JP2017171984A - Reactant, conductive composition, and method for producing surface-treated copper powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress the formation of copper oxide due to oxygen and humidity in each process of handling a conductive composition such as coating, drying and firing, which contains copper powder, and has excellent initial conductivity for a long period of time. Provided are a reactant capable of maintaining excellent conductivity, that is, a surface-treated copper powder, and a method for producing the same. A reaction product of a copper powder coated with a compound (A) represented by the formula (1) and a titanate-based coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule. Equation (1) (R1 to R4 are independently H or carboxyl groups; however, one or more of R1 to R4 are carboxyl groups) [Selection diagram] None

Description

  The present invention relates to a conductive material having excellent conductivity and reliability.

In the field of printed electronics, conductive compositions in which metal powder is dispersed are used for applications such as formation of printed circuits and electromagnetic wave shields that make use of the coating processability and conductivity. Such a conductive composition is usually considered to exhibit conductivity through a heating process, through the curing shrinkage of the film, the contact of the metal powder due to the volatilization of organic matter, and the fusion of the metal powder.

Conventionally, silver powder having excellent stability and conductivity in the atmosphere has been used as the metal powder used in the conductive composition. However, the use of silver powder is problematic because it is a noble metal, is expensive, has a large fluctuation in market price, and is short-circuited due to migration during energization under high temperature and high humidity.

In overcoming the problems of these silver powders, there is a great expectation for conductive compositions using copper powder which is inexpensive but is expected to have almost the same conductivity as silver. However,
Essentially, copper has a problem that it is easily oxidized by oxygen and humidity as compared with silver, and easily changes to copper oxide having poor conductivity. In particular, humidity is presumed to be the largest factor that promotes the deterioration of copper powder.

Such oxidation of copper powder can be performed by storing it in a copper powder state, preparing a composition containing copper powder, applying the composition, drying and firing the applied product, Since the process proceeds in every process such as use, it is very difficult to ensure the original conductivity of copper at an early stage and to maintain the conductivity for a long period of time to ensure the reliability of the product.

As a study to prevent such oxidation of copper powder, a method is proposed in which the surface of copper powder is treated with a rust inhibitor or a coupling agent, and as a result, the surface of copper is coated or modified. Has been.

For example, as a method for coating the surface of copper powder with a rust inhibitor, copper powder having a rust preventive film typified by benzotriazole is disclosed (Patent Document 1). In addition, as a method of treating the surface of copper powder with a coupling agent, a method of coating with an organic titanate to make lipophilic and a method of treating with an aqueous solution of a coupling agent having an amino group are disclosed (patents). Literature 2, 3).

Furthermore, the processing method and usage method of copper and copper powder which used said antirust agent and coupling agent together are also disclosed. As such a method, a method is disclosed in which a metal whose surface is treated with a titanate coupling agent is used in water containing a benzotriazole agent (Patent Document 4).
A copper surface treatment agent containing an azolesilane compound and benzotriazole is also disclosed (Patent Document 5).

However, the method of simply coating the copper powder with a known rust preventive agent represented by benzotriazole is insufficient in effect to overcome the susceptibility to oxidation of copper, so that the oxidation proceeds reliably,
The conductivity of the copper powder or the composition using the copper powder will be significantly reduced.

In addition, the method of treating the copper powder surface with organic titanate has the effect of making the copper powder surface oleophilic and can isolate the copper powder to some extent from humidity, which is one of the deterioration factors. It is. However, even with this method, it is difficult to suppress the oxidation for a long period of time and use the copper powder as a conductive material having sufficient reliability, and there is a method for making the surface of the copper powder more lipophilic. It was necessary.

On the other hand, the method of treating copper powder with an aqueous solution of a coupling agent having an amino group is effective in coating copper powder, but is a hydrophilic treatment material, so the surface of copper powder is modified to be lipophilic. There was no effect, and the effect of protecting copper powder from humidity, which was a deterioration factor, was poor.

The method of using metal treated with titanate coupling agent in water with benzotriazole agent added is not only difficult to develop into copper powder for use in conductive compositions, but also inhibits copper oxidation It was insufficient as a method to do.

Although the copper surface treatment agent containing an azolesilane compound and benzotriazole is recognized to have an effect of preventing discoloration of the copper powder, to use the copper powder as a reliable conductive material,
Antioxidation effect was insufficient. In particular, the antioxidant effect on humidity was poor. This is presumably because the material in the range disclosed in Patent Document 5 is insufficient in covering and oleophilicizing the copper powder surface.

JP-A-4-308605 JP 59-174661 A JP2015-36442 A JP-A-62-20883 International Publication No. 2011/043236 Pamphlet

The present invention effectively suppresses the formation of copper oxide due to oxygen and humidity in each process in which conductive compositions such as storage, coating, drying, and firing are handled, and not only has excellent initial conductivity, but also long-term use. An object of the present invention is to provide a surface-treated copper powder capable of maintaining excellent conductivity and a method for producing the same. Furthermore, it aims at providing the electroconductive composition which uses this copper powder.

As a result of intensive studies to solve the above problems in consideration of the above problems, the present inventors have reached the present invention. That is, the present invention provides a copper powder coated with the compound (A) represented by the general formula (1) and a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule. Reactant related.

General formula (1)

(Wherein R1 to R4 represent a hydrogen atom or a carboxyl group, provided that R1 to R4
At least one of 4 is a carboxyl group. )

Furthermore, this invention relates to the said reaction material in which the titanate coupling agent (B) which has at least 1 C8 or more alkyl group in a molecule | numerator is represented by following General formula (2).

General formula (2)

(In the formula, n and m each independently represent a natural number, and n + m = 4 or 6.
R11 represents an alkoxy group having 1 to 8 carbon atoms when n = 1, and represents an alkoxy group having 1 to 8 carbon atoms when n is 2 or more, or R11 has two R11 and the following general formula The group represented by (3) or the group represented by the following general formula (4).
R12 represents a substituent selected from the following general formula (5) to the following general formula (9). )

General formula (3)

(Wherein R13 represents an alkylene group having 2 to 16 carbon atoms).

General formula (4)

(In the formula, R14 represents an alkylene group having 1 to 15 carbon atoms.)

General formula (5)

(In the formula, R21 represents an alkyl group having 8 to 30 carbon atoms.)

General formula (6)

(In the formula, R 31 and R 32 each independently represents an alkyl group having 8 to 30 carbon atoms.)

General formula (7)

(Wherein R41 and R42 each independently represents an alkyl group having 8 to 30 carbon atoms)

General formula (8)

(In the formula, R51 and R52 each independently represents an alkyl group having 8 to 30 carbon atoms.)

General formula (9)

(In the formula, R61 represents an alkyl group having 8 to 30 carbon atoms.)

Furthermore, this invention relates to the said reaction material whose substituent R12 in General formula (2) is General formula (8).

Furthermore, this invention relates to the electroconductive composition containing the said reaction material and a thermosetting resin (C).

In the present invention, the copper powder (D) is treated with a solution containing the compound (A) represented by the following general formula (1), and then at least one alkyl group having 8 or more carbon atoms is further added to the molecule. It is related with the manufacturing method of the surface treatment copper powder processed with the titanate coupling agent (B) which has.

