WO2016136804A1 - Electrode material for aluminum electrolytic capacitors and method for producing same - Google Patents

Electrode material for aluminum electrolytic capacitors and method for producing same Download PDF

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Publication number
WO2016136804A1
WO2016136804A1 PCT/JP2016/055418 JP2016055418W WO2016136804A1 WO 2016136804 A1 WO2016136804 A1 WO 2016136804A1 JP 2016055418 W JP2016055418 W JP 2016055418W WO 2016136804 A1 WO2016136804 A1 WO 2016136804A1
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WIPO (PCT)
Prior art keywords
aluminum
electrode material
sintered body
powder
aluminum electrolytic
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PCT/JP2016/055418
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French (fr)
Japanese (ja)
Inventor
敏文 平
賢治 村松
健太 石神
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東洋アルミニウム株式会社
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Priority to JP2017502422A priority Critical patent/JP6629288B2/en
Publication of WO2016136804A1 publication Critical patent/WO2016136804A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/04—Electrodes or formation of dielectric layers thereon
    • H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
    • H01G9/055—Etched foil electrodes

Definitions

  • the present invention relates to an electrode material used for an aluminum electrolytic capacitor, particularly to an anode electrode material used for an aluminum electrolytic capacitor and a method for producing the same.
  • an aluminum foil is used as an electrode material for an aluminum electrolytic capacitor. Etching pits are formed by etching the aluminum foil, and the surface area of the aluminum foil can be increased. In addition, an anodized film is formed by anodizing the surface of the aluminum foil, and this functions as a dielectric. Therefore, various types of aluminum anode electrode materials (foil) for electrolytic capacitors are manufactured according to applications by etching the aluminum foil and forming oxide films on the surface with various voltages according to the operating voltage. be able to.
  • Patent Document 1 a film made of a composition containing at least one powder of aluminum and an aluminum alloy is formed on a base material, and the film is sintered to obtain a conventional aluminum foil having an increased surface area.
  • An alternative method for obtaining a sintered body having a large surface area has been proposed. According to this method, it has also been confirmed that a surface area larger than the pit area obtained by the etching process can be obtained.
  • the present invention has been made in view of the above-described problems, and does not require an etching process, and can reduce breakage during anodizing, and a high-capacity electrode material for an aluminum electrolytic capacitor and a method for manufacturing the same The purpose is to provide.
  • the present inventors formed a sintered body of at least one powder of aluminum and aluminum alloy on the aluminum foil base material, and further embossed and sintered. It has been found that the above object can be achieved by adjusting the surface roughness of the bonded body within a predetermined range, and the present invention has been completed. That is, this invention relates to the following electrode materials for aluminum electrolytic capacitors, and its manufacturing method. In addition, in this invention, when it has a sintered compact on both surfaces of an aluminum foil base material, "the total thickness of a sintered compact" means the sum total of the thickness of the sintered compact formed in both surfaces. Item 1.
  • An electrode material for an aluminum electrolytic capacitor having a sintered body of at least one powder of aluminum and an aluminum alloy on one side or both sides of an aluminum foil base material, and at least one side of the sintered body being a sintered body
  • An electrode material for an aluminum electrolytic capacitor comprising a surface having an arithmetic average roughness (Ra) of 0.7 to 3.5 ⁇ m.
  • Item 2. The electrode material for an aluminum electrolytic capacitor according to Item 1, wherein the total thickness of the sintered body is 15 to 300 ⁇ m.
  • a method for producing an electrode material for an aluminum electrolytic capacitor comprising: A first step of laminating a film made of a composition comprising at least one powder of aluminum and an aluminum alloy on one or both surfaces of an aluminum foil base; A second step of obtaining a sintered body by sintering the film; And a third step of embossing at least one surface of the sintered body so as to include a region having an arithmetic average roughness (Ra) of 0.7 to 3.5 ⁇ m.
  • Ra arithmetic average roughness
  • Electrode Material for Aluminum Electrolytic Capacitor is an electrode material for aluminum electrolytic capacitor, and is made of aluminum.
  • the foil base material has a sintered body of at least one kind of powder of aluminum and aluminum alloy on one or both sides of the foil base material, and Ra is 0.7 to 3.5 ⁇ m on the surface of at least one side of the sintered body. A region is included. Ra is based on JIS B0601-2001. Moreover, 0.7 to 3.5 ⁇ m means 0.7 ⁇ m or more and 3.5 ⁇ m or less, and the same applies to other numerical ranges indicated by “to”. Hereinafter, each structure of the electrode material will be described.
  • the raw material aluminum powder for example, aluminum powder having an aluminum purity of 99.8% by weight or more is preferable.
  • the raw material aluminum alloy powder include silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), and titanium (Ti ), Vanadium (V), gallium (Ga), nickel (Ni), boron (B), zirconium (Zr) and the like, an alloy containing one or more of them is preferable.
  • the content of these elements in the aluminum alloy is preferably 100 ppm by weight or less, particularly 50 ppm by weight or less.
  • an average particle diameter D 50 before sintering of 1.5 to 9.5 ⁇ m is preferably used. It can be suitably used an average particle size D 50 as an electrode material for aluminum electrolytic capacitors, especially medium and high capacity by this range. If the average particle size D 50 is less than 1.5 ⁇ m, the strength of the sintered body is low, and there is a risk of damage during the process or during handling. Further, if the average particle diameter D 50 exceeds 9.5 ⁇ m, there is a possibility that sufficient capacity cannot be obtained when used as an electrode material for electrolytic capacitors.
  • the average particle diameter in the present specification is a D 50 value obtained by measuring the particle size distribution on a volume basis by a laser diffraction method.
  • the average particle diameter of the powder after sintering is measured by observing the cross section of the sintered body with a scanning electron microscope.
  • the maximum diameter (major axis) of each particle having a substantially circular shape is the particle diameter of the particle, the particle diameter of any 50 particles is measured, and the arithmetic average of these particles is sintered.
  • required above and the average particle diameter after sintering are substantially the same.
  • membrane performed after sintering is also substantially the same.
  • the shape of the powder is not particularly limited, and any of a spherical shape, an indefinite shape, a scale shape, a fiber shape, and the like can be suitably used, but a powder made of spherical particles is particularly preferable.
  • the powder produced by a known method can be used.
  • an atomizing method, a melt spinning method, a rotating disk method, a rotating electrode method, a rapid solidification method, and the like can be mentioned.
  • the atomizing method, particularly the gas atomizing method is preferable. That is, it is desirable to use a powder obtained by atomizing a molten metal.
  • the sintered body is preferably one in which the powders are sintered while maintaining a gap between them. Specifically, it is preferable that the powders are connected by sintering while maintaining voids and have a three-dimensional network structure. Thus, by setting it as a porous sintered compact, it becomes possible to obtain a desired electrostatic capacitance, without performing an etching process.
  • the porosity of the sintered body is not particularly limited, but is preferably 40 to 55% by volume, and particularly preferably 45 to 50% by volume. The porosity in this specification is a value calculated from thickness and weight.
  • the sintered body is formed on one side or both sides of the aluminum foil base material.
  • the total thickness of the sintered body after the embossing is preferably 15 to 300 ⁇ m, more preferably 80 to 150 ⁇ m.
  • the sintered body on both surfaces it is preferable to arrange the sintered body symmetrically across the substrate.
  • the total thickness of the sintered body formed on both surfaces after embossing is preferably 15 to 300 ⁇ m, and more preferably 80 to 150 ⁇ m.
  • the thickness of the single-sided sintered compact is 1/3 or more of the total thickness including the thickness of the aluminum foil base material.
  • the average thickness of the sintered body is the same as the thickness of the aluminum foil base material after embossing. Therefore, measure 7 points with a micrometer and calculate the aluminum foil base from the average value of 5 points excluding the maximum and minimum values. It is obtained as a value obtained by subtracting the material thickness.
  • the embossing is preferably performed in an area ratio of 70% or more with respect to one surface of the aluminum foil base material, 80% More preferably, it is applied to the above region.
  • the upper limit of the area ratio is not limited, but can be set to 100% or less, 90% or less, and the like.
  • an aluminum foil is used as a base material for forming the sintered body. And before forming the said sintered compact, you may roughen the surface of an aluminum foil base material previously.
