Binder composition for ceramic capacitors, slurry composition for ceramic capacitors, dielectric layer for ceramic capacitors, electrode layer for ceramic capacitors, and ceramic capacitors

Abstract

To provide a binder composition for ceramic capacitors that can impart excellent foam resistance to slurry compositions and excellent wettability and blocking resistance to dielectric layers and the like. [Solution] The present invention relates to a binder composition for ceramic capacitors comprising a copolymer containing (meth)acrylic acid ester monomer units, hydrophilic group-containing monomer units having at least one selected from the group consisting of carboxyl groups, hydroxyl groups, and phosphate groups, and surfactant units having sulfonic acid groups, and a solvent, wherein the proportion of the surfactant units in the copolymer is 0.1% by mass or more and 5.0% by mass or less, when the total repeating units in the copolymer are considered to be 100% by mass.

Description

[Technical Field]

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

[0002] Ceramic capacitors are widely used as one of the electronic components mounted in various electronic devices. Furthermore, with the miniaturization and multilayering of electronic components, multilayer electronic components such as multilayer circuit boards, multilayer coils, and multilayer ceramic capacitors are also being 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, development has been progressing on binders and other components included in slurry compositions used in the manufacture of dielectric layers and other parts.

[0005] For example, Patent Document 1 proposes an inorganic sintered body manufacturing binder that, when used as a binder for manufacturing ceramic green sheets, can achieve high porosity and produce ceramic green sheets that are less prone to defects such as cracks during the manufacturing of sintered bodies, and is a binder with excellent thermal decomposition properties, comprising a binder resin composition having a predetermined gel fraction and containing a predetermined composite resin. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-165230 [Overview of the project] [Problems that the invention aims to solve]

[0007] Here, from the viewpoint of densifying the dielectric layer and electrode layer (hereinafter, the dielectric layer and electrode layer may be collectively referred to as "dielectric layer, etc.") to impart superior performance to the ceramic capacitor, it is desirable that the slurry composition used to form the dielectric layer, etc. suppresses the generation of foam.

[0008] Furthermore, while another slurry composition can be applied to a dielectric layer formed using a slurry composition to form a desired coating film, it is desirable that the dielectric layer has excellent wettability from the viewpoint of ensuring good adhesion between layers and imparting excellent performance to the resulting ceramic capacitor.

[0009] Furthermore, after forming a dielectric layer on one side of the release substrate, the release substrate with the dielectric layer formed on it is usually wound into a roll. When wound into a roll, the dielectric layer becomes in close contact with the surface of the release substrate on the side where the dielectric layer is not formed (hereinafter sometimes referred to as the "back surface of the release substrate"). If stored in this state, the dielectric layer may become fixed to the back surface of the release substrate (so-called blocking), which may cause the dielectric layer to break or fracture.

[0010] However, conventional binders had room for improvement in terms of providing excellent foam resistance to slurry compositions using the binder, and excellent wettability and blocking resistance to dielectric layers formed using the slurry compositions.

[0011] Therefore, the present invention aims to provide a binder composition for ceramic capacitors that can impart excellent foaming resistance to slurry compositions and excellent wettability and blocking resistance to dielectric layers and the like. Furthermore, the present invention aims to provide a slurry composition for ceramic capacitors that includes the above-mentioned binder composition for ceramic capacitors. Furthermore, the present invention aims to provide a dielectric layer for ceramic capacitors and an electrode layer for ceramic capacitors, which include a coating film using the above-mentioned slurry composition for ceramic capacitors. Furthermore, the present invention aims to provide a ceramic capacitor comprising a dielectric made using the above-mentioned dielectric layer for ceramic capacitors, or an electrode made using the above-mentioned electrode layer for ceramic capacitors. [Means for solving the problem]

[0012] The inventors diligently conducted research with the aim of solving the above problems. The inventors then discovered that the above problems can be solved if the binder composition for ceramic capacitors comprises a copolymer containing (meth)acrylic acid ester monomer units, a hydrophilic group-containing monomer unit having at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and a phosphate group, and a surfactant unit having a sulfonic acid group, and a solvent, wherein the proportion of surfactant units having a sulfonic acid group in the copolymer is within a predetermined range. Based on this discovery, the inventors completed the present invention.

[0013] That is, the present invention aims to advantageously solve the above problems. [1] The present invention provides a binder composition for a ceramic capacitor, comprising a copolymer containing a (meth)acrylate monomer unit, a hydrophilic group-containing monomer unit having at least one selected from the group consisting of a carboxy group, a hydroxy group, and a phosphate group, and a surfactant unit having a sulfonic acid group, and a solvent, wherein the proportion of the surfactant unit in the copolymer is 0.1% by mass or more and 5.0% by mass or less based on 100% by mass of all the repeating units in the copolymer. With the above-described binder composition for a ceramic capacitor, excellent anti-foaming properties can be imparted to the slurry composition, and excellent wetting properties and anti-blocking properties can be imparted to the dielectric layer and the like. In the present specification, the content ratio of various repeating units (monomer units) in the (co)polymer can be measured using a nuclear magnetic resonance (NMR) method such as H-NMR. 1 In the present specification, “(meth)acryl” means acrylic and / or methacrylic.

[0014] [2] In the binder composition for a ceramic capacitor described in [1] above, the proportion of the hydrophilic group-containing monomer unit in the copolymer is preferably 10.0% by mass or more and 80.0% by mass or less based on 100% by mass of all the repeating units in the copolymer. If the proportion of the hydrophilic group-containing monomer unit in the copolymer is at least the above lower limit, the wetting properties of the dielectric layer and the like can be effectively improved. On the other hand, if the proportion of the hydrophilic group-containing monomer unit in the copolymer is at most the above upper limit, the anti-blocking properties of the dielectric layer and the like can be effectively improved.

[0015] [3] In the binder composition for a ceramic capacitor described in [1] or [2] above, the proportion of the (meth)acrylate monomer unit in the copolymer is preferably 15.0% by mass or more and 89.9% by mass or less based on 100% by mass of all the repeating units in the copolymer. If the proportion of the (meth)acrylic acid ester monomer unit in the copolymer is at least the above lower limit, the blocking resistance of the dielectric layer or the like can be effectively improved. On the other hand, if the proportion of the (meth)acrylic acid ester monomer unit in the copolymer is at most the above upper limit, the wettability of the dielectric layer or the like can be effectively improved.

[0016] [4] In the binder composition for a ceramic capacitor according to any one of the above [1] to [3], the glass transition temperature of the copolymer is preferably 30°C or higher and 100°C or lower. If the glass transition temperature of the copolymer is within the above range, the performance of the ceramic capacitor can be effectively improved. In the present specification, the glass transition temperature of the (co)polymer can be measured according to the method described in the examples.

[0017] [5] In the binder composition for a ceramic capacitor according to any one of the above [1] to [4], the weight average molecular weight of the copolymer is preferably 5,000 or higher and 2,000,000 or lower. If the weight average molecular weight of the copolymer is at least the above lower limit, the blocking resistance of the dielectric layer or the like can be effectively improved. On the other hand, if the weight average molecular weight of the copolymer is at most the above upper limit, the wettability of the dielectric layer or the like can be effectively improved. In the present specification, the "weight average molecular weight" of the copolymer can be measured using the method described in the examples of the present specification.

[0018] [6] In the binder composition for a ceramic capacitor according to any one of the above [1] to [5], the solvent is preferably water. If the solvent is water, the foam resistance of the slurry composition can be improved. Also, the wettability and blocking resistance of the dielectric layer or the like can be improved.

