KR100979380B1 - Dispersion of electroconductive composition, electroconductive composition, and use thereof - Google Patents

Abstract

(상기 화학식 1에서, R은 수소 또는 메틸기임)The present invention relates to a dispersion of the conductive composition, the conductive composition and its use,
In the presence of a phenol sulfonic acid novolak resin, sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the following formula (1), thiophene or its derivatives are electrolytically oxidized in water or in an aqueous solution consisting of a mixture of water and a water-miscible solvent. A conductive polymer obtained by polymerization and an organic acid having a high boiling point solvent or a cyclic structure are contained to form a dispersion of the conductive composition, an antistatic film is used using the conductive composition as a conductor, and the conductive composition is a solid electrolyte. It is used as a solid electrolytic capacitor to provide a conductive composition having high conductivity and excellent heat resistance, and the antistatic film or ESR having high conductivity and excellent heat resistance using the conductive composition is small and reliable under high temperature conditions. This high solid electrolytic capacitor It is characterized by providing.
(Formula 1)

(In Formula 1, R is hydrogen or methyl group)

Description

Dispersion of conductive composition, conductive composition and use thereof {DISPERSION OF ELECTROCONDUCTIVE COMPOSITION, ELECTROCONDUCTIVE COMPOSITION, AND USE THEREOF}

The present invention relates to a conductive composition obtained by drying a dispersion of a conductive composition, a dispersion of the conductive composition, an antistatic film using the conductive composition as a conductor, an antistatic sheet, and a solid electrolytic capacitor using the conductive composition as a solid electrolyte. will be.

The conductive polymer is used as a solid electrolyte of solid electrolytic capacitors such as tantalum solid electrolytic capacitors, niobium solid electrolytic capacitors, and aluminum solid electrolytic capacitors due to its high conductivity.

As the conductive polymer in this application, for example, a compound synthesized by oxidative polymerization of a polymerizable monomer such as thiophene or a derivative thereof is used.

Organic sulfonic acid is mainly used as the dopant in the oxidative polymerization, particularly chemical oxidation polymerization of polymerizable monomers such as thiophene or derivatives thereof, and among these, aromatic sulfonic acid is suitable, transition metal is used as the oxidizing agent, Among them, ferric iron is suitable, and ferric salts of aromatic sulfonic acids are usually used as oxidants and dopants in chemical oxidation polymerization of polymerizable monomers such as thiophene or derivatives thereof.

In addition, toluene sulfonic acid ferric salt, methoxybenzene sulfonic acid ferric salt, and the like are particularly useful among the ferric salts of aromatic sulfonic acid. Or it can carry out by mixing with polymerizable monomers, such as derivatives thereof, and it is reported that it is simple and suitable for industrialization (patent document 1, patent document 2).

However, the conductive polymer obtained by using toluene sulfonic acid ferric salt as an oxidant and a dopant does not have a satisfactory characteristic in initial resistance value or heat resistance, and also a methoxybenzenesulfonic acid ferric salt as an oxidizing agent and a plate The conductive polymer obtained by use as a tester had a low initial resistance value and excellent heat resistance as compared with the conductive polymer using toluene sulfonic acid ferric salt, but still not sufficiently satisfactory properties were obtained.

This is because toluene sulfonic acid ferric salt or methoxybenzenesulfonic acid ferric salt is solid and is generally used in a dissolved state, but precipitation of these solutions occurs during storage.

In other words, the use of an alcohol solution of toluene sulfonic acid ferric salt or methoxybenzenesulfonic acid ferric salt where precipitation has occurred decreases the uniformity and increases the ESR (equivalent series resistance) of the solid electrolytic capacitor using the obtained conductive polymer. Or the reliability under high temperature conditions is lowered.

When the obtained conductive polymer is used as a solid electrolyte of a solid electrolytic capacitor, the conductive polymer synthesized by the chemical oxidation polymerization method usually has no solubility in a solvent, and thus is an anode made of a porous body of valve metals such as tantalum, niobium, and aluminum. And it is necessary to form a conductive polymer layer directly on the element having a dielectric layer made of the oxide film of the valve metal.

However, forming a conductive polymer layer directly on the device as described above has a problem that it is very difficult to conditionally enforce a difficult task, thus lacking reproducibility and making process management very difficult.

Based on such a situation, the solubilization conductive polymer is actively examined (patent document 3). According to this patent document 3, it is reported that when the polystyrene sulfonic acid, ammonium persulfate, iron salt, ethylenedioxythiophene, etc. are mixed and reacted, the dispersion liquid of a conductive polymer is obtained. However, the conductive polymer obtained by this cannot be said to be sufficiently high in conductivity, and further improvement in conductivity is required for use as a solid electrolyte of a solid electrolytic capacitor.

Moreover, the conductive polymer which doped phenol sulfonic-acid novolak resin to polyaniline is reported (patent documents 4-5). However, this conductive polymer also cannot be said to have sufficiently high electrical conductivity, and further improvement in conductivity is required for use as a solid electrolyte of a solid electrolytic capacitor.

Moreover, the solubilization conductive polymer by the electrolytic oxidation polymerization method is also examined (patent documents 6-7). However, in this case, the process of taking out and solubilizing the insoluble conductive polymer formed on the electrode requires a problem that it is difficult to use industrially.

Japanese Laid-Open Patent Publication No. 2003-160647 Japanese Laid-Open Patent Publication No. 2004-265927 Japanese Patent Publication No. 2636968 Japanese Patent Publication No. 3903071 Japanese Laid-Open Patent Publication No. 2007-277569 Japanese Unexamined Patent Publication No. Hei1-161013 Japanese Laid-Open Patent Publication No. 62-181328

In view of the above circumstances, the present invention provides a conductive composition having high conductivity and excellent heat resistance, and providing an antistatic film having high conductivity and excellent heat resistance by using the conductive composition as a conductor. An object of the present invention is to provide a solid electrolytic capacitor having a low ESR and high reliability under high temperature conditions by using the conductive composition as a solid electrolyte.

