WO2010055917A1

WO2010055917A1 - Acidic zinc plating bath

Info

Publication number: WO2010055917A1
Application number: PCT/JP2009/069372
Authority: WO
Inventors: 和生伊藤; 司榊原
Original assignee: ユケン工業株式会社
Priority date: 2008-11-14
Filing date: 2009-11-13
Publication date: 2010-05-20
Also published as: JP5272275B2; EP2357269A1; JPWO2010055917A1

Abstract

An acidic zinc plating bath having improved long-term stability even at high temperatures of 30-50°C. The acidic zinc plating bath contains a conductive salt, zinc metal and a brightening agent, and at least one kind of cumylphenol anionic surfactant is contained as a component of the brightening agent.

Description

Acid galvanizing bath

The present invention relates to an acidic zinc plating bath for electrogalvanization suitable for, for example, bright zinc plating of metal parts.

For various metal parts such as various processed products and molded products such as pins, bolts and nuts, it is widely practiced to improve corrosion resistance and appearance beauty by galvanizing.

Zinc plating includes hot dip galvanization and electro galvanization, but a plating bath is used for plating various metal parts by electro galvanization. In this case, a cyan bath and a zincate bath are used as the alkaline bath, and a sulfuric acid bath and a chloride bath are used as the acidic bath (see, for example, Patent Documents 1 to 5).

Acid baths are often used as plating baths for industrial products such as bolts and nuts because they have good current efficiency and are suitable for mass processing. Chlorine baths are widely used because they have features such as high productivity and easy plating on castings. The chloride bath includes an ammonium bath, a potassium bath, and an eclectic bath using both. However, recently, ammonium baths are becoming difficult to use due to stricter regulations on drainage of nitrogen and potassium baths due to regulations on drainage of boron of boric acid used as a buffering agent. The potassium bath does not use ammonium at all, but is inferior in productivity because abnormal precipitation called scorching occurs in a high current portion as compared with an ammonium bath or an eclectic bath. For this reason, eclectic baths are popular.

In bright zinc plating using an acidic plating bath, the addition of an organic compound called a brightener is indispensable for imparting luster to the plating. Conventionally, a naphthol anionic surfactant has been used as a brightener component (see, for example, Patent Document 6).

Conventionally, an acidic bath is often used at a low temperature of about 20 to 25 ° C. because the temperature rises when an electric current is passed, and becomes cloudy and loses its gloss due to the influence of the surfactant. For this reason, it is necessary to cool down, which is a cause of cost increase. On the other hand, plating at a high temperature may have good current efficiency, and in recent years, it has been increasingly used at a high temperature of 30 to 50 ° C.

JP-A-08-283984 JP-A-11-158683 JP 2002-004080 A JP 2004-339596 A JP 2006-322069 A JP 56-102589 A

However, the conventional high-temperature acidic zinc plating bath has poor bath stability. There was a change in pH and the occurrence of turbid precipitation when used at a high temperature of about 30 to 50 ° C. That is, in order to use at a high temperature of 30 to 50 ° C., it is necessary to prevent turbidity due to the influence of the surfactant of the brightener. In addition, generation and precipitation of decomposition products were also observed in the plating solution.

Furthermore, when the plating process was continuously performed, the cloud point was confirmed to be lowered by a constant energization. That is, it is difficult to maintain the plating performance as an initial high-temperature bath, and the aging stability of the plating bath has been a problem. Therefore, by increasing the amount of anionic surfactant added, the cloud point can be increased and the dissolution and dispersibility of the plating bath can be improved. However, if the amount added is excessive, it is a factor that lowers the plating performance. It was.

An object of the present invention is to provide an acidic zinc plating bath with improved temporal stability even at a high temperature of 30 to 50 ° C.

The present inventors have found that the above-mentioned problems can be solved by using a cumylphenol type anionic surfactant used as a brightener. That is, according to the present invention, the following acidic zinc plating bath is provided.

[1] An acidic zinc plating bath containing a conductive salt, metallic zinc, and a brightener, and containing at least one cumylphenol anionic surfactant as a component of the brightener.

[2] The acidic galvanizing bath according to the above [1], which contains zinc chloride as an acidic bath composition and further includes at least one selected from the group consisting of ammonium chloride, potassium chloride, and sodium chloride.

[3] The acidic galvanizing bath according to [1] or [2], wherein the cumylphenol anionic surfactant is a sulfate ester alkylene oxide adduct.

