Conductive paste, electronic components, and multilayer ceramic capacitors

Abstract

Provided is a conductive paste which can further improve adhesion to a substrate.　This conductive paste comprises a conductive powder, a binder resin, an additive, and an organic solvent, wherein the glass transition point of a dried body, which is obtained by mixing a binder resin, an additive, and an organic solvent in the same proportion as in the conductive paste and then drying the mixture, is 30°C to 55°C.

Description

[Technical Field]

[0001] This invention relates to conductive paste, electronic components, and multilayer ceramic capacitors. [Background technology]

[0002] With the miniaturization and increased performance of electronic devices such as mobile phones and digital equipment, there is a demand for smaller and higher-capacitance electronic components, including multilayer ceramic capacitors. Multilayer ceramic capacitors have a structure in which multiple dielectric layers and multiple internal electrode layers are alternately stacked, and miniaturization and increased capacitance can be achieved by thinning these dielectric layers and internal electrode layers.

[0003] Multilayer ceramic capacitors are manufactured, for example, as follows: First, a conductive paste for internal electrodes is printed in a predetermined electrode pattern onto the surface of a green sheet containing dielectric powder such as barium titanate (BaTiO3) and a binder resin, and then dried to form a dry film (conductive film). Next, the dry film and the green sheet are stacked alternately to obtain a laminate. Then, this laminate is heated and compressed to form a bonded body. This bonded body is cut, subjected to a de-organic binder treatment in an oxidizing or inert atmosphere, and then fired to obtain a fired chip. Next, paste for external electrodes is applied to both ends of the fired chip, and after firing, nickel plating or the like is applied to the surface of the external electrodes to obtain a multilayer ceramic capacitor.

[0004] In the process of heat-pressing and cutting a laminate formed by stacking a dried film and a green sheet, if the adhesion between the dried film and the green sheet (substrate) is insufficient, the dried film (conductive film) may peel off from the green sheet (substrate), or the layer structure may shift, resulting in a multilayer ceramic capacitor that does not have the desired electrical characteristics.

[0005] For example, Patent Document 1 discloses a conductive paste comprising a (meth)acrylic resin as a binder resin, an organic solvent, and a metal powder, for the purpose of improving the adhesion of a conductive paste containing a (meth)acrylic resin as a binder resin to a ceramic green sheet, wherein the (meth)acrylic resin has a glass transition temperature Tg in the range of -60°C to 120°C, a hydroxyl group content in the molecule in the range of 0.01% to 5% by mass, an acid value in the range of 1 mg KOH / g to 50 mg KOH / g, and a weight-average molecular weight in the range of 10,000 Mv to 350,000 Mv.

[0006] Furthermore, Patent Document 2 discloses a conductive paste for forming an electrode layer on a substrate, with the aim of providing a conductive paste that can form a conductive film with excellent adhesion to a substrate, comprising a conductive powder, a resin binder, an organic additive, and an organic solvent, wherein the organic additive contains a (meth)acrylate compound having two or more (meth)acryloyl groups in one molecule and a number average molecular weight of 1000 or less.

[0007] Furthermore, Patent Document 3 discloses a drying film for internal electrodes of a multilayer ceramic capacitor, which is formed from a composition containing conductive powder and an organic binder resin, with the aim of providing a drying film for internal electrodes that has excellent adhesion to the dielectric layer and can form internal electrodes whose shape does not change significantly before and after heat treatment, and is characterized in that it has a Vickers hardness of 47 Hv or more and 51 Hv or less. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2013 / 187183 [Patent Document 2] Japanese Patent Publication No. 2018-055933 [Patent Document 3] Japanese Patent Publication No. 2019-121744

Summary of the Invention

Problems to be Solved by the Invention

[0009] In recent years, from the viewpoints of improving productivity and reducing costs, when heat-pressing a laminate obtained by alternately laminating a dry film and a ceramic green sheet in the manufacturing process of a multilayer ceramic capacitor, the pressing time during pressing may be shortened or the pressure may be reduced.

[0010] However, when the pressing time during pressing is shortened or the pressure is reduced, sufficient adhesion cannot be obtained between the dry film and the base material with a conventional conductive paste, resulting in displacement of the dry film and possibly a decrease in the yield. Therefore, there is a need for a conductive paste that can further improve the adhesion to the base material when forming the dry film.

[0011] In view of such a situation, an object of the present invention is to provide a conductive paste that can further improve the adhesion to a base material.

Means for Solving the Problems

[0012] In a first aspect of the present invention, there is provided a conductive paste containing conductive powder, a binder resin, an additive, and an organic solvent, wherein the glass transition point of a dried body obtained by mixing the binder resin, the additive, and the organic solvent at the same content ratio as the conductive paste and then drying is 30°C or higher and 55°C or lower.

[0013] Furthermore, the above additive contains a compound that can lower the glass transition temperature of the dried product, and it is preferable that the compound is present in an amount of 0.01% to 2.0% by mass relative to the entire conductive paste. Furthermore, it is preferable that the temperature at which the weight loss rate in thermogravimetric analysis is maximized for the above compound is 200°C or higher. Furthermore, it is preferable that the molecular weight of the above compound is 250 to 3000. The conductive paste further preferably contains an acidic dispersant and / or a basic dispersant. Furthermore, the conductive powder preferably contains at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu and their alloys. Furthermore, it is preferable that the conductive powder has an average particle size of 0.05 μm to 1.0 μm. Furthermore, it is preferable that the binder resin contains a butyral-based resin. Furthermore, the conductive paste further preferably contains ceramic powder. Furthermore, it is preferable that the ceramic powder contains barium titanate. Furthermore, it is preferable that the ceramic powder has an average particle size of 0.01 μm to 0.5 μm. Furthermore, it is preferable that the ceramic powder is contained in an amount of 1% to 20% by mass relative to the total amount of conductive paste. It is also preferable that the conductive paste is used for internal electrodes of multilayer ceramic components.

[0014] In a second aspect of the present invention, an electronic component formed using the conductive paste described above is provided.

[0015] A third aspect of the present invention provides a multilayer ceramic capacitor having at least a laminate in which a dielectric layer and an internal electrode layer are stacked, wherein the internal electrode layer is formed using the conductive paste described above. [Effects of the Invention]

[0016] The conductive paste of the present invention can further improve adhesion to the substrate. Furthermore, in the manufacturing process of multilayer ceramic capacitors, the dried film (internal electrode layer) formed using the conductive paste of the present invention has high adhesion to the green sheet (dielectric layer). [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a perspective view and a cross-sectional view showing a multilayer ceramic capacitor according to an embodiment. [Modes for carrying out the invention]

[0018] 1. Conductive paste The inventors of this invention conducted extensive research to further improve the adhesion between the conductive paste and the substrate, and discovered a correlation between the glass transition temperature of the components contained in the conductive paste and the adhesion to the substrate. In other words, the conductive paste according to this embodiment contains conductive powder, a binder resin, additives, and an organic solvent, and by controlling the glass transition temperature of the components contained in the conductive paste to a specific range, the adhesion to the substrate (e.g., a green sheet) can be further improved. The characteristics of the conductive paste according to this embodiment will be described below.

