JP2007165775A - Drying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying apparatus that can stably fabricate thin capacitor elements with few short circuit failures and few variations in element shapes, attain high capacitance by increasing the number of lamination layers of capacitor elements in a solid electrolytic capacitor chip, and manufacture multilayer solid electrolytic capacitors with few variations in equivalent series resistance. <P>SOLUTION: The drying apparatus has an air-blowing mechanism in which a plurality of ventilation flues are included that have a sectionalized cross section shape, wherein preferably, an air supply side for the ventilation flues has an ample capacity, the plurality of ventilation flues are equally long, and the length of the ventilation flue is five or more times as large as the diameter of an inscribed circle of its cross section shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drying device and its use. In particular, the present invention relates to a drying apparatus suitable for a manufacturing process of a device element for an electronic device such as a capacitor element, a solid electrolytic capacitor manufactured using the apparatus, and an element for an electronic device.

Recently, electronic devices have been made smaller and higher in frequency, and electronic components used therefor are also required to be reduced in size. In general, however, the demand for miniaturization is met by a laminated chip shape.
For example, the example shown in FIG. 1 as an example of a capacitor element is a cross-sectional view of a conventional chip-shaped multilayer solid electrolytic capacitor in which a plurality of capacitor elements are stacked. Capacitor elements (11) inside the exterior resin (16) are arranged in the same direction, and the cathode portions (11a) of the capacitor elements (11) are joined with a conductive adhesive, respectively, and cathode lead portions (13) and a conductive adhesive. Further, the anode part (11b) of the capacitor element (11) shows a state where the anode part (11b) is joined by resistance welding at the joint part (15) with the anode lead part (14). 16).

  In general, an electrolytic oxidation polymerization method and a chemical oxidation polymerization method are known as methods for forming a solid electrolyte layer on a dielectric oxide film. The chemical oxidative polymerization method is difficult to control the reaction or the form of the polymer film, but various methods have been proposed because it is easy to form a solid electrolyte and enables mass production in a short time. For example, a method of forming a solid electrolyte having a layered structure by alternately repeating a step of immersing an anode substrate in a monomer-containing solution and a step of immersing in an oxidant-containing solution (Patent Document 1: Patent) No. 3187380). According to this method, a solid electrolytic capacitor having a high capacity, low impedance, and excellent heat resistance can be produced by forming a solid electrolyte layer having a layered structure with a film thickness of 0.01 to 5 μm. There is a problem that the space between the layers of the layered structure portion forming the solid electrolyte layer is large, and as a multilayer capacitor element in which a plurality of capacitor elements are stacked, a further reduction in thickness of the entire solid electrolyte layer is required.

  As a method for forming a solid electrolyte in the pores and the outer surface of the capacitor element without forming a solid electrolyte layer having a layered structure, the anode substrate is immersed in a solution containing a monomer compound and then polymerized in an oxidizer solution. A method of repeating a drying cycle after washing an oxidizing agent is disclosed (Patent Document 2: Japanese Patent Laid-Open No. 9-306788), but the solid electrolyte layer formed by this method has a space between the layers. Therefore, the resistance to external stress was insufficient.

  On the other hand, a method for promoting the formation of a conductive polymer film by using a solution containing a monomer or a solution containing an oxidizing agent as a suspension containing fine particles has been proposed, and a method of adding conductive polymer particles as fine particles (Patent Document 3). : Japanese Patent No. 3478987), a method of adding colloidal particles containing polymer fine particles (Patent Document 2), and a method of adding inorganic fine particles (Patent Document 4: Japanese Patent Laid-Open No. 11-283875).

Japanese Patent No. 3187380 Japanese Patent Laid-Open No. 9-306788 Japanese Patent No. 3478987 JP-A-11-283875

  For example, a solid electrolytic capacitor having a predetermined capacity is usually formed by laminating a plurality of capacitor elements, connecting an anode lead wire to an anode terminal, connecting a cathode lead wire to a conductor layer on the solid electrolytic layer, and further epoxy the whole. It is manufactured by sealing with an insulating resin such as a resin. Since a plurality of stacked capacitor element groups cannot exceed the thickness of the solid electrolytic capacitor, the capacitor elements are required to be thin and have excellent electrical characteristics.

  The thickness of the capacitor element is the sum of the thickness of the valve action metal, the thickness of the dielectric film formed on the valve action metal surface, the thickness of the solid electrolyte layer, and the thickness of the conductor layer. It is necessary to reduce these thicknesses in order to obtain Here, the valve action metal can be easily obtained by using a commercially available aluminum foil or the like, and the dielectric film is less than 1 μm when aluminum is used as the valve action metal. Since the oxide film corresponds to this, it hardly affects the thickness of the entire capacitor element. It is common to use conductive paste such as silver paste or carbon paste for the conductor layer, but as a method of applying the paste to the capacitor element, a uniform and thin film such as printing, dipping, dispensing etc. is repeated with high accuracy. Methods of coating are known, and by using these methods, a thin conductive layer having a uniform thickness can be provided on the capacitor element.

