JPH11186106A - Paste composition for solid electrolyte and manufacture of solid electrolytic capacitor using this composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a heat decomposition process and decomposition gas treatment and obtain a prescribed film pressure by one coating step, by using manganese dioxide powder, dispersed resin and an organic solvent as essential components. SOLUTION: Manganese dioxide powder, dispersed resin and an organic solvent are used as essential components. As the manganese dioxide powder, for example, powders having α, β and γcrystal structures may be used, preferably the manganese dioxide powder having the β crystal structure, considering conductivity. Though the dispersed resin is not specially limited, as far as it improves the dispersion of manganese dioxide powder, soluble to organic solvent and easily binds with manganese dioxide powder after drying the paste, a thermoplastic resin is preferable. The organic solvent is not specially limited, as far as it solves the dispersed resin and maintains dispersion stability of the manganese dioxide powder. Solvents such as alicyclic ketonic compound are preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste composition for forming a solid electrolyte which forms a stable coating film when an electrode layer is formed on an electronic component such as a capacitor, and the production of a solid electrolytic capacitor using the same. About the method.

[0002]

2. Description of the Related Art Conventionally, a method of thermally decomposing a manganese nitrate solution has been adopted for forming a solid electrolyte for electronic parts such as a tantalum capacitor. In this method, a device is immersed in a manganese nitrate aqueous solution, and then a manganese dioxide layer is formed through a thermal decomposition process called chemical formation. At this time, since the thickness of the coating film that can be formed at a time is very small, it is necessary to repeat the thermal decomposition process ten or more times in order to form an electrolyte layer having a predetermined thickness. The disadvantage is that the energy cost is very high. Further, in order to thermally decompose the manganese nitrate, NO _X occurs in the pyrolysis process, has a problem that will process the need for these cracked gas.

Regarding these problems, Japanese Patent Laid-Open Publication No.
No. 559 discloses a method of mixing manganese dioxide powder into a volatile solvent such as water, alcohol, thinner, carbon tetrachloride, and ammonium carbonate. However, this method has the drawback that the manganese dioxide powder in the solution is hardly dispersed, and the particles coagulate and settle during storage, so that a uniform coating film cannot be obtained. JP-A-7-2323
Japanese Patent Publication No. 98 discloses a method of replacing a part of the metal powder used in the conductive paste with manganese dioxide powder. However, this method has a problem that properties as a solid electrolyte are not sufficiently exhibited. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a paste composition for forming a solid electrolyte, which makes up the above-mentioned drawbacks and makes it difficult for manganese dioxide powder to settle out and can form a uniform coating film. . According to the first aspect of the present invention, there is provided a paste for forming a solid electrolyte, which can omit a thermal decomposition step and a treatment of a decomposition gas when forming a solid electrolyte layer and can obtain a predetermined film thickness by one application. It provides a composition. The invention according to claim 2 is to improve the dispersion stability of the filler during storage of the paste, and to improve the strength of the coating film during curing of the paste and the adhesion to the base material, in addition to the invention according to claim 1. An object of the present invention is to provide a paste composition for forming a solid electrolyte capable of improving the property.
According to the third aspect of the present invention, in addition to the first aspect of the present invention, it is possible to improve the uniformity of the coating film by limiting the particle size of the manganese dioxide powder, and to produce a coating film having a uniform film quality. A paste composition for forming a solid electrolyte is provided.
The invention according to claim 4 is a solid electrolyte-forming paste composition capable of improving the conductivity of the manganese dioxide powder itself and reducing the resistance of the coating film by making the crystal structure of the manganese dioxide powder β-type. Is provided. The invention described in claim 5 is to provide a paste composition for forming a solid electrolyte which can improve the strength of a coating film and form a stable coating film by using a thermoplastic resin as a dispersing resin. According to the invention of claim 6, in addition to the invention of claim 5, by using a resin having a glass transition temperature of 140 to 260 ° C. as the dispersing resin, a heat-resistant and thermally stable coating film is formed. It is intended to provide a paste composition for forming a solid electrolyte, which can be used. The invention according to claim 7 provides a method for manufacturing a solid electrolytic capacitor using the paste composition for forming a solid electrolyte according to any one of claims 1 to 6.

