JP2016146290A - Conductive composition, conductive material and conductor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive composition capable of obtaining a conductor (conductive substance) by an active ray irradiation process, conductive material using it and a conductor.SOLUTION: There is provided a conductive composition consisting of a copper containing particle obtained by a step of heating a mixture of a salt compound of fatty acid and copper (fatty acid copper), a reducing compound and alkylamine, and a photo degradable compound. It is preferable that the photo degradable compound is a photo polymerization initiator and of 0.02 to 5.0 parts by mass relatively to 100 parts by mass of the copper containing particle. There is also provided conductive material (conductive paste, conductive ink) obtained by mixing the conductive composition with organic solvent. There is further provided a conductor obtained by exposing process in which the conductive material is irradiated with active rays of 0.1 to 200 J/cm.SELECTED DRAWING: None

Description

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

  As a method for forming a metal pattern, a step of applying a conductive material such as copper or other conductive material such as conductive paste or conductive paste onto a substrate by ink jet printing, screen printing, or the like, and heating the conductive material to form metal particles A method including a step of forming a conductor and making a conductor exhibit conductivity is known. As the metal particles contained in the conductive material, those in which an organic substance as a coating material 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 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 and a conductorization method that replaces heating.
In view of the above problems, an object of the present invention is to provide a conductive composition capable of obtaining a conductor (conductor) by actinic ray irradiation treatment, a conductive material using the conductive composition, and a conductor.

Means for solving the above problems are as follows.
(1) A conductive composition comprising a salt compound of fatty acid and copper (fatty acid copper), a copper-containing particle obtained by heating a mixture of a reducing compound and an alkylamine, and a photodegradable compound.

(2) The conductive composition according to (1), wherein the thermally decomposable compound is a photopolymerization initiator.

(3) The conductive composition according to (1) or (2), wherein the photodegradable compound is 0.02 to 5.0 parts by mass with respect to 100 parts by mass of the copper-containing particles.

(4) The conductive composition according to any one of (1) to (3), wherein the fatty acid is a fatty acid having 9 or less carbon atoms.

(5) The conductivity according to any one of (1) to (4), wherein the reducing compound includes at least one selected from the group consisting of hydrazine, hydrazine derivatives, hydroxylamine, and hydroxylamine derivatives. Composition.

(6) A conductive material obtained by mixing the conductive composition according to any one of (1) to (5) in an organic solvent.

(7) A conductor obtained by subjecting the conductive material according to (6) to an exposure treatment in which an actinic ray of 0.1 to 200 J / cm ² is irradiated.

  The present invention can provide a conductive composition that can be made into a conductor at a low temperature, a conductive material that can be manufactured at a low temperature, and a conductor.

In the present specification, a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.
In the present invention, “conducting” means that the metal-containing particles are sintered to be changed into a conductive object. The “conductor (conductor)” refers to an object having conductivity, more specifically, an object having a volume resistivity of 300 μΩ · cm or less.

<Conductive composition>
The conductive composition of the present invention has copper-containing particles in which an organic substance (alkylamine or the like) is present on at least a part of the surface, and a photodegradable compound. The conductive composition of the present invention can produce a copper conductor by exposure treatment or a combination of exposure treatment and low-temperature heat treatment.

(Copper-containing particles)
The copper containing particle | grains used for this invention have the organic substance which exists in at least one part of the surface of the core particle containing copper. In a preferred embodiment of the present invention, the organic substance includes a substance derived from an alkylamine. The presence of the organic substance and the alkylamine can be obtained by heating the copper-containing particles at a temperature equal to or higher than the temperature at which the organic substance is thermally decomposed in a nitrogen atmosphere, and comparing the weights before and after the heating.

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. A hydrocarbon group which may be different or different, and may be cyclic or branched), an alkylene diamine in which two amino groups are substituted on the hydrocarbon chain, and the like. 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 number of carbon atoms of the hydrocarbon group of the alkylamine is 7 or less, when heated under the conditions specified in the method of the present invention, thermal decomposition is further promoted and good conductorization tends to be achieved. From the viewpoint of achieving better conductorization, the hydrocarbon group of the alkylamine preferably has 7 or less carbon atoms, more preferably 6 or less. More preferably, the hydrocarbon group of the alkylamine has 3 or more carbon atoms.

