A high spectral selectivity radiative cooling automobile sunroof film and preparation method thereof

Abstract

The present application discloses a highly spectrally selective radiation cooling automobile sunroof film and a preparation method thereof, which belongs to the fields of energy conservation and environmental protection and new materials, and comprises a release film layer, an adhesive layer, a first polymer substrate layer, a solar heat reflection layer, a high-transmittance radiation cooling layer, and a second polymer substrate layer which are sequentially stacked; the solar reflection layer comprises a ceramic anti-reflection layer and a metal reflection layer which are alternately stacked in sequence; the number of layers of the ceramic anti-reflection layer is one more than the number of layers of the metal reflection layer, and the refractive index of the ceramic anti-reflection layer is greater than 2. The product film is thin and transparent in color. Without affecting the color of the car itself, it has a visible light band transmittance greater than 75%, a near-infrared light reflectance greater than 70%, an 8-13um atmospheric window emissivity greater than 97%, and a refractive index greater than 150W / m 2 Ultra-high radiation cooling power. This radiation cooling car sunroof film is suitable for long-term use of car sunroofs or skylights.

Description

Technical Field

[0001] The present application relates to a highly spectrally selective radiation cooling automobile sunroof film and a preparation method thereof, and belongs to the fields of energy conservation and environmental protection and new materials. Background Art

[0002] In the summer, the interior of a car is hot, and about 40% of the heat is transmitted through the roof. For cars with sunroofs, this proportion exceeds 50%. In order to obtain better cooling and heat insulation effects, conventional car films mostly use the method of increasing the reflectivity of sunlight and using opaque films to attach to the top of the car. Although this method can achieve better cooling and heat insulation effects, it will change the color of the roof and block the light transmission effect of the sunroof. Therefore, a radiant cooling film with high visible light transmittance that can be attached to the top sunroof of a car has a wide and urgent demand in social life.

[0003] Radiative cooling technology modifies the micro-nano structure on the surface of the material to give it a high reflectivity in the solar band (0.3-2.5µm) to avoid heating up under sunlight. At the same time, it has a high-intensity atmospheric window (8-13µm) emissivity, so that its heat can penetrate the atmosphere and be conducted to outer space through infrared thermal radiation, thereby achieving a radiative cooling effect. Summary of the invention

[0004] According to one aspect of the present application, a highly spectrally selective radiant cooling automobile sunroof film is provided, which solves the problem in the prior art that automobile thermal insulation films can reduce temperature and insulate to a certain extent but will change the color and light transmission effect of the roof through material layer structure design.

[0005] This application adopts the following technical solutions:

[0006] A highly spectrally selective radiation cooling automobile sunroof film, comprising a release film layer, an adhesive layer, a first high molecular polymer substrate layer, a solar heat reflection layer, a high-transmittance radiation cooling layer, and a second high molecular polymer substrate layer which are sequentially stacked;

[0007] The solar reflection layer comprises a ceramic anti-reflection layer and a metal reflection layer which are alternately stacked in sequence;

[0008] The number of layers of the ceramic anti-reflection layer is one more than the number of layers of the metal reflective layer;

[0009] The refractive index of the ceramic anti-reflection layer is greater than 2.

[0010] The function of the ceramic anti-reflection layer is to reduce the reflected light on the surface of the material and increase the transmitted light, that is, to reduce the reflectivity of the entire radiation cooling film and increase the transmittance of the transmitted light of the entire radiation cooling film.

[0011] Optionally, the number of layers of the metal reflective layer is 1-3.

[0012] Optionally, the thickness of the metal reflective layer is 10-25 nm.

[0013] In the solar reflection layer, the material of the metal reflection layer is selected from at least one of Al, Ag, Ni, and Cd.

[0014] Optionally, when the reflective layer has more than two materials, they are metal alloys.

[0015] Optionally, the thickness of the solar reflection layer is 50-500 nm.

[0016] Optionally, the thickness of the solar reflection layer is selected from any value of 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, or any range therebetween.

[0017] In the solar reflection layer, the material of the ceramic anti-reflection layer is selected from at least one of TiO2, Nb2O5, Si3N4, and CeO2.

[0018] Optionally, the thickness of the ceramic anti-reflection layer is 20-110 nm.

