Polyvinyl acetal resin composition, inorganic fine particle dispersion vehicle composition, inorganic fine particle dispersion slurry composition, and multilayer ceramic capacitors

Abstract

The present invention provides a polyvinyl acetal resin composition that is highly soluble to organic solvents, and that, when being dissolved in an organic solvent, produces less undissolved fine objects. Also provided is a polyvinyl acetal resin composition from which it is possible to produce a ceramic laminate in which oxygen defects derived from undissolved objects are less likely to occur and which has excellent characteristics. Further provided are: a vehicle composition that is for dispersing inorganic fine particles and that contains the polyvinyl acetal resin composition; an inorganic fine particle-dispersed slurry composition; and a multilayer ceramic capacitor obtained using said inorganic fine particle-dispersed slurry composition. The present invention pertains to a polyvinyl acetal resin composition that contains a polyvinyl acetal resin and a cationic surfactant. The primary particle size of the polyvinyl acetal resin is 0.01-10 μm. The cationic surfactant is contained in an amount of 1-10000×10-6 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin.

Description

[Technical Field]

[0001] The present invention relates to a polyvinyl acetal resin composition, a vehicle composition for dispersing inorganic fine particles, an inorganic fine particle dispersion slurry composition, and a multilayer ceramic capacitor. [Background technology]

[0002] In recent years, electronic components used in various electronic devices have become smaller and more layered, and multilayer electronic components such as multilayer circuit boards, multilayer coils, and multilayer ceramic capacitors are widely used. In particular, multilayer ceramic capacitors are generally manufactured through the following process. First, a binder resin such as polyvinyl butyral resin or poly(meth)acrylic acid ester resin is dissolved in an organic solvent, and plasticizers, dispersants, etc., are added to the solution. Then, ceramic raw material powder is added and the mixture is uniformly mixed using a mixing device such as a bead mill or ball mill. After degassing, a ceramic slurry composition with a constant viscosity is obtained. This slurry composition is cast onto a support surface such as a release-treated polyethylene terephthalate film or SUS plate using a doctor blade, reverse roll coater, etc. After evaporating volatile components such as solvents by heating, the slurry composition is peeled off from the support to obtain a ceramic green sheet. Next, multiple sheets of the obtained ceramic green sheet, onto which conductive paste that will serve as the internal electrodes is screen-printed, are stacked alternately and heated and pressed together to create a laminate. Subsequently, a process called degreasing is performed to remove binder resin components and other substances contained in the laminate, and then external electrodes are sintered onto the end faces of the ceramic sintered body obtained by firing, thereby obtaining a multilayer ceramic capacitor.

[0003] Polyvinyl acetal resin used in the production of ceramic green sheets is generally used as a solution dissolved in organic solvents such as methyl ethyl ketone, toluene, alcohol, and mixtures thereof. However, conventional polyvinyl acetal resins produced trace amounts of undissolved material when dissolved in organic solvents. The presence of such undissolved material led to a decrease in the electrical properties of the resulting product when used in multilayer ceramic capacitors, as voids were more likely to remain during the degreasing and firing processes, and the dispersibility of ceramic powders and other materials was reduced. Therefore, when using polyvinyl acetal resin for ceramic green sheet applications, it was necessary to blend in organic and inorganic compounds, dissolve them in organic solvents, and then remove undissolved materials through a filtration process.

[0004] In contrast, Patent Document 1 proposes a polyvinyl acetal resin in which, when a 5% by weight solution of the polyvinyl acetal resin, prepared by dissolving it in a 1:1 mixed solvent of methyl ethyl ketone and / or toluene and ethanol, is filtered using a 5 μm mesh filter at a filtration temperature of 25°C and a filtration pressure of 10 mmHg, the reduction in filtration flow rate is less than 10%. Furthermore, it is stated that using such a polyvinyl acetal resin can improve productivity by reducing undissolved material when dissolved in an organic solvent and shortening the filtration time. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-325342 [Overview of the project] [Problems that the invention aims to solve]

[0006] On the other hand, in recent years, with the increasing multi-functionality and miniaturization of electronic devices, multilayer ceramic capacitors are required to be both high-capacity and compact. To meet these demands, it is necessary to sufficiently remove even finer undissolved material. However, even with the polyvinyl acetal resin described in Patent Document 1, it is not possible to sufficiently remove even finer undissolved material, and it is necessary to remove the undissolved material by filtration or other methods, which leads to a decrease in productivity. Furthermore, there is a problem that minute undissolved material with a primary particle size of about 0.1 to 1 μm cannot be filtered and concentrated.

[0007] The present invention aims to provide a polyvinyl acetal resin composition that exhibits high solubility in organic solvents and produces few fine undissolved particles when dissolved in organic solvents. Furthermore, it aims to provide a polyvinyl acetal resin composition that is less prone to generating oxygen defects originating from undissolved particles and that enables the production of ceramic laminates with excellent properties. The present invention also aims to provide an inorganic fine particle dispersion vehicle composition containing the polyvinyl acetal resin composition, an inorganic fine particle dispersion slurry composition, and a laminated ceramic capacitor using the inorganic fine particle dispersion slurry composition. [Means for solving the problem]

[0008] (1) This disclosure relates to a composition containing a polyvinyl acetal resin and a cationic surfactant, wherein the primary particle size of the polyvinyl acetal resin is 0.01 μm or more and 10 μm or less, and the cationic surfactant is present in a concentration of 1 × 10¹⁶ per 100 parts by weight of the polyvinyl acetal resin. -6 Weight part or more 10000×10 -6 This is a polyvinyl acetal resin composition containing less than or equal to parts by weight of [amount]. Disclosure (2) is a polyvinyl acetal resin composition according to Disclosure (1), wherein the polyvinyl acetal resin has a degree of polymerization of 1500 to 2000, a hydroxyl group content of 25.0 mol% to 35.0 mol%, an acetal group content of 60.0 mol% to 70.0 mol%, and an acetyl group content of 0.1 mol% to 0.5 mol%. Disclosure (3) is a polyvinyl acetal resin composition according to Disclosure (1) or (2), wherein the cationic surfactant has a solubility in ethanol of 0.001 g / 100 g or more. This disclosure (4) provides p-toluenesulfonic acid or a salt thereof in a quantity of 1 × 10 per 100 parts by weight of polyvinyl acetal resin. -6 Weight part or more 500×10 -6 A polyvinyl acetal resin composition containing any combination of any of (1) to (3) of the present disclosure, in amounts by weight or less. Disclosure (5) is a polyvinyl acetal resin composition in any combination of any of Disclosures (1) to (4), wherein the secondary particle size is measured by laser diffraction scattering particle size distribution measurement, and when the particle sizes of 10%, 50%, and 90% of the volume-based cumulative particle size from the smallest particle size side are defined as D10, D50, and D90, respectively, (D90-D10) / D50 is 0.7 or more and 1.5 or less. Disclosure (6) is a polyvinyl acetal resin composition in any combination of any of Disclosures (1) to (5), wherein the polyvinyl acetal resin has a molecular weight distribution (Mw / Mn), which is the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn, of 1.8 or more and 2.6 or less. Disclosure (7) is an inorganic fine particle dispersion vehicle composition containing any of the polyvinyl acetal resin compositions of Disclosure (1) to (6) and an organic solvent. The present disclosure (8) is an inorganic microparticle dispersion slurry composition containing the inorganic microparticle dispersion vehicle composition, inorganic microparticles, and a plasticizer of the present disclosure (7). The present disclosure (9) is a multilayer ceramic capacitor made using the inorganic fine particle dispersion slurry composition of the present disclosure (8). The present invention will be described in detail below.

