JP2005162796A - Method of formation of electroconductive polymer, and manufacturing process of electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of formation of an electroconductive polymer which stably improves the electroconductivity of the electroconductive polymer to the extent possible. <P>SOLUTION: The method of formation of the electroconductive polymer comprises adding a dopant to a monomer, oxidatively polymerizing the monomer to produce a precursor of the electroconductive polymer doped with the dopant and irradiating the precursor of the electroconductive polymer with ultraviolet rays to form the electroconductive polymer. The irradiation of ultraviolet rays enhances the fixation of the dopant to the precursor of the electroconductive polymer and the doping ratio of the electroconductive polymer is stably improved, which makes difference to the prior method of formation of an electroconductive polymer which does not employ ultraviolet irradiation and hence is likely to cause the lowering of a doping ratio over time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for forming a conductive polymer, and a method for manufacturing an electrolytic capacitor using the method for forming a conductive polymer.

  In recent years, electrolytic capacitors are mounted on various electronic devices as one of electronic components suitable for high-frequency applications. With regard to this electrolytic capacitor, for example, in a situation where the digitization, downsizing and speeding up of electronic devices are accelerating, there is a demand for large capacity and low impedance, as well as operational stability and operation. There is also a demand for ensuring reliability and extending the service life.

  An electrolytic capacitor has, for example, an anode made of a valve metal, a dielectric layer made of an oxide film formed by anodizing the surface layer of the anode, an electrolyte layer, and a cathode in this order. Have a structure.

  This electrolytic capacitor is mainly divided into two types according to the type of the electrolyte layer. That is, a liquid electrolytic capacitor having an electrolyte layer (electrolytic solution) made of a liquid material and having conductive characteristics mainly using ionic conductivity, and an electrolyte layer made of a solid material such as a complex salt or a conductive polymer This is a solid electrolytic capacitor having a (solid electrolyte layer) and having conductive characteristics mainly utilizing electronic conductivity. When these two types of electrolytic capacitors are compared in terms of stability of operating characteristics, for example, in liquid electrolytic capacitors, the operating characteristics may deteriorate over time due to leakage or evaporation of the electrolytic solution. As the electrolytic capacitors that can become the mainstream in the future are recently being actively researched and developed for solid electrolytic capacitors instead of liquid electrolytic capacitors, the deterioration of the operating characteristics due to leakage and evaporation of the liquid cannot occur with solid electrolytic capacitors. ing. In this research process on solid electrolytic capacitors, for example, considering the series of operating characteristics such as leakage current characteristics, impedance characteristics, and heat resistance characteristics, the main part of the solid electrolyte layer is composed of manganese dioxide or complex salts and conjugated conductive polymers. Is moving rapidly.

With regard to this solid electrolyte layer, in particular, in order to increase the conductivity of the conductive polymer, a technique for incorporating (doping) an electron donating or electron accepting substance (dopant) into the conductive polymer has already been widely used. in use. Specifically, for example, a technique using arylsulfonic acid or arylphosphoric acid sodium salt as a dopant is known (for example, see Patent Document 1). Moreover, in order to stabilize the electrical conductivity of a solid electrolytic capacitor, a technique for doping a conductive polymer with two kinds of dopants (fixed dopant, mobile dopant) is also known (see, for example, Patent Document 2). .) In particular, recently, research for dramatically improving the conductivity by increasing the doping amount of the dopant has been advanced. For example, a conductivity equivalent to that of a metal (about 10 ⁵ S / cm) can be obtained. A conductive polymer having the same has also been reported.
Japanese Patent No. 3273761 Japanese Patent Publication No. 06-068926

  By the way, in order to ensure the operating characteristics of the solid electrolytic capacitor, for example, it is necessary to stably improve the doping rate of the dopant in order to improve the conductivity as stably as possible. However, although the above-described conventional solid electrolytic capacitor manufacturing method increases the initial doping rate by increasing the doping amount, the doping rate tends to decrease with time, so the conductivity of the solid electrolytic capacitor is stable. There was a problem that it was difficult to improve it. In addition, the deterioration of the doping rate over time becomes more prominent as the doping amount increases. Therefore, in the conventional method of manufacturing a solid electrolytic capacitor, the doping rate increases as the doping amount increases to increase the conductivity of the solid electrolytic capacitor. Tends to deteriorate over time.

  The present invention has been made in view of such problems, and a first object thereof is to provide a method for forming a conductive polymer capable of improving the conductivity of the conductive polymer as stably as possible. There is to do.

  The second object of the present invention is to provide an electrolytic capacitor manufacturing method capable of improving the conductivity of the solid electrolyte layer as stably as possible using the method for forming a conductive polymer of the present invention. Is to provide.

  The method for forming a conductive polymer according to the present invention includes a step of generating a conductive polymer precursor so as to include the dopant by adding a dopant to the monomer and polymerizing the monomer, and a conductive polymer precursor. A process of forming a conductive polymer by irradiating the body with electromagnetic waves.

  In the method for forming a conductive polymer according to the present invention, a conductive polymer precursor is generated so as to include a dopant, and then the conductive polymer precursor is irradiated with electromagnetic waves to thereby form the conductive polymer. Is formed. Based on this electromagnetic wave irradiation, the fixability of the dopant to the conductive polymer precursor is improved, so that unlike conventional methods of forming a conductive polymer, the electromagnetic wave is not irradiated and the doping rate tends to decrease over time. In addition, the doping rate of the conductive polymer is stably improved.

