JP2014007401A - Conductive polymer dispersion for producing solid electrolytic capacitor, and solid electrolytic capacitor produced using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a conductive polymer dispersion for producing a solid electrolytic capacitor which can produce a solid electrolytic capacitor having excellent ESR and excellent charge-discharge behavior; and a solid electrolytic capacitor produced using the same.SOLUTION: A conductive polymer dispersion for producing a solid electrolytic capacitor is provided which at least contains a compound represented by the general formula (1), a conductive polymer, and a dispersion medium. Also provided is a solid electrolytic capacitor produced using the conductive polymer dispersion.

Description

  The present invention relates to a conductive polymer dispersion for producing a solid electrolytic capacitor and a solid electrolytic capacitor produced using the same.

  Conductive polymers such as polyaniline, polypyrrole and polythiophene have excellent stability and conductivity, so various antistatic agents, electrolytes for solid electrolytic capacitors, anticorrosion paints, EMI shields, chemical sensors, display elements, nonlinear materials Application to plating primer is expected.

  These conductive polymer substances generally have a problem that they are insoluble or hardly soluble in a solvent and are infusible, so that molding and processing are difficult.

  For this reason, a technique for improving the moldability and workability by partially pulverizing the conductive polymer into fine particles or fillers and dispersing it in a dispersion medium such as water or an organic solvent is known.

  A solid electrolytic capacitor generally has a configuration in which a solid electrolyte layer containing a conductive polymer is formed on a valve action metal having a dielectric oxide film.

  As a method for producing a solid electrolyte layer containing a conductive polymer, there are a chemical oxidative polymerization method and an electrolytic polymerization method. As disclosed in No. 1, polyaniline is prepared by chemical oxidative polymerization of aniline while coexisting a dopant component having a sulfo group, a carboxyl group, etc., and the polyaniline aqueous solution is applied and dried to form a coating film. There is a way. In this method, a solid electrolyte layer containing a conductive polymer having high conductivity can be easily formed.

Patent Document 2 describes a capacitor containing a π-conjugated conductive polymer, a polyanion, and an ion conductive compound in a solid electrolyte layer, and a nitrogen-containing aromatic cyclic compound, 2 Compound having one or more hydroxyl groups, Compound having two or more carboxyl groups, Compound having one or more hydroxyl groups and one or more carboxyl groups, Compound having an amide group, Compound having an imide group, Lactam compound It is described that one or more conductivity improvers selected from the group consisting of compounds having a glycidyl group may be contained.
However, a solid electrolytic capacitor manufactured using a solution in which a conductivity improver described in Examples is actually contained in a conductive polymer solution is equivalent series resistance (hereinafter abbreviated as “ESR”). In addition, there is a problem inferior charge / discharge characteristics.

  In view of the above, there has been a demand for a conductive polymer dispersion capable of producing a solid electrolytic capacitor having excellent ESR and charge / discharge characteristics, and a solid electrolytic capacitor produced using the same.

Japanese Patent Laid-Open No. 07-106718 JP 2008-109065 A

  An object of the present invention is to provide a conductive polymer dispersion for producing a solid electrolytic capacitor capable of producing a solid electrolytic capacitor having excellent ESR and excellent charge / discharge characteristics, and a solid electrolytic capacitor produced using the same. It is.

  The present inventors include at least a compound represented by the general formula (1), a conductive polymer, and a dispersion medium, and a conductive polymer dispersion for producing a solid electrolytic capacitor, and the same The present inventors have found that a solid electrolytic capacitor produced using the above can solve the above-mentioned problems and have completed the present invention.

  That is, the present invention is as follows.

  A first invention is a conductive polymer dispersion for producing a solid electrolytic capacitor, comprising at least a compound represented by the following general formula (1), a conductive polymer, and a dispersion medium. is there.

（式（１）中、Ｒ_１は、水素原子、炭素数１〜１０のアルキル基、炭素数１〜６のヒドロキシアルキル基のいずれかを示し、Ｒ_２は、炭素数０〜６の炭化水素基又はアミノ基を示す。なお、炭素数０とは、ＣとＣＯＯＨが直接結合しているものをいう。）

(In the formula (1), R ₁ represents any of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents a hydrocarbon having 0 to 6 carbon atoms. Represents a group or an amino group, where the number of carbon atoms of 0 means that C and COOH are directly bonded.)

  The second invention is a conductive polymer for producing a solid electrolytic capacitor according to the first invention, wherein the compound represented by the general formula (1) is the following compound (A) or (B): It is a dispersion.

  The third invention is characterized in that the content of the compound represented by the general formula (1) in the conductive polymer dispersion for producing a solid electrolytic capacitor is 0.01 to 20% by mass. A conductive polymer dispersion for producing a solid electrolytic capacitor according to the second invention.

  A fourth invention is the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to third inventions, wherein the conductive polymer is a polythiophene.

  A fifth invention is the conductive polymer dispersion for producing a solid electrolytic capacitor according to the fourth invention, wherein the dopant component constituting the polythiophene is polystyrene sulfonic acid.

