JP2017174916A - Solid electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor having excellent ESR characteristics and an excellent withstand voltage, and a method of manufacturing the same.SOLUTION: The solid electrolytic capacitor has a conductive polymer-containing solid electrolyte layer on a valve action metal having a dielectric oxide film. The conductive polymer-containing solid electrolyte layer contains at least a conductive polymer and a polyoxyethylene-polyoxypropylene block polymer having a polyoxyethylene group and a polyoxypropylene group. The method of manufacturing the solid electrolytic capacitor is also provided.SELECTED DRAWING: None

Description

  The present invention relates to a solid electrolytic capacitor and a method for manufacturing 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. In the chemical oxidative polymerization method, for example, an oxidant is deposited on a valve action metal on which a dielectric oxide film is formed, and then contacted with a solution containing the monomer compound, followed by a heat treatment, whereby the monomer compound is treated. By performing chemical oxidative polymerization, a solid electrolyte layer having a conductive polymer can be formed on a valve action metal having a dielectric oxide film.

  However, this chemical oxidative polymerization method has a problem that the withstand voltage of the solid electrolytic capacitor is lowered because the pressure resistance of the generated polymer is not high and the acid or iron generated during the chemical oxidative polymerization affects the oxide film. .

Patent Document 1 discloses a solid electrolytic capacitor in which a capacitor element contains a compound having a polyvinyl ether skeleton together with a conductive polymer. There is a description that a solid electrolytic capacitor manufactured using a compound having a polyvinyl ether skeleton has realized low ESR, low leakage current, and high breakdown voltage.
However, although the solid electrolytic capacitor has a low ESR and a low leakage current, there is a problem that a sufficient withstand voltage has not yet been obtained, and further reduction in ESR has been demanded.

  From the above, a solid electrolytic capacitor having excellent ESR characteristics and excellent withstand voltage and a method for manufacturing the same have been demanded.

JP 2008-85114 A

  The objective of this invention is providing the solid electrolytic capacitor which has the outstanding ESR characteristic, and the withstand voltage, and its manufacturing method.

  In the solid electrolytic capacitor having a solid electrolyte layer containing a conductive polymer on a valve action metal having a dielectric oxide film, the present inventors have found that the solid electrolyte layer containing a conductive polymer is highly conductive. A solid electrolytic capacitor containing at least a molecule and a polyoxyethylene polyoxypropylene block polymer having a polyoxyethylene group and a polyoxypropylene group has been found to be able to solve the above problems, and the present invention has been completed. It was.

  That is, the present invention is as follows.

The first 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 polyoxyethylene polyoxypropylene block polymer having a polyoxyethylene group and a polyoxypropylene group It is an electrolytic capacitor.

  A second invention is the solid electrolytic capacitor according to the first invention, wherein the polyoxyethylene polyoxypropylene block polymer is a compound represented by the following general formula (1).

（式（１）中、ｍ、ｎ、ｌはそれぞれ独立して１〜７００の整数を示す。）

(In formula (1), m, n, and l each independently represent an integer of 1 to 700.)

  A third invention is the solid electrolytic capacitor according to the first or second invention, wherein the polyoxyethylene polyoxypropylene block polymer has an average molecular weight of 800 to 20,000.

  According to a fourth invention, in any one of the first to third inventions, the content of the polyoxyethylene polyoxypropylene block polymer in the solid electrolyte is 0.01 to 30% by mass. It is a solid electrolytic capacitor of description.

  According to a fifth invention, the conductive polymer is a conductive polymer having a polymer of a thiophene compound represented by the following general formula (2) and a dopant. It is a solid electrolytic capacitor as described in any one of these.

（式（２）中、Ｒaは水素原子又は炭素数１〜６の直鎖又は分岐状のアルキル基を示し、Ｘはそれぞれ同一でも異なっていても良い炭素原子又は硫黄原子を示す。）

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a carbon atom or a sulfur atom which may be the same or different.)

  A sixth invention is characterized in that the dopant is at least one selected from polystyrenesulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, methoxybenzenesulfonic acid, ethoxybenzenesulfonic acid, and xylenesulfonic acid. It is a solid electrolytic capacitor described in the invention.

  A seventh invention is a monomer liquid comprising a monomer compound, a polyoxyethylene polyoxypropylene block polymer, and an organic solvent.

  An eighth invention is the monomer liquid according to the seventh invention, wherein the polyoxyethylene polyoxypropylene block polymer is a compound represented by the following general formula (1).

