JP6415146B2 - Conductive polymer dispersion for electrolytic capacitor production and electrolytic capacitor produced using the same. - Google Patents

Description

  The present invention relates to a dispersion of a conductive polymer for the production of an electrolytic capacitor containing at least a conductive polymer synthesized with a specific polymer anion as a dopant, a phosphite diester, and a dispersion medium, and the same. Relates to the electrolytic capacitor.

  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, electrolytic capacitors using a conductive polymer made of an organic sulfonic acid transition metal salt such as ferric organic sulfonate as an oxidant and dopant have a large leakage current, especially 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 type 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. There has been a problem that it cannot be applied to the production of electrolytic capacitors. In addition, the conductive polymer is synthesized with polystyrene sulfonic acid as a dopant, so heat resistance is poor, and it cannot be said that leakage current is sufficiently reduced, and further improvement in characteristics is considered necessary. .

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

  In view of the above circumstances, the present invention provides a dispersion of a conductive polymer suitable for producing an electrolytic capacitor having low ESR, low leakage current, and excellent heat resistance, and It aims at providing the electrolytic capacitor which has the said characteristic using it.

  In order to solve the above-mentioned problems, the present invention has been intensively researched and conducted by dispersing a conductive polymer synthesized using a specific polymer anion as a dopant and phosphite diester in a dispersion medium. The present inventors have found that a polymer dispersion is suitable for producing an electrolytic capacitor having low ESR, low leakage current, and excellent heat resistance.

  That is, the present invention provides a conductive high compound synthesized by using as a dopant at least one polymer anion selected from the group consisting of sulfonated polyester, phenolsulfonic acid novolak resin, and a copolymer of styrenesulfonic acid and a non-sulfonic acid monomer. The present invention relates to a dispersion of a conductive polymer for producing an electrolytic capacitor, comprising at least a molecule, a phosphite diester, and a dispersion medium.

  Further, the present invention also includes an electrolytic capacitor manufactured using the conductive polymer dispersion.

  That is, the present invention is an electrolytic capacitor having an electrolyte layer on a dielectric layer of a capacitor element, the electrolyte layer comprising a sulfonated polyester, a phenol sulfonate novolak resin, and styrene sulfonate and a non-sulfonate monomer. The present invention relates to an electrolytic capacitor comprising at least a conductive polymer synthesized using at least one polymer anion selected from the group consisting of a copolymer as a dopant, and phosphite diester.

  ADVANTAGE OF THE INVENTION According to this invention, the dispersion liquid of the conductive polymer for electrolytic capacitor manufacture suitable for manufacturing an electrolytic capacitor with low ESR, few leakage currents, and excellent heat resistance can be provided. In addition, an electrolytic capacitor having low ESR, low leakage current, and excellent heat resistance can be provided by using the conductive polymer dispersion.

  The conductive polymer dispersion for producing an electrolytic capacitor of the present invention coexists the conductive polymer and the phosphite diester in the state of the dispersion. Since the viscosity of the dispersion liquid is not significantly increased during storage unlike the phosphoric acid diester in No. 3, the electrolytic capacitor can be used without any trouble even in industrial use.

  In the present invention, since the conductive polymer is synthesized using a specific polymer anion as a dopant, a monomer for obtaining the conductive polymer will be described first, and then used when the monomer is polymerized. The dopant will be described.

  As the monomer, thiophene or a derivative thereof, pyrrole or a derivative thereof, aniline or a derivative thereof can be used, and thiophene or a derivative thereof is particularly suitable.

  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.

  In the configuration of the conductive polymer dispersion for producing the electrolytic capacitor of the present invention, the conductive polymer includes specific polymer anions, that is, sulfonated polyester, phenol sulfonate novolak resin, styrene sulfonate and non-sulfone. Those synthesized using at least one polymer anion selected from the group consisting of copolymers with acid monomers as a dopant are used.

  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. Examples of the copolymer include styrene sulfonic acid, acrylic acid ester, methacrylic acid ester and unsaturated hydrocarbons. Those composed of a copolymer of at least one non-sulfonic acid monomer selected from the group consisting of alkoxysilane compounds or hydrolysates thereof, styrenesulfonic acid and acrylic acid, methacrylic acid, vinylbenzenecarboxylic acid, Examples thereof include those composed of a copolymer with a non-sulfonic acid monomer such as vinyltoluene, and in particular, the former styrene sulfonic acid, an acrylic ester, a methacrylic ester and an unsaturated hydrocarbon-containing alkoxysilane compound or its At least one selected from the group consisting of hydrolysates A copolymer of non-sulfonated monomers are preferred. The copolymer of styrene sulfonic acid and non-sulfonic acid monomer exists as a polymer anion in the conductive polymer and functions as a dopant.

  Among the above-mentioned copolymers of styrene sulfonic acid and non-sulfonic acid monomer, the particularly preferred former, ie, styrene sulfonic acid, acrylic ester, methacrylic ester and unsaturated hydrocarbon-containing alkoxysilane compound or a hydrolyzate thereof. Details of a copolymer with at least one non-sulfonic acid monomer selected from the group (hereinafter, this may be referred to as “copolymer of styrene sulfonic acid and non-sulfonic acid monomer (1)”) To explain, in synthesizing the copolymer (1) of styrene sulfonic acid and non-sulfonic acid monomer, the non-sulfonic acid monomer copolymerized with styrene sulfonic acid includes acrylic acid ester, methacrylic acid ester and non-sulfonic acid monomer. Saturated hydrocarbon-containing alkoxysilane compound or its hydrolyzate Although at least one selected from the group consisting of the above is used, examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, stearyl acrylate, cyclohexyl acrylate, and acrylic. Diphenylbutyl acid, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, sodium sulfohexyl acrylate, glycidyl acrylate, methyl glycidyl acrylate, hydroxyalkyl acrylate, ie hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxy acrylate Hydroxyalkyl acrylate such as propyl and hydroxybutyl acrylate can be used, but hydroxymethyl acrylate, hydroxyethyl acrylate , Hydroxypropyl acrylate, acrylic acid hydroxyalkyl having a carbon number 1 to 4 alkyl groups such as acrylic acid hydroxybutyl are preferable from the properties 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 methacrylic acid ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 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, hydroxy methacrylate Hexyl, hydroxyalkyl methacrylate such as hydroxystearyl methacrylate, Hydroxypolyoxyethylene oxalate, methoxyhydroxypropyl methacrylate, ethoxyhydroxypropyl methacrylate, dihydroxypropyl methacrylate, dihydroxybutyl methacrylate, etc. can be used, especially hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, Hydroxyalkyl methacrylate having 1 to 4 carbon atoms in the alkyl group such as hydroxybutyl methacrylate is preferable from the viewpoint of properties as a dopant when copolymerized with styrenesulfonic 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 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 acrylic acid esters, methacrylic 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 acrylic acid ester, methacrylic 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 an acrylic ester, a methacrylic ester and 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.

  The polymer anions such as the sulfonated polyester, phenolsulfonic acid novolak resin, and copolymer of styrenesulfonic acid and non-sulfonic acid monomer can be used alone or in combination of two or more. it can.

  And a monomer such as thiophene or a derivative thereof using at least one polymer anion selected from the group consisting of the sulfonated polyester, phenolsulfonic acid novolak resin, and a copolymer of styrenesulfonic acid and a non-sulfonic acid monomer. The oxidative polymerization of is carried out in water or in an aqueous liquid composed of a mixture 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.

  As the oxidative polymerization for synthesizing the conductive polymer, either chemical oxidative polymerization or electrolytic oxidative polymerization can be employed.

