Coating compositions, coatings, and coating systems for radar transparency and methods of making and using the same

Abstract

The present invention relates to coating compositions, coatings, and coating systems for radar transparency, and methods of making and using the same. A coating composition, coating, and coating system, and methods of making and using the same are provided. The coating system has a dynamic index of 2 or greater, and the coating system includes a coating formed from a coating composition. The coating composition includes a film-forming resin and a pigment composition. The pigment composition includes: 50 wt% or more of a radar-transparent pigment, based on the total weight of the pigment composition; and no more than 50 wt% of an electrically-conductive pigment, based on the total weight of the pigment composition. The coating system has a radar signal transmission of 70% or greater. The coating system has a CIELAB color difference, i.e., delta E, of no more than 4 compared to a color-matched coating system, as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer at 110°.

Description

[0001] This application is a divisional application of Chinese patent application No. 202080057258.9, filed on August 7, 2020, entitled "Coating composition, coating and coating system for radar transmission and method of preparation and use thereof".

[0002] Cross-references

[0003] This application claims priority to U.S. Patent Application No. 16 / 536,655, filed August 9, 2019. The contents of that U.S. patent application are incorporated herein by reference. Technical Field

[0004] This disclosure relates to radar transmission (“RT”) coating compositions, coatings and coating systems, and methods for preparing and using them. Background Technology

[0005] Autonomous vehicles use various sensor systems, such as cameras, radar, and LIDAR (Light Detection and Ranging), to detect and locate obstacles in order to navigate safely in their environment. Typically, a radar system includes a transmitter to transmit radar waves and a receiver to receive radar waves reflected from obstacles. Radar waves can be electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz. Some surfaces can present detection challenges for certain radar systems. Summary of the Invention

[0006] This disclosure provides a coating composition comprising a film-forming resin and a flake-like pigment composition. The flake-like pigment composition comprises: 50% by weight or more of a radar-transmitting pigment based on the total weight of the pigment composition; and no more than 50% by weight of a 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 allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And where L1 is the CIELAB (International Commission on Illumination) color space as measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, L2, is as measured by CIELAB at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, and L3 is as measured by CIELAB at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The CIELAB ΔE of the coating system compared to a color-matched coating system is 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0007] This disclosure also provides a coating formed from a coating composition. The coating composition comprises a film-forming resin and a flake pigment composition. The flake pigment composition comprises: 50% by weight or more of a radar-transmitting pigment based on the total weight of the pigment composition; and no more than 50% by weight of a conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO substrate and cured to form a coating system with a dry film thickness of 20 µm, the coating system allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And where L1 is measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as measured by CIELAB. The value, L2, is as measured by CIELAB at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, and L3 is as measured by CIELAB at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The CIELAB ΔE of the coating system compared to a color-matched coating system is 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0008] This disclosure also provides a coating system comprising a coating and a radar-transmitting substrate. The coating is formed from a coating composition. The coating composition comprises a film-forming resin and a flake-like pigment composition. The flake-like pigment composition comprises: 50% by weight or more of a radar-transmitting pigment based on the total weight of the pigment composition; and no more than 50% by weight of a conductive pigment based on the total weight of the pigment composition. When the coating composition is applied to a TPO substrate and cured to form a coating system with a dry film thickness of 20 µm, the coating system allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And where L1 is measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as measured by CIELAB. The value, L2, is as measured by CIELAB at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, and L3 is as measured by CIELAB at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The CIELAB ΔE of the coating system compared to a color-matched coating system is 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0009] This disclosure also provides a method for preparing a coating system. The method includes combining a film-forming resin with a flake-like pigment composition to form a coating composition. The method includes applying the coating composition and curing it to form the coating. The flake-like pigment composition comprises: 50% by weight or more of a radar-transmitting pigment based on the total weight of the pigment composition; and no more than 50% by weight of a conductive pigment 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 coating system, the coating system allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And where L1 is measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as measured by CIELAB. The value, L2, is as measured by CIELAB at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, and L3 is as measured by CIELAB at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The CIELAB ΔE of the coating system compared to a color-matched coating system is 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0010] This disclosure also provides a method for preparing a coating composition. The method includes combining a film-forming resin with a flake-like pigment composition to form a coating composition. The flake-like pigment composition comprises: 50% by weight or more of a radar-transmitting pigment based on the total weight of the pigment composition; and no more than 50% by weight of a conductive pigment 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 coating system, the coating system allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And where L1 is measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as measured by CIELAB. The value, L2, is as measured by CIELAB at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The value, and L3 is as measured by CIELAB at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. The CIELAB ΔE of the coating system compared to a color-matched coating system is 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0011] 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, by weight, 50% or more of a radar-transmitting pigment; and, by weight, 0.065% to 11% of aluminum flakes. 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 allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system. When the coating composition is applied to a TPO substrate and cured to a dry film thickness of 12.7 µm to form a second coating system, the area coverage of the flake pigments in the coating of the second coating system is 30% to 99% of the total area coverage of the coating.

[0012] It should be understood that the invention described herein is not limited to the examples summarized herein. Various other aspects are described and illustrated herein. Attached Figure Description

[0013] By referring to the following description of the example in conjunction with the accompanying drawings, the features and advantages of the example, as well as how it is implemented, will become more apparent, and the example will be better understood, wherein:

[0014] Figure 1 This is a schematic diagram of an article of an example including a coating system according to the present disclosure.

[0015] Throughout the various views, corresponding reference numerals indicate the relevant parts. The examples listed herein illustrate certain instances in one form, and such examples should not be construed as limiting the scope of the instances in any way. Detailed Implementation

[0016] Certain exemplary aspects of this disclosure will now be described to provide a comprehensive understanding of the composition, function, manufacture, and use of the compositions disclosed herein, as well as the principles of the methods. One or more examples of these aspects are illustrated in the accompanying drawings. Those skilled in the art will understand that the compositions, articles, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects, and the scope of the various embodiments of the invention is uniquely defined by the claims. Features shown or described in connection with one exemplary aspect may be combined with features of other aspects. Such modifications and changes are intended to be included within the scope of the invention.

[0017] Throughout this specification, references to "various examples," "some examples," "one example," "an example," etc., indicate that a particular feature, structure, or characteristic described in connection with the example is included in that example. Therefore, phrases such as "in various examples," "in some examples," "in one example," "in an example," etc., appearing in various places throughout this specification do not necessarily refer to the same example. Furthermore, in one or more examples, a particular feature, structure, or characteristic can be combined in any suitable manner. Therefore, a particular feature, structure, or characteristic shown or described in connection with one example can be combined, in whole or in part, with the features, structures, or characteristics of another or other examples without limitation. Such modifications and changes are intended to be included within the scope of this specification.

[0018] As used herein, particularly in connection with coatings or films, the terms “on,” “to,” “above,” and variations thereof (e.g., “applied on,” “formed on,” “deposited on,” “provided on,” “located on,” etc.) mean applied, formed, applied, provided, or otherwise situated on a surface of a substrate but not necessarily in contact with said surface of the substrate. For example, a coating “applied on” a substrate does not exclude the presence of another coating or other coatings of the same or different composition located between the applied coating and the substrate. Similarly, a second coating “applied on” a first coating does not exclude the presence of another coating or other coatings of the same or different composition located between the applied second coating and the applied first coating.

[0019] As used in this specification, the term "polymer (polymer and polymeric)" means prepolymer, oligomer, homopolymer, and copolymer. As used in this specification, "prepolymer" means a polymer precursor that can be further reacted or polymerized by one or more reactive groups to form a higher molecular weight or cross-linked state.

