JP2011046992A - Copper fine particle, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper fine particle which has excellent oxidation resistance, and in which a copper oxide is not formed on the surface thereof. <P>SOLUTION: The copper fine particle is characterized in that the surface is coated with a coating agent comprising a compound (A) expressed by general formula (1) (wherein, R<SP>1</SP>and R<SP>2</SP>are each independently hydrogen or 4-18C hydrocarbon group but R<SP>1</SP>and R<SP>2</SP>are not simultaneously hydrogen; R<SP>3</SP>and R<SP>4</SP>are each independently 1-6C alkyl or 2-4C hydroxyalkyl; and X<SP>+</SP>denotes a monovalent cation). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to copper fine particles and a method for producing the same. More specifically, the present invention relates to copper fine particles that are fine and have a uniform particle diameter and can be fired at a low temperature, and are particularly useful for wiring formation of electronic materials and anisotropic conductive adhesives.

  Conventionally, metal fine particles have been used for the formation of electronic circuits or conductive pastes for external electrodes of ceramic capacitors, the connection between printed wiring boards and electronic components, and the like. Examples of the conductive filler used in the conductive paste include copper, nickel, and silver. Among them, copper is inexpensive, has good conductivity, and is excellent in migration resistance. ing. In particular, metal fine particles having a particle size of 100 nm or less can be made extremely low in firing temperature unlike ordinary submicron or more particles, and therefore, application to low-temperature fired pastes and the like is being studied.

  Recently, a technique for printing a wiring pattern using an ink containing an ink jet printer with an ink containing metal fine particles and firing to form a wiring has been attracting attention, and research and development have been promoted. However, since copper paste is easily oxidized, sintering at a high temperature is required to restore the electrical conductivity, but this adversely affects the semiconductor. Accordingly, there is a need for copper fine particles having good oxidation resistance that can ensure conductivity by low-temperature sintering.

  As a method for obtaining copper fine particles, a copper oxide, hydroxide or salt is added in a solution of ethylene glycol, diethylene glycol or triethylene glycol, a noble metal ion is added for nucleation, and polyvinylpyrrolidone or the like is used as a dispersant. A method has been proposed in which an amine-based organic compound is added, an alkaline inorganic compound is added as necessary, and heat reduction is performed to obtain copper fine particles (see, for example, Patent Document 1). However, this method can obtain copper fine particles having a protective layer, but has a problem that the antioxidant property is not sufficient.

Japanese Patent Laid-Open No. 2005-240088

  This invention is made | formed in view of the said problem, and the subject of this invention is providing the copper fine particle excellent in oxidation resistance which does not produce | generate a copper oxide on the copper fine particle surface.

  As a result of intensive studies to solve the above problems, the present inventors have found that copper fine particles having excellent oxidation resistance can be obtained by coating the surface of the copper fine particles with a specific compound, and the present invention has been achieved. . That is, the present invention provides a copper fine particle characterized in that the surface is coated with a coating agent containing the compound (A) represented by the general formula (1), and water and / or an organic solvent. A copper compound and a reducing agent are reacted in the presence of the compound (A) represented by (1) or the coating agent containing the compound (B) represented by (A) and the general formula (5). This is a method for producing copper fine particles characterized by depositing metallic copper.

[Wherein, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms, and R ¹ and R ² are not simultaneously hydrogen atoms, and R ³ and R ⁴ are Each independently an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, and X ⁺ is a monovalent cation. ]

[Wherein, R ⁸ and R ⁹ are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms, and R ⁸ and R ⁹ do not simultaneously become a hydrogen atom, and Y ⁺ and Z ⁺ are Each is independently a monovalent cation. ]

  Since the copper particles of the present invention are excellent in oxidation resistance and are in the form of fine particles, there is an effect that the firing temperature can be extremely lowered.

R ¹ and R ² in the compound represented by the general formula (1) covering the surface of the copper fine particles of the present invention are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms. However, R ¹ and R ² are not simultaneously hydrogen atoms, one is a hydrogen atom and the other is a hydrocarbon group having 4 to 18 carbon atoms, or both are hydrocarbon groups having 4 to 18 carbon atoms.
Examples of the hydrocarbon group having 4 to 18 carbon atoms include aliphatic hydrocarbon groups and aromatic hydrocarbon groups having 4 to 18 carbon atoms.

  Examples of the aliphatic hydrocarbon group having 4 to 18 carbon atoms include a linear or branched chain hydrocarbon group and an alicyclic hydrocarbon group.

