JP2013249429A - Ceramic paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic paste capable of largely improving dispersibility of a ceramic powder, and having a high strength and an excellent adherence.SOLUTION: A ceramic paste contains a ceramic powder, a resin component, an ester compound having a structure represented by formula (1) and having at least one hydroxyl group in the molecule, and a solvent. In the formula, Rand Rare a structural unit having C, H or O.

Description

The present invention relates to a ceramic paste capable of greatly improving the dispersibility of ceramic powder and having high strength and excellent adhesion.

A multilayer electronic component such as a multilayer ceramic capacitor is generally manufactured through the following steps as disclosed in Patent Document 1 or Patent Document 2.
First, after adding a plasticizer, a dispersant, etc. to a solution in which a binder resin such as polyvinyl butyral resin or poly (meth) acrylate ester resin is dissolved in an organic solvent, ceramic raw material powder is added, and uniformized by a ball mill or the like. A ceramic slurry composition having a constant viscosity is obtained by mixing and defoaming. The obtained ceramic slurry composition is cast on a support surface such as a polyethylene terephthalate film or SUS plate that has been subjected to mold release treatment using a doctor blade, reverse roll coater, etc., and volatile components such as organic solvents are collected by heating or the like. After leaving, the ceramic green sheet is obtained by peeling from the support.

Next, an electrode layer paste containing a conductive material such as palladium, silver, or nickel is printed in a predetermined pattern on the obtained ceramic green sheet. A plurality of the printed ceramic green sheets obtained are stacked and laminated, and a ceramic green chip is obtained through a press cutting process. And the process of forming an external electrode on the end face etc. of the ceramic fired product obtained by performing the process of thermally decomposing and removing the binder component contained in the obtained ceramic green chip, so-called degreasing process, etc. To manufacture laminated electronic components.

In recent years, with the increase in capacity of multilayer ceramic capacitors, the conductive layers and dielectric layers have been made thinner, and multilayer ceramic capacitors having a thickness of 1 μm or less for both the conductive layers and dielectric layers have been manufactured. In recent years, when pressure is applied to such a thin layer sheet, the ceramic paste is printed by filling the gaps in the electrode print pattern so that pressure is concentrated on the electrode print pattern and the conductive paste does not break through the dielectric layer and cause a short circuit. The construction method is generally used.
However, with the recent thinning of the layer, the powder used in the ceramic paste has also become smaller in particle size, and due to poor dispersion of the inorganic powder in the ceramic paste, the paste has insufficient fluidity and cannot form a uniform pattern. Problems have arisen.
In addition, when a conventional ceramic paste is used, the strength after drying becomes insufficient, so that it may be hung during press cutting, or the adhesion with the electrode may be reduced and the ceramic may be peeled off from the electrode during cutting. Also occurred.

On the other hand, Patent Document 3 discloses a dispersion process using three rolls in order to obtain a ceramic paste having excellent dispersibility. However, the energy required for the dispersion is sufficient only by such a dispersion process. Even in such a case, it is difficult to obtain sufficient dispersibility because the surface of the ceramic cannot be wetted with the solvent.
Patent Document 4 describes a method of suppressing peeling at the time of press cutting by adding an organometallic compound to a ceramic paste and improving an adhesive force with an electrode part. Then, there existed a subject that sufficient dispersibility was not obtained as a result of the viscosity of a paste becoming high.

Japanese Patent Publication No. 3-35762 Japanese Patent Publication No. 4-49766 JP-A-3-74820 Japanese Patent Laid-Open No. 2002-313671

An object of the present invention is to provide a ceramic paste capable of greatly improving the dispersibility of ceramic powder and having high strength and excellent adhesiveness.

Ｒ^１及びＲ^２はＣ、Ｈ又はＯを有する構造単位を表す。
以下に本発明を詳述する。 The present invention is a ceramic paste containing a ceramic powder, a resin component, an ester compound having a structure represented by the following formula (1) and having one or more hydroxyl groups in the molecule and a solvent.

R ¹ and R ² represent a structural unit having C, H or O.
The present invention is described in detail below.

In the ceramic paste containing the ceramic powder, the ester compound, the resin component and the solvent, the present inventors can significantly improve the dispersibility of the ceramic powder by using an ester compound having a predetermined structural unit, In addition, the present inventors have found that a ceramic paste capable of realizing high strength and excellent adhesiveness can be obtained, thereby completing the present invention.

