WO2020196473A1

WO2020196473A1 - Electroconductive polymer composition

Info

Publication number: WO2020196473A1
Application number: PCT/JP2020/012879
Authority: WO
Inventors: 豪宮本; 岡本　秀二
Original assignee: 綜研化学株式会社
Priority date: 2019-03-26
Filing date: 2020-03-24
Publication date: 2020-10-01
Also published as: TW202100654A; JP2022078370A

Abstract

Provided is an electroconductive polymer composition capable of forming a film of excellent electroconductivity, moist-heat resistance and heat resistance. This electroconductive polymer composition contains a solvent, an π-conjugated electroconductive polymer and an additive; the electroconductive polymer has at least one structural unit represented by general formula (1) or (2); and the additive includes an organic sulfonic acid and an aromatic staking promoter that promotes stacking of the electroconductive polymer.

Description

Conductive polymer composition

The present invention relates to a conductive polymer composition.

One of the uses of conductive polymers is the solid electrolyte of capacitors. It is required to be used in a harsher environment, and reliability in a high heat and high humidity environment is required.

Patent Document 1 discloses a capacitor using a PEDOT / PSS film as a solid electrolyte.

Japanese Unexamined Patent Publication No. 2018-22727

However, the conductive polymer typified by PEDOT / PSS undergoes a structural change under moist heat conditions, resulting in a decrease in conductivity, peeling of the coating film from the substrate, cracking of the coating film, and the like. There was a problem such as a change of state.

The present invention has been made in view of such circumstances, and provides a conductive polymer composition capable of forming a coating film having excellent conductivity, moisture heat resistance, and heat resistance.

According to the present invention, the conductive polymer composition contains a solvent, a π-conjugated conductive polymer, and an additive, and the conductive polymer is represented by the general formula (1) or (2). The additive is provided by a conductive polymer composition containing at least one of the constituent units to be formed, an aromatic stacking accelerator that promotes stacking of the conductive polymer, and an organic sulfonic acid. Will be done.

As a result of diligent studies by the present inventor, it was found that the coating film formed by using the composition having the above composition is excellent in conductivity, moisture heat resistance, and heat resistance, and the present invention has been completed. ..

Hereinafter, embodiments of the present invention will be described in detail.

1. 1. Conductive Polymer Composition The conductive polymer composition of one embodiment of the present invention contains a solvent, a π-conjugated conductive polymer (hereinafter, “conductive polymer”), and an additive. Hereinafter, each component will be described in detail.

1-2. Solvent The solvent is not particularly limited as long as it can dissolve or disperse the conductive polymer, and preferably contains an organic solvent. Examples of the organic solvent include alcohol solvents such as methanol, ethanol, isopropyl alcohol and butanol, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, propylene glycol methyl ether and propylene glycol ethyl ether. Glycol-based solvents, lactic acid-based solvents such as methyl lactate and ethyl lactate, toluene, ethyl acetate, propylene carbonate, γ-butyrolactone, methyl ethyl ketone, toluene, isopropyl alcohol, ethylene glycol, dimethyl sulfoxide, methanol, benzyl alcohol and the like. , Propylene carbonate, γ-butyrolactone, methyl ethyl ketone, toluene, isopropyl alcohol, ethylene glycol, dimethyl sulfoxide, methanol, benzyl alcohol and the like are particularly preferable. The organic solvent may be used in combination of a plurality of solvents, and may be the same as or different from the solvent used for synthesizing the conductive polymer.

In order to disperse and stabilize the conductive polymer in water, excess sulfonic acid that does not contribute to doping is required, but when the conductive polymer composition contains an organic solvent, the conductivity is high even if the amount of excess sulfonic acid is small. It is possible to stably dissolve or disperse the molecule in an organic solvent.

The non-volatile content of the conductive polymer composition excluding the organic solvent is not particularly limited, but is, for example, 0.1% by mass or more and 20.0% by mass or less. Specifically, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 10.0, 15.0, 20.0 mass% It may be within the range between any two of the numerical values exemplified here.

The solvent of the conductive polymer composition may contain water in addition to the above organic solvent, but from the viewpoint of substrate adhesion, the water content is preferably 50% or less with respect to the solvent, and more preferably 10% or less. preferable.

