Infrared transparent bright coating film and infrared transparent cover

Abstract

An infrared-transmitting glossy coating (12) comprises an infrared-transmitting base resin (21) and a filler (22) added to the base resin (21). The filler (22) has an aluminum sheet (23) and an infrared-transmitting resin film (24) covering both sides of the sheet (23) in the thickness direction. The thickness of the resin film (24) is greater than the thickness of the sheet (23). The average particle size of the filler (22) is 10 μm or more and 120 μm or less. The weight concentration of the filler (22) is 0.1% or more and 1.0% or less. The area fraction of the filler (22) is 0.5% or more and 1.5% or less.

Description

Technical Field

[0001] This disclosure relates to a glossy coating with infrared transmittance and an infrared transmittance cover. Background Technology

[0002] Patent Document 1 discloses an infrared-transmitting product. This infrared-transmitting product, for example, includes a main body that covers the rear of an infrared sensor disposed on the front grille of a vehicle. The main body has a transparent substrate and a coating layer formed on the back of the transparent substrate. Both the transparent substrate and the coating layer are infrared-transmitting. The transparent substrate is formed of a resin material such as polycarbonate. The coating layer has a transparent resin such as epoxy resin and aggregates dispersed within the transparent resin. The aggregates are formed by the aggregation of particles of various pigments. As pigments, titanium dioxide, etc., is used on the surface of the particles to diffuse light and thus appear white.

[0003] Such infrared-transmitting products have both infrared transmittance and visible light reflectivity.

[0004] In the past, encapsulated components in vehicles sometimes included a metallic coating consisting of a transparent base resin and fillers added to the base resin. In such encapsulated components, visible light was reflected by the aluminum flakes constituting the fillers, thereby creating a shimmering metallic sheen.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-56346 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The desired outcome is a glossy coating and an infrared transmissive cover that exhibit both high infrared transmittance and metallic infrared transmittance.

[0010] Methods for solving problems

[0011] The infrared-transmitting glossy coating for solving the above-mentioned problems comprises an infrared-transmitting base resin and a filler added to the base resin. The filler has an aluminum sheet and an infrared-transmitting resin film covering both sides of the sheet in the thickness direction. The thickness of the resin film is greater than the thickness of the sheet. The particle size of the filler is 10 μm to 120 μm, the weight concentration of the filler is 0.1% to 1.0%, and the area occupancy of the filler is 0.5% to 1.5%.

[0012] To achieve a metallic tone in the coating, aluminum flake monomers can be used as fillers added to the base resin. In this case, the more filler is added, the more easily the flakes adhere to each other, resulting in fewer gaps for infrared transmission and easier reflection of infrared light. Consequently, the infrared transmittance decreases.

[0013] On the other hand, the lower the amount of filler, the higher the infrared transmittance. However, since visible light is difficult to reflect by the thin sheet, a metallic tone cannot be observed.

[0014] In this respect, according to the above configuration, since the thickness of the resin film is greater than the thickness of the flakes, it is possible to prevent the spacing between the flakes within the base resin from becoming too small. Furthermore, according to the above configuration, by setting the filler particle size, filler weight concentration, and filler area occupancy, the light transmittance of the glossy coating in both the first wavelength band (880nm to 930nm) and the second wavelength band (1540nm to 1560nm) is 70% to 92% to 1560%. Additionally, the glossy coating has a particle appearance (G-value) of 5 to 30. It should be noted that a higher particle appearance (G-value) results in a higher glossiness.

[0015] Therefore, it can exhibit a metallic tone while having high infrared transmittance in both wavelength bands of the infrared radar device.

[0016] In the above-mentioned infrared-transmitting glossy coating, preferably, the thickness of the filler is 1 μm or more and 3 μm or less, and the thickness of the sheet is 20 nm or more and 100 nm or less.

[0017] According to this configuration, the spacing between the sheets within the base resin can be sufficiently suppressed from becoming too small, thereby improving the light transmittance in both wavelength bands of the infrared radar device. Furthermore, the thickness of the sheets used to enhance the shimmering effect can be adequately ensured.