[0009] The inventors have found that by synthesizing a polyvinyl acetal resin having a primary particle size within a predetermined range, the solubility in a solvent is improved and the amount of undissolved matter is reduced. Furthermore, they have found that by adding a predetermined amount of a cationic surfactant, polyvinyl acetal resin having a small particle size can be aggregated. Also, since the primary particle size is smaller than that of conventional polyvinyl acetal resins, it has been found that the dissolution time can be shortened. Further, by using such a polyvinyl acetal resin composition, it has been found that a ceramic green sheet capable of producing a highly reliable multilayer ceramic capacitor with few sheet defects can be produced, leading to the completion of the present invention.

[0010] The polyvinyl acetal resin composition of the present invention contains a polyvinyl acetal resin. The above polyvinyl acetal resin has a fine particle shape. The above polyvinyl acetal resin has a primary particle size of 0.01 μm or more and 10 μm or less. By using such a polyvinyl acetal resin, even when dissolved in a solvent, the amount of undissolved matter is very small, and the dissolution time can be shortened. Also, variations in the shape and composition such as the particle size of the polyvinyl acetal resin are reduced, and a highly reliable multilayer ceramic capacitor can be obtained. Since the primary particle size of the above polyvinyl acetal resin can reduce the fine particles contained in the filtrate, it is preferably 0.05 μm or more, more preferably 0.1 μm or more. Also, since the dissolution time can be shortened, it is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. Note that a primary particle means one particle before aggregation, and a secondary particle means an aggregated particle. The CV value of the primary particle size of the above polyvinyl acetal resin is preferably 15% or more, more preferably 20% or more, preferably 40% or less, and more preferably 35% or less. By setting it within the above range, the solubility in a solvent can be increased and the insoluble components can be reduced. The primary particle diameter of the above polyvinyl acetal resin can be determined by observing with a scanning electron microscope (for example, "Regulus8220" manufactured by Hitachi High-Technologies Corporation), measuring the maximum Feret diameter of 100 primary particles, and obtaining the average value. The maximum Feret diameter is the maximum distance between parallel tangents contacting the opposing contour lines of the particle. The above primary particle diameter can be adjusted by controlling the size of the micelles by adjusting the type and amount of the anionic surfactant used in the production of the polyvinyl acetal resin.

[0011] Since the above polyvinyl acetal resin can sufficiently increase the mechanical strength when producing a thin film ceramic green sheet, the degree of polymerization is preferably 300 or more, more preferably 600 or more, and still more preferably 1500 or more. Also, from the viewpoints of solubility in organic solvents and dissolution viscosity, the degree of polymerization is preferably 8000 or less, more preferably 7000 or less, and still more preferably 2000 or less.

[0012] The above polyvinyl acetal resin preferably has a structural unit having an acetal group represented by the following formula (1), a structural unit having a hydroxyl group represented by the following formula (2), and a structural unit having an acetyl group represented by the following formula (3).

[0013]

Chemical formula

[0014] In the above formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0015] In the above formula (1), R 1When the alkyl group has 1 to 20 carbon atoms, examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and octadecyl groups. Among these, methyl and n-propyl groups are preferred.

[0016] In the above polyvinyl acetal resin, the content of constituent units having an acetal group represented by the above formula (1) (hereinafter also referred to as "acetal group content") is preferably 45.0 mol% or more, more preferably 50.0 mol% or more, even more preferably 55.0 mol% or more, and particularly preferably 60.0 mol% or more, from the viewpoint of solubility in organic solvents. Furthermore, in order to obtain a polyvinyl acetal resin with excellent toughness, it is preferably 80.0 mol% or less, more preferably 78.0 mol% or less, even more preferably 76.0 mol% or less, and particularly preferably 70.0 mol% or less. The amount of acetal group can be measured, for example, by NMR. Regarding the calculation method for the amount of acetal groups, since the acetal groups in polyvinyl acetal resin are obtained by acetalizing two hydroxyl groups of polyvinyl alcohol, the method of counting the two acetalized hydroxyl groups is adopted.

[0017] In the above polyvinyl acetal resin, the content of constituent units having hydroxyl groups represented by the above formula (2) (hereinafter also referred to as "hydroxyl group content") is preferably 18.0 mol% or more, more preferably 20.0 mol% or more, even more preferably 22.0 mol% or more, and particularly preferably 25.0 mol% or more, in order to produce a polyvinyl acetal resin with excellent toughness. Furthermore, from the viewpoint of solubility in organic solvents, it is preferably 40.0 mol% or less, more preferably 39.0 mol% or less, even more preferably 38.0 mol% or less, and particularly preferably 35.0 mol% or less. The amount of hydroxyl groups can be measured, for example, by NMR.

[0018] In the above polyvinyl acetal resin, the content of the constituent unit having an acetyl group represented by the above formula (3) (hereinafter also referred to as "acetyl group content") is preferably 0.01 mol% or more, more preferably 0.05 mol% or more, and even more preferably 0.1 mol% or more, in order to suppress the increase in viscosity of the ceramic green sheet composition due to intramolecular and intermolecular hydrogen bonding of hydroxyl groups in the polyvinyl acetal resin. Furthermore, in order to reduce the micelle diameter during the synthesis of the polyvinyl acetal resin and to produce finer particles, it is preferably 5.0 mol% or less, more preferably 3.0 mol% or less, even more preferably 1.0 mol% or less, and particularly preferably 0.5 mol% or less. The amount of acetyl groups can be measured, for example, by NMR.

[0019] The polyvinyl acetal resin described above preferably has a weight-average molecular weight (Mw) of 200,000 or more, more preferably 250,000 or more, preferably 450,000 or less, and more preferably 400,000 or less. By setting the molecular weight within this range, it is possible to improve the strength of the green sheet while also improving its solubility. The polyvinyl acetal resin described above preferably has a number average molecular weight (Mn) of 10,000 or more, more preferably 11,000 or more, preferably 180,000 or less, and more preferably 170,000 or less. By setting the molecular weight within the above range, it is possible to improve the strength of the green sheet while also improving its solubility. The above polyvinyl acetal resin preferably has a molecular weight distribution (Mw / Mn), which is the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), of 1.0 or higher, more preferably 1.8 or higher, even more preferably 2.0 or higher, preferably 2.6 or lower, more preferably 2.5 or lower, and even more preferably 2.4 or lower. By setting it within the above range, solubility can be improved. The above Mw and Mn can be measured, for example, by gel permeation chromatography (GPC) using an appropriate standard (e.g., a polystyrene standard). Examples of columns used when measuring Mw and Mn include TSKgel SuperHZM-H.