  • the surface roughening method is not particularly limited, and known techniques such as cleaning, etching, blasting and the like can be used.
  • the aluminum foil as the substrate is not particularly limited, and pure aluminum or aluminum alloy can be used.
  • the aluminum foil used in the present invention is composed of silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (
  • An aluminum alloy to which at least one alloy element of Ti), vanadium (V), gallium (Ga), nickel (Ni) and boron (B) is added within a necessary range may be included, and the above elements are included as inevitable impurity elements.
  • Aluminum may be used.
  • the thickness of the aluminum foil base material is not particularly limited, but is preferably 5 ⁇ m or more and 100 ⁇ m or less, and particularly preferably 15 ⁇ m or more and 50 ⁇ m or less.
  • the above aluminum foil can be manufactured by a known method. For example, a molten aluminum or aluminum alloy having the above predetermined composition is prepared, and an ingot obtained by casting the molten metal is appropriately homogenized. Thereafter, an aluminum foil can be obtained by subjecting the ingot to hot rolling and cold rolling.
  • an intermediate annealing treatment may be performed in the range of 50 to 500 ° C., particularly 150 to 400 ° C.
  • a soft foil may be obtained by performing an annealing treatment within a range of 150 to 650 ° C., particularly 350 to 550 ° C.
  • the electrode material of the present invention can be used for any aluminum electrolytic capacitor for low pressure, medium pressure or high pressure. It is particularly suitable as an intermediate or high pressure (medium / high pressure) aluminum electrolytic capacitor.
  • the electrode material of the present invention when used as an electrode for an aluminum electrolytic capacitor, the electrode material can be used without etching treatment. That is, the electrode material of the present invention can be used as an electrode or an electrode foil as it is or without an etching treatment, or by anodizing treatment.
  • an anode foil using the electrode material of the present invention and a cathode foil are laminated with a separator interposed therebetween, and wound to form a capacitor element.
  • This capacitor element is used as an electrolyte.
  • An electrolytic capacitor is obtained by impregnating, housing a capacitor element containing an electrolytic solution in an exterior case, and sealing the case with a sealing body.
  • the method for producing the aluminum electrolytic capacitor electrode material of the present invention is not limited, but a film comprising a composition containing at least one powder of aluminum and aluminum alloy is used.
  • a first step of laminating on one or both sides of an aluminum foil substrate, a second step of obtaining a sintered body by sintering the coating, and at least one of the sintered bodies on the surface of the sintered body A manufacturing method including a third step of embossing so as to include a region having an arithmetic average roughness (Ra) of 0.7 to 3.5 ⁇ m can be employed.
  • a film made of a composition containing at least one powder of aluminum and an aluminum alloy is laminated on one side or both sides of an aluminum foil substrate.
  • the powder preferably has an average particle diameter D 50 before sintering of 1.5 to 9.5 ⁇ m.
  • membrane is formed in the single side
  • composition (component) of aluminum and aluminum alloy those mentioned above can be used.
  • powder for example, a pure aluminum powder having an aluminum purity of 99.8% by weight or more is preferably used.
  • aluminum foil base material what was mentioned above can also be used as an aluminum foil base material.
  • the composition may contain a binder, a solvent, a sintering aid, a surfactant and the like as necessary. Any of these may be known or commercially available.
  • the binder is not limited, for example, carboxy-modified polyolefin resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride copolymer resin, vinyl alcohol resin, butyral resin, vinyl fluoride resin, acrylic resin, polyester resin, urethane resin,
  • a synthetic resin such as an epoxy resin, a urea resin, a phenol resin, an acrylonitrile resin, a cellulose resin, a paraffin wax, or a polyethylene wax, and a natural resin or wax such as wax, tar, glue, urushi, pine resin, or beeswax can be suitably used.
  • binders are classified into those that volatilize when heated depending on the molecular weight, the type of resin, etc., and those that remain together with the aluminum powder due to thermal decomposition, and are selectively used according to the desired electrical characteristics such as capacitance. be able to.
  • solvents can be used.
  • organic solvents such as ethanol, toluene, ketones, and esters can be used.
  • the film can be formed by a known printing method such as silk screen printing in addition to forming the paste composition using, for example, a roller, brush, spray, dipping or the like.
  • the coating is formed on one side or both sides of the aluminum foil substrate.
  • the total thickness of the coating is preferably 15 to 300 ⁇ m, more preferably 80 to 150 ⁇ m in total thickness of the sintered body finally obtained through sintering and embossing.
  • the film When forming on both surfaces, it is preferable to arrange the film symmetrically across the base material, and the total thickness of the sintered body formed on both surfaces finally obtained through sintering and embossing is 15 to 300 ⁇ m Is preferable, and 80 to 150 ⁇ m is more preferable.
  • membrane of one side is 1/3 or more of the whole thickness also including the thickness of an aluminum foil base material.
  • the average thickness of the film is obtained by measuring 7 points with a micrometer and subtracting the thickness of the aluminum foil base material from the average value of 5 points excluding the maximum and minimum values.
  • the film may be dried at a temperature in the range of 20 to 300 ° C. as necessary.
  • the film is sintered at a temperature of 560 to 660 ° C. to obtain a sintered body.
  • the sintering temperature is 560 to 660 ° C., preferably 570 to 650 ° C., more preferably 580 to 620 ° C.
  • the sintering time varies depending on the sintering temperature and the like, but can usually be appropriately determined within a range of about 5 to 24 hours.
  • the sintering atmosphere is not particularly limited, and may be any one of a vacuum atmosphere, an inert gas atmosphere, an oxidizing gas atmosphere (air), a reducing atmosphere, etc., and particularly a vacuum atmosphere or a reducing atmosphere. Is preferred.
  • the pressure condition may be normal pressure, reduced pressure or increased pressure. If the sintering temperature is lower than 560 ° C., the powder does not sinter and the strength of the sintered body is weakened and may break. If it exceeds 660 ° C, the powder may melt, and there is a possibility that sufficient capacity cannot be obtained when used as an electrode material for electrolytic capacitors.
  • the heat treatment atmosphere is not particularly limited, and may be any of a vacuum atmosphere, an inert gas atmosphere, or an oxidizing gas atmosphere, for example.
  • the pressure condition may be normal pressure, reduced pressure, or increased pressure.
  • embossing is performed so that at least one surface of the sintered body of the sintered body includes a region where Ra is 0.7 to 3.5 ⁇ m on the surface of the sintered body.
  • Ra of the film immediately after sintering is about 0.2 to 0.5 ⁇ m, so that the film surface can be roughened by embossing.
  • the embossing method is not particularly limited, but a method using an embossing roll (rotary die-setting roll) is preferable.
  • the unevenness of the embossing roll surface can be adjusted within a predetermined range so that Ra of the sintered film is 0.7 to 3.5 ⁇ m. If Ra of the sintered film is less than 0.7 ⁇ m, the effect of the present invention is poor, and if it exceeds 3.5 ⁇ m, the sintered body may crack.
  • the embossing is preferably performed in an area ratio of 70% or more with respect to one surface of the aluminum foil base material, 80% More preferably, it is applied to the above region.
  • the upper limit of the area ratio is not limited, but can be set to 100% or less, 90% or less, and the like.
  • the electrode material of the present invention can be obtained without performing an etching treatment.
  • the electrode material of the present invention can be formed by applying a anodic oxidation treatment as a fourth step to form a dielectric and coating an anodized film.
  • the anodizing conditions are not particularly limited, but a current of 10 mA / cm 2 or more and 400 mA / cm 2 or less is usually 5 in a boric acid solution having a concentration of 0.01 mol to 5 mol and a temperature of 30 ° C. to 100 ° C. It may be applied for more than a minute.
  • Example 100 parts by weight of an aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ58FN) having an average particle diameter D 50 of 1.5 to 9.5 ⁇ m is added to 60 parts by weight of an ethyl cellulose binder (7% by weight is resin content, 93% by weight) % Was mixed with a solvent (butyl acetate) to obtain a coating solution.
  • an aluminum powder JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ58FN
  • the above coating solution was applied to both sides of an aluminum foil (width 500 mm x length 1000 mm) with a thickness of 15 to 50 ⁇ m using a comma coater and dried.
  • the sintered body was prepared by degreasing in air at 350 ° C. and sintering in an argon gas atmosphere at a temperature of 620 ° C. for 10 hours.
