Conductive pigment paste, coating material, and coating film

Abstract

The present invention addresses the problem of providing: a conductive pigment paste which exhibits excellent pigment dispersibility and excellent storage stability even in cases where the pigment concentration is high; a coating material; and a coating film which exhibits excellent finish properties and the like. The present invention provides, as a means for solving the problem, a conductive pigment paste which contains (A) a pigment dispersion resin, (B) a conductive pigment, (C) a solvent and (D) a fluororesin, wherein: the pigment dispersion resin (A) has at least one a polar functional group that is selected from the group consisting of an amide group, an imide group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, an amino group and a cyano group; the polar functional group concentration in the pigment dispersion resin (A) is from 10 mmol / g to 23 mmol / g; the conductive pigment (B) has an average primary particle diameter of 10 nm to 80 nm and a BET specific surface area of 250 m2 / g or less; the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) satisfy the relational expression |δA - δC| < 2.0; and the viscosity at a shear rate of 0.1 s-1 is less than 5,000 mPa·s.

Description

[Technical Field]

[0001] The present invention relates to a conductive pigment paste and coating material that exhibits excellent pigment dispersibility and storage stability even at high pigment concentrations, as well as a coating film that exhibits excellent finish properties. [Background technology]

[0002] Conventionally, paste-like pigment dispersions, in which pigments are dispersed in a mixture of pigment dispersion resin and solvent, have been widely used in fields such as paints, coatings, electromagnetic shielding, display panels, touchscreen panels, colored films, colored sheets, cosmetic materials, protective materials, magnet modifiers, printing inks, device components, electrodes for secondary batteries, electronic equipment components, printed circuit boards, solar cells, functional rubber components, and resin molded films. Furthermore, conductive pigments and conductive polymers are added to these materials to impart functions such as electrostatic coating properties, conductivity, electromagnetic shielding properties, antistatic properties, and battery performance. In these fields, there is an increasing demand for improved performance in areas such as pigment dispersibility, storage stability, coating properties, conductivity, finish, and solvent resistance. Therefore, pigment dispersion resins and pigment pastes are being developed that possess excellent pigment dispersion capabilities and excellent storage stability that prevents the re-aggregation of pigment particles in the formed pigment dispersion.

[0003] In designing pigment pastes, it is important to produce a highly concentrated and uniformly dispersed pigment paste using a small amount of pigment dispersion resin, in order to prevent the pigment dispersion resin from negatively affecting the conductivity of the final product itself, such as the coating film, and to reduce the amount of solvent and pigment dispersion resin used, as well as the energy used during drying. For example, Patent Document 1 discloses a conductive pigment paste containing carbon-coated metal particles, which use metal particles as a core material and have their surfaces coated with carbon, a binder resin, and a solvent. However, because it uses expensive conductive materials such as silver and copper, it could not be used for general-purpose materials. Furthermore, Patent Document 2 discloses a conductive sheet in which carbon nanotubes and carbon black are dispersed in a resin material, and which contains a carbon composite filler in a ratio of 10 to 50% by weight and the resin material in a ratio of 90 to 50% by weight. However, this paste sometimes lacked sufficient conductivity due to its low pigment concentration (high resin ratio). Furthermore, Patent Document 3 describes a conductive additive dispersion containing at least two different carbon materials and a solvent, wherein the first conductive additive has an average primary particle size of 20-50 nm and a BET specific surface area of ​​300-1,400 m². 2 The second conductive additive has an average dispersion particle size of 280-1,500 nm per g, and an average primary particle size of 20-70 nm and a BET specific surface area of ​​10-200 m². 2 A conductive additive dispersion is disclosed, having a density of 500-1,500 nm per g, an average dispersed particle size of 500-1,500 nm, and a mass ratio of 20-80:80-20 between the first and second conductive additives. However, this dispersion sometimes lacked sufficient dispersibility because it contained 20% or more by mass of carbon material with a large specific surface area. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-22598 [Patent Document 2] International Publication No. 2015 / 064708 [Patent Document 3] Japanese Patent Publication No. 2019-61916 [Overview of the project] [Problems that the invention aims to solve]

[0005] The problem that the present invention aims to solve is to provide a conductive pigment paste and coating material that exhibits excellent pigment dispersibility and storage stability even at high pigment concentrations, and furthermore, to provide a coating film that exhibits excellent finish properties. [Means for solving the problem]

[0006] As a result of intensive studies to solve the above problems, the inventors have found that the above problems can be solved by a conductive pigment paste containing a specific pigment dispersion resin (A), a conductive pigment (B), a solvent (C), and a fluororesin (D), and have completed the present invention. That is, the present invention provides the following conductive pigment paste, coating material, and coating film. Item 1: A conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), a solvent (C), and a fluororesin (D), where the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, an amino group, and a cyano group, and the polar functional group concentration of the pigment dispersion resin (A) is 10 to 23 mmol / g, the conductive pigment (B) has an average primary particle diameter of 10 to 80 nm and a BET specific surface area of 250 m 2 / g or less, the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) satisfy the relationship |δA - δC| < 2.0, and the viscosity at a shear rate of 0.1 s -1 is less than 5,000 mPa·s, the conductive pigment paste. Item 2: The conductive pigment paste according to Item 1, wherein the solid content of the pigment dispersion resin (A) is 0.1 to 20% by mass based on the total solid content of the conductive pigment paste. Item 3: The conductive pigment paste according to Item 1 or 2, wherein the content of the conductive pigment (B) is 5 to 99.9% by mass based on the total solid content of the conductive pigment paste. Item 4: The conductive pigment paste according to any one of Items 1 to 3, wherein the solubility parameter δA of the pigment dispersion resin (A) is 9.3 or more, and the solubility parameter δC of the solvent (C) is 10.4 to15.0. Item 5: The conductive pigment paste is diluted with a solvent, and the frequency distribution curve obtained by measuring the volume-based particle size distribution by the laser diffraction scattering method has at least two peaks. At least one peak top of the peaks is in the range of particle diameter of 150 to 550 nm, and at least one is in the range of particle diameter of 600 to 3,000 nm. The peak area ratio in the above particle diameter range (sum of peak areas in the range of particle diameter of 150 to 550 nm / sum of peak areas in the range of particle diameter of 600 to 3,000 nm) is 0.2 to 3. The conductive pigment paste according to any one of Items 1 to 4. Item 6: The conductive pigment paste is diluted with a solvent, and the average particle diameter (D50) obtained by measuring the volume-based particle size distribution by the laser diffraction scattering method is 860 to 1,400 nm. The conductive pigment paste according to any one of Items 1 to 5. Item 7: The shear rate of the conductive pigment paste is 0.1 s -1 The viscosity X and the shear rate of 1,000 s -1 The viscosity Y have a relationship of 500 mPa·s < X < 5,000 mPa·s and X / Y > 1.0. The conductive pigment paste according to any one of Items 1 to 6. Item 8: The conductive pigment (B) is at least one conductive carbon selected from the group consisting of acetylene black, ketjen black, furnace black, thermal black, graphene, and graphite. The conductive pigment paste according to any one of Items 1 to 7. Item 9: Further containing a high-polarity low-molecular-weight component (E). The conductive pigment paste according to any one of Items 1 to 8. Item 10: The high-polarity low-molecular-weight component (E) contains at least one amine compound (E1). The conductive pigment paste according to any one of Items 1 to 9. Item 11: The fluororesin (D) is a resin having a weight average molecular weight of 100,000 or more and a solubility parameter δD of less than 9.3. The conductive pigment paste according to any one of Items 1 to 10. Item 12: A conductive pigment paste comprising a conductive pigment paste described in any one of items 1 to 11 and carbon nanotubes (F), wherein the solid content ratio of conductive pigment (B) to carbon nanotubes in the conductive pigment paste is 1 / 99 to 99 / 1. Item 13: A conductive pigment paste containing a pigment dispersion resin (A), acetylene black (B-2), carbon nanotubes (F), a solvent (C), and a fluororesin (D), The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups, and the concentration of the polar functional group of the pigment dispersion resin (A) is 10 to 23 mmol / g. Acetylene black (B-2) has an average primary particle size of 10-80 nm and a BET specific surface area of ​​250 m². 2 It is less than / g The solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) are related by |δA-δC|<2.0. Shear rate 0.1s -1 The viscosity is less than 5,000 mPa·s. Conductive pigment paste. Item 14: A method for dispersing a conductive pigment paste, wherein the conductive pigment paste is dispersed substantially without the use of a mediator, in the production of a conductive pigment paste as described in any one of items 1 to 11. Item 15: A coating material comprising a conductive pigment paste as described in any one of items 1 to 13 and metal-containing particles (G) having at least one metallic element. Item 16: A coating material comprising a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), a solvent (C), a fluororesin (D), and a highly polar, low molecular weight component (E), and metal-containing particles (G) having at least one metal element, The pigment-dispersing resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, an amino group, and a cyano group, and the polar functional group concentration of the pigment-dispersing resin (A) is 10 to 23 mmol / g. The conductive pigment (B) has an average primary particle diameter of 10 to 80 nm and a BET specific surface area of 250 m 2 / g or less. The solubility parameter δA of the pigment-dispersing resin (A) and the solubility parameter δC of the solvent (C) satisfy the relationship |δA - δC| < 2.0. The viscosity at a shear rate of 0.1 s -1 is less than 5,000 mPa·s. The high-polarity low-molecular-weight component (E) is contained in an amount of 3% by mass or more based on 100% by mass of the solid content of the conductive pigment (B). Coating material. Item 17: A method for producing a coating material, comprising adding metal-containing particles (G) having at least one metal element to the conductive pigment paste according to any one of Items 1 to 13. Item 18: A coated film obtained by coating the coating material according to Item 15 or 16. Item 19: A coating material obtained by coating both sides of a plate-shaped substrate with the coating material according to Item 15 or 16.