Examples of the linear hydrocarbon group having 4 to 18 carbon atoms include a linear alkyl group and a linear alkenyl group. Examples of the linear alkyl group include a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, an undecyl group, a dodecyl group, a tetradecyl group, a pentadecyl group, and an octadecyl group.
Examples of the linear alkenyl group include a butenyl group, a hexenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, and an oleyl group.

Examples of the branched hydrocarbon group having 4 to 18 carbon atoms include branched alkyl groups and branched alkenyl groups. As the branched alkyl group, t-butyl group, 2-ethylhexyl group, 2,4,6-trimethylheptyl group, 2,4,6,8-tetramethylnonyl group, 2-n-butyltetradecyl group And a residue obtained by removing a hydrogen atom from a hydrogenated propylene tetramer or a hydrogenated butene trimer.
Examples of branched alkenyl groups include t-butenyl group, 2-ethylhexenyl group, 2,4,6-trimethylheptenyl group, 2,4,6,8-tetramethylnonenyl group, 2-n-butyltetra. Examples thereof include a residue obtained by removing a hydrogen atom from a decenyl group and propylene tetramer or butene trimer.

 Examples of the alicyclic hydrocarbon group having 4 to 18 carbon atoms include a cyclohexyl group, a cyclohexenyl group, and a cycloheptyl group.

  Examples of the aromatic hydrocarbon group having 4 to 18 carbon atoms include phenyl group, xylyl group, naphthyl group, octylphenyl group, and nonylphenyl group.

Among R ¹ and R ² , from the viewpoint of oxidation resistance on the copper surface and easy availability of raw materials, it is preferable that either one is a hydrogen atom and the other is a hydrocarbon group of 4 to 18, Of the 4 to 18 hydrocarbon groups, an aliphatic hydrocarbon group having 8 to 18 carbon atoms is more preferable, and a linear or branched alkenyl group having 8 to 18 carbon atoms is particularly preferable.

If one of R ¹ and R ² is a hydrogen atom, R ¹ and R ² in the general formula (1) may be either a hydrocarbon group, those wherein R ¹ is a hydrocarbon group alone, R ² is a hydrocarbon group Or a mixture of these may be used.

R ³ and R ⁴ in the general formula (1) are each independently an alkyl group or a hydroxyalkyl group having 2 to 4 carbon atoms having 1 to 6 carbon atoms.
Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, and a hexyl group. As the hydroxyalkyl group having 2 to 4 carbon atoms, Examples include 2-hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, 4-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, and 3-hydroxy-2-methylpropyl group. Among these, from the viewpoint of excellent oxidation resistance on the copper surface, a hydroxyalkyl group having 2 to 4 carbon atoms is preferable, and a 2-hydroxyethyl group is particularly preferable.

X ⁺ in the general formula (1) is a monovalent cation, a proton, an alkali metal cation, an ammonium cation, a cation obtained by adding a proton to an amine having 1 to 12 carbon atoms, and a quaternary ammonium cation having 4 to 12 carbon atoms. Is mentioned.

  Examples of the alkali metal cation include sodium cation, potassium cation, lithium ion and cesium cation.

  Examples of the amine constituting the cation in which a proton is added to an amine having 1 to 12 carbon atoms include carbon such as monomethylamine, monoethylamine, diethylamine, triethylamine, mono-n-butylamine, di-n-butylamine and tri-n-butylamine. Mono-, di- or trialkylamines having 1 to 12 carbon atoms; alicyclic amines having 4 to 12 carbon atoms such as cyclohexylamine and 1,4-cyclohexanediamine; heterocyclic amines having 4 to 12 carbon atoms such as morpholine and piperazine And hydroxyalkyl group-containing amines represented by the following general formula (2).

In the formula, R ⁵ is a hydrogen atom, a monovalent or divalent hydrocarbon group having 1 to 18 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, R ⁶ is a hydrogen atom, monovalent having 1 to 18 carbon atoms. hydrocarbon group or a hydroxyalkyl group having 2 to 4 carbon atoms, R ⁷ is an alkylene group having 2 to 4 carbon atoms, p is R ⁵ is a hydrogen atom, the number monovalent hydrocarbon group or a C 1 to 18 carbon atoms 2 1 in the case of a -4 hydroxyalkyl group, and 2 in the case where R ⁵ is a divalent hydrocarbon group having 1 to 18 carbon atoms.