[0020] The above polyvinyl acetal resin is measured by a laser diffraction scattering particle size distribution method, and when the particle sizes at 10%, 50%, and 90% of the volume-based cumulative total are defined as D10, D50, and D90, respectively, it is preferable that (D90-D10) / D50 is 0.7 or higher, more preferably 0.8 or higher, and even more preferably 0.9 or higher. Furthermore, it is preferable that it is 1.5 or lower, more preferably 1.4 or lower, and even more preferably 1.3 or lower. By setting the range as described above, solubility can be improved. The D10, D50, and D90 measurements using the laser diffraction / scattering particle size distribution analyzer can be performed, for example, by supplying an aqueous solution containing dispersed polyvinyl acetal resin to a laser diffraction / scattering particle size distribution analyzer, such as the LA-950 manufactured by Horiba, Ltd.

[0021] From the viewpoint of preventing clogging during the filtration process in manufacturing, the above polyvinyl acetal resin preferably has a D10 of 40 μm or more, more preferably 50 μm or more, and even more preferably 60 μm or more. Furthermore, from the viewpoint of shortening the dissolution time, the D10 is preferably 140 μm or less, more preferably 130 μm or less, and even more preferably 120 μm or less.

[0022] From the viewpoint of preventing clogging during the filtration process in manufacturing, the above polyvinyl acetal resin preferably has a D50 of 100 μm or more, more preferably 110 μm or more, and even more preferably 120 μm or more. Furthermore, from the viewpoint of shortening the dissolution time, it is even more preferable that the D50 is 200 μm or less, more preferably 190 μm or less, and even more preferably 180 μm or less.

[0023] From the viewpoint of preventing clogging during the filtration process in manufacturing, the above polyvinyl acetal resin preferably has a D90 of 180 μm or more, more preferably 190 μm or more, and even more preferably 200 μm or more. Furthermore, from the viewpoint of shortening the dissolution time, the D90 is preferably 280 μm or less, more preferably 270 μm or less, and even more preferably 260 μm or less.

[0024] The above D10, D50, D90, and (D90-D10) / D50 can be adjusted by the type and amount of cationic surfactant used in the production of polyvinyl acetal resin.

[0025] The polyvinyl acetal resin content in the polyvinyl acetal resin composition of the present invention is preferably 95% by weight or more, more preferably 97% by weight or more, preferably 100% by weight or less, and more preferably 99% by weight or less.

[0026] The above-mentioned polyvinyl acetal resin can usually be produced by acetalizing polyvinyl alcohol resin.

[0027] As the polyvinyl alcohol resin mentioned above, conventionally known polyvinyl alcohol resins can be used, such as resins produced by saponifying polyvinyl acetate resins with alkali, acid, ammonia water, etc. The above-mentioned polyvinyl alcohol resin may be fully saponified, but it does not need to be fully saponified if there is at least one unit with a double hydroxyl group at the meso or racemo position at least one location in the main chain; it may be a partially saponified polyvinyl alcohol resin.

[0028] The above polyvinyl alcohol resin preferably has a degree of saponification of 90.0 mol% or more, more preferably 95.0 mol% or more, even more preferably 99.5 mol% or more, preferably 99.99 mol% or less, more preferably 99.95 mol% or less, and even more preferably 99.9 mol% or less. By using the above range, it is possible to form uniform, small micelles by combining them with an organic sulfonic acid catalyst and anionic surfactant, and the amount of undissolved components can be reduced by acetalizing within these micelles.

[0029] The above acetalization can be carried out, for example, by adding and dissolving polyvinyl alcohol resin in water, a mixed solvent of water and a water-compatible organic solvent, or an organic solvent, and then adding an anionic surfactant, an acid catalyst such as an organic sulfonic acid catalyst, and an aldehyde, stirring with a homogenizer or the like to form emulsified micelles, and allowing the reaction to proceed within the micelles. The above micelles are formed from polyvinyl alcohol resin, an anionic surfactant, an acid catalyst, and an aldehyde. By using the method described above, it is possible to produce a polyvinyl acetal resin that is fine and has little variation in particle size, shape, and composition. Furthermore, by using an organic sulfonic acid catalyst as the acid catalyst, it is not necessary to cool to low temperatures, which is required when using hydrochloric acid catalysts, etc., and high-quality polyvinyl acetal resin can be produced efficiently.

[0030] As the above-mentioned organic solvent that is compatible with water, for example, an alcohol-based organic solvent can be used. Examples of the above-mentioned organic solvents include alcohol-based organic solvents, aromatic organic solvents, aliphatic ester-based solvents, ketone-based solvents, lower paraffin-based solvents, ether-based solvents, amide-based solvents, and amine-based solvents. Examples of the above-mentioned alcohol-based organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol. Examples of the above-mentioned aromatic organic solvents include xylene, toluene, ethylbenzene, and methyl benzoate. Examples of the above-mentioned 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 the ketone-based solvents mentioned above include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, benzophenone, and acetophenone. Examples of the lower paraffinic solvents mentioned above include hexane, pentane, octane, cyclohexane, and decane. Examples of the above-mentioned ether-based solvents include diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol diethyl ether. Examples of the above-mentioned amide solvents include N,N-dimethylformamide, N,N-dimethyltesetamide, N-methylpyrrolidone, and acetanilide. Examples of the above-mentioned amine-based solvents include ammonia, trimethylamine, triethylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, aniline, N-methylaniline, N,N-dimethylaniline, and pyridine. These can be used individually or as a mixture of two or more solvents. Among these, ethanol, n-propanol, isopropanol, and tetrahydrofuran are particularly preferred from the viewpoint of resin solubility and ease of purification.

[0031] The amount of water, mixed solvent, or organic solvent added is preferably 500 parts by weight or more, more preferably 600 parts by weight or more, preferably 2000 parts by weight or less, and more preferably 1800 parts by weight or less, per 100 parts by weight of polyvinyl alcohol resin. By setting the range as described above, stable micelles can be formed during acetalization.

[0032] Examples of the above-mentioned anionic surfactants include those used as emulsifiers added during emulsion polymerization, such as alkyl sulfonates. Examples of the alkyl sulfonates mentioned above include sodium salts, potassium salts, and ammonium salts of octyl sulfonic acid, decyl sulfonic acid, and dodecyl sulfonic acid.

[0033] The amount of the above-mentioned anionic surfactant added is preferably 0.5 parts by weight or more, more preferably 2 parts by weight or more, preferably 200 parts by weight or less, and more preferably 70 parts by weight or less, per 100 parts by weight of the polyvinyl alcohol resin. By setting the range as described above, stable micelles can be formed during acetalization.

[0034] Examples of the acid catalysts mentioned above 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; alkyl sulfonic acids such as dodecyl sulfonic acid and lauryl sulfonic acid; aromatic sulfonic acids such as benzene sulfonic acid and p-toluenesulfonic acid; and organic sulfonic acids such as polyoxyethylene sulfonic acid. Among these, sulfonic acids are preferred, and because they also act as emulsifiers, p-toluenesulfonic acid, aromatic sulfonic acids such as benzene sulfonic acid, alkyl sulfonic acids such as dodecyl sulfonic acid and lauryl sulfonic acid, and polyoxyethylene sulfonic acid, which has excellent micelle-forming properties, are preferred. Furthermore, p-toluenesulfonic acid is more preferred. In methods using hydrochloric acid as an acid catalyst, it is necessary to add the catalyst at low temperatures to control the particle size. However, when using sulfonic acid as an acid catalyst, it is not necessary to keep the reaction system at low temperatures.

