Automobile coating, preparation method thereof and automobile

Abstract

The invention discloses an automobile coating, a preparation method of the automobile coating and an automobile. The automobile coating comprises an intermediate paint coating, a metal paint coating, a pearlescent paint coating, a single-color paint coating and a 2K varnish coating which are arranged in a stacked mode. Therefore, the paint surface perception quality of the automobile coating is greatly improved, the color saturation is high, the coating is transparent and full, the appearance is more excellent, the ripples at the edge of a reflection object image of the paint surface are tiny and neat, the paint surface is flat, bright, fine and textured, and the pursuit of consumers for high-end customized automobile coating individuation can be met.

Description

Technical Field

[0001] This application relates to the field of automotive coating processes, specifically to automotive coatings, their preparation methods, and automobiles. Background Technology

[0002] With the development of automotive painting technology, the color effects of car body paint have evolved from solid colors to metallic paints and then to pearlescent paints. The appearance of traditional cars has also progressed from a single natural color to high-gloss effects with metallic sheen, pearlescent sheen, and variations in brightness and color. The main painting steps of traditional painting processes are: pretreatment, electrophoresis, electrophoretic drying, strong cooling, intermediate coat spraying, intermediate coat drying, strong cooling, color paint spraying, pre-drying, clear coat spraying, leveling, and topcoat drying. The disadvantages of this method are: monotonous overall color, low color saturation, ordinary appearance, indistinct color changes with viewing angle, weak paint film layering and technological feel, and a dry, lackluster finish, failing to meet consumers' personalized demands for high-end customized car paint. Therefore, automotive painting technology needs further improvement.

[0003] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] In a first aspect, this application proposes an automotive coating comprising a layered intermediate coat, a metallic coat, a pearlescent coat, a monochrome coat, and a 2K clear coat. This coating significantly improves the perceived quality of the paint surface, resulting in high color saturation, a clear and full coating, a superior appearance, and fine, even edges reflecting object images. The paint surface is smooth, glossy, and has a delicate, textured finish, satisfying consumers' pursuit of personalized, high-end custom automotive coatings.

[0005] In addition, the automotive coating according to the above embodiments of this application may also have the following additional technical features: In some embodiments, the thickness of the intermediate coat is 30µm to 40µm; in other embodiments, the thickness of the intermediate coat is 35µm; in some embodiments, the thickness of the metallic paint coating is 10µm to 16µm; in other embodiments, the thickness of the metallic paint coating is 12µm; in some embodiments, the thickness of the pearlescent paint coating is 4µm to 10µm; in other embodiments, the thickness of the pearlescent paint coating is 6µm; in some embodiments, the thickness of the monochrome paint coating is 4µm to 10µm; in other embodiments, the thickness of the monochrome paint coating is 6µm; in some embodiments, the thickness of the 2K clear coat coating is 45µm to 55µm; in other embodiments, the thickness of the 2K clear coat coating is 50µm. This improves the paint surface quality and appearance of the automotive coating.

[0006] In some embodiments, the thickness uniformity σ of the intermediate coat, the metallic paint coating, the pearlescent paint coating, the monochrome paint coating, and the 2K clear coat coating is independently ≤2µm. Therefore, the surface of the automotive coating is relatively smooth, and the coating quality is high.

[0007] In a second aspect, this application proposes a method for preparing an automotive coating, comprising: sequentially applying a water-based intermediate coat to the automotive body-in-white, performing a first drying treatment, applying a water-based metallic paint, applying a water-based pearlescent paint, applying a water-based monochrome paint, applying a 2K clear coat, and performing a second drying treatment. This method facilitates obtaining an automotive coating with high perceived quality, high color saturation, transparency, fullness, and a delicate texture, satisfying consumers' pursuit of personalized high-end customized automotive coatings. Furthermore, the process is simple and easy to industrialize.

[0008] In some embodiments, the process parameters for the water-based intermediate coating spraying satisfy at least one of the following: The discharge rate of the intermediate coat paint is 250cc / min~350cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The intermediate coat paint flows completely out of the viscosity cup of type DIN-4# in 40s to 50s; in other embodiments, the flow time is 46s.

[0009] Meeting the above process parameters during water-based intermediate coating spraying helps reduce sagging, provides better edge coverage of the paint film, results in a smooth paint film surface with low roughness, and makes the paint film thickness easier to control.

[0010] In some embodiments, the conditions for the first drying process include: maintaining the temperature at 70°C to 80°C for 5 minutes, then raising the temperature to 150°C to 160°C and maintaining the drying time for 15 minutes to 22 minutes; in other embodiments, maintaining the temperature at 70°C to 80°C for 5 minutes, then raising the temperature to 150°C and maintaining the drying time for 15 minutes. This facilitates the evaporation of solvents in the paint film and the transformation of the wet paint film into a solid state.

[0011] In some embodiments, the process parameters for spraying the water-based metallic paint shall at least satisfy one of the following: The output rate of metallic paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The time for the metallic paint to completely flow out of the viscosity cup of type DIN-4# is 25s to 40s; in other embodiments, the flow time is 31s.

[0012] Meeting the above process parameters during water-based metallic paint spraying helps control the thickness and uniformity of the metallic paint coating, resulting in better paint quality and appearance.

[0013] In some embodiments, the process parameters for spraying the water-based pearlescent paint shall at least satisfy one of the following: The output rate of pearlescent paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The pearlescent paint flows completely out of a DIN-4# viscosity cup in 25 to 40 seconds; in some other embodiments, the flow time is 28 seconds.

[0014] When water-based pearlescent paint is sprayed, if the above process parameters are met, the viscosity of the pearlescent paint is moderate, the stability is high, and the dispersibility of the pearlescent powder is high, which is conducive to balancing the suspension and flowability of the pearlescent paint and achieving the dynamic shimmering effect of the pearlescent paint.

