Method and device for regenerating plating composition

Abstract

Provided is a method for regenerating a plating composition, whereby metal ions in a highly oxidized state in the plating composition can be effectively reduced to metal ions in a low oxidized state. The method for regenerating a plating composition includes: removing at least a portion of a surfactant from a plating composition including tin (IV) ions and the surfactant; the plating composition from which at least a portion of the surfactant has been removed is introduced into a working electrode chamber provided with a working electrode and isolated from a counter electrode chamber provided with a counter electrode by one membrane selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane, and the working electrode is used as a cathode. Reducing at least a portion of the tin (IV) ions in the introduced plating composition to metallic tin; and oxidizing at least a portion of the reduced metallic tin into tin (II) ions using the working electrode as an anode.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for regenerating a plating composition. Background Art

[0002] Regarding the plating composition for metal plating, Japanese Patent Publication No. 2004-534151 proposes a method for regenerating a plating solution by reducing tin (IV) ions to tin (II) ions using electrolytically precipitated tin. In addition, Japanese Patent Publication No. 2015-518923 proposes a method for regenerating a plating composition by oxidizing and reducing two metal components in the plating composition using an apparatus having a working electrode chamber, a counter electrode chamber, and an ion exchange membrane separating them. Summary of the invention

[0003] One aspect of the present invention is to provide a method for regenerating a plating composition that can effectively reduce metal ions in a high oxidation state in the plating composition to metal ions in a low oxidation state.

[0004] The first aspect is a method for regenerating a plating composition, comprising: a step of removing at least a portion of the surfactant from a plating composition comprising tin (IV) ions and a surfactant; introducing the plating composition from which at least a portion of the surfactant has been removed into a working electrode chamber having a working electrode and which is isolated from a counter electrode chamber having a counter electrode by a membrane selected from an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane, and reducing at least a portion of the tin (IV) ions in the introduced plating composition into metallic tin using the working electrode as a cathode; and a step of oxidizing at least a portion of the reduced metallic tin into tin (II) ions using the working electrode as an anode.

[0005] The second aspect is a regeneration device for the plating composition, which comprises: a surfactant removal mechanism, a working electrode chamber having a working electrode, a counter electrode chamber having a counter electrode, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane that separates the working electrode chamber and the counter electrode chamber.

[0006] According to one aspect of the present invention, a method for regenerating a plating composition capable of effectively reducing metal ions in a high oxidation state in the plating composition to metal ions in a low oxidation state can be provided. DETAILED DESCRIPTION

[0007] In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In addition, for the content of each component in the composition, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition. Furthermore, the upper and lower limits of the numerical ranges described in this specification can be arbitrarily selected and combined as numerical values ​​exemplified by the numerical range. Below, embodiments of the present invention are described in detail. However, the embodiments shown below illustrate the regeneration method and regeneration device of the plating composition for concretizing the technical idea of ​​the present invention, and the present invention is not limited to the regeneration method and regeneration device of the plating composition shown below.

[0008] Method for regenerating plating composition

[0009] The regeneration method of a plating composition comprises: a first step of removing at least a portion of a surfactant from a plating composition comprising tin (IV) ions and a surfactant; a second step of introducing the plating composition from which at least a portion of the surfactant has been removed into a working electrode chamber having a working electrode and which is isolated from a counter electrode chamber having a counter electrode by a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane, and reducing at least a portion of the tin (IV) ions in the introduced plating composition to metallic tin using the working electrode as a cathode; and a third step of oxidizing at least a portion of the reduced metallic tin to tin (II) ions using the working electrode as an anode.

[0010] After removing at least a portion of the surfactant from the plating composition, an electrochemical device having a counter electrode chamber and a working electrode chamber separated by a membrane that is not easily permeable to tin ions, such as an ion exchange membrane, is used to electrochemically reduce the tin (IV) ions, thereby effectively reducing the tin (IV) ions to metallic tin. This can be considered as follows, for example. It is believed that by removing at least a portion of the surfactant contained in the plating composition, the interaction between the surfactant and the cathode is suppressed to hinder the reduction of the tin (IV) ions, and the reduction efficiency of the tin (IV) ions in the cathode is improved.

