Coating system of multilayer structure and method for producing the same

Abstract

The present application provides a coating system with a multi-layer structure, which is coated with a reinforcing reflective primer layer, a toning primer layer, a color paint layer and a varnish layer in sequence from a substrate, the coating system can reflect light in the near-infrared spectrum region with a wavelength of 780nm-2500nm incident on the surface of the substrate, and can absorb light in the visible spectrum region with a wavelength of 380nm-780nm incident on the coated surface. The present application makes the coated surface present excellent black appearance. The surface with the coating system of the present application can absorb 380nm-780nm visible light to the maximum extent, and can reflect 780nm-2500nm near-infrared light to the maximum extent, so that it has better performance than other conventional coatings with black appearance and near-infrared reflection performance, and has stronger reflection performance for detection signals in the near-infrared band. The present application also provides a preparation method of the coating system, and a traffic facility or vehicle coated with the coating system. The coating system of the present application is particularly suitable for automatic driving scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology, in particular to a coating structure capable of reflecting near-infrared spectrum, more particularly to a coating system with multi-layer structure capable of reflecting near-infrared spectrum and a preparation method thereof. The coating system described in the present application is particularly suitable for the scenario of autonomous driving. BACKGROUND

[0002] Coating is a layer of material coated on the surface of an object with protective and decorative functions, and color is an extremely important attribute of coating. Different colors of coating and other color-related appearance elements will have different degrees of influence on the functionality and decoration of the coating.

[0003] With the iterative development of modern traffic technology elements, the influence of color on coating has gone beyond the scope of visual appearance, because the future functions of coating will include the influence on non-visible area optical performance such as machine vision and sensor perception, as well as microwave electromagnetic wave performance, and will become an important element of the comprehensive function of coating.

[0004] Intelligent transportation and autonomous driving are technologies that have developed rapidly in recent years. The latter is also known as the vanguard of AI (Artificial Intelligence) technology, representing the highest level of automation technology and the development trend of future transportation. Autonomous driving specifically refers to the automatic completion of cruising, lane changing, avoiding or overtaking, etc. by the effective cooperation of various sensors, computer analysis systems, decision systems and control systems. This way of requiring only a small amount of takeover or even full unmanned driving can better protect future traffic safety and greatly improve traffic efficiency by avoiding serious traffic accidents caused by human factors.

[0005] In the field of autonomous driving, laser radar sensors are one of the main sensing devices configured in current high-level autonomous driving cars, which have many advantages such as long-range identification, high resolution, and are not affected by environmental light. The sensor fusion scheme based on laser radar has become one of the mainstream approaches and is adopted by many automobile manufacturers.

[0006] Laser radar receives signals by emitting laser of specific wavelength from laser and reflecting on the surface of environmental objects. Based on the distance between the object and the signal source calculated by the time of the returned signal, laser radar can form a high-resolution data point cloud graph in three-dimensional space.

[0007] Current mainstream lidar uses near-infrared laser signals, and according to different technical routes, there are mainly two wavelengths of 905 nm and 1550 nm. Under the same equipment and environmental conditions, the signal intensity received by the lidar is directly related to the surface reflectivity of the measured environmental object, which will directly affect the detection distance and accuracy of the lidar, and then have a great influence on the safety redundancy of the entire autonomous driving system, and affect the configuration of algorithm and computing power, etc.

[0008] On the other hand, as one of the main properties of paint, color is also one of the most basic elements for ordinary consumers to choose products. For example, automobile manufacturers will regularly release popular color trends for cars, and black, white, silver gray, and precious red, precious blue, etc. will be favored by the public. The color of commercial vehicles or other public transportation tools will use simple and clear standard white, dark blue, green, black, and dark purple, each with its own characteristics, according to the city, purpose, year, region, etc.

[0009] In terms of surface reflectivity, for objects with surface coating, the surface reflectivity is basically determined by the characteristics and components of its coating, and different colors of the coating will greatly affect the reflectivity of the paint surface. Generally speaking, the lighter the color of the coating, the better the reflection of light, and the darker the color of the coating, the more obvious the absorption of light.

[0010] The laser light source used by sensors such as lidar is mostly in the near-infrared band, which is to avoid using visible light to avoid causing harm to the human eye. Under the premise of meeting the visual color performance, while giving the paint high reflectivity in the near-infrared region, it can help future sensors using near-infrared wave detection to produce higher responsiveness, so that tools with intelligent functions have more easily identifiable performance. This coating feature will help sensors break through their current limitations in maximum detection distance, detection angle, resolution and accuracy, broaden their application, reduce the probability of detection failure, and improve the safety of the system.

[0011] Therefore, the present application attempts to provide a coating multilayer structure, a coating composition, and a preparation method and system of a coating, which can maximize the reflection of near-infrared light spectrum incident on the coating surface from the outside while providing excellent black appearance. SUMMARY

[0012] In order to achieve the above-mentioned purpose of the application, the present application provides a coating system with a multilayer structure and a preparation method thereof. When the multilayer structure coating system is coated on the surface of an object, the light in the near-infrared region incident from the outside can be maximally reflected.

[0013] The coating system with multi-layer structure according to the present application can maximize the reflection of light in the near-infrared spectrum region with a wavelength of 780nm-2500nm incident on the coated surface, while maximizing the absorption of light in the visible spectrum region with a wavelength of 380nm-780nm incident on the coated surface. Accordingly, the coating system according to the present application is particularly suitable for use in the context of autonomous driving.

[0014] According to the first aspect of the present application, there is provided a coating system with multi-layer structure, wherein, from the coated substrate, it is successively coated with a reinforcing reflective primer layer, a toning primer layer, a color paint layer and a clear paint layer, wherein:

[0015] The clear paint layer is a transparent coating with high transmittance in the spectral region with a wavelength of 380nm-2500nm;

[0016] The color paint layer can both absorb visible light with a wavelength of 380nm-780nm and transmit light in the near-infrared spectrum region with a wavelength of 780nm-2500nm;

[0017] The toning primer layer can absorb visible light with a wavelength of 380nm-780nm entering the coating;

[0018] The reinforcing reflective primer layer can reflect light in the near-infrared spectrum region with a wavelength of 780nm-2500nm entering the coating; so that

[0019] The coating system with multi-layer structure can reflect light in the near-infrared spectrum region with a wavelength of 780nm-2500nm incident on the surface of the coated substrate, while being able to absorb light in the visible spectrum region with a wavelength of 380nm-780nm incident on the coated surface.

