JP2012054448A - Electrode material for aluminum electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode material for an aluminum electrolytic capacitor, which does not need an etching treatment and has improved bending strength, and to provide a method of manufacturing the same.SOLUTION: An electrode material for an aluminum electrolytic capacitor includes: as constituents, a sintered compact of at least one kind of aluminum powder and aluminum alloy powder; and a substrate supporting the sintered compact. In the electrode material for the aluminum electrolytic capacitor, (1) the powder has an average particle diameter Dof 1 μm or more and 50 μm or less, (2) the sintered compact is formed on one side or both sides of the substrate, each sintered compact comprises two or more sintered layers, and the powder contained in an adjacent sintered layer has an average particle diameter Ddifferent by 1.0 μm or more, and (3) the powder contained in the outermost layer among the sintered layers composed of each sintered compact has an average particle diameter Dof more than 10 μm.

Description

  The present invention relates to an electrode material used for an aluminum electrolytic capacitor, and more particularly to an electrode material for an anode used for a medium-high voltage aluminum electrolytic capacitor and a method for producing the same.

  Generally, an aluminum foil is used as an electrode material for an aluminum electrolytic capacitor. When the aluminum foil is subjected to an etching treatment, etching pits are formed, and the surface area can be increased. Moreover, an oxide film is formed by anodizing the surface, 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.

  However, in the etching process, an aqueous hydrochloric acid solution containing sulfuric acid, phosphoric acid, nitric acid or the like in hydrochloric acid must be used. That is, hydrochloric acid has a large environmental load, and its treatment is also a burden on the process and economy.

  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 treatment. For example, Patent Document 1 proposes a method of enlarging the surface area by depositing and sintering aluminum fine powder on the surface of an aluminum foil by vapor deposition. Also, in Patent Document 2, a method is proposed in which the surface area is increased by laminating and sintering aluminum particles while maintaining voids.

  However, the inventors of the present application tried to manufacture a sintered body by the methods disclosed in these documents, and as the laminated thickness was increased to improve the capacity, the bending strength of the sintered body was lowered. I understood. Therefore, there is a problem that the sintered body is damaged when such a sintered body is wound to form a capacitor element.

JP-A-2-267916 JP 2008-98279 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electrode material for an aluminum electrolytic capacitor that does not require an etching process and has improved bending strength, and a method for manufacturing the same.

  As a result of earnest research to achieve the above object, the present inventor can achieve the above object when a sintered body of at least one powder of aluminum and aluminum alloy is formed from a specific sintered layer. As a result, the present invention has been completed.

The present invention relates to the following electrode material for an aluminum electrolytic capacitor and a method for producing the same.
1. An electrode material for an aluminum electrolytic capacitor comprising a sintered body of at least one powder of aluminum and an aluminum alloy,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is composed of three or more sintered layers, and the powder contained in the adjacent sintered layers has an average particle size D ₅₀ different by 1.0 μm or more,
(3) of the sintered layer forming the sintered body, the said powder contained in the sintered layer of the outermost layer, the average particle diameter D ₅₀ is more than 10 [mu] m,
The electrode material for aluminum electrolytic capacitors characterized by the above-mentioned.
2. An electrode material for an aluminum electrolytic capacitor comprising a sintered body of at least one powder of aluminum and an aluminum alloy and a base material supporting the sintered body as constituent elements,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is formed on one side or both sides of the base material, each sintered body is composed of two or more sintered layers, and the powder contained in the adjacent sintered layers is an average. The particle size D ₅₀ differs by 1.0 μm or more,
(3) of the sintered layers constituting each sintered body, the said powder contained in the sintered layer of the outermost layer, the average particle diameter D ₅₀ is more than 10 [mu] m,
The electrode material for aluminum electrolytic capacitors characterized by the above-mentioned.
3. Item 3. The electrode material for an aluminum electrolytic capacitor according to Item 2, wherein the substrate is an aluminum foil.
4). The sintered body is formed on both surfaces of the base material,
(1) The thickness of the sintered body on each surface is 35 μm or more and 250 μm or less,
(2) Each sintered layer included in the sintered body on each surface has a thickness of 15 μm or more.
Item 4. The electrode material for an aluminum electrolytic capacitor as described in 2 or 3 above.
5). A method for producing an electrode material for an aluminum electrolytic capacitor, comprising:
A step of laminating two or more layers of a film comprising a composition containing at least one powder of aluminum and an aluminum alloy on one side of a substrate, wherein (i) the powder contained in each film has an average particle size D ₅₀ Is not less than 1 μm and not more than 50 μm, and (ii) the powder contained in the adjacent film has an average particle diameter D ₅₀ different by 1.0 μm or more, and (iii) the powder contained in the outermost layer film has an average particle diameter A first step with D ₅₀ exceeding 10 μm;
A second step of sintering the two or more layers at a temperature of 560 ° C. or more and 660 ° C. or less after the first step;
And does not include an etching step,
The manufacturing method characterized by the above-mentioned.
6). Item 6. The manufacturing method according to Item 5, wherein the two or more layers are formed on both surfaces of the substrate.
7). Item 7. The manufacturing method according to Item 5 or 6, further comprising a third step of anodizing the sintered two or more layers.

