JP2024003418A - conductive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive composition that results in a cured film having superior resistance to high temperature and high humidity.

SOLUTION: A conductive composition contains (a) C8-18 aliphatic monocarboxylic acid, (b) an isocyanuric acid derivative represented by the formula (1), and (c) conductive particles. Based on the total 100 mass% of (a)-(c), the content of (a) is 0.05-10 mass%, the content of (b) is 0.05-10 mass%, and the content of (c) is 80-99.9 mass%.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to electrically conductive compositions.

In recent years, from the perspective of Sustainable Development Goals (SDGs), the conventional wet etching method that uses large amounts of chemicals has been replaced with printing methods using screen printers, etc. in the circuit formation method of electronic components. ing. Under these circumstances, many studies are being conducted to form circuits using a screen printing machine, which is a general-purpose printing method, and progress is being made to develop the composition of a conductive paste suitable for screen printing as a material for this purpose.

An advantage of circuit formation using screen printing is that it is possible to simultaneously form linear printed patterns with a line width of about 0.1 mm to 1.0 mm and planar printed patterns with a side of several mm to several tens of mm. Therefore, there is a high degree of freedom in circuit design. For example, Patent Document 1 describes a specific conductive paste (conductive disclosed.

JP2021-170510

However, although the conductive paste disclosed in Patent Document 1 has excellent printability and conductivity for a linear pattern with a line width of about 1 mm, when a planar pattern is printed, the solvent components contained in the conductive paste becomes difficult to volatilize from inside the solid film after heating, and the insulating component in the cured film increases, which may deteriorate the conductivity. In addition, if the solvent is difficult to volatilize from inside the planar pattern, the proportion of the solvent that volatilizes after the binder resin contained in the conductive paste is cured increases, making it easy for fine voids to form in the cured film. Become. Therefore, when the cured film is subjected to a high temperature and high humidity test, there is a risk that the conductivity may deteriorate.

The problem to be solved by the present invention is that when a planar pattern is printed by screen printing, it is possible to obtain a cured film having excellent conductivity equivalent to that of a linear pattern, and that the obtained cured film is An object of the present invention is to provide a conductive composition having good high temperature and high humidity resistance.

As a result of repeated studies to solve the above problems, the present inventors solved the above problems by blending an isocyanuric acid derivative containing a specific structure in addition to conductive particles and an aliphatic monocarboxylic acid. The present inventors have discovered that it is possible to provide a conductive composition that can provide a conductive composition, and have completed the present invention.

That is, the present invention contains (a) an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (b) an isocyanuric acid derivative represented by formula (1), and (c) conductive particles, and the component ( With respect to the total of 100% by mass of a) to (c), the content of component (a) is 0.05 to 10% by mass, the content of component (b) is 0.05 to 10% by mass, and the content of component (c) is 0.05 to 10% by mass. ) The conductive composition has a content of 80 to 99.9% by mass.

[In formula (1), k, m, and n are integers of 1 to 3, and R ¹ to R ⁹ are each independently a methyl group or an ethyl group. ]

When the conductive composition of the present invention is printed with a planar pattern by screen printing, it is possible to obtain a cured film having excellent conductivity equivalent to that of a linear pattern. Furthermore, the obtained cured film has good high temperature and high humidity resistance, and is suitable as a circuit forming material for electronic materials.

Embodiments of the present invention will be described below.
In addition, in this specification, the numerical range defined using the symbol "~" shall include the numerical values at both ends (upper limit and lower limit) of "~". For example, "2-5" represents 2 or more and 5 or less. Furthermore, if a concentration or amount is specified, any higher concentration or amount can be associated with any lower concentration or amount. For example, when there is a description of "2 to 10% by mass" and "preferably 4 to 8% by mass", "2 to 4% by mass", "2 to 8% by mass", "4 to 10% by mass" and "8% by mass" This also includes descriptions of "up to 10% by mass."

