Slurry composition, dielectric layer, electrode layer, and multilayer ceramic capacitor

Abstract

Providing a slurry composition excellent in dispersion stability and drying rate. 【Solution means】The present invention is a slurry composition containing a dielectric material, a polymer, and a solvent, wherein the solvent is represented by the following formula (A): R 1 =O (A) [In formula (A), R 1 is a divalent alicyclic hydrocarbon group.] a ketone solvent A represented by, and the following formula (B): R 2 -O-R 3 (B) [In formula (B), R 2 is a monovalent alicyclic hydrocarbon group, and R 3 is a monovalent hydrocarbon group.] It is a slurry composition containing at least one of an ether solvent B represented by, and the total ratio of the ketone solvent A and the ether solvent B in the whole solvent is 50% by mass or more.

Description

[Technical Field]

[0001] The present invention relates to a slurry composition, a dielectric layer, an electrode layer, and a multilayer ceramic capacitor. [Background technology]

[0002] Electronic components used in various electronic devices are becoming smaller and more layered, and multilayer electronic components such as multilayer circuit boards, multilayer coils, and multilayer ceramic capacitors are widely used.

[0003] In particular, multilayer ceramic capacitors can be manufactured as follows, for example. First, a slurry composition for a dielectric layer is prepared, containing a binder, powdered dielectric material, and a solvent. This slurry composition is then applied to a release substrate or the like to form a dielectric layer (a so-called ceramic green sheet). Next, a slurry composition for an electrode layer, containing a binder, powdered conductive material, a solvent, and optionally powdered dielectric material, is applied to the dielectric layer to form an internal electrode layer and obtain a laminate. Then, the obtained laminates are stacked so that the internal electrode layers and dielectric layers alternately overlap, and a degreasing treatment (binder removal treatment) is optionally performed. Finally, the laminate is sintered to obtain a sintered product. Finally, an external electrode is formed on the end face of the obtained sintered product to obtain a multilayer ceramic capacitor.

[0004] In recent years, in order to impart superior characteristics to multilayer ceramic capacitors, progress has been made in developing slurry compositions used in the manufacture of multilayer ceramic capacitors.

[0005] For example, Patent Document 1 proposes a slurry composition that can produce ceramic green sheets for use in the manufacture of multilayer ceramic capacitors, which have less binder residue after de-bindering and excellent smoothness and density of ceramic particles after de-bindering. This slurry composition includes a dispersion medium consisting of toluene and ethanol, ceramic powder having a predetermined average particle size, and a binder consisting of a predetermined (meth)acrylate copolymer.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Here, the slurry composition can be stored for a certain period (for example, 7 days) after being prepared. From the viewpoint of uniformly applying the slurry composition and suppressing variations in the performance of laminated ceramic capacitors and the like, it is desirable that the viscosity change of the slurry composition is small when comparing the viscosity after storage for a certain period with the viscosity immediately after preparation, and that the dispersion stability is excellent.

[0008] Further, since the water content of the coating film obtained using the slurry composition can be effectively reduced, and as a result, the performance of laminated ceramic capacitors and the like can be improved, it is desirable that the slurry composition has an excellent drying rate.

[0009] Therefore, an object of the present invention is to provide a slurry composition excellent in dispersion stability and drying rate. Another object of the present invention is to provide a dielectric layer including a coating film using the above slurry composition. Another object of the present invention is to provide an electrode layer including a coating film using the above slurry composition. Another object of the present invention is to provide a laminated ceramic capacitor using the above dielectric layer or electrode layer.

Means for Solving the Problems

[0010] The present inventor diligently studied for the purpose of solving the above problems. And the present inventor newly found that the above problems can be solved with a slurry composition containing a dielectric material, a polymer, and a predetermined solvent, and completed the present invention.

[0011] That is, the object of the present invention is to advantageously solve the above problems. [1] The present invention relates to a slurry composition containing a dielectric material, a polymer, and a solvent, wherein the solvent is represented by the following formula (A): R 2 =O (A) [In formula (A), R 1 is a divalent alicyclic hydrocarbon group.] and a ketone solvent A represented by the following formula (B): R 2 -O-R 3 (B) [In formula (B), R 2 is a monovalent alicyclic hydrocarbon group, and R 3 is a monovalent hydrocarbon group.] and includes at least one of an ether solvent B represented by the following formula (B), and the total proportion of the ketone solvent A and the ether solvent B in the total solvent is 50% by mass or more. The slurry composition as described above is excellent in dispersion stability and drying rate.

[0012] [2] In the slurry composition of [1] above, it is preferable that the dielectric material has a perovskite structure. If the dielectric material has a perovskite structure, the performance of the laminated ceramic capacitor obtained when the slurry composition is used in the manufacture of the laminated ceramic capacitor can be improved.

[0013] [3] In the slurry composition of [1] or [2] above, it is preferable that the polymer contains a hydrophilic group-containing structural unit. If the polymer contains a hydrophilic group-containing structural unit, the dispersion stability of the slurry composition can be improved.

[0014] [4] In the slurry composition of any one of [1] to [3] above, the alicyclic hydrocarbon groups of the R<00000​​​​​​​If the alicyclic hydrocarbon group has a five-membered ring, the dispersion stability of the slurry composition can be improved.

[0015] [5] Any of the slurry compositions described in [1] to [4] above may further contain a conductive material. If the slurry composition further contains a conductive material, the slurry composition can be suitably used for preparing electrode layers.

[0016] Furthermore, the present invention aims to advantageously solve the above problems, and [6] the present invention is a dielectric layer comprising a coated film using any of the slurry compositions [1] to [4] above. With a dielectric layer like the one described above, multilayer ceramic capacitors can exhibit superior performance, and variations in their performance can be suppressed.

[0017] Furthermore, this invention aims to advantageously solve the above problems, and [7] the present invention is an electrode layer comprising a coating film using the slurry composition described in [5] above. With an electrode layer like the one described above, multilayer ceramic capacitors can exhibit superior performance, and variations in their performance can be suppressed.

[0018] Furthermore, the present invention aims to advantageously solve the above problems, [8] and the present invention is a multilayer ceramic capacitor comprising a dielectric, an internal electrode, and an external electrode, wherein the dielectric is made of the dielectric layer described in [6] above, or at least one of the internal electrode and the external electrode is made of the electrode layer described in [7] above. The multilayer ceramic capacitors described above offer excellent performance and suppress performance variations. [Effects of the Invention]

[0019] According to the present invention, a slurry composition with excellent dispersion stability and drying speed can be provided. Furthermore, according to the present invention, a dielectric layer comprising a coated film using the above-mentioned slurry composition can be provided. Furthermore, according to the present invention, an electrode layer comprising a coated film using the above-mentioned slurry composition can be provided. Furthermore, according to the present invention, a multilayer ceramic capacitor using the dielectric layer or the electrode layer described above can be provided. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic cross-sectional view showing an example of a multilayer ceramic capacitor of the present invention. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described below.