（式（１）中、ｍ、ｎ、ｌはそれぞれ独立して１〜７００の整数を示す。）

(In formula (1), m, n, and l each independently represent an integer of 1 to 700.)

  A ninth invention is the monomer liquid according to the seventh or eighth invention, wherein the molecular weight of the polyoxyethylene polyoxypropylene block polymer is 800 to 20,000.

  A tenth invention is the monomer liquid according to any one of the seventh to ninth inventions, wherein the monomer compound is represented by the following general formula (2).

（式（２）中、Ｒaは水素原子又は炭素数１〜６の直鎖又は分岐状のアルキル基を示し、Ｘはそれぞれ同一でも異なっていても良い炭素原子又は硫黄原子を示す。）

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a carbon atom or a sulfur atom which may be the same or different.)

The eleventh invention is a method for producing a solid electrolytic capacitor comprising a solid electrolyte layer having a conductive polymer on a valve metal having a dielectric oxide film formed thereon.
The monomer liquid according to any one of the seventh to tenth inventions, and the oxidant solution containing the dopant, the oxidant, and the organic solvent are brought into contact with the valve action metal on which the dielectric oxide film is formed. The solid electrolytic capacitor manufacturing method includes a step of performing a chemical oxidation polymerization to form a solid electrolyte layer having a conductive polymer on a valve action metal on which a dielectric oxide film is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the solid electrolytic capacitor which has the outstanding ESR characteristic and withstand voltage, and its manufacturing method can be provided.

  First, the solid electrolytic capacitor of the present invention will be described.

<Solid electrolytic capacitor>
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. And a polyoxyethylene polyoxypropylene block polymer having a polyoxyethylene group and a polyoxypropylene group.

<Polyoxyethylene polyoxypropylene block polymer>
A polyoxyethylene polyoxypropylene block polymer that is a block polymer having a polyoxyethylene group that is a hydrophilic group and a polyoxypropylene group that is a hydrophobic group is used.

  The presence of the hydrophilic group and the hydrophobic group improves the ESR characteristics by improving the adhesion with the aluminum surface, and the hydrophobic group improves the polymer pressure resistance obtained by chemical polymerization. It is possible to improve the withstand voltage of the capacitor.

  Preferably, the polyoxyethylene polyoxypropylene block polymer is a compound represented by the following general formula (1).

  In general formula (1), m, n, and l each independently represent an integer of 1 to 700.

  The degree of polymerization of the polyoxyethylene polyoxypropylene block polymer (n in the above formula (1)) and the addition amount of polyethylene oxide (m + l in the above formula (1)) are not particularly limited, depending on the use conditions, purpose, etc. It can be selected as appropriate.

  As polyoxyethylene polyoxypropylene block polymer, BASF Japan Co., Ltd. Pluronic (registered trademark) series, Sanyo Chemical Industry Co., Ltd. New Paul (registered trademark) PE series, Asahi Denka Kogyo Co., Ltd. Examples include Adeka Pluronic (registered trademark) L or F series, Epan (registered trademark) series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Pronon (registered trademark) series or Unilube (registered trademark) manufactured by NOF Corporation. These may be used alone or in combination of two or more.

  The number average molecular weight of the polyoxyethylene polyoxypropylene block polymer is preferably from 500 to 80,000, particularly preferably from 800 to 20,000. Outside of this range, that is, when the number average molecular weight is less than 500, the reliability is poor, and when it exceeds 80,000, there is a problem that impregnation into the device is lost.

  The content of the polyoxyethylene polyoxypropylene block polymer in the solid electrolyte can be adjusted by the content of the polyoxyethylene polyoxypropylene block polymer in the monomer solution used and the oxidant solution. That is, when the total amount other than the organic solvent in the monomer solution and oxidant solution used is 100 parts by mass, by adjusting the content of the polyoxyethylene polyoxypropylene block polymer to 0.01 to 30 parts by mass, Content of the polyoxyethylene polyoxypropylene block polymer in the obtained solid electrolyte can be adjusted to 0.01-30 mass%.

(Conductive polymer)
The conductive polymer used in the present invention is a polymer doped with a dopant. The monomer compound used for producing the polymer is not particularly limited, and for example, pyrroles, thiophenes, anilines, etc. can be used, but a conductive polymer having excellent conductivity is obtained. Therefore, it is preferably a thiophene compound represented by the following general formula (2).

  In the general formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a carbon atom or a sulfur atom which may be the same or different.

