JP2016145299A - Conductive material and conductor using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive material capable of providing conducting substance at a low temperature and a conductor produced with the conductive material obtained by the present invention.SOLUTION: There is provided a conductive material containing a copper containing particle in which alkylamine is used as a protecting agent, organic solvent and fatty acid A. It is preferable that the fatty acid A contains at least one fatty acid having 9 or less of carbon atoms. It is preferable that the fatty acid A is contained at 0.01 to 40.0 parts by mass relatively to 100 parts by mass of the copper containing particle. It is preferable that the copper containing particle in which alkylamine is used as a protecting agent is one obtained by a step of heating a mixture of a salt compound of fatty acid B and copper (fatty acid copper), a reducing compound and alkylamine. It is preferable that the reducing compound comprises at least one compound selected from a group consisting of hydrazine, hydrazine derivative, hydroxylamine and hydroxylamine derivative. There is also provided a conductor obtained by heating the conductive material at 250°C or less.SELECTED DRAWING: None

Description

  The present invention relates to a conductive material and a conductor using the same.

  As a method for forming a metal pattern, a step of applying a conductive material such as ink or paste containing metal particles such as copper onto a substrate by ink jet printing, screen printing, etc., and heating the conductive material to sinter the metal particles In addition, a method including a conductor-forming step for developing conductivity is known. As the metal particles contained in the conductive material, those in which an organic substance as a protective agent is attached to the surface in order to suppress the oxidation of the metal and enhance the storage stability are known.

  Patent Document 1 describes a coated copper particle that can be sintered at a low temperature and exhibits good conductivity and a method for producing the same. The copper particles described in Patent Document 1 are obtained by mixing a copper precursor such as copper oxalate and a reducing compound such as hydrazine to obtain a composite compound, and heating the composite compound in the presence of an alkylamine. It is manufactured by the method which has these. In the example of Patent Document 1, the ink containing the produced copper particles is heated to 300 ° C. at 60 ° C./min in an argon atmosphere and held for 30 minutes to achieve a conductor.

JP 2012-72418 A

  In order to suppress the metal oxidation and increase the storage stability, the metal particles have a protective agent attached to the surface. However, in order to develop conductivity, it is necessary to sinter the particles by removing the protective agent from the metal particles in the conductorization step so that the metal surface is exposed. Currently, a problem is that a high temperature is required when the protective agent is desorbed from the metal particles.

In recent years, from the viewpoints of improving production efficiency and diversifying the types of base materials to be used, development of a technology that enables metal particles to be made conductive at a lower temperature (for example, 150 ° C. or lower) has been demanded. Accordingly, there is a need for the development of a conductorization method that can be performed at a temperature lower than the temperature described in Patent Document 1.
In order to solve the above-described problems, an object of the present invention is to provide a conductive material capable of obtaining a conductor at a low temperature and a conductor manufactured using the conductive material obtained in the present invention.

  The conductive material of the present invention is obtained by mixing copper-containing particles having an alkylamine as a protective agent with an organic solvent and further adding a fatty acid. As a result, fatty acids are added to the alkylamine adhering to the particles, the bond strength between the alkylamine and the particles is weakened, and a conductor can be formed at a low temperature.

The present invention relates to [1] a conductive material containing copper-containing particles having an alkylamine as a protective agent, an organic solvent, and fatty acid A.
The present invention also relates to [2] the conductive material according to the above [1], wherein the fatty acid A contains at least one fatty acid having 9 or less carbon atoms.
Moreover, this invention relates to the electrically-conductive material as described in said [1] or [2] which contains 0.01-40.0 mass parts of [3] the said fatty acid A with respect to 100 mass parts of copper containing particles.
Moreover, this invention has the process in which the copper containing particle | grains which use [4] the said alkylamine as a protecting agent heat the mixture of the fatty acid B and the salt compound (fatty acid copper) of copper, a reducing compound, and an alkylamine. It relates to the conductive material according to any one of [1] to [3] obtained above.
The present invention also relates to [5] the conductive material according to the above [4], wherein the fatty acid B contains at least one fatty acid having 9 or less carbon atoms.
Further, the present invention provides [6] The conductive material according to [4] or [5], wherein the reducing compound includes at least one selected from the group consisting of hydrazine, hydrazine derivatives, hydroxylamine, and hydroxylamine derivatives. Regarding materials.
Moreover, this invention relates to the conductor obtained by heating the conductive material as described in any one of [7] said [1]-[6] at 250 degrees C or less.