[0022] (Slurry composition) The slurry composition of the present invention comprises a dielectric material, a polymer, and a solvent. Furthermore, in the slurry composition of the present invention, the solvent is of the following formula (A): R 1 =O (A) [In formula (A), R 1 It is a divalent alicyclic hydrocarbon group. Ketone solvent A, represented by the following formula (B): R 2 -OR 3 (B) [In formula (B), R 2 R is a monovalent alicyclic hydrocarbon group, 3 It is a monovalent hydrocarbon group. It contains at least one of the ether solvent B represented by [formula]. Furthermore, in the slurry composition of the present invention, the total proportion of ketone solvent A and ether solvent B in the total solvent is 50% by mass or more. The slurry composition described above exhibits excellent dispersion stability and drying speed. Although the reason for this is not entirely clear, it is presumed that the presence of at least one of ketone solvent A and ether solvent B in the solvent in a predetermined proportion allows the polymer in the slurry to dissolve and / or disperse well in the solvent. Furthermore, dielectric layers and electrode layers that can be manufactured using a slurry composition may absorb moisture from the external atmosphere during storage, increasing the moisture content in the dielectric and electrode layers and potentially adversely affecting the performance of the multilayer ceramic capacitor. However, with the slurry composition described above, the hygroscopicity of the dielectric and electrode layers can be reduced. Furthermore, the slurry composition of the present invention may optionally contain components other than the dielectric material, polymer, and solvent described above (hereinafter sometimes referred to as "other components").

[0023] <Dielectric materials> The dielectric material is not particularly limited as long as it is a dielectric powder material, but it is preferable to use a ceramic material. Examples of ceramic materials that can be used include zirconia, aluminum silicate, titanium oxide, zinc oxide, barium titanate, calcium zirconate, calcium titanate, strontium titanate, magnesia, sialon, spinemulite, silicon carbide, silicon nitride, and aluminum nitride. These ceramic materials may be used individually or in combination of two or more.

[0024] Here, the dielectric material is preferably a perovskite structure because it can improve the performance of the resulting multilayer ceramic capacitor when the slurry composition is used in the manufacture of a multilayer ceramic capacitor. Furthermore, "perovskite structure" refers to a structure represented by the general formula ABO3, and "a dielectric material having a perovskite structure" means that at least a portion of the dielectric material contains the structure represented by the general formula ABO3.

[0025] As a dielectric material having a perovskite structure, ceramic materials with a perovskite structure as the main phase are preferred. Examples of such ceramic materials include barium titanate (BaTiO3), calcium zirconate (CaZrO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), and Ba that form a perovskite structure. 1-x-y Ca x Sry Ti 1-z Zr z Examples include O3 (0≦x≦1, 0≦y≦1, 0≦z≦1). Among these, barium titanate is preferred as a ceramic material with a perovskite structure as its main phase.

[0026] The volume-average particle diameter of the dielectric material is preferably 0.01 μm or more, more preferably 0.02 μm or more, even more preferably 0.05 μm or more, even more preferably 0.08 μm or more, preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.5 μm or less, even more preferably 0.3 μm or less, and even more preferably 0.2 μm or less. In this specification, the volume-average particle diameter of a dielectric material refers to the particle diameter at which the cumulative volume calculated from the smallest diameter side accounts for 50% of the particle diameter distribution (volume-based) obtained by laser diffraction.

[0027] <polymer> In the slurry composition of the present invention, the polymer is a component that can function as a binder in the dielectric layer, electrode layer, etc.

[0028] Here, the polymer is not particularly limited, but it is preferable that it contains a structural unit having a hydrophilic group (hereinafter sometimes referred to as "hydrophilic group-containing structural unit") in order to improve the dispersion stability of the slurry composition. Examples of hydrophilic groups include acid groups such as carboxyl groups, sulfonic acid groups, and phosphate groups; hydroxyl groups; amide groups; and so on. Among these, it is preferable that the hydrophilic group be at least one of an acid group and a hydroxyl group, and more preferably at least one of a carboxyl group and a hydroxyl group, in order to further improve the dispersion stability of the slurry composition.

[0029] The polymer may contain, in addition to hydrophilic group-containing structural units, alkyl (meth)acrylate monomer units, etc. Furthermore, the polymer may contain structural units other than hydrophilic group-containing structural units and alkyl (meth)acrylate monomer units (hereinafter sometimes referred to as "other structural units"). In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0030] <<Hydrophilic group-containing structural unit>> Even if the hydrophilic group-containing structural unit is a structural unit that can be formed by monomers having hydrophilic groups (hereinafter sometimes referred to as "hydrophilic group-containing monomers"), it may also be a structural unit obtained by first obtaining a polymer using a monomer composition containing monomers having a predetermined functional group, and then modifying or converting the functional group into a hydrophilic group.

[0031] Examples of carboxyl group-containing monomers that can form structural units having a carboxyl group as a hydrophilic group (hereinafter sometimes referred to as "carboxyl group-containing structural units") include monocarboxylic acids and their derivatives, as well as dicarboxylic acids and their acid anhydrides. Examples of monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Examples of monocarboxylic acid derivatives include 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, and β-diaminoacrylic acid. Examples of dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of dicarboxylic acid derivatives include methyl maleic acid, dimethyl maleic acid, phenyl maleic acid, chloro maleic acid, dichloro maleic acid, fluoromaleic acid, and maleic acid esters such as methyl allyl maleate, diphenyl maleate, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate. Examples of dicarboxylic acid acid anhydrides include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride. Furthermore, as carboxyl group-containing monomers, acid anhydrides that generate carboxyl groups through hydrolysis can also be used. Furthermore, the above-mentioned carboxyl group-containing monomers may be used individually or in combination of multiple types.

[0032] Examples of sulfonic acid group-containing monomers that can form structural units having a sulfonic acid group as a hydrophilic group (hereinafter sometimes referred to as "sulfonic acid group-containing structural units") include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth)allyl sulfonic acid, styrene sulfonic acid, ethyl (meth)acrylate-2-sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, and 3-alyloxy-2-hydroxypropanesulfonic acid. These may be used individually or in combination of multiple types. In this specification, "(meth)allyl" means allyl and / or methallyl.

[0033] Examples of phosphate-containing monomers that can form structural units having a phosphate group as a hydrophilic group (hereinafter sometimes referred to as "phosphate-containing structural units") include 2-(meth)acryloyloxyethyl phosphate, methyl-2-(meth)acryloyloxyethyl phosphate, ethyl-(meth)acryloyloxyethyl phosphate, vinylphosphonic acid, and dimethyl vinylphosphonate. These may be used individually or in combination. In this specification, "(meth)acryloyl" means acryloyl and / or methacryloyl.

[0034] Examples of amide group-containing monomers that can form structural units having an amide group as a hydrophilic group (hereinafter sometimes referred to as "amide group-containing structural units") include acrylamide and methacrylamide. These may be used individually or in combination of multiple types.

