JP2006287182A - Capacitor and its method for manufacturing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor in which the corrosion of a dielectric layer is prevented, and to provide its method for manufacturing. <P>SOLUTION: The capacitor 10 comprises a positive electrode 11, composed of porous material of valve metal, a dielectric layer 12 formed by oxidization of the surface of the positive electrode 11, and a negative electrode 13 formed on the dielectric layer 12 and provided with a solid electrolite layer 13a, wherein the solid electric layer 13a of the negative electrode 13 contains π conjugation based conductive polymer, polyanion, and solvent, and is formed by applying conductive polymer solution of pH 3 to 13 at 25°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor such as an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, a niobium electrolytic capacitor, and a method for manufacturing the same.

 In recent years, with the digitization of electronic devices, capacitors used in electronic devices are required to reduce impedance in a high frequency region. Conventionally, in order to meet this requirement, so-called functional capacitors, in which an oxide film of valve metal such as aluminum, tantalum, or niobium is used as a dielectric, and a π-conjugated conductive polymer is formed on this surface as a cathode. Is used.

 As shown in Patent Document 1, the structure of this functional capacitor includes an anode made of a valve metal porous body, a dielectric layer formed by oxidizing the surface of the anode, a solid electrolyte layer, carbon In general, a layer and a cathode having a silver layer laminated thereon are used, and a π-conjugated conductive polymer is used as a solid electrolyte layer of a capacitor.

As a method for forming a film of a π-conjugated conductive polymer, an electrolytic polymerization method and a chemical oxidative polymerization method are widely known.
In the electrolytic polymerization method described in Patent Document 2 and the like, a conductive layer made of manganese oxide is formed in advance on the surface of the valve metal porous body, and then this is used as an electrode for electrolytic polymerization. Therefore, there is a problem that the conductive layer is complicated and the manganese oxide has low conductivity, and the effect of using a highly conductive π-conjugated conductive polymer is reduced.

 In addition, in the chemical oxidative polymerization method described in Patent Document 3 and the like, the polymerization time is long, and in order to ensure the thickness of the film, the polymerization must be repeated, resulting in low production efficiency of the capacitor. In addition, the conductivity was also lower than that of electrolytic polymerization. Furthermore, since the solution in the chemical oxidative polymerization method shows considerable acidity depending on the oxidizing agent, the dielectric layer as an oxide film is corroded, resulting in an increase in equivalent series resistance. Moreover, when it was going to manufacture a winding type aluminum electrolytic capacitor, there existed a problem that the separator made from the cellulose used conventionally could not be used. This is considered because the cellulose in a separator inhibits chemical oxidative polymerization.

As a method of forming a film of a π-conjugated conductive polymer other than the electrolytic polymerization method and the chemical oxidative polymerization method, water-soluble polyaniline is formed by chemical oxidative polymerization of aniline in the presence of a polyanion having a sulfo group, a carboxyl group, etc. A method of forming a coating film by preparing, applying and drying the aqueous polyaniline solution has been proposed (see Patent Document 4).
In addition, a method of forming a conductive coating by applying and drying a solution containing a π-conjugated conductive polymer, a polyanion, and a specific organic compound has been proposed (see Patent Document 5).
JP 2003-37024 A JP-A-63-158829 JP 63-173313 A JP-A-7-105718 Japanese Patent No. 2916098

However, according to the methods described in Patent Documents 4 and 5, a film having high conductivity (high electrical conductivity) can be easily formed, but the problem of corroding the dielectric layer has not been solved. Therefore, the equivalent series resistance of the capacitor could not be lowered.
An object of the present invention is to provide a capacitor having a low equivalent series resistance in which corrosion of a dielectric layer is prevented and a method for manufacturing the same.

The capacitor of the present invention includes an anode made of a porous body of valve metal, a dielectric layer formed by oxidizing the surface of the anode, and a cathode formed on the dielectric layer and including a solid electrolyte layer. In a capacitor having
The cathode solid electrolyte layer is formed by applying a conductive polymer solution containing a π-conjugated conductive polymer, a polyanion, and a solvent and having a pH adjusted to 3 to 13 at 25 ° C. It is characterized by.
In the capacitor of the present invention, it is preferable that the pH is adjusted to the above range by adding alkali to the conductive polymer solution.
In that case, the alkali is preferably a nitrogen-containing aromatic cyclic compound.
In the capacitor of the present invention, it is preferable that the conductive polymer solution contains a compound having one or more of a hydroxyl group, a glycidyl group, and an amino group in the molecule.
The manufacturing method of the valve capacitor of the present invention includes a π-conjugated system on a dielectric layer side surface in a capacitor intermediate body having an anode made of a metal porous body and a dielectric layer formed by oxidizing the surface of the anode. It comprises a step of applying and drying a conductive polymer solution containing a conductive polymer, a polyanion, and a solvent and having a pH adjusted to 3 to 13 at 25 ° C.

The capacitor of the present invention has a low equivalent series resistance because the corrosion of the dielectric layer is prevented. Furthermore, since the capacitor of the present invention prevents corrosion of the dielectric layer, the leakage current is small and the capacitance is high.
According to the method for manufacturing a capacitor of the present invention, corrosion of the dielectric layer can be prevented, and the equivalent series resistance of the capacitor can be lowered.

Hereinafter, an embodiment of a capacitor and a manufacturing method thereof according to the present invention will be described.
FIG. 1 is a diagram illustrating a configuration of a capacitor according to the present embodiment. The capacitor 10 includes an anode 11 made of a porous body of valve metal, a dielectric layer 12 formed by oxidizing the surface of the anode 11, and a cathode 13 formed on the dielectric layer 12. It is roughly structured.

<Anode>
Examples of the valve metal forming the anode 11 include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Of these, aluminum, tantalum, and niobium are preferable.
Specific examples of the anode 11 include those obtained by etching an aluminum foil to increase the surface area and then oxidizing the surface, or oxidizing the surface of a sintered body of tantalum particles and niobium particles into pellets. Can be mentioned. As for the thing processed in this way, the unevenness | corrugation is formed in the surface.

<Dielectric layer>
The dielectric layer 12 is formed by, for example, anodizing the surface of the metal anode 11 in an electrolytic solution such as an ammonium adipate aqueous solution. Therefore, as shown in FIG. 1, the surface of the dielectric layer 12 is uneven as in the anode 11.

<Cathode>
The cathode 13 includes a solid electrolyte layer 13a and a cathode metal layer 13b such as an aluminum foil formed on the solid electrolyte layer 13a. The solid electrolyte layer 13a includes a π-conjugated conductive polymer and a polyanion. And a conductive polymer solution containing a solvent is formed by coating.

(Π-conjugated conductive polymer)
The π-conjugated conductive polymer can be used as long as the main chain is an organic polymer having a π-conjugated system. Examples thereof include polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of easy polymerization and stability in air, polypyrroles, polythiophenes and polyanilines are preferred.
Even if the π-conjugated conductive polymer remains unsubstituted, sufficient conductivity can be obtained. However, in order to further increase the conductivity, an alkyl group, a carboxyl group, a sulfo group, an alkoxyl group, a hydroxyl group, a cyano group It is preferable to introduce a functional group such as a group into the π-conjugated conductive polymer.

