JP6754852B2 - Conductive composition - Google Patents

Description

The present disclosure relates to conductive compositions.

Conventionally, as a conductive material for producing a composite of a ceramic and a conductor, such as when forming an electrode or a circuit on the surface of a ceramic substrate, metal particles such as Ag, Cu, Ni or Pt and a glass powder having a low softening point are used. A conductive composition in which and is mixed in an organic vehicle is generally known. As a method for producing a composite of ceramic and a conductor, a method of simultaneously firing a green sheet (dielectric sheet) containing ceramic and a conductive composition (cofire method) is known. For example, a chip laminated ceramic capacitor is manufactured by printing a conductive composition for an electrode layer on a green sheet by a screen printing method and then performing a firing step at a high temperature of about 1000 ° C.

Such a conductive composition is required to have excellent adhesion to a ceramic substrate after firing. Therefore, for example, Japanese Patent Application Laid-Open No. 2006-73836 (Patent Document 1) describes a conductive composition for ceramic electronic components containing rosin or terpene oil polymerized resin that can be obtained from pine resin in order to improve the adhesion to the ceramic body. Is disclosed.

Further, when a composite of a ceramic and a conductor is produced by the cofire method, it is known that it is useful to increase the sintering delay of the conductive composition in order to improve the adhesion to the ceramic substrate. According to Japanese Patent No. 5986117 (Patent Document 2), by mixing copper powder and an aqueous solution of aminosilane and adsorbing aminosilane on the surface of copper powder, there is no aggregation after surface treatment and the sintering delay property is dramatically increased. It is disclosed that it will improve. Claim 1 of the document states that "the amount of adhesion of any one or more of Si, Ti, Al, Zr, Ce, and Sn is 200 to 16000 μg with respect to 1 g of the metal powder, and the weight% of N with respect to the metal powder is A surface-treated metal powder having a content of 0.02% or more, the surface-treated metal powder is a metal powder surface-treated with a coupling agent, and the coupling agent has an amino group at the end. A surface-treated metal powder that is a coupling agent. "

Japanese Unexamined Patent Publication No. 2006-73836 Japanese Patent No. 5986117

By the way, in the case of industrially producing a composite of a ceramic and a conductor, it is of course an important characteristic that the adhesion between the two is high, but not only that, but also the high conductivity and high productivity of the conductor. It is desirable to have more.

Therefore, an object of the present disclosure in one aspect is to provide a conductive composition having the following three properties.
(1) The conductor obtained by sintering is excellent in conductivity.
(2) Contributes to improving the productivity of the composite of ceramic and conductor.
(3) Excellent adhesion to ceramic when a composite of ceramic and conductor is manufactured by the cofire method.

In order to solve the above problems, the present inventor first examined the improvement of productivity in the case of producing a composite of a ceramic and a conductor by using the cofire method. Then, they have found that it is effective to bake in a steam atmosphere in order to improve the desorption rate of the binder resin contained in the green sheet and the binder resin contained in the conductive composition. This is due to the large permeation action of the heated steam into the object to be fired.

Next, the present inventor examined means for improving the adhesion between the ceramic and the conductor. In order to suppress peeling between the ceramic and the conductor during the cooling process after firing (≈ deterioration of adhesion), it is possible to reduce the difference in heat shrinkage behavior between the metal powder contained in the conductive composition and the ceramic. Desired. As one of the means, it is effective to raise the sintering start temperature of the metal powder contained in the conductive composition, in other words, to increase the sintering delay property. Patent Document 2 discloses a technique of delaying the sintering start temperature of a metal powder by adhering aminosilane to the metal powder.

Therefore, it is considered that both adhesion and productivity can be achieved by simultaneously firing the conductive composition containing the metal powder to which aminosilane is attached and the green sheet in a steam atmosphere. However, the inventor has found that the sintering delay of a metal powder surface-treated with a coupling agent, not limited to aminosilane, tends to deteriorate in a water vapor atmosphere.

FIG. 1 is a diagram showing the atmosphere dependence of the TMA (Thermomechanical Analyzer) behavior of copper powder to which 1300 mass ppm of Si is attached using aminosilane. The line "0 kPa" represents the TMA behavior of the copper powder in 100% nitrogen (= non-water vapor atmosphere). The line of "10 kPa" represents the TMA behavior of the copper powder at a water vapor partial pressure of 0.1 atm (residual nitrogen). As shown in FIG. 1, it can be seen that the sintering start temperature of the copper powder was about 900 ° C. in the non-steam atmosphere, whereas it decreased to less than 600 ° C. in the steam atmosphere.

The inventor found that as a result of the copper (metal) -Si bond and the Si-Si bond being decomposed by heated steam, the copper (metal) layer not covered with Si was exposed, and the exposed copper ( It is believed that the cause is that sintering is started when the metal particles come into contact with each other (FIGS. 2 and 3). Therefore, the inventor diligently studied measures to prevent the sintering delay from deteriorating even in a water vapor atmosphere. Surprisingly, by promoting the self-condensation reaction of the coupling agent more than before, the water vapor atmosphere It was found that the decrease in the sintering start temperature in the sintering in the above can be suppressed.

Usually, the coupling agent is subjected to a coupling reaction with a metal powder after stirring overnight in a state of being adjusted to an acidic solution in order to suppress the self-condensation reaction. On the other hand, the inventor dared to stir the coupling agent under a strong alkali of pH 11.5 or more and 13.5 or less to positively promote the self-condensation reaction of the coupling agent, and then combine it with the metal powder. When the coupling reaction was carried out, it was found that the decrease in the sintering start temperature during sintering in a steam atmosphere was suppressed. Although it is not intended that the present invention is limited by theory, oxides derived from coupling agents that are firmly bonded to each other on the surface of metal fine particles by promoting the self-condensation reaction of the coupling agent in advance. It is considered that multiple layers are formed and it is possible to suppress a decrease in the sintering start temperature during sintering in a water vapor atmosphere.

The effect of performing the coupling reaction with the metal powder after promoting the self-condensation reaction of the coupling agent is not exhibited only in aminosilane. In Patent Document 2, it was confirmed that even a coupling agent other than aminosilane, which had almost no sintering delay, exhibited excellent sintering delay.