[0019] [Glass transition temperature] When conductive pastes contain powder materials such as conductive powder, it is difficult to accurately measure the glass transition temperature due to the influence of the powder material. Therefore, in order to evaluate the glass transition temperature of the components contained in conductive pastes, the inventors measured the glass transition temperature Tg of a dried paste (for evaluation) prepared from a composition of components other than powder materials that exhibit glass transition behavior.

[0020] A dried sample for evaluating the glass transition temperature (Tg) can be prepared, for example, by the following method: The binder resin, additives, and organic solvent (i.e., components excluding powder materials such as conductive powder) contained in the conductive paste are weighed in the same proportions as in the conductive paste, mixed at 2000 rpm for 4 minutes using a self-rotating mixer (Sinky, ARE-310), and the resulting liquid is applied to a PET film with an applicator to a wet film thickness of 254 μm. The sample is dried at 120°C for 40 minutes to remove the organic solvent and obtain a sample for evaluation.

[0021] The glass transition temperature (Tg) of the dried material (for evaluation) is between 30°C and 55°C, preferably between 30°C and 50°C. By controlling the glass transition temperature of the dried material (for evaluation) within the above range, the adhesion between the dried film and the green sheet is improved. Although the detailed reason for this is unclear, it is thought that by setting the glass transition temperature (Tg) within a specific range, the dried film obtained using the conductive paste according to this embodiment is moderately softened, making it easier for entanglement to occur at the adhesive interface, thereby improving the adhesion between the dried film and the ceramic green sheet (dielectric layer).

[0022] When the conductive paste contains two or more types of resins as binder resins, multiple glass transition temperatures (Tg) may be measured depending on the resins included. However, the glass transition temperature (Tg) of the evaluation sample in this specification represents the glass transition temperature (Tg) in the lowest temperature range. Furthermore, the glass transition temperature (Tg) of the dried body (evaluation sample) can be measured by the method described in the examples. As an evaluation sample, a dried body obtained by manufacturing the conductive paste, centrifuging the conductive paste to remove fillers (powdered materials such as conductive powder), and then drying it may be used.

[0023] [Vickers hardness (room temperature)] Furthermore, when the conductive paste in this embodiment is applied to the surface of a substrate and dried at 75°C for 20 minutes to form a dried film, the Vickers hardness of the surface of the dried film at room temperature is preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less. The lower limit of the Vickers hardness (room temperature) is, for example, 3.5 or higher.

[0024] [Vickers hardness (60℃)] The Vickers hardness of the surface of the dried film at 60°C is preferably 8 or less, more preferably 7 or less, and even more preferably 6 or less. The lower limit of the Vickers hardness (60°C) is, for example, 3 or more. When measuring the Vickers hardness (60°C) of the dried film, it is desirable to pre-condition the film by leaving it at 60°C for 3 minutes.

[0025] [Components] The conductive paste according to this embodiment comprises conductive powder, a binder resin, an additive, and an organic solvent. The conductive paste may further contain ceramic powder. The glass transition temperature of the dried product (for evaluation) can be controlled within the above range by appropriately adjusting, for example, the type and content of the binder resin, additive, and organic solvent. The specific components will be described in detail below.

[0026] (conductive powder) The conductive powder is not particularly limited, and metal powders can be used. For example, one or more powders selected from Ni, Pd, Pt, Au, Ag, Cu, and their alloys can be used. Among these, Ni or its alloy powder (hereinafter sometimes referred to as "Ni powder") is preferred from the viewpoint of conductivity, corrosion resistance, and cost. As a Ni alloy, for example, an alloy of Ni with 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. The Ni content 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 several hundred ppm of element S in order to suppress the rapid generation of gas due to the partial thermal decomposition of the binder resin during the debindering process.

[0027] The average particle size of the conductive powder is preferably 0.05 μm to 1.0 μm, and more preferably 0.1 μm to 0.5 μm. When the average particle size of the conductive powder is within the above range, it can be suitably used as a paste for the internal electrodes of thin-film multilayer ceramic capacitors (multilayer ceramic components). The average particle size is a value obtained from observation using a scanning electron microscope (SEM), and is the average value obtained by measuring the particle size of multiple individual particles from an image observed with an SEM at a magnification of 10,000x (SEM average particle size).

[0028] The conductive powder content is preferably 30% by mass or more and less than 70% by mass, and more preferably 40% by mass or more and 60% by mass or less, relative to the total conductive paste. When the conductive powder content is within the above range, the conductivity and dispersibility are excellent.

[0029] (Ceramic powder) The ceramic powder is not particularly limited, and for example, in the case of a paste for the internal electrodes of a multilayer ceramic capacitor, a known ceramic powder can be appropriately selected depending on the type of multilayer ceramic capacitor to be used. As the ceramic powder, for example, a perovskite-type oxide containing Ba and Ti can be used, and preferably contains barium titanate (BaTiO3).

[0030] As the ceramic powder, a ceramic powder mainly composed of barium titanate and containing oxides as minor components may be used. Examples of oxides include oxides of Mn, Cr, Si, Ca, Ba, Mg, V, W, Ta, Nb, and one or more rare earth elements. Alternatively, as the ceramic powder, a perovskite-type oxide ferroelectric ceramic powder may be used, in which the Ba or Ti atoms of barium titanate (BaTiO3) are substituted with other atoms, such as Sn, Pb, or Zr.

[0031] When used as a conductive paste for internal electrodes, the ceramic powder may have the same composition as the dielectric ceramic powder that constitutes the green sheet of a multilayer ceramic capacitor (electronic component). This suppresses crack generation due to a mismatch in shrinkage at the interface between the dielectric layer and the internal electrode layer during the sintering process. Examples of such ceramic powders include oxides such as ZnO, ferrite, PZT, BaO, Al2O3, Bi2O3, R(rare earth element)2O3, TiO2, and Nd2O3. One type of ceramic powder may be used, or two or more types may be used.

[0032] The average particle size of the ceramic powder is, for example, 0.01 μm to 0.5 μm, preferably in the range of 0.01 μm to 0.3 μm. Because the average particle size of the ceramic powder is within this range, when used as a paste for internal electrodes, it is possible to form sufficiently fine, thin, and uniform internal electrodes. The average particle size is determined from observation using a scanning electron microscope (SEM), and is the average value obtained by measuring the particle size of multiple individual particles from an image observed at a magnification of 50,000x with an SEM (SEM average particle size).

[0033] The ceramic powder content is preferably 1% to 20% by mass, and more preferably 3% to 15% by mass, relative to the total conductive paste. When the ceramic powder content is within the above range, the dispersibility and sinterability are excellent.

[0034] Furthermore, the ceramic powder content is preferably 1 to 30 parts by mass, and more preferably 3 to 30 parts by mass, per 100 parts by mass of conductive powder.

