JP2002208534A - Method of manufacturing water-based electrode ink and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method of manufacturing water-based electrode ink for manufacturing electronic components, and that of the electronic components. SOLUTION: In the electrode ink whereat least two types of members out of nickel powder, nickel compound powder, or a nickel alloy are added into water or water-based organic solvent, nickel ink where nickel powder whose particle diameter is equal to or less than 1 μm is dispersed by 10 wt.% or more and 70 wt.% or less in water-based electrode ink and water or water-based organic solvent where the average particle diameter of the nickel powder is 1 μm or less and that of the nickel compound powder is 1 μm or less or viscosity is 10 Ps or less at a slip speed of 1000/sec while being in colloid state or being dissolved, an resin ink drops 11a and 11b where resin is dispersed or dissolved into water or water-soluble organic solvent by 0.1 wt.% or more and 100 wt.% or less are injected onto the same ceramic green sheet 5 or ceramic raw laminated from a plurality of different printer heads 8 for forming a specific electrode pattern 7 and then for forming a lamination external electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing ceramic electronic components used for manufacturing various electronic devices such as multilayer ceramic capacitors, LC filters, composite high-frequency electronic components, etc., mainly using gravure printing or ink jet printing. The present invention relates to an aqueous electrode ink and a method for producing an electronic component.

[0002]

2. Description of the Related Art Conventionally, ceramic electronic components such as a multilayer ceramic capacitor and various circuit boards have been prepared by printing a predetermined electrode pattern on a ceramic green sheet on a ceramic substrate such as an alumina substrate and laminating a plurality of such patterns. It is obtained by baking later.

Conventionally, electrode patterns have often been created by a screen printing method. However, when the number of printings increases, the printing accuracy decreases, and since the printing speed is as slow as 1 to 2 m / min,
New printing methods and electrode inks have been desired. For example, Japanese Unexamined Patent Publication (Kokai) No. 58-50795 proposes forming a conductor and a resistor on an unfired ceramic green sheet using an ink jet apparatus. Japanese Patent Application Laid-Open No. 8-222475 proposes a method of manufacturing a thick-film electronic component in which an electrode is formed from a thick-film ink using an ink jet apparatus. Also, JP-A-11-102834
In Japanese Patent Laid-Open Publication No. H10-163, an aqueous ink for an internal electrode of a multilayer ceramic capacitor is proposed. Therefore, the inventors made various trials of electrode inks for ink jets, and found that the lower the viscosity of the ink, the greater the problem of powder aggregation.

[0004] Therefore, the present inventors consider that the cause of such aggregation is as follows.
Various analyzes were attempted to determine if there was a cause on the surface of the powder. First, several types of nickel powder used for multilayer ceramic capacitors were selected as representative examples of base metal materials. When analyzed by a surface analyzer such as ESCA or SIMS, it was found that the surface of the nickel powder was commonly covered with oxide and adsorbed water with a thickness of several nm. The result will be described with reference to FIG. FIG.
In (A), 1a is a nickel powder having a particle size of 0.1.
It is about 1 to 0.6 μm. 2a is an adsorption layer. FIG. 3B illustrates the nickel surface in more detail. An adsorption layer 2b made of H ₂ O, NiO, or the like is formed on the surface of the nickel powder 1b, and pure nickel metal is not exposed. Not observed. Thus, it was confirmed that the surface of the commercially available nickel powder was covered with oxide or adsorbed water, and pure metallic nickel was not exposed. Based on this result, we asked a nickel powder manufacturer to deliberately oxidize the surface of the nickel powder at the time of shipment, thereby stabilizing the Ni powder and preventing self-heating, ignition, or dust explosion due to oxidation. It is said that there is. In addition, since water is always used in the nickel powder manufacturing process, apart from whether or not this water becomes absorbed water, it is not possible to manufacture nickel powder at low cost without water.
Therefore, we tried to remove the adsorbed water, but such adsorbed water is strongly adsorbed on the nickel surface as introduced in general literature, so it cannot be removed by drying at 100 ° C. It could only be removed by heating to a few hundred degrees in a vacuum, and it was considered difficult to remove the adsorbed water.

[0005] The nickel electrode ink used in conventional screen printing has a high viscosity, so that there is no particular problem even with such an adsorption layer. However, if you try to dilute this and use it for gravure printing or ink jet printing,
Inevitably, the nickel powders tend to aggregate. Further, in the case of a multilayer ceramic capacitor, it is desired to reduce the thickness of the internal electrodes, and recently, finer nickel powder has been used. However, as a matter of course, the finer the nickel powder, the easier the powder to agglomerate. Further, as the nickel powder becomes finer, the oxidation of nickel starts at a lower temperature, so that nickel is oxidized and lost during firing. Therefore, Japanese Patent Application Laid-Open Nos. 8-148372 and 11-1
JP 24607, JP-A-11-124606,
JP-A-11-172306, JP-A-2000-28
No. 2102, Japanese Patent Application Laid-Open No. 2000-178602,
JP-A-2000-1224058, Patent No. 29922
No. 70 and the like have proposed that oxides and other metals are formed on the surface of various nickel particles as such a measure. However, performing such a surface treatment also causes the powders to agglomerate with each other. Therefore, even if it is possible to match the thermal expansion coefficients of the electrode portion and the ceramic portion, it is necessary to reduce the thickness of the internal electrode. Was difficult.

As described above, it has been found that the occurrence of agglomeration is caused by the powder adsorption layer.

[0007]

However, in such a conventional manufacturing method, it was difficult to prevent agglomeration caused by the adsorption layer.

