A method for preparing high-temperature resistant epoxy gel coat for wind turbine blade mold

Abstract

The present invention discloses a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, and belongs to the technical field of epoxy gel coat preparation. The method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold comprises the following steps: Step 1: vacuum dehydrating the epoxy resin to obtain a pretreated resin; Step 2: heating the pretreated resin, then adding a modified toughening agent, fumed silica, and a silane coupling agent in sequence, mixing and stirring to obtain a mixture; Step 3: cooling the mixture, then adding a curing agent, stirring at a low speed, vacuum degassing, coating, curing, spraying a modified wear-resistant agent solution, and drying to obtain a high-temperature resistant epoxy gel coat for a wind turbine blade mold. The epoxy gel coat prepared by this method has excellent toughness, high-temperature resistance, chemical corrosion resistance, and wear resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of epoxy gel coat preparation, and in particular relates to a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mould. Background Art

[0002] As core components of wind turbines, the quality and performance of wind turbine blades are crucial to the overall efficiency of wind turbine systems. Wind turbine blade molds are crucial tools in blade manufacturing, and their precision, durability, and high-temperature resistance directly impact blade molding quality and production efficiency. Traditional mold materials and technologies are no longer adequate to meet the stringent requirements of modern large-scale wind turbine blades. Therefore, developing epoxy gel coats with excellent high-temperature resistance has become a key area for improving the quality of wind turbine blade molds.

[0003] Epoxy gelcoat is a mixture of epoxy resin, curing agent, and other auxiliary materials. Epoxy resin is the primary component of the gelcoat, accounting for 70% to 80%. Its structure gives the gelcoat excellent mechanical strength, glossiness, weather resistance, and chemical resistance. The curing agent chemically reacts with the epoxy resin to form a cross-linked structure, solidifying the gelcoat and imparting the desired physical and chemical properties.

[0004] Patent CN112194961A discloses a method for making a spray gel coat and a mold, comprising an epoxy resin mixture and a curing agent, wherein the weight ratio of the epoxy resin mixture to the curing agent is 100:35. The epoxy resin mixture includes: 30-50% bisphenol A epoxy resin, 10-20% bisphenol F epoxy resin, 3-10% styrene diluent, 1-3% fumed silica, 20-40% 1200 mesh high white aluminum hydroxide, 1-5% blue color paste, 1-2% coupling agent KH-550, 0.5-1% defoaming agent BYK530, and 0.5-1% anti-sagging agent BYK-410; the curing agent includes 30-50% triethylenetetramine, 20-40% diethyltoluenediamine, 1-5% salicylic acid, and 15-35% benzyl alcohol. The gel coat prepared by this method has good mechanical properties, but the toughness, high temperature resistance, wear resistance and corrosion resistance of the gel coat prepared by this method still have room for improvement. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, which is used to solve the technical problems of poor toughness, high-temperature resistance, wear resistance and corrosion resistance of epoxy gel coat in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, comprising the following steps:

[0008] Step 1: vacuum dehydrating the epoxy resin to obtain a pretreated resin;

[0009] Step 2: heating the pretreated resin, and then sequentially adding a modified toughening agent, fumed silica, and a silane coupling agent, mixing and stirring to obtain a mixture;

[0010] Step 3: Cool the mixture, then add the curing agent, stir at a low speed, vacuum degassing, coating, curing, spraying the modified wear-resistant agent solution, and drying to obtain a high-temperature resistant epoxy gel coat for wind turbine blade molds.

[0011] Preferably, in step 1, the temperature during the vacuum dehydration treatment is 80-85° C., the dehydration time is 2-4 h, and the vacuum degree is ≤0.1 MPa.

[0012] Preferably, in the step 2, the temperature is heated to 55-65°C, the amount ratio of the pretreated resin, modified toughening agent, fumed silica and silane coupling agent is (40-60) g: (1-3) g: (0.5-0.9) g: (1.2-1.8) g, the mixing and stirring speed is 50-100 rpm, the vacuum degree is -0.05 to -0.11 MPa, and the stirring time is 30-45 min.

[0013] Preferably, in the step three, the amount ratio of the mixture and the curing agent is (45-63) g: (12-21) g, the temperature is lowered to 35-45 ° C, the low-speed stirring speed is 30-50 rpm, the stirring time is 30-45 min, the vacuum degassing treatment temperature is 38-42 ° C, the vacuum degree is -0.03 to -0.12 MPa, the treatment time is 15-20 min, and the modified wear-resistant agent solution is composed of a modified wear-resistant agent and ethyl acetate in a ratio of (8-14) g: (20-35) mL.