1-2. π-Conjugated Conductive Polymer The π-conjugated conductive polymer of the present invention is composed of a π-conjugated polymer doped with a dopant.

Examples of the π-conjugated polymer include any polymer having a π-conjugated system, for example, a polymer containing aniline, pyrrole, thiophene or a derivative thereof in the skeleton, and a polymer containing thiophene or a derivative thereof in the skeleton. Polymers are preferred. In this case, this is because the environmental stability against temperature other than humidity and oxygen in the doped state and the undoped state is excellent.

Examples of the dopant include any compound capable of imparting conductivity to the π-conjugated polymer, and may be either a polymer dopant or a low molecular weight dopant. Examples of the polymer dopant include polyvalent acids such as polystyrene sulfonic acid (PSS). As the polymer dopant, those that receive electrons from a π-conjugated polymer to become a polyanion are preferable. Low molecular weight dopants include vinyl sulfonic acid, p-toluene sulfonic acid, 2-naphthalene sulfonic acid, 1-naphthalene sulfonic acid, dodecyl sulfonic acid, dodecylbenzene sulfonic acid, di (2-ethylhexyl) sulfosuccinic acid, tetrafluoroboric acid. , Trifluoroacetic acid, hexafluorophosphate, monovalent acids such as trifluoromethanesulfonimide, or alkali metal salts thereof.

As the low molecular weight dopant, one that receives electrons from a π-conjugated polymer to become a monoanion is preferable, a monoanion having a sulfo group is preferable, and a monoanion having a structure in which an alkyl chain and a sulfo group are bonded is more preferable. Since it is easy to improve the conductivity of the conductive polymer by using a dopant that becomes a monoanion, it is preferable to use a dopant that becomes a monoanion.

The conductive polymer preferably has at least one of the structural units represented by the general formula (1) or (2). Π conjugated polymer contained in the conductive polymer, dispersibility in solvent is enhanced by having R ^1.

In the general formulas (1) and (2), R ¹ may have a substituent, respectively, an alkyl group having 1 or more and 12 or less carbon atoms, an alkyl ether group having 1 or more and 12 or less carbon atoms, and 1 carbon number. Represents an alkoxy group having 12 or more carbon atoms, an alkylene oxide group having 1 to 12 carbon atoms, an aromatic group, or a heterocyclic group. R ² is an oxygen atom or a sulfur atom, respectively, and R ³ is an alkyl group having 1 to 12 carbon atoms and an alkyl having 1 to 12 carbon atoms, which may have a hydrogen atom and a substituent, respectively. It represents an ether group, an alkoxy group having 1 to 12 carbon atoms, an alkylene oxide group having 1 to 12 carbon atoms, an aromatic group, or a heterocyclic group. A ⁻ is a monoanion derived from a dopant. n is 2 or more and 300 or less.

The alkyl group having 1 or more and 12 or less carbon atoms may be linear, branched, cyclic or the like, and may be, for example, 1 or more and 8 or less carbon atoms, 1 or more and 6 or less carbon atoms, 1 or more and 4 or less carbon atoms, or the like. May be present, specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, cyclopentyl group, cyclohexyl group, bornyl group, isobornyl group, dicyclopentanyl. Examples include a group and an adamantyl group.

The alkyl ether group having 1 or more and 12 or less carbon atoms may be linear, branched, cyclic or the like, and may be, for example, 1 or more and 8 or less carbon atoms, 1 or more and 6 or less carbon atoms, 1 or more and 4 or less carbon atoms, or the like. Is.

The alkoxy group having 1 or more and 12 or less carbon atoms may be linear, branched, cyclic or the like, and may be, for example, 1 or more and 8 or less carbon atoms, 1 or more and 6 or less carbon atoms, 1 or more and 4 or less carbon atoms, or the like. Is.

Examples of the alkylene oxide group having 1 or more and 12 or less carbon atoms include 1 or more and 8 or less carbon atoms, 1 or more and 6 or less carbon atoms, and 1 or more and 4 or less carbon atoms.

Examples of the aromatic group include various condensed ring groups in addition to the phenyl group and the benzyl group. The fused ring groups include naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthalene ring, triphenylene ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, pentacene ring, perylene ring, and the like. Examples include a pentaphene ring, a picene ring, and a pyrenethan ring.