[0018] In the above-mentioned bright coating with infrared transmittance, it is preferable to have a thickness of 5 μm or more and 50 μm or less.

[0019] When the thickness of a glossy coating is less than 5 μm, the particle appearance is likely to be less than 5, making it difficult to improve the glossiness. On the other hand, when the thickness of a glossy coating is greater than 50 μm, the light transmittance is likely to be less than 70%.

[0020] In this respect, based on the above configuration, since the glossy coating has a thickness of 5μm to 50μm, the aforementioned adverse conditions can be suppressed. Therefore, it is possible to more reliably improve the light transmittance in both wavelength bands of the infrared radar device while exhibiting a metallic effect.

[0021] An infrared transmittance cover for solving the above-mentioned problems includes: an infrared-transmitting transparent substrate, an infrared-transmitting glossy coating film disposed on the transparent substrate, and a visible light blocking layer disposed on the glossy coating film on the side opposite to the transparent substrate and blocking visible light from passing through.

[0022] Based on this structure, it can achieve the same effect as the aforementioned glossy coatings with infrared transmittance. Attached Figure Description

[0023] [ Figure 1 ] Figure 1 This is a cross-sectional view of a cover according to one embodiment.

[0024] [ Figure 2 ] Figure 2 It constitutes Figure 1 A cross-sectional view of the filler in the glossy coating.

[0025] [ Figure 3 ] Figure 3 yes Figure 1 A magnified cross-sectional view of the glossy coating. Detailed Implementation

[0026] The following is for reference Figures 1-3 An embodiment of an infrared-transmitting cover and an infrared-transmitting glossy coating will be described.

[0027] like Figure 1 As shown, an infrared radar device 90 is installed on the vehicle. The infrared radar device 90 transmits infrared IR rays containing wavelengths in a first wavelength band of 880nm to 930nm or a second wavelength band of 1540nm to 1560nm.

[0028] It should be noted that the directions in front and behind the infrared IR transmission direction from the infrared radar device 90 will be described as front and rear respectively below.

[0029] like Figure 1 As shown, an infrared-transmitting cover (hereinafter referred to as cover 10) is installed on the vehicle to cover the infrared radar device 90 from the front.

[0030] The cover 10 includes: an infrared-transmitting transparent substrate 11, an infrared-transmitting glossy coating 12 disposed on the transparent substrate 11, and a visible light blocking layer 13 disposed on the surface of the glossy coating 12 opposite to the transparent substrate 11 and blocking visible light from passing through.

[0031] The transparent substrate 11 is formed of resin materials such as polycarbonate, polymethyl methacrylate, cyclic olefin polymer, and resin glass. In this embodiment, the transparent substrate 11 is formed of polycarbonate.

[0032] like Figure 3 As shown, the glossy coating 12 comprises an infrared-transmitting base resin 21 and a filler 22 added to the base resin 21.

[0033] The glossy coating 12 is formed by applying a coating containing a base resin 21 and filler 22 to the back of a transparent substrate 11. A curing agent may be used with the coating as needed.

[0034] <Basic Resin 21>

[0035] The base resin 21 has at least one component selected from the group consisting of: epoxy resin, silicone resin, urethane, urea resin, phenolic resin, polyethylene, polypropylene, polyethylene terephthalate, vinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer, acrylic resin, polyamide, polyimide, polycarbonate, and melamine resin. It should be noted that "main component" refers to the component that affects the properties of the material, and the content of this component is typically 50% or more by mass of the total material.

[0036] The curing agent can be used appropriately depending on the material of the base resin 21. When using a resin with epoxy resin as the main component as the base resin 21, examples of curing agents include anhydride-based curing agents and phenol-based curing agents. When using a resin with resin other than epoxy resin as the main component as the base resin 21, the curing agent can be omitted.

