Colored radiation refrigeration paint and colored cooling coating

Abstract

The invention relates to a colored radiation refrigeration coating and a colored cooling coating, the colored radiation refrigeration coating comprises a white prime coating and a colored surface coating which are matched for use, the sunlight reflectivity of a white bottom layer formed by the white prime coating at the wave band of 0.3-2.5 microns is greater than or equal to 95%, and the sunlight reflectivity of the colored surface coating at the wave band of 0.3-2.5 microns is greater than or equal to 95%. The atmospheric window emissivity at the wave band of 8-13 [mu] m is greater than or equal to 95%; the colored surface coating comprises a first filler, yttrium gallium garnet and first resin, the yttrium gallium garnet is doped with chromium, and the mass fraction of the chromium in the yttrium gallium garnet is 5%-15%. A color cooling coating formed by the color radiation refrigeration coating is bright in color, the sunlight reflectivity at the wave band of 0.3-2.5 microns is larger than or equal to 82%, the atmospheric window emissivity at the wave band of 8-13 microns is larger than or equal to 95%, and the color radiation refrigeration coating has an excellent cooling effect.

Description

Technical Field

[0001] The present invention relates to the technical field of radiative cooling, and particularly to a color radiative cooling coating and a color cooling coating. Background Art

[0002] Traditional radiative cooling coatings are mainly pure white. Although white radiative cooling coatings can achieve significant cooling through the synergistic effect of high solar reflectance and mid-infrared radiation, it is difficult to meet the requirements for color diversity in fields such as building facades and sunshade fabrics. Traditional color radiative cooling coatings are prepared by adding pigments to radiative cooling coatings. However, directly blending pigments will cause a significant attenuation of the solar reflectance of color radiative cooling coatings due to the strong absorption characteristics of pigment particles in the near-infrared band (780nm - 2500nm), resulting in insufficient cooling efficiency; on the other hand, color radiative cooling coatings also have problems such as insufficiently bright colors and low color saturation. Summary of the Invention

[0003] Based on this, it is necessary to provide a color radiative cooling coating and a color cooling coating. The color cooling coating formed by the color radiative cooling coating is not only bright in color, but also has a solar reflectance greater than or equal to 82% in the 0.3μm - 2.5μm band and an emissivity greater than or equal to 95% in the 8μm - 13μm atmospheric window, and has excellent cooling effect.

[0004] The present invention provides a color radiative cooling coating, including a white bottom coating and a color top coating used in combination; wherein, the white bottom formed by the white bottom coating has a solar reflectance greater than or equal to 95% in the 0.3μm - 2.5μm band and an emissivity greater than or equal to 96% in the 8μm - 13μm atmospheric window; the color top coating includes a first filler, yttrium gallium garnet, and a first resin, chromium is doped in the yttrium gallium garnet, and the mass fraction of chromium in the yttrium gallium garnet is 5% - 15%.

[0005] In one embodiment, the particle size of the yttrium gallium garnet is 500nm - 50μm.

[0006] In one embodiment, the mass fraction of the yttrium gallium garnet in the color top coating is 20% - 60%.

[0007] In one embodiment, the mass ratio of the yttrium gallium garnet to the first filler is 0.8:1 - 3:1.

[0008] In one embodiment, the color top coating satisfies at least one of the following conditions:

[0009] (1) The first resin is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin or silicone resin;

[0010] (2) The first filler is selected from at least one of aluminum silicate, alumina, zinc oxide, barium sulfate, titanium dioxide or glass beads;

[0011] (3) The mass ratio of the first filler to the first resin is 0.45:1 - 2:1.

[0012] In one embodiment, when used in combination, the mass ratio of the white bottom coating to the colored top coating is 3:1 - 7:1.

[0013] In one embodiment, the white bottom coating includes a second filler and a second resin, wherein the solar reflectance of the second filler in the 0.3μm - 2.5μm band is greater than or equal to 95%, and the emissivity in the 8μm - 13μm atmospheric window is greater than or equal to 96%.

