Heat-insulating and weather-resistant material, preparation method and application of heat-insulating and weather-resistant material to car cover

Abstract

The invention discloses a heat-insulating and weather-resistant material, a preparation method and application of the heat-insulating and weather-resistant material to car clothing in the field of polymer composites.The heat-insulating and weather-resistant material comprises a surface layer, a middle layer and a bottom layer and is characterized in that the surface layer is prepared from, by mass, modified acrylic resin; the preparation method comprises the following steps: preparing SiO2 and CeO2 ceramic microspheres; a near-infrared absorbing pigment; a light response repairing microcapsule; the middle layer is prepared from the following raw materials: polyurethane / polycarbonate alloy; the preparation method comprises the following steps: preparing mullite / Al2O3-SiO2 aerogel; the preparation method comprises the following steps: modifying montmorillonite Sb2O3; the bottom layer raw material comprises a carbon nanotube / graphene heterojunction; the invention relates to an epoxy-acrylic hybrid resin. When the prepared material is applied to the car cover, the heat insulation temperature difference of 25 DEG C or above, efficient flame retardance and good weather resistance can be achieved, and the bottleneck that a traditional material is single in function and unbalanced in performance is broken through.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a heat-insulating and weather-resistant material, its preparation method, and its application in car covers. Background Technology

[0002] The automotive protective materials industry has long faced a technical bottleneck: the difficulty in simultaneously improving heat insulation and weather resistance. Traditional reflective car covers rely on metal coatings or ceramic particles to reflect sunlight, but the bonding strength between the surface layer and the substrate is weak. Prolonged outdoor use can lead to delamination and peeling, and the lack of an active repair mechanism significantly shortens the protective lifespan. Some enhanced solutions improve heat insulation by adding a high proportion of inorganic fillers, but this severely sacrifices material flexibility, failing to meet the mechanical requirements of repeated folding and storage, while also accelerating the aging and cracking of the substrate.

[0003] Existing flame-retardant modification technologies mostly employ physical doping of flame retardants, which can improve fire safety. However, the flame-retardant components have poor compatibility with polymers, which not only reduces the mechanical strength of the material but also causes component migration failure in humid and hot environments. Especially under extreme climates such as high temperature and humidity and strong ultraviolet radiation, traditional car covers generally exhibit yellowing, embrittlement, and functional degradation, making it difficult to maintain long-term stable protection.

[0004] Current car cover products have highly limited functionality, with their heat insulation, weather resistance, and flame retardancy properties mutually constraining each other, failing to overcome the fundamental limitations of material system design. Advanced functions such as intelligent sensing are difficult to integrate due to a lack of compatible substrates, hindering real-time temperature monitoring or self-healing capabilities. The industry urgently needs a new composite material that can balance high-efficiency heat insulation, extreme environment tolerance, and multi-functional synergy to address the comprehensive protection needs in complex usage scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide a heat-insulating and weather-resistant material, a preparation method, and its application in car covers. It overcomes the shortcomings of traditional car cover materials in that it is difficult to coordinate heat insulation, weather resistance, and flexibility, breaks through the bottleneck of mechanical property degradation caused by the addition of flame retardants, and solves the problems of functional limitation and lack of intelligent response.

[0006] The present invention achieves the above objectives through the following technical solutions: A heat-insulating and weather-resistant material comprises a surface layer, an intermediate layer, and a bottom layer. By mass percentage, the surface layer comprises: modified acrylic resin: 40-60%; SiO2@CeO2 ceramic microspheres: 15-20%; near-infrared absorbing pigments: 10-15%; and photoresponsive repair microcapsules: 5-8%. The intermediate layer comprises: polyurethane / polycarbonate alloy: 60-70%; mullite / Al2O3-SiO2 aerogel: 20-30%; and modified montmorillonite-Sb2O3: 10-15%. The bottom layer comprises: carbon nanotube / graphene heterostructure: 3-5%; and epoxy-acrylic hybrid resin: 85-92%. The preparation method of the SiO2@CeO2 ceramic microspheres includes: slowly adding tetraethyl orthosilicate dropwise into an ethanol / water solution containing 0.1 mol / L hexadecyltrimethylammonium bromide surfactant, stirring at 40°C to generate monodisperse SiO2 microspheres; centrifuging and washing until neutral, and drying at 60°C; dissolving cerium nitrate (Ce(NO3)3·6H2O) in deionized water, adding citric acid, and stirring at 80°C to form a transparent sol; immersing the SiO2 microspheres in the CeO2 sol, ultrasonically dispersing, and allowing to stand; centrifuging and pre-drying at 80°C; placing the coated microspheres in a muffle furnace and calcining at 500°C to crystallize CeO2 and form a shell.

