A wear-resistant coating for a drone shell and a method of making the same

Abstract

This invention belongs to the field of coating technology and provides a wear-resistant coating for drone shells and its preparation method. The raw materials of the coating include: hydrogenated bisphenol A epoxy resin, vinyl-terminated fluorinated polybutadiene resin, core-shell powder, aluminum borate nanofibers, polyetherimide micro powder, wear-resistant additives, silane coupling agent KH-792, light stabilizer, leveling agent and environmentally friendly solvent. The preparation method includes: (1) mixing hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene resin to form a resin matrix; (2) first adding core-shell powder and aluminum borate nanofibers to the resin matrix for dispersion; after cooling to 25-30℃, adding other raw materials, stirring and defoaming to obtain the finished product. This coating has high wear resistance, wind and sand erosion resistance, low temperature crack resistance, microcrack self-repair, strong UV aging resistance and high adhesion, which can significantly improve the long-term service stability and service life of drone shells in complex and harsh environments such as high altitude, wind and sand, high and low temperature alternation, and strong ultraviolet radiation.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a wear-resistant coating for the shell of a drone and its preparation method. Background Technology

[0002] As a core product in high-end equipment manufacturing and next-generation information technology, unmanned aerial vehicles (UAVs) have been widely used in industrial and civilian fields such as surveying and inspection, security monitoring, emergency rescue, logistics and transportation, and resource exploration. During long-term operations in actual high-altitude, field, and complex weather conditions, the UAV's outer shell is subjected to multiple severe tests, including wind and sand erosion, particle impact, drastic temperature fluctuations, strong ultraviolet radiation, and mechanical vibration. The wear resistance, structural stability, weather resistance, and mechanical reliability of its surface protective coating directly determine the overall service life and flight safety of the UAV.

[0003] Currently, the protective coatings used for drone shells on the market are still mainly based on conventional acrylic resins, polyurethane resins, epoxy resins and their simple modified products. Although they can meet basic protection requirements, they have exposed obvious technical shortcomings and performance defects in complex working conditions and long-term use.

[0004] First, existing drone shell coatings generally suffer from insufficient wear resistance and weak erosion resistance. Conventional coatings rely on the simple addition of inorganic rigid fillers to increase hardness. The bond between the filler and the resin is only physical, resulting in weak interfacial adhesion. Under long-term wind and sand erosion and high-speed impact from particles, the coating is prone to scratches, wear, exposure of the substrate, and chalking, failing to provide continuous and reliable wear protection for the drone shell. Simultaneously, the addition of hard fillers increases the coating's brittleness, leading to decreased toughness and further exacerbating the risk of wear and cracking, making it difficult to withstand the continuous mechanical impacts of high-altitude, high-speed flight.

[0005] Secondly, most traditional coatings lack the ability to self-heal microcracks. During frequent takeoffs and landings, high and low temperature cycles, and mechanical vibrations, microcracks are easily generated inside the coating of drones. Current technology cannot actively repair these microcracks, which will continue to expand under external stress, moisture, and ultraviolet radiation, eventually leading to coating cracking, peeling, and detachment. This leaves the outer shell substrate unprotected, resulting in corrosion, aging, or structural damage, seriously threatening flight safety.

[0006] Secondly, existing coatings suffer from poor low-temperature toughness and insufficient environmental adaptability. In low-temperature environments such as high altitudes, cold regions, and high-altitude winters, conventional resin systems are prone to embrittlement, resulting in increased coating hardness and a sharp drop in toughness. Even slight impacts can cause cracking, chipping, and peeling, failing to meet the all-terrain, all-weather requirements of UAVs.

[0007] Furthermore, traditional coating systems have weak resistance to ultraviolet aging. Under long-term exposure to strong ultraviolet radiation at high altitudes, the resin is prone to oxidation, chain breakage, and degradation, leading to rapid yellowing, loss of gloss, chalking, and decreased adhesion, resulting in short service life, frequent maintenance and replacement, and high operating costs. Simultaneously, problems such as uneven filler dispersion, insufficient interfacial bonding strength, and poor resin-filler compatibility are common, resulting in insufficient overall structural stability of the coating and making it difficult to meet the long-term service requirements of high-end unmanned aerial vehicles (UAVs).

[0008] In summary, the current lack of a dedicated protective coating for drone shells that can simultaneously achieve high wear resistance, resistance to wind and sand erosion, low-temperature crack resistance, self-healing of microcracks, strong weather resistance, and high adhesion has become a significant technical bottleneck restricting the improvement of drone reliability and the expansion of application scenarios. Summary of the Invention

[0009] To address the aforementioned shortcomings in the existing technology, the present invention aims to provide a wear-resistant coating for drone shells and its preparation method. This coating utilizes a stable interpenetrating cross-linked network formed by hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene resin, combined with a specially formulated core-shell structured powder filler, and synergistically incorporates aluminum borate nanofibers, polyetherimide micropowder, and wear-resistant and weather-resistant additives. This constructs an integrated protective system that combines high wear resistance, resistance to wind and sand erosion, low-temperature crack resistance, micro-crack self-repair, strong UV aging resistance, and high adhesion. This significantly improves the long-term service stability and service life of drone shells in complex and harsh environments such as high altitudes, wind and sand, alternating high and low temperatures, and strong UV radiation.

