JPH10298427A - Composition for forming electrolyte of solid electrolyte capacitor and solid electrolyte capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrolyte having excellent thermal shock resistance by selecting an electrolyte which comprises a solution containing at least aniline and a solution containing at least an oxidizing agent and in which at lest either of the solutions contains an organic solution freely miscible with water. SOLUTION: This composition comprises an aqueous solution containing aniline and an aqueous solution containing an oxidizing agent. Solution A comprising 27-90 wt.% water and 9.5-70 wt.% organic solvent (e.g. alkyl alcohol) freely miscible with water is prepared and then deaerated. Solution B comprising 0.2-23 wt.% organic sulfonic acid type oxidizing agent (e.g. benzenesulfonic acid), 0.2-23 wt.% ammonium peroxydisulfate, 30-95 wt.% water and 4-69 wt.% organic solvent is prepared. The electrolyte layer of a solid electrolyte capacitor is formed by infiltrating solution B into an element prepared by forming an oxide film on a valve metal, then infiltrating solution A thereinto, polymerizing the aniline into a polyaniline, drying the assemblage, repeating the step including the above operations once to several tens times and dehydrating the final assemblage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution for forming an electrolyte of a solid electrolytic capacitor and a solid electrolytic capacitor, and more particularly to a solution for forming an electrolyte of a solid electrolytic capacitor in which an electrolyte is formed by chemical oxidative polymerization of aniline. The present invention relates to a solid electrolytic capacitor formed with an electrolyte.

[0002]

2. Description of the Related Art A conventional solid electrolytic capacitor uses a tantalum pellet called a valve metal or a molded product obtained by expanding an aluminum surface as an anode body, forms an oxide film on the surface thereof to form a dielectric, and forms manganese dioxide or manganese dioxide. , 7 ', 8, 8'-tetracyanoquinodimethane complex salt (TCNQ) or the like as an electrolyte layer. However, since manganese dioxide has an insufficient conductivity of 0.1 S / cm, a solid electrolytic capacitor using the manganese dioxide as an electrolyte layer has a large impedance in a high frequency range and requires a high process temperature. Since it is necessary to apply the electrolyte a number of times, there is a drawback that a leakage current defect is liable to occur essentially. In order to avoid this, every time MnO ₂ is further formed, it is necessary to perform a re-chemical treatment for repairing an oxide film as a dielectric, so that the electrolyte forming process is complicated. Further, those using TCNQ as an electrolyte layer are as follows:
TCNQ was inferior in heat resistance because it melted at a temperature lower than the solder temperature. The conductivity of TCNQ is 1 S / cm
Since the degree is limited, it has not been possible to meet the demand for a capacitor having better high frequency characteristics. Therefore, the conductivity is higher than that of MnO ₂ or TCNQ,
A solid electrolytic capacitor using a conductive polymer having higher heat resistance as an electrolyte layer has been proposed. For example, JP
Japanese Patent Publication No. 0-37114 discloses a capacitor using a conductive polymer composed of a doped five-membered heterocyclic compound polymer as an electrolyte layer. Also, JP-A-63-80517
Japanese Patent Application Laid-Open Publication No. H11-157, discloses a capacitor in which a thin film layer is formed by applying a volatile solvent solution of a heterocyclic five-membered cyclic compound polymer and a doped one is used as an electrolyte layer.

However, the method of forming an electrolyte comprising a conductive polymer described in Japanese Patent Application Laid-Open No. 60-37114 is an electrolytic polymerization method, so the process is complicated. It has been difficult in terms of mass production to form a small capacitor element. Also, conducting such electrode reactions on the dielectric surface of a capacitor that is insulative usually involves considerable difficulty. In addition, as disclosed in JP-A-63-80517, in a method of applying a volatile solvent solution of an insulated conductive polymer, a conductive polymer layer having a sufficient thickness is formed inside a capacitor element. Since it cannot be formed, the heat resistance of the capacitor is inferior, and since the conductive polymer film is too dense, the change due to stress on the process is large, and the characteristics after molding the exterior tend to decrease. .

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a solid electrolyte which is simple and has excellent capacity, internal resistance, dielectric loss, and impedance from low to high frequencies, is resistant to process stress, and has excellent heat resistance. An object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor capable of producing a capacitor.

Another object of the present invention is to provide a solid electrolytic capacitor which is excellent in capacity, internal resistance, dielectric loss and impedance from low frequency to high frequency, resistant to process stress and excellent in heat resistance. An object of the present invention is to provide a composition for forming an electrolyte of a capacitor.

Another object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor in which aniline is dissolved well.

Another object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor in which aniline can be dissolved well, the liquid can be dried well, and there is little harm to the human body.

It is another object of the present invention to provide a composition for forming an electrolyte of a solid electrolytic capacitor having a uniform thickness of the electrolyte formed by chemical oxidation polymerization.

Another object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor having excellent storage stability of a solution.