[0011] In the first step, at least a portion of the surfactant is removed from a plating composition comprising tin (IV) ions and a surfactant. The plating composition may be an electrolytic plating solution or an electroless plating solution. The plating composition may preferably be an electrolytic plating solution or an electrolytic tin plating solution, and more preferably may be a used electrolytic tin plating solution. The plating composition may be a plating composition in which at least tin (IV) ions and a surfactant are dissolved in a liquid medium. The liquid medium constituting the plating composition may contain at least water, and in addition to water, may further contain a water-soluble organic solvent or the like as required.

[0012] The surfactant contained in the plating composition may be any one of a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, etc. In addition, the surfactant may function as a so-called glossing agent, a leveling agent, etc. in the plating composition. From the viewpoint of the reduction efficiency of tin (IV) ions, the surfactant may include at least one selected from a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. The surfactant contained in the plating composition may be only one kind or a combination of two or more kinds.

[0013] Examples of the nonionic surfactant include ester-type surfactants formed by ester bonding of polyols such as glycerol, sorbitol, and sucrose with fatty acids; ether-type surfactants formed by adding ethylene oxide, propylene oxide, etc. to compounds having hydroxyl groups such as higher alcohols and alkylphenols; and ester-ether-type surfactants formed by adding ethylene oxide, propylene oxide, etc. to ester-type surfactants. Specific examples of the nonionic surfactant include polyethylene glycol, polypropylene glycol, polyoxyethylene octylphenol, polyoxyethylene β-naphthyl ether, polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerol fatty acid ester and ethylene oxide adducts thereof, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid monoethanolamide and ethylene oxide adducts thereof, fatty acid-N-methyl monoethanolamide and ethylene oxide adducts thereof, fatty acid diethanolamide and ethylene oxide adducts thereof, sucrose fatty acid ester, alkyl (poly) glycerol ether, polyglycerol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid methyl ester ethoxylate, N-long chain alkyl dimethyl amine oxide, etc. The nonionic surfactant may be substituted with fluorine atoms in these structures.

[0014] Examples of the cationic surfactant include amine salts and quaternary ammonium salts. Specifically, examples of the cationic surfactant include alkyl (or alkenyl) trimethylammonium salts, alkyl (or alkenyl) triethylammonium salts, dialkyl (or alkenyl) dimethylammonium salts, alkyl (or alkenyl) quaternary ammonium salts, mono- or di-alkyl (or alkenyl) quaternary ammonium salts containing ether groups, ester groups or amide groups, alkyl (or alkenyl) pyridines, Salt, alkyl (or alkenyl) dimethylbenzylammonium salt, alkyl (or alkenyl) isoquinoline Salt, dialkyl (or alkenyl) morpholine 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. The cationic surfactants may be substituted with fluorine atoms in these structures.

[0015] Amphoteric surfactants show the properties of anionic surfactants in the alkaline region and the properties of cationic surfactants in the acidic region. Examples of amphoteric surfactants include carboxylates, sulfonates, and the like, and may be any of amino acid type and betaine type. Examples of amphoteric surfactants include alkyl dimethylaminoacetic acid betaine, alkyl dimethylacetic acid betaine, alkyl dimethylcarboxy betaine, alkyl dimethylcarboxy methylene ammonium betaine, alkyl dimethyl ammonium acetate, fatty acid amide propyl dimethyl amino acid betaine, alkanoyl amide propyl dimethyl glycine, 2-alkyl-1-(2-hydroxyethyl) imidazole. -1-acetate, alkyldiaminoethylglycine, dialkyldiaminoethylglycine, alkyldimethylamine oxide, etc.

[0016] Examples of the anionic surfactant include carboxylates, sulfonates, sulfate ester salts, and phosphate ester salts.

[0017] The content of the surfactant in the plating composition may be, for example, 0.01 g / L to 10 g / L, preferably 0.1 g / L or more or 5 g / L or less. The content of the surfactant in the plating composition after removal in the first step may be, for example, 0.005 g / L or more. It should be noted that the content of the surfactant may be measured by using the surface tension as an index. Specifically, it may be measured using a drop weight meter.

