Conductive paint

Abstract

Providing a conductive paint that can maintain the necessary coating film performance and obtain a coating film with good smoothness. 【Solution means】It contains a hydroxyl group-containing resin (A) that does not contain an epoxy group, a blocked carboxylic acid (B) having a latent carboxyl group, a conductive powder (C), and a curing agent (D) having a group that reacts with the hydroxyl group of the hydroxyl group-containing resin (A). The blocked carboxylic acid (B) is represented by any of the following formulas (1) to (4) and is contained in an amount of 0.05% by mass or more and 4.1% by mass or less in 100% by mass obtained by subtracting the volatile matter from the entire conductive paint. A conductive paint. TIFF0007705077000022.tif60170

Description

Technical Field

[0001] The present invention relates to a conductive paint.

Background Art

[0002] A conductive paint containing a resin and conductive powder can easily impart conductivity simply by applying it to an object to be coated and curing it, and since the process is simple and can be produced at low cost, it is widely used in the field of electronic devices. For example, Patent Document 1 discloses a conductive adhesive containing an epoxy resin, a phenolic resin, a reactive diluent, an imidazole compound, silver powder and / or silver-coated metal powder, and further containing a latent glutaric acid generating compound in the range of 0.05 to 5% by mass. Patent Document 2 discloses a conductive paste containing a metal powder (A), a resin (B) having an epoxy group or an oxetane group, and a latent carboxyl group generating compound (C).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the miniaturization and thinning of electronic devices, the miniaturization of electronic components has further advanced. Along with the miniaturization of electronic components, the performance required for conductive paints has also been enhanced. In order to achieve the miniaturization and thinning of electronic components, one of the performances required for conductive paints is the smoothness of the coating film. However, the coating films formed using conventional conductive paints as disclosed in Patent Documents 1 and 2 had good conductive performance, but had unevenness and insufficient smoothness.

[0005] Therefore, in order to improve the smoothness of the coating film obtained by the conductive paint, the inventors increased the ratio of the solvent in the conductive paint. As a result, it was found that although the smoothness improved when the ratio of the solvent was increased, sagging was likely to occur. Also, when the particle diameter of the conductive powder contained in the conductive paint was reduced, the smoothness of the coating film improved, but the resistivity increased. In view of the above circumstances, an object of the present invention is to provide a conductive paint capable of obtaining a coating film with good smoothness while maintaining the required coating film performance.

Means for Solving the Problems

[0006] In order to solve the above problems, the present invention employs the following configuration. [1] A hydroxyl group-containing resin (A) that does not contain an epoxy group, A blocked carboxylic acid (B) having a latent carboxyl group, Conductive powder (C), A curing agent (D) having a group that reacts with the hydroxyl group of the hydroxyl group-containing resin (A), and a conductive material containing the blocked carboxylic acid (B) is one or more selected from a compound having a structural unit represented by the following formula (1) and a compound represented by any one of the following formulas (2) to (4), the blocked carboxylic acid (B) is contained in an amount of 0.05% by mass or more and 4.1% by mass or less in 100% by mass obtained by subtracting the volatile content from the entire conductive paint.

Chemical Formula

Chemical Formula

[0007] [2] The conductive paint according to [1], wherein the hydroxyl group-containing resin (A) is at least one selected from polyester polyol, polycarbonate polyol, acrylic polyol, polyether polyol, polycaprolactone polyol, polyolefin polyol, polyurethane polyol, phenol resin, and xylene resin.

[0008] [3] The conductive paint according to [1] or [2], wherein the curing agent (D) is an isocyanate-based curing agent. [Advantages of the Invention]

[0009] According to the conductive paint of the present invention, a coating film with good smoothness can be obtained while maintaining the required coating film performance.

Embodiments for Carrying Out the Invention

[0010] The definitions of the following terms in this specification and the claims are as follows. "Vinyl (thio) ether" is a general term for vinyl ether and vinyl thioether. "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value.

[0011] The conductive paint of this embodiment includes a hydroxyl group-containing resin (A) that does not contain an epoxy group, a blocked carboxylic acid (B) having a latent carboxyl group, a conductive powder (C), and a curing agent (D). Further, it is preferably further included a solvent (E).

[0012] <Hydroxyl Group-Containing Resin (A)> The hydroxyl group-containing resin (A) is a resin having a hydroxyl group. However, those containing an epoxy group are excluded. Examples of the hydroxyl group-containing resin (A) include polyester polyol, polycarbonate polyol, acrylic polyol, polyether polyol, polycaprolactone polyol, polyolefin polyol, polyurethane polyol, phenol resin, and xylene resin. Among them, polyester polyol, polycarbonate polyol, and xylene resin are preferred because a coating film with good smoothness can be obtained.

[0013] Examples of the xylene resin include a multimer composition in which m-xylene is crosslinked with a methylene bond or an ether bond and a part of the terminal is an OH group, an alkylphenol-modified xylene resin obtained by modifying the multimer composition with an alkylphenol resin, a novolak-type xylene resin obtained by modifying the multimer composition with a phenol resin, a resol-type xylene resin obtained by modifying the multimer composition with a phenol resin, a xylene resin obtained by modifying the multimer composition with a polyol, and a xylene resin obtained by modifying the multimer composition with ethylene oxide.

[0014] As the xylene resin, commercially available products can be appropriately used. For example, the Nicanol series of Fudo Co., Ltd. (such as GHP-150, NP-100, P-100, etc.) can be mentioned. Among the xylene resins, a novolak-type xylene resin obtained by modifying the multimer composition with a phenol resin, a resol-type xylene resin obtained by modifying the multimer composition with a phenol resin, and a xylene resin obtained by modifying the multimer composition with a polyol are preferable because the chemical resistance of the coating film is improved.

