JP5062738B2 - Conductive composition, method for producing the same, dispersion of conductive composition, and application of conductive composition - Google Patents

Description

  The present invention relates to a conductive composition, a production method thereof, a dispersion of the conductive composition, an antistatic film using the conductive composition as a conductor, an antistatic material such as an antistatic sheet, and the conductive composition. The present invention relates to an application of a conductive composition such as a solid electrolytic capacitor using a solid electrolyte as a solid electrolyte.

  Conductive polymers are used as solid electrolytes for solid electrolytic capacitors such as tantalum solid electrolytic capacitors, niobium solid electrolytic capacitors, aluminum solid electrolytic capacitors, and conductors for antistatic materials due to their high conductivity.

  As the conductive polymer in this application, for example, those synthesized by chemical oxidative polymerization or electrolytic oxidative polymerization of pyrrole or a derivative thereof, thiophene or a derivative thereof, and the like are used. Among those oxidative polymerization methods, electrolytic oxidative polymerization requires expensive equipment, and industrially, it is said that chemical oxidative polymerization that does not require such expensive equipment is suitable. Industrialization is generally performed by chemical oxidative polymerization.

  As a dopant for the chemical oxidative polymerization of pyrrole or a derivative thereof, thiophene or a derivative thereof, organic sulfonic acid is mainly used, and among them, aromatic sulfonic acid is said to be suitable. Transition metals are used. Among them, ferric iron is said to be suitable. Usually, ferric salts of aromatic sulfonic acids are used in chemical oxidative polymerization of pyrrole or its derivatives, thiophene or its derivatives, etc. It is used as an oxidant and dopant agent.

  And among the ferric salts of aromatic sulfonic acids, it is said that ferric salts of toluene sulfonic acid and ferric salts of methoxybenzene sulfonic acid are particularly useful, and conductive polymers using them. It can be synthesized by mixing those oxidizing agent and dopant with pyrrole or a derivative thereof, thiophene or a derivative thereof, and is reported to be simple and suitable for industrialization (Patent Document 1, Patent Document) 2).

  However, a conductive polymer obtained by using ferric toluene sulfonate as an oxidizing agent / dopant does not necessarily have sufficient characteristics in terms of initial resistance value and heat resistance. Conductive polymers obtained using diiron salts as oxidizing agents and dopants have lower initial resistance values and superior heat resistance than conductive polymers using ferric toluenesulfonates. Even so, it was not possible to obtain sufficiently satisfactory characteristics.

  In addition, when the conductive polymer obtained by the chemical oxidative polymerization method is used as the solid electrolyte of the solid electrolytic capacitor, the conductive polymer synthesized by the chemical oxidative polymerization method is usually not soluble in a solvent. It is necessary to form a conductive polymer directly on an element having an anode made of a porous body of a valve metal such as niobium or aluminum and a dielectric layer made of an oxide film of the valve metal.

  However, forming the conductive polymer directly on the element in this way has a problem that it is forced to carry out a very difficult work conditionally, the reproducibility is poor, and the process control becomes very difficult. .

  Based on such a situation, solubilized conductive polymers have been actively studied (Patent Document 3). According to Patent Document 3, a reaction liquid obtained by chemically oxidizing pyrrole with a persulfate in the presence of polycarboxylic acid is rendered alkaline, and then a precipitate formed by adding a water-soluble alcohol is added to an aqueous solution. It has been reported that a dispersion of a polypyrrole-based conductive polymer can be obtained by redispersing in a medium.

  However, the polypyrrole thus obtained has insufficient conductivity, does not have sufficient characteristics to be used as a solid electrolyte for a solid electrolytic capacitor, and is further reduced in resistance as a conductor for an antistatic material. High transparency is demanded.

JP 2003-160647 A JP 2004-265927 A Japanese Patent No. 3515799

  The present invention solves the problems of the prior art relating to the polypyrrole-based conductive polymer as described above, and is synthesized by chemical oxidative polymerization of pyrrole or a derivative thereof, thereby providing high conductivity, high transparency, and Providing conductive polymers with excellent heat resistance, and using them as conductors, providing antistatic materials such as antistatic films and antistatic sheets that are highly conductive and highly transparent, and that are solid An object of the present invention is to provide a solid electrolytic capacitor that is used as an electrolyte and has high reliability under high temperature conditions.

  As a result of intensive studies to solve the above problems, the present inventors have found that pyrrole or a derivative thereof is an organic sulfonate using a specific polysulfonate and an aromatic sulfonate in combination at a specific ratio, and When a conductive polymer is synthesized by oxidative polymerization using sulfate and the pH is adjusted to 1.5 to 4.5 when the dispersion containing the conductive polymer is made into a dispersion having a concentration of 1% by mass. Has found that a conductive composition having high conductivity, high transparency and excellent heat resistance can be obtained, and based on this, the present invention has been completed.