[0035] The amount of the above-mentioned acid catalyst added is preferably 5 parts by weight or more, more preferably 20 parts by weight or more, preferably 200 parts by weight or less, and more preferably 70 parts by weight or less, per 100 parts by weight of polyvinyl acetal resin. By setting the range as described above, stable micelles can be formed during acetalization.

[0036] In the above method for producing polyvinyl acetal resin, it is preferable to dissolve the polyvinyl alcohol resin by adding it to a solvent and stirring it at a temperature of 90°C or higher for 2 hours or more. Furthermore, it is preferable to then return it to room temperature, add an aldehyde, an anionic surfactant, an acid catalyst such as a sulfonic acid catalyst, emulsify it with a high-speed stirrer, and heat it to 30-50°C to carry out the acetalization reaction. By performing the above procedure, the polyvinyl alcohol resin is sufficiently dissolved, the amount of acetal groups is sufficiently increased, and the generation of undissolved material can be suppressed.

[0037] The aldehyde used in the above acetalization is not particularly limited, and examples include aliphatic aldehydes and aromatic aldehydes. Examples of the above-mentioned aliphatic aldehydes include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, n-hexylaldehyde, 2-ethylbutyraldehyde, 2-ethylhexylaldehyde, n-heptylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, and amylaldehyde. Examples of the above aromatic aldehydes include benzaldehyde, cinnamaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, and β-phenylpropionaldehyde. These aldehydes may be used individually or in combination of two or more.

[0038] The amount of aldehyde added can be appropriately set according to the amount of acetal groups in the polyvinyl acetal resin. In particular, it is preferable to add 300 parts by weight or more, more preferably 400 parts by weight or more, preferably 1500 parts by weight or less, and most preferably 1000 parts by weight or less, per 100 parts by weight of polyvinyl alcohol resin. By setting the range as described above, the degree of acetalization can be adjusted to a desirable range.

[0039] For the above acetalization, it is preferable to emulsify the mixture of polyvinyl alcohol, anionic surfactant, organic sulfonic acid catalyst, and aldehyde in a reaction vessel after weighing them. There are no particular limitations on the means of emulsification, but examples include high-speed agitators such as homogenizers and dispersers, and vacuum emulsifiers. Since the emulsifying device described above may cause excessive foaming, an antifoaming agent may be added. The antifoaming agent is not particularly limited, but examples include silicone-based antifoaming agents, polyacetylene-based antifoaming agents, and low-polarity alcohol antifoaming agents. Among these, silicone-based antifoaming agents are preferred because they are highly effective even in small amounts.

[0040] The reaction temperature of the acetalization reaction is preferably 15°C or higher, more preferably 20°C or higher, still more preferably 30°C or higher, preferably 50°C or lower, and more preferably 40°C or lower. Also, the reaction time is preferably 1.5 hours or longer, preferably 2 hours or longer, preferably 8 hours or shorter, and more preferably 7 hours or shorter.

[0041] In the method for producing the polyvinyl acetal resin, it is preferable to perform neutralization with an alkali. Examples of the alkali include sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and the like. Also, it is preferable to wash the polyvinyl acetal resin obtained using water or the like before and after the neutralization step. In order to prevent the mixing of impurities contained in the washing water, it is more preferable to perform the washing with pure water.

[0042] In the present invention, the obtained polyvinyl acetal resin is dispersed in water in the form of fine particles having a primary particle diameter of 0.01 μm or more and 10 μm or less. In this state, it is difficult to filter with a filter cloth, and furthermore, it is necessary to add a cationic surfactant described later to cause aggregation.

[0043] The polyvinyl alcohol resin composition of the present invention contains 1×10 -6 parts by weight or more and 10000×10 -6 parts by weight or less of a cationic surfactant with respect to 100 parts by weight of the polyvinyl acetal resin. By adding a predetermined amount of a cationic surfactant to the polyvinyl acetal resin, fine polyvinyl acetal resin can be aggregated, and fine undissolved matter can be reduced. Also, an acid catalyst such as an anionic surfactant or an organic sulfonic acid catalyst can be easily removed by filtration washing. The content of the cationic surfactant is 5×10 -6Preferably, it is 10 × 10 -6 It is more preferable that it be greater than or equal to the weight, 500 x 10 -6 Preferably, it is less than or equal to parts by weight, 100 × 10 -6 It is more preferable that the amount be less than or equal to parts by weight. The content of the above-mentioned cationic surfactant can be confirmed, for example, by DART-MS (Direct Ionization Mass Spectrometry).

[0044] Examples of the cationic surfactants mentioned above include quaternary ammonium salts, aliphatic amine salts, aromatic amine salts, heterocyclic amine salts, and phosphonium salts. Examples of the above quaternary ammonium salts include tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium chloride, hexyltrimethylammonium bromide, n-octyltrimethylammonium bromide, n-octyltrimethylammonium chloride, nonyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium hexafluorophosphate, hexadecyltrimethylammonium tetrafluoroborate, hexadecyltrimethylammonium perchlorate, and hexadecyltrimethylammonium hydroxy Examples include hexadecyltrimethylammonium bisulfate, heptadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, benzyldodecyldimethylammonium chloride, benzyldodecyldimethylammonium bromide, benzyldimethyltetradecylammonium chloride, benzylhexadecyldimethylammonium chloride, benzyldimethyloctadecylammonium chloride, benzalkonium chloride, benzethonium chloride, dodecane-1-yl(ethyl)(dimethyl)ammonium=ethyl=sulfate, distearyldimethylammonium chloride, docosyltrimethylammonium chloride, 1-dodecylpyridinium chloride, hexadecylpyridinium chloride, hexadecylpyridinium bromide, 1-hexadecyl-4-methylpyridinium chloride, 1-ethyl-3-methylimidazolium chloride, cetylpyridinium chloride, and benzethonium chloride. Examples of the above-mentioned amine salts include n-octylammonium chloride, n-octylammonium bromide, dodecylamine hydrochloride, dodecylammonium bromide, and octadecylamine hydrochloride. Examples of the phosphonium salts mentioned above include trans-2-butene-1,4-bis(triphenylphosphonium chloride), tributyl(cyanomethyl)phosphonium chloride, (2-carboxyethyl)triphenylphosphonium bromide, tributyldodecylphosphonium bromide, tributylhexadecylphosphonium bromide, tributyl-n-octylphosphonium bromide, tetrakis(hydroxymethyl)phosphonium chloride, tetraphenylphosphonium bromide, tetrakis(hydroxymethyl)phosphonium sulfate, tetrabutylphosphonium bromide, tetraphenylphosphonium chloride, tetraethylphosphonium bromide, tetrabutylphosphonium chloride, tetra-n-octylphosphonium bromide, tetraethylphosphonium tetrafluoroborate, tetrabutylphosphonium tetrafluoroborate, tetrabutylphosphonium hexafluorophosphate, tetrabutylphosphonium tetraphenylborate, and tributylhexylphosphonium bromide. Among these, quaternary ammonium salts, heterocyclic amine salts, and phosphonium salts are preferred, and quaternary ammonium salts are more preferred, including 1-ethyl-3-methylimidazolium chloride, cetylpyridinium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, hexyltrimethylammonium bromide, n-octyltrimethylammonium bromide, n-octyltrimethylammonium chloride, nonyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, Dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, benzyldodecyldimethylammonium chloride, dodecan-1-yl(ethyl)(dimethyl)ammonium=ethyl=sulfate, hexadecyltrimethylammonium bromide, tetraethylammonium bromide, and benzethonium chloride are even more preferred.