The ceramic paste according to the present invention contains a ceramic powder.
The ceramic powder is not particularly limited. For example, a powder made of alumina, zirconia, aluminum silicate, titanium oxide, zinc oxide, barium titanate, magnesia, sialon, spinemullite, silicon carbide, silicon nitride, aluminum nitride, or the like. Is mentioned. Especially, it is preferable to consist of the same component as the ceramic powder contained in the ceramic green sheet to be used. These ceramic powders may be used alone or in combination of two or more.

The ceramic powder is preferably in the form of fine particles, and particularly preferably has a fine particle size. The average particle size of the ceramic powder is preferably 5 μm or less.

The amount of the ceramic powder added is preferably 100 to 10,000 parts by weight with respect to 100 parts by weight of the resin component. If the content of the ceramic powder is less than 100 parts by weight, the residue may increase when the green sheet is sintered, and the electrical characteristics may be deteriorated. The content of the ceramic powder is 10000 parts by weight. If it exceeds, the amount of the resin component adsorbed with respect to the amount of the ceramic powder is small, so that sufficient dispersion cannot be achieved, and the slurry becomes non-uniform and agglomerates to deteriorate the electrical characteristics of the sheet. A preferable lower limit of the amount of the ceramic powder added is 250 parts by weight, and a preferable upper limit is 3500 parts by weight.

Ｒ^１及びＲ^２はＣ、Ｈ又はＯを有する構造単位を表す。 The ceramic paste of this invention has the structure shown to following formula (1), and contains the ester compound which has a 1 or more hydroxyl group in a molecule | numerator.

R ¹ and R ² represent a structural unit having C, H or O.

By containing the ester compound, the thickening effect of the ceramic paste due to cross-linking of the ceramic powder and the resin component can be suppressed.

The ester compound is a structural unit in which R ¹ and R ² have C, H, or O. Moreover, it has one or more hydroxyl groups in the molecule. Thereby, ceramic powder and a hydroxyl group exert an attractive interaction, an ester compound adsorb | sucks to a ceramic powder, and can improve dispersibility.
Furthermore, the ester compound may have a carboxyl group.

R ¹ or R ² of the ester compound is preferably a structural unit having 8 or more carbon atoms. When the number of carbon atoms is 7 or less, the bulk of the ester compound is not sufficient, and the distance between the ceramic powders may be insufficient. The more preferable lower limit of the carbon number is 10, and the preferable upper limit is 50.
R ¹ and R ² are preferably linear.

As the R ¹ and R ^2, it is preferable to use the total number of hydroxyl groups is 2 or more. Thereby, the number of functional groups increases, and it becomes easier to crosslink with the ceramic powder. Preferably, the total number of hydroxyl groups is 3 or more.

The ester compound is not particularly limited as long as it has the structure of the above formula (1), but glyceryl monooleate, methyl-9,10-dihydroxyoctadecanoate, glyceryl monostearate, caprylin, glyceryl mono Examples include myristate, methyl-12-hydroxystearate, ethyl 3-hydroxyhexanoate, sorbitan monolaurate, propylene glycol monostearate, glycerol monoisostearate, ethylene glycol monostearate, 2-linoleoylglycerol, etc. It is done.
Among these, glyceryl monooleate is particularly preferable.

The content of the ester compound is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the ceramic powder. If the content of the ceramic powder is less than 0.01 parts by weight, the amount of the ester compound that crosslinks with the ceramic powder is insufficient, and the resin component and the ceramic powder cannot be prevented from being cross-linked, resulting in thickening. Sometimes. If the content of the ester compound exceeds 20 parts by weight, the excessively added ester compound also inhibits the adsorption of the ceramic powder and the resin component, so that the dispersibility is remarkably lowered and the electrical properties of the sheet are adversely affected. There is. More preferably, it is 0.1 to 2 parts by weight.

The ester compound preferably has 4 or less carbon atoms between the hydroxyl group and the carbonyl group. Thereby, when the carbonyl group approaches the ceramic powder, the probability that the hydroxyl group in the vicinity of the carbonyl group is adsorbed on the ceramic surface increases, and the dispersibility can be improved.

