Brightener for electroplating, electroplating bath containing the same, and method for electroplating articles with metal.

Abstract

To provide an additive that suppresses a decrease in the film thickness of a plating film in a low current density zone.SOLUTION: A brightener for electric plating according to the present invention contains at least one of the compounds represented by Formula (1) or tautomers thereof: Formula 1 (where, one of X and Y is O and the other is S, and R is a linear or branched alkyl group with 1 to 5 carbons).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a brightener for electroplating, an electroplating bath containing the same, and a method for electroplating an article with a metal. [Background Art]

[0002] Various additives are added to electroplating baths to obtain good plating films. For example, Patent Document 1 describes that a compound substituted with a mercapto group such as thiouracil improves the glazing effect of a brightener. Further, Patent Documents 2 to 4 describe benzimidazoles as brighteners or auxiliary brighteners. On the other hand, Patent Documents 1 to 4 do not specifically describe the use of an alkylthiouracil compound as an additive for an electroplating bath. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 51-144342 [Patent Document 2] Japanese Unexamined Patent Publication No. 2003-73882 [Patent Document 3] Japanese Unexamined Patent Publication No. 2004-68153 [Patent Document 4] Japanese Unexamined Patent Publication No. 2013-23693 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] Compounds such as thiouracil do not form a good glossy appearance in low current density areas, and the overall thickness of the plating film tends to be thin. Benzimidazoles form a good glossy appearance and achieve a certain overall thickness, but they cause a decrease in film thickness in low current density areas. Therefore, when the thickness of the plating film is important, it was necessary to use these additives at low concentrations or not use them at all, sacrificing the glossy appearance. Thus, the present invention aims to provide an additive that suppresses the decrease in plating film thickness in low current density areas. [Means for solving the problem]

[0005] The inventors of the present invention, after diligent research to solve the above problems, discovered that by using a specific alkylthiouracil compound as a brightener for electroplating, it is possible to form a good glossy appearance while ensuring a certain degree of film thickness of the plating film in low current density areas, and thus completed the present invention. That is, the present invention provides the brightener for electroplating shown below, an electroplating bath containing the same, and a method for electroplating an article with a metal. [1] Formula 1: [ka] (1) (In the formula, One of X and Y is O, and the other is S. R is a linear or branched alkyl group having 1 to 5 carbon atoms. A brightener for electroplating comprising at least one of the compounds or tautomers thereof. [2] X is O, Y is S, and / or The brightener according to [1] above, wherein R is a linear alkyl group having 1 to 3 carbon atoms. [3] The compound is [ka] and / or [ka] The brightener according to [2] above, comprising [4] The brightener according to any one of [1] to [3] above, for use in zinc plating or zinc alloy plating. [5] An electroplating bath comprising metal ions, and at least one member selected from the group consisting of a compound of formula 1:

Chemical

Chemical

[10] The method according to [9] above, wherein the metal comprises zinc.

Effects of the Invention

[0006] According to the present invention, by using the compound of Formula 1 above or a tautomer thereof as a brightener for electroplating, a good glossy appearance can be formed while ensuring the film thickness of the plating film in a low current density region to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] [Figure 1] Shows the plating appearance of a cathode plate. [Figure 2] Shows the measurement results of the plating film thickness of a cathode plate. MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, the present invention will be described in further detail. The present invention relates to a brightener for electroplating, which is used for imparting gloss to a film formed by electroplating, and particularly for assisting in imparting gloss to a plating film in a low current density region. The brightener for electroplating of the present invention is represented by Formula 1: Chemical Formula (1) (wherein, one of X and Y is O and the other is S, R is a linear or branched alkyl group having 1 to 5 carbon atoms) comprises at least one of the compound or a tautomer thereof. Said compound or a tautomer thereof may be a so-called alkylthiouracil compound or a derivative thereof, and commercially available compounds can be used without particular limitation as a component of the brightener.

[0009] In one embodiment, in said compound, X may be O and Y may be S. In addition, R may be a linear or branched alkyl group having 1 to 3 carbon atoms. More specifically, said compound is Chemical Formula and / or Chemical Formula It may include.