[0014] Preferably, the preparation method of the modified toughening agent comprises the following steps:

[0015] Q1: Tetrabromotoluene, maleic anhydride, and sodium iodide were added to a container, purged with argon, and N,N-dimethylformamide was added. The mixture was heated to react, cooled, and added to distilled water. The mixture was filtered, washed, and a precipitate was obtained. The precipitate was dried and recrystallized to obtain a crude product. The crude product, 4-tert-butylaniline, isoquinoline, and m-cresol were added to a container in sequence, purged with nitrogen, and heated to react. After the reaction, the mixture was added to methanol and stirred until a solid precipitated. The mixture was filtered, washed, dried, recrystallized, and dried in vacuo to obtain a light yellow-brown solid.

[0016] Q2: Add a light yellow-brown solid, hydrazine hydrate, and N,N-dimethylformamide to a container, heat and stir to react, and after the reaction is completed, cool, filter, wash, and dry. Then, add a sodium hydroxide aqueous solution, heat under reflux, adjust the pH, filter, wash, and vacuum dry to obtain a white solid;

[0017] Q3: Add the white solid and acetic anhydride to a container, heat to reflux for reaction, cool, filter, and wash after the reaction is completed to obtain an intermediate; add the intermediate and diisopropanolamine to a container, stir, then add p-toluenesulfonic acid, heat for reaction, continue to heat the reaction, evacuate, and let stand to cool to obtain a modified toughening agent.

[0018] In the above process, the synthetic reaction formula of the modified toughening agent is as follows:

[0019]

[0020] The results of mass spectrometry analysis of the light yellow-brown solid were: m / z: 588.30 (100.0%), 589.30 (42.0%), 590.31 (8.5%), 591.31 (1.5%), 590.30 (1.1%); the results of mass spectrometry analysis of the white solid were: m / z: 362.10 (100.0%), 363.10 (19.8%), 364.11 (1.9%), 364.10 (1.6%); the results of mass spectrometry analysis of the intermediate were: m / z: 326.08 (100.0%), 327.08 (19.7%), 328.09 (1.9%), 328.08 (1.2%).

[0021] Preferably, in Q1, the amount ratio of tetrabromotoluene, maleic anhydride, sodium iodide and N,N-dimethylformamide is (8-11) g: (3.68-4.54) g: (22-43) g: (260-310) mL, the heating reaction temperature is 80-90°C, and the reaction time is 70-75 h; the amount ratio of crude product, 4-tert-butylaniline, isoquinoline and m-cresol is (4-4.18) g: (3.85-4.13) g: (0.8-1.2) mL: (18-23) mL, the heating reaction temperature is 180-200°C, and the reaction time is 4-6 h.

[0022] Preferably, in Q2, the amount ratio of the light yellow-brown solid, hydrazine hydrate and N,N-dimethylformamide is (2-2.8) g: (30-45) mL: (58-66) mL, the heating and stirring reaction temperature is 90-110 ° C, the reaction time is 20-28 h, the mass fraction of the sodium hydroxide aqueous solution is 20 wt%, the heating reflux temperature is 90-110 ° C, the reflux time is 20-24 h, and the pH is adjusted to 3.2-4.1 with 1 mol / L hydrochloric acid.

[0023] Preferably, in Q3, the amount ratio of the white solid and acetic anhydride is (0.78-0.83) g: (20-25) mL, the heating reflux reaction temperature is 110-130 ° C, the reaction time is 20-28 h, and the product is washed with tetrahydrofuran; the molar ratio of the intermediate and diisopropanolamine is (1-1.3): (1.02-1.38), the heating reaction temperature is 140-150 ° C, the reaction time is 2-4 h, the temperature rise reaction temperature is 170-180 ° C, the reaction time is 3-6 h, and the vacuum time is 1-3 h.

[0024] Preferably, the preparation method of the modified anti-wear agent comprises the following steps:

[0025] S1: Add indole-3-carboxaldehyde to a container filled with dichloromethane, then add potassium carbonate, stir to react, slowly add benzenesulfonyl chloride dropwise, heat under reflux to react, cool after the reaction, add distilled water, extract, wash, dry, filter, and concentrate under reduced pressure to obtain intermediate A;

[0026] S2: Add intermediate A, potassium carbonate and p-methylsulfonylmethyl isocyanide to a container containing methanol, heat to reflux, cool after reflux, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter, concentrate under reduced pressure, and purify to obtain intermediate B;

[0027] S3: Add intermediate B to a container containing N,N-dimethylformamide, then add potassium carbonate and 3-(trifluoromethyl)benzyl bromide, heat and stir to react, after the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

[0028] In the above process, the synthetic reaction formula of the modified wear-resistant agent is as follows:

[0029]

[0030] The results of mass spectrometry analysis of intermediate A were: m / z: 285.05 (100.0%), 286.05 (17.3%), 287.04 (4.5%), 287.05 (2.1%); the results of mass spectrometry analysis of intermediate B were: m / z: 184.06 (100.0%), 185.07 (12.0%); the results of mass spectrometry analysis of modified wear-resistant agent were: m / z: 342.10 (100.0%), 343.10 (21.5%), 344.10 (2.4%).