Advantages of the Invention

[0007] The conductive pigment paste and the coating material of the present invention are excellent in pigment dispersibility and storage stability even at a high pigment concentration, and can sufficiently reduce the viscosity of the paste with a relatively small blending amount. Further, the conductive coated film is excellent in finish and the like.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention will be described in detail. It should be understood that the present invention is not limited to the following embodiments, and includes various modified examples implemented within the scope not changing the gist of the present invention.

[0009] The conductive pigment paste of the present invention includes a conductive pigment paste according to a first embodiment and a conductive pigment paste according to a second embodiment. The "coating material" of the present invention is a liquid composition containing a conductive pigment paste. The "coated film" of the present invention is a solid composition obtained by applying and drying the aforementioned coating material. The "coated material" of the present invention is obtained by coating the aforementioned coating material onto both sides of a plate-shaped substrate. Here, the solubility parameter, also commonly called the SP value (solubility parameter), is a measure that indicates the degree of hydrophilicity or hydrophobicity (polarity) of a solvent or resin. It is also an important measure for determining the solubility and compatibility between a solvent and a resin, and between resins. Generally, when the solubility parameter values ​​are close (the absolute value of the difference in solubility parameters is small), the solubility and compatibility are good. In this invention, first, a conductive pigment paste having a conductive pigment (B) in an appropriate dispersion state is prepared. Furthermore, in order to obtain a coating film that satisfies various performance requirements, components such as metal-containing particles are added to the conductive pigment paste to produce a coating material.

[0010] [Conductive pigment paste according to the first embodiment] A conductive pigment paste according to a first aspect of the present invention contains a pigment dispersion resin (A), a conductive pigment (B), a solvent (C), and a fluororesin (D), wherein the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups, and the concentration of the polar functional group of the pigment dispersion resin (A) is 10 to 23 mmol / g, the average primary particle size of the conductive pigment (B) is 10 to 80 nm, the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) are in the relationship |δA-δC|<2.0, and the shear rate is 0.1 s. -1 The viscosity is less than 5000 mPa·s.

[0011] <Pigment-dispersed resin (A)> The pigment dispersion resin (A), which can be used as a component of the conductive pigment paste according to the first aspect of the present invention, contains at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups. Furthermore, the concentration of the polar functional group in the resin (A) is usually 10 to 23 mmol / g, preferably 11 to 22.5 mmol / g, and more preferably 12 to 22 mmol / g, from the viewpoint of pigment dispersibility, storage stability, and compatibility with the solvent.

[0012] Furthermore, the solubility parameter δA of the pigment dispersion resin (A) is preferably 9.3 or higher, more preferably 10.0 to 13.0, and even more preferably 11.0 to 12.5, from the viewpoint of pigment dispersibility, storage stability, and compatibility with the solvent. The solubility parameter of a resin is numerically quantified based on turbidity measurement methods known to those skilled in the art, and specifically, it can be determined according to the formula of KWSUH and JMCORBETT (Journal of Applied Polymer Science, 12, 2359, 1968). When there are two or more types of pigment-dispersing resins (A), the "solubility parameter δA of pigment-dispersing resins (A)" is the sum of the values ​​obtained by multiplying the solubility parameter value of each resin by its mass fraction.

[0013] The types of resins include resins other than fluororesins (D), specifically, acrylic resins, polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, polyvinyl acetate, silicone resins, polycarbonate resins, silicate resins, chlorine-based resins, and composite resins thereof. These resins can be used individually or in combination of two or more types. In particular, from the viewpoint of imparting sufficient film-forming properties to the conductive coating film without reducing the excellent conductivity of the conductive coating film formed from the paste or coating material, it is preferable that the pigment dispersion resin (A) contains a vinyl (co)polymer (A-1) obtained by polymerizing or copolymerizing a monomer containing a polymerizable unsaturated group-containing monomer of the following formula (1). Note that the "(co)polymer" of the present invention includes both polymers obtained by polymerizing one type of monomer and copolymers obtained by copolymerizing two or more types of monomers. C(-R)2=C(-R)2...Equation (1) [In the above formula, R may be the same or different, and is either a hydrogen atom or an organic group.]

[0014] The vinyl (co)polymer (A-1) described above is preferably one that contains a structural unit represented as "-CH2-CH(-X)-" in its structure (where X is an organic group having a polar functional group), and the polar functional group X in the structural unit is at least one polar functional group selected from the group consisting of an amide group, an imide group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, an amino group, and a cyano group. Examples of the vinyl(co)polymer (A-1) mentioned above include hydroxyl group-containing vinyl(co)polymers, carboxyl group-containing vinyl(co)polymers, pyrrolidone group-containing vinyl(co)polymers, amide group-containing vinyl(co)polymers, sulfonic acid group-containing vinyl(co)polymers, phosphate group-containing vinyl(co)polymers, and amino group-containing vinyl(co)polymers. These (co)polymers can be used individually or in combination of two or more types.

[0015] Examples of hydroxyl group-containing vinyl (co)polymers include polyhydroxyethyl (meth)acrylate, polyvinyl alcohol, vinyl alcohol-fatty acid vinyl copolymer, vinyl alcohol-ethylene copolymer, vinyl alcohol-(N-vinylformamide) copolymer, and copolymers of hydroxyethyl (meth)acrylate with other polymerizable unsaturated monomers. The vinyl alcohol units in the (co)polymer may be obtained by hydrolysis after (co)polymerization of fatty acid vinyl units. Examples of carboxyl group-containing vinyl (co)polymers include polymers of (meth)acrylic acid, or copolymers of poly(meth)acrylic acid with other polymerizable unsaturated monomers. Examples of pyrrolidone group-containing vinyl(co)polymers include polyvinylpyrrolidone, N-vinyl-2-pyrrolidone-ethylene copolymer, and N-vinyl-2-pyrrolidone-vinyl acetate copolymer. Examples of amide group-containing vinyl (co)polymers include polymers of (meth)acrylamide, or copolymers of (meth)acrylamide with other polymerizable unsaturated monomers. Examples of sulfonic acid group-containing vinyl (co)polymers include polymers of allyl sulfonic acid or styrene sulfonic acid, and copolymers of allyl sulfonic acid and / or styrene sulfonic acid with other polymerizable unsaturated monomers. Examples of phosphate-containing vinyl (co)polymers include polymers of (meth)acryloyloxyalkyl acid phosphates, or copolymers of (meth)acryloyloxyalkyl acid phosphates with other polymerizable unsaturated monomers. Examples of amino group-containing vinyl (co)polymers include polymers of polyvinylamine, polyallylamine, dimethylaminoethyl (meth)acrylate, or copolymers of dimethylaminoethyl (meth)acrylate with other polymerizable unsaturated monomers. Examples of cyano group-containing vinyl (co)polymers include polymers of acrylonitrile, or copolymers of acrylonitrile with other polymerizable unsaturated monomers.

[0016] Among these vinyl(co)polymers (A-1), hydroxyl group-containing polyvinyl(co)polymers, carboxyl group-containing polyvinyl(co)polymers, and pyrrolidone group-containing polyvinyl(co)polymers are preferred from the viewpoint of improving pigment dispersibility and reducing the surface resistivity of the conductive coating film, hydroxyl group-containing polyvinyl(co)polymers are more preferred, and polyvinyl alcohol(co)polymers are even more preferred. Furthermore, the vinyl (co)polymer (A-1) may, as necessary, contain structural units derived from copolymerizable polymerizable unsaturated group-containing monomers, in addition to the structural unit represented by "-CH2-CH(-X)-" above. Examples of copolymerizable polymerizable unsaturated group-containing monomers include vinyl carboxylate monomers such as vinyl formate, vinyl acetate, vinyl propionate, isopropenyl acetate, vinyl valerate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl versaticate, and vinyl pivalate; olefins such as ethylene, propylene, and butylene; aromatic vinyls such as styrene and α-methylstyrene; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dimethyl fumarate, dimethyl maleate, diethyl maleate, and itacone. Examples include ethylenically unsaturated carboxylate alkyl monomers such as diisopropyl acid; vinyl ether monomers such as methyl vinyl ether, n-propyl vinyl ether, isobutyl vinyl ether, and dodecyl vinyl ether; ethylenically unsaturated nitrile monomers such as (meth)acrylonitrile; vinyl halogenated monomers or vinylidene monomers such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; quaternary ammonium group-containing monomers such as 3-(meth)acrylamidopropyltrimethylammonium chloride; and vinyltrimethoxysilane, N-vinylformamide, and methacrylamide. These monomers can be used individually or in combination of two or more.

[0017] The polymerization method for the above vinyl (co)polymer (A-1) can be a known polymerization method, and while solution polymerization is preferred, it is not limited to this, and bulk polymerization, emulsion polymerization, suspension polymerization, etc., may also be used. When performing solution polymerization, it may be continuous polymerization or batch polymerization, and the monomers may be charged all at once, charged in portions, or added continuously or intermittently. The polymerization initiators used in solution polymerization are not particularly limited, but specifically, for example, azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylpaleronitrile, and azobis(4-methoxy-2,4-dimethylpaleronitrile); peroxides such as acetyl peroxide, benzoyl peroxide, lauroyl peroxide, acetylcyclohexylsulfonyl peroxide, and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate; percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate; perester compounds such as t-butyl peroxyneodecanate, α-cumyl peroxyneodecanate, and t-butyl peroxypivalate; and known radical polymerization initiators such as azobisdimethylvaleronitrile and azobismethoxyvaleronitrile can be used. The polymerization reaction temperature is not particularly limited, but it can usually be set within a range of approximately 30 to 200°C.