When a plurality of hydroxyl groups are present in the ester compound, the number of carbon atoms between the hydroxyl groups is preferably 4 or less. Thereby, when one of the hydroxyl groups approaches the ceramic powder, the probability that the hydroxyl groups near the ceramic powder are adsorbed on the ceramic surface is increased, and the dispersibility can be improved.

The conductive paste of the present invention contains a resin component.
As said resin component, it is preferable to contain the polyvinyl acetal resin A whose polymerization degree is 20-400 and whose amount of hydroxyl groups is 20-30 mol%. Thereby, the ceramic powder can be finely dispersed. Moreover, aggregation of the ceramic powder due to crosslinking when the resin component is added can be prevented.
The resin component preferably further contains a polyvinyl acetal resin B having a degree of polymerization of 450 to 4000 and a hydroxyl group content of 20 to 30 mol%. Thereby, it can be sufficiently dissolved in the solvent and can be adsorbed on the surface of the ceramic powder.
In particular, when “polyvinyl acetal resin A” and “polyvinyl acetal resin B” are not distinguished from each other, they are simply referred to as “polyvinyl acetal resin”.

The polyvinyl acetal resin A has a preferable lower limit of 20 and a preferable upper limit of 400 for the degree of polymerization. If the degree of polymerization is less than 20, problems such as a decrease in strength of the formed green sheet may occur. When the degree of polymerization exceeds 400, the viscosity of the ceramic paste increases and the dispersion stability decreases due to aggregation, which may adversely affect the electrical characteristics of the green sheet after sintering. A more preferred lower limit is 150, and a more preferred upper limit is 350.

In the ceramic paste of the present invention, the polyvinyl acetal resin A has a preferable lower limit of 0.01 part by weight and a preferable upper limit of 10 parts by weight with respect to 100 parts by weight of the ceramic powder. If the content of the polyvinyl acetal resin A is less than 0.01 parts by weight, the amount of the resin adsorbed with respect to the amount of the ceramic powder is small, so that sufficient dispersion cannot be achieved, and the slurry becomes non-uniform and aggregates to form a sheet The electrical characteristics may be deteriorated. When content of the said polyvinyl acetal resin A exceeds 10 weight part, when a green sheet is sintered, a residue will increase and an electrical property may deteriorate. A more preferred lower limit is 5 parts by weight, and a more preferred upper limit is 8 parts by weight.

The polyvinyl acetal resin B has a preferred lower limit of the polymerization degree of 450 and a preferred upper limit of 4000. When the polymerization degree is less than 450, the viscosity becomes too low and the print pattern may be blurred. When the said polymerization degree exceeds 4000, a viscosity will become high too much and a dispersibility may become inadequate. A more preferred lower limit is 800, and a more preferred upper limit is 2000.

In the conductive paste of the present invention, the polyvinyl acetal resin B has a preferable lower limit of 1 part by weight and a preferable upper limit of 20 parts by weight with respect to 100 parts by weight of the total amount of the conductive powder and the ceramic powder. If the content of the polyvinyl acetal resin B is less than 1 part by weight, the adhesiveness may be insufficient. When the content of the polyvinyl acetal resin B exceeds 20 parts by weight, the residue may increase when sintered. A more preferred lower limit is 4 parts by weight, and a more preferred upper limit is 12 parts by weight.

The minimum with the preferable amount of hydroxyl groups of the said polyvinyl acetal resin is 20 mol%, and a preferable upper limit is 30 mol%. If the amount of the hydroxyl group is less than 20 mol%, the conductive powder is agglomerated, which may adversely affect the electrical characteristics of the conductive layer. If the amount of the hydroxyl group exceeds 30 mol%, the adhesive strength is reduced. May end up.

The polyvinyl acetal resin has a preferable lower limit of the acetalization degree of 70 mol% and a preferable upper limit of 80 mol%. If the degree of acetalization is less than 70 mol%, the solubility in a solvent is remarkably lowered and the slurry is agglomerated, which may adversely affect the electrical properties, and the degree of acetalization exceeds 80 mol%. The polyvinyl acetal resin may have a reduced adhesive strength.

