JP4079468B2 - Metallic coating structure and method for forming metallic coating - Google Patents

Description

【００３２】
【表２】

【００３３】
【発明の効果】
本発明によれば、グレー色下地塗膜の明度とメタリック塗膜の膜厚と光線透過率を特定の範囲に設定したことにより、実施例１で示したようにメタリック塗膜の膜厚が７μｍと薄くても１５μｍの膜厚差がある２２μｍの膜厚のものと比較しても色調の変動が少ない色差１．０以下の塗膜を得ることができる。また、メタリック塗膜が薄膜で形成されると光輝性材料の配向が平面的に均一になるために光輝感が上がり且つメタリックムラが生じないという効果が得られる。さらに、メタリック塗膜の形成時における有機溶剤の揮発量が減少し、しかも薄膜であるために塗装コストの削減につながるというメリットがある。
また、実施例２からわかるように、隠蔽膜厚を満足させるために従来行われていたような光輝性材料を増量したり、無機顔料や透明性の劣る有機顔料を配合しなくても、隠蔽膜厚３０μｍの塗色を最小乾燥膜厚１５μｍで形成することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel metallic coating structure and a method for forming a metallic coating, and more specifically, even if it is a metallic coating having a thickness thinner than that of a normal metallic coating, Even if it is a metallic coating that reduces the amount of glittering material added to satisfy or replenishing inorganic or organic pigments, it has excellent glitter feeling that does not cause color difference due to film thickness variation The present invention relates to a novel metallic coating structure that can be applied and a method for forming a metallic coating.
[0002]
[Prior art]
Conventionally, metallic coating has been widely performed. The metallic coating is usually coated with a coating film thickness (dry film thickness) of 15 to 25 μm in order to conceal the base, and the metallic coating is applied so that the light transmittance is 3% or less with this coating film thickness. In the film, a brilliant material, a chromatic pigment ordinarily used for coloring, and the like are blended. Of course, passenger cars, motorcycles, etc. painted with this metallic coating have no particular problems with the finishing itself, and are well received in the market.
However, the conventional metallic paint has a low solid content concentration of around 25%, so it contains a large amount of organic solvent, and the formed metallic coating is also a thick film of 15 to 25 μm as described above, so There is a problem that a large amount of the volatile organic solvent is present, so that a large amount of the organic solvent volatilizes from the coating film during or after the coating, thereby causing air pollution. For this reason, from the viewpoint of global environmental problems in recent years, there is a strong demand to reduce the amount of organic solvents emitted into the atmosphere.
[0003]
In addition to reducing organic solvents, the metallic coating cost is also reduced to 5 μm or more, for example, 5 to 15 μm, which is thinner than conventional films. It is desired to obtain a good metallic coating film that does not cause a color difference due to variations in film thickness even when it is formed thick. However, in the case of a thin film, there is a problem that it becomes difficult to conceal the base because the light transmittance becomes a low concealment coating of 3% or more.
[0004]
In addition, the conventional metallic coating film has to increase the content of glittering material in the metallic paint in order to conceal the base, or to blend inorganic pigments such as carbon black and organic pigments with poor transparency. There is a problem that the cost is increased, and furthermore, the color tone, saturation, and glitter cannot be satisfied, and further improvement is desired.
[0005]
As a method for solving the above-described problems, a method of using a color (co-color) base as the base coating of the metallic coating is also performed. However, in this case, there is a problem that the coating cost increases.
[0006]
However, a color difference of 0.5 or less is obtained by combining a specific gray intermediate coat having an average reflectivity in the range of ± 15% when a complete cover is used, using a conventional material with a low concealment. Has been proposed (Japanese Patent Publication No. 61-10190). However, this coating film formation method is intended for solid color coating, not a coating system that gives a radiant feeling like metallic coating, and when applied to a metallic thin film finish, There is a problem that a color difference is likely to occur due to variations in color.
[0007]
[Problems to be solved by the invention]
In the present invention, a uniform coating thickness is not obtained, and even if the thickness of the metallic coating film is 5 to 15 μm, which is thinner than the conventional metallic coating film, the film thickness variation, i.e., the film thickness difference. If the thickness is in the range of 15 μm or less, the object is to reduce the volatilization amount of the organic solvent into the atmosphere by obtaining a metallic coating film that does not cause a color difference and has excellent light luminance.
[0008]
Furthermore, the present invention does not increase the amount of glittering material used to satisfy the concealing film thickness (for example, 20 to 30 μm) in the conventional metallic coating film, and is an inorganic or transparent material used for the same purpose. The object is to obtain a metallic coating film excellent in glittering feeling that does not cause a color difference due to variations in film thickness when the difference in film thickness is 15 μm or less even if replenishment of inferior organic pigments is reduced. Is.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-described object, the present inventor has transmitted light on a gray-colored undercoat film having a specific brightness even if the film thickness of the metallic coat film is 5 to 15 μm, for example. It has been found that it can be easily achieved by laminating a transparent metallic coating having a rate of 10 to 25%, and the present invention has been completed.
[0010]
That is, the present invention
(1) A metallic coating film containing a glittering material is laminated on a gray base coating film, and the color difference (ΔE) is 1.0 or less within a range where the film thickness difference of the metallic coating film is 15 μm or less. In a certain metallic coating structure, the lightness (L value) of the gray base coating film is set within a range of L value +40 of the desired metallic coating film, and the metallic coating film has a glittering material in a pigment volume concentration. Light transmittance measured in the wavelength range of a desired metallic coating color at a wavelength of 400 nm to 700 nm with a dry film thickness of at least 5 μm which contains at least 1% and can form a continuous coating film is 10 to 25% A metallic coating structure characterized by a color, and (2) a metallic coating containing a glittering material is laminated on a gray undercoat, and the difference in film thickness of the metallic coating is 15 μm or less. In a range In a method of forming a metallic coating film having a difference (ΔE) of 1.0 or less, on a gray base coating film in which the lightness (L value) is set within a range of L value +40 of a desired metallic coating film, A light beam containing a glittering material at a pigment volume concentration of at least 1% and having a dry film thickness of at least 5 μm capable of forming a continuous coating film, measured in a wavelength range of a desired metallic coating color at a wavelength of 400 nm to 700 nm. The present invention relates to a method for forming a metallic coating film, wherein a metallic paint that forms a transparent color having a transmittance of 10 to 25% is applied.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The paint for forming the gray undercoat in the present invention comprises a base resin such as an alkyd resin, a polyester resin, an acrylic resin, and an epoxy resin, and a crosslinking agent such as an amino resin and a polyisocyanate as a vehicle component. This is an achromatic (gray) paint containing a white pigment and a black pigment of carbon black. In addition to the white pigment and the black pigment, a glittering material to be described later can be blended to make a silver color. The brightness of the gray undercoat is adjusted by appropriately changing the blending amount of the white pigment and the black pigment.
[0012]
The coating film thickness of the base coating is not particularly limited, but is generally in the range of 15 to 50 μm.
In the present invention, the metallic paint forming the metallic coating film is mainly composed of the vehicle component and the glittering material. Examples of the glitter material include metal pigments such as aluminum, stainless steel, nickel, and brass, pearl mica, and mica-like iron oxide (MIO). Further, in addition to the glittering material, chromatic pigments usually used for coloring are included.
[0013]
The glittering material is blended in the metallic paint in a pigment volume concentration (PVC) of at least 1%, but is blended in such an amount that the light transmittance of the metallic coating does not fall outside the range of 10 to 25%. Usually, it is mix | blended in 1 to 12% of range. If the blending amount of the glittering material is less than 1% PVC, a coating film having a metallic feeling cannot be obtained. On the other hand, if the blending amount exceeds 12%, a metallic coating composed of a composite color of the transparent color of the metallic coating film and the base coating film is not obtained. It becomes difficult to obtain a film.
[0014]
In the metallic coating structure of the present invention, a transparent or color clear layer is laminated on the metallic coating as necessary. As the clear layer, a transparent clear paint comprising the above-mentioned vehicle component or a color clear paint in which a transparent coloring pigment is blended in 5% or less of PVC is used. The coating thickness of the clear paint is generally in the range of 15 to 50 μm.
[0015]
In the metallic coating film structure of the present invention, the metallic coating film can form a continuous coating film and is formed with a film thickness of at least 5 μm. When the thin film is intended, it is formed with a film thickness of 5 to 15 μm. . In the case of a thin film, it is difficult to obtain a coating film having a color difference of 1.0 or less because a color difference is likely to occur due to variations in film thickness. However, in the present invention, the light transmittance of the metallic coating film is adjusted to 10 to 25% to make it transparent, and this transparent color is actively utilized to combine this with a gray base coating film having a specific L value. Thus, it is possible to obtain a metallic coating film having a color difference of 1.0 or less in a range where the film thickness difference is 15 μm or less.
[0016]
Here, the L value means a lightness index in Hunter's color difference formula obtained from tristimulus values X, Y, and Z defined in JIS Z28722. The color difference is a value measured by a MINORUTA spectrocolorimeter CM-1000 (manufactured by Minolta).
[0017]
Further, the light transmittance is a value measured in a wavelength range of a wavelength of 400 nm to 700 nm and a desired metallic coating color. For example, when the metallic coating has a blue color gamut, a range of 400 nm to 500 nm, yellow orange It is a value measured in a 550 to 650 nm region in the case of a system, and in a 600 nm to 700 nm region in the case of a red system. Usually, the light transmittance varies depending on the film thickness, but in the present invention, the metallic coating film is appropriately adjusted so as to have the light transmittance described above.
[0018]