  • the electrode material of this invention was produced by embossing a sintered compact using a rotary type
  • Comparative Example A comparative example was prepared in the same manner as in Example except that embossing was not performed.
  • each electrode material that is, the total thickness of the sintered body after embossing and the arithmetic average surface roughness (Ra) are shown in Tables 1 to 3. About a comparative example, it is not Ra but the thickness of a sintered compact is shown.
  • Test example 1 Each electrode material was anodized at a predetermined voltage in an anodizing line.
  • the anodic oxidation voltage of the treatment was set at three levels of 200V, 400V and 600V, and was carried out in an aqueous boric acid solution (50 g / L). Those that passed without breaking at all three levels were accepted, and those that broke even at one level were rejected. The obtained results are shown in Tables 1 to 3. In each table, pass and fail are indicated by ⁇ and ⁇ , respectively.
  • Test example 2 It is an electrode material using powder with an average particle diameter D 50 of 3 ⁇ m.
  • a sintered layer (total thickness 120 ⁇ m after embossing) is laminated on both sides of 50 ⁇ m aluminum foil, and Ra on one side is 1.5 by embossing.
  • the capacity of the laminated foil having a thickness of ⁇ m was compared with the capacity of an etched foil in which both sides of the 50 ⁇ m aluminum foil were etched and the sintered layer was not laminated. The results are shown in Table 4.
  • the laminated foil shows a superior capacitance value ( ⁇ F / cm 2 ) in any anodic oxidation voltage region as compared with the etched foil.

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  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
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Abstract

The present invention provides: an electrode material for high-capacity aluminum electrolytic capacitors, which does not require etching and is capable of reducing the occurrence of breakage during anodic oxidation; and a method for producing this electrode material for high-capacity aluminum electrolytic capacitors. The present invention specifically provides an electrode material for aluminum electrolytic capacitors, which is characterized in that: one surface or both surfaces of an aluminum foil base are provided with sintered bodies of an aluminum powder and/or an aluminum alloy powder; and at least one of the sintered bodies, namely at least a sintered body on one surface comprises a region having an arithmetic mean roughness (Ra) of 0.7-3.5 μm in the surface.

Description

アルミニウム電解コンデンサ用電極材及びその製造方法Electrode material for aluminum electrolytic capacitor and method for producing the same
　本発明は、アルミニウム電解コンデンサに用いられる電極材、特にアルミニウム電解コンデンサに用いられる陽極用電極材及びその製造方法に関する。 The present invention relates to an electrode material used for an aluminum electrolytic capacitor, particularly to an anode electrode material used for an aluminum electrolytic capacitor and a method for producing the same.
　一般に、アルミニウム電解コンデンサの電極材にはアルミニウム箔が使用されており、このアルミニウム箔に、エッチング処理を施すことによってエッチングピットが形成され、その表面積を増大することができる。また、アルミニウム箔の表面に陽極酸化処理を施すことにより、酸化皮膜が形成され、これが誘電体として機能する。このため、アルミニウム箔をエッチング処理し、その表面に使用電圧に応じた種々の電圧で酸化皮膜を形成することにより、用途に応じた各種の電解コンデンサ用アルミニウム陽極用電極材（箔）を製造することができる。 Generally, an aluminum foil is used as an electrode material for an aluminum electrolytic capacitor. Etching pits are formed by etching the aluminum foil, and the surface area of the aluminum foil can be increased. In addition, an anodized film is formed by anodizing the surface of the aluminum foil, and this functions as a dielectric. Therefore, various types of aluminum anode electrode materials (foil) for electrolytic capacitors are manufactured according to applications by etching the aluminum foil and forming oxide films on the surface with various voltages according to the operating voltage. be able to.
　しかしながら、エッチング処理では、塩酸中に硫酸、燐酸、硝酸等を含有する塩酸水溶液を使用しなければならず、塩酸は環境面での大きな負荷となり、その処理も工程上又は経済上の負担になる。また、エッチング処理では、エッチングピットの発生が均一にならないことがあり、ピットの合体が起こり易い領域やピットの発生が起こり難い領域が生じたりし、いわゆるピット規制に関して課題がある。また、微細ピットを多数発生させると電極材の強度が弱くなるという問題もある。 However, in the etching process, an aqueous hydrochloric acid solution containing sulfuric acid, phosphoric acid, nitric acid, etc. must be used in hydrochloric acid, and hydrochloric acid is a large environmental burden, and the process also imposes a burden on the process and economy. . Further, in the etching process, the generation of etching pits may not be uniform, and an area where pit coalescence is likely to occur or an area where pits are unlikely to occur is generated. Another problem is that if a large number of fine pits are generated, the strength of the electrode material becomes weak.
　そのため、近年、エッチング処理によらずにアルミニウム箔の表面積を増大する方法の開発が望まれている。例えば、特許文献１には、アルミニウム及びアルミニウム合金の少なくとも１種の粉末を含む組成物からなる皮膜を基材に形成し、前記皮膜を焼結させることにより、従来の表面積の拡大したアルミニウム箔に代わる表面積の大きな焼結体を得るための方法が提案されている。この方法によれば、エッチング処理により得られるピット面積以上の表面積が得られることも確認されている。 Therefore, in recent years, it has been desired to develop a method for increasing the surface area of the aluminum foil without depending on the etching process. For example, in Patent Document 1, a film made of a composition containing at least one powder of aluminum and an aluminum alloy is formed on a base material, and the film is sintered to obtain a conventional aluminum foil having an increased surface area. An alternative method for obtaining a sintered body having a large surface area has been proposed. According to this method, it has also been confirmed that a surface area larger than the pit area obtained by the etching process can be obtained.
　ところが、本発明者らが特許文献１に記載のアルミニウム電解コンデンサ用電極箔を製造ライン下において陽極酸化処理を試みたところ、このアルミニウム電解コンデンサ用電極箔が破断してしまうという問題があった。 However, when the inventors tried anodizing the electrode foil for aluminum electrolytic capacitors described in Patent Document 1 under the production line, there was a problem that the electrode foil for aluminum electrolytic capacitors was broken.
　特に、アルミニウム箔基材（基材としてのアルミニウム箔）表面に形成される焼結体に含まれるアルミニウム及びアルミニウム合金の少なくとも１種の粉末の粒子径が細かいほど表面積は増大し、アルミニウム電解コンデンサとして用いた際の静電容量の向上に寄与することができるが、粒子径が細かいほど破断しやすいことが判明した。すなわち、アルミニウム箔表面にアルミニウム及びアルミニウム合金の少なくとも１種の粉末を積層して焼結させた焼結体において、高容量のアルミニウム電解コンデンサ用電極箔を製造ライン下において陽極酸化処理することが困難であった。 In particular, as the particle diameter of at least one powder of aluminum and aluminum alloy contained in a sintered body formed on the surface of an aluminum foil base material (aluminum foil as a base material) becomes finer, the surface area increases, and as an aluminum electrolytic capacitor Although it can contribute to the improvement of the electrostatic capacity when used, it has been found that the finer the particle diameter, the easier it is to break. That is, it is difficult to anodize a high-capacity aluminum electrolytic capacitor foil under the production line in a sintered body obtained by laminating and sintering at least one powder of aluminum and an aluminum alloy on the surface of the aluminum foil. Met.
特開2008-98279号公報JP 2008-98279 A
　本発明は、上述した課題に鑑みてなされたものであり、エッチング処理が不要で、且つ、陽極酸化処理時の破断を低減することのできる、高容量のアルミニウム電解コンデンサ用電極材及びその製造方法を提供することを目的とする。 The present invention has been made in view of the above-described problems, and does not require an etching process, and can reduce breakage during anodizing, and a high-capacity electrode material for an aluminum electrolytic capacitor and a method for manufacturing the same The purpose is to provide.
