JP7131941B2 - Method for producing dispersion containing conjugated conductive polymer, method for producing solid electrolytic capacitor, and solid electrolytic capacitor - Google Patents

Description

The present invention relates to a solid electrolytic capacitor manufacturing method and a solid electrolytic capacitor obtained by the manufacturing method.

A solid electrolytic capacitor has been proposed that is manufactured by forming a dielectric oxide film on a metal surface by anodization and bringing it into contact with a solid electrolyte, and using a conductive polymer as the solid electrolyte.

Aluminum, tantalum, niobium, etc. are known as examples of metals covered with a dielectric oxide film by anodization.
Conjugated conductive polymers such as polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene, poly(p-phenylene-vinylene), polyacene, polythiophene vinylene and derivatives thereof are known as conductive polymers used in solid electrolytic capacitors. It is Also known is a technique of doping the conjugated conductive polymer with a polyanion such as polystyrenesulfonic acid as a counter anion of the conjugated conductive polymer.

A solid electrolyte is generally formed by chemical oxidation polymerization of a monomer compound solution and an oxidizing agent solution on a dielectric oxide film formed on a metal surface having a valve action, or by electrolytic polymerization. A method of forming by coating an aqueous solution or suspension of a conductive polymer has also been proposed.

For example, Patent Document 1 discloses a step of forming a first solid electrolyte layer by impregnating a capacitor element with a conductive polymer-dispersed aqueous solution in which fine particles of a conductive polymer are dispersed, and forming the first solid electrolyte layer. A second solid electrolyte by impregnating the surface of with a solution containing a heterocyclic monomer and a solution containing an oxidizing agent individually or with a mixed solution containing a heterocyclic monomer and an oxidizing agent A manufacturing method is disclosed comprising the step of forming a layer.

In Patent Document 2, a conductive polymer layer is formed as a solid electrolyte layer by chemically polymerizing a polymerizable monomer on a capacitor element in which a dielectric oxide film is formed on the surface of a sintered body obtained by sintering valve metal powder. After that, the capacitor element is immersed in a conductive polymer solution or coated with a conductive polymer solution and dried to form a thicker conductive polymer layer on the conductive polymer layer formed by chemical polymerization. A method is disclosed.

In Patent Document 3, in order to impregnate the inside of the capacitor with a conductive polymer, the viscosity of a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT-PSS) dispersion is reduced and ultrasonic irradiation is used. have been proposed to polymerize

In Patent Document 4, a capacitor is produced by polymerizing a monomer compound in a dispersion medium containing seed particles that have been made into a protective colloid by a monomer compound and a polyanion to obtain a dispersion containing a conjugated conductive polymer. A method and a solid electrolytic capacitor capable of manufacturing a solid electrolytic capacitor having excellent characteristics with good productivity are presented. This solid electrolytic capacitor is characterized by low equivalent series resistance (ESR), excellent frequency characteristics, and little characteristic change with respect to temperature change by using a conductive polymer.

JP 2003-100561 A JP 2005-109252 A Japanese Patent Publication No. 2011-510141 WO2014/163202

However, these prior art techniques have room for further improvement in capacity development ratio (capacitance) and equivalent series resistance (ESR) performance.
SUMMARY OF THE INVENTION An object of the present invention is to provide a solid electrolytic capacitor having a high capacity development rate (capacitance) and a low equivalent series resistance (ESR), and a method for manufacturing the same.

As a result of intensive research, the present inventors have found that a complex formed by a conjugated conductive polymer and a polyanion is solved in the process of producing a conjugated conductive polymer dispersion used as a solid electrolyte for a solid electrolytic capacitor. The inventors have found that the above problems can be solved by adding a salt compound to a dispersion containing these in order to efficiently coagulate, and have completed the present invention.

That is, the present invention relates to a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor according to the following [1] to [14].
[1]
A method for manufacturing a solid electrolytic capacitor having a porous anode body made of a valve metal having a dielectric coating on its surface and a solid electrolyte layer provided on the surface of the dielectric coating, comprising:
Polymerizing a monomer compound for obtaining a conjugated conductive polymer in a liquid containing a polyanion and an aqueous medium to obtain a dispersion (1) containing the conjugated conductive polymer, and a step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion (2) containing the conjugated conductive polymer;
a step (B) of attaching the dispersion (2) to a porous anode body made of a valve action metal having a dielectric coating on the surface; Step (C) of removing the medium and forming a solid electrolyte layer
has
A method for producing a solid electrolytic capacitor, wherein in the step (A), a salt compound is added to the dispersion (1) or to the aqueous medium in the process of obtaining the dispersion (1).

[2]
The method for manufacturing a solid electrolytic capacitor according to [1] above, wherein seed particles that have been converted into a protective colloid with a polyanion are dispersed in the aqueous medium.

[3]
The method for producing a solid electrolytic capacitor according to [1] or [2] above, wherein the amount of the salt compound added is 0.01 to 30 mass % of the amount of the dispersion (2).

[4]
The method for producing a solid electrolytic capacitor according to any one of [1] to [3], wherein the salt compound is at least one selected from organic acid salts and inorganic acid salts.

[5]
The salt compound is citrate, lactate, glycolate, gluconate, acetate, propionate, fumarate, oxalate, tartrate, hydrochloride, carbonate, bicarbonate, sulfate The method for producing a solid electrolytic capacitor according to any one of [1] to [4], wherein the solid electrolytic capacitor is at least one selected from the group consisting of salts, hydrogen phosphates, and phosphates.

[6]
The method for producing a solid electrolytic capacitor according to any one of [1] to [5], wherein in the step (A), a salt compound is added to the dispersion (1).

[7]
Any one of the above [1] to [6], wherein the viscosity of the dispersion liquid (1) immediately after adding the salt compound is 1.05 to 100.0 times the viscosity immediately before adding the salt compound. and a method for manufacturing a solid electrolytic capacitor.

[8]
The method for producing a solid electrolytic capacitor according to any one of [2] to [7], wherein the seed particles are polymer particles of ethylenically unsaturated monomers.

[9]
The method for producing a solid electrolytic capacitor according to any one of [2] to [8] above, wherein the seed particles converted into protective colloid with the polyanion have a d50 particle size of 0.01 to 10 μm.

[10]
The method for producing a solid electrolytic capacitor according to any one of [1] to [9], wherein the monomer compound is at least one selected from the group consisting of pyrrole compounds, aniline compounds, and thiophene compounds.

[11]
The monomer compound is represented by the following formula (1)

（式中、Ｒ¹及びＲ²は、各々独立して水素原子、水酸基、置換基を有してもよい炭素数１～１８のアルキル基、置換基を有してもよい炭素数１～１８のアルコキシ基、若しくは置換基を有してもよい炭素数１～１８のアルキルチオ基を表し、または
Ｒ¹及びＲ²は、Ｒ¹とＲとが互いに結合して、置換基を有してもよい炭素数３～１０の脂環、置換基を有してもよい炭素数６～１０の芳香環、置換基を有してもよい炭素数２～１０の酸素原子含有複素環、置換基を有してもよい炭素数２～１０のイオウ原子含有複素環、若しくは置換基を有してもよい炭素数２～１０のイオウ原子及び酸素原子含有複素環を表す。）
で示される化合物である前記［１］～［１０］のいずれかの固体電解コンデンサの製造方法。

(wherein R ¹ and R ² are each independently a hydrogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 18 carbon atoms, an optionally substituted C 1 to 18 or ^an optionally substituted ^alkylthio group having ¹ to 18 carbon atoms, or an alicyclic ring having 3 to 10 carbon atoms which may be substituted, an aromatic ring having 6 to 10 carbon atoms which may have a substituent, an oxygen atom-containing heterocyclic ring which may have a substituent and having 2 to 10 carbon atoms, and a substituent represents an optionally substituted sulfur atom-containing heterocyclic ring having 2 to 10 carbon atoms, or an optionally substituted carbon atom-containing heterocyclic ring containing 2 to 10 carbon atoms and an oxygen atom.)
The method for producing a solid electrolytic capacitor according to any one of [1] to [10], which is a compound represented by

[12]
The method for producing a solid electrolytic capacitor according to any one of the above [1] to [11], wherein the polyanion is a polymer having at least one of a sulfo group and a group consisting of a salt of the sulfo group.

[13]
Any one of the above [1] to [12], wherein the polyanion is used in an amount such that the proportion of anionic groups in the polyanion is 0.25 to 30.00 mol per 1 mol of the monomer compound. A method for manufacturing a solid electrolytic capacitor.

[14]
A solid electrolytic capacitor obtained by the manufacturing method according to any one of [1] to [13].

According to the method for manufacturing a solid electrolytic capacitor of the present invention, a solid electrolytic capacitor having a high capacity expression rate (electrostatic capacitance) and a low equivalent series resistance (ESR) can be manufactured.
The solid electrolytic capacitor of the present invention has a high capacity expression rate (capacitance) and a low equivalent series resistance (ESR).

FIG. 1 shows an outline of step (A) in Examples and the like.