Examples of the heterocyclic group include a silol ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an oxaziazole ring, a triazole ring, an imidazole ring, and a pyrazole. Ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (any of the carbon atoms constituting the carbazole ring) One or more of which are replaced by nitrogen atoms), dibenzosilol ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or ring in which any one or more of the carbon atoms constituting the dibenzofuran ring are replaced by nitrogen atom, Bendifuran ring, benzodithiophene ring, aclysine ring, benzoquinoline ring, phenazine ring, phenanthridin ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, fe. Nantrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring, thianthene ring, phenoxatiin ring , Dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietan ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring Ring, tetrahydrothiophene ring, sulforane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholin ring, tetrahydropyran ring, 1,3-dioxane Ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholin ring, thiomorpholin-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane ring, phenoxazine ring, Examples thereof include a monovalent group derived from a phenothiazine ring, an oxanthene ring, a thioxanthene ring, and a phenoxatiin ring.

Examples of the substituent that R ¹ or R ³ may have include an alkyl group having 1 to 12 carbon atoms, the alkyl ether group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. An alkylene oxide group having 1 to 12 carbon atoms, an aromatic group, a hydroxy group, a carboxyl group, a halogen such as fluorine, chlorine, bromine, iodine, an aldehyde group, an amino group, a cycloalkyl group having 3 to 8 carbon atoms, etc. The hydroxy group and the carboxyl group are preferable.

The number of structural units (1) and (2) contained in the conductive polymer is not particularly limited, but is preferably 2 or more and 300 or less. Specifically, for example, it is 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200 or 300, and is within the range between any two of the numerical values exemplified here. It may be.

The content ratios of the structural units (1) and (2) contained in the conductive polymer can be adjusted by the ratio of the addition amount of the thiophene derivative represented by the general formula (3) and the aldehyde. The molar ratio of the amount of the thiophene derivative to the aldehyde added (thiophene derivative / aldehyde) is, for example, 1/1, 2/1, 3/1, 4/1, 5/1, etc., and any two of these values Although it may be within the range between them, the ratio of 1/1 to 4/1 is preferable, and the ratio of 1/1 to 2/1 is more preferable from the viewpoint of the balance between solubility and conductivity.

In the general formula (3), R ² and R ³ are defined in the same manner as R ² and R ^{3 in} the general formulas (1) and (2), respectively.

The method for synthesizing the conductive polymer is not particularly limited, but for example, it can be obtained by adding a dopant and an oxidizing agent to a thiophene derivative and an aldehyde and polymerizing by heating and stirring in a solvent under an inert gas atmosphere. Can be done. Further, a decomposition accelerator of an oxidizing agent may be added.

The molar ratio of the dopant to the thiophene derivative (dopant / thiophene derivative) is, for example, 0.01 to 0.5, preferably 0.1 to 0.5. Specifically, the molar ratio is, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, and any two of the numerical values exemplified here. It may be within the range between. If this molar ratio is too small, the conductivity of the conductive polymer may become too low.

The oxidizing agent is not particularly limited as long as it is an oxidizing agent in which the polymerization reaction proceeds, and it may be ammonium peroxodisulfate, potassium peroxodisulfate, sodium peroxodisulfate, iron (III) chloride, iron (III) sulfate, or hydroxide. Iron (III), Iron Fluoroboric Acid (III), Iron Hexafluorophosphate (III), Copper Sulfate (II), Copper Chloride (II), Copper Fluoroboric Acid (II), Copper Hexafluorophosphate ( II) and organic peroxides such as ammonium oxodisulfate, benzoyl peroxide and lauroyl peroxide can be mentioned.

The solvent is not particularly limited as long as it is a solvent in which the reaction between the heterocyclic compound and the aldehyde derivative proceeds, and it may be γ-butyrolactone, propylene carbonate, ethylene carbonate, acetonitrile, tert-butylmethyl ether, ethyl acetate, benzene, heptane. , Water, methanol, ethanol, isopropyl alcohol, butanol and other alcohol solvents, acetone, methyl ethyl ketone, methyl isobutyl ketone and other ketone solvents, methyl cellosolve, ethyl cellosolve, propylene glycol methyl ether, propylene glycol ethyl ether and other glycol solvents. , Lactic acid-based solvents such as methyl lactate and ethyl lactate. From the viewpoint of the efficiency of the oxidizing agent, an aprotic solvent is preferable.