[0019] Optionally, the thickness of the ceramic anti-reflection layer is 20-30 nm.

[0020] Optionally, the high radiation transmittance refrigeration layer is a polymer resin layer with thermal radiation functional ceramic particles uniformly dispersed inside.

[0021] The thermal radiation functional ceramic particles are selected from at least one of TiO2, Al2O3, SiO2, Si3N4, and BaSO4.

[0022] The particle size of the thermal radiation functional ceramic particles is less than 100 nm.

[0023] Optionally, the particle size of the thermal radiation functional ceramic particles is selected from any value of 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any range therebetween.

[0024] The thickness of the high radiation transmittance refrigeration layer is 1-20 μm.

[0025] Optionally, the thickness of the high radiation transmittance cooling layer is selected from any value of 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, or any range therebetween.

[0026] Optionally, a scratch-resistant self-repairing protective layer is further provided on the side of the high radiation transmittance refrigeration layer facing away from the second high molecular polymer substrate layer.

[0027] The scratch-resistant self-repairing protective layer uses TPU-based self-repairing thermosetting coating produced by Shanghai Huzheng Nanotechnology Co., Ltd., with the product code PRR-TPU.

[0028] The thickness of the scratch-resistant self-repairing protective layer is 1-10 μm.

[0029] Optionally, the thickness of the scratch-resistant self-repairing protective layer is selected from any value of 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, or any range of values ​​therebetween.

[0030] Optionally, the release film layer is a PET film with a thickness of 50-100 μm.

[0031] Optionally, the thickness of the release film layer is selected from any value of 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, or any range therebetween.

[0032] The first high molecular polymer substrate layer and the second high molecular polymer substrate layer are independently TPU films with a thickness of 50 to 100 μm.

[0033] Optionally, the thickness of the first polymer substrate layer and the second polymer substrate layer are independently selected from any value of 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, or any range therebetween.

[0034] The adhesive layer is a pressure-sensitive adhesive with a thickness of 1 to 5 μm.

[0035] Optionally, the thickness of the adhesive layer is selected from any value of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or any range therebetween.

[0036] Optionally, the highly spectrally selective radiative cooling automobile sunroof film includes the following technical features:

[0037] Visible light transmittance greater than 75%; and / or,

[0038] Near infrared light reflectivity greater than 70%; and / or,

[0039] 8-13um atmospheric window emissivity greater than 97%; and / or,

[0040] Radiant cooling power greater than 150W / m 2 .

[0041] According to another aspect of the present application, a method for preparing the above-mentioned highly spectrally selective radiative cooling automobile sunroof film is also provided, characterized in that it comprises the following steps:

[0042] S1, after coating a pressure-sensitive adhesive on one side of the first high molecular polymer substrate layer, compounding a release film with the first high molecular polymer substrate layer;

[0043] S2, sputtering to form a solar heat reflecting layer on a side of the first high molecular polymer substrate layer away from the pressure-sensitive adhesive layer;

[0044] S3, coating a polymer resin containing heat radiation functional ceramic particles on the side of the solar heat reflection layer away from the first polymer substrate layer to form a high radiation transmittance cooling layer;

[0045] S4. Laminating a second high molecular polymer substrate layer on the side of the high radiation transmittance cooling layer away from the solar reflection layer.

[0046] Optionally, after step S4, the method further includes laminating a scratch-resistant self-repairing protective layer on a side of the second high molecular polymer substrate layer away from the high radiation transmittance refrigeration layer.

[0047] Optionally, in step S2, the sputtering to form the solar heat reflection layer includes first sputtering to form a first ceramic anti-reflection layer, and then alternately sputtering a metal reflection layer and a ceramic anti-reflection layer on the first ceramic anti-reflection layer.

[0048] Optionally, the sputtering conditions include: a temperature of -15°C to 25°C, a mixed gas of oxygen and argon with a volume ratio of 10 to 100:1 is introduced into the chamber, and a sputtering vacuum degree of 10 -6 Torr, the coating stable pressure is 10 -3 Torr;

[0049] Optionally, the sputtering method of the ceramic anti-reflection layer is dual-rotating cathode, medium-frequency reactive magnetron sputtering, and the power of the dual-rotating cathode, medium-frequency reactive magnetron sputtering is 20-50Kw;

[0050] In the present application, the preparation of a high refractive index ceramic antireflection film is achieved by controlling the process and conditions of magnetron sputtering.