[0008] In order to solve such problems, the present invention addresses the surface modification of nickel powder, and devises the composition and manufacturing method of the multilayer ceramic aqueous electrode ink to provide a more practical ink and electronic component manufacturing method. The purpose is to provide. As a result, stable manufacturing can be achieved at lower cost.

[0009]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention proposes a low-viscosity aqueous electrode ink which hardly forms aggregates and a method for producing an electronic component using the same. . This makes it possible to prevent the aggregation of nickel powder, nickel compounds, and oxide compounds in low-concentration ink, which was previously impossible, so that stable gravure printing and ink jet printing can be performed. Cost reduction can be realized. In addition to conventional nickel powder, various surface treatments of nickel powder and sintering inhibitors such as nickel compounds and oxide compounds can be made into ink with higher dispersibility. The electrodes can be made thinner and more uniform, and high performance products can be provided to the market.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention relates to an electrode ink in which at least two kinds of members of nickel powder and nickel compound powder or nickel alloy are added to water or a water-soluble organic solvent, An aqueous electrode ink having an average particle size of the nickel powder of 1 μm or less, and an average particle size of the nickel compound powder of 1 μm or less or in a colloidal state or dissolved, and having a viscosity of 10 poise or less at a shear rate of 1000 / sec. The use of water or a water-soluble organic solvent in the electrode ink enhances safety, and the average particle size of both nickel and nickel compound powder is 1 μm.
By dispersing as follows, it is possible to prevent the generation of agglomerates even in a low-viscosity region where the viscosity is 10 poise or less at a shear rate of 1000 / sec, which was conventionally easy to coagulate,
This has the effect that the internal electrodes of a multilayer ceramic capacitor and the like can be made thinner, and furthermore, a compact and high-performance ceramic electronic component can be provided at low cost.

According to a second aspect of the present invention, there is provided a method for preparing a nickel powder having an average particle diameter of 1 μm or less and a nickel compound or nickel alloy emulsified and dispersed with an average particle diameter of 2 μm or less in water or a water-soluble organic solvent. An aqueous electrode ink having a viscosity of 10 poise or less at a shear rate of 1000 / sec, in which at least two kinds of members are added in a total amount of 10 wt% to 70 wt%, emulsifying a nickel compound with an average particle size of 2 μm or less. By dispersing, shear speed 1000
It is possible to prevent the generation of aggregates even in a low-viscosity region where the viscosity is 10 poise / second or less in the past, and the internal electrodes of a multilayer ceramic capacitor and the like can be made thinner. This has the effect that ceramic electronic components with high performance can be provided at low cost.

According to a third aspect of the present invention, a total of 10% by weight of an oxide compound in which a base metal powder or a base metal alloy powder is emulsified and dispersed in water or a water-soluble organic solvent with an average particle size of 2 μm or less. % Is an aqueous electrode ink having a viscosity of 10 poise or less at a shear rate of 1000 / sec added at a shear rate of 1000 / sec.
Even in a low-viscosity region where the viscosity is 10 poise or less at 0 / sec, which is conventionally easy to agglomerate, the generation of agglomerates can be prevented, the internal electrodes of multilayer ceramic capacitors and the like can be made thinner, and the size can be further reduced. This has the function of providing high-performance ceramic electronic components at low cost.

According to a fourth aspect of the present invention, at least one of the nickel powder and the nickel compound powder has a specific surface area of 1 square m / g or more, and the surface thereof has an anion or cation or 0.1% by weight of nonionic resin or dispersant on the surface of the powder
An aqueous electrode ink having a viscosity of 10 poise or less at a shear rate of 1000 / sec, which is adsorbed or added at a rate of not less than 30% by weight or less, and conventionally has a viscosity of 10 poise or less at a shear rate of 1000 / sec, and has conventionally been easily aggregated. Even in the low-viscosity region, it is possible to prevent the formation of aggregates by adsorbing a resin or dispersant, making it possible to reduce the thickness of the internal electrodes of multilayer ceramic capacitors, etc. Can be provided at low cost.

According to a fifth aspect of the present invention, there is provided a method for controlling a shear rate in which nickel powder and a nickel compound powder are dispersed in water or a water-soluble organic solvent together with a water-soluble resin or a latex resin having a particle size of 2 μm or less. An aqueous electrode ink with a viscosity of 10 poise or less at 1000 / sec. By adding a resin to the ink, it is possible to adjust the binding strength, adhesive strength, strength, etc. of the ink. It has an effect that a high-performance ceramic electronic component can be provided at low cost.

The invention according to claim 6 of the present invention is the aqueous electrode ink according to any one of claims 1 to 5, wherein the dissolved oxygen in water or the water-soluble organic solvent is less than 5 mg / liter or 5 ppm. By reducing the amount of dissolved oxygen in nickel, nickel and nickel compounds can be prevented from oxidizing in the ink and the formation of aggregates can be prevented, and the internal electrodes of multilayer ceramic capacitors can be made thinner and more compact This has the function of providing high-performance ceramic electronic components at low cost.

According to a seventh aspect of the present invention, there is provided a nickel ink in which nickel powder having a particle size of 1 μm or less is dispersed in water or a water-soluble organic solvent in an amount of 10 to 70% by weight, Alternatively, the resin is 0.1% in a water-soluble organic solvent.
A resin ink dispersed or dissolved in a weight percentage of 100% by weight or less forms a predetermined electrode pattern on a ceramic green sheet or a ceramic green laminate from a plurality of different printer heads, and is then laminated in a predetermined shape and cut. It is a method of manufacturing an electronic component that is formed and fired to form an external electrode.Even if the nickel ink and the resin easily react to form an aggregate, they are ejected from separate printer heads, and are ejected on a printing medium. To mix with each other for the first time,
Since no aggregates are formed in the printer head, various electronic components can be manufactured stably by the ink jet method.
It has the effect of being able to provide a small, high-performance ceramic electronic component at low cost.

