JP2022176927A - Method for producing conductive pigment paste - Google Patents

Abstract

To provide a method for producing a conductive pigment paste and a composite paste having excellent pigment dispersibility and storage stability even at a high pigment concentration and to provide a method for producing an electrode layer for a battery having excellent battery performance.SOLUTION: There is provided a method for producing a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B) and a solvent (C), wherein the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphate group, a silanol group and an amino group and a polar functional group concentration of 9 to 23 mmol/g, the conductive pigment (B) contains carbon nanotubes (B-1) and/or conductive carbons (B-2) having an average primary particle diameter of 10 to 80 nm, in which a powder raw material (P) containing the conductive pigment (B) is added in a liquid raw material (L) obtained by mixing the pigment dispersion resin (A), the solvent (C) and optionally other components, followed by mixing and dispersing by a media-less dispersion machine.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a conductive pigment paste and a mixture paste that are excellent in pigment dispersibility and storage stability even at a high pigment concentration, and a method for producing a battery electrode layer having excellent battery performance.

Conventionally, a paste-like pigment dispersion in which a pigment is dispersed in a mixture of a pigment dispersion resin and a solvent is used as a paint, a battery electrode, a coating material, a coating material, an electromagnetic wave shield, a display panel, a touch screen panel, a colored film. , colored sheets, decorative materials, protective materials, magnet modifiers, printing inks, device members, electronic device members, printed wiring boards, solar cells, functional rubber members, resin molded films, etc. . Furthermore, these materials contain conductive pigments, conductive polymers, and the like in order to impart functions such as electrostatic coating properties, conductivity, electromagnetic wave shielding properties, and antistatic properties.

In these fields, there is an increasing demand for improvements in pigment dispersibility, storage stability, coatability, electrical conductivity, and finishing properties. Pigment dispersing resins and pigment pastes that have excellent pigment dispersion stability enough to prevent reaggregation of pigment particles therein are being developed.

In designing the pigment paste, it is necessary to ensure that the pigment dispersion resin does not adversely affect the conductive performance of the final product itself, such as a coating film, or to reduce the amount of solvent and pigment dispersion resin used, and to reduce the amount of solvent and pigment dispersion resin used during drying. From the viewpoint of reducing energy, it is important to prepare a highly concentrated and uniformly dispersed pigment paste with a small amount of pigment dispersing resin.

For example, in Patent Document 1, a solvent containing fibrous carbon is dispersed by a media (hereinafter sometimes referred to as "media") type disperser to obtain a slurry, and the slurry is kneaded with an electrode active material. Disclosed is a method for producing a slurry for electrodes of a lithium secondary battery, characterized in that a slurry to be applied to a current collector is thus obtained. However, pastes with high pigment concentrations and/or high viscosities may not be uniformly dispersed.

JP 2014-182892 A

An object of the present invention is to provide a method for producing a conductive pigment paste that is excellent in pigment dispersibility and storage stability even in a paste with a high pigment concentration and / or high viscosity, An object of the present invention is to provide a method for producing a coating film which is excellent in

As a result of intensive studies to solve the above problems, the present inventors have found a method for producing a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), and a solvent (C). The pigment dispersing resin (A) contains at least one polar functional group selected from the group consisting of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group. and the pigment dispersion resin (A) has a polar functional group concentration of 9 to 23 mmol / g, and the conductive pigment (B) contains carbon nanotubes (B-1) and / or an average primary particle diameter of 10 to 80 nm. A conductive pigment (B ), and mixing and dispersing with a medialess dispersing machine. Arrived.

That is, the present invention provides the following conductive pigment paste, mixture paste, and method for producing a battery electrode layer.

Section 1.
A method for producing a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), and a solvent (C),
The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group. and the pigment dispersion resin (A) has a polar functional group concentration of 9 to 23 mmol/g,
The conductive pigment (B) contains carbon nanotubes (B-1) and/or conductive carbon (B-2) having an average primary particle diameter of 10 to 80 nm,
Powder raw material (P) containing conductive pigment (B) is added to liquid raw material (L) obtained by mixing pigment dispersion resin (A), solvent (C), and optionally other components. and mix and disperse with a medialess disperser,
A method for producing a conductive pigment paste.
Section 2.
Item 2. The method for producing a conductive pigment paste according to Item 1, wherein the medialess dispersing machine has a rotor and a stator in a casing, and is a dispersing machine that performs mixing, dispersion, and pumping by rotating the rotor. .
Item 3.
Item 3. The method for producing a conductive pigment paste according to item 2, wherein the powder raw material (P) is sucked in using negative pressure generated when a rotor rotates.
Section 4.
After mixing and dispersing by the medialess disperser, at least one disperser selected from the group consisting of a paint shaker, a bead mill, a ball mill, a pebble ball mill, a homogenizer, an ultrasonic disperser, a kneader, an extruder, and a planetary kneader. Item 4. A method for producing a conductive pigment paste according to any one of items 1 to 3, characterized in that additional dispersion is performed by a machine.
Item 5.
Item 5. A method for producing a conductive pigment paste according to item 4, wherein the dispersing machine used for the additional dispersion is an annular bead mill.
Item 6.
Item 6. The method for producing a conductive pigment paste according to item 5, wherein the annular bead mill is a biaxially driven annular bead mill.
Item 7.
Item 5. A method for producing a conductive pigment paste according to Item 4, wherein the dispersing machine used for the additional dispersion is an ultra-high-speed homogenizer or a high-pressure homogenizer.
Item 8.
Item 8. The method for producing a conductive pigment paste according to any one of Items 1 to 7, wherein the pigment dispersion resin (A) contains ionic polyvinyl alcohol.
Item 9.
Item 9. A method for producing a conductive pigment paste according to Item 8, wherein the degree of saponification of the ionic polyvinyl alcohol is 85 mol% or more and less than 100 mol%.
Item 10.
The conductive pigment according to any one of Items 1 to 9, wherein the solid content of the pigment dispersion resin (A) is 0.1 to 50% by mass based on the total solid content of the conductive pigment paste. A method for producing a paste.
Item 11.
The conductive pigment (B) contains carbon nanotubes (B-1), and the solid content of the pigment dispersion resin (A) is 5 to 50% by mass based on the total solid content of the conductive pigment paste. , a method for producing a conductive pigment paste according to any one of items 1 to 10.
Item 12.
The conductive pigment (B) does not contain carbon nanotubes (B-1), and the solid content of the pigment dispersion resin (A) is 0.1 to 20 mass based on the total solid content of the conductive pigment paste. %, the method for producing a conductive pigment paste according to any one of items 1 to 10.
Item 13.
The content of the conductive pigment (B) is 1 to 90% by mass based on the total amount of the conductive pigment paste, and 10 to 99.9% by mass based on the total solid content of the conductive pigment paste. A method for producing a conductive pigment paste according to any one of Items 1 to 12.
Item 14.
The conductive pigment (B) contains carbon nanotubes (B-1), the content of the carbon nanotubes (B-1) is 1 to 20% by mass based on the total amount of the conductive pigment paste, and the conductive 14. The method for producing a conductive pigment paste according to any one of Items 1 to 11 and 13, which is 10 to 99% by mass based on the total solid content of the conductive pigment paste.
Item 15.
The conductive pigment (B) contains conductive carbon (B-2) having an average primary particle diameter of 10 to 80 nm, and the content of the conductive carbon (B-2) is based on the total amount of the conductive pigment paste. The conductive pigment paste according to any one of Items 1 to 14, which is 5 to 90% by mass and 40 to 99.9% by mass based on the total solid content of the conductive pigment paste. How to manufacture.
Item 16.
The method for producing a conductive pigment paste according to any one of Items 1 to 11 and 13 to 15, wherein the carbon nanotubes (B-1) contain multi-walled carbon nanotubes.
Item 17.
The conductive pigment (B) contains conductive carbon (B-2) having an average primary particle size of 10 to 80 nm, and the conductive carbon (B-2) is acetylene black, ketjen black, furnace black, thermal black. Item 17. The method for producing a conductive pigment paste according to any one of items 1 to 16, wherein the paste is at least one selected from the group consisting of , graphene and graphite.
Item 18.
18. Any one of items 1 to 17, 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 to 15.0. A method of making the described conductive pigment paste.
Item 19.
Item 19. Any one of items 1 to 18, wherein 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|<2.1. A method for producing a conductive pigment paste.
Item 20.
20. Producing the conductive pigment paste according to any one of Items 1 to 19, wherein the liquid raw material (L) is produced by dissolving the pigment dispersion resin (A) in the solvent (C) heated to 50 ° C. or higher. how to.
Item 21.
Item 21. A method for producing a conductive pigment paste, wherein the conductive pigment paste obtained by the method according to any one of Items 1 to 20 contains substantially no water.
Item 22.
Item 22. A method for producing a conductive pigment paste, wherein the conductive pigment paste obtained by the method according to any one of Items 1 to 21 does not substantially contain metal.
Item 23.
Item 23. A method for producing a mixture paste, comprising adding at least one electrode active material to the conductive pigment paste produced by the method according to any one of Items 1 to 22.
Item 24.
Item 24. A method for producing a battery electrode layer obtained by coating a current collector with the mixture paste obtained by the method according to Item 23.

