Dielectric layer self-repairing composition for solid electrolytic capacitor

Abstract

To provide a dielectric layer self-repairing composition for a solid electrolytic capacitor excellent in voltage resistance while maintaining film repairability for a long period of time.SOLUTION: The dielectric layer self-repairing composition for a solid electrolytic capacitor comprises a water-soluble compound (A) and an ionic liquid (C), wherein the melting point of the ionic liquid (C) is 100 °C or lower, and the water-soluble compound (A) is polyether polyol and / or poly (meth) acrylate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a self-repairing composition for a dielectric layer of a solid electrolytic capacitor. [Background technology]

[0002] The solid electrolyte layer of a solid capacitor is formed by chemical polymerization, electrolytic polymerization, or by using a liquid dispersion containing particles of a conductive polymer. In recent years, with the increase in data processing volume, solid electrolytic capacitors are required to maintain a high level of withstand voltage, and efforts have been made to improve the repairability of the oxide film on the surface of tantalum sintered compacts, which form the dielectric layer. For example, Patent Document 1 discloses a technique in which an ionic liquid is impregnated into a tantalum sintered body having a conductive polymer formed on the surface thereof. Patent Document 2 discloses a technique that uses a liquid dispersion containing conductive polymer particles, an ionic liquid, and polyvinyl alcohol, a water-soluble polymer. However, the long-term film repairability is insufficient and there is room for improvement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-9569 [Patent Document 2] International Publication No. 2023 / 189924 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a self-repairing composition for a dielectric layer of a solid electrolytic capacitor that maintains film repairability for a long period of time and has excellent voltage resistance.

[0005] The present inventors have conducted extensive research to solve these problems and have arrived at the present invention. That is, the present invention provides a self-repairing composition for a dielectric layer for a solid electrolytic capacitor, which comprises a water-soluble compound (A) and an ionic liquid (C), wherein the melting point of the ionic liquid (C) is 100°C or less and the water-soluble compound (A) is a polyether polyol and / or a poly(meth)acrylate; and an electrolyte layer for a solid electrolytic capacitor, which comprises a solid electrolyte layer containing a π-conjugated polymer compound (B), and the self-repairing composition impregnated into the solid electrolyte layer. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a self-repairing composition for a dielectric layer for a solid electrolytic capacitor that maintains film repairability for a long period of time and has excellent voltage resistance. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present invention will be described in detail below.

[0008] <Self-repairing composition for dielectric layers of solid electrolytic capacitors> The self-repairing composition for a dielectric layer for a solid electrolytic capacitor of the present invention is a self-repairing composition for a dielectric layer for a solid electrolytic capacitor comprising a water-soluble compound (A) and an ionic liquid (C), wherein the melting point of the ionic liquid (C) is 100°C or less, and the water-soluble compound (A) is a polyether polyol and / or a poly(meth)acrylate.

[0009] <Water-soluble compound (A)> The water-soluble compound (A) will be explained below. In the present invention, a water-soluble compound refers to a compound that dissolves in an amount of 1 g or more in 100 g of water at 25° C., and the water-soluble compound (A) is a polyether polyol and / or poly(meth)acrylate that satisfies the above. In the present invention, "(meth)acrylate" means "acrylate and / or methacrylate," and "(meth)acrylic" means "acrylic and / or methacrylic." Examples of polyether polyols include polyalkylene glycols, polyoxyalkylene adducts of polyhydric alcohols, and polyoxyalkylene block polymers. Examples of poly(meth)acrylates include carboxyl group-containing polymers, hydroxyl group-containing polymers, and amide group-containing polymers. Furthermore, examples of the polyalkylene glycols, polyoxyalkylene adducts of polyhydric alcohols, polyoxyalkylene block polymers, carboxyl group-containing polymers, hydroxyl group-containing polymers, and amide group-containing polymers include polyethylene glycol, polypropylene glycol, poly(meth)acrylic acid, poly(meth)acrylic acid-2-ethylhexyl(meth)acrylate copolymers, sodium poly(meth)acrylate, 2-hydroxyethyl poly(meth)acrylate, polyoxyethylene polyoxypropylene polyoxyethylene block polymers, polyoxyethylene adducts of polyhydric alcohols, polyoxypropylene adducts of polyhydric alcohols, polyoxyethylene polyoxypropylene adducts of polyhydric alcohols (such as glycerin polyoxyethylene polyoxypropylene adducts), and polyacrylamide. The polyethylene glycol may be, for example, a polyethylene glycol represented by the general formula H(OCH2-CH2) n Examples of such polyethylene glycols include OH polyethylene glycols, which are commercially available and are manufactured by Sanyo Chemical Industries, Ltd. under the trade names PEG-600, PEG-4000S, PEG-6000S, PEG-10000, and PEG-20000.

