JPS5920392B2 - Method for manufacturing colored copper coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a colored copper coating with good workability and excellent metallic luster.

Conventionally, copper and copper alloys have been widely used in furniture, ornaments, accessories, etc., and various methods of coloring them have been attempted.

For example, it is well known that the patina that naturally occurs on the surface of copper alloys gives products a complex aesthetic appearance.
A reddish-brown product is also obtained. However, all of these types of methods have drawbacks such as the color tone that can be obtained is limited because the color change is caused by the discoloration of the copper metal itself, it is difficult to control the color tone, and the processing time is long. Therefore, a method of forming a new colored coating film on the copper surface has been implemented, but this method not only does not take advantage of the copper luster of the product, but also gives the appearance that the colored layer is loose, and the deep coloring is not possible. We were unable to obtain a valuable product.

The present invention eliminates these drawbacks and provides a method for forming colored copper coatings with a greater variety than ever before with good reproducibility.

That is, the present invention is characterized in that a colored copper film is formed by applying a paint that combines copper powder and a colored pigment to the surface of a substrate.

Any solid substance that is stable at room temperature can be used as the base material, but specific examples include iron and other metals, plastics, glass, ceramics, paper, wood, leather,
Includes textile products, stone, cement, mortar, slate, rubber, etc.

Paints that incorporate copper powder and colored pigments may be applied directly onto such substrates, but in order to increase adhesive strength and obtain a uniform appearance, paints such as those later exemplified as color vehicles such as copper powder may be applied. It is more preferable to use it as an undercoat layer. Although the purity and particle size of the copper powder are not particularly limited, it is necessary that the copper powder be in a powder form that can be mixed uniformly with the coloring pigment.

As the coloring pigment, both ordinary pigments, inorganic pigments, and organic pigments can be used, but when treating with a sulfur-containing liquid after film formation, it is important to choose a pigment that will not be attacked by the treatment liquid.

Color vehicles for copper powder and coloring pigments include acrylic synthetic resin paints, polyurethane synthetic resin paints, epoxy synthetic resin paints, vinyl synthetic resin paints, phthalic acid synthetic resin paints, and melamine synthetic resin paints. , phenolic synthetic resin paint, alkyd synthetic resin paint, polyester synthetic resin paint, aminoalkyd synthetic resin paint, nitrocellulose synthetic resin paint, natural resin paint, etc.
Any of the conventional paint components can be used, selected depending on the process and purpose of the product.

It goes without saying that the above paint may contain additives other than copper powder and color pigments, such as pearl powder and various non-copper metal powders.

The paint used in the present invention, which has such a composition, is applied to the substrate with or without an undercoat layer, but in general, even if a uniformly mixed paint is used, the amount of pigment is lower than that of copper powder. A film is formed with some migration to the surface, so after the film has hardened, the surface of the film is polished using a metal brush, steel wool, various hubs, wrapping compound, cloth, etc. to remove the resin on the surface of the film. This makes it possible to obtain a colored copper film in which the color and luster of the copper metal are effectively harmonized with the color of the pigment, even with the addition of a small amount of pigment.

Furthermore, the effect of coloring can be enhanced by treating the film with a sulfur-containing liquid after forming the film to attack the copper on the surface and polishing it.

Here, the sulfur-containing liquid means a liquid containing active sulfur that can react with the copper powder exposed in the form of a foil on the surface by polishing.

For example, an aqueous sulfur suspension, an aqueous solution of sulfur dissolved in an alkali such as potassium sulfide, caustic soda, caustic potash, or quicklime, or a solution of sulfur in an organic solvent such as alcohol can be used.
However, in the case of a dispersion, the coloring may be spotty, so care must be taken depending on the purpose. This treatment with a sulfur-containing liquid is not intended to discolor the copper itself, but rather to attack the copper powder exposed on the surface of the film, suppressing its metallic luster and making the color of the surrounding coloring pigments appear more strongly. Therefore, sufficient effects can be obtained in a short treatment time of several minutes to several tens of minutes using a solution with a low sulfur content, which was previously unimaginable. The present invention achieves an unprecedentedly high-class image in a short time by using a simple coating process such as spraying, brushing, etc., immersion in a sulfur-containing bath as necessary, and polishing. A variety of colored copper coatings can be formed.

Examples [1] Using a horse-shaped iron casting as a base material, (1) first remove rust and oil from the surface of the casting, (2) then apply methacrylic resin paint twice by spray coating, Form an undercoat layer. ``1P? Toichi f-
D-11J-VIV No. 7 paint was diluted appropriately with thinner and coated 3 times with a brush, approx.
A film of 00μ was obtained.

(4) After being left to stand for 5 to 24 hours to harden, the surface was lightly polished with steel wool.

A shiny copper surface with a light blackish brown color was obtained. (5
) Next, 610HAP is heated and dissolved, the specific gravity at room temperature is concentrated to 30 degrees porta, and filtered.
% diluted solution for about 1 minute.

The color of the pigment was strongly visible on the copper surface, and it turned blackish brown. (6
) To obtain a stable and uniform film, the surface of the film was strongly brushed to remove the dark brown film, and then washed with water (
7) Step (5) was repeated again.

(8) The copper surface was then polished and polished with a cloth, resulting in a deep dark brown copper surface with excellent copper luster, and a dignified horse figurine was obtained.

Other finishing treatments include polishing the surface partially, polishing the surface, and further treating the selected film surface with a 0.1% diluted solution of treatment solution A, and coloring it by washing with water and post-processing. It was also possible to create a product with varying shading.

Example [2] A bronze-finished product was obtained by carrying out the same process as in Example [1] except that the paint consisting of 5) was used in the step (3) above.

A paint consisting of 11-5 widths is used in step (3), and treated for 5 minutes using a 0.1% diluted treatment solution A in steps (5) and (7). The same treatment as in Example [1] was carried out except for this.

The product had a beautiful shiny brass color. Example except that a paint consisting of was used in the step (3) above [
1].

A product having a red copper color and an elegant appearance was obtained.

The most common examples have been listed above, but all products before sulfur treatment were lightly colored. Results similar to those in the above examples were obtained when a 1% aqueous solution of potassium sulfide and a 0.5% sulfur-containing aqueous solution using sodium hydroxide as the alkaline component were used as the sulfur treatment. Furthermore, when an ethanol solution (saturated solution) containing a trace amount of sulfur was used, the reaction was weak and the effect was poor, but a product with a stronger degree of coloring than before treatment was still obtained. In each case, the degree of coloring of the reverse film surface could be varied by changing the sulfur content concentration of the treatment bath and the treatment time. Furthermore, if the colored copper film obtained in the present invention is further waxed or varnished, a product with better film protection and gloss can be obtained.

Claims (1)

[Claims] 1. A coating containing both copper powder and a colored pigment that is not attacked by a sulfur-containing liquid is applied onto the base material to form a film, and then the surface of the film is polished to remove the resin content on the surface. A method for forming a colored copper film, which comprises treating the surface of the film with a sulfur-containing liquid to attack the copper on the surface of the film, thereby suppressing its metallic luster and strongly revealing the color of the colored pigment.