JP2002020466A - Method for peeling conductive electrolytic polymer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and easy method for peeling a conductive polymer film formed on an electric supply unit simultaneously when a conductive polymer film is subjected to electrolytic polymerization. SOLUTION: An electric supply unit 6 covered with a conductive polymer film 30a through electrolytic polymerization is immersed in an electrolyte 3a, and a DC voltage is applied between a counter electrode 2a and the unit 6 in such a manner that the unit 6 is an anode, thus causing the electrolytic oxidation of the polymer film 30a to chemically deteriorate it. A mechanical vibration by, e.g. an ultrasonic vibration or air bubbling is then imparted to the surface of the unit 6 to peel the deteriorated conductive polymer film 30b from the surface of the unit 6. The deformation of the unit 6 and the occurrence of surface marring can be prevented by this method, so that the unit 6 can be repeatedly used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for peeling a conductive polymer film which has been electrolytically polymerized, and more particularly to a method for removing a conductive substrate surface such as a current collector of an electric double layer capacitor or a precoat (solid electrolyte) of a solid electrolytic capacitor pellet. The present invention relates to a method for peeling off a conductive polymer film simultaneously coated on a power feeder used when forming a conductive polymer film by electrolytic polymerization.

[0002]

2. Description of the Related Art In recent years, conductive polymers have been used as current collectors for electric double layer capacitors and solid electrolytes for solid electrolytic capacitors.

[0003] As a method for forming a conductive polymer, there are a chemical polymerization method and an electrolytic polymerization method. The former is a method used mainly when the substrate is electrically insulating, by immersing the substrate in a mixed low-temperature solution of an oxidizing agent and a monomer, or by immersing, drying, and washing alternately with an oxidizing agent and a monomer. A conductive polymer film is formed on the surface of the substrate by chemical polymerization. The latter method is
Used when the substrate is conductive. For example, a conductive substrate is immersed in an aqueous solution containing a supporting electrolyte, a dopant, a monomer, and the like, and a feeder is brought into contact with the immersion, and a DC voltage is applied for a predetermined time between the feeder and the counter electrode so that the feeder becomes an anode. When applied, the conductive polymer film is electrolytically polymerized on the substrate surface.

[0004] The electrolytic polymerization method has been widely used in a method of manufacturing a capacitor because the electrolytic solution is less likely to deteriorate and the film thickness is easily controlled.

Next, a method for electrolytically polymerizing a conductive polymer film when the conductive polymer film is used as a solid electrolyte of a solid electrolytic capacitor will be described with reference to FIG. First, after anodic oxidation of a valve action metal powder sintered body of tantalum metal or the like in which the anode lead 7 of a tantalum wire or the like is implanted, a prepolymer film of a conductive polymer film such as polypyrrole is coated by a chemical polymerization method. A pellet 5 is formed. This pellet 5 is shown in FIG.
(A) The electrolytic polymerization solution (for example, 6 wt%) in the electrolytic cell 10
(a mixed aqueous solution of sodium p-toluenesulfonate and 2 wt% pyrrole). Then, using a DC power supply 20, a power supply 6 made of a metal material such as stainless steel is brought into contact with or close to the surface of the pellet, and the power supply 6 is used as an anode and the counter electrode 2 (metal electrode made of stainless steel or the like) as a cathode. Is applied for a predetermined time to cover the surface of the pellet 5 with the conductive polymer film 30 as shown in FIG.

[0006]

In the above-described method of contacting a feeder with a pellet and electrolytically polymerizing the electrolyte of the conductive polymer film, as shown in FIG. Of course, the conductive polymer film 30 is simultaneously coated on the immersion part.

In order to coat the conductive polymer film 30 with a stable film thickness on the surface of the pellet 5, it is necessary to keep the surface of the power supply 6 as constant as possible. When electrolytic polymerization is performed by controlling the distance, control of the distance between the power supply and the pellets is also important. Therefore, the conductive polymer film 30 deposited on the surface of the power supply body 6 by the electrolytic polymerization needs to be peeled and reused.

As a method of peeling the conductive polymer film from the surface of the power supply 6, there is a method of mechanically peeling by scratching, thermal decomposition, or the like. However, the power supply tends to be thermally deformed or scratched. In the case of using the pellets, the pellets may be damaged or chipped. In order to prevent the surface of the pellet from being scratched or chipped, there is a method in which the power supply is disposable and is not reused, but this has been a problem of an increase in manufacturing cost and environmental load.

