JP2007022828A - Ceramic paint and method for manufacturing multilayered electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic paint which contains a reaction-curable resin, prevents the gelation in the state of a paint, is suitable for obtaining a green sheet having high sheet strength and moderate flexibility, and can effectively prevent the occurrence of a so-called sheet attack phenomenon, and a multilayered electronic component which is manufactured by using the paint and has a reduced shortcircuit defect rate. <P>SOLUTION: The ceramic paint for forming a green sheet contains a ceramic material, a setting acrylic resin with an acid value of 2-10 mg×KOH/g, and a solvent, and the multilayered electronic component is manufactured by using the ceramic paint. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a green sheet for manufacturing a multilayer electronic component such as a multilayer ceramic capacitor that does not generate a so-called sheet attack phenomenon and has a low short-circuit defect rate when an electrode pattern layer is formed on the surface of the green sheet. And a method of manufacturing a multilayer electronic component such as a multilayer ceramic capacitor using the paint.

  As a method for manufacturing a multilayer electronic component such as a capacitor, a piezoelectric element, a PTC thermistor, an NTC thermistor, or a varistor, for example, the following method is known. First, a ceramic coating containing a ceramic raw material powder, an organic binder, a plasticizer, a solvent and the like is formed into a sheet shape on a flexible support (for example, a PET film) by a doctor blade method or the like to obtain a green sheet. On the green sheet, an electrode layer paste containing an electrode material such as palladium, silver, or nickel is printed in a predetermined pattern to form an electrode pattern layer.

  When obtaining a laminated structure, the obtained green sheets are laminated so as to have a desired laminated structure, and a ceramic green chip is obtained through a press cutting process. The binder in the ceramic green chip thus obtained is burned out and fired at 1000 ° C. to 1400 ° C., and terminal electrodes such as silver, silver-palladium, nickel, or copper are applied to the obtained sintered body. Form a multilayer electronic component.

  In the above-described manufacturing method, for example, when manufacturing a multilayer ceramic capacitor, it is conceivable to reduce the thickness of the dielectric layers per layer and increase the number of stacks as a technique for reducing the size and increasing the capacity.

  However, in the conventional method in which the step of printing the electrode pattern on the dried green sheet is a wet-on-dry method, the green sheet is eroded by the solvent during electrode printing (sheet attack by the solvent), There is a problem that the thickness of the green sheet on the lower surface of the electrode printing portion is reduced, and short circuit defects are likely to occur.

  Therefore, the present inventors have previously proposed to use a reactive curable resin as an organic binder contained in a ceramic paint for forming a green sheet (Japanese Patent Application No. 2004-287847, for example, as a reactive curable resin). , Thermosetting or ultraviolet curable acrylic resin, etc. are used). According to this technology, after forming the ceramic paint into a sheet and forming a green sheet, before printing the electrode layer paste, by reacting and curing the reactive curable resin contained in the green sheet, The reaction curable resin that was soluble in the solvent before the reaction is changed into a resin that is insoluble in any solvent by three-dimensional crosslinking after the reaction. For this reason, even if the electrode layer paste containing the solvent is printed on the green sheet after the reaction and curing, it is hardly affected by the sheet attack caused by the solvent, and is effective in preventing short circuit defects.

  However, in the above technique, if the molecular weight of the reaction curable resin before the reaction (unreacted state) is increased in order to improve the sheet strength, there is a problem that the ceramic paint gels and cannot be formed into a sheet. . Therefore, in the above technique, there is still room for improvement regarding the sheet strength.

  An object of the present invention is to obtain a green sheet having a high sheet strength and appropriate flexibility while preventing gelation in the state of a paint in a ceramic paint containing a reactive curable resin as a binder. And a method for producing a multilayer electronic component that does not cause a so-called sheet attack phenomenon when the electrode pattern layer is formed on the surface of the green sheet and results in a low short-circuit defect rate of the electronic component obtained as a result. Is to provide.

  In order to achieve the above object, according to the present invention, a ceramic paint for forming a green sheet comprising a ceramic raw material, a curable acrylic resin having an acid value in the range of 2 to 10 mg · KOH / g, and a solvent. Is provided.

Alternatively, according to the present invention, the ceramic raw material, a curable acrylic resin, and a solvent are contained,
The curable acrylic resin has a weight ratio of a component constituting an acid value and a component that does not substantially constitute an acid value (component constituting an acid value: component not substantially constituting an acid value) = A ceramic paint for forming a green sheet is provided in the range of 1:99 to 5:95.

Preferably, containing a ceramic raw material, a curable acrylic resin, and a solvent,
The acid value of the curable acrylic resin is in the range of 2 to 10 mg · KOH / g,
The curable acrylic resin has a weight ratio of a component constituting an acid value and a component that does not substantially constitute an acid value (component constituting an acid value: component not substantially constituting an acid value) = It is contained in the range of 1:99 to 5:95.

  Preferably, the component constituting the acid value is a (meth) acrylic acid monomer unit, and the component not substantially constituting the acid value is a (meth) acrylic acid ester monomer unit. The component constituting the acid value may not be copolymerized in the acrylic resin, may be contained in a so-called free acid state, or may be contained in a state copolymerized in the acrylic resin. Also good.

  Preferably, the curable acrylic resin has a weight average molecular weight (Mw) of 50,000 to 500,000.

  Preferably, the curable acrylic resin has a glass transition temperature (Tg) of 0 to 50 ° C.

  Preferably, the curable acrylic resin is contained in an amount of 6 to 12 parts by weight (excluding 12 parts by weight) with respect to 100 parts by weight of the ceramic raw material.

  Preferably, the solvent is contained in an amount of 200 to 300 parts by weight with respect to 100 parts by weight of the ceramic raw material.

Preferably, the curable acrylic resin is a thermosetting acrylic resin, and
The ceramic paint further includes a thermal polymerization initiator for curing the thermosetting acrylic resin.

Preferably, the curable acrylic resin is an ultraviolet curable acrylic resin, and
The ceramic paint further includes an ultraviolet polymerization initiator for curing the ultraviolet curable acrylic resin.

A method for manufacturing a multilayer electronic component according to the present invention includes:
Forming a green sheet using any one of the above ceramic paints;
Drying the green sheet;
Reacting the curable acrylic resin contained in the green sheet after drying to cure the green sheet;
Applying an internal electrode layer paste on the surface of the cured green sheet to form an internal electrode pattern;
Laminating the green sheet on which the internal electrode pattern is formed to obtain a green chip;
Firing the green chip.

In the production method of the present invention, when a thermosetting acrylic resin is used as the curable acrylic resin in the paint, and a thermal polymerization initiator is further contained,
It is preferable to react the curable acrylic resin by heating the green sheet after drying at a temperature of 80 to 100 ° C. (excluding 100 ° C.).