The manufacturing method of the solid electrolytic capacitor of the present invention comprises:
A method for manufacturing a solid electrolytic capacitor having a porous anode body made of a valve metal having a dielectric coating on its surface and a solid electrolyte layer provided on the surface of the dielectric coating, comprising:
Polymerizing a monomer compound for obtaining a conjugated conductive polymer in a liquid containing a polyanion and an aqueous medium to obtain a dispersion (1) containing the conjugated conductive polymer, and a step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion (2) containing the conjugated conductive polymer;
a step (B) of attaching the dispersion (2) to a porous anode body made of a valve action metal having a dielectric coating on the surface; Step (C) of removing the medium and forming a solid electrolyte layer
has
In the step (A), a salt compound is added to the dispersion (1) or to the aqueous medium on the way to obtain the dispersion (1).

In the present specification, a polymer obtained by polymerizing a single monomer compound for obtaining a conjugated conductive polymer, and a copolymer obtained by copolymerizing a plurality of the monomer compounds. The polymer is collectively called a "conjugated conductive polymer".

In the present specification, a particle in which a polyanion is coordinated on the surface of the seed particle to form a protective colloid is referred to as a "seed particle formed into a protective colloid by a polyanion". In addition, a polyanion means the polymer which has two or more anionic groups.
As used herein, "(meth)acrylic" means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate.

<Step (A) of obtaining a dispersion liquid (2) containing a conjugated conductive polymer>
(Preparation of dispersion liquid (1) containing conjugated conductive polymer)
The step of obtaining dispersion liquid (1) containing a conjugated conductive polymer is carried out by polymerizing the above monomer compound in a liquid containing a polyanion and an aqueous medium. As a more specific embodiment of this liquid,
(i) a liquid containing a monomeric compound, a polyanion and an aqueous medium; and (ii) a liquid containing a monomeric compound, a polyanion protective colloidalized seed particles and an aqueous medium. The liquid (ii) may further contain a polyanion (a polyanion added separately from the polyanion used for protective colloidalization of the seed particles; hereinafter sometimes referred to as "free polyanion").

Dispersion liquid (1) containing a conjugated conductive polymer is composed of a complex of a conjugated conductive polymer and a polyanion, and a complex of a conjugated conductive polymer and a seed particle made into a protective colloid by the polyanion. At least one selected complex is a dispersion in an aqueous medium. In this step, the polyanion is considered to form a complex by being doped into the conjugated conductive polymer.

[Monomer compound]
A monomer compound that induces a structural unit of the conjugated conductive polymer includes a pyrrole compound (that is, pyrrole that may have a substituent), an aniline compound (that is, aniline that may have a substituent). , and thiophene compounds (that is, thiophenes which may have a substituent). Examples of substituents include alkyl groups having 1 to 18 carbon atoms, aryl groups having 6 to 10 carbon atoms, heteroaryl groups having 5 to 10 carbon atoms, alkoxy groups having 1 to 18 carbon atoms, and alkylthio groups having 1 to 18 carbon atoms. groups, carboxy groups, hydroxyl groups, halogen atoms and cyano groups. The alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with one or more selected from a carboxy group, a hydroxyl group, a halogen atom and a cyano group. Also, two or more of the substituents may be condensed to form a ring.

Specific examples of the monomer compounds include pyrrole, N-methylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, and 3-octylpyrrole, which are pyrrole compounds. , 3-decylpyrrole, 3-dodecylpyrrole, 3,4-dimethylpyrrole, 3,4-dibutylpyrrole, 3-carboxypyrrole, 3-methyl-4-carboxylpyrrole, 3-methyl-4-carboxyethylpyrrole, 3 -methyl-4-carboxybutylpyrrole, 3-hydroxypyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-butoxypyrrole, 3-hexyloxypyrrole, 3-methyl-4-hexyloxypyrrole, 3-methyl-4 - hexyloxypyrrole;
aniline, 2-methylaniline, 3-isobutylaniline, 2-anilinesulfonic acid, and 3-anilinesulfonic acid, which are the aniline compounds;
The thiophene compounds, thiophene, 3-methylthiophene, 3-ethylthiophene, 3-propylthiophene, 3-butylthiophene, 3-hexylthiophene, 3-heptylthiophene, 3-octylthiophene, 3-decylthiophene, 3- dodecylthiophene, 3-octadecylthiophene, 3-bromothiophene, 3-chlorothiophene, 3-iodothiophene, 3-cyanothiophene, 3-phenylthiophene, 3,4-dimethylthiophene, 3,4-dibutylthiophene, 3-hydroxy Thiophene, 3-methoxythiophene, 3-ethoxythiophene, 3-butoxythiophene, 3-hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene, 3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyl oxythiophene, 3,4-dihydroxythiophene, 3,4-dimethoxythiophene, 3,4-diethoxythiophene, 3,4-dipropoxythiophene, 3,4-dibutoxythiophene, 3,4-dihexyloxythiophene, 3 ,4-diheptyloxythiophene, 3,4-dioctyloxythiophene, 3,4-didecyloxythiophene, 3,4-didodecyloxythiophene, 3,4-ethylenedioxythiophene, 3,4-propylenedioxy Thiophene, 3,4-butylenedioxythiophene, 3-methyl-4-methoxythiophene, 3-methyl-4-ethoxythiophene, 3-carboxythiophene, 3-methyl-4-carboxythiophene, 3-methyl-4-carboxy ethylthiophene, 3-methyl-4-carboxybutylthiophene, 3,4-ethyleneoxythiathiophene;
is mentioned.

The monomer compounds may be used singly or in combination of two or more.
Among the above compounds, pyrrole, N-methylpyrrole, thiophene, 3-methylthiophene, 3-methoxythiophene and 3,4-ethylenedioxythiophene are preferable from the viewpoint of obtaining a conjugated conductive polymer having high conductivity. .

Among the above compounds, the monomer compound preferably contains a compound represented by the following formula (1), more preferably a compound represented by the following formula (2). More preferably, ethylenedioxythiophene is included.

In the above formula (1), R ¹ and R ² each independently represent a hydrogen atom, a hydroxyl group, or the number of carbon atoms which may have a substituent (excluding the number of carbon atoms in the substituent. The same applies hereinafter. ) represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, or an alkylthio group having 1 to 18 carbon atoms which may have a substituent. R ¹ and R ² are bonded to each other to form a ring, an alicyclic ring having 3 to 10 carbon atoms which may have a substituent, an aromatic ring having 6 to 10 carbon atoms which may have a substituent, optionally substituted oxygen atom-containing heterocyclic ring having 2 to 10 carbon atoms, optionally substituted carbon atom-containing heterocyclic ring having 2 to 10 carbon atoms, or carbon optionally having substituents It represents a heterocyclic ring containing 2 to 10 sulfur atoms and oxygen atoms. “R ¹ and R ² are bonded together to form a ring” means “R ¹ and R ² are bonded together to form a ring together with two carbon atoms in the thiophene skeleton of formula (1) and the number of carbon atoms in the ring formed by combining R ¹ and R ² includes two carbon atoms in the thiophene skeleton.

Examples of substituents include an aryl group having 6 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an alkylthio group having 1 to 18 carbon atoms, a carboxy group, a hydroxyl group, and a halogen atom. and a cyano group. The above alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with a carboxy group, hydroxyl group, halogen atom or cyano group. Also, two or more substituents may be condensed to form a ring.

Examples of the oxygen atom-containing heterocyclic ring include an oxirane ring, an oxetane ring, a furan ring, a hydrofuran ring, a pyran ring, a pyrone ring, a dioxane ring, a trioxane ring and the like.
Examples of the sulfur atom-containing heterocyclic ring include thiirane ring, thietane ring, thiophene ring, thiane ring, thiopyran ring, thiopyrylium ring, benzothiopyran ring, dithiane ring, dithiolane ring, and trithiane ring.

Examples of the sulfur atom- and oxygen atom-containing heterocyclic ring include an oxathiolane ring and an oxathian ring.
In formula (2), R ³ and R ⁴ each independently represent a hydrogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms, or R ³ and R ⁴ are It represents an optionally substituted C 3-6 oxygen atom-containing heterocyclic ring which is bonded to form a ring.

R ³ and R ⁴ are preferably an optionally substituted C 3-6 oxygen atom-containing heterocyclic ring formed by combining R ³ and R ⁴ to form a ring. “R ³ and R ⁴ are bonded to each other to form a ring” means “R ³ and R ⁴ are bonded to each other, adjacent two oxygen atoms, and two atoms in the thiophene skeleton of formula (2) The number of carbon atoms in the ring formed by combining R ³ and R ⁴ includes two carbon atoms in the thiophene skeleton.

The oxygen atom-containing heterocyclic ring includes a dioxane ring, a trioxane ring, and the like, preferably a dioxane ring. Examples of substituents include alkyl groups having 1 to 18 carbon atoms, aryl groups having 6 to 10 carbon atoms, heteroaryl groups having 5 to 10 carbon atoms, alkoxy groups having 1 to 18 carbon atoms, and alkylthio groups having 1 to 18 carbon atoms. groups, carboxy groups, hydroxyl groups, halogen atoms and cyano groups. The above alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with a carboxy group, hydroxyl group, halogen atom or cyano group. Also, two or more substituents may be condensed to form a ring.