[0015] In some embodiments, the process parameters for spraying the water-based monochromatic paint shall at least satisfy one of the following: The output of single-color paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The time for the monochrome paint to completely flow out of the viscosity cup of type DIN-4# is 20s to 50s; in other embodiments, the flow time is 30s.

[0016] Meeting the above process parameters during water-based monochrome paint spraying can reduce the occurrence of show-through and sagging, thereby improving coating quality.

[0017] In some embodiments, the process parameters for the 2K clear coat spraying satisfy at least one of the following: The discharge rate of 2K varnish is 150cc / min~300cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The 2K varnish completely flows out of a viscosity cup of ISO-4# in 55s to 75s; in some other embodiments, the flow time is 64s.

[0018] Meeting the above process parameters during 2K clear coat spraying can control the thickness of the 2K clear coat, which helps reduce sagging and orange peel, and improves the gloss of the paint surface.

[0019] In some embodiments, the conditions for the second drying process include drying at a temperature of 125°C to 155°C for 15 to 30 minutes; in other embodiments, drying at a temperature of 140°C for 22 minutes. This facilitates the evaporation of solvents in the paint film and the transformation of the wet paint film into a solid state.

[0020] In some embodiments, the water-based monochrome paint undergoes a pre-drying treatment after spraying. The pre-drying treatment conditions include drying at a temperature of 70°C to 80°C for 3 to 5 minutes; in other embodiments, drying at 80°C for 5 minutes. This allows the wet film of the monochrome paint to be converted to a surface-dry state.

[0021] In some embodiments, the dehydration rate of the wet film of the monochrome paint after the pre-drying treatment is 80% to 95%; in other embodiments, the dehydration rate of the wet film of the monochrome paint is 88%. This helps to reduce pinholes or bursts in the paint film and improve the quality of the monochrome paint coating.

[0022] In some embodiments, the 2K clear coat is followed by a leveling treatment for 5 to 10 minutes; in other embodiments, the leveling treatment takes 7 minutes. This repairs spray marks and makes the paint film surface smoother.

[0023] In a third aspect, this application proposes an automobile comprising the automobile coating described in the first aspect of this application or an automobile coating prepared using the method described in the second aspect of this application. Consequently, the automobile has a more advanced appearance. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings.

[0025] Figure 1 This is a schematic diagram of the structure of an automotive coating according to an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the structure of an automotive coating according to an embodiment of this application.

[0027] Figure 3 This is a flowchart of an automotive painting process according to one embodiment of this application.

[0028] Figure 4 This is a flowchart of the automotive painting process of Comparative Example 1 of this application.

[0029] Explanation of reference numerals in the attached figures: 1-Intermediate coat, 2-Metallic paint coating, 3-Pearl paint coating, 4-Monochrome paint coating, 5-2K clear varnish coating, 6-Pretreatment and electrophoretic layer. Detailed Implementation

[0030] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0032] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0033] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0034] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. "First feature" and "second feature" may include one or more of the indicated feature.

[0036] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0037] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0038] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0039] In a first aspect of this application, an automotive coating is proposed, with reference to Figure 1The automotive coating comprises a layered intermediate coat 1, a metallic paint coating 2, a pearlescent paint coating 3, a monochrome paint coating 4, and a 2K clear coat coating 5. The intermediate coat enhances the adhesion and smoothness of the overall coating. The metallic paint coating improves the metallic luster and depth of the car's surface; due to the addition of metallic powder, the metallic paint has increased hardness, making the surface harder, more wear-resistant, and less prone to scratches. Furthermore, the gloss and color depth of the coating change with the incident light and viewing angle, creating rich visual effects and allowing the car to present different appearances under different lighting conditions and viewing angles. The pearlescent paint coating exhibits different glosses and colors under different lighting conditions and viewing angles, creating rich visual layers and is less prone to fading, chalking, and cracking, demonstrating excellent weather resistance. The monochrome paint coating has a uniform and consistent color. The 2K clear coat coating has high hardness, maintaining the integrity of the coating surface, reducing the risk of paint damage, and enhancing the overall appearance and texture of the vehicle. With the above-mentioned coating structure, the perceived quality of the car paint coating is greatly improved, the color saturation is high, the coating is transparent and full, the appearance is more superior, the reflection of objects on the paint surface has small and neat edges with ripples, the paint surface is smooth and bright, delicate and textured, which can meet consumers' pursuit of high-end customized car paint personalization.

[0040] In addition, the automotive coating according to the above embodiments of this application may also have the following additional technical features: In some embodiments, refer to Figure 2 The automotive coating also includes a pretreatment layer and an electrophoretic layer 6. The electrophoretic layer is mainly formed on the metal surface by electrochemical deposition to create a dense anti-corrosion layer, providing a uniform conductive substrate for subsequent spraying.

[0041] In some embodiments, the thickness of the intermediate coat is 30µm to 40µm, for example, 30µm, 32µm, 34µm, 36µm, 38µm, or 40µm; in other embodiments, the thickness of the intermediate coat is 35µm; in some embodiments, the thickness of the metallic paint coating is 10µm to 16µm, for example, 10µm, 11µm, 12µm, 13µm, 14µm, 15µm, or 16µm; in other embodiments, the thickness of the metallic paint coating is 12µm; in some embodiments, the thickness of the pearlescent paint coating is 4µm to 10µm, for example, 4µm, 5µm, or 10µm. The thickness of the pearlescent paint coating is 6µm, etc.; in some embodiments, the thickness of the single-color paint coating is 4µm to 10µm, for example, 4µm, 5µm, 6µm, 7µm, 8µm, 9µm, or 10µm; in other embodiments, the thickness of the single-color paint coating is 6µm; in some embodiments, the thickness of the 2K clear coat coating is 45µm to 55µm, for example, 45µm, 48µm, 50µm, 52µm, or 55µm; in other embodiments, the thickness of the 2K clear coat coating is 50µm. Meeting the above thickness requirements is beneficial to improving the paint surface quality and appearance of the automotive coating.