  The method for producing an electrolytic capacitor according to the present invention is a method for producing an electrolytic capacitor having a solid electrolyte layer, and the step of forming the solid electrolyte layer is performed by adding a dopant to a monomer and polymerizing the monomer. A step of generating a conductive polymer precursor so as to include a dopant, and forming a conductive polymer by irradiating the conductive polymer precursor with an electromagnetic wave so as to include the conductive polymer. And a step of forming a layer.

  In the method for producing an electrolytic capacitor according to the present invention, since the solid electrolyte layer is formed using the method for forming a conductive polymer of the present invention, the doping rate of the solid electrolyte layer is stably improved.

  According to the method for forming a conductive polymer according to the present invention, the doping rate of the conductive polymer is stably improved by irradiating the conductive polymer precursor containing the dopant with electromagnetic waves. The conductivity of the polymer can be improved as stably as possible. As a result, in particular, the conductivity of the conductive polymer can be maintained as much as possible even in a high temperature environment.

  According to the method for producing an electrolytic capacitor according to the present invention, a solid electrolyte layer is formed using the method for forming a conductive polymer of the present invention, and the doping rate of the solid electrolyte layer is stably improved. The conductivity of the capacitor can be improved as stably as possible, and in particular, the conductivity of the electrolytic capacitor can be maintained as much as possible even in a high temperature environment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, with reference to FIG. 1, the conductive polymer formed using the formation method of the conductive polymer which concerns on one embodiment of this invention is demonstrated easily. FIG. 1 shows a cross-sectional configuration of the conductive polymer 1.

  The conductive polymer 1 includes, for example, an electrolytic capacitor, a battery, an electrode, a transistor, an ultraviolet shielding material, an antistatic agent, a capacitor, a diode, an electrochromic element, an electroluminescence (EL) element, a solar cell, and light. It constitutes a part of an electronic component typified by a recording medium or various sensors. For example, as shown in FIG. 1, the conductive polymer 1 is formed on a predetermined substrate 2, that is, formed into a film on the substrate 2.

  In particular, the conductive polymer 1 is formed by irradiating the conductive polymer precursor 1Z with electromagnetic waves, and is doped with a dopant for increasing conductivity. The conductive polymer precursor 1Z is generated by adding a dopant to a monomer and polymerizing the precursor as a precursor for forming the conductive polymer 1. The substrate 2 is a support used for forming the conductive polymer 1 into a film. The materials of the conductive polymer 1 and the base 2 will be described later.

  Next, a method for forming the conductive polymer 1 shown in FIG. 1 will be described with reference to FIGS. FIG. 2 is for explaining the flow of the process of forming the conductive polymer 1.

  When forming the conductive polymer 1, after preparing the base | substrate 2, first, a monomer solution is prepared (step S101). When preparing this monomer solution, the monomer for producing the conductive polymer 1, the dopant for increasing the conductivity of the conductive polymer 1, the monomers and the dopant And a solvent for dispersing. In particular, when preparing the monomer solution, for example, together with the above-described monomer, dopant and solvent, an oxidant for oxidative polymerization of the monomer is included.

The material used when preparing a monomer solution is as follows, for example. That is, as a monomer, for example, thiophene, aniline, pyrrole, furan, thiophene vinylene, isothianaphthene, acetylene, p-phenylene, phenylene vinylene, methoxy vinylene, methoxy phenylene, phenylene sulfide, phenylene oxide, anthracene, naphthalene , Pyrene, azulene, selenophene, tellurophene and at least one of the group comprising these derivatives, preferably at least one of thiophene, aniline, pyrrole and furan. As the dopant, for example, any of donor-type or acceptor-type dopants can be used. Examples of the donor-type dopant include alkali metals such as lithium (Li), sodium (Na), and potassium (K), and alkaline earth metals such as calcium (Ca). On the other hand, examples of acceptor-type dopants include halogens such as chlorine (Cl ₂ ), bromine (Br ₂ ), and iodine (I ₂ ), phosphorus fluoride (PF ₃ ), arsenic fluoride (AsF ₅ ), and fluorine. Lewis acids such as boron fluoride (BF ₃ ) and protonic acids such as hydrogen fluoride (HF), hydrogen chloride (HCl), nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ) or perchloric acid (HClO ₄ ) Or alkylbenzene sulfonic acid (for example, paratoluene sulfonic acid), alkyl naphthalene sulfonic acid or a salt thereof, iron chloride (FeCl ₃ ), iron perchlorate (FeOCl ₂ ), titanium chloride (TiCl ₄ ), or tungsten chloride (WCl) ₃₎ and a transition metal compound, such as, chlorine ion (Cl ^-), bromine ion (Br ^-), iodide ion (I ^-), perchlorate ion (ClO ₄ ^-) Fluoride phosphorus (PF ₃ ^-), boron fluoride ions (BF ₃ ^-) or fluoride arsenic ion (AsF ₃ ^-) include an electrolyte anion such. As the solvent, for example, water or an organic solvent such as butanol is used. Examples of the oxidizing agent include halogens such as iodine or bromine, metal halides such as silicon pentafluoride (SiF ₅ ), protonic acids such as sulfuric acid, oxygen compounds such as sulfur trioxide (SO ₃ ), Sulfates such as cerium sulfate (Ce (SO ₄ ) ₂ ), persulfates such as sodium persulfate (Na ₂ S ₂ O ₈ ), peroxides such as hydrogen peroxide (H ₂ O ₂ ), An alkylbenzene sulfonate (for example, iron paratoluene sulfonate) is used.

