Coating systems, films, and articles for radar transparency, methods of making and using the same

Abstract

Coating systems, films, and articles having a metallic luster, and methods of making and using the same, are provided. The coating systems include a first layer and a second layer disposed on at least a portion of the first layer. The first layer includes a first film-forming resin and a first pigment. The first layer has a CIELAB L* value of no greater than 10. The second layer includes a second film-forming resin, which is the same as or different from the first film-forming resin, and a flaky pigment. The second layer has a contrast ratio of no greater than 0.80. The coating system has a goniochromatic index of 19 or greater, for example, 20 or greater, 21 or greater, 22 or greater, 23 or greater, 24 or greater, 25 or greater, or 26 or greater.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 272,784, filed October 28, 2021, entitled “Coating Systems, Films, and Articles for Radar Transmission, Methods of Manufacturing and Use,” the entire contents of which are hereby incorporated by reference. Technical Field

[0003] Provides coating systems, films, and articles for radar transmission, as well as methods for their manufacture and use. Background Technology

[0004] The use of radar has become ubiquitous in modern transportation, including buses equipped with advanced driver assistance systems (ADAS) such as adaptive cruise control (ACC) and automatic braking. As autonomous driving technologies further develop, radar usage is likely to increase. Metallic pigments (such as aluminum flakes) are commonly used in coatings to achieve certain desired aesthetic properties, such as gloss, shimmer, and / or metallic color. However, radar signals may suffer from loss due to the use of metallic pigments, thus affecting radar performance. Summary of the Invention

[0005] This disclosure relates to a coating system comprising a first layer and a second layer disposed on at least a portion of the first layer. The first layer comprises a first film-forming resin and a first pigment. The first layer, as measured by an integrating sphere spectrophotometer using a D65 light source, a 10° observer, and excluding the specular reflection component (SCE), shows a CIELAB L... The value is not greater than 10, for example, not greater than 8, not greater than 6, not greater than 5, not greater than 3, or not greater than 2. The second layer comprises a second film-forming resin that is the same as or different from the first film-forming resin and flake pigments. When measured using an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and including a specular reflection component, the contrast of the second layer is not greater than 0.80, for example, not greater than 0.70, not greater than 0.60, not greater than 0.50, not greater than 0.40, or not greater than 0.38. When measured using a multi-angle spectrophotometer with a D65 light source and a 10° observer according to the following equation, the angle-dependent colorimetric index of the coating system is 19 or greater, for example, 20 or greater, 21 or greater, 22 or greater, 23 or greater, 24 or greater, 25 or greater, or 26 or greater:

[0006] Different color index with angle = 2.69 (L) 15 -L 110 ) 1.11 / (L 45 ) 0.86

[0007] in:

[0008] L 15 CIE L was measured at a non-mirror angle of 15°. value;

[0009] L 45 CIE L was measured at a non-mirror angle of 45°. Value; and

[0010] L 110 CIE L was measured at a non-mirror angle of 110°. value.

[0011] It is understood that this disclosure is not limited to the examples summarized in the content of this invention. Various other aspects are described and illustrated herein. Detailed Implementation

[0012] This disclosure relates to coating systems, films, and articles for radar transmission, having desired appearance properties such as gloss, shimmer, anisochromatic index (ACI), and / or metallic color. Metallic pigments (e.g., aluminum flakes) are commonly used in coatings as effect pigments to achieve desired gloss, shimmer, ACI, and / or metallic color. However, the use of metallic effect pigments in coatings results in a loss of radar transmittance. Furthermore, removing metallic pigments can increase the radar transmittance of the coating, but at the cost of losing the desired gloss, shimmer, ACI, and / or metallic color. Therefore, this disclosure provides a coating composition that achieves the desired gloss, shimmer, ACI, and / or metallic color through a coating comprising pigment, with minimal (if any) loss of radar transmittance. The coating composition according to this disclosure comprises a first layer and a second layer. The first layer comprises a film-forming resin, a first pigment, and no more than 10 ppm of CIELAB L. The values, such as those measured by an integrating sphere spectrophotometer using a D65 light source, a 10° observer, and SCE, are given. The second layer comprises a film-forming resin, flake pigments, and a contrast ratio not exceeding 0.80. The angular heterochromaticity index of this coating system is 19 or greater.

[0013] The luminance values ​​of the coating can be measured and quantified from various angles, using the International Commission on Illumination (CIE) standards discussed here. CIELAB L values ​​the use of coating systems, films and / or articles The value should be reported. (CIE L) a b (CIELAB) Color values ​​can be measured using a multi-angle spectrophotometer, such as the BYKmac I from Altana, at angles of 15°, 25°, 45°, 75°, and / or 110° relative to the mirror direction, using a D65 light source and a 10° observer. As used herein, L 15 This refers to L at a measurement angle of 15°. Brightness value, L 25 This refers to L at a measurement angle of 25°. Brightness value, L 45 This refers to L at a measurement angle of 45°. Brightness value, L 75 This refers to L at a measurement angle of 75°. Brightness value, and L 110 This refers to L at a measurement angle of 110°. Brightness value. As used in this article, near-mirror brightness testing uses L. 15 The value is used to quantify the brightness of the coating, which can be measured using a multi-angle spectrophotometer (such as the BYKmac I from Altana) at a measurement angle of 15° relative to the mirror direction with a D65 light source and a 10° observer.

[0014] In other cases, the brightness value of the coating can be measured and quantified using an integrating sphere spectrophotometer, such as the X-rite CI7800, with a D65 light source and a 10° observer, including or excluding the specular component (SCI).

[0015] The coating composition according to this disclosure includes a first layer and a second layer. The first layer includes a film-forming resin, a first pigment, and no more than 10g of CIELAB L. The contrast ratio, as measured by an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and SCE, is given. The second layer comprises a second film-forming resin and flake pigments that are the same as or different from the film-forming resin used in the first layer. The contrast ratio of the second layer is not greater than 0.80, as measured by an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and including the specular reflection component.

[0016] Film-forming resins can include resins that, after physical drying and / or curing at room temperature or high temperature, remove any diluent or carrier to form a self-supporting (e.g., capable of maintaining as a material film with defined thickness, length, and width, and remaining so even in the absence of a supporting substrate) continuous film. As used herein, "film-forming resin" refers to self-crosslinking resins, resins that crosslink through reaction with a crosslinking agent, and resins that form a solid film through solvent evaporation, mixtures thereof, etc. The term "film-forming resin" can be collectively referred to as resins and their crosslinking agents.

[0017] Film-forming resins can include thermosetting film-forming resins and / or thermoplastic film-forming resins. 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 linked together by covalent bonds, typically induced, for example, by heating or radiation. In various instances, the curing or crosslinking reaction can be carried out under ambient conditions (e.g., approximately 20°C to 25°C and / or 1 atmosphere). Once cured or crosslinked, thermosetting film-forming resins may not melt upon heating and are insoluble in common solvents (e.g., less than 0.001 g of material is soluble in 1 g of a given solvent after 24 hours at 20°C). As used herein, the term "thermoplastic" refers to a resin comprising polymer components not linked by covalent bonds, thus capable of liquid flow upon heating, and soluble in common solvents (e.g., at least 0.1 g of the material is soluble in 1 g of a given solvent after 24 hours at 20°C).