[Conjugated conductive polymer]
The conjugated conductive polymer is not particularly limited as long as it is an organic polymer compound having a π-conjugated system in its main chain. Conjugated conductive polymers include polypyrroles, polythiophenes, polyisothianaphthenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and two types of polymer monomer units. Examples include copolymers containing the above.

Among these conjugated conductive polymers, polypyrrole, poly(N-methylpyrrole), polythiophene, poly(3-methylthiophene), poly(3-methoxythiophene) and poly(3,3, 4-ethylenedioxythiophene) is preferred. In particular, poly(3,4-ethylenedioxythiophene) (PEDOT) is more preferable because of its higher conductivity and excellent heat resistance.

[Polyanion]
The polyanion is a polymer having two or more monomer units having an anionic group, coordinates to the surface of the seed particles to form a protective colloid, and functions as a dopant for the conjugated conductive polymer. .

The anionic group includes, for example, a group composed of a sulfo group or a salt thereof (a group obtained by substituting a metal atom for a hydrogen atom of a sulfo group, such as SO ₃ Na, SO ₃ K, SO ₃ (NH ₄ )), A group consisting of a phosphate group or a salt thereof ₍ a group obtained by substituting a metal atom for a hydrogen atom of a phosphate group. For example, _PO4Na2 , _PO4NaH , _PO4K2 , _PO4KH , _{PO4 ( NH4} ) ₂ , PO ₄ (NH ₄ )H.), a monosubstituted phosphate group, a group consisting of a carboxyl group or a salt thereof (a group obtained by substituting a metal atom for a hydrogen atom of a carboxyl group; for example, COONa, COOK, COO (NH ₄ ).), monosubstituted sulfate ester groups. Among these, a strongly acidic group is preferred, a group consisting of a sulfo group or a salt thereof and a group consisting of a phosphoric acid group or a salt thereof are more preferred, and a group consisting of a sulfo group or a salt thereof is even more preferred.

The anionic groups may be attached directly to the polymer backbone or to side chains. When the anionic group is bound to the side chain, the doping effect becomes more pronounced, so it is preferably bound to the end of the side chain.

Polyanions may have substituents other than anionic groups. Examples of substituents include alkyl groups, hydroxyl groups, alkoxy groups, cyano groups, phenyl groups, hydroxyphenyl groups, ester groups, halogeno groups, alkenyl groups, imide groups, amide groups, amino groups, oxycarbonyl groups, and carbonyl groups. be done. Among these, an alkyl group, a hydroxyl group, a cyano group, a hydroxyphenyl group and an oxycarbonyl group are preferable, and an alkyl group, a hydroxyl group and a cyano group are more preferable. Substituents may be attached directly to the polymer backbone or to side chains. It is preferable that the substituent is attached to the end of the side chain in order to exhibit the effect of each substituent when the substituent is attached to the side chain.

The alkyl group that can be substituted in the polyanion can be expected to have the effect of increasing the solubility and dispersibility in aqueous media, the compatibility and dispersibility with the conjugated conductive polymer, and the like. Alkyl groups include chain alkyl groups such as methyl group, ethyl group, propyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, octyl group, decyl group and dodecyl group; A cycloalkyl group such as a cyclopentyl group and a cyclohexyl group can be mentioned. Considering solubility in aqueous media, dispersibility in conjugated conductive polymers, steric hindrance, etc., alkyl groups having 1 to 12 carbon atoms are more preferable.

The hydroxyl group that can be substituted in the polyanion facilitates the formation of hydrogen bonds with other hydrogen atoms, etc., and enhances solubility in aqueous media, compatibility with conjugated conductive polymers, dispersibility, and adhesion. expected to work. The hydroxyl group is preferably one bonded to the end of an alkyl group having 1 to 6 carbon atoms bonded to the main chain of the polymer.

The cyano group and hydroxyphenyl group that can be substituted in the polyanion are expected to have the effect of increasing the compatibility with the conjugated conductive polymer, the solubility in aqueous media, and the heat resistance. The cyano group is one directly bonded to the polymer main chain, one bonded to the end of an alkyl group having 1 to 7 carbon atoms bonded to the polymer main chain, or the end of an alkenyl group having 2 to 7 carbon atoms bonded to the polymer main chain. are preferred. A 4-hydroxyphenyl group is preferred as the hydroxyphenyl group.

The oxycarbonyl group that can be substituted in the polyanion is preferably an alkyloxycarbonyl group, an aryloxycarbonyl group, an alkyloxycarbonyl group or an aryloxycarbonyl group directly bonded to the main chain of the polymer, or an alkyloxycarbonyl group or an aryloxycarbonyl group with another functional group intervening.

The composition of the polymer backbone of the polyanion is not particularly limited. Polymer backbones include, for example, polyalkylenes, polyimides, polyamides, polyesters, and the like. Among these, polyalkylene is preferable from the viewpoint of synthesis and availability.

Polyalkylenes are polymers composed of repeating units of ethylenically unsaturated monomers. A polyalkylene may have carbon-carbon double bonds in its backbone. Examples of polyalkylene include polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly(3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polymethacrylate, polystyrene, polybutadiene, poly and isoprene.

Polyimides include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2,3,3-tetracarboxydiphenyl ether dianhydride, 2,2-[4,4 '-Di(dicarboxyphenyloxy)phenyl]propane dianhydride and other acid anhydrides and diamines such as oxydianiline, paraphenylenediamine, metaphenylenediamine and benzophenonediamine, and those obtained by polycondensation reaction. .

Polyamides include polyamide 6, polyamide 6,6, polyamide 6,10 and the like.
Examples of polyester include polyethylene terephthalate and polybutylene terephthalate.

Specific examples of polymers having at least one of a group consisting of a sulfo group and a salt of a sulfo group that are suitably used as polyanions include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyethyl acrylate sulfonic acid, and polyacrylic acid. acid butylsulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, and those in which all or part of the sulfo group is replaced with a group consisting of a salt of the sulfo group, and the like. be done. These may be homopolymers or copolymers containing two or more monomer units. Among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyethyl acrylate sulfonic acid, poly butyl acrylate sulfonic acid, and salts of sulfo groups of all or part of these are used from the viewpoint of imparting conductivity. Preferably, polystyrene sulfonic acid (PSS) and all or part of the sulfo group of polystyrene sulfonic acid are replaced with a group consisting of a salt of the sulfo group.

A polyanion, particularly a polymer having at least one of a group consisting of a sulfo group and a salt of a sulfo group, improves the dispersibility of the monomer compound in an aqueous medium and functions as a dopant for the conjugated conductive polymer.

The weight average molecular weight of the polyanion is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000, still more preferably 50,000 to 300,000. When the weight average molecular weight is within this range, the solubility of the polyanion in an aqueous medium and the doping of the polyanion into the conjugated conductive polymer are improved. In addition, the weight average molecular weight said here is the value measured as polystyrene conversion molecular weight using a gel permeation chromatography.

The polyanion may be selected from commercially available products having the above properties, or may be synthesized by a known method. A method for synthesizing a polyanion is described, for example, in JP-A-2005-76016.

The amount of polyanion used, that is, the total amount of polyanion used, including those used for forming protective colloids of seed particles, those charged in advance before the start of polymerization, and those added during polymerization, is determined by the anionic groups in the polyanion. is preferably 0.25 to 30 mol, more preferably 0.5 to 28 mol, still more preferably 0.8 to 25 mol, per 1 mol of the monomer compound.

In addition, the amount of the polyanion used relative to 100 parts by mass of the conjugated conductive polymer produced in this step is preferably 10 to 30,000 parts by mass, more preferably 30 to 20,000 parts by mass, and still more preferably 50 to 30,000 parts by mass. 15,000 parts by mass.
If the amount of the polyanion used is 10 parts by mass or more, the conductive polymer will have appropriate conductivity, and if it is 30,000 parts by mass or less, the conductive polymer will have good dispersibility in the aqueous medium.

[Seed particles]
Seed particles that may be used in the present invention are polymer particles that have been protectively colloidized with polyanions in an aqueous medium. The seed particles are preferably made of, for example, a polymer containing one or more ethylenically unsaturated monomers as structural units. The polymer may be of one type alone or a mixture of two or more types, and may be either crystalline or amorphous. In the case of crystallinity, the degree of crystallinity is preferably 50% or less.

Crystallinity can be measured with a differential scanning calorimeter or an X-ray diffractometer.
An ethylenically unsaturated monomer is a monomer having one or more polymerizable ethylenic carbon-carbon double bonds. Examples of ethylenically unsaturated monomers include (meth)acrylates having linear, branched or cyclic alkyl chains; aromatic vinyl compounds such as styrene and α-methylstyrene; heterocyclic compounds such as vinylpyrrolidone. Vinyl compounds; hydroxyalkyl (meth)acrylates; dialkylaminoalkyl (meth)acrylates such as dimethylaminoethyl acrylate; vinyl esters such as vinyl acetate and vinyl alkanoate; monoolefins such as ethylene, propylene, butylene and isobutylene; , conjugated diolefins optionally having a halogen atom such as chloroprene; α, β-unsaturated mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid; vinyl cyanide compounds; carbonyl group-containing vinyl compounds such as acrolein and diacetone acrylamide; These ethylenically unsaturated monomers may be used alone or in combination of two or more.

