Laminate, decorative device, millimeter wave radar device, and sensor device

Abstract

Provided are a laminate having a metal tone and colorfulness, a decorative device, a millimeter wave radar device, and a sensor device.　The laminate includes a colored clear coat layer, a base material, and a silver mirror layer in this order.

Description

Laminate, decorating device, millimeter wave radar device, and sensor device

[0001] The present disclosure relates to a laminate, a decorating device, a millimeter-wave radar device, and a sensor device.

[0002] The surface of a molded product may be decorated with a metallic finish from a design perspective. Metallic decoration methods include electrolytic plating, vacuum deposition, and hot stamping. Electrolytic plating is widely used to decorate vehicle parts such as bumpers and emblems. For example, a method has been disclosed in which a nickel layer is formed on the surface of a part by electrolytic plating, and then a chromium layer is formed thereon (see, for example, Patent Document 1). There is a demand for adding various designs to these metallic parts. An example of such a design is a metallic finish with color.

[0003] JP 2016-216783 A

[0004] Metal plating layers commonly used for metallic decoration are formed by immersing a substrate in a plating bath, resulting in the formation of a metal plating layer that covers the entire substrate surface. If another layer is provided on the metal plating layer, the other layer is likely to peel off from the metal plating layer. Therefore, it is not possible to provide a color layer on the metal plating layer, and it is not possible to add color to the metallic tone. The present disclosure has been made in consideration of the above circumstances, and aims to provide a laminate, a decoration device, a millimeter-wave radar device, and a sensor device that have a metallic tone and color.

[0005] Specific means for achieving the above object are as follows: <1> A laminate comprising a colored clear coat layer, a substrate, and a silver mirror layer in this order. <2> A laminate having a surface resistivity of 10 ４The laminate according to <1>, having a spectral transmittance of Ω / □ or more. <3> The laminate according to <1> or <2>, wherein the laminate excluding the tinted clear coat layer has a spectral transmittance of 1% or more at a wavelength of 400 nm. <4> The laminate according to any one of <1> to <3>, wherein the laminate excluding the tinted clear coat layer has a spectral transmittance of 0.05% or more at wavelengths from 500 nm to 600 nm. <5> The laminate according to any one of <1> to <4>, wherein the laminate excluding the tinted clear coat layer has a spectral transmittance of 1% or more at a wavelength of 700 nm. <6> The laminate according to any one of <1> to <5>, having a spectral transmittance of 5% or more at a wavelength of 800 nm. <7> The laminate according to any one of <1> to <5>, wherein the laminate is gold in color and has an L ＊ a ＊ b ＊ L in color system ＊ <1> The laminate according to any one of <1> to <6>, wherein the refractive index is 70.0 or more. <8> The laminate according to any one of <1> to <7>, which is a sensor cover or an automobile emblem. <9> A decoration device comprising the laminate according to any one of <1> to <8> and a light source arranged on the silver mirror layer side. <10> A millimeter-wave radar device comprising the laminate according to any one of <1> to <8> and a millimeter-wave radar transceiver arranged on the silver mirror layer side. <11> A sensor device comprising the laminate according to any one of <1> to <8> and a sensor arranged on the silver mirror layer side.

[0006] According to the present disclosure, a laminate having a metallic color, a decorating device, a millimeter-wave radar device, and a sensor device are provided.

[0007] 1 is a schematic cross-sectional view showing an example of a laminate according to the present disclosure;

[0008] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0009] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, particles corresponding to each component may include multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, the terms "layer" and "film" include cases where the layer or film is formed over the entire area when the area in which the layer or film is present is observed, as well as cases where the layer or film is formed over only a portion of the area.

[0010] When describing embodiments with reference to the drawings in this disclosure, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of components in each drawing are conceptual, and the relative size relationships between components are not limited to these. In this disclosure, the side on which the colored clear coat layer is provided is also referred to as the design surface, and the side opposite the design surface is also referred to as the back surface.

[0011] <Laminate> The laminate of the present disclosure comprises, in this order, a tinted clear coat layer, a substrate, and a silver mirror layer. The laminate of the present disclosure has a metallic tone and color. The reason for this is presumed to be as follows: The silver mirror layer formed by the silver mirror reaction is provided on the side of the substrate opposite to the side on which the tinted clear coat layer is provided. Excellent adhesion between the substrate and the tinted clear coat layer prevents peeling of the tinted clear coat layer. The tinted clear coat layer does not easily interfere with the metallic tone of the underlying silver mirror layer, so when observed from the design surface side, the metallic tone of the silver mirror layer and the color of the tinted clear coat layer appear to be combined.