[0007] In this invention, the carboxyl and epoxy groups of the modified acrylic resin in the surface layer undergo a cross-linking reaction during UV curing to form a dense network, providing a stable carrier for the functional filler.

[0008] In this invention, SiO2@CeO2 ceramic microspheres are calcined at high temperature to decompose cerium nitrate into CeO2 crystals. Oxygen vacancies in the crystal lattice capture high-energy electrons excited by ultraviolet light, while CeO2... 3+ / Ce 4+ Redox cycles consume free radicals, significantly inhibiting resin photoaging; near-infrared absorbing pigments contain metal complexes that selectively absorb photons of specific wavelengths and convert them into non-radiative thermal energy for diffusion.

[0009] According to a preferred embodiment of the present invention, the modified acrylic resin is HD160 type purchased from Laiyang Hongan Chemical Co., Ltd.

[0010] According to a preferred embodiment of the present invention, the near-infrared absorbing pigment is purchased from Qingdao Senquan Optoelectronics Co., Ltd., model IR-1085.

[0011] According to a preferred embodiment of the present invention, the polyurethane was purchased from Jiangsu Sanmu Group Co., Ltd.

[0012] According to a preferred embodiment of the present invention, the polycarbonate was purchased from Ningbo Dafeng Jiangning New Material Technology Co., Ltd.

[0013] According to a preferred embodiment of the present invention, the polyurethane / polycarbonate alloy is purchased from Bayer DP3070A.

[0014] In this invention, the polyurethane / polycarbonate alloy in the intermediate layer forms a hydrogen-bonded interpenetrating network during melt blending. The urethane bonds of the polyurethane and the carbonate bonds of the polycarbonate generate dipole interactions to improve interfacial compatibility.

[0015] According to a preferred embodiment of the present invention, the tetraethyl orthosilicate was purchased from Shandong Fengpan New Materials Co., Ltd.

[0016] According to a preferred embodiment of the present invention, the hexadecyltrimethylammonium bromide was purchased from Jinan Juyang Chemical Technology Co., Ltd.

[0017] According to a preferred embodiment of the present invention, the ethanol was purchased from Nantong Runfeng Petrochemical Co., Ltd.

[0018] According to a preferred embodiment of the present invention, the Ce(NO3)3·6H2O was purchased from Shandong Desheng New Materials Co., Ltd.

[0019] According to a preferred embodiment of the present invention, the citric acid was purchased from Hunan Dongting Citric Acid Chemical Co., Ltd.

[0020] According to a preferred embodiment of the present invention, the muffle furnace was purchased from Nanjing Kejie Testing Technology Development Co., Ltd.

[0021] According to a preferred embodiment of the present invention, the method for preparing the carbon nanotube / graphene heterostructure includes: placing a copper foil in a tube furnace, introducing an argon-hydrogen mixture (Ar2 / H2=4:1), annealing at 950°C for 30 min to remove surface oxides; introducing methane (CH4, flow rate 20 sccm), maintaining 950°C and 10 Pa pressure for 15 min, to generate a single layer of graphene on the copper foil surface; dispersing multi-walled carbon nanotubes (diameter 20-30 nm) in a 1 wt% SDS aqueous solution, and sonicating for 1 h (power 300 W); immersing the graphene / copper foil in the carbon nanotube dispersion, and allowing it to stand at 60°C for 2 h to allow the carbon nanotubes to self-assemble and adhere to the graphene surface; spin-coating a PMMA protective layer (spin-coating speed 3000 rpm, thickness 200 nm), etching the copper foil, and then transferring it to the target substrate; vacuum drying (80°C, 2 h) to remove residual solvent and form a stable heterostructure.

[0022] According to a preferred embodiment of the present invention, the copper foil was purchased from Kin Tao Copper Foil Group Limited.

[0023] According to a preferred embodiment of the present invention, the tubular furnace was purchased from Shenzhen Sanli Technology Co., Ltd.

[0024] According to a preferred embodiment of the present invention, the argon-hydrogen mixture is purchased from Shenzhen Baisheng Gas Trading Co., Ltd.

[0025] According to a preferred embodiment of the present invention, the methane was purchased from Sichuan Runtian Special Gases Co., Ltd.

[0026] According to a preferred embodiment of the present invention, the multi-walled carbon nanotubes were purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd.

[0027] According to a preferred embodiment of the present invention, the SDS (sodium dodecyl sulfate) aqueous solution was purchased from Shanghai Enzyme-Link Biotechnology Co., Ltd.

[0028] According to a preferred embodiment of the present invention, the graphene was purchased from Wuxi Huadong Zinc Shield Technology Co., Ltd.