The present inventors have intensively studied to solve the above problems, and as a result, thiophene or derivatives thereof in the presence of a phenol sulfonic acid novolak resin, sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the following formula (1) When electrolytic oxidation polymerization is carried out in water or in an aqueous solution composed of a mixture of water and a water-miscible solvent, most of the electrodes are not in close contact with each other, and a dispersion of the conductive polymer is obtained in a uniformly dispersed state in water or in an aqueous solution. The conductive composition obtained from the dispersion of the conductive composition containing a high boiling point solvent or an organic acid having a cyclic structure in the dispersion was found to have high conductivity and excellent heat resistance, and thus came to complete the present invention.

(In Formula 1, R is hydrogen or methyl group)

That is, the present invention comprises a thiophene or a derivative thereof in water or a mixture of water and a water miscible solvent in the presence of a phenol sulfonic acid novolak resin, sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the formula (1). A conductive liquid obtained by electrolytic oxidation polymerization in an aqueous liquid, and a dispersion of a conductive composition comprising a high boiling point solvent or an organic acid having a cyclic structure.

The present invention also relates to a conductive composition obtained by drying the dispersion of the conductive composition, an antistatic film using the conductive composition as a conductor, an antistatic sheet, and a solid electrolytic capacitor using the conductive composition as a solid electrolyte.

The electrically conductive composition of this invention is high in transparency, high in electroconductivity, and excellent in heat resistance. In addition, since the conductive composition of the present invention has high transparency and the conductive polymer is synthesized by electrolytic oxidation polymerization, the content of sulfate root based on the oxidizing agent as seen in the conductive polymer synthesized by chemical oxidation polymerization is low. There is little fall of electroconductivity, transparency fall, etc. based on remaining sulfate sulfate.

Therefore, by using this as a conductor based on the characteristics of the electrically conductive composition of this invention, an antistatic film, an antistatic resin, an antistatic sheet, etc. which are high in transparency, high in electroconductivity, and excellent in heat resistance can be obtained. In addition, by using the conductive composition of the present invention having high conductivity and excellent heat resistance as a solid electrolyte, a solid electrolytic capacitor having low ESR and high reliability under high temperature conditions can be obtained.

In the present invention, in the synthesis of the conductive polymer, phenol sulfonic acid novolak resin, sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the formula (1) is used, but they function as an excellent dispersant in the synthesis of the conductive polymer. Thiophene as a polymerizable monomer, a derivative thereof, a catalyst added as necessary, and the like are uniformly dispersed in water or an aqueous solution, and further blown into the polymer to be synthesized as a dopant, so that the conductive polymer has high conductivity. And it is thought that the said dopant functions as an excellent dispersing agent is a factor which can synthesize | combine the conductive polymer which is high in transparency, high in electroconductivity, and excellent in heat resistance.

As a phenol sulfonic acid novolak resin represented by the said Formula (1), the thing of the number average molecular weights 5,000-500,000 is preferable. This is based on the following reason.

That is, when the number average molecular weight of the said phenol sulfonic acid novolak resin is less than 5,000, there exists a possibility that electroconductivity of the electroconductive polymer obtained may become low, and also transparency may worsen. Moreover, when the number average molecular weight of the said phenol sulfonic acid novolak resin is larger than 500,000, the viscosity of the dispersion liquid of an electrically conductive composition may become high and it may become difficult to use at the time of preparation of a solid electrolytic capacitor. And as this phenol sulfonic-acid novolak resin, the number average molecular weight is preferably 10,000 or more within the said range, 400,000 or less are preferable, and 80,000 or less are more preferable.

The sulfonated polyester may be a mixture of dicarboxybenzene sulfonic acid or sulfoisophthalic acid esters such as sulfoisophthalic acid and sulfo terephthalic acid, or dicarboxybenzene sulfonic acid diesters such as sulfoisophthalic acid esters and alkylene glycols. Polycondensation polymerization in the presence of a catalyst such as antimony oxide or zinc oxide, or a mixture of the dicarboxybenzene sulfonic acid or dicarboxybenzene sulfonic acid diester, alkylene glycol, and terephthalic acid or terephthalate dimethyl, such as antimony oxide or zinc oxide It is polycondensation-polymerized in presence of the catalyst, and it is preferable that the number average molecular weights are 5,000-300,000 as said sulfonated polyester.

That is, when the number average molecular weight of the said sulfonated polyester is less than 5,000, there exists a possibility that the electroconductivity of the obtained conductive polymer may become low and transparency may worsen. Moreover, when the number average molecular weight of the said sulfonated polyester is larger than 300,000, the viscosity of the dispersion liquid of an electroconductive composition may become high and it may become difficult to use for preparation of a solid electrolytic capacitor. As this sulfonated polyester, the number average molecular weight is preferably 10,000 or more within the above range, more preferably 20,000 or more, still more preferably 100,000 or less, and even more preferably 80,000 or less.

Moreover, as polystyrene sulfonic acid, the thing of the number average molecular weights 10,000-1,000,000 is preferable.

That is, when the number average molecular weight of the said polystyrene sulfonic acid is smaller than 10,000, there exists a possibility that the electroconductivity of the electroconductive polymer obtained may become low, and also transparency may worsen. Moreover, when the number average molecular weight of the said polystyrene sulfonic acid is larger than 1,000,000, the viscosity of the dispersion liquid of a conductive composition may become high and it may become difficult to use it in manufacture of a solid electrolytic capacitor. The number average molecular weight of the polystyrene sulfonic acid is more preferably 20,000 or more within the above range, more preferably 40,000 or more, still more preferably 800,000 or less, and even more preferably 300,000 or less.

Although the dispersion liquid of this invention contains the high boiling point solvent or the organic acid which has a cyclic structure, it is in order to improve the film forming property of the electrically conductive composition obtained, and to improve electroconductivity by this. The reason why the conductivity of the conductive polymer is improved by containing a high boiling point solvent is not clearly clear at present, but, for example, when the dispersion of the conductive composition is applied to a substrate and the high boiling point solvent is taken off during drying, By increasing the layer density, it is considered that the surface spacing between the conductive polymers is narrowed and the conductivity of the conductive polymers is increased.

