JP2000090732A - Conductive composition, and manufacture of capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide conjugated double bond conductive composition whose electric conductivity is adjusted in a large range containing thiophene derivative as a repeating unit, and a capacitor whose voltage proof characteristic, and heat and moisture resistances are good. SOLUTION: In this conductive composition and this manufacturing method for a capacitor, solution in which mixing ratio of monomer with oxidant is varied is used, solvent vaporization and polymerization are simultaneously performed, and thereby the conductive composition in which electric conductivity is adjusted according to the mixing ratio and environment stability is high is provided. By using this conductive composition as a conductive layer of the capacitor, the capacitor whose voltage proof characteristic is improved and reliability is good can be easily realized. In addition, by adding phenol derivative or nitrobenzene derivative, adjustable electric conductivity level is improved, and a capacitor characteristic is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a conductive composition, and particularly to a poly (3,4-alkylenedioxythiophene) skeleton having excellent environmental stability and a wide range of electric conductivity. The present invention relates to a method for producing a tunable conductive composition.

[0002] The present invention also relates to a manufacturing method for easily realizing a capacitor having excellent withstand voltage and high environmental stability by forming the above-mentioned conductive composition on at least one surface of a dielectric layer. .

[0003]

2. Description of the Related Art Generally, conjugated double bond conductive polymers represented by polyaniline, polypyrrole and polythiophene can be produced by chemical oxidation polymerization and electrolytic polymerization.

[0004] When electrolytic polymerization is used, it is difficult to mass-produce the conductive polymer because the conductive polymer is formed in a film on the electrode. On the other hand, when chemical oxidation polymerization is used. There is no such restriction, and a large amount of conductive polymer can be obtained relatively easily by the reaction between a polymerizable monomer and an appropriate oxidizing agent in principle.

[0005] In such a conductive polymer, it is important to impart high environmental stability and arbitrarily control electric conductivity in consideration of practical applications.

Attempts have been made to improve environmental stability by selecting a dopant or introducing an appropriate substituent into a polymerizable monomer.

In particular, studies have been actively conducted to obtain a conductive composition having high environmental stability by using, as a monomer, a thiophene having an ethylenedioxy group introduced at the β and β ′ positions (positions 3 and 4). It has been done.

Further, in recent years, studies have been actively conducted to apply the conductive composition as a solid electrolyte of an electrolytic capacitor and an electrode of a film capacitor.

[0009] At this time, particularly in a solid electrolytic capacitor, it is desired that the conductive composition can impart a high withstand voltage.

[0010]

However, it has been difficult to impart sufficiently high environmental stability, particularly high heat resistance in air, to chemically polymerized polypyrrole (PPy) unless the dopant is optimized.

In the case of poly (3,4-ethylenedioxythiophene) (PEDOT), a β-position that is easily attacked is blocked with a substituent, so that a conductive composition having high environmental stability can be easily obtained.

Furthermore, it is not possible to control only the electric conductivity over a wide range while maintaining high environmental stability by the conventionally known conductive composition preparation technology.

For example, in the case of poly (N-methylpyrrole), it is possible to lower the electric conductivity, but it has been difficult to provide practically usable environmental stability.

In the case of using PPy, the electrical conductivity can be controlled by selecting the dopant or controlling the doping ratio. However, the environmental stability often changes greatly with the control, and practical use is not practical. There was a problem that was not.

In particular, as a solid electrolyte of an electrolytic capacitor,
Although much research has been done on using these conductive compositions, it has been pointed out that the withstand voltage of such capacitors depends on the electrical conductivity of the used conductive composition. (For example, New Capacitor, Vol. 3 (No.
3), pp. 55-63, 1996) There is a strong demand to use a conductive composition capable of maintaining a high withstand voltage as an electrolyte mainly from the viewpoint of improving reliability.

For this reason, it is necessary to lower the electric conductivity of the conductive composition. However, by doing so, the environmental stability is often lowered at the same time, and as a result, a conductive material having high withstand voltage and high heat resistance is obtained. However, there is a problem that a capacitor using the conductive composition cannot be obtained.

The present invention solves the above-mentioned problems of the prior art, and comprises a conductive material containing a conjugated double bond conductive polymer capable of controlling electric conductivity over a wide range while maintaining a high level of environmental stability. It is intended to provide a method for producing the composition.

Another object of the present invention is to provide a manufacturing method for easily obtaining a solid electrolytic capacitor having high withstand voltage and excellent heat resistance and moisture resistance by utilizing the features of the conductive polymer. I do.

