JP2010267868A - Solid electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electropolymerized liquid for forming a conductive polymer which provides a conductive polymer with high conductivity; and to provide a method of manufacturing a solid electrolytic capacitor which obtains excellent ESR by using the electropolymerized liquid. <P>SOLUTION: In the method of manufacturing a solid electrolytic capacitor, when alkyl naphthalene sulfonic acid or its salt is used as a supporting electrolyte of the electropolymerized liquid for forming the conductive polymer, a conductive polymer film with excellent conductivity, and excellent initial characteristics of ESR are obtained by adding polyvinyl alcohol. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrolytic polymerization solution for forming a conductive polymer and a method for producing a solid electrolytic capacitor formed using the same.

  A solid electrolytic capacitor in which a dielectric oxide film is formed on the surface of a valve metal such as aluminum or tantalum, and a conductive polymer having a high electrical conductivity is formed on the dielectric oxide film as a solid electrolyte has a capacitance. (Hereinafter abbreviated as “Cs”) is known to have excellent electrical characteristics with a high equivalent series resistance (hereinafter abbreviated as “ESR”).

  In general, the solid electrolytic capacitor has a valve-acting metal foil whose surface area is enlarged by etching treatment or a sintered body whose surface area is enlarged by sintering particles of valve-acting metal, and a dielectric material on the surface by chemical conversion treatment. An oxide film is formed, then a solid electrolyte layer is formed on the dielectric oxide film, a conductive layer made of carbon and silver paste is sequentially formed, and then connected to an external terminal such as a lead frame, by transfer molding or the like It is commercialized with an exterior.

  The ESR of a solid electrolytic capacitor is mainly composed of a combined resistance consisting of the specific resistance of each member constituting the capacitor and the contact resistance generated between each member constituting the capacitor. Further reduction is desired.

  Deterioration of solid electrolytic capacitors is generally due to thermal deterioration of each member constituting the capacitor and oxygen sources such as moisture entering through the exterior of the capacitor, in addition to accidents that occur accidentally. Oxidative degradation of these materials is a major factor, and against these degradation factors, improvement of the thermal durability performance of each member that forms the capacitor, especially the solid electrolyte layer, and improvement of gas barrier properties centering on exterior members, etc. Measures are being taken.

  Typical solid electrolytes used for solid electrolytic capacitors include polypyrrole and polyethylene dioxythiophene. More specifically, polypyrrole formed by electrolytic oxidation polymerization and polyethylene dioxythiophene formed by chemical oxidation polymerization Broadly divided.

  Since the solid electrolyte formed by electrolytic oxidation polymerization can form a dense film, it tends to have excellent conductivity, and is used in the manufacture of multilayer capacitors. On the other hand, chemical oxidative polymerization can be used even for devices having complicated shapes, and is therefore often used in the manufacture of winding type capacitors.

  Regarding the inherent performance of the solid electrolyte constituting the solid electrolytic capacitor, not only the type of polymer such as polypyrrole and polyethylenedioxythiophene, but also the conductivity of the solid electrolyte depends on the supporting electrolyte used when forming the solid electrolyte. It is known that performance such as thermal durability changes, and various dopants have been studied.

  In addition, it is known that the performance of an electrolytic polymerization solution used for forming a conductive polymer varies depending on additives other than the supporting electrolyte that releases the dopant.

  As disclosed in Patent Document 1, although a solid electrolytic capacitor using sodium alkylnaphthalene sulfonate as a supporting electrolyte of an electrolytic polymerization solution is described, there is a disadvantage that ESR is inferior.

Japanese Patent Laid-Open No. 05-021280

  An object of the present invention is to provide an electropolymerization liquid for forming a conductive polymer that gives a conductive polymer with high conductivity, and a solid electrolytic capacitor in which an excellent ESR can be obtained by using the electropolymerization liquid It is to provide a manufacturing method.

  As a result of intensive studies, the inventors have found that when alkyl naphthalene sulfonic acid or a salt thereof is used as a supporting electrolyte of an electrolytic polymerization solution, the initial characteristics of ESR as a solid electrolytic capacitor are excellent by adding polyvinyl alcohol. The headline and the present invention were completed.

  Hereinafter, the present invention will be described in detail.

