Resin composition for ceramic green sheets

Abstract

This invention provides a resin composition for ceramic green sheets, which exhibits excellent solvent solubility, reduces fine undissolved matter when dissolved in organic solvents, and enables the manufacture of ceramic capacitors with high reliability. This invention is a resin composition for ceramic green sheets containing polyvinyl acetal resin and compound A represented by the following formula (1), wherein the content of compound A is 2 ppm or more by weight. In formula (1), R1 and R3 independently represent a carboxyl group or its salt, and R2 represents a single bond or a divalent group that can be substituted by at least one substituent selected from the group consisting of hydroxyl, carboxyl, and their salts.

Description

[Technical Field]

[0001] This invention relates to a resin composition for ceramic green sheet. [Previous Technology]

[0002] In recent years, the miniaturization and multilayering of electronic components mounted on various electronic devices have been continuously developing, and multilayer electronic components such as multilayer circuit boards, multilayer coils, and multilayer ceramic capacitors are widely used. Among them, multilayer ceramic capacitors are usually manufactured through the following steps. First, adhesive resins such as polyvinyl butyral resin or poly(meth)acrylate resin are dissolved in an organic solvent. Plasticizers, dispersants, etc. are added to the resulting solution, and then ceramic raw material powder is added. The mixture is uniformly mixed using a mixing device such as a bead mill or ball mill. After defoaming, a ceramic slurry composition with a certain viscosity is obtained. The slurry composition is flowed onto the surface of a support such as a polyethylene terephthalate film or SUS plate after demolding treatment using a doctor blade or reverse roller coating machine. After removing volatile components such as solvents by heating or distillation, the slurry is peeled off from the support to obtain a ceramic green sheet. Subsequently, multiple sheets of conductive paste, applied by screen printing as internal electrodes, are alternately deposited on the obtained ceramic green sheet, and then heated and pressed together to form a multilayer. Afterward, a process called degreasing is performed to remove the adhesive resin components contained in the multilayer, and then external electrodes are sintered onto the end faces of the resulting sintered ceramic body to obtain a multilayer ceramic capacitor.

[0003] For example, Patent Document 1 describes a polyethylene acetal resin suitable as a ceramic or adhesive, which has a specified degree of polymerization, vinyl ester unit content, and degree of acetalization, and the molar ratio of the acetalized portion to the butyraldehyde-acetalized portion is within a specified range. Patent Document 2 describes a polyethylene acetal resin having a specified degree of polymerization, vinyl ester unit content, and degree of acetalization, and having specific constituent units. [Prior Art Documents] [Patent Documents]

[0004] Patent document: Japanese Patent Application Publication No. 2011-236304; Patent document: International Publication No. 2012 / 023517 [Summary of the Invention]

[0005] [The problem the invention aims to solve]

[0006] On the other hand, in recent years, with the increasing multifunctionality and miniaturization of electronic devices, there has been a demand for both large capacitance and small size in multilayer ceramic capacitors. To meet these demands, it is necessary to thoroughly remove even finer undissolved substances. However, even the polyvinyl acetal resin described in Patent Documents 1 and 2 suffers from the problem of insufficient removal of finer undissolved substances, requiring filtration and other methods to remove them, leading to decreased productivity. Furthermore, even the polyvinyl acetal resin described in Patent Documents 1 and 2 suffers from insufficient solubility in organic solvents.

[0007] The object of this invention is to provide a resin composition for ceramic green sheets that exhibits excellent solvent solubility, reduces fine undissolved matter when dissolved in organic solvents, and enables the manufacture of ceramic capacitors with excellent reliability. [Technical Means for Solving the Problem]

[0008] The present invention (1) is a resin composition for ceramic green sheets, which contains polyvinyl acetal resin and compound A represented by the following formula (1), wherein the content of compound A is 2 ppm or more on a weight basis, and in formula (1), R1 and R3 independently represent carboxyl groups or their salts, and R2 represents a single bond or a divalent group that can be substituted by at least one substituent selected from the group consisting of hydroxyl groups, carboxyl groups and their salts. The present invention (2) is a resin composition for ceramic green sheets as in the present invention (1), wherein, in formula (1), R2 is a linear alkyl group having 1 to 6 carbon atoms that can be substituted by at least one substituent selected from the group consisting of hydroxyl groups, carboxyl groups and their salts. The present invention (3) is a resin composition for ceramic green sheets as described in the present invention (1) or (2), wherein, in formula (1), R2 is a linear alkyl group having 1 to 3 carbon atoms, selected from the group consisting of salts of hydroxyl, carboxyl, etc. The present invention (4) is a resin composition for ceramic green sheets in any combination with any one of the present inventions (1) to (3), wherein X represented by the following formula (2) is 1.6 to 4.5. The present invention (5) is a resin composition for ceramic green sheets in any combination with any one of the present inventions (1) to (4), wherein compound A is at least one compound selected from the group consisting of salts of tartaric acid, malic acid, citric acid, etc. The present invention (6) is a resin composition for ceramic green sheets that is any combination of any one of the present inventions (1) to (5), wherein the solution obtained by dissolving 10% by weight of polyvinyl acetal resin in a mixed solution of ethanol / toluene (weight ratio 1:1) has a solution viscosity of 50 mPa·s or more at 20°C. The present invention (7) is a resin composition for ceramic green sheets that is any combination of any one of the present inventions (1) to (6), wherein the acetyl content of the polyvinyl acetal resin is 0.5% by weight or more and 20% by weight or less. The present invention (8) is a resin composition for ceramic green sheets that is any combination of any one of the present inventions (1) to (7), wherein the average degree of polymerization of the polyvinyl acetal resin is 500 or more. The present invention will be described in detail below.

[0009] The inventors conducted in-depth discussions and discovered that by adding a specified amount of compound A with a specific structure to polyvinyl acetal resin to prepare a resin composition, the solvent solubility is excellent, the fine undissolved matter is reduced when dissolved in organic solvents, and a ceramic capacitor with excellent reliability can be manufactured, thus completing the present invention.

[0010] The above-mentioned resin composition for ceramic green sheets contains polyvinyl acetal resin. The above-mentioned polyvinyl acetal resin generally has the following constituent units: a constituent unit having a hydroxyl group represented by the following formula (a-1); a constituent unit having an acetyl group represented by the following formula (a-2); and a constituent unit having an acetal group represented by the following formula (a-3).

[0011]

[0012] In the above formula (a-3), R 1a represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0013] The alkyl group having 1 to 20 carbon atoms mentioned above can be exemplified by: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, hexadecyl, hexadecyl, heptadeca, octadecyl, nonadecadecyl, eicosyl, etc. Among these, methyl, ethyl, and propyl are preferred.

[0014] Regarding the content of the constituent units containing hydroxyl groups represented by the above formula (a-1) in the above-mentioned polyvinyl acetal resin (hereinafter referred to as "hydroxyl content"), in terms of improving the strength and toughness of the resin, it is preferably 11% by weight or more, more preferably 13% by weight or more, and even more preferably 15% by weight or more. Furthermore, in terms of further improving solvent solubility, it is preferably 40% by weight or less, more preferably 35% by weight or less, and even more preferably 30% by weight or less. The above-mentioned hydroxyl content is preferably 11 to 40% by weight, more preferably 13 to 35% by weight, and even more preferably 15 to 30% by weight. The above-mentioned hydroxyl content can be determined, for example, by measuring the content (moles%) of each constituent unit using NMR and calculating the weight ratio.

[0015] Regarding the content of the acetyl group constituent unit represented by the above formula (a-2) in the above-mentioned polyethylene acetal resin (hereinafter referred to as "acetyl content"), in terms of suppressing high viscosity, it is preferably 0.5% by weight or more, more preferably 0.7% by weight or more, and even more preferably 0.8% by weight or more, and even more preferably 1% by weight or more. Furthermore, in terms of improving processability without excessively increasing the softness of the polyethylene acetal resin, it is preferably 30% by weight or less, more preferably 26% by weight or less, even more preferably 22% by weight or less, and even more preferably 20% by weight or less. The above-mentioned acetyl content is preferably 0.5 to 30% by weight, more preferably 0.7 to 26% by weight, even more preferably 0.8 to 22% by weight, and even more preferably 1 to 20% by weight. The above-mentioned acetyl content can be determined, for example, by measuring the content (moles%) of each constituent unit using NMR and calculating the weight ratio.