  The monomer solution may further contain various additives in addition to the monomer, dopant, solvent and oxidant described above, for example. Examples of the “additive” include an antioxidant (for example, nitrophenol).

  As the substrate 2, for example, glass, ceramic, stainless steel, metal, resin, cotton cloth or fiber is used. Among these series of materials, for example, the metal includes aluminum, and the resin includes acrylic, polycarbonate, polyethylene terephthalate (PET), and the like. For example, when the conductive polymer 1 is used as a solid electrolyte layer of an electrolytic capacitor, the valve action of aluminum, titanium, tantalum, niobium or the like is used as the substrate 2. A metal foil or a valve action metal sintered body is used. As these valve action metal foil or valve action metal sintered body, for example, the surface enlargement process is performed in advance and the surface uneven structure is formed, and similarly, the chemical conversion process is performed in advance to form the dielectric layer. It is preferable to use what is formed. For example, when the conductive polymer 1 is used as a hole injection layer of an EL element, a transparent electrode such as indium tin oxide (ITO) is used as the substrate 2.

  Subsequently, for example, a monomer solution is applied to the substrate 2 by using a coating method typified by a spray method, a roller method, a spin coating method, a dip method, or the like, whereby a monomer is applied to one surface of the substrate 2. A solution is supplied (step S102). When supplying the monomer solution to one surface of the substrate 2, an immersion method is used instead of using the above-described coating method, that is, the substrate 2 is simply immersed in the monomer solution. Good.

  Subsequently, the monomer in the monomer solution supplied to one surface of the substrate 2 is polymerized to generate the conductive polymer precursor 1Z doped with the dopant (step S103). Thereby, one surface of the base 2 is covered with the conductive polymer precursor 1Z. When producing this conductive polymer precursor 1Z, for example, by heating the monomer solution using a heating device such as a dryer, the oxidizing agent in the monomer solution is used. The monomer is oxidatively polymerized. At this time, the heating temperature can be appropriately set in consideration of the heat-resistant temperature of the base 2 and the like, for example, 40 ° C. to 180 ° C. In this case, in particular, when the heating temperature is too high, the dopant doped in the conductive polymer precursor 1Z is desorbed, or the conductive polymer precursor 1Z itself is oxidized and deteriorated, whereby the conductivity is increased. In order to prevent this decrease in conductivity, the heating temperature is preferably 40 ° C to 150 ° C. The heating time can be appropriately set in consideration of the reactivity of the monomer (polymerizability), the reactivity of the oxidant (oxidizing power), and the like, and is, for example, 5 minutes to 24 hours.

  The conductive polymer precursor 1Z produced through this oxidative polymerization reaction is, for example, polythiophene, polyaniline, polypyrrole, polyfuran, polythiophene vinylene, polyisothianaphthene, polyacetylene, poly-p-phenylene, polyphenylene vinylene, polymethoxy vinylene. , Polymethoxyphenylene, polyphenylene sulfide, polyphenylene oxide, polyanthracene, polynaphthalene, polypyrene, polyazulene, polyselenophene, polytellurophene and at least one of these derivatives. As the conductive polymer precursor 1Z, for example, a conjugated polymer having a one-dimensional chain in the polymer skeleton and having an electron donating function or an electron accepting function (so-called dopamine function) is preferable. Among these, considering the ease of production using an oxidative polymerization reaction, for example, at least one selected from the group comprising polythiophene, polyaniline, polypyrrole, polyfuran and derivatives thereof is preferable. Specifically, this type of conductive polymer precursor 1Z is, for example, a polythiophene derivative, and is produced by oxidative polymerization of 3,4-ethylenedioxythiophene as a monomer. Thiophene is mentioned.

Subsequently, the conductive polymer precursor 1Z is irradiated with electromagnetic waves (step S104) to form the conductive polymer 1 (step S105). Specifically, for example, metal halide lamps (HQI (quartz arc tube) or HCI (ceramic arc tube)), mercury lamps (low pressure type or high pressure type), halogen lamps, blue fluorescent lamps, black lights or fluorescent sterilization lamps, etc. Using a light source, the conductive polymer precursor 1Z is irradiated with ultraviolet rays as electromagnetic waves. The irradiation conditions of the ultraviolet, for example, wavelength = about 400nm or less, the irradiation intensity = about ^{1mW / cm 2 ~300mW / cm 2} , and the accumulated light quantity = about ^{100mJ / cm 2 ~50000mJ / cm 2} . When the conductive polymer precursor 1Z is irradiated with ultraviolet rays, for example, the irradiation treatment may be performed in the atmosphere, or in an inert gas such as nitrogen (N ₂ ) or argon (Ar). You may make it perform in. In this case, in particular, when the irradiation treatment is performed in the atmosphere, the polymer chain is excessively oxidized due to the presence of the active oxygen species generated during the irradiation treatment, and as a result, the conductive polymer precursor 1Z. Therefore, in order to prevent a decrease in the conductivity of the conductive polymer precursor 1Z, it is preferable to perform the irradiation treatment in an inert gas rather than in the atmosphere. This ultraviolet irradiation treatment improves the fixability of the dopant to the conductive polymer precursor 1Z.