The conductive composition according to the embodiment of the present invention includes (a) an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (b) an isocyanuric acid derivative represented by formula (1), and (c) conductivity. Contains particles. The content of component (a) is 0.05 to 10% by mass, and the content of component (b) is 0.05 to 10% by mass, based on the total of 100% by mass of components (a) to (c). , the content of component (c) is 80 to 99.9% by mass.

[In formula (1), k, m, and n are integers of 1 to 3, and R ¹ to R ⁹ are each independently a methyl group or an ethyl group. ]

Each component will be explained below.

[Component (a): Aliphatic monocarboxylic acid]
Component (a) used in the present invention is an aliphatic monocarboxylic acid having 8 to 18 carbon atoms. Examples of aliphatic monocarboxylic acids include linear saturated aliphatic monocarboxylic acids, linear unsaturated aliphatic monocarboxylic acids, branched saturated aliphatic monocarboxylic acids, and branched unsaturated aliphatic monocarboxylic acids. One type selected from the above compounds can be used alone, or two or more types can be used in combination.

Examples of linear saturated aliphatic monocarboxylic acids having 8 to 18 carbon atoms include caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, and stearin. Examples include acids. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include myristoleic acid, palmitoleic acid, petroselic acid, and oleic acid. Examples of the branched saturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include 2-ethylhexanoic acid.

From the viewpoint of electrical conductivity, component (a) is preferably an aliphatic monocarboxylic acid having 8 to 16 carbon atoms, more preferably 8 to 12 carbon atoms.

The content of component (a) is 0.05 to 10% by weight, preferably 0.05 to 5% by weight, based on the total of 100% by weight of components (a) to (c). If the content of component (a) is less than 0.05% by mass or more than 10% by mass, the volume resistivity of the cured film obtained using the conductive composition may increase.

[Component (b) isocyanuric acid derivative represented by formula (1)]
Component (b) used in the present invention is an isocyanuric acid derivative represented by the above-mentioned formula (1).

In formula (1), R ¹ to R ⁹ may each independently be either a methyl group or an ethyl group, but R ¹ to R ³ , R ⁴ to R ⁶ , and R ⁷ to R ⁹ are the same. Preferably, those in which R ¹ to R ⁹ are all the same are more preferable. Further, k, m, and n may each independently be integers of 1 to 3, but preferably are the same number.

Component (b) includes, for example, tris[3-(trimethoxysilyl)methyl] isocyanurate, tris[3-(trimethoxysilyl)ethyl] isocyanurate, tris[3-(trimethoxysilyl)propyl] isocyanurate. , tris[3-(triethoxysilyl)methyl] isocyanurate, tris[3-(triethoxysilyl)ethyl] isocyanurate, tris[3-(triethoxysilyl)propyl] isocyanurate, tris[3-(triethoxysilyl)propyl] isocyanurate dimethoxyethoxysilyl)methyl], tris[3-(diethoxymethoxysilyl)methyl] isocyanurate, tris[3-(dimethoxyethoxysilyl)ethyl] isocyanurate, tris[3-(diethoxymethoxysilyl)ethyl] isocyanurate , tris[3-(dimethoxyethoxysilyl)propyl] isocyanurate, tris[3-(diethoxymethoxysilyl)propyl] isocyanurate, and the like.

One type selected from the above compounds represented by formula (1) can be used alone, or two or more types can be used in combination. In particular, it is recommended to select and use one or more of tris[3-(trimethoxysilyl)propyl] isocyanurate and tris[3-(triethoxysilyl)propyl] isocyanurate to improve conductivity and high temperature and high humidity resistance. It is preferable from the viewpoint of electrical conductivity, and tris[3-(trimethoxysilyl)propyl] isocyanurate is more preferable from the viewpoint of electrical conductivity.

The content of component (b) is 0.05 to 10% by mass, preferably 0.05 to 5% by mass, based on the total of 100% by mass of components (a) to (c). When the content of component (b) is less than 0.05% by mass or more than 10% by mass, the volume resistivity of the cured film obtained using the conductive composition may increase.