  The oxidizing agent for performing the chemical oxidative polymerization is not particularly limited, but a non-transition metal oxidizing agent is preferable. Regardless of the type of oxidant used in the synthesis of the conductive polymer, the leakage current can be reduced by adding phosphite diester, but the leakage current is increased in the conductive polymer. This is because the leakage current can be reduced more efficiently when the transition metal salt that causes the generation of the salt is not included.

  For example, persulfate is used as the non-aqueous transition metal-based oxidizing agent as described above. 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, the conductive polymer is removed by removing the oxidant and catalyst produced in the dispersion by ethanol precipitation, ultrafiltration, anion exchange resin, cation exchange resin, etc. It is preferable to further increase the degree of dispersion by applying the dispersion liquid 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.

  Furthermore, in the production of an electrolytic capacitor, an alkali may be added to the conductive polymer dispersion in order to prevent corrosion of the capacitor element. By adding the alkali as described above, the pH of the dispersion of the conductive polymer is adjusted to pH 2 to 10, preferably 2.5 to 5.5, whereby corrosion of the capacitor element can be prevented and long-term reliability can be prevented. Can be improved.

  The alkali as described above is not particularly limited. For example, ammonia, methylamine, ethylamine, propylamine, butylamine, ethoxypropylamine, pentylamine, hexylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, 2-Amino-2-hydroxymethyl-1,3-propanediol, 3-dimethylamino-1,2-propanediol, 2-amino-1,3-propanediol and the like can be suitably used.

  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.

  Next, phosphorous acid diester will be described. As said phosphorous acid diester, what was comprised by the at least 1 sort (s) of group chosen from the acid group of phosphorous acid and a C1-C18 alkyl group, a benzyl group, and a phenyl group is preferable. And as said alkyl group, a C1-C12 thing is more preferable and a C1-C8 thing is further more preferable. The benzyl group or phenyl group may be one in which an alkyl group is bonded.

  Specific examples of the above phosphite diester include, for example, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, diisopropyl phosphite, dibutyl phosphite, diamyl phosphite, dihexyl phosphite. , Diheptyl phosphite, dioctyl phosphite, diethylhexyl phosphite, didecyl phosphite, dilauryl phosphite, didotecil phosphite, dimyristyl phosphite, dipalmethyl phosphite, distearyl phosphite, phosphorus phosphite Examples include dibenzyl acid, diphenyl phosphite, and dihexyl phenyl phosphite. Among these phosphite diesters, in particular, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, diisopropyl phosphite, dibutyl phosphite, diamyl phosphite, dihexyl phosphite, phosphorus phosphite Preference is given to dialkyl phosphites having 1 to 8 carbon atoms in the alkyl group, such as diheptyl acid, dioctyl phosphite and diethylhexyl phosphite, dibenzyl phosphite and diphenyl phosphite.

  In the present invention, such a phosphite diester is used as a constituent material of a conductive polymer dispersion for producing an electrolytic capacitor. This phosphite diester reduces ESR of the electrolytic capacitor and leaks. This is because it contributes to reducing the current and providing an electrolytic capacitor with low ESR and low leakage current.

  Water or an aqueous liquid is suitable as a dispersion medium for dispersing the conductive polymer or phosphite diester, and the water or aqueous liquid used in the synthesis of the conductive polymer is applied as the water or aqueous liquid. be able to.

  As a content rate in the dispersion liquid of the said phosphorous acid diester, 0.5-500% on the mass reference | standard with respect to a conductive polymer (Namely, phosphorous acid diester is 0 with respect to 100 mass parts of conductive polymers. 0.5 to 500 parts by mass) is preferable. If the ratio of the phosphite diester to the conductive polymer is less than the above, the effect of reducing the ESR due to the phosphite diester and reducing the leakage current may not be sufficiently exhibited, If the ratio of the phosphite diester to the conductive polymer is higher than the above, the viscosity of the dispersion may increase, the phosphite diester may not be dispersed, and the ESR may increase.

  The ratio of the ester to the conductive polymer of phosphorous acid is, as described above, in the range of 0.5 to 500%, more preferably 1% or more, and further preferably 3% or more, Moreover, 100% or less is more preferable, and 50% or less is further more preferable.

  The dispersion containing the conductive polymer as described above and the phosphite diester further contains at least one glycidyl compound or silane compound or a polymer obtained by reacting at least one selected from them. It can be included.

  For example, it is preferable that the conductive polymer dispersion contains at least one glycidyl compound or silane compound because the withstand voltage of the obtained electrolytic capacitor 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, glycerol diglycidyl ether, or the like can be used epoxy resin.

  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, polysiloxane, and the like can be used.

  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 a dispersion of a conductive polymer containing at least the conductive polymer and phosphite diester, followed by drying. Is called.

  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. Done.

  As described above, the dispersion of the conductive polymer for producing the electrolytic capacitor of the present invention contains at least phosphite diester in addition to the conductive polymer. When expressing the dispersion, When all of these are expressed, it becomes long. Therefore, only the conductive polymer is represented as a dispersion of the conductive polymer.

  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.

  Then, the conductive polymer containing phosphite diester 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, in order to improve the adhesion between the conductive polymer and the dielectric layer of the capacitor element, it is preferable to add a binder made of a polymer compound to the dispersion of the conductive polymer. 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.

  In the production of an electrolytic capacitor, the conductive polymer layer constituting the electrolyte layer needs to include those formed using the conductive polymer dispersion of the present invention. The electrolyte may not be derived from the conductive polymer dispersion of the present invention, and such a conductive polymer layer may be a conductive polymer other than the conductive polymer dispersion of the present invention. It may be formed by using a dispersion of the above, or may be formed by so-called “in-situ polymerization” in which the conductive polymer layer is formed during the manufacturing process of the electrolytic capacitor.

  When preparing a dispersion of a conductive polymer other than the dispersion of the conductive polymer of the present invention as described above, the monomer is polymerized by oxidizing agent or "in-situ polymerization" during the synthesis of the conductive polymer. The oxidizing agent is not particularly limited, but it is preferable to use a non-transition metal type.

  Examples of the non-transition metal oxidant used when the monomer is polymerized by such “in-situ polymerization” include persulfates such as persulfuric acid, ammonium persulfate, sodium persulfate, and potassium persulfate, and peroxidation. Examples of the dopant used in combination with hydrogen and benzoyl peroxide include, for example, benzenesulfonic acid, benzenedisulfonic acid, toluenesulfonic acid, phenolsulfonic acid, nitrobenzenesulfonic acid, gresolsulfonic acid, naphthalenedisulfonic acid, Naphthalene trisulfonic acid, naphthalene sulfonic acid, methyl naphthalene sulfonic acid, propyl naphthalene sulfonic acid, butyl naphthalene sulfonic acid, anthraquinone sulfonic acid, etc., which are in the acid state or their non-imidazole salts, etc. Used in the form of transfer metal salt. The polymer anion can also be used as a dopant.

  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.

  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 comparative examples,% indicating the concentration of a solution or dispersion or% indicating purity is% based on mass unless otherwise specified. In the following examples,% indicating the ratio of phosphorous acid diester to conductive polymer is also% based on mass.

  In addition, an Example is an Example of the electroconductive polymer dispersion liquid for electrolytic capacitor manufacture in Examples 1 to 17 (hereinafter referred to as “conductive polymer dispersion liquid” in the examples). Examples 18 to 46 show examples of electrolytic capacitors. And the characteristic evaluation of the dispersion liquid of the conductive polymer of Examples 1-17 is performed by evaluating the characteristic of the electrolytic capacitor of Examples 18-46 manufactured using it.

