A coating for a wind turbine blade and a method of making the same

Abstract

This application relates to a coating for wind turbine blades and its preparation method, belonging to the field of coating technology. The coating is a three-layer composite structure, comprising a bottom layer, an intermediate layer, and an outer layer from the wind turbine blade substrate outwards. The bottom layer is a rare earth-reinforced thermal insulation anchoring layer, whose raw material components include: hydroxyl-terminated polydimethylsiloxane, polyurethane prepolymer, modified nano-cerium oxide, curing agent, solvent, and defoamer. The intermediate layer is a phase change energy storage LIPN buffer layer, whose raw material components include: modified fluororesin-siloxane LIPN emulsion, modified PCM microcapsules, soft-core hard-shell IPN particles, leveling agent, and film-forming aid. The outer layer is a rare earth-induced self-assembled superhydrophobic layer, whose raw material components include: low surface energy fluorosilicone resin, long-chain fluoroalkyl-modified nano-lanthanum oxide, isocyanate curing agent, hydrophobic nano-silica, and solvent. It possesses a protective effect integrating high adhesion, elastic buffering, phase change thermal storage, and self-healing superhydrophobic functions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating, in particular to a coating for wind power blades and a preparation method thereof. BACKGROUND

[0002] As a core component of global clean energy strategy, the installed capacity of wind power is growing at an astonishing speed. Wind power blades, as the key components for capturing wind energy, are exposed to complex natural environments for a long time, facing severe survival challenges. In particular, in high-latitude, high-altitude and low-temperature humid areas, wind power blades are prone to icing in winter. Blade icing not only changes the aerodynamic shape of the blade, leading to a decrease in lift and an increase in resistance, which seriously reduces the power generation efficiency (annual power generation loss can reach 10-20%), but also causes unbalanced blade load, inducing severe vibration of the unit, and even causing catastrophic accidents such as blade fracture and tower collapse. Therefore, developing efficient and durable anti-icing technology has become an urgent need to ensure the safe and stable operation of wind turbines in extreme weather conditions.

[0003] The existing wind power blade anti-icing technology mainly includes mechanical deicing, thermal deicing and passive coating anti-icing. Among them, mechanical deicing and thermal deicing (such as electric heating, hot air flow) have direct deicing effect, but have problems such as high energy consumption, complex system, high maintenance cost and lightning hazard. In contrast, passive anti-icing coating is concerned due to its low energy consumption and wide applicability. Current commercial anti-icing coatings mainly rely on a single superhydrophobic principle (such as fluorosilicone resin, lotus effect coating), trying to reduce the surface energy to make supercooled water droplets roll off before freezing.

[0004] However, the existing wind power blade anti-icing coating has many pain points in actual extreme working conditions, and it is difficult to meet the long-term operation requirements: first, the single superhydrophobic coating lacks active intervention mechanism, and when facing high-adhesion rime, graupel and mixed ice, it often appears the failure phenomenon of "hydrophobic but not icephobic", and once the ice layer is formed, the interfacial anchoring force is large and it is difficult to fall off; second, the tip line speed of the wind turbine blade is very high (can reach more than 80 m / s), and the rain erosion and sand erosion caused by high-speed rotation easily damage the micro-nano structure on the surface of the coating, leading to rapid decay of hydrophobicity; third, due to the difference in thermal expansion coefficient and elastic modulus between the blade composite and the coating, under the long-term vibration fatigue and alternating cold and hot impact, the coating is prone to micro-cracks, peeling and even delamination; finally, the traditional anti-icing coating design often ignores the thermodynamic blocking at the initial icing stage and the stress buffering at the impact moment, and lacks systematic protection for the whole process of "frozen rain impact - condensation heat release - interfacial anchoring".

[0005] Therefore, it is of great significance to develop a new wind turbine blade protection system that integrates high-strength adhesion, elastic buffering, phase change heat storage and self-healing superhydrophobic functions, so as to solve the technical bottleneck of low anti-icing efficiency and poor durability of existing technologies in multiple extreme environments. Summary of the Invention

[0006] This application provides a coating for wind turbine blades and its preparation method, which has a protective effect that integrates high adhesion, elastic buffering, phase change heat storage and self-healing superhydrophobicity.

[0007] Firstly, the coating for wind turbine blades provided in this application adopts the following technical solution: A coating for wind turbine blades, the coating having a three-layer composite structure, comprising a bottom layer, a middle layer and an outer layer from the wind turbine blade substrate outwards; The bottom layer is a rare earth reinforced thermal insulation anchoring layer, and its raw material components include, by weight: 30-40 parts of hydroxyl-terminated polydimethylsiloxane, 40-50 parts of polyurethane prepolymer, 5-10 parts of modified nano-cerium oxide, 5-8 parts of curing agent, 20-30 parts of solvent, and 0.5-1 parts of defoamer. The intermediate layer is a phase change energy storage LIPN buffer layer, and its raw material components include, by weight: 100 parts of modified fluororesin-siloxane LIPN emulsion, 15-25 parts of modified PCM microcapsules, 10-15 parts of soft core hard shell IPN granules, 0.5-1 parts of leveling agent, and 3-5 parts of film-forming aid. The outer layer is a rare earth-induced self-assembled superhydrophobic layer, and its raw material components include, by weight: 100 parts of low surface energy fluorosilicone resin, 10-15 parts of long-chain fluoroalkyl modified nano lanthanum oxide, 10-12 parts of isocyanate curing agent, 2-4 parts of hydrophobic nano silica, and 30-40 parts of solvent.