[0010] To achieve the above objectives, the solution adopted by the present invention is as follows: A wear-resistant coating for the shell of a drone, comprising, by weight, the following raw materials: 35-42 parts of hydrogenated bisphenol A epoxy resin with an epoxy equivalent of 180-220 g / eq, 12-18 parts of vinyl-terminated fluorinated polybutadiene resin, 7-11 parts of core-shell powder, 2-4 parts of aluminum borate nanofibers with a diameter of 20-40 nm, 1-2 parts of polyetherimide micropowder with a particle size of 500-800 nm, 0.6-1.0 parts of wear-resistant additive, 0.4-0.8 parts of silane coupling agent KH-792, 1.2-1.6 parts of light stabilizer, 0.2-0.5 parts of leveling agent, and 16-22 parts of environmentally friendly solvent; the preparation of the vinyl-terminated fluorinated polybutadiene resin includes: (1) adding anhydrous xylene to a high-pressure reactor; (2) sequentially adding 1,3- Butadiene, perfluorohexyl ethyl acrylate, and vinyltrimethoxysilane were stirred at room temperature; then tert-dodecyl mercaptan was added, and stirring continued; the system was heated to 65℃, and tert-butyl peroxypentanoate was added; the reaction temperature was controlled at 65-70℃, the stirring speed at 200 r / min, a slight positive pressure of 0.05-0.08 MPa was maintained inside the reactor, and nitrogen was continuously used for protection, and polymerization was carried out at this temperature for 7 hours; samples were taken after 4 hours of polymerization to test the solid content, which reached 48-52%. Continue the reaction at the specified temperature until the endpoint is reached; raise the temperature to 75℃ and maintain the temperature for 1.5 hours; after the maturation is completed, lower the temperature to 55-60℃ and start vacuum distillation; after no distillate flows out, purge with 99.99% pure nitrogen to break the vacuum; cool the system to 40℃ and filter at 200℃ to obtain the product; wherein, the mass ratio of 1,3-butadiene, perfluorohexyl ethyl acrylate, vinyltrimethoxysilane, anhydrous xylene, tert-butyl peroxypentanoate and tert-dodecyl mercaptan is 68:14:4:85:1:0.4; The preparation of the core-shell powder includes: adding basalt nanocrystals with a diameter of 30-60 nm and a length of 300-500 nm, anhydrous ethanol, and deionized water at a mass ratio of 1:9:1; adding 7 wt% (by weight) of modified methacryloyloxy POSS to the basalt nanocrystals; reacting at a constant temperature of 70-75℃ and 300 r / min for 150 min; centrifuging, washing, and vacuum drying to obtain the modified grafted whiskers; melting a low-temperature fluorocarbon wax at 65-70℃, adding the modified grafted whiskers, shearing at 3000-4000 r / min for 20-30 min, cooling under a nitrogen-sealed atmosphere, and pulverizing through a 1000-mesh sieve to obtain the core-shell powder; the preparation of the modified methacryloyloxy POSS includes: mixing methacryloyloxy cage-type octameric silsesquioxane, 2-aminobenzothiazole, and anhydrous ethanol at a molar ratio of 1:1.2:15, and adding 1.5% (by weight) of the mixture to the total system mass. Glacial acetic acid was used as a catalyst; after dissolving by stirring at room temperature, the temperature was raised to 55-60℃ and refluxed for 4.5 hours. After cooling and standing, crystals were precipitated, filtered, washed multiple times with anhydrous ethanol, and dried under vacuum at 55℃ for 5 hours to obtain the final product.

[0011] Furthermore, in a preferred embodiment of the present invention, in the preparation of vinyl-terminated fluorinated polybutadiene resin, in step (1), after adding anhydrous xylene, the reactor is sealed and nitrogen is continuously replaced three times. Each replacement pressure is 0.2 MPa, and the reactor is allowed to stand for 5 minutes before being vented, so that the oxygen content in the reactor is controlled to be ≤20 ppm.

[0012] Furthermore, in a preferred embodiment of the present invention, in the preparation of vinyl-terminated fluorinated polybutadiene resin, in step (2), before feeding the material into the reactor, the stirring is turned on and the stirring speed is set to 180 r / min; after feeding the material into the reactor, the stirring is carried out for 30 min at room temperature of 25°C; after adding tert-dodecyl mercaptan, the stirring is continued for 15 min.

[0013] Furthermore, in a preferred embodiment of the present invention, the core-shell powder is prepared by centrifugation at 8500 r / min for 15 min, washing with ethanol three times, and vacuum drying at 55°C for 5 h.

[0014] Furthermore, in a preferred embodiment of the present invention, the wear-resistant additive is nano-α-alumina with a particle size of 30-80 nm.

[0015] Furthermore, in a preferred embodiment of the present invention, the light stabilizer comprises HALS944:UV329 in a mass ratio of 1:1.5.

[0016] Furthermore, in a preferred embodiment of the present invention, the leveling agent is a polyether-modified polysiloxane leveling agent.

