JP7065683B2 - Oxidizing agent and dopant for manufacturing conductive polymers and their solutions, conductive polymers and their manufacturing methods, and electrolytic capacitors and their manufacturing methods. - Google Patents

Description

The present invention relates to an electrolytic capacitor having a small leakage current and a low equivalent series resistance and a method for manufacturing the same, a conductive polymer capable of constituting the electrolytic capacitor and a method for manufacturing the same, and oxidation for manufacturing the conductive polymer. It relates to an agent / dopant and its solution.

Due to its high conductivity, the conductive polymer is used as an electrolyte (solid electrolyte) such as an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, and a niobium electrolytic capacitor.

As the conductive polymer in this application, for example, a polymer obtained by chemically oxidatively polymerizing or electrolytically oxidatively polymerizing thiophene or a derivative thereof is used.

Organic sulfonic acid is mainly used as a dopant for chemical oxidation polymerization of the above thiophene or its derivative, and a transition metal is used as an oxidizing agent, and ferrous iron is said to be suitable among them. .. Then, a ferric salt of an organic sulfonic acid is usually used as an oxidizing agent and a dopant in a chemical oxidative polymerization of thiophene or a derivative thereof (for example, Patent Documents 1 to 3).

However, an electrolytic capacitor manufactured by using a conductive polymer synthesized by using a ferric salt of organic sulfonic acid as an oxidizing agent and a dopant as a solid electrolyte has a problem that a leakage current becomes large.

On the other hand, a technique for reducing the leakage current of such an electrolytic capacitor is also being studied. For example, Patent Document 4 proposes that an electrolytic capacitor is composed of a conductive polymer produced by using an oxidizing agent and a dopant containing ferric sulfonic acid and a specific phosphoric acid compound. ..

Japanese Unexamined Patent Publication No. 2002-138136 Japanese Patent Application Laid-Open No. 2003-160647 Japanese Unexamined Patent Publication No. 2004-265927 International Publication No. 2015/129515

The present invention uses a method different from the technique described in Patent Document 4, an electrolytic capacitor having a small leakage current and a low equivalent series resistance and a method for manufacturing the same, a conductive polymer capable of constituting the electrolytic capacitor, and a method for manufacturing the same. , And an oxidant / dopant for producing the conductive polymer and a solution thereof.

The oxidizing agent / dopant for producing a conductive polymer of the present invention (hereinafter, may be referred to as “oxidizing agent / dopant”) is the following (a) and (b).
(A) A benzenesulfonic acid containing at least one hydrocarbon group and having a total carbon number of 6 to 20 contained in the hydrocarbon group, and at least one hydrocarbon group contained in the hydrocarbon group. At least one organic sulfonic acid selected from the group consisting of naphthalene sulfonic acid having a total carbon number of 6 to 20 or a ferric salt thereof.
(B) Contains naphthalene sulfonic acid or a ferric salt thereof, and at least a part of (a) and (b) is a ferric salt, and the content of (b) is 100 parts by mass. The content of the above (a) at the time of the above is 1 to 50 parts by mass.

Further, in the oxidizing agent / dopant solution for producing a conductive polymer of the present invention (hereinafter, may be referred to as “oxidizing agent / dopant solution”), the oxidizing agent / dopant for producing a conductive polymer of the present invention is dissolved in a solvent. It is characterized by doing.

Further, the conductive polymer of the present invention uses the oxidant / dopant for producing a conductive polymer of the present invention, or uses the oxidant / dopant solution for producing a conductive polymer of the present invention to form thiophene or a dopant thereof. It is characterized in that it is formed by oxidative polymerization of at least one monomer selected from the group consisting of a derivative, pyrrole or a derivative thereof, and aniline or a derivative thereof.

Further, in the method for producing a conductive polymer of the present invention, the oxidizing agent / dopant for producing a conductive polymer of the present invention is used, or the oxidizing agent / dopant solution for producing a conductive polymer of the present invention is used. It is characterized in that at least one monomer selected from the group consisting of thiophene or a derivative thereof, pyrrole or a derivative thereof, and aniline or a derivative thereof is oxidatively polymerized to obtain a conductive polymer.

Further, the electrolytic capacitor of the present invention is characterized by having the conductive polymer of the present invention as a solid electrolyte.

The method for manufacturing an electrolytic capacitor of the present invention is characterized in that the conductive polymer obtained by the manufacturing method of the present invention is used as a solid electrolyte.

According to the present invention, in order to manufacture an electrolytic capacitor having a small leakage current and a low equivalent series resistance and a method for manufacturing the same, a conductive polymer capable of constituting the electrolytic capacitor and a method for manufacturing the same, and the conductive polymer. Can provide an oxidant / dopant and a solution thereof.

The oxidizing agent / dopant of the present invention comprises (a) a benzenesulfonic acid containing at least one hydrocarbon group and having a total carbon number of 6 to 20 contained in the hydrocarbon group, and at least one hydrocarbon group. At least one organic sulfonic acid selected from the group consisting of naphthalene sulfonic acid having a total carbon number of 6 to 20 contained in the hydrocarbon group or a ferric salt thereof, and (b) naphthalene sulfonic acid or It contains the ferric salt [naphthalene sulfonic acid or the ferric salt thereof which does not contain a substituent such as a hydrocarbon group]. At least a part of the above (a) and the above (b) is a ferric salt, and the content of the (a) is 1 part by mass or more when the content of the (b) is 100 parts by mass. It is 50 parts by mass or less.

The oxidant / dopant of the present invention acts as an oxidant during the polymerization of the conductive polymer, and is incorporated into the formed conductive polymer to function as a dopant. Then, the conductive polymer obtained by using the oxidant / dopant of the present invention or by using the oxidant / dopant solution of the present invention in which the oxidant / dopant of the present invention is dissolved in the solution (conductivity of the present invention). By using (polypolymer) as a solid electrolyte, the leakage current and equivalent series resistance (ESR) of the electrolytic capacitor can be reduced, and the heat resistance thereof can be improved.

The benzenesulfonic acid and its ferric salt containing a hydrocarbon group, and the naphthalenesulfonic acid and its ferric salt containing a hydrocarbon group may have one and a plurality of the above hydrocarbon groups. It may have, but it is preferably two or less.

(A) The hydrocarbon group contained in benzenesulfonic acid containing a hydrocarbon group and its ferric salt, which is a component, and naphthalenesulfonic acid containing a hydrocarbon group and its ferric salt are oxidizing agents and dopants. In an electrolytic capacitor having a conductive polymer polymerized using or a solution thereof, the carbon number needs to be a certain value or more from the viewpoint of reducing the leakage current. As described above, the component (a) may have at least one hydrocarbon group and may have a plurality of hydrocarbon groups, but the total number of carbon atoms of the hydrocarbon group (one hydrocarbon group). In the case, it is the number of carbon atoms of the hydrocarbon group, and when there are a plurality of hydrocarbon groups, the total number of carbon atoms of all the hydrocarbon groups; the same applies hereinafter) has 6 or more carbon atoms and 8 The above is preferable.

On the other hand, if the hydrocarbon group is too long, it becomes difficult to dissolve in a solvent when preparing an oxidizing agent / dopant solution or a polymerization solution for polymerizing a monomer, and a long hydrocarbon group is not easily available. Therefore, the above-mentioned hydrocarbon groups contained in (a) benzenesulfonic acid containing a hydrocarbon group and its ferric salt, and naphthalenesulfonic acid containing a hydrocarbon group and its ferric salt are not present. The total carbon number is 20 or less, preferably 18 or less.