[0008] By adopting the above technical solution, a three-layer composite structure consisting of a bottom layer for thermal insulation and anchoring, a middle layer for thermal-mechanical dynamic buffering, and an outer layer for self-assembly and superhydrophobicity is employed. Through specific component combinations, excellent comprehensive protective performance is achieved. Specifically, the bottom layer, through the combination of hydroxyl-terminated polydimethylsiloxane and polyurethane prepolymer, leverages the high adhesion strength of polyurethane and the flexibility of polydimethylsiloxane. Enhanced by the chemical bonding of modified nano-cerium oxide, this not only improves the mechanical interlocking and adhesion between the coating and the wind turbine blade substrate but also utilizes the unique lattice structure of nano-cerium oxide to scatter phonons, constructing an effective thermal barrier and reducing heat loss to the substrate.

[0009] The intermediate layer uses a modified fluoropolymer-siloxane LIPN emulsion as the matrix, combined with modified PCM microcapsules and soft-core hard-shell IPN particles. By utilizing the bicontinuous phase structure of the LIPN interpenetrating network to synergize the release of latent heat of phase change of the microcapsules and the elastic deformation of the particles, it is possible to delay freezing through phase change exothermic reaction in low-temperature environments and buffer the impact force through high elastic energy absorption during freezing rain impacts. At the same time, the dynamic bonds on the surface of the microcapsules endow the coating with self-healing ability for microcracks.

[0010] The outer layer utilizes the directional arrangement and induced self-assembly of long-chain fluoroalkyl modified nano-lanthanum oxide in low surface energy fluorosilicone resin to construct a high-hardness, wear-resistant superhydrophobic micro-nano structure. This reduces the adhesion of ice water while protecting the inner structure, thus enabling the coating to simultaneously possess high superhydrophobicity, excellent dynamic impact resistance, self-healing long-term durability, and strong adhesion to the substrate.

[0011] Optionally, the preparation method of the modified nano-cerium oxide includes the following steps: S1. Disperse 10-15 parts by weight of nano-cerium oxide in 100-150 parts by weight of anhydrous ethanol and ultrasonically disperse for 20-40 minutes. S2. Add 1-2 parts by weight of KH-560 silane coupling agent and adjust the pH value to 4-5 with acid; S3. Stir the reaction in a water bath at 55-65℃ for 5-7 hours; after the reaction is completed, centrifuge and wash with ethanol, then vacuum dry at 70-90℃ for 10-14 hours to obtain the modified nano-cerium oxide.

[0012] By adopting the above technical solution, the process of hydrolyzing and condensing KH-560 silane coupling agent in an acidic alcohol-water system is used. By controlling the ultrasonic dispersion time and reaction temperature, the aggregation of nanoparticles is suppressed, and epoxy groups are successfully grafted onto the cerium oxide surface.

[0013] This preparation process not only retains the thermal insulation phonon scattering characteristics of cerium oxide itself, but also introduces highly active epoxy groups, enabling it to participate in the curing reaction of the underlying polyurethane / polydimethylsiloxane system. This transforms physical filling into chemical bonding, improving the dispersion stability and interfacial bonding strength of the filler in the resin matrix, thereby enhancing the mechanical strength and thermal insulation performance of the underlying layer.

[0014] Optionally, the preparation method of the modified fluoropolymer-siloxane LIPN emulsion includes the following steps: S1. Pre-emulsification and seed polymerization: 18-22 parts by weight of hexafluorobutyl acrylate, 28-32 parts by weight of methyl methacrylate, 1-3 parts by weight of vinyltriethoxysilane, 140-160 parts by weight of deionized water, and 0.8-1.2 parts by weight of sodium dodecylbenzenesulfonate are mixed and pre-emulsified; the temperature is raised to 70-80℃, and 0.2-0.4 parts by weight of potassium persulfate aqueous solution is added dropwise, and the reaction is carried out for 3-5 hours to obtain fluoropropylene seed emulsion; S2, Interpenetrating network construction: Add a mixture of 35-45 parts by weight of octamethylcyclotetrasiloxane and 0.5-1 parts by weight of dodecylbenzenesulfonic acid to the seed emulsion obtained in S1, and react at 75-85℃ for 5-7 hours. S3. Post-treatment: Cool to room temperature, adjust pH to 7 with alkali, and filter to obtain the modified fluororesin-siloxane LIPN emulsion.

[0015] By adopting the above technical solution, a stepwise seed emulsion polymerization method was used to first synthesize fluorinated acrylate hard-core seeds, and then add organosilicon soft monomers for swelling polymerization. By controlling the monomer dropping rate and reaction temperature, the polysiloxane segments were successfully induced to interpenetrate and grow in the fluorinated polymer network, thus constructing an interpenetrating polymer network structure with microphase separation but uniformity.

[0016] This preparation process ensures that the surface enrichment characteristics of fluorine and the bulk flexibility of organosilicon are preserved at the same time, solving the problem of easy delamination in the simple blending of traditional fluorosilicone resins. This results in the synthesized emulsion having excellent weather resistance and hardness after curing, as well as high elasticity to adapt to the volume expansion of microcapsules and external impacts, providing a key matrix material for the intermediate layer that combines anti-icing and impact resistance.

[0017] Optionally, the preparation method of the modified PCM microcapsules includes the following steps: S1. Microencapsulation: Using n-octadecane as the core material and tetraethyl orthosilicate as the wall material precursor, silica-coated n-octadecane microcapsules were prepared by reacting under acidic conditions via a sol-gel method for 6-10 hours. S2, Surface functionalization: The microcapsules obtained in S1 are dispersed in an organic solvent, and 5-10% of furan-modified silane relative to the mass of the microcapsules is added. The reaction is carried out at 75-85℃ for 10-14 hours to graft furan groups onto the surface of the microcapsules. S3. Dynamic bond construction: Add a bismaleimide crosslinking agent with a molar ratio of 1:1 relative to furan-modified silane to the S2 reaction system, react at 55-65℃ for 2-4 h, and obtain the modified PCM microcapsules after drying.

[0018] By adopting the above technical solution, combining sol-gel microencapsulation technology with surface dynamic covalent chemical modification, a thermally reversible Diels-Alder dynamic bond network was successfully constructed on the surface of the microcapsule by first constructing a dense silica shell on the outside of the phase change core material, then grafting furan groups and crosslinking with bismaleimide.

