TWI868243B - Conductive slurry for gravure printing, electronic components, and multilayer ceramic capacitors - Google Patents

Abstract

The present invention provides a conductive slurry for gravure printing that can reduce the waviness of the surface of a dried film. The conductive slurry for gravure printing contains conductive powder, ceramic powder, dispersant, binder resin and organic solvent, wherein the organic solvent contains at least one terpene solvent selected from the group consisting of terpineol, dihydroterpineol and dihydroterpineol acetate.

Description

Conductive slurry for gravure printing, electronic components, and multilayer ceramic capacitors

The present invention relates to conductive slurry for gravure printing, electronic components and multilayer ceramic capacitors.

As electronic devices such as mobile phones and digital devices become smaller and more powerful, electronic components such as multilayer ceramic capacitors are also expected to be smaller and have higher capacity. Multilayer ceramic capacitors have a structure in which multiple dielectric layers and multiple internal electrode layers are alternately stacked, and miniaturization and higher capacity can be achieved by thinning these dielectric layers and internal electrode layers.

For example, a laminated ceramic capacitor can be manufactured as follows. First, a conductive slurry for an internal electrode is printed in a predetermined electrode pattern on the surface of a ceramic green sheet containing a dielectric powder such as barium titanium oxide (BaTiO ₃ ) and a binder resin, and dried to form a dry film. Then, the dry film and the ceramic green sheet are laminated in an alternating manner to obtain a laminate. Then, the laminate is heated and pressed to form a press-bonded body. The press-bonded body is cut, subjected to an organic binder removal treatment in an oxidizing environment or an inert environment, and then fired to obtain a fired chip. Next, external electrode slurry is applied to both ends of the fired wafer, and after firing, nickel or the like is plated on the surface of the external electrode to obtain a multilayer ceramic capacitor.

As a printing method used when printing conductive paste on dielectric green sheets, screen printing has been generally used in the past. However, in view of the requirements for miniaturization, thin filmization and improved productivity of electronic devices, it is sought to print finer electrode patterns with higher productivity.

As one of the printing methods of conductive slurry, gravure printing is proposed as a continuous printing method in which the conductive slurry is filled in the recessed parts provided on the plate and the plate is pressed against the printed surface to transfer the conductive slurry from the plate. The gravure printing method has a high printing speed and excellent productivity. When using the gravure printing method, it is necessary to appropriately select the binder resin, dispersant, solvent, etc. in the conductive slurry and adjust the properties such as viscosity to a range suitable for gravure printing.

For example, Patent Document 1 describes a conductive slurry for forming an internal conductor film by gravure printing, wherein the internal conductor film is an internal conductor film in a laminated ceramic electronic component having a plurality of ceramic layers and an internal conductor film extending along a specific interface between the ceramic layers; the conductive slurry comprises 30 to 70 wt % of a solid component containing metal powder, 1 to 10 wt % of an ethyl cellulose resin component having an ethoxy content of 49.6% or more, 0.05 to 5 wt % of a dispersant and a solvent component as the remainder, and has a viscosity η _0.1 of 1 Pa at a shear rate of 0.1 (s ^-1 ). s or more and a viscosity η _0.02 at a shear rate of 0.02 (s ^-1 ) that satisfies the conditions represented by a specific formula.

In addition, Patent Document 2 describes a conductive slurry, which is also a conductive slurry for forming an internal conductive film by gravure printing, similarly to Patent Document 1, and comprises 30 to 70% by weight of a solid component containing metal powder, 1 to 10% by weight of a resin component, 0.05 to 5% by weight of a dispersant, and a solvent component as the remainder, and is a thixotropic fluid having a viscosity of 1 Pa.s or more at a shear rate of 0.1 (s ^-1 ), and a viscosity change rate of 50% or more at a shear rate of 10 (s ^-1 ) based on the viscosity at a shear rate of 0.1 (s ^-1 ).

According to the above-mentioned patent documents 1 and 2, the conductive slurry is a thixotropic fluid with a viscosity of 1 Pa.s or more at a shear rate of 0.1 (s ^-1 ), and can obtain stable continuous printing at high speed in gravure printing, and can manufacture multilayer ceramic electronic parts such as multilayer ceramic capacitors with good production efficiency.

In addition, Patent Document 3 describes a conductive slurry for gravure printing, which is a conductive slurry for internal electrodes of a multilayer ceramic capacitor containing a conductive powder (A), an organic resin (B), an organic solvent (C), an additive (D), and a dielectric powder (E); the organic resin (B) is composed of polyvinyl butyral having a polymerization degree of 10,000 to 50,000 and a weight average molecular weight of 10,000 to 50,000. The conductive slurry is composed of 10,000 to 100,000 ethyl cellulose; the organic solvent (C) is composed of any one of propylene glycol monobutyl ether, a mixed solvent of propylene glycol monobutyl ether and propylene glycol methyl ether acetate, or a mixed solvent of propylene glycol monobutyl ether and mineral spirits; the additive (D) is composed of a separation inhibitor and a dispersant, and the separation inhibitor is composed of a composition containing a polycarboxylic acid polymer or a polycarboxylate. According to patent document 3, the conductive slurry has a viscosity suitable for gravure printing, can improve the uniformity and stability of the slurry, and has good drying properties.

[Prior Technical Literature]

【Patent Literature】

[Patent Document 1] Japanese Patent Publication No. 2003-187638

[Patent Document 2] Japanese Patent Publication No. 2003-242835

[Patent Document 3] Japanese Patent Publication No. 2012-174797

Conductive slurries for gravure printing are required to have low viscosity. However, in low-viscosity conductive slurries, the waviness of the film surface tends to be larger when forming a dry film compared to high-viscosity conductive slurries for screen printing. When such conductive slurries are used to form the internal electrode layer of a multilayer ceramic capacitor, the film thickness of the resulting internal electrode layer varies, reducing the reliability of the multilayer ceramic capacitor.

In view of such a situation, the object of the present invention is to provide a conductive slurry for gravure printing with a smaller waviness on the surface of the dried film.

In the first aspect of the present invention, a conductive slurry for gravure printing is provided, which contains conductive powder, ceramic powder, dispersant, binder resin and organic solvent, wherein the organic solvent contains a first organic solvent, and the first organic solvent is at least one terpene solvent selected from the group consisting of terpineol, dihydroterpineol and dihydroterpineol acetate.

In addition, the conductive slurry further contains dicarboxylic acid at a level of 0.05% by mass or more and less than 3.0% by mass relative to the conductive slurry as a whole. In addition, it is ideal to contain a first organic solvent at a level of 10% by mass or more and less than 60% by mass relative to the conductive slurry as a whole. In addition, it is ideal to contain a dispersant at a level of 0.01% by mass or more and less than 3.0% by mass relative to the conductive slurry as a whole. In addition, the dispersant is ideal to contain an acidic dispersant.

In addition, the organic solvent further contains a second organic solvent, and the second organic solvent can be at least one selected from the group consisting of isobornyl acetate, methyl isobutyl ketone, and diisobutyl ketone. In addition, the organic solvent further contains a third organic solvent, and the third organic solvent can be a petroleum-based hydrocarbon solvent.