[0010] Of the above water-soluble compounds (A), from the viewpoint of long-term film repairability, preferred are polyalkylene glycols, polyoxyalkylene adducts of polyhydric alcohols, polyoxyalkylene block polymers, carboxyl group-containing polymers, and hydroxyl group-containing polymers, and more preferred are polyethylene glycols, polyacrylic acid-2-ethylhexyl acrylate copolymers, poly2-hydroxyethyl acrylate, polyoxyethylene polyoxypropylene polyoxyethylene block polymers, and glycerin polyoxyethylene polyoxypropylene adducts.

[0011] The number average molecular weight of the water-soluble compound (A) is preferably 100 to 50,000 from the viewpoints of crystallization and solubility in water.

[0012] The number average molecular weight (Mn) and weight average molecular weight (Mw) in the present invention can be measured using gel permeation chromatography (GPC) under the following conditions.

[0013] Measurement conditions for polyether polyol Equipment (example): Tosoh Corporation HLC-8120 Column (example): TSKgel G2500PWXL (two columns) [manufactured by Tosoh Corporation] Measurement temperature: 40℃ Sample solution: water / methanol (volume ratio 8 / 2) Solution injection volume: 100μl Detector: Refractive index detector Standard substance: 12 standard polyethylene glycols (EASiVial PEG) manufactured by Tosoh Corporation (weight average molecular weight: 106, 194, 282, 400, 600, 1000, 1500, 4000, 7000, 13000, 20000, 30000)

[0014] Measurement conditions for poly(meth)acrylate Device (example): Tosoh Corporation HLC-8120 Column (example): TSK GEL GMH6 (two columns) [manufactured by Tosoh Corporation] Measurement temperature: 40℃ Sample solution: 0.25 wt% THF solution Solution injection volume: 100μl Detector: Refractive index detector Reference material: 12 standard polystyrenes (TSKstandard POLYSTYRENE) manufactured by Tosoh Corporation (weight average molecular weight: 500, 1050, 2800, 5970, 9100, 18100, 37900, 96400, 190000, 355000, 1090000, 2890000)

[0015] <Ionic Liquid (C)> The ionic liquid (C) will be explained below. The ionic liquid (C) of the present invention is not particularly limited as long as it has a melting point of 100° C. or less, and is preferably an ionic liquid having a melting point of 70° C. or less. The ionic liquid of the present invention is a salt composed of an anion component and a cation component.

[0016] The anion components that make up the ionic liquid (C) include halogen ions (F - , Cl - , Br - and I - etc.), carboxylate anions {mono- or dicarboxylic acids having 1 to 8 carbon atoms (formic acid, acetic acid, propionic acid, oxalic acid, succinic acid, phthalic acid, etc. (-COO - )}, sulfonate ions {ions of sulfonic acids having 1 to 20 carbon atoms (methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, etc. (-SO3 - )}, sulfate ester ion {ions of compounds containing sulfate ester groups with carbon atoms of 1 to 10 ((-OSO3 - ))}, phosphate ion {phosphate ion or ion of a compound containing a phosphate group having 1 to 10 carbon atoms (-PO3 2- )}, phosphate ester ions {ions of compounds containing a phosphate ester group having 1 to 10 carbon atoms (ions of monobutyl phosphate, diethyl phosphate, dibutyl phosphate, etc.)}, thiocyanate ions, perchlorate ions, sulfate ions, nitrate ions, BF4 - , PF6 - , SbF6 - , AsF6 - , TlF6 - , BF3Cl - , PF5Cl - , SbF5Cl - , AsF5Cl - , TlF5Cl - , BF3Br - , PF5Br - , SbF5Br - , AsF5Br - , TlF5Br -, BF3I - , PF5I - , SbF5I - , AsF5I - and TlF5I - ; and other anions, e.g., OH - , ClO4 - etc. Of the above anion components, from the viewpoint of film repairability, sulfonate ions, sulfate ions, sulfate ester ions, and phosphate ester ions are preferred, and methanesulfonate ions, sulfate ions, ethyl sulfate ions, and diethyl phosphate ions are more preferred.