  However, in the case of the chemical oxidation polymerization method, the thickness of the solid electrolyte layer is not uniform even if the polymerization conditions are carefully controlled. This is because if the solid electrolyte layer has a portion that is too thin, the paste or the like tends to come into direct contact with the dielectric film, leading to an increase in leakage current. In addition, since the number of capacitor elements that can be stacked on a solid electrolytic capacitor of a predetermined size is limited by the thickness of the element, the capacity of the solid electrolytic capacitor cannot be increased. Furthermore, if the thickness of the solid electrolyte layer is not uniform, the contact area between the stacked capacitor elements and the capacitor elements is reduced, and there is a problem that the equivalent series resistance (ESR) is increased.

  An object of the present invention is to solve the above-mentioned problems, stably produce a thin capacitor element with little variation in element shape without increasing short-circuit defects, and reduce the number of capacitor elements stacked in a solid electrolytic capacitor chip. An object of the present invention is to provide a means capable of increasing the capacity by increasing the number of capacitors and manufacturing a multilayer solid electrolytic capacitor element having a small variation in equivalent series resistance.

  As a result of intensive studies in view of the above problems, the present inventors have heretofore been known as a method of forming a solid electrolyte layer by polymerizing a monomer with an oxidizing agent on a dielectric film formed on a valve action metal surface. In the process of immersing and drying in a solution containing a monomer and the process of immersing and drying in a suspension containing an oxidant, the air velocity during drying greatly affects the shape and electrical characteristics of the solid electrolyte layer. In consideration of this, a drying device having a plurality of air passages divided in order to make the wind speed uniform is developed, and a step of immersing and drying in a monomer-containing solution using this drying device and a suspension containing an oxidizing agent are developed. The present inventors have found that a solid electrolyte excellent in shape stability and electrical characteristics can be formed with a uniform film thickness by performing a step of dipping in a turbid liquid and drying.

  The drying speed is generally determined by three elements of temperature, humidity, and wind speed, but the temperature and humidity can be easily controlled by using a commercially available air conditioner. On the other hand, the wind speed decreases on the wall surface of the ventilation path due to wall resistance, and the capacitor element itself becomes resistant to the air flow. Therefore, the wind speed in the drying apparatus is complicated and completely different depending on the location. Since the drying apparatus of the present invention can appropriately control the flow rate or speed of drying air, it can form a solid electrolyte having a uniform film thickness, excellent shape stability, and excellent electrical characteristics.

ADVANTAGE OF THE INVENTION According to this invention, the drying apparatus for solid electrolytic capacitor manufacture which consists of a structure shown below, the solid electrolytic capacitor manufactured using the apparatus, and the element for electronic devices are provided.
1. A drying apparatus comprising a blower mechanism in which a plurality of ventilation paths having a sectioned section shape are included.
2. 2. The drying apparatus according to 1 above, wherein the cross-sectional shapes are the same or similar.
3. Said 1 or 2 which has a ventilation mechanism provided with the chamber which has the capacity | capacitance more than the amount of dry air per second on the air supply side and / or air collection | recovery side of the several ventilation path which has the divided cross-sectional shape. The drying apparatus described in 1.
4). 4. The drying apparatus according to any one of the above items 1 to 3, further including a blower mechanism connected to the chamber and having a plurality of ventilation paths having a sectioned section having the same length.
5. The drying apparatus according to any one of the above items 1 to 4, further comprising a blower mechanism having a plurality of ventilation paths whose length of the ventilation path is five times or more the inscribed circle diameter of the sectional shape of the ventilation path.
6). The drying apparatus according to any one of 1 to 5, wherein the cross-sectional shape of the ventilation path is a right triangle, an isosceles triangle, a regular triangle, a parallelogram, a rectangle, a rhombus, a trapezoid, a rectangle, a square, or a regular hexagon.
7). The air whose temperature and / or humidity is controlled flows into the ventilation path through a chamber connected to the ventilation path inlet, flows out from the ventilation path outlet in a laminar flow state, and dries the member installed at the ventilation path outlet. The drying apparatus in any one of 1-6.
8). 8. The drying apparatus according to any one of 1 to 7, which dries a solution attached to a chemical conversion foil to be a capacitor element.
9. Any one of the above 1 to 8 is a device for drying a solution adhering to a plurality of chemical conversion foils lowered to a holding body, wherein the side length of the cross-sectional shape of the ventilation path is 1 to 10 times the mutual interval between the chemical conversion foils. A drying apparatus according to claim 1.
10. The drying apparatus according to any one of 1 to 9 above, wherein the solution attached to the chemical conversion foil is installed on one or both sides of the chemical conversion foil lowered to the holding body.
11. The drying apparatus according to any one of 1 to 10 above, wherein the ventilation speed of the ventilation path is 0.05 to 1.5 m / s.
12 The drying apparatus according to any one of 1 to 11, which has a bypass ventilation path along with an air ventilation path for drying the solution adhering to the chemical conversion foil.
13. 13. The drying device according to 12 above, wherein an air volume adjusting damper is provided in the bypass ventilation path.
14 14. The drying apparatus according to 12 or 13 above, wherein the amount of air in the bypass ventilation path is not more than 10 times the amount of air in the ventilation path of air for drying the solution adhering to the chemical conversion foil.
15. The above-mentioned 12 to 12 having a sensor for measuring the temperature and / or humidity of the blown air in either or both of the air ventilation path and the bypass ventilation path for drying the solution adhering to the chemical conversion foil, and controlling the atmosphere of the blowing air The drying apparatus according to any one of 14.
16. In a method for manufacturing a solid electrolytic capacitor including a capacitor element in which a solid electrolyte layer is formed on a dielectric film formed on a valve action metal surface, the step of drying by immersing the solid electrolyte layer in a solution containing a monomer (drying) Solid formed by drying using the drying apparatus according to any one of 1 to 15 above in the case of forming by the step 1) and the step of drying by dipping in a solution containing an oxidizing agent (drying step 2). Manufacturing method of electrolytic capacitor.
17. The solid electrolytic capacitor manufactured by the manufacturing method of said 16.
18. 8. The drying apparatus according to any one of 1 to 7, which dries moisture or liquid attached to the electronic device element.
19. 18. An electronic device element manufactured by using the drying apparatus according to 17 above.