Component (b) can be produced according to known methods such as a condensation reaction of isocyanate groups, but is also available as a commercially available product. Examples of commercially available products include, but are not limited to, KBM-9659 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[Component (c): conductive particles]
Component (c) is a conductive particle, and for example, inorganic conductive particles such as copper particles can be used. The copper particles may be made of only copper, but may also contain metals other than copper, such as silver and platinum, metal oxides, and metal sulfides. When the copper particles further contain a metal other than copper, a metal oxide, or a metal sulfide, the mass ratio of copper in the copper particles is preferably 50% by mass or more. Further, the copper particles may have a shape in which a surface layer or protrusions are formed.

Although commercially available conductive particles may be used as they are, it is preferable to use surface-coated conductive particles whose surfaces are coated for the purpose of improving oxidation resistance. Among them, it is preferable to use surface-coated conductive particles whose surfaces are coated with an amine compound, and it is more preferable to use surface-coated conductive particles whose surfaces are coated with an amine compound represented by the following formula (2).

(In formula (2), m is an integer of 0 to 3, n is an integer of 0 to 2, and when n=0, m is any one of 0 to 3, and when n=1 or n=2 , m is any one from 1 to 3.)

Surface-coated conductive particles whose surfaces are coated with an amine compound such as the amine compound represented by the above formula (2) are further coated with an aliphatic monocarboxylic acid from the viewpoint of obtaining better oxidation resistance. It is preferable to use conductive particles.

As a result, the surface of the conductive particles is coated with a first coating layer made of an amine compound and a second coating layer made of an aliphatic monocarboxylic acid. Preferably, the first coating layer is formed on the surface of the conductive particle, and the second coating layer is formed on the first coating layer.

The aliphatic monocarboxylic acid forming the second coating layer is preferably an aliphatic monocarboxylic acid having 8 to 24 carbon atoms. Examples of the aliphatic monocarboxylic acids include linear saturated aliphatic monocarboxylic acids, linear unsaturated aliphatic monocarboxylic acids, branched saturated aliphatic monocarboxylic acids, and branched unsaturated aliphatic monocarboxylic acids.
Examples of linear saturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, and stearin. acid, nonadecylic acid, arachidic acid, etc. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 24 carbon atoms include myristoleic acid, palmitoleic acid, petroselic acid, and oleic acid. Examples of the branched saturated aliphatic monocarboxylic acid having 8 to 24 carbon atoms include 2-ethylhexanoic acid. As the aliphatic monocarboxylic acid, one type selected from the above compounds can be used alone, or two or more types can be used in combination.

The method for producing surface-coated conductive particles is not particularly limited. As a method for obtaining surface-coated conductive particles whose surfaces are coated with an amine compound, for example, the conductive particles are washed with, for example, an aqueous ammonium chloride solution, and then the washed conductive particles are added to a solution of the amine compound. , a method of heating as necessary, and a method of adding conductive particles to a solution containing, for example, ammonium chloride and an amine compound and heating as necessary.

As a method for producing surface-coated conductive particles coated with a first coating layer formed of an amine compound and a second coating layer formed of an aliphatic monocarboxylic acid, for example, A method of adding surface-coated conductive particles to a solution of an aliphatic monocarboxylic acid may be mentioned. In addition, after adding to the solution of aliphatic monocarboxylic acid, heating may be performed as necessary.

The average particle diameter (D50) of the conductive particles is not particularly limited, but the conductive composition containing the conductive particles as component (c) can be printed well in various printing methods such as dispenser printing and screen printing. In order to achieve this, it is preferable to control the average particle diameter (D50) of the conductive particles. Specifically, the average particle diameter (D50) of the conductive particles is preferably 5 nm to 20 μm, more preferably 10 nm to 10 μm.

The average particle diameter (D50) of the conductive particles can be measured using a laser diffraction/scattering particle size distribution analyzer (Microtrac MT3000II, manufactured by Microtrac Bell Co., Ltd.).