　本発明者らは、上記目的を達成すべく鋭意研究を進めた結果、アルミニウム及びアルミニウム合金の少なくとも１種の粉末の焼結体をアルミニウム箔基材上に形成し、さらにエンボス加工を施して焼結体の表面粗度を所定内に調整することにより上記目的を達成できることを見出し、本発明を完成するに至った。
　すなわち、本発明は、以下のアルミニウム電解コンデンサ用電極材及びその製造方法に関する。なお、本発明において、アルミニウム箔基材の両面に焼結体を有する場合、「焼結体の総厚み」とは両面に形成された焼結体の厚みの合計を意味する。
項１．アルミニウム電解コンデンサ用電極材であって、アルミニウム箔基材の片面又は両面にアルミニウム及びアルミニウム合金の少なくとも1種の粉末の焼結体を有し、前記焼結体のうち、少なくとも片面の焼結体の表面に算術平均粗さ（Ra）が0.7～3.5μmである領域を含むことを特徴とするアルミニウム電解コンデンサ用電極材。
項２．前記焼結体の総厚みが15～300μmである、項１に記載のアルミニウム電解コンデンサ用電極材。
項３．前記粉末の平均粒径が1.5～9.5μmである、項１又は２に記載のアルミニウム電解コンデンサ用電極材。
項４．前記アルミニウム箔基材の厚さが5～100μmである、項１～３のいずれかに記載のアルミニウム電解コンデンサ用電極材。
項５．前記焼結体の表面に、さらに陽極酸化皮膜を有する、項１～４のいずれかに記載のアルミニウム電解コンデンサ用電極材。
項６．アルミニウム電解コンデンサ用電極材を製造する方法であって、
アルミニウム及びアルミニウム合金の少なくとも1種の粉末を含む組成物からなる皮膜をアルミニウム箔基材の片面又は両面に積層する第1工程と、
前記皮膜を焼結することにより焼結体を得る第2工程と、
前記焼結体のうち、少なくとも片面の焼結体の表面に算術平均粗さ（Ra）が0.7～3.5μmである領域を含むようにエンボス加工を施す第3工程とを含む製造方法。
項７．エッチング工程を含まない、項６に記載の製造方法。 As a result of diligent research to achieve the above object, the present inventors formed a sintered body of at least one powder of aluminum and aluminum alloy on the aluminum foil base material, and further embossed and sintered. It has been found that the above object can be achieved by adjusting the surface roughness of the bonded body within a predetermined range, and the present invention has been completed.
That is, this invention relates to the following electrode materials for aluminum electrolytic capacitors, and its manufacturing method. In addition, in this invention, when it has a sintered compact on both surfaces of an aluminum foil base material, "the total thickness of a sintered compact" means the sum total of the thickness of the sintered compact formed in both surfaces.
Item 1. An electrode material for an aluminum electrolytic capacitor having a sintered body of at least one powder of aluminum and an aluminum alloy on one side or both sides of an aluminum foil base material, and at least one side of the sintered body being a sintered body An electrode material for an aluminum electrolytic capacitor comprising a surface having an arithmetic average roughness (Ra) of 0.7 to 3.5 μm.
Item 2. Item 2. The electrode material for an aluminum electrolytic capacitor according to Item 1, wherein the total thickness of the sintered body is 15 to 300 µm.
Item 3. Item 3. The electrode material for an aluminum electrolytic capacitor according to Item 1 or 2, wherein the powder has an average particle size of 1.5 to 9.5 μm.
Item 4. Item 4. The electrode material for an aluminum electrolytic capacitor according to any one of Items 1 to 3, wherein the aluminum foil base material has a thickness of 5 to 100 μm.
Item 5. Item 5. The electrode material for an aluminum electrolytic capacitor according to any one of Items 1 to 4, further comprising an anodized film on the surface of the sintered body.
Item 6. A method for producing an electrode material for an aluminum electrolytic capacitor, comprising:
A first step of laminating a film made of a composition comprising at least one powder of aluminum and an aluminum alloy on one or both surfaces of an aluminum foil base;
A second step of obtaining a sintered body by sintering the film;
And a third step of embossing at least one surface of the sintered body so as to include a region having an arithmetic average roughness (Ra) of 0.7 to 3.5 μm.
Item 7. Item 7. The manufacturing method according to Item 6, which does not include an etching step.
　本発明によれば、アルミニウム電解コンデンサ用電極材であって、エッチング処理が不要であり、且つ、陽極酸化処理時の破断を低減することのできる、高容量のアルミニウム電解コンデンサ用電極材及びその製造方法が提供される。 ADVANTAGE OF THE INVENTION According to this invention, it is an electrode material for aluminum electrolytic capacitors, an etching process is unnecessary, and the electrode material for aluminum electrolytic capacitors with high capacity | capacitance which can reduce the fracture | rupture at the time of an anodizing process, and its manufacture A method is provided.
　（１）アルミニウム電解コンデンサ用電極材
　本発明のアルミニウム電解コンデンサ用電極材（本願明細書において、単に「電極材」と表現することがある。）は、アルミニウム電解コンデンサ用電極材であって、アルミニウム箔基材の片面又は両面にアルミニウム及びアルミニウム合金の少なくとも1種の粉末の焼結体を有し、前記焼結体のうち、少なくとも片面の焼結体の表面にRaが0.7～3.5μmである領域を含むことを特徴とする。なお、RaはJIS　B0601-2001年に基づく。また、0.7～3.5μmは、0.7μm以上3.5μm以下を意味し、「～」で示す他の数値範囲も同様である。
　以下、電極材の各構成について説明する。 (1) Electrode Material for Aluminum Electrolytic Capacitor The electrode material for aluminum electrolytic capacitor of the present invention (sometimes simply referred to as “electrode material” in the present specification) is an electrode material for aluminum electrolytic capacitor, and is made of aluminum. The foil base material has a sintered body of at least one kind of powder of aluminum and aluminum alloy on one or both sides of the foil base material, and Ra is 0.7 to 3.5 μm on the surface of at least one side of the sintered body. A region is included. Ra is based on JIS B0601-2001. Moreover, 0.7 to 3.5 μm means 0.7 μm or more and 3.5 μm or less, and the same applies to other numerical ranges indicated by “to”.
Hereinafter, each structure of the electrode material will be described.
　原料のアルミニウム粉末としては、例えば、アルミニウム純度99.8重量％以上のアルミニウム粉末が好ましい。また、原料のアルミニウム合金粉末としては、例えば、珪素（Si）、鉄（Fe）、銅（Cu）、マンガン（Mn）、マグネシウム（Mg）、クロム（Cr）、亜鉛（Zn）、チタン（Ti）、バナジウム（V）、ガリウム（Ga）、ニッケル（Ni）、ホウ素（B）、ジルコニウム（Zr）等の元素のうち、1種又は2種以上を含む合金が好ましい。アルミニウム合金中のこれらの元素の含有量は、100重量ppm以下、特に50重量ppm以下とすることが好ましい。 As the raw material aluminum powder, for example, aluminum powder having an aluminum purity of 99.8% by weight or more is preferable. Examples of the raw material aluminum alloy powder include silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), and titanium (Ti ), Vanadium (V), gallium (Ga), nickel (Ni), boron (B), zirconium (Zr) and the like, an alloy containing one or more of them is preferable. The content of these elements in the aluminum alloy is preferably 100 ppm by weight or less, particularly 50 ppm by weight or less.
　前記粉末としては、焼結前の平均粒径D50が1.5～9.5μmのものを用いるのが好ましい。平均粒径D50をこの範囲とすることで特に中高容量のアルミニウム電解コンデンサの電極材として好適に利用することができる。平均粒径D50が1.5μm未満では焼結体の強度が低くなり、工程中やハンドリング時に破損するおそれがある。また、平均粒径D50が9.5μm超過では電解コンデンサの電極材として使用した場合に十分な容量が得られないおそれがある。 As the powder, one having an average particle diameter D 50 before sintering of 1.5 to 9.5 μm is preferably used. It can be suitably used an average particle size D 50 as an electrode material for aluminum electrolytic capacitors, especially medium and high capacity by this range. If the average particle size D 50 is less than 1.5 μm, the strength of the sintered body is low, and there is a risk of damage during the process or during handling. Further, if the average particle diameter D 50 exceeds 9.5 μm, there is a possibility that sufficient capacity cannot be obtained when used as an electrode material for electrolytic capacitors.