[0045] The above-mentioned cationic surfactant preferably has a solubility in ethanol of 0.001 g / 100 g or more, and more preferably 0.005 g / 100 g or more. By using a cationic surfactant whose solubility in ethanol is above the lower limit mentioned above, it is possible to prevent a significant amount of cationic surfactant residue from remaining on the resin. The solubility in ethanol mentioned above can be measured using the solubility at 25°C.

[0046] The polyvinyl acetal resin composition of the present invention may contain p-toluenesulfonic acid or a salt thereof. The content of the above-mentioned p-toluenesulfonic acid or its salt in the polyvinyl acetal resin composition of the present invention is 1 × 10 per 100 parts by weight of the above-mentioned polyvinyl acetal resin. -6 It is preferable that it is 500 × 10 -6 It is preferable that the amount be less than or equal to parts by weight. By setting the range as described above, secondary aggregation is maintained through interaction with the anionic surfactant, and the generation of fine particles during use can be suppressed. The content of the above-mentioned p-toluenesulfonic acid or its salt is 1 × 10 -6 It is more preferable that the weight is greater than or equal to 300 × 10 -6 It is more preferable that the amount be less than or equal to parts by weight. The content of the above-mentioned p-toluenesulfonic acid or its salt can be confirmed, for example, by DART-MS (direct ionization mass spectrometry).

[0047] The polyvinyl acetal resin composition of the present invention may contain an anionic surfactant. Examples of anionic surfactants include those used in the production of the polyvinyl acetal resin mentioned above. The content of the anionic surfactant in the polyvinyl acetal resin composition of the present invention is preferably 0 parts by weight or more per 100 parts by weight of the polyvinyl acetal resin, and 10 × 10 -6It is more preferable that it be greater than or equal to the weight, 500 x 10 -6 Preferably, it is less than or equal to the weight, 300 x 10 -6 It is more preferable that the amount be less than or equal to parts by weight.

[0048] One method for producing the polyvinyl acetal resin composition of the present invention is to add a cationic surfactant to a solution containing the polyvinyl acetal resin obtained by producing the above-mentioned polyvinyl acetal resin, mix the mixture, and dry it. Another method is to add a cationic surfactant during the acetalization step when producing the above-mentioned polyvinyl acetal resin, followed by neutralization, washing with water, and drying. Furthermore, it is preferable that the polyvinyl acetal resin composition of the present invention is synthesized by an acetal reaction in micelles formed from a polyvinyl alcohol resin and an anionic surfactant.

[0049] A vehicle composition for dispersing inorganic fine particles can be prepared using the polyvinyl acetal resin composition and organic solvent of the present invention. The present invention also includes a polyvinyl acetal resin composition and an inorganic fine particle dispersion vehicle composition containing an organic solvent.

[0050] The inorganic fine particle dispersion vehicle composition of the present invention contains the above-mentioned polyvinyl acetal resin. The content of the polyvinyl acetal resin in the inorganic fine particle dispersion vehicle composition of the present invention is preferably 3% by weight or more, more preferably 5% by weight or more, preferably 10% by weight or less, and more preferably 8% by weight or less.

[0051] The inorganic fine particle dispersion vehicle composition of the present invention contains a cationic surfactant. The content of the cationic surfactant in the inorganic fine particle dispersion vehicle composition of the present invention is 1 × 10¹⁶ parts by weight of the polyvinyl acetal resin. -6 Preferably, it is 10 × 10 -6It is more preferable that it be greater than or equal to the weight, 10000 × 10 -6 It is preferable that the weight is less than or equal to 2500 × 10 -6 It is more preferable that the amount be less than or equal to parts by weight.

[0052] The inorganic fine particle dispersion vehicle composition of the present invention contains an organic solvent. The above organic solvents are not particularly limited, but examples include ethanol, isopropanol, butanol, toluene, xylene, N-methyl-2-pyrrolidone, acetone, ethyl acetate, butyl acetate, pentyl acetate, hexyl acetate, ethyl butyrate, butyl butyrate, pentyl butyrate, hexyl butyrate, methyl isobutyl ketone, methyl ethyl ketone, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, butyl carbitol, butyl carbitol acetate, terpineol, terpineol acetate, dihydroterpineol, dihydroterpineol acetate, texanol, isophorone, butyl lactate, dioctyl phthalate, dioctyl adipate, benzyl alcohol, phenylpropylene glycol, cresol, and the like. These organic solvents may be used individually or in combination of two or more.

[0053] The boiling point of the above organic solvent is preferably 70°C or higher. If the boiling point is 70°C or higher, evaporation will not be too rapid, resulting in a product with excellent handling properties. Furthermore, the boiling point is more preferably 90°C or higher, and more preferably 230°C or lower. By setting the range as described above, the strength of the resulting sheet can be improved.

[0054] The content of the organic solvent in the above inorganic fine particle dispersion vehicle composition is preferably 40% by weight or more, more preferably 50% by weight or more, preferably 95% by weight or less, and more preferably 90% by weight or less.

[0055] The method for preparing the above-mentioned inorganic fine particle dispersion vehicle composition is not particularly limited, and specifically, examples include a method of stirring and mixing the polyvinyl acetal resin composition of the present invention and an organic solvent by a conventionally known method.

[0056] Furthermore, an inorganic fine particle dispersion slurry composition can be prepared using the inorganic fine particle dispersion vehicle composition, inorganic fine particles, and plasticizer of the present invention, which contain the polyvinyl acetal resin composition and organic solvent of the present invention. Additionally, an organic solvent may be added as needed. The present invention also includes an inorganic microparticle dispersion vehicle composition, inorganic microparticles, and an inorganic microparticle dispersion slurry composition containing a plasticizer.

[0057] The content of the polyvinyl acetal resin in the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, but is preferably 2% by weight or more, more preferably 3% by weight or more, preferably 30% by weight or less, and more preferably 12% by weight or less. By keeping the content of the polyvinyl acetal resin within the above range, the amount of residue after firing can be reduced.

[0058] The inorganic fine particle dispersion slurry composition of the present invention contains a cationic surfactant. The content of cationic surfactant in the inorganic fine particle dispersion slurry composition of the present invention is 1 × 10⁶ per 100 parts by weight of the polyvinyl acetal resin. -6 Preferably, it is 10 × 10 -6 It is more preferable that it be greater than or equal to the weight, 10000 × 10 -6 It is preferable that the weight is less than or equal to 2500 × 10 -6 It is more preferable that the amount be less than or equal to parts by weight.

[0059] The inorganic fine particle dispersion slurry composition of the present invention contains the above-mentioned organic solvent. The content of the organic solvent in the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more, preferably 60% by weight or less, and more preferably 55% by weight or less. By keeping the above range, coating properties and the dispersibility of inorganic fine particles can be improved.

[0060] The inorganic fine particle dispersion slurry composition of the present invention contains inorganic fine particles. The inorganic fine particles mentioned above are not particularly limited and include, for example, ceramic powder, glass powder, metal fine particles, etc.