The invention according to claim 8 of the present invention relates to a nickel ink in which nickel powder having a particle size of 1 μm or less is dispersed in water or a water-soluble organic solvent in an amount of 10% by weight or more and 70% by weight or less, Alternatively, a nickel compound ink obtained by dispersing or dissolving a nickel compound in a water-soluble organic solvent in an amount of 1% by weight or more and 70% by weight or less is provided on a ceramic green sheet or a ceramic green laminate from a plurality of different printer heads by a predetermined electrode pattern. After forming, is a method of manufacturing an electronic component that is laminated in a predetermined shape, cut, fired, and forms an external electrode, even if the nickel ink and the nickel compound react easily to form an aggregate.
Since they are ejected from separate printer heads and mix with each other for the first time on the printing medium, no agglomerates are formed in the printer head. It has the effect that electronic components can be provided at low cost.

Hereinafter, embodiments of the present invention will be described.

Embodiment 1 In Embodiment 1, an electrode ink composed of a nickel powder and a nickel compound powder in water or a water-soluble organic solvent will be described. Commercial concentration 10
% Nickel oxide aqueous colloid solution was prepared. This aqueous colloidal solution of nickel oxide has a particle size of 0.1 μm in water.
Of fine particles of nickel oxide having a concentration of 10% using a dispersant. This aqueous colloid solution was undiluted (10%) and diluted (1%, 0.1%) and observed. After 3 months, no precipitation occurred, and a commercially available 1 μm
Filtration was also easily performed using a filter (this confirmed that aggregates of 1 μm or more did not occur even after 3 months). Next, a commercially available nickel powder having a particle size of 0.2 μm is added to the colloid solution, and a dispersant or a resin is added and dispersed as needed, to give a viscosity of 2 poise at a shear rate of 1000 / sec. A 60% by weight aqueous electrode ink was prepared. The prepared aqueous electrode ink is directly dispersed on a dielectric powder mainly composed of barium titanate with a resin mainly composed of butyral resin, and coated on a ceramic green sheet (thickness: 5 μm). Direct printing was performed using a gravure printing machine, 400 layers of this were laminated, cut into a predetermined shape, and fired to produce a prototype multilayer ceramic capacitor. The yield of this prototype (referred to as prototype 1) was as high as 95% or more.

For comparison, a commercially available organic solvent-based nickel screen ink (viscosity: 200 poise, nickel concentration: 60% by weight) was diluted with butyl acetate (since gravure electrode ink is not commercially available). Was directly gravure-printed on the above-mentioned ceramic green sheet (5 μm thick), 400 layers were laminated, cut into a predetermined shape, and fired to produce a prototype multilayer ceramic capacitor. This prototype (referred to as prototype 2) was all short-circuited and yield was zero. Therefore, in order to prevent short-circuiting, the ceramic raw sheet was replaced with a 10 µm thick raw sheet, and the number of layers was reduced to 50 layers, and the prototype was reduced. The yield was finally improved to 20%. Was not.

These manufacturing methods are described in JP-A-11-8156, JP-A-8-316090, JP-A-9-162066, and JP-A-11-97.
No. 285, etc., the lamination method proposed by the inventors can be used.

As the nickel compound powder, besides nickel oxide, nickel acetate, nickel ammonium sulfate, nickel benzoate, nickel boride, nickel bromide, nickel carbonate, nickel citrate, nickel oxalate,
Nickel nitrate, nickel hydroxide (Ni (OH) ₂ ), nickel monoxide (NiO), nickel trioxide (Ni
₂ O ₃ ), nickel trioxide (Ni ₃ O ₄ ), nickel dioxide (NiO ₂ ), or the like may be used. Nickel chloride, nickel hydroxide, nickel nitrate, etc. are toxic and are not desirable to use. Nickel titanate (N
iFe ₂ O ₄ ), nickel vanadate (NiVO ₆ ), nickel phosphate (Ni ₂ P, Ni ₃ P, Ni ₃ (PO ₄ ) ₂ ), etc., adjust the sintering start temperature of nickel itself. it can.

It is desirable that the nickel compound part be 1 part by weight or more and 200 parts by weight or less based on 100 parts by weight of nickel. If the amount of the nickel compound added is 0.5 part by weight or less, the effect of addition may not be obtained. If the amount of the nickel compound powder exceeds 300 parts by weight, the firing may become unstable.

The average particle diameter of the nickel powder is desirably 1 μm or less (especially, when the internal electrode is made as thin as 1 μm or less, a nickel powder having an average particle diameter of about 0.1 μm to 0.3 μm is desirable). . Average particle size of nickel powder is 3μm
In the above case, large aggregates of several μm or more contained in the electrode ink may reduce the reliability of the product. In particular, when high lamination is required, the aqueous electrode ink should be 5 μm or 2 μm
It is desirable to remove the aggregates by filtration with a filter described above. In order to perform such filtration, the average particle size of the nickel powder is desirably 0.5 μm or less, and preferably around 0.2 μm.

Similarly, the average particle size of the nickel compound powder is 2 μm.
m or less is desirable. Average particle size of nickel compound powder is 3μ
When the average particle size is more than m, large aggregates of several μm or more contained in the electrode ink may lower the reliability of the product. In particular, when high lamination is required, the aqueous electrode ink should be 5 μm or 2 μm.
It is desirable that the aggregates have been removed by filtration with a filter of m. In order to perform such filtration,
The average particle size of the nickel compound powder is desirably 0.5 μm or less, particularly preferably about 0.01 to 0.3 μm. When the water solubility (or hydrophilicity) of the nickel compound powder is high, it can be more uniformly dispersed or dissolved in the aqueous electrode ink by a treatment such as ionization, hydration, or colloidation.