[0029] According to a preferred embodiment of the present invention, the PMMA (polymethyl methacrylate) was purchased from LG Chem in South Korea.

[0030] According to a preferred embodiment of the present invention, the specific steps of the mullite / Al2O3-SiO2 aerogel are as follows: First, aluminum sol is prepared using aluminum sec-butoxide as the aluminum source and ethanol / deionized water as the solvent, and obtained by a two-step acid-base catalytic method; then, silica sol is prepared using water glass prepared from silicon sources such as rice husk ash, and generated by a two-step acid-base catalytic method; next, the silica sol is added to the aluminum sol and stirred, and propylene oxide solution is added to initiate gelation, forming an Al2O3-SiO2 composite sol; then, mullite fiber felt with a density of 0.25 g / cm³ is impregnated in the Al2O3-SiO2 composite sol, maintaining a molar ratio of fiber felt to sol of 1:2; the mixture is allowed to stand until the sol transforms into a gel, forming a mullite fiber-reinforced composite wet gel; the wet gel is aged using ethanol and n-hexane to replace internal moisture and impurities; finally, supercritical drying is performed using CO2 medium: critical temperature 31℃, critical pressure 7.4℃. After processing at MPa for 4 hours and removing the solvent, a mullite fiber-reinforced Al2O3-SiO2 aerogel composite material was obtained.

[0031] In this invention, the silanol groups on the surface of mullite fibers condense with the aluminum oxide bonds in Al2O3-SiO2 sol to form Al-O-Si covalent bonds, constructing a bipolar porous aerogel framework during supercritical drying. The micropores inhibit convective heat transfer by restricting the movement of air molecules, while the mesopores scatter infrared radiation. After sodium-modified montmorillonite is expanded, the alkyl chains of sodium stearate are inserted into the interlayer to enhance hydrophobicity, and its carboxyl groups are ionicly bonded to the aluminum oxide layer of montmorillonite. During heat treatment, the zinc ions generated by the decomposition of zinc stearate form a zinc antimonate capping layer with Sb2O3, which synergistically catalyzes the polymer to form char and releases flame-retardant gases during combustion.

[0032] According to a preferred embodiment of the present invention, the aluminum sec-butoxide was purchased from Yangzhou Zhongtianli New Material Co., Ltd.

[0033] According to a preferred embodiment of the present invention, the propylene oxide solution was purchased from Jinan Huifengda Chemical Co., Ltd.

[0034] According to a preferred embodiment of the present invention, the mullite fiber felt was purchased from Qinyang Kerui Crystal Fiber Co., Ltd.

[0035] According to a preferred embodiment of the present invention, the n-hexane was purchased from Changzhou Aohua Chemical Co., Ltd.

[0036] According to a preferred embodiment of the present invention, the CO2 medium is purchased from Shanghai Tianru Special Gases Co., Ltd.

[0037] According to a preferred embodiment of the present invention, the epoxy-acrylic hybrid resin is DER663U, purchased from Guangzhou Mingda Chemical Co., Ltd.

[0038] According to a preferred embodiment of the present invention, the alcohol-water mass ratio in the ethanol / water solution is 0.6:1; stirring at 40°C for 6 hours; the average particle size of the SiO2 microspheres is 533 nm; drying at 60°C for 12 hours; the molar ratio of cerium ions to citric acid is 1:1.5; ultrasonic dispersion for 30 minutes, standing for 2 hours; pre-drying at 80°C for 2 hours; and calcination at 500°C for 4 hours with a heating rate of 2°C / min.

[0039] According to a preferred embodiment of the present invention, the preparation steps of the photoresponsive repair microcapsules include: mixing dicyclopentadiene with 1% Span-80 emulsifier, stirring in a water bath at 60°C to form a homogeneous oil phase; adding dropwise to an aqueous phase containing 2% PVA, and shearing emulsifying to form an O / W emulsion; adding isophorone diisocyanate and 1,4-butanediol chain extender to the emulsion; reacting at 75°C, whereby isophorone diisocyanate and the chain extender polymerize at the oil-water interface to form a polyurethane wall material; cooling the reaction solution to room temperature and centrifuging.

[0040] In this invention, the polyurethane wall material of the photoresponsive repair microcapsule generates free radicals under ultraviolet light, which initiates the ring-opening polymerization of dicyclopentadiene, and the liquid core material solidifies into a film to fill the scratches.

[0041] According to a preferred embodiment of the present invention, the dicyclopentadiene was purchased from Shandong Weijin Chemical Technology Co., Ltd.

[0042] According to a preferred embodiment of the present invention, the Span-80 emulsifier was purchased from Guangdong Huana Chemical Co., Ltd.

