JP6462255B2 - Electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a conductive polymer, a specific diester, an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring, and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring. The present invention relates to an electrolytic capacitor including at least one aromatic compound selected from the group consisting of group compounds and a method for producing the same.

  Conductive polymers are used, for example, as electrolytes for aluminum electrolytic capacitors, tantalum electrolytic capacitors, niobium electrolytic capacitors and the like because of their high conductivity.

  As the conductive polymer in this application, for example, those obtained by chemical oxidative polymerization or electrolytic oxidative polymerization of thiophene or a derivative thereof are used.

  The organic sulfonic acid is mainly used as a dopant when performing chemical oxidative polymerization of the thiophene or a derivative thereof, and a transition metal is used as an oxidizing agent. Among them, ferric iron is said to be suitable. Usually, a ferric salt of an organic sulfonic acid is used as an oxidizing agent and a dopant in chemical oxidative polymerization of thiophene or a derivative thereof (Patent Documents 1 and 2).

  However, an electrolytic capacitor manufactured using a conductive polymer prepared using an organic sulfonic acid transition metal salt such as ferric organic sulfonate as an oxidant and dopant has a large leakage current, particularly in a high temperature atmosphere. There was a problem that the leakage current increased.

  For this reason, it has been proposed to use a non-transition metal as the oxidizing agent, but it has not been possible to sufficiently reduce the leakage current.

  Also, a specific phosphoric acid diester is added to the dispersion of the conductive polymer, and the dispersion of the conductive polymer is used to produce a solid electrolytic capacitor with reduced ESR and increased capacitance. Attempts have been made (Patent Document 3).

  However, the dispersion of the conductive polymer to which the above phosphoric acid diester is added increases the viscosity during storage, so that it is substantially effective for industrial use that requires little change in state during storage. Therefore, it cannot be applied to the production of electrolytic capacitors, and it is considered that further reduction in leakage current is necessary.

JP 2003-160647 A JP 2004-265927 A JP 2014-41888 A

  In view of the circumstances as described above, an object of the present invention is to provide an electrolytic capacitor with low leakage current and excellent heat resistance.

  In order to solve the above-mentioned problems, the present invention has been intensively studied, and the electrolytic capacitor is made of a conductive polymer, at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester, and an aromatic ring. At least one aromatic compound selected from the group consisting of an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the above and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring; Or a high boiling point organic solvent having a boiling point of 150 ° C. or higher or a high boiling point organic solvent having a boiling point of 150 ° C. or higher in an amount of 20% by mass or more and less than 100% by mass. The above-described problems are solved by adopting a configuration containing the containing liquid.

  That is, in the first invention of the present application, at least one diester selected from the group consisting of a conductive polymer, a phosphite diester and a phosphoric diester, and at least one hydroxyl group bonded to the constituent carbon of the aromatic ring. And an at least one aromatic compound selected from the group consisting of aromatic compounds having at least one nitro group bonded to carbon constituting the aromatic ring. .

  And the 2nd invention of this application contains the high boiling point organic solvent whose boiling point is 150 degreeC or more further in the said 1st invention, or the high boiling point organic solvent whose boiling point is 150 degreeC or more at 20 mass% or more and less than 100 mass%. The electrolytic capacitor is configured to contain a high-boiling organic solvent-containing liquid.

  That is, the second invention of the present application includes at least one diester selected from the group consisting of a conductive polymer, a phosphite diester and a phosphodiester, and at least one hydroxyl group bonded to the constituent carbon of the aromatic ring. At least one aromatic compound selected from the group consisting of an aromatic compound having an aromatic ring and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring, a high-boiling organic solvent having a boiling point of 150 ° C. or higher, or a boiling point And a high boiling point organic solvent-containing liquid containing a high boiling point organic solvent having a temperature of 150 ° C. or higher at 20% by mass or more and less than 100% by mass.

  Further, in the present application, in the first and second inventions described above, when at least one of a glycidyl compound or a silane compound is further added, in addition to the characteristics that the original leakage current is small and the heat resistance is excellent. An electrolytic capacitor having a high breakdown voltage (that is, excellent withstand voltage) can be provided.

  Further, in the present application, the method of manufacturing the electrolytic capacitor of the first invention and the method of manufacturing the electrolytic capacitor of the second invention are also objects of the invention.

  According to the present invention, it is possible to provide an electrolytic capacitor with low leakage current and excellent heat resistance.

  In carrying out the present invention, the conductive polymer is not particularly limited to a specific one. Therefore, in the present invention, at least selected from the group consisting of phosphite diesters and phosphodiesters, which are more characteristic. At least selected from the group consisting of one kind of diester, an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring, and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring One type of aromatic compound will be described first.

  The above diesters and aromatic compounds are used for the production of electrolytic capacitors in the form of a solution dissolved in a solvent.

  As the solvent, a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent-containing liquid containing 20% by mass or more and less than 100% by mass of a high-boiling organic solvent having a boiling point of 150 ° C. or higher is preferable. In this invention, it is an essential requirement to use this as a solvent.

  The at least one diester selected from the group consisting of the above phosphorous acid diester and phosphoric acid diester comprises phosphoric acid or an acid group of phosphoric acid, an alkyl group having 1 to 18 carbon atoms, a benzyl group, and a phenyl group Those composed of at least one group selected from the group are preferred. And as said alkyl group, a C1-C12 thing is more preferable, and a C1-C8 thing is further more preferable. Further, regarding a benzyl group or a phenyl group, an alkyl group may be bonded to the constituent carbon of the aromatic ring.

  Specifically, examples of the at least one ester selected from the group consisting of the phosphorous acid diester and the phosphoric acid diester include dimethyl phosphite, diethyl phosphite, dipropyl phosphite, diisopropyl phosphite, Dibutyl phosphite, diisobutyl phosphite, ditert-butyl phosphite, diamyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, diethylhexyl phosphite, didecyl phosphite, phosphorus phosphite Dilauryl acid, didotesyl phosphite, dimyristyl phosphite, dipalmethyl phosphite, distearyl phosphite, dibenzyl phosphite, diphenyl phosphite, dihexylphenyl phosphite, dimethyl phosphate, diethyl phosphate, phosphoric acid Dipropyl, diisopropyl phosphate, dibutyl phosphate, diisobuty phosphate , Diterylbutyl phosphate, diamyl phosphate, dihexyl phosphate, diheptyl phosphate, dioctyl phosphate, diethylhexyl phosphate, didecyl phosphate, dilauryl phosphate, dimyristyl phosphate, dipalmethyl phosphate, distearyl phosphate, Dibenzyl phosphate, diphenyl phosphate and the like are preferable.

  In the present invention, as the constituent material of the electrolytic capacitor, at least one ester selected from the group consisting of such phosphite diesters and phosphoric acid diesters is used as a group consisting of these phosphite diesters and phosphoric acid diesters. This is because at least one diester selected from the group reduces the leakage current of the electrolytic capacitor and improves the heat resistance, and contributes to providing an electrolytic capacitor having a low leakage current and excellent heat resistance. .

  As the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring, any of benzene, naphthalene, and anthracene can be used. Specific examples thereof include, for example, hydroxybenzoic acid (that is, hydroxybenzenecarboxylic acid), methyl hydroxybenzoate, ethyl hydroxybenzoate, propyl hydroxybenzoate, isopropyl hydroxybenzoate, butyl hydroxybenzoate, isobutyl hydroxybenzoate, Alkyl hydroxyalkyl alkyls having 1 to 8 carbon atoms such as tertiary butyl hydroxybenzoate, amyl hydroxybenzoate, hexyl hydroxybenzoate, heptyl hydroxybenzoate, octyl hydroxybenzoate, ethylhexyl hydroxybenzoate, etc., nitrophenol , Dinitrophenol, trinitrophenol, aminonitrophenol, methoxyphenol, eugenol (ie 4-anil-2-methoxyphenol), hydride Quinones (ie 1,4-dioxybenzene), hydroxyanisole, hydroxydinitrobenzene, dihydroxydinitrobenzene, alkylhydroxyanisole, hydroxynitroanisole, hydroxynitrobenzenecarboxylic acid (ie hydroxynitrobenzoic acid), dihydroxynitrobenzenecarboxylic acid ( In other words, dihydroxynitrobenzoic acid), phenol, dihydroxybenzene, trihydroxybenzene, dihydroxybenzenecarboxylic acid, trihydroxybenzenecarboxylic acid, hydroxybenzenedicarboxylic acid, dihydroxybenzenedicarboxylic acid, hydroxytoluenecarboxylic acid and other benzenes, nitro Naphthol, aminonaphthol, dinitronaphthol, hydroxynaphthoic acid (ie hydro Naphthalene-based compounds such as sinaphthalenecarboxylic acid), dihydroquinaphthalenecarboxylic acid, trihydroxynaphthalenecarboxylic acid, hydroxynaphthalenedicarboxylic acid, dihydroxynaphthalenedicarboxylic acid, hydroxyanthracene, dihydroxyanthracene, trihydroxyanthracene, tetrahydroxyanthracene, hydroxyanthracene Anthracene-based compounds such as carboxylic acid, hydroxyanthracene dicarboxylic acid, dihydroxyanthracene dicarboxylic acid and tetrahydroxyanthracenedione can be used. And these can each be used independently and can also use 2 or more types together.

  Of the aromatic compounds having at least one hydroxyl group bonded to the carbon constituting the aromatic ring, aromatic compounds having at least one carboxyl group are particularly preferred, and in particular, aromatic compounds having at least one carboxyl group and a nitro group. It is preferable to use in combination with an aromatic compound having at least one. And when this aromatic compound having at least one carboxyl group and an aromatic compound having at least one nitro group are used in combination, ESR of the electrolytic capacitor can be further reduced, and heat resistance and charge / discharge characteristics can be further improved. It is preferable because it is possible. And when using together the aromatic compound which has at least 1 or more of this carboxyl group, and the aromatic compound which has at least 1 or more nitro group, as a ratio of both, at least 1 carboxyl group is by mass ratio. Aromatic compound having at least one aromatic compound having at least one nitro group is preferably 1000: 1 to 1: 100, particularly preferably 50: 1 to 1: 1.

  Specific examples of the aromatic compound having at least one hydroxyl group and at least one carboxyl group as described above include hydroxybenzoic acid (that is, hydroxybenzenecarboxylic acid), methyl hydroxybenzoate, Ethyl hydroxybenzoate, propyl hydroxybenzoate, isopropyl hydroxybenzoate, butyl hydroxybenzoate, isobutyl hydroxybenzoate, tertiary butyl hydroxybenzoate, amyl hydroxybenzoate, hexyl hydroxybenzoate, heptyl hydroxybenzoate, hydroxybenzoic acid Octyl, ethylhexyl hydroxybenzoate, dihydroxybenzenecarboxylic acid, hydroxybenzenedicarboxylic acid, dihydroxybenzenedicarboxylic acid, aminohydroxybenzenecarbo Acid, hydroxytoluenecarboxylic acid, hydroxynitrobenzenecarboxylic acid (ie, hydroxynitrobenzoic acid), dihydroxynitrobenzenecarboxylic acid (ie, dihydroxynitrobenzoic acid), hydroxynaphthalenecarboxylic acid, acetylaminohydroxynaphthalenecarboxylic acid, hydroxyanthracenecarboxylic acid, etc. Hydroxybenzenecarboxylic acid, dihydroxybenzenecarboxylic acid, hydroxytoluenecarboxylic acid, hydroxynitrobenzenecarboxylic acid, hydroxynaphthalenecarboxylic acid, hydroxyanthracenecarboxylic acid and the like are preferable.