  The first invention is an electropolymerization liquid for forming a conductive polymer in which a conductive polymer monomer and a supporting electrolyte are dissolved in a solvent, alkylnaphthalenesulfonic acid or a salt thereof as a supporting electrolyte, and an additive As an electropolymerization liquid for forming a conductive polymer, characterized in that it contains polyvinyl alcohol.

  A second invention is the electropolymerization liquid for forming a conductive polymer according to the first invention, wherein the conductive polymer monomer is pyrrole.

  A third invention is the electropolymerization liquid for forming a conductive polymer according to the first or second invention, wherein the solvent of the electropolymerization liquid for forming a conductive polymer is water.

  The fourth invention is described in any one of the first to third inventions, wherein at least one compound represented by the following general formulas (1) to (3) is dissolved as an additive. This is an electropolymerization liquid for forming a conductive polymer.

（式（１）〜（３）中、Ｒはそれぞれ同一でも異なっていてもよい、水素原子、ニトロ基、水酸基、炭素数１〜６の直鎖状又は分岐鎖状アルキル基又はフェニル基を示し、少なくとも一つはニトロ基、かつ、少なくとも一つは水酸基を示す。）

(In the formulas (1) to (3), R represents a hydrogen atom, a nitro group, a hydroxyl group, a linear or branched alkyl group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different. , At least one represents a nitro group, and at least one represents a hydroxyl group.)

  According to a fifth aspect of the present invention, in the solid electrolytic capacitor in which the dielectric oxide film is formed on the valve action metal and the solid oxide is provided on the dielectric oxide film, the solid electrolyte according to any one of the first to fourth aspects of the invention. A method for producing a solid electrolytic capacitor having an emperor that forms a conductive polymer by electrolytic polymerization in an electrolytic polymerization solution for forming a conductive polymer.

  According to a sixth aspect of the present invention, there is provided a step of forming the preliminary conductive layer (A) on the valve action metal on which the dielectric oxide film is formed, and any one of the first to fourth aspects of the invention on the preliminary conductive layer (A). And forming a conductive polymer layer (B) by electrolytic polymerization in the electropolymerization liquid for forming a conductive polymer.

  7th invention is a manufacturing method of the solid electrolytic capacitor as described in 6th invention, wherein a preliminary conductive layer (A) contains a manganese dioxide layer.

  According to an eighth aspect of the invention, the preliminary conductive layer (A) contains a conductive polymer layer formed by applying a solution containing a solvent-soluble or solvent-dispersible conductive polymer and then drying the solution. It is the manufacturing method of the solid electrolytic capacitor as described in 6th invention characterized by the above-mentioned.

  According to a ninth invention, the preliminary electroconductive layer (A) contains a conductive polymer layer formed by chemical polymerization of a conductive polymer monomer, and the solid electrolysis according to the sixth invention This is a method of manufacturing a capacitor.

A tenth aspect of the present invention is a solid electrolytic capacitor having a conductive polymer layer on a dielectric oxide film on a valve action metal surface.
The solid electrolytic capacitor is characterized in that the conductive polymer layer is composed of a composite layer containing polyvinyl alcohol and a conductive polymer.

  An eleventh invention is the solid electrolytic capacitor according to the tenth invention obtained by the method for producing a solid electrolytic capacitor according to any of the fifth to ninth inventions.

  ADVANTAGE OF THE INVENTION According to this invention, the electropolymerization liquid for electroconductive polymer formation which gives the electroconductive polymer of higher electroconductivity than before can be provided, and ESR which is remarkably superior compared with the conventional solid electrolytic capacitor is shown. A method of manufacturing a solid electrolytic capacitor can be provided.

  First, the electropolymerization liquid for forming a conductive polymer of the present invention will be described.

  In the electropolymerization liquid for forming a conductive polymer of the present invention, an alkylnaphthalenesulfonic acid or a salt thereof, which is a supporting electrolyte capable of releasing a dopant, a monomer which is a conductive polymer monomer, and polyvinyl alcohol are dissolved in the solution. It is a thing.

  The supporting electrolyte capable of releasing the dopant is alkyl naphthalene sulfonic acid or a salt thereof, specifically, methyl naphthalene sulfonic acid, ethyl naphthalene sulfonic acid, propyl naphthalene sulfonic acid, butyl naphthalene sulfonic acid or a sodium salt thereof, A potassium salt, an ammonium salt, etc. are mentioned. In addition, you may use these support electrolytes in mixture of 2 or more types.