[0012] The silver mirror layer has a sea-island structure in which silver particles are scattered like islands. This structure allows infrared light, visible light, and millimeter waves to pass through the gaps between the silver particles. Therefore, by placing a backlight on the backside, it is possible to make it glow. For example, if the backlight is white, it will glow with the color of the tinted clear coat layer, and if the backlight is colored, it will glow as a mixture of the color of the backlight and the color of the tinted clear coat layer. The laminate of the present disclosure can also be used as an automobile emblem with a millimeter-wave radar transceiver on the backside. The laminate of the present disclosure can also be used as a sensor cover with at least one sensor selected from the group consisting of a millimeter-wave sensor and an infrared sensor on the backside.

[0013] In the present disclosure, millimeter wave transparency refers to the property of transmitting radio waves of frequencies between 20 GHz and 300 GHz that are generally used in millimeter wave radar transmitters and receivers or millimeter wave sensors. ＊ a ＊ b ＊ L in color system ＊ This means that the value is 40 or more.

[0014] Each member used in the present disclosure will be described below.

[0015] - Substrate - The material of the substrate is not particularly limited, and inorganic materials such as glass, organic materials such as resins, etc. Examples of resins include thermosetting resins and thermoplastic resins.

[0016] Examples of thermoplastic resins include polyethylene, polypropylene, polycarbonate, polystyrene, polyvinyl chloride, vinyl polymers, polyester, polyamide, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), polyester, thermoplastic elastomer, and acrylic resin. These resins may be used alone or in combination of two or more. An example of a combination of two or more resins is polycarbonate / ABS resin.

[0017] Examples of the thermosetting resin include silicone resin, polyurethane resin, polyester resin, melamine resin, epoxy resin, phenol resin, urea resin, etc. These resins may be used alone or in combination of two or more.

[0018] When used for sensor covers for motion sensors, etc., preferred substrate materials include polypropylene, polycarbonate, ABS resin, polycarbonate / ABS, and acrylic resin. Polypropylene has a low specific gravity among resins, is easy to process, has high tensile strength, impact strength, and compressive strength, and is also excellent in weather resistance and heat resistance. ABS resin is relatively easy to apply surface treatments to, among plastic materials, and therefore is a resin that is easy to paint after molding the substrate. It also has excellent chemical resistance and rigidity, as well as excellent impact resistance, heat resistance, and cold resistance. Polycarbonate has high impact resistance among plastic materials, excellent weather resistance and heat resistance, and excellent transparency. Polycarbonate is also easy to process, and is a relatively light and durable material among plastic materials.

[0019] The thickness of the substrate can be appropriately designed depending on the application, and the shape of the substrate is not particularly limited.

[0020] In order to improve adhesion between the substrate and the silver mirror layer and to smooth the substrate surface, an undercoat layer may be provided on the side of the substrate on which the silver mirror layer is to be formed. The material for the undercoat layer is not particularly limited and can be selected depending on the purpose of the undercoat layer. For example, fluororesin, polyester resin, epoxy resin, melamine resin, silicone resin, acrylic silicone resin, acrylic urethane resin, etc. may be used. These resins may be in the form of a paint to which a solvent or the like has been added.

[0021] The thickness of the undercoat layer is not particularly limited, but from the viewpoint of ensuring a smooth surface, it is preferably about 5 μm to 25 μm.

[0022] In order to improve the adhesion between the undercoat layer and the substrate, a primer layer may be provided between the undercoat layer and the substrate.

[0023] - Silver Mirror Layer - The silver mirror layer contains silver particles (precipitated silver particles) precipitated by the silver mirror reaction. The silver mirror layer is capable of transmitting millimeter waves. As described below, millimeter wave transmittance can be considered in terms of the surface resistivity of the silver mirror layer. The silver mirror layer is also capable of transmitting at least a portion of wavelengths in the visible light wavelength range. Furthermore, the silver mirror layer is also capable of transmitting at least a portion of wavelengths in the infrared wavelength range. As described below, visible light transmittance may be confirmed by the spectral transmittance of wavelengths in the visible light range for the laminate excluding the colored clear coat layer. Infrared transmittance may be confirmed by the spectral transmittance of wavelengths in the infrared range for the overall physical properties of the laminate, as described below.

[0024] The formation of the silver mirror layer by the silver mirror reaction may be carried out by contacting an aqueous ammoniacal silver nitrate solution with an aqueous reducing agent solution, which causes an oxidation-reduction reaction to produce silver particles and form the silver mirror layer.