The present invention has been completed based on the above findings, and is exemplified below.
(1)
A conductive composition containing a metal powder, a binder resin, and a dispersion medium.
A sintered body obtained by heating the conductive composition to 850 ° C. with a residual nitrogen atmosphere of a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at a heating rate of 1 ° C./min and firing at 850 ° C. for 30 minutes. The total concentration of Si, Ti, Al and Zr was 1000 to 10000 mass ppm when measured by ICP emission spectroscopic analysis.
The conductive composition is applied onto a slide glass at a moving speed of 5 cm / sec using an applicator with a 25 μm gap, dried at 120 ° C. for 10 minutes, and then coated with a stylus type roughness meter. Arithmetic mean roughness Ra in the direction is 0.2 μm or less,
From 0.5 g of the powder obtained by crushing the coating film, a columnar green compact having a density of 4.7 ± 0.2 gcm ^-3 and a diameter of 5 mm was formed, and a load of 98 mN was applied to the green compact. Conductivity with a volume shrinkage of 15% or less at 650 ° C. when TMA measured at a heating rate of 1 ° C./min in a residual nitrogen atmosphere with a total pressure of 1 atm and a partial pressure of water vapor of 0.05 atm while being applied to the upper and lower surfaces. Composition.
(2)
A sintered body obtained by heating the conductive composition to a total pressure of 1 atm, a steam partial pressure of 0.03 atm, a residual nitrogen atmosphere, a rate of 0.75 ° C./min to 850 ° C., and firing at 850 ° C. for 20 minutes. The conductive composition according to (1), wherein the specific resistance of the above is 3.0 μΩ · cm or less.
(3)
The conductive composition according to (1) or (2), wherein the metal powder is a metal powder surface-treated with a coupling agent having an amino group at the end.
(4)
The conductive composition according to (3), wherein the coupling agent contains at least one of monoaminosilane and diaminosilane.
(5)
The conductive composition according to any one of (1) to (4), wherein the metal powder contains copper powder.
(6)
A sintered body obtained by heating the conductive composition to 850 ° C. with a residual nitrogen atmosphere of a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at a heating rate of 1 ° C./min and firing at 850 ° C. for 30 minutes. The conductive composition according to any one of (1) to (5), wherein the concentration of Si when measured by ICP emission spectroscopic analysis is 1000 to 10000 mass ppm.
(7)
A composite of a ceramic and a conductor produced by using the conductive composition according to any one of (1) to (6).
(8)
A monolithic ceramic capacitor manufactured by using the conductive composition according to any one of (1) to (6).
(9)
A ceramic circuit board manufactured by using the conductive composition according to any one of (1) to (6).

In one embodiment, the conductive composition according to the present disclosure is excellent in conductivity when made into a sintered body. Further, in one embodiment, the conductive composition according to the present disclosure is suitable for firing in a steam atmosphere for improving productivity. Further, in one embodiment, the conductive composition according to the present disclosure is excellent in adhesion to the ceramic when a composite of the ceramic and the conductor is produced by the cofire method.

It is a graph which shows the atmosphere dependence of the TMA (Thermomechanical Analyzer) behavior of the copper powder which attached 1300 mass ppm of Si. It is a conceptual diagram which shows the bonding state between copper (metal) -Si and Si-Si about the silane coupling agent adhering to a metal surface. It is a conceptual diagram which shows the state which the bond between copper (metal) -Si and Si-Si is decomposed about the silane coupling agent adhering to a copper metal surface.

The present disclosure will be described in detail below with reference to embodiments. The present disclosure is not limited to the specific embodiments listed below.

[Conductive composition]
In one embodiment, the conductive composition according to the present disclosure contains a metal powder, a binder resin, and a dispersion medium. The conductive composition can be produced by kneading these various components. Kneading can be performed using known means. The conductive composition is provided as a paste in one embodiment.

In one embodiment, the conductive composition according to the present disclosure can be used to produce a composite of a ceramic and a conductor. As a method for producing a composite of ceramic and a conductor, a method of simultaneously firing a green sheet (dielectric sheet) containing ceramic and a conductive composition (cofire method) can be preferably adopted. In particular, by using the conductive composition according to the present disclosure, even if firing is performed in a steam atmosphere in order to increase productivity, the specific resistance of the conductor is small and the adhesion between the ceramic and the conductor is improved. An excellent conductor-ceramic composite can be obtained. This property is at least partially due to the fact that the metal powder contained in the conductive composition has excellent sintering delay even in a water vapor atmosphere.

Since the sintered body obtained by firing the conductive composition according to the present disclosure is a conductor, it can be used as, for example, an electrode or a circuit. For example, a multilayer ceramic capacitor can be manufactured by applying a conductive composition for an electrode layer on a green sheet by a screen printing method or the like, and then subjecting it to a firing step of, for example, 500 to 1000 ° C. In this case, the sintered body of the conductive composition is used as an internal electrode of a monolithic ceramic capacitor. Similarly, the ceramic circuit board can be manufactured by applying a conductive composition for circuit formation on a green sheet by a screen printing method or the like, and then undergoing a firing step of, for example, 400 to 1000 ° C.

[Metal powder]
As the metal powder, for example, one or more kinds of metal powder selected from the group consisting of Pt powder, Pd powder, Ag powder, Ni powder and Cu powder can be used. In a preferred embodiment, one or more metal powders selected from the group consisting of Ag powder, Ni powder and Cu powder can be used. A typical example is Cu powder (copper powder). The Pt powder contains pure Pt powder and Pt alloy powder (particularly Pt alloy powder having a Pt content of 80% by mass or more), and the Pd powder contains pure Pd powder and Pd alloy powder (particularly Pd content of 80% by mass). The above Pd alloy powder) is included, the Ag powder contains pure Ag powder and Ag alloy powder (particularly Ag alloy powder having an Ag content of 80% by mass or more), and the Ni powder contains pure Ni powder and Ni alloy. Powder (particularly Ni alloy powder having a Ni content of 80% by mass or more) is included, and Cu powder includes pure Cu powder and Cu alloy powder (particularly Cu alloy powder having a Cu content of 80% by mass or more).

The BET specific surface area of the metal powder can be 2 m ² g ^-1 or more and 20 m ² g ^-1 or less, more preferably 3 m ² g ^-1 or more and 20 m ² g ^-1 or less. For example, when the conductive composition is used as an internal electrode of a multilayer ceramic capacitor, it is required to make the electrode layer thin in order to realize a small size and a high capacity. In that sense, it is preferable that the BET specific surface area of the metal powder is large. On the other hand, although no particular inconvenience due to the large BET specific surface area can be considered, it is practically difficult to produce a metal powder of 20 m ² g ^-1 or more. The BET specific surface area is measured according to JIS Z 8830: 2013 after degassing the metal powder in vacuum at 200 ° C. for 5 hours. The BET specific surface area can be measured using, for example, BELSORP-miniII manufactured by Microtrac Bell.