[Preparation of dispersion of conductive polymer]
Example 1
1 L of pure water was added to a 2 L separable flask with a stirrer, and 170 g of sodium styrenesulfonate and 30 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.

Then, 600 g of a 3% aqueous solution of a copolymer of styrene sulfonic acid and hydroxyethyl acrylate is placed 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 dropped therein. Attach an anode to the vessel, attach two stainless steel plates (3 cm wide x 3 cm long x 2 mm thick) for the cathode in the solution, and stir with a stirring blade made of polytetrafluoroethylene. Electrolytic oxidation polymerization was carried out 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. Then, the excess anion was removed by performing the process and filtration with an anion exchange resin.

  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. Purified water was added to this liquid to adjust the concentration of the content to 3% to obtain 300 g of a conductive polymer dispersion having a concentration of 3%. To the dispersion of the conductive polymer having a concentration of 3%, 1.2 g of diethyl phosphite was added, and the concentration of the conductive polymer was adjusted to 1.8%. A polymer dispersion was obtained. The ratio of diethyl phosphite to the conductive polymer in the dispersion of the conductive polymer of Example 1 was 13%.

  Moreover, when the particle size distribution of the conductive polymer in the conductive polymer dispersion of Example 1 was measured by ELS-Z manufactured by Otsuka Electronics, the average particle size was 110 nm.

Example 2
1 L of pure water was added to a 2 L separable flask equipped with a stirrer, and 170 g of sodium styrenesulfonate and 30 g of 3-methacryloxypropyltriethoxysilane 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 3-methacryloxypropyltriethoxysilane 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 3-methacryloxypropyl triethoxysilane was obtained.

  The obtained styrene sulfonic acid and 3-methacryloxypropyltriethoxysilane copolymer had a weight average molecular weight of 100,000 using a gel filtration column and dextran as a standard product.

  In place of the aqueous solution of the copolymer of styrene sulfonic acid and hydroxyethyl acrylate having a concentration of 3% in Example 1, 3 of the copolymer of styrene sulfonic acid and 3-methacryloxypropyltriethoxysilane was used. Except for using a% aqueous solution, the same operation as in Example 1 was performed to obtain 300 g of a conductive polymer dispersion having a concentration of 3%. After adding 1.2 g of diethyl phosphite to the dispersion of the conductive polymer having a concentration of 3% and stirring to dissolve it, purified water is further added to adjust the concentration of the conductive polymer to 2. The dispersion of the conductive polymer of Example 2 was obtained by adjusting to 0%. The ratio of diethyl phosphite to the conductive polymer in the dispersion of the conductive polymer of Example 2 was 13%.

  Moreover, when the particle size distribution of the conductive polymer in the electropolymer dispersion of Example 2 was measured by ELS-Z manufactured by Otsuka Electronics Co., Ltd., the average particle size was 120 nm.

Example 3
A conductive polymer dispersion of Example 3 was obtained in the same manner as in Example 1 except that 2.0 g of dimethyl phosphite was added instead of 1.2 g of diethyl phosphite. . The ratio of dimethyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 3 was 22%.

Example 4
A conductive polymer dispersion of Example 4 was obtained in the same manner as in Example 1 except that 1.2 g of dibutyl phosphite was added instead of 1.2 g of diethyl phosphite. . The ratio of dibutyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 4 was 13%.

Example 5
A conductive polymer dispersion of Example 5 was obtained in the same manner as in Example 1 except that 0.9 g of diethylhexyl phosphite was added instead of 1.2 g of diethyl phosphite. It was. The ratio of diethylhexyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 5 was 10%.

Example 6
A conductive polymer dispersion of Example 6 was obtained in the same manner as in Example 2 except that 1.5 g of diphenyl phosphite was added instead of 1.2 g of diethyl phosphite. . The ratio of diphenyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 6 was 17%.

Example 7
After 400 g of a 3% aqueous solution of sulfonated polyester [Plus Coat Z-561 (trade name), weight average molecular weight 27,000, manufactured by Kyoyo Chemical Industry 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 of 7% as measured at 105 ° C. To 100 g of the 7% dispersion, 10 g of dimethyl sulfoxide and 40 g of diglycerol are added as a high boiling point solvent, and further 1.4 g of diethyl phosphite is added and dissolved by stirring to dissolve the conductive polymer. A dispersion was obtained. The ratio of diethyl phosphite to the conductive polymer in the conductive polymer dispersion was 20%.

  Dispersion of the conductive polymer having the sulfonated polyester thus obtained as a dopant and the copolymer of styrene sulfonic acid and hydroxyethyl acrylate of Example 1 as a dopant. And a conductive polymer having a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant and a conductive polymer having a sulfonated polyester as a dopant. A mixed dispersion was obtained as a dispersion of the conductive polymer of Example 7. The ratio of diethyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 7 was 18%.

Example 8
Instead of the dispersion of the conductive polymer using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate of Example 1 as a dopant, the styrene sulfonic acid of Example 2 and 3-methacryloxypropyltriethoxysilane A conductive polymer dispersion of Example 8 was obtained in the same manner as in Example 7, except that a conductive polymer dispersion containing a copolymer as a dopant was used. That is, the conductive polymer dispersion of Example 8 is a conductive polymer having a copolymer of styrenesulfonic acid and 3-methacryloxypropyltriethoxysilane as a dopant and a conductive polymer having a sulfonated polyester as a dopant. The amount of diethyl phosphite relative to the conductive polymer in the conductive polymer dispersion of Example 8 was 18%.

Example 9
The same operations as in Example 7 were performed except that the dispersion of the conductive polymer having the copolymer of styrene sulfonic acid and hydroxyethyl acrylate of Example 1 as a dopant was not added. A conductive polymer dispersion No. 9 was obtained. That is, the conductive polymer dispersion of Example 9 is a conductive polymer dispersion containing only sulfonated polyester as a dopant, and contains diethyl phosphite. The diethyl phosphite The ratio with respect to the conductive polymer was 20%.

Example 10
Conductive polymer dispersion using sulfonated polyester as a dopant in Example 7 (Thus, the conductive polymer dispersion in Example 7 refers to the one before addition of diethyl phosphite. The same operation as in Example 7 was carried out except that 2.1 g of dimethyl phosphite was used instead of 1.4 g of diethyl phosphite as the phosphite diester added to the following) A dispersion of the conductive polymer of Example 10 was obtained. The conductive polymer of Example 10 is a mixed dispersion of a conductive polymer having a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant and a conductive polymer having a sulfonated polyester as a dopant. The ratio of diethyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 10 is 22%, and the amount of dimethyl phosphite to the conductive polymer is 4%. The total ratio of diethyl phosphite and dimethyl phosphite to the conductive polymer was 26%.

Example 11
Except for using 1.0 g of dibutyl phosphite instead of 1.4 g of diethyl phosphite as the phosphite diester added to the dispersion of the conductive polymer having the sulfonated polyester as a dopant in Example 7. All of the same operations as in Example 7 were performed to obtain a conductive polymer dispersion of Example 11. The conductive polymer dispersion of Example 11 is a mixture of a conductive polymer having a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant and a conductive polymer having a sulfonated polyester as a dopant. The ratio of diethyl phosphite to the conductive polymer in the dispersion of Example 11 is 10%, and the ratio of dibutyl phosphite to the conductive polymer is 4%. The total ratio of diethyl phosphite and dibutyl phosphite to the functional polymer was 14%.