In addition, the organic solvent further contains a third organic solvent and a fourth organic solvent, the third organic solvent is a petroleum hydrocarbon solvent, and the fourth organic solvent can be at least one selected from the group consisting of the following solvents: a solvent having the same HSP distance between the HSP value of the mixed solution and the HSP value of the third organic solvent calculated based on the HSP value of each of the first organic solvent and the fourth organic solvent and the volume ratio, and a solvent having a HSP distance greater than the HSP distance between the HSP value of the first organic solvent and the HSP value of the third organic solvent. In addition, the fourth organic solvent is preferably at least one selected from the group consisting of acetate solvents, ketone solvents, and alicyclic hydrocarbon solvents. In addition, the fourth organic solvent is preferably at least one selected from the group consisting of isobornyl acetate, methyl isobutyl ketone, and diisobutyl ketone.

In addition, the conductive powder preferably contains at least one metal powder selected from the group consisting of Ni, Pd, Pt, Au, Ag, Cu and alloys thereof. In addition, the average particle size of the conductive powder is preferably not less than 0.05μm and not more than 1.0μm. In addition, the ceramic powder preferably contains barium titanate. The average particle size of the ceramic powder is preferably not less than 0.01μm and not more than 0.5μm. In addition, it is ideal to contain ceramic powder in an amount of not less than 1 mass % and not more than 20 mass % relative to the conductive slurry as a whole. In addition, the binder resin preferably contains a cellulose-based resin. In addition, ideally, the viscosity of the conductive slurry at a shear rate of 100sec ^-1 is not more than 3Pa.S, and the viscosity at a shear rate of 10000sec ^-1 is not more than 1Pa.S. In addition, the average height (Wc) of the waviness curve elements of the dried film obtained by gravure printing the conductive slurry is preferably 0.5 μm or less.

In the second aspect of the present invention, an electronic component formed using the above-mentioned conductive slurry for gravure printing is provided.

In the third aspect of the present invention, a multilayer ceramic capacitor is provided, which has at least a multilayer body formed by laminating a dielectric layer and an internal electrode layer, and the internal electrode layer is formed using the above-mentioned conductive slurry for gravure printing.

The conductive slurry of the present invention can reduce the waviness of the surface of the dry film even when the dry film is formed by gravure printing. In addition, the internal electrode layer formed by the conductive slurry of the present invention can produce a highly reliable multilayer ceramic capacitor with high productivity even when a thin-film electrode is formed.

1: Multilayer ceramic capacitors

10: Ceramic laminate

11: Internal electrode layer

12: Dielectric layer

20: External electrode

21: External electrode layer

22: Electroplating

[Figure 1] Figure 1A and Figure 1B are an oblique view and a cross-sectional view showing a multilayer ceramic capacitor according to an embodiment.

[Figure 2] is a graph showing the relationship between the HSP distance of the organic solvent used in the embodiment and the comparative example and the average height (Wc) of the waviness curve element of the dried film.

[Conductive slurry]

The conductive slurry of this embodiment contains conductive powder, ceramic powder, dispersant, binder resin and organic solvent. The following is a detailed description of each component.

(Conductive powder)

As the conductive powder, there is no particular limitation, and metal powder can be used, for example, powders of one or more selected from Ni, Pd, Pt, Au, Ag, Cu and alloys thereof can be used. Among them, from the viewpoints of conductivity, corrosion resistance and cost, powder of Ni or its alloy (hereinafter, sometimes referred to as "Ni powder") is ideal. As Ni alloy, for example, alloys of Ni and at least one element selected from the group consisting of Mn, Cr, Co, Al, Fe, Cu, Zn, Ag, Au, Pt and Pd can be used. The content of Ni in the Ni alloy is, for example, 50% by mass or more, and ideally 80% by mass or more. In addition, in order to suppress the violent gas generation caused by the partial thermal decomposition of the binder resin during the debonding treatment, the Ni powder can contain element S of several hundred ppm.

The average particle size of the conductive powder is preferably 0.05 μm to 1.0 μm, and more preferably 0.1 μm to 0.5 μm. When the average particle size of the conductive powder is within the above range, it can be suitably used as a slurry for the internal electrode of a thin-film multilayer ceramic capacitor (multilayer ceramic part), for example, to improve the smoothness and density of the dry film. The average particle size is a value obtained by observation based on a scanning electron microscope (SEM), and is an average value (SEM average particle size) obtained by measuring the particle sizes of multiple particles one by one from an image obtained by observation at a magnification of 10,000 times by SEM.

The content of the conductive powder is preferably 30% by mass or more and less than 70% by mass relative to the entire conductive slurry, and more preferably 40% by mass or more and less than 60% by mass. When the content of the conductive powder is within the above range, the conductivity and dispersibility are excellent.

(Ceramic powder)

The ceramic powder is not particularly limited, and for example, when the slurry is used for the internal electrode of a multilayer ceramic capacitor, a known ceramic powder is appropriately selected according to the type of multilayer ceramic capacitor to be used. For example, a calcite-titanate-type oxide containing Ba and Ti can be used as the ceramic powder, preferably containing barium titanate (BaTiO ₃ ).

As the ceramic powder, a ceramic powder containing barium titanate as a main component and oxides as a subcomponent may be used. Examples of the oxides include oxides of Mn, Cr, Si, Ca, Ba, Mg, V, W, Ta, Nb, and one or more rare earth elements. In addition, as the ceramic powder, for example, a calcite-titanic oxide ferroelectric ceramic powder in which Ba atoms and Ti atoms of barium titanate (BaTiO ₃ ) are replaced with other atoms such as Sn, Pb, and Zr may be used.

When used as a conductive slurry for an internal electrode, the ceramic powder may have the same composition as the dielectric ceramic powder constituting the green sheet of the multilayer ceramic capacitor (electronic component). This can suppress the generation of cracks due to shrinkage mismatch at the interface between the dielectric layer and the internal electrode layer in the sintering step. Examples of such ceramic powders include oxides such as ZnO, ferrite, PZT, BaO, _{Al2O3 , Bi2O3} , _R (rare earth element) _2O3 , _TiO2 , and _Nd2O3 in addition to the above. The ceramic powder may be _one kind or two or _more kinds.

The average particle size of the ceramic powder is, for example, 0.01 μm to 0.5 μm, and ideally 0.01 μm to 0.3 μm. When the average particle size of the ceramic powder is within the above range, a sufficiently thin and uniform internal electrode can be formed when used as an internal electrode slurry. The average particle size is a value obtained by observation based on a scanning electron microscope (SEM), and is an average value (SEM average particle size) obtained by measuring the particle sizes of multiple particles one by one from an image obtained by observation at a magnification of 50,000 times by SEM.

The content of ceramic powder relative to the total conductive slurry is ideally 1% to 20% by mass, and more ideally 3% to 15% by mass. When the content of ceramic powder is within the above range, the dispersibility and sintering properties are excellent.