[0016] Regarding the content of the constituent units having acetal groups represented by the above formula (a-3) in the above-mentioned polyethylene acetal resin (hereinafter referred to as "acetal group content"), in terms of further improving solubility in solvents, it is preferably 45% by weight or more, more preferably 47% by weight or more, and even more preferably 49% by weight or more. Furthermore, in terms of improving the strength and toughness of the resin, it is preferably 86% by weight or less, more preferably 85% by weight or less, and even more preferably 83% by weight or less. The above-mentioned acetal group content is preferably 45 to 86% by weight, more preferably 47 to 85% by weight, and even more preferably 49 to 83% by weight. The above-mentioned acetal group content can be determined, for example, by measuring the content (moles%) of each constituent unit using NMR and calculating the weight ratio. Furthermore, regarding the calculation method for the amount of acetal groups, since the acetal group of polyethylene acetal resin is obtained by acetalizing two hydroxyl groups of polyvinyl alcohol, the method of converting the constituent unit with acetal group into two constituent units with hydroxyl groups can be used for counting.

[0017] In addition to the constituent units (a-1), (a-2), and (a-3), the above-mentioned polyethylene acetal resin may also have other constituent units. As other constituent units, for example, it may have: constituent units having functional groups such as carboxyl groups, sulfonic acid groups, epoxy alkyl groups, amide groups, or ethyl groups, or ethyl units.

[0018] As the above-mentioned constituent units having a carboxyl group, examples include: the constituent unit represented by formula (b-1) below, the constituent unit represented by formula (b-2) below, and the constituent unit represented by formula (b-3) below.

[0019]

[0020] In the above formula (b-1), R1b and R2b independently represent alkyl groups with 0 to 10 carbon atoms, and X1b and X2b independently represent hydrogen atoms, metal atoms or methyl groups.

[0021] In the above formula (b-1), the preferred lower limit for the number of carbon atoms in the alkyl groups represented by R1b ​​and R2b is 0, the preferred upper limit is 5, the more preferred lower limit is 1, and the more preferred upper limit is 3. R1b and R2b may be the same or different, but are preferably different. Furthermore, it is preferred that at least one of them is a single bond.

[0022] Examples of the above-mentioned alkyl groups having 0 to 10 carbon atoms include: straight-chain alkyl groups such as single bond, methylene, ethyl alkyl group, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, and decamethylene; branched alkyl groups such as methylmethylene, methyl ethyl alkyl group, 1-methyl pentyl alkyl group, and 1,4-dimethyl butyl alkyl group; and cyclic alkyl groups such as cyclopropyl alkyl group, cyclobutyl alkyl group, and cyclohexyl alkyl group. Among these, straight-chain alkyl groups such as single bond, methylene, ethyl alkyl group, n-propyl alkyl group, and n-butyl alkyl group are preferred, and single bond, methylene, and ethyl alkyl group are even more preferred.

[0023] In the above formula (b-1), when at least one of X1b and X2b is a metal atom, such metal atoms include, for example, sodium atoms, lithium atoms, potassium atoms, etc. Among them, sodium atoms are preferred.

[0024] The constituent unit represented by formula (b-1) above is preferably derived from an α-dicarboxylic acid monomer. Examples of α-dicarboxylic acid monomers include: methylene malonic acid, itconic acid, 2-methylene glutaric acid, 2-methylene adipic acid, 2-methylene sebacic acid, and other dicarboxylic acids or their metal salts or methyl esters that have unsaturated double bonds capable of free radical polymerization. Among these, itconic acid or its metal salt or its methyl ester is preferred. Furthermore, in this specification, an α-dicarboxylic acid monomer refers to a monomer having two carboxyl groups on the α-carbon.

[0025] In the above formula (b-2), R3b, R4b and R5b each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R6b represents an alkyl group having 0 to 10 carbon atoms, and X3b represents a hydrogen atom, a metal atom or a methyl group.

[0026] In the above formula (b-2), the preferred lower limit for the number of carbon atoms of the alkyl groups represented by R3b, R4b and R5b is 1, the preferred upper limit is 5, and the more preferred upper limit is 3. The preferred number of carbon atoms is 1 to 5, and the more preferred number is 1 to 3.

[0027] R3b, R4b, and R5b may be the same or different, but are preferably the same. Also, R3b, R4b, and R5b are preferably hydrogen atoms.

[0028] Examples of alkyl groups having 1 to 10 carbon atoms include: straight-chain alkyl groups such as methyl, ethyl, propyl, n-butyl, n-pentyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; branched-chain alkyl groups such as isopropyl, isobutyl, dibutyl, tributyl, isopentyl, 2,2-dimethylpropyl, 1,1,3,3-tetramethylbutyl, and 2-ethylhexyl; and cycloalkyl groups such as cyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, and cyclohexyl. Among these, straight-chain alkyl groups such as methyl, ethyl, propyl, and n-butyl are preferred, and methyl and ethyl are even more preferred.

[0029] As R 6b in the above formula (b-2), examples of the same as R 1b and R 2b in the above formula (b-1) can be listed, wherein it is preferably a straight-chain alkyl group such as a single bond, methylene, ethyl, trimethylene, or tetramethylene, more preferably a single bond, methylene, or ethyl, and even more preferably a single bond.

[0030] In the above formula (b-2), when X 3b is a metal atom, the metal atom can be, for example, a sodium atom, a lithium atom, a potassium atom, etc. Among them, a sodium atom is preferred.

[0031] The constituent unit represented by formula (b-2) above is preferably derived from a monocarboxyl monomer. Examples of monocarboxyl monomers include: acrylic acid, butenoic acid, methacrylic acid, oleic acid, and other monocarboxylic acids with free radical polymerizability and unsaturated double bonds, or their metal salts or methyl esters. Among these, butenoic acid, its metal salt, or its methyl ester is preferred.

[0032] In the above formula (b-3), R7b and R9b independently represent hydrogen atoms or alkyl groups having 1 to 10 carbon atoms, R8b and R10b represent alkyl groups having 0 to 10 carbon atoms, and X4b and X5b represent hydrogen atoms, metal atoms or methyl groups.

[0033] In the above formula (b-3), the preferred lower limit for the number of carbon atoms of the alkyl groups represented by R 7b and R 9b is 1, the preferred upper limit is 5, and the more preferred upper limit is 3. The preferred number of carbon atoms is 1 to 5, and the more preferred number is 1 to 3.

[0034] The above R 7b and R 9b may be the same or different, but it is preferred that they are the same.

[0035] As for R7b and R9b in the above formula (b-3), examples of the same as those of R3b, R4b and R5b in the above formula (b-2) can be listed, wherein hydrogen atoms are preferred.

[0036] As for R8b and R10b in the above formula (b-3), examples of the same as those of R1b and R2b in the above formula (b-1) can be listed, wherein it is more preferably a straight-chain alkyl group such as a single bond, methylene, ethyl, trimethylene, or tetramethylene, more preferably a single bond, methylene, or ethyl, and even more preferably a single bond.

[0037] In the above formula (b-3), when X4b and X5b are metal atoms, such as sodium atoms, lithium atoms, potassium atoms, etc., can be used as the metal atoms. Among them, sodium atoms are preferred.

[0038] As the above-mentioned constituent unit having a sulfonic acid group, the constituent unit represented by the following formula (c) can be listed.

[0039]

[0040] In formula (c), R 1c represents an alkyl group with 0 to 10 carbon atoms, and X 1c represents a hydrogen atom, a metal atom, or a methyl group.

[0041] As R1c in the above formula (c), examples of the same as R1b and R2b in the above formula (b-1) can be listed, wherein it is preferably a straight-chain alkyl group such as a single bond, methylene, ethyl, trimethylene, or tetramethylene, more preferably a single bond, methylene, or ethyl, and even more preferably a single bond or methylene.

[0042] In the above formula (c), when X 1c is a metal atom, the metal atom can be, for example, sodium atom, lithium atom, potassium atom, etc. Among them, sodium atom is preferred.

[0043] As the above-mentioned constituent unit having an epoxy alkyl group, the constituent unit represented by the following formula (d) can be listed.

[0044]

[0045] In formula (d), R d1 represents an epoxy alkyl group having 2 to 6 carbon atoms.

[0046] Examples of epoxy alkyl groups having 2 to 6 carbon atoms include: ethylene oxide, propylene oxide, butyl oxide, pentyl oxide, and hexyl oxide. Examples of constituent units having epoxy alkyl groups as represented by formula (d) above include: polyethylene glycol and the like having a plurality of ethylene oxide constituent units, constituent units having only ethylene oxide, and constituent units having different epoxy alkyl groups.

[0047] The aforementioned constituent unit having an alkyl oxide is preferably a constituent unit having an ethylene oxide as represented by the following formula (e-1), or a constituent unit having an ethylene oxide and an propylene oxide as represented by the following formula (e-2).