General formula (1)

(Wherein R1 to R4 represent a hydrogen atom or a carboxyl group, provided that R1 to R4
At least one of 4 is a carboxyl group. )

In the present invention, the surface of the copper powder can be easily coated, and the surface of the copper powder is coated with the compound (A) capable of enriching the surface of the copper powder with a carboxyl group that becomes a reaction point with the titanate coupling agent. Forming a remarkably lipophilic film on the surface of the copper powder by reacting the copper powder with a titanate coupling agent (B) having an alkyl group having 8 or more carbon atoms for imparting lipophilicity. Is possible. This coating is not only difficult to become a resistance component even when present on the surface of the copper powder, but can sufficiently isolate the copper powder from oxygen and humidity that cause oxidation. as a result,
In addition to excellent initial conductivity, it is possible to obtain a copper powder capable of maintaining excellent conductivity over a long period of time, and further a conductive composition using the copper powder.

It is an evaluation sample for evaluating the conductivity of a conductive composition in the form of a film. It is a connection point when evaluating the conductivity of the evaluation sample.

The present invention provides a reaction between a copper powder coated with the compound (A) represented by the general formula (1) and a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule. It is a thing.
General formula (1)
(Wherein R1 to R4 represent a hydrogen atom or a carboxyl group, provided that R1 to R4
At least one of 4 is a carboxyl group. )

As described in the background art section, the method of making the surface of the copper powder oleophilic by the coupling agent and isolating it from the humidity, which is the biggest factor that oxidizes the copper powder, is a method for maintaining the conductivity of the copper powder. Is considered a promising technique. However, when the surface modification by the reaction between the copper powder and the coupling agent is considered in detail, the following problems exist.

Since copper is easily oxidized, it is generally considered that a copper oxide (CuO, Cu2O) film is present on the surface of the copper powder. On the other hand, when considering the surface treatment of particles with a coupling agent, the reaction point is considered to be a nucleophilic substituent such as a hydroxyl group, amino group, or carboxyl group present on the particle surface.

When considering the treatment of common copper powder with a coupling agent, the metal copper itself and the copper oxide film existing on the surface are unlikely to be reactive sites, and are present on the surface of the copper powder mixed with copper oxide. A hydroxyl group (for example, Cu-OH state) is considered to be the reaction site. The hydroxyl groups present in the copper oxide film are accidentally generated, and it is difficult to control the amount, and there is no surely enough amount to modify with the coupling agent. .

In the present invention, copper powder whose surface is previously coated with the compound (A) represented by the general formula (1) is used. The compound (A) has a benzotriazole skeleton and at least one carboxyl group in the molecule. The benzotriazole skeleton is one of known anticorrosive agents that have been known for a long time, and has a feature of easily adsorbing on the surface of copper powder to form a film. The form of the coating is also considered to be a two-dimensional network of copper or copper ions and a benzotriazole skeleton.

As will be described in detail in the Examples section, it has been found that the compound (A) is also very easily adsorbed to the copper powder to form a film. Since the compound (A) also has a carboxylic acid in the molecule, the copper powder coated with the compound (A) can intentionally have a significant number of carboxyl groups on its surface.

This remarkably large number of carboxyl groups can be a reaction point with the coupling agent as described above. Therefore, the reaction product of the copper powder coated with the compound (A) represented by the general formula (1) and the titanate coupling agent (B) is compared with the reaction product of the coupling agent with the mere copper powder. The degree of modification of the copper powder surface by the coupling agent is remarkably increased.

Here, as a titanate coupling agent (B), at least 1 which can provide lipophilicity
By selecting a titanate coupling agent having two alkyl groups having 8 or more carbon atoms, the surface of the copper powder can be remarkably hydrophobized. As a result, it becomes difficult for the humidity, which is the largest oxidation factor, to be in direct contact with the copper powder, the deterioration of the copper powder is suppressed, and high conductivity can be maintained over a long period of time.

The present invention provides a reaction between a copper powder coated with the compound (A) represented by the general formula (1) and a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule. Although there is a coating on the surface of the obtained copper powder to suppress deterioration, this coating does not significantly inhibit the conductivity of the copper powder and is excellent in initial conductivity. Yes. At present, the reason for this is not clear, but it is considered that the two-dimensional network that is considered to be formed of the compound (A) and copper or copper ions is superior in conductivity to a normal organic substance. Moreover, since the copper powder which is the reaction product of the present invention hardly generates an oxide film as a resistance component, as a result,
It is also a material with excellent initial conductivity.

In the application of this application, the chemical structure and detailed composition of the coating on the surface of the reactant of the present invention, that is, the surface-treated copper powder should be specified. However, the film obtained by the reaction with the coupling agent does not necessarily have a single chemical structure, and further, detailed composition analysis in the ultrathin film on the surface of the copper powder is necessary. It is difficult to identify.

For detailed composition analysis of the copper powder surface, it is necessary to carry out analysis using a large number of samples using an X-ray photoelectron spectrometer. For those who do not have this equipment, the time and economy required for requested analysis This is currently not possible due to the significant burden on the company.

However, based on the above-mentioned idea, a reaction product that has been reliably and highly inhibited from degradation, that is, a surface-treated copper powder, can be reliably produced, and further, an optimum production method for obtaining it can be obtained. Since it has been specified, the present invention is filed as a reactant.

  The compound (A) will be described in detail.

The compound (A) used in the present invention is represented by the general formula (1) and is characterized by having at least one carboxyl group on the benzene ring in the benzotriazole skeleton. As described above, the benzotriazole skeleton serves as an adsorption site on the surface of the copper powder and forms a film on the surface of the copper powder, and the carboxyl group is bonded to the titanate coupling agent (B) on the surface of the copper powder. Responsible for forming reaction points. Therefore, as shown by the general formula (1), any material having a benzotriazole skeleton and at least one carboxyl group in the molecule can be expected to have the same effect.

  R1 to R4 in the general formula (1) will be described.

R1 to R4 each represents a hydrogen atom or a carboxyl group, and at least one of R1 to R4 represents a carboxyl group.

Specific examples of the compound represented by the general formula (1) include 4-carboxybenzotriazole, 5-carboxybenzotriazole, 6-carboxybenzotriazole, 7-carboxybenzotriazole, 5,6-dicarboxybenzotriazole and the like. be able to. These are known compounds and are available as reagents from Tokyo Chemical Industry Co., Ltd., Sigma Aldrich Japan Co., Ltd. and the like.

Among the above-mentioned benzotriazoles having a carboxy group, it is preferable that only one of R1 to R4 is a carboxyl group in terms of high solubility and easy preparation of a solution for treating copper powder.

In the present invention, the copper powder may be coated with one or more compounds (A).

When the copper powder is coated with the compound (A), the crystal or powder of the compound (A) is dissolved in a solvent to be described later, and the copper powder is immersed and processed. The crystal or powder of the compound (A) used here is 2
It may be a crystal of a mixture of two or more kinds of compounds (A). Furthermore, you may have hydration water in a crystal | crystallization. Examples of such materials include benzotriazole compound CBT-1 manufactured by Johoku Chemical Industry Co., Ltd. This material is a crystal of a hydrate of a mixture of two kinds of monosubstituted carboxybenzotriazoles, and can be particularly preferably used as the compound (A) used in the present invention.

Next, a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule will be described.

The titanate coupling agent in the present invention is a reactive surface modification in which both a hydrolyzable substituent represented by an alkoxy group and a residue of an organic acid are bonded to Ti as a central element. Means an agent. Reacts easily with nucleophilic substituents present on the particle surface, resulting in the removal of hydrolyzable substituents and the lipophilicity of the particle surface by the residues of organic acids remaining in the state of binding to Ti. It is a material that can change dispersibility.

