JP2007031488A - Method for producing composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a composite material with reduced fluctuation in thickness of a polymer layer, in particular to provide a method for producing a stacked solid electrolytic capacitor with reduced fluctuation of film thickness of elements, low in happening of fault such as element deviation in stacking and hard to produce an unsealed product in sealing. <P>SOLUTION: The invention relates to the method for producing the composite material by repeating a process attaching a liquid containing a monomer on a plurality of substrates and a process sequentially soaking the substrates in a liquid containing an oxidant, wherein the sequence of soaking the substrate attached with liquid containing the monomer is changed and repeated. The invention relates to the method for producing the stacked solid electrolytic capacitor which utilizes above method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a composite material having a polymer layer on a substrate surface, in particular, a method for producing a solid electrolytic capacitor element having a conductive polymer as a polymer layer, and a capacitor element produced by this method. Related to the capacitor.

  Composite materials having a polymer layer on the surface of a substrate are used in various fields. For example, in recent years, with the digitization of electrical equipment and the speeding up of personal computers, small and high-capacity capacitors and low-impedance capacitors in the high-frequency region are required, and conductive polymers having electronic conductivity are used as solid electrolytes. Solid electrolytic capacitors have been proposed.

  A basic element (6) of a solid electrolytic capacitor is generally formed by forming a dielectric oxide film layer (2) on an anode substrate (1) made of a metal foil having a large specific surface area that has been etched as shown in FIG. A solid semiconductor layer (hereinafter referred to as a solid electrolyte) (3) is formed as an electrode facing the outside, and a conductor layer (4) such as a conductive paste is preferably formed. Usually, in order to ensure insulation between the solid electrolyte (3) (cathode portion) and the anode substrate (1), a masking layer (5) is further provided, and electrodes are appropriately added.

  In general, an electrolytic oxidation polymerization method and a chemical oxidation polymerization method are known as methods for forming a conductive polymer 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, there is disclosed a method of forming a solid electrolyte having a layered structure by alternately repeating a step of immersing an anode substrate in a solution containing a monomer and a step of immersing in a solution containing an oxidizing agent (Patent Document 1: Patent) No. 3187380). According to this method, it is possible to produce a solid electrolytic capacitor having a high capacity, low impedance, and excellent heat resistance by forming a solid electrolyte layer having a layered structure with a film thickness of 0.01 to 5 μm. Since the space between the layers of the layered structure portion forming the layer is large, further reduction in the thickness of the entire solid electrolyte layer is required as an element for a multilayer capacitor in which a plurality of capacitor elements are stacked.

  Further, as a method of 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 in an oxidant solution. A method of repeating a cycle of polymerizing and washing an oxidant and then drying is disclosed (Patent Document 2: JP-A-9-306788).

  Thus, since any manufacturing method includes the operation of immersing and pulling up the solid electrolytic capacitor element conductor (anode substrate) in the monomer-containing solution and the oxidant-containing solution, it is necessary to efficiently perform the dipping and lifting operations. For this reason, normally, in the manufacture of a solid electrolytic capacitor element, a plurality of elements are simultaneously processed using a support plate called a temporary bar and a frame called a handling frame capable of holding a plurality of support plates. In addition, since the time related to the polymerization reaction is generally longer than the time related to the immersion operation, a plurality of handling frames are prepared, the immersion operation is performed in order, and sequentially put into the reaction furnace within the same time. It is devised to obtain a large number of solid capacitor elements.

Japanese Patent No. 3187380 JP-A-9-306788

  In order to obtain a solid electrolytic capacitor having a predetermined capacity from the obtained element, normally, as shown in FIG. 2, a plurality of capacitor elements (6) are laminated and an anode lead wire (7) is joined to an anode terminal. The cathode lead wire (8) is connected to the conductor layer including the solid electrolyte layer, and the whole is completely sealed with an epoxy resin (9) or the like to obtain a capacitor component. For this reason, if the thickness of the solid electrolyte layer (3) of each capacitor element is non-uniform, problems such as element displacement occur at the time of stacking, or the thickness after stacking becomes too thick. There is a problem that it leads to unsealing. Therefore, it is necessary to control the thickness of the solid electrolyte layer by closely controlling the polymerization conditions of the solid electrolyte in the cathode portion of the capacitor element. However, in the capacitor element manufactured by the method using the temporary bar and the handling frame, the thickness of the solid electrolyte layer (4) is sufficiently uniform between the handling frames even though it is manufactured in the same batch. In some cases, there was a need for a solution.