Example 12
Except for using 0.7 g of dibenzyl phosphite instead of 1.4 g of diethyl phosphite, as the phosphite diester added to the dispersion of the conductive polymer having the sulfonated polyester as a dopant in Example 7. All of the same operations as in Example 7 were performed to obtain a conductive polymer dispersion of Example 12. The conductive polymer dispersion of Example 12 is a mixture of a conductive polymer having a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant and a conductive polymer having a sulfonated polyester as a dopant. The ratio of diethyl phosphite to the conductive polymer in the dispersion of the conductive polymer of Example 12 was 10%, and the ratio of dibenzyl phosphite to the conductive polymer was 4%. The total ratio of diethyl phosphite and dibenzyl phosphite to the conductive polymer was 14%.

Example 13
1 L of pure water was added to a 2 L separable flask equipped with a stirrer, and 190 g of sodium styrenesulfonate and 10 g of glycidyl methacrylate were added thereto. And 1g of ammonium persulfate was added to the solution as an oxidizing agent, and the polymerization reaction of styrene sulfonic acid and glycidyl methacrylate 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 glycidyl methacrylate was obtained.

  The obtained styrene sulfonic acid and glycidyl methacrylate copolymer had a weight average molecular weight of 90,000 estimated using a gel filtration column and dextran as a standard.

  Then, instead of the aqueous solution of the copolymer of styrene sulfonic acid and hydroxyethyl acrylate having a concentration of 3% in the conductive polymer dispersion of Example 1, the copolymer of styrene sulfonic acid and glycidyl methacrylate was used. Except for using a 3% aqueous solution of coalescence, all the same operations as in Example 1 were performed to obtain 300 g of a conductive polymer dispersion having a concentration of 3%. To the dispersion of the conductive polymer, 1.2 g of diisopropyl phosphite was added and dissolved by stirring, and then purified water was added to adjust the concentration of the conductive polymer to 2%. Thus, a conductive polymer dispersion of Example 13 was obtained. The ratio of diisopropyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 13 was 13%.

  When the particle size distribution of the conductive polymer in the conductive polymer dispersion of Example 13 was measured by ELS-Z manufactured by Otsuka Electronics, the average particle size was 110 nm.

Example 14
The dispersion of the conductive polymer of Example 14 was obtained by adding 2-amino-1,3-propanediol to the dispersion of the conductive polymer of Example 1 and adjusting the pH to 3.0. The ratio of diethyl phosphite to the conductive polymer in the dispersion of the conductive polymer of Example 14 was 13%.

Example 15
N-butyldiethanolamine was added to the conductive polymer dispersion of Example 2 to adjust the pH to 3.6, whereby the conductive polymer dispersion of Example 15 was obtained. The ratio of diethyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 15 was 13%.

Example 16
Dispersion of the conductive polymer of Example 16 by adding 2-amino-2-hydroxymethyl-1,3-propanediol to the dispersion of the conductive polymer of Example 13 and adjusting the pH to 3.3. A liquid was obtained. The ratio of diisopropyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 16 was 13%.

Example 17
1 L of pure water was added to a 2 L separable flask equipped with a stirrer, and 190 g of sodium styrenesulfonate and 10 g of glycidyl methacrylate were added thereto. And 1g of ammonium persulfate was added to the solution as an oxidizing agent, and the polymerization reaction of styrene sulfonic acid and glycidyl methacrylate 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 glycidyl methacrylate was obtained.

  The obtained styrene sulfonic acid and glycidyl methacrylate copolymer had a weight average molecular weight of 90,000 estimated using a gel filtration column and dextran as a standard.

200 g of a 3% aqueous solution of a copolymer of styrene sulfonic acid and glycidyl methacrylate and a phenol sulfonic acid novolak resin [manufactured by Konishi Chemical Industries, Ltd., having a weight average molecular weight of 20,000 and R ¹ in the formula (2) is H ( 200 g of a 3% aqueous solution of hydrogen) was added to a 1 L container, and 3 g of ammonium persulfate was added as an oxidizing agent, and then dissolved by stirring with a stirrer. Next, 0.4 g of a 40% aqueous solution of ferric sulfate was added, and while stirring, 3 mL of ethylenedioxythiophene was slowly dropped therein, and chemical oxidative 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 4%. The conductive polymer of Example 17 was added to 100 g of this 4% solution by adding 10 g of ethylene glycol and 40 g of diglycerol as a high boiling point solvent, and further adding 1.4 g of diisopropyl phosphite and dissolving them by stirring. A dispersion was obtained. The ratio of diisopropyl phosphite to the conductive polymer in the conductive polymer dispersion of Example 17 was 35%.

Comparative Example 1
A conductive polymer dispersion of Comparative Example 1 was obtained in the same manner as in Example 1 except that diethyl phosphite was not added. That is, the conductive polymer dispersion of Comparative Example 1 is a conductive polymer dispersion using a copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant, and added with phosphorous acid diester. It is not.

Comparative Example 2
Conductive polymer dispersion using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate in Example 1 as a dopant (in this way, the conductive polymer dispersion in Example 1 Diethyl phosphite was added to the dispersion of the conductive polymer having the sulfonated polyester in Example 7 as a dopant, without adding diethyl phosphite to the same as before adding diethyl acid, the same applies hereinafter) Except for the above, the same operation as in Example 7 was performed to obtain a conductive polymer dispersion of Comparative Example 2.

Comparative Example 3
Instead of 1.2 g of diethyl phosphite, 1.2 g of phosphorous acid was used instead of 1.2 g of diethyl phosphite with respect to the dispersion of the conductive polymer using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate in Example 1 as a dopant Except for the addition, the same operation as in Example 1 was performed to obtain a conductive polymer dispersion of Comparative Example 3. The ratio of phosphorous acid to the conductive polymer in the conductive polymer dispersion of Comparative Example 3 was 13%.

Comparative Example 4
In place of 1.2 g of diethyl phosphite, 1.2 g of phosphorous acid was added to the conductive polymer dispersion using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant in Example 1. Example 7 was conducted except that 1.4 g of phosphorous acid was added instead of 1.4 g of diethyl phosphite to the dispersion of the conductive polymer having the sulfonated polyester as a dopant in Example 7. A conductive polymer dispersion of Comparative Example 4 was obtained in the same manner as described above. The ratio of phosphorous acid to the conductive polymer in the conductive polymer dispersion of Comparative Example 4 was 18%.

Comparative Example 5
In place of 1.2 g of diethyl phosphite, 1.2 g of diethyl phosphate was added to the conductive polymer dispersion using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant in Example 1. Except that, the same operation as in Example 1 was performed to obtain a conductive polymer dispersion of Comparative Example 5. The ratio of diethyl phosphate to the conductive polymer in the conductive polymer dispersion of Comparative Example 5 was 13%.

Comparative Example 6
In place of 1.2 g of diethyl phosphite, 1.2 g of diethyl phosphate was added to the conductive polymer dispersion using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate as a dopant in Example 1. Example 7 was conducted except that 1.4 g of diethyl phosphate was added instead of 1.4 g of diethyl phosphite to the dispersion of the conductive polymer having the sulfonated polyester as a dopant in Example 7. A conductive polymer dispersion of Comparative Example 6 was obtained in the same manner as in Example 1. The ratio of diethyl phosphate to the conductive polymer in the conductive polymer dispersion of Comparative Example 6 was 18%.

