KR20220025669A - Conductive composition - Google Patents

Abstract

The present invention provides a conductive composition excellent in printability and conductivity because, when printing is resumed after the printing is stopped for a certain period of time, the line width of a wiring pattern or the viscosity of a composition is difficult to be changed before and after the printing is resumed. Provided is a conductive composition containing (a) 0.1 to 5 mass% of polyethylene glycol having an average molecular weight of 200 to 2,000, (b) 0.1 to 5 mass% of an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (c) 60 to 95 mass% of conductive particles, and (d) 1 to 30 mass% of a binder resin.

Description

Conductive composition {CONDUCTIVE COMPOSITION}

The present invention relates to a conductive composition that can maintain a wet state for a long time when the composition before heating is left still, and is excellent in printability and conductivity.

In recent years, with increasing awareness of safety and the environment, there is a demand to reduce the amount of chemical liquid that affects the human body or the environment. Also in the wiring forming method of an electronic component, the conventional wet etching method using a large amount of chemical liquid is replaced with the printing method using comparatively little chemical liquid. Among them, development of wiring forming technology using a screen printing machine, a general-purpose printing method, is being actively developed, and research and development of a conductive paste suitable for screen printing as a material is being conducted. The conductive paste is required to have various properties necessary for the development of a target product, such as its conductivity and adhesion to a substrate to be applied. Especially, since printability is a characteristic especially strongly requested|required from a viewpoint of productivity, the electrically conductive paste excellent in printability is strongly calculated|required. For example, Patent Document 1 discloses an electrically conductive paste that is excellent in printability for fine lines and that the line width of printing does not easily change.

In wiring formation using screen printing, an electrically conductive paste capable of printing wiring patterns of the same line width continuously for a long period of time is preferable from the viewpoint of productivity. However, in an actual manufacturing process, it frequently occurs that printing is stopped for a long time depending on work conditions such as inspection of a printed pattern or inspection of a printing machine. For example, when screen printing is performed using the conductive paste of Patent Document 1, when printing is resumed after printing is stopped for a certain period of time, clogging or conductivity of the mesh generated by drying of the conductive paste on the screen plate Due to the thickening that occurs as the solvent in the paste is volatilized, defects such as breakage occur in the wiring pattern after printing is resumed, or the line width of the wiring pattern changes significantly before and after printing is resumed.

That is, when screen printing using the conductive paste is stopped for a certain period of time, depending on the length of the stop time, the resistance value increases due to the non-uniformity of the line width of the wiring pattern, or the wire breaks due to breakage. there was a risk of it happening.

Japanese Patent Laid-Open No. 2014-67492

The problem to be solved by the present invention is to provide a conductive composition having excellent printability and conductivity because it is difficult to change the line width of the wiring pattern or the viscosity of the composition before and after printing is resumed when printing is resumed after stopping printing for a certain period of time will be.

The present inventors, as a result of repeated studies to solve the above problems, in addition to the conductive particles and the binder resin, a specific component excellent in the dispersion stability of the conductive particles, and a specific component that can maintain the wet state of the composition for a long time By mix|blending, it discovered that the electroconductive composition which can solve the said subject can be provided, and came to complete this invention.

That is, in the present invention, (a) 0.1 to 5 mass% of polyethylene glycol having an average molecular weight of 200 to 2,000, (b) 0.1 to 5 mass% of an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (c) 60 electroconductive particles It is a conductive composition containing -95 mass % and 1-30 mass % of (d) binder resin.

According to the conductive composition of the present invention, it can be used as a wiring forming material having excellent conductivity and printability, and when printing is resumed after stopping printing for a certain period of time, the line width of the wiring pattern or the viscosity of the composition before and after printing is resumed The effect that it is hard to change is acquired. Accordingly, it is possible to print a wiring pattern in which a resistance value increase or disconnection is unlikely to occur.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described.

In addition, in this specification, the numerical range prescribed|regulated using the symbol "-" shall include the numerical value of both ends (upper limit and lower limit) of "-". For example, "2-5" represents 2 or more and 5 or less.

Also, when a concentration or amount is specified, one can associate any concentration or amount on the higher side with any concentration or amount on the lower side. For example, when there is description of "2-10 mass %" and "preferably 4-8 mass %", "2-4 mass %", "2-8 mass %", "4-10 mass %" ' and "8-10 mass %" are also included.