That is, when the benzenesulfonic acid and its ferric salt, and the naphthalenesulfonic acid and its ferric salt contain a plurality of hydrocarbon groups, the carbon number of all the hydrocarbon groups is Each hydrocarbon group may have less than 6 carbon atoms as long as the total satisfies the above values.

The hydrocarbon group contained in the benzenesulfonic acid and its ferric salt, and the naphthalenesulfonic acid and its ferric salt include an alkyl group (that is, an ethyl group, a propyl group, a butyl group, a hexyl group and a heptyl group). , Octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group) are preferable.

Further, the benzenesulfonic acid containing a hydrocarbon group and its ferric salt, and the naphthalenesulfonic acid containing a hydrocarbon group and its ferric salt have one sulfonic acid group or a ferrous base of the sulfonic acid. It suffices to have a plurality of them, but it is preferable that the number is two or less.

Specific examples of the component (a) suitable for the oxidizing agent and dopant include hexylbenzenesulfonic acid, heptylbenzenesulfonic acid, octylbenzenesulfonic acid, nonylbenzenesulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, and dodecylbenzene. Sulphonic acid, tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, heptadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, nonadesylbenzenesulfonic acid, ecocilbenzenesulfonic acid, etc. Alkylbenzenesulfonic acid; hexylbenzenedisulfonic acid, heptylbenzenedisulfonic acid, octylbenzenedisulfonic acid, nonylbenzenedisulfonic acid, decylbenzenedisulfonic acid, undecylbenzenedisulfonic acid, dodecylbenzenedisulfonic acid, tridecylbenzenedisulfonic acid, tetradecylbenzene Alkylbenzene disulfonic acids such as disulfonic acid, pentadecylbenzenedisulfonic acid, hexadecylbenzenedisulfonic acid, heptadecylbenzenedisulfonic acid, octadecylbenzenedisulfonic acid, nonadesylbenzenedisulfonic acid, eicosylbenzenedisulfonic acid; hexylnaphthalenesulfonic acid, heptylnaphthalene. Sulphonic acid, octylnaphthalene sulfonic acid, nonylnaphthalene sulfonic acid, decylnaphthalene sulfonic acid, undecylnaphthalene sulfonic acid, dodecylnaphthalene sulfonic acid, tridecylnaphthalene sulfonic acid, tetradecylnaphthalene sulfonic acid, pentadecylnaphthalene sulfonic acid, hexadecylnaphthalene Alkylnaphthalene sulfonic acids such as sulfonic acid, heptadecylnaphthalene sulfonic acid, octadecylnaphthalene sulfonic acid, nonadesylnaphthalene sulfonic acid, eicosylnaphthalene sulfonic acid; dipropylnaphthalene sulfonic acid, dibutylnaphthalene sulfonic acid, dihexylnaphthalene sulfonic acid, diheptyl Dialkylnaphthalene sulfonic acid such as naphthalene sulfonic acid, dioctyl naphthalene sulfonic acid, dinonyl naphthalene sulfonic acid, didecyl naphthalene sulfonic acid; dipropyl naphthalene sulfonic acid, dibutyl naphthalene sulfonic acid, dihexyl naphthalene sulfonic acid, diheptyl naphthalene sulfonic acid, dioctyl Naphthalenedisulfonic acid, dinonylnaphthalenedisulfonic acid, Dialkylnaphthalenedisulfonic acids such as didecylnaphthalenedisulfonic acid; and the like, and ferric salts thereof. The oxidizing agent / dopant may contain only one of the above-exemplified components (a), or may contain two or more of them.

The compound (a) as a component can be obtained as follows. For example, it can be obtained by reacting an alkyl chloride or an alkyl bromide with a Lewis acid catalyst by a Friedel-Crafts reaction to obtain alkylbenzene or alkylnaphthalene, and then reacting sulfuric acid with alkylbenzene or alkylnaphthalene. Further, as the component (a), a commercially available product can also be used.

The component (b) of the oxidant / dopant is naphthalene sulfonic acid or a ferric salt thereof (ferric naphthalene sulfonate), and the oxidant / dopant is one of these as the component (b). May be contained, or both may be contained.

In the oxidant / dopant, for 1 mol of iron (iron atom) contained in the component (a) and the component (b), the organic sulfonic acid (organic sulfonic acid that is not a ferric salt) in the component (a) is used. And (b), the total amount of naphthalene sulfonic acid (naphthalen sulfonic acid that is not a ferric salt) among the components is 4.5 mol because the acid decomposes and the heat resistance change becomes large when the content is large. It is preferably less than, and more preferably 4 mol or less. On the other hand, in the oxidizing agent and dopant, the organic sulfonic acid in the component (a) and the naphthalene sulfonic acid in the component (b) with respect to 1 mol of iron (iron atom) contained in the component (a) and the component (b). The total amount of the above is preferably 2 mol or more because the polymerization rate is slow and the initial ESR of the electrolytic capacitor is high when the total amount is small.

Further, in the oxidizing agent / dopant, when the content of the component (b) is 100 parts by mass, the content of the component (a) is the conductive polymer polymerized by using the oxidizing agent / dopant and its solution. From the viewpoint of satisfactorily ensuring the effect of reducing the leakage current and the effect of improving the heat resistance of the electrolytic capacitor, the amount is 1 part by mass or more, preferably 5 parts by mass or more. However, if the ratio of the component (a) to the component (b) is too large, the ESR of the electrolytic capacitor having the conductive polymer polymerized by using the oxidizing agent / dopant and the solution thereof becomes large, which is suppressed. From the viewpoint, when the content of the component (b) in the oxidizing agent / dopant is 100 parts by mass, the content of the component (a) is 50 parts by mass or less, more preferably 40 parts by mass or less.

The oxidant / dopant may be composed of only the component (a) and the component (b), but may contain an organic sulfonic acid other than the components (a) and (b) and a ferric salt thereof. May be good.

Organic sulfonic acids other than the components (a) and (b) and ferric salts thereof include aromatic sulfonic acids such as benzenesulfonic acid or its derivatives, anthraquinone sulfonic acid or its derivatives; polystyrene sulfonic acid, sulfonated. High molecular weight sulfonic acid such as polyester, phenol sulfonic acid novolak resin, copolymer of styrene sulfonic acid and non-sulfonic acid-based monomer; chain sulfonic acid such as methane sulfonic acid, ethane sulfonic acid, propane sulfonic acid, butane sulfonic acid. ; These ferric salts;

When an organic sulfonic acid other than the component (a) and the component (b) or a ferric salt thereof is added to the oxidizing agent / dopant, the content in the oxidizing agent / dopant should be 15% by mass or less. Is preferable.

Further, in addition to the components (a) and (b), the above-mentioned other organic sulfonic acid and its ferric salt, other additives may be added to the oxidizing agent / dopant, if necessary. .. Examples of such additives include compounds having a glycidyl group (epoxide group) or ring-opening compounds thereof; polyhydric alcohols; polymerized compounds such as silane coupling agents; polysiloxanes, alcohol-soluble resins, polyethylene glycols and the like. Polymer; etc.