[0031] Preferably, in S1, the amount ratio of indole-3-carboxaldehyde, dichloromethane, potassium carbonate and benzenesulfonyl chloride is (1.01-1.33) g: (20-25) mL: (2.01-2.42) g: (1.98-2.12) mL, the stirring reaction time is 1-2 h, the heating reflux reaction temperature is 35-45 ° C, the reflux reaction time is 9-12 h, extraction is carried out with dichloromethane, washing with saturated sodium chloride, and drying with anhydrous sodium sulfate; in S2, the amount ratio of intermediate A, potassium carbonate, p-methylsulfonylmethyl isocyanide and methanol is (0.89-0.99) g: (0.88-0.97) g: (0.61-0.69) g: (8-12) mL, the heating reflux temperature is 70-80 ° C, and the reflux time is 6-8 h.

[0032] Preferably, in S3, the usage ratio of intermediate B, N,N-dimethylformamide, potassium carbonate and 3-(trifluoromethyl)benzyl bromide is (0.12-0.24) g: (8-12) mL: (0.12-0.45) g: (0.05-0.09) mL, the heating and stirring reaction temperature is 70-80°C, and the reaction time is 4-6 h.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. The present invention first uses tetrabromotoluene, maleic anhydride, 4-tert-butylaniline, and diisopropanolamine as main raw materials to prepare a modified toughening agent, and then uses indole-3-carboxaldehyde, benzenesulfonyl chloride, p-methylsulfonylmethyl isocyanide, and 3-(trifluoromethyl)benzyl bromide as main raw materials to prepare a modified wear-resistant agent. The two are applied to the preparation process of high-temperature resistant epoxy gel coat, which can effectively improve its toughness, high-temperature resistance, chemical corrosion resistance, and wear resistance.

[0035] 2. The present invention adds the prepared modified toughening agent to the preparation process of high-temperature resistant epoxy gel coat, which can effectively improve its toughness and high-temperature resistance. The hyperbranched structure in the modified toughening agent can inhibit crack propagation, strengthen the phase interface, and form a hydrogen bond network with the epoxy matrix that can dissipate energy by dynamic fracture and recombination under the action of external force, thereby improving toughness. The amide bond, ester bond and aromatic ring structure contained in the modified toughening agent can increase the thermal decomposition temperature. The aromatic ring and chemical cross-linking synergistically restrict the movement of chain segments, increase the glass transition temperature, and thus improve the high-temperature resistance of the epoxy gel coat.

[0036] 3. The present invention adds the prepared modified wear-resistant agent to the preparation process of high-temperature resistant epoxy gel coat, which can effectively improve its high-temperature resistance, chemical corrosion resistance and wear resistance. The presence of carbon-fluorine bonds can improve the high-temperature resistance of the gel coat. The π-π conjugated system contained in the aromatic heterocycle can disperse heat, increase the thermal decomposition temperature, and thus improve the high-temperature resistance. The low surface energy of the carbon-fluorine bond group blocks the penetration of corrosive media such as water, acid, and alkali, and improves the chemical corrosion resistance of the gel coat. In addition, the aromatic heterocycle and carbon-fluorine group can increase the hardness of the gel coat, enhance the surface's scratch resistance, and improve the wear resistance. DETAILED DESCRIPTION

[0037] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] Example 1: This example discloses a method for preparing a modified toughening agent, comprising the following steps:

[0039] Q1: 9.5 g of tetrabromotoluene, 4.11 g of maleic anhydride and 32.5 g of sodium iodide were added to a container, purged with argon, and 285 mL of N,N-dimethylformamide was added. The mixture was heated at 85°C for 72 h, cooled, added to 2.5 L of distilled water, filtered, washed with distilled water to obtain a precipitate, dried at 80°C for 30 min, and recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3 to obtain a crude product; 4.09 g of the crude product, 3.94 g of 4-tert-butylaniline, 1 mL of isoquinoline and 20.5 mL of m-cresol were added to a container in sequence, purged with nitrogen, and heated at 190°C for 6 h. After the reaction, the mixture was added to methanol and stirred to obtain a solid precipitate. The mixture was filtered, washed with methanol, dried in a vacuum at 60°C for 30 min, recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3, and dried in a vacuum at 60°C for 30 min to obtain a light yellow-brown solid;

[0040] Q2: 2.4 g of light yellow-brown solid, 37.5 mL of hydrazine hydrate and 62 mL of N,N-dimethylformamide were added to a container, heated and stirred at 100°C for 24 h. After the reaction, the mixture was cooled, filtered, washed with methanol, and dried at 60°C. Then, a 20 wt% sodium hydroxide aqueous solution was added, heated under reflux at 100°C for 24 h, and the pH was adjusted to 3.6 with 1 mol / L hydrochloric acid. The mixture was filtered, washed with distilled water, and dried in vacuo at 80°C for 60 min to obtain a white solid.

