CN104981427A - Fine copper nitride particles and production method therefor - Google Patents

Abstract

The object of the present invention is to develop copper nitride fine particles that can be decomposed into copper and nitrogen below 300°C. The present invention relates to copper nitride microparticles and a method of producing the same which do not have essentially the instability and high temperature processing problems of metallic copper. Copper nitride microparticles having a primary particle diameter of 1 to 100 nm and a decomposition temperature of 300° C. or lower. The particle size of the secondary particles is preferably 1 μm or less.

Description

Copper nitride particles and manufacturing method thereof

technical field

The present invention relates to copper nitride fine particles, a method for producing the same, and an ink material for wiring and a printed substrate using copper nitride fine particles.

Background technique

In recent years, as a method of forming wiring and electrode films that can reduce the number of steps necessary for pattern formation of electronic devices, realize mass production, and reduce costs, screen printing or inkjet printing is used to form wiring patterns. With the development of electronic device technology, research on metal wiring materials, which are one of the core materials of the technology, has been actively conducted. At present, studies have been conducted mainly on silver nanoparticles, but since silver has high ion mobility and high price, a wiring method using copper nanoparticles, which should be able to solve this problem, has been tried. However, copper is not only easily oxidized and unstable, but also needs to be treated at a high temperature above 350°C after printing in order to exhibit electrical conductivity, so it cannot be used in high-temperature materials such as polyimide or polyethylene terephthalate. Wiring on the molecular substrate. In this way, there are still some problems to be overcome in order to put copper printed wiring into practical use.

At present, researches on copper nitride crystals are conducted for the purpose of use as memory materials (Non-Patent Document 1).

In addition, since the copper nitride crystal has oxidation resistance, it is prepared as an oxidation-resistant film of metallic copper, and patents related to its production method have been applied for (Patent Document 1, Patent Document 2).

Conventional methods for producing these copper nitrides mainly utilize solid-state reactions, and they are produced by contacting inorganic copper salts such as copper chalcogenides and metallic copper with ammonia gas at high temperature (Non-Patent Document 2).

Regarding the liquid-phase synthesis of copper nitride particles, as described in Non-Patent Document 3, sodium azide and copper inorganic salts are used as raw materials, in toluene solvent, using a pressure-resistant container, and heated under spontaneous pressure to synthesize copper nitride. However, since such a production method requires a pressure-resistant container, strict control of reaction temperature and pressure is required, and there is a risk of explosion, it cannot be said to be a very simple method.

In addition, the method shown in Non-Patent Document 4 shows a reaction under normal pressure using a compound containing a nitrogen atom as a solvent. However, this document uses octadecylamine with a high boiling point (boiling point 232° C. at an air pressure of 32 mmHg) as a solvent and a surface modifier, and reacts at a reaction temperature of 280° C. The copper nitride particles obtained from this document are not suitable for low-temperature wiring materials, one of the utilization purposes of the copper nitride particles, because a large amount of high-boiling point surface modifier remains on the surface of the copper nitride particles.

prior art literature

patent documents

Patent Document 1: Japanese Patent No. 3870273

Patent Document 2: Japanese Patent Laid-Open No. 2011-12339

non-patent literature

Non-Patent Document 1: Japanese Journal of Applied Physics, 1990, 29, 1985-1986.

Non-Patent Document 2: Solid State Science, 2007, 9, 907-913.

Non-Patent Document 3: Inorganic Chemistry, 2005, 44, 7385-7393.

Non-Patent Document 4: Chemical Communications, 2012, 47, 3604-3606.

Contents of the invention

In view of the above-mentioned prior art, the object of the present invention is to develop copper nitride particles that decompose into copper and nitrogen below 300°C, and copper nitride particles can be efficiently produced even without pressure treatment or vacuum treatment. The present invention relates to copper nitride fine particles that do not substantially have the problems of instability and high-temperature treatment of metallic copper, and a method for producing the same.

Copper nitride has oxidation resistance, and it is decomposed into copper and nitrogen at a temperature below 350° C. to form metallic copper in a block state. This is known to all, and the inventors have noticed that it solves the shortcomings of metallic copper. Material. Then, the inventors of the present invention conducted intensive studies in order to solve the above-mentioned problems. As a result, they found that a compound having a primary particle diameter of 100 nm or less can be prepared by coexisting a compound serving as a copper source and a compound serving as a nitrogen source in an organic solvent and heating them. Copper nitride fine particles, the decomposition temperature of the obtained copper nitride fine particles is 300° C. or lower, and the present invention has been completed.

That is, the present invention provides the following inventions in order to solve the above-mentioned problems.

[1] Copper nitride microparticles having a primary particle diameter of 1 to 100 nm and a decomposition temperature of 300° C. or lower.