Examples of the compound having a glycidyl group or a ring-opening compound thereof include the following monoglycidyl compounds, the following diglycidyl compounds, glycerin diglycidyl ether, diglycerin tetraglycidyl ether, alcohol-soluble epoxy resin, alcohol-soluble polyglycerin polyglycidyl and the like. The ring-opening compound of the above, epoxy polysiloxane (the above-mentioned "polysiloxane" means "one having two or more siloxane bonds"), or a ring-opening compound thereof and the like are preferable.

Examples of the monoglycidyl compound include epoxypropanol (that is, glycidol), methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, epoxy butane (that is, glycidyl methane), epoxypentane (that is, glycidyl ethane), and epoxy. Hexane (ie, glycidylpropane), epoxyheptane (ie, glycidylbutane), epoxyoctane (ie, glycidylpentane), glycidoxypropyltrimethoxysilane, glycidoxypropylmethyldimethoxysilane, glycidoxypropyltriethoxysilane, Examples thereof include glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and glycidyl methacrylate.

Examples of the diglycidyl compound include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, pentylene glycol diglycidyl ether, hexylene glycol diglycidyl ether, glycerin diglycidyl ether, and diethylene glycol diglycidyl ether. Examples thereof include dipropylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

The amount of the compound having a glycidyl group or the ring-opening compound thereof added in the oxidizing agent / dopant is 5 to 100 when the total amount of the components (a) and (b) in the oxidizing agent / dopant is 100 parts by mass. It is preferably a mass portion.

The polyhydric alcohol preferably has 2 to 3 hydroxy groups in an aliphatic hydrocarbon having 2 to 10 carbon atoms, and specifically, ethylene glycol, propanediol, butanediol, pentandiol, hexanediol, and heptane. Examples thereof include diols, octanediols, nonanediols, decanediols and glycerol.

The amount of the polyhydric alcohol added to the oxidant / dopant is preferably 20 parts by mass or less when the total amount of the components (a) and (b) in the oxidant / dopant is 100 parts by mass.

The oxidant / dopant of the present invention can be used as it is, that is, in a solid state such as powder, but in the production of a conductive polymer, the oxidant / dopant is water, alcohol, or a mixture of water and alcohol. It is preferable to use it as a solution dissolved in a solvent such as a liquid (that is, the oxidizing agent and dopant solution of the present invention). By making the oxidant / dopant into a solution, the workability is improved, the mixed state with the monomer becomes more uniform, and the function as the oxidant / dopant can be more effectively exhibited.

Examples of alcohols that can be used as the solvent for the oxidant / dopant solution include monohydric alcohols such as methanol (methyl alcohol), ethanol (ethyl alcohol), propanol (propyl alcohol), butanol (butyl alcohol), ethylene glycol, and the like. Polyhydric alcohols such as propylene glycol, diethylene glycol, triethylene glycol and polyethylene glycol can be used, and among them, monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol and butanol are preferable.

However, if the oxidant / dopant solution contains water, precipitation of the oxidant / dopant may occur when the oxidant / dopant solution is stored for a long period of time. Therefore, from the viewpoint of enhancing the storage characteristics of the oxidant / dopant solution, the water content of the oxidant / dopant solution is preferably 3% by mass or less. From this point of view, it is more preferable to use alcohol as the solvent for the oxidizing agent and dopant solution.

The water content of the oxidizing agent / dopant solution referred to in the present specification means a value obtained by the curl fisher method (capacitive method), and for example, a curl fisher water measuring device (KF-) manufactured by Mitsubishi Chemical Analytech Co., Ltd. It can be measured using the 200 type) (the values described in the examples below are the values measured using this device).

The concentration of the oxidant / dopant in the oxidant / dopant solution is preferably 20% by mass or more from the viewpoint of increasing the oxidizing power and satisfactorily polymerizing the monomer during the polymerization of the conductive polymer. It is more preferably 25% by mass or more, and further preferably 30% by mass or more. However, if the amount of the oxidant / dopant in the oxidant / dopant solution is too large, the viscosity becomes too high, for example, it becomes difficult to penetrate into the capacitor element, and it may become difficult to manufacture the capacitor. Therefore, from the viewpoint of suppressing an excessive increase in viscosity of the oxidant / dopant solution, the concentration of the oxidant / dopant in the oxidant / dopant solution is preferably 70% by mass or less, and preferably 65% by mass or less. It is more preferably 60% by mass or less, and further preferably 60% by mass or less.

When producing a conductive polymer using the oxidizing agent / dopant of the present invention or the oxidizing agent / dopant solution of the present invention, thiophene or a derivative thereof, pyrrole or a derivative thereof, aniline or a derivative thereof may be used as the monomer. Although it is possible, it is particularly preferable to use thiophene or a derivative thereof. This is because the conductive polymer obtained by polymerizing thiophene or a derivative thereof has a good balance between conductivity and heat resistance, and it is easier to obtain an electrolytic capacitor having excellent capacitor characteristics as compared with other monomers. be.

Examples of the thiophene derivative in thiophene or a derivative thereof include 3,4-ethylenedioxythiophene, 3-alkylthiophene, 3-alkoxythiophene, 3-alkyl-4-alkoxythiophene, 3,4-alkylthiophene, 3. Examples thereof include 4-alkoxythiophene and alkylated ethylenedioxythiophene obtained by modifying the above 3,4-ethylenedioxythiophene with an alkyl group, and the number of carbon atoms of the alkyl group and the alkoxy group is 1 or more. Is preferable, and it is preferably 16 or less, more preferably 10 or less, and further preferably 4 or less.

The alkylated ethylenedioxythiophene obtained by modifying the above 3,4-ethylenedioxythiophene with an alkyl group will be described in detail. The above-mentioned 3,4-ethylenedioxythiophene and the alkylated ethylenedioxythiophene have the following general formulas ( It corresponds to the compound represented by 1).

General formula (1):

In the general formula (1), R ¹ is hydrogen or an alkyl group having 1 to 10 carbon atoms.

The compound in which ^R1 is hydrogen in the general formula (1) is 3,4-ethylenedioxythiophene, and when this is represented by the IUPAC name, "2,3-dihydro-thieno [3,4-b] ] [1,4] dioxin (2,3-Dihydro-thieno [3,4-b] [1,4] dioxin) ", but this compound has a more general name than indicated by the IUPAC name. Since it is often displayed as "3,4-ethylenedioxythiophene", in the present specification, this "2,3-dihydro-thieno [3,4-b] [1,4] dioxin" is referred to as "3". , 4-Ethylenedioxythiophene ”. When R ¹ in the general formula (1) is an alkyl group, the alkyl group preferably has 1 to 10 carbon atoms, and particularly preferably 1 to 4 carbon atoms. That is, as the alkyl group, a methyl group, an ethyl group, a propyl group, and a butyl group are particularly preferable, and when these are specifically exemplified, the compound in which R ¹ is a methyl group in the general formula (1) is represented by the IUPAC name. Then, "2-methyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2-Methyl-2,3-dihydro-thieno [3,4-b] [1,4] ] Dioxine) ”, but in the present specification, this is abbreviated as“ methylated ethylenedioxythiophene ”. The compound in which R ¹ is an ethyl group in the general formula (1) is represented by the IUPAC name as "2-ethyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2). -Ethyl-2,3-dihydro-thiono [3,4-b] [1,4] dioxin) ”, but in the present specification, this is abbreviated as“ ethylated ethylenedioxythiophene ”. ..