[0010] The electroplating in which the brightener for electroplating of the present invention is used is not particularly limited and can be used for various types of electroplating. For example, the brightener may be used for zinc plating or zinc alloy plating.

[0011] By using the electroplating brightener of the present invention, it is possible to form a good glossy appearance while ensuring a certain level of film thickness in low current density areas. There is debate about the factors that cause the film thickness to decrease with conventional brighteners, but it is possible that the brightener is adsorbed onto the metal deposited on the surface of the object to be plated, reducing current efficiency, or that the brightener is adsorbed onto the surface of the metal plate that serves as the source of the metal to be plated, reducing the amount of metal that can be dissolved, and that the supply of metal to the plating bath cannot keep up. Although not bound by any particular theory, it is thought that the compound of formula 1 or its tautomer has low adsorption to deposited metal and metal plates, and contributes to maintaining current efficiency and the amount of metal dissolved.

[0012] The electroplating brightener of the present invention may further contain any components commonly used in the art, as long as their purpose is not impaired, and may further contain additional brighteners as described below. For example, the additional brighteners may include base component-based brighteners and gloss component-based brighteners. When the compound of Formula 1 and its tautomers are used in combination with these additional brighteners, it is useful for forming a plating film with a finer texture and better gloss.

[0013] In another aspect, the present invention also relates to an electroplating bath, which comprises metal ions and Formula 1: [ka] (1) (In the formula, One of X and Y is O, and the other is S. R is a linear or branched alkyl group having 1 to 5 carbon atoms. It contains at least one of the compounds of formula 1 or its tautomers. Any embodiment of the compound of formula 1 or its tautomer is as described in the electroplating brightener of the present invention. By using the electroplating bath of the present invention, a good glossy appearance can be formed while ensuring a certain thickness of the plating film in the low current density area due to the action of the compound of formula 1 or its tautomer.

[0014] The concentration of the compound of formula 1 or its tautomer in the electroplating bath of the present invention can be appropriately adjusted depending on the type of electroplating and the type of article to be electroplated, but for example it may be about 0.0007 to about 0.7 mmol / L, and preferably about 0.025 to about 0.1 mmol / L.

[0015] The metal ions mentioned above are not particularly limited as long as they are used in electroplating, but may include, for example, zinc ions, nickel ions, iron ions, copper ions, cobalt ions, tin ions, and manganese ions. If the metal ions consist only of zinc ions, a zinc film is formed on the article to be electroplated, and if the metal ions include zinc ions and other metal ions, a zinc alloy film is formed on the article. The other metal ions are not particularly limited as long as they can form the zinc alloy film, but may include, for example, at least one selected from the group consisting of nickel ions, iron ions, cobalt ions, tin ions, and manganese ions. The zinc alloy film is not particularly limited, but may include, for example, zinc-nickel alloy plating, zinc-iron alloy plating, zinc-cobalt alloy plating, zinc-manganese alloy plating, or tin-zinc alloy plating.

[0016] The ion source for the metal ions is not particularly limited as long as it is used in electroplating, but for example, ion sources that provide zinc ions include Na2[Zn(OH)4], K2[Zn(OH)4], or ZnO. The ion source for the metal ions may be used alone or in combination of two or more. The concentration of the metal ions in the electroplating bath is not particularly limited, but for example it may be about 2 to about 20 g / L, and preferably about 6 to about 16 g / L.

[0017] In some embodiments, the electroplating bath of the present invention may contain a caustic alkali. The caustic alkali is not particularly limited, but may be, for example, sodium hydroxide or potassium hydroxide. More specifically, if the electroplating bath is alkaline, sodium hydroxide may be included, and if the electroplating bath is acidic, potassium hydroxide may be included. The concentration of the caustic alkali when the electroplating bath is alkaline is not particularly limited, but may be, for example, about 60 to about 200 g / L, and preferably about 100 to about 160 g / L.

[0018] The pH of the electroplating bath of the present invention is not particularly limited as long as electroplating can be performed, but it may be, for example, about 8 or higher, that is, the electroplating bath may be alkaline. The pH of the electroplating bath can be adjusted using pH adjusting agents commonly used in the art as appropriate.