The conductive composition of the present invention contains (a) polyethylene glycol having an average molecular weight of 200 to 2,000, (b) an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, (c) conductive particles, and (d) binder resin. Below, each component is demonstrated.

In addition, each content of the said component (a), a component (b), a component (c), and a component (d) is the sum total of each content of a component (a), a component (b), a component (c), and a component (d) It is a ratio (mass %) with respect to a value.

[Component (a): Polyethylene glycol]

Component (a) used in the present invention is polyethylene glycol, and has an average molecular weight of 200 to 2,000, preferably 400 to 1,500, more preferably 500 to 800 from the viewpoint of maintaining wettability. These may be used individually by 1 type, or may use 2 or more types together.

In addition, the average molecular weight of polyethyleneglycol can be measured by the method of calculating an average molecular weight based on the hydroxyl value measured based on JISK1557.

Content of component (a) is 0.1-5 mass %. From a viewpoint of wettability maintenance, Preferably it is 0.2-5 mass %, More preferably, it is 0.3-5 mass %, More preferably, it is 0.5-5 mass %.

On the other hand, from an electroconductive viewpoint of a cured film, Preferably it is 0.1-4 mass %, More preferably, it is 0.1-3 mass %, More preferably, it is 0.1-2 mass %.

When the content of the component (a) is too low, good wettability is difficult to be exhibited and it is difficult to maintain wettability for a long time. Moreover, when content of a component (a) is too high, the electroconductivity of an electroconductive composition may fall.

[Component (b): aliphatic monocarboxylic acid]

Component (b) used in the present invention is an aliphatic monocarboxylic acid having 8 to 18 carbon atoms. As an aliphatic monocarboxylic acid, a linear saturated aliphatic monocarboxylic acid, a linear unsaturated aliphatic monocarboxylic acid, a branched saturated aliphatic monocarboxylic acid, and a branched unsaturated aliphatic monocarboxylic acid are mentioned, for example. One type selected from the above compounds may be used alone or two or more types may be used in combination.

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, etc. are mentioned. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include myristic oleic acid, palmitoleic acid, petrocelic acid and oleic acid. Examples of the branched saturated aliphatic monocarboxylic acid having 8 to 18 carbon atoms include 2-ethylhexanoic acid.

As component (b), a C8-C18 linear saturated aliphatic monocarboxylic acid is preferable from a viewpoint of electroconductivity. Further, the linear saturated aliphatic monocarboxylic acid has more preferably 12 to 18 carbon atoms, still more preferably 12 to 14 carbon atoms, and particularly preferably 12 carbon atoms.

Content of component (b) is 0.1-5 mass %. From a viewpoint of suppressing a viscosity change, Preferably it is 0.3-5 mass %, More preferably, it is 0.5-5 mass %, More preferably, it is 1-5 mass %.

On the other hand, from an electroconductive viewpoint of a cured film, Preferably it is 0.1-4 mass %, More preferably, it is 0.1-3.5 mass %, More preferably, it is 0.1-3 mass %.

When content of a component (b) is too low, it may become easy to increase the viscosity of an electroconductive composition. Moreover, when content of a component (b) is too high, the electroconductivity of an electroconductive composition may fall.

[Component (c): Electroconductive Particles]

The component (c) used by this invention can use inorganic electroconductive particles, such as a copper particle, as electroconductive particle, for example. Although the copper particle may consist only of copper, it may contain metals other than copper, such as silver and platinum, a metal oxide, and a metal sulfide further. When a copper particle further contains metals other than copper, a metal oxide, and a metal sulfide, it is preferable that the mass ratio of copper in a copper particle shall be 50 mass % or more. Moreover, the shape in which the surface layer and protrusion were formed may be sufficient as a copper particle.

Although commercially available electroconductive particle may be used as it is, it is preferable to use the surface-coated electroconductive particle which coat|covered the surface for the purpose of oxidation resistance improvement etc. Among them, it is preferable to use surface-coated conductive particles whose surface is coated with an amine compound, and it is more preferable to use surface-coated conductive particles whose surface is coated with an amine compound represented by the following formula (1).

