JP2009147122A - Solid-state electrolytic capacitor, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state electrolytic capacitor which has high electrostatic capacity and good controllability of a manufacturing process and further includes a conductive high polymer layer, and to provide a manufacturing method thereof. <P>SOLUTION: A porous anode body 1 has an anodic oxidation coating 2 on a surface and is made of a valve action metal body. The solid-state electrolytic capacitor is manufactured using a process wherein after the anodic oxidation coating 2 is coated with a water dispersant containing polyethylene dioxythiophene and polystyrenesulfonic acid by using a discharging machine, the water dispersant is heated to be dried and cured to provide the conductive high polymer layer 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor using a conductive polymer layer as a solid electrolyte and a method for manufacturing the same.

  In recent years, an anodized film is formed on the surface of an anode body made of a porous body of a valve action metal body such as aluminum, niobium, tantalum, titanium, and magnesium by an anodizing method. A solid electrolytic capacitor in which a molecular layer is further formed and this conductive polymer layer is used as a solid electrolyte has been developed. In such a capacitor, the conductivity of the solid electrolyte is 10 to 100 times higher than that of a conventional solid electrolytic capacitor using manganese dioxide as a solid electrolyte, and ESR (equivalent series resistance) can be greatly reduced. Therefore, it is expected to be applied to various uses such as for absorbing high-frequency noise in small electronic devices.

  In general, in order to form a conductive polymer layer used as a solid electrolyte of a solid electrolytic capacitor on an anodic oxide film, 3,4-ethylenedioxythiophene (hereinafter referred to as EDOT), pyrrole, aniline, etc. A chemical oxidative polymerization method is used in which an oxidizing agent and a dopant (conducting aid) are added to a monomer, and the monomer and the oxidizing agent are directly reacted on a dielectric oxide film to form a conductive polymer layer. There is also known an electropolymerization method in which an electrolyte solution serving as a monomer and a dopant is applied on a conductive underlayer, and a conductive polymer layer is formed by applying a voltage between the underlayer and the electrolyte solution. .

  In Patent Document 1, EDOT and iron (III) p-toluenesulfonate, which also serves as an oxidant and a dopant, are dissolved in an organic solvent and applied to the surface of an aluminum electrode that has been subjected to surface oxidation. A method for forming a conductive polymer layer by a chemical oxidative polymerization method is described in which an organic solvent is removed after formation and a conductive polymer layer is formed. Patent Document 2 describes a method in which a polypyrrole or polyaniline conductive polymer layer formed by a chemical oxidative polymerization method is used as a base, and a homogeneous conductive polymer layer is further formed on the surface thereof by an electrolytic polymerization method. ing.

  On the other hand, without conducting chemical oxidative polymerization on the surface of the anodic oxide film that is a porous body, a solution containing a conductive polymer that has been polymerized in advance is prepared, and the surface of the anode body is impregnated with the solution. A slurry polymer coating method is also known in which a conductive polymer layer is formed by drying and forming a coating film. In the slurry polymer coating method, the polymerization reaction does not proceed on the surface of the dielectric oxide film as in the above-mentioned chemical oxidative polymerization method and electrolytic polymerization method, but the monomer, the oxidant, and the dopant are added to the container and stirred. This causes a polymerization reaction by chemical oxidation. Since this method does not require the polymerization reaction to be performed on the anodized film, it has a feature that the production process is relatively easy to control.

  Patent Document 3 describes a method of forming a conductive film by this slurry polymer coating method, which is used as an electrode of batteries capable of reversible charging. According to Patent Document 3, EDOT and iron (III) p-toluenesulfonate, which is an oxidizing agent, are dissolved in an organic solvent, applied to the surface of a polycarbonate resin, and dried, so that the surface resistance is low. Highly conductive polymer layer can be formed.

  Patent Document 4 describes a composition using a conductive polymer water-soluble compound composed of EDOT and a polyanion prepared by a slurry polymer coating method. In this water-soluble compound, a self-emulsifying polyester aqueous dispersion composed of an aromatic dicarboxylic acid and a diol is mixed with a conductive polymer to improve adhesion, conductivity, water resistance, and the like. Furthermore, Patent Document 5 describes a coating film made of a conductive polymer, which is similarly produced from EDOT and polyanion by a slurry polymer coating method and becomes a stable dispersion with respect to an aqueous solution. The conductive polymer compounds proposed in Patent Document 4 and Patent Document 5 are assumed to be used as an antistatic coating agent used by coating on the surface of an article or a coating film thereof.