[4] The acidic galvanizing bath according to [3], wherein the sulfate ester alkylene oxide adduct is added with 1 to 30 moles of ethylene oxide as an alkylene oxide.

[5] The acidic galvanizing bath according to [3], wherein the sulfate ester alkylene oxide adduct is polyoxyethylene paracumyl phenyl ether sulfate ester salt.

ク Cumylphenol anionic surfactant has good dispersibility and has the effect of increasing the cloud point. The cloud point of the plating solution is stabilized during use, and the plating solution does not become cloudy or precipitate. That is, the stability over time during use of the bath is improved. Further, by using a cumylphenol anionic surfactant as the brightening agent, it is possible to maintain the plating luster during use (room temperature to 70 ° C.). Conventionally, the bath can be stably used even at high temperatures where the stability of the bath is poor.

It is a schematic diagram showing the results of a hull cell test of Example 1 of the eclectic bath (NH 4 _Cl-K). FIG. 6 is a schematic diagram showing the result of a Hull cell test of Comparative Example 4 of a β-naphthol eclectic bath (NH ₄ Cl—K). FIG. 6 is a schematic diagram showing the results of a hull cell test of a β-naphthol eclectic bath (NH ₄ Cl—K). FIG. 6 is a schematic diagram showing the results of a hull cell test of a β-naphthol eclectic bath (NH ₄ Cl—Na). It is a schematic diagram which shows the result of the Hull cell test of a potassium chloride bath and a sodium chloride bath. It is a schematic diagram which shows the result of the Hull cell test of a potassium chloride bath and a sodium chloride bath containing boric acid. It is a schematic diagram which shows the result of the hull cell test of an ammonium chloride bath.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

The acidic galvanizing bath of the present invention contains a conductive salt, metallic zinc, and a brightener, and contains at least one or more cumylphenol anionic surfactants as components of the brightener. The cumylphenol anionic surfactant is preferably a sulfate ester alkylene oxide adduct, and an alkylene oxide having 1 to 30 mol of ethylene oxide added is particularly preferable. Below, the example of a polyoxyethylene paracumyl phenyl ether sulfate ester salt is shown as an example of a cumylphenol sulfate ester alkylene oxide adduct (the following general formula (1)).

Here, EO represents ethylene oxide, n is the number of EO added moles, preferably 1 to 30, more preferably 5 to 15, and most preferably 7. The acidic zinc plating bath preferably contains 1 to 3 g / L, more preferably 2 g / L. Moreover, as a sulfate ester salt, although potassium salt is preferable, sodium salt and amine salt are also mentioned.

By selecting cumylphenol as an anionic surfactant and adding it to the acidic zinc plating bath, the clouding point of the plating solution will stabilize during use, and the effect of preventing the plating solution from becoming turbid or precipitated will be obtained. However, anionic surfactants other than cumylphenol may be included. For example, effects such as an increase in cloud point can also be obtained by adding a cumylphenol anionic surfactant to a bath containing a β-naphthol anionic surfactant. In other words, not only replacing the conventional addition of β-naphthol-based anionic surfactant in a zinc chloride plating bath with addition of cumylphenol-based anionic surfactant, but also when used in combination, effects can be obtained. When cumylphenol anionic surfactant is added, the cloud point is increased, the glossy surface of the plating (Hull Cell) is spread, and the plating bath is stabilized.

Use base brightener and brightener as brightener. The base brightener includes an anionic surfactant (containing 10 to 15% by mass), a nonionic surfactant, an aromatic carboxylate, and an organic amine salt. Brightener contains an anionic surfactant (containing 10 to 15% by mass), a nonionic surfactant, an aromatic carboxylate, an organic amine salt, and an aromatic aldehyde. The plating bath includes an anionic surfactant (1-5 g / L), a nonionic surfactant (1-5 g / L), an organic amine (0.5-5 g / L), an aromatic carboxylate (1 Base brightener and brightener are supplied as brighteners so that they are aromatic aldehydes (0.01-0.1 g / L).

As an anionic surfactant for base brighteners and brighteners, the above cumylphenol sulfate ester alkylene oxide adducts are included to assist the aromatic aldehydes that brighten brighteners and increase gloss. be able to. The cumylphenol sulfate ester alkylene oxide adduct has little performance degradation due to energization of plating and has aging resistance. And it can raise a cloud point and can improve turbidity and precipitation of a plating solution.