The D50 of the metal powder is preferably 0.1 to 0.8 μm, more preferably 0.1 to 0.5 μm. If the D50 of the metal powder is too small, it tends to aggregate and the dispersibility of the metal powder in the conductive composition may decrease. On the other hand, if the D50 of the metal powder is too large, the coating film roughness of the conductive composition becomes coarse, and the adhesion between the ceramic and the conductor may decrease. Here, D50 of the metal powder refers to a volume-based median diameter obtained by laser diffraction type particle size distribution measurement.

The concentration of the metal powder in the conductive composition is preferably 30% by mass or more, more preferably 35% by mass or more, from the viewpoint of improving the coating film density and, by extension, the electrode density. The concentration of the metal powder in the conductive composition is preferably 90% by mass or less, more preferably 85% by mass or less, from the viewpoint of printability.

As the metal powder, either a metal powder produced by a dry method or a metal powder produced by a wet method can be used. When a metal powder produced by a wet method is used, it is preferable in that a wet process is performed consistently including surface treatment with a coupling agent described later.

A suitable method for producing copper powder by a wet method will be exemplified. The production method involves adding a dispersant (for example, gum arabic, gelatin, collagen peptide, surfactant, etc.) to the cuprous oxide slurry, and then adding dilute sulfuric acid to the slurry at once within 5 seconds. The step of performing the disproportionation reaction is included. In a preferred embodiment, the slurry can be kept at room temperature (20 to 25 ° C.) or lower, and dilute sulfuric acid similarly kept at room temperature or lower can be added to carry out a disproportionation reaction. The BET specific surface area (size) of the copper powder can be controlled by the addition amount of the dispersant, the addition rate of dilute sulfuric acid, and the like. As an example, when the amount of organic matter such as gum arabic is large, the BET specific surface area tends to be large, and when the addition rate of dilute sulfuric acid is high, the BET specific surface area tends to be large. In a preferred embodiment, the dilute sulfuric acid can be added so that the slurry has a pH of 2.5 or less, preferably pH 2.0 or less, and more preferably pH 1.5 or less. In a preferred embodiment, the addition of dilute sulfuric acid to the slurry should be within 5 minutes, preferably within 1 minute, more preferably within 30 seconds, even more preferably within 10 seconds, even more preferably within 5 seconds. , Can be added. In a preferred embodiment, the disproportionation reaction can be completed within 10 minutes, for example, within 5 seconds if the addition of dilute sulfuric acid to the slurry is instantaneous. In a preferred embodiment, the concentration of the dispersant such as gum arabic in the slurry before the addition of dilute sulfuric acid can be 0.2 to 1.2 g / L. The principle of this disproportionation reaction is as follows:
Cu ₂ O + H ₂ SO ₄ → Cu ↓ + Cu SO ₄ + H ₂ O
The copper powder obtained by this disproportionation can be washed, rust-proofed, filtered, dried, crushed, and classified if desired, and then mixed with the coupling agent aqueous solution, but if desired, it is washed. The metal powder slurry obtained after performing rust prevention and filtration may be mixed with the coupling agent aqueous solution as it is without drying.

It is desirable that the metal powder is surface-treated with a coupling agent. Specifically, it is more preferable that the surface is treated with a coupling agent containing one or more elements selected from the group consisting of Si, Ti, Al and Zr. When the metal powder has undergone a suitable surface treatment with a coupling agent, a conductive composition that satisfies the following three requirements can be obtained. By using a conductive composition that satisfies these three requirements, even if firing is performed in a steam atmosphere, the specific resistance of the conductor is small, and the conductor ceramics have excellent adhesion between the conductors. A complex can be obtained.

(Requirement 1)
A sintered body obtained by heating the conductive composition to 850 ° C. at a heating rate of 1 ° C./min at a residual nitrogen atmosphere with a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm, and firing at 850 ° C. for 30 minutes. The total concentration of Si, Ti, Al and Zr as measured by ICP emission spectroscopic analysis is 1000-10000 mass ppm. If the total concentration is too small, it is difficult to sufficiently exhibit the sintering delay property in a water vapor atmosphere. On the other hand, if the total concentration is too high, the conductivity and heat dissipation of the sintered body tend to deteriorate. The total concentration is preferably 1500 to 7000 mass ppm, more preferably 1500 to 5000 mass ppm.

(Requirement 2)
The conductive composition is applied onto a slide glass at a moving speed of 5 cm / sec using an applicator with a 25 μm gap, dried at 120 ° C. for 10 minutes, and then coated with a stylus type roughness meter. The arithmetic average roughness Ra of is 0.2 μm or less. The arithmetic average roughness Ra is expressed as an average value when measured at a plurality of locations with a stylus type roughness meter in accordance with JIS B0633: 2001. The small arithmetic mean roughness Ra means that the metal powder is properly treated with the coupling agent and the metal powder has high dispersibility in the conductive composition. When the dispersibility of the metal powder decreases and aggregates, the arithmetic mean roughness Ra tends to increase. In this case, due to the formation of voids between the ceramic and the conductor, the adhesion between them is lowered and the conductivity of the conductor is deteriorated. The arithmetic mean roughness Ra is preferably 0.2 μm or less, and more preferably 0.1 μm or less.

(Requirement 3)
From 0.5 g of powder obtained by applying the conductive composition onto a slide glass at a moving speed of 5 cm / sec using a 25 μm-thick applicator, drying at 120 ° C. for 10 minutes, and then crushing the coating film. A columnar green compact with a diameter of 5 mm was formed at a density of 4.7 ± 0.2 gcm ^-3 , and while applying a load of 98 mN to the upper and lower surfaces of the green compact, the total pressure was 1 atm and the partial pressure of water vapor was 0.05 atm. The volume shrinkage at 650 ° C. is 15% or less when TMA is measured at a heating rate of 1 ° C./min in the residual nitrogen atmosphere of. When the volume shrinkage ratio is small, it means that the sintering delay property in a water vapor atmosphere is excellent. The volume shrinkage is preferably 15% or less, and more preferably 10% or less. The volume shrinkage is most preferably 0%, but is usually 2% or more, typically 5% or more.

In a preferred embodiment, the conductive composition is heated to 850 ° C. at a rate of 0.75 ° C./min and calcined at 850 ° C. for 20 minutes in a residual nitrogen atmosphere with a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm. The specific resistance of the sintered body thus obtained is 3.0 μΩ · cm or less, more preferably 2.5 μΩ · cm or less, still more preferably 2.0 μΩ · cm or less, for example, 1. It can be 0 to 3.0 μΩ · cm.