When organic nickel or the like is used as the nickel compound, the organic nickel may be dissolved in an organic solvent, and this may be emulsified and dispersed in water in a kind of emulsion state using an emulsifier such as Poval. In particular, in the case of an internal electrode of a multilayer ceramic capacitor or the like, a thinner layer is required. Even when emulsified and dispersed, the average particle size is desirably 2 μm or less.

The total of the nickel powder and the nickel compound is preferably from 10% by weight to 70% by weight in terms of nickel, and more preferably from 20% by weight to 40% by weight. If the content is less than 5% by weight, the ink concentration is too low, which increases the production cost. When the content is 80% by weight or more, ink dispersion may be unstable.

(Embodiment 2) In Embodiment 2, a resin used for an aqueous electrode ink will be described. Particularly, in the aqueous electrode ink of the present invention, if there is no appropriate resin component, the electrode may be damaged or peeled off after printing. Therefore, it is desirable to add a water-soluble resin to the aqueous electrode ink of the present invention. Even a water-insoluble resin can be added as a resin to the aqueous electrode ink of the present invention by emulsification in water, that is, emulsification using various emulsifiers.

The water-soluble resin used in the present invention includes PV
Vinyl resins such as A (polyvinyl alcohol) and polyvinyl acetal resin, CMC (carboxymethylcellulose), MC (methylcellulose), HPC
Cellulose-based resins such as (hydroxypropylcellulose) and the like may be used in combination as necessary.
Even water-insoluble resins, for example, rubbers such as PVB (polyvinyl butyral) resin and NBR (nitrile butadiene rubber), can be emulsified using a suitable emulsifier to form the aqueous electrode ink of the present invention. , As a resin.

First, as a conventional example, Japanese Patent Application Laid-Open No. H11-102
A water-based electrode ink was prototyped using a general water-soluble resin with reference to Japanese Patent No. 834 and the like, and an attempt was made to print on a ceramic raw sheet by ink jet. Methylcellulose, hydroxyethylcellulose, polyvinyl alcohol and the like were used as the resin, and additives such as propylene glycol and diethylene glycol were further added, and a trial production was performed in the same manner. Unfortunately, however, the printer head was clogged in a few seconds, making continuous printing impossible. Therefore, this ink was set in a commercially available desktop gravure printing apparatus and printed as a water-based gravure ink, and a multilayer ceramic capacitor was prepared in the same manner as in the first embodiment. However, defects such as delamination may occur.

Therefore, a latex resin having an adhesive property (for example, a plasticizer added to polyvinyl butyral and emulsified in water with a particle size of 1 μm or less) is further added to the aqueous gravure ink, and a multilayer ceramic capacitor is similarly formed. As a result, no defect such as delamination occurred. As described above, by adding an emulsion such as PBV, NBR, or acrylic, or a latex resin, the adhesiveness of the aqueous electrode ink and the flexibility of the coating film can be significantly improved, thereby increasing the yield of the multilayer ceramic electronic component. .

When a water-soluble resin and an emulsion are mixed, they may react. In experiments conducted by the inventors, for example, gelation sometimes occurs when a nonionic resin is mixed with an emulsion resin emulsified with an anionic emulsifier.
As described above, when a plurality of resins are mixed, a gelling reaction due to ion association can be suppressed by using the same type of material as a nonionic type for a nonionic type, an anionic type for anionic type, and a cationic type for cationic type. In addition, when a dispersant is added to the water-soluble electrode ink of the present invention, if necessary, a nonionic dispersant and a nonionic water-soluble resin or emulsion may be used to improve the stability. High aqueous electrode ink can be manufactured. As a dispersant, it is desirable to add a carboxylic acid type, phosphoric acid, polyoxyethylene type, oleic acid or the like in the range of, for example, 0.5% by weight or more and 10% by weight of nickel or nickel compound powder. If the amount is 0.2% by weight or less, the dispersing effect may not be obtained. On the other hand, if the amount exceeds 20% by weight, the coating film may become hard or brittle, thereby lowering the strength of the coating film.

The non-volatile organic components (water-soluble resin, emulsion resin, dispersant, etc.) in the aqueous electrode ink proposed in the present invention comprise 0.1% by weight of the water-soluble nickel electrode ink.
It is desirable that the content be at least 20% by weight. If the amount is less than 0.05% by weight, the binding strength of the electrode ink coating film is insufficient, and the coating film may be peeled off. When the content is 25% by weight or more, although the binding strength of the coating film of the electrode ink is sufficient, defects such as delamination may occur upon firing.

The total concentration of nickel and nickel compound powder in the electrode ink proposed in the present invention is desirably from 10% by weight to 70% by weight. If the content is 5% by weight or less, the necessary internal electrode layer may not be formed after firing because the ink concentration is too low. On the other hand, when the content is more than 80% by weight, the ink concentration is too high and the ink is hardly leveled.
When a multilayer ceramic capacitor is made, it is difficult to make the internal electrodes thinner.

The average particle size of the emulsion is desirably 1 μm or less. When the average particle size is 3 μm, an emulsion having a size of 5 μm or more may be included, and such a large emulsion may cause a failure of the ink jet device or a failure after firing. In particular, in the case of an emulsion resin, the viscosity is low even at a high resin concentration as compared with a general water-soluble resin, so that the emulsion resin is effective as a binder resin for an ink jet. In an actual process, a more stable ink can be prepared by combining a general water-soluble resin and an emulsion.