[0035] Structural units having a hydroxyl group as a hydrophilic group (hereinafter sometimes referred to as "hydroxyl group-containing structural units") are not particularly limited in structure as long as they are repeating units having a hydroxyl group. Methods for introducing hydroxyl group-containing structural units into polymers include, for example, the following methods (1) or (2): (1) A method for preparing a polymer containing a hydroxyl group-containing structural unit from a monomer composition containing a hydroxyl group-containing monomer. (2) A method for preparing a polymer from a monomer composition containing a vinyl carboxylate monomer represented by the general formula: R-CO-O-CH=CH2 (wherein R is any structure, but preferably an alkyl group having 1 to 19 carbon atoms), and saponifying the polymer to convert all or part of the "R-CO-O-" in the vinyl carboxylate monomer unit into a hydroxyl group, thereby preparing a polymer containing a vinyl alcohol unit and optionally containing a vinyl carboxylate monomer unit.

[0036] The hydroxyl group-containing monomers used in the method described in (1) above include ethylenically unsaturated alcohols such as (meth)allyl alcohol, 3-buten-1-ol, and 5-hexen-1-ol; alkanol esters of ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate (2-hydroxyethyl methacrylate), 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate, and di-2-hydroxypropyl itaconate; general formula: CH2=CR 1 -COO-(C q H 2q O) p -H(where p is an integer from 2 to 9, q is an integer from 2 to 4, R 1Polyalkylene glycols represented by (where represents hydrogen or a methyl group) and (meth)acrylic acid esters; mono(meth)acrylic acid esters of dihydroxy esters of dicarboxylic acids such as 2-hydroxyethyl-2'-(meth)acryloyloxyethyl phthalate and 2-hydroxyethyl-2'-(meth)acryloyloxyethyl succinate; vinyl ethers such as 2-hydroxyethyl vinyl ether and 2-hydroxypropyl vinyl ether; mono(meth)acrylic acid esters of alkylene glycols such as (meth)allyl-2-hydroxyethyl ether, (meth)allyl-2-hydroxypropyl ether, (meth)allyl-3-hydroxypropyl ether, (meth)allyl-2-hydroxybutyl ether, (meth)allyl-3-hydroxybutyl ether, (meth)allyl-4-hydroxybutyl ether, and (meth)allyl-6-hydroxyhexyl ether. Examples include lyl ethers; polyoxyalkylene glycol mono(meth)allyl ethers such as diethylene glycol mono(meth)allyl ether and dipropylene glycol mono(meth)allyl ether; mono(meth)allyl ethers of halogen and hydroxy-substituted (poly)alkylene glycols such as glycerin mono(meth)allyl ether, (meth)allyl-2-chloro-3-hydroxypropyl ether, and (meth)allyl-2-hydroxy-3-chloropropyl ether; mono(meth)allyl ethers of polyhydric phenols such as eugenol and isoeugenol and their halogen-substituted derivatives; (meth)allyl thioethers of alkylene glycols such as (meth)allyl-2-hydroxyethyl thioether and (meth)allyl-2-hydroxypropyl thioether; N-2-hydroxyethyl (meth)acrylamide, N-methylolacrylamide, etc. These can be used individually or in combination of two or more.

[0037] Examples of vinyl carboxylate monomers used in the method described in (2) above include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, and vinyl stearate. These can be used individually or in combination of two or more. Among these, vinyl acetate is preferred.

[0038] Here, when preparing a polymer by the method described in (2) above, some of the hydroxyl groups of the obtained polymer may be acetalized. Examples of such polymers include polyvinyl acetals such as polyvinyl butyral, in which some of the hydroxyl groups of the polymer are acetalized with butyraldehyde. For example, as a polyvinyl acetal, S-LEC BL-2H manufactured by Sekisui Chemical Co., Ltd. can be used.

[0039] The content of hydrophilic group-containing structural units in a polymer is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 15% by mass or more, and even more preferably 19% by mass or more, when the total repeating units (total monomer units and total structural units) contained in the polymer are taken as 100% by mass. If the content of hydrophilic group-containing structural units in the polymer is above the above lower limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the proportion of hydrophilic group-containing structural units in the polymer is, for example, 95% by mass or less, or 90% by mass or less, when the total repeating units (total monomer units and total structural units) contained in the polymer are taken as 100% by mass. The proportions of specific monomer units and structural units in a polymer are: 1 H-NMR and 13 It can be measured using nuclear magnetic resonance (NMR) methods such as 13C-NMR.

[0040] <<(meth)acrylate alkyl ester monomer unit>> The alkyl (meth)acrylate monomer units that a polymer may contain are monomer units that can be formed by alkyl (meth)acrylate monomers.

[0041] Examples of alkyl methacrylate monomers that can form alkyl methacrylate monomer units include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate, etc. Examples include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate. These may be used individually or in combination of two or more.

[0042] When the polymer contains alkyl (meth)acrylate monomer units, the content of alkyl (meth)acrylate monomer units in the polymer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more, preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 85% by mass or less, based on the total repeating units (total monomer units and total structural units) contained in the polymer being 100% by mass. In this specification, polymers containing 50% by mass or more of alkyl (meth)acrylate monomer units may be referred to as "acrylic polymers."

[0043] <<Other structural units>> Other structural units that may be optionally included in the polymer are not particularly limited. Examples of monomers that can form other structural units include crosslinkable monomers (monomers that can be crosslinked) such as polyfunctional ethylenically unsaturated carboxylic acid ester monomers having two or more ethylenically unsaturated bonds (C=C) in the molecule, such as allyl glycidyl ether, allyl (meth)acrylate, and ethoxylated pentaerythritol tetraacrylate; olefins such as ethylene and propylene; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether; vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone; heterocyclic vinyl compounds such as N-vinylpyrrolidone, vinylpyridine, and vinylimidazole; amino group-containing monomers such as aminoethyl vinyl ether and dimethylaminoethyl vinyl ether; and the like. These other monomers may be used individually or in combination of two or more types. Furthermore, when a hydroxyl group-containing structural unit is introduced into a polymer using the method described in (2) above, the polymer obtained after saponification may contain vinyl carboxylate monomer units as other structural units. Also, when some of the hydroxyl groups of the polymer obtained by the method described in (2) above are acetalized, the polymer may contain vinyl acetal structural units as other structural units.

[0044] The proportion of other structural units in a polymer is, for example, 90% by mass or less, 85% by mass or less, 81% by mass or less, or 1% by mass or more, 5% by mass or more, or 10% by mass or more, when the total repeating units (total monomer units and total structural units) contained in the polymer are taken as 100% by mass.

[0045] <<Polymer content>> The polymer content in the slurry composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, based on 100 parts by mass of dielectric material. If the polymer content is above the lower limit mentioned above, the dispersion stability of the slurry composition can be effectively improved. On the other hand, if the polymer content is below the above upper limit, the density of the dielectric layer and electrode layer can be effectively improved.