  Specific examples of the aromatic compound having at least one hydroxyl group and at least one nitro group as described above include, for example, nitrophenol, dinitrophenol, trinitrophenol, and hydroxydinitrobenzene as described above. , Dihydroxydinitrobenzene, hydroxynitroanisole, aminonitrophenol, hydroxynitrobenzene carboxylic acid (ie hydroxynitrobenzoic acid), dihydroxynitrobenzene carboxylic acid (ie dihydroxynitrobenzoic acid), nitronaphthol, dinitronaphthol, etc. Phenol, aminonitrophenol, hydroxynitrobenzenecarboxylic acid (that is, hydroxynitrobenzoic acid), nitronaphthol and the like are preferable.

  As described above, the aromatic having at least one nitro group used in combination with the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring and having at least the carboxyl group bonded to the constituent carbon of the aromatic ring As described above, the compound includes an aromatic ring other than an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring and at least one nitro group bonded to the constituent carbon of the aromatic ring. As long as it has a nitro group that binds to a constituent carbon, it does not have a hydroxyl group that binds to a constituent carbon of an aromatic ring, but it has the same hydroxyl group that binds to a constituent carbon of an aromatic ring as described above. In addition, an electrolytic capacitor having a low ESR, excellent heat resistance, and excellent charge / discharge characteristics can be obtained.

  Examples of the aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring and not having the hydroxyl group bonded to the constituent carbon of the aromatic ring include, for example, nitrobenzoic acid, nitroanisole, Nitrotoluene, dinitrotoluene, nitrobenzene, dinitrobenzene, trinitrobenzene, nitrobenzenecarboxylic acid, nitrobenzenedicarboxylic acid, nitrobenzenecarboxylic acid ester, nitrobenzenedicarboxylic acid ester, nitroanisolecarboxylic acid, nitronaphthalene, nitronaphthoic acid and the like can be used. Of course, an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring and not having a hydroxyl group bonded to the constituent carbon of the aromatic ring can be used alone, or 2 More than one type can be used in combination.

  In the above description, the case where the aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring is used in combination with the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring has been described. However, the aromatic compound having at least one nitro group bonded to carbon constituting the aromatic ring can be used alone. And the aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring is also a benzene-based one, like the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring, Either a naphthalene type or an anthracene type can be used.

  In the present invention, in the construction of the electrolytic capacitor, the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring as described above and the aromatic having at least one nitro group bonded to the constituent carbon of the aromatic ring The reason why at least one aromatic compound selected from the group consisting of compounds is used is that these aromatic compounds together with at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester are electrolytic capacitors This is because it contributes to the reduction of the leakage current of the conductive polymer and has the ability to assist the electronic conduction of the conductive polymer, and the deterioration of the conductive polymer can be suppressed by the antioxidant action of the aromatic compound. It is.

  Examples of the high-boiling organic solvent having a boiling point of 150 ° C. or higher as described above include γ-butyrolactone (boiling point: 203 ° C.), butanediol (boiling point: 230 ° C.), dimethyl sulfoxide (boiling point: 189 ° C.), sulfolane. (Boiling point: 285 ° C.), N-methylpyrrolidone (boiling point: 202 ° C.), dimethyl sulfolane (boiling point: 233 ° C.), ethylene glycol (boiling point: 198 ° C.), diethylene glycol (boiling point: 244 ° C.), polyethylene glycol, etc. These can be used alone, or two or more of them can be used in combination. Polyethylene glycol may have no boiling point under normal pressure, such as polyethylene glycol 600 and polyethylene glycol 1500 (the number after polyethylene glycol represents molecular weight), but any polyethylene glycol may be used. In the present invention, this polyethylene glycol is also included in the category of high-boiling organic solvents having a boiling point of 150 ° C. or higher.

  Further, the solvent used for preparing the high-boiling organic solvent-containing liquid containing the high-boiling organic solvent having a boiling point of 150 ° C. or higher at 20% by mass or more and less than 100% by mass is not particularly limited. C1-C4 lower alcohols such as ethanol, methanol, propanol, and butanol, water, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, and the like can be used, and methanol, ethanol, propanol, butanol, water, and the like are particularly preferable.

  In the high-boiling organic solvent-containing liquid, the content of the high-boiling organic solvent having a boiling point of 150 ° C. or higher is set to 20% by mass or more when the content of the high-boiling organic solvent is less than 20% by mass. This is because the ESR cannot be lowered sufficiently.

  In the present invention, an aromatic compound having at least one hydroxyl group bonded to at least one diester selected from the group consisting of the above-mentioned phosphite diester and phosphodiester and a constituent carbon of the aromatic ring and a constituent carbon of the aromatic ring When using as a solvent a solution in which at least one aromatic compound selected from the group consisting of aromatic compounds having at least one nitro group bonded to is dissolved in a solvent, the boiling point is 150 ° C. or higher. It is preferable to use an organic solvent or a high-boiling organic solvent-containing liquid containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher at 20% by mass or more and less than 100% by mass. When the solvent-containing liquid swells the previously formed conductive polymer and dries it, the conductive polymer rearranges It occurs allowed, and a conductive polymer layer in a more dense structure, such as by Teimetsu the ESR, is considered to contribute to improving the characteristics of the electrolytic capacitor.

  The reason for this is that the electrolytic capacitor does not contain the high-boiling organic solvent or the high-boiling organic solvent-containing liquid in the electrolytic capacitor as in the first invention of the present application, but as in the second invention, For those containing the above high-boiling organic solvents and liquids containing high-boiling organic solvents, first, by including such high-boiling organic solvents in the electrolytic capacitor, the ESR of the electrolytic capacitor is lowered and the capacitance is improved. In addition to reducing leakage current and having a high boiling point, it suppresses the internal pressure of the electrolytic capacitor from rising due to heating during soldering when manufacturing the electrolytic capacitor, and in the long term This is because the deterioration of the capacitor characteristics due to the volatilization of the liquid component from the inside can be suppressed. When the high boiling point organic solvent or the high boiling point organic solvent-containing liquid is used alone, the internal pressure of the electrolytic capacitor is increased by heating during soldering as described above. This is more preferable because it is possible to more effectively suppress the deterioration of the capacitor characteristics due to the volatilization of the liquid component from the electrolytic capacitor.

  In the present invention, at least one diester selected from the group consisting of the phosphorous acid diester and phosphoric acid diester is a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent having a boiling point of 150 ° C. or higher is 20 masses. In the case of preparing a solution with a high boiling point organic solvent-containing liquid or the like that is contained in an amount of not less than 100% and less than 100% by mass, the concentration is preferably 0.1 to 20% by mass. When the concentration of at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester is lower than the above, at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester If the concentration of at least one ester selected from the group consisting of phosphite diester and phosphodiester is higher than the above, the effect of reducing the leakage current due to ESR may not be sufficiently exhibited. This is because there is a risk of increasing the heat resistance or decreasing the heat resistance.

  The concentration of at least one diester selected from the group consisting of the phosphorous acid diester and the phosphoric acid diester is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, within the above range. Moreover, 15 mass% or less is more preferable, and 8 mass% or less is further more preferable.

  And at least one aromatic selected from the group consisting of an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring. In making the group compound into a solution with a high boiling point organic solvent having a boiling point of 150 ° C. or higher or a high boiling point organic solvent containing a high boiling point organic solvent having a boiling point of 150 ° C. or higher at 20% by mass to less than 100% by mass, etc. As a density | concentration of the said aromatic compound, 0.1-30 mass% is preferable. This is because if the concentration of the aromatic compound is lower than the above, the effect of reducing the leakage current may not be sufficiently exhibited, and if the concentration of the aromatic compound is higher than the above, the ESR is It is because there exists a possibility of making it increase or reducing heat resistance.

  At least one aromatic selected from the group consisting of an aromatic compound having at least one hydroxyl group bonded to carbon constituting the aromatic ring and an aromatic compound having at least one nitro group bonded to carbon constituting the aromatic ring Within the above range, the concentration of the compound is more preferably 0.2% by mass or more, further preferably 0.5% by mass or more, more preferably 20% by mass or less, and further preferably 15% by mass or less. And like 2nd invention of this application, the high boiling point organic solvent containing the high boiling point organic solvent whose boiling point is 150 degreeC or more or the high boiling point organic solvent whose boiling point is 150 degreeC or more is 20 mass% or more and less than 100 mass% In the case of constituting an electrolytic capacitor containing a liquid, it is preferable that the concentration of the aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring is slightly increased within the above range. As a density | concentration, 3 mass% or more is more preferable, 5 mass% or more is further more preferable, 20 mass% or less is more preferable, and 15 mass% or less is further more preferable.

  Further, the aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring has at least one hydroxyl group bonded to the constituent carbon of the aromatic ring and has at least a carboxyl group bonded to the constituent carbon of the aromatic ring. When used in combination with an aromatic compound having one, the aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring has a hydroxyl group bonded to the constituent carbon of the aromatic ring. Regardless, in the solution containing the diester or the like, it is preferably added so as to have a concentration of 0.05 to 20% by mass, and within the above range, the concentration is 0.2% by mass or more. It is more preferable to add so that it may become, It is more preferable to add so that it may become a density | concentration of 10 mass% or less.

  In the present application, in the second invention, the high-boiling organic solvent-containing liquid containing the high-boiling organic solvent having a boiling point of 150 ° C. or higher or the high-boiling organic solvent having a boiling point of 150 ° C. or higher in an amount of 20% by mass or more and less than 100% by mass. Is an essential requirement, and in the first invention, the reason for not being there is a difference in expected characteristics, but it is also derived from the electrolytic capacitor of the first invention and the method of manufacturing the electrolytic capacitor of the second invention. Yes.

  That is, the method for producing these electrolytic capacitors will be described in detail later, but both are selected from the group consisting of phosphorous diester and phosphoric diester after the formation of the conductive polymer layer on the capacitor element. 20 high-boiling organic solvents having a boiling point of 150 ° C. or higher or high-boiling organic solvents having a boiling point of 150 ° C. or higher of at least one ester and an aromatic compound having at least one hydroxyl group bonded to carbon constituting the aromatic ring It is common until it is impregnated with a solution dissolved in a high-boiling organic solvent-containing liquid that is contained in an amount of not less than 100% by mass and less than 100% by mass, but is then dried and the boiling point of the solvent is 150 ° C. or higher. Or a high-boiling organic solvent-containing liquid containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher at 20% by mass or more and less than 100% by mass. What is not provided is the electrolytic capacitor of the first invention, which is not dried after impregnation with the above solution, and has a high boiling point organic solvent having a boiling point of 150 ° C. or higher as a solvent or a high boiling point organic solvent having a boiling point of 150 ° C. or higher. The electrolytic capacitor of the second invention is such that a high-boiling organic solvent-containing liquid containing 20% by mass or more and less than 100% by mass of the solvent is contained in the electrolytic capacitor by being contained in the electrolytic capacitor.

  And a solution containing the above diester or the like (more precisely, at least one diester selected from the group consisting of phosphoric diesters and phosphoric diesters, and an aromatic having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring. A high-boiling organic solvent having a boiling point of 150 ° C. or higher, or a boiling point of 150 ° C., and at least one aromatic compound selected from the group consisting of compounds and aromatic compounds having at least one nitro group bonded to carbon constituting the aromatic ring When a solution containing at least one of a glycidyl compound and a silane compound is added to a solution containing a high-boiling organic solvent containing 20% by mass or more and less than 100% by mass of the above high-boiling organic solvent, It is preferable because the withstand voltage is improved and the breakdown voltage is increased.

