Radiation refrigeration automobile skylight ice shell film with self-cleaning function and preparation method thereof

Abstract

This invention belongs to the field of intelligent automotive film technology, specifically relating to a self-cleaning radiative cooling automotive sunroof ice armor film and its preparation method. The self-cleaning radiative cooling automotive sunroof ice armor film has a structure from bottom to top consisting of a release film layer, an ultraviolet absorption layer, a heat insulation layer, a composite adhesive layer, a radiative cooling layer, and a self-cleaning protective layer. The ice armor film prepared by this invention can effectively block near-infrared sunlight to reduce heat entering the vehicle interior, lower the interior temperature, reduce air conditioning load, and save fuel. It also has a high ultraviolet blocking rate of ≥99%, preventing ultraviolet rays from accelerating interior fading and aging and harming passengers. Furthermore, it has a self-cleaning protective layer, reducing the frequency of cleaning. The ice armor film prepared by this invention combines heat insulation comfort, protective safety, and hassle-free cleaning, effectively compensating for the inherent performance deficiencies of sunroof glass.

Description

Technical Field

[0001] This invention belongs to the field of intelligent vehicle film technology, specifically relating to a radiation-cooled automotive sunroof ice film with self-cleaning function and its preparation method. Background Technology

[0002] Car sunroofs typically use thinner glass to reduce vehicle weight and meet design requirements. However, thin glass has limited heat insulation and UV blocking capabilities. During prolonged periods of direct sunlight in summer, significant solar radiation can penetrate the sunroof and enter the car, causing a substantial increase in cabin temperature. This not only reduces passenger comfort but also forces the air conditioning system to operate at high load for extended periods, increasing fuel or electricity consumption. Simultaneously, UV rays accelerate the aging, fading, and cracking of interior materials (such as leather seats and plastic dashboards) and may harm the skin of passengers. Furthermore, the sunroof glass surface is constantly exposed to the external environment, easily accumulating dust, bird droppings, tree sap, and other pollutants. Due to its high position and large area, cleaning and maintenance are inconvenient, and frequent wiping can leave scratches on the glass surface, affecting light transmission and aesthetics.

[0003] Therefore, there is an urgent need for a skylight protection solution that can simultaneously address issues such as heat insulation, UV protection, and easy cleaning. Summary of the Invention

[0004] The purpose of this invention is to provide a radiant cooling car sunroof ice film with self-cleaning function, which takes into account heat insulation comfort, protection and safety and worry-free cleaning, and effectively makes up for the shortcomings of the sunroof glass itself.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The first aspect of this invention provides a self-cleaning radiative cooling automotive sunroof ice film, the structure of which, from bottom to top, consists of a release film layer, an ultraviolet absorption layer, a heat insulation layer, a composite adhesive layer, a radiative cooling layer, and a self-cleaning protective layer; for a detailed structural diagram, see [image / details]. Figure 1 .

[0007] Preferably, the thickness of the self-cleaning radiant cooling sunroof ice film is 150~200μm.

[0008] Preferably, the release film layer is a PET film with a thickness of 25 μm.

[0009] Preferably, the ultraviolet absorption layer is prepared from an ultraviolet absorption layer slurry; the raw materials for preparing the ultraviolet absorption layer slurry include an ultraviolet absorber, an aqueous acrylic resin, and functional additives, in a mass ratio of (3~5):(85~90):(5~10).

[0010] Preferably, the ultraviolet absorber is a benzotriazole ultraviolet absorber, UV-327.

[0011] Preferably, the waterborne acrylic resin is either BASF Acronal ECO7021 / 7022 or Dow Chemical Rhoplex SG-30 / SA200.

[0012] Preferably, the functional additives include thickeners, dispersants, pH adjusters, antioxidants, light stabilizers, leveling agents, defoamers, and preservatives, in a mass ratio of (1~2):(2~3):(0.5~1):(1.5~2):(2~3):(1~2):(0.5~1):(0.5~1):(0.5~1).

[0013] Preferably, the tackifier is one or both of rosin resin and terpene resin.

[0014] Preferably, the dispersant is sodium polyacrylate.

[0015] Preferably, the thickener is hydroxyethyl cellulose.

[0016] Preferably, the pH adjuster is triethanolamine.

[0017] Preferably, the antioxidant is a hindered phenolic antioxidant.

[0018] Preferably, the light stabilizer is a hindered amine HALS.

[0019] Preferably, the leveling agent is a polyether-modified siloxane.

[0020] Preferably, the defoamer is an organosilicone defoamer.

[0021] Preferably, the preservative is an isothiazolinone preservative.

[0022] The method for preparing the ultraviolet absorption layer slurry includes the following steps:

[0023] A small amount of dispersant is mixed with a UV absorber and ground to obtain a ground UV absorber. Aqueous acrylic resin is diluted with deionized water to a viscosity of 900-1000 mPa·s, and pH is adjusted to 6-8 by adding a pH adjuster. The mixture is then poured into a high-speed dispersion kettle, stirred and heated. While stirring, the ground UV absorber and functional additives are added. After stirring for 40-50 minutes, the mixture is pumped into a sand mill and circulated for sand milling at least 3 times until the light transmittance and UV blocking rate of the slurry meet the standards. The mixture is then sealed and stored for use in subsequent coating processes.

[0024] Preferably, the small amount of dispersant is 10% to 30% of the total amount of dispersant.

[0025] Preferably, the grinding speed is 1500~1800 rpm and the grinding time is 1.5~2.5h.

[0026] Preferably, the specific conditions for stirring and heating are: a rotation speed of 1800~2000 rpm and a temperature of 30~35℃.

[0027] Preferably, the specific conditions for the sand milling are as follows: zirconium oxide beads (particle size 0.4 mm) are used as the grinding media, and the sand milling speed is 2200~2500 rpm.

[0028] Preferably, the standards for light transmittance and ultraviolet blocking rate are as follows: visible light transmittance ≥92%, with no obvious turbidity; UVB blocking rate ≥99%, and UVA blocking rate ≥98%.

[0029] The UV-absorbing layer (or adhesive layer) not only absorbs ultraviolet rays from sunlight, providing protection, but also tightly bonds the sunroof armor to the car sunroof glass. The UV-absorbing layer uses water-based acrylic adhesive because it is environmentally friendly, easy to apply, and highly stable, resistant to temperature changes and prolonged sun exposure, making it suitable for the automotive environment. The UV absorber is a benzotriazole light absorber, which converts harmful ultraviolet light energy into harmless heat or low-energy visible light. Benzotriazole light absorbers also possess lightfastness; even with prolonged exposure to sunlight, their molecular structure is not easily damaged by ultraviolet light, allowing them to continue functioning effectively.