[0048]

[0049] In the above formula (e-1), Re1 and Re2 represent linkage bases or single bonds with at least one of the groups composed of C and O, and n1 represents an integer.

[0050] The aforementioned Re1 has at least one linking group or single bond selected from the group consisting of C and O. The aforementioned Re1 is preferably an alkyl group, carbonyl group, or oxygen atom having 1 to 10 carbon atoms. Examples of the aforementioned Re1 include: methylene, ethyl, carbonyl, ether, allyl ether, amide, etc. The aforementioned Re2 has at least one linking group or single bond selected from the group consisting of C and O. The aforementioned Re2 is preferably an alkyl group, carbonyl group, or oxygen atom having 1 to 10 carbon atoms. Examples of the aforementioned Re2 include: methylene, ethyl, propyl, carbonyl, ether, etc. Furthermore, the number of repetitions of the epoxide, i.e., the integer n1, is not particularly limited, but is preferably 2 to 70, more preferably 5 to 50.

[0051] In the above formula (e-2), Re3, Re4 and Re5 represent linkage bases or single bonds with at least one of the groups composed of C and O, and n2 and n3 represent integers.

[0052] Examples of Re3, Re4, and Re5 mentioned above are the same as those of Re1 and Re2 in formula (e-1) above. Furthermore, the number of repetitions of the epoxide, i.e., the integers n2 and n3, is not particularly limited, but n2 is preferably 1 to 40, more preferably 20 to 30. Also, n3 is preferably 1 to 40, more preferably 20 to 30.

[0053] As the above-mentioned constituent unit having a amide group, the constituent unit represented by the following formula (f) can be listed.

[0054]

[0055] In the above formula (f), R 1f represents an alkyl group having 1 to 10 carbon atoms.

[0056] As R1f in the above formula (f), examples of the same as R3b, R4b and R5b in the above formula (b-2) can be listed, wherein it is preferably a straight-chain alkyl group such as hydrogen atom, methyl, ethyl, propyl, n-butyl, etc., and more preferably hydrogen atom, methyl or ethyl.

[0057] The content of the functionalized constituent units in the above-mentioned polyvinyl acetal resin is preferably 0% by weight or more, more preferably 0.1% by weight or more, further preferably 0.5% by weight or more, and preferably 5% by weight or less, more preferably 3% by weight or less. The content of the functionalized constituent units is preferably 0 to 5% by weight, more preferably 0.1 to 3% by weight, and further preferably 0.5 to 3% by weight. The content of the functionalized constituent units can be determined, for example, by measuring the content (moles%) of each constituent unit using NMR and calculating the weight ratio.

[0058] As the above-mentioned ethyl unit, the constituent unit represented by the following formula (g) can be listed.

[0059]

[0060] In the above-mentioned polyvinyl acetal resin, the content of the above-mentioned ethylated unit (hereinafter also referred to as "ethylated content") is preferably 1% by weight or more, more preferably 3% by weight or more, and more preferably 20% by weight or less, more preferably 10% by weight or less. The above-mentioned ethylated content is preferably 1 to 20% by weight, more preferably 3 to 10% by weight. The above-mentioned ethylated content can be determined, for example, by measuring the content (moles%) of each constituent unit using NMR and calculating the weight ratio.

[0061] Furthermore, in this specification, the ethyl content of the polyethylene acetal resin refers to the apparent ethyl content of the polyethylene acetal resin as a whole. That is, for example, when the polyethylene acetal resin contains multiple resins with different ethyl contents, the ethyl content of the polyethylene acetal resin is obtained by adding the values ​​obtained by multiplying the ethyl content of each resin by the content ratio of that resin.

[0062] In the above-mentioned polyvinyl acetal resin, the ratio of ethylened ethyl content to hydroxyl content (ethylened ethyl content / hydroxyl content) is preferably 0.01 or more, and preferably 1.0 or less. The above ratio is preferably 0.01 to 1.0.

[0063] Regarding the average degree of polymerization of the aforementioned polyvinyl acetal resin, in terms of improving mechanical strength, it is preferably 200 or higher, more preferably 300 or higher. Furthermore, from the viewpoint of solvent solubility or viscosity, it is preferably 500 or higher, more preferably 10,000 or lower, and even more preferably 5,500 or lower. The aforementioned average degree of polymerization is preferably 200 to 10,000, more preferably 300 to 5,500, and even more preferably 500 to 5,500. Moreover, the aforementioned average degree of polymerization is the same as the average degree of polymerization of the raw material polyvinyl alcohol resin. The average degree of polymerization of the raw material polyvinyl alcohol resin can be determined according to JIS K 6726.

[0064] The solution obtained by dissolving the above-mentioned polyethylene acetal resin at a concentration of 10% by weight in an ethanol / toluene mixed solution (weight ratio 1:1) preferably has a viscosity of 50 mPa·s or more, more preferably 70 mPa·s or more, and even more preferably 100 mPa·s or more, and preferably 20,000 mPa·s or less, more preferably 18,000 mPa·s or less, and even more preferably 16,000 mPa·s or less. The above viscosity is preferably 50 to 20,000 mPa·s, more preferably 70 to 18,000 mPa·s, and even more preferably 100 to 16,000 mPa·s. By setting it within the above range, uniform solvent solubility is ensured, and mechanical strength can be improved. The above viscosity can be measured, for example, using a type B viscometer at a solution temperature of 20°C.

[0065] The shape of the above-mentioned polyethylene acetal resin is not particularly limited, but it is preferably in particulate form. Furthermore, when the above-mentioned polyethylene acetal resin is in particulate form, in order to further improve its solubility in organic solvents, the porosity is preferably 20% or more, more preferably 25% or more, and even more preferably 30% or more, and preferably 80% or less, even more preferably 70% or less, and even more preferably 60% or less. The above-mentioned porosity is preferably 20-80%, more preferably 25-70%, and even more preferably 30-60%. The above-mentioned porosity refers to the volume of voids with a pore radius of 0.0038-7.5 μm occupying the volume of the resin particles. The above-mentioned porosity can be measured, for example, using a porosimeter (Thermo Pascal 14B, manufactured by Thermo Fisher Scientific) using mercury porosimetry. The porosity can be adjusted by adjusting the concentration of polyvinyl alcohol resin or the stirring conditions in the acetalization step; or by adjusting the temperature in the neutralization step of the obtained resin particles. For example, during the acetalization reaction, the lower the concentration of polyvinyl alcohol relative to the amount of pure water, the higher the porosity of the obtained resin particles.

[0066] When the aforementioned polyvinyl acetal resin is in particle form, in order to further improve its solubility in organic solvents, the specific surface area is preferably 10 m² / g or more, more preferably 12 m² / g or more, and even more preferably 15 m² / g or more, and preferably 30 m² / g or less, even more preferably 25 m² / g or less, and even more preferably 20 m² / g or less. The aforementioned specific surface area is preferably 10 to 30 m² / g, more preferably 12 to 25 m² / g, and even more preferably 15 to 20 m² / g. Furthermore, in this specification, the aforementioned specific surface area refers to the surface area per unit weight, which can be measured, for example, using a porosimeter (Thermo Pascal 14B, manufactured by Thermo Fisher Scientific) by mercury porosimetry.

[0067] When the above-mentioned polyvinyl acetal resin is in particle form, in order to further improve its solubility in organic solvents, the D50 particle size is preferably 30 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, and preferably 800 μm or less, even more preferably 600 μm or less, and even more preferably 500 μm or less. The above-mentioned D50 particle size is preferably 30 to 800 μm, more preferably 50 to 600 μm, and even more preferably 100 to 500 μm. Furthermore, the D90 particle size is preferably 30 μm or more, more preferably 50 μm or more, even more preferably 100 μm or more, and even more preferably 1000 μm or less, even more preferably 900 μm or less, and even more preferably 800 μm or less. The D90 particle size is preferably 30–1000 μm, more preferably 50–900 μm, and even more preferably 100–800 μm. Furthermore, the D10 particle size is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, and preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 200 μm or less. The D10 particle size is preferably 10–400 μm, more preferably 20–300 μm, and even more preferably 30–200 μm. Furthermore, the aforementioned "D90 particle size (D90)" refers to the particle size at which the cumulative frequency of distribution from the smallest particle side reaches 90% in particle size distribution measurement; "D50 particle size (D50)" refers to the particle size at which the cumulative frequency of distribution in the same manner reaches 50%; and "D10 particle size (D10)" refers to the particle size at which the cumulative frequency of distribution in the same manner reaches 10%. The aforementioned D90, D50, and D10 can be measured, for example, using a laser diffraction particle size distribution measuring device (Mastersizer 3000, manufactured by Malvern Panalytical). Methods for controlling particle size include adjusting the concentration or stirring conditions of the polyvinyl alcohol resin in the acetalization step; or adjusting the temperature and concentration in the neutralization step of the obtained resin particles. For example, the higher the concentration of polyvinyl alcohol relative to the volume of pure water during the acetalization reaction, the larger the D50 of the obtained resin particles.