[0042] In some embodiments, the thickness uniformity σ of the intermediate coat, metallic paint coating, pearlescent paint coating, monochrome paint coating, and 2K clear coat coating is independently ≤2µm, for example, it can be 0.1µm, 0.1µm, 0.3µm, 0.5µm, 0.8µm, 1µm, 1.1µm, 1.3µm, 1.5µm, 1.8µm, or 2µm, etc. Therefore, the surface of the automotive coating is relatively smooth, and the coating quality is high.

[0043] In a second aspect of this application, a method for preparing an automotive coating is proposed, namely a 5C2B spraying process (the so-called 5C2B coating process: C stands for Coating and B stands for Bake; 5C2B means spraying 5 times and drying 2 times), see reference. Figure 3 The method includes the following steps: S1: Water-based intermediate coat spraying.

[0044] In this application, before applying the water-based intermediate coat, the vehicle body is pretreated and electrophoretically coated. The pretreatment removes oil, rust, and oxide layers from the metal surface of the vehicle body and forms a uniform phosphate film, which enhances the adhesion and corrosion resistance of the electrophoretic layer.

[0045] In some embodiments, before the electrophoretic car body enters the intermediate coat spray booth, the interior and exterior surfaces of the car body need to be wiped clean with an adhesive cloth. After wiping, the car body is clean and free of floating dust, impurities, and particles. After wiping, the intermediate coat of the car body is applied using an automatic electrostatic rotary cup coating system, with one coat applied.

[0046] In some embodiments, the process parameters for water-based intermediate coating spraying must meet at least one of the following: The discharge rate of the intermediate coat is 250cc / min to 350cc / min (such as 250cc / min, 280cc / min, 300cc / min, 320cc / min or 350cc / min, etc.). The thickness of the intermediate coat can be adjusted by controlling the discharge rate of the intermediate coat.

[0047] The spray width is 30cm~40cm (e.g., 30cm, 32cm, 34cm, 36cm, 38cm, or 40cm), the coating distance is 25cm~30cm (e.g., 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm), and the coating overlap rate is 66%~75% (e.g., 66%, 68%, 70%, 72%, or 75%). This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0048] The intermediate coat paint completely flows out of the DIN-4# viscosity cup in 40-50 seconds (i.e., the application viscosity range of the intermediate coat paint is 40-50 seconds), for example, 40 seconds, 42 seconds, 44 seconds, 46 seconds, 48 ​​seconds, or 50 seconds; in other embodiments, the flow time is 46 seconds. Therefore, the paint film has good edge coverage, a smooth surface, low roughness, and easily controllable thickness.

[0049] Meeting the above process parameters during water-based intermediate coating spraying helps reduce sagging, provides better edge coverage of the paint film, results in a smooth paint film surface with low roughness, and makes the paint film thickness easier to control.

[0050] In some embodiments, the process parameters for water-based intermediate coating spraying further include: The temperature in the intermediate coat spray booth is 21℃~25℃ (e.g., 21℃, 22℃, 23℃, 24℃, or 25℃), the relative humidity is 60%~70% (e.g., 60%, 62%, 64%, 66%, 68%, or 70%), and the wind speed is 0.3m / s~0.4m / s (e.g., 0.3m / s, 0.32m / s, 0.34m / s, 0.36m / s, 0.38m / s, or 0.4m / s). Therefore, the evaporation rate of moisture in the intermediate coat is moderate, resulting in a high-quality paint film.

[0051] The intermediate coat should be applied at a temperature of 22℃~24℃ (e.g., 22℃, 23℃, or 24℃) and have a pH value of 8.4~8.6 (e.g., 8.4, 8.5, or 8.6). Therefore, the intermediate coat has suitable viscosity and good film coverage and uniformity.

[0052] The rotary cup rotation speed is 35,000 rpm to 60,000 rpm (e.g., 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm, 55,000 rpm, or 60,000 rpm, etc.), the shaping air velocity is 260 / 130 NL / min (i.e., the air velocity on the outside of the rotary cup is 260 NL / min, and the air velocity on the inside is 130 NL / min), and the application voltage is -75KV. This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0053] In some embodiments, the water-based intermediate coat is flash-dryed and leveled for 5 to 12 minutes (e.g., 5 minutes, 7 minutes, 9 minutes, or 12 minutes) after spraying. In other embodiments, the flash-drying and leveling is performed for 8 minutes. This allows most of the solvent in the intermediate coat to evaporate, reducing pinholes and bubbles caused by rapid solvent evaporation during direct drying, while also reducing sagging caused by wet film flow, thereby improving the quality of the paint surface.

[0054] In some embodiments, the total thickness of the electrophoretic layer and the intermediate coating is ≥55μm, for example, it can be 55μm, 56μm, 57μm, 58μm, 59μm or 60μm, etc.; the film performance quality is: adhesion (cross-cut test) ≤1 grade, impact strength ≥294N.cm, cupping ≥4 mm, stone impact resistance ≤2 grade.

[0055] S2: First drying process.

[0056] In some embodiments, the conditions for the first drying process include: maintaining an ambient temperature of 70°C to 80°C (e.g., 70°C, 72°C, 74°C, 76°C, 78°C, or 80°C) for 5 minutes, followed by raising the temperature to 150°C to 160°C (e.g., 150°C, 152°C, 154°C, 156°C, 158°C, or 160°C) and maintaining the temperature for 15 minutes to 22 minutes (e.g., 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, 21 minutes, or 22 minutes); in other embodiments, maintaining an ambient temperature of 70°C to 80°C for 5 minutes, followed by raising the temperature to 150°C and maintaining the temperature for 15 minutes. This facilitates the evaporation of solvents from the paint film and the transformation of the wet paint film into a solid state.

[0057] S3: Water-based metallic paint spraying.