This invention can provide the electroconductive material which can be manufactured at low temperature, and the conductor which can be manufactured at low temperature by containing the copper containing particle | grains which use alkylamine as a protective agent, the organic solvent, and the fatty acid A.
Moreover, the volatility of the fatty acid A at the time of conductorization can be adjusted by changing the carbon number of the fatty acid A.
Moreover, the ease of removal | elimination of a protective agent can be adjusted by changing the compounding quantity of the fatty acid A with respect to the copper containing particle | grains which use an alkylamine as a protective agent.

<Conductive material>
The electrically conductive material of this invention contains the copper containing particle | grains in which the alkylamine which is organic substance exists in at least one part of the surface, the organic solvent, and the fatty acid A.

<Fatty acid A>
Fatty acid A used in the present invention can be added to alkylamine, which is a protective agent for the surface of the copper-containing particles, to weaken the bonding force between the copper-containing particles and the alkylamine and to be easily detached even at low temperatures. The fatty acid A may be only one type or two or more types.

  The fatty acid A is a carboxylic acid represented by RCOOH. R is a hydrocarbon group, which may be a saturated fatty acid or an unsaturated fatty acid, and may be linear or branched. The fatty acid A used in the present invention is preferably a branched fatty acid having a low boiling point so that the amount remaining in the conductor is reduced from the viewpoint of obtaining good conductivity at low temperature.

  The fatty acid A is preferably a fatty acid having 9 or less carbon atoms. Examples of saturated fatty acids having 9 or less carbon atoms include acetic acid (2 carbon atoms), propionic acid (3 carbon atoms), butyric acid and isobutyric acid (4 carbon atoms), valeric acid and isovaleric acid (5 carbon atoms), capron Examples include acids and isocaproic acid (6 carbon atoms), enanthic acid and isoenanthic acid (7 carbon atoms), caprylic acid and isocaprilic acid, isocaproic acid (8 carbon atoms), nonanoic acid and isononanoic acid (9 carbon atoms). it can. From the viewpoint of obtaining good conductivity, a fatty acid having 6 or less carbon atoms, which is a low boiling fatty acid, is preferred. A fatty acid having 2 or less carbon atoms is more preferred. Examples of the unsaturated fatty acid having 9 or less carbon atoms include those having one or more double bonds in the hydrocarbon group of the saturated fatty acid.

  The fatty acid A is 0.01 to 40.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. The larger the amount of fatty acid A, the easier it is to desorb alkylamine from the copper-containing particles. However, when the amount is too large, fatty acid A remains in the conductor and good conductivity cannot be obtained. Therefore, although depending on the structure of fatty acid A and the conductorization temperature, the fatty acid A is more preferably 1 to 30.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. In the case of fatty acids such as nonanoic acid having a high carbon number and a high boiling point, 1 to 20.0 parts by mass are preferred.

<Copper-containing particles using alkylamine as protective agent>
The copper containing particle | grains which use the alkylamine used as a protective agent for this invention contain the substance derived from alkylamine or an alkylamine in at least one part of the particle | grain surface containing copper. By changing the carbon number of the alkylamine, it is possible to adjust the particle size and shape of the obtained copper-containing particles, the dispersibility of the particles in the solvent, the suppression of oxidation of the metal particles, and the ease of desorption of the protective agent.

In the present invention, the alkylamine is a primary amine represented by RNH ₂ (R is a hydrocarbon group and may be cyclic or branched), and R ¹ R ² NH (R ¹ and R ² are the same). Or a different amine group, which may be cyclic or branched, and a diamine having two amino groups substituted on the hydrocarbon chain. The alkylamine may have one or more double bonds, and may have atoms such as oxygen, silicon, nitrogen, sulfur, and phosphorus. The alkylamine may be only one type or two or more types.

  The hydrocarbon group of the alkylamine preferably has 7 or less carbon atoms. When the hydrocarbon group of the alkylamine has 7 or less carbon atoms, the molecular weight is small, and it is easy to desorb at a low boiling point. Therefore, good conductorization tends to be achieved when heated in the conductorization step. From the viewpoint of achieving better conductorization, the hydrocarbon group of the alkylamine preferably has 6 or less carbon atoms. However, when the carbon number of the hydrocarbon group of the alkylamine is 3 or less, the carbon group is more preferably in the range of 4 to 6 because it is easily detached and the storage stability of the copper particles is deteriorated.