  The concentration of the supporting electrolyte is preferably 0.001 to 2.0 mol / L, more preferably 0.01 to 1.0 mol / L, and particularly preferably 0.05 to 0.3 mol / L. When the amount is less than 0.001 mol / L, sufficient electrical characteristics may not be obtained. When the amount exceeds 2.0 mol / L, there is a disadvantage that the economy is inferior.

  As the monomer that is the conductive polymer monomer, pyrrole, aniline, furan, thiophene, or derivatives thereof can be used. Examples of the derivatives include 3-alkylpyrrole, 3-alkylthiophene, 3,4-alkylenedioxypyrrole, 3,4-alkylenedioxythiophene. The said monomer can contain 1 type (s) or 2 or more types simultaneously. Among these, pyrrole and / or a derivative thereof are preferable from the viewpoint of toughness, conductivity and durability of the obtained conductive polymer, and pyrrole is particularly preferable.

  The concentration of the monomer that is a conductive polymer monomer is preferably 0.001 to 3.0 mol / L, more preferably 0.01 to 1.0 mol / L, and 0.1 to 0.5 mol / L. L is particularly preferable. When the amount is less than 0.001 mol / L, sufficient electric conductivity and heat resistance may not be obtained. When the amount exceeds 3.0 mol / L, there is a disadvantage that the resin is not completely dissolved and is not economical.

  The polyvinyl alcohol can be obtained by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate with an alkali or an acid.

  Polyvinyl alcohol is classified according to the degree of saponification and the degree of polymerization, and modified polyvinyl alcohol partially having sulfonic acid or carboxylic acid can be used.

  The modified polyvinyl alcohol is obtained by copolymerizing a monomer having an ethylenically unsaturated double bond and a monomer having a vinyl ester unit and then saponifying to obtain a carbonyl group-containing polyvinyl alcohol, washing and drying. An unsaturated double bond starting from a carboxyl group is randomly introduced into the main chain.

The polyvinyl alcohol used in the present invention preferably has a saponification degree of 80% or more, and has a feature that the greater the saponification degree, the greater the solubility in water.
The degree of polymerization is preferably 100 to 5000, more preferably 200 to 4000. When the ratio is less than 100, a high effect on the shrinkage rate cannot be obtained. When the ratio exceeds 5000, the viscosity increases, which is difficult to handle.

  The content of polyvinyl alcohol is preferably 0.01 to 10.0% by mass, more preferably 0.1 to 5.0% by mass, and particularly preferably 0.5 to 2.0% by mass. When the content is less than 0.01% by mass, sufficient conductivity and ESR are not improved. When the content exceeds 10.0% by mass, it takes time to dissolve and the handling is difficult because the viscosity is increased. There are drawbacks.

  In the present invention, the physical strength can be improved by adsorbing polyvinyl alcohol instead of the solvent adsorbing to the conductive polymer in the electropolymerization of the monomer, and the conductive polymer layer is hardly cracked. Therefore, it is considered that a conductive polymer film excellent in conductivity and a solid electrolytic capacitor excellent in ESR can be obtained.

  The solvent of the electropolymerization electrolytic solution used in the present invention is one in which water is used as a main solvent, or ethers such as tetrahydrofuran (THF), dioxane and diethyl ether, ketones such as acetone and methyl ethyl ketone, dimethylformamide ( DMF), acetonitrile, benzonitrile, N-methylpyrrolidone (NMP), aprotic polar solvents such as dimethyl sulfoxide (DMSO), esters such as ethyl acetate and butyl acetate, non-aromatics such as chloroform and methylene chloride Chlorine solvents, nitro compounds such as nitromethane, nitroethane and nitrobenzene, alcohols such as methanol, ethanol and propanol, organic acids such as formic acid, acetic acid and propionic acid, or acid anhydrides of such organic acids (such as acetic anhydride) 0-30% or less Mixed mixed solvent and the like. Among these, those using water alone are preferable from the viewpoint of environmental load and safety.

  An additive may be contained in the electropolymerization liquid for forming a conductive polymer of the present invention. The additive used in the present invention is preferably one having mainly the characteristics of either an antioxidant or a surfactant. More preferred as such additives are compounds represented by the following general formulas (1) to (3).

  In the above general formulas (1) to (3), R may be the same or different and each represents a hydrogen atom, a nitro group, a hydroxyl group, a linear or branched alkyl group having 1 to 6 carbon atoms, or a phenyl group. And at least one represents a nitro group and at least one represents a hydroxyl group.