[0018] Thermosetting coating compositions may include crosslinking agents selected from, for example, amino plastics, polyisocyanates (including terminated isocyanates), polyepoxides, β-hydroxyalkylamides, polybasic acids, acid anhydrides, organometallic acid functional materials, polyamines, polyamides, and mixtures of any of the foregoing.

[0019] 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 of a variety of polymers well known in the art. The film-forming resin may be selected from, for example, acrylic polymers, epoxy 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 of a variety of reactive functional groups, including, for example, carboxylic acid groups, amino groups, epoxy groups, hydroxyl groups, thiols, urethane groups, amide groups, urea groups, isocyanate groups (including terminal isocyanate groups), thiols, or combinations thereof.

[0020] The first pigment in the first layer can be radar-transmissive. As used herein, “radar-transmissive” means that the pigment, if any, suppresses the transmission of electromagnetic radiation at radar frequency wavelengths to a minimum.

[0021] The first pigment can be configured to achieve the desired dark color for the first layer. This dark color can be achieved through CIELAB L. The SCE and / or the blackness of the first layer are measured. For example, the first layer's CIELAB L, as measured by an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and an SCE. The SCE value may not exceed 10, for example, if measured by an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and an SCE value, it may not exceed 8, 6, 5, 3, or 2. If measured using a multi-angle spectrophotometer at 110° with a D65 light source and a 10° observer, the first layer may include a blackness of 350 or greater, for example, 360 or greater, 370 or greater, or 380 or greater if measured using a multi-angle spectrophotometer at 110° with a D65 light source and a 10° observer. Blackness can be measured according to Equation 12 from K. Lippok-Lohmer, “Praxisnahe Schwarzmessungen”, Farbe + Lack, 92 (1986) 1024-1029, which discloses blackness = 100 × {[log 10 (X n / X) + log 10 (Y n / Y) - log 10 (Z n This document is hereby incorporated by reference.

[0022] The first pigment can be a single pigment or a mixture of different pigments. The first pigment may include carbon black, iron oxide, perylene black, pigment blue 15:1, pigment blue 15:3, pigment brown 25, pigment red 101, pigment red 179, pigment red 202, pigment red 257, pigment red 264, pigment violet 19, pigment violet 29, pigment yellow 129, pigment yellow 139, pigment 150, pigment yellow 42, or combinations thereof. The first pigment may include nanoscale pigments with an average particle size less than 100 nm, for example less than 50 nm or less than 40 nm, as measured by transmission electron microscopy (TEM). As used herein, the average particle size measured by TEM refers to the Ferrette diameter of the particles as measured by TEM.

[0023] The first pigment may include a transmission haze of no more than 10%, as measured according to ASTM D1003, such as no more than 8%, no more than 4%, no more than 3%, no more than 2%, or no more than 1%, all of which are measured using a spectrophotometer (e.g., X-rite Ci7800) according to ASTM D1003. For example, to measure transmission haze, a suitable amount of the first pigment (e.g., 0.04 wt% based on the total weight of the dispersion) of the first layer can be dispersed and diluted in a suitable solvent (e.g., n-butyl acetate) and placed in the optics of a spectrophotometer. Transmission haze is a measure of electromagnetic radiation that is scattered at an angle greater than 2.5° at the maximum absorbance of the pigment in the visible wavelength range of 400 nm to 700 nm and has a transmission percentage of 15% to 20%, such as 17.5%. Transmission haze can be measured according to the transmission measurement procedures of U.S. Patent No. 6,875,800, filed June 7, 2002, which are hereby incorporated by reference.

[0024] Based on the total volume of the first layer formed by the first coating composition, the first coating composition and / or the first layer may include an amount of first pigment ranging from, for example, 0.5 vol% to 70 vol% (e.g., 1 vol% to 60 vol%).

[0025] A second layer of the coating system may be disposed on at least a portion of the first layer. The second layer may include a film-forming resin that is the same as or different from the film-forming resin of the first layer described herein, and a flake pigment. The flake pigment may be configured such that the second layer can be radar-transmissive. For example, because the flake pigment is significantly transparent to radar signals (e.g., transmitting 80% or more of electromagnetic radiation at frequencies from 1 GHz to 300 GHz), the second layer is also significantly transparent to radar signals.

[0026] As used herein, the term "flaky pigment" refers to a pigment in the form of a sheet, wherein the ratio of the width to the thickness of the pigment (called aspect ratio) is at least 5, for example, at least 6, at least 10, at least 100, at least 200, at least 500, or at least 1000. The aspect ratio of a flake pigment can be less than 2000, for example, less than 1000, less than 500, less than 200, less than 100, less than 10, or less than 6. The aspect ratio of a flake pigment can be in the range of 5 to 2000, for example, 5 to 1000, 10 to 2000, 10 to 200, or 20 to 500. The thickness of a flake pigment, as measured by TEM, can be less than 10 micrometers, for example, less than 5 micrometers, less than 0.5 micrometers, or less than 0.05 micrometers. The thickness of a flake pigment, as measured by TEM, can be greater than 0.05 micrometers, for example, greater than 0.5 micrometers, greater than 5 micrometers, or greater than 10 micrometers. The thickness of the flake pigment, as measured by TEM, can range from 0.05 μm to 10 μm, for example, 0.5 μm to 5 μm as measured by TEM. The width of the flake pigment, as measured by TEM, can be less than 150 μm, for example, less than 30 μm, less than 20 μm, less than 10 μm, less than 5 μm, or less than 2 μm as measured by TEM. The width of the flake pigment, as measured by TEM, can be greater than 1 μm, for example, greater than 2 μm, greater than 5 μm, greater than 10 μm, greater than 20 μm, greater than 30 μm, or greater than 150 μm as measured by TEM. The width of the flake pigment, as measured by TEM, can range from 1 μm to 150 μm, for example, 5 μm to 30 μm or 10 μm to 15 μm as measured by TEM.

[0027] The second layer of flake pigments can comprise a single pigment or a mixture of different pigments. Flake pigments can include, for example, mica pigments, oxide-coated mica pigments, glass flakes, oxide-coated glass flakes, visible light diffractive pigments, visible light reflective organic pigments, metal oxide lamellae, radar-transmitting composite pigments, 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 in U.S. Patent No. 6,894,086 to Munro et al. and the colorants described in U.S. Patent No. 8,133,938 to Munro et al. The descriptions of color effect pigments in U.S. Patent No. 6,894,086 to Munro et al. and the descriptions of colorants in U.S. Patent No. 8,133,938 to Munro et al. are hereby incorporated by reference. Visible light reflective organic pigments can comprise a polymer layer, such as the pigments described in U.S. Patent No. 6,299,979 to Neubauer et al., which is hereby incorporated by reference. Metal oxide lamellae can be, for example, alumina and titanium oxide. According to PCT / US2021 / 040877, filed July 8, 2021, entitled "RADAR TRANSMISSIVE PIGMENTS, COATINGS, FILMS, ARTICLES, METHODS OF MANUFACTURE THEREOF, AND METHODS OF USETHEREOF", radar transmissive composite pigments may include non-conductive composite materials. The description of non-conductive composite materials in PCT / US2021 / 040877 is hereby incorporated by reference. According to PCT / US2020 / 045430, filed August 7, 2020, entitled "COATING COMPOSITIONS, LAYERS, AND SYSTEMS FOR RADAR TRANSMISSION AND METHODS FOR MAKING AND USING THE SAME", flake pigments may include non-conductive pigments. The description of nonconductive pigments in PCT / US2020 / 045430 is hereby incorporated by reference. Based on the total volume of the second layer formed by the coating composition, the second coating composition and / or the second layer may comprise, for example, an amount of flake pigment from 0.5 vol% to 60 vol%, such as 1 vol% to 50 vol% or 2 vol% to 25 vol%.