[0018] The vinyl (co)polymer (A-1) obtained in this way preferably has a degree of polymerization of 100 to 4,000, and more preferably 100 to 3,000 or 150 to 700. Furthermore, the weight-average molecular weight is preferably 1,000 to 200,000, and more preferably 2,000 to 100,000 or 7,000 to 30,000. The above vinyl (co)polymer (A-1) can be converted into a solid or a resin solution in any solvent by desolvent removal and / or solvent replacement after the synthesis is complete. Desolvation can be carried out by heating at atmospheric pressure or by desolvation under reduced pressure. Regarding solvent replacement, the replacement solvent may be added before, during, or after desolvation.

[0019] <Conductive pigment (B)> The conductive pigment (B) that can be used in the conductive pigment paste according to the first aspect of the present invention is not particularly limited as long as it can impart conductivity to the formed coating film and is not a carbon nanotube (F) as described later. There are also no particular restrictions on its shape, and pigments of various shapes such as particulate, flake, and fibrous (including whisker) forms can be cited. Specifically, examples include conductive carbon; metal powders such as silver, nickel, copper, graphite, and aluminum; and further, pigments coated with antimony-doped tin oxide, phosphorus-doped tin oxide, needle-shaped titanium oxide surface-coated with tin oxide / antimony, antimony oxide, zinc antimonate, indium tin oxide, carbon or graphite whiskers, etc.; pigments coated with at least one conductive metal oxide selected from the group consisting of tin oxide, antimony-doped tin oxide, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), phosphorus-doped tin oxide, and nickel oxide on the surface of flake-shaped mica; and conductive pigments containing tin oxide and phosphorus on the surface of titanium dioxide particles. Each of the above conductive pigments (B) can be used individually or in combination of two or more.

[0020] The average primary particle size of the conductive pigment (B) is preferably in the range of 10 to 80 nm, more preferably in the range of 20 to 80 nm, even more preferably in the range of 31 to 80 nm, and particularly preferably in the range greater than 31 and 52 nm or less, based on the relationship between viscosity and conductivity. Here, the average primary particle diameter in this invention refers to the average diameter of primary particles obtained by observing the pigment with an electron microscope, determining the projected area of ​​100 particles, calculating the diameter of a circle equal to that area, and then simply averaging the diameters of the 100 particles. If the pigment is in an aggregated state, the calculation is performed using the primary particles that constitute the aggregated particles. The BET specific surface area of ​​the above conductive pigment (B) is typically 250 m², considering the relationship between viscosity and conductivity. 2 It is less than / g and 10-250m 2It is preferable that the range is within / g, and 20 to 200m 2 It is more preferable that the range is within / g, and 30 to 150m 2 It is even more preferable that the range is within / g, specifically 30-110m 2 It is particularly preferable that the range be within / g. In particular, conductive pigment (B) has a specific surface area of ​​250 2 It is preferable that the product contains more than 80% conductive pigments of 1 / g or less. The amount of dibutyl phthalate (DBP) absorbed by the conductive pigment (B) described above is preferably in the range of 60 to 1,000 ml / 100 g, and more preferably in the range of 150 to 800 ml / 100 g, considering the relationship between pigment dispersibility and conductivity.

[0021] The conductive pigment (B) described above is preferably basic due to its pigment dispersibility, and specifically, it is preferably pH 7.5 or higher, more preferably 8.0 to 12.0, and even more preferably 8.5 to 11.0. Furthermore, from the viewpoint of conductivity, the conductive pigment (B) is preferably in a state where the primary particles form a chain-like structure, more preferably with a structure index in the range of 1.5 to 4.0, and particularly preferably in the range of 1.7 to 3.2. While the structure itself can be observed relatively easily in images taken with an electron microscope, the structure index is a numerical value that quantifies the degree of structure. The structure index is generally calculated by multiplying the DBP oil absorption (ml / 100g) by the specific surface area (m²). 2 It can be defined as the value obtained by dividing by ( / g). If the structure index is less than 1.5, sufficient conductivity cannot be obtained because the structure is not well developed. If it exceeds 4.0, the conductive pathways will decrease because the particle size is large relative to the DBP oil absorption amount, resulting in insufficient conductivity or potentially increasing the viscosity of the coating material.

[0022] The content of the conductive pigment (B) is preferably 5 to 99.9% by mass, more preferably 7 to 95% by mass, and particularly preferably 10 to 90% by mass, based on the total solid content of the conductive pigment paste, from the viewpoint of conductivity and pigment dispersibility. As for the type of conductive pigment (B) mentioned above, conductive carbon (B-1) can be used particularly suitably. Specifically, it is preferable that it be at least one selected from the group consisting of, for example, acetylene black, Ketjen black, furnace black, thermal black, graphene, and graphite. These conductive pigments (B) can be used individually or in combination of two or more. In particular, acetylene black (B-2) is preferred as the conductive carbon (B-1). When using acetylene black (B-2), it is preferable that it be contained in the conductive pigment (B) in an amount of 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Furthermore, as the conductive pigment (B) mentioned above, only one type of acetylene black (B-2) can be used, or two or more types of acetylene black (B-2) can be used in combination.

[0023] When the conductive carbon (B-1) is included, its content is preferably 60% by mass or more, more preferably 70-99% by mass, and even more preferably 80-99% by mass, based on the solid content mass of the pigment dispersion resin (A) and conductive carbon (B-1) of the conductive pigment paste, from the viewpoint of conductivity and pigment dispersibility.

[0024] <Solvent (C)> The solvent (C) that can be used in the conductive pigment paste of the present invention can be any conventionally known solvent without particular limitation. Specifically, for example, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, and cyclobutane; aromatic solvents such as toluene and xylene; ketone solvents such as methyl isobutyl ketone; ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol; ethyl acetate, n-butyl acetate, isobutyl acetate, and ethylene glycol monomethyl ether acetate. Examples of suitable solvents include ester solvents such as butylcarbitol acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone; alcohol solvents such as ethanol, isopropanol, n-butanol, sec-butanol, and isobutanol; and amide solvents such as equamide (trade name, manufactured by Idemitsu Kosan Co., Ltd., amide solvent), N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methylacetamide, N-methylpropioamide, and N-methyl-2-pyrrolidone, among which N-methyl-2-pyrrolidone is preferred. These solvents can be used individually or in combination of two or more.

[0025] The solvent (C) that can be used in the conductive pigment paste of the present invention preferably contains a solvent having polar functional groups such as hydroxyl groups, carboxyl groups, amide groups, amino groups, and ether groups, from the viewpoint of the solubility of the pigment dispersion resin (A) and the storage stability of the conductive pigment paste. Furthermore, from the viewpoint of preventing pigment dispersibility of the conductive pigment paste and alteration or hydrolysis of the resin, it is preferable that the paste be substantially water-free. Here, "substantially water-free" means that, based on the total amount of conductive pigment paste, the water content is usually 1% by mass or less, preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less. In this invention, the water content of the conductive pigment paste can be measured by Karl Fischer coulometric titration. Specifically, a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd., product name: MKC-610) is used, and the moisture vaporizer (manufactured by Kyoto Electronics Manufacturing Co., Ltd., product name: ADP-611) attached to the device is set to a temperature of 130°C for measurement.

[0026] Furthermore, from the viewpoint of the solubility of the pigment dispersion resin (A) and the storage stability of the conductive pigment paste, the solubility parameter (SP value) of the solvent (C) should be 10.0 (cal / cm³). 3 ) 1 / 2 Preferably, it should be 10.4 to 15.0 (cal / cm³). 3 ) 1 / 2 It is more preferable that the range be 10.5 to 13.0 (cal / cm³). 3 ) 1 / 2 It is even more preferable that it be within the range. Here, the solubility parameter, also commonly called the SP value (solubility parameter), is a measure that indicates the degree of hydrophilicity or hydrophobicity (polarity) of a solvent or resin. It is also an important measure for determining the solubility and compatibility between a solvent and a resin, and between resins. Generally, when the solubility parameter values ​​are close (the absolute value of the difference in solubility parameters is small), the solubility and compatibility are good.

[0027] The solubility parameter of a solvent can be determined according to the method described in "Polymer Handbook" VII Solubility Parameter Values, pp. 519-559, edited by J. Brandrup and E. Himmmergut (John Wiley & Sons, 3rd edition, 1989). When two or more solvents are combined to form a mixed solvent, the solubility parameter of the mixed solvent can be determined experimentally, or, as a simpler method, by summing the products of the mole fractions of each liquid solvent and their solubility parameters. In this invention, the "solubility parameter of solvent (C)" refers to the solubility parameter of all solvents (mixed solvents) contained in the conductive pigment paste. In the conductive pigment paste of the present invention, from the viewpoint of solubility, viscosity and pigment dispersibility, it is preferable that the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) have a relationship of |δA-δC| < 2.0, and more preferably |δA-δC| < 1.5.