The method for producing a conductive pigment paste of the present invention is excellent in pigment dispersibility and storage stability even at high pigment concentrations and/or high viscosities, and the viscosity of the paste is sufficiently increased with a relatively small blending amount of the pigment dispersing resin. can be lowered. In addition, the coating film is excellent in finishing properties, electrical conductivity, battery performance, and the like.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below.

It should be understood that the present invention is not limited to the following embodiments, but includes various modifications implemented without departing from the gist of the present invention.

In the present invention, first, a conductive pigment paste having a conductive pigment (B) in a moderately dispersed state is prepared, and various components are added to the conductive pigment paste in order to obtain a coating film that satisfies various properties. It manufactures a mixture paste.

In the present invention, a paste prepared by further blending at least one electrode active material and optionally other various components for coating a conductive pigment paste is referred to as a "mixture paste". A product obtained by applying the mixture paste to an object to be coated and drying it is called a “coating film”. When the coating film is used for a battery electrode, it can also be called an "electrode layer".

A method for producing a conductive pigment paste of the present invention is a method for producing a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), and a solvent (C), wherein the pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group; and The pigment dispersion resin (A) has a polar functional group concentration of 9 to 23 mmol/g, and the conductive pigment (B) is a carbon nanotube (B-1) and/or a conductive carbon having an average primary particle diameter of 10 to 80 nm ( B-2), and the conductive pigment (B) is contained in the liquid raw material (L) obtained by mixing the pigment dispersion resin (A), the solvent (C), and optionally other components. The powder raw material (P) is charged, and mixed and dispersed using a medialess disperser.

In the present invention, a powder raw material containing a conductive pigment (B) in a liquid raw material (L) obtained by mixing a pigment dispersion resin (A), a solvent (C), and optionally other components ( P) is dispersed in a mixture containing the pigment dispersion resin (A), the conductive pigment (B) and the solvent (C), and the conductive pigment (B) is added to the pigment dispersion resin (A) and It means dispersing in the solvent (C). In addition, the lumps of the conductive pigment (B) in the mixture containing the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) are crushed to form smaller lumps of the conductive pigment (B) in the mixture. Also included in the term "dispersing a paste" is dispersing in a paste.

<Pigment dispersion resin (A)>
The pigment dispersion resin (A) that can be used as a component of the conductive pigment paste consists of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group. It contains at least one polar functional group selected from the group. The polar functional group concentration of the resin (A) is usually 9 to 23 mmol/g, preferably 10 to 22.5 mmol/g, from the viewpoint of dispersibility, storage stability, and compatibility with a solvent. and more preferably 11 to 22 mmol/g.

Further, the solubility parameter δA of the pigment dispersion resin (A) is preferably 9.3 (cal/cm ³ ) ^1/2 or more from the viewpoint of dispersibility, storage stability, and compatibility with a solvent. 0 to 13.0 (cal/cm ³ ) ^1/2 is more preferable, and 11.0 to 12.5 (cal/cm ³ ) ^1/2 is even more preferable.

Here, the solubility parameter is generally called an SP value (solubility parameter), and is a scale indicating the degree of hydrophilicity or hydrophobicity (polarity) of a solvent or resin. In addition, it is an important measure for judging the solubility and compatibility between solvents and resins, and between resins. Solubility and compatibility are generally improved.

The solubility parameter of the resin is numerically quantified based on a turbidity measurement method known to those skilled in the art. 2359, 1968).

When two or more pigment dispersion resins (A) are used, the "solubility parameter δA of the pigment dispersion resin (A)" is the sum of the solubility parameter values of each resin multiplied by the mass fraction.

Specific examples of resin types include acrylic resin, polyester resin, epoxy resin, polyether resin, alkyd resin, urethane resin, polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, polyvinyl acetate, silicone resin, and polycarbonate resin. , silicate resins, chlorine-based resins, fluorine-based resins, composite resins thereof, and the like. These resins can be used singly or in combination of two or more.

Among them, 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, as the pigment dispersion resin (A) and a vinyl (co)polymer (A-1) obtained by polymerizing or copolymerizing a monomer containing a polymerizable unsaturated group-containing monomer represented by the following formula (1). The "(co)polymer" of the present invention includes both a polymer obtained by polymerizing one type of monomer and a copolymer obtained by copolymerizing two or more types of monomers.
C(-R) ₂ =C(-R) ₂ Formula (1)
[In formula (1) above, each R may be the same or different and is a hydrogen atom or an organic group. ]

The vinyl (co)polymer (A-1) has a structural unit represented by “—CH ₂ —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 includes an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group. It is at least one polar functional group selected from the group consisting of:

Examples of the vinyl (co)polymer (A-1) include a hydroxyl group-containing vinyl (co)polymer, a carboxyl group-containing vinyl (co)polymer, a pyrrolidone group-containing vinyl (co)polymer, an amide group-containing vinyl Examples include (co)polymers, sulfonic acid group-containing vinyl (co)polymers, phosphoric acid group-containing vinyl (co)polymers, amino group-containing vinyl (co)polymers, and the like. These (co)polymers can be used alone or in combination of two or more.

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). Examples include copolymers, copolymers of hydroxyethyl (meth)acrylate and other polymerizable unsaturated monomers, and the like. The vinyl alcohol unit in the (co)polymer may be obtained by (co)polymerizing a fatty acid vinyl unit and then hydrolyzing it.

Carboxyl group-containing vinyl (co)polymers include, for example, polymers of (meth)acrylic acid, copolymers of poly(meth)acrylic acid and other polymerizable unsaturated monomers, and the like.

Examples of pyrrolidone group-containing vinyl (co)polymers include polyvinylpyrrolidone, N-vinyl-2-pyrrolidone-ethylene copolymer, N-vinyl-2-pyrrolidone-vinyl acetate copolymer and the like.

Amide group-containing vinyl (co)polymers include, for example, polymers of (meth)acrylamide, copolymers of (meth)acrylamide and other polymerizable unsaturated monomers, and the like.

Examples of sulfonic acid group-containing vinyl (co)polymers include polymers of allylsulfonic acid or styrenesulfonic acid, copolymers of allylsulfonic acid and/or styrenesulfonic acid with other polymerizable unsaturated monomers, and the like. is mentioned.

Phosphate group-containing vinyl (co)polymers include, for example, polymers of (meth)acryloyloxyalkyl acid phosphate, copolymers of (meth)acryloyloxyalkyl acid phosphate and other polymerizable unsaturated monomers, and the like. is mentioned.

Examples of amino group-containing vinyl (co)polymers include polyvinylamine, polyallylamine, polymers of dimethylaminoethyl (meth)acrylate, and copolymers of dimethylaminoethyl (meth)acrylate and other polymerizable unsaturated monomers. A polymer etc. are mentioned.

In these embodiments, the "other polymerizable unsaturated monomer" is not particularly limited, but includes, for example, those listed as "copolymerizable polymerizable unsaturated group-containing monomer" described later, and acetic acid. Vinyl and the like are preferred.

Among these vinyl (co)polymers (A-1), from the viewpoint of improving dispersibility and reducing the surface resistivity of the conductive coating film, a hydroxyl group-containing polyvinyl (co)polymer, a carboxyl group Polyvinyl (co)polymers containing pyrrolidone groups and polyvinyl (co)polymers containing pyrrolidone groups are preferred, polyvinyl (co)polymers containing hydroxyl groups are more preferred, and polyvinyl alcohol (co)polymers are even more preferred.

From the viewpoint of dispersibility, the polyvinyl alcohol (co)polymer preferably has a saponification degree of 85 mol% or more and less than 100 mol%, more preferably 90 mol% or more and less than 100 mol%, and 95 mol% or more and less than 100 mol%. is particularly preferred.

Among the polyvinyl alcohol (co)polymers, ionic polyvinyl alcohol having an ionic functional group is particularly preferable from the viewpoint of dispersibility. Examples of ionic functional groups include carboxyl groups, sulfonic acid groups, phosphoric acid groups, and amino groups. Ionic polyvinyl alcohol can be produced by the following method.
(1) A method of copolymerizing a compound containing an ionic functional group and a polymerizable unsaturated group with a fatty acid vinyl ester such as vinyl acetate and further saponifying the resulting polymer.
(2) A method of Michael addition of a compound containing an ionic functional group and a polymerizable unsaturated group to polyvinyl alcohol.
(3) A method of heating polyvinyl alcohol with an aqueous solution (acetic acid aqueous solution, sulfuric acid aqueous solution, phosphoric acid aqueous solution, ammonia aqueous solution, etc.) corresponding to the functional group to be modified.
(4) A method of acetalizing polyvinyl alcohol with an aldehyde compound containing an ionic functional group.
(5) A method of polymerizing polyvinyl alcohol in the presence of an alcohol having an ionic functional group, an aldehyde, and a compound having a functional group such as thiol as a chain transfer agent.

