Method and apparatus for producing plating composition

Abstract

Provided is an efficient method for producing a plating composition. This method for producing a plating composition is performed by using an electrochemical device provided with a working electrode chamber including a first working electrode and a first plating composition, and a counter electrode chamber that is separated from the working electrode chamber by a separating membrane and that includes a counter electrode and a counter electrode liquid, the method comprising: reducing, to a metal, at least a portion of first metal ions contained in the first plating composition by using the first working electrode as a cathode; and oxidizing a metal, which is of the same type as the reduced metal, into second metal ions having a lower oxidation number as compared to the first metal ions by using the first working electrode as an anode to obtain a second plating composition containing the second metal ions. In the method for producing a plating composition, the electrochemical device is provided with a plurality of such working electrode chambers and / or a plurality of such counter electrode chambers, and at least portions of the counter electrodes and the first working electrodes are alternately disposed so as to face each other with a separating membrane therebetween.

Description

Plating composition manufacturing method and manufacturing apparatus

[0001] The present invention relates to a method and an apparatus for producing a plating composition.

[0002] In relation to plating compositions used in metal plating, JP 2015-518923 A proposes a method for regenerating a plating composition by oxidizing and reducing two types of metal components in the plating composition using an apparatus equipped with a working electrode chamber, a counter electrode chamber, and an ion exchange membrane separating them.

[0003] When a plating composition is regenerated using a working electrode and a counter electrode separated by a diaphragm such as an ion exchange membrane, only the opposing surfaces of the electrodes substantially contribute to the redox reaction. This tends to narrow the effective electrode area per treatment solution, lengthen the treatment time, or increase the equipment area. One aspect of the present invention aims to provide a method for producing a plating composition by regenerating a used or denatured plating composition, which method allows for efficient redox reaction.

[0004] A first aspect is a method for producing a plating composition, the method comprising: using an electrochemical apparatus including a working electrode chamber containing a first working electrode and a first plating composition, and a counter electrode chamber separated from the working electrode chamber by a diaphragm and containing a counter electrode and a counter electrode solution; reducing at least a portion of first metal ions contained in the first plating composition to a metal using the first working electrode as a cathode; and oxidizing a metal of the same type as the reduced metal to a second metal ion having a lower oxidation number than the first metal ion using the first working electrode as an anode, thereby obtaining a second plating composition containing the second metal ion. The electrochemical apparatus includes a plurality of at least one of the working electrode chambers and the counter electrode chambers. Furthermore, at least a portion of the counter electrodes and the first working electrodes are arranged alternately opposite each other with the diaphragm interposed therebetween.

[0005] A second aspect is an apparatus for producing a plating composition, which includes a working electrode chamber having a first working electrode and a counter electrode chamber separated from the working electrode chamber by a diaphragm and having a counter electrode. The apparatus for producing a plating composition includes a plurality of working electrode chambers and / or a plurality of counter electrode chambers. At least some of the first working electrodes and / or counter electrodes are arranged to face each other alternately with the diaphragm interposed therebetween.

[0006] According to one aspect of the present invention, an efficient method for producing a plating composition can be provided.

[0007] FIG. 1 is a flowchart showing an example of the order of steps in a method for producing a plating composition; FIG. 2 is a schematic diagram illustrating an example of steps in a method for producing an electronic component; FIG. 3 is a schematic perspective view showing an example of the configuration of an electrochemical device according to the present embodiment; FIG. 4 is a schematic perspective view showing an example of the configuration of a first working electrode; FIG. 5 is a schematic perspective view showing an example of the configuration of a counter electrode chamber; FIG. 6 is a schematic cross-sectional view showing an example of the configuration of an electrochemical device according to Example 1; FIG. 7 is a schematic cross-sectional view showing an example of the configuration of an electrochemical device according to Example 2; FIG. 8 is a schematic cross-sectional view showing an example of the configuration of an electrochemical device according to Example 3; FIG. 9 is a schematic cross-sectional view showing an example of the configuration of an electrochemical device according to Example 4; FIG. 10 is a schematic cross-sectional view showing an example of the configuration of an electrochemical device according to Example 5; and FIG. 11 is a schematic top view showing an example of the configuration of an electrochemical device according to Example 6.

[0008] As used herein, the term "process" refers not only to an independent process, but also to processes that are indistinguishable from other processes, as long as the intended purpose of the process is achieved. Furthermore, unless otherwise specified, the content of each component in a composition refers to the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition. Furthermore, the upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges. Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below exemplify the plating composition manufacturing method and manufacturing apparatus for embodying the technical concept of the present invention, and the present invention is not limited to the plating composition manufacturing method and manufacturing apparatus described below. The components described in the claims are in no way limited to the components of the embodiments. Unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiments are merely illustrative examples and are not intended to limit the scope of the present invention. The same symbols are used in each figure. For convenience, the embodiments are shown separately to facilitate explanation and understanding of the main points, but partial substitution or combination of the configurations shown in different embodiments is possible. From Example 2 onwards, descriptions of matters common to Example 1 will be omitted, and only the differences will be described. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment.

[0009] 1. Method for Producing a Plating Composition The method for producing a plating composition includes a first metal ion reduction step using an electrochemical device including a working electrode chamber containing a first working electrode and a first plating composition, and a counter electrode chamber separated from the working electrode chamber by a diaphragm and containing a counter electrode and a counter electrode solution, in which at least a portion of the first metal ions contained in the first plating composition are reduced to a metal using the first working electrode as a cathode, and a second metal ion oxidation step using the first working electrode as an anode to oxidize a metal of the same type as the reduced metal to a second metal ion having a lower oxidation number than the first metal ion, thereby obtaining a second plating composition containing the second metal ions. The electrochemical device may include a plurality of working electrode chambers and / or counter electrode chambers. Furthermore, at least a portion of the counter electrodes and the first working electrodes may be arranged alternately facing each other via diaphragms.

[0010] In an electrochemical device having a plurality of working electrode chambers and / or counter electrode chambers, the first metal ions contained in the first plating composition are reduced in the working electrode chamber, thereby enabling the use of both surfaces of at least one of the counter electrode and the first working electrode. This increases the effective electrode area that substantially contributes to the oxidation-reduction reaction, allowing the reduction reaction of the first metal ions to be carried out efficiently. The method for producing a plating composition may also be a plating composition regeneration method for regenerating a plating composition usable for plating processing (e.g., a second plating composition) from a used plating composition or plating wastewater (e.g., a first plating composition).

[0011] In one embodiment, a method for producing a plating composition includes introducing a first plating composition containing first metal ions into a working electrode chamber equipped with a counter electrode chamber containing a counter electrode and a counter electrode solution, and a first working electrode; reducing at least a portion of the first metal ions contained in the introduced first plating composition to a metal using the first working electrode as a cathode; and oxidizing a metal identical to the reduced metal to a second metal ion having a lower oxidation number than the first metal ion using the first working electrode as an anode, thereby obtaining a second plating composition containing the second metal ions. In the method for producing a plating composition, the working electrode chamber may include a plurality of at least one of a counter electrode chamber and a first working electrode. Furthermore, at least a portion of the counter electrodes and the first working electrodes may be arranged alternately facing each other via a diaphragm provided in the counter electrode chamber.

[0012] In a working electrode chamber having a plurality of counter electrode chambers and / or a plurality of first working electrodes, the first metal ions contained in the first plating composition are reduced, thereby enabling the use of both surfaces of at least one of the counter electrode and the first working electrode, thereby increasing the effective electrode area that substantially contributes to the redox reaction and enabling the reduction reaction of the first metal ions to be carried out efficiently.

[0013] In another embodiment, a method for producing a plating composition includes: introducing a first plating composition containing first metal ions into a working electrode chamber including a first working electrode, a counter electrode, and a counter electrode solution; reducing at least a portion of the first metal ions contained in the introduced first plating composition to a metal using the first working electrode as a cathode; and oxidizing a metal identical to the reduced metal to a second metal ion having a lower oxidation state than the first metal ion using the first working electrode as an anode, thereby obtaining a second plating composition containing the second metal ions. In the method for producing a plating composition, the counter electrode chamber may include a plurality of at least one of counter electrodes and working electrode chambers. Furthermore, at least a portion of the counter electrodes and the first working electrodes may be arranged alternately opposite each other via a diaphragm provided in the working electrode chamber.