[0030] Preferably, the heat insulation layer includes an A side and a B side, wherein the A side is a PET film layer and the B side is a magnetron sputtering layer.

[0031] Preferably, the heat insulation layer is prepared by magnetron sputtering, which deposits metal materials, metal oxide materials, or non-metal oxide materials onto the surface of a PET film.

[0032] Preferably, the metallic material includes one or more of gold, silver, chromium, nickel, aluminum, and titanium; the metal oxide includes one or more of aluminum oxide, titanium dioxide, calcium carbonate, indium tin oxide, and barium sulfate; and the non-metallic oxide includes one or more of silicon dioxide, silicon carbide, and silicon sulfide.

[0033] Preferably, the heat insulation layer is composed of three or more of the above-mentioned materials in a stacked manner, with the number of layers optionally ranging from 6 to 15, and the thickness of each layer ranging from 5 to 30 nm.

[0034] The manufacturing process of the heat insulation layer includes the following steps:

[0035] The PET film is first ultrasonically cleaned and then dried with hot air until the moisture content is ≤0.05%. After plasma treatment, it is uniformly entered into the vacuum chamber for magnetron sputtering through a tension control system. All film layers are deposited and sputtered in the order of the target positions designed for the layer structure. After being cooled by cooling rollers, it is wound into a winding machine in a vacuum environment, wrapped in tin foil, and stored in a 25°C constant temperature warehouse for later use.

[0036] Preferably, the PET film has a thickness of 36 μm and a width of 1520 mm.

[0037] Preferably, the specific conditions for ultrasonic cleaning are as follows: the ultrasonic solution is deionized water containing 0.1% neutral cleaning agent, the temperature is 40-50℃, the ultrasonic power is 500-800W, and the cleaning time is 3-5 mins.

[0038] Preferably, the specific conditions for hot air drying are: temperature of 60~70℃ and wind speed of 2~3m / s.

[0039] Preferably, the specific conditions for plasma treatment are: the gas is argon, the power is 300~500W, the treatment speed is 10~15m / min, until the surface tension increases to ≥45mN / m.

[0040] Preferably, the tension of the tension control system is 5~10N.

[0041] Preferably, before the magnetron sputtering, the vacuum chamber needs to be pretreated. Specifically, this involves using a three-stage vacuum pump (mechanical pump + Roots pump + molecular pump) for 30-60 minutes until the vacuum chamber pressure drops from atmospheric pressure to 1×10⁻⁶. -2 Pa; a cold trap is placed inside the vacuum chamber at a temperature of -120℃ to -150℃ to adsorb residual water vapor and volatile organic compounds; simultaneously, high-purity argon gas (99.999% purity) is introduced twice to flush the vacuum chamber, further removing impurity gases, and finally, the chamber is evacuated until the residual gas is ≤1×10 -4 Pa is sufficient.

[0042] Preferably, during the film deposition sputtering process, an online film thickness monitor configured behind each target position is required to provide real-time feedback on the film thickness and automatically adjust the target power / substrate speed.

[0043] Preferably, the temperature of the cooling roller is 25~30℃; and the tension of the winding machine is 8~12N.

[0044] The heat insulation layer is a composite structure layer composed of multiple layers of metals, metal oxides, and non-metal oxides, prepared by magnetron sputtering. Its main function is to reflect infrared light from sunlight while allowing visible light to pass through. The core of the metal heat insulation film's infrared light reflection lies in the dual effect of "metal free electron response + multilayer film interference." In the metal layer, free electrons vibrate under the influence of the alternating electric field of infrared light, generating reverse electromagnetic waves (i.e., reflecting infrared light). The multilayer "metal + non-metal oxide" structure, through precise control of the refractive index and thickness of the non-metal oxides, enhances the superposition of infrared light reflection while simultaneously reducing and canceling out visible light reflection, ultimately achieving high infrared blocking (heat insulation), high visible light transmittance (lighting), and low reflectivity (ensuring driving safety).

[0045] Preferably, the radiation cooling layer is prepared from a substrate and modified functional particles.

[0046] Preferably, the amount of modified functional particles added accounts for 3% to 5% of the total mass of the substrate and the modified functional particles.

[0047] Preferably, the substrate is a polyether-type aliphatic TPU with a hardness of 85A and a density of 1.2 g / cm³. 3 The tensile strength is 50-54 MPa.

[0048] In some alternative solutions, the polyether-type aliphatic TPU is sourced from Covestro, Germany, specifically Desmopan 385E.

[0049] The method for preparing the modified functional particles includes the following steps: mixing the functional particles and then modifying them with a silane coupling agent to obtain the final product.

[0050] Preferably, the functional particles include at least one of fumed silica and rutile titanium dioxide.

[0051] Preferably, the particle size of the fumed silica is 20-50 nm; and the particle size of the rutile titanium dioxide is 30-50 nm.

[0052] Preferably, the mass ratio of fumed silica to rutile titanium dioxide is (2~3):1; more preferably, it is 7:3.

[0053] Preferably, the silane coupling agent includes KH-550.

[0054] Preferably, the method for preparing the modified functional particles includes the following steps: mixing the functional particles, adding them to a silane coupling agent solution, ultrasonically dispersing them, performing reaction grafting, separating them, washing them three times with anhydrous ethanol, and then vacuum drying them to obtain the final product.

[0055] Preferably, the silane coupling agent in the silane coupling agent solution is KH-550, accounting for 10%, ethanol accounts for 80%, and deionized water accounts for 10%.

[0056] Preferably, the solid-liquid ratio of the functional particles and the silane coupling agent solution is 1g:10mL.

[0057] Preferably, the specific parameters for ultrasonic dispersion are: power of 600W, frequency of 20kHz, dispersion time of 30min, and mechanical stirring speed of 500rpm.

[0058] Preferably, the specific parameters for the reaction grafting are: temperature 80℃, constant temperature stirring reaction for 4 hours.

[0059] Preferably, the specific parameters for vacuum drying are: temperature 80℃, vacuum degree 0.08MPa, and drying time 6h.

[0060] The method for preparing the radiation cooling layer includes the following steps:

[0061] A1. After drying the substrate to a moisture content of ≤0.05%, it is premixed with modified functional particles, granulated and extruded using a twin-screw extruder, water-cooled and pelletized, and then dried to obtain composite masterbatch.

[0062] A2. The composite masterbatch is fed into a casting film machine to form the finished film. After annealing, it is cooled to room temperature to obtain the radiation cooling layer. The film is then rolled up and stored in a constant temperature room for later use.