[0019]

SUMMARY OF THE INVENTION The present invention solves the problems of the above-mentioned prior art conductive composition and a capacitor using the conductive composition, and comprises 3,4-ethylenedioxythiophene ( In producing a conductive composition by chemical polymerization in a solvent in which EDOT) and an oxidizing agent are dissolved, the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization of the solvent and the monomer and the polymerization reaction proceed simultaneously. The method is based on a method for producing a conductive composition in which the electric conductivity of the conductive composition is adjusted.

According to this method, the phenomenon was first discovered by the present inventors and was not observed in solution polymerization in which the solvent does not substantially evaporate during polymerization.

According to this production method, a conductive composition having excellent environmental stability and having a wide range of controlled electric conductivity was realized.

This is different from the method of controlling the electric conductivity by selecting the dopant or adjusting the doping ratio which has been attempted in the past. The electric conductivity is controlled within a high range while maintaining high environmental stability. Can be controlled.

FIG. 1 shows the relationship between the electric conductivity and the yield of a conductive composition obtained by using 0.01 mol of ferric p-toluenesulfonate and changing the EDOT molar ratio to be added.

By adding EDOT in excess of the stoichiometric amount, the electric conductivity of the obtained conductive composition can be controlled depending on the amount, as shown in FIG.

FIG. 2 shows the environmental stability of the obtained conductive composition. Fig. 2 shows PP with high environmental stability.
Although the example of y was also shown, it turns out that all the conductive compositions according to the present invention have higher environmental stability.

FIG. 1 shows the yield of the conductive composition obtained using a certain amount of the oxidizing agent. From the change, as the amount of EDOT relative to the oxidizing agent increases, the degree of polymerization becomes lower, so to speak. It is conceivable that a conductive composition which may be called an oligomer is formed. An oligomer having a smaller number of repeating units, that is, an oligomer having a shorter conjugate length has a lower electric conductivity, but the environmental stability does not depend on the conjugate length. This is why the characteristic conductive composition as in the present invention can be obtained. Can be seen.

It is essential for the polymerization reaction to proceed simultaneously with the evaporation of the solvent, as described above, in order to bring out the effects of the present invention.
No such effect is seen.

Alcohols are suitable as a polymerization medium for EDOT, and among them, ethanol is considered to be optimal from the viewpoint of cost and occupational health.

In the present invention, a transition metal salt, in particular, a ferric sulfonic acid salt is preferably used, but other transition metals such as a cupric salt and a molybdenum (VI) salt can also be used. .

Further, as the anionic acid, a large degree of dissociation of a salt can be expected, and a sulfonic acid which is hard to be undoped as a dopant is particularly preferred because a sulfonic acid having an aromatic ring has a bulky molecular structure. In this case, undoping is difficult, which is preferable.

Further, when other 3,4-alkylenedioxythiophenes are used in addition to EDOT as the polymerizable monomer, the same effects can be obtained for the reasons described above.

The present invention also provides a method for producing a conductive composition by chemical polymerization in a solvent in which 3,4-ethylenedioxythiophene (EDOT), an oxidizing agent and an additive comprising a phenol derivative or a nitrobenzene derivative are dissolved. The present invention relates to a method for producing a conductive composition in which the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization and polymerization reaction of the solvent and the monomer proceed simultaneously to adjust the electric conductivity of the conductive composition.

By polymerizing in the coexistence system of the above-mentioned additives, the electric conductivity is controlled over a wide range without lowering the environmental stability, and the electric conductivity is higher than that in the case where no additive is added. It was recognized that it became higher in all areas.

Although the reason for this is not clear, it was first discovered by the inventors, and the electron-withdrawing substituent contained in the additive exerts some action during the polymerization reaction, resulting in an increase in electric conductivity. It is thought to be.

The present invention further solves the above-mentioned problem of the capacitor according to the prior art, and provides a method of manufacturing a capacitor in which the above-mentioned conductive composition is provided on at least one of the capacitor electrodes provided to face each other. Basic.

Since the conductive composition used has high environmental stability, a capacitor having excellent reliability can be realized by forming the electrode as an electrode.

Further, in the case of a capacitor having an extremely thin dielectric, particularly an electrolytic capacitor, the withstand voltage is an electrolyte, which functions as a true electrode. It is known as mentioned in the section on the problem to be solved.

That is, in order to obtain a high withstand voltage, it is desired to reduce the electric conductivity.
In the case of the above-mentioned conductive composition having a conjugated double bond, since the electric conductivity can be controlled without deteriorating the environmental stability, a solid electrolytic capacitor having a high withstand voltage is realized using the conductive composition. did it.

Further, by adding an additive comprising a phenol derivative or a nitrobenzene derivative, the electric conductivity of the obtained conductive composition is increased, so that the loss coefficient of the capacitor is reduced as compared with the case where no additive is added. did it.