In the drying apparatus of the present invention, since the drying air flows through a plurality of ventilation paths having a sectioned shape (preferably the same or similar shape), the amount of air flowing through each ventilation path is uniform, A large number of chemical conversion foils to be capacitor elements can be simultaneously and uniformly dried.
Further, the drying device of the present invention includes a chamber having a sufficient capacity upstream of the ventilation path, and has a structure in which a plurality of ventilation paths having a cross-sectional shape are connected to the chamber. The air volume is uniform, and by placing a capacitor element (chemical conversion foil) in the immediate vicinity of each ventilation path outlet, drying air with a uniform wind speed or volume is formed regardless of the ventilation path installed at the outlet of any ventilation path. Since it supplies to foil, since many chemical conversion foils can be dried uniformly, the solid electrolyte excellent in shape stability with a uniform film thickness can be manufactured efficiently.

  In the drying apparatus of the present invention, the cross-sectional shape of the ventilation path is formed into, for example, a triangle, a rhombus, a trapezoid, a rectangle, a square, a regular hexagon, and the like. It is formed so that the side length of the shape is 1 to 10 times the above-mentioned chemical foil mutual interval, and it is installed on one side or both sides of the chemical foil, and the ventilation speed of the ventilation path is set to 0. By a mode such as controlling in the range of 05 to 1.5 m / s, it is possible to obtain a capacitor element in a dry state with further excellent uniformity.

  Moreover, the drying apparatus of the present invention can have a bypass ventilation path together with an air ventilation path for drying the chemical conversion foil (referred to as a main ventilation path), and a bypass for adjusting the air volume is provided in the bypass ventilation path. Even if the air volume supplied from the blower mechanism is too large by controlling the air volume of the bypass ventilation path to 10 times or less with respect to the volume, the drying air flowing through the main ventilation path is laminar. Thus, a large number of chemical conversion foils can be uniformly dried.

  The drying device of the present invention is a method of manufacturing a solid electrolytic capacitor including a capacitor element in which a solid electrolyte layer is formed on a dielectric film formed on a valve action metal surface. The solid electrolyte layer is immersed in a solution containing a monomer. And drying step (drying step 1) and a drying device immersed in a solution containing an oxidizing agent and drying (drying step 2).

  By using the drying apparatus of the present invention, a solid electrolytic capacitor having a uniform thickness, a high capacity, a dielectric loss (tan δ), a leakage current, and a low defect rate can be obtained. Can be manufactured. Furthermore, by using the drying device of the present invention, the thickness of the capacitor element can be made thinner than before, so that a larger number of capacitor elements can be stacked in the same volume than in the past. As a result, the solid electrolytic capacitor can be reduced in size and capacity.

  As described above, according to the present invention, there is little variation in the element shape, a thin capacitor element can be stably manufactured, the number of capacitor elements in the solid electrolytic capacitor chip can be increased, the capacity can be increased, and the equivalent series resistance can be increased. It is possible to provide a solid electrolytic capacitor element suitable for a multilayer solid electrolytic capacitor having a small variation.

Hereinafter, the present invention will be described with reference to the accompanying drawings.
An example of the solid electrolytic capacitor element manufactured using the drying apparatus of the present invention is shown in FIG.
As shown in the figure, a dielectric film (2) is formed on the surface of the anode substrate (1), and the dielectric film (2) is usually a method for chemical conversion treatment of a porous metal body having a valve action. Etc. are formed. The valve action metal that can be used in the present invention is a simple metal such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, silicon, or an alloy thereof. Further, the porous form may be any form as long as it is a form of a porous molded body such as an etched product of a rolled foil or a fine powder sintered body.

  As the anode substrate (1), a porous sintered body of these metals, plate materials (including ribbons, foils, etc.) surface-treated by etching or the like, wire materials, etc. can be used, but flat and foil-like ones are preferred. . Furthermore, a known method can be used as a method for forming the dielectric film (2) on the surface of the porous metal body (anode substrate) (1). For example, when an aluminum foil is used, an oxide film can be formed by anodizing in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or a sodium salt or an ammonium salt thereof. Moreover, when using the sintered compact of a tantalum powder as an anode board | substrate (1), it can anodize in phosphoric acid aqueous solution and can form an oxide film in a sintered compact.