Another object of the present invention is to form a uniform and dense electrolyte layer, so that a solid electrolytic capacitor which is more resistant to process stress and resistant to thermal shock can be manufactured. It is to provide a composition.

Another object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor capable of producing a solid electrolytic capacitor that is more resistant to thermal shock.

Another object of the present invention is to provide a liquid having good drying properties,
An object of the present invention is to provide a composition for forming an electrolyte of a solid electrolytic capacitor which is less harmful to the human body.

Another object of the present invention is to provide a solid electrolytic capacitor which is easy to form an electrolyte, has high heat resistance, and has excellent capacity, internal resistance, dielectric loss and impedance from low to high frequencies. is there.

[0014]

The present invention comprises (a) a solution containing at least aniline and (b) a solution containing at least an oxidizing agent, wherein any one of (a) and (b)
Alternatively, the present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor containing an organic solvent in which both solutions are freely mixed with water.

Further, the present invention provides an organic solvent in which (A) a solution containing at least aniline is mixed with (A) aniline, (B) organic sulfonic acid, (C) water, and (D) water in a free ratio. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor, which is a solution used as an essential component.

Further, the present invention provides an organic solvent which is mixed with water as the component (D) in a free ratio, wherein the organic solvent is an alkyl alcohol, a glycol solvent, a monoether solvent, a diether solvent, a cyclic ether which can dissolve aniline. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor, comprising one or more components selected from a system solvent, a ketone solvent, a nitrogen-containing compound solvent, and a carboxylic acid ester solvent.

In the present invention, the organic solvent which is mixed with water as the component (D) at a free ratio is at least one component selected from ethanol, 1-propanol, isopropanol, propylene glycol monomethyl ether, diglyme and acetone. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor comprising:

In addition, the present invention relates to (A) a solution containing at least aniline, wherein a solution containing at least aniline is represented by the general formula (E) in addition to the essential components (A), (B), (C) and (D): 1)

[0019]

Embedded image The invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor containing a compound represented by the formula (n is an integer of 1 to 7).

The present invention also relates to the above (A) component, (C)
The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor, wherein both the component and the component (D) are degassed.

Further, the present invention provides an organic solvent in which (b) the solution containing at least an oxidizing agent is an organic solvent in which (F) ammonium peroxodisulfate, (G) water and (H) water are mixed at a free ratio as an essential component. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor, which is a solution to be dissolved.

In the present invention, the organic solvent which can be mixed with water as the component (H) at a free ratio is an alkyl alcohol, a glycol solvent, a monoether solvent, a diether solvent, a cyclic ether solvent, a ketone solvent. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor, comprising at least one component selected from a solvent, a nitrogen-containing compound-based solvent and a carboxylic acid ester-based solvent.

In the present invention, the organic solvent which can be mixed with water as the component (H) at a free ratio is selected from one or more components selected from ethanol, propanol, isopropanol, propylene glycol monomethyl ether, diglyme, acetonitrile and acetone. The present invention relates to a composition for forming an electrolyte of a solid electrolytic capacitor.

The present invention also relates to a solid electrolytic capacitor in which an electrolyte is formed using the composition for forming an electrolyte of a solid electrolytic capacitor.

The electrolyte in the present invention is a conductive substance for obtaining electrical contact between a dielectric film made of a thin oxide film formed on the surface of a metal (valve metal) used for an anode of an electrolytic capacitor and a cathode. Say.

[0026]

DETAILED DESCRIPTION OF THE INVENTION The aniline as the component (A) in the present invention has the general formula (2)

[0027]

Embedded image (Wherein, R independently represents an alkyl group, an alkenyl group, an alkoxy group, a cycloalkyl group, a cycloalkenyl group or an alkanoyl group, m is an integer of 1 to 5, n
Is an integer of 0 to 4, and m + n is 5). Preferably, R is an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, and 1 to 4 carbon atoms.
An alkyl group having 5 to 6 carbon atoms, a cycloalkenyl group having 5 to 6 carbon atoms, and an alkanoyl group having 7 to 10 carbon atoms. These are preferred in terms of solubility and the like, and among them, aniline monomers having no substituents are most preferred in that the conductivity of polyaniline obtained by chemical oxidative polymerization is increased, and the cost is low.

In the present invention, (A) the solution containing at least aniline includes (A) aniline, (B) an organic sulfonic acid, (C) water, and (D) an organic solvent that can be mixed with water in a free ratio as an essential component. Preferably, the solution is

As the organic sulfonic acid as the component (B), known organic sulfonic acids can be used without any particular limitation. However, from the viewpoints of heat resistance and conductivity of chemically oxidized and polymerized polyaniline, the following are particularly preferred.

