COMPOSITIONS, LAYERS AND COATING SYSTEMS FOR RADAR TRANSMISSION AND METHODS OF MANUFACTURE AND USE

Abstract

A coating composition, a coating layer, and a coating system, and a method for their preparation and use are provided; the coating system comprises an iridescence index of 2 or higher and comprises a coating layer formed by a coating composition; the coating composition comprises a film-forming resin and a pigment composition; the pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition; the coating system has a radar signal transmission of 70% or higher;The coating system has a CIELAB color difference, ?E, compared to a coating system of the same color of no more than 4, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer;

Description

COMPOSITIONS, LAYERS AND COATING SYSTEMS FOR RADAR TRANSMISSION AND METHODS OF MANUFACTURE AND USE CROSS REFERENCE This application claims priority to U.S. Patent Application No. 16 / 536,655, filed on August 9, 2019. The contents are incorporated by reference in this descriptive memorandum. FIELD OF INVENTION This disclosure relates to radar transmissive (RT) coating compositions, layers and systems and methods for their manufacture and use. BACKGROUND OF THE INVENTION Autonomous vehicles use various sensor systems, such as cameras, radar, and LIDAR (light acquisition, detection, and ranging), to detect and locate obstacles in order to navigate safely through an environment. A radar system typically includes a transmitter to emit radar waves and a receiver to receive radar waves reflected by the obstacle. Radar waves are electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz. Some surfaces can present detection challenges for certain radar systems. BRIEF DESCRIPTION OF THE INVENTION This disclosure provides a coating composition. The coating composition comprises a film-forming resin and a flake pigment composition. The flake pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a thermoplastic polyolefin (TPO) substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system. The QCPAI η / 77Π7 / 3 / YILI coating has an iridescence index of 2 or higher, where the iridescence index = 2.69 (Li-b)1“ / (Lz)0·86, and where Li is a CIELAB (International Commission on Illumination specified color space) L* value measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, Lz is a CIELAB L* value measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The coating system has a CIELAB ΔE of 4 or lower compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. This disclosure also provides a coating layer formed by a coating composition. The coating composition comprises a film-forming resin and a flake pigment composition. The flake pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO polyolefin substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system. The coating system has an iridescence index of 2 or greater, where iridescence index = 2.69 (Li-L3)111 / (L2)°·86, where Li is a CIELAB L* value measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, L2 is a CIELAB L* value measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The coating system has a CIELAB ΔE of 4 or less compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. This disclosure also provides a coating system comprising a coating layer and a radar-transmitting substrate. The coating layer is formed by a coating composition. The coating composition comprises a film-forming resin and a flake pigment composition. The flake pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO polyolefin substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system.The coating system has an iridescence index of 2 or higher, where the iridescence index = 2.69 (Li-L3)111 / (L2)°·86, and where Li is a CIELAB L* value measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, 1_2 is a CIELAB L* value measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The coating system has a CIELAB ΔE of 4 or less compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. This disclosure also provides a method for preparing a coating system. The method comprises combining a film-forming resin and a flake pigment composition to form a coating composition. The method comprises applying and curing the coating composition to form a coating layer. The flake pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO polyolefin substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system.The coating system has an iridescence index of 2 or higher, where the iridescence index = 2.69 (Li-L3)1:ll / (L2)0·86, and where Li is a CIELAB L* value measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, L2 is a CIELAB L* value measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The coating system has a CIELAB ΔE of 4 or less compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. This disclosure also provides a method for preparing a coating composition. The method comprises combining a film-forming resin and a flake pigment composition to form a coating composition. The flake pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO polyolefin substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system.The coating system has an iridescence index of 2 or higher, where the iridescence index = 2.69 (Li-L3)111 / (L2)°·86, and where Li is a CIELAB L* value measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, Lz is a CIELAB L* value measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The coating system has a CIELAB ΔE of 4 or less compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. This disclosure also provides a coating system comprising a coating layer. The coating layer comprises a film-forming resin and a pigment composition. The pigment composition comprises 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition and 0.065% to 11% by weight of aluminum flakes based on the total weight of the pigment composition. When the coating composition is applied to a TPO substrate and cured to a dry film thickness of 20 µm to form a first coating system, the first coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system. When the coating composition is applied to a TPO substrate and cured to a dry film thickness of 12 µm.7 pm to form a second coating system, the second coating system has a coverage area of ​​flaked pigments in the coating layer of 30% to 99% depending on the total coverage area of ​​the coating layer. It is understood that the inventions described in this specification are not limited to the examples summarized in this Brief Description of the Invention. Several other aspects are described and exemplified herein. BRIEF DESCRIPTION OF THE DRAWING The features and advantages of the examples, and how to achieve them, will become clearer, and the examples will be better understood, with reference to the following description of examples taken together with the accompanying drawing, where: Figure 1 is a schematic representation of an article comprising an example of a coating system according to this disclosure. The corresponding reference characters indicate the corresponding parts in the different views. The examples presented herein illustrate certain instances, in one way, and such examples should not be interpreted as limiting the scope of the examples in any way. DETAILED DESCRIPTION OF THE INVENTION The following are examples of certain aspects of this disclosure to provide a general understanding of the principles of composition, function, manufacture, and use of the compositions and methods disclosed herein. One or more examples of these aspects are illustrated in the accompanying drawing. Persons of average skill will understand that the compositions, articles, and methods specifically described herein and illustrated in the accompanying drawing are non-limiting examples and that the scope of the various examples of the present invention is defined solely by the claims. The features illustrated or described in connection with one example aspect may be combined with the features of other aspects. Such modifications and variations are intended to be included within the scope of the present invention. References throughout the descriptive report to various examples, some examples, an example, or similar phrases mean that a particular characteristic, structure, or feature described in relation to the example is included within that example. Therefore, occurrences of the phrases in various examples, in some examples, in an example, or similar phrases in various places throughout the report do not all necessarily refer to the same example. Furthermore, particular characteristics, structures, or features may be combined in any appropriate manner within one or more examples. Thus, the particular characteristics, structures, or features illustrated or described in relation to one example may be combined, in whole or in part, with the characteristics, structures, or features of one or more other examples without limitation. Such modifications and variations are intended to be included within the scope of the present examples. As used in this specification, particularly in relation to coating layers or films, the terms "on," "in," and variants thereof (e.g., applied on, formed on, deposited on, provided on, placed on, and the like) mean applied, formed, deposited, provided, or otherwise placed on a substrate surface, but not necessarily in contact with the substrate surface. For example, a coating layer applied to a substrate does not preclude the presence of another coating layer or layers of the same or different composition between the applied coating layer and the substrate.Likewise, a second coating layer applied over a first coating layer does not exclude the presence of another coating layer or layers of coating of the same or different composition between the second coating layer applied and the first coating layer applied. As used in this specification, the terms polymer and polymeric mean prepolymers, oligomers, and both homopolymers and copolymers. As used in this specification, prepolymer means a polymer precursor capable of further reactions or polymerization by means of a reactive group or groups to form a higher molecular weight or crosslinked state. As used in this specification, the terms "cure" and "curing" refer to the chemical crosslinking of components in a coating composition applied as a coating layer onto a substrate. Accordingly, the terms "cure" and "curing" do not encompass solely the physical drying of coating compositions through evaporation of the solvent or carrier. In this sense, the term "curing," as used in this specification, refers to the condition of a coating layer in which a component of the coating composition forming the layer has chemically reacted to form new covalent bonds within the coating layer (e.g., new covalent bonds formed between a binder resin and a curing agent). As used herein, the term iridescence index is defined in accordance with "Observation and Measurement of the Appearance of Metallic Materials - Part 1 - Macro Appearance," C.S. McCamy, *Color Research and Application*, Volume 21, Number 4, August 1996, pages 292-304, which is incorporated herein by reference. Specifically, the iridescence