Automobile color coating and method for preparing the same

Abstract

The present application relates to the technical field of automobile color coating, and specifically discloses an automobile color coating and a preparation method thereof. From top to bottom, the automobile color coating comprises a varnish layer, a photonic crystal film and a frosted metal layer in sequence; the photonic crystal film comprises a micro-nano structure; the micro-nano structure comprises at least one of a multilayer film structure, a nano-particle structure, a two-dimensional hole structure, a three-dimensional hole structure and a nano-pillar array structure; and the multilayer film structure is formed by alternately stacking 15-30 layers of sheet materials. The automobile color coating does not rely on light absorption to present color, but generates color through light reflection and interference, so that the absorption of solar energy is greatly reduced. This helps to reduce the temperature of the automobile surface, reduce the load of the air conditioning system in the vehicle, and further improve the energy efficiency of the vehicle, reduce fuel consumption or electric energy consumption. These advantages not only improve the environmental performance of the automobile, but also increase the comfort of driving, and meet the comprehensive requirements of modern automobile design for beauty, practicality and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of automotive color coating technology, specifically to an automotive color coating and its preparation method. Background Technology

[0002] The color of a car directly affects its aesthetic appearance, thus a variety of color options can meet the needs of a wider range of people. Car colors are primarily achieved through paint pigments, the color of which depends mainly on the inherent properties of the material itself. This characteristic results in a relatively limited color range, making it difficult to achieve certain specific, very vibrant, or special effects. Furthermore, pigments are prone to fading due to prolonged exposure to ultraviolet radiation, climate change, and time, leading to a decrease in color saturation. In addition, based on the principle of pigment color formation, pigment materials absorb specific wavelengths of light and reflect or transmit other wavelengths to create color. Therefore, pigments themselves absorb a certain amount of visible and near-infrared energy, generating high temperatures that heat the car and increase energy consumption. High temperatures can also accelerate the aging and deterioration of the paint, shortening its lifespan and increasing maintenance and repair costs.

[0003] Therefore, it is necessary to provide an automotive color coating and its preparation method to offer automobiles a richer and more stable color selection, while significantly reducing solar energy absorption, lowering the temperature of the automobile surface, and improving energy efficiency. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes an automotive color coating and its preparation method, which provides automobiles with richer and more stable color choices, while significantly reducing solar energy absorption, lowering the temperature of the automobile surface, and improving energy efficiency.

[0005] A first aspect of the present invention provides a color coating for automobiles.

[0006] Specifically, from top to bottom, it includes a clear varnish layer, a photonic crystal film, and a frosted metal layer;

[0007] The photonic crystal film comprises micro- and nano-structures;

[0008] The micro / nanostructures include at least one of the following: multilayer film structure, nanoparticle structure, two-dimensional porous structure, three-dimensional porous structure, and nanopillar array structure.

[0009] The multilayer membrane structure is composed of 15 to 30 layers of sheet material stacked alternately.

[0010] Preferably, the thickness of the sheet material is 10–160 nm.

[0011] More preferably, the thickness of the sheet material is 20–160 nm.

[0012] More preferably, the thickness of the sheet material is 20–155 nm.

[0013] Preferably, the sheet material includes at least one of TiO2, Ta2O5, SiO2, and BaF2.

[0014] More preferably, the sheet material is SiO2 or TiO2.

[0015] Preferably, the raw material of the varnish layer includes at least one of acrylic acid and polyurethane.

[0016] Preferably, the metal raw material of the frosted metal layer includes at least one of aluminum sheet and steel sheet.

[0017] More preferably, the metal raw material of the frosted metal layer is aluminum sheet.

[0018] Preferably, the roughness of the frosted metal layer is 5 to 50 μm.

[0019] More preferably, the roughness of the frosted metal layer is 5 to 10 μm.

[0020] More preferably, the roughness of the frosted metal layer is 5 μm.

[0021] Preferably, the thickness of the photonic crystal film is 600–2000 nm.

[0022] More preferably, the thickness of the photonic crystal film is 750–2000 nm.

[0023] More preferably, the thickness of the photonic crystal film is 750–1900 nm.