[0035] (Binder resin) The binder resin preferably contains a butyral-based resin. Furthermore, when used as a paste for internal electrodes, a butyral-based resin may be included, or a butyral-based resin may be used alone, from the viewpoint of improving the adhesive strength with the green sheet. An example of a butyral-based resin is polyvinyl butyral (PVB). When the conductive paste contains a butyral-based resin, the adhesive strength with the green sheet can be further improved.

[0036] The lower limit of the butyral resin content is not particularly limited, but for example, it may be 20% by mass or more, 40% by mass or more, more than 50% by mass or 60% by mass or more, relative to the total binder resin. When the butyral resin content is within the above range, the adhesion is further improved, and the adhesive strength between the dried film and the green sheet (substrate) is improved.

[0037] Furthermore, there is no particular upper limit to the butyral resin content; for example, it may be 90% by mass or less, or 80% by mass or less, relative to the total binder resin. When the butyral resin content is within the above range, the conductive paste has an appropriate hardness, making it less likely for problems such as the printed film peeling off the support film or the electrodes being crushed during heat-pressing to occur.

[0038] Furthermore, the weight-average molecular weight (Mw) of the butyral resin may be between 30,000 and 300,000, between 50,000 and 200,000, or between 100,000 and 150,000. The glass transition temperature (Tg) of the butyral resin may be between 50°C and 90°C, or between 60°C and 80°C. By including the additives described later in combination with the butyral resin having the above characteristics, a conductive paste with improved adhesion can be obtained. Note that the butyral resin may be included alone or in combination of two or more types.

[0039] Furthermore, resins other than butyral-based resins may be included as binder resins. The binder resins other than those mentioned above are not particularly limited, and known resins can be used, such as cellulose-based resins like methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, and nitrocellulose, and acrylic resins. Among these, from the viewpoint of solubility in solvents and combustion decomposition, the inclusion of cellulose-based resins is preferable, and the inclusion of ethylcellulose is more preferable.

[0040] For example, when a cellulose-based resin is included as a binder resin, the weight-average molecular weight (Mw) may be between 10,000 and 300,000. Furthermore, the hydroxyl value of the cellulose-based resin is not particularly limited, but is preferably between 0.1 mg KOH / g and 15 mg KOH / g. Note that the cellulose-based resin may be included alone or in combination of two or more types.

[0041] Furthermore, when the binder resin contains cellulose-based resin and butyral-based resin, from the viewpoint of improving adhesion, the butyral-based resin may be included in an amount of 20% by mass or more, 40% by mass or more, more than 50% by mass or more, or 60% by mass or more, relative to the total content (100% by mass) of cellulose-based resin and butyral-based resin. When the content of both resins is within the above range, adhesion is further improved, and the adhesive strength between the dried film and the green sheet (substrate) may be improved. Also, there is no particular upper limit to the content of butyral-based resin; it may be less than 100% by mass, 90% by mass or less, or 80% by mass or less. When the content of both resins is within the above range, the conductive paste can have an appropriate hardness, and problems such as the printed film not peeling off the support film or the electrodes being crushed during heat-pressing are less likely to occur.

[0042] The binder resin content is preferably 0.5% to 10% by mass, and more preferably 1% to 7% by mass, relative to the total conductive paste. When the binder resin content is within the above range, the conductivity and dispersibility are excellent.

[0043] The binder resin content is preferably 1 to 20 parts by mass, and more preferably 1 to 14 parts by mass, per 100 parts by mass of conductive powder.

[0044] (Organic solvents) 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 solvents, acetate solvents, ether solvents, and ketone solvents.

[0045] Examples of terpene solvents include terpineol, dihydroterpineol, and dihydroterpinyl acetate.

[0046] Examples of acetate-based solvents include isobornyl acetate, isobornyl propinate, isobornyl butyrate and isobornyl isobutyrate, glycol ether acetates such as ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxypropyl-2-acetate, glycol diacetates such as propylene glycol diacetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, and 1,6-hexanediol diacetate, and cyclohexanol acetate.

[0047] Examples of ether-based solvents include propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; ethylene glycol ethers such as diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monohexyl ether, and ethylene glycol monohexyl ether; dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl-n-butyl ether, and dipropylene glycol dimethyl ether.

[0048] Examples of ketone-based solvents include methyl isobutyl ketone and diisobutyl ketone. When a ketone-based solvent is included, viscosity can be adjusted without impairing dispersibility, and drying properties can be improved.

[0049] The organic solvent preferably contains at least one selected from the group consisting of terpineol, dihydroterpineol, dihydroterpinyl acetate, propylene glycol monobutyl ether, and diethylene glycol monobutyl ether acetate. The inclusion of these organic solvents results in excellent compatibility with the binder resin and excellent dispersibility of the filler.

[0050] The content of the organic solvent (total) is preferably 20% to 60% by mass, and more preferably 25% to 45% by mass, relative to the total amount of conductive paste. When the content of the organic solvent is within the above range, the conductivity and dispersibility are excellent.

[0051] The content of the organic solvent is preferably 50 parts by mass to 130 parts by mass, and more preferably 60 parts by mass to 90 parts by mass, per 100 parts by mass of conductive powder. When the content of the organic solvent is within the above range, the conductivity and dispersibility are excellent.

[0052] Furthermore, one type of organic solvent may be used, or two or more types may be used. For example, if two or more types of organic solvents are included, at least one selected from the group consisting of terpineol, dihydroterpineol, dihydroterpinyl acetate, propylene glycol monobutyl ether (PNB), and diethylene glycol monobutyl ether acetate may be included, along with a hydrocarbon solvent. In addition, at least one selected from methyl isobutyl ketone and diisobutyl ketone may be included in combination with these organic solvents.

[0053] Examples of hydrocarbon solvents include solvents containing tridecane, nonane, cyclohexane, mineral spirits, and naphthenic solvents. Among these, the inclusion of mineral spirits is preferred. The content of the hydrocarbon solvent may be 10% to 50% by mass or 20% to 40% by mass relative to the total organic solvent.

[0054] (Additives) The conductive paste according to this embodiment includes an additive. Preferably, the additive includes a compound that can lower the glass transition temperature of the dried product (for evaluation) to a specific range.

[0055] The above-mentioned compounds are not particularly limited as long as the glass transition temperature Tg of the dried product can be adjusted to a specific range, but for example, at least one compound selected from the group consisting of compounds having an ester structure, compounds having an amide structure, compounds having a phosphate group, and compounds having a rosin skeleton is preferred, and among these, compounds having an ester structure, compounds having an amide structure, and compounds having a phosphate group are more preferred.

[0056] The above compound is thought to be able to adjust the glass transition temperature of the dried film to a specific range by inhibiting the interaction between the resins contained in the conductive paste. Furthermore, it is thought that the addition of the above compound moderately softens the dried film, and this softening makes the surface of the dried film more deformable, which increases the contact area with the adherend during bonding. Because the interaction of the resins is inhibited, entanglement at the adhesive interface is more likely to occur, thus improving the adhesion between the dried film and the ceramic green sheet (dielectric layer).