index is defined in accordance with Equation 1, which is set out below. Equation 1 iridescence index = 2.69 (L1-L3)111 / (L2)0·86 where: Li is CIELAB L* measured at the 15° specular angle 1-2 is CIELAB L* measured at the 45° specular angle, and Lses CIELAB L* measured at the specular angle of 110°. As used herein, the term silver includes neutral or gray colors, as well as chromatic colors, such as slight or significant violet, blue, green, yellow, orange, QCPRI η / 77Π7 / 3 / YILI red or a color of any hue (CIE hue value between 0 and 360°) that also exhibit a metallic appearance defined by an iridescence index of 2 or higher. Typically, a radar system can be mounted behind a vehicle's coated bumper cover and can both transmit and receive radar waves through the covered bumper. The bumper cover coating can provide a desirable aesthetic appearance. However, the coating can cause a loss of radar wave transmission, which can affect the radar system's performance. Therefore, an RT coating system and a method for its manufacture and use are provided. The RT coating system may have an iridescence index of 2 or higher and a radar transmission rate of 70% or higher. The RT coating system may comprise an RT coating layer that may include a film-forming resin and a pigment composition. The RT 104 coating layer can be applied from an RT coating composition formulated with a liquid viscosity suitable for atomization and droplet formation under the high-shear conditions associated with one- or multi-component airless spray application techniques at temperatures of -10°C or higher, such as 0°C or higher, 10°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. The RT coating composition can also be formulated with a liquid viscosity suitable for atomization and droplet formation under the high-shear conditions associated with one- or multi-component airless spray application techniques at temperatures of 60°C or lower, such as 50°C or lower, 40°C or lower, 30°C or lower, 10°C or lower, or 0°C or lower.RT coating compositions can be formulated with a liquid viscosity suitable for atomization and droplet formation under the high shear conditions associated with one- or multi-component airless spray application techniques at temperatures in the range of -10°C to 60°C, such as -10°C to 50°C, -10°C to 40°C, -10°C to 30°C, or 10°C to 40°C. The RT 104 coating layer may comprise a pigment composition suitable for providing a metallic appearance, such as a silver color, to the RT 100 coating system. For example, the RT 100 coating system may comprise an iridescence index of 2 or higher, such as 5 or higher, 10 or higher, 15 or higher, or 20 or higher. The RT 100 coating system may comprise an iridescence index of 30 or lower, such as 20 or lower, 15 or lower, 10 or lower, or 5 or lower. The RT 100 coating system may comprise an iridescence index in the range of 2 to 30, such as 5 to 30, 10 to 30, 15 to 30, 5 to 20, 10 to 20, or 15 to 20. The RT coating composition may comprise 1% or more by weight of the pigment composition, depending on the total weight of the RT coating composition, such as, 5% or more by weight of the pigment composition, 8% or more by weight of the pigment composition, 9% or more by weight of the pigment composition, 10% or more by weight of the pigment composition, 12% or more by weight of the pigment composition, 15% or more by weight of the pigment composition, or 20% or more by weight of the pigment composition, all based on the total weight of the RT coating composition.The RT coating composition may comprise 25% or less by weight of the pigment composition based on the total weight of the RT coating composition, such as, 20% or less by weight of the pigment composition, 15% or less by weight of the pigment composition, 12% or less by weight of the pigment composition, 10% or less by weight of the pigment composition, 9% or less by weight of the pigment composition, 8% or less by weight of the pigment composition, or 5% or less by weight of the pigment composition, all based on the total weight of the RT coating composition.The RT coating composition can comprise a range of 1% to 25% by weight of pigment composition depending on the total weight of the RT coating composition, such as, 1% to 15% by weight of pigment composition, 5% to 15% by weight of pigment composition, 8% to 12% by weight of pigment composition, 9% to 12% by weight of pigment composition, 10% to 12% by weight of pigment composition, or 5% to 20% by weight of pigment composition, all depending on the total weight of the RT coating composition. The pigment composition may comprise a single pigment or a mixture of different pigments. The pigment composition may include a radar-transmitting pigment and, optionally, an electrically conductive pigment (e.g., electrically conductive flake pigment), such as aluminum flakes. Furthermore, the pigment may include, for example, crude pigments such as carbazole, dioxazine, azo, monoazo, disazo, naphthol AS, salt-type (lakes), benzimidazolone, condensation, metal complex, isoindolinone, isoindoline, and polycyclic phthalocyanine, quinacridone, perylene, perinone, diketopyrrolopyrrole, thioindigo, anthraquinone, indanthrone, anthrapyrimidine, flavantrone, pyrantrone, antantrone, dioxazine, triarylcarbonium, quinophthalone pigments, diketopyrrolopyrrole red, titanium dioxide, carbon black, and combinations thereof.The pigment may comprise, for example, a finely divided solid powder that is insoluble but wettable under the conditions of use. The pigment may be organic or inorganic and may be agglomerated or non-agglomerated. The pigment may be incorporated into the RT coating composition by milling or simple mixing. The pigment may be incorporated into the coating composition by milling using a milling vehicle, such as an acrylic milling vehicle. The pigment may be a flake pigment or another suitable form. The pigment composition can affect the color of the RT 100 coating system and / or the radar transmission of the RT 100 coating system. For example, the pigment composition may comprise 50% or more by weight of radar transmitting pigment based on the total weight of the pigment composition, such as 55% or more by weight of radar transmitting pigment, 58% or more by weight of radar transmitting pigment, 60% or more by weight of radar transmitting pigment, 70% or more by weight of radar transmitting pigment, 80% or more by weight of radar transmitting pigment, 90% or more by weight of radar transmitting pigment, or 99% or more by weight of radar transmitting pigment, all based on the total weight of the pigment composition.The pigment composition may comprise 100% or less by weight of radar transmitting pigment depending on the total weight of the pigment composition, such as 99% or less by weight of radar transmitting pigment, 90% or less by weight of radar transmitting pigment, 80% or less by weight of radar transmitting pigment, 70% or less by weight of radar transmitting pigment, 60% or less by weight of radar transmitting pigment, or 55% or less by weight of radar transmitting pigment, all depending on the total weight of the pigment composition.The pigment composition may comprise 50% to 100% by weight of radar transmitting pigment, depending on the total weight of the pigment composition, such as 50% to 90% by weight of radar transmitting pigment, 55% to 100% by weight of radar transmitting pigment, 55% to 90% by weight of radar transmitting pigment, 55% to 80% by weight of radar transmitting pigment, 55% to 70% by weight of radar transmitting pigment, 55% to 60% by weight of radar transmitting pigment, 60% to 100% by weight of radar transmitting pigment, 70% to 100% by weight of radar transmitting pigment, or 80% to 90% by weight of radar transmitting pigment, all depending on the total weight of the pigment composition. The pigment composition may consist essentially of radar transmitting pigment or consist of radar transmitting pigment. The radar-transmitting pigment may be, for example, mica pigment, oxide-coated mica pigment, glass flakes, oxide-coated glass flakes, visible light diffractive pigment, visible light-reflecting organic pigment, metal oxide platelets, or a combination thereof. For example, the visible light diffraction pigment may comprise ordered arrays of particles in a polymer matrix, such as the color effect pigments described in U.S. Patent No. 6,894,086 to Munro et al. and the dye described in U.S. Patent No. 8,133,938 to Munro et al. The description of the color effect pigment in U.S. Patent No. 6,894,086 to Munro et al. and the description of the dye in U.S. Patent No. 8,133,938 to Munro et al. are incorporated herein by reference.The organic pigment that reflects visible light may comprise polymeric layers, such as, for example, the pigments described in U.S. Patent No. 6,299,979 to Neubauer et al., which is incorporated herein by reference. The metal oxide platelets may be, for example, made of aluminum oxide and titanium oxide. The radar-transmitting pigment may be electrically non-conductive. The pigment composition may comprise 50% or less by weight of electrically conductive pigment depending on the total weight of the pigment composition, such as 45% or less by weight of electrically conductive pigment, 42% or less by weight of electrically conductive pigment, 40% or less by weight of electrically conductive pigment, 30% or less by weight of electrically conductive pigment, 20% or less by weight of electrically conductive pigment, 10% or less by weight of electrically conductive pigment, 5% or less by weight of electrically conductive pigment, or 2% or less by weight of electrically conductive pigment, all depending on the total weight of the pigment composition.The pigment composition may comprise 1% or more by weight of electrically conductive pigment depending on the total weight of the pigment composition, such as 2% or more by weight of electrically conductive pigment, 5% or more by weight of electrically conductive pigment, 10% or more by weight of electrically conductive pigment, 20% or more by weight of electrically conductive pigment, 30% or more by weight of electrically conductive pigment, 40% or more by weight of electrically conductive pigment, or 45% or more by weight of electrically conductive pigment, all depending on the total weight of the pigment composition.The pigment composition may comprise 1% to 50% by weight of electrically conductive pigment, depending on the total weight of the pigment composition, such as 1% to 5% by weight of electrically conductive pigment, 5% to 45% by weight of electrically conductive pigment, 5% to 30% by weight of electrically conductive pigment, 10% to 40% by weight of electrically conductive pigment, or 30% to 50% by weight of electrically conductive pigment, all depending on the total weight of the pigment composition. The pigment composition may also not comprise an electrically conductive pigment. The electrically conductive pigment may comprise electrically conductive material or a dielectric substrate and an electrically conductive layer surrounding the dielectric substrate. The electrically conductive pigment may be, for example, aluminum flakes, steel flakes, copper