  Finally, after washing the conductive polymer 1, the conductive polymer 1 is dried (step S106). By this washing treatment, unreacted monomers contained in the conductive polymer 1, excess dopant not doped in the conductive polymer 1, or used oxidizer is washed away and removed. . As the cleaning liquid for cleaning the conductive polymer 1, a liquid that does not dissolve the conductive polymer 1 and does not erode the base 2 can be used as appropriate, for example, water, alcohol, acetone, or hexane. Etc. Thereby, the conductive polymer 1 shown in FIG. 1 is completed.

  In the method for forming the conductive polymer 1 according to the present embodiment, after the conductive polymer precursor 1Z doped with the dopant is generated, the conductive polymer precursor 1Z is irradiated with ultraviolet rays to make the conductive polymer precursor 1Z conductive. Since the polymer 1 is formed, as described above, the fixability of the dopant to the conductive polymer precursor 1Z is enhanced based on the irradiation with ultraviolet rays. In this case, the doping rate of the conductive polymer 1 is stably improved, unlike the conventional method for forming a conductive polymer which is not irradiated with ultraviolet rays and the doping rate is likely to decrease with time. Of course, the stable improvement of the doping rate can be similarly obtained even when the doping amount is increased for the purpose of increasing the conductivity of the conductive polymer 1. Therefore, in the present embodiment, the conductivity of the conductive polymer 1 can be improved as stably as possible. As a result, in particular, the conductivity of the conductive polymer 1 can be maintained as much as possible even in a high temperature environment.

  Here, if it supplements regarding the formation method of the electroconductive polymer 1, the irradiation process of the ultraviolet-ray which is the characteristics of this Embodiment is the photopolymerization reaction generally known, ie, a photopolymerization type monomer. This is different from the ultraviolet irradiation treatment for the purpose of polymerization. That is, the ultraviolet irradiation treatment in the present embodiment is not applied to the monomer in order to photopolymerize the monomer to produce the conductive polymer precursor 1Z. After forming the conductive polymer precursor 1Z by completing the polymerization reaction of the body in the process, as described above, the conductive polymer precursor 1Z is formed into the conductive polymer precursor 1Z for the purpose of improving the fixability of the dopant. It is given to.

  In the present embodiment, when the conductive polymer precursor 1Z is formed, a single solution (monomer solution) containing a monomer, a dopant, and an oxidant is used. However, the present invention is not necessarily limited to this. For example, two or more kinds of solutions containing a monomer, a dopant, and an oxidizing agent in any combination may be used instead of the single solution described above. . Specifically, for example, two types of a solution containing a monomer and a dopant (monomer solution) and a solution containing an oxidant (oxidant solution) may be used. Also in this case, since the conductive polymer precursor 1Z can be generated on the substrate 2 by using the above-described two kinds of solutions in order, the same effect as in the above embodiment can be obtained.

  In the present embodiment, the conductive polymer precursor 1Z is generated in a liquid phase system using a solution (monomer solution) containing a monomer, a dopant, and an oxidizing agent. For example, the conductive polymer precursor 1Z may be generated in a gas phase system instead of a liquid phase system. In this case, for example, a solution containing an oxidant / dopant (oxidant / dopant solution) is prepared, and the oxidant / dopant solution is applied to one surface of the substrate 2 and then the substrate 2 is introduced into the monomer vapor. As in the case of the liquid phase system, the conductive polymer precursor 1Z can be formed on one surface of the substrate 2 by subjecting the monomer to oxidative polymerization using an oxidizing agent. Even in this case, the same effect as the above embodiment can be obtained.

  Further, in the present embodiment, ultraviolet rays are used as the electromagnetic wave irradiated to the conductive polymer precursor 1Z. However, the present invention is not limited to this, and the conductive polymer precursor 1Z is damaged (for example, altered). As long as it is possible to improve the fixability of the dopant without imparting or the like), the type of electromagnetic wave irradiated to the conductive polymer precursor 1Z can be freely changed. Specifically, for example, X-rays or the like may be used as electromagnetic waves instead of ultraviolet rays. Even in this case, the same effect as the above embodiment can be obtained.

  Above, the description regarding the formation method of the conductive polymer which concerns on one embodiment of this invention is complete | finished.

  Next, the manufacturing method of the electrolytic capacitor using the formation method of the conductive polymer of this invention is demonstrated.

  First, with reference to FIG. 3 and FIG. 4, the structure of the electrolytic capacitor manufactured using the manufacturing method of an electrolytic capacitor is demonstrated easily. 3 and 4 show the configuration of the main part (capacitor element 10) of the electrolytic capacitor, FIG. 3 shows the external configuration, and FIG. 4 is an enlarged cross-sectional configuration along the line IV-IV shown in FIG. As shown.

  In this electrolytic capacitor, an anode lead and a cathode lead (both not shown) are connected to the capacitor element 10 shown in FIGS. 3 and 4 so that both the anode lead and the cathode lead are partially exposed. The capacitor element 10 has a structure in which the periphery is covered with a mold resin (not shown). The capacitor element 10 generates an electrical reaction as a main part of the electrolytic capacitor. For example, as shown in FIGS. 3 and 4, the anode 11 and the periphery (one end) of the anode 11 are partially formed. A dielectric layer 12 provided to cover the dielectric layer 12, a solid electrolyte layer 13 provided to cover the periphery of the dielectric layer 12, and a cathode 14 provided to cover the periphery of the solid electrolyte layer 13. In other words, the anode 1, the dielectric layer 12, the solid electrolyte layer 13 and the cathode 14 are laminated in this order.