[0061] The ceramic powders mentioned above are not particularly limited and include powders of metal or nonmetal oxides, carbides, nitrides, borides, or sulfides 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, and Ni. These ceramic powders may be used individually or as a mixture of two or more types. Examples include barium titanate, aluminum nitride (AlN), silicon nitride (Si3N4), silicon carbide (SiC), alumina (Al2O3), copper oxide (CuO), and spinel compounds, ferrite, zirconia, zircon, barium zirconate, calcium zirconate, titanium oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead zirconate titanate, alumina nitride, silicon nitride, boron nitride, boron carbide, barium stinate, calcium stinate, magnesium silicate, mullite, steatite, cordierite, forsterite, and the like.

[0062] The above-mentioned glass powder is not particularly limited and includes, for example, glass powders such as bismuth oxide glass, silicate glass, lead glass, zinc glass, and boron glass, as well as glass powders of various silicon oxides such as CaO-Al2O3-SiO2 system, MgO-Al2O3-SiO2 system, and LiO2-Al2O3-SiO2 system. Furthermore, the above glass powders include SnO-B2O3-P2O5-Al2O3 mixture, PbO-B2O3-SiO2 mixture, BaO-ZnO-B2O3-SiO2 mixture, ZnO-Bi2O3-B2O3-SiO2 mixture, Bi2O3-B2O3-BaO-CuO mixture, Bi2O3-ZnO-B2O3-Al2O3-SrO mixture, ZnO-Bi2O3-B2O3 mixture, Bi2O3-SiO2 mixture, P2O5-Na2O-CaO-BaO-Al2O3-B2O3 mixture, P2O5-SnO mixture, P2O5-SnO-B2O3 mixture, P2 Other mixtures such as O5-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. can also be used. Note that R is an element selected from 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, BaO-ZnO-B2O3-SiO2 mixtures, or ZnO-Bi2O3-B2O3-SiO2 mixtures are preferred.

[0063] The above-mentioned metal nanoparticles are not particularly limited and include, for example, powders made of copper, nickel, palladium, iron, platinum, gold, silver, aluminum, tungsten, and alloys thereof. In addition to metal complexes, various carbon blacks, carbon nanotubes, etc., may also be used. Furthermore, ITO, FTO, niobium oxide, vanadium oxide, tungsten oxide, lanthanum strontium manganite, lanthanum strontium cobalt ferrite, yttrium-stabilized zirconia, gadolinium-doped ceria, nickel oxide, lanthanum chromite, etc., can also be used.

[0064] The content of inorganic fine particles in the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more, preferably 90% by weight or less, and more preferably 85% by weight or less. By setting it within the above range, it is possible to obtain a slurry composition that has sufficient viscosity and excellent coating properties, as well as excellent dispersibility of inorganic fine particles.

[0065] The inorganic fine particle dispersion slurry composition of the present invention contains a plasticizer. Examples of the above-mentioned plasticizers include monomethyl adipate, di(butoxyethyl) adipate, dibutoxyethoxyethyl adipate, triethylene glycol bis(2-ethylhexanoate), triethylene glycol dihexanoate, triethyl acetyl citrate, tributyl cetyl citrate, dibutyl sebacate, butylated benzyl phthalate, diisononyl adipate, diisodecyl phthalate, trippropionine, pentaerythritol tetraacetate, di-2-ethylhexyl phthalate, triacetin, and the like. Among these, triethylene glycol bis(2-ethylhexanoate), butylated benzyl phthalate, diisononyl adipate, diisodecyl phthalate, trippropionine, pentaerythritol tetraacetate, and di-2-ethylhexyl phthalate are preferred.

[0066] The boiling point of the plasticizer is preferably 240°C or higher, and preferably less than 390°C. Setting the boiling point to 240°C or higher facilitates evaporation during the drying process, preventing residue in the molded article. Setting it below 390°C prevents the generation of residual carbon. Note that the boiling point refers to the boiling point at atmospheric pressure.

[0067] The content of the plasticizer in the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, but is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, preferably 3% by weight or less, and more preferably 2.5% by weight or less. By keeping it within the above range, the amount of calcined residue of the plasticizer can be reduced.

[0068] The viscosity of the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, but it is preferably 0.1 Pa·s or higher, and preferably 100 Pa·s or lower, when measured at 20°C using a B-type viscometer with a probe rotation speed of 5 rpm. By setting the viscosity to 0.1 Pa·s or higher, the inorganic fine particle dispersion sheet obtained after coating by die coating printing or the like can maintain a predetermined shape. Furthermore, by setting the viscosity to 100 Pa·s or lower, problems such as the die coating marks not disappearing can be prevented, resulting in excellent printability.

[0069] The method for preparing the inorganic fine particle dispersion slurry composition of the present invention is not particularly limited, and conventionally known stirring methods can be used. Specifically, examples include stirring the polyvinyl acetal resin composition of the present invention, the inorganic fine particles, an organic solvent, a plasticizer, and other components added as needed using a bead mill or the like.

[0070] An inorganic fine particle dispersion sheet can be manufactured by coating the inorganic fine particle dispersion slurry composition of the present invention onto a support film that has been treated with a single-sided release agent, drying the organic solvent, and forming it into a sheet. The inorganic fine particle dispersion sheet described above is preferably 0.5 μm or thicker, and preferably 3 μm or less.

[0071] The support film used in manufacturing the above-mentioned inorganic fine particle dispersion sheet is preferably a resin film that is heat-resistant, solvent-resistant, and flexible. The flexibility of the support film allows the inorganic fine particle dispersion slurry composition to be applied to its surface using a roll coater, blade coater, etc., and the resulting inorganic fine particle dispersion sheet-forming film can be stored and supplied in a roll-like state.

[0072] Examples of resins used to form the support film include polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, polyvinyl chloride, polyfluoroethylene and other fluororesins, nylon, cellulose, and the like. The thickness of the above-mentioned support film is preferably 20 μm or more, and preferably 100 μm or less. Furthermore, it is preferable that the surface of the support film be treated with a release agent, which facilitates the peeling operation of the support film during the transfer process.

[0073] Furthermore, by using the inorganic fine particle dispersion slurry composition and inorganic fine particle dispersion sheet of the present invention in a dielectric green sheet and electrode paste, a multilayer ceramic capacitor can be manufactured. A multilayer ceramic capacitor using the inorganic fine particle dispersion slurry composition of the present invention is also one of the present inventions.

[0074] The manufacturing method for the above-described multilayer ceramic capacitor preferably includes the steps of printing a conductive paste onto the inorganic fine particle dispersion sheet of the present invention, drying it to produce a dielectric sheet, and laminating the dielectric sheets.

[0075] The conductive paste described above contains conductive powder. The material of the conductive powder described above is not particularly limited as long as it is a conductive material, and examples include nickel, palladium, platinum, gold, silver, copper, and alloys thereof. These conductive powders may be used individually or in combination of two or more types.

[0076] The binder resin and organic solvent used in the conductive paste described above can be the same as those used in the inorganic fine particle dispersion slurry composition of the present invention.

[0077] The method for printing the conductive paste described above is not particularly limited and includes, for example, screen printing, die-coating, offset printing, gravure printing, and inkjet printing.