[2] The copper nitride fine particles according to the above [1], wherein the particle size of the secondary particles is 1 μm or less.

[3] The copper nitride fine particles according to the above [1] or [2], which have a decomposition temperature in the range of 70° C. to 300° C. accompanied by weight loss in differential thermal balance analysis.

[4] The copper nitride fine particles according to any one of the above [1] to [3], wherein the secondary particles are spherical in electron microscope observation.

[5] The copper nitride particles according to any one of the above [1] to [4], in powder X-ray diffraction, 21.5 to 24.5°, 31.0 to 34.0°, 39.0 to 42.0° and There is at least one diffraction peak derived from copper nitride in any region of 46.0° to 49.0°.

[6] A method for producing copper nitride particles, characterized in that the copper source and nitrogen source, or copper source, nitrogen source and protective agent are dissolved or dispersed in a solvent or dispersion medium, and then heated to produce the above-mentioned The copper nitride fine particles according to any one of [1] to [5].

[7] The method for producing copper nitride fine particles according to the above [6], wherein the copper source contains one or more selected from inorganic copper salts, organic copper salts, and copper complexes.

[8] The method for producing copper nitride particles according to the above [6] or [7], wherein the nitrogen source includes ammonia gas or ammonium salt compounds, urea, urea derivative compounds, nitrate compounds, amine compounds And one or more kinds of azide compounds.

[9] The method for producing copper nitride fine particles according to any one of the above [6] to [8], wherein the copper source and the nitrogen source are bonded or coordinated to form a nitrogen-containing copper complex.

[10] The method for producing copper nitride fine particles according to any one of the above [6] to [9], wherein the protective agent is a compound having at least one carboxyl group, amino group and/or hydroxyl group.

[11] The method for producing copper nitride fine particles according to any one of the above [6] to [10], wherein the solvent is an organic solvent having a boiling point of 100° C. or higher.

[12] The method for producing copper nitride fine particles according to any one of the above [6] to [11], wherein the heating temperature is 100 to 250°C.

[13] The method for producing copper nitride microparticles according to any one of the above [6] to [12], wherein the concentration of the copper source relative to the solvent is 0.0001 in terms of Cu ¹⁺ or Cu ²⁺ ~1mol/L.

[14] An ink material for wiring, comprising the copper nitride fine particles according to the above [1].

[15] A substrate to be printed on which the ink material for wiring according to the above [14] is coated.

[16] A substrate to be printed obtained by heating the substrate to be printed as described in [15] above to form a metallic copper film from copper nitride particles.

According to the present invention, it is possible to provide copper nitride fine particles that do not substantially have the problems of instability and high-temperature treatment of metallic copper, and a method for producing the same. Since the copper nitride fine particles can be wired by printing and have oxidation resistance against air and water, it is possible to provide a material that exhibits conductivity after heat treatment at 300°C or less by drawing wiring on a thin film by printing or the like.

Description of drawings

Fig. 1 is the XRD pattern of the copper nitride particles obtained in Example 1, and the XRD patterns of copper, copper oxide and copper nitride.

Fig. 2 is the XRD pattern of the copper nitride particles obtained in Examples 1, 2, 3 and 8.

FIG. 3 is a TEM observation image of copper nitride fine particles obtained in Example 1. FIG.

FIG. 4 is a TEM observation image of copper nitride fine particles obtained in Example 3. FIG.

5 is a spectrum of differential thermal balance analysis (atmospheric pressure and reduced pressure) of the copper nitride fine particles obtained in Example 1. FIG.

Detailed ways

The copper nitride fine particles of the present invention have a primary particle diameter of 1 to 100 nm and a decomposition temperature of 300° C. or lower.

The primary particle diameter of the copper nitride particles of the present invention is 1-100 nm, which means that in electron microscope observation, at least the minor axis diameter of the primary particles is 1-100 nm, which is necessary to reduce the decomposition temperature of the copper nitride particles The primary particle size thereof is preferably 50 nm or less, more preferably 30 nm or less, further preferably 20 nm or less, and most preferably 10 nm or less.

The particle size of the secondary particles is preferably 1 μm or less. For example, when used as an inkjet ink, the ink has good applicability and can pass through the ink nozzle without clogging the ink nozzle. The form of the secondary particles is preferably a substantially spherical particle form, for example, when used as a coating solution, it has excellent fluidity and is suitable for dense packing after coating. The spherical shape may not be completely spherical, and may have an aspect ratio such that there is a difference between the major axis and the minor axis such that the aspect ratio is, for example, about 3 or less, preferably about 1.5 or less. The particle shape of the primary particles may be any particle shape such as angular shape, needle shape, rice grain shape, etc., but the secondary particle is preferably in a shape that tends to be spherical.