[0014] In one embodiment, the white bottom coating satisfies at least one of the following conditions:

[0015] (1) The second filler is selected from at least one of aluminum silicate, alumina, zinc oxide, barium sulfate, titanium dioxide or glass beads;

[0016] (2) The second resin is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin or silicone resin;

[0017] (3) The mass ratio of the second filler to the second resin is 1:1 - 4:1.

[0018] A colored cooling coating prepared from the colored radiative cooling coating as described above, comprising a white bottom layer and a colored top layer sequentially arranged on the surface of an existing substrate, wherein the colored top layer includes yttrium gallium garnet, and the yttrium gallium garnet is doped with chromium.

[0019] In one embodiment, the thickness of the white bottom layer is 200μm - 1000μm, and the thickness of the colored top layer is 40μm - 60μm.

[0020] In the color radiative cooling coating provided by the present invention, a white bottom coating and a color top coating are used in combination. Among them, the color top coating includes yttrium gallium garnet doped with chromium, and the mass fraction of chromium in yttrium gallium garnet is 5%-15%. It has extremely high fluorescence efficiency, can release the absorbed sunlight in the form of fluorescence, and controls the absorption rate in the visible light band within 18%, effectively reducing the photo-thermal conversion, thereby offsetting part of the problem of the reduction in the sunlight reflectance ratio caused by the color. At the same time, the white bottom formed by the white bottom coating has a sunlight reflectance greater than or equal to 95% in the 0.3μm-2.5μm band and an emissivity greater than or equal to 96% in the 8μm-13μm atmospheric window, significantly improving the thermal radiation efficiency. Thus, the white bottom coating and the color top coating cooperate with each other. The color cooling coating prepared with this color radiative cooling coating not only has bright colors and significantly improved color saturation, but also has a sunlight reflectance greater than or equal to 82% in the 0.3μm-2.5μm band and an emissivity greater than or equal to 95% in the 8μm-13μm atmospheric window, having excellent cooling effects. Detailed Embodiments

[0021] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0022] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] In the first aspect of the present invention, a color radiative cooling coating is provided, which includes a white bottom coating and a color top coating used in combination. Among them, the white bottom formed by the white bottom coating has a solar reflectance greater than or equal to 95% in the wavelength range of 0.3 μm - 2.5 μm, and an emissivity greater than or equal to 96% in the atmospheric window of 8 μm - 13 μm; the color top coating includes a first filler, yttrium gallium garnet, and a first resin. Chromium is doped in the yttrium gallium garnet, and the mass fraction of chromium in the yttrium gallium garnet is 5% - 15%.

[0025] In the color radiative cooling coating provided by the present invention, it includes a white bottom coating and a color top coating used in combination. Among them, the color top coating includes yttrium gallium garnet doped with chromium, and the mass fraction of chromium in the yttrium gallium garnet is 5% - 15%. It has extremely high fluorescence efficiency, can release the absorbed sunlight in the form of fluorescence, and the absorption rate in the visible light band is controlled within 18%, effectively reducing the photo-thermal conversion, thereby offsetting part of the problem of the reduction of the solar reflectance ratio caused by the color.

[0026] At the same time, the white bottom formed by the white bottom coating has a solar reflectance greater than or equal to 95% in the wavelength range of 0.3 μm - 2.5 μm, and an emissivity greater than or equal to 96% in the atmospheric window of 8 μm - 13 μm, significantly improving the thermal radiation efficiency.

[0027] Thus, the white bottom coating and the color top coating cooperate with each other. Using this color radiative cooling coating to prepare a color cooling coating not only has bright colors and significantly improved color saturation, but also has a solar reflectance greater than or equal to 82% in the wavelength range of 0.3 μm - 2.5 μm, and an emissivity greater than or equal to 95% in the atmospheric window of 8 μm - 13 μm, having excellent cooling effect.