[0057] Furthermore, the above compound is preferably one in which the glass transition temperature Tg of the dried product (for evaluation) is compared with the glass transition temperature Tg' of the dried product (for evaluation) that does not contain the above compound, preferably 10°C or higher, and more preferably 13°C. That's all. More preferably, a compound can be selected that can lower the temperature by 15°C or more, and even more preferably by 20°C or more.

[0058] Furthermore, the above compound preferably has a maximum thermal decomposition temperature at which the weight loss rate in thermogravimetric analysis is maximized (maximum thermal decomposition temperature), which may be, for example, 200°C or higher, 220°C or higher, or 250°C or higher. When the maximum thermal decomposition temperature is within the above range, delamination and cracking of the laminate can be suppressed. The upper limit of the maximum thermal decomposition temperature is not particularly limited, but may be, for example, 450°C or lower, 400°C or lower, or 350°C or lower.

[0059] The maximum pyrolysis temperature is determined by thermogravimetric (TG) measurement using the following method: Using a pyrolysis gravimetric analyzer (NETC STA25000REGULUS), the temperature is increased from 20°C to 550°C at a heating rate of 5°C / min under a nitrogen atmosphere, and the weight loss during this process is measured. The temperature at which the differential heating loss is greatest is defined as the maximum pyrolysis temperature.

[0060] The following describes specific examples of compounds whose glass transition temperature in the dried product (for evaluation) can be reduced to a specific range.

[0061] (a) Compounds having an ester structure The compounds having an ester structure preferably include compounds having a structural part shown in the following formula (A) or formula (B) (hereinafter also referred to as "ester compounds").

[0062] [ka] (However, R 1 (This represents a saturated or unsaturated aliphatic hydrocarbon group having 2 to 12 carbon atoms, and the aliphatic hydrocarbon group may be linear or branched, and one or more methylene (-CH2-) atoms in the aliphatic hydrocarbon group may be replaced by oxygen (-O-).)

[0063] The ester compound more preferably has the structure shown in the following structural formula (1) or structural formula (2). [ka]

[0064] In the above equations (1) and (2), R 1 , R 2 , R 3Each independently represents a saturated or unsaturated aliphatic hydrocarbon group having 2 to 12 carbon atoms. The aliphatic hydrocarbon group may be linear or branched, and one or more methylene (-CH2-) groups contained in the aliphatic hydrocarbon group may be substituted with oxygen (-O-). Note that R 1 and R 2 and R 3 include the number of carbon atoms of the methylene (-CH2-) substituted with oxygen (-O-).

[0065] In the above formulas (1) and (2), the lower limit of the number of carbon atoms of R 1 and R 3 may each independently be 3 or more, or may be 5 or more. Also, the upper limit of the number of carbon atoms of R 1 and R 3 may each independently be 10 or less, or may be 8 or less. Also, the number of carbon atoms of R 1 and R 3 may be the same.

[0066] Also, R 1 and R 3 may be an unsubstituted aliphatic hydrocarbon group, for example, one methylene (-CH2-) may be substituted with oxygen (-O-). Also, R 1 and R 3 may have a similar structure.

[0067] In the above (1) and (2), the lower limit of the number of carbon atoms of R 2 may be 3 or more. Also, the upper limit of the number of carbon atoms of R 2 may be 10 or less, or may be 8 or less. Also, R 2 for example, one or more methylene (-CH2-) groups may be substituted with oxygen (-O-), or it may be an unsubstituted aliphatic hydrocarbon group.

[0068] The molecular weight of the above ester compound is preferably 250 to 3000, more preferably 250 to 1000, and even more preferably 250 to 500. When the molecular weight of the above ester compound is within the above range, the adhesion to the ceramic green sheet (dielectric layer) is further improved.

[0069] Furthermore, the content of the ester compound can be appropriately adjusted so that the glass transition temperature Tg of the dried product (for evaluation) falls within a specific range. For example, the content of the ester compound is 0.01% by mass or more and 1.0% by mass or less relative to the entire conductive paste. When the content of the ester compound is within the above range, the adhesion between the dried film and the ceramic green sheet (dielectric layer) can be improved. Also, from the viewpoint of further improving adhesion, the lower limit of the ester compound content may be 0.05% by mass or more, or 0.1% by mass or more, relative to the entire conductive paste. Also, the upper limit of the ester compound content may be 0.7% by mass or less, or 0.4% by mass or less.

[0070] The upper limit of the ester compound content is not particularly limited, but may be, for example, 2% by mass or less, 1.8% by mass or less, 1.5% by mass or less, or 1.0% by mass or less. If the ester compound content exceeds 1.0% by mass, although adhesion improves, thermal decomposition and gas generation may occur when the laminate of the dried film and ceramic green sheet is debindered during the compression treatment. The ester compound content can be appropriately adjusted within the above range depending on the usage environment and other factors.

[0071] Furthermore, the content of the ester compound can be appropriately set according to the type and content of the binder resin. For example, the content of the ester compound may be set according to the content of the butyral resin. For example, the content of the ester compound may be 10 parts by mass or more and 90 parts by mass or less of the ester compound per 100 parts by mass of the butyral resin, with 10 parts by mass being the most appropriate amount. That's all.The amount may be 60 parts by mass or less, or 10 parts by mass or more and 50 parts by mass or less.

[0072] (b) Compounds having an amide structure Compounds having an amide structure may include, for example, compounds having the structural part shown in formula (3) below (hereinafter also referred to as "amide compounds").

[0073] [ka]

[0074] In equation (3) above, R 11 R represents a saturated or unsaturated aliphatic hydrocarbon group having 8 to 25 carbon atoms, and the aliphatic hydrocarbon group may be linear or branched, and the aliphatic hydrocarbon group may have one or more methylene (-CH2-) atoms substituted with oxygen (-O-), 12 represents hydrogen, a saturated or unsaturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and the aliphatic hydrocarbon group may be linear or branched, and one or more methylene (-CH2-) atoms in the aliphatic hydrocarbon group may be substituted with oxygen (-O-). The amide compound may not contain an acidic group (e.g., a carboxyl group). If an acidic group is present, the softening effect of the dried film may decrease.

[0075] Furthermore, the amide compound preferably has the structure shown in the following structural formula (4) or structural formula (5). [ka] [ka]

[0076] In equations (4) and (5) above, R 11 , R 15Each independently represents a saturated or unsaturated aliphatic hydrocarbon group having 8 to 25 carbon atoms, and the aliphatic hydrocarbon group may be linear or branched, and the aliphatic hydrocarbon group may have one or more methylene (-CH2-) atoms substituted with oxygen (-O-), R 12 , R 13 , R 14 Each independently represents hydrogen, a saturated or unsaturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, the aliphatic hydrocarbon group may be linear or branched, and the aliphatic hydrocarbon group may have one or more methylene (-CH2-) atoms substituted with oxygen (-O-), R 16 R represents a saturated or unsaturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and the aliphatic hydrocarbon group may be linear or branched, and one or more methylene (-CH2-) atoms in the aliphatic hydrocarbon group may be substituted with oxygen (-O-). 11 ~R 16 The number of carbon atoms includes the number of carbon atoms in the methylene group (-CH2-) that have been replaced by oxygen (-O-).