[0043] According to a preferred embodiment of the present invention, the isophorone diisocyanate was purchased from Wuhan Kanos Technology Co., Ltd.

[0044] According to a preferred embodiment of the present invention, the 1,4-butanediol was purchased from Liaoning Aoke Chemical Co., Ltd.

[0045] According to a preferred embodiment of the present invention, the stirring speed in the 60°C water bath is 500 rpm; the high-speed shear emulsification speed is 10,000 rpm and the time is 15 min; the droplet size is 3–5 μm; and the reaction is carried out at 75°C for 4 h.

[0046] According to a preferred embodiment of the present invention, the preparation steps of the modified montmorillonite-Sb2O3 include: mixing montmorillonite raw ore powder with a 5% Na2CO3 solution, wherein the solid-liquid ratio is 1:10, stirring at 80°C for 2 h, centrifuging and washing until neutral, and drying at 105°C; dispersing sodium-modified montmorillonite in water, adding sodium stearate at 10% of the mass of montmorillonite, stirring at 85°C for 3 h; filtering and drying at 60°C, and grinding through a 300-mesh sieve; ball milling and mixing the modified montmorillonite and Sb2O3 at a mass ratio of 3:1; heat-treating the mixed powder at 140°C for 1 h to enhance interfacial bonding.

[0047] According to a preferred embodiment of the present invention, the montmorillonite ore powder was purchased from Inner Mongolia Aimu Chemical Co., Ltd.

[0048] According to a preferred embodiment of the present invention, the Na2CO3 solution was purchased from Shanghai Xinyu Biotechnology Co., Ltd.

[0049] According to a preferred embodiment of the present invention, the sodium stearate was purchased from Qiandao Lake Oil and Fat Chemical Plant in Chun'an County.

[0050] In this invention, the epoxy-acrylic hybrid resin at the bottom layer undergoes ring-opening of the epoxy groups and copolymerization with the acrylate double bonds during curing to form an interpenetrating network. The surface defect sites of the carbon nanotubes and the sp² carbon at the edge of the graphene are connected by C-C bonds to form a three-dimensional conductive pathway. Temperature changes enhance phonon scattering at the heterojunction interface, causing an electron tunneling effect and achieving a linear resistance response. Hot pressing between the three layers allows the surface acrylate free radicals to react with the polyurethane amino groups in the middle layer to form covalent bonds. The bottom epoxy resin permeates the pores of the middle layer to form a mechanical interlock, ultimately constructing an integrated reflective, heat-insulating, and sensing protection system.

[0051] The present invention also provides a method for preparing the aforementioned heat-insulating and weather-resistant material, comprising the following steps: S1, mullite fiber felt is impregnated in Al2O3-SiO2 sol and supercritically dried to obtain mullite fiber reinforced Al2O3-SiO2 aerogel; polycarbonate and polyurethane are melt-blended at 60:40, and mullite fiber reinforced Al2O3-SiO2 aerogel and modified montmorillonite-Sb2O3 are added, and granulated by twin-screw extrusion. S2, SiO2@CeO2 ceramic microspheres were immersed in cerium nitrate solution and ultrasonically treated for 30 min, then washed and dried to obtain SiO2@CeO2 coated powder; modified acrylic resin was ball-milled and mixed with SiO2@CeO2 coated powder, near-infrared absorbing pigment, and photoresponsive repair microcapsules, and coated on the surface of the intermediate layer and cured under ultraviolet light. S3, epoxy-acrylic hybrid resin incorporating carbon nanotubes / graphene, coated on the other side of the intermediate layer, and hot-pressed; laser etching forms a serpentine circuit.

[0052] According to a preferred embodiment of the present invention, in step S1, the density of the mullite fiber felt is 0.25 g / cm³, and the molar ratio of the mullite fiber felt to Al₂O₃-SiO₂ sol is 1:2; the supercritical drying conditions are: CO₂ medium, Tc=31℃, Pc=7.4MPa, t=4h; the twin-screw extrusion temperature is 230-300℃, and the screw speed is 300 r / min.

[0053] According to a preferred embodiment of the present invention, in step S2, the average particle size of the SiO2@CeO2 ceramic microspheres is 5 μm; the ultrasonic treatment time is 30 min; the wavelength of ultraviolet curing is 365 nm and the intensity is 800 mJ / cm².

[0054] According to a preferred embodiment of the present invention, in step S3, the hot pressing temperature is 140°C, the pressure is 1200N, and the time is 90s.

[0055] The present invention also provides an application of the heat-insulating and weather-resistant material described above or the heat-insulating and weather-resistant material prepared by the preparation method described above in car covers.