As said high boiling point solvent, a thing with a boiling point of 150 degreeC or more is preferable, As a specific example of such a high boiling point solvent, dimethyl sulfoxide (boiling point 189 degreeC), (gamma) -butyrolactone (boiling point 204 degreeC), sulfolane (boiling point 285) ° C), N-methylpyrrolidone (boiling point 202 ° C), dimethyl sulfone (boiling point 233 ° C), ethylene glycol (boiling point 198 ° C), diethylene glycol (boiling point 244 ° C) and the like, in particular dimethyl sulfoxide desirable. The content of the high boiling point solvent is preferably 5 to 3,000% (that is, 5 to 3,000 parts by mass of the high boiling point solvent relative to 100 parts by mass of the conductive polymer) with respect to the conductive polymer in the dispersion, particularly 20 to 700. % Is preferred. When the content of the high boiling point solvent is less than the above, the film forming property of the conductive composition may be lowered, and as a result, the action of improving the conductivity of the conductive composition may decrease. When the content of the high boiling point solvent is more than the above, It takes time for drying and there exists a possibility of causing the fall of electroconductivity rather.

The dispersion liquid of the present invention may contain an organic acid having a cyclic structure in place of the high boiling point solvent, but the inclusion of such an organic acid is intended to improve the film forming properties of the obtained conductive composition, thereby improving conductivity. . The reason why the conductivity of the conductive polymer is improved by containing an organic acid having such a cyclic structure is not clearly clear at present, but for example, when the dispersion of the conductive composition is applied to a substrate and dried, the organic acid having a cyclic structure is a conductive polymer. It is thought that it is in order to make it easy to generate | occur | produce the transfer of the hole (hole) between the layers of an electroconductive polymer between layers of a.

Examples of the organic acid having the cyclic structure include phthalic acid, phthalaldehyde acid, carboxyphenol, carboxycresol, carboxynaphthalene, dicarboxynaphthalene, thiophensulfonic acid, toluenesulfonic acid, phenol sulfonic acid, cresolsulfonic acid, naphthalene sulfonic acid, Naphthalene disulfonic acid, naphthalene trisulfonic acid, anthraquinone sulfonic acid, anthraquinone disulfonic acid, etc. are mentioned, Aromatic organic acids, such as phenol sulfonic acid, naphthalene sulfonic acid, anthraquinone sulfonic acid, are especially preferable. The content of the organic acid having a cyclic structure is preferably 5 to 500% (that is, 5 to 500 parts by mass of an organic acid having a cyclic structure with respect to 100 parts by mass of the conductive polymer) based on the mass of the conductive polymer in the dispersion. 20 to 150% is particularly preferable. When the content of the organic acid having a cyclic structure is less than the above, the film forming property of the conductive composition may be lowered, and as a result, the action of improving the conductivity of the conductive composition may be lowered, and the content of the organic acid having a cyclic structure is higher than that described above. In the case, it acts as an impurity, and the film forming property of an electroconductive composition falls, but there exists a possibility of causing a fall of electroconductivity.

In addition, since content of the conductive polymer in a dispersion liquid affects workability, etc. at the time of drying the dispersion liquid of a conductive composition into a film form etc., about 1-10 mass% is preferable normally. That is, when the content of the conductive polymer is less than the above, it takes time to dry, and when the content of the conductive polymer is more than the above, the viscosity increases and there is a possibility that workability such as when coating is lowered.

The dried product obtained by drying the dispersion liquid containing the conductive polymer and the high boiling point solvent is considered to be the main ingredient of the conductive polymer and contains a high boiling point solvent, and thus, the present invention is obtained by drying the dispersion of the conductive composition. It is expressed that it becomes an electroconductive composition. However, since the high boiling point solvent is also a solvent, there is a possibility that it almost evaporates if it is dried at a higher temperature. Even if it does not contain, it expresses as a conductive composition. In addition, when the organic acid having a cyclic structure is contained in place of the high boiling point solvent, the organic acid having the cyclic structure does not evaporate by normal drying, and thus the dried product obtained by drying a dispersion containing a conductive polymer and an organic acid having a cyclic structure. Is usually a conductive composition containing a conductive polymer and an organic acid having a cyclic structure. The dispersion liquid of the conductive polymer of the present invention may contain a high boiling point solvent and an organic acid having a cyclic structure in combination.

In the present invention, thiophene or a derivative thereof is used as the polymerizable monomer for synthesizing the conductive polymer by electrolytic oxidation polymerization, but as the derivative of thiophene in the thiophene or derivative thereof, for example, 3,4-ethylenedioxane Citiopen, 3-alkylthiophene, 3-alkoxythiophene, 3-alkyl-4-alkoxythiophene, 3,4-alkylthiophene, 3,4-alkoxythiophene, etc. are mentioned, The said alkyl group and alkoxy 1-16 are preferable and, as for carbon number of group, 1-4 are suitable especially, ie, 3, 4- ethylene dioxythiophene which has 2 carbon atoms is preferable.

The electrolytic oxidation polymerization in the synthesis of the conductive polymer is a phenol sulfonic acid novolak resin, sulfonated polyester, polystyrene sulfonic acid having a repeating unit represented by the formula (1) as a dopant (hereinafter, these are referred to as "dopant" All of them are soluble in an aqueous solution consisting of water or a mixture of water and a water-miscible solvent, so they are carried out in water or in an aqueous solution.

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

The amount of the dopant or the polymerizable monomer used in the electrolytic oxidation polymerization is not particularly limited. For example, a thiophene derivative is used as the polymerizable monomer by using a phenol sulfonic acid novolak resin having a repeating unit represented by the formula (1) as the dopant. In the case of using phosphorus 3,4-ethylenedioxythiophene as an example, phenol sulfonic acid novolak resin: 3,4-ethylenedioxythiophene = 1: 0.05-1: 5 Preference is given to phenol sulfonic acid novolak resins, in particular 3,4-ethylenedioxythiophene = 1: 0.1 to 1: 1. And this is almost the same also when using another thing as a dopant and using another thing as a polymerizable monomer.