Although the mechanism of the effects of the above-mentioned additives is not clear, it is considered that they exert some influence in the polymerization process and improve the electric conductivity of the obtained conductive composition.

Also, in a film capacitor in which a polymer thin film is formed as a dielectric instead of an oxide film of a valve metal, the withstand voltage of the capacitor is changed by changing the electric conductivity of the conductive composition used as an electrode. I was able to.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION
When producing a conductive composition by chemical polymerization in a solvent in which EDOT and an oxidizing agent are dissolved, changing the mixing ratio of the monomer and the oxidizing agent and simultaneously proceeding the volatilization of the solvent and the monomer and the polymerization reaction. This is a method for producing a conductive composition in which the electric conductivity of the conductive composition is adjusted by the method.

Here, as described in claim 2, a transition metal sulfonate can be used as the oxidizing agent. Further, as described in claim 3, trivalent iron is suitably used as the transition metal.

As the solvent, an alcohol solvent can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

The invention according to claim 6 of the present invention provides an EDOT
When producing a conductive composition by chemical polymerization in a solvent in which a phenol derivative is dissolved with an oxidizing agent, the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization and polymerization reaction of the solvent and the monomer proceed simultaneously. This is a method for producing a conductive composition in which the electric conductivity of the conductive composition is adjusted by causing the composition to be adjusted.

Here, a transition metal sulfonate may be used as the oxidizing agent. As described in claim 8, trivalent iron is preferably used as the transition metal.

As the solvent, an alcohol solvent can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

Here, the phenol derivative includes:
Those having an electron-withdrawing substituent are desirable, and as described in claim 11, nitrobenzene, cyanophenol, nitrobenzoic acid, and hydroxyphenol can be used.

According to a twelfth aspect of the present invention, an EDO
When producing a conductive composition by chemical polymerization in a solvent in which T, an oxidizing agent and nitrobenzene or a nitrobenzene derivative are dissolved, the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization and polymerization reaction of the solvent and the monomer Are conducted simultaneously to adjust the electrical conductivity of the conductive composition.

Here, a transition metal sulfonate can be used as the oxidizing agent. Further, as described in claim 14, trivalent iron is suitably used as the transition metal.

As the solvent, as described in claim 15,
Alcohol solvents can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

As the nitrobenzene derivative, nitrobenzoic acid and nitrobenzyl alcohol can be used.

The invention according to claim 18 of the present invention is characterized in that a step of preparing a dielectric layer, a step of preparing a solution in which a 3,4-alkylenedioxythiophene monomer and a transition metal salt oxidizing agent are dissolved, In a method for manufacturing a capacitor having a step of forming a conductive layer made of a conductive composition on at least one of the body layers, the mixing ratio of the monomer and the oxidizing agent is changed, and the evaporation and polymerization of the solvent and the monomer are performed. This is a method of manufacturing a capacitor in which the withstand voltage of the capacitor is adjusted by simultaneously proceeding the reactions.

Here, an oxide of a valve metal can be used as the dielectric layer. Here, as described in claim 20, aluminum or tantalum is preferably used as the valve metal.

Here, a polymer foil film can be used as the dielectric. Further, the polymer foil film can be formed of polyimide. Here, a transition metal sulfonate can be used as the oxidizing agent.

As described in claim 24, trivalent iron is preferably used as the transition metal. As the solvent, an alcohol-based solvent can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

According to a twenty-seventh aspect of the present invention, a step of preparing a dielectric layer, a step of preparing a solution in which EDOT, an oxidizing agent and a phenol derivative are dissolved, and a step of preparing at least one of the dielectric layers In a method for manufacturing a capacitor having a step of forming a conductive layer made of a conductive composition, a capacitor is formed by changing a compounding ratio of the monomer and the oxidizing agent and simultaneously proceeding volatilization and polymerization of the solvent and the monomer. This is a method for manufacturing a capacitor for adjusting the withstand voltage of the capacitor.

Here, an oxide of a valve metal can be used as the dielectric layer. Here, as described in claim 29, aluminum or tantalum is suitably used as the valve metal.

Here, a polymer foil film can be used as the dielectric. Further, in this case, the polymer foil film can be formed of polyimide. Here, a transition metal sulfonate can be used as the oxidizing agent.

Further, as described in claim 33, trivalent iron is preferably used as the transition metal. As a solvent, an alcohol solvent can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

Here, the phenol derivative includes:
Those having an electron-withdrawing substituent are desirable, and as described in claim 36, nitrobenzene, cyanophenol, nitrobenzoic acid, and hydroxyphenol can be used.