Alternatively, in the production method of the present invention, when a UV curable acrylic resin is used as the curable acrylic resin in the paint and an ultraviolet polymerization initiator is further contained, the green sheet after drying is used. Te, 50 to 500 mJ / cm ² (however, excluding 500 mJ / cm ²⁾ by irradiation of ultraviolet light of, it is preferable to react the curable acrylic resin.

  In the manufacturing method of this invention, Preferably, the drying temperature at the time of green sheet formation is 50-100 degreeC (however, except 100 degreeC).

In the manufacturing method of this invention, Preferably, the thickness of the said green sheet after drying is 3 micrometers or less, More preferably, it is 0.5-1 micrometer.
The ceramic raw material is preferably a basic raw material containing Ba ²⁺ , Sr ²⁺ and Ca ²⁺ , and particularly preferably has an isoelectric point in the range of 9-12.
Preferably, the ceramic raw material has an average particle size of 0.1 to 0.25 μm.

  Examples of the multilayer electronic component include, but are not limited to, surface mount (SMD) chip electronic components such as multilayer ceramic capacitors, piezoelectric multilayer components, chip varistors, and chip thermistors.

  The ceramic paint for forming a green sheet according to the present invention comprises a curable acrylic resin whose acid value is controlled in a specific range, or a curable acrylic resin whose content of the component constituting the acid value is in a specific range. use. Therefore, it is possible to obtain a green sheet having high sheet strength and appropriate flexibility while preventing gelation in the paint state.

  In the method for producing a multilayer electronic component using the ceramic paint of the present invention, after forming a green sheet using the ceramic paint of the present invention, the curable acrylic resin contained in the green sheet is reacted and cured. The cured acrylic resin changes into a resin that is insoluble in any solvent, so even if an electrode pattern is subsequently formed on the surface of the green sheet by a printing method, the solvent contained in the electrode pattern erodes the green sheet. There is nothing to do (sheet attack with solvent). Therefore, short circuit defects of the electronic component obtained as a result can be reduced.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

  As shown in FIG. 1, a multilayer ceramic capacitor 1 according to this embodiment as an example of a multilayer electronic component includes a capacitor element body 10 having a configuration in which interlayer dielectric layers 2 and internal electrode layers 3 are alternately stacked. Have. At both ends of the capacitor element body 10, a pair of external electrodes 4 are formed which are electrically connected to the internal electrode layers 3 arranged alternately in the element body 10. The shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped shape. Also, there is no particular limitation on the dimensions, and it may be an appropriate dimension according to the application. Usually, (0.6 to 5.6 mm) × (0.3 to 5.0 mm) × (0.3 ˜1.9 mm).

  The internal electrode layers 3 are laminated so that the end faces are alternately exposed on the surfaces of the two opposite ends of the capacitor element body 10. The pair of external electrodes 4 are formed at both ends of the capacitor element body 10 and are connected to the exposed end surfaces of the alternately arranged internal electrode layers 3 to constitute a capacitor circuit.

  In the capacitor element body 10, outer dielectric layers 2 a are disposed at both outer ends in the stacking direction of the internal electrode layer 3 and the interlayer dielectric layer 2 to protect the inside of the element body 10.

The composition of the interlayer dielectric layers 2 and outside dielectric layers 2a are not particularly limited in the present invention, for _{example, {(Ba (1-x} -y) Ca x Sr y) O} A (Ti (1-z) composed of a dielectric ceramic composition having a main component represented by Zr _{z) B} O _2. A, B, x, y, and z are all in an arbitrary range, but preferably 0.990 ≦ A / B ≦ 1.010, 0 ≦ x ≦ 0.80, and 0 ≦ y ≦ 0. .5, 0.01 ≦ z ≦ 0.98. As subcomponents included in the dielectric ceramic composition together with the main component, Sr, Y, Gd, Tb, Dy, V, Mo, Zn, Cd, Ti, Sn, W, Ba, Ca, Mn, Mg, Cr Subcomponents including one or more selected from oxides of Si, Si, and P are exemplified.

  By adding subcomponents, low-temperature firing is possible without deteriorating the dielectric properties of the main component, reducing the reliability failure when the interlayer dielectric layer is thinned, and extending the life. be able to. However, in the present invention, the composition of the interlayer dielectric layer is not limited to the above.

  The conditions such as the number and thickness of the interlayer dielectric layers 2 shown in FIG. 1 may be appropriately determined according to the purpose and application. In this embodiment, the thickness of the interlayer dielectric layer 2 is 2 μm to It is about 50 μm. The thickness of the outer dielectric layer 2a is, for example, about 100 μm to several hundred μm.

  The conductive material contained in the internal electrode layer 3 is not particularly limited, but a base metal can be used because the constituent material of the interlayer dielectric layer 2 has reduction resistance. As the base metal used as the conductive material, Ni, Cu, Ni alloy or Cu alloy is preferable. When the main component of the internal electrode layer 3 is Ni, a method of firing at a low oxygen partial pressure (reducing atmosphere) is employed so that the dielectric is not reduced. On the other hand, a method of shifting the composition ratio from the stoichiometric composition so that the dielectric is not reduced is employed.

  The thickness of the internal electrode layer 3 may be appropriately determined according to the application and the like, but it is usually preferably about 0.5 to 5 μm, particularly about 1 to 2.5 μm.

The conductive material contained in the external electrode 4 is not particularly limited, but usually Cu, Cu alloy, Ni, Ni alloy, or the like is used. Of course, Ag, an Ag—Pd alloy, or the like can also be used. In the present embodiment, inexpensive Ni, Cu, and alloys thereof can be used.
The thickness of the external electrode may be appropriately determined according to the use, etc., but is usually preferably about 10 to 50 μm.

  Next, a method for manufacturing the multilayer ceramic capacitor 1 will be described. In this embodiment, the green chip is manufactured by a normal printing method or a sheet method using a paste, fired, and then printed or transferred and fired by external electrodes. Hereinafter, the manufacturing method will be specifically described.

  (1) First, a dielectric layer paste is prepared.

  In the present embodiment, the dielectric layer paste is composed of the ceramic paint of the present invention.

Ceramic paint The ceramic paint of the present invention is a reaction-curing paint containing a ceramic raw material, a curable acrylic resin, and a solvent.

The ceramic raw material (dielectric raw material) is composed of the raw material constituting the main component, the raw material constituting the subcomponent, and, if necessary, the sintering aid according to the composition of the dielectric ceramic composition described above. Raw material to be used.

In the present embodiment, it is preferable to use a material containing Ba ²⁺ , Sr ²⁺ , and Ca ^{2+ and} having an isoelectric point of 9 to 12 as a material constituting the main component. By setting the isoelectric point within a predetermined range, aggregation of each raw material component at the time of coating can be prevented. When the isoelectric point is out of the above range, the elution of Ba ions becomes large, and the ceramic paint is easily gelled.

  As the raw material constituting the main component, a composite oxide containing Ti, Ba, Sr, Ca, Zr and / or a compound that becomes a composite oxide by firing is used. The raw materials constituting the subcomponents include oxides of Sr, Y, Gd, Tb, Dy, V, Mo, Zn, Cd, Ti, Sn, W, Ba, Ca, Mn, Mg, Cr, Si, and P One or more, preferably three or more single oxides or composite oxides selected from compounds that become oxides upon firing are used.

