A quick-drying elastic paint for offshore wind power blades and a preparation method and application thereof

Abstract

The application relates to the field of wind power blade coatings, and particularly discloses a quick-drying elastic coating for offshore wind power blades, and a preparation method and application thereof. The coating comprises the following raw materials: aspartic ester resin, dispersing agent, anti-settling agent, defoaming agent, anti-sagging agent, barium sulfate, titanium white, water absorbent, leveling agent and solvent; isocyanate trimer, isocyanate elastic prepolymer and solvent; wherein the isocyanate elastic prepolymer is prepared by pre-polymerization of polyol and isocyanate monomer; and the isocyanate monomer is hexamethylene diisocyanate or pentamethylene diisocyanate. The quick-drying elastic coating for offshore wind power blades has better tensile property and resilience, has strong rain erosion resistance, and can form a coating layer to fully protect offshore wind power blades, especially large-size offshore wind power blades, and effectively reduces the risk of accidents of offshore wind power blades.

Description

Technical Field

[0001] This application relates to the field of coatings for wind turbine blades, and more specifically, to a quick-drying elastic coating for offshore wind turbine blades, its preparation method, and its application. Background Technology

[0002] Offshore wind turbine blades are one of the key components of wind turbine generators. Their function is to convert wind energy into mechanical energy, and then into electrical energy through a generator. Due to the harsh operating environment in my country's coastal areas, offshore wind turbine blades, compared to onshore wind turbine blades, not only have to withstand enormous loads during long-term continuous operation, but also suffer from corrosion from rainwater, salt spray, and biological debris, as well as damage from lightning strikes and typhoons. If an offshore wind turbine blade fails, it will not only result in expensive repair costs, but also cause serious losses in power generation. Therefore, in order to control risks, the coating materials used to coat the surface of offshore wind turbine blades have extremely high performance requirements.

[0003] Resin type is the most important factor affecting coating performance. Much research has been conducted both domestically and internationally on resins. Currently, the main resins applicable to coatings for offshore wind turbine blades include polyurethane resins, acrylic resins, fluorocarbon resins, silicone resins, and epoxy resins. In recent years, foreign companies have typically used polyurethane-based coatings for offshore wind turbine blades. For example, PPG has launched a thin-film protective coating system for offshore wind turbine blades consisting of a polyurethane primer and a polyurethane topcoat. This coating exhibits strong adhesion, flexibility, and rain erosion resistance. However, this coating is only suitable for the European marine environment. The climate in China differs from that abroad, and this coating is completely ineffective against high temperatures, high concentrations of salt spray and water vapor, icing, and typhoons in Chinese waters.

[0004] With the deepening research of domestic researchers on the powerful polymer material system of aspartic polyurea, aspartic polyurea coatings have become a key research focus for coatings used in offshore wind turbine blades in recent years. Aspartic polyurea systems are typically composed of aspartic ester resins combined with elastic curing agents. They possess characteristics such as high solids content, good environmental friendliness, high weather resistance, strong corrosion resistance, and excellent mechanical properties. The resulting coatings can withstand the harsh climate and environment of Chinese waters, reducing the risk of accidents involving offshore wind turbine blades and extending their service life. However, as offshore wind turbine blades become larger, their terminal linear velocity during rotation also increases, placing higher demands on the coating's resistance to rain erosion. Existing elastic curing agents are generally obtained by prepolymerizing MDI, HMDI, TDI, IPDI, and polyether or polyester polyols. While these elastic curing agents can give the coating excellent tensile properties, their resilience is poor, and the resulting coatings' resistance to rain erosion can no longer meet increasingly stringent requirements. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a quick-drying elastic coating for offshore wind turbine blades, its preparation method, and its application.

[0006] In a first aspect, this application provides a quick-drying elastic coating for offshore wind turbine blades, which adopts the following technical solution: A quick-drying elastic coating for offshore wind turbine blades, by weight, comprises the following raw materials: Component A: 20-40 parts aspartic acid ester resin, 0.5-1 parts dispersant, 0.2-0.6 parts anti-settling agent, 0.2-1 parts defoamer, 0.1-1 parts anti-sagging agent, 10-30 parts barium sulfate, 10-30 parts titanium dioxide, 0-10 parts water absorbent, 0.1-0.2 parts leveling agent, and 0-20 parts solvent; Component B: 0-30 parts isocyanate trimer, 70-100 parts isocyanate elastic prepolymer, and 0-30 parts solvent; wherein, the isocyanate elastic prepolymer is prepolymerized from polyol and isocyanate monomer; the isocyanate monomer is hexamethylene diisocyanate or pentamethylene diisocyanate.