[0041] Q3: Add 0.8g of white solid and 22.5mL of acetic anhydride to a container, heat under reflux at 120℃ for 24h, cool, filter, and wash with tetrahydrofuran to obtain an intermediate; add 1.81g of the intermediate and 0.851g of diisopropanolamine to a container, stir, add 0.009g of p-toluenesulfonic acid, heat at 145℃ for 2h, continue to heat to 180℃ for 6h, evacuate for 1h, and let stand to cool to obtain a modified toughening agent.

[0042] This embodiment discloses a method for preparing a modified anti-wear agent, comprising the following steps:

[0043] S1: 1.17 g of indole-3-carboxaldehyde was added to a container containing 22.5 mL of dichloromethane, followed by the addition of 2.21 g of potassium carbonate. After stirring for 2 h, 2.05 g of benzenesulfonyl chloride was slowly added dropwise. The mixture was heated under reflux at 40°C for 12 h. After the reaction, the mixture was cooled, distilled water was added, and the mixture was extracted with dichloromethane. The mixture was washed with saturated sodium chloride, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain intermediate A.

[0044] S2: 0.94 g of intermediate A, 0.92 g of potassium carbonate, and 0.65 g of p-methylsulfonylmethyl isocyanide were added to a container containing 10 mL of methanol, and the mixture was heated under reflux at 75°C for 8 h. After the reflux period, the mixture was cooled, rotary evaporated, washed, extracted, and the organic phases were combined, washed, dried, filtered, concentrated under reduced pressure, and purified to obtain intermediate B.

[0045] S3: Add 0.18 g of intermediate B to a container containing 10 mL of N,N-dimethylformamide, then add 0.26 g of potassium carbonate and 0.07 mL of 3-(trifluoromethyl)benzyl bromide, heat and stir at 75 ° C for 6 hours, after the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

[0046] This embodiment discloses a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, comprising the following steps:

[0047] Step 1: The epoxy resin is subjected to vacuum dehydration treatment at 85°C for 4 hours with a vacuum degree of ≤0.1 MPa to obtain a pretreated resin;

[0048] Step 2: Heat 50g of pretreated resin to 60°C, then add 2g of modified toughening agent, 0.7g of fumed silica and 1.6g of silane coupling agent in sequence, and stir at a vacuum degree of -0.05MPa and 100rpm for 45min to obtain a mixture;

[0049] Step 3: Cool 54g of the mixture to 40°C, then add 16.5g of curing agent, stir at 50rpm for 35min, vacuum to -0.1MPa, vacuum degassing at 40°C for 20min, coat, cure, and spray a modified wear-resistant agent solution. The modified wear-resistant agent solution is composed of a modified wear-resistant agent and ethyl acetate in a dosage ratio of 11g:27.5mL. Dry to obtain a high-temperature resistant epoxy gel coat for wind turbine blade molds.

[0050] Example 2: This example discloses a method for preparing a modified toughening agent, comprising the following steps:

[0051] Q1: 8 g of tetrabromotoluene, 3.68 g of maleic anhydride and 22 g of sodium iodide were added to a container, purged with argon, and 260 mL of N,N-dimethylformamide was added. The mixture was heated at 85°C for 72 h, cooled, added to 2.5 L of distilled water, filtered, washed with distilled water to obtain a precipitate, dried at 80°C for 30 min, and recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3 to obtain a crude product; 4 g of the crude product, 3.85 g of 4-tert-butylaniline, 0.8 mL of isoquinoline and 18 mL of m-cresol were added to a container in sequence, purged with nitrogen, and heated at 190°C for 6 h. After the reaction, the mixture was added to methanol and stirred to precipitate a solid. The mixture was filtered, washed with methanol, dried under vacuum at 60°C for 30 min, recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3, and dried under vacuum at 60°C for 30 min to obtain a light yellow-brown solid;

[0052] Q2: 2 g of light yellow-brown solid, 30 mL of hydrazine hydrate and 58 mL of N,N-dimethylformamide were added to a container, heated and stirred at 100°C for 24 h. After the reaction, the mixture was cooled, filtered, washed with methanol, and dried at 60°C. Then, a 20 wt% sodium hydroxide aqueous solution was added, heated under reflux at 100°C for 24 h, and the pH was adjusted to 3.6 with 1 mol / L hydrochloric acid. The mixture was filtered, washed with distilled water, and vacuum dried at 80°C for 60 min to obtain a white solid.

[0053] Q3: Add 0.78g of white solid and 20mL of acetic anhydride to a container, heat under reflux at 120℃ for 24h, cool, filter, and wash with tetrahydrofuran to obtain an intermediate; add 1.57g of the intermediate and 0.678g of diisopropanolamine to a container, stir, add 0.007g of p-toluenesulfonic acid, heat at 145℃ for 2h, continue to heat to 180℃ for 6h, evacuate for 1h, and let stand to cool to obtain a modified toughening agent.

