KR100383344B1 - Process of Lastar coating - Google Patents

Abstract

The present invention relates to a spray plating method for forming a silver film by depositing silver by a silver head reaction by spraying a silver nitrate solution and a reducing agent solution with a two head spray gun, respectively, on a surface of a workpiece.

The present invention does not cause environmental pollution compared to the conventional plating method and can produce a low-cost silver plated product with high productivity.

Description

Spray plating method {Process of Lastar coating}

The present invention relates to a spray plating method for forming a silver film using a silver diameter reaction on the surface of all materials (metal, plastic, rubber, wood, etc.) requiring surface protection treatment by a liquid spray method.

More specifically, the present invention relates to a spray plating method for economically forming a silver film without causing environmental pollution.

The conventional silver hardening reaction has many problems in practical use because of the problem that the use time of the mixed liquid is limited because the silver liquid and the reducing liquid are mixed in respective amounts to form an electroless plating bath.

In addition, electroplating is a method of plating the material to be treated and the metal material to be obtained by supplying + power and-power in the electrolytic solution. This method emits heavy metals such as cyanide and hexavalent chromium, which are environmentally harmful substances. Wastewater treatment requires a lot of cost and equipment, causes environmental pollution, and is limited to materials because it is applied only to conductors. In addition, the vacuum evaporation plating method uses a certain closed space in a vacuum state to gasify metals and oxides, etc. It is a method of ionizing and depositing on the surface of the material. This method has a high capital investment and low productivity due to the limitation of throughput.

The present invention is to provide a spray plating method for forming a silver film using a silver diameter reaction on the surface of all materials without contaminating the environment and without being limited to the material at low cost.

1 is an enlarged cross-sectional view of a product produced by the present invention.

The present invention is described in detail as follows.

1 is a cross-sectional view of a silver film product produced by the spray plating method of the present invention, 1 is a material, 2 is a coating film such as an epoxy paint, 3 is an uneven surface, 4 is a silver film, 5 is a transparent protective film such as a polyurethane film. .

The present invention comprises a material pretreatment step, an epoxy coating step, a surface conditioner treatment step, a washing step, a spray plating step, a washing step, a drying step, and a polyurethane resin coating step.

Hereinafter, the present invention will be described in detail for each process.

After the pre-treatment to remove foreign matter (dust, oil, etc.) from the surface of the material (1) to be applied using alkali or solvent, a coating film (2) such as epoxy paint is applied to improve the surface smoothness and corrosion resistance of the treated surface. To form.

Tin chloride (SnCl ₂ ) solution, a surface modifier, is sprayed onto the epoxy coating film 2 to improve adhesion with silver (Ag) to form a fine concave surface (3), and the residue is washed with pure water to remove the residue. do.

Thereafter, the spray plating solution is sprayed at the same time by spraying the plating solution A (silver liquid) and the reducing solution B (ammonia water, etc.) using a two-head spray gun using compressed air to deposit silver (Ag) by the silver diameter reaction. 4) get

At this time, in order to remove incomplete reactants and by-products generated during the reaction, water is evaporated using pure air and hot air after washing with pure water.

In order to protect the silver film 4 produced here, a transparent paint is applied on the silver film 4 to form a transparent protective film 5 to provide weather resistance and durability of the silver film 4.

When applying a clear paint, a small amount of dye is added so that the unique colors of various metals can be expressed (chrome, titanium, gold, etc.).

Example

To remove foreign substances on the surface of the material (1), remove the foreign substances adhering to the material using an alkali degreasing agent or solvent, and then apply epoxy paint with a thickness of 15 to 20㎛ using a paint gun and leave them in an 80 ℃ drying furnace for 30 minutes After obtaining the coating film 2 of the uniform epoxy paint, liquid tin chloride (SnCl ₂ ) is added to the coating film ₂ for the purpose of improving adhesion between the coating film 2 and the silver film and forming a uniform silver film. It is sprayed for a second (0.7-1.2kg / cm 2 hydraulic pressure) to make the surface of the epoxy coating film 2 become the fine concave surface 3, and it is pure water for 2-3 seconds to remove the tin chloride which remains on the coating film 2 surface. It wash | cleans (0.7-1.2 kg / cm <2> water pressure).