[0028] As discussed below, due to the structure of the plate-like pigments, the second layer may not provide complete coverage. For example, plate-like pigments may be less opaque than similar metallic effect pigments. Therefore, when measured using an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and SCI, the contrast of the second layer may not exceed 0.80, for example, not exceeding 0.70, 0.60, 0.50, 0.40, or 0.38 when measured using an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and SCI.

[0029] Contrast ratio can be measured using a contrast ratio test. The contrast ratio test involves applying a coating, coating system, and / or film to a standard panel to measure the hiding power of the coating, coating system, and / or film (i.e., T12G METOPAC). TM The panel, 3×5×3 / 16 inches, is manufactured by Leneta Company, Inc. in Mahwah, New Jersey. The standard panel features an L... The black portion with a value of 26 (+ / -5%) and L The white portion with a value of 94 (+ / -5%) was measured using an integrating sphere spectrophotometer (e.g., X-Rite CI7800) with a D65 light source, a 10° observer, and an SCI. After coating the panel with the coating, coating system, and / or film to be measured for opacity, L was measured on the black and white portions of a standard panel using a multi-angle spectrophotometer, such as the BYKmac I multi-angle spectrophotometer, with a D65 light source and a 10° observer. 110 Then, the L measured on the black and white portions of a standard panel with a coating was determined. 110 The ratio of values ​​quantifies the contrast of the coating, coating system, and / or film. The equation for contrast is shown in Equation 1 below:

[0030] Equation 1:

[0031] Contrast = L 110 (On the black part of the panel) / L 110 (On the white part of the panel.)

[0032] The first pigment of the first layer can be incorporated into the first coating composition by grinding or simple mixing, and / or the flake pigment of the second layer can be incorporated into the second coating composition.

[0033] Compared to coating systems that fully incorporate conductive metallic effect pigments, the coating system according to this disclosure can provide the desired gloss, shimmer, angle-dependent colorimetric index, and / or metallic color, while minimizing radar transmittance reduction. These conductive metallic effect pigments are, for example, aluminum flakes, copper flakes, silver flakes, silver-plated copper flakes, nickel flakes, or other metal flakes. The resistivity of the coating system that fully incorporates conductive metallic effect pigments is significantly lower than that of the flake pigments of this disclosure, for example, by seven orders of magnitude (e.g., 10⁻⁶). -6 This can lead to high radar transmission loss (Ohm cm). Because the coating system according to this disclosure includes a large amount of radar-transmitting pigments, it is capable of effectively transmitting electromagnetic radiation, including radar frequency wavelengths. For example, the coating system according to this disclosure and / or films and / or articles incorporating the coating system can effectively transmit electromagnetic radiation in the wavelength range of 1 GHz to 300 GHz, such as 1 GHz to 100 GHz or 76 GHz to 81 GHz. The 76 to 81 GHz wavelength range can be used for automotive radar and other radar applications. The coating system according to this disclosure and / or films and / or articles incorporating the coating system can effectively transmit (e.g., be transparent to) electromagnetic radiation with wavelength frequencies of 24 GHz, 76 GHz, 77 GHz, and / or 81 GHz.

[0034] While reducing the concentration of conductive metallic effect pigments in the second layer can minimize the reduction in radar transmittance of the coating system, there is a risk that the gloss, glitter, angle-dependent anisochromatic index, and / or metallic color of the coating system may also be reduced. This is because other radar-transmitting pigments (e.g., mica) have inferior gloss, glitter, angle-dependent anisochromatic index, and / or metallic color compared to similar conductive metallic effect pigments. However, the L in the first layer... The combination of a value and / or blackness with a second layer that does not fully cover the surface can provide the desired gloss, brilliance, angle-dependent colorimetric index, and / or metallic color to the coating system of this disclosure. For example, the first layer may be a primer layer, and the second layer may be a base coat at least partially disposed on a portion of the primer layer. Therefore, since the base coat may not fully cover the surface, and the first layer includes a CIELAB L value of no more than 10, the coating system can achieve the desired gloss, brilliance, angle-dependent colorimetric index, and / or metallic color. With a blackness of 350 or greater, the coating system according to this disclosure can still maintain the desired gloss, shimmer, angle-dependent color index, and / or metallic color of similar coating systems with conductive metallic effect pigments.

[0035] The first coating composition, the second coating composition, the first layer, and / or the second layer may include other additives and / or additional pigments. For example, additives may include plasticizers, abrasion-resistant particles, film-reinforcing particles, flow control agents, thixotropic agents, rheology modifiers, cellulose acetate butyrate, catalysts, antioxidants, antimicrobial agents, defoamers, surfactants, wetting agents, dispersing agents, thickeners, clays, hindered amine light stabilizers, ultraviolet (UV) light absorbers and stabilizers, stabilizers, fillers, organic cosolvents, reactive diluents, abrasive carriers, and other conventional additives or combinations thereof.

[0036] The first coating composition and / or the second coating composition may be formulated as a solvent-based composition, a water-based composition, or a 100% solid (i.e., non-volatile) composition that does not contain a volatile solvent (e.g., readily evaporates at ambient temperature) or an aqueous carrier. Furthermore, the first coating composition and / or the second coating composition may be liquid 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 first coating composition and / or the second coating composition may be liquid 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. The first coating composition and / or the second coating composition may be liquid at temperatures ranging from -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 first coating composition and / or the second coating composition may be liquid at ambient temperatures (e.g., 20°C to 25°C).

[0037] The first coating composition and / or the second coating composition may be formulated to have a liquid viscosity suitable for atomization and droplet formation at temperatures of -10°C or higher under high shear conditions associated with single-component or multi-component spraying techniques, such as 0°C or higher, 10°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. The first coating composition and / or the second coating composition may be formulated to have a liquid viscosity suitable for atomization and droplet formation at temperatures of 60°C or lower under high shear conditions associated with single-component or multi-component spraying techniques, such as 50°C or lower, 40°C or lower, 30°C or lower, 10°C or lower, or 0°C or lower. The first coating composition and / or the second coating composition may be formulated to have a liquid viscosity suitable for atomization and droplet formation in the temperature range of -10°C to 60°C under high shear conditions associated with single-component or multi-component spraying techniques, such as -10°C to 50°C, -10°C to 40°C, -10°C to 30°C, or 10°C to 40°C. For example, the viscosity of a liquid suitable for atomization and droplet formation under the high shear conditions associated with single-component or multi-component spraying techniques would range from 50 centipoise (cP) to 500 cP, measured as follows: on a Brookfield CAP2000 with a #2 spindle at 900 RPM and 22°C. High shear conditions using single-component or multi-component spraying techniques can include shear applied by various spraying techniques, including bell nozzles, spray guns (including air spraying, airless spraying, and air-assisted airless spraying), etc. The shear rate for such spraying would be expected to be greater than 1000 sec. -1 The specific value will depend on the spraying technology used.