[0019] This preparation process not only effectively encapsulates the phase change material to prevent leakage and ensures the stability of the heat storage function, but more importantly, it enables the microcapsule shell to have the ability to break and recombine in response to thermal stimuli. As a result, when the coating is damaged by microcracks, the microcapsules can act as active repair points to prevent crack propagation through chemical healing of dynamic bonds, giving the coating unique self-healing properties.

[0020] Optionally, the preparation method of the soft-core, hard-shell IPN colloidal particles includes the following steps: S1. Soft core synthesis: 55-65 parts by weight of butyl acrylate, 0.3-0.6 parts by weight of divinylbenzene, 0.5-1 parts by weight of emulsifier and 0.1-0.3 parts by weight of initiator are added to the reactor and reacted at 65-75℃ for 2-4 hours to form a cross-linked polybutyl acrylate soft core emulsion. S2, Hard shell coating: Add a mixture of 35-45 parts by weight of styrene, 0.3-0.6 parts by weight of divinylbenzene and 0.1-0.3 parts by weight of initiator to the soft core emulsion obtained in S1, and continue to react at the same temperature for 3-5 hours. After demulsification and drying, the soft core hard shell IPN particles are obtained.

[0021] By adopting the above technical solution and using an ordered multi-stage emulsion polymerization process, the polymerization sequence and crosslinking degree of the soft monomer butyl acrylate and the hard monomer styrene were controlled, and IPN particles with a clear core-shell structure were prepared.

[0022] This preparation method ensures that the soft core has sufficient volume and a low glass transition temperature to dissipate impact energy, while the hard shell provides the particles with good dispersibility and rigid support in the resin matrix, preventing particle deformation and collapse. As a result, the synthesized particles can not only improve the impact toughness of the coating, but also assist the coating in active ice breaking under vibration environment by constructing a modulus gradient.

[0023] Optionally, the preparation method of the long-chain fluoroalkyl-modified nano-lanthanum oxide includes the following steps: S1. Disperse nano-lanthanum oxide in a mixed solvent of ethanol and water, and add perfluorooctyltriethoxysilane, wherein the mass ratio of nano-lanthanum oxide to perfluorooctyltriethoxysilane is 4-6:1; S2. The reaction is refluxed at 70-80℃ for 6-10 hours, filtered, washed and dried to obtain the long-chain fluoroalkyl modified nano-lanthanum oxide.

[0024] By adopting the above technical solution, the perfluorooctyltriethoxysilane is fully hydrolyzed and condensed on the surface of nano-lanthanum oxide through a long-term reflux reaction in an ethanol / water mixed solvent. The high-fluorine-content long-chain alkyl groups shield the high-energy polar sites on the surface of lanthanum oxide.

[0025] This preparation process ensures that the modified nano-lanthanum oxide has both extremely low surface energy and high hardness of rare earth oxides, enabling it to induce the formation of a micro-nano rough structure on the outer layer of the coating that is both superhydrophobic and wear-resistant, thus solving the problems of easy shedding and short-lasting hydrophobicity of traditional nanofillers.

[0026] Optionally, the polyurethane prepolymer is an isocyanate-terminated polyurethane prepolymer with an isocyanate group content of 5-8%; the curing agent is 4,4'-methylenebis(2-chloroaniline); and the solvent for the bottom layer is a mixture of ethyl acetate and xylene at a mass ratio of 1:0.8-1.2.

[0027] By adopting the above technical solution, a polyurethane prepolymer with a terminal isocyanate group content of 5-8% is selected in combination with a specific curing agent. The appropriate amount of active isocyanate groups react with the active sites such as hydroxyl groups on the surface of the substrate. With the assistance of a mixed solvent of ethyl acetate and xylene in a specific ratio, the wettability and evaporation rate are optimized, ensuring that the bottom layer forms a network structure with a high cross-linking density during the curing process. This maximizes the chemical anchoring and mechanical interlocking effect between the coating and the wind turbine blade composite material interface, effectively preventing the coating from peeling off under high-altitude and high-speed operation.

[0028] Optionally, the low surface energy fluorosilicone resin in the outer layer has a solid content of 38-42%, and its main structural unit includes a polysiloxane backbone containing fluoroalkyl side chains; the hydrophobic nano silica is fumed silica modified with hexamethyldisilazane, with a particle size of 15-25 nm.

[0029] By employing the above technical solution, the solid content and fluorinated side chain structure of the fluorosilicone resin were limited, and small-particle-size fumed silica modified with hexamethyldisilazane was compounded. Utilizing the low surface energy of the fluoroalkyl side chains and the high specific surface area effect of nano-silica, along with rare earth oxide fillers, the rheological properties of the coating and the microstructure after film formation were optimized. This specific component design facilitates the spontaneous formation of a uniform and dense multi-level micro / nano rough structure during spraying, further reducing the roll-off angle and enhancing the self-cleaning ability of surface water droplets to remove ice crystals.

[0030] Optionally, the thicknesses of the three layers of the coating are as follows: the thickness of the bottom layer is 50-80 μm, the thickness of the middle layer is 150-200 μm, and the thickness of the outer layer is 30-50 μm.

[0031] By adopting the above technical solution, the bottom layer, with a thickness of 50-80μm, provides sufficient anchoring and thermal insulation without generating internal stress due to excessive thickness. The middle layer, with a thickness of 150-200μm, accommodates a sufficient amount of phase change microcapsules and buffer particles, ensuring excellent heat storage capacity and impact-resistant energy absorption space. The outer layer, with a thickness of 30-50μm, ensures superhydrophobicity and wear resistance while minimizing thermal resistance, allowing the latent heat energy of the middle layer to be effectively conducted to the surface. This specific thickness ratio not only optimizes material costs but also achieves a synergistic balance between mechanical properties, thermal properties, and surface protection performance.