[0019] Further, the present invention aims to advantageously solve the above problems, and [7] the present invention is a slurry composition for a ceramic capacitor containing the binder composition for a ceramic capacitor according to any one of the above [1] to [6] and a dielectric material. A slurry composition for ceramic capacitors as described above offers excellent resistance to foaming, as well as excellent wettability and blocking properties for the dielectric layer and the like.

[0020] [8] The slurry composition for ceramic capacitors described in [7] above preferably further contains a water-insoluble polymer. If the slurry composition for ceramic capacitors further contains a water-insoluble polymer, its foaming resistance can be improved. Furthermore, the wettability of the dielectric layer and other components can be improved. In this specification, a polymer is said to be "water-insoluble" if, when 0.5 g of the polymer is dissolved in 100 g of water at a temperature of 25°C, the insoluble content is 90% by mass or more.

[0021] Furthermore, the present invention aims to advantageously solve the above problems, and [9] the present invention is a dielectric layer for a ceramic capacitor comprising a coating film using the ceramic capacitor slurry composition of [7] or [8] described above. The coating film on the dielectric layer for ceramic capacitors as described above exhibits excellent density, wettability, and blocking resistance.

[0022] Furthermore, the present invention aims to advantageously solve the above problems, and

[10] the present invention is an electrode layer for a ceramic capacitor comprising a coating film using the ceramic capacitor slurry composition of [7] or [8] above. The coating film on the electrode layer for ceramic capacitors as described above exhibits excellent density, wettability, and blocking resistance.

[0023] Furthermore, the present invention aims to advantageously solve the above problems,

[11] and the present invention is a ceramic capacitor comprising a dielectric and an electrode, wherein the dielectric is made of the dielectric layer for ceramic capacitors described in [9] above, or the electrode is made of the electrode layer for ceramic capacitors described in

[10] above. The ceramic capacitors described above offer excellent performance and productivity. [Effects of the Invention]

[0024] According to the present invention, it is possible to provide a binder composition for ceramic capacitors that can impart excellent foaming resistance to slurry compositions and excellent wettability and blocking resistance to dielectric layers and the like. Furthermore, according to the present invention, a slurry composition for ceramic capacitors containing the above-mentioned binder composition for ceramic capacitors can be provided. Furthermore, according to the present invention, it is possible to provide a dielectric layer for a ceramic capacitor and an electrode layer for a ceramic capacitor that include a coating film using the above-mentioned slurry composition for ceramic capacitors. Furthermore, according to the present invention, it is possible to provide a ceramic capacitor comprising a dielectric made using the above-mentioned dielectric layer for ceramic capacitors, or an electrode made using the above-mentioned electrode layer for ceramic capacitors. [Brief explanation of the drawing]

[0025] [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]

[0026] Embodiments of the present invention will be described in detail below.

[0027] Here, the binder composition for ceramic capacitors of the present invention (hereinafter sometimes simply referred to as "binder composition") can be used to prepare the slurry composition for ceramic capacitors of the present invention (hereinafter sometimes simply referred to as "slurry composition"). Furthermore, the slurry composition of the present invention can be used to form a dielectric layer for ceramic capacitors (hereinafter sometimes simply referred to as "dielectric layer") or an electrode layer for ceramic capacitors (hereinafter sometimes simply referred to as "electrode layer") used in the manufacture of ceramic capacitors. Furthermore, the dielectric layer of the present invention can be used to form the dielectric material of the ceramic capacitor of the present invention. Furthermore, the electrode layer of the present invention can be used to form the electrodes of the ceramic capacitor of the present invention.

[0028] (Binder composition for ceramic capacitors) The binder composition for ceramic capacitors of the present invention comprises a copolymer containing (meth)acrylic acid ester monomer units, hydrophilic group-containing monomer units having at least one selected from the group consisting of carboxyl groups, hydroxyl groups, and phosphate groups, and surfactant units having sulfonic acid groups, and a solvent. In the binder composition of the present invention, the proportion of surfactant units in the copolymer is 0.1% by mass or more and 5.0% by mass or less, when the total repeating units (total monomer units) in the copolymer are taken as 100% by mass. The binder composition described above can impart excellent foam resistance to the slurry composition, as well as excellent wettability and blocking resistance to the dielectric layer and the like. The reason for this is presumed to be as follows.

[0029] While surfactants can be added to properly disperse the binder (polymer, etc.) and dielectric material in a slurry composition, the presence of surfactants alone in the slurry composition can cause the slurry composition to foam easily due to the action of the surfactant. Furthermore, in dielectric layers formed using a slurry composition containing surfactants, the surfactant may migrate to the surface of the dielectric layer (so-called migration), potentially leading to non-uniform wettability and blocking. In the binder composition of the present invention, by including surfactant units having sulfonic acid groups in a predetermined proportion in addition to (meth)acrylic acid ester monomer units and predetermined hydrophilic group-containing monomer units in the copolymer, it is presumed that foaming of the slurry composition can be suppressed, and the decrease in wettability and the occurrence of blocking in the dielectric layer can be suppressed.

[0030] Here, the binder composition of the present invention may contain a surfactant to the extent that it does not impair the objective of the present invention, but the amount of surfactant in the binder composition is preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, even more preferably 0.01 parts by mass or less, even more preferably 0.001 parts by mass or less, and particularly preferably 0 parts by mass, based on 100 parts by mass of the copolymer. In other words, it is particularly preferable that the binder composition of the present invention does not contain a surfactant. Examples of surfactants include sodium dodecylbenzenesulfonate.

[0031] The binder composition of the present invention may optionally contain components other than the copolymer, solvent, and surfactant (hereinafter sometimes referred to as "other components"). The binder composition of the present invention typically does not contain the dielectric material described later.

[0032] <Copolymer> The copolymer contained in the binder composition is a component that can function as a dispersant in the slurry composition, and is also a component that can function as a binder that holds materials contained in the dielectric layer, etc., so as not to detach from the dielectric layer, etc. The copolymer contains (meth)acrylic acid ester monomer units, hydrophilic group-containing monomer units having at least one selected from the group consisting of carboxyl groups, hydroxyl groups, and phosphate groups (hereinafter sometimes simply referred to as "hydrophilic group-containing monomer units"), and surfactant units having sulfonic acid groups (hereinafter sometimes simply referred to as "surfactant units"), and may optionally contain monomer units other than (meth)acrylic acid ester monomer units, hydrophilic group-containing monomer units, and surfactant units (hereinafter sometimes referred to as "other monomer units A").

[0033] <<(meth)acrylic acid ester monomer unit>> A (meth)acrylic acid monomer unit is a monomer unit that can be formed by (meth)acrylic acid monomers. Examples of (meth)acrylic acid monomers include alkyl (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate; and alkoxy (meth)acrylate monomers such as 2-methoxyethyl (meth)acrylate and 2-ethoxyethyl (meth)acrylate. These may be used individually or in combination of two or more types. Among the above, alkyl (meth)acrylate monomers are preferred, and ethyl (meth)acrylate and n-butyl (meth)acrylate are more preferred. That is, the (meth)acrylate monomer unit is preferably an alkyl (meth)acrylate monomer unit, and more preferably at least one of an ethyl (meth)acrylate unit and an n-butyl (meth)acrylate unit. In this specification, "(meth)acrylate" means acrylate and / or methacrylate.