[0014] The counter electrode chamber includes a plurality of working electrode chambers and / or a plurality of counter electrodes, and the first metal ions contained in the first plating composition are reduced in the working electrode chamber. This allows the use of both surfaces of the counter electrode and / or the first working electrode, thereby increasing the effective electrode area that substantially contributes to the redox reaction and enabling the reduction reaction of the first metal ions to be carried out efficiently.

[0015] One embodiment of a method for producing a plating composition will be described with reference to the drawings. FIG. 1 is a flowchart showing an example of the process sequence of the method for producing a plating composition. The method for producing a plating composition may include an impurity removal step S201, a first metal ion reduction step S202, and a second metal ion oxidation step S203, which are included as necessary. In the impurity removal step S201, at least a portion of impurities are removed from the first plating composition, which is a plating wastewater recovered from a plating tank or a water rinsing tank. In the first metal ion reduction step S202, a first metal ion with a high oxidation state (e.g., tin(IV) ion) contained in the plating composition is reduced to a metal (e.g., metallic tin) using an electrochemical device.

[0016] The electrochemical device includes a counter electrode chamber containing a counter electrode and a counter electrode solution, and a working electrode chamber including a first working electrode. The electrochemical device includes a plurality of counter electrode chambers and / or working electrode chambers, and the counter electrode chambers and / or working electrode chambers are at least partially separated by a diaphragm. In one aspect, the electrochemical device may include a counter electrode chamber and a first working electrode disposed in the working electrode chamber, and may include a plurality of counter electrode chambers and / or first working electrodes, and at least a portion of the wall surface defining the counter electrode chamber may be formed by a diaphragm. In another aspect, the electrochemical device may include a counter electrode and a working electrode chamber disposed in the counter electrode chamber, and may include a plurality of counter electrodes and / or working electrode chambers, and at least a portion of the wall surface defining the working electrode chamber may be formed by a diaphragm.

[0017] At least a portion of the counter electrode and the first working electrode are arranged alternately opposite each other via a diaphragm provided between the counter electrode chamber and the working electrode chamber. In the electrochemical device, it is sufficient that at least a portion of the counter electrodes and the first working electrodes present are arranged alternately. A portion of the counter electrodes may be arranged continuously opposite each other, or a portion of the first working electrode may be arranged continuously opposite each other. Here, "arranged electrodes facing each other" means that at least a portion of the surface of one electrode is arranged opposite to at least a portion of the surface of the other electrode. The two opposing surfaces may both be main surfaces, or one may be a main surface and the other a side surface. The shapes of the two opposing surfaces may be flat, curved, or uneven. The two opposing surfaces may be parallel or inclined (non-parallel) to each other. In one aspect, the opposing electrodes may have their main surfaces arranged approximately parallel to each other.

[0018] The reduction of the first metal ions is carried out by introducing a first plating composition into the working electrode chamber and performing electrolysis using the first working electrode as the cathode, resulting in the deposition of a metal on the first working electrode. The second metal ion oxidation step S203 is carried out by performing electrolysis using the first working electrode as the anode, resulting in the metal deposited on the first working electrode or a metal of the same kind being oxidized to a second metal ion of a lower oxidation number (e.g., tin(II) ion) and dissolving in the plating composition in the working electrode chamber, resulting in the production of a second plating composition usable for plating.

[0019] In FIG. 1 , the first metal ion reduction step S202 and the second metal ion oxidation step S203 are performed after the impurity removal step S201. By performing the impurity removal step before the first metal ion reduction step, the first metal ions can be reduced more efficiently. In one embodiment, the method for producing a plating composition may perform the first metal ion reduction step S202 and the second metal ion oxidation step S203 without performing the impurity removal step. Also, the impurity removal step S101 may not be performed.

[0020] First Metal Ion Reduction Step In the first metal ion reduction step, a first plating composition containing first metal ions is introduced into a working electrode chamber equipped with a first working electrode, and at least a portion of the first metal ions contained in the introduced first plating composition are reduced to metal using the first working electrode as the cathode. The first plating composition may be, for example, a plating effluent used in metal plating, or a plating effluent obtained by rinsing a metal-plated article with water. The working electrode chamber may also include a counter electrode chamber containing a counter electrode and a counter electrode solution, or the counter electrode and counter electrode solution may be disposed in the counter electrode chamber separated from the working electrode chamber by a diaphragm.

[0021] The first metal ion contained in the first plating composition may be a metal ion in a more highly oxidized state than the second metal ion, or may be produced by oxidation of the second metal ion constituting the plating composition prior to use. Examples of the first metal ion include tin(IV) ions, Cu(II) ions, and Fe(III) ions.

[0022] The content of the first metal ion in the first plating composition may be, for example, 0.1 g / L or more and 100 g / L or less, and preferably 1 g / L or more. The first plating composition may also contain a complexing agent, and the content thereof may be, for example, equimolar to 20 times the molar amount of the first metal ion, and preferably 10 times or less. The content of the first metal ion in the first plating composition is measured, for example, by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or by oxidation-reduction titration with potassium iodate after reduction with iron powder.

[0023] In one embodiment, the working electrode chamber may include a plurality of counter electrode chambers and / or a plurality of first working electrodes, and at least a portion of the counter electrodes and the first working electrodes may be arranged to alternately face each other via a diaphragm provided in the counter electrode chamber. An example of a working electrode chamber will now be described with reference to the drawings. Figure 3A is a schematic perspective view showing an example of an electrochemical device 50 including a working electrode chamber 52. In addition to the working electrode chamber, the electrochemical device 50 may further include a power supply unit, a control unit, a temperature control unit, and the like that enable electrolysis.

[0024] The working electrode chamber 52 may have any shape capable of holding the first plating composition therein, such as a box-like shape having side and bottom surfaces. The top surface of the working electrode chamber 52 may be open or closed. In FIG. 3A , the working electrode chamber 52 has a plurality of first working electrodes 54 and a plurality of counter electrode chambers 56 therein. As shown in FIG. 3B , the first working electrodes 54 may be flat electrodes having two main surfaces and side surfaces connecting the outer edges of the two main surfaces. As shown in FIG. 3C , the counter electrode chamber 56 has a flat counter electrode 56 b and a counter electrode solution 56 c disposed therein. The counter electrode chamber 56 may have any shape capable of holding the counter electrode solution 56 c therein, such as a box-like shape having two main surfaces and side surfaces and a bottom surface connecting the two main surfaces. The top surface of the counter electrode chamber 56 may be open or closed. The counter electrode chamber 56 may be rectangular in top view, with long sides corresponding to the main surface and short sides corresponding to the side surfaces. At least a portion of the main surface of the counter electrode chamber 56 is formed by a diaphragm 56a. The diaphragm 56a may be selected from an ion exchange membrane, a reverse osmosis membrane (RO membrane), a nanofiltration membrane (NF membrane, loose RO membrane), etc. The counter electrode 56b may be a flat electrode having two main surfaces and a side surface connecting the outer edges of the two main surfaces. The first working electrodes 54 and the counter electrodes 56b are arranged alternately opposite each other with the diaphragm 56a interposed therebetween. The first working electrodes 54 and the counter electrodes 56b are arranged with their main surfaces facing each other.

[0025] 3A , one more first working electrode 54 is disposed than the counter electrode chamber 56. This allows both surfaces of the counter electrode 56b to be used effectively. Also, in the working electrode chamber 52, at least one more counter electrode chamber 56 may be disposed than the first working electrode 54. This allows both surfaces of the first working electrode 54 to be used effectively.

[0026] 3A shows an electrochemical device in which a counter electrode chamber and a first working electrode are disposed in the working electrode chamber, but in another embodiment, the working electrode chamber and the counter electrode chamber may be interchanged. That is, the working electrode chamber and the counter electrode may be disposed in the counter electrode chamber. Note that the working electrode chamber and the counter electrode chamber may also be interchanged in the electrochemical devices shown in other drawings.