[0028] <Fluororesin (D)> The fluororesin (D) that can be used in the conductive pigment paste of the present invention is a resin intended for film formation of a coating film, and is a low-polarity resin that substantially does not contain the polar functional groups that are essential components of the pigment dispersion resin (A). For example, the concentration of polar functional groups is less than 10 mmol / g, preferably 5 mmol / g or less, and more preferably 1 mmol / g or less. Polyvinylidene fluoride (PVDF) is particularly preferred as the fluororesin (D), and one type can be used alone or two or more types can be used in combination. The fluororesin (D) may be included during pigment dispersion or added after pigment dispersion. The weight-average molecular weight of the fluororesin (D) is preferably 100,000 or more, more preferably 500,000 to 3,000,000, and particularly preferably 650,000 to 2,000,000, from the viewpoint of adhesion to the substrate, reinforcement of the coating film properties, and solvent resistance.

[0029] The solubility parameter of fluororesin (D) is preferably less than 10, and more preferably less than 9.3. Furthermore, from the viewpoint of resin solubility and storage stability, it is preferable that the solubility parameter δD of the fluororesin (D) and the solubility parameter δC of the solvent (C) are in a relationship of |δD-δC| < 3.0. More preferably, it is 0 ≤ |δD-δC| ≤ 2.8, and even more preferably 0.1 ≤ |δD-δC| ≤ 2.5.

[0030] <High polar low molecular weight component (E)> The conductive pigment paste of the present invention preferably contains the following highly polar, low molecular weight component (E) from the viewpoint of improving the wettability and / or storage stability of the conductive pigment. The above-mentioned highly polar, low molecular weight component (E) is preferably basic or acidic, and may be partially or entirely a salt. In particular, the highly polar, low molecular weight component (E) is more preferably one that contains at least one amine compound (E1) from the viewpoint of improving the wettability and / or storage stability of the conductive pigment. Examples of the above amine compound (E1) include ammonia, primary amines, secondary amines, tertiary amines, etc.

[0031] Primary amines include, for example, ethylamine, n-propylamine, sec-propylamine, n-butylamine, sec-butylamine, i-butylamine, tert-butylamine, pentylamine, hexylamine, heptylamine, octylamine, decylamine, laurylamine, mystyrylamine, 1,2-dimethylhexylamine, 3-pentylamine, 2-ethylhexylamine, allylamine, aminoethanol, 1-aminopropanol, 2-aminopropanol, aminobutanol, aminopentanol, aminohexanol, 3-ethoxypropylamine, 3-propoxypropylamine, 3-isopropoxypropylamine, 3-butoxypropylamine, 3-isobutoxypropylamine, 3-(2-ethylhexyloxy)propylamine, aminocyclopentane, aminocyclohexane, aminonorbornene, aminomethylcyclohexane, aminobenzene (aniline), benzylamine, phenethylamine, α-phenylethylamine, naphthylamine Primary monoamines such as methylamine and furfurylamine; ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,2-diaminobutane, 1,3-diaminobutane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, dimethylaminopropylamine, diethylaminopropylamine, bis-(3-aminopropyl) ether, 1,2-bis-(3-aminopropoxy)ethane, 1,3- S-(3-aminopropoxy)-2,2'-dimethylpropane, aminoethylethanolamine, 1,2-bisaminocyclohexane, 1,3-bisaminocyclohexane, 1,4-bisaminocyclohexane, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, 1,3-bisaminoethylcyclohexane, 1,4-bisaminoethylcyclohexane, 1,3-bisaminopropylcyclohexane, 1,4-bisaminopropylcyclohexane, hydrogenated 4,4'-Diaminodiphenylmethane, 2-Aminopiperidine, 4-Aminopiperidine, 2-Aminomethylpiperidine, 4-Aminomethylpiperidine, 2-Aminoethylpiperidine, 4-Aminoethylpiperidine, N-Aminoethylpiperidine, N-Aminopropylpiperidine, N-Aminoethylmorpholine, N-Aminopropylmorpholine, Isophoronediamine, Menthanediamine, 1,4-Bisaminopropylpiperazine, o-Phenylenediamine, m-Phenylenediamine, p-Phenylenediamine, 2,4-Tolylenediamine, 2,6-Tolylenediamine, 2,4-Toluenediamine, m-Aminobenzylamine, 4-Chloro-o-Phenylenediamine, Tetrachloro-p-Xylylenediamine, 4-Methoxy-6-methyl-m-Phenylenediamine, m-Xylylenediamine, p-Xylylenediamine, 1,5-Naphthalenediamine, 2,6-Naphthalenediamine, Benzidine, 4,4'-Bis( o-Toluidine), dianisidine, 4,4'-diaminodiphenylmethane, 2,2-(4,4'-diaminodiphenyl)propane, 4,4'-diaminodiphenyl ether, 4,4'-thiodianiline, 4,4'-diaminodiphenylsulfone, 4,4'-diaminoditolylsulfone, methylenebis(o-chloroaniline), 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro[5,5]undecane, diethylenetriamine, Examples include primary polyamines such as iminobispropylamine, methyliminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-aminoethylpiperazine, N-aminopropylpiperazine, 1,4-bis(aminoethylpiperazine), 1,4-bis(aminopropylpiperazine), 2,6-diaminopyridine, and bis(3,4-diaminophenyl)sulfone.

[0032] Examples of secondary amines include secondary monoamines such as diethylamine, dipropylamine, di-n-butylamine, di-sec-butylamine, diisobutylamine, di-n-pentylamine, di-3-pentylamine, dihexylamine, dioctylamine, di(2-ethylhexyl)amine, methylhexylamine, diallylamine, pyrrolidine, piperidine, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, diphenylamine, N-methylaniline, N-ethylaniline, dibenzylamine, methylbenzylamine, dinaphthylamine, pyrrole, indoline, indole, and morpholine; N,N'-dimethylethylenediamine, N,N'-dimethyl-1,2-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N,N'-dimethyl-1,2-diaminobutane, N,N'-dimethyl-1,3-diaminobutane, N,N' -Dimethyl-1,4-diaminobutane, N,N'-dimethyl-1,5-diaminopentane, N,N'-dimethyl-1,6-diaminohexane, N,N'-dimethyl-1,7-diaminoheptane, N,N'-diethylethylenediamine, N,N'-diethyl-1,2-diaminopropane, N,N'-diethyl-1,3-diaminopropane, N,N'-diethyl-1,2-diaminobutane, N,N'-diethyl-1,3-diaminobutane Examples include secondary polyamines such as N,N'-diethyl-1,4-diaminobutane, N,N'-diethyl-1,6-diaminohexane, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, homopiperazine, 1,1-di-(4-piperidyl)methane, 1,2-di-(4-piperidyl)ethane, 1,3-di-(4-piperidyl)propane, and 1,4-di-(4-piperidyl)butane.

[0033] Examples of tertiary amines include trimethylamine, triethylamine, tri-n-propylamine, tri-iso-propylamine, tri-1,2-dimethylpropylamine, tri-3-methoxypropylamine, tri-n-butylamine, tri-iso-butylamine, tri-sec-butylamine, tri-pentylamine, tri-3-pentylamine, tri-n-hexylamine, tri-n-octylamine, tri-2-ethylhexylamine, tri-dodecylamine, tri-laurylamine, dicyclohexylethylamine, cyclohexyldiethylamine, tricyclohexylamine, N,N-dimethylhexylamine, N-methyldihexylamine, N,N-dimethylcyclohexylamine, N-methyldicyclohexylamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, N-ethyldiethanolamine, triethanolamine, tribenzylamine, N,N-dimethylbenzylamine, diethylbenzylamine Tertiary monoamines such as dilamines, triphenylamine, N,N-dimethylamino-p-cresol, N,N-dimethylaminomethylphenol, 2-(N,N-dimethylaminomethyl)phenol, N,N-dimethylaniline, N,N-diethylaniline, pyridine, quinoline, N-methylmorpholine, N-methylpiperidine, 2-(2-dimethylaminoethoxy)-4-methyl-1,3,2-dioxabornane, 2-,3-,4-picoline, etc.; tetramethylethylenediamine Examples include pyrazine, N,N'-dimethylpiperazine, N,N'-bis((2-hydroxy)propyl)piperazine, hexamethylenetetramine, N,N,N',N'-tetramethyl-1,3-butanamine, 2-dimethylamino-2-hydroxypropane, diethylaminoethanol, N,N,N-tris(3-dimethylaminopropyl)amine, 2,4,6-tris(N,N-dimethylaminomethyl)phenol, and tertiary polyamines such as heptamethylisobiguanide. These can be used individually or in combination of two or more types.

[0034] In particular, it is preferable that the compound does not contain other functional groups such as acid groups or hydroxyl groups, and a primary amine compound is preferred, and a monovalent amine compound (monoamine) is preferred. Examples of the above-mentioned amine compound (E1) include aliphatic amines, alicyclic amines, and aromatic amines, all of which can be suitably used, but aromatic amines are preferred. Since it is preferable that no amine compound remains in the coating film after drying, the weight-average molecular weight of the amine compound (E1) is preferably less than 1000, more preferably 800 or less, even more preferably 500 or less, and particularly preferably 200 or less. For the same reason, the boiling point of the amine compound is preferably 400°C or less, more preferably 300°C or less, and even more preferably 200°C or less. Furthermore, the amine value of the amine compound (E1) is preferably in the range of 5 to 1000 mg KOH / g, more preferably 50 to 1000 mg KOH / g, and more preferably 105 to 1000 mg KOH / g.

[0035] Other highly polar, low molecular weight components may include, for example, one or more acidic highly polar, low molecular weight components selected from organic acids and inorganic acids. Additionally, one or more basic highly polar, low molecular weight components selected from organic bases and inorganic bases may be used. Examples of organic acids include organic carboxylic acids (formic acid, acetic acid, propionic acid, benzoic acid, phthalic acid, etc.) and organic sulfonic acids (benzenesulfonic acid, etc.), while examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. Examples of organic bases include basic components other than amine compounds, while examples of inorganic bases include metal hydroxides (such as sodium hydroxide and potassium hydroxide).