[0018] The tin (IV) ions contained in the plating composition may be derived from, for example, a water-soluble tin (IV) salt, or may be generated by oxidation of the tin (II) ions constituting the plating composition before use. In addition, the tin (IV) ions contained in the plating composition may be simple metal ions or complex ions. As complexing agents for forming complex ions, for example, carboxylic acids including gluconic acid (including gluconolactone), citric acid, glutaric acid, succinic acid, malic acid, tartaric acid, lactic acid and their salts or derivatives may be cited; phosphoric acids including tripolyphosphoric acid, hydroxyethane diphosphonic acid and their salts; sugars including sorbitol, mannitol and their salts; amino acids including phenylalanine, glutamic acid, aspartic acid, alanine, glycine and their salts; HEDTA, EDTA, etc. The complexing agent may include at least one selected from them, and may include at least gluconic acid. The complexing agent may be used alone or in combination of two or more. When the tin (IV) ions are complex ions, the pH of the plating composition can be set to weak acidity or alkalinity, and corrosion of plated objects that are weak to strong acids or alkalis (for example, articles using oxides as components such as ceramic capacitors) can be suppressed.

[0019] The content of tin (IV) ions contained in the plating composition may be, for example, 0.1 g / L to 100 g / L, preferably 1 g / L or more. In addition, the content of the complexing agent contained in the plating composition may be, for example, equimolar to 20 times the molar content of the tin ions, preferably 10 times or less. It should be noted that the content of tin (IV) ions contained in the plating composition may be measured, for example, by high-frequency inductively coupled plasma emission spectrometry (ICP-AES) or by redox titration using potassium iodate after reduction with iron powder.

[0020] In addition to tin (IV) ions, the plating composition may also include tin (II) ions. Tin (II) ions may be simple metal ions or complex ions. The complexing agent forming the complex ions is the same as the tin (IV) ions. When the plating composition includes tin (II) ions, the content of the tin (II) ions contained in the plating composition may be, for example, less than 100 g / L, preferably less than 20 g / L. It should be noted that the content of the tin (II) ions contained in the plating composition is measured in the same manner as the tin (IV) ions.

[0021] The source of tin (II) ions can be any water-soluble tin (II) salt. Specifically, water-soluble tin (II) salts include, for example, stannous sulfate, stannous chloride, tin borofluoride, tin (II) alkanesulfonate, tin (II) alkaneolsulfonate, tin (II) aromatic sulfonate, etc., and may include at least one selected from them, and may include at least tin (II) alkanesulfonate. As the alkanesulfonic acid in the alkanesulfonic acid tin (II), for example, alkanesulfonic acid having 1 to 3 carbon atoms can be mentioned, specifically, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, 2-propanesulfonic acid, etc.

[0022] In addition to tin ions, the plating composition may further contain other metal ions other than tin. Examples of other metal ions include salts of lead ions, copper ions, silver ions, bismuth ions, cobalt ions, nickel ions, and the like.

[0023] The plating composition may further contain alkali metal ions, ammonium ions, etc. By containing alkali metal ions, ammonium ions, etc., there is a tendency that the conductivity becomes higher, the heat caused by the solution resistance during electrolytic plating is suppressed, and the uniform electrodeposition is improved. As alkali metal ions, lithium ions, sodium ions, potassium ions, rubidium, cesium, etc. can be mentioned. Alkali metal ions, ammonium ions, etc. can be added to the plating composition, for example, in the form of salts with acid components. By including an acid component in the plating composition, for example, the stability of the plating composition is further improved. As an acid component, for example, sulfuric acid, hydrochloric acid, alkane sulfonic acid, alkanol sulfonic acid, aromatic sulfonic acid, phosphoric acid, alkyl carboxylic acid, aryl carboxylic acid, etc. can be mentioned, and at least one selected from them can be included. These acids can be used alone or in combination of two or more.

[0024] The pH of the plating composition may be, for example, 1 to 13, preferably 3 or more or 4 or more, and preferably 11 or less or 9 or less. When the pH of the plating composition is within the above range, there is a tendency to more effectively reduce tin (IV) ions. The pH of the plating composition may be adjusted to a desired range using a pH adjuster, for example, in addition to the above acid components, alkali metal hydroxides, ammonia, etc. may also be mentioned.