[0027] The working electrode chamber 52 may have a second working electrode 55 on its bottom surface. The second working electrode 55 may be disposed, for example, extending to the bottom surface of the working electrode chamber. By having the second working electrode 55 in the working electrode chamber 52, for example, metal sludge that may be generated in the second metal ion oxidation step described below can be efficiently oxidized, thereby improving the recovery rate of metal ions.

[0028] Examples of materials for the first working electrode and the second working electrode include gold, platinum, platinum-coated titanium, silver, nickel, graphite, tin, titanium, iridium oxide, and ruthenium oxide. Examples of materials for the counter electrode include platinum, platinum-coated titanium, gold, nickel, iridium oxide, ruthenium oxide, titanium, graphite, and palladium. The materials for the first working electrode, the second working electrode, and the counter electrode may be the same or different. The shapes of the first working electrode, the second working electrode, and the counter electrode include plate-like and mesh-like shapes, and may be flat or have curved or uneven portions. The thicknesses of the first working electrode, the second working electrode, and the counter electrode are not particularly limited and may be selected appropriately depending on the size of the working electrode chamber, etc. The thicknesses of the first working electrode, the second working electrode, and the counter electrode may be, for example, 0.01 mm or more and 5 mm or less. The surface roughness of the first working electrode, the second working electrode, and the counter electrode is not particularly limited and may be, for example, 30 nm or more in terms of arithmetic mean height Sa.

[0029] At least a portion of the first working electrode and the counter electrode may be arranged with their respective main surfaces facing each other, with a diaphragm interposed therebetween. The diaphragm may form the main surface of the counter electrode chamber. The diaphragm may be any membrane that is impermeable to the first metal ion. The diaphragm may be at least one selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane (RO membrane), a nanofiltration membrane (NF membrane, loose RO membrane), etc. By making the diaphragm impermeable to the first metal ion, the first metal ion can be reduced more efficiently. The ion exchange membrane may be a cation exchange membrane, an anion exchange membrane, or a combination of both. The ion exchange membrane may be appropriately selected from commercially available ion exchange membranes. The ion exchange membrane may include at least a cation exchange membrane from the viewpoint of the reduction efficiency of the first metal ion. For example, the cation exchange membrane may include a fluororesin copolymer based on sulfonated tetrafluoroethylene.

[0030] The distance between the principal surfaces of the first working electrode and the counter electrode may be appropriately selected depending on the size of the working electrode chamber, etc. The distance between the principal surfaces of the first working electrode and the counter electrode may be, for example, 1 mm or more and 200 mm or less. Here, the distance between the principal surfaces refers to the distance between the surface of the first working electrode facing the counter electrode and the surface of the counter electrode facing the first working electrode. The distance between the principal surface of the counter electrode and the surface of the diaphragm may be, for example, 0.5 mm or more and 100 mm or less, and the distance between the principal surface of the first working electrode and the surface of the diaphragm may be, for example, 0.5 mm or more and 100 mm or less. Here, the distance between the principal surface of the counter electrode and the surface of the diaphragm refers to the distance between the surface of the counter electrode facing the diaphragm and the surface of the diaphragm facing the counter electrode, and the distance between the principal surface of the first working electrode and the surface of the diaphragm refers to the distance between the surface of the first working electrode facing the diaphragm and the surface of the diaphragm facing the first working electrode. The ratio of the distance between the principal surface of the counter electrode and the surface of the diaphragm to the distance between the principal surface of the first working electrode and the surface of the diaphragm may be, for example, 0.005 or more and 200 or less.

[0031] A counter electrode solution is disposed inside the counter electrode chamber. The counter electrode solution may be an aqueous solution containing conductive ions. The aqueous solution containing conductive ions may contain at least water and conductive ions. The conductive ions may be derived from a water-soluble metal salt or a water-soluble acidic compound. Examples of conductive ions include cations such as hydrogen ions, alkali metal ions, and alkaline earth metal ions; and anions such as sulfate ions, nitrate ions, phosphate ions, halogen ions, alkanesulfonate ions, alkanolsulfonate ions, aromatic sulfonate ions, alkylcarboxylate ions, and arylcarboxylate ions.

[0032] In the first metal ion reduction step, at least a portion of the first metal ions in the first plating composition introduced into the working electrode chamber are reduced to elemental metals by a first electrolysis treatment using the first working electrode as a cathode. The elemental metals produced by the reduction may be deposited on the first working electrode, for example. The current density in the electrolysis treatment of the first metal ions may be selected appropriately depending on the type of first metal ions. The current density may be, for example, 0.05 A / dm ２ More than 5A / dm ２ may be less than or equal to 0.1 A / dm ２ or more, or 2A / dm ２ The temperature in the electrolysis treatment may be, for example, 20° C. or higher and 80° C. or lower, and preferably 35° C. or higher or 75° C. or lower. The time required for the electrolysis treatment may be, for example, 10 minutes or longer and 200 hours or shorter.

[0033] The first metal ion contained in the first plating composition may be a simple metal ion or a complex ion. Examples of complexing agents that form complex ions include carboxylic acids, such as gluconic acid (including gluconolactone), citric acid, glutaric acid, succinic acid, malic acid, tartaric acid, lactic acid, acetic acid, malonic acid, and salts or derivatives thereof; phosphoric acids, such as tripolyphosphoric acid and hydroxyethanediphosphonic acid, and salts thereof; sugars, such as sorbitol, mannitol, and salts thereof; amino acids, such as phenylalanine, glutamic acid, aspartic acid, alanine, glycine, and salts thereof; HEDTA, EDTA, and the like. The complexing agent may contain at least one selected from the group consisting of these, and may contain at least gluconic acid. The complexing agents may be used alone or in combination of two or more. When the first metal ion is a complex ion, the pH of the plating composition used for plating can be set to a weakly acidic to weakly alkaline range, thereby suppressing corrosion of the object to be plated that is vulnerable to strong acids or strong alkalis (e.g., an object that uses an oxide as a component, such as a ceramic capacitor).

[0034] The first plating composition may contain, in addition to the first metal ion, a second metal ion having a lower oxidation number than the first metal ion. A specific example of the second metal ion is a tin(II) ion when the first metal ion is a tin(IV) ion. A specific example of the second metal ion is an Fe(II) ion when the first metal ion is an Fe(III) ion. The second metal ion may be a simple metal ion or a complex ion. The complexing agent that forms the complex ion is the same as that for the first metal ion. When the first plating composition contains the second metal ion, the content of the second metal ion contained in the first plating composition may be, for example, 100 g / L or less, preferably 20 g / L or less. The content of the second metal ion contained in the first plating composition is measured in the same manner as for the first metal ion.

[0035] The second metal ions may be derived from the plating composition prior to use. The second metal ions constituting the plating composition prior to use may be derived from a water-soluble metal salt. Specific examples of water-soluble metal salts include sulfates, chlorides, boron fluorides, alkanesulfonates, alkanolsulfonates, and aromatic sulfonates. The plating composition may contain at least one selected from the group consisting of these, and may contain at least an alkane sulfonate. Examples of the alkane sulfonic acid in the alkane sulfonate include alkanesulfonic acids having 1 to 3 carbon atoms, and specific examples include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and 2-propanesulfonic acid.

[0036] The first plating composition may further contain alkali metal ions, ammonium ions, etc., derived from the plating composition prior to use. The inclusion of alkali metal ions, ammonium ions, etc. increases the electrical conductivity, suppresses heat generation due to solution resistance during electroplating, and tends to improve electrodeposition uniformity. Examples of alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium, and cesium. The alkali metal ions, ammonium ions, etc. may be added to the plating composition prior to use as, for example, a salt with an acid component. The inclusion of an acid component in the plating composition prior to use, for example, further improves the stability of the plating composition. Examples of acid components include sulfuric acid, hydrochloric acid, alkanesulfonic acid, alkanolsulfonic acid, aromatic sulfonic acid, phosphoric acid, alkylcarboxylic acid, and arylcarboxylic acid. The first plating composition may contain at least one selected from the group consisting of these acids. These acids may be used alone or in combination.

[0037] The pH of the first plating composition may be, for example, 0 or more and 14 or less, preferably 0.5 or more, 3 or more, or 4 or more, and preferably 11 or less, 9 or less, or 7 or less. When the pH of the first plating composition is within the above range, the first metal ions tend to be reduced more efficiently. The pH of the first plating composition may be adjusted to a desired range, for example, with a pH adjuster. Examples of pH adjusters include alkali metal hydroxides, ammonia, and the like, in addition to the acid components described above.