[0036] The lower limit of the content of the above-mentioned highly polar, low molecular weight component (E) is, from the viewpoint of improving the wettability and / or storage stability of the conductive pigment, usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 3% by mass or more, even more preferably 20% by mass or more, and particularly preferably 80% by mass or more, based on 100% by mass of the solid content of the conductive pigment (B). The upper limit of the content is usually 500% by mass or less, preferably 450% by mass or less, more preferably 400% by mass or less, even more preferably 350% by mass or less, and particularly preferably 300% by mass or less.

[0037] <Other ingredients> The conductive pigment paste according to the first aspect of the present invention may contain, as necessary, other components in addition to the pigment dispersion resin (A), conductive pigment (B), solvent (C), and highly polar, low molecular weight component (E) described above. Other components include resins other than pigment-dispersing resin (A) and fluororesin (D), low molecular weight components other than high-polarity low molecular weight components (E), neutralizing agents, defoaming agents, preservatives, rust inhibitors, plasticizers, and pigments other than conductive pigments (B) and carbon nanotubes (F). Examples of resins other than pigment-dispersing resin (A) and fluororesin (D) include acrylic resins other than resins (A) and (D), polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, silicone resins, polycarbonate resins, silicate resins, chlorine-based resins, polyvinylpyrrolidone resins, polyvinyl alcohol resins, polyvinyl acetal resins, styrene-based resins, diene-based resins, polyolefin-based resins, and composite resins thereof. These resins can be used individually or in combination of two or more types.

[0038] Examples of pigments other than conductive pigments (B) and carbon nanotubes (F) include white pigments such as titanium white and zinc oxide; blue pigments such as cyanine blue and induthlene blue; green pigments such as cyanine green and verdigris; organic red pigments such as azo and quinacridone, and red pigments such as red iron oxide; organic yellow pigments such as benzimimidazolone, isoindolinone, isoindoline, and quinophthalone, and yellow pigments such as titanium yellow and lead yellow. These pigments can be used individually or in combination of two or more. These pigments other than conductive pigments (B) and carbon nanotubes (F) can be used for purposes such as color adjustment and reinforcement of film properties within a range that does not significantly impair conductivity, and may be dispersed together with the pigment dispersion resin (A) and conductive pigment (B), or they may be mixed as a pigment or pigment paste after a paste has been prepared by dispersing the pigment dispersion resin (A) and conductive pigment (B). The content of pigments other than the conductive pigment (B) and carbon nanotube (F) described above is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and particularly preferably substantially absent, based on the total pigment in the conductive pigment paste.

[0039] The solid content of the pigment dispersion resin (A) in the conductive pigment paste is preferably 30% by mass or less, more preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass, based on the total solid content of the paste, from the viewpoint of viscosity during pigment dispersion, pigment dispersibility, storage stability, production efficiency, and conductivity.

[0040] The particle size distribution of the conductive pigment (B) in the conductive pigment paste obtained with the above composition is preferably such that the frequency distribution curve obtained by over-diluting the conductive pigment paste with solvent (C) and measuring the volume-based particle size distribution by laser diffraction scattering has at least two peaks, with at least one peak top in the particle size range of 150 to 550 nm and at least one peak top in the particle size range of 600 to 3000 nm. The peak area ratio in the particle size range (total peak area in the particle size range of 150 to 550 nm / total peak area in the particle size range of 600 to 3000 nm) is preferably 0.2 to 3, more preferably 0.3 to 2.7, and even more preferably 0.4 to 2.4. The particle size distribution of the conductive pigment (B) has at least two peaks, and by satisfying the above conditions, the conductive pigment in the conductive pigment paste can form a structure while having appropriate fluidity, and the conductive coating film or conductive material can obtain good finish and conductivity.

[0041] If dispersion is weak and the frequency (sum of peak areas) of peak tops increases on the large particle size side (particle size range of 600-3000 nm), while the frequency (sum of peak areas) of peak tops on the small particle size side (particle size range of 150-550 nm) decreases or disappears, fluidity may decrease. Conversely, if dispersion is strong and the frequency (sum of peak areas) of peak tops on the small particle size side (particle size range of 150-550 nm) increases, while the frequency (sum of peak areas) of peak tops on the large particle size side (particle size range of 600-3000 nm) decreases or disappears, conductivity will decrease. In this invention, volume-based particle size distribution measurement by laser diffraction scattering was performed using a particle size distribution analyzer (Microtrac MT3000, manufactured by Microtrac-Bell).

[0042] Furthermore, the average particle size (D50) obtained by diluting the conductive pigment paste with a solvent and measuring the volume-based particle size distribution by laser diffraction scattering is preferably in the range of 400 to 1,500 nm, more preferably in the range of 860 to 1,400 nm, and even more preferably in the range of 900 to 1,250 nm.

[0043] Furthermore, when the average particle size (D50) of the primary particles of the conductive pigment (B) is set to 1, the average particle size (D50) obtained by diluting the conductive pigment paste with a solvent and measuring the volume-based particle size distribution by laser diffraction scattering is preferably 15 to 30, and more preferably 18 to 25. In other words, the "particle size ratio," which is the ratio of the average particle size (D50) to the average primary particle size of the conductive pigment, is defined as the secondary particle size. Particle size ratio = average secondary particle size (nm) / average primary particle size (nm) When calculated using this method, the particle size ratio is preferably 15 to 30, and more preferably 18 to 25. Furthermore, in the above particle size distribution measurement, if a pigment other than conductive pigment (B) is contained in the conductive pigment paste, the conductive pigment paste prepared using only conductive pigment (B) shall be measured.

[0044] The viscosity of the above conductive pigment paste is determined from the viewpoint of pigment dispersibility and storage stability to be a shear rate of 0.1 s. -1 The viscosity is less than 5000 mPa·s, preferably 10 mPa·s or more and less than 5000 mPa·s, more preferably 50 mPa·s or more and less than 2500 mPa·s, and particularly preferably 100 mPa·s or more and less than 1100 mPa·s. Viscosity can be measured using, for example, a cone and plate viscometer (HAAKE, product name Mars2, 35mm diameter, 2° inclined cone and plate).

[0045] The conductive pigment paste of the present invention can be prepared by uniformly mixing and dispersing each of the above-mentioned components using conventionally known dispersion machines such as a paint shaker, sand mill, ball mill, pebble mill, LMZ mill, DCP pearl mill, planetary ball mill, homogenizer, twin-screw kneader, or thin-film swirling high-speed mixer (product names: Creamix, Filmix, etc.). Furthermore, in terms of dispersion, from the viewpoint of the conductivity of the conductive coating film, it is preferable that the particle size distribution of the conductive pigment (B) has two peaks. Therefore, it is preferable that it is not finely dispersed down to primary particles, and it is preferable to disperse it substantially without using a mediator. In the present invention, a method for dispersing a conductive pigment paste can be established by dispersing the conductive pigment paste substantially without using a mediator when manufacturing a conductive pigment paste according to the first embodiment.

[0046] <Conductive pigment paste (second embodiment)> A conductive pigment paste according to a second aspect of the present invention can be obtained by mixing the conductive pigment paste according to the first aspect with carbon nanotubes (F). In the conductive pigment paste according to a second aspect of the present invention, the conductive pigment (B) is preferably one or more types of acetylene black (B-2). The conductive pigment paste according to the second aspect of the present invention provides even better conductivity by containing the above-mentioned carbonan tube (F). Furthermore, even better conductivity can be obtained by containing acetylene black (B-2). The method for mixing the conductive pigment paste according to the first embodiment with the carbon nanotube (F) is not particularly limited. For example, a liquid carbon nanotube dispersion paste may be prepared using the carbon nanotube in the same manner as the method for preparing the conductive pigment paste according to the first embodiment, and this may be mixed with the conductive pigment paste according to the first embodiment. For example, the carbon nanotube itself may be mixed with the conductive pigment paste according to the first embodiment. For example, when dispersing the pigment in the conductive pigment paste according to the first embodiment, the conductive pigment (B) and the carbon nanotube (F) may be dispersed together. Furthermore, the aforementioned highly polar, low molecular weight component (E) can also be included in the conductive pigment paste according to the second embodiment, and there are no particular restrictions on the order in which they are mixed.

[0047] The solid content ratio of conductive pigment (B) to carbonan tube (F) is usually in the range of 1 / 99 to 99 / 1, preferably in the range of 50 / 50 to 99 / 1. Acetylene black (B-2) is preferred as the conductive pigment (B). In the conductive pigment paste according to the second embodiment, the carbon nanotube (F) content is preferably 0.1 to 99% by mass, and more preferably 0.5 to 50% by mass, based on the total solid content of the conductive pigment paste, from the viewpoint of conductivity and pigment dispersibility. Furthermore, in the conductive pigment paste according to the second embodiment, similar to the conductive pigment paste according to the first embodiment, the shear rate is 0.1 s. -1 The viscosity is less than 5000 mPa·s, preferably 10 mPa·s or more and less than 5000 mPa·s, more preferably 50 mPa·s or more and less than 2500 mPa·s, and particularly preferably 100 mPa·s or more and less than 1200 mPa·s.

