JPS639596B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to an electroplating bath for forming a golden coating on a metal surface by electroplating. <Prior Art> Various plating methods have been developed to form golden coatings on various daily necessities and decorative items made of metal, thereby increasing their decorative value. For example, one of the most common methods is plating using a plating bath containing cyanide. A typical bath composition is cyanide soda 50g/~
150 g/, cuprous cyanide 30 g/~75 g/, zinc cyanide 11 g/~30 g/, and soda carbonate 20
g/~15g/ as a main component. This plating method using a cyanide-containing bath requires strict safety management because it uses a toxic cyanide, and in particular, the working temperature is as high as 50 to 65°C, so it does not contain cyanide, which is highly toxic. Generates gas and is not good for occupational health. The film that is formed is very different from actual gold in terms of color and luster.
The average color tone is a true color with a bluish tinge, but it also has drawbacks such as the color tone changing from whitish yellow to reddish yellow due to temperature differences, PH changes, changes in current density, etc. . The inventor of the present invention previously learned that a bath containing 1,1-hydroxyethane-1,1 secondary phosphate ester or a salt of the ester was used as an electroplating bath. No. 23151, he filed a patent application for this plating bath, disclosing that it was possible to safely obtain a golden coating that was better than conventional methods. <Problems to be Solved by the Invention> However, the gold-plated films obtained based on these methods are still insufficient in both color feel and tone compared to true gold-plated films. The dot was hot. As a result of further research, the present inventor found that by electroplating using a bath in which glycolic acid was present together with 1,1-hydroxyethane-1,1 secondary phosphates and/or organic amines, The present invention was completed after learning that a golden plating film with good color tone and luster could be obtained. <Means for solving the problems> That is, the present invention provides copper iacetate, copper chloride, copper tartrate,
At least one of copper citrate and copper sulfate
seeds, at least one of zinc roacetate, zinc chloride and zinc sulfate, haglycolic acid, di-1,1
- at least one of hydroxyethane 1,1-secondary phosphate, 1,1-hydroxyethane 1,1-secondary phosphate salt, and organic amine;
The present invention relates to a plating bath in which seeds are dissolved in water as a main component, and a plating bath in which at least one of a tin compound, an indium compound, a nickel compound, and a cobalt compound is further dissolved. <Example> Next, each substance to be dissolved when manufacturing the electroplating bath of the present invention will be described in detail. The substance for forming a golden film is a copper compound other than cyanide, specifically copper acetate, copper chloride, copper tartrate, copper citrate and copper sulfate, a zinc compound other than cyanide,
Specifically, zinc acetate, zinc chloride and zinc sulfate. As the tin compound, stannic sulfate, stannic chloride, sodium stannate, etc. are preferable, and as for the indium compound, nickel compound, and cobalt compound, chloride, sulfate, acetate, etc. are preferable. Each of these contributes to the formation of a golden film, but furthermore, the copper compound is compatible with a bath containing a chelating agent and has the effect of facilitating adjustment of the plating bath, and other film-forming substances Since both have high solubility, they can be easily dissolved to prepare a uniform plating bath composition. As described above, the coating forming substance in the plating bath of the present invention contains a copper compound and a zinc compound as essential components. Included in invention. A major feature of the present invention is that the bath composition contains at least one of glycolic acid, 1,1-hydroxyethane-1,1 diphosphoric acid ester, a salt of the same, and an organic amine. Although the addition of glycolic acid is essential, 1,1-
At least one of hydroxyethane-1,1 secondary phosphate ester, ester salt, and organic amine may be included. 1,1-hydroxyethane 1,1-secondary phosphate ester is It is a compound represented by , and the salt produced by the reaction of the same ester with an alkali metal or an alkaline earth metal can also be used in the same way as the ester. Also, examples of organic amines include ethylenediamine, propanediamine, and ethylenediaminetetraacetic acid4.
Sodium, disodium, etc. are preferred. Due to the presence of these, the coating obtained using the plating bath of the present invention is not inferior in color tone or gloss compared to a gold plating coating made using an actual gold compound. This is based on the following reasons. That is, the metal coexisting with the organic amine, the ester, and the ester salt forms a chelate compound, and the metal is smoothly removed from the chelate compound.Furthermore, due to the adsorption effect of the organic amine and the like on the base metal, the convex portions of the base plane, i.e. This is because the plated surface can be smoothed quickly by suppressing electrodeposition in areas where electricity is concentrated. Next, the amounts of each component to be dissolved in producing the 1000 c.c. plating bath of the present invention will be described. The copper compound as a film-forming component is used as metallic copper.
The amount of the zinc compound is 0.25 g to 1.3 g, preferably 0.5 g to 0.9 g as metal zinc. In the case of one type of tin compound, indium compound, nickel compound, and cobalt compound, the metal is 0.8 g to 1.2 g, preferably 0.5 g.
~1.0g, indium 0.2g~2.0g, preferably
0.3-1.5g, Nickel 0.5g-3.0g, preferably
0.7g to 2.0g, cobalt 0.5g to 3.5g, preferably 0.7g to 2.0g, and when a plurality of the above tin compounds, indium compounds, nickel compounds and cobalt compounds are present, a total of 1.0g to 4.5g.
g, preferably 1.2 g to 4.0 g. If the above amount is exceeded, grayish-white streaks or coarse electrodeposit will occur in areas of high current density, and if it is slightly excessive, copper electrodeposition will be accelerated and the entire plating film will become pinkish yellow. becomes. If the above amount is not reached, only copper will precipitate and the color will not turn yellow. The amount of the film-forming compound is determined depending on the desired color tone of the film to be formed. Generally, zinc emphasizes blue-white color, but in the present invention, when present in an appropriate amount, zinc emphasizes yellow, and when in excess, zinc emphasizes pink. Likewise, if tin is used in an appropriate amount, it will accentuate the yellow color, and if it is used in excess, it will emphasize the whitish yellow color. Indium behaves similarly to zinc, nickel, and cobalt to tin. Glycolic acid is 20g to 60g, preferably 15g to
It is 45g. If the upper limit is exceeded, a preferable alloy coating cannot be obtained, and only copper will precipitate. In addition, if the lower limit is not reached, various precipitates of the film-forming metal, for example, when the film-forming metal is copper, zinc, tin, zinc-copper, tin-copper, or tin-zinc-copper and various separated Collect the precipitate. 1,1-hydroxyethane-1,1 secondary phosphoric acid ester or its salt is 10g to 30g as ester
g, preferably 18g to 25g, organic amine 3g to
12 g, preferably 6 g to 10 g. Additionally, known additives used in ordinary plating baths, such as conductive agents such as sodium carbonate, can be added to the plating bath of the present invention, if necessary. Note that ammonia water cannot be used. The target metal to be plated using the electroplating bath of the present invention is exactly the same as the target metal for decorative plating currently practiced. Further, electroplating using the present invention can be performed by a known method. Next, examples of the present invention and comparative examples will be shown. Examples Table 1 shows the bath compositions used in the examples, Table 2 shows the plating conditions, and Table 3 shows the plating results.