Specific examples of the compound represented by the general formula (1) include, for example, 4-nitrophenol, 2-methyl-4-nitrophenol, 3-methyl-4-nitrophenol, 2-ethyl-4-nitrophenol, Examples thereof include nitrophenols such as 3-ethyl-4-nitrophenol, 2-hexyl-4-nitrophenol, and 3-hexyl-4-nitrophenol.
Specific examples of the compound represented by the general formula (2) include nitronaphthols such as 4-nitro-1-naphthol.
Specific examples of the compound represented by the general formula (3) include nitroanthraquinones such as 1-hydroxy-4-nitroanthraquinone.

  The compound represented by general formula (1)-(3) can use 1 type (s) or 2 or more types. The compounds represented by the general formulas (1) to (3) are 4-nitrophenol, 4-nitro-1-naphthol, 1-hydroxy-4-nitro from the viewpoint of thermal durability of the obtained conductive polymer. Anthraquinone is preferred.

  When the additive is contained, the additive is preferably contained at a concentration of 0.002 to 1.0 mol / L, preferably 0.003 to 0.2 mol / L. If the amount is less than 0.003 mol / L, sufficient improvement in electric characteristics is not observed, and if it exceeds 1.0 mol / L, it cannot be completely dissolved, and there is a disadvantage that it is economically inferior.

  The manufacturing method of the solid electrolytic capacitor using the electropolymerization liquid for conductive polymer formation of this invention is demonstrated.

  Solid electrolysis having a step of forming a conductive polymer layer by electrolytic polymerization in an electropolymerization liquid for forming a conductive polymer in forming a conductive polymer layer on a valve metal having a dielectric oxide film formed thereon This is a method of manufacturing a capacitor.

  Further, in the formation of the conductive polymer layer on the valve action metal on which the dielectric oxide film is formed, the step of forming the preliminary conductive layer (A), and the preliminary conductive layer (A), the claim 1 or And a step of forming the conductive polymer layer (B) by electrolytic polymerization in the electropolymerization liquid for forming a conductive polymer described in 2.

  The preliminary conductive layer (A) includes (1) a manganese dioxide layer, (2) a conductive polymer layer formed by applying and drying a solution containing a solvent-soluble or solvent-dispersible conductive polymer, ( 3) A conductive polymer layer formed by chemical polymerization of a conductive polymer monomer, characterized by containing at least these layers.

  The manganese dioxide layer in (1) is obtained by impregnating manganese nitrate and then thermally decomposing it to form a manganese dioxide layer, or by attaching a permanganate aqueous solution, overheating and reducing to form a manganese dioxide layer. Obtainable.

Specific examples of the solution containing the solvent-soluble conductive polymer in (2) include a solution obtained by dissolving 0.1 to 10% by weight of polyaniline in N-methylpyrrolidone (NMP).
The preliminary conductive layer (A) can be formed by applying such a solution onto the valve action metal on which the dielectric oxide film is formed and then drying by heating at 50 ° C. to 150 ° C.
In addition, as the solution containing the solvent-dispersible conductive polymer in (2), specifically, water or an organic solvent such as alcohol, methyl ethyl ketone, toluene, or a mixture thereof is added to polypyrrole or polyethylene dioxythiophene. Examples thereof include a solution in which coalesced fine particles are dispersed and mixed.
In addition, in this dispersion solution, the organic sulfonic acid type | system | group anion and organic polymer sulfonic acid type | system | group anion used as a dopant may contain as needed.
The preliminary conductive layer (A) can be formed by applying such a solution onto the valve action metal on which the dielectric oxide film is formed and then drying by heating at 50 ° C. to 150 ° C.

The conductive polymer layer formed by chemical oxidative polymerization of the conductive polymer monomer in (3) will be described.
Examples of the conductive polymer monomer include pyrrole or a derivative thereof, aniline or a derivative thereof, and ethylenedioxythiophene or a derivative thereof.
Examples of the chemical oxidative polymerization method include a method in which a solution containing the conductive polymer monomer and an oxidant are brought into contact with each other on a valve action metal on which a dielectric oxide film is formed to perform oxidative polymerization. It is done.
Examples of the oxidizing agent include inorganic oxidizing agents such as hydrogen peroxide, persulfate and perborate; inorganic ferric salts such as ferric chloride and ferric sulfate; An organic sulfonic acid ferric salt such as an iron salt can be used, and preferably a solution prepared by adjusting them to an appropriate concentration can be used as an oxidizing agent.
The preliminary conductive layer (A) can be formed by bringing the solution containing the conductive polymer monomer into contact with the oxidizing agent-containing solution on the valve action metal as described above.