In the present invention, the titanate coupling agent (B) reacts with some or all of the carboxyl groups present on the surface of the copper powder coated with the compound (A) to impart significant lipophilicity to the copper powder surface. Used in. Accordingly, in the molecule of the titanate coupling agent, at least one alkyl group having 8 or more carbon atoms is indispensable as a hydrophobic group that is sufficiently oleophilic on the surface of the copper powder. If there is only an alkyl group having 7 or less carbon atoms in the molecule of the titanate coupling agent, the surface of the copper powder cannot be sufficiently oleophilic, and oxidation of the copper powder proceeds due to humidity.

The titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule used in the present invention is preferably represented by the general formula (2).

General formula (2)

(In the formula, n and m each independently represent a natural number, and n + m = 4 or 6.
R11 represents an alkoxy group having 1 to 8 carbon atoms when n = 1, and represents an alkoxy group having 1 to 8 carbon atoms when n is 2 or more, or R11 has two R11 and the following general formula The group represented by (3) or the group represented by the following general formula (4).
R12 represents a substituent selected from the following general formula (5) to the following general formula (9). )

General formula (3)

(Wherein R13 represents an alkylene group having 2 to 16 carbon atoms).

General formula (4)

(In the formula, R14 represents an alkylene group having 1 to 15 carbon atoms.)

General formula (5)

(In the formula, R21 represents an alkyl group having 8 to 30 carbon atoms.)

General formula (6)

(In the formula, R 31 and R 32 each independently represents an alkyl group having 8 to 30 carbon atoms.)

General formula (7)

(Wherein R41 and R42 each independently represents an alkyl group having 8 to 30 carbon atoms)

General formula (8)

(In the formula, R51 and R52 each independently represents an alkyl group having 8 to 30 carbon atoms.)

General formula (9)

(In the formula, R61 represents an alkyl group having 8 to 30 carbon atoms.)

  The general formula (2) will be described in detail.

  N and m in the general formula (2) will be described.

n and m each independently represent a natural number, and in general formula (2), n represents the number of substituents of R11, and m represents the number of substituents of R12. The sum of n and m is the number of bonds that a titanium atom can form, and is 4 or 6.

R11 in the general formula (2) can be eliminated by reacting with the carboxylic acid present on the surface of the copper powder coated with the compound (A), while R12 is bonded to Ti as a relatively stable substituent. Yes.
Therefore, as a result of the reaction between the copper powder coated with the compound (A) and the titanate coupling agent represented by the general formula (2), a large number of R12 is present on the surface of the copper powder via a COO-Ti bond. As a result, a surface-treated copper powder is obtained. From this mechanism, it is considered that R11 has a relatively small influence on the physical properties of the reaction product of the present invention, that is, the surface-treated copper powder, and may be appropriately selected from the viewpoints of easy availability and manufacturing cost.

  The substituent in General formula (2) is demonstrated.

R11 represents an alkoxy group having 1 to 8 carbon atoms. As an alkoxy group here,
Examples thereof include linear, branched, and monocyclic alkyloxy groups having 1 to 8 carbon atoms. Specifically, for example, methyloxy group, ethyloxy group, propyloxy group, butyloxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, isopropyloxy group, isobutyloxy group, isopentyloxy group, sec-butyloxy group, te
rt-butyloxy group, sec-pentyloxy group, tert-pentyloxy group, te
rt-octyloxy group, neopentyloxy group, cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group and the like can be mentioned.

  The general formula (3) will be described.

R13 in the general formula (3) represents an alkylene group having 2 to 16 carbon atoms. Examples of the alkylene group herein include straight chain, branched chain, and cyclic alkylene groups having 2 to 16 carbon atoms. Specifically, for example, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-
Decylene group, n-dodecylene group, n-hexadecylene group, isopropylene group, isobutylene group, isopentylene group, cyclopentylene group, cyclohexylene group, bicyclo [2.2
. 1] A heptane-2,6-diyl group and the like can be mentioned, but are not limited thereto.

  The general formula (4) will be described.

R14 in the general formula (4) represents an alkylene group having 1 to 15 carbon atoms. Examples of the alkylene group herein include straight-chain, branched-chain, and cyclic alkylene groups having 1 to 15 carbon atoms. Specifically, for example, methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n -Decylene group, n-dodecylene group, n-pentadecylene group, isopropylene group, isobutylene group, isopentylene group, cyclopentylene group, cyclohexylene group, bicyclo [2.2.1] heptane-2,6-diyl group, etc. However, it is not limited to these.

  R12 in the general formula (2) will be described.

R12 is a residue of an organic acid and represents a substituent selected from the general formula (5) to the general formula (9).

R21 in the general formula (5), R31 and R32 in the general formula (6), the general formula (7
) R41 and R42 in general paper (8), R51 and R52 in general paper (8), general formula (9)
) Each independently represents an alkyl group having 8 to 30 carbon atoms. Examples of the alkyl group herein include straight chain, branched chain, and cyclic alkyl groups having 8 to 30 carbon atoms. Specifically, for example, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, docosyl group, hexacosyl group, triacontyl group, isooctyl group, isoheptadecyl group, tert-octyl group , Adamantyl group, norbornyl group, 4-decylcyclohexyl group and the like, but are not limited thereto.

Among these alkyl groups, R21 in the general formula (5), R3 in the general formula (6)
1 and R32, R41 and R42 in general formula (7), R5 in general paper (8)
1 and R52, and R61 in the general formula (9) are those having a carbon number of 8 to 18 in terms of compatibility when preparing a solution for treating copper powder and industrially easily available. It is particularly preferred.

Among these titanate coupling agents (B), when R12 is a material represented by the general formula (8), the reaction product obtained by the present invention, that is, the surface-treated copper powder, is particularly excellent in acid resistance. It is most preferable because it can impart a chemical property.

At present, the reason for this is not completely clear, but O bonded to the phosphorus atom in the general formula (8).
It is presumed that the H group strongly forms a stronger hydrophobic film by strongly interacting with the copper powder or the film made of the compound (A) formed on the surface thereof.

As a specific example of the titanate coupling agent (B) represented by the general formula (2) and having at least one alkyl group having 8 or more carbon atoms,
Isopropyl triisostearoyl titanate, isopropyl tristearoyl titanate, isopropyl tricaproyl titanate, isopropyl trilauroyl titanate,
Isopropyl tripalmitoyl titanate, diisopropyl diisostearoyl titanate, diisopropyl dilauroyl titanate, diisopropyl dipalmitoyl titanate, triisopropoxy titanium octanoate,
Tetraoctyl bis (ditridecyl phosphite) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraisopropyl bis (distearyl phosphite) titanate, tetraisopropyl bis (dilauryl phosphite) titanate,
Isopropyltris (dioctyl pyrophosphate) titanate, isopropyl tris (dilauryl pyrophosphate) titanate, isopropyl tris (dimyristyl pyrophosphate) titanate, isopropyl tris (distearyl pyrophosphate)
Titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, diisopropylbis (dioctylpyrophosphate) titanate, diisopropylbis (distearylpyrophosphate) titanate, octyltris (dioctylpyrophosphate) titanate, dioctyl Bis (dioctylpyrophosphate) titanate,
Bis (dioctyl phosphate) ethylene titanate, isopropyl tris (dioctyl phosphate) titanate, isopropyl tris (distearyl phosphate) titanate, butyl tris (dioctyl phosphate) titanate, tris (dioctyl phosphate)
Octyloxytitanium,
Examples thereof include isopropyl tris (dodecylbenzenesulfonyl) titanate and diisopropylbis (dodecylbenzenesulfonyl) titanate.