[0025] The plating composition may further include an antioxidant. By including an antioxidant, for example, the stability of the plating composition is improved and the bath life can be extended. As antioxidants, for example, hydroquinone, ascorbic acid, catechol, hypophosphorous acid, isoascorbic acid, etc. can be cited. In the case where the plating composition includes an antioxidant, the content of the antioxidant contained in the plating composition can be, for example, 0.01 g / L to 20 g / L, preferably 0.1 g / L or more or 5 g / L or less.

[0026] In the case where the plating composition includes an antioxidant, the first step may include removing at least a portion of the antioxidant. The removal of the antioxidant may be performed by an activated carbon treatment.

[0027] As a method for removing the surfactant in the first step, for example, activated carbon treatment, gel filtration treatment, etc. can be cited. The method for removing the surfactant in the first step preferably includes activated carbon treatment. The method for removing the surfactant by activated carbon treatment may, for example, include contacting the plating composition with activated carbon. By using activated carbon, at least a portion of the surfactant can be more effectively removed from the plating composition. In the first step, a method for electrostatically adsorbing the surfactant (for example, a method for contacting with an ion exchange resin) and activated carbon treatment can be combined.

[0028] Activated carbon is a porous material that has carbon as its main component and has been chemically or physically activated. The activated carbon used in activated carbon treatment can be chemically activated or gas activated. In addition, the activated carbon can be powdered activated carbon, granular activated carbon, or a combination thereof.

[0029] The specific surface area of ​​activated carbon can be, for example, 200 m 2 / g~1500m 2 / g, preferably 300m 2 / g or above or 700m 2 / g or less. It should be noted that the specific surface area is based on the BET (Brunauer Emmett Teller) theory, and is measured using nitrogen after heat treatment at 200°C for 6 hours as a pretreatment. In addition, the average pore diameter of the activated carbon can be, for example, 1.5nm to 3.5nm, and preferably 2.0nm to 3.0nm. For the mesoporous shape of the activated carbon, the average pore width on the adsorption side based on the INNES method can be, for example, 2nm to 30nm, and preferably 4nm to 10nm. In addition, the average pore width on the desorption side based on the INNES method can be, for example, 2nm to 5nm, and preferably 2nm to 3.5nm.

[0030] The amount of activated carbon used for contacting the plating composition can be appropriately selected according to the type of activated carbon. The amount of activated carbon used can be an amount that can remove at least a portion of the surfactant contained in the plating composition, preferably an amount sufficient to remove 50% by mass, 70% by mass or more, or 90% by mass or more of the surfactant. The amount of activated carbon used can be selected according to the contact method with the plating composition. For example, in the case of a one-time contact, the amount of activated carbon required can be increased compared to the case of circulating the plating composition.

[0031] The contact between the plating composition and the activated carbon can be achieved, for example, by mixing the plating composition and the activated carbon and then performing solid-liquid separation, or by allowing the plating composition to contact the activated carbon by passing through a filter, a filter cartridge, etc. The contact temperature between the plating composition and the activated carbon can be, for example, 0°C or higher or 70°C or lower.

[0032] In the second step, the plating composition from which at least a portion of the surfactant has been removed is introduced into a working electrode chamber of an electrochemical device having a working electrode chamber with a working electrode and a counter electrode chamber with a counter electrode, and the working electrode chamber and the counter electrode chamber are separated by a membrane selected from an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane, and at least a portion of the tin (IV) ions in the introduced plating composition are reduced to metallic tin using the working electrode as a cathode. An aqueous solution containing conductive ions can be configured in the counter electrode chamber of the electrochemical device. By configuring an aqueous solution containing conductive ions in the counter electrode chamber, tin (IV) ions can be more effectively reduced.