  Specific examples of the primary amine used in the method of the present invention include methylamine, ethylamine, 2-ethoxyethylamine, propylamine, isopropylamine, butylamine, isobutylamine, pentylamine, isopentylamine, hexylamine, and cyclohexylamine. , Heptylamine, octylamine, nonylamine, decylamine, dodecylamine, 3-hydroxypropylamine, 3-methoxypropylamine, 3-ethoxypropylamine and the like.

  Specific examples of the secondary amine used in the method of the present invention include dimethylamine, ethylmethylamine, diethylamine, ethylpropylamine, dipropylamine, diisopropylamine, dibutylamine, ethylpropylamine, ethylpentylamine, dibutylamine. , Dipentylamine, dihexylamine and the like.

  Specific examples of the diamine used in the method of the present invention include ethylenediamine, N, N-dimethylethylenediamine, N, N′-dimethylethylenediamine, N, N-diethylethylenediamine, N, N′-diethylethylenediamine, 1,3. -Propanediamine, 2,2-dimethyl-1,3-propanediamine, N, N-dimethyl-1,3-diaminopropane, N, N'-dimethyl-1,3-diaminopropane, N, N-diethyl- 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diamino-2-methylpentane, 1,6-diaminohexane, N, N′-dimethyl-1,6-diaminohexane, 1, Examples include 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,12-diaminododecane, and the like. .

  The organic substance (alkylamine, fatty acid A, etc.) present on at least a part of the surface of the copper-containing particle is preferably 0.1 to 20 parts by mass with respect to the total of the metal particles and the organic substance. When the ratio of the organic substance is 0.1 parts by mass or more, sufficient oxidation resistance tends to be obtained. When the proportion of the organic substance is 20 parts by mass or less, conductorization at a low temperature tends to be easily achieved. As for the ratio of the organic substance with respect to the sum total of a metal particle and organic substance, it is more preferable that it is 0.3-10 mass parts, and it is still more preferable that it is 0.5-5 mass parts.

  The particle size of the copper-containing particles used in the present invention is not particularly limited, but can be selected according to the application. The smaller the particle size, the higher the surface energy, and the easier it is to sinter even when heated at low temperature, so that the median major axis length of 200 copper-containing particles selected at random is generally 1 to 1. A range of 500 nm is preferable. The smaller the particle size, the easier it is to conduct at a low temperature. However, if the particle size is too small, the particles are easily oxidized and the storage stability is deteriorated. In order to facilitate sintering while suppressing the oxidation of the particles, a particle size of 10 to 300 nm is more preferable.

The shape of the copper-containing particles used in the present invention is not particularly limited, and examples thereof include a spherical shape, a long granular shape, a disc shape, a plate shape, and a fiber shape. The shape can be selected in accordance with the use of the copper-containing particles, and from the viewpoint of conductivity, a disk shape or a plate shape in which the contact surface between the particles is large and conductivity is easily obtained is preferable. From the viewpoint of printability of the conductive material, it is preferably spherical or long granular.
In the present invention, the length of the major axis means the distance between two planes selected so that the distance between the two planes circumscribing the particle and parallel to each other is maximized. In the present invention, the median value of the length of the major axis means the average value of the lengths of the major axes of 200 copper-containing particles, and the median when the values of the major axis lengths are arranged in ascending order. Means the arithmetic average value of the two values (100th and 101st) located at. The length of the major axis of the copper-containing particles can be measured by a usual method such as observation with an electron microscope.

  The copper-containing particles used in the present invention contain at least metallic copper, and may contain other substances as necessary. Besides metallic copper, copper compounds such as fatty acid copper, copper oxide, and copper chloride may be contained within a range that does not adversely affect conductivity. Examples of substances other than copper include metals such as gold, silver, platinum, tin, nickel, zinc, and titanium, and compounds containing these metal elements. From the viewpoint of forming a copper pattern with excellent conductivity, the content of copper metal in the copper-containing particles is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and 70 parts by mass or more. More preferably it is.

<Fatty acid B>
The method for producing a copper-containing particle using an alkylamine as a protective agent for use in the present invention comprises a step of heating a salt compound (fatty acid copper) comprising a fatty acid B and copper, a reducing compound, and a mixture containing the alkylamine. Manufactured by.

