JP2015128006A - Aqueous conductive paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous conductive paste which contains a carbon material having high conductivity and satisfies both of high conductivity and low viscosity.SOLUTION: Provided is an aqueous conductive paste comprising a carbon material, a dispersant, and an aqueous medium. The carbon material has an ash content of 1 mass% or less, a volume resistivity value of 0.2 Ωcm or less, and a BET specific surface area of 500 m/g to 2630 m/g. The dispersant contains an anionic polymer dispersant, where the anionic polymer is a neutralized material of a polymer having a weight average molecular weight of 5000 to 100000, raw material monomers of which includes at least 10 to 90 mass% of a radical-polymerizable monomer having an acidic group and 10 to 70 mass% of a radical-polymerizable monomer having a hydrophobic group, and when the amount by mole of the total acidic groups is set as 100 moles, 30 to 100 moles thereof is neutralized with lithium ions.

Description

  The present invention relates to an aqueous conductive paste and a method for producing the same.

  In general, conductive pastes are widely used in the production of conductive resins, battery materials, adhesive materials and the like. Among these, aqueous conductive pastes containing carbon materials have recently been attracting attention from the viewpoint of low VOC (Volatile organic compounds) and low environmental load, and are showing an increasing demand.

  As an aqueous conductive paste containing a carbon material for producing a conductive resin, Patent Document 1 discloses a carbon black dispersion for producing a conductive urethane containing a binder composed of a specific core-shell type polymer emulsion.

  As an aqueous conductive paste containing a carbon material used for manufacturing battery materials, Patent Document 2 discloses a polar dispersion composition in which a specific conductive carbon black is dispersed in a polar dispersion medium by a nonionic dispersant. Things are disclosed. By applying a coating liquid obtained by mixing the polar dispersion composition and the binder resin, a conductive coating film can be obtained.

  Patent Document 3 discloses a conductive material dispersion containing a specific carbon black, a nonionic dispersant, and a dispersion medium as a positive electrode material for a lithium ion battery.

JP 2001-164078 A WO2010-123137 JP 2011-70908 A

  However, in recent demands, for conductive resins, battery materials have improved active material ratios and coating films due to reasons such as the foaming characteristics of conductive polyurethane foam and the increase in the resin content for improving product performance. From the viewpoint of expressing high conductivity with a low addition amount of the carbon material, and from the viewpoint of improving handling properties and miscibility, a conductive slurry containing a carbon material having a lower viscosity is provided. In the prior art described above, the actual situation is that the request is not sufficiently met.

  In the case of secondary batteries that use acetylene black widely, instead of acetylene black, use a carbon material with a very large specific surface area such as ketjen black, carbon nanotube, graphene, etc. with higher conductivity. Is required. However, since these carbon materials have a large specific surface area, their dispersibility is greatly deteriorated, and at present, they are only used in applications where coating properties are not important.

  On the other hand, the dispersant reduces the viscosity of the conductive paste and improves the miscibility at the time of blending the ingredients and the coating property of the coating liquid, and it can be applied to a conductive material such as a carbon material as much as possible in order not to lower the conductivity. It is required to be blended in a small amount.

  In the above-mentioned patent document, some nonionic polymer dispersants are described as dispersants, and the viscosity reducing effect by the dispersants is shown. However, when the carbon material having high conductivity is used, From the viewpoint of achieving both high conductivity and low viscosity, it is difficult to say that the conventional aqueous conductive paste is at a sufficient level.

  The present invention provides an aqueous conductive paste that includes a carbon material having high conductivity and has both high conductivity and low viscosity.

The aqueous conductive paste of the present invention contains a carbon material, a dispersant, and an aqueous medium,
Of the carbon material, ash content is less than 1% or less, the volume resistivity of 0.2Ωcm or less, the BET specific surface area of less 500 meters ² / g or more 2630 m ² / g,
The dispersant includes an anionic polymer dispersant,
The anionic polymer dispersant has at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group. A neutralized product of a polymer having a weight average molecular weight of 5,000 to 100,000 and having a weight average molecular weight of 5,000 to 100,000, wherein 30 to 100 moles are neutralized with lithium ions when the total number of acidic groups is 100 moles.

The method for producing the aqueous conductive paste of the present invention comprises:
Ash content less than 1 wt%, the volume resistivity of 0.2Ωcm or less, BET specific surface area and less of the carbon material 500 meters ² / g or more 2630 m ² / g, the raw material monomers, a radical polymerizable monomer having at least an acidic group 10% to 90% by mass and 10% by mass to 70% by mass of a radically polymerizable monomer having a hydrophobic group, and 30 mol to 100 mol when the total number of acidic groups is 100 mol is lithium ion. A step of mixing the aqueous medium with an anionic polymer dispersant, which is a neutralized polymer having a weight average molecular weight of 5,000 to 100,000,
The carbon material, the polymer non-neutralized product or the polymer neutralized product in which a part of the acidic group is neutralized by lithium ions, and the aqueous medium are mixed or mixed. Thereafter, the method includes a step of neutralizing the acidic group with lithium ions to obtain a mixed liquid containing the carbon material, the anionic polymer dispersant, and the aqueous medium.

  According to the present invention, it is possible to provide an aqueous conductive paste that includes a highly conductive carbon material and has both high conductivity and low viscosity, and therefore has both high conductivity and low viscosity. It is possible to provide a functional resin, a battery material, and the like.

The present inventors have found that the aqueous conductive paste can achieve both high conductivity and low viscosity by including the following carbon material (component A), dispersant (component B), and aqueous medium (component C). I found it.
(Component A): ash content less than 1 wt%, the volume resistivity of 0.2Ωcm or less, BET specific surface area 500 meters 2630 m of ² / g or less ² / g or more, a carbon material (Component B): an anionic polymer dispersion Dispersant containing agent. The anionic polymer dispersant contains 10% by mass to 90% by mass of a radically polymerizable monomer having at least an acidic group and 10% by mass to 70% by mass of a radically polymerizable monomer having a hydrophobic group. A neutralized product of a polymer having a weight average molecular weight of 5,000 to 100,000, in which 30 to 100 moles are neutralized with lithium ions when the number of moles of all acidic groups is 100 moles.
(Component C): Aqueous medium

  The details of the mechanism of the effect of the present invention are not clear, but are estimated as follows.

For example, the conductive carbon material has an ash content of 1% by mass or less and a volume resistivity value of 0.2 Ωcm or less, thereby ensuring the conductivity inherent to the material and having a BET specific surface area of 500 m ² / g or more. It is considered that the formation of a conductive path between the carbon material particles is facilitated by being 2630 m ² / g or less. However, such a carbon material having a large BET specific surface area has a high surface hydrophobicity and causes strong agglomeration, so that it cannot be substantially used as a raw material for paste. On the other hand, the raw material monomer contains at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group, Anionic high molecular weight neutralized product having a weight average molecular weight of 5,000 to 100,000, in which 30 to 100 moles of the total number of acidic groups is neutralized by lithium ions when the number of moles of all acidic groups is 100 moles. By coexisting the molecular dispersant with the carbon material, the dispersibility of the carbon material having a large specific surface area, which has been difficult in the past, is improved, and furthermore, it is possible to achieve both high conductivity and low viscosity of the aqueous conductive paste. It is thought that it becomes. Lithium ions neutralizing part or all of the anionic polymer dispersant are considered to contribute to the improvement of the dispersibility of the carbon material and also to form the conductive path of the aqueous conductive paste. doing. However, these are estimations, and the present invention is not limited to these mechanisms.

  "The raw material monomer contains at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group, A polymer neutralized product having a weight average molecular weight of 5,000 to 100,000 and having a weight average molecular weight of 5,000 to 100,000 is neutralized by lithium ions when the number of moles is 100 moles. After obtaining a molecule, it may be a polymer neutralized product obtained by neutralizing a part or all of all acidic groups, or neutralize part or all of acidic groups possessed by the raw material monomer. Then, the raw material monomer is polymerized to obtain a polymer, and if necessary, a neutralized product of the polymer may be obtained by further neutralizing some or all of the acidic groups.

  The aqueous conductive paste of the present invention contains at least a carbon material, a dispersant, and an aqueous medium.

[Carbon material]
In the carbon material (component A), from the viewpoint of improving conductivity and reducing the possibility of causing secondary troubles due to ash elution, the ash content is 1% by mass or less, and the carbon content is Preferably it is 99.5% or more, more preferably 99.8% or more. The ash content in the carbon material can be measured by the method described in JIS K 6218-2.

The volume resistivity of the carbon material is 0.2 Ωcm or less, preferably 0.15 Ωcm or less, more preferably 0.1 Ωcm or less, from the viewpoint of achieving both high conductivity and low viscosity. The volume resistivity value of the carbon material is a value obtained by measuring the conductive resistance when only the carbon material is pressed at a pressure of 120 kg / cm ² , and can be measured by the method described in the following document.
J. Sanchez-Gonzalez et al. Carbon 43 (2005) p741-747

  For some types of carbon black, specific numerical values are described in the Carbon Black Association, Carbon Black Handbook <Third Edition>, p553.