[0032] Secondly, this application provides a method for preparing a coating for wind turbine blades, comprising the following steps: S1. Substrate treatment: Grinding, cleaning and drying the surface of the wind turbine blade substrate; S2. Preparation of the base layer: Mix all raw material components of the base layer evenly and mature for 15-30 minutes. Apply the mixture to the surface of the treated substrate using a high-pressure airless spraying method. After surface drying at room temperature for 0.5-1.5 hours, bake at 55-65℃ for 1.5-2.5 hours. S3. Preparation of intermediate layer: When the bottom layer is in a slightly tacky state, disperse the raw material components of the intermediate layer evenly at a speed of 1200-1800 rpm, spray it onto the surface of the bottom layer, and cure it at 75-85℃ for 3.5-4.5h. S4. Outer layer preparation: Mix all raw material components of the outer layer evenly, adjust the spray gun pressure to deposit the coating in the form of atomized droplets on the surface of the intermediate layer, cure at 75-85℃ for 2.5-3.5h, then let it cool naturally to room temperature and let it mature for 20-28h to obtain a coating for wind turbine blades.

[0033] By adopting the above technical solution, a "wet-on-wet" process of spraying the intermediate layer when the bottom layer is slightly tacky with a fingertip, and a staged gradient temperature curing strategy, the diffusion, entanglement, and chemical bonding of the polymer chains between layers are effectively promoted, avoiding the risk of clear delamination and peeling at the interlayer interface. Simultaneously, by controlling the spraying state and curing degree of each layer, especially the atomized droplet deposition of the outer layer, this process ensures the integrity of the three-layer structure and the orderly formation of the microstructure. This allows the prepared coating to truly achieve integrated support, buffering, hydrophobicity, and self-healing functions, guaranteeing its repeatability and high quality in practical industrial applications.

[0034] In summary, this application includes at least one of the following beneficial technical effects: 1. By constructing a three-layer composite structure consisting of a "rare earth-reinforced thermal insulation anchoring bottom layer - phase change energy storage LIPN buffer intermediate layer - rare earth-induced self-assembled superhydrophobic outer layer," the problems of low anti-icing efficiency, poor impact resistance, and insufficient adhesion of existing wind turbine blade coatings under extreme environments are systematically solved. The bottom layer utilizes the phonon scattering effect of nano-cerium oxide to construct a thermal barrier, combined with high-strength chemical anchoring of polyurethane / polydimethylsiloxane. This not only blocks ineffective heat loss to the blade substrate, ensuring the directional utilization of thermal energy in the intermediate layer, but also solves the risk of coating detachment under high-speed operation. Secondly, the intermediate layer introduces a modified fluoropolymer-siloxane LIPN latex interpenetrating network as a matrix, encapsulating DA dynamic bond modified phase change microcapsules and soft-core hard-shell IPN particles. Utilizing the unique dual-continuous phase structure of LIPN, "thermal-mechanical synergy" is achieved, that is, at low temperatures, the latent heat released through microcapsule phase change delays icing, and during freezing... When rain impacts, kinetic energy is dissipated through the high elastic deformation of the particles, and the dynamic covalent bonds on the surface of the microcapsules endow the coating with thermally reversible self-healing ability, improving the fatigue life and durability of the coating. Finally, the outer layer constructs a superhydrophobic surface with both extremely low surface energy and high hardness through the induced self-assembly of long-chain fluoroalkyl modified nano-lanthanum oxide. While achieving efficient physical water repellency, the wear-resistant properties of rare earth oxides protect the fine micro-nano structure. Thus, the coating achieves integrated anti-icing, impact resistance, wear resistance, and self-healing, ensuring the long-term stable operation of wind turbines under severe weather conditions such as freezing rain and rime. Detailed Implementation

[0035] Preparation Example 1 The modified nano-cerium oxide is prepared by the following steps: S1. Disperse 12g of nano-cerium oxide in 120mL of anhydrous ethanol and sonicate for 30min. S2. Add 1g of KH-560 silane coupling agent and adjust the pH to 4.5 with acid; S3. Stir the reaction in a water bath at 60℃ for 6 hours; after the reaction is completed, centrifuge, wash with ethanol, and vacuum dry at 80℃ for 12 hours to obtain the modified nano-cerium oxide.

[0036] Preparation Example 2 The modified nano-cerium oxide differs from Preparation Example 1 in that the silane coupling agent KH-570 is replaced with an equal amount of stearic acid.

[0037] Preparation Example 3 The modified nano-cerium oxide differs from that in Preparation Example 1 in that step S1 was not ultrasonically dispersed, but simply stirred; and the reaction temperature in step S3 was set to 25°C.

[0038] Preparation Example 4 The preparation method of the modified fluoropolymer-siloxane LIPN emulsion includes the following steps: S1. Pre-emulsification and seed polymerization: 20g of hexafluorobutyl acrylate, 30g of methyl methacrylate, 2g of vinyltriethoxysilane, 150mL of deionized water, and 1g of sodium dodecylbenzenesulfonate were mixed and pre-emulsified; the temperature was raised to 75℃, and 0.3g of potassium persulfate aqueous solution was added dropwise. The reaction was carried out for 4h to obtain fluoropropylene seed emulsion. S2, Interpenetrating network construction: Add a mixture of 40 g of octamethylcyclotetrasiloxane and 0.8 g of dodecylbenzenesulfonic acid to the seed emulsion obtained in S1, and react at 80 °C for 6 h; S3. Post-treatment: Cool to room temperature, adjust pH to 7 with alkali, and filter to obtain the modified fluororesin-siloxane LIPN emulsion.

[0039] Preparation Example 5 The modified fluoropolymer-siloxane LIPN emulsion differs from Preparation Example 4 in that the raw materials from steps S1 and S2 are mixed and added to the reaction at once, and then step S3 is carried out.