[0034] The proportion of (meth)acrylic acid ester monomer units in the copolymer is preferably 15.0% by mass or more, more preferably 27.0% by mass or more, even more preferably 38.0% by mass or more, preferably 89.9% by mass or less, more preferably 84.8% by mass or less, and even more preferably 79.7% by mass or less, when the total repeating units (total monomer units) in the copolymer are taken as 100% by mass. If the proportion of (meth)acrylic acid ester monomer units in the copolymer is above the lower limit mentioned above, the blocking resistance of the dielectric layer and the like can be effectively improved. On the other hand, if the proportion of (meth)acrylic acid ester monomer units in the copolymer is below the above upper limit, the wettability of the dielectric layer and the like can be effectively improved.

[0035] <<Hydrophilic group-containing monomer unit>> A hydrophilic group-containing monomer unit has at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and a phosphate group. Furthermore, a hydrophilic group-containing monomer unit can be formed from a monomer having at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and a phosphate group. Furthermore, the carboxyl group, hydroxyl group, and phosphate group of the hydrophilic group-containing monomer unit may be partially or entirely in the form of a salt with an alkali metal or ammonia. Note that the monomer units containing hydrophilic groups are not included in the (meth)acrylic acid ester monomer units described above.

[0036] Hydrophilic group-containing monomer units are preferable because they can impart excellent foam resistance to slurry compositions and excellent wettability and blocking resistance to dielectric layers, etc., and therefore, monomer units having a carboxyl group as the hydrophilic group (hereinafter sometimes referred to as "carboxyl group-containing monomer units") are preferable.

[0037] Examples of carboxyl group-containing monomers that can form carboxyl group-containing monomer 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.

[0038] Examples of hydroxyl group-containing monomers that can form monomer units having a hydroxyl group as a hydrophilic group (hereinafter sometimes referred to as "hydroxyl group-containing monomer units") 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 may be used individually or in combination. In this specification, "(meth)acryloyl" means acryloyl and / or methacryloyl, and "(meth)allyl" means allyl and / or methallyl.

[0039] Examples of phosphate-containing monomers that can form monomer units having a phosphate group as a hydrophilic group (hereinafter sometimes referred to as "phosphate-containing monomer 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 of multiple types.

[0040] The proportion of hydrophilic group-containing monomer units in the copolymer is preferably 10.0% by mass or more, more preferably 15.0% by mass or more, even more preferably 20.0% by mass or more, preferably 80.0% by mass or less, more preferably 70.0% by mass or less, and even more preferably 60.0% by mass or less, when the total repeating units (total monomer units) in the copolymer are taken as 100% by mass. If the proportion of hydrophilic group-containing monomer units in the copolymer is above the lower limit mentioned above, the wettability of the dielectric layer and the like can be effectively improved. On the other hand, if the proportion of hydrophilic group-containing monomer units in the copolymer is below the above upper limit, the blocking resistance of the dielectric layer and the like can be effectively improved.

[0041] <<Surfactant Units>> The surfactant unit has a sulfonic acid group. Furthermore, the surfactant unit can be formed from a reactive surfactant that can copolymerize with other monomers capable of forming copolymers. Here, a reactive surfactant capable of forming a surfactant unit refers to a monomer that has polymerizable groups that can copolymerize with other monomers, and also has surface-active groups (i.e., hydrophilic and hydrophobic groups). The surfactant unit formed by polymerization of the reactive surfactant constitutes part of the copolymer contained in the binder composition and can function as a surfactant. Note that surfactant units containing sulfonic acid groups are not included in the (meth)acrylic acid ester monomer units and hydrophilic group-containing monomer units described above.

[0042] Reactive surfactants typically have polymerizable unsaturated groups, and these polymerizable unsaturated groups may also act as hydrophobic groups after polymerization. Examples of polymerizable unsaturated groups include vinyl groups, allyl groups, vinylidene groups, propenyl groups, isopropenyl groups, and isobutylidene groups. There may be one type of such polymerizable unsaturated group, or two or more types.

[0043] Reactive surfactants may have a sulfonic acid group as a hydrophilic group, and optionally a carboxyl group or a hydroxyl group as a hydrophilic group. Alternatively, reactive surfactants may have only a sulfonic acid group as a hydrophilic group. Furthermore, the hydrophilic group of the reactive surfactant may be partially or entirely in the form of a salt with an alkali metal or ammonia.

[0044] In the following, reactive surfactant A and reactive surfactant B are described as specific examples of reactive surfactants, but the reactive surfactants used in the copolymer of the present invention are not limited to these. Furthermore, it is preferable to use reactive surfactant A, described later, as the reactive surfactant, since it can improve the foaming resistance of the slurry composition. That is, it is preferable that the surfactant units in the copolymer are surfactant units formed from reactive surfactant A, described later.

[0045] [Reactive surfactant A] Reactive surfactant A is compound (I) represented by the following formula (I). [ka]

[0046] R in equation (I) 1 This represents a hydrogen atom, a methyl group, or an ethyl group, and it is preferable that it represents a methyl group.

[0047] R in equation (I) 2 This represents a -Si-O- group, a methylene group, an ethylene group, or a phenylene group, with the ethylene group being preferred.

[0048] R in formula (I) 3 represents a hydrogen atom, a methyl group, or an ethyl group, and preferably represents a methyl group.

[0049] R in formula (I) 4 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0050] M in formula (I) 1 represents an alkali metal atom or a quaternary ammonium salt (NH4 + ), and preferably represents a quaternary ammonium salt.

[0051] l in formula (I) is an integer of 0 or more and 5 or less, and preferably 0.

[0052] m in formula (I) is an integer of 1 or more and 100 or less, and preferably an integer of 2 or more and 50 or less.

[0053] n in formula (I) is an integer of 1 or more and 100 or less, and preferably an integer of 2 or more and 50 or less.

[0054] Examples of the compound (I) include ammonium polyoxyalkylene alkenyl ether sulfate (such as "Latemul PD-104" manufactured by Kao Corporation).

[0055] [Reactive surfactant B] The reactive surfactant B is a compound (II) represented by the following formula (II). [Chemical formula]

[0056] R in formula (II) 5 represents a hydrogen atom, a methyl group, or an ethyl group, and preferably represents a hydrogen atom.

[0057] R in formula (II) 6This represents a methylene group, an ethylene group, or a phenylene group, with a methylene group being preferred.

[0058] R in equation (II) 7 This represents a methylene group, an ethylene group, or a phenylene group, with a methylene group being preferred.

[0059] R in equation (II) 8 This represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0060] M in equation (II) 2 This is an alkali metal atom or a quaternary ammonium salt (NH4 + It is preferable that the alkali metal atom is represented as ) and that the alkali metal is sodium.

[0061] Examples of compound (II) include sodium alkylallyl sulfosuccinate (such as "Eleminol JS-20" manufactured by Sanyo Chemical Industries, Ltd.).

[0062] [Percentage of surfactant units] The proportion of surfactant units in the copolymer must be 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and must be 5.0% by mass or less, preferably 3.0% by mass or less, and more preferably 2.0% by mass or less, based on the total repeating units (total monomer units) in the copolymer being 100% by mass. If the proportion of surfactant units in the copolymer is above the lower limit mentioned above, the wettability of the dielectric layer and the like can be effectively improved. On the other hand, if the proportion of surfactant units in the copolymer is below the above upper limit, the blocking resistance of the dielectric layer and the like can be effectively improved.

[0063] <<Other monomer units A>> Other monomer units A that may be optionally contained in the copolymer are not particularly limited. Examples of monomer units A that can form other monomer units A 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; and amino group-containing monomers such as aminoethyl vinyl ether and dimethylaminoethyl vinyl ether. These other monomers A may be used individually or in combination of two or more types.