The copper nitride fine particles of the present invention have a decomposition temperature in the range of 70°C to 300°C in a differential thermal balance analysis (atmospheric pressure) accompanied by a decrease in weight (mass). The decomposition temperature is below 300°C, which can bring the following advantages: when the copper nitride particles are used as the ink material for wiring, and the polymer substrate or film is used as the substrate to be printed, after heat treatment, the substrate to be printed The material can be processed at a temperature that does not suffer heat-induced damage, for example, does not undergo melting and/or deformation, decomposition, carbonization.

The copper nitride particles of the present invention have the following copper nitride (Cu ₃ N) crystal structure: in powder X-ray diffraction, 21.5-24.5° and 31.0-34.0°, 39.0-42.0°, 46.0-49.0° under the CuKα line There is at least one diffraction peak derived from copper nitride in any region of °.

The copper nitride fine particles described in the present invention may be provided in the form of powder or colloidal dispersion, and an appropriate protective agent may be used to impart dispersibility and stability to the copper nitride fine particles.

The copper nitride fine particles of the present invention can be obtained by dissolving or dispersing a copper source and a nitrogen source, or a copper source, a nitrogen source and a protective agent in an organic solvent or a dispersion medium, and then heating.

As a copper-containing compound used as a copper source, the following are exemplified such as inorganic copper salts, organic copper salts, or copper complexes. The oxidation number of copper contained in the copper salts or copper complexes is one. Either state of valence or bivalence is acceptable. In addition, in order to stabilize copper salts or copper complexes, the number of molecules coordinated to the copper element may be any number from 0 to 6.

Examples of inorganic copper salts include copper chloride, copper bromide, copper iodate, copper iodide, copper fluoride, basic copper carbonate, copper cyanide, copper azide, copper ammonium chloride, hydrogen Copper oxide, copper formate, copper oxychloride, copper perchlorate, copper phosphate, potassium copper chloride, copper sulfate, basic copper sulfate, copper sulfate, copper sulfide, etc. In addition, oxides such as copper oxide can also be used.

Examples of organic copper salts include carboxyl type, hydroxycarboxylic acid type, amino acid type, alkoxide type, and the like.

The carboxyl type refers to a linear or branched or cyclic saturated or unsaturated hydrocarbon chain with a carbon number of 1 to 20, which is formed by combining a carboxyl group with copper elements. Specific examples include copper acetate and propionic acid. Copper, Copper Butyrate, Copper Valerate, Copper Hexanoate, Copper Heptanoate, Copper Octanoate, Copper Nonanoate, Copper Decanoate, Copper Undecanoate, Copper Dodecanoate, Copper Myristate, Hexadecane Copper heptadecanoate, copper octadecanoate, copper ethylacetoacetate, copper trifluoroacetylacetonate, copper acrylate, copper propiolate, copper methacrylate, copper crotonate, copper isocrotonate, oil Copper ricinate, copper ricinoleate, copper benzoate, copper toluate, copper naphthoate, copper cinnamate, etc. In addition, a polycarboxy group type in which two or more carboxyl groups are bonded to a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain having 1 to 20 carbon atoms can also be exemplified. Examples include copper fumarate, copper maleate, copper phthalate, copper isophthalate, copper terephthalate, copper oxalate, copper malonate, copper succinate, and copper glutarate. , copper adipate, copper pimelate, copper suberate, copper azelate, copper sebacate, etc.

In addition, as a hydroxycarboxylic acid type, the molecule bonded to copper is a linear or branched or cyclic saturated or unsaturated hydrocarbon chain with 1 to 20 carbon atoms having one or more carboxyl groups and one or more hydroxyl groups. Molecules, for example, copper glycolate, copper lactate, copper hydroxymalonate, copper glycerate, copper hydroxybutyrate, copper 2-hydroxybutyrate, copper 3-hydroxybutyrate, copper γ-hydroxybutyrate , Copper Malate, Copper Tartrate, Copper Citrate Malate, Copper Citrate, Copper Isocitrate, Copper Leucine, Copper Mevalonate, Copper Pantoate, Copper Ricinoleate, Copper Reverse Ricinoleate, Brain Copper ketoate, copper quinate, copper gluconate, etc.

In addition, as an amino acid type, the molecule bonded to copper is a molecule having one or more carboxyl groups and one or more amino groups on a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain with 1 to 20 carbon atoms, For example, alanine copper salt, arginine copper salt, asparagine copper salt, aspartate copper salt, cysteine copper salt, glutamine copper salt, glutamate copper salt, glycine copper salt, etc. Salt, Copper Histidine, Copper Isoleucine, Copper Leucine, Copper Lysine, Copper Methionine, Copper Phenylalanine, Copper Proline, Copper Serine, Threonine Copper, tryptophan copper salt, tyrosine copper salt, valine copper salt, etc.