The dielectric material does not necessarily include a sintering aid, but when a sintering aid is included, for example, an oxide of Si or Li and / or a compound that becomes an oxide by firing is used. . Examples of the compound that becomes an oxide upon firing include carbonates, nitrates, oxalates, and organometallic compounds. Of course, you may use together an oxide and the compound which becomes an oxide by baking.
These raw material powders usually have an average particle size of about 0.005 to 5 μm, preferably about 0.1 to 0.25 μm.

In order to obtain a dielectric material from such a raw material powder, for example, the following may be performed. First, the starting materials are blended in a predetermined quantitative ratio, and are wet mixed by, for example, a ball mill or the like. Next, it is dried by a spray dryer or the like, and then calcined to obtain a dielectric oxide of the above formula constituting the main component. In addition, calcination is normally performed at 500-1300 degreeC, Preferably it is 500-1000 degreeC, More preferably, it is 800-1000 degreeC in the air for about 2 to 10 hours. Next, it is pulverized to a predetermined particle size by a jet mill or a ball mill to obtain a dielectric material. The particle size of the obtained dielectric material is preferably about 0.1 to 0.25 μm. The subcomponent and the sintering aid (such as SiO ₂ or Li ₂ O) are calcined separately from the main component and mixed with the obtained dielectric material.

Curable acrylic resin The curable acrylic resin used in the present invention is a resin composed of a reactive curable acrylic polymer or copolymer. The curable acrylic resin used in the present invention is characterized in that the acid value is controlled within a specific range. This point will be described later.

  In the following description, the acrylic polymer or copolymer described above is “(meth) acrylic acid ester, (meth) acrylic acid, a functional monomer added as necessary, The case of “copolymerizing the body” will be exemplified and described as an embodiment.

The (meth) acrylic acid ester (meth) acrylic acid ester usually means an ester such as acrylic acid or methacrylic acid having an alkyl group having 30 or less carbon atoms. In the curable acrylic resin used in the present invention, the (meth) acrylic acid ester is a component that does not substantially constitute an acid value. Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t- Butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, i-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, i-nonyl (meth) acrylate, stearyl (meth) Examples include acrylate. In particular, methyl methacrylate (MMA) as an example of an alkyl methacrylate is preferable.

  The amount of (meth) acrylic acid ester used is, for example, 50% by weight or more, preferably 60 to 100% by weight, particularly preferably, in a total of 100% by weight of all monomers constituting the acrylic polymer or copolymer. An amount of about 70 to 99% by weight is preferred.

(Meth) acrylic acid (meth) acrylic acid usually means acrylic acid or methacrylic acid having an alkyl group with 30 or less carbon atoms. Specific examples of (meth) acrylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and citraconic acid. (Meth) acrylic acid is a component constituting an acid value, and is often contained as a free fatty acid in the (meth) acrylic acid ester.

  In the present embodiment, in the curable acrylic resin, the component constituting the acid value and the component not substantially constituting the acid value are expressed by weight ratio (component constituting the acid value: substantially the acid value). Components not constituting) = 1: 99 to 5:95. That is, a (meth) acrylic acid monomer unit that is a component that constitutes an acid value and a (meth) acrylic acid ester monomer unit that is a component that does not substantially constitute an acid value, in a weight ratio of 1 : It is preferable to set it as the range of 99-5: 95.

  By controlling the acid value of the curable acrylic resin in the range of 2 to 10 mg · KOH / g by setting the ratio of the component constituting the acid value and the component not substantially constituting the acid value to such a ratio. Can do. In this embodiment, the acid value (unit: mg · KOH / g) represents the weight (unit, mg) of KOH necessary for neutralizing the acid contained in 1 g of the curable acrylic resin. It is a thing. A low acid value means that the acid amount in the curable acrylic resin is small, whereas a high acid value means that the acid amount is large. If the acid value is too low, the strength of the resulting green sheet will be insufficient, resulting in poor retention, and as a result, a good laminate cannot be obtained. On the other hand, if the acid value is too high, the ceramic paint will be gelled and cannot be applied. The component constituting the acid value ((meth) acrylic acid in this embodiment) may be contained in a state of being copolymerized in the curable acrylic resin, or may be copolymerized in the curable acrylic resin. Instead, it may be in a free state.

Functional monomer The functional monomer is at least one functional group in addition to the above-mentioned radically polymerizable unsaturated group for copolymerization with (meth) acrylic acid ester or (meth) acrylic acid. Means a monomer having Examples of the functional monomer include a monomer having a functional group such as an amide group or a substituted amide group, an amino group or a substituted amino group, a hydroxyl group, or a mercapto group.

  Specific examples of functional monomers include amide group or substituted amide group-containing monomers (for example, acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylacrylamide (preferably acrylamide, methacrylamide), etc. ); Amino group or substituted amino group-containing monomer (for example, aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylamino) Ethyl methacrylate (preferably N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, etc.); hydroxyl group-containing monomers (for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acetate) Relate, 2-hydroxyethyl methacrylate, allyl alcohol, methallyl alcohol (preferably 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc.); mercapto group-containing single amount Body (for example, vinyl mercaptan, allyl mercaptan, etc.); Among these functional monomers, it is particularly preferable to use at least one monomer selected from an amide group-containing monomer and a substituted amino group-containing monomer. Each of the above-mentioned monomers can be used by appropriately selecting one type or two or more types. The amount of the functional monomer used is, for example, 20% by weight or less, preferably 0 to 15% by weight, particularly preferably 0 in a total of 100% by weight of all monomers constituting the acrylic polymer or copolymer. An amount of about 5 to 10% by weight can be exemplified.

The comonomer comonomer means a monomer copolymerizable with the above-described (meth) acrylic acid ester, (meth) acrylic acid, and a functional monomer. As a comonomer, a saturated fatty acid vinyl ester monomer (for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate); α, β-unsaturated dicarboxylic acid linear chain having 1 to 18 carbon atoms Or branched alkyl esters (eg, dibutyl malate, dibutyl fumarate, dibutyl itaconate, dioctyl malate, dioctyl fumarate, dioctyl itaconate, etc.); aromatic vinyl monomers (eg, styrene, α-methyl styrene, vinyl) Toluene, ethyl vinyl benzene, etc.) Vinyl cyanide monomer (eg, acrylonitrile, methacrylonitrile, etc.); Isocyanates (tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,5-naphthylene diisocyanate Cyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate); and the like.

  The amount of the comonomer used is generally 50% by weight or less, preferably 40% by weight or less, particularly preferably 30% by weight, out of a total of 100% by weight of all monomers constituting the acrylic polymer or copolymer. The following amounts are preferred.