(Embodiment 3) In Embodiment 3, a nickel slurry is used instead of a commercially available nickel powder.
A similar experiment was performed. When inquired of the nickel powder manufacturer about the nickel powder production method, if necessary, synthesize nickel powder in a vacuum, wash it, and dry it, or use nickel powder in a water or organic solvent. It has been found that there is a method for producing a nickel powder in which a nickel powder is synthesized by reducing a nickel compound, washed with water, and dried. Therefore, we ask each nickel powder maker to separate from the nickel powder manufacturing process before drying (that is, nickel powder immersed in water before and after washing) and add appropriate solvents and additives to this. Then, a treatment for preventing reaggregation and precipitation was performed to prepare an aqueous electrode ink. As described above, by using undried nickel powder as the nickel powder (without using a general dispersing device such as a three-roll mill or a meal mill), the aqueous electrode ink can be shortened with a high yield close to 100%. Created in time. This ink is 3 μm
Filtration was also easy. Even in this case, the average particle size of the nickel powder itself is desirably 1 μm or less. Even in the case of undried nickel powder, if the average particle size is 3 μm or more, the yield of the product may be reduced. In particular, in the case of high lamination, the aqueous electrode ink is desirably filtered with a 5 μm or 2 μm filter to remove aggregates. In order to perform such filtration, the average particle size of the nickel powder is desirably 0.5 μm or less, and preferably around 0.2 μm.

For further comparison, the particle diameter was 0.2 μm.
Similarly, an aqueous electrode ink was prepared using only the nickel powder, but the nickel powder sometimes re-agglomerated and precipitated in the ink. Therefore, when inkjet printing was performed using an aqueous electrode ink made only with 0.2 μm nickel powder,
The ink tends to be clogged in the printer head of the ink jet printer, and it is necessary to clean the printer head every few minutes (or replace the printer head itself with a new one). On the other hand, in the case of the ink containing the nickel compound powder, the nickel powder hardly re-agglomerated and did not precipitate even at a low viscosity.

For comparison, when an aqueous electrode ink was prepared using dried nickel powder using a three-roll mill or a bead mill, the yield was about 90%, and the dispersed state was such that filtration of 3 μm was possible. Required a fairly long dispersion. In addition, when an ink is to be prepared from nickel powder, the smaller the particle size, the more complicated the process for high dispersion, and the lower the yield. On the other hand, when undried nickel powder was used, the ink could be easily formed only by using a commercially available stirrer or ultrasonic disperser.
In addition, as the nickel powder becomes finer, it tends to fly in the air, which may deteriorate the working environment. However, by using undried nickel powder (nickel powder immersed in water) instead of nickel powder, the working environment can be improved without nickel flying in the air. in this way,
Even when a nickel slurry is used, the addition of a nickel compound makes it possible to stabilize the dispersion of the ink and to reduce the thickness of the inner electrode. The nickel powder or nickel slurry used here may be nickel powder or nickel slurry that has been subjected to various surface treatments on the manufacturer side. By performing the surface treatment in a more upstream process, it is possible to stabilize the quality and reduce the cost.

Embodiment 4 In Embodiment 4, the dissolved oxygen in the aqueous electrode ink will be described.

In the aqueous electrode ink, the lower the amount of dissolved oxygen in the water or the water-soluble organic solvent in which the nickel powder is dispersed, the better. Especially when dissolved oxygen is 7
g / liter or 7 ppm or a saturation value of 50
% Or more, the surface of the nickel powder may be oxidized and deteriorated in about one month. When the surface of the nickel powder thus oxidized is viewed with a scanning electron microscope, the surface is finely cracked or peeling. Also, the nickel powder whose surface is oxidized in this way has a low tap density,
It is unsuitable for internal electrodes of multilayer ceramic electronic components.
In order to prevent such oxidation, it is desirable to reduce dissolved oxygen to 1 mg / liter or less as much as possible. Also in the case of storing the nickel slurry, it is effective to prevent air bubbles and air bubbles from remaining inside and to fill the inside of the container with nitrogen or the like. Also, by reducing the dissolved oxygen, the electrode ink becomes less likely to rot. Also, by reducing dissolved oxygen, other dissolved gases (mainly nitrogen) can be reduced. In order to measure the dissolved oxygen in the ink, a commercially available dissolved oxygen meter may be used. Further, in a normal ink dispersion process using a ball mill or the like, dissolved oxygen tends to increase during ink preparation. In such a case, nickel or nickel compound powder is
It is preferable to use a commercially available dissolved oxygen removing device (for example, one using vacuum, ultrasonic waves, a permeable membrane, or the like) in a state of being dispersed below m.

In particular, when the present ink is used for an ink jet, the dissolved amount of nitrogen and the like in addition to oxygen must be suppressed to 1 mg / liter or less. 10ml of nitrogen or carbon dioxide
If more than 1 / liter is dissolved, bubbles may be generated in the head of the ink jet, making ink ejection unstable. Therefore, even when the electrode ink of the present invention is used in an ink jet apparatus, long-term printing stability can be obtained, and the yield of electronic components can be increased.

Embodiment 5 In Embodiment 5, an example in which the aqueous electrode ink described in Embodiment 1 or the like is applied to ink jet printing will be described with reference to FIG.

FIG. 1 shows the flow characteristics of the aqueous electrode ink proposed in the present invention.
Sec) and the Y axis is viscosity (unit is poise). In FIG. 1, an arrow 3 indicates a range of a viscosity of 0.01 poise to 10 poise at a shear rate of 1000 / sec. The dotted line 4a connects two points of 10 poise at a shear rate of 1000 / sec and 1000 poise at a shear rate of 10 / sec. The dotted line 4b indicates a viscosity of 0.01 poise regardless of the shear rate. When the aqueous electrode ink of the present invention is used in an ink jet, the dotted line 4a and the dotted line 4b
It is desirable that the ink viscosity falls within the viscosity range surrounded by.