[0015] The hydroxyl group-containing resin (A) may be used alone or in combination of two or more. When used in combination, a combination of a polyester polyol and a polycarbonate polyol, or a combination of a polyester polyol and a xylene resin is preferable because a coating film with good smoothness can be obtained.

[0016] The preferable range of the number average molecular weight (Mn) of the hydroxyl group-containing resin (A) varies depending on the type and use of the resin, but is preferably 500 to 50,000. When the number average molecular weight (Mn) of the hydroxyl group-containing resin (A) is equal to or higher than the preferable lower limit value, the mechanical strength of the cured coating film is excellent. When it is equal to or lower than the preferable upper limit value, the workability (printing characteristics) of the coating is improved. The number average molecular weight (Mn) of the hydroxyl group-containing resin (A) is the polystyrene-equivalent molecular weight measured using gel permeation chromatography (GPC) with tetrahydrofuran as the eluent and creating a calibration curve using a polystyrene polymer with a known molecular weight.

[0017] When using a polyester polyol as the hydroxyl group-containing resin (A), the number average molecular weight (Mn) of the polyester polyol in the hydroxyl group-containing resin (A) is preferably from 1,000 to 50,000, more preferably from 1,000 to 10,000. When using a polycarbonate diol as the hydroxyl group-containing resin (A), the number average molecular weight (Mn) of the polycarbonate diol in the hydroxyl group-containing resin (A) is preferably from 500 to 3,000. When using a xylene resin as the hydroxyl group-containing resin (A), the number average molecular weight (Mn) of the xylene resin in the hydroxyl group-containing resin (A) is preferably from 500 to 50,000.

[0018] The hydroxyl value of the hydroxyl group-containing resin (A) varies depending on the type and use of the resin, but is preferably from 1 to 500 mgKOH / g, more preferably from 1 to 300 mgKOH / g. When using a polyester polyol as the hydroxyl group-containing resin (A), the hydroxyl value of the polyester polyol in the hydroxyl group-containing resin (A) is preferably from 1 to 500 mgKOH / g, more preferably from 1 to 300 mgKOH / g.

[0019] When using a polycarbonate diol as the hydroxyl group-containing resin (A), the hydroxyl value of the polycarbonate diol in the hydroxyl group-containing resin (A) is preferably from 20 to 500 mgKOH / g. When using a xylene resin as the hydroxyl group-containing resin (A), the hydroxyl value of the polycarbonate diol in the hydroxyl group-containing resin (A) is preferably from 1 to 500 mgKOH / g, more preferably from 1 to 300 mgKOH / g.

[0020] <Blocked carboxylic acid (B)> The blocked carboxylic acid (B) has a latent carboxyl group, that is, a carboxyl group blocked by a protecting group. The blocked carboxylic acid (B) is obtained by an addition reaction of a carboxylic acid with a vinyl ether or the like serving as a protecting group. The blocked carboxylic acid (B) dissociates the protecting group by heating to generate a carboxylic acid.

[0021] The thermal decomposition start temperature at which the protecting group dissociates from the blocked carboxylic acid (B) is preferably 170 °C or lower, more preferably 80 to 150 °C. When the thermal decomposition start temperature is at or above the preferable lower limit value, the storage stability is enhanced. When it is at or below the preferable upper limit value, the protecting group can be promptly removed during the use of the conductive paint, and the activity of the carboxylic acid is likely to be expressed. Here, the thermal decomposition start temperature refers to the temperature at which the mass of the sample decreases by 1% when measuring the mass change while heating the sample at 10 °C / min.

[0022] The amount of the unblocked carboxyl groups of the blocked carboxylic acid (B) can be evaluated by the acid value. The acid value of the blocked carboxylic acid (B) is preferably 50 mgKOH / g or less, more preferably 35 mgKOH / g or less, still more preferably 25 mgKOH / g or less, and particularly preferably 10 mgKOH / g or less.

[0023] The reaction is preferably carried out such that all of the carboxyl groups of the carboxylic acid used in the production of the blocked carboxylic acid (B) are blocked, that is, the acid value of the blocked carboxylic acid (B) is as close as possible to 0 mgKOH / g. However, as long as it is within the above range, the storage stability of the conductive paint will be good.

[0024] The blocked carboxylic acid (B) is one or more selected from the following blocked carboxylic acids (B1) to (B4). The blocked carboxylic acid (B) may be used alone or in combination of two or more. In addition, each of the following formulas showing the blocked carboxylic acids (B1) to (B4) is represented in a form where all carboxyl groups are blocked. However, as long as the acid value is within an appropriate range, some unblocked carboxyl groups may remain.

[0025] [Blocked Carboxylic Acid (B1)] The blocked carboxylic acid (B1) is a compound having a repeating structural unit represented by the following formula (1). Both ends of the blocked carboxylic acid (B1) are a hydrogen atom or a group selected from a carboxy group and a vinyl group.

[0026]

Chemical formula

[0027] R in formula (1) 1 is a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, and R 2 is a divalent saturated hydrocarbon group which may contain an etheric oxygen and has 1 to 15 carbon atoms. R 2 may be either linear or branched. It may also have a cyclic structure.

[0028] R 1 being a single bond or a divalent saturated hydrocarbon group having 15 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms improves the smoothness of the coating film. R 1 is preferably a single bond or a divalent saturated hydrocarbon group having 8 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, more preferably a single bond or a divalent saturated hydrocarbon group having 6 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, and even more preferably a single bond or a divalent saturated hydrocarbon group having 4 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 4 or fewer carbon atoms.

[0029] R 2 having 15 or fewer carbon atoms allows the block to be easily removed promptly by heating and results in good reactivity during production. R 2 is particularly preferably a group represented by any one of the following formulas (5) to (8).

[0030]

Chemical formula

[0031]

Chem.

[0032]

Chem.