Comparative Example 7
1 L of pure water was added to a 2 L separable flask with a stirrer, and 200 g of sodium styrenesulfonate was added thereto. And 1g of ammonium persulfate was added to the solution as an oxidizing agent, and the polymerization reaction 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%. A 3% aqueous solution of polystyrene sulfonic acid was obtained by adjustment.

  About the obtained polystyrene sulfonic acid, the weight average molecular weight estimated by using a gel filtration column and using dextran as a standard was 200,000.

Then, 600 g of the 3% aqueous solution of polystyrene sulfonic acid is put in a stainless steel container having an internal volume of 1 L, and 0.3 g of ferrous sulfate heptahydrate is added, and ethylenedioxythiophene (that is, 3 , 4-ethylenedioxythiophene) was slowly added dropwise. Attach an anode to the vessel, attach two stainless steel plates (3 cm wide x 3 cm long x 2 mm thick) for the cathode in the solution, and stir with a stirring blade made of polytetrafluoroethylene. Electrolytic oxidation polymerization was carried out 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. Then, the excess anion was removed by performing the process and filtration with an anion exchange resin.

  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. Purified water was added to this liquid to adjust the concentration of the content to 3% to obtain 300 g of a conductive polymer dispersion having a concentration of 3%.

  The conductive polymer of Comparative Example 7 was prepared by adding 1.2 g of dibutyl phosphate to the conductive polymer dispersion having a concentration of 3% and adjusting the concentration of the conductive polymer to 1.8%. A dispersion was obtained. The ratio of dibutyl phosphate to the conductive polymer in the conductive polymer dispersion of Comparative Example 7 was 13%.

  Moreover, when the particle size distribution of the conductive polymer in the conductive polymer dispersion of Comparative Example 7 was measured by ELS-Z manufactured by Otsuka Electronics, the average particle size was 120 nm.

Comparative Example 8
Instead of the dispersion of the conductive polymer using the copolymer of styrene sulfonic acid and hydroxyethyl acrylate in Example 1 as a dopant, the dispersion of the conductive polymer using polystyrene sulfonic acid as a dopant in Comparative Example 7 In place of 1.2 g of diethyl phosphite, 1.2 g of dibutyl phosphate was added to the dispersion of the conductive polymer having polystyrene sulfonic acid as a dopant, and the sulfonated polyester in Example 7 was The same operation as in Example 7 was performed except that 1.4 g of dibutyl phosphate was added instead of 1.4 g of diethyl phosphite to the dispersion of the conductive polymer as the dopant. Thus, a conductive polymer dispersion No. 8 was obtained. The ratio of dibutyl phosphate to the conductive polymer in the conductive polymer dispersion of Comparative Example 8 was 18%.

Comparative Example 9
A conductive polymer dispersion of Comparative Example 9 was obtained in the same manner as in Example 13 except that diethyl phosphite was not added. That is, the conductive polymer dispersion of Comparative Example 9 is a conductive polymer dispersion using a copolymer of styrene sulfonic acid and glycidyl methacrylate as a dopant, and phosphorous acid diester is added. It is not.

  When the conductive polymer dispersions of Examples 1 to 17 and Comparative Examples 1 to 9 prepared as described above were stored in an environment of 10 ° C., the conductive polymers of Examples 1 to 17 were The dispersion, the dispersion of the conductive polymer of Comparative Examples 1 to 4 and the dispersion of the conductive polymer of Comparative Example 9 did not gel after 3 months, but the conductivity of Comparative Examples 5 to 8 The dispersion of the conductive polymer was gelled after one month. From the viewpoint of industrial use, conductive polymer dispersions that gel in one month, such as the conductive polymer dispersions of Comparative Examples 5 to 8, are practical enough to withstand industrial use. It must be evaluated if it does not have sex.

  Next, examples of the electrolytic capacitor will be described.

[Evaluation with tantalum solid electrolytic capacitors (1)]
Example 18
In a state where the tantalum sintered body is immersed in a phosphoric acid aqueous solution having a concentration of 1%, 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. Thus, a capacitor element having a set ESR of 50 mΩ or less, a set capacitance of 15 μm 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 of Example 1 and allowed to stand for 5 minutes, then taken out and dried at 150 ° C. for 30 minutes for 4 times to repeat the first layer conductive polymer. A layer was formed.

  Next, the capacitor element having the conductive polymer layer formed thereon was mixed with a 10% phenol sulfonate heptylamine solution (that is, phenol sulfonate heptylamine was mixed in a 1: 1 mass ratio of ethanol and purified water). And then left for 1 minute, taken out, dried at 150 ° C. for 30 minutes, and then immersed in the conductive polymer dispersion of Example 7 above. After leaving for 5 minutes, the operation of taking out and drying at 180 ° C. for 30 minutes was repeated 3 times to form a second conductive polymer layer.

  As described above, the conductive polymer layer containing the phosphite diester formed using the dispersion of the conductive polymer of the present invention containing the phosphite diester is used as an electrolyte layer, and the electrolyte layer is carbon. The tantalum electrolytic capacitor of Example 18 was manufactured by covering with paste and silver paste and then by resin molding.

Example 19
Example 18 is the same as Example 18 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 2 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 19.

Example 20
Example 18 is the same as Example 18 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 3 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 20.

Example 21
Example 18 is the same as Example 18 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 4 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum solid electrolytic capacitor of Example 21.

Example 22
Example 18 is the same as Example 18 except that the conductive polymer dispersion of Example 5 was used instead of the conductive polymer dispersion of Example 1 to form the first conductive polymer layer. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 22,

Example 23
Example 18 is the same as Example 18 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 6 instead of the conductive polymer dispersion of Example 1. Thus, the tantalum electrolytic capacitor of Example 23 was manufactured.

Example 24
Example 18 is the same as Example 18 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 13 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 24.

Example 25
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 8 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 25.

Example 26
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 9 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 26.

Example 27
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 10 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 27.

Example 28
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 11 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 28.

Example 29
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 12 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 29.

Example 30
Example 18 is the same as Example 18 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 17 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 30.

Comparative Example 10
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 1, and the high conductivity of Example 7 was obtained. Except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 2 instead of the molecular dispersion, the same operations as in Example 18 were performed. A tantalum electrolytic capacitor of Comparative Example 10 was produced.

Comparative Example 11
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 3, and the high conductivity of Example 7 was obtained. The same operation as in Example 18 was performed except that the second conductive polymer layer was formed using the conductive polymer dispersion liquid of Comparative Example 4 instead of the molecular dispersion liquid. A tantalum solid electrolytic capacitor of Comparative Example 11 was produced.

Comparative Example 12
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 5, and the high conductivity of Example 7 was obtained. The same operation as in Example 18 was carried out except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 6 instead of the molecular dispersion. A tantalum electrolytic capacitor of Comparative Example 12 was produced.

Comparative Example 13
Instead of the conductive polymer dispersion of Example 1, a conductive polymer layer of Comparative Example 7 was used to form the first conductive polymer layer, and the high conductivity of Example 7 was obtained. The same operation as in Example 18 was carried out except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 8 instead of the molecular dispersion. A tantalum solid electrolytic capacitor of Comparative Example 13 was produced.

  Regarding the tantalum electrolytic capacitors of Examples 18 to 30 and Comparative Examples 10 to 13 manufactured as described above (hereinafter, this “tantalum electrolytic capacitor” may be simply referred to as “capacitor”), ESR, electrostatic Capacitance and leakage current were measured. The results are shown in Table 1 together with the types of conductive polymer dispersions as initial characteristics. In addition, about the kind of dispersion liquid of a conductive polymer, it shows with an Example number or a comparative example number on the relationship on 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 20 samples for each sample, and the numerical values shown in Table 1 are obtained by calculating an average value of the 20 values and rounding off to the second decimal place.