In addition, the alkoxide type is a molecule in which a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain with 1 to 20 carbon atoms is bonded to copper through an oxygen atom, and examples include copper methoxide, Copper ethoxide, copper propoxide, etc.

In addition, examples of other organic copper compounds include cyclooctadiene complexes of copper hexafluoroacetonate and copper (I) hexafluoro-2,4-pentanedione, benzenesulfinic acid hydrate, dimethyl Copper dithiocarbamate, copper tetrafluoroborate, copper trifluoromethanesulfonate, potassium tetrachlorocuprate, etc.

In order to form a copper complex, the molecules of the copper-containing compounds coordinated to the above-mentioned inorganic copper salts and organic copper salts can be roughly classified into inorganic ligands and organic ligands, and examples of inorganic ligands include water , ammonia, carbon monoxide, etc. In addition, as an organic ligand, it refers to an oxygen atom and/or a nitrogen atom that contains one or more and can coordinate with a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain having 1 to 40 carbon atoms. Molecules other than these ligands are not particularly limited as long as they can stabilize the copper-containing compound.

As a particularly preferable copper-containing compound, there can be exemplified compounds having molecules or ions as anions that are decomposed or volatilized at 250° C. or lower by heat treatment after the preparation of copper nitride fine particles, such as copper chloride, copper bromide, sulfuric acid, etc. Copper, Copper Nitrate, Copper Formate, Copper Acetate, Copper Propionate, Copper Butyrate, Copper Valerate, Copper Hexanoate, Copper Heptanoate, Copper Octanoate, Copper Nonanoate, Copper Decanoate, Copper Undecanoate, Copper Undecanoate, Copper Copper alkanoate etc.

Examples of nitrogen sources include compounds containing one or more compounds selected from ammonia gas or ammonium salt compounds, urea, urea derivative compounds, nitrate compounds, amine compounds, and azides.

Ammonium salt compounds include ammonium azide, ammonium benzoate, ammonium chloride, salammoniac, ammonium chlorate, ammonium perchlorate, ammonium permanganate, ammonium chromate, ammonium acetate, nitric acid Ammonium, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, ammonium thioglycolate, ammonium thiocyanate, ammonium bifluoride, ammonium iodide, ammonium iodate, ammonium sulfate, ammonium phosphate, etc. In addition, urea derivatives are compounds in which one or more amino groups in urea are combined with linear or branched or cyclic saturated or unsaturated hydrocarbon chains and aromatic rings having 1 to 20 carbon atoms, and examples include Benzylurea, N-ethyl-N'-phenylurea, o-ethoxyphenylurea, m-ethoxyphenylurea, p-ethoxyphenylurea, N,N'-diphenylurea, N,N '-diphenylurea, tetraphenylurea, N-benzoylurea, etc.

In addition, the amine compound refers to a molecule having a linear or branched or cyclic saturated or unsaturated hydrocarbon chain with 1 to 20 carbon atoms bonded to a 1st to 4th amino group, for example, forma Amine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, cyclohexylamine, 2-methylcyclohexylamine, allylamine, oleylamine, aniline, toluidine , Ethylaniline, etc. In addition, polyamine compounds having two or more primary to quaternary amino groups in the molecule can also be exemplified, and specific examples of diamines include diaminobutane, hexamethylenediamine, trimethylhexamethylene Methyldiamine, m-xylylene lysine diamine, p-phenylenediamine, m-phenylenediamine, toluenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodi Phenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminobiphenyl, 3,3'-dimethyl 4,4'-diaminobiphenyl, 4,4'-diaminobiphenyl Aminodiphenylsulfide, 2,6-diaminonaphthalene, 4,4'-bis(p-aminophenoxy)diphenylsulfone, 4,4'-bis(m-aminophenoxy)diphenylsulfone, 4, 4'-Bis(p-aminophenoxy)benzophenone, 4,4'-bis(m-aminophenoxy)benzophenone, 4,4'-bis(p-aminophenylmercapto)benzophenone Ketones, 4,4'-bis(p-aminophenylmercapto)diphenylsulfone, etc., and specific examples of triamines include 4,4',4"-triaminotriphenylmethane, triamterene, etc. In addition, polyamine compounds can be roughly classified into aliphatic polyamines such as hexamethylenediamine and aromatic polyamines such as p-phenylenediamine.

As an azide, hydrogen azide, sodium azide, etc. are mentioned. A bonded or coordinated nitrogen-containing copper complex can also be used as the copper source and nitrogen source.