  Specific examples of such π-conjugated conductive polymers include polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), and poly (3-n-propylpyrrole). ), Poly (3-butylpyrrole), poly (3-octylpyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4 Dibutylpyrrole), poly (3-carboxypyrrole), poly (3-methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl-4-carboxybutylpyrrole), Poly (3-hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly 3-hexyloxypyrrole), poly (3-methyl-4-hexyloxypyrrole), poly (3-methyl-4-hexyloxypyrrole), polythiophene, poly (3-methylthiophene), poly (3-ethylthiophene) , Poly (3-propylthiophene), poly (3-butylthiophene), poly (3-hexylthiophene), poly (3-heptylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-octadecylthiophene), poly (3-bromothiophene), poly (3-chlorothiophene), poly (3-iodothiophene), poly (3-cyanothiophene), poly (3 -Phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibuty) Ruthiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene), poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3-heptyl) Oxythiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3-octadecyloxythiophene), poly (3,4-dihydroxythiophene), Poly (3,4-dimethoxythiophene), poly (3,4-diethoxythiophene), poly (3,4-dipropoxythiophene), poly (3,4-dibutoxythiophene), poly (3,4-dihexyl) Oxythiophene), poly (3,4-diheptyloxythiophene), poly (3 4-dioctyloxythiophene), poly (3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylene) Dioxythiophene), poly (3,4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene), polyaniline, poly (2-methylaniline), poly (3 -Isobutylaniline), poly (2-anilinesulfonic acid), poly (3-anilinesulfonic acid), etc. It is below.

Among them, from one or two kinds selected from polypyrrole, polythiophene, poly (N-methylpyrrole), poly (3-methylthiophene), poly (3-methoxythiophene), and poly (3,4-ethylenedioxythiophene). The (co) polymer is preferably used from the viewpoints of resistance and reactivity. Furthermore, polypyrrole and poly (3,4-ethylenedioxythiophene) are more preferable because they have higher conductivity and improved heat resistance.
In addition, alkyl-substituted compounds such as poly (N-methylpyrrole) and poly (3-methylthiophene) are more preferable because solvent solubility and compatibility and dispersibility when a hydrophobic resin is added are further improved. . Further, among the alkyl groups of the alkyl-substituted compound, a methyl group is preferable because it prevents a decrease in conductivity.

The π-conjugated conductive polymer is obtained by chemical oxidative polymerization of a precursor monomer that forms a π-conjugated conductive polymer in a solvent in the presence of a suitable oxidizing agent and a polymer having an anionic group described below. Can be easily manufactured.
The precursor monomer has a π-conjugated system in the molecule, and a π-conjugated system is formed in the main chain even when polymerized by the action of an appropriate oxidizing agent. Examples thereof include pyrroles and derivatives thereof, thiophenes and derivatives thereof, anilines and derivatives thereof, and the like.
Specific examples of the precursor monomer include pyrrole, N-methylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, 3-octylpyrrole, 3-decylpyrrole, 3- Dodecylpyrrole, 3,4-dimethylpyrrole, 3,4-dibutylpyrrole, 3-carboxylpyrrole, 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, thiophene, 3 -Methylthiophene, 3-ethylthiophene, -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-hydroxythiophene, 3-methoxythiophene, 3-ethoxythiophene, 3-butoxythiophene, 3- Hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene, 3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyloxythiophene, 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-propylenedioxythiophene, 3,4-butene Oxythiophene, 3-methyl-4-methoxythiophene, 3-methyl-4-ethoxythiophene, 3-carboxythiophene, 3-methyl-4-carboxythiophene, 3-methyl-4-carboxyethylthiophene, 3-methyl-4 -Carboxybutylthiophene, aniline, 2-methylaniline, Examples include 3-isobutylaniline, 2-aniline sulfonic acid, and 3-aniline sulfonic acid.

  The solvent used in the production of the π-conjugated conductive polymer is not particularly limited as long as it is a solvent that can dissolve or disperse the precursor monomer and can maintain the oxidizing power of the oxidizing agent. . For example, polar solvents such as water, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylene phosphortriamide, acetonitrile, benzonitrile, cresol, phenol, xylenol, etc. Phenols, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone and methyl ethyl ketone, hydrocarbons such as hexane, benzene and toluene, carboxylic acids such as formic acid and acetic acid, ethylene carbonate, propylene carbonate, etc. Carbonate compounds, ether compounds such as dioxane, diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether Chain ethers such as polypropylene glycol dialkyl ether, 3-methyl-2-oxazolidinone heterocyclic compounds such as, acetonitrile, glutarodinitrile, methoxy acetonitrile, propionitrile, nitrile compounds such as benzonitrile and the like. These solvents may be used alone, as a mixture of two or more kinds, or as a mixture with other solvents.

  Any oxidizing agent may be used as long as it can oxidize the precursor monomer to obtain a π-conjugated conductive polymer. Examples thereof include ammonium peroxodisulfate (ammonium persulfate), sodium peroxodisulfate (persulfate). Sodium), peroxodisulfates such as potassium peroxodisulfate (potassium persulfate), transition metal compounds such as ferric chloride, ferric sulfate, ferric nitrate, cupric chloride, boron trifluoride Metal halide compounds such as aluminum chloride, metal oxides such as silver oxide and cesium oxide, peroxides such as hydrogen peroxide and ozone, organic peroxides such as benzoyl peroxide, oxygen, and the like.

(Polyanion)
The polyanion is a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, a substituted or unsubstituted polyester, and a copolymer thereof. It consists of a structural unit having a group and a structural unit having no anionic group.
The anion group of the polyanion functions as a dopant for the π-conjugated conductive polymer, and improves the conductivity and heat resistance of the π-conjugated conductive polymer.

  A polyalkylene is a polymer whose main chain is composed of repeating methylenes. Examples of the polyalkylene include polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly (3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polystyrene, and the like.

Polyalkenylene is a polymer composed of structural units containing one or more unsaturated bonds (vinyl groups) in the main chain. Specific examples of polyalkenylene include propenylene, 1-methylpropenylene, 1-butylpropenylene, 1-decylpropenylene, 1-cyanopropenylene, 1-phenylpropenylene, 1-hydroxypropenylene, 1-butenylene, 1-methyl-1-butenylene, 1-ethyl-1-butenylene, 1-octyl-1-butenylene, 1-pentadecyl-1-butenylene, 2-methyl-1-butenylene, 2-ethyl-1-butenylene, 2- Butyl-1-butenylene, 2-hexyl-1-butenylene, 2-octyl-1-butenylene, 2-decyl-1-butenylene, 2-dodecyl-1-butenylene, 2-phenyl-1-butenylene, 2-butenylene, 1-methyl-2-butenylene, 1-ethyl-2-butenylene, 1-octyl-2-butenylene 1-pentadecyl-2-butenylene, 2-methyl-2-butenylene, 2-ethyl-2-butenylene, 2-butyl-2-butenylene, 2-hexyl-2-butenylene, 2-octyl-2-butenylene, 2- Decyl-2-butenylene, 2-dodecyl-2-butenylene, 2-phenyl-2-butenylene, 2-propylenephenyl-2-butenylene, 3-methyl-2-butenylene, 3-ethyl-2-butenylene, 3-butyl 2-butenylene, 3-hexyl-2-butenylene, 3-octyl-2-butenylene, 3-decyl-2-butenylene, 3-dodecyl-2-butenylene, 3-phenyl-2-butenylene, 3-propylenephenyl- 2-butenylene, 2-pentenylene, 4-propyl-2-pentenylene, 4-butyl-2-pentenylene, 4-he Selected from sil-2-pentenylene, 4-cyano-2-pentenylene, 3-methyl-2-pentenylene, 4-ethyl-2-pentenylene, 3-phenyl-2-pentenylene, 4-hydroxy-2-pentenylene, hexenylene, etc. And a polymer containing one or more structural units.
Among these, substituted or unsubstituted butenylene is preferable because of the interaction between the unsaturated bond and the π-conjugated conductive polymer and the ease of synthesis using substituted or unsubstituted butadiene as a starting material.

Examples of polyimide include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2,3,3-tetracarboxydiphenyl ether dianhydride, 2,2- [4,4 Examples include polyimides from anhydrides such as' -di (dicarboxyphenyloxy) phenyl] propane dianhydride and diamines such as oxydianine, paraphenylenediamine, metaphenylenediamine, and benzophenonediamine.
Examples of the polyamide include polyamide 6, polyamide 6,6, polyamide 6,10 and the like.
Examples of the polyester include polyethylene terephthalate and polybutylene terephthalate.