[0077] In the above equations (3) to (5), R 11 and R 15 The lower limit of the number of carbon atoms can be 8 or more, 12 or more, or 15 or more, independently of each other. Also, R 11 and R 15 The number of carbon atoms may be the same.

[0078] Also, R 11 and R 15 R may have one or more methylene (-CH2-) groups substituted with oxygen (-O-), or it may be an unsubstituted aliphatic hydrocarbon group. 11 and R 15 They may have a similar structure.

[0079] In the above equations (3) to (5), R 12 , R 13 , R 14 The upper limit of the number of carbon atoms may be 5 or less, or 3 or less. Also, R 12 , R 13 , R 14This may be an unsubstituted aliphatic hydrocarbon group, for example, one or more methylene (-CH2-) groups may be substituted with oxygen (-O-), or it may be hydrogen.

[0080] In equation (5) above, R 16 The upper limit of the number of carbon atoms may be 5 or less, 3 or less, or 2 or less. Also, R 16 This may consist of one or more methylene (-CH2-) groups substituted with oxygen (-O-), or it may be an unsubstituted saturated hydrocarbon group.

[0081] The molecular weight of the above amide compound is preferably 250 to 3000, more preferably 250 to 1000, and even more preferably 250 to 500. When the molecular weight of the above amide compound is within the above range, the adhesion to the ceramic green sheet (dielectric layer) is further improved.

[0082] Furthermore, the content of the above amide compound can be appropriately adjusted so that the glass transition temperature Tg of the dried product falls within a specific range. The content of the above amide compound is preferably 0.01% by mass or more and 1.0% by mass or less relative to the entire conductive paste. When the content of the above amide compound is within the above range, the adhesion between the dried film and the ceramic green sheet (dielectric layer) is improved. Also, from the viewpoint of further improving adhesion, the content of the amide compound may be 0.05% by mass or more and 0.1% by mass or more relative to the entire conductive paste. Furthermore, the upper limit of the content of the amide compound may be 0.7% by mass or less and 0.4% by mass or less.

[0083] The upper limit of the amide compound content may be 2% by mass or less, 1.8% by mass or less, 1.5% by mass or less, 1.0% by mass or less, or less than 1.0% by mass. If the amide compound content exceeds 1.0% by mass, although adhesion improves, thermal decomposition and gas generation may occur when the laminate of the dried film and ceramic green sheet is debindered during the compression treatment. The amide compound content can be appropriately adjusted within the above range depending on the usage environment and other factors.

[0084] Furthermore, the content of the amide compound can be appropriately set according to the type and content of the binder resin. For example, the content of the amide compound may be set according to the content of the butyral resin. For example, the amide compound may be contained in 10 to 90 parts by mass per 100 parts by mass of butyral resin, or 10 parts by mass That's all. The amount may be 60 parts by mass or less, or 10 parts by mass or more and 50 parts by mass or less.

[0085] (c) Compounds having a phosphate group A compound containing a phosphate group (phosphate compound) is a compound that has a phosphate group at its terminal end. Phosphate compounds may, for example, have a polymer structure.

[0086] The phosphate compound may have a structure represented by the following structural formula (6-1), for example. [ka]

[0087] In formula (6-1) above, each R independently represents a structure containing hydrogen or one or more elements from the group consisting of alkyl chains, ether chains, and ester chains, and at least one of R represents a structure containing one or more elements from the group consisting of alkyl chains, ether chains, and ester chains. Furthermore, if R has an ether chain, the ether chain may have a single ether structure or may be a polyether chain having multiple ether structures. If R has an ester chain, the ester chain may have a single ester structure or may have multiple ester structures. In addition, the terminal phosphate group (acidic group) may be neutralized by amine.

[0088] The phosphate compound may have a structure represented by the following structural formula (6-2), for example. [ka]

[0089] In formula (6-2) above, R represents a structure comprising one or more elements from the group consisting of alkyl chains, polyether chains, and polyester chains. The phosphoric acid compound may, for example, have a polyether chain, or it may have both a polyether chain and a polyester chain. Furthermore, R may be a linear structure. In addition, the terminal phosphoric acid group (acidic group) may be neutralized by an amine.

[0090] The molecular weight of the above phosphoric acid compound is preferably 250 to 3000, more preferably 1000 to 3000, and even more preferably 1500 to 2500. When the molecular weight of the above phosphoric acid compound is within the above range, the adhesion to the ceramic green sheet (dielectric layer) is further improved.

[0091] Furthermore, the content of the above-mentioned phosphoric acid compound can be appropriately adjusted so that the glass transition temperature Tg of the dried product falls within a specific range. For example, the content of the above-mentioned phosphoric acid compound is 0.01% by mass or more and 1.0% by mass or less relative to the entire conductive paste. When the content of the above-mentioned phosphoric acid compound is within the above range, the adhesion between the dried film and the ceramic green sheet (dielectric layer) can be improved. Also, from the viewpoint of further improving adhesion, the content of the phosphoric acid compound may be 0.05% by mass or more, or 0.1% by mass or more, relative to the entire conductive paste. Furthermore, the upper limit of the content of the phosphoric acid compound may be 0.7% by mass or less.

[0092] The upper limit of the phosphoric acid compound content may be 2% by mass or less, 1.8% by mass or less, 1.5% by mass or less, 1.0% by mass or less, or less than 1.0% by mass. If the phosphoric acid compound content exceeds 1.0% by mass, thermal decomposition and gas generation may occur when the laminate of the dried film and ceramic green sheet is debindered. The phosphoric acid compound content can be adjusted as appropriate within the above range depending on the usage environment.

[0093] Furthermore, the content of the phosphate compound can be appropriately set according to the type and content of the binder resin. For example, the content of the phosphate compound may be set according to the content of the butyral resin. For example, the phosphate compound may be contained in 10 to 90 parts by mass per 100 parts by mass of butyral resin, or 10 parts by mass. That's all. The amount may be 60 parts by mass or less, or 10 parts by mass or more and 50 parts by mass or less.

[0094] (d) Compounds having a rosin skeleton The compound having a rosin skeleton preferably includes a rosin derivative having a hydroxyl group or an amine group (hereinafter also simply referred to as "rosin derivative").

[0095] Here, rosin derivatives refer to compounds derived from abietic acid, etc. Examples include abietic acid and its derivatives such as pimaric acid-type resin acids like dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, diabietic acid, neoabietic acid, and levopimalic acid, hydrogenated rosins obtained by hydrogenating these, and disproportionated rosins obtained by disproportionating these, which are compounds having a rosin skeleton. Furthermore, the rosin skeleton may include a structure in which two or more rosin molecules are bonded together, or it may include a rosin ester structure.