[0005]

A paste composition for forming a solid electrolyte comprising (A) manganese dioxide powder, (B) a dispersing resin and (C) an organic solvent as essential components, and a method for producing a solid electrolytic capacitor using the same. About.

Further, the present invention provides a paste composition for forming a solid electrolyte comprising (A) a manganese dioxide powder, (B) a dispersion resin and (C) an organic solvent, having an average particle size of 0.0
It is preferable to disperse a manganese dioxide powder having a β-type crystal structure of 1 to 10 μm in an organic solvent in the presence of a coupling agent, using a thermoplastic resin as a dispersion resin.

[0007]

Next, a conductive paste composition of the present invention capable of forming a solid electrolyte layer and a method of manufacturing a solid electrolytic capacitor using the same will be described in detail. Examples of the manganese dioxide powder (A) in the present invention include powders having α, β, and γ crystal structures, and manganese dioxide powder having a β-type crystal structure is preferable in consideration of conductivity. Manganese dioxide having a β-type crystal structure can be easily obtained by heating at 350 ° C. to 450 ° C. for several hours. The average particle diameter of the manganese dioxide powder is 0.01 to 50 μm in consideration of conductivity, applicability of paste, and the like.
m, but preferably from 0.01 to 10 μm. Examples of the shape of the manganese dioxide powder include, but are not limited to, spherical, irregular, and crushed shapes.

(A) The compounding amount of the manganese dioxide powder is as follows:
(A) manganese dioxide powder, (B) dispersed resin and (C)
The total amount of the organic solvent is preferably 5 to 500 parts by weight, more preferably 20 to 200 parts by weight, and particularly preferably 50 to 150 parts by weight.
If the amount is less than 5 parts by weight, it is difficult to form a coating film,
There is a tendency that the function as a solid electrolyte cannot be sufficiently exhibited. On the other hand, when the amount exceeds 500 parts by weight, the applicability as a paste and the adhesiveness to a substrate tend to decrease.

The dispersing resin (B) in the present invention is intended to improve the dispersibility of the manganese dioxide powder, and should be soluble in an organic solvent and easily bind to the manganese dioxide powder after drying the paste. Although not particularly limited, a thermoplastic resin is preferred. As the thermoplastic resin, an acrylic resin, a saturated polyester resin, a styrene resin, a polyimide resin, a polyamide resin, a polycarbonate resin, a polyamideimide resin, a polyetheramide resin, or the like is used, but is not limited thereto. Not something.

Among the above-mentioned thermoplastic resins, any of the conventionally known thermoplastic saturated polyester resins can be used as the saturated polyester, but those having a hydroxyl group or a carboxyl group at the terminal of the molecular chain may be used. When used in combination with the above resin system, it is easy to react and more effective. In addition, thermoplastic polyimide resins such as polyimide resins and polyether amide resins, and thermoplastic polyether amide resins can also be used, but polyamide obtained by polycondensing an aromatic dicarboxylic acid or a reactive acid derivative thereof with a diamine. A polyamideimide polymer obtained by polycondensing a polymer, an aromatic tricarboxylic acid or a reactive derivative thereof with a diamine is preferred. The glass transition temperature of these polymers can be adjusted by selecting various diamine components.

[0011] Examples of the thermoplastic resin having a glass transition temperature of 140 to 260 ° C include a polyimide resin and a polyetheramide resin, and among them, a polyetheramide resin is preferable. The above thermoplastic resin can be used in combination with a compatible thermoplastic resin. Further, the above-mentioned thermoplastic resin can be dissolved in an organic solvent to form a varnish.