[0078] In the above-described method for manufacturing multilayer ceramic capacitors, a multilayer ceramic capacitor is obtained by stacking dielectric sheets printed with the conductive paste, degreasing and firing, and then installing external electrodes. [Effects of the Invention]

[0079] According to the present invention, it is possible to provide a polyvinyl acetal resin composition that has high solubility in organic solvents and produces few fine undissolved particles when dissolved in organic solvents. Furthermore, it is possible to provide a polyvinyl acetal resin composition that has excellent handling properties when producing inorganic fine particle dispersion sheets, excellent decomposition properties at low temperatures, and is less prone to generating oxygen defects originating from undissolved particles, making it possible to manufacture ceramic laminates with excellent properties. In addition, it is possible to provide an inorganic fine particle dispersion vehicle composition containing the polyvinyl acetal resin composition, an inorganic fine particle dispersion slurry composition, and a laminated ceramic capacitor using the inorganic fine particle dispersion slurry composition. [Modes for carrying out the invention]

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0081] (Example 1) (1) Preparation of polyvinyl acetal resin composition 200 parts by weight of polyvinyl alcohol resin (degree of polymerization 1500, degree of saponification 99.9 mol%) was added to 3050 parts by weight of pure water, and the mixture was stirred at 90°C for approximately 2 hours to dissolve it and obtain an aqueous solution of polyvinyl alcohol resin. The obtained aqueous solution was cooled to room temperature, and 15 parts by weight of p-toluenesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) as an acid catalyst, 1200 parts by weight of n-butyraldehyde, and 25 parts by weight of an anionic surfactant were added. The mixture was emulsified with a high-speed stirrer to form micelles of polyvinyl alcohol resin, anionic surfactant, acid catalyst, and aldehyde. Subsequently, the liquid temperature was raised to 37°C and maintained at this temperature to carry out the acetalization reaction and precipitate the reaction product. After that, the mixture was maintained for a further 3 hours to complete the reaction, and then 1 part by weight of a cationic surfactant was added. Subsequently, neutralization, washing with water, and drying were carried out by conventional methods to obtain a polyvinyl acetal resin composition. Furthermore, NS-1 (sodium dodecyl sulfate, manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the anionic surfactant. In addition, CS-1 (n-octylammonium bromide (aliphatic amine salt), manufactured by Tokyo Chemical Industry Co., Ltd., solubility in ethanol 0.001 g / 100 g) was used as the cationic surfactant.

[0082] (2) Preparation of vehicle composition for dispersing inorganic fine particles To the obtained polyvinyl acetal resin composition, a mixed solvent of ethanol and toluene (weight ratio 1:1, boiling point 100°C) was added in a ratio of 1:900 parts by weight per 100 parts by weight of the polyvinyl acetal resin, and the mixture was stirred until homogeneous to obtain an inorganic fine particle dispersion vehicle composition.

[0083] (3) Preparation of inorganic fine particle dispersion slurry composition To the obtained inorganic microparticle dispersion vehicle composition, barium titanate ("BT-02", manufactured by Sakai Chemical Industry Co., Ltd., average particle size 0.2 μm) was added as inorganic microparticles, PL-1 (triethylene glycol bis(2-ethylhexanoate)) as a plasticizer, and a mixed solvent of ethanol and toluene (weight ratio 1:1) as an organic solvent, in the proportions shown in Table 2. Dispersion treatment was performed using a bead mill to obtain an inorganic microparticle dispersion slurry composition.

[0084] (Examples 2-13, Comparative Examples 1-11) A polyvinyl acetal resin composition was obtained in the same manner as in Example 1, except that the types and amounts of polyvinyl alcohol resin, anionic surfactant, and cationic surfactant, as well as the amounts of water, aldehyde, and acid catalyst added, were as shown in Table 1. Furthermore, an inorganic fine particle dispersion slurry composition was obtained in the same manner as in Example 1, except that the type of plasticizer was as shown in Table 2, using the obtained polyvinyl acetal resin composition. The following cationic surfactants, anionic surfactants, and plasticizers were used. <Cationic surfactants> CS-2: Dodecylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., aliphatic amine salt, solubility in ethanol 0.002g / 100g) CS-3: Tributyldodecylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., phosphonium salt, solubility in ethanol 0.001g / 100g) CS-4: (2-carboxyethyl)triphenylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., phosphonium salt, solubility in ethanol 0.001g / 100g) CS-5: Hexadecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., quaternary ammonium salt, solubility in ethanol 0.004g / 100g) CS-6: Tetraethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., quaternary ammonium salt, solubility in ethanol 0.002g / 100g) CS-7: 1-ethyl-3-methylimidazolium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., heterocyclic amine salt, solubility in ethanol 0.005g / 100g) CS-8: Cetylpyridinium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., heterocyclic amine salt, solubility in ethanol 0.006 g / 100 g) CS-9: Dodecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., quaternary ammonium salt, solubility in ethanol 0.006g / 100g) CS-10: Benzethonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., aromatic amine salt, solubility in ethanol 0.005g / 100g) CS-11: Tetrabutylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., quaternary ammonium salt, solubility in ethanol 0.026 g / 100 g) CS-12: Tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., quaternary ammonium salt, solubility in ethanol: 0.35 g / 100 g) CS-13: Dodecane-1-yl(ethyl)(dimethyl)ammonium ethyl sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., quaternary ammonium salt, solubility in ethanol 0.5g / 100g) <Anionic surfactants> NS-2: Sodium dodecylbenzenesulfonate, manufactured by Tokyo Chemical Industry Co., Ltd. <Plasticizer> PL-2: Benzyl butylated phthalate, manufactured by Tokyo Chemical Industry Co., Ltd. PL-3: Diisononyl adipate, manufactured by Tokyo Chemical Industry Co., Ltd. PL-4: Diisodecyl phthalate, manufactured by Tokyo Chemical Industry Co., Ltd. PL-5: Trippropionine, manufactured by Tokyo Chemical Industry Co., Ltd. PL-6: Pentaerythritol tetraacetate, manufactured by Tokyo Chemical Industry Co., Ltd. PL-7: Di-2-ethylhexyl phthalate, manufactured by Tokyo Chemical Industry Co., Ltd.

[0085] <Rating> The polyvinyl acetal resin, polyvinyl acetal resin composition, and inorganic fine particle dispersion slurry composition obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 2 and 3.

[0086] (1) Polyvinyl acetal resin (1-1) Hydroxyl group, acetal group, acetyl group The obtained polyvinyl acetal resin is dissolved in DMSO-D6 at a concentration of 10% by weight. 13 The amount of hydroxyl groups, acetal groups, and acetyl groups was measured using 1C-NMR.

[0087] (1-2)Molecular weight The obtained polyvinyl acetal resin was measured by gel permeation chromatography using TSKgel SuperHZM-H as the column, determining the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) in terms of polystyrene equivalent.

[0088] (1-3) Particle size The obtained polyvinyl acetal resin was observed using a scanning electron microscope (Hitachi High-Technologies Corporation's "Regulus8220"), and the maximum Ferret diameter of 100 primary particles was measured. The primary particle diameter and CV value were then determined by calculating the average value. Furthermore, the secondary particle size of the obtained polyvinyl acetal resin particles was measured using a laser diffraction scattering particle size distribution analyzer (Mastersizer3000), and the particle sizes were determined by setting the volume-based cumulative particle sizes at 10%, 50%, and 90% from the smallest particle size side as D10, D50, and D90, respectively. The particle size distribution ε[(D90-D10) / D50] was also calculated from the measured D10, D50, and D90.