[0025] In one embodiment of the present disclosure, the ammoniacal silver nitrate aqueous solution is obtained by dissolving silver nitrate, ammonia, and at least one amine compound selected from the group consisting of amino alcohol compounds, amino acids, and amino acid salts in water. Specific examples of the amine compound include amino alcohol compounds such as monoethanolamine, diethanolamine, diisopropanolamine, triethanolamine, and triisopropanolamine, and amino acids or salts thereof such as glycine, alanine, and sodium glycinate.

[0026] The contents of silver nitrate, ammonia, and amine compound contained in the aqueous ammoniacal silver nitrate solution are not particularly limited.

[0027] The concentration of silver nitrate contained in the ammoniacal silver nitrate aqueous solution is not particularly limited, but from the viewpoint of controlling the reaction rate, it is preferably adjusted to a range of 0.1% by mass to 10% by mass. The pH of the ammoniacal silver nitrate aqueous solution is preferably adjusted to a range of 10 to 13, more preferably 11 to 12.

[0028] In one embodiment of the present disclosure, the aqueous reducing agent solution is obtained by dissolving a reducing agent containing a phenolic compound and a strong alkaline component in water. Examples of phenolic compounds contained in the reducing agent include benzenediol compounds such as hydroquinone, catechol, and resorcinol, with hydroquinone being preferred. The reducing agent may contain only phenolic compounds or a combination of phenolic compounds and compounds other than phenolic compounds. Examples of compounds other than phenolic compounds include hydrazine compounds such as hydrazine sulfate, hydrazine carbonate, and hydrazine hydrate, sulfite compounds such as sodium sulfite, and thiosulfate compounds such as sodium thiosulfate. When the reducing agent contains a phenolic compound and a compound other than phenolic compounds, the proportion of the phenolic compound in the total reducing agent is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0029] Specific examples of the strong alkaline component contained in the aqueous reducing agent solution include sodium hydroxide and potassium hydroxide.

[0030] The aqueous reducing agent solution may contain the above-mentioned amine compound as needed. The aqueous reducing agent solution may contain a compound containing a formyl group as needed. Specific examples of the compound containing a formyl group include glucose and glyoxal. The contents of the reducing agent, strong alkaline component, amine compound (if needed), and compound containing a formyl group (if needed) contained in the aqueous reducing agent solution are not particularly limited.

[0031] The concentration of the reducing agent contained in the aqueous reducing agent solution is not particularly limited, but is preferably adjusted to a range of 0.1% by mass to 10% by mass from the viewpoint of controlling the reaction rate. The pH of the aqueous reducing agent solution is preferably adjusted to a range of 10 to 13, more preferably 10.5 to 11.5.

[0032] The average primary particle size of the silver particles in the silver mirror layer is preferably 1 nm to 30 nm, more preferably 5 nm to 25 nm, and even more preferably 10 nm to 20 nm. In particular, when the average primary particle size of the silver particles in the silver mirror layer is 15 nm or more, the uniformity of the silver mirror layer is excellent, and the appearance is improved.

[0033] The silver particles in the silver mirror layer may be aggregated to form secondary particles, and the average secondary particle size is preferably 350 nm or less, more preferably 300 nm or less, and even more preferably 250 nm or less.

[0034] The average primary particle size and average secondary particle size of silver particles are determined by measuring the diameters of 50 silver particles using a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image, and calculating the arithmetic mean.

[0035] The thickness of the silver mirror layer is not particularly limited. From the viewpoint of obtaining a sufficient metallic luster, the thickness of the silver mirror layer is preferably 50 nm or more, and from the viewpoint of obtaining a sufficient millimeter wave transmittance, the thickness of the silver mirror layer is preferably 300 nm or less.

[0036] The surface resistivity of the silver mirror layer is 10 ４ It is preferably 10 Ω / □ or more, ５It is more preferable that the surface resistivity of the silver mirror layer is Ω / □ or more. When the surface resistivity of the silver mirror layer is within the above range, it can be determined that sufficient millimeter wave transmittance has been achieved. There is no particular upper limit for the surface resistivity of the silver mirror layer. The surface resistivity of the silver mirror layer refers to a value measured in accordance with JIS K6911:2006.

[0037] A protective layer may be provided on the outer surface of the silver mirror layer to protect the silver mirror layer. The material of the protective layer is not particularly limited and can be selected, for example, from the resins described above as the material for the undercoat layer of the substrate. The thickness of the protective layer is not particularly limited and is preferably, for example, about 2 μm to 20 μm.

[0038] - Colored Clear Coat Layer - The colored clear coat layer preferably has a transparency sufficient to not conceal the metallic luster of the silver mirror layer. The color of the colored clear coat layer is not particularly limited. By changing the color of the colored clear coat layer, the metallic color can be changed, and a laminate with excellent color variation can be easily obtained.