[0037] In addition to the aforementioned anhydride-based and phenolic-based curing agents, other curing agents may be used as curing agents depending on their purpose and application. Examples of such curing agents include: amine-based curing agents; curing agents formed by partial esterification of the aforementioned anhydride-based curing agents with alcohols; or curing agents containing carboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, and methylhexahydrophthalic acid. These can be used alone or in combination of two or more, and can also be used in combination with the aforementioned anhydride-based and phenolic-based curing agents.

[0038] It should be noted that when using a curing agent, a curing accelerator can also be used in conjunction.

[0039] <Packaging 22>

[0040] like Figure 2 As shown, the filler 22 has an aluminum sheet 23 and an infrared-transmitting resin film 24 on both sides of the sheet 23 in the thickness direction. The resin film 24 is made of, for example, acrylic, urethane, ester, or siloxane resins. It should be noted that the filler 22 can also be colored by adding pigments to the resin film 24.

[0041] The filler 22 has a flat shape. The thickness t2 of the resin film 24 is greater than the thickness t1 of the sheet 23 (t2 > t1).

[0042] The particle size D of packing 22 is between 10 μm and 120 μm. The particle size D of packing 22 is the maximum length of packing 22 in the face direction.

[0043] The thickness t3 of filler 22 is preferably 1 μm or more and 3 μm or less.

[0044] The thickness t1 of the thin film 23 is more than 20nm and less than 100nm.

[0045] In this embodiment, the thickness t3 of the filler 22 is 2 μm (=2000 nm). The thickness t1 of the sheet 23 is 60 nm. The thickness t2 of the resin film 24 is 970 nm. It should be noted that the following equation 1 holds true between the thickness t3 of the filler 22, the thickness t1 of the sheet 23, and the thickness t2 of the resin film 24.

[0046] t3 = t1 + t2 × 2…(Equation 1)

[0047] The filler 22 is formed, for example, as follows: First, a first resin film is formed on a substrate. Then, an aluminum film is formed on the first resin film by vapor deposition. Next, a second resin film is formed on the aluminum film. In this way, a sheet with a three-layer structure is formed. Then, the filler 22 is formed by pulverizing the sheet. In this case, the resin film 24 is only provided on both sides of the sheet 23.

[0048] The weight concentration of filler 22 in the glossy coating 12 is more than 0.1% and less than 1.0%.

[0049] The filler 22 in the glossy coating 12 has an area occupancy of more than 0.5% and less than 1.5%.

[0050] The glossy coating 12 preferably has a thickness t4 of 5 μm or more and 50 μm or less. More preferably, the glossy coating 12 has a thickness t4 of 20 μm or more and 40 μm or less. In this embodiment, the thickness t4 of the glossy coating 12 is 30 μm.

[0051] The visible light cutoff layer 13 is, for example, a known black pressed coating. It should be noted that visible light cutoff pigments can also be added to the black pressed coating.

[0052] Next, the function of this embodiment will be explained.

[0053] like Figure 3As shown by the double-dotted lines, in the glossy coating 12, infrared IR emitted from the infrared radar device 90 passes through the gaps between the fillers 22. Additionally, visible light VL, which passes through the transparent substrate 11 and enters the glossy coating 12, is reflected in front of the sheet 23 of the filler 22. The cover 10 exhibits the black color displayed by the visible light cutoff layer 13. Furthermore, in the cover 10, because the visible light VL is reflected by the sheet 23, it exhibits a shimmering metallic tint.

[0054] Next, the effects of this implementation method will be explained.

[0055] (1) The filler 22 has an aluminum sheet 23 and an infrared-transmitting resin film 24 on both sides of the sheet 23 in the thickness direction. The thickness t2 of the resin film 24 is greater than the thickness t1 of the sheet 23. The particle size D of the filler 22 is 10 μm or more and 120 μm or less. The weight concentration of the filler 22 is 0.1% or more and 1.0% or less. The area occupancy of the filler 22 is 0.5% or more and 1.5% or less.