[0020] As used herein, the terms "cure" and "curing" refer to the chemical crosslinking of components in a coating composition applied as a coating onto a substrate. Therefore, the terms "cure" and "curing" encompass more than just the physical drying of the coating composition by solvent or carrier evaporation. In this regard, the term "cured" as used herein refers to a state in which the components of the coating composition forming the layer have undergone a chemical reaction to form new covalent bonds in the coating (e.g., new covalent bonds formed between the adhesive resin and the curing agent).

[0021] As used in this article, the term "dynamic index" is based on "Observation and Measurement of the Appearance of Metallic Materials - Part 1 - Macroscopic Appearance", CS McCamy, *Color Research and Applications*. Color Research And Application) The definition is found in the reference , Vol. 21, No. 4, August 1996, pp. 292-304, which is hereby incorporated by reference. That is, the dynamic index is defined according to Equation 1 listed below.

[0022] Equation 1

[0023] Dynamic index = 2.69 (L1-L3) 1.11 / (L2) 0.86

[0024] in

[0025] L1 is measured at a 15° retroreflection angle by CIELAB. ,

[0026] L2 is measured at a 45° retroreflection angle by CIELAB. ,and

[0027] L3 is the CIELAB measurement taken at a retrograde reflection angle of l10°. .

[0028] As used herein, the term “silver” includes neutral or gray tones, as well as colors such as subtle to pronounced purple, blue, green, yellow, orange, red, or any hue (CIE hue values ​​between 0° and 360°), which also exhibit a metallic appearance as defined by a dynamic index of 2 or higher.

[0029] Typically, radar systems can be mounted behind a coated bumper cover of a vehicle and can transmit and receive radar waves through the coated bumper cover. The coating on the bumper cover provides a desired aesthetic appearance. However, the coating may cause transmission loss of radar waves, which can affect the performance of the radar system. Therefore, RT coating systems and methods for preparing and using them are provided. The dynamic index of the RT coating system can be 2 or greater and the radar transmittance is 70% or more. The RT coating system may include an RT coating, which may include a film-forming resin and pigment composition.

[0030] RT coating 104 can be applied by an RT coating composition formulated to have a specific liquid viscosity suitable for atomization and droplet formation under high shear conditions associated with single-component or multi-component airless spraying 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 to have a specific liquid viscosity suitable for atomization and droplet formation under high shear conditions associated with single-component or multi-component airless spraying 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 to have a certain liquid viscosity suitable for atomization and droplet formation under high shear conditions associated with single-component or multi-component airless spraying techniques in a temperature 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.

[0031] RT coating 104 may include a pigment composition suitable for providing a metallic appearance, such as silver, to RT coating system 100. For example, the dynamic index of RT coating system 100 may be 2 or greater, such as 5 or greater, 10 or greater, 15 or greater, or 20 or greater. The dynamic index of RT coating system 100 may be 30 or less, such as 20 or less, 15 or less, 10 or less, or 5 or less. The dynamic index of RT coating system 100 may be 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.

[0032] Based on the total weight of the RT coating composition, the RT coating composition may include 1% or more of pigment composition, such as 5% or more of pigment composition, 8% or more of pigment composition, 9% or more of pigment composition, 10% or more of pigment composition, 12% or more of pigment composition, 15% or more of pigment composition, 20% or more of pigment composition, all based on the total weight of the RT coating composition. Based on the total weight of the RT coating composition, the RT coating composition may include 25% or less of pigment composition, such as 20% or less of pigment composition, 15% or less of pigment composition, 12% or less of pigment composition, 10% or less of pigment composition, 9% or less of pigment composition, 8% or less of pigment composition, or 5% or less of pigment composition, all based on the total weight of the RT coating composition. The RT coating composition may include 1% to 25% by weight of pigment composition, such as 1% to 15% by weight, 5% to 15% by weight, 8% to 12% by weight, 9% to 12% by weight, 10% to 12% by weight, or 5% to 20% by weight, all based on the total weight of the RT coating composition.

[0033] Pigment compositions may include one pigment or a mixture of pigments. Pigment compositions may include radar-transmitting pigments and optionally conductive pigments (e.g., conductive flake pigments), such as aluminum flakes. Additionally, pigments may include, for example, carbazole dioxane crude pigments, azo, monoazo, diazo, naphthol AS, salts (lakes), benzimidazolones, condensates, metal complexes, isoindolineones, isoindoline and polycyclic phthalocyanines, quinacridones, dinaphthalene-phenylene oxide, perinone, diketopyrrolopyrrole, thioindole, anthraquinone, indoleanthraquinone, anthraquinone, flavinthrone, pinanthraquinone, anthraquinone, dioxazine, triaryl cations, quinophthalone pigments, pyrrolopyrrole dione red, titanium dioxide, carbon black, and any combination thereof. Pigments may include, for example, finely ground but wettable solid powders that are insoluble under the conditions of use. Pigments may be organic or inorganic, and may be agglomerated or non-agglomerated. Pigments may be incorporated into RT coating compositions by grinding or simple mixing. Pigments can be incorporated into the coating composition by grinding using an abrasive carrier such as an acrylic abrasive carrier. The pigments can be in flake form or other suitable shapes.

[0034] The pigment composition can affect the color and / or radar transmittance of the RT coating system 100. For example, by weight of the total pigment composition, the pigment composition may include 50% or more of radar-transmitting pigment, such as 55% or more, 58% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 99% or more, all by weight of the total pigment composition. By weight of the total pigment composition, the pigment composition may include 100% or less of radar-transmitting pigment, such as 99% or less, 90% or less, 80% or less, 70% or less, 60% or less, or 55% or less, all by weight of the total pigment composition. The pigment composition may comprise, by weight of all components, 50% to 100% radar-transmitting pigment, such as 50% to 90% radar-transmitting pigment, 55% to 100% radar-transmitting pigment, 55% to 90% radar-transmitting pigment, 55% to 80% radar-transmitting pigment, 55% to 70% radar-transmitting pigment, 55% to 60% radar-transmitting pigment, 60% to 100% radar-transmitting pigment, 70% to 100% radar-transmitting pigment, or 80% to 90% radar-transmitting pigment, all by weight of the pigment composition. The pigment composition may consist substantially of radar-transmitting pigment or be composed entirely of radar-transmitting pigment.

[0035] Radar-transmitting pigments can be, for example, mica pigments, oxide-coated mica pigments, glass sheets, oxide-coated glass sheets, visible-light diffractive pigments, visible-light reflective organic pigments, metal oxide flakes, or combinations thereof. For example, visible-light diffractive pigments can comprise ordered arrays of particles in a polymer matrix, such as the color-effect pigments described by Munro et al. in U.S. Patent No. 6,894,086 and the colorants described by Munro et al. in U.S. Patent No. 8,133,938. The descriptions of color-effect pigments by Munro et al. in U.S. Patent No. 6,894,086 and the descriptions of colorants by Munro et al. in U.S. Patent No. 8,133,938 are hereby incorporated by reference. Visible-light reflective organic pigments can comprise polymer layers, such as the pigments described by Neubauer et al. in U.S. Patent No. 6,299,979, which is hereby incorporated by reference. Metal oxide flakes can be, for example, alumina and titanium oxide. Radar-transmitting pigments can be non-conductive.

[0036] The pigment composition may include 50% or less conductive pigment by weight, such as 45% or less, 42% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% or less, all by weight of the total pigment composition. The pigment composition may also include 1% or more conductive pigment by weight, such as 2% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, or 45% or more, all by weight of the total pigment composition. The pigment composition may include 1% to 50% by weight of conductive pigment, such as 1% to 5% by weight, 5% to 45% by weight, 5% to 30% by weight, 10% to 40% by weight, or 30% to 50% by weight, all based on the total weight of the pigment composition. The pigment composition may not include conductive pigment.