  The method for producing the acrylic polymer or copolymer is not particularly limited, and conventionally known polymerization methods such as solution polymerization and emulsion polymerization that are generally known can be adopted, but the polymerization polymer was obtained by polymerization. In producing the ceramic paint of the present invention from a (co) polymer mixture, it is preferable to employ solution polymerization, which can be performed in a short time with a relatively simple treatment process. In solution polymerization, generally, a predetermined organic solvent, a monomer mixture, a polymerization initiator, and a chain transfer agent to be used as necessary are charged in a polymerization tank and stirred in a nitrogen stream or at the reflux temperature of the organic solvent. The reaction is performed by heating for several hours.

  In addition, in the curable acrylic resin according to an embodiment, (meth) acrylic acid ester, (meth) acrylic acid, functional monomer added as necessary, comonomer type and addition ratio By appropriate selection, a thermosetting curable acrylic resin suitable for thermosetting or an ultraviolet curable curable acrylic resin suitable for ultraviolet curing can be obtained. When the curable acrylic resin is a thermosetting curable acrylic resin, it is preferable to add a thermal polymerization initiator to the ceramic paint. Similarly, when an ultraviolet curable curable acrylic resin is used, an ultraviolet polymerization initiator is preferably added to the ceramic paint.

Glass transition temperature The acrylic polymer or copolymer used in the present invention has a glass transition temperature (Tg) of 0 to 50 ° C, preferably 0 to 30 ° C, more preferably 0 to 20 ° C, particularly preferably. 0-10 ° C. When Tg is too high, the strength of the green sheet when formed into a sheet becomes too high, the flexibility tends to decrease, and it tends to break easily. When Tg is too low, the sheet strength becomes too low to satisfy the shape retention.

  The Tg of the acrylic polymer or copolymer can be changed by selecting the type of functional group to be copolymerized with the main component (meth) acrylate.

Molecular Weight The acrylic polymer or copolymer that can be used in the present invention has a weight average molecular weight (Mw) of preferably 50,000 to 500,000, more preferably 100,000 to 500,000. If Mw is too high, it becomes difficult not only to produce such an acrylic polymer or copolymer, but also tends to cause a disadvantage that the viscosity of the final ceramic paint becomes too high. If Mw is too low, the sheet strength of the green sheet tends to decrease. In particular, since the acid value of the curable acrylic resin according to this embodiment is controlled within the above range, the gelation of the paint when the Mw, which has been a problem in the past, is relatively large is effectively prevented. can do.

  In the present invention, as the above-mentioned acrylic polymer or copolymer, for example, polyester acrylate bifunctional copolymer, urethane acrylate bifunctional copolymer, (methyl methacrylate bifunctional copolymer (above, Nippon Carbide Industries, Ltd.) Manufactured), ethyl methacrylate bifunctional copolymer, n-butyl methacrylate bifunctional copolymer (above, manufactured by Toagosei Co., Ltd.), and the like.

  The content of the acrylic polymer or copolymer is preferably 6 to 12 parts by weight (excluding 12 parts by weight), more preferably 8 to 12 parts by weight (however, with respect to 100 parts by weight of the ceramic raw material. 12 parts by weight is excluded), more preferably 10 to 12 parts by weight (however, 12 parts by weight is excluded). If the content of the acrylic polymer or copolymer is too small, the sheet has no shape retention and tends to be difficult to form into a sheet. The sheet strength is improved with an increase in the content of the acrylic polymer or copolymer. However, if the content is too large, there is a disadvantage that cracks occur when the sheet is formed.

As the polymerization initiator , when a thermosetting curable acrylic resin is used as the curable acrylic resin, it is preferable to use a thermal polymerization initiator. The thermal polymerization initiator is a compound capable of generating radicals (active species) by heating and reacting with the reactive group of the above acrylic polymer or copolymer to start radical polymerization. If there is no particular limitation. In this embodiment, it is preferable to use an amine as the polymerization initiator.

  Examples of such amines include those having a structure in which a methyl group, an ethyl group, a butyl group, a cyclohexyl group, a benzyl group, or the like is bonded to a nitrogen element. Specifically, aliphatic primary amines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, and cyclohexylamine; aliphatic secondary amines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, and dibutylamine Amine; Aliphatic tertiary amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine; Aromatic primary amines such as aniline and toluidine; Aromatic secondary amines such as diphenylamine; Triphenylamine And aromatic tertiary amines. Among these, aliphatic primary amines, aliphatic secondary amines, aromatic primary amines, and aromatic primary amines are preferable.

  The content (blending amount) of the thermal polymerization initiator is preferably 1 to 6 parts by weight (excluding 6 parts by weight), more preferably 3 to 100 parts by weight of the acrylic polymer or copolymer. 6 parts by weight (excluding 6 parts by weight). If the content of the polymerization initiator is too small, poor curing may occur. Conversely, if the content is too large, the flexibility of the resulting green sheet may deteriorate.

  Alternatively, when an ultraviolet curable curable acrylic resin is used as the curable acrylic resin, it is preferable to use an ultraviolet polymerization initiator. As an ultraviolet polymerization initiator, a compound capable of generating radicals (active species) upon irradiation with ultraviolet rays and reacting with the reactive group of the above-mentioned acrylic polymer or copolymer to initiate radical polymerization If it is, it will not specifically limit. In the present invention, one or more compounds selected from benzophenone compounds, acetophenone compounds, benzylacetophenone compounds, and benzylphenone compounds are preferably used as the ultraviolet polymerization initiator. By using one or more compounds of these groups, excessive curing can be prevented when the resin is cured, and as a result, flexibility to the green sheet can be imparted.

  Examples of the acetophenone compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methylpropiophenone, and 2-hydroxymethyl-2. -Methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, p-dimethylaminoacetophenone, p-tertiarybutyldichloroacetophenone, p-tertiarybutyltrichloroacetophenone, p-azidobenzal Acetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -Butanone-1, benzoy , Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin -n- butyl ether, and benzoin isobutyl ether. These can be used alone or in combination of two or more.

  Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, Michler ketone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide. These can be used alone or in combination of two or more.

  Examples of the benzylacetophenone compound include dibenzylacetophenone. These can be used alone or in combination of two or more.

  Examples of the benzylphenone compound include dibenzylphenone. These can be used alone or in combination of two or more.

  The content (blending amount) of the ultraviolet polymerization initiator is preferably 0.5 to 3.0 parts by weight, more preferably 1.0 to 2.0 parts per 100 parts by weight of the acrylic polymer or copolymer. Parts by weight. If the content of the polymerization initiator is too small, curing failure may occur. On the other hand, if the content is too large, there is an inconvenience that brittleness in terms of sheet strength and elongation properties occurs due to excessive curing reaction.

Solvent In addition to the ceramic raw material and the curable acrylic resin described above, the ceramic coating of the present invention usually further contains a solvent.

  As the solvent, aromatic hydrocarbons, aliphatic or aliphatic hydrocarbons, esters, ketones, alcohols and the like used in the production of acrylic polymers or copolymers are used. These solvents can be used alone or in admixture of two or more.