[0038] The coating system, the first layer, and / or the second layer may include no more than 2% by weight of conductive pigment (e.g., having at least 10%). 6 The bulk conductivity (S / m) is, for example, not greater than 1% by weight, not greater than 0.5% by weight, or not greater than 0.1% by weight. For example, the coating system, the first layer, and / or the second layer may not include conductive pigments. Conductive pigments may include conductive materials or a dielectric substrate (e.g., conductivity less than 10 S / m). -3The conductive pigment can be, for example, aluminum flakes, steel flakes, copper flakes, silver particles, conductive carbon pigments, or combinations thereof. For example, the first and / or second layers may include 2% by weight or less aluminum flakes, such as 1% by weight or less, 0.5% by weight or less, or 0.1% by weight or less of the total weight of the respective layers. The aluminum flakes may include aluminum paste 634A from Toyota Aluminum KK and / or TSB 2044A aluminum paste from Toyota America. Minimizing the amount of aluminum flakes in the coating system according to this disclosure can enable higher radar transmittance of the coating system.

[0039] The coating system according to this disclosure can transmit 80% or more of electromagnetic radiation with a frequency of 1 GHz to 100 GHz through the coating system, for example, 85% or more or 90% or more of electromagnetic radiation with a frequency of 1 GHz to 100 GHz through the coating system. The coating system according to this disclosure can transmit 80% or more of electromagnetic radiation with a frequency of 1 GHz to 100 GHz through the coating system, for example, 85% or more or 90% or more of electromagnetic radiation with a frequency of 76 GHz to 81 GHz through the coating system. The coating system according to this disclosure can transmit 80% or more of electromagnetic radiation with a frequency of 76 GHz to 81 GHz through the coating system, for example, 85% or more or 90% or more of electromagnetic radiation with a frequency of 76 GHz to 81 GHz through the coating system.

[0040] One-way radar transmission loss (OWRTL) can be quantified according to this disclosure for the radar loss (if any) of pigmented coatings, films, and / or articles. OOWRTL can be measured in dB using radar testing with a radar transmission system, such as a focused beam radar measurement system assembled from the following components: a signal generator (SMA100B (equipped with SMAB-B92 / SMAB-B120)) available from Rohde & Schwarz, a six-fold multiplier (SMZ90) available from Rohde & Schwarz, a thermal waveguide power sensor (NRP90TWG) available from Rohde & Schwarz, two E-band point-focusing lens antennas (SAQ-813017-12-S1) with a focal length of 1.7 inches available from Sage Millimeter, and a 3.5 mm plug-to-3.5 mm coaxial cable (FM160FLEX) available from Fairview Microwave. Two lenses are connected to the transmitter (a hex multiplier) and the detector (a power sensor), facing each other. The lenses are aligned along their axes with a spacing approximately twice their focal length (3.4 inches), adjusted to ensure maximum free-space radar transmittance. No sample is placed between the lenses. Using this setup, the sample can be measured by fixing it between the lenses, with the sample surface facing the detection lens positioned 45 mm away from the detection lens (1.8 mm in front of the detection lens's focal point). If the sample is a thermoplastic polyolefin (TPO) sheet with a coating or film, the OWRTL can be measured by fixing it between the lenses, with the surface of the coating or film being measured facing the detection lens, 45 mm away. Radar transmittance loss, in dB, is calculated using Equation 2.

[0041] Equation 2:

[0042] OWRTL (dB) = Free space transmittance (dBm) – Sample transmittance (dBm).

[0043] The coating systems, films, and / or articles according to this disclosure may include the desired radar transparency. For example, as measured by radar testing in the frequency range of 76 GHz to 81 GHz, the coating systems, films, and / or articles according to this disclosure may include an OWRTL of no more than 1.5 dB, such as all of which, as measured by radar testing, are no more than 1.3 dB, no more than 1.0 dB, no more than 0.7 dB, no more than 0.5 dB, or no more than 0.3 dB.

[0044] The coating system according to this disclosure can have desired appearances, such as gloss, shimmer, colorfastness index, and / or metallic color. For example, coatings, films, and / or articles incorporating pigments according to this disclosure can include 115 or greater L, as measured by a near-spectral brightness test. 15 Values, such as all those measured by near-mirror brightness tests, are 120 or greater, 125 or greater, or 130 or greater.

[0045] The metallic color of the coating system can be quantified according to the angle-dependent colorimetric index. For example, as measured by the angle-dependent colorimetric test, the angle-dependent colorimetric index of the coating system according to this disclosure can be 19 or greater, such as all of the following as measured by the angle-dependent colorimetric test: 20 or greater, 21 or greater, 22 or greater, 23 or greater, 24 or greater, 25 or greater, or 26 or greater.

[0046] The angle-dependent colorimetric index of a coating or film on a substrate or article can be determined using an angle-dependent colorimetric test. The angle-dependent colorimetric test can be performed using a multi-angle spectrophotometer (e.g., the BYKmac I spectrophotometer) with a D65 light source and a 10° observer, measured in the CIELAB color space by L... The angle-dependent colorimetric index is quantified. As used herein, the term "angle-dependent colorimetric index" is defined according to "Observation and Measurement of the Appearance of Metallic Materials - Part 1 - Macro Appearance," CSMcCamy, Color Research and Application, Vol. 21, No. 4, August 1996, pp. 292-304, which is hereby incorporated by reference. That is, the angle-dependent colorimetric index is defined according to Equation 3 listed below.

[0047] Equation 3

[0048] Different color index with angle = 2.69 (L) 15 -L 110 )1.11 / (L 45 0.86

[0049] in:

[0050] L 15 CIE L was measured at a non-mirror angle of 15°. value;

[0051] L 45 CIE L was measured at a non-mirror angle of 45°. Value; and

[0052] L 110 CIE L was measured at a non-mirror angle of 110°. value.

[0053] The dry film thickness (DFT) can be selected to provide the desired contrast and radar transmittance. For example, increasing the DFT can increase contrast. However, increasing the DFT can also increase OWRTL. The DFT of the coating system and / or film can range from 5 µm to 100 µm. The DFT selected for the coating system should be the same as that used in contrast testing, near-spectral brightness testing, angle-dependent color variation testing, and radar testing. The DFT of the coating and / or film can be measured using a coating thickness measurement tool, such as the FMP40C Dualscope (available from Fischer Technology, Inc.).

[0054] The first coating composition and / or the second coating composition can be, for example, an automotive original equipment manufacturer (OEM) coating composition, an automotive repair coating composition, an industrial coating composition, a building coating composition, a coil coating composition, a packaging coating composition, a marine coating composition, an aerospace coating composition, a consumer electronics coating composition, or a combination thereof. For example, the first coating composition and / or the second coating composition can be applied to automotive parts such as bumper panels, mirror housings, fenders, hoods, trunks, doors, etc., or to aerospace parts such as nose cones, radomes, etc.