The titanate coupling agents exemplified above are available as product names “Plenact” (registered trademark) series manufactured by Ajinomoto Fine Techno Co., Ltd., and the model numbers are Plenact TTS, Plenact 46B, Plenact 41B, Plenact 38S. , Plenact 138S, Plenact 238S, Plenact 338X, Plenact 9S
A etc. can be mentioned.

  Next, the manufacturing method of the surface treatment copper powder of this invention is demonstrated in detail.

The manufacturing method of the surface-treated copper powder of this invention processes the copper powder (D) with the solution containing a compound (A), and coat | covers it (process 1), and the compound (A) obtained by a 1st process. The copper powder coated with (2) is treated with a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule to obtain a reaction product (step 2).

  Step 1 will be described in detail.

“Treatment” in the process of treating copper powder (D) with a solution containing compound (A) means mixing copper powder (D) and a solution containing compound (A) and going through a slurry state. means.
In this slurry, the coating of the copper powder (D) with the compound (A) proceeds even when left standing, and when it is desired to proceed the coating more uniformly, the slurry is stirred or shaken as necessary. May be mixed. For such stirring and shaking, any known stirring method, mixing method, and dispersion method can be used. Further, with this stirring, mixing, and dispersion, the copper powder (D) may be coated with the compound (A), and at the same time, may be deformed.

  The copper powder (D) will be described.

The excellent initial conductivity and oxidation resistance of the conductive material according to the present invention are attributed to the film formed by the reaction product of the compound (A) and the titanate coupling agent (B), which is finally formed on the surface of the copper powder. Therefore, the shape and particle size of the copper powder (D) are not particularly limited, and any shape of copper powder can be used as long as it can obtain conductivity corresponding to a desired application such as a conductive paste or an electromagnetic shielding sheet. It is possible to use.

Specific examples of the shape of the copper powder (D) include, for example, a spherical shape, a flake shape, a leaf shape, a dendritic shape, a plate shape, a needle shape, and a grape shape. Among these, a dendritic shape, a leaf shape, or a flake shape in which contact between copper powders is good and high conductivity is obtained is more preferable. Moreover, the copper powder (D) may be a mixture of two or more types of copper powders having different particle sizes and shapes. Such copper powder is easily available from a manufacturer that handles metal powder. Further, a physical force may be applied to the above-described copper powder to further deform the shape.

Commercially available copper powder may already have a copper oxide film or a rust preventive agent for storage on its surface, but in the present invention, commercially available copper powder may be used as it is as copper powder (D). And after removing said copper oxide film and a rust preventive agent, you may use as copper powder (D).

Any known method may be used as a method for removing the copper oxide film and the rust inhibitor from the copper surface. One example of such a method is acid washing of copper powder using organic acids such as formic acid, acetic acid and fatty acids, and inorganic acids such as sulfuric acid and hydrochloric acid. After washing, rinsing with water or an organic solvent may be performed so that no acid remains, and the acid may be dried. It is particularly preferable to use copper powder that has been acid-washed in advance as the copper powder (D), since the initial conductivity is improved and the copper powder coated with the compound (A) is easily obtained.

The specific particle diameter of the copper powder (D) is preferably an average particle diameter of 0.5 to 100 μm,
50 μm is more preferable. If it exists in this range, also when using as a conductive composition also including a thermosetting resin (C), since the below-mentioned coating and printing suitability are favorable, it is preferable. The average particle diameter here is a D50 average particle diameter obtained by measuring copper powder with a tornado dry powder sample module using a laser diffraction / scattering particle size distribution measuring device LS13320 (manufactured by Beckman Coulter, Inc.). And the average particle diameter of the diameters of the particles having an integrated value of 50%. This measurement was performed with the refractive index of the particles set to 1.6.

  The solution containing the compound (A) will be described.

The solution containing the compound (A) can be obtained by dissolving crystals or powder containing the compound (A) in a solvent. As described above, the crystal or powder containing the compound (A) used here may be a crystal of a mixture of two or more kinds of compounds (A), and has water of hydration in the crystal. It may be. Examples of such materials include benzotriazole compound CBT-1 manufactured by Johoku Chemical Industry Co., Ltd. This material is a crystal of a hydrate of a mixture of two kinds of monosubstituted carboxybenzotriazoles, and can be particularly preferably used as the compound (A) used in the present invention.

Since the compound (A) is a material that actively adsorbs on the surface of the copper powder in the molecular state to form a film, the solvent used when preparing the solution dissolves the compound (A) uniformly. Any solvent may be used as long as it is liquid. However, since the compound (A) has a carboxyl group, a solvent having a relatively high polarity and a high dielectric constant can be particularly preferably used. Examples of such solvents include water, alcohol solvents, ester solvents, ketone solvents,
Examples thereof include nitrile solvents and amide solvents. More specifically, the alcohol solvent is methanol, ethanol, propanol, isopropanol, n-butanol, etc., and the ester solvent is ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, And dimethyl carbonate, etc.
Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, diisobutyl ketone, diacetone alcohol, isophorone, and cyclohexanone. Examples of nitrile solvents include acetonitrile, propionitrile, and 3-methoxypropionitrile. Examples of the solvent include, but are not limited to, N, N-dimethylformamide, N-methylpyrrolidinone and the like. Furthermore, you may use these in mixture of 2 or more types.

As will be described later, when the surface-treated copper powder is simply manufactured by carrying out Step 1 and Step 2 in one pot, since the titanate coupling agent (B) used in Step 2 has hydrolyzability, other than water It is preferable to select a solvent.

The amount of compound (A) in the solution containing compound (A) is not particularly limited, but 0.001 part by weight or more and 2 parts by weight or less are dissolved in a solvent with respect to 100 parts by weight of copper powder (D) to be treated. And preferably used in an amount of 0.01 parts by weight or more and 1 part by weight or less. If the compound (A) is less than this range, the copper powder (D) cannot be sufficiently covered with the compound (A), so that the oxidation resistance of the surface-treated copper powder is lowered. When a compound (A) exceeds this range, since the film which exists on the copper powder surface is too thick, initial electrical conductivity may fall.

In this step, the compound (A) to be used may form a film on the copper powder with the total amount thereof, or may form a film with a part thereof. In the present invention, the compound (A) is used for the purpose of enriching the reaction point with the titanate coupling agent (B) on the surface of the copper powder. do not have to. That is, even if there is a compound (A) that remains in the solution without being adsorbed by the copper powder, there is no problem in the practice of the invention.

In addition, although described in detail in the Examples section, the compound (A) used in an amount within the range described above is
It is confirmed that about 50% of the total amount of the compound (A) used is adsorbed on the surface of the copper powder (D) and forms a film with respect to 100 parts by weight of the copper powder. If it is this adsorption rate, it is thought that the film of a compound (A) sufficient for implementing this invention has formed in the copper powder surface.

The concentration of the compound (A) in the solution containing the compound (A) for treating the copper powder (D) is not particularly limited, but when treating 100 parts by weight of the copper powder, the solvent is 50 parts by weight or more, 200
It is preferable to prepare a solution of the compound (A) by using in the range of 0 part by weight or less. If the amount of the solvent is less than this range, it is difficult to sufficiently immerse and process the copper powder (D),
If the amount of the solvent is larger than this range, a large container and equipment are required as compared with the obtained copper powder, and the production efficiency is lowered.