[0039] The colored clear coat layer preferably has a transparency to the extent that it does not significantly impair the metallic luster of the silver mirror layer that is the underlying metallic decorative layer.

[0040] The material for the colored clear coat layer is not particularly limited, and can be selected from the resins mentioned above as the material for the undercoat layer, for example.

[0041] The colored clear coat layer may be a commonly used top coat layer containing a colorant, such as a pigment.

[0042] The thickness of the colored clear coat layer is not particularly limited and can be appropriately designed depending on the application.

[0043] A top coat layer may be provided on the outer side of the colored clear coat layer. The top coat layer preferably has a transparency sufficient to not obscure the metallic luster of the silver mirror layer. The material for the top coat layer is not particularly limited, and can be selected from the resins described above as the material for the undercoat layer of the substrate, for example.

[0044] The thickness of the topcoat layer is not particularly limited and can be appropriately designed depending on the application.

[0045] Fig. 1 shows a cross-sectional schematic diagram illustrating an example of a laminate of the present disclosure. The laminate 100 of Fig. 1 has, in order from the design surface side, a tinted clear coat layer 10, a substrate 20, a silver mirror layer 30, and a protective layer 40. The protective layer 40 is optional. As described above, a primer layer (not shown) and an undercoat layer (not shown) may be provided between the substrate 20 and the silver mirror layer 30.

[0046] <Physical properties of laminate> The laminate preferably has a transmission attenuation of 4.0 dB or less, more preferably 3.0 dB or less, and even more preferably 2.0 dB or less at 77.0 GHz, which is the millimeter wave region. The transmission attenuation of the laminate is measured based on JIS R1679:2007 (Method for measuring radio wave absorption characteristics of radio wave absorbers in the millimeter wave band). A sample is placed between a transmitting antenna and a receiving antenna, and the transmission attenuation is calculated from the transmitted wave (transmission coefficient) obtained by the free space method in which an electromagnetic wave is irradiated perpendicularly to the sample. The transmission attenuation can be calculated using the transmission coefficient (absolute value) according to the following formula: Transmission attenuation = 20 log １０ | (Permeability coefficient) |

[0047] In the laminate excluding the colored clear coat layer, the spectral transmittance at a wavelength of 400 nm in the visible light region is preferably 1% or more, the spectral transmittance at wavelengths from 500 nm to 600 nm is preferably 0.05% or more, and the spectral transmittance at a wavelength of 700 nm is preferably 1% or more. The spectral transmittance at wavelengths from 500 nm to 600 nm is the average value of the spectral transmittance in this wavelength region. It has been confirmed that even if the spectral transmittance at a wavelength of 580 nm measured by the following method is approximately 0.1%, the color of the backlight can be sufficiently distinguished by visual observation.

[0048] The laminate preferably has a spectral transmittance of 5% or more at a wavelength of 800 nm in the infrared region, and a spectral transmittance of 10% or more at wavelengths from 900 nm to 1600 nm, where the spectral transmittance is the average value of the spectral transmittance in this wavelength region.

[0049] In the laminate excluding the colored clear coat layer, the spectral reflectance at a wavelength of 400 nm in the visible light region is preferably 40% or more, the spectral reflectance at a wavelength of 500 nm is preferably 60% or more, the spectral reflectance at a wavelength of 600 nm is preferably 50% or more, and the spectral reflectance at wavelengths from 700 nm to 800 nm is preferably 35% or more. The spectral reflectance at wavelengths from 700 nm to 800 nm is the average value of the spectral reflectance in this wavelength region.

[0050] In the present disclosure, the spectral transmittance and spectral reflectance in the wavelength region from infrared to visible light of the laminate or the laminate excluding the colored clear coat layer are measured at 25°C in the atmosphere using an ultraviolet-visible-near-infrared (UV-VIS-NIR) spectrophotometer.

[0051] If the design surface of the laminate is gold, ＊ a ＊ b ＊ L in color system ＊ The value is preferably 70.0 or more, more preferably 75.0 or more, and even more preferably 78.0 or more. ＊ a ＊ b ＊ In the color system, L ＊ is an index of lightness, ranging from 0 (black) to 100 (white). ＊ The larger the value, the higher the brightness, indicating excellent brilliance due to the silver mirror layer.