  Here, details of the case where a slurry polymer coating method is applied to a solid electrolytic capacitor to produce a solid electrolytic capacitor having a conductive polymer layer as a solid electrolyte layer by the same method will be considered. Specifically, a porous anode body having an anodized film formed on the surface of a conductive polymer solution (aqueous solution, organic solution) produced by treating EDOT with an oxidizing agent that also serves as a dopant such as a polyanion. It is assumed that a conductive polymer layer is formed by applying to the substrate. In this case, it is generally known that there is a reciprocal relationship between the permeability of the conductive polymer solution into the anodized film and the molecular weight. On the other hand, the conductivity of the coating film formed by coating tends to be proportional to its molecular weight. From this, when a solid electrolyte layer of a solid electrolytic capacitor is formed by applying a conductive polymer solution, a polymer solution having a large molecular weight may be used in order to increase the conductivity and decrease the ESR. become. However, in that case, due to the low permeability of the conductive polymer solution, the solid electrolyte layer is hardly formed inside the fine irregularities of the anodized film, and only the surface layer is formed. The capacitance of the solid electrolytic capacitor is lowered.

  Therefore, a method of forming the solid electrolyte layer in two stages has been considered. This method uses a chemical oxidative polymerization method in which an oxidizing agent and a dopant (conducting aid) are first added to a monomer, and the monomer and the oxidizing agent are directly reacted on the anodized film to form a conductive polymer layer. ing. Next, a highly conductive conductive polymer layer is formed using a conductive polymer solution having a high molecular weight and high conductivity.

Japanese Patent No. 3040113 Japanese Patent Publication No. 3-61331 Japanese Patent Laid-Open No. 1-313521 JP 2002-60736 A Japanese Patent Laid-Open No. 7-90060

  As described above, in order to form a solid electrolyte layer of a solid electrolytic capacitor by the conventional technique, a process of chemical oxidative polymerization as in Patent Document 1 or Patent Document 2 is required. Even when the slurry polymer coating method is used, it is necessary to perform at least two steps of forming a solid electrolyte layer in order to ensure capacitance and increase the conductivity of the conductive polymer layer. Since the formation of the first solid electrolyte layer by means of the step requires the immersion impregnation step of the monomer, the oxidizing agent, and the dopant (conducting auxiliary agent) to the valve action metal body a plurality of times, the manufacturing process becomes complicated and the product management is difficult. Problems arise.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a solid electrolytic capacitor having a conductive polymer layer having a high electrostatic capacity and high conductivity and manufactured by a manufacturing process with good controllability, and a manufacturing method thereof.

  As a means for solving the above problems, a method using a slurry polymer was developed, and (1) a water dispersion of a polyethylene oxythiophene represented by Chemical Formula 1 and a polystyrene sulfonic acid represented by Chemical Formula 2 having a valve action metal body having an oxide film layer. A method of washing the surface of the valve action metal body with water after being immersed in the body, and (2) after applying the water dispersion to the valve action metal body with a discharger, the surface of the valve action metal body with water A method of cleaning is conceivable.

  By the way, as a product of a water-soluble compound of a conductive polymer used for forming a solid electrolyte layer by a method using a slurry polymer, trade name Baytron-P (manufactured by Starck, Germany) is preferable. This is because EDOT as a monomer and polystyrene sulfonic acid (hereinafter referred to as PSSA) as an oxidant and a dopant are added to an aqueous solution, respectively, and mixed with stirring to polyethylenedioxythiophene (hereinafter referred to as PEDOT) which is a conductive polymer. Is an aqueous dispersion of a high molecular weight polymer. Baytron-P contains 0.5 parts by weight of PEDOT and 0.8 parts by weight of PSSA in 100 parts by weight, and contains a small amount of other additives, but most of the remainder is water. The average molecular weight of PSSA contained is about 150,000 as measured by high performance liquid chromatography mass spectrometry.

  However, Baytron-P has a large molecular volume because it is composed of a polymer, and when applied to the surface of the valve metal body as it is and dried by heating, the valve action metal body having pores of several hundred nm or less inside. Since it does not penetrate into the interior and a solid electrolyte cannot be formed on the anodized film, a capacitance of only a few μF appears. That is, the basic problem in applying the method using the slurry polymer to the formation of the conductive polymer layer of the solid electrolytic capacitor remains as it is.