  That is, the present invention is an organic sulfonate composed of a polystyrene sulfonate having a number average molecular weight of 10,000 to 300,000 and an aromatic sulfonate, and is aromatic against the polystyrene sulfonate portion of the polystyrene sulfonate. An organic sulfonate in which the aromatic sulfonic acid part of the aromatic sulfonate is 20 to 50% by mass (that is, the aromatic sulfonic acid part is 20 to 50 parts by mass with respect to 100 parts by mass of the polystyrene sulfonic acid part); A conductive polymer comprising a conductive polymer synthesized by oxidative polymerization of pyrrole or a derivative thereof with persulfate, and having a pH of 1.5 to 4.5 when a dispersion having a concentration of 1% by mass is formed. The present invention relates to a sex composition.

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

  According to the present invention, a conductive composition having high conductivity, high transparency, and excellent heat resistance can be provided. Therefore, an antistatic material such as an antistatic film or an antistatic sheet having high conductivity and high transparency can be provided by using the conductive polymer as a conductor.

  Further, by using the conductive composition as a solid electrolyte, it is possible to provide a solid electrolytic capacitor having high reliability even under high temperature conditions.

  In the present invention, pyrrole or a derivative thereof is oxidatively polymerized using a specific organic sulfonate and a persulfate as described above. As the pyrrole or a derivative thereof, not only pyrrole itself but also, for example, 1-methyl Derivatives of pyrrole such as pyrrole, 1-ethylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-methoxypyrrole, 3,4-dimethylpyrrole, 3,4-dimethoxypyrrole, 3,4-ethylenedioxypyrrole Used.

  In the present invention, an organic sulfonate composed of a polystyrene sulfonate and an aromatic sulfonate functions mainly as a dispersant and a dopant agent in the synthesis of a conductive polymer. In addition to serving as a dispersant in the oxidative polymerization of pyrrole or its derivatives, it also serves as a dopant. Aromatic sulfonates serve as dopant agents that impart conductivity to polymers of pyrrole or its derivatives. Fulfill.

  And as the polystyrene sulfonic acid in the polystyrene sulfonate, those having a number average molecular weight of 10,000 to 300,000 are used. When the polystyrene sulfonate has a number average molecular weight smaller than 10,000, sufficient dispersibility is obtained. If the number average molecular weight of the polystyrene sulfonate is greater than 300,000, the reason is not clear, but sufficient conductivity cannot be obtained. As the polystyrene sulfonate, those having a number average molecular weight of 20,000 to 100,000 are particularly preferred.

  The aromatic sulfonic acid in the aromatic sulfonate is a sulfonic acid having a benzene ring, naphthalene ring, tetralin ring or anthraquinone ring, and specific examples thereof include, for example, paratoluenesulfonic acid, methoxybenzenesulfonic acid, dodecyl. Examples include benzene sulfonic acid, naphthalene sulfonic acid, naphthalene disulfonic acid, naphthalene trisulfonic acid, butyl naphthalene sulfonic acid, tetralin sulfonic acid, phenol sulfonic acid, anthraquinone sulfonic acid, etc., but in particular naphthalene sulfonic acid, naphthalene disulfonic acid, naphthalene Trisulfonic acid, tetralinsulfonic acid, and phenolsulfonic acid are preferable because high conductivity is obtained.

  Examples of the salts in these polystyrene sulfonates and aromatic sulfonates include sodium salts, potassium salts, lithium salts, magnesium salts, calcium salts, strontium salts, and barium salts.

  In the present invention, the aromatic sulfonic acid portion of the aromatic sulfonate is 20 to 50% by mass based on the polystyrene sulfonic acid portion of the polystyrene sulfonate having a number average molecular weight of 10,000 to 300,000. This is based on the following reasons. That is, when the aromatic sulfonic acid portion is less than 20% by mass relative to the polystyrene sulfonic acid portion, the amount of aromatic sulfonic acid incorporated into the polymer (polymer) as a dopant is small, so that sufficient conductivity is obtained. Further, when the aromatic sulfonic acid part is more than 50% by mass based on the polystyrene sulfonic acid part, it becomes particles and cannot be used as a dispersion. Particularly preferred as the amount of the aromatic sulfonic acid moiety relative to the polystyrene sulfonic acid moiety is that the aromatic sulfonic acid moiety is 25 to 45% by mass based on the polystyrene sulfonic acid moiety.

  In the present invention, persulfate plays a role as an oxidizing agent, but the persulfate is not particularly limited, and ammonium persulfate, sodium persulfate, potassium persulfate, and the like can be used. In particular, ammonium persulfate is preferable because it does not contain metal elements such as sodium and potassium.

  The oxidative polymerization of pyrrole or a derivative thereof using the organic sulfonate or persulfate is preferably performed at 0 to 50 ° C. in the presence of water. When the temperature is lower than 0 ° C., precipitation occurs and polymerization does not proceed. When the temperature is higher than 50 ° C., the reaction proceeds dramatically, and thus the side reaction occurs, resulting in poor conductivity of the obtained conductive polymer. There is a risk.

  The aqueous dispersion containing a conductive polymer obtained by oxidative polymerization of pyrrole or a derivative thereof as described above is a strong acid, and the pH at a concentration of 1% by mass is 1 or less. And the conductive polymer obtained by drying the aqueous dispersion of such a conductive polymer has low electrical conductivity, and does not have sufficient electrical conductivity.