[0037] Conductive pigments may include conductive materials or include a dielectric substrate and a conductive layer surrounding the dielectric substrate. Conductive pigments may be, for example, aluminum flakes, steel flakes, copper flakes, silver particles, conductive carbon pigments, or combinations thereof.

[0038] The pigment composition may include 50% by weight or less aluminum flakes, such as 45% by weight or less, 42% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 11% by weight or less, 10% by weight or less, 5% by weight or less, or 1% by weight or less, all based on the total weight of the pigment composition. The pigment composition may also include 0.065% by weight or more aluminum flakes, such as 1% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, or 45% by weight or more, all based on the total weight of the pigment composition. The pigment composition may include 0.065% to 50% aluminum flakes by weight, such as 0.065% to 11% aluminum flakes, 1% to 5% aluminum flakes, 5% to 45% aluminum flakes, 5% to 30% aluminum flakes, 10% to 40% aluminum flakes, or 30% to 50% aluminum flakes by weight, all based on the total weight of the pigment composition. The pigment composition may not include aluminum flakes. Aluminum flakes may include aluminum paste 634A from Toyal Aluminum KK and / or TSB 2044A aluminum paste from Toyal America. Minimizing aluminum flakes in the pigment composition allows for greater radar transmittance in the RT coating.

[0039] As used herein, “average particle size” refers to the z-average size measured using dynamic light scattering, which is the intensity-weighted harmonic mean particle diameter (e.g., Dij). 50 As reported herein, the average particle size of pigments other than flakes according to this disclosure is measured according to ISO-22412. The average particle size of aluminum flakes according to this disclosure, as reported herein, is measured according to column 10, line 35 through column 11, line 12 of U.S. Patent No. 8,999,054, which is hereby incorporated by reference. As used herein, “average particle size” is used interchangeably with “mean particle size” when referring to flakes.

[0040] The average particle size of the pigment used in the pigment composition can be 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 average particle size of the pigment composition can be 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 average particle size of the pigment used in the pigment composition can be in the range of 1 µm to 100 µm, such as 1 µm to 20 µm, 1 µm to 40 µm, 10 µm to 100 µm, 20 µm to 100 µm, 30 µm to 100 µm, 10 µm to 90 µm, 10 µm to 70 µm, 10 µm to 50 µm, 10 µm to 60 µm, 30 µm to 70 µm, or 40 µm to 60 µm.

[0041] As shown in the figure, an RT coating system 100 including an RT coating 104 is provided. The RT coating 104 can be applied over a substrate 102 and the RT coating 104 can be adapted to transmit radio waves across the entire RT coating 104. The substrate 102 can be a radar-transmitting substrate, such as a non-metallic substrate (e.g., allowing transmission of electromagnetic radiation in the wavelength range of 1 GHz to 100 GHz with minimal absorption, scattering, or reflection through the substrate, if any). The non-metallic substrate can comprise polymers, such as plastics, including polyesters, polyolefins, polyamides, cellulose, polystyrene, polypropylene, polyethylene naphthalate, polypropylene, polyethylene, nylon, ethylene vinyl alcohol, polylactic acid, other “green” polymer substrates, polyethylene terephthalate, polycarbonate, polycarbonate propylene butadiene styrene, or polyamide. The substrate 102 can include at least a portion of a vehicle assembly. As described herein, a vehicle assembly refers to a part of a machine (e.g., a car, truck, bus, motorcycle, train, ship, aircraft, spacecraft) capable of transporting people and / or goods. For example, vehicle components may include bumper covers, fenders, hoods, trunks, doors, or rearview mirror housings.

[0042] The substrate 102 may be at least partially coated with the RT coating 104. For example, the RT coating 104 may be applied to 5% or more of the surface area of ​​the 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 surface area of ​​the substrate 102. The RT coating 104 may also be applied to 100% or less of the surface area of ​​the 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 surface area of ​​the substrate 102. The RT coating 104 may be applied to 5% to 100% of the surface area of ​​the substrate 102, such as 5% to 99%, 5% to 90%, 5% to 70%, or 50% to 100% of the surface area of ​​the substrate 102. For example, the RT coating 104 may be a decorative coating.

[0043] The dry film thickness of the RT coating 104 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 coating 104 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 coating 104 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.

[0044] The RT coating 104 can be formed by a single layer or a multilayer coating stack, such as a multilayer coating stack containing at least two RT coatings, a first RT coating and a second RT coating located below at least a portion of the first RT coating. The RT coating system 100 may include additional layers, such as a topcoat (e.g., a varnish) 108, a primer layer 106, and combinations thereof. The RT coating 104 can be applied directly to, for example, a substrate 102, or over the primer layer 106 or other underlayers. The topcoat 108 can be applied directly to the RT coating 104 or over another underlayer (not shown).

[0045] RT coating 104 can be applied by an RT coating composition, which can be formulated as a solvent-based composition, a water-based composition, or a 100% solid composition excluding volatile solvents or aqueous carriers. The RT coating composition can be a liquid at -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 be a 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 a liquid in a temperature 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 a liquid at room temperature.

[0046] Referring to the figure, radar system 110 can be positioned near and / or adjacent to RT coating system 100. Radar system 110 can transmit radio waves 112a, which can travel through RT coating 104 and, if present, through substrate 102, primer layer 106, and / or topcoat 108. However, RT coating system 100 may reduce the transmission of a portion of radio waves 112a, and the remaining radio waves 112b may exit RT coating system 100. For example, the transmission of radio waves 112a through RT coating system 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 to detect objects (not shown). For example, the remaining radio waves 112b can be reflected from an object and return through RT coating system 100 and be detected by radar system 110. Additionally, the thickness of RT coating 104 can affect the reduction of radio wave 112a transmission. For example, the thicker the RT coating 104, the more reflection, absorption, and / or scattering may occur when radio waves 112a travel through the thickness of the RT coating 104. Similarly, the thinner the RT coating 103, the less reflection, absorption, and / or scattering may occur when radio waves 112a travel through the thickness of the RT coating 104.

[0047] The radar signal transmittance of the RT coating system 100 can be defined as the percentage of radio wave 112a that passes through and exits the RT coating system 100 as residual radio wave 112b. As used herein, “radar signal transmittance” is measured by measuring insertion loss according to the standard test method CTG-TM-0100-2018, available at: https: / / compasstech.com / wp-content / uploads / 2018 / 06 / CTG-Focused-Beam-Mesurement-System-Standard.pdf, and the insertion loss is converted to radar signal transmittance using Equation 2. Insertion loss can be measured by passing radio waves through a thermoplastic polyolefin (“TPO”) panel coated with a coating and optionally an adhesive and a clear coating. Radar signal transmittance can be measured in the frequency range of 1 GHz to 100 GHz. Radar signal transmittance can be measured at frequencies of 24 GHz and / or 77 GHz.

[0048] Equation 2

[0049]

[0050] RT coating 104 and / or RT coating system 100 may be configured such that electromagnetic radiation, including frequencies from 1 GHz to 100 GHz, is transmitted through RT coating 104 and / or RT coating system 100: 70% or more, such as 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more, all measured according to standard test method CTG-TM-0100-2018. RT coating 104 and / or RT coating system 100 may be configured such that electromagnetic radiation, including frequencies from 1 GHz to 100 GHz, is transmitted through RT coating 104 and / or RT coating system 100: 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. RT coating 104 and / or RT coating system 100 can be configured to allow electromagnetic radiation, including frequencies from 1 GHz to 100 GHz, to be transmitted through RT coating 104 and / or RT coating system 100 in the 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 RT coating 104 and / or RT coating system 100 to transmit a desired amount of electromagnetic radiation including frequencies from 1 GHz to 100 GHz may include reducing the amount of pigment in RT coating 104 and / or RT coating system 100 that reflects, absorbs, and / or scatters electromagnetic radiation including frequencies from 1 GHz to 100 GHz.