[0007] By adopting the above technical solution, this application uses hexamethylene diisocyanate (HDI) or pentamethylene diisocyanate (PDI) as isocyanate monomers to prepolymerize with polyols to obtain isocyanate elastic prepolymers. Compared with other isocyanate monomers containing cyclic structures, such as MDI, HMDI, TDI, and IPDI, hexamethylene diisocyanate (HDI) and pentamethylene diisocyanate (PDI) are both linear aliphatic isocyanate monomers. The isocyanate elastic prepolymers obtained after prepolymerization with polyols not only have excellent tensile properties but also high resilience, reducing the possibility of the coating continuously elongating and eventually peeling off under repeated impact from sand and gravel, and significantly improving the coating's resistance to rain erosion. Furthermore, since hexamethylene diisocyanate (HDI) and pentamethylene diisocyanate (PDI) are both linear isocyanate monomers, the isocyanate elastic prepolymers obtained by using them with polyols have low viscosity. Only a small amount of solvent needs to be added during coating preparation, or even no solvent needs to be added, making it more environmentally friendly.

[0008] Isocyanate trimers are commonly used isocyanate trimers in the art, such as HDI trimer, IPDI trimer, PDI trimer, MDI trimer, TDI trimer, etc. In the specific embodiments of this application, HDI trimer is selected as an example for illustration.

[0009] The dispersant used is a commonly used dispersant in this field, such as anionic dispersants, cationic dispersants, nonionic dispersants, amphoteric wetting and dispersing agents, electrically neutral wetting and dispersing agents, polymeric hyperdispersants, and free radical hyperdispersants. All of the above dispersants can achieve good dispersion effects in this application. In a specific embodiment of this application, BYK-163, a polymeric hyperdispersant from BYK (Germany), is used as an example for illustration.

[0010] The anti-settling agent is hydrophobic fumed silica. Hydrophobic fumed silica not only gives the coating excellent anti-settling properties and storage stability when it is standing, but also gives the coating excellent flowability during construction. After adhering to the substrate, it has good anti-sagging properties, and the resulting coating has good film appearance and density.

[0011] The defoamer used is a commonly used defoamer in this field, such as polyether-type defoamers, silicone-type defoamers, and polyether-modified silicone-type defoamers. All of the above-mentioned defoamers can achieve good defoaming effects in this application. Among them, polyether-type defoamers have a more suitable oleophilic-hydrophilic ratio, a higher defoaming rate, and better compatibility with aspartic acid esters, etc. In the specific embodiments of this application, one of BYK-1790, BYK-054, and BYK-052 from BYK (Germany) is selected as an example for illustration.

[0012] In the specific embodiments of this application, the anti-sagging agent is BYK-410 from BYK (Germany), which can work effectively with the anti-settling agent to prevent sagging. The barium sulfate has a mesh size of 1250, the titanium dioxide is rutile titanium dioxide, and the water absorbent is 3A molecular sieve.

[0013] The leveling agent is a commonly used leveling agent in this field, such as polyacrylate leveling agents and fluorocarbon modified polyacrylate leveling agents. Both types of leveling agents can achieve good leveling effects in this application. In the specific embodiments of this application, one of BYK-354 and BYK-399 from BYK (Germany) and EFKA-3600 from Efka is selected as an example for illustration.

[0014] The solvent is a commonly used solvent in the art, such as ethyl acetate, n-butyl acetate, ethylene glycol diacetate, propylene glycol methyl ether acetate, No. 100 solvent oil, No. 150 solvent oil, toluene, xylene, and trimethylbenzene. In the specific embodiments of this application, n-butyl acetate is used as an example for illustration.

[0015] Preferably, the isocyanate monomer is pentamethylene diisocyanate.

[0016] By adopting the above technical solution, this application, verified by experimental data, shows that compared to hexamethylene diisocyanate (HDI), the quick-drying elastic coating for offshore wind turbine blades made from isocyanate elastic prepolymers obtained by prepolymerizing pentamethylene diisocyanate (PDI) with polyols exhibits stronger resilience. Furthermore, the coating can be used without heating during preparation, improving production efficiency. It is speculated that this is because pentamethylene diisocyanate (PDI) has lower molecular regularity than HDI, resulting in isocyanate elastic prepolymers that are less prone to crystallization, thus leading to better resilience.

[0017] Preferably, the polyol is one of polycaprolactone polyol, polytetrahydrofuran ether polyol, and polycarbonate polyol.

[0018] By adopting the above technical solution, this application uses polycaprolactone polyol, polytetrahydrofuran ether polyol, or polycarbonate polyol to prepolymerize isocyanate monomers to obtain isocyanate elastic prepolymers. These prepolymers enable the quick-drying elastic coatings for offshore wind turbine blades to remain free of coating defects after immersion in a 5 wt% sodium hydroxide solution for 10 days. In contrast, quick-drying elastic coatings for offshore wind turbine blades made from isocyanate elastic prepolymers prepared from polyols other than those mentioned above all exhibited blistering after immersion in a 5 wt% sodium hydroxide solution for 10 days. As is known to those skilled in the art, coating structures possessing both high resilience and high tensile strength inevitably contain many linear segments, and the crosslinking density cannot reach a very high level. This limits the alkali resistance of the coating. Compared to other polyols, isocyanate elastic prepolymers prepared from polycaprolactone polyol, polytetrahydrofuran ether polyol, or polycarbonate polyol can enable quick-drying elastic coatings for offshore wind turbine blades to possess both high rain erosion resistance and alkali resistance.

[0019] Preferably, the molecular weight of the polyol is 400-5000.