  The anode 11 has an uneven surface (or roughened) surface uneven structure, for example, a valve metal such as aluminum (Al), titanium (Ti), tantalum (Ta), or niobium (Nb). It is comprised by. Specifically, the anode 11 is a metal foil such as aluminum or titanium, or a metal sintered body such as tantalum or niobium. The details of the surface uneven structure of the anode 11 that has been enlarged will be described later (see FIG. 5).

The dielectric layer 12 is an oxide film formed by, for example, anodizing the surface layer of the anode 11 made of a valve metal. For example, when the anode 11 is made of aluminum, the dielectric layer 12 is made of aluminum oxide (Al ₂ O ₃ ; hereinafter simply referred to as “alumina”).

  The solid electrolyte layer 13 includes the conductive polymer 1 described in the above embodiment. Since the conductive polymer 1 and the dopant material doped in the conductive polymer 1 have already been described in detail, the description thereof is omitted. The capacitor element 10 provided with the solid electrolyte layer 13 is a so-called solid electrolytic capacitor element.

  The cathode 14 has, for example, a laminated structure in which a carbon (graphite) layer 14A and a silver (Ag) layer 14B are laminated. However, the anode 14 does not necessarily have a laminated structure, and may have, for example, a single layer structure.

  For reference, both the anode lead and the cathode lead are, for example, a metal such as iron (Fe) or copper (Cu), or a plating treatment (for example, tin (Sn) plating or tin lead (SnPb)) on these metals. It is made of a plated metal subjected to plating, and is connected to the anode 11 and the cathode 14 of the capacitor element 10, respectively. The mold resin is made of an insulating resin such as an epoxy resin, for example.

  Next, a detailed configuration of the capacitor element 10 will be described with reference to FIG. FIG. 5 shows a partially enlarged cross-sectional configuration of the capacitor element 10 shown in FIG.

  In the capacitor element 10, for example, as shown in FIG. 5, a dielectric layer 12, a solid electrolyte layer 13, and a cathode 14 (carbon layer 14A, silver layer 14B) are laminated in this order so as to cover the anode 11. In the capacitor element 10, as described above, in order to realize a high capacity by increasing the surface area of the anode 11, the anode 11 is subjected to a surface enlargement process (or a surface roughening process). That is, the anode 11 has a fine surface uneven structure. Accordingly, the dielectric layer 12 formed so as to cover the anode 11 has a fine uneven structure, and the solid electrolyte layer 13 is provided so as to cover the dielectric layer 12 having this fine uneven structure. It has been. In particular, the dielectric layer 12 constitutes a plurality of pores 12H as recesses in the concavo-convex structure, and the solid electrolyte layer 13 partially enters the plurality of pores 12H constituted by the dielectric layer 12. It is out.

  Next, a method for manufacturing an electrolytic capacitor including the capacitor element 10 shown in FIGS. 3 to 5 will be described with reference to FIGS. FIG. 6 is for explaining the flow of the manufacturing process of the electrolytic capacitor.

  When manufacturing an electrolytic capacitor, first, the capacitor element 10 shown in FIGS. 3 to 5 is formed. That is, first, a valve action metal foil (for example, an aluminum foil or a titanium foil) is prepared as a material for forming the anode 11, and then the valve action metal foil is subjected to a surface enlargement process using chemical or electrochemical etching. Thus, the anode 11 having a fine surface uneven structure is formed (step S201). As a material for forming the anode 11, for example, a valve metal sintered body such as tantalum or niobium can be used instead of the valve metal foil described above. When forming the anode 11, for example, an untreated valve action metal foil that has not been subjected to a surface enlargement treatment as described above is used, and the valve action metal foil is separately subjected to a surface enlargement treatment. Instead, in order to save the effort required for the surface enlargement process, a treated valve metal foil or a valve metal sintered body that has been subjected to the surface enlargement process in advance may be used.

  Subsequently, the surface layer of the anode 11 is anodized to form the dielectric layer 12 made of an oxide film so as to partially cover the periphery of the anode 11 (step S202). The dielectric layer 12 has a concavo-convex structure corresponding to the surface concavo-convex structure of the anode 11, and constitutes a plurality of pores 12H as concave portions in the concavo-convex structure. As the dielectric layer 12, for example, when an aluminum-enlarged foil is used as the material for forming the anode 11, the dielectric layer 12 made of alumina can be formed. When the dielectric layer 12 is formed, for example, after the anode 11 is immersed in the chemical conversion solution, a voltage is applied to the anode 12 to advance the anodic oxidation reaction. As the chemical conversion solution, for example, a buffer solution such as ammonium borate, ammonium phosphate, or organic acid ammonium is used, and preferably an aqueous solution of ammonium adipate is used as the organic acid ammonium. The voltage applied to the anode 11 can be freely set within a range of several V to several hundred V, for example, depending on the formation thickness of the dielectric layer 12.

  Subsequently, by forming the conductive polymer 1 using the method for forming a conductive polymer described in the above embodiment, the solid electrolyte layer 13 including the conductive polymer 1 doped with the dopant is formed. (Step S203). Since the method for forming the conductive polymer 1 has already been described in detail in the above embodiment, the description thereof is omitted.