[0063] Preferably, in step A1, the specific premixing conditions are: rotation speed of 1400~1600 rpm, temperature of 58~62℃, and time of 8~12 min.

[0064] Preferably, in step A1, the specific conditions for granulation extrusion are as follows: L / D=40 granulation, with the following temperatures: feeding section temperature 140~150℃, melting section temperature 170~180℃, mixing section temperature 180~190℃, homogenization section temperature 175~185℃, die temperature 180~185℃, rotation speed 100~200rpm, and vacuum degree ≤1×10⁻⁶. 3 Pa.

[0065] Preferably, in step A1, the particle size of the composite masterbatch is ≤5μm.

[0066] Preferably, in step A2, the specific forming conditions are as follows: screw temperature is 150~185℃, rotation speed is 20~30rpm, die gap is 0.2~0.3mm, three-roll cooling is used, the cooling temperature is 60~70℃, 40~50℃, and 30~40℃, the rotation speed is 3~5m / min, and the traction winding tension is 5~10N.

[0067] Preferably, in step A2, the finished film has the following dimensions: a thickness of 100~150μm and a width of 1520mm.

[0068] Preferably, in step A2, the specific annealing conditions are: nitrogen protection, temperature of 78~82℃, holding temperature of 2h, and cooling rate of 5℃ / min.

[0069] The radiation cooling layer consists of nano-sized inorganic ceramic particles uniformly dispersed in a TPU film. The lattice vibration mode of the ceramic particles matches the energy of infrared light in the 8-13μm band, efficiently converting heat from the substrate and environment into infrared light in this band. This light penetrates the atmosphere and dissipates into the low-temperature universe, actively releasing heat. The particles are uniformly dispersed in the polymer substrate, preserving its flexibility while enhancing overall infrared radiation efficiency through the radiative superposition effect between particles. Furthermore, the substrate's support ensures a stable and long-lasting cooling effect. The substrate uses polyether-type aliphatic TPU, capable of withstanding high and low temperature cycling from -40℃ to 80℃, strong ultraviolet radiation, rain (pH 4-9), and minor scratches. Simultaneously, it must balance film flexibility (avoiding bending and cracking) with light transmittance, making it suitable for automotive sunroofs.

[0070] Preferably, the self-cleaning protective layer is a micron-sized papillary biomimetic structure layer prepared on the radiation cooling layer through nanoimprinting and UV curing processes. The micron-sized papillary structure allows water to form water droplets on the film surface, thereby removing contaminants from the film surface. In addition, the cured polymer material can play a role in preventing scratches and protecting the film material and the skylight glass.

[0071] The specific preparation steps for the self-cleaning protective layer are as follows:

[0072] B1. Surface pretreatment of the radiation cooling layer;

[0073] B2. After coating with UV resin, nano-imprinting and UV curing are performed, the pressure is slowly released, peeled off, and dried to obtain the final product.

[0074] Preferably, in step B1, the surface pretreatment includes surface cleaning and plasma treatment.

[0075] Preferably, the surface cleaning involves wiping the surface of the radiation cooling layer with isopropanol and then drying it.

[0076] Preferably, the specific conditions for plasma treatment are as follows: the gas is a mixture of argon and oxygen in a volume ratio of 8:2, the power is 300~500W, the treatment speed is 1~2m / min, the treatment distance is 5-10mm, and the treatment is carried out until the surface tension is ≥45mN / m.

[0077] Preferably, the raw materials for preparing the UV resin include polyurethane acrylate (PUA) prepolymer, reactive diluent, UV photoinitiator, and nano silica in a mass ratio of (60~70):(20~30):(3~5):(2~5).

[0078] Preferably, the polyurethane acrylate (PUA) prepolymer is a polyether-type PUA with a functionality of 6.

[0079] In some alternative embodiments, the polyurethane acrylate (PUA) prepolymer is sourced from ZINX, EBECRYL8411.

[0080] Preferably, the active diluent is trimethylolpropane triacrylate (TMPTA).

[0081] Preferably, the UV photoinitiator is 1-hydroxycyclohexylphenyl ketone Irgacure 184.

[0082] Preferably, the nano-silica is fumed silica with a particle size of 10~20nm, modified with KH-570 silane coupling agent. The specific modification method is the same as the preparation method of modified functional particles, except that the silane coupling agent is KH-570.

[0083] The preparation method of the UV resin includes the following steps: mixing PUA prepolymer with reactive diluent, adding UV photoinitiator and nano silica under high-speed stirring, continuing to stir for 15-25 minutes, filtering with a 0.22μm organic filter membrane to remove agglomerated particles, and obtaining transparent UV resin.

[0084] Preferably, the specific conditions for high-speed stirring are: temperature of 30°C, rotation speed of 800~1200 rpm, and time of 10~20 min.

[0085] Preferably, the coating thickness of the UV resin is 20~30μm.

[0086] Preferably, during the nanoimprinting and UV curing process, a nickel electroformed micron-sized protrusion mold is used. After coating the mold surface with a fluorosilane release agent, the mold is dried at 115-125°C for 1 hour. The mold imprinting temperature is set to 60-80°C, and the imprinting pressure is 0.5-1 MPa. Under the imprinting pressure holding state, UV light is irradiated from above the mold, with the energy controlled at 800-1200 mJ / cm². 2 The irradiation time is 30~60s.

[0087] Preferably, the structural parameters of the nickel electroforming micron-sized nipple mold are: nipple diameter 5-10 μm, height 8-15 μm, and spacing 10-20 μm.

[0088] In some alternatives, the fluorosilane release agent is DuPont Zonyl FS-300.

[0089] Preferably, the depressurization rate of the slow depressurization is 0.1 MPa / s.

[0090] Preferably, the specific drying conditions are: a temperature of 50°C and a holding time of 2 hours.

[0091] The self-cleaning protective layer is prepared by nanoimprinting a layer of papillary biomimetic microstructure on the surface of a thin film with a hydrophobic angle ≥100°, allowing water to form easily rolling spherical droplets on the surface, thereby actively carrying away the attached pollutants. Essentially, it has the dual function of reducing pollutant adhesion and enhancing pollutant removal.

[0092] The second aspect of the present invention provides a method for preparing the self-cleaning radiation-cooled automotive sunroof ice armor film, comprising the following steps: preparing a self-cleaning protective layer on the surface of the radiation-cooling layer to obtain a TPU radiation-cooling film with a self-cleaning layer; bonding the TPU radiation-cooling film with a self-cleaning layer and the B side of the magnetron sputtering layer of the heat insulation layer with a composite adhesive layer; and then bonding the release film to the A side of the heat insulation layer through an ultraviolet absorption layer to obtain the final product.