  In such a situation, the present inventors sprayed the water dispersion on the surface of the valve metal body using a dispenser and applied the water dispersion adhered to the surface of the valve metal body with water. It was found that the electrostatic capacity increased to 240 μF or more (the electrostatic capacity in the electrolytic solution was 300 μF) by repeating washing and heating and drying.

  As a result of the study by the present inventors, in the application of the aqueous dispersion to the valve action metal body using a discharger, the application pattern is a non-contact, intermittent or continuous application of the aqueous dispersion in a non-contact manner. By applying the method (spray method) or the method (dot method) of applying the water dispersion on the valve action metal body surface by adjusting the nozzle diameter and hydraulic pressure of the discharger accessory, It has been confirmed that the improvement is significant. When the spray method and the dot method were used, the aqueous dispersion could be uniformly applied to the surface of the valve action metal body, and a uniform film could be formed after heat drying. On the other hand, in the application of the aqueous dispersion to the valve action metal body using a discharger, the aqueous dispersion is applied in a linear manner (bead method) and the aqueous dispersion is ejected by intermittent or continuous coating. When the non-contact coating method (spiral spray method) is used (spiral spray method) mainly in air), it is difficult to uniformly apply the water dispersion onto the surface of the valve action metal body. Film formation was difficult, and no significant improvement in appearance capacity was observed.

  As a result of the study by the present inventors, the number of times of application in the application of the aqueous dispersion to the valve action metal body using a discharger and the appearance capacity of the valve action metal body after each application are washed with water. It has been confirmed that the improvement is significant. In addition, when the water dispersion was applied by a discharger and was not washed with water and directly dried by heating, the appearance capacity was not improved. On the other hand, when the water dispersion was applied to the valve action metal body surface without using a discharger from experiments conducted by the present inventors, the discharger was used regardless of the number of times of application and washing with water after application. It did not reach the appearance capacity when used.

  In summary, in the solid electrolytic capacitor of the present invention, an aqueous dispersion of polyethylene dioxythiophene and polystyrene sulfonic acid is applied to a porous valve metal body having an anodized film formed on the surface using a discharger. A solid electrolyte having a conductive polymer layer formed by drying is provided.

  In the method for producing a solid electrolytic capacitor of the present invention, an aqueous dispersion of polyethylene dioxythiophene and polystyrene sulfonic acid is applied to a porous valve metal body having an anodized film formed on the surface, and dried. It has the manufacturing process of the solid electrolyte which forms a conductive polymer layer by this.

  The polystyrene sulfonic acid contained in the aqueous dispersion may have an average molecular weight of 10,000 to 150,000 measured by high performance liquid chromatography mass spectrometry.

  The polyethylenedioxythiophene contained in the aqueous dispersion may have a molecular weight of 5,000 to 10,000 as measured by mass spectrometry.

  As an application mode of a discharger used for the application method of the aqueous dispersion, a method of spraying the aqueous dispersion in a non-contact, intermittent or continuous application in a mist form (spray method), or a nozzle diameter of a discharger-attached nozzle and It is preferable to use a method (dot method) in which the water dispersion is applied to the surface of the valve action metal body in a dot shape by adjusting the hydraulic pressure.

  The water dispersion may be applied by applying the water dispersion 5 to 50 times to the valve metal body by a discharger to form a solid electrolyte layer.

  When the aqueous dispersion is applied to the valve action metal body by a dispenser, the solid electrolyte is obtained by washing the surface of the valve action metal body with water after each application of 5 to 50 times. A layer may be formed.

  A solid electrolyte layer made of a conductive polymer may be formed on the surface of the porous valve metal body on which the anodized film is formed by solidifying the aqueous dispersion applied by the discharger by heating and drying.

  The heating temperature at the time of drying and solidifying the aqueous dispersion is preferably 105 ° C. or higher.

  The application pressure when applying the aqueous dispersion with a dispenser is preferably 10 kPa or less.

  The porous valve metal body may be a metal body selected from aluminum, tantalum, and niobium.

  According to the present invention, while using a process for forming a conductive polymer layer suitable for manufacturing, the coverage of the anode body surface oxide film layer is increased to ensure capacitance, and the conductivity of the conductive polymer layer is increased. An improved solid capacitor and its manufacturing method is obtained.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a solid electrolytic capacitor according to the present invention, FIG. 1 (a) is a schematic cross-sectional view thereof, and FIG. 1 (b) is an enlarged cross-sectional view showing a portion A of FIG. 1 (a). 1 is an anode body, 2 is an anodized film, 3 is an insulating resist part, 4 is a conductive polymer layer, 5 is a graphite layer, 6 is a metal layer made of adhesive silver, 7 is a cathode part, and 8 is an anode part. Indicates. The solid electrolytic capacitor in FIG. 1 is a type called a three-terminal type.