The spray plating solution was then sprayed with silver nitrate (AgNO ₃ ) plating solution (A) and ammonia water reducing solution (B) using a twin head gun (TWO HEAD SPRAY GUN) using compressed air (2 to 3㎏ / ㎠). Silver (Ag) is deposited to form a uniform silver film 4 (thickness: 0.3 µm).

2AgNO ₃ + 2NH ₃ + H ₂ O-Ag ₂ O + 2NH ₄ NO ₃ (1)

Ag ₂ O + 4 NH ₃ + H ₂ O- ₂ Ag (NO ₃ ) ₂ OH (2)

Ag (NO ₃ ) ₂ OH-Ag + 2 NH ₃ + H ₂ O (3)

At this time, in order to remove the incomplete reactants and by-products generated during the reaction, the silver film 4 is washed with pure water for 2 to 3 seconds (water pressure of 0.7 to 1.2 kg / cm 2), and then the compressed air (1 to 2 kg / ㎠) for 2 to 3 seconds to remove the water first and then left in a 50 ℃ drying furnace for 10 minutes to completely remove the water.

Since the silver film 4 produced here changes color and physical properties according to the surrounding environment, a urethane, acrylic or other synthetic resin transparent paint is applied on the silver film 4 using a paint gun to protect the silver film 4. It is applied in a thickness of 占 퐉 and left for 30 minutes in an 80 ° C drying furnace to form a uniform transparent protective film (5).

When applying a transparent paint, a small amount of dye is added to the paint to obtain colors unique to various metals.

<Coloring ratio of applied dye>

Chromium Color: Use 1 ~ 2% of the colorant dye (black: blue: red = 80: 10: 10) in a transparent paint.

Titanium color: 4 ~ 5% mixed color with transparent dye (black: blue = 90:10) by weight ratio.

Gold color: 2 ~ 3% mixed color by transparent dye (yellow: black: red: blue = 54: 26: 16: 4).

The results of comparing and evaluating the products manufactured by the examples and the products prepared by the conventional method are shown in Table 1, and the results of testing the detection of harmful substances (heavy metals) from the products prepared by the examples are shown in Table 2 and same.

<Table 1>

Compare Original product Example (Product of the Invention) Electroplating Vacuum deposition quality External appearance pencil strength impact adhesion corrosion resistance ○ 2-7H ○ ◎ ○ ○ 3H ○○○ ○ 3H ○○○ Environmental friendliness Teen Jockey Zicycling ×××× Not possible ◎◎ Partial possible ○○ possible Economics Productive Material Responsiveness △ ×× ×× △ ◎ ○

* ◎: Very good, ○: Good, △: Normal, ×: Bad, ××: Worse,

×××: Very bad

<Table 2>

Test Items unit Result Remarks PbCdCr6 Weight ppm Weight ppm ㎍ / ㎠ Not detected Not detected Not detected

Test Center: Korea Testing and Research Institute (TKA-006134)

The present invention solves the disadvantages of the electroplating, vacuum deposition plating which is a conventional surface treatment method as a practical technology of silver hardening reaction using an environmentally friendly material.

That is, the present invention can prevent environmental pollution by heavy metals discharged during electroplating, and can diversify the applied materials so that all industries (in-vehicles, exterior materials, home appliances, building materials, lighting equipment, religious objects, other accessories) ) Can be widely used.

In addition, since the present invention is a method of forming a silver film by the liquid injection method, it is easy to automate, thereby improving productivity, and economically manufacturing a silver film product.

Claims (3)

The silver film (Ag) is formed by the silver mirror reaction by simultaneously spraying the silver nitrate (A) and the reducing agent (B) onto the respective guns with a twin head gun using compressed air on the surface of the workpiece. Spray plating method characterized in that to make. 2. The spray plating method according to claim 1, wherein an epoxy-based coating film is formed on the surface of the material to be treated before forming the silver (Ag) film, and liquid tin chloride is sprayed on the surface to form an uneven surface. The spray plating method according to claim 1, wherein the silver film surface is coated with a transparent paint of various metal colors (chrome, titanium, gold, etc.).