In addition, based on 100 parts by mass of the conductive powder, the content of the ceramic powder is preferably 1 part by mass or more and 30 parts by mass or less, and more preferably 3 parts by mass or more and 30 parts by mass or less.

(Adhesive resin)

The binder resin is not particularly limited, and known resins can be used. Examples of the binder resin include cellulose resins such as methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, and nitrocellulose, acrylic resins, and butyral resins such as polyvinyl butyral. Among them, from the viewpoints of solubility in solvents and combustion decomposition, it is ideal to contain a cellulose resin, and it is more ideal to contain ethyl cellulose. In addition, when used as an internal electrode slurry, from the viewpoint of improving the bonding strength with the raw sheet, a butyral resin can be contained, or a butyral resin can be used alone. When the binder resin contains a butyral resin as an acetal resin, the viscosity can be easily adjusted to be suitable for gravure printing, and the bonding strength with the raw sheet can be further improved. The binder resin can contain, for example, 20% by mass or more of the acetal resin relative to the entire binder resin, or 30% by mass or more.

The degree of polymerization and weight average molecular weight of the binder resin can be appropriately adjusted within the above range according to the required viscosity of the conductive slurry.

The content of the binder resin is preferably 0.5% by mass to 10% by mass relative to the entire conductive slurry, and more preferably 1% by mass to 7% by mass. When the content of the binder resin is within the above range, the conductivity and dispersibility are excellent.

Based on 100 parts by mass of the conductive powder, the content of the binder resin is preferably 1 part by mass to 20 parts by mass, and more preferably 1 part by mass to 14 parts by mass.

(Organic solvent)

The conductive slurry involved in this embodiment contains an organic solvent. Among the organic solvents, at least one terpene solvent selected from the group consisting of terpineol, dihydroterpineol and dihydroterpineol acetate is contained as the first organic solvent, and dihydroterpineol is preferably contained. By containing the above-mentioned terpene solvent, the conductive slurry can reduce the waviness of the film surface when forming a dry film. In addition, the above-mentioned terpene solvent can be used alone or in combination of two or more.

Relative to the total amount of the conductive slurry, the content of the terpene solvent (first organic solvent) can be 10% by mass to 60% by mass, preferably 10% by mass to 45% by mass, more preferably 10% by mass to 40% by mass, and further preferably 15% by mass to 40% by mass. When the content of the first organic solvent is within the above range, the conductivity and dispersibility are excellent.

In addition, when two or more kinds of organic solvents are contained as the first organic solvent, dihydroterpineol and dihydroterpineol acetate are preferably contained. In the case of containing dihydroterpineol and dihydroterpineol acetate, the waviness of the film surface when forming a dry film can be further reduced, and the generation of floating white can be suppressed. In addition, in this case, relative to the total amount of the conductive slurry, the content of dihydroterpineol is preferably 10% by mass to 60% by mass, more preferably 10% by mass to 45% by mass, and further more preferably 15% by mass to 40% by mass. In addition, relative to the total amount of the conductive slurry, the content of dihydroterpineol acetate is preferably 3% by mass to 20% by mass. In addition, the content of dihydroterpineol may be greater than the content of dihydroterpineol acetate.

In addition, as an organic solvent, an organic solvent other than the first organic solvent may be contained. As an organic solvent other than the first organic solvent (other organic solvent), there is no particular limitation, and a known organic solvent capable of dissolving the above-mentioned adhesive resin can be used. As an organic solvent other than the above-mentioned terpene solvent (first organic solvent), for example, glycol ether solvents, acetate solvents, ketone solvents, terpene solvents other than the above-mentioned first organic solvent, aliphatic hydrocarbon solvents, etc. can be listed. In addition, one organic solvent may be used, or two or more organic solvents may be used. The organic solvent may contain, for example, the above-mentioned terpene solvent (first organic solvent) as a main solvent, and an organic solvent other than the above-mentioned terpene solvent as a secondary solvent. In this case, the above-mentioned terpene solvent may contain, for example, 30 to 50 parts by mass based on 100 parts by mass of the conductive powder. In addition, the secondary solvent may contain 20 to 40 parts by mass based on 100 parts by mass of the conductive powder.

The organic solvent may contain, for example, the first organic solvent and an organic solvent other than the first organic solvent. In this case, relative to 100 parts by mass of the conductive powder, the first organic solvent is, for example, 10 parts by mass to 120 parts by mass, preferably 15 parts by mass to 90 parts by mass, and more preferably 20 parts by mass to 50 parts by mass. In addition, relative to 100 parts by mass of the conductive powder, the organic solvent other than the first organic solvent is, for example, 5 parts by mass to 100 parts by mass, preferably 15 parts by mass to 90 parts by mass, and more preferably 30 parts by mass to 70 parts by mass.

As organic solvents other than the first organic solvent, for example, acetate-based solvents and aliphatic hydrocarbon solvents may be included. As acetate-based solvents, for example, glycol ether acetates such as isobornyl acetate (IBA), isobornyl propionate, isobornyl butyrate, isobornyl isobutyrate, ethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, 3-methoxy-3-methylbutyl acetate, 1-methoxypropyl-2-acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, etc., may be listed. As ketone-based solvents, methyl ethyl ketone, methyl isobutyl ketone (MIBK), etc. may be listed. As aliphatic hydrocarbon solvents (petroleum-based hydrocarbons), tridecane, nonane, cyclohexane, etc. may be listed. In addition, it is ideal to contain mineral essence (MA).

Relative to the total amount of the conductive slurry, the content of the organic solvent (as a whole) is preferably 20% by mass or more and 60% by mass or less, and more preferably 25% by mass or more and 45% by mass or less. When the content of the organic solvent is within the above range, the conductivity and dispersibility are excellent.

The lower limit of the content of the organic solvent is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and further preferably 35 parts by mass or more relative to 100 parts by mass of the conductive powder. In addition, the upper limit of the content of the organic solvent is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 80 parts by mass or less relative to 100 parts by mass of the conductive powder. In addition, based on 100 parts by mass of the conductive powder, the content of the organic solvent can be, for example, 50 parts by mass or more and 130 parts by mass or less, or 60 parts by mass or more and 90 parts by mass or less. When the content of the organic solvent is within the above range, the conductivity and dispersibility are excellent.

Hereinafter, an example of an ideal state of the combination of the first organic solvent and an organic solvent other than the first organic solvent will be described. In addition, the combination of the first organic solvent and an organic solvent other than the first organic solvent is not limited to the following example.

(a) A first organic solvent and a second organic solvent

The organic solvent may contain a first organic solvent and a second organic solvent. The second organic solvent is at least one selected from the group consisting of isobornyl acetate (IBA), methyl isobutyl ketone (MIBK) and diisobutyl ketone (DIBK), preferably one or both of isobornyl acetate (IBA) and methyl isobutyl ketone, and more preferably isobornyl acetate. When the conductive slurry contains the first organic solvent and the second organic solvent, the waviness of the surface of the dried film can be further reduced, and the generation of whitening can be suppressed.