The compound in which R ¹ is a propyl group in the general formula (1) is represented by the IUPAC name as "2-propyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin (2). -Propyl-2,3-dihydro-thiono [3,4-b] [1,4] dioxin) ”, but in the present specification, this is abbreviated as“ propylated ethylenedioxythiophene ”. .. The compound in which R ¹ is a butyl group in the general formula (1) is represented by the IUPAC name as "2-butyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin. (2-Butyl-2,3-dihydro-thiono [3,4-b] [1,4] dioxin) ”, but in the present specification, this is abbreviated as“ butylated ethylenedioxythiophene ”. indicate. Further, "2-alkyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxine" is abbreviated as "alkylated ethylenedioxythiophene" in the present specification. Among those alkylated ethylenedioxythiophenes, methylated ethylenedioxythiophene, ethylated ethylenedioxythiophene, propylated ethylenedioxythiophene, and butylated ethylenedioxythiophene are preferable.

Then, 3,4-ethylenedioxythiophene (that is, 2,3-dihydro-thieno [3,4-b] [1,4] dioxine) and alkylated ethylenedioxythiophene (that is, 2-alkyl-2, It is preferable to use it in combination with 3-dihydro-thieno [3,4-b] [1,4] dioxin), and the mixing ratio thereof is 0.05: 1 to 1: 0.1 in terms of molar ratio. It is preferably 0.1: 1 to 1: 0.1, more preferably 0: 2: 1 to 1: 0.2, and even more preferably 0.3: 1 to 1: 0. 3 is particularly preferable.

In the production of the conductive polymer using the oxidizing agent / dopant of the present invention or the oxidizing agent / dopant solution of the present invention, the conductive polymer is usually produced when the conductive polymer is produced and when the electrolytic capacitor is produced. It can be applied to both the production of conductive polymers by so-called "in-situ polymerization".

Since thiophene and its derivatives as monomers are liquid at room temperature, they can be used as they are for polymerization, and in order to allow the polymerization reaction to proceed more smoothly, for example, methanol, ethanol, propanol, butanol, acetone, acetonitrile, etc. The monomer may be diluted with the organic solvent of the above and used as an organic solvent solution. As the monomer, a particularly preferable thiophene or a derivative thereof will be described as a representative, but pyrrole or a derivative thereof or aniline or a derivative thereof can also be used in the same manner as the above-mentioned thiophene or a derivative thereof.

The case of normally producing a conductive polymer (this "case of normally producing a conductive polymer" means that the conductive polymer is not produced by "in-situ polymerization" at the time of manufacturing an electrolytic capacitor. A mixture of the oxidant / dopant and solvent of the present invention or the oxidant / dopant solution of the present invention and the monomer thiophene or a derivative thereof is used (the mixing ratio is based on the mass of the oxidant). Combined dopant: the monomer is preferably 5: 1 to 15: 1), for example, by oxidative polymerization at 5 to 95 ° C. for 1 to 72 hours.

As described above, since the oxidant / dopant of the present invention is mixed with the monomer in the production of the electrolytic capacitor, the oxidant / dopant of the present invention has the components (a) and (b) before being mixed with the monomer. It is not necessary to prepare the oxidant / dopant by mixing with the oxidant / dopant of the present invention even if the component (a), the component (b) and the monomer are mixed at the same time. Since the state is similar to that of the mixture with the monomer, this may be done, and the monomer is previously mixed with one of the components (a) and (b), and ( Since a mixture of a) component and the other of (b) components is in the same state as the mixture of the oxidant / dopant of the present invention and the monomer, the oxidant / dopant of the present invention is an electrolytic capacitor. May be prepared as in the above example.

The oxidizing agent / dopant solution of the present invention has been developed so as to be suitable for producing a conductive polymer by so-called "in-situ polymerization" of thiophene or a derivative thereof, which is a monomer, particularly at the time of producing an electrolytic capacitor. Therefore, this will be described in detail below.

Further, electrolytic capacitors include aluminum electrolytic capacitors, tantalum electrolytic capacitors, niobular electrolytic capacitors, etc. Among the aluminum electrolytic capacitors, there are wound type aluminum electrolytic capacitors and laminated or flat plate type aluminum electrolytic capacitors. Since the oxidizing agent / dopant solution of the present invention can also be applied to the production of a wound type aluminum electrolytic capacitor, this will be described first.

First, as the capacitor element of the wound type aluminum electrolytic capacitor, after the surface of the aluminum foil is etched, a lead terminal is attached to the anode on which the dielectric layer is formed by the chemical conversion treatment, and the lead terminal is attached to the cathode made of the aluminum foil. It is preferable to use a product in which terminals are attached and the anode and cathode with lead terminals are wound around the separator.

Then, the winding type aluminum electrolytic capacitor is manufactured by using the above-mentioned capacitor element, for example, as follows.

The above condenser element is immersed in a mixture of the oxidizing agent / dopant solution of the present invention and a monomer (thiophene or a derivative thereof), pulled up (after being taken out), and then the monomer is polymerized at room temperature or at heating to polymerize the thiophene or a derivative thereof. After forming a solid electrolyte layer made of a conductive polymer having the polymer of the above as a polymer skeleton, the capacitor element having the solid electrolyte layer is exteriorized with an exterior material to manufacture a wound aluminum electrolytic capacitor.

Further, as described above, instead of immersing the condenser element in the mixture of the oxidizing agent / dopant solution of the present invention and the monomer, the monomer is diluted with the organic solvent such as methanol described above, and the monomer solution is used. After immersing the condenser element, pulling it up and drying it, immersing the condenser element in the oxidizing agent / dopant solution of the present invention, pulling it up, and then polymerizing the monomer at room temperature or under heating, or the condenser element first. After immersing in the oxidizing agent / dopant solution of the present invention, pulling it up and drying it, the capacitor element is dipped in the monomer, pulled up, and then the monomer is polymerized at room temperature or under heating. Circular aluminum electrolytic capacitors are manufactured.

In the manufacture of electrolytic capacitors other than the above-mentioned wound type aluminum electrolytic capacitors, such as laminated or flat plate type aluminum electrolytic capacitors, tantalum electrolytic capacitors, and niobium electrolytic capacitors, the perforated valve metal such as aluminum, tantalum, and niobium as capacitor elements. A capacitor element having an anode made of a body and a dielectric layer made of an oxide film of the valve metal thereof is used as an oxidizing agent / dopant solution of the present invention in the same manner as in the case of the wound type aluminum electrolytic capacitor. Immerse in a mixture of and the monomer and pull up to polymerize the monomer at room temperature or heating, or immerse the capacitor element in a monomer solution, pull it up and dry it, and then use the capacitor element as the oxidizing agent of the present invention. After soaking in a dopant solution and pulling up, the monomer is polymerized at room temperature or at heating, or the capacitor element is dipped in the oxidizing agent and dopant solution of the present invention, pulled up and dried, and then the capacitor element is placed in the monomer. After immersing in and pulling up, the monomer is polymerized at room temperature or under heating, the capacitor element is washed, and then dried. Then, by repeating these steps to form a solid electrolyte layer made of a conductive polymer, carbon paste and silver paste are applied, dried, and then the exterior is used to form a laminated or flat plate type aluminum electrolytic capacitor and tantalum. Electrolytic capacitors, niobium electrolytic capacitors, etc. are manufactured.