[0028] In order to make the white bottom coating and the color top coating cooperate better with each other, when they are used in combination, the mass ratio of the white bottom coating to the color top coating is 3:1 - 7:1, including but not limited to 3:1, 4:1, 5:1, 6:1 or 7:1.

[0029] In the color top coating, the particle size of yttrium gallium garnet is preferably 500 nm - 50 μm, including but not limited to 500 nm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm. In order to make yttrium gallium garnet have more excellent fluorescence efficiency and be better wrapped by the first resin in the color top coating, preferably, the particle size of yttrium gallium garnet is 20 μm - 30 μm.

[0030] In one embodiment, the mass fraction of yttrium gallium garnet in the colored surface coating is 20%-40%; including but not limited to 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38% or 40%.

[0031] In one embodiment, the mass ratio of yttrium gallium garnet to the first filler is 0.8:1 - 3:1, including but not limited to 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3:1.

[0032] In one embodiment, the first resin in the colored surface coating is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin or silicone resin, so that the colored cooling coating made of the colored radiative cooling coating has both bright colors, color saturation and cooling effect.

[0033] In order to further offset the problem of the reduction in the solar reflectance ratio caused by the color of the colored cooling coating, in one embodiment, the solar reflectance of the first filler in the colored surface coating in the 0.3μm - 2.5μm band is greater than or equal to 95%, and the emissivity in the atmospheric window in the 8μm - 13μm band is greater than or equal to 96%. Specifically, the first filler in the colored surface coating is selected from at least one of aluminum silicate, alumina, zinc oxide, barium sulfate, titanium dioxide or glass beads. In one embodiment, the mass ratio of the first filler to the first resin is 0.45:1 - 2:1, including but not limited to 0.45:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1.

[0034] In one embodiment, the white bottom coating includes a second filler and a second resin. Among them, the solar reflectance of the second filler in the 0.3μm - 2.5μm band is greater than or equal to 95%, and the emissivity in the atmospheric window in the 8μm - 13μm band is greater than or equal to 96%. Specifically, the second filler is selected from at least one of aluminum silicate, alumina, zinc oxide, barium sulfate, titanium dioxide or glass beads; so that the white bottom layer has a higher solar reflectance in the 0.3μm - 2.5μm band and a higher emissivity in the atmospheric window in the 8μm - 13μm band. In one embodiment, the mass ratio of the second filler to the second resin is 4:1 - 1:1, including but not limited to 4:1, 3:1, 2:1 or 1:1.

[0035] In one embodiment, the particle size of the second filler is 300 nm - 2000 nm. Within this range, the second filler can produce strong Mie scattering for ultraviolet light, visible light, and near-infrared light, thereby enhancing the solar reflectance of the white bottom layer of the coating in the 0.3 μm - 2.5 μm band, and further enhancing the cooling effect of the color cooling coating.

[0036] In one embodiment, the second resin is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin, or silicone resin.

[0037] In the second aspect of the present invention, there is provided a color cooling coating prepared from the color radiative cooling coating as described above, including a white bottom layer and a color top layer sequentially disposed on the surface of an existing substrate. Among them, the color top layer includes yttrium gallium garnet, and chromium is doped in the yttrium gallium garnet.

[0038] It can be understood that the white bottom layer is made of a white bottom layer coating, and the color top layer is made of a color top layer coating. In one embodiment, the thickness of the white bottom layer is 200 μm - 1000 μm, and the thickness of the color top layer is 40 μm - 60 μm.

[0039] Specifically, the existing substrate includes but is not limited to metal, plastic, rubber, concrete, cement, asphalt, paper, textile, wood, tile, glass, or organic synthetic material.

[0040] The color cooling coating provided by the present invention not only has bright colors and high color saturation, but also has a solar reflectance greater than or equal to 82% in the 0.3 μm - 2.5 μm band, and an emissivity greater than or equal to 95% in the atmospheric window of 8 μm - 13 μm, having excellent cooling effect.