  Examples of the glycidyl compound include polyethylene glycol diglycidyl ether, diethylene glycol glycidyl, glycidyl methacrylate, epoxy propanol (that is, glycidol), methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, and epoxy butane (that is, Glycidyl methane), epoxy pentane (ie glycidyl ethane), epoxy hexane (ie glycidyl propane), epoxy heptane (ie glycidyl butane), epoxy octane (ie glycidyl pentane), epoxy cyclohexene, ethylene glycol diglycidyl ether, propylene Glycol diglycidyl ether, butylene glycol diglycidyl ether Pentylene glycol diglycidyl ether, hexylene glycol diglycidyl ether, may be used such as glycerol diglycidyl ether.

  Examples of the silane compound include 3-glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, vinylsilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, butyltrisilane. Methoxysilane, 3-aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like can be used.

  And at least one aromatic selected from the group consisting of an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring. In dissolving a group compound in a high-boiling organic solvent-containing liquid containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent having a boiling point of 150 ° C. or higher at 20% by mass or more and less than 100% by mass, When added, the solubility of the aromatic compound is improved, and by adjusting the pH of the solution to about 3 to 7, corrosion of the dielectric layer of the capacitor element can be suppressed, which is preferable.

  Examples of the organic amine include methylamine, ethylamine, propylamine, butylamine, 3-ethoxypropylamine, hexylamine, octylamine, dodecylamine, 3-dimethylamino-1,2-propanediol, 2-amino- 2-hydroxymethyl-1,3-propanediol, 2-amino-1,3-propanediol, butyldiethanolamine, 3-aminopropyltrimethoxysilane, and the like can be used.

  In the present invention, thiophene or a derivative thereof, pyrrole or a derivative thereof, aniline or a derivative thereof, or the like is used as a monomer for synthesizing the conductive polymer, and thiophene or a derivative thereof is particularly preferable.

  Examples of the thiophene derivative in the thiophene or a derivative thereof include 3,4-ethylenedioxythiophene, 3-alkylthiophene, 3-alkoxythiophene, 3-alkyl-4-alkoxythiophene, 3,4-alkylthiophene, 3 , 4-alkoxythiophene, alkylated ethylenedioxythiophene obtained by modifying the above 3,4-ethylenedioxythiophene with an alkyl group, and the like. The alkyl group or alkoxy group preferably has 1 to 16 carbon atoms, 1-4 is especially preferable.

  The alkylated ethylenedioxythiophene obtained by modifying the 3,4-ethylenedioxythiophene with an alkyl group will be described in detail. The 3,4-ethylenedioxythiophene and the alkylated 3,4-ethylenedioxythiophene are as follows. It corresponds to the compound represented by the general formula (1).

（式中、Ｒは水素またはアルキル基である）

(Wherein R is hydrogen or an alkyl group)

  And the compound in which R in the general formula (1) is hydrogen is 3,4-ethylenedioxythiophene, which is expressed by the IUPAC name, “2,3-dihydro-thieno [3,4-b ] [1,4] dioxin (2,3-Dihydro-thieno [3,4-b] [1,4] dioxine) ", but this compound has a generic name rather than the IUPAC name. Since it is often expressed as “3,4-ethylenedioxythiophene”, in this document, “2,3-dihydro-thieno [3,4-b] [1,4] dioxin” is referred to as “3,4”. -"Ethylenedioxythiophene". And when R in the said General formula (1) is an alkyl group, as this alkyl group, a C1-C4 thing, ie, a methyl group, an ethyl group, a propyl group, a butyl group, is preferable, Specifically, a compound in which R in the general formula (1) is a methyl group is represented by IUPAC name, “2-methyl-2,3-dihydro-thieno [3,4-b] [1,4 Dioxin (2-Methyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxine) ”, which is hereinafter simplified and displayed as“ methylated ethylenedioxythiophene ”. To do. A compound in which R in the general formula (1) is an ethyl group is represented by IUPAC name, “2-ethyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2-Ethyl). -2,3-dihydro-thieno [3,4-b] [1,4] dioxine) ", hereinafter, this is simplified and expressed as" ethylated ethylenedioxythiophene ". A compound in which R in the general formula (1) is a propyl group is represented by “IUPAC name”, “2-propyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2-Propyl). -2,3-dihydro-thieno [3,4-b] [1,4] dioxine) ", hereinafter, this is simplified and expressed as" propylated ethylenedioxythiophene ". A compound in which R in the general formula (1) is a butyl group is represented by “IUPAC name”, “2-butyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2 -Butyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxine) ", hereinafter, this will be simplified and expressed as" butylated ethylenedioxythiophene ". Further, “2-alkyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin” is hereinafter simply expressed as “alkylated ethylenedioxythiophene”. Among these alkylated ethylenedioxythiophenes, methylated ethylenedioxythiophene, ethylated ethylenedioxythiophene, propylated ethylenedioxythiophene, and butylated ethylenedioxythiophene are preferable, and in particular ethylated ethylenedioxythiophene. Propylated ethylenedioxythiophene is preferred.

  These alkylated ethylenedioxythiophenes can be used alone or in combination of two or more. Furthermore, these alkylated ethylenedioxythiophenes and 3,4-ethylenedioxythiophenes can be used in combination.

  As the conductive polymer in the electrolytic capacitor of the present invention, either a conductive polymer dispersion or a conductive polymer obtained by polymerizing a monomer by so-called “in situ polymerization” can be used. it can.

  When the conductive polymer dispersion is used, various existing dopants can be used for the synthesis of the conductive polymer, and in particular, polystyrene sulfonic acid, sulfonated polyester, phenol sulfonic acid novolak resin, styrene. A polymer anion (polymer dopant) such as a copolymer of a sulfonic acid and a non-sulfonic acid monomer (which will be described in detail later) is preferred.

  The polystyrene sulfonic acid preferably has a weight average molecular weight of 10,000 to 1,000,000.

  That is, when the weight average molecular weight of the polystyrene sulfonic acid is smaller than 10,000, the conductivity of the obtained conductive polymer may be lowered. Moreover, when the weight average molecular weight of the said polystyrene sulfonic acid is larger than 1,000,000, there exists a possibility that the viscosity of the dispersion liquid of a conductive polymer may become high and it may become difficult to use in preparation of an electrolytic capacitor. The polystyrene sulfonic acid has a weight average molecular weight within the above range, preferably 20,000 or more, more preferably 40,000 or more, and preferably 800,000 or less. More preferable is 1,000 or less.

  The sulfonated polyester is a polycondensation product of dicarboxybenzenesulfonic acid diester such as sulfoisophthalic acid ester or sulfoterephthalic acid ester and alkylene glycol in the presence of a catalyst such as antimony oxide or zinc oxide. As the modified polyester, those having a weight average molecular weight of 5,000 to 300,000 are preferable.

  That is, when the weight average molecular weight of the sulfonated polyester is less than 5,000, the conductivity of the obtained conductive polymer may be lowered. Further, when the weight average molecular weight of the sulfonated polyester is larger than 300,000, the viscosity of the dispersion liquid of the conductive polymer is increased, which may make it difficult to use in the production of the electrolytic capacitor. The sulfonated polyester preferably has a weight average molecular weight within the above range of 10,000 or more, more preferably 20,000 or more, and preferably 100,000 or less. More preferable is 1,000 or less.

（式中のＲ^１は水素またはメチル基である）
で表される繰り返し単位を有するものが好ましく、このようなフェノールスルホン酸ノボラック樹脂としては、その重量平均分子量が５，０００〜５００，０００のものが好ましい。 Moreover, as said phenolsulfonic acid novolak resin, for example, the following general formula (2)

(Wherein R ¹ is hydrogen or a methyl group)
The phenolic sulfonic acid novolak resin having a weight average molecular weight of 5,000 to 500,000 is preferable.

  That is, when the weight average molecular weight of the phenolsulfonic acid novolak resin is smaller than 5,000, the conductivity of the obtained conductive polymer may be lowered. Moreover, when the weight average molecular weight of the said phenolsulfonic acid novolak resin is larger than 500,000, there exists a possibility that the viscosity of the dispersion liquid of a conductive polymer may become high, and it may become difficult to use in preparation of an electrolytic capacitor. The phenol sulfonic acid novolak resin preferably has a weight average molecular weight within the above range of 10,000 or more, more preferably 400,000 or less, and more preferably 80,000 or less. preferable.

  Next, the copolymer of the styrene sulfonic acid and the non-sulfonic acid monomer will be described. This copolymer is composed of styrene sulfonic acid, methacrylic acid ester, acrylic acid ester and unsaturated hydrocarbon-containing alkoxysilane compound. Or it is comprised with the copolymer with the at least 1 sort (s) of non-sulfonic-acid type monomer chosen from the group which consists of the hydrolyzate, exists in a conductive polymer as a polymer anion, and functions as a dopant.

  Copolymer of styrene sulfonic acid and at least one non-sulfonic acid monomer selected from the group consisting of methacrylic acid ester, acrylic acid ester and unsaturated hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof (hereinafter referred to as “non-sulfonic acid monomer”) In some cases, this may be referred to as “a copolymer of styrene sulfonic acid and a non-sulfonic acid monomer”). As a monomer copolymerized with styrene sulfonic acid, methacrylic acid ester, acrylic acid ester and unsaturated At least one selected from the group consisting of a hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof is used. Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and methacrylic acid. Acid hexyl Stearyl methacrylate, cyclohexyl methacrylate, diphenylbutyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, sodium sulfohexyl methacrylate, glycidyl methacrylate, methyl glycidyl methacrylate, hydroxyalkyl methacrylate, ie hydroxymethyl methacrylate , Hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxyhexyl methacrylate, hydroxy stearyl methacrylate, hydroxyalkyl methacrylate, hydroxypolyoxyethylene methacrylate, methoxyhydroxypropyl methacrylate, ethoxyhydroxypropyl methacrylate , Dihydroxypropyl methacrylate, Dihydroxybutyl tacrylate can be used, and hydroxyalkyl methacrylate having 1 to 4 carbon atoms in the alkyl group such as hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate is particularly preferable. It is preferable in view of characteristics as a dopant when copolymerized with an acid. In addition, those having a glycidyl group such as glycidyl methacrylate and methyl glycidyl methacrylate have a structure containing a hydroxyl group by ring opening of the glycidyl group. Like alkyl, it is preferable from the viewpoint of characteristics as a dopant when copolymerized with styrenesulfonic acid.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, stearyl acrylate, cyclohexyl acrylate, diphenylbutyl acrylate, dimethylaminoethyl acrylate, Acrylic acid such as diethylaminoethyl acrylate, sodium sulfohexyl acrylate, glycidyl acrylate, methyl glycidyl acrylate, hydroxyalkyl acrylate, ie hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate Hydroxyalkyl and the like can be used, but hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylic Acrylic acid hydroxyalkyl having a carbon number 1 to 4 alkyl groups such as hydroxyethyl butyl is preferred from the characteristics as a dopant when the copolymerised with styrene sulfonic acid. In addition, those having a glycidyl group such as glycidyl acrylate and methyl glycidyl acrylate have a structure containing a hydroxyl group by ring opening of the glycidyl group. Like alkyl, it is preferable from the viewpoint of characteristics as a dopant when copolymerized with styrenesulfonic acid.