When the polyanion has a substituent, examples of the substituent include an alkyl group, a hydroxyl group, an amino group, a carboxyl group, a cyano group, a phenyl group, a phenol group, an ester group, and an alkoxyl group. In view of solubility in a solvent, heat resistance, compatibility with a resin, and the like, an alkyl group, a hydroxyl group, a phenol group, and an ester group are preferable.
Alkyl groups can increase solubility and dispersibility in polar or nonpolar solvents, compatibility and dispersibility in resins, etc., and hydroxyl groups form hydrogen bonds with other hydrogen atoms and the like. It can be made easy, and the solubility in an organic solvent, the compatibility with a resin, the dispersibility, and the adhesiveness can be increased. In addition, the cyano group and the hydroxyphenyl group can increase the compatibility and solubility in the polar resin, and can also increase the heat resistance.
Among the above substituents, an alkyl group, a hydroxyl group, an ester group, and a cyano group are preferable.

Examples of the alkyl group include chain alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. . In consideration of solubility in an organic solvent, dispersibility in a resin, steric hindrance, and the like, an alkyl group having 1 to 12 carbon atoms is more preferable.
Examples of the hydroxyl group include a hydroxyl group directly bonded to the main chain of the polyanion or a hydroxyl group bonded via another functional group. Examples of other functional groups include an alkyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an amide group, and an imide group. Hydroxyl groups are substituted at the ends or in these functional groups. In these, the hydroxyl group couple | bonded with the terminal of the C1-C6 alkyl group couple | bonded with the principal chain is more preferable from the compatibility to resin and the solubility to an organic solvent.
Examples of the amino group include an amino group directly bonded to the main chain of the polyanion or an amino group bonded via another functional group. Examples of other functional groups include an alkyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an amide group, and an imide group. The amino group is substituted at the end or in these functional groups.
Examples of the phenol group include a phenol group directly bonded to the main chain of the polyanion or a phenol group bonded via another functional group. Examples of other functional groups include an alkyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an amide group, and an imide group. The phenol group is substituted at the end or in these functional groups.
Examples of the ester group include an alkyl ester group directly bonded to the main chain of the polyanion, an aromatic ester group, and an alkyl ester group or an aromatic ester group having another functional group interposed therebetween.
The cyano group includes a cyano group directly bonded to the main chain of the polyanion, a cyano group bonded to the terminal of the alkyl group having 1 to 7 carbon atoms bonded to the main chain of the polyanion, and 2 to 2 carbon atoms bonded to the main chain of the polyanion. And a cyano group bonded to the terminal of 7 alkenyl group.

  The anion group of the polyanion may be a functional group capable of undergoing chemical oxidation doping to the π-conjugated conductive polymer. Among these, from the viewpoint of ease of production and stability, a monosubstituted sulfate group, A monosubstituted phosphate group, a phosphate group, a carboxyl group, a sulfo group and the like are preferable. Furthermore, from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer, a sulfo group, a monosubstituted sulfate group, and a carboxyl group are more preferable.

Specific examples of the polyanion include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly (2-acrylamide- 2-methylpropanesulfonic acid), polyisoprenesulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly (2-acrylamido-2-methylpropane carboxylic acid), Examples include polyisoprene carboxylic acid and polyacrylic acid. These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient.
Among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethyl sulfonic acid, and polyacrylic acid butyl sulfonic acid are preferable. These polyanions can mitigate thermal decomposition of the π-conjugated conductive polymer.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

Examples of methods for producing polyanions include a method of directly introducing an anionic group into a polymer having no anionic group using an acid, a method of sulfonating a polymer having no anionic group with a sulfonating agent, and anionic group-containing polymerization. And a method of production by polymerization of a functional monomer.
Examples of the method for producing an anion group-containing polymerizable monomer by polymerization include a method for producing an anion group-containing polymerizable monomer in a solvent by oxidative polymerization or radical polymerization in the presence of an oxidizing agent and / or a polymerization catalyst. Specifically, a predetermined amount of the anionic group-containing polymerizable monomer is dissolved in a solvent, kept at a constant temperature, and a solution in which a predetermined amount of an oxidizing agent and / or a polymerization catalyst is dissolved in the solvent is added to the predetermined amount. React with time. The polymer obtained by the reaction is adjusted to a certain concentration by the solvent. In this production method, an anionic group-containing polymerizable monomer may be copolymerized with a polymerizable monomer having no anionic group.
The oxidizing agent and solvent used in the polymerization of the anionic group-containing polymerizable monomer are the same as those used in the polymerization of the precursor monomer that forms the π-conjugated conductive polymer.
When the obtained polymer is a polyanionic salt, it is preferably transformed into a polyanionic acid. Examples of the method for converting to an anionic acid include an ion exchange method using an ion exchange resin, a dialysis method, an ultrafiltration method, and the like. Among these, the ultrafiltration method is preferable from the viewpoint of easy work.

The anionic group-containing polymerizable monomer is one in which a part of the monomer is substituted with a monosubstituted sulfate group, a carboxyl group, a sulfo group, etc., for example, a substituted or unsubstituted ethylene sulfonic acid compound, a substituted or unsubstituted Styrene sulfonic acid compound, substituted or unsubstituted acrylate sulfonic acid compound, substituted or unsubstituted methacrylate sulfonic acid compound, substituted or unsubstituted acrylamide sulfonic acid compound, substituted or unsubstituted cyclovinylene sulfonic acid compound, substituted or unsubstituted And a substituted or unsubstituted vinyl aromatic sulfonic acid compound.
Specifically, vinyl sulfonic acid and salts thereof, allyl sulfonic acid and salts thereof, methallyl sulfonic acid and salts thereof, styrene sulfonic acid, methallyloxybenzene sulfonic acid and salts thereof, allyloxybenzene sulfonic acid and salts thereof, α-methylstyrenesulfonic acid and its salts, acrylamide-t-butylsulfonic acid and its salts, 2-acrylamido-2-methylpropanesulfonic acid and its salts, cyclobutene-3-sulfonic acid and its salts, isoprenesulfonic acid and its Salts, 1,3-butadiene-1-sulfonic acid and its salts, 1-methyl-1,3-butadiene-2-sulfonic acid and its salts, 1-methyl-1,3-butadiene-4-sulfonic acid and its salts, ethyl acrylate sulfonic acid _{(CH 2 CH-COO- (CH} 2 ₂ -SO ₃ H) and its salts, acrylic acid propyl sulfonic acid _{(CH 2 CH-COO- (CH} 2) 3 -SO 3 H) and its salts, acrylic acid -t- butyl sulfonic acid _(CH 2 _{CH-COO -C (CH 3) 2 CH 2} -SO 3 H) and its salts, acrylic acid -n- butyl sulfonic acid _{(CH 2 CH-COO- (CH} 2) 4 -SO 3 H) and salts thereof, ethyl allyl acid sulfonic acid _{(CH 2 CHCH 2 -COO- (CH} 2) 2 -SO 3 H) and its salts, allyl acid -t- butyl sulfonic acid _{(CH 2 CHCH 2 -COO-C} (CH 3) 2 CH 2 -SO ₃ H) and salts thereof, 4-pentenoic acid ethylsulfonic acid (CH ₂ CH (CH ₂ ) ₂ —COO— (CH ₂ ) ₂ —SO ₃ H) and salts thereof, 4-pentenoic acid propyl sulfonic acid (CH ₂ CH (CH ₂ ) ₂ —COO— (CH ₂ ) ₃ -SO ₃ H) and salts thereof, 4-pentenoic acid-n-butylsulfonic acid (CH ₂ CH (CH ₂ ) ₂ —COO— (CH ₂ ) ₄ —SO ₃ H) and salts thereof, 4-pentene Acid-t-butyl sulfonic acid (CH ₂ CH (CH ₂ ) ₂ —COO—C (CH ₃ ) ₂ CH ₂ —SO ₃ H) and its salts, 4-pentenoic acid phenylene sulfonic acid (CH ₂ CH (CH _{2 2} ) -COO—C ₆ H ₄ —SO ₃ H) and salts thereof, 4-pentenoic acid naphthalenesulfonic acid (CH ₂ CH (CH ₂ ) ₂ —COO—C ₁₀ H ₈ —SO ₃ H) and salts thereof, Ethyl methacrylate sulfonic acid (CH ₂ C (CH ₃ ) —COO— (CH ₂ ) ₂ —SO ₃ H) and salts thereof, propyl methacrylate methacrylate (CH ₂ C (CH ₃ ) —COO— (CH ₂ ) ₃ -SO ₃ H) and its salts, methacrylic acid-t-butylsulfate Acid _{(CH 2 C (CH 3)} -COO-C (CH 3) 2 CH 2 -SO 3 H) and its salts, methacrylic acid -n- butyl sulfonic acid _{(CH 2 C (CH 3)} -COO- ( CH ₂ ) ₄ —SO ₃ H) and salts thereof, phenylene sulfonic acid methacrylate (CH ₂ C (CH ₃ ) —COO—C ₆ H ₄ —SO ₃ H) and salts thereof, naphthalene sulfonic acid methacrylate (CH ₂₎ C (CH ₃ ) —COO—C ₁₀ H ₈ —SO ₃ H) and salts thereof, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly-2-acrylamide— Examples include 2-methylpropanecarboxylic acid, polyisoprene carboxylic acid, polyacrylic acid and the like. Moreover, the copolymer containing 2 or more types of these may be sufficient.