In the present invention, the compounding amount of the (B) dispersing resin is 0.1 to 100 parts by weight of (A), (B) and (C).
The amount is preferably 5 to 40 parts by weight, more preferably 1 to 20 parts by weight, and particularly preferably 2 to 10 parts by weight. If the amount is less than 0.5 part by weight, the dispersion of manganese dioxide becomes insufficient, and a uniform coating film tends not to be formed. If the amount exceeds 40 parts by weight, the conductivity is remarkably reduced, and the function as a solid electrolyte tends not to be exhibited.

The organic solvent (C) in the present invention includes:
There is no particular limitation as long as the dispersing resin can be dissolved and the dispersion stability of the manganese dioxide powder can be maintained, but 1-methyl-2-pyrrolidone, N, N-dimethylformamide,
Polar solvents such as N, N-diethylformamide, dimethyl sulfoxide, nitrobenzene and glycol carbonate; ethylene glycol ether compounds such as diethylene glycol dimethyl ether and ethylene glycol methyl ether acetate; propylene glycol monomethyl ether; propylene glycol methyl ether acetate and the like Solvents such as propylene-based glycol ether compounds, alicyclic ketone compounds such as 2-cyclohexanone and 4-methyl-2-cyclohexanone are preferred.

In the present invention, the amount of the organic solvent (C) is 10 parts by weight based on 100 parts by weight of (A), (B) and (C).
The amount is preferably from 200 to 200 parts by weight, more preferably from 15 to 100 parts by weight, and particularly preferably from 20 to 80 parts by weight. If the amount is less than 10 parts by weight, the dispersion of the manganese dioxide powder becomes insufficient, and a uniform coating film tends not to be formed. If the amount exceeds 200 parts by weight, the thickness of the coating film tends to be too thin, and it is difficult to obtain a sufficient thickness at one time.

In the present invention, the use of a coupling agent is effective for the stable dispersion of manganese dioxide. Examples of the method of using the coupling agent include a method in which the coupling agent is directly added to a solid electrolyte forming paste and a method in which manganese dioxide powder is treated with a coupling agent and used.
As a method of treating manganese dioxide powder, for example,
A method in which a coupling agent is directly added to manganese dioxide powder and mixed with stirring (dry processing method), or a method in which the coupling agent is dissolved in a solvent such as hexane or toluene in advance, manganese dioxide powder is put in the mixture, and the mixture is stirred. For removing and drying (wet processing method).

The coupling agent is not particularly limited, as long as the manganese dioxide powder can be easily blended with the resin and the dispersion stability can be improved when the manganese dioxide powder is dispersed in an organic solvent with a dispersing resin. However, silane-based, aluminum-based, titanate-based, and zirconium-based coupling agents are preferred.

The amount of the coupling agent to be added is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 5 parts by weight, particularly preferably 0.5 to 2 parts by weight based on 100 parts by weight of the manganese dioxide powder. preferable. The amount of coupling agent added is 0.1
If the amount is less than parts by weight, the dispersibility of manganese dioxide is reduced, causing agglomeration, and the function as a paste tends to be significantly reduced. If it exceeds 10 parts by weight, the conductivity of the surface of the manganese dioxide powder is significantly reduced, and the function as a solid electrolyte layer tends to be reduced.

The paste composition for forming a solid electrolyte according to the present invention may be, for example, an antioxidant or a chelating agent, or any other additive having various functions, as long as it does not adversely affect the properties of the cured product when formed into a paste and a coating film. Addition of a modifier or the like may be performed. Further, carbon black, graphite carbon, or the like can be used in combination to impart conductivity. The amount used at this time is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the manganese dioxide powder.

The paste composition for forming a solid electrolyte of the present invention is prepared by mixing a predetermined amount of (A) manganese dioxide powder, (B) a dispersion resin and (C) an organic solvent with an ordinary stirrer, triturator,
It can be easily obtained by uniformly kneading or dispersing using a roll, a roll mill or the like.

As described above, the paste composition for forming a solid electrolyte can obtain a uniform and thick coating film by one application without changing the characteristics as a solid electrolyte. Can be suitably used as a solid electrolyte layer or the like.