  Therefore, in the present invention, after removing low molecular components such as cations and persulfate from the aqueous dispersion of the conductive polymer after the oxidative polymerization as described above, ammonia and amines such as methylamine, ethylamine , Propylamine, butylamine, and imidazoles such as 2-methylimidazole are added in an arbitrary amount so that the pH of the dispersion when adjusted to a concentration of 1% by mass is 1.5 to 4.5. The composition is dried and dried to obtain a conductive composition having high conductivity. In addition, what is obtained by oxidative polymerization of pyrrole or a derivative thereof is a pyrrole-based conductive polymer. In the present invention, as described above, the pH is adjusted by adding ammonia, amines, imidazoles, or the like. Therefore, in addition to the conductive polymer, it contains what is derived from the above pH improver, so it is called a conductive composition.

  In the present invention, the pH of the 1% by mass dispersion of the above conductive composition is 1.5 to 4.5 because the pH is 1.5 or more, and the conductivity obtained by drying. The conductivity of the composition is improved. However, when the pH is higher than 4.5, it becomes a dedope state, and the conductivity of the conductive composition obtained by drying deteriorates. The pH of the 1% by mass dispersion is preferably 2 or more and preferably 4 or less within the above range. When used as a solid electrolyte of an aluminum capacitor or a conductor of an antistatic material, it is difficult to handle if it is a strong acid, but a pH of 1.5 to 4.5 is sufficient.

  The conductive composition of the present invention obtained as described above becomes a solid content in the final usage form, but in its use, it is easy to handle by dispersing in water and keeping it in a dispersion state, The concentration at that time is preferably 1 to 40% by mass. This is because when the concentration of the dispersion of the conductive composition is lower than 1% by mass, it becomes difficult to obtain a conductive composition having high conductivity when dried, and when it is higher than 40% by mass, the viscosity is high. This is because it becomes too difficult to handle. And the density | concentration of the dispersion liquid of this electroconductive composition is more preferably 4 mass% or more within the said range, and 10 mass% or less is more preferable.

  Since the water-soluble solvent can be mixed in the dispersion liquid of the conductive composition of the present invention, the selection range of the binder resin is expanded. Of course, non-water-soluble resins can also be blended. By expanding the selection range of the binder resin, it is possible to apply the dispersion liquid of the conductive composition to the sheet or cloth to improve the handleability and adhesion when performing antistatic processing on the sheet or cloth. .

  In addition, the dispersion liquid of the conductive composition is Li, Na, K, Mg, Ca when the total solid content (solid content: residue when dried at 105 ° C. for 2 hours) is 1% by mass. The total content of metal elements such as Sr, Ba, Ti, Cr, Mn, Fe, Ni, Cu, Ce, Ag, Zn, Cd, and Al is preferably 100 ppm or less. Thus, the heat resistance of an electroconductive composition can be improved by making the total content of the metal element in an electroconductive composition into the said content 100 ppm or less.

  The polystyrene sulfonate used in the present invention can be obtained, for example, as follows.

  It can be obtained by dissolving sodium styrenesulfonate in pure water, for example, and polymerizing it in the presence of an oxidizing agent such as hydrogen peroxide, persulfate, or transition metal. It can be adjusted to a specific molecular weight by adjusting the amount.

  Then, after adding and dissolving a specific amount of aromatic sulfonate in the aqueous solution of polystyrene sulfonate obtained as described above, persulfate as an oxidizing agent, and optionally a small amount of transition metal The oxidative polymerization reaction proceeds by adding the monomer pyrrole or a derivative thereof while adding and mixing the salt. Since heat is generated at this time, it is necessary to cool with water or ice and keep the reaction temperature at 0 to 50 ° C. as described above. In this way, a coarse dispersion of the conductive composition is obtained. Next, the cations may be removed immediately with a cation exchange resin at this stage, but it is better to remove the cations with a cation exchange resin after dispersing with a disperser such as an ultrasonic homogenizer or a planetary ball mill. This is preferable because the amount of metal element to be reduced is reduced. Then, after removing low molecular components such as persulfate by ethanol precipitation method or ultrafiltration method, add ammonia, amines, imidazoles, etc. The conductive composition of the present invention can be obtained in the state of an aqueous dispersion by adjusting to 1.5 to 4.5 under specific conditions.

  The conductive composition of the present invention obtained by removing water from the aqueous dispersion as described above has high conductivity, high transparency, and excellent heat resistance. It can be used as an antistatic material as described above, and since it has high conductivity and excellent heat resistance, tantalum solid electrolytic capacitors, niobium solid electrolytic capacitors, aluminum solid electrolytic capacitors, etc. Thus, it is possible to provide a solid electrolytic capacitor that is preferably used as a solid electrolyte of the solid electrolytic capacitor and has high reliability under high temperature conditions.

  And when applying the electrically conductive composition of this invention for the above uses, it is preferable to use the dispersion liquid of the electrically conductive composition obtained as mentioned above.