[0019] In some embodiments, the electroplating bath of the present invention may further include additional organic compound additives. As used herein, “organic compound additive” means an organic compound added to the plating bath for electroplating. The type of the additional organic compound additive is not particularly limited, but for example, when zinc plating is performed, the additional organic compound additive may be at least one selected from the group consisting of additional brighteners (brighteners other than the compounds of formula 1 and their tautomutants), water conditioners, and defoamers, and when zinc alloy plating is performed, the additional organic compound additive may be at least one selected from the group consisting of additional brighteners (brighteners other than the compounds of formula 1 and their tautomutants), metal complexing agents, water conditioners, and defoamers.

[0020] The additional brighteners can be those commonly used in the art without particular limitation, but examples include base component brighteners that mainly contribute to the coverage and uniform electrodeposition of the plating film, gloss component brighteners that mainly directly contribute to the glossing of the plating film, and auxiliary component brighteners that mainly assist in the glossing of the plating film in low current density areas. In some embodiments, the additional brighteners include base component brighteners and gloss component brighteners. When the compounds of Formula 1 and their tautomers are used in combination with these additional brighteners, it is useful for forming a plating film with a finer texture and better gloss.

[0021] The aforementioned base component-based glossing agent is not particularly limited, but examples include: (1) nonionic surfactants such as polyoxyethylene polyoxypropylene block polymer and acetylene glycol EO adduct, anionic surfactants such as polyoxyethylene lauryl ether sulfate and alkyl diphenyl ether disulfonate; (2) polyallylamines such as copolymers of diallyldimethylammonium chloride and sulfur dioxide; polyepoxypolyamines such as condensation polymers of ethylenediamine and epichlorohydrin, condensation polymers of dimethylaminopropylamine and epichlorohydrin, condensation polymers of imidazole and epichlorohydrin, condensation polymers of imidazole derivatives such as 1-methylimidazole and 2-methylimidazole and epichlorohydrin, and condensation polymers of heterocyclic amines including triazine derivatives such as acetoganamine and benzoguanamine and epichlorohydrin; condensation polymers of 3-dimethylaminopropylurea and epichlorohydrin, and bis(N,N-dimethylaminopropyl)urea and epi Polyamide polyamines such as polyamine polyurea resins such as condensation polymers with chlorhydrin, water-soluble nylon resins such as condensation polymers of N,N-dimethylaminopropylamine, alkylenedicarboxylic acid, and epichlorohydrin; condensation polymers of diethylenetriamine, dimethylaminopropylamine, etc., with 2,2'-dichlorodiethyl ether, condensation polymers of dimethylaminopropylamine and 1,3-dichloropropane, and 1,4-dichloropropane. (3) Polyalkylene polyamines such as condensation polymers with chlorobutane and condensation polymers of N,N,N',N'-tetramethyl-1,3-diaminopropane and 1,3-dichloropropan-2-ol; and other polyamine compounds; (4) Condensation polymers of dimethylamine and dichloroethyl ether; (5) Aromatic carboxylic acids such as benzoic acid or its salts; (6) Quaternary ammonium salts without nitrogen-containing heterocyclic compounds such as cetyltrimethylammonium chloride; or may also contain nitrogen-containing heterocyclic quaternary ammonium salts.

[0022] The nitrogen-containing heterocyclic quaternary ammonium salts are, for example, nitrogen-containing heterocyclic quaternary ammonium salts having a carboxyl group and / or a hydroxyl group. The nitrogen-containing heterocycle of the nitrogen-containing heterocyclic quaternary ammonium salt is not particularly limited, but may be, for example, a pyridine ring, piperidine ring, imidazole ring, imidazoline ring, pyrrolidine ring, pyrazole ring, quinoline ring, or morpholine ring, and is preferably a pyridine ring. More preferably, the nitrogen-containing heterocyclic quaternary ammonium salt is a quaternary ammonium salt of nicotinic acid or a derivative thereof. In the nitrogen-containing heterocyclic quaternary ammonium salt compound, the carboxyl group and / or hydroxyl group may be directly bonded to the nitrogen-containing heterocycle, or they may be bonded via other substituents, such as a carboxymethyl group. In addition to the carboxyl group and hydroxyl group, the nitrogen-containing heterocyclic quaternary ammonium salt may have additional substituents, such as alkyl groups. Furthermore, in the nitrogen-containing heterocyclic quaternary ammonium salts, the N substituent forming the heterocyclic quaternary ammonium cation is not particularly limited as long as it does not hinder the brightening effect, and may be, for example, a substituted or unsubstituted alkyl group, aryl group, or alkoxy group. The counter anion forming the salt is not particularly limited, but may be a compound containing, for example, a halogen anion, oxy anion, borate anion, sulfonate anion, phosphate anion, or imid anion, and is preferably a halogen anion. Such quaternary ammonium salts are preferable because they contain both a quaternary ammonium cation and an oxy anion in the molecule, and therefore also exhibit anionic behavior.

