JP2006104314A - Purification method of π-conjugated conductive polymer, electric energy storage device and semiconductor device - Google Patents

Abstract

【Task】
A method for purifying π-conjugated conductive polymers with excellent heat resistance and moisture resistance that can be applied to electrical energy storage devices and semiconductor devices by efficiently removing residual iron ions in π-conjugated conductive polymers obtain.
[Solution]
A method for purifying a π-conjugated conductive polymer produced from a monomer as a raw material of a π-conjugated conductive polymer by an oxidative polymerization reaction using an aromatic sulfonic acid metal salt as an oxidizing agent, the polymerization After the reaction, the iron ions remaining in the π-conjugated conductive polymer are removed by washing with a washing liquid containing a predetermined chelate compound and controlling its concentration, solution temperature, pH and the like. Since the obtained π-conjugated conductive polymer is excellent in heat resistance and moisture resistance, it is suitable as a constituent material for electrical energy storage devices and semiconductor devices.
[Selected drawing] None

Description

  The present invention relates to a method for purifying a π-conjugated conductive polymer excellent in heat resistance and moisture resistance. More specifically, the present invention relates to the heat resistance and moisture resistance of a π-conjugated conductive polymer produced by a chemical oxidative polymerization method. The present invention relates to a purification method for improvement, and also relates to an electrical energy storage device such as a capacitor or an organic solar cell, and a semiconductor device used for a diode or electroluminescence, utilizing the light, electronic and electromagnetic characteristics of the conductive polymer.

  Various methods such as chemical oxidative polymerization, electrolytic oxidative polymerization, soluble precursor method, and vapor deposition are known as methods for producing π-conjugated conductive polymers. It is necessary to select an optimal production method depending on the type of molecule and its application.

  Among the above production methods, the chemical oxidative polymerization method has a feature that it is inexpensive and the production conditions can be easily controlled, and many π typified by polypyrrole, polyalkylenedioxythiophene, polyaniline and derivatives thereof. It is applied to the production of conjugated conductive polymers.

  These π-conjugated conductive polymers are conductive polymers having an electrical conductivity of 10 S / cm or more by chemical oxidative polymerization using an aromatic sulfonic acid metal salt such as ferric toluenesulfonate as an oxidizing agent. Since it can be easily produced, application as a solid electrolytic capacitor, a wet solar cell, a catalyst electrode for organic electrolytic synthesis, an antistatic material such as a plastic film, a gas sensor for identifying an odor, and the like has been studied.

  As an industrial application example of a π-conjugated conductive polymer, an example in which polyalkylenedioxythiophene (hereinafter abbreviated as “PADOT”) is applied to a solid electrolyte of an aluminum solid electrolytic capacitor as a charge storage device is as follows. Explained. FIG. 1 is a schematic sectional view of an aluminum solid electrolytic capacitor.

  The aluminum solid electrolytic capacitor anodizes an aluminum foil 1 which is a valve action metal in an electrolytic solution such as boric acid to form a dielectric oxide film 2. This element is immersed in an aqueous solution containing ferric toluenesulfonate and / or an organic solvent, and then immersed in an alkylenedioxythiophene monomer (hereinafter abbreviated as “ADOT”) solution, whereby a dielectric is obtained. The oxidant impregnated in the oxide film 2 and the alkylenedioxythiophene monomer are brought into contact with each other, and a PADOT layer is formed as the solid electrolyte layer 3 inside and on the surface of the oxide film. In general, since a PADOT layer having a desired thickness cannot be formed by a single operation, the cathode conductive layer 4 composed of a graphite layer and a silver paste layer is sequentially formed after the above operation is repeated a plurality of times.

  The obtained capacitor element is placed on a lead frame, the anode terminal portion 5 of the capacitor element is electrically joined to the external anode lead 6, and the cathode conductive layer 4 is connected to the external cathode lead via the conductive adhesive 7. 8 and then molded with exterior resin 9 to complete an aluminum solid electrolytic capacitor.

  In the manufacturing process of the solid electrolytic capacitor, as the oxidizing agent for forming the PADOT layer, an oxidizing agent solution containing ferric toluenesulfonate in water and / or an organic solvent is used. The ferric ion acts as an oxidant to chemically oxidize ADOT, and a counter ion, toluenesulfonic acid ion, is introduced into the PADOT layer as a dopant.