The ethylenically unsaturated monomer may also be a crosslinkable monomer, which is crosslinked by itself or in combination with the crosslinkable monomer and an ethylenically unsaturated compound having an active hydrogen group. good too. By using a crosslinked copolymer, the water resistance, moisture resistance, heat resistance, etc. of the conductive film can be improved. The crosslinkable monomer is an ethylenic carbon-carbon compound having two or more carbon double bonds, or an ethylenic carbon-carbon double bond having one or more and one other reactive group. It refers to a compound having the above.

Examples of crosslinkable monomers include epoxy group-containing α,β-ethylenically unsaturated compounds such as glycidyl (meth)acrylate; hydrolyzable alkoxysilyls such as vinyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane; Group-containing α,β-ethylenically unsaturated compounds; polyfunctional vinyl compounds such as ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, allyl (meth)acrylate, divinylbenzene, diallyl phthalate, etc. .

In addition, polyhydrazine compounds (in particular, oxalic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, (having two or more hydrazide groups such as polyacrylic acid hydrazide) may be combined for cross-linking.
The content of the crosslinkable monomer in the ethylenically unsaturated monomer is preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less.

(Production of Seed Particles Protectively Colloided by Polyanions)
The seed particles are protective colloidized with polyanions in an aqueous medium. A dispersion of protective colloidal seed particles dispersed in an aqueous medium can be prepared as a resin emulsion.

The polymerization reaction of the ethylenically unsaturated monomers in the production of the resin emulsion is a radical polymerization reaction, and a batch type, semi-continuous type, or continuous type method using an atmospheric pressure reactor or a pressure-resistant reactor. is done in In addition, from the viewpoint of reaction stability during polymerization and polymer homogeneity, an ethylenically unsaturated monomer is prepared by dissolving an ethylenically unsaturated monomer in an aqueous medium in a polyanion-containing liquid in which the polyanion is dissolved in advance in an aqueous medium. Preferably, the unsaturated monomer solution is added continuously or intermittently to polymerize the ethylenically unsaturated monomer.

The reaction temperature is usually 10 to 100°C, generally 30 to 90°C, though it depends on the decomposition temperature of the polymerization initiator. The reaction time is not particularly limited, and may be appropriately adjusted according to the amount of each component used, the type of polymerization initiator, the reaction temperature, and the like.

During radical polymerization, the polyanion, which is a protective colloid, contributes to the stability of the emulsion particles, but if necessary, emulsifiers such as anionic emulsifiers, nonionic emulsifiers and reactive emulsifiers, and aliphatic amines may be added to the polymerization system. may be added. The type and amount of emulsifier and aliphatic amine to be used may be appropriately adjusted according to various conditions including the amount of polyanion to be used and the composition of ethylenically unsaturated monomers.

Examples of emulsifiers used in such radical polymerization reactions include alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, alkyldiphenyl ether disulfonates, polyoxyalkylene alkyl sulfates, and polyoxyalkylene alkyl phosphates. Examples include anionic emulsifiers such as esters, and nonionic surfactants such as polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenol ethers, polyoxyalkylene fatty acid esters, and polyoxyalkylene sorbitan fatty acid esters.

Examples of aliphatic amines include primary amines such as octylamine, laurylamine, myristylamine, stearylamine and oleylamine; secondary amines such as dioctylamine, dilaurylamine, distearylamine and dioleylamine; and N,N-dimethyllauryl. amine, N,N-dimethylmyristylamine, N,N-dimethylpalmitylamine, N,N-dimethylstearylamine, N.I. tertiary amines such as N-dimethylbehenylamine, N,N-dimethyloleylamine, N-methyldidecylamine, N-methyldioleylamine;
You may use an emulsifier and an aliphatic amine individually by 1 type or in combination of 2 or more types.

In addition, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxyethyl cellulose, Water-soluble polymers such as hydroxypropyl cellulose and polyvinylpyrrolidone may be used together.

Water or a mixed solvent of water and a water-soluble solvent can be used as the aqueous medium used in producing the seed particle dispersion. The ratio of the water-soluble solvent in the mixed solvent is preferably 0 to 30% by mass. When the proportion of the water-soluble solvent is 30% by mass or less, the polymerization reaction of the resin emulsion can be stabilized. Examples of water-soluble solvents include alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as acetone, glycols such as ethylene glycol and propylene glycol, and ethers such as ethylene glycol monomethyl ether and ethylene glycol monobutyl ether. .

As a polymerization initiator used for radical polymerization, a known and commonly used one can be used. Examples of polymerization initiators include inorganic peroxides such as hydrogen peroxide, persulfate, ammonium persulfate, potassium persulfate and sodium persulfate, and organic peroxides such as benzoyl peroxide and t-butyl hydroperoxide. , 2,2′-azobisisobutyronitrile, and 4,4′-azobis(4-cyanovaleric acid). If necessary, these polymerization initiators may be combined with sodium sulfoxylate formaldehyde, ascorbic acids, sulfites, tartaric acid or its salts, iron (II) sulfate, or the like for redox polymerization. Chain transfer agents such as alcohols and mercaptans may also be used as necessary.

The amount of the ethylenically unsaturated monomer used in the production of protective colloidal seed particles is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, and still more preferably 100 parts by mass of the polyanion. is 30 to 70 parts by mass. If the amount of the ethylenically unsaturated monomer used is 10 parts by mass or more, the ratio of the conductive polymer containing seed particles protected by colloidal protection with polyanions to the conjugated conductive polymer is appropriate, and the polymerization Thickening due to can be suppressed. When the content is 100 parts by mass or less, the seed particles converted into protective colloids have good stability.

The d50 (50% median diameter based on volume) of the particle diameter of the seed particles dispersed in an aqueous medium that has been made into a protective colloid is preferably 0.01 to 10 μm, more preferably 0.05. ~1 μm, more preferably 0.1 to 0.8 μm. The particle size distribution of the seed particles can be measured with a Microtrac UPA type particle size distribution analyzer manufactured by Nikkiso Co., Ltd. When the d50 of the particle size of the seed particles dispersed in the aqueous medium is 0.01 μm or more, the dispersibility of the seed particles is good, and when it is 10 μm or less, the particles hardly settle.

<<Polymerization of Monomer Compound>>
Polymerization of the monomer compound is carried out in a liquid containing the monomer compound, polyanions and an aqueous medium. As a more specific embodiment of this liquid,
Examples include (i) a liquid containing the monomer compound, the polyanion and an aqueous medium, and (ii) a liquid containing the seed particles that have been protectively colloided with the monomer compound, the polyanion, and an aqueous medium.

[Monomer compound liquid]
In order to polymerize the monomer compound in the above solution, a dispersion containing a monomer compound and a polyanion, or a dispersion containing seed particles that have been made into a protective colloid by a monomer compound and a polyanion (hereinafter referred to as Together, it may simply be referred to as a "monomer compound liquid".) is prepared.

The monomer compound liquid may be one in which the monomer compound is dissolved, emulsified, or dispersed, and for this purpose, a powerful stirring device such as a homogenizer or an ultrasonic irradiation device is usually used. For example, in the case of emulsification by ultrasonic irradiation, the ultrasonic irradiation energy is not particularly limited as long as a uniform monomer compound liquid can be obtained. Ultrasonic irradiation is preferably performed at a power consumption of 5 to 500 W/L (liter) and an irradiation time of 0.1 to 2 hours/L (liter).

Further, when using a dispersion containing a monomer compound and seed particles converted into a protective colloid by a polyanion as the monomer compound liquid, from the viewpoint of suppressing aggregation of the conjugated conductive polymer generated by polymerization, It is preferable to include in the monomer compound liquid the same polyanions (ie, free polyanions) that are used for the protective colloidization of the seed particles. This polyanion (ie, free polyanion) can be incorporated by adding to the monomer compound liquid and dissolving, emulsifying or dispersing it. When the free polyanion is contained in the monomer compound liquid, the amount thereof is 5 to 99% by mass of the total amount of the polyanion used (that is, the total amount of the polyanion and the free polyanion used for protective colloidalization of the seed particles). is preferred, 10 to 90 mass % is more preferred, and 20 to 80 mass % is even more preferred.

[Aqueous medium]
The aqueous medium used for the polymerization of the monomer compound is a complex of a conjugated conductive polymer and seed particles that have been protective colloidalized by a polyanion, a complex of a conjugated conductive polymer and a polyanion, or two of these. The medium is not particularly limited as long as it can disperse the complex of seeds, but the same type of medium as the aqueous medium used for the seed particle dispersion is preferred.