  Specific examples of the primary amine used in the method of the present invention include ethylamine, 2-ethoxyethylamine, propylamine, butylamine, isobutylamine, pentylamine, isopentylamine, hexylamine, cyclohexylamine, heptylamine, and octylamine. , Nonylamine, decylamine, dodecylamine, hexadecylamine, oleylamine, 3-methoxypropylamine, 3-ethoxypropylamine and the like.

  Specific examples of the secondary amine used in the method of the present invention include diethylamine, dipropylamine, dibutylamine, ethylpropylamine, ethylpentylamine, dibutylamine, dipentylamine, and dihexylamine.

  Specific examples of the alkylene diamine used in the method of the present invention include ethylene diamine, N, N-dimethylethylene diamine, N, N′-dimethyl ethylene diamine, N, N-diethyl ethylene diamine, N, N′-diethyl ethylene diamine, 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, , 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,12-diaminododecane, etc. Door can be.

  It is preferable that the organic substance which exists in at least one part of the surface of a copper containing particle | grain is 0.1-20 mass% with respect to the sum total of a core particle and organic substance. When the proportion of the organic substance is 0.1% by mass or more, sufficient oxidation resistance tends to be obtained. When the proportion of the organic substance is 20% by mass or less, conductorization at a low temperature tends to be easily achieved. The ratio of the organic substance to the total of the core particles and the organic substance is more preferably 0.3 to 10% by mass, and further preferably 0.5 to 5% by mass.

  The copper-containing particles of the present invention have at least copper-containing particles having an average particle diameter (average value of major axis lengths of 200 copper-containing particles randomly selected: average particle diameter) of 5 to 300 nm. One or more secondary structures are in close contact. Further, it has a secondary structure in which at least one copper-containing particle having an average particle diameter of 5 to 50 nm is in close contact with the copper-containing particle of 30 to 300 nm. Copper-containing particles (core particles) having an average particle diameter of 30 to 300 nm as a core mainly have a conductive function, and copper-containing particles (adhesive particles) having an average particle diameter of 5 to 50 nm adhered to the core particles are The core particles are bonded to each other by melting at a low temperature during heating. When the average particle diameter of the core particles is less than 30 nm, it is difficult to form a conductive path even if the surrounding adhesion particles are melted. When the average particle diameter is larger than 300 nm, there is a distance between the core particles. Therefore, it is difficult to form a conductive path. In addition, when the average particle diameter of the contact particles is as small as less than 5 nm, it is easily affected by oxidation, and when it is greater than 50 nm, it is difficult to melt at a low temperature, so it is difficult to adhere the core particles to each other. Become.

  The shape of the copper-containing particles of the present invention is not particularly limited. For example, a spherical shape, a long granular shape, a flat shape, a fibrous shape, and the like can be given, and can be selected according to the use of the copper-containing particles. From the viewpoint of use as a printing paste, it is preferably spherical or long granular.

  The copper-containing particles of the present invention contain at least metallic copper, and may contain other substances as necessary. Examples of substances other than copper include metals such as gold, silver, platinum, tin, and nickel, or compounds containing these metal elements, fatty acid copper described later, organic compounds derived from reducing compounds or alkylamines, copper oxide, copper chloride, etc. Can be mentioned. From the viewpoint of forming a copper pattern with excellent conductivity, the content of metallic copper in the copper-containing particles is preferably 50% by mass or more, more preferably 60% by mass or more, and 70% by mass or more. More preferably.

  Since the copper-containing particles used in the present invention contain organic substances on at least a part of the surface, oxidation of copper is suppressed even during storage in the atmosphere, and the oxide content is small. . For example, in one embodiment, the content rate of the oxide in a copper containing particle is 5 mass% or less. The oxide content in the copper-containing particles can be measured, for example, by XRD (X-ray diffraction).

(Method for producing copper-containing particles)
The method for producing the copper-containing particles used in the present invention is not particularly limited. In one preferred embodiment of the present invention, the copper-containing particles are heated in a composition containing a copper salt (fatty acid copper) of a fatty acid and copper having 9 or less carbon atoms, a reducing compound, and an alkylamine. It is manufactured by the method which has this.