flakes, silver particles, conductive carbon pigments, or a combination thereof. The pigment composition may comprise 50% or less by weight of aluminum flakes, depending on the total weight of the pigment composition, such as 45% or less by weight of aluminum flakes, 42% or less by weight of aluminum flakes, 40% or less by weight of aluminum flakes, 30% or less by weight of aluminum flakes, 20% or less by weight of aluminum flakes, 11% or less by weight of aluminum flakes, 10% or less by weight of aluminum flakes, 5% or less by weight of aluminum flakes, or 1% or less by weight of aluminum flakes, all depending on the total weight of the pigment composition. The pigment composition may also comprise 0.065% or more by weight of aluminum flakes, depending on the total weight of the pigment composition, such as 1% or more by weight of aluminum flakes. QCPRI η / 77Π7 / 3 / YILI 5% or more by weight of aluminum flakes, 10% or more by weight of aluminum flakes, 20% or more by weight of aluminum flakes, 30% or more by weight of aluminum flakes, 40% or more by weight of aluminum flakes, or 45% or more by weight of aluminum flakes, all based on the total weight of the pigment composition. The pigment composition may comprise 0.065% to 50% by weight of aluminum flakes, depending on the total weight of the pigment composition, such as 0.065% to 11% by weight of aluminum flakes, 1% to 5% by weight of aluminum flakes, 5% to 45% by weight of aluminum flakes, 5% to 30% by weight of aluminum flakes, 10% to 40% by weight of aluminum flakes, or 30% to 50% by weight of aluminum flakes, all depending on the total weight of the pigment composition. The pigment composition may not comprise aluminum flakes. The aluminum flakes may comprise Toyal Aluminum KK 634A aluminum paste and / or Toyal America TSB 2044A aluminum paste.Minimizing aluminum flakes in the pigment composition can allow for greater radar transmission by the RT coating layer. As used herein, average particle size refers to the average size at z measured using dynamic light scattering, which is the intensity-weighted harmonic average particle diameter (e.g., Dso). The average particle size for pigments, except flakes, as reported herein, was measured in accordance with ISO 22412. The average particle size for a flake, such as the aluminum flake reported herein, was measured in accordance with column 10, line 35, through column 11, line 12 of U.S. Patent No. 8,999,054, which is incorporated herein by reference. As used herein, average particle size when referring to a flake is used interchangeably with mean particle size. The pigment used in the pigment composition may comprise an average particle size of 1 µm or larger, such as 10 µm or larger, 20 µm or larger, 30 µm or larger, 40 µm or larger, 50 µm or larger, 60 µm or larger, 70 µm or larger, 80 µm or larger, or 90 µm or larger. The pigment composition may comprise an average particle size of 100 µm or smaller, such as 90 µm or smaller, 80 µm or smaller, 70 µm or smaller, 60 µm or smaller, 50 µm or smaller, 40 µm or smaller, 30 µm or smaller, 20 µm or smaller, or 10 µm or smaller. The pigment used in the pigment composition may comprise an average particle size in a range of 1 pm to 100 pm, such as 1 pm to 20 pm, 1 pm to 40 pm, 10 pm to 100 pm, 20 pm to 100 pm, 30 pm to 100 pm, 10 pm to 90 pm, 10 pm to 70 pm, 10 pm to 50 pm, 10 pm to 60 pm, 30 pm to 70 pm, or 40 pm to 60 pm. As illustrated in the Figure, an RT 100 coating system is provided comprising an RT 104 coating layer. The RT 104 coating layer can be applied to a substrate 102 and the RT 104 coating layer can be suitable for the transmission of radio waves through the RT 104 coating layer. The substrate 102 can be a radar transmitting substrate (e.g., allowing the transmission of electromagnetic radiation in a wavelength range of 1 GHz to 100 GHz with minimal absorption, scattering, or reflection, if any, through the substrate) such as a non-metallic substrate.Non-metallic substrates may include polymers, such as plastics, including polyester, polyolefin, polyamide, cellulose, polystyrene, polyacrylic, poly(ethylene naphthalate), polypropylene, polyethylene, nylon, ethylene vinyl alcohol, polylactic acid, other green polymer substrates, poly(ethylene terephthalate), polycarbonate, acrylonitrile butadiene styrene, or polyamide. Substrate 102 may comprise at least a portion of a vehicle component. A vehicle component as described herein means a part of a machine capable of carrying persons and / or cargo (e.g., a car, truck, bus, motorcycle, train, boat, airplane, spacecraft). For example, a vehicle component may comprise a bumper cover, fender, hood, trunk, door, or mirror housing. Substrate 102 can be at least partially coated with coating layer RT 104. For example, coating layer RT 104 can be applied to 5% or more of the outer surface area of ​​substrate 102, such as 10% or more, 20% or more, 50% or more, 70% or more, 90% or more, or 99% or more of the outer surface area of ​​substrate 102. Coating layer RT 104 can be applied to 100% or less of the outer surface area of ​​substrate 102, such as 99% or less, 90% or less, 70% or less, 50% or less, 20% or less, or 10% or less of the outer surface area of ​​substrate 102. Coating layer RT 104 can be applied from 5% to 100% of the outer surface area of ​​substrate 102, such as from 5% to 99%, from 5% to 90%, from 5% to 70% or from 50% to 100% of an outer surface area of ​​substrate 102. For example, the RT 104 coating layer can be a decorative coating. The dry film thickness of the RT 104 coating layer can be 0.2 µm or greater, such as 0.25 µm or greater, 2 µm or greater, 10 µm or greater, 20 µm or greater, 25 µm or greater, 50 µm or greater, or 130 µm or greater. The dry film thickness of the RT 104 coating layer can be 500 µm or less, such as 130 µm or less, 50 µm or less, 25 µm or less, 20 µm or less, 10 µm or less, 2 µm or less, or 0.25 µm or less. The dry film thickness of the RT 104 coating layer can range from 0.2 µm to 500 µm, such as 5 µm to 100 µm, 0.25 µm to 130 µm, 2 µm to 50 µm, or 10 µm to 25 µm. The RT 104 coating layer can be formed from a single layer or from a multi-layer coating stack, such as a multi-layer coating stack that includes at least two RT coating layers, a first RT coating layer and a second RT coating layer beneath at least a portion of the first RT coating layer. The system QCPRI 0 / 7707 / 3 / YILI of RT 100 coating may comprise additional layers, such as a topcoat (e.g., clearcoat) 108, a primer coat 106, and combinations thereof. The RT 104 coating layer may be applied, for example, directly onto the substrate 102, over the primer coat 106, or over another underlying layer. The topcoat 108 may be applied directly over the RT 104 coating layer or over another underlying layer (not shown). The RT 104 coating layer composition can be applied from an RT coating composition that can be formulated as a solvent-based composition, a water-based composition, or a 100% solid composition that does not comprise a volatile solvent or an aqueous carrier. The RT coating composition can be liquid at a temperature of 10°C or higher, such as 0°C or higher, 10°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. The RT coating composition can also be liquid at a temperature of 60°C or lower, such as 50°C or lower, 40°C or lower, 30°C or lower, 10°C or lower, or 0°C or lower. The RT coating composition can be liquid at a temperature in a range of -10°C to 60°C, such as 10°C to 50°C, -10°C to 40°C, -10°C to 30°C or 0°C to 40°C.The RT coating composition can be liquid at room temperature. With reference to the Figure, a radar system 110 can be placed near and / or adjacent to the coating system RT 100. The radar system 110 can transmit radio waves 112a that can pass through the coating layer RT 104 and, if present, the substrate 102, the primer layer 106, and / or the topcoat 108. However, the coating system RT 100 can reduce a portion of the transmission of the radio waves 112a, and the remaining radio waves 112b can exit the coating system RT 100. For example, the transmission of radio waves 112a through the coating system RT 100 can be reduced by reflection (e.g., as reflected radio waves 112c), absorption, and / or scattering. The remaining radio waves 112b can be used for the detection of an object (not shown).For example, the remaining 112b radio waves can be reflected off the object and return through the RT 100 coating system and be detected by the 110 radar system. Furthermore, the thickness of the RT 104 coating layer can affect the reduction in the transmission of 112a radio waves. For example, the thicker the RT 104 coating layer, the more reflection, absorption, and / or scattering can occur as the 112a radio waves pass through the thickness of the RT 104 coating layer. Similarly, the thinner the RT 103 coating layer, the less reflection, absorption, and / or scattering can occur as the 112a radio waves pass through the thickness of the RT 104 coating layer. The radar signal transmission of the RT 100 coating system can be defined QCPRI η / 77P7 / 3 / YILI as the percentage of radio waves 112a that are transmitted through the RT 100 coating system and exit the RT 100 coating system as remaining radio waves 112b. As used herein, radar signal transmission is measured by measuring the insertion loss in accordance with standard test method CTG-TM-0100-2018, available at: https: / / compasstech.com / wp-content / uploads / 2018 / 06 / CTG-Focused-Beam-Mesurement-SystemStandard.pdf, and by converting the insertion loss to radar signal transmission using Equation 2. The insertion loss can be measured by passing radio waves through a thermoplastic polyolefin (TPO) panel coated with the coating layer and, optionally, an adhesion promoter and a clear layer. Radar signal transmission can be measured in a frequency range of 1 GHz to 100 GHz.Radar signal transmission can be measured at a frequency of 24 GHz and / or 77 GHz. Equation 2 % Transmission = 100 x The RT 104 coating layer and / or the RT 100 coating system can be configured to transmit an amount of electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the RT 104 coating layer and / or the RT 100 coating system of 70% or greater, such as 75% or greater, 80% or greater, 85% or greater, 90% or greater, 95% or greater, or 99% or greater, all measured according to standard test method CTG-TM-0100-2018. The RT 104 coating layer and / or the RT 100 coating system can be configured to transmit an amount of electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the RT 104 coating layer and / or the RT 100 coating system of 100% or less, such as, 99% or less, 95% or less, 90% or less, 85% or less, 80% or less, or 75% or less, all measured according to standard test method CTG-TM-0100-2018.The RT 104 coating layer and / or the RT 100 coating system can be configured to transmit an amount of electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the RT 104 coating layer and / or the RT 100 coating system in a range of 70% to 100%, such as 80% to 100%, 70% to 90%, 80% to 90%, or 90% to 100%, all measured according to standard test method CTG-TM-0100-2018. For example, configuring the RT 104 coating layer