Water or a mixed solvent of water and a water-soluble solvent can be used as the aqueous medium used for polymerization of the monomer compound.
Examples of water-soluble solvents include amides such as N-vinylpyrrolidone, hexamethylphosphortriamide, N-vinylformamide and N-vinylacetamide; phenols such as cresol, phenol and xylenol; methanol, ethanol, isopropyl alcohol and the like. monohydric alcohols; ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, diglycerin, isoprene glycol, butanediol, 1,5-pentanediol, 1,6- Polyhydric alcohols such as hexanediol, 1,9-nonanediol, neopentyl glycol; ketones such as acetone; carbonate compounds such as ethylene carbonate and propylene carbonate; dioxane, diethyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether , polypropylene glycol dialkyl ether, ethylene glycol monomethyl ether, ethers such as ethylene glycol monobutyl ether; heterocyclic compounds such as 3-methyl-2-oxazolidinone; acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile Nitriles can be mentioned. These solvents can be used singly or in combination of two or more.

The ratio of the water-soluble solvent in the mixed solvent is preferably 0 to 30% by mass. The aqueous medium more preferably contains 50 to 99% by mass of water, and more preferably uses water alone. When the proportion of the water-soluble solvent is 30% by mass or less, the polymerization reaction of the monomer compound can be stabilized.

The amount of the aqueous medium to be used is preferably 10 to 50,000 parts by mass with respect to 100 parts by mass in total of the monomer compound, the seed particles converted into protective colloid by the polyanion, and the polyanions not contributing to the protective colloid formation. , more preferably 50 to 10,000 parts by mass. When the amount of the aqueous medium used is 10 parts by mass or more, the viscosity during polymerization is appropriate, and when it is 50,000 parts by mass or less, the performance of the solid electrolytic capacitor is good.

[Oxidant]
In the polymerization of the above monomer compound, for example, when producing a dispersion containing polypyrroles or polythiophenes as a conjugated conductive polymer, the monomer compound liquid is heated to a predetermined temperature in the presence of an oxidizing agent. Polymerization is initiated by

Oxidizing agents include peroxodisulfates such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate and potassium peroxodisulfate; metal halide compounds such as boron trifluoride; ferric chloride, ferric sulfate, chloride transition metal compounds such as cupric; metal oxides such as silver oxide and cesium oxide; peroxides such as hydrogen peroxide and ozone; organic peroxides such as benzoyl peroxide; Of these, peroxodisulfate and peroxodisulfate are preferred, and peroxodisulfate is more preferred.
The oxidizing agents may be used singly or in combination of two or more.

[Polymerization temperature]
The temperature during polymerization of the monomer compound is usually 5 to 80°C, preferably 10 to 60°C, more preferably 15 to 40°C. When the temperature during polymerization is within this range, polymerization can be performed at an appropriate reaction rate, an increase in the viscosity of the reaction solution can be suppressed, and the dispersion containing the conjugated conductive polymer can be produced stably. It can be carried out in a very economical time, and the obtained conjugated conductive polymer tends to have a high conductivity. The temperature during polymerization can be controlled by using a known heater or cooler. Moreover, if necessary, the polymerization may be carried out while changing the temperature within the above range.

[Addition of protective colloidal seed particle dispersion]
During the polymerization of the monomer compound using the dispersion containing the monomer compound and seed particles converted to protective colloid, a dispersion of seed particles converted to protective colloid with a polyanion is further added to the reaction solution. is preferred. By further adding a predetermined amount of a dispersion of seed particles converted into a protective colloid during the polymerization of the monomer compound, thickening of the reaction liquid during polymerization can be suppressed, and the efficiency of stirring and mixing can be improved. load can be reduced. The amount of the protective colloidal seed particle dispersion to be added during polymerization is preferably 10 to 90% by mass, more preferably 20 to 80% by mass of the total amount of the protective colloidal seed particle dispersion used. , 30 to 70 mass % is more preferable.

[Addition of polyanion]
A polyanion may be further added to the reaction solution during the polymerization of the monomer compound. By further adding a predetermined amount of part of the polyanion during the polymerization of the monomer compound, thickening of the reaction solution during polymerization can be suppressed, and the efficiency of stirring and mixing can be improved, and the load on the production apparatus can be reduced. . The amount of polyanion added during polymerization is preferably 0 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass of the total amount of polyanion used.

(Preparation of dispersion liquid (2) containing conjugated conductive polymer)
In step (A), a dispersion liquid (1) containing a conjugated conductive polymer is prepared as described above, and the dispersion liquid (1) is subjected to a dispersion treatment to disperse the conjugated conductive polymer. Dispersion liquid (2) containing (hereinafter also referred to as "conjugated conductive polymer-containing dispersion liquid (2)") is obtained.

Two or more dispersions (1) of different types of conjugated conductive polymers may be prepared, and the dispersion obtained by mixing these may be subjected to dispersion treatment.
The dispersion (1) containing the conjugated conductive polymer comprises (i) a composite of the conjugated conductive polymer and the polyanion, and (ii) a protective colloid formed by the conjugated conductive polymer and the polyanion. and at least one selected from a complex with seed particles is a dispersion dispersed in an aqueous medium.

The composite may aggregate as the polymerization of the polymerizable compound progresses.
In order to improve the capacitance and ESR, it is necessary to improve the impregnation of the porous anode body. Fine particles of 10 μm are dispersed.

[Distributed processing]
The dispersion treatment is to crush the composite to the size of the fine particles, and is preferably carried out by a powerful stirring device such as a homogenizer or ultrasonic irradiation. Dispersion treatment may be performed when the polymerizable compound is polymerized. That is, the dispersion liquid (1) subjected to the dispersion treatment may contain the unreacted polymerizable compound. For example, JP-A-2007-332183 describes a method of polymerizing a conjugated conductive polymer while stirring at a shear rate of 5,000 s ⁻¹ or higher.

In the case of ultrasonic irradiation, it is preferable to carry out at a power consumption of 5 to 500 W/L per dispersion treatment liquid. Distributed processing may be either a flow method or a batch method.
When using a high pressure homogenizer, the pressure of the high pressure homogenizer is preferably 10-2000 bar, more preferably 20-1500 bar, more preferably 50-1000 bar. If the pressure of the high-pressure homogenizer is 10 bar or more, the dispersion treatment is efficiently performed, and the performance of the solid electrolytic capacitor is good. If the pressure of the high-pressure homogenizer is 2000 bar or less, workability during dispersion treatment is good.

For example, when dispersing 1500 ml of a dispersion liquid using a high-pressure homogenizer having a dispersion processing capacity of 500 ml/min, it takes 3 minutes to disperse the entire amount of the dispersion liquid once. The total dispersion treatment time is preferably 15 to 900 minutes, more preferably 30 to 600 minutes, still more preferably 60 to 300 minutes. If the dispersion treatment time of the high-pressure homogenizer is 3 minutes or more, the effect of the dispersion treatment is exhibited, and the performance of the solid electrolytic capacitor is good. Efficiency of the dispersion treatment is good if the number of times of dispersion treatment with the high-pressure homogenizer is 900 minutes or less.

[Concentration of dispersion]
The concentration of the conjugated conductive polymer in the dispersion liquid (1) when performing the dispersion treatment is not particularly limited as long as it does not impair the productivity in the dispersion treatment, but from the viewpoint of impregnation into the solid electrolytic capacitor. The finished concentration, that is, the concentration of the conjugated conductive polymer in the dispersion (2) obtained in step (A) is preferably 1.0 to 10.0% by mass. If it is 1.0% by mass or more, the equivalent series resistance of the solid electrolytic capacitor is good. If it is 10.0% by mass or less, the electrostatic capacity is good.

The concentration of the conjugated conductive polymer in dispersion (1) may be reduced by diluting with an aqueous medium. The timing of dilution may be before the dispersing process, during the dispersing process, or after the dispersing process, but it is preferably performed during the dispersing process. By diluting with an aqueous medium during the dispersing treatment, the dispersing treatment can be efficiently performed at a high concentration, and the influence of reaggregation due to dilution can be reduced.

[Addition of salt compound]
In the present invention, in step (A), a salt compound is added to the dispersion (1) or to the aqueous medium on the way to obtain the dispersion (1). By adding a salt compound, it becomes possible to increase the ionic strength of the dispersion liquid, aggregate the dispersed composite, and increase the viscosity of the dispersion liquid (1). By dispersing the composite again after increasing the viscosity, the deaggregation of the composite can be promoted.

Although the details of the reason why the electrostatic capacity and ESR of the solid electrolytic capacitor are improved by promoting the deaggregation of the composite are unknown, it is presumed that the abundance of the conjugated conductive polymer on the surface of the composite changes. be.

The timing of adding the salt compound is not particularly limited, but in order to ensure uniformity, it is preferably during stirring in the polymerization of the monomer compound or during dispersion processing of the dispersion liquid (1). In the case of desalting, which will be described later, a salt compound may be added and dispersed again after desalting. It is preferable to add the salt compound during the dispersing treatment of the dispersion liquid (1), and it is more preferable to add the salt compound 10 minutes before the end of the dispersing treatment.