Examples of the coupling agent include a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, and a zirconate coupling agent. One type of coupling agent may be used, or two or more types may be used in combination. As the coupling agent, Si was used when a silane coupling agent was used, Ti was used when a titanate coupling agent was used, Al was used when an aluminate coupling agent was used, and a zirconate coupling agent was used. In some cases, Zr can be attached to the surface of the metal powder, respectively.

As the silane coupling agent, aminosilane can be preferably used. In a preferred embodiment, a silane containing one or more amino groups and / or imino groups can be used as the aminosilane. The number of amino groups and imino groups contained in aminosilane can be, for example, 1 to 4, preferably 1-3, and more preferably 1-2. In a preferred embodiment, the number of amino groups and imino groups contained in aminosilane can be one each. Aminosilane having a total number of amino groups and imino groups contained in aminosilane of 1 can be referred to as monoaminosilane in particular, aminosilane having 2 can be referred to as diaminosilane, and aminosilane having 3 can be referred to as triaminosilane. .. In particular, monoaminosilane and diaminosilane can be preferably used. In a preferred embodiment, a monoaminosilane containing one amino group can be used as the aminosilane. In a preferred embodiment, the aminosilane can contain at least one, eg, one amino group, at the end of the molecule, preferably at the end of a linear or branched chain molecule.

Examples of the aminosilane include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 1-. Aminopropyltrimethoxysilane, 2-aminopropyltrimethoxysilane, 1,2-diaminopropyltrimethoxysilane, 3-amino-1-propenyltrimethoxysilane, 3-amino-1-propynyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl- 3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3- (N-phenyl) amino Propyltrimethoxysilane can be mentioned.

In a preferred embodiment, the aminosilane represented by the following formula I can be used.
H ₂ N-R ^1- Si (OR ² ) ₂ (R ³ ) (Formula I)
In the above formula I
R ¹ is a hydrocarbon of C1 to C12 having a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or heterocyclic. It is a divalent group of
R ² is an alkyl group of C1 to C5.
R ³ is an alkyl group of C1 to C5 or an alkoxy group of C1 to C5.

In a preferred embodiment, R ¹ of the above formula I has a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or heterocyclic ring. It is a divalent group of C1 to C12 hydrocarbons without, and more preferably R ¹ is a substituted or unsubstituted divalent group of C1 to C12 linear saturated hydrocarbons, substituted or unsubstituted. C1 to C12 branched saturated hydrocarbon divalent groups, substituted or unsubstituted, C1 to C12 linear unsaturated hydrocarbon divalent groups, substituted or unsubstituted, C1 to C12 Divalent groups of branched unsaturated hydrocarbons, substituted or unsubstituted, divalent groups of cyclic hydrocarbons of C1 to C12, substituted or unsubstituted, divalent groups of heterocyclic hydrocarbons of C1 to C12, It can be a group selected from the group consisting of substituted or unsubstituted divalent groups of aromatic hydrocarbons of C1 to C12. In a preferred embodiment, R ¹ of the above formula I is a divalent group of saturated or unsaturated chain hydrocarbons of C1 to C12, more preferably atoms at both ends of the chain structure are free atoms. It is a divalent group with a value. In a preferred embodiment, the number of carbon atoms of the divalent group can be, for example, C1 to C12, preferably C1 to C8, preferably C1 to C6, and preferably C1 to C3.

In a preferred embodiment, R ¹ of the above formula I is − (CH ₂ ) _n −, − (CH ₂ ) _n − (CH) _m − (CH ₂ ) _j-1 −, − (CH ₂ ) _n −. (CC) − (CH ₂ ) _n-1 −, − (CH ₂ ) _n −NH − (CH ₂ ) _m −, − (CH ₂ ) _n −NH − (CH ₂ ) _m −NH − (CH ₂ ) _j −, − (CH ₂ ) _n-1 − (CH) NH ₂ − (CH ₂ ) _m-1 −, − (CH ₂ ) _n-1 − (CH) NH ₂ − (CH ₂ ) _m-1 − It can be a group selected from the group consisting of NH − (CH ₂ ) _j − (where n, m, j are integers greater than or equal to 1). (However, (CC) above represents a triple bond of C and C.) In a preferred embodiment, R ¹ is − (CH ₂ ) n− or − (CH ₂ ) n—NH− (CH _2). ) M-. (However, the above (CC) represents a triple bond of C and C.) In a preferred embodiment, the hydrogen of the above divalent group R ¹ may be substituted with an amino group, for example 1 ~ 3 hydrogens, such as 1-2 hydrogens, such as 1 hydrogen, may be substituted with amino groups.

In a preferred embodiment, n, m, and j of the above formula I may be independently set to an integer of 1 or more and 12 or less, preferably an integer of 1 or more and 6 or less, and more preferably an integer of 1 or more and 4 or less. It can be, for example, an integer selected from 1, 2, 3, 4 and can be, for example, 1, 2 or 3.

In a preferred embodiment, R ² of the above formula I can be an alkyl group of C1 to C5, preferably an alkyl group of C1 to C3, more preferably an alkyl group of C1 to C2, for example, a methyl group. It can be an ethyl group, an isopropyl group, or a propyl group, preferably a methyl group or an ethyl group.

In a preferred embodiment, R ³ of the above formula I can be an alkyl group of C1 to C5, preferably an alkyl group of C1 to C3, and more preferably an alkyl group of C1 to C2, for example. , Methyl group, ethyl group, isopropyl group, or propyl group, preferably methyl group or ethyl group. Further, R ^{3 of the} above formula I can be an alkoxy group of C1 to C5, preferably an alkoxy group of C1 to C3, more preferably an alkoxy group of C1 to C2, and for example, a methoxy group. It can be an ethoxy group, an isopropoxy group, or a propoxy group, preferably a methoxy group or an ethoxy group.

Examples of the titanate-based coupling agent include the following formula II:
(H ₂ N-R ^1- O) _p Ti (OR ² ) _q (Equation II)
(However, in the above formula II,
R ¹ is a hydrocarbon of C1 to C12 having a linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, heterocyclic or heterocyclic. It is a divalent group of
R ² is a linear or branched alkyl group of C1 to C5.
p and q are integers of 1 to 3 and p + q = 4. )
Examples thereof include amino group-containing titanates represented by.