[0038] The first plating composition may further contain an antioxidant derived from the plating composition prior to use. The inclusion of an antioxidant can, for example, improve the stability of the plating composition prior to use and extend the bath life. Examples of antioxidants include hydroquinone, ascorbic acid, catechol, hypophosphorous acid, and erythorbic acid. When the first plating composition contains an antioxidant, the content of the antioxidant in the first plating composition may be, for example, 0.01 g / L or more and 20 g / L or less, and preferably 0.1 g / L or more or 5 g / L or less.

[0039] If the first plating composition includes an antioxidant, the first metal ion reduction step may include removing at least a portion of the antioxidant, which may be accomplished by activated carbon treatment.

[0040] The first plating composition contains water as a solvent. The total concentration of solutes in the first plating composition may be, for example, 750 g / L or less, preferably 400 g / L or less, or 300 g / L or less. The total concentration of solutes in the first plating composition may be, for example, 50 g / L or more.

[0041] The first plating composition may be, for example, a plating wastewater used in metal plating, or a plating wastewater obtained by rinsing a metal-plated article with water. The first plating composition may contain impurities. The impurities refer to substances that may inhibit the reduction of the first metal ions in the first metal ion reduction step described below. Specific examples of impurities include additives such as surfactants, leveling agents, brighteners, and antioxidants, metal components different from the first metal, dust, precipitates, etc.

[0042] The first plating composition may contain, as at least a portion of the impurities, a surfactant derived from the plating composition prior to use. The surfactant may be any of a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, etc. Furthermore, the surfactant may function as a so-called brightener, leveler, etc. in the plating composition. From the viewpoint of the reduction efficiency of the first metal ion, the surfactant may include at least one selected from the group consisting of a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. The first plating composition may contain only one surfactant or a combination of two or more surfactants.

[0043] Examples of nonionic surfactants include ester surfactants in which a polyhydric alcohol such as glycerin, sorbitol, or sucrose is ester-bonded to a fatty acid; ether surfactants formed by adding ethylene oxide, propylene oxide, or the like to a compound having a hydroxyl group such as a higher alcohol or an alkylphenol; and ester-ether surfactants formed by adding ethylene oxide, propylene oxide, or the like to an ester surfactant. Specific examples of nonionic surfactants include polyethylene glycol, polypropylene glycol, polyoxyethylene octylphenol, polyoxyethylene β-naphthyl ether, polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid ester and its ethylene oxide adduct, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid monoethanolamide and its ethylene oxide adduct, fatty acid N-methyl monoethanolamide and its ethylene oxide adduct, fatty acid diethanolamide and its ethylene oxide adduct, sucrose fatty acid ester, alkyl (poly)glycerin ether, polyglycerin fatty acid ester, polyethylene glycol fatty acid ester, fatty acid methyl ester ethoxylate, N-long-chain alkyldimethylamine oxide, etc. Nonionic surfactants may have fluorine atoms substituted in their structures.

[0044] Examples of cationic surfactants include amine salts and quaternary ammonium salts.Specific examples of cationic surfactants include alkyl (or alkenyl) trimethyl ammonium salts, alkyl (or alkenyl) triethyl ammonium salts, dialkyl (or alkenyl) dimethyl ammonium salts, alkyl (or alkenyl) quaternary ammonium salts, mono- or dialkyl (or alkenyl) quaternary ammonium salts containing ether groups, ester groups, or amide groups, alkyl (or alkenyl) pyridinium salts, alkyl (or alkenyl) dimethyl benzyl ammonium salts, alkyl (or alkenyl) isoquinolinium salts, dialkyl (or alkenyl) morphonium salts, polyoxyethylene alkyl (or alkenyl) amines, alkyl (or alkenyl) amine salts, polyamine fatty acid derivatives, amyl alcohol fatty acid derivatives, benzalkonium chloride, benzethonium chloride, etc.These cationic surfactants may have fluorine atoms substituted in their structures.

[0045] Amphoteric surfactants exhibit the properties of anionic surfactants in the alkaline range and the properties of cationic surfactants in the acidic range. Examples of amphoteric surfactants include carboxylates and sulfonates, and may be either amino acid-type or betaine-type. Specific examples of amphoteric surfactants include alkyldimethylaminoacetic acid betaine, alkyldimethylacetic acid betaine, alkyldimethylcarboxybetaine, alkyldimethylcarboxymethyleneammonium betaine, alkyldimethylammonioacetate, fatty acid amidopropyldimethylamino acid betaine, alkyloylamidopropyldimethylglycine, 2-alkyl-1-(2-hydroxyethyl)imidazolium-1-acetate, alkyldiaminoethylglycine, dialkyldiaminoethylglycine, and alkyldimethylamine oxide.

[0046] Examples of the anionic surfactant include carboxylates, sulfonates, sulfates, and phosphates.

[0047] The surfactant content in the first plating composition may be, for example, 0.01 g / L or more and 10 g / L or less, and preferably 0.1 g / L or more or 5 g / L or less. The surfactant content can be measured using surface tension as an index. Specifically, it can be measured using a drop counter.

[0048] When the first plating composition contains a surfactant, a surfactant removal step of removing at least a portion of the surfactant from the first plating composition may be performed as at least part of the impurity removal step prior to the first metal ion reduction step. This allows the reduction of the first metal ions to be performed more efficiently. The surfactant content in the first plating composition after removal in the surfactant removal step may be, for example, 0.01 g / L or less.

[0049] Examples of methods for removing the surfactant in the surfactant removal step include activated carbon treatment and gel filtration treatment. The surfactant removal method may preferably include activated carbon treatment. The surfactant removal method using activated carbon treatment may include, for example, contacting the first plating composition with activated carbon. By using activated carbon, at least a portion of the surfactant can be more efficiently removed from the first plating composition. In the surfactant removal step, a method of electrostatically adsorbing the surfactant (e.g., contacting the surfactant with an ion exchange resin) may be combined with activated carbon treatment.

[0050] Activated carbon is a porous material whose main component is carbon and that has been subjected to a chemical or physical activation process. The activated carbon used in the activated carbon process may be activated with chemicals or gases. The activated carbon may be powdered activated carbon, granular activated carbon, or a combination of these.

[0051] The specific surface area of ​​activated carbon is, for example, 200 m ２ / g or more 1500m ２ / g or less, and preferably 300m ２ / g or more, or 700m ２ / g or less. The specific surface area is measured based on the BET (Brunauer Emmett Teller) theory using nitrogen gas after heat treatment at 200°C for 6 hours as a pretreatment. The average pore diameter of the activated carbon may be, for example, 1.5 nm or more and 3.5 nm or less, and preferably 2.0 nm or more and 3.0 nm or less. The mesopore shape of the activated carbon may be, for example, an average pore width on the adsorption side measured by the INNES method of 2 nm or more and 30 nm or less, and preferably 4 nm or more and 10 nm or less. The average pore width on the desorption side measured by the INNES method may be, for example, 2 nm or more and 5 nm or less, and preferably 2 nm or more and 3.5 nm or less.

[0052] The amount of activated carbon used in contact with the first plating composition may be selected appropriately depending on the type of activated carbon. The amount of activated carbon used may be an amount sufficient to remove at least a portion of the surfactant contained in the first plating composition, preferably an amount sufficient to remove 50% by mass or more, 70% by mass or more, or 90% by mass or more of the surfactant. The amount of activated carbon used may be selected depending on the method of contact with the first plating composition. For example, when contacting in a single pass, a larger amount of activated carbon may be required than when contacting by circulating the first plating composition.

[0053] The first plating composition may be contacted with the activated carbon by, for example, mixing the first plating composition with the activated carbon followed by solid-liquid separation, or by passing the first plating composition through activated carbon held in a filter, cartridge, etc. The contact temperature between the first plating composition and the activated carbon may be, for example, 0°C or higher or 70°C or lower.