In the above description, a case where the capacitor element is immersed in a mixture of the oxidant / dopant solution of the present invention and a monomer, the above-mentioned monomer solution or the oxidant dopant solution of the present invention, and the capacitor element is impregnated with them will be described. However, the capacitor elements may be coated with them, for example, by spraying, to impregnate them.

In the production of the conductive polymer by "in-situ polymerization" at the time of manufacturing the above-mentioned conductive polymer or electrolytic capacitor, the oxidizing agent / dopant solution and the monomer (thiophene or a derivative thereof) or the monomer solution of the present invention are used. The ratio of the total amount of the components (a) and (b) to be used as an oxidizing agent and a dopant and the amount of the monomer is preferably 2: 1 to 8: 1 in terms of mass ratio. The "in-situ polymerization" is carried out, for example, at 10 to 300 ° C. for 1 to 180 minutes.

Further, in the production of the electrolytic capacitor, as described above, after producing the conductive polymer using the oxidizing agent / dopant solution of the present invention, the π-conjugated conductive polymer is dispersed on the conductive polymer. A conductive polymer layer may be formed by using a liquid to form an electrolytic capacitor in which a solid electrolyte is formed of both of them.

As the above-mentioned π-conjugated conductive polymer, a π-conjugated conductive polymer using a polymer anion as a dopant is used. This polymer anion is mainly composed of high molecular weight sulfonic acid, and specific examples thereof include polystyrene sulfonic acid, sulfonated polyester, phenolsulfonic acid novolak resin, styrenesulfonic acid and non-sulfonic acid-based monomer (methacrylic acid). Examples thereof include a copolymer with an ester, an acrylic acid ester, an alkoxysilane compound containing an unsaturated hydrocarbon or a hydrolyzate thereof).

Next, the means for synthesizing a conductive polymer by oxidatively polymerizing a monomer (explained by taking the most representative thiophene or a derivative thereof as an example) using the above polymer anion as a dopant will be described. Sulphonic acid, sulfonated polyester, phenol sulfonic acid novolak resin, etc., and copolymers of styrene sulfonic acid and non-sulfonic acid-based monomers are all aqueous liquids composed of water or a mixture of water and a water-miscible solvent. Since it is soluble in water, oxidative polymerization is carried out in water or an aqueous solution.

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

As the oxidative polymerization for producing the conductive polymer, either chemical oxidative polymerization or electrolytic oxidative polymerization can be adopted.

For example, persulfate is used as an oxidizing agent in performing chemical oxidative polymerization, and examples of the persulfate include ammonium persulfate, sodium persulfate, potassium persulfate, calcium persulfate, barium persulfate and the like. Is used.

In the chemical oxidative polymerization, the conditions at the time of the polymerization are not particularly limited, but the temperature at the time of the chemical oxidative polymerization is preferably 5 ° C. to 95 ° C., more preferably 10 ° C. to 30 ° C., and the polymerization. The time is preferably 1 hour to 72 hours, more preferably 8 hours to 24 hours.

The electrolytic oxidation polymerization can be performed with a constant current or a constant voltage. For example, when the electrolytic oxidation polymerization is performed with a constant current, the current value is preferably 0.05 mA / cm ² to 10 mA / cm ² and 0.2 mA / cm. ² to 4 mA / cm ² is more preferable, and when electrolytic oxidation polymerization is performed at a constant voltage, the voltage is preferably 0.5 V to 10 V, more preferably 1.5 V to 5 V. The temperature at the time of 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 addition, in electrolytic oxidation polymerization, ferrous sulfate or ferric sulfate may be added as a catalyst.

The conductive polymer obtained as described above is obtained in a state of being dispersed in water or an aqueous solution immediately after polymerization, and contains persulfate as an oxidizing agent, iron sulfate used as a catalyst, and its decomposition products. Includes. Therefore, it is preferable to disperse the impurities by applying a dispersion of the conductive polymer containing the impurities to a disperser such as an ultrasonic homogenizer, a high-pressure homogenizer, or a planetary ball mill, and then remove the metal component with a cation exchange resin. 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, and more preferably 0.01 μm or more. It is more preferably 0.1 μm or more. After that, it is preferable to remove the one produced by the decomposition of the oxidizing agent or the catalyst by an ethanol precipitation method, an ultrafiltration method, an anion exchange resin or the like.

In the present invention, an electrolytic polymer may be configured by using a conductive polymer obtained by oxidatively polymerizing a monomer such as thiophene or a derivative thereof using an oxidizing agent / dopant or a solution thereof as described above as a solid electrolyte. It is also possible to construct an electrolytic polymer by using the above-mentioned conductive polymer and a conductive polymer obtained from a dispersion of a π-conjugated conductive polymer using a polymer anion as a dopant as a solid electrolyte. good. Further, they include a conductive auxiliary liquid containing 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 and an aromatic compound having at least one hydroxyl group or carboxyl group. You may also configure an electrolytic capacitor.

Examples of the high boiling point organic solvent having a boiling point of 150 ° C. or higher that can be used in the conductive auxiliary liquid include γ-butyrolactone (boiling point: 203 ° C.), butanediol (boiling point: 230 ° C.), and dimethylsulfoxide (boiling point: 189 ° C.). ), Sulfolane (boiling point: 285 ° C.), N-methylpyrrolidone (boiling point: 202 ° C.), dimethylsulfolane (boiling point: 233 ° C.), ethylene glycol (boiling point: 198 ° C.), diethylene glycol (boiling point: 244 ° C.), triethyl phosphate. (Boiling point: 215 ° C.), tributyl phosphate (289 ° C.), triethylhexyl phosphate [215 ° C. (4 mmHg)], polyethylene glycol and the like can be mentioned.

Further, as the above-mentioned aromatic compound having at least one hydroxyl group (a hydroxyl group bonded to a constituent carbon of an aromatic ring, which does not mean an −OH moiety such as in a carboxyl group) or a carboxyl group. , Benzene-based, naphthalene-based, and anthracene-based ones can be used, and specific examples thereof include hydroxybenzenecarboxylic acid, nitrophenol, dinitrophenol, trinitrophenol, aminonitrophenol, and hydroxy. Anisol, hydroxydinitrobenzene, dihydroxydinitrobenzene, alkylhydroxyanisole, hydroxynitroanisole, hydroxynitrobenzenecarboxylic acid (ie, hydroxynitrobenzoic acid), dihydroxynitrobenzenecarboxylic acid (ie, dihydroxynitrobenzoic acid), phenol, dihydroxybenzene, tri Hydroxybenzene, dihydroxybenzenecarboxylic acid, trihydroxybenzenecarboxylic acid, hydroxybenzenedicarboxylic acid, dihydroxybenzenedicarboxylic acid, hydroxytoluenecarboxylic acid, nitronaphthol, aminonaphthol, dinitronaphthol, hydroxynaphthalenecarboxylic acid, dihydroquinaphthalenecarboxylic acid, tri Hydroxynaphthalene carboxylic acid, hydroxynaphthalenedicarboxylic acid, dihydroxynaphthalenedicarboxylic acid, hydroxyanthracen, dihydroxyanthracene, trihydroxyanthracene, tetrahydroxyanthracene, hydroxyanthracene carboxylic acid, hydroxyanthracendicarboxylic acid, dihydroxyanthracene dicarboxylic acid, tetrahydroxyanthracendione, benzene Examples thereof include carboxylic acid, benzenedicarboxylic acid, naphthalenecarboxylic acid and naphthalenedicarboxylic acid.