  Next, an anode lead terminal is connected from the valve action metal, a cathode lead terminal is connected from the cathode layer, and an electrode is taken out to form an element. The entire element is made of an insulating resin such as epoxy resin or a ceramic or metal outer case. By sealing with, a solid electrolytic capacitor can be obtained.

  By using the electropolymerization liquid for forming the conductive polymer, a conductive polymer layer that is small in shrinkage and small in deformation upon drying can be obtained, and further, by using the conductive polymer layer as a solid electrolyte, heat durability can be obtained. A solid electrolytic capacitor having the following can be obtained.

  A solid electrolytic capacitor having a conductive polymer layer on a dielectric oxide film on a valve action metal surface, wherein the conductive polymer layer is composed of a composite layer containing polyvinyl alcohol and a conductive polymer. It is a capacitor.

  The composite layer is a layer composed of a preliminary conductive layer, a conductive polymer layer, and the like.

  FIG. 1 is a cross-sectional view of a solid electrolytic capacitor of the present invention. 1 is a valve metal, 2 is a dielectric oxide film, 3 is a preliminary conductive layer, and 4 is a conductive polymer layer.

  The anode valve action metal used in the present invention includes one selected from the group consisting of aluminum, tantalum, niobium and titanium, and is used in the form of a sintered body or foil.

  The solid electrolytic capacitor of the present invention can be either a chip type or a wound type depending on the type and shape of the anode valve action metal used.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(Evaluation of electropolymerized conductive polymer film)
Example 1
A substrate with a transparent conductive film made of tin-containing indium oxide having a size of 30 mm × 30 mm was prepared, washed with acetone and pure water, and then dried in a dryer at 105 ° C. for 10 minutes. Next, an electrolytic polymerization solution (sodium alkylnaphthalenesulfonate: 1.4 (mmol) + pyrrole: 0.6 (g) + polyvinyl alcohol (VF-17, manufactured by Nippon Acetate Bipoval Co., Ltd., polymerization degree 1700, Saponification degree 98.0 to 99.0 mol%): 0.5 g + H ₂ O: 45.8 (g)), and the transparent conductive film side is set as the anode, and the current value is fixed at 0.4 mA. Then, electropolymerization was performed to form a conductive polymer layer on the substrate.

  Next, the conductive polymer layer formed on the substrate with the transparent conductive film was peeled off to complete a conductive polymer film.

(Example 2)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, electrolytic polymerization solution sodium alkylphthalene sulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (JM-33, manufactured by Nihon Acetate / Poval Co., Ltd., polymerization degree 3300, Ken The degree of conversion was 93.5 to 94.5 mol%): 0.5 g + H ₂ O: 45.8 (g), and electropolymerization was performed to form a conductive polymer film.

(Example 3)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, sodium butylnaphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (JM-05, manufactured by Nippon Acetate / Poval Co., Ltd., polymerization degree 500, Ken The degree of conversion was 93.5 to 94.5 mol%): 0.5 g + H ₂ O: 45.8 (g), and electropolymerization was performed to form a conductive polymer film.

Example 4
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, sodium butylnaphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (JF-17, manufactured by Nippon Bibyo-Poval Co., Ltd., polymerization degree 1700, Ken The degree of conversion was 98 to 99 mol%): 0.5 g + H ₂ O: 45.8 (g), and electropolymerization was performed to form a conductive polymer film.

(Example 5)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, potassium methyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (JMR-10HH, polymerization degree 240, saponification degree 99 mol%): 0.5 g + H ₂ Electrolytic polymerization was performed using a mixed solution of O: 45.8 (g) to form a conductive polymer film.

(Example 6)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. In other words, potassium methyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + 4-nitrophenol 0.25 (g) + polyvinyl alcohol (JMR-10HH, Nippon Vinegar-Povar) A conductive polymer film was formed by electrolytic polymerization using a mixed solution of Co., Ltd., polymerization degree 240, saponification degree 99 mol%): 0.5 g + H ₂ O: 45.8 (g).