In the metallic coating film of the present invention, in order to form the metallic coating film so that the color difference is 1.0 or less in the range where the film thickness difference is 15 μm or less, the selection of the gray base coating film is important. Then, it is necessary to select a base coating film having a specific L value, that is, a base coating film set within +40, preferably +0 to 40, based on the L value of a desired metallic coating film. If the L value of the base coating film deviates from the range of the above-mentioned L value of the metallic coating film within +40, the variation of the color tone of the metallic coating film is large, and a metallic coating film having a color difference of 1.0 or less cannot be obtained.
[0019]
Formation of the metallic coating film of the present invention is carried out by a method generally used in painting of automobiles, motorcycles and the like. That is, a gray base paint having a lightness within +40 of the desired metallic coating is applied to the surface of the object to be coated. As the coating method, methods such as spray coating, electrostatic air spray coating, and rotary atomizing electrostatic coating can be used.
[0020]
After the base paint is applied, the solvent is partially removed by leaving at room temperature for 2 to 10 minutes, followed by baking at 70 to 160 ° C. for 10 minutes to 1 hour. Then, the metallic paint is painted on it and baked under the same baking conditions, or the metallic paint is painted on it by the above-mentioned coating method without baking the base paint, and the two layers are simultaneously baked under the previous baking conditions. A metallic coating is obtained.
[0021]
When the clear paint is applied, it is baked under the same conditions as the above-mentioned base paint and metallic paint, but in general, the base paint, the metallic paint and the clear paint are each applied by wet-on-wet and baked. This method is applied by a three-coat two-bake method in which a base paint is baked, and a metallic paint and a clear paint are baked by wet-on-wet.
[0022]
【Example】
Next, the present invention will be described with reference to examples and comparative examples.
[0023]
Example 1
A paint A which gives five types of L values of 42, 53, 62, 70 and 82 using a melamine alkyd resin paint (trade name: Amirac, manufactured by Kansai Paint Co., Ltd.) as a gray base paint -E were prepared respectively.
[0024]
The obtained base paints A to E were applied to the surface-treated steel sheets so as to have a dry film thickness of 30 μm, and baked at 160 ° C. for 30 minutes. Next, a metallic paint (Kansai Paint Co., Ltd.) containing a light transmittance of 22%, an L value of 35, an aluminum powder pigment of 3% by PVC and an organic red pigment of 13.5% by PVC on the base coating film of the obtained coated plate. (Product name: Soflex 5100 red) is applied to a dry film thickness of 7 μm, and a clear paint (product name: Retan PG Clear, manufactured by Kansai Paint Co., Ltd.) is applied on the wet film to a dry film thickness of 25 μm. And then cured by heating at 80 ° C. for 30 minutes. Five types of metallic coating plates thus obtained were used as reference coatings.
[0025]
On the other hand, the metallic paint is applied on the five types of base coatings formed from the base paints A to E to a dry film thickness of 22 μm, and the clear paint is applied to a dry film thickness of 25 μm, followed by heat curing. A metallic coated plate was obtained. The color difference (ΔE) between the metallic coating film thus obtained and the reference coating film is shown in Table 1. In addition, the thing using the base coating material E corresponds to a comparative example.
[0026]
Example 2
The metallic paint soflex 5100 red color used in Example 1 was replaced with the pearl mica with 3.7% PVC and the organic red pigment with 5.5% PVC. The coating was carried out in the same manner as in Example 1 except that it was replaced with a material having a glittering material, light transmittance, lightness and dry film thickness, the same applies hereinafter. The results are shown in Table 1. In addition, the thing using the base coating materials D and E corresponds to a comparative example.
[0027]
Example 3
The metallic paint soflex 5100 red used in Example 1 is replaced with a pearl mica with 3.3% PVC, and an organic blue pigment with an organic blue pigment with 7.2% PVC. Was applied in the same manner as in Example 1 except that the values described in Table 1 were used, and the L value of the base paint was changed to that described in Table 2. The results are shown in Table 2 .
[0028]
Comparative Example 1
The coating was performed in the same manner as in Example 1 except that the metallic paint Soflex 5100 red used in Example 1 was replaced with one having the characteristic values shown in Table 1. As a result, as shown in Table 1, when the light transmittance increased to 31%, the color difference became 1 or more.
[0029]
Comparative Example 2
The coating was performed in the same manner as in Example 1 except that the metallic paint Soflex 5100 red used in Example 1 was replaced with one having the characteristic values shown in Table 1. As a result, as shown in Table 1, when the PVC of the glittering material was increased to 0.8% and the light transmittance was increased to 40%, the color difference became 1 or more.
[0030]
Comparative Example 3
Coating was performed in the same manner as in Example 1 except that the pearl mica-containing metallic paint used in Example 3 and Soflex 5100 blue were replaced with those having the characteristic values shown in Table 2 . As a result, as shown in Table 2, when the PVC of pearl mica was 0.7% and the light transmittance was 27%, the color difference was 1 or more.
[0031]
[Table 1]

[0032]
[Table 2]

[0033]
【The invention's effect】
According to the present invention, the lightness of the gray undercoat, the thickness of the metallic coating, and the light transmittance are set in specific ranges, so that the thickness of the metallic coating is 7 μm as shown in Example 1. Even if it is thin, a coating film having a color difference of 1.0 or less with little variation in color tone can be obtained even when compared with a film having a thickness of 22 μm with a film thickness difference of 15 μm. In addition, when the metallic coating film is formed as a thin film, the orientation of the glittering material becomes uniform in a planar manner, so that the effect of increasing the glitter feeling and preventing the occurrence of metallic unevenness can be obtained. Furthermore, there is a merit that the volatilization amount of the organic solvent at the time of forming the metallic coating film is reduced and the coating cost is reduced because of the thin film.
In addition, as can be seen from Example 2, the concealment can be achieved without increasing the amount of glittering material conventionally used to satisfy the concealment film thickness or blending an inorganic pigment or an organic pigment with poor transparency. A coating color with a film thickness of 30 μm can be formed with a minimum dry film thickness of 15 μm.

Claims (3)

The white pigment and a black pigment and an achromatic gray undercoating film containing a combination contains a luster material, formed by laminating a metallic coating film having variations in thickness, metallic coating film by thickness variation In the metallic coating structure in which the color difference (ΔE) is 1.0 or less within the range where the difference in thickness between the maximum film thickness and the minimum film thickness is 15 μm or less, the lightness (L value) of the gray base coating film is metallic coating The L value of the film is set within 0 to 40 , the minimum dry film thickness of the metallic coating film is 5 to 15 μm , and the metallic coating film contains a glittering material in a pigment volume concentration of 1 to 12% , Metallic thickness measured at a dry film thickness of at least 5 μm , when the color gamut of the metallic coating is blue, 400 nm to 500 nm, 550 nm to 650 nm for yellow orange, and 600 nm to 700 nm for red Light transmission through the coating Metallic coating film structure rates is characterized in that it is a color transparent 10-25%.   2. The metallic coating structure according to claim 1, wherein a transparent or color clear coating is laminated on the metallic coating. Maximum of metallic coating film due to film thickness variation by laminating metallic coating film containing brilliant material and varying film thickness on achromatic gray base coating film containing white pigment and black pigment In the method of forming a metallic coating film in which the color difference (ΔE) is 1.0 or less within the range where the difference between the thickness and the minimum film thickness is 15 μm or less, the lightness (L value) is the L value of the metallic coating film + 0 on the set gray undercoating film to 40 within a minimum dry film thickness of the metallic coating film formed is 5 to 15 [mu] m, the luster material contains 1-12% pigment volume concentration, at a minimum Light transmittance measured in a dry film thickness of 5 μm when the color gamut of the metallic coating is blue, 400 nm to 500 nm, 550 nm to 650 nm for yellow orange, and 600 nm to 700 nm for red. transparent but of 10% to 25% Metallic coating film method forming, which comprises coating the metallic coating to form a metallic coating film is.