JP2005298563A - Conductive composition, conductive coating, capacitor and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive composition and a conductive coating capable of forming a layer excellent in conductivity and heat resistance in a simple process; to provide a capacitor capable of achieving low ESR, excellent in heat resistance and securing operation of a dielectric layer restoration capability; and to provide a method for manufacturing the capacitor easily and at a low cost. <P>SOLUTION: The conductive composition comprises a soluble conductive polymer and whiskers covered with the conductive polymer. The conductive coating comprises the conductive composition and water or an organic solvent. The conductive coating is coated and dried on a dielectric layer composed of an oxide film formed on an anode composed of a porous material of a valve metal to form a cathode containing the conductive composition on the surface of the dielectric layer to obtain the capacitor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive composition, a conductive paint, a capacitor, and a method for manufacturing the same.

  In recent years, with the digitization of electronic equipment, capacitors used for this have been required to reduce the impedance in the high frequency region. Conventionally, in order to meet this requirement, an anode made of a porous body of valve metal such as aluminum, tantalum, niobium, a dielectric layer made of an oxide film of the valve metal, pyrrole, thiophene, etc. formed on this surface A so-called functional capacitor having a cathode made of a conductive polymer is used.

  The functional capacitor includes an anode made of a porous body of a valve metal, a dielectric layer made of an oxide film of the valve metal, and a cathode made of a solid electrolyte layer, a carbon layer and a silver layer laminated on the surface. What it has is common (patent document 1). A conductive polymer is used for the solid electrolyte.

As a method for forming a solid electrolyte layer made of a conductive polymer on a dielectric layer, electrolytic polymerization or chemical polymerization is employed.
In the electropolymerization as disclosed in Patent Document 2, it is necessary to form a conductive layer made of manganese oxide on the surface of the porous body of the valve metal, and then perform electropolymerization of the precursor monomer of the conductive polymer using this as an electrode There is. However, it is very complicated to form a solid electrolyte layer by electrolytic polymerization after forming a conductive layer, and since manganese oxide has low conductivity, a highly conductive conductive polymer is used. The effect has faded.

  Further, in the chemical polymerization as disclosed in Patent Document 3, the production time of the capacitor is greatly reduced because the polymerization time is long. In addition, since the oxidant cannot be sufficiently washed, the surface of the dielectric layer is eroded by the oxidant, and the leakage current characteristic is lowered or the moisture resistance is lowered.

  If the conductive polymer is dissolved in a solvent to form a paint and can be applied on the dielectric layer, the solid electrolyte layer can be formed by a simple method. However, the conductive polymer is usually generated as insoluble and infusible particles and does not dissolve in the solvent. As described in Patent Document 4, a conductive polymer in which a long-chain alkyl group is introduced at the β-position of pyrrole and is soluble in a solvent has been proposed. However, this conductive polymer has a low electrical conductivity due to a long-chain alkyl group, and cannot be applied to a capacitor that requires a high electrical conductivity.

  The conductive polymer used for the solid electrolyte layer is required to have high conductivity in order to reduce the ESR (equivalent series resistance) of the capacitor. In order to obtain this high conductivity, for example, as shown in Patent Document 5, attempts have been made to highly control polymerization conditions in chemical polymerization. However, in this case, a complicated process is usually complicated even in the usual case, which is an obstacle to simplification of the process and cost reduction.

Note that the role of the conductive polymer used in the solid electrolyte layer is to penetrate into the porous body and contact with a larger area of the dielectric layer to increase the capacity and to remove the missing portion of the dielectric layer. The purpose is to prevent leakage current from a defect portion of the dielectric layer by repairing with a conductive polymer. As a mechanism for repairing the dielectric layer by the conductive polymer, a partial high heat generated by a leakage current when the defective portion of the dielectric layer is generated causes the conductive polymer in the defective portion of the dielectric layer. It is considered that dedoping or decomposition occurs and the conductive polymer is insulated to prevent leakage current. Therefore, it is not possible to form the carbon layer or the silver layer directly on the dielectric layer by omitting the solid electrolyte layer.
JP 2003-37024 A JP-A-63-158829 JP 63-173313 A Japanese Patent No. 3024867 Japanese Patent Laid-Open No. 11-74157

Accordingly, an object of the present invention is to provide a conductive composition and a conductive paint that can form a layer having excellent conductivity and heat resistance by a simple process such as coating and drying.
In addition, an object of the present invention is to provide a capacitor that can achieve low ESR, has excellent heat resistance, and has a reliable dielectric layer repair function, and a manufacturing method that can manufacture this capacitor easily and at low cost. There is to do.