(in formula (1),

m is an integer from 0 to 3, n is an integer from 0 to 2,

When n = 0, m is any one of 0 to 3,

When n=1 or n=2, m is any one of 1 to 3)

The surface-coated conductive particles whose surface is coated with an amine compound such as an amine compound represented by the formula (1) are preferably surface-coated conductive particles further coated with an aliphatic monocarboxylic acid from the viewpoint of obtaining better oxidation resistance.

Accordingly, the surface of the conductive particles is coated with the first covering layer formed of the amine compound and the second covering layer formed of the aliphatic monocarboxylic acid. Preferably, the first covering layer is formed on the surface of the conductive particles, and the second covering layer is formed on the first covering layer.

As the aliphatic monocarboxylic acid forming the second coating layer, an aliphatic monocarboxylic acid having 8 to 20 carbon atoms is preferable. As said aliphatic monocarboxylic acid, a linear saturated aliphatic monocarboxylic acid, a linear unsaturated aliphatic monocarboxylic acid, a branched saturated aliphatic monocarboxylic acid, and a branched unsaturated aliphatic monocarboxylic acid are mentioned, for example.

Examples of the linear saturated aliphatic monocarboxylic acid having 8 to 20 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, arachidic acid, etc. are mentioned. Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 to 20 carbon atoms include myristoleic acid, palmitoleic acid, petrocelic acid, and oleic acid. Examples of the branched saturated aliphatic monocarboxylic acid having 8 to 20 carbon atoms include 2-ethylhexanoic acid.

As said aliphatic monocarboxylic acid, 1 type selected from the said compound can be used individually, or 2 or more types can also be used together.

For the dispersibility of the surface-coated conductive particles, it is preferable to use those having the same structure or carbon number as the aliphatic monocarboxylic acid of the component (b) to be used, or having an approximate carbon number.

A method for producing the surface-coated conductive particles is not particularly limited. As a method of obtaining surface-coated conductive particles coated with an amine compound on the surface, for example, after the conductive particles are washed with an aqueous ammonium chloride solution or the like, the cleaned conductive particles are added to a solution of an amine compound and heated as necessary. method can be found.

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, surface-coated conductive particles coated with an amine compound are mixed with an aliphatic monocarboxylic acid. The method of adding to a solution is mentioned. Moreover, after adding to the solution of an aliphatic monocarboxylic acid, you may heat as needed. The description of the conductive particles below includes surface-coated conductive particles.

The average particle diameter (D50) of the conductive particles is not particularly limited, but in order to be able to print a conductive composition containing conductive particles as component (c) satisfactorily in various printing methods such as inkjet printing and screen printing, conductive It is preferable to control the average particle diameter (D50) of the particles. Specifically, it is preferable that they are 5 nm - 20 micrometers, and, as for the average particle diameter (D50) of electroconductive particle, it is more preferable that they are 10 nm - 10 micrometers.

In addition, the average particle diameter (D50) of electroconductive particle can be measured with a laser diffraction/scattering type particle size distribution measuring apparatus (Microtrac BEL Corp., "Microtrac MT3000II").

Moreover, it is preferable that it is 0.05-400 m<2>/g, and, as for the BET specific surface area of electroconductive particle, it is more preferable that it is 0.1-200 m<2>/g.

In addition, the BET specific surface area of electroconductive particle can be measured by the BET one-point method using a specific surface area measuring apparatus (Yuasa Ionics Co., Ltd. product, "MONOSORB").

There is no particular limitation on the shape of the conductive particles or the aspect ratio (ratio of the major and minor diameters of the particles), and there is no particular limitation on the shape of the conductive particles, and the shape is spherical, polyhedral, flat, plate, or flake. A thing of various shapes, such as a flake shape, a flake shape, a rod shape, a dendritic shape, and a fiber shape, can be used. Electroconductive particle may be used individually by 1 type chosen from things from which a structural component, an average particle diameter, a shape, an aspect-ratio, etc. differ, or may use 2 or more types together.

As the conductive particles, it is preferable from the viewpoint of conductivity to use one type of conductive particle or two or more types of conductive particles selected from spherical, flat, plate, flake, flaky, and dendritic, and select from spherical, plate, and dendritic. It is more preferable to use 1 type of electroconductive particle used or 2 types of electroconductive particle. Moreover, when using together 2 types of electroconductive particle, it is preferable to use spherical electroconductive particle and plate-shaped electroconductive particle.