The present invention relates to a method for producing a solid electrolytic capacitor using the paste composition for forming a solid electrolyte.
For example, an anode body is formed by compression molding and firing a metal powder having a valve action, and an oxide film is formed on the surface of the anode body by a chemical conversion treatment. Thereafter, the solid electrolyte layer is formed by applying and drying the paste composition for solid electrolyte formation of the present invention or by thermally decomposing an aqueous solution of manganese nitrate and using the paste composition for solid electrolyte formation of the present invention in combination.
Next, a cathode layer is formed with a carbon paste, a silver paste, or the like, connected to a cathode lead frame, and then resin-molded to manufacture a solid electrolytic capacitor.

[0022]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited by these examples.

Example 1 Manganese dioxide powder having a β-type crystal structure obtained by a heat treatment (RB-A: average particle size: 2 μm, manufactured by Mitsui Kinzoku Mining Co., Ltd.) 1
100 parts by weight of n-hexane 60 parts by weight and Plenact AL-M (Ajinomoto, aluminum-based coupling agent) 1
A part by weight was added, and the mixture was stirred and mixed by a roll mill. Thereafter, n-hexane was removed to obtain a surface-treated manganese dioxide powder. 5 parts by weight of a polyetheramide resin (Hymal, manufactured by Hitachi Chemical Co., Ltd.) and 40 parts by weight of diethylene glycol dimethyl ether obtained by polycondensation of terephthalic acid chloride and aromatic diamine are mixed with 100 parts by weight of the above manganese dioxide powder in a mortar. After premixing in the mixture, the mixture was kneaded with three rolls to obtain a paste composition for forming a solid electrolyte. Conductivity, dispersibility of this paste composition for forming a solid electrolyte,
Table 1 shows the results of measuring the coating film thickness.

The conductivity is about 50 μm by screen printing.
m was formed on an aluminum plate and, after curing, measured using a surface resistance meter. Dispersibility is measured using a grain gauge according to JIS-
It was measured according to the method of K5400. The coating thickness was measured by dipping a 1 × 2 cm ceramic plate into the paste after dipping for about 3 seconds, drying and measuring the coating thickness using a micrometer.

Example 2 A paste composition for forming a solid electrolyte was obtained in the same manner as in Example 1 except that the manganese dioxide powder having a β-type crystal structure obtained by heating had an average particle diameter of 20 μm. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 3 A paste composition for forming a solid electrolyte was obtained in the same manner as in Example 1 except that a saturated polyester resin (Vylon 200, manufactured by Toyobo) was used as the dispersion resin. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 4 A paste composition for forming a solid electrolyte was obtained in the same manner as in Example 1 except that the manganese dioxide powder having a β-type crystal structure obtained by heating was not subjected to a surface treatment with a coupling agent. Was. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 5 Example 1 was repeated except that a silane coupling agent (SH6040: manufactured by Dow Corning Toray Co., Ltd.) was used for surface treatment of manganese dioxide powder having a β-type crystal structure obtained by heating. In the same manner, a paste composition for forming a solid electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 6 Example 1 was repeated except that a silane coupling agent (KBM-303: manufactured by Shin-Etsu Silicone Co., Ltd.) was used for the surface treatment of the manganese dioxide powder having a β-type crystal structure obtained by heating. In the same manner, a paste composition for forming a solid electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 7 The procedure of Example 1 was repeated, except that a titanate coupling agent (KR-38S: manufactured by Ajinomoto Co.) was used for the surface treatment of the manganese dioxide powder having a β-type crystal structure obtained by heating. Thus, a paste composition for forming a solid electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 8 A solid was prepared in the same manner as in Example 1 except that a titanate-based coupling agent (KRTTS: manufactured by Ajinomoto Co.) was used for the surface treatment of the manganese dioxide powder having a β-type crystal structure obtained by heating. A paste composition for forming an electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 9 The procedure of Example 1 was repeated, except that a zirconium-based coupling agent (C: manufactured by Kusumoto Kasei Co., Ltd.) was used for the surface treatment of the manganese dioxide powder having a β-type crystal structure obtained by heating. A paste composition for forming a solid electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 10 The procedure of Example 1 was repeated, except that a titanate coupling agent (M1 manufactured by Kusumoto Kasei Co., Ltd.) was used for the surface treatment of the manganese dioxide powder having a β-type crystal structure obtained by heating. A paste composition for forming a solid electrolyte was obtained. Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