  The method uses a metal salt of fatty acid and copper having 9 or less carbon atoms as a copper precursor. This makes it possible to use an alkylamine having a lower boiling point (that is, a lower molecular weight) as a reaction medium as compared with the method described in Patent Document 1 using copper oxalate or the like as a copper precursor. It is done. As a result, it is considered that the organic matter present on the surface of the obtained copper-containing particles is more easily thermally decomposed, and it becomes easier to conduct the conductor at a low temperature.

(fatty acid)
The fatty acid used in the above method is a monovalent carboxylic acid represented by RCOOH (R is a chain hydrocarbon group, which may be linear or branched). The fatty acid used in the present invention may be either a saturated fatty acid or an unsaturated fatty acid. From the viewpoint of preventing oxidation due to good coating of particles, linear saturated fatty acids are preferred. Only one type or two or more types of fatty acids may be used.

  The fatty acid 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 kind of fatty acid used in the production of the copper-containing particles of the present invention can affect properties such as dispersibility of the obtained copper-containing particles in a dispersion medium 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 a salt compound (fatty acid copper) of fatty acid and copper having 9 or less carbon atoms 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 compounds)
The reducing compound used in the above method is considered to form a complex compound such as a complex between both compounds when mixed with fatty acid copper. As a result, the reducing compound becomes an electron donor to the copper ion in the fatty acid copper, and the reduction of the copper ion is likely to occur, and the liberation of copper atoms due to spontaneous pyrolysis than the fatty acid copper in a state where no complex is formed. This is likely to occur. A reducing compound may be used individually by 1 type, or may use 2 or more types together.

  Specific examples of reducing compounds include hydrazine, hydrazine derivatives, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and other hydrazine compounds, hydroxylamine, hydroxylamine derivatives such as hydroxylamine compounds, sodium borohydride, sodium sulfite, hydrogen sulfite. Examples thereof include sodium compounds such as sodium, sodium thiosulfate, and sodium hypophosphite.

  A reducing compound having an amino group is preferable from the viewpoints of easily forming a coordination bond to a copper atom in fatty acid copper, and easily forming a complex while maintaining the structure of fatty acid copper. Examples of the reducing compound having an amino group include hydrazine and derivatives thereof, hydroxylamine and derivatives thereof, and the like.

  From the viewpoint of lowering the heating temperature (for example, 150 ° C. or lower) in the step of heating the composition containing fatty acid copper, the reducing compound and the alkylamine in the method (hereinafter also referred to as the heating step), the evaporation of the alkylamine or It is preferable to select a reducing compound capable of forming a complex that causes reduction and liberation of a copper atom in a temperature range that does not cause decomposition. Examples of such reducing compounds include hydrazine and its derivatives, hydroxylamine and its derivatives, and the like. These reducing compounds can form a complex by forming a coordinate bond with a copper atom by a nitrogen atom forming a skeleton. In addition, since these reducing compounds generally have a stronger reducing power than alkylamines, the resulting complexes tend to spontaneously decompose under relatively mild conditions, and tend to reduce and release copper atoms.

  By selecting a suitable one of these derivatives instead of hydrazine or hydroxylamine, the reactivity with the fatty acid copper can be adjusted, and a complex that generates spontaneous decomposition under a desired condition can be generated. 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 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.

(Alkylamine)
The alkylamine used in the above method is considered to function as a reaction medium for the decomposition reaction of the complex formed from the fatty acid copper and the reducing compound. Furthermore, it is considered that protons generated by the reducing action of the reducing compound are captured, and the reaction solution is inclined to be acidic and copper atoms are prevented from being oxidized.

  The alkylamine preferably contains at least one alkylamine whose hydrocarbon group has 7 or less carbon atoms. Thereby, the copper containing particle | grains which can more easily achieve conductorization at low temperature can be manufactured. The alkylamine may be used alone or in combination of two or more, and the kind and preferred form thereof are the same as those described in relation to the organic substance present on the surface of the copper-containing particle of the present invention. The alkylamine may include an alkylamine having a hydrocarbon group having 7 or less carbon atoms and an alkylamine having a hydrocarbon group having 8 or more carbon atoms. When an alkylamine having a hydrocarbon group having 7 or less carbon atoms and an alkylamine having 8 or more carbon atoms in a hydrocarbon group are used in combination, the alkylamine having a hydrocarbon group having 7 or less carbon atoms in the entire alkylamine Is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more.