  The content of the solvent is preferably 200 to 300 parts by weight, more preferably 240 to 270 parts by weight with respect to 100 parts by weight of the ceramic raw material. If the amount of the solvent is too small, the resin cannot be completely dissolved and a ceramic paint cannot be obtained. On the other hand, if the amount is too large, it is difficult for the solvent to fly in the drying step, the residual solvent increases, and a high-strength green sheet tends not to be obtained.

  In the ceramic paint of the present invention, the ceramic raw material, the acrylic polymer or copolymer, and the polymerization initiator in total are preferably 25 to 35% by weight, more preferably 28%, based on 100% by weight of the entire ceramic paint. The viscosity is preferably about 20 to 80 cps, more preferably about 40 to 60 cps (rotary viscometer; 25 ° C .; 10 rpm).

Other Components The ceramic paint of the present invention may contain an additive selected from a dispersant, a plasticizer, a dielectric, a glass frit, an insulator, a charging aid and the like, if necessary. However, the total content of these is preferably 10% by weight or less.

  Examples of the plasticizer include phthalate esters such as dioctyl phthalate and benzylbutyl phthalate, adipic acid, phosphate esters, glycols, and the like. The weight ratio of the plasticizer in the coating material when blending the plasticizer is not particularly limited, and is preferably 40 to 70 parts by weight with respect to 100 parts by weight of the acrylic polymer or copolymer. If the amount of the plasticizer is too small, the green sheet tends to be brittle. If the amount is too large, the plasticizer oozes out and is difficult to handle.

  In the present embodiment, the ceramic raw material, the acrylic polymer or copolymer, the polymerization initiator, and the solvent described above are mixed with, for example, a ball mill or the like for the dielectric layer made of the ceramic paint of the present invention. A paste (slurry) can be obtained. In mixing, after first mixing the ceramic raw material with a solvent to obtain a primary dispersion, the acrylic polymer or copolymer and the polymerization initiator are added to the primary dispersion and the content described above. You may add and disperse | distribute so that it may become. When other components such as a plasticizer are added, they may be added and mixed during the secondary mixing.

  (2) Next, the dielectric layer paste is formed into a sheet.

  In this embodiment, it is possible to form the interlayer dielectric layer 2 and the outer dielectric layer 2a shown in FIG. 1 using the dielectric layer paste. The case where the dielectric layer 2 is formed will be mainly described.

  In the present embodiment, a nozzle coating method, a doctor blade method, or the like is used as a means for forming the dielectric layer paste into a sheet. Specifically, the dielectric layer paste is applied on the carrier sheet with a predetermined thickness by a nozzle coating method, a doctor blade method, or the like to form a green sheet.

  The green sheet is dried after being formed on the carrier sheet. The drying temperature of the green sheet is preferably 50 to 100 ° C. (excluding 100 ° C.), and the drying time is preferably 1 to 20 minutes. If the drying temperature is too low, residual solvent remains, the shape retention cannot be maintained, and the strength of the green sheet decreases. On the other hand, if it is too high, the solvent rapidly evaporates and the sheet surface becomes rough.

  The thickness of the green sheet after drying shrinks to a thickness of 5 to 25% as compared to before drying. The thickness of the green sheet after drying is preferably 3 μm or less, more preferably 0.5 to 1 μm.

  As the carrier sheet, for example, a PET film or the like is used, and a film coated with silicon or the like is preferable in order to improve peelability. The thickness of these carrier sheets is not particularly limited, but is preferably 5 to 100 μm.

  (3) After forming a green sheet on the carrier sheet and drying, the curable acrylic resin is reacted and cured. Specifically, when a thermosetting curable acrylic resin is used as the curable acrylic resin, the curable acrylic resin contained in the green sheet is cured by heating the green sheet. Alternatively, when an ultraviolet curable curable acrylic resin is used as the curable acrylic resin, the curable acrylic resin contained in the green sheet is cured by irradiation with ultraviolet rays. By doing so, the green sheet is not attacked when the internal electrode pattern described later is formed.

  When using a thermosetting curable acrylic resin, the heating temperature for curing the ceramic paint is preferably 80 to 100 ° C. (except 100 ° C.). If the heating temperature is too low, the curing time becomes long or the curing becomes insufficient. Conversely, if the heating temperature is too high, the curing of the resin is promoted but tends to be brittle.

Alternatively, when an ultraviolet curable curable acrylic resin is used, the amount of UV irradiation used to cure the ceramic paint is adjusted by adjusting the lamp intensity, the distance to the irradiated surface, and the irradiation time. dose can be adjusted to,該照ray amount is measured using an integrating actinometer the irradiated surface, preferably 50 to 500 mJ / cm ² (however, excluding 500 mJ / cm ^2), more preferably 100 to 500 mJ / cm ² (However, 500 mJ / cm ² is excluded). If the irradiation dose is too small, the curing time becomes long. Conversely, if the irradiation dose is too large, curing of the resin is promoted but tends to be brittle.

  The green sheet formed as described above is a portion constituting the interlayer dielectric layer 2 shown in FIG. 1, and preferably has a thickness of about 0.5 to 3 μm. Apart from this interlayer dielectric layer green sheet, an outer dielectric layer green sheet having a thickness of preferably 100 μm or more, more preferably 140 μm or more, and particularly preferably 250 μm or more is formed.

  (4) Next, the internal electrode layer paste to be the internal electrode layer 3 shown in FIG. 1 is applied and dried in a predetermined pattern on the surface of the interlayer dielectric layer green sheet to form an internal electrode pattern.

  The internal electrode layer paste is prepared by kneading a conductive material made of various conductive metals and alloys, or various oxides, organometallic compounds, resinates, and the like, which become the conductive material described above after firing, and an organic vehicle. .

  As a conductor material used when manufacturing the internal electrode layer paste, Ni, Ni alloy, or a mixture thereof is used. There are no particular restrictions on the shape of such a conductive material, such as a spherical shape or a flake shape, or a mixture of these shapes may be used. Moreover, what is necessary is just to use what the average particle diameter of a conductor material is about 0.1-10 micrometers normally, Preferably it is about 0.2-1 micrometer.

  (5) Next, the interlayer dielectric layer green sheets coated with the internal electrode layer paste are alternately stacked, and the outer dielectric layer green sheets are formed in a single layer or a plurality of layers at both ends in the stacking direction. Laminate in layers.

(6) Next, the obtained laminate is cut into a predetermined laminate size to form a green chip, and then subjected to a binder removal process, a firing process, and an annealing process performed as necessary. An external electrode paste is printed or transferred to a capacitor element body 10 composed of a bonded body and fired to form external electrodes 4 and 4, whereby the multilayer ceramic capacitor 1 is manufactured. The external electrode paste may be prepared in the same manner as the internal electrode layer paste described above.
The multilayer ceramic capacitor 1 manufactured in this way is mounted on a printed circuit board by soldering or the like and used for various electronic devices.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
In the embodiment described above, a multilayer ceramic capacitor is manufactured using the coating composition according to the present invention. As an electronic component manufactured using the coating composition according to the present invention, as shown in FIG. Furthermore, the present invention is not limited to a multilayer ceramic capacitor in which a large number of internal electrode layers 3 are stacked. For example, in FIG. 1, a large number of internal electrode layers 3 are stacked, but there are capacitors and other electronic components in which only one pair or only a plurality of pairs of internal electrodes are stacked.