[0033]

Chem.

[0034] The weight average molecular weight (Mw) of the blocked carboxylic acid (B1) is preferably from 1,000 to 20,000, more preferably from 3,000 to 15,000. If the weight average molecular weight (Mw) of the blocked carboxylic acid (B1) is at least the above lower limit value, the storage stability is improved. If it is at most the above upper limit value, the smoothness of the coating film is improved.

[0035] The weight average molecular weight (Mw) of the blocked carboxylic acid (B) is the polystyrene equivalent molecular weight measured by creating a calibration curve using a gel permeation chromatography (GPC) with tetrahydrofuran as the eluent and a polystyrene polymer with a known molecular weight.

[0036] The blocked carboxylic acid (B1) can be obtained by subjecting a divalent saturated aliphatic carboxylic acid to an addition reaction with a vinyl (thio) ether having two vinyl ether groups. Specific examples of the divalent saturated aliphatic carboxylic acid and the vinyl (thio) ether having two vinyl ether groups will be described later.

[0037] [Blocked Carboxylic Acid (B2)] The blocked carboxylic acid (B2) is a compound represented by the following formula (2).

[0038]

Chem.

[0039] R in formula (2) 3 and R 5 are a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 16 carbon atoms, and R 4 is a divalent saturated hydrocarbon group which may contain an etheric oxygen and has 1 to 15 carbon atoms. R 3 and R 5 may be the same as or different from each other. R 4 may be either linear or branched. It may also have a cyclic structure.

[0040] R 3 and R 5 being a hydrogen atom or a monovalent saturated hydrocarbon group having 16 or less carbon atoms improves the smoothness of the coating film. R 3 and R 5 are preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 8 or less carbon atoms, more preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 6 or less carbon atoms, and even more preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 4 or less carbon atoms. R 4 having 15 or less carbon atoms allows the block to be easily removed promptly by heating and results in good reactivity during production. R 4 is particularly preferably a group represented by any one of the above formulas (5) to (8).

[0041] The blocked carboxylic acid (B2) is obtained by subjecting a monovalent saturated aliphatic carboxylic acid to an addition reaction with a vinyl (thio) ether having two vinyl ether groups. Specific examples of the monovalent saturated aliphatic carboxylic acid and the vinyl (thio) ether having two vinyl ether groups will be described later.

[0042] [Blocked carboxylic acid (B3)] The blocked carboxylic acid (B3) is a compound represented by the following formula (3).

[0043] [Chemical formula]

[0044] R in formula (3) 6 is a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 16 carbon atoms, and R 7 is a monovalent saturated hydrocarbon group which may contain an etheric oxygen atom having 1 to 18 carbon atoms. R 7 may be either linear or branched. It may also have a cyclic structure.

[0045] R 6 being a hydrogen atom or a monovalent saturated hydrocarbon group having 16 or fewer carbon atoms improves the smoothness of the coating film. R 6 is preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 8 or fewer carbon atoms, more preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 6 or fewer carbon atoms, and even more preferably a hydrogen atom or a monovalent saturated hydrocarbon group having 4 or fewer carbon atoms.

[0046] R 7 When the number of carbon atoms of R is 18 or less, the block is easily removed promptly by heating, and the reactivity during production becomes good. The number of carbon atoms of R 7 is preferably 1 to 8, more preferably 1 to 6, and particularly preferably 1 to 4. R 7 is most preferably a propyl group (-C3H7), a butyl group (-C4H9), or an octyl group (-C8H 17 ).

[0047] The blocked carboxylic acid (B3) is obtained by subjecting a monovalent saturated aliphatic carboxylic acid to an addition reaction with a vinyl (thio) ether having one vinyl ether group. Specific examples of the monovalent saturated aliphatic carboxylic acid and the vinyl (thio) ether having one vinyl ether group will be described later.

[0048] [Blocked carboxylic acid (B4)] The blocked carboxylic acid (B4) is a compound represented by the following formula (4).

[0049]

Chemical formula

[0050] R in formula (4) 8 and R 10 are monovalent saturated hydrocarbon groups which may contain an etheric oxygen atom and have 1 to 18 carbon atoms, and R 9 is a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms. R 8 and R 10 may be the same as or different from each other. R 8 and R 10 may be either linear or branched. They may also have a cyclic structure.

[0051] R 9 being a single bond or a divalent saturated hydrocarbon group having 15 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms improves the smoothness of the coating film. R 9 is preferably a hydrogen atom or a divalent saturated hydrocarbon group having 8 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, more preferably a hydrogen atom or a divalent saturated hydrocarbon group having 6 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, and even more preferably a hydrogen atom or a divalent saturated hydrocarbon group having 4 or fewer carbon atoms, or a divalent unsaturated hydrocarbon group having 4 or fewer carbon atoms.

[0052] R 8 and R 10 having 18 or fewer carbon atoms enables the block to be easily removed promptly by heating and results in good reactivity during production. The carbon number of R 8 and R 10 is preferably 1 to 8, more preferably 1 to 6, and particularly preferably 1 to 4. R 8 and R 10is most preferably a propyl group (-C3H7), butyl group (-C4H9), or octyl group (-C8H 17 )

[0053] The blocked carboxylic acid (B4) is obtained by subjecting a divalent saturated aliphatic carboxylic acid to an addition reaction with a vinyl (thio) ether having one vinyl ether group. Specific examples of the divalent saturated aliphatic carboxylic acid and the vinyl (thio) ether having one vinyl ether group will be described later.

[0054] [Carboxylic acid] Examples of the carboxylic acid serving as a raw material for the blocked carboxylic acid (B) include monovalent or divalent saturated aliphatic carboxylic acids, or divalent unsaturated carboxylic acids.