The electrolytic oxidation polymerization can be carried out either with a constant current or with a constant voltage. For example, when electrolytic oxidation polymerization is carried out with a constant current, the current value is preferably 0.05 mA / cm 2 to 10 mA / cm 2, and 0.2 mA / cm 2 to 4 mA / cm 2 is more preferable, and when performing electrolytic oxidation polymerization at a constant voltage, as a voltage, 0.5V-10V are preferable and 1.5V-5V are more preferable. As temperature at the time of electrolytic oxidation polymerization, 5 to 95 degreeC is preferable, and 10 to 30 degreeC is especially preferable. Moreover, as polymerization time, 1 hour-72 hours are preferable, and 8 hours-24 hours are especially preferable. In electrolytic oxidation polymerization, ferrous sulfate or ferric sulfate may be added as a catalyst. Electrolytic oxidation polymerization is carried out in water or in an aqueous solution containing iron ions of these catalysts to promote polymerization of thiophene or derivatives thereof.

The conductive polymer obtained as described above is obtained immediately after polymerization and dispersed in water or in an aqueous solution, and contains iron sulfate, its decomposition product and the like used as a catalyst. Therefore, it is preferable to put the dispersion liquid of the conductive polymer containing the impurity into a disperser such as an ultrasonic homogenizer or a planetary ball mill to disperse the impurities, and then remove the metal component with a cation exchange resin. As a particle diameter of the conductive polymer at this time, 100 micrometers or less are preferable and 10 micrometers or less are especially preferable. Thereafter, sulfuric acid produced by catalytic decomposition by ethanol precipitation, ultrafiltration, anion exchange resin or the like is removed, and a high boiling point solvent or an organic acid having a cyclic structure is added.

Since the electroconductive composition of this invention is high in electroconductivity, excellent in heat resistance, and excellent in transparency, it can be used suitably as an electrical conductor of antistatic materials, such as an antistatic film, antistatic cloth, antistatic resin, and the like. In addition, since the conductive composition of the present invention has high conductivity and excellent heat resistance, it is preferably used as a solid electrolyte of solid electrolytic capacitors such as aluminum solid electrolytic capacitors, tantalum solid electrolytic capacitors, niobium solid electrolytic capacitors, and the like, and has low ESR. A highly reliable solid electrolytic capacitor can be provided under high temperature conditions.

In addition, the conductive composition of the present invention has high electrical conductivity and excellent heat resistance, and thus can be suitably used as a positive electrode active material of a battery, a base resin of an anticorrosive coating, etc., in addition to the solid electrolyte of the solid electrolytic capacitor and the conductor of the antistatic material. Can be.

As described above, when the conductive composition of the present invention is used as a solid electrolyte of a conductive material of an antistatic material or a solid electrolytic capacitor, it may be used as it is, but the conductive composition is used as a dispersion liquid dispersed in water or in an aqueous solution, and then obtained by drying. It is more preferable to use the electrically conductive composition as a conductor or a solid electrolyte.

In preparing an antistatic film using the conductive composition of the present invention as a conductor, the dispersion of the conductive composition is applied to the base sheet or the base sheet is immersed in the dispersion of the conductive composition, pulled up, and dried to dry the antistatic film. It is good to form and peel the said film from a base sheet, but rather to peel the antistatic film formed in one side or both sides of a base sheet from the base sheet, and to use it as an antistatic sheet which used the said base sheet as a support material. May be suitable. In addition, to produce an antistatic fabric using the conductive composition of the present invention as a conductor, the dispersion of the conductive composition may be applied to a cloth or the cloth may be dipped in the dispersion of the conductive composition, pulled up, and then dried. And when manufacturing an antistatic sheet and an antistatic cloth as mentioned above, when binder resin is added to the dispersion liquid of the said electroconductive composition, since adhesiveness of the electroconductive composition with respect to a base material sheet or cloth can be improved, it is preferable. Thus, adding a binder to the dispersion liquid of a conductive composition is also preferable when using a conductive composition as a solid electrolyte of a solid electrolytic capacitor.

As the above binder resin, for example, polyurethane, polyester, acrylic resin, polyamide, polyimide, epoxy resin, polyacrylonitrile resin, polymethacrylonitrile resin, polystyrene resin, novolak resin, silane coupling agent These etc. are mentioned, Especially polyester, polyurethane, an acrylic resin, etc. are preferable. Moreover, when sulfone groups are added like sulfonated polyacryl, sulfonated polyvinyl, and sulfonated polystyrene, since electroconductivity of an electroconductive composition can be improved, it is more preferable.

And an antistatic resin is obtained by adding this binder resin or other resin to the dispersion of the said electrically conductive composition, and drying. In addition, when using an electroconductive composition as a solid electrolytic capacitor, a solid electrolytic capacitor can be produced as shown below.

First, when the conductive composition of the present invention is used as a solid electrolyte such as a tantalum solid electrolytic capacitor, a niobium solid electrolytic capacitor, or an aluminum laminated solid electrolytic capacitor, an anode made of a porous body of valve metals such as tantalum, niobium, and aluminum, and these valve metals After repeating the process of immersing the capacitor element having the dielectric layer composed of an oxide film of the conductive composition in the dispersion of the conductive composition of the present invention, and drying it, a solid electrolyte layer made of the conductive composition is formed, and then carbon paste and silver paste are attached. By drying after drying, solid electrolytic capacitors, such as a tantalum solid electrolytic capacitor, a niobium solid electrolytic capacitor, and an aluminum laminated solid electrolytic capacitor, can be manufactured.

For example, a non-iron salt organic sulfonate is used as a dopant, and the capacitor element is immersed and taken out in a liquid containing a polymerizable monomer and an oxidizing agent, followed by polymerization at room temperature, followed by immersion in water. After removing, washing and drying to synthesize the conductive polymer, the process of immersing all of them in the dispersion of the conductive composition of the present invention and taking out and drying may be repeated to form a solid electrolyte layer made of the conductive composition of the present invention. It may be in the reverse form.