[0020] Clear coat layer

[0021] Further, the clear paint layer comprises a transparent coating of resin and additives, without pigments or fillers. It has high transmittance in the spectral region with a wavelength of 380nm-2500nm, and serves the purpose of protecting the color of the coating from fading and weathering.

[0022] In particular, as an embodiment of the present application, the clear paint can be exemplarily selected from the single-component baking clear paint MAC-O1860 or the two-component polyurethane high solid 2K clear paint provided by Axalta Coating Systems.

[0023] Color coat layer and non-hiding color coat

[0024] Further, the color paint layer comprises at least three non-hiding pigments having transmittance in the near-infrared spectral region of 780 nm to 2500 nm; the superimposed spectrum of the non-hiding pigments shows strong absorption in the spectral range of 380 nm to 780 nm and high transmittance in the spectral range of 780 nm to 2500 nm.

[0025] The non-hiding pigments having transmittance are selected by the following method:

[0026] In the spectral range of 380 nm to 2500 nm, a continuous and uniform film with a certain thickness is obtained by coating a dispersion liquid of the pigments on white and black card papers, and the reflectance values of the film in the spectral region of 380 nm to 2500 nm are scanned using an integrating sphere ultraviolet spectrophotometer in reflection mode.

[0027] The non-hiding pigments satisfy the following conditions simultaneously:

[0028] I. The reflectance measured on black base card paper in the spectral range of 380 nm to 2500 nm is less than 30%;

[0029] II. The reflectance measured on white base card paper in the spectral range of 780 nm to 2500 nm is greater than 35%.

[0030] Preferably, the non-hiding pigments satisfy the following conditions simultaneously:

[0031] I. The reflectance measured on black base card paper in the spectral range of 380 nm to 2500 nm is less than 10%;

[0032] II. The reflectance measured on white base card paper in the spectral range of 780 nm to 2500 nm is greater than 50%.

[0033] Further, the particle size of the non-hiding pigments is about 0.01 to 0.05 μm; preferably, the particle size is about 0.01 to 0.025 μm.

[0034] Further, the non-hiding pigments include a combination of at least three of indanthrone blue, copper (II) phthalocyanine-based blue pigments, YInMn indium manganese blue, perylene-based black pigments, perylene-based red pigments, non-hiding DPP red pigments, quinacridone-based red pigments, quinophthalone-based pigments, isoindolinone yellow yellow pigments, and benzimidazolone-based yellow orange pigments.

[0035] Preferably, the non-hiding pigments comprise a phthalocyanine copper blue pigment, a DPP transparent red pigment, and a transparent benzimidazolone or isoindolinone yellow yellow pigment.

[0036] In addition, it should be noted that cobalt blue, cobalt green pigments, carbon black pigments, iron oxide pigments, copper-chromium black pigments, cobalt black pigments, manganese oxide black, titanium black, etc. have strong absorption in part or all of the near-infrared spectral region 780nm-2500nm, which are not suitable for use as the near-infrared transmitting pigments described in the present application.

[0037] Further, the non-hiding paint used in the color paint layer comprises the following components by weight:

[0038]

[0039]

[0040] Further, the preparation method of the non-hiding paint comprises the following steps:

[0041] (a) Add deionized water, pH adjuster and part of the rheological aid to a premix container, stir and mix uniformly at a speed of 800-2000 rpm, then add amino resin A and amino resin B and stir to disperse uniformly, continue to add polyester resin, polyurethane resin and part of the defoaming agent to the above mixture, then add acrylic resin A and acrylic resin B and continue to stir;

[0042] (b) In another premix container, add solvent, modified acrylic resin and leveling agent, and mix and stir to disperse uniformly at a speed of 800-2000 rpm, then add the mixed material to the mixture obtained in step (a) and continue to stir;

[0043] (c) Add the non-hiding pigment color powder, the remaining rheological aid, defoaming agent, transparent filler and pH adjuster in sequence, continue to stir at a speed of at least 1500 rpm, and add deionized water to the appropriate viscosity (35-60 KU) to obtain the non-hiding paint.

[0044] Accordingly, the color paint layer can absorb visible light with a wavelength of 380-780 nm to a great extent by adding a series of the color filler composition, while transmitting light in the near-infrared spectrum region with a wavelength of 780-2500 nm. Further, the color paint layer should make the visible light with a wavelength of 380-780 nm have smaller reflection. The pigment particles with a particle size of >0.05 μm are not conducive to the full absorption of the visible spectrum because they will produce more scattering of light. The use of pigments with a particle size of about 0.01-0.025 μm can reduce the scattering of the visible spectrum, while a larger specific surface area of the pigments is conducive to the absorption of the visible spectrum, so that the multilayer coating can have a better black appearance.

[0045] Tint base coat layer

[0046] Further, the toning primer layer comprises at least one dark cool color pigment having transmittance in the near-infrared spectrum region with a wavelength of 780-2500 nm, and

[0047] at least one pigment having reflectivity in the near-infrared spectrum region with a wavelength of 780-2500 nm.

[0048] The dark cool color pigment having transmittance includes indanthrone blue, copper (II) phthalocyanine, YInMn indium manganese blue, perylene black, and the like pigments having black or blue-violet color.

[0049] The pigment having reflectivity in the near-infrared spectrum region is selected by the following method:

[0050] In the spectrum range of 780-2500 nm, a continuous and uniform film with a certain thickness is obtained by coating a dispersion liquid of the pigment on white and black card papers, and the reflectivity value of the film in the spectrum region of 780-2500 nm is scanned by using an integrating sphere ultraviolet spectrophotometer in reflection mode.

[0051] The pigment having reflectivity in the near-infrared spectrum region satisfies the following conditions:

[0052] The reflectivity measured on the black base card paper in the spectrum region of 780-2500 nm is >30%. Preferably, the reflectivity measured on the black base card paper in the spectrum region of 780-2500 nm is >45%.

[0053] Further, the near-infrared spectrum region having reflective pigments include titanium white pigments, barium white pigments, zinc barium white pigments, zinc oxide, lithopone, bismuth oxide pigments, zirconium oxide pigments, covering DPP red, titanium yellow (nickel titanate yellow) pigments, bismuth vanadate yellow, benzimidazolone-based pigments, yttrium indium oxide blue pigments (YIn x Oy), CICP (Complex Inorganic Color Pigment) inorganic composite pigments such as iron manganese titanium black, and the like.