[0093] Preferably, the composite adhesive layer is prepared by a composite adhesive, the raw materials for which include polyether-type PU prepolymer, trimethylolpropane triacrylate, UV photoinitiator, and silane coupling agent KH-560, in a mass ratio of (85~90):(4~7):(2~3):(1~2).

[0094] In some alternative solutions, the polyether-type PU prepolymer is derived from Huitian New Materials HT-UV8600 or Loctite AA3966.

[0095] Preferably, the UV photoinitiator is 1-hydroxycyclohexylphenyl ketone Irgacure 184.

[0096] The method for preparing the self-cleaning radiant cooling automotive sunroof ice film includes the following steps:

[0097] S1. A self-cleaning protective layer is prepared on the surface of the radiation cooling layer to obtain a TPU radiation cooling film with a self-cleaning layer.

[0098] S2. Unwind the TPU radiation cooling film with a self-cleaning layer and the heat insulation layer respectively using a tension controller;

[0099] S3. Apply composite adhesive to side B of the heat insulation layer using a micro-grooving coating roller. The wet film thickness is 3-5μm. The coating speed is synchronized with the unwinding speed.

[0100] S4. After bonding the B side of the heat insulation layer with the radiation cooling layer of the TPU radiation cooling film with the self-cleaning layer using a two-roll laminator, UV curing is performed to obtain a PET / TPU composite film.

[0101] S5. Unwind the PET / TPU composite film and release film layer, and use a micro-gravure coating roller to coat the surface of the release film layer with a UV absorption layer slurry with a thickness of 10~20μm. After bonding the PET / TPU composite film and release film layer together, cure to obtain the final product.

[0102] Preferably, in step S2, the tension of the TPU radiation cooling film with the self-cleaning layer is 5~8N, and the tension of the heat insulation layer is 8~10N.

[0103] Preferably, in step S3, both the coating speed and the unwinding speed are 1~2 m / min.

[0104] Preferably, in step S4, the bonding parameters of the twin-roll laminator are: the upper roller is a rubber roller with a pressure of 0.6~0.8MPa, and the lower roller is a metal cooling roller with a temperature of 30℃.

[0105] Preferably, in step S4, the parameters for UV curing are: wavelength 365nm, power 95~105mW / cm². 2 The irradiation length is 0.5m, and the curing time is 3~5s.

[0106] Preferably, in step S5, the unwinding and bonding speeds are both 1~3m / min.

[0107] Preferably, in step S5, the curing parameters are: wavelength 365nm, power 95~105mW / cm². 2 The irradiation length is 0.5m, and the curing time is 3~5s.

[0108] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0109] 1. This invention proposes a radiation-cooled automotive sunroof ice film with self-cleaning function. It is prepared by designing different functional layers and combining them. The prepared ice film can effectively block near-infrared light from the sun to reduce heat entering the car, lower the interior temperature, reduce the air conditioning load, and save fuel. At the same time, it has a high ultraviolet blocking rate of ≥99%, which prevents ultraviolet rays from accelerating the fading and aging of the interior and harming the driver and passengers. It can also transmit visible light.

[0110] 2. The self-cleaning radiation cooling car sunroof ice armor film prepared by this invention has a thickness of 150~200μm. It can stick to the fragments when the sunroof glass is accidentally broken to prevent them from flying and injuring people. It can also resist scratches caused by dust, branches and other debris, and protect the sunroof glass. At the same time, it has a self-cleaning protective layer. When rainwater falls on it, it will form water droplets and roll away the dust, bird droppings and other stains, reducing the frequency of cleaning.

[0111] 3. The radiation cooling car sunroof ice armor film with self-cleaning function prepared by this invention takes into account heat insulation comfort, protection safety and worry-free cleaning, effectively making up for the performance deficiencies of the sunroof glass itself. Attached Figure Description

[0112] Figure 1 This is a structural diagram of the self-cleaning radiation-cooled automotive sunroof ice film prepared according to the present invention. Detailed Implementation

[0113] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0114] All raw materials used in this invention are commercially available, as detailed below:

[0115] The release film is a PET film with a thickness of 25μm, sourced from Yihua Toray Polyester Film Co., Ltd.

[0116] The waterborne acrylic resins are Acronal ECO7021 / 7022 from BASF, and Rhoplex SG-30 / SA200 from Dow Chemical.

[0117] The rosin resins are PENSEL GA-90 and GA-85, sourced from Arakawa Chemical.

[0118] Terpene resin T-801L, from Arakawa Chemical.

[0119] Sodium polyacrylate is Acusol 445N, sourced from Dow Chemical.

[0120] Hydroxyethyl cellulose, designated QP-30000H, is from Dow Chemical.

[0121] The hindered phenolic antioxidant is Irganox 1010, sourced from BASF.

[0122] The hindered amine HALS is Tinuvin 292, derived from BASF.

[0123] The polyether-modified siloxane is BYK-333, sourced from BYK Chemicals.

[0124] The silicone defoamer is BYK-024, sourced from BYK Chemicals.

[0125] The isothiazolinone preservative is KATHON LXE (1.5%), from Dow Chemical.

[0126] The heat insulation PET film, 36μm thick and 1520mm wide, is from Yihua Toray Polyester Film Co., Ltd.

[0127] Polyether-type aliphatic TPU, with a hardness of 85A and a density of 1.2 g / cm³. 3 It has a tensile strength of 50-54 MPa and is from Covestro, Germany, Desmopan 385E.

[0128] Fumed silica, with a particle size of 20~50nm, is from Evonik in Germany.

[0129] The rutile titanium dioxide has a particle size of 30~50nm and comes from Longbai Group.

[0130] Polyether-type PUA with a functionality of 6, from Zhanxin, EBECRYL 8411.

[0131] Nano-silica is fumed silica with a particle size of 10~20nm, modified with KH-570 silane coupling agent. The specific modification method is the same as the preparation method of modified functional particles, the only difference being that the silane coupling agent is KH-570; the fumed silica with a particle size of 10~20nm is from Evonik, Germany.

[0132] The polyether-type PU prepolymer is derived from Huitian New Materials HT-UV8600 or Loctite AA3966.

[0133] The neutral cleaning agent is KX-608, a water-based cleaning agent for PET optical films, sourced from Kexi Chemical.

[0134] Fluorosilane release agent, from DuPont Zonyl FS-300.

[0135] Example 1

[0136] This embodiment provides a self-cleaning radiation-cooled automotive sunroof ice film, the structure of which, from bottom to top, consists of a release film layer, an ultraviolet absorption layer, a heat insulation layer, a composite adhesive layer, a radiation-cooling layer, and a self-cleaning protective layer.