As the monovalent hydrocarbon group having 1 to 18 carbon atoms in R ⁵ and R ^6, in addition to the hydrocarbon group having 4 to 18 carbon atoms exemplified as R ¹ in the general formula (1), a methyl group, An ethyl group and a propyl group are mentioned.
As the divalent hydrocarbon group having 1 to 18 carbon atoms in R ^5, in addition to the alkylene group having 2 to 4 carbon atoms exemplified as R ³ in the general formula (1), a methylene group, a pentamethylene group, Linear alkylene groups such as hexamethylene group, octamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tetradecamethylene group, pentadecamethylene group and octadecamethylene group; propenylene group, butenylene group, hexenylene group , Linear alkenylene groups such as octenylene group and octadecenylene group; branched structures such as 2-ethylhexylene group, 2,4,6-trimethylheptylene group and 2,4,6,8-tetramethylnonylene group Alkylene group; branched alkyl such as 2-methylpropenylene group, 2,2-dimethylbutenylene group and 2-methyloctenylene group Kenylene group; bivalent alicyclic hydrocarbon group such as 1,4-cyclohexylene group, 1,4-cycloheptylene group and 1,4-cyclohexanedimethylene group; divalent groups such as phenylene group, xylylene group and naphthylene group And aromatic hydrocarbon groups.

R ⁵ is preferably a hydrogen atom or a monovalent or divalent aliphatic hydrocarbon group having 2 to 12 carbon atoms from the viewpoint of oxidation resistance, and more preferably a hydrogen atom or 3 to 12 carbon atoms. Are a divalent chain hydrocarbon group and a monovalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, particularly preferably a hydrogen atom or a cyclohexyl group.

Examples of the hydroxyalkyl group having 2 to 4 carbon atoms in R ⁶ include a 2-hydroxyethyl group, a 3-hydroxypropyl group, a 2-hydroxypropyl group, a 4-hydroxybutyl group, a 2-hydroxybutyl group, and a 3-hydroxybutyl group. And 3-hydroxy-2-methylpropyl group and the like.

R ⁶ is preferably a hydrogen atom, an aliphatic hydrocarbon group having 2 to 12 carbon atoms and a hydroxyalkyl group having 2 to 4 carbon atoms from the viewpoint of oxidation resistance, and more preferably a hydrogen atom or carbon atom. A chain hydrocarbon group having 3 to 12 carbon atoms, an alicyclic hydrocarbon group having 6 carbon atoms and a hydroxyalkyl group having 2 to 4 carbon atoms are particularly preferable, and a 2-hydroxyethyl group is particularly preferable.

Examples of the alkylene group having 2 to 4 carbon atoms for R ⁷ include the same groups as those exemplified for R ³ .

Of R ⁷ , ethylene, 1,3-propylene and 1,2-propylene are preferred from the viewpoint of easy availability of raw materials, and ethylene is more preferred.

p is 1 when R ⁵ is a hydrogen atom, a monovalent hydrocarbon group having 1 to 18 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, and R ⁵ is a divalent hydrocarbon group having 1 to 18 carbon atoms. In the case of 2.

  Specific examples of the amine represented by the general formula (2) include monoalkanolamines [monoethanolamine, monoisopropanolamine, monobutanolamine and the like]; dialkanolamines [diethanolamine, diisopropanolamine and N-hydroxyethylisopropanolamine] Etc.]; trialkanolamine [triethanolamine, N-hydroxyethyldiisopropanolamine etc.]; monoalkanol alkylamine [monoethanolethylamine, monoisopropanolethylamine and monoethanolbutylamine etc.]; monoalkanol cycloalkylamine [monoethanolcyclohexylamine] Monoisopropanol cyclohexylamine and mono n-butanol cyclohexylamine, etc.]; dialkanol Chloalkylamines [N, N-bis (2-hydroxyethyl) -N-cyclohexylamine, N, N-bis (2-hydroxyisopropyl) -N-cyclohexylamine and N, N-bis (2-hydroxyisobutyl)- N-cyclohexylamine etc.]; tetraalkanol alkylene diamine [N, N, N ′, N′-tetrakis (2-hydroxyethyl) ethylenediamine and N, N, N ′, N′-tetrakis (2-hydroxyethyl) -1 , 6-hexamethylenediamine, etc.].

X ⁺ is preferably a sodium cation, a potassium cation, a cation obtained by adding a proton to an amine having 1 to 12 carbon atoms, or an amine represented by the general formula (2) from the viewpoint of excellent water solubility and low odor. From the viewpoint of oxidation resistance of the copper surface, a cation having a proton added thereto is more preferable. A cation having a proton added to an amine having 1 to 4 carbon atoms and a proton added to an amine represented by the general formula (2) are more preferable. Particularly preferred is a cation obtained by adding a proton to an amine represented by the general formula (2).