Further, at least one binder selected from the group consisting of an epoxy compound or a hydrolyzate thereof, a silane compound or a hydrolyzate thereof, and polyalcohol is added to a high boiling point organic solvent or a conductive auxiliary liquid having a boiling point of 150 ° C. or higher. It can also be contained.

According to the present invention, an oxidant / dopant for producing a conductive polymer capable of producing a conductive polymer suitable for producing an electrolytic capacitor having a small leakage current, a low ESR, and excellent heat resistance, and a dopant thereof. Solutions can be provided, and any of them can be used to provide a conductive polymer suitable for producing electrolytic capacitors with low leakage current, low ESR, and excellent heat resistance. Further, by using the conductive polymer as a solid electrolyte, it is possible to provide an electrolytic capacitor having a small leakage current, a low ESR, and an excellent heat resistance.

Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

[Synthesis of component (a) of oxidizing agent and dopant]
Synthesis of dipropylnaphthalenedisulfonic acid Using aluminum chloride as a catalyst, 2 mol of 1-bromopropane was reacted with 1 mol of naphthalene and purified by distillation to obtain dipropylnaphthalene. Dipropylnaphthalenedisulfonic acid was synthesized by reacting 1 mol of dipropylnaphthalene with 2 mol of sulfuric acid.

Synthesis of dibutylnaphthalenedisulfonic acid Dibutylnaphthalenedisulfone in the same manner as the synthesis of dipropylnaphthalenedisulfonic acid except that 1-bromobutane was added instead of 1-bromopropane (1 mol of naphthalene and 2 mol of 1-bromobutane). Acid was synthesized.

Synthesis of dihexylnaphthalenedisulfonic acid Dihexyl is the same as the synthesis of dipropylnaphthalenedisulfonic acid except that 1-chlorohexane is added instead of 1-bromopropane (1 mol of naphthalene and 2 mol of 1-chlorohexane). Naphthalene sulfonic acid was synthesized.

Synthesis of didecyl naphthalenedisulfonic acid Didecyl is the same as the synthesis of dipropylnaphthalenedisulfonic acid except that 1-chlorodecane was added instead of 1-bromopropane (1 mol of naphthalene to 2 mol of 1-chlorodecane). Naphthalene sulfonic acid was synthesized.

Synthesis of diethylnaphthalenedisulfonic acid diethylnaphthalenedisulfonic acid was synthesized in the same manner as the synthesis of dipropylnaphthalenedisulfonic acid except that bromoethane was added in place of 1-bromopropane (1 mol of naphthalene and 2 mol of bromoethane). ..

Synthesis of didodecylnaphthalenedisulfonic acid Similar to the synthesis of dipropylnaphthalenedisulfonic acid except that 1-chlorododecane was added instead of 1-bromopropane (1 mol of naphthalene to 2 mol of 1-chlorododecane). Dodecyl naphthalene disulfonic acid was synthesized.

[Preparation of oxidizer and dopant solution]
In the preparation of this oxidant / dopant solution, the oxidant / dopant solutions of Examples 1 to 19 and Comparative Examples 1 to 5 are shown. These oxidant / dopant solutions of Examples 1 to 19 are used for manufacturing the wound type aluminum solid electrolytic capacitors of Examples 20 to 38 described later, and the oxidant / dopant solutions of Comparative Examples 1 to 5 are the same. It is used for manufacturing the wound type aluminum solid electrolytic capacitor of Comparative Examples 6 to 9.

Example 1
10 kg of a butanol solution (water content in the solution was 1% by mass) in which 4.5 kg of ferric naphthalene sulfonic acid salt (molar ratio of iron to naphthalene sulfonic acid was 1: 2.5) was prepared was prepared.

Next, 10 kg of the butanol solution of ferric naphthalene sulfonic acid: 10 kg was placed in a reaction vessel having an internal volume of 20 L, and in that solution, 450 g of dipropylnaphthalenedisulfonic acid: 450 g of ferric naphthalene sulfonate: relative to 100 parts by mass. , Dipropylnaphthalenedisulfonic acid: 10 parts by mass) was added. Then, the solid content in this solution was adjusted to 45% by mass, and the water content in the solution was adjusted to 1% by mass to prepare an oxidizing agent / dopant solution.

Example 2
Example 1 except that dibutylnaphthalenedisulfonic acid: 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (dibutylnaphthalene sulfonic acid: 10 parts by mass with respect to ferrous naphthalene sulfonic acid: 100 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Example 3
Example 1 except that dihexylnaphthalenedisulfonic acid: 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (dihexylnaphthalenedisulfonic acid: 10 parts by mass with respect to ferrous naphthalenesulfonate: 100 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Example 4
Dipropylnaphthalenedisulfonic acid: Instead of 450 g, dinonylnaphthalenedisulfonic acid (manufactured by King Industries): 45 g was added (ferrous naphthalenesulfonic acid: 100 parts by mass, dinonylnaphthalenedisulfonic acid: 1 mass). Except for part), an oxidizing agent / dopant solution was prepared in the same manner as in Example 1.

Example 5
Oxidizing agent in the same manner as in Example 4 except that the amount of dinonylnaphthalene sulfonic acid added was changed to 225 g (ferrous naphthalene sulfonic acid: 100 parts by mass, dinonyl naphthalene sulfonic acid: 5 parts by mass). A concurrent dopant solution was prepared.

Example 6
Oxidizing agent in the same manner as in Example 4 except that the amount of dinonylnaphthalenedisulfonic acid added was changed to 450 g (ferrous naphthalenesulfonic acid: 100 parts by mass, dinonylnaphthalenedisulfonic acid: 10 parts by mass). A concurrent dopant solution was prepared.

Example 7
An oxidizing agent / dopant solution was prepared in the same manner as in Example 6 except that the water content was adjusted to be 2% by mass.

Example 8
An oxidizing agent / dopant solution was prepared in the same manner as in Example 6 except that the water content was adjusted to 3% by mass.

Example 9
An oxidizing agent / dopant solution was prepared in the same manner as in Example 6 except that the water content was adjusted to 4% by mass.

Example 10
Oxidizing agent in the same manner as in Example 4 except that the amount of dinonylnaphthalenedisulfonic acid added was changed to 900 g (ferrous naphthalenesulfonic acid: 100 parts by mass, dinonylnaphthalenedisulfonic acid: 20 parts by mass). A concurrent dopant solution was prepared.

Example 11
Oxidizing agent in the same manner as in Example 4 except that the amount of dinonylnaphthalenedisulfonic acid added was changed to 1800 g (ferrous naphthalenesulfonic acid: 100 parts by mass, dinonylnaphthalenedisulfonic acid: 40 parts by mass). A concurrent dopant solution was prepared.

Example 12
10 kg of a butanol solution (water content in the solution was 1% by mass) in which 4.5 kg of ferric naphthalene sulfonic acid salt (molar ratio of iron to naphthalene sulfonic acid was 1: 2.7) was prepared was prepared.