[0020] By adopting the above technical solution, this application optimizes the molecular weight of the polyol, resulting in a lower viscosity of the prepared isocyanate elastic prepolymer, thereby making the coating have a lower viscosity and easier to coat on the surface of offshore wind turbine blades.

[0021] Preferably, the isocyanate elastic prepolymer is prepared by the following method: The polyol and isocyanate monomer are reacted at 60-90℃ for 3-10h, and then the excess isocyanate monomer is removed by distillation at 130-135℃ and a vacuum of 0.8-1Pa to obtain the isocyanate elastomer prepolymer; wherein the molar ratio of polyol to isocyanate monomer is 1:(6-10).

[0022] Since hexamethylene diisocyanate (HDI) and pentamethylene diisocyanate (PDI) are highly toxic, this application optimizes the ratio of polyol and isocyanate monomer by adopting the above-mentioned technical solution, so that the isocyanate monomer is in excess, and then the excess isocyanate monomer is removed by distillation in a short-path evaporator, which greatly reduces the possibility of residual isocyanate monomer in the isocyanate elastic prepolymer.

[0023] Preferably, the aspartic acid ester resin is obtained by addition reaction of an amine and an ester; wherein the amine includes one or more of 1,6-hexanediamine, 2-methylpentanediamine, 1,3-cyclohexanedimethylamine, 1,3-m-phenylenediamine, 4,4-diaminodicyclohexylmethane, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, and isophoronediamine, and the ester includes one or more of dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and diisobutyl maleate.

[0024] By adopting the above technical solution, the aspartic acid ester resin obtained by the addition reaction of the above amine and ester has high reactivity, which enables the coating to dry in a short time, with the surface drying time controlled within 1 hour. This significantly reduces the probability of early dust accumulation in the coating and improves the coating's resistance to rain. At the same time, the actual drying time of the coating is 6-8 hours, and the overall production efficiency is high.

[0025] Preferably, component A in the raw material further includes 5-20 parts by weight of modified aspartic acid ester resin; the modified aspartic acid ester resin is obtained by transesterification reaction of aspartic acid ester resin and polyol; the polyol is one of polytetrahydrofuran polyol, polycaprolactone polyol, and polycarbonate polyol.

[0026] Through the above technical solution, this application involves transesterification of aspartic acid ester resin with polyols, resulting in modified aspartic acid ester resin with higher functionality. Mixing and using this modified resin with aspartic acid ester resin allows for full utilization of their synergistic effects, increasing the crosslinking density of the coating film and thus improving its strength and alkali resistance. Furthermore, experimental data shows that compared to other polyols, modified aspartic acid ester resins prepared from polytetrahydrofuran polyol, polycaprolactone polyol, and polycarbonate polyol can further improve the flexibility and rain erosion resistance of coatings.

[0027] Preferably, the molecular weight of the polyol is 500-2000.

[0028] Preferably, the molar ratio of the hydroxyl group of the polyol to the ester bond of the aspartic acid ester resin is (0.1-0.2):1.

[0029] Through the above technical solution, this application selects low molecular weight polyols and optimizes the ratio of hydroxyl groups to ester bonds in the transesterification reaction, so that the viscosity of the modified aspartic acid ester resin does not increase significantly with the modification treatment, and can still maintain a low viscosity. When preparing coatings, only a small amount of solvent needs to be added, or even no solvent needs to be added, which reduces VOC emissions and is more environmentally friendly.

[0030] Secondly, this application provides a method for preparing a quick-drying elastic coating for offshore wind turbine blades, which adopts the following technical solution: A method for preparing a quick-drying elastic coating for offshore wind turbine blades includes the following steps: All raw materials in component A, except for the leveling agent and solvent, are stirred and dispersed at a speed of 3000-3200 r / min for 10-15 min. Then, the leveling agent and solvent are added, and the mixture is stirred at a speed of 1000-1200 r / min for 8-10 min to obtain component A. All raw materials in component B are stirred at a speed of 1000-1200 r / min for 10-20 min to obtain component B.

[0031] Thirdly, the application of a quick-drying elastic coating for offshore wind turbine blades provided in this application adopts the following technical solution: An application of a fast-drying elastic coating for offshore wind turbine blades involves uniformly mixing components A and B of the aforementioned fast-drying elastic coating for offshore wind turbine blades and then coating it onto the surface of the offshore wind turbine blade to obtain a coating with a thickness of 200-600 μm.

[0032] By adopting the above technical solution, the coating with better rain erosion resistance and alkali resistance prepared in this application is applied to the surface of offshore wind turbine blades. The resulting coating can fully protect the offshore wind turbine blades, especially large-sized offshore wind turbine blades, and effectively reduce the risk of accidents involving offshore wind turbine blades.