[0096] The rosin derivative is preferably a rosin derivative having hydroxyl groups, more preferably having one or two hydroxyl groups, and even more preferably having two hydroxyl groups. The hydroxyl value of the rosin derivative may be, for example, 10 mg KOH / g or more, 20 mg KOH / g or more, 50 mg KOH / g or more, and even more preferably 100 mg KOH / g or more. There is no particular upper limit to the hydroxyl value, but for example, it is 200 mg KOH / g or less. Furthermore, it is preferable that the rosin derivative does not have acidic groups such as carboxyl groups. The acid value of the rosin derivative may be, for example, 20.0 mg KOH / g or less, and 5.0 mg KOH / g or less.

[0097] The molecular weight of the above rosin derivative is preferably 250 to 3000, more preferably 250 to 2000, and even more preferably 250 to 1200. When the molecular weight of the above rosin derivative is within the above range, the adhesion to the ceramic green sheet (dielectric layer) is further improved.

[0098] Furthermore, the content of the above rosin derivative can be appropriately adjusted so that the glass transition temperature Tg of the dried product falls within a specific range. Rosin derivativeThe content of the rosin derivative is preferably 0.01% by mass or more and 1.0% by mass or less relative to the entire conductive paste. When the content of the rosin derivative is within the above range, the adhesion between the dried film and the ceramic green sheet (dielectric layer) is improved. Furthermore, from the viewpoint of further improving adhesion, the content of the rosin derivative may be 0.1% by mass or more relative to the entire conductive paste.

[0099] The upper limit of the rosin derivative content may be 2% by mass or less, 1.8% by mass or less, 1.5% by mass or less, 1.0% by mass or less, or less than 1.0% by mass. If the rosin derivative content exceeds 1% by mass, although high adhesion is achieved, thermal decomposition and gas generation may occur when the laminate of the dried film and ceramic green sheet is debindered during the debinder treatment. The rosin derivative content can be appropriately adjusted within the above range depending on the usage environment. Furthermore, the upper limit of the rosin derivative may be 0.7% by mass or less, or 0.4% by mass or less. In the conductive paste of this embodiment, high adhesion can be achieved even if the upper limit of the rosin derivative is within the above range.

[0100] Furthermore, the content of the rosin derivative can be appropriately set according to the type and content of the binder resin. For example, the content of the rosin derivative may be set according to the content of the butyral resin. For example, the rosin derivative may be contained in 10 to 90 parts by mass per 100 parts by mass of butyral resin, or 10 parts by mass. That's all. The amount may be 60 parts by mass or less, or 10 parts by mass or more and 50 parts by mass or less.

[0101] (b) Dispersant The conductive paste may contain a dispersant as an additive. When a dispersant is included, the dispersibility of the conductive powder and ceramic powder can be improved. Examples of dispersants include acidic dispersants, basic dispersants, nonionic dispersants, and amphoteric dispersants. It is preferable to include at least one of an acidic dispersant and a basic dispersant, and more preferably an acidic dispersant. These dispersants may be used individually or in combination of two or more.

[0102] The acidic dispersant may include carboxylic acid-based dispersants such as higher fatty acids, polycarboxylic acid-based dispersants, phosphoric acid-based dispersants, and acidic dispersants having acidic groups such as polymer surfactants, and it is preferable to include at least one of a polycarboxylic acid-based dispersant and a phosphoric acid-based dispersant. Furthermore, the polycarboxylic acid-based dispersant may be a comb-shaped carboxylic acid having a comb-like structure.

[0103] The higher fatty acids can be either unsaturated or saturated carboxylic acids, and are not particularly limited, but examples include those with 11 or more carbon atoms, such as stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, and linolenic acid. Among these, oleic acid or stearic acid is preferred.

[0104] Furthermore, the acidic dispersant may be, for example, oleoylsarcosine, a compound of glycine and oleic acid, or an alkyl monoamine salt type amide compound using a higher fatty acid such as stearic acid or lauric acid instead of oleic acid.

[0105] Furthermore, a dicarboxylic acid may be included to further improve the effect of suppressing the separation between the conductive powder and the ceramic powder. A dicarboxylic acid is a carboxylic acid having two carboxyl groups (COO- groups). The average molecular weight of the dicarboxylic acid is not particularly limited, but may be, for example, 200 to 1000.

[0106] Examples of basic dispersants include aliphatic amines such as laurylamine, rosinamine, cetylamine, myristylamine, and stearylamine. The conductive paste is composed of the above-mentioned acidic dispersant and basic dispersant. Agent When it contains [the specified ingredient], it may exhibit superior dispersibility and viscosity stability over time.

[0107] The dispersant is contained in the conductive paste in an amount of, for example, 0.01% to 3% by mass relative to the total conductive paste. The upper limit of the dispersant content may be 2% by mass or less, 1% by mass or less, or 0.5% by mass or less. When the dispersant content is within the above range, the dispersibility of the conductive paste can be improved, and sheet attack and peeling defects of the green sheet can be suppressed.

[0108] (c) Other additives The conductive paste of this embodiment may contain other additives besides the components described above, if necessary. Other additives that can be used include, for example, conventionally known additives such as defoamers, plasticizers, surfactants, and thickeners.

[0109] (Conductive paste) The method for manufacturing the conductive paste according to this embodiment is not particularly limited, and conventionally known methods can be used. The conductive paste can be manufactured, for example, by stirring and kneading each of the above components using a three-roll mill, ball mill, mixer, etc.

[0110] Conductive paste can be suitably used in electronic components such as multilayer ceramic capacitors. A multilayer ceramic capacitor has a dielectric layer formed using a dielectric green sheet and an internal electrode layer formed using the conductive paste.

[0111] [Multilayer ceramic capacitors] Hereinafter, embodiments of the multilayer ceramic capacitor of the present invention will be described with reference to the drawings. In the drawings, schematic representations and changes in scale may be made as appropriate. Furthermore, the position and orientation of components will be described with reference to the XYZ Cartesian coordinate system shown in Figure 1 and other figures as appropriate. In this XYZ Cartesian coordinate system, the X and Y directions are horizontal directions, and the Z direction is vertical (up and down direction).

[0112] Figures 1A and 1B show a multilayer ceramic capacitor 1. The multilayer ceramic capacitor 1 comprises a ceramic laminate 10 in which dielectric layers 12 and internal electrode layers 11 are alternately stacked, and an external electrode 20.

[0113] The following describes a method for manufacturing a multilayer ceramic capacitor using the conductive paste described above. First, a conductive paste is printed onto a ceramic green sheet and dried to form a dried film. Multiple ceramic green sheets, each having this dried film on its upper surface, are laminated by pressing to obtain a laminate. The laminate is then fired to integrate it, thereby creating a ceramic laminate 10 in which internal electrode layers 11 and dielectric layers 12 are alternately laminated. Subsequently, a pair of external electrodes 20 are formed at both ends of the ceramic laminate 10 to manufacture a multilayer ceramic capacitor 1. A more detailed explanation follows below.