Any production method can be suitably used, but the method (1) is particularly preferred.

In these embodiments, the compound containing an ionic functional group and a polymerizable unsaturated group includes, for example, a compound containing a carboxyl group and a polymerizable unsaturated group (e.g., acrylic acid, methacrylic acid, etc.), sulfonic acid a compound containing a group and a polymerizable unsaturated group (e.g., allylsulfonic acid, styrenesulfonic acid, etc.), a compound containing a phosphoric acid group and a polymerizable unsaturated group (e.g., (meth)acryloyloxyalkyl acid phosphate, etc.) , compounds containing an amino group and a polymerizable unsaturated group (eg, vinylamine, allylamine, dimethylaminoethyl (meth)acrylate, etc.).

Incidentally, the vinyl (co)polymer (A-1) may optionally include a copolymerizable polymerizable non-polymerizable polymer in addition to the structural unit represented by the above “—CH ₂ —CH(—X)—”. It may contain a structural unit derived from a saturated group-containing monomer. Examples of copolymerizable polymerizable unsaturated group-containing monomers include vinyl formate, vinyl acetate, vinyl propionate, isopropenyl acetate, vinyl valerate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl stearate, Carboxylic acid vinyl ester monomers such as vinyl benzoate, vinyl versatic acid and vinyl pivalate; olefins such as ethylene, propylene and butylene; aromatic vinyl compounds such as styrene and α-methylstyrene; methacrylic acid and fumaric acid , maleic acid, itaconic acid, monoethyl fumarate, maleic anhydride, and ethylenically unsaturated carboxylic acid monomers such as itaconic anhydride; methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid n -Butyl, 2-ethylhexyl (meth)acrylate, dimethyl fumarate, dimethyl maleate, diethyl maleate, diisopropyl itaconate and other ethylenically unsaturated carboxylic acid alkyl ester monomers; methyl vinyl ether, n-propyl vinyl ether, isobutyl vinyl ether monomers such as vinyl ether and dodecyl vinyl ether; ethylenically unsaturated nitrile monomers such as (meth)acrylonitrile; halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride, or vinylidene monomers Allyl compounds such as allyl acetate and allyl chloride; Sulfonic acid group-containing monomers such as ethylenesulfonic acid, (meth)allylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid; 3-(meth)acrylamide quaternary ammonium group-containing monomers such as propyltrimethylammonium chloride; vinyltrimethoxysilane, N-vinylformamide, methacrylamide and the like. These monomers can be used individually or in combination of 2 or more types.

The vinyl (co)polymer (A-1) can be produced by a polymerization method known per se. For example, solution polymerization is preferably used, but the method is not limited to bulk polymerization. Alternatively, emulsion polymerization, suspension polymerization, or the like may be used. When solution polymerization is carried out, it may be continuous polymerization or batch polymerization.

The polymerization initiator used in the solution polymerization is not particularly limited, but specific examples include azobisisobutyronitrile, azobis-2,4-dimethylpareronitrile, azobis(4-methoxy-2 ,4-dimethylpareronitrile) and other azo compounds; acetyl peroxide, benzoyl peroxide, lauroyl peroxide, acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate and other peroxides Peroxydicarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate; t-butyl peroxyneodecanate, α-cumyl peroxyneodecanate , t-butylperoxyneodecanate and other perester compounds; and known radical polymerization initiators such as azobisdimethylvaleronitrile and azobismethoxyvaleronitrile.

Although the polymerization reaction temperature is not particularly limited, it can usually be set in the range of about 30 to 200°C.

Also, the weight average molecular weight is preferably from 1,000 to 200,000, more preferably from 2,000 to 100,000, and even more preferably from 7,000 to 30,000.

The vinyl (co)polymer (A-1) can be made into a solid or a resin solution in which an arbitrary solvent is substituted by removing the solvent and/or replacing the solvent after completion of the synthesis.

As a method for removing the solvent, heating may be performed at normal pressure, or the solvent may be removed under reduced pressure. As a method for solvent replacement, the replacement solvent may be added at any stage before, during, or after solvent removal.

From the viewpoint of pigment dispersibility and storage stability, the solid content of the pigment dispersion resin (A) is preferably 0.1% by mass or more, and preferably 0.3% by mass, based on the total solid content of the conductive pigment paste. % or more, more preferably 0.5 mass % or more, more preferably 1 mass % or more, even more preferably 5 mass % or more, and particularly preferably 10 mass % or more. The upper limit of the solid content of the pigment dispersion resin (A) is preferably 50% by mass or less, more preferably 40% by mass or less, and 35% by mass or less, based on the total solid content of the conductive pigment paste. More preferably, 30% by mass or less is particularly preferable. Further, the range of the solid content of the pigment dispersion resin (A) is preferably 0.1 to 50% by mass, more preferably 0.3 to 45% by mass, based on the total solid content of the conductive pigment paste. , 0.5 to 40% by weight are particularly preferred.

When the conductive pigment paste produced by the method of the present invention contains carbon nanotubes (B-1) as the conductive pigment (B), the solid content of the pigment dispersion resin (A) is From the viewpoint of storage stability, it is preferably 5 to 50% by mass, more preferably 8 to 40% by mass, and particularly preferably 10 to 30% by mass, based on the total solid content of the conductive pigment paste.

When the conductive pigment paste produced by the method of the present invention does not contain the carbon nanotube (B-1) as the conductive pigment (B), the solid content of the pigment dispersion resin (A) is From the viewpoint of storage stability, it is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and particularly preferably 1 to 10% by mass, based on the total solid content of the conductive pigment paste.

<Conductive Pigment (B)>
The conductive pigment (B) used in the present invention contains carbon nanotubes (B-1) and/or conductive carbon (B-2) having an average primary particle size of 10 to 80 nm.

Single-walled carbon nanotubes or multi-walled carbon nanotubes can be used alone or in combination as the carbon nanotubes (B-1). In particular, it is preferable to use multi-walled carbon nanotubes in terms of viscosity, conductivity and cost.

The outer diameter of the carbon nanotube (B-1) 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 (B-1) is preferably 1 to 100 μm, more preferably 5 to 80 μm, particularly preferably 10 to 60 μm.

The specific surface area of the carbon nanotube (B-1) is preferably in the range of 1 to 1000 m ² /g, more preferably in the range of 10 to 500 m ² /g, from the viewpoint of viscosity and conductivity. More preferred.

The conductive carbon (B-2) having an average primary particle size of 10 to 80 nm is spherical, ellipsoidal, plate-like, scale-like, or amorphous conductive carbon other than the carbon nanotube (B-1). and the average primary particle size is usually 10 to 80 nm, preferably 15 to 60 nm, more preferably 20 to 50 nm.

Here, the average primary particle size of the present invention is obtained by observing the pigment with an electron microscope, obtaining the projected area of each of 100 particles, and obtaining the diameter when a circle equal to the area is assumed. It means the average diameter of primary particles obtained by simply averaging the diameters of the particles. In addition, when the pigment is in an aggregated state, the primary particles constituting the aggregated particles are used for the calculation.

Specific examples of the conductive carbon (B-2) include acetylene black, ketjen black, furnace black, thermal black, graphene, and graphite. These conductive carbons can also be used in combination of two or more.

The specific surface area of the conductive carbon (B-2) is preferably in the range of 1 to 500 m ² /g, more preferably in the range of 30 to 150 m ² /g, in view of the relationship between viscosity and conductivity. is more preferred.

The above-mentioned conductive carbon (B-2) is preferably basic in terms of pigment dispersibility. is more preferred, and 8.5 to 11.0 is even more preferred.

In addition, from the viewpoint of conductivity, the conductive carbon (B-2) preferably has a state in which the primary particles form a chain structure (structure), and the structure index is in the range of 1.5 to 4.0. more preferably within the range of 1.7 to 3.2.

The structure itself can be observed relatively easily in an image taken with an electron microscope, but the structure index is a numerical value that quantifies the degree of structure. The structure index can generally be defined as a value obtained by dividing the DBP oil absorption (ml/100g) by the specific surface area (m ² /g). If the structure index is less than 1.5, the structure is not developed and sufficient conductivity cannot be obtained, and if it exceeds 4.0, the particle size is large relative to the DBP oil absorption. There is a risk that the conductive path will be reduced in the future, and it will not exhibit sufficient conductivity, or the viscosity of the composite paste will be high.