ADVANTAGE OF THE INVENTION According to this invention, the electrode material for aluminum electrolytic capacitors which contains the sintered compact of the powder of at least 1 sort (s) of aluminum and aluminum alloy as a component is provided. This sintered body, the average particle diameter D ₅₀ of the powder is at 1μm or more 50μm or less and comprising a plurality of sintered layers. The average particle diameter D ₅₀ of the powder having an average particle diameter D ₅₀ of the powder contained in the adjacent sintered layer is included in the sintered layer of 1.0μm or more different and outermost exceeds 10 [mu] m. Thereby, the bending strength of the electrode material after sintering can be improved.

  Moreover, even when the thickness of the sintered body is large, a high electrostatic capacity can be ensured. Furthermore, the particles have a unique structure in which the particles are sintered while maintaining voids, and a high capacitance can be ensured. For this reason, it can be used not only for low pressure but also for medium and high voltage capacitors.

It is a figure which shows the cross section of the electrode material produced in Examples 1-5. It is a figure which shows the cross section of the electrode material produced in Comparative Examples 1-3. 2 is an image observed by a scanning electron microscope of a cross section of the electrode material produced in Example 1. FIG. It is an observation image by the scanning electron microscope of the cross section of the electrode material produced in Comparative Examples 1 and 2. FIG.

1. Electrode Material for Aluminum Electrolytic Capacitor The electrode material for aluminum electrolytic capacitor of the present invention can be broadly divided into two types, that is, the electrode material of the first aspect having no base material and the second aspect having the base material as described below. it can.

The electrode material of the first aspect is an electrode material for an aluminum electrolytic capacitor comprising a sintered body of at least one powder of aluminum and an aluminum alloy,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is composed of three or more sintered layers, and the powder contained in the adjacent sintered layers has an average particle size D ₅₀ different by 1.0 μm or more,
(3) of the sintered layer forming the sintered body, the said powder contained in the sintered layer of the outermost layer, the average particle diameter D ₅₀ is equal to or more than 10 [mu] m.

The electrode material of the second aspect is an electrode material for an aluminum electrolytic capacitor including a sintered body of at least one powder of aluminum and an aluminum alloy and a base material supporting the sintered body as constituent elements,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is formed on one side or both sides of the base material, each sintered body is composed of two or more sintered layers, and the powder contained in the adjacent sintered layers is an average. The particle size D ₅₀ differs by 1.0 μm or more,
(3) of the sintered layers constituting each sintered body, the powder contained in the sintered layer of the outermost layer has an average particle diameter D ₅₀ is equal to or more than 10 [mu] m.

Electrode material of the present invention having the above characteristics, excluding both the first and second aspects, different average particle size D ₅₀ of the powder contained in the adjacent sinter layers than 1.0 .mu.m, the outermost layer (substrate by average particle size D ₅₀ of the powder contained in the sintered layer of the layer) that is exposed to the atmosphere is more than 10 [mu] m, it is possible to improve the strength bending while securing high capacitance.