[0051] Optionally, the sputtering method of the metal reflective layer is single rotating cathode, DC reaction magnetron sputtering, and the power of the single rotating cathode, DC reaction magnetron sputtering is 2~5Kw.

[0052] The above-mentioned high-spectral selective radiation cooling car sunroof film can be attached to the top sunroof of the car to improve the heat insulation performance of the car and avoid a large amount of heat being transferred to the interior of the car under sunlight exposure.

[0053] Thermoplastic polyurethane elastomer (TPU) is a type of elastomer that can be plasticized by heating and dissolved by solvents. It has excellent comprehensive properties such as high strength, high toughness, wear resistance, oil resistance, and good processing performance. Based on the characteristics of TPU, the above-mentioned high spectral selectivity radiation cooling car sunroof film can be prepared on the surface of the substrate by magnetron sputtering.

[0054] The beneficial effects of this application include:

[0055] The high-spectral selective radiation cooling car sunroof film provided by the present application is thin and transparent, and can be attached to any position on the car roof. Without affecting the color of the car itself, it has a visible light band transmittance greater than 75%, a near-infrared light reflectivity greater than 70%, an 8-13um atmospheric window emissivity greater than 97%, and a thermal conductivity greater than 150W / m 2 The ultra-high radiation cooling power of the product is good in flexibility and shrinkage, and it is not easy to wrinkle or bubble when attached to the car. In addition, the high-spectral selective radiation cooling car sunroof film product provided by the application has a simple production process, can better control the sputtering effect of the material, and the finished product has good bending, scratch resistance and outdoor weather resistance, and has both cooling and protection functions, which is very suitable for long-term use of car sunroofs or awnings. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the cross-sectional structure of the highly spectrally selective radiative cooling automobile sunroof film of this application.

[0057] Figure 2 This is a schematic diagram of the cross-sectional structure of the solar heat reflection layer in the highly spectrally selective radiative cooling automobile sunroof film of this application.

[0058] Figure 3 Spectral diagram of the highly spectrally selective radiative cooling car sunroof film for this application.

[0059] Figure ID

[0060] 1. Release film layer; 2. Adhesive layer; 3. First polymer substrate layer; 4. Solar heat reflection layer; 5. High-transmittance radiation cooling layer; 6. Second polymer substrate layer; 7. Scratch-resistant self-repairing protective layer; 8. Metal reflection layer; 9. Ceramic anti-reflection layer. DETAILED DESCRIPTION

[0061] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0062] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0063] Unless otherwise specified, the technical means used in the embodiments of the present invention are conventional means well known to those skilled in the art.

[0064] The atmospheric window emissivity is tested using a Fourier transform infrared spectrometer with an integrating sphere. The performance of the equipment should meet the following requirements: the wavelength range of the infrared spectrometer should not be less than 3μm~25μm; the inner diameter of the integrating sphere should not be less than 60mm, and the inner wall should be made of highly reflective material; the standard plate should be a polytetrafluoroethylene plate or a gold mirror (should be qualified by the metrology department and within the validity period of the appraisal). The atmospheric window emissivity detection range is 0.05~0.99, and the detection accuracy should be 0.01 or higher.

[0065] The atmospheric window emissivity refers to the provisions of 4.3 of JGJ / T287-2014, and the result of the atmospheric transmission window band (8~13)μm is taken and calculated according to formula (1), where G λ The selection of is shown in Table A.1 in Appendix A of JGJ / T287-2014 standard. The atmospheric window (8-13) μm emissivity of three samples should be tested, and the arithmetic mean value should be taken as the final result.

[0066] Formula (1).

[0067] The test method for solar transmittance refers to the provisions of 5.1.1 of GB / T 2680-2021, taking the results of the visible light band (380nm~780nm) and calculating according to formula (2), using D λ V( λ )Δ λ The values ​​of the corresponding bands can be found in Table 1 of the GB / T 2680-2021 standard. The solar transmittance of three tests should be tested and the arithmetic mean should be taken as the final result.

[0068] Formula (2).