That is, the conductive composition of the present invention is characterized by containing a soluble conductive polymer and a whisker coated with the conductive polymer.
Here, it is desirable that the soluble conductive polymer includes a polymer compound having an anion group and / or an electron-withdrawing group in the molecule and a conductive polymer.
Furthermore, the conductive composition of the present invention desirably contains a dopant.

Moreover, it is desirable for the whisker to have a sulfo group and / or a carboxyl group on the surface.
The mass ratio of the polymer compound to the conductive polymer in the soluble conductive polymer is preferably 5:95 to 99: 1.
The conductive paint of the present invention is characterized by containing the conductive composition of the present invention and water or an organic solvent.

The capacitor of the present invention comprises an anode made of a porous body of valve metal, a dielectric layer made of an oxide film of the valve metal, and a cathode containing the conductive composition of the present invention. .
In the method for producing a capacitor of the present invention, a dielectric layer made of an oxide film of the valve metal is formed on an anode made of a porous body of the valve metal, and the conductive material according to claim 6 is formed on the dielectric layer. A coating material is applied and dried to form a cathode containing a conductive composition on the surface of the dielectric layer.

According to the conductive composition and conductive paint of the present invention, a layer excellent in conductivity and heat resistance can be formed by a simple process such as coating and drying.
In addition, the capacitor of the present invention can achieve low ESR, has excellent heat resistance, and the dielectric layer repair function works reliably.
According to the method for manufacturing a capacitor of the present invention, it is possible to easily and inexpensively manufacture a capacitor that can achieve low ESR, has excellent heat resistance, and functions reliably in a dielectric layer repair function.

The present invention will be described in detail below.
<Conductive composition>
The conductive composition of the present invention contains a soluble conductive polymer and whiskers coated with the conductive polymer.

(Soluble conductive polymer)
The soluble conductive polymer in the present invention is a polymer having solubility in water or an organic solvent described later and having conductivity. As such a soluble conductive polymer, those having solubility in water or an organic solvent alone; and a polymer compound having an anionic group and / or an electron-withdrawing group in the molecule described later; By mixing the conductive polymer, those having high solubility in water or an organic solvent can be mentioned without depending on the monomer type and substituent of the conductive polymer.

Examples of the soluble conductive polymer having solubility alone in water or an organic solvent include, for example, substituted or unsubstituted polyaniline; polypyrrole substituted at the β-position by an alkyl group having 4 or more carbon atoms, an ester group, or an ether group, Polythiophene; and a copolymer obtained by copolymerizing two or more precursor monomers of these conductive polymers.
Among these soluble conductive polymers, a soluble conductive polymer containing a polymer compound having an anionic group and / or an electron-withdrawing group in the molecule and a conductive polymer is an electrical conductivity of the conductive polymer. Therefore, it is preferable that the solubility in water or an organic solvent can be imparted without significantly lowering.

(Conductive polymer)
Examples of the conductive polymer include substituted or unsubstituted polyaniline, substituted or unsubstituted polypyrrole, substituted or unsubstituted polythiophene, and a copolymer obtained by copolymerizing two or more precursor monomers of these conductive polymers. Is mentioned. Among them, polypyrrole, polythiophene, poly N-methylpyrrole, poly-3-methylthiophene, poly-3-methoxythiophene, a copolymer obtained by copolymerizing two or more precursor monomers of these conductive polymers, resistance value, cost, It is preferably used from the viewpoint of reactivity.
In particular, alkyl-substituted compounds such as poly-N-methylpyrrole and poly-3-methylthiophene are more preferable because of the effect of improving the solubility in water or organic solvents. Among alkyl groups, a methyl group is preferred because it does not adversely affect conductivity.

(Polymer compound)
A polymer compound having an anionic group and / or an electron-withdrawing group in the molecule has a function of dissolving the conductive polymer in water or an organic solvent.
Examples of the polymer compound having an anionic group in the molecule include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly-2-acrylamido-2-methylpropane sulfonic acid. , Polyisoprene sulfonic acid, polyacrylic acid and the like.