[0023] Specifically, the nitrogen-containing heterocyclic quaternary ammonium salts include, for example, pyridinium, N-benzyl-3-carboxypyridinium chloride, N-phenethyl-4-carboxypyridinium chloride, N-butyl-3-carboxypyridinium bromide, N-chloromethyl-3-carboxypyridinium bromide, N-hexyl-6-hydroxy-3-carboxypyridinium chloride, N-hexyl-6-3-hydroxypropyl-3-carboxypyridinium chloride, N-2-hydroxyethyl-6-methoxy-3-carboxypyridinium chloride, N-methoxy-6-methyl-3-carboxypyridinium chloride, N- These may include propyl-2-methyl-6-phenyl-3-carboxypyridinium chloride, N-propyl-2-methyl-6-phenyl-3-carbocypyridinium chloride, N-benzyl-3-carbocymethylpyridinium chloride, 1-butyl-3-methyl-4-carboxyimidazololium bromide, 1-butyl-3-methyl-4-carboxymethylimidazololium bromide, 1-butyl-2-hydroxymethyl-3-methylimidazololium chloride, 1-butyl-1-methyl-3-methylcarboxypyrrolidinium chloride, or 1-butyl-1-methyl-4-methylcarboxypiperidinium chloride. The nitrogen-containing heterocyclic quaternary ammonium salts may be used individually or in combination of two or more.

[0024] The concentration of the base component brightener in the plating bath is not particularly limited, but for example, in the case of aromatic carboxylic acids, it may be about 1 to about 500 mg / L, preferably about 5 to about 100 mg / L, and in other cases, it may be about 0.01 to about 10 g / L, preferably 0.02 to 5 g / L.

[0025] The gloss component-based brightener is not particularly limited, but may include, for example, aromatic aldehydes such as veratrolaldehyde, vanillin, and anisaldehyde. The concentration of the gloss component-based brightener in the plating bath is not particularly limited, but may be, for example, about 1 to about 500 mg / L, and preferably about 5 to about 100 mg / L.

[0026] The auxiliary component brightener is not particularly limited, but may include thiouracil compounds other than the compound of formula 1 and its tautomutants, mercapto compounds such as 2-mercaptobenzimidazole, and organic acids. The concentration of the auxiliary component brightener in the plating bath is not particularly limited, but may be, for example, about 0.01 to about 50 g / L.

[0027] The water conditioner can be any one commonly used in the art without any particular limitations, but for example, it may be silicic acid. The concentration of the water conditioner in the plating bath is not particularly limited, but for example, it may be about 0.01 to about 50 g / L. The defoaming agent can be any one commonly used in the art without any particular limitations, but for example, it may be a surfactant. The concentration of the defoaming agent in the plating bath is not particularly limited, but for example, it may be about 0.01 to about 5 g / L.

[0028] The metal complexing agent can be any commonly used in the art without particular limitations, but may also be an amine-based chelating agent, for example. For example, the amine-based chelating agent may be an alkyleneamine compound such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine; an alkylene oxide adduct of the alkyleneamine, such as an ethylene oxide adduct or a propylene oxide adduct; or an amino acid such as ethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, ethylenediaminetetra-2-propanol, N-(2-aminoethyl)ethanolamine, or 2-hydroxyethylaminopropylamine. The metal complexing agent may also include: chol; alkanolamine compounds such as N-(2-hydroxyethyl)-N,N',N'-triethylethylenediamine, N,N'-di(2-hydroxyethyl)-N,N'-diethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxyethyl)propylenediamine, and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine; poly(alkyleneimines) obtained from ethyleneimine, 1,2-propyleneimine, etc.; poly(alkyleneamines) obtained from ethylenediamine, triethylenetetramine, etc.; and poly(amino alcohols). Preferably, the metal complexing agent includes at least one selected from the group consisting of alkyleneamine compounds, alkylene oxide adducts thereof, and alkanolamine compounds. The metal complexing agent may be used alone or in combination of two or more types. The concentration of the metal complexing agent in the plating bath is not particularly limited, but may be, for example, about 5 to about 200 g / L, and preferably about 30 to about 100 g / L.