[0017] Furthermore, in a preferred embodiment of the present invention, the environmentally friendly solvent includes ethyl acetate and methyl isobutyl ketone in a mass ratio of 6:4.

[0018] A method for preparing the above-mentioned wear-resistant coating for drone shells includes: (1) Hydrogenated bisphenol A epoxy resin is mixed with vinyl-terminated fluorinated polybutadiene resin and stirred at 65-70℃ and 200-300r / min for 65-74min to form a resin matrix; (2) First, add core-shell powder and aluminum borate nanofibers to the resin matrix for dispersion; after cooling to 25-30℃, add wear-resistant additives, polyetherimide micro powder, silane coupling agent KH-792, light stabilizer, leveling agent and environmentally friendly solvent, stir at low speed of 100-120r / min for 60-80min; filter with 250 mesh, let stand at room temperature for 50min to defoam and obtain the finished product.

[0019] Furthermore, in a preferred embodiment of the present invention, in step (2), the dispersion conditions are dispersion at a rotation speed of 2500-2700 r / min for 30-40 min.

[0020] The beneficial effects of the wear-resistant coating for drone shells and its preparation method provided by this invention are: (1) The wear-resistant coating for UAV shell provided by the present invention uses hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene resin to form an interpenetrating cross-linked network. The hydrogenated bisphenol A epoxy resin provides high hardness, high structural strength and excellent substrate adhesion, ensuring that the coating achieves extremely strong bonding force on various substrates such as carbon fiber, aluminum alloy and ABS. The vinyl-terminated fluorinated polybutadiene resin gives the coating excellent low-temperature toughness and aging resistance. The two work together to make the coating maintain good flexibility under extreme temperature cycling conditions, and it is not easy to crack, peel or fall off, which significantly improves the structural stability of UAV shell in low temperature, high altitude and complex environment. (2) The wear-resistant coating for UAV shells provided by the present invention uses a core-shell structure powder formed by modified POSS grafted basalt nanocrystals and low-temperature wetting fluorocarbon wax. The basalt nanocrystals form a three-dimensional rigid interwoven skeleton inside the coating, which greatly improves the coating hardness, scratch resistance and wind and sand erosion resistance, and significantly reduces wear and tear caused by long-term flight. The core-shell structure can effectively prevent filler agglomeration, improve dispersion uniformity, and enhance the bonding strength between filler and resin interface, which greatly improves the overall mechanical properties of the coating and significantly increases the wear life compared with traditional coatings. At the same time, the core-shell structure has a unique low-temperature self-wetting function. When the coating is subjected to impact, vibration and temperature stress and microcracks are generated, the repair component can automatically seep out and fill the crack area in the low-temperature environment, realizing rapid crack healing. This function can inhibit crack propagation from the root and avoid failure phenomena such as cracking, peeling and exposure of the substrate in the coating, which greatly improves the long-term reliability and service life of the UAV shell protective coating. (3) The wear-resistant coating for UAV shells provided by the present invention, through the modification of the POSS structure, constructs a stable ultraviolet absorption and free radical capture system inside the coating, and forms a dual weather protection with the help of a high-efficiency light stabilizer. It can effectively block strong ultraviolet radiation at high altitudes, inhibit resin degradation, discoloration and chalking, and make the coating maintain stable appearance, mechanical properties and adhesion under long-term aging conditions. Its weather resistance life is significantly better than that of conventional UAV coatings. At the same time, through the scientific compounding of components such as aluminum borate nanofibers, polyetherimide micro powder and wear-resistant fillers, a multi-level and multi-scale synergistic reinforcement system is formed, which further improves the impact resistance, structural strength and dimensional stability of the coating. The components have good compatibility and no antagonistic effect, and can form a highly dense continuous curing film, which effectively blocks the intrusion of moisture, dust and corrosive media, and provides all-round long-term protection for UAV shells. (4) The method for preparing wear-resistant coating for UAV shell provided by the present invention is mild and controllable, does not require high temperature and high pressure or special equipment, has a stable source of raw materials, and is suitable for large-scale production; the coating can be applied by conventional spraying, brushing and other methods, and can be cured quickly at room temperature, perfectly adapting to UAV composite materials, plastics, metals and other heat-sensitive substrates; after curing, the coating has stable and reliable comprehensive performance, which can fully meet the long-term protection needs of UAV in complex and harsh environments such as high altitude, field, sandstorm, low temperature and strong ultraviolet, greatly reducing maintenance costs and having extremely high engineering application value. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] The following is a detailed description of a wear-resistant coating for a drone shell and its preparation method provided by an embodiment of the present invention.