The salt compound is not particularly limited as long as it dissolves in an aqueous medium, increases the ionic strength of the dispersion, and increases the viscosity of the dispersion.
For example, it is preferably at least one salt compound selected from inorganic salts and organic salts that dissolves in an aqueous medium, increases the ionic strength of the dispersion, and thickens the dispersion.

Organic salts include citrate, lactate, glycolate, gluconate, acetate, propionate, fumarate, oxalate and tartrate, more specifically calcium acetate. , magnesium acetate, and the like.

Inorganic salts include hydrochlorides, carbonates, hydrogen carbonates, sulfates, hydrogen phosphates, and phosphates, and more specifically aluminum chloride, ammonium chloride, sodium nitrate, magnesium sulfate, sulfuric acid. Examples include, but are not limited to, aluminum, ammonium sulfate, potassium sulfate, sodium sulfate, and the like. Among them, ammonium chloride, potassium sulfate and ammonium sulfate are preferred. These salt compounds may be used individually by 1 type, and may use 2 or more types together.

The amount added is preferably 0.01 to 30% by mass, more preferably 0.01 to 15% by mass, more preferably 0.01 to 5% by mass, based on the total amount (100% by mass) of the dispersion liquid (2). More preferably, the amount is mass %. If the amount added is 0.01% by mass or more, the dispersion liquid (1) is sufficiently thickened, and if it is 30% by mass or less, the efficiency of the dispersion treatment is good.

The viscosity of the dispersion immediately after thickening (for example, the viscosity 6 minutes after adding the salt compound) is preferably 1.05 to 100 of the viscosity before thickening (for example, the viscosity immediately before adding the salt compound). 0 times the viscosity, more preferably 1.10 to 50.0 times the viscosity, and the upper limit may be, for example, 15 times. When the viscosity of the dispersion immediately after thickening is 1.05 times or more the viscosity before thickening, the conjugated conductive polymer is efficiently deaggregated, and the performance of the solid electrolytic capacitor is good. . If the viscosity of the dispersion liquid immediately after thickening is 100.0 times or less of the viscosity before thickening, the efficiency of the dispersion treatment is good.

[Additive]
Various additives may be added to the dispersion (1) containing the conjugated conductive polymer, if necessary. The additive is not particularly limited as long as it can be mixed with the conjugated conductive polymer and the seed particles or the polyanion that has been made into a protective colloid by the polyanion.

Examples of such additives include neutralizing agents, water-soluble polymer compounds, water-dispersible compounds, alkaline compounds, surfactants, antifoaming agents, coupling agents, antioxidants, and electrical conductivity improvers. mentioned. These additives can be used singly or in combination of two or more.

A water-soluble polymer compound is a water-soluble polymer having a cationic group or a nonionic group in the main chain or side chain of the polymer. Specific examples of water-soluble polymer compounds include polyoxyalkylene, water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, water-soluble polyimide, water-soluble polyacryl, water-soluble polyacrylamide, polyvinyl alcohol, and polyacrylic acid. . Among these, polyoxyalkylene is preferred.

Specific examples of polyoxyalkylene include diethylene glycol, triethylene glycol, oligopolyethylene glycol, triethylene glycol monochlorhydrin, diethylene glycol monochlorhydrin, oligoethylene glycol monochlorhydrin, triethylene glycol monobromohydrin, diethylene glycol monobromohydrin, Oligoethylene glycol monobromhydrin, polyethylene glycol, glycidyl ethers, polyethylene glycol glycidyl ethers, polyethylene oxide, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether diethylene glycol dibutyl ether, diethylene glycol Propylene glycol, tripropylene glycol, polypropylene glycol, polypropylene dioxide, polyoxyethylene alkyl ether, polyoxyethylene glycerin fatty acid ester, and polyoxyethylene fatty acid amide.

A water-dispersible compound is a compound having a low hydrophilicity partially substituted with a highly hydrophilic functional group, or a compound having a highly hydrophilic functional group adsorbed around a low hydrophilic compound. (for example, an emulsion) that disperses in water without precipitating. Specific examples include polyesters, polyurethanes, acrylic resins, silicone resins, and emulsions of these polymers. Block copolymers and graft copolymers of acrylic resins and other copolymers such as polyesters and polyurethanes are also included.

The water-soluble polymer compound and the water-dispersible compound can be used singly or in combination of two or more. By adding a water-soluble polymer compound and a water-dispersible compound, the viscosity of the dispersion containing the conductive polymer can be adjusted, and coating performance can be improved.

The amount of the water-soluble polymer compound and the water-dispersible compound to be used is preferably 10 to 100,000 parts by mass with respect to a total of 100 parts by mass of the conjugated conductive polymer and the seed particles converted into a protective colloid by the polyanion. , more preferably 25 to 50,000 parts by mass, more preferably 50 to 20,000 parts by mass. When the amount of the water-soluble polymer compound and the water-dispersible compound is in the range of 10 to 100,000 parts by mass, appropriate conductivity can be expressed, and a good equivalent series resistance (ESR) of the solid electrolytic capacitor can be obtained. be done.

As the alkaline compound, known inorganic alkaline compounds and organic alkaline compounds can be used. Examples of inorganic alkaline compounds include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Examples of organic alkaline compounds include aromatic amines, aliphatic amines, alkali metal alkoxides, and the like. The addition of an alkaline compound can impart corrosion resistance to articles to which the dispersion is applied, and can adjust the pH of the conjugated conductive polymer-containing dispersion.

Among aromatic amines, nitrogen-containing heteroaryl ring compounds are preferred. A nitrogen-containing heteroaryl ring compound is a nitrogen-containing heterocyclic ring compound that exhibits aromaticity. In aromatic amines, the nitrogen atom contained in the hetero ring has a conjugated relationship with another atom.

Nitrogen-containing heteroaryl ring compounds include, for example, pyridines, imidazoles, pyrimidines, pyrazines, and triazines. Among these, pyridines, imidazoles, and pyrimidines are preferable from the viewpoint of solvent solubility.

Examples of aliphatic amines include ethylmorpholine, ethylamine, n-octylamine, diethylamine, diisobutylamine, methylethylamine, trimethylamine, triethylamine, allylamine, 2-ethylaminoethanol, 2,2'-iminodiethanol, and N-ethylethylenediamine. is mentioned.

Examples of alkali metal alkoxides include sodium alkoxides such as sodium methoxide and sodium ethoxide, potassium alkoxides, and calcium alkoxides.

Examples of surfactants include anionic surfactants such as carboxylates, sulfonates, sulfates and phosphates; cationic surfactants such as amine salts and quaternary ammonium salts; amphoteric surfactants such as carboxylates and imidazolium betaine; and nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene glycerin fatty acid esters, ethylene glycol fatty acid esters and polyoxyethylene fatty acid amides.

Antifoaming agents include, for example, silicone resins, polydimethylsiloxane, and silicone resins.
Examples of antioxidants include phenol antioxidants, amine antioxidants, phosphorus antioxidants, sulfur antioxidants, sugars, and vitamins.

The electrical conductivity improver is not particularly limited as long as it increases the electrical conductivity of the dispersion containing the conductive polymer. Examples of electrical conductivity improvers include compounds containing an ether bond such as tetrahydrofuran; compounds containing a lactone group such as γ-butyrolactone and γ-valerolactone; caprolactam, N-methylcaprolactam, N,N-dimethylacetamide, N - compounds containing an amide or lactam group such as methylacetamide, N,N-dimethylformamide, N-methylformamide, N-methylformanilide, N-methylpyrrolidone, N-octylpyrrolidone, pyrrolidone; tetramethylene sulfone, dimethylsulfoxide, etc. sulfone compounds or sulfoxide compounds; sugars or sugar derivatives such as sucrose, glucose, fructose and lactose; sugar alcohols such as sorbitol and mannitol; imides such as succinimide and maleimide; and di- or poly-alcohols such as ethylene glycol, propylene glycol, glycerin, diethylene glycol and triethylene glycol. Among these, tetrahydrofuran, N-methylformamide, N-methylpyrrolidone, ethylene glycol, propylene glycol, glycerin, dimethyl sulfoxide, and sorbitol are preferred from the viewpoint of improving electrical conductivity, and among these, ethylene glycol, diethylene glycol, triethylene glycol, and propylene are preferred. Glycol and glycerin are more preferred. The electrical conductivity improvers may be used singly or in combination of two or more.

[Desalination]
After finishing the dispersion treatment, the dispersion (1) may be desalted. The composite of the conjugated conductive polymer and the polyanion dispersed to the primary particles in the step (A) can maintain its dispersibility even if it is allowed to stand by desalting.
The desalting method is not particularly limited, and desalting can be performed by a dialysis method, a centrifugal washing method, an ion exchange method, or the like.

<Step (B) of Adhering Conjugated-Based Conductive Polymer-Containing Dispersion (2) to Porous Anode>
In the method for producing a solid electrolytic capacitor of the present invention, the conjugated conductive polymer-containing dispersion (2) obtained in the above step (A) is mixed with an anode body made of a valve metal and at least one surface of the anode body. a step (B) of adhering to the surface of the porous anode body having a dielectric film formed on the portion thereof;

The solid electrolytic capacitor according to the manufacturing method of the present invention may use, for example, a porous electrode formed by sintering a valve metal powder having a high surface area, or a porous membrane obtained by etching a valve metal foil. can.