  For example, when applied to an antistatic material, the dispersion of the conductive composition can be applied to a sheet (including a film) or cloth as it is for antistatic processing, but it is better to add a binder resin. This is preferable because adhesion to a substrate such as a sheet or cloth is improved. Examples of such binder resins include polyurethane, polyester, acrylic resin, polyamide, polyimide, epoxy resin, polyacrylonitrile resin, polymethacrylonitrile resin, polystyrene resin, novolac resin, etc. An acrylic resin or the like is preferable.

  When the conductive composition of the present invention is applied 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 valve metal such as tantalum, niobium, or aluminum; A capacitor element composed of a dielectric layer made of an oxide film of the valve metal formed on the anode is immersed in a dispersion liquid of the conductive composition, and the operation of lifting and drying is repeated to form the conductive composition. After forming the solid electrolyte layer, a carbon paste and a silver paste are applied, and then packaged to produce a tantalum solid electrolytic capacitor, a niobium solid electrolytic capacitor, an aluminum laminated solid electrolytic capacitor, and the like.

  Alternatively, an oxidizing agent such as an organic sulfonic acid ferric alcohol solution and a monomer alcohol solution such as an alcohol solution of 3,4-ethylenedioxythiophene previously mixed in a solution prepared in advance After immersing and pulling up the capacitor element having a dielectric layer, it is subjected to oxidative polymerization at room temperature, immersed in pure water, pulled up, washed, and dried to synthesize a conductive polymer, and then the present invention. The solid electrolyte layer made of the conductive composition may be formed by repeating the steps of immersing in the dispersion of the conductive composition, lifting and drying, and vice versa. Thus, after covering the element covered with the conductive composition with carbon paste or silver paste, it can be packaged to produce a tantalum solid electrolytic capacitor, a niobium solid electrolytic capacitor, an aluminum laminated solid electrolytic capacitor, or the like. .

  When the conductive composition of the present invention is used as a solid electrolyte of an aluminum-wound solid electrolytic capacitor, the surface of the aluminum foil that constitutes the anode is etched and then subjected to chemical conversion to form an aluminum oxide film. A lead terminal is attached to an anode of a capacitor element formed by forming a dielectric layer, and a lead terminal is attached to a cathode made of aluminum foil, and the anode with the lead terminal and the cathode are wound through a separator. The produced capacitor element is immersed in the dispersion liquid of the conductive composition of the present invention, pulled up, dried, and then the conductive composition portion not formed in the pores formed in the aluminum foil by the above etching is removed. Impregnate in water, pull up and dry. This operation is repeated many times to form a desired solid electrolyte layer made of a conductive composition and then packaged with an exterior material to produce an aluminum wound solid electrolytic capacitor.

  In addition, since the conductive composition of the present invention has high conductivity and excellent heat resistance, by utilizing these characteristics, in addition to the solid electrolyte of the solid electrolytic capacitor and the conductor of the antistatic material, It can also be suitably used as a positive electrode active material for batteries, a base resin for anti-corrosion paints, and the like.

  Next, the present invention will be described more specifically with reference to examples. However, this invention is not limited only to those Examples. In the following examples and the like,% indicating concentration is mass%.

Example 1
200 g of a 20% aqueous solution of polystyrene sulfonate (trade name: PS-5, manufactured by Tosoh Corporation) having a number average molecular weight of 60,000 was placed in a 2 L beaker, 30 g of ammonium persulfate was added, and the mixture was dissolved by stirring with a stirrer. . Thereafter, 15 g of sodium naphthalenesulfonate was added, adjusted to 1,000 g with pure water, and then dissolved by stirring with a stirrer. The beaker was cooled with ice, 18 ml of a 100% pyrrole solution was slowly added dropwise with stirring with a stirrer, and a reaction (oxidative polymerization) was performed for 3 hours while maintaining a temperature of 10 to 30 ° C.

  After completion of the reaction, 100 g of cation exchange resin Amberlite 120B (trade name, manufactured by Organo) was added, and the mixture was stirred for 1 hour with a stirrer and then filtered three times to remove all cations. Thereafter, 9 L of pure water was added to this solution, and the operation of concentrating to 800 ml with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000) was repeated four times to remove low molecular components. . Thereafter, 10 g of 2-methylimidazole was added and dissolved, and then adjusted with solid water so that the solid content (residual amount when dried at 105 ° C. for 2 hours) was 6%. A dispersion was obtained. The naphthalenesulfonic acid portion of sodium naphthalenesulfonate relative to the polystyrenesulfonic acid portion of sodium polystyrenesulfonate in Example 1 was 38% by mass.

  This conductive composition is diluted with pure water so as to have a concentration of 1%, and then Li, Na, K, Mg, Ca, Sr, Ba, Ti, Cr, Mn are obtained using an ICP emission spectroscopic analyzer (manufactured by Rigaku Corporation). , Fe, Ni, Cu, Ce, Ag, Zn, Cd, Al content was measured, the total content of these metal elements was 12 ppm, and the pH of the 1% dispersion of the above conductive composition Was 2.2.