Further, the BET specific surface area of the conductive particles is preferably 0.05 to 400 m ² /g, more preferably 0.1 to 200 m ² /g. The BET specific surface area of the conductive particles can be measured by the BET one-point method using a specific surface area measuring device (Monosorb, manufactured by Yuasa Ionics Co., Ltd.).

There are no particular restrictions on the shape or aspect ratio (ratio of the major axis to the minor axis of the particles) of the conductive particles, and they may be spherical, polyhedral, flat, plate-shaped, flaky, flaky, rod-shaped, dendritic, fibrous, etc. Various shapes can be used. As the conductive particles, one type selected from those having different constituent components, average particle size, shape, aspect ratio, etc. can be used alone, or two or more types can be used in combination.

The content of component (c) is 80 to 99.9% by mass based on the total of 100% by mass of components (a) to (c). The lower limit of the content of component (c) is preferably 85% by mass, more preferably 90% by mass.

[Other ingredients]
In addition to the above-mentioned components (a) to (c), the conductive composition may contain a binder resin, a solvent, an antioxidant, a lubricant, a leveling agent, a dispersant, a curing agent, and a curing agent, to the extent that the effects of the present invention are not impaired. It may contain various additives such as accelerators, viscosity modifiers, foaming agents, and antifoaming agents. Further, the conductive composition may contain impurities that may inevitably be mixed in from raw material components, equipment during the manufacturing process, and the like. In addition, when any of these components is included, the total content can be more than 0 parts by mass and 70 parts by mass or less, and 50 parts by mass or less, based on 100 parts by mass of the total content of (a) to (c). It is preferably less than parts by mass.

(binder resin)
The conductive composition may contain a binder resin for the purpose of controlling film formability and viscosity. As the binder resin, known binder resins used in conductive compositions etc. can be used, and examples thereof include thermosetting resins, photocurable resins, and thermoplastic resins that are cured by heating or light irradiation. .

Examples of thermosetting resins include epoxy resins, melamine resins, phenolic resins, silicone resins, polyurethane resins, unsaturated polyester resins, vinyl ester resins, polyvinylphenol resins, xylene resins, acrylic resins, oxetane resins, diallyl phthalate resins, etc. can be mentioned. Examples of the photocurable resin include acrylic resin, imide resin, urethane resin, and oxetane resin. Examples of the thermoplastic resin include, but are not limited to, polyolefin resins such as polyamide, polyethylene terephthalate, and polyethylene; and acrylonitrile-butadiene-styrene copolymer resins. The binder resin can be used alone or in combination of two or more. The mixing ratio in the case of mixing two or more types is not particularly limited. As the type of binder resin, it is preferable to use one or more types selected from thermosetting resins such as epoxy resins, phenol resins, and polyvinylphenol resins. The mixing ratio when two or more of these binder resins are mixed is also not particularly limited.

When the conductive composition contains a binder resin, the content of the binder resin is preferably 0.5 to 50 parts by mass based on the solid content based on 100 parts by mass of the total content of components (a) to (c). Parts by weight, more preferably 1 to 30 parts by weight.

(solvent)
The conductive composition may contain a solvent for the purpose of improving coatability and adjusting viscosity.

Examples of the solvent include ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, and triethylene glycol monomethyl. Ether alcohols such as ether, tetraethylene glycol dimethyl ether, tetraethylene glycol, dipropylene glycol; Non-ether alcohols such as propylene glycol, 1,4-butanediol; cyclohexanol acetate, methyl methoxypropionate, ethyl ethoxy Esters such as propionate and 1,6-hexanediol acetate; Ketones such as isophorone and cyclohexanone; Terpenes such as terpineol, dihydroterpineol, dihydroterpinyl acetate, and isobornylcyclohexanol; octane, decane, and dodecane , tetradecane, hexadecane, propylene carbonate, and other hydrocarbons, but are not limited thereto. One type of solvent can be used alone, or two or more types can be used in combination. The mixing ratio in the case of mixing two or more types is not particularly limited.

As the type of solvent, it is preferable to use one or more selected from the above ether alcohols, the above esters, and the above terpenes. The mixing ratio when two or more of these solvents are mixed is also not particularly limited.