[0054] Second Metal Ion Oxidation Step In the second metal ion oxidation step, a metal identical to the metal produced by reduction in the first metal ion reduction step is oxidized to second metal ions by a second electrolysis process using the first working electrode as the anode. In the second metal ion oxidation step, the metal deposited on the first working electrode in the first metal ion reduction step or a metal identical thereto may be oxidized to second metal ions by electrolysis using the first working electrode as the anode. In one aspect, the second metal ion oxidation step may oxidize at least a portion of the metal deposited on the first working electrode to second metal ions by electrolysis using the first working electrode as the anode. That is, the second metal ion oxidation step may be performed using the same electrochemical device subsequent to the reduction of the first metal ions in the first metal ion reduction step.

[0055] The current density in the electrolysis treatment of a metal may be appropriately selected depending on the type of metal. For example, the current density is 0.5 A / dm ２ More than 100A / dm ２ The temperature in the electrolysis treatment of the metal may be, for example, 10° C. or higher and 80° C. or lower, and preferably 15° C. or higher or 75° C. or lower. The time required for the electrolysis treatment may be, for example, 0.2 hours or higher and 10 hours or lower.

[0056] When the method for producing a plating composition includes an impurity removal step and the removed impurities include a surfactant, the method for producing a plating composition may further include a step of adding a surfactant to the second plating composition obtained in the second metal ion oxidation step. Plating is performed using a plating composition to which a surfactant has been added, resulting in a plating having a better surface. The surfactant added may be the same type as the surfactant removed in the impurity removal step. Furthermore, the amount of surfactant added may be approximately the same as the amount of surfactant removed in the impurity removal step.

[0057] The method for producing a plating composition according to this embodiment may be used in combination with a plating method or a method for producing electronic components including a plating step. By using the method for producing a plating composition in combination, it is possible to suppress discharge of plating wastewater in the plating method or the method for producing electronic components.

[0058] Plating Method The plating method includes a plating composition production step and a plating step of contacting an object to be plated with a plating solution containing at least a portion of the plating composition obtained in the production step to form a plating layer on the surface of the object to be plated. The plating composition production step is the same as the above-described method for producing a plating composition. By using a plating solution containing the plating composition obtained by the above-described method for producing a plating composition, a plating layer of excellent quality equivalent to that formed when a plating solution prepared immediately before use is used can be formed on the object to be plated.

[0059] In the plating process, a plating solution is brought into contact with an object to be plated to form a plating layer on the surface of the object to be plated. The plating layer may be, for example, a tin plating layer. The plating process may be electrolytic plating or electroless plating, preferably electrolytic plating. The plating solution may be a commonly used tin plating solution, except that it contains at least a portion of the regenerated plating composition obtained in the regeneration process. The plating solution may be composed of, for example, tin (II) ions, a surfactant, a complexing agent, etc. In addition to the produced plating composition, the plating solution may further contain, as necessary, surfactants, etc., removed in the production process.

[0060] There are no particular limitations on the object to be plated to which the plating method is applied, as long as it is an article on whose surface a plating layer can be formed, such as a ceramic body having a conductive layer on its surface, a composite body containing a resin and a metal magnetic powder, a substrate, an electrode provided on a base material, etc.

[0061] The thickness of the plating layer formed in the plating step is not particularly limited and may be appropriately selected depending on the purpose, etc. The thickness of the plating layer may be, for example, 0.01 μm to 100 μm, preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 10 μm, for example, 0.3 μm to 3 μm or 1 μm to 5 μm.

[0062] In the plating step, a known plating method can be applied, such as barrel plating, centrifugal plating, rack plating, or the like.

[0063] 2. Method for Manufacturing Electronic Components The method for manufacturing electronic components includes a plating composition manufacturing step and an electrode formation step of contacting a substrate having a conductive layer on its surface with a plating solution containing at least a portion of the plating composition obtained in the manufacturing step, and forming an electrode layer including a plating layer on the surface of the conductive layer. The plating composition manufacturing step is the same as in the method for manufacturing a plating composition described above. By using a plating solution containing a recycled plating composition obtained by the method for manufacturing a plating composition described above, it is possible to form external electrodes including electrode layers of excellent quality equivalent to that obtained by using a plating solution prepared just before use, and it is possible to manufacture highly reliable electronic components.

[0064] For details of electronic components manufactured by the manufacturing method for electronic components, see, for example, JP 2021-027195 A, WO 2023 / 171394, WO 2020 / 218218 (the disclosures of these documents are incorporated herein by reference in their entirety).

[0065] In the electrode formation step, a plating solution is brought into contact with an element having a conductive layer on its surface to form an electrode layer including a plating layer. The plating method in the electrode formation step may be electrolytic plating or electroless plating, preferably electrolytic plating. The plating solution may be a commonly used plating solution except that it contains at least a portion of the plating composition obtained in the plating composition production step. The plating solution may be composed of, for example, tin (II) ions, a surfactant, a complexing agent, etc. In addition to the produced plating composition, the plating solution may further contain, as necessary, a surfactant or the like that may be removed during the production step.

[0066] The element body subjected to the electrode formation step may be a component body of an electronic component. The component body is not particularly limited, and may be, for example, a multilayer ceramic capacitor, an inductor, a resistor, an LC composite component, a thermistor, or the like. In one embodiment, the component body may be a multilayer ceramic capacitor. The component body may be constructed using a method commonly used depending on the type of component body. The material of the component body is not particularly limited, and may be a material commonly used depending on the type of component body. Examples of materials include ceramic, resin, metal, and composites thereof. In one embodiment, the material of the component body may be ceramic.

[0067] The thickness of the plating layer included in the electrode layer formed in the electrode formation step is not particularly limited and may be appropriately selected depending on the purpose, etc. The thickness of the formed electrode layer may be, for example, 0.01 μm to 100 μm, preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 10 μm, for example, 0.3 μm to 3 μm or 1 μm to 5 μm.

[0068] In the electrode formation step, a known plating method can be applied, such as barrel plating, centrifugal plating, rack plating, or the like.

[0069] An example of steps included in a method for manufacturing an electronic component will be described with reference to the drawings. FIG. 2 is a schematic diagram illustrating a portion of the steps of a method for manufacturing an electronic component according to one embodiment of the present invention. In this method, element bodies having a conductive layer on their surfaces are introduced into a tin plating tank 10 by an introduction means 12, and an electrode layer including a tin plating layer is formed on the conductive layer of the element bodies introduced into the tin plating tank. Water evaporates 16 from the tin plating tank 10. Next, the element bodies with the electrode layer formed thereon are pumped out of the tin plating tank by a pumping means 14 into a rinsing tank 20. The rinsing tank 20 may be, for example, a countercurrent multistage rinsing tank. The element bodies are pumped downstream of the countercurrent multistage rinsing tank and move upstream. The element bodies with the electrode layer formed thereon are separated from the countercurrent multistage rinsing tank by a separation means 24 in the most upstream tank. The element bodies with the separated electrode layer formed thereon are then subjected to a drying process. Water is supplied from the upstream side of the countercurrent multistage rinsing tank, which is the rinsing tank 20, by a water supply means 22, and the rinsing water moves downstream. The rinse water (first plating composition) 26 taken out from the most downstream tank is introduced into a plating composition production apparatus 30 .

[0070] In the plating composition manufacturing apparatus 30, at least some of the impurities (e.g., surfactants) are removed from the tin-containing wash water using an impurity removal means (e.g., activated carbon) 32. The wash water from which at least some of the impurities have been removed may be subjected to a concentration process to remove some of the water, if necessary. The wash water from which at least some of the impurities have been removed is introduced into an electrochemical device 34 that includes a working electrode chamber and a counter electrode chamber separated by a membrane. The wash water may contain tin(IV) ions as the first metal ions and may further contain tin(II) ions as the second metal ions. In the electrochemical device 34, at least some of the tin(IV) ions in the wash water are reduced to metallic tin using the working electrode as the cathode. Furthermore, if the wash water contains tin(II) ions, at least some of the tin(II) ions in the wash water may be reduced to metallic tin using the working electrode as the cathode. Next, at least a portion of the reduced tin metal is oxidized to tin(II) ions using the working electrode as the anode, producing a second plating composition 38 that can be reused in plating processes. Additives such as surfactants are added to the produced second plating composition 38 as needed, and the resulting second plating composition is introduced into the tin plating tank 10 for reuse. According to one aspect of this embodiment, tin-containing wash water that would previously have been discarded can be reused as a regenerated plating composition, contributing to a reduction in waste.