　なお、本明細書における平均粒径は、レーザー回折法により粒度分布を体積基準で測定して求めたD50値である。但し、焼結後の前記粉末の平均粒径は、前記焼結体の断面を、走査型電子顕微鏡によって観察することによって測定する。例えば、焼結後の前記粉末は、一部が溶融又は粉末同士が繋がった状態となっているが、略円形状を有する部分は近似的に粒子とみなすことができる。そこで、上記断面観察において、略円形状を有する粒子のそれぞれの最大径（長径）をその粒子の粒径とし、任意の50個の粒子の粒径を測定し、これらの算術平均を焼結後の前記粉末の平均粒径とする。なお、上記で求められる焼結前の平均粒径と焼結後の平均粒径はほぼ同じである。また、焼結後に行う皮膜のエンボス加工の前後における平均粒径も実質的に同じである。 The average particle diameter in the present specification is a D 50 value obtained by measuring the particle size distribution on a volume basis by a laser diffraction method. However, the average particle diameter of the powder after sintering is measured by observing the cross section of the sintered body with a scanning electron microscope. For example, although the powder after sintering is in a state where a part thereof is melted or the powders are connected to each other, a portion having a substantially circular shape can be regarded as an approximate particle. Therefore, in the cross-sectional observation, the maximum diameter (major axis) of each particle having a substantially circular shape is the particle diameter of the particle, the particle diameter of any 50 particles is measured, and the arithmetic average of these particles is sintered. The average particle size of the powder. In addition, the average particle diameter before sintering calculated | required above and the average particle diameter after sintering are substantially the same. Moreover, the average particle diameter before and after embossing of the film | membrane performed after sintering is also substantially the same.
　前記粉末の形状は、特に限定されず、球状、不定形状、鱗片状、繊維状等のいずれも好適に使用できるが、球状粒子からなる粉末が特に好ましい。 The shape of the powder is not particularly limited, and any of a spherical shape, an indefinite shape, a scale shape, a fiber shape, and the like can be suitably used, but a powder made of spherical particles is particularly preferable.
　前記粉末は、公知の方法によって製造されるものを使用することができる。例えば、アトマイズ法、メルトスピニング法、回転円盤法、回転電極法、急冷凝固法等が挙げられるが、工業的生産にはアトマイズ法、特にガスアトマイズ法が好ましい。すなわち、溶湯をアトマイズすることにより得られる粉末を用いることが望ましい。 The powder produced by a known method can be used. For example, an atomizing method, a melt spinning method, a rotating disk method, a rotating electrode method, a rapid solidification method, and the like can be mentioned. For industrial production, the atomizing method, particularly the gas atomizing method is preferable. That is, it is desirable to use a powder obtained by atomizing a molten metal.
　焼結体は、前記粉末どうしが互いに空隙を維持しながら焼結したものであることが好ましい。具体的には、各粉末どうしが空隙を維持しながら焼結によって繋がり、三次元網目構造を有していることが好ましい。このように多孔質焼結体とすることにより、エッチング処理を施さなくても、所望の静電容量を得ることが可能となる。焼結体の空孔率は特に制限されるものではないが、40～55体積％が好ましく、特に45～50体積％であることが好ましい。本明細書における空孔率は、厚みと重量より算出した値である。 The sintered body is preferably one in which the powders are sintered while maintaining a gap between them. Specifically, it is preferable that the powders are connected by sintering while maintaining voids and have a three-dimensional network structure. Thus, by setting it as a porous sintered compact, it becomes possible to obtain a desired electrostatic capacitance, without performing an etching process. The porosity of the sintered body is not particularly limited, but is preferably 40 to 55% by volume, and particularly preferably 45 to 50% by volume. The porosity in this specification is a value calculated from thickness and weight.
　焼結体はアルミニウム箔基材の片面又は両面に形成する。焼結体を片面に形成する場合は、エンボス加工後の焼結体の総厚みは15～300μmであることが好ましく、80～150μmであることがさらに好ましい。焼結体を両面に形成する場合には、基材を挟んで焼結体を対称に配置することが好ましい。エンボス加工後の両面に形成された焼結体の総厚みは15～300μmであることが好ましく、80～150μmであることがさらに好ましい。また、焼結体を両面に形成する場合、片面の焼結体の厚さはアルミニウム箔基材の厚さも含めた全体の厚みの1/3以上であることが好ましい。 The sintered body is formed on one side or both sides of the aluminum foil base material. When the sintered body is formed on one side, the total thickness of the sintered body after the embossing is preferably 15 to 300 μm, more preferably 80 to 150 μm. In the case of forming the sintered body on both surfaces, it is preferable to arrange the sintered body symmetrically across the substrate. The total thickness of the sintered body formed on both surfaces after embossing is preferably 15 to 300 μm, and more preferably 80 to 150 μm. Moreover, when forming a sintered compact on both surfaces, it is preferable that the thickness of the single-sided sintered compact is 1/3 or more of the total thickness including the thickness of the aluminum foil base material.
　なお、上記焼結体の平均厚みは、エンボス加工後もアルミニウム箔基材厚みは変わらないため、マイクロメーターで7点測定し、最大値と最小値を除いた5点の平均値からアルミニウム箔基材厚みを引いた値として求められる。また、陽極酸化処理時における破断等を回避できる効果を向上させるために、エンボス加工はアルミニウム箔基材の一面に対し、面積割合で70％以上の領域に施されていることが好ましく、80％以上の領域に施されていることがより好ましい。面積割合の上限は限定的ではないが、100％以下、90％以下等に設定することができる。 The average thickness of the sintered body is the same as the thickness of the aluminum foil base material after embossing. Therefore, measure 7 points with a micrometer and calculate the aluminum foil base from the average value of 5 points excluding the maximum and minimum values. It is obtained as a value obtained by subtracting the material thickness. Further, in order to improve the effect of avoiding breakage during anodizing treatment, the embossing is preferably performed in an area ratio of 70% or more with respect to one surface of the aluminum foil base material, 80% More preferably, it is applied to the above region. The upper limit of the area ratio is not limited, but can be set to 100% or less, 90% or less, and the like.
　本発明では、前記焼結体を形成する基材としてアルミニウム箔を用いる。そして、前記焼結体を形成するに先立って、予めアルミニウム箔基材の表面を粗面化しても良い。粗面化方法は、特に限定されず、洗浄、エッチング、ブラスト等の公知の技術を用いることができる。 In the present invention, an aluminum foil is used as a base material for forming the sintered body. And before forming the said sintered compact, you may roughen the surface of an aluminum foil base material previously. The surface roughening method is not particularly limited, and known techniques such as cleaning, etching, blasting and the like can be used.
　基材としてのアルミニウム箔は、特に限定されず、純アルミニウム又はアルミニウム合金を用いることができる。本発明で用いられるアルミニウム箔は、その組成として、珪素（Si）、鉄（Fe）、銅（Cu）、マンガン（Mn）、マグネシウム（Mg）、クロム（Cr）、亜鉛（Zn）、チタン（Ti）、バナジウム（V）、ガリウム（Ga）、ニッケル（Ni）及びホウ素（B）の少なくとも１種の合金元素を必要範囲内において添加したアルミニウム合金でもよく、上記元素を不可避的不純物元素として含むアルミニウムでもよい。 The aluminum foil as the substrate is not particularly limited, and pure aluminum or aluminum alloy can be used. The aluminum foil used in the present invention is composed of silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium ( An aluminum alloy to which at least one alloy element of Ti), vanadium (V), gallium (Ga), nickel (Ni) and boron (B) is added within a necessary range may be included, and the above elements are included as inevitable impurity elements. Aluminum may be used.
　アルミニウム箔基材の厚みは、特に限定されないが、5μm以上100μm以下であることが好ましく、15μm以上50μm以下であることが特に好ましい。 The thickness of the aluminum foil base material is not particularly limited, but is preferably 5 μm or more and 100 μm or less, and particularly preferably 15 μm or more and 50 μm or less.
　上記のアルミニウム箔は、公知の方法によって製造されるものを使用することができる。例えば、上記の所定の組成を有するアルミニウム又はアルミニウム合金の溶湯を調製し、これを鋳造して得られた鋳塊を適切に均質化処理する。その後、この鋳塊に熱間圧延と冷間圧延を施すことにより、アルミニウム箔を得ることができる。 The above aluminum foil can be manufactured by a known method. For example, a molten aluminum or aluminum alloy having the above predetermined composition is prepared, and an ingot obtained by casting the molten metal is appropriately homogenized. Thereafter, an aluminum foil can be obtained by subjecting the ingot to hot rolling and cold rolling.
