Preparation method of high-temperature-resistant epoxy gel coat for wind power blade mold

Abstract

The invention discloses a preparation method of a high-temperature-resistant epoxy gel coat for a wind power blade mold, and belongs to the technical field of preparation of epoxy gel coats. The preparation method of the high-temperature-resistant epoxy gel coat for the wind power blade mold comprises the following steps: step 1, carrying out vacuum dehydration treatment on epoxy resin to obtain pretreated resin; 2, the pretreated resin is heated, then a modified flexibilizer, fumed silica and a silane coupling agent are sequentially added, mixing and stirring are conducted, and a mixture is obtained; and 3, cooling the mixture, adding a curing agent, stirring at a low speed, carrying out vacuum defoaming treatment, coating, curing, spraying the modified wear-resistant agent solution, and drying to obtain the high-temperature-resistant epoxy gel coat for the wind power blade mold. The epoxy gel coat prepared by the 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 particularly relates to a preparation method of a high-temperature resistant epoxy gel coat for wind power blade molds. Background Art

[0002] As a core component of a wind turbine, the quality and performance of a wind power blade are crucial to the overall efficiency of the wind power system. The wind power blade mold is a key tool for manufacturing the blade, and its accuracy, durability, and high-temperature resistance directly affect the molding quality and production efficiency of the blade. Traditional mold materials and technologies have become inadequate when faced with the high requirements of modern large wind power blades. Therefore, developing an epoxy gel coat with excellent high-temperature resistance has become an important direction for improving the quality of wind power blade molds.

[0003] Epoxy gel coat is a mixture composed of epoxy resin, curing agent, and other auxiliary materials. Among them, epoxy resin is the main component of the gel coat, accounting for 70% to 80% of the proportion. The structure of epoxy resin endows the gel coat with good mechanical strength, brightness, weather resistance, and chemical resistance. The curing agent forms a cross-linked structure by chemically reacting with epoxy resin, making the gel coat cured and possessing the required physical and chemical properties.

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

[0005] The purpose of the present invention is to provide a preparation method of a high-temperature resistant epoxy gel coat for wind power blade molds, aiming 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] To achieve the above purpose, the present invention adopts the following technical solutions:

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

[0008] Step 1: Perform vacuum dehydration treatment on epoxy resin to obtain pretreated resin;

[0009] Step 2: Heat the pretreated resin, and then successively add a modified toughening agent, fumed silica, and a silane coupling agent, mix and stir to obtain a mixture;

[0010] Step 3: Cool the mixture, then add a curing agent, stir at a low speed, perform vacuum defoaming treatment, coat, cure, spray a modified wear-resistant agent solution, and dry to obtain a high-temperature resistant epoxy gel coat for a wind power blade mold.

[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 ≤ 0.1 MPa.

[0012] Preferably, in Step 2, heat to 55 - 65°C, and the dosage 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 Step 3, the dosage ratio of the mixture and the curing agent is (45 - 63) g : (12 - 21) g, cool to 35 - 45°C, the low-speed stirring speed is 30 - 50 rpm, the stirring time is 30 - 45 min, the temperature of the vacuum defoaming treatment 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 consists of a modified wear-resistant agent and ethyl acetate with a dosage ratio of (8 - 14) g : (20 - 35) mL.

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

[0015] Q1: Add tetrabromotoluene, maleic anhydride, and sodium iodide into a container, introduce argon, add N,N-dimethylformamide, heat and react, cool, add to distilled water, perform suction filtration, washing to obtain a precipitate, dry, recrystallize to obtain a crude product; successively add the crude product, 4-tert-butylaniline, isoquinoline, and m-cresol into a container, introduce nitrogen, heat and react, after the reaction ends, add to methanol, stir until a solid precipitates, perform suction filtration, washing, drying, recrystallize, and vacuum dry to obtain a light yellow-brown solid;

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

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

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

[0019]

[0020] The results of mass spectrometry analysis of the light yellow-brown solid are: 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 are: 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 are: m / z: 326.08 (100.0%), 327.08 (19.7%), 328.09 (1.9%), 328.08 (1.2%).

[0021] Preferably, in Q1, the dosage 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 dosage ratio of the 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 dosage 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 aqueous sodium hydroxide 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 dosage ratio of the white solid to 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 it is washed with tetrahydrofuran; the molar ratio of the intermediate to 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-rising reaction temperature is 170 - 180 °C, the reaction time is 3 - 6 h, and the vacuum pumping time is 1 - 3 h.