[0017] Examples of the cationic component constituting the ionic liquid (C) include ammonium cations, pyridinium cations, and amidinium cations.

[0018] Examples of ammonium cations include aliphatic quaternary ammonium having an alkyl and / or alkenyl group having 4 to 30 or more carbon atoms (tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, trimethylethylammonium, tetraethylammonium, trimethylpropylammonium, dimethyldipropylammonium, ethylmethyldipropylammonium, butyltrimethylammonium, dimethyldibutylammonium, tetrabutylammonium, tetrahexylammonium, trimethyldecylammonium, and dimethyldidecylammonium), aromatic quaternary ammonium having 6 to 30 or more carbon atoms (trimethylphenylammonium, dimethylethylphenylammonium, and triethylphenylammonium), and alicyclic quaternary ammonium having 3 to 30 or more carbon atoms (N,N-dimethylpyrrolidinium, N-ethyl-N-methylpyrrolidinium, N,N-diethylpyrrolidinium, N,N-dimethylmorpholinium, N-ethyl-N-methylmorpholinium, N,N-diethylmorpholinium, N,N-dimethylpiperidinium, and N,N-diethylpiperidinium).

[0019] Examples of pyridinium cations include 3-methyl-1-propylpyridinium, 1-propyl-3-methylpyridinium, 1-butyl-3-methylpyridinium, 1-butyl-4-methylpyridinium, 1-butyl-3,4-dimethylpyridinium, and 1-butyl-3,5-dimethylpyridinium.

[0020] Examples of the amidinium cation include an imidazolinium cation, an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

[0021] Examples of the imidazolinium cation include 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethylimidazolinium, 1,3-dimethyl-2,4-diethylimidazolinium, 1,2-dimethyl-3,4-diethylimidazolinium, 1-methyl-2,3,4-triethylimidazolinium, 1,2,3,4-tetraethylimidazolinium, 1,2,3-trimethylimidazolinium, 1,3-dimethyl-2-ethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, 1,2,3-triethylimidazolinium, 4-cyano-1,2,3-trimethylimidazolinium, 3-cyanomethyl-1,2-dimethylimidazolinium, 2-cyanomethyl-1,3- Examples of suitable imidazolinium compounds include dimethylimidazolinium, 4-acetyl-1,2,3-trimethylimidazolinium, 3-acetylmethyl-1,2-dimethylimidazolinium, 4-methylcarboxymethyl-1,2,3-trimethylimidazolinium, 3-methylcarboxymethyl-1,2-dimethylimidazolinium, 4-methoxy-1,2,3-trimethylimidazolinium, 3-methoxymethyl-1,2-dimethylimidazolinium, 4-formyl-1,2,3-trimethylimidazolinium, 3-formylmethyl-1,2-dimethylimidazolinium, 3-hydroxyethyl-1,2-dimethylimidazolinium, 4-hydroxymethyl-1,2,3-trimethylimidazolinium, and 2-hydroxyethyl-1,3-dimethylimidazolinium.

[0022] Examples of imidazolium cations include 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetramethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1,2-dimethyl-3-ethylimidazolium, 1,2,3-triethylimidazolium, 1,2,3,4-tetraethylimidazolium, 1,3-dimethyl-2-phenylimidazolium, 1,3-dimethyl-2-benzylimidazolium, 1-benzyl-2,3-dimethylimidazolium, 4-cyano-1,2,3-trimethylimidazolium, 3-cyanomethyl-1,2-dimethylimidazolium, and the like. imidazolium, 2-cyanomethyl-1,3-dimethyl-imidazolium, 4-acetyl-1,2,3-trimethylimidazolium, 3-acetylmethyl-1,2-dimethylimidazolium, 4-methylcarboxymethyl-1,2,3-trimethylimidazolium, 3-methylcarboxymethyl-1,2-dimethylimidazolium, 4-methoxy-1,2,3-trimethylimidazolium, 3-methoxymethyl-1,2-dimethylimidazolium, 4-formyl-1,2,3-trimethylimidazolium, 3-formylmethyl-1,2-dimethylimidazolium, 3-hydroxyethyl-1,2-dimethylimidazolium, 4-hydroxymethyl-1,2,3-trimethylimidazolium, and 2-hydroxyethyl-1,3-dimethylimidazolium.