[0048] As the carbon nanotube (F) mentioned above, single-walled carbon nanotubes or multi-walled carbon nanotubes can be used individually or in combination. In particular, due to the relationship between viscosity, conductivity, and cost, it is preferable to use multi-walled carbon nanotubes. The outer diameter of the carbon nanotube (F) is preferably 1 to 25 nm, more preferably 3 to 20 nm, and particularly preferably 5 to 15 nm. The length of the carbon nanotube (F) is preferably 1 to 100 μm, more preferably 5 to 80 μm, and particularly preferably 10 to 60 μm. The specific surface area of ​​the above carbon nanotube (F) is estimated to be between 1 and 1000 m² based on its viscosity and conductivity. 2 It is preferably within the range of / g, 10 to 500m 2 It is even more preferable that the range be within / g. Carbon nanotubes that have undergone surface treatment such as oxidation treatment have high pigment dispersibility, but their conductivity is poor due to surface defects that occur during the surface treatment process. Therefore, from the viewpoint of conductivity, carbon nanotubes (F) that have not undergone surface treatment are preferred.

[0049] Furthermore, the conductive pigment paste of the second embodiment also preferably contains the aforementioned high-polarity low-molecular-weight component (E), and it is more preferable that the high-polarity low-molecular-weight component (E) contains at least one amine compound (E1). The lower limit of the content of the highly polar, low molecular weight component (E) in the conductive pigment paste of the second embodiment is, from the viewpoint of improving the wettability and / or storage stability of the conductive pigment and carbon nanotubes (F), usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 3% by mass or more, even more preferably 20% by mass or more, and particularly preferably 80% by mass or more, based on 100% by mass of the solid content of the conductive pigment (B) and carbon nanotubes (F). The upper limit of the content is usually 500% by mass or less, preferably 450% by mass or less, more preferably 400% by mass or less, even more preferably 350% by mass or less, and particularly preferably 300% by mass or less.

[0050] [Coating materials] The coating material of the present invention contains a conductive pigment paste according to the first embodiment and / or a conductive pigment paste according to the second embodiment, and metal-containing particles (G) having at least one metal element. The coating material of the present invention may further be a mixture of conductive pigment paste with various components such as other resins, other pigments, solvents, and additives, as needed. Other resins include those not included in the conductive pigment paste, such as acrylic resins, polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, silicone resins, polycarbonate resins, silicate resins, chlorine-based resins, polyvinylpyrrolidone resins, polyvinyl alcohol resins, polyvinyl acetal resins, and composite resins thereof. These resins can be used individually or in combination of two or more.

[0051] In particular, the coating material of the present invention preferably contains the aforementioned high-polarity low-molecular-weight component (E) from the viewpoint of storage stability (suppression of thickening) in the coating material, and more preferably contains at least one amine compound (E1) as the high-polarity low-molecular-weight component (E). The above-mentioned highly polar, low molecular weight component (E) may be included in the conductive pigment paste that serves as the raw material for the coating material, may be added after the manufacture of the conductive pigment paste, or may be added when manufacturing the coating material by mixing the conductive pigment paste with metal-containing particles. From the viewpoint of mitigating aggregation between the conductive pigment (B) and the metal-containing particles by first bringing the highly polar, low molecular weight component (E) into contact with (wetting) the conductive pigment (B), and then mixing in the metal-containing particles, it is preferable to include the sequence of first mixing the conductive pigment (B) and the highly polar, low molecular weight component (E).

[0052] In the coating material of the present invention, the preferred lower limit of the content of the highly polar, low molecular weight component (E) is, based on 100% by mass of the solid content of the conductive pigment (B) [in the second embodiment, conductive pigment (B) and carbon nanotube (F)], usually 3% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 40% by mass or more, and particularly preferably 80% by mass or more, from the viewpoint of storage stability (thickening suppression) of the coating material. The preferred upper limit of the content is, from the viewpoint of the amount of component (E) remaining in the coating film, usually 500% by mass or less, preferably 450% by mass or less, more preferably 400% by mass or less, even more preferably 350% by mass or less, and particularly preferably 300% by mass or less.

[0053] Furthermore, if the coating material contains composite metal particles (G1) having alkali metals, as described later, it may thicken during storage. At least one of the following two reasons is thought to be the cause, and in both cases, the thickening of the coating material during storage can be suppressed by including a certain amount or more of an amine compound (E1). (1) Composite metal particles (G1) may dissolve alkali metal hydroxides (e.g., KOH, NaOH, LiOH, etc.) derived from the raw materials into the coating material, and it is thought that these strongly basic components cause reactions between the resins (pigment dispersion resins and / or fluororesins) and increase viscosity. (2) Composite metal particles (G1) may have alkali metal hydroxides on their surface, and are therefore thought to aggregate (thicken) when they have an acidic surface with conductive pigments (B) or carbon nanotubes (F).

[0054] In the coating material of the present invention, other pigments include pigments other than those contained in the metal-containing particles and conductive pigment paste described later, such as coloring pigments, lustrous pigments, extender pigments, and rust-preventive pigments. These pigments can be used individually or in combination of two or more. In particular, it is preferable to add and include metal-containing particles having at least one metal element.

[0055] <Metal-containing particles (G)> The metal-containing particles (G) contained in the coating material of the present invention are mixed with the conductive pigment paste during the manufacturing process of the coating material, and are different from the conductive pigment (B) and carbon nanotubes (F) contained in the aforementioned conductive pigment paste. The above-mentioned metal-containing particles (G) have at least one metallic element. The above-mentioned metal-containing particles (G) can be appropriately selected depending on the application of the coating film, and are preferably composite metal particles (G1) having at least one alkali metal and at least one transition metal element. Nitrides, oxides, sulfides, and / or hydroxides of these can also be suitably used, with oxides being particularly preferred. Examples of the above transition metal elements include Fe, Cu, Mn, Ni, Zr, Zn, Mo, Ag, Au, Pt, Ti, and Cr.

[0056] The average particle size of the metal-containing particles is preferably 1,501 nm or larger, more preferably 1,600 to 50,000 nm, and even more preferably 2,000 to 30,000 nm, based on the average particle size (D50) obtained by volume-based particle size distribution measurement using laser diffraction scattering after diluting the coating material with a solvent. The content of metal-containing particles in the coating material is preferably 10% by mass or more and 99% by mass or less, more preferably 15% by mass or more and 95% by mass or less, based on the total amount of solids in the coating material, from the standpoint of conductivity and coating film properties. In the present invention, a method for manufacturing a coating material can be constructed by adding metal-containing particles having at least one metal element to the conductive pigment paste according to the first embodiment and / or the conductive pigment paste according to the second embodiment.

[0057] There are no particular restrictions on the solvent, but solvents similar to solvent (C) described above can be suitably used. The above solvents can be used individually or in combination of two or more. Examples of additives include neutralizing agents, pigment dispersants, defoaming agents, preservatives, rust inhibitors, plasticizers, and viscosity modifiers. The content of the pigment dispersion resin (A) in the coating material is preferably 0.01 to 80% by mass, more preferably 0.02 to 50% by mass, more preferably 0.05 to 20% by mass, and particularly preferably 0.08 to 10% by mass, based on the total amount of solids in the coating material, in terms of viscosity during pigment dispersion, pigment dispersibility, storage stability, production efficiency, and conductivity. Furthermore, the content of the pigment dispersion resin (A) per 100 parts by mass of conductive pigment (B) is preferably 0.01 to 400 parts by mass, more preferably 0.02 to 50 parts by mass, more preferably 0.05 to 25 parts by mass, even more preferably 0.05 to 7 parts by mass, and particularly preferably 0.05 to 4.5 parts by mass, based on the total amount of solids.

[0058] The coating material can be prepared by uniformly mixing or dispersing each of the above-mentioned components using conventionally known agitators or dispersers such as dispersers, paint shakers, sand mills, ball mills, pebble mills, LMZ mills, DCP pearl mills, planetary ball mills, homogenizers, twin-screw kneaders, and thin-film swirling high-speed mixers. Among these, dispersion without the use of a mediator is preferred.

[0059] [Coating films and coating materials] The coating film of the present invention can be obtained by applying (coating) the aforementioned coating material to an object to be coated. The coating material of the present invention can be obtained by applying (coating) the aforementioned coating material to both sides of a plate-shaped substrate. In the present invention, a coating film is a solid film obtained by applying a liquid coating material to a substrate and heating and drying it. It can also be peeled off the substrate to obtain a conductive film, or coated on both sides of a plate-shaped substrate to obtain a conductive material. The shape of the object to be coated is not particularly limited and can be any shape, such as a plate, rod, film, or sphere. The material of the object to be coated or the plate-shaped substrate is not particularly limited and can include, for example, metal materials; various plastic materials; inorganic materials such as glass, cement, and concrete; wood; fibrous materials (paper, cloth, etc.), and composite materials thereof may also be used. The object to be coated or the plate-shaped substrate may be degreased, surface treated, or otherwise subjected to other appropriate treatments as needed.

[0060] The application method is not particularly limited as long as it can be applied within a certain film thickness range. Examples include roller coating, brush coating, atomization coating, dipping coating, applicator coating, shower coating, roll coater coating, and die coater coating. The film thickness is preferably 1 to 200 μm in dry thickness, and more preferably 2 to 150 μm. The drying temperature is preferably 60 to 300°C, and more preferably 80 to 200°C. It is preferable that 80% or more of the solvent contained in the coating material is eliminated by heating and drying, more preferably 90% or more, and particularly preferably 95% or more. Furthermore, if a highly polar, low molecular weight component (E) is contained, it is preferable that some or all of it is eliminated by the above heating and drying process. [Examples]

[0061] The present invention will be described in more detail below with reference to manufacturing examples, embodiments, and comparative examples, but the present invention is not limited thereto. In each example, "parts" refers to parts by mass, and "%" refers to mass percent.