  Examples of the unsaturated hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyldimethylmethoxysilane, 3- Methacryloxypropyldimethylethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxymethyldimethoxysilane, 3-acryloxymethyldiethoxysilane, 3-acryloxytriethoxysilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, p-styrylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxy Run, it can be used an unsaturated hydrocarbon containing alkoxysilane compound and a hydrolyzate thereof such as vinyl dimethyl methoxy silane. For example, when the unsaturated hydrocarbon-containing alkoxysilane compound is the above-mentioned 3-methacryloxypropyltrimethoxysilane, the hydrolyzate of the unsaturated hydrocarbon-containing alkoxysilane compound is converted into a hydroxyl group by hydrolysis of the methoxy group. The resulting structure becomes 3-methacryloxypropyltrihydroxysilane, or silanes condense to form an oligomer, resulting in a compound having a structure in which a methoxy group not used in the reaction is converted to a hydroxyl group . Examples of the unsaturated hydrocarbon-containing alkoxysilane compound include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryltrimethoxysilane, vinyltrimethoxysilane, and the like. It is preferable from the standpoint of properties as a dopant when copolymerized.

  Styrene in a copolymer of this styrene sulfonic acid and at least one non-sulfonic acid monomer selected from the group consisting of methacrylic acid esters, acrylic acid esters and unsaturated hydrocarbon-containing alkoxysilane compounds or hydrolysates thereof As a ratio of sulfonic acid and at least one non-sulfonic acid monomer selected from the group consisting of methacrylic acid ester, acrylic acid ester and unsaturated hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof, It is preferably 1: 0.01 to 0.1: 1.

  A copolymer of the styrene sulfonic acid and at least one non-sulfonic acid monomer selected from the group consisting of a methacrylic acid ester, an acrylic acid ester, an unsaturated hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof, The molecular weight is preferably about 5,000 to 500,000 in terms of weight average molecular weight from the viewpoint of water solubility and characteristics as a dopant, and more preferably about 40,000 to 200,000 in terms of weight average molecular weight.

  Polymer anions such as the above-mentioned polystyrene sulfonic acid, sulfonated polyester, phenol sulfonic acid novolak resin, copolymer of styrene sulfonic acid and non-sulfonic acid monomer can be used alone or in combination of two or more. It can also be used together.

  And thiophene using at least one polymer anion selected from the group consisting of the above polystyrene sulfonic acid, sulfonated polyester, phenol sulfonic acid novolak resin and a copolymer of styrene sulfonic acid and a non-sulfonic acid monomer, or the Oxidative polymerization of monomers such as derivatives is performed in water or an aqueous solution of water and a water-miscible solvent.

  Examples of the water-miscible solvent constituting the aqueous liquid include methanol, ethanol, propanol, acetone, acetonitrile, and the like. The mixing ratio of these water-miscible solvents with water is 50 in the entire aqueous liquid. The mass% or less is preferable.

  The conductive polymer can be obtained by oxidative polymerization of monomers. As the oxidative polymerization at that time, either chemical oxidative polymerization or electrolytic oxidative polymerization can be employed.

  The oxidizing agent used for conducting the chemical oxidative polymerization is not particularly limited, but a non-transition metal oxidizing agent is preferable. That is, in the present invention, it is used by at least one diester selected from the group consisting of phosphite diesters and phosphodiesters, and an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring. Even if the conducting polymer is synthesized using any oxidizing agent, the leakage current of the electrolytic capacitor can be reduced and the heat resistance can be improved. As for the oxidant, non-transition is possible because it does not contain a transition metal that increases the leakage current or decreases the heat resistance, and it is easier to reduce the leakage current and improve the heat resistance. Metal oxidizers are preferred

  As the non-transition metal oxidant as described above, for example, persulfate is used. Examples of the persulfate include ammonium persulfate, sodium persulfate, potassium persulfate, calcium persulfate, and barium persulfate.

  In chemical oxidative polymerization, the conditions during the polymerization are not particularly limited, but the temperature during chemical oxidative polymerization is preferably 5 ° C to 95 ° C, more preferably 10 ° C to 30 ° C, and polymerization is also performed. As time, 1 hour-72 hours are preferable, and 8 hours-24 hours are more preferable.

Electrolytic oxidation polymerization is be carried out even at a constant voltage at a constant current, for example, when performing electrolytic oxidation polymerization at a constant current, preferably 0.05mA ^/ cm ² ~10mA ^/ cm 2 as the current value, 0.2 mA / cm more preferably ^{2 ~4mA} / cm ^2, when performing electrolytic oxidation polymerization at a constant voltage, preferably 0.5V~10V as voltage, 1.5V to 5V is more preferable. The temperature during electrolytic oxidation polymerization is preferably 5 ° C to 95 ° C, and particularly preferably 10 ° C to 30 ° C. The polymerization time is preferably 1 hour to 72 hours, more preferably 8 hours to 24 hours. In the electrolytic oxidation polymerization, ferrous sulfate or ferric sulfate may be added as a catalyst.

  The conductive polymer obtained as described above is obtained immediately after polymerization in a state of being dispersed in water or an aqueous liquid, and includes persulfate as an oxidizing agent, iron sulfate used as a catalyst, and decomposition products thereof. Contains. Therefore, it is preferable to remove the metal component with a cation exchange resin after the impurities are dispersed by applying a dispersion of the conductive polymer containing the impurities to a dispersing machine such as an ultrasonic homogenizer, a high-pressure homogenizer, or a planetary ball mill. The particle size of the conductive polymer measured by the dynamic light scattering method at this time is preferably 100 μm or less, more preferably 10 μm or less, 0.01 μm or more, and more preferably 0.1 μm or more. After that, the ethanol precipitation method, ultrafiltration method, anion exchange resin, etc. are used to remove the oxidant and the catalyst generated by decomposition of the catalyst and, as will be described later, a conductivity improver and a binder are added as necessary. May be.

  As described above, the conductive polymer dispersion obtained as described above may contain a conductivity improver. Thus, when a conductive improver is contained in the conductive polymer dispersion, the conductivity of the conductive polymer film obtained by drying the conductive polymer dispersion is improved. Thus, ESR of an electrolytic capacitor using the conductive polymer as an electrolyte can be lowered.

  This is because, when an electrolytic capacitor is manufactured, when the capacitor element is immersed in a dispersion of a conductive polymer, taken out and dried, the layer density in the thickness direction of the conductive polymer is increased, thereby increasing the conductivity. It is considered that the interplanar spacing between molecules is narrowed, the conductivity of the conductive polymer is increased, and the ESR of the electrolytic capacitor is lowered when the conductive polymer is used as the electrolyte of the electrolytic capacitor.

  Examples of such a conductivity improver include high boiling points such as dimethyl sulfoxide, γ-butyrolactone, sulfolane, N-methylpyrrolidone, dimethyl sulfone, ethylene glycol, diethylene glycol, and polyethylene glycol (for example, high boiling point of 150 ° C. or higher). Organic solvents and saccharides such as erythritol, glucose, mannose, and pullulan, and dimethyl sulfoxide and butanediol are particularly preferable.

  The addition amount of such a conductivity improver is 5 to 3,000% on a mass basis with respect to the conductive polymer in the dispersion (that is, the conductivity improver with respect to 100 parts by mass of the conductive polymer). Is preferably 5 to 3,000 parts by mass), particularly preferably 20 to 700%. When the addition amount of the conductivity improver is less than the above, the effect of improving the conductivity is not sufficiently exhibited, and when the addition amount of the conductivity improver is more than the above, it takes time to dry the dispersion. Moreover, there is a possibility of causing a decrease in conductivity.

  The content of the conductive polymer in the dispersion affects the workability when the capacitor element is immersed in the conductive polymer dispersion and taken out, and is usually about 0.5 to 15% by mass. Is preferred. In other words, if the content of the conductive polymer is less than the above, it may take time to dry, and if the content of the conductive polymer is more than the above, the viscosity of the dispersion is high. Thus, workability in producing the electrolytic capacitor may be reduced.

  The conductive polymer obtained by drying the conductive polymer dispersion thus obtained has high conductivity and excellent heat resistance based on the properties of the polymer anion used as a dopant in the synthesis. Therefore, when it is used as an electrolyte, it becomes a factor for obtaining an electrolytic capacitor having low ESR and high reliability when used under high temperature conditions.

  In the production of an electrolytic capacitor, a capacitor element having at least one porous body of a valve metal selected from the group consisting of aluminum, tantalum and niobium and a dielectric layer made of an oxide film of the valve metal is used.

  The conductive polymer layer is formed on the capacitor element by impregnating the capacitor element with the conductive polymer dispersion and drying.

  The capacitor element is impregnated with the dispersion liquid of the conductive polymer by immersing the capacitor element in the dispersion liquid of the conductive polymer or by applying the dispersion liquid of the conductive polymer to the capacitor element by spraying or the like. Is called.

  Since the valve metal constituting the capacitor element is a porous body, the impregnated conductive polymer dispersion penetrates not only into the surface of the capacitor element but also into the inside of the valve metal porous body, In a capacitor element of a type using a separator, the capacitor element also enters the gap of the separator.

  Thereafter, the conductive polymer obtained by drying is used as an electrolyte. This conductive polymer is provided on the dielectric layer made of the oxide film of the valve metal on the surface of the valve metal that becomes the anode in the capacitor element. However, the conductive polymer may be attached to other parts of the capacitor element.

  At that time, it is preferable to add a binder to the dispersion of the conductive polymer in order to improve the adhesion between the conductive polymer and the dielectric layer of the capacitor element. Examples of such a binder include polyvinyl alcohol, polyurethane, polyester, acrylic resin, polyamide, polyimide, epoxy resin, polyacrylonitrile resin, polymethacrylonitrile resin, polystyrene resin, novolac resin, and silane coupling agent. In particular, polyester, polyurethane, acrylic resin and the like are preferable. Moreover, since the electroconductivity of a conductive polymer can be improved when the sulfone group is added like sulfonated polyallyl, sulfonated polyvinyl, and sulfonated polystyrene, it is more preferable.

  Then, the conductive polymer layer is formed on the capacitor element by repeating the impregnation and drying of the conductive polymer into the capacitor element as many times as necessary. When the impregnation of the conductive polymer is performed by immersing the capacitor element in the conductive polymer dispersion, it is necessary to remove the capacitor element from the conductive polymer dispersion prior to drying. is there.

  Alternatively, the conductive polymer layer may be formed on the capacitor element by so-called “in-situ polymerization”, which is performed during the manufacturing process of the electrolytic capacitor. However, even when the monomer is polymerized by this “in-situ polymerization”, the oxidizing agent is not particularly limited, but a non-transition metal oxidizing agent is preferably used.

  Examples of the non-transition metal oxidant used in the case of polymerizing monomers by such “in-situ polymerization” include, for example, a supercurrent such as a supersulfuric acid, an ammonium persulfate, a sodium persulfate, and a potassium supersulfate. Examples of dopants used in combination with acid salts, hydrogen peroxide, benzoyl peroxide, and the like include, for example, benzenesulfonic acid, benzenedisulfonic acid, toluenesulfonic acid, phenolsulfonic acid, nitrobenzenesulfonic acid, cresolsulfonic acid, Naphthalene disulfonic acid, naphthalene trisulfonic acid, naphthalene sulfonic acid, methyl naphthalene sulfonic acid, propyl naphthalene sulfonic acid, butyl naphthalene sulfonic acid, anthraquinone sulfonic acid, etc. are mentioned. Non-transition of Used in the state of Shokushio.