[0137] The thickness of the self-cleaning radiation-cooled automotive sunroof ice armor film is 150~200μm.

[0138] The release film layer is a PET film with a thickness of 25 μm.

[0139] The ultraviolet absorption layer is prepared from an ultraviolet absorption layer slurry; the raw materials for preparing the ultraviolet absorption layer slurry include an ultraviolet absorber, a water-based acrylic resin, and functional additives, in a mass ratio of 3:85:5.

[0140] The ultraviolet absorber is a benzotriazole ultraviolet absorber, UV-327.

[0141] The waterborne acrylic resin is Acronal ECO7021, sourced from BASF.

[0142] The functional additives include thickeners, dispersants, pH adjusters, antioxidants, light stabilizers, leveling agents, defoamers, and preservatives, in a mass ratio of 1:2:0.5:1.5:2:1:0.5:0.5:0.5.

[0143] The tackifier is PENSEL GA-90 rosin resin.

[0144] The dispersant is sodium polyacrylate.

[0145] The thickener is hydroxyethyl cellulose.

[0146] The pH adjuster is triethanolamine.

[0147] The antioxidant is a hindered phenolic antioxidant.

[0148] The light stabilizer is a hindered amine HALS.

[0149] The leveling agent is a polyether-modified siloxane.

[0150] The defoamer is an organosilicone defoamer.

[0151] The preservative is an isothiazolinone preservative.

[0152] The preparation method of the ultraviolet absorption layer slurry includes the following steps:

[0153] A small amount of dispersant and UV absorber are mixed and ground to obtain a ground UV absorber. Aqueous acrylic resin is diluted with deionized water to a viscosity of 950 mPa·s, and pH is adjusted to 7.5 by adding a pH adjuster. The mixture is then poured into a high-speed dispersion kettle, stirred and heated. While stirring, the ground UV absorber and functional additives are added. After stirring for 40 minutes, the mixture is pumped into a sand mill and circulated for sand milling at least 3 times until the light transmittance and UV blocking rate of the slurry meet the standards. The mixture is then sealed and stored for use in subsequent coating processes.

[0154] The small amount of dispersant is 10% of the total amount of dispersant.

[0155] The grinding speed was 1500 rpm and the time was 1.5 h.

[0156] The specific conditions for stirring and heating are: a rotation speed of 1800 rpm and a temperature of 35°C.

[0157] The specific conditions for the sand milling are as follows: zirconium oxide beads (0.4 mm in diameter) are used as the grinding media, and the sand milling speed is 2200 rpm.

[0158] The standards for transmittance and UV blocking rate are as follows: visible light transmittance ≥92%, with no obvious turbidity; UVB blocking rate ≥99%, and UVA blocking rate ≥98%.

[0159] The heat insulation layer includes an A side and a B side, wherein the A side is a PET film layer and the B side is a magnetron sputtering layer.

[0160] The heat insulation layer is prepared by depositing metal materials, metal oxide materials, and non-metal oxide materials onto the surface of a PET film using a magnetron sputtering process.

[0161] The magnetron sputtering layer system is: SiO2→TiO2→SiO2→Cr→Ag→SiO2→TiO2→SiO2→Ag→SiO2→TiO2→SiO2→TiO2, with a thickness of 10nm→15nm→10nm→20nm→10nm→10nm→15nm→10nm→10nm→10nm→15nm→10nm→15nm→10nm→15nm.

[0162] The preparation process of the heat insulation layer includes the following steps:

[0163] The PET film is first ultrasonically cleaned and then dried with hot air until the moisture content is ≤0.05%. After plasma treatment, it is uniformly entered into the vacuum chamber for magnetron sputtering through a tension control system. All film layers are deposited and sputtered in the order of the target positions designed for the layer structure. After being cooled by cooling rollers, it is wound into a winding machine in a vacuum environment, wrapped in tin foil, and stored in a 25°C constant temperature warehouse for later use.

[0164] The specific conditions for ultrasonic cleaning are as follows: the ultrasonic solution is deionized water containing 0.1% neutral cleaning agent, the temperature is 40℃, the ultrasonic power is 600W, and the cleaning time is 5mins.

[0165] The specific conditions for hot air drying are: temperature 65℃ and wind speed 3m / s.

[0166] The specific conditions for plasma treatment are as follows: the gas is argon, the power is 500W, the treatment speed is 10m / min, until the surface tension increases to ≥45mN / m.

[0167] The tension of the tension control system is 5N.

[0168] Before magnetron sputtering, the vacuum chamber needs to be pretreated. Specifically, a three-stage vacuum pump consisting of a mechanical pump, a Roots pump, and a molecular pump is used to evacuate the vacuum chamber for 30 minutes until the pressure drops from atmospheric pressure to 1×10⁻⁶. -2 Pa; a cold trap is placed inside the vacuum chamber at a temperature of -120℃ to adsorb residual water vapor and volatile organic compounds; simultaneously, high-purity argon gas (99.999% purity) is introduced twice to flush the vacuum chamber, further removing impurity gases, and finally, the chamber is evacuated until the residual gas is ≤1×10 -4 Pa is sufficient.

[0169] During the film deposition sputtering process, the online film thickness monitor configured behind each target site needs to provide real-time feedback on the film thickness and automatically adjust the target power / substrate speed.

[0170] The temperature of the cooling roller is 25°C; the tension of the winding machine is 8N.

[0171] The radiation cooling layer is made of a substrate and modified functional particles.

[0172] The amount of the modified functional particles added accounts for 5% of the total mass of the substrate and the modified functional particles.

[0173] The substrate is polyether-type aliphatic TPU.

[0174] The preparation method of the modified functional particles includes the following steps: mixing the functional particles, adding them to a silane coupling agent solution, ultrasonically dispersing them, reacting and grafting them, separating them, washing them three times with anhydrous ethanol, and then vacuum drying them to obtain the final product.

[0175] The functional particles are fumed silica (20 nm) and rutile titanium dioxide (50 nm) in a mass ratio of 7:3.

[0176] The silane coupling agent solution contains KH-550 as 10%, ethanol as 80%, and deionized water as 10%.

[0177] The solid-liquid ratio of the functional particles and the silane coupling agent solution is 1 g: 10 mL.

[0178] The specific parameters for ultrasonic dispersion are: power of 600W, frequency of 20kHz, dispersion time of 30min, and mechanical stirring speed of 500rpm.

[0179] The specific parameters for the grafting reaction are: temperature 80℃, constant temperature stirring reaction for 4h.

[0180] The specific parameters for vacuum drying are: temperature 80℃, vacuum degree 0.08MPa, and drying time 6h.

