Vehicle exterior parts, roof rails

Abstract

Provided is a roof rail (1) comprising: a base part (2) formed from a resin; and a coating film (10) having metallic luster and covering a surface of the base part (2). The coating film (10) comprises a primer film (3) adhered to the surface of the base part (2) and a metal-containing coating film (4) covering the surface of the base part (2) with the primer film (3) therebetween. The thickness of the metal-containing coating film (4) is greater than the thickness of the primer film (3).

Description

Vehicle exterior parts

[0001] This application claims priority from Japanese Patent Application No. 2023-182683, filed on October 24, 2023, the contents of which are incorporated herein by reference.

[0002] For example, as shown in Patent Document 1, roof rails for carrying luggage are sometimes attached to the roof of a vehicle. Generally, two such roof rails are installed spaced apart in the vehicle width direction, and the two rails form a pair to support luggage from below.

[0003] Japanese Patent Application Publication No. 2009-143276

[0004] Vehicles are equipped with various exterior vehicle components, such as roof rails shown in Patent Document 1. Vehicle exterior components have a significant impact on the vehicle's appearance. For example, metallic luster may be required for such exterior vehicle components. However, forming the entire exterior vehicle component out of metal increases material costs and weight. For this reason, many exterior vehicle components are manufactured with a resin base plated. However, because plating requires large-scale equipment, a simpler method has been proposed: forming a metal-containing coating film on a resin base. However, the metal-containing coating film is formed so as to cover a primer film formed on the surface of the base. In this case, the color of the primer film may be visible from the outside through the metal-containing coating film.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to prevent the color tone of a primer film from being visible to outsiders through a coating film containing metal in a vehicle exterior part whose base is made of resin.

[0006] The present invention employs the following configuration as a means for solving the above problems.

[0007] A first aspect of the present invention is an exterior vehicle part comprising a base made of resin and a coating film having a metallic luster and covering the surface of the base, wherein the coating film has a primer film adhered to the surface of the base and a metal-containing coating film sandwiching the primer film and covering the surface of the base, and the film thickness of the metal-containing coating film is greater than the film thickness of the primer film.

[0008] A second aspect of the present invention is the first aspect, wherein the film thickness of the metal-containing coating film is at least twice the film thickness of the primer film.

[0009] A third aspect of the present invention is the first or second aspect, wherein the coating film covers the metal-containing coating film from the side opposite to the primer film and has a transparent protective film.

[0010] A fourth aspect of the present invention is the third aspect, wherein the primer film has a thickness of 5 to 10 μm, the metal-containing coating film has a thickness of 20 μm, and the protective film has a thickness of 20 to 30 μm. A fifth aspect of the present invention is a roof rail comprising the vehicle exterior part of any one of the first to fourth aspects. A sixth aspect of the present invention is the fifth aspect, wherein the surface of the base is an outer surface facing the outside of the vehicle, and the coating film is formed to cover the outer surface.

[0011] In the above aspect of the present invention, the metal-containing coating film is thick and the primer film is thin. According to the above aspect of the present invention, it is possible to prevent external light from entering the primer film through the metal-containing coating film. Furthermore, even if external light reaches the primer film, the metal-containing coating film is formed thick, so that it is possible to prevent external light reflected by the primer film from being emitted to the outside through the metal-containing coating film. Therefore, according to the above aspect of the present invention, in a vehicle exterior part having a base made of resin, it is possible to prevent the color tone of the primer film from being visible to outsiders through the metal-containing coating film.

[0012] Fig. 1 is a perspective view of a roof of a vehicle having roof rails according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of a left roof rail, which is one of the roof rails according to an embodiment of the present invention, taken along line II-II in Fig. 1. Fig. 3 is a schematic diagram showing the cross-sectional structure of the cross-sectional view of the left roof rail, which is one of the roof rails according to an embodiment of the present invention.

[0013] Hereinafter, an embodiment of a vehicle exterior part according to the present invention will be described with reference to the drawings. In this embodiment, an example in which the configuration of the vehicle exterior part according to the present invention is applied to a roof rail will be described.

[0014] 1 is a perspective view of a roof 101 of a vehicle 100 having a roof rail 1 of this embodiment. As shown in this figure, the roof rail 1 of this embodiment is an elongated component that is long in the front-to-rear direction of the vehicle 100. Two roof rails 1 of this embodiment are provided for the vehicle 100. These roof rails 1 of this embodiment are arranged at intervals in the vehicle width direction and are arranged parallel to each other.

[0015] The roof rail 1 located on the left side of the vehicle 100 is referred to as the left roof rail 1A. The roof rail 1 located on the right side of the vehicle 100 is referred to as the right roof rail 1B. The left roof rail 1A and the right roof rail 1B are formed to be symmetrical. For this reason, in the following description, the structure of the left roof rail 1A will be described in detail with reference to the drawings, and a detailed description of the structure of the right roof rail 1B will be omitted.

[0016] FIG. 2 is a cross-sectional view of the left roof rail 1A, and corresponds to the cross-sectional view taken along line II-II in FIG. 1. As shown in FIG. 2, the left roof rail 1A has a main body wall portion 1a. As shown in FIG. 2, the main body wall portion 1a is a hollow member formed to have a substantially hemispherical cross-sectional shape. The main body wall portion 1a is formed so as to open downward. An outer wall surface 1b of such main body wall portion 1a is an exposed surface that can be seen from outside the vehicle 100. Note that an inner wall surface 1c of the main body wall portion 1a is a surface that cannot be seen from outside the vehicle 100.

[0017] The left roof rail 1A also includes a fastening portion (not shown) that is fastened to the vehicle body, an engaging portion (not shown) that engages with the vehicle body, etc. The left roof rail 1A is fixed to the vehicle body via these fastening portions, engaging portions, etc.

[0018] 3 is a schematic diagram showing the cross-sectional structure of the left roof rail 1A. As shown in this figure, the left roof rail 1A has a base 2, a primer film 3, a metal-containing coating film 4, and a clear coating film 5 (protective film). Of these, the primer film 3, the metal-containing coating film 4, and the clear coating film 5 constitute a coating film 10 that covers the surface of the base 2.

[0019] The base 2 is formed of resin. For example, the base 2 is formed of polycarbonate (PC) or polyethylene terephthalate (PET). Such a base 2 can be formed, for example, by injection molding of resin. Such a base 2 is the main portion of the main body wall 1a, and like the main body wall 1a, has a substantially hemispherical cross-sectional shape. In other words, the base 2 has an outer surface 2a, which is a surface facing the outside of the vehicle 100 (a surface visible from the outside), and an inner surface (not shown), which is a surface opposite the outer surface 2a (a surface not visible from the outside). Note that the base 2 may form the above-mentioned fastening portion or engaging portion.

[0020] The primer film 3 is a film for improving the smoothness and adhesion of the surface on which the metal-containing coating film 4 is formed. The surface of the base 2 has more irregularities than the surface of the primer film 3. In contrast, the surface of the primer film 3 has fewer irregularities than the surface of the base 2. By forming the metal-containing coating film 4 on the base 2 via such a primer film 3, the adhesion of the metal-containing coating film 4 to the base 2 is improved.

[0021] Such a primer film 3 can be formed by applying paint before drying to the surface of the base 2 and then drying the paint after application. For example, the primer film 3 has a black color tone. Such a primer film 3 is formed to a film thickness of, for example, 5 to 10 μm. Note that the color of the primer film 3 may be other than black.

[0022] The thickness of the primer film 3 in this embodiment is smaller than the thickness of commonly used primer films (e.g., 20 to 25 μm). A primer film 3 with such a small thickness prevents solvent components contained in the paint from remaining inside the primer film 3 before drying. This makes it possible to prevent solvent components remaining inside the primer film 3 from affecting the metal-containing coating film 4.

[0023] The metal-containing coating film 4 is a coating film containing a metal-containing luster paint. For example, the metal-containing coating film 4 can be formed using a luster paint containing metal flakes such as aluminum in a solvent. The solvent contains, as a main component other than the metal flakes, a water-soluble resin, for example. The water-soluble resin is, for example, black. For example, the metal flakes are shaped like scales with a thickness of 100 nm or less and are treated to impart hydrophobicity to the surface. For example, the metal-containing coating film 4 can be formed by applying a luster paint to the primer film 3 and then drying it. During the drying process of such a luster paint, the hydrophobic surface of the metal flakes rises to the surface of the water-soluble resin, and multiple metal flakes are densely arranged on the surface of the coating film, thereby exhibiting luster. In other words, for example, such a metal-containing coating film 4 has metal flakes densely arranged on the surface of the metal-containing coating film 4. This can enhance the uniform orientation of the metal flakes in a direction parallel to the surface layer, rather than uniformly dispersing the metal flakes throughout the metal-containing coating film.

[0024] The metal-containing coating film 4 is formed to a thickness of, for example, 20 μm. In this embodiment, the thickness of the metal-containing coating film 4 is greater than the thickness of the primer film 3. Specifically, the thickness of the metal-containing coating film 4 is at least twice the thickness of the primer film 3. In a metal-containing coating film 4 having a thickness greater than that of the primer film 3, for example, the layer formed by densely packed metal flakes is thicker, and the gaps between the metal flakes can be sealed. As a result, the brilliance of the metal-containing coating film 4 can be improved. Furthermore, the metal-containing coating film 4 contains a layer of dried water-soluble resin below the layer formed by densely packed metal flakes (the layer on the primer film 3 side). This layer of water-soluble resin has a thickness greater than that of the layer formed by densely packed metal flakes. This two-layer structure, consisting of a layer formed by densely packed metal flakes and a layer of water-soluble resin, allows the thickness of the metal-containing coating film 4 to be increased while improving the uniform orientation of the metal flakes, compared to conventional methods in which the metal flakes are uniformly dispersed in the metal-containing coating film.

[0025] The increased brilliance of the metal-containing coating film 4 increases the specular reflectance of the metal-containing coating film 4 (i.e., the coating film 10). This reduces the absorptivity of the left roof rail 1A for external light incident on the left roof rail 1A from outside the vehicle. This makes it possible to suppress a rise in temperature of the left roof rail 1A when exposed to sunlight, for example.

[0026] The clear coating film 5 is a transparent protective film that covers the metal-containing coating film 4 from the side opposite the primer film 3. Such a clear coating film 5 can be formed by applying a clear paint so as to overlap the metal-containing coating film 4 and then drying it. For example, the clear paint may be an acrylic clear paint, a urethane clear paint, a silicone clear paint, or a fluorine clear paint. The clear coating film 5 is formed to a thickness of, for example, 20 to 30 μm.

[0027] The roof rail 1 of this embodiment includes a base 2 and a coating film 10. The base 2 is made of resin. The coating film 10 has a metallic luster and covers the surface of the base 2. The coating film 10 also includes a primer film 3 and a metal-containing coating film 4. The primer film 3 is adhered to the surface of the base 2. The metal-containing coating film 4 covers the surface of the base 2 with the primer film 3 sandwiched therebetween. The film thickness of the metal-containing coating film 4 is greater than the film thickness of the primer film 3.

[0028] In the roof rail 1 of this embodiment, the metal-containing coating film 4 is thick and the primer film 3 is thin. The roof rail 1 of this embodiment can prevent external light from entering the primer film 3 through the metal-containing coating film 4. Even if external light reaches the primer film 3, the metal-containing coating film 4 is formed thick, so that the external light reflected by the primer film 3 can be prevented from being emitted to the outside through the metal-containing coating film 4. Therefore, the roof rail 1 of this embodiment can prevent the color tone of the primer film 3 from being visible to outsiders through the metal-containing coating film in the roof rail 1 whose base 2 is made of resin.

[0029] Furthermore, in the roof rail 1 of this embodiment, the film thickness of the metal-containing coating film 4 is at least twice the film thickness of the primer film 3. According to the roof rail 1 of this embodiment, the specular reflectance of the metal-containing coating film 4 can be further improved, and it is possible to prevent the color tone of the primer film 3 from being visible to outsiders and to prevent the base 2 from expanding and contracting due to temperature changes.

[0030] Furthermore, in the roof rail 1 of this embodiment, the coating film 10 covers the metal-containing coating film 4 from the side opposite to the primer film 3, and also has a transparent clear coating film 5. According to the roof rail 1 of this embodiment, the clear coating film 5 can suppress deterioration of the metal-containing coating film 4.

[0031] The specular reflection value of the roof rail 1 of this embodiment was measured using a color meter VC-2 manufactured by Suga Test Instruments Co., Ltd. The specular reflection value is an L value that indicates the brightness of specularly reflected light, and a larger value indicates a higher reflectance and a brighter color. For comparison, measurements were also taken under the same conditions for a roof rail on which a plating film was formed instead of the coating film 10, a roof rail on which a satin-finish plating film was formed instead of the coating film 10, and a roof rail made of aluminum.

[0032] The specular reflectance value of the roof rail 1 of this embodiment was 500. The specular reflectance value of the roof rail on which a plating film was formed was 785. The specular reflectance value of the roof rail on which a satin plating film was formed was 437. The specular reflectance value of the roof rail made of aluminum was 622. These measurement results show that the specular reflectance value of the roof rail 1 of this embodiment is higher than that of the roof rail on which a satin plating film was formed, and is close to that of the roof rail made of aluminum or the roof rail on which a plating film was formed. Therefore, it was found that the roof rail 1 of this embodiment has a metallic luster similar to that of a plating film or aluminum.

[0033] In the coating film 10 of the roof rail 1 of this embodiment, the thickness of the primer film 3 is 5 to 10 μm, the thickness of the metal-containing coating film 4 is 20 μm, and the thickness of the clear coating film 5 is 20 to 30 μm. In other words, the above measurement results show that by setting the thicknesses of the primer film 3, the metal-containing coating film 4, and the clear coating film 5 within the above ranges, the roof rail has a good metallic luster.

[0034] Furthermore, in the roof rail 1 of this embodiment, the base 2 has an outer surface 2a that is a surface facing the outside of the vehicle 100. Furthermore, the coating film 10 is formed so as to cover the outer surface 2a. According to the roof rail 1 of this embodiment, since the coating film 10 is provided on the outer surface 2a, sunlight can be reflected and the temperature of the base 2 can be prevented from rising due to exposure to sunlight.

[0035] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0036] For example, in the above embodiment, an example in which the vehicle exterior part according to the present invention is applied to a roof rail has been described. However, the present invention is not limited to this. The present invention can be applied to any vehicle exterior part that is visible from outside the vehicle.

[0037] 1... roof rail (vehicle exterior part), 1a... main body wall part, 1A... left roof rail (vehicle exterior part), 1b... outer wall surface, 1B... right roof rail (vehicle exterior part), 1c... inner wall surface, 2... base part, 2a... outer surface, 3... primer film, 4... metal-containing coating film, 5... clear coating film (protective film), 10... coating film

Claims

1. A vehicle exterior part comprising a base made of resin and a coating film having a metallic luster and covering the surface of the base, The aforementioned coating film is A primer film adhered to the surface of the base, A metal-containing coating film covering the surface of the base with the primer film sandwiched in between, It has, The thickness of the metal-containing coating is greater than the thickness of the primer film. Vehicle exterior parts.

2. The thickness of the metal-containing coating is at least twice the thickness of the primer film. Vehicle exterior part according to claim 1.

3. The coating film covers the metal-containing coating film from the side opposite to the primer film and has a transparent protective film. Vehicle exterior part according to claim 1 or 2.

4. The thickness of the primer film is 5 to 10 μm. The thickness of the metal-containing coating is 20 μm. The thickness of the protective film is 20 to 30 μm. Vehicle exterior part according to claim 3.

5. A roof rail comprising the vehicle exterior component according to claim 1 or 2.

6. The surface of the base is an outer surface facing outwards from the vehicle. The coating film is formed to cover the outer surface, The roof rail according to claim 5.