  When the electrolytic capacitor is manufactured as a wound electrolytic capacitor, as the capacitor element, for example, after etching the surface of a valve metal foil such as an aluminum foil, a chemical conversion treatment is performed to form an oxide film of the valve metal. A lead terminal is attached to the anode formed with the dielectric layer, and a lead terminal is attached to the cathode made of a valve metal foil such as an aluminum foil, and the anode with the lead terminal and the cathode are wound through a separator. The produced one is used. On the other hand, when the electrolytic capacitor is manufactured as a non-wound electrolytic capacitor such as a tantalum electrolytic capacitor, a niobium electrolytic capacitor, or a laminated aluminum electrolytic capacitor, as the capacitor element, for example, tantalum, niobium, aluminum, or the like serving as an anode In this case, in the case of a tantalum electrolytic capacitor, a tantalum sintered body is used as the tantalum porous body.

  And as mentioned above, after forming the layer of the conductive polymer that constitutes the electrolyte in the capacitor element, the capacitor is provided with at least one kind selected from the group consisting of phosphorous acid diester and phosphoric acid diester. At least one selected from the group consisting of a diester, an aromatic compound having at least one hydroxyl group bonded to the constituent carbon of the aromatic ring, and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring Impregnated with a high-boiling organic solvent containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher at 20% by mass to less than 100% by mass. By performing the operation to perform at least once, and then applying the necessary exterior, Capacitors are produced.

  Then, a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent having a boiling point of 150 ° C. or higher is obtained by impregnating a solution containing the diester or the like and then drying at least once. The electrolytic capacitor of the first invention of the present application is manufactured by preventing the liquid containing a high boiling point organic solvent containing 20% by mass or more and less than 100% by mass of the solvent from remaining in the electrolytic capacitor, and then applying a necessary exterior. Is done.

  The impregnation of the solution containing the diester or the like is performed by immersing the capacitor element after the formation of the conductive polymer layer in the solution or by applying a solution containing the diester or the like to the capacitor element by spraying or the like. Is called.

  In Patent Document 3, since the phosphoric acid diester is added to the dispersion of the conductive polymer, the viscosity increases during storage, making it difficult to produce an electrolytic capacitor. Since the diester and the conductive polymer are not allowed to coexist in the dispersion state, such a problem does not occur, and such a problem does not occur in the production of the electrolytic capacitor.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples illustrated in these examples. In the following examples and the like, “%” indicating the concentration of a solution, dispersion, etc. and “%” indicating purity are percentages based on mass unless otherwise specified.

  Prior to Examples, Preparation Examples A to D show preparation examples of conductive polymer dispersions A to D used for forming a conductive polymer layer constituting an electrolyte in Examples and the like. And the liquid used in manufacture of the electrolytic capacitor of an Example, ie, at least 1 type of diester chosen from the group which consists of phosphorous acid diester and phosphoric acid diester, and at least 1 hydroxyl group couple | bonded with the constituent carbon of an aromatic ring. At least one aromatic compound selected from the group consisting of an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring, and having a boiling point of 150 ° C. or higher as a solvent. A liquid using a high-boiling organic solvent-containing liquid containing a boiling-point organic solvent or a high-boiling organic solvent having a boiling point of 150 ° C. or higher in an amount of 20% by mass or more and less than 100% by mass (this liquid is used in the production of the electrolytic capacitor of the example. Since it is mainly used in the processing stage after the formation of the conductive polymer layer, in the following, it will be referred to as “processing liquid” Preparation example is if) shown in Preparation Example 1 to 26. In addition, the liquid used in the processing stage after the formation of the conductive polymer layer in the production of the electrolytic capacitor of the comparative example (this liquid is different in configuration from the processing liquid of the present invention, and is therefore referred to as “comparison processing liquid”). However, this "treatment liquid" includes both those that are dried and not contained in the electrolytic capacitor after use, and those that are not dried after use and become contained in the electrolytic capacitor. Preparation examples 27 to 32 are shown.

Preparation Example A of Conductive Polymer Dispersion
600 g of 4% aqueous solution of polystyrene sulfonic acid (manufactured by Teika Co., Ltd., weight average molecular weight 100,000) is put in a stainless steel container having an internal volume of 1 L, and 0.3 g of ferrous sulfate heptahydrate is added. 4 mL of ethylenedioxythiophene (that is, 3,4-ethylenedioxythiophene) was slowly added dropwise. Attach the anode to the above stainless steel container, and attach two stainless steel plates (3 cm wide x 3 cm long x 2 m thick) for the cathode in the solution, with a polytetrafluoroethylene stirring blade. The mixture was stirred and subjected to electrolytic oxidation polymerization at room temperature at a constant current of 1 mA / cm ² for 18 hours.

  After the electrolytic oxidation polymerization, it was diluted 6 times with water and then subjected to a dispersion treatment for 240 minutes with an ultrasonic homogenizer (Nippon Seiki Co., Ltd., US-T300). Thereafter, 100 g of Cation Exchange Resin Amberlite 120B (trade name) manufactured by Organo Corporation was added and stirred with a stirring blade for 1 hour. Subsequently, filter paper No. manufactured by Toyo Filter Paper Co., Ltd. The mixture was filtered through 131, and the treatment with this cation exchange resin and filtration were repeated three times to remove iron ions in the liquid. Thereafter, excess anions were removed by treatment with anion exchange resin and filtration.

  The solution after removal of the ionic component is passed through a filter having a pore size of 1 μm, and the passing solution is treated with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000) to release the free solution in the solution. Low molecular components were removed. After adding purified water to this solution to adjust the concentration of the content to 3%, the pH is adjusted to 3.81 by adding 2-amino-2-hydroxymethyl-1,3-propanediol. Water was added to adjust the concentration to 2.5% to obtain a conductive polymer dispersion A.

  When the particle size distribution of the conductive polymer in the obtained dispersion liquid A of conductive polymer was measured by ELS-Z manufactured by Otsuka Electronics, the average particle size was 130 nm.

Preparation example B of conductive polymer dispersion
1 L of pure water was added to a 2 L separable flask equipped with a stirrer, and 200 g of sodium styrenesulfonate and 5 g of hydroxyethyl acrylate were added thereto. And 1g of ammonium persulfate was added to the solution as an oxidizing agent, and the polymerization reaction of styrenesulfonic acid and hydroxyethyl acrylate was performed for 12 hours.

  Then, the reaction solution is treated with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius Co., Ltd., molecular weight fraction 50,000) to remove free low-molecular components in the solution to a concentration of 3%. By adjusting, a 3% aqueous solution of a copolymer of styrene sulfonic acid and hydroxyethyl acrylate was obtained.

  The obtained styrene sulfonic acid and hydroxyethyl acrylate copolymer had a weight average molecular weight of 150,000 estimated using a gel filtration column and dextran as a standard.

  All of the above except that a 3% aqueous solution of a copolymer of styrene sulfonic acid and hydroxyethyl acrylate was used in place of the 3% concentration polystyrene sulfonic acid aqueous solution in dispersion A of the conductive polymer. The same operation as in Preparation Example A of Conductive Polymer Dispersion A was performed to obtain a conductive polymer dispersion having a concentration of 3%. To the dispersion of the conductive polymer having a concentration of 3%, 3-dimethylamino-1,2-propanediol is added to adjust the pH to 3.00, and purified water is added to adjust the concentration to 2. The dispersion B of conductive polymer was adjusted to 5%.

  When the particle size distribution of the conductive polymer in dispersion B of this conductive polymer was measured with ELS-Z manufactured by Otsuka Electronics, the average particle size was 120 nm.

Preparation Example C of Conductive Polymer Dispersion
In place of ethylenedioxythiophene, methylated ethylenedioxythiophene is used, and in the final pH adjustment, in place of 3-dimethylamino-1,2-propanediol, 2-amino-1,3-propanediol is used, A conductive polymer dispersion C was obtained in the same manner as in Preparation Example B for conductive polymer dispersion except that the pH was adjusted to 2.97.

Preparation Example D of Conductive Polymer Dispersion
After 200 g of 3% aqueous solution of sulfonated polyester [Plus Coat Z-561 (trade name), weight average molecular weight 27,000, manufactured by Kyoyo Chemical Co., Ltd.] is placed in a 1 L container, 2 g of ammonium persulfate is added as an oxidizing agent. And dissolved by stirring with a stirrer. Then. 0.4 g of a 40% aqueous solution of ferric sulfate was added, and 3 mL of ethylenedioxythiophene was slowly dropped therein while stirring, and chemical oxidation polymerization of ethylenedioxythiophene was performed over 24 hours.

  100 g of Cation Exchange Resin Amberlite 120B (trade name) manufactured by Organo Corporation was added to the reaction solution after the above chemical oxidative polymerization, and stirred for 1 hour. Subsequently, filter paper No. manufactured by Toyo Filter Paper Co., Ltd. The mixture was filtered through 131, and the treatment with this cation exchange resin and filtration were repeated three times to remove all cation components such as iron ions in the liquid. The liquid was concentrated using an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000). The aqueous dispersion of the conductive polymer thus obtained had a dry solid content concentration measured at 105 ° C. of 3%. To 40 g of the 3% solution, 4 g of dimethyl sulfoxide (333% on a mass basis with respect to the conductive polymer) was added as a high boiling point solvent to obtain a conductive polymer dispersion.

  A copolymer of styrene sulfonic acid and hydroxyethyl acrylate prepared in Preparation Example B of a conductive polymer dispersion using a sulfonated polyester as a dopant and the conductive polymer dispersion thus obtained. The conductive polymer dispersion B having a dopant as a dopant is mixed at a mass ratio of 5: 1, and the co-polymerization of the conductive polymer having the sulfonated polyester as a dopant, styrenesulfonic acid, and hydroxyethyl acrylate. A mixed dispersion with a conductive polymer having the coalescence as a dopant was obtained as a conductive polymer dispersion D.

  Next, as described above, preparation examples of the “treatment liquid” used in the production of the electrolytic capacitor of the examples are shown in Preparation Examples 1 to 26, and “comparison treatment liquid” used in the production of the electrolytic capacitor of the comparative example. Are shown in Preparation Examples 27 to 32.

Preparation Example 1
To 100 g of ethylene glycol, 3 g of diethyl phosphite, 2 g of p-hydroxybenzoic acid and 1 g of nitrophenol were added and completely dissolved while stirring. 1 g of glycerol was added to the solution to prepare a treatment liquid of Preparation Example 1.

  The concentration of diethyl phosphite in the treatment solution of Preparation Example 1 was about 2.80%, the concentration of p-hydroxybenzoic acid was about 1.87%, and the concentration of nitrophenol was about 0.93%. Yes, the concentration of glycerol was about 0.93%.

Preparation Example 2
50 g of ethanol was added to 50 g of ethylene glycol, and further 3 g of diisopropyl phosphite and 3 g of p-hydroxybenzoic acid were added and completely dissolved while stirring. 1 g of glycerol was added to the solution to prepare a treatment liquid of Preparation Example 2.

  In the treatment solution of Preparation Example 2, the concentration of diisopropyl phosphite was about 2.80%, the concentration of p-hydroxybenzoic acid was about 2.80%, and the concentration of glycerol was about 0.93%. It was.