A high cloud point means that the surfactant is highly dispersible and suitable for high-temperature use. However, when using a Zn plating bath, an electrolyzed product is generated when plating is used, and the cloud point is high. It is better to set. Among the brightener components of acidic Zn plating used at high temperatures (30 to 70 ° C.), the function of an anionic surfactant is an important factor. The cumylphenol anionic surfactant has a high ability to dissolve and disperse other components, and raises the cloud point.

”Addition of an anionic surfactant increases gloss, and increasing the amount of anionic surfactant increases the cloud point. The cloud point cannot be maintained with a small amount of the anionic surfactant. On the other hand, if the amount is increased too much, the circulatory performance with plating, the appearance of the plating, the occurrence of spots, foaming and the like will occur, and the plating performance will deteriorate. The addition amount is preferably 1 to 5 g / L with respect to the plating appearance.

By including a nonionic surfactant, it is possible to improve throwing power and low electric partial gloss. Examples of nonionic surfactants include polyoxyethylene oxide.

By including an aromatic carboxylate, the low electric partial gloss can be improved. Aromatic carboxylates include benzoate, salicylate, cinnamic acid, m. P-chlorobenzoic acid, soluble salts thereof and the like can be mentioned.

High organic part kogation suppression can be improved by including an organic amine salt. Examples of the organic amine salt include polyethyleneimine, modified polyethyleneimine, and polyalkylenepolyamine.

Glossiness can be improved by including an aromatic aldehyde. Examples of the aromatic aldehyde include benzaldehyde and benzylideneacetone.

The acidic galvanizing bath of the present invention is an acidic electrogalvanizing bath and various acidic baths containing a conductive salt. That is, stability over time can be improved by including a cumylphenol anionic surfactant in various acidic baths. Furthermore, as the acidic zinc plating bath, a chloride bath containing zinc chloride is preferable, and examples of the chloride bath include an ammonium chloride bath, a potassium chloride bath, a sodium chloride bath, and an eclectic bath thereof. Is possible. That is, it is applicable to a chloride bath containing at least one of ammonium chloride, potassium chloride, and sodium chloride. An eclectic bath containing zinc chloride, ammonium chloride and potassium chloride is particularly preferred. As for sodium chloride baths, sodium salts have previously lowered the cloud point compared to potassium salts, and there were unstable factors over time, but by adding a cumylphenol anionic surfactant, Can be used stably. Acid zinc plating has the characteristics that it does not use cyan, has good current efficiency, has a high plating rate, and can be directly plated on castings and heat-treated products.

As the zinc ion supply source, one or more zinc salts selected from zinc chloride, zinc sulfate, zinc sulfite, zinc borofluoride, zinc sulfamate, zinc methanesulfonate and the like can be used. Zinc chloride is preferred as the source of zinc ions. Or it supplies by the electrolysis of the metal zinc of an electrode plate.

In addition to the above components, the acidic zinc plating bath of the present invention may further contain a small amount of components commonly used in plating solutions such as an antifoaming agent. The pH range of the plating solution is preferably 5 to 7, and more preferably 5.8 to 6.3. Therefore, the plating solution is acidic.

The composition of the acidic zinc plating bath of the present invention is not particularly limited, but a preferred plating solution composition is as follows.
Zinc chloride: 30-60 g / L (usage range: 10-120 g / L)
Ammonium chloride: 50 to 200 g / L (use range: 0 to 300 g / L)
Potassium chloride: 0 to 150 g / L (usage range 0 to 300 g / L)
Nonionic surfactant: 1 to 5 g / L
Polyethyleneimine: 0.5-5g / L
Benzylideneacetone: 0.01 to 0.1 g / L
Sodium benzoate: 1-5 g / L
pH: 5.8 to 6.3.

In the present invention, if the zinc chloride content is out of the above range, the predetermined bright zinc plating cannot be performed efficiently. Preferably, it is 30 to 60 g / L. When the content of ammonium chloride exceeds 300 g / L, the nitrogen concentration becomes high. Preferably, it is 50 to 150 g / L. Potassium chloride is contained to ensure the conductivity of the plating bath and reduce the nitrogen concentration. Preferably, potassium chloride is contained in an amount of 50 to 150 g / L. In order to ensure the conductivity of the plating bath, it is replenished with ammonium chloride or potassium chloride so that the amount of chloride ions is 120 to 180 g / L.