In addition, the content of the second organic solvent is preferably 3% by mass to 20% by mass, and more preferably 4% by mass to 15% by mass, relative to the total amount of the conductive slurry. In addition, the second organic solvent can be 5% or more, or 6% or more relative to the total amount of the conductive slurry. When the content of the second organic solvent is within the above range and is relatively high, the waviness of the surface of the dry film can be further reduced.

(b) A first organic solvent and a third organic solvent

The organic solvent may contain a first organic solvent and a third organic solvent. The third organic solvent is an aliphatic hydrocarbon solvent (petroleum hydrocarbon solvent), and may contain tridecane, nonane, cyclohexane, etc., and is preferably mineral spirits (MA). By containing the third organic solvent, the viscosity of the conductive slurry can be easily adjusted to a viscosity suitable for gravure printing.

As the content ratio of the first organic solvent to the third organic solvent, for example, with the organic solvent as 100 mass%, the first organic solvent: the second organic solvent: the third organic solvent = 5.0~80: 0~60: 0~50 (mass ratio), or 20~50: 20~50: 0~30 (mass ratio). When the ratio of each organic solvent is within the above range, the smoothness of the dried film surface is further improved.

(c) A first organic solvent, a third organic solvent, and a fourth organic solvent

In addition, when the organic solvent contains the first organic solvent and the third organic solvent, it may further contain a fourth organic solvent. The fourth organic solvent is at least one selected from the group consisting of the following solvents: a solvent having the same HSP distance between the HSP value of the mixed solution and the HSP value of the third organic solvent calculated based on the HSP value of each of the first organic solvent and the fourth organic solvent and the HSP value of the third organic solvent, and a solvent having a shorter HSP distance than the HSP distance between the HSP value of the first organic solvent and the HSP value of the third organic solvent. When the conductive slurry contains a fourth organic solvent in addition to the first organic solvent and the third organic solvent, the waviness of the surface of the dried film can be further reduced, and the occurrence of white floating on the upper portion of the white separation layer containing ceramic powder when the conductive slurry is prepared can be suppressed.

In addition, the HSP distance between the HSP value of the mixed solution calculated based on the HSP value of each of the first organic solvent and the fourth organic solvent and the HSP value of the third organic solvent is, for example, ideally 6.2 or less, more ideally 6.0 or less, further ideally 5.6 or less, and particularly ideally 5.0 or less. When the HSP distance is within the above range, the waviness of the surface of the dried film can be further reduced. In addition, the HSP distance between the HSP value of the mixed solution of the first organic solvent and the fourth organic solvent and the HSP value of the third organic solvent can be the same as the HSP distance between the HSP value of the first organic solvent and the HSP value of the third organic solvent, but is ideally shorter.

In addition, HSP distance refers to the distance between the Hansen solubility parameters (HSP values) of each organic solvent. Hansen solubility parameter is one of the indicators that represent the solubility of a substance, and represents the solubility as a three-dimensional vector. This three-dimensional vector can be represented by dispersion force (δd), polarity (δp), and hydrogen bond (δh). The closer the distance of Hansen solubility parameters (HSP distance), the higher the compatibility can be evaluated.

The HSP distance in this manual can be calculated using the HSP value of the organic solvent registered in the database of the Hansen Solubility Parameter software HSPiP (Hansen Solubility Parameter in Practice). In addition, in the present invention, for organic solvents registered in the HSPiP version 5 database, this value is used, and for solvents not registered in the database, the value estimated by HSPiP version 5 is used. In addition, in the case of a mixed solvent formed by mixing multiple organic solvents, the HSP value is calculated by accumulating the mixed volume ratio on the individual HSP values (components of the three-dimensional vector) of the mixed organic solvents and adding them.

In addition, the fourth organic solvent is not particularly limited as long as it satisfies the above-mentioned characteristics. The fourth organic solvent is, for example, preferably at least one selected from the group consisting of acetate-based solvents, ketone-based solvents, and alicyclic hydrocarbon-based solvents, and more preferably at least one selected from the group consisting of isobornyl acetate, methyl isobutyl ketone, diisobutyl ketone, and dihydroterpineol acetate. In addition, as the fourth organic solvent, any solvent that satisfies the above-mentioned HSP distance can be selected from the above-mentioned second organic solvent.

When the conductive slurry contains the first organic solvent, the third organic solvent and the fourth organic solvent, the content of the third organic solvent is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and further preferably 5% by mass to 10% by mass, relative to the total amount of the conductive slurry. In addition, the content of the fourth organic solvent is preferably 3% by mass to 35% by mass, more preferably 4% by mass to 25% by mass, and further preferably 6% by mass to 20% by mass, relative to the total amount of the conductive slurry.

(Dispersant)

The conductive slurry involved in this embodiment contains a dispersant as an additive. As the dispersant, a known dispersant can be used. As the dispersant, for example, an acidic dispersant can be contained. In addition, as the acidic dispersant, an acidic dispersant having a carboxyl group other than the dicarboxylic acid described later can also be contained. In addition, in this specification, as described later, focusing on the separation inhibition effect of the dicarboxylic acid on the conductive powder and the ceramic powder, the dicarboxylic acid and the dispersant are separately specified.

For example, when comb-type carboxylic acid is used as a dispersant, the dispersibility of the conductive slurry is improved by containing the comb-type carboxylic acid. In addition, the dispersant may be one or more. The conductive slurry involved in this embodiment has improved dispersibility by containing a dispersant.

As a dispersant, for example, an acidic dispersant having a hydroxyl group may be contained. Examples of such an acidic dispersant include acidic dispersants such as higher fatty acids, polymer surfactants, and phosphoric acid dispersants. Such dispersants may be used alone or in combination of two or more.

As a higher fatty acid, it can be an unsaturated carboxylic acid or a saturated carboxylic acid, and there is no particular limitation. Examples include stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, linolenic acid, and other higher fatty acids with 11 or more carbon atoms. Among them, oleic acid or stearic acid is preferred.

There are no particular limitations on other acid-based dispersants, and examples thereof include alkyl monoamine salt-type dispersants represented by monoalkylamine salts.

As the alkyl monoamine salt type, for example, oleyl sarcosine, which is a compound of glycine and oleic acid, or an amide compound obtained by using a higher fatty acid such as stearic acid or lauric acid instead of oleic acid is preferred.

In addition, the dispersant may contain dispersants other than acidic dispersants. Examples of dispersants other than acidic dispersants include alkaline dispersants, nonionic dispersants, and amphoteric dispersants. These dispersants may be used alone or in combination of two or more.

Examples of alkaline dispersants include fatty amines such as lauryl amine, rosin amine, cetyl amine, myristic amine, and stearyl amine. When the above acidic dispersants and alkaline dispersants are contained, the dispersibility of the conductive slurry is better and the viscosity stability over time is also excellent.

It is ideal to contain 3% or less of dispersant relative to the entire conductive slurry. The upper limit of the dispersant content is ideally 2% or less, and more ideally 1% or less. The lower limit of the dispersant content is not particularly limited, for example, it is 0.01% or more, and ideally 0.05% or more. When the dispersant content is within the above range, the viscosity of the slurry can be adjusted to an appropriate range while improving the dispersibility of the conductive slurry. In addition, it can prevent the deterioration of the drying property after printing, and further suppress sheet erosion and poor peeling of the raw sheet.