[0024] Preferably, the thickness of the varnish layer is 20–50 μm.

[0025] More preferably, the thickness of the varnish layer is 25–35 μm.

[0026] Preferably, the thickness of the varnish layer is 35 μm.

[0027] Preferably, the thickness of the frosted metal layer is 0.5 to 5 mm.

[0028] More preferably, the thickness of the frosted metal layer is 0.5 to 2 mm.

[0029] More preferably, the thickness of the frosted metal layer is 1 mm.

[0030] A second aspect of the present invention provides a method for preparing a colored coating for automobiles.

[0031] Specifically, it includes the following steps:

[0032] A photonic crystal film is formed by depositing sheet material on the surface of a frosted metal layer using physical vapor deposition. After annealing, a clear coat material is coated on the photonic crystal film to obtain a colored coating for automobiles.

[0033] Preferably, the physical vapor deposition method includes at least one of vacuum evaporation, magnetron sputtering, and arc ion plating.

[0034] More preferably, the physical vapor deposition method is vacuum evaporation.

[0035] Preferably, the annealing temperature is 500–600°C.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] This invention utilizes structural color technology to create rich and dynamic colors through the interference of light with microstructures. This not only provides greater flexibility in color selection but also showcases a dazzling effect that changes with viewing angle, making car exteriors more unique.

[0038] Furthermore, by precisely designing the size and arrangement of the microstructures, more stable colors can be achieved, and these colors are less prone to fading or aging compared to traditional pigments, thus exhibiting better durability. This stability not only extends the coating's lifespan but also reduces subsequent maintenance costs.

[0039] More importantly, the automotive color coating of this invention does not rely on absorbing light to produce color, but rather generates color through the reflection and interference of light, thus significantly reducing solar energy absorption. This helps to lower the temperature of the car's surface, reduce the load on the in-vehicle air conditioning system, and thereby improve the vehicle's energy efficiency, reducing fuel or electricity consumption. These advantages not only improve the car's environmental performance but also increase driving comfort, meeting the comprehensive requirements of modern automotive design for aesthetics, practicality, and environmental protection. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the red coating on a car according to Embodiment 1 of the present invention;

[0041] Figure 2 The reflection and transmission spectra of the red photonic crystal film in the automotive red coating of Embodiment 1 of the present invention are shown in the visible light band.

[0042] Figure 3 The chromaticity value of the red photonic crystal multilayer film of the present invention in the chromaticity diagram;

[0043] Figure 4 This is the reflectance spectrum of the red coating on an automobile in the visible and near-infrared band according to Embodiment 1 of the present invention;

[0044] Figure 5 This is the reflectance spectrum of the blue automotive coating in the visible and near-infrared band according to Embodiment 2 of the present invention.

[0045] Figure 6 This is the reflectance spectrum of the green automotive coating in the visible and near-infrared band of Embodiment 3 of the present invention;

[0046] Figure 7 This is the reflectance spectrum of the purple coating on an automobile in the visible and near-infrared band, as shown in Embodiment 4 of the present invention.

[0047] Figure 8 The images show a comparison of the cooling effect of the red, green and blue colored coatings of Examples 1-3 of the present invention in a summer outdoor environment compared with the commercial blue coating of Comparative Example 1.

[0048] Figure 9 The color range of the colored coating of the present invention in the chromaticity diagram;

[0049] Figure 10 For comparative examples 1-3, reflectance spectra of commercially available colored outer surfaces in the visible and near-infrared bands are shown. Detailed Implementation

[0050] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0051] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0052] Example 1

[0053] A red coating for automobiles and its preparation method.

[0054] The structure of the red automotive coating is as follows: from top to bottom, it consists of a clear coat layer, a photonic crystal film, and a frosted metal layer. The clear coat layer is made of acrylic and has a thickness of 30 μm. The photonic crystal film is a multilayer structure, consisting of alternating layers of TiO2 and SiO2. The thickness of each sheet material, from top to bottom, is 155 / 88 / 50 / 88 / 48 / 84 / 50 / 87 / 50 / 80 / 46 / 66 / 27 / 53 / 40 / 82 / 47 / 84 / 44 / 90 / 48 / 83 / 21 / 50 / 35 / 50 / 48 / 91 / 20 nm. This photonic crystal film is red. The frosted metal layer is an aluminum sheet with a roughness of 5 μm and a thickness of 1 mm. A schematic diagram of the red automotive coating structure in Example 1 is shown below. Figure 1 As shown.