  The method uses a salt compound comprising fatty acid B and copper as the copper particle raw material. Thereby, compared with the method of patent document 1 which uses copper oxalate etc. as a copper particle raw material, without using the fatty acid B, the particle size of the copper containing particle | grains obtained by changing the carbon number of the fatty acid B, and The shape, the dispersibility of the particles in the solvent, the suppression of the oxidation of the metal particles, and the ease of desorption of the protective agent can be adjusted.

  The fatty acid B is a carboxylic acid represented by RCOOH (R is a hydrocarbon group, which may be linear or branched). The fatty acid B used in the present invention may be a saturated fatty acid or an unsaturated fatty acid. From the viewpoint of oxidation prevention by good coating of particles and dispersion of particles in an organic solvent, linear saturated fatty acids are preferred. From the viewpoint of low-temperature conductorization, branched saturated fatty acids are preferred because of their low boiling points. Only one type or two or more types of fatty acids may be used.

  The fatty acid B preferably has 9 or less carbon atoms. Examples of saturated fatty acids having 9 or less carbon atoms include acetic acid (2 carbon atoms), propionic acid (3 carbon atoms), butyric acid and isobutyric acid (4 carbon atoms), valeric acid and isovaleric acid (5 carbon atoms), capron Examples include acids (carbon number 6), enanthic acid and isoenanthic acid (carbon number 7), caprylic acid, isocaprilic acid and isocaproic acid (carbon number 8), nonanoic acid and isononanoic acid (carbon number 9). Examples of the unsaturated fatty acid having 9 or less carbon atoms include those having one or more double bonds in the hydrocarbon group of the saturated fatty acid.

  The said fatty acid B used for manufacture of copper containing particle | grains can affect properties, such as the dispersibility to the dispersion medium of the copper containing particle | grains obtained, and sinterability. For this reason, it is preferable to select the kind of fatty acid according to the use of copper-containing particles. From the viewpoint of homogenizing the particle shape, it is preferable to use a fatty acid having 9 or less carbon atoms and a fatty acid having 4 or less carbon atoms in combination. For example, nonanoic acid having 9 carbon atoms and acetic acid having 2 carbon atoms are preferably used in combination. The ratio in particular when using together the fatty acid having 9 or less carbon atoms and the fatty acid having 4 or less carbon atoms is not limited.

  The method for obtaining the salt compound of fatty acid B and copper (fatty acid copper) is not particularly limited. For example, it may be obtained by mixing copper hydroxide and a fatty acid in a solvent, or commercially available fatty acid copper may be used. Alternatively, by mixing copper hydroxide, a fatty acid and a reducing compound in a solvent, the formation of fatty acid copper and the formation of a complex formed between the fatty acid copper and the reducing compound are performed in the same process. Also good.

<Reducing compound>
As a group consisting of hydrazine, hydrazine derivatives, hydroxylamine and hydroxylamine derivatives which are reducing compounds used in the method for producing copper-containing particles, specifically, hydrazine derivatives including hydrazine and methylhydrazine, hydrazine hydrochloride, sulfuric acid Examples include hydrazine compounds such as hydrazine and hydrazine hydrate, hydroxylamine derivatives such as hydroxylamine and methylhydroxylamine, sodium compounds such as sodium borohydride, sodium sulfite, sodium bisulfite, sodium thiosulfate, and sodium hypophosphite. be able to. From the viewpoint of the purity of the copper-containing particles to be produced, a reducing compound such as hydrazine or methylhydrazine in which the by-product generated in the reduction reaction is easily separated such as nitrogen and methane is preferable. A reducing compound may be used individually by 1 type, or may use 2 or more types together.

  By selecting a suitable one from hydrazine or hydroxylamine derivatives, the reactivity with fatty acid copper can be changed, and the particle size and particle size distribution of the copper-containing particles can be adjusted. Examples of hydrazine derivatives include methyl hydrazine, ethyl hydrazine, n-propyl hydrazine, isopropyl hydrazine, n-butyl hydrazine, isobutyl hydrazine, sec-butyl hydrazine, t-butyl hydrazine, n-pentyl hydrazine, isopentyl hydrazine, and neo-pentyl hydrazine. , T-pentylhydrazine, n-hexylhydrazine, isohexylhydrazine, n-heptylhydrazine, n-octylhydrazine, n-nonylhydrazine, n-decylhydrazine, n-undecylhydrazine, n-dodecylhydrazine, cyclohexylhydrazine, phenyl Examples include hydrazine, 4-methylphenylhydrazine, benzylhydrazine, 2-phenylethylhydrazine, 2-hydrazinoethanol, and acetohydrazine. Rukoto can. Examples of hydroxylamine derivatives include N, N-di (sulfoethyl) hydroxylamine, monomethylhydroxylamine, dimethylhydroxylamine, monoethylhydroxylamine, diethylhydroxylamine, N, N-di (carboxyethyl) hydroxylamine and the like. Can do.