　なお、上記の冷間圧延工程の途中で、50～500℃、特に150～400℃の範囲内で中間焼鈍処理を施しても良い。また、上記の冷間圧延工程の後に、150～650℃、特に350～550℃の範囲内で焼鈍処理を施して軟質箔としても良い。 In the middle of the cold rolling process, an intermediate annealing treatment may be performed in the range of 50 to 500 ° C., particularly 150 to 400 ° C. Further, after the cold rolling step, a soft foil may be obtained by performing an annealing treatment within a range of 150 to 650 ° C., particularly 350 to 550 ° C.
　本発明の電極材は、低圧用、中圧用又は高圧用のいずれのアルミニウム電解コンデンサにも使用することができる。特に中圧又は高圧用（中高圧用）アルミニウム電解コンデンサとして好適である。 The electrode material of the present invention can be used for any aluminum electrolytic capacitor for low pressure, medium pressure or high pressure. It is particularly suitable as an intermediate or high pressure (medium / high pressure) aluminum electrolytic capacitor.
　本発明の電極材は、アルミニウム電解コンデンサ用電極として使用するに当たり、当該電極材をエッチング処理せずに使用することができる。すなわち、本発明の電極材は、エッチング処理することなく、そのまま又は陽極酸化処理することにより電極又は電極箔として使用することができる。 When the electrode material of the present invention is used as an electrode for an aluminum electrolytic capacitor, the electrode material can be used without etching treatment. That is, the electrode material of the present invention can be used as an electrode or an electrode foil as it is or without an etching treatment, or by anodizing treatment.
　電解コンデンサの製造方法の一例としては、本発明の電極材を用いた陽極箔と、陰極箔とをセパレータを介在させて積層し、巻回してコンデンサ素子を形成し、このコンデンサ素子を電解液に含浸させ、電解液を含んだコンデンサ素子を外装ケースに収納し、封口体でケースを封口することによって電解コンデンサが得られる。 As an example of a method for manufacturing an electrolytic capacitor, an anode foil using the electrode material of the present invention and a cathode foil are laminated with a separator interposed therebetween, and wound to form a capacitor element. This capacitor element is used as an electrolyte. An electrolytic capacitor is obtained by impregnating, housing a capacitor element containing an electrolytic solution in an exterior case, and sealing the case with a sealing body.
　（２）アルミニウム電解コンデンサ用電極材の製造方法
　本発明のアルミニウム電解コンデンサ用電極材を製造する方法は限定的ではないが、アルミニウム及びアルミニウム合金の少なくとも1種の粉末を含む組成物からなる皮膜をアルミニウム箔基材の片面又は両面に積層する第1工程と、前記皮膜を焼結することにより焼結体を得る第2工程と、前記焼結体のうち、少なくとも片面の焼結体の表面に算術平均粗さ（Ra）が0.7～3.5μmである領域を含むようにエンボス加工を施す第3工程とを含む製造方法を採用することができる。 (2) Method for Producing Aluminum Electrolytic Capacitor Electrode Material The method for producing the aluminum electrolytic capacitor electrode material of the present invention is not limited, but a film comprising a composition containing at least one powder of aluminum and aluminum alloy is used. A first step of laminating on one or both sides of an aluminum foil substrate, a second step of obtaining a sintered body by sintering the coating, and at least one of the sintered bodies on the surface of the sintered body A manufacturing method including a third step of embossing so as to include a region having an arithmetic average roughness (Ra) of 0.7 to 3.5 μm can be employed.
　また、エッチング工程を含まない同様の製造方法を採用することができる。 Also, a similar manufacturing method that does not include an etching process can be employed.
　以下、上記製造方法を例に挙げて説明する。 Hereinafter, the manufacturing method will be described as an example.
　（第１工程）
　第１工程では、アルミニウム及びアルミニウム合金の少なくとも１種の粉末を含む組成物からなる皮膜をアルミニウム箔基材の片面又は両面に積層する。ここで、前記粉末は、焼結前の平均粒径D50が1.5～9.5μmとすることが好ましい。また、前記皮膜は前記アルミニウム箔基材の片面又は両面に形成されている。 (First step)
In the first step, a film made of a composition containing at least one powder of aluminum and an aluminum alloy is laminated on one side or both sides of an aluminum foil substrate. Here, the powder preferably has an average particle diameter D 50 before sintering of 1.5 to 9.5 μm. Moreover, the said film | membrane is formed in the single side | surface or both surfaces of the said aluminum foil base material.
　アルミニウム及びアルミニウム合金の組成（成分）としては、上記で挙げたものを用いることができる。前記粉末として、例えば、アルミニウム純度99.8重量％以上の純アルミニウム粉末を用いることが好ましい。また、アルミニウム箔基材としても、上記で挙げたものを用いることができる。 As the composition (component) of aluminum and aluminum alloy, those mentioned above can be used. As the powder, for example, a pure aluminum powder having an aluminum purity of 99.8% by weight or more is preferably used. Moreover, what was mentioned above can also be used as an aluminum foil base material.
　前記組成物は、必要に応じてバインダ、溶剤、焼結助剤、界面活性剤等が含まれていても良い。これらはいずれも公知又は市販のものを使用することができる。特に、本発明では、バインダ及び溶剤の少なくとも１種を含有させてペースト状組成物として用いることが好ましい。これにより効率よく皮膜を形成することができる。 The composition may contain a binder, a solvent, a sintering aid, a surfactant and the like as necessary. Any of these may be known or commercially available. In particular, in the present invention, it is preferable to use at least one of a binder and a solvent as a paste composition. Thereby, a film can be formed efficiently.
　バインダは限定的でなく、例えば、カルボキシ変性ポリオレフィン樹脂、酢酸ビニル樹脂、塩化ビニル樹脂、塩酢ビ共重合樹脂、ビニルアルコール樹脂、ブチラール樹脂、フッ化ビニル樹脂、アクリル樹脂、ポリエステル樹脂、ウレタン樹脂、エポキシ樹脂、尿素樹脂、フェノール樹脂、アクリロニトリル樹脂、セルロース樹脂、パラフィンワックス、ポリエチレンワックス等の合成樹脂、並びに、ワックス、タール、にかわ、ウルシ、松脂、ミツロウ等の天然樹脂又はワックスが好適に使用できる。これらのバインダは、分子量、樹脂の種類等により、加熱時に揮発するものと、熱分解によりその残渣がアルミニウム粉末とともに残存するものとがあり、所望の静電容量等の電気特性に応じて使い分けすることができる。 The binder is not limited, for example, carboxy-modified polyolefin resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride copolymer resin, vinyl alcohol resin, butyral resin, vinyl fluoride resin, acrylic resin, polyester resin, urethane resin, A synthetic resin such as an epoxy resin, a urea resin, a phenol resin, an acrylonitrile resin, a cellulose resin, a paraffin wax, or a polyethylene wax, and a natural resin or wax such as wax, tar, glue, urushi, pine resin, or beeswax can be suitably used. These binders are classified into those that volatilize when heated depending on the molecular weight, the type of resin, etc., and those that remain together with the aluminum powder due to thermal decomposition, and are selectively used according to the desired electrical characteristics such as capacitance. be able to.
　また、溶媒も公知のものが使用できる。例えば、水のほか、エタノール、トルエン、ケトン類、エステル類等の有機溶剤を使用することができる。 Also, known solvents can be used. For example, in addition to water, organic solvents such as ethanol, toluene, ketones, and esters can be used.
　皮膜は、ペースト組成物を、例えばローラー、刷毛、スプレー、ディッピング等の塗布方法を用いて形成できるほか、シルクスクリーン印刷等の公知の印刷方法により形成することもできる。 The film can be formed by a known printing method such as silk screen printing in addition to forming the paste composition using, for example, a roller, brush, spray, dipping or the like.