  Further, in the above-described embodiment, after or before the internal electrode pattern is formed on the surface of the interlayer dielectric layer green sheet by the printing method, the surface gap (in which the internal electrode pattern on the green sheet is not formed) A blank pattern layer having substantially the same thickness as the internal electrode pattern may be formed in the blank pattern portion. Thereby, generation | occurrence | production of a level | step difference can be prevented. The paste for forming the blank pattern layer contains a ceramic raw material having the same composition and the same average particle size as the ceramic raw material contained in the interlayer dielectric layer green sheet, and an organic vehicle.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1 (Sample No. 2)
First, the following pastes were prepared.
Dielectric layer paste A
As starting materials, main component materials: BaTiO ₃ (average particle size 0.2 μm / BT02 powder manufactured by Sakai Chemical Industry Co., Ltd.) and subcomponent materials were prepared. As an auxiliary component raw material, 2 mol of Y ₂ O ₃ , 2 mol of MgO, 0.4 mol of MnO, 0.1 mol of V ₂ O ₅ , 3 mol with respect to 100 mol of the main component raw material (Ba _0.6 Ca _0.4 ) SiO ₃ was used. 100 parts by weight of these starting materials, 1 part by weight of a dispersant (polymeric dispersant / San Nopco, SN5468), and 100 parts by weight of ethanol are charged into a polyethylene container together with zirconia balls (2 mmφ) for 16 hours. A dielectric mixed solution was obtained by mixing. This dielectric mixed solution was dried at a drying temperature of 120 ° C. for 12 hours to obtain a dielectric material (powder).

  Obtained dielectric material: 100 parts by weight, solvent: 250 parts by weight (MEK: toluene = 71.5: 28.5 (weight ratio)), and 1 part by weight of a block type dispersant (manufactured by Unikema Co., Ltd.) JP4) was mixed with a ball mill for 4 hours for primary dispersion.

  10 parts by weight of a thermosetting curable acrylic resin and 5 parts by weight of an amine compound (trade name SD-326 manufactured by Nippon Carbide) as a thermosetting initiator are added to the dispersion after the primary dispersion. Were mixed for 16 hours in a ball mill and secondarily dispersed to obtain a dielectric layer paste.

  In this example (sample number 2 in Table 1), as the thermosetting curable acrylic resin, a component that uses acrylic acid as a component constituting an acid value and does not substantially constitute an acid value. The curable acrylic resin produced by using methyl methacrylate was used. In this example, as the curable acrylic resin, the content of the monomer unit constituting the acid value and the monomer unit not substantially constituting the acid value is 1:99 by weight ratio. It was.

Measurement of Acid Value The acid value (unit: mg · KOH / g) of the curable acrylic resin was measured by a method based on JIS K 2501. The obtained results are shown in Table 1.

Measurement of Tg The Tg of the curable acrylic resin was measured as follows. First, a resin was made into a lacquer, a resin having a lacquer was formed, and then the solvent was dried to form a film. Using a differential scanning calorimeter (DSC) manufactured by RIGAKU, the curable acrylic resin formed into a film is heated from −150 ° C. to + 150 ° C. at a heating rate of 10 ° C./min, and the differential scanning calorific value is measured. Then, the endothermic curve obtained was differentiated to determine the inflection point, and this inflection point was determined as Tg.

Measurement of Mw Mw of the curable acrylic resin is first measured by gel permeation chromatography (GPC) using tetrahydrofuran as a mobile phase solvent, and the obtained result is calculated as a standard polystyrene equivalent value. Asked.

Measurement of viscosity of ceramic paint Viscosity of ceramic paint (unit: cps) is measured using a B-type viscometer by measuring the viscosity at a shear rate of 10 rpm and a measurement temperature of 25 ° C. went.

The presence or absence of gelation of the ceramic paint The presence or absence of gelation of the ceramic paint is evaluated by allowing the obtained paint to stand for 20 minutes, pouring the paint after standing into a predetermined container, and checking for fluidity. did. When the paint remains in a liquid state and has fluidity, it is determined that the gelation is “none”. When the paint is solidified and loses fluidity, the gelation is “ It was judged as “Yes”.

Dielectric layer paste B
A dispersion same as the dispersion after the primary dispersion of the dielectric layer paste A is prepared, and a thermoplastic acrylic resin (MM747 resin manufactured by Fujikura Kasei Co., Ltd.) 10 is added to the dispersion without adding a curable acrylic resin. A dielectric layer paste B was obtained in the same manner as the dielectric layer paste A except that parts by weight were added.

BaTiO ₃ powder (average particle size 0.2 μm / BT02 powder manufactured by Sakai Chemical Industry Co., Ltd.): 20 parts by weight, organic vehicle: 58 with respect to 100 parts by weight of Ni particles having an internal electrode layer paste average particle size of 0.2 μm Parts by weight (8 parts by weight of polyvinyl butyral resin dissolved in 92 parts by weight of terpineol), bis (2-ethylhexyl) phthalate DOP as a plasticizer: 50 parts by weight, terpineol: 5 parts by weight, dispersant: 1 part by weight, acetone : 45 parts by weight was added, kneaded with three rolls, and slurried to obtain an internal electrode paste.

Production of Laminate Unit U1 First, the dielectric layer paste A was applied by a nozzle coating method onto a PET film whose surface was peeled off with a silicone resin, and then dried to form a lower green sheet. . The sheet was continuously fed into the drying furnace for drying, the temperature in the drying furnace was 80 ° C., and the drying time was 2 minutes. The lower green sheet was formed so that the film thickness when dried was 0.5 μm.

Next, the obtained lower green sheet is passed through a heat treatment furnace,
Curing temperature: 80 ° C
Curing time: 5 minutes
Under these conditions, a curing treatment by heating was performed.

  The lower green sheet after the curing treatment by heating was evaluated for sheet strength and sheet elongation.

Evaluation of sheet strength Sheet strength was evaluated as follows. Using an Instron tensile tester 5543, the sheet was cut into a dumbbell shape, the sheet was pulled from both ends at a predetermined tensile speed, and the strength at break was defined as the sheet strength. In this example, it was determined that the sheet strength was 6 MPa or more. The results are shown in Table 1.

Evaluation of sheet elongation Sheet elongation was evaluated as follows. Using an Instron tensile tester 5543, the sheet was cut into a dumbbell shape, the sheet was pulled from both ends at a predetermined tensile speed, and the elongation at break was defined as the sheet elongation. In this example, it was determined that the sheet elongation was 10% or more. The results are shown in Table 1.