[0023] In the raw materials of the wear-resistant coating for drone shells provided in this embodiment of the invention, the hydrogenated bisphenol A epoxy resin is purchased from Hunan Servi New Material Technology Co., Ltd., model SH-3000; the aluminum borate nanofibers are purchased from Changsha Jingkang New Material Technology Co., Ltd., producing nano aluminum borate whiskers (high-purity coating grade); the polyetherimide micro powder is purchased from Saudi Basic Industries Corporation, model ULTEM™ PEI 1000P; the silane coupling agent is KH-792; and the nano α... Alumina was purchased from Nanjing Tianxing New Materials Co., Ltd., model TAP-A21; light stabilizer was purchased from Suqian Liansheng Technology Co., Ltd., a compound of light stabilizer 944 and UV-329; polyether-modified polysiloxane leveling agent was purchased from BYK Chemicals, Germany, model BYK-333; ethyl acetate and methyl isobutyl ketone were both industrial grade premium products; basalt nanocrystals were purchased from Shanghai Maclean Biochemical Technology Co., Ltd., item number B802359, with a diameter of 30-60nm, a length of 300-500nm, and a purity of not less than 99%.

[0024] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0025] Example 1 This embodiment provides a wear-resistant coating for drone shells, the raw materials of which, by weight, include: 40 parts of hydrogenated bisphenol A epoxy resin, 16 parts of vinyl-terminated fluorinated polybutadiene resin, 9 parts of core-shell powder, 3 parts of aluminum borate nanofibers with a diameter of 30 nm, 1.5 parts of polyetherimide micro powder, 0.8 parts of nano-α-alumina, 0.6 parts of silane coupling agent KH-792, 1.4 parts of light stabilizer (HALS944:UV329 in a mass ratio of 1:1.5), 0.4 parts of polyether-modified polysiloxane leveling agent, and 20 parts of environmentally friendly solvent (ethyl acetate and methyl isobutyl ketone in a mass ratio of 6:4). The preparation of vinyl-terminated fluorinated polybutadiene resin includes: (1) adding anhydrous xylene into a high-pressure reactor, sealing the reactor, and performing nitrogen purging three times consecutively, with a purging pressure of 0.2 MPa each time. After standing for 5 minutes, the reactor is vented to control the oxygen content in the reactor to ≤20 ppm; (2) starting the stirrer and setting the stirring speed to 180 r / min; adding 1,3-butadiene, perfluorohexyl ethyl acrylate, and vinyltrimethoxysilane into the reactor in sequence, and stirring for 30 minutes at room temperature (25°C); then adding tert-dodecyl mercaptan and continuing to stir for 15 minutes; raising the system temperature to 65°C and adding tert-butyl peroxypentanoate; controlling the reaction temperature to 68°C, the stirring speed to 200 r / min, maintaining a slight positive pressure of 0.06 MPa in the reactor, and continuous nitrogen protection, and polymerizing at a constant temperature for 7 hours; taking samples to detect the solid content after 4 hours of polymerization, and the solid content reaching 50%. The reaction was continued at the specified temperature until the endpoint was reached; the temperature was raised to 75°C and maintained for 1.5 hours; after aging, the temperature was lowered to 58°C and vacuum distillation was started; after no distillate flowed out, nitrogen gas with a purity of 99.99% was introduced to break the vacuum; the system was cooled to 40°C and filtered at 200°C to obtain the product; wherein, the mass ratio of 1,3-butadiene, perfluorohexyl ethyl acrylate, vinyltrimethoxysilane, anhydrous xylene, tert-butyl peroxypentanoate and tert-dodecyl mercaptan was 68:14:4:85:1:0.4; The preparation of the core-shell powder includes: basalt nanocrystals, anhydrous ethanol, and deionized water are added in a mass ratio of 1:9:1; 7 wt% of modified methacryloyloxy POSS is added to the basalt nanocrystals; the mixture is reacted at a constant temperature of 72℃ and 300 r / min for 150 min; centrifuged at 8500 r / min for 15 min; washed three times with ethanol; and vacuum dried at 55℃ for 5 h to obtain the modified grafted whiskers; 68℃ low-temperature fluorocarbon wax is melted, added to the modified grafted whiskers, sheared at 3500 r / min for 25 min, cooled in a nitrogen-sealed atmosphere, and pulverized through a 1000-mesh sieve to obtain the core-shell powder; the preparation of modified methacryloyloxy POSS includes: mixing methacryloyloxy cage-type octameric silsesquioxane, 2-aminobenzothiazole, and anhydrous ethanol in a molar ratio of 1:1.2:15, and adding 1.5% of the total mass of the system. Glacial acetic acid was used as a catalyst; after dissolving by stirring at room temperature, the temperature was raised to 58°C and refluxed for 4.5 hours. After cooling and standing, crystals were precipitated, filtered, washed multiple times with anhydrous ethanol, and dried under vacuum at 55°C for 5 hours to obtain the final product.

[0026] This embodiment also provides a method for preparing the above-mentioned wear-resistant coating for drone shells, comprising: (1) Hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene resin are mixed and stirred at 68°C and 250 r / min for 70 min to form a resin matrix; (2) First, add core-shell powder and aluminum borate nanofibers to the resin matrix and disperse at 2600 r / min for 35 min; after cooling to 28℃, add nano α-alumina, polyetherimide micro powder, silane coupling agent KH-792, light stabilizer, leveling agent and environmentally friendly solvent, stir at 110 r / min for 70 min; filter with 250 mesh, let stand at room temperature for 50 min to defoam and obtain the finished product.