  In the embodiment of the present invention, other than the step of forming the conductive polymer layer, a known technique is used. That is, after the surface layer vicinity of the aluminum foil is made porous by etching, a dielectric oxide film layer is formed by anodic oxidation, and after forming a solid electrolyte layer including the conductive polymer layer according to the present embodiment, A cathode part is prepared, external terminals are connected to the anode part and the cathode part, and an exterior is provided to obtain the solid electrolytic capacitor of the present embodiment.

  In the manufacturing process of the solid electrolyte layer in the present embodiment, an aqueous dispersion of polyethylene dioxythiophene and polystyrene sulfonic acid is applied to a porous valve metal body having an anodized film formed on the surface using a discharger. A conductive polymer layer is formed by drying.

  The polystyrene sulfonic acid contained in the aqueous dispersion should have an average molecular weight of 10,000 to 150,000 measured by high performance liquid chromatography mass spectrometry. At this time, when the average molecular weight is less than 10,000 or more than 150,000, it is not preferable in that a uniform aqueous dispersion cannot be formed and the conductivity of the conductive polymer layer cannot be increased.

  The polyethylenedioxythiophene contained in the aqueous dispersion has a molecular weight of 5,000 to 10,000 as measured by mass spectrometry. At this time, when the molecular weight is less than 5,000, the conductivity and reliability of the conductive polymer layer are not sufficient, and when it exceeds 10,000, the dispersibility in the aqueous dispersion is lowered and the coverage is lowered. This is not preferable in that the capacitance is lowered. Moreover, it can also be said that the range of molecular weight 5,000-10,000 is a range suitable for apply | coating an aqueous dispersion using a discharger.

  By the way, as a coating form of the discharger used in the coating method of the aqueous dispersion, a method of spraying the aqueous dispersion in a non-contact, intermittent or continuous coating in a mist form (spray method) or a nozzle diameter and liquid of the discharger A method (dot method) is used in which the water dispersion is applied in the form of dots on the surface of the valve metal body by adjusting the pressure.

  In the application method of the aqueous dispersion, the solid electrolyte layer is formed by applying the aqueous dispersion 5 to 50 times to the valve action metal body by a discharger.

  Further, when the water dispersion is applied to the valve action metal body by a dispenser, the surface of the valve action metal body is washed with water after each application of 5 to 50 times to form a solid electrolyte. Form a layer.

  A solid electrolyte layer made of a conductive polymer may be formed on the surface of the porous valve action metal body on which an anodized film is formed by solidifying the aqueous dispersion applied by the discharger by heating and drying. The heating temperature for drying and solidifying the body is 105 ° C or higher.

  Moreover, the application pressure (discharge pressure) at the time of apply | coating an aqueous dispersion with a discharge machine shall be 10 kPa or less.

  In addition to aluminum, tantalum and niobium can be used for the porous valve metal body.

    Hereinafter, examples of the present invention will be described together with other prototypes.

  A description will be given of the result of making a prototype by changing the production conditions of the conductive polymer layer, measuring the characteristics, and determining the final feasibility (coverage, film quality by appearance). The structure of the solid electrolytic capacitor at that time is the same as that shown in FIG. 1, and the anode body 1 is subjected to surface enlargement and anodization on an aluminum foil of about 10 × 10 × 0.15 mm, with a withstand voltage of 3V. The one whose electrostatic capacity (120 Hz) in the liquid is 300 μF was used.

  Table 1 shows the measurement results of the appearance capacity of the solid electrolytic capacitors by the conductive polymer layer forming method of Measurement Examples 1 to 25 and the coverage calculated by dividing the appearance capacity by the electrostatic capacitance in the liquid. Yes. The capacitance (capacitance) was measured at 120 Hz, and the number of measurement samples was 20 for each of measurement examples 1 to 21. The numerical values shown in Table 1 are average values of the measurement results of 20 samples each. In measurement examples 1 to 24, the drying temperature of the sample is fixed at 105 ° C. In addition, the final availability of each measurement example is determined and written as “O” (pass) and “X” (defect). Further, in Measurement Examples 6 to 25, the discharge pressure (application pressure) at the time of applying the aqueous dispersion to the valve metal surface by the discharger was fixed to 1 kPa. In Table 1, with respect to measurement examples (examples according to the present invention) within the scope of the claims, ◎ is marked in the column of “Invention”.