Mass ratio in the case of using together 2 types of spherical electroconductive particle and plate-shaped electroconductive particle is a viewpoint of the electroconductivity of the cured film obtained by heat-hardening a composition, spherical electroconductive particle:plate-shaped electroconductive particle is 1:99-99:1 It is preferable that it is 5:95-95:5, It is more preferable, It is more preferable that it is 10:90-90:10.

Content of component (c) is 60-95 mass %. The lower limit of content of component (c) becomes like this. Preferably it is 70 mass %, More preferably, it is 80 mass %. In addition, the upper limit of content of a component (c) becomes like this. Preferably it is 90 mass %.

[Component (d): Binder Resin]

The component (d) used in the present invention is a binder resin, and is a component that acts as a binder in the conductive composition of the present invention.

As component (d), well-known binder resin used for an electrically conductive paste etc. can be used, A thermosetting resin, photocurable resin, a thermoplastic resin, etc. which are hardened by heating or light irradiation can be illustrated.

Examples of the thermosetting resin include epoxy resin, melamine resin, phenol resin, silicone resin, polyurethane resin, unsaturated polyester resin, vinyl ester resin, polyvinyl phenol resin, xylene resin, acrylic resin, oxetane resin, diallyl phthalate. resin etc. are mentioned. As a photocurable resin, an acrylic resin, an imide resin, a urethane resin, etc. are mentioned, for example. Examples of the thermoplastic resin include polyolefin-based resins such as polyamide, polyethylene terephthalate, and polyethylene; Acrylonitrile-butadiene-styrene copolymer resin etc. are mentioned.

As binder resin of component (d), 1 type selected from these resins can be used individually, or 2 or more types can also be used together.

In addition, it is preferable from the viewpoint of curability to use one or more selected from the group consisting of epoxy resins, phenolic resins and polyvinylphenol resins, which are thermosetting resins, and one or two selected from epoxy resins and phenolic resins. it is more preferable

Content of component (d) is 1-30 mass %, Preferably it is 3-25 mass %, More preferably, it is 4-20 mass %, More preferably, it is 5-15 mass %. When content of component (d) is too low, it may become difficult to provide sufficient fluidity|liquidity when printing using an electrically conductive composition. When content of a component (d) is too high, it may become difficult to contact between the electroconductive particles of the component (c) in an electrically conductive composition, and it may become difficult to obtain the cured film which shows the outstanding electroconductivity.

Further, as the component (d), the mass ratio in the case of using two types of an epoxy resin and a phenol resin in combination is preferably 1:99 to 99:1, and 5:95 to 95: It is more preferable that it is 5, and it is still more preferable that it is 10:90-90:10.

[Other Ingredients]

The conductive composition of the present invention may contain a solvent, a lubricant, a leveling agent, a dispersing agent, a curing agent, a curing accelerator, and a plasticizer, if necessary, in the range that does not impair the effects of the present invention other than the above components (a) to (d). , various additives such as viscosity modifiers and foaming agents may be contained. Further, the conductive composition of the present invention may contain impurities that may be unavoidably mixed from raw material components and equipment in the manufacturing process.

(solvent)

The conductive composition of this invention may contain the solvent for the purpose of improvement of applicability|paintability, or adjustment of a viscosity.

Examples of the solvent include ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, and the like. etheric alcohols; non-ether alcohols such as propylene glycol and 1,4-butanediol; esters such as cyclohexanol acetate, methylmethoxypropionate, ethylethoxypropionate, 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.

Among these solvents, it is preferable to use one or two or more types selected from the above ether alcohols, the above esters, and the above terpenes, and it is more preferable to use one or two or more types selected from the above terpenes. desirable.

The type of solvent is not limited to the above, and depending on the purpose, one type selected from various solvents may be used alone or two or more types may be mixed and used. The mixing ratio in particular in the case of mixing 2 or more types is not restrict|limited.

When the conductive composition of the present invention contains a solvent, the content of the solvent is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the total content of components (a) to (d), more preferably 3 to 15 mass parts, More preferably, it is 4-10 mass parts.

(lubricant)

The conductive composition used by this invention can add a lubricating agent suitably for the purpose of dispersibility control of the electroconductive particle of the component (c) in a composition. The type of lubricant and its mixing ratio are not particularly limited, and one type may be used alone or two or more types may be mixed according to the use.