Preferable nitrogen-containing compounds include ammonia gas, ammonium chloride, ammonium bromide, ammonium acetate, methylamine, ethylamine, and propylamine, which are decomposed or volatilized at 250°C or lower by heating during the preparation of copper nitride fine particles. , Butylamine, Pentylamine, Hexylamine, Heptylamine, Octylamine, Nonylamine, Decylamine. It is particularly preferable to include ammonia gas which is ammonia volatilized as post-reaction gas, and ammonium salts such as ammonium chloride, ammonium bromide, and ammonium acetate.

As described above, the copper nitride fine particles of the present invention are obtained by dissolving or dispersing a copper source and a nitrogen source, or a copper source, a nitrogen source and a protective agent in a solvent or a dispersion medium, followed by heating.

The solvent is not particularly limited as long as it does not hinder the dispersion of fine particles and has a boiling point of 100°C or higher, preferably 200°C. Organic solvents are preferably used, and examples thereof include alcohol compounds, ether compounds, amine compounds, polyamine compounds, and amino alcohols. compounds, amide compounds, hydrocarbon compounds, etc.

The alcohol compound is a straight-chain or branched or cyclic saturated or unsaturated hydrocarbon chain with 5 to 20 carbon atoms bonded to a hydroxyl group. Specific examples include pentanol, hexanol, and heptanol. Alcohol, octanol, nonanol, decyl alcohol, undecanol, crotyl alcohol, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 6-heptene- 1-alcohol, 7-octen-1-ol, 8-nonen-1-ol, cyclohexanol, cyclohexylmethanol, 4-methylcyclohexanol, phenol, cresol, 4-ethylphenol. In addition, polyhydric alcohol compounds having two or more hydroxyl groups bonded to straight-chain or branched or cyclic saturated or unsaturated hydrocarbon chains with 2 to 10 carbon atoms can also be exemplified, such as ethylene glycol, 1,3 -Propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1, 3-cyclohexanediol, 1,4-cyclohexanediol, 2-butene-1,4-diol, etc.

In addition, as an ether compound, one or more linear, branched, or cyclic saturated or unsaturated hydrocarbon chains having 2 to 10 carbon atoms are cross-linked by one or more oxygen elements. Furthermore, since ether compounds have a low boiling point, one or more hydroxyl groups may be bonded to the hydrocarbon chain in order to obtain the necessary boiling point for synthesis. Specific examples thereof include diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, and diethylene glycol monoethyl ether.

In addition, the amine compound is a compound having one 1st to 4th amino group bonded to a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain having 5 to 20 carbon atoms. Examples thereof include pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, cyclohexylamine, 2-methylcyclohexylamine, allylamine, oleylamine, aniline, toluidine, and ethylaniline. In addition, as a polyvalent amine compound in which two or more amino groups of any one of the first to fourth stages are bonded to a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain having 2 to 10 carbon atoms, examples include: Ethylenediamine, 1,3-diaminopropane, 1,4-diamino-2-methylpropane, 1,4-diaminobutane, 1,5-diaminopentane, hexamethylenebis Amine, 1,7-diaminoheptane, 1,8-diaminooctane, etc.

In addition, examples of amino alcohol compounds include linear, branched, and cyclic saturated or unsaturated hydrocarbon chains R having 5 to 20 carbon atoms in which one or more hydroxyl groups and one or more amino groups are bonded. compound.

As the amide compound, a compound in which a carboxylic acid amide is bonded to a linear or branched or cyclic saturated or unsaturated hydrocarbon chain R having 2 to 20 carbon atoms, the nitrogen of the carboxylic acid amide is Either level 1 or level 2 or level 3 is acceptable.

As the dispersion medium, the above-mentioned solvent can be used, even if it does not dissolve the copper source and the nitrogen source, or the copper source, the nitrogen source and the protective agent, and acts as a dispersant, it can also be prepared by heating for the preparation of copper nitride particles. Comes to function as a solvent.

Examples of the protective agent used in the present invention include alcohol compounds, polyol compounds, amine compounds, polyamine compounds, carboxylic acid compounds, polycarboxylic acid compounds, polymer compounds, and the like. In addition, these can be used in other applications besides the protective agent, the solvent itself can be used as the protective agent, and molecules that can be combined with the above-mentioned copper-containing compound and nitrogen-containing compound can also be used.

As the alcohol compound or polyol compound, ether compound, amine compound, polyamine compound, aminoalcohol compound, amide compound, or hydrocarbon compound used as the protecting agent, one or more of the above-mentioned compounds can be used.

The carboxylic acid compound is a compound in which one carboxyl group is bonded to a linear, branched, or cyclic saturated or unsaturated hydrocarbon chain R having 2 to 20 carbon atoms, and is represented by the chemical structural formula of R-COOH.