[0054] Further, the near-infrared spectrum region having reflective pigments include white pigments having high reflectivity. This refers to special titanium white pigments having a reflectivity > 45% in the near-infrared spectrum region 780 nm to 2500 nm according to the reflectivity test method described above. The special titanium white pigments are special titanium white pigments having higher near-infrared reflectivity than conventional titanium white pigments.

[0055] Specifically, as an embodiment of the present application, the special titanium white pigments can be exemplarily selected from the W400, W550, W800 series of infrared reflective titanium white pigments or similar white pigments provided by the company Pantone.

[0056] Preferably, the toning primer layer includes a combination of at least one or several of conventional titanium white pigments and special titanium white pigments having higher near-infrared reflectivity.

[0057] In addition, it should be noted that cobalt blue, cobalt green pigments, carbon black pigments, iron oxide pigments, copper chromium black pigments, cobalt black pigments, manganese oxide black, and the like, which are strongly absorbing pigments in part or all of the wavelength range in the near-infrared spectrum region 780 nm to 2500 nm, are not suitable for use as the toning primer layer coloring pigments of the present application. CICP inorganic composite dark pigments such as iron manganese titanium black are particularly unsuitable for use as the toning primer layer coloring pigments of the present application.

[0058] Further, the toning primer used in the toning primer layer comprises, by weight fraction:

[0059] Saturated polyester 5-8 parts Modified acrylic resin 15-25 parts Water-based polyester resin 15-25 parts Etherified melamine resin 2-5 parts Amino resin 4-7 parts Water-based polyurethane resin 5-10 parts Blocked isocyanate 1-2 parts Pigment 1-30 parts Transparent filler 10-30 parts pH adjuster 1-4 parts Auxiliary agent 4-6 parts Solvent 5-9 parts Deionized water 10-27 parts

[0060] Further, the preparation method of the toning primer includes the following steps:

[0061] (a) sanding:

[0062] I) Mix saturated polyester, solvent, pH regulator, and under stirring condition, add part of deionized water, wetting agent, first dispersant, cosolvent, etherified melamine resin, continue stirring, then add pigments and transparent fillers, control reaction temperature < 35℃;

[0063] II) Add part of defoaming agent, stir and adjust pH to 8.5±0.4, add deionized water to adjust viscosity to 100±5 ku, transfer the obtained mixture to a sand mill, stir at 600-800 rpm for 15 minutes, increase the speed to 800-1200 rpm for 10 minutes;

[0064] III) Grind to fineness < 15 μm;

[0065] (b) Thinning:

[0066] Add the mixture obtained in step (a) above into a mixing vessel, stir, and slowly add modified acrylic resin, water-based polyester resin, deionized water, amino resin, blocked isocyanate, water-based polyurethane resin, and the remaining defoaming agent and second dispersant, and disperse uniformly at a speed of 800-1200 rpm; finally, adjust to 8.5±0.4 with pH regulator, to obtain the toning primer.

[0067] The toning primer layer can further absorb the visible light with wavelength of 380-780 nm entering the coating by adding infrared transmission type dark cool color pigments, further reduce the visible light with wavelength of 380-780 nm reflected by the coating; meanwhile, the infrared reflection type pigments contained in the toning primer layer can greatly reflect the near infrared light with wavelength of 780-2500 nm entering the coating. Accordingly, the toning primer layer can make the multilayer coating obtain lower visible light reflection and higher near infrared light reflection effect, and exhibit better black appearance and near infrared reflection performance.

[0068] Enhanced reflective base coat layer

[0069] Further, the enhanced reflection primer layer comprises at least one of metal flaky pigments with strong reflectivity in the near infrared spectrum region or white pigments with strong reflection performance.

[0070] The metal flaky pigments with strong reflectivity in the near infrared spectrum region are selected by the following method:

[0071] In the spectrum range of 780-2500 nm, a continuous and uniform film with certain thickness is obtained by coating the dispersion liquid of the pigments on white and black card papers, and the reflectivity values of the film in the spectrum range of 780-2500 nm are measured by scanning the film in the reflectance mode using an integrating sphere ultraviolet spectrophotometer.

[0072] The metal flaky pigment having strong reflectivity in the near infrared spectrum region satisfies the following conditions:

[0073] The reflectivity of the metal flaky pigment on black base card paper in the range of 780nm to 2500nm is >50% as tested by the reflectivity testing method described above.

[0074] Preferably, the reflectivity of the metal flaky pigment on black base card paper in the range of 780nm to 2500nm is >65%.

[0075] Specifically, the metal flaky pigment having strong reflectivity includes one or more of the following: electroplated aluminum silver paste, imitation electroplated silver aluminum silver paste, silver-coated glass flakes or mica flakes.

[0076] The electroplated aluminum silver paste is a non-floating type electroplated aluminum silver paste or a floating type electroplated aluminum silver paste. For example, it is selected from the L-55700 electroplated aluminum silver paste provided by the Aikai Company.

[0077] The silver-coated glass flakes or mica flakes are, for example, selected from special pigments such as the StarLight series of sparkling effect pigments provided by the Xuetian Company.

[0078] Accordingly, the enhanced reflective primer layer can maximize the reflection of light in the near infrared spectrum region with a wavelength of 780nm to 2500nm entering the coating, while minimizing the impact of the substrate on the near infrared light reflection performance of the coating.

[0079] According to the second aspect of the present application, a method for preparing the coating system having a multi-layer structure as described above is provided, which comprises the following steps:

[0080] (1) applying an enhanced reflective primer on the surface of the substrate;

[0081] (2) applying a toning primer on the coating obtained in step (1);

[0082] (3) applying a colored paint on the coating obtained in step (2);

[0083] (4) applying a clear paint on the coating obtained in step (3) and performing baking or normal temperature drying, thereby obtaining a coating system having a multi-layer structure.

[0084] Further, the coating method includes spraying, rolling, showering, and spin coating, etc.

[0085] Further, the time and temperature of the baking used varies according to different coating base resins, including low-temperature baking (60-80°C) or high-temperature baking (100-140°C). In addition, for some high-activity resin systems, drying at room temperature can also be used (for example, amino-cured epoxy resin or polyurea-cured systems, etc.).