The tantalum solid electrolytic capacitor, niobium solid electrolytic capacitor, aluminum laminated solid electrolytic capacitor, and the like can also be produced by covering the device covered with the conductive composition with carbon paste and silver paste in this manner and then externally covering the device.

In addition, when using the electroconductive composition of this invention as a solid electrolyte of an aluminum wound solid electrolytic capacitor, the anode of which the dielectric layer was formed by carrying out the chemical conversion treatment after etching the surface of an aluminum foil. A lead terminal is attached to the cathode, and a lead terminal is attached to the cathode made of aluminum foil, and the anode and the cathode with the lead terminal are wound through a separator to produce a capacitor element, and the capacitor element is a dispersion of the conductive composition of the present invention. After immersed in and taken out, it is dried, and after drying, it is immersed in pure water in order to remove the electroconductive composition which is not contained in the pores formed by the etching of aluminum foil, and it is dried, these After repeating the operation, it is possible to produce an aluminum wound solid electrolytic capacitor by packaging with an exterior material.

(Example)

Although an Example is given to the following and this invention is demonstrated to it further more concretely, this invention is not limited only to what was illustrated in these Examples. In addition, the% at the time of showing a density | concentration or usage-amount in the following example etc. is% by a mass reference | standard unless the reference | standard is specifically added.

Example  One

600 g of a 4% aqueous solution of a phenol sulfonic acid novolak resin (lotEW00130 (trade name) manufactured by Konishigaku Co., Ltd., number average molecular weight 60,000, R is hydrogen) having a repeating unit represented by the formula (1) was added to a 1L stainless steel container. 0.3 g of ferrous sulfate and hexahydrate were added, and 4 mL of 3,4-ethylenedioxythiophene was slowly added dropwise thereto. It stirred with the stirring blade made of stainless steel, and attached the anode to the container, the cathode was attached to the base of the stirring blade, and electrolytic oxidation polymerization was performed for 18 hours by the constant current of 1 mA / cm <2>. After diluting 6 times with water after the said electrolytic oxidation polymerization, dispersion processing was performed for 30 minutes with the ultrasonic homogenizer (the Nippon Seiki company make, US-T300 (brand name)). Then, 100 g of cation exchange resin Amberlite 120B (brand name) made by organo company was added, and it stirred with the stirrer for 1 hour. Subsequently, the result was filtered with filter paper No. 131 manufactured by Toyo Rossi Co., and the treatment with the cation exchange resin and filtration were repeated three times to remove all cations such as iron ions in the liquid. The ratio of 3,4-ethylenedioxythiophene of the phenol sulfonic acid novolak resin serving as the dopant in the electrolytic oxidation polymerization and the polymerizable monomer is a phenol sulfonic acid novolak resin in a mass ratio: 3,4-ethylenedioxine. Citifen = 1: 0.2.

The solution after the above treatment was passed through a filter having a pore diameter of 1 µm, and the passage solution was treated with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Zartoritus Co., Ltd., molecular weight fraction 50,000), and the glass low molecular weight component in the liquid was treated. Removed. The liquid after this treatment was diluted with water to adjust the concentration to 3%, and 4 g of dimethyl sulfoxide (about 330% of dimethyl sulfoxide relative to the conductive polymer) was added as a high boiling point solvent to 40 g of the 3% liquid, thereby dispersing the conductive composition. Obtained. Content of sulfuric acid in this dispersion liquid was measured by ion chromatograph DX120 (brand name) by a Dionex company, and content of sulfuric acid was 25 ppm.

Example  2

Addition of dimethyl sulfoxide, etc., except that 0.05 g of ferrous sulfate and heptahydrate were added to 600 g of a 3% aqueous solution of sulfonated polyester [Plastics Z-561 (trade name) manufactured by Kogagaku Kogyo Co., Ltd., number average molecular weight 27,000] The same operation as in Example 1 was carried out to obtain a dispersion of the conductive composition. The content of sulfuric acid in this dispersion was measured in the same manner as in Example 1, and the content of sulfuric acid was 22 ppm.

Example  3

A dispersion liquid of the conductive composition was obtained in the same manner as in Example 1, such as addition of dimethyl sulfoxide, except that 600 g of a 4% aqueous solution of polystyrene sulfonic acid (manufactured by Teika Co., Ltd., number average molecular weight 100,000) was used. When content of sulfuric acid in this dispersion liquid was measured like Example 1, content of sulfuric acid was 26 ppm.

Example  4

Dimethyl sulfoxide except for using 600 g of a 4% aqueous solution of a phenol sulfonic acid novolak resin having a repeating unit represented by the formula (1), lotEG0727 (trade name) manufactured by Konishigaku Co., Ltd., a number average molecular weight of 20,000, wherein R is hydrogen) The same operation as in Example 1 was carried out, such as addition of, to obtain a dispersion of the conductive composition. When content of sulfuric acid in this dispersion liquid was measured like Example 1, content of sulfuric acid was 27 ppm.

Example  5

The dispersion of the conductive composition was carried out in the same manner as in Example 3, except that 0.4 g of naphthalene sulfonic acid (33% of naphthalene sulfonic acid relative to the conductive polymer) was added as an organic acid having a cyclic structure instead of the high boiling point dimethyl sulfoxide. Obtained. When content of sulfuric acid in this dispersion liquid was measured like Example 1, content of sulfuric acid was 26 ppm.

Example  6

Conductive composition was carried out in the same manner as in Example 3, except that 0.5 g of anthraquinone sulfonic acid (42% of anthraquinone sulfonic acid relative to the conductive polymer) was added as an organic acid having a cyclic structure instead of the dimethyl sulfoxide of the high boiling point solvent. A dispersion of was obtained. When content of sulfuric acid in this dispersion liquid was measured like Example 1, content of sulfuric acid was 26 ppm.

Example  7

The dispersion of the conductive composition was carried out in the same manner as in Example 3, except that 0.5 g (42% phenol sulfonic acid relative to the conductive polymer) of phenol sulfonic acid was added as an organic acid having a cyclic structure in place of the dimethyl sulfoxide of the high boiling point solvent. Obtained. When content of sulfuric acid in this dispersion liquid was measured like Example 1, content of sulfuric acid was 26 ppm.