1-3. Additives Additives contain an aromatic stacking accelerator (hereinafter, “stacking accelerator”) that promotes stacking of the above-mentioned conductive polymer, and an organic sulfonic acid.

When the conductive polymer composition contains such an additive, the conductivity, moisture heat resistance, and heat resistance of the coating film to be formed are improved.

The above conductive polymer has a relatively low flatness, so stacking is unlikely to occur. Therefore, it is difficult for electrons to be transmitted across the conductive polymers, and it is difficult for the conductivity to increase. Further, since stacking is unlikely to occur, the bonding force between the conductive polymers is relatively small, and the moisture resistance and heat resistance are difficult to be sufficiently increased.

<Organic sulfonic acid>
The organic sulfonic acid in the additive has a function of increasing the cationic property of the conductive polymer and promoting the stacking of the conductive polymer. Therefore, the addition of the organic sulfonic acid improves the conductivity of the coating film. On the other hand, since the organic sulfonic acid has a high affinity with water, the addition of the organic sulfonic acid makes it easier for water to penetrate into the coating film, and the moisture and heat resistance of the coating film is lowered.

Water easily penetrates into the coating film because the stacking of the conductive polymers is insufficient and there are gaps between the conductive polymers. Therefore, in the present invention, the stacking accelerator is added to promote the stacking of the conductive polymer, thereby reducing the gap. Therefore, according to the present invention, moist heat resistance is improved. Further, by adding the stacking accelerator, the bonding force between the conductive polymers is increased, so that the heat resistance is improved, and the conductive paths of electrons between the conductive polymers are increased, so that the conductivity is improved.

Examples of the organic sulfonic acid include p-toluenesulfonic acid, naphthalenesulfonic acid (eg 2-naphthalenesulfonic acid, 1-naphthalenesulfonic acid), dodecylsulfonic acid, dodecylbenzenesulfonic acid and the like.

The organic sulfonic acid may be present in the conductive polymer composition in a free state, or may be present in a state of being bound to a stacking accelerator (eg, ionic bond).

The conductive polymer composition preferably contains 0.5 to 30 parts by mass of organic sulfonic acid with respect to 100 parts by mass of the conductive polymer, and preferably contains 1 to 15 parts by mass. This is because if the amount of organic sulfonic acid is too small, the stacking promoting effect may not be sufficient, and if it is too large, the moisture and heat resistance may be lowered. Specifically, the content of the organic sulfonic acid is, for example, 0.5, 1, 2, 5, 10, 15, 20, 25, 30 parts by mass, and is between any two of the numerical values exemplified here. It may be within the range.

<Stacking accelerator>
The stacking accelerator is preferably a multi-ring compound having a plurality of aromatic rings constituting the π-conjugated system, or a precursor thereof. The plurality of aromatic rings may form a π-conjugated system by being connected to each other by a single or double bond, or may form a fused ring. The number of aromatic rings constituting the π-conjugated system is preferably 2 to 5, and more preferably 2 to 3.

Such a compound has high flatness and easily penetrates into the gaps between the conductive polymers to promote stacking of the conductive polymers.

The precursor of the polycyclic compound is a compound that causes the polycyclic compound by the reaction, for example, a reactive monomer. Stacking of conductive polymers is promoted by the reaction of precursors of the multi-ring compound to produce the multi-ring compound. As the reactive monomer, those in which the polymerization reaction proceeds in the heat treatment step when the coating film is formed using the conductive polymer composition are preferable. An oxidizing agent for accelerating this polymerization reaction may be added to the conductive polymer composition. The addition of the oxidizing agent suppresses the residue of the precursor of the polycyclic compound. Therefore, the bleed-out of the precursor of the plurality of ring compounds is suppressed in a moist heat environment, and the moist heat resistance is improved. Further, the addition of the oxidizing agent increases the amount of the plural ring compound produced, so that the conductivity is improved. The oxidizing agent is preferably added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the conductive polymer. Specifically, the amount of the oxidizing agent added is, for example, 1, 5, 10, 15, and 20 parts by mass, and may be within the range between any two of the numerical values exemplified here. As the oxidizing agent, those described above can be used in the description of oxidative polymerization of the conductive polymer.