  Thus, in a composite material having a polymer layer on the substrate surface, it is required to form the polymer layer uniformly and efficiently. In particular, in a multilayer solid electrolytic capacitor that is strongly demanded to have a low profile, it is necessary to uniformly form a polymer layer on the surface of the element while efficiently producing the capacitor element. Accordingly, an object of the present invention is to solve the above-described problems and provide a capacitor element suitable for a composite material having a polymer layer having a small thickness variation, particularly a multilayer solid electrolytic capacitor, and a method for manufacturing the capacitor element. It is in.

  As a result of intensive studies in view of the above problems, the present inventors have repeatedly conducted a process of adhering a monomer-containing liquid to a plurality of base materials and then sequentially immersing them in an oxidizing agent-containing liquid. In the method for producing a composite material for forming a composite material, it is possible to obtain a composite material having a polymer layer with a small variation in thickness by repeating the immersion sequence of the substrate to which the monomer-containing liquid is adhered, The method is suitable for a method of manufacturing a solid electrolytic capacitor element such as a multilayer type, and in particular, a plurality of solid capacitor element conductors set on a handling frame are sequentially immersed in a solution containing a monomer and a solution containing an oxidizing agent. The present invention has been found to be useful in a method for producing a solid electrolytic capacitor having a step of pulling up.

That is, the present invention relates to the following composite material manufacturing method, solid electrolytic capacitor element manufacturing method, solid electrolytic capacitor element and solid electrolytic capacitor manufactured by the manufacturing method, and a manufacturing apparatus employing the manufacturing method.
1. In a method for manufacturing a composite material in which a polymer layer is formed on a substrate surface by repeatedly attaching a monomer-containing solution to a plurality of substrates and then sequentially immersing the substrate in an oxidizing agent-containing solution, the monomer-containing solution is attached. A method for producing a composite material, characterized in that the immersion is repeated by changing the immersion order of the base material.
2. 2. The method for producing a composite material according to 1 above, wherein the immersion order of the base material is changed every time the process is repeated.
3. 3. The method for producing a composite material according to 1 or 2, wherein the immersion order is changed by randomly rearranging the immersion order.
4). 3. The method for producing a composite material according to 1 or 2, wherein the immersion order is changed by shifting the immersion order.
5. 5. The method for producing a composite material according to any one of 1 to 4, wherein a part or all of the oxidant-containing liquid is exchanged with a new liquid in the middle of any of the repeating steps.
6). The manufacturing method of the composite material in any one of said 1-4 which replace | exchanges part or all of an oxidizing agent containing liquid for a new liquid after completion | finish of one of the said repeating processes before the next repeating process.
7). The manufacturing method of the composite material in any one of Claims 1-6 which hold | maintain the some base material to which the monomer containing liquid was made to adhere to several support members, and perform the said immersion operation for every support member.
8). 8. The method for producing a composite material according to any one of 1 to 7, wherein the base material is a valve metal having a porous layer on the surface, and the monomer is a monomer of a conductive polymer.
9. 9. The method for producing a solid electrolytic capacitor element as described in 8 above, wherein the composite material to be produced is a solid electrolytic capacitor element.
10. 10. A solid electrolytic capacitor element produced by the method described in 9 above.
11. 11. A solid electrolytic capacitor using the solid electrolytic capacitor element as described in 10 above.
12 11. A multilayer solid electrolytic capacitor obtained by laminating a plurality of capacitor elements as described in 10 above.
13. A solid electrolytic capacitor manufacturing apparatus that employs the manufacturing method according to 9 above.