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

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

[0026] S2: Add intermediate A, potassium carbonate, and tosylmethyl isocyanide to a container containing methanol, heat under reflux, after the reflux ends, cool, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter by suction, 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 ends, wash, extract, combine the organic phases, dry, filter by suction, concentrate under reduced pressure, and purify to obtain the modified wear-resistant agent.

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

[0029]

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

[0031] Preferably, in S1, the dosage 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 is carried out with saturated sodium chloride, and drying is carried out with anhydrous sodium sulfate; in S2, the dosage ratio of intermediate A, potassium carbonate, tosylmethyl 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 dosage 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 solutions, the beneficial effects of the present invention are as follows:

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

[0035] 2. Adding the prepared modified toughening agent to the preparation process of the high-temperature resistant epoxy gel coat 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 consume energy through dynamic fracture and recombination under external force, improving toughness. The amide bonds, ester bonds and aromatic ring structures contained in the modified toughening agent can increase the thermal decomposition temperature. The aromatic ring and chemical crosslinking cooperate to restrict the movement of chain segments and increase the glass transition temperature, thereby improving the high-temperature resistance of the epoxy gel coat.

[0036] 3. The modified wear-resistant agent prepared in the present invention is added to the preparation process of the high-temperature resistant epoxy gel coat, which can effectively improve its high-temperature resistance, chemical corrosion resistance and wear resistance. The presence of the carbon-fluorine bond can improve the high-temperature resistance of the gel coat, and the π-π conjugate system contained in the heteroaromatic ring can disperse heat and increase the thermal decomposition temperature, thereby enhancing the high-temperature resistance. The low surface energy of the carbon-fluorine bond group blocks the penetration of corrosive media such as water, acids and alkalis, improving the chemical corrosion resistance of the gel coat. In addition, the heteroaromatic ring and the carbon-fluorine group can increase the hardness of the gel coat, enhance the scratch resistance of the surface, and improve the wear resistance. Detailed implementation mode

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Example 1: This example discloses a preparation method of a modified toughening agent, which includes the following steps:

[0039] Q1: Add 9.5 g of tetrabromotoluene, 4.11 g of maleic anhydride and 32.5 g of sodium iodide into a container, introduce argon, add 285 mL of N,N-dimethylformamide, and react at 85 °C for 72 h. After cooling, add it to 2.5 L of distilled water, filter by suction, wash with distilled water to obtain a precipitate, dry at 80 °C for 30 min, and recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3 to obtain a crude product; Add 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 into the container in sequence, introduce nitrogen, and react at 190 °C for 6 h. After the reaction is completed, add it to methanol, stir until a solid precipitates, filter by suction, wash with methanol, dry in vacuum at 60 °C for 30 min, recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3, and dry in vacuum at 60 °C for 30 min to obtain a light yellow-brown solid;

[0040] Q2: Add 2.4 g of the light yellow-brown solid, 37.5 mL of hydrazine hydrate and 62 mL of N,N-dimethylformamide into a container, stir and react at 100 °C for 24 h. After the reaction is completed, cool, filter, wash with methanol, dry at 60 °C, then add a sodium hydroxide aqueous solution with a mass fraction of 20 wt%, heat and reflux at 100 °C for 24 h, adjust the pH = 3.6 with 1 mol / L hydrochloric acid, filter, wash with distilled water, and dry in vacuum at 80 °C for 60 min to obtain a white solid;

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

[0042] This example discloses a preparation method of a modified wear-resistant agent, including the following steps:

[0043] S1: Add 1.17 g of indole-3-carbaldehyde into a container containing 22.5 mL of dichloromethane, then add 2.21 g of potassium carbonate, stir and react for 2 h, slowly dropwise add 2.05 g of benzenesulfonyl chloride, heat and reflux at 40 °C for 12 h. After the reaction is completed, cool, add distilled water, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, filter by suction, and concentrate under reduced pressure to obtain intermediate A;

[0044] S2: Add 0.94 g of intermediate A, 0.92 g of potassium carbonate and 0.65 g of tosylmethyl isocyanide into a container containing 10 mL of methanol, heat and reflux at 75 °C for 8 h. After the reflux is completed, cool, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter by suction, concentrate under reduced pressure, and purify to obtain intermediate B;

[0045] S3: Add 0.18 g of intermediate B into 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 h. After the reaction is completed, wash, extract, combine the organic phases, dry, filter by suction, concentrate under reduced pressure, and purify to obtain the modified wear-resistant agent.