[0055] Examples of the monovalent saturated aliphatic carboxylic acid include formic acid, acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, and the like.

[0056] Examples of the divalent saturated aliphatic carboxylic acid include ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, 2,4 - diethylpentanedioic acid, and the like. Examples of the divalent unsaturated carboxylic acid include maleic acid.

[0057] Among these, carboxylic acids with relatively few carbon atoms and short molecular chains are highly reactive, and it is easy to produce the blocked carboxylic acid (B). Also, due to the good smoothness of the coating film, formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, and maleic acid are particularly preferred.

[0058] [Vinyl (thio) ether] Examples of the vinyl (thio) ether that serves as a raw material for the blocked carboxylic acid (B) include aliphatic vinyl ethers, alicyclic vinyl ethers, aliphatic vinyl thioethers, alicyclic vinyl thioethers, cyclic vinyl ethers, and cyclic vinyl thioethers.

[0059] Examples of the aliphatic vinyl ether having one vinyl ether group include monovinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-pentyl vinyl ether, n-pentyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, nonyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, tetradecyl vinyl ether, hexadecyl vinyl ether, heptadecyl vinyl ether, octadecyl vinyl ether, 2-ethylhexyl vinyl ether, hydroxyethyl vinyl ether, and hydroxybutyl vinyl ether.

[0060] Examples of aliphatic vinyl ethers having two vinyl ether groups include divinyl ether compounds such as (2-vinyloxyethyl) vinyl ether, 1,3-propanediol divinyl ether, 1,4-butanediol divinyl ether, 1,3-butanediol divinyl ether, 1,2-butanediol divinyl ether, 2,3-butanediol divinyl ether, 1,5-pentanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, (2-vinyloxyethyl) vinyl ether, diethylene glycol divinyl ether, dipropylene glycol divinyl ether, triethylene glycol divinyl ether, trimethylene glycol divinyl ether, tripropylene glycol divinyl ether, and tetrapropylene glycol divinyl ether.

[0061] Examples of alicyclic vinyl ethers having one vinyl ether group include monovinyl ether compounds such as cyclohexyl vinyl ether and cyclohexanedimethanol monovinyl ether. Examples of alicyclic vinyl ethers having two vinyl ether groups include divinyl ether compounds such as 1,4-cyclohexanedimethanol divinyl ether, 4,4-bis(vinyl oxymethyl) cyclohexene, 1,4-bis(ethenyloxy) benzene, bisphenol A divinyl ether, and bisphenol F divinyl ether.

[0062] Examples of aliphatic vinyl thioethers include thio compounds in which the etheric oxygen of the compounds exemplified as the aliphatic vinyl ethers is replaced with sulfur. Examples of alicyclic vinyl thioethers include thio compounds in which the etheric oxygen of the compounds exemplified as the alicyclic vinyl ethers is replaced with sulfur.

[0063] Examples of the cyclic vinyl ether include 2,3 - dihydrofuran, 3,4 - dihydrofuran, 2,3 - dihydro - 2H - pyran, 3,4 - dihydro - 2H - pyran, 3,4 - dihydro - 2 - methoxy - 2H - pyran, 3,4 - dihydro - 4,4 - dimethyl - 2H - pyran - 2 - one, 3,4 - dihydro - 2 - ethoxy - 2H - pyran, sodium 3,4 - dihydro - 2H - pyran - 2 - carboxylate, etc. Examples of the cyclic vinyl thioether include thio compounds in which the ether oxygen of the compounds exemplified as the cyclic vinyl ether is replaced with sulfur.

[0064] Among these, from the viewpoints of availability of raw materials and easy removal of the block promptly by heating, n - propyl vinyl ether, n - butyl vinyl ether, 2 - ethylhexyl vinyl ether, tetraethylene glycol divinyl ether, 1,4 - butanediol divinyl ether, 1,3 - butanediol divinyl ether, 1,2 - butanediol divinyl ether, 2,3 - butanediol divinyl ether, 1,4 - cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether are preferred.

[0065] [Production of Blocked Carboxylic Acid (B)] The reaction ratio of the carboxylic acid to the vinyl (thio) ether is usually 1.0:1.0 to 5.0, preferably 1.0:1.0 to 4.0, particularly preferably 1.0:1.0 to 3.0 in terms of equivalent ratio. The reaction temperature of the carboxylic acid and the vinyl (thio) ether is preferably 30 to 150°C, more preferably 30 to 100°C. The reaction time is preferably 10 minutes to 6 hours, more preferably 20 minutes to 5 hours. The end point of the reaction is judged, for example, by the fact that the acid value of the reaction system has decreased to an appropriate value.

[0066] <Conductive Powder (C)> The conductive powder (C) imparts conductivity to the coating film. The conductive powder (C) is not particularly limited as long as it can be used in conductive paints. Examples include metals such as gold, silver, copper, platinum, and nickel; and graphite. Among these, silver is preferred from the viewpoints of excellent conductivity and resistance to oxidation.

[0067] The conductive powder (C) may be composed of two or more elements. For example, alloys of the metals mentioned above can be used. Also, metals, alloys, or resins coated with the metals mentioned above may be used. Among these, from the viewpoints of excellent conductivity and resistance to oxidation, those obtained by coating metals, alloys, or resins other than silver with silver are preferred.

[0068] Since the workability (printing characteristics) is improved, the conductive powder (C) more preferably contains a conductive powder surface-treated with a fatty acid, and more preferably consists of a conductive powder surface-treated with a fatty acid. Examples of the fatty acid used for surface-treating the conductive powder (C) include oleic acid, stearic acid, and lauric acid. Examples of the method for surface-treating the conductive powder (C) with a fatty acid include a method in which a fatty acid diluted in a solvent and the conductive powder are mixed with a ball mill or the like and then dried. The conductive powder (C) may be used alone or in combination of two or more.