[0056] The beneficial effects of this invention are as follows: The heat-insulating and weather-resistant material prepared in this invention achieves an unprecedented breakthrough in comprehensive performance through a unique three-layer composite structure design. The surface material is based on a specially modified resin matrix, uniformly dispersing ceramic microspheres with highly efficient light-reflecting capabilities. These microspheres undergo careful coating to form a dense protective layer, which can significantly reflect solar radiation energy under strong sunlight, significantly reducing heat absorption, while simultaneously endowing the material with excellent resistance to ultraviolet radiation, effectively delaying surface aging. More importantly, the photoresponsive repair unit introduced into the surface layer can autonomously repair minor surface damage caused by daily use under the triggering of sunlight and ultraviolet radiation, maintaining the material's appearance integrity and functionality, and greatly extending its service life.

[0057] The intermediate layer, serving as the core thermal insulation barrier, employs a lightweight, porous aerogel composite system. This system, through a special fiber reinforcement and sol-gel composite process, forms a stable bi-level porous structure, effectively blocking heat transfer paths and preventing external heat from penetrating even when exposed to sustained high temperatures. Simultaneously, the flame-retardant synergistic system within the intermediate layer undergoes precise organic-inorganic composite modification, achieving highly uniform dispersion within the polymer matrix. Upon contact with fire, it rapidly forms a dense barrier layer, inhibiting flame spread and preventing the release of toxic fumes. This perfectly balances fire safety and material mechanical strength, completely resolving the industry problem of material embrittlement and loss of toughness caused by traditional flame-retardant additives.

[0058] The bottom layer innovatively integrates an intelligent sensor network, utilizing the unique electrical response characteristics of nanomaterials to sense temperature changes in real time, forming a continuous and stable signal transmission channel. The special adhesive used in this layer not only provides strong and durable interfacial adhesion, ensuring that the multilayer structure does not separate under complex stress, but also possesses excellent weather resistance. It can maintain chemical stability and physical properties even in harsh environments such as long-term exposure to wind and rain, and alternating hot and cold temperatures, providing reliable protection for the upper functional materials.

[0059] Compared to traditional single-layer or simple double-layer car cover materials, this invention completely overcomes the inherent defects of limited functionality, short lifespan, and difficult maintenance. For the first time, it integrates advanced functions such as high-efficiency heat insulation, extreme weather resistance, intelligent sensing, and active protection into one unit. It achieves self-repair and self-warning without the need for external energy intervention, significantly reducing usage costs and maintenance frequency. Its flexible and lightweight characteristics facilitate installation and storage, and its strong environmental adaptability allows for stable service from scorching deserts to frigid mountains. It provides automobiles and other outdoor equipment with an all-weather, intelligent, long-life, high-quality protective solution, redefining the technical standards for next-generation multifunctional protective materials. Detailed Implementation

[0060] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0061] I. Implementation Examples Example 1 First, SiO2@CeO2 ceramic microspheres were prepared: 53.2 g of tetraethyl orthosilicate was slowly added dropwise to a solution containing 14.55 g (0.1 mol / L) hexadecyltrimethylammonium bromide in 180 g of ethanol and 300 g of water, and stirred at 40 °C for 6 h to generate SiO2 microspheres; the microspheres were centrifuged (8000 rpm, 15 min) and washed with ethanol / water (1:1) until neutral, and dried at 60 °C for 12 h; 21.7 g of Ce(NO3)3·6H2O was dissolved in 100 g of deionized water, and 12.6 g of citric acid was added (cerium ion:citric acid = 1:1.5 molar ratio), and stirred at 80 °C to form a transparent sol; the SiO2 microspheres were immersed in the sol, ultrasonically dispersed (300 W, 40 kHz) for 30 min, and allowed to stand for 2 h; the microspheres were then centrifuged (8000 rpm, 15 min) and dried at 60 °C for 12 h. Pre-dry at 80℃ for 2 hours (10 min at rpm); place the coated microspheres in a muffle furnace and calcine at 500℃ for 4 hours at 2℃ / min to obtain 75g of core-shell microspheres.

[0062] Simultaneously, photoresponsive repair microcapsules were prepared: 23.76 g of dicyclopentadiene was mixed with 0.24 g of 1% Span-80 and stirred at 500 rpm for 30 min in a 60°C water bath; the mixture was then added dropwise to an aqueous phase containing 2% PVA (6 g PVA + 294 g water) and emulsified at 10,000 rpm for 15 min to form an O / W emulsion (droplet size 3.2 ± 0.8 μm); 4.8 g of isophorone diisocyanate and 1.2 g of 1,4-butanediol chain extender were added to the emulsion; the reaction was carried out at 75°C for 4 h (stirring at 200 rpm) to allow polyurethane to polymerize at the interface; the reaction solution was cooled to 25°C in an ice-water bath and centrifuged (5000 rpm, 5 min) to collect 24 g of microcapsules.