  According to the results in Table 1, when the spray method and the dot method were used as the dipping method and the discharge mode of the discharger, no case in which a defective sample was generated in the appearance when dried and solidified occurred regardless of the number of times of application. . However, when the bead method and spiral spray method were used as the discharge mode of the discharger, appearance defects occurred during drying and solidification regardless of the number of times of application. In the case of an aluminum solid electrolytic capacitor having a withstand voltage of 3 V and an electrostatic capacity of 300 μF and having a conductive polymer layer, the minimum capacity assumed at a measurement frequency of 120 Hz is 200 μF. Cannot be used for various purposes. Measurement example 1 (when the valve action metal body is immersed once in the water dispersion and then dried and solidified) and measurement examples 2 to 5 (the valve action metal body is immersed in the water dispersion a plurality of times, In the case of drying and solidifying after washing with water, the appearance capacity was as low as 5 μF regardless of the number of immersions.

  Further, in Measurement Example 6 (when the aqueous dispersion was applied once to the valve action metal body by a spray method and then dried and solidified), the appearance capacity was as low as 80 μF. However, in Measurement Examples 7 to 10 (when the water dispersion is applied to the valve action metal body a plurality of times by spraying, washed with water a plurality of times, and then dried and solidified), the appearance capacity is 240 μF, which is good Met.

  In addition, in measurement example 11 (when the water dispersion was applied once to the valve action metal body by the dot method and then dried and solidified), the appearance capacity was as low as 80 μF. However, in measurement examples 12 to 15 (when the water dispersion was applied to the valve action metal body a plurality of times by the dot method, washed with water a plurality of times and then dried and solidified), the appearance capacity was 240 μF, which was good Met.

  In Measurement Example 16 (when the aqueous dispersion was applied once to the valve action metal body by the bead method and dried and solidified), the appearance capacity was as low as 80 μF. In 20 (when the aqueous dispersion was applied to the valve action metal body a plurality of times by the bead method, washed with water a plurality of times, and then dried and solidified), the appearance capacity was as low as 120 μF.

  In addition, in measurement example 21 (when the water dispersion was applied once to the valve action metal body by the spiral spray method and then dried and solidified), the appearance capacity was as low as 80 μF, and measurement example 12 To 15 (when the water dispersion was applied to the valve action metal body a plurality of times by the bead method, and after being washed with water a plurality of times and then dried and solidified), the appearance capacity was as low as 120 μF.

  As described above, in order to produce an aluminum solid electrolytic capacitor having a sufficient capacity in use, when the water dispersion is applied to the valve action metal body using a discharger, the spray method and the dot method are preferable as the application method. The number of times of application and washing is preferably at least 5 times. In addition, after apply | coating the said water dispersion to a valve action metal body with a discharge machine, the liquid phase part which consists of a water dispersion is dried and solidified by heating, but the range of a drying temperature is measured from the measurement example 26 of the postscript. Considered separately in Example 31.

  Table 2 shows the measurement results of the appearance capacity of the solid electrolytic capacitors by the conductive polymer layer forming method of Measurement Examples 26 to 40, and the coverage calculated by dividing the appearance capacity by the electrostatic capacitance in the liquid. Yes. The capacity is measured at 120 Hz, and the number of measurement samples is 20 for each of the measurement examples 26 to 40. The numerical values shown in Table 2 are average values of the measurement results of 20 samples each. In the measurement examples 26 to 28, after the immersion of the valve action metal body in the water dispersion in the immersion method, the number of series of steps of washing with water is fixed to 5 times. In Measurement Examples 29 to 40, the number of the series of steps of washing with water after application of the water dispersion to the surface of the valve metal body by the dispenser was fixed to 5 times. Moreover, the discharge pressure at the time of apply | coating to the valve action metal body surface of the said water dispersion by a discharge machine in the measurement examples 29-40 was fixed to 1 kPa. In addition, the final availability of each measurement example is determined and written as “O” (pass) and “X” (defect). In Table 2, ◎ is marked in the “Invention” column for measurement examples (examples according to the present invention) within the scope of the claims.