and / or the RT 100 coating system to transmit a desired amount of electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz may comprise reducing the amount of pigments in the RT 104 coating layer and / or RT 100 coating system that reflect, absorb and / or scatter electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz. The coverage area of ​​the flake pigments in the RT 104 coating layer can affect the color and radar transmission of the RT 100 coating system. Optimizing the coverage area of ​​the flake pigments in the RT 104 coating layer may be desirable. As used herein, the phrase coverage area is a two-dimensional measure of an area occupied by a component in a coating layer where the coating layer is observed / measured from a position above and perpendicular to the plane of the surface of the coating layer, which projects the three-dimensional view of the coating layer into two dimensions (X, Y) and the area occupied by the component is compared to the total two-dimensional area occupied by the coating layer. As used herein, the term flake pigment means pigment that is in the form of flakes, wherein the ratio of the width of the pigment to the thickness of the pigment (referred to as the aspect ratio) is at least 5, such as, for example, at least 6, at least 10, at least 100, at least 200, at least 500, or at least 1,000. The aspect ratio of the pigment flakes may be less than 2,000, such as, for example, less than 1,000, less than 500, less than 200, less than 100, less than 10, or less than 6. The aspect ratio of the pigment flakes may be in the range of 5 to 2,000, such as, for example, 5 to 1,000, 10 to 2,000, 10 to 200, or 20 to 500. The pigment flakes may comprise a thickness of less than 10 micrometers as measured by scanning electron microscopy (SEM) or transmission electron microscopy (TEM), such as, for example, less than 5 micrometers, less than 0.5 micrometers, or less than 0.05 micrometers, all measured by SEM or TEM.The pigment flakes may have a thickness greater than 0.05 micrometers as measured by SEM or TEM, such as, for example, greater than 0.5 micrometers, greater than 5 micrometers, or greater than 10 micrometers, all measured by SEM or TEM. The pigment flakes may have a thickness ranging from 0.05 micrometers to 10 micrometers as measured by SEM or TEM, such as, for example, 0.5 to 5 micrometers as measured by SEM or TEM. The flaky pigment may comprise a width of less than 150 micrometers as measured by optical microscopy, SEM or TEM, such as, for example, less than 30 micrometers, less than 20 micrometers, less than 10 micrometers, less than 5 micrometers, or less than 2 micrometers, all as measured by optical microscopy, SEM or TEM.The flaky pigment may have a width greater than 1 micrometer as measured by optical microscopy, SEM, or TEM, such as, for example, greater than 2 micrometers, greater than 5 micrometers, greater than 10 micrometers, greater than 20 micrometers, greater than 30 micrometers, or greater than 150 micrometers, all measured by optical microscopy, SEM, or TEM. The flaky pigment may have a width in the range of 1 to 150 micrometers as measured by optical microscopy, SEM, or TEM, such as, for example, 5 to 30 micrometers or 10 to 15 micrometers, all measured by optical microscopy, SEM, or TEM. Flake pigments may have rounded edges, a smooth, flat surface, angular edges, and / or irregular surfaces. Flake pigments comprising flake-like particles with angular edges and / or irregular surfaces are known in the art as cornflakes. Flake pigments comprising flake-like particles distinguished by having more rounded edges and smoother, flatter surfaces are called silver dollar flakes. Flake pigments may have a coating applied to them, such as, for example, silica-coated copper flakes. Electrically conductive pigments may be flake pigments. Radar-transmitting pigments may be flake pigments. Flake pigments may be a mixture of electrically conductive pigments and radar-transmitting pigments. The RT 100 coating system may comprise a flake pigment coverage area in the RT 104 coating layer of 30% or more, depending on the total coverage area of ​​the RT 104 coating layer, such as 35% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more, all depending on the total coverage area of ​​the RT 104 coating layer. The RT 100 coating system may also comprise a flake pigment coverage area in the RT 104 coating layer of 99% or less, depending on the total coverage area of ​​the RT 104 coating layer, such as 95% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, or 40%. or less, or 35% or less, all depending on the total coverage area of ​​the RT 104 coating layer.The RT 100 coating system can comprise a coverage area of ​​flake pigments in the RT 104 coating layer in a range of 30% to 99% depending on the total coverage area of ​​the RT 104 coating layer, such as, for example, 50% to 99%, 50% to 70%, or 70% to 99%, all depending on the total coverage area of ​​the RT 104 coating layer. The coverage area of ​​the flaked pigments in the RT 104 coating layer was determined using a Keyence VK-X260K / X250K confocal laser scanning microscope in transparent film mode with a 50x objective and an RT 104 coating layer thickness ranging from 5 µm to 20 µm. The RT 104 coating layer was 12.7 µm thick when the flaked pigment coverage area was measured, as reported herein. A height map was generated from the confocal laser scanning microscope measurement, and the height range threshold for the height map was adjusted until the flaked pigments were isolated (e.g., areas with flaked pigment were blue, and all other areas without flaked pigment were black). The adjusted height map was then loaded into the software. Image analysis] {image analysis software available at https: / / imagej.nih.The image was obtained from the National Institutes of Health (Bethesda, Maryland) and binarized to create a black-and-white image where areas where the flaky pigment is present are one color (e.g., black or white) and all other areas where the flaky pigment is absent are the opposite color. The coverage area of ​​the flaky pigments in the RT104 coating layer, as reported herein, was calculated based on the area covered by the color representing the flaky pigments in the binarized image using ImageJ analysis software, relative to the total coverage area of ​​both colors. Typical coating systems with a coating layer comprising a pigment composition consisting of aluminum flakes may have a desirable aesthetic appearance, but they can undesirably reduce radio wave transmission. The pigment composition in the RT 104 coating layer may affect the aesthetic appearance of the RT 100 coating system and / or the radio wave transmission through the RT 100 coating system. Therefore, it may be desirable to minimize the CIELAB color difference (ΔE) of the RT 100 coating system compared to a coating system of the same color while maintaining the desired radio wave transmission through the RT 100 coating system.As used herein, the phrase "a color-same coating system" refers to a reference coating system that includes a coating composition used for the topcoat layer comprising a flake pigment composition consisting of aluminum flakes. For example, the difference between the RT 100 coating system and the reference color-same coating system might be the amount of aluminum flakes present in the flake pigment composition of each respective system, if any. The ΔE values ​​reported herein were determined using a multi-angle spectrophotometer, such as a BYKmac i, with D65 illumination and a 10° observer. ΔE is the difference between two colors in the CIELAB color space as a function of the difference between the collected values ​​of L*, a* and b* according to Equation 3. Equation 3 JE = + (Ja“)2+ (Jh*)2 The ΔE measurements stated herein were determined from a coating system comprising a substrate, a primer, a topcoat, and a clearcoat. When compared to the coating system of the same color, the RT 100 coating system may comprise a ΔE of 15 or less, measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 12 or less, 10 or less, 8 or less, or 5 or less, all measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.When compared to a coating system of the same color, the RT 100 coating system may comprise a ΔE of 3 or greater, measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 5 or greater, 8 or greater, 10 or greater, or 12 or greater, all measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system can comprise a ΔE in a range of 3 to 15 measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 3 to 5, 3 to 8, 3 to 10, 3 to 12, 5 to 15, 8 to 15, 10 to 15, 12 to 15, 5 to 8, or 8 to 12 measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system may comprise a ΔE of 6 or less, measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 5 or less, 4 or less, 3 or less, or 2 or less, all measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system may comprise a ΔE of 1 or greater, measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2 or greater, 3 or greater, 4 or greater, or 5 or greater, all measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.When compared to a coating system of the same color, the RT 100 coating system can comprise a ΔE in a range of 1 to 6 compared to a coating system of the same color measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as, 1 to 2, 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, 2 to 5, 2 to 6, 3 to 4, 3 to 5, 3 to 6, 4 to 5, 4 to 6, or 5 to 6 measured at 25°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system of this disclosure may comprise a ΔE of 5 or less measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 4 or less, 3 or less, or 2 or less, all measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system of this disclosure may comprise a ΔE of 1 or greater measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2 or greater, 3 or greater, or 4 or greater, all measured at 45°. QCPRI η / 77P7 / 3 / YILI measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. In comparison with a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE in a range of 1 to 5 measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2, 3, 4, 2a 3, 2a 4, 2a 5, 3a 4, 3a 5 or 4a 5, all measured at 45°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating layer of this disclosure may comprise a ΔE of 5 or less measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 4 or less, 3 or less, or 2 or less, all measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system of this disclosure may comprise a ΔE of 1 or greater measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2 or greater, 3 or greater, or 4 or greater, all measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.In comparison to a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE in a range of 1 to 5 measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2, 3, 4, 2a 3, 2a 4, 2a 5, 3a 4, 3a 5 or 4a 5, all measured at 75°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE of 4 or less measured at 110°, by use of a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 3 or less, 2 or less, or 1 or less, all measured at 110°, by use of