[0058] In some embodiments, before spraying the water-based metallic paint, defects in the intermediate coat are rounded using P600-P800 sandpaper, and the interior and exterior surfaces of the vehicle body are blown and wiped clean to ensure that the surfaces are free of dust, impurities, and particles. To ensure the overall color appearance of the vehicle, the water-based metallic paint is applied using an automatic electrostatic rotary cup coating system, with one coat applied at a time. In some embodiments, the process parameters for water-based metallic paint spraying must meet at least one of the following: The output rate of metallic paint is 120cc / min to 250cc / min, for example, it can be 120cc / min, 140cc / min, 160cc / min, 180cc / min, 200cc / min, 220cc / min or 250cc / min, etc. The thickness of the metallic paint coating can be adjusted by controlling the output rate of metallic paint.

[0059] The spray width is 30cm~40cm (e.g., 30cm, 32cm, 34cm, 36cm, 38cm, or 40cm), the coating distance is 25cm~30cm (e.g., 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm), and the coating overlap rate is 66%~75% (e.g., 66%, 68%, 70%, 72%, or 75%). This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0060] The metallic paint completely flows out of the DIN-4# viscosity cup in 25 to 40 seconds, for example, 25, 30, 35, or 40 seconds (i.e., the application viscosity range of the metallic paint is 25 to 40 seconds); in some other embodiments, the flow time is 31 seconds. This prevents the formation of uneven orange peel texture and results in a better metallic sheen.

[0061] Meeting the above process parameters during water-based metallic paint spraying helps control the thickness and uniformity of the metallic paint coating, resulting in better paint quality and appearance.

[0062] In some embodiments, the process parameters for water-based metallic paint spraying further include: The temperature in the metallic paint spray booth is 21℃~25℃ (e.g., 21℃, 22℃, 23℃, 24℃, or 25℃), the relative humidity is 60%~70% (e.g., 60%, 62%, 64%, 66%, 68%, or 70%), and the wind speed is 0.3m / s~0.4m / s (e.g., 0.3m / s, 0.32m / s, 0.34m / s, 0.36m / s, 0.38m / s, or 0.4m / s). Therefore, the evaporation rate of moisture in the metallic paint is relatively moderate, resulting in a high-quality paint film.

[0063] The temperature range for metallic paint is 22℃~24℃ (e.g., 22℃, 23℃, or 24℃), and the pH value is 7.9~8.1 (e.g., 7.9, 8, or 8.1). Therefore, metallic paint has suitable viscosity and good film coverage and uniformity.

[0064] The rotary cup rotation speed is 35,000 rpm to 60,000 rpm (e.g., 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm, 55,000 rpm, or 60,000 rpm, etc.), the shaping air velocity is 260 / 130 NL / min (i.e., the air velocity on the outside of the rotary cup is 260 NL / min, and the air velocity on the inside is 130 NL / min), and the application voltage is -75KV. This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0065] S4: Water-based pearlescent paint spraying.

[0066] In this application, to ensure the overall color appearance of the vehicle, the water-based pearlescent paint is applied using an automatic electrostatic rotary cup coating system, with one coat applied.

[0067] In some embodiments, the process parameters for spraying water-based pearlescent paint shall at least satisfy one of the following: The discharge rate of pearlescent paint is 120cc / min to 250cc / min, for example, it can be 120cc / min, 140cc / min, 160cc / min, 180cc / min, 200cc / min, 220cc / min or 250cc / min, etc. The thickness of the pearlescent paint coating can be adjusted by controlling the discharge rate of pearlescent paint.

[0068] The spray width is 30cm~40cm (e.g., 30cm, 32cm, 34cm, 36cm, 38cm, or 40cm), the coating distance is 25cm~30cm (e.g., 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm), and the coating overlap rate is 66%~75% (e.g., 66%, 68%, 70%, 72%, or 75%). This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0069] The pearlescent paint completely flows out of the DIN-4# viscosity cup in 25-40 seconds (i.e., the application viscosity range of the pearlescent paint is 25-40 seconds), for example, 25 seconds, 30 seconds, 35 seconds, or 40 seconds; in some embodiments, the flow time is 28 seconds. This helps to balance the suspension and flowability of the pearlescent paint, ensuring that the pearlescent powder is evenly dispersed and arranged in an orderly manner after spraying.

[0070] When water-based pearlescent paint is sprayed, if the above process parameters are met, the viscosity of the pearlescent paint is moderate, the stability is high, and the dispersibility of the pearlescent powder is high, which is conducive to balancing the suspension and flowability of the pearlescent paint and achieving the dynamic shimmering effect of the pearlescent paint.

[0071] In some embodiments, the process parameters for water-based pearlescent paint spraying further include: The temperature in the pearlescent paint spray booth is 21℃~25℃ (e.g., 21℃, 22℃, 23℃, 24℃, or 25℃), the relative humidity is 60%~70% (e.g., 60%, 62%, 64%, 66%, 68%, or 70%), and the wind speed is 0.3m / s~0.4m / s (e.g., 0.3m / s, 0.32m / s, 0.34m / s, 0.36m / s, 0.38m / s, or 0.4m / s). Therefore, the evaporation rate of moisture in the pearlescent paint is relatively moderate, resulting in a high-quality paint film.

[0072] Pearlescent paint has a temperature range of 22℃~24℃ (e.g., 22℃, 23℃, or 24℃) and a pH value of 7.9~8.1 (e.g., 7.9, 8, or 8.1). Therefore, pearlescent paint has a moderate viscosity, high stability, and high dispersibility of pearlescent powder, which is beneficial for improving the quality of the paint surface.

[0073] The rotary cup rotation speed is 35,000 rpm to 60,000 rpm (e.g., 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm, 55,000 rpm, or 60,000 rpm), the shaping air velocity is 260 / 130 NL / min (i.e., the air velocity on the outside of the rotary cup is 260 NL / min, and the air velocity on the inside is 130 NL / min), and the application voltage is -75KV. This ensures the integrity of the pearlescent powder and its relatively uniform distribution, which is beneficial for achieving the dynamic shimmering effect of the pearlescent paint.