Examples of the polymerizable monomer having no anionic group include ethylene, propene, 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, styrene, p-methylstyrene, p. -Ethylstyrene, p-butylstyrene, 2,4,6-trimethylstyrene, p-methoxystyrene, α-methylstyrene, 2-vinylnaphthalene, 6-methyl-2-vinylnaphthalene, 1-vinylimidazole, vinylpyridine, Vinyl acetate, acrylaldehyde, acrylonitrile, N-vinyl-2-pyrrolidone, N-vinylacetamide, N-vinylformamide, N-vinylimidazole, acrylamide, N, N-dimethylacrylamide, acrylic acid, methyl acrylate, Ethyl acrylate, propyl acrylate, acrylic acid -Butyl, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, isononyl butyl acrylate, lauryl acrylate, allyl acrylate, stearyl acrylate, isobornyl acrylate, cyclohexyl acrylate, benzyl acrylate, ethyl acrylate Carbitol, phenoxyethyl acrylate, hydroxyethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, methoxybutyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl T-butyl acid, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, methacrylic acid Benzyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acryloylmorpholine, vinylamine, N, N-dimethylvinylamine, N, N-diethylvinylamine, N, N-dibutylvinylamine, N, N-di -T-butylvinylamine, N, N-diphenylvinylamine, N-vinylcarbazole, vinyl alcohol, vinyl chloride, vinyl fluoride, methyl vinyl ether, ethyl vinyl ether, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, 2-methylcyclohexene, vinylphenol, 1,3-butadiene, 1-methyl-1,3-butadiene, 2-methyl-1,3-butadiene, 1,4-dimethyl-1,3-butadiene, 1,2- Dimethyl , 3-butadiene, 1,3-dimethyl-1,3-butadiene, 1-octyl-1,3-butadiene, 2-octyl-1,3-butadiene, 1-phenyl-1,3-butadiene, 2-phenyl -1,3-butadiene, 1-hydroxy-1,3-butadiene, 2-hydroxy-1,3-butadiene and the like.
Solvent solubility can be controlled by copolymerizing these polymerizable monomers having no anionic group.

  The ratio of the π-conjugated conductive polymer and the polyanion in the conductive polymer solution is preferably 1 to 1000 parts by mass of the π-conjugated conductive polymer with respect to 100 parts by mass of the polyanion. When the π-conjugated conductive polymer is less than 1 part by mass, the conductivity tends to be insufficient, and when it exceeds 1000 parts by mass, the solvent solubility tends to be insufficient.

(Dopant)
In the conductive polymer solution, the polyanion functions as a dopant for the π-conjugated conductive polymer, but the conductive polymer solution may contain a dopant other than the polyanion (hereinafter referred to as other dopant). .
Other dopants may be donor or acceptor as long as the π-conjugated conductive polymer can be oxidized and reduced.

[Donor dopant]
Examples of the donor dopant include alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, methyltriethylammonium, dimethyldiethylammonium, and the like. A quaternary amine compound etc. are mentioned.

[Acceptor dopant]
As the acceptor dopant, for example, a halogen compound, Lewis acid, proton acid, organic cyano compound, organometallic compound, fullerene, hydrogenated fullerene, hydroxylated fullerene, carboxylated fullerene, sulfonated fullerene, or the like can be used.
Furthermore, examples of the halogen compound include chlorine (Cl ₂ ), bromine (Br ₂ ), iodine (I ₂ ), iodine chloride (ICl), iodine bromide (IBr), and iodine fluoride (IF). .
Examples of the Lewis acid include PF ₅ , AsF ₅ , SbF ₅ , BF ₅ , BCl ₅ , BBr ₅ , SO _{3 and the} like.
As the organic cyano compound, a compound containing two or more cyano groups in a conjugated bond can be used. Examples include tetracyanoethylene, tetracyanoethylene oxide, tetracyanobenzene, dichlorodicyanobenzoquinone (DDQ), tetracyanoquinodimethane, and tetracyanoazanaphthalene.

  Examples of the protonic acid include inorganic acids and organic acids. Furthermore, examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, borohydrofluoric acid, hydrofluoric acid, and perchloric acid. Examples of the organic acid include organic carboxylic acids, phenols, and organic sulfonic acids.

  As the organic carboxylic acid, aliphatic, aromatic, cycloaliphatic or the like containing one or more carboxyl groups can be used. For example, formic acid, acetic acid, oxalic acid, benzoic acid, phthalic acid, maleic acid, fumaric acid, malonic acid, tartaric acid, citric acid, lactic acid, succinic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, nitroacetic acid, And triphenylacetic acid.

As the organic sulfonic acid, aliphatic, aromatic, cycloaliphatic or the like containing one or more sulfo groups, or a polymer containing sulfo groups can be used.
As one containing one sulfo group, for example, methanesulfonic acid, ethanesulfonic acid, 1-propanesulfonic acid, 1-butanesulfonic acid, 1-hexanesulfonic acid, 1-heptanesulfonic acid, 1-octanesulfonic acid, 1 -Nonanesulfonic acid, 1-decanesulfonic acid, 1-dodecanesulfonic acid, 1-tetradecanesulfonic acid, 1-pentadecanesulfonic acid, 2-bromoethanesulfonic acid, 3-chloro-2-hydroxypropanesulfonic acid, trifluoromethanesulfone Acid, trifluoroethanesulfonic acid, colistin methanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, aminomethanesulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 2-amino-5-naphthol- 7-sulfonic acid, 3-aminopropanesulfone N-cyclohexyl-3-aminopropanesulfonic acid, benzenesulfonic acid, alkylbenzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, ethylbenzenesulfonic acid, propylbenzenesulfonic acid, butylbenzenesulfonic acid, pentylbenzenesulfonic acid, hex Tylbenzenesulfonic acid, heptylbenzenesulfonic acid, octylbenzenesulfonic acid, nonylbenzenesulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, 2, 4-dimethylbenzenesulfonic acid, dipropylbenzenesulfonic acid, 4-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid 4-amino-2-chlorotoluene-5-sulfonic acid, 4-amino-3-methylbenzene-1-sulfonic acid, 4-amino-5-methoxy-2-methylbenzenesulfonic acid, 2-amino-5-methyl Benzene-1-sulfonic acid, 4-amino-2-methylbenzene-1-sulfonic acid, 5-amino-2-methylbenzene-1-sulfonic acid, 4-amino-3-methylbenzene-1-sulfonic acid, 4 -Acetamide-3-chlorobenzenesulfonic acid, 4-chloro-3-nitrobenzenesulfonic acid, p-chlorobenzenesulfonic acid, naphthalenesulfonic acid, methylnaphthalenesulfonic acid, propylnaphthalenesulfonic acid, butylnaphthalenesulfonic acid, pentylnaphthalenesulfonic acid, 4 -Amino-1-naphthalenesulfonic acid, 8-chloronaphthalene-1- Examples include sulfonic acid, naphthalene sulfonic acid formalin polycondensate, melamine sulfonic acid formalin polycondensate, anthraquinone sulfonic acid, and pyrene sulfonic acid. These metal salts can also be used.