The conductive pigment (B) may contain a conductive pigment other than carbon nanotubes (B-1) and/or conductive carbon (B-2) having an average primary particle size of 10 to 80 nm. There is no particular limitation as long as it can impart electrical conductivity to the coating film to be formed, and examples include pigments in the form of particles, flakes, and fibers (including whiskers). Specific examples include powders of metals such as silver, nickel, copper, graphite, and aluminum. Further, antimony-doped tin oxide, phosphorous-doped tin oxide, and tin oxide/antimony are added to the surface. Acicular coated titanium oxide, antimony oxide, zinc antimonate, indium tin oxide, carbon or graphite whisker surface coated with tin oxide, etc.; flaky mica surface tin oxide, antimony-doped tin oxide, tin-doped A pigment coated with at least one conductive metal oxide selected from the group consisting of indium oxide (ITO), fluorine-doped tin oxide (FTO), phosphorus-doped tin oxide and nickel oxide; tin oxide and phosphorus on the surface of titanium dioxide particles; and conductive pigments, and the above-mentioned conductive pigments may be used in combination of two or more.

The content of the conductive pigment (B) is preferably 1 to 90% by mass, more preferably 3 to 70% by mass, based on the total amount of the conductive pigment paste, from the viewpoint of conductivity and pigment dispersibility. ~50% by weight is particularly preferred. Also, based on the total solid content of the conductive pigment paste, it is preferably 10 to 99.9% by mass, more preferably 30 to 99% by mass, and particularly preferably 50 to 98% by mass.

When the conductive pigment (B) contains the carbon nanotube (B-1), the content of the carbon nanotube (B-1) is based on the total amount of the conductive pigment paste from the viewpoint of conductivity and pigment dispersibility. , preferably 1 to 20% by mass, more preferably 2 to 18% by mass, and particularly preferably 3 to 15% by mass. Also, based on the total solid content of the conductive pigment paste, it is preferably 10 to 99% by mass, more preferably 30 to 95% by mass, and particularly preferably 50 to 90% by mass.

When the conductive pigment (B) contains conductive carbon (B-2) having an average primary particle size of 10 to 80 nm, the content of the conductive carbon (B-2) is determined based on the conductivity and pigment dispersibility. From a viewpoint, based on the total amount of the conductive pigment paste, 5 to 90% by mass is preferable, 10 to 80% by mass is more preferable, and 20 to 70% by mass is particularly preferable. Also, based on the total solid content of the conductive pigment paste, it is preferably 40 to 99.9% by mass, more preferably 50 to 99% by mass, and particularly preferably 60 to 98% by mass.

When the conductive pigment (B) contains both carbon nanotubes (B-1) and conductive carbon (B-2) having an average primary particle diameter of 10 to 80 nm, the weight ratio (B-1)/( B-2) is preferably in the range of 0.1/99.9 to 99.9/0.1, more preferably in the range of 1/99 to 90/10.

<Solvent (C)>
As the solvent (C) that can be used in the conductive pigment paste, conventionally known solvents can be used 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; methyl isobutyl ketone and the like. Ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol; ethyl acetate, n-butyl acetate, isobutyl acetate , Ester-based solvents such as ethylene glycol monomethyl ether acetate, butyl carbitol acetate; Ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone; Alcohols such as ethanol, isopropanol, n-butanol, sec-butanol, isobutanol, etc. System solvent; Equamid (trade name, manufactured by Idemitsu Kosan Co., Ltd., amide solvent), N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methylacetamide, N-methylpropioamide, Examples include amide solvents such as N-methyl-2-pyrrolidone. These solvents can be used singly or in combination of two or more.

Among them, the solvent (C) that can be used in the conductive pigment paste includes a hydroxyl group, a carboxyl group, an amide group, and an amino group from the viewpoint of the solubility of the pigment dispersion resin (A) and the dispersion stability of the conductive pigment paste. It is preferable to contain a solvent having a polar functional group such as an ether group.

Moreover, from the viewpoint of dispersibility of the conductive pigment paste and prevention of deterioration or hydrolysis of the resin, it is preferable that the paste does not substantially contain water. Here, "substantially free of water" means that the water content is usually 1% by mass or less, preferably 0.5% by mass or less, based on the total amount of the conductive pigment paste. It means that it is preferably 0.1% by mass or less.

In the present invention, the content of water in the conductive pigment paste can be measured by Karl Fischer coulometric titration. Specifically, using a Karl Fischer moisture content meter (manufactured by Kyoto Electronics Industry Co., Ltd., product name: MKC-610), a moisture vaporizer (manufactured by Kyoto Electronics Industry Co., Ltd., ADP-611) provided in the device The set temperature can be measured as 130°C.

From the viewpoint of the solubility of the pigment dispersion resin (A) and the dispersion stability of the conductive pigment paste, the solubility parameter δC of the solvent (C) is 10.0 (cal/cm ³ ) ^1/2 or more. preferably in the range of 10.4 to 15.0 (cal/cm ³ ) ^1/2 , more preferably in the range of 10.5 to 13.0 (cal/cm ³ ) ^1/2 is particularly preferred.

Solubility parameters of solvents can be determined according to the method described in J. Brandrup and E.H. Immergut, "Polymer Handbook" VII Solubility Parament Values, pp519-559 (John Wiley & Sons, 3rd edition, 1989). When two or more solvents are used in combination as a mixed solvent, the solubility parameters of the mixed solvent can be determined experimentally. It can also be obtained by the sum of the products of

The "solubility parameter of the solvent (C)" in the present invention is the solubility parameter of all the solvents (mixed solvent) contained in the conductive pigment paste.

From the viewpoint of the solubility of the pigment dispersion resin (A) and the dispersion stability of the conductive pigment paste, the difference between the solubility parameter δA of the pigment dispersion resin (A) and the solubility parameter δC of the solvent (C) |δA−δC | is preferably in the relationship |δA-δC|<2.1, more preferably |δA-δC|<2.0, and more preferably |δA-δC|<1.8. |δA−δC|<1.6 is more preferred.

<Conductive pigment paste>
The conductive pigment paste that can be used in the production method of the present invention optionally contains other components in addition to the above-described pigment dispersion resin (A), conductive pigment (B), and solvent (C). be able to.

Other components include a pigment dispersion resin other than the pigment dispersion resin (A), a film-forming resin, a neutralizer, an antifoaming agent, an antiseptic, an antirust agent, a plasticizer, a pigment other than the conductive pigment (B), and the like. can be mentioned.

Examples of the pigment dispersion resin other than the pigment dispersion resin (A) and the film-forming resin include acrylic resins other than the pigment dispersion resin (A), polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, and silicone resins. , polycarbonate resins, silicate resins, chlorine-based resins, fluorine-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 singly or in combination of two or more.

Among them, it is preferable to contain the film-forming resin (D). The film-forming resin (D) is a resin for the purpose of forming a coating film, and is a low-polarity resin that does not substantially contain the polar functional groups that are essential components of the pigment-dispersing resin (A). For example, the polar functional group concentration is less than 9 mmol/g, preferably 5 mmol/g or less, more preferably 1 mmol/g or less.

Preferred examples of the film-forming resin (D) include epoxy resins, urethane resins, chlorine resins, fluorine resins, styrene resins, diene resins, polyolefin resins, composite resins thereof, and the like. These resins can be used singly or in combination of two or more.

The film-forming resin (D) may be contained during pigment dispersion, or may be added and contained after pigment dispersion. The weight-average molecular weight of the film-forming resin (D) is preferably 100,000 or more, preferably 500,000 to 3,000, from the viewpoints of adhesion to the substrate, reinforcement of physical properties of the coating film, and solvent resistance. 000,000 is more preferred. The solubility parameter of the film-forming resin (D) is preferably less than 10, more preferably less than 9.3.

Further, from the viewpoint of the solubility and storage stability of the resin, the solubility parameter δD of the film-forming resin (D) and the solubility parameter δC of the solvent (C) have a |δD−δC|<3.0 relationship. is preferably More preferably, 0≤|δD-δC|≤2.8, and more preferably 0.1≤|δD-δC|≤2.5.

Moreover, the conductive pigment paste of the present invention preferably contains a highly polar low-molecular-weight component from the viewpoint of improving the wettability and/or dispersion stability of the conductive pigment.

The highly polar low-molecular-weight component is preferably basic or acidic, and may be partly or wholly a salt. Among them, base-containing low-molecular-weight components are preferred when the pigment is acidic, and acid-group-containing low-molecular-weight components are preferred when the pigment is basic.

It is preferable from the viewpoint of water resistance that the highly polar low molecular weight component does not remain in the conductive coating film or conductive material after solvent evaporation (heat drying) as much as possible, and the molecular weight is less than 1,000. Preferably, less than 400 is more preferred.

Organic acids, inorganic acids, organic bases and inorganic bases can be used as the highly polar low molecular weight component. Examples of organic acids include organic carboxylic acids (formic acid, glutamic acid, acetic acid, propionic acid, benzoic acid, phthalic acid, etc.) and organic sulfonic acids (benzenesulfonic acid, etc.). Acids and the like, organic bases such as amine compounds (pyridine, triethylamine, diazabicycloundecene, aniline, etc.), and inorganic bases such as metal hydroxides (sodium hydroxide, potassium hydroxide, etc.), ammonia, etc. are given respectively.