When the conductive composition contains a solvent, the content of the solvent is preferably 1 to 30 parts by mass, more preferably 2 parts by mass, based on 100 parts by mass of the total content of components (a) to (c). ~20 parts by mass.

(Antioxidant)
The conductive composition may contain an antioxidant for the purpose of maintaining the performance of each component during storage. There is no particular restriction on the type of antioxidant, and various antioxidants can be used depending on the purpose and the like. For example, nitrogen-containing heterocyclic compounds such as 2,2-bipyridyl and 1,10-phenanthroline, N,N'-bis(salicylidene)ethylenediamine, N,N'-bis(salicylidene)-1,2-propanediamine, Schiff bases such as N,N'-bis(salicylidene)-1,3-propanediamine, N,N'-bis(salicylidene)-1,2-phenylenediamine, 1,2-phenylenediamine, 1,3- Phenylene diamine, 1,4-phenylene diamine, 2,5-dimethyl-1,4-phenylene diamine, 2,3,5,6-tetramethyl 1,4-phenylene diamine, N,N-dimethyl-1,4- Aromatic diamines such as phenylenediamine, N,N,N'N'-tetramethyl-1,4-phenylenediamine, N,N'-diphenyl-1,4-phenylenediamine, p-methoxyphenol, hydroquinone, tert - Phenols such as butylhydroquinone, dibutylhydroxytoluene, catechol, 4-tert-butylcatechol, pyrogallol, eugenol, propyl gallate, etc., L-ascorbic acid, 6-O-palmitoyl-L-ascorbic acid, 6-O- Examples include, but are not limited to, ascorbic acids such as stearoyl-L-ascorbic acid and ascorbyl tetra-2-hexyldecanoate. The antioxidants can be used alone or in combination of two or more. The mixing ratio in the case of mixing two or more types is not particularly limited.

Examples of the antioxidant include 2,2-bipyridyl of the nitrogen-containing heterocyclic compounds mentioned above, N,N'-bis(salicylidene)ethylenediamine of the above Schiff bases, N,N'-bis(salicylidene)-1, 2-propanediamine, the aromatic diamines 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, the phenols p-methoxyphenol, hydroquinone, tert-butylhydroquinone, and It is preferable to use one or more selected from the above ascorbic acids, 6-O-palmitoyl-L-ascorbic acid and 6-O-stearoyl-L-ascorbic acid. When two or more of these antioxidants are mixed, the mixing ratio is not particularly limited.

When the conductive composition contains an antioxidant, the content of the antioxidant is preferably 0.01 to 10 parts by mass based on 100 parts by mass of the total content of components (a) to (c). The amount is more preferably 0.1 to 5 parts by mass.

The above-mentioned conductive composition can be obtained by blending predetermined amounts of each of the above-mentioned components and kneading according to a conventional method. Further, a cured film can be obtained by printing a desired pattern on the surface of a base material using a conductive composition by screen printing or the like according to a conventional method, and then subjecting the material to a heat treatment or the like. In addition, by containing the above-mentioned predetermined component composition, the conductive composition can become a cured film with excellent conductivity equivalent to the planar pattern and the linear pattern formed by screen printing. This allows simultaneous formation of linear patterns and planar patterns. Further, the obtained cured film has good high temperature and high humidity resistance. Therefore, the above-mentioned conductive composition is suitable for circuit formation by screen printing, that is, for screen printing. The conductivity and high temperature and high humidity resistance of the cured film of the conductive composition can be evaluated, for example, by the method described in the Examples section below.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples and Comparative Examples.

Each component used in Examples and Comparative Examples is shown below. Note that the physical properties of each component are values measured by the method described in this specification.

[Component (a): aliphatic monocarboxylic acid having 8 to 18 carbon atoms]
・2-ethylhexanoic acid (branched saturated aliphatic monocarboxylic acid with 8 carbon atoms)
・Lauric acid (linear saturated aliphatic monocarboxylic acid with 12 carbon atoms)
・Stearic acid (linear saturated aliphatic monocarboxylic acid with 18 carbon atoms)

[Component (b): isocyanuric acid derivative represented by formula (1)]
(b1): Tris[3-(trimethoxysilyl)methyl] isocyanurate (Synthesis Example 1 below)
(b2): Tris[3-(trimethoxysilyl)ethyl] isocyanurate (Synthesis Example 2 below)
(b3): Tris[3-(trimethoxysilyl)propyl] isocyanurate (KBM-9659, manufactured by Shin-Etsu Chemical Co., Ltd.)
(b4): Tris[3-(triethoxysilyl)propyl] isocyanurate (Synthesis Example 3 below)

[Component (b'): isocyanuric acid derivative different from component (b)]
(b5): Tris(2,3-epoxypropyl) isocyanurate (TEPIC (registered trademark)-G, manufactured by Nissan Chemical Industries, Ltd.)

Table 1 shows the relationship between the isocyanuric acid derivatives b1 to b5 and the structure of formula (1).

[Component (c): conductive particles]
- Copper particles (1): Spherical copper particles [surface-coated copper particles (1), the manufacturing method of which is shown in Synthesis Example 4 below. ]
- Copper particles (2): plate-shaped copper particles [surface-coated copper particles (2), the manufacturing method of which is shown in Synthesis Example 5 below. ]

[Other ingredients]
(binder resin)
・Resol type phenolic resin [PL-5208, manufactured by Gunei Chemical Industry Co., Ltd., solid content 60.0% by mass, solvent: diethylene glycol monoethyl ether]
(Antioxidant)
・N,N'-bis(salicylidene)ethylenediamine (solvent)
・Terpineol

[Synthesis example 1]
(b1: Production of tris[3-(trimethoxysilyl)methyl] isocyanurate)
In a reaction vessel, 200 g of dimethyl sulfoxide, 200 g of 3-(trimethoxysilyl)methyl isocyanate, and 1 g of sodium methoxide were mixed, and after stirring at 100°C for 6 hours, the reaction solution was cooled to 20°C. Stirring was performed using a mechanical stirrer at a rotation speed of 100 rpm. , 5A filter paper was used to filter the resulting reaction solution under reduced pressure to remove insoluble matter in the reaction solution. The reaction solution after filtration was concentrated under reduced pressure at 150° C. to obtain the target product, tris[3-(trimethoxysilyl)methyl] isocyanurate.

[Synthesis example 2]
(b2: Production of tris[3-(trimethoxysilyl)ethyl] isocyanurate)
Tris[3-(trimethoxysilyl)ethyl] isocyanurate was obtained in the same manner as in Synthesis Example 1, except that 3-(trimethoxysilyl)methyl isocyanate was changed to 3-(trimethoxysilyl)ethyl isocyanate. Ta.

[Synthesis example 3]
(b4: Production of tris[3-(triethoxysilyl)propyl] isocyanurate)
Tris[3-(triethoxysilyl)propyl] isocyanurate was obtained in the same manner as in Synthesis Example 1 except that 3-(trimethoxysilyl)methyl isocyanate was changed to 3-(triethoxysilyl)propyl isocyanate. Ta.

[Synthesis example 4]
(Copper particles (1): Production of surface-coated copper particles (1))
An aqueous ammonium chloride solution was prepared by dissolving 5 g of ammonium chloride in 100 g of water. 50 g of copper particles a [“1200Y” manufactured by Mitsui Mining & Mining Co., Ltd.; particle size (D50) 2 μm, BET specific surface area 0.40 m ² /g, shape: spherical] were added to an ammonium chloride aqueous solution, and under nitrogen bubbling, The mixture was stirred at 30°C for 60 minutes. Stirring was performed using a mechanical stirrer at a rotation speed of 150 rpm. Hereinafter, stirring was performed using the same stirring device at the same rotation speed. After the stirring was completed, the copper particles were filtered out by vacuum filtration using a Kiriyama funnel made of 5C filter paper, and then the copper particles were washed twice with 150 g of water on the Kiriyama funnel.
The washed copper particles were added to 250 g of a 40% by mass diethylenetriamine aqueous solution, and heated and stirred at 60° C. for 1 hour under nitrogen bubbling.
After the stirring was stopped and the mixture was allowed to stand for 5 minutes, about 200 g of supernatant liquid was drawn out and removed. Subsequently, 200 g of isopropanol was added to the precipitate as a cleaning solvent, and the mixture was stirred at 30° C. for 3 minutes. After stopping the stirring and allowing the mixture to stand for 5 minutes, about 200 g of the supernatant liquid was extracted and removed, and then 250 g of a 2% by mass lauric acid isopropanol solution was added, followed by stirring at 30° C. for 30 minutes.
After the stirring was completed, copper particles were removed by vacuum filtration using a Kiriyama funnel made of 5C filter paper. The obtained copper particles were dried under reduced pressure at 25° C. for 3 hours to obtain surface-coated copper particles (1) (copper particles (1)).

[Synthesis example 5]
(Copper particles (2): Production of surface-coated copper particles (2))
Same as Synthesis Example 1 except that copper particle a was changed to copper particle b [Mitsui Metal Mining Co., Ltd. "1400YP"; particle size (D50) 6 μm, BET specific surface area 0.60 m ² /g, shape: plate-like] In the same manner, surface-coated copper particles (2) (copper particles (2)) were obtained.

[Example 1]
(Manufacture of conductive composition)
1.0 g of lauric acid as component (a), 1.0 g of (b1) tris[3-(trimethoxysilyl)methyl] isocyanurate as component (b), and surface-coated copper particles (copper particles) as component (c). (1)), 28.0 g of surface-coated copper particles (copper particles (2)), and other ingredients, resol type phenolic resin [PL-5208, manufactured by Gunei Chemical Industry Co., Ltd., solid content 60 % by mass, solvent: diethylene glycol monoethyl ether], 15.0 g (9.0 g as solid content), 1.0 g of N,N'-bis(salicylidene)ethylenediamine, and 5.0 g of terpineol were mixed. Next, using a planetary mixer [ARV-310, manufactured by Shinky Co., Ltd.], the mixture was stirred at room temperature for 60 seconds at a rotation speed of 2000 rpm to perform primary kneading. Next, secondary kneading was performed using a three-roll mill [EXAKT-M80S, manufactured by Nagase Screen Printing Institute Co., Ltd.] by passing the mixture through the mixture five times at room temperature and with a distance between the rolls of 5 μm. The kneaded material obtained in the secondary kneading was degassed and kneaded by stirring for 90 seconds at room temperature and vacuum at a rotation speed of 1000 rpm using a planetary mixer [ARV-310, manufactured by Shinky Co., Ltd.] to make it conductive. A composition was produced. Table 2 shows the blending ratio of each component of the conductive composition.

<Evaluation of conductivity (volume resistivity)>
(Formation of linear pattern)
The obtained conductive composition was applied onto a glass substrate using a metal mask in a pattern of width x length x thickness = 1.0 mm x 30 mm x 50 μm. A cured film was prepared by heating the glass substrate coated with the conductive composition at 150° C. for 30 minutes in a convection oven.

(Formation of planar pattern)
The obtained conductive composition was applied onto a glass substrate using a metal mask in a pattern of width x length x thickness = 30 mm x 30 mm x 50 μm. A cured film was prepared by heating the glass substrate coated with the conductive composition at 150° C. for 30 minutes in a convection oven.

(Evaluation method of volume resistivity)
The conductivity of the cured film obtained by the above method was evaluated by the following method. The volume resistivity of the cured film was measured by pressing the measurement probe of a low resistivity meter [Lorestar GP MCP-T610, manufactured by Nitto Seiko Analytech Co., Ltd.] against the formed pattern, and judged according to the following evaluation criteria. . The smaller the measured value of the volume resistivity, the easier the current flows through the cured film, indicating that the cured film has better conductivity.
◎: Volume resistivity is less than 30 μΩ·cm.
○: Volume resistivity is 30 μΩ·cm or more and less than 50 μΩ·cm.
Δ: Volume resistivity is 50 μΩ·cm or more and less than 70 μΩ·cm.
×: Volume resistivity is 70 μΩ·cm or more.