  6th invention contains at least 1 sort (s) chosen from the group which consists of ethylene glycol, (gamma) -butyrolactone, and polyethyleneglycol, The solid electrolytic capacitor as described in any one of 1st to 5th invention characterized by the above-mentioned. This is a conductive polymer dispersion for production.

  A seventh invention is the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to sixth inventions, which contains an alkaline compound.

  An eighth invention is the conductive polymer dispersion for producing a solid electrolytic capacitor according to the seventh invention, wherein the alkaline compound is a tertiary amine.

  The ninth invention is a method in which a valve metal having a dielectric oxide film is immersed in the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to eighth inventions, or pulled up, or Then, after applying the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to eighth inventions to a valve metal having a dielectric oxide film, the dielectric film is dried. It has the process of forming the solid electrolyte layer containing a conductive polymer on the valve action metal which has this, It is a manufacturing method of the solid electrolytic capacitor characterized by the above-mentioned.

According to a tenth aspect of the present invention, there is provided a method for producing a solid electrolytic capacitor including a step of forming a conductive polymer layer on a valve metal having a dielectric oxide film formed thereon.
The step of forming the conductive polymer layer includes
A step of bringing the polyaniline solution into contact with the valve action metal on which the dielectric oxide film is formed, followed by heating and drying to form a polyaniline layer on the valve action metal;
After the valve action metal having a polyaniline layer is dipped in the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to eighth inventions, or has a dielectric oxide film The valve action metal is coated with the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of the first to eighth inventions, dried, and then conductive on the valve action metal having a polyaniline layer. Forming a solid electrolyte layer containing a polymer;
It is a manufacturing method of the solid electrolytic capacitor characterized by having.

The eleventh invention is a solid electrolytic capacitor having a solid electrolyte layer containing a conductive polymer on a valve action metal having a dielectric oxide film.
The solid electrolyte layer containing a conductive polymer contains at least a conductive polymer and a compound represented by the following general formula (1).

（式（１）中、Ｒ_１は、水素原子、炭素数１〜１０のアルキル基、炭素数１〜６のヒドロキシアルキル基のいずれかを示し、Ｒ_２は、炭素数０〜６の炭化水素基又はアミノ基を示す。なお、炭素数０とは、ＣとＣＯＯＨが直接結合しているものをいう。）

(In the formula (1), R ₁ represents any _one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents a hydrocarbon having 0 to 6 carbon atoms. Represents a group or an amino group, where the number of carbon atoms of 0 means that C and COOH are directly bonded.)

  A twelfth invention is the solid electrolytic capacitor according to the eleventh invention, wherein the compound represented by the general formula (1) is the following compound (A) or (B).

  According to the present invention, it is possible to provide a conductive polymer dispersion for producing a solid electrolytic capacitor capable of producing a solid electrolytic capacitor having excellent ESR and charge / discharge characteristics, and a solid electrolytic capacitor produced using the same. it can.

  The conductive polymer dispersion for producing a solid electrolytic capacitor of the present invention will be described.

  The conductive polymer dispersion of the present invention contains at least a compound represented by the following general formula (1), a conductive polymer, and a dispersion medium. It is a polymer dispersion.

In the general formula (1), R ₁ represents any _one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents carbonization having 0 to 6 carbon atoms. A hydrogen group or an amino group is shown. In addition, C 0 means that C and COOH are directly bonded.

  Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

  Examples of the hydroxyalkyl group having 1 to 6 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, and a hydroxyhexyl group.

  Examples of the hydrocarbon group having 0 to 6 carbon atoms include methylene group, ethylene group, propylene group, butylene group, isopropylene group, isobutylene group, t-butylene group, pentylene group, hexylene group and other alkylene groups, vinylene group, Examples include an alkenylene group such as an arylene group, a butenylene group, a pentenylene group, and a hexenylene group. In addition, C 0 represents that C and COOH are directly bonded.

Specific examples of the compound represented by the general formula (1) include the following compounds (A) to (L).

  Among the above-mentioned compounds (A) to (L), compounds (A) to (D) are more preferable from the viewpoint of excellent ESR and charge / discharge characteristics of the obtained solid electrolytic capacitor, and compound (A) or (B) Is particularly preferred.

  The content of the compound represented by the general formula (1) in the conductive polymer dispersion is preferably 0.01 to 20% by mass, more preferably 0.05 to 15% by mass, and Particularly preferred is 1 to 10% by mass. By setting it within this range, a solid electrolytic capacitor having particularly excellent ESR and charge / discharge characteristics can be produced.

  By containing the compound represented by the general formula (1) in the conductive polymer dispersion for producing a solid electrolytic capacitor, the compound interacts with the conductive polymer or the dopant of the conductive polymer, so that The characteristic is improved.

  The conductive polymer used in the present invention is a polymer doped with a dopant component. The monomer compound used for the conductive polymer is not particularly limited, and for example, pyrroles, thiophenes, anilines, and the like can be used. Among these, thiophenes are preferably mentioned from the viewpoint that a conductive polymer excellent in conductivity and dispersion stability can be obtained, and because the transparency of the conductive film formed by this dispersion is excellent, A conductive polymer of the compound represented by the general formula (2) is preferably mentioned.