[0086] According to a third aspect of the present application, the multi-layer structure and coating composition can be used for surface coating of various objects and various coating processes.

[0087] In particular, the third aspect of the present application provides a traffic facility or vehicle, wherein the surface of the traffic facility or vehicle is coated with the coating system of the first aspect of the present application.

[0088] Further, the use scenarios of the multi-layer coating include but are not limited to:

[0089] (1) The object to be coated can be sensed and more easily sensed by a sensor;

[0090] (2) The object to be coated can reflect a portion of the sunlight;

[0091] (3) The sensor can be a mechanical or solid-state laser radar using a 905 nm or 1550 nm laser light source;

[0092] (4) The sunlight reflectivity can be represented by the TSR% value of the coating surface.

[0093] Advantages of the present invention are as follows:

[0094] Compared with the prior art, the present application achieves excellent black appearance of the coated surface by special design of the multi-layer coating structure and selection of suitable pigments. The surface with the coating system of the present application can absorb visible light of 380 nm-780 nm to the maximum extent and reflect near-infrared light of 780 nm-2500 nm to the maximum extent at the same time, so as to have better performance than conventional coatings with black appearance and near-infrared reflection performance, and stronger reflection performance for detection signals using near-infrared waveband as signal source (such as light signals emitted by sensors such as laser radar).

[0095] In addition, the coating system of the present application also has excellent mechanical properties, durability, aging resistance and corrosion resistance, and has good appearance effect.

[0096] Therefore, in many scenarios matched with the automatic driving vehicle road cooperation system, it can be used as the surface coating of various facilities to provide decoration and protection. BRIEF DESCRIPTION OF DRAWINGS

[0097] Figure 1 The schematic diagram of the coating system of the present application is shown; wherein 1 is the substrate, 2 is the enhanced reflective primer layer, 3 is the toning primer layer, 4 is the color paint layer, and 5 is the clear paint layer.

[0098] Figure 2 The structural schematic diagram of the substrate sample and its support for testing is shown; wherein 6 is the substrate sample, and 7 is the sample support.

[0099] Figure 3 The schematic diagram of the laser radar signal reflection intensity testing method is shown; wherein 8 is the laser radar, and 9 is the laser radar support. The angle between the incident signal and the sample can be adjusted by controlling the rotation angle of the sample support to achieve the purpose of changing the incident angle.

[0100] Figure 4 The schematic diagram of the appearance effect of the surface coated with the coating system of the present application is shown

[0101] Figure 5 The reflection spectrum diagram of the surface coated with the coating system of the present application is shown. DETAILED DESCRIPTION

[0102] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods in the following examples, if not specified, are usually carried out under the conventional conditions, or under the conditions recommended by the manufacturers. Unless otherwise specified, the percentages and parts are weight percentages and weight parts. The experimental materials and reagents used in the following examples, if not specifically mentioned, can be obtained from the market.

[0103] The raw materials and amounts are as follows:

[0104] The enhanced primer used in the enhanced reflective primer layer: sp5000 electroplated silver primer provided by Axalta Coating Systems;

[0105] The non-hiding color paint used in the color paint layer: prepared according to the following examples;

[0106] The toning primer used in the toning primer layer: prepared according to the following examples;

[0107] The clear paint used in the clear paint layer: MAC-O 1860 automotive clear paint provided by Axalta Coating Systems; original factory paint black: AR3500 water-based automotive topcoat (pearl black) provided by Axalta Coating Systems; original factory paint gray: AR600 water-based automotive primer (gray) provided by Axalta Coating Systems.

[0108] The experimental board is an electrophoresis board, a custom board, which has been coated with a conventional electrophoresis coating, and the appearance is light gray.

[0109] Preparation of non-hiding color coat used in the example color coat layer The raw materials and amounts of the non-hiding color coat are as follows:

[0110]

[0111]

[0112] The preparation method of the non-occluding color paint comprises the following steps:

[0113] (a) adding part of deionized water 16 parts, 0.8 parts of pH regulator and part of rheological aid 0.3 parts into a premixing container, stirring and mixing uniformly at a speed of 800-2000 rpm, then adding amino resin A and amino resin B to stir and disperse uniformly, continuing to add polyester resin, polyurethane resin and part of defoaming agent 0.2 parts into the above mixture, then adding acrylic resin A and acrylic resin B and continuing to stir;

[0114] (b) adding solvent, modified acrylic resin and leveling agent into another premixing container, mixing and stirring to disperse uniformly at a speed of 800-2000 rpm, then adding the mixed material into the mixture obtained in step (a) and continuing to stir;

[0115] (c) adding yellow, red and blue pigments in the pigments (transmissive non-occluding pigments) and optional pearl effect pigments (example 5 contains pearl effect pigments) in sequence, the remaining rheological aid 0.35 parts, dispersant 1, dispersant 2, defoaming agent 0.2 parts, transparent filler and 0.4 parts of pH regulator, continuing to stir at a speed of 1500 rpm, adding the remaining deionized water 9.9 parts to a suitable viscosity (35-60 KU), and obtaining the non-occluding color paint.

[0116] Preparation of tint base coat used in the example tint base coat layer

[0117] The raw materials and amounts of the toning primer are as follows:

[0118]

[0119]

[0120] The preparation method of the toning primer comprises the following steps:

[0121] (a) sanding:

[0122] I) mixing saturated polyester, solvent diethylene glycol butyl ether, 0.8 parts of pH regulator, and adding part of deionized water 10 parts, wetting agent, dispersant 1, cosolvent, etherified melamine resin under stirring condition, continuing to stir, then adding dark pigment, reflective pigment and transparent filler, controlling the reaction temperature < 35℃;

[0123] II) Add 0.5 parts of defoamer, stir and adjust the pH to 8.5±0.4, add 3.5 parts of deionized water, adjust the viscosity to 100±5ku, transfer the resulting mixture to a sand mill, stir at 600-800 rpm for 15 minutes, increase the speed to 800-1200 rpm and stir for 10 minutes.