[0023] Examples of the tetrahydropyrimidinium cation include 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,8-diazabicyclo[5,4,0]-7-undecenium, and 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium. Indecenium, 1,5-diazabicyclo[4,3,0]-5-nonenium, 5-methyl-1,5-diazabicyclo[4,3,0]-5-nonenium, 4-cyano-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-cyanomethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 2-cyanomethyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 4-acetyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium 3-acetylmethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 4-methylcarboxymethyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-methylcarboxymethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 4-methoxy-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-methoxymethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium tetrahydropyrimidinium, 4-formyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 3-formylmethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 3-hydroxyethyl-1,2-dimethyl-1,4,5,6-tetrahydropyrimidinium, 4-hydroxymethyl-1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, and 2-hydroxyethyl-1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium.

[0024] Examples of dihydropyrimidinium cations include 1,3-dimethyl-1,4- or -1,6-dihydropyrimidinium (these are referred to as 1,3-dimethyl-1,4(6)-dihydropyrimidinium, and the same notation will be used hereinafter), 1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, 1,2,3,4-tetramethyl-1,4(6)-dihydropyrimidinium, 1,2,3,5-tetramethyl-1,4(6)-dihydropyrimidinium, 8-methyl-1,8-diazabicyclo[5,4,0]-7,9(10)-undecadienium, 5-methyl-1,5-diazabicyclo[4,3,0]-5,7(8)-nonadienium, 4 -Cyano-1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, 3-cyanomethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium, 2-cyanomethyl-1,3-dimethyl-1,4(6)-dihydropyrimidinium, 4-acetyl-1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, 3-acetylmethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium , 4-methylcarboxymethyl-1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, 3-methylcarboxymethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium, 4-methoxy-1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, 3-methoxymethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium, 4-formyl-1,2,3-trimethyl- Examples include 1,4(6)-dihydropyrimidinium, 3-formylmethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium, 3-hydroxyethyl-1,2-dimethyl-1,4(6)-dihydropyrimidinium, 4-hydroxymethyl-1,2,3-trimethyl-1,4(6)-dihydropyrimidinium, and 2-hydroxyethyl-1,3-dimethyl-1,4(6)-hydropyrimidinium.

[0025] Of the above cationic components, from the viewpoint of film repairability, amidinium cations are preferred, imidazolium cations are more preferred, and 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium are even more preferred.

[0026] In the self-repairing composition for a dielectric layer for a solid electrolytic capacitor of the present invention, the content of the water-soluble compound (A) is preferably 5 to 20% by weight based on the weight of the self-repairing composition from the viewpoint of conductivity.

[0027] The content of the ionic liquid (C) is preferably 2 to 50% by weight based on the weight of the self-repairing composition, from the viewpoint of film repairability.

[0028] The weight ratio of the water-soluble compound (A) to the ionic liquid (C) [(A) / (C)] is preferably 0.1 to 10 from the viewpoint of long-term film repairability.

[0029] <Electrolyte layer for solid electrolytic capacitors> The electrolyte layer for a solid electrolytic capacitor of the present invention is an electrolyte layer comprising a solid electrolyte layer containing a π-conjugated polymer compound (B) and the above-mentioned self-repairing composition impregnated into the solid electrolyte layer.

[0030] <π-conjugated polymer compound (B)> The π-conjugated polymer compound (B) will be explained below. The π-conjugated polymer compound (B) is a polymer compound that has a π-conjugated structure in the main chain and exhibits electron conduction type conductivity, and examples of polythiophene derivatives (polythiophene and substituted polythiophene), polyaniline derivatives (polyaniline and substituted polyaniline), polypyrrole derivatives (polypyrrole and substituted polypyrrole), polyacetylene derivatives (polyacetylene and substituted polyacetylene), and polyisothianaphthene derivatives (polyisothianaphthene and substituted polyisothianaphthene) can be used. Of the π-conjugated polymer compounds (B), polythiophene derivatives are preferred, and substituted polythiophenes are more preferred, from the viewpoints of electrical conductivity and solder reflow resistance.