The molecular weight of the compound constituting the stacking accelerator is, for example, 100 to 2000, preferably 100 to 1500, and preferably 100 to 1000. If the molecular weight is too large, it may be difficult to enter the gap between the conductive polymers. Specifically, the molecular weight is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000. Yes, it may be within the range between any two of the numerical values exemplified here.

The number of atoms of the compound constituting the stacking accelerator is, for example, 10 to 200, and specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130. , 140, 150, 160, 170, 180, 190, 200, and may be within the range between any two of the numerical values exemplified here.

The conductive polymer composition preferably contains 1 to 40 parts by mass of the stacking accelerator with respect to 100 parts by mass of the conductive polymer, and preferably contains 2 to 25 parts by mass. This is because if the amount of the stacking accelerator is too small, the stacking promoting effect may not be sufficient, and if it is too large, the conductivity of the coating film may decrease due to surface bleeding. Specifically, the content of the stacking accelerator is, for example, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40 parts by mass, and is between any two of the numerical values exemplified here. It may be within the range.

The stacking accelerator preferably contains an oxygen atom or a nitrogen atom. In this case, the affinity between the stacking accelerator and the conductive polymer is increased, and the stacking promoting effect is enhanced.

The stacking accelerator preferably does not contain a nitrogen atom having an unshared electron pair. This is because the compound having a nitrogen atom having an unshared electron pair becomes a base and reduces the stacking promoting effect of the organic sulfonic acid. Examples of such compounds include amine compounds, and examples of amine compounds include primary amines, secondary amines, tertiary amines, aromatic amines, and heterocyclic amines.

The stacking accelerator preferably contains at least one selected from the group consisting of polythiophene, thiophene derivative, dithiol derivative, naphthalene derivative, and anthracene derivative. This is because such compounds are particularly effective in promoting stacking.

-Polythiophene Polythiophene is, for example, a polymer of a thiophene derivative represented by the above general formula (3). The degree of polymerization is, for example, 2 to 50, preferably 2 to 30. If the degree of polymerization is too large, it may be difficult to enter the gaps between the conductive polymers. The polythiophene is preferably doped with a dopant (preferably an organic sulfonic acid).

-Thiophene derivative A thiophene derivative is a compound having a thiophene skeleton. The thiophene derivative may be a polycyclic compound or a precursor thereof. Examples of the thiophene derivative which is a multicyclic compound include dibenzothiophene, benzothiophene, benzo [b] thiophene, 2,2'-bithiophene, 4H-cyclopenta [2,1-b3,4-b] thiophene, benzodithiophene and the like. Can be mentioned. Examples of the thiophene derivative as a precursor include a thiophene derivative represented by the above general formula (3) (eg, EDOT), 4-ethylenedioxythiophene, 3,4-ethylenedithiothiophene, and 3,4- (2,2). -Dimethylpropylenedioxy) Thiophene, 2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-ylmethanol and the like can be mentioned. Benzothiophene is a compound having a condensed ring, but thiophenes can be linked to each other by polymerization. When the thiophene derivative is a precursor of a polycyclic compound, the additive preferably contains an oxidizing agent.

-Dithiol derivative The dithiol derivative is a compound having a dithiol group, preferably a compound having an aromatic ring having a dithiol group, and more preferably two aromatic rings having a dithiol group in a single or double bond with each other. It is a compound in which a π-conjugated system is formed by being linked. Examples of dithiol derivatives include tetrathiafulvalene, bis (ethylenedithio) tetrathiafulvalene, 4,5-ethylenedithio-1,3-dithiol-2-thione, and 4,5-bis (methylthio) -1,3-dithiol-2-. On, 4,4-dimethyl-5,5-diphenyltetrathiafulvalene and the like can be mentioned.

-Naphthalene derivative A naphthalene derivative is a compound having a naphthalene skeleton. The naphthalene derivative is preferably a compound having a polar functional group. In this case, the affinity between the naphthalene derivative and the conductive polymer is improved, and the stacking promoting effect is particularly enhanced. Examples of the polar functional group include a carboxyl group and a hydroxyl group. Examples of the naphthalene derivative include 2-naphthol, 1-naphthol, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 1,3-naphthalenediol, 2,3-naphthalenediol, and 1,5-naphthalenediol.