In particular, at a shear speed of 1000 / sec, the value of 0.1.
In the case of a viscosity of less than 005 poise, in many cases, this viscosity range is reached only with water or a water-soluble organic solvent, so that a necessary amount of an additive such as nickel, nickel compound powder, and resin may not be added to the ink. Yes. In addition, if the viscosity exceeds 10 poise at a shear rate of 1000 / sec, depending on the ink jet device, the ink may not fly due to insufficient power, or the amount and direction of ejection of the ink may vary, and the printing accuracy required for electronic parts may be obtained. May not be possible. In addition, even when performing gravure printing, printing unevenness is likely to occur. Further, the optimum viscosity range for the ink jet is as follows.
At 0 / sec, a lower viscosity of 1 poise or less is desirable, but whether or not the ink can be actually ejected from the printer head cannot be determined only by the viscosity. In particular, when a piezo-type printer head is used, the stability of printing can be improved by reducing the dissolved oxygen in the ink. In particular, dissolved oxygen in the ink tends to form air bubbles in the printer head, and these air bubbles may cause printing instability.

(Embodiment 6) In Embodiment 6, an example in which the aqueous electrode ink described in Embodiment 1 or the like is applied to gravure printing will be described in more detail.

When the aqueous electrode ink proposed in the present invention is developed into an aqueous gravure ink, a shearing speed of 1000 /
In seconds, the viscosity is desirably from 0.1 poise to 10 poise. 50m when the ink viscosity is less than 0.1 poise
When printing at a high speed of more than / min, the ink may not be able to be carried over the gravure plate, and the printing quality may be degraded. When the ink viscosity is 20 poise or more, the transferability of the ink from the gravure plate to the printing medium is reduced, and pinholes are easily generated in the printed pattern.

The Ni concentration in the aqueous gravure ink is:
The content is desirably from 20% by weight to 80% by weight. When the content is less than 15%, the solvent component increases, and therefore, when high-speed printing at, for example, 30 m / min or more is to be performed, a drastic increase in the capacity of the dryer is required, which is not practical. If the solid content is 85% or more, it is difficult to lower the ink viscosity, and defects such as pinholes are likely to occur in the print pattern.

The gravure printing speed is desirably from 10 m / min to 500 m / min. If the printing speed is as low as 5 m / min, printing unevenness may occur rather than high-speed printing at 20 m / min or more. Printing speed is 600
If it exceeds m / min, the ink may be scattered due to the centrifugal force of the printing press, and the ceramic raw sheet or the like may be soiled, and the quality and yield of the product may be reduced.

(Embodiment 7) In Embodiment 7, a case will be described in which nickel powder obtained by subjecting nickel powder to ceramic processing is used. For example, in the case of a multilayer ceramic capacitor using nickel as an internal electrode, if the sintering properties of the nickel portion serving as the internal electrode and the ceramic portion serving as the dielectric do not match, a defect called delamination or the like occurs. there is a possibility. In particular, the smaller the particle size of nickel or nickel oxide, the lower the oxidation start temperature or sintering start temperature, so that the sinterability with the ceramic portion may not match. For example, when the particle size of nickel is about 0.6 μm,
Sintering starts at about 700 ° C.
When it is lowered to about 1 μm, sintering may start at about 300 to 400 ° C.

Therefore, in the embodiment, Japanese Patent No. 2992
No. 270, etc., a composite nickel fine powder surface-treated with a ceramic material (with a surface of TiO ₂ , M
nO ₂ , Cr ₂ O ₃ , Al ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , BaT
(i.e., a surface treatment of at least 0.1% by weight and at least 10% by weight of the nickel compound powder with at least one kind of material of iO ₃ ) is selected, and as shown in Embodiments 1 to 6, It has become.

An internal electrode pattern is formed on the green ceramic sheet (5 μm in thickness) formed by dispersing dielectric powder in butyral resin formed on a base film using ink jet or gravure printing technology. Direct printing was performed so as to form a thin layer, 300 layers were stacked, cut into chips, fired, and external electrodes were formed to produce a multilayer ceramic capacitor (referred to as a prototype in Mode 7). The yield of the prototype in this mode 7 is 95% or more. Further, the prototype in the mode 7 is filled with a resin, the cross section is observed with an electron microscope, and the thickness of the internal electrode is measured.
The thickness was 7 to 0.9 μm, and the film was formed uniformly without interruption (capacitance characteristics were 100% as designed).

In Comparative Example 1, the above-mentioned composite nickel fine powder was dispersed in a resin solution obtained by dissolving α-terpineol and ethyl cellulose using a three-roll mill to prepare a solvent-based screen ink. Using this ink, the internal electrodes were directly thin-layered on the green ceramic sheet (thickness: 10 μm) by screen printing (further adjusting the thickness of the screen plate to reduce the thickness of the internal electrodes). And then similarly laminate 300 layers, cut into chips,
The resultant was fired to form external electrodes, thereby producing a multilayer ceramic capacitor (referred to as Comparative Product 1 in Embodiment 7). This form 7
In Comparative Example 1, the total number was 20% or less (regardless of the difference in the thickness of the internal electrodes), and almost all were short-circuited.
This was thought to be because the α-terpineol contained in the electrode ink permeated the green ceramic sheet, resulting in a short circuit. An organic solvent other than α-terpineol was also examined, but short-circuits occurred frequently. Next, the comparative product 1 in this embodiment 7 was filled with a resin, and its cross section was observed with an electron microscope to measure the thickness of the internal electrode. In the sample aimed at thinning, the thickness of the internal electrode was as thin as 0.7 to 0.9 μm, but the internal electrode was cut off (the characteristic capacity was about 50% of the designed value. Was). The thickness of the internal electrode is 0.9-1.2 μm
In this case, the internal electrodes were continuous, but the thickness unevenness was large. This thickness unevenness was considered to be caused by traces of the mesh in the screen printing, re-melting of the ceramic raw sheet, and the like. As described above, it has been found that even if a composite nickel fine powder having improved oxidation resistance is used, the characteristics cannot be fully utilized unless the process can be optimized.