[0114] First, an unfired ceramic sheet, known as a green sheet, is prepared. This green sheet can be obtained by, for example, adding a binder resin such as polyvinyl butyral and a solvent such as terpineol to a predetermined ceramic raw material powder, then applying a dielectric layer paste to a support film such as a PET film in a sheet-like manner, drying it, and removing the solvent. The thickness of the dielectric layer made from the green sheet is not particularly limited, but from the viewpoint of miniaturizing multilayer ceramic capacitors, a thickness of 0.05 μm to 3 μm is preferred.

[0115] Next, the conductive paste described above is printed and applied to one side of a green sheet, and then dried to form a dried film on one side of the green sheet. Multiple such sheets are prepared. The thickness of the dried film formed from the conductive paste is preferably 1 μm or less after drying, from the viewpoint of thinning the internal electrode layer 11.

[0116] Next, the green sheets are peeled off the support film, and the green sheets and the dried film formed on one side of them are laminated alternately. Then, a laminate is obtained by heating and pressurizing. Alternatively, protective ceramic green sheets without conductive paste can be placed on both sides of the laminate.

[0117] Next, the laminate is cut to a predetermined size to form green chips, and then the green chips are subjected to a debinder treatment and fired in a reducing atmosphere to produce a laminated ceramic fired body (ceramic laminate 10). The atmosphere used for the debinder treatment is preferably air or an N2 gas atmosphere. The temperature used for the debinder treatment is, for example, 200°C to 400°C. Furthermore, the holding time at the above temperature during the debinder treatment is preferably 0.5 hours to 24 hours. The firing is performed in a reducing atmosphere to suppress oxidation of the metal used in the internal electrode layer, and the firing temperature of the laminate is, for example, 1000°C to 1350°C, with a holding time at the temperature of 0.5 hours to 8 hours.

[0118] By firing the green chips, the organic binder in the ceramic green sheet is completely removed, and the ceramic raw material powder is fired to form a ceramic dielectric layer 12. In addition, the organic vehicle in the dried film is removed, and nickel powder or nickel-based alloy powder is sintered or melted and integrated to form an internal electrode layer 11, and a multilayer ceramic fired body is formed in which multiple dielectric layers 12 and internal electrode layers 11 are alternately stacked. Furthermore, from the viewpoint of incorporating oxygen into the dielectric layer to improve reliability and suppressing re-oxidation of the internal electrode, the multilayer ceramic fired body may be subjected to annealing treatment after firing.

[0119] Then, a multilayer ceramic capacitor 1 is manufactured by providing a pair of external electrodes 20 to the fabricated multilayer ceramic firing body. For example, the external electrodes 20 comprise an external electrode layer 21 and a plating layer 22. The external electrode layer 21 is electrically connected to the internal electrode layer 11. Suitable materials for the external electrodes 20 include, for example, copper, nickel, or alloys thereof. Electronic components other than multilayer ceramic capacitors can also be used. [Examples]

[0120] The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited in any way by the examples.

[0121] [Evaluation Method] (Evaluation of adhesion) A conductive paste (sample) was applied to the surface of a pre-prepared green sheet containing barium titanate and polyvinyl butyral to form a conductive paste film with a wet thickness of 35 μm. The resulting green sheet and the conductive paste film formed on its surface for internal electrodes were dried at 75°C for 20 minutes to form a dried film on the green sheet. The dried sheet (dried film-green sheet) and another green sheet were stacked with the conductive paste-coated side sandwiched between the green sheets, and then pressed at 40°C and 20 MPa for 20 seconds to create a laminate (for evaluation).

[0122] The obtained laminate was cut into 1 cm squares, and both sides of the laminate were set in jigs on a tensile testing machine (Shimadzu Corporation, AGS-50NX) using tape, and then a tensile test was performed. The test speed was 20 mm / min, and the breaking force (the force required to peel the dry film from the green sheet) was recorded. The breaking force of Comparative Example 1 was set to 100%, and the breaking force of each sample was evaluated as a percentage.

[0123] (hardness measurement) The surface (dry film side) of a green sheet, formed with a conductive paste film (dry film) prepared under the same conditions as for adhesion evaluation, was measured at n=5 points using a micro-Vickers hardness tester (Shimadzu Corporation, HMV-G21DT) under a test force of 98 mN, and the average value was calculated. Hardness measurements were performed by attaching the sample to a glass substrate, placing it on the heating stage of the hardness tester, and measuring at room temperature (25°C) without heating, and at 60°C. When measuring Vickers hardness (60°C), the dry film to be measured was first allowed to stand at 60°C for 3 minutes to adjust its condition, and then measured while heated at 60°C.

[0124] (Measurement of glass transition temperature Tg) The components of the conductive paste, excluding the conductive powder and ceramic powder, namely ethyl cellulose resin, polyvinyl butyral resin, additives, and organic solvents, were weighed to the same amount as those contained in the conductive paste. These were then mixed at 2000 rpm for 4 minutes using a self-rotating mixer (Sinky, ARE-310). The resulting liquid (mixture) was then applied to a PET film using an applicator to a wet film thickness of 254 μm and dried at 120°C for 40 minutes to obtain a sample for evaluation. Note that the organic solvent in the mixture was removed during drying.

[0125] Using a differential scanning calorimeter (NETC Japan Co., Ltd., DSC3100), 10 mg of a dried evaluation sample was placed in an aluminum pan and heated from 0°C to 140°C at a heating rate of 10°C / min under a nitrogen stream of 100 mL / min. The glass transition point Tg in the low-temperature region was determined from the peak of the endothermic curve obtained.

[0126] (pyrolysis temperature measurement) The thermal decomposition temperature of the additives used in the conductive paste was measured using a thermal decomposition gravimetric analyzer (NETC STA25000REGULUS). The measurement temperature was under nitrogen, and the temperature was increased from 20°C to 550°C at a heating rate of 5°C / min. The temperature at which the differential heating loss was greatest, i.e., the temperature at which the weight loss rate in thermogravimetric analysis was maximum, was defined as the thermal decomposition temperature (maximum thermal decomposition temperature).

[0127] [Materials used] (conductive powder) Ni powder (SEM average particle size 0.2 μm) was used as the conductive powder.

[0128] (Ceramic powder) Barium titanate (BaTiO3; SEM average particle size 0.10 μm) was used as the ceramic powder.

[0129] (Binder resin) Polyvinyl butyral resin (PVB) and ethyl cellulose resin (EC) were used as binder resins.

[0130] (Dispersant) In both the examples and comparative examples, a polycarboxylic acid-based dispersant, which is an acid-based dispersant, was used as a common dispersant (additive).

[0131] (Additives) The following compounds were used as additives (including comparative examples) to adjust the glass transition temperature (Tg).