[0071] Plating composition manufacturing apparatus The plating composition manufacturing apparatus includes a working electrode chamber containing a first working electrode, and a counter electrode chamber separated from the working electrode chamber by a diaphragm and containing a counter electrode and a counter electrode solution. The plating composition manufacturing apparatus may include a plurality of at least one of the counter electrode chambers and the working electrode chambers. In the plating composition manufacturing apparatus, at least a portion of the counter electrode and the first working electrode may be arranged to face each other alternately with the diaphragm interposed therebetween. The plating composition manufacturing apparatus can be used in the above-mentioned plating composition manufacturing method.

[0072] In one embodiment, the plating composition production apparatus includes a working electrode chamber including a counter electrode chamber containing a counter electrode and a counter electrode solution, and a first working electrode. The working electrode chamber may include a plurality of counter electrode chambers and / or a plurality of first working electrodes. In the working electrode chamber, the counter electrodes and the first working electrodes may be arranged alternately opposite each other with a diaphragm provided in the counter electrode chamber interposed therebetween.

[0073] In another embodiment, the plating composition production apparatus includes a working electrode chamber including a first working electrode, a counter electrode chamber including a counter electrode, and a counter electrode solution. The counter electrode chamber may include a plurality of at least one of the counter electrodes and the working electrode chamber. In the counter electrode chamber, the counter electrodes and the first working electrodes may be arranged alternately opposite each other with a diaphragm provided in the working electrode chamber interposed therebetween.

[0074] The membrane separating the counter electrode and the first working electrode may be one type of membrane selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane.

[0075] The first working electrode may be composed of a single flat plate or a combination of multiple flat plates. The first working electrode may also be composed of a mesh-like conductor, a curved plate-like conductor, or the like, instead of a flat plate. For example, the first working electrode may include a first plate portion and a second plate portion arranged to intersect with the first plate portion. The first plate portion and the second plate portion may be arranged substantially perpendicular to each other, and the second plate portion may be arranged at the lower end of the first plate portion. The first plate portion and the second plate portion may be electrically connected. The first plate portion may be arranged opposite the counter electrode, and the second plate portion may be arranged below the counter electrode chamber. By including the first working electrode in the first plate portion and the second plate portion, metal sludge peeled off from the first plate portion can be collected and efficiently oxidized to second metal ions in the second metal ion oxidation step. Furthermore, the polarity of the first working electrode can be easily switched when switching between the first metal ion reduction step and the second metal ion oxidation step.

[0076] In one aspect, the working electrode chamber may have at least one more first working electrode than the counter electrode chamber, and the counter electrode chamber may be sandwiched between the two first working electrodes. Alternatively, the working electrode chamber may have at least one more counter electrode chamber than the first working electrode, and the first working electrode may be sandwiched between the two counter electrode chambers.

[0077] In one aspect, the working electrode chamber may further include a second working electrode disposed below the counter electrode chamber. The second working electrode may function as an anode together with the first working electrode to oxidize at least a portion of the reduced metal to second metal ions. That is, the second working electrode may function as an anode in the second metal ion oxidation step. By using the second working electrode as an anode, metal sludge peeled from the first working electrode in the second metal ion oxidation step can be efficiently collected and oxidized to second metal ions. The second working electrode may be energized or deenergized during the first metal ion reduction step, and preferably is deenergized. The second working electrode may extend, for example, on the bottom surface of the working electrode chamber. By extending the second working electrode on the bottom surface of the working electrode chamber, metal sludge can be more efficiently collected. Note that when the second working electrode extends on the bottom surface of the working electrode chamber, the first working electrode and the counter electrode chamber are disposed at a distance from the second working electrode extending on the bottom surface of the working electrode chamber.

[0078] In one aspect, the working electrode chamber may have at least two openings connected to a flow path including, for example, a pump for circulating the liquid in the working electrode chamber. Circulating the liquid in the working electrode chamber allows the oxidation-reduction reaction at the first working electrode to occur more uniformly. Of the openings in the working electrode chamber, the opening that absorbs the liquid in the working electrode chamber may be covered with a mesh filter. The mesh filter may be made of, for example, metal and may function as a second working electrode.

[0079] In one aspect, the counter electrode chamber may be configured in a ring shape when viewed from above. When the counter electrode chamber is configured in a ring shape when viewed from above, the counter electrode chamber may be circular or polygonal. The counter electrode chamber configured in a ring shape when viewed from above may be configured as a series of counter electrode chambers, or may be configured as a plurality of counter electrode chambers arranged in a ring. Furthermore, the first working electrode may be arranged in a ring shape along the side surface of the counter electrode chamber. The first working electrode arranged in a ring shape may be configured as a series of conductors, or may be configured as a plurality of conductors arranged in a ring. For example, the counter electrode chamber and the first working electrode may be arranged concentrically and alternately.

[0080] In another aspect, the working electrode chamber may be configured in a ring shape when viewed from above. When the working electrode chamber is configured in a ring shape when viewed from above, the working electrode chamber may be circular or polygonal. The working electrode chamber configured in a ring shape when viewed from above may be configured as a series of working electrode chambers, or may be configured as a plurality of working electrode chambers arranged in a ring. Furthermore, the counter electrode may be arranged in a ring shape along the side surface of the working electrode chamber. The counter electrode arranged in a ring shape may be configured as a series of conductors, or may be configured as a plurality of conductors arranged in a ring. For example, the working electrode chambers and the counter electrode may be arranged alternately in a concentric circle.

[0081] The plating composition manufacturing apparatus may further include an impurity removal means, if necessary. The impurity removal means may include at least a surfactant removal means. Examples of surfactant removal means include activated carbon treatment and gel filtration treatment. The surfactant removal means may preferably include activated carbon treatment. Removal of the surfactant by activated carbon treatment may include, for example, contacting the first plating composition with activated carbon. The use of activated carbon allows for more efficient removal of the surfactant from the first plating composition. The first plating composition may be contacted with activated carbon by, for example, passing the first plating composition through activated carbon held in a cartridge or the like. That is, the regeneration device may include a cartridge filled with activated carbon and configured to allow the first plating composition to pass through. The manufacturing apparatus may further include a power supply, a control device, a temperature control device, etc., that enable electrolysis treatment.

[0082] The invention according to the present disclosure may include, for example, the following aspects: [1] A method for producing a plating composition, comprising: using an electrochemical device including a working electrode chamber containing a first working electrode and a first plating composition, and a counter electrode chamber separated from the working electrode chamber by a diaphragm and containing a counter electrode and a counter electrode solution, reducing at least a portion of first metal ions contained in the first plating composition to a metal using the first working electrode as a cathode, and oxidizing a metal of the same type as the reduced metal to a second metal ion having a lower oxidation number than the first metal ion using the first working electrode as an anode, thereby obtaining a second plating composition containing the second metal ion, wherein the electrochemical device includes a plurality of at least one of the working electrode chambers and the counter electrode chambers, and at least portions of the counter electrode and the first working electrode are arranged to face each other alternately with the diaphragm interposed therebetween.

[0083] [2] The manufacturing method according to [1], wherein the first working electrode comprises a first electrode plate portion and a second electrode plate portion arranged to intersect with the first electrode plate portion, the first electrode plate portion being arranged opposite the counter electrode, and the second electrode plate portion being arranged below the counter electrode chamber.

[0084] [3] The manufacturing method according to [1] or [2], wherein the electrochemical device has at least one more working electrode chamber than the counter electrode, or has at least one more counter electrode chamber than the first working electrode.

[0085] [4] The manufacturing method according to any one of [1] to [3], wherein the electrochemical device further comprises a second working electrode disposed in the working electrode chamber below the counter electrode chamber, and the second working electrode functions as an anode together with the first working electrode to oxidize at least a portion of the reduced metal to second metal ions.

[0086] [5] The manufacturing method according to [4], wherein the second working electrode extends onto a bottom surface of the working electrode chamber.

[0087] [6] The manufacturing method according to [4], wherein the electrochemical device has at least two openings in the working electrode chamber, to which a flow path including a pump for circulating the liquid in the working electrode chamber is connected, and the second working electrode is disposed in a mesh pattern, covering the openings that absorb the liquid in the working electrode chamber.