  Specific examples of the thiophene compound represented by the general formula (2) include 3,4-ethylenedioxythiophene, methyl-3,4-ethylenedioxythiophene, ethyl-3,4-ethylenedioxythiophene, Propyl-3,4-ethylenedioxythiophene, 3,4-propylenedioxythiophene, methyl-3,4-propylenedioxythiophene, ethyl-3,4-propylenedioxythiophene, propyl-3,4-propylenedi Oxythiophene, 3,4-ethylenedithiathiophene, methyl-3,4-ethylenedithiathiophene, ethyl-3,4-ethylenedithiathiophene, propyl-3,4-ethylenedithiathiophene, 3,4-propylene Dithiathiophene, methyl-3,4-propylene dithiathiophene, ethyl-3,4 Propylene dithiastannolane thiophene, propyl-3,4-propylene di-thia thiophene and the like.

  Among these, 3,4-ethylenedioxythiophene, methyl-3,4-ethylenedioxythiophene, and ethyl-3,4-ethylenedioxythiophene are particularly preferable from the viewpoint of excellent electrical characteristics particularly in the solid electrolytic capacitor. It is done.

  The conductive polymer used in the present invention can be obtained by chemical oxidative polymerization of a monomer compound such as the thiophene compound represented by the general formula (2) in the presence of the dopant.

  The dopant 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.

  Examples of the dopant include halogen ions such as iodine, bromine, and chlorine, halide ions such as hexafluorophosphorus, hexafluoroarsenic, hexafluoroantimony, tetrafluoroboron, and perchloric acid, or methanesulfonic acid, dodecylsulfonic acid, and the like. Cyclic sulfonate ions such as alkyl-substituted organic sulfonate ions and camphor sulfonate ions, or alkyl-substituted or unsubstituted benzene mono- or disulfonate ions such as benzene sulfonic acid, para-toluene sulfonic acid, dodecyl benzene sulfonic acid, and benzene disulfonic acid Alkyl substituted or unsubstituted ions of naphthalenesulfonic acid substituted with 1 to 4 sulfonic acid groups such as 2-naphthalenesulfonic acid and 1,7-naphthalenedisulfonic acid, anthracenesulfonic acid ion, anthracene Non-sulfonate ions, alkyl-substituted or unsubstituted biphenyl sulfonate ions such as alkylbiphenyl sulfonate and biphenyl disulfonate, polymer sulfonate ions such as polystyrene sulfonate and naphthalene sulfonate formalin condensate, etc., or molybdophosphate and tongue Examples include heteropolyacid ions such as strinic acid and tungstomolybdophosphoric acid, methoxybenzenesulfonic acid, ethoxybenzenesulfonic acid, and xylenesulfonic acid. These may be a single polymer or two or more types of copolymers. Among these, at least one selected from polystyrenesulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, methoxybenzenesulfonic acid, ethoxybenzenesulfonic acid, and xylenesulfonic acid is more preferable, and polystyrenesulfonic 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).

The content of the polyoxyethylene polyoxypropylene block polymer in the solid electrolyte is preferably 0.01 to 30% by mass, more preferably 1 to 20% by mass, and particularly preferably 5 to 15% by mass.
If the amount is less than 0.01% by mass, the added amount is small and the characteristics cannot be sufficiently extracted. If the amount exceeds 30% by mass, the characteristics cannot be sufficiently extracted due to a decrease in the dopant amount.

Further, for the purpose of further improving the withstand voltage of the solid electrolytic capacitor, an additive may be contained in the solid electrolyte layer.
Examples of the additive include a phosphoric acid compound and colloidal silica. Among these, colloidal silica is preferable because it is particularly excellent in the effect of improving the withstand voltage.

  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 includes a polyoxyethylene polyoxypropylene block polymer in a solid electrolyte layer containing a conductive polymer, thereby interacting with the conductive polymer and the valve metal, and having excellent ESR and Withstand voltage can be obtained.

<Monomer solution>
In the solid electrolytic capacitor of the present invention, a solid electrolyte layer obtained by chemical oxidative polymerization using a monomer solution described below and an oxidant solution described later is formed on a valve action metal having a dielectric oxide film. It is characterized by using a capacitor element.

  The monomer liquid is a monomer liquid characterized by containing a monomer compound, a polyoxyethylene polyoxypropylene block polymer, and an organic solvent.

  In addition, the compound mentioned above can be used for a monomer compound, a polyoxyethiolene polyoxypropylene block polymer, and a dopant.