In addition, relative to 100 parts by mass of the conductive powder, the dispersant is preferably contained in an amount of 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, and further preferably 0.4 to 3 parts by mass. When the content of the dispersant is within the above range, the dispersibility of the conductive powder and ceramic powder, and the smoothness of the dry electrode surface after coating are better, and the viscosity of the conductive slurry can be adjusted to an appropriate range. In addition, the deterioration of the drying property after printing can be prevented, and the sheet erosion and the poor peeling of the green sheet can be further suppressed.

(Dicarboxylic acid)

The conductive slurry involved in this embodiment can contain dicarboxylic acid as an additive. In the conductive slurry for gravure printing, by containing a specific amount of dicarboxylic acid, the separation inhibition effect of the conductive powder and the ceramic powder can be improved, thereby inhibiting the generation of whitening when manufacturing the conductive slurry. In addition, the coverage rate when forming the internal electrode layer using the conductive slurry involved in this embodiment can be improved.

Dicarboxylic acids are carboxylic acid-based additives with two carboxyl groups (COO- groups). Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalene dicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, and azelaic acid; dibasic acids generated by dimerization of unsaturated fatty acids with 12 to 28 carbon atoms such as dimer acid, and hydrogenated dicarboxylic acids. Polyacid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 2-methylhexahydrophthalic anhydride, dicarboxy hydrogenated bisphenol A, dicarboxy hydrogenated bisphenol S, hydrogenated naphthalene dicarboxylic acid, tricyclodecane dicarboxylic acid and other alicyclic dicarboxylic acids, etc.

In addition, the average molecular weight of the dicarboxylic acid is not particularly limited, and may be, for example, 1000 or less, 500 or less, or 400 or less. When the average molecular weight of the dicarboxylic acid is within the above range, a higher separation inhibition effect can be obtained.

In addition, the conductive slurry involved in this embodiment contains dicarboxylic acid at a content of 0.05 mass% or more and less than 3.0 mass% relative to the entire conductive slurry, preferably 0.1 mass% or more and less than 3.0 mass%, and more preferably 0.1 mass% or more and 1.0 mass% or less. When the content of dicarboxylic acid is too high, the internal electrode layer becomes soft due to insufficient drying during the printing and drying steps, and sometimes the layering is misaligned in the subsequent layering step, or the residual dicarboxylic acid is vaporized during firing, and internal stress is generated due to the vaporized gas component, or the structure of the layered body is destroyed.

In addition, when the conductive slurry contains a dispersant (excluding dicarboxylic acid) and a dicarboxylic acid, the total content of the dispersant and the dicarboxylic acid may be 0.05% by mass to 3.0% by mass, 0.1% by mass to 2.0% by mass, or 0.1% by mass to 1.0% by mass, relative to the entire conductive slurry.

(Other additives)

The conductive slurry of this embodiment may contain other additives other than the above-mentioned components as needed. As other additives, for example, conventionally known additives such as defoamers, plasticizers, surfactants, and thickeners may be used.

(Conductive slurry)

The method for producing the conductive slurry involved in this embodiment is not particularly limited, and a conventionally known method can be used. For example, the conductive slurry can be produced by stirring and kneading the above-mentioned components with a three-roll mill, a ball mill, a mixer, etc. In addition, for dicarboxylic acid, it is ideal to weigh and add it together with other materials when stirring and kneading with a mixer, etc., but adding it after stirring and kneading (dispersing) other materials can also obtain the effect of inhibiting the separation of conductive powder and ceramic powder.

The viscosity of the conductive slurry at a shear rate of 100 sec ^-1 is preferably 3 Pa. S or less. When the viscosity at a shear rate of 100 sec ^-1 is within the above range, it can be suitably used as a conductive slurry for gravure printing. If it exceeds the above range, the viscosity is too high and there is a possibility that it is not suitable for gravure printing. The lower limit of the viscosity at a shear rate of 100 sec ^-1 is not particularly limited, and is, for example, 0.2 Pa. S or more.

In addition, the viscosity of the conductive slurry at a shear rate of 10000 sec ^-1 is preferably 1 Pa. S or less. When the viscosity at a shear rate of 10000 sec ^- 1 is within the above range, it can be used appropriately as a conductive slurry for gravure printing. When it exceeds the above range, the viscosity may be too high and unsuitable for gravure printing. The lower limit of the viscosity at a shear rate of 10000 sec ^-1 is not particularly limited, and is, for example, 0.05 Pa. S or more.

Conductive slurry can be suitably used in electronic parts such as multilayer ceramic capacitors. Multilayer ceramic capacitors have a dielectric layer formed using a dielectric green sheet and an internal electrode layer formed using a conductive slurry. The internal electrode layer can be obtained by drying a film printed with a conductive slurry to obtain a dry film, and then firing the dry film.

As a dry film obtained by gravure printing a conductive slurry at a printing speed of 35m/min and a film thickness of 0.50μm to 2μm, the average height (Wc) of the corrugation curve element when the cutoff value (λc=0.25mm) is applied is preferably 0.5μm or less, more preferably 0.4μm or less, and can also be 0.35μm or less. When the average height (Wc) of the corrugation curve element of the dry film is within the above range, a multilayer ceramic capacitor with high reliability can be obtained with high productivity.

In addition, as a dry film obtained by gravure printing a conductive slurry at a printing speed of 30m/min and a film thickness of 0.50μm to 2μm, the average height (Wc) of the waviness curve element when the cutoff value (λc=0.08mm) is applied is preferably 0.50μm or less, more preferably 0.4μm or less, and further preferably 0.35μm or less.

In addition, the average height (Wc) of the corrugation curve element can be measured in accordance with JISB0601:2013. The average height (Wc) of the corrugation curve element refers to the average value of the height (Zti) of the corrugation curve element (contour curve element) in the reference length. The contour curve element is an element that groups adjacent peaks and valleys, and the height of the contour curve element is equal to the height difference between the adjacent peaks and valleys. In addition, the peaks (valleys) that constitute the contour element have the minimum height and minimum length regulations, and the height (depth) is less than 10% of the maximum height, or the length is less than 1% of the length of the calculation interval. It is regarded as noise as part of the continuous valley (peak) before and after.

[Electronic parts]

Hereinafter, the implementation forms of the electronic components of the present invention are described with reference to the drawings. In the drawings, the components are sometimes appropriately represented in a schematic manner or with a changed scale. In addition, the positions and directions of the components are described with reference to the XYZ orthogonal coordinate system shown in FIG. 1A and FIG. 1B. In the XYZ orthogonal coordinate system, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction (up and down direction).

FIG. 1A and FIG. 1B are diagrams showing a multilayer ceramic capacitor 1 as an example of an electronic component involved in the embodiment. The multilayer ceramic capacitor 1 includes a ceramic multilayer body 10 in which dielectric layers 12 and internal electrode layers 11 are alternately stacked, and an external electrode 20.