  A solid electrolytic capacitor using PADOT as a solid electrolyte has excellent high-frequency characteristics because its electric conductivity is about 100 times higher than that of manganese dioxide, which has been conventionally used as a solid electrolyte for tantalum solid electrolytic capacitors.

  Also, according to the chemical oxidative polymerization method, PADOT can be easily produced by bringing the oxidant solution and ADOT into contact with each other, compared with the electrolytic polymerization method in which the production conditions are difficult and difficult to control, and the production process is simple. And industrially advantageous.

  In general, in order to apply a π-conjugated conductive polymer as a solid electrolyte of an electrical energy storage device such as a solid electrolytic capacitor, in addition to electrical conductivity, weather resistance, particularly stability at high temperatures and high humidity, is required. Required.

  In the π-conjugated conductive polymer formed by the chemical oxidative polymerization method, iron ions remain as impurities, and the iron ions form a local battery against the metal or metal oxide such as aluminum that comes into contact. May cause corrosion and may cause cracks in the dielectric oxide film. In addition, π-conjugated conductive polymers are in a highly oxidized state doped with anions, and are subject to performance degradation due to the interaction of heat, light, oxygen, water, etc. The speed is further increased. These drawbacks are a major obstacle to using π-conjugated conductive polymers as device materials, and among PADOT having relatively high heat resistance and moisture resistance among π-conjugated conductive polymers. This is no exception.

  Various methods have been proposed to improve the heat resistance and moisture resistance of the π-conjugated conductive polymer. For example, in the method for producing a π-conjugated conductive polymer disclosed in Patent Document 1, chemical oxidative polymerization is performed in an aprotic solvent containing a compound containing at least one of an OH group or a COOH group as an oxidant dopant, and the dopant A method for preventing oxidative degradation by protons efficiently supplied from the sea has been proposed.

  In addition, the method for producing a π-conjugated conductive polymer disclosed in Patent Document 2 includes washing in a non-aqueous organic solvent such as carbonates or lactones, and unpolymerized or having a low degree of polymerization. There has been proposed a method for removing a molecule and purifying a π-conjugated conductive polymer having oxidation resistance and a high degree of polymerization.

  However, even if protons or hydrogen are supplied from the dopant by the above method or a π-conjugated conductive polymer having a high degree of polymerization is purified, iron ions taken into the π-conjugated conductive polymer are not In contact with the base metal of the capacitor element and its oxide, a local battery is formed, and the contact area with oxygen and water increases at an accelerated rate due to cracks in the π-conjugated conductive polymer caused by corrosion of the base. Therefore, there remains a problem to be solved that the heat resistance and moisture resistance of the π-conjugated conductive polymer is lowered.

JP-A-10-251384 Japanese Patent Laid-Open No. 2002-270466

  An object of the present invention is to provide a π-conjugated conductive polymer having improved heat resistance and moisture resistance by removing residual metal ions in the π-conjugated conductive polymer produced by a chemical oxidative polymerization method. It is to provide a purification method, and to provide an electrical energy storage device and a semiconductor device that are composed of the conductive polymer and are excellent in heat resistance and moisture resistance.

  As a result of intensive research on a method for purifying a π-conjugated conductive polymer, the present inventors have refined the π-conjugated conductive polymer using a specific chelate compound-containing cleaning solution, thereby achieving the above-mentioned problem. It has been found that it can be solved, and the present invention has been completed.

  That is, the present invention is a method for purifying a π-conjugated conductive polymer produced by an oxidative polymerization reaction using an aromatic sulfonic acid metal salt as an oxidizing agent from a monomer of a π-conjugated conductive polymer. The π-conjugated conductive polymer is characterized in that metal ions remaining in the π-conjugated conductive polymer are removed by washing the π-conjugated conductive polymer with a cleaning liquid containing a chelate compound. This is a method for purifying a functional polymer.

  In the present invention, the chelate compound is at least one selected from the group consisting of dipyridyl, terpyridyl, phenanthroline, diphenylthiocarbazone compound, nitrosonaphthol compound and aminopolycarboxylic acid compound. This is a method for purifying a conductive polymer.

  Furthermore, the present invention is an electrical energy storage device and a semiconductor device composed of a π-conjugated conductive polymer obtained by the above purification method.

  According to the present invention, a π-conjugated conductive polymer produced by a chemical oxidative polymerization method can be purified by a simple process, and iron ions remaining in the π-conjugated conductive polymer are effectively removed. Thus, the heat resistance and moisture resistance of the π-conjugated conductive polymer can be improved.