Comparative example  One

200 g of a 4% aqueous solution of the same phenol sulfonic acid novolak resin (number average molecular weight 60,000) as used in Example 1 was placed in a container having a volume of 1 L, 2 g of ammonium persulfate was added, followed by stirring with a stirrer to dissolve. 3 mL of 3, 4- ethylene dioxythiophene was dripped slowly, stirring continuously, and the chemical oxidation polymerization of 3, 4- ethylene dioxythiophene was performed over 24 hours.

After diluting with water four times after the above chemical oxidation polymerization, dispersion treatment was performed for 30 minutes with an ultrasonic homogenizer (US-T300 (trade name) manufactured by Nippon Seika Co., Ltd.). Then, 100 g of cation exchange resin Amberlite 120B (brand name) made by organo company was added, and it stirred with the stirrer for 1 hour. Then, it filtered by filter paper No.131 by Toyo Rossi Co., and the process and filtration by this cation exchange resin were repeated 3 times, and all the cation components in a liquid were removed.

The liquid after the said process was made to pass through the filter of 1 micrometer of pore diameters, and the pass liquid was processed with the ultrafiltration apparatus (Vivaflow200 (brand name) made from Zartorius, molecular weight fraction 50,000), and the glass low molecular component of the liquid was removed. The liquid after this treatment was diluted with water to adjust the concentration to 3%, and 4 g of dimethyl sulfoxide was added to 40 g of the 3% liquid to obtain a dispersion of the conductive composition. When the content of sulfuric acid in the dispersion was measured in the same manner as in Example 1, the content of sulfuric acid was 123 ppm.

Comparative example  2

A dispersion of the conductive composition was obtained in the same manner as in Example 1 except that 4 g of dimethyl sulfoxide was not added. In addition, since this dispersion liquid does not add the dimethyl sulfoxide of a high boiling point solvent, it should express exactly as a dispersion liquid of a conductive polymer, but the dispersion liquid of this comparative example 2 also suited the dispersion liquid of the electrically conductive composition of Examples 1-7 and Comparative Example 1 for convenience. Expressed as a dispersion of the conductive composition. And content of sulfuric acid in this dispersion liquid was measured like Example 1, and content of sulfuric acid was 22 ppm.

[Evaluation as Conductive Composition]

50 microliters of the dispersion liquid of the electroconductive composition of the said Examples 1-7 and Comparative Examples 1-2 was dripped on the glass plate of 2.8cm x 4.8cm, respectively, and it was made uniform with the bar coater of No.8, and then it is 10 minutes at 60 degreeC. Dried, and then dried at 150 ° C. for 10 minutes to form a sheet of the conductive composition on a glass plate, and the conductivity of the sheet of the conductive composition was measured at room temperature (about 25 ° C.) according to JISK 7194 according to JISK 7194. It measured by [MCP-T600 (brand name) by Mitsubishi Chemical Corporation. The results are shown in Table 1 below. In addition, the measurement is performed with respect to 5 points of each sample, and the numerical value shown in following Table 1 shows the average value of the 5 points, rounds off below the decimal point, and is shown.

As shown in the said Table 1, Examples 1-7 were high in electroconductivity and were excellent in electroconductivity compared with Comparative Examples 1-2. That is, Examples 1 to 7 in which the conductive polymer was synthesized by the electrolytic oxidation polymerization method had higher electrical conductivity than the Comparative Example 1 in which the conductive polymer was synthesized by the chemical oxidation polymerization method, and had excellent conductivity, and also had a high boiling point solvent or a cyclic structure. The conductivity was higher than that of Comparative Example 2 in which no organic acid was added, and the conductivity was excellent.

Subsequently, after measuring the electrical conductivity with respect to each sheet of the conductive compositions of Examples 1 to 7 and Comparative Examples 1 and 2, each sheet was allowed to stand for 100 hours in a 150 ° C. thermostatic bath, and then the respective electrical conductivity was taken out as described above. The same measurement was made. The results are shown in Table 2 below. However, about electrical conductivity, it is represented by the retention of the electrical conductivity after standing for 100 hours at 150 degreeC.

In addition, the retention of conductivity is divided by the initial conductivity (conductivity shown in Table 1) after the elapse of 100 hours at 150 ° C. and expressed as a percentage (%). If this is expressed as an equation, it becomes as follows. The higher the retention rate, the less likely the reduction of the electrical conductivity with respect to heat, indicating that the heat resistance is excellent.

As shown in the said Table 2, Examples 1-7 had the high retention of the electrical conductivity after storage at high temperature, and were excellent in heat resistance compared with Comparative Examples 1-2.

[Evaluation as Antistatic Film]

Example  8-12 and Comparative example  3 to 4

The sulfonated polyester resin [Plastics Z-561 (trade name) manufactured by Kogagaku Kogyo Co., Ltd.] was dispersed with respect to the conductive polymer in the dispersion liquid of the conductive compositions of Examples 1 to 4 and Example 7 and Comparative Examples 1 and 2. 50 microliters of the dispersion liquid containing the said sulfonated polyester resin was dripped on the 2.8 cm x 4.8 cm polyethylene sheet after adding and stirring so that it might become about 150%, respectively, After making it uniform with the bar coater of 8, it dried for 10 minutes at 60 degreeC, and then it dried for 10 minutes at 150 degreeC, and produced the antistatic film which makes each electrically conductive composition a conductor.

The surface resistance of the antistatic films of Examples 8 to 12 and Comparative Examples 3 to 4 obtained were measured at a room temperature (about 25 ° C) in accordance with JIS K 7194 according to JIS K 7194, a conductivity meter [MCP-T600 (trade name) manufactured by Mitsubishi Chemical Corporation. ] And the visible light transmittance of wavelength 400nm-700nm was measured by UV-VIS-NIR RECORDING SPECTROPHOTOMETER (UV3100 (brand name) by Shimadzu Corporation) .The result is shown in following Table 3 with the kind of electroconductive composition which used the result. In addition, the measurement is performed with respect to 5 points of each sample, and the numerical value shown in following Table 3 shows the average value of the 5 points, rounds off below the decimal point, and is shown.