Examples of the lubricant include fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid; fatty acid metal salts formed from metals such as sodium, potassium, barium, magnesium, calcium, aluminum, iron, cobalt, manganese, zinc, and tin and the fatty acids; fatty acid amides such as stearic acid amide, oleic acid amide, behenic acid amide, palmitic acid amide, and lauric acid amide; fatty acid esters such as butyl stearate; waxes such as paraffin wax and liquid paraffin; alcohols such as ethylene glycol and stearyl alcohol; Polyethers comprising polyethylene glycol, polypropylene glycol, and modified products thereof; polysiloxanes such as silicone oil; and fluorine compounds such as fluorine-based oil.

Among these lubricants, one or two or more selected from fatty acids and fatty acid metal salts are preferably used, and magnesium stearate is more preferably used.

When the conductive composition of the present invention contains a lubricant, the content of the lubricant is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the total content of components (a) to (d). It is 5 mass parts, More preferably, it is 0.2-3 mass parts.

(leveling agent)

In the conductive composition used in the present invention, a leveling agent may be appropriately added for the purpose of controlling surface defects of a coating film obtained from the conductive composition. The type of the leveling agent and the mixing ratio thereof are not particularly limited, and one type may be used alone or two or more types may be mixed according to the use.

As a kind of leveling agent, For example, BYK-354, BYK-355, BYK-356, BYK-350, BYK-381, BYK-394, BYK-399, BYK-3440, BYK-3441, BYK-358N, BYK acrylic compounds such as -361N (above, BYK Japan KK, "BYK" is a registered trademark); POLYFLOW KL-400X, POLYFLOW KL-400HF, POLYFLOW KL-401, POLYFLOW KL-402, POLYFLOW KL-403, POLYFLOW KL-404, POLYFLOW KL-406X (above, Kyoeisha) silicone-based compounds such as manufactured by Kyoeisha Chemical Co., Ltd.; Mega Face F410, Mega Face F281, Mega Face F477, Mega Face F510, Mega Face F552, Mega Face F554, Mega Face F556, Mega Face F557, Mega Face F558, Mega Face F559, Mega Face F560, Mega Face F561 , Megaface F563, Megaface F569 (above, the DIC Corporation product, "Megaface" is a registered trademark), etc. are mentioned.

Among these leveling agents, it is preferable to use 1 type, or 2 or more types selected from fluorine-type compounds, and it is more preferable to use Megaface F477.

When the conductive composition of the present invention contains a leveling agent, the content of the leveling agent is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the total content of components (a) to (d). It is 0.1-5 mass parts, More preferably, it is 0.2-3 mass parts.

(dispersant)

The conductive composition used by this invention can add a dispersing agent suitably for the purpose of dispersibility control of the electroconductive particle of the component (c) in a composition. The type of dispersant and its mixing ratio are not particularly limited, and one type may be used alone or two or more types may be mixed according to the use.

As a kind of dispersing agent, For example, sarcosine compounds, such as lauroyl sarcosine, myristoyl sarcosine, palmitoyl sarcosine, stearoyl sarcosine, and oleoyl sarcosine; FILLANOL PA-075F, FILLANOL PA-085C, FILLANOL PA-107P, ESLEAM AD-3172M, ESLEAM AD-374M, ESLIM AD-508E (above, Nichiyu Co., Ltd.) NOF CORPORATION) products, and "Srim" is a registered trademark) high molecular weight amine compounds; MALIALIM AKM-0531, Mariarim AFB-1521, Mariarim AAB-0851, Mariarim AWS-0851, Mariarim SC-0505K, Mariarim SC-1015F, Mariarim SC-0708A (above, Nichiyu high molecular weight polycarboxylic acid-based compounds such as those manufactured by Shiki Corporation).

Among these dispersants, it is preferable to use 1 type or 2 or more types selected from sarcosine compounds, and it is more preferable to use oleoyl sarcosine.

When the conductive composition of the present invention contains a dispersing agent, the content of the dispersing agent is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total content of components (a) to (d). It is 5 mass parts, More preferably, it is 0.3-3 mass parts.

(Example)

Below, the manufacturing example and evaluation method of the electroconductive composition which concerns on this invention are shown. In addition, an Example and a comparative example are given and embodiment of this invention is demonstrated more concretely.

Each component used in the Example and the comparative example is shown below.

In addition, the physical property of each component is the value measured by the method described in this specification.