[0031] The π-conjugated polymer compound (B) can be obtained by polymerizing raw material monomers, which can be carried out by known methods such as anionic polymerization or oxidative polymerization.

[0032] Examples of raw material monomers for the π-conjugated polymer compound include compounds having a thiophene skeleton, a pyrrole skeleton, and an aniline skeleton, which may be used alone or in combination of two or more. Examples of compounds having a thiophene skeleton include 3-alkyl group-substituted thiophenes such as 3-n-hexylthiophene and 3-n-dodecylthiophene, 3-alkoxy group-substituted thiophenes such as 3-methoxythiophene and 3-heptyloxythiophene, 3,4-dialkoxy-substituted thiophenes such as 3,4-ethylenedioxythiophene, 3-polyether group-substituted thiophenes such as 3-(1,3-dioxopentyl)thiophene and 3-(1,4,7,10-tetraoxaundecyl)thiophene, and alkylsulfonic acid group-substituted thiophenes such as 3-(3-thienyl)-propane-1-sulfonic acid, 4-(3-thienyl)-butane-1-sulfonic acid, and 6-(3-thienyl)-hexane-1-sulfonic acid. Examples of compounds having a pyrrole skeleton include 3-alkyl group-substituted pyrroles such as 3-n-hexylpyrrole and 3-n-dodecylpyrrole, 3-alkoxy group-substituted pyrroles such as 3-methoxypyrrole and 3-heptyloxypyrrole, 3-polyether group-substituted pyrroles such as 3-(1,3-dioxopentyl)pyrrole and 3-(1,4,7,10-tetraoxaundecyl)pyrrole, and alkylsulfonic acid group-substituted pyrroles such as 3-(3-pyrrolyl)-propane-1-sulfonic acid, 4-(3-pyrrolyl)-butane-1-sulfonic acid, and 6-(3-pyrrolyl)-hexane-1-sulfonic acid. Examples of compounds having an aniline skeleton include sulfonate group-substituted anilines such as o-, m-, or p-aminobenzenesulfonic acid, aniline-2,6-disulfonic acid, and methylaminobenzenesulfonic acid, and carboxy group-substituted anilines such as o-, m-, or p-aminobenzenecarboxylic acid, aniline-2,6-dicarboxylic acid, and methylaminobenzenecarboxylic acid. Of the above raw material monomers, from the viewpoint of electrical conductivity and solder reflow resistance, preferred are compounds having a thiophene skeleton, more preferred are 3,4-dialkoxy-substituted thiophenes, and even more preferred is 3,4-ethylenedioxythiophene.

[0033] The π-conjugated polymer compound (B) may contain a dopant (anion, polymer anion, etc.) as needed. Examples of anions include sulfate ions, nitrate ions, phosphate ions, sulfonate ions, and carboxylate ions. Examples of dopants that generate sulfonate ions include p-toluenesulfonic acid and naphthalenesulfonic acid. Examples of polymer anions include polymeric polysulfonic acids. Specific examples of polymer anions include polyvinylsulfonic acid, polystyrenesulfonic acid (PSS (including copolymers and substituted derivatives thereof)), polyallylsulfonic acid, polyacrylicsulfonic acid, polymethacrylicsulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, polyestersulfonic acids (such as aromatic polyestersulfonic acids), and phenolsulfonic acid novolac resins.

[0034] Among the above-mentioned π-conjugated polymer compounds (B), from the viewpoints of electrical conductivity and solder reflow resistance, a polyion complex of a polythiophene derivative and a polymer anion is preferred, and a polyion complex of poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) is more preferred.

[0035] The polyion complex of poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) can be synthesized by known methods, such as dissolving 3,4-ethylenedioxythiophene and poly(styrenesulfonate) in water and polymerizing the 3,4-ethylenedioxythiophene with an oxidizing agent under stirring to obtain an aqueous dispersion of the polyion complex of poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate).