The valve metals include aluminum (Al), beryllium (Be), bismuth (Bi), magnesium (Mg), germanium (Ge), hafnium (Hf), niobium (Nb), antimony (Sb), and silicon (Si). , tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), tungsten (W) and zirconium (Zr), and alloys or compounds of at least one of these metals with other elements. . Among them, an electrode material composed of a valve metal such as Al, Nb, or Ta is preferable.

A porous electrode made of a valve metal is made into a porous anode body by forming a dielectric oxide film on the surface thereof by, for example, anodization.
The porous electrode can be anodized, for example, by applying a voltage in a phosphoric acid solution to form a dielectric oxide film on the surface of the porous electrode. The magnitude of the formation voltage can be determined by the thickness of the dielectric oxide film and the withstand voltage of the capacitor. A formation voltage is preferably 1 to 800V, more preferably 1 to 300V.

Next, the conjugated conductive polymer-containing dispersion (2) is adhered to the porous anode body. Examples of the method of adhesion include known methods such as coating, spraying, and immersion. Among them, the immersion method is preferable because the conjugated conductive polymer-containing dispersion (2) can be evenly and uniformly adhered to and permeated into the porous anode body. In addition, the impregnation may be performed under reduced pressure in order to impregnate the finer details of the porous anode body.
The immersion time is usually 10 seconds to 5 minutes, and the temperature of the conjugated conductive polymer-containing dispersion (2) is usually 10 to 35° C., depending on the type of aqueous medium.

<Step (C) of Forming Solid Electrolyte Layer>
In the method for producing a solid electrolytic capacitor of the present invention, the aqueous medium is removed from the conjugated conductive polymer-containing dispersion (2) adhering to the porous anode body obtained in the above step (B) to form a solid electrolyte layer. has a step (C) of forming The removal of the aqueous medium in this step (C) does not mean that all of the aqueous medium is removed, and part of the aqueous medium may remain to the extent that it does not affect the production of the solid electrolytic capacitor.

As a method for removing the aqueous medium, drying by heat treatment is preferable from the viewpoint of efficiency. Heating conditions can be determined in consideration of the boiling point and volatility of the aqueous medium. Heating is preferably carried out in a temperature range in which the conductive polymer is not deteriorated by oxygen, for example, 10 to 300°C, preferably 50 to 200°C. The heat treatment time is preferably 5 seconds to several hours. The heat treatment may be carried out in the atmosphere using, for example, a hot plate, oven, hot air dryer, or under reduced pressure to expedite the heat treatment.

In the present invention, the step (B) of attaching the conjugated conductive polymer-containing dispersion (2) and the step (C) of forming the solid electrolyte layer are performed once or twice depending on the type of electrode body. The above steps may be repeated. However, in the step (B) for the second and subsequent times, the dispersion liquid (2) is allowed to adhere to the surface of the solid electrolyte layer formed in the step (C). A part or all of the aqueous medium may be removed by heat treatment each time the dispersion is deposited, or the dispersion may be successively deposited several times and finally the aqueous medium is removed. Furthermore, any electrolytic solution may be impregnated after part or all of the aqueous medium contained in the deposited dispersion is removed.

Through the above steps (A) to (C), a solid body having a porous anode made of a valve action metal having a dielectric coating on its surface and a solid electrolyte layer provided on the surface of the dielectric coating Electrolytic capacitors are manufactured.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Methods for measuring physical properties of dispersions in Examples and Comparative Examples are as follows.

(1) Solid content concentration For the solid content concentration of each example, approximately 10 g of the sample obtained in each example was measured using an infrared moisture meter (Model FD-720 manufactured by Ketto Science Laboratory Co., Ltd., heating conditions 110 ° C./30 minutes. ), and the evaporation residue was calculated as a solid content.

(2) pH
The pH of the dispersion liquid obtained in each example was measured at 25° C. using a pH meter (model HM-30G manufactured by Toa DKK Co., Ltd.).

(3) Viscosity The viscosity of the dispersion liquid obtained in each example was measured at 23° C. and 60 rpm using a rotational viscometer (model TV25 viscometer manufactured by Toki Sangyo Co., Ltd.).

(4) Particle Size of Seed Particles The particle size of the seed particles (including the thickness of the polyanion layer) was measured using a Microtrac UPA particle size distribution analyzer manufactured by Nikkiso Co., Ltd.

(5) Weight Average Molecular Weight of Sodium Polystyrene Sulfonate The weight average molecular weight was measured using gel permeation chromatography. "Shodex (registered trademark) GPC 101" (column OHPak SB-806M HQ) manufactured by Showa Denko Co., Ltd. was used for the measurement, and the measurement conditions were a column temperature of 40°C, an eluent of water, and an elution rate of 1 ml/min. . The weight-average molecular weight is indicated by the standard polystyrene equivalent molecular weight (Mw).

(6) Capacitance and equivalent series resistance of solid electrolytic capacitor element Measured using Model E4980A).

[Example 1]
(Preparation of dispersion of seed particles protected with polyanion colloid)
86 g of styrene, 49 g of 2-ethylhexyl acrylate, 15 g of divinylbenzene, and 500 g of a 22% by mass aqueous solution of sodium polystyrene sulfonate (Polynas PS-5, weight average molecular weight: about 120,000, manufactured by Tosoh Organic Chemical Co., Ltd.) were mixed with stirring, and ethylene was added. A polyunsaturated monomer mixture was prepared. On the other hand, while stirring 1000 g of a 22% by mass aqueous solution of sodium polystyrene sulfonate (same as above), the temperature was raised to 80° C., and 2 g of potassium persulfate was added thereto. To the solution thus obtained, the ethylenically unsaturated monomer mixture and 40 g of a 2.5% by mass aqueous solution of potassium persulfate were added dropwise over 2 hours and 2.5 hours, respectively. After completion of dropping, the reaction solution was kept at 80°C for 2 hours and then cooled to room temperature (25°C). 1500 ml of a cation exchange resin (IR120B-H, manufactured by Organo Co., Ltd.) and 1500 ml of an anion exchange resin (IRA410-OH, manufactured by Organo Co., Ltd.) were added to the resulting reaction solution, and after stirring for 12 hours, the ion exchange resin was added. was filtered out. Ion-exchanged water (hereinafter simply referred to as water) was added to the filtrate to adjust the solid content concentration to 15.0% by mass, and seed particles (particle size d50:0 .46 μm) dispersion was obtained.

(Step (A): Production of conjugated conductive polymer dispersion (2) by polymerization)
(Polymerization step (A-1))
In a 1 L polyethylene container, 223.2 g of water, 31.5 g of a 12% by weight aqueous solution of sodium polystyrene sulfonate (same as above), and 34.0 g of the polyanion-protected colloidal dispersion of seed particles prepared as described above were added to 32 The mixture was stirred and mixed at ℃. To this mixture, 2.80 g of 3,4-ethylenedioxythiophene was added at 32° C. and emulsified and mixed for 30 minutes with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd., Robomix; 4000 rpm) to obtain a monomer. A compound dispersion was prepared. The amount of the group consisting of the sulfo group and the salt of the sulfo group was 1.9 mol per 1 mol of 3,4-ethylenedioxythiophene. The sulfo group and the like are derived from sodium polystyrene sulfonate in the 12% by mass aqueous solution of sodium polystyrene sulfonate and the dispersion.

The monomer compound dispersion was put into a 1 L stainless steel container connected to a high shear mixer (Milder (registered trademark) 303V; 5000 rpm, manufactured by Taiheiyo Kiko Co., Ltd.) and a circulation pump, and stirred with a stirring blade and a high shear mixer. Then, 5.89 g of sodium peroxodisulfate as an oxidizing agent and 6.88 g of a 1% by mass aqueous solution of iron (III) sulfate hexahydrate were added to the dispersion to initiate the polymerization reaction. got it started. Five minutes after the start of the polymerization reaction, 1.5 g of ammonium sulfate was added as a salt compound, and the polymerization reaction was carried out for 24 hours to obtain a dispersion liquid (1-1) containing a conjugated conductive polymer. The amount of the polyanion used was 261 parts by mass with respect to 100 parts of the conjugated conductive polymer.

(High pressure dispersion treatment step (A-2))
Pure water was added to 304.27 g of the dispersion liquid (1-1) having a solid content concentration of 5.80% to adjust the solid content concentration to 3.00% by mass and the total volume to 1500 mL. After that, the dispersion (1-1) (hereinafter referred to as the dispersion (1-1) and various operations (addition of pure water, high-pressure dispersion treatment, ion exchange, etc.) are performed without distinction. Described as "dispersion (1-1)" (excluding the dispersion (2-1), which is the final product)), was subjected to dispersion pressure with a high-pressure homogenizer (TWIN PANDA 600, manufactured by Niro Soavi). was set to 400 bar and high-pressure dispersion treatment was continuously performed for 45 minutes. After that, pure water was added to adjust the dispersion liquid (1-1) to a solid content concentration of 2.50% by mass and a total amount of 1500 mL, and the dispersion liquid (1-1) was again subjected to high pressure dispersion at 400 bar for 135 minutes continuously with a high pressure homogenizer. processed.