　皮膜はアルミニウム箔基材の片面又は両面に形成する。片面に形成する場合、前記皮膜の合計厚さは、焼結及びエンボス加工を経て最終的に得られる焼結体の総厚みが15～300μmであれば好ましく、80～150μmであればさらに好ましい。両面に形成する場合は、基材を挟んで皮膜を対称に配置することが好ましく、焼結及びエンボス加工を経て最終的に得られる、両面に形成された焼結体の総厚みが15～300μmであれば好ましく、80～150μmであればさらに好ましい。また、両面に形成する場合、片面の皮膜の厚さはアルミニウム箔基材の厚さも含めた全体の厚みの1/3以上であることが好ましい。 The coating is formed on one side or both sides of the aluminum foil substrate. When the film is formed on one side, the total thickness of the coating is preferably 15 to 300 μm, more preferably 80 to 150 μm in total thickness of the sintered body finally obtained through sintering and embossing. When forming on both surfaces, it is preferable to arrange the film symmetrically across the base material, and the total thickness of the sintered body formed on both surfaces finally obtained through sintering and embossing is 15 to 300 μm Is preferable, and 80 to 150 μm is more preferable. Moreover, when forming in both surfaces, it is preferable that the thickness of the film | membrane of one side is 1/3 or more of the whole thickness also including the thickness of an aluminum foil base material.
　なお、前記皮膜の平均厚みは、マイクロメーターで7点測定し、最大値と最小値を除いた5点の平均値からアルミニウム箔の基材厚みを引いた値として求められる。 The average thickness of the film is obtained by measuring 7 points with a micrometer and subtracting the thickness of the aluminum foil base material from the average value of 5 points excluding the maximum and minimum values.
　前記皮膜は、必要に応じて、20～300℃の範囲内の温度で乾燥させても良い。 The film may be dried at a temperature in the range of 20 to 300 ° C. as necessary.
　（第２工程）
　第２工程では、前記皮膜を560～660℃の温度で焼結することにより焼結体を得る。焼結温度は、560～660℃とし、好ましくは570～650℃、より好ましくは580～620℃とする。焼結時間は、焼結温度等により異なるが、通常は5～24時間程度の範囲内で適宜決定することができる。焼結雰囲気は、特に制限されず、例えば真空雰囲気、不活性ガス雰囲気、酸化性ガス雰囲気（大気）、還元性雰囲気等のいずれであっても良いが、特に真空雰囲気又は還元性雰囲気とすることが好ましい。また、圧力条件についても、常圧、減圧又は加圧のいずれでも良い。焼結温度が560℃未満では粉末の焼結が進まず焼結体の強度が弱くなり破断するおそれがある。660℃超過では粉末が溶融する可能性があり、電解コンデンサの電極材として使用した場合に十分な容量が得られないおそれがある。 (Second step)
In the second step, the film is sintered at a temperature of 560 to 660 ° C. to obtain a sintered body. The sintering temperature is 560 to 660 ° C., preferably 570 to 650 ° C., more preferably 580 to 620 ° C. The sintering time varies depending on the sintering temperature and the like, but can usually be appropriately determined within a range of about 5 to 24 hours. The sintering atmosphere is not particularly limited, and may be any one of a vacuum atmosphere, an inert gas atmosphere, an oxidizing gas atmosphere (air), a reducing atmosphere, etc., and particularly a vacuum atmosphere or a reducing atmosphere. Is preferred. Also, the pressure condition may be normal pressure, reduced pressure or increased pressure. If the sintering temperature is lower than 560 ° C., the powder does not sinter and the strength of the sintered body is weakened and may break. If it exceeds 660 ° C, the powder may melt, and there is a possibility that sufficient capacity cannot be obtained when used as an electrode material for electrolytic capacitors.
　なお、第1工程後、第2工程に先立って予め200～450℃の温度範囲で保持時間が5時間以上の加熱処理（脱脂処理）を行なうことが好ましい。かかる脱脂処理により圧延時に付着した油分を充分に除去することができる。加熱処理雰囲気は特に限定されず、例えば真空雰囲気、不活性ガス雰囲気又は酸化性ガス雰囲気中のいずれでも良い。また、圧力条件も、常圧、減圧又は加圧のいずれでも良い。 Note that after the first step, prior to the second step, it is preferable to perform a heat treatment (degreasing treatment) in a temperature range of 200 to 450 ° C. for a holding time of 5 hours or longer. Such degreasing treatment can sufficiently remove oil adhering during rolling. The heat treatment atmosphere is not particularly limited, and may be any of a vacuum atmosphere, an inert gas atmosphere, or an oxidizing gas atmosphere, for example. The pressure condition may be normal pressure, reduced pressure, or increased pressure.
　（第３工程）
　第３工程では、前記焼結体のうち、前記アルミニウム箔基材に対して少なくとも片面の焼結体の表面にRaが0.7～3.5μmである領域を含むようにエンボス加工を施す。通常、焼結直後の皮膜のRaは0.2～0.5μm程度なので、エンボス加工によって皮膜表面を粗くすることができる。エンボス加工の方法は、特に制限されるものでないが、エンボスロール（輪転式型付けロール）を使用した方法が好ましい。エンボスロールのロール表面は、焼結した皮膜のRaが0.7～3.5μmとなるようにその凹凸が所定範囲に調整することができる。焼結した皮膜のRaが0.7μm未満では本発明の効果に乏しく、3.5μmを超えると焼結体に亀裂が入るおそれがある。 (Third step)
In the third step, embossing is performed so that at least one surface of the sintered body of the sintered body includes a region where Ra is 0.7 to 3.5 μm on the surface of the sintered body. Usually, Ra of the film immediately after sintering is about 0.2 to 0.5 μm, so that the film surface can be roughened by embossing. The embossing method is not particularly limited, but a method using an embossing roll (rotary die-setting roll) is preferable. The unevenness of the embossing roll surface can be adjusted within a predetermined range so that Ra of the sintered film is 0.7 to 3.5 μm. If Ra of the sintered film is less than 0.7 μm, the effect of the present invention is poor, and if it exceeds 3.5 μm, the sintered body may crack.
　また、陽極酸化処理時における破断等を回避できる効果を向上させるために、エンボス加工はアルミニウム箔基材の一面に対し、面積割合で70％以上の領域に施されていることが好ましく、80％以上の領域に施されていることがより好ましい。面積割合の上限は限定的ではないが、100％以下、90％以下等に設定することができる。 Further, in order to improve the effect of avoiding breakage during anodizing treatment, the embossing is preferably performed in an area ratio of 70% or more with respect to one surface of the aluminum foil base material, 80% More preferably, it is applied to the above region. The upper limit of the area ratio is not limited, but can be set to 100% or less, 90% or less, and the like.
　（第４工程）
　上記の第３工程において、エッチング処理を施すことなく、本発明の電極材が得られる。本発明の電極材は、第４工程として陽極酸化処理を施すことにより誘電体を形成し、陽極酸化皮膜を被覆させたものを電極とすることができる。陽極酸化処理条件は特に限定されないが、通常は濃度0.01モル以上5モル以下、温度30℃以上100℃以下のホウ酸溶液中で、10 mA/cm2以上400 mA/cm2以下の電流を5分以上印加すれば良い。 (4th process)
In the third step, the electrode material of the present invention can be obtained without performing an etching treatment. The electrode material of the present invention can be formed by applying a anodic oxidation treatment as a fourth step to form a dielectric and coating an anodized film. The anodizing conditions are not particularly limited, but a current of 10 mA / cm 2 or more and 400 mA / cm 2 or less is usually 5 in a boric acid solution having a concentration of 0.01 mol to 5 mol and a temperature of 30 ° C. to 100 ° C. It may be applied for more than a minute.
　以下、実施例及び比較例を示して本発明を具体的に説明する。但し、本発明は、以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples.
　実施例
　平均粒径D50が1.5～9.5μmのアルミニウム粉末（JIS A1080、東洋アルミニウム（株）製、品番AHUZ58FN）100重量部をエチルセルロース系バインダ60重量部（内7重量％が樹脂分、93重量％が溶剤（酢酸ブチル））と混合し、塗工液を得た。 Example 100 parts by weight of an aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ58FN) having an average particle diameter D 50 of 1.5 to 9.5 μm is added to 60 parts by weight of an ethyl cellulose binder (7% by weight is resin content, 93% by weight) % Was mixed with a solvent (butyl acetate) to obtain a coating solution.
　上記塗工液を、厚みが15～50μmのアルミニウム箔（幅500 mm×長さ1000 m）の両面にコンマコーターを用いて塗工し、乾燥した。 The above coating solution was applied to both sides of an aluminum foil (width 500 mm x length 1000 mm) with a thickness of 15 to 50 μm using a comma coater and dried.
