JP2022155657A - Exterior part for vehicle - Google Patents

Abstract

To provide an exterior part for a vehicle which includes metallic sheen and at the same time is capable of enhancing electric wave permeability rather than when using indium.SOLUTION: A radar cover 10 has an electric wave permeability and comprises a stem 12a made of a resin having the electric wave permeability and a silver film layer 12c which is supported by the stem 12a and includes a plurality of circular fine openings.SELECTED DRAWING: Figure 3

Description

The present invention relates to vehicle exterior parts.

In recent years, vehicles are equipped with radar units that detect obstacles and the like around the vehicle using radio waves such as millimeter waves. Such a radar unit is generally arranged in a state where it is covered with a vehicle exterior component such as a radar cover having radio wave transparency so as not to be visually recognized by people outside the vehicle.

By the way, since the vehicle exterior parts are visible from the outside, they greatly affect the external impression of the vehicle. For this reason, it is necessary for the vehicle exterior parts to enhance the designability while ensuring the permeability of electromagnetic waves. For example, Patent Literature 1 describes a vehicle cover member provided with a thin film made of indium through which electromagnetic waves can pass, thereby imparting metallic luster.

JP-A-2000-49522

A thin film made of indium can be formed by vacuum deposition or sputtering to form a sea-island structure in which gaps are formed between a large number of island portions made of indium. With such a sea-island structure, electromagnetic waves can pass through the gaps between the islands, and the thin film made of indium has electromagnetic wave permeability. However, the indium gaps formed by vacuum deposition or sputtering are linear and have a very small width dimension of about several nanometers. For this reason, many components of electromagnetic waves cannot pass through the indium thin film, and there is a limit to the transmittance of radio waves in the indium thin film.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle exterior component that has a metallic luster and is capable of improving radio wave transmittance compared to the case of using indium.

The present invention employs the following configurations as means for solving the above problems.

A first aspect of the present invention is a radio-wave-transmitting vehicle exterior component, which includes a radio-wave-transmitting resin base material and a plurality of circular fine openings supported by the base material. and a silver film layer.

According to a second aspect of the present invention, in the first aspect, the minute openings having a diameter of 10 μm or more are provided in the silver film layer.

According to a third aspect of the present invention, in the first or second aspect, the thickness dimension of the silver film layer is from 15 nm to 40 nm.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a protective coating layer having transparency and radio wave permeability and covering the silver film layer from the side opposite to the base material is provided. adopt.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a base coat layer having radio wave permeability and interposed between the base material and the silver film layer is provided. adopt.

In the present invention, a silver film layer supported by a radio wave transmitting resin substrate is provided. Therefore, the vehicle exterior component of the present invention has a metallic luster obtained by reflecting light on the silver film layer. Further, the silver film layer is provided with a plurality of fine circular openings. These fine openings are not linear gaps seen in a sea-island structure formed by an indium thin film, but circular openings that can secure a large area. Therefore, according to the present invention, it is possible to secure a wide radio wave transmittable region in the silver film layer. Therefore, according to the present invention, it is possible to improve the radio wave transmittance as compared with the case of using indium while having a metallic luster in the vehicle exterior component.

1 is a front view of a radiator grill with a radar cover in one embodiment of the invention; FIG. 1 is an enlarged front view of a radar cover in one embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS (a) is typical sectional drawing of the radar cover of one Embodiment of this invention, (b) is typical sectional drawing of the inner core with which the radar cover of one Embodiment of this invention is provided. It is an expansion schematic diagram of the silver film layer with which the radar cover in one Embodiment of this invention is provided, (a) is a top view, (b) is sectional drawing. It is a schematic diagram for demonstrating the manufacturing process of the radar cover of one Embodiment of this invention. It is a surface enlarged photograph of the silver film layer with which the radar cover of one Embodiment of this invention is provided. It is a surface enlarged photograph of the silver film layer with which the radar cover of one Embodiment of this invention is equipped. FIG. 5 is a front view of a radiator grille that is a modified example of the present invention;

An embodiment of a vehicle exterior component according to the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a radiator grille 1 having a radar cover 10 (vehicle exterior component) according to the present embodiment. FIG. 2 is an enlarged front view of the radar cover 10 of this embodiment. 3A is a schematic cross-sectional view of the radar cover 10 of this embodiment, and FIG. 3B is a schematic cross-sectional view of the inner core 12 included in the radar cover 10 of this embodiment.