-Anthracene derivative Anthracene derivative is a compound having an anthracene skeleton. The anthracene derivative is preferably a compound having a polar functional group. In this case, the affinity between the anthracene derivative and the conductive polymer is improved, and the stacking promoting effect is particularly enhanced. Examples of the polar functional group include a carboxyl group and a hydroxyl group. Examples of the anthracene derivative include 2,6-anthracenediol, 1,2,3-anthracene triol, 9-anthracene carboxylic acid, 2-anthracene carboxylic acid and the like.

2. 2. Method for Producing Conductive Polymer Thin Film The method for producing a conductive polymer thin film according to the embodiment of the present invention includes a thin film forming step.

In the thin film forming step, a thin film is formed by applying the above conductive polymer composition on a substrate and then performing a heat treatment.

The solvent is removed during the heat treatment. When the additive contains a reactive monomer, the polymerization reaction proceeds during the heat treatment to form an oligomer.

The base material is not particularly limited, but the base material used for the capacitor is preferable. This is because reliability is required in high temperature and high humidity environments for capacitor applications.

As the base material, for example, a material containing aluminum, tantalum, niobium or an alloy thereof can be used.

A dielectric layer may be formed on the surface of the base material. The dielectric layer can be formed, for example, by oxidizing the surface. The method for oxidizing the surface of the base material is not particularly limited, and for example, the anodic oxidation treatment is carried out by applying a voltage for about 5 to 90 minutes in an aqueous solution containing a weak acid such as phosphoric acid or adipic acid. The method can be given.

By forming a conductive polymer thin film through a dielectric layer formed on the surface of a base material, an anode body of a solid electrolytic capacitor can be formed. Further, a solid electrolytic capacitor can be manufactured by using this anode body.

The coating method is not limited, and can be performed by dropping the conductive polymer composition onto the base material or impregnating the base material with the conductive polymer composition.

1. 1. Production / Production Example 1 of dispersion (dispersion A)
400 g of propylene carbonate, 3.4 g of 3,4-ethylenedioxythiophene (EDOT) and 1.8 g of 2-naphthalene sulfonic acid were added to a 1 L flask, and the mixture was stirred for 0.25 hours. Next, under a nitrogen purge, 0.04 g of iron (III) trisparatoluenesulfonate (Fe (PTS) ₃ ), 1.8 g of OFBA (phthalaldehyde acid), 6.75 g of benzoyl peroxide, and 100 g of propylene carbonate were added, and the temperature was 40 ° C. Was stirred for 4 hours. Further, 0.9 g of 2-naphthalene sulfonic acid was added, and the mixture was stirred at 60 ° C. for 2 hours. After adding 30 g of an anion exchange resin substituted with propylene carbonate (manufactured by LANXESS MP62WS) and stirring for 24 hours, the anion exchange resin is removed, treated with an ultrasonic homogenizer, and prepared with propylene carbonate. A conductive polymer propylene carbonate dispersion A (nonvolatile content 1.0% by mass) mainly containing the structural unit represented by 1) was obtained.

-Production example 2 (dispersion liquid B)
400 g of propylene carbonate, 3.4 g of 3,4-ethylenedioxythiophene (EDOT) and 1.8 g of 2-naphthalene sulfonic acid were added to a 1 L flask, and the mixture was stirred for 0.25 hours. Next, under a nitrogen purge, 0.04 g of iron (III) trisparatoluenesulfonate (Fe (PTS) ₃ ), 3.6 g of OFBA (phthalaldehyde acid), 6.75 g of benzoyl peroxide, and 100 g of propylene carbonate were added, and the temperature was 40 ° C. Was stirred for 4 hours. Further, 0.9 g of 2-naphthalene sulfonic acid was added, and the mixture was stirred at 60 ° C. for 2 hours. After adding 30 g of an anion exchange resin substituted with propylene carbonate (manufactured by LANXESS MP62WS) and stirring for 24 hours, the anion exchange resin is removed, treated with an ultrasonic homogenizer, and prepared with propylene carbonate. A conductive polymer propylene carbonate dispersion B (nonvolatile content 1.0% by mass) mainly containing the structural unit represented by 2) was obtained.

