JPS6126825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal coating agent applied onto the surface of a sculptural object.

Sculptures made of metal castings have been produced since ancient times, and over the years these objects have come to be admired and deeply admired by the public. In addition, many of these metal castings are made of copper, bronze, or iron, and as they age, these castings darken in color, develop green rust, or develop blackish brown rust, giving them an increasingly deep aesthetic sense. This increases the so-called antique value. However, the production of such cast sculptures requires considerable equipment, difficult processes, and a long experience, making it difficult and inaccessible for ordinary people to produce. However, if such sculptures could be easily imitated, children with a desire for crafts,
It is thought that even middle-aged and elderly people will be more motivated to create.

In this sense, the inventor filed the patent application No. 54-167590.
No. ``Title of the Invention: Treatment agent for metal coating surfaces'' was filed. According to the application, the surfaces of sculptures made of synthetic clay in various shapes are coated with a coating agent made by mixing copper powder with a polyacrylic acid ester emulsion (hereinafter referred to as polyacrylate) liquid for a long period of time. A darkened surface containing green rust was obtained in a short period of time by treating the left surface with a metal treatment agent containing a mixture of alkali sulfide, ammonium chloride, ammonium carbonate, and a water-soluble organic solvent. In this case, the processing agent of the application contains a water-soluble organic solvent in addition to the sulfurized alkali salt and the inorganic salt.

This means that when a conventional metal coating agent made of copper powder and polyacrylate emulsion is applied to the surface of a sculptural object, the darkening effect gradually becomes weaker when a treatment agent that does not contain the above water-soluble organic solvent is applied around 30 minutes after application. However, it has the disadvantage that it has to be post-treated in a short period of time because it has almost no effect after two hours.

This is because the surface of the polyacrylate resin on the coating surface gradually hardens and becomes fixed, so the processing agent to be treated next is repelled on the resin coating surface, making it difficult for it to come into contact with the copper powder surface in the coating. This is because darkening reactions are less likely to occur. For this reason, in the application, a water-soluble organic solvent is dissolved in the processing agent in order to prevent this. This is because the water-soluble organic solvent acts on the polyacrylate resin on the painted surface of the above-mentioned sculpture, causing it to swell, and as a result, the components in the treatment agent seep through and come into contact with the copper powder surface, reacting and darkening it. This is because it can be done.

However, organic solvents generally have many problems in storage, for example, there are restrictions on the containers in which they can be stored. For example, water-soluble ethanolamine easily corrodes polyacrylate capacitors, and the surface of the container is susceptible to wetness, so the price increases as the container is made to be special.

For the reasons described above, the present invention differs from the application in that a small amount of water-soluble polymer, such as polyvinyl alcohol (hereinafter referred to as POVAL) or methyl cellulose, is mixed with a mixture of copper powder and polyacrylate emulsion on the surface of the sculpture. It is a dissolved coating agent. That is, even if the metal coating agent based on the present invention is applied to the surface of a sculptural object for more than 2 hours, it can exhibit the same darkening and greening effect as if it were treated with a treatment agent immediately after application.

After several hours or more of application of the metal coating agent according to the present invention on the surface of the sculptural object as described above, a coating treatment agent that does not contain a water-soluble solvent, such as an alkaline sulfide water container or Sodium sulfide,
When the coating surface was treated with an aqueous solution containing a mixture of ammonium chloride and ammonium carbonate, the coating surface could be easily darkened and turned green. Next, embodiments of the metal coating agent based on the present invention will be described.

Most of the sculptural objects to be coated used in the present invention are made of synthetic clay, and the metal coating agent based on the present invention is applied onto the surface of these sculptural objects in various shapes. This metal coating agent is made by dissolving copper powder (100 to 250 mesh) in polyacrylate emulsion (solid content approximately 50%) and adding a water-soluble polymer such as poval or methyl cellulose in an amount of 0.1% or more of the emulsion liquid. It is a mixture of the following. However, in this case, when the water-soluble polymer CMC (carboxyl methyl cellulose) is mixed with the polyacrylate emulsion liquid, so-called lumps tend to occur, which is not preferable. In addition, the amount of the water-soluble polymer added is 0.1% to 2.0% of the amount of polyacrylate emulsion liquid.
% (weight), and if it is less than 0.1, the infiltration effect of the darkening treatment agent in the next step on the coating surface is weak, and
If it is more than 2.0%, the emulsion liquid tends to gel and become cheap, so the addition amount is preferably 0.5 to 1.5%.