  Hereinafter, the electrode material of the first aspect and the second aspect will be described.

  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), and an alloy containing one or more elements such as zirconium (Zr). The content of these elements in the aluminum alloy is preferably 100 ppm by weight or less, particularly 50 ppm by weight or less.

As the powder, one having an average particle diameter D ₅₀ before sintering of 1 μm or more and 50 μm or less is used. Especially when the average particle diameter D ₅₀ of 3μm or more 15μm or less of the powder can be suitably used as an electrode material for aluminum electrolytic capacitors of middle and high capacity. The average particle size D ₅₀ in the present specification, the particles corresponding to 50% th of the total number of particles in the particle size distribution curve obtained by seeking the number of particles corresponding to the particle size and particle size by laser diffraction method The particle size. The average particle diameter D ₅₀ of the powder after sintering, the cross-section of the sintered body is measured by observing by a scanning electron microscope. For example, the powder after sintering is partially melted or in a state where the powders are connected to each other, but the portion having a substantially circular shape can be regarded as a particle approximately. That is, in the particle size distribution curve obtained by obtaining these particle sizes and the number of particles corresponding to the particle size, the particle size of the particles corresponding to the 50% of the total number of particles is the average particle size D of the powder after sintering. ₅₀ . The average particle diameter D ₅₀ after sintering and an average particle diameter D ₅₀ before sintering obtained in the above is substantially the same.

  The shape of the powder is not particularly limited, and any of a spherical shape, an indeterminate shape, a scale shape, a fiber shape, and the like can be suitably used. In particular, powder made of spherical particles is preferable.

  What is manufactured by a well-known method can be used for the said powder. 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.

The electrode material of the first aspect, the sintered body of the powder consists of three layers or more sintered layer, the powder contained in the adjacent sintered layer has an average particle diameter D ₅₀ more than 1.0 .mu.m (preferably 1.0 μm or more and 12.0 μm or less), the powder contained in the sintered layer of the outermost layer (two layers at both ends) of the sintered body has an average particle diameter D ₅₀ exceeding 10 μm. Thus exceed an average particle diameter D ₅₀ of 10μm of the powder contained in the sintered layer of the outermost layer, different the average particle diameter D ₅₀ of the powder contained inside the sintered layer adjacent thereto 1.0μm more Thereby, the bending strength of the sintered body can be improved.

The aluminum electrolytic capacitor preferably has a bending strength of at least 10 times. If the bending strength is less than 10 times, the sintered body may be damaged during the production of the aluminum electrolytic capacitor. More preferably, the number of bendings is preferably 20 times or more. As further has an average particle diameter D ₅₀ of the powder contained in the inner layer side is smaller, it is possible to secure a high electrostatic capacitance.

The structure of the sintered body of the electrode material of the first aspect, for example, the average particle diameter _{D 50} of 1 to 7 [mu] m (preferably 1 to 5 [mu] m) inner layer and the average particle size _{D 50} sandwiching the of 10 to 50 most A three-layer structure consisting of an outer layer (two layers at both ends, preferably 10 to 25 μm) is mentioned.

  Each sintered layer is preferably one in which the powders are sintered while maintaining gaps therebetween. Specifically, it is preferable that the powders are connected by sintering while maintaining voids, and have, for example, a three-dimensional network structure as shown in each image of FIG. 3 or FIG. 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 each sintered layer can be appropriately set according to the desired capacitance or the like, usually within a range of 30% or more. The porosity can also be controlled by, for example, the particle diameter of the starting aluminum or aluminum alloy powder, the composition of the paste composition containing the powder (resin binder), and the like.

  In a 2nd aspect, the base material which supports the said sintered compact is included. The material of the substrate is not particularly limited, but a metal foil that does not deteriorate or volatilize during sintering is preferable.