  Specific examples of the compound (A) represented by the general formula (1) include sodium salt of dodecenyl succinic acid diethanolamide, diethanolamine salt of dodecenyl succinic acid diethanolamide, N, N-bis (2-hydroxyethyl) of dodecenyl succinic acid diethanolamide. ) -N-cyclohexylamine salt, N, N-bis (2-hydroxyethyl) -N-cyclohexylamine salt of octenyl succinic acid diethanolamide, N, N, N ', N'-tetrakis (2- Hydroxyethyl) ethylenediamine salt, N, N-bis (2-hydroxyethyl) -N-cyclohexylamine salt of pentadecenyl succinic acid diethanolamide, N, N, N ′, N′-tetrakis of dodecenyl succinic acid diethanolamide ( 2- Dorokishiechiru) -1,6-hexamethylenediamine salt, and diethanolamine salts of dodecenylsuccinic acid diethylamide, and the like.

  The compound (A) can be produced by a method of reacting the compound represented by the general formula (4) with the acid anhydride represented by the general formula (3).

In the formula, R ¹ and R ² are the same as R ¹ and R ² in the general formula (1).

Wherein, R ³ and R ⁴ are the same as R ³ and R ⁴ in the general formula (1).

  The charging molar ratio of the compound represented by the general formula (4) to the acid anhydride represented by the general formula (3) is preferably 1 / 1.0 to 1 / 3.0. The reaction is preferably performed at a temperature of −5 to 150 ° C., a pressure of 0 to 0.6 MPa, and a reaction time of 2 to 15 hours. When the reaction temperature is high, an ester compound is easily produced as a by-product, and therefore it is particularly preferable to react at −5 to 80 ° C.

  Although the coating agent in this invention may consist only of the compound (A) represented by General formula (1), it may contain the compound (B) represented by General formula (5) further. .

R ⁸ and R ⁹ in the general formula (5) are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms, and R ⁸ and R ⁹ do not simultaneously become a hydrogen atom. The hydrocarbon group having 4 to 18 carbon atoms, the general formula (1) the same as those exemplified as R ¹ and R ² can be mentioned in, preferable ones are also same.
Y ⁺ and Z ⁺ are each independently a monovalent cation, and examples thereof include those exemplified as X ⁺ in the general formula (1), and preferred ones are also the same.

  Specific examples of the compound (B) include mono- or disodium salt of dodecenyl succinic acid, mono- or didiethanolamine salt of dodecenyl succinic acid, mono- or di-N, N-bis (2-hydroxyethyl) -N-cyclohexylamine of dodecenyl succinic acid Salts, mono-N, N, N ′, N′-tetrakis (2-hydroxyethyl) ethylenediamine salt of dodecenyl succinic acid and mono-N, N, N ′, N′-tetrakis (2-hydroxyethyl) -1, dodecenyl succinic acid, Examples include 6-hexamethylenediamine.

  When the coating material contains the compound (B), the content is preferably 0.1 to 40% by weight, more preferably 0.1 to 0.1% by weight based on the total weight of the compound (A) and the compound (B). 20% by weight.

  The compound (B) can be obtained by reacting the compound represented by the general formula (4) with a dicarboxylic acid obtained by hydrolyzing the acid anhydride represented by the general formula (3).

In the presence of a coating agent containing the compound (A) represented by the general formula (1) in water and / or an organic solvent, the copper compound and the reducing agent are reacted to precipitate metal copper fine particles, The copper fine particles coated with the coating agent containing the compound (A) can be obtained by solid-liquid separation, washing with water, and drying.
Moreover, the copper fine particle coat | covered with the coating agent which consists of a compound (A) and a compound (B) similarly by making the coating agent further contain the compound (B) represented by General formula (5). Can do.
Whether the copper fine particles are coated with the compound (A) or the like can be confirmed by measuring the infrared absorption spectrum of the copper surface.

There is no restriction | limiting in particular as water, Tap water, ion-exchange water, ultrapure water, distilled water, etc. can be used.
Examples of the organic solvent include monovalent or divalent alcohols having 1 to 6 carbon atoms (methyl alcohol, ethyl alcohol, n- or iso-propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, etc.) and C3-C9 ketones (acetone, ethyl methyl ketone, etc.).