[0051] The area coverage of the flake pigments in the RT coating 104 can affect the color and radar transmittance of the RT coating system 100. Optimizing the area coverage of the flake pigments in the RT coating 104 may be desirable.

[0052] As used herein, the phrase “area coverage” is a two-dimensional measure of the area occupied by the components in a coating, where the coating is observed / measured from a position above and perpendicular to the surface of the coating, thus projecting a three-dimensional view of the coating onto two dimensions (X, Y) and comparing the area occupied by the components to the total two-dimensional area occupied by the coating.

[0053] As used herein, the term "flaky pigment" refers to a flaky pigment in which the ratio of the width to the thickness of the pigment (referred to as aspect ratio) is at least 5, such as at least 6, at least 10, at least 100, at least 200, at least 500, or at least 1,000. The aspect ratio of a flaky pigment can be less than 2,000, such as less than 1,000, less than 500, less than 200, less than 100, less than 10, or less than 6. The aspect ratio of a flaky pigment can be in the range of 5 to 2,000, such as 5 to 1,000, 10 to 2,000, 10 to 200, or 20 to 500. The thickness of the flaky pigment can be less than 10 micrometers, such as less than 5 micrometers, less than 0.5 micrometers, or less than 0.05 micrometers, all measured by SEM or TEM. The thickness of the flake-like pigment, as measured by SEM or TEM, can be greater than 0.05 micrometers, for example, greater than 0.5 micrometers, greater than 5 micrometers, or greater than 10 micrometers, all measured by SEM or TEM. The thickness of the flake-like pigment, as measured by SEM or TEM, can range from 0.05 micrometers to 10 micrometers, for example, 0.5 to 5 micrometers as measured by SEM or TEM. The width of the flake-like pigment, as measured by optical microscopy, SEM, or TEM, can be less than 150 micrometers, for example, less than 30 micrometers, less than 20 micrometers, less than 10 micrometers, less than 5 micrometers, or less than 2 micrometers, all measured by optical microscopy, SEM, or TEM. The width of the flake-like pigment, as measured by optical microscopy, SEM, or TEM, can be greater than 1 micrometer, 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 width of the flake pigment can range from 1 to 150 micrometers, for example, from 5 to 30 micrometers or from 10 to 15 micrometers, all measured by optical microscopy, SEM or TEM.

[0054] Flake pigments can include rounded edges, smooth and flat surfaces, angular edges, and / or uneven surfaces. Flake pigments comprising flake particles with angular edges and / or uneven surfaces are referred to in the art as "cornflakes." Flake pigments comprising flake particles distinguished by more rounded edges, smoother surfaces, and flatter surfaces are referred to as "silver dollar" flakes. Flake pigments can include coatings applied thereon, such as silicon dioxide-coated copper flakes. Conductive pigments can be flake pigments. Radar-transmitting pigments can be flake pigments. Flake pigments can be mixtures of both conductive and radar-transmitting pigments.

[0055] Based on the total area coverage of RT coating 104, the area coverage of the flake pigment in RT coating 104 of RT coating system 100 can be 30% or greater, for example, 35% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater, or 95% or greater, all based on the total area coverage of RT coating 104. Based on the total area coverage of RT coating 104, the area coverage of the flake pigment in RT coating 104 of RT coating system 100 can be 99% or lower, for example, 95% or lower, 90% or lower, 80% or lower, 70% or lower, 60% or lower, 50% or lower, 40% or lower, or 35% or lower, all based on the total area coverage of RT coating 104. The area coverage of the flake pigment in the RT coating 104 of the RT coating system 100 can be in the range of 30% to 99%, for example, 50% to 99%, 50% to 70% or 70% to 99%, all based on the total area coverage of the RT coating 104.

[0056] As reported herein, the area coverage of the flake-like pigment in RT coating 104 was determined using a Keyence VK-X260K / X250K confocal laser scanning microscope in transparent film mode with a 50x objective lens and RT coating 104 with a thickness ranging from 5 µm to 20 µm. As reported herein, the area coverage of the flake-like pigment in RT coating 104 was 12.7 µm when measured. Height maps were output from the confocal laser scanning microscope measurements, and the height range thresholds of the height maps were adjusted until the flake-like pigment was separated (e.g., areas where the flake-like pigment was present were blue and all other areas where the flake-like pigment was absent were black). The adjusted heightmap was loaded into ImageJ analysis software (available from the National Institutes of Health, Bethesda, Maryland, https: / / imagej.nih.gov / ij / ) and binarized to produce a black and white image where areas with plaque pigment are one color (e.g., black or white) and all other areas without plaque pigment are the opposite color. The area coverage of the plaque pigment in RT coating 104, as reported herein, was calculated based on the area covered by the color representing the plaque pigment in the binarized image in ImageJ analysis software, according to the total coverage area of ​​both colors.

[0057] A typical coating system having a coating comprising a pigment composition consisting of aluminum flakes may have a desired aesthetic appearance but may not require a reduction in radio waves passing through the typical coating system. The pigment composition in RT coating 104 can affect the aesthetic appearance of RT coating system 100 and / or the transmission of radio waves through RT coating system 100. Therefore, it may be desirable to minimize the CIELAB color difference (ΔE) of RT coating system 100 compared to a color-matching coating system while maintaining the desired transmission of radio waves through RT coating system 100. As used herein, the phrase "color-matching coating system" refers to a reference coating system that includes a coating composition for a coating comprising a flake-like pigment composition consisting of aluminum flakes. For example, the difference between RT coating system 100 and a reference color-matching coating system could be the amount of aluminum flakes present in the flake-like pigment composition of each respective system, if any.

[0058] The ΔE values ​​reported in this paper were measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer, specifically by BYKmac i. ΔE is based on the acquired values ​​according to Equation 3. , and The difference between two colors in the CIELAB color space.

[0059] Equation 3

[0060]

[0061] The ΔE measurements reported herein are determined based on a coating system comprising a substrate, a primer layer, a coating layer, and a clear coat. When compared to a color-matched coating system, the ΔE of the RT coating system 100 can be 15 or less, as 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 as measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 can be 3 or greater, as 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 as measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared with a color-matched coating system, the ΔE of the RT coating system 100 can be in the range of 3 to 15, as 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, all as measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0062] When compared to a color-matched coating system, the ΔE of the RT coating system 100 can be 6 or less, as 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 as measured at 25° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 can be 1 or greater, as 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 as measured at 25° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 compared to the color-matched coating system can be in the range of 1 to 6, as measured at 25° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as in the ranges of 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, all as measured at 25° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0063] When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 5 or less, as 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 as measured at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 1 or greater, as 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 as measured at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared with a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be in the range of 1 to 5, as measured at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as in the range of 1 to 2, 1 to 3, 1 to 4, 2 to 3, 2 to 4, 2 to 5, 3 to 4, 3 to 5, or 4 to 5, all as measured at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0064] When compared to a color-matched coating system, the ΔE of the RT coating 100 of this disclosure can be 5 or less, as 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 as measured at 75° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 1 or greater, as 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 as measured at 75° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared with a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be in the range of 1 to 5, as measured at 75° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as in the range of 1 to 2, 1 to 3, 1 to 4, 2 to 3, 2 to 4, 2 to 5, 3 to 4, 3 to 5, or 4 to 5, all as measured at 75° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0065] When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 4 or less, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, such as 3 or less, or 2 or less, or 1 or less, all as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 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. When compared with a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be in the range of 0.5 to 4, as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer, as in the range of 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 as measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

[0066] When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 7 or less, as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°, or as 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less, all as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°. When compared to a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be 1 or greater, as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°, or 2 or greater, 3 or greater, 4 or greater, 5 or greater, or 6 or greater, all as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°. When compared with a color-matched coating system, the ΔE of the RT coating system 100 of this disclosure can be in the range of 1 to 7, as measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°, as in the range of 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 measured using a multi-angle spectrophotometer with D65 illumination and a 10° observer based on the average values ​​of measurements at 15°, 25°, 45°, 75°, and 110°.