As an example of mechanical peeling by thermal decomposition, Japanese Patent No. 2718353 discloses a method in which a conductive polymer film deposited on an anode lead of a solid electrolytic capacitor is decomposed by heat treatment. It is conceivable to use as a method of removing the conductive polymer film deposited on the power supply when the electrolyte of the solid electrolytic capacitor is electrolytically polymerized. In some cases, the surface of the power supply is insulated by a film generated by thermal decomposition, and it was necessary to chemically treat the power supply in order to use the power supply repeatedly.

An object of the present invention is to remove an electropolymerized conductive polymer film simultaneously deposited on the surface of a feeder when an electroconductive polymer film is electrolytically polymerized on pellets of a solid electrolytic capacitor or other conductive substrates. An object of the present invention is to provide a simple peeling method which solves the above-mentioned problems of the prior art.

[0011]

According to the present invention, there is provided a method for stripping an electropolymerized conductive polymer film, comprising the steps of: preparing a desired conductive polymer film in a first electrolytic solution containing a polymerizable monomer and a first supporting electrolyte; Dipping a conductive substrate forming a first electrode, a first electrode electrically connected to the substrate, and a second electrode acting as a counter electrode to the first electrode; Forming a first conductive polymer film on the surface of the substrate by electrolytic polymerization, wherein the first electrode is used as an anode and the second electrode is used as a cathode for a predetermined time, and Removing the first electrode from the first solution, washing the first electrode in a second electrolytic solution, and immersing the first electrode in the second electrolytic solution as an anode; A third electrode acting as a counter electrode of the first electrode is referred to as a cathode. Electrolytically oxidizing a second conductive polymer film formed simultaneously with the first electrode surface at the time of coating the first conductive polymer film on the substrate surface for a predetermined time. And peeling off the second conductive polymer film from the surface of the first electrode in the second electrolyte solution or the third electrolyte solution by mechanical vibration. You.

In the structure of the present invention, pyrrole, thiophene, furan or a derivative thereof can be used as the polymerizable monomer, and the base is a metal or a valve-acting metal made of Ta, Al or Nb. A conductive polymer chemically polymerized film adhered to an insulating material or the like obtained by anodizing the above can be used.

As the first electrode, a chemically stable and poorly soluble electrode such as stainless steel can be used.

As the first supporting electrolyte of the first electrolytic solution, an alkylbenzenesulfonic acid such as p-toluenesulfonic acid or an alkylnaphthalenesulfonic acid, or an alkali thereof can be used.

In the above structure of the present invention, the second electrolytic solution may be an aqueous solution obtained by removing the polymerizable monomer from the first electrolytic solution, or an aqueous solution of sulfuric acid or phosphoric acid by electrolysis of water. Other aqueous solutions in which reactions do not easily occur can be used.

In the above structure of the present invention, as a method for separating the second conductive polymer film from the first electrode by the mechanical vibration, an air bubbling method or an ultrasonic vibration method is used. Can be.

In the present invention, the second conductive film simultaneously formed on the first electrode (feeder) used when the first conductive polymer film is electrolytically polymerized on the surface of the conductive substrate. The conductive polymer film can be embrittled by electrolytic oxidation and reduced in adhesion to the first electrode, and can be easily separated from the first electrode by bubbling or ultrasonic vibration. Generation of defects such as scratches on the surface of the first electrode (feeder) can be suppressed and reused.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration of an electrolytic apparatus for explaining a step of electrolytically polymerizing a conductive polymer film on a substrate surface in a method for stripping an electropolymerized conductive polymer film according to a first embodiment of the present invention. FIG. FIG. 2 is a schematic configuration diagram of an electrolysis apparatus for explaining a process of deteriorating the electropolymerized conductive polymer film on the surface of the power supply (first electrode) by electrolytic oxidation following the process of FIG. is there. FIG. 3 is a view for explaining a step of peeling the electropolymerized conductive polymer film deteriorated by electrolytic oxidation from the surface of the power supply (first electrode) by mechanical vibration following the step of FIG. 2B. It is a schematic structure figure of an electrolysis device.

In the present embodiment, a conductive polymer film is coated on the surface of a metal (metal plate or metal plating) or an insulating material by chemically polymerizing the conductive polymer film to make it conductive. Although a material can be used, in FIGS. 1 to 3, a valved metal sintered body made of Ta and Nb or an etched foil of Al is anodized, and the surface is pre-coated with a conductive polymer film to make it conductive. An example in which a conductive polymer film is electrolytically polymerized as a solid electrolyte on a capacitor pellet 5 will be described.