  Examples of those containing two or more sulfo groups include ethanedisulfonic acid, butanedisulfonic acid, pentanedisulfonic acid, decanedisulfonic acid, o-benzenedisulfonic acid, m-benzenedisulfonic acid, p-benzenedisulfonic acid, and toluenedisulfonic acid. Xylene disulfonic acid, chlorobenzene disulfonic acid, fluorobenzene disulfonic acid, dimethylbenzene disulfonic acid, diethylbenzene disulfonic acid, aniline-2,4-disulfonic acid, aniline-2,5-disulfonic acid, 3,4-dihydroxy-1,3 -Benzenedisulfonic acid, naphthalene disulfonic acid, methyl naphthalene disulfonic acid, ethyl naphthalene disulfonic acid, pentadecyl naphthalene disulfonic acid, 3-amino-5-hydroxy-2,7-naphthalene disulfonic acid, 1- Cetamide-8-hydroxy-3,6-naphthalenedisulfonic acid, 2-amino-1,4-benzenedisulfonic acid, 1-amino-3,8-naphthalenedisulfonic acid, 3-amino-1,5-naphthalenedisulfonic acid, 8-amino-1-naphthol-3,6-disulfonic acid, 4-amino-5-naphthol-2,7-disulfonic acid, 4-acetamido-4'-isothio-cyanotostilbene-2,2'-disulfonic acid 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid, 4-acetamido-4′-maleimidylstilbene-2,2′-disulfonic acid, naphthalenetrisulfonic acid, dinaphthylmethanedisulfone An acid, anthraquinone disulfonic acid, anthracene sulfonic acid, etc. are mentioned. These metal salts can also be used.

(solvent)
Examples of the solvent contained in the conductive polymer solution include water and / or an organic solvent. The organic solvent is not particularly limited. For example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N-vinyl Polar solvents such as formamide and N-vinylacetamide, phenols such as cresol, phenol and xylenol, alcohols such as methanol, ethanol, propanol and butanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1 , 3-butylene glycol, 1,4-butylene glycol, glycerin, diglycerin, D-glucose, D-glucitol, isoprene glycol, butanediol, 1,5-penta Polyols such as diol, 1,6-hexanediol, 1,9-nonanediol and neopentyl glycol, ketones such as acetone and methyl ethyl ketone, hydrocarbons such as hexane, benzene and toluene, formic acid and acetic acid Carboxylic acids such as, carbonate compounds such as ethylene carbonate and propylene carbonate, ether compounds such as dioxane and diethyl ether, chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, Heterocyclic compounds such as 3-methyl-2-oxazolidinone, acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, etc. Nitrile compounds, and the like. These solvents may be used alone, as a mixture of two or more kinds, or as a mixture with other solvents.
Since the organic solvent interacts with the π-conjugated conductive polymer and the polyanion and has an effect of further increasing the electrical conductivity of the solid electrolyte, it is preferably contained in the conductive polymer solution.
As the solvent contained in the conductive polymer solution, the solvent used in producing the polyanion or the π-conjugated conductive polymer may be used as it is, or may be newly added.

  Among the above organic solvents, since the polyanion is often water-soluble, a solvent that can be mixed with water is preferable. Furthermore, since it is easier to interact with the π-conjugated conductive polymer and the polyanion and the electric conductivity of the fixed electrolyte layer is higher, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N Preferred are polar solvents such as dimethylacetamide, dimethylsulfoxide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, polyhydric alcohols, and chain ethers.

(PH of conductive polymer solution)
The conductive polymer solution is adjusted so that the pH at 25 ° C. is 3 to 13, preferably 5 to 11. If the pH is less than 3, the acidity is too strong to prevent corrosion of the dielectric layer 12 and the cathode metal layer 13b, and if it exceeds 13, the polyanion is dedope and the conductivity of the solid electrolyte layer 13a is increased. Run short.
Examples of the method for adjusting the pH include a method of forming an acid and a salt by adding an alkali to an aqueous solution of a complex of a π-conjugated conductive polymer and a polyanion (hereinafter referred to as an aqueous complex solution), a polyanion And a method of esterifying the acid group and a method of amidating the acid group.
As long as an alkali can be added to form an acid and a salt, ester, or amide, the alkali treatment method and procedure are not particularly limited. When no other additive is added, the pH can be easily adjusted simply by adding an alkali to the conductive polymer solution.
When adding other additives, the method of adjusting the pH with an alkali after adding the other additive, the method of adding the other additive after adjusting the pH with an alkali, the pH adjustment with an alkali, A method of simultaneously adding other additives can be applied.
Here, in the method of adjusting the pH after adding other additives, the pH can be adjusted with high accuracy and can be easily adjusted to a predetermined pH.
In the method of adding other additives after adding alkali, the electrical conductivity of the conductive polymer that has been changed by adjusting the pH can be adjusted by adding other additives, so that the conductivity can be easily adjusted. .
In the method in which pH adjustment with alkali and addition of other additives are performed simultaneously, the operation can be simplified.

When adding an alkali, it is not specifically limited as an alkali, A well-known inorganic alkali and organic alkali can be used. Examples of the inorganic alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia and the like. Examples of the organic alkali include aliphatic amines such as ethylamine, diethylamine, methylethylamine and triethylamine, aromatic amines such as aniline, benzylamine, pyrrole, imidazole and pyridine, or derivatives thereof, N-methyl-pyrrolidone. N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide and other nitrogen-containing compounds, sodium methoxide, sodium ethoxide, etc. Examples thereof include metal alkoxides such as sodium alkoxide, potassium alkoxide and calcium alkoxide, and dimethyl sulfoxide.
Among these, weakly basic aliphatic amines, aromatic amines, and metal alkoxides are preferable.

Furthermore, a nitrogen-containing aromatic cyclic compound can be suitably used as the organic alkali. The nitrogen-containing aromatic cyclic compound can not only prevent de-doping of the polyanion, but can also improve conductivity.
Here, the nitrogen-containing aromatic cyclic compound has an aromatic ring containing at least one nitrogen atom, and the nitrogen atom in the aromatic ring is conjugated with other atoms in the aromatic ring. It has a relationship. In order to become a conjugated relationship, the nitrogen atom and other atoms form an unsaturated bond. Alternatively, even if the nitrogen atom does not directly form an unsaturated bond with another atom, it may be adjacent to the other atom that forms the unsaturated bond. This is because an unshared electron pair existing on a nitrogen atom can form a pseudo conjugate relationship with an unsaturated bond formed between other atoms.
The nitrogen-containing aromatic cyclic compound preferably has both a nitrogen atom having a conjugated relationship with another atom and a nitrogen atom adjacent to the other atom forming the unsaturated bond.

Examples of such nitrogen-containing aromatic cyclic compounds include pyridines and derivatives thereof containing one nitrogen atom, imidazoles and derivatives thereof containing two nitrogen atoms, pyrimidines and derivatives thereof, and pyrazines. And derivatives thereof, triazines containing three nitrogen atoms, and derivatives thereof. From the viewpoint of solvent solubility and the like, pyridines and derivatives thereof, imidazoles and derivatives thereof, and pyrimidines and derivatives thereof are preferable.
The nitrogen-containing aromatic cyclic compound may be one in which a substituent such as an alkyl group, a hydroxyl group, a carboxyl group, a cyano group, a phenyl group, a phenol group, an ester group, an alkoxyl group, or a carbonyl group is introduced into the ring. It may be good or not introduced. The ring may be polycyclic.