As shown in the said Table 3, the antistatic film of Examples 8-12 is smaller in surface resistance than the antistatic film of Comparative Examples 3-4, and can be estimated from the result that electroconductivity is excellent and it is excellent in antistatic function. there was. Moreover, it turned out that the antistatic film of Examples 8-12 has the high visible light transmittance equivalent to the antistatic film of Comparative Examples 3-4, and was excellent in transparency.

[Evaluation as Tantalum Solid Electrolytic Capacitor]

Example  13

The tantalum sintered compact was applied to a voltage of 20 V while being immersed in an aqueous solution of phosphoric acid having a concentration of 0.1% to form a dielectric film by forming an oxide film on the surface of the tantalum sintered compact. Subsequently, the tantalum sintered compact was immersed in an ethanol solution of 3,4-ethylenedioxythiophene having a concentration of 35%, and taken out after 1 minute and left to stand for 5 minutes. Subsequently, an oxidizing agent and dopant solution composed of a mixture of a preliminarily prepared aqueous solution of phenol sulfonic acid butylamine (pH 5) having a concentration of 50% and an aqueous solution of ammonium persulfate having a concentration of 30% in a mass ratio of 1: 1 was mixed. The mixture was taken out after 30 seconds, left at room temperature for 30 minutes, and then heated at 50 ° C. for 10 minutes to conduct polymerization. Thereafter, the tantalum sintered compact was immersed in water and left for 30 minutes, and then taken out and dried at 70 ° C for 30 minutes. After repeating these operations 6 times, it immersed in the dispersion liquid of the electrically conductive composition of Example 1, took out 30 second, and dried at 70 degreeC for 30 minutes. After repeating this operation 3 times, it left for 60 minutes at 150 degreeC, and formed the solid electrolyte layer which consists of electroconductive compositions. Thereafter, the solid electrolyte layer was covered with carbon paste and silver paste to prepare a tantalum solid electrolytic capacitor.

Example  14

A tantalum solid electrolytic capacitor was produced in the same manner as in Example 13 except that the dispersion of the conductive composition of Example 2 was used in place of the dispersion of the conductive composition of Example 1.

Example  15

A tantalum solid electrolytic capacitor was produced in the same manner as in Example 13 except that the dispersion of the conductive composition of Example 3 was used in place of the dispersion of the conductive composition of Example 1.

Example  16

A tantalum solid electrolytic capacitor was produced in the same manner as in Example 13 except that the dispersion of the conductive composition of Example 4 was used instead of the dispersion of the conductive composition of Example 1.

Comparative example  5

A tantalum solid electrolytic capacitor was produced in the same manner as in Example 13 except that the dispersion of the conductive composition of Comparative Example 1 was used in place of the dispersion of the conductive composition of Example 1.

Comparative example  6

A tantalum solid electrolytic capacitor was produced in the same manner as in Example 13 except that the dispersion of the conductive composition of Comparative Example 2 was used instead of the dispersion of the conductive composition of Example 1.

The ESR and the capacitance of the tantalum solid electrolytic capacitors of Examples 13-16 and Comparative Examples 5-6 produced as described above were measured. The results are shown in Table 4 below. In addition, the measuring method of ESR and electrostatic capacity is as showing below. ESR is measured at 25 ° C and 100kHz using an LCR meter (4284A) manufactured by HEWLETT PACKARD, and capacitance is measured at 25 ° C and 120Hz using an LCR meter (4284A) manufactured by HEWLETT PACKARD. Was measured. These measurements are performed about 10 pieces of each sample, and the ESR values and capacitance values shown in Table 4 below are obtained by averaging these 10 values and rounding up to the decimal point.

As shown in Table 4, it was clear that the tantalum solid electrolytic capacitors of Examples 13 to 16 had a smaller ESR, a larger capacitance, and an excellent function as a capacitor than the tantalum solid electrolytic capacitors of Comparative Examples 5 to 6.

Subsequently, ten tantalum solid electrolytic capacitors of Examples 13 to 16 and Comparative Examples 5 to 6 were respectively stored at 125 ° C. for 200 hours, and then ESR and capacitance were measured as described above. The results are shown in Table 5 below.

As shown in Table 5, the tantalum solid electrolytic capacitors of Examples 13 to 16 were smaller in ESR, larger in capacitance, and higher in reliability under high temperature conditions than after storage at high temperatures in comparison with the tantalum solid electrolytic capacitors of Comparative Examples 5 to 6. .

[Evaluation in Aluminum Winding Solid Electrolytic Capacitor]

(Example 17)

After etching the surface of the aluminum foil, a chemical conversion treatment is performed to attach the lead terminals to the anode having the dielectric layer formed thereon, and to attach the lead terminals to the cathode made of aluminum foil. It wound up and produced the capacitor element.

Subsequently, the dispersion liquid of the electrically conductive composition obtained in Example 3 was neutralized with butylamine to pH 5.5, the said capacitor | condenser element was immersed in this liquid, and it took out after 120 second, and dried at 150 degreeC for 30 minutes. After repeating this operation four times, it dried at 150 degreeC for 120 minutes, and formed the solid electrolyte layer which consists of a conductive composition. Then, after condensing the capacitor | condenser element after formation of the said solid electrolyte layer in the aluminum exterior case, it aged by applying a rated voltage of 25V at 130 degreeC, and produced the aluminum winding type solid electrolytic capacitor.

(Example 18)

An aluminum wound solid electrolytic capacitor was produced in the same manner as in Example 17, except that the dispersion liquid of the conductive composition obtained in Example 5 was neutralized to pH 5.5 with 2-methylimidazole.

(Example 19)

An aluminum wound solid electrolytic capacitor was produced in the same manner as in Example 17, except that the dispersion obtained in Example 6 was neutralized to pH 5.5 with 2-methylimidazole.