  In addition, an electrical energy storage device such as a solid electrolytic capacitor using a π-conjugated conductive polymer purified by the present invention, and a semiconductor device are excellent in heat resistance and moisture resistance.

  The present invention relates to a method for purifying a π-conjugated conductive polymer produced by an oxidative polymerization reaction using an aromatic sulfonic acid metal salt as an oxidizing agent from a π-conjugated conductive polymer monomer, By washing the π-conjugated conductive polymer with a cleaning liquid containing a chelate compound, metal ions remaining in the π-conjugated conductive polymer are removed.

  Examples of the monomer of the π-conjugated conductive polymer used in the present invention include pyrrole, ADOT, aniline, phenylene, acetylene, furan, phenylene vinylene, azulene, and derivatives thereof. Pyrrol, ADOT, aniline, and their derivatives are preferred because the conductive polymer is excellent in electrical conductivity and exhibits a low equivalent series resistance (ESR) in the high frequency region (1 kHz to 100 kHz) of the capacitor. Among these, pyrrole and its derivatives that can realize low ESR in a higher frequency region (100 kHz to 50 MHz) are particularly preferable. In addition, pyrrole is more effective in adapting the present invention because the reaction rate of oxidative polymerization is high and a large amount of metal ions are easily taken into the polymer.

  Examples of the aromatic sulfonic acid metal salt that is an oxidizing agent include ferric o-toluenesulfonate, ferric m-toluenesulfonate, ferric p-toluenesulfonate, cupric o-toluenesulfonate, m -Cuprous toluene sulfonate, cupric p-toluene sulfonate, cobalt o-toluene sulfonate, cobalt m-toluene sulfonate, cobalt p-toluene sulfonate, manganese o-toluene sulfonate, m-toluene sulfonic acid Examples thereof include manganese, manganese p-toluenesulfonate, ferric o-ethylbenzenesulfonate, ferric m-ethylbenzenesulfonate, ferric p-ethylbenzenesulfonate, ferric naphthalenesulfonate, and derivatives thereof.

  The aromatic sulfonic acid metal salts exemplified above are preferably ferric p-toluenesulfonate and cupric p-toluenesulfonate because they can be easily controlled and industrially inexpensively obtained.

  In the present invention, the π-conjugated conductive polymer to be purified is produced by a conventionally known method by an oxidative polymerization reaction between a monomer of a π-conjugated conductive polymer and an aromatic sulfonic acid metal salt. Can do. Specifically, in an organic solvent such as ethanol, 1 to 4 times (molar ratio) of an aromatic sulfonic acid metal salt is added to the monomer of the π-conjugated conductive polymer that is the starting material. The π-conjugated conductive polymer can be generated by reacting for several tens of minutes to several hours. The obtained π-conjugated conductive polymer is washed with a solvent such as pure water or ethanol, and then metal ions remaining in the polymer are removed by the purification method of the present invention described below.

  The cleaning liquid used in the present invention comprises at least a solution of water and / or an organic solvent containing a chelate compound, and by using the cleaning liquid containing the compound, residual metal ions in the π-conjugated conductive polymer are effective. Can be removed.

As the chelate compound, at least one selected from the group consisting of dipyridyl, terpyridyl, phenanthroline, diphenylthiocarbazone compound, nitrosonaphthol compound and aminopolycarboxylic acid compound is used. Removal of iron ions (Fe ²⁺ ) in order to easily form complex ions of a chelate compound and efficiently remove divalent iron ions (Fe ²⁺ ) and trivalent iron ions (Fe ³⁺ ) It is preferable to use in combination at least one selected from the group consisting of dipyridyl, terpyridyl, and phenanthroline, which are excellent in effect, and a nitrosonaphthol compound, which is excellent in the effect of removing iron ions (Fe ³⁺ ).

  Examples of the diphenylthiocarbazone compound include enol-type diphenylthiocarbazone, keto-type diphenylthiocarbazone, and derivatives thereof.

  Examples of the nitrosonaphthol compound include 2-nitroso-1-naphthol, 1-nitroso-2-naphthol, nitroso-R salt and derivatives thereof.