[0055] A method of applying a coating system according to the present disclosure to a substrate includes depositing a first coating composition and a second coating composition on the substrate. Each coating composition can be deposited by at least one of spraying, spin coating, dip coating, roll coating, flow coating, and film coating. In various examples, the coating system can be manufactured as a pre-formed film and then applied to the substrate. After the coating compositions are deposited on the substrate, the coating compositions can coalesce on the substrate to form a continuous film. The first coating composition can be cured to form a first layer, and the second coating composition can be cured to form a second layer. The first coating composition can be cured before the second coating composition or both can be cured simultaneously. Each coating composition can be cured at a temperature of -10°C or higher, such as 10°C or higher. Each coating composition can be cured at a temperature of 175°C or lower, such as 100°C or lower. Each coating composition can be cured in a temperature range from -10°C to 175°C. Curing can include hot baking in an oven (e.g., 80°C or higher, 100°C or higher, 140°C or higher).

[0056] The flake pigments according to this disclosure can also be suitably incorporated into a film, which, when applied to an article, can provide desired optical properties, including imparting a metallic luster in the visible light wavelength range and / or providing desired radio frequency transparency, for example, at automotive radar frequencies. Films containing the pigments of this disclosure can be formed from any material in which a film suitable for application to a substrate is produced. Films according to this disclosure can be manufactured such that the film will have an appearance similar to a flake-containing coating with a “glittery” quality, rather than a mirror appearance. The pronounced “glittery” quality in a coating containing reflective effect pigments can be evaluated as described in “Complete Appearance Control for Effect Paint Systems” in the Paint & Coatings Industry, March 8, 2020. As described herein, the film can be applied to any substrate and can be used in combination with another film layer or coating.

[0057] The membrane can be a multilayer membrane comprising at least three layers, including a first layer, a second layer, and an adhesive layer. The adhesive layer may be protected with a removable layer or release liner that can be removed before the membrane is applied to the substrate. A first coating composition and / or a second composition may be applied to a carrier membrane supporting the coating composition until a coating system is formed, after which the carrier membrane may optionally be removed. The coating system may be applied to a transparent protective film, which itself may be on the carrier membrane. The transparent protective film may be thermosetting or thermoplastic, and it will be the top layer when the multilayer membrane is applied to the substrate via contact with the adhesive layer. The layers of the multilayer membrane may include thermosetting or thermoplastic polyurethane. Examples of such multilayer films and methods of manufacturing such films are described in U.S. Patent Publications 2011 / 0137006, 2017 / 0058151, 2014 / 322529, 2004 / 0039106, 2009 / 0186198, 2010 / 0059167, 2019 / 0161646, 5,114,789, 5,242,751, and 5,468,532, all of which are hereby incorporated by reference. The first layer of the film may be sprayed, extruded, formed, or polymerized in situ, or otherwise deposited onto adjacent or removable layers of the multilayer film.

[0058] The substrate may be at least partially coated with a coating system according to the present disclosure. For example, the coating system may be applied to 5% or more of the outer surface area of ​​the substrate, 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 ​​the substrate. The coating system according to the present disclosure may be applied to 100% or less of the outer surface area of ​​the substrate, 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 ​​the substrate. The coating system according to the present disclosure may be applied to 5% to 100% of the outer surface area of ​​the substrate, such as 5% to 99%, 5% to 90%, 5% to 70%, or 50% to 100% of the outer surface area of ​​the substrate.

[0059] This coating system can be incorporated into a multilayer coating stack, such as a multilayer coating stack comprising at least three coatings: a first layer, a second layer on at least a portion of the first layer, and a third layer. Additional layers, such as pretreatment layers, tackifier layers, base coats, intermediate coats, top coats (e.g., clear coats, colored clear coats), primer layers (e.g., non-conductive primer layers), or combinations thereof, can be deposited before or after the coating system according to this disclosure. Colored clear coats can be, for example, clear coats with added dyes and / or pigments, including nanoscale pigment dispersions described in U.S. Patent Nos. 6,875,800, 7,605,194, 7,612,124, and 7,981,505, all of which are hereby incorporated herein by reference. Colored clear coats can include nanoscale pigment dispersions, such as those measured by transmission electron microscopy (TEM), having an average primary particle size of less than 150 nm, for example, less than 100 nm as measured by TEM. Nanoscale pigment dispersions can have an average primary particle size of 20 nm to 150 nm, such as 20 nm to 100 nm, 20 nm to 80 nm, 20 nm to 60 nm, or 20 nm to 40 nm. For example, nanoscale pigment dispersions can have an average primary particle size of 25 nm, 35 nm, or 50 nm.

[0060] A coating stack for automotive applications may include a tackifier layer applied to a radar-transmitting substrate, a primer layer (e.g., a first layer) disposed on the tackifier layer, an undercoat layer (e.g., a second layer) disposed on the primer layer, and a clear coating layer disposed on the undercoat layer.

[0061] The coating systems and / or films disclosed herein can be applied to a variety of substrates that may require radar transparency and a metallic appearance. For example, substrates to which the coating systems and / or films of this disclosure can be applied include automotive substrates, industrial substrates, building substrates, roll-to-roll substrates, packaging substrates, marine substrates, aerospace substrates, consumer electronics substrates (e.g., telephones, computers, tablets), and combinations thereof. As used herein, “automotive” in its broadest sense refers to all types of vehicles, such as, but not limited to, cars, trucks, buses, tractors, harvesters, heavy equipment, vans, golf carts, motorcycles, bicycles, railcars, aircraft, helicopters, and ships of all sizes.

[0062] The substrate can be a radar-transmitting substrate, such as a non-metallic substrate. Non-metallic substrates can include polymers, such as plastics, including polyesters, polyolefins, polyamides, cellulose, polystyrene, polyacrylic acid, 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 can include at least a portion of an automotive part. This document also provides automotive parts at least partially coated with at least a portion of a coating system and / or film according to this disclosure.

[0063] "Radar transmission substrate" refers to a substrate whose composition and thickness are suitable for transmitting electromagnetic radiation with minimal transmission loss (if any) at various radar frequencies (e.g., in the automotive frequency range of 76 GHz to 81 GHz). For example, a radar transmission substrate can be transparent to various radar frequencies. That is, the OWRTL of a radar transmission substrate can be no greater than 5 dB, as measured by the radar tests described below. Radar transmission substrates can be non-metallic and include polymeric substrates such as plastics, including polyesters, polyolefins, polyamides, cellulose, polystyrene, polyethylene terephthalate, polyacrylic acid, polyethylene naphthalate, polypropylene, polyethylene, nylon, ethylene-vinyl alcohol, polylactic acid, other "green" polymeric substrates, polyethylene terephthalate, polycarbonate, polycarbonate-propylene-butadiene-styrene, polyurethane, thermoplastic olefins, polyamides, or combinations thereof. Radar transmission substrates can be filled or unfilled plastics. Filled plastics include plastics with additives such as fibers, glass fibers, and / or granules such as talc. Radar-transmitting substrates may include glass, wood, or combinations thereof.