In the general formula (2), X represents an oxygen atom or a sulfur atom. Y represents the same or different oxygen atom or sulfur atom. R ₃ represents a linear or branched alkylene group having 1 to 6 carbon atoms.

  Specific examples of the compound represented by the general formula (2) include 3,4-ethylenedioxythiophene, methyl-3,4-ethylenedioxythiophene, ethyl-3,4-ethylenedioxythiophene, and propyl. -3,4-ethylenedioxythiophene, 3,4-propylenedioxythiophene, methyl-3,4-propylenedioxythiophene, ethyl-3,4-propylenedioxythiophene, propyl-3,4-propylenedioxy Thiophene, 3,4-ethylenedioxyfuran, methyl-3,4-ethylenedioxyfuran, ethyl-3,4-ethylenedioxyfuran, propyl-3,4-ethylenedioxyfuran, 3,4-propylenedi Oxyfuran, methyl-3,4-propylenedioxyfuran, ethyl-3,4-propylenedioxyph , Propyl-3,4-propylenedioxyfuran, 3,4-ethylenedithiathiophene, methyl-3,4-ethylenedithiathiophene, ethyl-3,4-ethylenedithiathiophene, propyl-3,4- Examples include ethylenedithiathiophene, 3,4-propylenedithiathiophene, methyl-3,4-propylenedithiathiophene, ethyl-3,4-propylenedithiathiophene, and propyl-3,4-propylenedithiathiophene. .

  Among these, it is possible to obtain a conductive polymer dispersion for producing a solid electrolytic capacitor having better dispersibility, and the solid electrolytic capacitor produced using the conductive polymer dispersion for producing a solid electrolytic capacitor has an electrical property. From the viewpoint of superiority, 3,4-ethylenedioxythiophene, methyl-3,4-ethylenedioxythiophene, and ethyl-3,4-ethylenedioxythiophene are particularly preferred.

  The conductive polymer used in the present invention can be obtained by subjecting the compound represented by the general formula (2) to chemical oxidative polymerization or electrolytic oxidative polymerization in the presence of the dopant component.

  The dopant component only needs to have a functional group capable of causing chemical oxidation doping to the polymer, and preferred examples include a sulfate ester group, a phosphate ester group, a phosphate group, a carboxyl group, and a sulfo group. Among these, from the point of the dope effect, a sulfate group, a carboxyl group, and a sulfo group are more preferable, and a sulfo group is particularly preferable.

Specific examples of the dopant component 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- (Acrylamido-2-methylsulfonic acid), polyisoprenesulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl sulfonic acid, polymethacryl carboxylic acid, poly (2-acrylamido-2-methyl carboxylic acid), Examples thereof include polyisoprene carboxylic acid, paratoluene sulfonic acid, xylene sulfonic acid, methyl naphthalene sulfonic acid, butyl naphthalene sulfonic acid, and metal salts thereof. These may be a single polymer or two or more types of copolymers.
Among these, polystyrene sulfonic acid is particularly preferable.

  The conductive polymer is particularly preferably polystyrene sulfonate-doped poly (3,4-ethylenedioxythiophene), polystyrene sulfonate-doped poly (methyl-3,4-ethylenedioxythiophene), or polystyrene sulfonate dope. Of poly (ethyl-3,4-ethylenedioxythiophene).

  1: 1-6 are preferable and, as for mass ratio of the monomer compound and dopant component used when manufacturing a conductive polymer, 1: 2-5 are mentioned especially preferable. By setting it as this mass ratio, the conductive polymer which has the more excellent electroconductivity and dispersibility can be obtained, As a result, the obtained solid electrolytic capacitor becomes the thing excellent in ESR. When the mass ratio of the monomer compound 1 and the dopant exceeds 1: 6, there is a problem that the ESR of the obtained solid electrolytic capacitor is increased.

  As the dispersion medium, water or an organic solvent can be used.

  As the organic solvent, alcohols, ketones, esters, ethers, cellosolves, aromatic hydrocarbons, aliphatic hydrocarbons and the like can be used.

  Examples of alcohols include methanol, ethanol, 1-propanol, isopropyl alcohol, n-butanol, s-butanol, t-butanol, n-amyl alcohol, s-amyl alcohol, t-amyl alcohol, allyl alcohol, isoamyl alcohol, and isobutyl. Alcohol, 2-ethylbutanol, 2-octanol, n-octanol, cyclohexanol, tetrahydrofurfuryl alcohol, furfuryl alcohol, n-hexanol, n-heptanol, 2-heptanol, 3-heptanol, benzyl alcohol, methylcyclohexanol, Examples include ethylene glycol, ethylene glycol monomethyl ether, glycerin, diethylene glycol, and propylene glycol.

  Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, methyl isobutyl ketone, and methyl-n-propyl ketone.