  According to the present invention, it is possible to stably and efficiently produce a composite material having a small variation in the thickness of the polymer layer, particularly a capacitor element having a small variation in the thickness of the solid electrolyte layer. Therefore, it is possible to provide a solid electrolytic capacitor element suitable for a multilayer solid electrolytic capacitor that is less likely to be unsealed during sealing.

  The present invention relates to a method for producing a composite material in which a monomer layer is adhered to a plurality of substrates and then sequentially immersed in an oxidizing agent-containing solution to form a polymer layer on the substrate surface. It repeats by changing the immersion order of the base material to which the containing liquid is adhered. That is, in the conventional method, as shown schematically in FIG. 3, the base materials 11 are transported in the processing facility in a fixed order (a => b => c => d => e => f in the figure). (It is conveyed from the left to the right in the figure), and is immersed in the oxidant-containing liquid 12 in the middle thereof. This process is cyclic, and each base material 11 is repeatedly immersed in the oxidant-containing liquid 12 in a fixed order (second stage in FIG. 3). Although up to the second round is shown here, the following immersion is similarly performed in the order of a => b => c => d => e => f.

  On the other hand, in this invention, the said repetition is performed changing the immersion order of a base material. That is, as illustrated in FIG. 4, a different order (c = in the figure) from the immersion order of the substrate in the first round (in the figure, a => b => c => d => e => f). > f => a => e => b => d) and the second round of immersion is performed. Although up to the second round is shown here, the same applies to the following.

  The base material immersion sequence may be changed every time the process is repeated, that is, each time a predetermined number of base materials (a to f in FIG. 4) are processed once, or in the same number of times. The order may be changed after repeating the process in. For example, in the example of FIG. 4, the immersion order may be changed in each process cycle thereafter as in the first and second rounds. Alternatively, repetitions in the same immersion order and repetitions in different immersion orders may be mixed, such as changing the immersion order in the second and subsequent rounds by changing the immersion order in the first and second rounds. In general, when the dipping process in which a predetermined number of base materials are treated as one set is repeated a plurality of times, it is sufficient that at least one of the processes has a dipping order different from the other processes.

However, preferably, the order is set so that each base material is immersed in the oxidizing agent-containing liquid on average. That is, when the dipping process is repeated n times in the example of FIG. 4, the order in which the base materials a to f are dipped in the k-th (1 ≦ k ≦ n) repeating process is represented by a _{k to} f _k , respectively. (where each? a _k, etc. represent a ₁ + ··· + a _n, etc..) Σa _k ~Σf _k is possible equal, i.e., to be included within a narrow range.

  Such a condition can be satisfied, for example, by rearranging the immersion order at random. In addition, the dipping order is shifted, for example, the next step after a => b => c => d => e => f is performed in the order of b => c => d => e => f => a. Also good. In the present application, “shifting the dipping order” means that the dipping order of the substrate is shifted by 1 as a whole as in the above example, and a => b => c => d => e => f This includes the shift by two (or more), such as performing the next step in the order of c => d => e => f => a => b. However, these are merely examples, and other rearrangement methods may be adopted as long as each substrate is averagely immersed in the oxidant-containing liquid in the above sense.

  Furthermore, in a preferred embodiment of the present invention, part or all of the oxidant-containing liquid is replaced with a new liquid during any of the above repeating steps. Or you may perform replacement | exchange to a new liquid after the completion | finish of one of the said repeating processes, and before the next repeating process. The exchange may be performed every time for each step, or may be performed every several times. In the case of performing partial exchange, the ratio is not particularly limited. For example, the ratio is 5% or more, preferably 10% or more of the total amount of the immersion liquid.