Example 2
200 g of an aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 20,000 (trade name: PS-1 manufactured by Tosoh Corporation) was placed in a container, 30 g of ammonium persulfate was added thereto, and the mixture was dissolved by stirring with a stirrer. Next, 12 g of sodium naphthalene sulfonate was added, adjusted to 1,000 g with water, and then dissolved by stirring with a stirrer. The periphery of the reaction vessel was cooled with ice, and while stirring with a stirrer, 18 ml of a 100% solution of pyrrole was slowly dropped, and a reaction (oxidative polymerization) was performed for 3 hours while maintaining a temperature of 10 to 30 ° C.

  After completion of the reaction, 100 g of cation exchange resin Amberlite 120B (trade name, manufactured by Organo) was added, and the mixture was stirred for 1 hour with a stirrer and then filtered three times to remove all cations. Thereafter, 9 L of water was added to the filtrate, and the operation of concentrating to 800 ml with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000) was repeated four times to remove low molecular components. Thereafter, 10 g of 2-methylimidazole was added and dissolved, and then water was added to adjust the solid content concentration to 6% to obtain a dispersion of a conductive composition. The naphthalenesulfonic acid portion of sodium naphthalenesulfonate relative to the polystyrenesulfonic acid portion of sodium polystyrenesulfonate in Example 2 was 30% by mass.

  Water was added to the dispersion of the conductive composition to dilute the solid content to 1%, and the amount of metal elements was measured in the same manner as in Example 1. The total content of metal elements was 10 ppm, The pH was 2.1.

Example 3
A conductive composition dispersion was obtained in the same manner as in Example 1 except that 12 g of sodium tetralinsulfonate was used instead of 15 g of sodium naphthalenesulfonate. The tetralin sulfonic acid moiety of sodium tetralin sulfonate relative to the polystyrene sulfonic acid moiety of sodium polystyrene sulfonate in Example 3 was 30% by mass.

  Water was added to the dispersion of the conductive composition to dilute the solid content concentration to 1%, and the amount of metal elements was measured in the same manner as in Example 1. As a result, the total content of metal elements was 13 ppm, The pH was 2.0.

Example 4
A dispersion of a conductive composition was obtained in the same manner as in Example 1 except that 15 g of disodium naphthalene disulfonate was used instead of 15 g of sodium naphthalenesulfonate. The naphthalene disulfonic acid portion of disodium naphthalene disulfonate relative to the polystyrene sulfonic acid portion of sodium polystyrene sulfonate in Example 4 was 36% by mass.

  When water was added to the dispersion of the conductive composition to dilute the solid content concentration to 1% and the amount of metal elements was measured in the same manner as in Example 1, the total content of metal elements was 9 ppm. The pH was 2.1.

Example 5
A dispersion of a conductive composition was obtained in the same manner as in Example 1 except that 17 g of trisodium naphthalene trisulfonate was used instead of 15 g of sodium naphthalene sulfonate. The naphthalene trisulfonic acid portion of trisodium naphthalene trisulfonate relative to the polystyrene sulfonic acid portion of sodium polystyrene sulfonate in Example 5 was 40% by mass.

  When water was added to the dispersion of the conductive composition to dilute the solid content concentration to 1% and the amount of metal elements was measured in the same manner as in Example 1, the total content of metal elements was 9 ppm. The pH was 2.2.

Example 6
A conductive composition dispersion was obtained in the same manner as in Example 1 except that 12 g of sodium phenolsulfonate was used instead of 15 g of sodium naphthalenesulfonate. In Example 6, the phenolsulfonic acid portion of sodium phenolsulfonate relative to the polystyrenesulfonic acid portion of sodium polystyrenesulfonate was 30% by mass.

  When water was added to the dispersion liquid of the conductive composition to dilute the solid concentration to 1% and the amount of metal elements was measured in the same manner as in Example 1, the total content of metal elements was 11 ppm. The pH was 2.0.

Example 7
After adding 9 L of water and concentrating to 800 ml four times with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000), concentrating to 200 ml finally, A conductive composition dispersion was obtained in the same manner as in Example 1 except that 600 ml was added. Since the structure of the organic sulfonate in Example 7 is the same as that of Example 1, the naphthalene sulfonic acid part of sodium naphthalene sulfonate with respect to the polystyrene sulfonic acid part of sodium polystyrene sulfonate has the same mass as in Example 1. The standard is 38%.

  Water was added to the dispersion of the conductive composition to dilute the solid content concentration to 1%, and the amount of metal elements was measured in the same manner as in Example 1. As a result, the total content of metal elements was 13 ppm, The pH was 2.2.

Example 8
A conductive composition dispersion was obtained in the same manner as in Example 1 except that 2-methylimidazole was added until the pH under the above conditions reached 3.0. Since the structure of the organic sulfonate in Example 8 is the same as that in Example 1, the naphthalene sulfonic acid portion of sodium naphthalene sulfonate with respect to the polystyrene sulfonic acid portion of sodium polystyrene sulfonate is based on mass as in Example 1. It was 38%.