[0040] Preparation Example 6 The modified fluoropolymer-siloxane LIPN emulsion differs from Preparation Example 4 in that, in step S1, hexafluorobutyl acrylate is replaced with an equal amount of methyl methacrylate.

[0041] Preparation Example 7 The modified fluoropolymer-siloxane LIPN emulsion differs from Preparation Example 4 in that potassium persulfate is not added in step S1.

[0042] Preparation Example 8 The modified PCM microcapsules are prepared by the following steps: S1. Microencapsulation: Using n-octadecane as the core material and tetraethyl orthosilicate as the wall material precursor, silica-coated n-octadecane microcapsules were prepared by reacting under acidic conditions for 8 hours via a sol-gel method. S2, Surface functionalization: The microcapsules obtained in S1 are dispersed in an organic solvent, and 8% of furan-modified silane relative to the mass of the microcapsules is added. The reaction is carried out at 80°C for 12 hours to graft furan groups onto the surface of the microcapsules. S3. Dynamic bond construction: A bismaleimide crosslinking agent with a molar ratio of 1:1 relative to furan-modified silane was added to the S2 reaction system, and the reaction was carried out at 60°C for 3 hours. After drying, the modified PCM microcapsules were obtained.

[0043] Preparation Example 9 The modified PCM microcapsules differ from those in Preparation Example 8 in that steps S2 and S3 are not performed.

[0044] Preparation Example 10 The modified PCM microcapsules differ from those in Preparation Example 8 in that n-octadecane is replaced with an equal amount of high-melting-point paraffin (phase transition point 60°C).

[0045] Preparation Example 11 The preparation method of soft-core, hard-shell IPN colloidal particles includes the following steps: S1. Soft core synthesis: 60 parts by weight of butyl acrylate, 0.5 parts by weight of divinylbenzene, 0.8 parts by weight of emulsifier and 0.2 parts by weight of initiator are added to the reactor and reacted at 70°C for 3 hours to form a cross-linked polybutyl acrylate soft core emulsion. S2, Hard shell coating: Add a mixture of 40 parts by weight of styrene, 0.5 parts by weight of divinylbenzene and 0.2 parts by weight of initiator to the soft core emulsion obtained in S1, and continue to react at the same temperature for 4 hours. After demulsification and drying, the soft core hard shell IPN particles are obtained.

[0046] Preparation Example 12 The soft-core, hard-shell IPN particles differ from those in Preparation Example 11 in that no initiator was added in steps S1 and S2.

[0047] Preparation Example 13 The soft-core, hard-shell IPN particles differ from those in Preparation Example 11 in that styrene and divinylbenzene are not added in step S2.

[0048] Preparation Example 14 The preparation method of long-chain fluoroalkyl modified lanthanum oxide nanoparticles includes the following steps: S1. Disperse nano-lanthanum oxide in a mixed solvent of ethanol and water, and add perfluorooctyltriethoxysilane, wherein the mass ratio of nano-lanthanum oxide to perfluorooctyltriethoxysilane is 5:1. S2. The mixture was refluxed at 75°C for 8 hours, then filtered, washed, and dried to obtain the long-chain fluoroalkyl-modified nano-lanthanum oxide.

[0049] Preparation Example 15 The long-chain fluoroalkyl-modified nano-lanthanum oxide differs from Preparation Example 14 in that a short-chain silane (methyltrimethoxysilane) is used instead of a long-chain fluorosilane.

[0050] Preparation Example 16 The long-chain fluoroalkyl-modified nano-lanthanum oxide differs from that in Preparation Example 14 in that no reflux operation was performed in step S2.

[0051] Example 1 A coating for wind turbine blades, the coating having a three-layer composite structure, comprising a bottom layer, an intermediate layer and an outer layer from the wind turbine blade substrate outwards; The underlying raw material components, by weight, include: 35 parts of hydroxyl-terminated polydimethylsiloxane, 45 parts of polyurethane prepolymer, 8 parts of modified nano-cerium oxide, 6 parts of curing agent, 25 parts of solvent, and 0.8 parts of defoamer. The intermediate layer raw material components, by weight, include: 100 parts of modified fluororesin-siloxane LIPN emulsion, 20 parts of modified PCM microcapsules, 13 parts of soft-core hard-shell IPN granules, 0.8 parts of leveling agent, and 4 parts of film-forming aid. The outer layer raw material components include, by weight: 100 parts of low surface energy fluorosilicone resin, 12 parts of long-chain fluoroalkyl modified nano lanthanum oxide, 11 parts of isocyanate curing agent, 3 parts of hydrophobic nano silica, and 35 parts of solvent. The polyurethane prepolymer is an isocyanate-terminated polyurethane prepolymer with an isocyanate content of 6%; the curing agent is 4,4'-methylenebis(2-chloroaniline); the solvent of the bottom layer is a mixture of ethyl acetate and xylene in a mass ratio of 1:1; the solid content of the low surface energy fluorosilicone resin in the outer layer is 40%, and its main structural unit includes a polysiloxane backbone containing fluoroalkyl side chains; the hydrophobic nano-silica is fumed silica modified with hexamethyldisilazane and has a particle size of 15-25 nm. The modified cerium oxide nanoparticles were obtained using Preparation Example 1; the modified fluororesin-siloxane LIPN emulsion was obtained using Preparation Example 4; the modified PCM microcapsules were obtained using Preparation Example 8; the soft-core hard-shell IPN particles were obtained using Preparation Example 11; and the long-chain fluoroalkyl modified lanthanum oxide nanoparticles were obtained using Preparation Example 14.