[0033] In summary, this application has the following beneficial technical effects: 1. The isocyanate elastic prepolymer of this application not only has excellent tensile properties, but also high resilience properties, and has low viscosity. When preparing coatings, only a small amount of solvent needs to be added, or even no solvent needs to be added, which is more environmentally friendly. 2. The quick-drying elastic coating for offshore wind turbine blades of this application has good rain erosion resistance and alkali resistance. The coating formed can fully protect the offshore wind turbine blades, especially large-sized offshore wind turbine blades, and effectively reduce the risk of accidents involving offshore wind turbine blades. 3. The quick-drying elastic coating for offshore wind turbine blades of this application has a low viscosity, making it easy to apply to the surface of offshore wind turbine blades. It has good workability, and the resulting coating has good appearance and density, as well as high reactivity and overall high production efficiency. Detailed Implementation

[0034] All raw materials used in this application are commercially available, specifically: Polyester diol, purchased from Greenlink (Jining) Chemical Technology Co., Ltd., model number 7362, molecular weight 2000; Polyether diol, purchased from Greenlink (Jining) Chemical Technology Co., Ltd., with a molecular weight of 400 or 2000; Polycaprolactone diol, purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., has a molecular weight of 1000. Polycaprolactone diol, purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd., has a molecular weight of 2000. Polytetrahydrofuran ether diol was purchased from Hyosung Chemical (Jiaxing) Co., Ltd., with molecular weights of 400, 1000 or 5000 respectively; polycarbonate diol was purchased from Ube Industries, Japan, model UH-CARB100, with a molecular weight of 1000. Polycarbonate diol, purchased from Ube, Japan, model number UH-CARB50, molecular weight 500; Hexamethylene diisocyanate (HDI), purchased from Hubei Kewode Chemical Co., Ltd., has a molecular weight of 168; Pentamethylene diisocyanate (PDI), purchased from Mitsui Chemicals, with a molecular weight of 154; 1. Methylpentanediamine, purchased from Invista; 1,3-Cyclohexanedimethylamine, purchased from Mitsubishi, Japan; Diethyl maleate, purchased from Shandong Baifeng New Material Technology Co., Ltd.; Hydrophobic fumed silica, purchased from Degussa, model R972; 3A molecular sieve, purchased from Yimai Environmental Protection, specification 2-3mm; HDI trimer, purchased from Wanhua Chemical, model HT-600; Butyl acetate, purchased from Foshan Changxing New Materials Co., Ltd. MDI, purchased from Wanhua Chemical, model MDI-100, molecular weight 250; HMDI, purchased from Wanhua Chemical, with a molecular weight of 262; TDI, purchased from Wanhua Chemical, with a molecular weight of 174; IPDI, purchased from Wanhua Chemical, has a molecular weight of 222.

[0035] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0036] Preparation Example 1.1 The isocyanate elastic prepolymer was prepared by the following method: 2000g (1mol) of polyester diol (Mn = 2000) and 1008g (6mol) of hexamethylene diisocyanate (HDI) were reacted at 68℃ for 3.2h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130℃ and a vacuum of 1Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 3.60%.

[0037] Preparation Example 1.2 The difference from Preparation Example 1.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 2000 g (1 mol) of polyester diol (Mn = 2000) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 1 to obtain an isocyanate elastic prepolymer with a final NCO content of 3.64%.

[0038] Preparation Example 2.1 The isocyanate elastic prepolymer was prepared by the following method: 400 g (1 mol) of polyether diol (Mn = 400) and 1344 g (10 mol) of hexamethylene diisocyanate (HDI) were reacted at 70 °C for 3 h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130 °C and a vacuum of 1 Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 11.41%.

[0039] Preparation Example 2.2 The difference from Preparation Example 2.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 400 g (1 mol) of polyether diol (Mn = 400) and 1540 g (10 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 2 to obtain an isocyanate elastic prepolymer with a final NCO content of 11.86%.

[0040] Preparation Example 3.1 The isocyanate elastic prepolymer was prepared by the following method: 1000 g (1 mol) of polycaprolactone diol (Mn = 1000) and 1008 g (6 mol) of hexamethylene diisocyanate (HDI) were reacted at 72 °C for 2.8 h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 135 °C and a vacuum of 0.8 Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 6.29%.

[0041] Preparation Example 3.2 The difference from Preparation Example 3.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 1000 g (1 mol) of polycaprolactone diol (Mn = 1000) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 3 to obtain an isocyanate elastic prepolymer with a final NCO content of 6.42%.

[0042] Preparation Example 4.1 The isocyanate elastic prepolymer was prepared by the following method: 1000 g (1 mol) of polytetrahydrofuran ether diol (Mn = 1000) and 1008 g (6 mol) of hexamethylene diisocyanate (HDI) were reacted at 70 °C for 3 h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130 °C and a vacuum of 1 Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 6.29%.

[0043] Preparation Example 4.2 The difference from Preparation Example 4.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 1000 g (1 mol) of polytetrahydrofuran ether diol (Mn = 1000) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 4 to obtain an isocyanate elastic prepolymer with a final NCO content of 6.42%.

[0044] Preparation Example 5.1 The isocyanate elastic prepolymer was prepared by the following method: 400 g (1 mol) of polytetrahydrofuran ether diol (Mn = 400) and 1008 g (6 mol) of hexamethylene diisocyanate (HDI) were reacted at 70 °C for 3 h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130 °C and a vacuum of 1 Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 11.41%.