  The ratio of the copper and the reducing compound contained in the copper salt compound (fatty acid copper) is not particularly limited as long as a desired complex is formed. For example, the ratio (copper: reducing compound) can be in the range of 1: 1 to 1: 4 on a molar basis, preferably in the range of 1: 1 to 1: 3, and 1: 1 to 1 : The range of 2 is more preferable.

<Method for producing copper-containing particles using alkylamine as protective agent>
In the said method, the method in particular for implementing the process of heating the composition containing a copper salt compound (fatty acid copper), a reducing compound, and an alkylamine is not restrict | limited. For example, a method in which fatty acid copper and a reducing compound are mixed in a solvent and then heated by adding an alkylamine, a method in which fatty acid copper and an alkylamine are mixed with a solvent, and then a method in which a reducing compound is further added and heated, a fatty acid A method of heating copper hydroxide, a fatty acid, a reducing compound, and an alkylamine, which are copper starting materials, in a solvent, a method of heating, a method of mixing a fatty acid copper and an alkylamine in a solvent, and then adding a reducing compound and heating Etc.

  The composition containing fatty acid copper, a reducing compound and an alkylamine may further contain a solvent. From the viewpoint of promoting the formation of a complex of fatty acid copper and a reducing compound, it is preferable to include a polar solvent. Here, the polar solvent is preferably one that dissolves in water at 25 ° C., and more preferably an alcohol solvent. The reason why the formation of the complex is promoted by using alcohol as the solvent is not clear, but it is considered that the contact with the water-soluble reducing compound is promoted while dissolving the solid fatty acid copper. The solvent may be used alone or in combination of two or more.

  Specific examples of the alcohol used as the solvent include 1-propanol, 2-propanol, butanol, pentanol, and hexanol. Among these, 1-propanol and 2-propanol having strong polarity are more preferable. Methanol, ethanol, and the like are not preferable because the copper-containing particles generated due to too strong polarity are oxidized.

<Conductive material (ink or paste composition)>
The conductive material of the present invention includes a conductive ink or a conductive paste obtained by mixing copper-containing particles having an alkylamine as a protective agent, an organic solvent, and a fatty acid A. If necessary, a dispersion stabilizer that keeps the particles dispersed and other components may be included. By making ink or paste, various printing methods can be supported.

  The organic solvent used in forming the ink or paste in the present invention is not particularly limited, and can be selected from organic solvents generally used for producing a conductive ink, a conductive paste and the like according to the use. For example, terpineol, isobornylcyclohexanol, dihydroterpineol, dihydroterpineol acetate and the like are preferable from the viewpoint of viscosity control.

  The state of the conductive material of the present invention is not particularly limited and can be selected according to the application. For example, when the conductive material is applied to the screen printing method, it is preferably a conductive ink having a viscosity of 0.1 to 30 Pa · s, more preferably 1 to 30 Pa · s at the temperature used. When the conductive material is applied to the ink jet printing method, it is preferably a conductive ink having a viscosity of 0.1 to 30 mPa · s, more preferably 5 to 20 mPa · s at the temperature used. When adjusting the viscosity, it can be controlled by the viscosity of the organic solvent used, the concentration of the conductive material, or the like.

<Conductivity>
In the present invention, “conducting” means that the metal-containing particles are sintered to be changed into a conductive object. In the method for converting the conductive material of the present invention into a conductor, the components in the atmosphere in which the heating step is carried out are not particularly limited, and can be selected from nitrogen, argon, and the like used in a normal conductor manufacturing step.