The BET specific surface area of the carbon material, from the viewpoint of compatibility of high conductivity and low viscosity, 500 meters ² / g or more 2630m and ² / g or less, preferably 600 meters ² / g or more, more preferably 700 meters ² / g or more, preferably 2000 m ² / g or less, more preferably 1500 m ² / g or less. The BET specific surface area of the carbon material can be measured by the method described in JIS Z8830 and the following documents.
S.BRUNAUER, PHEMMETT, E.TELLER, J.Am.Chem.Soc.1938, 60, pp.309-319

  The carbon material (component A) includes carbon black, graphite, and ash, volume resistivity, and BET specific surface area within the ranges described above from the viewpoint of achieving both high conductivity and low viscosity. (Graphite), carbon nanotube, graphene and the like. These carbon materials may be used alone or in admixture of two or more. In particular, the carbon material (component A) preferably contains ketjen black, which is a kind of carbon black, from the viewpoint of achieving both high conductivity and low viscosity, and more preferably composed of ketjen black alone.

[Dispersant]
The dispersant (component B) contains an anionic polymer dispersant as a main component, and the anionic polymer dispersant is 100% by mass of the total amount of raw material monomers used for the production of the anionic polymer dispersant. The raw material monomer contains at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group, Among them, 30 mol% or more and 100 mol% or less is a lithium ion, and a neutralized product of a polymer having a weight average molecular weight of 5000 or more and 100,000 or less. If the main component of the dispersant is the anionic polymer dispersant, other dispersants may be used in combination, but the content of the anionic polymer dispersant in the dispersant is high conductivity and low viscosity. From the viewpoint of coexistence, it is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably substantially 100% by mass, and even more preferably 100% by mass.

  Examples of the other dispersant contained in the dispersant (component B) include nonionic polymer dispersants, cationic polymer dispersants, amphoteric polymer dispersants, and low molecular surfactants.

  The weight average molecular weight of the anionic polymer dispersant is 5000 or more and 100,000 or less, preferably 8000 or more, more preferably 10,000 or more, and further preferably 15000 or more from the viewpoint of achieving both high conductivity and low viscosity. , Preferably 80000 or less, more preferably 60000 or less, still more preferably 50000 or less. The method for measuring the weight average molecular weight of the anionic polymer dispersant is as described in the examples.

  The anionic polymer dispersant contains 10% by mass or more and 90% by mass or less, preferably 30% by mass or more, of a radically polymerizable monomer having an acidic group as a raw material monomer from the viewpoint of achieving both high conductivity and low viscosity. More preferably, the polymer neutralized product contains 45% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less.

  The radical polymerizable monomer having an acidic group is an unsaturated monomer having an acidic group such as carboxylic acid or sulfonic acid, and includes an acid anhydride and an acid halide as a form before neutralization. Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and anhydrides, halides, half esters and half amides thereof. Examples of the sulfonic acid monomer include allyl sulfonic acid, vinyl sulfonic acid, methallyl sulfonic acid, and styrene sulfonic acid. These can be used alone or in admixture of two or more. Among these radically polymerizable monomers having an acidic group, at least one monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and maleic anhydride is preferable from the viewpoint of achieving both high conductivity and low viscosity. . These monomers may have some or all of the acidic groups previously neutralized, and are polymerized using an unneutralized monomer to neutralize some or all of the acidic groups of the resulting polymer. May be.

  From the viewpoint of achieving both high conductivity and low viscosity, the anionic polymer dispersant contains 10% by mass or more and 70% by mass or less, preferably 20% by mass or more, of a radical polymerizable monomer having a hydrophobic group as a raw material monomer. More preferably, it is 30% by mass or more, preferably 60% by mass or less, more preferably 55% by mass or less. The radically polymerizable monomer having a hydrophobic group is a monomer having a solubility of 3 g or less, preferably 1 g or less, in 100 g of water at 20 ° C.

  The radical polymerizable monomer having a hydrophobic group is a compound having a carbon-carbon unsaturated bond and a hydrophobic functional group such as an alkyl group, an alkenyl group, and an aryl group in one molecule. Specifically, an alkyl group (Meth) acrylic acid ester, vinyl ether, unsaturated dibasic acid diester, vinyl ester and allyl ester having a hydrophobic functional group such as alkenyl group and aryl group, styrenes and olefins. (Meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid 2 -Ethylhexyl, octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic Examples include benzyl acid. As unsaturated dibasic acid diesters, dimethyl maleate, diethyl maleate, dibutyl maleate, bis (2-ethylhexyl) maleate, dioctyl maleate, dilauryl maleate, distearyl maleate, dimethyl itaconate, diethyl itaconate , Dibutyl itaconate, bis (2-ethylhexyl) itaconate, dilauryl itaconate, distearyl itaconate and the like. Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate, vinyl stearate, vinyl 2-ethylhexanoate, vinyl benzoate and the like. Examples of allyl esters include allyl acetate, allyl butyrate, allyl propionate, allyl 2-ethylhexanoate, allyl laurate, and allyl stearate. Examples of styrenes include styrene, α-methylstyrene, and p-methylstyrene. As the olefins, α-olefins are preferable, as branched α-olefins, isobutylene, diisobutylene, and the like are used as linear α-olefins. 1-eicosene and the like. These can be used alone or in admixture of two or more. Among these radically polymerizable monomers having a hydrophobic group, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth) from the viewpoint of achieving both high conductivity and low viscosity. ) At least one monomer selected from the group consisting of benzyl acrylate, styrene, isobutylene, diisobutylene, 1-octadecene, and 1-eicosene is preferred, lauryl (meth) acrylate, stearyl (meth) acrylate, and di At least one selected from the group consisting of isobutylene is more preferable, and at least one selected from stearyl (meth) acrylate and diisobutylene is still more preferable.

  In the anionic polymer dispersant, from the viewpoint of achieving both high conductivity and low viscosity, lithium having 30 to 100 moles as a counter ion when the number of moles of all acidic groups of the polymer is 100 moles. Although neutralized by ions, preferably 40 moles or more, more preferably 50 moles or more are neutralized by lithium ions. Of the total acidic groups, acidic groups that do not have lithium ions as counter ions are unneutralized or have other cations as counter ions. Examples of other cations include ammonium ion, sodium ion, potassium ion, calcium ion, magnesium ion, and aluminum ion, and ammonium ion and sodium ion are preferable.

  The acidic group may be neutralized at the time of the monomer, may be neutralized after polymerization, or may be neutralized after polymerization by neutralizing a part or all of the acidic group with another neutralizing agent. Ion substitution may be performed. From the viewpoint of improving productivity, a method of neutralizing an acidic group with a lithium compound after polymerization, or performing ion substitution with lithium ions after neutralizing part or all of the acidic group with another neutralizing agent after polymerization. preferable.

  The combination of the radical polymerizable monomer having an acidic group and the radical polymerizable monomer having a hydrophobic group is preferably (meth) acrylic acid and lauryl (meth) acrylate, from the viewpoint of achieving both high conductivity and low viscosity. (Meth) acrylic acid and stearyl (meth) acrylate, maleic acid and diisobutylene, or maleic anhydride and diisobutylene, more preferably maleic acid and diisobutylene or maleic anhydride and diisobutylene.

  The anionic polymer dispersant is derived from a monomer other than the radical polymerizable monomer having an acidic group and the radical polymerizable monomer having a hydrophobic group (hereinafter referred to as other monomer) from the viewpoint of imparting a function according to the use. Although it may contain a structural unit, from the viewpoint of achieving both high conductivity and low viscosity, all the structural units of the anionic polymer dispersant are structural units derived from the radical polymerizable monomer having an acidic group, It is preferable that it consists only of structural units derived from the radical polymerizable monomer having a hydrophobic group.

  Examples of the other monomer include at least one selected from the monomers listed in the following (1) to (6).

(1) (meth) acrylamides,
(Meth) acrylamides are (meth) acrylamides in which hydrogen, alkyl groups, cycloalkyl groups, phenyl groups, benzyl groups, etc. are directly bonded to nitrogen atoms. Specifically, (meth) acrylamides, ethyl (Meth) acrylamide, isopropyl (meth) acrylamide, t-butyl (meth) acrylamide, dodecyl (meth) acrylamide, octadecyl (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dibutyl (meth) acrylamide, dimethyl Examples include aminoethyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide, with (meth) acrylamide and dimethyl (meth) acrylamide being preferred. These can be used alone or in admixture of two or more.