[0054] This embodiment discloses a method for preparing a modified anti-wear agent, comprising the following steps:

[0055] S1: Add 1.01 g of indole-3-carboxaldehyde to a container containing 20 mL of dichloromethane, then add 2.01 g of potassium carbonate. After stirring for 2 h, slowly add 1.98 g of benzenesulfonyl chloride dropwise. Heat under reflux at 40°C for 12 h. After the reaction, cool, add distilled water, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, filter, and concentrate under reduced pressure to obtain intermediate A.

[0056] S2: 0.89 g of intermediate A, 0.88 g of potassium carbonate, and 0.61 g of p-methylsulfonylmethyl isocyanide were added to a container containing 8 mL of methanol, and the mixture was heated under reflux at 75°C for 8 h. After the reflux period, the mixture was cooled, rotary evaporated, washed, extracted, and the organic phases were combined, washed, dried, filtered, concentrated under reduced pressure, and purified to obtain intermediate B.

[0057] S3: Add 0.12 g of intermediate B to a container containing 8 mL of N,N-dimethylformamide, then add 0.12 g of potassium carbonate and 0.05 mL of 3-(trifluoromethyl)benzyl bromide, heat and stir at 75 ° C for 6 h. After the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

[0058] This embodiment discloses a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, comprising the following steps:

[0059] Step 1: The epoxy resin is subjected to vacuum dehydration treatment at 85°C for 4 hours with a vacuum degree of ≤0.1 MPa to obtain a pretreated resin;

[0060] Step 2: Heat 40g of pretreated resin at 60°C, then add 1g of modified toughening agent, 0.5g of fumed silica and 1.2g of silane coupling agent in sequence, and stir at a vacuum degree of -0.05MPa at 100rpm for 45min to obtain a mixture;

[0061] Step 3: Cool 45g of the mixture to 40°C, then add 12g of curing agent, stir at 50rpm for 35min, vacuum to -0.1MPa, vacuum degassing at 40°C for 20min, coat, cure, and spray a modified wear-resistant agent solution. The modified wear-resistant agent solution is composed of a modified wear-resistant agent and ethyl acetate in a dosage ratio of 8g:20mL, and dry to obtain a high-temperature resistant epoxy gel coat for wind turbine blade molds.

[0062] Example 3: This example discloses a method for preparing a modified toughening agent, comprising the following steps:

[0063] Q1: 11 g of tetrabromotoluene, 4.54 g of maleic anhydride and 43 g of sodium iodide were added to a container, purged with argon, 310 mL of N,N-dimethylformamide was added, and the mixture was heated at 85°C for 72 h. The mixture was cooled and added to 2.5 L of distilled water. The mixture was filtered and washed with distilled water to obtain a precipitate. The mixture was dried at 80°C for 30 min and recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3 to obtain a crude product. 4.18 g of the crude product, 4.13 g of 4-tert-butylaniline, 1.2 mL of isoquinoline and 23 mL of m-cresol were added to the container in sequence, purged with nitrogen, and heated at 190°C for 6 h. After the reaction was completed, the mixture was added to methanol and stirred to obtain a solid precipitate. The mixture was filtered and washed with methanol. The mixture was vacuum dried at 60°C for 30 min. The mixture was recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3 and vacuum dried at 60°C for 30 min to obtain a light yellow-brown solid.

[0064] Q2: 2.8 g of light yellow-brown solid, 45 mL of hydrazine hydrate and 66 mL of N,N-dimethylformamide were added to a container, heated and stirred at 100°C for 24 h. After the reaction, the mixture was cooled, filtered, washed with methanol, and dried at 60°C. Then, a 20 wt% sodium hydroxide aqueous solution was added, heated under reflux at 100°C for 24 h, and the pH was adjusted to 3.6 with 1 mol / L hydrochloric acid. The mixture was filtered, washed with distilled water, and vacuum dried at 80°C for 60 min to obtain a white solid.

[0065] Q3: Add 0.83g of white solid and 25mL of acetic anhydride to a container, heat under reflux at 120℃ for 24h, cool, filter, and wash with tetrahydrofuran to obtain an intermediate; add 2.041g of the intermediate and 0.918g of diisopropanolamine to a container, stir, add 0.01g of p-toluenesulfonic acid, heat at 145℃ for 2h, continue to heat to 180℃ for 6h, evacuate for 1h, and let stand to cool to obtain a modified toughening agent.

[0066] This embodiment discloses a method for preparing a modified anti-wear agent, comprising the following steps:

[0067] S1: 1.33 g of indole-3-carboxaldehyde was added to a container containing 25 mL of dichloromethane, followed by the addition of 2.42 g of potassium carbonate. After stirring for 2 h, 2.12 g of benzenesulfonyl chloride was slowly added dropwise. The mixture was heated under reflux at 40°C for 12 h. After the reaction, the mixture was cooled, distilled water was added, and the mixture was extracted with dichloromethane. The mixture was washed with saturated sodium chloride, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain intermediate A.