  Examples of the polymer compound having an electron-withdrawing group in the molecule include polymer compounds having an electron-withdrawing group such as a cyano group, a nitro group, a formyl group, a carbonyl group, and an acetyl group, such as polyacrylonitrile and polymethacrylonitrile. , Acrylonitrile-styrene resin, acrylonitrile-butadiene resin, acrylonitrile-butadiene-styrene resin, a resin obtained by cyanoethylation of a hydroxyl group or amino group-containing resin (for example, cyanoethylcellulose), polyvinylpyrrolidone, alkylated polyvinylpyrrolidone, nitrocellulose, and the like. .

  A polymer compound is a copolymer obtained by copolymerizing two or more monomers having an anionic group in the molecule; a copolymer obtained by copolymerizing two or more monomers having an electron-withdrawing group in the molecule; It may be a copolymer obtained by copolymerizing a monomer having an anionic group and a monomer having an electron withdrawing group in the molecule.

  Further, the vinyl compound may be copolymerized with other vinyl compounds. Examples of the other vinyl compound include polymerizable vinyl compounds such as styrene, butadiene, acrylic acid, methacrylic acid, hydroxyacrylic acid, hydroxymethacrylic acid, acrylic acid ester, methacrylic acid ester, and p-vinyltoluene. By copolymerizing these polymerizable vinyl compounds, the solubility in water or an organic solvent can be controlled.

  The polymer compound may contain a synthetic rubber component for improving impact resistance, an anti-aging agent, an antioxidant, and an ultraviolet absorber for improving environmental resistance. However, an amine compound as an antioxidant may inhibit the action of an oxidant used when a conductive polymer is obtained by polymerization. Therefore, an amine antioxidant may be avoided using a phenolic antioxidant. Care should be taken such as mixing after polymerization.

(Whisker)
The whisker in the present invention improves the heat resistance and film strength of the conductive polymer.
Examples of whiskers include potassium titanate whiskers, titania whiskers, alumina whiskers, silica whiskers, alumina / silica whiskers, silicon carbide whiskers, silicon nitride whiskers, mullite whiskers, magnesia whiskers, magnesium borate whiskers, aluminum borate whiskers, and oxidation. Zinc whiskers, titanium boride whiskers and the like can be mentioned. In particular, whiskers having a wire diameter of 0.1 to 5 μm and a fiber length of 3 to 1000 μm are preferably used.

  Moreover, it is preferable that the whisker has a sulfo group (sulfonic acid group) and / or a carboxyl group (carboxylic acid group) on the surface thereof. By having a sulfo group or a carboxyl group on the surface, the dispersibility of the whisker in the conductive polymer is improved, and further, the dopant functions as a dopant to the conductive polymer and has excellent heat resistance. The method for introducing a sulfo group and / or a carboxyl group onto the whisker surface is not particularly limited, and examples thereof include known surface treatment methods such as concentrated sulfuric acid treatment and peroxide treatment.

The surface of the whisker needs to be coated with a conductive polymer. If the surface of the whisker is covered with a conductive polymer, for the following reasons, the conductivity of the conductive composition is improved, the formation of a conductive path in the coating film made of the conductive composition, the heat resistance of the conductive composition It is possible to improve the performance.
If the solubility of the conductive polymer in water or an organic solvent is increased to improve the permeability to the porous material, the conductivity of the conductive polymer will be lower than that of the insoluble conductive polymer. There is a tendency. In order to compensate for the decrease in conductivity of the conductive composition due to such a soluble conductive polymer, a whisker whose surface is coated with a conductive polymer having good conductivity is added to the conductive composition. Thereby, the electroconductivity of an electroconductive composition can be improved, improving the permeability to a porous body.
Further, by using long fiber whiskers, a conductive path is easily formed in the coating film made of the conductive composition, and the conductivity is further improved. Here, the smaller the diameter of the whisker, the volume resistance of the entire whisker can be suppressed. Furthermore, the effect of improving the heat resistance by whiskers can be obtained at the same time.