As a polycarboxylic acid compound, it is a compound having two or more carboxyl groups bonded to a linear or branched or cyclic saturated or unsaturated hydrocarbon chain R with 2 to 10 carbon atoms, represented by R(-COOH) _n The chemical structural formula shows that it has a value of n=2-8.

The polymer compound has a molecular weight of 1,000 to 100,000, and examples thereof include polyvinylpyrrolidones, polyvinyl alcohols, polyethylene glycols, polyoxyalkylenes, acrylic acid and its esters, methacrylic acid and its esters.

As the protective agent, alcohol compounds, polyol compounds, amine compounds, polyamine compounds, carboxylic acid compounds, polycarboxylic acid compounds, and polymer compounds decomposed or volatilized at 250° C. or less are preferable.

The temperature at which the reaction is carried out in the present invention is preferably 100°C to 250°C, more preferably a temperature range of 150°C to 200°C. If the temperature is low, the copper raw material does not dissolve and the reaction does not proceed. In addition, the upper limit of the reaction temperature is limited by the boiling point of the solvent, and when the temperature is too high, copper nitride is decomposed into copper or copper oxide. As the reaction system, any one of reduced pressure, normal pressure, and increased pressure can be selected as needed. As a reaction system, if it is normal pressure, since an apparatus and process can be simplified, it is preferable.

The heating method is not particularly limited, but electromagnetic waves such as microwaves may be used for heating in order to achieve uniform temperature inside the solution to be heated.

In the method for producing copper nitride fine particles of the present invention, the concentration of the copper-containing compound relative to the organic solvent affects the production efficiency and particle size of the fine particles. If the concentration of the copper-containing compound is too low, the productivity decreases because the concentration of fine particles obtained by the reaction is low. Also, if the concentration of the copper-containing compound is too high, the particle size of the obtained particles becomes too large. Therefore, in the method for producing copper nitride fine particles, the concentration of the copper-containing compound is preferably 0.0001 to 1 mol/L, more preferably 0.001 to 0.1 mol/L in terms of Cu ¹⁺ or Cu ²⁺ .

In the production method of copper nitride fine particles, when ammonia gas is used, the nitrogen source is supplied to the reaction system indefinitely during the reaction, but when a solid or liquid nitrogen source is used, the supply amount of nitrogen becomes limited. The amount of the nitrogen-containing compound added as a nitrogen source is preferably 0.01 to 100 equivalents with respect to the copper concentration. Since unreacted copper ions will exist if the amount of the nitrogen source is small, the yield will decrease, so it is more preferably 0.4 to 100 equivalents. equivalent.

In the method for producing copper nitride fine particles, the amount of the protective agent to be added is 0.01 to 100 equivalents, more preferably 0.1 to 10 equivalents, based on the copper concentration.

The copper nitride fine particles of the present invention, as described above, have a decomposition temperature in the range of 70°C to 300°C in differential thermal balance analysis (atmospheric pressure), accompanied by a decrease in weight (mass). Since the copper nitride fine particles can be wired by printing and have oxidation resistance against air and water, it is possible to provide a material that exhibits conductivity after heat treatment at 300°C or less after wiring is drawn on a thin film by printing or the like. That is, the following advantages can be brought: after the copper nitride particles are used as the ink material for wiring, and the polymer substrate or film is used as the substrate to be printed after coating, when heat treatment is performed, the substrate to be printed can be printed without being affected. Heat-induced damage, eg, processing at temperatures not subject to melting and/or deformation, decomposition, carbonization.

As described above, according to the present invention, it is possible to provide a wiring ink material containing the copper nitride fine particles of the present invention, a substrate to be printed on which the ink material for wiring is coated, and a substrate to be printed by coating the substrate to be printed in 300 The substrate to be printed is heat-treated below ℃, and the metal copper film is formed from copper nitride particles. Coating from the ink material for wiring onto the substrate to be printed can be carried out by a conventional method using an inkjet method, a spray method, an electrostatic spray method, a screen method, a screen printing method, or the like. The metal copper film obtained after the heat treatment exhibits electrical conductivity, but the primary particle diameter of the copper nitride particles used is miniaturized to 50 nm or less, preferably 30 nm or less, more preferably 20 nm or less, and most preferably 10 nm or less. Practical conductivity such as 10 ^-5 Ω.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

Example 1

A 1-octanol solution (50 mL) of copper(II) acetate (0.5 mmol) was prepared in a three-necked flask. While blowing ammonia gas, the solution was heated at a solution temperature of 190° C. for 1 hour using a 230° C. oil bath, and a purple-red precipitate was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The crystal layer analysis (XRD measurement) of the powder was carried out using a powder X-ray diffraction device (M21X from MacSyences Corporation: 40kV, 200mA, CuKα), and a transmission electron microscope (TEM) observation (TECNAI G2 from FEI Corporation, accelerated The voltage is 200kV and the emission current is 8μA).