For example, benzenesulfonic acid, toluenesulfonic acid, n-hexanesulfonic acid, n-octylsulfonic acid, dodecylsulfonic acid, cetylsulfonic acid, 4-
Dodecylbenzenesulfonic acid, camphorsulfonic acid,
Poly (vinyl) sulfonic acid, dinonylnaphthalenesulfonic acid, naphthalenesulfonic acid, p-chlorobenzenesulfonic acid, phenolsulfonic acid, phenoldisulfonic acid, trichlorobenzenesulfonic acid, 4-nitrotoluene-2-sulfonic acid, 1-octanesulfonic acid , Sulfonated polystyrene, sulfonated polyethylene, nitrobenzenesulfonic acid, 2-sulfobenzoic acid, 3-nitrobenzenesulfonic acid, 4-octylbenzenesulfonic acid,
Examples thereof include 2-methyl-5-isopropylbenzenesulfonic acid and sulfosuccinic acid. Of these, phenolsulfonic acid, phenoldisulfonic acid, 2-sulfobenzoic acid, and sulfosuccinic acid are preferred in terms of heat resistance and conductivity of chemically oxidized and polymerized polyaniline. The acid, 3-nitrobenzenesulfonic acid, is most preferred.

It is preferable that water as the component (C) does not contain ionic impurities or organic substances, and it is preferable that both ion exchange and distillation are performed.

The organic solvent as the component (D) is a solvent that can be mixed with water at a free ratio. Among them, alkyl alcohols that can dissolve aniline, glycol solvents, monoether solvents, diether solvents, cyclic ether solvents,
It is preferable to select from ketone solvents and carboxylic acid ester solvents. Specific examples of such a solvent include methanol, ethanol, n-propanol, isopropyl alcohol, lower alkyl alcohols such as t-butyl alcohol, ethylene glycol, diethylene glycol,
Glycol solvents such as triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, methyl cellosolve, ethyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, Monoether solvents such as propylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diglyme, triglyme, tetraethylene glycol dimethyl ether, etc. The -Ether solvents, tetrahydrofuran, cyclic ether solvents such as dioxane, ketone solvents such as acetone, acid ester solvents such as methyl lactate, acetonitrile, nitrogen-containing compound solvents such as N-methylpyrrolidone can be preferably used, It is also possible to use a plurality of these in combination. Among them, ethanol, propanol, isopropanol, propylene glycol monomethyl ether, diglyme, and acetone are preferred because they have low toxicity and are excellent in solubility and drying property of the component (A).

The general formula (1), which is the component (E) in the present invention,

[0034]

Embedded image In the compound represented by (n is an integer of 1 to 7), n needs to be 1 to 7. When n is larger than 7, the life of the electrolyte forming composition of the present invention is shortened, and The conductivity of the polyaniline obtained by the reaction tends to decrease. More preferred values of n are from 1 to 3, most preferably 1.

As the oxidizing agent in the present invention, those capable of polymerizing aniline such as ammonium peroxodisulfate, iron (III) chloride, ammonium dichromate, sodium dichromate and hydrogen peroxide can be used. This is preferred because the conductivity of the electrolyte layer from which ammonium disulfate is obtained is good.

In the present invention, (b) the solution containing at least the oxidizing agent is preferably a solution containing an oxidizing agent, an organic solvent which is mixed with water at a free ratio with (G) water and (H) as essential components. . In particular, it is preferable to contain (F) ammonium peroxodisulfate as the oxidizing agent.

As the ammonium peroxodisulfate as the component (F), it is preferable to use the one which has not absorbed moisture at the time before preparing the solution containing at least the oxidizing agent according to the present invention in view of the reaction activity.

It is preferable that water as the component (G) does not contain ionic impurities or organic substances, and it is preferable that both ion exchange and distillation are performed.

As the organic solvent which is the component (H) in the present invention, a type which can be mixed with water at a free ratio is used. Specific examples of such a solvent include lower alkyl alcohols such as methanol, ethanol, n-propanol, isopropyl alcohol and t-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene. Glycol solvents such as glycol, methyl cellosolve, ethyl cellosolve,
Methyl carbitol, ethyl carbitol, butyl carbitol, triethylene glycol monomethyl ether,
Monoether solvents such as triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, ethylene glycol methyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diglyme,
Diether solvents such as triglyme and tetraethylene glycol dimethyl ether; cyclic ether solvents such as tetrahydrofuran and dioxane; ketone solvents such as acetone; acid ester solvents such as methyl lactate; nitrogen-containing compounds such as acetonitrile and N-methylpyrrolidone Solvents can be preferably used, and a plurality of these can be used in combination. Among them, ethanol, propanol, isopropanol, propylene glycol monomethyl ether, diglyme, and acetone are particularly preferable because of their low toxicity and excellent drying properties.

Since acetonitrile is hardly oxidized, it is particularly preferable because (b) the solution containing at least the oxidizing agent in the present invention is excellent in storage stability and also excellent in drying property.

The solution (b) of the present invention containing at least an oxidizing agent may further contain components other than the components (F), (G) and (H). For example, an organic sulfonic acid that acts as a polyaniline dopant can be added. As such an organic sulfonic acid, any known organic sulfonic acid can be used without particular limitation, but those preferably used as the component (B) in the present invention are particularly preferable in view of heat resistance and conductivity of chemically oxidized and polymerized polyaniline. .