  Examples of aminopolycarboxylic acid compounds include ethylenediaminetetraacetic acid (abbreviated as “EDTA”), nitrilotriacetic acid, iminodiacetic acid, 1,2-cyclohexanediaminetetraacetic acid. (1,2-cyclohexandiaminetetraacetic acid), diethylenetriaminepentaacetic acid, ethyletherdiaminetetraacetic acid, hydroxyethylenediaminetriacetic acid (hydroxyethylenediamineacetic acid) traicic acid), N, N-bis (2-hydroxyethyl) glycine [N, N-bis (2-hydroxyethyl) glycine], anthranilic acid diacetic acid, glycol ether diaminetetraacetic acid, Examples thereof include methylglycine diacetic acid and its alkali metal salt.

  The π-conjugated conductive polymer exhibits high electrical conductivity when doped with an anion such as toluene sulfonate ion, but this anion has the electrical conductivity of the π-conjugated conductive polymer, It greatly affects the weather resistance such as heat resistance and moisture resistance. If a large amount of anionic chelate compound is present in the cleaning solution, the chelate compound is incorporated into the π-conjugated conductive polymer, which adversely affects electrical conductivity and weather resistance. The compound concentration is preferably less than 0.2 mol / L, more preferably less than 0.1 mol / L.

  During the washing operation, aromatic sulfonate ions in the π-conjugated conductive polymer may be dedoped, resulting in a decrease in electrical conductivity. When applied to a solid electrolyte of a solid electrolytic capacitor, the heat resistance and high frequency range ESR at the time is reduced. In order to prevent this undoping, the cleaning liquid preferably contains at least 0.2 mol / L of aromatic sulfonate ions, more preferably at least 0.4 mol / L.

  In addition, the cleaning liquid containing a chelate compound may corrode aluminum and its metal oxide which are valve metals of a solid electrolytic capacitor and deteriorate leakage current. To prevent this, the pH of the cleaning liquid is adjusted to 3 to 8. It is preferable to control to 4-6.

  Compounds containing aromatic sulfonate ions to be added to the cleaning liquid used in the present invention include p-toluenesulfonic acid monohydrate, tetraethylammonium-p-toluenesulfonic acid, mono-p-toluenesulfonic acid urea, p -Sodium toluene sulfonate, 2-amino-5-methylbenzene-1-sulfonic acid, 1-cyclohexyl-3- (2-morpholinoethyl) carbodiimidometh-p-toluenesulfonic acid, N-cyclohexyl-N '-(2 -Morpholinoethyl) carbodiimidometh-p-toluenesulfonic acid salt, p-toluenesulfonyl hydrazide, naphthalenesulfonic acid and derivatives thereof, and the like, and these compounds can also be used as a pH adjuster for the washing liquid.

  As the pH adjuster for the cleaning liquid used in the present invention, sulfuric acid, nitric acid, aqueous ammonia and the like are used in addition to the above-described compounds.

  The temperature of the cleaning liquid used in the present invention is preferably controlled in the temperature range of 30 to 80 ° C., more preferably 60 to 80 ° C., in order to promote the chelate formation reaction.

  As a method of cleaning the π-conjugated conductive polymer using the cleaning liquid, a conventionally known method can be used. For example, a method of immersing a π-conjugated conductive polymer in the cleaning liquid used in the present invention, or a cleaning liquid And a shower cleaning method in which is sprayed onto a π-conjugated conductive polymer. After this washing operation, washing with an appropriate solvent (for example, pure water, isopropanol or a mixed solvent thereof), and preferably washing with a solution containing aromatic sulfonate ions.

  The π-conjugated conductive polymer purified by the above process efficiently removes iron ions, yielding a π-conjugated conductive polymer with excellent heat resistance and moisture resistance, to light, electronic, and electromagnetic devices. Can be applied.

  Next, the method for purifying a π-conjugated conductive polymer of the present invention will be described in detail with reference to FIG. 1, taking an example of application to an aluminum solid electrolytic capacitor.

  The aluminum foil 1 on which the etching treatment and the dielectric oxide film 2 are formed is impregnated with an oxidizing agent solution composed of water and / or an organic solvent containing an aromatic sulfonic acid metal salt, and then immersed in an ADOT solution. A PADOT layer that is the solid electrolyte 3 is formed.

  After the foil is washed with pure water or the like, iron ions remaining in the PADOT layer are removed by a washing operation such as immersing in a washing solution containing a chelate compound. At that time, the chelate compound concentration is preferably less than 0.2 mol / L.