a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a coating system of the same color, the RT 100 coating system of this disclosure may comprise a ΔE of 0.5 or greater as measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 1 or greater, 2 or greater, or 3 or greater, all as measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.In comparison to a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE in a range of 0.5 to 4 measured at 110°, by the use of a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as, 0.5 to 1, 0.5 to 2, 0.5 to 3, 1 to 2, 1 to 3, 1 to 4, 2 to 3, 2 to 4, or 3 to 4, all measured at 110°, by the use of a multi-angle spectrophotometer with D65 illumination and a 10° observer. In comparison to a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE of 7 or less based on an average of measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 6 or less, 5 or less, 4 or less, 3 or less, 2 or less, all based on an average of measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.In comparison to a color coating system, the RT 100 coating system of the present disclosure may comprise a ΔE of 1 or greater based on an average of measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 2 or greater, 3 or greater, 4 or greater, 5 or greater, 6 or greater, all based on an average of measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.In comparison to a coating system of the same color, the RT 100 coating system of the present disclosure may comprise a ΔE in a range of 1 to 7 as a function of averaging measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 1 to 3, 1 to 5, 2 to 3, 2 to 4, 2 to 7, 3 to 4, 3 to 7, 4 to 5, 4 to 7 or 6 to 7, all as a function of averaging measurements at 15°, 25°, 45°, 75° and 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. Primer layer 106 may be applied adjacent to topcoat layer RT 104. Primer layer 106 may decrease the ΔE of the RT 100 coating system compared to a system of the same color. For example, primer layer 106 may be opaque and may darken the color of substrate 102 (e.g., primer layer 106 may be hidden). Primer layer 106 may not contain an effect pigment, such as a reflective pigment, a refractive pigment, a specular pigment, or an iridescent pigment. The 106 primer layer may comprise a CIELAB L* value of 40 or less, as measured by an integrating sphere spectrometer, with D65 illumination, 10° observer, and specular component included, such as 38 or less, 36 or less, 34 or less, or 32 or less, all as measured by the use of an integrating sphere spectrometer, with D65 illumination, 10° observer, and specular component included.Primer layer 106 may comprise a CIELAB L* value of 30 or greater, measured by an integrating sphere spectrometer, with D65 illumination, 10° observer, and specular component included, such as 32 or greater, 34 or greater, 36 or greater, or 38 or greater, all measured by an integrating sphere spectrometer, with D65 illumination, 10° observer, and specular component included. Primer layer 106 may have a CIELAB L* value of 30 to 40, measured by an integrating sphere spectrometer, with D65 illumination, 10° observer, and specular component included, such as 30 to 40. QCPRI η / 77Π7 / 3 / YILI 38, 30 to 36, 30 to 34, 30 to 32, 32 to 40, 34 to 40, 36 to 40, 38 to 40, 32 to 38, 34 to 36, all measured using an integrating sphere spectrometer, with D65 illumination, 10° observer and specular component included. The measurements of primer layer 106 as reported herein were determined with the primer layer applied over substrate 102. The RT 104 coating layer can be applied from an RT coating composition comprising a film-forming resin. The film-forming resin may include a resin capable of forming a continuous, self-supporting film on substrate 102 or another underlying layer after the removal of any thinner or carrier present with the film-forming resin or after curing at room temperature or elevated temperature. A film-forming resin may comprise any resin used in an original equipment manufacturer (OEM) automotive coating composition, an automotive refinishing coating composition, an industrial coating composition, an architectural coating composition, a coil coating composition, a packaging coating composition, a marine coating composition, and an aerospace coating composition, and the like.Film-forming resin refers to resins that are self-crosslinking, resins that crosslink by reaction with a crosslinking agent, mixtures of these, and similar products. In other words, film-forming resin can include both a resin and a crosslinking agent. Film-forming resin may comprise a thermoset film-forming resin, a thermoplastic film-forming resin, or a combination thereof. As used herein, the term thermoset refers to resins that settle irreversibly upon curing or crosslinking, where the polymer chains of the polymeric components are joined by covalent bonds, often induced, for example, by heat or radiation. The curing or crosslinking reaction may also be carried out under ambient conditions or at elevated temperatures. Once cured or crosslinked, a thermoset film-forming resin may not melt upon the application of heat and may be insoluble in conventional solvents.As used herein, the term thermoplastic refers to resins that include polymeric components that are not bonded by covalent bonds and can therefore be subjected to liquid flow after heating and are soluble in conventional solvents. Thermoset coating compositions may include a crosslinking agent that can be selected from, for example, aminoplasts, polyisocyanates (including blocked isocyanates), polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, materials with organometallic acid functionality, polyamines, polyamides, and mixtures of any of the above. A film-forming resin may have functional groups that are reactive with the crosslinking agent. The film-forming resin in the coating layers described herein may be selected from any of a variety of polymers known in the art. The film-forming resin may be selected from, for example, acrylic polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, polysiloxane polymers, copolymers of these, and mixtures thereof. In general, these polymers may be any polymer of these types manufactured by any method known to persons of a mid-level skill.The functional groups in the film-forming resin can be selected from any of a variety of reactive functional groups including, for example, carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups, thiol groups, carbamate groups, amide groups, urea groups, isocyanate groups (including blocked isocyanate groups), mercaptan groups, and combinations thereof. A method for preparing an RT coating comprises combining a film-forming resin and a pigment composition to form an RT 104 coating layer comprising an iridescence index of 2 or greater. The iridescence index of 2 or greater can be achieved by formulating a pigment composition in accordance with this disclosure. The RT coating layer can comprise a radar transmission greater than 70%, such as greater than 80%. A method for applying a coating system to a substrate comprises applying an RT coating composition to at least a portion of a substrate 102 to form the RT coating layer 104. The RT coating composition can be applied by spray coating, rotary coating, dip coating, roller coating, flow coating, film coating, or a combination thereof. After applying the RT coating composition to the substrate 102, the RT coating composition can be allowed to fuse to form a substantially continuous film on the substrate 102, and the RT coating composition can be cured from the RT coating layer 104. The RT coating composition can be cured at a temperature of 10°C or higher, such as 100°C or higher.The RT coating composition can be cured at temperatures ranging from -10°C to 175°C. Curing may involve oven baking. Additional layers, such as topcoat 108, primer 106, and combinations thereof, can be applied before or after the RT coating layer 104. In some instances, the RT coating layer 104 can be manufactured as a preformed film and then applied to the substrate. For example, the coating composition can be applied to a substrate, cured, and then removed from the substrate as a preformed film. A release agent may or may not be used to facilitate the removal of the preformed film from the substrate. EXAMPLES This disclosure will be better understood by reference to the following examples, which provide non-limiting and illustrative aspects of the invention. It is understood that the invention described herein is not necessarily limited to the examples described in this section. As used herein, the term parts means parts by weight unless otherwise stated. Example 1 - Polyethylene dispersion AC® 629 oxidized polyethylene was purchased through Honeywell. To prepare the polyethylene dispersion, a tank was charged with 219.59 pounds (lbs) of xylene. With the mixture ignited, 146.25 lbs of AC® 629 oxidized polyethylene was added to the tank, and a nitrogen spray was applied. The material in the tank was heated to 170 degrees Fahrenheit (°F) and held until dissolved. The material in the tank was then cooled to 160°F and held for 30 minutes, after which 365.98 lbs of xylene were added. The material in the tank was then cooled to 120°F for 30 minutes, and the polyethylene dispersion was formed. Example 2 - antisedimentation intermediary Claytone 546 was purchased through BYK Additives and Instruments. 49.54 lbs. of polyethylene dispersion from Example 1 was premixed for 45 minutes under Cowles stirring with 362.07 lbs. of n-butyl acetate and 300.68 lbs. of acrylic milling vehicle in a container. The acrylic milling vehicle consisted of 1% tertiary dodecyl mercaptan, 1% inhibited glacial acrylic acid, 10% 2-hydroxyethyl acrylate, 19% n-butyl methacrylate, 2% methacrylic acid, 20% 2-ethylhexyl acrylate, 18% methyl methacrylate, and 29% styrene produced in 53% solids by weight in 22% isobutyl alcohol / 67% VM&P exempt naphtha / 11% n-butyl acetate solvent mixture. 61.93 lbs. of Claytone 546 was added to the vessel and mixed at high speed for 60 minutes using a Cowles blade. The material was then milled in a horizontal mill with 1 mm media for two hours to create an anti-sedimentation intermediate. Example 3 - Paint Base Preparation The components listed in Table 1 were added in the order they appear in Table 1 while mixing at low speed to create a paint base. Conventional solvent-based dyes (e.g., carbon black, pigment blue 60, T1O2 white, pigment blue 15:2, pigment violet 29) were used in the preparation of the paint base. QCPRI 0 / 7707 / 3 / YILI Table 1 - Paint base components Order of Addition Component Description Manufacturer Weight (g) 1. Diylisobutyl ketone Solvent Dow Chemical Co. 106.80 2. n-Butyl propionate Solvent Dow Chemical Co. 26.66 3. Automotive topcoat microgel Acrylic resin1 PPG 72.76 4. Resimene CD-6528 Melamine resin INEOS 48.53 5. Resimene 758 Melamine resin INEOS 79.89 6. Resimene MR-225 Melamine resin INEOS 20.81 7. Anti-sedimentation intermediate of Example 2 Additive PPG 48.38 8. Acrylic polyol A Acrylic resin2 PPG 23.73 9. Acrylic polyol B Acrylic resin3 PPG 77.34 10. Polyester A Polyester Resin4 PPG 46.54 11th Phosphated Epoxy Polymer Epoxy Resin5 PPG 1.36 12th Primary Amyl Alcohol BASF Solvent 15.94 13th PolyTHF 1000 BASF Polyol Resin 5.41 14th Carbon Black Dye PPG Dye 1.55 15th Carbon Black Dye blue pigment 60 PPG Dye 0.56 16th White T1O2 Dye PPG Dye 0.25 17th Blue Pigment Dye 15:2 PPG Dye 0.17 18th Violet Pigment Dye 29 PPG Dye 0.39 19.