[0088] [7] The manufacturing method according to any one of [1] to [6], wherein the counter electrode chamber is configured in a ring shape when viewed from above, and the first working electrode is arranged in a ring shape along a side surface of the counter electrode chamber.

[0089] [8] An apparatus for producing a plating composition, comprising: a working electrode chamber having a first working electrode; and a counter electrode chamber arranged to be separated from the working electrode chamber by a diaphragm and having a counter electrode; wherein at least one of the working electrode chambers and the counter electrode chambers is present in plurality; and at least a portion of the first working electrode and the counter electrode are arranged to face each other alternately with the diaphragm interposed therebetween.

[0090] [9] The manufacturing apparatus according to [8], wherein the diaphragm includes one type of membrane selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane.

[0091]

[10] The manufacturing apparatus according to [8] or [9], wherein the first working electrode comprises a first electrode plate portion and a second electrode plate portion arranged to intersect with the first electrode plate portion, the first electrode plate portion is arranged opposite the counter electrode, and the second electrode plate portion is arranged below the counter electrode chamber.

[0092]

[11] The manufacturing apparatus according to any one of claims [8] to

[10] , wherein the working electrode chamber further comprises a second working electrode extending on a bottom surface thereof.

[0093]

[12] The manufacturing apparatus according to any one of [8] to

[10] , wherein the working electrode chamber has at least two openings connected to a flow path including a pump that circulates the liquid in the working electrode chamber, and the apparatus is provided with a second working electrode arranged in a mesh pattern and covering the openings that absorb the liquid in the working electrode chamber.

[0094]

[13] The manufacturing apparatus according to any one of [8] to

[12] , wherein the counter electrode chamber is configured in a ring shape when viewed from above, and the first working electrode is arranged in a ring shape along a side surface of the counter electrode chamber.

[0095] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0096] Preparation of Plating Composition A plating composition having the composition shown below was prepared using purified water, potassium stannate (IV) as a tin (IV) ion source, tin (II) methanesulfonate as a tin (II) ion source, gluconic acid, a cationic surfactant containing decyltrimethylammonium chloride, hydroquinone, and sodium methanesulfonate.

[0097] Composition: Tin (IV) ions: 0.16 mol / L, Tin (II) ions: 0.04 mol / L, Gluconic acid: 0.8 mol / L, Methanesulfonic acid: 1.2 mol / L, Surfactant: 1 g / L, Antioxidant (hydroquinone): 1 g / L, Sodium ions: 1.4 mol / L

[0098] Example 1 The configuration of the electrochemical device included in the plating composition manufacturing apparatus of Example 1 will be described with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing one embodiment of the electrochemical device, taken along a plane parallel to the height direction of the working electrode chamber and perpendicular to the main surfaces of the counter electrode and first working electrode. The electrochemical device 60 includes a counter electrode chamber 66 containing a counter electrode 66 b and a counter electrode solution 66 c, a working electrode chamber 62 including two first working electrodes 64 arranged opposite the counter electrode 66 b via a diaphragm 66 a, and a first plating composition 68 disposed within the working electrode chamber 62. The main surfaces of the counter electrode 66 b and the first working electrodes 64 are arranged alternately opposite each other via the diaphragm 66 a that forms the side surface of the counter electrode chamber 66. In the first metal ion reduction step in the plating composition manufacturing method, the first working electrode 64 serves as an anode and is connected to the negative terminal of a power source, and the counter electrode is connected to the positive terminal of the power source.

[0099] The distance between the principal surfaces of the counter electrode 66b and the first working electrode 64 is 1 mm or more and 200 mm or less. The distance between the principal surface of the first working electrode 64 and the surface of the diaphragm 66a is 0.5 mm or more and 100 mm or less. The distance between the counter electrode 66b and the surface of the diaphragm 66a is 0.5 mm or more and 100 mm or less. The ratio of the distance between the principal surface of the counter electrode 66b and the surface of the diaphragm 66a to the distance between the principal surface of the first working electrode 64 and the surface of the diaphragm 66a is 0.005 or more and 200 or less.

[0100] The plating composition prepared above was passed through an activated carbon cartridge (MX, manufactured by Kankyo Technos Co., Ltd.) attached to a filter at room temperature (25°C) to obtain a first plating composition, which was then introduced into the working electrode chamber of an electrochemical device. The electrochemical device had a platinum-coated titanium electrode (or tin plate electrode) as the first working electrode and a platinum-coated titanium electrode as the counter electrode, and the first working electrode and the counter electrode chamber were separated by a cation exchange membrane (Nafion （ＴＭ） The counter electrode chamber was filled with a 10 g / L aqueous solution of sodium sulfate, and the first working electrode was used as the cathode. The temperature of the solution was between 40 and 70°C, and the current was 0.1 A / dm ２ to 5 A / dm ２Then, the polarity of the power source was switched, and the first working electrode was used as the anode, and the solution temperature was changed from 20°C to 70°C, and the current density was changed to 1 A / dm ２ to 80 A / dm ２ The electrolysis treatment was carried out at a current density of 1000 kJ / min, to obtain a recycled plating composition as the second plating composition.

[0101] In the manufacturing apparatus of Example 1, the first working electrode and the counter electrode are alternately arranged, so that the two main surfaces of the counter electrode can be used as reaction surfaces, thereby increasing the reaction area and improving the reaction efficiency. In addition, the multi-layer structure allows the area per layer to be reduced, improving the ease of handling of the electrodes and further contributing to the miniaturization of the manufacturing apparatus.

[0102] Example 2 A second plating composition was obtained in the same manner as in Example 1, except that the manufacturing apparatus was changed to an electrochemical apparatus having the configuration shown in the schematic cross-sectional view of FIG.

[0103] In the electrochemical device 100 of Example 2, two counter electrode chambers 106 containing a counter electrode 106b and a counter electrode solution 106c are arranged in the working electrode chamber 102 with the principal surfaces of the counter electrodes 106b facing each other. The two counter electrode chambers 106 are alternately sandwiched between three first working electrodes 104. The principal surfaces of the first working electrodes 104 and the principal surfaces of the counter electrodes 106b are alternately arranged facing each other with diaphragms 106a interposed therebetween. A first plating composition 108 is arranged in the working electrode chamber 102.

[0104] In the production apparatus of Example 2, three first working electrodes and two counter electrodes are alternately arranged, so that two main surfaces of the counter electrodes and two main surfaces of the first working electrodes can be used as reaction surfaces, thereby increasing the reaction area and improving the reaction efficiency. Furthermore, the multi-layer structure allows the area per layer to be reduced, improving the ease of handling of the electrodes and further contributing to the miniaturization of the production apparatus.

[0105] Example 3 A second plating composition was obtained in the same manner as in Example 1, except that the manufacturing apparatus was changed to an electrochemical apparatus having the configuration shown in the schematic cross-sectional view of FIG.

[0106] In the electrochemical device of Example 3, two counter electrode chambers 106 containing a counter electrode 106b and a counter electrode solution 106c are arranged in the working electrode chamber 102 with the main surfaces of the counter electrodes 106b facing each other. The two counter electrode chambers 106 are alternately sandwiched between three first working electrodes 114. The first working electrode 114 has a first electrode plate portion 114a and a second electrode plate portion 114b arranged at the lower end of the first electrode plate portion 114a and substantially perpendicular to the first electrode plate portion 114a. The second electrode plate portion 114b is arranged below the bottom surface of the counter electrode chamber 106. The second electrode plate portion 114b extends from the first electrode plate portion 114a to a portion of the bottom surface of the counter electrode chamber 106. The main surfaces of the first electrode plate portions 114a of the first working electrodes 114 and the main surfaces of the counter electrodes 106b are arranged alternately facing each other with the diaphragm 106a interposed therebetween. A first plating composition 108 is disposed in the working electrode chamber 102 .

[0107] In the manufacturing apparatus of Example 3, the first working electrode has a second plate portion, which increases the reaction area. Furthermore, when the first working electrode is used as the anode in the second metal ion oxidation step of the manufacturing method of the plating composition, metal sludge that may be generated can be collected in the second plate portion, and the collected metal sludge is oxidized in the second plate portion to generate second metal ions, thereby further improving the recovery rate of the first metal ions.