  As the chelate compound, as described above, at least one selected from the group consisting of aminopolycarboxylic acid compounds, dipyridyl, terpyridyl, phenanthroline, diphenylthiocarbazone compounds and nitrosonaphthol compounds can be used. It is preferable to use at least one selected from the group consisting of terpyridyl and phenanthroline in combination with a nitrosonaphthol compound.

  The cleaning liquid containing the chelate compound is preferably controlled to have a pH of 3 to 8 and contains at least 0.2 mol / L of an aromatic sulfonate ion, for example, toluene sulfonate ion. Moreover, it is preferable that this washing | cleaning liquid is controlled to the temperature of 30-80 degreeC.

  After the PADOT layer is formed on the dielectric oxide film, the operation of cleaning with the above cleaning solution is repeated once or a plurality of times to form a PADOT layer having a desired thickness, and then a cathode comprising a graphite layer and a silver paste layer Conductive layer 4 is formed to obtain a capacitor element.

  The obtained capacitor element is placed on a lead frame, the anode terminal portion 5 of the capacitor element is electrically joined to the external anode lead 6, and the cathode conductive layer 4 is connected to the external cathode lead via the conductive adhesive 7. 8 and then molded with the exterior resin 9 to complete the aluminum solid electrolytic capacitor of the present invention.

  According to the present invention, a π-conjugated conductive polymer produced by a chemical oxidative polymerization method can be purified by a simple process, and iron ions remaining in the π-conjugated conductive polymer are effectively removed. Thus, the heat resistance and moisture resistance of the π-conjugated conductive polymer can be improved.

  In addition, an electrical energy storage device such as a solid electrolytic capacitor using a π-conjugated conductive polymer purified by the present invention, and a semiconductor device are excellent in heat resistance and moisture resistance.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited at all by the Example.

Example 1
As an oxidant solution, a solution of ferric p-toluenesulfonate / butanol = 0.4 mol / 200 mL was prepared.

  Next, in FIG. 1, 3,4-ethylenedioxythiophene (hereinafter abbreviated as “EDOT”) on an etching aluminum foil 1 (6 × 4 mm) having a thickness of 200 μm on which a dielectric oxide film 2 is formed. After applying the solution and then the previously prepared oxidant solution, chemical oxidative polymerization is performed while removing the solvent in an atmosphere of 120 ° C., and the solid electrolyte 3 is abbreviated as polyethylene dioxothiophene (hereinafter “PEDOT”). ) Layer was formed.

  In the cleaning solution at a temperature of 60 ° C. adjusted to pH 5 containing 0.3 mol / L of EDTA-2Na and 0.4 mol / L of tetraethylammonium-p-toluenesulfonic acid as chelate compounds after washing the device with ethanol For 10 minutes and then washed with pure water.

  The above process was repeated until the thickness of the PEDOT layer became 15 μm, and then a cathode conductive layer 4 composed of a carbon layer and a silver paste layer was formed to produce a capacitor element.

  The obtained capacitor element was packaged to complete the aluminum solid electrolytic capacitor shown in FIG.

  For the 10 aluminum solid electrolytic capacitors obtained, the capacitance (frequency 120 Hz), dielectric loss (tan δ, frequency 120 Hz), ESR (100 kHz), and leakage current (LC) 1 minute after application of the rated voltage 6.3 V, respectively. The average value was calculated. Furthermore, a heat resistance / humidity resistance test was performed by holding in an atmosphere of temperature 60 ° C. and humidity 95% for 500 hours. Similarly, the capacitance, tan δ, ESR and leakage current were measured, and the average value was calculated.

  Moreover, the capacitor | condenser element was melt | dissolved with the strong acid after completion | finish of a test, and the iron ion contained in one element was quantified by the high frequency plasma emission spectroscopy. Table 1 shows the measurement results of electrical characteristics of the capacitor, and Table 2 shows the iron ion content in the capacitor element. From the results shown in Tables 1 and 2, iron ions were very small, and the deterioration of the device was within 8% of the initial value, confirming that it had high heat resistance and moisture resistance.

Example 2
As an oxidizing agent solution, a solution of ferric p-toluenesulfonate / butanol = 0.4 mol / 200 ml was prepared.

  Next, on the etched aluminum foil (6 × 4 mm) having a thickness of 200 μm on which the dielectric oxide film is formed, the aniline solution cooled to −10 ° C. and the previously prepared oxidizing solution (−10 ° C.) are applied. Then, chemical oxidative polymerization was performed at room temperature to form a polyaniline layer.