[0124] III) Grind to a fineness of <15μm, using a water-based automotive-grade sand mill, with the sand milling process passed 4 times;

[0125] (b) Thinning: Add the mixture obtained in step (a) above to a mixing container and stir. Slowly add the modified acrylic resin, waterborne polyester resin, the remaining 6 parts of deionized water, amino resin, blocked isocyanate, waterborne polyurethane resin, the remaining 0.5 parts of defoamer and dispersant 2, and disperse evenly at a speed of 800-1200 rpm. Finally, adjust the pH to 8.5±0.4 with 0.6 parts of pH adjuster to obtain the tinted primer.

[0126] The base coat used for this color tinting is black.

[0127] Example 1 Coating system 1 with multi-layer structure

[0128] like Figure 1 As shown, the coating system described in this embodiment has four coating layers, which are arranged in the following order from the substrate 1: (1) Enhanced reflective primer layer 2; (2) Tinted primer layer 3; (3) Color paint layer 4; (4) Clear varnish layer 5.

[0129] in:

[0130] The enhanced reflective primer layer uses Nippon Paint's SP5000 electroplated silver primer, and the dry film thickness of the enhanced reflective primer layer is approximately 5 to 10 μm.

[0131] The tinted primer layer is the tinted primer prepared in the above embodiments, and the dry film thickness of the tinted primer layer is about 10-15 μm.

[0132] The paint layer is a non-masking paint prepared in the above embodiments, and the dry film thickness of the paint layer is about 8 to 13 μm.

[0133] The clear coat is MAC-O 1860 automotive clear coat provided by Nippon Paint, and the dry film thickness of the clear coat is approximately 25–35 μm.

[0134] In this embodiment 1, the tinting primer in the tinting primer layer uses a dark pigment DC1 ( Black L0086) and reflective pigment RC1 (W400 titanium dioxide).

[0135] In this embodiment 1, the non-hiding color paint in the color paint layer uses blue series near-infrared transmitting pigments, specifically pigments TC1 (P.B15:3, Blue L7085), pigment TC2 (P.R179, RedL3875) and pigment TC3 (P.Y.184, Yellow L1130).

[0136] The coating system and its sample plate of the present application are prepared by the following method:

[0137] Step (1): spray a layer of sp5000 electroplated silver primer provided by the company Riwba on the surface of the electrophoretic plate as the substrate, and bake at a temperature of 140°C for 20 min to form an enhanced reflective primer layer 2;

[0138] Step (2): spray a toning primer on the surface of the coating obtained in step (1), flash dry at 80°C for 15 min after leveling for 5 min to form a toning primer layer 3;

[0139] Step (3): spray a black non-hiding color paint on the surface of the coating obtained in step (2), flash dry at 80°C for 25 min after leveling for 5 min to form a color paint layer 4;

[0140] Step (4): spray a varnish on the surface of the coating obtained in step (2) to form a varnish layer 5;

[0141] Step (5): bake the multilayer coating system and the substrate obtained in step (4) at 140°C for 20-30 min to completely dry the entire coating system.

[0142] Place the obtained substrate sample plate with the coating system 1 of the present application in a dry and clean environment for subsequent color test, spectral test and laser radar reflection experiment test.

[0143] Example 2 Coating system 2 with multi-layer structure

[0144] In this embodiment 2, the coating structure of the coating system 2, and specifically the composition of the enhanced reflective primer layer 2 and the varnish layer 5 are consistent with those in embodiment 1.

[0145] Compared with embodiment 1:

[0146] (1) the toning primer in the toning primer layer uses dark pigments DC1 BlackL0086) and reflective pigments RC2 (W800 titanium white);

[0147] (2) The non-hiding color paint in the color paint layer uses near-infrared transmitting pigments, specifically pigments TC1 (P.B. 15:3, Blue L7085), pigments TC2 (P.R. 179, Red L3875), and pigments TC3 (P.Y. 184, Yellow L1130).

[0148] The preparation method of the coating system and the sample plate is also consistent with that of Example 1. The obtained sample plate with the coating system 5 of the present application is placed in a dry and clean environment for subsequent color test, spectral test, and laser radar reflection test.

[0149] Example 3 Coating system 3 with multi-layer structure

[0150] In this Example 3, the coating structure of the coating system 3, and specifically the composition of the enhanced reflective primer layer 2 and the varnish layer 5 are consistent with those in Example 1.

[0151] Compared with Example 1:

[0152] (1) The toning primer in the toning primer layer uses dark pigments DC2 Black L0095) and reflective pigments RC2 (W800 titanium white);

[0153] (2) The non-hiding color paint in the color paint layer uses near-infrared transmitting pigments, specifically pigments TC1 (P.B. 15:3, Blue L7085), pigments TC2 (P.R. 179, Red L3875), and pigments TC4 (P.Y. 138, Yellow L0962HD).

[0154] The preparation method of the coating system and the sample plate is also consistent with that of Example 1. The obtained sample plate with the coating system 5 of the present application is placed in a dry and clean environment for subsequent color test, spectral test, and laser radar reflection test.

[0155] Example 4 Coating system 4 with multi-layer structure

[0156] In this Example 3, the coating structure of the coating system 4, and specifically the composition of the enhanced reflective primer layer 2 and the varnish layer 5 are consistent with those in Example 1.

[0157] Compared with Example 1:

[0158] (1) The toning primer in the toning primer layer uses dark pigments DC1 Black L0086) and reflective pigment RC2 (W800 titanium white);

[0159] (2) The non-hiding color paint in the color paint layer uses infrared transmitting pigments, specifically pigments TC5 (P.B. 15:1, Blue L6930), pigment TC2 (P.R. 179, Red L3875) and pigment TC4 (P.Y. 138, Yellow L0962HD).

[0160] The preparation method of the coating system and its sample is also consistent with Example 1. The obtained substrate sample with the coating system 5 of the present application is placed in a dry and clean environment for subsequent color test, spectral test and laser radar reflection experiment test.

[0161] Example 5 Coating system 5 with multi-layer structure

[0162] In this embodiment 5, the coating structure of the coating system 5, and specifically the composition of the enhanced reflective primer layer 2 and the varnish layer 5 are consistent with those in Example 1.

[0163] Compared with Example 1:

[0164] (1) The toning primer in the toning primer layer also uses dark pigments DC1 Black L0086) and reflective pigment RC1 (W400 titanium white);

[0165] (2) The non-hiding color paint in the color paint layer uses near-infrared transmitting pigments, specifically pigments TC1 (P.B. 15:3, Blue L7085), pigment TC2 (P.R. 179, Red L3875) and pigment TC3 (P.Y. 184, Yellow L1130).