[0041] The following further describes the present invention in detail with specific examples and comparative examples. It can be understood that the instruments and raw materials used in the following examples are relatively specific, and in other specific examples, this may not be limited.

[0042] Example 1

[0043] The color radiative cooling coating of this example includes a white bottom layer coating and a color top layer coating.

[0044] The color top layer coating is composed of the first filler alumina, yttrium gallium garnet, and the first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of the yttrium gallium garnet is 1 μm - 10 μm, the average particle size is 5.5 μm, the mass fraction of the yttrium gallium garnet is 38%, chromium is doped in the yttrium gallium garnet, and the mass fraction of chromium in the yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0045] The white bottom coating is composed of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The white bottom formed by the white bottom coating has a solar reflectance of 95.7% in the wavelength range of 0.3μm - 2.5μm, and an emissivity of 97% in the atmospheric window of 8μm - 13μm.

[0046] When used in combination, the mass ratio of the white bottom coating to the colored top coating is 10:3. First, a white bottom with a thickness of 200μm is formed on the surface of the existing matrix aluminum bottom plate using the white bottom coating, and then a colored top layer with a thickness of 60μm is formed on the surface of the white bottom using the colored top coating to form a colored cooling coating.

[0047] Example 2

[0048] Example 2 is carried out with reference to Example 1, the difference being that the existing matrix is replaced with a cement bottom plate.

[0049] The colored radiative cooling coating of this example includes a white bottom coating and a colored top coating.

[0050] The colored top coating is composed of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 38%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0051] The white bottom coating is composed of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The white bottom formed by the white bottom coating has a solar reflectance of 95.7% in the wavelength range of 0.3μm - 2.5μm, and an emissivity of 97% in the atmospheric window of 8μm - 13μm.

[0052] When used in combination, the mass ratio of the white bottom coating to the colored top coating is 10:3. First, a white bottom with a thickness of 200μm is formed on the surface of the existing matrix cement bottom plate using the white bottom coating, and then a colored top layer with a thickness of 60μm is formed on the surface of the white bottom using the colored top coating to form a colored cooling coating.

[0053] Comparative Example 1

[0054] Comparative Example 1 is carried out with reference to Example 1, the difference being that the mass fraction of chromium in yttrium gallium garnet is 20%.

[0055] The colored radiative cooling coating of this example includes a white bottom coating and a colored top coating.

[0056] The colored surface coating consists of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 38%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 20%, and the mass fraction of the first resin is 42%.

[0057] The white bottom coating consists of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The solar reflectance of the white bottom formed by the white bottom coating in the 0.3μm - 2.5μm band is 95.7%, and the emissivity in the 8μm - 13μm atmospheric window band is 97%.

[0058] When used in combination, the mass ratio of the white bottom coating to the colored surface coating is 10:3. First, use the white bottom coating to form a white bottom with a thickness of 200μm on the surface of the existing substrate aluminum bottom plate, and then use the colored surface coating to form a colored surface with a thickness of 60μm on the surface of the white bottom to form a colored cooling coating.

[0059] Comparative Example 2

[0060] Comparative Example 2 was carried out with reference to Example 1, the difference being that the mass fraction of chromium in yttrium gallium garnet was 40%.

[0061] The colored radiative cooling coating of this example includes a white bottom coating and a colored surface coating.

[0062] The colored surface coating consists of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 38%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 40%, and the mass fraction of the first resin is 42%.

[0063] The white bottom coating consists of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The solar reflectance of the white bottom formed by the white bottom coating in the 0.3μm - 2.5μm band is 95.7%, and the emissivity in the 8μm - 13μm atmospheric window band is 97%.

[0064] When used in combination, the mass ratio of the white bottom coating to the colored surface coating is 10:3. First, use the white bottom coating to form a white bottom with a thickness of 200μm on the surface of the existing substrate aluminum bottom plate, and then use the colored surface coating to form a colored surface with a thickness of 60μm on the surface of the white bottom to form a colored cooling coating.