In the polyvinyl acetal resin, the preferable lower limit of the acetyl unit content is 0.1 mol%, and the preferable upper limit is 25 mol%. When the above range is exceeded, the solubility of the raw material polyvinyl alcohol resin is lowered, and the acetalization reaction becomes difficult.
The polyvinyl acetal resin is preferably a polyvinyl acetal resin obtained by acetalizing a polyvinyl alcohol resin with an aldehyde.

The polyvinyl acetal resin may have a carboxylic acid-modified group. In that case, the upper limit with preferable content of ethylene modification group is 20 mol%. If it exceeds 20 mol%, the solubility in an organic solvent is lowered, so that the ceramic paste production may be hindered or the viscosity stability with time may be deteriorated.

The acetalization method is not particularly limited, and a conventionally known method can be used. For example, an aqueous solution of polyvinyl alcohol, an alcohol solution, a water / alcohol mixed solution, a dimethyl sulfoxide (DMSO) solution in the presence of an acid catalyst. Examples thereof include a method of adding various aldehydes.

The aldehyde used for the acetalization is not particularly limited. For example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, furfural, glyoxal, glutaraldehyde, benzaldehyde 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde and the like. Among them, it is preferable to use acetaldehyde and butyraldehyde alone or to use acetaldehyde and butyraldehyde in combination.

The acid catalyst is not particularly limited, and either an organic acid or an inorganic acid can be used. Examples thereof include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid.

In order to stop the acetalization reaction, neutralization with an alkali is preferably performed. It does not specifically limit as said alkali, For example, sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate, potassium hydrogencarbonate etc. are mentioned.
Moreover, it is preferable to wash | clean the polyvinyl acetal resin obtained using water etc. before and after the said neutralization process. In order to prevent impurities contained in the cleaning water from being mixed, it is more preferable to perform the cleaning with pure water.

The polyvinyl alcohol resin is preferably a polyvinyl alcohol resin obtained by saponifying a polymer of vinyl ester such as vinyl formate, vinyl acetate, vinyl propionate or vinyl pivalate. From the economical viewpoint, the vinyl ester is more preferably vinyl acetate.

The polyvinyl alcohol resin is also preferably a polyvinyl alcohol resin obtained by saponifying a copolymer of the vinyl ester and the α-olefin.
Examples of the α-olefin include ethylene, propylene, isopropylene, butylene, isobutylene, pentylene, hexylene, cyclohexylene, cyclohexylethylene, and cyclohexylpropylene. Of these, ethylene is preferable.
Further, as the polyvinyl alcohol resin, a terminal-modified polyvinyl alcohol resin obtained by copolymerizing the vinyl ester and ethylene in the presence of a thiol compound such as thiol acetic acid or mercaptopropionic acid, and then saponifying is then used. May be.

When the polyvinyl alcohol resin is copolymerized, the content of the α-olefin is preferably 1 mol% at a preferable lower limit and 20 mol% at a preferable upper limit. When the content of the α-olefin is less than 1 mol%, the effect of adding the α-olefin may not be obtained. When the content of the α-olefin exceeds 20 mol%, the solubility of the obtained polyvinyl alcohol resin in water decreases, making it difficult to perform the acetalization reaction, or the hydrophobicity of the obtained polyvinyl acetal resin. May become too strong and the solubility in organic solvents may decrease.

The polyvinyl alcohol resin is a polyvinyl alcohol resin obtained by copolymerizing other ethylenically unsaturated monomers in addition to the vinyl ester and the α-olefin within a range not impairing the effects of the present invention. There may be.
Examples of the other ethylenically unsaturated monomers include acrylic acid, methacrylic acid, (anhydrous) fumaric acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and trimethyl. -(3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, Examples include vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, and sodium allyl sulfonate.

When the polyvinyl alcohol resin is copolymerized, the content of the other ethylenically unsaturated monomers is preferably 1 mol% at the preferred lower limit and 30 mol% at the preferred upper limit. If the content of the other ethylenically unsaturated monomer is less than 1 mol%, the effect of adding the other ethylenically unsaturated monomer may not be obtained. When content of the said other ethylenically unsaturated monomer exceeds 30 mol%, properties, such as adhesiveness of a polyvinyl acetal resin obtained, coating-film strength, and thermal decomposability, may fall.