[0063] Preparation of mullite / Al2O3-SiO2 aerogel: 125g of mullite fiber felt (density 0.25g / cm³) was immersed in Al2O3-SiO2 sol (tetraethyl orthosilicate:aluminum isopropoxide = 2:1 molar ratio, total amount 300g) and vacuum impregnated 3 times (-0.1MPa, 30min); the wet gel was placed in an autoclave, the solvent was replaced by liquid CO2 and then supercritically dried at 31℃ / 7.4MPa for 4h with a depressurization rate of 0.1MPa / min to obtain 150g of aerogel.

[0064] Preparation of modified montmorillonite-Sb2O3: 60g of raw montmorillonite powder was mixed with 600g of 5% Na2CO3 solution and stirred at 80℃ for 2h (200 rpm); the mixture was centrifuged and washed until the conductivity of the filtrate was <50μS / cm, and dried at 105℃ for 12h; sodium-modified montmorillonite was dispersed in 600g of water, 6g of sodium stearate was added, and the mixture was stirred at 85℃ for 3h; after filtration, the mixture was dried at 60℃ and ball-milled through a 300-mesh sieve; 56.25g of modified montmorillonite and 18.75g of Sb2O3 were mixed by planetary ball milling (400 rpm, 2h); the mixed powder was heat-treated at 140℃ for 1h to obtain 75g of composite powder.

[0065] A premixed mixture of 325g polyurethane / polycarbonate alloy, 150g mullite / Al2O3-SiO2 aerogel, and 75g modified montmorillonite-Sb2O3 was granulated using a twin-screw extruder (zone 1: 230℃ / zone 2: 260℃ / zone 3: 300℃, screw speed: 300 rpm) to obtain an intermediate layer. 75g of SiO2@CeO2 ceramic microspheres were immersed in a 0.5mol / L Ce(NO3)3 solution and sonicated (300W) for 30min. After washing and drying, the mixture was mixed with 165g modified acrylic resin, 45g near-infrared absorbing pigment, and 24g photoresponsive repair microcapsules using a planetary ball mill (200 rpm, 1h). This mixture was then coated onto the surface of the intermediate layer (wet film thickness: 200μm) and cured under 365nm UV light (800mJ / cm²). 2 The surface layer is formed by grinding 8g of carbon nanotube / graphene heterostructure into 184g of epoxy-acrylic hybrid resin, and then coated on the other side of the intermediate layer (150μm thick) after three-roll milling (roller gap 0.1mm, 3 times). The bottom layer is formed by hot pressing at 140℃ (1200N, 90s). Finally, a serpentine circuit with a linewidth of 50μm and a spacing of 100μm is etched on the bottom layer using an ultraviolet laser (355nm, 20W).

[0066] Example 2 The total amount of raw materials for the surface layer is 300g: 180g modified acrylic resin, 45g SiO2@CeO2 ceramic microspheres, 45g near-infrared absorbing pigment, and 30g photoresponsive repair microcapsules. The total amount of raw materials for the intermediate layer is 550g: 325g polyurethane / polycarbonate alloy, 150g mullite / Al2O3-SiO2 aerogel, and 75g modified montmorillonite-Sb2O3. The total amount of raw materials for the bottom layer is 192g: 8g carbon nanotube / graphene heterostructure, and 184g epoxy-acrylic hybrid resin. The preparation process is the same as in Example 1.

[0067] Example 3 The total amount of raw materials for the surface layer is 300g: 150g modified acrylic resin, 75g SiO2@CeO2 ceramic microspheres, and 75g near-infrared absorbing pigment. The raw materials for the intermediate and bottom layers are the same as in Example 1. The preparation process is the same as in Example 1.

[0068] Comparative Example 1 The total amount of raw materials for the intermediate layer is 500g: 425g polyurethane / polycarbonate alloy, 75g ordinary SiO2 aerogel (unreinforced), and 75g modified montmorillonite-Sb2O3. The raw materials for the surface and bottom layers are the same as in Example 1. The preparation process is the same as in Example 1.

[0069] Comparative Example 2 The total amount of raw materials for the bottom layer is 200g: 192g of epoxy-acrylic hybrid resin (without conductive materials). The raw materials for the surface layer and intermediate layer are the same as in Example 1. The preparation process is the same as in Example 1.

[0070] Comparative Example 3 The raw material ratio is the same as in Example 1. The process is simplified: SiO2@CeO2 ceramic microspheres are dried at 200℃ (not calcined at 500℃); microcapsules are directly coated with dimercyclopentadiene (interface-free polymerization); aerogels are dried at atmospheric pressure (not supercritical drying); laser etching is eliminated.