  Esters include ethyl acetoacetate, ethyl benzoate, methyl benzoate, isobutyl formate, ethyl formate, propyl formate, methyl formate, isobutyl acetate, ethyl acetate, propyl acetate, methyl acetate, methyl salicylate, diethyl oxalate, diethyl tartrate , Dibutyl tartrate, ethyl phthalate, methyl phthalate, butyl phthalate, γ-butyrolactone, ethyl malonate, methyl malonate and the like.

  Examples of cellosolves include methyl cellosolve and ethyl cellosolve.

  Aromatic hydrocarbons include benzene, toluene, xylene and the like.

  Examples of aliphatic hydrocarbons include hexane and cyclohexane.

  Among the dispersion media, water is particularly preferable.

The conductive polymer dispersion for producing a solid electrolytic capacitor of the present invention may contain a high boiling point organic solvent. Among the high boiling point organic solvents, a high boiling point organic solvent having a boiling point of 150 to 300 ° C. is particularly preferable. Specific examples of the high-boiling organic solvent include N-methyl-2-pyrrolidone (boiling point 202 ° C.), dimethyl sulfoxide (boiling point 189 ° C.), γ-butyrolactone (boiling point 204 ° C.), sulfolane (boiling point 285 ° C.), dimethyl sulfone. (Boiling point 233 ° C.), ethylene glycol (boiling point 198 ° C.), diethylene glycol (boiling point 244 ° C.), polyethylene glycol (molecular weight 200 to 600) (boiling point 250 ° C.) and the like.
Among these, at least one selected from the group consisting of ethylene glycol, γ-butyrolactone, and polyethylene glycol is preferred because it can form a solid electrolyte layer containing a conductive polymer having a uniform surface. In particular, a combination of ethylene glycol and polyethylene glycol can produce a solid electrolytic capacitor having excellent charge / discharge characteristics.

  The content of the organic solvent in the conductive polymer dispersion for producing a solid electrolytic capacitor is preferably 1 to 20% by mass, particularly preferably 5 to 15% by mass. When the amount is less than 1% by mass, there is a problem that the effect of forming a solid electrolyte layer containing a conductive polymer having a uniform surface is slightly inferior. When the amount exceeds 20% by mass, there is a problem that the drying process takes time.

The conductive polymer dispersion for producing a solid electrolytic capacitor may contain a binder resin, a surfactant, and an alkali compound in order to adjust the film formability and film strength.
The binder resin is preferably a thermosetting resin or a thermoplastic resin. Specifically, polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyimides such as polyimide and polyamideimide, fluororesins such as polyvinylidene fluoride, polyvinyl fluoride and polytetrafluoroethylene, polyvinyl alcohol, polyvinyl ether, Examples thereof include vinyl resins such as polyvinyl butyral, polyvinyl acetate, and polyvinyl chloride, epoxy resins, xylene resins, polyurethane, phenolic resins, polyethers, acrylic resins, and copolymers thereof.

  In order to improve the impregnation property for the capacitor, an alkaline compound may be contained. By improving the impregnation property of the capacitor, a solid electrolytic capacitor having an excellent capacitance can be produced.

The alkaline compound may be any compound that exhibits alkalinity, and includes known inorganic alkaline compounds and organic alkaline compounds.
As an inorganic alkaline compound, sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia etc. are mentioned, for example.
Examples of the organic alkaline compound include aromatic amines, aliphatic amines, and metal alkoxides. Examples of the aromatic amine include imidazole and pyrazole. Examples of the metal alkoxide include sodium methoxide, sodium butoxide, sodium ethoxide, potassium butoxide and the like. Aliphatic amines include primary amines, secondary amines, and tertiary amines, such as dimethylamine, diethylamine, dipropylamine, dibutylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, methanol. Examples include amine, dimethanolamine, trimethanolamine, ethanolamine, diethanolamine, triethanolamine, and polyallylamine. Of the aliphatic amines, tertiary amines are preferred because they are easily impregnated in the capacitor. Among tertiary amines, trimethylamine or triethylamine is preferred, and triethylamine is particularly preferred.

  Examples of the surfactant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. Examples of the cationic surfactant include tertiary amine salt, quaternary ammonium salt and the like. Examples of amphoteric surfactants include carboxybetaine, aminocarboxylate, and imidazolium betaine. Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene glycerin fatty acid ester, and ethylene. Examples include glycol fatty acid esters and polyoxyethylene fatty acid amides.

  Note that the conductive polymer dispersion for producing a solid electrolytic capacitor of the present invention is one in which a conductive polymer is dispersed in a dispersion medium, and a part of the conductive polymer is dissolved in the dispersion medium. Good.

<Method for manufacturing solid electrolytic capacitor>
A method for manufacturing the solid electrolytic capacitor will be described in detail below.

  The conductive polymer dispersion for producing a solid electrolytic capacitor described above is contacted with a valve action metal having a dielectric oxide film, and then dried, so that the conductive polymer is deposited on the valve action metal having the dielectric oxide film. The solid electrolyte layer containing can be formed by any method, but preferably a dipping method or a coating method.