In the present invention, the immersion sequence can be changed by exchanging part or all of the oxidizing agent-containing liquid.
For example, when processing 6 substrates of a => b => c => d => e => f, when the processing of 5 substrates other than 6, for example, 5 substrates is completed (ie, base If the oxidant-containing liquid is exchanged between the material e and the base material f), it can be regarded that a new process is started from f. In other words, when the oxidant-containing liquid is replaced when the processing of the five substrates is finished,
1st round a => b => c => d => e => * => f
2nd round a => b => c => d => * => e => f
3rd round a => b => c => * => d => e => f
4th round a => b => * => c => d => e => f
...
(In the above permutation, * indicates replacement with a new liquid.) Since the liquid composition changes discontinuously due to the replacement of the new liquid, the first time a => b => c = > d => e => *
2nd f => a => b => c => d => *
3rd e => f => a => b => c => *
4th d => e => f => a => b => *
...
Thus, the immersion order of the base material is shifted by 1 each time. In the present application, “changing the immersion order” includes such a mode. In this case as well, it is not always necessary to exchange the new liquid every certain number of times, and the exchange interval is arbitrary. In general, when the dipping step with one cycle of treatment of x substrates is repeated, treatment of at least one of the steps (that is, treatment of less than x or more than x substrates) The liquid may be exchanged at the time of completion. In the case where the immersion order is actually changed in the repetition process as described above, the liquid may be exchanged after any of the repetition processes and before the next repetition process.

Although not shown in FIG. 4, various processes may be performed after the end of any one of the repeating steps and before the next repeating step. For example, it is preferable to attach the monomer-containing liquid before the immersion treatment, and after the immersion treatment, it is preferable to put in a polymerization promotion furnace. The adhesion of the monomer-containing liquid includes an arbitrary adhesion method such as immersion in the monomer-containing liquid, application of the monomer-containing liquid, and spraying of the monomer-containing liquid.

  In the present invention, a plurality of base materials to which a monomer-containing liquid is attached can be held on a plurality of support members, and the dipping operation can be performed for each support member. This aspect corresponds to the above description and a to f shown as the base material in FIG. 4 replaced with aggregates of base materials held by the support members.

The composite material produced in the present invention is not particularly limited as long as it has a polymer layer formed by oxidative polymerization on the substrate, and the present invention can be applied regardless of the type of substrate or monomer. The use is not particularly limited as long as it is advantageous to combine with a polymer layer by oxidative polymerization.
However, the present invention is particularly useful in a method for producing a composite material, particularly a solid electrolytic capacitor element, in which the base material is a valve metal having a porous layer on the surface and the monomer is a conductive polymer. That is, as described above, in the manufacture of solid electrolytic capacitor elements, a plurality of capacitor element manufacturing substrates are held on a support plate called a temporary bar, and further called a handling frame that can hold a plurality of support plates. In this way, the present invention uses a plurality of temporary bars or handling frames as described above, and continuously attaches monomer-containing materials and immerses them in oxidant-containing solutions. This is particularly useful in a method for producing a solid electrolytic capacitor that is operated and charged into a polymerization accelerating furnace. This aspect corresponds to the above description and a to f shown as the base material in FIG. 4 replaced with a temporary bar or a handling frame (accurately, a collection of base materials held by these), respectively.

  Typically, a base for a solid electrolytic capacitor element is attached to a temporary bar, and a plurality of handling frames that hold a plurality of temporary bars are used, and a monomer-containing liquid is sequentially applied to the base material held by these handling frames. In a method for manufacturing a solid electrolytic capacitor in which a polymer layer is formed by repeating a plurality of steps including an operation of adhering, immersing in an oxidant-containing solution, and putting it in a polymerization accelerating furnace. Immerse in the containing solution.

The change of the order is as described above, and the order of the handling frames may be changed every time the process is repeated, and the base material may be immersed, or the order of the handling frames is changed every appropriate number of times. Dipping may be performed. Further, the order may be changed by rearranging the handling frames at random, or by changing the order of the handling frames for each process. Moreover, you may substantially shift the order of a handling frame by replacing | exchanging a part or all of oxidizer containing liquid to a new liquid in the middle of either of the said repeating process. Alternatively, after actually changing the order of the handling frames, a part or all of the oxidant-containing liquid may be replaced with a new solution after the end of any one of the repeating steps and before the next repeating step.