[0052] If the design surface of the laminate is red, ＊ a ＊ b ＊ L in color system ＊ The value is preferably 50.0 or more, more preferably 55.0 or more, and even more preferably 55.5 or more. ＊ a ＊ b ＊ L in color system ＊ The value is preferably 45.0 or more, more preferably 48.0 or more, and even more preferably 50.0 or more.＊ a ＊ b ＊ L in color system ＊ The value is preferably 40.0 or more, more preferably 45.0 or more, and even more preferably 47.0 or more. ＊ a ＊ b ＊ In the color system, the gold color of the design surface is, for example, a ＊ The value is -15.0 to 15.0 and b ＊ Indicates a state where the value is 40.0 or more. ＊ a ＊ b ＊ In the color system, the design surface is red, for example, ＊ The value is -40.0 to -20.0 and b ＊ Indicates a state where the value is between 5.0 and 20.0. ＊ a ＊ b ＊ In the color system, the design surface is green, for example, ＊ The value is -50.0 to -15.0 and b ＊ Indicates a state where the value is 5.0 or more. ＊ a ＊ b ＊ In the color system, the design surface is blue, for example, a ＊ The value is -10.0 to 10.0 and b ＊ Indicates a state where the value is less than or equal to -20.0.

[0053] L ＊ a ＊ b ＊ The color system was standardized by the International Commission on Illumination (CIE) in 1976 and is adopted in JIS Z 8781-4:2013. ＊ a ＊ b ＊ L in color system ＊ is a value measured using an SCI type spectrocolorimeter (for example, CM-2600d manufactured by Konica Minolta).

[0054] <Method for producing laminate> The method for producing the laminate is not particularly limited. In forming a silver mirror layer by silver mirror reaction, the method for bringing an aqueous ammoniacal silver nitrate solution and an aqueous reducing agent solution into contact with each other is not particularly limited, and examples thereof include a method in which these aqueous solutions are applied to the surface of a substrate in a mixed state or in an unmixed state.

[0055] The method for applying the ammoniacal silver nitrate aqueous solution and the reducing agent aqueous solution to the silver mirror reaction treated surface is not particularly limited. Among these, spray coating is preferred, as it can form a uniform silver mirror layer regardless of the shape of the substrate. Spray coating can be carried out using known means such as an airbrush or a spray gun.

[0056] If necessary, the surface of the substrate may be subjected to a surface activation treatment before the silver mirror layer is formed. In one embodiment of the present disclosure, the surface activation treatment involves applying a surface activation treatment liquid containing an inorganic tin compound to the surface of the substrate. This causes tin to be present on the surface of the substrate. The presence of tin between the silver mirror layer and the substrate tends to improve adhesion between the substrate and the silver particles.

[0057] Examples of inorganic tin compounds contained in the surface activation treatment liquid include tin(II) chloride, tin(II) oxide, and tin(II) sulfate. In addition to the inorganic tin compound, the surface activation treatment liquid may contain hydrogen chloride, hydrogen peroxide, polyhydric alcohol, and the like, as needed. The content of these components contained in the surface activation treatment liquid is not particularly limited.

[0058] The pH of the surface activation treatment solution is preferably adjusted to between 0.5 and 3.0, and more preferably between 0.5 and 1.5.

[0059] Methods for applying the surface activation treatment liquid to the surface of a substrate include a method of immersing the substrate in the surface activation treatment liquid, a method of coating the surface of the substrate with the surface activation treatment liquid, etc. Among these, spray coating is preferred because it can be applied uniformly to any substrate regardless of its shape.

[0060] After the surface activation treatment, it is preferable to remove excess surface activation treatment solution from the surface of the substrate, for example, by washing the surface of the substrate with deionized water or purified distilled water.

[0061] If necessary, the surface of the substrate may be pretreated before the silver mirror layer is formed. In one embodiment of the present disclosure, as the pretreatment, a pretreatment liquid such as an aqueous silver nitrate solution is applied to the surface of the substrate after the above-described surface activation treatment. This causes silver to be present on the surface of the substrate. The presence of silver between the silver mirror layer and the substrate tends to facilitate the precipitation of silver particles of uniform size.

[0062] The pH of the pretreatment liquid is preferably adjusted to a range of 4.0 to 8.0, and more preferably to a range of 6.0 to 7.0.

[0063] Methods for applying the pretreatment liquid to the surface of the substrate include a method of immersing the substrate in the pretreatment liquid, a method of coating the surface of the substrate with the pretreatment liquid, etc. Among these, spray coating is preferred because it can apply the pretreatment liquid uniformly regardless of the shape of the substrate.

[0064] If necessary, a passivation treatment may be performed after forming a silver mirror layer on the surface of the substrate. In one embodiment of the present disclosure, the passivation treatment involves contacting the silver mirror layer with a passivation treatment solution, which is an aqueous solution containing a strong alkaline component such as potassium hydroxide and a sulfite such as sodium sulfite. This reduces the reactivity of the silver in the silver mirror layer with residual ions such as chloride ions and sulfide ions. The content of the components contained in the passivation treatment solution is not particularly limited.