Preparation Example 3
After adding 50 g of distilled water to 50 g of ethylene glycol, and further adding 3 g of diethyl phosphite, 2 g of p-hydroxybenzoic acid, 1 g of nitrobenzoic acid, and 1 g of glycerol, N-butyl is stirred. Diethanolamine was added, the pH was adjusted to 3.5, and completely dissolved to prepare the treatment liquid of Preparation Example 3.

  In the treatment solution of Preparation Example 3, the concentration of diethyl phosphite is about 2.80%, the concentration of p-hydroxybenzoic acid is about 1.87%, and the concentration of nitrobenzoic acid is about 0.93%. The concentration of glycerol was also about 0.93%.

Preparation Example 4
A treatment solution of Preparation Example 4 was prepared in the same manner as in Preparation Example 1 except that ethylhexyl p-hydroxybenzoate was used instead of p-hydroxybenzoic acid.

  The concentration of diethyl phosphite in the treatment solution of Preparation Example 4 was about 2.80%, the concentration of ethylhexyl p-hydroxybenzoate was about 1.87%, and the concentration of nitrophenol was about 0.93%. The glycerol concentration was about 0.93%.

Preparation Example 5
A treatment solution of Preparation Example 5 was prepared in the same manner as in Preparation Example 1, except that dibutyl phosphate was used instead of diethyl phosphite.

  The concentration of dibutyl phosphate in the treatment of Preparation Example 5 is about 2.80%, the concentration of p-hydroxybenzoic acid is about 1.87%, the concentration of nitrophenol is about 0.93%, The concentration of glycerol was also about 0.93%.

Preparation Example 6
A treatment solution of Preparation Example 6 was prepared in the same manner as in Preparation Example 1, except that diethylhexyl phosphate was used instead of diethyl phosphite.

  The concentration of diethylhexyl phosphate in the treatment liquid of Preparation Example 6 is about 2.80%, and the concentrations of the other components are the same as in the treatment liquid of Preparation Example 1.

Preparation Example 7
A treatment solution of Preparation Example 7 was prepared in the same manner as in Preparation Example 1, except that dibenzyl phosphite was used instead of diethyl phosphite.

  The concentration of dibenzyl phosphite in the treatment liquid of Preparation Example 7 is about 2.80%, and the concentrations of the other components are the same as in the treatment liquid of Preparation Example 1.

Preparation Example 8
A treatment solution of Preparation Example 8 was prepared in the same manner as in Preparation Example 1, except that diphenyl phosphite was used instead of diethyl phosphite.

  The concentration of diphenyl phosphite in the treatment liquid of Preparation Example 8 is about 2.80%, and the concentrations of the other components are the same as in the treatment liquid of Preparation Example 1.

Preparation Example 9
A treatment solution of Preparation Example 9 was prepared in the same manner as in Preparation Example 1, except that dimethyl phosphate was used instead of diethyl phosphite, and methoxyphenol was used instead of hydroxybenzoic acid. .

  The concentration of dimethyl phosphate in the treatment solution of Preparation Example 9 is about 2.80%, the concentration of methoxyphenol is about 1.87%, the concentration of nitrophenol is about 0.93%, The concentration was also about 0.93.

Preparation Example 10
The treatment solution of Preparation Example 10 was carried out in the same manner as in Preparation Example 1, except that diethylhexyl phosphite was used instead of diethyl phosphite, and hydroxynaphthoic acid was used instead of hydroxybenzoic acid. Was prepared.

  The concentration of diethylhexyl phosphite in the treatment liquid of Preparation Example 10 is about 2.80%, the concentration of hydroxynaphthoic acid is about 1.87%, and the concentrations of other components are the treatment liquid of Preparation Example 1. It is the same as the case of.

Preparation Example 11
The treatment solution of Preparation Example 11 was carried out in the same manner as in Preparation Example 1, except that diisobutyl phosphite was used instead of diethyl phosphite, and methyl hydroxybenzoate was used instead of hydroxybenzoic acid. Was prepared.

  The concentration of diisobutyl phosphite in the treatment solution of Preparation Example 11 is about 2.80%, the concentration of methyl hydroxybenzoate is about 1.87%, and the concentrations of the other components are the treatment solution of Preparation Example 1. It is the same as the case of.

Preparation Example 12
The same procedure as in Preparation Example 1 except that diethylhexyl phosphite was used instead of diethyl phosphite, and eugenol (ie, 4-allyl-2-methoxyphenol) was used instead of hydroxybenzoic acid. To prepare a treatment liquid of Preparation Example 12.

  In the treatment liquid of Preparation Example 12, the concentration of diethylhexyl phosphite is about 2.8%, the concentration of eugenol is about 1.87%, and the concentrations of the other components are those of the treatment liquid of Preparation Example 1. It is the same.

Preparation Example 13
To 100 g of ethylene glycol, 3 g of diethyl phosphite, 10 g of p-hydroxybenzoic acid, 1 g of nitrobenzoic acid, and 1 g of glycerol were added, and then stirred, 2-amino-2-hydroxymethyl-1,3 -Propanediol was added, pH was adjusted to 5.0 (25 degreeC), and it was made to melt | dissolve completely, and the processing liquid of the preparation example 13 was prepared.

  The concentration of diethyl phosphite in the treatment solution of Preparation Example 13 was about 2.61%, the concentration of p-hydroxybenzoic acid was about 8.70%, and the concentration of nitrobenzoic acid was about 0.87%. The glycerol concentration was about 0.87%.

Preparation Example 14
A treatment solution of Preparation Example 14 was prepared in the same manner as in Preparation Example 13, except that 100 g of γ-butyrolactone was used instead of 100 g of ethylene glycol.

Preparation Example 15
A treatment solution of Preparation Example 15 was prepared in the same manner as in Preparation Example 13, except that 4 g of diisopropyl phosphite was added instead of 3 g of diethyl phosphite and 1 g of polysiloxane was further added.

  The concentration of diisopropyl phosphite in the treatment solution of Preparation Example 15 was about 3.42%, the concentration of polysiloxane was about 0.85%, and the concentration of p-hydroxybenzoic acid was about 8.55%. Yes, the concentration of nitrobenzoic acid was about 0.85% and the concentration of glycerol was also 0.85%.

Preparation Example 16
The same operation as in Preparation Example 13 was performed except that 2 g of dibutyl phosphate was added instead of 3 g of diethyl phosphite and 1 g of 3-glycidoxypropyltrimethoxysilane was further added. A treatment solution was prepared.

  The concentration of dibutyl phosphate in the treatment solution of Preparation Example 16 is about 1.74%, the concentration of 3-glycidoxypropyltrimethoxysilane is about 0.87%, and the concentrations of the other components are as in Preparation Example. This is the same as the case of the 13 treatment liquids.

Preparation Example 17
A treatment solution of Preparation Example 17 was prepared in the same manner as in Preparation Example 13, except that 3 g of diethylhexyl phosphate was added instead of 3 g of diethyl phosphite, and 1 g of polyethylene glycol 400 was further added. .

  The concentration of diethylhexyl phosphate in the treatment solution of Preparation Example 17 is about 2.59%, the concentration of polyethylene glycol 400 is about 0.86%, and the concentration of p-hydroxybenzoic acid is about 8.62%. The nitrobenzoic acid concentration was about 0.86% and the glycerol concentration was also about 0.86%.

Preparation Example 18
The same procedure as in Preparation Example 13 was carried out except that 7 g of diethyl phosphite was added instead of 3 g of diethyl phosphite and 10 g of phthalic acid was added instead of 10 g of p-hydroxybenzoic acid. 18 treatment liquids were prepared.

  In the treatment solution of Preparation Example 18, the concentration of diethyl phosphite is about 5.85%, the concentration of phthalic acid is about 8.40%, and the concentration of nitrobenzoic acid is about 0.84%. The concentration of glycerol was also about 0.84%.

Preparation Example 19
Instead of 3 g of diethyl phosphite, add 3 g of dibenzyl phosphite, add 1 g of nitrophenol instead of 1 g of nitrobenzoic acid, and replace with 2-amino-2-hydroxymethyl-1,3-propanediol Then, except that diethylamine was added and 1 g of polysiloxane was further added, the same operation as in Preparation Example 13 was performed to prepare a treatment liquid of Preparation Example 19.

  The concentration of dibenzyl phosphite in the treatment solution of Preparation Example 19 is about 2.59%, the concentration of nitrophenol is about 0.86%, the concentration of polysiloxane is about 0.86%, p -The concentration of hydroxybenzoic acid was about 8.62% and the concentration of glycerol was about 0.86%.

Preparation Example 20
All except that 3 g of diphenyl phosphite was added instead of 3 g of diethyl phosphite, 10 g of ethyl p-hydroxybenzoate was added instead of 10 g of p-hydroxybenzoic acid, and 1 g of polysiloxane was added. The same operation as in Preparation Example 13 was performed to prepare the treatment liquid of Preparation Example 20.

  The concentration of diphenyl phosphite in the treatment solution of Preparation Example 20 is about 2.59%, the concentration of ethyl p-hydroxybenzoate is about 8.62%, and the concentration of polysiloxane is about 0.86%. The glycerol concentration was 0.86%.

Preparation Example 21
All except that 2 g of dimethyl phosphite was used instead of 3 g of diethyl phosphite, 6 g of eugenol was used instead of 10 g of p-hydroxybenzoic acid, and 1 g of polyethylene glycol diglycidyl was used instead of 1 g of glycerol. The same operation as in Preparation Example 13 was performed to prepare the treatment liquid of Preparation Example 21.

  The concentration of dimethyl phosphite in the treatment solution of Preparation Example 21 was about 1.82%, the concentration of eugenol was 5.45%, the concentration of nitrobenzoic acid was about 0.91%, and polyethylene glycol The concentration of diglycidyl was also 0.91%.

Preparation Example 22
All preparation examples except that 4 g of diethylhexyl phosphite was used instead of diethyl phosphite, 8 g of hydroxynaphthoic acid was used instead of hydroxybenzoic acid, and 1 g of glycidyl modified polyester was used instead of 1 g of glycerol 13 was prepared in the same manner as in Preparation Example 22.

  The concentration of diphenyl phosphite in the treatment liquid of Preparation Example 22 was about 2.51%, the concentration of hydroxynaphthoic acid was about 7.01%, and the concentration of nitrobenzoic acid was about 0.88%. The concentration of the glycidyl-modified polyester was also about 0.88%.

Preparation Example 23
All preparation examples except that 5 g of diethyl phosphite was used instead of 3 g of diethyl phosphite, 6 g of hydroquinone was used instead of 10 g of hydroxybenzoic acid, 1 g of nitroanisole was used instead of 1 g of nitrobenzoic acid 13 was prepared in the same manner as in Preparation Example 23.

  In the treatment solution of Preparation Example 23, the concentration of diethyl phosphite is 4.42%, the concentration of hydroquinone is about 5.31%, the concentration of nitroanisole is about 0.88%, and the concentration of glycerol. Was about 0.88%.

Preparation Example 24
Instead of 3 g of diethyl phosphite, 4 g of diethylhexyl phosphite was used, 12 g of methoxyphenol was used instead of 10 g of hydroxybenzoic acid, 1 g of trimethylolpropane triglycidyl ether was used instead of 1 g of glycerol. All the same operations as in Preparation Example 13 were performed to prepare the treatment liquid of Preparation Example 24.

  The concentration of diethylhexyl phosphite in the treatment solution of Preparation Example 24 is about 3.39%, the concentration of methoxyphenol is about 10.17%, and the concentration of nitrobenzoic acid is about 0.85%. The concentration of trimethylolpropane triglycidyl ether was also about 0.85%.