The polyvinyl alcohol resin has a preferred lower limit of the saponification degree of 80 mol%. If the degree of saponification is less than 80 mol%, the solubility of the resulting polyvinyl alcohol in water may be reduced, making it difficult to carry out the acetalization reaction. If the amount is small, it may be difficult to proceed with the acetalization reaction itself.

The polyvinyl alcohol resin has a preferable lower limit of 20 and a preferable upper limit of 4000. When the polymerization degree is less than 20, the viscosity is low and the printed pattern may be blurred. When the degree of polymerization exceeds 4000, the viscosity of the conductive paste increases, and the dispersion stability decreases due to aggregation, which may adversely affect the electrical characteristics of the green sheet after sintering.

Examples of the resin component may include an acrylic resin such as polymethyl methacrylate, a cellulose resin such as ethyl cellulose, and a resin such as polyethylene oxide.

If necessary, a plasticizer, an antioxidant, an ultraviolet absorber, a surfactant, a filler, etc. may be added to the ceramic paste of the present invention as appropriate. A small amount of resin may be added.

The ceramic paste of the present invention contains a solvent.
The solvent is not particularly limited, and examples thereof include ketone solvents, alcohol solvents, aromatic hydrocarbon solvents, ester solvents, cellosolve solvents, terpineol solvents, and acetate solvents.
The ketone solvent is not particularly limited, and examples thereof include acetone, methyl ethyl ketone, dipropyl ketone, and diisobutyl ketone.
The alcohol solvent is not particularly limited, and examples thereof include methanol, ethanol, isopropanol, butanol and the like.
The aromatic hydrocarbon solvent is not particularly limited, and examples thereof include toluene and xylene.
The ester solvent is not particularly limited. For example, methyl propionate, ethyl propionate, butyl propionate, methyl butanoate, ethyl butanoate, butyl butanoate, methyl pentanoate, ethyl pentanoate, butyl pentanoate, hexanoic acid Examples thereof include methyl, ethyl hexanoate, butyl hexanoate, 2-ethylhexyl acetate, and 2-ethylhexyl butyrate.
The cell solve solvent is not particularly limited, and examples thereof include methyl cell solve, ethyl cell solve, butyl cell solve and the like.

The terpineol solvent is not particularly limited, and examples thereof include α-terpineol.
The acetate solvent is not particularly limited, and examples thereof include dihydroterpinyl acetate, butyl cellosolve acetate, and butyl carbitol acetate.
In particular, since dihydroterpinyl acetate has low polarity, the carboxyl group in the carboxyl group-containing compound is not easily adapted to the solvent, the interaction with the powder is increased, and it can be adsorbed on the surface more efficiently.
These solvents may be used alone or in combination of two or more.

The method for producing the ceramic paste of the present invention is not particularly limited. For example, the ceramic powder, ester compound, resin component, solvent, and various additives to be added as necessary are ball mill, blender mill, three rolls. The method of mixing using various mixers, such as etc., is mentioned.

When producing the ceramic paste of the present invention, the above ceramic powder, ester compound, resin component and solvent are added and mixed to produce a ceramic dispersion, and the above resin component and solvent are added and mixed to produce a resin solution. It is preferable to use a method having a step of adding a resin solution to the ceramic dispersion.
Thus, by using a method of separately preparing and mixing the ceramic dispersion and the resin solution, it is possible to suppress the aggregation of the ceramic powder as compared with the method of mixing all at once, and accordingly, the polyvinyl acetal resin Can be prevented from agglomerating and lowering the dispersibility.
In addition, when using the method of producing and mixing a ceramic dispersion liquid and a resin solution separately, it is preferable to add the polyvinyl acetal resin A to the said ceramic dispersion liquid.

The ceramic paste of the present invention can be used as a raw material for a ceramic green sheet. When used in a step-absorbing ceramic paste for forming a step-absorbing layer having the same thickness (hereinafter also referred to as a step-absorbing paste), the internal electrode layer is not printed even when a high pressure is applied during lamination. Therefore, there is an advantage that damage to a portion where a step is generated from the dielectric layer can be prevented.

ADVANTAGE OF THE INVENTION According to this invention, the dispersibility of ceramic powder can be improved significantly, and the ceramic paste which has high intensity | strength and the outstanding adhesiveness can be provided.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited only to these examples.