In addition, in the present invention, a surfactant such as a general nonionic surfactant may be appropriately blended. Each plating bath component constitutes an aqueous solution with a predetermined amount. For example, the pH is adjusted with hydrochloric acid, and the pH is usually adjusted to 5.8 to 6.3. The acidic zinc plating of the present invention may contain 1 to 50 g / L of boric acid.

In order to perform bright zinc plating of metal parts using the plating bath adjusted as described above, it may be performed in the same manner as in the conventional method, and is not particularly limited in the present invention. However, in the present invention, since the nitrogen concentration is reduced, the working environment is improved and the waste water treatment is simplified.

The current density can generally be used at an average of 0.3 to 5.0 A / dm ² , which is almost the same as that of a conventional zinc chloride plating bath, and the present invention is not inferior in terms of plating efficiency. . As described above, using a cumylphenol anionic surfactant as the brightener leads to stabilization of the plating solution over time when used at room temperature to 70 ° C.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

1-1. Eclectic bath (NH ₄ Cl-K)
A basic composition liquid A shown in Table 1 was prepared as a basic composition liquid for the plating solution. Basic composition liquid A was mixed with zinc chloride 40 g / L, potassium chloride 150 g / L, and ammonium chloride 50 g / L to a pH of 6.0.

Example 1
Next, what added the thing of Table 2 to the basic composition liquid A of Table 1 as an anionic surfactant was prepared. For example, as Example 1, 1 g of polyoxyethylene paracumyl phenyl ether sulfate of 7 mol of EO in potassium salt is added to 40 g / L of zinc chloride of basic composition liquid A, 150 g / L of potassium chloride and 50 g / L of ammonium chloride. / L mixed. Furthermore, a nonionic surfactant, an aromatic carboxylate 2 g / L, an organic amine salt 1 g / L, and an aromatic aldehyde 0.05 g / L were mixed. Similarly, 2 g / L of polyoxyethylene paracumyl phenyl ether sulfate ester salt of 7 mol of EO as a potassium salt was mixed to produce 3 g / L. The polyoxyethylene paracumyl phenyl ether sulfate potassium salt used is shown (the following general formula (1)).

(Examples 2 to 4)
For Examples 2 to 4, the compositions shown in Table 2 were prepared in the same manner as Example 1.

(Comparative Example 1)
As shown in Table 2, a basic composition solution A using a naphthol-based anionic surfactant was prepared. The comparative example 1 is specifically the following polyoxyethylene β-naphthyl ether sulfate potassium salt (m = 3, n = 12) (the following general formula (2)). Note that EO is ethylene oxide and PO is propylene oxide.

(Comparative Example 2)
As shown in Table 2, a basic composition solution A using a naphthol-based anionic surfactant was prepared. Comparative Example 2 is specifically the following polyoxyethylene β-naphthyl ether sulfate sodium salt (n = 12) (the following general formula (3)).

(Comparative Example 3)
As shown in Table 2, a basic composition solution A using a naphthol-based anionic surfactant was prepared. The comparative example 2 is specifically polyoxyethyleneoxypropylene naphthylsulfonic acid potassium salt (m = 3, n = 13) (the following general formula (4)).

(Comparative Examples 4 to 5)
As shown in Table 2, those using β-naphthol anionic surfactant were prepared. In Comparative Examples 4 and 5, Base Agent A (Comparative Example 4 is MZ-996A, Comparative Example 5 is ZB-627A) and Brightener GC are added as appropriate (addition amount is shown in Table 2). Liquid. The base agent A and the brightener agent GC include an anionic surfactant, a nonionic surfactant, an aromatic carboxylate, an organic amine, and an aromatic aldehyde.

(Cloud point)
The cloud point was measured as follows. First, 100 ml of the measurement solution (plating solution) was collected in a 100 ml heat-resistant glass beaker. Next, the measurement liquid was heated with an electric stove or the like and stirred so that the liquid temperature became uniform. Then, when a thermometer was set up at the center of a 100 mL beaker, the temperature at which the thermometer became cloudy and could not be seen was recorded.

As shown in Table 2, the cloud point of the example using the cumylphenol surfactant increased compared to the comparative example. In addition, although the cloud point of the comparative example 4 was 72 degreeC with a new liquid, since it fell by energization aging, it was not suitable for long-time use. “Recommended” and “Normal” in the table mean the most preferable. When the amount of the anionic surfactant is increased, the plating coverage decreases. Therefore, in the comparative example, “normal” is used as the most appropriate amount, and in the examples, “recommended” is the most appropriate amount.