[0045] Preparation Example 5.2 The difference from Preparation Example 5.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 400 g (1 mol) of polytetrahydrofuran ether diol (Mn = 400) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 5 to obtain an isocyanate elastic prepolymer with a final NCO content of 11.86%.

[0046] Preparation Example 6.1 The isocyanate elastic prepolymer was prepared by the following method: 5000g (1mol) of polytetrahydrofuran ether diol (Mn = 5000) and 1008g (6mol) of hexamethylene diisocyanate (HDI) were reacted at 70℃ for 3h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130℃ and a vacuum of 1Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 1.57%.

[0047] Preparation Example 6.2 The difference from Preparation Example 6.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 5000 g (1 mol) of polytetrahydrofuran ether diol (Mn = 5000) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 6 to obtain an isocyanate elastic prepolymer with a final NCO content of 1.58%.

[0048] Preparation Example 7.1 The isocyanate elastic prepolymer was prepared by the following method: 1000 g (1 mol) of polycarbonate diol (Mn = 1000) and 1008 g (6 mol) of hexamethylene diisocyanate (HDI) were reacted at 70 °C for 3 h. Then, excess isocyanate monomers were removed by distillation using a short-path evaporator at 130 °C and a vacuum of 1 Pa to obtain an isocyanate elastomer prepolymer with a final NCO content of 6.29%.

[0049] Preparation Example 7.2 The difference from Preparation Example 7.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with pentamethylene diisocyanate (PDI), that is, 1000 g (1 mol) of polycarbonate diol (Mn = 1000) and 924 g (6 mol) of pentamethylene diisocyanate are prepared under the same conditions as in Preparation Example 7 to obtain an isocyanate elastic prepolymer with a final NCO content of 6.42%.

[0050] Comparative Preparation Example 1 The difference from Preparation Example 1.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with MDI, that is, 2000g (1mol) of polyester diol (Mn=2000) and 500g (2mol) of MDI are reacted at 72°C for 2.8h to obtain an isocyanate elastic prepolymer with a final NCO content of 3.36%.

[0051] Comparative Preparation Example 2 The difference from Preparation Example 1.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with HMDI, that is, 2000g (1mol) of polyester diol (Mn=2000) and 524g (2mol) of HMDI are reacted at 72°C for 2.8h to obtain an isocyanate elastic prepolymer with a final NCO content of 3.33%.

[0052] Comparative preparation example 3 The difference from Preparation Example 1.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with IPDI, that is, 2000g (1mol) of polyester diol (Mn=2000) and 444g (2mol) of IPDI are reacted at 72°C for 2.8h to obtain an isocyanate elastic prepolymer with a final NCO content of 3.44%.

[0053] Comparative preparation example 4 The difference from Preparation Example 1.1 is that hexamethylene methyl diisocyanate (HDI) is replaced with TDI, that is, 2000g (1mol) of polyester diol (Mn=2000) and 348g (2mol) of TDI are reacted at 72°C for 2.8h to obtain an isocyanate elastic prepolymer with a final NCO content of 3.58%.

[0054] Preparation Example 8 Aspartic acid ester resin is prepared by the following method: 116g of 2-methylpentanediamine and 344g of diethyl maleate were reacted at 70℃ for 24h to obtain aspartic acid ester resin with an amino equivalent of 230.

[0055] Preparation Example 9 Aspartic acid ester resin is prepared by the following method: 142g of 1,3-cyclohexanedimethylamine and 344g of diethyl maleate were reacted at 70℃ for 24h to obtain aspartic acid ester resin with an amino equivalent of 243.

[0056] Preparation Example 10 Modified aspartic acid ester resin was prepared by the following method: The aspartic acid ester resin prepared in Preparation Example 8 was reacted with polytetrahydrofuran diol (Mn = 1000, hydroxyl value 110 ± 10 mg KOH / g) at 110 °C for 8 h to obtain modified aspartic acid ester resin; wherein the molar ratio of the hydroxyl group of polytetrahydrofuran diol to the ester bond of the aspartic acid ester resin prepared in Preparation Example 8 was 0.1:1.

[0057] Preparation Example 11 Modified aspartic acid ester resin was prepared by the following method: The aspartic acid ester resin prepared in Preparation Example 9 was reacted with polycaprolactone diol (Mn = 2000, hydroxyl value 56 ± 5 mg KOH / g) at 110 °C for 12 h to obtain modified aspartic acid ester resin; wherein the molar ratio of the hydroxyl group of polycaprolactone diol to the ester bond of the aspartic acid ester resin prepared in Preparation Example 9 was 0.2:1.

[0058] Preparation Example 12 Modified aspartic acid ester resin was prepared by the following method: The aspartic acid ester resin prepared in Preparation Example 9 was reacted with polycarbonate diol (Mn = 500, hydroxyl value 224 ± 20 mg KOH / g) at 110 °C for 6 h to obtain modified aspartic acid ester resin; wherein the molar ratio of the hydroxyl group of the polycarbonate diol to the ester bond of the aspartic acid ester resin prepared in Preparation Example 9 was 0.15:1.