According to a thirty-seventh aspect of the present invention, a step of preparing a dielectric layer, a step of preparing a solution in which EDOT, an oxidizing agent and nitrobenzene or a nitrobenzene derivative are dissolved, On the other hand, in a method for manufacturing a capacitor having a step of forming a conductive layer made of a conductive composition, the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization and polymerization reaction of the solvent and the monomer proceed simultaneously. This is a method for manufacturing a capacitor in which the withstand voltage of the capacitor is adjusted by the following method.

Here, an oxide of a valve metal can be used as the dielectric layer. Here, as described in claim 39, aluminum or tantalum is suitably used as the valve metal.

Here, a polymer foil film may be used as the dielectric. Further, the polymer foil film can be formed of polyimide. Here, a transition metal sulfonate may be used as the oxidizing agent.

As described in claim 43, trivalent iron is suitably used as the transition metal. As the solvent, an alcohol-based solvent can be used.

Here, as the anion constituting the oxidizing agent, an anion containing a sulfonate ion having an aromatic ring is used.

Here, nitrobenzoic acid and nitrobenzyl alcohol can be used as the nitrobenzene derivative.

(Embodiment 1) First, a first embodiment of the present invention will be described with reference to FIGS.

First, in the present embodiment, 0.01 mol of ferric p-toluenesulfonate (FepTS) is dissolved in 6 g of ethanol, and EDOT is further dissolved in 0.005 mol, 0.01 mol, and 0.1 mol. Polymerization solutions were prepared by adding 02 mol and 0.03 mol, respectively.

Next, these solutions were placed in an evaporating dish,
This is placed in a hot air dryer controlled at 45 ° C. for 20 minutes.
The mixture was left to stand for a while to polymerize while evaporating the solvent and EDOT.

The obtained precipitate was separated by filtration, washed with ethanol, and further purified by using a Soxhlet extractor and acetone.
Time extraction was performed.

Thereafter, the resultant was dried under reduced pressure at about 40 ° C. for several hours to obtain a conductive composition. Then, after measuring the yield of the conductive composition, a part thereof was pulverized in a mortar to produce a disc-shaped pellet having a diameter of 13 mm at a pressure of about 30 MP.
It was used for measurement of electric conductivity.

The electric conductivity was measured by using a resistivity meter Loresta SP, MCP-T400 manufactured by Mitsubishi Yuka Corporation.
Was used.

FIG. 1 shows the relationship between the molar ratio of the obtained EDOT to the oxidizing agent and the initial electrical conductivity of the conductive composition.

FIG. 2 and FIG. 6 show changes over time in electrical conductivity of the obtained conductive composition in air at 125 ° C. and in 85 ° C./85% RH.

From these figures, it can be seen that the electrical conductivity of the conductive composition obtained in this example decreases depending on the ratio of the EDOT to the oxidizing agent by increasing the ratio of the oxidizing agent to the oxidizing agent. It is clear that the stability is kept relatively high.

For comparison, when polymerization (solution polymerization) was carried out under the same conditions except that a closed vessel was used, the yield of the obtained conductive composition was lower than that of the present invention in each case. The electrical conductivity was also very low.

It has been clarified that the effects of the present invention can be obtained by polymerization while evaporating the solvent.

According to the present invention, FepTS is used as the oxidizing agent, the mixing ratio of EDOT is changed, and the solvent and EDOTS are used.
It has been clarified that by conducting polymerization while evaporating T, a conductive composition having high environmental stability and a controlled electric conductivity over a wide range can be obtained in high yield.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to the drawings.

In this embodiment, a conductive composition was prepared in the same manner except that ferric dinaphthalenesulfonate (FeNS) was used in place of the FepTS used in the first embodiment, and the same evaluation was performed. went.

Also in this embodiment, as shown in FIG.
The same tendency of change in the electrical conductivity as in the first embodiment was observed due to the change in the mixing ratio of the OT to the oxidizing agent.

However, it can be seen from FIG. 3 that the variation width is even larger than when FepTS is used as the oxidizing agent.

In solution polymerization using FeNS, ED
Regardless of the mixing ratio of OT, only a conductive composition having an extremely low electric conductivity of 10-2 S / cm was obtained.

The environmental stability of the electric conductivity was also superior to PPy in any case, as in the case of the first embodiment.

According to the present invention, FeNS is used as the oxidizing agent, the mixing ratio of EDOT is changed, and the solvent and EDO are used.
It has been clarified that by conducting polymerization while evaporating T, a conductive composition having high environmental stability and a controlled electric conductivity over a wide range can be obtained in high yield.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to the drawings.

In the present example, the EDOT oxidizing agent was reduced in the same manner as in Example 1 except that 0.005 mol of p-nitrophenol (pNPh) was further added to the important solution used in Example 1. A conductive composition was prepared by changing the amount of addition, and the same evaluation as in Embodiment 1 was performed.

