JPH09262544A - Surface coating film structure of metal material and method for forming it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve corrosion resistance, cost reduction and recycling properties while brightness and high quality feeling is kept by forming successively a resin electrodeposition coating layer, a resin powder coating layer, a metal or metal compd. layer and a resin top coat layer on a basis of a metal material such as an aluminum wheel. SOLUTION: In this surface coating structure of a metal material 1 such as an aluminum alloy wheel, a resin electrodeposition coating layer 2, a resin powder coating layer 3, a metal or metal compd. layer 4 and a resin top coat layer 5 are successively formed on a basis of a metal material 1. In this instance, the layer 3 and the layer 5 are clear layers and the layer 4 is pref. formed of a dry plating layer of a metal selected from aluminum, chromium nitride, titanium nitride and gold. In addition, the electrodeposition layer 2 is a resin layer formed by means of electrodeposition so as to tightly stick the resin on the basis of the metal material 1. In addition, a primer is applied on the layer 4 so as to improve interlocking properties and adhesion properties between the top coat layer 5 and the layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating structure on a metal material surface and a coating forming method.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a film structure on the surface of a metal material such as an aluminum wheel, Japanese Patent Application Laid-Open No.
No. 2 publication is known. There, after the surface of the metal material is shot blasted, the surface is subjected to powder coating and ground treatment, and the underlayer is undercoated as an intermediate layer. I have.

[0003]

However, the conventional method has the following problems. The powder coating layer has low adhesion to a metal substrate, and cracks occur due to a difference in thermal expansion and a cushion. Therefore, corrosion resistance and durability are low. Since chromium is used for the glitter, the cost increases. Since a metal (chromium) different from aluminum is used, it is difficult to recycle aluminum. An object of the present invention is to provide a metal material surface coating structure and a method for forming the same, which can improve corrosion resistance, cost reduction, and recyclability while maintaining the brilliancy and luxury feeling equal to or higher than the conventional chromium plating type. Is to provide.

[0004]

The present invention to achieve the above object is as follows. (1) A metal material surface coating structure in which a resin electrodeposition coating layer, a resin powder coating layer, a metal or metal compound layer, and a resin topcoat layer are sequentially formed on a base material of a metal material. (2) The metal material surface coating structure according to (1), wherein the metal material is an aluminum alloy wheel. (3) The metal material surface coating structure according to (1), wherein the powder coating layer and the top coat layer are clear layers. (4) The metal or metal compound layer is a dry plating layer of at least one metal selected from the group consisting of aluminum, chromium nitride, titanium nitride and gold (1) or (2) The surface coating structure of the metal material described. (5) a step of forming a resin electrodeposition coating layer by electrodeposition coating a resin coating material on a metal base, and powder coating the resin coating material onto the resin electrodeposition coating layer A step of forming a powder coating layer, a step of forming a layer of a metal or a metal compound on the powder coating layer of the resin by, for example, dry plating, and a resin coating on the plating layer of the metal And a step of forming a resin top coat layer, and a method of forming a metal surface coating structure.

In the methods of forming the metal material surface coating structure of (1) and (2) and the coating structure of (6), the metal or metal compound layer is, for example, a dry plating layer. Since electrodeposition coating plus powder coating is used, the electrodeposition coating layer has better adhesion to the metal base and is denser than the powder coating layer. It is improved compared to body painting plus intermediate layer structure. In the metal material surface coating structure of the above (4) and (5), even if the metal or metal compound layer is not pure chromium (for example, an inexpensive aluminum layer), the base color (for example,
Black system) can be transmitted to some extent to give a deep sense of high quality (color as if it were chrome plating), and the cost can be reduced by not using chrome. In addition, when the metal material is an aluminum wheel, the same kind of metal is formed by making the plating layer an aluminum layer, which facilitates recycling of the aluminum wheel.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The metal material surface coating structure of the present invention comprises:
As shown in FIG. 1, a base material of a metal material 1 is coated with a resin electrodeposition coating layer 2, a resin powder coating layer 3, a metal or metal compound layer 4 (for example, a metal plating layer), and a resin topcoat. It consists of a structure in which the layer 5 is formed in order. The metal base may be a metal base, for example, an aluminum alloy, a magnesium alloy, iron, or the like. The metal 1 is an arbitrary member made of metal, for example, an aluminum alloy wheel.