[0059] Preparation Example 13 The difference from Preparation Example 11 is that polycaprolactone diol is replaced with polyether diol (Mn = 2000, hydroxyl value 56 ± 1.5 mg KOH / g), otherwise they are the same.

[0060] Preparation Example 14 The difference from Preparation Example 11 is that the polycaprolactone diol is replaced with polyester diol (Mn = 2000, hydroxyl value 50.5 ± 3.5 mg KOH / g), otherwise they are the same.

[0061] Example 1.1 A method for preparing a quick-drying elastic coating for offshore wind turbine blades includes the following steps: First, 200g of the aspartic acid ester resin prepared in Preparation Example 8, 10g of the polymeric superdispersant BYK-163, 2g of hydrophobic fumed silica, 10g of defoamer BYK-1790, 1g of anti-sagging agent BYK-410, 300g of barium sulfate, 100g of titanium dioxide, and 100g of 3A molecular sieve were stirred and dispersed at 3000r / min for 15min. Then, 1g of leveling agent EFKA-3600 and 200g of n-butyl acetate were added, and the mixture was stirred at 1000r / min for 10min to obtain component A. 1kg of the isocyanate elastic prepolymer prepared in Preparation Example 1.1 was stirred at 1000r / min for 20min to obtain component B.

[0062] Example 1.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades includes the following steps: First, 200g of aspartic acid ester resin prepared in Preparation Example 8, 10g of polymeric superdispersant BYK-163, 2g of hydrophobic fumed silica, 10g of defoamer BYK-1790, 1g of anti-sagging agent BYK-410, 300g of barium sulfate, 100g of titanium dioxide, and 100g of 3A molecular sieve were stirred and dispersed at 3000r / min for 15min. Then, 1g of leveling agent EFKA-3600 and 200g of n-butyl acetate were added, and the mixture was stirred at 1000r / min for 10min to obtain component A. 1kg of isocyanate elastic prepolymer prepared in Preparation Example 1.2 was stirred at 1000r / min for 20min to obtain component B.

[0063] Example 2.1 A method for preparing a quick-drying elastic coating for offshore wind turbine blades includes the following steps: First, 400g of the aspartic acid ester resin prepared in Preparation Example 9, 5g of the polymeric superdispersant BYK-163, 6g of hydrophobic fumed silica, 2g of defoamer BYK-1790, 10g of anti-sagging agent BYK-410, 100g of barium sulfate, and 300g of titanium dioxide were stirred and dispersed at 3200r / min for 10min. Then, 2g of leveling agent EFKA-3600 was added, and the mixture was stirred at 1200r / min for 8min to obtain component A. 300g of HDI trimer, 700g of the isocyanate elastic prepolymer prepared in Preparation Example 2.1, and 300g of n-butyl acetate were stirred at 1200r / min for 10min to obtain component B.

[0064] Example 2.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades includes the following steps: First, 400g of the aspartic acid ester resin prepared in Preparation Example 9, 5g of the polymeric superdispersant BYK-163, 6g of hydrophobic fumed silica, 2g of defoamer BYK-1790, 10g of anti-sagging agent BYK-410, 100g of barium sulfate, and 300g of titanium dioxide were stirred and dispersed at 3200r / min for 10min. Then, 2g of leveling agent EFKA-3600 was added, and the mixture was stirred at 1200r / min for 8min to obtain component A. 300g of HDI trimer, 700g of the isocyanate elastic prepolymer prepared in Preparation Example 2.2, and 300g of n-butyl acetate were stirred at 1200r / min for 10min to obtain component B.

[0065] Examples 3.1-3.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that the isocyanate elastic prepolymer obtained in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer obtained in Preparation Examples 3.1-3.2, while the rest are the same.

[0066] Examples 4.1-4.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that the isocyanate elastic prepolymer obtained in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer obtained in Preparation Examples 4.1-4.2, while the rest are the same.

[0067] Examples 5.1-5.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that the isocyanate elastic prepolymer obtained in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer obtained in Preparation Examples 5.1-5.2, while the rest are the same.

[0068] Examples 6.1-6.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that the isocyanate elastic prepolymer obtained in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer obtained in Preparation Examples 6.1-6.2, while the rest are the same.

[0069] Examples 7.1-7.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that the isocyanate elastic prepolymer obtained in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer obtained in Preparation Examples 7.1-7.2, while the rest are the same.

[0070] Example 8.1 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that: when adding aspartic acid ester resin, 50g of the modified aspartic acid ester resin prepared in Preparation Example 10 is also added, while the rest are the same.

[0071] Example 8.2 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that: when adding aspartic acid ester resin, 200g of the modified aspartic acid ester resin prepared in Preparation Example 11 is also added, while the rest are the same.

[0072] Example 8.3 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that: when adding aspartic acid ester resin, 130g of the modified aspartic acid ester resin prepared in Preparation Example 12 is also added, while the rest are the same.

[0073] Example 8.4 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that: when adding aspartic acid ester resin, 200g of the modified aspartic acid ester resin prepared in Preparation Example 13 is also added, while the rest are the same.