[0068] When the above-mentioned polyvinyl acetal resin is in particle form, the particle size distribution ε is preferably 0.01 or more, more preferably 0.50 or more, and preferably 4.00 or less, more preferably 3.00 or less. The above-mentioned particle size distribution ε is preferably 0.01 to 4.00, more preferably 0.50 to 3.00. Furthermore, the above-mentioned particle size distribution ε is calculated based on [(D90 - D10) / D50].

[0069] The content of polyvinyl acetal resin in the above-mentioned resin composition for ceramic green sheets is preferably 94% by weight or more, more preferably 95% by weight or more, and even more preferably 96% by weight or more, and preferably 99.99% by weight or less, more preferably 99.5% by weight or less, and even more preferably 99% by weight or less. The above content is preferably 94 to 99.99% by weight, more preferably 95 to 99.5% by weight, and even more preferably 96 to 99% by weight.

[0070] The above-mentioned polyethylene acetal resin can usually be manufactured by acetalizing polyvinyl alcohol resin.

[0071] As the aforementioned polyvinyl alcohol resin, conventionally known polyvinyl alcohol resins can be used, such as resins manufactured by saponifying polyvinyl acetate-based resins using alkali, acid, ammonia, etc. The aforementioned polyvinyl alcohol resin can be completely saponified, but if at least one unit with a dihydroxyl group relative to the meso and racemo positions exists at at least one position in the main chain, complete saponification is not required, and it can be a partially saponified polyvinyl alcohol resin. Furthermore, as the aforementioned polyvinyl alcohol resin, copolymers of monomers that can be copolymerized with ethylene alcohol, such as ethylene-vinyl alcohol copolymer resins and partially saponified ethylene-vinyl alcohol copolymer resins, can also be used. Examples of the aforementioned polyvinyl acetate-based resins include ethylene-vinyl acetate copolymers.

[0072] The degree of saponification of the above-mentioned polyvinyl alcohol resin is preferably 80 mol% or more, more preferably 88 mol% or more, and preferably 99.4 mol% or less, more preferably 99 mol% or less. The above-mentioned degree of saponification is preferably 80 to 99.4 mol%, more preferably 88 to 99 mol%.

[0073] The above-mentioned acetalization can be carried out using known methods, preferably in an aqueous solvent, a mixed solvent of water and an organic solvent miscible with water, or an organic solvent. For example, an alcohol-based organic solvent can be used as the organic solvent miscible with water. Examples of such organic solvents include: alcohol-based organic solvents, aromatic organic solvents, aliphatic ester solvents, ketone solvents, lower alkane solvents, ether solvents, acetylamine solvents, and amine solvents. Examples of such alcohol-based organic solvents include: methanol, ethanol, n-propanol, isopropanol, n-butanol, and tributanol. Examples of such aromatic organic solvents include: xylene, toluene, ethylbenzene, and methyl benzoate. Examples of such aliphatic ester solvents include: methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl acetoacetate, and ethyl acetoacetate. Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, benzophenone, and acetophenone. Examples of lower alkane solvents include hexane, pentane, octane, cyclohexane, and decane. Examples of ether solvents include diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol diethyl ether. Examples of acetylamine solvents include N,N-dimethylformamide, N,N-dimethylacetylamine, N-methylpyrrolidone, and acetaniline. Examples of amine solvents include ammonia, trimethylamine, triethylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, aniline, N-methylaniline, N,N-dimethylaniline, and pyridine. These solvents can be used individually or in mixtures of two or more. From the perspective of resin solubility and ease of purification, ethanol, n-propanol, isopropanol, and tetrahydrofuran are particularly preferred.

[0074] The above-mentioned acetalization is preferably carried out in the presence of an acid catalyst. The acid catalyst is not particularly limited, and examples include: mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; carboxylic acids such as formic acid, acetic acid, and propionic acid; and sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. These acid catalysts can be used alone or in combination with two or more compounds. Hydrochloric acid, nitric acid, and sulfuric acid are preferred, with nitric acid being particularly preferred.

[0075] The above-mentioned acetalization is preferably carried out in the presence of the above-mentioned compound A. Specifically, the compound described later can be used as compound A. By carrying out acetalization in the presence of the above-mentioned compound A, a uniform acetalization reaction can be achieved.

[0076] Relative to 100 parts by weight of polyvinyl alcohol resin, the amount of compound A added is preferably 0.8 parts by weight or more, more preferably 1.2 parts by weight or more, and even more preferably 1.6 parts by weight or more, and preferably 100 parts by weight or less, more preferably 50 parts by weight or less, and even more preferably 30 parts by weight or less. The above-mentioned amount added is preferably 0.8 to 100 parts by weight, more preferably 1.2 to 50 parts by weight, and even more preferably 1.6 to 30 parts by weight.

[0077] Aldehydes used in the above-described acetalization can include chain-like aliphatic groups, cyclic aliphatic groups, or aromatic groups having 1 to 10 carbon atoms. Aldehydes known in the art can be used as such. There are no particular limitations on the aldehydes used in the above-described acetalization reaction; for example, aliphatic aldehydes and aromatic aldehydes can be included. Examples of aliphatic aldehydes include: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-pentanaldehyde, n-hexanaldehyde, 2-ethylbutanaldehyde, 2-ethylhexanaldehyde, n-heptanaldehyde, n-octanaldehyde, n-nonanaldehyde, n-decanaldehyde, and pentanaldehyde. Examples of aromatic aldehydes include: benzaldehyde, cinnamaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, and β-phenylpropanaldehyde. One of these aldehydes can be used alone, or two or more can be used in combination. Among aldehydes, formaldehyde, acetaldehyde, butyraldehyde, 2-ethylhexanal, and n-nonanal are preferred as they exhibit excellent acetalization reactivity, provide sufficient internal plasticization to the resulting resin, and impart good flexibility. Furthermore, formaldehyde, acetaldehyde, and butyraldehyde are even more preferred in terms of obtaining adhesive compositions with particularly excellent impact resistance and adhesion to metals.

[0078] The amount of aldehyde added can be appropriately set according to the amount of acetal group in the target polyethylene acetal resin.

[0079] The above-mentioned resin composition for ceramic green sheets contains compound A represented by the following formula (1). By containing the above-mentioned compound A, it is possible to reduce fine undissolved matter when dissolved in an organic solvent.

[0080]

[0081] In formula (1), R1 and R3 independently represent a carboxyl group or its salt, and R2 represents a single bond or a divalent group that can be substituted by at least one substituent selected from the group consisting of salts of hydroxyl groups, carboxyl groups, etc. Examples of such salts include lithium salts, sodium salts, and potassium salts. R1 and R3 may be the same or different, but are preferably the same. Furthermore, R2 is preferably a divalent group having at least one substituent selected from the group consisting of salts of hydroxyl groups, carboxyl groups, etc.

[0082] Examples of the aforementioned divalent groups include divalent hydrocarbon groups. Examples of such hydrocarbon groups include: straight-chain alkyl groups having 1 to 6 carbon atoms, branched alkyl groups having 3 to 6 carbon atoms, straight-chain alkenyl groups having 2 to 6 carbon atoms, branched alkenyl groups having 3 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, and aromatic hydrocarbon groups having 6 carbon atoms. Among these, straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 4 carbon atoms are preferred, and straight-chain alkyl groups having 1 to 3 carbon atoms are even more preferred.

[0083] As linear alkyl groups having 1 to 6 carbon atoms, examples include: methylene, ethyl alkyl, trimethylene, tetramethylene, pentamethylene, hexamethylene, etc.

[0084] As branched alkyl groups having 3 to 6 carbon atoms, examples include: 1-methylethyl, 2-methyltrimethylene, 2-methyltetramethylene, 2-methylpentamethylene, etc.

[0085] As linear alkenyl groups with 2 to 6 carbon atoms, examples include: vinyl, propenyl, butenyl, hexenyl, etc.

[0086] As a branched enylene group with 3 to 6 carbon atoms, examples include: enylisopropenyl, 1-ethylenylene, 2-methylenylpropenyl, 2,2-dimethylenylene, 3-methyl-2-enylene, 3-ethyl-2-enylene, etc.

[0087] As cycloalkyl groups having 3 to 6 carbon atoms, examples include: cyclopentyl, cyclohexyl, etc.