(2) Nonionic group-containing monomer,
Nonionic group-containing monomers include, for example, hydroxyalkyl (meth) acrylate, polyalkylene glycol ester (meth) acrylate, and polyalkylene glycol vinyl ether. Specifically, 2-hydroxyethyl (meth) acrylate, Examples include (meth) acrylic acid 3-hydroxypropyl and (meth) acrylic acid polyalkylene glycol monoester represented by the following chemical formula (1).
^{_{CH 2 = C (R 1)}} COO (R 2 O) p R 3 (1)
However, in the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent hydrocarbon group having up to 6 1 or more carbon atoms which may have a hetero atom, R ³ Represents a monovalent hydrocarbon group having 1 to 22 carbon atoms which may have a hetero atom, _p represents an average addition mole number, and is 1 or more and 100 or less, preferably 1 to 60. Among the nonionic group-containing monomers, 2-hydroxyethyl (meth) acrylate and (meth) acrylic acid polyalkylene glycol monoester represented by the following chemical formula (2) are preferable.
^{_{CH 2 = C (R 4)}} COO (R 5 O) p R 6 (2)
In the chemical formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an ethylene group or a propylene group, R ⁶ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms, _p Represents an average number of added moles, and is a number of 1 to 100, preferably 1 to 60. These nonionic group-containing monomers can be used alone or in admixture of two or more.

(3) Cationic monomer A cationic monomer is a monomer having an ammonium group in the molecule, and is a neutralized salt or quaternized product of dialkylaminoalkyl (meth) acrylate, diallyldimethylammonium salt, neutralized allylamine. And salts and quaternized compounds. Specifically, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate methyl halide quaternary, benzyl halide quaternized, diallyldimethylammonium halide, allyldimethylamine methyl halide quaternized, Examples thereof include benzyl halide quaternized compounds, and methyl chloride quaternized products of dimethylaminoethyl (meth) acrylate and diallyldimethylammonium chloride are preferable. These can be used alone or in admixture of two or more.

(4) Unsaturated nitriles Unsaturated nitriles are compounds having a carbon-carbon unsaturated bond and a nitrile group in one molecule, such as (meth) acrylonitrile, vinyl cyanoacetate, cyanoethyl (meth) acrylate, etc. (Meth) acrylonitrile is preferred.

  The anionic polymer dispersant of the present invention may have a crosslinked structure or a block structure. Therefore, you may have a structural unit derived from the following monomers (5) and (6) as said other monomer.

(5) Crosslinkable monomer The crosslinkable monomer is a compound having at least two carbon-carbon unsaturated bonds in one molecule, and preferably a divinyl compound, poly (meth) acrylic acid ester, bis (meth). Examples include acrylamide. Specific examples of the divinyl compound include divinylbenzene, divinyl adipate, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and polyethylene glycol divinyl ether, with divinyl benzene, diethylene glycol divinyl ether, and polyethylene glycol divinyl ether being preferred. Examples of poly (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylic acid, Di (meth) acrylic acid-1,5-pentanediol, di (meth) acrylic acid-1,6-hexanediol, di (meth) acrylic acid-1,4-phenylene, trimethylolpropane tri (meth) acrylate, Examples include pentaerythritol tetra (meth) acrylate, and polyethylene glycol di (meth) acrylate is preferable. Examples of bis (meth) acrylamide include bis (meth) acrylamide, methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, and hexamethylene bis (meth) acrylamide, with methylene bis (meth) acrylamide being preferred. These can be used alone or in admixture of two or more.

(6) Macromonomer A macromonomer is a reactive polymer in which a carbon-carbon unsaturated bond is added to one end of a polymer having a molecular weight of 1,000 to 100,000 by polymerizing a radical polymerizable monomer. A graft polymer can be obtained by copolymerization. Examples of the macromonomer include polystyrene macromer, poly (meth) acrylic ester macromer, and polysilicon macromer. Examples of the poly (meth) acrylate macromer include poly (meth) acrylate methyl macromer, poly (meth) butyl butyl macromer, and poly (meth) acrylate benzyl macromer. Among them, polystyrene macromer, poly (meth) acrylate methyl macromer, and poly (meth) acrylate benzyl macromer are preferable. The molecular weight of the polymer constituting the macromer is preferably 2000 or more, and more preferably 3000 or more. Moreover, 50000 or less is preferable, 20000 or less is more preferable, and 10,000 or less is still more preferable.

[Production method of anionic polymer dispersant]
The anionic polymer dispersant can be produced, for example, by the following method.

  When the total amount of raw material monomers used in the production of the anionic polymer dispersant is 100% by mass, the radical polymerizable monomer having the acidic group is contained in the total raw material monomers in an amount of 10% by mass to 90% by mass, and a hydrophobic group 10 to 70% by mass of a radical polymerizable monomer having

  The production of the anionic polymer dispersant is not particularly limited, but is preferably performed by the following precipitation polymerization method. In the precipitation polymerization method, polymerization is performed by dropping a mixture of an initiator and, if necessary, a monomer into the liquid while heating and stirring a liquid containing a solvent and a monomer mixture and, if necessary, a component such as a polymerization initiator. To do.

  As the polymerization initiator used in the polymerization, known radical polymerization initiators can be used. For example, azo polymerization initiators, hydroperoxides, dialkyl peroxides, diacyl peroxides, ketones Examples include peroxides and inorganic peroxides.

  The use amount of the polymerization initiator is preferably 0.01 mol or more and 5 mol or less, more preferably 0.01 or more and 3 mol or less, still more preferably 0.01 or more and 1 mol or less, when the total amount of raw material monomers is 100 mol. It is. The polymerization reaction is preferably performed in a temperature range of 30 to 180 ° C. under a nitrogen stream, and the reaction time is preferably 0.5 to 20 hours.

  In the polymerization, a chain transfer agent may be further added. Specific examples of the chain transfer agent include octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, mercaptoethanol, 3-mercapto-1,2-propanediol, mercaptopropionic acid, mercaptosuccinic acid and the like. Mercaptans; thiuram disulfides; unsaturated heterocyclic compounds, and the like. These may be used alone or in admixture of two or more.

  When the medium used for the polymerization is not an aqueous medium, it is preferable to perform solvent replacement or solvent removal after the polymerization. Moreover, even if it is an aqueous medium, you may perform solvent substitution or solvent removal for the purpose of refinement | purification or a change of a medium composition. As a method for solvent replacement and solvent removal, a method is generally used in which the solvent is distilled off by heating, reduced pressure or the like, or a solution after polymerization is dropped into a poor solvent of the copolymer to recover the precipitate.

  Part or all of the acidic groups of the polymer unneutralized product obtained by polymerization of the raw material monomer is neutralized by the addition of a lithium compound such as lithium hydroxide, and an aqueous solution or water dispersion of the anionic polymer dispersant A liquid (hereinafter sometimes abbreviated as an anionic polymer dispersant composition or simply a dispersant composition) is obtained.

  An example of a method for producing the dispersant composition is that a composition containing an unneutralized polymer and water is mixed with a neutralizer containing a lithium compound, and the weight average molecular weight is 5,000 or more and 100,000 or less. And a neutralization step of obtaining the anionic polymer dispersant composition in which 30 mol or more and 100 mol or less of the total number of acidic groups of the raw material monomer is neutralized by lithium ions.

  From the viewpoint of improving the yield of the dispersant composition, the solid content concentration of the polymer-containing non-neutralized product and water in the neutralization step is preferably 20% by mass or more, and 25% by mass or more. Is more preferable, and 30 mass% or more is still more preferable. Moreover, from a viewpoint of the stirrability improvement by suppression of thickening, 50 mass% or less is preferable, 45 mass% or less is more preferable, and 40 mass% or less is still more preferable.

  As the lithium compound, a compound that releases lithium ions in water is preferable, and lithium hydroxide, lithium alkoxide, lithium metal, lithium hydride, alkyl lithium, or lithium such as lithium nickelate, lithium cobaltate, or lithium manganate. Examples thereof include metal oxides or lithium phosphates such as lithium hexafluorophosphate and lithium iron phosphate. Among these, lithium hydroxide is preferable from the viewpoint of handling and efficient production of the lithium salt of the polymer.

  The amount of the lithium compound used in the neutralization step is preferably 30 mol or more with respect to 100 mol of acidic groups contained in the polymer non-neutralized product from the viewpoint of producing a dispersant composition having excellent dispersibility, and 40 mol or more. Is more preferable, 50 mol or more is further preferable, and 70 mol or more is further more preferable. In addition, from the viewpoint of producing a dispersant composition having excellent dispersibility, 150 mol or less is preferable, 130 mol or less is more preferable, and 110 mol or less is even more preferable.

  The lithium compound is preferably used as an aqueous solution from the viewpoint of easy handling. When a lithium compound is used as an aqueous solution, the mass ratio (lithium hydroxide / water) of the lithium compound to water in the aqueous solution is preferably 2/98 or more from the viewpoint of improving the yield of the dispersant composition and workability. 3/97 or more is more preferable, 5/95 or more is more preferable, and 8/92 or more is still more preferable.

  Furthermore, the neutralizing agent may contain components other than the lithium compound as long as the effects of the present invention are not impaired. The content of the lithium compound in the neutralizing agent is preferably 30% by mass or more, more preferably 50% by mass or more from the viewpoint of efficiently producing a dispersant composition and from the viewpoint of producing a dispersant composition having excellent dispersibility. Preferably, 70% by mass or more is further preferable, 90% by mass or more is even more preferable, and 100% by mass is particularly preferable.