[0065] Comparative Example 3

[0066] Comparative Example 3 was carried out with reference to Example 1, except that the mass fraction of chromium in yttrium gallium garnet was 4%.

[0067] The color radiation cooling coating of this example includes a white bottom coating and a color top coating.

[0068] The color top coating is composed of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 38%, yttrium gallium garnet is doped with chromium, and the mass fraction of chromium in yttrium gallium garnet is 4%, and the mass fraction of the first resin is 42%.

[0069] The white bottom coating is composed of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%, the solar reflectance of the white bottom formed by the white bottom coating in the 0.3μm - 2.5μm band is 95.7%, and the emissivity in the 8μm - 13μm atmospheric window band is 97%.

[0070] When used in combination, the mass ratio of the white bottom coating to the color top coating is 10:3. First, a white bottom with a thickness of 200μm is formed on the surface of the existing substrate aluminum bottom plate with the white bottom coating, and then a color top layer with a thickness of 60μm is formed on the surface of the white bottom with the color top coating to form a color cooling coating.

[0071] Comparative Example 4

[0072] Comparative Example 4 was carried out with reference to Example 1, except that the mass fraction of chromium in yttrium gallium garnet was 16%.

[0073] The color radiation cooling coating of this example includes a white bottom coating and a color top coating.

[0074] The color top coating is composed of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 38%, yttrium gallium garnet is doped with chromium, and the mass fraction of chromium in yttrium gallium garnet is 16%, and the mass fraction of the first resin is 42%.

[0075] The white base coat is composed of a second filler, alumina, and a second resin, acrylic resin. Among them, the mass fraction of the second filler, alumina, is 80%. The white base formed by the white base coat has a solar reflectance of 95.7% in the 0.3μm - 2.5μm band, and an emissivity of 97% in the 8μm - 13μm atmospheric window band.

[0076] When used in combination, the mass ratio of the white base coat to the colored top coat is 10:3. First, a white base with a thickness of 200μm is formed on the surface of the existing substrate aluminum bottom plate using the white base coat, and then a colored top coat with a thickness of 60μm is formed on the surface of the white base to form a colored cooling coating.

[0077] Comparative Example 5

[0078] Comparative Example 5 was carried out with reference to Example 1, except that the white base coat had a solar reflectance of 90% in the 0.3μm - 2.5μm band and an emissivity of 0.95% in the 8μm - 13μm atmospheric window band.

[0079] Test Example 1

[0080] The solar reflectance in the 0.3μm - 2.5μm band, the reflectance of near-infrared rays, the reflectance of ultraviolet rays, the emissivity in the 8μm - 13μm atmospheric window band, and the color performance of the colored cooling coatings provided by Test Examples 1 - 2 and Comparative Examples 1 - 5 were tested as follows, and the test results are shown in Tables 1 - 2.

[0081] The solar reflectance in the 0.3μm - 2.5μm band, the reflectance of near-infrared rays, the reflectance of ultraviolet rays, the emissivity in the 8μm - 13μm atmospheric window band: Tested with reference to 《JGJ / T287 - 2014》, 《T / ZZB 2304 - 2021》.

[0082] Color performance: Tested with reference to 《ISO7724 / 2 - 1984 Paints and varnishes - Color measurement - Part 2: Color measurement》.

[0083] Table 1

[0084]

[0085] Table 2

[0086]

[0087]

[0088] Example 3

[0089] Example 3 was carried out with reference to Example 1, except that in the colored surface coating, the particle size of yttrium gallium garnet was 500 nm - 1 μm, and the average particle size was 0.75 μm.

[0090] The colored radiative cooling coating of this example includes a white bottom coating and a colored surface coating.