The temperature at the time of processing copper powder (D) with the solution containing a compound (A) is not specifically limited, What is necessary is just the temperature below the boiling point and above melting | fusing point in which the solvent mentioned above makes liquid state. However, if the temperature is too high, oxidation of the copper powder (D) may proceed during the treatment, and therefore, it is preferable to carry out at 90 ° C. or less. Further, since the phenomenon of coating the copper powder (D) with the compound (A) proceeds without particularly heating or cooling, it is most economical and simple to carry out at around normal room temperature.

The processing time when processing copper powder (D) with the solution containing the compound (A) is not particularly limited. In many cases, the coating of the copper powder (D) with the compound (A) proceeds sufficiently in about 30 to 120 minutes.

The atmosphere when treating the copper powder (D) with the solution containing the compound (A) may be in the air or an inert gas atmosphere such as nitrogen or argon. Further, it may be an atmosphere containing a reducing gas such as hydrogen or copper formate.

After processing copper powder (D) with the solution containing compound (A), a slurry in which copper powder coated with compound (A) is dispersed in a solvent is obtained. The slurry obtained here may proceed to the next step 2 or may proceed to step 2 after isolating the copper powder coated with the compound (A) as a powder. If the slurry is used as it is in step 2, it is more preferable because the production method of the present invention can be most easily carried out.

The method for isolating the copper powder coated with the compound (A) from the slurry obtained after completion of the step 1 is not particularly limited. For example, methods such as filtration through a filter paper, a filter cloth, and a glass filter, centrifugation, and dentation can be used. The copper powder isolated by these methods may be washed with an organic solvent or water as necessary, and may be used in step 2 after drying. As a drying method, any known drying method such as reduced pressure drying or hot air drying can be used.

  Step 2 will be described in detail.

In the step of treating the copper powder coated with the compound (A) with a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule to obtain a reaction product, “
“Treatment” means mixing the copper powder coated with the compound (A) with a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule in a dry or wet manner. means. Since the titanate coupling agent (B) is rich in reactivity, it reacts quickly with carboxyl groups present on the surface of the copper powder coated with the compound (A). By this mixing, the reaction product of the present invention, that is, the surface-treated copper powder is completed.

Specifically, the wet process 2 includes a titanate coupling agent having at least one alkyl group having 8 or more carbon atoms in the molecule in a slurry composed of a copper powder coated with the compound (A) and a solvent. This is a method of adding B).

Here, the slurry composed of the copper powder coated with the compound (A) and the solvent means that the slurry after the treatment of the copper powder (D) in Step 1 with the solution containing the compound (A) is filtered, washed, etc. You can use it for step 2 as it is,
The slurry may be prepared by isolating the copper powder from the slurry after the completion of Step 1 and, if necessary, washing and drying, and then mixing it with a solvent.

  The solvent for carrying out step 2 in a wet manner will be described.

Once the copper powder coated with the compound (A) is isolated after the completion of the step 1, the solvent used when preparing the slurry of the copper powder used in the step 2 is the coupling agent (B). If it melt | dissolves and it reacts with a coupling agent (B) and does not lose reactivity, it will not specifically limit. Examples of such solvents include hydrocarbons, aromatics, esters, ketones, alcohols, amides, and nitriles. Specifically, hexane, octane,
Cyclohexane, toluene, xylene, methanol, ethanol, propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, acetone, 2-butanone, cyclohexanone, acetonitrile,
Propionitrile, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidinone and the like can be mentioned, but are not limited thereto. Furthermore, you may use these in mixture of 2 or more types.

When the slurry obtained in step 1 is used as it is in step 2, the solvent is the same as the solvent used in step 1, but there is no problem. Furthermore, it is also possible to add the above-mentioned solvent to the slurry obtained in step 1 and use it.

When adding a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in a molecule to a slurry composed of a copper powder coated with the compound (A) and a solvent,
The coupling agent (B) may be added as it is, or may be added in the form of a solution diluted with a solvent, if necessary. As the solvent used in this case, it is possible to use the same solvents as those listed above in the section of the solvent used in Step 2.

The titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule used in the wet process 2 is a copper powder contained in the copper powder coated with the compound (A) ( D) It is preferably used in the range of 0.005 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight, and more preferably in the range of 0.05 parts by weight or more and 5 parts by weight or less. preferable. The titanate coupling agent is used for the purpose of making the copper powder surface sufficiently lipophilic starting from the carboxylic acid in the compound (A) present on the copper powder surface. It is difficult to improve the oxidation resistance of the powder. If this range is exceeded, a large amount of unreacted titanate coupling agent may remain in the copper powder,
When the conductive composition of the present invention is prepared, there is a possibility that an adverse effect may occur, which is not preferable.

In the wet process 2, the temperature at the time of the treatment is not particularly limited, and may be any temperature as long as the solvent described above is in a liquid state and below the boiling point and above the melting point. However, if the temperature is too high, oxidation of the copper powder may proceed during the treatment.
In addition, the reaction between the carboxylic acid present on the surface of the copper powder coated with the compound (A) and the coupling agent (B) proceeds sufficiently even without heating or cooling, so it is carried out at around normal room temperature. It is the most economical and simple to do.

In the wet process 2, the treatment time is not particularly limited. However, since the titanate coupling agent (B) is highly reactive, the titanate coupling agent (B ), A surface-treated copper powder can be obtained.

  Next, the dry process 2 will be described.

As a method of treating the copper powder coated with the compound (A) by a dry method and the titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule,
Copper powder coated with compound (A) isolated from the slurry after completion of step (1) and subjected to washing and drying as necessary, and at least one alkyl having 8 or more carbon atoms in the molecule A titanate coupling agent (B) having a group may be mixed and stirred in a known apparatus such as a powder mixer or a pulverizer. Examples of such an apparatus include, but are not limited to, a Laedige mixer, a Henschel mixer, and a V-type mixer. Further, the temperature and time for the treatment are not particularly limited.

When carrying out the above-mentioned dry mixing process, the titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule is added alone to the copper powder coated with the compound (A). Alternatively, it may be diluted with a solvent as necessary. Moreover, as the addition method, although the method of dripping or spraying with respect to the copper powder coat | covered with the compound (A) is mentioned, it is not limited to these.

The titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule when carrying out the dry process 2 is the same as the amount described in the wet process (2). A range is preferred.

As described above, the wet and dry copper powder coated with the compound (A) is at least 1 in the molecule.
Although the method of treating with a titanate coupling agent (B) having two alkyl groups having 8 or more carbon atoms has been described, a wet treatment is more preferred. The reason is that the step (1) and the step (2) can be carried out in one pot, and the production method of the present invention can be carried out most uniformly and simply.

In addition, after completion | finish of the process 2 by wet, the slurry which contains the reaction material of this invention, ie, surface-treated copper powder, and a solvent, ie, the dispersion of copper powder, is obtained. When preparing the conductive composition of the present invention, this dispersion may be used as it is for the preparation of the conductive composition, and if necessary, the reactant present in the dispersion, that is, surface-treated copper. The powder may be used after being isolated.

The method for isolating the reaction product of the present invention, that is, the surface-treated copper powder, from the slurry obtained in the wet step 2 is not particularly limited. For example, methods such as filtration through filter paper, filter cloth, and glass filter, centrifugation, and decantation can be used. The copper powder isolated by these methods may be washed with an organic solvent or water, if necessary, and after drying, the step (2
). As a drying method, any known drying method such as reduced pressure drying or hot air drying can be used. As a drying temperature, the range of 0 degreeC or more and 90 degrees C or less is preferable.

  Next, the conductive composition containing the reaction product of the present invention and the thermosetting resin (C) will be described.

  The thermosetting resin (C) will be described.