  The method for mixing the composition containing the non-neutralized polymer and water and the neutralizing agent containing a lithium compound is not particularly limited. However, from the viewpoint of ease of production of the dispersant composition, the polymer The method of adding a neutralizing agent is preferable, stirring the composition containing an unneutralized material and water, and the method of adding gradually is still more preferable. When the neutralizer is added dropwise, the time required for the addition is preferably 0.5 hours or more from the viewpoint of suppressing aggregation of the polymer non-neutralized product and adhesion to the reaction vessel. Further, the time required for the dropping is preferably 3 hours or less from the viewpoint of efficiently producing a dispersant composition.

  The temperature of the composition containing the non-neutralized polymer and water in the neutralization step is preferably 20 ° C. or higher, preferably 40 ° C. or higher, from the viewpoint of uniformly progressing neutralization and improving the neutralization rate. Is more preferable. Moreover, from a viewpoint of suppressing evaporation of water, 90 degrees C or less is preferable, 85 degrees C or less is more preferable, and 80 degrees C or less is still more preferable.

  In the neutralization step of neutralizing some or all of the acidic groups of the polymer non-neutralized product obtained by polymerization of the raw material monomers, the polymer non-neutralized product aggregates to directly obtain a lithium salt. If difficult, the neutralization process can be carried out in two stages.

That is, an example of the method for producing the dispersant composition includes the following neutralization step 1 and neutralization step 2.
(Neutralization step 1): A composition containing a polymer obtained by polymerizing a raw material monomer containing a radical polymerizable monomer having an acidic group and a radical polymerizable monomer having a hydrophobic group and water, and in an amine type Step of mixing a first neutralizing agent containing a summing agent (neutralization step 2): mixing a mixture of the polymer and the first neutralizing agent with a second neutralizing agent containing a lithium compound The anionic polymer dispersion having a weight average molecular weight of 5,000 or more and 100,000 or less, and 30 moles or more and 100 moles or less when the number of moles of all acidic groups of the raw material monomer is 100 moles is neutralized by lithium ions. For obtaining an agent composition

[Neutralization step 1]
In the neutralization step 1, a composition containing a polymer non-neutralized product obtained by polymerizing raw material monomers and water and a first neutralizing agent containing an amine-based neutralizing agent are mixed. From the viewpoint of ease of neutralization, water may be mixed in advance with an unneutralized polymer.

  As the amine-based neutralizer, ammonia, monoethanolamine, diethanolamine, from the viewpoint of ease of handling, from the viewpoint of ease of production of the anionic polymer dispersant and from the viewpoint of producing a dispersant composition excellent in dispersibility, Triethanolamine, methyldiethanolamine, dimethylethanolamine and triisopropanolamine are preferred, ammonia and triethanolamine are more preferred, and ammonia is particularly preferred.

  The amount of the amine-based neutralizing agent used in the neutralization step 1 is selected from the viewpoints of suppressing aggregation of unneutralized polymers in the neutralization step and producing a dispersant composition having excellent dispersibility. The amount is preferably 0.5 mol or more, more preferably 1 mol or more, still more preferably 2 mol or more, and even more preferably 2.5 mol or more with respect to 100 mol of the acidic group contained in the non-neutralized product. Further, from the viewpoint of suppressing aggregation of the polymer non-neutralized product in the neutralization step and from the viewpoint of producing a dispersant composition having excellent dispersibility, 70 mol or less is preferable, 50 mol or less is more preferable, and 30 mol or less is still more preferable. .

  The amine-based neutralizing agent may be used as an aqueous solution. When the boiling point of the amine neutralizer is lower than 100 ° C., the amine neutralizer is preferably used as an aqueous solution from the viewpoint of ease of handling. When an amine-based neutralizer is used as an aqueous solution, the mass ratio of the amine-based neutralizer to water in the aqueous solution (amine-based neutralizer / water) is 10/10 from the viewpoint of improving the yield of the dispersant composition. 90 or more is preferable, and 20/80 or more is more preferable. Further, from the viewpoint of easy handling of the first neutralizing agent, 40/60 or less is preferable, and 30/70 or less is more preferable. In addition, it is preferable that the water which comprises aqueous solution is ion-exchange water.

  Although the mixing method of the composition containing a polymer non-neutralized product and water in the neutralization step 1 and the amine-based neutralizer is not particularly limited, from the viewpoint of ease of production of the dispersant composition, A method of adding an amine-based neutralizing agent while stirring a composition containing an unneutralized polymer and water is preferred. Further, the amine-based neutralizing agent may be added at once or gradually. The time from the addition of the amine-based neutralizing agent to the addition of the following lithium compound is preferably 5 minutes or more from the viewpoint of uniformly progressing neutralization and improving the neutralization rate. Moreover, 30 minutes or less is preferable from a viewpoint of manufacturing a dispersing agent composition efficiently.

  The temperature of the composition containing the polymer unneutralized product and water in the neutralization step 1 is preferably 50 ° C. or more, preferably 60 ° C. or more, from the viewpoint of uniformly proceeding neutralization and improving the neutralization rate. Is more preferable, and 70 ° C or higher is even more preferable. In addition, from the viewpoint of suppressing foaming of the composition containing the non-neutralized polymer and water and improving the stirrability, and from the viewpoint of suppressing volatilization of the first neutralizing agent and water evaporation, 90 ° C. The following is preferable, 85 ° C. or lower is more preferable, and 80 ° C. or lower is further preferable.

  From the viewpoint of improving the yield of the dispersant composition, the solid content concentration of the polymer-containing non-neutralized product and water in the neutralization step 1 is preferably 20% by mass or more, and 25% by mass or more. Is more preferable, and 30 mass% or more is still more preferable. Moreover, from a viewpoint of the stirrability improvement by suppression of thickening, 50 mass% or less is preferable, 45 mass% or less is more preferable, and 40 mass% or less is still more preferable.

[Neutralization step 2]
In the neutralization step 2, the mixture of the polymer non-neutralized product obtained in the neutralization step 1 and the amine-based neutralizer is mixed with a second neutralizer containing a lithium compound.

  The lithium compound is preferably a compound that releases lithium ions in water, and lithium metal oxide such as lithium hydroxide, metal lithium, lithium hydride, alkyl lithium, or lithium nickelate, lithium cobaltate, lithium manganate, etc. Alternatively, lithium phosphates such as lithium hexafluorophosphate and lithium iron phosphate can be used. Lithium hydroxide is preferable from the viewpoint of handling and efficient production of the lithium salt of the polymer.

  The amount of the lithium compound used in the neutralization step 2 is preferably 30 mol or more and 40 mol or more with respect to 100 mol of acidic groups contained in the polymer non-neutralized product from the viewpoint of producing a dispersant composition having excellent dispersibility. Is more preferable, 50 mol or more is further preferable, and 70 mol or more is further more preferable. Further, from the viewpoint of producing a dispersant composition having excellent dispersibility, 150 mol or less is preferable, 125 mol or less is more preferable, and 115 mol or less is even more preferable.

  The total amount of the amine-based neutralizer used in the neutralization step 1 and the amount of the lithium compound used in the neutralization step 2 is the viewpoint and dispersion of suppressing aggregation of the polymer non-neutralized product in the neutralization step From the viewpoint of producing a dispersant composition having excellent properties, the amount is preferably 30 mol or more, more preferably 40 mol or more, still more preferably 50 mol or more, and more preferably 70 mol or more with respect to 100 mol of acidic groups contained in the polymer unneutralized product. Even more preferred. Further, the total amount of the amine-based neutralizing agent used in the neutralizing step 1 and the amount of the lithium compound used in the neutralizing step 2 is based on the viewpoint of suppressing aggregation of the polymer unneutralized product in the neutralizing step. From the viewpoint of producing a dispersant composition having excellent properties and suppressing the odor derived from the amine-based neutralizer, it is preferably 150 mol or less, more preferably 130 mol or less, and even more preferably 110 mol or less.

  The lithium compound is preferably used as an aqueous solution from the viewpoint of easy handling. When a lithium compound is used as an aqueous solution, the mass ratio of the lithium compound to water (lithium compound / water) in the aqueous solution is preferably 2/98 or more from the viewpoint of improving the yield of the dispersant composition and workability. / 97 or more is more preferable, 5/95 or more is more preferable, and 8/92 or more is more preferable.

  Furthermore, the second neutralizing agent may contain components other than the lithium compound as long as the effects of the present invention are not impaired. The content of the lithium compound in the second neutralizing agent is preferably 30% by mass or more, and preferably 50% by mass or more from the viewpoint of efficiently producing a dispersant composition and from the viewpoint of producing a dispersant composition having excellent dispersibility. Is more preferable, 70 mass% or more is still more preferable, 90 mass% is still more preferable, and 100 mass% is especially preferable.

  The mixing method of the mixture obtained in the neutralization step 1 and the lithium compound in the neutralization step 2 is not particularly limited, but the mixture obtained in the neutralization step 1 from the viewpoint of ease of production of the dispersant composition. A method of adding an aqueous lithium compound solution to the mixture while stirring is preferable, and a method of adding dropwise is more preferable. The time for dropping the lithium compound aqueous solution is preferably 0.5 hours or more from the viewpoint of suppressing aggregation of the polymer non-neutralized product and adhesion to the reaction vessel. In addition, the time for dropping the lithium compound aqueous solution is preferably 3 hours or less from the viewpoint of efficiently producing the dispersant composition.