  According to the results in Table 2, when the spray method and the dot method are used as the dipping method and the discharge mode of the discharger, the drying temperature is 105 ° C or more in the case where a defective sample appears in the appearance when dried and solidified. Did not occur. However, when the bead method and the spiral spray method were used as the discharge mode of the discharger, poor appearance occurred during drying and solidification regardless of the drying temperature. In the case of an aluminum solid electrolytic capacitor having a withstand voltage of 3 V and an electrostatic capacity of 300 μF and having a conductive polymer layer, the minimum capacity assumed at a measurement frequency of 120 Hz is 200 μF. Cannot be used for various purposes. In measurement example 26 (when the valve action metal body is immersed in the aqueous dispersion and then subjected to a series of steps of washing with water five times and then dried and solidified at 85 ° C.), The resulting liquid phase portion did not sufficiently dry and solidify, resulting in poor appearance. Measurement Example 27 and Measurement Example 28 (when the valve action metal body is immersed in the aqueous dispersion and then washed with water five times, then dried and solidified at 105 ° C. and 150 ° C.) ), The appearance capacity was as low as 5 μF regardless of the sample drying temperature.

  In measurement example 29 (when the water dispersion is applied to the valve action metal body by a spray method and then washed with water for 5 times and then heated to 85 ° C. and dried), the water is used. The liquid phase portion made of the dispersion did not sufficiently dry and solidify, resulting in poor appearance. However, measurement examples 30 and 31 (the water dispersion was applied to the valve action metal body by a spray method, and then a series of steps of washing with water was performed 5 times, and then heated to 105 ° C. or 150 ° C. and dried. In the case), the liquid phase portion composed of the aqueous dispersion was sufficiently dried and solidified, no appearance defect occurred, and the appearance capacity was 240 μF, which was good.

  In measurement example 32 (when the water dispersion is applied to the valve action metal body by the dot method and then washed with water five times and then heated to 85 ° C. and dried), the water is used. The liquid phase portion made of the dispersion did not sufficiently dry and solidify, resulting in poor appearance. However, in measurement examples 33 and 34 (the water dispersion was applied to the valve action metal body by the dot method, and then a series of steps of washing with water was performed 5 times, and then heated to 105 ° C. or 150 ° C. and dried. In the case), the liquid phase portion composed of the aqueous dispersion was sufficiently dried and solidified, no appearance defect occurred, and the appearance capacity was 240 μF, which was good.

  In Measurement Example 35 (when the water dispersion is applied to the valve action metal body by the bead method and then washed with water five times and then heated to 85 ° C. and dried), the water is used. The liquid phase portion made of the dispersion did not sufficiently dry and solidify, resulting in poor appearance. Measurement Examples 36 and 37 (when the aqueous dispersion was applied to the valve action metal body by the bead method, and then a series of steps of washing with water was performed 5 times, followed by heating to 105 ° C. or 150 ° C. and drying. ), The liquid phase portion composed of the aqueous dispersion sufficiently dried and solidified, but the appearance capacity was as low as 120 μF.

  In Measurement Example 38 (when the water dispersion is applied to the valve action metal body by the spiral spray method, and then a series of steps of washing with water is performed 5 times and then heated to 85 ° C. and dried), Drying and solidification of the liquid phase portion made of the aqueous dispersion did not proceed sufficiently, resulting in poor appearance. Measurement Examples 39 and 40 (After applying the aqueous dispersion to the valve action metal body by a spiral spray method, a series of steps of washing with water was performed 5 times, and then heated to 105 ° C. or 150 ° C. and dried. In the case), the liquid phase portion made of the aqueous dispersion sufficiently dried and solidified, but the appearance capacity was as low as 120 μF.

  As described above, in order to produce an aluminum solid electrolytic capacitor having a sufficient capacity in use, when the water dispersion is applied to the valve action metal body using a discharger, the spray method and the dot method are preferable as the application method. The number of times of application and washing is preferably at least 5 times. In the drying and solidification after a series of steps of washing with water after applying the aqueous dispersion, heating to 105 ° C. or more is preferred. Note that the discharge pressure of the water dispersion when the water dispersion is applied to the valve action metal body with a discharger is separately examined in measurement examples 41 to 56 described later.