[0052] A method for preparing a coating for wind turbine blades includes the following steps: S1. Substrate treatment: Grinding, cleaning and drying the surface of the wind turbine blade substrate; S2. Substrate preparation: Mix all raw material components of the substrate evenly and mature for 20 minutes. Apply the mixture to the surface of the treated substrate using a high-pressure airless spraying method. After surface drying at room temperature for 1 hour, bake at 60°C for 2 hours. S3. Preparation of intermediate layer: When the bottom layer is in a slightly sticky state, the raw material components of the intermediate layer are evenly dispersed at a speed of 1600 rpm, sprayed onto the surface of the bottom layer, and cured at 80℃ for 4 hours. S4. Outer layer preparation: Mix all raw material components of the outer layer evenly, adjust the spray gun pressure to make the coating be deposited on the surface of the intermediate layer in the form of atomized droplets, cure at 80℃ for 3 hours, then cool naturally to room temperature and let it mature for 24 hours to obtain a coating for wind turbine blades.

[0053] Example 2 A coating for wind turbine blades differs from Example 1 in that the bottom layer comprises, by weight, the following raw material components: 30 parts of hydroxyl-terminated polydimethylsiloxane, 40 parts of polyurethane prepolymer, 5 parts of modified nano-cerium oxide, 5 parts of curing agent, 20 parts of solvent, and 0.5 parts of defoamer.

[0054] Example 3 A coating for wind turbine blades differs from Example 1 in that the bottom layer comprises, by weight, the following raw material components: 40 parts of hydroxyl-terminated polydimethylsiloxane, 50 parts of polyurethane prepolymer, 10 parts of modified nano-cerium oxide, 8 parts of curing agent, 30 parts of solvent, and 1 part of defoamer.

[0055] Example 4 A coating for wind turbine blades differs from Example 1 in that the intermediate layer raw material components, by weight, include: 100 parts of modified fluororesin-siloxane LIPN emulsion, 15 parts of modified PCM microcapsules, 10 parts of soft-core hard-shell IPN particles, 0.5 parts of leveling agent, and 3 parts of film-forming aid.

[0056] Example 5 A coating for wind turbine blades differs from Example 1 in that the intermediate layer raw material components, by weight, include: 100 parts of modified fluororesin-siloxane LIPN emulsion, 25 parts of modified PCM microcapsules, 15 parts of soft-core hard-shell IPN particles, 1 part of leveling agent, and 5 parts of film-forming aid.

[0057] Example 6 A coating for wind turbine blades differs from Example 1 in that the outer layer raw material components, by weight, include: 100 parts of low surface energy fluorosilicone resin, 10 parts of long-chain fluoroalkyl modified nano-lanthanum oxide, 10 parts of isocyanate curing agent, 2 parts of hydrophobic nano-silica, and 30 parts of solvent.

[0058] Example 7 A coating for wind turbine blades differs from Example 1 in that the outer layer raw material components, by weight, include: 100 parts of low surface energy fluorosilicone resin, 15 parts of long-chain fluoroalkyl modified nano-lanthanum oxide, 12 parts of isocyanate curing agent, 4 parts of hydrophobic nano-silica, and 40 parts of solvent.

[0059] Comparative Example 1 A coating for wind turbine blades differs from Example 1 in that modified nano-cerium oxide is replaced with an equal amount of nano-cerium oxide.

[0060] Comparative Example 2 A coating for wind turbine blades differs from Example 1 in that the modified nano-cerium oxide is specifically obtained using Preparation Example 2.

[0061] Comparative Example 3 A coating for wind turbine blades differs from Example 1 in that the modified nano-cerium oxide is specifically obtained using Preparation Example 3.

[0062] Comparative Example 4 A coating for wind turbine blades differs from Example 1 in that the modified fluoropolymer-siloxane LIPN emulsion is specifically obtained using Preparation Example 5.

[0063] Comparative Example 5 A coating for wind turbine blades differs from Example 1 in that the modified fluoropolymer-siloxane LIPN emulsion is specifically obtained using Preparation Example 6.

[0064] Comparative Example 6 A coating for wind turbine blades differs from Example 1 in that the modified fluoropolymer-siloxane LIPN emulsion is specifically obtained using Preparation Example 7.

[0065] Comparative Example 7 A coating for wind turbine blades differs from Example 1 in that the modified PCM microcapsules are specifically obtained using Preparation Example 9.

[0066] Comparative Example 8 A coating for wind turbine blades differs from Example 1 in that the modified PCM microcapsules are specifically obtained using Preparation Example 10.

[0067] Comparative Example 9 A coating for wind turbine blades differs from Example 1 in that the soft-core, hard-shell IPN particles are specifically obtained using Preparation Example 12.

[0068] Comparative Example 10 A coating for wind turbine blades differs from Example 1 in that the soft-core, hard-shell IPN particles are specifically obtained using Preparation Example 13.

[0069] Comparative Example 11 A coating for wind turbine blades differs from Example 1 in that the long-chain fluoroalkyl-modified nano-lanthanum oxide is specifically obtained using Preparation Example 15.

[0070] Comparative Example 12 A coating for wind turbine blades differs from Example 1 in that the long-chain fluoroalkyl-modified nano-lanthanum oxide is specifically obtained using Preparation Example 16.

[0071] Detection example Ice-repellency: The ice adhesion strength was measured according to GB / T 40336-2021 "Test Method for Ice Adhesion Strength of Anti-icing Coating". A cylindrical ice column with a bottom diameter of 20 mm was prepared on the coating surface and frozen at -10℃ for 24 hours. The ice column was pushed horizontally with a thrust gauge until it fell off and the maximum thrust F was recorded. The ice adhesion strength τ=F / A, where A is the contact area. The lower the value, the better the ice-repellency. Freezing delay time: Place the sample on a cold stage with the surface temperature controlled at -10℃, add 10μL of deionized water to the coating surface, and record the time required for the water droplet to completely transform from a liquid state to a solid ice ball (become turbid). The longer the time, the better the anti-freezing performance. Abrasion resistance: The abrasion resistance test or the rotational abrasion test was used to simulate wind and sand erosion. The rotational abrasion method (Taber abrasion tester) was used with a CS-17 grinding wheel, a load of 750g, and a rotational speed of 60r / min. The mass loss (mg) after 500 revolutions of abrasion was measured. The smaller the mass loss, the better the abrasion resistance.