  The temperature of the mixture obtained in the neutralization step 1 in the neutralization step 2 is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, more preferably 70 ° C. from the viewpoint of uniformly progressing neutralization and improving the neutralization rate. The above is more preferable. Moreover, from the viewpoint of suppressing foaming of the mixture obtained in the neutralization step 1 and improving the stirring property and from the viewpoint of suppressing water evaporation, 90 ° C. or lower is preferable, 85 ° C. or lower is more preferable, and 80 ° C. or lower is preferable. Further preferred.

  Neutralization of some or all of the acidic groups of the polymer unneutralized product with a lithium compound may be performed before, during or after mixing with the carbon material, or before, during or after mixing. May be carried out in two or more stages, for example, neutralization of some of the acidic groups prior to mixing with the carbon material, and other parts of the acidic groups during mixing with the carbon material. Neutralization may be performed. From the viewpoint of achieving both high conductivity and low viscosity, neutralization of acidic groups is preferably performed before or during mixing with the carbon material, and more preferably performed before mixing. That is, in an example of the method for producing the aqueous conductive paste of the present invention, the radical polymerization of the carbon material and the raw material monomer having at least 10 mass% and 90 mass% of a radical polymerizable monomer having an acidic group and a hydrophobic group. A monomer containing 10% by mass or more and 70% by mass or less, 30 mol or more and 100 mol or less when the number of moles of all acidic groups is 100 mol, neutralized by lithium ions, and having a weight average molecular weight of 5,000 or more and 100,000 or less. A step of mixing an anionic polymer dispersant, which is a neutralized product of the molecule, and the aqueous medium; and the carbon material, an unneutralized product of the polymer, or one of the acidic groups. While mixing or after mixing the neutralized product of the polymer, the part of which is neutralized with lithium ions, and the aqueous medium, Therefore neutralized, it may include a step of obtaining a mixture containing the said carbon material and the anionic polymer dispersant wherein the aqueous medium.

[Aqueous medium]
The aqueous medium (component C) may contain an organic solvent that is uniformly mixed with water. However, the content of water in the aqueous medium (component C) is preferably from the viewpoint of achieving both high conductivity and low viscosity. Is 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably substantially 100% by mass, particularly preferably 100% by mass.

  Examples of the organic solvent uniformly mixed with water include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, 2-butanone, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, ethylene glycol, diethylene glycol, glycerin, N- Examples include methyl pyrrolidone or 2-pyrrolidone, and ethanol, 2-propanol, acetone, 2-butanone, or N-methylpyrrolidone is preferable.

[Aqueous conductive paste]
The content of the carbon material in the aqueous conductive paste of the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably from the viewpoint of achieving both high conductivity and low viscosity. It is 1% by mass or more, preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 20% by mass or less.

  The viscosity of the aqueous conductive paste of the present invention is preferably 1 mPa · s or more, more preferably 2 mPa · s, as measured with a rotational viscometer (25 ° C.) from the viewpoint of achieving both high conductivity and low viscosity. It is above, More preferably, it is 5 mPa * s or more, Preferably it is 1000000 mPa * s or less, More preferably, it is 100000 mPa * s or less, More preferably, it is 10,000 mPa * s or less.

  Moreover, as a standard for relatively evaluating the viscosity, for example, the viscosity of the aqueous conductive paste adjusted to contain 10% of the carbon material (component A) is preferably from the viewpoint of compatibility between high conductivity and low viscosity. Is 1 mPa · s or more, more preferably 2 mPa · s or more, still more preferably 5 mPa · s or more, preferably 1000 mPa · s or less, more preferably 500 mPa · s or less, still more preferably 200 mPa · s or less.

  The content of the dispersant composition in the aqueous conductive paste of the present invention is preferably 0.1 parts by mass or more, preferably 1 part by mass or more in terms of solid content of the dispersant composition with respect to 100 parts by mass of the carbon material. More preferred is 2 parts by mass or more. In addition, from the viewpoint of achieving both high conductivity and low viscosity, 100 parts by mass or less, preferably 50 parts by mass or less, more preferably 20 parts by mass or less in terms of solid content of the dispersant composition with respect to 100 parts by mass of the carbon material. More preferred are:

  The aqueous conductive paste of the present invention contains an inorganic filler, a binder resin, an active material, a viscosity modifier, other additives, and the like as necessary in addition to the carbon material, the dispersant, and the aqueous medium.

  The inorganic filler is not particularly limited as long as it does not greatly interfere with the compatibility of high conductivity and low viscosity. For example, in addition to silica, mica, metal oxide, metal halide, the carbon material Other carbon materials may be used.

  Examples of the binder resin include SBR resin, fluororesin, polyester resin, urethane resin, vinylidene fluoride resin, ethylene resin, and PET resin.

  Examples of the active material include lithium metal acid containing cobalt, nickel, manganese, and manganese oxide.

  The aqueous conductive paste of the present invention can be produced by a known dispersion method. Examples of the disperser used for dispersing components such as a carbon material include a kneader such as a roll mill, a kneader, and an extruder, a disper, a homomixer, a jet mill, a sand mill, a bead mill, a high-pressure homogenizer, and an ultrasonic homogenizer.

  The mixing order of each component is not particularly limited, and the carbon material, the dispersant composition, and the aqueous medium may be mixed together, or the dispersant composition is gradually added to the kneaded mixture of the carbon material and the aqueous medium. It may be a method. Moreover, the method of adding a dispersing agent composition and an aqueous medium separately with respect to a carbon material may be sufficient.

  The aqueous conductive paste of the present invention is excellent in coating property because the dispersibility of the carbon material is good, but the aqueous conductive paste of the present invention has better dispersibility of the carbon material than the conventional aqueous conductive paste. Due to the low viscosity, in some cases, coarse particles may be removed by filtering the paste obtained by mixing all or part of the aqueous conductive paste during the manufacturing process of the aqueous conductive paste. Is possible. Therefore, if the aqueous | water-based electrically conductive paste of this invention is used, much higher coating property will be attained, handling property and the manufacturing efficiency of an electrically conductive film will also improve.

  Coarse particles can be removed by, for example, passing the paste through a strainer, and the strainer opening is preferably 200 μm or less, more preferably 100 μm or less, from the viewpoint of improving coatability, and productivity is improved. From the viewpoint, it is preferably 10 μm or more, more preferably 30 μm or more.

  The present invention further discloses the following <1> to <28>.