[0181] The method for preparing the radiation cooling layer includes the following steps:

[0182] A1. After drying the substrate to a moisture content of 0.05%, it is premixed with modified functional particles, granulated and extruded using a twin-screw extruder, water-cooled and pelletized, and then dried to obtain composite masterbatch.

[0183] A2. The composite masterbatch is fed into a casting film machine to form the finished film. After annealing, it is cooled to room temperature to obtain the radiation cooling layer. The film is then rolled up and stored in a constant temperature room for later use.

[0184] In step A1, the specific premixing conditions are: rotation speed of 1500 rpm, temperature of 60℃, and time of 10 min.

[0185] In step A1, the specific conditions for granulation extrusion are as follows: L / D = 40 granulation, feeding section temperature 140℃, melting section temperature 170℃, mixing section temperature 180℃, homogenization section temperature 175℃, die temperature 180℃, rotation speed 150rpm, and vacuum degree ≤1×10 3 Pa.

[0186] In step A1, the particle size of the composite masterbatch is ≤5μm.

[0187] In step A2, the specific forming conditions are as follows: screw temperature is 170℃, rotation speed is 20rpm, die gap is 0.2mm, three-roll cooling with cooling temperatures of 60℃, 40℃, and 30℃, rotation speed is 3m / min, and traction winding tension is 7N.

[0188] In step A2, the finished membrane obtained has the following dimensions: thickness of 120 μm and width of 1520 mm.

[0189] In step A2, the specific annealing conditions are: nitrogen protection, temperature of 80℃, holding temperature of 2h, and cooling rate of 5℃ / min.

[0190] The self-cleaning protective layer is a micron-scale papillary biomimetic structure layer prepared on the radiation cooling layer through nanoimprinting and UV curing processes.

[0191] The specific preparation steps for the self-cleaning protective layer are as follows:

[0192] B1. Surface pretreatment of the radiation cooling layer;

[0193] B2. After coating with UV resin, nano-imprinting and UV curing are performed, the pressure is slowly released, peeled off, and dried to obtain the final product.

[0194] In step B1, the surface pretreatment includes surface cleaning and plasma treatment.

[0195] The surface cleaning process involves wiping the surface of the radiation cooling layer with isopropanol and then drying it.

[0196] The specific conditions for plasma treatment are as follows: the gas is a mixture of argon and oxygen in a volume ratio of 8:2, the power is 300W, the treatment speed is 1m / min, the treatment distance is 5mm, and the treatment is carried out until the surface tension is ≥45mN / m.

[0197] The raw materials for preparing the UV resin include polyurethane acrylate (PUA) prepolymer, reactive diluent, UV photoinitiator, and nano silica in a mass ratio of 60:20:3:2.

[0198] The polyurethane acrylate (PUA) prepolymer is a polyether-type PUA with a functionality of 6.

[0199] The active diluent is trimethylolpropane triacrylate (TMPTA).

[0200] The UV photoinitiator is 1-hydroxycyclohexylphenyl ketone Irgacure 184.

[0201] The nano-silica is fumed silica with a particle size of 20 nm, modified with KH-570 silane coupling agent. The specific modification method is the same as the preparation method of modified functional particles, except that the silane coupling agent is KH-570.

[0202] The preparation method of the UV resin includes the following steps: mixing PUA prepolymer with reactive diluent, adding UV photoinitiator and nano silica under high-speed stirring, continuing to stir for 20 minutes, filtering with a 0.22μm organic filter membrane to remove agglomerated particles, and obtaining transparent UV resin.

[0203] The specific conditions for high-speed stirring are: temperature 30℃, rotation speed 1000rpm, and time 15min.

[0204] The coating thickness of the UV resin is 20 μm.

[0205] During the nanoimprinting and UV curing process, a nickel electroformed micron-sized protrusion mold was used. After coating the mold surface with a fluorosilane release agent, the mold was dried at 110°C for 1 hour. The mold imprinting temperature was set to 70°C, and the imprinting pressure was 0.8 MPa. Under the imprinting pressure holding state, UV light was irradiated from above the mold, with the energy controlled at 1000 mJ / cm². 2 The irradiation time is 45 seconds.

[0206] The structural parameters of the nickel electroforming micron-sized nipple mold are: nipple diameter 5μm, height 8μm, and spacing 10μm.

[0207] The depressurization rate of the slow depressurization is 0.1 MPa / s.

[0208] The specific drying conditions are: temperature of 50℃ and holding time of 2 hours.

[0209] The method for preparing the self-cleaning radiation-cooled automotive sunroof ice armor film includes the following steps: preparing a self-cleaning protective layer on the surface of the radiation-cooling layer to obtain a TPU radiation-cooling film with a self-cleaning layer; bonding the TPU radiation-cooling film with a self-cleaning layer and the B side of the magnetron sputtering layer of the heat insulation layer with a composite adhesive layer; and then bonding the release film to the A side of the heat insulation layer through an ultraviolet absorption layer to obtain the final product.

[0210] The composite adhesive layer is prepared by a composite adhesive, the raw materials for which include polyether-type PU prepolymer, trimethylolpropane triacrylate, UV photoinitiator, and silane coupling agent KH-560, in a mass ratio of 85:4:2:1.

[0211] The polyether-type PU prepolymer is derived from Huitian New Materials HT-UV8600 or Loctite AA3966.

[0212] The UV photoinitiator is 1-hydroxycyclohexylphenyl ketone Irgacure 184.

[0213] The preparation method of the self-cleaning radiant cooling automotive sunroof ice film includes the following steps:

[0214] S1. A self-cleaning protective layer is prepared on the surface of the radiation cooling layer to obtain a TPU radiation cooling film with a self-cleaning layer.

[0215] S2. Unwind the TPU radiation cooling film with a self-cleaning layer and the heat insulation layer respectively using a tension controller;

[0216] S3. Apply composite adhesive to the B side of the heat insulation layer using a micro-grooving coating roller. The wet film thickness is 5μm. The coating speed is synchronized with the unwinding speed.

[0217] S4. After bonding the B side of the heat insulation layer with the radiation cooling layer of the TPU radiation cooling film with the self-cleaning layer using a two-roll laminator, UV curing is performed to obtain a PET / TPU composite film.

[0218] S5. Unwind the PET / TPU composite film and release film layer, apply a UV absorption layer slurry with a thickness of 10μm to the surface of the release film layer using a micro-gravure coating roller, and then bond the PET / TPU composite film and release film layer together and cure to obtain the final product.

[0219] In step S2, the tension of the TPU radiation cooling film with the self-cleaning layer is 5N, and the tension of the heat insulation layer is 8N.

[0220] In step S3, both the coating speed and the unwinding speed are 2 m / min.