[0069] The average particle diameter of the conductive powder (C) is preferably 0.1 to 15 μm, more preferably 0.2 to 10 μm, still more preferably 0.3 to 7.5 μm, and particularly preferably 0.5 to 5.0 μm. When the average particle diameter of the conductive powder (C) is at or above the preferred lower limit value, the conductivity of the coating film is improved. When it is at or below the preferred upper limit value, the smoothness of the coating film is improved. The average particle diameter of the conductive powder (C) is the cumulative 50% diameter in the volume-based particle size distribution measured by a laser diffraction / scattering particle size distribution analyzer.

[0070] The shape of the conductive powder (C) is not particularly limited, and various shapes such as flake-like (which can also be referred to as scaly, flat, plate-like, or flaky), spherical, cubic, needle-like, granular (irregular spherical), beaded, a shape with protrusions on the surface like a sugar cube, amorphous, and aggregates can be used. In the present invention, "amorphous" means a mixture of two or more various shapes such as spherical, cubic, needle-like, granular, beaded, or a shape with protrusions on the surface like a sugar cube, and the shape cannot be limited.

[0071] In the present invention, "aggregate" means an aggregate in which the primary particles include one or more shapes selected from spherical, cubic, needle-like, granular, beaded, or a shape with protrusions on the surface like a sugar cube. The amorphous preferably includes granular. The aggregate preferably has primary particles including granular, and more preferably consists only of granular primary particles.

[0072] Among these, the conductive powder (C) is preferably flake-like, granular, amorphous, aggregate, a combination of flake-like and granular, a combination of flake-like and amorphous, or a combination of flake-like and aggregate. When the conductive powder (C) is flake-like, a combination of flake-like and granular, a combination of flake-like and amorphous, or a combination of flake-like and aggregate, the specific resistance of the conductive paint film becomes better. When the conductive powder (C) is granular, amorphous, or aggregate, the flexibility and printing characteristics of the conductive paint film become better.

[0073] <Hardener> The conductive paint of the present embodiment further includes a hardener (D). The hardener has a group that reacts with the hydroxyl group of the hydroxyl group-containing resin (A).

[0074] Examples of the curing agent include amine-based curing agents, epoxy-based curing agents, isocyanate-based curing agents, melamine-based curing agents, aziridine-based curing agents, hydrazine-based curing agents, aldehyde-based curing agents, oxazoline-based curing agents, metal alkoxide-based curing agents, metal chelate-based curing agents, metal salt-based curing agents, ammonium salt-based curing agents, etc., and they can be appropriately selected according to the required paint performance and coating film performance. Among these, isocyanate-based curing agents are preferred because block-type curing agents are easily available, so there is a selectivity between block-type and non-block-type, and also because of their excellent reactivity with hydroxyl groups. The curing agent may be used alone or in combination of two or more.

[0075] Examples of the isocyanate-based curing agent include triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, etc.; diisocyanates such as methylene diisocyanate, isopropylidene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate; biuret-type, adduct-type, isocyanurate-type, etc. of those mentioned above; block-type of polyisocyanates of those mentioned above, etc. The isocyanate-based crosslinking agent may be used alone or in combination of two or more.

[0076] When using an isocyanate-based curing agent as the curing agent, the isocyanate index (molar number of NCO of the curing agent / molar number of OH of the hydroxyl group-containing resin (A) × 100) is preferably 0.8 to 15.0, and more preferably 1.0 to 10.0. When the isocyanate index is above the preferred lower limit, the curability is improved. When it is below the preferred upper limit, the conductivity is improved.

[0077] <Solvent> If the conductive paint contains a solvent, its viscosity can be easily adjusted. As the solvent, those capable of dissolving the hydroxyl group-containing resin (A) are preferred. Examples of the solvent include alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, t-butanol, allyl alcohol, benzyl alcohol, terpineol, n-dodecanol, ethylene glycol, 3-methoxy-3-methyl-1-butanol, diethylene glycol, and propylene glycol.

[0078] In addition, examples of the solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, γ-butyrolactone, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. In addition, examples of the solvent include ether solvents such as dimethyl ether, diethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0079] In addition, examples of the solvent include ketone solvents such as diethyl ketone, methyl propyl ketone, methyl butyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl amyl ketone, diisopropyl ketone, methyl ethyl ketone, acetone, diacetone alcohol, and isophorone.

[0080] In addition, examples of the solvent include aromatic hydrocarbon solvents such as toluene, xylene, diamylbenzene, triamylbenzene, benzene, ethylbenzene, propylbenzene, and isopropylbenzene. In addition, examples of the solvent include hydrocarbon solvents such as cyclohexane and n-hexane. In addition, examples of the solvent include amide solvents such as N,N-dimethylacetamide and N,N-dimethylformamide.

[0081] In addition, for example, glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol monomethyl ether, and diethylene glycol dibutyl ether can be mentioned.

[0082] In addition, for example, ether esters such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol diacetate, propylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate can be mentioned.

[0083] The solvent may be used alone or in combination of two or more. It is preferable that the solvent is formulated so that the proportion of the solid content obtained by subtracting the volatile content from the total amount of the conductive paint in the conductive paint is 60 to 95% by mass, and more preferably 70 to 90% by mass.

[0084] <Other Components> The conductive paint of this embodiment may contain other components as necessary. Examples of other components include components that can be used in conventionally known conductive paints, such as dispersants, surface modifiers, thixotropic agents, adhesion promoters, resin modifiers, catalysts, coupling agents, and non-conductive fillers.