[0064] The proportion of other monomer units A in the copolymer is preferably 5.0% by mass or less, more preferably 1.0% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0% by mass, when the total repeating units (total monomer units) contained in the copolymer are taken as 100% by mass. In other words, it is particularly preferable that the copolymer does not contain other monomer units A.

[0065] <<Mass ratio of surfactant units to (meth)acrylic acid monomer units>> The mass ratio of surfactant units to (meth)acrylic acid monomer units in the copolymer (surfactant units / (meth)acrylic acid monomer units) is preferably 0.001 or higher, more preferably 0.010 or higher, even more preferably 0.020 or higher, preferably 0.100 or lower, more preferably 0.050 or lower, and even more preferably 0.030 or lower. If the mass ratio of surfactant units to (meth)acrylic acid ester monomer units in the copolymer is above the lower limit mentioned above, the wettability of the dielectric layer and the like can be effectively improved. On the other hand, if the mass ratio of surfactant units to (meth)acrylic acid ester monomer units in the copolymer is below the above upper limit, the blocking resistance of the dielectric layer and the like can be effectively improved.

[0066] <<Mass ratio of surfactant units to hydrophilic group-containing monomer units>> The mass ratio of surfactant units to hydrophilic group-containing monomer units in the copolymer (surfactant units / hydrophilic group-containing monomer units) is preferably 0.001 or higher, more preferably 0.005 or higher, preferably 0.500 or lower, and more preferably 0.200 or lower.

[0067] <<Properties of copolymers>> The copolymer is preferably water-soluble. If the copolymer is water-soluble, the foaming resistance of the slurry composition can be improved. In this specification, a copolymer is said to be "water-soluble" if, when 0.5 g of the copolymer is dissolved in 100 g of water at a temperature of 25°C, the insoluble content is less than 10% by mass.

[0068] The glass transition temperature of the copolymer is preferably 30°C or higher, more preferably 35°C or higher, even more preferably 40°C or higher, preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower. If the glass transition temperature of the copolymer is within the above range, the performance of the ceramic capacitor can be effectively improved.

[0069] The weight-average molecular weight of the copolymer is preferably 5,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more, preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. If the weight-average molecular weight of the copolymer is above the lower limit mentioned above, the blocking resistance of the dielectric layer and the like can be effectively improved. On the other hand, if the weight-average molecular weight of the copolymer is below the above upper limit, the wettability of the dielectric layer and the like can be effectively improved.

[0070] <<Method for preparing copolymers>> Copolymers 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. Here, the polymerization method for the copolymer is not limited, and any method such as solution polymerization (e.g., aqueous solution polymerization), slurry polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization may be used. Furthermore, addition polymerization such as ionic polymerization, radical polymerization, or living radical polymerization can be used as the polymerization reaction. Additives such as polymerization initiators, polymerization accelerators, emulsifiers, dispersants, and chain transfer agents (molecular weight adjusters) used in polymerization can be those that are commonly used, and the amounts used can also be those commonly used.

[0071] <Solvent> The solvent included in the binder composition of the present invention is not particularly limited, and either water or an organic solvent can be used. As organic solvents, for example, aqueous solvents such as methanol, ethanol, and lower alcohols such as isopropanol, and non-aqueous solvents such as methylbenzene (toluene) and xylene can be used. Alternatively, two or more solvents may be combined. Since this improves the foaming resistance of the slurry composition, the solvent is preferably water.

[0072] <Other ingredients> Other components that may be optionally included in the binder composition of the present invention include, for example, polymers other than the copolymer described above, the additives used when polymerizing the copolymer, and preservatives. Examples of preservatives include benzoisothiazolin-3-one.

[0073] The content of other components in the binder composition is, for example, 0.005 parts by mass or more, and may be 0.01 parts by mass or more, and may be 1 part by mass or less, and may be 0.1 parts by mass or less, when the copolymer in the binder composition is 100 parts by mass.

[0074] <Solid content concentration of binder composition> The solid content concentration of the binder composition is preferably 1% by mass or more, preferably 5% by mass or more, preferably 30% by mass or less, and more preferably 15% by mass or less.

[0075] <Method for preparing a binder composition> The binder composition of the present invention can be prepared by mixing the above-mentioned components by known methods. Specifically, the binder composition can be prepared by mixing the 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.

[0076] (Slurry composition for ceramic capacitors) The slurry composition for ceramic capacitors of the present invention comprises the binder composition of the present invention described above and a dielectric material, and may optionally contain a water-insoluble polymer. That is, the slurry composition of the present invention comprises a copolymer, a solvent, and a dielectric material, and may optionally contain a water-insoluble polymer. Here, the solvent contained in the slurry composition may be entirely derived from the binder composition, or it may be newly added to the slurry composition separately from the solvent derived from the binder composition. Furthermore, the slurry composition of the present invention may optionally contain components other than the copolymer, solvent, dielectric material, and water-insoluble polymer (hereinafter sometimes referred to as "other components"). Furthermore, the slurry composition of the present invention contains a binder composition that can impart excellent foaming resistance to the slurry composition and excellent wettability and blocking resistance to the dielectric layer, etc., and therefore provides excellent foaming resistance and excellent wettability and blocking resistance to the dielectric layer, etc.

[0077] <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.

[0078] Here, the dielectric material is preferably a perovskite structure because it can improve the performance of the 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.

[0079] 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 Sr y 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.

[0080] 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.

[0081] <Copolymer> Examples of copolymers included in the slurry composition of the present invention are those similar to those described in the "Copolymer" section of the "Binder Composition for Ceramic Capacitors" described above.

[0082] The copolymer content in the slurry composition is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, based on 100 parts by mass of dielectric material in the slurry composition. If the copolymer content in the slurry composition is above the lower limit mentioned above, the wettability of the dielectric layer and the like can be effectively improved. On the other hand, if the copolymer content in the slurry composition is below the above upper limit, the blocking resistance of the dielectric layer and the like can be effectively improved.

[0083] <Solvent> The solvent contained in the slurry composition of the present invention is the same as the solvent described in the "solvent" section of the "binder composition for ceramic capacitors" described above. In this case, the solvent is preferably water, as this improves the foaming resistance of the slurry composition.

[0084] <Water-insoluble polymer> The slurry composition of the present invention preferably further contains a water-insoluble polymer. Further inclusion of a water-insoluble polymer in the slurry composition can improve foaming resistance. Furthermore, it can improve the wettability of the dielectric layer and the like.

[0085] Here, the water-insoluble polymer is a component that can function as a binder. The water-insoluble polymer is not particularly limited, and any polymer can be used, for example, conjugated diene polymers, acrylic polymers, etc.

[0086] <<Conjugated Diene Polymer>> A conjugated diene polymer is a polymer containing conjugated diene monomer units. A conjugated diene polymer may optionally contain aromatic vinyl monomer units, hydrophilic group-containing monomer units, or cyano group-containing monomer units. Furthermore, a conjugated diene polymer may contain monomer units other than conjugated diene monomer units, aromatic vinyl monomer units, hydrophilic group-containing monomer units, and cyano group-containing monomer units (hereinafter sometimes referred to as "other monomer units B").

[0087] Examples of conjugated diene polymers include copolymers containing aromatic vinyl monomer units and conjugated diene monomer units, such as styrene-butadiene copolymer (SBR), butadiene rubber (BR), isoprene rubber, acrylic rubber (NBR) (a copolymer containing cyano group-containing monomer units and conjugated diene monomer units), and their hydrides.