[0074] S5: Water-based monochrome paint spraying.

[0075] In this application, to ensure the overall color appearance of the vehicle, the water-based single-color paint is applied using an automatic electrostatic rotary cup coating system, with one coat applied.

[0076] In some embodiments, the process parameters for spraying water-based monochrome paint shall at least satisfy one of the following: The output rate of the monochrome paint is 120cc / min to 250cc / min, for example, it can be 120cc / min, 140cc / min, 160cc / min, 180cc / min, 200cc / min, 220cc / min or 250cc / min, etc. The thickness of the monochrome paint coating can be adjusted by controlling the output rate of the monochrome paint.

[0077] The spray width is 30cm~40cm (e.g., 30cm, 32cm, 34cm, 36cm, 38cm, or 40cm), the coating distance is 25cm~30cm (e.g., 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm), and the coating overlap rate is 66%~75% (e.g., 66%, 68%, 70%, 72%, or 75%). This helps to make the paint film surface smoother, less prone to sagging or paint mist rebound, and improves the quality of the paint film.

[0078] The time for the single-color paint to completely flow out of the viscosity cup of model DIN-4# is 20s to 50s (i.e., the application viscosity range of the single-color paint is 20s to 50s), for example, it can be 20s, 25s, 30s, 35s, 40s, 45s or 50s, etc.; in some other embodiments, the flow time is 30s.

[0079] Meeting the above process parameters during water-based monochrome paint spraying can reduce the occurrence of show-through and sagging, thereby improving coating quality.

[0080] In some embodiments, the process parameters for water-based monochrome paint spraying further include: The temperature in the monochrome paint spray booth is 21℃~25℃ (e.g., 21℃, 22℃, 23℃, 24℃, or 25℃), the relative humidity is 60%~70% (e.g., 60%, 62%, 64%, 66%, 68%, or 70%), and the wind speed is 0.3m / s~0.4m / s (e.g., 0.3m / s, 0.32m / s, 0.34m / s, 0.36m / s, 0.38m / s, or 0.4m / s). Therefore, the evaporation rate of moisture in the monochrome paint is relatively moderate, resulting in a high-quality paint film.

[0081] The temperature range for monochrome paint is 22℃~24℃ (e.g., 22℃, 23℃, or 24℃), and the pH value is 7.9~8.1 (e.g., 7.9, 8, or 8.1). Therefore, monochrome paint has a relatively moderate viscosity and high stability, which is beneficial for improving paint surface quality.

[0082] The rotary cup rotation speed is 35,000 rpm to 60,000 rpm (e.g., 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm, 55,000 rpm, or 60,000 rpm), the shaping air velocity is 260 / 130 NL / min (i.e., the air velocity outside the rotary cup is 260 NL / min, and the air velocity inside the cup is 130 NL / min), and the application voltage is -75 kV. This is beneficial for improving the quality of the monochrome paint coating.

[0083] In this application, to confirm the overall color appearance of the vehicle, after the water-based monochrome paint is applied, it can maintain leveling for 1 to 2 minutes under environmental conditions of 23°C, 65% relative humidity, 0.4 m / s wind speed, and air cleanliness of 0 particles with a diameter ≥5µm.

[0084] In some embodiments, the water-based monochrome paint undergoes a pre-drying treatment after spraying. The pre-drying conditions include drying at a temperature of 70°C to 80°C (e.g., 70°C, 72°C, 74°C, 76°C, 78°C, or 80°C) for 3 to 5 minutes (e.g., 3 minutes, 4 minutes, or 5 minutes), specifically using a drying oven. In other embodiments, drying at 80°C for 5 minutes is performed. This allows the wet film of the monochrome paint to be converted to a surface-dry state.

[0085] In some embodiments, the dehydration rate of the wet film of the monochrome paint after pre-drying treatment is 80% to 95%, for example, it can be 80%, 85%, 90% or 95%; in other embodiments, the dehydration rate of the wet film of the monochrome paint is 88%. This helps to reduce pinholes or bursts in the paint film and improve the quality of the monochrome paint coating.

[0086] S6: 2K clear coat spraying.

[0087] In this application, to ensure the overall color and appearance of the vehicle, the 2K clear coat is applied using an automatic electrostatic rotary cup coating system, with one coat applied.

[0088] In some embodiments, the process parameters for 2K clear coat spraying must meet at least one of the following: The discharge rate of 2K varnish is 150cc / min to 300cc / min, for example, it can be 150cc / min, 200cc / min, 250cc / min or 300cc / min. This allows for control of the 2K varnish thickness and improves curing uniformity.

[0089] The spray width is 30cm~40cm (e.g., 30cm, 32cm, 34cm, 36cm, 38cm, or 40cm), the coating distance is 25cm~30cm (e.g., 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm), and the coating overlap rate is 66%~75% (e.g., 66%, 68%, 70%, 72%, or 75%). This improves the smoothness and coverage of the 2K clear coat.

[0090] The time for 2K varnish to completely flow out of a viscosity cup of model ISO-4# is 55s to 75s (i.e., the application viscosity range of 2K varnish is 55s to 75s), for example, it can be 55s, 60s, 65s, 70s or 75s, etc.; in other embodiments, the flow time is 64s.

[0091] Meeting the above process parameters during 2K clear coat spraying can control the thickness of the 2K clear coat, which helps reduce sagging and orange peel, and improves the gloss of the paint surface.