  From the viewpoint of conductivity, the conductive polymer coated on the whisker surface is insoluble conductive polymer, that is, substituted or unsubstituted polyaniline, substituted or unsubstituted polypyrrole, substituted or unsubstituted polythiophene, A copolymer obtained by copolymerizing two or more kinds of conductive polymer precursor monomers is preferable. Among them, polypyrrole, polythiophene, poly N-methylpyrrole, poly-3-methylthiophene, poly-3-methoxythiophene, a copolymer obtained by copolymerizing two or more precursor monomers of these conductive polymers, resistance value, cost, It is preferably used from the viewpoint of reactivity. Moreover, even if it is a soluble conductive polymer, if it is a high molecular weight soluble conductive polymer, since it has high electroconductivity, it can be used for the coating of the whisker surface.

  As a method of coating the whisker surface with a conductive polymer, a so-called chemical polymerization method is simple. In the coating by the chemical polymerization method, first, a precursor monomer of a conductive polymer and a dopant, if necessary, are added to a solvent in which whiskers are dispersed, and the mixture is sufficiently mixed by stirring. Then, after dropping the oxidant into the mixed solution and proceeding the polymerization, the product is purified by removing the oxidant, residual monomers and by-products from the product, and the surface is made of conductive polymer. A whisker coated with is obtained.

  Alternatively, the whisker may be treated with a solution obtained by dissolving a soluble conductive polymer containing a polymer compound and a conductive polymer in a solvent, and the surface may be coated with the soluble conductive polymer. In this case, the polymer compound used for the treatment is preferably a polymer compound having a polarity different from that of a polymer compound added separately in order to obtain a conductive composition. If it does in this way, it can prevent that the high molecular compound of a whisker surface melt | dissolves during a dispersion process.

(Dopant)
The conductive composition of the present invention preferably contains a dopant in order to improve both conductivity and heat resistance. Usually, a halogen compound, Lewis acid, proton acid, or the like is used as a dopant. Specifically, organic acids such as organic carboxylic acid and organic sulfonic acid, organic cyano compounds, fullerene, hydrogenated fullerene, fullerene hydroxide, Examples thereof include carboxylic acid fullerene and sulfonic acid fullerene.

Examples of organic acids include alkylbenzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl naphthalene disulfonic acid, naphthalene sulfonic acid formalin polycondensate, melamine sulfonic acid formalin polycondensate, naphthalene disulfonic acid, naphthalene trisulfonic acid, dinaphthylmethane disulfonic acid, Anthraquinone sulfonic acid, anthraquinone disulfonic acid, anthracene sulfonic acid, pyrene sulfonic acid and the like can be mentioned, and metal salts thereof can also be used.
Examples of the organic cyano compound include dichlorodicyanobenzoquinone (DDQ), tetracyanoquinodimethane, and tetracyanoazanaphthalene.

(Preparation of conductive composition)
The conductive composition of the present invention can be prepared as follows.
First, the polymer compound is dissolved in a solvent that can dissolve the polymer compound, and the precursor monomer of the conductive polymer and, if necessary, a dopant are added to the solution, and the mixture is sufficiently stirred to prepare a monomer-containing solution. . Next, an oxidant is dropped into the monomer-containing solution to allow the polymerization to proceed, and then this is purified by removing the oxidant, residual monomers, and by-products from the polymer compound / conductive polymer complex. Thus, a soluble conductive polymer containing the polymer compound and the conductive polymer is obtained. In addition, after obtaining a soluble conductive polymer, a dopant may be added to this and a soluble conductive polymer may be doped.

A whisker whose surface is coated with a conductive polymer is added to the soluble conductive polymer, and the mixture is thoroughly mixed, stirred, and dispersed to obtain a conductive composition. In addition, you may add a whisker beforehand in the case of preparation of a soluble conductive polymer. That is, if a polymer compound, a precursor monomer, a dopant, and a whisker are simultaneously added to a solvent and an oxidant is added dropwise to proceed with polymerization, a conductive polymer is formed on the whisker surface simultaneously with the formation of a soluble conductive polymer. A film of a conductive polymer can be formed.
The conductive polymer in the soluble conductive polymer and the conductive polymer covering the whisker may be the same or different.

  As the oxidizing agent for polymerizing the precursor monomer of the conductive polymer, known ones can be used, for example, metal halogen compounds such as ferric chloride, boron trifluoride, and aluminum chloride; hydrogen peroxide, benzoyl peroxide Peroxides such as potassium persulfate, sodium persulfate and ammonium persulfate; ozone, oxygen and the like.