Also in this embodiment, as shown in FIG.
A change in electrical conductivity depending on the mixing ratio of OT to the oxidizing agent was observed.

However, the electric conductivity is pNPh in all regions.
It is clear from the comparison with FIG. 1 that it is higher than the case without addition.

The environmental stability was shown to be in a substantially same change zone as in the case where pNPh was not added, and was found to be higher than that of PPy.

According to the present invention, FepTS is used as an oxidizing agent, and pNPh is used as an additive. The mixing ratio of EDOT is changed, and the solvent and EDOT are polymerized while being volatilized. It has been found that a conductive composition having a high electric conductivity controlled over a wide range can be obtained in a high yield.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described.

In this embodiment, instead of pNPh,
(A) p-cyanophenol, (B) m-hydroxyphenol, and (C) m-hydroxybenzoic acid were each added in an amount of 0.05 mol, in the same manner as in Embodiment 1, except that the amount of EDOT added to the oxidizing agent was changed. A conductive composition was produced by changing the same, and the same evaluation as in the first embodiment was performed.

In the present embodiment, almost the same change in the electric conductivity as in the first embodiment was observed due to the change in the mixing ratio of EDOT to the oxidizing agent.

Incidentally, the electric conductivity is 22 in the case of (A).
From S / cm to 0.016 S / cm, (B) 2
It changed from 0.2 S / cm to 0.015 S / cm, and in the case of (C), it changed from 19 S / cm to 0.013 S / cm.

Further, with respect to the environmental stability, it exhibited almost the same change behavior as when no additive was used, and it was clarified that it was superior to PPy.

According to the present invention, EDOT is used by using FepTS as an oxidizing agent and a phenol derivative as an additive.
It is apparent that by changing the compounding ratio of the above and polymerizing while evaporating the solvent and EDOT, a conductive composition having a controlled electric conductivity over a high range can be obtained in high yield.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described.

In this embodiment, instead of pNPh,
(A) nitrobenzene, (B) m-nitrobenzoic acid,
(C) p-nitrobenzyl alcohol in 0.05
EDO was carried out in the same manner as in Embodiment 1 except that mol was added.
A conductive composition was prepared by changing the amount of T added to the oxidizing agent, and the same evaluation as in Embodiment 1 was performed.

In the present embodiment, almost the same change in electric conductivity as in the first embodiment was observed due to the change in the mixing ratio of EDOT to the oxidizing agent.

Incidentally, the electric conductivity is 24 in the case of (A).
From S / cm to 0.017 S / cm, (B) 1
It changed from 9 S / cm to 0.011 S / cm, and in the case of (C), it changed from 21 S / cm to 0.014 S / cm.

The environmental stability of the conductive composition according to the present embodiment is almost the same as that of the conductive composition of the first embodiment, and is higher than PPy.
According to the present invention, electric conductivity is controlled over a wide range by using FepTS as an oxidizing agent and nitrobenzene and its derivatives as additives, changing the blending ratio of EDOT, and polymerizing while evaporating the solvent and EDOT. It has been clarified that the obtained conductive composition can be obtained in high yield.

(Embodiment 6) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a sectional view of a capacitor showing an embodiment of the present invention. To partition the 4 × 10 mm2 aluminum etched foil 1 into 3 mm and 6 mm parts,
A polyimide tape 2 having a width of 1 mm is stuck on both sides.

Next, an aluminum-etched foil of 4 × 3 m
The anode lead 3 is attached to the portion m, and a 4 × 6 mm portion of the aluminum-etched foil is applied with a 3% ammonium adipate aqueous solution at about 70 ° C. at 50 V to form an oxide film dielectric layer 4 by anodic oxidation. did.

This structure was regarded as a capacitor, and the capacity in a chemical conversion solution was 4.7 μF.

Further, using this structure, FepTS was 1.6 M, EDOT was a molar ratio of (A) 1: 0.5,
The conductive composition layer is immersed in an ethanol solution changed so as to contain (B) 1: 1, (C) 1: 2, and (D) 1: 3, and then polymerized while evaporating the solvent in the air. 5 was formed.

This treatment was repeated until the aluminum-etched foil was completely covered with the conductive composition.

On the etched aluminum foil on which the conductive composition was formed, a cathode was formed with a carbon layer 6 and a silver paint layer 7, and a cathode lead 8 was attached thereon, so that a total of 20 capacitor elements were formed. Obtained.

Further, the device was packaged with epoxy resin 9 and subjected to an aging treatment at 13 ° C. at a voltage of 13 V to complete the capacitor.

For these 20 elements, 120 kHz
The capacitance and the loss coefficient at z were measured, and the withstand voltage was measured for each of 10 samples.