  The ratio of copper and alkylamine contained in fatty acid copper is not particularly limited as long as desired copper-containing particles are obtained. For example, the ratio (copper: alkylamine) can be in a range of 1: 1 to 1: 8 on a molar basis, preferably in a range of 1: 1 to 1: 6, and 1: 1 to 1: A range of 4 is more preferable.

(Heating process)
In the said method, the method in particular for implementing the process of heating the composition containing 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.

  In the said method, a heating process can be performed at comparatively low temperature by using the fatty acid copper whose carbon number is 9 or less as a copper precursor. For example, it can be performed at 150 ° C. or lower, preferably 130 ° C. or lower, more preferably 100 ° C. or lower.

  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 a solvent having solubility 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. A solvent may be used individually by 1 type, or may use 2 or more types together.

  As alcohol which shows the solubility with respect to water at 25 degreeC, C1-C8 can be mentioned and the alcohol which has one hydroxyl group in a molecule | numerator can be mentioned. Examples of such alcohols include linear alkyl alcohols, phenols, and those obtained by replacing hydrogen atoms of hydrocarbons having an ether bond in the molecule with hydroxyl groups. From the viewpoint of expressing a stronger polarity, an alcohol having two or more hydroxyl groups in the molecule is also preferably used. Moreover, you may use alcohol containing a sulfur atom, a phosphorus atom, a silicon atom, etc. according to the use of the copper containing particle | grains manufactured.

  Specific examples of alcohol used as a solvent include methanol, ethanol, 1-propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, allyl alcohol, benzyl alcohol, pinacol, propylene glycol, menthol, catechol, hydroquinone, Examples include salicyl alcohol, glycerin, pentaerythritol, sucrose, glucose, xylitol, methoxyethanol, triethylene glycol monomethyl ether, ethylene glycol, triethylene glycol, tetraethylene glycol, and pentaethylene glycol.

  Among the alcohols, methanol, ethanol, 1-propanol and 2-propanol having a very high solubility in water are preferable, 1-propanol and 2-propanol are more preferable, and 1-propanol is still more preferable.

(Photodegradable compounds)
The photodegradable compound used in the present invention includes a photopolymerization initiator, and preferably has an absorption band at 300 to 400 nm in order to improve sensitivity during pattern formation.

  Specific examples of the photopolymerization initiator include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy- 4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy- Aromatic ketones such as cyclohexyl-phenyl-ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropanone-1,2,4-diethylthioxanthone, 2-ethylanthraquinone and phenanthrenequinone, benzoin Methyl ether, benzoin ethyl ether and benzoin phenyl ether Benzoin ethers such as tellurium, benzoins such as methylbenzoin and ethylbenzoin, benzyl derivatives such as benzyldimethyl ketal, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4 , 5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer 2-mer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer and 2- (2,4-dimethoxy) 2,4,5-triarylimidazole dimer such as phenyl) -4,5-diphenylimidazole dimer, 9 Acridine derivatives such as phenylacridine and 1,7-bis (9,9'-acridinyl) heptane, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and bis (2,4 , 6, -trimethylbenzoyl) -phenylphosphine oxide and the like. These can be used alone or in combination of two or more. By utilizing the decomposition heat generated by these compounds at the time of exposure, the conductorization of the copper particles can be promoted even when the conductorization temperature is 150 ° C. or less, and damage to the substrate can be reduced.

  In the method for making a conductive composition of the present invention into a conductor, the state of the conductive composition to be exposed or heated is not particularly limited. For example, the conductive composition may be exposed or heated as it is, and may be mixed with a desired dispersion medium to form a conductive material such as ink or paste. When the conductive composition of the present invention is made into a conductor, the effect is more remarkable when the state of the composition is a conductive material. The shape of the copper-containing particles is not particularly limited. For example, a spherical shape, a long granular shape, a flat shape, a fibrous shape, and the like can be given, and can be selected according to the use of the copper-containing particles. From the viewpoint of use as a printing paste, it is preferably spherical or long granular.