Production Example 3 (slurry liquid C: PEDOT / naphthalene sulfonic acid)
300 g of propylene carbonate, 3.4 g of 3,4-ethylenedioxythiophene (EDOT) and 1.8 g of 2-naphthalene sulfonic acid were added to a 1 L flask, and the mixture was stirred for 0.25 hours. Then, under a nitrogen purge, 0.04 g of iron (III) trisparatoluenesulfonate (Fe (PTS) ₃ ), 6.75 g of benzoyl peroxide, and 100 g of propylene carbonate were added, and the mixture was stirred at 40 ° C. for 4 hours. Further, 0.9 g of 2-naphthalene sulfonic acid was added, and the mixture was stirred at 60 ° C. for 2 hours. After adding 30 g of an anion exchange resin substituted with propylene carbonate (manufactured by LANXESS MP62WS) and stirring for 24 hours, the anion exchange resin was removed, the solution was prepared with propylene carbonate, and the propylene carbonate slurry solution C of PEDOT / naphthalene sulfonic acid was prepared. (Non-volatile content 1.0% by mass) was obtained.

2. 2. Production of Conductive Polymer Compositions of Examples and Comparative Examples The conductive polymer compositions of Examples and Comparative Examples were produced by the following methods. The outline of the conductive polymer composition is shown in Tables 1 to 3.

・ Example 1
5 g of dispersion liquid A, 0.5 g of slurry liquid C, and 0.25 g of 1% by mass propylene carbonate solution of 2-naphthalene sulfonic acid were added to a 9 ml bottle and treated with an ultrasonic homogenizer to disperse the conductive polymer composition. The liquid was prepared.

-Other Examples / Comparative Examples The conductive polymer composition was prepared in the same manner as in Example 1 except that the types and blending amounts of the conductive polymer and the additive were changed as shown in Tables 1 to 3. The dispersion was prepared. Additives were added in a 1% by mass solution of propylene carbonate.

3. 3. Various Evaluations The following evaluations were carried out using the conductive polymer compositions of the above Examples and Comparative Examples. The results are shown in Tables 1 to 3.

Details of various evaluations are as follows.

-Measurement of conductivity After potting the dispersion of the conductive polymer composition of Examples and Comparative Examples on a glass plate, it is dried at 150 ° C. for 30 minutes to form a conductive polymer film of 2 cm square and 1.5 μm in thickness. Made. The conductivity of this conductive polymer film was measured. The conductivity was measured using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech).

The conductivity improvement rate was calculated based on the following formulas 1 and 2. The reference value is the conductivity of the conductive polymer film produced by using the dispersion liquid A or B without the addition of additives.
(Equation 1) Conductivity improvement rate (%) = (increase from standard value / standard value) x 100
(Equation 2) Amount of increase from the reference value = Conductivity of the conductive polymer film of Examples and Comparative Examples-Reference value

Moisture and heat resistance test After potting the dispersion of the conductive polymer composition of Examples and Comparative Examples on a glass plate, it was dried at 150 ° C. for 30 minutes to form a conductive polymer film of 2 cm square and 1.5 μm thickness. Made.

Then, the coating film was left in an environment of 85 ° C./85%, and the state of the coating film after 7 days was visually confirmed and evaluated according to the following criteria.
〇: No change △: Slight cracks occur on the surface layer ×: Cracks occur overall

Further, the conductivity of the coating film was measured before leaving the coating film in an environment of 85 ° C./85% (before the test) and after leaving it for 7 days (after the test), and based on the following formula 3. The conductivity maintenance rate was calculated. The conductivity was measured using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech).
(Equation 3) Conductivity maintenance rate (%) = (conductivity after test / conductivity before test) x 100

-Heat resistance test The conductivity maintenance rate was calculated by the same method as the moisture heat resistance test except that the environmental conditions were changed to 125 ° C.