° Polyester B Polyester resin6 PPG 10.72 20.° n-Butyl acetate grade u reta no Solvent BASF 44.98. 1Prepared as described in Example 1 in U.S. Patent No. 5,212,273. 2Acrylic Polyol A consists of 18% n-butyl methacrylate, 40% hydroxypropyl acrylate, 1% methyl methacrylate, 20% styrene, 19% n-butyl acrylate and 2% glacial acrylic acid produced in 67% solids by weight in 58% propylene glycol methyl ether acetate / 39% aromatic 10 100 / 3% acetone solvent mixture with a weight average molecular weight GPC of 8600 and an acid value of 10.6. 3Acrylic Polyol B consists of 1% tertiary dodecane thiol, 10% 2-hydroxyethyl acrylate, 19% n-butyl methacrylate, 2% methacrylic acid, 20% 2-ethylhexyl acrylate, 18% methyl methacrylate and 30% styrene produced in 51% solids by weight in 22% isobutyl alcohol / 68% VM8rP exempt naphtha / 10% toluene solvent mixture. 4Polyester A consists of 8% adipic acid, 34% isophthalic acid, 16% E-caprolactone, 18% dimethyl-2,2-propanediol-1,3, 16% neopentyl glycol hydroxypivalate and 8% trimethylolpropane produced in 71% solids by weight in an n-butyl acetate solvent. 5The phosphated epoxy polymer consists of 67% Eponex 1511 (Hexion Specialty Chemicals) and 85% phosphoric acid produced in 60% solids by weight in a 91% exilo cellosolve / 9% deionized water solvent mixture. 6Polyester B consists of 59% Empol 1008 dimer acid (BASF), 17% neopentyl glycol, 18% cyclohexanedimethanol-1,4 and 6% trimethylolpropane produced pure in 100% solids by weight. Example 4 - Silver Coating Formulations The paint base prepared in Example 3 was used to prepare silver color coatings (SCCs), specifically SCC 1, SCC 2, and SCC 3, as shown in Table 2, with varying levels of aluminum and mica flakes. The components of SCCs 1–3 listed in Table 2 were combined and thoroughly mixed to create SCCs 1–3. The compositions of SCCs 1–3 are listed in Table 3 as a percentage by weight. Table 2 - Compositions of silver CCs Component Silver Coating 1 Silver Coating 2 Silver Coating 3 Paint Base (g) 635.18 587.79 668.56 Aluminum Paste 634A7 (g) 32.41 30.00 — Aluminum Paste TSB 2044A8 (g) 32.41 — — KT-7104 (g)9 — 30.00 33.01 Iriodin 9602 Silver-Gray 10 (g) — 33.01 Total (g) 700.00 647.79 734.58 7. Aluminum Paste 634A was acquired through Toyal Aluminum KK 8TSB 2044A Aluminum Paste was acquired through Toyal America. 9. Bright white mica KT-7104 was acquired through Kolortek Co., Ltd. 10Iriodin 9602 Gray-Silver mica was acquired through EMD Performance Materials. Table 3 - Compositions of silver CCs as a function of percentage by weight Panel Pigment Composition (% by weight based on total weight of color coating) Aluminum Flakes (% by weight based on weight of pigment composition) Mica (% by weight based on weight of pigment composition) Silver CC 1 9.26 100 0 Silver CC 2 9.26 41.5 58.5 Silver CC 3 8.98 0 100 Example 5 - Application of the coating system to the panels Automotive TPO panels (Lyondell Hasell Hifax TPO, Standard Plaque Inc.) measuring 4 inches wide, 12 inches long, and 0.118 inches thick were sprayed with the commercial adhesion promoter CMPP3700, available from PPG Industries Inc., Pittsburgh, PA, to a dry film thickness of 7 µm. The TPO panels coated with the adhesion promoter were dried under ambient conditions. The CIELAB color of the TPO panels was measured before and after the application of the adhesion promoter using specular-excluded data from an X-rite Color i7800 integrating sphere spectrometer with D65 illumination and a 10° observer. The results are listed in Table 4. Table 4: Color data of TPO panel and TPO panel coated with adhesion promoter Sample L* a* b* TPO panel only 20.87 0.13 0.30 - coated adhesion TPO panel with promoter 35.59 0.71 - 4.50 - The TPO panels coated with adhesion promoter were then coated with the silver CC 1-3 prepared in Example 4 using a spray gun mounted on a Spraymation model No. 310881. The Spraymation travel speed was set to 1,000 inches per minute, the spray gun opened in 20 pulses, and the silver CC 1-3 was applied in two coats for a total dry film thickness of 20 µm for the respective panels. The TPO panels coated with the silver CC 1-3 were evaporated under ambient conditions for two minutes followed by a five-minute bake at 80°C. The commercial clearcoat TKU2000CS is available from PPG Industries Inc.In Pittsburgh, PA, the silver CC 1-3 coated TPO panels were then applied in two coats to a total dry film thickness of 46 µm at a travel speed of 850 inches per minute with the spray gun open for 28 pulses, followed by 10 minutes of ambient evaporation and then a 30-minute bake at 141°C on each panel to create silver panels 1-3. Silver panel 1 is a TPO panel coated with an adhesion promoter, silver CC 1, and a clear coat. Silver panel 2 is a TPO panel coated with an adhesion promoter, silver CC 2, and a clear coat. Silver panel 3 is a TPO panel coated with an adhesion promoter, silver CC 3, and a clear coat. Example 6 - Measurements The silver panels 1-3 prepared in Example 5 were measured for CIELAB color from multiple angles using a BYK-mac i spectrophotometer. To determine the color difference between the control silver panel 1 and the inventive silver panels 23, the L*, a*, and b* values ​​of the silver panels 1-3 were measured using a BKY-mac i spectrophotometer with D65 illumination and a 10° observer. The color data for each silver panel 1-3 are listed in Tables 5-7. The iridescence index for the silver panels 13 was calculated using Equation 1 and is listed in Table 5. The color difference values, ΔE, for the silver panels 1-3 were calculated using Equation 3 and are listed in Table 8. Table 5 - CIELAB L* values ​​for silver panels 1-3 Panel Angle of measurement Iridescence index 15° 25° 45° 75° 110° Silver panel 1 148.81 105.14 52.56 31.26 26.04 18.6 Silver panel 2 137.40 100.78 55.93 34.97 28.42 15.4 Silver panel 3 116.30 76.56 36.93 22.48 18.53 19.5 Table 6 - CIELAB a* values ​​for silver panels 1-3 Panel Angle of measurement 15° 25° 45° 75° 110° Silver panel 1 -0.64 -0.44 -0.33 -0.33 -0.49 Silver panel 2 -0.82 -0.38 -0.34 -0.37 -0.50 Silver panel 3 -2.14 -1.46 -0.72 -0.04 0.21 Table 7 - CIELAB b* values ​​for silver panels 1-3 Panel Angle of measurement 5° 5° 5° 5° 10° 1 Silver panel 1 0.21 0.90 1.00 1.14 1.56 - Silver panel 2 0.80 0.17 0.76 1.74 2.72 Silver panel 3 4.27 3.35 3.91 5.00 5.42 - Table 8 - Color difference values, ΔE, for silver panels 1-3 Measurement Angle Panel 15° 25° 45° 75° 110° Average Measurements Silver Panel 1 0 0 0 0 0 0 Panel 11.42 4.42 3.37 3.76 2.65 5.12 Silver 2 Silver Panel 3 32.79 28.70 15.91 9.59 8.47 19.09 Insertion loss was measured using a focused beam method at Compass Technology Group (Alpharetta, Georgia) for silver panels 1-3, in accordance with standard test method CTG-TM-0100-2018, available at: https: / / compasstech.com / wpcontent / uploads / 2018 / 06 / CTG-Focused-Beam-Mesurement-System-Standard.pdf. The insertion loss measurement was performed over a radar range of 60 GHz to 90 GHz (3001 points) using an IF bandwidth of 1000 Hz, no averaging factor, and a time-domain gate of 0.5 ns. Insertion loss was measured on a Copper Mountain Technologies 4220 network analyzer driving the E-Band modules using the manufacturer's recommended power levels. Insertion loss was measured by passing radio waves with a frequency of 77 GHz through the TPO panel, the adhesion promoter, the silver coating layer, and the clear layer. The insertion loss at 77 GHz was reported in decibels (dB) and converted to a percentage of transmission using Equation 2. The insertion loss results are listed in Table 9. Table 9 - Insertion loss and transmission percentage for silver panels 1-3 Panel Insertion Loss at 77 GHz (dB) Transmission Percentage at 77 GHz Silver Panel 1 -1.97 63.5 Silver Panel 2 -1.41 72.3 Silver Panel 3 -1.11 77.4 As shown in Table 9, silver panel 2 has a 14% improvement in radar signal transmission compared to silver panel 1 measured at 77 GHz according to CTGTM-0100-2018. Silver panel 3 has a 22% improvement in radar signal transmission compared to silver panel 1 measured at 77 GHz according to CTG-TM-0100-2018. Although the examples show the use of a pigment composition comprising 41.5% by weight of aluminum flakes and 58.5% by weight of mica and a pigment composition comprising 100% mica, it shall be understood that the RT coating layer may comprise a ΔE and radar signal transmission in all ranges of aluminum flakes and mica described herein. Example 7 - Coverage Area The silver panels 1-3 prepared in Example 5 were measured to determine the coverage area of ​​the flaked pigments (e.g., aluminum and mica flakes) on the cured CC 1-3. The coverage area of ​​the flaked pigments of the cured CC 1-3 on the silver panels 1-3 was determined using a Keyence VK-X260K / X250K confocal laser scanning microscope in clear film mode with a 50x objective. The microscope height map output was adjusted to isolate the flaked pigment and binarized using ImageJ software to calculate the coverage area of ​​the flaked pigments of the cured CC 1-3 on the silver panels 1-3. The results are listed in Table 10. QCPRI η / 77Π7 / 3 / YILI Table 10 - Coverage area for silver panels 1-3 Panel Area of ​​pigment flake coverage (%) Silver panel 1 98.09 ± 0.95 Silver panel 2 98.88 ± 0.09 Silver panel 3 97.41 ± 0.13 As shown in Table 10, the coverage area of ​​the flaked pigments of the silver CC 1-3 cured on the silver panels 1-3 was sufficient to provide a desired color of the respective panel. Example 8 - additional silver-colored coatings The components listed in Table 11 were added starting at the top of Table 11 to create a silver color coating 4 (CC silver 4) similar to Chinese patent application No. 201811630188.2 by Zhong-min et al. Components 1-7 were added while mixing with a dispersion paddle (e.g., Cowles) until homogeneity was achieved, then the remaining components were added while mixing with a propeller-type mixing paddle. Additionally, a control coating (CC silver 5) was made identical to CC silver 4, except that the mica pigment was replaced with the same volume of aluminum flakes. The components listed in Table 12 were added in the order they appear in Table 12, in the same manner as those in Table 11, to create CC silver 5. Table 11 - Formulation of silver CC 4 Order of additional component Description Weight (g) 1. Ceratix 8561, BYK EVA copolymer wax 14.1 2. Maleic anhydride copolymer Acrylic resin Single-component acrylic resin with non-volatile hydroxyl group content less than 2.0 4.9 3. Setal 90173, Setalux 91715, or Setalux 91795 Modified resin Modified polyester with anti-slip agent 1.8 4. Allnex Setamin e US138 Amino rheological agent 3.1 5. CAB 5311 Cellulose acetate 15.3 6. CAB 381- 0.5 Cellulose acetate 12.2 7. BYK 300 Leveling agents 0.3 8. Merck Iriodin 9602 Mica pigment 4.3 9. Efka FA 4665 Dispersing Agents 0.2 10° Butyl Acetate Solvent 43.8 QCPRI η / 77Π7 / 3 / YILI