[0029] In another aspect, the present invention also relates to a method for electroplating an article with a metal, wherein the method involves ions of the metal and formula 1: [ka] (1) (In the formula, One of X and Y is O, and the other is S. R is a linear or branched alkyl group having 1 to 5 carbon atoms. The process includes applying current to an electroplating bath containing at least one of the compounds or tautomers thereof, The electroplating bath comprises the article as the cathode and a conductive substrate as the anode. Any embodiment of the compound of formula 1 or its tautomer and any embodiment of the electroplating bath are as described in the electroplating brightener and electroplating bath of the present invention. According to the method of the present invention, a good glossy appearance can be formed while ensuring a certain degree of film thickness of the plating film in the low current density region due to the action of the compound of formula 1 or its tautomer.

[0030] The metal is not particularly limited as long as it is used for electroplating, but for example, the metal may include zinc, nickel, iron, copper, cobalt, tin, and manganese. If the metal is zinc only, a zinc film is formed on the article, and if the metal includes zinc and other metals, a zinc alloy film is formed on the article. The other metal is not particularly limited as long as it can form the zinc alloy film, but for example, it may be at least one selected from the group consisting of nickel, iron, cobalt, tin, and manganese. The zinc alloy film is not particularly limited, but for example, it may be zinc-nickel alloy plating, zinc-iron alloy plating, zinc-cobalt alloy plating, zinc-manganese alloy plating, or tin-zinc alloy plating.

[0031] The aforementioned article is the object to be plated, and any material commonly used in the art can be used without particular limitation. The article may be made of various metals such as iron, nickel, copper, zinc, and aluminum, or alloys thereof. There are also no particular limitations on its shape, and various shapes can be used, such as sheet metal such as steel plates and plated steel plates, or shaped products such as rectangular parallelepipeds, cylinders, cylindrical objects, and spherical objects. Specifically, examples of such shaped products include fastening parts such as bolts, nuts, and washers, pipe parts such as fuel pipes, cast iron parts such as brake calipers and common rails, as well as various other items such as connectors, plugs, housings, fittings, and seat belt anchors.

[0032] The conditions for the energizing process are not particularly limited as long as the metal plating film can be applied, but for example, the energizing may be performed at a temperature of about 15°C to about 45°C, preferably about 25°C to about 35°C, or at about 0.1 to 20 A / dm 2 Preferably 0.2 to 10 A / dm 2 The cathode current density may be used to conduct the current.

[0033] The method of the present invention may further include any steps commonly used in the art, as long as they do not impair its purpose. For example, the method of the present invention may further include a step of cleaning the article before the energizing step, or a step of cleaning the article after the energizing step.

[0034] The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples. [Examples]

[0035] [Test Example 1] A long cell for Hull cell testing (anodic plate: 65 x 65 x 0.5 mm, cathode plate: 65 x 200 x 0.5 mm) was filled with 500 mL of a plating solution having the composition described in Table 1 below, and a Hull cell test (Hull cell long type) was performed under the plating test conditions of 2A-20 minutes at 30°C.

[0036] [Table 1]

[0037] The cathode was removed after plating, its appearance was visually evaluated, and the plating thickness was measured at 1 cm intervals from the left edge (high current density side) of the cathode plate using an X-ray fluorescence analyzer. Photographs of the cathode's appearance and the measured plating thickness are shown in Figures 1 and 2, respectively. Table 2 shows the range of the non-glossy area of ​​the cathode plate (distance from the left edge) and the average film thickness in the area 16-19 cm from the left edge of the cathode plate (low current density area).