  Subsequently, the cathode 14 is formed so as to cover the periphery of the solid electrolyte layer 13 (step S204). When the cathode 14 is formed, for example, a carbon paste is applied around the solid electrolyte layer 13 and dried to form the carbon layer 14A, and then a silver paste is further applied onto the carbon layer 14A. By drying, the silver layer 14B is formed so as to have a laminated structure of the carbon layer 14A and the silver layer 14B. Thereby, the capacitor element 10 having a laminated structure in which the anode 11, the dielectric layer 12, the solid electrolyte layer 13, and the cathode 14 are laminated in this order is completed (see FIGS. 3 to 5).

  After the capacitor element 10 is formed, an electrolytic capacitor is assembled using the capacitor element 10. That is, for example, after connecting the anode lead to the anode 11 of the capacitor element 10 and connecting the cathode lead to the cathode 14 (step S205), both the anode lead and the cathode lead are partially exposed. The periphery of the capacitor element 10 is covered with a mold resin (step S206). As a result, the anode lead and the cathode lead are connected to the capacitor element 10, and the capacitor element 10 has a structure in which the periphery of the capacitor element 10 is covered with the mold resin so that both the anode lead and the cathode lead are partially exposed. Is completed. When the anode lead and the cathode lead are connected to the capacitor element 10, for example, the capacitor element 10 may be directly connected using a welding process or a caulking process, or a conductive adhesive is used. You may make it connect indirectly.

  In this electrolytic capacitor manufacturing method, the solid electrolyte layer 13 is formed by forming the conductive polymer 1 using the method for forming a conductive polymer of the present invention. By the effect | action which carried out, the electrical conductivity of the solid electrolyte layer 13 improves stably. Therefore, the conductivity of the electrolytic capacitor can be improved as stably as possible, and in particular, the conductivity of the electrolytic capacitor can be maintained as much as possible even in a high temperature environment.

  In addition, the manufacturing procedures, operations, and modifications other than those described above regarding the method for manufacturing an electrolytic capacitor are the same as those in the above embodiment.

  Next, specific examples of the present invention will be described.

(Example 1)
Using the conductive polymer forming method described in the above embodiment, the conductive polymer 1 was formed in a liquid phase system. That is, first, as a substrate 2 (see FIG. 1), a glass substrate (26 mm × 76 mm × 1 mm) is ultrasonically cleaned with a neutral detergent solution and then rinsed thoroughly with double distilled water, and then the substrate 2 is dried. And dried. Subsequently, 3,4-ethylenedioxythiophene as a monomer (Baytron Co., Ltd. (Baytron M (trade name)), and as a dopant and oxidant, 50% butanol solution of iron (III) paratoluenesulfonate (manufactured by Bayer Co., Ltd.) After fully cooling Baytron C (trade name) with ice water, weigh out 0.867 g and 10.4 g of these monomers and dopant / oxidizer, and mix and stir with a magnetic stirrer while cooling with ice water. Thus, a monomer solution was prepared. Subsequently, the monomer solution was applied to one surface of the substrate 2 using a spin coating method. At this time, as spin coating conditions, the number of rotations was set to 2000 rpm and the rotation time was set to 2 minutes. Subsequently, after leaving the substrate 2 coated with the monomer solution at room temperature for about 1 hour, the substrate 2 is heated, and the monomer is oxidatively polymerized using an oxidizing agent, whereby the substrate 2 is heated. Polyethylenedioxythiophene was produced as a conductive polymer precursor 1Z on one side. At this time, the heating conditions were heating temperature = 100 ° C. and heating time = 15 minutes. Subsequently, the conductive polymer 1 was formed by irradiating the conductive polymer precursor 1Z with ultraviolet rays using a mercury lamp. At this time, the irradiation conditions of ultraviolet rays were as follows: irradiation intensity = 100 mW / cm ² , integrated light amount = 30000 mJ / cm ² , and irradiation time = 5 minutes. Finally, the conductive polymer 1 is thoroughly washed with distilled water to wash away unreacted monomers, excess dopant, and used oxidizing agent, and then the conductive polymer 1 is dried. It was.

(Example 2)
The conductive polymer 1 was formed in a gas phase system using the method for forming a conductive polymer described as a modification in the above embodiment. That is, first, a substrate 2 similar to that of Example 1 was prepared, and then a spin coat method was used to form a 50% butanol solution of paratoluenesulfonic acid iron (III) 50% butanol (Bayer) on one surface of the substrate 2 as a dopant / oxidizer solution. Baytron C (trade name) manufactured by Co., Ltd.) was applied. At this time, as spin coating conditions, the number of rotations was set to 2000 rpm and the rotation time was set to 2 minutes. Subsequently, the base 2 coated with the oxidizing agent solution was put into a glass container, and the base 2 was fixed so as to be separated from the bottom surface of the glass container by about 1.5 cm, and then the glass container was sealed. Subsequently, after supplying 5 mL of pyrrole distilled and purified as a monomer into the glass container, the inside of the glass container is heated, and the monomer is vapor-phase polymerized using an oxidant, whereby one surface of the substrate 2 is obtained. Polypyrrole was produced as a conductive polymer precursor 1Z. At this time, the heating conditions were heating temperature = 100 ° C. and heating time = 15 minutes. Subsequently, after the conductive polymer 1 was formed by irradiating the conductive polymer precursor 1Z with ultraviolet rays under the same conditions as in Example 1, the conductive polymer 1 was washed. When the film thickness of the conductive polymer 1 (polypyrrole) formed in the gas phase system was examined, the film thickness was 0.08 μm.