[0064] For example, a coating stack applied to a radar-transmitting substrate in automotive repair or aerospace applications may include optional pretreatment and / or tackifier layers, a primer layer, a base coat, and a clear coat. Similarly, a coating stack applied to a radar-transmitting substrate in automotive repair, general industrial, or aerospace applications may include optional pretreatment or tackifier layers, a primer layer, and a direct gloss topcoat. A direct gloss topcoat refers to a coating that includes both color (e.g., flake pigment) and gloss in a single coating layer; this coating is typically the last coating in the coating stack. An additional clear coat may be applied over the direct gloss coating.

[0065] The coating system and / or film according to this disclosure can also be suitably incorporated into articles of manufacture, for example, articles formed by injection molding or additive manufacturing processes (e.g., 3D printing). In this way, the coating system and / or film can be applied to automotive parts, aerospace parts, consumer electronics parts, etc. Such parts are expected to have a "glittery" or metallic appearance while also being advantageous for radar transmission. For example, automotive parts may include bumper panels, mirror housings, fenders, hoods, trunks, doors, etc. Aerospace parts may include nose cones and radomes.

[0066] In-mold coating (IMC) is an alternative to painting injection-molded plastic parts. IMC can be performed by injecting a first coating composition and a second coating composition according to the present disclosure onto the surface of the article while it is still in the mold. Each coating composition then cures and adheres to the article. The coating system or film according to the present disclosure can be applied to the mold prior to the injection molding of the article, such that the coating or film is applied to the surface of the molded article. Both methods are IMC according to the present disclosure.

[0067] When applied to a substrate to form a coating or as a film, the coating compositions and films according to this disclosure can result in the substrate having favorable radar transmission properties and desired aesthetics.

[0068] When a radar system is placed near and / or adjacent to the coating system and / or film of this disclosure and / or an article incorporating the coating system and / or film, the radar system can emit electromagnetic waves that can efficiently and effectively pass through the coating system, film, and / or article. With the coating system, film, and / or article provided by this disclosure, even if there is radar transmission loss, it is minimal. The resistivity of prior art coating systems with fully incorporated conductive metallic effect pigments is significantly lower than that of the flake pigments of this disclosure, resulting in high radar transmission loss. Because the coating system according to this disclosure includes a large amount of radar-transmitting pigment, the coating system can effectively transmit electromagnetic radiation, including radar frequency wavelengths, so that the electromagnetic radiation can leave the coating system with minimal electromagnetic wave transmission loss (if any). The electromagnetic radiation leaving the coating, film, and / or article can be used to detect objects. For example, the electromagnetic radiation may be reflected back from the object, pass through the coating system, film, and / or article, and be detected by the radar system.

[0069] A method is provided to improve radio detection and ranging in the electromagnetic radiation frequency range of 1 GHz to 300 GHz (e.g., 1 GHz to 100 GHz or 76 GHz to 81 GHz) by utilizing a radar sensor mounted behind an article coated with a metallic effect, compared to a substrate coated with a coating system including aluminum flakes. The method includes applying a coating system according to this disclosure onto a substrate, such as an automotive substrate.

[0070] As used herein, unless otherwise expressly stated, all figures, such as those representing values, ranges, quantities, or percentages, may be interpreted as beginning with the word "about," even if the term is not explicitly stated. Any numerical ranges listed herein are intended to include all subranges contained therein. Plurals encompass singulars, and vice versa. For example, while the invention is described according to "a" pigment, "a" substrate, "a composite layer," "a radar-transmitting pigment," "a primer layer," "a base coat," etc., more than one of these and other components, including mixtures, may be used.

[0071] Furthermore, as used herein, the term "polymer" means both prepolymers, oligomers, and homopolymers and copolymers; the prefix "poly" means two or more. When ranges are given, any endpoints of those ranges and / or numbers within those ranges may be combined with the ranges of the invention. The terms "comprising," "such as," "for example," and similar terms mean "comprising / such as / for example but not limited to." The terms "acrylic acid" and "acrylate" are used interchangeably (unless doing so would change the intended meaning) and include acrylic acid, acid anhydrides and their derivatives, lower alkyl-substituted acrylic acid, such as C1-C2 substituted acrylic acid, such as methacrylic acid, ethylacrylic acid, etc., and their C1-C6 alkyl esters and hydroxyalkyl esters, unless otherwise expressly stated.

[0072] As used herein, the terms “on,” “applied to,” “formed on,” “deposited on,” “covered,” and “provided on” mean formed, covered, deposited, or provided on a surface, but not necessarily in contact with the surface. For example, a coating “formed on” a substrate does not exclude the presence of one or more other coatings of the same or different composition located between the formed coating and the substrate.

[0073] 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 on a substrate. Therefore, the terms "cure" and "curing" do not solely encompass the physical drying of the coating composition by solvent or carrier evaporation. In this respect, the term "curing" as used in this specification refers to the state of the coating, i.e., the components of the coating composition forming the layer have undergone a chemical reaction, forming new covalent bonds in the coating (e.g., forming new covalent bonds between the adhesive resin and the curing agent).

[0074] As used in this specification, the term "formation" means the production of an object from a composition by a suitable process (such as curing). For example, a coating formed from a curable coating composition means a single or multiple layer of coating or coated article produced by curing the coating composition under suitable process conditions.

[0075] Example

[0076] This disclosure will be more fully understood by referring to the following examples, which provide illustrative and non-limiting aspects of this disclosure. It should be understood that this disclosure is not necessarily limited to the examples described in this section.

[0077] As used herein, the term “part” refers to parts by weight unless otherwise stated.

[0078] Although the wide range of numerical values ​​and parameters described in this invention are approximations, the values ​​presented in specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement results.

[0079] Although specific examples of this disclosure have been described above for illustrative purposes, it will be apparent to those skilled in the art that various changes may be made to the details of this disclosure without departing from the disclosure as defined in the appended claims.

[0080] Use the BYKmac I multi-angle spectrophotometer to measure multi-angle color data according to the manufacturer's instructions, including measuring L at different angles using a D65 light source and a 10° observer. Value. The L value reported in the instance. The value is the average of three measurements.

[0081] To prepare an effect pigment formulation for use as a base coat, combine DBC500 with the desired pigments listed in Table 1 below. Combine the DBC500 and pigments and stir by hand for approximately 3 minutes, then add DT885 and shake for approximately 2 minutes.

[0082] Table 1. Effect pigment mixtures for the second layer

[0083]

[0084] a – DELTRON colorants, including cellulose acetate butyrate and polyacrylate, are available from PPG Industries, Inc.

[0085] b – Aluminum pigment paste, available from Toyal

[0086] c - Non-conductive mica pigments are available from BASF Colors & Effects.

[0087] d - Non-conductive mica pigments are available from Merck KGaA in Darmstadt, Germany.

[0088] e – DELTRON heat desiccant is available from PPG Industries, Inc.