[0038] [Table 2]

[0039] In Comparative Example 1, which did not use the test compound, a film of sufficient thickness (Figure 2) was formed, but its appearance was low gloss and uneven, with a wide area of ​​non-glossy texture observed on the low current density side, and some areas exhibiting black stripes (Figure 1 and Table 2). When 6-methyl-2-thiouracil (Example 1) or 6-propyl-2-thiouracil (Example 2) was used as the test compound, a film with high gloss and a smooth appearance was formed over a wide area of ​​the cathode plate (Figure 1 and Table 2), and the overall film thickness, as well as the film thickness in the low current density area, was at the same level as Comparative Example 1 (Figure 2 and Table 2).

[0040] In contrast, when simple 2-thiouracil (Comparative Example 2) was used as the test compound, it was not possible to form a film of sufficient thickness, resulting in a film with an undesirable appearance. When 2-mercaptobenzimidazole (Comparative Example 3) was used as the test compound, the appearance of the formed film was good (Figure 1), but the overall film thickness, especially in the low current density areas, was low. When a compound having a phenyl group at the 6th position of 2-thiouracil (Comparative Example 4) or a compound having a methyl group at the 5th position of 2-thiouracil (Comparative Example 5) was used as the test compound, both the appearance and film thickness of the formed film were only about the same as that formed with simple 2-thiouracil (Comparative Example 2). Therefore, the effect of forming a film with good appearance and film thickness, especially in the low current density areas, is a unique and excellent effect of 6-alkyl-2-thiouracil.

[0041] [Test Example 2] A zinc plate (Halcell anode zinc plate, 64mm x 64mm, manufactured by Yamamoto Plating Tester Co., Ltd.) was placed in a test tank containing 500 mL of the plating solution used in Test Example 1. An iron plate (perforated metal, black scale material, 50mm x 70mm) was then placed on top of the zinc plate and left at 30°C to partially dissolve the zinc plate. 2-mercaptobenzimidazole (Test Group 1) or 6-methyl-2-thiouracil (Test Group 2) were used as the test compound. The zinc concentration in the plating solution was measured by titration analysis before the start of the test and every two hours thereafter. The results are shown in Table 3.

[0042] [Table 3]

[0043] When 6-methyl-2-thiouracil was added to the plating solution, the zinc dissolution rate was higher compared to when 2-mercaptobenzimidazole was added. Maintaining a good zinc dissolution rate is considered to be one of the factors that suppresses film thickness reduction with 6-alkyl-2-thiouracil.

[0044] From the above, it was found that by using the compound of Formula 1 or its tautomer as a brightener for electroplating, a good glossy appearance can be formed while ensuring a certain level of film thickness of the plated film in low current density areas.

Claims

1. Formula 1: 【Chemistry 1】 （１） (In the formula, If one of X and Y is O and the other is S, R is a linear or branched alkyl group having 1 to 5 carbon atoms. A brightener for electroplating of zinc or zinc alloy, comprising at least one compound or tautomer thereof.

2. X is O, Y is S, and / or, The brightener according to claim 1, wherein R is a linear alkyl group having 1 to 3 carbon atoms.

3. The aforementioned compound, 【Chemistry 2】 and / or 【Transformation 3】 The glossing agent according to claim 2, comprising:

4. Metal ions and Equation 1: 【Chemistry 4】 （１） (In the formula, If one of X and Y is O and the other is S, R is a linear or branched alkyl group having 1 to 5 carbon atoms. It comprises at least one of the compounds or tautomers thereof, An electroplating bath in which the aforementioned metal ions include zinc ions.

5. X is O, Y is S, and / or The electroplating bath according to claim 4, wherein R is a linear alkyl group having 1 to 3 carbon atoms.

6. The electroplating bath according to claim 4 or 5, which is alkaline and / or further comprises additional organic compound additives.

7. A method of electroplating an article with metal, The aforementioned metal ions and formula 1: 【Transformation 5】 （１） (In the formula, If one of X and Y is O and the other is S, R is a linear or branched alkyl group having 1 to 5 carbon atoms. The process includes applying current to an electroplating bath containing at least one of the compounds or tautomers thereof, The aforementioned metal includes zinc, A method wherein the electroplating bath comprises the article as the cathode and a conductive substrate as the anode.

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