[0036] The electrolyte layer for a solid electrolytic capacitor can be obtained, for example, by forming a layer of a π-conjugated polymer compound (B) on an anode and impregnating the layer with a mixture of a water-soluble compound (A) and an ionic liquid (C).

[0037] The method for forming a layer of the π-conjugated polymer compound (B) on the anode is not limited, and examples thereof include a method of immersing the anode in an aqueous dispersion of the π-conjugated polymer compound and drying it.

[0038] The method for impregnating the mixture of the water-soluble compound (A) and the ionic liquid (C) is not limited, but examples thereof include a method of immersing an anode having a layer of the π-conjugated polymer compound (B) formed thereon in a self-repairing composition containing the water-soluble compound (A), the ionic liquid (C), and water, and then drying it.

[0039] When a solvent is contained in the layer formed using the self-repairing composition and the π-conjugated polymer compound of the present invention, it is necessary to remove the solvent. In the case of a solvent with a low boiling point, the solvent can be removed by natural drying at room temperature or by heat drying using circulating air, but in the case of a solvent with a high boiling point, heat drying using a reduced pressure dryer is preferred.

[0040] To obtain a layer with sufficient strength and conductivity, the heat treatment temperature is preferably 50 to 190°C, and more preferably 80 to 170°C to obtain a layer with high conductivity.

[0041] From the viewpoint of electrical conductivity, the thickness of the electrolyte layer formed on the substrate surface is preferably 0.05 to 100 μm, and more preferably 0.1 to 50 μm. If the coating is made thicker than 0.05 μm, sufficient electrical conductivity can be obtained. Furthermore, if the thickness is 100 μm or less, cracking and peeling are less likely to occur during formation.

[0042] The layer formed from the self-repairing composition of the present invention and the π-conjugated polymer compound can be used as an electrolyte layer of a solid electrolytic capacitor. The solid electrolytic capacitor is not particularly limited, and examples thereof include aluminum electrolytic capacitors (wound aluminum electrolytic capacitors, stacked aluminum electrolytic capacitors, etc.), tantalum electrolytic capacitors, and niobium electrolytic capacitors. [Example]

[0043] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" below refer to parts by weight.

[0044] <Production Example 1> A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube was charged with 30 parts of toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 8.3 parts (116 mmol) of acrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 5.8 parts (50 mmol) of 2-hydroxyethyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and heated to 80°C with stirring. A solution of 0.9 parts of azobisisobutyronitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in 5 parts of toluene was added dropwise over 3 hours. After the dropwise addition, the mixture was heated with stirring for an additional 3 hours while maintaining the temperature at 80°C. The toluene was then distilled off by heating to 100°C under a reduced pressure of 0.5 kPa, yielding Mn5400 polyacrylic acid 2-hydroxyethyl acrylate copolymer as water-soluble compound (A-3).

[0045] <Production Example 2> A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube was charged with 100 parts of ethyl acetate as a solvent and heated to 78°C. Next, under solvent reflux, while blowing nitrogen into the reaction vessel, a monomer blend solution having the following composition and an initiator solution having the following composition were continuously added dropwise to the reaction vessel using a dropping funnel over a period of 5 hours to allow radical polymerization to proceed in the reaction vessel, and then the mixture was dried to obtain Mn11000 polyacrylic acid 2-ethylhexyl acrylate copolymer as water-soluble compound (A-4).

[0046] Composition of the monomer mixture: 90 parts of acrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 10 parts of 2-ethylhexyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0047] Initiator solution: 2.2 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.] and 17.8 parts of ethyl acetate [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.]

[0048] <Production Example 3> A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube was charged with 92 parts (1.0 mol) of glycerin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 1.1 parts (0.02 mol) of potassium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and reacted with 704 parts (16 mol) of ethylene oxide (manufactured by Sigma-Aldrich Co., Ltd.) at 170°C until pressure equilibrium was reached. Subsequently, a mixture of 2,200 parts (50 mol) of ethylene oxide (manufactured by Sigma-Aldrich Co., Ltd.) and 472 parts (8 mol) of propylene oxide (manufactured by Sigma-Aldrich Co., Ltd.) homogenized in a bomb was reacted, and the reaction was terminated when pressure equilibrium was reached. Then, to remove potassium hydroxide, Kyoward 600 and Kyoward 700 (Kyowa Chemical Industry Co., Ltd.) were used as adsorbents to reduce the potassium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) to less than 1 ppm, thereby obtaining Mn3460 glycerin polyoxyethylene polyoxypropylene adduct as water-soluble compound (A-6).