In Comparative Example 2, a conventional nickel powder (no ceramic was formed on the surface) was dispersed in a resin solution obtained by dissolving α-terpineol and ethylcellulose using a three-roll mill. Screen ink was made. Using this ink, the internal electrodes are directly printed on the ceramic raw sheet (thickness: 10 μm) so as to form a thin layer by screen printing.
The layers were laminated, cut into chips, fired, and external electrodes were formed to produce a multilayer ceramic capacitor (referred to as Comparative Product 2 of Embodiment 7). The yield of the comparative product of this embodiment 7 is 20% or less (regardless of the difference in the thickness of the internal electrode),
Most were short. This was thought to be because the α-terpineol contained in the electrode ink had permeated the ceramic raw sheet, resulting in a short circuit. An organic solvent other than α-terpineol was also examined, but short-circuits occurred frequently. Next, the comparative product 2 in this embodiment 7 was filled with a resin, and the cross section thereof was observed with an electron microscope to measure the thickness of the internal electrode. In the sample aimed at thinning,
When the thickness of the internal electrode was aimed at 0.7 to 0.9 μm, the internal electrode was almost completely eliminated (the characteristic capacitance was obtained at only 10% or less of the designed value). When the thickness of the internal electrode was 0.9 to 1.2 μm, the internal electrode was continuous, but the thickness unevenness was large. It was considered that the thickness unevenness was caused by traces of a mesh in screen printing, re-dissolution of the raw ceramic sheet, and the like. As described above, it was found that when nickel powder having low oxidation resistance was used, when the thickness was reduced, the internal electrodes suddenly disappeared, and as a result, a predetermined capacity could not be obtained.

Needless to say, the same effect can be obtained for nickel compound powder as well as nickel powder. As the nickel compound, an inorganic nickel compound may be used in addition to the organic nickel compound. The nickel alloy itself is a kind of nickel compound. For example, nickel alloy, NiCr, NiFe, NiCo, NiC
A nickel alloy such as u, NiTi may be used.

The surface treatment of an oxide such as TiO _{2 with} respect to nickel is desirably 0.1% by weight or more and 10% by weight or less of nickel. If the content is less than 0.05% by weight, the effect of addition may be small. If the amount exceeds 20% by weight, the capacity and characteristics may be affected. Further, by mixing a plurality of types of nickel powder, nickel compound powder, Ni powder surface-treated with TiO _{2 and the} like, and nickel compound powder surface-treated with TiO _{2 and the} like, it is possible to improve matching of firing at the time of high lamination.

In order to perform such a surface treatment, it is desirable that at least one of the nickel powder and the nickel compound powder has a specific surface area of 1 square m / g. In the case of a large nickel powder or the like having a specific surface area of 0.5 square m / g or less, the effect of preventing oxidation is small, and such a treatment may be rather expensive.

(Embodiment 8) In Embodiment 8, surface treatment of nickel powder or nickel compound powder will be described. By performing the surface treatment of the nickel or nickel compound powder, reaggregation of the powders can be prevented. As the surface treatment with an organic substance, resins such as anions, cations, and nonions, and dispersants can be used. Among them, phosphoric acid, polycarboxylic acid,
Fatty acids, polyoxyethylene resins and salts thereof can be used. If necessary, such a surface treatment as a kind of pretreatment is applied to nickel or nickel compound powder to improve the dispersibility and stability of the ink. By using such a treated powder, even when a dispersing device such as a three-roll or bead mill is used, the dispersing operation can be greatly reduced, the production efficiency can be increased, and the ink yield can be greatly improved.

The water used for the aqueous electrode ink is not tap water but may be distilled water, ion-exchanged water, pure water, or the like, which contains few impurities. As a water-soluble organic solvent, a defoaming effect can be obtained by adding a plurality of glycols such as ethylene glycol, propylene glycol, polyethylene glycol, and glycerin, and alcohols such as ethanol and decyl alcohol as necessary. In the case of ethylene oxides, the effects of both a water-soluble organic solvent and both a solvent and a dispersant can be obtained. The ratio of water to the water-soluble organic solvent is preferably 1 part by weight or more and 300 parts by weight or less with respect to 100 parts by weight of water. Since it is affected by drying conditions (drying temperature, air volume, printing speed) and the like desired for the electrode ink, it is desirable to increase or decrease as necessary.

Embodiment 9 In Embodiment 9, a method for manufacturing a multilayer ceramic electronic component using the aqueous electrode ink proposed in the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing a state in which a multilayer ceramic electronic component is manufactured using an ink jet apparatus. First, in FIG. 2, reference numeral 5 denotes a raw ceramic sheet, in which a plurality of internal electrodes 6 are formed. Reference numeral 7 denotes an electrode pattern for applying the first ink 9 and the second ink 10 set on the printer head 8 to external signals (not shown).
Thus, ink droplets 11a and 11b are respectively formed. The electrode pattern 7 is formed by these ink droplets 11a and 11b.