[0089] (2) Polyvinyl acetal resin composition The content of cationic surfactants, anionic surfactants, p-toluenesulfonic acid, or their salts was confirmed by DART-MS (direct ionization mass spectrometry) using DART-OS (manufactured by AMR Corporation).

[0090] (3) Particles The obtained polyvinyl acetal resin composition was diluted with a mixed solvent of ethanol and toluene (weight ratio 1:1) so that the resin content was 2% by weight. The particle size distribution of the polyvinyl acetal resin in 10 mL of this solution was measured using a particle counter ("KL-11A", manufactured by Rion Co., Ltd.). The number of particles with a diameter of 0.5 to 1.0 μm per 1 mL of solution was confirmed. In addition, the volume of particles with a diameter of 0.5 to 1.0 μm was calculated assuming they were perfect spheres with a diameter of 0.75 μm, and the percentage (volume %) of particles with a diameter of 0.5 to 1.0 μm was calculated based on the obtained measurement results.

[0091] (4) Dissolution time 192 g of a mixed solvent of ethanol and toluene (weight ratio 1:1) was placed in a 500 mL beaker. The temperature was maintained at 25°C, and while stirring with two impellers at a rotation speed of 200 rpm, 48.0 g (concentration 20% by weight) of the obtained polyvinyl acetal resin composition was added and dissolved. The dissolution time, from the addition of the obtained polyvinyl acetal resin composition until the insoluble resin disappeared, was measured by visual observation and evaluated according to the following criteria. A: 120 minutes or more but less than 160 minutes B: 160 minutes or more but less than 220 minutes C: 220 minutes or more, less than 550 minutes D: 550 minutes or more

[0092] (5) Performance evaluation of multilayer ceramic capacitors (MLCCs) (Preparation of a green sheet) A ceramic green sheet was prepared by coating a release-treated polyethylene terephthalate (PET) film with the obtained slurry composition to a dry film thickness of 1 μm and then drying it.

[0093] Using the obtained ceramic green sheets, a raw laminate was formed. Specifically, a conductive paste mainly composed of Ni was screen printed onto the ceramic green sheet to form a conductive paste film that would serve as the internal electrode. Then, multiple ceramic green sheets with the conductive paste film formed on them were stacked so that the sides with the drawn-out conductive paste film were alternating, and then pressed together to obtain a raw laminate. Next, the raw laminate was fired. Specifically, it was first heated to 500°C under a reducing atmosphere to burn off the binder. After that, the oxygen partial pressure was reduced to 10 -10 The material was fired at 1250°C for 3 hours in a reducing atmosphere consisting of H2-N2-H2O gas at MPa. Subsequently, a conductive paste consisting of silver, terpineol, and ethylcellulose was prepared. The conductive paste was applied to the fired body obtained using the dip method, and the material was fired at 1250°C for 3 hours to fabricate a multilayer ceramic capacitor.

[0094] (5-1) Number of voids in the dielectric layer The cross-section of the dielectric layer of the obtained multilayer ceramic capacitor was observed using a scanning electron microscope (SEM). The sinterability was evaluated according to the following criteria. A: No voids caused by insoluble resin lumps were observed. B: One to five voids caused by insoluble resin lumps were observed. C: Between 5 and 10 voids caused by insoluble resin lumps were observed. D: More than 10 voids caused by insoluble resin lumps were observed.

[0095] (5-2) Equivalent series resistance (ESR) Ten multilayer ceramic capacitors were fabricated using the method described above. These capacitors were then heat-treated at 150°C for 1 hour in an air atmosphere. After that, they were mounted on a measurement board, and 24 ± 2 hours after the completion of the heat treatment, the equivalent series resistance (ESR) was measured using a network analyzer. The measurement frequency was 10 MHz. Finally, the values ​​for all 10 capacitors (for each condition) were averaged, and those with an ESR of less than 48 mΩ were classified as good (○), and those with an ESR of 48 mΩ or more were classified as poor (×).

[0096] [Table 1]

[0097] [Table 2]

[0098] [Table 3] [Industrial applicability]

[0099] According to the present invention, it is possible to provide a polyvinyl acetal resin composition that has high solubility in organic solvents and produces few fine undissolved particles when dissolved in organic solvents. Furthermore, it is possible to provide a polyvinyl acetal resin composition that is less prone to the generation of oxygen defects originating from undissolved particles and that enables the production of ceramic laminates with excellent properties. In addition, it is possible to provide an inorganic fine particle dispersion vehicle composition containing the polyvinyl acetal resin composition, an inorganic fine particle dispersion slurry composition, and a laminated ceramic capacitor using the inorganic fine particle dispersion slurry composition.

Claims

1. A composition containing polyvinyl acetal resin and cationic surfactant, The polyvinyl acetal resin has a primary particle size of 0.01 μm or more and 10 μm or less, a degree of polymerization of 300 or more and 8000 or less, a hydroxyl group content of 18.0 mol% or more and 40.0 mol% or less, and an acetal group content of 45.0 mol% or more and 80.0 mol% or less. The cationic surfactant is added in a concentration of 1 × 10⁻¹⁶ per 100 parts by weight of the polyvinyl acetal resin. －６ Weight part or more 10,000×10 －６ A polyvinyl acetal resin composition containing less than or equal to parts by weight.

2. The polyvinyl acetal resin composition according to claim 1, wherein the polyvinyl acetal resin has a degree of polymerization of 1500 to 2000, a hydroxyl group content of 25.0 mol% to 35.0 mol%, an acetal group content of 60.0 mol% to 70.0 mol%, and an acetyl group content of 0.1 mol% to 0.5 mol%.

3. The polyvinyl acetal resin composition according to claim 1 or 2, wherein the cationic surfactant has a solubility in ethanol of 0.001 g / 100 g or more.

4. Add 1 x 10⁻¹⁶ p-toluenesulfonic acid or its salt per 100 parts by weight of polyvinyl acetal resin. －６ Weight part or more 500 x 10 －６ A polyvinyl acetal resin composition according to claim 1 or 2, containing in amounts by weight or less.

5. The polyvinyl acetal resin composition according to claim 1 or 2, wherein the secondary particle size is measured by laser diffraction scattering particle size distribution measurement, and when the particle sizes at 10%, 50%, and 90% of the volume-based cumulative total from the smallest particle size side are defined as D10, D50, and D90, respectively, (D90 - D10) / D50 is 0.7 or more and 1.5 or less.

6. The polyvinyl acetal resin composition according to claim 1 or 2, wherein the polyvinyl acetal resin has a molecular weight distribution (Mw / Mn), which is the ratio of weight-average molecular weight Mw to number-average molecular weight Mn, of 1.8 or more and 2.6 or less.

7. A polyvinyl acetal resin composition according to claim 1 or 2, and an inorganic fine particle dispersion vehicle composition containing an organic solvent.

8. An inorganic fine particle dispersion slurry composition comprising the inorganic fine particle dispersion vehicle composition according to claim 7, inorganic fine particles, and a plasticizer.

9. A multilayer ceramic capacitor comprising the inorganic fine particle dispersion slurry composition described in claim 8.

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