[0072] Long-term performance: The coating sample was placed in a UV aging test chamber and accelerated aging was carried out under UVB-313 lamp irradiation. The cycle conditions were 60℃ irradiation for 8 hours and 50℃ condensation for 4 hours. After aging for 500 hours, the ice adhesion strength was retested, and the retention rate was calculated or the ice adhesion strength value (kPa) after aging was directly compared. The lower the value and the closer it is to the initial value, the better the long-term performance. The specific test results are shown in Table 1.

[0073] Table 1

[0074] The performance test data in Table 1 of Examples 1-7 and Comparative Examples 1, 2, and 3 show that the nano-cerium oxide modified with KH-560 (Example 1) significantly outperforms the unmodified (Comparative Example 1) and stearic acid-modified (Comparative Example 2) groups in maintaining ice adhesion strength after aging. This indicates that KH-560 not only improves the dispersibility of inorganic particles in the organic resin (reducing abrasion), but also enhances the interfacial bonding force, enabling the coating to maintain a low ice adhesion force after aging. Comparative Example 3, due to a poor modification process, showed slightly better performance than Comparative Example 1 but worse performance than Example 1, demonstrating that ultrasonic dispersion and a suitable reaction temperature are crucial for the modification effect.

[0075] The performance test data in Table 1 of Examples 1-7 and Comparative Examples 4 and 5 show that the LIPN structure constructed by stepwise seed emulsion polymerization (Example 1) can significantly improve the overall performance of the coating. Comparative Example 4 used a one-time mixed polymerization, which failed to form a complete interpenetrating network structure, resulting in a shortened freezing delay time and decreased wear resistance. Comparative Example 5 removed the fluorine-containing monomer, resulting in an increase in the overall surface energy of the coating, a significant reduction in the freezing delay time to 420s, and a significant increase in ice adhesion strength, demonstrating the key role of fluorine in hydrophobic and anti-icing properties.

[0076] The performance test data in Table 1 of Examples 1-7 and Comparative Examples 7 and 8 show that the introduction of functional microcapsules mainly affects freezing delay and mechanical properties. Comparative Example 7 did not undergo surface functionalization or dynamic bond construction, resulting in poor adhesion between the microcapsules and the matrix, significantly worse wear resistance (wear loss increased to 28.5 mg), and the microcapsules were prone to detachment, leading to poor long-term effectiveness. Comparative Example 8 used high-melting-point paraffin (60°C), which could not undergo a phase transition to release latent heat under low-temperature freezing test conditions (-10°C). Therefore, its freezing delay time (650 s) was much lower than that of Example 1 (1280 s), demonstrating the importance of selecting a suitable phase transition point (n-octadecane) for utilizing the latent heat of phase transition to delay freezing.

[0077] The performance test data in Table 1 of Examples 1-7 and Comparative Example 10 show that the presence of soft-core, hard-shell IPN particles is crucial for balancing the flexibility and abrasion resistance of the coating. Comparative Example 10 removed the hard shell layer, retaining only the soft core, resulting in an excessively soft coating with extremely poor abrasion resistance (abrasion loss as high as 38.6 mg), and increased ice adhesion after aging due to surface damage. This indicates that the hard shell provides necessary rigid protection, while the soft core helps absorb impact energy (such as rain erosion).

[0078] The performance test data in Table 1 of Examples 1-7 and Comparative Examples 11 and 12 show that the long-chain fluoroalkylsilane-modified nano-lanthanum oxide plays a decisive role in constructing superhydrophobic surfaces and reducing ice adhesion. Comparative Example 11, using short-chain silane, could not provide sufficient steric hindrance and low surface energy, resulting in an initial ice adhesion strength as high as 52.1 kPa, far exceeding the 25.4 kPa of Example 1. Comparative Example 12 suffered from incomplete grafting, affecting both its ice-repellent effect and long-term effectiveness. Furthermore, increasing the amount of modified lanthanum oxide in Example 7 to 15 parts further reduced the ice adhesion strength to 23.6 kPa, but also slightly increased the wear rate, indicating that a balance needs to be struck between the amount of nanoparticles added and the ice-repellent properties.

[0079] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A coating for wind turbine blades, characterized in that, The coating is a three-layer composite structure, consisting of a bottom layer, a middle layer, and an outer layer from the wind turbine blade substrate outwards. The bottom layer is a rare earth reinforced thermal insulation anchoring layer, and its raw material components include, by weight: 30-40 parts of hydroxyl-terminated polydimethylsiloxane, 40-50 parts of polyurethane prepolymer, 5-10 parts of modified nano-cerium oxide, 5-8 parts of curing agent, 20-30 parts of solvent, and 0.5-1 parts of defoamer. The intermediate layer is a phase change energy storage LIPN buffer layer, and its raw material components include, by weight: 100 parts of modified fluororesin-siloxane LIPN emulsion, 15-25 parts of modified PCM microcapsules, 10-15 parts of soft core hard shell IPN granules, 0.5-1 parts of leveling agent, and 3-5 parts of film-forming aid. The outer layer is a rare earth-induced self-assembled superhydrophobic layer, and its raw material components include, by weight: 100 parts of low surface energy fluorosilicone resin, 10-15 parts of long-chain fluoroalkyl modified nano lanthanum oxide, 10-12 parts of isocyanate curing agent, 2-4 parts of hydrophobic nano silica, and 30-40 parts of solvent.