[0001] Table 12 - Formulation of silver CC 5 Order of addition Component Description Weight (g) 1st Ceratix 8561, BYK EVA copolymer wax 13.9 2nd Anhydride copolymer 0 Acrylic resin Single-component acrylic resin with hydroxyl group content in non-volatile less than 2.0 4.8 Maleic acrylic 3.° Setal 90173, Seta lux 91715, or Setalux 91795 Modified resin Modified polyester with anti-slip agent 1.8 4.° Allnex Setamin e US138 Amino rheological agent 3.0 5.° CAB 5311 Cellulose acetate 15.1 6.° CAB 381- 0.5 Cellulose acetate 12.1 7.° BYK 300 Leveling agents 0.3 8.° Aluminum paste, Toyal 6340NS Aluminum flake pigment 2.7 9.° Aluminum paste, Toya ITSB 2044A Aluminum flake pigment 2.6 10.° Efka FA 4665 Dispersing agents 0.2 11.° Butyl acetate Solvent 43.3 Subsequently, TPO panels (Lyondell Basell H1FaxTRC779X, 4 in x 12 in x 0.118 in, available through Standard Plaque, Inc.) were cleaned with SXA-330 and coated with PPG Industries' SU-4903 adhesion promoter. The CIELAB color of the five TPO panels after application of the adhesion promoter was measured using specular-excluded data from an X-rite Color i7800 integrating sphere spectrometer with D65 illumination and a 10° observer. The results are listed in Table 13. Table 13: Color data for TPO panels and TPO panels coated with adhesion promoter Sample L* a* b* TPO panel only 20.85 0.04 -0.85 TPO panel + adhesion promoter 21.23 0.05 -0.44 Next, some TPO panels coated with adhesion promoter were sprayed with silver CC4 from Table 11 (silver panel 4), and other TPO panels coated with adhesion promoter were sprayed with silver CC5 from Table 12 (silver panel 5). Both the silver CC4 and silver CC5 were sprayed after dilution with DT870 (available through PPG Industries) in a 2:1 volume ratio of either CC4 silver or CC5 silver to DT870. In addition, silver panels 4 and 5 were coated with a DC4000 topcoat (available through PPG Industries) using DCH3085 hardener in a 4:1 volume ratio of DC4000:DCH3085. To determine the color difference between the control, silver panel 5, and silver panel 4, the L*, a*, and b* values ​​of silver panels 4 and 5 were measured using a BKY-mac i spectrophotometer with D65 illumination and a 10° observer. The color data for each silver panel 4-5 are listed in Tables 14-16. The iridescence index for silver panels 4-5 was calculated using Equation 1 and is listed in Table 14. The color difference values, ΔE, for silver panels 4-5 were calculated using Equation 3 and are listed in Table 17. QCPRI 0 / 7707 / 3 / YILI Table 14 - CIELAB L* values ​​for silver panels 4-5 Panel Angle of measurement Iridescence index 15° 25° 45° 75° 110° Silver panel 4 109.68 77.19 38.30 20.32 14.63 18.4 Silver panel 5 135.43 102.46 58.24 37.06 30.28 14.3 Table 15 - CIELAB a* values ​​for silver panels 4-5 Panel Angle of measurement 15° 25° 45° 75° 110° Silver panel 4 -0.58 -0.33 0.07 0.49 0.74 Silver panel 5 -0.76 -0.56 -0.47 -0.54 -0.73 Table 16 - CIELAB b* values ​​for silver panels 4-5 Panel Angle of measurement 15° 25° 45° 75° 110° Silver panel 4 -2.63 -2.84 -3.45 -4.82 -5.26 Silver panel 5 0.36 -0.14 -0.41 -0.57 -0.83 Table 17 - Color difference values, ΔE, for silver panels 4-5 using silver panel 5 as a color reference. Measurement Angle Panel 15° 25° 45° 75° 110° Average Measurements Silver Panel 4 25.92 25.41 20.17 17.30 16.34 21.03 Silver Panel 5 0.00 0.00 0.00 0.00 0.00 0.00 The color difference values, ΔE, at 15° and 110° can be more difficult to match for silver-colored coatings than for other angles. As shown in Table 17 above, silver panel 4 had a color difference value, ΔE, at 15° greater than 25 and a color difference value, ΔE, at 110° greater than 16, which may be undesirable in some applications. Those with a mid-level understanding of the craft will recognize that the compositions, articles, methods described herein, and the accompanying analysis, are used as examples for the sake of conceptual clarity and that various configuration modifications are contemplated. Therefore, as used herein, the specific examples presented and their accompanying analysis are intended to be representative of their more general classes. In general, the use of any specific example is intended to be representative of its class, and the omission of specific components (e.g., operations), devices, and objects should not be considered restrictive. With regard to the attached claims, those of a mid-level trade will appreciate that the operations listed therein can generally be performed in any order. Furthermore, while the operational flows are presented in sequences, it should be understood that the various operations can be performed in orders different from those illustrated or can be performed simultaneously. Examples of such alternative arrangements may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, complementary, simultaneous, reverse, or other variant arrangements, unless the context indicates otherwise. In addition, expressions such as "responds to," "related to," or other past-tense adjectives are generally not intended to exclude such variants, unless the context indicates otherwise. While several examples have been described herein, many modifications, variations, substitutions, changes, and equivalents to these examples can be implemented and will occur to people of average skill. Furthermore, when materials are disclosed for certain components, other materials may be used. Therefore, it should be understood that the foregoing description and the accompanying claims are intended to cover all such modifications and variations that fall within the scope of the disclosed examples. The following claims are intended to cover all such modifications and variations. This specification describes various features and characteristics to provide an understanding of the composition, structure, production, function, and / or operation of the invention, including the disclosed compositions, coatings, and methods. It is understood that the various features and characteristics of the invention described herein may be combined in any suitable manner, regardless of whether such features and characteristics are expressly described in combination herein. The Inventors and the Applicant expressly intend that such combinations of features and characteristics be included within the scope of the invention described herein. As such, the claims may be amended to indicate, in any combination, any express or QCPRI η / 77Π7 / =1 / YILI inherently described in this specification, or otherwise expressly or inherently supported by it. Furthermore, the Applicant reserves the right to amend the claims to affirmatively deny features and characteristics that may be present in the prior art, even if such features and characteristics are not expressly described in this specification. Therefore, all such amendments will not add new objects to the specification or the claims and will comply with the written description, the sufficiency of the description, and the requirements of added material. Any numerical range mentioned in this specification describes all subranges of the same numerical precision (i.e., having the same number of specified digits) included within the mentioned range. For example, a mentioned range of 1.0 to 10.0 describes all subranges between (and including) the mentioned minimum value of 1.0 and the mentioned maximum value of 10.0, such as, for example, 2.4 to 7.6, even if the range of 2.4 to 7.6 is not expressly mentioned in the text of this specification. Accordingly, the Applicant reserves the right to amend this specification, including the claims, to expressly mention any subrange of the same numerical precision included within the ranges expressly mentioned herein.All these ranges are inherently described in this descriptive memorandum so that the modification to expressly mention such subranges will comply with the written description, the sufficiency of the description and the requirements of aggregated matter. Furthermore, unless expressly specified or required by the context, all numerical parameters described in this specification (such as those expressing values, ranges, quantities, percentages, and the like) may be read as if preceded by the expression "around," even if the expression "around" does not explicitly appear before a number. In addition, the numerical parameters described in this specification should be interpreted in light of the number of significant digits reported, the numerical precision, and by applying common rounding techniques. It is also understood that the numerical parameters described in this specification will necessarily possess the characteristic of inherent variability of the underlying measurement techniques used to determine the numerical value of the parameters. Although the parameters and numerical ranges that define the broad scope of the invention are approximations, the numerical values ​​stated in the specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors that necessarily result from the standard variation found in their respective test measurements. The inventions described in this specification may comprise, consist of, or consist essentially of the various features and characteristics described herein. The terms comprise (and any form of comprise, such as comprises and that comprises), have (and any form of have, such as has and that has), include (and any form of include, such as includes and that includes), and contain (and any form of contain, such as contains and that contains) are open linking verbs. Therefore, a composition, coating, or method that comprises, has, includes, or contains one or more features and / or characteristics possesses those features and / or characteristics, but is not limited to possessing only those features and / or characteristics.Similarly, a composition, coating, or method that comprises, has, includes, or contains the characteristic or characteristics and / or features possesses one or more of those characteristics and / or features, but is not limited to possessing only those one or more characteristics and / or features and may possess additional characteristics or features. The grammatical articles "a," "an," and "the," as used in this specification, including the claims, are intended to include at least one or one or more unless otherwise stated. Therefore, the articles are used in this specification to refer to one or more of one (i.e., at least one) of the grammatical objects of the article. By way of example, "a component" means one or more components and, therefore, more than one component is possibly contemplated and may be employed or used in an implementation of the compositions, coatings, and processes described. However, it is understood that the use of the expressions "at least one" or "one or more" in some cases, but not in others, will not give rise to any interpretation where the omission of the expressions limits the objects of the grammatical articles "a," "an," and "the" to only one.Furthermore, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of use requires otherwise. Any patent, publication, or other document identified in this specification is incorporated herein by reference in its entirety unless otherwise stated, but only to the extent that the incorporated material does not conflict with existing descriptions, definitions, statements, illustrations, or other disclosure material expressly set forth herein. As such, and to the extent necessary, the express disclosure as set forth herein supersedes any conflicting material incorporated by reference. Any material, or part thereof, that is incorporated by reference in this specification but conflicts with existing definitions, statements, or other disclosure material set forth herein is incorporated only to the extent that no conflict arises between that incorporated material and the existing disclosure material.The Applicant reserves the right to modify this descriptive report to expressly mention any matter, or part thereof, incorporated by reference. The modification of this descriptive report to incorporate the object shall comply with the written description, the sufficiency of the description. QCPRI η / 77Π7 / 3 / YILI and the aggregate material requirements. Although particular examples of this invention have been described above for illustrative purposes, it will be evident to persons of average skill that numerous variations of the details of the present invention can be made without departing from the invention as defined in the appended claims. While this disclosure provides descriptions of various specific aspects to illustrate different aspects of the disclosure and / or its potential applications, it is understood that persons of average skill will come up with variations and modifications. Accordingly, the invention or inventions described herein should be understood to be at least as broad as claimed and not as narrowly defined by the particular illustrative aspects provided herein.