  As the metal foil, aluminum foil is particularly preferably used. In this case, an aluminum foil having substantially the same composition as the sintered body may be used, or a foil having a different composition may be used. Prior to forming the sintered body, the surface of the aluminum foil may be roughened in advance. 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 an 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 ( Limiting the content of aluminum alloy or the above unavoidable impurity elements to which at least one alloy element of Ti), vanadium (V), gallium (Ga), nickel (Ni) and boron (B) is added within the required range Also included aluminum.

  The thickness of the aluminum foil is not particularly limited, but is preferably in the range of 5 μm to 50 μm, particularly 10 μm to 50 μm.

  What was manufactured by a well-known method can be used for said aluminum foil. 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.

  In the middle of the cold rolling step, an intermediate annealing treatment may be performed in the range of 50 ° C. to 500 ° C., particularly 150 ° C. 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 ° C. to 650 ° C., particularly 350 ° C. to 550 ° C.

  In the second aspect, the sintered body is formed on one side or both sides of the substrate. When forming on both surfaces, it is preferable to arrange symmetrically the sintered body (and the sintered layer contained therein) sandwiching the base material as shown in FIG. The average thickness of each sintered body is preferably 35 to 250 μm, and the average thickness of each sintered layer contained in the sintered body is preferably 15 μm or more. These values apply to both cases where the substrate is formed on one side or both sides of the substrate, but when formed on both sides, the thickness of the sintered body on one side is 1 of the total thickness (including the substrate thickness). / 3 or more is preferable.

  The average thickness of the sintered body is an average value of 5 points excluding the maximum value and the minimum value measured at 7 points with a micrometer. In addition, the average thickness of each sintered layer was determined by visually drawing a straight line at the interface of each sintered layer in a scanning electron micrograph (three sheets) of about 200 times that the sintered body was all within the photographing range. It is the value which calculated | required the ratio of thickness, calculated the thickness of each sintered layer from the average thickness of the whole sintered compact calculated | required with the micrometer, and calculated | required the average value for 3 sheets.

Specifically, the structure of the sintered body of the electrode material of the second aspect, for example, as shown in Example 1, the average particle diameter D ₅₀ of the powder 1 to 7 [mu] m (preferably 1 to 5 [mu] m) Examples include a sintered layer (inner layer) and a powder sintered layer (outer layer and two layers) having an average particle diameter D50 of 10 to ₅₀ μm (preferably 10 to 25 μm).

Further, for example, a sintered layer of the powder of an average particle size _{D 50} 1 to 7 [mu] m (preferably 1 to 5 [mu] m) (inner layer), the average particle diameter _{D 50} of the powder 6～50Myuemu (preferably 6～25Myuemu) baked A structure in which three layers of a sintered layer (outer layer) of a binder layer (intermediate layer) and a powder having an average particle diameter D ₅₀ of 10 to ₅₀ μm (preferably 10 to 25 μm) is laminated.

  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.

  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 (electrode foil) as it is or without being subjected to 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. The capacitor element is impregnated with an electrolytic solution, and the capacitor element includes the electrolytic solution. Is stored in an exterior case, and the case is sealed with a sealing body to obtain an electrolytic capacitor.

2. Method for producing electrode material for aluminum electrolytic capacitor The method for producing the electrode material for aluminum electrolytic capacitor of the present invention is not limited. For example, if the electrode material of the first aspect,
A first step of laminating aluminum and a coating comprising a composition comprising at least one powder of an aluminum alloy 3 or more layers, wherein the powder has an average particle diameter D ₅₀ more than 1μm contained in (i) each film and at 50μm or less, the powder contained in the coating (ii) adjacent different average particle diameter _{D 50} above 1.0 .mu.m, the powder contained in (iii) the outermost layer of the coating, the average particle diameter _{D 50} A first step exceeding 10 μm;
A second step of sintering the three or more layers at a temperature of 560 ° C. or more and 660 ° C. or less after the first step,
And the manufacturing method which does not include an etching process is employable.

  In addition, although the electrode material of a 1st aspect does not contain a base material, when laminating | stacking the said 3 or more layer film | membrane, resin (resin film) which volatilizes at the time of sintering can be used as a base material. Since the resin film volatilizes and disappears during sintering, the electrode material does not include a base material.