The compounding amount of the component (A) in the present invention is preferably from 0.2 wt% to 23 wt%, more preferably from 0.1 wt% to the total amount of the solution containing at least aniline in the present invention. 7wt% to 16wt
%, Particularly preferably 1 wt% to 12 wt%. If the amount of component (A) is less than 0.2 wt%, the thickness of the polyaniline film formed on the surface of the oxide film of the electrolytic capacitor tends to be thin, and if it exceeds 23 wt%, the film is formed on the oxide film surface of the electrolytic capacitor. The conductivity of the resulting polyaniline coating tends to decrease.

The compounding amount of the component (B) in the present invention is preferably from 0.2 wt% to 25 wt%, more preferably from 0.1 wt% to the total amount of the solution containing at least aniline in the present invention. 6wt% to 15wt
%, Particularly preferably 1 wt% to 11 wt%. If the blending amount of the component (B) is less than 0.2 wt%, the heat resistance of the polyaniline film formed on the oxide film surface of the electrolytic capacitor tends to decrease, and if it exceeds 25 wt%, at least (A) in the present invention. The viscosity of the aniline-containing solution tends to be too high, and the impregnation property of the capacitor element tends to decrease.

The compounding amount of the component (C) in the present invention is preferably from 27 wt% to 90 wt%, more preferably from 33 wt% to 85 wt%, based on the total amount of the solution containing at least aniline in the present invention. %, Particularly preferably 38 wt% to 80 wt%. If the amount of the component (C) is less than 27% by weight, the conductivity of the polyaniline film formed on the oxide film surface of the electrolytic capacitor tends to decrease, and if it exceeds 90% by weight, the dissolution of the component (E) in the present invention. Properties tend to decrease.

The compounding amount of the component (D) in the present invention is preferably from 9.5 wt% to 70 wt%, more preferably 15 wt%, based on the total amount of the solution (i) containing at least aniline in the present invention. From 60wt%
And particularly preferably from 20 wt% to 50 wt%. If the compounding amount of the component (D) is less than 9.5 wt%, the solubility of the component (A) or the component (E) of the present invention tends to decrease, and if it exceeds 50 wt%, it forms on the oxide film surface of the electrolytic capacitor. The conductivity of the resulting polyaniline coating tends to decrease.

The blending amount of the component (E) in the present invention is preferably from 0.02 wt% to 2.5 wt%, more preferably from the total amount of the solution containing at least aniline in the present invention. The content is 0.05 wt% to 1.6 wt%, particularly preferably 0.1 wt% to 1.2 wt%. (E) The compounding amount of the component is 0.02 w
If it is less than t%, the uniformity of the thickness of the polyaniline film formed on the oxide film surface of the electrolytic capacitor tends to decrease, and if it exceeds 2.5 wt%, (a) the solution of at least aniline in the present invention The stability is reduced, and the conductivity of the polyaniline film formed on the oxide film surface of the electrolytic capacitor tends to decrease.

The aniline as the component (A), the water as the component (C), and the organic solvent as the component (D) in the present invention are preferably degassed. If it is contained, the reaction of the composition for forming an electrolyte of the solid electrolyte of the present invention starts during storage of the solution (i) of the present invention containing at least aniline, or the conductivity of polyaniline obtained by chemical oxidative polymerization. Rate tends to decrease.

The compounding amount of the oxidizing agent or the component (F) in the present invention is from 0.2 wt% to 23 wt% with respect to the total amount of the solution containing at least the oxidizing agent in the present invention.
And more preferably 0.7% by weight.
To 16 wt%, particularly preferably 1 wt% to 1 wt%.
2 wt%. If the amount of the oxidizing agent or the component (F) is less than 0.2 wt%, the thickness of the polyaniline film formed on the surface of the oxide film of the electrolytic capacitor tends to be thin. The conductivity of the polyaniline film formed on the surface tends to decrease.

The compounding amount of the component (G) in the present invention is preferably from 30 wt% to 95 wt%, more preferably from 35 wt%, based on the total amount of the solution containing at least the oxidizing agent in the present invention. The content is 90 wt%, particularly preferably 40 to 85 wt%.
If the compounding amount of the component (G) is less than 30 wt%, the solubility of the oxidizing agent or the component (F) in the present invention tends to decrease. Coatings tend to be non-uniform and vulnerable to stress and thermal shock.

The compounding amount of the component (H) in the present invention is preferably from 4 wt% to 69 wt%, more preferably from 10 wt%, based on the total amount of the solution containing at least the oxidizing agent in the present invention. It is 60 wt%, particularly preferably 20 to 50 wt%.
If the compounding amount of the component (H) is less than 4 wt%, the polyaniline film formed on the oxide film surface of the electrolytic capacitor becomes non-uniform, and tends to be weak against stress and thermal shock.
If the amount exceeds wt%, the solubility of the oxidizing agent of the present invention or the component (F) tends to decrease.