[0033] As the material of the working electrode in the working electrode chamber, for example, gold, platinum, platinum-coated titanium, silver, nickel, graphite, tin, titanium, iridium oxide, etc. can be cited. As the material of the counter electrode, platinum, platinum-coated titanium, gold, nickel, iridium oxide, titanium, graphite, palladium, etc. can be cited. The working electrode chamber and the counter electrode chamber are separated by an ion exchange membrane. Thus, the tin (IV) ions can be reduced more effectively. The ion exchange membrane can be a cation exchange membrane, can be an anion exchange membrane, or can be used in combination with the two. The ion exchange membrane can be appropriately selected from the ion exchange membranes that can be purchased for use. From the viewpoint of the reduction efficiency of tin (IV) ions, the ion exchange membrane can at least include a cation exchange membrane. For example, the cation exchange membrane can include a copolymer of a fluorine resin based on sulfonated tetrafluoroethylene. In addition, for example, a reverse osmosis membrane (RO membrane), a nanofiltration membrane (NF membrane, loose RO membrane), etc., which are not easy to pass through tin ions, can be used instead of the ion exchange membrane.

[0034] When an aqueous solution containing conductive ions is disposed in the counter electrode chamber, the aqueous solution containing conductive ions may contain at least water and a water-soluble metal salt. The water-soluble metal salt may contain, for example, alkali metal ions, alkaline earth metal ions, etc. as metal ions. In addition, the water-soluble metal salt may contain, for example, sulfate ions, nitrate ions, phosphate ions, etc. as anions.

[0035] In the second step, at least a portion of the tin (IV) ions in the plating composition introduced into the working electrode chamber is subjected to a first electrolytic treatment using the working electrode as a cathode, thereby reducing the tin (IV) ions to metallic tin. The metallic tin generated by the reduction can be deposited on the working electrode, for example. The current density during the electrolysis of the tin (IV) ions can be, for example, 0.05 A / dm 2 ~1A / dm 2 , preferably 0.1A / dm 2 Above or 0.5A / dm 2 The temperature during electrolysis may be, for example, 30° C. to 80° C., preferably 35° C. or higher or 75° C. or lower. The time required for electrolysis may be, for example, 10 minutes to 200 hours.

[0036] In the third step, at least a portion of the metal tin generated by reduction in the second step is subjected to a second electrolytic treatment using the working electrode as an anode, thereby oxidizing it to tin (II) ions. In the third step, the metal tin deposited on the working electrode in the second step can be electrolyzed and oxidized to tin (II) ions using the working electrode as an anode. That is, the third step can be implemented using the same electrochemical device after the reduction of the tin (IV) ions in the second step.

[0037] The current density during electrolysis of metallic tin can be, for example, 0.5 A / dm 2 ~100A / dm 2The temperature during electrolysis of metal tin may be, for example, 10° C. to 80° C., preferably 15° C. or higher or 75° C. or lower. The time required for electrolysis may be, for example, 0.2 hours to 10 hours.

[0038] The regeneration method of the plating composition may further include a step of adding a surfactant to the plating composition after the third step. By using the plating composition to which the surfactant is added, a plating with a better surface is formed. The added surfactant may be the same as the surfactant removed in the first step. In addition, the amount of surfactant added may be the same as the amount removed in the first step.

[0039] Device for regenerating plating composition

[0040] The plating composition regeneration device comprises: a surfactant removal mechanism, a working electrode chamber having a working electrode, a counter electrode chamber having a counter electrode, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane for isolating the working electrode chamber and the counter electrode chamber. The plating composition regeneration device can be used in the above-mentioned plating composition regeneration method.

[0041] As the surfactant removal mechanism possessed by the regeneration device, for example, activated carbon treatment, gel filtration treatment, etc. can be cited. The surfactant removal mechanism preferably includes activated carbon treatment. Removing the surfactant by activated carbon treatment may include, for example, contacting the plating composition with activated carbon. By using activated carbon, the surfactant can be more effectively removed from the plating composition. Contacting the plating composition with activated carbon can, for example, allow the plating composition to contact with activated carbon held in a filter cartridge or the like. That is, the regeneration device may also be provided with a filter cartridge configured to be filled with activated carbon and through which the plating composition can pass.

[0042] The regeneration device may include an electrochemical device that is configured to include a working electrode chamber, a counter electrode chamber, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane that separates the working electrode chamber and the counter electrode chamber, and can perform electrolysis. The regeneration device may further include a power supply device, a control device, a temperature control device, etc. that can perform electrolysis.

[0043] The present invention may include the following aspects.