[0166] (3) The black color paint formula of the color paint layer 2 also has a pearl mica effect pigment "IRIODIN 9225" 0.35 parts.

[0167] The preparation method of the coating system and its sample is also consistent with Example 1. The obtained substrate sample with the coating system 5 of the present application is placed in a dry and clean environment for subsequent color test, spectral test and laser radar reflection experiment test.

[0168] In order to more clearly illustrate the composition of different coatings of each of the above embodiments, please refer to the following table:

[0169]

[0170] Preparation of conventional black appearance coating sample

[0171] It should be noted that in the coating system of the present comparative example 1, there is no enhanced reflective primer as claimed in the present application, and no coating composition which can form the color paint and toning primer layer as claimed in the present application is coated, but only the coating structure used by the conventional automobile original paint is used to coat the sample, thus it is only used as a comparative example.

[0172] The coating system of the present comparative example has a three-layer coating, arranged in the following order from the substrate: (1) a gray primer coating; (2) a black topcoat coating; (3) a clear coating.

[0173] Among them, the primer coating uses the gray automobile intermediate coating provided by Axalta Coating Systems; the topcoat coating uses the black topcoat provided by Axalta Coating Systems; and the clear coating uses the transparent automobile clear coating provided by Axalta Coating Systems.

[0174] The coating preparation method is as follows:

[0175] Step (1): spray a layer of gray automobile primer provided by Axalta Coating Systems on the surface of the electrophoresis sheet as the substrate, flash dry at 80°C for 15 min after leveling for 5 min, and the final dry film thickness is about 15-20 μm;

[0176] Step (2): spray the black pearl topcoat provided by Axalta Coating Systems on the surface of the coating obtained in step (1), flash dry at 80°C for 25 min after leveling for 5 min, and the dry film thickness is about 5-15 μm;

[0177] Step (3): spray the transparent automobile clear coating provided by Axalta Coating Systems on the surface of the coating obtained in step (2), and let the coating film level and dry, and the dry film thickness is about 30-40 μm;

[0178] Step (4): bake the multilayer coating system obtained in step (3) and the substrate under the same conditions (140°C) (20-30 min) to completely dry the entire coating system.

[0179] Place the obtained substrate sample with the coating system of comparative example 1 in a dry and clean environment for subsequent color test, spectral test and laser radar reflection experiment test.

[0180] Preparation of coating system using infrared reflective finish and its sample

[0181] It should be noted that in the coating system of the present comparative example, the conventional coating system of the infrared reflective coating prepared by the infrared reflective black pigment in the prior art is used, including the infrared reflective black topcoat and the varnish coating. Neither the coating composition forming the multilayer coating structure according to the present application nor the multilayer structure according to the present application is coated therein, and thus it is merely used as a comparative example.

[0182] The coating system according to the present comparative example 2 is arranged in the following order from the substrate: (1) black topcoat; (2) varnish coating.

[0183] The black topcoat is prepared by using the aforementioned paint preparation method and raw materials, and the difference from the example is that the paint topcoat pigment used in the comparative example 2 is a reflective black pigment. Black L0095.

[0184]

[0185]

[0186] The coating preparation method is as follows:

[0187] Step (1): spray a layer of the above-prepared black topcoat on the surface of the electrophoretic plate as the substrate, and flash dry at 80°C for 25 min after leveling for 5 min;

[0188] Step (2): spray the transparent automotive varnish provided by the company on the surface of the coating obtained in step (1), and let the coating film level and dry;

[0189] Step (3): bake the two layers of coating and the substrate obtained in step (2) under the same conditions (140°C) (20-30 min) to completely dry the entire coating system.

[0190] Place the obtained substrate sample with the coating system of the comparative example 2 in a dry and clean environment for subsequent color test, spectral test and laser radar reflection test.

[0191] Preparation of coating system using near-infrared transmitting color coat, without tint base coat and enhanced reflective base coat Preparation of coating system using infrared transmitting color coat and high-reflective white base coat layer and its sample

[0192] It should be noted that in the coating system of the present comparative example, the conventional coating system of the infrared reflective coating prepared by the infrared reflective black pigment in the prior art is used, including the infrared reflective black topcoat and the varnish coating. Neither the coating composition forming the multilayer coating structure according to the present application nor the multilayer structure according to the present application is coated therein, and thus it is merely used as a comparative example.

[0193] The coating system described in Comparative Example 3 has three layers of coatings, arranged in the following order from the substrate: (1) a gray basecoat; (2) a near-infrared transmitting black topcoat; and (3) a clearcoat coating.

[0194] The gray basecoat layer is prepared using a gray automotive midcoat paint provided by Axalta Coating Systems; the infrared transmitting black topcoat is prepared using the aforementioned black topcoat preparation method and raw materials; and the clearcoat coating is prepared using a clear automotive clearcoat provided by Axalta Coating Systems.

[0195] The infrared transmitting black topcoat is prepared using the aforementioned preparation method and raw materials, except that the pigment used in Comparative Example 3 is a black pigment. Black L0086.

[0196]

[0197] The coating preparation method is as follows:

[0198] Step (1): Spray a layer of gray automotive midcoat paint provided by Axalta Coating Systems on the surface of an electrophoresis plate as the substrate, and after leveling for 5 min, flash dry at 80°C for 15 min;

[0199] Step (2): Spray the infrared transmitting black topcoat prepared above on the surface of the coating obtained in step (1), and after leveling for 5 min, flash dry at 80°C for 25 min;

[0200] Step (3): Spray a clear automotive clearcoat provided by Axalta Coating Systems on the surface of the coating obtained in step (2), and after the coating film is leveled and dried;

[0201] Step (4): Bake the multilayer coating system obtained in step (3) and the substrate under the same conditions (140°C, 20-30 min) to completely dry the entire coating system.

[0202] Place the obtained substrate sample with the coating system as Comparative Example 3 in a dry and clean environment for subsequent color testing, spectral testing, and laser radar reflection experiment testing.

[0203] Color and spectral test

[0204] It should be noted that in the coating system of Comparative Example 4, a color paint prepared from an infrared anti-transmitting black pigment, a conventional white basecoat paint in the prior art, and a transparent clearcoat coating system are used. The toning basecoat described in the present application is not used, and the enhanced reflective basecoat coating described in the present application is not contained, so it is only used as a comparative example.