The R ¹ in the formula II, can be preferably used a group exemplified as R ¹ in formula I. As R ¹ of the above formula II, for example, − (CH ₂ ) _n −, − (CH ₂ ) _n − (CH) _m − (CH ₂ ) _j-1 −, − (CH ₂ ) _n − (CC) − (CH ₂ ) _n-1 −, − (CH ₂ ) _n −NH − (CH ₂ ) _m −, − (CH ₂ ) _n −NH − (CH ₂ ) _m −NH − (CH ₂ ) _j −, − (CH ₂ ) _n-1 − (CH) NH ₂ − (CH ₂ ) _m-1 −, − (CH ₂ ) _n-1 − (CH) NH ₂ − (CH ₂ ) _m-1 − NH − (CH ₂ ) ₂ ) It can be a group selected from the group consisting of _j − (where n, m, j are integers of 1 or more). As a particularly suitable R ₁ , − (CH ₂ ) _n −NH − (CH ₂ ) _m − (where n + m = 4, particularly preferably n = m = 2) can be mentioned.

The R ² of the formula II, can be preferably used a group exemplified as R ² in formula I. In a preferred embodiment, an alkyl group of C3 can be mentioned, and particularly preferably a propyl group and an isopropyl group. P and q in the above formula II are integers of 1 to 3, p + q = 4, and preferably a combination of p = q = 2 and a combination of p = 3 and q = 1.

In the above, the description has been made using a coupling agent having an amino group at the end, but the surface treatment of the metal powder with the coupling agent uses a coupling agent (non-amino acid-based coupling agent) having no amino group at the end. However, it can be preferably carried out. Examples of the non-amino coupling agent include a coupling agent having an organic functional group such as an epoxy group, a mercapto group, an acryloyl group, a methacryloyl group, a vinyl group and an acid anhydride group at the terminal.

Examples of the silane coupling agent having an epoxy group include 3-glycidoxytrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxy. Examples thereof include silane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

Examples of the silane coupling agent having a mercapto group include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

Examples of the silane coupling agent having an acryloyl group include 3-acryloxypropyltrimethoxysilane.

Examples of the silane coupling agent having a methacryloyl group include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Can be mentioned.

Examples of the silane coupling agent having a vinyl group include vinyltrimethoxysilane and vinyltriethoxysilane.

Examples of the silane coupling agent having an acid anhydride group include 3-trimethoxysilylpropyl succinic anhydride.

The coupling agent is preferably pretreated to promote the self-condensation reaction before being mixed with the metal powder. In one embodiment, the pretreatment involves adding an alkaline aqueous solution such as aqueous ammonia, aqueous NaOH, aqueous KOH, or aqueous monoethanolamine to the coupling agent, preferably pH 11.5 or more and 13.5 or less, more preferably pH 12. It includes a step of preparing an aqueous solution of a coupling agent adjusted to 0.0 or more and 13.5 or less, and a step of stirring the aqueous solution of the coupling agent while maintaining it at 10 ° C. to 40 ° C.

The higher the pH, the more the self-condensation reaction of the coupling agent can be promoted. However, if the self-condensation reaction is promoted too much, the coupling agent gels and the dispersibility of the metal powder decreases. As a result, the coating film becomes rough. Further, the longer the stirring time, the more the self-condensation reaction can be promoted, but the longer the stirring time, the lower the productivity. Therefore, the stirring time can be preferably 1 to 72 hours, more preferably 6 to 24 hours.

The aqueous solution of the coupling agent after the pretreatment can be applied to the surface treatment of the metal powder by a known method. For example, the coupling reaction with the metal powder can be promoted by mixing the pretreated aqueous solution of the coupling agent with the metal powder to obtain a metal powder dispersion and then appropriately stirring the mixture by a known method. In a preferred embodiment, stirring can be performed, for example, at room temperature, for example, at temperatures in the range of 5-80 ° C, 10-40 ° C, 20-30 ° C. Further, stirring is preferably carried out for 1 minute or longer, and more preferably 30 minutes or longer, in order to promote the coupling reaction between the metal powder and the coupling agent.

The concentration of the coupling agent in the aqueous solution of the coupling agent is preferably 10% by volume or more, more preferably 20% by volume or more in order to promote the self-condensation reaction. Further, the concentration of the coupling agent in the aqueous solution of the coupling agent is preferably 60% by volume or less, preferably 45% by volume or less in order to prevent the self-condensation reaction from progressing excessively and gelling. Is more preferable.

In certain embodiments, stirring may be performed by sonication. The treatment time of the ultrasonic treatment is selected according to the state of the metal powder dispersion, but is preferably 1 to 180 minutes, more preferably 3 to 150 minutes, even more preferably 10 to 120 minutes, and most preferably 20 to 20 minutes. It can be 80 minutes. In a preferred embodiment, the sonication can be carried out at an output of preferably 50-600 W, more preferably 100-600 W per 100 mL. In a preferred embodiment, the sonication can be carried out at a frequency of preferably 10 to 1 MHz, more preferably 20 to 1 MHz, even more preferably 50 to 1 MHz.

After the surface treatment with the coupling agent, the surface-treated metal powder can be separated and recovered from the metal powder dispersion liquid. Known means can be used for this separation / recovery, and for example, filtration, centrifugation, decantation, or the like can be used. Following the separation / recovery, drying can be performed if desired. The higher the moisture content of the cake before drying, the higher the total concentration of Si, Ti, Al and Zr according to the above-mentioned "Requirement 1" is likely to be, and vice versa. However, this only causes the unreacted coupling agent to adhere to the cake and does not contribute much to the improvement of the sintering delay. Therefore, even if "Requirement 1" is satisfied, it does not necessarily satisfy "Requirement 3". In order to satisfy "Requirement 3" in addition to "Requirement 1", it is necessary that the self-condensation reaction of the silane coupling agent is properly performed.

Known means can be used for drying the cake, for example, drying by heating can be performed. The heat drying can be performed, for example, by heat treatment at a temperature of 50 to 400 ° C. and 60 to 350 ° C., for example, for 5 to 180 minutes and 30 to 120 minutes. Following the heat drying, the metal powder may be further crushed, if desired. Further, with respect to the recovered surface-treated metal powder, an organic substance or the like may be further adsorbed on the surface of the surface-treated metal powder for the purpose of preventing rust or improving dispersibility in the paste. ..

In certain embodiments, the surface-treated metal powder may be further surface-treated after being surface-treated with a coupling agent. Examples of such a surface treatment include a rust preventive treatment with an organic rust preventive agent such as benzotriazole and imidazole, and even by such a normal treatment, the surface treatment layer with a coupling agent is desorbed or the like. There is no such thing. Therefore, those skilled in the art can optionally perform such known surface treatments within the limits of not losing excellent sintering retardation. That is, the metal powder obtained by further surface-treating the surface of the surface-treated metal powder according to the present disclosure within the limit of not losing the excellent sintering delay property is also within the scope of the present disclosure. ..