  Water was added to the dispersion of the conductive composition to dilute the solid content to 1%, and the amount of metal elements was measured in the same manner as in Example 1. The total content of metal elements was 10 ppm, The pH was 3.0 as described above.

Comparative Example 1
A dispersion of the conductive composition was obtained in the same manner as in Example 1 except that 2-methylimidazole was added until the pH under the above condition was 5.3.

  Water was added to the dispersion of the conductive composition to dilute the solids concentration to 1%, and the amount of metal elements was measured in the same manner as in Example 1. The total content of metal elements was 12 ppm, Moreover, pH was 5.3 as mentioned above, and was outside the range of pH 1.5-4.5 prescribed | regulated by this invention.

Comparative Example 2
Example 1 to the point where an ultrafiltration device is used using 200 g of a 20% aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 2,000 instead of 200 g of a 20% aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 60,000. The same operation was performed. However, since the reaction product is in the form of particles, it is impossible to perform desalting with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 5,000).

Comparative Example 3
A conductive composition in the same manner as in Example 1 except that 200 g of a 20% aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 60,000 was used instead of 800 g of a 5% aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 800,000. A dispersion was obtained.

  When water was added to the dispersion liquid of the conductive composition to dilute the solid concentration to 1% and the amount of metal elements was measured in the same manner as in Example 1, the total content of metal elements was 11 ppm. The pH was 2.0.

Comparative Example 4
A conductive composition dispersion was obtained in the same manner as in Example 1 except that 10 g of 2-methylimidazole was not added.

  When water was added to the dispersion of the conductive composition to dilute the solid content concentration to 1% and the amount of metal elements was measured in the same manner as in Example 1, the total content of metal elements was 9 ppm. The pH was 1.0, which was outside the range of pH 1.5 to 4.5 defined in the present invention.

Comparative Example 5
Instead of 200 g of a 20% aqueous solution of sodium polystyrene sulfonate having a number average molecular weight of 60,000, 40 g of gum arabic having a number average molecular weight of 100,000 (manufactured by San-Ei Gen FFI Co., Ltd.) was used, except that 3 g of 2-methylimidazole was added. Obtained the dispersion liquid of the electrically conductive composition like Example 1. FIG.

  Water was added to the dispersion of the conductive composition to dilute the solids concentration to 1%, and the amount of metal elements was measured in the same manner as in Example 1. The total content of metal elements was 12 ppm, The pH was 2.3.

Comparative Example 6
A conductive composition dispersion was obtained in the same manner as in Example 1 except that the amount of sodium naphthalenesulfonate added was changed from 15 g to 4 g.

  The naphthalenesulfonic acid portion of sodium naphthalenesulfonate relative to the polystyrenesulfonic acid portion of sodium polystyrenesulfonate in Comparative Example 6 was 10% on a mass basis, and was outside the range of 20 to 50% defined in the present invention.

Comparative Example 7
The amount of sodium naphthalene sulfonate added was changed from 15 g to 40 g, and the same operation as in Example 1 was performed until the step of using the ultrafiltration device. However, the reaction product was gelled, and desalting could not be performed with an ultrafiltration device (Vivaflow 200 (trade name) manufactured by Sartorius, molecular weight fraction 50,000).

  In addition, the naphthalene sulfonic acid portion of sodium naphthalene sulfonate relative to the polystyrene sulfonic acid portion of sodium polystyrene sulfonate in Comparative Example 7 was 100% on a mass basis, and was outside the range of 20 to 50% defined in the present invention. .

  Next, the electrical conductivity was investigated about what obtained the electroconductive composition like the said Examples 1-8 and the comparative examples 1 and 3-6. The results are shown in Table 1. The measurement method is as follows.

Conductivity measurement method:
Polyvinyl alcohol 1.5g was added with respect to 100g of each dispersion liquid of each electrically conductive composition of Examples 1-8 and Comparative Examples 1 and 3-6, and it melt | dissolved completely by stirring with a stirrer. Thereafter, dispersion treatment was performed for 2 minutes with a US-T300 type ultrasonic device manufactured by Nippon Seiki Seisakusho Co., Ltd. Filter through 131 filter paper. 50 μl of the filtrate was dropped on a 2.8 cm × 4.8 cm glass plate. After uniformizing with 8 bar coater, it was dried with a dryer at 60 ° C. for 30 minutes. After this operation was repeated once more, the electrical conductivity was measured at room temperature (about 25 ° C.) with a 4-probe conductivity meter [MCP-T600 (trade name) manufactured by Mitsubishi Chemical Corporation] according to JIS K 7194. In addition, measurement is performed for each sample for five points, and the numerical values shown in Table 1 are obtained by calculating an average value of the five points and rounding off the decimals. The same applies to the following.

  As shown in Table 1, the conductive compositions of Examples 1 to 8 were higher in electrical conductivity and superior in conductivity than the conductive compositions of Comparative Examples 1 and 3 to 6.