The content of the highly polar low molecular weight component is preferably 0.01 to 2.0% by mass, more preferably 0.02 to 1.0% by mass, based on the conductive pigment (B). more preferred.

Pigments other than the conductive pigment (B) include, for example, white pigments such as titanium white and zinc white; blue pigments such as cyanine blue and indanthrene blue; green pigments such as cyanine green and patina; and red pigments such as red iron oxide; organic yellow pigments such as benzimidazolone-based, isoindolinone-based, isoindoline-based and quinophthalone-based yellow pigments; and yellow pigments such as titanium yellow and yellow lead. These pigments can be used singly or in combination of two or more. Pigments other than these conductive pigments (B) can be used for purposes such as color adjustment and reinforcement of physical properties of the film within a range that does not significantly impair conductivity. It may be dispersed together with B), or the pigment-dispersing resin (A) and the conductive pigment (B) may be dispersed to prepare a paste and then mixed as a pigment or a pigment paste.

The content of pigments other than the conductive pigment (B) is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less, based on all pigments in the conductive pigment paste. It is especially preferable not to contain substantially.

The conductive pigment paste produced in the present invention can be newly mixed with the conductive pigment (B-3) after production.

The conductive pigment (B-3) added after production is preferably carbon nanotubes, conductive carbon, or the like from the viewpoint of conductivity, and may be a dispersion (paste) containing a dispersant, solvent, or the like. Further, the conductive pigment (B-3) and the mixture paste may be mixed after manufacturing the mixture paste to be described later.
When the conductive pigment (B-3) is added after the production of the conductive pigment paste, the content ratio of the conductive pigment (B) and the conductive pigment (B-3) is 1 in terms of solid content mass ratio. /99 to 99/1 are preferred.

<Method for producing conductive pigment paste>
In the method for producing the conductive pigment paste of the present invention, the components described above are mixed and dispersed using a medialess disperser.

Since the medialess dispersing machine does not contain balls, beads, etc. that serve as media, it is possible to mix and disperse the pigment while preventing the pigment from being destroyed or mixed with foreign matter during dispersion.

From the viewpoint of dispersibility and production efficiency, the medialess disperser used in the present invention preferably has a rotor and a stator in a casing, and the rotor and stator have mixing, dispersing, and pumping functions.

In the present invention, a powder raw material containing a conductive pigment (B) in a liquid raw material (L) obtained by mixing a pigment dispersion resin (A), a solvent (C), and optionally other components ( P) is added and mixed and dispersed using a medialess disperser.

The liquid raw material (L) is put into a medialess dispersing machine before the powdery raw material (P) is put. At this time, a plurality of components contained in the liquid raw material (L) may be mixed using a medialess disperser.

The raw material powder (P) may be added continuously, or may be added in multiple batches. Alternatively, the powdery raw material (P) may be fed by repeating a process of stopping the medialess dispersing machine, partially feeding the powdery raw material (P), and then operating the apparatus a plurality of times. However, from the viewpoint of efficient mixing and dispersion, it is more preferable to add the powder raw material (P) while operating the medialess disperser.

From the viewpoint of scattering prevention of the powdery raw material and production efficiency, the powdery raw material (P) is preferably introduced into the medialess disperser by suction. Among them, it is particularly preferable that the medialess dispersing machine has a rotor, and the powder raw material (P) is sucked into the dispersing machine by the negative pressure generated when the rotor rotates. When the powdery raw material (P) is sucked in by the negative pressure generated when the rotor rotates, the powdery raw material (P) can be gradually introduced into the system while the disperser is operating, which makes it more efficient. Dispersion becomes possible. Examples of commercial products of such a medialess disperser include Conti-TDS (trade name) manufactured by Dalton Co., Ltd., and CMX (trade name) manufactured by IKA.

In the present invention, in order to create a conductive paste with higher dispersibility, after mixing and dispersing with the above-mentioned medialess disperser, paint shaker, bead mill, ball mill, pebble ball mill, homogenizer, ultrasonic disperser, kneader , an extruder, and a planetary kneader. Among them, an annular bead mill, an ultrahigh-speed homogenizer, and a high-pressure homogenizer are suitable for additional dispersion.

An annular bead mill is a bead mill in which beads are filled inside a vessel container having a cylindrical rotor. The mechanism is such that the paste is dispersed when it passes between the rotating rotor and the inner wall surface of the vessel container. Since the paste passes through a relatively narrow area compared to other methods, unevenness of the beads and short paths are reduced, and the paste dispersion efficiency is uniform. Commercially available annular bead mills include, for example, EIRICH Co.: product name DCP Mill, Inoue Seisakusho Co.: product name Spike Mill, Asada Tekko Co., Ltd. product name Tough Mill, Ashizawa Finetech Co., Ltd. Co., Ltd.: trade name Starmill LMZ and the like.

From the viewpoint of dispersibility, the annular bead mill is more preferably of a biaxial drive system. In the present invention, a two-axis drive type annular bead mill is a bead mill in which a stator, screw, screen, etc. are formed inside a cylindrical rotor, and unevenness of beads and short passes are reduced compared to a single-axis drive type. be done. Specific examples of the biaxially driven annular bead mill include the bead mills described in JP-A-10-005560, JP-A-2003-1082, and JP-A-2006-7128. .

In the biaxially driven annular bead mill, it is preferable from the viewpoint of dispersibility that the screw, screen, etc. inside the rotor rotate. High-concentration paste can be dispersed by rotating in the direction opposite to the rotation of the rotor.

In the biaxial annular bead mill, as a mechanism for separating the dispersed paste, a screen type is used in JP-A-10-005560, etc., but the present invention is not limited to the screen type, Centrifugation type, gap type, etc. may be used.

The ultrahigh-speed homogenizer is a medialess disperser in which a rotor having inner blades rotates at high speed. Collisions with the high-speed rotating inner blade and shear force generated between the outer wall or the stationary outer blade due to the high-speed rotation make the particles finer and uniform. Commercially available ultra-high-speed homogenizers include, for example, Clearmix (trade name) manufactured by M Technic Co., Ltd., Filmix (trade name) manufactured by Primix Co., Ltd., and the like.

The high-pressure homogenizer is a medialess dispersing machine that disperses, refines, and homogenizes the paste by passing the paste through a narrow gap under pressure by a pump, and by using shearing force due to collision between particles and pressure difference. Commercially available high-pressure homogenizers include, for example, Yoshida Kikai Kogyo Co., Ltd.: product name Nanoveita, Sugino Machine Co., Ltd. product: product name Starburst.

<Mix paste>
The composite paste used in the production method of the present invention contains the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) contained in the conductive pigment paste as essential components, Further optionally, other ingredients such as resins, pigments, solvents, additives, etc. can be added to the conductive pigment paste.

Examples of resins include acrylic resins, polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, silicone resins, polycarbonate resins, silicate resins, chlorine resins, fluorine resins, polyvinylpyrrolidone resins, polyvinyl alcohol resins, Examples include polyvinyl acetal resins and composite resins thereof. These resins can be used singly or in combination of two or more.

Examples of pigments include coloring pigments, luster pigments, extender pigments, rust preventive pigments, and metal particles. These pigments can be used singly or in combination of two or more. Above all, when the mixture paste is used as the material for the battery electrode layer, it preferably contains an electrode active material. Examples of electrode active materials include lithium nickelate ( _LiNiO2 ), lithium manganate ( _LiMn2O4 ), lithium cobaltate ( _LiCoO2 ), LiNi1 _/3Co1 / _{3Mn1 / 3O2} , and the like _. Lithium compound oxide etc. are mentioned. These electrode active materials can be used individually by 1 type or in mixture of 2 or more types.
When the electrode active material is contained, the solid content of the electrode active material in the solid content of the mixture paste is usually 70 to 99.9% by mass, preferably 80 to 99% by mass. It is suitable in terms of battery resistance and the like.

The solvent is not particularly limited, but the same solvent as the solvent (C) described above can be preferably used. The above solvents may be used singly or in combination of two or more.

Additives include neutralizers, pigment dispersants, antifoaming agents, preservatives, rust preventives, plasticizers, viscosity modifiers and the like.

The content of the pigment dispersion resin (A) in the composite paste is usually 0.01 to 80% by mass, preferably 0.02 to 50% by mass, more preferably 0.02 to 50% by mass, based on the total solid content in the composite paste. 0.05 to 20% by mass, particularly preferably 0.08 to 10% by mass, is preferred from the viewpoints of viscosity, pigment dispersibility, storage stability, production efficiency, electrical conductivity, etc. when the pigment is dispersed.