[0074] Example 8.5 A method for preparing a quick-drying elastic coating for offshore wind turbine blades differs from Example 1.1 in that: when adding aspartic acid ester resin, 200g of the modified aspartic acid ester resin prepared in Preparation Example 14 is also added, while the rest are the same.

[0075] Comparative Example 1 The difference from Example 1.1 is that the isocyanate elastic prepolymer prepared in Preparation Example 1.1 is replaced with the isocyanate elastic prepolymer prepared in Comparative Preparation Example 1, and all other aspects are the same.

[0076] Comparative Example 2 The difference from Example 1.1 is that the isocyanate elastic prepolymer prepared in Preparation Example 1.1 was replaced with the isocyanate elastic prepolymer prepared in Comparative Preparation Example 2, and all other aspects are the same.

[0077] Comparative Example 3 The difference from Example 1.1 is that the isocyanate elastic prepolymer prepared in Preparation Example 1.1 was replaced with the isocyanate elastic prepolymer prepared in Comparative Preparation Example 3, and all other aspects are the same.

[0078] Comparative Example 4 The difference from Example 1.1 is that the isocyanate elastic prepolymer prepared in Preparation Example 1.1 was replaced with the isocyanate elastic prepolymer prepared in Comparative Preparation Example 4, and all other aspects are the same.

[0079] Performance testing 1. Mixed viscosity: Components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly, and the mixed viscosity was measured with a viscometer at a temperature of 23±2℃ and a humidity of 55±5%, and recorded in Table 1. 2. Surface drying time: Referring to the cotton ball blowing method in GB 1728-79, components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly and then coated on the surface of tinplate to obtain a coating with a thickness of (200±25) μm. The size of the tinplate was 120mm×50mm×(0.2-0.3)mm. The surface drying time was then measured, and the results are shown in Table 1. 3. Tensile properties: Referring to GB / T 16777-2008, components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly and then coated onto a glass plate. After curing under standard conditions for 168 hours, a coating with a thickness of (2±0.2) mm was formed. The coating was then cut with a slicer to obtain dumbbell type I specimens conforming to GB / T 528. The specimens were then stretched to fracture using a tensile testing machine at a tensile speed of 500 mm / min. The tensile strength and tensile elongation were calculated, and the results are shown in Table 1. 4. Rebound performance: Components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly and then coated onto a glass plate. After curing under standard conditions for 168 hours, a coating with a thickness of (2±0.2) mm was formed. The coating was then cut into dumbbell shapes using a slicer, with the middle layer of the coating being 25 mm long and 6 mm wide. The length of the middle layer was then stretched to 75 mm and held for 3 minutes. The coating was then released and allowed to recover on its own. After 1 minute, the length of the coating was measured and recorded as L. The rebound rate was calculated according to the formula [25-(L-25)] / 25×100%. The results are shown in Table 1. 5. Alkali resistance: Referring to Method A (immersion method) in GB / T 9274-1998, components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly and then coated on the surface of a steel plate to obtain a coating with a thickness of (200±25) μm. The steel plate dimensions were 120mm×50mm×(0.45-0.55)mm. The coated steel plate was immersed in a 5wt% sodium hydroxide solution for 10 days, and the presence of coating defects such as blistering, rusting, cracking, and peeling was recorded. The results are shown in Table 1. 6. Rain erosion resistance: Referring to the horizontal method in ASTM G73-10, components A and B of Examples 1.1-8.5 and Comparative Examples 1-4 were mixed evenly and then the rain erosion resistance time was measured in a rain erosion test system. The results are shown in Table 1.

[0080] Table 1 Performance Test Results As shown in Table 1, the mixed viscosity of the quick-drying elastic coatings for offshore wind turbine blades prepared in Examples 1.1-7.1 of this application is 650-1400 CP·s, the surface drying time is 18-40 min, the tensile strength is 15-32 MPa, the tensile elongation is 208-250%, the resilience is 85-100%, and the rain erosion resistance is 4.0-8.0 h. In contrast, the resilience of Comparative Examples 1-4 is only 30-60%, and the rain erosion resistance is only 1.0-4.0 h. The test results show that the isocyanate elastic prepolymers prepared by using HDI or PDI instead of isocyanate monomers such as MDI, HMDI, TDI, and IPDI in this application can make the quick-drying elastic coatings for offshore wind turbine blades not only have excellent tensile properties, but also good resilience properties and strong rain erosion resistance. In addition, the quick-drying elastic coating for offshore wind turbine blades prepared in this application has a low viscosity and a short surface drying time, which reduces the probability of early dust accumulation in the coating and improves the coating's resistance to rainwater. At the same time, the actual drying time of the coating is 6-8 hours as determined by the cotton ball method in GB 1728-79, and the overall production efficiency is high.

[0081] Among them, by comparing the data of each set of examples, it was found that the rebound rate of Example 1.2 was higher than that of Example 1.1, the rebound rate of Example 2.2 was higher than that of Example 2.1, the rebound rate of Example 3.2 was higher than that of Example 3.1, the rebound rate of Example 4.2 was higher than that of Example 4.1, the rebound rate of Example 5.2 was higher than that of Example 5.1, the rebound rate of Example 6.2 was higher than that of Example 6.1, and the rebound rate of Example 7.2 was higher than that of Example 7.1. The test results show that, compared with HDI, the isocyanate elastic prepolymer prepared by PDI can further improve the rebound performance of the quick-drying elastic coating for offshore wind turbine blades.