  As the organic solvent, alcohol solvents such as methanol, ethanol, n-propanol, i-propanol and n-butanol are suitable.

  Moreover, in order to manufacture the solid electrolytic capacitor of this invention, it can manufacture using the monomer liquid mentioned above and the oxidizing agent solution described below.

  The oxidant solution contains a dopant, an oxidant, and an organic solvent.

  The dopant mentioned above can be used for a dopant.

Examples of the oxidizing agent include iodine, bromine, bromine iodide, chlorine dioxide, iodic acid, periodic acid, chlorous acid, and other halides, antimony pentafluoride, phosphorus pentachloride, phosphorus pentafluoride, aluminum chloride, Metal halides such as molybdenum chloride, permanganate, dichromate, chromic anhydride, ferric salt, cupric salt and other high-valent metal ion salts, sulfuric acid, nitric acid, trifluoromethane sulfuric acid, etc. Protonic acid, sulfur trioxide, nitrogen dioxide and other oxygen compounds, hydrogen peroxide, ammonium persulfate, peroxo acids such as sodium perborate, salts of the peroxo acids, molybdophosphoric acid, tungstophosphoric acid, tungstomolybdophosphoric acid And the like, and salts of the heteropolyacid.
The oxidizing agent can be used alone or in combination of two or more.

  As the organic solvent, alcohol solvents such as methanol, ethanol, n-propanol, i-propanol and n-butanol are suitable.

  The dopant and oxidizing agent used in the present invention may be a dopant / oxidizing agent.

  The dopant and oxidant is an oxidant compound containing an anion that becomes a dopant of the conductive polymer. By using such a compound, the anion is incorporated into the conductive polymer during chemical oxidative polymerization. A conductive polymer that functions as a dopant and has improved conductivity can be formed.

Preferable anions include organic acid ions such as organic sulfonate ions and carboxylate ions, inorganic acid ions such as boron compound ions, phosphate compound ions, and perchlorate ions.
Particularly suitable as oxidizing agents containing such anions include iron salts of inorganic acids such as ferric chloride and ferric perchlorate, ferric benzenesulfonate, and ferric p-toluenesulfonate. Organic sulfonic acid ferric salts such as salts and alkylnaphthalene sulfonic acid ferric salts can be exemplified, and most preferable examples include organic sulfonic acid ferric salts.

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

  In a method of manufacturing a solid electrolytic capacitor having a solid electrolyte layer having a conductive polymer on a valve action metal on which a dielectric oxide film is formed, the above-described monomer solution and the above-described oxidant solution are subjected to dielectric oxidation. It has a step of performing chemical oxidative polymerization in contact with a valve action metal on which a film is formed, and forming a solid electrolyte layer having a conductive polymer on the valve action metal on which a dielectric oxide film is formed. It is a manufacturing method of a solid electrolytic capacitor.

The step of chemical oxidation polymerization using the monomer solution and the oxidant solution described above to form a solid electrolyte layer having a conductive polymer on the valve action metal on which the dielectric oxide film is formed will be described in detail. ,
1. A solution prepared by mixing a monomer liquid containing a polyoxyethylene polyoxypropylene block polymer and a monomer compound and an oxidant solution containing a dopant and an oxidant is prepared, and the liquid is contacted by applying or dipping the valve metal. And forming a solid electrolyte layer containing a conductive polymer,
2. Prepare a monomer liquid containing a polyoxyethylene polyoxypropylene block polymer and a monomer compound, separately prepare an oxidizer solution containing a dopant and an oxidant, and contain the polyoxyethylene polyoxypropylene block polymer and the monomer compound. A method of forming a solid electrolyte layer having a conductive polymer by applying or immersing a valve action metal impregnated and held in a monomer solution in the oxidant solution and bringing it into contact;
3. A metal solution containing a polyoxyethylene polyoxypropylene block polymer and a monomer compound is applied or immersed in a valve metal that has been coated or impregnated and held with an oxidant solution containing a dopant and an oxidant, and contacted to conduct electricity. And a method of forming a solid electrolyte layer having a conductive polymer.

Moreover, when performing the said chemical oxidation polymerization, the solid electrolyte layer which has a conductive polymer can be formed by hold | maintaining for a predetermined time at predetermined temperature.
Here, the predetermined temperature can be arbitrarily selected in the range of 0 to 250 ° C., and the predetermined time can be arbitrarily selected in the range of 1 minute to 24 hours.