Further, using 5 pieces each at 125 ° C.
A 1000-hour no-load life test was performed in air and at 85 ° C./85%, and the capacity change rate and the loss coefficient were measured.

The average values are shown in (Table 1).

[0120]

[Table 1]

As is clear from Table 1, according to the present embodiment, it is found that a capacitor with improved withstand voltage can be obtained by increasing the ratio of EDOT added to FepTS.

It is also clear that even in this case, deterioration of the environmental stability of the capacitor is hardly observed.
(Embodiment 7) The capacitor manufactured according to the present invention was proved to have excellent characteristics. (Embodiment 7) The following tantalum sintered body electrode was used in place of the aluminum foil electrode of Embodiment 6, Ten capacitors were completed under the same conditions as in the second embodiment, and the characteristics were evaluated in the same manner as in the embodiment. The results are shown in (Table 1).

A specific method for producing a tantalum sintered body electrode is as follows. First, a 2 × 1.4 × 0.9 mm tantalum sintered body was used in a solution in which 5 ml of phosphoric acid was dissolved in 1000 ml of water, and a voltage of 40 V was applied at about 90 ° C. to form an oxide film dielectric layer by anodic oxidation. .

This structure was regarded as a capacitor, and the capacity in a chemical conversion solution was measured to be 17.0 μF.

Using this structure, 20 capacitor elements were completed in the same manner as in the sixth embodiment.

As is clear from Table 1, according to the present embodiment, it is found that a capacitor with improved withstand voltage can be obtained by increasing the ratio of EDOT added to FepTS.

It is also clear that even in this case, deterioration of the environmental stability of the capacitor is hardly observed.
(Embodiment 8) A capacitor manufactured according to the present invention was proved to have excellent characteristics. (Embodiment 8) A 20 mm × 20 mm aluminum smooth foil on which a dielectric film was formed under the same conditions as in Embodiment 6 was used. Instead of forming an oxide film dielectric as in the above, except using an electrode on which a polyimide dielectric layer composed of a polyimide thin film was formed by spin coating,
Under substantially the same conditions as in the second embodiment, a total of 20 capacitors were manufactured.

The same evaluation as in Embodiment 6 was performed for these. The results are shown in (Table 1).

As is clear from Table 1, according to the present embodiment, it is found that a capacitor with improved withstand voltage can be obtained by increasing the addition ratio of EDOT to FepTS.

It is also clear that even in such a case, deterioration of the environmental stability of the capacitor is hardly observed.
It was proved that the capacitor manufactured according to the present invention had excellent characteristics. (Embodiment 9)
Ferric 2-naphthalene sulfonate (FeN)
Except for using S), a total of 20 capacitors were manufactured under substantially the same conditions as in the sixth embodiment.

The same evaluation as in the sixth embodiment was performed for these. The average values are shown in (Table 1).

As is clear from Table 1, according to the present embodiment, it is found that a capacitor with improved withstand voltage can be obtained by increasing the ratio of EDOT to FeNS.

It is also clear that even in this case, deterioration of the environmental stability of the capacitor is hardly observed.
The capacitors made according to the present invention have proven to have excellent properties.

(Embodiment 10) In the configuration of Embodiment 6, the same characteristic evaluation as in Embodiment 6 was conducted except that 0.8 M of pNPh was further added, and substantially the same as in Embodiment 6. Under the conditions, 20 capacitors were produced respectively.

The same evaluation as in Embodiment 6 was performed for these. The average values are shown in (Table 1).

As is apparent from Table 1, according to the present embodiment, it is found that a capacitor with improved withstand voltage can be obtained by increasing the ratio of EDOT added to FepTS.

In addition, the effect of the addition of pNPh improves the electrical conductivity of the conductive composition layer, so that the loss coefficient can be reduced as compared with the case where no addition is made.

(Embodiment 11) In the structure of Embodiment 10, the molar ratio between EDOT and FepTS is fixed to 1: 2, and (A) p-cyanophenol is used instead of pNPh.
Twenty capacitors were produced under substantially the same conditions as in Embodiment 6 except that (B) m-hydroxyphenol and (C) m-hydroxybenzoic acid were used.

The same evaluation as in the sixth embodiment was performed for these. The same characteristic evaluation as in the sixth embodiment was performed, and the average values thereof are shown in (Table 1).

As is clear from Table 1, according to the present embodiment, it can be seen that the same effect as in the case of pNPh can be obtained by adding various phenol derivatives having an electron-withdrawing substituent.

(Twelfth Embodiment) In the structure of the tenth embodiment, the molar ratio between EDOT and FepTS is fixed at 1: 2, and (A) nitrobenzene and (B) m are used instead of pNPh.
A total of 20 capacitors were manufactured under substantially the same conditions as in Embodiment 6, except that -nitrobenzoic acid and (C) p-nitrobenzyl alcohol were used.