  Next, the samples of Examples 1 to 8 and Comparative Examples 1 and 3 to 6 after the above conductivity measurement (polypyrrole conductive composition film) were placed in a thermostatic bath at 150 ° C. together with the ceramic plate, and 24 The plate was taken out after time storage, the conductivity of the conductive composition film was measured in the same manner as described above, and the conductivity retention after storage was examined based on the measurement result. The results are shown in Table 2.

  The conductivity retention is divided by the initial conductivity (conductivity listed in Table 1) and expressed as a percentage (%). The equation for calculating the conductivity retention is as follows.

  As shown in Table 2, Examples 1 to 8 had higher electrical conductivity retention after storage at high temperature (150 ° C.) and superior heat resistance than Comparative Examples 1 and 3 to 6.

[Evaluation as a solid electrolytic capacitor]
Next, evaluations in the case where the conductive composition of the present invention is used as a solid electrolyte of a solid electrolytic capacitor are shown in Examples 9 to 16 below.

Example 9
A tantalum sintered body is subjected to chemical conversion treatment by applying a voltage of 20 V in a state where the tantalum sintered body is immersed in a phosphoric acid aqueous solution having a concentration of 0.1%, and a dielectric made of a tantalum oxide film on the surface of the tantalum sintered body. A layer was formed.

  Next, the tantalum sintered body is immersed in a 3,4-ethylenedioxythiophene solution (ethanol solution) having a concentration of 35%, taken out after 1 minute, and left for 5 minutes. After immersing in an oxidizing agent / dopant solution consisting of a mixture of 50% aqueous solution of butylamine phenolsulfonate (pH 5) and 30% ammonium persulfate aqueous solution, taken out after 30 seconds and left at room temperature for 30 minutes, Oxidation polymerization was carried out by heating at 50 ° C. for 10 minutes. Thereafter, the tantalum sintered body was immersed in pure water and allowed to stand for 30 minutes, then taken out and dried at 70 ° C. for 30 minutes. After repeating this operation 10 times, the tantalum sintered body was immersed in the dispersion liquid of the conductive composition of Example 1, taken out after 30 seconds, and dried at 70 ° C. for 30 minutes. This operation was repeated twice, and then allowed to stand at 150 ° C. for 30 minutes, and then the conductive composition layer was covered with a carbon paste and a silver paste to produce a tantalum solid electrolytic capacitor.

Example 10
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 2 was used instead of the conductive composition dispersion of Example 1.

Example 11
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 3 was used instead of the conductive composition dispersion of Example 1.

Example 12
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 4 was used instead of the conductive composition dispersion of Example 1.

Example 13
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 5 was used instead of the conductive composition dispersion of Example 1.

Example 14
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 6 was used instead of the conductive composition dispersion of Example 1.

Example 15
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 7 was used instead of the conductive composition dispersion of Example 1.

Example 16
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 9, except that the conductive composition dispersion of Example 8 was used instead of the conductive composition dispersion of Example 1.

Comparative Example 8
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 1 except that the conductive composition dispersion of Comparative Example 1 was used instead of the conductive composition dispersion of Example 1.

Comparative Example 9
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 1, except that the conductive composition dispersion of Comparative Example 3 was used instead of the conductive composition dispersion of Example 1.

Comparative Example 10
A tantalum solid electrolytic capacitor was prepared in the same manner as in Example 1 except that the conductive composition dispersion of Comparative Example 4 was used instead of the conductive composition dispersion of Example 1.

Comparative Example 11
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 1 except that the conductive composition dispersion of Comparative Example 5 was used instead of the conductive composition dispersion of Example 1.

Comparative Example 12
A tantalum solid electrolytic capacitor was produced in the same manner as in Example 1 except that the conductive composition dispersion of Comparative Example 6 was used instead of the conductive composition dispersion of Example 1.

  For the tantalum solid electrolytic capacitors of Examples 9 to 16 and Comparative Examples 8 to 12, ESR and capacitance were measured. The results are shown in Table 3. In addition, the measuring method of ESR and an electrostatic capacitance is as follows.

ESR:
ESR was measured at 25 ° C. and 100 kHz using an LCR meter (4284A) manufactured by Hewlett-Packard.
Capacitance:
The electrostatic capacity was measured at 25 ° C. and 120 Hz using an LCR meter (4284A) manufactured by Hewlett-Packard.
In addition, the measurement is performed for 20 samples for each sample, and the numerical values shown in Table 3 regarding ESR and capacitance are obtained by calculating an average value of the 20 values and rounding off after the decimal point.

  As shown in Table 3, the tantalum solid electrolytic capacitors of Examples 9 to 16 have smaller ESR and larger capacitance than the tantalum solid electrolytic capacitors of Comparative Examples 8 to 12, and are used as tantalum solid electrolytic capacitors. It was excellent.

  Next, 20 tantalum solid electrolytic capacitors randomly selected from the tantalum solid electrolytic capacitors of Examples 9 to 16 and Comparative Examples 8 to 12 were stored at 125 ° C. for 200 hours, and the same as described above. ESR and capacitance were measured. The results are shown in Table 4. In addition, the numerical value shown in Table 4 calculates | requires 20 average values, respectively, and rounds off the decimal part.