  Further, while applying a rated voltage of 35 V to the capacitors of Examples 18 to 30 and Comparative Examples 10 to 13 after the above characteristic measurement, these capacitors were stored in a thermostatic bath at 125 ° C. for 500 hours, and after the storage, As above, ESR, capacitance and leakage current were measured. The results are shown in Table 2. 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 also shown in Table 2. 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, in the capacitors of Examples 18 to 30, the ESR was 41.4 to 42.6 mΩ, the set ESR of 50 mΩ or less was satisfied, and the capacitance was 15.9 to 16.1 μF. In addition, the set capacitance of 15 μF or more is satisfied, the leakage current is 8.8 to 16.1 μF, the set leakage current of 20 μA or less is satisfied, and compared with the capacitors of Comparative Examples 10 to 13 The current was low. Here, referring to the capacitors of Comparative Examples 10 to 13, the capacitor of Comparative Example 10 has a leakage current of 38.8 μA, which is much larger than the capacitors of Examples 18 to 30, and the Comparative Example. The capacitor No. 11 had an ESR of 48.2 mΩ and satisfied the set ESR, but the capacitance did not satisfy the set value, and the leakage current was larger than the set value. In the capacitors of Comparative Examples 12 to 13, ESR and capacitance did not satisfy the set values.

  Further, as shown in Table 2, the capacitors of Examples 18 to 30 show little increase in ESR, little decrease in capacitance, and little increase in leakage current even after storage at 125 ° C. for 500 hours. , The ESR is 43.2 to 45.6 mΩ, satisfies the set ESR of 50 mΩ or less, the capacitance is 15.4 to 15.6 μF, satisfies the set capacitance of 15 μF or more, and the leakage current is It was 5.9 to 12.1 μA, satisfied a set leakage current of 20 μA or less, and no short circuit occurred.

  In contrast, the capacitor of Comparative Example 10 had an ESR of 77.5 mΩ, approximately doubled after storage at 125 ° C. for 500 hours, and the leakage current also increased significantly, resulting in a short circuit failure. The capacitor of Comparative Example 11 increased in ESR and leakage current due to storage at the above high temperature, decreased in capacitance, ESR, capacitance and leakage current did not satisfy the set values, and short circuit failure occurred. did. The capacitor of Comparative Example 12 also showed an increase in ESR due to the storage at the high temperature, and the capacitor of Comparative Example 13 also increased the ESR considerably significantly by the storage at the high temperature. Thus, all the capacitors of Comparative Examples 10 to 13 were inferior in heat resistance, such as an increase in ESR due to high-temperature storage.

[Evaluation with tantalum solid electrolytic capacitor (2)]
Example 31
In a state where the tantalum sintered body is immersed in a phosphoric acid aqueous solution having a concentration of 1%, chemical conversion treatment is performed by applying a voltage of 60 V, and an oxide film is formed on the surface of the tantalum sintered body to form a dielectric layer. Thus, a capacitor element having a set ESR of 20 mΩ or less, a set capacitance of 100 μF or more, a rated voltage of 25 V, and a set leakage current of 20 μA or less was produced.

  The capacitor element was immersed in the conductive polymer dispersion of Example 1 and allowed to stand for 5 minutes, then taken out and dried at 150 ° C. for 30 minutes twice. A molecular layer was formed.

  Then, 100 g of ethylated ethylenedioxythiophene, 100 g of 2-methylimidazole naphthalene trisulfonate and 60 g of ethanol were added to a beaker with a stirrer having an internal volume of 1 L, and stirred for 1 hour to obtain a monomer solution for producing a conductive polymer. The capacitor element was prepared, immersed in the monomer solution for producing a conductive polymer for 2 minutes, pulled out, and dried at 50 ° C. for 5 minutes. Next, the capacitor element was immersed in an aqueous solution of ammonium persulfate having a concentration of 35% for 2 minutes, pulled out, allowed to stand at room temperature (25 ° C.) for 10 minutes, and then heated at 50 ° C. for 30 minutes for polymerization.

  Thereafter, for washing, the capacitor element was immersed in a mixed solution of pure water and ethanol in a mass ratio of 1: 1 for 30 minutes, pulled out, and dried at 150 ° C. for 30 minutes. This polymerization and subsequent washing steps were repeated twice to form a second conductive polymer layer on the capacitor element.

  Next, the capacitor element having the conductive polymer layer formed thereon was mixed with a 10% phenol sulfonate heptylamine solution (that is, the concentration of phenol sulfonate heptylamine in a 1: 1 mixture of ethanol and purified water). And then left for 1 minute, taken out, dried at 150 ° C. for 30 minutes, and then immersed in the conductive polymer dispersion of Example 9 above. After leaving for 5 minutes, the operation of taking out and drying at 180 ° C. for 30 minutes was repeated 3 times to form a third conductive polymer layer.

  As described above, the first layer and the third layer in the conductive polymer layer having the three-layer structure are formed by using the conductive polymer dispersion of the present invention containing the phosphorous acid diester. A conductive polymer layer having a three-layer structure composed of a conductive polymer layer containing an acid diester is used as an electrolyte layer, and the electrolyte layer is covered with a carbon paste and a silver paste, and packaged by resin molding to provide an exterior. A tantalum electrolytic capacitor was manufactured.

Example 32
Example 31 is the same as Example 31 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 2 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 32.

Example 33
Example 31 is the same as Example 31 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 3 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 33.

Example 34
Example 31 is the same as Example 31 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 4 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 34.

Example 35
Example 31 is the same as Example 31 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 5 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 35.

Example 36
Example 34 is the same as Example 34 except that the first conductive polymer layer was formed using the conductive polymer dispersion of Example 6 instead of the conductive polymer dispersion of Example 1. The same operation was performed to manufacture the tantalum electrolytic capacitor of Example 36.

Comparative Example 14
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 1, and the conductivity high of Example 9 was obtained. The same operation as in Example 31 was performed except that the third conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 2 instead of the molecular dispersion. A tantalum solid electrolytic capacitor of Comparative Example 14 was produced.

Comparative Example 15
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 3, and the high conductivity of Example 9 was obtained. The same operation as in Example 31 was performed except that the third conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 4 instead of the molecular dispersion. A tantalum solid electrolytic capacitor of Comparative Example 15 was produced.

Comparative Example 16
Instead of the conductive polymer dispersion of Example 1, the first conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 5, and the high conductivity of Example 9 was obtained. The same operation as in Example 31 was performed except that the third conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 6 instead of the molecular dispersion. A tantalum solid electrolytic capacitor of Comparative Example 16 was produced.

Comparative Example 17
Instead of the conductive polymer dispersion of Example 1, a conductive polymer layer of Comparative Example 7 was used to form the first conductive polymer layer, and the high conductivity of Example 9 was obtained. The same operation as in Example 31 was performed except that the third conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 8 instead of the molecular dispersion. A tantalum solid electrolytic capacitor of Comparative Example 17 was produced.

  For the tantalum electrolytic capacitors of Examples 31 to 36 and Comparative Examples 14 to 17 manufactured as described above, ESR, capacitance, and leakage current were measured in the same manner as described above. However, since the rated voltage of these capacitors is 25V, the leakage current was measured by applying 25V to the capacitors. The results are shown in Table 3 as initial characteristics in the same manner as in Table 1.