Among the substituents, the alkyl group includes alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. Can be mentioned. Among these, in view of solubility in an organic solvent, dispersibility in a resin, steric hindrance, and the like, an alkyl group having 1 to 12 carbon atoms is preferable.
Examples of the hydroxyl group include hydroxy, methylene hydroxy, ethylene hydroxy, trimethylene hydroxy, tetramethylene hydroxy, pentamethylene hydroxy, hexamethylene hydroxy, heptamethylene hydroxy, propylene hydroxy, butylene hydroxy, ethylmethylene hydroxy and other alkylene hydroxyl groups, propenylene Alkenylene hydroxyl groups such as hydroxy, butenylene hydroxy, pentenylene hydroxy and the like can be mentioned.
Examples of the carboxyl group include carboxy, methylene carboxy, ethylene carboxy, trimethylene carboxy, propylene carboxy, tetramethylene carboxy, pentamethylene carboxy, hexamethylene carboxy, heptamethyl carboxy, ethyl methylene carboxy, phenylethylene carboxy, and other alkylene carboxy and isoprene carboxy. And alkenylene carboxyl groups such as propenylene carboxy, butenylene carboxy, and pentenylene carboxy.

Examples of the cyano group include alkylene cyano groups such as cyano, methylene cyano, ethylene cyano, trimethylene cyano, tetramethylene cyano, pentamethylene cyano, hexamethylene cyano, heptamethylene cyano, propylene cyano, butylene cyano, ethyl methylene cyano, and propenylene. Examples include alkenylene cyano groups such as cyano, butenylene cyano, and pentenylene cyano.
Examples of the phenol group include alkylphenol groups such as phenol, methylphenol, ethylphenol and butylphenol, and alkylenephenol groups such as methylenephenol, ethylenephenol, trimethylenephenol, tetramethylenephenol, pentamethylenephenol and hexamethylenephenol.
Examples of the phenyl group include alkylphenyl groups such as phenyl, methylphenyl, butylphenyl, octylphenyl, and dimethylphenyl, and methylenephenyl, ethylenephenyl, trimethylenephenyl, tetramethylenephenyl, pentamethylenephenyl, hexamethylenephenyl, and heptamethylene. Examples thereof include alkylenephenyl groups such as phenyl, and alkenylenephenyls such as propenylenephenyl, butenylenephenyl, and pentenylenephenyl.
Examples of the alkoxyl group include methoxy, ethoxy, butoxy, phenoxy and the like.

  Specific examples of pyridines and derivatives thereof include pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine, 2,4,6-trimethylpyridine. , 3-cyano-5-methylpyridine, 2-pyridinecarboxylic acid, 6-methyl-2-pyridinecarboxylic acid, 2,6-pyridine-dicarboxylic acid, 4-pyridinecarboxaldehyde, 4-aminopyridine, 2,3- Diaminopyridine, 2,6-diaminopyridine, 2,6-diamino-4-methylpyridine, 4-hydroxypyridine, 2,6-dihydroxypyridine, methyl 6-hydroxynicotinate, 2-hydroxy-5-pyridinemethanol, 6 -Ethyl hydroxynicotinate, 4-pyridinemethanol, 4-pyridineethanol, 2-phenylpyridine, 3-methylquinoline, 3-ethylquinoline, quinolinol, 2,3-cyclopentenopyridine, 2,3-cyclohexanopyridine, 1,2-di (4-pyridyl) ethane, 1,2- Di (4-pyridyl) propane, 2-pyridinecarboxaldehyde, 2-pyridinecarboxylic acid, 2-pyridinecarbonitrile, 2,3-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, Examples include 2,6-pyridinedicarboxylic acid and 3-pyridinesulfonic acid.

  Specific examples of imidazoles and derivatives thereof include imidazole, 2-methylimidazole, 2-propylimidazole, 2-undecylimidazole, 2-phenylimidazole, N-methylimidazole, 1- (2-hydroxyethyl) imidazole. 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2- Ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 1-acetylimidazole, 4,5-imidazole dicarboxylic acid, dimethyl 4,5-imidazole dicarboxylate, benzimidazole, 2-aminobenz Imidazole, 2-amino-base lens imidazole-2-sulfonic acid, 2-amino-1-methyl-base lens imidazole, 2-hydroxy-base lens imidazole, 2- (2-pyridyl) base lens and imidazole.

  Specific examples of pyrimidines and derivatives thereof include 2-amino-4-chloro-6-methylpyrimidine, 2-amino-6-chloro-4-methoxypyrimidine, 2-amino-4,6-dichloropyrimidine, 2-amino-4,6-dihydroxypyrimidine, 2-amino-4,6-dimethylpyrimidine, 2-amino-4,6-dimethoxypyrimidine, 2-aminopyrimidine, 2-amino-4-methylpyrimidine, 4,6 -Dihydroxypyrimidine, 2,4-dihydroxypyrimidine-5-carboxylic acid, 2,4,6-triaminopyrimidine, 2,4-dimethoxypyrimidine, 2,4,5-trihydroxypyrimidine, 2,4-pyrimidinediol, etc. Is mentioned.

  Specific examples of the pyrazines and derivatives thereof include pyrazine, 2-methylpyrazine, 2,5-dimethylpyrazine, pyrazinecarboxylic acid, 2,3-pyrazinedicarboxylic acid, 5-methylpyrazinecarboxylic acid, pyrazineamide, 5 -Methylpyrazineamide, 2-cyanopyrazine, aminopyrazine, 3-aminopyrazine-2-carboxylic acid, 2-ethyl-3-methylpyrazine, 2-ethyl-3-methylpyrazine, 2,3-dimethylpyrazine, 2, Examples include 3-diethylpyrazine.

  Specific examples of triazines and derivatives thereof include 1,3,5-triazine, 2-amino-1,3,5-triazine, 3-amino-1,2,4-triazine, and 2,4-diamino. -6-phenyl-1,3,5-triazine, 2,4,6-triamino-1,3,5-triazine, 2,4,6-tris (trifluoromethyl) -1,3,5-triazine, 2,4,6-tri-2-pyridine-1,3,5-triazine, 3- (2-pyridine) -5,6-bis (4-phenylsulfonic acid) -1,2,4-triazine disodium 3- (2-pyridine) -5,6-diphenyl-1,2,4-triazine, 3- (2-pyridine) -5,6-diphenyl-1,2,4-triazine-ρ, ρ′- Disodium disulphonate, 2-hydroxy-4,6-dichloro -1,3,5-triazine and the like.

Since a non-shared electron pair exists in the nitrogen atom in the nitrogen-containing aromatic cyclic compound, a substituent or a proton is easily coordinated or bonded on the nitrogen atom. When a substituent or proton is coordinated or bonded to a nitrogen atom, it tends to have a cationic charge on the nitrogen atom. Here, since the nitrogen atom and other atoms have a conjugated relationship, the cation charge generated by the coordination or bonding of a substituent or a proton on the nitrogen atom is contained in the nitrogen-containing aromatic ring. Once diffused, it will exist in a stable form.
For this reason, in the nitrogen-containing aromatic cyclic compound, a substituent may be introduced into the nitrogen atom to form a nitrogen-containing aromatic cyclic compound cation. Further, a salt may be formed by combining the cation and the anion. Even if it is a salt, the same effect as a nitrogen-containing aromatic cyclic compound which is not a cation is exhibited.