(Comparative Example 1)
A conductive polymer (polyethylenedioxythiophene) was formed through the same procedure as in Example 1 except that the conductive polymer precursor 1Z produced in the liquid phase system was not irradiated with ultraviolet rays.

(Comparative Example 2)
A conductive polymer (polypyrrole) was formed through the same procedure as in Example 2 except that the conductive polymer precursor 1Z generated in the gas phase system was not irradiated with ultraviolet rays.

  When the various characteristics of the conductive polymers of Examples 1 and 2 and Comparative Examples 1 and 2 were examined, the following results were obtained.

  First, when the doping rate of the conductive polymer was examined, the results shown in FIGS. 7 and 8 were obtained. 7 and 8 show changes in light absorption characteristics of the conductive polymer. FIG. 7 shows the results for Example 1 and Comparative Example 1 (polyethylenedioxythiophene). FIG. 8 shows Example 2 and Comparative Example 2. The result regarding (polypyrrole) is represented. 7 and 8, the “horizontal axis” represents the wavelength (nm), and the “vertical axis” represents the absorbance. “7A” and “7B” in FIG. 7 and “8A” and “8B” in FIG. 8 indicate the results regarding Example 1, Comparative Example 1, Example 2, and Comparative Example 2, respectively. In addition, when investigating the doping rate of the conductive polymer, a spectrophotometer (UV-3101PC) manufactured by Shimadzu Corporation was used, and the ultraviolet-visible spectral absorption spectrum in the wavelength range of 300 nm to 1800 nm for the conductive polymer. Was measured.

Regarding the doping rate of the dopant doped in the conductive polymer, it is possible to grasp the change of the doping rate based on the spectrum measurement result by measuring the ultraviolet-visible spectral absorption spectrum of the conductive polymer. Is possible. That is, with respect to the doping rate of the conductive polymer, it is generally known that when the doping rate increases, the light absorption tendency in the near-infrared region increases in the spectrum measurement result. The phase difference between the doping rate and the spectrum measurement result has already been confirmed for a system in which, for example, polythiophene as a conductive polymer is doped with boron fluoride ion (BF ₄ ⁻ ) as a dopant. This phenomenon is considered to be caused by the formation of a kind of band based on the generation of polaron or bipolaron between the valence band and the conduction band of the conductive polymer.

  As can be seen from the results shown in FIG. 7, the spectrum measurement results are compared between Example 1 (7A) and Comparative Example 1 (7B) in the case where the conductive polymer is composed of polyethylene dioxythiophene. Then, the absorbance in the near-infrared region (wavelength region of about 750 nm to about 1800 nm) was higher in Example 1 than in Comparative Example 1, that is, the light absorption tendency was higher. From this, it was confirmed that in Example 1, the doping rate increased as compared with Comparative Example 1.

  Further, as can be seen from the results shown in FIG. 8, the spectrum measurement results between Example 2 (8A) and Comparative Example 2 (8B) are the same when the conductive polymer is composed of polypyrrole. As compared with Comparative Example 2, the absorbance in the near-infrared region was higher in Example 2 than in Comparative Example 2, that is, the light absorption tendency was higher. From this, it was confirmed that in Example 2, the doping rate increased as compared with Comparative Example 2.

In addition, although it does not explain after showing data concretely, when the doping rate was examined for the conductive polymers of Examples 1 and 2 while changing the irradiation conditions (irradiation intensity, accumulated light amount) of the ultraviolet rays, the irradiation intensity and ^{1mW / cm 2 ~300mW / cm 2} , when the accumulated light amount was set to ^{100mJ / cm 2 ~50000mJ / cm 2} , similar results to the case shown in FIGS. 7 and 8 were obtained. From this, it was confirmed that the doping rate of the conductive polymer increases by setting the irradiation intensity of ultraviolet rays and the integrated light quantity within the above ranges.

  Subsequently, when the stability of the conductivity of the conductive polymer was examined, the results shown in Table 1 and Table 2 were obtained. Tables 1 and 2 show changes in resistance characteristics of the conductive polymer. Table 1 shows the results regarding Example 1 and Comparative Example 1 (polyethylenedioxythiophene). Table 2 shows Example 2 and Comparative Example 2. The result regarding (polypyrrole) is represented. When investigating the stability of the conductivity of a conductive polymer, the resistance value (kΩ; initial resistance value) of each conductive polymer is measured, and each of these conductive polymers is measured in a high temperature environment of 125 ° C. After standing for 500 hours, the resistance value (kΩ; resistance value after standing) was measured again. In Tables 1 and 2, the resistance value of the conductive polymer (“initial resistance value”, “resistance value after standing”) and the type of conductive polymer (“conductive polymer”) by the time of confirmation are shown. In addition, the presence or absence of ultraviolet irradiation (“ultraviolet irradiation”) is also shown.

  As can be seen from the results shown in Table 1, when the conductive polymer is composed of polyethylene dioxythiophene, the initial resistance values are 0.87 kΩ and 2.32 kΩ in Example 1 and Comparative Example 1, respectively. The resistance values after standing were 655 kΩ and 15600 kΩ in Example 1 and Comparative Example 1, respectively. That is, both the initial resistance value and the resistance value after being left are significantly smaller in Example 1 than in Comparative Example 1, and in Example 1, the conductivity is higher and the conductivity is less likely to change than in Comparative Example 1. became. From this, it was confirmed that the conductive polymer of Example 1 stably improved the conductivity, unlike the conductive polymer of Comparative Example 1.