The electrodeposition coating layer 2 may be a resin layer formed by electrodeposition coating so as to be in direct contact with the base material of the metal material 1, for example, a coating layer of an epoxy-based cationic electrodeposition coating. Has a thickness of 10 to 30 μm. The reason for this range is that if the thickness is less than 10 μm, cast surface appears, and if the thickness is more than 30 μm, sagging occurs. The electrodeposition coating layer 2 has much better adhesion and adhesion to the metal substrate than the powder coating layer, and since it is dense and hard, it can fill the small irregularities of the substrate, and the resistance of the coating structure can be improved. Improves releasability and corrosion resistance. The electrodeposition coating layer 2 is colored, and in order to make the appearance of the coating structure similar to chrome, it is colored in a blackish color.
The coloring is not limited to the black type, and the appearance of the coating structure can be a color in which the color of the undercoat appears. For example, in order to make the appearance of the coating structure bluish, the coloring of the electrodeposition coating layer 2 can be changed. It is blue.

The powder coating layer 3 may be a resin layer formed by powder coating so as to be in direct contact with the electrodeposition coating layer 2, and may be, for example, an epoxy, acrylic or polyester powder coating. Consisting of a painted layer. Paint particle size is 3
６6 μm, and the thickness of the layer 3 is 60-150 μm. This range of values is a value for ensuring the corrosion resistance of the base material in cooperation with the electrodeposition coating layer 2. The adhesion and adhesion between the powder coating layer 3 and the electrodeposition coating layer 2 are good because of resin and resin adhesion. The powder coating layer 3 has a larger paint grain than the electrodeposition coating layer 2 and can fill large irregularities quickly. The reason why the powder coating layer 3 is formed on the upper side of the electrodeposition coating layer 2 is to form a corrosion-resistant layer having a required thickness quickly and inexpensively. When the electrodeposition coating layer 2 is colored, the powder coating layer 3 is a clear (transparent) layer, or the same color as the electrodeposition coating layer 2 is colored.

The metal or metal compound layer 4 is made of, for example, at least one metal (including a pure metal and an alloy) selected from the group consisting of aluminum, chromium nitride, titanium nitride, and gold.
It is composed of a dry plating layer. Metal plating layer 4
May be composed of a metal other than these, and may be chromium if the cost may be as high as that of the conventional chromium plating layer. When the metal or metal compound layer 4 is aluminum, the black color from the underlayers 2 and 3 is slightly transmitted and approaches the color of chrome plating and has a deep color. By using aluminum, the cost can be reduced more than in the case of chromium. However, the thickness of the metal or metal compound layer 4 is set to 0.04 to 1.1 μm in order to transmit an appropriate amount of the color of the base. If it exceeds 1.1 μm, it becomes difficult to transmit the color of the underlayer, and the appearance of the color of the underlayer becomes poor. If it is less than 0.04 μm, it becomes difficult to form the layer 4. Dry plating may be performed by any of sputtering, ion plating, and vapor deposition. In order to improve the adhesion and adhesion between the metal or metal compound layer 4 and the underlying powder coating layer 3, before forming the metal plating layer 4, a primer 6 (undercoating) is formed on the powder coating layer 3. Therefore, for example, an epoxy-based metallic primer is used)
You may apply | coat about 10-10 micrometers.

The resin topcoat layer 5 is a clear coating layer (which is clear so as not to impair the high-quality color of the base and the metal layer), and is made of an acrylic, urethane or epoxy resin coating. It is formed by air spray coating (electrostatic coating may be used). Any thickness may be used as long as it can protect the metal or metal compound layer 4, for example, about 10 to 40 μm.
The reason for setting this area is that even if the area is thicker than about 40 μm, the protection function does not increase or it takes time to form the protection function.
This is because if it is thinner than about 0, the protective function becomes insufficient. In order to improve adhesion and adhesion between the top coat layer 5 and the metal or metal compound layer 4, the top coat layer 5
Prior to the formation of the above, a primer 7 (for example, an epoxy-based metallic primer) may be applied on the metal or metal compound layer 4 to a thickness of about 5 to 10 μm.

The method of forming the surface coating structure of a metal material according to the present invention comprises a step of forming a resin electrodeposition coating layer 2 by electrodeposition coating a resin coating material on the base material of the metal material 1, and a resin electrodeposition coating. Layer 2
A step of forming a resin powder coating layer 3 by powder coating a resin coating on the above, and a step of forming a metal or metal compound layer 4 on the resin powder coating layer 3 by dry plating, A step of forming a resin top coat layer 5 by applying a resin paint on the metal or metal compound layer 4.