<1> Contains a carbon material, a dispersant, an aqueous medium,
Of the carbon material, ash content of 1% by mass or less, volume resistivity 0.2Ωcm or less, the BET specific surface area of less 500 meters ² / g or more 2630 m ² / g,
The dispersant includes an anionic polymer dispersant,
The anionic polymer dispersant has at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group. A neutralized product of a polymer having a weight average molecular weight of 5,000 to 100,000 and having a weight average molecular weight of 5,000 to 100,000, wherein 30 to 100 moles are neutralized by lithium ions, Aqueous conductive paste.
<2> The weight average molecular weight of the anionic polymer dispersant is preferably 8000 or more, more preferably 10,000 or more, still more preferably 15000 or more, preferably 80000 or less, more preferably 60000 or less, and still more preferably 50000. The aqueous conductive paste according to <1>, wherein:
<3> The raw material monomer contains a radically polymerizable monomer having an acidic group, preferably 30% by mass or more, more preferably 45% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, The aqueous conductive paste according to <1> or <2>.
<4> The aqueous conductive paste according to any one of <1> to <3>, wherein the acidic group of the radical polymerizable monomer having an acidic group is a carboxylic acid group or a sulfonic acid group.
<5> The radical polymerizable monomer having an acidic group is at least one monomer selected from (meth) acrylic acid, maleic acid and maleic anhydride, according to any one of <1> to <4>. An aqueous conductive paste.
<6> The raw material monomer contains a radically polymerizable monomer having a hydrophobic group, preferably 20% by mass or more, more preferably 30% by mass or more, preferably 60% by mass or less, more preferably 55% by mass or less. The aqueous conductive paste according to any one of <1> to <5>.
<7> The radical polymerizable monomer having a hydrophobic group is preferably 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, styrene, isobutylene, It is at least one monomer selected from the group consisting of diisobutylene, 1-octadecene, and 1-eicosene, and more preferably selected from the group consisting of lauryl (meth) acrylate, stearyl (meth) acrylate, and diisobutylene. The aqueous conductive paste according to any one of <1> to <6>, wherein the aqueous conductive paste is at least one monomer selected from the group consisting of stearyl (meth) acrylate and diisobutylene. .
<8> Any of the above <1> to <7>, preferably 40 moles or more, more preferably 50 moles or more are neutralized with lithium ions when the number of moles of all acidic groups is 100 moles. The aqueous conductive paste described in 1.
<9> The combination of the radical polymerizable monomer having an acidic group and the radical polymerizable monomer having a hydrophobic group is preferably (meth) acrylic acid and lauryl (meth) acrylate, (meth) acrylic acid and (meth). Any of the above <1> to <8>, which is stearyl acrylate, maleic acid and diisobutylene, or maleic anhydride and diisobutylene, more preferably maleic acid and diisobutylene, or maleic anhydride and diisobutylene. The aqueous conductive paste described in 1.
<10> The aqueous conductive paste according to any one of <1> to <8>, wherein the anionic polymer dispersant is a lithium salt of a diisobutylene / maleic anhydride copolymer.
<11> The aqueous conductive paste according to any one of <1> to <8>, wherein the anionic polymer dispersant is a lithium salt of stearyl (meth) acrylate / (meth) acrylic acid copolymer. .
<12> The aqueous conductive paste according to any one of <1> to <11>, wherein the carbon material is ketjen black.
<13> The water content in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably substantially 100% by mass, particularly preferably. The aqueous conductive paste according to any one of <1> to <12>, which is 100% by mass.
<14>
The method for producing an aqueous conductive paste according to any one of <1> to <13>,
Ash content less than 1 wt%, the volume resistivity of 0.2Ωcm or less, BET specific surface area and less of the carbon material 500 meters ² / g or more 2630 m ² / g, the raw material monomers, a radical polymerizable monomer having at least an acidic group 10% to 90% by mass and 10% by mass to 70% by mass of a radically polymerizable monomer having a hydrophobic group, and 30 mol to 100 mol when the total number of acidic groups is 100 mol is lithium ion. A step of mixing the aqueous medium with an anionic polymer dispersant, which is a neutralized polymer having a weight average molecular weight of 5,000 to 100,000,
The carbon material, the polymer non-neutralized product or the polymer neutralized product in which a part of the acidic group is neutralized by lithium ions, and the aqueous medium are mixed or mixed. A method for producing an aqueous conductive paste, comprising a step of neutralizing the acidic group with lithium ions later to obtain a mixed liquid containing the carbon material, the anionic polymer dispersant, and the aqueous medium.
<15> The weight average molecular weight of the anionic polymer dispersant is preferably 8000 or more, more preferably 10,000 or more, further preferably 15000 or more, preferably 80000 or less, more preferably 60000 or less, and still more preferably 50000. The method for producing an aqueous conductive paste according to <14>, wherein:
<16> The raw material monomer contains a radical polymerizable monomer having an acidic group, preferably 30% by mass or more, more preferably 45% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, <14> or <15> The method for producing an aqueous conductive paste according to <15>.
<17> The method for producing an aqueous conductive paste according to any one of <14> to <16>, wherein the acidic group of the radical polymerizable monomer having an acidic group is a carboxylic acid group or a sulfonic acid group.
<18> The <14> to <17>, wherein the radical polymerizable monomer having an acidic group is at least one monomer selected from (meth) acrylic acid, maleic acid and maleic anhydride. A method for producing an aqueous conductive paste.
<19> The raw material monomer contains a radically polymerizable monomer having a hydrophobic group, preferably 20% by mass or more, more preferably 30% by mass or more, preferably 60% by mass or less, more preferably 55% by mass or less. The method for producing an aqueous conductive paste according to any one of <14> to <18>.
<20> The radical polymerizable monomer having a hydrophobic group is preferably 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, styrene, isobutylene, It is at least one monomer selected from the group consisting of diisobutylene, 1-octadecene, and 1-eicosene, and more preferably selected from the group consisting of lauryl (meth) acrylate, stearyl (meth) acrylate, and diisobutylene. The aqueous conductive paste according to any one of <14> to <19>, which is at least one monomer selected from the group consisting of stearyl (meth) acrylate and diisobutylene. Manufacturing method.
<21> Any of the above <14> to <20>, wherein 40 mol or more, more preferably 50 mol or more is neutralized with lithium ions when the total number of acidic groups is 100 mol The manufacturing method of aqueous | water-based electrically conductive paste as described in any one of.
<22> The combination of the radically polymerizable monomer having an acidic group and the radically polymerizable monomer having a hydrophobic group is preferably (meth) acrylic acid and lauryl (meth) acrylate, (meth) acrylic acid and (meth). Stearyl acrylate, maleic acid and diisobutylene, or maleic anhydride and diisobutylene, more preferably maleic acid and diisobutylene or maleic anhydride and diisobutylene, according to any one of <14> to <21> above The manufacturing method of aqueous conductive paste of description.
<23> The method for producing an aqueous conductive paste according to any one of <14> to <21>, wherein the anionic polymer dispersant is a lithium salt of a diisobutylene / maleic anhydride copolymer.
<24> The aqueous conductive paste according to any one of <14> to <21>, wherein the anionic polymer dispersant is a lithium salt of stearyl (meth) acrylate / (meth) acrylic acid copolymer. Manufacturing method.
<25> The method for producing an aqueous conductive paste according to any one of <14> to <24>, wherein the carbon material is ketjen black.
<26> The water content in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably substantially 100% by mass, particularly preferably. The manufacturing method of the aqueous | water-based electrically conductive paste in any one of said <14>-<25> which is 100 mass%.
<27> The polymer neutralized product is obtained by polymerizing the raw material monomer to obtain a polymer, and then neutralizing an acidic group of the polymer,
The neutralization of the acidic group is performed by mixing the composition containing the polymer and water with a first neutralizing agent containing an amine type neutralizing agent, and then mixing the composition and the first neutralizing agent. The method for producing an aqueous conductive paste according to any one of <14> to <26>, wherein the mixture is mixed with a second neutralizing agent containing a lithium compound.
<28> The above <14> to <27>, further comprising a step of passing a paste obtained by mixing the carbon material, the anionic polymer dispersant, and the aqueous medium through a strainer having an opening of 200 μm or less. The manufacturing method of the aqueous | water-based electrically conductive paste in any one of.

[Production Example 1 of Unneutralized Product of Anionic Polymer 1: Production of Unneutralized Product A of Anionic Polymer]
In a glass reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel, 621.8 g of diisobutylene (manufactured by Maruzen Petrochemical Co., Ltd.) and Rutonal A-50 (manufactured by BASF, polyvinyl ethyl ether) ) 3.1g was charged. The reaction vessel was filled with a nitrogen atmosphere and stirring was started. The reaction vessel contents were heated to 105 ° C., and thereafter, the temperature of the reaction vessel contents was maintained at 105 ° C. until the polymerization reaction was completed. 190.0 g of maleic anhydride in a molten state (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) kept at 70 ° C. and 23.1 g of diisobutylene and perbutyl O (manufactured by NOF Corporation, t-butylperoxy-2-ethylhexanoate) An initiator solution obtained by dissolving 10.3 g was dropped into a reaction vessel from another dropping funnel over 4 hours. Twenty minutes after the completion of the dropwise addition, 1.2 g of perbutyl O dissolved in 7.3 g of diisobutylene is added to the reaction vessel and further aged for 2 hours and 40 minutes to complete the polymerization reaction. A solution containing neutralized product A was obtained. In the reaction vessel, 800 g of ion-exchanged water was added to precipitate a precipitate of an anionic polymer non-neutralized product A. Subsequently, unreacted diisobutylene was distilled off by steam distillation. The steam distillation was performed until the reaction vessel was heated at normal pressure until the contents of the reaction vessel reached 100 ° C. and diisobutylene was not distilled. After removing water by decantation, the precipitate of the non-neutralized product A of the anionic polymer wetted with water was dried at 105 ° C. and 100 mmHg for 24 hours. Through the above operation, an anionic polymer non-neutralized product A (copolymerization ratio: diisobutylene / maleic anhydride = 53.4% by mass / 46.6% by mass) was obtained. The weight average molecular weight of the non-neutralized product A of the anionic polymer was 25000.

[Production Example 2 of Unneutralized Product of Anionic Polymer: Production of Unneutralized Product B of Anionic Polymer]
According to Production Example 1 of the non-neutralized product A of the anionic polymer except that an initiator solution obtained by dissolving 13.5 g of perbutyl O in 23.1 g of diisobutylene was used as the initiator solution. An unneutralized polymer B (copolymerization ratio: diisobutylene / maleic anhydride = 53.4 mass% / 46.6 mass%) was obtained. The weight average molecular weight of the non-neutralized product B of the anionic polymer was 12,000.

[Production Example 3 of Unneutralized Product of Anionic Polymer: Production of Unneutralized Product C of Anionic Polymer]
According to Production Example 1 of the non-neutralized product A of the anionic polymer except that an initiator solution obtained by dissolving 2.6 g of perbutyl O in 23.1 g of diisobutylene was used as the initiator solution. An unneutralized polymer C (copolymerization ratio: diisobutylene / maleic anhydride = 53.4% by mass / 46.6% by mass) was obtained. The weight average molecular weight of the non-neutralized product C of the anionic polymer was 97,000.