[0092] In some embodiments, the process parameters for 2K clear coat spraying further include: The temperature in the 2K varnish spray booth is 21℃~25℃ (e.g., 21℃, 22℃, 23℃, 24℃, or 25℃), the relative humidity is 60%~70% (e.g., 60%, 62%, 64%, 66%, 68%, or 70%), and the wind speed is 0.2m / s~0.3m / s (e.g., 0.2m / s, 0.22m / s, 0.24m / s, 0.26m / s, 0.28m / s, or 0.3m / s). Therefore, the evaporation rate of moisture in the 2K varnish is relatively moderate, resulting in a high-quality paint film.

[0093] The optimal temperature range for 2K varnish is 21℃~25℃, such as 21℃, 22℃, 23℃, 24℃, or 25℃. Therefore, the viscosity of 2K varnish is quite suitable.

[0094] The rotary cup rotation speed is 30,000 rpm to 60,000 rpm (e.g., 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm, 55,000 rpm, or 60,000 rpm, etc.), the shaping air velocity is 300 / 150 NL / min (i.e., the air velocity on the outside of the rotary cup is 300 NL / min, and the air velocity on the inside is 150 NL / min), the application voltage is -70KV, and the spraying air pressure is 0.45MPa to 0.55MPa (e.g., 0.45MPa, 0.48MPa, 0.5MPa, 0.52MPa, or 0.55MPa, etc.). This is beneficial to the quality of the 2K clear coat.

[0095] In some embodiments, a leveling treatment is performed after the 2K clear coat is applied. The leveling treatment time is 5 to 10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes; in other embodiments, the leveling treatment time is 7 minutes. This can repair spray marks and make the paint film surface smoother.

[0096] S7: Second drying process.

[0097] In some embodiments, the conditions for the second drying process include drying at a temperature of 125°C to 155°C (e.g., 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, or 155°C, etc.) for 15 min to 30 min (e.g., 15 min, 20 min, 25 min, or 30 min, etc.); in other embodiments, drying at 140°C for 22 min. This facilitates the evaporation of solvents in the paint film and the transformation of the wet paint film into a solid state.

[0098] In this application, spray width refers to the width of the atomized spray formed after the paint is sprayed from the rotary cup; coating distance refers to the vertical distance between the rotary cup nozzle and the vehicle surface; coating overlap rate is the percentage of the overlap between adjacent spray trajectories to the total spray width.

[0099] It should be noted that water-based intermediate coating spraying, water-based metallic paint spraying, water-based pearlescent paint spraying, water-based monochrome paint spraying, and 2K clear coat spraying can be carried out in the same spray booth or in their respective spray booths. This application does not impose specific limitations and can be flexibly selected according to specific production needs.

[0100] This application uses the above method to superimpose metallic paint coating and pearlescent paint coating, which is beneficial to obtain a car coating with high perceived quality, high color saturation, transparency and fullness, and delicate texture. It can meet consumers' pursuit of high-end customized car painting personalization, and the process is simple and easy to realize industrial production.

[0101] In a third aspect of this application, a vehicle is provided, comprising the automotive coating of the first aspect of this application or an automotive coating prepared using the method of the second aspect of this application. Thus, the vehicle has a more advanced appearance.

[0102] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0103] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0104] Example 1 This embodiment provides a 5C2B high-end customized high-saturation color coating process for automobiles. The process includes: water-based light gray intermediate coat spraying → drying → water-based elegant gray metallic paint spraying → water-based elegant gray pearlescent paint spraying → water-based elegant gray monochrome paint spraying → pre-drying → 2K clear coat spraying → leveling → drying. Detailed implementation process is as follows: 1. Water-based light gray intermediate coat spraying Before the electrophoretic coating process begins, the interior and exterior surfaces of the car body must be cleaned with an tack cloth, ensuring the body is free of dust, impurities, and particles. The intermediate coat is applied using an automatic electrostatic rotary cup coating system, with one coat applied at a time. During application, the spray booth temperature is maintained at 23°C, relative humidity at 65%, air velocity at 0.35 m / s, intermediate coat temperature at 23°C, pH at 8.6, output at 280 cc / min, rotary cup speed at 40,000 rpm, shaping air at 260 / 130 NL / min, spray width at 35 cm, coating distance at 30 cm, coating overlap at 66%, application voltage at -75 KV, and intermediate coat viscosity range at 46 s (23°C, DIN-4#). After application, the car body must undergo flash drying and leveling for 8 minutes.

[0105] II. First Drying Treatment After the intermediate coat has finished flash-drying and leveling, the wet paint film on the car body needs to be heated in a drying oven to turn it into a solid state. During the drying process, the car body temperature must be maintained at 80℃ for 5 minutes, and then slowly increased to 155℃ and maintained for 15 minutes.

[0106] Intermediate coating film thickness: Dry film thickness is 35μm, total film thickness of electrophoresis + intermediate coating is 55-58μm. Film performance quality: Adhesion (cross-cut test) is grade 0, impact strength is 490N.cm, cupping is 7.2mm, and stone chip resistance is grade 1.

[0107] III. Water-based Elegant Gray Metallic Paint Spraying Before spraying, use P600-P800 sandpaper to round and polish any defects in the intermediate coating, and blow and wipe the interior and exterior surfaces of the vehicle body clean to ensure they are free of dust, impurities, and particles. To ensure the overall color appearance of the vehicle, the water-based Elegant Gray Metallic paint is applied using an automatic electrostatic rotary cup coating system. One coat is applied. During the spraying process, maintain the spray booth temperature at 23℃, relative humidity at 65%, air velocity at 0.35m / s, paint temperature at 23℃, pH at 8.1, output at 180cc / min, rotary cup speed at 45000rpm, shaping air at 260 / 130NL / min, spray width at 40cm, coating distance at 30cm, coating overlap at 66%, application voltage at -75KV, and the Elegant Gray Metallic paint application viscosity range at 31s (23℃, DIN-4# measurement). The dry film thickness of the Elegant Gray Metallic paint is 12µm.