[0088] Examples of cyclopentenyl groups with 3 to 6 carbon atoms include: cyclopentenyl, 2,4-cyclopentadienyl, cyclohexenyl, etc.

[0089] As an aromatic hydrocarbon group with 6 carbon atoms, examples include 1,2-epenylphenyl, etc.

[0090] As R2, more specifically, it is preferably hydroxyethyl, 1,2-dihydroxyethyl, 2-hydroxy-2-carboxytrimethylene, hydroxymethylene, trimethylene, methylene, and more preferably hydroxyethyl, 1,2-dihydroxyethyl, and 2-hydroxy-2-carboxytrimethylene.

[0091] The molecular weight of compound A is preferably 90 or more, more preferably 130 or more, even more preferably 150 or more, and preferably 10,000 or less, even more preferably 1,000 or less, even more preferably 500 or less. The molecular weight is preferably 90 to 10,000, more preferably 130 to 1,000, even more preferably 150 to 500.

[0092] Specifically, the compound A mentioned above can include: aliphatic hydroxy acids such as citric acid, malic acid, tartaric acid, hydroxymalonic acid, isocitric acid, and methyl dihydroxyvalerate; and aliphatic dicarboxylic acids such as oxalic acid, malonic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, and octanoic acid. Among these, citric acid, malic acid, tartaric acid, hydroxymalonic acid, glutaric acid, and malonic acid are preferred, and citric acid, malic acid, and tartaric acid are even more preferred.

[0093] Regarding the improvement of solubility in organic solvents, the content of compound A in the aforementioned resin composition for ceramic green sheets is 2 ppm or more by weight. Furthermore, the content of compound A by weight is preferably 5 ppm or more, more preferably 10 ppm or more, more preferably 29,000 ppm or less, more preferably 28,000 ppm or less, and even more preferably 26,000 ppm or less. The aforementioned content is preferably 2 to 29,000 ppm, more preferably 5 to 28,000 ppm, and even more preferably 10 to 26,000 ppm. The content of compound A can be determined, for example, by ion chromatography.

[0094] Relative to 100 parts by weight of the aforementioned polyvinyl acetal resin, the content of compound A in the aforementioned resin composition for ceramic green sheets is preferably 2 ppm or more, more preferably 5 ppm or more, and even more preferably 10 ppm or more, and preferably 29,000 ppm or less, more preferably 28,000 ppm or less, and even more preferably 26,000 ppm or less. The aforementioned content is preferably 2 to 29,000 ppm, more preferably 5 to 28,000 ppm, and even more preferably 10 to 26,000 ppm.

[0095] Regarding the resin composition for ceramic green sheets described above, X represented by the following formula (2) is preferably 1.6 or more, and preferably 4.5 or less. By setting it within the above range, uniform solvent solubility is ensured, and mechanical strength can be improved. X is more preferably 1.7 or more, and more preferably 4.4 or less. X is preferably 1.6 to 4.5, and more preferably 1.7 to 4.4.

[0096]

[0097] The resin composition for ceramic green sheets described above may also contain antioxidants, ultraviolet absorbers, surfactants, defoamers and other components, as long as it does not hinder the effect of the present invention.

[0098] As a method for manufacturing the above-mentioned resin composition for ceramic green chips, for example, a resin composition for ceramic green chips containing polyvinyl acetal resin and compound A can be prepared by acetalizing polyvinyl alcohol resin with an aldehyde in the presence of the above-mentioned compound A. Alternatively, for example, a polyvinyl acetal resin can be obtained by acetalizing polyvinyl alcohol resin with an aldehyde, and the above-mentioned compound A and other additives as needed can be added to the polyvinyl acetal resin and mixed to prepare a resin composition for ceramic green chips.

[0099] An inorganic microparticle dispersion slurry composition can be prepared by mixing the above-mentioned ceramic green sheet resin composition, organic solvent and inorganic microparticles.

[0100] The organic solvents mentioned above are not particularly limited. For example, any solvent capable of dissolving the polyvinyl acetal resin is acceptable, such as ketones like acetone, methyl ethyl ketone, dipropyl ketone, and diisobutyl ketone. Alcohols such as methanol, ethanol, isopropanol, and butanol; and aromatic hydrocarbons such as toluene and xylene are also acceptable. Furthermore, esters such as methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, methyl valerate, ethyl valerate, butyl valerate, methyl hexanoate, ethyl hexanoate, butyl hexanoate, 2-ethylhexyl acetate, and 2-ethylhexyl butyrate are also acceptable. Additionally, methyl ceruloxane, ethyl ceruloxane, butyl ceruloxane, terpineol, dihydroterpineol, butyl ceruloxane acetate, butyl carbitol acetate, terpineol acetate, and dihydroterpineol acetate are also acceptable. In particular, regarding coating and drying properties, solvents such as alcohols, ketones, aromatic hydrocarbons, and mixtures thereof are preferred. Among these, mixtures of ethanol and toluene, or mixtures of methyl ethyl ketone and toluene, are even more preferred.

[0101] The content of the organic solvent in the above-mentioned inorganic microparticle dispersion slurry composition is set according to the type of polyvinyl acetal resin used, and is not particularly limited. However, if the content is too low, it will be difficult to achieve the solubility required for mixing. Furthermore, if the content is too high, the viscosity of the slurry composition will be too low, and the processing properties may deteriorate when producing ceramic green sheets. Therefore, the content of organic solvent is preferably 20% by weight or more and 80% by weight or less.

[0102] The above-mentioned inorganic microparticle dispersion slurry composition contains inorganic microparticles. The above-mentioned inorganic microparticles are not particularly limited, and examples include: ceramic powder, glass powder, metal microparticles, etc.

[0103] The above-mentioned ceramic powder is not particularly limited, and examples include oxides, carbides, nitrides, borides, or sulfides of metals or non-metals used in the manufacture of ceramics. Specific examples include oxides, carbides, nitrides, borides, and sulfides of Li, K, Mg, B, Al, Si, Cu, Ca, Sr, Ba, Zn, Cd, Ga, In, Y, lanthanides, actinides, Ti, Zr, Hf, Bi, V, Nb, Ta, W, Mn, Fe, Co, Ni, etc. These ceramic powders can be used alone or in mixtures of two or more. Examples include: barium titanate, aluminum nitride (AlN), silicon nitride (Si3N4), silicon carbide (SiC), aluminum oxide (Al2O3), copper oxide (CuO), spinel compounds, ferrites, zirconium oxide, zircon, barium zirconate, calcium zirconate, titanium oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead zirconate titanate, aluminum oxynitride, silicon nitride, boron nitride, boron carbide, barium stannate, calcium stannate, magnesium silicate, mullite, block talc, cordierite, magnesium silicate, etc.

[0104] The above-mentioned glass powder is not particularly limited. For example, glass powders such as bismuth oxide glass, silicate glass, lead glass, zinc glass, and borosilicate glass can be listed; or glass powders of various silicon oxides such as CaO-Al 2O 3-SiO 2 system, MgO-Al 2O 3-SiO 2 system, and LiO 2-Al 2O 3-SiO 2 system can be listed. Furthermore, as the aforementioned glass powder, mixtures of SnO-B₂O₃-P₂O₅-Al₂O₃, PbO-B₂O₃-SiO₂, BaO-ZnO-B₂O₃-SiO₂, ZnO-Bi₂O₃-B₂O₃-SiO₂, Bi₂O₃-B₂O₃-BaO-CuO, Bi₂O₃-ZnO-B₂O₃-Al₂O₃-SrO, ZnO-Bi₂O₃-B₂O₃, Bi₂O₃-SiO₂, P₂O₅-Na₂O-CaO-BaO-Al₂O₃-B₂O₃, P₂O₅-SnO, and P₂O₅-SnO-B₂O₃ can also be used. Mixtures of SiO₂⁵-SnO-SiO₂, CuO-P₂O₅-RO, SiO₂-B₂O₃-ZnO-Na₂O-Li₂O-NaF-V₂O₅, P₂O₅-ZnO-SnO-R₂O-RO, B₂O₃-SiO₂-ZnO, B₂O₃-SiO₂-Al₂O₃-ZrO₂, SiO₂-B₂O₃-ZnO-R₂O-RO, SiO₂-B₂O₃-Al₂O₃-RO-R₂O, SrO-ZnO-P₂O₅, SrO-ZnO-P₂O₅, BaO-ZnO-B₂O₃-SiO₂, etc. Furthermore, R is selected from elements in the group consisting of Zn, Ba, Ca, Mg, Sr, Sn, Ni, Fe, and Mn. In particular, lead-free glass powders such as PbO-B₂O₃-SiO₂ mixtures, or lead-free glass powders such as BaO-ZnO-B₂O₃-SiO₂ mixtures or ZnO-Bi₂O₃-B₂O₃-SiO₂ mixtures are preferred.