[0088] [Conjugated diene monomer units] A conjugated diene monomer unit is a monomer unit that can be formed by conjugated diene monomers. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 2-chlor-1,3-butadiene, substituted linear conjugated pentadienes, and substituted and side-chain conjugated hexadienes. These may be used individually or in combination of two or more. Among these, 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene) are preferred as conjugated diene monomers, with 1,3-butadiene being more preferred.

[0089] The content of conjugated diene monomer units in a conjugated diene polymer is preferably 20% by mass or more, more preferably 25% by mass or more, preferably 60% by mass or less, and more preferably 55% by mass or less, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass.

[0090] [Aromatic vinyl monomer unit] Aromatic vinyl monomer units are monomer units that can be formed from aromatic vinyl monomers. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene, and divinylbenzene. These may be used individually or in combination of two or more. Among these, styrene is preferred as the aromatic vinyl monomer.

[0091] The content of aromatic vinyl monomer units in a conjugated diene polymer is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, preferably 70% by mass or less, and more preferably 65% ​​by mass or less, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass.

[0092] [Hydrophilic group-containing monomer unit] In conjugated diene polymers, hydrophilic group-containing monomer units are monomer units that can be formed by hydrophilic group-containing monomers. Examples of hydrophilic group-containing monomers include those similar to those described in the "Hydrophilic Group-Containing Monomer Units" section of the "Binder Composition for Ceramic Capacitors" mentioned above. These may be used individually or in combination of two or more types.

[0093] The content of hydrophilic group-containing monomer units in a conjugated diene polymer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, preferably 8% by mass or less, and more preferably 5% by mass or less, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass.

[0094] [Cyano group-containing monomer units] A cyano group-containing monomer unit is a monomer unit that can be formed from cyano group-containing monomers. Examples of cyano group-containing monomers include acrylonitrile and methacrylonitrile. These may be used individually or in combination of two or more types in any ratio.

[0095] In a conjugated diene polymer, the cyano group-containing monomer units are preferably 5% by mass or more, more preferably 10% by mass or more, preferably 25% by mass or less, and more preferably 20% by mass or less, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass.

[0096] [Other monomer units B] Other monomer units B are monomer units that can be formed by other monomer units B. Other monomer units B are not particularly limited as long as they are monomers copolymerizable with the monomers that can form the conjugated diene polymers described above. Other monomer units B include amide group-containing monomers such as acrylamide and methacrylamide; crosslinkable monomers (monomers that can be crosslinked) such as allyl glycidyl ether and allyl (meth)acrylate; olefins such as ethylene and propylene; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate; 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; N Examples include heterocyclic vinyl compounds such as vinylpyrrolidone, vinylpyridine, and vinylimidazole; amino group-containing monomers such as aminoethyl vinyl ether and dimethylaminoethyl vinyl ether; and alkyl (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. These other monomers B may be used individually or in combination of two or more types.

[0097] The content of other monomer units B in the conjugated diene polymer is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and even more preferably 0% by mass, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass. In other words, it is even more preferable that the conjugated diene polymer does not contain other monomer units B.

[0098] Furthermore, when alkyl (meth)acrylate monomers are used in the preparation of the conjugated diene polymer, the content of the alkyl (meth)acrylate monomer units is less than 50% by mass, when the total repeating units (total monomer units) contained in the conjugated diene polymer are taken as 100% by mass.

[0099] <<Acrylic polymer>> Acrylic polymers (ACLs) are polymers containing alkyl (meth)acrylate monomer units. Acrylic polymers may optionally contain hydrophilic group-containing monomer units and cyano group-containing monomer units. Furthermore, acrylic polymers may contain monomer units other than alkyl (meth)acrylate monomer units, hydrophilic group-containing monomer units, and cyano group-containing monomer units (hereinafter sometimes referred to as "other monomer units C"). It should be noted that acrylic polymers are typically polymers that contain 50% or more by mass of alkyl (meth)acrylate monomer units, when the total repeating units (total monomer units) contained in the acrylic polymer are taken as 100% by mass, and are different from the conjugated diene polymers described above.

[0100] [(meth)acrylate alkyl monomer unit] (Meth)acrylate alkyl ester monomer units are monomer units that can be formed by (meth)acrylate alkyl ester monomers. Examples of (meth)acrylate alkyl ester monomers include those similar to the (meth)acrylate alkyl ester monomers described in the "(meth)acrylate monomer unit" section of the "Binder composition for ceramic capacitors" mentioned above. These may be used individually or in combination of two or more types.

[0101] The content of alkyl (meth)acrylate monomer units in an acrylic polymer is usually 50% by mass or more, preferably 55% by mass or more, preferably 98% by mass or less, and more preferably 95% by mass or less, when the total repeating units (total monomer units) contained in the acrylic polymer are taken as 100% by mass.

[0102] [Hydrophilic group-containing monomer unit] In acrylic polymers, hydrophilic group-containing monomer units are monomer units that can be formed from hydrophilic group-containing monomers. Examples of hydrophilic group-containing monomers include those similar to those described in the "Hydrophilic Group-Containing Monomer Units" section of the "Binder Composition for Ceramic Capacitors" mentioned above. These may be used individually or in combination of two or more types.

[0103] The content of hydrophilic group-containing monomer units in an acrylic polymer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, preferably 8% by mass or less, and more preferably 5% by mass or less, when the total repeating units (total monomer units) contained in the acrylic polymer are taken as 100% by mass.

[0104] [Cyano group-containing monomer units] A cyano group-containing monomer unit is a monomer unit that can be formed from cyano group-containing monomers. Examples of cyano group-containing monomers that can be used in the preparation of acrylic polymers include those similar to those described in the "Cyano Group-Containing Monomer Units" section above. These may be used individually or in combination of two or more types in any ratio.

[0105] The content of cyano group-containing monomer units in an acrylic polymer is preferably 10% by mass or more, more preferably 15% by mass or more, preferably 45% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, when the total repeating units (total monomer units) contained in the acrylic polymer are taken as 100% by mass.

[0106] [Other monomer units C] Other monomer units C are monomer units that can be formed by other monomer units C. Other monomer units C are not particularly limited as long as they are monomers copolymerizable with the monomers that can form the acrylic polymer described above. Other monomer C examples include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, and divinylbenzene; amide group-containing monomers such as acrylamide and methacrylamide; crosslinkable monomers such as allyl glycidyl ether and allyl (meth)acrylate; olefins such as ethylene and propylene; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl esters such as vinyl acetate, vinyl propionate, and vinyl butyrate; 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; and amino group-containing monomers such as aminoethyl vinyl ether and dimethylaminoethyl vinyl ether. These may be used individually or in combination of two or more types.

[0107] The content of other monomer units C in the acrylic polymer is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and even more preferably 0% by mass, when the total repeating units (total monomer units and total structural units) contained in the acrylic polymer are taken as 100% by mass. In other words, it is even more preferable that the acrylic polymer does not contain other monomer units C.

[0108] <<Properties of water-insoluble polymers>> The water-insoluble polymer is preferably in particulate form in the slurry composition. Here, if the water-insoluble polymer is in particulate form in the slurry composition, it may exist in the dielectric layer or the like while maintaining its particle shape, or it may exist in any non-particle shape.

[0109] When the water-insoluble polymer is in particulate form, the volume-average particle diameter of the water-insoluble polymer is preferably 10 nm or more, more preferably 20 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 500 nm or less. In this specification, the volume-average particle size of water-insoluble polymers can be measured according to the method described in the examples.