[0082] By comparing the data from Examples 3.1, 4.1, 5.1, 6.1, and 7.1 with those from Example 1.1, it can be found that the isocyanate elastic prepolymers prepared using polycaprolactone diol, polytetrahydrofuran ether diol, or polycarbonate diol can prevent coating defects in offshore wind turbine blades after immersion in a 5 wt% sodium hydroxide solution for 10 days. The test results show that using polycaprolactone diol, polytetrahydrofuran ether polyol, or polycarbonate polyol can give the fast-drying elastic coating for offshore wind turbine blades both high resistance to rain erosion and alkali resistance.

[0083] The difference between Examples 8.1-8.5 and Example 1 lies in the further addition of modified aspartic acid ester resin and aspartic acid ester resin in a mixture. As shown in Table 1, the tensile strength, alkali resistance, and rain erosion resistance of Examples 8.1-8.5 are all higher than those of Example 1.1. The test results indicate that using a mixture of modified aspartic acid ester resin and aspartic acid ester resin can further enhance the strength, alkali resistance, and rain erosion resistance of the coating. Specifically, comparing the data of Examples 8.1-8.3 with those of Examples 8.4-8.5 shows that the tensile elongation, resilience, and rain erosion resistance of Examples 8.1-8.3 are slightly higher than those of Examples 8.4-8.5. The test results indicate that using one of polytetrahydrofuran polyol, polycaprolactone polyol, or polycarbonate polyol as the polyol can further enhance the flexibility and rain erosion resistance of the coating.

[0084] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fast-drying, elastic coating for offshore wind turbine blades, characterized in that, The product comprises, by weight, the following raw materials: Component A: 20-40 parts aspartic acid ester resin, 0.5-1 part dispersant, 0.2-0.6 parts anti-settling agent, 0.2-1 part defoamer, 0.1-1 part anti-sagging agent, 10-30 parts barium sulfate, 10-30 parts titanium dioxide, 0-10 parts water absorbent, 0.1-0.2 parts leveling agent, and 0-20 parts solvent; Component B: 0-30 parts isocyanate trimer, 70-100 parts isocyanate elastic prepolymer, and 0-30 parts solvent; wherein the isocyanate elastic prepolymer is prepolymerized from polyol and isocyanate monomer; the isocyanate monomer is hexamethylene diisocyanate or pentamethylene diisocyanate; The isocyanate elastic prepolymer was prepared by the following method: The polyol and isocyanate monomer are reacted at 60-90℃ for 3-10h, and then the excess isocyanate monomer is removed by distillation at 130-135℃ and a vacuum of 0.8-1Pa to obtain the isocyanate elastomer prepolymer; wherein the molar ratio of polyol to isocyanate monomer is 1:(6-10); and the molecular weight of the polyol is 400-5000. The polyol is one of polycaprolactone polyol, polytetrahydrofuran ether polyol and polycarbonate polyol; Component A in the raw material also includes 5-20 parts by weight of modified aspartic acid ester resin; the modified aspartic acid ester resin is obtained by transesterification reaction of aspartic acid ester resin and polyol; the molecular weight of the polyol is 500-2000; the polyol is one of polytetrahydrofuran polyol, polycaprolactone polyol, and polycarbonate polyol.

2. A fast drying elastomeric coating for offshore wind turbine blades according to claim 1, characterized in that, The aspartic acid ester resin is obtained by addition reaction of an amine and an ester; wherein the amine includes one or more of 1,6-hexanediamine, 2-methylpentanediamine, 1,3-cyclohexanedimethylamine, 1,3-m-phenylenediamine, 4,4-diaminodicyclohexylmethane, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, and isophoronediamine, and the ester includes one or more of dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and diisobutyl maleate.

3. The quick-drying elastic coating for offshore wind turbine blades according to claim 1, characterized in that, In the transesterification reaction between the aspartic ester resin and the polyol, the molar ratio of the hydroxyl group of the polyol to the ester bond of the aspartic ester resin is (0.1-0.2):

1.

4. A method for preparing a quick-drying elastic coating for offshore wind turbine blades according to any one of claims 1-3, characterized in that, Includes the following steps: All raw materials in component A, except for the leveling agent and solvent, are stirred and dispersed at a speed of 3000-3200 r / min for 10-15 min. Then, the leveling agent and solvent are added, and the mixture is stirred at a speed of 1000-1200 r / min for 8-10 min to obtain component A. All raw materials in component B are stirred at a speed of 1000-1200 r / min for 10-20 min to obtain component B.

5. An application of a quick-drying elastic coating for offshore wind turbine blades, characterized in that, After uniformly mixing components A and B of the quick-drying elastic coating for offshore wind turbine blades according to any one of claims 1-3, the mixture is applied to the surface of the offshore wind turbine blade to obtain a coating with a thickness of 200-600 μm.

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