Next, a butanol solution of ferric naphthalene sulfonate: 10 kg was placed in a reaction vessel having an internal volume of 20 L, and the molar ratio of ferric dinonylnaphthalenedisulfonic acid (iron to dinonylnaphthalenedisulfonic acid was found in the reaction vessel. 1: 2.7): 45 g (ferrous naphthalene sulfonate: 1 part by mass with respect to 100 parts by mass of ferric naphthalene sulfonate) was added. Then, the solid content in this solution was adjusted to 45% by mass, and the water content in the solution was adjusted to 1% by mass to prepare an oxidizing agent / dopant solution.

Example 13
Example 12 except that the amount of ferric dinonylnaphthalenedisulfonate added was changed to 900 g (ferric naphthalenesulfonate: 100 parts by mass, ferric dinonylnaphthalenedisulfonate: 20 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Example 14
Example 12 except that the amount of ferric dinonylnaphthalenedisulfonate added was changed to 1800 g (ferric naphthalenesulfonate: 100 parts by mass, ferric dinonylnaphthalenedisulfonate: 40 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Example 15
10 kg of a butanol solution (water content in the solution was 1% by mass) in which 4.5 kg of ferric naphthalene sulfonic acid salt (molar ratio of iron to naphthalene sulfonic acid was 1: 3.5) was prepared was prepared.

Next, a butanol solution of ferric naphthalene sulfonate: 10 kg was placed in a reaction vessel having an internal volume of 20 L, and the molar ratio of ferric dinonylnaphthalenedisulfonic acid (iron to dinonylnaphthalenedisulfonic acid was found in the reaction vessel. 1: 3.5): 450 g (dinonylnaphthalenede ferric sulfonate: 10 parts by mass with respect to 100 parts by mass of ferric naphthalene sulfonate) was added. Then, the solid content in this solution was adjusted to 45% by mass, and the water content in the solution was adjusted to 1% by mass to prepare an oxidizing agent / dopant solution.

Example 16
10 kg of a butanol solution (water content in the solution was 1% by mass) in which 4.5 kg of ferric naphthalene sulfonic acid salt (molar ratio of iron to naphthalene sulfonic acid was 1: 4.3) was prepared was prepared.

Next, a butanol solution of ferric naphthalene sulfonate: 10 kg was placed in a reaction vessel having an internal volume of 20 L, and the molar ratio of ferric dinonylnaphthalenedisulfonic acid (iron to dinonylnaphthalenedisulfonic acid was found in the reaction vessel. 1: 4.3): 450 g (ferrous phthalene sulfonate: 10 parts by mass with respect to 100 parts by mass of dinonylphthalenedi sulfonate) was added. Then, the solid content in this solution was adjusted to 45% by mass, and the water content in the solution was adjusted to 1% by mass to prepare an oxidizing agent / dopant solution.

Example 17
Performed except that didecylnaphthalenedisulfonic acid: 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (didecylnaphthalenedisulfonic acid: 10 parts by mass with respect to ferrous naphthalenesulfonate: 100 parts by mass). An oxidizing agent / dopant solution was prepared in the same manner as in Example 1.

Example 18
Dipropylnaphthalenedisulfonic acid: Instead of 450 g, dinonylnaphthalenesulfonic acid (manufactured by King Industries): 450 g was added (ferrous naphthalenesulfonic acid: 100 parts by mass, dinonylnaphthalenesulfonic acid: 10 mass by mass). Except for part), an oxidizing agent / dopant solution was prepared in the same manner as in Example 1.

Example 19
Dodecylbenzene sulfonic acid (manufactured by King Industries): 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (sodium dodecylbenzene sulfonic acid: 10 parts by mass with respect to 100 parts by mass of ferric naphthalene sulfonic acid). Except for this, an oxidizing agent / dopant solution was prepared in the same manner as in Example 1.

Comparative Example 1
An oxidizing agent / dopant solution was prepared in the same manner as in Example 1 except that dipropylnaphthalenedisulfonic acid was not added.

Comparative Example 2
Example 1 except that dibutylnaphthalenedisulfonic acid: 2700 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (dibutylnaphthalene sulfonic acid: 60 parts by mass with respect to ferrous naphthalene sulfonate: 100 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Comparative Example 3
Example 1 except that diethylnaphthalenedisulfonic acid: 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (ferrous naphthalenesulfonic acid: 100 parts by mass, diethylnaphthalenedisulfonic acid: 10 parts by mass). An oxidant / dopant solution was prepared in the same manner as above.

Comparative Example 4
Dipropylnaphthalenedisulfonic acid: 450 g was added instead of dipropylnaphthalenedisulfonic acid: 450 g (diferren naphthalenesulfonic acid ferrous: 100 parts by mass, didodecylun naphthalenedisulfonic acid: 10 parts by mass). An attempt was made to prepare an oxidizing agent / dopant solution in the same manner as in Example 1, but didodecylnaphthalenedisulfonic acid was precipitated and a good solution could not be prepared.

Comparative Example 5
Instead of dipropylnaphthalene sulfonic acid: 450 g, p-toluenesulfonic acid (manufactured by Gangnam Kako Co., Ltd.): 450 g was added (ferrous naphthalenesulfonic acid: 100 parts by mass, p-toluenesulfonic acid: 10 mass by mass). An oxidizing agent / dopant solution was prepared in the same manner as in Example 1 except for the part).

The configurations of the oxidizing agent and dopant solutions of Examples 1 to 19 and Comparative Examples 1 to 5 are shown in Tables 1 and 2. The didodecylnaphthalenedisulfonic acid used in Comparative Example 4 and the p-toluenesulfonic acid used in Comparative Example 5 do not correspond to the component (a), but in Table 2, in order to facilitate comparison with each Example. It is shown in the column of (a) component. Further, in Tables 1 and 2, the "amount of the component (a) with respect to the component (b)" means the content (parts by mass) of the component (b) with respect to 100 parts by mass, and further, "iron". "Ratio to 1 mol" means the ratio of the total amount of the component (a) and the component (b) to 1 mol of iron contained in the component (a) and the component (b).

In the evaluation of the oxidizing agent and dopant solutions of Examples 1 to 19 and Comparative Examples 1 to 3 and 5 prepared as described above, a conductive polymer was produced using these, and the conductive polymer was used as a solid electrolyte. This was done by measuring the characteristics of the wound aluminum solid electrolytic capacitors of Examples 20 to 38 and Comparative Examples 6 to 9 manufactured using the above.

[Manufacturing and evaluation of solid electrolytic capacitors]
Here, 3,4-ethylenedioxythiophene is used as a monomer, and the oxidizing agent and dopant solution of Examples 1 to 19 is used, and the wound type aluminum solid electrolytic capacitor of Examples 20 to 38 (the set capacitance is set). The set ESR is 40 mΩ or less at 38 μF or more), and the capacitor characteristics of the wound aluminum solid electrolytic capacitors of Comparative Examples 6 to 9 prepared by using the oxidizing agent and dopant solution of Comparative Examples 1 to 5 are compared.

Example 20
The aluminum foil whose surface has been etched is immersed in an aqueous solution of ammonium adipate having a concentration of 12% by mass, and in this state, a voltage of 40 V is applied to the aluminum foil to form a dielectric layer on the surface of the aluminum foil to form an anode. A lead body was attached to this anode. Further, a lead body was attached to a cathode made of aluminum foil. These anodes and cathodes were superposed and wound via a separator to prepare a capacitor element for a wound type aluminum solid electrolytic capacitor.