The composite material paste is prepared by mixing each of the components described above with conventionally known methods such as dispersers, paint shakers, bead mills, ball mills, pebble ball mills, homogenizers, ultrasonic dispersers, kneaders, extruders, and planetary kneaders. It can be prepared by uniformly mixing or dispersing using a stirrer or disperser.

<Coating film (electrode layer)>
A coating film is formed by applying (coating) the above-described mixture paste to an object to be coated.

In the present invention, the coating film is a solid film obtained by applying a liquid mixture paste to an object (substrate) and drying it by heating, and peeling it off from the object to obtain a conductive film. Alternatively, a conductive material can be obtained by coating both sides of a plate-like object (substrate).

The object to be coated is not particularly limited, and examples thereof include metal materials; various plastic materials; inorganic materials such as glass, cement, and concrete; wood; It may be a composite material. In addition, these objects to be coated can optionally be subjected to degreasing treatment, surface treatment, or the like as appropriate.
In addition, it is preferable to apply|coat (coat) a coating film to a collector as a battery electrode layer.
The electrode layer can be used, for example, as a positive electrode or a negative electrode of a lithium ion battery.

The coating method is not particularly limited as long as it can be applied within a certain film thickness range. tar coating and the like.

The dry film thickness is preferably 1 to 200 μm, more preferably 2 to 150 μm.
The drying temperature is preferably 60 to 300°C, more preferably 80 to 200°C.

By heating and drying, the solvent contained in the mixture paste is preferably lost by 80% or more, more preferably by 90% or more, and particularly preferably by 95% or more. Moreover, when it contains a highly polar low-molecular-weight component, it is preferable that part or all of it disappears by the above heat drying.

EXAMPLES The present invention will be described in more detail below with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited thereto. "Parts" in each example means parts by mass, and "%" means % by mass.

<Method for producing pigment dispersion resin (A)>
Production Example 1 Production of Pigment Dispersion Resin A1 In a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas introduction tube and a stirrer, 90 parts of vinyl acetate and 10 parts of acrylic acid as polymerizable monomers, methanol as a solvent, and polymerization start. Using azobisisobutyronitrile as an agent, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a methanol solution of sodium hydroxide was added to conduct a saponification reaction, washed well, and dried with a hot air dryer to obtain a carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A1). The resulting pigment dispersion resin A1 has a saponification degree of 90 mol%, an SP value of 12.5 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 19.2 mmol/g, a carboxyl group concentration of 2.1 mmol/g, The weight average molecular weight was 17,000.

Production Example 2 Production of Pigment Dispersion Resin A2 Into a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas introduction tube and a stirrer, 90 parts of vinyl acetate as polymerizable monomers and 10 parts of acrylic acid, methanol as a solvent, and a polymerization initiator were charged. Using azobisisobutyronitrile as a copolymer, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added to conduct a saponification reaction, washed well, and then dried with a hot air dryer to obtain a carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A2). The resulting pigment dispersion resin A2 has a saponification degree of 60 mol %, an SP value of 11.2 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 10.1 mmol/g, a carboxyl group concentration of 1.7 mmol/g, The weight average molecular weight was 18,000.

Production Example 3 Production of Pigment Dispersion Resin A3 In a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube and a stirrer, 97 parts of vinyl acetate and 3 parts of vinylsulfonic acid as polymerizable monomers, methanol as a solvent, and polymerization. Using azobisisobutyronitrile as an initiator, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added for saponification reaction, and after thorough washing and drying with a hot air dryer, a sulfonic acid-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A3) was obtained. The resulting pigment dispersion resin A3 had a saponification degree of 97 mol%, an SP value of 12.5 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 21.1 mmol/g, and a sulfonic acid group concentration of 0.65 mmol/g. and a weight average molecular weight of 15,000.

Production Example 4 Production of Pigment Dispersion Resin A4 In a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas introduction tube and a stirrer, 97 parts of vinyl acetate and 3 parts of vinylsulfonic acid as polymerizable monomers, methanol as a solvent, and polymerization. Using azobisisobutyronitrile as an initiator, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added to conduct a saponification reaction, which was thoroughly washed and dried with a hot air dryer to obtain a sulfonic acid-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A4). The resulting pigment dispersion resin A4 has a saponification degree of 90 mol%, an SP value of 12.2 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 18.4 mmol/g, and a sulfonic acid group concentration of 0.61 mmol/g. and a weight average molecular weight of 16,000.

Production Example 5 Production of Pigment Dispersion Resin A5 90 parts of vinyl acetate and 10 parts of 1-pentene-4,5-diol as polymerizable monomers were placed in a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube and a stirrer. , methanol as a solvent, and azobisisobutyronitrile as a polymerization initiator, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added to conduct a saponification reaction, which was thoroughly washed and dried with a hot air dryer to obtain a diol-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A5). The resulting pigment dispersion resin A5 had a saponification degree of 90 mol %, an SP value of 12.6 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 22.7 mmol/g, and a weight average molecular weight of 15,000. .

Production Example 6 Production of Pigment Dispersion Resin A6 100 parts of vinyl acetate as a polymerizable monomer, methanol as a solvent, and azobisiso After performing a copolymerization reaction at a temperature of about 60° C. using butyronitrile, unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added to conduct a saponification reaction, which was thoroughly washed and dried with a hot air dryer to obtain a vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A6). The resulting pigment dispersion resin A6 had a saponification degree of 90 mol%, an SP value of 12.0 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 18.6 mmol/g, and a weight average molecular weight of 20,000. .

Production Example 7 Production of Pigment Dispersion Resin A9 Into a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas introduction tube and a stirrer, 90 parts of vinyl acetate and 10 parts of acrylic acid as polymerizable monomers, methanol as a solvent, and a polymerization initiator were charged. Using azobisisobutyronitrile as a copolymer, a copolymerization reaction was carried out at a temperature of about 60° C., and then unreacted monomers were removed under reduced pressure to obtain a resin solution. Next, a solution of sodium hydroxide in methanol was added to conduct a saponification reaction, which was thoroughly washed and dried with a hot air dryer to obtain a carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (pigment dispersion resin A9). The obtained pigment dispersion resin A9 has a saponification degree of 50 mol%, an SP value of 10.6 (cal/cm ³ ) ^1/2 , a hydroxyl group concentration of 5.9 mmol/g, a carboxyl group concentration of 1.5 mmol/g, and a weight of The average molecular weight was 20,000.

<Method for producing conductive pigment paste>
Examples 1-25, Comparative Examples 1-2
For the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Tables 1 to 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was The mixture was placed in a dispersing machine (manufactured by Dalton Co., Ltd.; product name: Conti-TDS), then the powder raw material of the conductive pigment (B) was sucked in, and mixing and dispersion were carried out 150 passes. Subsequently, 10 passes of dispersion treatment are performed with a biaxially driven annular bead mill described in JP-A-10-005560 to obtain conductive pigment pastes X-1 to X-25 and X-34 to X-35. rice field.

Example 26
Regarding the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Table 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was prepared using a medialess disperser. (manufactured by Dalton Co., Ltd.: trade name Conti-TDS), then the powder raw material of the conductive pigment (B) is sucked in, mixed and dispersed 800 passes, and the conductive pigment paste X-26 got

Example 27
Regarding the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Table 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was prepared using a medialess disperser. (manufactured by Dalton Co., Ltd.: trade name Conti-TDS), then the powder raw material of the conductive pigment (B) was sucked in, and mixed and dispersed for 150 passes. Subsequently, dispersion treatment was carried out 40 passes in a uniaxially driven annular bead mill (manufactured by Ashizawa Finetech Co., Ltd.; trade name Starmill LMZ) to obtain a conductive pigment paste X-27.

Example 28
Regarding the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Table 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was prepared using a medialess disperser. (manufactured by Dalton Co., Ltd.: trade name Conti-TDS), then the powder raw material of the conductive pigment (B) was sucked in, and mixed and dispersed for 150 passes. Subsequently, dispersion treatment was carried out 600 passes using an ultra-high-speed homogenizer (manufactured by Primix Co., Ltd.; product name Filmix) to obtain a conductive pigment paste X-28.

Example 29
Regarding the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Table 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was prepared using a medialess disperser. (manufactured by Dalton Co., Ltd.: trade name Conti-TDS), then the powder raw material of the conductive pigment (B) was sucked in, and mixed and dispersed for 150 passes. Subsequently, dispersion treatment was carried out 10 passes with a high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.; trade name: Nanoveita) to obtain a conductive pigment paste X-29.

Example 30
Regarding the types and amounts of pigment dispersion resin (A), conductive pigment (B), and solvent (C) described in Table 3, a liquid raw material obtained by dissolving pigment dispersion resin (A) in solvent (C) was prepared using a medialess disperser. (manufactured by Dalton Co., Ltd.: trade name Conti-TDS), then the powder raw material of the conductive pigment (B) was sucked in, and mixed and dispersed for 150 passes. Subsequently, dispersion treatment was carried out 110 passes in a disk-shaped bead mill (manufactured by Shinmaru Enterprises Co., Ltd.; product name: DYNO-MILL) to obtain a conductive pigment paste X-30.