[0027] Example 2 This embodiment provides a wear-resistant coating for drone shells and its preparation method, which differs from Embodiment 1 in that: its raw materials, by weight, include: 35 parts of hydrogenated bisphenol A epoxy resin, 18 parts of vinyl-terminated fluorinated polybutadiene resin, 7 parts of core-shell powder, 4 parts of aluminum borate nanofibers, 1 part of polyetherimide micro powder, 1.0 part of nano-α-alumina, 0.4 parts of silane coupling agent KH-792, 1.6 parts of light stabilizer (HALS944:UV329 in a mass ratio of 1:1.5), 0.2 parts of polyether-modified polysiloxane leveling agent, and 22 parts of environmentally friendly solvent (ethyl acetate and methyl isobutyl ketone in a mass ratio of 6:4).

[0028] Example 3 This embodiment provides a wear-resistant coating for drone shells and its preparation method, which differs from Embodiment 1 in that: the raw materials, by weight, include 42 parts of hydrogenated bisphenol A epoxy resin, 12 parts of vinyl-terminated fluorinated polybutadiene resin, 11 parts of core-shell powder, 2 parts of aluminum borate nanofibers, 2 parts of polyetherimide micro powder, 0.6 parts of nano-α-alumina, 0.8 parts of silane coupling agent KH-792, 1.2 parts of light stabilizer (HALS944:UV329 in a mass ratio of 1:1.5), 0.5 parts of polyether-modified polysiloxane leveling agent, and 16 parts of environmentally friendly solvent (ethyl acetate and methyl isobutyl ketone in a mass ratio of 6:4).

[0029] Example 4 This embodiment provides a wear-resistant coating for the shell of a drone and its preparation method. The difference from Embodiment 1 is that the preparation method includes: (1) mixing hydrogenated bisphenol A epoxy resin with vinyl-terminated fluorinated polybutadiene resin and stirring at 65°C and 300r / min for 65min to form a resin matrix; (2) first adding core-shell powder and aluminum borate nanofibers to the resin matrix and dispersing at 2700r / min for 30min; after cooling to 30°C, adding nano α-alumina, polyetherimide micro powder, silane coupling agent KH-792, light stabilizer, polyether-modified polysiloxane leveling agent and environmentally friendly solvent, stirring at 100r / min for 80min; filtering with 250 mesh and letting stand at room temperature for 50min to defoam to obtain the finished product.

[0030] Example 5 This embodiment provides a wear-resistant coating for the shell of a drone and its preparation method. The difference from Embodiment 1 is that the preparation method includes: (1) mixing hydrogenated bisphenol A epoxy resin with vinyl-terminated fluorinated polybutadiene resin and stirring at 70°C and 200r / min for 74min to form a resin matrix; (2) first adding core-shell powder and aluminum borate nanofibers to the resin matrix and dispersing at 2500r / min for 40min; after cooling to 25°C, adding nano α-alumina, polyetherimide micro powder, silane coupling agent KH-792, light stabilizer, polyether-modified polysiloxane leveling agent and environmentally friendly solvent, stirring at 120r / min for 60min; filtering with 250 mesh and letting stand at room temperature for 50min to defoam to obtain the finished product.

[0031] Comparative Example 1 This comparative example provides an abrasion-resistant coating for drone shells, the raw materials of which, by weight, include: 53 parts of silicone polyurethane resin (Guangzhou Silok, model Dolphin1099R), 8 parts of fumed nano-SiO2 (Germany Evonik, model AEROSIL R972), 3 parts of hexagonal boron nitride (hBN) (France Saint-Gobain, model HPF06), 2 parts of polyetherimide micro powder, 0.6 parts of silane coupling agent KH-792, 1.4 parts of light stabilizer (HALS944:UV329 at a mass ratio of 1:1.5), 0.3 parts of polyether-modified polysiloxane leveling agent, and 18 parts of environmentally friendly solvent.

[0032] This comparative example also provides a method for preparing the above-mentioned wear-resistant coating for drone shells, comprising: adding organosilicon polyurethane resin and 60% of the total amount of compounded solvent to a dispersion vessel at room temperature (25°C), stirring at 350 r / min for 50 min to obtain a resin liquid; impregnating the powder with fumed nano-SiO2, hBN, polyetherimide micro powder and silane coupling agent KH-792 with an environmentally friendly solvent, stirring and premixing at room temperature for 15 min to obtain a premixed filler slurry; transferring the premixed filler slurry into the resin liquid, dispersing at high speed (1600 r / min) for 35 min; cooling the system to 30-35°C, adding a light stabilizer and a polyether-modified polysiloxane leveling agent sequentially at a low speed (350 r / min), stirring for 45 min; adjusting the viscosity with the remaining environmentally friendly solvent, filtering through a 250-mesh filter, allowing to stand at room temperature for 50 min to defoam, and then discharging the material.