[Component (a): Polyethylene glycol]

PEG200 (polyethylene glycol with an average molecular weight of 200)

PEG600 (polyethylene glycol with an average molecular weight of 600)

PEG2000 (polyethylene glycol with an average molecular weight of 2,000)

PEG4000 (polyethylene glycol with an average molecular weight of 4,000)

glycerin

[Component (b): aliphatic monocarboxylic acid]

2-ethylhexanoic acid (branched saturated aliphatic monocarboxylic acid having 8 carbon atoms)

Lauric acid (a straight-chain saturated aliphatic monocarboxylic acid having 12 carbon atoms)

Stearic acid (a straight-chain saturated aliphatic monocarboxylic acid having 18 carbon atoms)

[Component (c): Electroconductive Particles]

Copper particle (1): spherical copper particle (The manufacturing method is shown to the surface-coated copper particle (1), the following synthesis example 1)

Copper particles (2): dendritic copper particles [FCC-TB, Fukuda Metal Foil & Powder Co., Ltd., particle size (D50): 5.5 to 8.0㎛]

Copper particle (3): plate-shaped copper particle (surface-coated copper particle (2), the manufacturing method is shown in the following synthesis example 2]

[Component (d): Binder Resin]

Resol type phenolic resin [PL-5208, Gun Ei Chemical Industry Co., Ltd. product, solid content 60.0 mass %, solvent: diethylene glycol monoethyl ether]

Bisphenol F-type epoxy resin [jER (registered trademark)-806, manufactured by Mitsubishi Chemical Corporation]

As other components, the following materials were used.

(lubricant)

magnesium stearate

(dispersant)

oleoyl sarcosine

(leveling agent)

Fluorine compounds [Megaface (registered trademark) F-477, manufactured by DIC Corporation]

(solvent)

terpineol

Isobornylcyclohexanol

[Synthesis Example 1]

(Copper particle (1): Preparation of surface-coated copper particle (1))

An aqueous solution of ammonium chloride in which 5 g of ammonium chloride was dissolved in 100 g of water was prepared. Copper particle (a) [Mitsui Kinzoku Kogyo Co., Ltd. (MITSUI MINING & SMELTING CO., LTD.) product "1200Y"; Particle size (D50) of 2 μm, BET specific surface area of 0.40 m 2 /g, shape: spherical] 50 g was added to the ammonium chloride aqueous solution, and stirred at 30° C. for 60 minutes under nitrogen bubbling. Stirring was performed at a rotation speed of 150 rpm using a mechanical stirrer. In the following, stirring was performed using the same stirring device at the same rotational speed. After completion of stirring, copper particles were separated by vacuum filtration using a Kiriyama funnel (KIRIYAMA ROHTO) of 5C filter paper, and then, copper particles were washed twice with 150 g of water on the Kiriyama funnel.

The wash|cleaned copper particle was added to 250 g of 40 mass % diethylene triamine aqueous solution, and it heat-stirred under 60 degreeC for 1 hour, bubbling nitrogen.

After stopping the stirring and allowing to stand for 5 minutes, about 200 g of the supernatant was taken out and removed. Next, 200 g of isopropanol was added to the precipitate as a washing solvent, and the mixture was stirred at 30°C for 3 minutes. After stopping stirring and leaving it to stand for 5 minutes, about 200 g of supernatant liquid was pulled out and removed, 250 g of 2 mass % isopropanol lauric-acid solutions were added after that, and it stirred at 30 degreeC for 30 minutes.

After completion of stirring, copper particles were separated by filtration under reduced pressure using a Kiriyama funnel of 5C filter paper. The surface-coated copper particle (1) (copper particle (1)) was obtained by drying the obtained copper particle under reduced pressure at 25 degreeC for 3 hours.

[Synthesis Example 2]

(Copper particle (3): Preparation of surface-coated copper particle (2))

Copper particle (a) to copper particle (b) [Mitsui Kinzoku Kogyo Co., Ltd. product "1400YP"; A particle size (D50) of 6 µm, BET specific surface area of 0.60 m 2 /g, shape: plate shape] was carried out in the same manner as in Synthesis Example 1 to obtain surface-coated copper particles (2) (copper particles (3)).