[0205] The coating system described in Comparative Example 4 has three layers of coatings, arranged in the following order from the substrate: (1) white basecoat; (2) near-infrared transmitting black topcoat; (3) clearcoat coating.

[0206] The white basecoat is prepared by the method and raw materials described above, except that the pigment contains only white pigments, as shown in the following table; the near-infrared transmitting black topcoat is prepared by the method described in Comparative Example 3; and the clearcoat coating is a transparent automotive clearcoat provided by Axalta Coating Systems.

[0207]

[0208]

[0209] The coating preparation method is as follows:

[0210] Step (1): spray a layer of the white basecoat prepared above on the surface of the electrophoretic plate substrate, and after leveling for 5 min, flash dry at 80°C for 15 min;

[0211] Step (2): spray the near-infrared transmitting black topcoat prepared in Comparative Example 3 on the surface of the coating obtained in Step (1), and after leveling for 5 min, flash dry at 80°C for 25 min;

[0212] Step (3): spray the transparent automotive clearcoat provided by Axalta Coating Systems on the surface of the coating obtained in Step (2), and let the coating film level and dry;

[0213] Step (4): bake the multilayer coating system obtained in Step (3) and the substrate under the same conditions (140°C, 20-30 min) to completely dry the entire coating system.

[0214] Place the substrate sample with the coating system as Comparative Example 4 in a dry and clean environment for subsequent color testing, spectral testing, and laser radar reflection experiment testing.

[0215] Laser radar reflection experiment test

[0216] The substrate samples with the coating system obtained in Examples 1-5 and Comparative Examples 1-4 are subjected to reflectance spectrum testing and color difference testing, respectively.

[0217] The reflectance spectrum is obtained by scanning the sample with a HITACHI U-4100 UV-Vis-NIR ultraviolet spectrophotometer (integrating sphere reflection mode) in the full wavelength range of 300 nm-3000 nm, and the results are baseline calibrated using a standard barium sulfate white standard plate.

[0218] Color data was measured by BYK-mac i multi-angle colorimeter, traditional five-angle color measurement mode, reading 45° L, a, b values. Among them, the degree of blackness can be represented by using L(45°) value (<10).

[0219] The reflectance TSR% of near-infrared spectrum in the solar spectrum was calculated by the method of total reflectance of near-infrared spectrum part of ISO9845-1 standard method.

[0220] Figure 2

[0221] The laser radar signal reflection intensity of the substrate samples with coating system obtained from Examples 1-5 and Comparative Examples 1-4 was tested, respectively. Among them, the laser light source of 905 nm and 1550 nm was used for testing, respectively.

[0222] See Figure 3 and Figure 2 . Figure 3 The structural diagram of the tested substrate sample is shown. Figure 4 The schematic diagram of the laser radar signal reflection intensity test method is shown.

[0223] The test method is as follows:

[0224] (1) Set the sample support 7 and the substrate sample 6 at a fixed detection distance (5 m) and height. The substrate sample 6 is placed on the sample support 7. The sample support 7 can rotate around a fixed shaft to change the incident angle of the laser;

[0225] (2) Set the laser radar support 9 and the laser radar 8, which is in the direction of the normal of the plane where the sample support 7 and the substrate sample 6 are located, and is consistent with the level and height thereof;

[0226] (3) Turn on the Velodyne 16 line (signal source 905 nm laser) laser radar and the PC device connected thereto, and run the matching software VeloView test software to read the signal intensity value returned by the sample surface on the laser radar scanning data point cloud map, and take the average of the entire panel data point intensity to obtain the relative intensity of the reflection signal;

[0227] (4) Rotate the sample support 7 around a fixed shaft to gradually change the incident angle of the signal of the laser radar 8, and test the substrate sample 6 obtained from Example 1 and Comparative Examples 1-2, and record the relative intensity of the reflection signal, and the results are shown in Table 1;

[0228] (5) Change the signal source of the laser radar, and use Titan Ml (signal source 1550 nm laser) laser radar. Test and record data in the same way, and the results are also shown in Table 1.

[0229] Table 1 Performance of Example and Comparative Example Sample Panel Color and Laser Radar Signal Reflection Performance Table

[0230]

[0231] From the above test results, it can be seen that the substrate sample panels described in Examples 1-5, which have the coating system of the present application, are coated with the multilayer structure described in the present application, including a varnish layer, a color paint layer, a toning primer layer, and an enhanced reflection primer layer, and the L(45°) value of each is less than 7, and the reflectivity of the laser radar laser signal with small angle of incidence is greater than 50%. In addition, the solar near-infrared spectrum reflectivity of Examples 1-5 is more than 40%.

[0232] On the contrary, the substrate sample panels of the coating system of Comparative Examples 1 and 3 are not coated with the multilayer structure coating described in the present application, although they also exhibit a black appearance, but the reflectivity of the laser radar laser signal with small angle of incidence on their surface is less than 20%. In addition, the solar near-infrared spectrum reflectivity of Comparative Examples 1 and 3 is less than 25%.

[0233] Comparative Examples 2 and 4 sample panels are not coated with the multilayer structure coating described in the present application, although the reflectivity of the laser radar laser signal with small angle of incidence is greater than that of Comparative Examples 1 and 2, but the L value at 45° angle is larger, which is higher than the L value of the multilayer structure coating described in the present application under the same conditions, and therefore does not exhibit the excellent black appearance similar to the multilayer structure coating described in the present application.

[0234] In addition, Figure 4 The appearance effect schematic diagram of the surface coated with the coating system of the present application is shown. As shown therein, from left to right are the coated surfaces of Comparative Example 1 (left), Example 1 (middle), and Example 5 (right).

[0235] Among them, Comparative Example 1 and Example 5 contain pearl effect pigments, while Example 1 does not contain pearl effect pigments. From Figure 5 It can be seen that the black appearance of the examples is very close to that of Comparative Example 1, and especially for solid black Example 1, its appearance is closer to black. It can be seen that whether or not the pearl effect pigment is added, the coating system described in the present application can make the coated surface exhibit an excellent black appearance.

[0236] Finally, see ​ which shows the reflectance spectrum diagram of the surface coated with the coating system of the present application.

[0237] The examples 1-5 all show high absorption (low reflectance) in the visible spectrum of 380-780 nm.