[0091] The colored surface coating is composed of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 500 nm - 1 μm, the average particle size is 0.75 μm, the mass fraction of yttrium gallium garnet is 38%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0092] The white bottom coating is composed of a second filler alumina and a second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The solar reflectance of the white bottom formed by the white bottom coating in the wavelength range of 0.3 μm - 2.5 μm is 95.7%, and the emissivity in the atmospheric window of 8 μm - 13 μm is 97%.

[0093] When used in combination, the mass ratio of the white bottom coating to the colored surface coating is 10:3. First, a white bottom with a thickness of 200 μm is formed on the surface of the existing substrate aluminum bottom plate with the white bottom coating, and then a colored surface with a thickness of 60 μm is formed on the surface of the white bottom with the colored surface coating to form a colored cooling coating.

[0094] Example 4

[0095] Example 4 was carried out with reference to Example 1, except that in the colored surface coating, the particle size of yttrium gallium garnet was 20 μm - 40 μm, and the average particle size was 30 μm.

[0096] The colored radiative cooling coating of this example includes a white bottom coating and a colored surface coating.

[0097] The colored surface coating is composed of a first filler alumina, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 20%, the particle size of yttrium gallium garnet is 20 μm - 40 μm, the average particle size is 30 μm, the mass fraction of yttrium gallium garnet is 38%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0098] The white bottom coating is composed of the second filler alumina and the second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The white bottom formed by the white bottom coating has a solar reflectance of 95.7% in the 0.3μm - 2.5μm band and an emissivity of 97% in the 8μm - 13μm atmospheric window.

[0099] When used in combination, the mass ratio of the white bottom coating to the colored top coating is 10:3. First, the white bottom coating is used to form a white bottom with a thickness of 200μm on the surface of the existing substrate aluminum bottom plate, and then the colored top coating is used to form a colored top layer with a thickness of 60μm on the surface of the white bottom to form a colored cooling coating.

[0100] Example 5

[0101] Example 5 is carried out with reference to Example 1. The difference is that in the colored top coating, the mass ratio of yttrium gallium garnet to the first filler is 1:1.

[0102] The colored radiative cooling coating of this example includes a white bottom coating and a colored top coating.

[0103] The colored top coating is composed of the first filler alumina, yttrium gallium garnet, and the first resin acrylic resin. Among them, the mass fraction of the first filler is 29%, the particle size of yttrium gallium garnet is 1μm - 10μm, the average particle size is 5.5μm, the mass fraction of yttrium gallium garnet is 29%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0104] The white bottom coating is composed of the second filler alumina and the second resin acrylic resin. Among them, the mass fraction of the second filler alumina is 80%. The white bottom formed by the white bottom coating has a solar reflectance of 95.7% in the 0.3μm - 2.5μm band and an emissivity of 97% in the 8μm - 13μm atmospheric window.

[0105] When used in combination, the mass ratio of the white bottom coating to the colored top coating is 10:3. First, the white bottom coating is used to form a white bottom with a thickness of 200μm on the surface of the existing substrate aluminum bottom plate, and then the colored top coating is used to form a colored top layer with a thickness of 60μm on the surface of the white bottom to form a colored cooling coating.

[0106] Example 6

[0107] Example 6 is carried out with reference to Example 1. The difference is that in the colored top coating, the mass ratio of yttrium gallium garnet to the first filler is 3:1.

[0108] The colored radiative cooling coating of this example includes a white bottom coating and a colored top coating.

[0109] The colored surface coating is composed of a first filler aluminum oxide, yttrium gallium garnet, and a first resin acrylic resin. Among them, the mass fraction of the first filler is 14.5%, the particle size of yttrium gallium garnet is 1 μm - 10 μm, the average particle size is 5.5 μm, the mass fraction of yttrium gallium garnet is 43.5%, chromium is doped in yttrium gallium garnet, and the mass fraction of chromium in yttrium gallium garnet is 8%, and the mass fraction of the first resin is 42%.