In the step of forming the layer 2 by electrodeposition coating, first, the base material of the metal material 1 is degreased and washed with water, and then the electrodeposition coating is carried out using, for example, an epoxy-based cationic electrodeposition coating which is colored black. In electrodeposition coating, a DC voltage (for example, 210 to 23) is applied between the metal material 1 which is an electric conductor and an electrode in an electrodeposition tank (temperature is, for example, 27 ° C.) filled with a low concentration aqueous coating material.
0 V) is applied for 2 to 3 minutes, and the fine particles of the coating material dispersed in water are attracted to the metal material 1 by an electric force to coagulate and deposit to form a coating film. The cationic electrodeposition paint is a cathodic deposition paint based on a resin having an onium group such as a basic amino group, ammonium and sulfonium and neutralized with an acid such as a lower organic acid. In the cationic electrodeposition, since the coating is basic, there is no elution of metal ions, which is advantageous for the alkali resistance and corrosion resistance of the coating. Also, coloring during coating of the coating film is small. The coating thickness is 10 to 30 μm. After painting,
Bake and dry in a furnace at 200-210 ° C for about 10-25 minutes. The coating film thus formed is dense and hard,
It fills small irregularities in the base material, has excellent adhesion and adhesion to the base material, protects the base material, and greatly improves the corrosion resistance of the base material compared to conventional powder coating.

In the step of forming the layer 3 by powder coating, a high DC voltage (30 to 90 kV) is applied between the grounded object to be coated (the metal material 1 having the layer 2 formed) and the electrode of the gun, On the other hand, an acrylic, polyester, or epoxy-based clear powder coating (having a particle size of about 3 to 6 μm and preheated to about 200 ° C.) is jetted from the gun by aerodynamic force. The powder particles dispersed in the air collide with the ionized air generated by the corona discharge generated at the gun electrode and become charged.They move toward the coating object by the action of the electrostatic field between the gun and the coating object and the air flow, Adsorbs to the surface of the substrate by force. Powder coating is suitable for thick coating, fills relatively large irregularities, and makes the surface suitable for forming a metal film. The layer 3 is formed to have a thickness of 60 to 150 μm. After painting, in a furnace at about 170 ° C, about 20
Bake and dry for ~ 30 minutes.

In the step of forming the metal or metal compound layer 4 by, for example, dry plating, a metal (pure metal or alloy) such as aluminum, chromium nitride, titanium nitride or gold is sputtered (on a surface of metal, plastic or the like). , A known operation for depositing a thin layer of metal in a vacuum), ion plating, or vapor deposition on the layer 3 of the metal material 1 to a thickness of 0.04 to
1.1 μm is formed. For example, aluminum is formed to a thickness of 0.1 μm. In this case, it is possible to inexpensively produce a deep (high-quality) chrome-like color that is slightly transmitted through the underlying black color (different from the light shade of aluminum only).

In the step of forming the top coat layer 5, in the booth, an acrylic, urethane, or epoxy clear powder coating is sprayed onto the preheated object using a powder spraying gun. , Melt, attach (so-called,
Spray method). The spraying method may be changed to powder electrostatic coating. The top coat layer 5 is formed to a thickness of 20 to 40 μm. The top coat layer 5 thus formed functions as a protective layer for the metal layer 4.

[0016]

EXAMPLE An aluminum wheel was selected as the metal material 1, and a film structure was formed on the surface thereof as follows. First, the surface of the aluminum wheel was degreased and washed with water. Next, an epoxy diameter cationic electrodeposition coating (trade name: Nippe Power Top U-
600, black line) at a temperature of 27 ° C. for 2 to 3 min. ,
Electrodeposition coating was performed under the conditions of 210 to 230 V to form an electrodeposition coating layer 2 having a thickness of 20 μm. The layer 2 is then heated to a temperature of 20
It was baked and dried at 0 to 210 ° C for 18 minutes. Next,
Acrylic powder paint (4-5 μm, clear), 40-
Under the voltage condition of 60 kV, the thickness is about 100 μm on the layer 2.
m, electrostatic powder coating, baking at 170 ° C. for 25 minutes, and drying to form a powder coating layer 3. Then, aluminum was sputtered to form a metal film 4 on the layer 3 with a thickness of 0.1 μm. Next, a metal primer having a thickness of 5 to 10 μm was applied to the base, and then clear powder coating (trade name: Nippesparac 5000BF) was blown on the air to form a topcoat layer 5 having a thickness of about 25 μm. Then, it was baked and dried at 140 ° C for 25 minutes.