4. Discussion In all the examples, good results were obtained in all the evaluation items.
In Comparative Example 1, the conductive polymer composition did not contain an additive, and the results in all the evaluation items were not good.
In Comparative Example 2, an attempt was made to prepare a coating film using only the slurry liquid C, but various evaluations could not be performed because a uniform coating film could not be prepared.
In Comparative Example 3, the conductive polymer composition contained carbazole having a structure similar to that of dibenzothiophene and organic sulfonic acid, but the results in all the evaluation items were not good. It is considered that the reason is that carbazole is a compound containing a nitrogen atom having an unshared electron pair, so that the stacking promoting effect of the organic sulfonic acid is canceled out.

Claims

A conductive polymer composition containing a solvent, a π-conjugated conductive polymer, and an additive.
The conductive polymer has at least one of the structural units represented by the general formula (1) or (2).
The additive is a conductive polymer composition containing an aromatic stacking accelerator that promotes stacking of the conductive polymer and an organic sulfonic acid.

(In the general formulas (1) and (2), R 1 may have a substituent, respectively, an alkyl group having 1 or more and 12 or less carbon atoms, an alkyl ether group having 1 or more and 12 or less carbon atoms, and a carbon number of carbon atoms. Represents an alkoxy group of 1 or more and 12 or less, an alkylene oxide group of 1 or more and 12 or less carbon atoms, an aromatic group, or a heterocyclic group. R 2 is an oxygen atom or a sulfur atom, respectively, and R 3 is hydrogen, respectively. It may have an atom or a substituent, an alkyl group having 1 to 12 carbon atoms, an alkyl ether group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 1 to 12 carbon atoms. Represents an alkylene oxide group, an aromatic group, or a heterocyclic group. A − is a monoanion derived from a dopant. N is 2 or more and 300 or less.)
The conductive polymer composition according to claim 1.
The stacking accelerator is a conductive polymer composition which is a multi-ring compound having a plurality of aromatic rings constituting a π-conjugated system or a precursor of the multi-ring compound.
The conductive polymer composition according to claim 1 or 2.
The stacking accelerator is a conductive polymer composition containing at least one selected from the group consisting of polythiophene, thiophene derivative, dithiol derivative, naphthalene derivative, and anthracene derivative.
The conductive polymer composition according to claim 3.
The additive is a conductive polymer composition containing the polythiophene.
The conductive polymer composition according to claim 4.
The polythiophene is a conductive polymer composition which is a polymer of a monomer having a structure represented by the general formula (3).

(In the general formula (3), R 2 is an oxygen atom or a sulfur atom, respectively, and R 3 is an alkyl group having 1 or more and 12 or less carbon atoms, which may have a hydrogen atom and a substituent, respectively. Represents an alkyl ether group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylene oxide group having 1 to 12 carbon atoms, an aromatic group, or a heterocyclic group.
The conductive polymer composition according to claim 3.
The additive is a conductive polymer composition containing a thiophene derivative.
The conductive polymer composition according to claim 6.
The thiophene derivative is a conductive polymer composition having a structure represented by the general formula (3).

(In the general formula (3), R 2 is an oxygen atom or a sulfur atom, respectively, and R 3 is an alkyl group having 1 or more and 12 or less carbon atoms, which may have a hydrogen atom and a substituent, respectively. Represents an alkyl ether group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylene oxide group having 1 to 12 carbon atoms, an aromatic group, or a heterocyclic group.
The conductive polymer composition according to any one of claims 1 to 7.
A conductive polymer composition containing 1 to 40 parts by mass of the stacking accelerator with respect to 100 parts by mass of the conductive polymer.
The conductive polymer composition according to claim 8.
A conductive polymer composition containing 2 to 25 parts by mass of the stacking accelerator with respect to 100 parts by mass of the conductive polymer.
The conductive polymer composition according to any one of claims 1 to 9.
The stacking accelerator is a conductive polymer composition containing no nitrogen atom having an unshared electron pair.
The conductive polymer composition according to any one of claims 1 to 10.
The organic sulfonic acid is a conductive polymer composition which is naphthalene sulfonic acid.
The conductive polymer composition according to any one of claims 1 to 11.
A conductive polymer composition containing 0.5 to 30 parts by mass of the organic sulfonic acid with respect to 100 parts by mass of the conductive polymer.
The conductive polymer composition according to claim 12.
A conductive polymer composition containing 1 to 15 parts by mass of the organic sulfonic acid with respect to 100 parts by mass of the conductive polymer.