[0046] <<Method for preparing polymers>> Polymers can be obtained, for example, by polymerizing monomer compositions obtained by mixing each of the above-mentioned monomers with any polymerization solvent in a known manner, using any polymerization method, and subjecting them to treatments such as saponification as necessary. Here, the polymerization method for the polymer is not limited, and any of the following methods may be used, for example, solution polymerization methods such as aqueous solution polymerization, slurry polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc. Furthermore, addition polymerization such as ionic polymerization, radical polymerization, and living radical polymerization can be used as the polymerization reaction. The additives used in polymerization, such as polymerization initiators, polymerization accelerators, emulsifiers, dispersants, and chain transfer agents (molecular weight adjusters), can be those commonly used, and the amounts used can also be those commonly used.

[0047] <Solvent> The solvent comprises at least one of ketone solvent A and ether solvent B. Furthermore, the solvent may optionally include solvents other than ketone solvent A and ether solvent B (hereinafter sometimes referred to as "other solvents").

[0048] <<Ketone Solvent A>> Ketone solvent A is given by the following formula (A): R 1 =O (A) Having a structure represented by Here, in equation (A), R 1R is a divalent alicyclic hydrocarbon group. That is, ketone solvent A is R 1 It has a structure in which an oxygen atom is directly double-bonded to the carbon ring of the alicyclic hydrocarbon group. 1 The alicyclic hydrocarbon group is not particularly limited as long as it has a carbocyclic ring, and the hydrogen atoms of the carbocyclic ring may be substituted with alkyl groups, alkenyl groups, alkynyl groups, etc. Ketone solvent A is typically a liquid at 25°C and 1 atm.

[0049] R 1 The alicyclic hydrocarbon group preferably has a 5-membered ring. 1 If the alicyclic hydrocarbon group has a five-membered ring, the dispersion stability of the slurry composition can be improved.

[0050] R 1 The number of carbon atoms in the alicyclic hydrocarbon group is preferably 4 or more, more preferably 5 or more, preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. R 1 If the number of carbon atoms in the alicyclic hydrocarbon group is within the above range, the dispersion stability of the slurry composition can be effectively improved.

[0051] R 1 Examples of alicyclic hydrocarbons constituting the alicyclic hydrocarbon group include cycloalkanes and cycloalkenes. Among these, cycloalkanes are preferred. Examples of the cycloalkanes mentioned above include cyclobutane, cyclopentane, cyclohexane, and cycloheptane. Among these, cyclobutane and cyclopentane are preferred, and cyclopentane is more preferred, because they can improve the dispersion stability of the slurry composition. In other words, cycloalkanone is preferred as the ketone solvent A, cyclobutanone and cyclopentanone are more preferred, and cyclopentanone is even more preferred.

[0052] <<Ether Solvent B>> The ether solvent B is given by the following formula (B): R 2 -OR 3 (B) It has a structure represented by the following: Here, in equation (B), R 2 R is a monovalent alicyclic hydrocarbon group, 3 It is a monovalent hydrocarbon group. 2 The alicyclic hydrocarbon group is not particularly limited as long as it has a carbocyclic ring, and the hydrogen atoms of the carbocyclic ring may be substituted with alkyl groups, alkenyl groups, alkynyl groups, etc. Note that ether solvent B is usually a liquid at 25°C and 1 atm.

[0053] R 2 The alicyclic hydrocarbon group preferably has a 5-membered ring. 2 If the alicyclic hydrocarbon group has a five-membered ring, the dispersion stability of the slurry composition can be improved.

[0054] R 2 The number of carbon atoms in the alicyclic hydrocarbon group is preferably 4 or more, more preferably 5 or more, preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. R 2 If the number of carbon atoms in the alicyclic hydrocarbon group is within the above range, the dispersion stability of the slurry composition can be effectively improved.

[0055] R 2 Examples of alicyclic hydrocarbons constituting the alicyclic hydrocarbon group include cycloalkanes and cycloalkenes. Among these, cycloalkanes are preferred. Examples of the cycloalkanes mentioned above include cyclobutane, cyclopentane, cyclohexane, and cycloheptane. Among these, cyclopentane is preferred because it can improve the dispersion stability of the slurry composition. That is, R 2 The alicyclic hydrocarbon group is preferably a cycloalkyl group, and more preferably a cyclopentyl group.

[0056] R 3 The number of carbon atoms in the hydrocarbon group is not particularly limited, but is preferably 10 or less, more preferably 6 or less, and even more preferably 2 or less.

[0057] R 3 The hydrocarbon group is not particularly limited and includes, for example, a chain-like aliphatic hydrocarbon group, a cyclic aliphatic hydrocarbon group, and an aromatic hydrocarbon ring group, but a chain-like aliphatic hydrocarbon group is preferred. Examples of linear aliphatic hydrocarbon groups include linear alkyl groups and linear alkenyl groups. Examples of linear alkyl groups include methyl groups, ethyl groups, propyl groups such as n-propyl and isopropyl groups, and butyl groups such as n-butyl, sec-butyl, isobutyl, and tert-butyl groups. Examples of linear alkenyl groups include vinyl groups and allyl groups. Among these, linear alkyl groups are preferred, methyl groups and ethyl groups are more preferred, and methyl groups are even more preferred.

[0058] In one embodiment of the present invention, the ether solvent B is R 2 The alicyclic hydrocarbon group is a cyclopentyl group, 3 It is preferable that the hydrocarbon group is a methyl group, that is, cyclopentyl methyl ether.

[0059] <<Other Solvents>> Other solvents are not particularly limited, but examples include alcohol solvents, ketone solvents other than ketone solvent A, and ether solvents other than ether solvent B. These may be used individually or in combination of two or more. Furthermore, it is preferable to include an alcohol solvent as another solvent, as this can improve the drying rate of the slurry composition.

[0060] Examples of alcoholic solvents include methanol, ethanol, and propanol. Among these, ethanol is preferred because it has low toxicity, is easy to handle, and can further improve the drying rate of the slurry composition.

[0061] <<Solvent Composition>> In the slurry composition of the present invention, the total proportion of ketone solvent A and ether solvent B in the total solvent must be 50% by mass or more, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. If the total proportion of ketone solvent A and ether solvent B in the total solvent is above the above lower limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, in the slurry composition of the present invention, if the total proportion of ketone solvent A and ether solvent B in the total solvent is less than or equal to the above upper limit, the drying speed of the slurry composition can be effectively improved. Furthermore, if the total proportion of ketone solvent A and ether solvent B in the total solvent is 100% by mass, the solvent consists of at least one of ketone solvent A and ether solvent B.

[0062] In the slurry composition of the present invention, when the solvent contains ketone solvent A, the proportion of ketone solvent A to the total solvent is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. If the proportion of ketone solvent A in the total solvent is above the above lower limit, the dispersion stability of the slurry composition can be effectively improved. In addition, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, if the proportion of ketone solvent A in the total solvent is below the above upper limit, the drying rate of the slurry composition can be effectively improved. Furthermore, a proportion of ketone solvent A in the total solvent being 100% by mass means that the solvent consists solely of ketone solvent A.

[0063] In the slurry composition of the present invention, when the solvent contains ether solvent B, the proportion of ether solvent B in the total solvent is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. If the proportion of ether solvent B in the total solvent is above the above lower limit, the dispersion stability of the slurry composition can be effectively improved. In addition, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, if the proportion of ether solvent B in the total solvent is below the above upper limit, the drying rate of the slurry composition can be effectively improved. Furthermore, a proportion of ether solvent B in the total solvent being 100% by mass means that the solvent consists solely of ether solvent B.