  Specifically, after the valve action metal having a dielectric oxide film is dipped in the conductive polymer dispersion for producing the solid electrolytic capacitor described above and pulled up, or the valve action metal having the dielectric oxide film is applied to the solid electrolyte described above. It is preferable to have a step of forming a solid electrolyte layer containing a conductive polymer on a valve action metal having a dielectric oxide film after being coated with a conductive polymer dispersion for capacitor production.

  Further, in the method of manufacturing a solid electrolytic capacitor having a step of forming a conductive polymer layer on the valve action metal on which the dielectric oxide film is formed, the step of forming the conductive polymer layer includes a polyaniline solution as a dielectric. A process for forming a polyaniline layer on the valve action metal after contacting with the valve action metal on which the oxide film is formed, and a valve action metal having the polyaniline layer for producing the above-described solid electrolytic capacitor After dipping in a conductive polymer dispersion and pulling it up, or after applying the above-mentioned conductive polymer dispersion for producing a solid electrolytic capacitor to a valve metal having a dielectric oxide film, drying, the polyaniline layer And a step of forming a solid electrolyte layer containing a conductive polymer on the valve action metal having, more preferably a method for producing a solid electrolytic capacitor, characterized in that It is below.

  The polyaniline solution contains polyaniline and an organic solvent. The polyaniline may be a polymer containing only aniline, or may be a copolymer of aniline and an aniline derivative having a substituent. Examples of the organic solvent used in the polyaniline solution include pyrrolidones such as N-methylpyrrolidone, amides such as dimethylformamide and propionamide, polar solvents such as dimethylimidazolidinone, dimethylpyrimidinone, cresol and dimethylpropylene urea. It is done. Among these, N-methylpyrrolidone, N, N-dimethylpropylene urea, γ-butyrolactone, dimethylformamide, or a mixed solvent thereof is particularly preferable because of its excellent solubility in polyaniline.

  By forming the polyaniline layer on the valve action metal having the dielectric oxide film, the capacitance of the obtained solid electrolytic capacitor can be improved.

  Examples of the valve metal used in the present invention include one selected from the group consisting of aluminum, tantalum, niobium, and titanium, and are used in the form of a sintered body or foil.

  Depending on the type and shape of the valve metal used, it can be either a tip type or a wound type.

  The process of immersing the valve action metal having a dielectric oxide film in the conductive polymer dispersion for producing a solid electrolytic capacitor, pulling it up, and drying it may be repeated a plurality of times. The preferred number of times is preferably 1 to 6 times, particularly preferably 2 to 5 times.

  Moreover, after applying the valve action metal having a dielectric oxide film to the conductive polymer dispersion for producing a solid electrolytic capacitor, the drying step may be repeated a plurality of times. The preferred number of times is preferably 1 to 6 times, particularly preferably 2 to 5 times.

  Drying may be any of natural drying at room temperature to heat drying. However, when a high-boiling organic solvent is contained in the conductive polymer dispersion for producing a solid electrolytic capacitor, drying is performed by heating to 150 ° C or higher. Preferably it is made to do.

<Solid electrolytic capacitor>
The solid electrolytic capacitor of the present invention may be produced by the method described above, or may be produced by a method other than the above method.
The solid electrolytic capacitor of the present invention is a solid electrolytic capacitor having a solid electrolyte layer containing a conductive polymer on a valve action metal having a dielectric oxide film, wherein the solid electrolyte layer containing the conductive polymer is electrically conductive. Containing at least a functional polymer and a compound represented by the following general formula (1).

In the general formula (1), R ₁ represents any of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents carbonization having 0 to 6 carbon atoms. A hydrogen group or an amino group is shown. In addition, C 0 means that C and COOH are directly bonded.
The detailed description of the compound represented by the general formula (1) and the conductive polymer is the same as described above.

  Among the compounds represented by the general formula (1), the following compound (A) or (B) is particularly preferable.

  The mass ratio of the content of the conductive polymer and the compound represented by the general formula (1) is preferably 1: 0.1 to 1:10, and more preferably 1: 0.5 to 1: 5. Preferably mentioned.

  Examples of the valve metal include one selected from the group consisting of aluminum, tantalum, niobium, and titanium, and are used in the form of a sintered body or foil.

  Depending on the type and shape of the valve metal used, it can be either a tip type or a wound type.

  The solid electrolytic capacitor of the present invention contains a compound represented by the above general formula (1) in a solid electrolyte layer containing a conductive polymer, thereby interacting with the conductive polymer and having excellent ESR and Charge / discharge characteristics can be obtained.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited at all by this Example. In the examples, “part” represents “part by mass”, and “%” represents “% by mass”.

Example 1
(Manufacture of conductive polymer dispersion for manufacturing solid electrolytic capacitors)
14.2 parts of 3,4-ethylenedioxythiophene and a solution of 42.6 parts of polystyrene sulfonic acid (mass average molecular weight: 75,000) dissolved in 2000 ml of ion-exchanged water were mixed at 20 ° C. A mixed solution was obtained.
While maintaining the obtained mixed solution at 20 ° C., 29.6 parts of ammonium persulfate dissolved in 200 ml of ion-exchange water and 8.0 parts of an oxidation catalyst solution of ferric sulfate were added while stirring. The reaction was stirred for an hour.