2. The coating for wind turbine blades according to claim 1, characterized in that, The preparation method of the modified nano-cerium oxide includes the following steps: S1. Disperse 10-15 parts by weight of nano-cerium oxide in 100-150 parts by weight of anhydrous ethanol and ultrasonically disperse for 20-40 minutes. S2. Add 1-2 parts by weight of KH-560 silane coupling agent and adjust the pH value to 4-5 with acid; S3. Stir the reaction in a water bath at 55-65℃ for 5-7 hours; after the reaction is completed, centrifuge and wash with ethanol, then vacuum dry at 70-90℃ for 10-14 hours to obtain the modified nano-cerium oxide.

3. The coating for wind turbine blades according to claim 1, characterized in that, The preparation method of the modified fluoropolymer-siloxane LIPN emulsion includes the following steps: S1. Pre-emulsification and seed polymerization: 18-22 parts by weight of hexafluorobutyl acrylate, 28-32 parts by weight of methyl methacrylate, 1-3 parts by weight of vinyltriethoxysilane, 140-160 parts by weight of deionized water, and 0.8-1.2 parts by weight of sodium dodecylbenzenesulfonate are mixed and pre-emulsified; the temperature is raised to 70-80℃, and 0.2-0.4 parts by weight of potassium persulfate aqueous solution is added dropwise, and the reaction is carried out for 3-5 hours to obtain fluoropropylene seed emulsion; S2, Interpenetrating network construction: Add a mixture of 35-45 parts by weight of octamethylcyclotetrasiloxane and 0.5-1 parts by weight of dodecylbenzenesulfonic acid to the seed emulsion obtained in S1, and react at 75-85℃ for 5-7 hours. S3. Post-treatment: Cool to room temperature, adjust pH to 7 with alkali, and filter to obtain the modified fluororesin-siloxane LIPN emulsion.

4. The coating for wind turbine blades according to claim 1, characterized in that, The preparation method of the modified PCM microcapsules includes the following steps: S1. Microencapsulation: Using n-octadecane as the core material and tetraethyl orthosilicate as the wall material precursor, silica-coated n-octadecane microcapsules were prepared by reacting under acidic conditions via a sol-gel method for 6-10 hours. S2, Surface functionalization: The microcapsules obtained in S1 are dispersed in an organic solvent, and 5-10% of furan-modified silane relative to the mass of the microcapsules is added. The reaction is carried out at 75-85℃ for 10-14 hours to graft furan groups onto the surface of the microcapsules. S3. Dynamic bond construction: Add a bismaleimide crosslinking agent with a molar ratio of 1:1 relative to furan-modified silane to the S2 reaction system, react at 55-65℃ for 2-4 h, and obtain the modified PCM microcapsules after drying.

5. A coating for wind turbine blades according to claim 1, characterized in that, The preparation method of the soft-core, hard-shell IPN colloidal particles includes the following steps: S1. Soft core synthesis: 55-65 parts by weight of butyl acrylate, 0.3-0.6 parts by weight of divinylbenzene, 0.5-1 parts by weight of emulsifier and 0.1-0.3 parts by weight of initiator are added to the reactor and reacted at 65-75℃ for 2-4 hours to form a cross-linked polybutyl acrylate soft core emulsion. S2, Hard shell coating: Add a mixture of 35-45 parts by weight of styrene, 0.3-0.6 parts by weight of divinylbenzene and 0.1-0.3 parts by weight of initiator to the soft core emulsion obtained in S1, and continue to react at the same temperature for 3-5 hours. After demulsification and drying, the soft core hard shell IPN particles are obtained.

6. The coating for wind turbine blades according to claim 1, characterized in that, The preparation method of the long-chain fluoroalkyl modified nano-lanthanum oxide includes the following steps: S1. Disperse nano-lanthanum oxide in a mixed solvent of ethanol and water, and add perfluorooctyltriethoxysilane, wherein the mass ratio of nano-lanthanum oxide to perfluorooctyltriethoxysilane is 4-6:1; S2. The reaction is refluxed at 70-80℃ for 6-10 hours, filtered, washed and dried to obtain the long-chain fluoroalkyl modified nano-lanthanum oxide.

7. A coating for wind turbine blades according to claim 1, characterized in that, The polyurethane prepolymer is an isocyanate-terminated polyurethane prepolymer with an isocyanate group content of 5-8%; the curing agent is 4,4'-methylenebis(2-chloroaniline); and the solvent for the bottom layer is a mixture of ethyl acetate and xylene in a mass ratio of 1:0.8-1.

2.

8. A coating for wind turbine blades according to claim 1, characterized in that, The outer layer contains 38-42% solids of low surface energy fluorosilicone resin, and its main structural unit includes a polysiloxane backbone containing fluoroalkyl side chains; the hydrophobic nano silica is fumed silica modified with hexamethyldisilazane, with a particle size of 15-25 nm.

9. A coating for wind turbine blades according to claim 1, characterized in that, The coating has three layers with the following thicknesses: the bottom layer has a thickness of 50-80 μm, the middle layer has a thickness of 150-200 μm, and the outer layer has a thickness of 30-50 μm.

10. A method for preparing a coating for wind turbine blades according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Substrate treatment: Grinding, cleaning and drying the surface of the wind turbine blade substrate; S2. Preparation of the base layer: Mix all raw material components of the base layer evenly and mature for 15-30 minutes. Apply the mixture to the surface of the treated substrate using a high-pressure airless spraying method. After surface drying at room temperature for 0.5-1.5 hours, bake at 55-65℃ for 1.5-2.5 hours. S3. Preparation of intermediate layer: When the bottom layer is in a slightly tacky state, disperse the raw material components of the intermediate layer evenly at a speed of 1200-1800 rpm, spray it onto the surface of the bottom layer, and cure it at 75-85℃ for 3.5-4.5h. S4. Outer layer preparation: Mix all raw material components of the outer layer evenly, adjust the spray gun pressure to deposit the coating in the form of atomized droplets on the surface of the intermediate layer, cure at 75-85℃ for 2.5-3.5h, then let it cool naturally to room temperature and let it mature for 20-28h to obtain a coating for wind turbine blades.

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