In the solution (B) of the present invention containing at least the oxidizing agent, the compounding amount of the components other than the components (F), (G) and (H) depends on the amount of the solution (B) of the present invention containing at least the oxidizing agent. It is preferably less than 25 wt%, more preferably less than 15 wt%, and particularly preferably less than 5 wt% based on the total amount. (F),
25 wt% of components other than the components (G) and (H)
Above, the oxidative polymerization reaction of aniline is inhibited, and the conductivity of the polyaniline film formed on the oxide film surface of the electrolytic capacitor tends to decrease.

The valve metal used for the solid electrolytic capacitor of the present invention is aluminum, tantalum, niobium, vanadium,
Titanium, zirconium and the like can be mentioned, but an expanded aluminum foil or a tantalum sintered body is preferable from the viewpoints of permittivity and easy formation of an oxide film.

The method for forming an oxide film on the surface of the valve metal in the solid electrolytic capacitor of the present invention can be used without any particular limitation as long as it is a method usually used at the time of manufacturing an electrolytic capacitor. A known method such as forming an oxide film by applying a voltage to an aluminum foil in an aqueous solution of ammonium adipate, or forming an oxide film by applying a voltage to a tantalum fine powder sintered pellet in an aqueous solution of nitric acid is used. Can be

As a preferable method of manufacturing the solid electrolytic capacitor of the present invention, for example, an element having an oxide film formed on a valve metal is impregnated with the solution containing at least the oxidizing agent according to the present invention, and then dried. Alternatively, after the element which is not dried is impregnated with (i) the solution containing at least aniline in the present invention and the polymerization of polyaniline is performed, the step of drying the element is repeated once to several tens of times, and then further dried to remove water and the like. Is volatilized, an electrolyte layer is formed, a carbon paste layer and a silver paste layer are formed in this order on the electrolyte layer, and the element is adhered to a lead frame or the like with a conductive adhesive. There is a method of sealing and enclosing with a sealing material.

[0055]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Degassed aniline (reagent, Wako Pure Chemical Industries, Ltd.) obtained by bubbling with nitrogen for 30 minutes, degassed ion-exchanged water, degassed ethanol (Wako Pure Chemical Industries, Ltd.) , Degassed reagents) and aniline dimer (para-aminodiphenylamine, Wako Pure Chemical Industries, Ltd., reagent), and phenolsulfonic acid (Wako Pure Chemical Industries, Ltd., reagent), ammonium peroxodisulfate (Wako Pure Chemical Industries, Ltd.) Using an industrial (reagent), a composition for forming an electrolyte of a solid electrolytic capacitor of Example 1 having the composition shown in Table 1 was obtained. Next, a solid electrolytic capacitor of Example 1 was obtained by the following method.

FIG. 2 is a sectional view of a solid electrolytic capacitor of the present invention using tantalum as a valve metal.

A prism-shaped sintered compact of tantalum fine powder having a length of 1 mm, a depth of 1 mm and a height of 1 mm (porosity of 60
%, A designed capacity of 3.3 μF), an oxide film was formed in a nitric acid aqueous solution at 20 V, and a tantalum pellet 12 having a tantalum oxide film 15 formed on the surface of a tantalum 16 was produced. Among the compositions for forming the electrolyte of the solid electrolytic capacitor of the present invention shown in the drawing, (b) impregnated with a solution containing at least an oxidizing agent,
After drying at 20 ° C. for 20 minutes, the composition for forming an electrolyte of the solid electrolytic capacitor of the present invention shown in Table 1 was impregnated with (a) a solution containing at least aniline, and left at room temperature for 10 minutes. At 80 ° C. for 20 minutes. This impregnation step was repeated 20 times to form an electrolyte layer 19 made of polyaniline. Further, a carbon paste layer 17 and a silver paste layer 18 were sequentially formed on the electrolyte layer 19. A cathode lead 11 is connected to the silver paste layer 18 using a silver paste, an anode 13 is connected to a tantalum wire 14, and the package is molded with a sealing material 10. A capacitor was obtained. Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor. The measurement of electrical characteristics is made by HEWLETT PACKARD 419
This was performed using a 2ALF type impedance analyzer. Table 2 also shows the characteristics of a conventional tantalum solid electrolytic capacitor using manganese dioxide for the electrolyte layer.