Next, using the internal electrode paste, printing was performed on the lower green sheet with a screen printer, and then dried under the conditions of 90 ° C. and 10 minutes to form an electrode pattern layer having a predetermined pattern. The internal electrode layer was formed so that the film thickness when dried was 1 μm.
Next, the dielectric layer paste A is applied by a nozzle coating method on the electrode pattern layer of the lower green sheet on which the first electrode pattern layer is formed, and then dried to obtain an intermediate green sheet. Got. The sheet was continuously fed into the drying furnace for drying, the temperature in the drying furnace was set to a predetermined temperature (the same temperature as in the case of the lower green sheet), and the drying time was 2 minutes. The intermediate green sheet was formed so that the film thickness when dried was 1 μm.

  Next, the obtained intermediate green sheet was passed through a heat treatment furnace, and a curing treatment by heating was performed under the same conditions as in the case of the lower green sheet.

  Next, a second electrode pattern layer was formed on the surface of the intermediate green sheet in the same manner as the first electrode pattern layer.

  Next, an upper green sheet was formed on the surface of the second electrode pattern layer after drying by nozzle coating using the dielectric layer paste B. The sheet was continuously fed into a drying furnace at 80 ° C. to dry the solvent. The drying time was 2 minutes. The thickness of the upper green sheet after drying was 0.5 μm.

  In this manner, a laminate unit U1 including the lower green sheet, the first electrode pattern layer, the intermediate green sheet, the second electrode pattern layer, and the upper green sheet was formed on the PET film. .

Preparation of Green Chip A large number of laminate units U1 peeled from the PET film were prepared, and laminated by thermocompression bonding so that the total number of electrode pattern layers was 100. Thus, a laminate was obtained. The conditions at the time of thermocompression bonding were 100 MPa and 70 ° C.

  Next, the obtained laminated body was cut by a dicing machine to obtain a green chip before firing.

  The obtained green chip was observed for the presence or absence of sheet attack.

Measurement of presence or absence of sheet attack The degree of occurrence of sheet attack was measured for the obtained green chip samples. In the measurement, first, 50 green chip samples were embedded in a two-part curable epoxy resin so that the side surfaces of the dielectric layer and the internal electrode layer were exposed, and then the two-part curable epoxy resin was cured. . Next, the green chip sample embedded in the epoxy resin was polished to a depth of 1.6 mm using sandpaper. The sandpaper was polished by using # 400 sandpaper, # 800 sandpaper, # 1000 sandpaper, and # 2000 sandpaper in this order. Next, the sandpaper polished surface was subjected to mirror polishing using diamond paste. Then, using an optical microscope, the polished surface subjected to the mirror polishing treatment was observed at an enlargement magnification of 400 times, and the presence or absence of sheet attack was examined. As a result of observation with an optical microscope, the ratio of the samples in which the sheet attack occurred with respect to all the measurement samples was defined as the sheet attack ratio. The results are shown in Table 1.

  Note that whether or not a sheet attack occurred was determined by whether or not there was a portion in which the thickness of the green sheet was extremely thinner than 50% compared to other portions.

The green chip obtained by firing the green chip was subjected to binder removal processing, firing and annealing (heat treatment) to produce a chip-shaped sintered body. The binder removal was performed at a temperature rising rate: 50 ° C./hour, a holding temperature: 240 ° C., a holding time: 8 hours, and an atmospheric gas: in air. Firing is carried out by heating at a heating rate of 300 ° C./hour, a holding temperature of 1200 ° C., a holding time of 2 hours, a cooling rate of 300 ° C./hour, and an atmosphere gas of N ₂ gas and H ₂ controlled to a dew point of 20 ° C. (5 %) And mixed gas. Annealing (reoxidation) was performed with a holding time: 3 hours, a cooling rate: 300 ° C./hour, and an atmosphere gas: N ₂ gas controlled to a dew point of 20 ° C. The atmosphere gas was humidified using a wetter at a water temperature of 0 to 75 ° C.

  Next, after polishing the end face of the chip-shaped sintered body with sand blasting, an In—Ga alloy paste is applied to the end portion, and then firing is performed to form an external electrode. A sample of a multilayer ceramic capacitor was obtained. The width of the sample after firing was 0.8 mm and the length was 1.6 mm.

Measurement of short circuit defect ratio The short circuit defect ratio was measured by preparing 50 capacitor samples and examining the number of short circuit defects. Specifically, the resistance value was measured using an insulation resistance meter (E2377A multimeter manufactured by HEWLETT PACKARD), and the sample having a resistance value of 100 kΩ or less was defined as a short defect sample. The ratio of samples was defined as the short defect rate. In this example, it was determined that the short defect rate was 0%. The results are shown in Table 1.

Example 2
As the dielectric layer paste A for forming the lower green sheet and the intermediate green sheet, except for changing each condition shown in Table 1, ceramic paint, green Sheets, green chip samples, and capacitor samples were prepared and subjected to similar measurements. The results are shown in Table 1.

That is, in Example 2, as shown in Table 1, samples in which the following conditions were changed were produced.
A curable acrylic resin (sample numbers 1, 3, and 4) in which the ratio of the monomer unit constituting the acid value and the monomer unit not substantially constituting the acid value is changed, and the Mw is changed. The acrylic acrylic resin (Sample Nos. 11 to 13) and the curable acrylic resin (Sample Nos. 21 to 24) with different Tg were respectively changed. Furthermore, when manufacturing a ceramic paint, as conditions other than the kind of curable acrylic resin, the content of the curable acrylic resin (sample numbers 31 to 33), the isoelectric point of BaTiO ₃ (sample numbers 41 and 42), The temperature of the curing treatment (sample numbers 51 to 53), the drying temperature (sample numbers 61 to 63), and the solvent content (sample numbers 71 and 72) were changed.

  The Tg of the curable acrylic resin was changed by changing the functional group. The Mw of the curable acrylic resin was changed by changing the degree of polymerization.

なお、表１中、酸価構成成分の比率は、「酸価を構成する成分の比率／実質的に酸価を構成しない成分」を重量比で表した。

In Table 1, the ratio of the acid value constituents is represented by the weight ratio of “the ratio of the components constituting the acid value / the component not substantially constituting the acid value”.

Evaluation 1
As shown in Table 1, the ratio of the component constituting the acid value of the curable acrylic resin used as the binder of the dielectric layer paste to the component not substantially constituting the acid value was set to 0: 100 (weight ratio). When the acid value is 0 mg · KOH / g (Sample No. 1), gelation of the ceramic paint can be prevented, but the shape retention of the obtained green sheet is remarkably deteriorated. Could not be formed. Further, when the ratio of the component constituting the acid value of the curable acrylic resin to the component not substantially constituting the acid value is 10:90 (weight ratio) and the acid value is 20 mg · KOH / g ( Sample number 4), the ceramic paint gelled, and a green sheet could not be formed. On the other hand, the ratio of the component constituting the acid value of the curable acrylic resin and the component not substantially constituting the acid value is within the scope of the present invention, and the acid value is in the range of 2 to 10 mg · KOH / g. (Sample Nos. 2 and 3), while effectively preventing gelation of the ceramic paint, while maintaining good shape retention of the resulting green sheet, while preventing sheet attack, It was confirmed that it could be reduced.