[0064] In the slurry composition of the present invention, when the solvent includes an alcohol solvent as another solvent, the proportion of the alcohol solvent in the total solvent is preferably 5% by mass or more, more preferably 10% by mass or more, required to be 50% by mass or less, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. If the proportion of the alcohol solvent in the total solvent is above the lower limit mentioned above, the drying speed of the slurry composition can be effectively improved. On the other hand, if the proportion of the alcohol solvent in the total solvent is below the above upper limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced.

[0065] In the slurry composition of the present invention, when the solvent includes at least one of ketone solvent A and ether solvent B and an alcohol solvent, the total ratio of ketone solvent A and ether solvent B to the proportion of alcohol solvent (ketone solvent A and ether solvent B / alcohol solvent) must be 1 or more by mass, preferably 2 or more, more preferably 3 or more, preferably 100 or less, more preferably 10 or less, and even more preferably 5 or less. If the total ratio of ketone solvent A and ether solvent B to the alcohol solvent is equal to or greater than the lower limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, if the total ratio of ketone solvent A and ether solvent B to the alcohol solvent is less than or equal to the above upper limit, the drying rate of the slurry composition can be effectively improved.

[0066] In the slurry composition of the present invention, when the solvent contains ketone solvent A and alcohol solvent, the ratio of ketone solvent A to the alcohol solvent (ketone solvent A / alcohol solvent) is preferably 1 or more by mass, more preferably 2 or more, even more preferably 3 or more, preferably 100 or less, more preferably 10 or less, and even more preferably 5 or less. If the ratio of ketone solvent A to the alcohol solvent is above the lower limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, if the ratio of ketone solvent A to the alcohol solvent is below the above upper limit, the drying speed of the slurry composition can be effectively improved.

[0067] In the slurry composition of the present invention, when the solvent contains ether solvent B and alcohol solvent, the ratio of ether solvent B to the alcohol solvent (ether solvent B / alcohol solvent) is preferably 1 or more by mass, more preferably 2 or more, even more preferably 3 or more, preferably 100 or less, more preferably 10 or less, and even more preferably 5 or less. If the ratio of ether solvent B to the alcohol solvent is above the lower limit, the dispersion stability of the slurry composition can be effectively improved. Furthermore, the hygroscopicity of the dielectric layer and electrode layer can be effectively reduced. On the other hand, if the ratio of ether solvent B to the alcohol solvent is below the above upper limit, the drying rate of the slurry composition can be effectively improved.

[0068] <Other ingredients> The slurry composition of the present invention may contain other components. Examples of other components include the above-mentioned additives used when polymerizing the polymer; plasticizers, etc.

[0069] The slurry composition of the present invention preferably contains a plasticizer as another component. While conventionally known plasticizers can be used, phthalate-based plasticizers are preferred from the viewpoint of dispersibility in the solvent. Examples of phthalate-based plasticizers include dioctyl phthalate, diisononyl phthalate, dibutyl phthalate, and bis(2-ethylhexyl) phthalate. These may be used individually or in combination of two or more. Among these, bis(2-ethylhexyl) phthalate is preferred.

[0070] The amount of plasticizer per 100 parts by mass of polymer is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, preferably 50 parts by mass or less, and more preferably 45 parts by mass or less. If the plasticizer content per 100 parts by mass of polymer is above the above lower limit, the dispersion stability of the slurry composition can be effectively improved. On the other hand, if the plasticizer content per 100 parts by mass of polymer is below the above upper limit, when a dielectric layer is formed using the slurry composition of the present invention, the wettability between the dielectric layer and the conductive paste for the internal electrodes can be effectively improved. Furthermore, when a release substrate with a dielectric layer, obtained by forming a dielectric layer on a release substrate described later, is wound around it, adhesion between the dielectric layer and the back surface of the release substrate, so-called blocking, can be effectively suppressed.

[0071] The amount of plasticizer per 100 parts by mass of dielectric material is, for example, 0.8 parts by mass or more, may be 1.2 parts by mass or more, may be, for example, 4 parts by mass or less, or may be 3.6 parts by mass or less.

[0072] <Solid content concentration of slurry composition> The solid content concentration of the slurry composition is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 40% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less.

[0073] <Applications of slurry compositions> The slurry composition of the present invention is not particularly limited, but it can be suitably used in the manufacture of multilayer ceramic capacitors because it can enable multilayer ceramic capacitors to exhibit excellent performance and suppress variations in the performance of multilayer ceramic capacitors. Specifically, the slurry composition of the present invention can be suitably used for forming dielectric layers used in the manufacture of multilayer ceramic capacitors, or for forming electrode layers (internal electrode layers, external electrode layers) used in the manufacture of multilayer ceramic capacitors.

[0074] <<Slurry composition for dielectric layers>> The slurry composition used for forming the dielectric layer (hereinafter sometimes referred to as the "dielectric layer slurry composition") typically does not contain the conductive material described later.

[0075] Here, when we say that a dielectric layer slurry composition does not contain conductive material, it means that the proportion of conductive material in the total solid content of the dielectric layer slurry composition is 1% by mass or less. Preferably, the proportion of conductive material in the total solid content of the dielectric layer slurry composition is 0.1% by mass or less, more preferably 0.01% by mass or less, and even more preferably 0% by mass.

[0076] <<Slurry composition for electrode layer>> The slurry composition used for forming the electrode layer (hereinafter sometimes referred to as the "electrode layer slurry composition") contains the conductive material described later.

[0077] Here, the conductive material is not particularly limited as long as it is a conductive powder material, and for example, one or more powders selected from Ni, Pd, Pt, Au, Ag, Cu, and their alloys can be used. Among these, Ni or Ni alloy 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 usually 50% by mass or more, and preferably 80% by mass or more. In addition, the Ni powder may contain several hundred ppm of S (sulfur) to suppress rapid gas generation due to partial thermal decomposition of the binder during the debinder treatment.

[0078] The average particle size of the conductive material is preferably 0.05 μm or more, more preferably 0.1 μm or more, preferably 1.0 μm or less, and more preferably 0.5 μm or less. In this specification, unless otherwise specified, the average particle size of conductive materials is the particle size calculated from the specific surface area obtained by the BET method. For example, the average particle size of Ni powder can be calculated by the following formula (1). Average particle diameter=6 / SA×ρ...(1) (ρ = 8.9 (true density of Ni), SA = BET specific surface area of ​​Ni powder)

[0079] The content of conductive material in the electrode layer slurry composition is preferably 100 parts by mass or more, more preferably 300 parts by mass or more, preferably 1000 parts by mass or less, and more preferably 700 parts by mass or less, when the dielectric material is 100 parts by mass.