  Although the thickness of the valve action metal foil varies depending on the purpose of use, for example, a foil having a thickness of about 40 to 300 μm is used. In order to form a thin solid electrolytic capacitor, for example, an aluminum foil having a thickness of 80 to 250 μm is preferably used, and the maximum height of the element provided with the solid electrolytic capacitor is preferably 250 μm or less. Although the size and shape of the metal foil vary depending on the application, a rectangular element having a width of about 1 to 50 mm and a length of about 1 to 50 mm is preferable as a flat element unit, more preferably about 2 to 15 mm in width and about 2 in length. ~ 25 mm.

  Chemical conversion conditions such as chemical conversion liquid and chemical conversion voltage used for chemical conversion on the surface of the metal foil are previously confirmed by experiments and set to appropriate values according to the capacity, withstand voltage, etc. required for the solid electrolytic capacitor to be produced. In this chemical conversion treatment, in order to prevent the chemical conversion liquid from spreading to the portion that becomes the anode of the solid electrolytic capacitor and to ensure insulation from the solid electrolyte (4) (cathode portion) formed in the subsequent step. Generally, masking (3) is provided.

  As a masking material, a general heat resistant resin, preferably a heat resistant resin which can be dissolved or swelled in a solvent or a precursor thereof, a composition comprising inorganic fine powder and a cellulose resin, etc. can be used, but the material is not limited. . Specific examples include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimides and their Examples thereof include derivatives and precursors thereof, and low molecular weight polyimides, polyethersulfones, fluororesins and their precursors are particularly preferable.

  As shown in FIG. 3, for example, a plurality of sheets of the above-described rectangular chemical conversion foil (21) attached to the lower end of a holding body (temporary bar) (22) are aligned and below masking (23). The side is immersed in the chemical conversion liquid (24) to perform chemical conversion treatment. The one subjected to chemical conversion treatment is pulled up, sent to a drying step, and dried by a drying device (30) as shown in FIG. 4 to form the solid electrolyte (4) in FIG.

  This drying step includes a step of drying the solid electrolyte layer by immersing it in a solution containing the monomer (drying step 1) and a step of immersing and drying the solution in a solution containing an oxidizing agent (drying step 2). The drying step 1 is performed in order to supply and fix a monomer on the dielectric surface and the polymer composition. For example, in order to uniformly deposit the monomer on the dielectric surface and on the polymer composition, after impregnating the monomer-containing liquid, the solution is dried for a certain time to evaporate the solvent. The drying apparatus of the present invention is suitably used in the drying step 1 and / or the drying step 2.

  As shown in FIG. 4, the drying device (30) according to a preferred embodiment of the present invention is formed by an assembly of a plurality of ventilation passages (31) divided into cross-sectional shapes, and the plurality of ventilation passages (31). Is a drying device characterized by having a blower mechanism incorporated therein. The cross section of the ventilation path (31) is formed in the same shape so that a uniform amount of air can be obtained in any number of ventilation paths (31). The cross-sectional shape of the ventilation path (31) may be any shape such as a circle or a triangle, but a right triangle, an isosceles triangle, an equilateral triangle, a parallelogram, a rectangle, a rhombus, a trapezoid, a rectangle that can be configured in the same shape and surface. , Squares and regular hexagons are preferable, and the cross-sectional shapes may be different, but they are more preferably the same or similar, and particularly preferably the same. For example, each ventilation path forms a hollow cylindrical passage corresponding to the cross-sectional shape.

  Moreover, it is desirable that the air passing through the ventilation path (31) is a laminar flow. If the air flow is turbulent, the surface roughness of the ventilation path affects the wind speed, so it is difficult to make the wind speed of each ventilation path the same. On the other hand, if the air flow is laminar, the surface roughness of each ventilation path does not affect the wind speed. Therefore, in order to make the wind speed of each ventilation path the same, the laminar flow is desirable. In addition, when the equivalent diameter of the cross-sectional shape of the ventilation path (31) is small, the Reynolds number is lowered, so that a laminar flow area is formed.

  The size of the cross-sectional shape of the ventilation path (31) depends not only on the size and shape of the capacitor elements, but also on the arrangement of the capacitor elements in the drying device, so it cannot be defined unconditionally, but the laminar flow described above is desirable. Considering the ease of manufacturing the ventilation path, the distance between the chemical conversion foils, etc., as shown in FIG. 4, when a large number of chemical conversion foils (21) lowered to the holding body (22) are dried, ventilation is required. The side length L of the cross-sectional shape of the path (31) is suitably 1 to 10 times the mutual distance between the chemical conversion foils.