[0089] Prepare the coating composition according to formulation AC in Table 1 and spray it onto a TPO substrate (Lyondell Basell HiFax TRC779X, 4×12×0.118 inches, available from Standard Plaque Inc., Melvindale, MI), in one or more layers, with a DFT of 0.5 mils to 2.0 mils (12 microns to 50 microns), thereby forming a second layer (e.g., a gray first layer or a black first layer) on top of the first layer. Additionally, when measuring opacity, spray the coating composition onto a 3×5×3 / 16-inch black / white Metopac T12G board from Leneta Company as needed. Before spraying the TPO board with the coating composition prepared according to formulation AC in Table 1, clean the TPO board with an SU4901 cleaning and scrubbing pad, wipe it with an SU4902 plastic adhesive wiping cloth, and spray with SUA4903 advanced plastic adhesive (all available from PPG Industries, Inc.). The DAS3025 gray acrylic polyurethane sealant was then combined with DCX3030 primer hardener and DT885 warm 75–90℉ (24–32) de-icing agent (both available from PPG Industries, Inc.) and applied to a target DFT of 0.8 mil to 1.0 mil (20 microns to 25 microns) using a SATAjet BF100 spray gun with a 1.3 mm nozzle and a gun pressure of 28 psi (1.9 bar). The DAS3025 sealant was allowed to dry / cur under ambient conditions for 15 to 60 minutes before applying the next coat. In the case of a gray undercoat (e.g., the first coat), the coating composition according to formulation AC in Table 1 was applied over the DAS3025. Where a black undercoat (e.g., a first coat) is required, combine DBC9700 DELTRON black undercoat (available from PPG Industries, Inc.) with DT885 at a 2:1 volume ratio and spray two coats over DAS3025 sealant using a SATAjet 1500 B High Flow Low Pressure (HVLP) SoLV with a 1.3 mm nozzle and a gun pressure of 28 psi (1.9 bar). After application, allow the DBC9700 layer to flash for 15 minutes (e.g., maintain at ambient temperature and allow some volatile contents of the coating to evaporate) before applying the effect pigment formulation.If a dark gray layer is required (e.g., a first coat), combine a 71w% DMD1683 / 29w% DMD1684 mixture (DELTRON primer available from PPG Industries, Inc.) with DT885 at a 1:1 volume ratio of DMD mixture to DT885, and spray two coats onto DAS3025 sealant using a SATAjet 1500 B HVLP SoLV with a 1.3 mm nozzle and a gun pressure of 28 psi (1.9 bar). After application, allow the DMD mixture layer to flash for 15 minutes before applying the effect pigment formulation.

[0090] Before spraying, stir the formulation AC in Table 1 by agitation, and spray the paint onto previously applied gray (DAS3025 is the previously applied paint), dark gray (DMD1683 / DMD1684 mixture is the previously applied paint), and black (DBC9700 is the previously applied paint) boards using a SATAjet 1500 B HVLP SoLV with a 1.3 mm nozzle and a gun pressure of 28 psi (1.9 bar). Perform flash drying for 5 to 10 minutes between coats, and determine if the coating is dry when it is no longer tacky (e.g., the coating surface is no longer sticky) (typically treated at 20°C for 15 to 20 minutes). The black / white Metopac boards are also coated with the effect pigment formulation in Table 1 in the same manner by spraying the formulation directly onto them.

[0091] Finally, a clear protective coating was applied to the TPO and black / white Metopac boards. PPG DELTRON solvent-based clear coat (Velocity Premium Clearcoat; DC 4000) was prepared by mixing DC 4000 with a hardener (DCH 3085) at a volume ratio of 4:1. The mixture was stirred before spraying. Two layers of clear coat were applied to the effect pigment formulations in Table 1 on both substrates using an HVLP gravity feed spray gun (Iwata WS400) with a 1.3 mm nozzle and a gun pressure of 28 psi (1.9 bar). The clear coat was applied by flashing the two coats at ambient temperature for 5 to 10 minutes between coats. The clear coat was cured as described in the publicly available technical data sheets, for example, in a convection oven at 60°C for 20 minutes or at 21°C for 4 to 6 hours. All DFTs were measured by spraying a 0.020x2x12 inch steel film inspection board (available from Q-Lab Corporation, Westlake, Ohio, order number SP-105293) while spraying other boards and measuring the cured coating thickness on the film inspection board using an FMP40C Dualscope (available from Fischer Technology, Inc.).

[0092] Effect pigment mixture applied to black / white Metopac boards

[0093] Formulas B and C were applied to black / white Metopac boards and then surface-coated with DC 4000 clear varnish as described above. Table 2 summarizes the observation data.

[0094] Table 2. Observations when formulations B and C were applied to black / white Metopac plates.

[0095]

[0096] 1 –The black or white portion of the T12G model 3 x 5 x 3 / 16 inch black / white Metopac board is available from Leneta Company.

[0097] 2 –Measured according to contrast test

[0098] When measured on a white substrate (Comparative Example 1), the anisochromaticity of formulation B is only 8.8, but when measured on a black substrate (Invention Example 2), the anisochromaticity is 19.4. When measured on a white substrate (Comparative Example 3), the anisochromaticity of formulation C is only 9.8, but when measured on a black substrate (Invention Example 4), the anisochromaticity is 20.5. It can be seen that a dark substrate plus a second layer with a contrast ratio less than 0.98 helps to obtain the desired anisochromaticity measurement value of ≥19.

[0099] Effect pigment mixture applied on a gray or black base

[0100] As described above, the formulation AC was sprayed onto a gray, dark gray, and / or black substrate. Table 3 below summarizes the observation data.

[0101] Table 3. Observations on formulation AC applied to TPO and black / white Metopac boards.

[0102]

[0103] 1 –Gray: DAS3025 sealant is a layer with effect pigment formulation applied on top; Black: DBC9700 black base coat is a layer with effect pigment formulation applied on top;

[0104] Dark gray: 71w% DMD1683 / 29w% DMD1684 base coat mixture is a layer on which an effect pigment formulation is applied;

[0105] 2 –Measured according to contrast test

[0106] Comparative Examples 5 and 6 use formulation A containing aluminum flake pigment. This pigment is conductive, significantly reducing the radar transmittance of the coating, but it provides a reasonable L... 15 Compared to the angle-dependent colorimetric index, for example, the radar transmittance percentages of Comparative Examples 5 and 6 are 60.2% and 61.0%, respectively, which is undesirable for radar applications. Note that because Comparative Examples 5 and 6 have a contrast ratio of 1.0, regardless of the underlying L... Regardless of the SCE value, the observed angle-dependent colorimetric index is similar.

[0107] Comparative Examples 7 and 8, as well as Invention Example 9, used compound B, differing only in the base color. When the base color changed from gray to dark gray and then black, the observed angle-dependent heterochromaticity index increased from 12.1 to 18.2 and 19.5, respectively. Furthermore, it can be seen that the radar transmittance % of Comparative Examples 7 and 8 is similar to that of Invention Example 9, both exceeding 80%.

[0108] Comparative Examples 10 and 11, as well as Invention Example 12, used compound C, differing only in the base color. When the base color changed from gray to dark gray and then black, the observed angle-dependent heterochromaticity index increased from 12.1 to 17.4 and 19.5, respectively. Furthermore, it can be seen that Comparative Examples 10 and 11 have similar radar transmittance percentages to Invention Example 12, both exceeding 80%.