  After the reaction, a strongly acidic cation exchange resin (manufactured by Mitsubishi Plastics, PK-216) was added to remove the ammonium salt, and then the ion exchange resin was removed. Next, a strong basic anion exchange resin (manufactured by Mitsubishi Plastics, PA-418) was added to remove the sulfate, and then the ion exchange resin was removed to obtain 1.5% polyethylenedioxythiophene / polystyrenesulfonic acid. An aqueous dispersion was obtained.

  100 parts of a 1.5% polyethylenedioxythiophene / polystyrene sulfonic acid aqueous dispersion is mixed with 3 parts of 2,2-bis (hydroxymethyl) propionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 10 parts of ethylene glycol to produce solid electrolyte. A conductive polymer dispersion for capacitor production was obtained.

(Manufacture of solid electrolytic capacitors)
As a valve metal used for the anode, an etched aluminum foil (length: 8.0 mm × width: 50.0 mm) whose surface was etched and roughened was used, and the aluminum foil was subjected to voltage in an aqueous solution of ammonium adipate. A lead terminal is attached to an anode formed with a dielectric layer by performing a chemical conversion treatment at 90 V, a lead terminal is attached to a cathode made of aluminum foil, and the anode with the lead terminal and the cathode are opposed to each other through a separator. Thus, a capacitor element was produced.

  Next, the process of immersing the capacitor element in the conductive polymer solution for producing a solid electrolytic capacitor obtained above for 5 minutes and drying at 150 ° C. for 5 minutes is repeated three times to obtain a solid containing the conductive polymer. A capacitor element having an electrolyte layer was produced.

  Next, a carbon paste and a silver paste were applied to the capacitor element and then dried to form a cathode lead layer. Next, the cathode was bonded by silver paste or the like, the anode was joined by welding, the capacitor element was fixed on the lead frame, and transfer molding was performed with an epoxy resin to produce a solid electrolytic capacitor.

(Example 2)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with 2,2-bis (hydroxymethyl) butyric acid.

(Example 3)
A solid was obtained in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with N- [tris (hydroxymethyl) methyl] glycine (manufactured by Tokyo Chemical Industry Co., Ltd.). An electrolytic capacitor was produced.

Example 4
The same as Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with 3-hydroxy-2,2-bis (hydroxymethyl) propanoic acid (manufactured by Aldrich). Thus, a solid electrolytic capacitor was produced.

(Example 5)
A solid electrolytic capacitor in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with 4-hydroxy-3- (hydroxymethyl) -3-methylbutanoic acid. Was made.

(Example 6)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 1.

(Example 7)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 1 part of triethylamine was contained in the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 2.

(Example 8)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 3.

(Comparative Example 1)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was not used.

(Comparative Example 2)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with pentaerythritol.

(Comparative Example 3)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with pentaglycerol.

(Comparative Example 4)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with tris (hydroxymethyl) aminomethane (manufactured by Tokyo Chemical Industry Co., Ltd.). did.

(Comparative Example 5)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 1 was replaced with 2-hydroxymethylbenzoic acid.

<Evaluation of ESR and charge / discharge characteristics of solid electrolytic capacitor>
For the solid electrolytic capacitors obtained from Examples 1 to 8 and Comparative Examples 1 to 5, the equivalent series resistance (ESR) at 100 kHz was measured, and the ESR after a high temperature load test (maintained in an atmosphere at a temperature of 120 ° C. for 100 hours) Was measured.

Moreover, the charge / discharge characteristic was measured about the solid electrolytic capacitor obtained from Examples 1-8 and Comparative Examples 1-5. The charge / discharge characteristics of the solid electrolytic capacitor were evaluated by measuring the initial capacitance and the capacitance after 10,000 cycles according to the conditions of the following charge / discharge characteristics test to determine the rate of change. Table 1 shows the measurement results of ESR and charge / discharge characteristics.
Conditions for charge / discharge characteristics test Applied voltage: 50V
Charging / discharging resistance: 1 kΩ
Temperature: 105 ° C
Charging / discharging cycle: 30 seconds charging, 30 seconds discharging as one cycle

Abbreviations in the table are as follows.
Compound (A): 2,2-bis (hydroxymethyl) propionic acid compound (B): 2,2-bis (hydroxymethyl) butyric acid compound (C): N- [tris (hydroxymethyl) methyl] glycine compound (D ): 3-hydroxy-2,2-bis (hydroxymethyl) propanoic acid compound (E): 4-hydroxy-3- (hydroxymethyl) -3-methylbutanoic acid compound I: pentaerythritol compound II: pentaglycerol compound III: Tris (hydroxymethyl) aminomethane compound IV: 2-hydroxymethylbenzoic acid

  From Table 1, it can be seen that Examples 1 to 8 are superior to Comparative Examples 1 to 5 in ESR and charge / discharge characteristics in the solid electrolytic capacitor. In particular, it can be seen that a solid electrolytic capacitor produced using a conductive polymer dispersion for producing a solid electrolytic capacitor containing triethylamine is more excellent in ESR and charge / discharge characteristics.