　次に、空気中350℃で脱脂し、アルゴンガス雰囲気中にて温度620℃で10時間焼結することにより焼結体を作製した。その後、輪転式型付け機を用いて焼結体にエンボス加工を施すことにより、本発明の電極材を作製した。エンボス加工時に用いるエンボスロールは、所定の表面粗さが得られるよう3水準用いた。 Next, the sintered body was prepared by degreasing in air at 350 ° C. and sintering in an argon gas atmosphere at a temperature of 620 ° C. for 10 hours. Then, the electrode material of this invention was produced by embossing a sintered compact using a rotary type | mold type | molding machine. Three levels of embossing rolls used for embossing were used so as to obtain a predetermined surface roughness.
　比較例
　エンボス加工を施さなかったことを除いて、実施例と同様に作成した。 Comparative Example A comparative example was prepared in the same manner as in Example except that embossing was not performed.
　各電極材の積層厚み、すなわち、エンボス加工後の焼結体の総厚みと、算術平均表面粗さ（Ra）を表１～３に示す。比較例については、Raではなく、焼結体の厚みを示す。 The laminated thickness of each electrode material, that is, the total thickness of the sintered body after embossing and the arithmetic average surface roughness (Ra) are shown in Tables 1 to 3. About a comparative example, it is not Ra but the thickness of a sintered compact is shown.
　実施例については、平均粒径D50が1.5μmのアルミニウム粉末を用いたものを表１に1-1～18として表１に示し、平均粒径D50が3.0μmのアルミニウム粉末を用いたものを2-1～18として表２に示し、平均粒径D50が9.5μmのアルミニウム粉末を用いたものを3-1～18として表３に示す。 For Examples, those using an aluminum powder having an average particle diameter D 50 of 1.5 μm are shown in Table 1 as 1-1 to 18 in Table 1, and using an aluminum powder having an average particle diameter D 50 of 3.0 μm. Are shown in Table 2 as 2-1 to 18, and those using aluminum powder having an average particle diameter D 50 of 9.5 μm are shown in Table 3 as 3-1 to 18.
　また、比較例についてはBL1～18として示す。 Also, comparative examples are shown as BL1-18.
　試験例１
　各電極材を陽極酸化処理ラインにて所定の電圧で陽極酸化処理した。同処理の陽極酸化電圧は、200V、400Ｖ及び600Vの3水準とし、ホウ酸水溶液（50 g/L）中で実施した。当該3水準とも破断無く通過したものを合格とし、1水準でも破断したものは不合格とした。得られた結果を表１～３に示す。各表中、合格及び不合格をそれぞれ○及び×で示す。 Test example 1
Each electrode material was anodized at a predetermined voltage in an anodizing line. The anodic oxidation voltage of the treatment was set at three levels of 200V, 400V and 600V, and was carried out in an aqueous boric acid solution (50 g / L). Those that passed without breaking at all three levels were accepted, and those that broke even at one level were rejected. The obtained results are shown in Tables 1 to 3. In each table, pass and fail are indicated by ○ and ×, respectively.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　上記結果より、この実験の範囲内では、焼結前の粉末平均粒径（D50）、エンボス加工後の焼結体の総厚み、基材厚みの差にかかわりなく、算術平均表面粗さ（Ra）を0.7μm以上に調整することで陽極酸化処理ラインを破断なく通過できるようになった。
　またRaが3.5より大きなものについては、電極材にワレが発生するため検証することができなかった。 From the above results, within the range of this experiment, the arithmetic average surface roughness (D 50 ), regardless of the difference in powder average particle size (D 50 ) before sintering, the total thickness of the sintered body after embossing, and the substrate thickness ( By adjusting Ra) to 0.7 μm or more, it became possible to pass through the anodizing line without breaking.
Further, when Ra was larger than 3.5, the electrode material was cracked and could not be verified.
　試験例２
　平均粒径D50が3μmの粉末を用いた電極材であって、50μmのアルミニウム箔の両面に、焼結層（エンボス加工後の総厚み120μm）を積層し、エンボス加工により片面のRaを1.5μmとした積層箔の容量と、50μmのアルミニウム箔の両面をエッチング処理した、焼結層が積層されていないエッチド箔の容量とを比較評価した。結果を表４に示す。 Test example 2
It is an electrode material using powder with an average particle diameter D 50 of 3 μm. A sintered layer (total thickness 120 μm after embossing) is laminated on both sides of 50 μm aluminum foil, and Ra on one side is 1.5 by embossing. The capacity of the laminated foil having a thickness of μm was compared with the capacity of an etched foil in which both sides of the 50 μm aluminum foil were etched and the sintered layer was not laminated. The results are shown in Table 4.
　積層箔においては、エッチド箔と比べて、いずれの陽極酸化電圧領域でも優位な静電容量値（μF/cm2）を示している。 The laminated foil shows a superior capacitance value (μF / cm 2 ) in any anodic oxidation voltage region as compared with the etched foil.
Figure JPOXMLDOC01-appb-T000004
 　カッコ内は双方を同じ厚みとして換算した場合の静電容量を示す。
Figure JPOXMLDOC01-appb-T000004
 The values in parentheses indicate the capacitance when both are converted to the same thickness.

Claims (7)

  1. 　アルミニウム電解コンデンサ用電極材であって、アルミニウム箔基材の片面又は両面にアルミニウム及びアルミニウム合金の少なくとも1種の粉末の焼結体を有し、前記焼結体のうち、少なくとも片面の焼結体の表面に算術平均粗さ（Ra）が0.7～3.5μmである領域を含むことを特徴とするアルミニウム電解コンデンサ用電極材。 An electrode material for an aluminum electrolytic capacitor having a sintered body of at least one powder of aluminum and an aluminum alloy on one side or both sides of an aluminum foil base material, and at least one side of the sintered body being a sintered body An electrode material for an aluminum electrolytic capacitor comprising a surface having an arithmetic average roughness (Ra) of 0.7 to 3.5 μm.
  2. 　前記焼結体の総厚みが15～300μmである、請求項１に記載のアルミニウム電解コンデンサ用電極材。 The electrode material for an aluminum electrolytic capacitor according to claim 1, wherein the total thickness of the sintered body is 15 to 300 µm.
  3. 　前記粉末の平均粒径が1.5～9.5μmである、請求項１又は２に記載のアルミニウム電解コンデンサ用電極材。 3. The electrode material for an aluminum electrolytic capacitor according to claim 1, wherein the powder has an average particle size of 1.5 to 9.5 μm.
  4. 　前記アルミニウム箔基材の厚さが5～100μmである、請求項１～３のいずれかに記載のアルミニウム電解コンデンサ用電極材。 4. The electrode material for an aluminum electrolytic capacitor according to claim 1, wherein the thickness of the aluminum foil base material is 5 to 100 μm.
  5. 　前記焼結体の表面に、さらに陽極酸化皮膜を有する、請求項１～４のいずれかに記載のアルミニウム電解コンデンサ用電極材。 The electrode material for an aluminum electrolytic capacitor according to any one of claims 1 to 4, further comprising an anodized film on the surface of the sintered body.
  6. 　アルミニウム電解コンデンサ用電極材を製造する方法であって、
    アルミニウム及びアルミニウム合金の少なくとも1種の粉末を含む組成物からなる皮膜をアルミニウム箔基材の片面又は両面に積層する第1工程と、
    前記皮膜を焼結することにより焼結体を得る第2工程と、
    前記焼結体のうち、少なくとも片面の焼結体の表面に算術平均粗さ（Ra）が0.7～3.5μmである領域を含むようにエンボス加工を施す第3工程とを含む製造方法。     A method for producing an electrode material for an aluminum electrolytic capacitor, comprising:
    A first step of laminating a film made of a composition comprising at least one powder of aluminum and an aluminum alloy on one or both surfaces of an aluminum foil base;
    A second step of obtaining a sintered body by sintering the film;
    And a third step of embossing at least one surface of the sintered body so as to include a region having an arithmetic average roughness (Ra) of 0.7 to 3.5 μm.
  7. 　エッチング工程を含まない、請求項６に記載の製造方法。 The manufacturing method according to claim 6, which does not include an etching step.
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