[0069] According to one implementation of the present application, Figure 1 The preparation process of the highly spectrally selective radiative cooling automobile sunroof film of the structure shown includes:

[0070] 1. Provide a release film layer (1) with a thickness of 50-100 μm and made of PET film; to ensure that the subsequent processes proceed normally, the release film layer (1) must not deform under a tensile force of 200-400 N.

[0071] 2. Provide a first substrate layer (3) with a thickness of 50-100 μm and made of a TPU film; apply an adhesive layer (2) with a pressure-sensitive adhesive material and a thickness of 1-5 μm on its surface, and laminate a release film layer (1).

[0072] 3. Depositing a solar heat reflection layer (4) on the first substrate layer (3) by magnetron sputtering; the solar heat reflection layer (4) is formed by cross-stacked 2 to 4 ceramic anti-reflection layers and 1 to 3 metal reflection layers; the thickness of each ceramic anti-reflection layer is 20 to 110 nm, and the material is one or more mixtures of TiO2, Nb2O5, Si3N4, CeO2, etc., and the refractive index is greater than 2; the thickness of each metal reflection layer is 10 to 25 nm, and the material is one pure metal or multiple metal alloys such as aluminum, silver, nickel, cadmium, etc. The sputtering method of each ceramic anti-reflection layer is double rotating cathode, medium frequency reaction magnetron sputtering, and the sputtering method of each metal reflection layer is single rotating cathode, DC reaction magnetron sputtering. After sputtering, the thickness of the solar heat reflection layer (4) is controlled in the range of 50 to 500 nm.

[0073] 4. A high-radiation-transmittance cooling layer (5) is coated on the solar heat reflection layer (4) by means of a roll-to-roll coating and bonding line, wherein the high-radiation-transmittance cooling layer (5) has a thickness of 1-20 μm and is made of functional mid- and far-infrared radiation ceramic particles (one or more of titanium oxide, aluminum oxide, silicon oxide, silicon nitride, and barium sulfate, with a size less than 100 nm).

[0074] 5. A second substrate layer (6) is laminated on the high radiation transmittance cooling layer (5). The second substrate layer has a thickness of 50-100 um and is made of a TPU film.

[0075] 6. A scratch-resistant self-repairing protective layer (7) is coated on the second substrate layer (6) by means of a winding coating and bonding line, wherein the scratch-resistant self-repairing protective layer (7) has a thickness of 1 to 10 μm and is made of scratch-resistant polyurethane and a self-repairing coating. The scratch-resistant self-repairing protective layer (7) after coating is baked and cured at a temperature of >100° C., with a baking rate of about 20 to 30 m / min.

[0076] During magnetron sputtering deposition coating, the temperature in all chambers is constant, ranging from -15°C to 25°C.

[0077] During magnetron sputtering deposition, a mixed gas of oxygen and argon with a volume ratio of 100:1 to 10:1 is introduced into the chamber, and the sputtering vacuum is set to 10 -6 Torr, the coating stable pressure is 10 -3 Torr; the power of double rotating cathode and medium frequency reactive magnetron sputtering is 20Kw~50Kw; the power of single rotating cathode and DC reactive magnetron sputtering is 2Kw~5Kw.

[0078] Example 1

[0079] 1. Provide a release film layer (1) with a thickness of 60 μm and made of PET film; to ensure that the subsequent processes proceed normally, the release film layer (1) must not deform under a tensile force of 200 to 400 N.

[0080] 2. Provide a first high molecular polymer substrate layer (3) with a thickness of 70 μm and made of a TPU film; apply an adhesive layer (2) with a pressure-sensitive adhesive material and a thickness of 2 μm on its surface, and compound a release film layer (1).

[0081] 3. Depositing a solar heat reflection layer (4) on the first high molecular polymer substrate layer (3) by magnetron sputtering; Figure 2 As shown in the structure, the solar heat reflection layer (4) is formed by cross-stacked 2 ceramic anti-reflection layers and 1 metal reflection layer; each ceramic anti-reflection layer has a thickness of 25nm and is made of TiO2, whose refractive index is greater than 2; each metal reflection layer has a thickness of 15nm and is made of silver. The sputtering method of each ceramic anti-reflection layer is double rotating cathode, medium frequency reactive magnetron sputtering, and the sputtering method of each metal reflection layer is single rotating cathode, DC reactive magnetron sputtering. After sputtering, the thickness of the solar heat reflection layer (4) is controlled within the range of 65nm.

