樹脂及び有機溶剤を含むグラビア印刷用導電性ペーストであって、
    　前記分散剤は、重量平均分子量が５０００以上であるカルボン酸系高分子分散剤を含み、
    　前記カルボン酸系高分子分散剤を、導電性ペースト全体に対して０．０１質量％以上２．０質量％未満含む、グラビア印刷用導電性ペースト。     A conductive paste for gravure printing containing a conductive powder, a ceramic powder, a dispersant, a binder resin and an organic solvent,
    The dispersant contains a carboxylic acid polymer dispersant having a weight average molecular weight of 5000 or more,
    A conductive paste for gravure printing, containing 0.01% by mass or more and less than 2.0% by mass of the carboxylic acid-based polymer dispersant relative to the entire conductive paste.
  2. 　前記カルボン酸系高分子分散剤の酸価が５０ｍｇＫＯＨ／ｇ以上２５０ｍｇＫＯＨ／ｇ以下である、請求項１に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to claim 1, wherein the carboxylic acid polymer dispersant has an acid value of 50 mgKOH/g or more and 250 mgKOH/g or less.
  3. 　前記カルボン酸系高分子分散剤がくし型構造及び／又はブロックポリマー構造を有する高分子系分散剤を含む、請求項１又は請求項２に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to claim 1 or 2, wherein the carboxylic acid-based polymer dispersant contains a polymer-based dispersant having a comb structure and/or a block polymer structure.
  4. 　前記くし型構造を有する高分子系分散剤がアルキレンオキシド重合体を含有する構成のグラフト鎖を有する、請求項３に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to claim 3, wherein the polymeric dispersant having a comb structure has a graft chain containing an alkylene oxide polymer.
  5. 　前記有機溶剤がジヒドロターピネオール（ＤＨＴ）、ジヒドロターピニルアセテート（ＤＨＴＡ）、ターピネオール（ＴＰＯ）、プロピレングリコールモノブチルエーテル（ＰＮＢ）、ジエチレングリコールモノブチルエーテルアセテート（ＢＣＡ）、およびジイソブチルケトン（ＤＩＢＫ）からなる群より選ばれる１種類以上を含む、請求項１～４のいずれか一項に記載のグラビア印刷用導電性ペースト。 the organic solvent is selected from the group consisting of dihydroterpineol (DHT), dihydroterpinyl acetate (DHTA), terpineol (TPO), propylene glycol monobutyl ether (PNB), diethylene glycol monobutyl ether acetate (BCA), and diisobutyl ketone (DIBK); The conductive paste for gravure printing according to any one of claims 1 to 4, comprising one or more selected types.
  6. 　前記カルボン酸系高分子分散剤の含有量が、分散剤全量に対して６０質量％以上である請求項１～５のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 5, wherein the content of the carboxylic acid polymer dispersant is 60% by mass or more with respect to the total amount of the dispersant.
  7. 　前記分散剤は、分子量が５０００未満であるカルボン酸系分散剤を、分散剤全量に対して、０質量％以上６０質量％以下含む、請求項１～６のいずれか一項に記載のグラビア印刷用導電性ペースト。 The dispersant contains a carboxylic acid-based dispersant having a molecular weight of less than 5000, with respect to the total amount of the dispersant, 0% by mass or more and 60% by mass or less, gravure printing according to any one of claims 1 to 6 for conductive paste.
  8. 　前記導電性粉末は、Ｎｉ、Ｐｄ、Ｐｔ、Ａｕ、Ａｇ、Ｃｕ及びこれらの合金から選ばれる１種以上の金属粉末を含む請求項１～７のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive powder for gravure printing according to any one of claims 1 to 7, wherein the conductive powder contains one or more metal powders selected from Ni, Pd, Pt, Au, Ag, Cu and alloys thereof. paste.
  9. 　前記導電性粉末は、平均粒径が０．０５μｍ以上１．０μｍ以下である請求項１～８のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 8, wherein the conductive powder has an average particle size of 0.05 µm or more and 1.0 µm or less.
  10. 　前記セラミック粉末は、チタン酸バリウムを含む請求項１～９のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 9, wherein the ceramic powder contains barium titanate.
  11. 　前記セラミック粉末は、平均粒径が０．０１μｍ以上０．５μｍ以下である請求項１～１０のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 10, wherein the ceramic powder has an average particle size of 0.01 µm or more and 0.5 µm or less.
  12. 　前記セラミック粉末は、導電性ペースト全体に対して１質量％以上２０質量％以下含まれる請求項１～１１のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 11, wherein the ceramic powder is contained in an amount of 1% by mass or more and 20% by mass or less with respect to the entire conductive paste.
  13. 　前記バインダー樹脂が、セルロース系樹脂を含む請求項１～１２のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 12, wherein the binder resin contains a cellulose resin.
  14. 　積層セラミック部品の内部電極用である請求項１～１３のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 13, which is for internal electrodes of laminated ceramic parts.
  15. 　ずり速度１００ｓｅｃ－１での粘度が１．２Ｐａ・Ｓ以下である、請求項１～１４のいずれか一項に記載のグラビア印刷用導電性ペースト。 The conductive paste for gravure printing according to any one of claims 1 to 14, which has a viscosity of 1.2 Pa·S or less at a shear rate of 100 sec -1 .
  16. 　請求項１～１５のいずれか一項に記載のグラビア印刷用導電性ペーストを用いて形成された、電子部品。 An electronic component formed using the conductive paste for gravure printing according to any one of claims 1 to 15.
  17. 　誘電体層と内部電極層とを積層した積層体を少なくとも有し、
    　前記内部電極層は、請求項１～１５のいずれか一項に記載のグラビア印刷用導電性ペーストを用いて形成される、積層セラミックコンデンサ。     Having at least a laminated body in which dielectric layers and internal electrode layers are laminated,
    A laminated ceramic capacitor, wherein the internal electrode layers are formed using the conductive paste for gravure printing according to any one of claims 1 to 15.
PCT/JP2022/033197 2021-09-03 2022-09-02 Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor WO2023033163A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020247008662A KR20240049576A (en) 2021-09-03 2022-09-02 Conductive paste for gravure printing, electronic components, and multilayer ceramic capacitors
CN202280059331.5A CN117897781A (en) 2021-09-03 2022-09-02 Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-144294 2021-09-03
JP2021144294A JP2023037498A (en) 2021-09-03 2021-09-03 Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor

Publications (1)

Publication Number Publication Date
WO2023033163A1 true WO2023033163A1 (en) 2023-03-09

Family

ID=85412416

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/033197 WO2023033163A1 (en) 2021-09-03 2022-09-02 Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor

Country Status (5)

Country Link
JP (1) JP2023037498A (en)
KR (1) KR20240049576A (en)
CN (1) CN117897781A (en)
TW (1) TW202317712A (en)
WO (1) WO2023033163A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012174797A (en) * 2011-02-18 2012-09-10 Sumitomo Metal Mining Co Ltd Conductive paste for photogravure used for multilayer ceramic capacitor internal electrode
WO2019181875A1 (en) * 2018-03-19 2019-09-26 株式会社ノリタケカンパニーリミテド Conductive paste having stable viscosity over time
WO2021020557A1 (en) * 2019-07-31 2021-02-04 住友金属鉱山株式会社 Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2021059925A1 (en) * 2019-09-25 2021-04-01 株式会社ノリタケカンパニーリミテド Electroconductive paste and method for producing electronic component using same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4389431B2 (en) 2001-12-13 2009-12-24 株式会社村田製作所 Conductive paste for gravure printing, method for producing the same, and multilayer ceramic electronic component
JP2003187638A (en) 2001-12-20 2003-07-04 Murata Mfg Co Ltd Conductive paste for gravure printing and its manufacturing method as well as laminated ceramic electronic component

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012174797A (en) * 2011-02-18 2012-09-10 Sumitomo Metal Mining Co Ltd Conductive paste for photogravure used for multilayer ceramic capacitor internal electrode
WO2019181875A1 (en) * 2018-03-19 2019-09-26 株式会社ノリタケカンパニーリミテド Conductive paste having stable viscosity over time
WO2021020557A1 (en) * 2019-07-31 2021-02-04 住友金属鉱山株式会社 Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2021059925A1 (en) * 2019-09-25 2021-04-01 株式会社ノリタケカンパニーリミテド Electroconductive paste and method for producing electronic component using same

Also Published As

Publication number Publication date
TW202317712A (en) 2023-05-01
CN117897781A (en) 2024-04-16
KR20240049576A (en) 2024-04-16
JP2023037498A (en) 2023-03-15

Similar Documents

Publication Publication Date Title
WO2021106470A1 (en) Electroconductive paste for gravure printing, electronic component, and laminated ceramic capacitor
CN113227246B (en) Conductive paste, electronic component, and multilayer ceramic capacitor
CN112334995B (en) Conductive paste, electronic component, and multilayer ceramic capacitor
JP7279643B2 (en) Conductive paste, electronic parts, and laminated ceramic capacitors
CN111052263B (en) Conductive paste, electronic component, and multilayer ceramic capacitor
CN113227233B (en) Conductive paste, electronic component, and multilayer ceramic capacitor
CN111902882B (en) Conductive paste, electronic component, and multilayer ceramic capacitor
JP7279642B2 (en) Conductive paste, electronic parts, and laminated ceramic capacitors
WO2021020557A1 (en) Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2023033163A1 (en) Conductive paste for gravure printing, electronic component, and multilayer ceramic capacitor
CN111066098A (en) Conductive paste, electronic component, and multilayer ceramic capacitor
CN111095439A (en) Conductive paste, electronic component, and multilayer ceramic capacitor
JP2022070803A (en) Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2024024534A1 (en) Carboxy group-containing polymer dispersant, electroconductive paste, electronic component, and laminated ceramic capacitor
WO2022255467A1 (en) Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2022092045A1 (en) Conductive paste for gravure printing, electronic component, and laminate ceramic capacitor
WO2023190613A1 (en) Conductive paste, electronic component, and multilayer ceramic capacitor
TW202411411A (en) Polymer dispersants containing carboxyl groups, conductive pastes, electronic components and laminated ceramic capacitors

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22864745

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 202280059331.5

Country of ref document: CN

ENP Entry into the national phase

Ref document number: 20247008662

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE