conductive components

Abstract

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

Description

[Technical Field]

[0001] This invention relates to a conductive composition. [Background technology]

[0002] In recent years, from the perspective of the Sustainable Development Goals (SDGs), there has been a shift in the methods of forming electronic component circuits from the conventional wet etching method, which uses large amounts of chemicals, to printing methods using screen printing machines. Within this context, there is active research into circuit formation using screen printing machines, a versatile printing method, and development is underway to create conductive paste compositions suitable for screen printing.

[0003] One of the advantages of circuit formation using screen printing is that it is possible to form linear printed patterns with a line width of about 0.1 mm to 1.0 mm and planar printed patterns with sides of several mm to tens of mm in length at the same time, thus offering a high degree of freedom in circuit design. For example, Patent Document 1 discloses a specific conductive paste (conductive resin composition) containing a saturated copolymer polyester resin that can form a stable pattern with high precision by screen printing and can obtain a cured film with excellent conductivity by heating. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-170510 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, while the conductive paste disclosed in Patent Document 1 above exhibits excellent printability and conductivity for linear patterns with a line width of approximately 1 mm, when printing planar patterns, the solvent components contained in the conductive paste may not volatilize easily from within the solid film after heating, potentially leading to an increase in insulating components in the cured film and a deterioration in conductivity. Furthermore, if solvent volatilization from within the planar pattern is difficult, the proportion of solvent that volatilizes after the binder resin contained in the conductive paste hardens increases, making it easier for fine voids to form in the cured film. Therefore, there is a risk of deterioration in conductivity when the cured film is subjected to high-temperature and high-humidity testing.

[0006] The problem that the present invention aims to solve is to provide a conductive composition that makes it possible to obtain a cured film having excellent conductivity equivalent to that of a linear pattern when a planar pattern is printed by screen printing, and that the obtained cured film has good resistance to high temperatures and high humidity. [Means for solving the problem]

[0007] As a result of repeated studies to solve the above problems, the present inventors have found that by combining conductive particles and aliphatic monocarboxylic acid with an isocyanuric acid derivative containing a specific structure, they can provide a conductive composition that can solve the above problems, and have completed the present invention.

[0008] In other words, the present invention relates to a conductive composition containing (a) an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (b) an isocyanuric acid derivative represented by formula (1), and (c) conductive particles, wherein, based on a 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 content of component (c) is 80 to 99.9% by mass.

[0009] [ka]

[0010] [In equation (1), k, m, and n are integers from 1 to 3, and R 1 ~R9 is independently either a methyl group or an ethyl group.

Advantages of the Invention

[0011] When the conductive composition of the present invention is used to print 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 for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described. In this specification, a 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. Further, when a concentration or amount is specified, any higher concentration or amount can be associated with any lower concentration or amount. For example, when there are descriptions of "2~10 mass%" and "preferably 4~8 mass%", descriptions of "2~4 mass%", "2~8 mass%", "4~10 mass%", and "8~10 mass%" are also included.

[0013] The conductive composition according to an embodiment of 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 with respect to 100% by mass in total of components (a) to (c), the content rate of component (a) is 0.05 to 10% by mass, the content rate of component (b) is 0.05 to 10% by mass, and the content rate of component (c) is 80 to 99.9% by mass.

[0014]

Chemical formula

[0015] [In formula (1), k, m, and n are integers from 1 to 3, and R 1 ~R 9 is independently either a methyl group or an ethyl group.

[0016] The following describes each component.

[0017] 〔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 the aliphatic monocarboxylic acid include linear saturated aliphatic monocarboxylic acids, linear unsaturated aliphatic monocarboxylic acids, branched saturated aliphatic monocarboxylic acids, and branched unsaturated aliphatic monocarboxylic acids. One kind selected from the above compounds can be used alone, or two or more kinds can be used in combination.

[0018] Examples of the linear saturated aliphatic monocarboxylic acid 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, stearic acid, and the like. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include myristoleic acid, palmitoleic acid, petroselinic acid, oleic acid, and the like. Examples of the branched saturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include 2-ethylhexanoic acid and the like.

[0019] From the viewpoint of conductivity, as component (a), an aliphatic monocarboxylic acid having 8 to 16 carbon atoms is preferable, and those having 8 to 12 carbon atoms are more preferable.

[0020] The content of component (a) is 0.05 to 10% by mass, preferably 0.05 to 5% by mass, based on 100% by mass of the total of components (a) to (c). When 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.

[0021] 〔Component (b) isocyanuric acid derivative represented by formula (1)〕 Component (b) used in the present invention is an isocyanuric acid derivative represented by the aforementioned formula (1).

[0022] In formula (1), R 1 ~R 9 may each independently be either a methyl group or an ethyl group, but R 1 ~R 3 , R 4 ~R 6 , R 7 ~R 9 are preferably the same, and it is more preferable that all of R 1 ~R 9 are the same. Also, k, m, and n may each independently be an integer from 1 to 3, but it is preferable that they be the same number.

[0023] Examples of component (b) include tris(isocyanurate) [( (trimethoxysilyl)methyl], tris(isocyanurate) 2 (trimethoxysilyl)ethyl], tris(isocyanurate)[3-(trimethoxysilyl)propyl], tris(isocyanurate) [( (triethoxysilyl)methyl], tris(isocyanurate) 2 (triethoxysilyl)ethyl], tris(isocyanurate)[3-(triethoxysilyl)propyl], tris(isocyanurate) [( (dimethoxyethoxysilyl)methyl], tris(isocyanurate) [( (diethoxymethoxysilyl)methyl], tris(isocyanurate) 2 (dimethoxyethoxysilyl)ethyl], tris(isocyanurate) 2 (diethoxymethoxysilyl)ethyl], tris(isocyanurate)[3-(dimethoxyethoxysilyl)propyl], tris(isocyanurate)[3-(diethoxymethoxysilyl)propyl], and the like.

[0024] One of the compounds represented by formula (1) can be used alone, or two or more can be used in combination. In particular, it is preferable to select one or more from tris[3-(trimethoxysilyl)propyl] isocyanurate and tris[3-(triethoxysilyl)propyl] isocyanurate from the viewpoint of conductivity and resistance to high temperature and high humidity, with tris[3-(trimethoxysilyl)propyl] isocyanurate being more preferable from the viewpoint of conductivity.

[0025] The content of component (b) is 0.05 to 10% by mass, preferably 0.05 to 5% by mass, relative to 100% by mass of the total of components (a) to (c). If 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.

[0026] Component (b) can be produced by known methods such as the condensation reaction of isocyanate groups, but it is also available commercially. Examples of commercially available products include, but are not limited to, KBM-9659 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0027] [Component (c): Conductive particles] Component (c) is a conductive particle, and inorganic conductive particles such as copper particles can be used. The copper particles may consist only of copper, but may also contain other metals, metal oxides, or metal sulfides other than copper, such as silver or platinum. If the copper particles further contain other metals, metal oxides, or metal sulfides other than copper, it is preferable that the mass ratio of copper in the copper particles be 50% by mass or more. The copper particles may also have a surface layer or protrusions formed on them.

[0028] While commercially available conductive particles may be used as is, it is preferable to use surface-coated conductive particles to improve oxidation resistance and other properties. In particular, it is preferable to use surface-coated conductive particles whose surfaces are coated with an amine compound, and it is even more preferable to use surface-coated conductive particles whose surfaces are coated with an amine compound represented by the following formula (2).

[0029] [ka]

[0030] (In equation (2), m is an integer between 0 and 3, and n is an integer between 0 and 2. When n=0, m is one of 0 to 3, and when n=1 or n=2, m is one of 1 to 3.)

[0031] Surface-coated conductive particles coated with an amine compound, such as the amine compound represented by formula (2) above, are preferably further coated with an aliphatic monocarboxylic acid from the viewpoint of obtaining better oxidation resistance.

[0032] As a result, the surface of the conductive particles is coated with a first coating layer formed of an amine compound and a second coating layer formed of an aliphatic monocarboxylic acid. Preferably, the first coating layer is formed on the surface of the conductive particles, and the second coating layer is formed on top of the first coating layer.

[0033] As the aliphatic monocarboxylic acid forming the second coating layer, an aliphatic monocarboxylic acid having 8 to 24 carbon atoms is preferred. Examples of such 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, stearic acid, nonadecylic acid, and arachidic acid. Examples of linear unsaturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include myristoleic acid, palmitoleic acid, petroseric acid, and oleic acid. Examples of branched saturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include 2-ethylhexanoic acid. One of the above aliphatic monocarboxylic acids can be used alone or two or more can be used in combination.

[0034] The method for producing surface-coated conductive particles is not particularly limited. Methods for obtaining surface-coated conductive particles with a surface coated with an amine compound include, for example, washing conductive particles with, for example, an aqueous solution of ammonium chloride, then adding the washed conductive particles to a solution of the amine compound and heating as necessary, or adding conductive particles to a solution containing, for example, ammonium chloride and an amine compound and heating as necessary.

[0035] One 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 is to add surface-coated conductive particles coated with an amine compound to a solution of an aliphatic monocarboxylic acid. After adding the particles to the solution of the aliphatic monocarboxylic acid, heating may be performed as needed.

[0036] The average particle size (D50) of the conductive particles is not particularly limited, but in order to enable good printing of the conductive composition containing conductive particles as component (c) in various printing methods such as dispenser printing and screen printing, it is preferable to control the average particle size (D50) of the conductive particles. Specifically, the average particle size (D50) of the conductive particles is preferably 5 nm to 20 μm, and more preferably 10 nm to 10 μm.

[0037] The average particle size (D50) of conductive particles can be measured using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3000II, manufactured by Microtrac-Bell Co., Ltd.).

[0038] Furthermore, the BET specific surface area of ​​conductive particles ranges from 0.05 to 400 m². 2 It is preferably / g, and 0.1 to 200m 2 It is more preferable that the value is / g. The BET specific surface area of ​​the conductive particles can be measured using the BET single-point method with a specific surface area measuring device (Yuasa Ionics Co., Ltd., Monosorb).

[0039] There are no particular restrictions on the shape or aspect ratio (ratio of the major axis to the minor axis of the particle) of the conductive particles, and various shapes such as spherical, polyhedral, flattened, plate-like, flake-like, flaky, rod-like, dendritic, and fibrous can be used. Conductive particles can be selected from those with different constituent components, average particle size, shape, aspect ratio, etc., and used individually or in combination of two or more types.

[0040] The content of component (c) is 80 to 99.9% by mass relative to 100% by mass of the total of components (a) to (c). The lower limit of the content of component (c) is preferably 85% by mass, and more preferably 90% by mass.

[0041] [Other ingredients] In addition to the components (a) to (c) described above, the conductive composition may contain various additives such as binder resins, solvents, antioxidants, lubricants, leveling agents, dispersants, curing agents, curing accelerators, viscosity modifiers, foaming agents, and defoaming agents, to the extent that they do not impair the effects of the present invention. Furthermore, the conductive composition may contain impurities that may inevitably be mixed in from the raw materials and the equipment used in the manufacturing process. If any of these components are included, the total amount can be more than 0 parts by mass and no more than 70 parts by mass, and preferably 50 parts by mass or less, based on the total content of (a) to (c) per 100 parts by mass.

[0042] (Binder resin) The conductive composition may contain a binder resin to adjust its film-forming properties and viscosity. The binder resin can be a known binder resin used in conductive compositions, and examples include thermosetting resins, photocurable resins, and thermoplastic resins that harden upon heating or light irradiation.

[0043] 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, and diallyl phthalate resins. Examples of photocurable resins include acrylic resins, imide resins, urethane resins, and oxetane resins. Examples of thermoplastic resins include, but are not limited to, polyamides, polyolefin resins such as polyethylene terephthalate and polyethylene, and acrylonitrile-butadiene-styrene copolymer resins. Binder resins can be used individually or in mixtures of two or more. The mixing ratio when two or more are mixed is not particularly limited. Preferably, one or more binder resins selected from the thermosetting resins epoxy resins, phenolic resins, and polyvinylphenol resins are used. The mixing ratio when two or more of these binder resins are mixed is also not particularly limited.

[0044] If the conductive composition contains a binder resin, the binder resin content is preferably 0.5 to 50 parts by mass, and more preferably 1 to 30 parts by mass, based on the solid content, per 100 parts by mass of the total content of components (a) to (c).

[0045] (solvent) The conductive composition may contain a solvent for the purpose of improving coating properties or adjusting viscosity.

[0046] Examples of solvents include, but are not limited to, ether-based alcohols such as 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, triethylene glycol monomethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol, and dipropylene glycol; non-ether-based alcohols such as propylene glycol and 1,4-butanediol; esters such as cyclohexanol acetate, methyl methoxypropionate, ethyl ethoxypropionate, and 1,6-hexanediol acetate; ketones such as isophorone and cyclohexanone; terpenes such as terpineol, dihydroterpineol, dihydroterpinyl acetate, and isobornylcyclohexanol; and other hydrocarbons such as octane, decane, dodecane, tetradecane, hexadecane, and propylene carbonate. Solvents can be used individually or in mixtures of two or more. There are no particular restrictions on the mixing ratio when mixing two or more solvents.

[0047] As for the type of solvent, it is preferable to use one or more selected from the above-mentioned ether alcohols, esters, and terpenes. The mixing ratio when two or more of these solvents are mixed is not particularly limited.

[0048] If the conductive composition contains a solvent, the solvent content is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, based on 100 parts by mass of the total content of components (a) to (c).

[0049] (Antioxidant) Conductive compositions may contain antioxidants to maintain the performance of each component during storage. There are no particular restrictions on the type of antioxidant; various antioxidants can be used depending on the application. For example, nitrogen-containing heterocyclic compounds such as 2,2-bipyridyl and 1,10-phenanthroline; Schiff bases such as N,N'-bis(salicylidene)ethylenediamine, N,N'-bis(salicylidene)-1,2-propanediamine, N,N'-bis(salicylidene)-1,3-propanediamine, and N,N'-bis(salicylidene)-1,2-phenylenediamine; 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, and N,N-dimethyl-1,4-phenylenediamine. Examples of antioxidants include, but are not limited to, aromatic diamines such as mine, N,N,N'N'-tetramethyl-1,4-phenylenediamine, and N,N'-diphenyl-1,4-phenylenediamine; phenols such as p-methoxyphenol, hydroquinone, tert-butylhydroquinone, dibutylhydroxytoluene, catechol, 4-tert-butylcatechol, pyrogallol, eugenol, and propyl gallate; and ascorbic acids such as L-ascorbic acid, 6-O-palmitoyl-L-ascorbic acid, 6-O-stearoyl-L-ascorbic acid, and tetra-2-hexyldecanoate ascorbyl. Antioxidants may be used individually or in combination of two or more. The mixing ratio when two or more are mixed is not particularly limited.

[0050] As for the type of antioxidant, it is preferable to use one or more selected from the nitrogen-containing heterocyclic compounds 2,2-bipyridyl, the Schiff bases N,N'-bis(salicylidene)ethylenediamine and N,N'-bis(salicylidene)-1,2-propanediamine, the aromatic diamines 1,2-phenylenediamine, 1,3-phenylenediamine and 1,4-phenylenediamine, the phenols p-methoxyphenol, hydroquinone and tert-butylhydroquinone, and the ascorbic acids 6-O-palmitoyl-L-ascorbic acid and 6-O-stearoyl-L-ascorbic acid. The mixing ratio when two or more of these antioxidants are mixed is not particularly limited.

[0051] If the conductive composition contains an antioxidant, the antioxidant content is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the total content of components (a) to (c).

[0052] The aforementioned conductive composition can be obtained by blending predetermined amounts of each of the aforementioned components and kneading them according to a standard method. Furthermore, a cured film can be obtained by printing a desired pattern onto a substrate surface using the conductive composition by screen printing or other methods according to a standard method, followed by heat treatment. Moreover, because the conductive composition contains the predetermined component composition described above, the cured film can have equally excellent conductivity for both the planar and linear patterns formed by screen printing, enabling the simultaneous formation of linear and planar patterns by screen printing. The resulting cured film also exhibits good resistance to high temperatures and humidity. Therefore, the aforementioned conductive composition is suitable for circuit formation by screen printing, i.e., for screen printing applications. The conductivity and resistance to high temperatures and humidity of the cured film of the conductive composition can be evaluated, for example, by the method described in the Examples section below. [Examples]

[0053] Embodiments of the present invention will be described in more detail below with reference to examples and comparative examples.

[0054] The components used in the examples and comparative examples are listed below. The physical properties of each component were measured using the methods described herein.

[0055] [Component (a): Aliphatic monocarboxylic acid with 8 to 18 carbon atoms] • 2-ethylhexanoic acid (a branched saturated aliphatic monocarboxylic acid with 8 carbon atoms) • Lauric acid (a linear saturated aliphatic monocarboxylic acid with 12 carbon atoms) • Stearic acid (a linear saturated aliphatic monocarboxylic acid with 18 carbon atoms)

[0056] [Component (b): Isocyanuric acid derivative represented by formula (1)] (b1): Trisyl isocyanurate [( [trimethoxysilyl)methyl] (see synthesis example 1 below) (b2): Tris isocyanurate [ 2 -(trimethoxysilyl)ethyl] (see 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 (see synthesis example 3 below)

[0057] [Component (b'): An isocyanuric acid derivative different from component (b)] (b5): Tris(2,3-epoxypropyl) isocyanurate (TEPIC®-G, manufactured by Nissan Chemical Industries, Ltd.)

[0058] Table 1 shows the relationship between isocyanuric acid derivatives b1 to b5 and the structure of formula (1).

[0059] [Table 1]

[0060] [Component (c): Conductive particles] • Copper particles (1): Spherical copper particles [Surface-coated copper particles (1), the manufacturing method is shown in Synthesis Example 4 below.] • Copper particles (2): Plate-shaped copper particles [Surface-coated copper particles (2), the manufacturing method is shown in Synthesis Example 5 below.]

[0061] [Other ingredients] (Binder resin) • Resol-type phenolic resin [PL-5208, manufactured by Gun-ei Chemical Industry Co., Ltd., solids content 60.0% by mass, solvent: diethylene glycol monoethyl ether] (Antioxidant) ·N,N'-bis(salicylidene)ethylenediamine (solvent) • Terpineol

[0062] [Synthesis Example 1] (b1: Tris isocyanurate) [( (Production of trimethoxysilyl(methyl)) In the reaction vessel, add 200 g of dimethyl sulfoxide and isocyanide. acid( 200 g of trimethoxysilyl)methyl and 1 g of sodium methoxide were mixed and stirred at 100°C for 6 hours, after which the reaction mixture was cooled to 20°C. Stirring was performed using a mechanical stirrer at a rotation speed of 100 rpm. Insoluble substances in the reaction mixture were filtered off by vacuum filtration of the reaction mixture using 5A filter paper. The filtered reaction mixture was concentrated under vacuum at 150°C to obtain the target product, tris(Isocyanurate)methyl [( [trimethoxysilyl)methyl] was obtained.

[0063] [Synthesis Example 2] (b2: Tris isocyanurate [ 2 (Production of [trimethoxysilyl]ethyl) Isocyanine acid( Trimethoxysilyl(methyl) isocyanate 2 Except for changing to -(trimethoxysilyl)ethyl, the synthesis was carried out in the same manner as in Synthesis Example 1, using tris isocyanurate [ 2 -(trimethoxysilyl)ethyl] was obtained.

[0064] [Synthesis Example 3] (b4: Manufacturing of tris[3-(triethoxysilyl)propyl] isocyanurate) Isocyanine acid( Tris[3-(triethoxysilyl)propyl] isocyanurate was obtained in the same manner as in Synthesis Example 1, except that trimethoxysilyl)methyl was replaced with 3-(triethoxysilyl)propyl isocyanate.

[0065] [Synthesis Example 4] (Copper particles (1): Manufacturing of surface-coated copper particles (1)) An aqueous solution of ammonium chloride was prepared by dissolving 5 g of ammonium chloride in 100 g of water. Copper particles a [Mitsui Mining & Smelting Co., Ltd. "1200Y"; particle size (D50) 2 μm, BET specific surface area 0.40 m²] 2 50 g of [spherical shape] was added to an aqueous solution of ammonium chloride and stirred at 30°C for 60 minutes under nitrogen bubbling. Stirring was performed using a mechanical stirrer at a rotation speed of 150 rpm. Stirring was then performed using the same stirring device at the same rotation speed. After stirring, the copper particles were filtered off 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. Washed copper particles were added to 250 g of a 40% by mass diethylenetriamine aqueous solution, and the mixture was heated and stirred at 60°C for 1 hour while bubbling with nitrogen. After stopping the stirring and allowing it to stand for 5 minutes, approximately 200g of the supernatant was removed. Next, 200g of isopropanol was added to the precipitate as a washing solvent, and the mixture was stirred at 30°C for 3 minutes. After stopping the stirring and allowing it to stand for 5 minutes, approximately 200g of the supernatant was removed, and then 250g of a 2% by mass isopropanol laurate solution was added, followed by stirring at 30°C for 30 minutes. After stirring was complete, the copper particles were filtered off 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)).

[0066] [Synthesis Example 5] (Copper particles (2): Manufacturing of surface-coated copper particles (2)) Copper particle a is compared to copper particle b [Mitsui Mining & Smelting Co., Ltd. "1400YP"; particle size (D50) 6 μm, BET specific surface area 0.60 m²].2 Surface-coated copper particles (2) (copper particles (2)) were obtained in the same manner as in Synthesis Example 1, except that the weight ( / g) and shape (plate-like) were changed.

[0067] [Example 1] (Manufacturing of conductive compositions) Component (a) is 1.0 g of lauric acid, and component (b) is (b1) tris(Isocyanurate). [( 1.0 g of trimethoxysilyl(methyl)methyl, 70.0 g of surface-coated copper particles (copper particle (1)) and 28.0 g of surface-coated copper particles (copper particle (2)) as component (c), and as other components, 15.0 g (9.0 g as solids) of resol-type phenolic resin [PL-5208, manufactured by Gun-ei Chemical Industry Co., Ltd., solids content 60% by mass, solvent: diethylene glycol monoethyl ether], 1.0 g of N,N'-bis(salicylidene)ethylenediamine, and 5.0 g of terpineol were mixed. Next, primary kneading was performed using a planetary mixer [ARV-310, manufactured by Shinki Co., Ltd.] at room temperature and a rotation speed of 2000 rpm for 60 seconds. Next, secondary kneading was performed using a three-roll mill [EXAKT-M80S, manufactured by Nagase Screen Printing Laboratory Co., Ltd.] by passing the mixture through it 5 times under conditions of room temperature and a roll distance of 5 μm. The compound obtained from secondary mixing was mixed and degassed for 90 seconds at room temperature and under vacuum conditions using a planetary mixer [ARV-310, manufactured by Thinky Co., Ltd.] to produce a conductive composition. The mixing ratios of each component of the conductive composition are shown in Table 2.

[0068] <Evaluation of conductivity (volume resistivity)> (Formation of linear patterns) The obtained conductive composition was applied to a glass substrate using a metal mask to create a pattern with dimensions of width × length × thickness = 1.0 mm × 30 mm × 50 μm. A cured film was prepared by heating the glass substrate coated with the conductive composition in a convection oven at 150°C for 30 minutes.

[0069] (Formation of planar patterns) The obtained conductive composition was applied to a glass substrate using a metal mask to create a pattern with dimensions of width × length × thickness = 30 mm × 30 mm × 50 μm. A cured film was prepared by heating the glass substrate coated with the conductive composition in a convection oven at 150°C for 30 minutes.

[0070] (Method for evaluating volume resistivity) The conductivity of the cured film obtained by the above method was evaluated using the following method. The volume resistivity of the cured film was measured by pressing the measurement probe of a low resistivity meter [Loresta-GP MCP-T610, manufactured by Nitto Seikou Analytech Co., Ltd.] against the formed pattern, and was judged according to the evaluation criteria below. A smaller volume resistivity measurement indicates that current flows easily through the cured film and that it has superior conductivity. ◎: Volume resistivity is less than 30 μΩ·cm. ○: The volume resistivity is 30 μΩ·cm or more and less than 50 μΩ·cm. △: Volume resistivity is 50 μΩ·cm or more and less than 70 μΩ·cm. ×: The volume resistivity is 70 μΩ·cm or higher.

[0071] <Evaluation of resistance to high temperature and high humidity> (Method for evaluating resistance to high temperature and high humidity) The cured film of the planar pattern used in the conductivity evaluation described above was used as the measurement sample for the high-temperature, high-humidity test. The measurement sample was placed in a small environmental testing machine [SH-242, manufactured by ESPEC Corporation] and stored at 60°C and 90% RH for 240 hours before being removed.

[0072] The conductivity of the cured film after the test was evaluated using the following method. The volume resistivity of the cured film was measured by pressing the measuring probe of a low resistivity meter [Loresta-GP MCP-T610, manufactured by Nitto Seikou Analytech Co., Ltd.] against the planar pattern. The rate of change of volume resistivity was calculated using the following formula (I) and judged according to the evaluation criteria below. In this test, the closer the value of the rate of change of volume resistivity is to 100%, the better the high temperature and high humidity resistance of the cured film. The volume resistivity before the test was the value used in the "Evaluation of Conductivity" described above.

[0073] Volume resistivity change rate (%) = (Volume resistivity after testing) / (Volume resistivity before testing) × 100 (I)

[0074] ◎: The rate of change in volume resistivity is less than 120%. ○: The rate of change in volume resistivity is 120% or more and less than 140%. △: The rate of change in volume resistivity is 140% or more and less than 160%. ×: The rate of change in volume resistivity is 160% or more.

[0075] [Examples 2-7, Comparative Examples 1-2] The conductive composition was manufactured and the cured film formed in the same manner as in Example 1, except that the mixing ratios of each component were as shown in Table 2. Furthermore, for each cured film, the volume resistivity of the linear and planar patterns, as well as the resistance to high temperature and high humidity, were evaluated in the same manner as in Example 1.

[0076] The results are shown in Table 2. Note that the phenol resin content in Table 2 is expressed on a solids basis.

[0077] [Table 2]

[0078] From Table 2, the following can be seen. In Examples 1 to 7, the volume resistivity of the cured film was less than 50 μΩ·cm for both the linear and planar patterns, and the rate of change in volume resistivity before and after the high-temperature and high-humidity test was less than 140%. In contrast, in Comparative Example 1, in which the conductive composition was prepared without incorporating 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 rate of change in volume resistivity before and after the high temperature and high humidity test was high at 160% or more. Furthermore, 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 less than 50 μΩ·cm, but the volume resistivity of the planar pattern was high at 50 μΩ·cm or more, and the rate of change in volume resistivity before and after the high temperature and high humidity test was high at 160% or more.

[0079] As described above, the cured film of a conductive composition containing the predetermined components (a) to (c) in predetermined ratios exhibits good volume resistivity in both linear and planar patterns, and also exhibits good resistance to high temperatures and humidity when cured. Therefore, it is clear that it is suitable as a circuit-forming material with excellent conductivity.

Claims

[Claim 1] (a) Aliphatic monocarboxylic acids having 8 to 18 carbon atoms, (b) Isocyanuric acid derivative represented by formula (1), (c) conductive particles, and (d) Contains a resol-type phenolic resin as the binder resin, With respect to a 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 content of component (c) is 80 to 99.9% by mass. A conductive composition in which the content of component (d) is 0.5 to 50 parts by mass per 100 parts by mass of the total of components (a) to (c). 【Chemistry 1】 [In equation (1), k, m, and n are integers from 1 to 3, and R １ ~R ９ These are, independently, either a methyl group or an ethyl group.

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