The following is a description of a method for manufacturing a multilayer ceramic capacitor using the above-mentioned conductive slurry. First, a conductive slurry is printed on a ceramic green sheet and dried to form a dry film. After a plurality of ceramic green sheets having the dry film on the upper surface are laminated by compression bonding to obtain a laminated body, the laminated body is fired to be integrated, thereby preparing a ceramic laminated body 10 in which internal electrode layers 11 and dielectric layers 12 are alternately laminated. Thereafter, a pair of external electrodes are formed at both ends of the ceramic laminated body 10 to manufacture a multilayer ceramic capacitor 1. A more detailed description is given below.

First, a ceramic green sheet as an unfired ceramic sheet is prepared. As the ceramic green sheet, for example, a dielectric layer slurry obtained by adding an organic binder such as polyvinyl butyral and a solvent such as terpineol to a specified ceramic raw material powder such as barium titanium oxide is coated on a support film such as a PET film in a sheet shape and dried to remove the solvent. In addition, there is no particular limitation on the thickness of the dielectric layer composed of the ceramic green sheet, but from the perspective of the miniaturization of the multilayer ceramic capacitor, it is ideally 0.05μm or more and 3μm or less.

Next, a plurality of sheets are prepared in which a dry film is formed on one surface of the ceramic green sheet by printing and applying the above-mentioned conductive slurry on one surface of the ceramic green sheet using a gravure printing method and drying. In addition, from the perspective of the requirement for thinning the internal electrode layer 11, the thickness of the dry film formed by the conductive slurry is preferably less than 1μm after drying.

Next, the ceramic green sheets are peeled off from the supporting film, and after the ceramic green sheets and the dry films formed on one surface of the ceramic green sheets are alternately stacked, a laminate is obtained by heating and pressurizing. In addition, a configuration can be provided in which protective ceramic green sheets not coated with conductive slurry are further arranged on both surfaces of the laminate.

Next, after the laminate is cut into pieces of a specified size to form a green wafer, the green wafer is subjected to a debinder treatment and fired in a reducing environment, thereby manufacturing a laminated ceramic fired body (ceramic laminate 10). In addition, the environment during the debinder treatment is preferably an atmospheric air or _N2 gas environment. The temperature during the debinder treatment is, for example, 200°C to 400°C. In addition, the holding time of the above temperature during the debinder treatment is preferably 0.5 hours to 24 hours. In order to suppress oxidation of the metal used in the internal electrode layer, the sintering is performed in a reducing environment. The temperature during sintering of the laminate is, for example, 1000° C. to 1350° C., and the temperature is maintained for, for example, 0.5 hour to 8 hours.

By firing the green sheet, the organic binder in the ceramic green sheet is completely removed, and the ceramic raw material powder is fired to form a ceramic dielectric layer 12. In addition, the organic carrier in the dried film is removed, and the nickel powder or the alloy powder with nickel as the main component is sintered or melted to form an internal electrode layer 11, and then a laminated ceramic fired body is formed in which the dielectric layer 12 and the internal electrode layer 11 are alternately stacked in multiple layers. In addition, from the perspective of bringing oxygen into the interior of the dielectric layer to improve reliability and suppressing reoxidation of the internal electrode, the laminated ceramic fired body after firing can be annealed.

Then, the multilayer ceramic capacitor 1 is manufactured by providing a pair of external electrodes 20 to the prepared multilayer ceramic sintered body. For example, the external electrode 20 has an external electrode layer 21 and a plating layer 22. The external electrode layer 21 is electrically connected to the internal electrode layer 11. In addition, as a material of the external electrode 20, for example, copper, nickel, or an alloy thereof can be preferably used. In addition, electronic components other than multilayer ceramic capacitors can also be used.

[Implementation Example]

The present invention is described in detail below based on embodiments and comparative examples, but the present invention is not limited to the embodiments in any way.

[Evaluation method]

(Viscosity of conductive slurry)

The viscosity of the conductive slurry after production was measured using a rheometer (Anton Paar Japan Co., Ltd.: Rheometer MCR302). The viscosity was measured using a cone plate with a cone angle of 1° and a diameter of 25 mm at a shear rate (shear speed) of 100 sec ^-1 and 10,000 sec ^-1 .

(Evaluation of waviness of dried film)

(1) Example 1A and Comparative Example 1A were evaluated for waviness using the following method

The conductive slurry was printed on a dielectric sheet using a small gravure printer (manufactured by Kurafuki Textile Co., Ltd., GP-10TYPEII) at a printing speed of 35 m/min and a conductive powder (Ni powder) of 0.7 mg/ ^cm2. The film was then dried in a box dryer at 80°C for 4 minutes and taken out to obtain a dry film (2.5 mm wide × 5 mm long) for evaluation. The film thickness of the dry film was 0.50 μm or more and 2 μm or less.

The waviness of the dried film surface was evaluated using a laser microscope (VK-100 manufactured by KEYENCE, measuring lens ×20, measuring length: 2000μm) with the average height (Wc) of the waviness curve element when a cutoff value (λc=0.25mm) was applied. The average height (Wc) of the waviness curve element was the average value of multiple evaluations.

(2) The waviness of the other embodiments and comparative examples other than Embodiment 1A and Comparative Example 1A was evaluated by the following method.

The conductive slurry was printed on a dielectric sheet using a small gravure printer (manufactured by Kurafuki Textile Co., Ltd., GP-10TYPEII) at a printing speed of 30 m/min and a conductive powder (Ni powder) of 0.7 mg/ ^cm2. The film was then dried in a box dryer at 80°C for 4 minutes and taken out to obtain a dry film (2.5 mm wide × 5 mm long) for evaluation. The film thickness of the dry film was 0.50 μm or more and 2 μm or less.

The waviness of the dried film surface was evaluated using a laser microscope (VK-100 manufactured by KEYENCE, measuring lens ×20, measuring length: 2000μm) with the average height (Wc) of the waviness curve element when a cutoff value (λc=0.08mm) was applied. The average height (Wc) of the waviness curve element was the average value of multiple evaluations.

[Materials used]

(Conductive powder)

As the conductive powder, Ni powder (SEM average particle size: 0.2μm) was used.

(Ceramic powder)

Barium titanium oxide (BaTiO ₃ ; SEM average particle size: 0.10 μm) was used as the ceramic powder.

(Adhesive resin)

As the adhesive resin, polyvinyl butyral resin and ethyl cellulose are used.

(Additives)

As an additive, dicarboxylic acid is used.

(Dispersant)

As dispersants, acidic dispersants and alkaline dispersants are used. In addition, as an acidic dispersant, a mixed acidic dispersant composed of a comb-type carboxylic acid and a phosphoric acid dispersant is used, and as an alkaline dispersant, oleylamine is used.

(Organic solvent)

As organic solvents, dihydroterpineol (DHT), propylene glycol monobutyl ether (PNB), mineral spirits (MA), isobornyl acetate (IBA), methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), propylene glycol monomethyl ether acetate (PMA), dipropylene glycol monomethyl ether acetate (DPMA), and diethylene glycol monomethyl ether (DEGME) were used.