[0080] <Method for preparing slurry composition> The slurry composition described above can be prepared by mixing the above-mentioned components by known methods. Specifically, the slurry composition can be prepared by mixing the above-mentioned components using a mixer such as a ball mill, sand mill, bead mill, pigment disperser, lye crusher, ultrasonic disperser, homogenizer, planetary mixer, film mixer, or orbital mixer.

[0081] (Dielectric layer) The dielectric layer of the present invention comprises a coated film using the slurry composition of the present invention described above. The slurry composition of the present invention used for the coated film of the dielectric layer is typically a slurry composition for dielectric layers. Here, the coating film (hereinafter sometimes referred to as "dielectric film") provided by the dielectric layer of the present invention uses the slurry composition of the present invention, which has excellent dispersion stability and drying speed, and therefore has excellent uniformity of film thickness, and the amount of water in the coating film is effectively reduced. Furthermore, since the dielectric layer of the present invention comprises a dielectric film using the slurry composition of the present invention, its hygroscopicity is reduced.

[0082] The dielectric film is not particularly limited, but may, for example, be a dried film obtained by partially or completely removing the solvent from the dielectric film. That is, the dielectric film comprises a dielectric material and a polymer, and may optionally contain a solvent and other components. Furthermore, since the dielectric film is a coated film using a slurry composition for dielectric layers, it typically does not contain conductive materials.

[0083] Each component contained in the dielectric film is the same as that contained in the slurry composition described above, and the preferred ratio of each component is the same as the preferred ratio of each component in the slurry composition.

[0084] The thickness of the dielectric film is preferably 0.1 μm or more, more preferably 0.5 μm or more, preferably 10 μm or less, and more preferably 5 μm or less.

[0085] The method for producing the dielectric film is not particularly limited; for example, it can be produced by applying the dielectric slurry composition of the present invention onto a release substrate and drying the resulting film as desired.

[0086] Here, the release substrate used when fabricating the dielectric film is not particularly limited, and examples include substrates containing resins such as polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, and polyvinyl chloride.

[0087] The release substrate preferably has a surface treatment applied to the side on which the dielectric film is formed to improve its release properties. The surface treatment is not particularly limited and includes, for example, surface treatment using a release agent such as a silicone-based release agent, a fluorine-based release agent, or a wax-based release agent.

[0088] The thickness of the release agent is not particularly limited, but it is usually between 20 μm and 100 μm.

[0089] The method for applying the dielectric slurry composition onto a release substrate is not particularly limited, and known application methods include, for example, the use of an applicator or various roll coaters such as gravure coaters and comma coaters (registered trademarks).

[0090] The method for drying the dielectric film formed on the release substrate is not particularly limited, and known drying methods using a hot air dryer can be cited as examples. The drying conditions can be appropriately set according to the solvent content in the dielectric film, the thickness of the dielectric film, etc., but the drying temperature is usually between 80°C and 150°C, and the drying time is usually between 3 minutes and 60 minutes.

[0091] The dielectric layer of the present invention may have a coating film formed on the dielectric film that can form internal electrodes of a multilayer ceramic capacitor. That is, the dielectric layer of the present invention may be in the form of a dielectric layer with a coating film for forming internal electrodes. Various printing methods such as screen printing, gravure printing, stamp printing, inkjet printing, and offset printing using patterns formed thereby; vacuum deposition for forming metal deposition films; and the like can be applied to form the coating film for forming internal electrodes. Here, when forming a coating film for internal electrode formation by printing, a known conductive paste containing a conductive material, a binder, and a solvent, and optionally containing a dielectric material, can be used. For example, the electrode layer slurry composition of the present invention can be used as such a conductive paste.

[0092] (electrode layer) The electrode layer of the present invention comprises a coating film using the slurry composition of the present invention described above. The slurry composition of the present invention used for the coating film of the electrode layer is typically a slurry composition for electrode layers. Here, the coating film (hereinafter sometimes referred to as "electrode film") of the electrode layer of the present invention uses the slurry composition of the present invention, which has excellent dispersion stability and drying speed, and therefore has excellent uniformity of film thickness and effectively reduces the amount of water in the coating film. Furthermore, since the electrode layer of the present invention comprises an electrode film using the slurry composition of the present invention, its hygroscopicity is reduced.

[0093] The electrode film is not particularly limited, but may, for example, be a dried film obtained by partially or completely removing the solvent from the electrode film. That is, the electrode film comprises a dielectric material, a polymer, and a conductive material, and may optionally contain a solvent and other components.

[0094] Each component contained in the electrode film is the same as that contained in the slurry composition described above, and the preferred ratio of each component is the same as the preferred ratio of each component in the slurry composition.

[0095] The thickness of the electrode film is preferably 0.1 μm or more, more preferably 0.5 μm or more, preferably 10 μm or less, and more preferably 5 μm or less.

[0096] Here, the electrode layer of the present invention has two embodiments: an internal electrode layer and an external electrode layer. The internal electrode layer forms the internal electrodes of the multilayer ceramic capacitor, and the external electrode layer forms the external electrodes of the multilayer ceramic capacitor. In the following description, we will explain the case where the electrode layer is an internal electrode layer as an example, but the present invention is not limited to the example below.

[0097] The method for producing the coating film on the internal electrode layer (hereinafter sometimes referred to as the "internal electrode film") is not particularly limited. For example, it can be produced by first preparing a release substrate with a dielectric-forming coating film, then applying the electrode layer slurry composition of the present invention onto the dielectric-forming coating film, and then drying the resulting internal electrode film as desired. Here, the same release substrate as described in the "dielectric layer" section above can be used as the release substrate. The dielectric film for forming the dielectric material can be prepared by applying a known slurry containing a dielectric material, a binder, and a solvent onto a release substrate, and then drying the formed film as appropriate. For example, the slurry composition for dielectric layers of the present invention described above can be used as the slurry.

[0098] The method for applying the slurry composition for the electrode layer onto the release substrate is not particularly limited, and known application methods include using an applicator or various roll coaters such as gravure coaters and comma coaters (registered trademarks).

[0099] The drying method for the internal electrode film is not particularly limited, and known drying methods using a hot air dryer can be cited as examples. The drying conditions can be appropriately set according to the solvent content in the internal electrode film, the thickness of the internal electrode film, etc., but the drying temperature is usually between 80°C and 150°C, and the drying time is usually between 3 minutes and 60 minutes.

[0100] (Multilayer ceramic capacitor) The multilayer ceramic capacitor of the present invention comprises a dielectric, an internal electrode, and an external electrode. In the multilayer ceramic capacitor of the present invention, the dielectric is made of the dielectric layer of the present invention described above, or at least one of the internal electrode and the external electrode is made of the electrode layer of the present invention described above. Here, since the multilayer ceramic capacitor of the present invention uses the dielectric layer or electrode layer of the present invention, which has excellent uniformity of film thickness, variations in performance are suppressed. Furthermore, the multilayer ceramic capacitor of the present invention has excellent performance because it uses a dielectric layer or electrode layer of the present invention in which the amount of moisture in the coated film is effectively reduced. Furthermore, the multilayer ceramic capacitor of the present invention has excellent performance because it uses a dielectric layer or electrode layer of the present invention that has reduced hygroscopicity.