[0221] In step S4, the bonding parameters of the twin-roll laminator are as follows: the upper roller is a rubber roller with a pressure of 0.8 MPa, and the lower roller is a metal cooling roller with a temperature of 30°C.

[0222] In step S4, the parameters for UV curing are: wavelength 365nm, power 105mW / cm². 2 The irradiation length is 0.5m and the curing time is 5s.

[0223] In step S5, the unwinding and bonding speeds are both 2 m / min.

[0224] In step S5, the parameters for UV curing are: wavelength 365nm, power 100mW / cm². 2 The irradiation length is 0.5m and the curing time is 5s.

[0225] Example 2

[0226] This embodiment provides a self-cleaning radiant cooling car sunroof ice film, the specific implementation of which is the same as in Embodiment 1, except that:

[0227] The raw materials for preparing the ultraviolet absorption layer slurry, the mass ratio of ultraviolet absorber, water-based acrylic resin, and functional additives is 5:90:10.

[0228] The waterborne acrylic resin is Rhoplex SG-30.

[0229] The mass ratio of the viscous agent, dispersant, thickener, pH adjuster, antioxidant, light stabilizer, leveling agent, defoamer, and preservative in the functional additive is 2:3:1:2:3:2:1:1:1.

[0230] The tackifier is a terpene resin.

[0231] The preparation method of the ultraviolet absorption layer slurry includes the following steps:

[0232] A small amount of dispersant and UV absorber are mixed and ground to obtain a ground UV absorber. Aqueous acrylic resin is diluted with deionized water to a viscosity of 1000 mPa·s, and pH is adjusted to 8 by adding a pH adjuster. The mixture is then poured into a high-speed dispersion kettle, stirred and heated. While stirring, the ground UV absorber and functional additives are added. After stirring for 50 minutes, the mixture is pumped into a sand mill and circulated for sand milling at least 3 times until the light transmittance and UV blocking rate of the slurry meet the standards. The mixture is then sealed and stored for use in subsequent coating processes.

[0233] The small amount of dispersant is 30% of the total amount of dispersant.

[0234] The grinding speed was 1800 rpm and the time was 2.5 h.

[0235] The specific conditions for stirring and heating are: a rotation speed of 2000 rpm and a temperature of 30°C.

[0236] The specific conditions for the sand milling are as follows: zirconium oxide beads (0.4 mm in diameter) are used as the grinding media, and the sand milling speed is 2500 rpm.

[0237] The magnetron sputtered film system of the heat insulation layer is as follows: TiO2→SiO2→TiO2→Cr→Ag→TiO2→SiO2→TiO2→SiO2→Ag→TiO2→SiO2→TiO2→SiO2, a total of 14 layers. The thickness of each layer is as follows: 15nm→12nm→18nm→8nm→20nm→15nm→12nm→18nm→12nm→18nm→15nm→12nm→18nm→12nm.

[0238] The amount of the modified functional particles added accounts for 3% of the total mass of the substrate and the modified functional particles.

[0239] The mass ratio of the fumed silica (20 nm) to the rutile titanium dioxide (50 nm) is 2:1.

[0240] In step A1 of the preparation of the radiation cooling layer, the premixing speed is 1600 rpm, the temperature is 62℃, and the time is 12 min; the temperature of the granulation extrusion feeding section is 150℃, the temperature of the melting section is 180℃, the temperature of the mixing section is 190℃, the temperature of the homogenization section is 185℃, the die temperature is 185℃, and the rotation speed is 200 rpm.

[0241] In step A2, the screw temperature is 185℃, the rotation speed is 30rpm, the die gap is 0.3mm, the cooling temperatures of the three rollers are 60℃, 50℃, and 40℃ respectively, the traction and winding tension is 10N, the finished film thickness is 150μm, and the annealing temperature is 82℃.

[0242] The raw materials for preparing the UV resin of the self-cleaning protective layer are polyurethane acrylate (PUA) prepolymer, reactive diluent, UV photoinitiator, and nano silica in a mass ratio of 70:30:5:5.

[0243] In the raw materials for preparing the UV resin, the nano-silica is fumed silica with a particle size of 15nm, which is modified by KH-570 silane coupling agent. The specific modification method is the same as the preparation method of modified functional particles, except that the silane coupling agent is KH-570.

[0244] The UV resin was prepared by high-speed stirring at 1200 rpm for 20 minutes.

[0245] During the nanoimprinting and UV curing process, the coating thickness is 20 μm; the mold drying temperature is 125℃; the imprinting temperature is 80℃; the imprinting pressure is 1 MPa; and the UV energy is 1200 mJ / cm². 2 The irradiation time is 60 seconds.

[0246] The structural parameters of the nickel electroforming micron-sized nipple mold are: nipple diameter 10μm, height 15μm, and spacing 20μm.

[0247] The raw materials for preparing the composite adhesive are polyether-type PU prepolymer, trimethylolpropane triacrylate, UV photoinitiator, and silane coupling agent KH-560 in a mass ratio of 90:7:3:2.

[0248] The polyether-type PU prepolymer is Loctite AA3966.

[0249] In the method for preparing the ice armor film, the thickness of the composite adhesive wet film is 3μm; the thickness of the ultraviolet absorption layer slurry coating is 20μm; the tension of the TPU radiation cooling film with the self-cleaning layer is 8N, and the tension of the heat insulation layer is 10N; the unwinding, coating, and lamination speeds are all 1m / min.

[0250] Comparative Example 1

[0251] The only difference between this comparative example and Example 1 is:

[0252] The mass ratio of fumed silica to rutile titanium dioxide is 9:1.

[0253] Comparative Example 2

[0254] The only difference between this comparative example and Example 1 is:

[0255] In the preparation step of the self-cleaning protective layer, the nano-silica in the raw material of the UV resin is replaced with micron-sized silica with a particle size of 1~5μm, which comes from Beijing Zhongke Keyou Technology Co., Ltd.

[0256] Comparative Example 3

[0257] The only difference between this comparative example and Example 1 is:

[0258] The structural parameters of the nickel electroforming micron-sized nipple mold are: nipple diameter 15μm, height 5μm, and spacing 30μm.

[0259] Comparative Example 4

[0260] The only difference between this comparative example and Example 1 is:

[0261] In the magnetron sputtering layer of the heat insulation layer, Ag and Cr are completely replaced with TiO2 layers, while the thickness remains unchanged, to form a multilayer film of all oxides.

[0262] Comparative Example 5

[0263] The only difference between this comparative example and Example 1 is:

[0264] The A side of the TPU radiation cooling film with a self-cleaning layer and the magnetron sputtering layer with the heat insulation layer are bonded together with a composite adhesive layer, and then the release film is bonded to the B side of the heat insulation layer through an ultraviolet absorption layer.