A radiator grille 1 is provided in the front of the vehicle so as to block an opening leading to the engine room of the vehicle, ensuring ventilation to the engine room and preventing foreign matter from entering the engine room. A radar cover 10 is provided in the center of the radiator grille 1 so as to face the radar unit R arranged in the engine room. The radiator grille 1 except for the radar cover 10 is plated with chromium (Cr), for example, because it is not necessary to have radio wave transparency.

The radar unit R (see FIG. 3(a)) has, for example, a transmitter that transmits millimeter waves, a receiver that receives reflected waves, a calculator that performs arithmetic processing, and the like. The radar unit R transmits and receives radio waves that pass through the radar cover 10, and detects the surrounding conditions of the vehicle based on the received radio waves. For example, the radar unit R calculates and outputs the distance to the obstacle, the relative speed of the obstacle, and the like.

The radar cover 10 is arranged to cover the radar unit R when viewed from the front side of the vehicle. As shown in FIG. 2, the radar cover 10 includes a bright region 10A representing figures, characters, etc., representing an emblem of the vehicle manufacturer, and a black region improving visibility of the bright region 10A when viewed from the front side of the vehicle. 10B. Such a radar cover 10 includes a transparent member 11, an inner core 12, and a base member 13 (back member), as shown in FIG. 3(a).

The transparent member 11 is a portion formed of a substantially rectangular transparent material that is arranged on the outermost side of the vehicle. The transparent member 11 has a smooth front surface in order to enhance the visibility of the inner core 12 from the outside of the vehicle. In addition, a concave portion 11 a in which the inner core 12 is arranged is formed on the back surface of the transparent member 11 . A region of the back surface of the transparent member 11 where the concave portion 11a is not provided serves as a fixing surface with the base member 13 .

The recessed portion 11a is a portion that accommodates the inner core 12, and allows the accommodated inner core 12 to be viewed three-dimensionally from the front side of the vehicle. This concave portion 11a is provided along the shape of figures such as an emblem of a vehicle maker, characters, or the like. By accommodating the inner core 12 in such a concave portion 11a, the bright region 10A described above is formed.

Such a transparent member 11 has a body portion 15 provided with a concave portion 11a and a hard coat layer 16 provided on the surface of the body portion 15 to form the smooth surface described above. The main body 15 is made of a transparent synthetic resin such as colored and transparent PC (polycarbonate) or PMMA (polymethyl methacrylate resin), and has a thickness of about 1.5 mm to 10 mm. The hard coat layer 16 is a transparent coating layer that covers the surface of the body portion 15 . The hard coat layer 16 prevents the surface of the body portion 15 from being damaged.

As shown in FIG. 3B, the inner core 12 includes a base portion 12a (base material), a base coat layer 12b, a silver film layer 12c, and a top coat layer 12d (protective coat layer). The base portion 12a is a resin member having radio wave transparency, and is formed by injection molding. The base portion 12a is made of a synthetic resin having radio wave transparency such as ABS, PC, or PET. The base portion 12a has a convex shape that embeds the concave portion 11a of the transparent member 11, and is fitted into the concave portion 11a of the transparent member 11. As shown in FIG.

The base coat layer 12b has radio wave transparency and is interposed between the base portion 12a and the silver film layer 12c. This base coat layer 12b improves the adhesion between the base portion 12a and the silver film layer 12c. The base coat layer 12b is formed, for example, by clear coating using a transparent synthetic resin.

The silver film layer 12c is formed on the surface of the front side of the base portion 12a (the surface on the side of the transparent member 11), is arranged so as to cover the base portion 12a and is supported, and is a layer having metallic luster. This silver film layer 12c is a thin film made of silver (Ag). A metallic luster is obtained by reflecting light on such a silver film layer 12c.

FIG. 4 is an enlarged schematic diagram of the silver film layer 12c, where (a) is a plan view and (b) is a cross-sectional view. As shown in these figures, the silver film layer 12c has a plurality of fine openings 12c1. The fine opening 12c1 is an opening that penetrates the silver film layer 12c and exposes the base portion 12a through the base coat layer 12b. Each fine opening 12c1 is circular in plan view and has various diameters. At least some of the fine openings 12c1 are preferably formed to have a diameter of 10 μm or more.

In addition, as shown in FIG. 4A, the plan view shape of the fine opening 12c1 is not necessarily a perfect circle. For this reason, the diameter dimension can be, for example, the diameter dimension of the smallest perfect circle that the fine opening 12c1 can inscribe without protruding. Also, the thickness dimension of the silver film layer 12c can be, for example, 15 nm to 40 nm.

When an indium (In) film is formed by vacuum deposition or sputtering, a structure (sea-island structure) having a plurality of island portions arranged with gaps therebetween is formed. Numerous fine linear gaps formed between a plurality of islands in the sea-island structure are regions that are transparent to radio waves such as millimeter waves. These fine linear gaps are formed continuously and have a width dimension of about several nanometers. That is, when an indium (In) film is formed by vacuum deposition or sputtering, the radio wave transmission region becomes a linear gap with a width dimension of about several nanometers.

On the other hand, in the radar cover 10 of the present embodiment, the silver film layer 12c provided with a plurality of fine openings 12c1 having a diameter of 10 μm or more is provided as a bright film. These fine openings 12c1 serve as transmission regions for radio waves. Therefore, compared with the case where a thin film of indium (In) is provided as the photoluminescent film, the area through which radio waves can pass is expanded. Therefore, the silver film layer 12c in the radar cover 10 of this embodiment becomes a bright film with high radio wave transmittance.

Returning to FIG. 3, the topcoat layer 12d is formed on the silver film layer 12c so as to cover the silver film layer 12c, and is a transparent layer that protects the silver film layer 12c. The top coat layer 12d is formed by clear coating using a transparent (including colored transparent) synthetic resin, for example. The top coat layer 12d can also be a transparent ceramic coat layer made of silicon oxide (SiOx). In this case, as compared with a topcoat layer made of a resin formed by clear coating or the like, the topcoat layer has high heat resistance and high radio wave transmittance.

In addition, the topcoat layer 12d is formed so as to enter the fine openings 12c1 of the silver film layer 12c. That is, the topcoat layer 12d is connected to the basecoat layer 12b through the fine openings 12c1. Therefore, the silver film layer 12c is sandwiched between the top coat layer 12d and the base coat layer 12b firmly fixed to the base portion 12a, and the adhesion of the silver film layer 12c is improved.

The base member 13 is a portion fixed to the back side of the transparent member 11, and is made of a black resin material. The base member 13 has an engaging portion 13a projecting toward the engine room. The engaging portion 13a has a claw-shaped tip, and the tip is engaged with, for example, a radiator grill body. The base member 13 fixed to the back surface of the transparent member 11 in this manner is visible from the outside of the transparent member 11, and forms the above-described black region 10B. The base member 13 makes the area other than the bright area 10A appear black and relatively improves the visibility of the bright area 10A.

Such a base member 13 is composed of ABS (acrylonitrile-butadiene-styrene copolymer synthetic resin), AES (acrylonitrile-ethylene-styrene copolymer synthetic resin), ASA (acrylonitrile-styrene-acrylate), PBT (polybutylene terephthalate), It is made of synthetic resin such as colored PC or PET (polyethylene terephthalate), or a composite resin of these, and has a thickness of about 0.5 mm to 10 mm.

Next, a method for manufacturing the radar cover 10 of this embodiment will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the manufacturing method of the radar cover 10 of this embodiment. First, as shown in FIG. 5A, the main body 15 of the transparent member 11 is formed. For example, the transparent member 11 is formed by injection molding a resin material. By this injection molding, it is possible to form the main body portion 15 having the concave portion 11a, so there is no need to form the concave portion 11a in a post-process.

Subsequently, as shown in FIG. 5B, a hard coat layer 16 is formed on the front surface side (the surface facing the outside of the vehicle) of the main body 15 to improve durability and the like. Here, for example, the hard coat layer 16 is formed by applying a material for forming the hard coat layer to the surface of the body portion 15 and drying the material.

Next, as shown in FIG. 5(c), the base portion 12a of the inner core 12 is formed. For example, the base 12a is formed by injection molding. Subsequently, as shown in FIG. 5(d), a basecoat layer 12b, a silver film layer 12c and a topcoat layer 12d are formed. For example, the base coat layer 12b is formed by applying clear coating to the base 12a and then drying it. Further, the silver film layer 12c is formed on the basecoat layer 12b by applying the material for forming the silver film layer 12c onto the basecoat layer 12b and drying the material. Also, the surface of the silver film layer 12c is coated with a clear coating, and then dried to form the topcoat layer 12d. It is not necessary to form the inner core 12 after forming the transparent member 11 shown in FIGS. 5(a) and 5(b). By forming the inner core 12 in parallel with the process of forming the transparent member 11 shown in FIGS. 5A and 5B, the manufacturing time of the radar cover 10 can be shortened.