Example 9
(Manufacture of conductive polymer dispersion for manufacturing solid electrolytic capacitors)
14.2 parts of 3,4-ethylenedioxythiophene and a solution of 42.6 parts of polystyrene sulfonic acid (mass average molecular weight: 75,000) dissolved in 2000 ml of ion-exchanged water were mixed at 20 ° C. A mixed solution was obtained.
While maintaining the obtained mixed solution at 20 ° C., 29.6 parts of ammonium persulfate dissolved in 200 ml of ion-exchange water and 8.0 parts of an oxidation catalyst solution of ferric sulfate were added while stirring. The reaction was stirred for an hour.

  After the reaction, a strongly acidic cation exchange resin (manufactured by Mitsubishi Plastics, PK-216) was added to remove the ammonium salt, and then the ion exchange resin was removed. Next, a strong basic anion exchange resin (manufactured by Mitsubishi Plastics, PA-418) was added to remove the sulfate, and then the ion exchange resin was removed to obtain 1.5% polyethylenedioxythiophene / polystyrenesulfonic acid. An aqueous dispersion was obtained.

  100 parts of a 1.5% polyethylenedioxythiophene / polystyrene sulfonic acid aqueous dispersion is mixed with 3 parts of 2,2-bis (hydroxymethyl) propionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 10 parts of ethylene glycol to produce solid electrolyte. A conductive polymer dispersion for capacitor production was obtained.

(Manufacture of solid electrolytic capacitors)
As a valve metal used for the anode, an etched aluminum foil (length: 8.0 mm × width: 50.0 mm) whose surface was etched and roughened was used, and the aluminum foil was subjected to voltage in an aqueous solution of ammonium adipate. A lead terminal is attached to an anode formed with a dielectric layer by performing a chemical conversion treatment at 90 V, a lead terminal is attached to a cathode made of aluminum foil, and the anode with the lead terminal and the cathode are opposed to each other through a separator. Thus, a capacitor element was produced.

  Next, after immersing the capacitor element in a 2% polyaniline solution (solvent: N-methylpyrrolidone) for 5 minutes and drying at 150 ° C. for 5 minutes, the obtained conductive polymer solution for producing a solid electrolytic capacitor was used. The above capacitor element was immersed for 5 minutes and dried at 150 ° C. for 5 minutes three times to produce a capacitor element having a solid electrolyte layer containing a conductive polymer.

  Next, a carbon paste and a silver paste were applied to the capacitor element and then dried to form a cathode lead layer. Next, the cathode was bonded by silver paste or the like, the anode was joined by welding, the capacitor element was fixed on the lead frame, and transfer molding was performed with an epoxy resin to produce a solid electrolytic capacitor.

(Example 10)
A solid electrolytic capacitor was produced in the same manner as in Example 9, except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with 2,2-bis (hydroxymethyl) butyric acid.

(Example 11)
A solid was obtained in the same manner as in Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with N- [tris (hydroxymethyl) methyl] glycine (manufactured by Tokyo Chemical Industry Co., Ltd.). An electrolytic capacitor was produced.

(Example 12)
The same as Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with 3-hydroxy-2,2-bis (hydroxymethyl) propanoic acid (manufactured by Aldrich). Thus, a solid electrolytic capacitor was produced.

(Example 13)
Solid electrolytic capacitor in the same manner as in Example 9, except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with 4-hydroxy-3- (hydroxymethyl) -3-methylbutanoic acid Was made.

(Example 14)
A solid electrolytic capacitor was produced in the same manner as in Example 9, except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 9.

(Example 15)
A solid electrolytic capacitor was produced in the same manner as in Example 10 except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 10.

(Example 16)
A solid electrolytic capacitor was produced in the same manner as in Example 11 except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 11.

(Example 17)
Example 10 except that 1 part of triethylamine was added to the conductive polymer dispersion for producing a solid electrolytic capacitor described in Example 10 and 8 parts of ethylene glycol and 2 parts of polyethylene glycol were used instead of 10 parts of ethylene glycol. A solid electrolytic capacitor was produced in the same manner as described above.

(Comparative Example 6)
A solid electrolytic capacitor was produced in the same manner as in Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was not used.

(Comparative Example 7)
A solid electrolytic capacitor was produced in the same manner as in Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with pentaerythritol.

(Comparative Example 8)
A solid electrolytic capacitor was produced in the same manner as in Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with pentaglycerol.

(Comparative Example 9)
A solid electrolytic capacitor was produced in the same manner as in Example 9, except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with tris (hydroxymethyl) aminomethane (manufactured by Tokyo Chemical Industry Co., Ltd.). did.

(Comparative Example 10)
A solid electrolytic capacitor was produced in the same manner as in Example 9 except that 2,2-bis (hydroxymethyl) propionic acid described in Example 9 was replaced with 2-hydroxymethylbenzoic acid.