[0110] The glass transition temperature of the water-insoluble polymer is preferably -60°C or higher, more preferably -50°C or higher, preferably -5°C or lower, and more preferably -10°C or lower.

[0111] <<Content of water-insoluble polymers>> The content of the water-insoluble polymer in the slurry composition of the present invention is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, when the dielectric material is 100 parts by mass.

[0112] <<Method for preparing water-insoluble polymers>> The polymerization method for water-insoluble polymers is not particularly limited, and any of the following methods may be used, for example, solution polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization. Furthermore, addition polymerization, such as ionic polymerization, radical polymerization, or living radical polymerization, can be used as the polymerization reaction. The polymerization solvents and additives such as emulsifiers, dispersants, polymerization initiators, and chain transfer agents used in polymerization can be general-purpose materials, and the amounts used can also be general-purpose amounts.

[0113] <Other ingredients> Other components that may be included in the slurry composition of the present invention are the same as those described in the "Other Components" section of the "Binder Composition for Ceramic Capacitors" described above.

[0114] The content of other components in the slurry composition is, for example, 0.005 parts by mass or more, and may be 0.01 parts by mass or more, and may be 1 part by mass or less, and may be 0.1 parts by mass or less, when the copolymer in the slurry composition is 100 parts by mass.

[0115] <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.

[0116] <Applications of slurry compositions> The slurry composition of the present invention is used in the manufacture of ceramic capacitors, and more specifically, it can be used to form a dielectric layer or electrode layer used in the manufacture of ceramic capacitors.

[0117] <<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. 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.

[0118] The content of dielectric material in the slurry composition for dielectric layers is preferably 40% by mass or more, more preferably 50% by mass or more, preferably 80% by mass or less, and more preferably 70% by mass or less, when the total components (including the solvent) in the slurry composition are considered to be 100% by mass.

[0119] <<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.

[0120] 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.

[0121] 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)

[0122] 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.

[0123] <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.

[0124] (Dielectric layer for ceramic capacitors) The dielectric layer for ceramic capacitors 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 dielectric layer is typically the slurry composition for dielectric layers described above. Here, the coating film (hereinafter sometimes referred to as the "dielectric film") provided by the dielectric layer of the present invention is made using the slurry composition of the present invention, which has excellent foam resistance and can impart excellent wettability and blocking resistance to the dielectric layer, and therefore has excellent density, wettability and blocking resistance.

[0125] 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 copolymer, and may optionally contain water-insoluble polymers, solvents, 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.

[0126] 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.

[0127] 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.

[0128] The method for producing the dielectric film is not particularly limited. For example, it can be produced by applying the dielectric layer slurry composition of the present invention onto a release substrate and drying the resulting film as desired.

[0129] 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.

[0130] 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.

[0131] The thickness of the release agent is not particularly limited, but it is usually between 20 μm and 100 μm.

[0132] The method for applying the slurry composition for dielectric layers onto a release substrate is not particularly limited, and known application methods include, for example, those using an applicator or various roll coaters such as gravure coaters and comma coaters (registered trademarks).

[0133] 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.

[0134] The dielectric layer of the present invention may have a coating film formed on the dielectric film that can form electrodes for a 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 electrode formation. Various printing methods such as screen printing, gravure printing, stamp printing, inkjet printing, and offset printing using patterns formed thereby; vacuum deposition for forming a metal vapor deposition film; and the like can be applied to form the coating film for electrode formation. Here, when forming an electrode-forming coating film 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 described above can also be used as the conductive paste.

[0135] (Electrode layer for ceramic capacitors) The electrode layer for ceramic capacitors 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 the electrode layer slurry composition described above. Here, the coating film (hereinafter sometimes referred to as "electrode film") of the electrode layer of the present invention is made using the slurry composition of the present invention, which has excellent foam resistance and can impart excellent wettability and blocking resistance to the electrode layer, and therefore has excellent density, wettability and blocking resistance.

[0136] 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 copolymer, and a conductive material, and may optionally contain water-insoluble polymers, solvents, and other components.

[0137] 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.

[0138] 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.

[0139] The method for producing the 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 above-mentioned electrode layer slurry composition onto the dielectric-forming coating film, and then drying the resulting film as desired. Here, the same release substrate as described in the section on "Dielectric layer for ceramic capacitors" 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 dielectric layer slurry composition described above can be used as the slurry.

[0140] The method for applying the slurry composition for the electrode layer onto the release substrate is not particularly limited, and known application methods include, for example, using an applicator or various roll coaters such as gravure coaters and comma coaters (registered trademarks).

[0141] The method for drying the electrode film is not particularly limited, and known drying methods using a hot air dryer can be used, for example. The drying conditions can be appropriately set according to the solvent content in the electrode film, the thickness of the 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.

[0142] (Ceramic capacitor) The ceramic capacitor of the present invention comprises a dielectric and an electrode, wherein the dielectric is made of the dielectric layer for ceramic capacitors of the present invention described above, or the electrode is made of the electrode layer for ceramic capacitors of the present invention described above. The ceramic capacitors described above offer excellent performance and productivity.

[0143] Examples of ceramic capacitors include multilayer ceramic capacitors comprising a dielectric, internal electrodes, and external electrodes, and single-layer ceramic capacitors comprising a dielectric and external electrodes. In the following description, the ceramic capacitor of the present invention will be explained using a multilayer ceramic capacitor as an example, but the ceramic capacitor of the present invention is not limited to a multilayer ceramic capacitor.

[0144] <Multilayer ceramic capacitor> Examples of the multilayer ceramic capacitors of the present invention include 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.

[0145] 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).

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] Sintering of degreased laminates typically occurs when the oxygen partial pressure is 10 -9 ~10 -12 The 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.

[0151] 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]

[0152] 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.

[0153] <Glass transition temperature> The copolymers (binder compositions) obtained in the examples and comparative examples were dried for 3 days in an environment of 50% humidity and 25°C to obtain a film with a thickness of 1.0 mm. This film was dried in a vacuum dryer at 60°C for 10 hours. Subsequently, the glass transition temperature (°C) of the dried film was measured using a DSC6220SII (differential scanning calorimetry analyzer, manufactured by Nanotechnology Inc.) in accordance with JIS K7121, under conditions of measurement temperature of -100°C to 180°C and heating rate of 5°C / min. Furthermore, the glass transition temperature (°C) of non-water-soluble polymers was measured using the same method as described above.

[0154] <Weight average molecular weight> The weight-average molecular weight of the copolymers obtained in the examples and comparative examples was measured by gel permeation chromatography (GPC). Specifically, first, the copolymer was added to approximately 5 mL of eluent so that its solid content concentration was approximately 0.5 g / L, and then slowly dissolved at room temperature. After visually confirming the dissolution of the copolymer, the mixture was gently filtered through a 0.45 μm filter to prepare the sample for measurement, and this sample was used for the measurement. Then, the weight-average molecular weight, converted to a standard substance, was calculated by creating a calibration curve using a standard substance. The measurement conditions were as follows. <<Measurement Conditions>> • Column: Manufactured by Showa Denko Corporation, product name Shodex OHpak (SB-G, SB-807HQ, SB-806MHQ) • Eluent: 0.1M Tris buffer (with 0.1M potassium chloride added) ·Flow rate: 0.5mL / min • Sample concentration: 0.05 g / L (solid content concentration) ·Injection volume: 200μL Column temperature: 40°C • Detector: Differential refractive index detector RI (manufactured by Tosoh Corporation, product name "RI-8020") • Standard material: Monodisperse pullulan (manufactured by Showa Denko Corporation)

[0155] <Volume-average particle size> The volume-average particle size of the water-insoluble polymer was measured by laser diffraction. Specifically, an aqueous dispersion containing the water-insoluble polymer (adjusted to a solid content concentration of 0.1% by mass) was used as the sample. The volume-average particle size was defined as the particle size D50 at which the cumulative volume calculated from the smallest diameter side in the particle size distribution (volume-based) measured using a laser diffraction particle size distribution analyzer (Beckman Coulter, product name "LS-230").