Example 31
Regarding the types and amounts of the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) shown in Table 3, the pigment dispersion resin (A) was dissolved in the solvent (C) as a liquid raw material and the conductive pigment. (B) was put into a homogenizer (manufactured by IKA, trade name: ULTRA-TURRAX) and mixed and dispersed for 1.5 hours to obtain a conductive pigment paste X-31.

Example 32
Regarding the types and amounts of the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) shown in Table 3, the pigment dispersion resin (A) was dissolved in the solvent (C) as a liquid raw material and the conductive pigment. (B) was put into a homogenizer (manufactured by IKA, trade name: ULTRA-TURRAX) and mixed and dispersed for 1.5 hours. Subsequently, 10 passes of dispersion treatment were performed using a biaxially driven annular bead mill described in JP-A-10-005560 to obtain a conductive pigment paste X-32.

Example 33
Regarding the types and amounts of the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) shown in Table 3, the pigment dispersion resin (A) was dissolved in the solvent (C) as a liquid raw material and the conductive pigment. (B) was put into a homogenizer (manufactured by IKA, trade name: ULTRA-TURRAX) and mixed and dispersed for 1.5 hours. Subsequently, dispersion treatment was carried out 600 passes using an ultra-high-speed homogenizer (manufactured by Primix Co., Ltd.; product name Filmix) to obtain a conductive pigment paste X-33.

Comparative example 3
Regarding the types and amounts of the pigment dispersion resin (A), the conductive pigment (B), and the solvent (C) shown in Table 3, the pigment dispersion resin (A) was dissolved in the solvent (C) as a liquid raw material and the conductive pigment. (B) was placed in a disk-shaped bead mill (manufactured by Shinmaru Enterprises Co., Ltd.; product name: DYNO-MILL) and dispersed for 110 passes to obtain a conductive pigment paste X-36.

<Table 1>

<Table 2>

<Table 3>

The pigment dispersing resin (A) type, conductive pigment (B) type, solvent (C) type, and dispersion type in the table are shown below.

[Pigment dispersion resin (A)]
The amount of the pigment dispersing resin in the table is the value of the solid content.
A1: Carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 90 mol%, SP value: 12.5, hydroxyl group concentration: 19.2 mmol/g, carboxyl group concentration: 2.1 mmol/g, weight average molecular weight: 17 ,000)
A2: Carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 60 mol%, SP value: 11.2, hydroxyl group concentration: 10.1 mmol/g, carboxyl group concentration: 1.7 mmol/g, weight average molecular weight: 18 ,000)
A3: Sulfonic acid-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 97 mol%, SP value: 12.5, hydroxyl group concentration: 21.1 mmol/g, sulfonic acid group concentration: 0.65 mmol/g, weight average molecular weight: 15,000)
A4: Sulfonic acid-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 90 mol%, SP value: 12.2, hydroxyl group concentration: 18.4 mmol/g, sulfonic acid group concentration: 0.61 mmol/g, weight average molecular weight: 16,000)
A5: Diol-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 90 mol%, SP value: 12.6, hydroxyl group concentration: 22.7 mmol/g, weight average molecular weight: 15,000)
A6: Vinyl acetate-vinyl alcohol copolymer (degree of saponification: 90 mol%, SP value: 12.0, hydroxyl group concentration: 18.6 mmol/g, weight average molecular weight: 20,000)
A7: Polyvinylpyrrolidone (SP value: 12.8, amide group concentration: 9.1 mmol/g, weight average molecular weight: 10,000)
A8: Polyacrylic acid (SP value: 13.0, carboxyl group concentration: 13.9 mmol/g, weight average molecular weight: 15,000)
A9: Carboxylic acid-modified vinyl acetate-vinyl alcohol copolymer (degree of saponification 50 mol%, SP value: 10.6, hydroxyl group concentration: 5.9 mmol/g, carboxyl group concentration: 1.5 mmol/g, weight average molecular weight: 20 ,000)
A10: Polymethyl methacrylate (SP value: 9.23, polar group concentration 0 mmol/g, weight average molecular weight: 21,000)

[Conductive pigment (B)]
B1: carbon nanotube (multi-layer, average outer diameter: 9 nm, average length: 20 μm)
B2: carbon nanotube (multi-layer, average outer diameter: 13 nm, average length: 30 μm)
B3: carbon nanotube (multi-layer, average outer diameter: 150 nm, average length: 6 μm)
B4: carbon black (acetylene black, average primary particle size: 50 nm)
B5: carbon black (acetylene black, average primary particle size: 20 nm)
B6: graphite (average primary particle size: 10 μm)

[Solvent (C)]
C1: N,N-dimethylacetamide (SP value: 11.1)
C2: N-methyl-2-pyrrolidone (SP value: 11.2)
C3: n-butanol (SP value: 11.4)
C4: propylene glycol monomethyl ether (SP value: 10.4)

[Disperser]
α: Medialess disperser (manufactured by Dalton Co., Ltd.: trade name Conti-TDS)
β: Homogenizer (manufactured by IKA: trade name ULTRA-TURRAX)
γ: 2-axis drive type annular disperser described in JP-A-10-005560 δ: 1-axis drive type annular bead mill (manufactured by Ashizawa Finetech Co., Ltd.: trade name Star Mill LMZ)
ε: Ultra-high-speed homogenizer (manufactured by Primix Co., Ltd.: trade name Filmix)
ζ: High-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.: trade name Nanoveita)
η: disk-shaped bead mill (manufactured by Shinmaru Enterprises Co., Ltd.: trade name DYNO-MILL)

<Evaluation test>
The conductive pigment paste prepared by the above manufacturing method was evaluated by the following evaluation method. The evaluation results are shown in Tables 1-3. In the present invention, it is important that the performance of all items in the evaluation test is excellent, and if any one of them is evaluated as "C", the conductive pigment paste is rejected.

[amount of water]
The water content of the obtained conductive pigment paste was measured using a Karl Fischer moisture content meter (manufactured by Kyoto Electronics Industry Co., Ltd., product name: MKC-610), and a moisture vaporizer (Kyoto Electronics Co., Ltd. ), ADP-611) was measured with a set temperature of 130°C.
The water content was calculated based on the total amount of the conductive pigment paste, and evaluated according to the following criteria.
S: The water content is less than 0.1% by mass.
A: Moisture content is 0.1% by mass or more and less than 0.5% by mass.
B: Moisture content is 0.5% by mass or more and less than 1% by mass.
C: Moisture content is 1% by mass or more.

[viscosity]
The viscosity of the obtained conductive pigment paste was measured at a shear rate of 1.0 sec ⁻¹ using a cone and plate type viscometer (HAAKE, trade name: Mars2, diameter 35 mm, cone and plate inclined at 2°). and evaluated according to the following criteria.
S: The viscosity is less than 1.0 Pa·s.
A: The viscosity is 1.0 Pa·s or more and less than 2.0 Pa·s.
B: The viscosity is 2.0 Pa·s or more and less than 5.0 Pa·s.
C: Viscosity is 5.0 Pa·s or more.

[Storage stability (rate of viscosity increase)]
The obtained pigment-dispersed paste was stored at a temperature of 50° C. for one month, and the initial viscosity and the viscosity after storage were compared. The viscosity is measured using a cone & plate type viscometer (HAAKE, trade name: Mars2, diameter 35 mm, cone & plate inclined at 2°) at a shear rate of 1.0 s ^-1 , and the viscosity increase rate is calculated by the following formula. evaluated.

Viscosity increase rate (%) = Viscosity after storage/Initial viscosity x 100-100
S: Viscosity increase rate (%) after storage is less than 30%.
A: The viscosity increase rate (%) after storage is 30% or more and less than 100%.
B: Viscosity increase rate (%) after storage is 100% or more and less than 200%.
C: Viscosity increase rate (%) after storage is 200% or more.

[Conductivity (volume resistivity)]
In volume resistivity measurement, KF Polymer L#7305 (trade name, 5% solution of polyvinylidene fluoride, solvent N-methyl-2-pyrrolidone, manufactured by Kureha Corporation) was used as a binder.

The conductive pigment pastes of Examples 1 to 16, 21, 23 to 33, and Comparative Examples 1 to 2 and 4 using carbon nanotubes (or mainly carbon nanotubes) as conductive pigments were measured by the following method. , made an evaluation.

Each of the conductive pigment pastes obtained in Examples and Comparative Examples and the KF polymer were mixed so that the mass ratio of the conductive pigment in the conductive pigment paste and the polyvinylidene fluoride in KF Polymer L#7305 was 5:100. L#7305 was weighed and mixed with an ultrasonic homogenizer for 2 minutes to obtain a coating material.