First, an anode lead 7 is formed on a Ta metal powder compact.
Was embedded and sintered by a known technique. This sintered body was anodized to form tantalum oxide on the surface. Further, a conductive polymer film of polypyrrole was precoated on the tantalum oxide surface by chemical polymerization to form pellets 5.

Next, as shown in FIG.
The counter electrode 2 is set in an electrolytic cell 10 containing a polymer solution 3 (first electrolytic solution), and a chemically stable hardly soluble power supply 6 (for example, made of stainless steel) is pelletized.
It was set so that it would contact.

Subsequently, a DC voltage is applied between the counter electrode 2 (cathode) and the power feeder 6 (anode) for a predetermined time by using the DC power supply 20 to apply a DC voltage to the surface of the pellet 5 as shown in FIG. The conductive polymer film 30 is electrolytically polymerized. In this electrolytic polymerization step, a conductive polymer film 30a is simultaneously deposited on the surface of the power supply 6 that has come into contact with the polymerization liquid. The pellet 5 in which the conductive polymer is electrolytically polymerized is produced as a solid electrolytic capacitor by baking graphite paste and silver paste, bonding a cathode lead, and packaging the resin with a resin mold or the like.

The polymerization solution 3 includes a polymerizable monomer of pyrrole, thiophene, furan or a derivative thereof and p
A solution containing a supporting electrolyte such as toluenesulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid or an alkali salt thereof can be used. For example, using a polymer solution 3 of 0.05 M pyrrole and 0.3 M p-toluenesulfonic acid aqueous solution or the like, a DC voltage of 6 V is applied between the power supply 6 and the counter electrode 2 for about 30 minutes, and the conductive polymer film 30a
Is electrolytically polymerized. The electrode potential of the power supply 6 during the electropolymerization was set to 1.0 V (based on a silver / silver chloride standard electrode).

Next, after the power feeder 6 is separated from the pellet 5, as shown in FIG. 2A, an electrolytic solution 3 such as a 0.3Mp-toluenesulfonic acid aqueous solution (conductivity: 16 mS / cm) is used.
The power supply 6 was immersed in a. Next, as shown in FIG. 2B, a DC voltage is applied between the counter electrodes 2a using the DC power supply 20a to electrolytically oxidize and deteriorate the conductive polymer film 30a on the power supply 6. The electrolytic oxidation bath voltage is 10
V was applied for 10 minutes to electrolytically oxidize the conductive polymer film 30a. Oxygen gas was also generated from the surface of the power supply 6.
Reference numeral 30b in FIG. 2B indicates a deteriorated conductive polymer film.

Next, as shown in FIG. 3, the ultrasonic wave 50a is applied to the power supply 6 using the ultrasonic vibrator 50 and vibrated to peel off the deteriorated conductive polymer film 30b from the power supply 6.

As described above, according to the present invention, the conductive polymer film deposited on the surface of the power feeder 6 by electrolytic polymerization is chemically degraded (brittle) due to electrolytic oxidation, and the adhesiveness is also reduced, resulting in an ultrasonic wave. By providing 50a, the generation of scratches on the power supply body can be suppressed, the power supply body can be easily peeled off, and the power supply body can be used repeatedly.

In the above-described embodiment, the ultrasonic vibration method is used as a method for peeling the conductive polymer film deteriorated by electrolytic oxidation due to mechanical vibration from the surface of the power supply 6, but air is blown to the surface of the power supply. The conductive polymer film deteriorated by electrolytic oxidation can be easily peeled off from the surface of the power feeder by the method (air bubbling method).

Next, a method of peeling the electropolymerized conductive polymer film according to the second embodiment of the present invention will be described.

In this embodiment, phosphoric acid is used instead of p-toluenesulfonic acid aqueous solution or the like as the electrolytic solution 3a for electrolytic oxidation of the conductive polymer film 30a on the surface of the power supply 6 in the first embodiment. Aqueous solution (conductivity 150μS / c
m) or an aqueous sulfuric acid solution (conductivity 150 μS / cm). Also in the present embodiment, the conductive polymer film formed by electrolytic polymerization could be easily peeled off from the surface of the power supply in the same manner as in the first embodiment.