[0156] <Foam resistance> 100 g of the slurry compositions obtained in the examples and comparative examples were placed in a container with an inner diameter of 6 cm, and the slurry compositions were stirred at 2000 rpm for 5 minutes using a disperser equipped with a sawtooth disc turbine-type blade with a diameter of 3 cm. Afterward, the slurry compositions were placed in a pressurized case, and the internal pressure was increased to 0.1 MPa with nitrogen gas and held for 3 minutes. After removal, the number of bubbles with a diameter of 0.1 mm or more on the surface of the slurry composition was counted using a 20x magnifying glass, and the foaming resistance was evaluated according to the following criteria. A lower number of bubbles indicates better foaming resistance of the slurry composition. A: Less than 10 B: 10 or more but less than 20 C: 20 or more

[0157] <Wettability> The slurry compositions were prepared in the same manner as in each example and comparative example, except that no dielectric material was used in the slurry composition. These compositions were then used as evaluation slurry compositions to evaluate their wettability. Specifically, a conductive paste (solid content concentration 66%) was prepared by mixing 100 parts of Ni powder (average particle size: 0.3 μm) as a conductive material, 25 parts of barium titanate ("BT-01" manufactured by Sakai Chemical Industry Co., Ltd.) as a dielectric material, 2 parts of polyvinyl butyral (BL-2H manufactured by Sekisui Chemical Co., Ltd.) as a binder, and 65 parts of terpineol as an organic solvent. Next, the evaluation slurry composition was applied to a polyethylene terephthalate (PET) substrate to create a 5 μm thick coating film, which was then dried at 100°C for 10 minutes. Subsequently, 1 μL of conductive paste was dropped onto the resulting coating film, and the contact angle (°) formed between the coating film and the conductive paste droplet after 10 seconds was measured to evaluate the wettability according to the following criteria. A smaller contact angle indicates better wettability. A: Contact angle is 30° or less B: Contact angle greater than 30° and less than or equal to 40° C: Contact angle greater than 40°

[0158] <Blocking resistance> The slurry compositions obtained in the examples and comparative examples were applied to a release substrate and dried to prepare a 200m long release substrate with a dielectric layer, which was then wound up to obtain a roll-shaped release substrate with a dielectric layer. The obtained roll-shaped release substrate with a dielectric layer was left at 40°C for 30 days. After 30 days, the adhesion state of the dielectric layer to the back surface of the release substrate (roll peeling state) was visually confirmed, and the blocking resistance was evaluated according to the following criteria. A: The dielectric layer is not adhered to the back surface of the release substrate. B: The dielectric layer adheres to the back surface of the release substrate, but peels off. C: The dielectric layer adheres to the back surface of the release substrate and does not peel off.

[0159] (Example 1) <Preparation of Binder Composition (Aqueous Solution of Copolymer)> A monomer composition containing 35.0 parts methacrylic acid, 43.5 parts ethyl acrylate, 20.0 parts n-butyl acrylate, and 1.5 parts polyoxyalkylene alkenyl ether ammonium sulfate (manufactured by Kao Corporation, product name: Latemul PD-104), along with 150 parts ion-exchanged water and 1 part ammonium persulfate as a polymerization initiator, was placed in a 5 MPa pressure vessel equipped with a stirrer. After thorough stirring, the mixture was heated to 60°C to start polymerization. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling, and an aqueous sodium hydroxide solution was added to adjust the pH to 8. 0.08 parts benzoisothiazolin-3-one (Navigide P-40, manufactured by Katsuyama Chemical Co., Ltd.) was added as a preservative to obtain an aqueous solution (solid content concentration 10%) containing a water-soluble copolymer. Furthermore, the glass transition temperature and weight-average molecular weight were measured using the obtained binder composition, and its wettability was evaluated. The results are shown in Table 1.

[0160] <Preparation of an aqueous dispersion of a water-insoluble polymer> In a 5 MPa pressure vessel equipped with a stirrer, 74 parts of deionized water, 0.2 parts of sodium dodecyldiphenyl ether disulfonate, 1.0 part of ammonium persulfate as a polymerization initiator, and 9.7 parts of deionized water were added, and the mixture was heated to 70°C and stirred for 30 minutes. Next, in a separate 5 MPa pressure vessel equipped with a stirrer, 75.0 parts of 2-ethylhexyl acrylate as an alkyl (meth)acrylate monomer, 22.0 parts of acrylonitrile as a cyano group-containing monomer, 2.0 parts of itaconic acid as a hydrophilic group-containing monomer, 1.0 part of 2-hydroxyethyl acrylate as a hydrophilic group-containing monomer unit, 0.8 parts of sodium dodecyldiphenyl ether disulfonate as an emulsifier, and 74 parts of deionized water were added and stirred to prepare an emulsion. The prepared emulsion was sequentially added from polymerization tank B to polymerization tank A over approximately 200 minutes, then stirred for approximately 180 minutes. The reaction was terminated by cooling when the polymerization conversion rate reached 97% or higher. Subsequently, the pH was adjusted with a 4% NaOH aqueous solution, and unreacted monomers were removed by heated vacuum distillation to obtain an aqueous dispersion of acrylic polymer (solid content concentration 40%) as a water-insoluble polymer. The obtained aqueous dispersion had a pH of 8.0, and the acrylic polymer had a glass transition temperature of -20°C. The obtained acrylic polymer was particulate, and the volume-average particle size in the aqueous dispersion was 150 nm.

[0161] <Preparation of Slurry Composition> 100 parts by mass of barium titanate (BT-01, manufactured by Sakai Chemical Industry Co., Ltd.) with an average particle size (d50) of 0.1 μm as a dielectric material, 5 parts by mass of the copolymer prepared above (50 parts by mass as an aqueous solution), and 20 parts by mass of water as a solvent were mixed together with 100 parts by mass of zirconia beads (manufactured by Nikkatoh Co., Ltd.) with a particle size of 0.1 mm, using a bead mill (RMB-01, manufactured by AIMEX Co., Ltd.) and stirred at 500 rpm for 2 hours. Then, another 20 parts by mass of water was added and stirred at 500 rpm for 1 hour. The zirconia beads were filtered off to prepare a dispersion of barium titanate. 5 parts by mass of a water-insoluble polymer (12.5 parts by mass as an aqueous dispersion) were added to 190 parts by mass of this dispersion (100 parts by mass containing barium titanate), and these were then stirred at 1000 rpm for 3 minutes using a rotary-orbit mixer to prepare a slurry composition. Furthermore, the foaming resistance and blocking resistance of the obtained slurry composition were evaluated. The results are shown in Table 1.

[0162] <Fabrication of dielectric layers> The slurry composition obtained above was applied using a gravure coater to a release-treated film (Lintec Corporation, PET38AL-5) measuring 100 mm in width and 100 mm in length, such that the thickness of the green sheet after drying was approximately 1.0 μm. The film was then dried in an oven at 100°C for 5 minutes to obtain a release substrate with a dielectric layer (ceramic green sheet method).