[0062] [Manufacturing of conductive pigment paste] <Examples 1-32 (Conductive Pigment Paste of the First Embodiment) and Comparative Examples 1-5> The pigment dispersion resin (A), conductive pigment (B), solvent (C), fluororesin (D), and high-polarity, low-molecular-weight component (E) listed in Tables 1 to 3 were mixed in the amounts (parts by mass) listed in Table 3. Subsequently, the mixtures were dispersed for the times listed in Tables 1 to 3 using a Filmix (product name: thin-film swirling high-speed mixer, manufactured by Primix Corporation) or a ball mill to obtain conductive pigment pastes X-1 to X-32 and X-39 to X-43. Note that the resin content and conductive pigment values ​​in the tables represent the solid content.

[0063] <Examples 33-38 (Conductive Pigment Paste of the Second Embodiment)> The pigment dispersion resin (A), conductive pigment (B), solvent (C), fluororesin (D), and high-polarity, low-molecular-weight component (E) listed in Table 3 were mixed in the amounts (parts by mass) listed in Table 3, and then dispersed for the time listed in Table 3 using a film mixer (product name: film-thin swirling high-speed mixer, manufactured by Primix) or a ball mill. After that, carbon nanotubes (F) were added in the amount (parts by mass) listed in Table 3, and further dispersed for 60 minutes using a film-thin swirling high-speed mixer (product name: film mix, manufactured by Primix) to obtain conductive pigment pastes X-33 to X-38.

[0064] Tables 1 to 4 show the SP value difference, particle size (number of peaks, peak area ratio, average particle diameter (D50), particle diameter ratio), and evaluation test results (initial viscosity, dispersibility, storage stability, finish quality, conductivity) for conductive pigment pastes X-1 to X43. Note that the particle size (number of peaks, peak area ratio, average particle diameter (D50), secondary particle / primary particle ratio) values ​​for X-33 to X-38 are the values ​​measured for the paste before the addition of CNTs (carbon nanotubes). Furthermore, the water content of conductive pigment pastes X-1 to X-43 was measured by Karl Fischer coulometric titration, and all were found to be 0.1% by mass or less.

[0065] In this invention, it is important that the conductive pigment paste exhibits excellent performance in all items of the evaluation test. If any one item receives a "D" rating, the conductive pigment paste will be deemed unacceptable. Furthermore, for Comparative Examples 1, 2, 3, and 5, since one or more evaluation results for viscosity, dispersibility, and storage stability were unsatisfactory, the tests for finish quality and conductivity, which were part of the evaluation tests, were not performed.

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] [Table 4]

[0070] [Components of conductive resin paste] <Pigment-dispersed resin (A)> Resin A: Vinyl acetate-vinyl alcohol copolymer (SP value 12.0, hydroxyl group concentration 17.2 mmol / g, weight-average molecular weight 20,000, degree of saponification 89.0 mol%) Resin B: Vinyl acetate-vinyl alcohol copolymer (SP value 12.6, hydroxyl group concentration 22.7 mmol / g, weight-average molecular weight 15,000, degree of saponification 99.9 mol%) Resin C: Vinyl acetate-vinyl alcohol copolymer (SP value 10.8, hydroxyl group concentration 9.9 mmol / g, weight-average molecular weight 28,000, degree of saponification 60.0 mol%) Resin D: Polyacrylamide (SP value 12.0, amide group concentration 14.1 mmol / g, weight-average molecular weight 18,000) Resin E: Hydroxyethyl acrylate-acrylic acid copolymer (SP value 11.8, hydroxyl group concentration 4.3 mmol / g, carboxyl group concentration 6.9 mmol / g, weight-average molecular weight 13,000) Resin F: Polyacrylic acid (SP value 12.9, carboxyl group concentration 13.9 mmol / g, weight-average molecular weight 15,000) Resin G: Polymethyl methacrylate (SP value 9.2, polar group concentration 0 mmol / g, weight-average molecular weight 21,000) Resin H: Polyacrylonitrile (SP value 12.5, polar group concentration 18.9 mmol / g, weight-average molecular weight 25,000)

[0071] <Conductive pigment (B)> Conductive pigment A: Carbon black (acetylene black) (average primary particle size 25 nm, pH: 9, BET specific surface area 115 m²) 2 / g) Conductive pigment B: Carbon black (acetylene black) (average primary particle size 35 nm, pH: 9, BET specific surface area 70 m²) 2 / g) Conductive pigment C: Carbon black (acetylene black) (average primary particle size 50 nm, pH: 9, BET specific surface area 36 m²) 2 / g) Conductive pigment D: Carbon black (acetylene black) (average primary particle size 55 nm, pH: 9, BET specific surface area 28 m²) 2 / g) Conductive pigment E: Carbon black (acetylene black) (average primary particle size 90 nm, pH: 9, BET specific surface area 9 m²) 2 / g)

[0072] <Solvent (C)> NMP: N-methyl-2-pyrrolidone (SP value 11.1) DMAc: N,N-dimethylacetamide (SP value 11.2) PGME: Propylene glycol monomethyl ether (SP value 10.4) MEK: Methyl ethyl ketone (SP value 9.3)

[0073] <Fluororesin (D)> PVDF: Polyvinylidene fluoride (weight-average molecular weight: 800,000, SP value: 9.1)

[0074] <High polar low molecular weight component (E)> NaOH: Sodium hydroxide HCOOH: Formic acid Glu: Glutamic acid Be-A: Benzylamine ME-A: Methylethanolamine

[0075] <Carbon nanotubes (F)> CNT: Carbon nanotube (multilayered, average outer diameter 9 nm, average length 20 μm)

[0076] [|δA-δC|] The relationship |δA-δC| between the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) is the absolute value obtained by subtracting the SP value of the solvent (C) from the SP value of the pigment dispersion resin (A), and was calculated using the following formula. |δA - δC| = |SP value of pigment-dispersed resin (A) - SP value of solvent (C)|

[0077] [Particle size] <Number of peaks> The conductive pigment paste was diluted with the appropriate solvent, and the volume-based particle size distribution was measured using a laser diffraction scattering particle size distribution analyzer (Microtrac-Bell, product name Microtrac MT3000) to obtain a frequency distribution curve. The number of peaks in the frequency distribution curve was then counted.

[0078] <Peak Area Ratio> In the frequency distribution curve described above, the peak area ratio (total peak area in the 150-550 nm particle size range / total peak area in the 600-3,000 nm particle size range) was calculated. Note that X-32 is a single peak, so no calculation was performed, and it is indicated with an asterisk (*) in the table.

[0079] <Average particle diameter (D50)> The conductive pigment paste was diluted with a solvent, and the average particle size (D50) based on volume was calculated using laser diffraction scattering.

[0080] <Particle size ratio> The average particle diameter (D50) mentioned above was used as the average secondary particle diameter, and the ratio to the average primary particle diameter of the conductive pigment used was calculated using the following formula. Particle size ratio = average secondary particle size (nm) / average primary particle size (nm)

[0081] [Evaluation Test] <Initial viscosity> The obtained conductive pigment paste was measured using a cone and plate viscometer (HAAKE, product name Mars2, 35mm diameter, 2° inclined cone and plate) at a shear rate of 0.1s. -1 The viscosity (mPa·s) was measured.

[0082] <Dispersibility> The obtained conductive pigment paste was evaluated for dispersibility using a particle gauge according to the following criteria, in accordance with the dispersion test of JIS K-5600-2-5. S: The pigment is dispersed at a size of less than 10 μm. Dispersibility is very good. A: The pigment is dispersed at a size of 10 μm or more and less than 15 μm. Dispersibility is good. B: The pigment is dispersed at a size of 15 μm or more and less than 20 μm. The dispersibility is moderately good. C: The pigment is dispersed at a size of 20 μm or larger, but no aggregates are visible to the naked eye. Dispersibility is somewhat poor. D: Aggregates are visible to the naked eye. Dispersibility is very poor.

[0083] <Storage Stability (Conductive Pigment Paste)> The obtained conductive pigment paste was stored at 50°C for one month, and the initial viscosity and the viscosity after storage were compared. Viscosity was measured using a cone and plate viscometer (HAAKE, product name Mars2, 35 mm diameter, 2° inclined cone and plate) at a shear rate of 1.0 s². -1 The viscosity was measured, the viscosity increase rate was determined using the following formula, and the storage stability was evaluated according to the following criteria. Viscosity increase rate (%) = Viscosity after storage (mPa·s) / Initial viscosity (mPa·s) × 100 - 100 S: The viscosity increase rate (%) after storage is less than 10%. A: The viscosity increase rate (%) after storage is 10% or more and less than 50%. B: The viscosity increase rate (%) after storage is 50% or more and less than 100%. C: The viscosity increase rate (%) after storage is 100% or more and less than 200%. D: The viscosity increase rate (%) after storage is 200% or more.

[0084] <Finished product> The appearance of the test plates obtained in the conductivity evaluation test described later was observed, and the finish quality was evaluated visually. S: Has an extremely uniform appearance. A: It has a uniform appearance. B: Although there are some areas that appear slightly uneven, it has a nearly uniform appearance. C: Unevenness is visible, indicating a slightly poor condition. D: The appearance is clearly uneven and defective.