In the ninth embodiment, the first ink 9
And the second ink 10 are separately shot, so that the first ink 9 and the second ink 10 are not mixed in the printer head 8 to form an aggregate or the like. For example, when nickel powder is dispersed with a nonionic adsorbent to form an ink and a nickel compound is dispersed with a cationic system to form an ink, when mixed together, the nonion and the cation react to form an aggregate. is there. In such a case, aggregation can be prevented by setting nonionic and cationic inks in the first ink 9 and the second ink 10 of the printer head 8. In such a case, in addition to the nonion and the cation, the anion and the cation, the cation and the nonion, or the nonions can be prevented from aggregating with each other. Generally, it is difficult to disperse nickel and a nickel compound with the same additive. In this case, as described in the ninth embodiment, by printing separately, aggregation can be prevented.

It is to be noted that base metal powder such as copper or base metal alloy powder can be used instead of nickel powder.

As the nickel compound, nickel powder obtained by adsorbing various ceramic members or the like on nickel powder may be used. As described above, even if the surface properties of the ceramic member change, different surface treatments can be performed accordingly. For this reason, Ni is proposed in Japanese Patent Application Laid-Open No. H11-124606.
And a CuN alloy, JP-A-11-343501, JP-A-2000-178601, and JP-A-2000-21.
Proposed in 2609 JP etc. The TiO ₂ and MnO ₂ other surface coated Ni powder, JP 2000-45002 and JP 2000-169904 JP proposed oxygen content is low nickel powder in such, JP 2000-1786A
Even with nickel powder or the like having a spinel layer formed on the surface proposed in Japanese Patent Application Publication No. 02-2002 or the like, an electrode ink with reduced generation of aggregates can be realized, and a high-performance electronic component can be manufactured at low cost.

[0064]

As described above, by the method of manufacturing an aqueous electrode ink and an electronic component proposed in the present invention, a ceramic electronic component such as a multilayer ceramic capacitor having a base metal as an internal electrode can be manufactured at a higher yield and at a lower cost. The effect that it can be provided to the user is obtained.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing flow characteristics of an aqueous electrode ink according to Embodiment 5 of the present invention.

FIG. 2 is a schematic diagram showing a state in which a multilayer ceramic electronic component according to a ninth embodiment of the present invention is manufactured using an ink jet apparatus.

FIG. 3 is a cross-sectional view for explaining a cross-sectional shape of a nickel powder in a conventional example.

[Explanation of symbols]

 1a, 1b Nickel powder 2a, 2b Adsorption layer 3 Arrow 4a, 4b Dotted line 5 Ceramic raw sheet 6 Internal electrode 7 Electrode pattern 8 Printer head 9 First ink 10 Second ink 11a, 11b Ink droplet

Continuation of front page (72) Inventor Masaaki Katsumata 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. AD11 AD15 BA06 BA07 BA12 BA14 BE22 CA03 CA06 DA01 DA02 EA44 FA07 GA24 GA34 5E001 AB03 AC09 AJ01

Claims (8)

[Claims] 1. An electrode ink in which at least two members of nickel powder and a nickel compound powder or a nickel alloy are added to water or a water-soluble organic solvent, wherein the average particle diameter of the nickel powder is 1 μm or less, and An aqueous electrode ink having a nickel compound powder having an average particle diameter of 1 μm or less, or in a colloidal state or dissolved, and having a viscosity of 10 poise or less at a shear rate of 1000 / sec. 2. A total of at least two members of nickel powder having an average particle diameter of 1 μm or less and a nickel compound or nickel alloy emulsified and dispersed with an average particle diameter of 2 μm or less in water or a water-soluble organic solvent. An aqueous electrode ink having a viscosity at a shear rate of 1000 / sec and a viscosity of 10 poise or less, added in an amount of from 70 wt% to 70 wt%. 3. A total of not less than 10% by weight of a base metal powder or a base metal alloy powder in water or a water-soluble organic solvent together with an oxide compound emulsified and dispersed with an average particle size of 2 μm or less.
An aqueous electrode ink having a viscosity at a shear rate of 1000 / sec and a viscosity of 10 poise or less, added in an amount of not more than 10% by weight. 4. A specific surface area of at least one of nickel powder and nickel compound powder is 1 square m /
g or more, and the surface has an anionic or cationic or nonionic resin or dispersant adsorbed or added to the surface of the powder at a ratio of 0.1% by weight or more and 30% by weight or less. An aqueous electrode ink having a viscosity of 10 poise or less at 1000 / sec. 5. Nickel powder and nickel compound powder in water or a water-soluble organic solvent are water-soluble resin or 2 μm in particle size.
An aqueous electrode ink having a viscosity of 10 poise or less at a shear rate of 1000 / sec, which is dispersed together with the following latex resin. 6. The aqueous electrode ink according to claim 1, wherein dissolved oxygen in water or a water-soluble organic solvent is less than 5 mg / liter or 5 ppm. 7. A particle having a particle size of 1 μm in water or a water-soluble organic solvent.
m and a nickel ink in which 10% to 70% by weight of nickel powder is dispersed, and 0.1% to 100% by weight of a resin dispersed or dissolved in water or a water-soluble organic solvent. A resin ink is sprayed from a plurality of different printer heads onto the same ceramic green sheet or ceramic green laminate to form a predetermined electrode pattern, then laminated in a predetermined shape, cut, and fired to form external electrodes. Manufacturing method of electronic components. 8. A particle having a particle size of 1 μm in water or a water-soluble organic solvent.
and a nickel ink in which a nickel compound is dispersed or dissolved in water or a water-soluble organic solvent in an amount of 1 to 70% by weight in water or a water-soluble organic solvent. Manufacturing of electronic components in which a compound ink is formed into a predetermined shape on a ceramic green sheet or ceramic green laminate from a plurality of different printer heads, then laminated, cut, and fired to form external electrodes. Method.