<Evaluation of high temperature and high humidity resistance>
(Evaluation method for high temperature and high humidity resistance)
The cured film of the planar pattern used in the above conductivity evaluation was used as a measurement sample for the high temperature and high humidity test. The measurement sample was put into a small environmental tester [SH-242, manufactured by ESPEC Co., Ltd.], and after being stored at 60° C. and 90% RH for 240 hours, the measurement sample was taken out.

The conductivity of the cured film after the test was evaluated by the following method. The volume resistivity of the cured film was measured by pressing the measurement probe of a low resistivity meter [Lorestar GP MCP-T610, manufactured by Nitto Seiko Analytech Co., Ltd.] against the planar pattern, and the rate of change in volume resistivity was measured. It was calculated using the following formula (I) and judged according to the following evaluation criteria. In this test, the closer the value of the volume resistivity change rate is to 100%, the better the high temperature and high humidity resistance of the cured film is. In addition, the value of the above-mentioned "evaluation of conductivity" was used for the volume resistivity before the test.

Volume resistivity change rate (%)
= (Volume resistivity after test) / (Volume resistivity before test) x 100 (I)

◎: Volume resistivity change rate is less than 120%.
○: Volume resistivity change rate is 120% or more and less than 140%.
Δ: Volume resistivity change rate is 140% or more and less than 160%.
×: Volume resistivity change rate is 160% or more.

[Examples 2-7, Comparative Examples 1-2]
A conductive composition was produced and a cured film was formed in the same manner as in Example 1, except that the blending ratio of each component was as shown in Table 2. Furthermore, for each cured film, the volume resistivity of the linear pattern and planar pattern and high temperature and high humidity resistance were evaluated in the same manner as in Example 1.

The above results are shown in Table 2. In addition, the content of the phenol resin in Table 2 is the solid content equivalent amount.

The following can be seen from Table 2.
In Examples 1 to 7, the volume resistivity of the cured film was less than 50 μΩ·cm in both the linear pattern and the planar pattern, and the rate of change in volume resistivity before and after the high temperature and high humidity test was less than 140%.
On the other hand, in Comparative Example 1 in which a conductive composition was prepared without blending component (b), the volume resistivity of the linear pattern was less than 50 μΩ·cm, but the volume resistivity of the planar pattern was high at 70 μΩ·cm or more, and the volume resistivity change rate before and after the high temperature and high humidity test was high at 160% or more.
In Comparative Example 2, in which a conductive composition was prepared using tris(2,3-epoxypropyl) isocyanurate as component (b)' instead of component (b), the volume resistivity of the linear pattern was 50 μΩ. -cm, but the volume resistivity of the planar pattern was as high as 50 μΩ·cm or more, and the volume resistivity change rate before and after the high temperature and high humidity test was as high as 160% or more.

As described above, the cured film of the conductive composition containing predetermined components (a) to (c) in a predetermined ratio has good volume resistivity in both linear and planar patterns, and It can be seen that it is suitable as a circuit forming material with excellent conductivity because it has good high temperature and high humidity resistance when formed into a film.

Claims (1)

(a) aliphatic monocarboxylic acid having 8 to 18 carbon atoms;
(b) containing an isocyanuric acid derivative represented by formula (1); and (c) conductive particles;
With respect to the total of 100% by mass of components (a) to (c), the content of component (a) is 0.05 to 10% by mass, the content of component (b) is 0.05 to 10% by mass, and the component A conductive composition in which the content of (c) is 80 to 99.9% by mass.

[In formula (1), k, m, and n are integers of 1 to 3, and R ¹ to R ⁹ are each independently a methyl group or an ethyl group. ]