[0238] Comparative example 1 shows strong absorption (low reflectance) in the visible and near infrared spectrum of 380-2500 nm, and comparative example 3 also shows relatively low reflectance in the near infrared spectrum of 780-2500 nm.

[0239] Comparative example 2 shows significantly lower reflectance in the near infrared spectrum of 780-1000 nm than the examples of the present application, but higher reflectance in the spectrum of 1000-2500 nm.

[0240] Comparative example 4 shows higher reflectance in the near infrared spectrum of 780-2500 nm, but lower absorption in the visible spectrum of 700-780 nm than the examples of the present application.

[0241] Accordingly, the present application achieves excellent black appearance by special design of the multi-layer coating structure and selection of suitable pigments. The surface with the coating system of the present application can absorb visible light of 380-780 nm to the maximum extent, and at the same time reflect near infrared light of 780-2500 nm to the maximum extent, so that it has better performance than conventional coatings with black appearance and near infrared reflection performance, and has stronger reflection performance for detection signals using near infrared waveband as signal source (such as light signals emitted by sensors such as laser radar).

[0242] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A coating system having a multilayer structure, wherein, From the coated substrate, it is successively coated with a reinforcing reflective primer layer, a toning primer layer, a color paint layer, and a clear paint layer, wherein: The clear paint layer is a transparent coating layer, which has high transmittance in the spectral region of wavelength 380nm-2500nm; The color paint layer can absorb visible light of wavelength 380nm-780nm and transmit light in the near-infrared spectral region of 780nm-2500nm; The toning primer layer can absorb visible light of wavelength 380nm-780nm entering the coating; The reinforcing reflective primer layer can reflect light in the near-infrared spectral region of 780nm-2500nm entering the coating; so that The coating system with a multi-layer structure can reflect light in the near-infrared spectral region of 780nm-2500nm incident on the surface of the coated substrate, and can absorb light in the visible spectral region of 380nm-780nm incident on the coated surface.

2. The coating system according to claim 1, wherein, The color paint layer contains at least three non-hiding pigments that have transmittance in the near-infrared spectral region of 780nm-2500nm.

3. The coating system of claim 2, wherein, The non-hiding pigments meet the following conditions simultaneously: I. Reflectance <30% measured on black base card paper in the spectral region of 380nm-2500nm; II. Reflectance >35% measured on white base card paper in the spectral region of 780nm-2500nm.

4. The coating system according to claim 3, wherein, The non-hiding pigments meet the following conditions simultaneously: I. Reflectance <10% measured on black base card paper in the spectral region of 380nm-2500nm; II. Reflectance >50% measured on white base card paper in the spectral region of 780nm-2500nm.

5. The coating system of claim 2, wherein, The particle size of the non-hiding pigments is 0.01-0.05μm.

6. The coating system according to claim 5, wherein, The particle size of the non-hiding pigments is 0.01-0.025μm.

7. The coating system according to any one of claims 2 to 6, wherein The non-hiding pigments include a combination of at least three of indanthrone blue, Copper(II) phthalocyanine-based blue pigments, YInMn indium manganese blue, perylene-based black pigments, perylene-based red pigments, non-hiding DPP red pigments, quinacridone-based red pigments, quinophthalone-based pigments, isoindolinone yellow pigments, and benzimidazolone-based yellow-orange pigments.

8. The coating system according to claim 7, wherein, The non-hiding pigments contain a Copper(II) phthalocyanine blue pigment, a DPP transparent red pigment, and a transparent benzimidazolone or isoindolinone yellow yellow pigment.

9. The coating system of claim 1, wherein, The toning primer layer includes at least one dark cool color pigment that has transmittance in the near-infrared spectral region of 780nm-2500nm, and at least one pigment that has reflectivity in the near-infrared spectral region of 780nm-2500nm.

10. The coating system according to claim 9, wherein, The deep color and cool color pigments with high transmittance include indanthrone blue, copper (II) phthalocyanine, YInMn indium manganese blue, and perylene black pigments with black or blue-violet color tone.

11. The coating system according to claim 9, wherein, The pigments with high reflectivity in the near-infrared spectral region satisfy the condition that the reflectivity measured on a black base card in the spectral region of 780 nm to 2500 nm is > 30%.

12. The coating system of claim 11, wherein, The reflectivity measured on a black base card in the spectral region of 780 nm to 2500 nm is > 45%.

13. The coating system of claim 9, wherein, The pigments with high reflectivity in the near-infrared spectral region include titanium white pigments, barium white pigments, zinc barium white pigments, zinc oxide, lithopone, bismuth oxide pigments, zirconium oxide pigments, covering DPP red, titanium yellow pigments, bismuth vanadate yellow, benzimidazolone-based pigments, yttrium indium oxide blue pigments (YInxOy), and iron manganese titanium black CICP inorganic composite pigments.

14. The coating system according to claim 13, wherein, The pigments with high reflectivity in the near-infrared spectral region include white pigments with high reflectivity.

15. The coating system according to claim 13, wherein, The toning basecoat layer includes at least one or a combination of several of conventional titanium white pigments and special titanium white pigments with higher near-infrared reflectivity.

16. The coating system of claim 9, wherein, The enhanced reflective basecoat layer includes at least one of metal flake pigments with strong reflectivity in the near-infrared spectral region or white pigments with strong reflectivity.

17. The coating system of claim 16, wherein, The metal flake pigments with strong reflectivity include one or several of electroplated aluminum silver paste, electroless plated aluminum silver paste, silver-coated glass flakes, or mica flakes.

18. The coating system of claim 17, wherein, The electroplated aluminum silver paste is a non-floating type electroplated aluminum silver paste or a floating type electroplated aluminum silver paste.

19. A method for preparing the coating system with a multi-layer structure according to any one of claims 1-18, comprising the following steps: (1) applying an enhanced reflective basecoat on the surface of the substrate; (2) applying a toning basecoat on the coating obtained in step (1); (3) applying a pigmented topcoat on the coating obtained in step (2); (4) applying a clear topcoat on the coating obtained in step (3) and performing baking or ambient drying, thereby obtaining the coating system with a multi-layer structure.

20. A traffic facility or vehicle, wherein the surface of the traffic facility or vehicle is coated with the coating system with a multi-layer structure according to any one of claims 1-18.

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