The coating material was applied to a glass plate (2 mm×100 mm×150 mm) by a doctor blade method and dried by heating at 130° C. for 30 minutes. After measuring the thickness of the obtained coating film, the resistance was measured with a source meter (2400, manufactured by Keithley Co., Ltd.) using a four-point probe (PSP, manufactured by Mitsubishi Chemical Corporation). The film thickness of the coating film and the resistance value were multiplied to obtain the volume resistivity. As the evaluation, S, A, B, and C are acceptable, and D is unacceptable.
S: The volume resistivity is less than 10 Ω·cm, and the electrical conductivity is very good.
A: The volume resistivity is 10 Ω·cm or more and less than 15 Ω·cm, and the conductivity is good.
B: The volume resistivity is 15 Ω·cm or more and less than 20 Ω·cm, and the conductivity is normal.
C: The volume resistivity is 20 Ω·cm or more, and the electrical conductivity is poor. Alternatively, a smooth coating film could not be formed.

For the conductive pigment pastes of Examples 17 to 20, 22, and Comparative Example 3 using carbon black (acetylene black) or graphite (or mainly using carbon black (acetylene black)) as the conductive pigment, the following method was used. was measured and evaluated.
Each conductive pigment paste and KF polymer obtained in Examples and Comparative Examples were mixed so that the mass ratio of the conductive pigment in the conductive pigment paste and the polyvinylidene fluoride in KF Polymer L#7305 was 85:10. L#7305 was weighed and mixed with an ultrasonic homogenizer for 2 minutes to obtain a coating material.

Two aluminum foil tapes (No. 425, manufactured by Sumitomo 3M Co., Ltd.) were pasted in parallel on a polypropylene plate (10 cm x 15 cm x 3 mm) at intervals of 3 cm. Next, the resulting coating material was applied between aluminum foil tapes with an applicator to a length of 5 cm and a dry film thickness of 15 μm, allowed to stand at room temperature for 2 minutes, and then dried by heating at 80° C. for 10 minutes. A dry coating film of width 3 cm x length 5 cm x thickness 15 µm was prepared.

The volume resistivity of the dry coating film applied between the aluminum foil tapes was measured using a measuring machine (manufactured by Yokogawa Keisoku Co., Ltd., trade name digital multimeter MODEL 73401) at 20 ° C. and a relative humidity of 65%. The conductivity was evaluated by
S: The volume resistivity is less than 0.005 Ω·m, and the electrical conductivity is very good.
A: The volume resistivity is 0.005 Ω·m or more and less than 0.008 Ω·m, and the conductivity is good.
B: The volume resistivity is 0.008 Ω·m or more and less than 0.01 Ω·m, and the conductivity is slightly inferior.
C: The volume resistivity is 0.01 Ω·m or more, and the electrical conductivity is very poor.

<Manufacturing of composite paste and electrode layer>
Application examples Y-1 to Y-33, Z-1 to Z-33
In 100 parts of the conductive pigment paste obtained in Examples 1 to 33, 50 parts of N,N-dimethylacetamide as a solvent, 1 part of polyvinylidene fluoride (weight average molecular weight 800,000), and active material particles (lithium 50 parts of nickel manganese oxide, average particle size: 5 μm) was added and mixed and stirred for 60 minutes using a disper to obtain mixture pastes Y-1 to Y-33 as application examples Y-1 to Y-33. .

Subsequently, the above mixture pastes Y-1 to Y-33 are applied on an aluminum foil (current collector) with an applicator so that the dry film is 10 μm, dried at a temperature of 180 ° C. for 40 minutes, and applied examples Electrode layers Z-1 to Z-33, which become Z-1 to Z-33, were obtained.

All of the obtained electrode layers had a residual solvent amount of less than 1%, and were electrode layers with good finish and good battery performance.

Claims (24)

A method for producing a conductive pigment paste containing a pigment dispersion resin (A), a conductive pigment (B), and a solvent (C),
The pigment dispersion resin (A) has at least one polar functional group selected from the group consisting of an amide group, an imide group, an ether group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a silanol group, and an amino group. and the pigment dispersion resin (A) has a polar functional group concentration of 9 to 23 mmol/g,
The conductive pigment (B) contains carbon nanotubes (B-1) and/or conductive carbon (B-2) having an average primary particle diameter of 10 to 80 nm,
Powder raw material (P) containing conductive pigment (B) is added to liquid raw material (L) obtained by mixing pigment dispersion resin (A), solvent (C), and optionally other components. and mix and disperse with a medialess disperser,
A method for producing a conductive pigment paste. The conductive pigment paste according to claim 1, wherein the medialess dispersing machine has a rotor and a stator in a casing, and the rotor is rotated to perform mixing, dispersion, and pumping. Method. 3. The method for producing a conductive pigment paste according to claim 2, wherein the powder raw material (P) is sucked in using negative pressure generated when a rotor rotates. After mixing and dispersing by the medialess disperser, at least one disperser selected from the group consisting of a paint shaker, a bead mill, a ball mill, a pebble ball mill, a homogenizer, an ultrasonic disperser, a kneader, an extruder, and a planetary kneader. A method for producing a conductive pigment paste according to any one of claims 1 to 3, characterized in that additional dispersion is performed by a machine. 5. The method for producing a conductive pigment paste according to claim 4, wherein the dispersing machine used for additional dispersion is an annular bead mill. 6. The method of producing a conductive pigment paste according to claim 5, wherein the annular bead mill is a biaxially driven annular bead mill. 5. The method for producing a conductive pigment paste according to claim 4, wherein the disperser used for additional dispersion is an ultra-high speed homogenizer or a high pressure homogenizer. The method for producing a conductive pigment paste according to any one of claims 1 to 7, wherein the pigment dispersion resin (A) contains ionic polyvinyl alcohol. The method for producing a conductive pigment paste according to claim 8, wherein the degree of saponification of the ionic polyvinyl alcohol is 85 mol% or more and less than 100 mol%. The conductive according to any one of claims 1 to 9, wherein the solid content of the pigment dispersion resin (A) is 0.1 to 50% by mass based on the total solid content of the conductive pigment paste. A method for producing a pigment paste. The conductive pigment (B) contains carbon nanotubes (B-1), and the solid content of the pigment dispersion resin (A) is 5 to 50% by mass based on the total solid content of the conductive pigment paste. , a method for producing a conductive pigment paste according to any one of claims 1 to 10. The conductive pigment (B) does not contain carbon nanotubes (B-1), and the solid content of the pigment dispersion resin (A) is 0.1 to 20 mass based on the total solid content of the conductive pigment paste. %, the method for producing a conductive pigment paste according to any one of claims 1 to 10. The content of the conductive pigment (B) is 1 to 90% by mass based on the total amount of the conductive pigment paste, and 10 to 99.9% by mass based on the total solid content of the conductive pigment paste. A method for producing a conductive pigment paste according to any one of claims 1 to 12. The conductive pigment (B) contains carbon nanotubes (B-1), the content of the carbon nanotubes (B-1) is 1 to 20% by mass based on the total amount of the conductive pigment paste, and the conductive The method for producing the conductive pigment paste according to any one of claims 1 to 11 and 13, which is 10 to 99% by mass based on the total solid content of the conductive pigment paste. The conductive pigment (B) contains conductive carbon (B-2) having an average primary particle diameter of 10 to 80 nm, and the content of the conductive carbon (B-2) is based on the total amount of the conductive pigment paste. The conductive pigment paste according to any one of claims 1 to 14, which is 5 to 90% by mass and 40 to 99.9% by mass based on the total solid content of the conductive pigment paste. How to manufacture The method for producing a conductive pigment paste according to any one of claims 1 to 11 and 13 to 15, wherein the carbon nanotubes (B-1) contain multi-walled carbon nanotubes. The conductive pigment (B) contains conductive carbon (B-2) having an average primary particle size of 10 to 80 nm, and the conductive carbon (B-2) is acetylene black, ketjen black, furnace black, thermal black. , graphene, and graphite, the method for producing a conductive pigment paste according to any one of claims 1 to 16. 18. Any one of claims 1 to 17, 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 to 15.0. A method for producing the conductive pigment paste according to . 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|<2.1, according to any one of claims 1 to 18. A method for producing a conductive pigment paste of The conductive pigment paste according to any one of claims 1 to 19, wherein the liquid raw material (L) is produced by dissolving the pigment dispersion resin (A) in the solvent (C) heated to 50 ° C. or higher. How to manufacture. A method for producing a conductive pigment paste, wherein the conductive pigment paste obtained by the method according to any one of claims 1 to 20 contains substantially no water. A method for producing a conductive pigment paste, wherein the conductive pigment paste obtained by the method according to any one of claims 1 to 21 contains substantially no metal. A method for producing a mixture paste, comprising adding at least one electrode active material to the conductive pigment paste produced by the method according to any one of claims 1 to 22. A method for producing a battery electrode layer obtained by coating a current collector with the mixture paste obtained by the method according to claim 23 .