For Example 1 and Comparative Example 4, the new solution and the aging solution were examined for cloud point, turbidity, and stability. The aging solution is a plating solution continuous energization process (120 AH / L). This corresponds to the amount of current applied per month for a general plating line.

As shown in Table 3, in Example 1, compared with Comparative Example 4, both the new solution and the aging solution had a higher cloud point and improved turbidity and stability. In addition, when there was no turbid precipitation and there was no change, it was considered good, and when slightly turbid precipitation was generated, it was considered slightly good.

(Hull cell test)
Moreover, in order to observe the bath state of a plating bath, the hull cell test was done. The Hull cell test was carried out for the new solution and aging solution of Example 1 and Comparative Example 4 by setting the bath temperature of the plating bath to 40 ° C. and energizing 1A for 10 minutes.

The results of Example 1 of the Hull Cell test are schematically shown in FIG. 1, and the results of Comparative Example 4 are schematically shown in FIG. As shown in FIG. 1, in Example 1, both the new solution and the aging solution were only slightly fogged in the low current part, but as shown in FIG. Clouding was observed over a wide area. Moreover, in Comparative Example 4, kogation was observed in the high electric part.

(Trivalent Cr chemical conversion treatment)
The trivalent Cr chemical conversion treatment was performed on the galvanized Example 1 and Comparative Example 4.
(1) YFA treatment:
Trivalent Cr chemical conversion treatment was performed using a trivalent Cr chemical conversion agent manufactured by Yuken Industry Co., Ltd. YFA-M: 100 ml / L and YFA-HR: 10 ml / L were used for 40 seconds in a plating bath at 40 ° C. and pH 2.0.
(2) YFB processing:
Trivalent Cr chemical conversion treatment was performed using a trivalent Cr black chemical conversion agent manufactured by Yuken Industry Co., Ltd. YFB-A3: 60 ml / L, YFB-B3: 100 ml / L, and YFB-C3: 60 ml / L were used for 60 seconds in a plating bath at 40 ° C. and pH 2.5. As finishing, CR-U: 200 ml / L, CR-I: 10 ml / L were used for 3 seconds in a 40 ° C. plating bath.

Appearance of the above-described YFA-treated and YFB-treated samples of Example 1 and Comparative Example 4 was confirmed by a Hull cell test (plating bath temperature 40 ° C., 1 A-10 minutes). In Example 1, whether the YFA treatment or YFB treatment was performed, the same good appearance as that of the comparative example 4 of the conventional product could be obtained.

1-2. Eclectic bath (including NH ₄ Cl-K, surfactants other than cumylphenol)
(Examples 5 to 6)
Polyoxyethylene paracumyl phenyl ether sulfate with potassium salt and 7 mol of EO as an anionic surfactant to the basic composition solution A plus a high-temperature plating bath (Metas MZ-996A / GC: made by Yuken Industry) The salt was mixed at 2 g / L (Example 5). In addition, a basic bath (METAS ZB-627A / G: manufactured by YUKEN INDUSTRY CO., LTD.) Is added to the basic composition liquid A, and as an anionic surfactant, 7 mol of polyoxyethylene paracumyl phenyl ether sulfate as a potassium salt and EO. The salt was mixed at 2 g / L (Example 6).

As shown in Table 2, the cloud point increased in Example 5 using cumylphenol surfactant compared to Comparative Example 4 and in Example 6 compared to Comparative Example 5. In other words, the cloud point increased by adding a cumylphenol surfactant to a β-naphthol eclectic bath (Ammon / Kali bath). FIG. 3 shows the result of the Hull cell test. As a result of the Hull Cell test, Example 5 to which a cumylphenol anionic surfactant was added had a glossy surface that was wider than that of Comparative Example 4, and that of Example 6 was better than Comparative Example 5. Obtained.

2-1. Eclectic bath (NH ₄ Cl-Na)
(Example 7)
Next, 1 to 3 g / L of a polyoxyethylene paracumyl phenyl ether sulfate salt of 7 mol of EO as a potassium salt, as shown in Table 4 as an anionic surfactant, in the basic composition liquid B of Table 1 Was made.