[0055] The preparation method includes the following steps:

[0056] Surface Pretreatment: Before coating, the underlying frosted metal layer needs to be cleaned and prepared to ensure film adhesion and uniformity. Use chemical solvents (alcohol, acetone) or ultrasonic cleaning to remove dust, grease, and other contaminants from the substrate surface. After cleaning, the frosted metal layer needs to be dried, either by air drying, oven drying, or drying in a vacuum environment.

[0057] Coating process: Vacuum evaporation is used. TiO2 and SiO2 are placed in an evaporation source in a high vacuum environment. The materials are evaporated by resistance heating or electron beam heating. The evaporated gas molecules diffuse in the vacuum chamber and are deposited on the surface of the frosted metal layer.

[0058] Post-processing: The frosted metal layer after coating is annealed at high temperature to release the internal stress in the film, improve the structure and adhesion of the film, and finally acrylic acid is coated on the photonic crystal film to obtain the red coating for automobiles.

[0059] Example 2

[0060] A blue coating for automobiles and its preparation method.

[0061] The difference from Example 1 is that the photonic crystal film is a multilayer film structure, which is composed of alternating stacks of TiO2 and SiO2. The thickness of each layer of sheet material is 44 / 56 / 110 / 60 / 120 / 50 / 101 / 70 / 95 / 60 nm from top to bottom; the photonic crystal film is blue.

[0062] Example 3

[0063] A green coating for automobiles and its preparation method.

[0064] The difference from Example 1 is that the photonic crystal film is a multilayer film structure, which is composed of alternating stacks of TiO2 and SiO2. The thickness of each layer of sheet material is 70 / 100 / 140 / 50 / 130 / 108 / 112 / 60 / 90 / 40 / 20 / 130 / 110 / 76 / 46 / 170 nm from top to bottom; the photonic crystal film is green.

[0065] Example 4

[0066] A purple coating for automobiles and its preparation method.

[0067] The difference from Example 1 is that the photonic crystal film is a multilayer film structure, which is composed of alternating stacks of TiO2 and SiO2. The thickness of each sheet material is 30 / 60 / 40 / 70 / 40 / 100 / 30 / 60 / 35 / 51 / 20 / 49 / 127 / 40 / 52 / 15 / 60 / 50 / 140 / 300 / 60 nm from top to bottom; the photonic crystal film is purple.

[0068] Comparative Example 1

[0069] A commercially available blue paint.

[0070] Blue paint, purchased from Nippon Paint.

[0071] Comparative Example 2

[0072] A commercially available red paint.

[0073] Red paint, purchased from Nippon Paint.

[0074] Comparative Example 3

[0075] A commercially available green coating.

[0076] Green paint, purchased from Nippon Paint.

[0077] Figure 2 This is the reflection and transmission spectrum of the red photonic crystal film in the automotive red coating of Embodiment 1 of the present invention in the visible light band. As can be seen from the spectrum, the reflection and transmission spectra are complementary and almost cover the entire visible band. Therefore, part of the light in the entire visible band is reflected from the surface of the red photonic crystal film, and the other part is diffusely reflected back into the field of view by the frosted metal layer at the bottom after passing through the red photonic crystal film. This structural design greatly reduces the absorption of visible light by the structure while generating color.

[0078] Figure 3 This refers to the position of the chromaticity value of the red photonic crystal multilayer film designed in this invention in the chromaticity diagram. The closer to the boundary in the chromaticity diagram, the higher the saturation.

[0079] Figure 4This is the reflectance spectrum of the automotive red coating in the visible and near-infrared band according to Embodiment 1 of the present invention. Light passes through the top clear coat layer and interferes with the multilayer structure, resulting in reflection and transmission. The transmitted light is further reflected by the bottom frosted metal layer. However, due to the multilayer structure and the bottom frosted aluminum sheet layer, cavities are unavoidable. Therefore, light undergoes oscillatory absorption within these cavities, resulting in an oscillatory absorption waveform in the spectrum. Overall, the spectrum of this coating still exhibits high reflectance in the visible and near-infrared band.