[0067] The primer layer 106 can be positioned adjacent to the RT coating 104. Compared to a color-matched coating system, the primer layer 106 can reduce the ΔE of the RT coating system 100. For example, the primer layer 106 can be opaque and can mask the color of the substrate 102 (e.g., the primer layer 106 can be opaque). The primer layer 106 may not contain effect pigments, such as reflective pigments, refractive pigments, specular pigments, or iridescent pigments. The CIELAB value of the primer layer 106, as measured using an integrating sphere spectrophotometer including D65 illumination, a 10° observer, and a mirror assembly, is significant. Values ​​can be 40 or less, such as 38 or less, 36 or less, 34 or less, or 32 or less, all measured using an integrating sphere spectrophotometer with D65 illumination, a 10° observer, and a mirror assembly. For example, measurements of primer layer 106 using an integrating sphere spectrophotometer with D65 illumination, a 10° observer, and a mirror assembly are possible. Values ​​can be 30 or greater, such as 32 or greater, 34 or greater, 36 or greater, or 38 or greater, all measured using an integrating sphere spectrophotometer with D65 illumination, a 10° observer, and a mirror assembly. For example, measurements using an integrating sphere spectrophotometer with D65 illumination, a 10° observer, and a mirror assembly for primer layer 106 (CIELAB) Values ​​can be 30 or 40, such as 30 to 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, or 34 to 36, all measured using an integrating sphere spectrophotometer including D65 illumination, a 10° observer, and a mirror assembly. Measurements of primer layer 106, as reported herein, were determined using a primer layer applied over substrate 102.

[0068] RT coating 104 can be applied by an RT coating composition comprising a film-forming resin and a pigment composition. The film-forming resin can be a resin that, upon removal of any diluent or carrier present with the film-forming resin or upon curing at ambient temperature or elevated temperatures, can form a self-supporting continuous film on the substrate 102 or other sublayers. The film-forming resin can include any resin used in the following categories: automotive OEM coating compositions, automotive repair compositions, industrial coating compositions, architectural coating compositions, coil coating compositions, packaging coating compositions, marine coating compositions, and aerospace coating compositions, etc. Film-forming resin refers to self-crosslinking resins, resins that are crosslinked by reaction with a crosslinking agent, mixtures thereof, etc. In other words, "film-forming resin" can therefore include both a resin and a crosslinking agent.

[0069] Film-forming resins can include thermosetting film-forming resins, thermoplastic film-forming resins, or combinations thereof. As used herein, the term "thermosetting" refers to a resin that irreversibly "solidifies" upon curing or crosslinking, wherein the polymer chains of the polymer components are covalently linked together, the curing or crosslinking typically caused by, for example, heat or radiation. The curing or crosslinking reaction can also occur under ambient conditions or at high temperatures. Once cured or crosslinked, thermosetting film-forming resins may not melt upon application of heat and may be insoluble in common solvents. As used herein, the term "thermoplastic" refers to a resin comprising polymer components not covalently linked and thus capable of undergoing liquid flow upon heating and soluble in common solvents.

[0070] Thermosetting coating compositions may include crosslinking agents selected from, for example, amino plastics, polyisocyanates containing terminal isocyanates, polyepoxides, β-hydroxyalkylamides, polybasic acids, acid anhydrides, organometallic acid functional materials, polyamines, polyamides, and mixtures of any of the foregoing substances.

[0071] The film-forming resin may have functional groups that are reactive with the crosslinking agent. The film-forming resin in the coating described herein may be selected from any polymer of various polymers well known in the art. The film-forming resin may be selected, for example, acrylic polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, polysiloxane polymers, copolymers thereof, and mixtures thereof. Typically, these polymers may be any polymer of these types prepared by any method known to those skilled in the art. The functional groups on the film-forming resin may be selected from any reactive functional group of various reactive functional groups, including, for example, carboxylic acid groups, amino groups, epoxy groups, hydroxyl groups, mercapto groups, urethane groups, amide groups, urea groups, isocyanate groups (including terminally capped isocyanate groups), thiols, and combinations thereof.

[0072] A method for preparing a RT coating includes combining a film-forming resin with a pigment composition to form an RT coating 104 with a dynamic index of 2 or greater. A dynamic index of 2 or greater can be achieved by formulating the pigment composition according to this disclosure. The RT coating may include greater than 70%, such as greater than 80%, of radar transmittance.

[0073] A method for applying a coating system to a substrate includes applying an RT coating composition onto at least a portion of a substrate 102 to form an RT coating 104. The RT coating composition can be applied by spraying, spin coating, dip coating, roll coating, flow coating, film coating, or a combination thereof. After applying the RT coating composition onto the substrate 102, the RT coating composition can be agglomerated to form a substantially continuous film on the substrate 102, and the RT coating composition can be cured to form the RT coating 104. The RT coating composition can be cured at a temperature of -10°C or higher, such as 10°C or higher. The RT coating composition can be cured at a temperature of 175°C or lower, such as 100°C or lower. The RT coating composition can be cured at a temperature in the range of -10°C to 175°C. Curing can include hot baking in an oven. Additional layers, such as a top coat 108, a primer layer 106, and combinations thereof, can be applied before or after the RT coating 104. In various examples, the RT coating 104 can be manufactured as a pre-formed film and subsequently applied to the substrate. For example, a coating composition can be applied to a substrate, cured, and subsequently removed from the substrate as a pre-formed film. A release agent may or may not be used to facilitate the release of the pre-formed film from the substrate.

[0074] Example

[0075] This disclosure will be more fully understood by referring to the following examples, which provide illustrative and non-limiting aspects of the invention. It should be understood that the invention described in this specification is not necessarily limited to the examples described in this section.

[0076] As used herein, unless otherwise indicated, the term “part” refers to a part by weight.

[0077] Example 1 - Polyethylene Dispersion

[0078] AC® 629 oxidized polyethylene was purchased from Honeywell. To prepare the polyethylene dispersion, 219.59 lbs ("lbs") of xylene was charged into a can. With the mixer open, 146.25 lbs of AC® 629 oxidized polyethylene was added to the can and nitrogen injection was applied. The material in the can was heated to 170°F and held until dissolved. The material in the can was then cooled to 160°F and held for 30 minutes, after which 365.98 lbs of xylene was added. The material in the can was then held at 120°F for 30 minutes to form the polyethylene dispersion.

[0079] Example 2 - Anti-sinking intermediate

[0080] Claytone 546 was purchased from BYK Additives and Instruments. 49.54 lbs of polyethylene dispersion from Example 1 was premixed in a container with 362.07 lbs of n-butyl acetate and 300.68 lbs of acrylic grinding carrier under Cowles stirring for 45 minutes. The acrylic grinding carrier consisted of 1% tert-dodecyl mercaptan, 1% inhibited icing acrylic acid, 10% hydroxyethyl 2-acrylate, 19% n-butyl methacrylate, 2% methacrylic acid, 20% ethylhexyl 2-acrylate, 18% methyl methacrylate, and 29% styrene, prepared at 53% by weight solids from a 22% isobutanol / 67% VM&P-free naphtha / 11% n-butyl acetate solvent mixture. 61.93 lbs of Claytone 546 was added to the container and mixed at high speed for 60 minutes using Cowles blades. The material was then milled on a horizontal mill with 1 mm media for two hours to produce an anti-settling intermediate.

[0081] Example 3 - Primer Preparation

[0082] The components listed in Table 1 are added sequentially from the top of Table 1 while being mixed at a low speed to form the primer. Common solvent-based colorants (e.g., carbon black, pigment blue 60, white TiO2, pigment blue 15:2, pigment violet 29) are used to prepare the primer.