[0082] 4. A high-radiation-transmittance cooling layer (5) is coated on the solar heat reflection layer (4) by means of a winding coating and bonding line. The high-radiation-transmittance cooling layer (5) has a thickness of 5 μm and is made of functional mid- and far-infrared radiation ceramic particles (silicon oxide, with a size of 5 nm).

[0083] 5. A second high molecular polymer substrate layer (6) is laminated on the high radiation transmittance refrigeration layer (5). The second high molecular polymer substrate layer has a thickness of 70 um and is made of a TPU film.

[0084] 6. A scratch-resistant self-repairing protective layer (7) is coated on the second polymer substrate layer (6) by means of a winding coating and bonding line. The scratch-resistant self-repairing protective layer (7) has a thickness of 8 μm and is made of a TPU substrate self-repairing thermosetting coating (product code PRR-TPU) produced by Shanghai Huzheng Nanotechnology Co., Ltd. The scratch-resistant self-repairing protective layer (7) is baked and cured at a temperature of 100° C. at a baking rate of about 30 m / min to obtain a highly spectrally selective radiant cooling automotive sunroof film.

[0085] During magnetron sputtering deposition, the temperature in all chambers is constant within a range of 25°C.

[0086] During magnetron sputtering deposition, a mixture of oxygen and argon with a volume ratio of 40:1 was introduced into the chamber, and the sputtering vacuum was set to 10 -6 Torr, the coating stable pressure is 10 -3 Torr; dual rotating cathode, medium frequency reactive magnetron sputtering power is 30Kw; single rotating cathode, DC reactive magnetron sputtering power is 3Kw.

[0087] Test Example 1

[0088] The optical properties of the high spectral selective radiation cooling automobile sunroof film prepared were tested and calculated by a spectrophotometer. The test results of Example 1 are as follows: Figure 3 As shown, the product has a visible light transmittance of >75%, a near-infrared light reflectivity of >70%, an 8-13um atmospheric window emissivity of >97% and a power rating of >150W / m 2 Ultra-high radiative cooling power.

[0089] Test Example 2

[0090] In order to verify the application effect of the product of this application, a comparative test was conducted as follows: three cars of the same model and color were selected, and were denoted as A, B, and C respectively. The front and rear windshields and side windows of the three cars were not covered with film. The difference was that the sunroof of vehicle A was covered with the high-spectral selective radiation cooling car sunroof film in Example 1 of this application, the sunroof of vehicle B was covered with commercial Feiteng Leopard TPU Ice Blue Sky Window Ice Armor, and the sunroof of vehicle C was not covered with film.

[0091] Temperature probe points were arranged for the three car pairs: the center point of the outer surface of the car sunroof (hereinafter referred to as position 1), the middle position of the car's internal console (hereinafter referred to as position 2), and a position 60 cm above the center of the car's internal console at about head height (hereinafter referred to as position 3). Temperature comparison was carried out in the same time period. The results are shown in Table 1.

[0092] The following conclusions can be drawn from Table 1:

[0093] 1) The temperature of the sunroof using high spectral selective radiative cooling car sunroof film is reduced by >5 ℃ compared with the sunroof without film, and by >10 ℃ compared with the commercial sunroof ice armor.

[0094] 2) The temperature inside the car using the highly spectrally selective radiative cooling car sunroof film is reduced by >15℃ compared to the car without film, and by >10℃ compared to the commercial sunroof ice armor.

[0095] 3) Highly spectrally selective radiant cooling car sunroof films can reduce the temperature of the sunroof glass and the temperature inside the car at the same time, while commercial sunroof ice armor will heat the sunroof glass and limit the cooling effect inside the car.

[0096] By comparison, it can be found that the high spectral selectivity radiant cooling automobile sunroof film provided by the present application has good cooling and heat insulation effects.