  While applying the rated voltage of 25 V to the capacitors of Examples 31 to 36 and Comparative Examples 14 to 17 after the above characteristic measurement, these capacitors were stored at 125 ° C. for 500 hours, and after the storage, ESR, Capacitance and leakage current were measured, and occurrence of short-circuit failure was examined. However, also in this case, the applied voltage was 25V. The results are shown in Table 4 in the same manner as in Table 2.

  As shown in Table 3, the capacitors of Examples 31 to 36 had an ESR of 15.3 to 15.9 mΩ, satisfied a set ESR of 20 mΩ or less, and had a capacitance of 114.4 to 115.4 μF. Thus, the set capacitance of 100 μF or more is satisfied, the leakage current is 11.4 to 14.2 μA, the set leakage current of 20 μA or less is satisfied, and the leakage current is smaller than the capacitors of Comparative Examples 14 to 17. And the ESR was low.

  When the capacitors of Comparative Examples 14 to 17 are mentioned, the capacitor of Comparative Example 14 and the capacitor of Comparative Example 15 do not satisfy the set values of ESR and leakage current, and the capacitor of Comparative Example 16 has ESR and electrostatic capacitance. The capacitance did not satisfy the set value, and the capacitor of Comparative Example 17 had the ESR and leakage current not satisfying the set value.

  In addition, as shown in Table 4, the capacitors of Examples 31 to 36 have little increase in ESR, decrease in capacitance, and increase in leakage current due to storage at high temperature, and after storage at 125 ° C. for 500 hours. The ESR is 19.1 to 19.8 mΩ, satisfies the set ESR of 20 mΩ or less, the capacitance is 100.0 to 110.1 μF, satisfies the set capacitance of 100 μF or more, and the leakage current is It was 6.4 to 8.7 μA, satisfied a set leakage current of 20 μA or less, and no short circuit occurred.

  In contrast, the capacitor of Comparative Example 14 had a large increase in leakage current due to storage at high temperature and a large increase in ESR, and the heat resistance was inferior to the capacitors of Examples 31 to 36.

  In addition, the capacitors of Comparative Examples 15 to 17 also had a large increase in ESR due to storage at high temperatures, and the heat resistance was inferior to the capacitors of Examples 31 to 36.

[Evaluation with multilayer aluminum electrolytic capacitor (1)]
Example 37
In Example 37 and Examples 38 to 43 that follow, a so-called multilayer aluminum electrolytic capacitor is manufactured and its characteristics are evaluated. Hereinafter, the production of the multilayer aluminum electrolytic capacitor of Example 37 will be specifically described.

  Fluorine resin with a width of 1 mm in the lateral direction of the above-mentioned aluminum etched foil so that it is divided into a portion of 5 mm from one end in the vertical direction and a portion of 4 mm from the other end of the aluminum etched foil having a length of 10 mm × 3.3 mm The paint was applied and cured. Next, a silver wire was attached as an anode to a portion 2 mm from the one end in a portion 5 mm from one end in the longitudinal direction of the foil. Further, a 4 mm portion (4 mm × 3.3 mm) from the other longitudinal end of the foil is immersed in an aqueous solution of ammonium adipate having a concentration of 10%, and a chemical conversion treatment is performed by applying a voltage of 25 V to obtain aluminum. A capacitor element having an ESR of 20 mΩ or less, a set capacitance of 30 μF or more, a rated voltage of 12 V, and a set leakage current of 10 μF or less was formed.

  Then, 100 g of ethylated ethylenedioxythiophene, 100 g of 2-methylimidazole naphthalenetrisulfonate and 60 g of ethanol are added to a beaker with a stirrer having an internal volume of 1 L, and stirred for 1 hour to prepare a monomer solution for producing a conductive polymer. The capacitor element was immersed in the conductive polymer manufacturing monomer solution for 2 minutes, pulled out, and dried at 50 ° C. for 5 minutes. Next, the capacitor element was immersed in an aqueous solution of ammonium persulfate having a concentration of 35% for 2 minutes, pulled out, allowed to stand at room temperature (25 ° C.) for 10 minutes, and then heated at 50 ° C. for 30 minutes for polymerization.

  Thereafter, for washing, the capacitor element was immersed in a mixed solution of pure water and ethanol in a mass ratio of 1: 1 for 30 minutes, pulled out, and dried at 150 ° C. for 30 minutes. This polymerization and washing steps were repeated four times to form a first conductive polymer layer on the capacitor element.

  Next, the capacitor element having the conductive polymer layer formed thereon is mixed with a 10% solution of hexylamine phenolsulfonate (that is, the concentration of hexylamine phenolsulfonate in a 1: 1 mixture of ethanol and purified water). And then left for 1 minute, taken out, dried at 150 ° C. for 30 minutes, and then immersed in the conductive polymer dispersion of Example 7 above. After leaving for 5 minutes, the operation of taking out and drying at 180 ° C. for 30 minutes was repeated twice to form a second conductive polymer layer.

  As described above, the second layer in the two-layered conductive polymer layer is formed using the conductive polymer dispersion containing the phosphite diester of the present invention. A two-layered conductive polymer layer composed of molecular layers was used as an electrolyte layer, and this electrolyte layer was covered with a carbon paste and a silver paste and packaged with a resin to produce a multilayer aluminum electrolytic capacitor of Example 37.

Example 38
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 8 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a laminated aluminum electrolytic capacitor of Example 38.

Example 39
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 9 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a multilayer aluminum electrolytic capacitor of Example 39.

Example 40
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 10 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the laminated aluminum electrolytic capacitor of Example 40.

Example 41
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 11 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture the multilayer aluminum electrolytic capacitor of Example 41.

Example 42
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Example 12 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a laminated aluminum electrolytic capacitor of Example 42.

Example 43
The same procedure as in Example 37 was followed, except that the conductive polymer dispersion of Example 17 was used instead of the conductive polymer dispersion of Example 7, and the laminated type of Example 43 was used. An aluminum electrolytic capacitor was manufactured.

Comparative Example 18
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 2 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a laminated aluminum electrolytic capacitor of Comparative Example 18.

Comparative Example 19
The same operation as in Example 37 was performed except that the second conductive polymer layer was formed using the conductive dispersion liquid of Comparative Example 4 instead of the conductive dispersion liquid of Example 7. As a result, a laminated aluminum electrolytic capacitor of Comparative Example 19 was produced.

Comparative Example 20
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 6 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a laminated aluminum electrolytic capacitor of Comparative Example 20.

Comparative Example 21
Example 37 is the same as Example 37 except that the second conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 8 instead of the conductive polymer dispersion of Example 7. The same operation was performed to manufacture a laminated aluminum electrolytic capacitor of Comparative Example 21.

  For the laminated aluminum electrolytic capacitors of Examples 37 to 43 and Comparative Examples 18 to 21 manufactured as described above (hereinafter, this may be simply referred to as “capacitor”), ESR and capacitance are the same as described above. And the leakage current was measured. However, since the rated voltage of these capacitors is 12V, the leakage current was measured by applying 12V to the capacitors. The results are shown in Table 5 in the same manner as in Table 1 as initial characteristics.

  Moreover, while applying 12V of the rated voltage to the capacitors after the above characteristic measurement, these capacitors are stored at 125 ° C. for 500 hours, and the ESR, capacitance and leakage current after the storage are measured in the same manner as described above, In addition, the occurrence of short-circuit defects was examined. In this case, however, the applied voltage was 12V. The results are shown in Table 6 in the same manner as in Table 2.