[0083] Table 1 - Primer Components

[0084]

[0085] 1 Preparation as described in Example 1 of U.S. Patent 5,212,273.

[0086] 2 Acrylic polyol A is composed of 18% n-butyl methacrylate, 40% hydroxypropyl acrylate, 1% methyl methacrylate, 20% styrene, 19% n-butyl acrylate, and 2% glacial acrylic acid, prepared in a 58% methyl ether propylene glycol acetate / 39% aromatic 100 / 3% acetone solvent mixture with a GPC weight-average molecular weight of 8600 and an acid value of 10.6 as 67% by weight solids.

[0087] 3 Acrylic polyol B is composed of 1% tert-dodecyl mercaptan, 10% hydroxyethyl 2-acrylate, 19% n-butyl methacrylate, 2% methacrylic acid, 20% ethylhexyl 2-acrylate, 18% methyl methacrylate, and 30% styrene, prepared in 51% by weight of a mixture of 22% isobutanol / 68% VM&P-free naphtha / 10% toluene solvent.

[0088] 4 Polyester A is composed of 8% adipic acid, 34% isophthalic acid, 16% E-caprolactone, 18% dimethyl-2,2-propanediol-1,3, 16% neopentyl glycol hydroxypentanoate and 8% trimethylolpropane, prepared in 71% by weight of solids in n-butyl acetate solvent.

[0089] 5 The phosphated epoxy resin polymer consists of 67% Eponex 1511 (Hexion Specialty Chemicals) and 85% phosphoric acid, prepared in 60% by weight of solids from a blend of 91% hexyl cellosolve and 9% deionized water solvent.

[0090] 6 Polyester B is composed of 59% Empol 1008 dimer acid (BASF), 17% neopentyl glycol, 18% cyclohexanediethanol-1,4 and 6% trimethylolpropane, prepared in 100% by weight solids.

[0091] Example 4 - Silver - Coating Mixture

[0092] The primer prepared in Example 3 was used to prepare silver coatings (“CC”), Silver CC 1, Silver CC 2, and Silver CC 3, as shown in Table 2, with various levels of aluminum flakes and mica. The components of Silver CC 1-3 listed in Table 2 were combined and thoroughly mixed to produce Silver CC 1-3. The compositions of Silver CC 1-3 are listed in Table 3 by weight percentage.

[0093] Table 2 - Silver CC Compositions

[0094]

[0095] 7 Aluminum paste 634A was purchased from Toyo Aluminium Co., Ltd.

[0096] 8 TSB 2044A aluminum paste was purchased from Toyo America.

[0097] 9 KT-7104 pearlescent mica was obtained from Kolortek Co., Ltd.

[0098] 10 Iriodin 9602 silver-grey mica was purchased from EMD Performance Materials.

[0099] Table 3 - By weight percentage of silver CC composition

[0100]

[0101] Example 5 - Coating system applied to panel

[0102] The CMPP3700 commercial tackifier, available from PPG Industries Inc., Pittsburgh, PA, was hand-sprayed to a 7 µm dry film thickness onto an automotive TPO panel (Lyondell Hasell Hifax TPO, Standard Plaque Inc.) measuring 4 inches wide, 12 inches long, and 0.118 inches thick. The tack-coated TPO panels were allowed to dry overnight under ambient conditions. CIELAB color of the TPO panels before and after tackifier application was measured using specular exclusion data from an X-rite Color i7800 integrating sphere spectrophotometer with D65 illumination and a 10° observation. The results are listed in Table 4.

[0103] Table 4: Color data for TPO panels and TPO panels coated with adhesion promoters

[0104]

[0105] The TPO panels coated with the adhesion promoter were then coated with Silver CC 1-3, prepared in Example 4, using a spray gun mounted on a Spraymation model 310881. The Spraymation was set to a traverse speed of 1,000 inches per minute, the spray gun was opened 20 times, and Silver CC 1-3 was applied to the respective panels in two coats with a total dry film thickness of 20 µm. The TPO panels coated with Silver CC 1-3 were then flash-treated under ambient conditions for two minutes and then baked at 80°C for five minutes. Then, with the spray gun opened 28 times, a commercially available TKU2000CS clear coating, available from PPG Industries, Pittsburgh, Pennsylvania, was applied at a traverse speed of 850 inches per minute to the TPO panels coated with Silver CC 1-3 in two coats with a total dry film thickness of 46 µm. Each panel was then subjected to ambient flash-treatment for 10 minutes and then baked at 141°C for 30 minutes to produce Silver Panel 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.

[0106] Example 6 - Measurement

[0107] The CIELAB color of the silver panels 1-3 prepared in Example 5 was measured at multiple angles using a BYK-mac i spectrophotometer. To determine the color difference between the control, i.e., silver panel 1, and the panels of the present invention, i.e., silver panels 2-3, the color of the silver panels 1-3 was measured using a BYK-mac i spectrophotometer with D65 illumination and a 10° observer. , and The color data for each silver panel 1-3 is listed in Tables 5-7. The dynamic index of silver panels 1-3 is calculated using Equation 1 and is listed in Table 5. The color difference value, ΔE, of silver panels 1-3 is calculated using Equation 3 and is listed in Table 8.

[0108] Table 5 - CIELAB Silver Panels 1-3 value

[0109]

[0110] Table 6 - CIELAB Silver Panels 1-3 value

[0111]

[0112] Table 7 - CIELAB Silver Panels 1-3 value

[0113]

[0114] Table 8 - Color difference values ​​for silver panels 1-3, i.e., ΔE

[0115]

[0116] Insertion loss of silver panels 1–3 was measured using the focused beam method of Compass Technology Group (Alpharetta, Georgia) according to the standard test method CTG-TM-0100-2018, available at: https: / / compasstech.com / wp-content / uploads / 2018 / 06 / CTG-Focused-Beam-Mesurement-System-Standard.pdf. Insertion loss measurements were performed over a radar range of 60 GHz to 90 GHz (3001 points) using a 1000 Hz IF bandwidth, no averaging factor, and a 0.5 nanosecond time-domain gate. Insertion loss was measured on a Copperhills 4220 network analyzer with a driven E-band module using the manufacturer's recommended power level.

[0117] Insertion loss was measured by passing a radio wave, including a frequency of 77 GHz, through a TPO panel, adhesive, silver coating, and clear coat. The insertion loss at 77 GHz is reported in decibels (“dB”) and converted to a transmission percentage using Equation 2. The results of the insertion loss measurements are listed in Table 9.

[0118] Table 9 - Insertion Loss and Transmission Percentage of Silver Panels 1-3

[0119]

[0120] As shown in Table 9, measured at 77 GHz according to CTG-TM-0100-2018, the radar signal transmittance of silver panel 2 is 14% higher than that of silver panel 1. Similarly, measured at 77 GHz according to CTG-TM-0100-2018, the radar signal transmittance of silver panel 3 is 22% higher than that of silver panel 1.

[0121] While examples show the use of pigment compositions comprising 41.5% by weight of aluminum flakes and 58.5% by weight of mica, and pigment compositions comprising 100% mica, it should be understood that RT coatings can include suitable ΔE and radar signal transmittance within the range of aluminum flakes and mica described herein.

[0122] Example 7 - Area Coverage

[0123] The area coverage of flake-like pigments (e.g., mica and aluminum flakes) in silver CC 1-3 cured on the silver panels 1-3 prepared in Example 5 was measured. The area coverage of the flake-like pigments in silver CC 1-3 cured on the silver panels 1-3 was determined using a Keyence VK-X260K / X250K confocal laser scanning microscope in transparent film mode with 50x objectives. The height map output from the microscope was adjusted to separate the flake-like pigments and binarized using ImageJ software to calculate the area coverage of the flake-like pigments in silver CC 1-3 cured on the silver panels 1-3. The results are listed in Table 10.