[0105] The aforementioned metal microparticles are not particularly limited, and examples include powders composed of copper, nickel, palladium, iron, platinum, gold, silver, aluminum, tungsten, or alloys thereof. Furthermore, in addition to metal complexes, various types of carbon black and carbon nanotubes may also be used. Additionally, ITO, FTO, niobium oxide, vanadium oxide, tungsten oxide, lanthanum strontium manganite, lanthanum strontium cobalt ferrite, yttrium-stabilized zirconium oxide, cerium oxide doped with thorium, nickel oxide, and lanthanum chromite may also be used.

[0106] The content of the inorganic microparticles in the above-mentioned inorganic microparticle dispersion slurry composition is not particularly limited, but it is preferably 10% by weight or more, more preferably 15% by weight or more, and more preferably 90% by weight or less, more preferably 85% by weight or less. By setting it within the above range, sufficient viscosity and excellent coatability can be achieved, and the dispersibility of the inorganic microparticles can be excellent. The above content is preferably 10 to 90% by weight, more preferably 15 to 85% by weight.

[0107] The above-mentioned inorganic microparticle dispersion slurry composition contains a plasticizer. Examples of such plasticizers include: monomethyl adipate, di(butoxyethyl) adipate, dibutoxyethoxyethyl adipate, triethylene glycol bis(2-ethylhexanoate), triethylene glycol dihexanoate, triethyl acetate, tributyl acetate, dibutyl sebacate, butyl benzyl phthalate, diisononyl adipate, diisodecyl phthalate, tripropionin, neopentyl tetraacetate, di-2-ethylhexyl phthalate, and triacetyl glyceride. Preferably, these are triethylene glycol bis(2-ethylhexanoate), butyl benzyl phthalate, diisononyl adipate, diisodecyl phthalate, tripropionin, neopentyl tetraacetate, and di-2-ethylhexyl phthalate.

[0108] The boiling point of the aforementioned plasticizer is preferably 240°C or higher, and preferably not exceeding 390°C. By setting the boiling point to 240°C or higher, it evaporates easily during the drying process, preventing it from remaining on the molded body. Furthermore, by setting it to not exceeding 390°C, residual carbon can be prevented. The aforementioned boiling point is preferably 240°C or higher and not exceeding 390°C. Moreover, the aforementioned boiling point refers to the boiling point at normal atmospheric pressure.

[0109] The content of the plasticizer in the above-mentioned inorganic microparticle dispersion slurry composition is not particularly limited, but it is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and more preferably 3% by weight or less, more preferably 2.5% by weight or less. By setting it within the above range, the calcination residue of the plasticizer can be reduced. The above content is preferably 0.1 to 3% by weight, more preferably 0.2 to 2.5% by weight.

[0110] The viscosity of the above-mentioned inorganic microparticle dispersion slurry composition is not particularly limited, but when measured at 20°C using a type B viscometer with the probe rotation speed set to 5 rpm, the viscosity is preferably 0.1 Pa·s or higher, and preferably 100 Pa·s or lower. The above-mentioned viscosity is preferably 0.1 to 100 Pa·s. By setting the viscosity to 0.1 Pa·s or higher, after coating using a die-cutting printing method, the obtained inorganic microparticle dispersion sheet can maintain a specified shape. Furthermore, by setting the viscosity to 100 Pa·s or lower, defects such as the coating marks on the die not disappearing can be prevented, resulting in excellent printability.

[0111] There is no particular limitation on the method for preparing the above-mentioned inorganic microparticle dispersion slurry composition. Commonly known stirring methods can be listed. Specifically, the following method can be listed: stirring the above-mentioned resin composition for ceramic green sheets, the above-mentioned inorganic microparticles, organic solvents, plasticizers and other components added as needed using a bead mill.

[0112] The above-mentioned inorganic microparticle dispersion slurry composition is coated onto a support film that has undergone single-sided demolding treatment, and the organic solvent is dried to form a sheet, thereby manufacturing an inorganic microparticle dispersion sheet. The thickness of the above-mentioned inorganic microparticle dispersion sheet is preferably 0.5 μm or more, and preferably 3 μm or less.

[0113] The support membrane used in manufacturing the above-mentioned inorganic microparticle dispersion sheet is preferably a resin membrane that is heat-resistant, solvent-resistant, and flexible. By making the support membrane flexible, the inorganic microparticle dispersion slurry composition can be coated on the surface of the support membrane using a roller coater or a doctor blade coater, and the obtained inorganic microparticle dispersion sheet can be formed into a film and stored and supplied in a rolled state.

[0114] Examples of resins used to form the support film include: polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride and other fluorinated resins, nylon, cellulose, etc. The thickness of the support film is preferably 20 μm or more, and preferably 100 μm or less. Furthermore, it is preferable to perform a release treatment on the surface of the support film, thereby facilitating the easy peeling of the support film during the transfer step.

[0115] Furthermore, by using the above-mentioned inorganic microparticle dispersion slurry composition and inorganic microparticle dispersion sheet in dielectric sheet and electrode paste, multilayer ceramic capacitors can be manufactured.

[0116] The manufacturing method of the above-mentioned multilayer ceramic capacitor preferably includes the following steps: printing conductive paste on the above-mentioned inorganic microparticle dispersion sheet and drying it to make a dielectric sheet; and multiplying the above-mentioned dielectric sheet.

[0117] The above-mentioned conductive paste contains conductive powder. Regarding the material of the conductive powder, there are no particular limitations as long as it is a conductive material; examples include nickel, palladium, platinum, gold, silver, copper, and alloys thereof. These conductive powders can be used alone or in combination of two or more.

[0118] The adhesive resin and organic solvent used in the above conductive paste may be the same as those used in the above inorganic microparticle dispersion slurry composition.

[0119] There are no particular limitations on the method of printing the above conductive paste. For example, screen printing, die coating printing, offset printing, gravure printing, inkjet printing, etc. can be listed.

[0120] In the above-described method for manufacturing a multilayer ceramic capacitor, after laminating, degreasing, and calcining a dielectric sheet printed with the conductive paste, external electrodes are provided, thereby obtaining a multilayer ceramic capacitor. [Effects of the Invention]

[0121] According to the present invention, a resin composition for ceramic green sheets can be provided that has excellent solvent solubility, reduces fine undissolved matter when dissolved in organic solvents, and can produce ceramic capacitors with excellent reliability.

Implementation Method

[0123] The present invention is further described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0124] (Example 1) 200 g of polyvinyl alcohol resin (average degree of polymerization 3,300, degree of saponification 99 mol%, purity 96.5%) was dissolved in 2300 g of pure water and stirred at 90°C for 2 hours. The solution was cooled to 40°C, and 181 g of hydrochloric acid (35% by weight), 3.1 g of malic acid, and 116 g of n-butyraldehyde were added to induce an acetalization reaction, causing the reaction product to precipitate. Subsequently, the reaction was maintained at 40°C for 3 hours to complete the reaction. The mixture was then neutralized, washed with water, and dried using conventional methods to obtain a resin composition for ceramic green sheets containing polyvinyl acetal resin and malic acid. The obtained polyvinyl acetal resin was dissolved in DMSO-D6 (dimethyl sulfoxide) and analyzed using 1H-NMR (nuclear magnetic resonance spectroscopy). The results, including the amounts of acetal groups, acetyl groups, and hydroxyl groups, are shown in Table 1. Furthermore, the content of malic acid in the resin composition for ceramic green sheets was confirmed by ion chromatography, and the result was 2.9 ppm on a weight basis. Moreover, the measuring instrument used was an ICS900 ion chromatography system (manufactured by Thermo Fisher Scientific, column: Ionpac AS22 (4ϕ×250 mm), detector: conductivity meter). Then, the value of X was calculated according to the following formula (2).

[0125]

[0126] (Example 2) Except that tartaric acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0127] (Example 3) Except that 30.9 g of citric acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0128] (Example 4) Except that the amount of n-butyraldehyde added was set to 110 g, the resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0129] (Example 5) Except that hydroxymalonic acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0130] (Example 6) Except that glutaric acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0131] (Example 7) The resin composition for ceramic green sheets was obtained in the same manner as in Example 1, except that 6.2 g of malonic acid was used instead of malic acid.