[0108] Example 4 A second plating composition was obtained in the same manner as in Example 1, except that the manufacturing apparatus was changed to an electrochemical apparatus having the configuration shown in the schematic cross-sectional view of FIG.

[0109] The electrochemical device of Example 4 has the same configuration as the electrochemical device of Example 2, except that a second working electrode 124 is disposed below the first working electrode 104 and the counter electrode chamber 106, which are disposed in the working electrode chamber 102. The second working electrode 124 extends along the bottom surface of the working electrode chamber 102, spaced apart from the first working electrode 104 and the counter electrode chamber 106. The second working electrode 124 is not connected to a power source in the first metal ion reduction step of the manufacturing method, but is connected to a power source as an anode in the second metal ion oxidation step.

[0110] In the manufacturing apparatus of Example 4, when the first working electrode is used as the anode in the second metal ion oxidation step of the manufacturing method of the plating composition, metal sludge that may be generated can be recovered on the second working electrode, and the recovered metal sludge is oxidized at the second working electrode to generate second metal ions, thereby further improving the recovery rate of the first metal ions.

[0111] Example 5 A second plating composition was obtained in the same manner as in Example 1, except that the manufacturing apparatus was changed to an electrochemical apparatus having the configuration shown in the schematic cross-sectional view of FIG.

[0112] The electrochemical device of Example 5 is configured similarly to the electrochemical device of Example 2, except that it has at least two openings 102a, 102b near the bottom of the working electrode chamber 102, to which a flow path 112 including a pump P for circulating the liquid 108 in the working electrode chamber 102 is connected. The working electrode chamber 102 has an opening 102a on the liquid absorption side and an opening 102b on the liquid delivery side, and the two openings are connected by a flow path 112 located outside the working electrode chamber 102. The flow path 112 is equipped with a pump P to circulate the liquid 108 in the working electrode chamber 102. The opening on the liquid absorption side is covered with a filter 134 to prevent solid matter from entering the flow path. The filter 134 has a mesh structure and is made of a conductive metal. The filter 134 is not connected to a power source during the first metal ion reduction step of the production method, but is connected to a power source as an anode during the second metal ion oxidation step, functioning as a second working electrode.

[0113] In the production apparatus of Example 5, the liquid in the working electrode chamber is circulated by a pump, which can suppress the occurrence of a concentration gradient of metal ions that may form near the first working electrode. This allows the oxidation-reduction reaction at the first working electrode to occur more uniformly. Furthermore, metal sludge that may be generated in the second metal ion oxidation step is collected by a filter and oxidized on the filter to generate second metal ions, which can further improve the recovery rate of the first metal ions.

[0114] Example 6 A second plating composition was obtained in the same manner as in Example 1, except that the manufacturing apparatus was changed to an electrochemical apparatus having the configuration shown in the schematic top view of FIG.

[0115] The electrochemical device 200 of Example 6 is configured similarly to the electrochemical device of Example 2, except that the working electrode chamber 202 has a cylindrical shape, and the first working electrodes 204, 214, 224, the counter electrode chambers 206, 216, and the counter electrodes 206b, 216b each have a concentric ring shape in a top view and extend along the height direction of the working electrode chamber 202. In the electrochemical device 200, the first working electrode 204, the counter electrode chamber 206, the first working electrode 214, the counter electrode chamber 216, and the first working electrode 224 are alternately arranged in this order from the outer edge of the working electrode chamber 202. The counter electrode chamber 206 contains a counter electrode solution 206c and a counter electrode 206b. The main surface of the counter electrode 206b is arranged to alternately face the main surfaces of the first working electrode 204 and the first working electrode 214, with a diaphragm 206a interposed therebetween. Counter electrode chamber 216 contains counter electrode solution 216c and counter electrode 216b. The main surfaces of counter electrodes 216b are arranged to alternately face the main surfaces of first working electrodes 214 and first working electrodes 224 with diaphragms 216a interposed therebetween.

[0116] In the production apparatus of Example 6, the areas of the first working electrode and the counter electrode can be made larger relative to the area occupied by the working electrode chamber in a top view, thereby improving reaction efficiency. Furthermore, the multi-layer structure allows the area per layer to be reduced, improving the ease of handling the electrodes and contributing to the miniaturization of the production apparatus.

[0117] The above describes embodiments and variants of the present invention, but the disclosed contents may vary in details of the configuration, and changes in the combination and order of elements in the embodiments and variants may be realized without departing from the scope and spirit of the claimed disclosure.

[0118] The disclosure of Japanese Patent Application No. 2024-016135 (filing date: February 6, 2024) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing a plating composition, comprising: using an electrochemical device comprising a working electrode chamber containing a first working electrode and a first plating composition, and a counter electrode chamber separated from the working electrode chamber by a diaphragm and containing a counter electrode and a counter electrode solution, reducing at least a portion of first metal ions contained in the first plating composition to a metal using the first working electrode as a cathode; and oxidizing a metal of the same type as the reduced metal to a second metal ion having a lower oxidation number than the first metal ion using the first working electrode as an anode, thereby obtaining a second plating composition containing the second metal ion, wherein the electrochemical device comprises a plurality of at least one of the working electrode chambers and the counter electrode chambers, and at least a portion of the counter electrodes and the first working electrodes are arranged alternately opposite each other with the diaphragm interposed therebetween.

2. The manufacturing method described in claim 1, wherein the first working electrode comprises a first plate portion and a second plate portion arranged to intersect with the first plate portion, the first plate portion being arranged opposite the counter electrode, and the second plate portion being arranged below the counter electrode chamber.

3. The manufacturing method according to claim 1 or 2, wherein the electrochemical device has at least one more working electrode chamber than the counter electrode, or at least one more counter electrode chamber than the first working electrode.

4. The manufacturing method according to any one of claims 1 to 3, wherein the electrochemical device further comprises a second working electrode disposed in the working electrode chamber below the counter electrode chamber, and the second working electrode functions as an anode together with the first working electrode to oxidize a metal of the same type as the reduced metal to a second metal ion.

5. The method of claim 4, wherein the second working electrode extends onto a bottom surface of the working electrode chamber.

6. The manufacturing method according to claim 4, wherein the electrochemical device has at least two openings in the working electrode chamber to which a flow path including a pump for circulating the liquid in the working electrode chamber is connected, and the second working electrode is arranged in a mesh pattern, covering the openings that absorb the liquid in the working electrode chamber.

7. A manufacturing method according to any one of claims 1 to 6, wherein the counter electrode chamber is configured in a ring shape when viewed from above, and the first working electrode is arranged in a ring shape along the side surface of the counter electrode chamber.

8. An apparatus for producing a plating composition, comprising: a working electrode chamber having a first working electrode; and a counter electrode chamber having a counter electrode, the working electrode chamber being separated from the working electrode chamber by a diaphragm; wherein at least one of the working electrode chambers and the counter electrode chambers exists in plurality; and at least a portion of the first working electrode and the counter electrode are arranged to face each other alternately with the diaphragm interposed therebetween.

9. The manufacturing apparatus according to claim 8, wherein the diaphragm comprises one type of membrane selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane.

10. A manufacturing apparatus as described in claim 8 or 9, wherein the first working electrode comprises a first electrode plate portion and a second electrode plate portion arranged to intersect with the first electrode plate portion, the first electrode plate portion being arranged opposite the counter electrode, and the second electrode plate portion being arranged below the counter electrode chamber.

11. The manufacturing apparatus according to any one of claims 8 to 10, wherein the working electrode chamber further comprises a second working electrode extending onto a bottom surface thereof.

12. A manufacturing apparatus according to any one of claims 8 to 10, wherein the working electrode chamber has at least two openings connected to a flow path including a pump for circulating the liquid in the working electrode chamber, and a second working electrode is provided which is arranged in a mesh pattern and covers the openings that absorb the liquid in the working electrode chamber.

13. A manufacturing apparatus according to any one of claims 8 to 12, wherein the counter electrode chamber is configured in a ring shape when viewed from above, and the first working electrode is arranged in a ring shape along the side surface of the counter electrode chamber.

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