[Example 1]

(Preparation of conductive composition)

1.5 g of PEG200 as component (a), 1.5 g of lauric acid as component (b), 87 g of surface-coated copper particles (1) (copper particles (1)) as component (c), resol-type phenolic resin as component (d) [PL-5208, Gunei Chemical Co., Ltd. product, 60 mass % solid content, solvent: diethylene glycol monoethyl ether] 16.7 g (10 g as solid content) was mixed. Next, using a planetary mixer (ARV-310, manufactured by THINKY CORPORATION), the mixture was stirred for 60 seconds at a rotation speed of 1500 rpm at room temperature, followed by primary kneading.

Next, using a three roll mill (EXAKT-M80S, manufactured by Nagase Screen Printing Research Co., Ltd.) at room temperature, the distance between the rolls was 5 µm. Second kneading was carried out by passing it through 5 times under 8 g of terpineol (Ter) was added to the mixture obtained by the secondary kneading, and the conductive composition was prepared by degassing and kneading by adding 8 g of terpineol (Ter) and stirring for 90 seconds at a rotation speed of 1000 rpm under vacuum conditions at room temperature and vacuum using a rotating mixer.

Table 1 shows the mixing ratio of each component in the conductive composition.

(Formation of cured film)

The obtained conductive composition was apply|coated on the glass substrate using the metal mask, and the pattern of width x length x thickness = 1.0 mm x 30 mm x 50 micrometers was apply|coated. A cured film was produced by heating the glass substrate to which the conductive composition was applied in a convection oven at 250°C for 30 minutes in an atmospheric condition.

(Evaluation method of resistance value)

The following resistance value measurement evaluated the electroconductivity of the cured film obtained by said method. A measuring probe is placed on both ends of the formed pattern, and the resistance value of the cured film is measured using a digital multimeter [PC7000, manufactured by SANWA ELECTRIC INSTRUMENT CO., LTD.], It judged according to the following evaluation criteria.

Since an electric current flows easily so that the resistance value of a cured film is low, it shows that it is excellent in electroconductivity.

(double-circle): resistance value is less than 1.0 ohm.

(circle): Resistance value is 1.0 ohm or more and less than 10.0 ohm.

(triangle|delta): resistance value is 10.0 ohm or more and less than 50.0 ohm.

x: A resistance value is 50.0 ohm or more.

(Evaluation method of viscosity change rate before and after continuous printing)

The obtained conductive composition was continuously printed on PET film by 100 sheets using a screen printing machine (MT-320T, manufactured by Micro-tec Co., Ltd.).

Using a type E viscometer [TV-25, manufactured by Toki Sangyo Co., Ltd.], the viscosity of each conductive composition before and after continuous printing using a screen printing machine was measured, and the rate of change in viscosity was obtained by the following formula (I), and was determined according to the following evaluation criteria.

In this test, since the viscosity of the conductive composition is less likely to change during continuous printing as the value of the rate of change of viscosity is smaller, it indicates that the printability is stable.

Viscosity change rate (%) = [(viscosity of conductive composition after continuous printing test)/(viscosity of conductive composition before continuous printing test)] x 100 … (I)

(double-circle): The viscosity change rate is less than 110 %.

(circle): The viscosity change rate is 110 % or more and less than 150 %.

(triangle|delta): The viscosity change rate is 150 % or more and less than 200 %.

x: A viscosity change rate is 200 % or more.

(Evaluation method of line width retention before and after intermittent printing)

After printing one sheet of the obtained conductive composition on a PET film using a screen printing machine [MT-320T, manufactured by Microtech Corporation], the conductive composition was left still on a screen plate for 60 minutes, and then another One sheet was printed on PET film.

Each line width before and after printing was measured using a laser microscope [VK-9700, manufactured by KEYENCE CORPORATION], and the line width retention was obtained by the following formula (II), and it was determined according to the following evaluation criteria .

In this test, the closer the value of the line width retention ratio to 100%, the longer the wettability of the conductive composition is maintained during intermittent printing, indicating that wiring patterns can be printed stably.

Line width retention (%) = [(line width of a printed wiring pattern after standing for 60 minutes)/(line width of a printed wiring pattern when printing one sheet)] × 100 … (II)

(double-circle): Line width retention is 90 % or more and 100 % or less.

(circle): Line width retention is 70 % or more and less than 90 %.

(triangle|delta): Line width retention is 50 % or more and less than 70 %.

x: line width retention is less than 50 %.