[0108] IV. Water-based elegant gray pearlescent paint spraying The water-based elegant grey pearlescent paint is applied using an automatic electrostatic rotary cup coating system. Each coat is applied in one pass. During the application process, the spray booth temperature is maintained at 23℃, relative humidity at 65%, and air velocity at 0.35 m / s. The paint temperature is maintained at 23℃, pH at 8.0, discharge rate at 180 cc / min, rotary cup speed at 45,000 rpm, shaping air at 260 / 130 NL / min, spray width at 40 cm, coating distance at 30 cm, coating overlap at 66%, and application voltage at -75 KV. The application viscosity range for the elegant grey pearlescent paint is 28 s (measured at 23℃, DIN-4#). The dry film thickness of the elegant grey pearlescent paint is 6 µm.

[0109] V. Spraying of Water-Based Elegant Gray Monochrome Paint To ensure the overall color appearance of the vehicle, the water-based Elegant Gray monochrome paint is applied using an automatic electrostatic rotary cup coating system. One coat is applied. During the coating process, the spray booth temperature is maintained at 23℃, the relative humidity at 65%, the air velocity at 0.35 m / s, the Elegant Gray monochrome paint temperature is maintained at 23℃, the pH value is 8.0, the output is 180 cc / min, the rotary cup speed is 45000 rpm, the shaping air is 260 / 130 NL / min, the spray width is 40 cm, the coating distance is 30 cm, the coating overlap rate is 66%, the application voltage is -75 KV, and the application viscosity of the Elegant Gray monochrome paint is 30s (at 23℃). The dry film thickness of the water-based Elegant Gray monochrome paint is 6 μm.

[0110] VI. Pre-drying treatment After all three coats of paint have been applied, maintain leveling for 1 minute under environmental conditions of 23°C, 65% relative humidity, 0.4m / s wind speed, and 0 particles with a diameter ≥5µm.

[0111] After leveling, the car body is heated in a drying oven to convert the wet paint film to a surface-dry state. During the drying process, the car body temperature is 80℃ and the drying time is 5 minutes. After pre-drying, the dehydration rate of the single-color paint reaches 88.5%.

[0112] VII. 2K Clear Coat Spraying After the paint on the car body cools to below 30°C, 2K clear coat is applied. The 2K clear coat is applied using an automatic electrostatic rotary cup coating system, with one coat applied at a time. During the application process, the spray booth temperature is 23°C, the relative humidity is 65%, the air velocity is 0.35 m / s, the 2K clear coat temperature is maintained at 23°C, the output is 200 cc / min, the rotary cup speed is 35,000 rpm, the shaping air is 300 / 150 NL / min, the spray width is 40 cm, the coating distance is 30 cm, the coating overlap is 66%, the application voltage is -70 KV, the spray air pressure is maintained at 0.50 MPa, and the 2K clear coat application viscosity is 64 s (at 23°C). The dry film thickness of the 2K clear coat is 50 µm.

[0113] 8. Leveling treatment After applying 2K clear coat, the car body undergoes flash drying and leveling for 7 minutes.

[0114] IX. Second Drying Treatment After leveling, the car body is heated in a drying oven to convert the wet film into a solid state. The topcoat is dried at 140°C for 22 minutes.

[0115] Example 2 This embodiment provides a 5C2B high-end customized high-saturation color coating process for automobiles. The process includes: spraying a water-based light gray intermediate coat → drying → spraying a water-based pearlescent white metallic paint → spraying a water-based pearlescent white pearlescent paint → spraying a water-based pearlescent white monochrome paint → pre-drying → spraying a 2K clear coat → leveling → drying. Detailed implementation process is as follows: 1. Water-based light gray intermediate coat spraying Same as Example 1.

[0116] II. First Drying Treatment The difference from Example 1 is that the total coating thickness of electrophoresis + intermediate coating is 55-57 μm; the coating performance quality is: cupping is 7.5 mm.

[0117] III. Water-based pearlescent white metallic paint spraying The difference from Example 1 is that the elegant gray metallic paint is replaced with pearlescent white metallic paint; the pH of the pearlescent white metallic paint is 8, and the application viscosity range of the pearlescent white metallic paint is 30s (measured at 23°C, DIN-4#). The dry film thickness of the pearlescent white metallic paint is 13µm.

[0118] IV. Water-based pearlescent white pearlescent paint spraying The difference from Example 1 is that the elegant gray pearlescent paint is replaced with pearl white pearlescent paint; the application viscosity range of the pearl white pearlescent paint is 27s (23℃, measured by DIN-4#).

[0119] V. Spraying of water-based pearlescent white monochrome paint The difference from Example 1 is that the elegant gray monochrome paint is replaced with pearl white monochrome paint; the application viscosity of the pearl white monochrome paint is 29s (measured at 23°C, DIN-4#).

[0120] VI. Pre-drying treatment The difference from Example 1 is that the dehydration rate of the monochrome paint after pre-drying reaches 89%.

[0121] VII. 2K Clear Coat Spraying Same as Example 1.

[0122] 8. Leveling treatment Same as Example 1.

[0123] IX. Second Drying Treatment Same as Example 1.

[0124] Example 3 This embodiment provides a 5C2B high-end customized high-saturation color coating process for automobiles. The process includes: spraying a water-based light gray intermediate coat → drying → spraying a water-based alluring red metallic paint → spraying a water-based alluring red pearlescent paint → spraying a water-based alluring red monochrome paint → pre-drying → spraying a 2K clear coat → leveling → drying. Detailed implementation process is as follows: 1. Water-based light gray intermediate coat spraying Same as Example 1.

[0125] II. First Drying Treatment The difference from Example 1 is that the total coating thickness of electrophoresis + intermediate coating is 56-59 μm; the coating performance quality is: cupping is 7.8 mm.

[0126] III. Water-based Charming Red Metallic Paint Spraying The difference from Example 1 is that the elegant gray metallic paint is replaced with charming red metallic paint; the dry film thickness of the charming red metallic paint is 11µm.