You may use the reaction material obtained by this invention, ie, surface-treated copper powder, as an electroconductive composition containing a thermosetting resin (C) further. When the conductive composition of the present invention containing the thermosetting resin (C) forms a conductive film that can be used for electromagnetic wave shielding or the like by coating, when forming a conductive circuit such as an antenna for RFID by printing, Furthermore, it can be used particularly suitably for various applications such as when used as a conductive filler for vias for interlayer connection of multilayer printed wiring boards.

The thermosetting resin (C) in the present invention has a crosslinkable functional group that reacts with a curing agent. Examples of the crosslinkable functional group include a hydroxyl group, a phenolic hydroxyl group, a carboxyl group, an epoxy group, an oxazoline group, an oxazine group, a silanol group, an alkoxysilane group, a hydroxyl group, an amino group, an imino group, an isocyanate group, and a blocked isocyanate group. Blocked carboxyl group, aziridine group, thiol group, cyclocarbonate group, vinyl ether group, vinyl thioether group, aminomethylol group, alkylated aminomethylol group,
Examples include an acetal group and a ketal group. These thermosetting resins can have two or more types of crosslinkable functional groups.

As the above-mentioned thermosetting resin, for example, polyester resin, epoxy ester resin,
Examples thereof include, but are not limited to, polyamide resins, polyurethane resins, phenoxy resins, phenol resins, and polyacryl resins.

The thermosetting resin (C) may accelerate curing using a curing agent. Such a hardening | curing agent should just be a compound which has one or more functional groups which can react with the crosslinkable functional group of a thermosetting resin, and is not specifically limited. For example, when the crosslinkable functional group is a carboxyl group, the curing agent is preferably an epoxy compound, an alidiline compound, an isocyanate compound, a polyol compound, an amine compound, a melamine compound, a silane type, a carbodiimide type compound, a metal chelate compound, etc. When the functional group is a hydroxyl group, the curing agent is preferably an isocyanate compound, an epoxy compound, an aziridine compound, a carbodiimide compound, or a metal chelate compound. When the crosslinkable functional group is an amino group, the curing agent is preferably an isocyanate compound, an epoxy compound, an aziridine compound, a carbodiimide compound, or a metal chelate compound. Furthermore, these hardening | curing agents can be used 1 type, or 2 or more types.

The above-mentioned curing agent is preferably used in an amount of 1 to 70 parts by weight, more preferably 5 to 60 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

In the present invention, the thermosetting resin (C) is preferably blended in an amount of 5 to 200 parts by weight with respect to 100 parts by weight of the copper powder contained in the reaction product of the present invention, that is, the surface-treated copper powder. 1
More preferably, 0 to 100 parts by weight are blended. Although the thermosetting resin can be a resistance component, it also has an effect of firmly fixing the surface-treated copper powder in contact. If it is the range of this mixing | blending, it is possible to make compatible the outstanding electroconductivity of this invention, and sufficient film-forming property.

The conductive composition of the present invention may further contain a solvent. By containing the solvent, the surface-treated copper powder can be easily dispersed and can be adjusted to a viscosity suitable for coating and printing. The solvent can be selected depending on the solubility of the resin used, the type of printing method, and the like.

Examples of such solvents include ester solvents, ketone solvents, glycol ether solvents, aliphatic solvents, alicyclic solvents, aromatic solvents, and alcohol solvents. Examples of the ester solvent include, but are not limited to, ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, and dimethyl carbonate. Examples of the ketone solvent include, but are not limited to, acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, diisobutyl ketone, diacetone alcohol, isophorone, and cyclohexanone. Examples of glycol ether solvents include ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monomethyl ether. Examples include, but are not limited to, ethyl ether and the like, and acetates thereof. Examples of the aliphatic solvent include n-
Examples include, but are not limited to, hexane, cyclohexane, methylcyclohexane, and octane. Examples of the aromatic solvent include, but are not limited to, toluene and xylene. You may use a solvent individually or in combination of 2 or more types.

In the present invention, the method of mixing the reaction product, that is, the surface-treated copper powder and the thermosetting resin (C) to obtain a conductive composition, as described above, is obtained after the completion of step 2. The reaction product of the present invention, that is, the slurry containing the surface-treated copper powder and the solvent may be prepared by adding the thermosetting resin (C), or the reaction product, that is, the surface-treated copper powder may be prepared from this slurry. May be isolated and mixed with the thermosetting resin (C) to prepare a conductive composition.

For the mixing and dispersion to obtain the conductive composition of the present invention, a disper, a homogenizer,
Although this roll, a 3 roll, etc. can be used, it is not limited to these.

The conductive composition of the present invention may be used in the form of a film on a substrate, and the film may form a pattern such as a circuit. In order to make the conductive composition into a film, a known coating method or printing method can be used. Specifically, gravure coating method, kiss coating method, die coating method, lip coating method, comma coating method, blade coating method, roll coating method, curtain coating method, knife coating method, spray coating method, bar coating method, spin coating method , Dip coating method, silk screen method, ink jet method and the like, but are not limited thereto. Moreover, when the electrically conductive composition of this invention contains a solvent, you may provide the drying process for removing a solvent as needed.

In the use of the conductive composition of the present invention, for the purpose of accelerating the curing of the thermosetting resin (C) and accelerating the contact and fusion of the reaction product, that is, the surface-treated copper powder, Different heating steps may be provided. This step may be any selected from air, an inert atmosphere, and a reducing atmosphere. Examples of the inert atmosphere include nitrogen, argon, and vacuum. Examples of the reducing atmosphere include, but are not limited to, hydrogen gas, formic acid vapor, or an atmosphere obtained by mixing these with an inert gas.

As a method for heating the conductive composition of the present invention, any known method may be used.
Examples include various ovens, hot plates, electric furnaces, flash xenon lamps, and the like, but are not limited thereto. Moreover, the temperature added by these heating methods is not specifically limited, either, It can set according to the use which the use of the electroconductive composition of this invention, such as an electrically conductive paste and an electromagnetic wave shield, is assumed. Furthermore, pressure may be applied simultaneously with overheating.

The thickness when the conductive composition of the present invention is used in the form of a film is not particularly limited, but is 1-1.
00 μm is preferable, and 3 to 50 μm is more preferable. If it is this range, favorable electroconductivity and oxidation resistance will be expressed reliably, and a favorable characteristic can be anticipated in the electromagnetic wave shield sheet and the electrically conductive paste with which the application of the electrically conductive composition of this invention is assumed.

In addition to the reactants, that is, the surface-treated copper powder and the thermosetting resin (C), the conductive composition of the present invention may further contain other known materials as necessary. Such materials include solvents, copper damage inhibitors, silane coupling agents, rust inhibitors, reducing agents, antioxidants, pigments, dyes, tackifying resins, plasticizers, UV absorbers, antifoaming agents, and leveling. Examples include regulators, fillers, and flame retardants.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, a part means a weight part and% means weight%.

  First, materials used in the examples and comparative examples of the present invention will be described.

(Copper powder (D))
The following two copper powders were used.
Copper powder (D-1): Copper powder (dendritic, particle size D50 = 10 μm)
Copper powder (D-2): Copper powder (flakes, particle size D50 = 7 μm)

Each of the copper powder (1) and the copper powder (2) is obtained by washing a commercially available copper powder with acetic acid in advance. That is, a slurry composed of 100 parts of glacial acetic acid and 100 parts of copper powder was stirred at room temperature for 1 hour, and then filtered under reduced pressure. The copper powder remaining on the filter paper was washed with acetone, then ion-exchanged water, and finally methanol. Later, it is a copper powder obtained by drying under reduced pressure.