[Production Example 4 of Unneutralized Product of Anionic Polymer: Production of Unneutralized Product D of Anionic Polymer]
In a glass reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel, 74.7 g of 2-propanol (Mitsui Chemicals) was charged. The reaction vessel was filled with a nitrogen atmosphere and stirring was started. The reaction vessel contents were heated to 80 ° C., and thereafter the temperature of the reaction vessel contents was kept at 80 ° C. until the polymerization reaction was completed. In a dropping funnel, acrylic acid (made by Toa Gosei Co., Ltd.) 180.9 g, stearyl acrylate (made by Osaka Organic Chemical Industry Co., Ltd.) 89.1 g, 2,2′-azobis (isobutyric acid) dimethyl (V-601; Wako Pure Chemical Industries, Ltd.) (Manufactured by Kogyo Co., Ltd.) 1.44 g and 10-2.9 g of 2-propanol were charged and dropped into the reaction vessel over 4 hours. One hour after the completion of the dropwise addition, 0.72 g of V-601 and 6.5 g of 2-propanol were dropped from the dropping funnel into the reaction vessel over 30 minutes. Aging was performed for 6 hours from the end of the dropping, and 1060 g of ion-exchanged water was added for dilution. Next, after unreacted monomer and 2-propanol were distilled off by steam distillation, the solution was poured into a stainless steel square bat (bottom area of about 1200 cm ² ) covered with a fluororesin sheet at 105 ° C. and 100 mmHg for 48 hours. Dried. Through the above operation, an unneutralized product D (copolymerization ratio: stearyl acrylate / acrylic acid = 33.3% by mass / 66.7% by mass) of an anionic polymer was obtained. The weight average molecular weight of the non-neutralized product D of the anionic polymer was 15000.

[Production Example 1 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Composition A1]
The anionic polymer non-neutralized product A obtained in Production Example 1 was neutralized in the neutralization step shown below. 100 g of anionic polymer unneutralized product A and 100 g of water were charged into a reaction vessel and brought to 75 ° C. while stirring. Thereafter, the temperature of the liquid in the reaction vessel was kept at 75 ° C. until the neutralization reaction was completed. First, as a neutralization step 1, 3.3 g of a 25 mass% aqueous ammonia solution (manufactured by Showa Denko) was added to the reaction vessel and held for 15 minutes. Next, as neutralization step 2, 238 ml of 4N lithium hydroxide aqueous solution was dropped into the reaction vessel over 1.5 hours to complete the neutralization reaction. In order to volatilize the released ammonia, it is maintained for 3 hours under the condition of a reduced pressure of 47 kPa, returned to normal pressure, cooled to room temperature, ion-exchanged water is added so that the solid content becomes 25% by mass, and maintained for 30 minutes. Then, stirring was stopped to obtain an anionic polymer dispersant composition A1. The weight average molecular weight of the anionic polymer dispersant in the anionic polymer dispersant composition A1 was 25000.

[Production Examples 2 to 5 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Compositions A2 to 5]
Production of the anionic polymer dispersant composition A1 except that the amounts and types of the aqueous ammonia solution and the alkali metal hydroxide solution used in the neutralization step 1 and the neutralization step 2 are as described in Table 1. According to the examples, anionic polymer dispersant compositions A2 to A5 were obtained.

[Production Examples 6-7 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Compositions B1-2]
Instead of the non-neutralized product A of the anionic polymer, the unneutralized product B of the anionic polymer obtained in Production Example 2 was used, and the aqueous ammonia solution and alkali metal hydroxide used in the neutralization steps 1 and 2 were used. Anionic polymer dispersant compositions B1 and B2 were obtained according to the production examples of the anionic polymer dispersant composition A1 except that the amount and type of the aqueous solution of the product were as described in Table 1.

[Production Examples 8-9 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Composition C1-2]
Instead of the non-neutralized product A of the anionic polymer, the non-neutralized product C of the anionic polymer obtained in Production Example 3 was used, and the aqueous ammonia solution and alkali metal hydroxide used in the neutralization steps 1 and 2 were used. Anionic polymer dispersant compositions C1 and C2 were obtained in accordance with the production examples of the anionic polymer dispersant composition A1 except that the amount and type of the aqueous solution of the product were as described in Table 1.

[Production Example 10 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Composition D1]
The non-neutralized product D of the anionic polymer obtained in Production Example 4 was neutralized in the neutralization step shown below. 50 g of non-neutralized product D of anionic polymer D and 450 g of water were charged in a reaction vessel and stirred at 25 ° C. As a neutralization step, 117 ml of 4N lithium hydroxide aqueous solution was dropped into the reaction vessel over 1 hour to complete the neutralization reaction. Ion exchange water was added so that the solid content would be 8% by mass, and after maintaining for 30 minutes, stirring was stopped to obtain an anionic polymer dispersant composition D1. The weight average molecular weight of the anionic polymer dispersant in the anionic polymer dispersant composition D1 was 15000.

[Production Examples 11-12 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Composition D2-3]
According to the production example of the anionic polymer dispersant composition D1, except that the alkali metal hydroxide aqueous solution used in the neutralization step has the contents shown in Table 1, the anionic polymer dispersant composition D2 3 was obtained.

[Production Example 13 of Anionic Polymer Dispersant Composition: Production of Anionic Polymer Dispersant Composition E1]
Commercially available polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd .; polyacrylic acid 5,000) was neutralized in the neutralization step shown below. A reaction vessel was charged with 100 g of polyacrylic acid and 200 g of water, and stirred at 25 ° C. In the neutralization step, 347 ml of 4N lithium hydroxide aqueous solution was dropped into the reaction vessel over 1 hour to complete the neutralization reaction. Ion exchange water was added so that the solid content would be 10% by mass, and after maintaining for 30 minutes, stirring was stopped to obtain an anionic polymer dispersant composition E1.

[Weight average molecular weight measurement of non-neutralized anionic polymer and anionic polymer dispersant]
The weight average molecular weights of the non-neutralized anionic polymer and the anionic polymer dispersant were measured by GPC (gel permeation chromatography) under the following conditions. The weight average molecular weight was calculated based on a calibration curve prepared in advance. The following standard samples were used for preparing the calibration curve.
Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: TSK α-M + α-M (both manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Detector: RI
Eluent: N, N-dimethylformamide solution added with H ₃ PO ₄ (60 mmol / L) and LiBr (50 mmol / L) Flow rate: 1.0 mL / min
Sample concentration: 0.1% by mass (solid content)
Sample injection volume: 0.1 mL
Standard samples: polystyrene manufactured by Tosoh Corporation 5.26 × 10 ² , 1.02 × 10 ⁵ , 8.42 × 10 ⁶ ; polystyrene manufactured by Nishio Kogyo Co., Ltd. 4.0 × 10 ³ , 3.0 × 10 ⁴ , 9.0 × 10 ⁵ (Numbers are each molecular weight)

[Measurement of solid content in composition]
The solid content in each composition was measured by the following method. A sample 1 g was taken in a petri dish having a mass of W3 (g), and the mass of the entire petri dish including the sample was measured to obtain W1 (g). The entire petri dish was dried at 170 ° C. for 2 hours with a hot air circulating dryer (Hot Air Rapid Drying Soyokaze manufactured by Isuzu Seisakusho), and further allowed to cool for 30 minutes with a desiccator, and then the petri dish containing the non-volatile content of the sample was collected. The total mass was measured and designated as W2 (g). The value obtained from the following formula was defined as the solid content.
Solid content (% by mass) = 100− (W1−W2) / (W1−W3) × 100

[Production Example 1 of aqueous conductive paste 1: Production of aqueous conductive paste 1]
In a 100 mL poly wide mouth bottle (Nikko Hansen), as a carbon material, an ash content of 0.1% by mass, a BET specific surface area of 800 m ² / g, a volume resistivity value of 0.10 Ω-cm at a load of 120 kg / cm ² Ketjen Black (trade name EC300J powder, manufactured by Ketjen Black International Co., Ltd.) 4 g, anionic polymer dispersant composition A1 1.6 g as a dispersant composition, and a total amount of ion-exchanged water 40 g as an aqueous medium Then, 80 g of 1 mmφ zirconia beads (manufactured by Nikkato Co., Ltd.) were charged, the container was sealed, and dispersed for 3 hours with a paint shaker (manufactured by Asada Tekko Co., Ltd.). From the obtained paste, zirconia beads were removed with a 30-mesh (about 600 μm) stainless steel wire mesh to obtain an aqueous conductive paste 1.

[Production Examples 2 to 16 of aqueous conductive paste: Production of aqueous conductive paste 2 to 16]
The composition of the carbon material, the dispersant composition, and the aqueous medium was changed to the contents shown in Table 2, and aqueous conductive pastes 2 to 16 were obtained according to the production example of the aqueous conductive paste 1. The ash content of acetylene black (trade name Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) used for the production of the aqueous conductive paste 11 is 0.05% by mass, the BET specific surface area is 76 m ² / g, and the volume is specific at a load of 120 kg / cm ² . The resistance value is 0.17 Ω-cm.