[0127] IV. Water-based Charming Red Pearl Paint Spraying The difference from Example 1 is that the elegant gray pearlescent paint is replaced with charming red pearlescent paint; the pH value of the charming red pearlescent paint is 8.1.

[0128] V. Water-based Charming Red Monochrome Paint Spraying The difference from Example 1 is that the elegant gray monochrome paint is replaced with charming red monochrome paint; the pH value of the charming red monochrome paint is 8.1.

[0129] VI. Pre-drying treatment The difference from Example 1 is that the dehydration rate of the monochrome paint after pre-drying reaches 90.0%.

[0130] VII. 2K Clear Coat Spraying Same as Example 1.

[0131] 8. Leveling treatment Same as Example 1.

[0132] IX. Second Drying Treatment Same as Example 1.

[0133] Comparative Example 1 like Figure 4 As shown, the preparation process is the same as in Example 1, except that metallic paint and pearlescent paint were not applied.

[0134] The results showed that the body color of Comparative Example 1 was monotonous, with low color saturation, and was ordinary. The paint film lacked depth and technological feel, and the paint surface was dry and not full enough.

[0135] Table 1 below shows the paint coating quality performance of the high-end customized 5C2B coating process in the embodiments of this application. The test results lead the industry product quality technical standards and reach the international advanced level. The test results of Examples 1 to 3 all meet the requirements of Table 1.

[0136] Table 1. Coating performance test methods and results

[0137] In summary, the painting process described in this application significantly improves the perceived quality of the vehicle's paint surface, resulting in high color saturation and vibrant, rich colors. The paint reflects images of objects with minimal and neat edge ripples, approaching a mirror-like finish. Visually, the paint appears mirror-like and translucent, like porcelain, exhibiting a luxurious, pearl-like texture while meeting the quality standards for the finest artistic paint finishes. Furthermore, the paint has good thickness and high coating quality, making it suitable for personalized, high-end customized flagship luxury vehicle body painting.

[0138] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An automotive coating, characterized in that, It includes a layered intermediate coat, a metallic coat, a pearlescent coat, a monochrome coat, and a 2K clear coat.

2. The automotive coating according to claim 1, characterized in that, The thickness of the intermediate coating is 30µm~40µm, preferably 35µm; and / or, The thickness of the metallic paint coating is 10µm to 16µm, preferably 12µm; and / or, The thickness of the pearlescent coating is 4µm to 10µm, preferably 6µm; and / or, The thickness of the monochrome paint coating is 4µm to 10µm, preferably 6µm; and / or, The thickness of the 2K clear coat is 45µm to 55µm, preferably 50µm.

3. The automotive coating according to claim 1 or 2, characterized in that, The thickness uniformity σ of each of the intermediate coating, the metallic coating, the pearlescent coating, the monochrome coating, and the 2K clear coat is ≤2µm.

4. A method for preparing the automotive coating according to any one of claims 1 to 3, characterized in that, include: The car body-in-white is sequentially coated with water-based intermediate coat, first drying treatment, water-based metallic paint, water-based pearlescent paint, water-based monochrome paint, 2K clear coat, and second drying treatment.

5. The method according to claim 4, characterized in that, The process parameters for the water-based intermediate coating spraying must meet at least one of the following: The discharge rate of the intermediate coat paint is 250cc / min~350cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The intermediate coating paint flows completely out of the viscosity cup of model DIN-4# in 40s to 50s, preferably 46s.

6. The method according to claim 4 or 5, characterized in that, The conditions for the first drying process include: maintaining the temperature at 70°C to 80°C for 5 minutes, then raising the temperature to 150°C to 160°C and maintaining the drying time for 15 minutes to 22 minutes; preferably, maintaining the temperature at 70°C to 80°C for 5 minutes, then raising the temperature to 150°C and maintaining the drying time for 15 minutes.

7. The method according to claim 6, characterized in that, The process parameters for spraying the water-based metallic paint must meet at least one of the following: The output rate of metallic paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The time for the metallic paint to completely flow out of the viscosity cup of model DIN-4# is 25s to 40s, preferably 31s.

8. The method according to claim 7, characterized in that, The process parameters for spraying the water-based pearlescent paint must meet at least one of the following: The output rate of pearlescent paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The pearlescent paint flows completely from the viscosity cup of model DIN-4# in 25s to 40s, preferably 28s.

9. The method according to claim 8, characterized in that, The process parameters for spraying the water-based monochrome paint must meet at least one of the following: The output of single-color paint is 120cc / min~250cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The time for the monochrome paint to completely flow out of the viscosity cup of model DIN-4# is 20s to 50s, preferably 30s.

10. The method according to claim 9, characterized in that, The process parameters for the 2K clear coat spraying must meet at least one of the following: The discharge rate of 2K varnish is 150cc / min~300cc / min; The spray width is 30cm~40cm, the coating distance is 25cm~30cm, and the coating overlap rate is 66%~75%; The 2K varnish flows completely from the viscosity cup of model ISO-4# in 55s to 75s, preferably 64s.

11. The method according to claim 10, characterized in that, The conditions for the second drying process include drying at a temperature of 125°C to 155°C for 15 to 30 minutes, preferably drying at a temperature of 140°C for 22 minutes.

12. The method according to claim 4, characterized in that, The water-based monochrome paint is pre-dried after spraying. The pre-drying conditions include drying at 70℃~80℃ for 3min~5min, preferably at 80℃ for 5min.

13. The automotive painting process according to claim 12, characterized in that, The dehydration rate of the pre-drying treated monochrome paint wet film is 80%~95%, preferably 88%.

14. The method according to claim 4 or 10, characterized in that, After the 2K clear coat is sprayed, a leveling treatment is performed for 5 to 10 minutes, preferably 7 minutes.

15. A car, characterized in that, The automotive coating includes the automotive coating described in any one of claims 1 to 3 or the automotive coating prepared by the method described in any one of claims 4 to 14.

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