  Examples of the solvent for dissolving the polymer compound include water, methanol, ethanol, propylene carbonate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, And toluene. These can be used alone or in admixture of two or more.

  The mass ratio of the polymer compound to the conductive polymer in the soluble conductive polymer (polymer compound: conductive polymer) is preferably 5:95 to 99: 1. When the amount of the conductive polymer is less than this range, sufficient conductivity may not be obtained. When the amount is more than this range, the solubility in water or an organic solvent tends to be poor.

  The mass ratio of the soluble conductive polymer to the whisker whose surface is coated with the conductive polymer (soluble conductive polymer: whisker whose surface is coated with the conductive polymer) is 5:95 to 99. .9: 0.1 is preferable. If the number of whiskers whose surface is covered with the conductive polymer is less than this range, the conductivity may not be sufficiently improved, and if it is more than this range, the film forming property may be lacking.

  Since the conductive composition described above contains a soluble conductive polymer, it can be coated with water or an organic solvent. Therefore, it becomes possible to apply | coat to various base materials and to form the layer which has electroconductivity. In addition, since this conductive composition contains whiskers whose surfaces are coated with a conductive polymer, not only the conductivity of the layer formed from the conductive composition is increased, but also heat resistance, Strength also increases.

<Conductive paint>
The conductive paint of the present invention contains the above-described conductive composition and water or an organic solvent. As an organic solvent, things other than water are mentioned among the solvents which melt | dissolve the high molecular compound mentioned above.
The conductive paint may be produced by adding the conductive composition to water or an organic solvent, or the conductive composition containing the solvent obtained by the above-described method for producing a conductive composition is used as it is. May be.

<Capacitor>
The capacitor of the present invention has an anode made of a porous body of valve metal, a dielectric layer made of an oxide film of the valve metal adjacent to the anode, and a cathode containing the conductive composition.
Since the cathode of this capacitor is formed from the above conductive composition, the capacitor has excellent performance and can withstand harsh usage environments.
Here, examples of the valve metal include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among these, aluminum, tantalum, and niobium are suitable for use in the capacitor anode. is there.

An example of the method for manufacturing a capacitor of the present invention will be described. In this example of the capacitor manufacturing method, first, a dielectric layer made of an oxide film of the valve metal is formed on an anode made of a porous body of the valve metal to obtain a capacitor intermediate. Here, as a method of manufacturing the capacitor intermediate, for example, after etching the aluminum foil to increase the surface area, the surface is oxidized, or the surface of the sintered body of tantalum particles and niobium particles is oxidized and pellets The method of making it.
Next, a conductive paint is applied to the capacitor intermediate by a method such as dipping or spray coating, and then dried to form a cathode containing the conductive composition on the surface of the dielectric layer to obtain a capacitor.

  When applying the conductive paint by the immersion method, for example, the capacitor intermediate is immersed in the conductive paint and penetrates into the porous body, and if necessary, ultrasonic waves, vibration, reduced pressure, heating, etc. An operation may be added to assist the penetration into the porous body. Further, the coating thickness may be adjusted by repeatedly dipping and drying.

  Since the capacitor described above includes a soluble conductive polymer having high conductivity and a whisker coated with the conductive polymer, the ESR can be reduced. Moreover, since the whisker whose surface is coated with a conductive polymer is included in the cathode, the heat resistance of the cathode is increased, and as a result, the heat resistance of the capacitor is improved. In addition, since the soluble conductive polymer can penetrate into the porous body together with water or an organic solvent, the dielectric layer repair function by the soluble conductive polymer works reliably.

  According to the method for producing a capacitor of the present invention, the conductive composition is applied to the surface of the dielectric layer by simply applying a conductive paint on the dielectric layer and drying it, regardless of the chemical polymerization method or the electrolytic polymerization method. Since a cathode including the same can be formed, it is possible to reduce the ESR, and to easily and inexpensively manufacture a capacitor that is excellent in heat resistance and in which the function of repairing the dielectric layer is ensured.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
(1) Production of polymer compound:
Acrylonitrile (50 g) and styrene (10 g) were dissolved in 500 ml of toluene, 1.5 g of azobisisobutyronitrile was added as a polymerization initiator, and the mixture was polymerized at 50 ° C. for 5 hours. And the polymer produced | generated by superposition | polymerization was wash | cleaned with methanol, and the high molecular compound was obtained.