[0049] <Production Example 4> The same procedure as in Production Example 1 was carried out except that the amount of azobisisobutyronitrile was changed from 0.9 parts by weight to 0.15 parts by weight, and a polyacrylic acid 2-hydroxyethyl acrylate copolymer with an Mn of 45,000 was obtained as a water-soluble compound (A-7).

[0050] Example 1 20 parts of 1-ethyl-3-methylimidazolium methanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) as ionic liquid (C-1), 20 parts of Mn600 polyethylene glycol (PEG-600, manufactured by Sanyo Chemical Industries, Ltd.) as water-soluble compound (A-1), and water were added to a total of 100 parts and stirred for 1 hour to prepare a self-healing composition of the present invention.

[0051] <Anode> Step (1) Using a 50,000 CV / g element equipped with an anode lead and using tantalum as the valve metal, a voltage of 20 V was applied for 24 hours in a 60°C aqueous phosphoric acid solution [85 wt% aqueous phosphoric acid solution, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.] to perform a chemical conversion treatment, forming a dielectric oxide film and obtaining a tantalum sintered body.

[0052] Step (2): The tantalum sintered body was immersed in an aqueous dispersion of poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (Sigma-Aldrich high conductivity coating type dispersion concentration: 1.5 wt%) for 10 minutes, and then dried at 120°C for 30 minutes to obtain a tantalum sintered body having a solid electrolyte layer of poly(3,4-ethylenedioxythiophene) as the π-conjugated polymer compound (B).

[0053] Step (3): The tantalum sintered body having the solid electrolytic layer formed thereon was immersed in a self-repairing composition under reduced pressure for 10 minutes, and then dried at 150°C for 30 minutes to prepare an anode having an electrolytic layer according to the present invention.

[0054] <Capacitor> Graphite paste (manufactured by Sigma-Aldrich), silver paste (manufactured by Sigma-Aldrich), and copper foil (electrolytic copper foil, AS ONE) were applied to the anode obtained in step (3), which was then dried. The anode was then aged at 6.3 V and 105°C for 1 hour to create a capacitor.

[0055] <Example 2> An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with Mn6000 polyethylene glycol [PEG-6000S, manufactured by Sanyo Chemical Industries, Ltd.] as the water-soluble compound (A-2).

[0056] Example 3 An anode and a capacitor having the self-healing composition of the present invention and an electrolyte layer were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with the water-soluble compound (A-3), which was the Mn5400 polyacrylic acid 2-hydroxyethyl acrylate copolymer described in Production Example 1.

[0057] Example 4 An anode and a capacitor having the self-healing composition of the present invention and an electrolyte layer were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with the water-soluble compound (A-4), which was the Mn11000 polyacrylic acid 2-ethylhexyl acrylate copolymer described in Preparation Example 2.

[0058] <Example 5> An anode and a capacitor having the self-healing composition of the present invention and an electrolyte layer were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with a water-soluble compound (A-5), which was an Mn8000 polyoxyethylene polyoxypropylene polyoxyethylene block polymer (Newpol PE68, manufactured by Sanyo Chemical Industries, Ltd.).

[0059] Example 6 An anode and a capacitor having the self-repairing composition of the present invention and an electrolyte layer were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with the water-soluble compound (A-6), which was the Mn3460 glycerin polyoxyethylene polyoxypropylene adduct described in Preparation Example 3.

[0060] Example 7 An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the ionic liquid (C-1) in Example 1 was replaced with 1-butyl-3-methylimidazolium hydrogen sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the ionic liquid (C-2).

[0061] Example 8 An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the ionic liquid (C-1) in Example 1 was replaced with 1-ethyl-3-methylimidazolium ethyl sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the ionic liquid (C-3).

[0062] Example 9 An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the ionic liquid (C-1) in Example 1 was replaced with 1-ethyl-2,3-dimethylimidazolium ethyl sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the ionic liquid (C-4).

[0063] Example 10 An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the ionic liquid (C-1) in Example 1 was replaced with 1-ethyl-3-methylimidazolium diethyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the ionic liquid (C-5).