[Example 1A]

Conductive slurry was prepared by adding 50 mass% of conductive powder, 12.5 mass% of ceramic powder, 0.7 mass% of dispersant (0.4 mass% of acidic dispersant, 0.3 mass% of alkaline dispersant), 0.3 mass% of dicarboxylic acid, 2.5 mass% of binder resin (polyvinyl butyral resin: ethyl cellulose = 1:2 (mass ratio)) and the balance of organic solvent (MA 13.6 mass%, balance DHT) in a total of 100 mass% and mixing these materials. The content of additives and the evaluation results of the average height of the waviness Wc of the conductive slurry are shown in Table 1.

[Comparative Example 1A]

Conductive slurry was prepared and evaluated in the same manner as Example 1A except that PNB was used instead of DHT. The evaluation results Wc of the content of additives, etc. in the conductive slurry and the average height of the waviness are shown in Table 1.

【Table 1】

(Evaluation result 1)

The conductive slurry of Example 1A has a smaller average height (Wc) of the waviness curve element in the dried film (cutoff value: λc=0.25mm) than the conductive slurry of Comparative Example 1A which does not use a terpene-based organic solvent.

In addition, in all the conductive slurries of the examples and comparative examples shown in Table 1, it was confirmed that the viscosity was 3 Pa. S or less at a shear rate of 100 sec ^-1 and the viscosity was 1 Pa. S or less at a shear rate of 10000 sec ^-1 , which had a viscosity suitable for gravure printing.

[Example 1B]

Conductive slurry was prepared by adding 50 mass% of conductive powder, 12.5 mass% of ceramic powder, 0.5 mass% of dispersant (0.3 mass% of acidic dispersant, 0.2 mass% of alkaline dispersant), 0.2 mass% of dicarboxylic acid, 2.5 mass% of binder resin (polyvinyl butyral resin: ethyl cellulose = 1:2 (mass ratio)), and the balance of organic solvent (MA 13.7 mass%, balance DHT), and mixing these materials in a total of 100 mass%. The content of additives and the evaluation results of the average height of the waviness Wc of the conductive slurry are shown in Table 2.

[Example 1C]

Conductive slurry was prepared and evaluated in the same manner as Example 1B, except that 4.1% by mass of DHTA was added as an organic solvent and 12.0% by mass of MA was added as the balance of DHT. The evaluation results Wc of the content of additives and the average height of waviness of the conductive slurry are shown in Table 2.

[Implementation Example 1D]

Conductive slurry was prepared and evaluated in the same manner as Example 1B, except that dicarboxylic acid was not added and 13.8 mass % of MA was added as an organic solvent and DHT was added as the balance. The evaluation results Wc of the content of additives and the average height of waviness of the conductive slurry are shown in Table 2.

[Comparative Example 1B]

The conductive slurry was prepared and evaluated in the same manner as Example 1B except that PNB was used instead of DHT. The evaluation results Wc of the content of additives and the average height of the waviness of the conductive slurry are shown in Table 2.

【Table 2】

(Evaluation result 2)

The conductive slurries of Example 1B, Example 1C, and Example 1D have smaller average heights (Wc) of the waviness curve elements in the dried films (cutoff value: λc=0.08mm) than the conductive slurry of Comparative Example 1B which does not use the first organic solvent (terpene-based organic solvent).

In addition, the conductive slurry of Example 1C using DHT and DHTA as the first organic solvent has a smaller average height (Wc) of the waviness curve element in the dried film (cutoff value: λc=0.08mm) than the conductive slurry of Example 1B using DHT as the first organic solvent.

In addition, the conductive slurry of Example 1D, which does not add dicarboxylic acid and uses only a combination of the first organic solvent and the third organic solvent in the organic solvent, can obtain a Wc value that is approximately the same as the conductive slurry of Example 1B, which adds dicarboxylic acid and has similar other compositions.

In addition, in all the conductive slurries of the examples and comparative examples shown in Table 2, it was confirmed that the viscosity was 3 Pa. S or less at a shear rate of 100 sec ^-1 and the viscosity was 1 Pa. S or less at a shear rate of 10000 sec ^-1 , which had a viscosity suitable for gravure printing.

[Examples 2B~7B, 5D, 8B~10B]

The samples containing the first organic solvent and the second organic solvent as the organic solvent were evaluated. That is, as shown in Table 3, in Examples 2B to 7B, MIBK 4.1 mass%, MA 12.0 mass%, and DHT as the balance were added as the organic solvent (Example 2B), DIBK 4.1 mass%, MA 12.0 mass%, and DHT as the balance (Example 3B), DIBK 5.1 mass%, MA 10.3 mass%, and DHT as the balance (Example 4B), I Conductive slurries were prepared and evaluated in the same manner as in Example 1B except that BA 4.1 mass%, MA 12.0 mass% and DHT as the balance (Example 5B), IBA 8.6 mass%, MA 10.3 mass% and DHT as the balance (Example 6B), and IBA 8.6 mass%, DIBK 12.0 mass% and DHT as the balance (Example 7B).

In addition, as shown in Table 3, in Example 5D, no dicarboxylic acid was added, and IBA 4.2 mass %, MA 12.0 mass % and DHT as the balance were added as organic solvents. In addition, the conductive slurry was prepared and evaluated in the same manner as in Example 1B. The content of the organic solvent in the prepared conductive slurry and the evaluation result Wc of the average height of the waviness are shown in Table 3.

Conductive slurry was prepared and evaluated in the same manner as in Example 2B, except that PMA (Example 8B), DPMA (Example 9B), and DEGME (Example 10B) were used instead of MIBK. The content of additives and the evaluation results Wc of the average height of the waviness in the prepared conductive slurry are shown in Table 3.

In addition, for reference, the evaluation results Wc of the organic solvent content and the average height of the waviness of the above-mentioned Example 1B and Comparative Example 1B are also shown in Table 3.

【Table 3】

(Evaluation result 3)

The conductive slurries of Examples 2B to 10B and 5D have a smaller average height (Wc) of the waviness curve elements in the dried film (cutoff value: λc=0.08mm) than the conductive slurry of Comparative Example 1B which does not use the first organic solvent (terpene-based organic solvent).

In addition, the conductive slurries of Examples 2B to 7B containing a second organic solvent (MIBK, DIBK, IBA) in addition to the first organic solvent, as an organic solvent, have a smaller average height (Wc) of the waviness curve element in the dried film (cutoff value: λc=0.08mm) compared to Examples 8B to 10B containing other organic solvents shown in Table 3 in addition to the first organic solvent.

In addition, the conductive slurry of Example 5D without adding dicarboxylic acid can obtain a Wc value that is approximately the same as the conductive slurry of Example 5B with adding dicarboxylic acid and similar other compositions.

In addition, even the conductive slurry of Example 7B, which does not add the third organic solvent but contains the first organic solvent and the second organic solvent, can obtain the same Wc value as the example containing the third organic solvent in addition to the first organic solvent and the second organic solvent. In addition, in Example 7B, in order to adjust the viscosity of the slurry, more DIBK as the second organic solvent is contained than in other examples (to the same extent as the content of the first organic solvent).