(Synthesis of polyvinyl acetal resin (A))
280 parts by weight of polyvinyl alcohol having a degree of polymerization of 230 and a saponification degree of 99 mol% was added to 3000 parts by weight of pure water, and stirred at a temperature of 90 ° C. for about 2 hours for dissolution. This solution was cooled to 40 ° C., 340 parts by weight of hydrochloric acid having a concentration of 35% by weight, 200 parts by weight of n-butyraldehyde and 20 parts by weight of acetaldehyde were added thereto, and the liquid temperature was lowered to 1 ° C. to maintain this temperature. Then, an acetalization reaction was performed to precipitate a reaction product. Then, liquid temperature was hold | maintained at 25 degreeC for 3 hours, reaction was completed, and the white powder of the polyvinyl acetal resin (A) was obtained through neutralization, water washing, and drying by a conventional method. When the obtained polyvinyl acetal resin was dissolved in DMSO-d ₆ (dimethylsulfoxide) and the degree of butyralization was measured using ¹³ C-NMR (nuclear magnetic resonance spectrum), the degree of butyralization was 70 mol%. The degree of acetoacetalization was 7 mol%. This polyvinyl acetal resin (A) was designated as polyvinyl acetal resin (A1).
Further, polyvinyl acetal resins (A2) and (A3) were synthesized in the same manner as the polyvinyl acetal resin (A1) except that the raw materials and conditions shown in Table 1 were used.

(Synthesis of polyvinyl acetal resin (B))
280 parts by weight of polyvinyl alcohol having a polymerization degree of 1700, a saponification degree of 99 mol% and an ethylene modification degree of 4 mol% was added to 3000 parts by weight of pure water, and stirred at a temperature of 90 ° C. for about 2 hours for dissolution. The solution was cooled to 40 ° C., 340 parts by weight of hydrochloric acid having a concentration of 35% by weight and 210 parts by weight of n-butyraldehyde were added thereto, the liquid temperature was lowered to 10 ° C., and this temperature was maintained to carry out the acetalization reaction. And the reaction product was precipitated. Then, liquid temperature was hold | maintained at 40 degreeC for 3 hours, reaction was completed, and the white powder of the polyvinyl acetal resin (B) was obtained through neutralization, water washing, and drying by a conventional method. When the obtained polyvinyl acetal resin was dissolved in DMSO-d ₆ (dimethyl sulfoxide) and the degree of butyralization was measured using ¹³ C-NMR (nuclear magnetic resonance spectrum), the degree of butyralization was 77 mol%. there were. This polyvinyl acetal resin (B) was designated as polyvinyl acetal resin (B1).
Further, polyvinyl acetal resins (B2) and (B3) were synthesized in the same manner as the polyvinyl acetal resin (B1) except that the raw materials and conditions shown in Table 1 were used.

Example 1
(Preparation of ceramic dispersion)
0.25 parts by weight of the obtained polyvinyl acetal resin (A1) and 1 part by weight of glyceryl monooleate were added to 12 parts by weight of dihydroterpinyl acetate (DHTA) and dissolved by stirring. Subsequently, 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 with three rolls to prepare a ceramic dispersion.

(Preparation of resin solution)
A resin solution was prepared by adding 10 parts by weight of polyvinyl acetal resin (B1) to 100 parts by weight of dihydroterpinyl acetate (DHTA) and dissolving with stirring.

(Production of ceramic paste)
A resin paste was added to the obtained ceramic dispersion, and the mixture was stirred for 90 minutes with a three roll to obtain a ceramic paste.

(Examples 2 to 12, Comparative Examples 1 to 10)
A ceramic paste was produced in the same manner as in Example 1 except that the polyvinyl acetal resin and additives shown in Table 2 were used.

(1) Dispersibility evaluation (preparation of a dispersibility evaluation solution)
0.1 parts by weight of the obtained ceramic paste was added to 10 parts by weight of dihydroterpinyl acetate, and the mixture was stirred for 10 minutes with an ultrasonic disperser (US-303 manufactured by SND Co., Ltd.). Produced.

(Dispersibility evaluation)
The obtained dispersion evaluation solution was subjected to particle size distribution measurement using a laser diffraction particle size distribution analyzer (LA-910, manufactured by Horiba Ltd.), and the position of the maximum particle size peak and the average particle size were measured. The average particle size was evaluated according to the following criteria.