Example 2 In the composition of the composition for forming an electrolyte of the solid electrolytic capacitor of Example 1, the point that the isopropanol (reagent, Wako Pure Chemical Industries, Ltd.) was used instead of ethanol and the mixing ratio were changed. Except for the above, in the same manner as in Example 1, the composition for forming an electrolyte for a solid electrolytic capacitor of Example 2 was obtained. Further, a solid electrolytic capacitor of Example 2 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 2 was used. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 3 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 1, diglyme was used instead of ethanol and the mixing ratio was changed, and 2-sulfoic acid was used instead of phenolsulfonic acid. A composition for forming an electrolyte for a solid electrolytic capacitor of Example 3 was obtained in the same manner as in Example 1 except that benzoic acid (Aldrich, reagent) was used. A solid electrolytic capacitor of Example 3 was obtained in the same manner as in Example 1, except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 3 was used and the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor,
Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 4 In the composition of the electrolyte composition of the solid electrolytic capacitor of Example 1, acetone (Wako Pure Chemical Industries, Ltd., reagent) was used instead of ethanol, and the mixing ratio was changed. A composition for forming an electrolyte for a solid electrolytic capacitor of Example 4 was obtained in the same manner as Example 1 except for the above. Further, the point of using the composition for forming an electrolyte for a solid electrolytic capacitor of Example 4,
A solid electrolytic capacitor of Example 4 was obtained in the same manner as in Example 1 except that the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 5 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 1, the point that 1-propanol (reagent, Wako Pure Chemical Industries, Ltd.) was used instead of ethanol and the mixing ratio were changed. The procedure of Example 5 was repeated, except that 3-nitrobenzenesulfonic acid (Tokyo Kasei Kogyo Co., Ltd., reagent) was used instead of phenolsulfonic acid. A composition was obtained. Further, a solid electrolytic capacitor of Example 5 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 5 was used and the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor,
Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 6 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 1, the point that propylene glycol monomethyl ether was used instead of ethanol, the point that p-aminodiphenylamine was not used, and the mixing ratio were changed. A composition for forming an electrolyte for a solid electrolytic capacitor of Example 6 was obtained in the same manner as in Example 1 except for the point that the above process was performed. In addition, the point of using the composition for forming an electrolyte for a solid electrolytic capacitor of Example 6, the point that the room temperature standing time after impregnating the composition for forming an electrolyte of a solid electrolytic capacitor of the present invention was set to 1 hour, The solid electrolytic capacitor of Example 6 was obtained in the same manner as in Example 1 except for changing. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 7 A composition for forming an electrolyte for a solid electrolytic capacitor of Example 7 was obtained in the same manner as in Example 1. Next, a solid electrolytic capacitor of Example 7 was obtained by the following method.

FIG. 1 is a sectional view of a solid electrolytic capacitor of the present invention using aluminum as a valve metal. First, a film thickness of 70 μm ( ² μF / cm ² ) expanded by etching,
An aluminum etched foil 1 having an area of 1 cm × 1.2 cm (welding margin: 0.2 cm: effective area: 1 cm ² ) was heated at 60 ° C.
The oxide film 3 was formed in a 10% ammonium adipate aqueous solution at 40 V. Next, the lead terminal 2 was welded to the aluminum foil thus formed with the oxide film. Next, the aluminum foil on which the oxide film was formed was immersed in a solution containing (b) at least an oxidizing agent among the electrolyte forming compositions of the solid electrolytic capacitor of the present invention shown in Table 1, and heated at 80 ° C. with a hot air drier. And then dipped in a solution containing at least aniline among the electrolyte forming compositions of the solid electrolytic capacitor of the present invention shown in Table 1, left at room temperature for 10 minutes, and then heated with a hot air drier. Dry at 80 ° C. for 20 minutes. This step was repeated 20 times to form the electrolyte layer 4 made of polyaniline. Further, a carbon paste layer 5 and a silver paste layer 6 were sequentially formed, and a cathode lead 8 was connected to the silver paste layer 6 using a silver paste 7, and the package was impregnated with an epoxy resin 9 and aluminum was used as a valve metal. The solid electrolytic capacitor of the present invention was obtained. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor. Table 2 also shows the characteristics of a conventional aluminum electrolytic capacitor using an electrolyte solution for the electrolyte layer.