[0044] <1> A method for regenerating a plating composition, comprising: a step of removing at least a portion of the surfactant from a plating composition comprising tin (IV) ions and a surfactant; introducing the plating composition from which at least a portion of the surfactant has been removed into a working electrode chamber having a working electrode and isolated from a counter electrode chamber having a counter electrode by a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane, and reducing at least a portion of the tin (IV) ions in the introduced plating composition into metallic tin using the working electrode as a cathode; and a step of oxidizing at least a portion of the reduced metallic tin into tin (II) ions using the working electrode as an anode.

[0045] <2> The regeneration method according to <1>, wherein at least a portion of the tin (IV) ions forms a tin (IV) gluconate complex.

[0046] <3> The regeneration method according to <1> or <2>, wherein the ion exchange membrane is a cation exchange membrane.

[0047] <4> The regeneration method according to any one of <1> to <3>, wherein the pH of the working electrode chamber is 1 to 13.

[0048] <5> The regeneration method according to any one of <1> to <4>, wherein the counter electrode chamber comprises an aqueous solution containing conductive ions.

[0049] <6> The regeneration method according to any one of <1> to <5>, wherein the step of removing at least a portion of the surfactant from the plating composition includes contacting the plating composition with activated carbon.

[0050] <7> The regeneration method according to any one of <1> to <6>, wherein the surfactant includes at least one selected from a nonionic surfactant and a cationic surfactant.

[0051] <8> The regeneration method according to any one of <1> to <7>, wherein the plating composition contains an antioxidant.

[0052] <9> A regeneration device for a plating composition, comprising: a surfactant removal mechanism, a working electrode chamber having a working electrode, a counter electrode chamber having a counter electrode, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane for isolating the working electrode chamber and the counter electrode chamber.

[0053] <10> A use of a regeneration device for a plating composition, which is the use of the regeneration device for a plating composition in a regeneration method for a plating composition described in any one of <1> to <8>, wherein the regeneration device for the plating composition comprises: a surfactant removal mechanism, a working electrode chamber having a working electrode, a counter electrode chamber having a counter electrode, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane for isolating the working electrode chamber and the counter electrode chamber.

[0054] Example

[0055] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0056] Reference example

[0057] Preparation of plating compositions

[0058] A plating composition having the following composition 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.

[0059] Tin (IV) ion: 0.16 mol / L

[0060] Tin (II) ion: 0.04 mol / L

[0061] Gluconic acid: 0.8 mol / L

[0062] Methanesulfonic acid: 1.2 mol / L

[0063] Surfactant: 1g / L

[0064] Hydroquinone: 1g / L

[0065] Sodium ion: 1.4 mol / L

[0066] Example 1

[0067] 2L of the plating composition prepared above was passed through an activated carbon cartridge (made by Kankyo Technos Co., Ltd.; MX) installed in a filter at room temperature (25°C) and introduced into the working electrode chamber of the electrochemical device. The electrochemical device was equipped with a platinum-coated titanium electrode as a working electrode and a platinum-coated titanium electrode as a counter electrode. The working electrode chamber and the counter electrode chamber were connected by a cation exchange membrane (Noafion (TM) 424) isolation. Add 10g / L sodium sulfate aqueous solution to the counter electrode chamber of the electrolysis device, use the working electrode as the cathode, and at a liquid temperature of 40℃ to 70℃, at 0.1A / dm 2 ~0.5A / dm 2The electrolysis was carried out at a current density of 36.1 A for 1 hour. Then, the working electrode was used as the anode and the solution temperature was 20°C to 70°C at 1 A / dm 2 ~80A / dm 2 The electrolytic treatment was carried out at a current density of 34.3 A for 0.5 hours to obtain a regenerated plating composition as the treated plating composition.

[0068] For the regenerated plating composition, the concentrations of tin (IV) ions and tin (II) ions were evaluated by combining redox titration and high-frequency inductively coupled plasma emission spectrometry (ICP-AES). Specifically, as a redox titration, starch was used as an indicator and titrated with an iodine standard solution in 2M hydrochloric acid to calculate the concentration of tin (II) ions. In addition, the total concentration of tin ions was calculated using ICP-AES, and the concentration of tin (II) ions was subtracted to calculate the concentration of tin (IV) ions.