Preparation Example 25
Preparation Example 13 except that 2 g of dihexylphenyl phosphite was used instead of 3 g of diethyl phosphite, 10 g of dinitrophenol was used instead of 10 g of hydroxybenzoic acid, and 1 g of erythritol was used instead of 1 g of glycerol The treatment liquid of Preparation Example 25 was prepared in the same manner as described above.

  The concentration of dihexyl phenyl phosphite in the treatment solution of Preparation Example 25 was about 1.75%, the concentration of dinitrophenol was about 8.77%, and the concentration of nitrobenzoic acid was about 0.88%. Yes, the concentration of erystol was about 0.88%.

Preparation Example 26
All except that 4 g of didodecyl phosphite was used instead of 3 g of diethyl phosphite, 15 g of ethyl hydroxybenzoate was used instead of 10 g of hydroxybenzoic acid, and 1 g of nitrotoluene was used instead of 1 g of nitrobenzoic acid. The same operation as in Preparation Example 13 was performed to prepare the treatment liquid of Preparation Example 26.

  The concentration of dodecyl phosphite in the treatment solution of Preparation Example 26 was about 3.31%, the concentration of ethyl p-hydroxybenzoate was about 12.40%, and the concentration of nitrotoluene was about 0.83%. The concentration of glycerol was about 0.83%.

Preparation Example 27 (for comparative example)
3 g of ammonium adipate was dissolved in 100 g of distilled water. The pH at that time was 6.2. 1 g of glycerol was added to the solution to prepare a comparative treatment solution of Preparation Example 27.

Preparation Example 28 (for comparative example)
3 g of dibutyl phosphate was added to 100 g of distilled water, and then dimethylamine was added with stirring to completely dissolve the dibutyl phosphate. The pH at that time was 5.2. 1 g of glycerol was added to the solution to prepare a comparative treatment solution of Preparation Example 28.

Preparation Example 29 (for comparative example)
3 g of hydroxybenzoic acid was added to 100 g of distilled water, and then dimethylamine was added with stirring to completely dissolve the hydroxybenzoic acid. The pH at that time was 5.8. 1 g of glycerol was added to the solution to prepare a comparative treatment solution of Preparation Example 29.

Preparation Example 30 (for comparative example)
10 g of ammonium adipate was dissolved in 100 g of ethylene glycol. The pH at that time was 6.2. 1 g of glycerol was added to the solution to prepare a comparative treatment solution of Preparation Example 30.

Preparation Example 31 (for Comparative Example)
3 g of dibutyl phosphate was added to 100 g of ethylene glycol, and then dimethylamine was added with stirring to completely dissolve the dibutyl phosphate. The pH at that time was 5.2. 1 g of glycerol was added to the solution, and 1 g of polyethylene glycol 400 was further added to prepare a comparative treatment solution.

Preparation Example 32 (for Comparative Example)
To 100 g of ethylene glycol, 8 g of hydroxybenzoic acid was added, and then dimethylamine was added with stirring to completely dissolve the hydroxybenzoic acid. The pH at that time was 5.8. 1 g of glycerol was added to the solution to prepare a comparative treatment solution of Preparation Example 32.

[Evaluation with a wound aluminum electrolytic capacitor (1)]
Example 1
In Example 1 and subsequent Examples 2 to 26, a wound aluminum electrolytic capacitor is manufactured and its characteristics are evaluated. First, production of the wound aluminum electrolytic capacitor of Example 1 will be described.

  The surface of the aluminum foil is made porous by etching, the etched aluminum foil is immersed in a 12% ammonium adipate aqueous solution, and a voltage of 70 V is applied to the aluminum foil in the ammonium adipate aqueous solution to form aluminum. A dielectric layer is formed on the surface of the foil to form an anode, a lead terminal is attached to the anode, a lead terminal is attached to a cathode made of aluminum foil, and the anode with the lead terminal and the cathode are wound via a separator. A capacitor element for producing a wound aluminum electrolytic capacitor having a set ESR of 30 mΩ or less, a set capacitance of 45 μF or more, a rated voltage of 35 V, and a set leakage current of 20 μA or less was produced.

  The capacitor element was immersed in the conductive polymer dispersion A prepared as described above (the conductive polymer in the conductive polymer dispersion A is polystyrene sulfonic acid as a dopant). After leaving for 5 minutes, it was taken out, dried at 180 ° C. for 30 minutes, then dipped again in conductive polymer dispersion A, taken out, and then dried at 180 ° C. for 30 minutes to form a conductive polymer layer. .

  Next, the capacitor element on which this conductive polymer layer was formed was immersed in the treatment solution of Preparation Example 1, and left for 1 minute, then taken out, dried at 180 ° C. for 30 minutes, and then packaged with an exterior material. The wound aluminum electrolytic capacitor of Example 1 was manufactured.

Examples 2 to 26
A capacitor element produced in the same manner as in Example 1 was immersed in a conductive polymer dispersion A, removed and dried in the same manner as in Example 1 to form a conductive polymer layer by repeating the operation twice. did.

  Prepare the required number of capacitor elements having conductive polymer layers formed as described above for use in the respective examples, and immerse these capacitor elements separately in the processing solutions of Preparation Examples 2 to 26, respectively. After leaving for 1 minute, it was taken out, dried at 180 ° C. for 30 minutes, and then packaged with an exterior material to produce a wound aluminum electrolytic capacitor of Examples 2 to 26.

Comparative Example 1
The capacitor element produced in the same manner as in Example 1 was dipped in the conductive polymer dispersion A, taken out, dried and dried twice in the same manner as in Example 1. A layer was formed.

  The capacitor element in which the conductive polymer layer is formed is used as it is (that is, at least one selected from the group consisting of dialkyl phosphite and dialkyl phosphate used in the present invention and a hydroxyl group bonded to the constituent carbon of the aromatic ring. An aromatic compound having at least one and a high-boiling organic solvent-containing liquid containing a high-boiling organic solvent having a boiling point of 150 ° C. or higher or a high-boiling organic solvent having a boiling point of 150 ° C. or higher in an amount of 20% by mass to less than 100% by mass. The wound aluminum electrolytic capacitor of Comparative Example 1 was manufactured by packaging with an exterior material (without being immersed in a treatment liquid or the like).

Comparative Examples 2-4
The capacitor element produced in the same manner as in Example 1 was dipped in the conductive polymer dispersion A, taken out, dried and dried twice in the same manner as in Example 1. A layer was formed.

  The required number of capacitor elements having the conductive polymer layer formed as described above are used in Comparative Examples 2 to 4, and these capacitor elements are used as the comparative treatment liquids of Preparation Examples 27 to 29, respectively. Each was immersed separately, allowed to stand for 1 minute, then taken out, dried at 180 ° C. for 30 minutes, and then packaged with an exterior material to produce wound aluminum electrolytic capacitors of Comparative Examples 2 to 4.

  Regarding the wound aluminum electrolytic capacitors of Examples 1 to 26 and Comparative Examples 1 to 4 manufactured as described above (hereinafter sometimes simply referred to as “capacitors”), ESR, capacitance, and leakage current Was measured. The results are shown in Tables 1 and 2 as initial characteristics together with the types of treatment liquids and comparative treatment liquids. In addition, about the kind of process liquid and the process liquid for a comparison, it shows with a preparation example number on the relationship on a space. And the measuring method of ESR, an electrostatic capacitance, and a leakage current is as follows.

ESR:
Using an LCR meter (4284A) manufactured by HEWLETT PACKARD, measurement is performed at 100 kHz under the condition of 25 ° C.
Capacitance:
Using an LCR meter (4284A) manufactured by HEWLETT PACKARD, measurement is performed at 120 Hz under the condition of 25 ° C.
Leak current:
After applying a rated voltage of 35 V to the capacitor at 25 ° C. for 60 seconds, the leakage current is measured with a digital oscilloscope.

  The above measurement is performed for each sample for 20 samples, and the numerical values shown in Tables 1 and 2 are obtained by calculating the average value of the 20 values and rounding off to the second decimal place.

  Moreover, the capacitor | condenser of Examples 1-26 after the said characteristic measurement and Comparative Examples 1-4 was stored in a 125 degreeC thermostatic bath in a stationary state for 3,000 hours, and after the storage, ESR, Capacitance and leakage current were measured. In addition, for those whose leakage current exceeded 500 μA during the storage period, it was assumed that a short circuit failure (short circuit occurrence failure) occurred. The results are shown in Tables 3 and 4. However, regarding short-circuit defects, the total number of capacitors used for measurement is displayed in the denominator, and the number of capacitors in which short-circuit defects have occurred is displayed in a numerator.

  As shown in Table 1 and Table 2, the capacitors of Examples 1 to 26 have an ESR of 17.1 to 19.4 mΩ, satisfy a set ESR of 30 mΩ or less, and have a capacitance of 52.9 to 53. 5 μF, satisfying a set capacitance of 45 μF or more, and a leakage current of 5.0 to 12.6 μA, satisfying a set leakage current of 20 μA or less, and compared with the capacitor of Comparative Example 1, ESR was low, capacitance was large, and leakage current was much less. And the capacitor | condenser of Examples 1-26 had low ESR and few leakage currents compared with the capacitor | condenser of Comparative Examples 2-4. Here, referring to the capacitors of Comparative Examples 1 to 4, the capacitor of Comparative Example 1 that has not been treated with the treatment liquid has an ESR of 89.0 mΩ and does not satisfy the set ESR of 30 mΩ or less. The capacitance was 38.1 μF, which did not satisfy the set capacitance of 45 μF or more, and the leakage current was 120.0 μA, far exceeding the set leakage current of 20 μA or less. The capacitors of Comparative Examples 2 to 4 also did not satisfy the set ESR of ESR greater than 30 mΩ and 30 mΩ or less, and the leakage current of 20 μA or less.

  Further, as shown in Tables 3 and 4, the capacitors of Examples 1 to 26 showed little increase in ESR and leakage current even after storage for 3,000 hours at 125 ° C., and also the decrease in capacitance. Less, the ESR is 21.0 to 24.1 mΩ, satisfies the set ESR of 30 mΩ or less, the capacitance is 48.4 to 49.5 μF, satisfies the set capacitance of 45 μF or more, and the leakage current Of 3.0 to 9.9 μA, satisfying a set leakage current of 20 μA or less, and no short circuit was generated.

  In contrast, the capacitor of Comparative Example 1 had a significantly increased ESR of 45631 mΩ, a large decrease in capacitance, and a significant increase in leakage current after storage at 125 ° C. for 3,000 hours. In addition, the capacitors of Comparative Examples 2 to 4 were also found to have a significant increase in ESR and a large increase in leakage current. In addition, the occurrence of short-circuit defects was also observed in the capacitors of Comparative Examples 1 to 4.

[Evaluation with a wound aluminum electrolytic capacitor (2)]
In this [Evaluation with a wound aluminum electrolytic capacitor (2)], 20 masses of a high boiling point organic solvent having a boiling point of 150 ° C. or higher or a high boiling point organic solvent having a boiling point of 150 ° C. or higher used as a solvent in preparing the treatment liquid is used. % Electrolytic capacitor containing a high-boiling organic solvent-containing liquid that is contained in an amount of not less than 100% and less than 100% by mass as a constituent material of the capacitor [that is, belongs to the invention of claim 2 of the present application (the second invention of the present application)] Electrolytic capacitor] is evaluated. The electrolytic capacitor which belongs to this is the electrolytic capacitor of Examples 27-40 in an Example.