[0085] <Ratio of Each Component> The total content of the hydroxyl group-containing resin (A) and the curing agent (D) in the conductive paint of the present embodiment is preferably 5 to 30% by mass, more preferably 5 to 25% by mass, in 100% by mass obtained by subtracting the volatile content from the total conductive paint. When the total content of the hydroxyl group-containing resin (A) and the curing agent (D) is at or above the preferable lower limit value, a uniform conductive paint can be obtained. When it is at or below the preferable upper limit value, the conductivity is improved.

[0086] The content of the blocked carboxylic acid (B) in the conductive paint is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, in 100% by mass obtained by subtracting the volatile content from the total conductive paint. The content of the blocked carboxylic acid (B) in the conductive paint is preferably 4.1% by mass or less, more preferably 2.5% by mass or less, in 100% by mass obtained by subtracting the volatile content from the total conductive paint. When the content of the blocked carboxylic acid (B) is within the above range, the smoothness of the coating film becomes good.

[0087] The content of the conductive powder (C) in the conductive paint is preferably 70% by mass or more, more preferably 75% by mass or more, in 100% by mass obtained by subtracting the volatile content from the total conductive paint. The content of the conductive powder (C) in the conductive paint is preferably 95% by mass or less, more preferably 92% by mass or less, in 100% by mass obtained by subtracting the volatile content from the total conductive paint. When the content of the conductive powder (C) is at or above the preferable lower limit value, the resistivity is more likely to decrease. When it is at or below the preferable upper limit value, it is easy to ensure the adhesive strength and avoid the cost from rising more than necessary.

[0088] <Manufacturing method> The conductive paint is obtained by mixing the above-mentioned hydroxyl group-containing resin (A), blocked carboxylic acid (B), conductive powder (C), and, if necessary, other components. For the mixing, a mixer such as a roll mill or a planetary mixer may be used, for example.

[0089] <Function and effect> Since the conductive paint of the above embodiment contains the hydroxyl group-containing resin (A), the blocked carboxylic acid (B), and the conductive powder (C) described above, it is possible to form a coating film having good smoothness without deteriorating the coatability and conductivity.

[0090] In examining the present invention, the inventors first comparatively examined various resins. As a result, it was found that when an epoxy resin is used for the conductive paint, the smoothness deteriorates, and when a hydroxyl group-containing resin (A) not containing an epoxy group is used, the smoothness improves. The mechanism by which the smoothness deteriorates when a resin having an epoxy group is used is unclear, but it is considered that the properties of the resin due to having an epoxy group and the properties resulting from the chemical bond between the resin before curing and the curing agent affect the smoothness when the conductive paint is applied.

[0091] The inventors also examined various types of carboxylic acids and vinyl ethers as raw materials for the blocked carboxylic acid (B), and as a result, discovered that the smoothness varies significantly depending on the type of carboxylic acid used. Specifically, it was found that when a carboxylic acid having 18 or more carbon atoms or a carboxylic acid having a bulky structure is used, the smoothness deteriorates, and when a carboxylic acid having a small number of carbon atoms and no bulky structure is used, good smoothness is achieved. Examples of the carboxylic acid having a bulky structure include carboxylic acids having a benzene ring, carboxylic acids that can only be represented three-dimensionally such as n-propyl vinyl ether-blocked dimethyladamantane dicarboxylic acid and norbornadiene.

[0092] Next, the inventors examined various conductive powders (C). Regarding silver, it was found that the influence on the smoothness due to the difference in the presence or absence of fatty acid treatment is small. And it was found that the presence or absence of the blocked carboxylic acid (B) has a greater influence on the smoothness than the difference in the conductive powder (C).

[0093] Based on these examination results, the following are considered as the reasons for the good smoothness of the conductive paint coating film of the present invention. First, when the conductive paint containing silver treated with a fatty acid such as stearic acid does not contain the blocked carboxylic acid (B), the factor causing poor smoothness of the conductive paint is that the silver is in a bulky state due to the fatty acid, which adversely affects the fluidity of the conductive paint film. As a result, it is considered that the smoothness deteriorates.

[0094] On the other hand, a conductive paint containing silver treated with a fatty acid such as stearic acid and containing the blocked carboxylic acid (B) is such that the carboxylic acid dissociated from the blocked carboxylic acid (B) binds to the surface of the silver and replaces the fatty acid such as stearic acid bound to the surface of the silver. As a result, the bulkiness of the silver decreases, the fluidity of the conductive paint film changes, and it is presumed that the smoothness is improved.

[0095] On the other hand, when the conductive paint containing silver that has not been treated with a fatty acid does not contain the blocked carboxylic acid (B), the factor causing poor smoothness of the conductive paint is that since the silver that has not been treated with a fatty acid is an inorganic substance, it is difficult to mix with the hydroxyl group-containing resin (A) that is an organic substance, and the poor compatibility between the silver and the hydroxyl group-containing resin (A) adversely affects the fluidity of the conductive paint film. As a result, it is considered that the smoothness deteriorates.

[0096] In contrast, a conductive paint containing silver that has not been treated with a fatty acid and containing the blocked carboxylic acid (B) is such that the carboxylic acid dissociated from the blocked carboxylic acid (B) binds to the surface of the silver, which makes it easier for the silver and the hydroxyl group-containing resin (A) to mix, and it is presumed that the smoothness is improved.

[0097] <Use> Examples of the use of the conductive paint of the present embodiment include use for circuits of electronic components. The coating film can be obtained, for example, by applying the conductive paint of the present embodiment on a substrate and drying it. The substrate is not particularly limited.

[0098] A printed wiring board can be obtained by forming a circuit with a coating film (conductive coating film) obtained using the conductive paint of the above embodiment on an insulating substrate. As the insulating substrate, conventionally known ones used as wiring boards can be used, such as substrates made of inorganic materials such as glass substrates, ceramic substrates, and silicon substrates; substrates made of organic materials, etc.

[0099] Examples of the organic material constituting the insulating substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate. Also, for example, silicones such as polydimethylsiloxane, polyphenylpolysiloxane, and polyfluorosiloxane can be mentioned.