[0265] Comparative Example 6

[0266] The only difference between this comparative example and Example 1 is:

[0267] In the preparation of the composite adhesive, the polyether-type PU prepolymer was replaced with a polyester-type PU prepolymer, T100T80PTMG, from Zibo Zhuoyue Technology Development Co., Ltd.

[0268] Comparative Example 7

[0269] The only difference between this comparative example and Example 1 is:

[0270] In the self-cleaning protective layer, the polyurethane acrylate (PUA) prepolymer has a functionality of 2 and is sourced from ZNX, EBECRYL8215.

[0271] Comparative Example 8

[0272] The only difference between this comparative example and Example 1 is:

[0273] The magnetron sputtering layer system consists of 5 layers, in the following order: SiO2→TiO2→Ag→TiO2→SiO2, with each layer having a thickness of 20nm→15nm→20nm→10nm→30nm.

[0274] Performance testing

[0275] The infrared and ultraviolet light blocking properties of the ice-resistant film were tested in accordance with GA / T744-2013, and the visible light transmittance was also tested.

[0276] According to GB / T30127-2013, the average emissivity of the atmospheric window band exceeded 90%, and the radiative cooling power was tested.

[0277] The hydrophobic angle was tested according to GB / T30693-2014.

[0278] All performance test results are shown in Table 1.

[0279] Table 1 Performance Test Results

[0280]

[0281] As shown in Table 1, the self-cleaning radiation-cooled automotive sunroof ice film prepared in Examples 1-2 can effectively block near-infrared sunlight to reduce heat entering the vehicle, lower the interior temperature, reduce the air conditioning load, and save fuel. It also has a high UV blocking rate of ≥99%, preventing ultraviolet rays from accelerating interior fading and aging and harming passengers. In addition, it has good light transmission, high radiation cooling power, greatly reducing the energy consumption of automotive air conditioning, and a high hydrophobic angle, which can play a self-cleaning role.

[0282] In Comparative Example 1, the mass ratio of fumed silica to rutile titanium dioxide is outside the scope of this invention. In Comparative Example 2, the nano-silica in the raw materials of UV resin is replaced with micron-sized silica. In Comparative Example 3, the structural parameters of the nickel electroforming micron-sized protrusion mold are outside the scope of this invention. In Comparative Example 4, the magnetron sputtering layer film system in the heat insulation layer does not have a metal material layer. In Comparative Example 5, the heat insulation layer sequence is reversed. In Comparative Example 6, the polyether-type PU prepolymer is replaced with a polyester-type PU prepolymer in the raw materials for preparing the composite adhesive. In Comparative Example 7, the functionality of the polyurethane acrylate (PUA) prepolymer in the self-cleaning protective layer is 2. In Comparative Example 8, the number of magnetron sputtering layer film systems is small. The performance of the prepared self-cleaning radiation cooling car sunroof ice armor film is reduced.

[0283] Therefore, this invention proposes a self-cleaning radiative cooling automotive sunroof ice film, which effectively blocks near-infrared sunlight to reduce heat entering the vehicle interior, lowering the interior temperature and reducing air conditioning load, thus saving fuel. It also boasts a high UV blocking rate of ≥99%, preventing UV rays from accelerating interior fading and aging and harming passengers, while allowing visible light to pass through. Furthermore, it features a self-cleaning protective layer; rainwater droplets form and roll away dust, bird droppings, and other stains, reducing cleaning frequency. The ice film prepared by this invention combines heat insulation and comfort, protective safety, and hassle-free cleaning, effectively compensating for the inherent performance limitations of sunroof glass.

[0284] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A self-cleaning radiant cooling automotive sunroof ice film, characterized in that, Its structure, from bottom to top, consists of a release film layer, an ultraviolet absorption layer, a heat insulation layer, a composite adhesive layer, a radiation cooling layer, and a self-cleaning protective layer; the ultraviolet absorption layer is prepared from an ultraviolet absorption layer slurry; the heat insulation layer includes an A side and a B side, wherein the A side is a PET film layer and the B side is a magnetron sputtering layer; The ultraviolet absorption layer slurry is prepared from ultraviolet absorbers, water-based acrylic resins, and functional additives in a mass ratio of (3~5):(85~90):(5~10).

2. The self-cleaning radiant cooling automotive sunroof ice film according to claim 1, characterized in that, The heat insulation layer is prepared by depositing metal materials, metal oxide materials, and non-metal oxide materials onto the surface of a PET film using a magnetron sputtering process.

3. The self-cleaning radiant cooling automotive sunroof ice film according to claim 2, characterized in that, The metallic material includes one or more of gold, silver, chromium, nickel, aluminum, and titanium; the metal oxide includes one or more of aluminum oxide, titanium dioxide, calcium carbonate, indium tin oxide, and barium sulfate; and the non-metallic oxide includes one or more of silicon dioxide, silicon carbide, and silicon sulfide.

4. The self-cleaning radiant cooling automotive sunroof ice film according to claim 3, characterized in that, The heat insulation layer is composed of three or more of the above-mentioned materials, stacked in a layered manner, with the number of layers optionally ranging from 6 to 15, and the thickness of each layer ranging from 5 to 30 nm.

5. The self-cleaning radiant cooling automotive sunroof ice film according to claim 1, characterized in that, The radiation cooling layer is made of a substrate and modified functional particles.

6. The self-cleaning radiant cooling automotive sunroof ice film according to claim 5, characterized in that, The amount of the modified functional particles added accounts for 3% to 5% of the total mass of the substrate and the modified functional particles.

7. The self-cleaning radiant cooling automotive sunroof ice film according to claim 6, characterized in that, The substrate is a polyether-based aliphatic TPU with a hardness of 85A and a density of 1.2 g / cm 3 and a tensile strength of 50-54 MPa.

8. The self-cleaning radiant cooling automotive sunroof ice film according to claim 1, characterized in that, The self-cleaning protective layer is a micron-scale papillary biomimetic structure layer prepared on the radiation cooling layer through nanoimprinting and UV curing processes.

9. A method for preparing a self-cleaning radiant cooling automotive sunroof ice film according to any one of claims 1 to 8, characterized in that, Includes the following steps: A self-cleaning protective layer is prepared on the surface of the radiation cooling layer to obtain a TPU radiation cooling film with a self-cleaning layer; the TPU radiation cooling film with a self-cleaning layer and the B side of the magnetron sputtering layer of the heat insulation layer are bonded together with a composite adhesive layer, and then the release film is bonded to the A side of the heat insulation layer through an ultraviolet absorption layer to obtain the final product.

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