  In the present invention, the number of capacitor element substrates (hereinafter, also simply referred to as “elements”) that are processed in one step or until the oxidant solution is replaced is not particularly limited depending on the type of each solution and the processing conditions. However, it is generally between 5000 and 100000 elements, more preferably between 50000 and 150,000 elements. If the number of elements to be processed before the exchange / mixing of the oxidant solution is small, a large amount of oxidant is required per element, and if the number of elements is too large, the oxidant solution is likely to deteriorate.

  The reason why the present invention has a particularly excellent effect in the production of a solid electrolytic capacitor element is that (1) the assembly of base materials held in a plurality of handling frames is sequentially immersed in a monomer-containing solution and an oxidant-containing solution. Therefore, the content of monomers and oligomers mixed as impurities in the oxidizer immersion tank will increase. (2) The immersion order of the handling frame will not be changed every time in the conventional method. The effect of impurities in the oxidant solution increases cumulatively, and the amount and thickness of the solid electrolyte between the capacitor element held in the first handling frame and the capacitor element held in the last handling frame in each cycle. The variation in the quantity and quality of the solid electrolyte layer between capacitor elements, such as non-uniformity, (3) Changing the order of the grayed frame, and that such a portion or the total amount of the oxidizing agent solution may be controlled by replaced with new chemical is considered.

That is, in the conventional method, hundreds to thousands of elements to be immersed are packed in one supporting frame, and several tens of the supporting frames are continuously immersed in the solid electrolyte forming operation. Usually, the solid electrolyte forming operation is repeated several times to several tens of times from this immersion. By carrying out the immersion treatment with several tens of support frames, the amount of monomer mixed in the oxidizer solution gradually increases, and accordingly, the elements of the end handling frame compared to the start handling frame. The amount of adhesion to will increase. For this reason, the element processed with the handling frame of the tail side becomes relatively thick. The present invention eliminates or prevents this non-uniformity over time, and changes the order of the handling frames and replaces part or all of the oxidant solution with a new solution regardless of the passage of time. Uniform the amount of monomer adhering to. However, in the present invention, the layer thickness is suppressed as a whole, and the effect of the present invention is not limited to the above mechanism.

  The conductor for the anode substrate of the solid electrolytic capacitor element is generally a metal having a valve action. The metal having a valve action 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 etching product of a rolled foil or a fine powder sintered body. Furthermore, a known method can be used as a method of forming a dielectric oxide film on the surface of the porous metal body. 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, it can anodize in phosphoric acid aqueous solution and can form an oxide film in a sintered compact.

The solid electrolyte is formed as a cathode. For this purpose, the immersion is usually performed following the adhesion of the monomer-containing solution to the oxidant-containing solution. The adhesion of the monomer-containing solution and the components of each solution are not particularly limited as long as they are suitable for the formation of a fixed electrolyte, but are typically as follows.
It is immersed in a solution containing the monomer and then dried, and the monomer is supplied onto the dielectric surface and the polymer composition. Further, in order to uniformly deposit the monomer on the dielectric surface and the polymer composition, after impregnating the monomer-containing liquid, the solvent is allowed to evaporate by being left in the air for a certain period of time. This condition varies depending on the type of solvent, but is generally performed at a temperature from 0 ° C. or higher to the boiling point of the solvent. The standing time varies depending on the type of the solvent, but it is generally about 5 seconds to 15 minutes, for example, within 5 minutes for alcohol solvents. By providing this standing time, the monomer can uniformly adhere to the surface of the dielectric, and contamination during immersion in the oxidizing agent-containing liquid in the next step can be reduced.

  The dipping time of the oxidant solution applied as the next step may be a time sufficient for the oxidant component to adhere on the dielectric surface of the metal foil substrate, usually less than 15 minutes, preferably from 0.1 seconds to 10 minutes, more preferably 1 second to 7 minutes.