[0100] Also, for example, urethanes such as thermoplastic polyurethane elastomers can be mentioned. Also, for example, polyolefins such as polyethylene and polypropylene can be mentioned. Also, for example, polyimides, polyphenylene sulfides, polyamides, polystyrenes, acrylics, polyvinyl alcohols, ethylene propylene dienes, epoxies, polycarbonates, etc. can be mentioned.

[0101] The thickness of the insulating substrate may be appropriately set according to the use of the printed wiring board, etc., but for example, 20 to 600 μm is preferable. The method for forming a circuit on the insulating substrate is not particularly limited, but for example, a method of applying the conductive paint of the above embodiment on the insulating substrate so as to obtain a desired circuit pattern and drying it to form a circuit composed of a coating film can be mentioned.

[0102] That is, as an embodiment of the method for manufacturing a printed wiring board, it has a pattern forming step of applying the conductive paint of the above embodiment on an insulating substrate to form a circuit pattern, and a drying step of drying the circuit pattern. Examples of the method for applying the conductive paint include, for example, gravure printing, offset printing, screen printing, etc. For forming a fine circuit, screen printing is preferred. Also, examples of the method for applying over a large area include roll coating, bar coating, spray coating, etc.

[0103] Examples of the drying and curing method after applying the conductive paint include, for example, hot air drying furnaces such as box furnaces and tunnel furnaces, infrared curing furnaces, ultraviolet curing furnaces, electron beam irradiation devices, etc. The drying temperature is preferably, for example, 70 to 160°C. The drying or curing time is preferably, for example, 2 to 60 minutes.

Examples

[0104] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0105] [Raw materials] The raw materials used in each example are as follows.

[0106] [Resin (A)] · Polyester resin 1: ADEKA Corporation, trade name "NS-2400", number average molecular weight 2,000, hydroxyl value 56 mgKOH / g. · Polyester resin 2: Nippon Synthetic Chemical Industry Co., Ltd., trade name "Polyester (registered trademark) SNT", number average molecular weight 10,000, hydroxyl value 8 mgKOH / g.

[0107] · Polyester resin 3: Toyobo Co., Ltd., trade name "Bylon (registered trademark) 300", number average molecular weight 23,000, hydroxyl value 5.0 mgKOH / g. · Polycarbonate resin: Asahi Kasei Corporation, trade name "T4691", number average molecular weight 1,000, hydroxyl value 119.4 mgKOH / g. · Xylene resin: Fudo Co., Ltd., trade name "HP-100", number average molecular weight 1200, hydroxyl value 140 mgKOH / g. · Phenolic resin: Meiwafosis Co., Ltd., trade name "MEH8005", a novolac-type phenolic resin that is liquid at room temperature, with a weight average molecular weight of 520.

[0108] [Resin (AX)] · Epoxy resin: Mitsubishi Chemical Corporation, trade name "jER®807", an epoxy resin that is liquid at room temperature, bisphenol F type.

[0109] [Carboxylic acid (b1)] · Methanoic acid: monovalent, molecular weight 46.03 g / mol. · Ethanedioic acid: divalent, molecular weight 90.03 g / mol. · Pentanedioic acid: divalent, molecular weight 132.12 g / mol. · Decanedioic acid: divalent, molecular weight 202.25 g / mol. [Carboxylic acid (b1x)] · Eicosanedioic acid: divalent, molecular weight 342.52 g / mol.

[0110] [Vinyl ether (b2)] · 1,4-Butanediol divinyl ether: divalent, molecular weight 142.20 g / mol.

[0111] [Conductive powder] · Silver powder 1: manufactured by Ames Advanced Materials Corporation, trade name "Silver Powder SPS", average particle diameter 3 μm, granular, with fatty acid treatment. · Silver powder 2: manufactured by Ames Advanced Materials Corporation, trade name "Silver Powder K-1", average particle diameter 1.89 μm, granular, without fatty acid treatment.

[0112] [Hardener (D)] · Isocyanate 1: Asahi Kasei Corporation, trade name "17B-60P", biuret-type blocked HDI, solid content 60 mass%, effective NCO 9.5 mass%. [Solvent (E)] · Ethylene glycol monobutyl ether acetate.

[0113] [Others] · Imidazole compound: Shikoku Kasei Kogyo Co., Ltd., trade name "2PHZ", an imidazole-based epoxy curing accelerator. · Reactive diluent: Nippon Kayaku Co., Ltd., trade name "GOT", glycidyl orthotoluidine.

[0114] <Examples 1 - 15, Comparative Examples 1 - 7> [Production of Blocked Carboxylic Acid (B)] According to the formulations shown in Tables 1 - 5, (b1) and (b2) were mixed and reacted at 70 °C for 1 hour. The reaction was terminated when the acid value of the reaction system reached 10 mgKOH / g or less. For Comparative Examples 2 - 4, blocked carboxylic acid (B) was not produced. In addition, in Comparative Example 5, (b1x) was used instead of (b1).

[0115] [Production of Conductive Paint] According to the formulations shown in Tables 1 - 5, each material was mixed to obtain the conductive paint for each example. For Comparative Examples 2 - 4, instead of blocked carboxylic acid (B), one or both of the compounds corresponding to (b1) and (b2) were used as monomers.

[0116] [Performance Evaluation] [Preparation of Specimen (I)] For each example, each conductive paint was applied by silk screen printing onto a PET film (Lumirror S: manufactured by Toray Industries, Inc.) (width 15 mm, length 70 mm, thickness 100 μm) annealed at 155 °C for 1 hour to form a pattern with a width of 1 mm and a length of 50 mm. Thereafter, it was dried at 150 °C for 30 minutes to cure the coating film, and a specimen (I) with a conductive circuit having a dry film thickness of 8 - 11 μm was prepared.