  For example, chemical conversion foil (21) with a width of 3 mm, a length of 10 mm, and a thickness of 0.1 mm is spaced by 5 mm on one surface of a stainless steel plate (holding body) (22) with a width of 10 mm, a length of 200 mm, and a thickness of 1 mm. When 38 plates are welded in a dough shape and 80 pieces of this holding body (22) are arranged at intervals of 4 mm so that the formed foil faces downward and the welded surfaces are in the same direction are dried (see FIG. 4). ) When the cross-sectional shape of the ventilation path (31) of the drying device (30) is a square, the length of one side of the square is preferably about 5 mm to 50 mm. Or, as shown in FIG. 5, when the cross-sectional shape of the ventilation path (31) is a regular hexagon, if the arrangement of the capacitor elements is the same, the distance between opposite sides of the regular hexagon is about 5 mm to 50 mm. Is preferred.

  The length of the ventilation path (31) is not limited, but if the inscribed circle diameter of the cross-sectional shape and the length of the ventilation path are approximately the same length, it is difficult to make the velocity of the air flowing through each ventilation path the same. Therefore, it is desirable that the length of the ventilation path is not less than five times the inscribed circle diameter of the cross-sectional shape (the value obtained by dividing the ventilation path length by the inscribed circle diameter is not less than 5). For example, when the cross-sectional shape is the above-described square, if the length of one side is 40 mm, the ventilation path may have a length of 200 mm or more. Or when the cross-sectional shape is the above-mentioned regular hexagon, if the distance between the opposing sides is 15 mm, the ventilation path preferably has a length of 60 mm or more. In addition, it is preferable that the several ventilation path (31) which has the divided cross-sectional shape has the same ventilation path length.

  The material used for the ventilation path (31) is not limited. Any material such as stainless steel, aluminum, brass, acrylic resin, and fluororesin may be used. However, stainless steel, aluminum, and the like are desirable because thin plates are readily available, have excellent workability, and are not charged by air flow.

The drying apparatus (30) of the present invention is used in a closed drying container (not shown).
The drying device (30) is installed and used on one side or both sides of the chemical conversion foil (21) lowered to the holding body (22). For example, when the direction of the dry air flow flowing out from the ventilation path (31) is from the top to the bottom of the chemical conversion foil (21), even if the position of the ventilation path (31) is only on the upper side of the chemical conversion foil (21), It may be on the side only or on both the upper and lower sides. In addition, it is excellent and preferable that it exists in both upper side lower side. When the ventilation path (31) is only on the upper side of the chemical conversion foil (21), the speed of the air supplied to the chemical conversion foil (21) is uniform, but the flow of exhaust is restricted by the ventilation path (31). Therefore, the air flowing on the chemical conversion foil surface is not uniform as compared with the case where the ventilation path (31) is installed on both the upper and lower sides. When the ventilation path (31) is only on the lower side of the chemical conversion foil, the reverse is true, and similarly, the velocity of the air flowing on the chemical conversion foil surface is not uniform. If the ventilation path (31) is on both the upper and lower sides, the air that has exited the upper ventilation path will be in a state where the speed is uneven to some extent due to obstacles such as chemical conversion foil, but it will be corrected. In addition, since the amount of air exhausted by the lower ventilation path is limited, a very uniform wind speed can be obtained over the entire area of the chemical conversion foil.

  The drying device (30) of the present invention preferably has a chamber (33) having a sufficiently large capacity on the upstream side (air supply side) of the ventilation path (31). Specifically, for example, it is preferable to have a chamber having a capacity equal to or greater than the amount of dry air per second. In order to make the speed of the air passing through each ventilation path the same, the air needs to have a uniform pressure at the entrance of the ventilation path. When the chamber is not provided, the air pressure at the entrance of each ventilation path is higher in the ventilation path closer to the part that supplies air, and lower in the further ventilation path, so the same amount of air is supplied to each ventilation path after all. I can't.

Since the dimension of the chamber (33) varies depending on the position and shape of the part to which air is supplied and the total amount of air, etc., it cannot be defined unconditionally. It is a duct, the ventilation path is located below, the total cross-sectional area (dry ventilation area) of each ventilation path is 1m x 1m (1.0m ² ), and the total air supply amount is 0.5m ³ / min In some cases, the area of the bottom of the chamber is naturally at least 1 m × 1 m (1.0 m ² ), which is the same as the total cross-sectional area of each ventilation path, and the height of the chamber is preferably 0.5 m or more.

  In addition, as shown in FIG. 4, when drying what arranged the holding body which has many chemical conversion foil, for example, when the arrangement | positioning of chemical conversion foil is the above-mentioned, the ventilation speed of a ventilation path is 0.05-1.5 m /. A range of s is preferred.

  The distance between the chemical conversion foil (21) and the chemical foil holding body (22) and the ventilation path (31) is not particularly defined, but the smaller the better. When this interval becomes large, air flows out from the interval, resulting in a difference in the air speed between the central portion and the end portion of the drying device. Therefore, it is desired that the distance is smaller than the distance between the chemical conversion foils. For example, when the chemical foils are arranged as described above, the distance between the stainless steel plate (holding body) (22) and the upper ventilation path is preferably 4 mm or less, more preferably 1 mm or less. Similarly, the distance between the chemical conversion foil (21) and the lower ventilation path is preferably 4 mm or less, more preferably 1 mm or less.