In this way, the metal coating agent based on the present invention is applied to the surface of the desired sculpture, and after about 20 hours (about 1 day), a copper coating surface darkening treatment agent that does not contain the water-soluble organic solvent is applied. After being treated with the treatment agent, the copper coating on the surface of the sculpture gradually became darker and greener, and as expected, a sculpture with a patina-like copper color was obtained.

For example, in the case of a conventional metal coating agent made only of copper powder and polyacrylate emulsion, the polyacrylate emulsion forms a film after application, which hardens naturally, and gradually becomes incompatible with water, causing the aqueous solution to be repelled. It becomes easier. Therefore, the copper darkening agent cannot infiltrate into the surface of the copper coating, and accordingly, the darkening reaction becomes difficult to proceed.

On the other hand, the metal coating agent of the present invention has a water-soluble polymer dissolved in it as described above, and even after being applied to the surface of a sculpture and left for 20 hours (approximately 1 day), it remains a darkening metal treatment agent. When treated, a darkening reaction proceeds. This is because the polyacrylate and water-soluble polymer in the metal coating agent are uniformly dissolved, so when this coating agent is applied, the aqueous polymer is uniformly distributed in the film formed, which causes darkening. The metal treatment agent (aqueous solution) is absorbed and infiltrated into the coating, and a darkening reaction occurs when the surface of the copper powder in the coating comes into contact with the components in the treatment agent.

As described above, the metal coating agent based on the present invention is a mixture of copper powder and polyacrylate emulsion mixed with a small amount of water-soluble polymer. Even after being left in the sun, when treated with a darkening metal (copper) treatment agent, the color can be darkened in the same way as when the treatment is performed immediately after application of the conventional copper coating agent, as described above. Further, there is no need to mix a water-soluble organic solvent into the darkening metal treatment agent as in the above-mentioned application.

Furthermore, the preparation of the copper coating agent is simple, and the amount of water-soluble polymer added is small, so there is almost no problem in terms of cost. Furthermore, as mentioned above, darkened copper plastic objects can be produced freely without being restricted by time, and the finished product is also improved accordingly.

Next, examples based on the present invention will be shown.

Comparative Example 1 As a metal coating agent on the surface of a sculpture made of synthetic clay, 3 g of copper powder (passed through 100 meshes) was applied with 10 g of commercially available polyacrylate emulsion (solid content approximately 50%) [Pegal LS405 manufactured by Kouki Gas Kogyo Co., Ltd.] 3 hours after the paint film has dried, use a solution of 2 g of sodium sulfide (containing 5 molecules of crystalline water) dissolved in 50 c.c. of water as a darkening metal treatment agent. When the coating was applied, the treatment liquid did not blend into the coating surface and was repelled, making it impossible to darken the coating surface.

Example 1 Copper powder (100 mesh) was applied as a metal coating agent based on the present invention on the surface of a sculpture produced in the same manner as Comparative Example 1.
Comparative Example 1
Darkening treatment agent shown in (mainly consisting of alkali sulfide)
Unlike the comparative example, the treatment solution gradually and uniformly infiltrated the coating surface during treatment, and the color gradually darkened, and when this was left to stand, a bronze sculpture with an old patina was obtained.

Example 2 On the surface of a sculpture produced in the same manner as in Example 1, as a metal coating agent based on the present invention, 3 g of copper powder was added to 10 g of commercially available polyacrylate emulsion, and 0.05 g of methylcellulose (Metrose SM15 manufactured by Shin-Etsu Chemical Co., Ltd.) 20 hours after applying the solution, it was treated with a darkening treatment agent in which 2 g of potassium sulfide, 1 g of ammonium carbonate, and 2.8 g of ammonium chloride were dissolved in 100 c.c. of water, resulting in darkening as in Example 1. A bronze sculpture with green rust and a pale patina was obtained.

Claims (1)

[Claims] 1. A metal coating agent used to produce a copper coating surface of a sculptural object before a post-processing process with a darkening metal treatment agent, which is a mixture of copper powder and polyacrylic acid ester emulsion. A metal coating agent characterized in that it is made by adding and mixing polyvinyl alcohol or methyl cellulose in an amount of 0.1 to 2.0% based on the amount of the polyacrylic acid emulsion liquid. 2. The darkening metal treatment agent is a treatment liquid that darkens the metal (copper) coating surface by treating it, and is characterized by being an aqueous solution formed by adding an alkali sulfide or another inorganic salt to an alkali sulfide. The metal coating agent according to claim 1.