[0056] With this configuration, since the thickness t2 of the resin film 24 is greater than the thickness t1 of the sheet 23, it is possible to prevent the spacing between the sheets 23 within the base resin 21 from becoming too small. Furthermore, based on the above configuration, by setting the particle size D of the filler 22, the weight concentration of the filler 22, and the area occupancy of the filler 22, the light transmittance of the glossy coating 12 in both the first and second wavelength bands is 70% to 92% or less. Additionally, the glossy coating 12 has a particle appearance (G value) of 5 to 30. It should be noted that a higher particle appearance (G value) results in a higher glossiness. Therefore, it is possible to achieve high infrared transmittance in both wavelength bands of the infrared radar device 90 while exhibiting a metallic tone.

[0057] (2) The thickness t3 of filler 22 is more than 1 μm and less than 3 μm. The thickness t1 of sheet 23 is more than 20 μm and less than 100 μm.

[0058] With this configuration, the spacing between the sheets 23 within the base resin 21 can be sufficiently prevented from becoming too small, thereby improving the light transmittance of the infrared radar device 90 in both wavelength bands. Furthermore, the thickness t1 of the sheets 23 used to enhance the shimmering effect can be adequately ensured.

[0059] (3) The glossy coating 12 has a thickness t4 of more than 5 μm and less than 50 μm.

[0060] When the thickness t4 of the glossy coating 12 is less than 5 μm, the particle appearance, i.e., the G value, tends to be less than 5, making it difficult to improve the shimmer effect. On the other hand, when the thickness t4 of the glossy coating 12 is greater than 50 μm, the light transmittance tends to be less than 70%.

[0061] In this respect, based on the above configuration, since the glossy coating 12 has a thickness t4 of 5 μm to 50 μm, the aforementioned adverse conditions can be suppressed. Therefore, it is possible to more reliably achieve both high infrared transmittance in the two wavelength bands of the infrared radar device 90 and a metallic tone effect.

[0062] (4) The cover 10 includes: an infrared-transmitting transparent substrate 11, a glossy coating 12 disposed on the transparent substrate 11, and a visible light blocking layer 13 disposed on the surface of the glossy coating 12 opposite to the transparent substrate 11 and blocking visible light from passing through.

[0063] Based on this configuration, it can achieve the same effect as the effects (1) to (3) mentioned above.

[0064] <Variation Example>

[0065] This implementation method can be modified as follows. This implementation method and the following modifications can be combined and implemented within the scope of technical inconsistency.

[0066] In addition to covering both sides of the sheet 23, the resin film 24 can also cover the periphery of the sheet 23. That is, the filler 22 can also be covered by the resin film 24 over the entire sheet 23.

[0067] The thickness t4 of the glossy coating 12 can be less than 5 μm or greater than 50 μm.

[0068] The thickness t3 of filler 22 can be less than 1 μm or greater than 3 μm.

[0069] The thickness t1 of the thin film 23 can be less than 20 nm or greater than 100 nm.

Claims

1. An infrared-transmitting glossy coating film, comprising an infrared-transmitting base resin and fillers added to the base resin. The filler comprises aluminum sheets and an infrared-transmitting resin film covering both sides of the sheets in the thickness direction. The thickness of the resin film is greater than the thickness of the sheet. The particle size of the filler is between 10 μm and 120 μm. The weight concentration of the filler is between 0.1% and 1.0%. The area occupancy of the filler is between 0.5% and 1.5%. It has a thickness of 5μm to 50μm.

2. The infrared-transmitting glossy coating according to claim 1, wherein, The thickness of the filler is more than 1 μm and less than 3 μm. The thickness of the thin film is between 20 nm and 100 nm.

3. An infrared-transmitting cover, comprising: Transparent substrate with infrared transmittance The infrared-transmitting glossy coating of claim 1 or claim 2, disposed on the transparent substrate, and A visible light cutoff layer is disposed on the surface of the glossy coating opposite to the transparent substrate and prevents visible light from passing through.

Images