[0101] Specifically, the multilayer ceramic capacitor of the present invention may be any of the following (1) to (6). (1) The dielectric material is made of the dielectric layer of the present invention, and the internal electrode and external electrode are made of known electrode layers. (2) The dielectric material is made of the dielectric layer of the present invention, the internal electrode is made of the electrode layer of the present invention, and the external electrode is made of a known electrode layer. (3) The dielectric material is made of the dielectric layer of the present invention, the internal electrode is made of a known electrode layer, and the external electrode is made of the electrode layer of the present invention. (4) The dielectric is made of a known dielectric layer, the internal electrode is made of the electrode layer of the present invention, and the external electrode is made of a known electrode layer. (5) The dielectric is made of a known dielectric layer, the internal electrode is made of a known electrode layer, and the external electrode is made of the electrode layer of the present invention. (6) The dielectric material is made of the dielectric layer of the present invention, and the internal electrode and external electrode are made of the electrode layer of the present invention.

[0102] Herein, the multilayer ceramic capacitor of the present invention is not particularly limited as long as the dielectric material is made of the dielectric layer of the present invention, or at least one of the internal electrode and the external electrode is made of the electrode layer of the present invention. For example, the dielectric material may be made by sintering the dielectric layer of the present invention (sintered product), the internal electrode may be made by sintering the electrode layer of the present invention (sintered product), or the external electrode may be made by sintering the electrode layer of the present invention (sintered product).

[0103] In the following description, an example of the multilayer ceramic capacitor of the present invention will be explained with reference to Figure 1, but the multilayer ceramic capacitor of the present invention is not limited to this example.

[0104] Figure 1 is a schematic cross-sectional view showing an example of a multilayer ceramic capacitor of the present invention. The multilayer ceramic capacitor 10 shown in Figure 1 comprises alternately stacked layered dielectrics 11 and layered internal electrodes 12, and a pair of external electrodes 13 are provided on the outside of the dielectrics 11 and internal electrodes 12. One of a pair of internal electrodes 12 adjacent to each other along the stacking direction, with the dielectric 11 in between, is electrically connected to one of a pair of external electrodes 13 inside the multilayer ceramic capacitor 10, and the other of a pair of internal electrodes 12 adjacent to each other along the stacking direction, with the dielectric 11 in between, is electrically connected to the other of a pair of external electrodes 13 inside the multilayer ceramic capacitor 10. As a result, the space between a pair of external electrodes 13 has a structure in which multiple capacitor elements are electrically connected in parallel. Note that the interface between dielectric layers that may be formed when the dielectric layers of the present invention are stacked is not shown in Figure 1 because the dielectric layers may merge and disappear due to sintering.

[0105] Multilayer ceramic capacitors are not particularly limited and can be manufactured by conventionally known methods. For example, a multilayer ceramic capacitor can be manufactured by stacking multiple layers of internal electrode layers that can serve as internal electrodes and dielectric layers that can serve as dielectrics, with the dielectric layers and internal electrode layers alternating, and then heating and pressing these layers together to create a laminate. Binder components and the like contained in this laminate are removed by thermal decomposition (degreasing treatment), and then the laminate is sintered. Finally, external electrodes are formed on the end faces of the sintered ceramic material obtained by sintering.

[0106] Degreasing is typically performed in a nitrogen atmosphere at a temperature between 300°C and 500°C. The degreasing time is usually between 1 and 5 hours. The binder component content of the laminate after degreasing is typically 50 ppm or less.

[0107] Sintering of degreased laminates typically occurs when the oxygen partial pressure is 10 -9 ~10 -12The process is carried out in a reducing atmosphere such as H2-N2-H2O gas at MPa, at a temperature between 1000°C and 1500°C. The sintering time for the laminate is typically between 1 hour and 30 hours.

[0108] External electrodes can be formed by applying an external electrode material to the end face of a sintered ceramic product and then baking it. This allows for the creation of a multilayer ceramic capacitor, such as the one shown in Figure 1. For example, a Cu paste containing glass frit can be used as the material for the external electrode. Alternatively, the electrode layer slurry composition of the present invention described above can also be used as the material for the external electrode. The baking process is typically carried out in a nitrogen atmosphere at a temperature between 500°C and 1500°C. The surface of the external electrode can also be plated with materials such as Ni or Sn. [Examples]

[0109] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" used to express quantities refer to mass unless otherwise specified. Furthermore, in polymers produced by polymerizing multiple types of monomers, the proportion of a monomer unit formed by polymerizing a certain monomer in the polymer is, unless otherwise specified, usually equal to the ratio of that monomer to the total monomers used in the polymerization of that polymer (the initial charge ratio). Furthermore, various evaluations were conducted using the following methods.

[0110] <Dispersion stability> The viscosity η0 of the slurry compositions prepared in the examples and comparative examples was measured using a B-type viscometer at 25°C and a rotation speed of 60 rpm. The slurry compositions were then left to stand at 25°C for 7 days, and the viscosity η1 was measured again in the same manner as above. Using the measured viscosities η0 and η1, the viscosity change rate α was calculated according to the following formula (2). Viscosity change rate α(%)=(η1 / η0)×100 (2) The dispersion stability was then evaluated according to the following criteria: A viscosity change rate α of 100% or more, and the closer the viscosity change rate α is to 100%, the less likely the slurry composition is to undergo viscosity changes over time, indicating excellent dispersion stability. A: Viscosity change rate α is between 100% and less than 150% B: Viscosity change rate α is 150% or more and less than 200% C: Viscosity change rate α is 200% or more

[0111] <Drying speed> The slurry compositions obtained in the examples and comparative examples were coated onto a PET substrate to a thickness of 20 μm, and the film weight W0 before drying was measured. Next, the obtained film was dried at 100°C for 1 minute, and the film weight W1 after drying was measured. The weight loss rate of the film before and after drying ("(W0-W1) / W1×100(%)") was calculated, and the drying speed was evaluated according to the following criteria. A larger weight loss rate indicates a better drying speed. A: Over 70% B: 60% to less than 70% C: Less than 60%

[0112] <Hygroscopicity> The release substrates with dielectric layers prepared in the examples and comparative examples were cut to a size of 10 cm x 10 cm to serve as test specimens. These test specimens were left at a temperature of 25°C and a humidity of 50% for 24 hours, and then the moisture content (W0) of the test specimens was measured using a coulometric titration type moisture meter by the Karl Fischer method (JIS K-0068 (2001) moisture vaporization method, vaporization temperature 150°C). Subsequently, the test specimens were stored at 25°C, 80% humidity for 12 hours, and the moisture content (W1) of the test specimens was measured using a coulometric titration moisture meter according to the Karl Fischer method described above. The change in moisture content (ΔW) was then calculated according to the following formula (2). ΔW(%) = (W1 / W0) × 100 (2) Using the above ΔW, the hygroscopicity of the dielectric layer was evaluated according to the following criteria. A smaller ΔW indicates a reduced hygroscopicity of the dielectric layer. A: ΔW is between 100% and 120% B:ΔW is between 120% and 150%. C:ΔW is over 150%

[0113] (Example 1) <Preparation of Slurry Composition> 100 parts of barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., "BT-01") with a volume-average particle size (d50) of 0.1 μm as a dielectric material, 8 parts of polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., "BL-2H") as a polymer (solid content), 3.2 parts of dioctyl phthalate (DOP) as a plasticizer (40 parts per 100 parts of polymer), and 90.6 parts of cyclopentanone and 22.6 parts of ethanol as solvents were mixed with 100 parts of zirconia beads (manufactured by Nikkatoh Co., Ltd.) with a particle size of 0.1 mm, using a bead mill (manufactured by AIMEX Co., Ltd., "RMB-01") and stirred at 500 rpm for 2 hours. The zirconia beads were filtered off to prepare a slurry composition with a solid content concentration of 48.60%. The dispersion stability and drying rate of the obtained slurry composition were evaluated. The results are shown in Table 1.