  Further, as can be seen from the results shown in Table 2, regarding the case where the conductive polymer is composed of polypyrrole, the initial resistance values are 30.1 kΩ and 43.4 kΩ in Example 2 and Comparative Example 2, respectively. The resistance values after standing were 2180 kΩ and 24800 kΩ in Example 2 and Comparative Example 2, respectively. That is, also in this case, both the initial resistance value and the resistance value after being left are smaller in Example 2 than in Comparative Example 2, and in Example 2, the conductivity is higher than that in Comparative Example 2 and the conductivity is higher. It became hard to change. From this, it was confirmed that the conductive polymer of Example 2 stably improved the conductivity, unlike the conductive polymer of Comparative Example 2.

  While the present invention has been described with reference to the embodiments and examples, the present invention is not limited to these embodiments and examples, and various modifications can be made. Specifically, in the above-described embodiments and examples, the method for forming a conductive polymer has been described, and the method for forming the conductive polymer has been specifically described as an application example of the method for forming the conductive polymer. However, the present invention is not necessarily limited thereto, and the method for forming a conductive polymer of the present invention can also be applied to a method for manufacturing electronic components other than electrolytic capacitors. As described above, the “other electronic component” includes, for example, a battery, an electrode, a transistor, an ultraviolet shielding material, an antistatic agent, a capacitor, a diode, an electrochromic element, an EL element, a solar cell, an optical recording medium, or Examples include various sensors. Even when the method for forming a conductive polymer of the present invention is applied to these other electronic component manufacturing methods, the same effects as those of the above-described embodiment and examples can be obtained.

  The method for forming a conductive polymer according to the present invention can be applied to a manufacturing process of various electronic parts represented by an electrolytic capacitor in which a main part that generates an electrical reaction is composed of a solid material (conductive polymer). Is possible.

It is sectional drawing showing the cross-sectional structure of the conductive polymer formed using the formation method of the conductive polymer which concerns on one embodiment of this invention. It is a flowchart for demonstrating the flow of the formation process regarding the formation method of the conductive polymer which concerns on one embodiment of this invention. It is an external view showing the external appearance structure of the capacitor | condenser element manufactured using the manufacturing method of the electrolytic capacitor of this invention. FIG. 4 is an enlarged cross-sectional view illustrating a cross-sectional configuration along line IV-IV of the capacitor element illustrated in FIG. 3. FIG. 4 is a cross-sectional view illustrating a partially enlarged cross-sectional configuration of the capacitor element illustrated in FIG. 3. It is a flowchart for demonstrating the flow of the manufacturing process regarding the manufacturing method of an electrolytic capacitor. It is a figure showing the light absorption characteristic change of a conductive polymer (polyethylene dioxythiophene). It is a figure showing the light absorption characteristic change of a conductive polymer (polypyrrole).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conductive polymer, 1Z ... Conductive polymer precursor, 2 ... Base | substrate, 10 ... Capacitor element, 11 ... Anode, 12 ... Dielectric layer, 12H ... Fine pore, 13 ... Solid electrolyte layer, 14 ... Cathode, 14A ... carbon layer, 14B ... silver layer.

Claims (10)

A step of generating a conductive polymer precursor so as to include the dopant by adding a dopant to the monomer and polymerizing;
A method of forming a conductive polymer by irradiating the conductive polymer precursor with an electromagnetic wave to form a conductive polymer. The method for forming a conductive polymer according to claim 1, wherein the conductive polymer precursor is irradiated with ultraviolet rays as the electromagnetic wave. The method for forming a conductive polymer according to claim 2, wherein ultraviolet rays having a wavelength of 400 nm or less are used. The irradiation intensity of ultraviolet light as well as in the range of 1 mW / cm ² or more 300 mW / cm ² or less, the integrated quantity of light, characterized in that in the range of 100 mJ / cm ² or more 50000mJ / cm ² or less claim 2, wherein Item 4. A method for forming a conductive polymer according to Item 3. The conductive polymer precursor according to any one of claims 1 to 4, wherein the conductive polymer precursor is generated by oxidative polymerization of the monomer using an oxidant. Molecular formation method. The method for forming a conductive polymer according to any one of claims 1 to 5, wherein the conductive polymer is formed on a predetermined substrate. 7. The method according to claim 1, wherein at least one member selected from the group comprising polyaniline, polypyrrole, polythiophene, polyfuran and derivatives thereof is generated as the conductive polymer precursor. The formation method of the conductive polymer of description. 8. The method according to claim 1, wherein at least one member selected from the group comprising alkylbenzene sulfonic acid and a salt thereof, alkylnaphthalene sulfonic acid and a salt thereof, and phosphoric acid is used as the dopant. The method for forming a conductive polymer according to Item. A method of manufacturing an electrolytic capacitor having a solid electrolyte layer,
Forming the solid electrolyte layer comprises:
A step of generating a conductive polymer precursor so as to include the dopant by adding a dopant to the monomer and polymerizing;
Forming a solid electrolyte layer so as to include the conductive polymer by irradiating the conductive polymer precursor with electromagnetic waves to form the conductive polymer. Production method. The method for producing an electrolytic capacitor according to claim 9, wherein the conductive polymer precursor is irradiated with ultraviolet rays as the electromagnetic wave.

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