Example 8 The composition of the composition for forming an electrolyte of a solid electrolytic capacitor of Example 1 was the same as (b) except that ethanol was also added to a solution containing at least an oxidizing agent and the mixing ratio was changed. In the same manner as in Example 1, the composition for forming an electrolyte for a solid electrolytic capacitor of Example 8 was obtained. A solid electrolytic capacitor of Example 8 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 8 was used. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 9 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 8, (b) isopropanol (reagent, Wako Pure Chemical Industries, Ltd.) was used instead of ethanol in a solution containing at least an oxidizing agent. In the same manner as in Example 8 except that the composition was changed and the mixing ratio was changed, a composition for forming an electrolyte for a solid electrolytic capacitor of Example 9 was obtained. A solid electrolytic capacitor of Example 9 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 9 was used. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 10 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 8, (b) diglyme was used instead of ethanol in a solution containing at least an oxidizing agent, and (a) at least aniline was used. Except that 2-sulfobenzoic acid (Aldrich, reagent) was used instead of phenolsulfonic acid in the solution containing, and that the blending ratio was changed, the solid electrolytic capacitor of Example 10 was used in the same manner as in Example 8. An electrolyte forming composition was obtained. Further, a solid electrolytic capacitor of Example 10 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 10 was used and the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 11 In the composition of the electrolyte forming composition of the solid electrolytic capacitor of Example 8, (b) acetone (reagent, Wako Pure Chemical Industries, Ltd.) was used instead of ethanol in a solution containing at least an oxidizing agent.
Example 11 was obtained in the same manner as in Example 8, except that phenolsulfonic acid was added and the mixing ratio was changed. Further, a solid electrolytic capacitor of Example 11 was obtained in the same manner as in Example 1, except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 11 was used and the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 12 In the composition of the composition for forming an electrolyte of a solid electrolytic capacitor of Example 8, (b) 1-propanol (Wako Pure Chemical Industries, Ltd.) was used instead of ethanol in a solution containing at least an oxidizing agent. (A) 3-nitrobenzenesulfonic acid (Tokyo Kasei Kogyo Co., Ltd., reagent) instead of phenolsulfonic acid in a solution containing at least aniline
In Example 12, a composition for forming an electrolyte for a solid electrolytic capacitor was obtained in the same manner as in Example 8, except that the composition was changed and the mixing ratio was changed. Further, a solid electrolytic capacitor of Example 12 was obtained in the same manner as in Example 1 except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 12 was used and the number of times of impregnation was changed. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 13 In the composition of the composition for forming an electrolyte of a solid electrolytic capacitor of Example 8, (b) acetonitrile was used instead of ethanol in a solution containing at least an oxidizing agent, and p-aminodiphenylamine was used. A composition for forming an electrolyte for a solid electrolytic capacitor of Example 13 was obtained in the same manner as in Example 8, except that no point was present and the mixing ratio was changed. Further, the number of times of impregnation was changed in that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 13 was used, and that (a) the time of standing at room temperature after impregnating with a solution containing at least aniline was 1 hour. Except for the above, a solid electrolytic capacitor of Example 13 was obtained in the same manner as Example 1. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Example 14 In the same manner as in Example 8, the composition for forming an electrolyte for a solid electrolytic capacitor of Example 14 was obtained. Next, a solid electrolytic capacitor of the present invention using aluminum of Example 14 as a valve metal was obtained in the same manner as in Example 7, except that the composition for forming an electrolyte for a solid electrolytic capacitor of Example 14 was used. Table 1 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 2 shows the electrical characteristics of the obtained solid electrolytic capacitor.
Shown in

Comparative Example 1 A solid electrolytic capacitor using tantalum of Comparative Example 1 as a valve metal was produced in the same manner as in Example 3 except that an organic solvent which was mixed with water at a free ratio in the present invention was not used. Table 3 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 4 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Comparative Example 2 A solid electrolytic capacitor using tantalum as a valve metal in Comparative Example 2 was prepared in the same manner as in Example 1 except that aniline was not used and the mixing ratio was changed. could not.

Comparative Example 3 Example 1 was repeated except that ethyl ether (reagent, Wako Pure Chemical Industries, Ltd.) having the property of not dissolving in water was used in place of the organic solvent mixed in a free ratio with water in the present invention. In the same manner as in Example 1, a solid electrolytic capacitor using tantalum of Comparative Example 3 as a valve metal was produced. Table 3 shows the composition of the composition for forming an electrolyte of the obtained solid electrolytic capacitor, and Table 4 shows the electrical characteristics of the obtained solid electrolytic capacitor.

Comparative Example 4 Example 8 was repeated except that ethyl ether having a property of not dissolving in water (reagent, Wako Pure Chemical Industries, Ltd.) was used in place of the organic solvent mixed in a free ratio with water in the present invention. In the same manner as in Example 1, a solid electrolytic capacitor using tantalum of Comparative Example 4 as a valve metal was produced, but no electrolyte could be formed.

COMPARATIVE EXAMPLE 5 N-methyl-2-containing 2% by weight of polyaniline powder
The step of impregnating and drying the pyrrolidone solution in the tantalum pellets on which the oxide film was formed in the same manner as in Example 1 was carried out in 20 steps.
After repeating twice, the aqueous solution of phenolsulfonic acid is
C. for 5 hours, and then washed with acetone to form an electrolyte layer. Further, a carbon paste layer and a silver paste layer were sequentially formed, a cathode lead was connected to the silver paste layer using a silver paste, and the package was molded with a sealing material, and tantalum was used as a valve metal. An electrolytic capacitor was obtained. Table 4 shows the electrical characteristics of the obtained solid electrolytic capacitor of Comparative Example 5.

[0078]

[Table 1]

[0079]

[Table 2] * Based on JIS C5102. -55 ° C to 20 ° C to 8
5 ° C, 5 cycles.

[0080]

[Table 3]

[0081]

[Table 4] * Based on JIS C5102. -55 ° C to 20 ° C to 8
5 ° C, 5 cycles.