  The amount of air passing through the ventilation path (31), that is, the wind speed, varies depending on the type of solvent, the distance between the chemical conversion foils, and the like. Wind speed is preferred. When the air flow from the blower mechanism is too large to make the air flow through the ventilation path into a laminar flow, the ventilation path from the supply side chamber (33) to the conversion foil (the main ventilation path for drying the conversion foil) ), A bypass ventilation path (34) may be provided. The bypass ventilation path may be connected to a chamber on the exhaust side.

  The size and shape of the bypass ventilation path (34) are not particularly defined, but the amount of air B passing through the bypass ventilation path (the amount of air not contributing to drying of the chemical conversion foil) is the amount of air A passing through the main ventilation path (chemical conversion foil). 10 times or less (B / A ≦ 10) is appropriate. If the bypass ventilation amount B exceeds 10 times, it becomes difficult to control the temperature and humidity, and the temperature and humidity of the air passing through the bypass ventilation path may be different from the temperature and humidity of the air passing through the main ventilation path. When providing a bypass ventilation path, it is desirable to arrange a damper (36) for adjusting the air volume in the middle of the bypass ventilation path so that the ventilation volume can be adjusted.

  The drying device (30) of the present invention preferably has a sensor (35) for measuring the temperature and / or humidity of the blown air in either or both of the main ventilation path (32) and the bypass ventilation path (34). Thus, the atmosphere of the blown air can be controlled. A member in which air whose temperature and / or humidity is controlled flows into the ventilation path through a chamber (33) connected to the inlet of the ventilation path, flows out from the outlet of the ventilation path in a laminar state, and is installed at the outlet of the ventilation path; That is, the chemical conversion foil used as a capacitor element is dried.

  As described above, for example, in a solid electrolytic capacitor, a step of drying a solid electrolyte layer by immersing it in a solution containing a monomer (drying step 1) and a step of immersing and drying in a solution containing an oxidizing agent (drying step 2). It is manufactured through. The drying temperature in the drying step 1 varies depending on the type of the solvent, but is generally about 0 ° C. or higher to the boiling point of the solvent. The drying time also varies depending on the type of solvent, but is generally 5 seconds to 15 minutes, for example, within 5 minutes for alcohol solvents. By using the drying apparatus of the present invention, the monomer can be uniformly deposited on the surface of the dielectric, and contamination during immersion in the oxidant-containing liquid in the next step can be reduced.

  Using the drying apparatus of the present invention, the chemical conversion foil is dried to uniformly adhere the monomer (drying step 1), and then immersed in the oxidant-containing liquid. After being immersed in the oxidant-containing liquid, it is pulled up and dried in the air for a predetermined time using the drying apparatus of the present invention (drying step 2). In this drying step 2, the monomer on the surface of the chemical conversion foil undergoes oxidative polymerization under a certain temperature range. The temperature maintained in the air varies depending on the type of monomer, but may be, for example, 5 ° C. or lower for pyrrole and about 30 to 60 ° C. for thiophene. The oxidative polymerization time in the drying step 2 varies depending on the adhesion amount of the monomer, the concentration and viscosity of the monomer and oxidant-containing liquid, and thus cannot be specified unconditionally. However, generally, the polymerization time can be shortened by reducing the adhesion amount per one time. In addition, if the amount of adhesion at one time is increased, a longer oxidative polymerization time is required.

  In the drying steps 1 and 2, by using the drying apparatus of the present invention, the oxidant-containing liquid adhering to the dielectric surface and the polymer composition is dried at a uniform rate. A uniform solid electrolyte layer having the same film thickness is formed in the drying apparatus.

  The preferable formation process of the solid electrolyte using the drying apparatus of the present invention is that the chemical conversion foil is immersed in a solution containing a monomer, dried in the drying apparatus of the present invention in the drying process 1, immersed in an oxidizing agent-containing liquid, and dried. The process of oxidative polymerization in the drying apparatus of the present invention in step 2 is repeated 3 times or more, preferably 8 to 30 times as one cycle, and a high quality solid electrolyte layer is formed by repeating this dipping and drying. I can do it.

  Specifically, as shown in the examples described later, an aluminum foil having a dielectric oxide film is impregnated in an isopropyl alcohol (IPA) solution of 3,4-ethylenedioxythiophene (EDT), for example. After almost removing IPA by drying with the drying apparatus of the present invention, it was impregnated with an aqueous solution of about 20% by mass of an oxidizing agent (ammonium persulfate) and then dried at about 40 ° C. for 10 minutes with the drying apparatus of the present invention. By repeating the steps, a polymer of poly (3,4-ethylenedioxythiophene) can be obtained. In addition, after forming a solid electrolyte layer using the drying apparatus of this invention, you may wash | clean using water, alcohol, ketones, or these liquid mixture.