  In the method for converting a conductive material of the present invention into a conductor, a conductor can be obtained by heating at 250 ° C. or lower. Preferably it is 200 degrees C or less, More preferably, it is 150 degrees C or less. The heating process may be performed at a constant rate of temperature rise or may be changed irregularly. The time for the heating step is not particularly limited, and can be selected in consideration of the heating temperature, the heating atmosphere, the amount of copper-containing particles, and the like. Fatty acid A is added to the alkylamine that protects the copper-containing particles by this heating, and the binding force between the alkylamine and the particles becomes weak and easily detached, and the surface of the copper-containing particles is exposed and the particles are sintered together. A conductor is formed.

  When the conductive material of the present invention is made into a conductor, steps other than heating may be included or used as necessary. As other processes, before heating, during heating, or any process after heating, heating in a reducing atmosphere to reduce copper-containing particles or copper oxide in the conductor, removing organic components by light firing A process, a process of applying a load, etc. can be mentioned.

  The base material in particular when making into a conductor is not restrict | limited, It does not need to have even if it has electroconductivity. For example, metals such as Cu, Au, Pt, Pd, Ag, Zn, Ni, Co, Fe, Al, Sn, alloys of these metals, semiconductors such as ITO, ZnO, SnO, Si, glass, graphite, graphite, etc. A carbon material, resin, paper, etc. can be mentioned. Since the conductive material of the present invention can be obtained by heating at a low temperature, it can be suitably applied particularly when a substrate made of a material having relatively low heat resistance is used. An example of such a material is a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate, and polyimide resins. The shape of the substrate is not particularly limited, and may be a plate shape, a rod shape, a roll shape, a film shape, or the like.

<Conductor>
The “conductor” refers to an object having conductivity. The shape of the conductor produced by the conductive material (conductive ink / paste) of the present invention is not particularly limited, and examples thereof include a thin film shape and a pattern shape. The conductor manufactured by the conductive material of the present invention can be used for wiring of various electronic parts, heat conduction paths, and the like. In particular, since a conductor manufactured using the conductive material of the present invention can be manufactured at a low temperature, it is suitably used for applications in which a metal foil, a wiring pattern, or the like is formed on a substrate having low heat resistance such as a resin. In addition to the formation of wiring patterns, it is also suitably used for applications as a conductive adhesive between metal surfaces.

  The wiring and heat conduction paths of electronic parts in which the conductor of the present invention is used can be used in various devices. It is suitably used for wiring boards, displays, sensors, lighting, and solar cell applications. In particular, since the conductor manufactured using the conductive material of the present invention can be manufactured at a low temperature, it is preferably used for flexible devices such as flexible displays and flexible sensors with low heat resistance.

  Hereinafter, although the conductive material and the conductor of the present invention will be described based on examples, the present invention is not limited to these examples.

<Example 1>
[1.1] Synthesis of copper nonanoate To 91.5 g (0.94 mol) of copper hydroxide (Kanto Chemical Co., Ltd., special grade), 150 mL of 1-propanol (Kanto Chemical Co., Ltd., special grade) was added and stirred. 370.9 g (2.34 mol) of nonanoic acid (Kanto Chemical Co., Inc., purity 90 mass% or more) was added. The obtained mixture was heated and stirred at 90 ° C. for 30 minutes in a separable flask. The obtained solution was filtered while heated to remove undissolved substances. Thereafter, the mixture was allowed to cool, and the produced copper nonanoate was suction filtered and washed with hexane until the washing liquid became transparent. The obtained powder was dried in an explosion-proof oven at 50 ° C. for 3 hours to obtain copper (II) nonanoate. The yield was 340 g (yield 96 mass%).

[1.2] Synthesis of copper particles 60.02 g (0.159 mol) of nonanoate copper (II) obtained above and copper (II) acetate anhydride (Kanto Chemical Co., Ltd., special grade) 28.84 g (0. 159 mol) was put into a separable flask, and 150 mL of 1-propanol and 131.17 g (1.28 mol) of hexylamine (Tokyo Chemical Industry Co., Ltd., purity 99 mass%) were added and dissolved. After transferring to an ice bath and cooling to an internal temperature of 5 ° C., 31.79 g (0.64 mol) of hydrazine monohydrate (Kanto Chemical Co., Ltd., special grade) was added to the solution of fatty acid copper, and in the ice bath. Stir. The molar ratio of copper: hexylamine is 1: 4. Subsequently, it heated and stirred at 125 degreeC in the oil bath. At that time, the reduction reaction accompanied with foaming proceeded, and the reaction was completed within 20 minutes. The inner wall of the separable flask had a copper luster and the solution turned dark red. Centrifugation was performed at 9000 min ⁻¹ (rotation / min) for 10 minutes to obtain a solid material. The step of further washing the solid with 400 mL of hexane was repeated three times to remove the acid residue, thereby obtaining a copper cake containing copper powder powder having copper luster.