The particle diameter of the primary particle of the obtained copper nitride fine particle is 10-50 nm, and the particle diameter of a secondary particle is 0.1-0.2 micrometer. For primary particles and secondary particles, image analysis as shown below was performed.

The determination of the primary particles is performed by combining the contrast analysis (Digital Micrograph) of the TEM observation image and the determination by visual observation of the original image. The identification of primary particles by contrast analysis is to extract the part where the contrast difference is within 300, judge the crystal interface from the original image together with this area, and use the minor axis diameter as the particle diameter of primary particles.

The determination of the secondary particles is performed by combining the contrast analysis of the TEM observation image and the visual determination of the original image. Through the contrast analysis, the region where the contrast difference is within 1100 is extracted, and in combination with this, the interface between the particles is visually recognized. The diameter of the major axis of the secondary particles obtained through a series of treatments was taken as the particle diameter of the secondary particles.

Thermal decomposition was measured using a differential thermal balance (Thermo plus EVOⅡ from Rigaku Co., Ltd.: the heating rate is 5°C/min, alumina standard sample, Ar flow, normal pressure or reduced pressure (600Pa)).

FIG. 1 shows the XRD spectrum of the copper nitride particles obtained in Example 1, and the XRD patterns of copper, copper oxide and copper nitride. FIG. 3 shows a TEM observation image of copper nitride fine particles obtained in Example 1. FIG. FIG. 5 shows the results of differential thermal balance analysis (normal pressure and reduced pressure) of the copper nitride fine particles obtained in Example 1. FIG. That is, according to differential thermal balance analysis (normal pressure), it has a thermal decomposition temperature accompanying weight loss at 225° C. or lower.

Example 2

A 1-nonanol solution (50 mL) of copper(II) acetate (0.5 mmol) was prepared in a three-necked flask. While blowing ammonia gas, the solution was heated at a solution temperature of 190° C. for 1 hour using a 230° C. oil bath, and a purple-red precipitate was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle diameter of the primary particle of the obtained copper nitride fine particle was 10-20 nm, and the particle diameter of the secondary particle was 0.1-0.2 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 220° C. or lower.

FIG. 2 shows an XRD spectrum of copper nitride fine particles obtained in Example 2. FIG.

Example 3

A 1-octanol solution (20 mL) of copper(II) octoate (0.28 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 190 degreeC for 1 hour using the 230 degreeC oil bath, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The minor axis diameter of the primary particles of the obtained copper nitride particles is 1 to 5 nm, the major axis diameter is 50 to 100 nm, and the particle diameter of the secondary particles is 0.1 to 0.5 μm. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles show a phenomenon of weight loss accompanying thermal decomposition of octanoic acid and copper nitride present on the surface at temperatures below about 220°C.

FIG. 2 shows the XRD spectrum of the copper nitride fine particles obtained in Example 3. FIG. FIG. 4 shows a TEM observation image of copper nitride fine particles obtained in Example 3. FIG.

Example 4

A 1-octanol solution (20 mL) of copper(II) octoate (0.28 mmol) and nonylamine (1 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 190 degreeC for 1 hour using the 230 degreeC oil bath, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle diameter of the primary particle of the obtained copper nitride fine particle was 20-30 nm, and the particle diameter of the secondary particle was 0.2-0.5 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 250° C. or lower.

Example 5

A 1-octanol solution (20 mL) of copper(II) myristate (0.28 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 190 degreeC for 1 hour using the 230 degreeC oil bath, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The obtained copper nitride microparticles are needle-shaped crystals with primary particles having a short-axis diameter of 5-10 nm and a long-axis diameter of 50-100 nm, and secondary particles having a particle diameter of 0.1-0.2 μm. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 250° C. or lower.

Example 6

A 1-octanol solution (20 mL) of copper(II) laurate (0.28 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 190 degreeC for 1 hour using the 230 degreeC oil bath, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The obtained copper nitride microparticles are needle-shaped crystals with primary particles having a minor axis diameter of 5 to 10 nm and a major axis diameter of 50 to 100 nm, and secondary particles having a particle diameter of 0.1 to 0.15 μm. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 300° C. or lower.

Example 7

A dodecane solution (20 mL) of copper (II) octoate (0.28 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 190 degreeC for 1 hour using the oil bath of 230 degreeC, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle diameter of the primary particle of the obtained copper nitride fine particle is 10-50 nm, and the particle diameter of a secondary particle is 0.1-0.3 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 240° C. or lower.