  Examples of the copper compound include copper oxides, chlorides, sulfates, nitrates, carbonates and acetates.

  Known reducing agents can be used, such as (1) hydrazine or hydrates thereof, (2) hydrazine compounds (such as hydrazine hydrochloride and hydrazine sulfate), (3) aldehydes [(a) fats Aromatic aldehydes (formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, etc.), (b) aromatic aldehydes (benzaldehyde, etc.) and (c) heterocyclic aldehydes, etc.], (4) amines [(a ) Primary amines (such as butylamine, ethylamine, propylamine, and ethylenediamine), (b) Secondary amines (such as dibutylamine, diethylamine, and dipropylamine), (c) Tertiary amines (tributylamine, triethylamine, and tributylamine) Propylamine, etc.)], (5) aminoaldehyde (6) Alkanolamines (such as ethanolamine, diethanolamine and triethanolamine), (7) Reducing sugars (such as sucrose, treperth, maltose and lactose), (8) Hydrogen compounds (hydrogenated) (9) Low-order inorganic oxygen acids (sulfurous acid, nitrous acid, hyponitrous acid, phosphorous acid, hypophosphorous acid, etc.) and their hydrates (bisulfite, etc.) or their salts (such as sodium) Alkali metal salts etc.) and the like, and these may be used alone or in combination of two or more.

  The concentration of the copper compound in water and / or the organic solvent is not particularly limited as long as the copper compound is dissolved or dispersed, but is preferably 5 mmol / liter or more from the viewpoint of productivity.

  The usage-amount of a coating agent is 10-5000 weight part with respect to 100 weight part of copper compounds from a viewpoint of oxidation resistance and cost.

  The amount of the reducing agent used is from 10 to 2000 parts by weight, preferably from 20 to 1,000 parts by weight, based on 100 parts by weight of the copper compound, from the viewpoint of the reduction reaction rate, the particle diameter control of the produced copper particles and the cost. .

  The temperature during the reduction reaction is desirably maintained at about 10 to 90 ° C, more preferably 40 to 60 ° C. If the temperature is less than 10 ° C, the reduction reaction proceeds slowly. If the temperature exceeds 90 ° C, the reaction becomes intense and secondary nuclei are likely to be generated, and the particle size tends to be difficult to control.

The pH of the solution or dispersion during the reduction reaction is preferably 7 to 14, more preferably 8 to 13, particularly preferably 8 from the viewpoint of improving the solubility or uniform dispersibility of the copper compound and the efficiency of the reduction reaction. ~ 12.
For pH adjustment, basic compounds such as hydroxides or carbonates of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide and calcium hydroxide, ammonia and amines can be used.

The method of solid-liquid separation is not particularly limited, and examples thereof include a method using a filter or a centrifuge.
As a drying method, it can be performed using a known facility such as a fluidized bed dryer, a vacuum dryer, and a circulating dryer. The drying temperature is usually 30 to 200 ° C., preferably 50 to 100 ° C., and the drying time is usually 1 to 10 hours, preferably 2 to 5 hours.

  The preferred range of the average particle size of the copper fine particles of the present invention varies depending on the application to be used, but the desired average particle in the range of 1 nm to 100 μm can be adjusted by adjusting the concentration of the reducing agent and the coating agent and the stirring speed during the reduction reaction. The diameter can be adjusted as appropriate.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. Below, a part represents a weight part.

[Example 1]
25.5 parts of copper chloride was dissolved in 750 parts of ion-exchanged water, 15 parts of a coating agent represented by the following structural formula (6) was added, and the mixture was heated to 40 ° C. with stirring. Thereafter, 750 parts of a 5% hydrazine aqueous solution and 22.5 parts of ammonia were added as reducing agents, the pH was adjusted to 10, the temperature was raised to 60 ° C. over 1 hour, and the reduction reaction proceeded while maintaining at 60 ° C. for 1 hour. . The reaction solution was subjected to solid-liquid separation with a centrifugal separator, and the collected solid content was washed with water and dried to obtain copper fine particles.

[Example 2]
Copper fine particles were obtained in the same manner as in Example 1 except that the coating agent represented by the structural formula (6) was replaced with the coating agent represented by the following structural formula (7).