(Comparative Example 1)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, electrolytic polymerization is performed using a mixed solution of sodium alkylnaphthalene sulfonate: 0.4 (g) + pyrrole: 0.6 (g) + H ₂ O: 45.8 (g) as the electrolytic polymerization solution, and the conductive property. A polymer film was formed.

(Comparative Example 2)
A conductive polymer film was obtained in the same manner as in Example 1 except that the production method of the conductive polymer was changed to the following method. That is, a mixture of sodium alkylnaphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + 4-nitrophenol: 0.25 (g) + H ₂ O: 45.8 (g) in the electrolytic polymerization solution Electrolytic polymerization was performed using the liquid to form a conductive polymer film.

  The electrical conductivity of the conductive polymer films obtained from Examples 1 to 6 and Comparative Examples 1 and 2 was measured by the 4-terminal method.

  From Table 1, it was found that when alkyl naphthalene sulfonic acid was used as the supporting electrolyte, the electrical conductivity was improved by containing polyvinyl alcohol.

(Evaluation of solid electrolytic capacitors)
(Example 7)
A 3 mm × 5 mm size etched aluminum formed foil having a dielectric oxide film formed on the surface was dried in a 105 ° C. dryer for 10 minutes. This was left to stand on an 18 ° C. thermoplate for 10 minutes. Next, 4 μl of a monomer liquid (pyrrole: 3 (g) + ethanol: 5 (g) + H ₂ O: 18.4 (g) mixed liquid) cooled to 18 ° C. was dropped on the foil and left for 1 minute. did. Furthermore, an oxidizing agent solution (p-toluenesulfonate tetraethylammonium (PTS-TEA): 5.6 (mmol) + ammonium peroxodisulfate: 1.56 (g) + H ₂ O: 10.63 (g)) : 12 μl was dropped on the foil and left to stand for 10 minutes for chemical oxidative polymerization to form a precoat layer. This was washed with pure water and dried in a 105 ° C. dryer for 10 minutes.

Next, electrolytic polymerization solution (sodium alkylnaphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (manufactured by Nippon Acetate / Poval), VF-17, polymerization degree 1700, (Saponification degree 98.0-99.0 mol%): 0.5 g + H ₂ O: 45.8 (g) mixed solution).

  A conductive polymer layer is formed by immersing an etched aluminum formed foil with a precoat layer formed in an electrolytic polymerization solution, using the external electrode brought into contact with the precoat layer as an anode, fixing the current value to 0.4 mA, and performing electrolytic polymerization. (Solid electrolyte layer) was formed.

  Next, a carbon paste and a silver paste were sequentially applied to the portion of the aluminum foil where the conductive polymer layer was formed and dried to complete a total of 20 capacitor elements.

  About these 20 capacitor | condenser elements, the equivalent series resistance (ESR) in 100 kHz was measured as an initial characteristic.

(Example 8)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, sodium alkylnaphthalene sulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (JM-33, manufactured by Nihon Acetate / Poval Co., Ltd., polyvinyl alcohol, polymerization degree) 3300, saponification degree 93.5 to 94.5 mol%): 0.5 g + H ₂ O: 45.8 (g) was used for electrolytic polymerization to form a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

Example 9
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, sodium butyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (manufactured by Nippon Vinegar Poval Co., Ltd., JM-05, polymerization degree 500, Ken The degree of conversion was 93.5 to 94.5 mol%): 0.5 g + H ₂ O: 45.8 (g), and electropolymerization was performed to form a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

(Example 10)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, sodium butyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (manufactured by Nippon Vinegar Poval Co., Ltd., JF-17, polymerization degree 1700, Ken degree _{98~99mol%): 0.5g + H 2} O: perform electrolytic polymerization using a mixture of 45.8 (g), thereby forming a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

(Example 11)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, sodium methyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + polyvinyl alcohol (manufactured by Nippon Vinegar Poval Co., Ltd., JMR-10HH, polymerization degree 240, Ken The degree of conversion was 99 mol%): 0.5 g + H ₂ O: 45.8 (g) was used for electrolytic polymerization to form a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

(Example 12)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, sodium methyl naphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + 4-nitrophenol 0.25 (g) + polyvinyl alcohol (Nippon Acetate, manufactured by Poval Co., Ltd.) , JMR-10HH, polymerization degree 240, saponification degree 99 mol%): 0.5 g + H ₂ O: 45.8 (g) was used for electrolytic polymerization to form a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