  After the device was washed with ethanol, the temperature was adjusted to pH 6 at a temperature of 60 ° C. containing 0.2 mol / L of 1-nitroso-2-naphthol as a chelate compound and 0.4 mol / L of tetraethylammonium-p-toluenesulfonic acid. It was immersed in a cleaning solution for 10 minutes and then washed with pure water.

  The above process was repeated until the thickness of the polyaniline layer became 8 μm, and then a cathode conductive layer composed of a carbon layer and a silver paste layer was formed, and 10 aluminum solid electrolytic capacitors shown in FIG. 1 were completed.

  With respect to the obtained aluminum solid electrolytic capacitor, in the same manner as in Example 1, the initial value and the capacitance, tan δ, ESR, and leakage current after the heat and humidity resistance test were measured, and the average value was calculated. Further, in the same manner as in Example 1, iron ions in the capacitor element were quantified. Table 1 shows the measurement results of electrical characteristics of the capacitor, and Table 2 shows the iron ion content in the capacitor element. From the results of Tables 1 and 2, the capacitor elements contained very few iron ions, and the deterioration of the elements was within 4% of the initial value, confirming that they had high heat resistance and moisture resistance.

Example 3
A solution of ferric p-toluenesulfonate / butanol = 0.3 mol / 200 ml was prepared as an oxidant solution.

  Next, a pyrrole solution and then the previously prepared oxidant solution are applied onto an etching aluminum foil (6 × 4 mm) having a thickness of 200 μm on which a dielectric oxide film is formed, followed by chemical oxidative polymerization at room temperature, and a polypyrrole layer Formed.

  After the device was washed with ethanol, the temperature was adjusted to pH 4 containing dipyridyl 0.2 mol / L, 2-nitroso-1-naphthol 0.2 mol / L, and p-toluenesulfonic acid 0.4 mol / L as chelate compounds. It was immersed in a cleaning solution at 0 ° C. for 10 minutes and then washed with pure water.

  The above process was repeated until the thickness of the polypyrrole layer became 25 μm, then a cathode conductive layer composed of a carbon layer and a silver paste layer was formed, and 10 aluminum solid electrolytic capacitors shown in FIG. 1 were completed.

  With respect to the obtained aluminum solid electrolytic capacitor, in the same manner as in Example 1, the initial value and the capacitance, tan δ, ESR, and leakage current after the heat and humidity resistance test were measured, and the average value was calculated. Further, in the same manner as in Example 1, iron ions in the capacitor element were quantified. The results of measuring the electrical characteristics of the capacitor are shown in Table 1, and the iron ion content in the capacitor element is shown in Table 2. From the results shown in Tables 1 and 2, it was confirmed that the amount of iron ions was very small, the deterioration of the device was within 2% of the initial value, and it had high heat resistance and moisture resistance.

Example 4
As an oxidizing agent solution, a solution of ferric p-toluenesulfonate / butanol = 0.4 mol / 200 ml was prepared.

  Next, an EDOT solution and then the previously prepared oxidant solution are applied onto a 200 μm thick etched aluminum foil (6 × 4 mm) on which a dielectric oxide film is formed, and the solvent is removed in an atmosphere at 120 ° C. Then, chemical oxidation polymerization was performed to form a PEDOT layer.

  After the device was washed with ethanol, the enol-type dithizone was added as a chelate compound in an amount of 0.4 mol / L, tetraethylammonium-p-toluenesulfonic acid was added in an amount of 0.4 mol / L, and the pH was adjusted to 4 in a cleaning solution at a temperature of 60 ° C. It was immersed for 10 minutes and then washed with pure water.

  After repeating the above steps until the PEDOT layer thickness became 18 μm, a cathode conductive layer composed of a carbon layer and a silver paste layer was formed, and 10 aluminum solid electrolytic capacitors shown in FIG. 1 were completed.

  With respect to the obtained aluminum solid electrolytic capacitor, in the same manner as in Example 1, the initial value and the capacitance, tan δ, ESR, and leakage current after the heat and humidity resistance test were measured, and the average value was calculated. Further, in the same manner as in Example 1, iron ions in the capacitor element were quantified. Table 1 shows the measurement results of electrical characteristics of the capacitor, and Table 2 shows the iron ion content in the capacitor element. From the results shown in Tables 1 and 2, iron ions were very small and the deterioration of the device was within 7% of the initial value, confirming that it had high heat resistance and moisture resistance.