[Production Example 17 of aqueous conductive paste: Production of aqueous conductive paste 17]
100 g of anionic polymer non-neutralized product A obtained in Production Example 1 and 100 g of water were charged into a reaction vessel and stirred at 75 ° C., and as a neutralization step 1, 33 g of 25% by mass aqueous ammonia solution was placed in the reaction vessel. In addition, held for 30 minutes. The mixture was cooled to room temperature while stirring. 0.93 g of the resulting suspension, 4 g of ketjen black, 0.95 ml of 4N lithium hydroxide aqueous solution were charged into a 100 ml poly wide-mouth bottle, and ion-exchanged water was added so that the total amount became 40 g, and 1 mmφ zirconia beads 80 g After the container was sealed, the container was sealed and dispersed for 3 hours with a paint shaker. From the obtained paste, zirconia beads were removed with a 30-mesh stainless steel wire mesh to obtain an aqueous conductive paste 17. The composition in the aqueous conductive paste 17 is 10% ketjen black and 1% dispersant, and the acidic groups neutralized by lithium ions are 100 when the total number of acidic groups in the dispersant is 100 mol. Is a mole.

[Ratio of acidic groups neutralized by lithium ions (counter ions) when the number of moles of all acidic groups is 100 mol (mol%)]
For a polymer in which some of the total acidic groups are neutralized, the total acid group present in the polymer is A (mole) and the amount of lithium ions present in the system is B (mole). Thus, the ratio of acidic groups neutralized by lithium ions was obtained.
B / A × 100 (mol%)
When all the acidic groups are all neutralized and the same or excessive amount of cations as the total acidic groups are present in the system, and when some or all of the total cations are lithium, the total cations Assuming that all acidic groups are neutralized by the proportion of lithium ions in the total, the amount of total cations is C (mol), the amount of lithium ions is D (mol), A proportion of neutralized acidic groups was obtained.
D / C x 100 (mol%)
The amount of ions in the aqueous conductive paste can be measured by a method such as potentiometric titration. The amount and ratio of alkali metals and the like can be measured after separating the solid and liquid by adding a strong acid to the aqueous conductive paste. It can be measured by quantifying the liquid phase by elemental analysis or the like.

[Measurement of filterability]
Using a filter holder KGS-25 for vacuum filtration manufactured by ADVANTEC with a 200-mesh (mesh size of about 75 μm) stainless steel wire mesh installed on a 100-mesh stainless support screen, 10 g of the obtained aqueous conductive paste was reduced in pressure. Was set to 60 kPa, and the filtration time and the amount of residue on the wire mesh were measured. A filtration time of 1 minute or less and almost no residue on the wire mesh was determined as good (A), and the others were determined as poor (C).

[Measurement of dispersibility]
The average particle size / nm of the powder in the aqueous conductive paste was measured using a particle size measuring instrument (Metavern Zetasizer Nano-S). The smaller the average particle size, the better the dispersibility. A glass cubette cell was used for measurement, and a sample collected for measurement was diluted with ion-exchanged water to such an extent that light was transmitted in advance, and immediately measured, and dispersibility was evaluated according to the following evaluation criteria. In addition, the parameter at the time of measurement used the numerical value (refractive index 1.800, absorption 10.000) of the carbon black published in the data attached to an apparatus. In this evaluation standard, A and B have good dispersibility.
<Evaluation criteria for dispersibility>
A: 300 nm or less B: Over 300 nm and 1000 nm or less C: Over 1000 nm

[Measurement of viscosity]
About the obtained aqueous conductive paste, the viscosity at 25 ° C. was measured using a measurement plate CPE-52 with an E-type viscometer (manufactured by BROOKFIELD; DV-II + Pro), and the aqueous conductive paste was measured according to the following evaluation criteria. The viscosity was evaluated. In this evaluation standard, A and B have good viscosity.
A: 200 mPa · s or less B: Over 200 mPa · s to 1000 mPa · s or less C: Over 1000 mPa · s

[Measurement of coatability]
The obtained aqueous conductive paste was applied using a grindometer (manufactured by Yasuda Seiki Seisakusho; No. 527, measurable range: 0-25 μm), and the particle size at the time of streaking / μm (that is, the size of coarse particles) Measured). The smaller the particle size at the time of streaking, the smaller the coarse particles and the better the coatability. The coatability was evaluated according to the following evaluation criteria. In this evaluation standard, A and B have good coatability.
A: 10 μm or less B: Over 10 μm and 25 μm or less C: Over 25 μm

[Measurement of conductivity]
The obtained aqueous conductive paste and fluororesin emulsion (Daikin Industries, Ltd. POLYFLON D-1E) were blended so that the amount of carbon material / the amount of fluororesin resin (solid content) = 8/2. It apply | coated to 100-micrometer PET biaxially stretched film using a 100-micrometer applicator. After the obtained coating film was dried at 100 ° C. for 10 minutes, the volume resistance was measured in a room adjusted to a temperature of 25 ° C. and a relative humidity of 50% based on JIS K 7194. In addition, volume resistance shows that it is excellent in electroconductivity, so that a numerical value is small. Conductivity was evaluated according to the following evaluation criteria. In this evaluation standard, A and B have good conductivity.
A: 10 Ωcm or less B: Over 10 Ωcm to 100 Ωcm or less C: Over 100 Ωcm

[Measurement result]
With respect to the aqueous conductive pastes 1 to 16, the above-mentioned [Measurement of filterability], [Measurement of dispersibility], [Measurement of viscosity], [Measurement of coatability], and [Measurement of conductivity] were performed. The results are shown in Table 2.

  As shown in Table 2, when the aqueous conductive paste of the example was used, better filterability, high dispersibility, low viscosity, and superior than when the aqueous conductive paste of the comparative example was used. Both coatability and high conductivity can be achieved.

  Since the aqueous conductive paste of the present invention has both high conductivity and low viscosity, if the aqueous conductive paste of the present invention is used, a conductive film having high conductivity and good coatability can be formed. . Therefore, the aqueous conductive paste of the present invention is particularly suitable as a conductive paste for batteries and electrodes and a conductive paste for conductive resins.

Claims (9)

Contains carbon material, dispersant, aqueous medium,
The carbon material, ash content is less than 1% or less, the volume resistivity of 0.2Ωcm or less, BET specific surface area is less than 500 meters ² / g or more 2630 m ² / g,
The dispersant includes an anionic polymer dispersant,
The anionic polymer dispersant has at least 10% by mass to 90% by mass of a radical polymerizable monomer having an acidic group and 10% by mass to 70% by mass of a radical polymerizable monomer having a hydrophobic group. A neutralized product of a polymer having a weight average molecular weight of 5,000 to 100,000 and having a weight average molecular weight of 5,000 to 100,000, wherein 30 to 100 moles are neutralized by lithium ions, Aqueous conductive paste.   The aqueous conductive paste according to claim 1, wherein the radically polymerizable monomer having an acidic group is at least one monomer selected from (meth) acrylic acid, maleic acid and maleic anhydride.   3. The aqueous conductive paste according to claim 1, wherein the radical polymerizable monomer having a hydrophobic group is at least one monomer selected from stearyl (meth) acrylate and diisobutylene.   The aqueous conductive paste according to any one of claims 1 to 3, wherein the anionic polymer dispersant is a lithium salt of a diisobutylene / maleic anhydride copolymer.   The aqueous conductive paste according to any one of claims 1 to 3, wherein the anionic polymer dispersant is a lithium salt of stearyl (meth) acrylate / (meth) acrylic acid copolymer.   The aqueous conductive paste according to any one of claims 1 to 5, wherein the carbon material is ketjen black. A method for producing an aqueous conductive paste according to any one of claims 1 to 6,
Ash content less than 1 wt%, the volume resistivity of 0.2Ωcm or less, BET specific surface area and less of the carbon material 500 meters ² / g or more 2630 m ² / g, the raw material monomers, a radical polymerizable monomer having at least an acidic group 10% to 90% by mass and 10% by mass to 70% by mass of a radically polymerizable monomer having a hydrophobic group, and 30 mol to 100 mol when the total number of acidic groups is 100 mol is lithium ion. A step of mixing the aqueous medium with an anionic polymer dispersant, which is a neutralized polymer having a weight average molecular weight of 5,000 to 100,000,
The carbon material, the polymer non-neutralized product or the polymer neutralized product in which a part of the acidic group is neutralized by lithium ions, and the aqueous medium are mixed or mixed. A method for producing an aqueous conductive paste, comprising a step of neutralizing the acidic group with lithium ions later to obtain a mixed liquid containing the carbon material, the anionic polymer dispersant, and the aqueous medium. The neutralized product of the polymer is obtained by polymerizing the raw material monomer to obtain a polymer, and then neutralizing an acidic group of the polymer,
The neutralization of the acidic group is performed by mixing the composition containing the polymer and water with a first neutralizing agent containing an amine type neutralizing agent, and then mixing the composition and the first neutralizing agent. The manufacturing method of the aqueous | water-based electrically conductive paste of Claim 7 performed by mixing the 2nd neutralizing agent containing a lithium compound with the mixture.   The aqueous conductive according to claim 7 or 8, further comprising a step of passing a paste obtained by mixing the carbon material, the anionic polymer dispersant, and the aqueous medium through a strainer having an opening of 200 µm or less. Manufacturing method of paste.