[0124] Table 10 - Area Coverage of Silver Panels 1-3

[0125]

[0126] As shown in Table 10, the area coverage of the flake pigments in the silver CC 1-3 cured on the silver panels 1-3 is sufficient to provide the desired color for the respective panels.

[0127] Example 8 - Another silver coating

[0128] The components listed in Table 11 are added sequentially from the top of Table 11 to produce a silver coating 4 (“Silver CC 4”) similar to the silver coating in Chinese Patent Application No. 201811630188.2 by Zhong-min et al. Components 1-7 are added while mixing with disperser (e.g., Cowles) blades until homogeneity is achieved, and then the remaining components are added while mixing with propeller mixing blades. Additionally, a control coating (“Silver CC 5”) is prepared in the same manner as Silver CC 4, except that the mica pigment is replaced with aluminum flakes of the same volume. The components listed in Table 12 are added sequentially from the top of Table 12 while mixing in the same manner as in Table 11 to produce Silver CC 5.

[0129] Table 11 - Silver CC 4 Blend

[0130]

[0131] Table 12 - Silver CC 5 Blend

[0132]

[0133] Subsequently, the TPO panel (Lyondell Basell HiFax TRC779X, 4 inches × 12 inches × 0.118 inches, available from Standard Plaque, Inc.) was cleaned with SXA-330 and coated with SU-4903 adhesion promoter, both from PPG Industries. The CIELAB color of the TPO panel after applying the adhesion promoter was measured using specular exclusion data from an X-rite Colori 7800 integrating sphere spectrophotometer with D65 illumination and a 10° observer. The results are listed in Table 13.

[0134] Table 13: Color data for TPO panels and TPO panels coated with adhesion promoters

[0135]

[0136] Then, some TPO panels coated with adhesion promoters were sprayed with Silver CC4 (“Silver Panel 4”) from Table 11, and other TPO panels coated with adhesion promoters were sprayed with Silver CC5 (“Silver Panel 5”) from Table 12. After both Silver CC4 and Silver CC5 were thinned, they were sprayed with DT870 (available from PPG Industries) at a volume ratio of 2:1 for either Silver CC4 or Silver CC5 to DT870. Additionally, Silver Panels 4 and 5 were coated with a DC4000 topcoat (available from PPG Industries) using DCH3085 hardener at a volume ratio of 4:1 for DC4000 to DCH3085.

[0137] To establish a control, specifically the color difference between silver panel 5 and silver panel 4, the color difference between silver panels 4 and 5 was measured using a BKY-mac i spectrophotometer with D65 illumination and a 10° observer. , and The color data for each silver panel 4-5 is listed in Tables 14-16. The dynamic index of silver panel 4-5 is calculated using Equation 1 and is listed in Table 14. The color difference value, ΔE, of silver panel 4-5 is calculated using Equation 3 and is listed in Table 17.

[0138] Table 14 - CIELAB Silver Panels 4–5 value

[0139]

[0140] Table 15 - CIELAB Silver Panels 4–5 value

[0141]

[0142] Table 16 - CIELAB Silver Panels 4–5 value

[0143]

[0144] Table 17 - Color difference values, or ΔE, for silver panels 4-5 using silver panel 5 as a color reference.

[0145]

[0146] Compared to some other angles, the color difference value, ΔE, of the silver coating at 15° and 110° may be more difficult to match. As shown in Table 17 above, the silver panel 4 has a color difference value, ΔE, greater than 25 at 15° and a color difference value, ΔE, greater than 16 at 110°, which may be undesirable in some applications.

[0147] Those skilled in the art will recognize that the compositions, articles, methods, and accompanying discussions described herein are used as examples to clarify concepts, and various configuration modifications are contemplated. Therefore, as used herein, the specific examples and accompanying discussions are intended to represent their more general categories. In general, the use of any specific example is intended to indicate the category of the examples, and the omission of specific components (e.g., operations), apparatus, and objects should not be considered limiting.

[0148] Regarding the appended claims, those skilled in the art will understand that the operations described herein can generally be performed in any order. Moreover, although various flows of operations are presented in sequence, it should be understood that the operations can be performed in other orders than those shown, or that the operations can be performed simultaneously. Examples of these alternative orders may include overlapping, interleaved, interrupted, reordered, ascending, preparatory, supplementary, simultaneous, inverted, or other varied orders, unless the context otherwise requires. Furthermore, terms such as “in response to,” “related to,” or other past tense adjectives are generally not intended to exclude such variations, unless the context otherwise requires.

[0149] Although various examples have been described herein, those skilled in the art can implement and conceive of many modifications, alterations, substitutions, changes, and equivalents of these examples. Furthermore, where materials containing certain components are disclosed, other materials may be used. Therefore, it should be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations falling within the scope of the disclosed examples. The following claims are intended to cover all such modifications and variations.

[0150] This specification describes various features and characteristics to provide an understanding of the composition, structure, production, function, and / or operation of the disclosed compositions, coatings, and methods of the present invention. It should be understood that the various features and characteristics of the invention described herein can be combined in any suitable manner, whether or not such features and characteristics are explicitly combined in this specification. The inventors and the applicant expressly intend that such combinations of features and characteristics be included within the scope of the invention described herein. Thus, the claims may be amended to state any feature and characteristic explicitly or inherently described in this specification or otherwise explicitly or inherently supported by this specification in any combination. Furthermore, the applicant reserves the right to amend the claims to explicitly waive features and characteristics that may exist in the prior art, even if such features and characteristics are not explicitly described in this specification. Therefore, any such amendment will not add anything new to the specification or claims and will comply with the requirements of written description, sufficiency of description, and additional matters.

[0151] Any numerical range described in this specification describes all subranges containing the same numerical precision (i.e., having the same number of specified digits) within the described range. For example, the described range "1.0 to 10.0" describes all subranges between (and inclusive of) the described minimum value of 1.0 and the described maximum value of 10.0, such as "2.4 to 7.6," even though the range "2.4 to 7.6" is not explicitly described in the text of this specification. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly describe any subranges containing the same numerical precision within the ranges explicitly described in this specification. All such ranges are inherently described in this specification such that any modifications used to explicitly describe any such subranges will meet the requirements of written description, sufficiency of description, and additional matters.

[0152] Furthermore, unless the context explicitly indicates otherwise, all numerical parameters described in this specification (such as those expressing values, ranges, quantities, percentages, etc.) may be read as if prefixed with the word "about," even if the word "about" does not explicitly appear before the number. Additionally, the numerical parameters described in this specification should be interpreted based on the number of significant figures reported, the numerical precision, and the application of common rounding techniques. It should also be understood that the numerical parameters described in this specification necessarily possess the inherent variability of the underlying measurement techniques used to determine the values ​​of the parameters.

[0153] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​described in the specific examples are reported as precisely as possible. However, any numerical value inherently contains a certain degree of error, which must be caused by the standard deviation found in their respective test measurements.

[0154] The invention described herein may include, consist of, or substantially consist of the various features and characteristics described herein. The terms “comprise” (and any form of inclusion, such as “comprises” and “comprising”), “have” (and any form of having, such as “has” and “having”), “include” (and any form of inclusion, such as “includes” and “including”), and “contain” (and any form of containing, such as “contains” and “containing”) are open-ended connecting verbs. Therefore, a composition, coating, or method that “comprises,” “have,” “includes,” or “contains” one or more features and / or characteristics has, but is not limited to, having only, said features or / or characteristics. Similarly, elements of a composition, coating, or process that "comprises," "has," "includes," or "contains" one or more features and / or characteristics have said features or these features and / or characteristics, but are not limited to having only said features or these features and / or characteristics, and may have additional features and / or characteristics.