[0085] <Conductive> Two strips of aluminum foil tape (Sumitomo 3M, No. 425) were attached parallel to each other at a 3cm interval on a polypropylene board (10cm x 15cm x 3mm). Next, the resulting conductive pigment paste was applied between the aluminum foil tapes using an applicator to a length of 5cm and a dry film thickness of 15μm. After being left at room temperature for 2 minutes, it was heated and dried at 80°C for 10 minutes to create a dry coating film with a width of 3cm, a length of 5cm, and a film thickness of 15μm. The resistivity of the dried coating applied between aluminum foil tapes was measured using a measuring instrument (Yokogawa Electric Co., Ltd., product name: Digital Multimeter MODEL73401) at 20°C and 65% relative humidity, and the conductivity was evaluated according to the following criteria. S: The resistivity is less than 0.005 Ωm, indicating the best conductivity. A: The resistivity is 0.005 Ωm or higher and less than 0.0065 Ωm, indicating very good conductivity. B: The resistivity is 0.0065 Ωm or higher and less than 0.008 Ωm, indicating good conductivity. C: The resistivity is 0.008 Ωm or higher and less than 0.01 Ωm, indicating slightly poor conductivity. D: The resistivity is 0.01 Ωm or higher, and the conductivity is very poor.

[0086] [Examples 39-76] <Manufacturing of coating materials and coating films> To 100 parts of the conductive pigment paste (X-1 to X-38) obtained in Examples 1 to 38, add 50 parts of N-methyl-2-pyrrolidone as a solvent and Na as composite metal particles (G1). 2 / 3 Ni 1 / 3 Mn 2 / 3 Twenty parts of O2 (average particle size: 5 μm) were added, and the mixture was stirred using a disperser for 60 minutes to obtain coating materials Y-1 to Y-38, which will be used in Examples 39 to 76. Next, a cold-rolled steel sheet (150mm (length) x 70mm (width) x 0.8mm (thickness)) that had been chemically treated with a zinc phosphate treatment agent (manufactured by Nippon Parkerizing Co., Ltd., product name Palbond #3020) was used as the substrate, and the above coating materials Y-1 to Y-38 were applied with an applicator to a dry film thickness of 50 μm, and dried at a temperature of 150°C for 40 minutes to obtain the coating film. All of the resulting coating films had a residual solvent content of less than 1%, and were coating films with good finish properties.

[0087] [Examples 77-92] <Manufacturing of coating materials and coating films> The ingredients in Table 4 below were added in order from top to bottom while stirring with a disperser, and finally stirred for 60 minutes to obtain coating materials Z-1 to Z-16, which correspond to Examples 77 to 92. Next, using aluminum foil (150 mm (length) x 70 mm (width)) as the substrate, the above coating materials Z-1 to Z-16 were applied with an applicator to a dry film thickness of 50 μm, and the mixture was dried at 150°C for 40 minutes to obtain the coated film. All of the resulting coating films had a residual solvent content of less than 1%, and were coating films with good finish properties. Tables 5 and 6 below show the evaluation results of storage stability for coating materials Z-1 to Z-16.

[0088] [Table 5]

[0089] [Table 6]

[0090] <Conductive pigment paste> Conductive pigment pastes obtained in Examples 1, 17, 26, 33, and 34 (X-1, X-17, X-26, X-33, X-34) <Solvent (C)> NMP:N-methyl-2-pyrrolidone <High polar low molecular weight component (E)> Glu: Glutamic acid Be-A: Benzylamine ME-A: Methylethanolamine TP-A: Triphenylamine <Metal-containing particles (G)> Composite metal particles (G1):Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 (average particle size: 5μm)

[0091] <Storage Stability (Coating Materials)> The obtained coating materials Z-1 to Z-16 were stored at 30°C for two weeks, and the initial viscosity and viscosity after storage were compared. Viscosity was measured using a cone and plate viscometer (HAAKE, product name Mars2, 35 mm diameter, 2° inclined cone and plate) at a shear rate of 1.0 s. -1 The viscosity was measured, the viscosity increase rate was determined using the following formula, and the storage stability was evaluated according to the following criteria. Viscosity increase rate (%) = Viscosity after storage (mPa·s) / Initial viscosity (mPa·s) × 100 - 100 A: The viscosity increase rate (%) after storage is less than 50%. B: The viscosity increase rate (%) after storage is 50% or more and less than 100%. C: The viscosity increase rate (%) after storage is 100% or more and less than 200%. D: The viscosity increase rate (%) after storage is 200% or more.

Claims

1. A conductive pigment paste comprising a pigment dispersion resin (A), a conductive pigment (B), a solvent (C), a fluororesin (D), and a highly polar, low molecular weight component (E), The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups, and the concentration of the polar functional group of the pigment dispersion resin (A) is 10 to 23 mmol / g. The conductive pigment (B) has an average primary particle size of 10-80 nm and a BET specific surface area of ​​250 m². ２ / g or less, The solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) are related by |δA - δC| < 2.

0. The aforementioned highly polar, low molecular weight component (E) is an amine compound with a boiling point of 400°C or lower. Shear rate 0.1 s －１ The viscosity is less than 5,000 mPa·s. Conductive pigment paste.

2. The conductive pigment paste according to claim 1, wherein the solid content of the pigment dispersion resin (A) is 0.1 to 20% by mass, based on the total amount of solids in the conductive pigment paste.

3. The conductive pigment paste according to claim 1 or 2, wherein the content of conductive pigment (B) is 5 to 99.9% by mass, based on the total solid content of the conductive pigment paste.

4. A conductive pigment paste according to any one of claims 1 to 3, wherein the solubility parameter δA of the pigment dispersion resin (A) is 9.3 or higher, and the solubility parameter δC of the solvent (C) is 10.4 to 15.

0.

5. A conductive pigment paste according to any one of claims 1 to 4, wherein the conductive pigment paste is diluted in a solvent, and the frequency distribution curve obtained by volume-based particle size distribution measurement by laser diffraction scattering has at least two peaks, with at least one peak top in the particle size range of 150 to 550 nm and at least one peak top in the particle size range of 600 to 3,000 nm, and the peak area ratio in the particle size range (total peak area in the particle size range of 150 to 550 nm / total peak area in the particle size range of 600 to 3,000 nm) is 0.2 to 3.

6. A conductive pigment paste according to any one of claims 1 to 5, wherein the conductive pigment paste is diluted with a solvent, and the average particle size (D50) obtained by volume-based particle size distribution measurement by laser diffraction scattering is 860 to 1,400 nm.

7. Shear rate of conductive pigment paste: 0.1 s －１ Viscosity X and shear rate 1,000 s －１ A conductive pigment paste according to any one of claims 1 to 6, wherein the viscosity Y satisfies the relationship 500 mPa·s < X < 5,000 mPa·s and X / Y > 1.

0.

8. The conductive pigment paste according to any one of claims 1 to 7, wherein the conductive pigment (B) is at least one conductive carbon selected from the group consisting of acetylene black, Ketjen black, furnace black, thermal black, graphene, and graphite.

9. A conductive pigment paste according to any one of claims 1 to 8, wherein the highly polar, low molecular weight component (E) contains at least one amine compound (E1).

10. A conductive pigment paste according to any one of claims 1 to 9, wherein the fluororesin (D) is a resin having a weight-average molecular weight of 100,000 or more and a solubility parameter δD of less than 9.

3.

11. A conductive pigment paste comprising a conductive pigment paste according to any one of claims 1 to 10 and carbon nanotubes (F), wherein the solid content ratio of conductive pigment (B) to carbon nanotubes in the conductive pigment paste is 1 / 99 to 99 / 1.

12. A conductive pigment paste containing a pigment dispersion resin (A), acetylene black (B-2), carbon nanotubes (F), a solvent (C), a fluororesin (D), and a highly polar, low molecular weight component (E), The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups, and the concentration of the polar functional group of the pigment dispersion resin (A) is 10 to 23 mmol / g. Acetylene black (B-2) has an average primary particle size of 10-80 nm and a BET specific surface area of ​​250 m². ２ / g or less, The solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) are related by |δA - δC| < 2.

0. The aforementioned highly polar, low molecular weight component (E) is an amine compound with a boiling point of 400°C or lower. Shear rate 0.1 s －１ The viscosity is less than 5,000 mPa·s. Conductive pigment paste.

13. A method for dispersing a conductive pigment paste, wherein the conductive pigment paste is dispersed substantially without the use of a mediator when manufacturing the conductive pigment paste according to any one of claims 1 to 11.

14. A coating material comprising a conductive pigment paste according to any one of claims 1 to 12 and metal-containing particles (G) having at least one metal element.

15. A coating material comprising a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), a solvent (C), a fluororesin (D), and a highly polar, low molecular weight component (E), and metal-containing particles (G) having at least one metal element, The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of amide groups, imide groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, silanol groups, amino groups, and cyano groups, and the concentration of the polar functional group of the pigment dispersion resin (A) is 10 to 23 mmol / g. The conductive pigment (B) has an average primary particle size of 10-80 nm and a BET specific surface area of ​​250 m². ２ / g or less, The solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) are related by |δA - δC| < 2.

0. Shear rate 0.1 s －１ The viscosity is less than 5,000 mPa·s. The aforementioned highly polar, low molecular weight component (E) is an amine compound with a boiling point of 400°C or lower. The highly polar, low molecular weight component (E) is contained in an amount of 3% by mass or more, based on 100% by mass of the solid content of the conductive pigment (B). Coating material.

16. A method for producing a coating material, comprising adding metal-containing particles (G) having at least one metal element to a conductive pigment paste according to any one of claims 1 to 12.

17. A coating film obtained by applying the coating material described in claim 14 or 15.

18. A coated material obtained by coating both sides of a plate-shaped substrate with the coating material described in claim 14 or 15.

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