[Binder resin]
Examples of the binder resin used in the conductive composition include cellulose resin, acrylic resin, alkyd resin, polyvinyl alcohol resin, polyvinyl acetal, ketone resin, urea resin, melamine resin, polyester, polyamide and polyurethane. it can. One type of binder resin may be used alone, or two or more types may be used in combination. The binder resin in the conductive composition can be contained in a ratio of, for example, 0.1 to 10%, preferably 1 to 8%, based on the mass of the metal powder. By setting the blending ratio of the binder resin in the above range, the structural stability and uniform coating property of the conductive composition can be improved.

[Dispersion medium]
As the dispersion medium used in the conductive composition, for example, one or more selected from the group consisting of alcohol solvents (for example, terpineol, dihydroterpineol, isopropyl alcohol, butylcarbitol, terpineloxyethanol, dihydroterpineloxyethanol). ), Glycol ether solvent (eg butyl carbitol), acetate solvent (eg butyl carbitol acetate, dihydroterpineol acetate, dihydrocarbitol acetate, carbitol acetate, linaryl acetate, turpinyl acetate 1) Species or more), ketone solvent (for example, methyl ethyl ketone), hydrocarbon solvent (for example, one or more selected from the group consisting of toluene and cyclohexane), cellosolves (for example, one or more selected from the group consisting of ethyl cellosolve and butyl cellosolve). , Diethylphthalate, or propineauto solvent (for example, one or more selected from the group consisting of dihydroterpinyl propine auto, dihydrocarbyl propine auto, and isobonyl propine auto). One type of dispersion medium may be used alone, or two or more types may be used in combination. The conductive composition may contain a dispersion medium at a ratio of, for example, 10 to 400% with respect to the mass of the metal powder.

[Other additives]
The conductive composition according to the present disclosure may appropriately contain known additives such as glass frit, dispersant, thickener and antifoaming agent.

Glass frits are useful for improving the adhesion between ceramics and conductors. As the glass frit, for example, a BET specific surface area of 1 to 10 m ² g ^-1, preferably 2 to 10 m ² g ^-1, more preferably may use a glass frit 2 to 8 m ² g ^-1. The conductive composition may contain glass frit at a ratio of, for example, 0 to 5% with respect to the mass of the metal powder.

Examples of the dispersant include oleic acid, stearic acid and oleylamine. The conductive composition may contain a dispersant so as to have a ratio of, for example, 0 to 5% with respect to the mass of the metal powder.

Examples of the defoaming agent include organically modified polysiloxane and polyacrylate. The conductive composition may contain an antifoaming agent so as to have a ratio of, for example, 0 to 5% with respect to the mass of the metal powder.

The composition of the conductive composition has been described above, but the composition other than the metal powder in the conductive composition (for example, binder resin type, dispersion medium resin type, binder resin ratio in the conductive composition, conductive composition). The dispersion medium ratio in the above) can be appropriately selected as long as the printability on the green sheet to be fired at the same time as the conductive composition is not impaired.

The present disclosure will be described in more detail with reference to examples below. The present disclosure is not limited to the following examples.

(Examples 1 to 8, Comparative Examples 1 to 6)
[Copper powder]
6 L of pure water was added to a 50 L container and heated so that the liquid temperature became 70 ° C. 3.49 kg of copper sulfate pentahydrate was added thereto, and it was visually confirmed that all the copper sulfate crystals were dissolved while stirring at 350 rpm. 1.39 kg of D-glucose was added thereto. A 5 wt% aqueous ammonia solution was added thereto by a liquid feed pump at a rate of 300 mL / min until pH 5 was reached. When the pH reached 5, the aqueous ammonia solution was added dropwise with a dropper to raise the pH to 8.4. From here, the liquid temperature was maintained at 70 ± 2 ° C. and pH 8.5 ± 0.1 for 3 hours. The pH was adjusted with an aqueous ammonia solution. After completion of the reaction, decantation, discharge of the supernatant, and washing with pure water were repeated until the pH of the supernatant fell below 8.0 to obtain a cuprous oxide powder slurry. A part of the solid content was taken out and dried in nitrogen at 70 ° C., and it was confirmed by XRD that this solid content was cuprous oxide.

The water content of the cuprous oxide powder slurry obtained above was adjusted to 20% by mass, and pure water (25) was added to the cuprous oxide powder slurry (25 ° C.) so that the water content was 7 L per 1 kg of solid content. ℃) was added, 4 g of Nikawa was further added, and the mixture was stirred at 500 rpm. To this, 2 L (25 ° C.) of 25 vol% dilute sulfuric acid was instantaneously added to adjust the pH to 0.7. The powder was precipitated by decantation, the supernatant was drained, 7 L of pure water (25 ° C.) was added, and the mixture was stirred at 500 rpm for 10 minutes. The decantation and washing operations were repeated until the Cu concentration derived from Cu ^{2+ in the} supernatant was less than 1 g / L to obtain a copper powder slurry having a water content of 20% by mass.

A part of the obtained solid content was taken out and dried in nitrogen at 70 ° C., and it was confirmed by XRD that this solid content was copper. Further, after degassing the solid copper powder at 200 ° C. for 5 hours in a vacuum, the BET specific surface area was measured using BELSORP-miniII manufactured by Microtrac Bell Co., Ltd., and it was 3.2 m ² · g ^-1. Met. Further, the volume-based median diameter (D50) of the obtained solid copper powder was measured by a laser diffraction type particle size distribution measurement (MASTERSIER3000 manufactured by Malvern PANalytical Co., Ltd.). When a copper powder slurry was added to a 0.2 wt% sodium hexametaphosphate aqueous solution and the slurry was irradiated with ultrasonic waves while being heated at 40 ° C., the D50 was 0.4 μm.

[Manufacturing of surface-treated copper powder]
As a coupling agent, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) (hereinafter referred to as "diaminosilane") was prepared. This coupling agent and pure water were mixed, and the pH was further adjusted to the predetermined pH shown in Table 1 with aqueous ammonia to obtain an aqueous solution of the coupling agent. The self-condensation reaction of the coupling agent was promoted by stirring this at 25 ° C. for 14 hours. Next, the pretreated aqueous solution and 550 g of the copper powder slurry having a water content of 20% by mass were mixed and stirred at 25 ° C. and 500 rpm for 1 hour. Table 1 shows the diaminosilane concentration in the aqueous coupling agent solution. After stirring, solid-liquid separation was performed by suction filtration, and the copper powder was recovered as a cake having a predetermined water content (“pre-drying cake water content” in the table). The moisture content was confirmed by drying at 100 ° C. using an infrared moisture meter FD-660. The obtained cake was dried at 100 ° C. for 2 hours in a nitrogen atmosphere. The obtained dry powder was crushed in a mortar and pestle until it passed through a sieve having a hole of 0.7 mm, and further crushed by a jet mill. In this way, a surface-treated copper powder was obtained.