(Criteria)
◎ Less than 0.5μm ○ 0.5μm or more, less than 1.5μm △ 1.5μm or more, less than 2.5μm x 2.5μm or more

(2) Surface roughness (production of a sheet made of ceramic paste)
On the polyethylene terephthalate (PET) film subjected to the release treatment, the obtained ceramic paste was applied and dried so that the film thickness after drying was 20 μm, and a sheet made of ceramic paste (ceramic paste sheet) was produced. .

(Surface roughness measurement)
About the obtained ceramic paste sheet, surface roughness Ra was measured based on JIS B 0601 (1994), and the surface roughness of the ceramic paste sheet was evaluated. In general, the higher the dispersibility of the ceramic paste, the smaller the surface roughness of the ceramic paste sheet.

(Criteria)
◎ Less than 0.04 μm ○ 0.04 μm or more, less than 0.06 μm Δ 0.06 μm or more, less than 0.08 μm × 0.08 μm or more

(3) Tensile elastic modulus Based on JIS K 7113, tensile modulus (MPa) was measured using TENSILON (manufactured by Shimadzu Corporation, AUTOGRAPH AGS-J) under a tensile speed of 20 mm / min.

(Criteria)
◎ 1200 MPa or more ○ 1000 MPa or more, less than 1200 MPa Δ 800 MPa or more, less than 1000 MPa × less than 800 MPa

(4) Adhesiveness (production of ceramic green sheets)
100 parts by weight of barium titanate powder (manufactured by Sakai Chemical Co., Ltd., BT01) is added to a mixed solvent of 1 part by weight of “ED216” manufactured by Tsujimoto Kasei Co., Ltd., 20 parts by weight of ethanol and 20 parts by weight of toluene, and a bead mill (manufactured by Imex Corporation). A ceramic dispersion was prepared by stirring for 180 minutes using a ready mill).
Next, 8 parts by weight of the polyvinyl acetal resin (B3), 50 parts by weight of ethanol and 50 parts by weight of toluene were stirred and dissolved, and the resulting resin solution was added to the ceramic dispersion and stirred for 90 minutes in a bead mill. A slurry composition was obtained.
The obtained slurry composition was coated on a polyethylene terephthalate (PET) film that had been subjected to a mold release treatment so that the film thickness after drying was 20 μm, and dried to produce a ceramic green sheet.

(Adhesive strength measurement)
About the obtained ceramic green sheet and ceramic paste sheet, using an adhesive force measuring instrument at the time of heating (“FCL011” manufactured by Fuji Copian Co., Ltd.), the adhesive strength under thermocompression bonding conditions at a temperature of 80 ° C., a pressure of 0.2 MPa, and 10 seconds is obtained. It was measured.

(Criteria)
◎ 140 g / cm ² or more ○ 100 g / cm ² or more, less than 140 g / cm ² Δ 60 g / cm ² or more, less than 100 g / cm ² × less than 60 g / cm ²

ADVANTAGE OF THE INVENTION According to this invention, the dispersibility of ceramic powder can be improved significantly, and the ceramic paste which has high intensity | strength and the outstanding adhesiveness can be provided.

Claims (5)

A ceramic paste comprising a ceramic powder, a resin component, an ester compound having a structure represented by the following formula (1) and having one or more hydroxyl groups in a molecule, and a solvent.

R ¹ and R ² represent a structural unit having C, H or O. The ceramic paste according to claim 1, wherein R ¹ or R ² is a structural unit having 8 or more carbon atoms. The ceramic paste according to claim 1 or 2, which contains 0.01 to 20 parts by weight of an ester compound with respect to 100 parts by weight of the ceramic powder. The resin component contains a polyvinyl acetal resin A having a polymerization degree of 20 to 400 and a hydroxyl group amount of 20 to 30 mol%, and a polyvinyl acetal resin B having a polymerization degree of 450 to 4000 and a hydroxyl group amount of 20 to 30 mol%. The ceramic paste according to claim 1, 2 or 3. 5. The ceramic paste according to claim 4, wherein the addition amount of the polyvinyl acetal resin A is 0.01 to 10 parts by weight with respect to 100 parts by weight of the ceramic powder.