[Examples 2-11: Comparative Examples 1-4]

In the same manner as in Example 1, except that the mixing ratio of each component was as shown in Tables 1 to 3, a conductive composition was prepared and applied to a glass substrate using a metal mask. In addition, in formation of a cured film, Examples 2-6, Examples 8-10, and Comparative Examples 1-4 heated in atmospheric atmosphere, and Example 7 and 11 heated in nitrogen atmosphere.

Moreover, about each cured film, it carried out similarly to Example 1, and evaluated the resistance value, the viscosity change rate before and behind continuous printing, and the linewidth retention before and behind intermittent printing. The results of Examples 1 to 6 are shown in Table 1, the results of Examples 7 to 11 are shown in Table 2, and the results of Comparative Examples 1 to 4 are shown in Table 3. In addition, content of the phenol resin in Tables 1-3 is a solid content conversion amount.

In Examples 1-11, all the resistance values of a cured film are less than 10.0 ohms, the viscosity change rate before and behind continuous printing is less than 150 %, and the linewidth retention before and behind intermittent printing is 70 % or more.

On the other hand, in Comparative Example 1 in which the conductive composition was prepared without mixing the component (a), the resistance value of the cured film was as high as 10.0 Ω or more, the viscosity change rate before and after continuous printing was as high as 200% or more, and the linewidth retention before and after intermittent printing was high. as low as less than 70%.

In Comparative Example 2, in which the conductive composition was prepared without mixing the component (b), the line width retention before and after intermittent printing was 70%, but the resistance value of the cured film was high as 50.0 Ω or more, and the viscosity change rate before and after continuous printing was 200% or more was high as

In Comparative Example 3, in which the conductive composition was prepared by changing the component (a) to PEG4000, the resistance value of the cured film was less than 10.0Ω, but the viscosity change rate before and after continuous printing was as high as 200% or more, and the linewidth retention before and after intermittent printing was 50% was less than

Moreover, in the comparative example 4 which changed component (a) to glycerol and prepared the electrically conductive composition, the resistance value of the cured film was as high as 85 ohms.

[Example 12]

It carried out similarly to Example 1 with the following formulation, and manufacture of the conductive composition and formation of the cured film were performed. Moreover, about each cured film, it carried out similarly to Example 1, and evaluated the resistance value, the viscosity change rate before and behind continuous printing, and the linewidth retention before and behind intermittent printing.

Component (a): PEG200 1.5g

Component (b): 1.5 g of lauric acid

Component (c) conductive particles: surface-coated copper particles (copper particles (1)) 87 g

Component (d) Binder resin: 16.7 g of resol-type phenolic resin (10 g as solid content)

Lubricant: 0.3 g of magnesium stearate

Leveling agent: Megaface F-477 0.3g

Solvent: terpineol 8g

Because the resistance value of the cured film was 2.5 Ω, the evaluation was “○”, the viscosity change rate before and after continuous printing was 105%, so the evaluation was “◎”, and the line width retention before and after intermittent printing was 85%, so the evaluation was “○” did

[Example 13]

It carried out similarly to Example 1 with the following formulation, and manufacture of the conductive composition and formation of the cured film were performed. Moreover, about each cured film, it carried out similarly to Example 1, and evaluated the resistance value, the viscosity change rate before and behind continuous printing, and the linewidth retention before and behind intermittent printing.

Component (a): PEG600 1.5g

Component (b): 1.5 g of lauric acid

Component (c) conductive particles: surface-coated copper particles (copper particles (1)) 87 g

Component (d) Binder resin: 10 g of resol type phenolic resin (6 g as solid content), 4 g of bisphenol F type epoxy resin

Dispersant: 1 g of oleoyl sarcosine

Solvent: terpineol 2g, isobornylcyclohexanol 6g

Because the resistance value of the cured film was 1.2 Ω, the evaluation was “○”, the rate of change of viscosity before and after continuous printing was 105%, so the evaluation was “◎”, and because the linewidth retention before and after intermittent printing was 95%, the evaluation was judged as “◎” did

Claims (1)

(a) 0.1 to 5 mass % of polyethylene glycol having an average molecular weight of 200 to 2,000;
(b) 0.1 to 5 mass % of an aliphatic monocarboxylic acid having 8 to 18 carbon atoms;
(c) 60-95 mass % of electroconductive particle, and
(d) 1-30 mass % of binder resin
Containing conductive composition.