(2) Production of whisker coated with conductive polymer:
5 g of potassium titanate whisker (manufactured by Otsuka Chemical Co., Ltd., Tismo N) was dispersed in 500 ml of acetonitrile, 10 g of pyrrole and 10 g of sodium octadecylnaphthalenesulfonate were added thereto, and the mixture was stirred for 1 hour while cooling to −20 ° C. To this, an oxidant solution in which 250 g of ferric chloride was dissolved in 1250 ml of acetonitrile was dropped over 2 hours while maintaining at −20 ° C., and stirring was further continued for 12 hours to polymerize pyrrole.
After completion of the reaction, 2000 ml of methanol was added thereto, the precipitate was filtered, washed with methanol and pure water until the filtrate became transparent, and a whisker coated with a conductive polymer was obtained.

(3) Production of soluble conductive polymer:
10 g of the polymer compound produced in (1) was dissolved in 90 g of acetonitrile, 50 g of pyrrole and 20 g of sodium octadecylnaphthalenesulfonate were added thereto, and the mixture was stirred for 1 hour while cooling to -20 ° C. To this, an oxidant solution in which 250 g of ferric chloride was dissolved in 1250 ml of acetonitrile was dropped over 2 hours while maintaining −20 ° C., and stirring was further continued for 12 hours to polymerize pyrrole.
After completion of the reaction, 2000 ml of methanol was added thereto, the precipitate was filtered, and washed with methanol and pure water until the filtrate became transparent to obtain a soluble conductive polymer.

(4) Preparation of conductive paint:
The soluble conductive polymer produced in (3) was dissolved in N, N-dimethylacetamide (DMAc) to prepare a soluble conductive polymer solution having a concentration of 5% by mass. Then, 10 parts by weight of whisker coated with the conductive polymer produced in (2) is added to 100 parts by weight of the solid content of the soluble conductive polymer solution, and these are mixed, stirred, and made conductive. A paint was obtained.

The obtained conductive paint was evaluated for electrical conductivity (conductivity) and heat resistance by the following test methods. The results are shown in Table 1.
<Test method>
(A) Electrical conductivity:
The electrical conductivity (unit: S / cm) of a 2 μm thick coating formed by applying and drying a conductive paint on a PET film was measured using a conductivity meter (trade name: Loresta MCP-T600). ("Initial" column in the table).
(B) Heat resistance:
A conductive coating is applied on a PET film and dried to form a 10 μm thick coating, and then left in an oven at 125 ° C. for 240 hours. It was used as an index.

[Example 2]
(1) Production of soluble conductive polymer:
10 g of polystyrene sulfonic acid, which is a polymer compound, was dissolved in 90 g of water, 50 g of pyrrole and 20 g of sodium octadecylnaphthalene sulfonate were added thereto, and the mixture was stirred for 1 hour while cooling to 0 ° C. To this, an oxidant solution in which 250 g of ferric chloride was dissolved in 1250 ml of water was dropped over 2 hours while maintaining 0 ° C., and stirring was further continued for 12 hours to polymerize pyrrole.
After completion of the reaction, the resulting solution was treated with an ultrafiltration device to remove unnecessary ions in the solution and concentrated to a concentration of 5% by mass to obtain a soluble conductive polymer solution.

(2) Preparation of conductive paint:
To 100 parts by mass of the solid content of the soluble conductive polymer solution produced in (1), 10 parts by mass of whiskers coated with the conductive polymer produced in (2) of Example 1 were added, and these were mixed. The mixture was stirred to obtain a conductive paint.
The obtained conductive paint was tested in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
(1) Production of whisker coated with conductive polymer:
5 g of aluminum borate whisker (manufactured by Shikoku Kasei Kogyo Co., Ltd., Arbolex) was added to 100 ml of concentrated sulfuric acid and refluxed at 90 to 100 ° C. for 16 hours to modify the whisker surface with a sulfo group. 5 g of a sulfo group-containing whisker was dispersed in 100 ml of acetonitrile, 10 g of pyrrole and 5 g of p-toluenesulfonic acid were added thereto, and the mixture was stirred for 1 hour while being cooled to −20 ° C. To this, an oxidant solution in which 15 g of ferric chloride was dissolved in 100 ml of acetonitrile was dropped over 2 hours while maintaining at −20 ° C., and stirring was further continued for 12 hours to polymerize pyrrole.
After completion of the reaction, the whisker was filtered and washed with methanol and pure water until the filtrate became transparent to obtain a whisker coated with a conductive polymer.