[0065] The pH of the inactivation treatment solution is preferably adjusted to between 4.0 and 8.0, more preferably between 7.0 and 8.0.

[0066] Methods for bringing the inactivation treatment liquid into contact with the silver mirror layer include immersing the substrate on which the silver mirror layer has been formed in the inactivation treatment liquid, applying the inactivation treatment liquid to the silver mirror layer, etc. Among these, spray application is preferred because it can apply the inactivation treatment liquid uniformly regardless of the shape of the substrate.

[0067] Before and after the passivation treatment, it is preferable to wash the silver mirror layer with deionized water or purified distilled water.

[0068] The colored clear coat layer may be formed using a clear coat material containing a colorant. The clear coat material containing a colorant may contain, in addition to the resin described above, a solvent, an ultraviolet absorber, a curing agent, etc. The solvent may be water or an organic solvent.

[0069] The clear coating material containing the coloring agent preferably exhibits functions such as scratch prevention and ultraviolet degradation prevention.

[0070] The method for applying the clear coating material containing the colorant to the substrate is not particularly limited, and any known coating method can be used, such as dipping, screen printing, inkjet printing, dispenser coating, spin coating, brush coating, spray coating, doctor blade coating, and roll coating.

[0071] <Uses of Laminate> The laminate of the present disclosure has a metallic tone and color. Furthermore, the silver mirror layer is transparent to infrared light, visible light, and millimeter waves. Therefore, as an automobile part, the laminate can be suitably used as an automobile emblem to be placed on the front of a millimeter-wave radar transceiver. Furthermore, the laminate of the present disclosure can be used as a cover for various sensors.

[0072] Examples of sensors include sensors that detect human movement and monitor health status, and can be used as covers for indoor and outdoor sensors such as vital signs sensors, security motion sensors, automatic faucet sensors, toilet seat / standby sensors, automatic toilet seat opening / closing sensors, automatic flushing sensors, automatic lighting sensors, elderly care sensors, automatic door sensors, sensor-activated escalator sensors, remote controller sensors, non-contact body temperature sensors, sensor-activated traffic lights sensors, and traffic volume measurement sensors. The detection targets may be other than people, and may include bicycles, automobiles, airplanes, and other transportation vehicles, animals, plants, and merchandise (such as precious metals). Because the exterior is reflective, it may be placed in place of an existing mirror, or it may be placed as an interior or exterior fixture.

[0073] <Decoration Device> The decoration device of the present disclosure includes the laminate of the present disclosure and a light source arranged on the silver mirror layer side (rear side). When a backlight serving as a light source is arranged on the rear side opposite the viewing side of the laminate, light emitted from the backlight passes through the laminate and reaches the viewing side, which is the design surface. Therefore, when the laminate is observed from the viewing side, it appears to glow.

[0074] The type of light source is not particularly limited, and conventionally known light sources can be appropriately selected and used. Examples of light sources include lamp light sources and light-emitting elements. Examples include lamp light sources, incandescent lamps, halogen lamps, discharge lamps, and neon lamps. Examples of light-emitting elements include light-emitting diodes (LEDs), laser diodes (LDs), and organic electroluminescence elements. Among the above, LEDs are preferred from the viewpoints of visibility, ease of dimming, power consumption, lifespan, and the like.

[0075] The wavelength of the light emitted from the light source is not particularly limited and can be selected appropriately. For example, two or more light sources emitting light of different wavelengths may be used to create an illumination device in which light of different colors is observed depending on the location.

[0076] The light source may include a point light source, a surface light source, or two or more point light sources. When the light source includes two or more point light sources, the range of designs for the lighting device can be expanded, and the design tends to be further improved.

[0077] When the light source includes two or more point light sources, the point light sources are preferably arranged in the decoration device appropriately according to the shape of the mounting location of the vehicle, etc., and may be arranged regularly or irregularly. For example, the decoration device may have a plurality of point light sources arranged in a straight line, a curved line, or a combination thereof.

[0078] 2 is a schematic cross-sectional view showing an example of a decoration device according to the present disclosure. The decoration device 200 has a light source 110 disposed on the rear surface side opposite the viewing side. The light source 110 may be housed in a housing 120. The housing 120 is preferably light-blocking. The housing 120 may also house a millimeter-wave radar transceiver, a sensor, and the like, which will be described later, together with the light source 110.

[0079] <Millimeter-wave radar device> The millimeter-wave radar device of the present disclosure includes the laminate of the present disclosure and a millimeter-wave radar transceiver disposed on the silver mirror layer side (back side). The millimeter-wave radar transceiver can be a typical one used in automatic collision avoidance systems.