[0132] (Example 8) 200 g of polyvinyl alcohol resin (average degree of polymerization 3,300, degree of saponification 99 moles, purity 96.5%) was dissolved by adding 2300 g of pure water and stirring at 90°C for 2 hours. The solution was cooled to 40°C, and 181 g of hydrochloric acid (35% by weight), 3.1 g of malic acid, and 116 g of n-butyraldehyde were added to induce an acetalization reaction, causing the reaction product to precipitate. The reaction was then carried out at 40°C for 3 hours to complete the reaction. After neutralization and washing with water using conventional methods, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. Subsequently, 2830 g of pure water and 38.0 g of malic acid were added, and after stirring for 1 hour, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. The mixture was then dried to obtain a resin composition for ceramic green sheets containing polyvinyl acetal resin and malic acid.

[0133] (Example 9) 200 g of polyvinyl alcohol resin (average degree of polymerization 3,300, degree of saponification 82 moles, purity 96.5%) was dissolved by adding 2300 g of pure water and stirring at 90°C for 2 hours. The solution was cooled to 40°C, and 181 g of hydrochloric acid (35% by weight), 3.1 g of malic acid, and 127 g of n-butyraldehyde were added to induce an acetalization reaction, causing the reaction product to precipitate. The reaction was then carried out at 40°C for 3 hours to complete the reaction. After neutralization and washing with water using conventional methods, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. Subsequently, 2640 g of pure water and 76.0 g of malic acid were added, and after stirring for 1 hour, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. The mixture was then dried to obtain a resin composition for ceramic green sheets containing polyvinyl acetal resin and malic acid.

[0134] (Comparative Example 1) The resin composition for ceramic green sheets was obtained in the same manner as in Example 1, except that no malic acid was added.

[0135] (Comparative Example 2) Except that polyvinyl alcohol resin (average degree of polymerization 3,300, degree of saponification 99.2 mol%, purity 96.5%) was used, the amount of n-butyraldehyde added was set to 117 g, and no malic acid was added, the resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0136] (Comparative Example 3) Except that 3.1 g of neopentyl tertrol was used instead of malic acid, the resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0137] (Comparative Example 4) 200 g of polyvinyl alcohol resin (average degree of polymerization 3,300, degree of saponification 78 moles, purity 96.5%) was dissolved by adding 2300 g of pure water and stirring at 90°C for 2 hours. The solution was cooled to 40°C, and 181 g of hydrochloric acid (35% by weight) and 133 g of n-butyraldehyde were added to induce an acetalization reaction, causing the reaction product to precipitate. The reaction was then carried out at 40°C for 3 hours to complete the reaction. After neutralization and washing with water using conventional methods, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. Subsequently, 2590 g of pure water and 132.8 g of neopentyl tertrol were added, and after stirring for 1 hour, the volatile matter was adjusted using a centrifuge to achieve a volatile matter content of 50% by weight. The mixture was then dried to obtain a resin composition for ceramic green sheets containing polyvinyl acetal resin and neopentyl tertrol.

[0138] (Example 10) Except for using polyvinyl alcohol resin (average degree of polymerization 1,700, degree of saponification 99 moles), a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0139] (Example 11) Except that 6.2 g of tartaric acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 10.

[0140] (Example 12) Except that the amount of malic acid added was set to 12.4 g, a resin composition for ceramic green sheets was obtained in the same manner as in Example 10.

[0141] (Comparative Example 5) The resin composition for ceramic green sheets was obtained in the same manner as in Example 10, except that malic acid was not added.

[0142] (Comparative Example 6) Except that the amount of tartaric acid added was set to 1.5 g, the resin composition for ceramic green sheets was obtained in the same manner as in Example 10.

[0143] (Example 13) 200 g of polyvinyl alcohol resin (average degree of polymerization 700, degree of saponification 98.5 moles%) was dissolved by adding 2300 g of pure water to the solution and stirring at 90°C for 2 hours. The solution was cooled to 40°C, and 181 g of hydrochloric acid (35% by weight), 3.1 g of tartaric acid, and 116 g of n-butyraldehyde were added to induce an acetalization reaction, causing the reaction product to precipitate. The reaction was then carried out at 40°C for 3 hours to complete the reaction. After neutralization and washing with water using conventional methods, the solution was adjusted using a centrifuge to reduce the volatile content to 35% by weight. Subsequently, 1630 g of pure water was added, and after stirring for 1 hour, the concentration of the polyvinyl acetal resin was adjusted to 12% by weight using a centrifuge. The solution was then dried to obtain a resin composition for ceramic green sheets containing polyvinyl acetal resin and tartaric acid.

[0144] (Example 14) Except that polyvinyl alcohol resin (average degree of polymerization 700, degree of saponification 98.5 moles%) was used and 6.2 g of tartaric acid was used instead of malic acid, a resin composition for ceramic green sheets was obtained in the same manner as in Example 1.

[0145] (Example 15) Except that the amount of tartaric acid added was set to 12.4 g, a resin composition for ceramic green sheets was obtained in the same manner as in Example 14.

[0146] (Comparative Example 7) Except that polyvinyl alcohol resin (average degree of polymerization 700, degree of saponification 99 moles) was used and tartaric acid was not added, a resin composition for ceramic green sheets was obtained in the same manner as in Example 14.

[0147] <Evaluation> The obtained polyvinyl acetal resin and the resin composition for ceramic green sheets were evaluated as follows. The results are shown in Table 1.

[0148] (1)Porosity For the obtained polyvinyl acetal resin, the porosity was determined by mercury porosimetry using a porosimeter (Thermo Pascal 14B). Furthermore, porosity refers to the volume of pores with a radius of 0.0038 to 7.5 μm that occupy the volume of resin particles.

[0149] (2)Particle size (D50) The particle size (D50) of the obtained polyvinyl acetal resin was determined using a laser diffraction particle size distribution measuring device (Mastersizer 3000).

[0150] (3) Dissolution time: 192 g of a mixed solvent of ethanol and toluene (weight ratio 1:1) was added to a 500 mL beaker as an organic solvent. The temperature was maintained at 25°C. Using two stirrers, while stirring at 200 rpm, 48.0 g of the polyethylene acetal resin composition (average degree of polymerization of resin 3300) obtained in Examples 1-9 and Comparative Examples 1-4 (concentration of resin composition 6% by weight) was added to dissolve the polyethylene acetal resin composition. The dissolution time was visually observed until the undissolved resin disappeared after the addition of the obtained polyethylene acetal resin composition. Similarly, for the polyethylene acetal resin composition (average degree of polymerization of resin 1700) obtained in Examples 10-12 and Comparative Examples 5 and 6, the concentration was set at 10% by weight and the dissolution time was measured. For the polyethylene acetal resin composition (average degree of polymerization of resin 700) obtained in Examples 13-15 and Comparative Example 7, the concentration was set at 20% by weight and the dissolution time was measured.

[0151] (4) Dissolution time reduction rate In Examples 1-9 and Comparative Examples 2-4, the dissolution time reduction rate (%) was calculated based on the dissolution time of Comparative Example 1. Also, in Examples 10-12 and Comparative Example 6, the dissolution time reduction rate (%) was calculated based on the dissolution time of Comparative Example 5. Furthermore, in Examples 13-15, the dissolution time reduction rate (%) was calculated based on the dissolution time of Comparative Example 7. Specifically, the dissolution time reduction rate (%) was calculated according to the following formula: Dissolution time reduction rate (%) = [(Base dissolution time - dissolution time of each example) / Base dissolution time] × 100

[0152] (5) The number of particles with a diameter of 0.5 to 1.0 μm was determined by dissolving the obtained ceramic green sheet in resin composition to make it 0.2% by weight relative to the ethanol-toluene mixture solution with a weight ratio of 1:1. The particle size distribution of 10 mL of the obtained solution was determined using a particle counter (manufactured by RION, KS-42C) to determine the number of particles with a diameter of 0.5 to 1.0 μm per 10 mL.

[0153] (6) Evaluation of ceramic green sheets (Preparation of inorganic dispersion) One part by weight of polyvinyl acetal resin (manufactured by Sekisui Chemicals Co., Ltd., BL-1) was added to a mixed solvent of 20 parts by weight of toluene and 20 parts by weight of ethanol, and stirred to dissolve. Then, 100 parts by weight of barium titanate powder (manufactured by Sakai Chemical Co., Ltd., BT01) was added to the obtained solution, and stirred for 180 minutes using a bead mill (Ready Mill manufactured by AIMEX Co., Ltd.) to prepare an inorganic dispersion.