  Hereinafter, a method for producing an aluminum wound capacitor will be described as a specific example of the method for producing a solid electrolytic capacitor of the present invention.

  First, the surface of the aluminum foil serving as the anode is roughened by etching, and then an anode lead is connected, followed by chemical conversion treatment in an aqueous solution of diammonium adipate or the like to form a dielectric oxide film. In practicing the present invention, a solid electrolytic capacitor having a large capacitance can be obtained by using a foil having a large etching magnification, which is preferable.

  Separately, a separator such as Manila paper is sandwiched between the facing cathode aluminum foil to which the cathode lead is connected and the anode aluminum foil, wound up into a cylindrical shape, and then carbonized by heat treatment to wind the dielectric. A valve metal having a body oxide film is prepared.

Next, a solid electrolyte layer containing a conductive polymer is formed on the valve action metal having the dielectric oxide film. As a method of forming the solid electrolyte layer, a valve action metal having a dielectric oxide film is impregnated with a monomer solution containing a polyoxyethylene polyoxypropylene block polymer and a monomer compound by a method such as immersion, coating, spraying, and the like. Then, the impregnated monomer compound is subjected to chemical oxidative polymerization by bringing an oxidant solution into contact therewith to form a solid electrolyte layer.
In addition, a method of impregnating the oxidant solution first and then contacting the monomer liquid to perform chemical oxidative polymerization, or a method of impregnating a solution obtained by mixing the monomer liquid and oxidant solution at a time to perform chemical oxidative polymerization is also applied. Yes, it is not particularly limited. The chemical oxidative polymerization is performed at a temperature of 0 to 250 ° C., preferably in a liquid phase. If it is less than 0 ° C., chemical oxidative polymerization hardly occurs, and if it exceeds 250 ° C., the capacitor characteristics may be deteriorated.

  The impregnation and heating steps may be repeated a plurality of times.

  Next, an epoxy resin or the like is used to seal the capacitor case, and voltage is applied to perform aging to complete the solid electrolytic capacitor of the present invention.

  The solid electrolytic capacitor of the present invention uses a capacitor element having a solid electrolyte layer containing a polyoxyethylene polyoxypropylene block polymer and a conductive polymer, and has electrical characteristics excellent in ESR and withstand voltage. .

  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 solid electrolytic capacitors)
After roughening the surface of the aluminum foil by etching, the anode lead is connected by caulking, and then subjected to chemical conversion treatment in a 10% aqueous diammonium adipate solution at a voltage of 90 V to form a dielectric oxide film on the surface. Formed.

  Next, a 50 μm-thick manila paper is sandwiched as a separator between the anode foil and the counter cathode aluminum foil in which the cathode lead is connected by resistance welding, and wound into a cylindrical shape. The capacitor element was prepared by heat treating for a minute to carbonize the Manila paper. The capacitance of the obtained capacitor element in a 15% aqueous solution of diammonium adipate was 70 μF.

  Next, 2,3-dihydrothieno [3,4-b] -1,4-dioxin (EDOT) as a monomer, 60% p-toluenesulfonic acid ferric acid / ethanol solution as an oxidizing agent, polyoxy Epan (registered trademark) 410 (Daiichi Kogyo Seiyaku Co., Ltd.) was prepared as an ethylene polyoxypropylene block polymer, and the capacitor element was added to a solution prepared by mixing the three weight ratios to 1: 2.5: 0.1. Was immersed for 120 seconds, heated at 45 ° C. for 35 minutes, and then at 125 ° C. for 1 hour to perform chemical oxidative polymerization to produce a capacitor element.

  Subsequently, the capacitor case was sealed with an epoxy resin, and aging was performed by applying a voltage of 50 V to both electrodes to complete a solid electrolytic capacitor.

(Examples 2 to 4)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that the content of Epan (registered trademark) 410 (Daiichi Kogyo Seiyaku Co., Ltd.) was described in Table 1.

(Example 5)
A solid electrolytic capacitor was prepared in the same manner as in Example 1 except that Epan (registered trademark) 410 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was replaced with Unilube 70DP-950B (manufactured by NOF Corporation) corresponding to Table 1. Produced.

(Comparative Example 1)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that Epan (registered trademark) 410 (Daiichi Kogyo Seiyaku Co., Ltd.) described in Example 1 was not used.

<Evaluation of ESR of solid electrolytic capacitor>
For the solid electrolytic capacitors obtained from Examples 1 to 5 and Comparative Example 1, ESR was measured at 100 kHz. The measurement results are shown in Table 1.