[0117] [Evaluation of Smoothness] Specimen (I) was measured using a surface roughness measuring instrument (Surfcorder SE3500: manufactured by Kosaka Laboratory Ltd.). Five maximum values and five minimum values of the obtained waveform were arbitrarily selected, and the average value of each was determined. Further, the difference between the average value of the maximum values and the average value of the minimum values was determined, and this difference was used as an evaluation index for smoothness. The results are shown in Tables 1 to 3.

[0118] [Evaluation of Printing Characteristics] For Specimen (I), evaluation was carried out according to the following criteria. The results are shown in Tables 1 to 3. Evaluation Criteria: 〇: A uniform conductive paint film, a good circuit without sagging, defects, etc. △: At a level with no practical problems, unevenness, sagging, or defects in the conductive paint film are observed in a minute area. ×: Unevenness, sagging, or defects in the conductive paint film are observed at multiple locations.

[0119] [Preparation of Specimen (II)] Except that each conductive paint was applied by silk screen printing to form a pattern with a width of 20 mm and a length of 200 mm, in the same manner as Specimen (I), Specimen (II) in which a conductive circuit with a dry film thickness of 8 to 11 μm of each conductive paint film was formed was prepared.

[0120] [Evaluation of Specific Resistance] For Specimen (II), the resistance value (R), film thickness (A), electrode width (B), and electrode distance (C) were measured, and the specific resistance ρ was calculated by the following formula. The results are shown in Tables 1 to 5. The resistance value was measured using a digital multimeter (product name: R6581D) manufactured by ADVANTEST Corporation, and the film thickness was measured using a surface roughness meter (product name: SE3500) manufactured by Kosaka Laboratory Ltd. ρ = R × {(A × B) / C}

[0121] [Evaluation of Pencil Hardness] Specimen (II) was placed on a hard flat surface and evaluated according to JIS K 5600-5-4 (1999). The results are shown in Tables 1 to 5.

[0122] [Evaluation of Storage Stability] The storage stability of the conductive paint was evaluated based on the viscosity after the paint was allowed to stand and stored at 50°C for 7 days, and the evaluation was conducted according to the following criteria. The results are shown in Tables 1 to 5. Evaluation criteria: ○: Equivalent to the initial stage of production, or there is a slight viscosity change but no problem as a product. ×: There is a significant viscosity change compared to the initial stage of production, or it has gelled.

[0123]

Table 1

[0124]

Table 2

[0125]

Table 3

[0126]

Table 4

[0127]

Table 5

[0128] As shown in Tables 1 to 3, all the examples obtained results without problems in any evaluation item. However, for Example 3, since the molecular weight of the polyester polyol of resin (A) was relatively large, the printing properties were slightly inferior. For Example 9, since the number of carbon atoms of the carboxylic acid used as the raw material of the blocked carboxylic acid (B) was relatively large, the smoothness was slightly inferior. For Example 11, since the content of the blocked carboxylic acid (B) was relatively small, the smoothness was slightly inferior. For Example 12, since the silver powder used in the conductive powder (C) was not treated with fatty acid, the printing properties were slightly inferior.

[0129] On the other hand, as shown in Tables 4 and 5, Comparative Example 1 containing an epoxy resin had poor smoothness. Comparative Example 2 and Comparative Example 4 using a carboxylic acid without blocking had poor storage stability. Comparative Example 3 not using a carboxylic acid had poor smoothness. Comparative Example 5 in which the number of carbon atoms of the carboxylic acid serving as a raw material for the blocked carboxylic acid (B) was too large had poor smoothness. Comparative Example 6 in which the content of the blocked carboxylic acid (B) was too small had poor smoothness.

Claims

1. A hydroxyl group-containing resin (A) that does not contain an epoxy group, A blocked carboxylic acid (B) having a latent carboxyl group, Conductive powder (C), A curing agent (D) having a group that reacts with the hydroxyl group of the hydroxyl group-containing resin (A), A conductive paint containing The blocked carboxylic acid (B) is one or more selected from a compound having a structural unit represented by the following formula (1) and a compound represented by any one of the following formulas (2) to (4), A conductive paint containing 0.05% by mass or more and 4.1% by mass or less of the blocked carboxylic acid (B) in 100% by mass obtained by subtracting the volatile content from the entire conductive paint. 【Chemical 1】 (R in formula (1) １ is a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms, and R ２ is a divalent saturated hydrocarbon group which may contain an etheric oxygen and has 1 to 15 carbon atoms.) 【Chemical 2】 (R in formula (2) ３ and R ５ are a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 16 carbon atoms, and R ４ is a divalent saturated hydrocarbon group which may contain an etheric oxygen atom having 1 to 15 carbon atoms. R ３ and R ５ may be the same as or different from each other.) 【Chemical 3】 (In formula (3), R ６ is a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 16 carbon atoms, and R ７ is a monovalent saturated hydrocarbon group which may contain an etheric oxygen having 1 to 18 carbon atoms.) 【Chemical Formula 4】 (R in formula (4) ８ and R １０ are monovalent saturated hydrocarbon groups which may contain an etheric oxygen and have 1 to 18 carbon atoms, and R ９ is a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a divalent unsaturated hydrocarbon group having 2 to 5 carbon atoms. R ８ and R １０ may be the same as or different from each other.)

2. The conductive paint according to Claim 1, wherein the hydroxyl group-containing resin (A) is one or more selected from polyester polyol, polycarbonate polyol, acrylic polyol, polyether polyol, polycaprolactone polyol, polyolefin polyol, polyurethane polyol, phenol resin, and xylene resin.

3. The conductive paint according to Claim 1 or 2, wherein the curing agent (D) is an isocyanate-based curing agent.

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