[0154] (Preparation of Resin Solution) In Examples 1-9 and Comparative Examples 1-4, the obtained resin composition for ceramic green sheets was dissolved in a mixed solvent of ethanol and toluene (weight ratio 1:1) to prepare a resin composition solution with a resin composition concentration of 6% by weight. 2 parts by weight of dioctyl phthalate (DOP) were added to 98 parts by weight of the obtained resin composition solution and stirred to dissolve, thereby preparing a resin solution. Also, in Examples 10-12 and Comparative Examples 5 and 6, the obtained resin composition for ceramic green sheets was dissolved in a mixed solvent of ethanol and toluene (weight ratio 1:1) to prepare a resin composition solution with a resin composition concentration of 8% by weight. 2 parts by weight of DOP were added to 98 parts by weight of the obtained resin composition solution and stirred to dissolve, thereby preparing a resin solution. Furthermore, in Examples 13-15 and Comparative Example 7, the obtained resin composition for ceramic green sheets was dissolved in a mixed solvent of ethanol and toluene (weight ratio 1:1) to prepare a resin composition solution with a resin composition concentration of 15% by weight. 2 parts by weight of DOP were added to 98 parts by weight of the obtained resin composition solution, and the mixture was stirred to dissolve, thereby preparing a resin solution.

[0155] (Preparation of ceramic green sheets) A resin solution is added to the obtained inorganic dispersion, and the mixture is stirred in a bead mill for 90 minutes to obtain a composition for ceramic green sheets. The obtained composition for ceramic green sheets is coated onto a PET film that has undergone demolding treatment to a thickness of 20 μm after drying using a coating machine, and then heated and dried to produce ceramic green sheets.

[0156] (6-1) Number of defects with a cross-sectional area of ​​1 μm² or more: On the surface of the obtained ceramic green sheet, 10 fields of view of 14,000 μm² were randomly selected, and the average number of defects in each field of view was counted using a shape resolution laser microscope (“VK-X100” manufactured by Keynes Corporation). Furthermore, the defect is the portion of the protruding valley with a cross-sectional area of ​​1 μm² or more when the load area ratio is set to 80%.

[0157] (6-2)Arithmetic mean height (Sa) and maximum height (Sz) The arithmetic mean height Sa of the ceramic green sheet was evaluated according to ISO25178 using a three-dimensional surface roughness tester (VertScan2.0 manufactured by Ryoka Systems).

[0158] [Table 1] resin composition evaluate Polyvinyl acetal resin additive X Dissolution time (minute) Dissolution time reduction rate (%) Number of particles with a diameter of 0.5–1.0 μm Ceramic raw slabs Average degree of polymerization Acetal group content (weight%) Acetyl content (weight%) Hydroxyl amount (weight%) porosity (%) D50 (μm) type Number of bases in a compound content (ppm by weight) Cross-sectional area 1 μm 2 The above number of defects Arithmetic mean height Sa (μm) Maximum height Sz (μm) Example 1 3,300 74.5 1.4 24.1 47.5 294 malic acid 2 2.9 1.6 155 26 16,003 489 0.080 3.564 Example 2 3,300 74.5 1.4 24.1 50.8 277 tartaric acid 2 2.7 1.6 148 30 11,991 493 0.083 3.355 Example 3 3,300 74.5 1.4 24.1 51.2 265 Citric acid 3 17.6 1.8 75 64 10,442 288 0.064 2.699 Example 4 3,300 72.4 1.4 26.2 44.5 320 malic acid 2 2.1 1.5 175 17 17,279 763 0.082 3.968 Example 5 3,300 74.5 1.4 24.1 51.0 280 Hydroxymalonic acid 2 2.9 1.6 165 twenty one 16,554 496 0.083 3.341 Example 6 3,300 74.5 1.4 24.1 46.7 291 glutaric acid 2 3.1 1.6 185 12 17,659 881 0.087 3.866 Example 7 3,300 74.5 1.4 24.1 48.4 275 malonic acid 2 5.7 1.8 135 36 11,885 488 0.080 3.551 Example 8 3,300 74.5 1.4 24.1 47.5 294 malic acid 2 13,455 3.5 155 26 15,767 485 0.076 3.145 Example 9 3,300 61.3 23.0 15.7 48.2 353 malic acid 2 28,761 4.4 150 29 14,563 474 0.075 3.138 Comparative Example 1 3,300 74.5 1.4 24.1 46.0 310 - - - - 210 standard 22,185 1,984 0.101 4.986 Comparative Example 2 3,300 75.0 1.1 23.9 66.6 210 - - - - 195 7 20,511 969 0.085 4.311 Comparative Example 3 3,300 73.6 1.4 25.0 47.5 294 Shinbo Shijo 2 2.9 1.6 183 13 19,218 1,051 0.089 4.064 Comparative Example 4 3,300 57.4 27.8 14.9 47.5 294 Shinbo Shijo 2 51,231 4.6 375 -79 29,636 2,126 0.112 5.347

[0159] [Table 2] resin composition evaluate Polyvinyl acetal resin additive X Dissolution time (minute) Dissolution time reduction rate (%) Number of particles with a diameter of 0.5–1.0 μm Ceramic raw slabs Average degree of polymerization Acetal group content (weight%) Acetyl content (weight%) Hydroxyl amount (weight%) porosity (%) D50 (μm) type Number of bases in a compound content (ppm by weight) Cross-sectional area 1 μm 2 The above number of defects Arithmetic mean height Sa (μm) Maximum height Sz (μm) Example 10 1,700 76.9 1.4 21.7 31.8 441 malic acid 2 2.8 1.7 25 17 2,981 791 0.074 3.503 Example 11 1,700 76.9 1.4 21.7 33.2 430 tartaric acid 2 5.6 1.8 20 33 2,329 583 0.069 3.492 Example 12 1,700 76.9 1.4 21.7 32.7 425 malic acid 2 8.0 1.9 20 33 3,106 601 0.066 3.018 Comparative Example 5 1,700 76.9 1.4 21.7 30.0 412 - - - - 30 benchmark 5,826 2,317 0.090 4.944 Comparative Example 6 1,700 75.3 1.3 23.3 31.2 315 tartaric acid 2 1.9 1.5 30 0 4,931 872 0.070 3.324

[0160] [Table 3] resin composition evaluate Polyvinyl acetal resin additive X Dissolution time (minute) Dissolution time reduction rate (%) Number of particles with a diameter of 0.5–1.0 μm Ceramic raw slabs Average degree of polymerization Acetal group content (weight%) Acetyl content (weight%) Hydroxyl amount (weight%) porosity (%) D50 (μm) type Number of bases in a compound content (ppm by weight) Cross-sectional area 1 μm 2 The above number of defects Arithmetic mean height Sa (μm) Maximum height Sz (μm) Example 13 700 76.6 2.0 21.3 28.3 324 tartaric acid 2 3.7 1.8 15 25 1,378 273 0.058 2.722 Example 14 700 76.6 2.0 21.3 29.6 201 tartaric acid 2 5.7 1.9 12 40 981 354 0.070 2.791 Example 15 700 76.6 2.0 21.3 30.2 223 tartaric acid 2 7.6 2.0 10 50 868 332 0.071 2.776 Comparative Example 7 700 76.9 1.4 21.7 23.0 200 - - - - 20 benchmark 2,456 2,546 0.088 6.697 [Industrial Applicability]

[0161] According to the present invention, a resin composition for ceramic green sheets can be provided that has excellent solvent solubility, reduces fine undissolved matter when dissolved in organic solvents, and is capable of producing ceramic capacitors with excellent reliability. [Simplified Explanation of the Diagram]

[0122] None

Claims

1. A resin composition for ceramic green sheet, comprising polyvinyl acetal resin and compound A represented by the following formula (1), wherein the content of compound A is 2 ppm or more by weight, wherein in formula (1), R1 and R3 independently represent carboxyl groups or their salts, and R2 represents a linear alkyl group having 1 to 3 carbon atoms, having at least one of the groups consisting of hydroxyl groups, carboxyl groups and their salts.

2. The resin composition for ceramic green sheets as claimed in claim 1, wherein, The X represented by the following formula (2) is 1.6 or more and 4.5 or less.

3. The resin composition for ceramic green sheets as claimed in claim 1 or 2, wherein, Compound A is selected from at least one compound from the group consisting of tartaric acid, malic acid, citric acid and their salts.

4. The resin composition for ceramic green sheets as claimed in claim 1 or 2, wherein, The solution obtained by dissolving 10% by weight of polyvinyl acetal resin in a mixed solution of ethanol / toluene (weight ratio 1:1) has a viscosity of 50 mPa·s or higher at 20°C.

5. The resin composition for ceramic green sheets as claimed in claim 1 or 2, wherein, The acetylation content of polyvinyl acetal resin is more than 0.5% by weight and less than 20% by weight.

6. The resin composition for ceramic green sheets as claimed in claim 1 or 2, wherein, The average degree of polymerization of polyvinyl acetal resin is above 500.