Example 8

A 1-octanol solution (10 mL) of ammonia copper (II) azide (0.1 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 180 degreeC for 1 hour using the oil bath of 220 degreeC, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle diameter of the primary particle of the obtained copper nitride fine particle is 50-100 nm, and the particle diameter of a secondary particle is 0.1-0.5 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles had a thermal decomposition temperature accompanying weight loss at 221° C. or lower.

FIG. 2 shows an XRD spectrum of copper nitride fine particles obtained in Example 8. FIG.

Example 9

A 1-octanol solution (10 mL) of ammonia copper (II) azide (0.2 mmol) and hexylamine (1 mmol) was prepared in a three-necked flask. While blowing ammonia gas, it heated at 180 degreeC for 1 hour using the oil bath of 220 degreeC, and the black deposit was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle size of the primary particle of the obtained copper nitride fine particle was 50-100 nm, and the particle size of the secondary particle was 0.2-0.5 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 250° C. or lower.

Example 10

A 1-nonanol solution (50 mL) of copper(II) acetate (0.5 mmol) and ammonium acetate (5 mmol) was prepared in a three-necked flask. While blowing nitrogen gas, the solution was heated at a solution temperature of 190° C. for 1 hour using a 230° C. oil bath, and a purple-red precipitate was confirmed. This precipitate was filtered by centrifugation, washed several times with n-hexane, and vacuum-dried. The powder was measured by XRD and observed by TEM.

The particle diameter of the primary particle of the obtained copper nitride fine particle is 10-50 nm, and the particle diameter of a secondary particle is 0.1-0.5 micrometer. According to differential thermal balance analysis (atmospheric pressure), the obtained copper nitride fine particles have a thermal decomposition temperature accompanied by weight loss at 250° C. or lower.

Table 1 shows the synthesis conditions of the examples, that is, the combination of copper source, nitrogen source, protective agent, and solvent, and the XRD analysis results of the obtained precipitate.

Table 1

Industrial Utilization Possibility

The present invention provides copper nitride having a decomposition temperature of 300°C or lower, and provides a material capable of providing metallic copper by heating at 300°C or lower. It is expected to be used, for example, as an ink material for wiring of printed electronic devices.

Claims (16)

1. Copper nitride microparticles having a primary particle diameter of 1 to 100 nm and a decomposition temperature of 300° C. or lower. 2. The copper nitride fine particles according to claim 1, wherein the particle size of the secondary particles is 1 μm or less. 3. The copper nitride fine particles according to claim 1 or 2, which have a decomposition temperature accompanied by weight loss in the range of 70°C to 300°C in differential thermal balance analysis. 4. The copper nitride fine particles according to any one of claims 1 to 3, wherein the secondary particles are spherical in electron microscope observation. 5. The copper nitride particles according to any one of claims 1 to 4, in powder X-ray diffraction, 21.5 to 24.5°, 31.0 to 34.0°, 39.0 to 42.0° and 46.0 to 49.0° under the CuKα line There is at least one diffraction peak derived from copper nitride in any one of the regions. 6. A method of manufacturing copper nitride particles, characterized in that, source of copper and nitrogen, or Copper source, nitrogen source and protective agent The copper nitride fine particles according to any one of claims 1 to 5 are produced by dissolving or dispersing in a solvent or a dispersion medium, and then heating. 7. The method for producing copper nitride fine particles according to claim 6, wherein the copper source contains one or more selected from inorganic copper salts, organic copper salts, and copper complexes. 8. The method for producing copper nitride particles according to claim 6 or 7, wherein the nitrogen source comprises ammonia or ammonium salt compounds, urea, urea derivative compounds, nitrate compounds, amine compounds and azide compounds more than one of them. 9. The method for producing copper nitride fine particles according to any one of claims 6 to 8, wherein the copper source and the nitrogen source are bonded or coordinated to form a nitrogen-containing copper complex. 10. The method for producing copper nitride fine particles according to any one of claims 6 to 9, wherein the protective agent is a compound having one or more carboxyl groups, amino groups and/or hydroxyl groups. 11. The method for producing copper nitride fine particles according to any one of claims 6 to 10, wherein the solvent is an organic solvent having a boiling point of 100° C. or higher. 12. The method for producing copper nitride fine particles according to any one of claims 6 to 11, wherein the heating temperature is 100 to 250°C. 13. The method for producing copper nitride microparticles according to any one of claims 6 to 11, wherein the concentration of the copper source relative to the solvent is 0.0001 to 1 mol/L in terms of the concentration converted to Cu ¹⁺ or Cu ²⁺ . 14. An ink material for wiring comprising the copper nitride fine particles according to claim 1. 15. A substrate to be printed coated with the ink material for wiring according to claim 14. 16. A printed substrate obtained by heating the printed substrate according to claim 15 to form a metallic copper film from copper nitride fine particles.