The same evaluation as in the sixth embodiment was performed for these. The average values are shown in (Table 1).

As is clear from Table 1, according to the present embodiment, it can be seen that the same effect as in the case of pNPh can be obtained by adding nitrobenzene and its derivatives. In the embodiment, only the case where ethanol is used as the solvent has been described. However, other alcohols such as methanol and propanol may be used, and the present invention does not depend on these alcohols.

[0144]

According to the constitution of the present invention, it is possible to efficiently produce a highly environmentally stable conductive composition having a controlled electric conductivity over a wide range.

Further, the withstand voltage of the capacitor can be improved by forming the conductive polymer obtained in the present invention on the surface of the dielectric film. That is, the withstand voltage can be increased by lowering the electric conductivity of the conductive composition to be formed, and even in such a case, the environment stability of the conductive composition is maintained at a high level. Capacitors with excellent moisture resistance can be realized.

Further, by adding a phenol derivative, nitrobenzene or a derivative thereof, the electric conductivity of the obtained conductive composition is improved, so that a capacitor having a small loss coefficient can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a molar ratio of ethylenedioxythiophene / oxidizing agent and electric conductivity of an obtained conductive composition in Embodiment 1 of the present invention.

FIG. 2 is a diagram showing the relationship between the ethylene dioxythiophene / oxidizing agent molar ratio and the environmental stability of the obtained conductive composition in Embodiment 1, including comparison with polypyrrole.

FIG. 3 is a diagram showing the relationship between the molar ratio of ethylenedioxythiophene / oxidizing agent and the electrical conductivity of the obtained conductive composition in Embodiment 2.

FIG. 4 is a diagram showing a relationship between a molar ratio of ethylenedioxythiophene / oxidizing agent and electric conductivity of the obtained conductive composition in Embodiment 3.

FIG. 5 is a diagram showing one embodiment of a capacitor according to a sixth embodiment.

FIG. 6 is a diagram showing the relationship between the ethylene dioxythiophene / oxidizing agent molar ratio and the environmental stability of the obtained conductive composition in Embodiment 1, including a comparison with polypyrrole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum-etched foil 2 Polyimide tape 3 Anode lead 4 Anodized film 5 Conductive composition conductive layer 6 Carbon layer 7 Silver paint layer 8 Cathode lead 9 Epoxy resin outer layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasue Matsuya 3-10-1 Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa F-term in Matsushita Giken Co., Ltd. 4J032 BA04 BB01 BC03 BC13 CE03 CE16 CE24 CG01

Claims (46)