<Evaluation of ESR and charge / discharge characteristics of solid electrolytic capacitor>
For the solid electrolytic capacitors obtained from Examples 9 to 17 and Comparative Examples 6 to 10, the equivalent series resistance (ESR) at 100 kHz was measured, and ESR after a high temperature load test (maintained in an atmosphere at a temperature of 120 ° C. for 100 hours) Was measured.

Moreover, the charge / discharge characteristic was measured about the solid electrolytic capacitor obtained from Examples 9-17 and Comparative Examples 6-10. The charge / discharge characteristics of the solid electrolytic capacitor were evaluated by measuring the initial capacitance and the capacitance after 10,000 cycles according to the conditions of the following charge / discharge characteristics test to determine the rate of change. Table 2 shows the measurement results of ESR and charge / discharge characteristics. Abbreviations in the table are as described above.
Conditions for charge / discharge characteristics test Applied voltage: 50V
Charging / discharging resistance: 1 kΩ
Temperature: 105 ° C
Charging / discharging cycle: 30 seconds charging, 30 seconds discharging as one cycle

From Table 2, it can be seen that Examples 9 to 17 are superior to Comparative Examples 6 to 10 in ESR and charge / discharge characteristics in the solid electrolytic capacitor. In particular, it can be seen that a solid electrolytic capacitor produced using a conductive polymer dispersion for producing a solid electrolytic capacitor containing triethylamine is more excellent in ESR and charge / discharge characteristics.
Moreover, when Examples 1-8 are compared with Examples 9-17, it turns out that the electrostatic capacitance of a solid electrolytic capacitor improves when the polyaniline layer is formed on the valve action metal.

  Since the solid electrolytic capacitor produced using the conductive polymer dispersion for producing the solid electrolytic capacitor of the present invention is excellent in equivalent series voltage and charge / discharge characteristics, it can be applied to high-frequency digital devices and the like.

Claims (12)

A conductive polymer dispersion for producing a solid electrolytic capacitor, comprising at least a compound represented by the following general formula (1), a conductive polymer, and a dispersion medium.

(In the formula (1), R ₁ represents any _one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents a hydrocarbon having 0 to 6 carbon atoms. Represents a group or an amino group, where the number of carbon atoms of 0 means that C and COOH are directly bonded.) The conductive polymer dispersion for producing a solid electrolytic capacitor according to claim 1, wherein the compound represented by the general formula (1) is the following compound (A) or (B).

  3. The solid according to claim 1, wherein the content of the compound represented by the general formula (1) in the conductive polymer dispersion for producing a solid electrolytic capacitor is 0.01 to 20% by mass. Conductive polymer dispersion for manufacturing electrolytic capacitors.   The conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of claims 1 to 3, wherein the conductive polymer is a polythiophene.   The conductive polymer dispersion for producing a solid electrolytic capacitor according to claim 4, wherein the dopant component constituting the polythiophene is polystyrene sulfonic acid.   6. The conductive polymer dispersion for producing a solid electrolytic capacitor according to claim 1, comprising at least one selected from the group consisting of ethylene glycol, γ-butyrolactone, and polyethylene glycol. .   The conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of claims 1 to 6, further comprising an alkaline compound.   The conductive polymer dispersion for producing a solid electrolytic capacitor according to claim 7, wherein the alkaline compound is a tertiary amine.   A valve having a dielectric oxide film after the valve action metal having a dielectric oxide film is dipped and pulled up in the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of claims 1 to 8. The conductive metal is coated with the conductive polymer dispersion for producing a solid electrolytic capacitor according to any one of claims 1 to 8 on the working metal, and then dried, and the conductive metal is coated on the valve working metal having a dielectric oxide film. A method for producing a solid electrolytic capacitor comprising a step of forming a solid electrolyte layer containing molecules. In the method of manufacturing a solid electrolytic capacitor having a step of forming a conductive polymer layer on a valve action metal on which a dielectric oxide film is formed,
The step of forming the conductive polymer layer includes
A step of bringing the polyaniline solution into contact with the valve action metal on which the dielectric oxide film is formed, followed by heating and drying to form a polyaniline layer on the valve action metal;
The valve action which has a dielectric oxide film, after immersing and pulling up the valve action metal which has a polyaniline layer in the conductive polymer dispersion for solid electrolytic capacitor manufacture according to any one of claims 1 to 8 The conductive polymer dispersion for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 8 is applied to a metal and then dried to contain the conductive polymer on the valve metal having a polyaniline layer. Forming a solid electrolyte layer,
A method for producing a solid electrolytic capacitor, comprising: In a solid electrolytic capacitor having a solid electrolyte layer containing a conductive polymer on a valve action metal having a dielectric oxide film,
A solid electrolytic capacitor, wherein the solid electrolyte layer containing a conductive polymer contains at least a conductive polymer and a compound represented by the following general formula (1).

(In the formula (1), R ₁ represents any _one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms, and R ₂ represents a hydrocarbon having 0 to 6 carbon atoms. Represents a group or an amino group, where the number of carbon atoms of 0 means that C and COOH are directly bonded.) The solid electrolytic capacitor according to claim 11, wherein the compound represented by the general formula (1) is the following compound (A) or (B).