[0071] II. Performance Testing The materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing according to the following methods: 1. Thermal insulation performance test: According to GB / T 10295-2008, the sample (10cm×10cm) was vertically irradiated using a solar simulator (irradiance 1000W / m², spectral range 280-2500nm). The temperature difference ΔT (°C) between the inner and outer surfaces of the material was recorded using thermocouples. The data acquisition interval was 10s, and the stable value was obtained after 30min.

[0072] 2. Weather resistance test: Refer to ASTM G154 and use QUV accelerated aging tester. Cyclic conditions: UVB-313 lamp irradiation (0.76W / m²@340nm) 4h / 60℃ → condensation 4h / 50℃, total duration 2000h; After aging, the adhesion is evaluated according to ISO 2409 cross-cut test (blade spacing 1mm), the ΔE value is measured with a colorimeter (D65 light source), and the cracking / chalking grade is visually inspected.

[0073] 3. Self-healing efficiency test: A microblade was used to make a surface scratch (20mm long × 50μm deep), and the surface was irradiated with a 365nm ultraviolet light source (100mW / cm²) for 10 minutes; the tensile strength of the scratch before and after repair was measured (GB / T 1040.3), and the calculation formula was: Repair efficiency (%) = [σ max (After repair) / σ max [(Original)]×100%.

[0074] 4. Conductivity test: According to GB / T 1410, the surface resistivity of the bottom layer (S / cm) is measured by a four-probe resistance meter; De-icing function test: The sample is covered with an aluminum plate (ice thickness 1mm) at -20℃, a voltage of 12V is applied, and the time for the ice layer to completely detach is recorded.

[0075] 5. Material performance test results: Table 1: Performance test results of each embodiment and comparative example

[0076] As shown in Table 1, the embodiments of this invention innovatively and synergistically solve the key defects of traditional car cover materials through a three-layer composite structure: In terms of thermal insulation, the mullite fiber reinforced Al2O3-SiO2 aerogel (thermal conductivity 0.023 W / (m·K)) in Example 1 works synergistically with the surface SiO2@CeO2 ceramic microspheres (near-infrared reflectivity >90%) to achieve a ΔT of 28.5℃, which is 55.7% higher than that of Comparative Example 1 (ordinary aerogel, ΔT=18.3℃), overcoming the thermal insulation failure caused by the easy sedimentation of low thermal conductivity fillers in traditional materials; In terms of weather resistance and flexibility, the middle layer of polyurethane / polycarbonate alloy (tensile strength 38MPa) and montmorillonite-Sb2O3 (flame retardant oxygen index 32.5) form a rigid-flexible interpenetrating network, QUV Even after 2000 hours, it still maintains a level 0 adhesion (comparative example 1 cracked to level 4), and does not break even with a bending radius of 2mm, breaking through the bottleneck of traditional flame retardants (such as pure Sb2O3) becoming brittle when added to more than 15%; in terms of intelligent functions, the surface photoresponsive microcapsules (92% repair rate after 10 minutes of light exposure) and the bottom laser-etched serpentine circuit (2.8 minutes / -20℃ de-icing time) integrate self-repair and active de-icing functions, solving the problem of the single function of traditional car covers (comparative example 3 has a repair rate of only 35%, and comparative example 2 cannot de-ic, achieving a leap in integrated performance of "heat insulation-weather resistance-intelligent response".

[0077] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A heat-insulating and weather-resistant material, comprising a surface layer, an intermediate layer, and a bottom layer, characterized in that, By weight percentage, the surface layer material comprises: modified acrylic resin: 40-60%; SiO2@CeO2 ceramic microspheres: 15-20%; near-infrared absorbing pigments: 10-15%; photoresponsive repair microcapsules: 5-8%; the intermediate layer material comprises: polyurethane / polycarbonate alloy: 60-70%; mullite / Al2O3-SiO2 aerogel: 20-30%; modified montmorillonite-Sb2O3: 10-15%; the bottom layer material comprises: carbon nanotube / graphene heterostructure: 3-5%; epoxy-acrylic hybrid resin: 85-92%. The preparation method of the SiO2@CeO2 ceramic microspheres includes: slowly adding tetraethyl orthosilicate dropwise into an ethanol / water solution containing 0.1 mol / L hexadecyltrimethylammonium bromide surfactant, stirring at 40°C to generate monodisperse SiO2 microspheres; centrifuging and washing until neutral, and drying at 60°C; dissolving Ce(NO3)3·6H2O in deionized water, adding citric acid, and stirring at 80°C to form a transparent sol; immersing the SiO2 microspheres in the CeO2 sol, ultrasonically dispersing, and allowing to stand; centrifuging and pre-drying at 80°C; placing the coated microspheres in a muffle furnace and calcining at 500°C to crystallize CeO2 and form a shell.