  It is preferable to provide a conductor layer on the conductive polymer composition layer (4) formed through the above steps in order to improve electrical contact with the cathode lead terminal. The conductor layer is formed by, for example, a conductive paste, plating, vapor deposition, or a conductive resin film. The solid electrolytic capacitor element thus obtained is usually connected to a lead terminal and applied to, for example, a resin product, a resin case, a metal outer case, a resin dipping, etc. Manufactured. Furthermore, it is useful not only for capacitor elements but also for uniform drying of device elements used in various electronic devices, and can contribute to a reduction in the defective rate of each device element.

  The present invention will be described in more detail below with typical examples. Note that these are merely illustrative examples, and the present invention is not limited thereto.

Example 1
Aluminum conversion foil () is hereinafter referred to as conversion foil. ) Was cut into a minor axis direction of 3 mm and a major axis direction of 10 mm, and a polyimide solution having a width of 1 mm was applied on both sides to form a mask so as to divide the major axis direction into 4 mm and 5 mm portions. A 3 mm × 4 mm portion of this chemical conversion foil was formed into a cut portion by applying a voltage of 4 V with a 10 mass% ammonium adipate aqueous solution to form a dielectric oxide film. Next, a 3 mm × 4 mm portion of the chemical conversion foil was impregnated for 5 seconds with an isopropyl alcohol (IPA) solution in which 3,4-ethylenedioxythiophene was dissolved, and this was dried using the drying apparatus of the present invention. (Drying process 1). The cross-sectional shape of the ventilation path of this drying apparatus is shown in FIG. As shown in the figure, this ventilation path has a regular hexagonal cross section, and the distance between the opposing sides is 9.5 mm (manufactured by Nippon Aircraft Industry Co., Ltd., model AL3 / 8-5052-.002, width 100 mm). . Then, the said conversion foil was immersed in ammonium persulfate aqueous solution. Subsequently, the chemical conversion foil was placed at the top and bottom of the drying apparatus of the present invention (shown in FIG. 4), and dried at 40 ° C. for 10 minutes (drying step 2) to perform oxidative polymerization. This dipping process and polymerization process were repeated to form a solid electrolyte layer of a conductive polymer on the outer surface of the aluminum foil. The finally produced polymer (3,4-ethylenedioxythiophene) was washed in warm water and then dried to form a solid electrolyte layer.

Using a film thickness meter (manufactured by Peacock: digital dial gauge DG-205, accuracy 3 μm), the thickness was measured by slowly sandwiching the aluminum foil between the measurement portions of the film thickness meter. The average film thickness of 120 elements was 140 μm, and the standard deviation was 7 μm.
Next, a 3 mm × 4 mm portion on which the solid electrolyte layer is formed is immersed in an ammonium adipate solution, and an anode contact is provided on the portion of the valve metal foil where the solid electrolyte layer is not formed, and a voltage is applied. Re-formed.

  Next, a carbon paste and a silver paste were attached to the portion where the conductive polymer composition layer of the aluminum foil was formed, and the four aluminum foils were laminated, and the cathode lead terminals were connected. Moreover, the anode lead terminal was connected to the part in which the conductive polymer composition layer was not formed by welding. Furthermore, after sealing this element with an epoxy resin, a rated voltage (2 V) was applied at 125 ° C. and aging was performed for 2 hours, thereby completing a total of 100 capacitors.

  With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

(Example 2)
In the drying apparatus of the present invention, the cross-sectional shape of the ventilation path is a regular hexagon and the distance between opposing sides is 6.35 mm (manufactured by Nippon Aircraft Industry Co., Ltd., model: AL1 / 4-5052-.001, width 100 mm, cross section A total of 100 capacitors were completed in the same manner as in Example 1 except that the shape shown in FIG. 7 was used. With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

(Example 3)
In the drying apparatus of the present invention, a total of 100 capacitors were obtained in the same manner as in Example 1 except that the cross-sectional shape of the ventilation path was square and the length of one side was 12 mm (material: SUS304, plate thickness 0.2 mm). Was completed. With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

Example 4
In the drying apparatus of the present invention, a total of 100 pieces were obtained in the same manner as in Example 1 except that the cross-sectional shape of the ventilation path was a regular triangle and the length of one side was 12 mm (material: SUS304, plate thickness 0.2 mm). The capacitor was completed. With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

(Example 5)
The conversion foil is impregnated with isopropyl alcohol (IPA) solution in which 3,4-ethylenedioxythiophene is dissolved for 5 seconds, and this is dried indoors for 5 minutes (that is, drying step 1 is performed without using the drying apparatus of the present invention). Carried out). Next, after this chemical conversion foil was immersed in an aqueous ammonium persulfate solution for 5 seconds, the same drying apparatus as in Example 1 was placed up and down and dried at 40 ° C. for 10 minutes (that is, the drying process using the drying apparatus of the present invention). 2), oxidative polymerization was carried out, and a total of 100 capacitors were completed in the same manner as in Example 1. With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

(Comparative Example 1)
The conversion foil was impregnated with a 2.0 mol / L isopropyl alcohol (IPA) solution in which 3,4-ethylenedioxythiophene was dissolved for 5 seconds, dried indoors for 5 minutes, and immersed in an aqueous ammonium persulfate solution for 5 seconds. After that, a total of 100 capacitors were completed in the same manner as in Example 1 except that it was dried at 40 ° C. for 10 minutes using a commercially available drying furnace (different from the drying apparatus of the present invention) and subjected to oxidative polymerization. I let you. With respect to these 100 capacitor elements, the initial characteristics were measured for capacity and loss factor (tan δ × 100%), equivalent series resistance (ESR), and leakage current at 120 Hz. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the number of defects when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

  Since the device element for electronic equipment such as the capacitor element according to the present invention has a uniform thickness and excellent electrical characteristics, it can be used in a wide range of fields such as home appliances, computers, communication equipment, in-vehicle parts, industrial equipment, etc. Can be used.