  In the conductive composition of the present invention, as described above, the average value of the particle diameter (the average value of the major axis length of 200 randomly selected copper-containing particles) is 5 to 300 nm. Have a secondary structure in which at least one of them is in close contact. Further, it has a secondary structure in which at least one copper-containing particle having an average particle diameter of 5 to 50 nm is in close contact with the copper-containing particle of 30 to 300 nm. Copper-containing particles (core particles) having an average particle diameter of 30 to 300 nm as a core mainly have a conductive function, and copper-containing particles (adhesive particles) having an average particle diameter of 5 to 50 nm adhered to the core particles are The core particles are bonded to each other by melting at a low temperature during heating. When the average particle diameter of the core particles is less than 30 nm, it is difficult to form a conductive path even if the surrounding adhesion particles are melted. When the average particle diameter is larger than 300 nm, there is a distance between the core particles. Therefore, it is difficult to form a conductive path. In addition, when the average particle diameter of the contact particles is as small as less than 5 nm, it is easily affected by oxidation, and when it is greater than 50 nm, it is difficult to melt at a low temperature, so it is difficult to adhere the core particles to each other. Become.

  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 is the two values (100th and 101st) located at the center when the major axis length values of 200 copper-containing particles are arranged in ascending order. Means the arithmetic mean. 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.

  When making the composition of this invention into a conductor, you may include another process as needed. Other steps include a step of reducing copper oxide generated by heating in a reducing atmosphere after the heating step, a step of removing residual components by light baking after the heating step, and a step of applying a load after the heating step. it can.

(Conductive material)
The conductive composition of the present invention may contain a dispersion medium and other components as necessary. By mixing the conductive composition of the present invention with a dispersion medium to form a paste and an ink, various printing methods can be supported.

  The dispersion medium used when the conductive composition of the present invention is made into a paste or ink is not particularly limited, and can be selected from organic solvents generally used for the production of conductive inks, conductive pastes, and the like according to applications. . For example, terpineol, isobornylcyclohexanol, dihydroterpineol, dihydroterpineol acetate and the like are preferable from the viewpoint of viscosity control. The conductive material (conductive paste or conductive ink) of the present invention is obtained by mixing the conductive composition with an organic solvent.

  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 paste 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 inkjet printing method, it is preferably a conductive ink having a viscosity of 0.1 to 30 mPa · s at the temperature to be used, depending on the standard of the inkjet head to be used. -It is more preferable that it is s.

<Conductor (conductor)>
The shape of the conductor (conductor) manufactured by the conductive material 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 components. In particular, since a conductor manufactured using the conductive material of the present invention does not require a heating process or can be manufactured at a temperature lower than that of a conventional process, a metal foil, a wiring pattern, or the like is formed on a substrate having low heat resistance such as a resin. It is suitably used for applications.

  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. Alternatively, heating may be performed in an atmosphere in which a reducing substance such as hydrogen or formic acid is saturated with, for example, nitrogen described above. The pressure during heating is not particularly limited, but a reduction in temperature can be expected by reducing the pressure.

In the method for making a conductive material of the present invention into a conductor, the output during the exposure process is preferably 0.1 to 200 J / cm ² . If the exposure amount is less than 0.1 J / cm ² is not sufficient energy for assisting the sintering, it is possible that damage to the substrate is greater exceed 200 J / cm ^2. The actinic rays at the time of the exposure treatment are, for example, electron beams, ultraviolet rays, α rays, γ rays, and X-rays, and preferably ultraviolet rays.

  In the method for converting a conductive material of the present invention into a conductor, the heating step may be performed at a constant rate of temperature increase or 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.

  When a conductive material is provided on a substrate and heated to form the conductor of the present invention, the material of the substrate is not particularly limited and may or may not have conductivity. 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.

  The volume resistivity of the conductor produced by the method of the present invention is 300 μΩ · cm or less, preferably 200 μΩ · cm or less, more preferably 100 μΩ · cm or less, and 50 μΩ · cm or less. Is more preferably 10 μΩ · cm or less.

  The copper film formed of the conductive material of the present invention can be used for, for example, electrical wiring such as a laminated plate, a solar cell panel, a display, and a transistor, a heat dissipation film, a surface coating film, and a semiconductor package.