  Table 3 shows the results of measurement of the appearance capacity of the solid electrolytic capacitors by the conductive polymer layer forming method of Measurement Example 41 to Measurement Example 56 and the coverage calculated by dividing the appearance capacity by the electrostatic capacitance in the liquid to be a percentage. Each is shown. The capacities were measured at 120 Hz, and the number of measurement samples was 20 for each of the measurement examples 41 to 56. The numerical values shown in Table 3 are average values of the measurement results of 20 samples each. In Measurement Example 41, the number of series of steps of washing with water after the immersion of the valve action metal body in the immersion method in the water dispersion is fixed to 5 times. In measurement examples 41 to 56, the drying temperature after a series of steps of washing with water after application of the water dispersion to the surface of the valve action metal body by a discharger is fixed at 105 ° C. The final propriety of each measurement example is determined, and is described as ◯ (pass) and x (defect). In Table 3, ◎ is marked in the “Invention” column for measurement examples (examples according to the present invention) within the scope of the claims.

  According to the results in Table 3, when the spray method and the dot method are used as the discharge mode of the discharger, the case where a defective sample is generated in the appearance at the time of drying and solidification occurs when the discharge pressure of the water dispersion by the discharger is 10 kPa. It did not occur if: However, when the bead method and the spiral spray method were used as the discharge mode of the discharger, poor appearance occurred during drying and solidification regardless of the discharge pressure of the water dispersion. In the case of an aluminum solid electrolytic capacitor having a withstand voltage of 3 V and an electrostatic capacity of 300 μF and having a conductive polymer layer, the minimum capacity assumed at a measurement frequency of 120 Hz is 200 μF. Cannot be used for various purposes. Although not described in Table 3, in other measurement examples (when the valve action metal body is immersed in the water dispersion and then washed with water, a series of steps are performed five times), the sample drying temperature Regardless, the appearance capacity was as low as 5 μF.

  In addition, measurement example 41 to measurement example 43 (a series of cleaning with water after setting the discharge pressure output of the water dispersion to 1 to 10 kPa, applying the water dispersion to the valve action metal body by a spray method) When the process was repeated 5 times and heated to 105 ° C. and dried, the appearance capacity was 240 μF, which was good. However, after the measurement example 44 (the discharge pressure of the water dispersion was set to 20 kPa, the water dispersion was applied to the valve action metal body by the spray method, and then a series of steps of washing with water was performed five times. In the case of heating to 105 ° C. and drying), since the discharge pressure of the aqueous dispersion was too strong, the liquid phase portion could not be formed on the uniform valve action metal body, resulting in poor appearance.

  Further, measurement examples 45 to 47 (a series of steps in which the discharge pressure of the water dispersion is set to 1 to 10 kPa, the water dispersion is applied to the valve action metal body by the dot method, and then washed with water is performed. When the sample was heated to 105 ° C. and dried after repeated operations, the appearance capacity was 240 μF, which was good. However, measurement example 48 (after setting the discharge pressure of the water dispersion to 20 kPa, applying the water dispersion to the valve action metal body by the dot method, and then performing a series of steps of washing with water five times. In the case of heating to 105 ° C. and drying), since the discharge pressure of the aqueous dispersion was too strong, the liquid phase portion could not be formed on the uniform valve action metal body, resulting in poor appearance.

  Further, measurement example 49 to measurement example 51 (a series of steps in which the discharge pressure of the water dispersion is set to 1 to 10 kPa, the water dispersion is applied to the valve action metal body by a bead method, and then washed with water. In the case of heating to 105 ° C. and drying after 5 times), the appearance capacity became 120 μF, which was low. However, in Measurement Example 52 (the discharge pressure output of the water dispersion was set to 20 kPa, the water dispersion was applied to the valve metal body by the dot method, and then a series of steps of washing with water was performed five times. In the case of further heating to 105 ° C. and drying), since the discharge pressure of the aqueous dispersion was too strong, a uniform liquid phase portion could not be formed on the valve action metal body, resulting in poor appearance.

  In addition, measurement example 53 to measurement example 55 (a series of water discharge after setting the discharge pressure of the water dispersion to 1 to 10 kPa and applying the water dispersion to the valve action metal body by a spiral spray method) When the process was performed 5 times and then heated to 105 ° C. and dried), the appearance capacity was as low as 120 μF. Measurement Example 56 (The discharge pressure of the water dispersion was set to 20 kPa, and the water dispersion was applied to the valve action metal body by a spiral spray method, and then a series of steps of washing with water was performed five times. In the case of further heating to 105 ° C. and drying), since the discharge pressure of the aqueous dispersion was too strong, a uniform liquid phase portion could not be formed on the valve action metal body, resulting in poor appearance.