(Compound (A))
The following two types of compounds (A) were used.
Compound (A-1): 5-carboxybenzotriazole (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)
Compound (A-2): A mixture comprising 5-carboxybenzotriazole and 4-carboxybenzotriazole (CBT-1, manufactured by Johoku Chemical Industry Co., Ltd.)

(Titanate coupling agent)
Table 1 shows 10 couplings used.

Table 1

(Principle confirmation of copper powder coated with compound (A))
It was confirmed by the following experiment that the copper powder coated with the compound (A) used in the present invention was reliably formed.

Compound (A-2) was added to 100 parts of 2-butanone in the amount shown in Table 2 and dissolved to obtain a solution containing compound (A-2). To this solution, 100 parts of copper powder (D-1) was added to form a slurry, which was stirred for 60 minutes at room temperature using a magnetic stirrer.

The supernatant of the slurry obtained here and the solution containing the compound (A-2) before adding the copper powder are analyzed using gas chromatography, and the peak areas of the compound (A-2) are compared. Thus, the reduction rate of the compound (A-2) contained in the solution, that is, the adsorption rate to the copper powder was calculated. The results are shown in Table 2.

From Table 2, it was confirmed that when the amount of the compound (A-2) is small, the total amount is 50% or more adsorbed on the surface of the copper powder even when the amount is relatively large. Therefore, it was confirmed that the copper powder coated with the compound (A-2) was reliably obtained at any concentration. Furthermore, when the copper powder obtained here was analyzed by XPS, N atoms derived from the compound (A-2) were detected on the surface of the copper powder, and this also indicates that the copper powder (D-1) is a compound ( It was supported that it was coated with A-2).

Table 2

Hereinafter, the Example regarding the reaction material of this invention, ie, surface-treated copper powder, and the manufacturing method for obtaining them is described.

Example 1 Reactant (1)
In 100 parts of 2-butanone, 0.1 part of the compound (A-2) was dissolved to obtain a solution containing the compound (A-2). To this solution, 100 parts of copper powder (D-1) was added to form a slurry, which was stirred for 60 minutes at room temperature using a magnetic stirrer. As described above, the slurry obtained here contained copper powder coated with the compound (A-2). To this slurry, 1 part of a titanate coupling agent (B-1) was added and reacted for 30 minutes while stirring at room temperature to obtain a reaction product. The reaction product obtained here corresponds to the surface-treated copper powder. This slurry was filtered under reduced pressure, and the reaction product remaining on the filter paper was sufficiently washed with 20 parts of 2-butanone and dried under reduced pressure at 40 ° C. to obtain 100 parts of the surface-treated copper powder (1). It was.

(Elements present on the surface of the reactant)
When elements present on the surface of the reactant (1) were confirmed by XPS, the compound (A-2)
In addition to the N atoms derived from the above, Ti atoms and P atoms derived from the titanate coupling agent were also confirmed. This was a result suggesting that the copper powder coated with the compound (A-2) reacted with the titanate coupling agent (B-1) to obtain a reaction product, that is, a surface-treated copper powder. .

(Evaluation of initial conductivity of reactant)
The conductivity of the reaction product obtained in Example 1 was evaluated. Specifically, 3.0 g of the reactant powder is put into the probe unit of the powder resistivity measurement system (Mitsubishi Chemical Analytech),
When the volume low efficiency when applying a pressure of 3 MPa was measured, it was 1 × 10 ⁻³ Ωcm, and it was confirmed that good initial conductivity was maintained even with the surface-treated copper powder. It was.

(Reactant in air-storage test under heating)
The reaction product obtained in Example 1 was placed in a petri dish, heated in the air in a hot air drying oven SPHH-202 (manufactured by Espec Corp.) for 30 minutes, and allowed to cool to room temperature. Thereafter, the volume resistivity of the powder was measured in the same manner as described above, and it was 5 × 10 ⁻³ Ωcm.

(Storage test under high temperature and high humidity in the reaction part)
The reaction product obtained in Example 1 was placed in a petri dish, stored in a thermo-hygrostat LHL-114 (manufactured by Espec Corp.) set at a temperature of 85 ° C. and a humidity of 85% for 2 hours, and allowed to cool to room temperature in a desiccator. After that, the volume resistivity of the powder was measured in the same manner as described above, and 3 × 10 ⁻³ was measured.
It was Ωcm.

(Examples 2 to 20 and Comparative Examples 1 to 13)
The same procedure as in Example 1 except that the compound (A-2), the copper powder (D-1), the titanate coupling agent (B-1) were replaced with the materials and parts by weight shown in Table 3. To obtain a reaction product. Furthermore, the initial conductivity of the reaction product, that is, the volume resistivity was measured by the method described above. Furthermore, the volume resistivity after the storage test under air-heating and after the storage test under high temperature and high humidity was also measured. The results are also shown in Table 3. For comparison, the first embodiment described above.
The results are also shown.

Table 3

From Table 3, the reaction product obtained according to the present invention, that is, the surface-treated copper powder, is a material that can maintain high conductivity by preventing oxidation even when exposed to air, heat, and humidity, which are copper deterioration factors. It became clear. This oxidation resistance was a level that greatly exceeded the oxidation resistance when the compound (A) or the titanate coupling agent (B) was used alone for the treatment of copper powder (Comparative Example). . It was also shown that the titanate coupling agent (B) has a specific improvement in oxidation resistance only when it has an alkyl group having 8 or more carbon atoms. Furthermore, it was also confirmed that a titanate coupling agent having a pyrophosphate ester residue was the reaction product with the highest oxidation resistance. In addition, it has been clarified that the reactant of the present invention is a material that is sufficiently protected by the coating film and also has excellent initial conductivity.

The reaction product obtained in Example 1 and Comparative Example 1, that is, the surface-treated copper powder was treated with XPS, respectively.
When the elements present on the surface were quantified, the reaction product (1) of Example 1 was confirmed to contain Ti atoms at a ratio of 3 times or more compared to the reaction product of Comparative Example 1. . This is an effect that the reaction point is enriched on the surface of the copper powder by the coating with the compound (A-2) and can react with more titanate coupling agents. As a result, the surface of the copper powder is densely covered with an oleophilic group and is isolated from the deterioration factors, so that the oxidation resistance of the copper powder is considered to be improved.

(Example 21)
In 100 parts of acetone, 0.1 part of the compound (A-2) was dissolved to obtain a solution containing the compound (A-2). To this solution, 100 parts of copper powder (D-1) was added to form a slurry, which was stirred for 60 minutes at room temperature using a magnetic stirrer. The obtained slurry contained copper powder coated with the compound (A-2). This slurry was filtered under reduced pressure, and the copper powder remaining on the filter paper was washed with 15 parts of acetone and dried under reduced pressure at room temperature to obtain 100 parts of copper powder coated with the compound (A-2).
To 100 parts of the copper powder obtained here, 100 parts of toluene was added to form a slurry, 1 part of titanate coupling agent (B-1) was added, and the mixture was allowed to react for 60 minutes while stirring at room temperature. Got. The reaction product obtained here corresponds to the surface-treated copper powder. This slurry was filtered under reduced pressure, and the reaction product remaining on the filter paper was washed with 20 parts of toluene and dried under reduced pressure at 40 ° C. to obtain a reaction product (21), that is, 100 parts of surface-treated copper powder.