As shown in FIG. 2, the coating structure was formed not only on the front surface 8 of the wheel but also on the entire length of the inner surface 9 of the drop portion of the rim (conventionally, only the front surface of the wheel). The aluminum wheels manufactured in this way shine the blackness of the base,
It had a deep shade. In addition, by selecting a black system as the base color, the yellowish color of the plating itself becomes inconspicuous due to the black system color, and becomes just a mirror color. In addition, since the coating range has been expanded not only to the front of the wheel but also to the entire length of the inner surface of the drop portion of the rim, the front surface of the wheel draws a transparent color tone effect. The effect is great. In addition, the temperature 39 ° C 24 hours, -18
A thermal endurance test was conducted for 10 hours at 20 ° C for 4 hours at room temperature, but no peeling or cracking was observed in the coating structure.
It has been found that there is good durability. In addition, a corrosion resistance test was performed by repeating immersion in acidic solution of pH 2 for 1 minute and then in distilled water of pH 7 for 1 minute 2,000 times.
No chemical erosion was observed on the aluminum substrate under the coating structure, and it was also found that the wheel has good corrosion resistance due to the coating structure.

[0018]

According to the structure of claim 1, a resin electrodeposition coating layer, a resin powder coating layer, a metal or metal compound layer, and a resin topcoat layer are sequentially formed on a base material of a metal material. Therefore, the base treatment of the plating is electrodeposition coating plus powder coating, and the corrosion resistance and crack resistance are improved compared to the conventional powder coating plus intermediate layer structure. According to the structure of claim 2, since the metal material is an aluminum alloy wheel, the corrosion resistance of the aluminum wheel can be improved. According to the structure of claim 3, since the powder coating layer and the top coat layer are the clear layers, the color tone produced by the electrodeposition coating layer and the plating layer is influenced by the colors of the powder coating layer and the top coat layer. I will not receive it. According to the structure of claim 4, the metal or metal compound plating layer is made of a metal other than pure chromium such as aluminum, so that the metal of the plating layer is combined with the material of the metal material (for example, an aluminum wheel). As a result, the cost of plating can be reduced and the recycling (collection and reuse) of metal materials can be facilitated. According to the method of claim 5, a resin coating material is electrodeposited on a base material of a metal material, a powder coating layer is formed on the base material, and a metal or metal compound layer is formed on the powder coating layer. Since the resin top coat layer is formed on the product, the finished product has the same effect as that of claim 1.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a metal material surface coating structure according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an aluminum wheel to which a metal material surface coating structure according to one embodiment of the present invention is applied.

[Explanation of symbols]

 1 Metal Material 2 Electrodeposition Coating Layer 3 Powder Coating Layer 4 Metal or Metal Compound Layer 5 Topcoat Layer 6, 7 Primer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B05D 7/24 301 B05D 7/24 301A (72) Inventor Kishiro Abe 5 Yonbancho, Chiyoda-ku, Tokyo Address 9 Within Topy Industries, Ltd. (72) Inventor Kenji Tsuchida 1 share company at 478 Yoda, Fujisawa City, Kanagawa Nitto inside (72) Inventor Shinichiro Gazuma 1 share association at 478 Yoda, Fujisawa City, Kanagawa Prefecture Nitto company

Claims (5)

[Claims] 1. A metal material surface coating structure in which a resin electrodeposition coating layer, a resin powder coating layer, a metal or metal compound layer, and a resin topcoat layer are sequentially formed on a metal material substrate. 2. The metal material surface coating structure according to claim 1, wherein said metal material is an aluminum alloy wheel. 3. The metal material surface coating structure according to claim 1, wherein the powder coating layer and the top coat layer are clear layers. 4. The dry plating layer of at least one metal selected from the group consisting of aluminum, chromium nitride, titanium nitride, and gold, wherein the metal or metal compound layer is formed by a dry plating layer. Metal material surface coating structure. 5. A step of forming a resin electrodeposition coating layer by electrodeposition coating a resin coating material on a metal base, and powder coating the resin coating material on the resin electrodeposition coating layer. A step of forming a resin powder coating layer, a step of forming a metal layer on the resin powder coating layer by dry plating, and a resin coating by coating a resin coating on the metal or metal compound layer. Forming a top coat layer, and forming a metal material surface coating structure.