(Desalting step (A-3))
Immediately after the dispersion treatment, ion exchange was performed with 100.5 g of a cation exchange resin and 87.9 g of an anion exchange resin for 3 hours to desalt. Thereafter, the dispersion liquid (1-1) was filtered through a filter with a pore size of 5 μm, and then filtered through a filter with a pore size of 3 μm. A dispersion liquid (2-1) of the conjugated conductive polymer of No. 9 was obtained.
An outline of step (A) is shown in FIG.

(Formation of porous anode body having dielectric oxide film on its surface)
A porous anode body having a dielectric oxide film on its surface and used for a solid electrolytic capacitor was produced by the method described in JP-A-2011-77257. That is, using a niobium powder for a capacitor, a porous anode body with an anode lead was produced in which a dielectric oxide film containing niobium pentoxide was formed on the surface of the anode body. The capacitance of this porous anode body in 20 mass % sulfuric acid was 21.4 μF.

(Steps (B) and (C): Production of Solid Electrolytic Capacitor)
The porous anode body obtained by the above method was impregnated with the conjugated conductive polymer dispersion (2-1) for 1 minute in an atmosphere of 25° C., and then dried in a hot air dryer (manufactured by TABAI, model ST-110) at 120° C. for 30 minutes. This treatment was repeated 10 times to form a solid electrolyte layer on the surface of the dielectric oxide film of the porous anode, thereby obtaining a solid electrolytic capacitor.

Next, a carbon paste was applied to the solid electrolytic capacitor so as not to contact the anode lead terminal, and dried. Further, a silver paste was applied to make contact between the anode and the cathode, and dried on a lead frame. The anode lead wire was electrically connected to the anode lead portion of the lead frame and sealed with resin to obtain a solid electrolytic capacitor element.

[Example 2]
A solid electrolytic capacitor element was produced in the same manner as in Example 1, except that the timing of addition of the salt compound was changed to 24 hours after the start of polymerization (that is, immediately before the start of high-pressure dispersion treatment).

[Example 3]
A solid electrolytic capacitor element was produced in the same manner as in Example 1, except that the timing of addition of the salt compound was changed to 90 minutes after the start of the high-pressure dispersion treatment.

[Example 4]
(Second high pressure dispersion treatment step (A-4))
A dispersion containing a conjugated conductive polymer (hereinafter " Dispersion liquid (1-4)” was obtained. 1.5 g of ammonium sulfate was added as a salt compound to 1500 mL of the dispersion (1-4), and a high-pressure homogenizer (TWIN PANDA 600, manufactured by Niro Soavi) was used to continuously perform high-pressure dispersion treatment for 135 minutes at a dispersion pressure of 400 bar (hereinafter referred to as "2 (also referred to as “second high-pressure dispersion treatment”).

(Desalting step (A-5))
Immediately after the dispersion treatment, ion exchange was performed with 100.5 g of a cation exchange resin and 87.9 g of an anion exchange resin for 3 hours to desalt. After the desalted dispersion (1-4) was filtered through a filter with a pore size of 5 μm, it was further filtered through a filter with a pore size of 3 μm, and pure water was added to adjust the solid content concentration to 2.0%. A dispersion (2-4) of a conjugated conductive polymer having a pH of 1.9 was obtained.
A solid electrolytic capacitor element was produced in the same manner as in Example 1, except that the dispersion (2-1) was changed to the dispersion (2-4).

[Example 5]
A solid electrolytic capacitor element was produced in the same manner as in Example 4, except that the timing of addition of the salt compound was changed to 90 minutes after the start of the second high-pressure dispersion treatment.

[Comparative Example 1]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1, except that the salt compound was not added.

[Comparative Example 2]
A solid electrolytic capacitor element was produced in the same manner as in Example 4 or 5, except that the salt compound was not added.
Table 1 shows the manufacturing conditions and evaluation results (capacitance and equivalent series resistance) of Examples 1 to 5 and Comparative Examples 1 and 2.

From the results in Table 1, the solid electrolytic capacitors of Examples 1 to 5 in which the conjugated conductive polymer dispersion (2) was used in the step of adhering to the porous anode body made of a valve metal having a dielectric coating. The element has a higher capacity expression rate (capacitance) and an equivalent series resistance (ESR ) is low.

In the present invention, the dispersion liquid (1) containing the polyanion and the conjugated conductive polymer is dispersed, so the solid electrolyte layer formed by removing the aqueous medium from the dispersion liquid (2), and all possible structures of solid electrolytic capacitors are impractical.

Claims (16)

Polymerizing a monomer compound for obtaining a conjugated conductive polymer in a liquid containing a polyanion and an aqueous medium to obtain a dispersion (1) containing the conjugated conductive polymer, and (1) is subjected to dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer (A),
In the step (A), conjugation by adding a salt compound to the dispersion (1) during the dispersion treatment or to the aqueous medium on the way to obtain the dispersion (1) during the polymerization of the monomer compound A method for producing a dispersion (2) containing a system conductive polymer. Polymerizing a monomer compound for obtaining a conjugated conductive polymer in a liquid containing a polyanion and an aqueous medium to obtain a dispersion (1) containing the conjugated conductive polymer, and (1) is subjected to dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer (A),
The dispersion treatment is performed after the polymerization,
In the step (A), a salt compound is added to the dispersion (1) after the polymerization of the monomer compound and before the dispersion treatment.
A method for producing a dispersion (2) containing a conjugated conductive polymer. The dispersion liquid (2) containing the conjugated conductive polymer according to claim 1 or 2 , wherein the amount of the salt compound added is 0.01 to 30% by mass of the amount of the dispersion liquid (2). ) manufacturing method. The dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 3, wherein the salt compound is at least one selected from organic acid salts and inorganic acid salts. Production method. The salt compound is citrate, lactate, glycolate, gluconate, acetate, propionate, fumarate, oxalate, tartrate, hydrochloride, carbonate, bicarbonate, sulfate A dispersion containing the conjugated conductive polymer according to any one of claims 1 to 4 , which is at least one selected from the group consisting of salts, hydrogen phosphates, and phosphates (2 ) manufacturing method. A method for producing a dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 5 , wherein desalting is performed after the dispersion treatment. A method for producing a dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 6 , wherein the dispersion treatment is performed using a high-pressure homogenizer. A method for producing a dispersion (2) containing a conjugated conductive polymer according to any one of claims 1 to 7 , wherein seed particles that have been protectively colloidized with a polyanion are dispersed in the aqueous medium. 9. The method for producing a dispersion (2) containing a conjugated conductive polymer according to claim 8 , wherein the seed particles are particles of an ethylenically unsaturated monomer polymer. 10. The method for producing a dispersion (2) containing a conjugated conductive polymer according to claim 8 or 9 , wherein the d50 particle size of the seed particles converted into protective colloid with the polyanion is 0.01 to 10 μm. The dispersion containing the conjugated conductive polymer according to any one of claims 1 to 10 , wherein the monomer compound is at least one selected from the group consisting of pyrrole compounds, aniline compounds, and thiophene compounds. Method for producing liquid (2). The monomer compound is represented by the following formula (1)

(wherein R ¹ and R ² are each independently a hydrogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 18 carbon atoms, an optionally substituted C 1 to 18 or an optionally substituted alkylthio group having ¹ to 18 carbon atoms, or R ¹ and R ² are bonded to ^each other and have a substituent alicyclic ring having 3 to 10 carbon atoms which may be substituted, aromatic ring having 6 to 10 carbon atoms and optionally having substituents, oxygen atom-containing heterocyclic ring having 2 to 10 carbon atoms and optionally having substituents, substituents represents a sulfur atom-containing heterocyclic ring having 2 to 10 carbon atoms which may have a A method for producing a dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 11 . The dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 12 , wherein the polyanion is a polymer having at least one of a group consisting of a sulfo group and a salt of a sulfo group. Production method. 14. The polyanion according to any one of claims 1 to 13 , wherein the proportion of anionic groups in the polyanion is 0.25 to 30.00 mol per 1 mol of the monomer compound. A method for producing a dispersion (2) containing a conjugated conductive polymer of A method for manufacturing a solid electrolytic capacitor having a porous anode body made of a valve metal having a dielectric coating on its surface and a solid electrolyte layer provided on the surface of the dielectric coating, comprising:
A step (A) of obtaining a dispersion (2) by a method for producing a dispersion (2) containing the conjugated conductive polymer according to any one of claims 1 to 14 ;
a step (B) of attaching the dispersion (2) to a porous anode body made of a valve action metal having a dielectric coating on the surface; Step (C) of removing the medium and forming a solid electrolyte layer
have
A method for manufacturing a solid electrolytic capacitor. A solid electrolytic capacitor obtained by the manufacturing method according to claim 15 .

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