[0110] The white bottom coating is composed of a second filler aluminum oxide and a second resin acrylic resin. Among them, the mass fraction of the second filler aluminum oxide is 80%, the solar reflectance of the white bottom formed by the white bottom coating in the 0.3 μm - 2.5 μm band is 95.7%, and the emissivity in the 8 μm - 13 μm atmospheric window is 97%.

[0111] When used in combination, the mass ratio of the white bottom coating to the colored surface coating is 10:3. First, a white bottom with a thickness of 200 μm is formed on the surface of the existing substrate aluminum bottom plate with the white bottom coating, and then a colored surface with a thickness of 60 μm is formed on the surface of the white bottom with the colored surface coating to form a colored cooling coating.

[0112] Test Example 2

[0113] Test Example 2 was carried out with reference to Test Example 1. The solar reflectance, near-infrared reflectance, ultraviolet reflectance, emissivity in the 8 μm - 13 μm atmospheric window, and color performance of the colored cooling coatings provided in Test Examples 3 - 6 were tested. The test results are shown in Table 3.

[0114] Table 3

[0115]

[0116] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0117] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A color radiation cooling paint, characterized in that: It comprises a white base coating and a colored surface coating used in combination; wherein the white base formed by the white base coating has a sunlight reflectivity greater than or equal to 95% in the 0.3μm-2.5μm band, and an atmospheric window emissivity greater than or equal to 96% in the 8μm-13μm band; the colored surface coating comprises a first filler, yttrium gallium garnet and a first resin, the yttrium gallium garnet is doped with chromium, and the mass fraction of chromium in the yttrium gallium garnet is 5%-15%.

2. The color radiation cooling paint according to claim 1, characterized in that: The particle size of the yttrium gallium garnet is 500nm-50μm.

3. The color radiation cooling paint according to claim 1, characterized in that: The mass fraction of the yttrium gallium garnet in the colored surface coating is 20%-60%.

4. The color radiation cooling paint according to claim 1, characterized in that: The mass ratio of the yttrium gallium garnet to the first filler is 0.8:1-3:

1.

5. The color radiation cooling paint according to claim 1, characterized in that: The colored surface coating satisfies at least one of the following conditions: (1) the first resin is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin or silicone resin; (2) the first filler is selected from at least one of aluminum silicate, aluminum oxide, zinc oxide, barium sulfate, titanium dioxide or glass beads; (3) The mass ratio of the first filler to the first resin is 0.45:1-2:

1.

6. The color radiation cooling paint according to any one of claims 1 to 5, characterized in that: When used together, the mass ratio of the white base coating to the colored top coating is 3:1-7:

1.

7. The color radiation cooling paint according to any one of claims 1 to 5, characterized in that: The white primer includes a second filler and a second resin, wherein the second filler has a solar reflectivity greater than or equal to 95% in the 0.3 μm-2.5 μm band and an atmospheric window emissivity greater than or equal to 96% in the 8 μm-13 μm band.

8. The color radiation cooling paint according to claim 7, characterized in that: The white primer meets at least one of the following conditions: (1) the second filler is selected from at least one of aluminum silicate, aluminum oxide, zinc oxide, barium sulfate, titanium dioxide or glass beads; (2) the second resin is selected from at least one of epoxy resin, polyester, polyurethane, acrylic resin or silicone resin; (3) The mass ratio of the second filler to the second resin is 1:1-4:

1.

9. A colored cooling coating prepared from the colored radiation cooling coating according to any one of claims 1 to 8, characterized in that: It comprises a white bottom layer and a colored top layer which are sequentially arranged on the surface of an existing substrate, wherein the colored top layer comprises yttrium gallium garnet, and the yttrium gallium garnet is doped with chromium.

10. The colored cooling coating according to claim 9, characterized in that: The thickness of the white bottom layer is 200 μm-1000 μm, and the thickness of the colored surface layer is 40 μm-60 μm.

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