Examples of the oxidizing agent include an aqueous oxidizing agent and an organic solvent oxidizing agent. Examples of aqueous oxidizing agents include peroxodisulfuric acid and its Na salt, K salt, NH ₄ salt, cerium (IV) nitrate, cerium (IV) ammonium nitrate, iron (III) sulfate, iron (III) nitrate, iron chloride (III) etc. are mentioned. Examples of the organic solvent-based oxidizing agent include ferric salts of organic sulfonic acids such as iron (III) dodecylbenzenesulfonate and iron (III) p-toluenesulfonate.

  Examples of the solvent for the oxidant solution include ethers such as tetrahydrofuran (THF), dioxane, and diethyl ether; ketones such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, benzonitrile, N-methylpyrrolidone (NMP), dimethyl sulfoxide ( DMSO) and other aprotic polar solvents; alcohols such as methanol, ethanol and propanol; water or a mixed solvent thereof can be used. Preferably, water, alcohols or ketones or a mixed system thereof is desirable.

  In addition, the density | concentration of an oxidizing agent solution is although it does not specifically limit, 5-50 mass% is preferable, and the temperature of an oxidizing agent solution has preferable -15-60 degreeC.

  The conductive polymer forming the solid electrolyte is a polymer of an organic polymer monomer having a π-electron conjugated structure, and the degree of polymerization is 2 or more and 2000 or less, more preferably 3 or more and 1000 or less, and further preferably 5 or more and 200 or less. . As specific examples, a conductive polymer containing a structure represented by a compound having a thiophene skeleton, a compound having a polycyclic sulfide skeleton, a compound having a pyrrole skeleton, a compound having a furan skeleton, a compound having an aniline skeleton, or the like as a repeating unit. Is mentioned.

  As the monomer, a compound having a thiophene skeleton or a polycyclic sulfide skeleton is preferable. The polymerization conditions and the like of these compounds are not particularly limited, and can be easily carried out after confirming preferable conditions in advance by simple experiments.

  In addition, a compound selected from the above monomer group may be used in combination to form a solid electrolyte as a copolymer. The composition ratio of the polymerizable monomer at that time depends on the polymerization conditions and the like, and the preferred composition ratio and polymerization conditions can be confirmed by a simple test.

  On the conductive polymer composition layer thus formed, it is preferable to provide a conductor layer 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 laminated alone (for example, as shown in FIG. 2) (but not limited to this form), and connected to a lead terminal, for example, a resin mold, a resin case, Capacitor products for various applications can be made by applying a metal outer case or resin dipping.

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

Example 1
(a) Attachment of conductor to support plate An aluminum conversion foil (thickness: 100 μm) formed by subjecting the surface of the aluminum foil to chemical conversion treatment by a conventional method was cut out so that one piece had a rectangular shape of 3 mm × 10 mm. The 30 sheets of the formed foil are spaced from each other by 4 mm so that the length from the end on the short side (3 mm) side to 2 mm overlaps the stainless steel support plate (224 mm × 15 mm × 1.0 mm (made by SUS304), hereinafter referred to as temporary bar). And welded in a row. Next, with respect to each chemical conversion foil, a fluororesin having a width of 1 mm was applied to both sides in a circumferential shape so as to divide the major axis direction into 4 mm and 5 mm portions, and then masked. 100 temporary bars were set on one support frame (hereinafter referred to as a handling frame), and 25 sets (No. 1 to No. 25) of handling frames containing temporary bars were similarly prepared.

(b) Film formation on the conductor surface 1-No. 25 is sequentially transferred onto a 5% by mass ammonium adipate aqueous solution and vertically lowered toward the solution to immerse a 3 mm × 4 mm portion of each conversion foil in the solution, and a voltage of 4 V is applied as it is. This was applied to form a cut portion, and a dielectric oxide film was formed.

(c) Immersion and pulling in monomer solution Next, these handling frame Nos. 1-No. 25 is sequentially transferred onto a 2.0 mol / L isopropyl alcohol (IPA) solution (monomer solution) in which 3,4-ethylenedioxythiophene is dissolved, and vertically dropped toward the solution, A 3 mm × 4 mm portion of the conversion foil was immersed in the solution for 3 seconds. Subsequently, 25 handling frames were successively treated and dried at room temperature for 2 minutes.