[Claims] 1. A solution in which 3,4-ethylenedioxythiophene and an oxidizing agent are dissolved, the mixing ratio of the monomer and the oxidizing agent is changed, and the volatilization of the solvent and the monomer and the polymerization reaction are simultaneously advanced. A method for producing a conductive composition, wherein the electric conductivity of the conductive composition is adjusted by the method. 2. The method for producing a conductive composition according to claim 1, wherein the oxidizing agent is a transition metal sulfonate. 3. The method for producing a conductive composition according to claim 1, wherein the transition metal is trivalent iron. 4. The method according to claim 1, wherein the solvent is an alcohol solvent.
4. The method for producing a conductive composition according to items 3 to 3. 5. The production method according to claim 1, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 6. A solution in which a 3,4-ethylenedioxythiophene monomer, an oxidizing agent and a phenol derivative are dissolved, a mixing ratio of the monomer and the oxidizing agent is changed, and a volatilization and polymerization reaction of the solvent and the monomer are performed. A method for producing a conductive composition in which the electric conductivity of the conductive composition is adjusted by simultaneously proceeding the steps. 7. The method for producing a conductive composition according to claim 6, wherein the oxidizing agent is a transition metal sulfonate. 8. The method for producing a conductive composition according to claim 6, wherein the transition metal is trivalent iron. 9. The solvent according to claim 6, wherein the solvent is an alcohol solvent.
9. The conductive composition according to any one of items 1 to 8. 10. The production method according to claim 6, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 11. The method for producing a conductive composition according to claim 6, wherein the phenol derivative is nitrophenol, cyanophenol, nitrobenzoic acid, or hydroxyphenol. 12. A solution in which a 3,4-alkylenedioxythiophene monomer, an oxidizing agent and nitrobenzene or a nitrobenzene derivative are dissolved, wherein the mixing ratio of the monomer and the oxidizing agent is changed, and the solvent and the volatilization of the monomer are changed. A method for producing a conductive composition, wherein the electric conductivity of the conductive composition is adjusted by simultaneously proceeding the polymerization reaction. 13. The method for producing a conductive composition according to claim 12, wherein the oxidizing agent is a transition metal sulfonate. 14. The transition metal according to claim 12, wherein the transition metal is trivalent iron.
Or a method for producing a conductive composition according to item 13. 15. The conductive composition according to claim 12, wherein the solvent is an alcohol-based solvent. 16. The method according to claim 12, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 17. The method for producing a conductive composition according to claim 12, wherein the nitrobenzene derivative is nitrobenzene, nitrobenzoic acid, or nitrobenzyl alcohol. 18. A step of preparing a dielectric layer, a step of preparing a solution in which a 3,4-alkylenedioxythiophene monomer and a transition metal salt oxidizing agent are dissolved, and forming a conductive layer in at least one of the dielectric layers. In a method for producing a capacitor having a step of forming a conductive layer made of a conductive composition, a method of producing a capacitor by changing the mixing ratio of the monomer and the oxidizing agent and simultaneously proceeding the volatilization and polymerization reaction of the solvent and the monomer. A method for manufacturing a capacitor that controls the withstand voltage. 19. The method according to claim 18, wherein the dielectric layer is an oxide of a valve metal. 20. The method according to claim 18, wherein the valve metal is aluminum or tantalum. 21. The method according to claim 1, wherein the dielectric layer is a polymer film.
9. The method for manufacturing a capacitor according to item 8. 22. The method according to claim 21, wherein the polymer film is a polyimide film. 23. The method for producing a conductive composition according to claim 18, wherein the oxidizing agent is a transition metal sulfonate. 24. The transition metal according to claim 18, wherein the transition metal is trivalent iron.
24. The method for producing a conductive composition according to any one of items 23 to 23. 25. The method for producing a conductive composition according to claim 18, wherein the solvent is an alcohol-based solvent. 26. The method according to claim 18, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 27. A step of preparing a dielectric layer; a step of preparing a solution in which a 3,4-ethylenedioxythiophene monomer, an oxidizing agent and a phenol derivative are dissolved; In a method for manufacturing a capacitor having a step of forming a conductive layer made of a conductive composition,
A method of manufacturing a capacitor, wherein the withstand voltage of a capacitor is adjusted by changing the mixing ratio of the monomer and the oxidizing agent and simultaneously proceeding the vaporization and polymerization of the solvent and the monomer. 28. The method according to claim 27, wherein the dielectric layer is an oxide of a valve metal. 29. The method according to claim 27, wherein the valve metal is aluminum or tantalum. 30. The dielectric layer according to claim 2, wherein the dielectric layer is a polymer film.
8. The method for manufacturing a capacitor according to 7. 31. The method according to claim 30, wherein the polymer film is a polyimide film. 32. The method according to claim 27, wherein the oxidizing agent is a transition metal sulfonate. 33. The transition metal of claim 27, wherein the transition metal is trivalent iron.
33. The method for producing a conductive composition according to any one of items 30 to 32. 34. The method for producing a conductive composition according to claim 27, wherein the solvent is an alcohol-based solvent. 35. The production method according to claim 27, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 36. The method according to claim 27, wherein the phenol derivative is nitrophenol, cyanophenol, hydroxybenzoic acid or hydroxyphenol. 37. A step of preparing a dielectric layer, a step of preparing a solution in which a 3,4-alkylenedioxythiophene monomer, an oxidizing agent and nitrobenzene or a nitrobenzene derivative are dissolved, and at least one of the dielectric layers. In a method for manufacturing a capacitor having a step of forming a conductive layer composed of a conductive composition, by changing the mixing ratio of the monomer and the oxidizing agent and simultaneously proceeding the volatilization and polymerization reaction of the solvent and the monomer. A method of manufacturing a capacitor that adjusts the withstand voltage of the capacitor. 38. The method according to claim 37, wherein the dielectric layer is an oxide of a valve metal. 39. The method according to claim 37, wherein the valve metal is aluminum or tantalum. 40. The dielectric layer according to claim 3, wherein the dielectric layer is a polymer film.
8. The method for manufacturing a capacitor according to 7. 41. The method according to claim 40, wherein the polymer film is a polyimide film. 42. The method for producing a conductive composition according to claim 37, wherein the oxidizing agent is a transition metal sulfonate. 43. The transition metal is trivalent iron.
43. The method for producing a conductive composition according to any one of items 44 to 42. 44. The method for producing a conductive composition according to claim 37, wherein the solvent is an alcohol-based solvent. 45. The method according to claim 37, wherein the sulfonate ion is a sulfonate ion having an aromatic ring. 46. The method for producing a conductive composition according to claim 37, wherein the nitrobenzene derivative is nitrobenzene, nitrobenzoic acid, or nitrobenzyl alcohol.