(Comparative Examples 6 to 8)
In addition, as a comparison, as shown in Table 4, the basic composition liquid B in Table 1 was used as an anionic surfactant, as shown in Table 4, polyoxyethylene naphthyl ether sulfate ester (Comparative Example 6), polyoxyethyleneoxypropylene naphthyl sulfate ester. A mixture of 1 to 3 g / L of a salt (Comparative Example 7) and polyoxyethyleneoxypropylene naphthyl sulfonate (Comparative Example 8) was prepared.

(Comparative Examples 9 to 10)
Further, as shown in Table 4, those using β-naphthol anionic surfactant were prepared. Comparative Examples 9 and 10 are based on Base A (Comparative Example 9 is MZ-996A, Comparative Example 10 is ZB-627A) and Brightener Agent (Comparative Example 9 is GC and Comparative Example 10 is G). It added suitably to the composition liquid B (refer Table 4 for the addition amount).

In the bath containing sodium chloride, the cloud point is lowered due to the difference in solubility between K and Na, compared to the bath containing potassium chloride. However, as shown in Table 4, when the cumylphenol surfactant was added, the cloud point also increased in the eclectic bath of the Ammon sodium bath.

2-2. Eclectic bath (including NH ₄ Cl-Na, surfactants other than cumylphenol)
(Examples 8 to 9)
As shown in Table 4, the basic composition solution B added with a high-temperature plating bath (Metas MZ-996A / GC: manufactured by Yuken Kogyo Co., Ltd.) was used as an anionic surfactant as a potassium salt with 7 mol of EO. 2 g / L of ethylene paracumyl phenyl ether sulfate was mixed (Example 8). In addition, a basic bath (Metas ZB-627A / G: manufactured by YUKEN INDUSTRY CO., LTD.) Added to the basic composition liquid B, as an anionic surfactant, 7 mol of polyoxyethylene paracumyl phenyl ether sulfate as a potassium salt and EO The salt was mixed at 2 g / L (Example 9).

As shown in Table 4, in Examples 8 to 9 using the cumylphenol surfactant, the cloud point was higher than that of the comparative example. That is, the cloud point was raised by adding a cumylphenol surfactant to a β-naphthol eclectic bath (ammonium / sodium bath). FIG. 4 shows the result of the Hull cell test. In Comparative Examples 9 and 10 using the conventional brightener, the cloud point was low, and in Comparative Example 10, the burn width was wide in the high electric portion, but Examples 8 to 9 were equivalent to the Comparative Example. The above results were obtained.

3. Potassium chloride bath (Example 10, Comparative Example 11)
As shown in Table 5, potassium salt as an anionic surfactant was added to the basic composition liquid C to which a high-temperature compatible plating bath (METAS FZ-300M / GR: manufactured by Yuken Industry) was added. 2 g / L of EO 7 mol of polyoxyethylene paracumyl phenyl ether sulfate was mixed (Example 10).

Even in a potassium chloride bath, the cloud point increased by adding a cumylphenol surfactant. FIG. 5 shows the result of the Hull cell test. As a result of the Hull cell test, the glossy surface of Example 10 spread better than the comparative example, and good results were obtained.

4). Sodium chloride bath (Example 11, Comparative Example 12)
As shown in Table 5, potassium salt as an anionic surfactant was added to the basic composition liquid D to which a high-temperature plating bath (METAS FZ-300M / GR: manufactured by Yuken Industry) was added. 2 g / L of EO 7 mol of polyoxyethylene paracumyl phenyl ether sulfate was mixed (Example 11).

Even in a sodium chloride bath, the cloud point increased by adding a cumylphenol surfactant. As shown in FIG. 5, when the hull cell test was performed, the glossy surface of Example 11 was wider than that of the comparative example, and good results were obtained.

5). Potassium chloride bath (containing boric acid)
(Example 12, Comparative Example 13)
As shown in Table 5, potassium salt as an anionic surfactant was added to the basic composition liquid E added with a high-temperature plating bath (Metas ZB-612A / GR: manufactured by Yuken Industry). 2 g / L of EO 7 mol of polyoxyethylene paracumyl phenyl ether sulfate was mixed (Example 12). Example 12 and Comparative Example 13 contain boric acid.

Even in a potassium chloride bath containing boric acid, the cloud point increased by adding a cumylphenol surfactant. FIG. 6 shows the result of the Hull cell test. When the Hull cell test was performed, Example 12 gave the same results as the comparative example.