[0114] <Fabrication of dielectric layers> The slurry composition obtained above was applied to a release-treated film (Lintec Corporation, PET38AL-5) measuring 100 mm in width and 100 mm in length using a gravure coater to form a coated film such that the thickness of the green sheet after drying was approximately 1.0 μm. Then, it was dried in an oven at 100°C for 5 minutes to obtain a release substrate with a dielectric layer (ceramic green sheet method). The hygroscopic properties of the obtained release substrate with dielectric layer were evaluated. The results are shown in Table 1.

[0115] (Example 2) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 56.6 parts of cyclopentanone and 56.6 parts of ethanol were used as solvents. The results are shown in Table 1.

[0116] (Example 3) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 113.2 parts of cyclopentanone were used as the solvent. The results are shown in Table 1.

[0117] (Example 4) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 90.6 parts of cyclobutanone and 22.6 parts of ethanol were used as solvents. The results are shown in Table 1.

[0118] (Example 5) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 90.6 parts of cyclopentyl methyl ether and 22.6 parts of ethanol were used as solvents. The results are shown in Table 1.

[0119] (Example 6) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 8 parts of PVA (Denka Co., Ltd., Denka Poval® B-33) were used as the polymer in terms of solid content. The results are shown in Table 1.

[0120] (Example 7) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 8 parts of acrylic polymer A, obtained by the following method, were used as the polymer by solid content. The results are shown in Table 1.

[0121] <Preparation of Acrylic Polymer A> In a 5 MPa pressure vessel equipped with a stirrer, 25 parts of methacrylic acid (hydrophilic group-containing structural unit) and 75 parts of n-butyl acrylate ((meth)acrylate alkyl ester monomer) were added as monomer compositions, along with 0.3 parts of tert-dodecyl mercaptan as a molecular weight modifier, 0.6 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of deionized water, and 1 part of potassium persulfate as a polymerization initiator. After thorough stirring, the mixture was heated to 60°C to start polymerization. When the polymerization conversion rate reached 96%, the mixture was cooled to stop the reaction, yielding an aqueous dispersion of acrylic polymer A with a solid content of 40%. Next, methanol was added to coagulate the polymer, which was then separated using filter paper. The polymer was then vacuum-dried at 60°C for 24 hours to obtain acrylic polymer A powder.

[0122] (Example 8) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 8 parts of acrylic polymer B, obtained by the following method, were used as the polymer by solid content. The results are shown in Table 1.

[0123] <Preparation of Acrylic Polymer B> In a 5 MPa pressure vessel equipped with a stirrer, 5 parts of methacrylic acid (hydrophilic group-containing structural unit), 75 parts of n-butyl acrylate ((meth)acrylate alkyl ester monomer), and 20 parts of methyl methacrylate ((meth)acrylate alkyl ester monomer) were added as monomer compositions, along with 0.3 parts of tert-dodecyl mercaptan as a molecular weight modifier, 0.6 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of deionized water, and 1 part of potassium persulfate as a polymerization initiator. After thorough stirring, the mixture was heated to 60°C to start polymerization. When the polymerization conversion rate reached 96%, the mixture was cooled to stop the reaction, yielding an aqueous dispersion of acrylic polymer B with a solid content of 40%. Next, methanol was added to solidify the polymer, which was then separated using filter paper. The polymer was then vacuum-dried at 60°C for 24 hours to obtain acrylic polymer B powder.

[0124] (Comparative Example 1) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 50.9 parts of cyclopentanone and 62.3 parts of ethanol were used as solvents. The results are shown in Table 1.

[0125] (Comparative Example 2) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 90.9 parts of toluene and 22.2 parts of ethanol were used as solvents. The results are shown in Table 1.

[0126] In Tables 1 and 2 shown below, "PVB" refers to polyvinyl butyral. "PVA" refers to polyvinyl alcohol. "ACL" indicates an acrylic polymer. "VA" stands for vinyl alcohol unit. "MAA" indicates the methacrylic acid unit. "CPN" stands for cyclopentanone. "CPME" indicates cyclopentyl methyl ether. "CBN" stands for cyclobutanone.

[0127] [Table 1]

[0128] As is clear from Table 1, the slurry compositions of the examples exhibit excellent dispersion stability and drying speed. [Industrial applicability]

[0129] According to the present invention, a slurry composition with excellent dispersion stability and drying speed can be provided. Furthermore, according to the present invention, a dielectric layer comprising a coated film using the above-mentioned slurry composition can be provided. Furthermore, according to the present invention, it is possible to provide a multilayer ceramic capacitor equipped with a dielectric using the above-mentioned dielectric layer. [Explanation of Symbols]

[0130] 10: Multilayer ceramic capacitor 11: Dielectrics 12: Internal electrode 13: External electrode

Claims

1. A slurry composition comprising a dielectric material, a polymer, and a solvent, The aforementioned solvent is of the following formula (A): R １ =O (A) [In formula (A), R １ It is a divalent alicyclic hydrocarbon group. Ketone solvent A, represented by the following formula (B): R ２ -O-R ３ (B) [In formula (B), R ２ is a monovalent alicyclic hydrocarbon group, and R ３ is a monovalent hydrocarbon group.] It comprises at least one of the ether solvents B represented by, A slurry composition in which the total proportion of the ketone solvent A and the ether solvent B in the entire solvent is 50% by mass or more.

2. The slurry composition according to claim 1, wherein the dielectric material has a perovskite structure.

3. The slurry composition according to claim 1, wherein the polymer contains hydrophilic group-containing structural units.

4. The aforementioned R １ and R ２ The slurry composition according to claim 1, wherein the alicyclic hydrocarbon group has a five-membered ring.

5. The slurry composition according to claim 1, further comprising a conductive material.

6. A dielectric layer comprising a coated film using the slurry composition described in claim 1.

7. An electrode layer comprising a coating film using the slurry composition described in claim 5.

8. A multilayer ceramic capacitor comprising a dielectric, an internal electrode, and an external electrode, The dielectric is made using the dielectric layer described in claim 6, or A multilayer ceramic capacitor in which at least one of the internal electrode and the external electrode is made of the electrode layer described in claim 7.

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