In addition, in all the conductive slurries of the examples and comparative examples shown in Table 3, it was confirmed that the viscosity was 3 Pa. S or less at a shear rate of 100 sec ^-1 and the viscosity was 1 Pa. S or less at a shear rate of 10000 sec ^-1 , which had a viscosity suitable for gravure printing.

[Relationship between HSP distance and average height (Wc) of waviness curve elements of dry film]

Table 4 below is a table showing the relationship between the HSP distance (compatibility) between the first organic solvent, the fourth organic solvent, other organic solvents, or mixed organic solvents thereof and the third organic solvent in the evaluation conductive slurry of Example 1B to Example 6B, Example 8B to Example 10B and Comparative Example 1B, and the average height (Wc) of the waviness when preparing a dry film. In addition, FIG. 2 is a graph showing the relationship between the HSP distance relative to the third organic solvent and the average height (Wc) of the waviness in the Examples and Comparative Examples shown in Table 4 below.

【Table 4】

(Evaluation result 4)

As shown in Table 4 and Figure 2, it is clear that, in addition to the first organic solvent and the third organic solvent, the fourth organic solvent further contains the following organic solvent, i.e., an organic solvent whose HSP distance of the mixed solution relative to the third organic solvent calculated based on the HSP values and volume ratio of the first organic solvent and the fourth organic solvent is the same as or shorter than the HSP distance of the first organic solvent relative to the third organic solvent. In this case, there is a tendency that the average height (Wc) of the waviness becomes smaller in accordance with the HSP distance relative to the third organic solvent.

【Industrial Utilization】

When the conductive slurry of the present invention is used to form the internal electrode of a multilayer ceramic capacitor, a multilayer ceramic capacitor with high reliability can be obtained with high productivity. Therefore, the conductive slurry of the present invention can be particularly suitably used as a raw material for the internal electrode of a multilayer ceramic capacitor for chip parts of increasingly miniaturized electronic devices such as mobile phones and digital devices, and can be suitably used as a conductive slurry for gravure printing.

In addition, the technical scope of the present invention is not limited to the aspects described in the above embodiments, etc. One or more elements described in the above embodiments, etc. may be omitted. In addition, the elements described in the above embodiments, etc. may be appropriately combined. In addition, as long as it is within the scope permitted by law, the disclosure contents of Japanese Patent Application No. 2019-215974 filed in Japan and all documents cited in the above embodiments, etc. are cited and made part of the description of this specification.

10: Ceramic laminate

11: Internal electrode layer

12: Dielectric layer

20: External electrode

21: External electrode layer

22: Electroplating

Claims (18)

A conductive slurry for gravure printing comprises conductive powder, ceramic powder, dispersant, binder resin and organic solvent, wherein the organic solvent comprises a first organic solvent and a second organic solvent, the first organic solvent is at least one terpene solvent selected from the group consisting of terpineol, dihydroterpineol and dihydroterpineol acetate, the second organic solvent is at least one selected from isobornyl acetate and diisobutyl ketone, and the viscosity of the conductive slurry for gravure printing is less than 3 Pa.S at a shear rate of 100 sec ^-1 and less than 1 Pa.S at a shear rate of 10000 sec ^-1 . The conductive slurry for gravure printing as described in claim 1 further contains a dicarboxylic acid in an amount of 0.05% by mass or more and less than 3.0% by mass relative to the entire conductive slurry. The conductive slurry for gravure printing as described in claim 1 or 2 contains the first organic solvent in an amount of 10% by mass to 60% by mass relative to the entire conductive slurry. The conductive slurry for gravure printing as described in claim 1 or 2 contains the dispersant in an amount of 0.01 mass % to 3.0 mass % relative to the entire conductive slurry. The conductive slurry for gravure printing as described in claim 1 or 2, wherein the dispersant contains an acid-based dispersant. The conductive slurry for gravure printing as described in claim 1 or 2, wherein the organic solvent further contains a third organic solvent, and the third organic solvent is a petroleum-based hydrocarbon solvent. A conductive slurry for gravure printing, comprising conductive powder, ceramic powder, dispersant, binder resin and organic solvent, characterized in that the organic solvent comprises a first organic solvent, a third organic solvent and a fourth organic solvent, the first organic solvent is at least one terpene solvent selected from the group consisting of terpineol, dihydroterpineol and dihydroterpineol acetate, the third organic solvent is a petroleum hydrocarbon solvent, the fourth organic solvent is an acetate solvent The fourth organic solvent is at least one selected from the group consisting of an organic solvent, a ketone solvent and an alicyclic hydrocarbon solvent, and the fourth organic solvent is at least one selected from the group consisting of the following solvents: a solvent whose HSP distance between the HSP value of the mixed solution calculated based on the HSP value and the volume ratio of the first organic solvent and the fourth organic solvent and the HSP value of the third organic solvent is shorter than the HSP distance between the HSP value of the first organic solvent and the HSP value of the third organic solvent. The conductive slurry for gravure printing as described in claim 7, wherein the fourth organic solvent is at least one selected from the group consisting of isobornyl acetate, methyl isobutyl ketone, and diisobutyl ketone. The conductive slurry for gravure printing as described in claim 1 or 7, wherein the conductive powder contains at least one metal powder selected from the group consisting of Ni, Pd, Pt, Au, Ag, Cu and alloys thereof. The conductive slurry for gravure printing as described in claim 1 or 7, wherein the average particle size of the conductive powder is greater than 0.05 μm and less than 1.0 μm. The conductive slurry for gravure printing as described in claim 1 or 7, wherein the ceramic powder contains barium titanium oxide. The conductive slurry for gravure printing as described in claim 1 or 7, wherein the average particle size of the ceramic powder is greater than 0.01 μm and less than 0.5 μm. The conductive slurry for gravure printing as described in claim 1 or 7 contains the ceramic powder in an amount of 1% by mass to 20% by mass relative to the conductive slurry as a whole. The conductive paste for gravure printing as described in claim 1 or 7, wherein the binder resin contains a cellulose-based resin. The conductive slurry for gravure printing as described in claim 7, wherein the viscosity is less than 3 Pa.S at a shear rate of 100 sec ^-1 and the viscosity is less than 1 Pa.S at a shear rate of 10000 sec ^-1 . The conductive slurry for gravure printing as described in claim 1 or 7, wherein the average height (Wc) of the waviness curve element of the dry film obtained by gravure printing the conductive slurry under the conditions of a printing speed of 30 m/min and a film thickness of 0.50 μm to 2 μm is 0.5 μm or less. An electronic component, characterized in that the electronic component is an electronic component formed using the conductive slurry for gravure printing described in any one of claims 1 to 16. A multilayer ceramic capacitor, characterized in that the multilayer ceramic capacitor has at least a multilayer body formed by laminating a dielectric layer and an internal electrode layer, and the internal electrode layer is formed using the conductive slurry for gravure printing described in any one of claims 1 to 16.

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