2. The heat-insulating and weather-resistant material according to claim 1, characterized in that, The ethanol / water solution had a mass ratio of 0.6:1; the mixture was stirred at 40°C for 6 hours; the average particle size of the SiO2 microspheres was 533 nm; the mixture was dried at 60°C for 12 hours; the molar ratio of cerium ions to citric acid was 1:1.5; the mixture was ultrasonically dispersed for 30 minutes and allowed to stand for 2 hours; it was pre-dried at 80°C for 2 hours; and then calcined at 500°C at a rate of 2°C / min for 4 hours.

3. The heat-insulating and weather-resistant material according to claim 1, characterized in that, The preparation steps of the photoresponsive repair microcapsules include: mixing dicyclopentadiene with 1% Span-80 emulsifier, stirring in a 60°C water bath to form a homogeneous oil phase; adding dropwise to an aqueous phase containing 2% PVA, and shearing emulsifying to form an O / W emulsion; adding isophorone diisocyanate and 1,4-butanediol chain extender to the emulsion; reacting at 75°C, where isophorone diisocyanate and chain extender polymerize at the oil-water interface to form a polyurethane wall material; cooling the reaction solution to room temperature and centrifuging.

4. The heat-insulating and weather-resistant material according to claim 3, characterized in that, The stirring speed in the 60℃ water bath was 500 rpm; the high-speed shear emulsification speed was 10,000 rpm and the time was 15 min; the droplet size was 3–5 μm; and the reaction was carried out at 75℃ for 4 h.

5. The heat-insulating and weather-resistant material according to claim 1, characterized in that, The preparation steps of the modified montmorillonite-Sb2O3 include: mixing raw montmorillonite powder with 5% Na2CO3 solution, wherein the solid-liquid ratio is 1:10, stirring at 80℃ for 2 h, centrifuging and washing until neutral, and drying at 105℃; dispersing sodium-modified montmorillonite in water, adding sodium stearate of 10% of the montmorillonite mass, stirring at 85℃ for 3 h; filtering and drying at 60℃, grinding through a 300-mesh sieve; ball milling and mixing the modified montmorillonite and Sb2O3 at a mass ratio of 3:1; heat-treating the mixed powder at 140℃ for 1 h to enhance interfacial bonding.

6. A method for preparing a heat-insulating and weather-resistant material according to any one of claims 1-5, characterized in that, Includes the following steps: S1, mullite fiber felt is impregnated in Al2O3-SiO2 sol and supercritically dried to obtain mullite fiber reinforced Al2O3-SiO2 aerogel; polycarbonate and polyurethane are melt-blended at 60:40 to obtain polyurethane / polycarbonate alloy, and mullite fiber reinforced Al2O3-SiO2 aerogel and modified montmorillonite-Sb2O3 are added, and granulated by twin-screw extrusion. S2, SiO2@CeO2 ceramic microspheres were immersed in cerium nitrate solution and ultrasonically treated for 30 min, then washed and dried to obtain SiO2@CeO2 coated powder; modified acrylic resin was ball-milled and mixed with SiO2@CeO2 coated powder, near-infrared absorbing pigment, and photoresponsive repair microcapsules, and coated on the surface of the intermediate layer and cured under ultraviolet light. S3, epoxy-acrylic hybrid resin incorporating carbon nanotubes / graphene, coated on the other side of the intermediate layer, and hot-pressed; laser etching forms a serpentine circuit.

7. The preparation method according to claim 6, characterized in that, In step S1, the density of the mullite fiber felt is 0.25 g / cm³, and the molar ratio of the mullite fiber felt to Al₂O₃-SiO₂ sol is 1:2; the supercritical drying conditions are: CO₂ medium, Tc=31℃, Pc=7.4MPa, t=4h; the twin-screw extrusion temperature is 230-300℃, and the screw speed is 300 r / min.

8. The preparation method according to claim 6, characterized in that, In step S2, the average particle size of the SiO2@CeO2 ceramic microspheres is 5 μm; the ultrasonic treatment time is 30 min; the wavelength of ultraviolet curing is 365 nm and the intensity is 800 mJ / cm².

9. The preparation method according to claim 6, characterized in that, In step S3, the hot pressing temperature is 140℃, the pressure is 1200N, and the time is 90s.

10. The application of a heat-insulating and weather-resistant material according to any one of claims 1-5 or a heat-insulating and weather-resistant material prepared by the preparation method according to any one of claims 6-9, characterized in that, The application of the heat-insulating and weather-resistant material in car covers.

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