Example 27
In place of the conductive polymer dispersion A used in the manufacture of the wound aluminum electrolytic capacitor in [Evaluation with a wound aluminum electrolytic capacitor (1)], a conductive polymer dispersion B (this conductive The conductive polymer in the dispersion B of the conductive polymer uses a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant, and the conductivity of the dispersion B of the conductive polymer. The capacitor element after the formation of the polymer layer was immersed in the treatment solution of Preparation Example 13 and allowed to stand for 1 minute, then taken out and immersed in the treatment solution of Preparation Example 13 instead of being dried at 180 ° C. for 30 minutes. [Evaluation with a wound aluminum electrolytic capacitor (1)], except that it was left for 1 minute and then taken out (ie, it was not dried at 180 ° C.). As in the case of], was prepared winding type aluminum electrolytic capacitor. In other words, in the wound aluminum electrolytic capacitor of Example 27, the configuration of the capacitor is obtained without drying (that is, without discharging from the capacitor) the ethylene glycol used as the solvent in the preparation of the treatment liquid of Preparation Example 13. It is a capacitor contained in a capacitor as a material, and belongs to the invention of claim 2 of the present application (that is, the second invention of the present application).

Examples 28-40
The wound aluminum electrolytic capacitor of Examples 28 to 40 was subjected to the same operation as Example 27 except that the treatment liquids of Preparation Examples 14 to 26 were separately used instead of the treatment liquid of Preparation Example 13. Manufactured.

  These capacitors contain the solvent used in the preparation of the treatment liquid in the condenser, and the capacitor of Example 28 contains γ-butyrolactone used as a solvent in the preparation of the treatment liquid of Preparation Example 14. In the capacitors of Examples 29 to 40, ethylene glycol used as a solvent in preparing the treatment liquids of Preparation Examples 15 to 26 was included in the capacitors.

Comparative Example 5
A wound aluminum electrolytic capacitor of Comparative Example 5 was produced in the same manner as in Example 27 except that the treatment liquid of Preparation Example 13 was not impregnated.

Comparative Examples 6-8
The wound aluminum of Comparative Examples 6 to 8 was prepared in the same manner as in Example 27 except that the comparative treatment liquids of Preparation Examples 30 to 32 were used separately in place of the treatment liquid of Preparation Example 13. An electrolytic capacitor was manufactured.

  In any of the capacitors of Comparative Examples 6 to 8, the capacitors contain ethylene glycol used as a solvent in preparing the comparative treatment liquids of Preparation Examples 30 to 32 used in the respective capacitors.

  For the wound aluminum electrolytic capacitors of Examples 27 to 40 and Comparative Examples 5 to 8 manufactured as described above, as in the case of the above-mentioned [Evaluation with a wound aluminum electrolytic capacitor (1)], Capacitance and leakage current were measured. The results are shown in Table 5 in the same manner as in Table 2.

  Moreover, the capacitors of Examples 27 to 40 and Comparative Examples 5 to 8 after the above characteristic measurement were stored at 125 ° C. for 3,000 hours, and the ESR, capacitance and leakage current of the capacitors after the storage were the same as described above. The occurrence of short-circuit defects was measured in the same manner as described above. The results are shown in Table 6 in the same manner as in Table 4.

  As shown in Table 5, the capacitors of Examples 27 to 40 had an ESR of 14.2 to 17.4 mΩ, satisfied a set ESR of 30 mΩ or less, and had a capacitance of 55.1 to 55.5 μF. Thus, the set capacitance of 45 μF or more is satisfied, the leakage current is 2.5 to 4.1 μA, the set leakage current of 20 μA or less is satisfied, and the ESR is lower than the capacitors of Comparative Examples 5 to 8, And there was little leakage current.

  In particular, the capacitor of Comparative Example 5 not impregnated with the treatment liquid had a very large leakage current of 120.0 μA and an ESR of 89.0 mΩ, which was very large.

  Further, as shown in Table 6, the capacitors of Examples 27 to 40 have little increase in ESR and leakage current due to storage at high temperature, and decrease in capacitance, and after storage at 125 ° C. for 3,000 hours. , The ESR is 15.3 to 19.0 mΩ, satisfies the set ESR of 30 mΩ or less, the capacitance is 52.1 to 52.8 μF, satisfies the set capacitance of 45 μF or more, and the leakage current is The set leakage current of 0.4 to 1.9 μA and 20 μA or less was satisfied, and no short circuit occurred.

  On the other hand, the capacitor of Comparative Example 5 has an ESR extremely large as 45631 mΩ after storage for 3,000 hours at 125 ° C., the leakage current is very large as 352.2 μA, and the capacitance is also reduced. The characteristics were greatly deteriorated during high-temperature storage, and the heat resistance was poor.

  Further, the capacitors of Comparative Examples 6 to 8 also have characteristic deterioration due to storage at a high temperature, and after storage for 3,000 hours at 125 ° C., an increase in ESR and an increase in leakage current are recognized and the set ESR is not satisfied. It was.

[Evaluation with tantalum solid electrolytic capacitors]
Example 41
In a state where the tantalum sintered body is immersed in a phosphoric acid solution having a concentration of 0.1%, a chemical conversion treatment is performed by applying a voltage of 100 V, and an oxide film is formed on the surface of the tantalum sintered body to form a dielectric layer. A capacitor element having a set ESR of 50 mΩ or less, a set capacitance of 15 μF or more, a rated voltage of 35 V, and a leakage current of 20 μA or less was produced.

  The capacitor element is made of the conductive polymer dispersion C (the conductive polymer in the conductive polymer dispersion C is a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant, It is obtained by oxidative polymerization using methylated ethylenedioxythiophene as a monomer) and left for 5 minutes, then taken out and dried at 150 ° C. for 30 minutes for 4 times. A functional polymer layer was formed.

  Next, the capacitor element on which the conductive polymer layer is formed is immersed in the treatment solution of Preparation Example 1 and left for 1 minute, then taken out and dried at 150 ° C. for 30 minutes. Polymer Dispersion D (This conductive polymer dispersion D is a conductive polymer dispersion obtained by oxidative polymerization of ethylenedioxythiophene with a sulfonated polyester as a dopant, as described above, and It is immersed in the conductive polymer dispersion B at a mass ratio of 5: 1), left for 5 minutes, taken out, and dried at 150 ° C. for 30 minutes, and repeated three times. A conductive polymer layer serving as an electrolyte was formed. Thereafter, the tantalum electrolytic capacitor of Example 41 was manufactured by covering the electrolyte layer composed of the conductive polymer layer with a carbon paste and a silver paste, followed by resin molding.

Examples 42-66
The tantalum electrolytic capacitors of Examples 42 to 66 were manufactured in the same manner as in Example 41 except that the treatment liquids of Preparation Examples 2 to 26 were separately used instead of the treatment liquid of Preparation Example 1. .

Comparative Example 9
A tantalum electrolytic capacitor of Comparative Example 9 was produced in the same manner as in Example 41 except that the treatment liquid of Preparation Example 1 was not used.

Comparative Examples 10-12
The tantalum electrolytic capacitors of Comparative Examples 10 to 12 were prepared in the same manner as in Example 41 except that the comparative treatment liquids of Preparation Examples 27 to 29 were used separately in place of the treatment liquid of Preparation Example 1. Manufactured.

  For the tantalum electrolytic capacitors of Examples 41 to 66 and Comparative Examples 9 to 12 manufactured as described above, ESR and capacitance were measured in the same manner as described above. The results are shown in Tables 7 and 8 in the same manner as in Tables 1 and 2.

  The capacitors of Examples 41 to 66 and Comparative Examples 9 to 12 after the above characteristic measurement were stored at 125 ° C. for 500 hours, and after the storage, ESR, capacitance and leakage current were measured in the same manner as described above, and short-circuited The occurrence of defects was examined. The results are shown in Tables 9 and 10 in the same manner as Tables 3 and 4.

  As shown in Table 7 and Table 8, the capacitors of Examples 41 to 66 have an ESR of 42.5 to 46.3 mΩ, satisfy a set ESR of 50 mΩ or less, and have a capacitance of 17.3 to 18. 4 μF, satisfying the set capacitance of 15 μF or more, the leakage current is 7.0 to 13.3 μA, satisfying the set leakage current of 20 μA or less, and compared with the capacitors of Comparative Examples 9 to 12 And ESR was low.

  In particular, the capacitor of Comparative Example 9 that was not treated with the treatment liquid had a large leakage current of 90.2 μA and an ESR of 114.0 mΩ.

  In addition, as shown in Tables 9 to 10, the capacitors of Examples 41 to 66 are less likely to increase in ESR, decrease in capacitance, and increase in leakage current due to storage at high temperature, and are stored at 125 ° C. for 500 hours. Later, the ESR is 44.8 to 49.8 mΩ, satisfies the set ESR of 50 mΩ or less, the capacitance is 15.8 to 16.8 μF, and satisfies the set capacitance of 15 μF or more, The leakage current was 2.6 to 11.9 μA, the set leakage current of 20 μA or less was satisfied, and no short circuit occurred.

  On the other hand, the capacitor of Comparative Example 9 was markedly increased in leakage current, increased ESR, and decreased in capacitance due to high temperature storage.

  As described above, according to the present invention, not only a wound aluminum electrolytic capacitor but also a tantalum electrolytic capacitor can provide a capacitor with low leakage current and excellent heat resistance.

Claims (3)

  In manufacturing an electrolytic capacitor using a conductive polymer as an electrolyte, a capacitor element having a porous body of at least one valve metal selected from the group consisting of aluminum, tantalum and niobium, and a dielectric layer made of an oxide film of the valve metal After the conductive polymer layer is formed on the capacitor element, at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester and at least a hydroxyl group bonded to the constituent carbon of the aromatic ring are formed on the capacitor element. At least one aromatic compound selected from the group consisting of an aromatic compound having one and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring, and a high-boiling organic solvent having a boiling point of 150 ° C. or higher Alternatively, a high boiling point organic solvent having a boiling point of 150 ° C. or higher is contained at 20% by mass or more and less than 100% by mass. High-boiling organic method of manufacturing an electrolytic capacitor which solvent-containing solution and the operation of impregnating a liquid containing a via to make at least once, characterized in that the production of electrolytic capacitors that.   In manufacturing an electrolytic capacitor using a conductive polymer as an electrolyte, a capacitor element having a porous body of at least one valve metal selected from the group consisting of aluminum, tantalum and niobium, and a dielectric layer made of an oxide film of the valve metal After the conductive polymer layer is formed on the capacitor element, at least one diester selected from the group consisting of phosphorous acid diester and phosphoric acid diester and at least a hydroxyl group bonded to the constituent carbon of the aromatic ring are formed on the capacitor element. At least one aromatic compound selected from the group consisting of an aromatic compound having one and an aromatic compound having at least one nitro group bonded to the constituent carbon of the aromatic ring, and a high-boiling organic solvent having a boiling point of 150 ° C. or higher Alternatively, a high boiling point organic solvent having a boiling point of 150 ° C. or higher is contained at 20% by mass or more and less than 100% by mass. High-boiling organic liquid impregnated comprising a solvent containing solution, then, method of manufacturing an electrolytic capacitor characterized in that to produce the electrolytic capacitor via performs an operation of drying at least once that. Conductive polymer layer formed on the capacitor element was impregnated with a dispersion liquid of the conductive polymer in the capacitor element, then, according to claim 1 or 2, wherein the operation of drying is obtained by forming by performing at least once Manufacturing method of the electrolytic capacitor.