(d) Immersion in oxidant solution and subsequent treatment On the other hand, a 20% by mass ammonium persulfate aqueous solution (oxidant solution) was prepared, and a predetermined amount was put in the oxidant tank. 1 (lead HF) was moved onto this solution, and a 3 mm × 4 mm portion of each chemical conversion foil was immersed in the solution for 5 seconds. Then, it hold | maintained in the polymerization promotion tank for 10 minutes, and formed the polymer film. No. 2-No. Up to 24 handling frames were processed. Thereafter, the entire amount of the oxidant solution was extracted from the oxidant tank, and after the new liquid was replenished, the final handling frame (No. 25) was immersed and charged into the polymerization promotion tank.

(e) Repeated operation Next, the first handling frame after the completion of the polymerization promotion treatment was immersed in the monomer solution, dried at room temperature for 2 minutes, and then immersed in the oxidant solution. In this second immersion, no. After the handling frame processing of No. 23, the entire amount of the oxidant solution was changed. 24, no. 25 handling frames were processed. After immersion in the oxidant solution, both were put into the polymerization accelerating tank again. Similarly, after replacing the oxidant solution, the oxidant solution was replaced with a new solution every time 24 handling frames were processed. The polymerization was completed up to the 20th round. The finally produced poly (3,4-ethylenedioxythiophene) was washed in warm water at 50 ° C. and then dried at 110 ° C. for 10 minutes to form a solid electrolyte layer.

  Twenty temporary bars were sampled from each handling frame after the above polymerization, the average thickness of 600 elements was calculated, and data for 25 handling frames were collected. The results of the element thickness are shown in Table 1, and the order of the handling frames and the transition of the average element thickness are shown together in FIG.

(f) Manufacture of Capacitor Next, a 3 mm × 4 mm portion where the solid electrolyte layer was formed was immersed in a 5 mass% ammonium adipate solution for re-chemical conversion.
Further, a carbon paste and a silver paste were adhered to the portion of the aluminum foil where the conductive polymer composition layer 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. 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 to complete a capacitor.

Example 2
In the same manner as in Example 1, except that the replacement amount of the oxidant solution of Example 1 was 15% of the total (15% of the used oxidant solution was discarded and a new solution was replenished). An electrolyte layer was formed. The results measured in the same manner as in Example 1 are summarized in Table 1 and FIG.

Comparative Example 1
Every time 25 handling frames were processed, the entire amount of the oxidant solution was changed in the same manner as in Example 1 to form a solid electrolyte layer. The results measured in the same manner are shown in Table 1 and FIG.

Comparative Example 2
Each time 25 handling frames were processed, 15% of the oxidant solution was replaced with a new solution in the same manner as in Example 2 to form a solid electrolyte layer. The results measured in the same manner are shown in Table 1 and FIG.

  As shown in the above table and FIG. 5, in the examples in which the handling frames were substantially shifted one by one and the oxidant immersion treatment was performed, the film thickness of the solid electrolyte layer was respectively compared with the comparative example immersed without shifting. Averaged as a whole. In the comparative example, the element thickness tends to increase from the first HF to the final HF as a whole, but in the present invention, an increase in thickness due to substantially changing the order of the handling frames can be prevented. In addition, the problem that an element having an abnormally thick layer is eliminated is solved, and the overall yield is improved. Furthermore, in these embodiments, since the handling frame transport order does not have to be changed, no major changes are required in equipment and device control.

Example 3
A solid electrolyte layer was formed in the same manner as in Example 1 except that the processing order of the handling frames was changed randomly in each cycle, and the entire amount of the oxidant solution was changed every time 25 handling frames were processed. The processing order of each cycle was determined by random numbers generated appropriately by a computer. The element was sampled in the same manner as in Example 1 and the element thickness was measured. The same experiment was repeated three times. The variation (σ) in the average element thickness between the handling frames was 2.21, and the average element thickness was 210.5 μm.