[0155] Unless otherwise stated, the grammatical articles “a,” “an,” and “the” used in this specification (including the claims) are intended to include “at least one” or “one or more.” Therefore, these articles are used in this specification to refer to one or more (i.e., to “at least one”) grammatical objects of the article. For example, “component” means one or more components, and therefore envisions that more than one component may be employed or used in embodiments of the described compositions, coatings, and processes. However, it should be understood that in some cases (but not others), the use of the terms “at least one” or “one or more” does not lead to the interpretation that the objects of the grammatical articles “a,” “an,” and “the” cannot be limited to only one. Furthermore, unless the context requires otherwise, the use of singular nouns includes plural nouns, and the use of plural nouns includes singular nouns.

[0156] Unless otherwise stated, any patent, publication, or other document identified in this specification is incorporated herein by reference in its entirety, but only to the extent that the incorporated material does not conflict with any existing descriptions, definitions, statements, descriptions, or other disclosures expressly set forth in this specification. Thus, and to the extent necessary, any conflicting material incorporated by reference shall supersede any express disclosure set forth in this specification. Any material, or part thereof, incorporated by reference in this specification that conflicts with any existing definitions, statements, or other disclosures set forth herein is incorporated only to the extent that such incorporated material does not conflict with any existing disclosure. The applicant reserves the right to amend this specification to expressly describe any subject matter, or part thereof, incorporated by reference. Amendments to this specification to add such incorporated subject matter shall comply with the requirements of written description, sufficiency of description, and additional matters.

[0157] Although specific examples of the invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that many detailed changes may be made to the invention without departing from the invention as defined in the appended claims.

[0158] While this disclosure provides a description of various specific aspects for the purpose of illustrating various aspects of this disclosure and / or its potential applications, it should be understood that variations and modifications will occur to those skilled in the art. Therefore, one or more inventions described herein should be understood as being at least as broad as the claims made thereto, and not as narrow as defined by the specific illustrative aspects provided herein.

Claims

1. A multilayer radar-transmitting coating system, comprising: Top coating; Optional primer layer; A silver radar-transmitting layer is provided adjacent to the primer layer, wherein the radar-transmitting layer comprises: Film-forming resins; and A flake pigment composition, the flake pigment composition comprising: Based on the total weight of the said flake pigment composition, 50% to 100% by weight of non-conductive radar-transmitting flake pigment; and Based on the total weight of the flake pigment composition, 0% to 50% by weight of conductive pigment; When the radar-transmitting layer is applied to a thermoplastic polyolefin substrate and cured with a dry film thickness of 20 µm to form the radar-transmitting layer: The radar-transmitting layer allows 70% or more of electromagnetic radiation, ranging from 1 GHz to 100 GHz, as determined by measured insertion loss, to be transmitted through the coating system; and The dynamic index of the radar transmissive layer is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And among them L1 is a CIELAB measurement taken at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. value, L2 is a CIELAB measurement taken at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. Value, and L3 is a CIELAB measurement taken at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. Value, and The CIELAB ΔE of the radar transmissivity layer is 4 or less compared to the color-matched coating system, measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

2. The multilayer radar-transmitting coating system according to claim 1, wherein the primer layer CIELAB Values ​​in the range of 30 to 40 were measured using an integrating sphere spectrophotometer that included D65 illumination, a 10° observer, and a mirror assembly.

3. The multilayer radar-transmitting coating system according to claim 1, wherein the pigment composition comprises 45% by weight or less conductive pigment based on the total weight of the pigment composition.

4. The multilayer radar-transmitting coating system according to claim 1, wherein the conductive pigment is an aluminum sheet.

5. The multilayer radar-transmitting coating system according to claim 1, wherein the pigment composition comprises 1% to 50% by weight of conductive pigment.

6. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the radar-transmitting pigment comprises visible light diffractive pigment, visible light reflective organic pigment, or a combination thereof.

7. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the radar-transmitting pigment comprises mica pigment, metal oxide flakes, or a combination thereof.

8. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the radar-transmitting pigment comprises an oxide-coated mica pigment.

9. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the radar-transmitting pigment comprises a glass sheet.

10. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the radar-transmitting pigment comprises an oxide-coated glass sheet.

11. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the coating system allows 70% or more of electromagnetic radiation with frequencies ranging from 1 GHz to 100 GHz to be transmitted through the coating system.

12. The multilayer radar transmissive coating system according to any one of claims 1-5, wherein the CIELAB ΔE of the coating system compared to the color-matched coating system is 15 or less, measured at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer.

13. The multilayer radar-transmitting coating system according to any one of claims 1-5, wherein the average particle size of the pigment composition is from 1 µm to 100 µm.

14. A coating formed from a multilayer radar-transmitting coating system according to any one of claims 1-13.

15. The coating of claim 14, wherein the dry film thickness of the coating is from 5 µm to 100 µm.

16. A coating system comprising: The coating according to any one of claims 14-15 is applied to a radar-transmitting substrate.

17. The coating system of claim 16, wherein the substrate comprises at least a portion of a vehicle assembly.

18. The coating system of claim 17, further comprising a radar system positioned near and / or adjacent to the radar-transmitting coating system.

19. The coating system of claim 16, wherein the area coverage of the flake pigment in the coating of the coating system is 30% to 99% based on the total area coverage of the coating.

20. The coating system of claim 16, wherein the area coverage of the flake pigment in the coating of the coating system is 50% to 99% based on the total area coverage of the coating.

21. A method for preparing the coating system according to claim 16, the method comprising: The film-forming resin is combined with the flake pigment composition to form the radar transmissive layer or RT layer coating composition; as well as The coating composition is applied and cured to form the coating.

22. The method of claim 21, further comprising applying the coating composition onto the substrate and curing the coating composition on the substrate.

23. The method of claim 22, further comprising: The coating composition is applied to the surface; The coating composition is cured to form a film on the surface; Remove the film from the surface to produce a pre-formed film; as well as The pre-formed film is applied onto the substrate.

24. The method according to any one of claims 22-23, further comprising applying a topcoat composition onto the coating after the coating is formed.

25. A coating composition having a silver color, comprising: Film-forming resin, wherein the film-forming resin comprises: Crosslinking agent; and Resins that are cross-linked by reacting with cross-linking agents; and A flake pigment composition, the flake pigment composition comprising: Based on the total weight of the said flake pigment composition, 50% to 100% by weight of non-conductive radar-transmitting flake pigment; and Based on the total weight of the said flake pigment composition, 0% to 50% by weight of conductive flake pigment; in: When the coating composition is applied to a thermoplastic polyolefin substrate and cured to form a coating system with a dry film thickness of 20 µm: The coating system allows 70% or more of electromagnetic radiation, measured by insertion loss, at frequencies ranging from 1 GHz to 100 GHz, to be transmitted through it; and The dynamic index of the coating system is 2 or greater, wherein the dynamic index = 2.69 (L1-L3). 1.11 / (L2) 0.86 And among them L1 is a CIELAB measurement taken at 15° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. value, L2 is a CIELAB measurement taken at 45° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. Value, and L3 is a CIELAB measurement taken at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. Value, and The CIELAB ΔE of the coating system compared to the color-matched coating system is 4 or less, measured at 110° using a multi-angle spectrophotometer with D65 illumination and a 10° observer. When the coating composition is applied to a thermoplastic polyolefin substrate and cured to a dry film thickness of 12.7 µm to form a second coating system, the area coverage of the flake pigments in the coating of the second coating system is 50% to 99% based on the total area coverage of the coating of the second coating system.

26. The coating composition of claim 25, wherein the pigment composition comprises 1% to 50% by weight of aluminum flakes based on the total weight of the pigment composition.

Images