  As shown in Table 5, the capacitors of Examples 37 to 42 had an ESR of 15.7 to 16.3 mΩ, satisfied a set ESR of 20 mΩ or less, and had a capacitance of 34.2 to 34.6 μF. Thus, the set capacitance of 30 μF or more is satisfied, the leakage current is 6.5 to 8.8 μA, the set leakage current of 10 μA or less is satisfied, and the ESR is lower than the capacitors of Comparative Examples 18 to 21, And there was little leakage current.

  In addition, as shown in Table 6, the capacitors of Examples 37 to 43 have little increase in ESR and leakage current due to storage at high temperature, and little decrease in capacitance, even after storage at 125 ° C. for 500 hours. , The ESR is 18.3 to 19.8 mΩ, satisfies the set ESR of 20 mΩ or less, the capacitance is 31.1 to 31.6 μF, satisfies the set capacitance of 30 μF or more, and the leakage current is 1.1 to 4.2 μA, a set leakage current of 10 μA or less was satisfied, and no short circuit occurred.

  On the other hand, the capacitor of Comparative Example 18 shows a decrease in characteristics during high-temperature storage, such as a large increase in ESR and leakage current, a decrease in capacitance, and short circuit failure after storage at 125 ° C. for 500 hours. The heat resistance was inferior.

  Further, the capacitor of Comparative Example 19 also has a characteristic deterioration due to storage at high temperature, and after storage at 125 ° C. for 500 hours, the increase in ESR and the increase in leakage current are large, the capacitance is also reduced, and short circuit failure is also caused. It was inferior in heat resistance.

  The capacitors of Comparative Examples 20 to 21 also had a large increase in ESR and poor heat resistance due to storage at high temperatures.

[Evaluation with a wound aluminum electrolytic capacitor (1)]
Example 44
In Example 44 and Examples 45 to 46 subsequent thereto, a so-called wound aluminum electrolytic capacitor is manufactured and its characteristics are evaluated. Hereinafter, the production of the wound aluminum electrolytic capacitor of Example 44 will be specifically described.

  The surface of the aluminum foil is made porous by etching, and the aluminum foil after the etching is immersed in a 10% ammonium adipate aqueous solution, and a voltage of 100 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 50 μF or more, a rated voltage of 50 V, and a set leakage current of 20 μA or less was produced.

  The capacitor element was immersed in the conductive polymer dispersion of Example 14 prepared as described above, allowed to stand for 5 minutes, then taken out and dried at 180 ° C. for 30 minutes twice. The sample was immersed in a solution in which 3% of hydroxybenzoic acid and 1% of nitrobenzoic acid were dissolved, allowed to stand for 5 minutes, then taken out and dried at 180 ° C. for 30 minutes to form a conductive polymer layer.

  As described above, a conductive polymer layer containing a phosphite diester formed using a dispersion of a conductive polymer containing a phosphite diester of the present invention is used as an electrolyte layer, and the electrolyte layer is packaged with an exterior material. Thus, a wound aluminum electrolytic capacitor of Example 44 was produced.

Example 45
The same operation as in Example 44 was performed except that the conductive polymer layer was formed using the conductive polymer dispersion of Example 15 instead of the conductive polymer dispersion of Example 14. Thus, a wound aluminum electrolytic capacitor of Example 45 was produced.

Example 46
The same operation as in Example 44 was performed except that the conductive polymer layer was formed using the conductive polymer dispersion of Example 16 instead of the conductive polymer dispersion of Example 14. Thus, a wound aluminum electrolytic capacitor of Example 46 was produced.

Comparative Example 22
The same operation as in Example 44 was performed except that the conductive polymer layer was formed using the conductive polymer dispersion of Comparative Example 9 instead of the conductive polymer dispersion of Example 14. Thus, a wound aluminum electrolytic capacitor of Comparative Example 22 was produced.

  Regarding the wound aluminum electrolytic capacitors of Examples 44 to 46 and Comparative Example 22 manufactured as described above (hereinafter, this may be simply referred to as “capacitor”), ESR, Capacitance and leakage current were measured. However, since the rated voltage of these capacitors was 50V, the leakage current was measured by applying 50V to the capacitors. The results are shown in Table 7 as initial characteristics in the same manner as in Table 1.

  Further, while applying a rated voltage of 50 V to the capacitors after the above characteristic measurement, the capacitors were stored at 125 ° C. for 1500 hours, and the ESR, capacitance, and leakage current after the storage were measured in the same manner as described above. The results are shown in Table 8 in the same manner as in Table 2.

  As shown in Table 7, the capacitors of Examples 44 to 46 have an ESR of 24.5 to 25.5 mΩ, satisfy a set ESR of 30 mΩ or less, and have a capacitance of 56.5 to 56.7 μF. In addition, the set capacitance of 50 μF or more was satisfied, the leakage current was 8.4 to 13.5 μA, the set leakage current of 20 μA or less was satisfied, and the leakage current was less than that of the capacitor of Comparative Example 22.

  Further, as shown in Table 8, the capacitors of Examples 44 to 46 have little increase in ESR, decrease in capacitance, and increase in leakage current due to storage at high temperature (rather, it is a decrease). Even after storage at 1500 ° C., the ESR is 27.1 to 28.2 mΩ, satisfies the set ESR of 30 mΩ or less, the capacitance is 52.2 to 52.3 μF, and the set electrostatic capacity is 50 μF or more. The capacity was satisfied, the leakage current was 0.9 to 6.4 μA, and the set leakage current of 20 μA or less was satisfied.

  On the other hand, the capacitor of Comparative Example 22 has a larger increase in leakage current and increased ESR due to storage at high temperature than the capacitors of Examples 44 to 46, and after storage at 125 ° C. for 1500 hours, ESR Was larger than the set value of 30 mΩ or less, and the leakage current increased to 22.9 μA, which did not satisfy the set value of 20 μA or less. As described above, the capacitor of Comparative Example 22 was inferior in heat resistance as compared with the capacitors of Examples 44 to 46.

Claims (4)

A conductive polymer dispersion for producing an electrolytic capacitor, comprising at least a conductive polymer, a phosphite diester, and a dispersion medium.
However, the conductive polymer is synthesized using at least one polymer anion selected from the group consisting of sulfonated polyester, phenolsulfonic acid novolak resin, and a copolymer of styrenesulfonic acid and a non-sulfonic acid monomer as a dopant. der thing was is, the phosphorous acid diester is at least one selected from phosphorous acid dialkyl ester, the group consisting of dibenzyl phosphite and diphenyl phosphite alkyl group having 1 to 8 carbon atoms. Non acid-based monomer, acrylic acid ester Te Le, electrolytic capacitors produced according to claim 1, wherein at least one selected from methacrylic acid esters and unsaturated hydrocarbons containing alkoxysilane compound or the group consisting of the hydrolyzate Conductive polymer dispersion. An electrolytic capacitor having an electrolyte layer on a dielectric layer of a capacitor element, wherein the electrolyte layer contains at least a conductive polymer and a phosphite diester.
However, the conductive polymer is synthesized using at least one polymer anion selected from the group consisting of sulfonated polyester, phenolsulfonic acid novolak resin, and a copolymer of styrenesulfonic acid and a non-sulfonic acid monomer as a dopant. der thing was is, the phosphorous acid diester is at least one selected from phosphorous acid dialkyl ester, the group consisting of dibenzyl phosphite and diphenyl phosphite alkyl group having 1 to 8 carbon atoms. Non acid-based monomer, an electrolytic capacitor according to claim 3, wherein at least one selected from the group consisting of acrylic acid ester Te Le, methacrylic acid esters and unsaturated hydrocarbons containing alkoxysilane compound or a hydrolyzate thereof.