The capacitor element was immersed in a monomer solution prepared by adding 80 mL of methanol to 3,4-ethylenedioxythiophene: 20 mL, pulled up, and then dried at 50 ° C. for 10 minutes. Then, the capacitor element is immersed in the oxidizing agent / dopant solution of Example 1, pulled up, heated at 70 ° C. for 2 hours, and further heated at 180 ° C. for 1 hour to obtain 3,4-ethylenedioxythiophene. Was polymerized to form a solid electrolyte layer made of a conductive polymer having a polymer of 3,4-ethylenedioxythiophene as a polymer skeleton on the surface of the condenser element. This capacitor element was exteriorized with an exterior body to produce a wound type aluminum solid electrolytic capacitor having a set capacitance of 38 μF or more and a set ESR of 40 mΩ or less.

Examples 21-38 and Comparative Examples 6-9
A wound aluminum solid electrolytic capacitor was produced in the same manner as in Example 20 except that the oxidant / dopant solution was changed to that of Examples 2 to 19 or Comparative Examples 1 to 3 and 5.

Capacitance, ESR and leakage current were measured as initial characteristics of the wound aluminum solid electrolytic capacitors of Examples 20 to 38 and Comparative Examples 6 to 9 by the following methods, respectively.

(Capacitance)
It was measured at 120 Hz under the condition of 25 ° C. using an LCR meter (4284A) manufactured by HEWLETT PACKARD.

(ESR)
It was measured at 100 kHz under the condition of 25 ° C. using an LCR meter (4284A) manufactured by HEWLETT PACKARD.

(Leak current)
A voltage of 16 V was applied to each capacitor at 25 ° C. for 60 seconds, and then the leakage current was measured using a digital oscilloscope.

The above measurement was performed for 10 samples for each sample. These results are shown in Table 3. Table 3 shows the average value of the 10 measured values rounded to the second decimal place for capacitance and ESR, and the average of the 10 measured values rounded to the nearest whole for leakage current. Shows the value.

As shown in Table 3, the windings of Examples 20 to 38 having a conductive polymer synthesized by using an oxidizing agent / dopant solution containing the component (a) and the component (b) in an appropriate ratio in a solid electrolyte. The type aluminum solid electrolytic capacitor was able to reduce the leakage current as compared with the electrolytic capacitors of Comparative Examples 1, 3 and 5 using the oxidant / dopant solution containing no component (a).

The electrolytic capacitor of Comparative Example 7 having a conductive polymer as a solid electrolyte synthesized by using an oxidizing agent / dopant solution in which the ratio of the component (a) to the component (b) is too large is ESR more than that of the example. Became high.

[Evaluation of heat resistance of solid electrolytic capacitors]
After storing each of 10 wound aluminum solid electrolytic capacitors of Examples 20 to 38 and Comparative Examples 6 to 9 at 125 ° C. for 1000 hours, the capacitance and ESR were measured by the same method as described above. These results are shown in Table 4. In Table 4, for the capacitance, the rate of change (%) from the measured value at the time of initial characteristic evaluation of the capacitance obtained by the following formula is shown, and for ESR, the measured value at the time of this heat resistance evaluation. The rate of change (times) obtained by dividing the value by the measured value at the time of initial characteristic evaluation is described.

Rate of change (%) from the initial characteristic evaluation measurement value of the heat resistance evaluation measurement value of capacitance:
Rate of change (%) = 100 × (heat resistance evaluation measurement value-initial characteristic evaluation measurement value)
÷ Initial characteristic evaluation measurement value

As shown in Table 4, the wound aluminum solid electrolytic capacitors of Examples 20 to 38 are compared with the electrolytic capacitors of Comparative Example 9 in which p-toluenesulfonic acid is used instead of the component (a), for example, after high temperature storage. The decrease in capacitance and the increase in ESR were suppressed, and it had good heat resistance.

Claims (12)

The following (a) and (b)
(A) A benzenesulfonic acid containing at least one hydrocarbon group and at least one sulfonic acid group and having a total carbon number of 6 to 20 contained in the hydrocarbon group, and at least one hydrocarbon group and at least one. At least one organic sulfonic acid or a ferric salt thereof selected from the group consisting of naphthalene sulfonic acid containing one sulfonic acid group and having a total carbon number of 12 to 20 contained in the hydrocarbon group.
(B) Contains naphthalene sulfonic acid or a ferric salt thereof, and at least a part of the above (a) and the above (b) is a ferric salt.
An oxidizing agent and dopant for producing a conductive polymer, wherein the content of (a) is 1 to 50 parts by mass when the content of (b) is 100 parts by mass. The total amount of the organic sulfonic acid in the (a) and the naphthalene sulfonic acid in the (b) is less than 4.5 mol with respect to 1 mol of the iron contained in the (a) and the (b). The oxidizing agent and dopant for producing a conductive polymer according to claim 1. The oxidant / dopant solution for producing a conductive polymer according to claim 1 or 2, wherein the oxidant / dopant for producing a conductive polymer is dissolved in a solvent. The oxidant / dopant solution for producing a conductive polymer according to claim 3, wherein the concentration of the oxidant / dopant for producing a conductive polymer is 20 to 70% by mass. The oxidizing agent / dopant solution for producing a conductive polymer according to claim 3 or 4, which contains water, alcohol, or a mixed solution of water and alcohol as the solvent. The oxidizing agent / dopant solution for producing a conductive polymer according to any one of claims 3 to 5, wherein the water content is 3% by mass or less. Oxidize at least one monomer selected from the group consisting of thiophene or a derivative thereof, pyrrole or a derivative thereof, and aniline or a derivative thereof using the oxidizing agent and dopant for producing a conductive polymer according to claim 1 or 2. A conductive polymer characterized by being polymerized. At least one selected from the group consisting of thiophene or a derivative thereof, pyrrole or a derivative thereof, and aniline or a derivative thereof using the oxidizing agent / dopant solution for producing a conductive polymer according to any one of claims 3 to 6. A conductive polymer characterized by being formed by oxidative polymerization of the monomer of. Oxidize at least one monomer selected from the group consisting of thiophene or a derivative thereof, pyrrole or a derivative thereof, and aniline or a derivative thereof using the oxidizing agent and dopant for producing a conductive polymer according to claim 1 or 2. A method for producing a conductive polymer, which comprises polymerizing to obtain a conductive polymer. At least one selected from the group consisting of thiophene or a derivative thereof, pyrrole or a derivative thereof, and aniline or a derivative thereof using the oxidizing agent / dopant solution for producing a conductive polymer according to any one of claims 3 to 6. A method for producing a conductive polymer, which comprises oxidatively polymerizing the above-mentioned monomers to obtain a conductive polymer. An electrolytic capacitor with a solid electrolyte,
An electrolytic capacitor comprising the conductive polymer according to claim 7 or 8 as the solid electrolyte. A method of manufacturing an electrolytic capacitor having a solid electrolyte.
A method for producing an electrolytic capacitor, which comprises using the conductive polymer produced by the method for producing a conductive polymer according to claim 9 or 10 as the solid electrolyte.