[0097] Table 1 Temperature comparison

[0098]

[0099] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A highly spectrally selective radiative cooling automotive sunroof film, characterized in that: It includes a release film layer, an adhesive layer, a first high molecular polymer substrate layer, a solar heat reflection layer, a high radiation transmission refrigeration layer, and a second high molecular polymer substrate layer which are stacked in sequence; The solar heat reflection layer comprises a ceramic anti-reflection layer and a metal reflection layer which are alternately stacked in sequence; The thickness of the solar heat reflection layer is 50-500 nm; The number of layers of the ceramic anti-reflection layer is one more than the number of layers of the metal reflective layer; The refractive index of the ceramic anti-reflection layer is greater than 2; The thickness of the ceramic anti-reflection layer is 20-30 nm; The number of layers of the metal reflective layer is 1 to 3; The thickness of the metal reflective layer is 10-25 nm; The high radiation transmittance refrigeration layer is a polymer resin layer with thermal radiation functional ceramic particles uniformly dispersed inside; The particle size of the thermal radiation functional ceramic particles is less than 100 nm; The thickness of the high radiation transmittance refrigeration layer is 1-8 μm.

2. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: In the solar heat reflection layer, the material of the metal reflection layer is selected from at least one of Al, Ag, Ni, and Cd.

3. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: In the solar heat reflection layer, the material of the ceramic anti-reflection layer is selected from at least one of TiO2, Nb2O5, Si3N4, and CeO2.

4. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: The thermal radiation functional ceramic particles are selected from at least one of TiO2, Al2O3, SiO2, Si3N4, and BaSO4.

5. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: A scratch-resistant self-repairing protective layer is also provided on the side of the second polymer substrate layer away from the high radiation transmittance refrigeration layer; The thickness of the scratch-resistant self-repairing protective layer is 1-10 μm.

6. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: The release film layer is a PET film with a thickness of 50-100 μm; The first polymer material layer and the second polymer substrate layer are independently TPU films with a thickness of 50-100 μm; The adhesive layer is a pressure-sensitive adhesive with a thickness of 1 to 5 μm.

7. The highly spectrally selective radiative cooling automobile sunroof film according to claim 1, characterized in that: The highly spectrally selective radiative cooling automobile sunroof film includes the following technical features: Visible light transmittance greater than 75%; and / or, Near infrared light reflectivity greater than 70%; and / or, 8-13um atmospheric window emissivity greater than 97%; and / or, Radiant cooling power greater than 150W / m 2 .

8. The method for preparing the highly spectrally selective radiative cooling automobile sunroof film according to any one of claims 1 to 7, characterized in that: The steps include: S1, after coating a pressure-sensitive adhesive on one side of the first high molecular polymer substrate layer, compounding a release film with the first high molecular polymer substrate layer; S2, sputtering to form a solar heat reflecting layer on a side of the first high molecular polymer substrate layer away from the pressure-sensitive adhesive layer; S3, coating a polymer resin containing heat radiation functional ceramic particles on the side of the solar heat reflection layer away from the first polymer substrate layer to form a high radiation transmittance cooling layer; S4. Laminating a second high molecular polymer substrate layer on the side of the high radiation transmittance cooling layer away from the solar heat reflection layer.

9. The preparation method according to claim 8, characterized in that: After step S4, the method further includes laminating a scratch-resistant self-repairing protective layer on a side of the second high molecular polymer substrate layer away from the high radiation transmittance refrigeration layer.

10. The preparation method according to claim 8, characterized in that: In the step S2, the sputtering to form the solar heat reflection layer includes first sputtering to form a first ceramic anti-reflection layer, and then alternately sputtering a metal reflection layer and a ceramic anti-reflection layer on the first ceramic anti-reflection layer.

11. The preparation method according to claim 10, characterized in that: The sputtering conditions include: a temperature of -15°C to 25°C, a mixed gas of oxygen and argon with a volume ratio of 10 to 100:1 in the chamber, and a sputtering vacuum of 10 -6 Torr, the coating stable pressure is 10 -3 Torr.

12. The preparation method according to claim 10, characterized in that: The sputtering method of the ceramic anti-reflection layer is double rotating cathode and medium frequency reactive magnetron sputtering, and the power of the double rotating cathode and medium frequency reactive magnetron sputtering is 20-50Kw.

13. The preparation method according to claim 10, characterized in that: The sputtering method of the metal reflective layer is single rotating cathode, DC reaction magnetron sputtering, and the power of the single rotating cathode, DC reaction magnetron sputtering is 2-5Kw.

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