  Hereinafter, although the conductive composition, 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 synthesize a salt compound (fatty acid copper) of fatty acid and copper, 91.5 g (0.94 mol) of copper hydroxide (Kanto Chemical Co., Ltd., special grade) and 1-propanol (Kanto) 150 mL of Chemical Co., Ltd. (special grade) was added and stirred, and 370.9 g (2.34 mol) of nonanoic acid (Kanto Chemical Co., Inc., purity 90 mass% or more) was added as a fatty acid. 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 copper nonanoate, which was the produced fatty acid copper, was suction filtered and washed with hexane until the cleaning 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 15.01 g (0.040 mol) of nonanoate copper (II) obtained as fatty acid copper and 7.21 g of copper (II) acetate anhydride (Kanto Chemical Co., Ltd., special grade) (0.040 mol) was put into a separable flask, 10 mL of 1-propanol and 32.1 g (0.32 mol) of hexylamine (Tokyo Chemical Industry Co., Ltd., purity 99% by mass) as an alkylamine were added, and in an oil bath It was heated and stirred at 80 ° C. to dissolve. After moving to an ice bath and cooling until the internal temperature reaches 5 ° C., 7.72 mL (0.16 mol) of hydrazine monohydrate (Kanto Chemical Co., Ltd., special grade) as a reducing compound is dissolved in 12 mL of 1-propanol. The solution was added to the fatty acid copper solution and stirred in an ice bath. The molar ratio of copper: hexylamine is 1: 4. Subsequently, it heated and stirred at 90 degreeC in the oil bath. At that time, the reduction reaction accompanied with foaming progressed, and the reaction was completed within 10 minutes. The inner wall of the separable flask had a copper luster and the solution turned dark red. Centrifugation was performed at 9000 (rev / min) for 1 minute to obtain a solid. The process of further washing the solid with 15 mL of hexane was repeated three times to remove the acid residue, thereby obtaining a copper cake containing powder of copper particles (copper-containing particles) having copper luster.

The copper cake (60 parts by mass), terpineol (20 parts by mass) as an organic solvent, and isobornylcyclohexanol (trade name: Tersolve MTPH, Nippon Terpene Chemical Co., Ltd.) (20 parts by mass), N as a photodegradable compound , N′-tetramethyl-4,4′-diaminobenzophenone (0.02 parts by mass) was mixed to prepare a conductive material. The obtained conductive material was applied on a polyethylene naphthalate (PEN) film and exposed at 10 J / cm ² to form a thin metal copper film.

<Example 2>
The same operation as in Example 1 was performed except that N, N′-tetramethyl-4,4′-diaminobenzophenone (0.2 parts by mass) was mixed.

<Example 3>
The same operation as in Example 1 was carried out except that N, N'-tetramethyl-4,4'-diaminobenzophenone (1.0 part by mass) was mixed.

<Example 4>
The same operation as in Example 1 was conducted except that N, N′-tetramethyl-4,4′-diaminobenzophenone (5.0 parts by mass) was mixed.

<Comparative Example 1>
It replaced with the exposure process and implemented similarly to Example 1 except having heat-processed at 140 degreeC for 1 hour.

<Comparative example 2>
The same procedure as in Example 1 was performed except that N, N′-tetramethyl-4,4′-diaminobenzophenone was not mixed.

<Reference Example 1>
The same operation as in Example 1 was carried out except that N, N′-tetramethyl-4,4′-diaminobenzophenone (0.002 parts by mass) was mixed.

(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.) Table 1 shows the results calculated from the film thickness obtained by Ryoka System.

以上より、本発明の導電性組成物は良好な導電性を示すことがわかった。

As mentioned above, it turned out that the electroconductive composition of this invention shows favorable electroconductivity.

Claims (7)

  A conductive composition comprising a salt compound of fatty acid and copper (fatty acid copper), a copper-containing particle obtained by heating a mixture of a reducing compound and an alkylamine, and a photodegradable compound.   The conductive composition according to claim 1, wherein the photodegradable compound is a photopolymerization initiator.   The conductive composition according to claim 1, wherein the photodegradable compound is 0.02 to 5.0 parts by mass with respect to 100 parts by mass of the copper-containing particles.   The conductive composition according to any one of claims 1 to 3, wherein the fatty acid is a fatty acid having 9 or less carbon atoms.   5. The conductive composition according to claim 1, wherein the reducing compound includes at least one selected from the group consisting of hydrazine, a hydrazine derivative, hydroxylamine, and a hydroxylamine derivative.   The electroconductive material obtained by mixing the electroconductive composition as described in any one of Claims 1-5 with the organic solvent. A conductor obtained by subjecting the conductive material according to claim 6 to an exposure treatment in which an actinic ray of 0.1 to 200 J / cm ² is irradiated.