[0080] <Sensor Device> The sensor device of the present disclosure includes a laminate and a sensor disposed on the silver mirror layer side (back side). Examples of the sensor include those described above.

[0081] Hereinafter, the present disclosure will be described based on examples, but the present disclosure is not limited to the following examples.

[0082] Example 1 (1) Preparation of Substrate The surface of a 2 mm thick polycarbonate substrate was wiped with a cloth soaked in isopropyl alcohol to remove oil film, dirt, and dust, and then the substrate was dried.

[0083] (2) Surface Activation Step After the substrate was spray-washed with pure water, a surface activation treatment solution (MSPS-Sa1A, manufactured by Mitsubishi Paper Mills, Ltd.) was spray-coated onto the substrate. The substrate was then spray-washed with pure water. The surface activation treatment solution used was an aqueous solution containing tin(II) chloride, hydrogen chloride, hydrogen peroxide, and a polyhydric alcohol, with a pH of 1.0.

[0084] (3) Pretreatment Step A pretreatment liquid (MSPS-Sa2A manufactured by Mitsubishi Paper Mills Co., Ltd.) was sprayed onto the surface of the substrate after the surface activation treatment. The surface was then spray-washed with pure water. The pretreatment liquid used was a silver nitrate aqueous solution with a pH of 6.8.

[0085] (4) Silver Mirror Layer Formation Step An ammoniacal silver nitrate aqueous solution and a reducing agent aqueous solution were prepared. The ammoniacal silver nitrate aqueous solution was an aqueous solution containing silver nitrate, ammonia, and triethanolamine with a pH of 11.5 (silver nitrate concentration: 0.5% by mass). The reducing agent aqueous solution was an aqueous solution containing hydroquinone, triethanolamine, sodium hydroxide, and an amino alcohol with a pH of 10.8 (hydroquinone concentration: 4.5% by mass).

[0086] The ammoniacal silver nitrate aqueous solution and the reducing agent aqueous solution were simultaneously sprayed from separate airbrushes. The discharge rates of the airbrushes were 1.0 g / 10 seconds to 1.5 g / 10 seconds, respectively. During this process, silver particles precipitated on the surface of the substrate due to the silver mirror reaction, forming a silver mirror layer (thickness: 0.2 μm) with a silver luster. The substrate was then spray-washed with pure water.

[0087] (5) Passivation Treatment Step After the silver mirror layer formation step, the surface of the substrate was sprayed with a passivation treatment solution (MSPS-R1A, manufactured by Mitsubishi Paper Mills, Ltd.). The substrate was then spray-washed with pure water. The passivation treatment solution used was an aqueous solution containing potassium hydroxide and sulfite, with a pH of 7.5.

[0088] (6) Tinted Clear Coat Layer Formation Step A composition for a tinted clear coat layer was prepared by blending ORIGIPLATE Z clear coat agent manufactured by Origin Co., Ltd. with yellow and magenta colorants manufactured by Mitsubishi Paper Mills, Ltd. in a ratio of 100:0.4:0.2 (parts by mass). This composition was spray-coated onto the substrate on the side opposite the side on which the silver mirror layer was formed, to form a tinted clear coat layer having a thickness of 18 μm.

[0089] Comparative Example 1 An ABS (acrylonitrile-butadiene-styrene copolymer) substrate was immersed in plating solutions of copper, nickel, and chromium in that order to form plating layers, and a colored clear coat layer was formed in the area that would become the design surface in the same manner as in Example 1 to produce a laminate.

[0090] Comparative Example 2 A laminate was produced in the same manner as in Example 1, except that indium was vapor-deposited on the surface of a polycarbonate substrate instead of the silver mirror layer.

[0091] <Evaluation> (1) L＊ Measurement of L on the design surface of the obtained laminate ＊ a ＊ b ＊ L in color system ＊ was measured by the method described above. ＊ The L of the laminate of Comparative Example 1 was 78.97. ＊ The L of the laminate of Comparative Example 2 was 77.00. ＊ was 63.59.

[0092] The laminate obtained in Example 1 had a gold metallic appearance when observed from the design surface side. ＊ Although the laminate obtained in Comparative Example 2 had a gold color, the L on the design surface was peeled off during the weather resistance evaluation. ＊ The metallic tone was inferior to that of Example 1.

[0093] Laminates were prepared in the same manner as in Example 1, Comparative Example 1, and Comparative Example 2, except that the color of the colored clear coat layer was changed. ＊ When measured, the following values ​​were obtained.