The material for forming the silver film layer 12c is not particularly limited, but for example, an alcohol solution in which a polymer dispersant is dissolved in an alcohol solvent and a silver compound is dispersed can be used. For example, as the polymer dispersing agent, an acid having a styrene-maleic anhydride resin structure, in which part of the maleic anhydride is modified with a polyalkylene glycol having a terminal hydroxyl group or a polyalkylene glycol having a terminal amino group. Those having a value of 150 or less can be used. As alcohol solvents, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol and 1-methoxy-2-propanol can be used. Polyalkylene glycol having a molar ratio of polyethylene glycol chains and polypropylene glycol chains of 6/4 to 8/1 and having a molecular weight of 500 to 3,000 can be used.

The thickness dimension of the silver film layer 12c and the size and density of the fine openings 12c1 can be adjusted by adjusting the concentration of the silver compound in the material forming the silver film layer 12c and the number of applications of the material forming the silver film layer 12c. It is possible.

Next, as shown in FIG. 5(e), the inner core 12 is fitted into the concave portion 11a of the transparent member 11. Then, as shown in FIG. Next, as shown in FIG. 5(f), the base member 13 is formed. Here, the transparent member 11 having the inner core 12 installed in the concave portion 11a is placed inside a mold for injection molding, and insert molding is performed by injecting a molten resin into the back side of the transparent member 11 to form a base. A member 13 is formed. Such a base member 13 is welded to the transparent member 11 by heat during insert molding, and arranged so as to cover the inner core 12 . As a result, the inner core 12 is fixed in contact with the transparent member 11 .

The radar cover 10 of the present embodiment is manufactured through the steps described above. The radar cover 10 of this embodiment is a radar cover 10 having radio wave permeability, and is supported by a base portion 12a made of resin having radio wave permeability and a circular minute opening 12c1 supported by the base portion 12a. and a plurality of silver film layers 12c.

The radar cover 10 of this embodiment has a silver film layer 12c supported by a resin base portion 12a having radio wave transparency. Therefore, the radar cover 10 of this embodiment has a metallic luster obtained by reflecting light on the silver film layer 12c. Further, the silver film layer 12c is provided with a plurality of circular fine openings 12c1. These fine openings 12c1 are not linear gaps seen in a sea-island structure formed of an indium (In) thin film, but are circular openings that can secure a large area. Therefore, according to the radar cover 10 of the present embodiment, it is possible to secure a wide radio wave transmittable region in the silver film layer 12c. Therefore, according to the radar cover 10 of the present embodiment, it has a metallic luster and can improve the radio wave transmittance more than in the case of using indium (In).

Further, in the radar cover 10 of the present embodiment, fine openings 12c1 having a diameter of 10 μm or more are provided in the silver film layer 12c. According to the radar cover 10 of this embodiment, since the fine openings 12c1 having a diameter of 10 μm or more that can ensure a wide opening area are provided in the silver film layer 12c, it is possible to further improve the radio wave transmittance. becomes.

Further, in the radar cover 10 of the present embodiment, by setting the thickness dimension of the silver film layer 12c to 15 nm or more and 40 nm or less as described later, it is possible to reliably provide the fine openings 12c1 in the silver film layer 12c. becomes.

Further, the radar cover 10 of the present embodiment is provided with a top coat layer 12d that is transparent and has radio wave permeability and covers the silver film layer 12c from the side opposite to the base portion 12a. Therefore, according to the radar cover 10 of the present embodiment, the metallic luster of the silver film layer 12c can be visually recognized through the topcoat layer 12d. Moreover, it becomes possible to protect the silver film layer 12c by the top coat layer 12d.

Further, the radar cover 10 of the present embodiment includes a base coat layer 12b having radio wave transparency and interposed between the base portion 12a and the silver film layer 12c. Therefore, it is possible to improve the adhesion of the silver film layer 12c to the underlying layer.

Further, the radar cover 10 of the present embodiment includes the silver film layer 12c formed by drying an alcohol solution containing a silver compound. 12c is sandwiched between them, it becomes an exterior component for a vehicle with high weather resistance and high practicality. For example, in general silver mirror coating, a corrosion prevention layer is interposed between the metal film and the topcoat layer, and a surface conditioner layer is interposed between the metal film and the basecoat layer. Therefore, in the radar cover 10 of the present embodiment, it is possible to simplify the layer structure for maintaining the brilliance as compared with the general silver mirror coating.