Comparative Example 1
According to Japanese Patent Laid-Open No. 10-251384, a PEDOT layer is formed using an acetonitrile solution of 0.1 mol / L of ferric p-toluenesulfonic acid and 0.4 mol / L of 5-sulfosalicylic acid as an oxidant solution. Washing was performed using pure water and ethanol as the cleaning liquid, and 10 aluminum solid electrolytic capacitors shown in FIG. 1 were completed in the same manner as in Example 1 except that.

  With respect to the obtained aluminum solid electrolytic capacitor, in the same manner as in Example 1, the initial value and the capacitance, tan δ, ESR, and leakage current after the heat and humidity resistance test were measured, and the average value was calculated. Further, in the same manner as in Example 1, iron ions in the capacitor element were quantified. The results of measuring the electrical characteristics of the capacitor are shown in Table 1, and the iron ion content in the capacitor element is shown in Table 2. From the results in Tables 1 and 2, it was confirmed that a large amount of iron ions remained and the capacitor characteristics were deteriorated by 40% or more of the initial value, which was inferior in heat resistance and moisture resistance.

Comparative Example 2
According to Japanese Patent Laid-Open No. 2000-106329, a PEDOT layer is formed using a solution having a composition of 37.15% by mass of iron naphthalenesulfonate, 5.2% by mass of water, and 57.65% by mass of ethanol as an oxidant solution. The aluminum solid electrolytic capacitor shown in FIG. 1 was completed in the same manner as in Example 1 except that it was cleaned using pure water and ethanol as the cleaning liquid.

  With respect to the obtained aluminum solid electrolytic capacitor, in the same manner as in Example 1, the initial value and the capacitance, tan δ, ESR, and leakage current after the heat and humidity resistance test were measured, and the average value was calculated. Further, in the same manner as in Example 1, iron ions in the capacitor element were quantified. The results of measuring the electrical characteristics of the capacitor are shown in Table 1, and the iron ion content in the capacitor element is shown in Table 2. From the results shown in Tables 1 and 2, a large amount of iron ions remained, the capacitor was severely deteriorated due to corrosion inside the device, and measurement of electrical characteristics was impossible.

It is a cross-sectional schematic diagram of an aluminum solid electrolytic capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum foil 2 Dielectric oxide film 3 Solid electrolyte layer 4 Cathode conductive layer 5 Anode terminal part 6 External anode lead 7 Conductive adhesive 8 External cathode lead 9 Exterior resin

Claims (8)

A method for purifying a π-conjugated conductive polymer produced from a monomer of a π-conjugated conductive polymer by an oxidative polymerization reaction using an aromatic sulfonic acid metal salt as an oxidizing agent. A method for purifying a π-conjugated conductive polymer, characterized in that metal ions remaining in the π-conjugated conductive polymer are removed by washing the conductive polymer with a cleaning liquid containing a chelate compound . A π-conjugated conductive polymer produced by an oxidative polymerization reaction using an aromatic sulfonic acid metal salt as an oxidizing agent is purified from at least one selected from the group consisting of pyrrole, alkylenedioxythiophene, aniline and derivatives thereof. The method is characterized in that metal ions remaining in the π-conjugated conductive polymer are removed by cleaning the π-conjugated conductive polymer with a cleaning liquid containing a chelate compound. A method for purifying a π-conjugated conductive polymer. The chelate compound is at least one selected from the group consisting of dipyridyl, terpyridyl, phenanthroline, diphenylthiocarbazone compound, nitrosonaphthol compound, and aminopolycarboxylic acid compound. A method for purifying the π-conjugated conductive polymer according to claim 1. The method for purifying a π-conjugated conductive polymer according to any one of claims 1 to 3, wherein the cleaning liquid containing the chelate compound contains less than 0.2 mol / L of the chelate compound. 5. The π-conjugated system high conductivity according to claim 1, wherein the cleaning liquid containing the chelate compound is controlled to have a pH of 3 to 8 and contains an aromatic sulfonate ion. Molecular purification method. The method for purifying a π-conjugated conductive polymer according to any one of claims 1 to 5, wherein the cleaning liquid containing the chelate compound is controlled at a temperature of 30 to 80 ° C. An electrical energy storage device comprising a π-conjugated conductive polymer obtained by the purification method according to any one of claims 1 to 6. A semiconductor device comprising a π-conjugated conductive polymer obtained by the purification method according to any one of claims 1 to 6.

Images