(2) Production of polymer compound:
30 g of acrylonitrile and 20 g of methyl methacrylate were dissolved in 500 ml of toluene, 1.5 g of azobisisobutyronitrile was added as a polymerization initiator, and polymerization was carried out at 50 ° C. for 5 hours. And the polymer produced | generated by superposition | polymerization was wash | cleaned with methanol, and the high molecular compound was obtained.

(3) Production of soluble conductive polymer:
10 g of the polymer compound produced in (2) was dissolved in 90 g of acetonitrile, 50 g of pyrrole and 20 g of sodium anthraquinone disulfonate were added thereto, and the mixture was stirred for 1 hour while cooling to −20 ° C. To this, an oxidant solution in which 250 g of ferric chloride was dissolved in 1250 ml of acetonitrile was dropped over 2 hours while maintaining −20 ° C., and stirring was further continued for 12 hours to polymerize pyrrole.
After completion of the reaction, 2000 ml of methanol was added thereto, the precipitate was filtered, and washed with methanol and pure water until the filtrate became transparent to obtain a soluble conductive polymer.

(4) Preparation of conductive paint:
The soluble conductive polymer produced in (3) was dissolved in N, N-dimethylacetamide (DMAc) to prepare a soluble conductive polymer solution having a concentration of 5% by mass. Then, 15 parts by weight of whisker coated with the conductive polymer produced in (1) is added to 100 parts by weight of the solid content of the soluble conductive polymer solution, and these are mixed, stirred, and made conductive. A paint was obtained.
The obtained conductive paint was tested in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
3-hexylthiophene 10 was dissolved in 100 ml of acetonitrile and stirred for 1 hour while cooling to 5 ° C. To this, an oxidizing agent solution in which 50 g of ferric chloride was dissolved in 250 ml of acetonitrile was dropped over 2 hours while maintaining 5 ° C., and stirring was further continued for 12 hours to polymerize 3-hexylthiophene.
After completion of the reaction, 2000 ml of methanol was added thereto, the precipitate was filtered, and washed with methanol and pure water until the filtrate became transparent to obtain a soluble conductive polymer.
This soluble conductive polymer was dissolved in N, N-dimethylacetamide (DMAc) to prepare a soluble conductive polymer solution having a concentration of 5% by mass, which was used as a conductive paint.
The obtained conductive paint was tested in the same manner as in Example 1. The results are shown in Table 1.

The conductive composition of the present invention can be suitably used as a cathode material for functional capacitors such as aluminum electrolytic capacitors, tantalum electrolytic capacitors, niobium electrolytic capacitors, as well as antistatic coatings such as antistatic coatings and antistatic packaging materials. It can be used for electrophotographic equipment parts such as materials, electromagnetic wave shielding materials for shielding electromagnetic waves on liquid crystal screens and plasma display screens, transfer belts, developing rolls, charging rolls, and transfer rolls.

Claims (8)

A soluble conductive polymer;
A conductive composition comprising a whisker coated with a conductive polymer.   The conductive composition according to claim 1, wherein the soluble conductive polymer contains a polymer compound having an anionic group and / or an electron-withdrawing group in the molecule and a conductive polymer.   Furthermore, a dopant is contained, The electrically conductive composition of Claim 1 or Claim 2 characterized by the above-mentioned.   The electrically conductive composition according to any one of claims 1 to 3, wherein the whisker has a sulfo group and / or a carboxyl group on a surface thereof.   5. The conductive composition according to claim 2, wherein a mass ratio of the polymer compound to the conductive polymer in the soluble conductive polymer is 5:95 to 99: 1. .   A conductive paint comprising the conductive composition according to claim 1 and water or an organic solvent. An anode made of a porous body of valve metal,
A dielectric layer comprising an oxide film of the valve metal;
A capacitor comprising: a cathode containing the conductive composition according to claim 1. A dielectric layer made of an oxide film of the valve metal is formed on an anode made of a porous body of the valve metal, and the conductive paint according to claim 6 is applied on the dielectric layer and dried to form a dielectric layer. A method for producing a capacitor, comprising forming a cathode containing a conductive composition on a surface.