Examples of the substituent introduced into the nitrogen atom of the nitrogen-containing aromatic cyclic compound include hydrogen, alkyl group, hydroxyl group, carboxyl group, cyano group, phenyl group, phenol group, ester group, alkoxyl group, carbonyl group and the like. Can be mentioned.
Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. In consideration of solubility in an organic solvent, dispersibility in a resin, steric hindrance, and the like, an alkyl group having 1 to 12 carbon atoms is more preferable.
Examples of the hydroxyl group include hydroxy, methylene hydroxy, ethylene hydroxy, trimethylene hydroxy, tetramethylene hydroxy, pentamethylene hydroxy, hexamethylene hydroxy, heptamethylene hydroxy, propylene hydroxy, butylene hydroxy, ethylmethylene hydroxy and other alkylene hydroxyl groups, propenylene Alkenylene hydroxyl groups such as hydroxy, butenylene hydroxy, pentenylene hydroxy and the like can be mentioned.
Examples of the carboxyl group include carboxy, methylene carboxy, ethylene carboxy, trimethylene carboxy, propylene carboxy, tetramethylene carboxy, pentamethylene carboxy, hexamethylene carboxy, heptamethylene carboxy, ethyl methylene carboxy, phenyl ethylene carboxy, and the like, isoprene Examples include alkenylene carboxyl groups such as carboxy, propenylene carboxy, butenylene carboxy, and pentenylene carboxy.

Examples of the cyano group include alkylene cyano groups such as cyano, methylene cyano, ethylene cyano, trimethylene cyano, tetramethylene cyano, pentamethylene cyano, hexamethylene cyano, heptamethylene cyano, propylene cyano, butylene cyano, and ethyl methylene cyano, and propylene. Alkenylene cyano groups such as nylene cyano, butenylene cyano, pentenylene cyano and the like can be mentioned.
Examples of the phenol group include alkylphenol groups such as phenol, methylphenol, ethylphenol, and butylphenol, and alkylenephenol groups such as methylenephenol, ethylenephenol, trimethylenephenol, tetramethylenephenol, pentamethylenephenol, and hexamethylenephenol. .
Examples of the phenyl group include alkylphenyl groups such as phenyl, methylphenyl, butylphenyl, octylphenyl, dimethylphenyl, methylenephenyl, ethylenephenyl, trimethylenephenyl, tetramethylenephenyl, pentamethylenephenyl, hexamethylenephenyl, heptamethylenephenyl, etc. And alkenylene phenyl such as propenylene phenyl, butenylene phenyl, and pentenylene phenyl.
Examples of the alkoxyl group include methoxy, ethoxy, butoxy, phenoxy and the like.

  When such an alkali is contained in the conductive polymer solution, the electrical conductivity of the solid electrolyte layer 13a formed by applying the conductive polymer solution can be improved.

  When the capacitor 10 is used in an electric circuit, a sufficiently low equivalent series resistance (ESR) is required. The ESR of a capacitor is often governed by various factors such as the electrical conductivity of the solid electrolyte layer 13a, the electrode occupation area, and the denseness of the solid electrolyte layer 13a. In particular, the electric conductivity of the solid electrolyte layer 13a greatly affects the ESR of the capacitor 10, and at least the electric conductivity of the solid electrolyte layer 13a is required to lower the ESR of the capacitor 10. Accordingly, the electrical conductivity of the solid electrolyte layer 13a is preferably 1 S / cm or more, more preferably 10 S / cm or more, and particularly preferably 50 S / cm or more.

  In order to increase the electrical conductivity of the solid electrolyte layer 13a (to 1 S / cm or more), a method in which an alkali treatment is performed on the conductive polymer solution to add an alkali, a hydroxyl group, a glycidyl group in the molecule, The method of adding the compound which has any 1 or more types of an amino group is mentioned. In addition, as a method for increasing the electrical conductivity of the solid electrolyte layer 13a, a method in which the above organic solvent is contained in a conductive polymer solution may be employed.

Examples of the compound having a hydroxyl group in the molecule include aliphatic alcohols such as methanol, ethanol, propanol, trichloroethanol, trifluoroethanol, hydroxyethyl acrylate, and hydroxyethyl acrylamide, benzyl alcohol, phenol, hydroquinone, pyrogallol, resorcinol, Aromatic alcohols such as pyrocatechol, phenolic hydroxyl group-containing compounds, amino alcohols such as ethanolamine, diethanolamine, and triethanolamine can be used. When a compound having a hydroxyl group in the molecule is added, the acid group can be esterified.
Examples of the compound having a glycidyl group in the molecule include ethyl glycidyl ether, butyl glycidyl ether, t-butyl glycidyl ether, allyl glycidyl ether, benzyl glycidyl ether, glycidyl phenyl ether, bisphenol A, diglycidyl ether, and glycidyl methacrylate methacrylate. And the like. Even when a compound having a glycidyl group in the molecule is added, the acid group can be esterified.
Examples of the compound having an amino group include amine compounds such as amino alcohols, ethylamine, aniline, and benzylamine. When a compound having an amino group in the molecule is added, the acid group can be amidated.

  Among these, an aliphatic alcohol or a phenolic hydroxyl group-containing compound is preferable because the conductivity of the π-conjugated conductive polymer can be further improved. Furthermore, a phenolic hydroxyl group-containing compound is particularly preferable because it has an antioxidant function and can improve heat resistance and long-term stability. In addition, compounds with acrylic groups such as hydroxyethyl acrylamide and hydroxyethyl acrylate can crosslink π-conjugated conductive polymers when used in combination with light or initiators, improving thermal and mechanical properties. It is preferable at the point which can be made.

In the capacitor 10 described above, the solid electrolyte layer 13a of the cathode 13 includes a π-conjugated conductive polymer, a dopant, and a nitrogen-containing aromatic cyclic compound, and the pH is adjusted to 3 to 13. It is formed by applying a solution. That is, since the solid electrolyte layer 13a is formed from a conductive polymer solution having a weak acidity, corrosion of the dielectric layer 12 can be prevented, and the equivalent series resistance can be reduced. Further, if the conductive polymer solution is subjected to an alkali treatment, the electrical conductivity of the solid electrolyte layer 13a is increased, so that the equivalent series resistance can be further increased.
Further, since the solid electrolyte layer 13a is formed of the conductive polymer solution and the dielectric layer is prevented from corroding, the capacitor 10 has a small leakage current and a high capacitance.

(Capacitor manufacturing method)
Next, a method for manufacturing the capacitor of the present invention will be described.
In the method for producing a capacitor according to the present invention, the surface of the capacitor intermediate having the anode made of a porous body of the valve metal and the dielectric layer of the oxide film formed by oxidizing the surface of the anode has a pH on the surface. The conductive polymer solution adjusted to 3 to 13 is applied to form a solid electrolyte layer.
Examples of the method for applying the conductive polymer solution include known methods such as coating, dipping, and spraying. Examples of the drying method include known methods such as hot air drying.

After the solid electrolyte layer is formed, the cathode can be formed by impregnating the electrolyte solution as necessary and then applying a carbon paste or a silver paste. Alternatively, the separator can be impregnated with carbon paste or silver paste to form the cathode.
As the separator, single or mixed nonwoven fabric such as cellulose fiber, glass fiber, polypropylene fiber, polyester fiber, polyamide fiber, carbonized nonwoven fabric obtained by carbonizing these, or the like is used.

 In the capacitor manufacturing method described above, the conductive polymer solution whose pH at 25 ° C. is adjusted to 3 to 13 is applied to the surface of the dielectric layer to form the solid electrolyte layer, so that corrosion of the dielectric layer can be prevented. As a result, the equivalent series resistance of the capacitor can be reduced.

Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
(1) Preparation of conductive polymer solution 14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene and 27.5 g (0.15 mol) of polystyrene sulfonic acid (molecular weight: about 150,000) The solution dissolved in ion-exchanged water was mixed at 20 ° C.
29.64 g (0.13 mol) of ammonium persulfate and 8.0 g (0.02 mol) of ferric sulfate dissolved in 200 ml of ion-exchanged water were kept at 20 ° C. while stirring the mixed solution thus obtained. The oxidation catalyst solution was added and stirred for 3 hours to react.
The obtained reaction solution was dialyzed to remove unreacted monomers and oxidants to obtain a solution containing about 1.5% by mass of polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene). Then, 2.79 g of imidazole was dissolved in 100 ml of this solution to obtain a conductive polymer solution having a pH of 8.1. The pH was measured at 25 ° C. (the same applies to the following examples).
In order to evaluate the performance of the π-conjugated conductive polymer, the obtained conductive polymer solution was applied onto glass and dried in a 120 ° C. hot air dryer to form a 2 μm thick conductive film. The electrical conductivity was measured with Loresta (manufactured by Dia Instruments). The results are shown in Table 1.

(2) Manufacture of capacitors After connecting the anode lead terminal to the etched aluminum foil (anode stay), it is formed (oxidized) in an aqueous solution of 10% by weight ammonium adipate to form a dielectric layer on the surface of the aluminum foil. Thus, a capacitor intermediate was obtained.
Next, a counter aluminum cathode foil with a cathode lead terminal welded to the anode foil of the capacitor intermediate was laminated through a cellulose separator, and this was wound up to obtain a capacitor element.
After immersing this capacitor element in the conductive polymer solution prepared in (1) under reduced pressure, the process of drying for 10 minutes with a hot air dryer at 150 ° C. is repeated 5 times on the dielectric layer side surface of the capacitor intermediate. A solid electrolyte layer was formed.
Next, the capacitor was fabricated by sealing the aluminum case with a capacitor element on which a solid electrolyte layer was formed and a sealing rubber.
Using the LCZ meter 2345 (manufactured by NF Circuit Design Block Co., Ltd.), measured the capacitance at 120 Hz, the initial value of the equivalent series resistance (ESR) at 100 kHz, and the ESR after 1000 hours at 150 ° C. did.

(Example 2)
In Example 1, instead of adding 2.79 g of imidazole to a solution containing about 1.5% by weight of polystyrene sulfonate-doped poly (3,4-ethylenedioxythiophene), 2.38 g of hydroxyethyl acrylate was added. A conductive polymer solution having a pH of 5.4 was obtained. Then, a capacitor was produced in the same manner as in Example 1.
The produced capacitor was measured for capacitance at 120 Hz, initial value of ESR at 100 kHz, and ESR after 1000 hours at 150 ° C. The measurement results are shown in Table 1.

(Example 3)
In Example 1, instead of adding 2.79 g of imidazole to a solution containing about 1.5% by weight of polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene), 2.52 g of diethylamine was added, and 100 ° C. For 12 hours to obtain a conductive polymer solution having a pH of 12.4. Then, a capacitor was produced in the same manner as in Example 1.
The produced capacitor was measured for capacitance at 120 Hz, initial value of ESR at 100 kHz, and ESR after 1000 hours at 150 ° C. The measurement results are shown in Table 1.

(Comparative Example 1)
A capacitor was produced in the same manner as in Example 1 except that imidazole was not added in the preparation of the conductive polymer solution of Example 1. In this case, the pH of the conductive polymer solution was 1.2.
For the produced capacitor, the electrostatic capacity at 120 Hz, the electrical conductivity of the conductive film, the initial value of ESR at 100 kHz, and the ESR after 1000 hours at 150 ° C. were measured. The measurement results are shown in Table 1.

Example 4
After adding 10 g of N-methyl-2-pyrrolidone to the solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1, the aqueous solution was added with ammonia water to have a pH of 7.5. A polymer solution was obtained.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 5)
After adding 10 g of dimethyl sulfoxide to the solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1, aqueous ammonia was added to obtain a conductive polymer solution having a pH of 7.5. It was.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 6)
10 g of N-vinylacetamide was added to the solution containing polystyrene sulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1 and then aqueous ammonia was added to form a conductive polymer solution having a pH of 7.5. Got.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 7)
After adding 6 g of ethylene glycol to the solution containing polystyrene sulfonate-doped poly (3,4-ethylenedioxythiophene) in Example 1, an aqueous ammonia is added to obtain a conductive polymer solution having a pH of 7.5. It was.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 8)
After adding 6 g of glycerin to the solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1, an aqueous ammonia was added to obtain a conductive polymer solution having a pH of 7.5. .
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

Example 9
After adding 10 g of cresol to the solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1, an aqueous ammonia was added to obtain a conductive polymer solution having a pH of 7.5. .
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 10)
In Example 5, instead of adding aqueous ammonia, imidazole was added to obtain a conductive polymer solution having a pH of 7.5.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 11)
In Example 5, instead of adding aqueous ammonia, diethylamine was added to obtain a conductive polymer solution having a pH of 7.5.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 12)
Aqueous ammonia was added to the solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) in Example 1 to obtain a solution having a pH of 7.4. To this solution was added 10 g of N, N-dimethylacetamide (DMAc) to obtain a conductive polymer solution having a pH of 6.9.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Example 13)
In Example 12, 4 g of 20% aqueous ammonia and N, N-dimethylacetamide were mixed to obtain a mixed solution. This mixed solution was added to a solution containing polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) to obtain a conductive polymer solution having a pH of 6.3.
The electrical conductivity of the obtained conductive polymer solution was measured in the same manner as in Example 1, and a capacitor was produced using the obtained conductive polymer solution and evaluated in the same manner as in Example 1. . The results are shown in Table 1.

(Comparative Examples 2-7)
Capacitors of Comparative Examples 2 to 7 were obtained in the same manner as Examples 4 to 9, respectively, except that ammonia water was not added when preparing the conductive polymer solutions of Examples 4 to 9. These capacitors were evaluated in the same manner as in Example 1.

In the capacitors of Examples 1 to 13 having a solid electrolyte layer formed from a conductive polymer solution having a pH adjusted to 3 to 13 as a cathode, corrosion of the dielectric layer is prevented, and the solid electrolyte The ESR was low because of the high electrical conductivity. Particularly, the ESR after 1000 hours at 150 ° C. was low. The capacitance was also high.
In contrast, the capacitors of Comparative Examples 1 to 7 having a solid electrolyte layer formed from a conductive polymer solution whose pH is not adjusted to 3 to 13 as a cathode cannot prevent corrosion of the dielectric layer. , ESR could not be lowered. In the capacitors of Comparative Examples 2 to 7, since the conductive polymer solution containing the organic solvent was used when forming the solid electrolyte layer, the electrical conductivity was high, but the corrosion of the dielectric layer could not be prevented. , ESR could not be increased.

It is sectional drawing which shows one example of embodiment in the capacitor | condenser of this invention.

Explanation of symbols

10 Capacitor 11 Anode 12 Dielectric Layer 13 Cathode 13a Solid Electrolyte Layer

Claims (5)

In a capacitor having an anode made of a porous body of a valve metal, a dielectric layer formed by oxidizing the surface of the anode, and a cathode formed on the dielectric layer and provided with a solid electrolyte layer,
The cathode solid electrolyte layer is formed by applying a conductive polymer solution containing a π-conjugated conductive polymer, a polyanion, and a solvent and having a pH adjusted to 3 to 13 at 25 ° C. Capacitor characterized by.   2. The capacitor according to claim 1, wherein an alkali is added to the conductive polymer solution and the pH is adjusted to the above range.   The capacitor according to claim 2, wherein the alkali is a nitrogen-containing aromatic cyclic compound.   The capacitor according to claim 1, wherein the conductive polymer solution contains a compound having at least one of a hydroxyl group, a glycidyl group, and an amino group in the molecule.  A π-conjugated conductive polymer, a polyanion, and a solvent are formed on the dielectric layer side surface of the capacitor intermediate having an anode made of a valve metal porous body and a dielectric layer formed by oxidizing the surface of the anode. And a step of applying a conductive polymer solution having a pH adjusted to 3 to 13 at 25 ° C. and drying the solution.

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