  As shown in Table 4, the tantalum solid electrolytic capacitors of Examples 9 to 16 have little increase in ESR and little decrease in capacitance even when stored at 125 ° C. for 200 hours at a long time. The heat resistance was excellent.

[Evaluation as antistatic film]
In Examples 17 to 23 below, evaluation as an antistatic film (antistatic film) is shown.

Example 17
To 100 g of the dispersion liquid of the conductive composition of Example 1, 0.5 g of polyvinyl alcohol and 12 g of water-soluble polyethylene resin [Plus Coat Z-561 (trade name) manufactured by Kyoyo Chemical Industry Co., Ltd.] were added, and then 300 g of pure water. Was completely dissolved by stirring with a stirrer. Thereafter, dispersion treatment was performed for 2 minutes with a T-300 type ultrasonic device manufactured by Nippon Seiki Co., Ltd. Filter through 131 filter paper. 50 μl of the filtrate was dropped on a 2.8 cm × 4.8 cm polyethylene sheet. After uniformizing with a bar coater of No. 2, it was dried at 50 ° C. for 10 minutes and further dried at 120 ° C. for 1 minute to form an antistatic film using the conductive composition as a conductor.

Example 18
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 2 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Example 19
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 3 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Example 20
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 4 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Example 21
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 5 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Example 22
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 6 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Example 23
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Example 7 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Comparative Example 13
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Comparative Example 1 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Comparative Example 14
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Comparative Example 3 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Comparative Example 15
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Comparative Example 4 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Comparative Example 16
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Comparative Example 5 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

Comparative Example 17
The conductive composition was used as a conductor in the same manner as in Example 17, except that the conductive composition dispersion of Comparative Example 6 was used instead of the conductive composition dispersion of Example 1. An antistatic film was formed.

  Conductivity measuring instrument of 4-probe system in accordance with JIS K 7194 for the surface resistance of the antistatic films of Examples 17 to 23 and Comparative Examples 13 to 17 formed as described above at room temperature (about 25 ° C.) It was measured by [MCP-T600 (trade name) manufactured by Mitsubishi Chemical Corporation]. Further, the visible light transmittance (average value of 400 nm to 700 nm) of the antistatic film was measured using UV3100 manufactured by Shimadzu Corporation. The results are shown in Table 5. In addition, measurement is performed for each sample for five points, and the numerical values shown in Table 5 are obtained by calculating an average value of the five points and rounding off after the decimal point.

  As shown in Table 5, the antistatic films of Examples 17 to 23 have lower surface resistance and the same or higher visible light transmittance than the antistatic films of Comparative Examples 13 to 17. It was excellent as an antistatic film. This is considered to be due to the fact that the conductive compositions used as the conductors in the antistatic films of Examples 17 to 23 have high conductivity and high transparency.

Claims (9)

An organic sulfonate composed of a polystyrene sulfonate having a number average molecular weight of 10,000 to 300,000 and an aromatic sulfonate, wherein the aromatic sulfonate is part of the polystyrene sulfonate portion of the polystyrene sulfonate. A conductive polymer synthesized by oxidative polymerization of pyrrole or a derivative thereof using an organic sulfonate having an aromatic sulfonic acid moiety of 20 to 50% by mass and a persulfate , A conductive composition having a pH of 1.5 to 4.5 when the total amount of the polymer and the one derived from the added pH improver is 1% by mass.   2. The conductivity according to claim 1, wherein the aromatic sulfonate is at least one selected from the group consisting of naphthalene sulfonate, naphthalene disulfonate, naphthalene trisulfonate, tetralin sulfonate, and phenol sulfonate. Composition. An organic sulfonate comprising a polystyrene sulfonate having a number average molecular weight of 10,000 to 300,000 and an aromatic sulfonate, wherein the aromatic sulfonate is aromatic relative to the polystyrene sulfonate portion of the polystyrene sulfonate. Conductive polymer obtained by oxidative polymerization of pyrrole or a derivative thereof at 0 to 50 ° C. in the presence of water using an organic sulfonate having a sulfonic acid portion of 20 to 50% by mass and a persulfate. The concentration of the total amount of the conductive polymer and the one derived from the added pH improver is 1% by mass through the step of synthesizing and neutralizing with an organic cation. A method for producing a conductive composition, comprising producing a conductive composition having a pH of 1.5 to 4.5 when a dispersion is formed.   A dispersion of a conductive composition, wherein the conductive polymer according to claim 1 or 2 is dispersed in water at a concentration of 1 to 40% by mass.   The dispersion liquid of the electrically conductive composition of Claim 4 containing alcohol.   The dispersion liquid of the electroconductive composition of Claim 4 or 5 containing binder resin.   An antistatic film comprising the conductive composition according to claim 1 or 2 as a conductor. An antistatic sheet comprising the antistatic film according to claim 7 formed on at least one surface of a sheet substrate.   A solid electrolytic capacitor comprising the conductive composition according to claim 1 or 2 as a solid electrolyte.