JPH09202990A - Copper plating liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper plating liquid which allows copper plating with a good adhesion property and excellent appearance, is safe and is easy to handle by specifying the content of copper ions, pH, the content of a complex compd. having a high chelate stability constant and the concn. of a conductive salt. SOLUTION: The pH of the copper plating liquid contg. 5 to 200g/l copper ions is specified to >=5. Further, the complex compd. having the chelate stability constant of >=2.0 with copper at the equal mole to the mole of the copper or above is incorporated into this plating liquid. One or more of sulfate, carbonate, nitrate, chloride, phosphate and alkali hydroxide are incorporated as the conductive salts at 1 to 200g/l into the plating liquid. The copper plating liquid capable of plating the surfaces of metals to which an acidic copper plating liquid is hardly adherable with copper at the good adhesion property without using deadly poisonous cyanide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper plating solution, in particular, a non-cyan copper plating solution, in which copper plating is performed on the surface of a metal such as zinc, aluminum or iron which is difficult to be adhered by an acidic copper plating solution. It relates to a bath for plating with good adhesion.

[0002]

2. Description of the Related Art Zinc, aluminum, iron, etc. are plated with copper, nickel, chromium, gold, etc. on their surfaces in order to improve their corrosion resistance. In order to apply copper plating to these metals, copper cyanide plating has been conventionally performed.

[0003]

However, the cyan copper plating is extremely poisonous, and it requires a great deal of expense and a long treatment time to treat the waste water.

In view of the above prior art, it is an object of the present invention to provide a copper plating solution capable of realizing copper plating having good adhesion and excellent appearance without using highly poisonous cyanide. To do.

[0005]

The present invention for solving the above-mentioned problems is characterized by containing copper ions in an amount of 5 to 200 g / l. Further, it is characterized in that the pH is 5 or more.
In addition, a complex compound having a chelate stability constant with copper of 2.0 or more is contained in an amount of equimolar or more with copper. Furthermore, as conductive salts, sulfates, carbonates, nitrates, chlorides,
It contains at least one of phosphate and alkali hydroxide, and the concentration of each conductive salt contained is 1 to 200
It is characterized by being set to g / l.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to the copper plating solution of the present invention containing a complexing agent for a copper salt in an amount of equimolar or more to copper and containing a conductive salt in an amount of 1 to 200 g / l, adhesion can be achieved without using cyan Copper plating with good properties and excellent appearance can be formed.

A copper plating solution consisting of a non-cyan copper salt, a complexing agent, and a conductive salt exhibits excellent adhesion to zinc, aluminum and iron materials, and also has a good luster, so it is most suitable as an undercoat for accessories. is there.

In the copper plating solution of the present invention, if the copper ion content is less than 5 g / l, the throwing power is poor and the adhesion is poor. When the copper ion content is 200 g / l or more, precipitation occurs when the complexing agent is added. When the pH is less than 5, the throwing power is poor and the adhesion is poor. If the complexing agent is less than equimolar to copper, precipitation will occur when the pH is raised. If the chelate stability constant is 2.0 or less, the liquid decomposes when electrolyzed.

When the conductive salt concentration is 1 g / l or less, the electrolysis voltage becomes high, copper is less likely to deposit, and the conductive salt concentration is 200
If it is more than g / l, the bath cost is high, and it is likely to precipitate due to the solubility. There is also a method of adding a large amount of complexing agent to serve as a conductive salt, but this also increases the bath cost.

[0010]

EXAMPLES The present invention will now be described in more detail with reference to Examples.

<Example 1> 10 g / l of copper sulfate, 50 g / l of sodium citrate, and 100 g / l of sodium sulfate were dissolved in water and adjusted to pH 7.0 with caustic soda. 5 mm on a 20 mm x 20 mm iron plate that has been pretreated by a conventional method
It was plated at 0 ° C. and 1 A / dm ² for 3 minutes. Further, bright copper sulfate plating was applied to 10 μm and bright nickel plating was applied to 5 μm.

The plated surface produced by the above treatment was glossy and there was no peeling of the plating even if it was bent at 90 °.

Example 2 50 g / l of copper nitrate, 150 g / l of potassium tartrate and 30 g / l of potassium nitrate were dissolved in water, and the pH was adjusted to 10 with caustic. 25 mm x
A 25 mm zinc plate was pretreated by a conventional method, the plating solution was heated to 40 ° C., and plated at ^{2 A} / dm ² for 5 minutes. Further, bright copper sulfate plating was applied to 15 μm, bright nickel plating was applied to 5 μm, and chromium plating was applied to 0.2 μm.

The plated surface produced by the above treatment was glossy and there was no peeling of the plating even if it was bent at 90 °.

Example 3 Copper sulfate 30 g / l, EDTA
(Ethylenediaminetetraacetic acid) ・ 2Na 100 g /
1 and 50 g / l of sodium carbonate were dissolved in water, and the pH was adjusted to 8.5 with caustic soda. After polishing the buckle for belt made of zinc die-cast, pretreatment is performed by the usual method,
Plating was performed for 3 minutes at 3 A / dm ^{2 in the} plating solution heated to 45 ° C. Further, bright copper sulfate plating was applied to 12 μm, bright nickel plating was applied to 10 μm, and gold was applied to 1 μm.

This belt buckle was subjected to an ammonia backing test for 24 hours, an artificial sweat test for 24 hours, and a flapping test for each two pieces, each showing no abnormality.

The test solutions used in these tests are as follows.

(1) The artificial sweat composition in the artificial sweat test is
Salt 9.9 g / l, urea 1.7 g / l, sodium sulfide 0.8 g / l, ammonia water 0.07 ml / l, lactic acid 1.1 ml / l, sucrose 0.2 g / l, and water to a total volume of 1 liter. To do.

(2) As a test solution in the ammonia back test, 45 ml of ammonia water and 85 ml of pure water are filled in a desiccator having an inner diameter of 210 mmφ.

[0020]

EFFECTS OF THE INVENTION According to the present invention, there is no difference in terms of adhesion and appearance with copper plating as a base plating using conventional copper cyanide, and there is no danger because no toxic cyanide is used. It is also easy and wastewater treatment becomes easy.

Claims (4)

[Claims] 1. A copper plating solution containing copper ions in an amount of 5 to 200 g / liter. 2. The copper plating solution according to claim 1, which has a pH of 5 or more. 3. The copper plating solution according to claim 1 or 2, wherein a complex compound having a chelate stability constant with copper of 2.0 or more is contained in an amount of equimolar or more with copper. 4. The conductive salt contains at least one of a sulfate, a carbonate, a nitrate, a chloride, a phosphate, and an alkali hydroxide, and the concentration of each conductive salt contained is 1 to 1. The copper plating solution according to claim 1, 2 or 3, wherein the amount is 200 g / liter.