[0033] Comparative Example 2 This comparative example provides a wear-resistant coating for drone shells and its preparation method. The difference from Example 1 is that the core-shell powder in the raw materials is replaced by basalt nanocrystals. In the preparation method: In step (2), basalt nanocrystals, aluminum borate nanofibers and nano α-alumina are mixed, and silane coupling agent KH-792 is diluted with a small amount of environmentally friendly solvent and sprayed to wet the powder. The mixture is premixed at room temperature for 20 min to obtain pretreated filler. The pretreated filler and polyetherimide micro powder are added to the resin matrix and dispersed at high speed of 1650 r / min for 35 min. The temperature is lowered to 35℃, and light stabilizer and leveling agent are added at low speed of 350 r / min. The mixture is stirred continuously for 50 min. Environmentally friendly solvent is added and stirred evenly. The mixture is filtered through 250 mesh and defoamed at room temperature for 50 min to prepare the sample.

[0034] Comparative Example 3 This comparative example provides a wear-resistant coating for drone shells and its preparation method. The difference from Example 1 is that the vinyl-terminated fluorinated polybutadiene resin in the raw materials is replaced with polybutadiene resin (CrayValley, USA, model Ricon130). In the preparation method: In step (1), hydrogenated bisphenol A epoxy resin and polybutadiene resin are mixed at 68°C and 380 r / min for 70 min to prepare the resin matrix; In step (2), the core-shell powder, aluminum borate nanofibers, and nano-α-alumina are mixed, and the polyetherimide micro powder is pre-diluted with a small amount of environmentally friendly solvent KH-792 and sprayed to wet the powder. The mixture is pre-mixed at room temperature for 20 minutes to obtain the pretreated filler. The pretreated filler is added to the resin matrix and dispersed at high speed of 1600 r / min for 35 minutes. The temperature is lowered to 35℃, and the light stabilizer and leveling agent are added at low speed of 350 r / min. The mixture is stirred continuously for 50 minutes. The environmentally friendly solvent is added and stirred evenly. The mixture is filtered through a 250 mesh and allowed to stand at room temperature for 50 minutes to defoam, thus obtaining the finished product.

[0035] Comparative Example 4: This comparative example provides a wear-resistant coating for drone shells and its preparation method. The difference from Example 1 is that the core-shell powder in the raw materials is a composite powder obtained by simply dry mixing three powders: aminobenzothiazole modified POSS powder, basalt nanocrystals, and low-temperature fluorocarbon wax, which replace the core-shell powder by equal mass.

[0036] In the preparation method: In step (2), the composite powder, aluminum borate nanofibers, and nano α-alumina are mixed, and the polyetherimide micro powder is pre-diluted with a small amount of environmentally friendly solvent and sprayed to wet the powder. The mixture is pre-mixed at room temperature for 20 min to obtain the pretreated filler. The pretreated filler is added to the resin matrix and dispersed at high speed of 1600 r / min for 35 min. The temperature is lowered to 35℃, and the light stabilizer and leveling agent are added at low speed of 350 r / min. The mixture is stirred continuously for 50 min. The environmentally friendly solvent is added and stirred evenly. The mixture is filtered through 250 mesh and allowed to stand at room temperature for 50 min to defoam to obtain the finished product.

[0037] Comparative Example 5 This comparative example provides a wear-resistant coating for drone shells and its preparation method, which differs from Example 1 in that: its raw materials, by weight, include 30 parts of hydrogenated bisphenol A epoxy resin, 20 parts of vinyl-terminated fluorinated polybutadiene resin, 6 parts of core-shell powder, 5 parts of aluminum borate nanofibers, 0.5 parts of polyetherimide micro powder, 1.2 parts of nano-α-alumina, 0.3 parts of silane coupling agent KH-792, 1.8 parts of light stabilizer (HALS944:UV329 in a mass ratio of 1:1), 0.1 parts of polyether-modified polysiloxane leveling agent, and 25 parts of environmentally friendly solvent (ethyl acetate and methyl isobutyl ketone in a mass ratio of 5:5).

[0038] Comparative Example 6 This comparative example provides a wear-resistant coating for the shell of a drone and its preparation method. The difference from Example 1 is that the preparation method includes: (1) mixing hydrogenated bisphenol A epoxy resin with vinyl-terminated fluorinated polybutadiene resin and stirring at 60°C and 350 r / min for 60 min to form a resin matrix; (2) first adding core-shell powder and aluminum borate nanofibers to the resin matrix and dispersing at 2800 r / min for 25 min; after cooling to 35°C, adding nano α-alumina, polyetherimide micro powder, silane coupling agent KH-792, light stabilizer, polyether-modified polysiloxane leveling agent and environmentally friendly solvent, stirring at 90 r / min for 90 min; filtering with 250 mesh and letting stand at room temperature for 50 min to defoam to obtain the finished product.

[0039] Experimental Example 1 The wear-resistant coatings prepared in Examples 1-5 and Comparative Examples 1-6 were tested separately. They were sprayed onto commonly used aviation aluminum alloy substrates for UAVs, with a dry film thickness of 40 μm. After curing at room temperature for 24 hours, the performance was tested according to national standards. The test indicators included: pencil hardness, resistance to wind and sand erosion, water contact angle, 24-hour microcrack self-healing rate, appearance after 3000 hours of UV aging, number of high and low temperature alternating cycles, and cross-cut adhesion.