(Comparative Example 3)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, electrolytic polymerization is performed using a mixed solution of sodium alkylnaphthalene sulfonate: 0.4 (g) + pyrrole: 0.6 (g) + H ₂ O: 45.8 (g) as the electrolytic polymerization solution, and the conductive property. A polymer layer was formed. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

(Comparative Example 4)
Twenty capacitor elements were obtained in the same manner as in Example 7 except that the manufacturing method was changed to the following method. That is, a mixture of sodium alkylnaphthalenesulfonate: 0.4 (g) + pyrrole: 0.6 (g) + 4-nitrophenol: 0.25 (g) + H ₂ O: 45.8 (g) in the electrolytic polymerization solution Electrolytic polymerization was performed using the liquid to form a conductive polymer layer. The characteristic evaluation of the capacitor element was performed in the same manner as in Example 7.

  Table 2 shows the measurement results of the capacitor elements of Examples 7 to 12 and Comparative Examples 3 and 4.

  From Examples 7 to 12 and Comparative Examples 3 and 4, it was found that excellent ESR was obtained by containing polyvinyl alcohol.

  The electropolymerization liquid for forming a conductive polymer of the present invention is not only a solid electrolytic capacitor, but also an organic EL display, an organic transistor, a polymer battery, a solar battery, various sensor materials, an electromagnetic shielding material, an antistatic material, an electrochromic material, an artificial material. It can be suitably used for muscles and the like.

Sectional view of the solid electrolytic capacitor of the present invention

1 Valve metal 2 Dielectric oxide film 3 Preliminary conductive layer (A)
4 Conductive polymer layer containing polyvinyl alcohol (B)

Claims (11)

  In an electropolymerization liquid for forming a conductive polymer in which a conductive polymer monomer and a supporting electrolyte are dissolved in a solvent, alkylnaphthalenesulfonic acid or a salt thereof as a supporting electrolyte and polyvinyl alcohol as an additive An electropolymerization liquid for forming a conductive polymer.   The electropolymerization liquid for forming a conductive polymer according to claim 1, wherein the conductive polymer monomer is pyrrole.   The electropolymerization liquid for forming a conductive polymer according to claim 1 or 2, wherein the solvent of the electropolymerization liquid for forming a conductive polymer is water. 4. The electropolymerization liquid for forming a conductive polymer according to claim 1, wherein at least one compound represented by the following general formulas (1) to (3) is dissolved as an additive. .

(In the formulas (1) to (3), R represents a hydrogen atom, a nitro group, a hydroxyl group, a linear or branched alkyl group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different. , At least one represents a nitro group, and at least one represents a hydroxyl group.)   In the formation of the conductive polymer layer on the valve action metal on which the dielectric oxide film is formed, the conductive polymer layer in the electropolymerization liquid for forming a conductive polymer according to any one of claims 1 to 4. The manufacturing method of the solid electrolytic capacitor which has the process of forming by electropolymerization.   In the formation of the conductive polymer layer on the valve action metal on which the dielectric oxide film is formed, the step of forming the preliminary conductive layer (A), and the preliminary conductive layer (A) according to claim 1 A method for producing a solid electrolytic capacitor comprising: forming a conductive polymer layer (B) by electrolytic polymerization in the electropolymerization liquid for forming a conductive polymer according to any one of the above.   The method for producing a solid electrolytic capacitor according to claim 6, wherein the preliminary conductive layer (A) contains a manganese dioxide layer.   The preliminary conductive layer (A) contains a conductive polymer layer formed by applying a solution containing a solvent-soluble or solvent-dispersible conductive polymer and then drying the solution. The manufacturing method of the solid electrolytic capacitor of description.   The method for producing a solid electrolytic capacitor according to claim 6, wherein the preliminary conductive layer (A) contains a conductive polymer layer formed by chemical polymerization of a conductive polymer monomer. In a solid electrolytic capacitor having a conductive polymer layer on a dielectric oxide film on the surface of a valve metal,
A solid electrolytic capacitor, wherein the conductive polymer layer comprises a composite layer containing polyvinyl alcohol and a conductive polymer.   The solid electrolytic capacitor according to claim 10, obtained by the method for producing a solid electrolytic capacitor according to claim 5.

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