(Example 20)

An aluminum wound solid electrolytic capacitor was produced in the same manner as in Example 17, except that the dispersion obtained in Example 7 was neutralized with 4-methylimidazole to pH 5.5.

(Comparative Example 7)

An aluminum wound solid electrolytic capacitor was produced in the same manner as in Example 17, except that the dispersion liquid of the conductive composition obtained in Comparative Example 1 was neutralized to pH 5.5 with butylamine.

The ESR and the capacitance of the aluminum wound solid electrolytic capacitors of Examples 17 to 20 and Comparative Example 7 prepared as described above were measured. The results are shown in Table 6 below. In addition, the measuring method of ESR and electrostatic capacity is as showing below. ESR is measured at 25 ° C and 100kHz using the LCR meter (4284A) manufactured by HEWLETT PACKARD. ESR is measured at 25 ° C and 120Hz using the LCR meter (4284A) manufactured by HEWLETT PACKARD. Measured. These measurements are carried out for each of ten samples, and the average values of these ten values are obtained from the ESR values and the capacitance values shown in Table 6 below, and are shown by rounding off the decimal point.

As shown in Table 6, the aluminum wound solid electrolytic capacitors of Examples 17 to 20 became smaller than the aluminum wound solid electrolytic capacitors of Comparative Example 7, which had a smaller ESR, a larger capacitance, and an excellent function as a capacitor. .

Subsequently, 10 aluminum wound solid electrolytic capacitors of Examples 17 to 20 and Comparative Example 7 were each stored at 125 ° C. for 500 hours, and then ESR and capacitance were measured as described above. The results are shown in Table 7 below.

As shown in Table 7 above, the aluminum wound solid electrolytic capacitors of Examples 17 to 20 have a smaller ESR, a higher capacitance, and higher reliability under high temperature conditions than the aluminum wound solid electrolytic capacitors of Comparative Example 7 after storage at high temperatures. Was high.

According to the present invention, it is possible to provide a conductive composition having high transparency, high conductivity and excellent heat resistance. In addition, since the conductive composition of the present invention has high transparency and the conductive polymer is synthesized by electrolytic oxidation polymerization, the content of sulfuric acid root based on the oxidizing agent shown in the conductive polymer synthesized by chemical oxidation polymerization is low, and the remaining sulfate sulfate There is little fall of electroconductivity, transparency fall, etc. which are based on.

Therefore, by using this as a conductor based on the characteristics of the electrically conductive composition of this invention, an antistatic film, an antistatic resin, an antistatic sheet, etc. which are high in transparency, high in electroconductivity, and excellent in heat resistance can be provided. In addition, by using the conductive composition of the present invention having such high conductivity and excellent heat resistance as a solid electrolyte, it is possible to provide a solid electrolytic capacitor having a low ESR and high reliability under high temperature conditions.

Claims (14)

In the presence of a phenol sulfonic acid novolak resin or sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the following formula (1), thiophene or a derivative thereof is stirred in water or in an aqueous solution composed of a mixture of water and a water miscible solvent. A conductive liquid obtained by electrolytic oxidation polymerization in the water or in an aqueous solution in a dispersed state and a high boiling point solvent having a boiling point of 150 ° C. or higher, or an organic acid having a cyclic structure.
(Formula 1)

(In Formula 1, R is hydrogen or methyl group) The method of claim 1,
The thiophene derivative is a dispersion of the conductive composition, characterized in that 3,4-ethylenedioxythiophene. The method of claim 1,
Electrolytic oxidation polymerization was performed in the water containing iron ions, or in aqueous liquid, The dispersion liquid of the electrically conductive composition characterized by the above-mentioned. The method of claim 1,
The high boiling point solvent whose boiling point is 150 degreeC or more is dimethyl sulfoxide, The dispersion liquid of the electrically conductive composition characterized by the above-mentioned. The method of claim 1,
An organic acid having a cyclic structure is an aromatic organic acid, wherein the dispersion of the conductive composition. The method of claim 5, wherein
The aromatic organic acid is a dispersion of the conductive composition, characterized in that at least one selected from the group consisting of phenol sulfonic acid, naphthalene sulfonic acid and anthraquinone sulfonic acid. The method of claim 1,
Further, a binder is contained, The dispersion liquid of the conductive composition characterized by the above-mentioned. In the presence of a phenol sulfonic acid novolak resin or sulfonated polyester or polystyrene sulfonic acid having a repeating unit represented by the following formula (1), thiophene or a derivative thereof is stirred in water or in an aqueous solution composed of a mixture of water and a water miscible solvent. A conductive polymer is obtained in the dispersed state in the water or an aqueous liquid by electrolytic oxidation polymerization, and a high boiling point solvent having a boiling point of 150 ° C. or more or an organic acid having a cyclic structure is added to the dispersion of the obtained conductive polymer. And a method for producing a dispersion of a conductive composition containing a high boiling point solvent having a boiling point of 150 ° C. or higher or an organic acid having a cyclic structure:
(Formula 1)

(In Formula 1, R is hydrogen or methyl group) The method of claim 8,
The thiophene derivative is 3,4-ethylenedioxythiophene, The manufacturing method of the dispersion of the electrically conductive composition characterized by the above-mentioned. The method of claim 8,
Electrolytic oxidation polymerization is performed in the water containing iron ions, or in aqueous liquid, The manufacturing method of the dispersion liquid of the electrically conductive composition characterized by the above-mentioned. The method of claim 8,
The high boiling point solvent whose boiling point is 150 degreeC or more is dimethyl sulfoxide, The manufacturing method of the dispersion liquid of the electrically conductive composition characterized by the above-mentioned. The method of claim 8,
The organic acid which has a cyclic structure is an aromatic organic acid, The manufacturing method of the dispersion liquid of the electrically conductive composition characterized by the above-mentioned. The method of claim 12,
Aromatic organic acid is at least one member selected from the group consisting of phenol sulfonic acid, naphthalene sulfonic acid and anthraquinone sulfonic acid. The method of claim 8,
A method for producing a dispersion of the conductive composition, further comprising a binder.