<Evaluation of withstand voltage of solid electrolytic capacitor>
With respect to the solid electrolytic capacitors obtained from Examples 1 to 5 and Comparative Example 1, the withstand voltage was measured. The method of measuring the withstand voltage in a solid electrolytic capacitor is to apply a DC voltage to both electrodes, boost the voltage at a rate of 0.2 V / sec, measure the voltage when the current value reaches 0.5 mA, and Is a withstand voltage. The measurement results are shown in Table 1.

Abbreviations in Table 1 are as follows.
Compound A: (trade name) Epan (registered trademark) 410 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trioxy-polyoxyethylene molecular weight 130, polyoxypropylene molecular weight 1200)
Compound B: (trade name) Unilube (registered trademark) 70DP-950B (manufactured by NOF Corporation, triblock body having an average molecular weight of 18,000 and having a polyoxyethylene number of 200 and a polyoxypropylene number of 70)

  From Table 1, it can be seen that Examples 1 to 5 are superior to Comparative Example 1 in ESR and withstand voltage in solid electrolytic capacitors. Among the examples, it can be seen that Example 2 is particularly excellent in ESR and withstand voltage.

  Since the solid electrolytic capacitor of the present invention is excellent in ESR characteristics and withstand voltage, it can be applied to various devices such as high-frequency digital devices.

（式（２）中、Ｒaは水素原子又は炭素数１〜６の直鎖又は分岐状のアルキル基を示し、Ｘはそれぞれ同一でも異なっていても良い酸素原子又は硫黄原子を示す。）

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents an oxygen atom or a sulfur atom which may be the same or different.)

（式（２）中、Ｒaは水素原子又は炭素数１〜６の直鎖又は分岐状のアルキル基を示し、Ｘはそれぞれ同一でも異なっていても良い酸素原子又は硫黄原子を示す。）

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents an oxygen atom or a sulfur atom which may be the same or different.)

In the general formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents an oxygen atom or a sulfur atom which may be the same or different.

Claims (11)

In 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 polyoxyethylene polyoxypropylene block polymer having a polyoxyethylene group and a polyoxypropylene group Electrolytic capacitor. The solid electrolytic capacitor according to claim 1, wherein the polyoxyethylene polyoxypropylene block polymer is a compound represented by the following general formula (1).

(In formula (1), m, n, and l each independently represent an integer of 1 to 700.)   3. The solid electrolytic capacitor according to claim 1, wherein the polyoxyethylene polyoxypropylene block polymer has an average molecular weight of 800 to 20,000.   The solid electrolytic capacitor according to any one of claims 1 to 3, wherein the content of the polyoxyethylene polyoxypropylene block polymer in the solid electrolyte is 0.01 to 30% by mass. 5. The conductive polymer according to claim 1, wherein the conductive polymer is a conductive polymer having a polymer of a thiophene compound represented by the following general formula (2) and a dopant. Solid electrolytic capacitor.

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a carbon atom or a sulfur atom which may be the same or different.)   6. The solid electrolytic capacitor according to claim 5, wherein the dopant is at least one selected from polystyrenesulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, methoxybenzenesulfonic acid, ethoxybenzenesulfonic acid, and xylenesulfonic acid. .   A monomer liquid comprising a monomer compound, a polyoxyethylene polyoxypropylene block polymer, and an organic solvent. The monomer liquid according to claim 7, wherein the polyoxyethylene polyoxypropylene block polymer is a compound represented by the following general formula (1).

(In formula (1), m, n, and l each independently represent an integer of 1 to 700.)   The monomer liquid according to claim 7 or 8, wherein the molecular weight of the polyoxyethylene polyoxypropylene block polymer is from 800 to 20,000. The monomer solution according to any one of claims 7 to 9, wherein the monomer compound is represented by the following general formula (2).

(In the formula (2), Ra represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a carbon atom or a sulfur atom which may be the same or different.) In a method for producing a solid electrolytic capacitor comprising a solid electrolyte layer having a conductive polymer on a valve action metal on which a dielectric oxide film is formed,
By contacting the monomer solution according to any one of claims 7 to 10, and an oxidant solution containing a dopant, an oxidant, and an organic solvent, with a valve action metal on which a dielectric oxide film is formed. A method for producing a solid electrolytic capacitor, comprising a step of performing a chemical oxidative polymerization to form a solid electrolyte layer having a conductive polymer on a valve metal having a dielectric oxide film formed thereon.