[0068] S2: 0.99 g of intermediate A, 0.97 g of potassium carbonate, and 0.69 g of p-methylsulfonylmethyl isocyanide were added to a container containing 12 mL of methanol, and the mixture was heated under reflux at 75°C for 8 h. After the reflux period, the mixture was cooled, rotary evaporated, washed, extracted, and the organic phases were combined, washed, dried, filtered, concentrated under reduced pressure, and purified to obtain intermediate B.

[0069] S3: Add 0.24 g of intermediate B to a container containing 12 mL of N,N-dimethylformamide, then add 0.45 g of potassium carbonate and 0.09 mL of 3-(trifluoromethyl)benzyl bromide, heat and stir at 75 ° C for 6 hours, after the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

[0070] This embodiment discloses a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, comprising the following steps:

[0071] Step 1: The epoxy resin is subjected to vacuum dehydration treatment at 85°C for 4 hours with a vacuum degree of ≤0.1 MPa to obtain a pretreated resin;

[0072] Step 2: Heat 60g of pretreated resin to 60°C, then add 3g of modified toughening agent, 0.9g of fumed silica and 1.8g of silane coupling agent in sequence, and stir at a vacuum degree of -0.05MPa and 100rpm for 45min to obtain a mixture;

[0073] Step 3: Cool 63g of the mixture to 40°C, then add 21g of curing agent, stir at 50rpm for 35min, vacuum to -0.1MPa, vacuum degassing at 40°C for 20min, coat, cure, and spray a modified wear-resistant agent solution. The modified wear-resistant agent solution is composed of a modified wear-resistant agent and ethyl acetate in a dosage ratio of 14g:35mL, and dry to obtain a high-temperature resistant epoxy gel coat for wind turbine blade molds.

[0074] Example 4: This example discloses a method for preparing a modified toughening agent, comprising the following steps:

[0075] Q1: 9 g of tetrabromotoluene, 3.87 g of maleic anhydride and 28 g of sodium iodide were added to a container, purged with argon, and 270 mL of N,N-dimethylformamide was added. The mixture was heated at 85°C for 72 h, cooled, added to 2.5 L of distilled water, filtered, washed with distilled water to obtain a precipitate, dried at 80°C for 30 min, and recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3 to obtain a crude product; 4.03 g of the crude product, 3.89 g of 4-tert-butylaniline, 0.9 mL of isoquinoline and 19 mL of m-cresol were added to the container in sequence, purged with nitrogen, and heated at 190°C for 6 h. After the reaction, the mixture was added to methanol and stirred to precipitate a solid. The mixture was filtered, washed with methanol, dried under vacuum at 60°C for 30 min, recrystallized with a mixed solution of tetrahydrofuran and methanol in a volume ratio of 1:3, and dried under vacuum at 60°C for 30 min to obtain a light yellow-brown solid;

[0076] Q2: 2.2 g of light yellow-brown solid, 32 mL of hydrazine hydrate and 60 mL of N,N-dimethylformamide were added to a container, heated and stirred at 100°C for 24 h. After the reaction, the mixture was cooled, filtered, washed with methanol, and dried at 60°C. Then, a 20 wt% sodium hydroxide aqueous solution was added, heated under reflux at 100°C for 24 h, and the pH was adjusted to 3.6 with 1 mol / L hydrochloric acid. The mixture was filtered, washed with distilled water, and vacuum dried at 80°C for 60 min to obtain a white solid.

[0077] Q3: Add 0.79 g of white solid and 21 mL of acetic anhydride to a container, heat under reflux at 120°C for 24 hours, cool, filter, and wash with tetrahydrofuran to obtain an intermediate; add 1.68 g of the intermediate and 0.713 g of diisopropanolamine to a container, stir, add 0.008 g of p-toluenesulfonic acid, heat at 145°C for 2 hours, continue to heat to 180°C for 6 hours, evacuate for 1 hour, and let stand to cool to obtain a modified toughening agent.

[0078] This embodiment discloses a method for preparing a modified anti-wear agent, comprising the following steps:

[0079] S1: 1.08 g of indole-3-carboxaldehyde was added to a container containing 21 mL of dichloromethane, followed by the addition of 2.09 g of potassium carbonate. After stirring for 2 h, 2.08 g of benzenesulfonyl chloride was slowly added dropwise. The mixture was heated under reflux at 40°C for 12 h. After the reaction, the mixture was cooled, distilled water was added, and the mixture was extracted with dichloromethane. The mixture was washed with saturated sodium chloride, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain intermediate A.

[0080] S2: 0.91 g of intermediate A, 0.89 g of potassium carbonate, and 0.63 g of p-methylsulfonylmethyl isocyanide were added to a container containing 9 mL of methanol, and the mixture was heated under reflux at 75°C for 8 h. After the reflux period, the mixture was cooled, rotary evaporated, washed, extracted, and the organic phases were combined, washed, dried, filtered, concentrated under reduced pressure, and purified to obtain intermediate B.