As is clear from comparison of Tables 2 and 4, the solid electrolytic capacitor according to the embodiment has lower low frequency characteristics and high frequency characteristics than the solid electrolytic capacitor according to the comparative example and the solid electrolytic capacitor according to the conventional example. It was excellent.

[0083]

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention is simple and excellent in capacity, internal resistance, dielectric loss, and impedance from low to high frequencies, resistant to process stress, and resistant to heat. Since an excellent solid electrolytic capacitor can be produced, it is suitable as a composition for forming an electrolyte of a solid electrolytic capacitor.

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention is excellent in capacity, internal resistance, dielectric loss and impedance from low to high frequencies, resistant to process stress, and excellent in heat resistance. Capacitors can be made.

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention is excellent in aniline dissolving power.

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention has a good dissolving power for aniline, a good drying property of the liquid, and a small harm to the human body.

In the composition for forming an electrolyte of a solid electrolytic capacitor of the present invention, the thickness of the electrolyte formed by chemical oxidation polymerization becomes uniform.

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention is excellent in storage stability of a solution.

The composition for forming an electrolyte of a solid electrolytic capacitor of the present invention can form a uniform and dense electrolyte layer, and can produce a solid electrolytic capacitor that is more resistant to process stress and resistant to thermal shock.

The composition for forming an electrolyte of a solid electrolytic capacitor of the present invention can produce a solid electrolytic capacitor that is more resistant to thermal shock.

The composition for forming an electrolyte of a solid electrolytic capacitor according to the present invention has good drying properties of liquid and has little harm to the human body.

The solid electrolytic capacitor of the present invention has a simple electrolyte formation, high heat resistance, and excellent capacity, internal resistance, dielectric loss, and impedance from low to high frequencies.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of the solid electrolytic capacitor of the present invention.

FIG. 2 is a cross-sectional view of an example of the solid electrolytic capacitor of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum etching foil 2 Lead terminal 3 Oxide film 4 Electrolyte layer 5 Carbon paste layer 6 Silver paste layer 7 Silver paste 8 Cathode lead 9 Epoxy resin 10 Sealant 11 Cathode 12 Tantalum pellet 13 Anode 14 Tantalum wire 15 Tantalum oxide film 16 Tantalum 17 carbon paste layer 18 silver paste layer 19 electrolyte layer

Claims (10)

[Claims] (1) a solution containing at least aniline,
And (b) a solid electrolytic capacitor comprising an organic solvent comprising at least two solutions of at least an oxidizing agent, wherein either (a) or (b) or both of the solutions contain an organic solvent that is freely mixed with water. A composition for forming an electrolyte. 2. A solution containing at least aniline comprising: (A) 0.2 to 23% by weight of aniline;
A solution containing, as essential components, an organic solvent which is freely mixed with 2 to 25% by weight of organic sulfonic acid, (C) 27 to 90% by weight of water and (D) 9.5 to 70% by weight of water. The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 1. 3. An organic solvent which can dissolve aniline in an organic solvent which can be mixed with water as a component (D) in a free ratio, an alkyl alcohol, a glycol solvent, a monoether solvent, a diether solvent, a cyclic ether solvent, and a ketone solvent. 3. The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 2, comprising one or more components selected from a nitrogen-containing compound solvent and a carboxylic acid ester solvent. 4. The organic solvent which is mixed in a free ratio with water as the component (D) comprises at least one component selected from ethanol, 1-propanol, isopropanol, propylene glycol monomethyl ether, diglyme and acetone. The composition for forming an electrolyte of a solid electrolytic capacitor as described in the above. 5. A solution containing at least aniline as a component (E) of the general formula (1). The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 2, comprising a compound represented by the formula (n is an integer of 1 to 7). 6. The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 2, wherein the components (A), (C) and (D) are all degassed. 7. (b) The solution containing at least an oxidizing agent,
(F) 0.2-23% by weight ammonium peroxodisulfate, (G) 30-95% by weight water and (H) 4-69.
2. The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 1, wherein the composition is a solution containing an organic solvent that is freely mixed with water by weight as an essential component. 8. An organic solvent which is mixed at a free ratio with water as the component (H) is an alkyl alcohol, a glycol solvent, a monoether solvent, a diether solvent, a cyclic ether solvent, a ketone solvent, a nitrogen-containing compound. The composition for forming an electrolyte of a solid electrolytic capacitor according to claim 7, comprising one or more components selected from a system solvent and a carboxylate ester solvent. 9. The organic solvent which is mixed with water as the component (H) in a free ratio comprises at least one component selected from ethanol, propanol, isopropanol, propylene glycol monomethyl ether, diglyme, acetonitrile and acetone. The composition for forming an electrolyte of a solid electrolytic capacitor as described in the above. 10. The method of claim 1, 2, 3, 4, 5, 6, 7,
10. A solid electrolytic capacitor in which an electrolyte is formed from the composition for forming an electrolyte of a solid electrolytic capacitor according to 8 or 9.