[0132] (1) Phosphate compound A (a copolymer having a phosphate group and an ester structure, molecular weight: 1600) (2) Phosphate compound B (a copolymer having an amine-neutralized phosphate group and an ester structure, molecular weight: 2000) (3) Phosphate compound C: Copolymer of phosphate ester salt (alkylammonium salt) (4) Ester compounds: Having the structure of formula (a) below (R 1 =CH3(CH2)3OC2H4-, R 2 =-(CH2)4-, R 3 =-C2H4O(CH2)3CH3) (5) Amide compounds: Having the structure of formula (b) below (6) Rosin derivatives: Having the structure of formula (c) below (R=-CH2NH2) (7) Polycarboxylic acids (having polyoxyalkylene as a graft chain) (8) Dicarboxylic acid (2-(octadecen-1-yl)succinic acid)

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] (Organic solvents) Dihydroterpineol (DHT) and mineral spirits (MSA) were used as organic solvents.

[0137] [Example 1] A conductive paste was prepared by adding 49% by mass of conductive powder, 12% by mass of ceramic powder, 0.15% by mass of an acid-based dispersant, 0.3% by mass of phosphoric acid compound A (additive), 2.5% by mass of binder resin (PVB:EC = 7:3 (mass ratio)), and the remainder being an organic solvent (DHT:MSA = 60:40 (mass ratio)), to a total of 100% by mass. These materials were then mixed to produce a conductive paste. The content of each material in the conductive paste and the evaluation results are shown in Table 1.

[0138] [Examples 2-11, Comparative Examples 1-4] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that the type and content of additives were changed as shown in Table 1. The content of each material in the conductive paste and the evaluation results are shown in Table 1.

[0139] [Table 1]

[0140] (Evaluation results) Compared to the conductive pastes of Comparative Examples 1 to 4, the conductive pastes of Examples 1 to 11 had a glass transition temperature (Tg) of 55°C or lower in the low-temperature range and exhibited improved adhesion. [Industrial applicability]

[0141] When the conductive paste of the present invention is used to form the internal electrodes of a multilayer ceramic capacitor, highly reliable multilayer ceramic capacitors can be obtained with high productivity. Therefore, the conductive paste of the present invention can be suitably used for internal electrodes of multilayer ceramic capacitors, which are chip components in electronic devices such as mobile phones and digital devices, where miniaturization is progressing.

[0142] Furthermore, the technical scope of the present invention is not limited to the embodiments described above. One or more of the requirements described above may be omitted. Also, the requirements described above may be combined as appropriate. In addition, to the extent permitted by law, all disclosures of the documents cited above in the embodiments will be incorporated into this text. In addition, to the extent permitted by law, the contents of Japanese Patent Application No. 2022-052668 will be incorporated into this text.

[0143] Embodiments of the present invention may include the following configurations.

[0144] [1] A conductive paste comprising conductive powder, binder resin, additives, and an organic solvent, The glass transition temperature of the dried product obtained by mixing the binder resin, the additive, and the organic solvent in the same proportions as the conductive paste, is 30°C or higher and 55°C or lower. Conductive paste.

[0145] [2] The conductive paste according to [1], wherein the additive comprises a compound that can lower the glass transition temperature of the dried body, and the compound is present in an amount of 0.01% by mass or more and 2.0% by mass or less relative to the entire conductive paste.

[0146] [3] The conductive paste according to [1] or [2], wherein the compound has a temperature of 200°C or higher at which the weight loss rate in thermogravimetric analysis is maximum.

[0147] [4] A conductive paste according to any one of [1] to [3], wherein the molecular weight of the compound is 250 or more and 3000 or less.

[0148] [5] The conductive paste according to any one of [1] to [4], further comprising an acidic dispersant and / or a basic dispersant as an additive.

[0149] [6] The conductive paste according to any one of [1] to [5], wherein the conductive powder comprises at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu and alloys thereof.

[0150] [7] The conductive paste according to any one of [1] to [6], wherein the conductive powder has an average particle size of 0.05 μm or more and 1.0 μm or less.

[0151] [8] The conductive paste according to any one of [1] to [7], wherein the binder resin contains a butyral resin.

[0152] [9] A conductive paste according to any one of [1] to [8], further comprising ceramic powder.

[0153]

[10] The conductive paste according to [9], wherein the ceramic powder contains barium titanate.

[0154]

[11] The conductive paste according to [9] or

[10] , wherein the ceramic powder has an average particle size of 0.01 μm or more and 0.5 μm or less.

[0155]

[12] The conductive paste according to any one of [9] to

[11] , wherein the ceramic powder is contained in an amount of 1% by mass or more and 20% by mass or less relative to the entire conductive paste.

[0156]

[13] A conductive paste described in any one of [1] to

[12] for use as an internal electrode in a multilayer ceramic component.

[0157] An electronic component formed using a conductive paste described in any one of [1] to

[13] .

[0158]

[15] Having at least a laminate in which a dielectric layer and an internal electrode layer are stacked, The internal electrode layer is a multilayer ceramic capacitor formed using the conductive paste described in

[13] . [Explanation of Symbols]

[0159] 1. Multilayer ceramic capacitor 10 Ceramic Laminate 11 Internal electrode layer 12 Dielectric layer 20 External electrode 21 External electrode layer 22 Plating layer

Claims

1. A conductive paste used by being applied to a ceramic green sheet, It comprises conductive powder, binder resin, additives, and organic solvents. The glass transition temperature of the dried product obtained by mixing the binder resin, the additive, and the organic solvent in the same proportions as the conductive paste, is 30°C or higher and 55°C or lower. Conductive paste.

2. The conductive paste according to claim 1, wherein the additive comprises a compound that can lower the glass transition temperature of the dried body, and the compound is present in an amount of 0.01% by mass or more and 2.0% by mass or less of the total conductive paste.

3. The additive comprises a compound that can lower the glass transition temperature of the dried product. The conductive paste according to claim 1, wherein the compound has a temperature of 200°C or higher at which the weight loss rate in thermogravimetric analysis is maximized.

4. The additive comprises a compound that can lower the glass transition temperature of the dried product. The conductive paste according to claim 1, wherein the molecular weight of the compound is 250 or more and 3000 or less.

5. The conductive paste according to claim 1, wherein the additive further comprises an acidic dispersant and / or a basic dispersant.

6. The conductive paste according to claim 1, wherein the conductive powder comprises at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu, and alloys thereof.

7. The conductive paste according to claim 1, wherein the conductive powder has an average particle size of 0.05 μm or more and 1.0 μm or less.

8. The conductive paste according to claim 1, wherein the binder resin includes a butyral-based resin.

9. Furthermore, the conductive paste according to claim 1, further comprising ceramic powder.

10. The conductive paste according to claim 9, wherein the ceramic powder contains barium titanate.

11. The conductive paste according to claim 9, wherein the ceramic powder has an average particle size of 0.01 μm or more and 0.5 μm or less.

12. The conductive paste according to claim 9, wherein the ceramic powder is contained in an amount of 1% by mass or more and 20% by mass or less relative to the entire conductive paste.

13. The conductive paste according to claim 1, for use as an internal electrode in a multilayer ceramic component.

14. An electronic component formed using the conductive paste described in any one of claims 1 to 13.

15. The laminate comprises at least a dielectric layer and an internal electrode layer, The internal electrode layer is formed using the conductive paste described in claim 13, in a multilayer ceramic capacitor.

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