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[Table] Comparative Examples As shown in Table 4, the composition of the film forming material in the plating bath was exactly the same as in each example, containing no glycolic acid and containing 1,1-hydroxyethane-2
Plating solutions were prepared with different phosphate ester contents and used for plating. Table 5 shows the plating results. It should be noted that the glazing conditions are the same for the examples and comparative examples with the same numbers.

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【table】

[Table] The criteria for judgment in Tables 3 and 5 are shown below. Judgments in the first column indicate that there are no defects when observed with the naked eye.
○ for beautiful items, △ for items with defects such as streaks.
Poor quality with no luster was marked as ×. The second column relates to the chromaticity of gold in the coating, which is the object of the present invention, and was determined using a color difference meter (manufactured by Chiyoda Kogaku). It is determined by three elements: chromaticity L, a, and b. Their relationship is shown in the drawing. L indicates the overall brightness; the closer the value is to 100, the whiter the color, and the closer the value is to 0, the closer the color is to black.
For the value of a, the larger the (+) value, the redder the color, and (-)
The larger the b value, the greener the color, the larger the (+) value of b, the more yellow the color, and the larger the (-) value, the bluer the color. For pure gold L: 70.2, a: 2.0, b: 36.8 For brass L: 69.5, a: -0.1, b: 28.9 From the above, L, a, and b are all between pure gold and brass. A, b is 28.0 or less or a is -0.1
The following were designated as B, and those with a of 2.5 or higher were designated as C. Then, from the above two determinations, a third column comprehensive determination was made. That is, those with no defects were rated as ○, those with good chromaticity but with defects such as streaks were rated as △, and those with poor visual observation and poor chromaticity were rated as ×. <Effects of the Invention> As is clear from Tables 3 and 5, when the plating bath of the present invention is used, the plating film produced is at first glance hardly different from gold, and has no practical value. It is extremely large.

[Brief explanation of the drawing]

The drawing shows the relationship between chromaticity L, a, and b.

Claims (1)

[Scope of Claims] 1. At least one of copper acetate, copper chloride, copper tartrate, copper citrate, and copper sulfate; (b) At least one of zinc acetate, zinc chloride, and zinc sulfate; (c) Glycolic acid; A golden color obtained by dissolving in water the main components of at least one of 1,1-hydroxyethane 1,1-secondary phosphate, 1,1-hydroxyethane 1,1-secondary phosphate, and organic amine. Electroplating bath for film formation. (2) At least one of copper acetate, copper chloride, copper tartrate, copper citrate, and copper sulfate; (b) At least one of zinc acetate, zinc chloride, and zinc sulfate; Tin compounds, indium compounds, nickel compounds, and cobalt compounds at least one of diglycolic acid, 1,1-hydroxyethane 1,1-secondary phosphate, 1,1-hydroxyethane 1,1-secondary phosphate salt, and at least one of organic amines. An electroplating bath for producing a golden film, which is dissolved in water as the main component.