Moreover, if it is the electrode material of a 2nd aspect,
A laminating aluminum and aluminum alloys of at least one of a film made from a composition comprising a powder base two or more layers, wherein the powder contained in (i) each coating, the average particle diameter D ₅₀ 1 [mu] m (Ii) The powder contained in the adjacent coating has an average particle size D ₅₀ different by 1.0 μm or more, and (iii) the powder contained in the outermost coating has an average particle size D _50. A first step exceeding 10 μm;
A second step of sintering the two or more layers at a temperature of 560 ° C. or more and 660 ° C. or less after the first step;
And the manufacturing method which does not include an etching process is employable.

Hereinafter, the manufacturing method of the electrode material of the second aspect will be described as an example.
(First step)
In the first step, two or more layers of a film comprising a composition containing at least one powder of aluminum and an aluminum alloy are formed on the substrate. Here, (i) the powder contained in each coating, the average particle diameter _{D 50} is at 1μm or more 50μm or less, (ii) the powder contained in the adjacent film, the average particle diameter _{D 50} 1.0μm or more (preferably 1.0μm or 12.0μm or less) different, the powder contained in (iii) the outermost layer of the coating, the average particle size _{D 50} is greater than 10 [mu] m.

  As the composition (component) of aluminum and aluminum alloy, those listed above can be used. As the powder, for example, pure aluminum powder having an aluminum purity of 99.8% by weight or more is preferably used.

  The composition may contain a resin 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 resin binder and a solvent as a paste composition. Thereby, a film can be formed efficiently.

  The resin 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 epoxy resin, urea resin, phenol resin, acrylonitrile resin, cellulose resin, paraffin wax, polyethylene wax, or natural resin such as wax, tar, glue, urushi, pine resin, beeswax, or wax can be preferably 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 can be properly used depending on the desired electrostatic properties and the like. .

  Also, known solvents can be used. For example, in addition to water, organic solvents such as ethanol, toluene, ketones, and esters can be used.

  For forming the film, the paste composition can be formed by using a coating method such as roller, brush, spray, dipping or the like, or can be formed by a known printing method such as silk screen printing.

  Two or more layers are formed on one or both sides of the substrate. When forming on both surfaces, it is preferable to arrange two or more layers symmetrically across the substrate.

  The average thickness of the two or more layers is preferably 35 to 250 μm, and the average thickness of each layer included in the two or more layers is preferably 15 μm or more. These figures apply to both cases where the substrate is formed on one side or both sides, but when formed on both sides, the thickness of the film formed on one side of the substrate is the total thickness (substrate thickness). 1) or more).

The film may be dried at a temperature in the range of 20 ° C. or more and 300 ° C. or less as necessary.
(Second step)
In the second step, the film is sintered at a temperature of 560 ° C. or higher and 660 ° C. or lower. The sintering temperature is 560 ° C. or higher and 660 ° C. or lower, preferably 560 ° C. or higher and lower than 660 ° C., more preferably 570 ° C. or higher and 659 ° C. or lower. 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.

In addition, it is preferable to perform the heat processing (degreasing process) for 5 hours or more in a temperature range of 100 degreeC or more and 600 degrees C or less beforehand after a 1st process prior to a 2nd process. 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.
(Third step)
In the second step, the electrode material of the present invention is obtained. This can be used as it is as an electrode for an aluminum electrolytic capacitor (electrode foil) without etching. On the other hand, the electrode material can be formed as an electrode by subjecting it to an anodization treatment as a third step as necessary, thereby forming a dielectric. The anodizing conditions are not particularly limited. Usually, a current of about 10 mA / cm ^{2 to} 400 mA / cm ² is applied 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.

  Hereinafter, the present invention will be specifically described with reference to comparative examples and examples. However, the present invention is not limited to the examples.