[0064] Example 11 An anode and a capacitor having the self-healing composition of the present invention and an electrolyte layer were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with the water-soluble compound (A-7), which was the Mn45000 polyacrylic acid 2-hydroxyethyl acrylate copolymer described in Production Example 4.

[0065] Example 12 An anode and a capacitor having a self-healing composition and an electrolyte layer of the present invention were prepared in the same manner as in Example 1, except that the water-soluble compound (A-1) in Example 1 was replaced with Mn200 polyethylene glycol [PEG-200, manufactured by Sanyo Chemical Industries, Ltd.] as the water-soluble compound (A-8).

[0066] Example 13 20 parts of 1-ethyl-3-methylimidazolium methanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) as ionic liquid (C-1), 2 parts of Mn600 polyethylene glycol (PEG-600, manufactured by Sanyo Chemical Industries, Ltd.) as water-soluble compound (A-1), and water were added to a total of 100 parts and stirred for 1 hour to prepare an anode and capacitor having the self-healing composition of the present invention and an electrolyte layer.

[0067] Example 14 Five parts of 1-ethyl-3-methylimidazolium methanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) as ionic liquid (C-1), 50 parts of Mn600 polyethylene glycol (PEG-600, manufactured by Sanyo Chemical Industries, Ltd.) as water-soluble compound (A-1), and water were added to a total of 100 parts and stirred for one hour to produce an anode and capacitor having the self-healing composition of the present invention and an electrolyte layer.

[0068] <Comparative Example 1> An anode and a capacitor having a self-repairing composition and an electrolyte layer were prepared in the same manner as in Example 7, except that the water-soluble compound (A-1) was not added.

[0069] <Comparative Example 2> An anode and a capacitor having a self-repairing composition and an electrolyte layer were prepared in the same manner as in Example 7, except that the water-soluble compound (A-1) was changed to Mw22000 polyvinyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0070] [Table 1]

[0071] The self-repairing compositions and anodes and capacitors having electrolyte layers obtained in Examples 1 to 14 and Comparative Examples 1 and 2 were evaluated by the following methods. The results are shown in Table 1.

[0072] <Voltage resistance test> The withstand voltage of the capacitors obtained in each example and comparative example was measured using a model "TR6143" manufactured by Advantest Corporation. The voltage was increased at a rate of 100 mV / sec and then maintained at 14 V for 1 second, and this process was repeated. The test was stopped when the current reached 100 mA or more, and the number of times the test was repeated at a current of less than 100 mA is shown in Table 1. The test was stopped after 10 repetitions.

[0073] In Comparative Examples 1 and 2, which do not contain water-soluble compound (A), when the process of increasing the voltage at a rate of 100 mV / sec and maintaining it at 14 V for 1 second was repeated three times or less, the current became 100 mA or more, and the withstand voltage was poor. In contrast, in each Example, even when the process of increasing the voltage at a rate of 100 mV / sec and maintaining it at 14 V for 1 second was repeated five to ten times, the current was less than 100 mA, and capacitors were obtained that maintained film repairability for a long period of time and showed good results in terms of withstand voltage. [Industrial Applicability]

[0074] The self-repairing composition of the present invention is useful as a solid electrolytic capacitor that is required to have long-term reliability and is used in data centers and the like.

Claims

1. A self-repairing composition for a dielectric layer for a solid electrolytic capacitor, comprising a water-soluble compound (A) and an ionic liquid (C), wherein the melting point of the ionic liquid (C) is 100°C or less, and the water-soluble compound (A) is a polyether polyol and / or a poly(meth)acrylate.

2. 2. The self-repairing composition for a dielectric layer for a solid electrolytic capacitor according to claim 1, wherein the water-soluble compound (A) has a number average molecular weight of 100 to 50,000.

3. 2. The self-repairing composition for a dielectric layer for a solid electrolytic capacitor according to claim 1, wherein the weight ratio [(A) / (C)] of the water-soluble compound (A) to the ionic liquid (C) is 0.1 to 10.

4. An electrolyte layer for a solid electrolytic capacitor, comprising: a solid electrolyte layer containing a π-conjugated polymer compound (B); and the self-repairing composition according to claim 1 impregnated into the solid electrolyte layer.

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