(Example 9)
As nickel powder, NF32 (D50 = 0.3 μm, BET specific surface area = 3.3 m ² · g ^-1 ) manufactured by Toho Titanium Co., Ltd. was prepared, and pure water was added to prepare a nickel powder slurry having a water content of 20% by mass. Prepared. Then, a surface-treated nickel powder was obtained by the same procedure as in Example 1.

(Example 10)
126 g of silver nitrate was dissolved in 8 L of pure water, 0.24 L of 25% ammonia water and 0.4 kg of ammonium nitrate were added to prepare a silver ammine complex salt aqueous solution. Gelatin was added to this at a ratio of 1 g / L, and this was used as an electrolytic solution. Using a DSE electrode plate for both the anode and cathode, electrolysis was performed at a current density of 200 Am- ² and a solution temperature of 20 ° C. Electrolysis was performed for 1 hour while scraping from the electrode plate. The silver powder thus obtained was filtered through Nutche and washed with pure water to obtain a silver powder slurry having a water content of 20% by mass. A part of the obtained solid content was taken out and dried in nitrogen at 70 ° C., and it was confirmed by XRD that this solid content was silver. Further, when the volume-based median diameter (D50) of silver powder as a solid content was determined by the same procedure as in Example 1, it was 0.2 μm. The BET specific surface area of silver powder, which is a solid content, was determined by the same procedure as in Example 1 and found to be 3.7 m ² · g ^-1 .

The silver powder slurry having a water content of 20% by mass obtained above was surface-treated in the same procedure as in Example 1 to obtain surface-treated silver powder.

(Example 11, Comparative Example 7)
The surface-treated copper powder was prepared in the same procedure as in Example 1 except that 3-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) (hereinafter referred to as "epoxysilane") was used as the coupling agent. Made.

(Example 12)
Implementation except that titanium aminoethylaminoethanolate (manufactured by Matsumoto Fine Chemicals, Organix TC-510) (hereinafter referred to as "TC-510 (titanate)") represented by the following chemical formula was used as the coupling agent. A surface-treated copper powder was prepared in the same procedure as in Example 1.

(Example 13)
As a coupling agent, titanium diisopropoxybis (triethanolamineate) (manufactured by Matsumoto Fine Chemicals, Organics TC-400) (hereinafter referred to as "TC-400 (titanate)") represented by the following chemical formula is used. A surface-treated copper powder was prepared in the same procedure as in Example 1 except for the above.

(Example 14)
As a coupling agent, diaminosilane and a zirconium lactate ammonium salt (manufactured by Matsumoto Fine Chemicals, Organtics ZC-300) (hereinafter referred to as "ZC-300") represented by the following chemical formula are mixed at a mass ratio of 70:30. A surface-treated copper powder was prepared in the same procedure as in Example 1 except that the copper powder was used.

[Making metal powder paste]
(Examples 1 to 7, Examples 9 to 14, Comparative Examples 1 to 7)
A vehicle was prepared by passing terpineol and ethyl cellulose through a rotation / revolution mixer AR-100 and three rolls and kneading them sufficiently. Next, the ratio of the vehicle, oleic acid, and the surface-treated metal powders of the above Examples and Comparative Examples was as follows: metal powder: ethyl cellulose: oleic acid: terpineol = 80: 2.3: 1.6: 16.1 After mixing so as to have a (mass ratio), pre-kneading with a rotation / revolution mixer, passing through 3 rolls (finishing roll gap 5 μm), defoaming using a rotation / revolution mixer, each metal of Examples and Comparative Examples. A powder paste was prepared.
(Example 8)
In the above procedure for preparing a metal powder paste, a paste was prepared according to the above procedure for producing a metal powder, except that the paste composition was metal powder: ethyl cellulose: terpineol = 35: 1.8: 63.2 (mass ratio).

[Analysis of metal concentration derived from coupling agent]
Each of the metal powder pastes of Examples and Comparative Examples obtained in the above procedure was heated to 850 ° C. at a residual nitrogen atmosphere of a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at a heating rate of 1 ° C./min to 850 ° C. The mixture was fired at ° C. for 30 minutes and then cooled to room temperature at a rate of 10 ° C./min to obtain a sintered body. This sintered body was dissolved with an acid, and the concentrations of Si, Ti, and Zr in the sintered body were analyzed by ICP emission spectroscopic analysis (ICP-OES manufactured by Hitachi High-Tech Science Co., Ltd.). The results are shown in Table 1. The table does not show the element concentration below the lower limit of detection.

[Surface roughness of coating film (Ra)]
Each of the metal powder pastes of Examples and Comparative Examples obtained in the above procedure was applied onto a slide glass at a moving speed of 5 cm / sec using an applicator with a 25 μm gap, and dried at 120 ° C. for 10 minutes. Ra (JIS B0633: 2001 compliant) in the coating direction of the obtained coating film was measured at 5 points with a stylus type roughness meter, and the average value was taken as the measured value. The results are shown in Table 1.

[Evaluation of volume shrinkage (sintering delay) during firing]
The dry coating film obtained in the surface roughness measurement test is peeled off from the slide glass, sufficiently crushed with a pestle and a mortar, and 0.5 g of the obtained powder is hand-pressed with a mold having an inner diameter of φ5 mm and 4.7. A columnar green compact having a density of ± 0.2 gcm ^-3 was formed. This green compact is removed from the mold, loaded into a thermomechanical analyzer (TMA4000 (Netch Japan)) so that the central axis is in the vertical direction, and the total pressure is 1 atm with a steam generator (HC9800 (Netch Japan)). , Nitrogen gas having a water vapor partial pressure of 0.05 atm is flowed at 100 mL / min (22 ° C equivalent), and the temperature rises from 20 ° C at a rate of 1 ° C / min while applying a load of 98 mN to the upper and lower surfaces of the green compact. Then, the volume shrinkage was determined from the amount of height shrinkage of the green compact at 650 ° C. Shrinkage of the green compact represents combustion, decomposition and sintering of copper powder of the binder resin. The results are shown in Table 1.