According to the following procedure, the electrode material of a comparative example and an Example was produced, and the electrostatic capacitance of the obtained electrode material was measured, respectively. The capacitance was measured in an aqueous solution of ammonium borate (3 g / L) after performing a chemical conversion treatment of 250 V on the electrode material in an aqueous boric acid solution (50 g / L). The measurement projected area was 10 cm ² .

  Further, the obtained electrode material (JIS 1N30-H18, 500 mm × 500 mm) was 90 degrees (R = 3.5 ± 0.35 mm) in the plane direction using a folding tester (MIT-S manufactured by Toyo Seiki Co., Ltd.). The electrode material was repeatedly bent until the electrode material was broken, and the number of times of bending withstanding the fracture was measured.

Comparative Example 1
60 parts by weight of aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ58FN) having an average particle diameter D ₅₀ of 3 μm is mixed with 40 parts by weight of a cellulose binder (7% by weight is a resin component), and a solvent (ethyl cellosorb) To obtain a coating liquid A having a solid content of 60% by weight. As shown in FIG. 2, the coating liquid A was coated on both sides of an aluminum foil (JIS 1N30-H18, 500 mm × 500 mm) having a thickness of 30 μm using a comma coater, and then dried. In the coating method, after coating 50 μm of the coating liquid A on one side, drying in a furnace at 100 ° C. for 2 minutes, coating on the opposite side and drying in the same manner were repeated twice.

  Next, the electrode material was produced by sintering at 650 degreeC for 7 hours in argon gas atmosphere. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 0 times and the capacitance was 51.8 μF / 10 cm ² .

Comparative Example 2
Aluminum powder having an average particle diameter _{D 50} of 4 [mu] m (JIS A1080, Toyo Aluminum Co., Ltd., No. AHUZ580F) except for using, in the same manner as in Comparative Example 1 to obtain a coating solution B. As shown in FIG. 2, an electrode material was prepared in the same manner as in Comparative Example 1 except that the coating liquid B was applied to both surfaces of the aluminum foil. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 0 times and the capacitance was 48.3 μF / 10 cm ² .

Comparative Example 3
Aluminum powder having an average particle diameter _{D 50} of 5 [mu] m (JIS A1080, Toyo Aluminum Co., Ltd., No. AHUZ58CN) except for using, in the same manner as in Comparative Example 1 to obtain a coating liquid C. As shown in FIG. 2, an electrode material was prepared in the same manner as in Comparative Example 1 except that the coating liquid C was applied to both surfaces of the aluminum foil. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was folded seven times and the capacitance was 37.2 μF / 10 cm ² .

Example 1
As shown in FIG. 1, the coating liquid A prepared in Comparative Example 1 was applied to a thickness of 50 μm using a comma coater on both sides of an aluminum foil (JIS 1N30-H18, 500 mm × 500 mm) having a thickness of 30 μm. Dried.

Furthermore, 60 parts by weight of an aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ530C) having an average particle diameter D ₅₀ of 15 μm is mixed with 40 parts by weight of a cellulose-based binder (7% by weight is a resin component) to obtain a solid content. A 60 wt% coating solution D was obtained.

  The coating liquid D was applied to both sides of the aluminum foil on which the film was formed using a comma coater to a thickness of 50 μm and dried.

  Next, the electrode material was produced by sintering at 635 degreeC for 7 hours in argon gas atmosphere. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 35 times and the capacitance was 35.7 μF / 10 cm ² .

Example 2
As shown in FIG. 1, an electrode material was prepared in the same manner as in Example 1 except that the coating liquid B prepared in Comparative Example 2 was used for the inner film. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 40 times and the capacitance was 33.6 μF / 10 cm ² .

Example 3
As shown in FIG. 1, an electrode material was produced in the same manner as in Example 1 except that the coating liquid C prepared in Comparative Example 3 was used for the inner film. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material had a folding number of 67 times and an electrostatic capacity of 27.9 μF / 10 cm ² .