  Moreover, when Mw of the curable acrylic resin as a binder was less than 50,000 (sample number 11), there was a problem with the sheet strength when it was made into a sheet, and short circuit failure could not be evaluated. When Mw exceeded 500,000, the resin could not be prepared (Sample No. 14).

  When Tg of the curable acrylic resin used as the binder was less than 0 ° C. (Sample No. 21), the shape retention of the obtained green sheet was deteriorated, and a green chip could not be formed. Moreover, when it exceeded 50 degreeC (sample number 24), the shape retention of the obtained green sheet deteriorated remarkably, and the green chip could not be formed.

  Even if the content of the curable acrylic resin in the dielectric layer paste is too small (Sample No. 31) or too much (Sample No. 33), the shape retaining property at the time of forming into a sheet is significantly deteriorated, A green chip could not be formed.

Even if the isoelectric point of BaTiO ₃ used was too low (sample number 41) or too high (sample number 42), the result was that the ceramic paint gelled.

  When the heating temperature when the curable acrylic resin is reacted is out of the range of the present invention (Sample Nos. 51 and 53), when the temperature when drying the green sheet is out of the range of the present invention (Sample No. 61, 63) and when the amount of the solvent contained in the ceramic paint is out of the scope of the present invention (Sample Nos. 71 and 72), the shape-retaining property at the time of forming into a sheet is remarkably deteriorated. A chip could not be formed.

Example 3
Instead of a thermosetting curable acrylic resin, an ultraviolet curable curable acrylic resin is used instead of 5 parts by weight of a thermal polymerization initiator, and a benzophenone compound as a UV polymerization initiator (trade name, manufactured by Nippon Carbide Corporation). SD-0314) A ceramic paint, a green sheet, a green chip sample, and a green paint sample were used in the same manner as in Examples 1 and 2 except that 1 part by weight was used and the curing conditions of the curable acrylic resin were changed as follows. A capacitor sample was prepared and the same measurement was performed.

The curable acrylic resin is cured by passing the lower green sheet and the intermediate green sheet through an ultraviolet treatment furnace.
Processing temperature: room temperature,
Irradiation dose: See Table 2 (unit: mJ / cm ² ),
Irradiation time: 5 seconds,
This was performed by irradiating with ultraviolet rays under the conditions of

  Further, in Example 3, as the ultraviolet curable curable acrylic resin, as the curable acrylic resin, acrylic acid is used as a component constituting the acid value, and the component that does not substantially constitute the acid value. The curable acrylic resin produced by using methyl methacrylate was used.

なお、表２中、酸価構成成分の比率は、「酸価を構成する成分の比率／実質的に酸価を構成しない成分」を重量比で表した。

In Table 2, the ratio of the acid value constituents is expressed by the weight ratio of “the ratio of the components constituting the acid value / the component not substantially constituting the acid value”.

Evaluation 2
From the results of Sample Nos. 101 to 124 in Table 2, it can be confirmed that the same results can be obtained when an ultraviolet curable curable acrylic resin is used instead of the thermosetting curable acrylic resin.

  Further, even if the ultraviolet irradiation dose is too small (Sample No. 151) or too much (Sample No. 152), the shape-retaining property at the time of forming into a sheet is remarkably deteriorated, and a green chip can be formed. There wasn't.

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor element main body 2 ... Interlayer dielectric layer 2a ... Outer dielectric layer 3 ... Internal electrode layer 4 ... External electrode

Claims (14)

  A ceramic paint for forming a green sheet comprising a ceramic raw material, a curable acrylic resin having an acid value in the range of 2 to 10 mg · KOH / g, and a solvent. Containing a ceramic raw material, a curable acrylic resin, and a solvent,
The curable acrylic resin has a weight ratio of a component constituting an acid value and a component that does not substantially constitute an acid value (component constituting an acid value: component not substantially constituting an acid value) = A ceramic paint for forming a green sheet contained in a range of 1:99 to 5:95.   The component constituting the acid value is a (meth) acrylic acid monomer unit, and the component not substantially constituting the acid value is a (meth) acrylic acid ester monomer unit. Ceramic paint.   The ceramic paint according to any one of claims 1 to 3, wherein the curable acrylic resin has a weight average molecular weight (Mw) of 50,000 to 500,000.   The ceramic paint according to any one of claims 1 to 4, wherein the curable acrylic resin has a glass transition temperature (Tg) of 0 to 50C.   The ceramic paint according to any one of claims 1 to 5, wherein the curable acrylic resin is contained in an amount of 6 to 12 parts by weight (excluding 12 parts by weight) with respect to 100 parts by weight of the ceramic raw material.   The ceramic paint according to any one of claims 1 to 6, wherein the solvent is contained in an amount of 200 to 300 parts by weight with respect to 100 parts by weight of the ceramic raw material. The curable acrylic resin is a thermosetting acrylic resin, and
The ceramic paint according to any one of claims 1 to 7, further comprising a thermal polymerization initiator for curing the thermosetting acrylic resin. The curable acrylic resin is an ultraviolet curable acrylic resin, and
The ceramic paint according to claim 1, wherein the ceramic paint further contains an ultraviolet polymerization initiator for curing the ultraviolet curable acrylic resin. Forming a green sheet using the ceramic paint according to claim 1;
Drying the green sheet;
Reacting the curable acrylic resin contained in the green sheet after drying to cure the green sheet;
Applying an internal electrode layer paste on the surface of the cured green sheet to form an internal electrode pattern;
Laminating the green sheet on which the internal electrode pattern is formed to obtain a green chip;
And a step of firing the green chip. Forming a green sheet using the ceramic paint according to claim 8;
Drying the green sheet;
Heating the green sheet after drying at a temperature of 80 to 100 ° C. (excluding 100 ° C.);
Applying a paste for an internal electrode layer on the surface of the green sheet after heating, and forming an internal electrode pattern;
Laminating the green sheet on which the internal electrode pattern is formed to obtain a green chip;
And a step of firing the green chip. Forming a green sheet using the ceramic paint according to claim 9;
Drying the green sheet;
With respect to the green sheet after drying, irradiating with ultraviolet rays of 50 to 500 mJ / cm ² (however, excluding 500 mJ / cm ^2),
Applying a paste for an internal electrode layer on the surface of the green sheet after ultraviolet irradiation, and forming an internal electrode pattern;
Laminating the green sheet on which the internal electrode pattern is formed to obtain a green chip;
And a step of firing the green chip.   The method for producing a multilayer electronic component according to any one of claims 10 to 12, wherein a drying temperature in forming the green sheet is 50 to 100 ° C (excluding 100 ° C). The method for producing a multilayer electronic component according to claim 10, wherein the green sheet after drying has a thickness of 3 μm or less.

Images