Claims

1. A coating composition comprising: a film-forming resin; and a flake pigment composition comprising: 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition; and not more than 50% by weight of electrically conductive pigment based on the total weight of the pigment composition; wherein when the coating composition is applied onto a thermoplastic polyolefin substrate and cured to a dry film thickness of 20 µm to form a coating system, the coating system: transmits 70% or more of electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system; and has an iridescence index of 2 or greater, wherein the iridescence index = 2.69 (L1-L3)111 / (L2)0·86, and where: Li is a CIELAB L* value as measured at 15°, using a spectrophotometer with D65 illumination and a 10° observer, L2 is a CIELAB L* value as measured at 45°, using a spectrophotometer with D65 illumination and a 10° observer, and L3 is a CIELAB L* value as measured at 110°, using a spectrophotometer with D65 illumination and a 10° observer, and has a CIELAB ΔE of 4 or less compared to a coating system of the same color, measured at 110°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer. 2 - The coating composition according to claim 1, wherein the pigment composition comprises 5% to 45% by weight of aluminum flakes depending on the total weight of the pigment composition. 3 - The coating composition according to any of claims 1-2, wherein the pigment composition comprises 2% or less by weight of aluminum flakes.

4. The coating composition according to any of claims 1-3, wherein the radar transmitting pigment comprises mica pigment, oxide-coated mica pigment, glass flakes, oxide-coated glass flakes, visible light diffractive pigment, visible light-reflecting organic pigment, metal oxide platelets, or a combination thereof.

5. The coating composition according to any of claims 1-4, wherein the coating system transmits 80% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the coating system.

6. The coating composition according to any of claims 1-5, wherein the coating system comprises a CIELAB ΔE of 15 or less compared to a coating system of the same color, measured at 15°, using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

7. The coating composition according to any of claims 1-6, wherein the pigment composition comprises an average particle size of 1 pm to 100 pm. 8.- A coating layer formed by a coating composition according to any of claims 1-7.

9. The coating layer according to claim 8, wherein the coating layer comprises a dry film thickness of 5 pm to 100 pm.

10. A coating system comprising: a coating layer according to any of claims 8-9 applied onto a radar transmitting substrate.

11. The coating system according to claim 10, further comprising a primer layer applied to a substrate, wherein the CIELAB L* value of the primer layer applied to a substrate is in the range of 30 to 40 as measured with an integrating sphere spectrophotometer with D65 illumination, 10° observer and an included specular component. 12.- The coating system according to any of claims 1011, wherein the substrate comprises at least a portion of a vehicle component. 13.- The coating system according to claim 12, wherein the vehicle component comprises a radar system. 14.- The coating system in accordance with any of clauses 10-13, wherein the coating system has a coverage area of ​​flaked pigments in the coating layer of 30% to 99% depending on the total coverage area of ​​the coating layer. 15.- The coating system in accordance with any of clauses 10-13, wherein the coating system has a coverage area of ​​flaked pigments in the coating layer of 50% to 99% depending on the total coverage area of ​​the coating layer.

16. A method for preparing the coating system according to any of claims 10-15, wherein the method comprises: combining the film-forming resin and the flake pigment composition to form the coating composition; and applying and curing the coating composition to form a coating layer.

17. The method according to claim 16, further comprising applying the coating composition onto a substrate and curing the coating composition onto the substrate.

18. The method according to claim 16, further comprising applying the coating composition to a surface; curing the coating composition to form a film on the surface; removing the film from the surface to create a preformed film; and applying the preformed film onto the substrate.

19. The method according to any of claims 15-18, further comprising applying a finishing composition over the coating layer after forming the coating layer.

20. A method for preparing the coating composition according to any of claims 1-7, wherein the method comprises: combining the film-forming resin and the flake pigment composition to form the coating composition.

21. A coating composition comprising: a film-forming resin; and a flake pigment composition comprising: 50% or more by weight of radar-transmitting pigment based on the total weight of the pigment composition; and 0.065% to 11% by weight of aluminum flakes based on the total weight of the pigment composition; wherein when the coating composition is applied onto a thermoplastic polyolefin substrate and cured to a dry film thickness of 20 µm to form a first coating system, the first coating system transmits 70% or more of the electromagnetic radiation comprising a frequency of 1 GHz to 100 GHz through the first coating system, and wherein when the coating composition is applied onto a thermoplastic polyolefin substrate and cured to a dry film thickness of 12 µm.7 pm to form a coating layer, and wherein a coverage area of ​​flaked pigments in the coating layer is 30% to 99% depending on the total coverage area of ​​the coating layer. 22.- The coating composition according to claim 21, wherein the coverage area of ​​flaked pigments in the coating layer is 50% to 99% depending on the total coverage area of ​​the coating layer.