[0069] As a result, in the regenerated plating composition, the concentration of tin (IV) ions was 0.04 mol / L, and the concentration of tin (II) ions was 0.16 mol / L. Based on this result, the reduction efficiency of tin (IV) ions was evaluated to be 95%. It should be noted that the reduction efficiency is calculated by dividing the cumulative current value in the third step by 1 / 2 of the cumulative current value in the second step.

[0070] Here, the specific surface area of ​​the activated carbon contained in the activated carbon cartridge (MX) based on the BET method is 437 m 2 / g, and the average pore diameter was 2.4 nm. In terms of the mesopore shape, the average pore width on the adsorption side based on the INNES method was 6.0 nm, and the average pore width on the desorption side was 2.1 nm.

[0071] In addition, even when the activated carbon cartridge was changed to YCC-R manufactured by Nihon Filter Co., Ltd., the same results were obtained.

[0072] The specific surface area of ​​the activated carbon contained in the activated carbon cartridge (YCC-R) based on the BET method is 1237 m 2 / g, and the average pore diameter was 1.8 nm. In terms of the mesopore shape, the average pore width on the adsorption side based on the INNES method was 2.5 nm, and the average pore width on the desorption side was 4.0 nm.

[0073] Comparative Example 1

[0074] The electrolytic treatment was performed twice in the same manner as in Example 1, except that the plating composition was directly introduced into the working electrode chamber without passing through the activated carbon cartridge, to obtain a treated plating composition.

[0075] The concentrations of tin (IV) ions and tin (II) ions in the treated plating composition were similarly evaluated. The concentration of tin (IV) ions was 0.19 mol / L and the concentration of tin (II) ions was 0.01 mol / L. Based on these results, the reduction efficiency of tin (IV) ions was evaluated to be 0%.

[0076] Comparative Example 2

[0077] The electrolysis treatment was performed twice in the same manner as in Example 1, except that the electrolysis apparatus was used in which the working electrode chamber and the counter electrode chamber were not separated by a cation exchange membrane but could flow liquid to each other, thereby obtaining a treated plating composition.

[0078] The concentrations of tin (IV) ions and tin (II) ions in the treated plating composition were similarly evaluated. The concentration of tin (IV) ions was 0.20 mol / L, and the concentration of tin (II) ions was 0.0 mol / L. Based on this result, the reduction efficiency of tin (IV) ions was evaluated to be 0%.

[0079] The disclosure of Japanese Patent Application No. 2022-189216 (filing date: November 28, 2022) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard were specifically and individually described as being incorporated by reference.

Claims

1. A method for regenerating a plating composition, comprising: removing at least a portion of the surfactant from a plating composition comprising tin (IV) ions and the surfactant; A step of introducing the plating composition from which at least a portion of the surfactant has been removed into a working electrode chamber having a working electrode and separated from a counter electrode chamber having a counter electrode by one membrane selected from an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane, and reducing at least a portion of the tin (IV) ions in the introduced plating composition to metallic tin using the working electrode as a cathode; and A step of using the working electrode as an anode to oxidize at least a portion of the reduced metallic tin into tin (II) ions.

2. The regeneration method according to claim 1, wherein: At least a portion of the tin(IV) ions form a tin(IV) gluconate complex.

3. The regeneration method according to claim 1 or 2, wherein: The ion exchange membrane is a cation exchange membrane.

4. The regeneration method according to any one of claims 1 to 3, wherein The pH of the working electrode chamber is 1-13.

5. The regeneration method according to any one of claims 1 to 4, wherein An aqueous solution containing conductive ions is placed in the counter electrode chamber.

6. The regeneration method according to any one of claims 1 to 5, wherein The step of removing at least a portion of the surfactant from the plating composition includes contacting the plating composition with activated carbon.

7. The regeneration method according to any one of claims 1 to 6, wherein The surfactant includes at least one selected from the group consisting of a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant.

8. The regeneration method according to any one of claims 1 to 7, wherein The plating composition includes an antioxidant.

9. A regeneration device for a plating composition, comprising: a surfactant removal mechanism, a working electrode chamber having a working electrode, a counter electrode chamber having a counter electrode, and a membrane selected from an ion exchange membrane, a reverse osmosis membrane and a nanofiltration membrane for isolating the working electrode chamber from the counter electrode chamber.