(Example 22)
In 100 parts of acetone, 0.1 part of the compound (A-2) was dissolved to obtain a solution containing the compound (A-2). To this solution, 100 parts of copper powder (D-1) was added to form a slurry, which was stirred for 60 minutes at room temperature using a magnetic stirrer. As described above, the slurry obtained here contained copper powder coated with the compound (A-2). This slurry was filtered under reduced pressure, and the copper powder remaining on the filter paper was washed with 20 parts of acetone and dried under reduced pressure at room temperature to obtain 100 parts of copper powder coated with the compound (A-2).
100 parts of the copper powder obtained here and 1 part of the titanate coupling agent (B-1) were added, and the reaction product (22) was obtained by mixing and reacting in a V-type mixer for 60 minutes. .

With respect to the reactants obtained in Example 21 and Example 22, the initial conductivity, ie, volume resistivity, of the reactants was measured by the method described above. Furthermore, the volume resistivity after the storage test under air-heating and after the storage test under high temperature and high humidity was also measured. The results are also shown in Table 3.

From the results of Example 21 and Example 22, the copper powder coated with the compound (A) was isolated, dried, and then treated with a titanate coupling agent, which was good for the atmosphere, heat, and humidity. It became clear that a reaction product having oxidation resistance, that is, a surface-treated copper powder was obtained. Moreover, it became clear that the manufacturing method which processes the copper powder coat | covered with the compound (A) with a titanate coupling agent may be a dry type or a wet type.

Hereinafter, the conductive composition of the present invention will be described. The thermosetting resin in this example (
As C), the following materials were used.
(C-1) Thermosetting urethane resin (manufactured by Toyochem / acid value = 10 mgKOH / g)

(Example 23) Conductive composition Reactant (1) 3 produced by 100 parts of urethane resin (C-1) in the same manner as in Example 1
00 parts by weight, 4.5 parts by weight of decamethylene carboxylic acid disalicyloyl hydrazide (Adeka Stub CDA-6, ADEKA) as an additive were charged in a glass container, and the non-volatile content was 40
%, A mixed solvent of toluene and isopropyl alcohol (volume ratio 9: 1) was added. The mixture was stirred with a disper for 5 minutes to obtain a conductive composition.

After adding 10 parts by weight of a bisphenol A type epoxy resin (JER828, made by Japan Epoxy Resin) as a curing agent to 100 parts by weight of the conductive composition obtained above, stirring with a disper for 10 minutes, and then removing the polyethylene terephthalate A conductive composition formed into a film by coating with a bar coater so that the thickness after drying is 5 μm and drying in a hot air drying oven set at 100 ° C. for 2 minutes. A laminate was obtained.

(Evaluation of conductivity of conductive composition)
The film-shaped conductive composition laminate obtained above was cut into a 25 mm square both vertically and horizontally, and 2
The conductive composition was placed on the end of a stainless steel plate having a length of 5 mm, a length of 100 mm, and a thickness of 0.5 mm so that the surface of the conductive composition faced the stainless steel plate. Thereafter, the polyethylene terephthalate film is peeled off, and a stainless steel plate having the same size as the above is placed on the surface of the newly exposed conductive composition so as to have the structure shown in FIG.
Temporary pressure bonding was performed under the conditions of 0 ° C. and 2 MPa. This was subjected to thermocompression bonding at 150 ° C. and 2 MPa for 30 minutes to obtain an evaluation sample for evaluating the conductivity of the conductive composition.

The resistance value was measured by connecting a BSP probe to Lorester GP (manufactured by Mitsubishi Chemical Analytech) and bringing it into contact with two points indicated by arrows as 4 and 5 of the evaluation sample in FIG. The results are shown in Table 4.

(Storage test of conductive composition under high temperature and high humidity)
After the evaluation sample was stored for 5 days under high temperature and high humidity set at a temperature of 85 ° C. and a humidity of 85%, the resistance value was measured by the same method as described above. The results are also shown in Table 4.

(Examples 24-27, Comparative Examples 14-15)
A resistance value was measured for an evaluation sample obtained in the same manner as in Example 23 except that the conductive material was changed to the reactants shown in Table 4, that is, the surface-treated copper powder. Further, these evaluation samples were subjected to a storage test under the same high temperature and high humidity as described above, and the results of measuring the resistance values are also shown in Table 4.

Table 4

From Table 4, the reaction product of the present invention, that is, the conductive composition produced using them reflecting the excellent oxidation resistance of the surface-treated copper powder was also subjected to processes such as coating, drying and pressing. Later, good initial conductivity was exhibited. Furthermore, it was confirmed that these conductive compositions showed excellent wet heat resistance and had high reliability as a conductive film.

Although the reaction product obtained by the manufacturing method provided by the present invention, that is, the surface-treated copper powder, is inexpensive because it contains copper powder, it does not only have excellent initial conductivity but also various processes. High conductivity is maintained even after passing through the process, and it can sufficiently withstand long-term use under high temperature and high humidity.

Therefore, in various uses where silver powder, alloy powder, and copper powder coated with other metals are used as the conductive material, it is possible to use them in the form of replacing them.
Specifically, it is used for interlayer conduction means in via holes of multilayer printed wiring boards, conductive pastes and conductive inks for forming antennas and electronic circuit wiring parts on substrates, electromagnetic wave shield sheets, conductive master batches, etc. It is possible.

1: Conductive composition 2: Stainless steel plate 3: Stainless steel plate 4: Part in contact with electrode in evaluation of conductivity 5: Part in contact with electrode in evaluation of conductivity

Claims (5)

A reaction product of a copper powder coated with the compound (A) represented by the general formula (1) and a titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule.
General formula (1)
(Wherein R1 to R4 represent a hydrogen atom or a carboxyl group, provided that R1 to R4
At least one of 4 is a carboxyl group. ) The reactant according to claim 1, wherein the titanate coupling agent (B) having at least one alkyl group having 8 or more carbon atoms in the molecule is represented by the following general formula (2).
General formula (2)
(In the formula, n and m each independently represent a natural number, and n + m = 4 or 6.
R11 represents an alkoxy group having 1 to 8 carbon atoms when n = 1, and represents an alkoxy group having 1 to 8 carbon atoms when n is 2 or more, or R11 has two R11 and the following general formula The group represented by (3) or the group represented by the following general formula (4).
R12 represents a substituent selected from the following general formula (5) to the following general formula (9). )
General formula (3)
(Wherein R13 represents an alkylene group having 2 to 16 carbon atoms).
General formula (4)


(In the formula, R14 represents an alkylene group having 1 to 15 carbon atoms.)
General formula (5)
(In the formula, R21 represents an alkyl group having 8 to 30 carbon atoms.)
General formula (6)
(In the formula, R 31 and R 32 each independently represents an alkyl group having 8 to 30 carbon atoms.)
General formula (7)
(Wherein R41 and R42 each independently represents an alkyl group having 8 to 30 carbon atoms)
General formula (8)
(In the formula, R51 and R52 each independently represents an alkyl group having 8 to 30 carbon atoms.)
General formula (9)
(In the formula, R61 represents an alkyl group having 8 to 30 carbon atoms.)   The reactant according to claim 2, wherein the substituent R12 in the general formula (2) is the general formula (8).   The electroconductive composition containing the reaction material in any one of Claims 1-3, and a thermosetting resin (C). After the copper powder (D) is treated with a solution containing the compound (A) represented by the following general formula (1), the titanate coupling further having at least one alkyl group having 8 or more carbon atoms in the molecule The manufacturing method of the surface treatment copper powder processed with an agent (B).
General formula (1)
(Wherein R1 to R4 represent a hydrogen atom or a carboxyl group, provided that R1 to R4
At least one of 4 is a carboxyl group. )