Example 11 A paste composition for forming a solid electrolyte was prepared in the same manner as in Example 1 except that a manganese dioxide powder having a γ-type crystal structure was used instead of the manganese dioxide powder having a β-type crystal structure of Example 1. I got Table 1 shows the measurement results of the conductivity, dispersibility, and coating film thickness of the paste composition for forming a solid electrolyte.

COMPARATIVE EXAMPLE 1 5 was used without using a paste in which manganese dioxide powder was dispersed.
Table 1 shows the results obtained by forming a manganese dioxide layer on a ceramic substrate by a conventional method of thermally decomposing a 0% by weight aqueous solution of manganese nitrate, and examining the conductivity and the coating film thickness.

The solid electrolyte forming paste composition according to the present invention has good dispersibility and excellent conductivity from the results shown in Table 1, and can obtain a predetermined film thickness by one application.

[0037]

[Table 1]

[0038]

According to the first aspect of the present invention, it is possible to omit the thermal decomposition step and the treatment of the decomposition gas when forming the solid electrolyte layer, and to obtain a predetermined film thickness by one application. A paste composition for forming a solid electrolyte is provided. The invention according to claim 2 is to improve the dispersion stability of the filler during storage of the paste, and to improve the strength of the coating film during curing of the paste and the adhesion to the base material, in addition to the invention according to claim 1. An object of the present invention is to provide a paste composition for forming a solid electrolyte capable of improving the property. The invention according to claim 3 further improves the uniformity of the coating film by limiting the particle size of the manganese dioxide powder, in addition to the invention according to claim 1,
An object of the present invention is to provide a paste composition for forming a solid electrolyte capable of producing a coating film having a uniform film quality. The invention according to claim 4 improves the conductivity of the manganese dioxide powder itself by making the crystal structure of the manganese dioxide powder β-type,
An object of the present invention is to provide a paste composition for forming a solid electrolyte capable of lowering the resistance of a coating film. The invention according to claim 5 uses a thermoplastic resin as the dispersion resin,
An object of the present invention is to provide a paste composition for forming a solid electrolyte capable of improving the strength of a coating film and forming a stable coating film. Claim 6
According to the invention described in claim 5, in addition to the invention described in claim 5, by using a resin having a glass transition temperature of 140 to 260 ° C. as the dispersion resin, it is possible to form a heat-resistant and thermally stable coating film. It is intended to provide a paste composition for forming a solid electrolyte. The invention according to claim 7 provides a method for manufacturing a solid electrolytic capacitor using the paste composition for forming a solid electrolyte according to any one of claims 1 to 6.

Claims (7)

[Claims] 1. A paste composition for forming a solid electrolyte comprising (A) manganese dioxide powder, (B) a dispersed resin and (C) an organic solvent as essential components. 2. The paste composition for forming a solid electrolyte according to claim 1, wherein manganese dioxide powder treated with a coupling agent such as silane, titanate, aluminum or zirconium is used. 3. The manganese dioxide powder has an average particle size of 0.0
The paste composition for forming a solid electrolyte according to claim 1, which has a thickness of 1 to 10 m. 4. The paste composition for forming a solid electrolyte according to claim 1, wherein the manganese dioxide powder has a β-type crystal structure. 5. The method according to claim 1, wherein the dispersion resin is a thermoplastic resin.
The paste composition for forming a solid electrolyte according to any one of claims 1 to 4. 6. A thermoplastic resin having a glass transition temperature of 140.
The paste composition for forming a solid electrolyte according to any one of claims 1 to 5, wherein the paste composition has a temperature of from -260 ° C. 7. A method for producing a solid electrolytic capacitor using the paste composition for forming a solid electrolyte according to any one of claims 1 to 6.