JP2899353B2 - How to color zinc and zinc alloys - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for coloring a product made of zinc or a zinc alloy or a plated product of zinc or a zinc alloy by applying a metal substitution reaction with a manganese salt.

[Conventional technology] Zinc and zinc alloys are used for rust prevention of steel materials, facilities and parts in the construction industry, metal product manufacturing industry, electrical equipment manufacturing industry, transportation / electric power / communication / gas water industry, and others. And widely used as a zinc anode for cathodic protection.

In recent years, with the diversification of uses of steel products, zinc plating applied to the surfaces of bridges, steel towers, guardrails, lighting poles, interior and exterior materials of buildings, and other buildings has been rustproof. There has been a demand for a colored galvanized product that is in harmony with the surrounding environment and has an excellent aesthetic appearance, rather than the metallic color of zinc itself for the purpose of effect only.

The conventional method of coloring galvanized products is painting, and colored galvanized steel sheets by painting are well known.

[Problems to be Solved by the Invention] However, the paint coloring of the galvanized steel sheet is that the plating surface is smooth and the anchor effect of the coating film on the ground is small, and that zinc is a chemically active amphoteric metal. For this reason, the following is performed to improve the adhesion of the coating film.

First of all, galvanized products are chemically converted to deactivate zinc,
Next, a primer coat is applied to further inactivate zinc and enhance the anchor effect. In other words, the pretreatment process for painting is complicated and time-consuming.

Further, the above-mentioned painting and coloring method is not suitable for articles having a plurality of shapes, and the cost of a single article is high.

Furthermore, when a part of this painted product is peeled, the peeling proceeds in a chain from that part, and the expected sufficient effect may not be obtained.

The present invention achieves a uniform adhesion to products of complicated shapes by a simple operation of immersing a product made of zinc or zinc alloy or a zinc or zinc alloy plated product in a predetermined solution without a base treatment. It is an object of the present invention to provide a method capable of forming a colored film excellent in quality.

[Means for solving the problem]

The present invention has been made to achieve the above object.

That is, the present invention provides a manganese ion concentration of 0.005 to 2.5.
A method for coloring zinc and a zinc alloy, characterized by immersing a product made of zinc or a zinc alloy or a zinc or zinc alloy plated product in an aqueous solution containing mol / manganese salt.

In the present invention, hydrogen peroxide water can be present as an oxidizing agent in the aqueous solution of the manganese salt for the purpose of promoting a metal substitution reaction of the manganese salt.

The coloring method of the present invention is a hot-dip galvanized product, an electro-galvanized product, a product covered with zinc such as a zinc die-cast product or a hot-dip galvanized alloy product, an electro-zinc alloy plated product,
A product such as a zinc alloy die-cast product whose surface is covered with an alloy containing zinc as a main component can be used.

Manganese salts used in the coloring solution include manganese chloride, manganese sulfate, manganese nitrate and the like, and one or more of these can be used. The concentration of the manganese solution is 0.005 to manganese ion concentration.
A range of 2.5 mol / is desirable. The best results are obtained in the range of 0.2 to 1.5 mol /. When the manganese ion concentration is 0.005 mol / or less, it is insufficient to form a colored film on the surface of the zinc or the alloy containing zinc as a main component. When the manganese ion concentration exceeds 2.5 mol /, a portion insoluble in water remains. Not preferred.

A commercially available hydrogen peroxide solution to be added to the manganese salt aqueous solution can be used. The concentration of the hydrogen peroxide solution in the aqueous manganese salt solution in the present invention is preferably in the range of 0.02 to 40 mol /. When the concentration of the aqueous hydrogen peroxide is 0.02 mol / or less, there is no significant effect, and when it exceeds 40 mol /, the reaction becomes too violent, which is not preferable.

(Operation)

When a product made of zinc or a zinc alloy or a zinc or zinc alloy plated product is immersed in an aqueous solution of manganese salt at the above concentration, a substitution reaction between manganese and zinc occurs, and the color of the product becomes the metallic color of zinc itself (brightness). Some white)
From gold to brown, and to brown with the immersion time.

In the present invention, in the range of the concentration of the manganese ion, the higher the concentration, the shorter the color can be colored, and the higher the concentration of the hydrogen peroxide solution in the range, the shorter the color. .

The temperature of the aqueous solution when performing the coloring treatment is preferably from 10 to 50 ° C. At a liquid temperature of 10 ° C. or lower, the reaction does not proceed. At a liquid temperature of 50 ° C. or higher, the decomposition reaction of the hydrogen peroxide solution is severe and dangerous.

When the target color is obtained by the coloring process, the object is pulled up from the liquid, washed with water and dried.

As described above, a product made of zinc or a zinc alloy, or a zinc or zinc alloy plated product can be colored.

〔Example〕

 Next, the present invention will be described specifically with reference to examples.

Example 1 A mixed aqueous solution containing 1.0 mol / of manganese chloride (tetrahydrate) and 1.0 mol / of hydrogen peroxide solution was used as a coloring treatment liquid, and was subjected to hot dip galvanizing (aluminum content 0.1%).
Hereinafter, a steel sheet was immersed and colored at 20 ° C and 40 ° C. Table 1 shows the immersion time until the desired coloring.

Example 2 As a result of performing the coloring treatment in the same manner as in Example 1 except that a mixed aqueous solution of 0.5 mol / manganese sulfate (hydrate) and 1.0 mol / hydrogen peroxide solution was used as a coloring treatment liquid,
The immersion time shown in Table 1 was used.

Example 3 A coloring treatment was performed in the same manner as in Example 1 except that a mixed aqueous solution containing 0.5 mol / manganese nitrate (hydrate) and 1.0 mol / hydrogen peroxide solution was used as a coloring treatment liquid. Table 1 shows the immersion time until the desired coloring.

(Effect of the Invention) According to the coloring method of the present invention, even if the product made of zinc or zinc alloy, or the zinc or zinc alloy plated product has a complicated shape, the manganese ion concentration is 0.005 to 2.5.
Mol / manganese salt and aqueous hydrogen peroxide 0.02 to 40 mol /
It can be colored by a simple operation of merely immersing in an aqueous solution containing, and the cost is low because no undercoating treatment is required and the aqueous solution can be easily prepared. Further, a constant color tone (golden or brown) can be obtained by adjusting the concentration, temperature, processing time, and the like of the coloring liquid.

Then, a colored film having good adhesion is formed uniformly on the entire surface of the product, and the colored film has a thickness of about 5 μm containing zinc and manganese as main components, and has excellent weather resistance, particularly excellent ultraviolet light resistance. In addition, even if the colored film is partially peeled, the peeling does not proceed in a chain from that part, which is effective as a method for coloring zinc and a zinc alloy.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Oda 58 Koganecho, Yokkaichi-shi, Mie Uchida Forging Co., Ltd. (72) Inventor Yoshifumi Yasuda 58 Koganecho, Yokkaichi-shi, Mie Uchida Forging Co. References JP-A-57-181379 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23C 22/00-22/86

Claims (2)

(57) [Claims] 1. A manganese ion concentration of 0.005 to 2.5 mol /
Coloring of zinc and zinc alloys by immersing a product made of zinc or zinc alloy or a zinc or zinc alloy plating product in an aqueous solution containing a manganese salt of manganese and causing a substitution reaction between manganese and zinc Method. 2. A method for coloring zinc and a zinc alloy according to claim 1, wherein 0.02 to 40 mol / hydrogen peroxide is present in the aqueous solution of manganese salt.