6 and 7 are enlarged photographs of the surface of the silver film layer 12c, showing how the surface of the silver film layer 12c changes when the thickness dimension is changed. In FIGS. 6 and 7, the length of the long side of one square of the lattice is 400 μm. In addition, in FIGS. 6 and 7, the portion shown in black is the fine opening 12c1.

FIG. 6A is an optical microscope photograph showing the appearance of the surface of the silver film layer 12c having a thickness of 15 nm. FIG. 6B is an optical microscope photograph showing the surface of the silver film layer 12c having a thickness of 20 nm. FIG. 6C is an optical microscope photograph showing the surface of the silver film layer 12c having a thickness of 23.2 nm. FIG. 7D is an optical microscope photograph showing the surface of the silver film layer 12c having a thickness of 35 nm. FIG. 7(e) is an optical microscope photograph showing the appearance of the surface of the silver film layer 12c having a thickness of 38.3 nm.

As is clear from these photographs, when the thickness dimension of the silver film layer 12c is 15 nm to 38.3 nm, the fine apertures 12c1 are formed although the density and size of the fine apertures 12c1 vary. I found out. From this result, it is considered that the fine opening 12c1 is formed when the thickness dimension of the silver film layer 12c is at least 15 nm or more and 40 nm or less.

As a result of color measurement of the silver film layer 12c having a film thickness of 15 nm shown in FIG. 6A, the L value was 41.04 and the b value was 2.28. As a result of color measurement of the silver film layer 12c having a film thickness of 20 nm shown in FIG. 6B, the L value was 46.17 and the b value was 0.75. As a result of color measurement of the silver film layer 12c having a thickness of 23.3 nm shown in FIG. 6(c), the L value was 52.52 and the b value was −0.10. As a result of color measurement of the silver film layer 12c having a film thickness of 35 nm shown in FIG. 7D, the L value was 53.48 and the b value was 0.21. Further, as a result of color measurement of the silver film layer 12c having a film thickness of 38.3 nm shown in FIG. 7E, the L value was 54.90 and the b value was 0.37.

From these colorimetry results, it was found that when the thickness dimension of the silver film layer 12c is 15 nm to 38.3 nm, a metallic luster equivalent to jet black plating can be obtained.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiments. The various shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

For example, in the above embodiment, an example in which the vehicle exterior component of the present invention is applied to the radar cover 10 has been described. However, the invention is not limited to this. FIG. 8 is a front view of the radiator grill 1A without the radar cover 10. FIG. It is also possible to apply the present invention to such a radiator grill 1A. In this case, for example, the radiator grille 1A as a whole or a portion that transmits radio waves is made of a radio wave transmitting resin substrate and a silver film layer supported by the substrate and having a plurality of circular fine openings. and.

Further, in the above-described embodiment, an example in which the present invention is applied to the radar cover including the transparent member 11, the inner core 12, and the base member 13 has been described. However, the invention is not limited to this. For example, the present invention can be applied to a radar cover in which the silver film layer 12c is formed on the transparent member 11 and the base portion 12a of the inner core 12 and the like are integrated with the base member 13. FIG.

Reference Signs List 1 Radiator grill 1A Radiator grill (vehicle exterior component) 10 Radar cover (vehicle exterior component) 10A Bright area 10B Black area 11 Transparent member 11a ... concave part 12... inner core 12a... base part 12b... base coat layer 12c... silver film layer 12d... top coat layer (protective coat layer) 13... base member 13a... engaging portion

Claims (5)

A vehicle exterior component having radio wave transparency,
a base material made of resin having radio wave transparency;
and a silver film layer supported by the substrate and having a plurality of circular fine openings. 2. The vehicle exterior component according to claim 1, wherein said fine openings having a diameter of 10 [mu]m or more are provided in said silver film layer. 3. The vehicle exterior component according to claim 1, wherein said silver film layer has a thickness of 15 nm or more and 40 nm or less. The vehicle exterior component according to any one of claims 1 to 3, further comprising a protective coating layer that is transparent and has radio wave permeability and covers the silver film layer from the side opposite to the base material. The vehicle exterior component according to any one of claims 1 to 4, further comprising a base coat layer having radio wave transparency and interposed between the base material and the silver film layer.

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