[0094]

[0095] (2) Measurement of Millimeter-Wave Transmission Attenuation The attenuation (transmission attenuation) when millimeter waves (77.0 GHz) were transmitted through the gold-colored laminate was measured by the following method. The transmission attenuation was calculated from the transmitted wave (transmission coefficient) obtained by the free space method specified in JIS R1679:2007 (Method for measuring radio wave absorption characteristics of radio wave absorbers in the millimeter-wave band), in which a sample is placed between a transmitting antenna and a receiving antenna and electromagnetic waves are irradiated perpendicularly to the sample. Here, the transmission attenuation can be calculated using the transmission coefficient (absolute value) from the following formula: Transmission attenuation = 20 log １０ |(Transmission Coefficient)| The results are shown in Table 2. The millimeter wave transmission attenuation for the polycarbonate substrate alone was 0.88.

[0096]

[0097] The laminate of Comparative Example 1 did not transmit millimeter waves and measurement was not possible.

[0098] (3) Measurement of spectral transmittance and spectral reflectance in the infrared to ultraviolet region For a laminate not having a colored clear coat layer formed thereon, the spectral transmittance and spectral reflectance in the infrared to ultraviolet region were measured using a UV-VIS-NIR spectrophotometer (PerkinElmer, Lambda 950). As a reference, the spectral transmittance and spectral reflectance in the infrared to ultraviolet region were also measured for the polycarbonate (PC) substrate alone used as the substrate for the laminate.

[0099] The measurement conditions were as follows: - Use of an integrating sphere with a diameter of 150 mm - Standard sample (for 100% reflection): Spectralon manufactured by Labsphere - Wavelength range: 190 nm to 2500 nm - Wavelength interval: 5 nm steps - Measurement environment: Room temperature (25°C), in the atmosphere

[0100] In Example 1, the spectral transmittance at a wavelength of 1000 nm in the infrared region was 13.7%, and the spectral transmittance at a wavelength of 600 nm in the visible light region was 0.1%. Furthermore, in Example 1, the spectral reflectance at a wavelength of 1000 nm in the infrared region was 39.3%, and the spectral reflectance at a wavelength of 600 nm in the visible light region was 52.2%. When red, blue, and green light was irradiated from the backside of Example 1, the red, blue, and green colors were clearly distinguishable visually from the front side. Because the laminate of the example had excellent metallic gloss, metallic red, blue, and green colors were exhibited when these colors were irradiated from the backside.

[0101] (4) Backlight Irradiation A laminate without a colored clear coat layer was irradiated from the back with red, blue, and green light. In Example 1, red, blue, and green light were clearly distinguishable from the design surface side. Since the laminate of Example 1 has excellent metallic tones, when these colors were irradiated from the back, metallic red, blue, and green colors were displayed. Therefore, when a colored clear coat layer was formed, the color of the colored clear coat layer and the color of the backlight light were mixed and displayed. In Comparative Example 1, red, blue, and green light could not be distinguished from the design surface side. In Comparative Example 2, red, blue, and green light could be distinguished from the design surface side, but the metallic tones were poor.

[0102] The disclosure of Japanese Patent Application No. 2024-050258 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0103] 10 Colored clear coat layer, 20 Substrate, 30 Silver mirror layer, 40 Protective layer, 100 Laminate, 110 Light source, 120 Housing, 200 Decorating device

Claims

1. A laminate comprising, in this order, a tinted clear coat layer, a substrate, and a silver mirror layer.

2. The surface resistivity of the silver mirror layer is 10 ４ The laminate according to claim 1, having a resistance of Ω / □ or more.

3. The laminate according to claim 1 or 2, wherein the laminate excluding the colored clear coat layer has a spectral transmittance of 1% or more at a wavelength of 400 nm.

4. The laminate according to claim 1 or 2, wherein the laminate excluding the colored clear coat layer has a spectral transmittance of 0.05% or more in the wavelength range of 500 nm to 600 nm.

5. The laminate according to claim 1 or 2, wherein the laminate excluding the colored clear coat layer has a spectral transmittance of 1% or more at a wavelength of 700 nm.

6. A laminate according to claim 1 or 2, which has a spectral transmittance of 5% or more at a wavelength of 800 nm.

7. Gold color, L when measured from the side on which the colored clear coat layer is provided ＊ a ＊ b ＊ L in color system ＊ The laminate according to claim 1 or claim 2, wherein the modulus of elasticity is 70.0 or more.

8. The laminate according to claim 1 or 2, which is a sensor cover or an automobile emblem.

9. A decorating device comprising the laminate according to claim 1 or 2 and a light source disposed on the silver mirror layer side.

10. A millimeter wave radar device comprising the laminate according to claim 1 or 2 and a millimeter wave radar transmitter / receiver arranged on the silver mirror layer side.

11. A sensor device comprising the laminate according to claim 1 or 2 and a sensor disposed on the silver mirror layer side.

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