  Thus, in order to produce an aluminum solid electrolytic capacitor having a sufficient capacity for use, the conductive polymer layer is formed on the anodized film by applying the water dispersion to the valve action metal body using a discharger. The spray method and the dot method are preferable as the coating method, and the number of times of coating and washing is preferably at least 5 times. After the water dispersion is applied, washing is performed with water. In the drying and solidification, it is preferable to heat to 105 ° C. or higher, and the discharge pressure when discharging the aqueous dispersion is preferably 10 kPa or less.

  In each of the above measurement examples, the case where porous aluminum was used as the valve action metal body for forming the anode body was shown, but it is suitable as the valve action metal body in the electrolytic capacitor and has a good surface. Any metal other than aluminum may be used as long as it can form an anodized film. As such metals, tantalum, niobium and the like are known, and even when these metals are made porous and used as an anode body, the same solid electrolyte as in the case of aluminum can be obtained by the method of the present invention. Capacitors can be formed.

  As described above, according to the solid electrolytic capacitor of the present invention, an aqueous dispersion containing PEDOT and PSSA is applied to a valve action metal body using a discharger, and dried and solidified to form on the anodized film. A conductive polymer layer is formed to produce a solid electrolytic capacitor. By this method, it is possible to provide a solid electrolytic capacitor having a sufficient appearance capacity in general use without requiring complicated manufacturing steps. Further, the description of the above example is mainly for explaining the effect mainly in the case of the embodiment of the present invention, thereby limiting the invention described in the scope of claims or the scope of claims. It does not reduce. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

FIG. 1A is a schematic cross-sectional view of a solid electrolytic capacitor according to the present invention, and FIG. 1B is an enlarged cross-sectional view of a portion A in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anode body 2 Anodized film 3 Resist part 4 Conductive polymer layer 5 Graphite layer 6 Metal layer 7 Cathode part 8 Anode part

Claims (11)

  A conductive polymer layer solid formed by applying an aqueous dispersion of polyethylenedioxythiophene and polystyrenesulfonic acid to a porous valve metal body with an anodized film formed on the surface and drying using a dispenser. A solid electrolytic capacitor comprising an electrolyte.   A solid electrolyte that forms a conductive polymer layer by applying an aqueous dispersion of polyethylenedioxythiophene and polystyrenesulfonic acid to a porous valve-acting metal body with an anodized film on the surface and drying using a dispenser The manufacturing method of the solid electrolytic capacitor characterized by having the manufacturing process of these.   3. The solid electrolytic capacitor according to claim 2, wherein the polystyrene sulfonic acid contained in the aqueous dispersion has an average molecular weight of 10,000 to 150,000 measured by high performance liquid chromatography mass spectrometry. Method.   4. The solid electrolytic capacitor according to claim 2, wherein the polyethylenedioxythiophene contained in the aqueous dispersion has a molecular weight of 5,000 to 10,000 as measured by mass spectrometry. 5. Method.   As a coating form of a discharger used for the coating method of the water dispersion, a method of spraying the water dispersion in a non-contact, intermittent or continuous coating in a mist form (spray method) or a nozzle diameter and liquid of the discharger The solid electrolysis according to any one of claims 2 to 4, wherein a method (dot method) is used in which the water dispersion is applied in a dot-like manner on the surface of the valve metal body by adjusting the pressure. Capacitor manufacturing method.   6. The method according to claim 2, wherein the aqueous dispersion is applied by applying the aqueous dispersion 5 to 50 times to the valve action metal body by a discharger. Any one item | item is a manufacturing method of a solid electrolytic capacitor.   When the aqueous dispersion is applied to the valve action metal body by a dispenser, the solid electrolyte is obtained by washing the surface of the valve action metal body with water after each application of 5 to 50 times. The method for producing a solid electrolytic capacitor according to claim 6, wherein a layer is formed.   A solid electrolyte layer made of a conductive polymer is formed on the surface of the porous valve metal body on which the anodized film is formed by solidifying the aqueous dispersion applied by the discharger by heating and drying. The manufacturing method of the solid electrolytic capacitor of any one of Claims 2-7.   The method for producing a solid electrolytic capacitor according to claim 8, wherein a heating temperature in drying and solidifying the aqueous dispersion is 105 ° C. or higher.   The method for producing a solid electrolytic capacitor according to any one of claims 2 to 9, wherein a coating pressure when the water dispersion is applied by a discharger is 10 kPa or less.   The method for manufacturing a solid electrolytic capacitor according to any one of claims 2 to 10, wherein the porous valve metal body is a metal body selected from aluminum, tantalum, and niobium.

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