6). Sodium chloride bath (containing boric acid)
(Example 13, Comparative Example 14)
As shown in Table 5, potassium salt as an anionic surfactant was added to the basic composition solution F to which a high-temperature compatible plating bath (METAS ZB-612A / GR: manufactured by YUKEN INDUSTRIAL CO., LTD.) Was added. 2 g / L of EO 7 mol of polyoxyethylene paracumyl phenyl ether sulfate was mixed (Example 13). Example 13 and Comparative Example 14 contain boric acid.

Even in a sodium chloride bath containing boric acid, the cloud point increased by adding a cumylphenol surfactant. As shown in FIG. 6, when the hull cell test was performed, in Example 13, the same result as in the comparative example was obtained.

7-1. Ammonium chloride bath (Example 14, Comparative Examples 15 to 18)
As shown in Table 6, 1 to 3 g / L of polyoxyethylene paracumyl phenyl ether sulfate ester salt of 7 mol of EO as a potassium salt was mixed with the basic composition liquid G as an anionic surfactant (Example 14). The basic composition liquid G was mixed with 1 to 3 g / L of polyoxyethylene naphthyl ether sulfate as an anionic surfactant (Comparative Example 15). Further, Metas MZ-996A / GC (Comparative Example 16), Metas ZB-627A / G (Comparative Example 17), and a brightener component (Comparative Example 18) were mixed with the basic composition liquid G.

Even in an ammonium chloride bath, the cloud point increased by adding a cumylphenol surfactant.

7-2. Ammonium chloride bath (including surfactants other than cumylphenol)
(Examples 15 to 16)
As shown in Table 6, a basic composition solution G added with a high-temperature plating bath (Metas MZ-996A / GC: manufactured by YUKEN INDUSTRY CO., LTD.) Is used as an anionic surfactant as a potassium salt with 7 mol of EO polyoxy 2 g / L of ethylene paracumyl phenyl ether sulfate was mixed (Example 15). In addition, a basic bath (Metas ZB-627A / G: manufactured by Yuken Kogyo Co., Ltd.) is added to the basic composition liquid G, and as an anionic surfactant, 7 mol of polyoxyethylene paracumyl phenyl ether sulfate with potassium salt as EO The salt was mixed at 2 g / L (Example 16).

As shown in Table 6, in Examples 15 to 16 using the cumylphenol surfactant, the cloud point increased compared to the comparative example. FIG. 7 shows the result of the Hull cell test. As a result of the Hull Cell test, Examples 15 to 16 had a glossy surface that was wider than that of the Comparative Example, and good results were obtained.

The use of cumylphenol surfactants improved the dispersibility of the composition and the like compared to conventional products, leading to improved turbidity and precipitation of the plating solution. By adding a cumylphenol surfactant to a conventional product containing a surfactant such as β-naphthol, the turbidity and precipitation of the plating solution could be improved. The high temperature bath is usually used at 30 to 50 ° C. However, by using a cumylphenol surfactant, the cloud point increased, and the plating treatment could be performed well even in the high temperature bath. Further, the bright appearance was obtained by increasing the solubility of Brightener's brightener component. Even in the chemical conversion treatment appearance, the glossy appearance was maintained.

As described above, there was little change in brightener due to high-temperature treatment and plating energization treatment, and stable use was possible, and the stability of the plating bath, which was a problem with conventional products, was improved. That is, by using a cumylphenol-based surfactant, the acidic zinc plating bath can be maintained at a high cloud point, and performance can be maintained even with respect to energization aging.

The acidic galvanizing bath of the present invention can be used as an acidic bath for zinc plating such as bolts and nuts.

1: plated surface, 2: cloudy, 3: burnt, 4: intense burnt, 5: glossy surface, 6: liquid surface.

Claims

Containing a conductive salt, metallic zinc, and a brightener;
An acidic galvanizing bath containing at least one cumylphenol anionic surfactant as a component of the brightener.
The acidic galvanizing bath according to claim 1, comprising zinc chloride as the acidic bath composition, and further comprising at least one selected from the group consisting of ammonium chloride, potassium chloride, and sodium chloride.
The acidic galvanizing bath according to claim 1 or 2, wherein the cumylphenol anionic surfactant is a sulfate ester alkylene oxide adduct.
The acidic zinc plating bath according to claim 3, wherein the sulfate ester salt alkylene oxide adduct is added with 1 to 30 moles of ethylene oxide as an alkylene oxide.
The acidic zinc plating bath according to claim 3, wherein the sulfate ester alkylene oxide adduct is a polyoxyethylene paracumyl phenyl ether sulfate ester salt.