[0081] S3: Add 0.16 g of intermediate B to a container containing 9 mL of N,N-dimethylformamide, then add 0.16 g of potassium carbonate and 0.06 mL of 3-(trifluoromethyl)benzyl bromide, heat and stir at 75 ° C for 6 hours, after the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

[0082] This embodiment discloses a method for preparing a high-temperature resistant epoxy gel coat for a wind turbine blade mold, comprising the following steps:

[0083] Step 1: The epoxy resin is subjected to vacuum dehydration treatment at 85°C for 4 hours with a vacuum degree of ≤0.1 MPa to obtain a pretreated resin;

[0084] Step 2: Heat 55g of pretreated resin to 60°C, then add 1.5g of modified toughening agent, 0.6g of fumed silica and 1.3g of silane coupling agent in sequence, and stir at a vacuum degree of -0.05MPa and 100rpm for 45min to obtain a mixture;

[0085] Step 3: Cool 49g of the mixture to 40°C, then add 18g of curing agent, stir at 50rpm for 35min, vacuum to -0.1MPa, vacuum degassing at 40°C for 20min, coat, cure, and spray a modified wear-resistant agent solution. The modified wear-resistant agent solution is composed of a modified wear-resistant agent and ethyl acetate in a dosage ratio of 9g:25mL, and dry to obtain a high-temperature resistant epoxy gel coat for wind turbine blade molds.

[0086] Comparative Example 1: Compared with Example 1, in the process of preparing the high-temperature resistant epoxy gel coat in Comparative Example 1, no modified toughening agent is added, and other conditions remain unchanged.

[0087] Comparative Example 2: Compared with Example 1, in the process of preparing the high-temperature resistant epoxy gel coat in Comparative Example 2, the modified wear-resistant agent solution is not sprayed, and other conditions remain unchanged.

[0088] Experimental Example: The high temperature resistant epoxy gel coats for wind turbine blade molds prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests. The glass transition temperature of the samples was tested using a differential scanning calorimeter, the toughness of the samples was tested according to GB / T 1040.1-2018, the corrosion resistance of the samples was tested according to GB / T 10125-2021, and the wear resistance of the samples was tested according to GB / T 1768-2006. The test results are shown in Table 1:

[0089] Table 1

[0090] project Glass transition temperature / ℃ Elongation at break / % Mass reduction rate / % Wear rate / % Example 1 128 116.3 0.004 0.046 Example 2 126 114.9 0.005 0.048 Example 3 126 115.4 0.006 0.051 Example 4 127 115.8 0.008 0.049 Comparative Example 1 103 97.5 0.008 0.05 Comparative Example 2 101 114.8 0.027 0.097

[0091] The test results in Table 1 show that the epoxy gel coats prepared in Examples 1-4 of the present invention exhibit excellent toughness, high-temperature resistance, corrosion resistance, and wear resistance. A comparison between Comparative Example 1 and Examples 1-4 demonstrates that the addition of a modified toughening agent effectively improves the toughness and high-temperature resistance of the epoxy gel coat. A comparison between Comparative Example 2 and Examples 1-4 demonstrates that spraying a modified wear-resistant agent solution effectively enhances the epoxy gel coat's high-temperature resistance, chemical corrosion resistance, and wear resistance.

[0092] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0093] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold, characterized in that: The following steps are involved: Step 1: vacuum dehydrating the epoxy resin to obtain a pretreated resin; Step 2: heating the pretreated resin, and then sequentially adding a modified toughening agent, fumed silica, and a silane coupling agent, mixing and stirring to obtain a mixture; Step 3: Cooling the mixture, adding a curing agent, stirring at a low speed, vacuum degassing, coating, curing, spraying a modified wear-resistant agent solution, and drying to obtain a high-temperature resistant epoxy gel coat for a wind turbine blade mold; The preparation method of the modified toughening agent comprises the following steps: Q1: Tetrabromotoluene, maleic anhydride, and sodium iodide were added to a container, purged with argon, and N,N-dimethylformamide was added. The mixture was heated to react, cooled, and added to distilled water. The mixture was filtered, washed, and a precipitate was obtained. The precipitate was dried and recrystallized to obtain a crude product. The crude product, 4-tert-butylaniline, isoquinoline, and m-cresol were added to a container in sequence. Nitrogen was passed through the container and heated to react. After the reaction was completed, the mixture was added to methanol and stirred until a solid precipitated. The mixture was filtered, washed, dried, recrystallized, and dried in vacuo to obtain a light yellow-brown solid. Q2: Add a light yellow-brown solid, hydrazine hydrate, and N,N-dimethylformamide to a container, heat and stir to react, and after the reaction is completed, cool, filter, wash, and dry. Then, add a sodium hydroxide aqueous solution, heat under reflux, adjust the pH, filter, wash, and vacuum dry to obtain a white solid; Q3: Add the white solid and acetic anhydride to a container, heat and reflux for reaction, cool, filter, and wash after the reaction is completed to obtain an intermediate; add the intermediate and diisopropanolamine to a container, stir, and then add p-toluenesulfonic acid, heat and react, continue to heat and react, evacuate, and let stand to cool to obtain a modified toughening agent; The preparation method of the modified anti-wear agent comprises the following steps: S1: Add indole-3-carboxaldehyde to a container filled with dichloromethane, then add potassium carbonate, stir to react, slowly add benzenesulfonyl chloride dropwise, heat under reflux to react, cool after the reaction, add distilled water, extract, wash, dry, filter, and concentrate under reduced pressure to obtain intermediate A; S2: Add intermediate A, potassium carbonate and p-methylsulfonylmethyl isocyanide to a container containing methanol, heat to reflux, cool after reflux, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter, concentrate under reduced pressure, and purify to obtain intermediate B; S3: Add intermediate B to a container containing N,N-dimethylformamide, then add potassium carbonate and 3-(trifluoromethyl)benzyl bromide, heat and stir to react, after the reaction is completed, wash, extract, combine the organic phases, dry, filter, concentrate under reduced pressure, and purify to obtain a modified wear-resistant agent.

2. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In the step 1, the temperature during the vacuum dehydration treatment is 80-85° C., the dehydration time is 2-4 hours, and the vacuum degree is ≤0.1 MPa.

3. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In step 2, the temperature is heated to 55-65° C., the amount ratio of the pretreated resin, the modified toughening agent, the fumed silica, and the silane coupling agent is (40-60) g: (1-3) g: (0.5-0.9) g: (1.2-1.8) g, the mixing and stirring speed is 50-100 rpm, the vacuum degree is -0.05~-0.11 MPa, and the stirring time is 30-45 min.

4. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In the step three, the ratio of the mixture to the curing agent is (45-63) g: (12-21) g, the temperature is lowered to 35-45°C, the low-speed stirring speed is 30-50 rpm, the stirring time is 30-45 min, the vacuum degassing treatment temperature is 38-42°C, the vacuum degree is -0.03~-0.12 MPa, the treatment time is 15-20 min, and the modified wear-resistant agent solution is composed of the modified wear-resistant agent and ethyl acetate in a ratio of (8-14) g: (20-35) mL.

5. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In the Q1, the amount ratio of tetrabromotoluene, maleic anhydride, sodium iodide and N,N-dimethylformamide is (8-11) g: (3.68-4.54) g: (22-43) g: (260-310) mL, the heating reaction temperature is 80-90°C, and the reaction time is 70-75 h; the amount ratio of crude product, 4-tert-butylaniline, isoquinoline and m-cresol is (4-4.18) g: (3.85-4.13) g: (0.8-1.2) mL: (18-23) mL, the heating reaction temperature is 180-200°C, and the reaction time is 4-6 h.

6. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In Q2, the amount ratio of the light yellow-brown solid, hydrazine hydrate and N,N-dimethylformamide is (2-2.8) g: (30-45) mL: (58-66) mL, the heating and stirring reaction temperature is 90-110°C, the reaction time is 20-28 h, the mass fraction of the sodium hydroxide aqueous solution is 20 wt%, the heating reflux temperature is 90-110°C, the reflux time is 20-24 h, and the pH is adjusted to 3.2-4.1 with 1 mol / L hydrochloric acid.

7. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In the Q3, the amount ratio of the white solid and acetic anhydride is (0.78-0.83) g: (20-25) mL, the heating reflux reaction temperature is 110-130 ° C, the reaction time is 20-28 h, and the product is washed with tetrahydrofuran; the molar ratio of the intermediate and diisopropanolamine is (1-1.3): (1.02-1.38), the heating reaction temperature is 140-150 ° C, the reaction time is 2-4 h, the warming reaction temperature is 170-180 ° C, the reaction time is 3-6 h, and the vacuum time is 1-3 h.

8. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In S1, the amount ratio of indole-3-carboxaldehyde, dichloromethane, potassium carbonate and benzenesulfonyl chloride is (1.01-1.33) g: (20-25) mL: (2.01-2.42) g: (1.98-2.12) mL, the stirring reaction time is 1-2 h, the heating reflux reaction temperature is 35-45°C, the reflux reaction time is 9-12 h, extraction is performed with dichloromethane, washing with saturated sodium chloride, and drying with anhydrous sodium sulfate. In S2, the amount ratio of intermediate A, potassium carbonate, p-methylsulfonylmethyl isocyanide and methanol is (0.89-0.99) g: (0.88-0.97) g: (0.61-0.69) g: (8-12) mL, the heating reflux temperature is 70-80°C, and the reflux time is 6-8 h.

9. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 1, characterized in that: In S3, the usage ratio of intermediate B, N,N-dimethylformamide, potassium carbonate and 3-(trifluoromethyl)benzyl bromide is (0.12-0.24) g: (8-12) mL: (0.12-0.45) g: (0.05-0.09) mL. The reaction temperature is 70-80°C with heating and stirring, and the reaction time is 4-6 h.

Images