[0163] (Example 2) In preparing the binder composition, the various operations and evaluations were carried out in the same manner as in Example 1, except that the amount of ethyl acrylate was changed from 43.5 parts to 44.8 parts and the amount of polyoxyalkylene alkenyl ether ammonium sulfate was changed from 1.5 parts to 0.2 parts. The results are shown in Table 1.

[0164] (Example 3) In preparing the binder composition, the various operations and evaluations were carried out in the same manner as in Example 1, except that the amount of ethyl acrylate was changed from 43.5 parts to 41.0 parts and the amount of polyoxyalkylene alkenyl ether ammonium sulfate was changed from 1.5 parts to 4.0 parts. The results are shown in Table 1.

[0165] (Example 4) In preparing the binder composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 1.5 parts of ammonium polyoxyalkylene alkenyl ether sulfate was replaced with 1.5 parts of sodium alkylallyl sulfosuccinate (manufactured by Sanyo Chemical Industries, Ltd., product name: Eleminor JS-20). The results are shown in Table 1.

[0166] (Example 5) In preparing the binder composition, the various operations and evaluations were carried out in the same manner as in Example 1, except that the amount of ethyl acrylate was changed from 43.5 parts to 63.5 parts and the amount of methacrylic acid was changed from 35.0 parts to 15.0 parts. The results are shown in Table 1.

[0167] (Example 6) In preparing the binder composition, the monomer composition was changed to 73.5 parts methacrylic acid, 25.0 parts n-butyl acrylate, and 1.5 parts polyoxyalkylene alkenyl ether ammonium sulfate. All other operations and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0168] (Example 7) In preparing the binder composition, various operations and evaluations were carried out in the same manner as in Example 1, except that 15.0 parts of methacrylic acid were replaced with 15.0 parts of 2-hydroxyethyl acrylate. The results are shown in Table 1.

[0169] (Example 8) In preparing the slurry composition, various operations and evaluations were carried out in the same manner as in Example 1, except that a water-insoluble polymer was not used. The results are shown in Table 1.

[0170] (Example 9) Except for the preparation of the slurry composition as described below, various operations and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0171] <Preparation of Slurry Composition> To the binder composition obtained using the same procedure as in Example 1, 100 parts by mass of ethanol was added, the mixture was allowed to coagulate, the precipitated polymer was filtered, and the copolymer was dried at 80°C for 24 hours to obtain a copolymer. Next, 100 parts by mass of barium titanate (BT-01, manufactured by Sakai Chemical Industry Co., Ltd.) with an average particle size (d50) of 0.1 μm as a dielectric material, 5 parts by mass of dried copolymer, and 15 parts by mass of toluene and 15 parts by mass of ethanol as solvents were mixed together with 100 parts by mass of zirconia beads (manufactured by Nikkatoh Co., Ltd.) with a particle size of 0.1 mm, using a bead mill (RMB-01, manufactured by AIMEX Co., Ltd.) and stirred at 500 rpm for 2 hours. After that, another 15 parts by mass of toluene and 15 parts by mass of ethanol were added and stirred at 500 rpm for 1 hour. The zirconia beads were filtered off to prepare the slurry composition.

[0172] (Comparative Example 1) In preparing the binder composition, the monomer composition was changed to 48.5 parts ethyl acrylate, 50.0 parts n-butyl acrylate, and 1.5 parts polyoxyalkylene alkenyl ether ammonium sulfate. All other operations and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0173] (Comparative Example 2) In preparing the binder composition, the monomer composition was changed to 35.0 parts methacrylic acid, 45.0 parts ethyl acrylate, and 20.0 parts n-butyl acrylate, and 1.5 parts sodium dodecylbenzenesulfonate was added as a nonpolymerizable surfactant. Otherwise, various operations and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0174] In Table 1 shown below, "EA" indicates the ethyl acrylate unit. "BA" indicates the n-butyl acrylate unit. "MAA" indicates the methacrylic acid unit. "β-HEA" indicates a 2-hydroxyethyl acrylate unit. "POAAE" represents the polyoxyalkylene alkenyl ether sulfate ammonium unit. "AASS" represents the alkylallyl sulfosuccinate sodium unit. "DBS" stands for sodium dodecylbenzene. "ACL" indicates acrylic polymer.

[0175] [Table 1]

[0176] As is clear from Table 1, the binder compositions of the examples can impart excellent foam resistance to the slurry composition, as well as excellent wettability and blocking resistance to the dielectric layer and the like. [Industrial applicability]

[0177] According to the present invention, it is possible to provide a binder composition for ceramic capacitors that can impart excellent foaming resistance to slurry compositions and excellent wettability and blocking resistance to dielectric layers and the like. Furthermore, according to the present invention, a slurry composition for ceramic capacitors containing the above-mentioned binder composition for ceramic capacitors can be provided. Furthermore, according to the present invention, it is possible to provide a dielectric layer for a ceramic capacitor and an electrode layer for a ceramic capacitor that include a coating film using the above-mentioned slurry composition for ceramic capacitors. Furthermore, according to the present invention, it is possible to provide a ceramic capacitor comprising a dielectric material using the above-mentioned dielectric layer for ceramic capacitors. Furthermore, according to the present invention, it is possible to provide a ceramic capacitor equipped with an electrode made using the above-mentioned electrode layer for ceramic capacitors. [Explanation of Symbols]

[0178] 10: Multilayer ceramic capacitor 11: Dielectrics 12: Internal electrode 13: External electrode

Claims

1. A copolymer containing (meth)acrylic acid ester monomer units, hydrophilic group-containing monomer units having at least one selected from the group consisting of carboxyl groups, hydroxyl groups, and phosphate groups, and surfactant units having sulfonic acid groups, Solvent and, A binder composition for ceramic capacitors, comprising: A binder composition for ceramic capacitors, wherein the proportion of the surfactant units in the copolymer is 0.1% by mass or more and 5.0% by mass or less, when the total repeating units in the copolymer are considered to be 100% by mass.

2. The binder composition for ceramic capacitors according to claim 1, wherein the proportion of the hydrophilic group-containing monomer units in the copolymer is 10.0% by mass or more and 80.0% by mass or less, when the total repeating units in the copolymer are considered to be 100% by mass.

3. The binder composition for ceramic capacitors according to claim 1, wherein the proportion of the (meth)acrylic acid ester monomer units in the copolymer is 15.0% by mass or more and 89.9% by mass or less, when the total repeating units in the copolymer are considered to be 100% by mass.

4. The binder composition for ceramic capacitors according to claim 1, wherein the glass transition temperature of the copolymer is 30°C or more and 100°C or less.

5. The binder composition for ceramic capacitors according to claim 1, wherein the weight-average molecular weight of the copolymer is 5,000 or more and 2,000,000 or less.

6. The binder composition for ceramic capacitors according to claim 1, wherein the solvent is water.

7. A slurry composition for a ceramic capacitor comprising the binder composition for a ceramic capacitor according to claim 1 and a dielectric material.

8. The slurry composition for ceramic capacitors according to claim 7, further comprising a water-insoluble polymer.

9. A dielectric layer for a ceramic capacitor, comprising a coating film using the ceramic capacitor slurry composition described in claim 7.

10. An electrode layer for a ceramic capacitor, comprising a coating film using the ceramic capacitor slurry composition described in claim 7.

11. A ceramic capacitor comprising a dielectric and an electrode, A ceramic capacitor wherein the dielectric is made of the dielectric layer for ceramic capacitors described in claim 9, or the electrode is made of the electrode layer for ceramic capacitors described in claim 10.

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