Example 4
A solid electrolyte layer was formed in the same manner as in Example 2 except that the processing order of the handling frames was changed randomly in each cycle, and the oxidant solution was changed every time 25 handling frames were processed. The processing order of each cycle was determined by random numbers generated appropriately by a computer. The element was sampled in the same manner as in Example 2 and the element thickness was measured. The same experiment was repeated three times. The variation (σ) in the average element thickness between the handling frames was 2.83, and the average element thickness was 216.2 μm.

  Further, for each of the above examples and comparative examples, a completed capacitor (stacked with four elements) is arbitrarily extracted, and the initial characteristics are 120 Hz capacity and loss factor (tan δ × 100 (%)), equivalent series resistance (ESR) And the leakage current was measured. The leakage current was measured 1 minute after applying the rated voltage. As a result, in all cases, the product of the present invention (Example product) was superior to the Comparative product.

  According to the method of the present invention, it is possible to control the thickness of the solid electrolyte layer, in particular, to average the layer thickness, so that a solid electrolytic capacitor with uniform electrical characteristics can be obtained. In particular, there is provided a method for manufacturing a multilayer solid electrolytic capacitor that is less likely to cause problems such as device misalignment during stacking and that is less likely to cause unsealed products during sealing. Note that the method of the present invention is also useful in general composite materials using oxidative polymerization.

Sectional drawing which shows the typical structure of the capacitor | condenser element for solid electrolytic capacitors. Sectional drawing which shows the typical structure of the solid electrolytic capacitor obtained by laminating | stacking a capacitor | condenser element. Explanatory drawing which shows typically the oxidizing agent immersion process of the base material by a conventional method. Explanatory drawing which shows typically the oxidizing agent immersion process of the base material by 1 aspect of this invention. Handling frame (HF) No. in Examples and Comparative Examples. 1-N. The graph which shows the change of 25 element thickness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anode base | substrate 2 Oxide film layer 3 Solid electrolyte layer 4 Conductor layer 5 Masking layer 6 Capacitor element 7 Anode 8 Cathode 9 Sealant 11 Base material 12 Oxidizing agent

Claims (13)

  In a method for manufacturing a composite material in which a polymer layer is formed on a substrate surface by repeatedly attaching a monomer-containing solution to a plurality of substrates and then sequentially immersing the substrate in an oxidizing agent-containing solution, the monomer-containing solution is attached. A method for producing a composite material, characterized in that the immersion is repeated by changing the immersion order of the base material.   The method for producing a composite material according to claim 1, wherein the order of dipping the base material is changed every time the step is repeated.   The method for producing a composite material according to claim 1 or 2, wherein the immersion order is changed by randomly rearranging the immersion order.   The method for producing a composite material according to claim 1 or 2, wherein the immersion order is changed by shifting the immersion order.   The method for producing a composite material according to any one of claims 1 to 4, wherein a part or all of the oxidizing agent-containing liquid is exchanged with a new liquid during any one of the repeating steps.   The method for producing a composite material according to any one of claims 1 to 4, wherein a part or all of the oxidant-containing liquid is replaced with a new liquid after completion of any one of the repetitive steps and before the next repetitive step.   The manufacturing method of the composite material in any one of Claims 1-6 which hold | maintain the some base material to which the monomer containing liquid was made to adhere to several support members, and perform the said immersion operation for every support member.   The method for producing a composite material according to claim 1, wherein the base material is a valve metal having a porous layer on the surface, and the monomer is a monomer of a conductive polymer.   The method for manufacturing a solid electrolytic capacitor element according to claim 8, wherein the composite material to be manufactured is a solid electrolytic capacitor element.   A solid electrolytic capacitor element produced by the method according to claim 9.   A solid electrolytic capacitor using the solid electrolytic capacitor element according to claim 10.   A multilayer solid electrolytic capacitor comprising a plurality of capacitor elements according to claim 10 stacked.   A solid electrolytic capacitor manufacturing apparatus that employs the manufacturing method according to claim 9.

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