[0109] The above examples demonstrate that using L A coating system with a dark first layer of SCE not greater than 10 and a subsequent second layer of flake pigment (where the contrast of the second layer is not greater than 0.80) can achieve an angle-dependent color index of 19 or greater and a radar transmittance percentage of 80% or greater.

[0110] As used herein, the term “average” means the “average” of any variable x (e.g., wavelength, diameter, lateral dimension, thickness, etc.) calculated by the following equation: average = (1 / N)Σxi, where N values ​​of variable x are averaged such that i = 1 to N, and Σxi = x1+x2+…+xN, as described in Philip R. Bevington and D. Keith Robinson, “Data Reduction and Error Analysis for the Physical Sciences” (2nd ed., 1992, pp. 8-9, ISBN 0-07-911243-9).

[0111] Various features and characteristics are described in this specification to provide an understanding of the composition, structure, production, function, and / or operation of this disclosure, including the disclosed compositions, coatings, and methods. It should be understood that the various features and characteristics of this disclosure can be combined in any suitable manner, regardless of whether such features and characteristics are explicitly described in combination in this specification. The inventors and the applicant expressly desire that combinations of such features and characteristics be included within the scope of this disclosure. Therefore, the claims may be amended to recite 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 expressly deny 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 new content to the specification or claims and will comply with the requirements of written description, sufficient description, and addition.

[0112] Unless otherwise specified, 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. Therefore, and to the extent necessary, the express disclosures set forth in this specification supersede any conflicting material incorporated by reference. Any material or portion 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 the incorporated material does not conflict with any existing disclosures. The applicant reserves the right to amend this specification to expressly reference any subject matter or portion thereof incorporated by reference. Amendments to this specification to include such incorporated subject matter will comply with the requirements of written description, adequate description, and added content.

[0113] While this disclosure provides descriptions of various specific aspects to illustrate its various aspects and / or its potential applications, it should be understood that various changes and modifications will occur to those skilled in the art. Therefore, this disclosure should be understood to be at least as broad as the claims, and not limited to the specific illustrative aspects provided herein.

Claims

1. A coating system comprising: The first layer includes First film-forming resin; and First pigment, The measurements were taken using an integrating sphere spectrophotometer with a D65 light source, a 10° observer, and under conditions of excluding specular reflection components. The first layer of CIELAB L... The value is no greater than 10; as well as A second layer disposed on at least a portion of the first layer, the second layer comprising: Second film-forming resin; and Flake pigments, The contrast ratio of the second layer was measured using an integrating sphere spectrophotometer under conditions of a D65 light source, a 10° observer, and including specular reflection components, according to contrast testing. The coating system has an angle-dependent colorimetric index of 19 or greater, as measured using a multi-angle spectrophotometer with a D65 light source and a 10° observer, according to the following equation: Different color index with angle = 2.69 (L) 15 -L 110 ) 1.11 / (L 45 ) 0.86 in: L 15 CIE L was measured at a non-mirror angle of 15°. value; L 45 CIE L was measured at a non-mirror angle of 45°. Value; and L 110 CIE L was measured at a non-mirror angle of 110°. value.

2. The coating system of claim 1, wherein the second layer comprises 2% by weight or less aluminum flakes based on the total weight of the second layer.

3. The coating system according to claim 1, wherein the flake pigment comprises mica pigment, oxide-coated mica pigment, glass flake, oxide-coated glass flake, visible light diffraction pigment, visible light reflective organic pigment, metal oxide flake, radar transmission composite pigment, or a combination thereof.

4. The coating system according to claim 1, wherein the first pigment comprises carbon black, iron oxide, perylene black, pigment blue 15:1, pigment blue 15:3, pigment brown 25, pigment red 101, pigment red 179, pigment red 202, pigment red 257, pigment red 264, pigment violet 19, pigment violet 29, pigment yellow 129, pigment yellow 139, pigment 150, pigment yellow 42, or a combination thereof.

5. The coating system of claim 1, wherein the first pigment comprises a nano-sized pigment with an average primary particle size of less than 100 nm.

6. The coating system of claim 1, wherein the first pigment, as measured according to ASTM D1003, comprises a haze of no more than 5%.

7. The coating system of claim 1, wherein the coating system transmits 80% or more of electromagnetic radiation with a frequency of 1 GHz to 300 GHz through the coating system.

8. The coating system of claim 7, wherein the first layer, the second layer, or a combination thereof comprises a dry film thickness of 5 μm to 100 μm.

9. The coating system of claim 1, wherein the L of the coating system 15 115 or greater.

10. The coating system of claim 1, wherein the first layer has a blackness of 350 or greater, measured using a multi-angle spectrophotometer at 110° with a D65 light source and a 10° observer.

11. The coating system of claim 1, wherein the first layer, the second layer, or the combination thereof further comprises additional pigments, plasticizers, flow control agents, thixotropic agents, rheology modifiers, catalysts, antioxidants, antimicrobial agents, defoamers, surfactants, dispersants, thickeners, stabilizers, fillers, organic cosolvents, water, reactive diluents, abrasive carriers, or combinations thereof.

12. The coating system of claim 1, wherein the first layer, the second layer, or the combination thereof further comprises abrasion-resistant particles, film-reinforcing particles, cellulose acetate butyrate, wetting agents, clay, ultraviolet absorbers, and / or stabilizers, or combinations thereof.

13. The coating system of claim 1, wherein the first layer, the second layer, or a combination thereof further comprises a histamine light stabilizer.

14. The coating system of claim 1, further comprising a base coat, an intermediate coat, a top coat, a primer layer, or a combination thereof.

15. The coating system of claim 1, further comprising a pretreatment layer, a tackifier layer, or a combination thereof.

16. The coating system of claim 1, wherein the first layer is a primer layer and the second layer is a base coat layer.

17. A coating system comprising, and / or a film formed therefrom, according to claim 1.

18. An article comprising a coating system according to claim 1 or a film according to claim 17 deposited on a substrate.

19. The article of claim 18, wherein the substrate comprises an industrial substrate.

20. The article of claim 18, wherein the substrate comprises building substrate, automotive substrate, marine substrate, aerospace substrate, consumer electronics substrate, or a combination thereof.

21. The article of claim 18, wherein the substrate comprises a roll substrate.

22. The article of claim 18, wherein the substrate comprises a packaging substrate.

23. The article of claim 18, wherein the substrate comprises a bumper panel, a mirror housing, a fender, a hood, a trunk, a door, or a combination thereof.

24. The article of claim 18, wherein the substrate is radar-transmissive.

25. An automotive component coated with at least a portion of the coating system according to claim 1 or the film according to claim 17.

26. A method for improving radio detection and ranging in the electromagnetic radiation frequency range of 1 GHz to 300 GHz using a radar sensor mounted behind an article coated with a metallic effect, the method comprising: Apply the coating system according to claim 1 and / or the film according to claim 17 to an automotive substrate.

27. The coating system of claim 7, wherein the coating system transmits 80% or more of electromagnetic radiation with a frequency of 76 GHz to 81 GHz through the coating system.

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