[0031]

As described above, according to the present invention, the following effects can be obtained. (1) After the conductive polymer film deposited on the surface of the feeder by electrolytic polymerization is electrolytically oxidized in an electrolytic solution and chemically deteriorated, mechanical vibration by ultrasonic vibration or air bubbling is applied to the feeder. When the conductive polymer film is used as an electrolyte for a solid electrolytic capacitor and the like, it can be easily peeled off from the surface of the power supply body, and the power supply body can be used repeatedly because deformation and scratches of the power supply body can be prevented. Manufacturing cost can be reduced. (2) When the conductive polymer film is peeled from the power supply, defects such as scratches of the conductive polymer film deposited on the surface of the base such as a pellet of a solid electrolytic capacitor can be prevented because deformation and scratches of the power supply can be prevented. And the quality of the conductive polymer film can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrolytic apparatus for explaining a step of electrolytically polymerizing a conductive polymer film on a substrate surface in a method for removing an electropolymerized conductive polymer film according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electrolytic apparatus for explaining a step of electrolytically oxidizing an electropolymerized conductive polymer film on a power supply body surface following the step of FIG. 1B.

FIG. 3 is a schematic configuration diagram of an electrolysis apparatus for illustrating a step of peeling an electrolytically oxidized electropolymerized conductive polymer film from the surface of a power feeder (first electrode) following the step of FIG. 2 (b). is there.

FIG. 4 is a schematic configuration diagram of an electrolysis apparatus for describing steps of a conventional method of electrolytic polymerization of a conductive polymer film and a method of peeling the conductive polymer film from a power supply body.

[Explanation of symbols]

 2, 2a Counter electrode 3 Polymer solution 3a Electrolyte solution 5 Pellet 6 Feeder 7 Anode lead 10, 10a Electrolyte bath 20, 20a DC power supply 30, 30a Conductive polymer film 30b Degraded conductive polymer film 50 Ultrasonic vibrator 50a Ultrasonic

Claims (9)

[Claims] An electroconductive substrate for forming a desired electroconductive polymer film in a first electrolytic solution containing a polymerizable monomer and a first supporting electrolyte; An electrode and a second electrode acting as a counter electrode of the first electrode
And immersing the electrode, the first electrode is brought into contact with or close to the base, the first electrode is used as an anode, the second electrode is used as a cathode, electrolysis is performed for a predetermined time, and the surface of the base is Forming a first conductive polymer film by electrolytic polymerization, removing the first electrode from the first solution, washing the first electrode, immersing the first electrode in a second electrolytic solution, Using the first electrode in the second electrolyte as an anode and the third electrode acting as a counter electrode of the first electrode as a cathode, electrolysis is performed for a predetermined time, and the surface of the base is formed on the surface of the first electrode. Electrolytically oxidizing the second conductive polymer film formed simultaneously with the coating of the first conductive polymer film of the above, and in the second electrolyte solution or the third electrolyte solution, The second conductive polymer film is peeled off from the first electrode surface by mechanical vibration. Peeling method of electrolytic polymerization conductive polymer film which comprises a step of. 2. The method according to claim 1, wherein the polymerizable monomer is pyrrole, thiophene, furan or a derivative thereof. 3. The method according to claim 1, wherein the first supporting electrolyte is one selected from the group consisting of alkylbenzenesulfonic acid and alkylnaphthalenesulfonic acid such as p-toluenesulfonic acid, and alkali salts thereof. The method for stripping an electropolymerized conductive polymer film according to claim 1. 4. The electropolymerized conductive polymer film according to claim 1, wherein the base is a metal or an insulating material on which a conductive polymer chemical polymer film is adhered. Peeling method. 5. The method according to claim 1, wherein the insulating material is Ta, Al or Nb.
4. The method for stripping an electropolymerized conductive polymer film according to claim 3, wherein the valve action metal is anodized. 6. The method for stripping an electropolymerized conductive polymer film according to claim 1, wherein the first electrode is a poorly soluble metal electrode. 7. The peeling of the electropolymerized conductive polymer film according to claim 1, wherein the second electrolytic solution is composed of an aqueous solution obtained by removing the polymerizable monomer from the first electrolytic solution. Method. 8. The method according to claim 1, wherein the second electrolyte is an aqueous solution of sulfuric acid or phosphoric acid. 9. The method according to claim 1, wherein an air bubbling method or an ultrasonic vibration method is used as a method for peeling the second conductive polymer film from the first electrode by the mechanical vibration. A method for stripping an electropolymerized conductive polymer film.