  The copper cake (50 parts by mass), terpineol (25 parts by mass) as an organic solvent, and isobornylcyclohexanol (trade name: Tersolve MTPH, Nippon Terpene Chemical Co., Ltd.) (25 parts by mass), the copper cake as a fatty acid A Acetic acid (20 parts by mass) was mixed with 100 parts by mass to prepare a conductive paste. The obtained conductive paste was applied onto a polyethylene naphthalate (PEN) film and heated to form a thin film of metallic copper. Heating was carried out by holding at 140 ° C. for 60 minutes in an oven having an atmosphere with an oxygen concentration of 0.0 ppm at a pressure of 500 Pa nitrogen.

<Example 2>
The same operation as in Example 1 was carried out except that acetic acid (5 parts by mass) was mixed with 100 parts by mass of the copper cake.

<Example 3>
It implemented like Example 1 except having mixed nonanoic acid (20 mass parts) instead of acetic acid.

<Example 4>
It implemented like Example 1 except having heated at 200 degreeC at the time of conductorization.

<Example 5>
It implemented like Example 1 except having heated at 200 degreeC at the time of conductorization.

<Comparative Example 1>
The same procedure as in Example 1 was performed except that acetic acid was not mixed.

<Comparative example 2>
It carried out similarly to the comparative example 1 except having heated at 200 degreeC at the time of conductorization.

<Evaluation>
The surface resistivity measured by a four-end needle surface resistance measuring instrument and the volume resistivity of the metallic copper thin film obtained in each example and each comparative example, and a non-contact surface / layer cross-sectional shape measurement system (VertScan, Inc.) Tables 1 to 3 show the results calculated from the film thickness obtained by Ryoka System.

脂肪酸Ａとして酢酸を使用した本発明の導電材料は１４０℃の低温処理でも良好な導電性を発現し、添加量が多いほど良好な導電性を得られる傾向を示した。

The conductive material of the present invention using acetic acid as the fatty acid A exhibited good conductivity even at a low temperature treatment of 140 ° C., and showed a tendency to obtain better conductivity as the addition amount increased.

表２より、脂肪酸Ａとして炭素数の多いノナン酸を使用した本発明の導電材料は１４０℃の低温導体化では良好な導電性を発現しなかった（実施例３）。しかし、表３に示したように、２００℃の比較的低温の導体化であれば炭素数が多いノナン酸でも導電性を良好にすることが分かった。
以上より本発明の導電材料によって低温の導体化で良好な導電性を発現することが判明した。

From Table 2, the conductive material of the present invention using nonanoic acid having a large number of carbon atoms as the fatty acid A did not exhibit good conductivity when made into a low-temperature conductor at 140 ° C. (Example 3). However, as shown in Table 3, it was found that if the conductor was made at a relatively low temperature of 200 ° C., even nonanoic acid having a large number of carbon atoms would improve conductivity.
From the above, it has been found that the conductive material of the present invention exhibits good conductivity at low temperature.

Claims (7)

  A conductive material containing copper-containing particles having an alkylamine as a protective agent, an organic solvent, and fatty acid A.   The conductive material according to claim 1, wherein the fatty acid A contains at least one fatty acid having 9 or less carbon atoms.   The conductive material according to claim 1, wherein the fatty acid A is contained in an amount of 0.01 to 40.0 parts by mass with respect to 100 parts by mass of the copper-containing particles.   The copper-containing particle | grains which use the said alkylamine as a protective agent are obtained by having the process of heating the mixture of the fatty acid B and the copper salt compound (fatty acid copper), a reducing compound, and an alkylamine. The conductive material according to any one of the above.   The conductive material according to claim 4, wherein the fatty acid B contains at least one fatty acid having 9 or less carbon atoms.   The conductive material according to claim 4 or 5, wherein the reducing compound includes at least one selected from the group consisting of hydrazine, hydrazine derivatives, hydroxylamine, and hydroxylamine derivatives.   The conductor obtained by heating the electrically-conductive material as described in any one of Claims 1-6 at 250 degrees C or less.