[0080] Figure 5 This is the reflectance spectrum of the blue coating on a car in the visible and near-infrared band, according to Embodiment 2 of the present invention. Figure 6 The reflectance spectrum of the green automotive coating in the visible and near-infrared band in Embodiment 3 of this invention. Figure 7 The reflection spectrum of the automotive purple coating in the visible and near-infrared band in Example 4 of this invention shows that the automotive blue coating, automotive green coating and automotive purple coating prepared by this invention can all exhibit high reflectance in the visible and near-infrared band.

[0081] Figure 8 These are comparison charts showing the cooling effect of the red, green, and blue colored coatings of Examples 1-3 of the present invention in a summer outdoor environment compared to the commercial blue coating of Comparative Example 1. Figure 8 (a) is an image of commercial coating applied to the surface of a car, and (b) is an infrared image of the commercial coating, where the color shown in the infrared image is 80°C. Figure 8 Image (c) shows the red, green, and blue coating applied to the surface of a car, and image (d) shows an infrared image of the coating and its surface temperature of 35°C. Ordinary commercial coatings absorb varying degrees of visible light during color formation, resulting in higher temperatures in outdoor environments. In contrast, the colored coating in this invention primarily generates structural colors through the interference of light with a multilayer structure. Light is almost entirely reflected back to the observation side through the multilayer structure and the frosted metal surface at the bottom. Therefore, the colored coating in this invention absorbs very little visible light, thus exhibiting a lower temperature.

[0082] Figure 9 This refers to the color range of the colored coating of this invention in the chromaticity diagram. By designing the structural parameters and dimensions, the achieved color distribution is shown in the chromaticity diagram as a triangle formed by red, green, blue, cyan, blue, and violet. The closer a point is to the boundary on the chromaticity diagram, the higher its saturation. It can be seen that the colors designed in this invention have high saturation characteristics.

[0083] Figure 10For comparative examples 1-3, the reflectance spectra of commercially available colored outer surfaces in the visible and near-infrared bands are shown, using blue, red, and green paints. Their colors are primarily formed by the coloring material absorbing some visible light and reflecting the remaining visible light into the human eye. Therefore, colored paints often have relatively low reflectance in the visible and near-infrared bands. As shown in the figure, such low-reflectance paints absorb most of the visible light energy and exhibit higher temperatures.

[0084] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, any technical solutions obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concept of the present invention and on the existing technology should be within the scope of protection defined by the claims.

Claims

1. A color coating for automobiles, characterized in that, From top to bottom, the layers are: clear varnish layer, photonic crystal film, and frosted metal layer. The photonic crystal film has a multilayer film structure; The multilayer membrane structure is composed of 15 to 30 layers of sheet material stacked alternately; The sheet-like material is SiO2 or TiO2.

2. The automotive color coating according to claim 1, characterized in that, The thickness of the sheet material is 10~160nm.

3. The automotive color coating according to claim 1, characterized in that, The raw material for the varnish layer includes at least one of acrylic acid and polyurethane.

4. The automotive color coating according to claim 1, characterized in that, The metal raw material of the frosted metal layer includes at least one of aluminum sheet and steel sheet.

5. The automotive color coating according to claim 1, characterized in that, The roughness of the frosted metal layer is 5~50μm.

6. The automotive color coating according to claim 1, characterized in that, The thickness of the photonic crystal film is 600~2000 nm.

7. The automotive color coating according to claim 1, characterized in that, The thickness of the varnish layer is 20~50 μm.

8. The automotive color coating according to claim 1, characterized in that, The thickness of the frosted metal layer is 0.5~5mm.

9. The method for preparing the automotive color coating according to any one of claims 1 to 8, characterized in that, Includes the following steps: A photonic crystal film is formed by depositing sheet material on the surface of a frosted metal layer using physical vapor deposition. After annealing, a clear coat material is coated on the photonic crystal film to obtain a colored coating for automobiles.

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