[0040] The indicator testing standards are as follows: Pencil hardness: Tested according to the method specified in GB / T 6739-2022; Resistance to wind and sand erosion: The coating industry directional sandblasting simulation test was adopted, using 80-120 mesh quartz sand and 0.3MPa wind pressure, and the number of erosion cycles corresponding to the first damage of the coating was counted. Water contact angle: Measured using a contact angle tester at 23°C and 50% relative humidity, in accordance with ISO 21148 and ASTM D7334 standards. 24h Low-Temperature Microcrack Self-Repair Rate: Pre-fabricated microcracks of fixed specifications were placed at -10℃ for 24 hours. The change in crack area was measured by metallographic microscope and the repair rate was calculated. UV aging performance: UVA-340 fluorescent UV aging test was carried out according to GB / T 16422.3-2014, with a cumulative aging of 3000h, and the appearance of the coating was evaluated according to GB / T 1766-2008; High and low temperature cycling performance: Temperature cycling test was carried out according to GJB 150.4A-2009, alternating between -45℃ and 85℃, and the critical number of cycles before the coating cracked and peeled off was recorded; Cross-grid adhesion: According to GB / T 9286-1998, the tape is applied and peeled off quickly at 90° after being crisscrossed with a 1mm grid, and then rated.

[0041] The test results are shown in Table 1: Table 1 As shown in Table 1, in Examples 1-5, hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene form an interpenetrating cross-linked network. The core-shell powder and reinforcing fillers such as aluminum borate and nano-alumina produce a synergistic effect, and the overall performance of the coating is significantly higher than that of the comparative example.

[0042] Comparative Example 3 replaced the vinyl-terminated fluorinated polybutadiene with ordinary polybutadiene. In the original system, the fluorinated vinyl-terminated polybutadiene could chemically bond with epoxy to form an interpenetrating network, possessing the synergistic advantages of low surface energy, high toughness at low temperatures, and resistance to UV aging. After replacing the fluorinated ordinary polybutadiene, the two resins only physically mixed and could not effectively crosslink, resulting in a significant loss of the synergistic effect between the two resins. The comparative data showed that Comparative Example 3 exhibited significant deterioration in wear resistance, self-healing rate, resistance to high and low temperature cycles, and resistance to UV aging, with obvious yellowing and microcracks appearing, and the adhesion dropping from grade 0 to grade 1. This indicates that the vinyl-terminated fluorination modification is the key structure for achieving the synergistic effect of the two resins.

[0043] Comparative Example 2 replaced ordinary basalt whiskers with integrated core-shell powder; Comparative Example 4 involved simple physical blending of modified POSS, basalt nanocrystals, and fluorocarbon wax, without a core-shell coating structure. Experimental data show that the integrated core-shell structure has significantly better overall performance than the sum of the performance of the three simple blends. The core-shell configuration is key to achieving synergistic effects of rigid reinforcement, interfacial bonding, and low-temperature self-healing.

[0044] Comparative Example 1 is a commercially available silicone polyurethane coating. Various fillers are only physically filled, without a chemical cross-linking synergistic system, low-temperature self-healing components, and no multi-component synergistic gain, resulting in the worst overall performance.

[0045] The raw material ratio of Comparative Example 5 and the preparation process of Comparative Example 6 both exceed the scope of protection of the claims. The component ratio is unbalanced, the filler dispersion and resin crosslinking environment are destroyed, the synergistic effect between components decreases, and the performance is lower than that of the examples.

[0046] In summary, the wear-resistant coating for UAV shells and its preparation method provided by this invention form a stable interpenetrating cross-linked network through hydrogenated bisphenol A epoxy resin and vinyl-terminated fluorinated polybutadiene resin. Combined with specially formulated core-shell structured powder fillers, aluminum borate nanofibers, polyetherimide micro powder, and wear-resistant and weather-resistant additives, an integrated protective system is constructed that combines high wear resistance, resistance to wind and sand erosion, low-temperature crack resistance, microcrack self-repair, strong UV aging resistance, and high adhesion. This system can significantly improve the long-term service stability and service life of UAV shells in complex and harsh environments such as high altitude, wind and sand, high and low temperature alternation, and strong UV radiation.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wear-resistant coating for drone shells, characterized in that: The raw materials, by weight, include: 35-42 parts of hydrogenated bisphenol A epoxy resin with an epoxy equivalent of 180-220 g / eq, 12-18 parts of vinyl-terminated fluorinated polybutadiene resin, 7-11 parts of core-shell powder, 2-4 parts of aluminum borate nanofibers with a diameter of 20-40 nm, 1-2 parts of polyetherimide micropowder with a particle size of 500-800 nm, 0.6-1.0 parts of wear-resistant additive, 0.4-0.8 parts of silane coupling agent KH-792, 1.2-1.6 parts of light stabilizer, 0.2-0.5 parts of leveling agent, and 16-22 parts of environmentally friendly solvent; The preparation of the vinyl-terminated fluorinated polybutadiene resin includes: (1) Add anhydrous xylene to the high-pressure reactor; (2) Add 1,3-butadiene, perfluorohexyl ethyl acrylate, and vinyltrimethoxysilane to the reactor in sequence, and stir at room temperature; then add tert-dodecyl mercaptan and continue stirring; raise the system temperature to 65°C and add tert-butyl peroxypentanoate; control the reaction temperature at 65-70°C, the stirring speed at 200 r / min, maintain a slight positive pressure of 0.05-0.08 MPa in the reactor, and continuously protect with nitrogen, and polymerize at a constant temperature for 7 hours; take a sample to detect the solid content after 4 hours of polymerization, and the solid content reaches 48-52%. Continue the reaction at the specified temperature until the endpoint is reached; raise the temperature to 75℃ and maintain the temperature for 1.5 hours; after the maturation is completed, lower the temperature to 55-60℃ and start vacuum distillation; after no distillate flows out, purge with 99.99% pure nitrogen to break the vacuum; cool the system to 40℃ and filter at 200℃ to obtain the product; wherein, the mass ratio of 1,3-butadiene, perfluorohexyl ethyl acrylate, vinyltrimethoxysilane, anhydrous xylene, tert-butyl peroxypentanoate and tert-dodecyl mercaptan is 68:14:4:85:1:0.4; The preparation of the core-shell powder includes: Basalt nanocrystals with a diameter of 30-60 nm and a length of 300-500 nm, anhydrous ethanol, and deionized water were added at a mass ratio of 1:9:

1. 7 wt% of modified methacryloyloxy POSS was added to the basalt nanocrystals. The mixture was reacted at a constant temperature of 70-75°C and 300 rpm for 150 min. After centrifugation, washing, and vacuum drying, the modified grafted whiskers were obtained. Low-temperature fluorocarbon wax was melted at 65-70°C, and the modified grafted whiskers were added. The mixture was sheared at 3000-4000 rpm for 20-30 min, cooled in a nitrogen-sealed atmosphere, and pulverized through a 1000-mesh sieve to obtain the core-shell powder. The preparation of the modified methacryloyloxy POSS includes: mixing methacryloyloxy cage-type octameric silsesquioxane, 2-aminobenzothiazole, and anhydrous ethanol in a molar ratio of 1:1.2:15, adding 1.5% of glacial acetic acid as a catalyst; stirring and dissolving at room temperature, then heating to 55-60℃ and refluxing for 4.5 h, cooling and allowing to stand to crystallize, filtering, washing repeatedly with anhydrous ethanol, and vacuum drying at 55℃ for 5 h to obtain the product.

2. The wear-resistant coating for drone shells according to claim 1, characterized in that: In the preparation of the vinyl-terminated fluorinated polybutadiene resin, in step (1), after adding the anhydrous xylene, the reactor is sealed and nitrogen is continuously replaced 3 times. Each replacement pressure is 0.2 MPa, and the reactor is left to stand for 5 minutes before being vented to control the oxygen content in the reactor to ≤20 ppm.

3. The wear-resistant coating for drone shells according to claim 1, characterized in that: In the preparation of the vinyl-terminated fluorinated polybutadiene resin, in step (2), before feeding the material into the reactor, the stirring is turned on and the stirring speed is set to 180 r / min; after feeding the material into the reactor, the stirring is carried out for 30 min at room temperature of 25℃; after adding the tert-dodecyl mercaptan, the stirring is continued for 15 min.

4. The wear-resistant coating for drone shells according to claim 1, characterized in that: In the preparation of the core-shell powder, the powder is centrifuged at 8500 r / min for 15 min, washed three times with ethanol, and vacuum dried at 55℃ for 5 h to obtain the final product.

5. The wear-resistant coating for drone shells according to claim 1, characterized in that: The wear-resistant additive is made of nano-α-alumina with a particle size of 30-80 nm.

6. The wear-resistant coating for a drone shell according to claim 1, characterized in that: The light stabilizer comprises HALS944:UV329 in a mass ratio of 1:1.

5.

7. The wear-resistant coating for drone shells according to claim 1, characterized in that: The leveling agent used is a polyether-modified polysiloxane leveling agent.

8. The wear-resistant coating for drone shells according to claim 1, characterized in that: The environmentally friendly solvents include ethyl acetate and methyl isobutyl ketone in a mass ratio of 6:

4.

9. A method for preparing an abrasion-resistant coating for a drone shell according to any one of claims 1-8, characterized in that: include: (1) The hydrogenated bisphenol A epoxy resin and the vinyl-terminated fluorinated polybutadiene resin are mixed and stirred at 65-70°C and 200-300 r / min for 65-74 min to form a resin matrix; (2) First, add the core-shell powder and the aluminum borate nanofibers to the resin matrix for dispersion; after cooling to 25-30℃, add the wear-resistant additive, the polyetherimide micro powder, the silane coupling agent KH-792, the light stabilizer, the leveling agent and the environmentally friendly solvent, stir at low speed of 100-120r / min for 60-80min; filter with 250 mesh, and let stand at room temperature for 50min to defoam to obtain the finished product.

10. The method for preparing the wear-resistant coating for a drone shell according to claim 9, characterized in that: In step (2), the dispersion conditions are to disperse at a rotation speed of 2500-2700 r / min for 30-40 min.

Images