Cross-sectional view of a solid electrolytic capacitor using a capacitor element Schematic cross section of capacitor element Explanatory drawing which shows the immersion state of chemical conversion foil Perspective view showing dry state of chemical conversion foil Cross section of the ventilation path (part) of the drying device Sectional drawing of the ventilation path (part) of the drying apparatus in Example 1 Sectional drawing of the ventilation path (part) of the drying apparatus in Example 2

Explanation of symbols

1: Anode substrate (metal foil)
2: Dielectric film 3: Masking 4: Solid electrolyte 5: Conductor layer 11: Capacitor element 11a: Cathode part 11b of capacitor element: Anode part 13: Cathode lead part 14: Anode lead part 15: Bonding of anode Part 16: exterior resin 21: chemical conversion foil 22: holding body (stainless steel plate)
23: Masking 24: Chemical conversion solution 30: Drying device 31: Ventilation path 32: Main ventilation path 33: Chamber 34: Bypass ventilation path 35: Sensor 36: Damper

Claims (19)

  A drying apparatus comprising a blower mechanism in which a plurality of ventilation paths having a sectioned section shape are included.   The drying apparatus according to claim 1, wherein the cross-sectional shapes are the same or similar.   2. A blower mechanism comprising a chamber having a capacity of at least a dry air volume per second on an air supply side and / or an air recovery side of a plurality of ventilation paths having a sectioned section. 2. The drying apparatus according to 2.   The drying apparatus according to any one of claims 1 to 3, further comprising a blower mechanism in which a plurality of ventilation paths connected to the chamber and having a sectioned section have the same length.   The drying apparatus according to any one of claims 1 to 4, further comprising a blower mechanism having a plurality of ventilation paths whose length of the ventilation path is five times or more the inscribed circle diameter of the ventilation path cross-sectional shape.   The drying apparatus according to any one of claims 1 to 5, wherein a cross-sectional shape of the ventilation path is a right triangle, an isosceles triangle, a regular triangle, a parallelogram, a rectangle, a rhombus, a trapezoid, a rectangle, a square, or a regular hexagon. .   Air whose temperature and / or humidity is controlled flows into the ventilation path through a chamber connected to the inlet of the ventilation path, flows out from the outlet of the ventilation path in a laminar state, and dries the member installed at the outlet of the ventilation path. Item 7. The drying apparatus according to any one of Items 1 to 6.   The drying apparatus according to any one of claims 1 to 7, wherein a solution attached to the chemical conversion foil to be a capacitor element is dried.   It is an apparatus which dries the solution adhering to the some conversion foil lowered | hung to the holding body, Comprising: The side length of the cross-sectional shape of a ventilation path is 1 to 10 times the said formation foil mutual space | interval. The drying apparatus according to any one of the above.   The drying apparatus according to any one of claims 1 to 9, wherein the drying apparatus is disposed on one side or both sides of the plurality of conversion foils lowered to the holding body and dries the solution attached to the conversion foil.   The drying device according to any one of claims 1 to 10, wherein the ventilation speed of the ventilation path is 0.05 to 1.5 m / s.   The drying apparatus according to any one of claims 1 to 11, which has a bypass ventilation path as well as an air ventilation path for drying the solution adhering to the chemical conversion foil.   The drying apparatus according to claim 12, wherein an air volume adjusting damper is provided in the bypass ventilation path.   The drying apparatus according to claim 12 or 13, wherein the air volume of the bypass ventilation path is 10 times or less of the air volume of the air ventilation path for drying the solution adhering to the chemical conversion foil.   13. A sensor for measuring the temperature and / or humidity of the blown air is provided in either or both of the air ventilation path and the bypass ventilation path for drying the solution adhering to the chemical conversion foil to control the atmosphere of the blown air. The drying apparatus in any one of -14.   In a method for manufacturing a solid electrolytic capacitor including a capacitor element in which a solid electrolyte layer is formed on a dielectric film formed on a valve action metal surface, the step of drying by immersing the solid electrolyte layer in a solution containing a monomer (drying) In the case of forming by step 1) and a step of drying by dipping in a solution containing an oxidizing agent (drying step 2), drying is performed using the drying apparatus according to any one of claims 1 to 15. A method for producing a solid electrolytic capacitor.   The solid electrolytic capacitor manufactured with the manufacturing method of Claim 16.   The drying apparatus according to any one of claims 1 to 7, wherein moisture or liquid adhering to the electronic device element is dried. The electronic device element manufactured using the drying apparatus of Claim 17.

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