[Example 3]
25.5 parts of copper nitrate was dissolved in 750 parts of ion-exchanged water, 15 parts of the coating agent represented by the structural formula (6) was added, and the mixture was heated to 40 ° C. with stirring. Thereafter, 750 parts of a 5% hydrazine aqueous solution and 22.5 parts of ammonia were added as reducing agents, the pH was adjusted to 10, the temperature was raised to 60 ° C. over 1 hour, and the reduction reaction proceeded while maintaining at 60 ° C. for 1 hour. . The reaction solution was subjected to solid-liquid separation with a centrifugal separator, and the collected solid content was washed with water and dried to obtain copper fine particles.

[Comparative Example 1]
Copper fine particles were obtained in the same manner as in Example 1 except that the coating agent represented by the structural formula (6) was replaced with polyvinylpyrrolidone having a weight average molecular weight of 3000.

[Comparative Example 2]
Copper fine particles were obtained in the same manner as in Example 1 except that the coating agent represented by the structural formula (6) was replaced with oleic acid.

The infrared absorption spectra of the surfaces of the copper fine particles obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were measured, and it was confirmed that they were coated with the respective coating agents used.
Table 1 shows the results of measuring the average particle diameter and conductivity of the copper particles obtained in Examples 1 to 4 and Comparative Examples 1 and 2 by the following test method.
<Measurement method of average particle diameter>
Using a scanning electron microscope ["JSM-7000" manufactured by JEOL Ltd.], 200 copper fine particles were randomly selected from the field of view at a shooting magnification of 100,000, and the particle diameter was measured. The value was defined as the average particle size.

<Measurement method of conductivity>
1.33 parts of copper fine particles, 0.12 part of polyvinylidene fluoride and 0.88 part of N-methylpyrrolidone were mixed and applied to a glass plate so that the film thickness after drying was 100 μm, and then at 80 ° C. for 30 minutes. It was dried under reduced pressure. After the obtained coating film was air-cooled, the conductivity of the coating film was measured using a Loresta-GP type low resistivity meter (manufactured by Mitsubishi Chemical Corporation). The larger the conductivity, the higher the conductivity.

  The copper fine particles of the present invention can prevent formation of fine wiring and can form a conductor excellent in electrical stability, and are useful for forming wiring of electronic materials and anisotropic conductive adhesives.

Claims (7)

A copper fine particle, the surface of which is coated with a coating agent containing the compound (A) represented by the general formula (1).
[Wherein, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms, and R ¹ and R ² are not simultaneously hydrogen atoms, and R ³ and R ⁴ are Each independently an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, and X ⁺ is a monovalent cation. ] ^2. The copper fine particles according to claim 1, wherein one of R ¹ and R ² in the general formula (1) is a hydrogen atom and the other is an alkenyl group having 8 to 18 carbon atoms. The copper fine particles according to claim 1 or 2, wherein R ³ and R ⁴ in the general formula (1) are a hydroxyalkyl group having 2 to 4 carbon atoms. The copper particles according to claim 1, wherein X ⁺ in the general formula (1) is a monovalent cation obtained by adding a proton to the amine represented by the general formula (2).
[Wherein R ⁵ is a hydrogen atom, a monovalent or divalent hydrocarbon group having 1 to 18 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, R ⁶ is a hydrogen atom, monovalent having 1 to 18 carbon atoms. hydrocarbon group or a hydroxyalkyl group having 2 to 4 carbon atoms, R ⁷ is an alkylene group having 2 to 4 carbon atoms, p is R ⁵ is a hydrogen atom, a monovalent hydrocarbon group or a carbon number of 1 to 18 carbon atoms It is 1 in the case of 2 to 4 hydroxyalkyl groups, and 2 in the case where R ⁵ is a divalent hydrocarbon group having 1 to 18 carbon atoms. ] The coating agent further contains the compound (B) represented by the general formula (5), and the ratio of the compound (B) to the total weight of the compound (A) and the compound (B) is 0.1. The copper fine particle according to any one of claims 1 to 4, which is -40% by weight.
[Wherein, R ⁸ and R ⁹ are each independently a hydrogen atom or a hydrocarbon group having 4 to 18 carbon atoms, and R ⁸ and R ⁹ do not simultaneously become a hydrogen atom, and Y ⁺ and Z ⁺ are Each is independently a monovalent cation. ]   Presence of a coating agent containing the compound (A) represented by the general formula (1) or the compound (B) represented by the (A) and the general formula (5) in water and / or an organic solvent. The method for producing copper fine particles according to any one of claims 1 to 5, wherein metal copper is precipitated by reacting a copper compound with a reducing agent.   The method for producing copper fine particles according to claim 6, wherein the pH of the solution or dispersion at the start of the reduction reaction is 7 to 14.