[Specific resistance of sintered body]
Using the metal powder pastes and screen plates (stainless mesh, wire diameter 18 μm, gauze thickness 38 μm, opening 33 μm, aperture ratio 42%) of the examples and comparative examples obtained in the above procedure, a green sheet (manufactured by Yamamura Photonics Co., Ltd.) Three lines having a width of 5 mm and a length of 20 mm were printed on GCS71). While supplying the remaining nitrogen gas having a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at 2 L / min, the temperature was raised to 850 ° C. at a rate of 0.75 ° C./min and maintained at 850 ° C. for 20 minutes. Then, it was cooled to room temperature at a rate of 5 ° C./min in a pure nitrogen atmosphere containing no water vapor. In this way, a sintered body of the metal powder paste was formed on the ceramic substrate to obtain a sintered body / ceramic laminate. The surface resistivity and thickness of the circuit having a width of 5 mm and a length of 20 mm obtained by cooling to room temperature were measured, and the specific resistance was calculated by averaging three points. The results are shown in Table 1.

[Tape peeling test]
After attaching carbon double-sided tape (manufactured by Nissin EM) to the circuit and substrate obtained in the above test, the tape peeling test was performed in accordance with JIS Z 0237: 2009 at a peeling angle of 90 ° and a peeling speed of 5 mm / s. It was confirmed that the circuit did not adhere to the adhesive surface of the tape. When at least a part of the circuit (sintered body) was peeled off from the substrate in one peeling test, it was judged as ×, when it was peeled off in two or three times, it was judged as Δ, and when it was peeled off in four or more times, it was judged as ○. The results are shown in Table 1.

[Discussion]
When the metal powder pastes of Examples 1 to 14 in which the metal concentration derived from the coupling agent, the surface roughness (Ra) of the coating film, and the volume resistivity at the time of firing were appropriate were used, the firing was performed in a steam atmosphere. A conductor-ceramic laminate having a small specific resistance of the conductor and excellent adhesion between the conductors was obtained.
On the other hand, in Comparative Example 1, since the concentration of the metal derived from the coupling agent was too low, the sintering delay property was insufficient, and the adhesion between the ceramic and the conductor was insufficient.
In Comparative Example 2, since the concentration of the metal derived from the coupling agent was too high, the coupling agent gelled and the dispersibility of the surface-treated metal powder decreased, so that the surface roughness of the coating film became large and the specific resistance. As the temperature increased, the adhesion between the ceramic and the conductor became insufficient.
In Comparative Example 3, the concentration of the metal derived from the coupling agent was appropriate, but the pH at the time of pretreating the coupling agent was too low, so that the self-condensation reaction of the coupling agent did not proceed and the sintering was delayed. The properties were insufficient, and the adhesion between the ceramic and the conductor was insufficient.
In Comparative Example 4, the concentration of the metal derived from the coupling agent was appropriate, but the pH at the time of pretreating the coupling agent was too high, so that the self-condensation reaction of the coupling agent proceeded too much. For this reason, the coupling agent gels and the dispersibility of the surface-treated metal powder is lowered, so that the surface roughness of the coating film is increased and the adhesion between the ceramic and the conductor is insufficient.
In Comparative Example 5, the concentration of the metal derived from the coupling agent was appropriate, but the concentration of the coupling agent during the pretreatment was too low, so that the self-condensation reaction of the coupling agent did not proceed and the sintering delay property was increased. It became insufficient, and the adhesion between the ceramic and the conductor was insufficient.
In Comparative Example 6, the concentration of the metal derived from the coupling agent was appropriate, but the concentration of the coupling agent during the pretreatment was too high, so that the self-condensation reaction of the coupling agent proceeded too much. For this reason, the coupling agent gels and the dispersibility of the surface-treated metal powder is lowered, so that the surface roughness of the coating film is increased and the adhesion between the ceramic and the conductor is insufficient.
In Comparative Example 7, the concentration of the metal derived from the coupling agent was appropriate, but the pH at the time of pretreating the coupling agent was too low, so that the self-condensation reaction of the coupling agent did not proceed and the sintering was delayed. The properties were insufficient, and the adhesion between the ceramic and the conductor was insufficient.

Claims (9)

A conductive composition containing a metal powder, a binder resin, and a dispersion medium.
The metal powder, Si, have a surface treatment layer with a coupling agent containing one or more elements selected from the group consisting of T i 及 beauty Zr,
A sintered body obtained by heating the conductive composition to 850 ° C. with a residual nitrogen atmosphere of a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at a heating rate of 1 ° C./min and firing at 850 ° C. for 30 minutes. the Si as measured by ICP emission spectroscopy, the total concentration of T i及 beauty Zr a 1,000 to 10,000 mass ppm,
The conductive composition is applied onto a slide glass at a moving speed of 5 cm / sec using an applicator with a 25 μm gap, dried at 120 ° C. for 10 minutes, and then coated with a stylus type roughness meter. Arithmetic mean roughness Ra in the direction is 0.2 μm or less,
From 0.5 g of the powder obtained by crushing the coating film, a columnar green compact having a density of 4.7 ± 0.2 gcm ^-3 and a diameter of 5 mm was formed, and a load of 98 mN was applied to the green compact. Conductivity with a volume shrinkage of 15% or less at 650 ° C. when TMA measured at a heating rate of 1 ° C./min in a residual nitrogen atmosphere with a total pressure of 1 atm and a partial pressure of water vapor of 0.05 atm while being applied to the upper and lower surfaces. Composition. A sintered body obtained by heating the conductive composition to a total pressure of 1 atm, a steam partial pressure of 0.03 atm, a residual nitrogen atmosphere, a rate of 0.75 ° C./min to 850 ° C., and firing at 850 ° C. for 20 minutes. The conductive composition according to claim 1, wherein the specific resistance of the above is 3.0 μΩ · cm or less. The coupling agent, conductive composition according to claim 1 or 2 terminal is the coupling agent is an amino group. The conductive composition according to claim 3, wherein the coupling agent contains at least one of monoaminosilane and diaminosilane. The conductive composition according to any one of claims 1 to 4, wherein the metal powder contains copper powder. A sintered body obtained by heating the conductive composition to 850 ° C. with a residual nitrogen atmosphere of a total pressure of 1 atm and a water vapor partial pressure of 0.03 atm at a heating rate of 1 ° C./min and firing at 850 ° C. for 30 minutes. The conductive composition according to any one of claims 1 to 5, wherein the concentration of Si when measured by ICP emission spectroscopic analysis is 1000 to 10000 mass ppm. A method for producing a composite of a ceramic and a conductor using the conductive composition according to any one of claims 1 to 6. A method for producing a monolithic ceramic capacitor using the conductive composition according to any one of claims 1 to 6. A method for producing a ceramic circuit board using the conductive composition according to any one of claims 1 to 6.

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