Example 4
60 parts by weight of aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ560F) having an average particle diameter D ₅₀ of 9 μm is mixed with 40 parts by weight of a cellulose-based binder (7% by weight is the resin content), and the solid content is 60% by weight. % Coating liquid E was obtained. As shown in FIG. 1, an electrode material was prepared in the same manner as in Example 1 except that the coating liquid E was used for the inner film. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 164 times and the capacitance was 23.3 μF / 10 cm ² .

Example 5
60 parts by weight of aluminum powder (JIS A1080, manufactured by Toyo Aluminum Co., Ltd., product number AHUZ520F) having an average particle diameter D ₅₀ of 48 μm is mixed with 40 parts by weight of a cellulose-based binder (7% by weight is the resin content), and the solid content is 60 weights. % Coating liquid F was obtained.
As shown in FIG. 1, an electrode material was prepared in the same manner as in Example 1 except that the coating liquid A was used for the inner film and the coating liquid F was used for the outer film. The thickness of the electrode material after sintering was about 230 μm.

As shown in Table 1, the obtained electrode material was bent 75 times and the capacitance was 28.0 μF / 10 cm ² .

Table 1 As is apparent from the results, than when the average particle diameter D ₅₀ was formed a sintered body made of a sintered layer of one layer using aluminum powder 3 to 5 [mu] m (Comparative Example 1-3), When the sintered body is formed of two or more sintered layers having the average particle diameter D _{50 of the} outermost layer of 10 μm or more and the average particle diameter D ₅₀ of 1.0 μm or more (Examples 1 to 5) However, it can be seen that a high electrostatic capacity is secured and the bending strength is improved.

Claims (7)

An electrode material for an aluminum electrolytic capacitor comprising a sintered body of at least one powder of aluminum and an aluminum alloy,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is composed of three or more sintered layers, and the powder contained in the adjacent sintered layers has an average particle size D ₅₀ different by 1.0 μm or more,
(3) of the sintered layer forming the sintered body, the said powder contained in the sintered layer of the outermost layer, the average particle diameter D ₅₀ is more than 10 [mu] m,
The electrode material for aluminum electrolytic capacitors characterized by the above-mentioned. An electrode material for an aluminum electrolytic capacitor comprising a sintered body of at least one powder of aluminum and an aluminum alloy and a base material supporting the sintered body as constituent elements,
(1) the powder has an average particle diameter _{D 50} is at 1μm or more 50μm or less,
(2) The sintered body is formed on one side or both sides of the base material, each sintered body is composed of two or more sintered layers, and the powder contained in the adjacent sintered layers is an average. The particle size D ₅₀ differs by 1.0 μm or more,
(3) of the sintered layers constituting each sintered body, the said powder contained in the sintered layer of the outermost layer, the average particle diameter D ₅₀ is more than 10 [mu] m,
The electrode material for aluminum electrolytic capacitors characterized by the above-mentioned.   The electrode material for an aluminum electrolytic capacitor according to claim 2, wherein the base material is an aluminum foil. The sintered body is formed on both surfaces of the base material,
(1) The thickness of the sintered body on each surface is 35 μm or more and 250 μm or less,
(2) Each sintered layer included in the sintered body on each surface has a thickness of 15 μm or more.
The electrode material for aluminum electrolytic capacitors according to claim 2 or 3. A method for producing an electrode material for an aluminum electrolytic capacitor, comprising:
A step of laminating two or more layers of a film comprising a composition containing at least one powder of aluminum and an aluminum alloy on one side of a substrate, wherein (i) the powder contained in each film has an average particle size D ₅₀ Is not less than 1 μm and not more than 50 μm, and (ii) the powder contained in the adjacent film has an average particle diameter D ₅₀ different by 1.0 μm or more, and (iii) the powder contained in the outermost layer film has an average particle diameter A first step with D ₅₀ exceeding 10 μm;
A second step of sintering the two or more layers at a temperature of 560 ° C. or more and 660 ° C. or less after the first step;
And does not include an etching step,
The manufacturing method characterized by the above-mentioned.   The manufacturing method according to claim 5, wherein the two or more layers are formed on both surfaces of the substrate.   The manufacturing method according to claim 5 or 6, further comprising a third step of anodizing the sintered two or more layers.

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