[0046] This example discloses a preparation method of a high-temperature resistant epoxy gel coat for a wind power blade mold, including the following steps:

[0047] Step 1: Perform vacuum dehydration treatment on the epoxy resin at 85 °C for 4 h, with the vacuum degree ≤ 0.1 MPa, to obtain a pretreated resin;

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

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

[0050] Example 2: This example discloses a preparation method of a modified toughening agent, which includes the following steps:

[0051] Q1: Add 8 g of tetrabromotoluene, 3.68 g of maleic anhydride, and 22 g of sodium iodide into a container, introduce argon, add 260 mL of N,N-dimethylformamide, heat and react at 85 °C for 72 h, cool, add it to 2.5 L of distilled water, perform suction filtration, wash with distilled water to obtain a precipitate, dry at 80 °C for 30 min, and perform recrystallization with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3 to obtain a crude product; Add 4 g of the crude product, 3.85 g of 4-tert-butylaniline, 0.8 mL of isoquinoline, and 18 mL of m-cresol into the container in sequence, introduce nitrogen, heat and react at 190 °C for 6 h. After the reaction is completed, add it to methanol, stir to precipitate a solid, perform suction filtration, wash with methanol, vacuum dry at 60 °C for 30 min, perform recrystallization with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3, and vacuum dry at 60 °C for 30 min to obtain a light yellow-brown solid;

[0052] Q2: Add 2 g of the light yellow-brown solid, 30 mL of hydrazine hydrate, and 58 mL of N,N-dimethylformamide into a container, heat and stir at 100 °C for 24 h. After the reaction is completed, cool, filter, wash with methanol, dry at 60 °C, then add a sodium hydroxide aqueous solution with a mass fraction of 20 wt%, heat and reflux at 100 °C for 24 h, adjust the pH = 3.6 with 1 mol / L hydrochloric acid, filter, wash with distilled water, and vacuum dry at 80 °C for 60 min to obtain a white solid;

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

[0054] This example discloses a preparation method of a modified wear-resistant agent, which includes the following steps:

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

[0056] S2: Add 0.89 g of intermediate A, 0.88 g of potassium carbonate, and 0.61 g of tosylmethyl isocyanide into a container containing 8 mL of methanol, heat under reflux at 75 °C for 8 h. After the reflux is completed, cool, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter by suction, concentrate under reduced pressure, and purify to obtain intermediate B;

[0057] S3: Add 0.12 g of intermediate B into 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 by suction, concentrate under reduced pressure, and purify to obtain the modified wear-resistant agent.

[0058] This example discloses a preparation method of a high-temperature resistant epoxy gel coat for a wind power blade mold, including the following steps:

[0059] Step 1: Carry out vacuum dehydration treatment on the epoxy resin at 85 °C for 4 h, with the vacuum degree ≤ 0.1 MPa, to obtain the pretreated resin;

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

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

[0062] Example 3: This example discloses a preparation method of a modified toughening agent, including the following steps:

[0063] Q1: Add 11 g of tetrabromotoluene, 4.54 g of maleic anhydride, and 43 g of sodium iodide into a container, introduce argon, add 310 mL of N,N-dimethylformamide, heat and react at 85 °C for 72 h, cool, add it to 2.5 L of distilled water, perform suction filtration, wash with distilled water to obtain a precipitate, dry at 80 °C for 30 min, and recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3 to obtain a crude product; add 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 into the container in sequence, introduce nitrogen, heat and react at 190 °C for 6 h. After the reaction is completed, add it to methanol, stir to precipitate a solid, perform suction filtration, wash with methanol, vacuum dry at 60 °C for 30 min, recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3, and vacuum dry at 60 °C for 30 min to obtain a light yellowish brown solid;

[0064] Q2: Add 2.8 g of the light yellowish brown solid, 45 mL of hydrazine hydrate, and 66 mL of N,N-dimethylformamide into a container, heat and stir at 100 °C for 24 h. After the reaction is completed, cool, filter, wash with methanol, dry at 60 °C, then add a 20 wt% aqueous sodium hydroxide solution, heat and reflux at 100 °C for 24 h, adjust the pH to 3.6 with 1 mol / L hydrochloric acid, filter, wash with distilled water, and vacuum dry at 80 °C for 60 min to obtain a white solid;

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

[0066] This example discloses a preparation method of a modified wear-resistant agent, including the following steps:

[0067] S1: Add 1.33 g of indole-3-carbaldehyde into a container equipped with 25 mL of dichloromethane, then add 2.42 g of potassium carbonate, stir and react for 2 h, slowly dropwise add 2.12 g of benzenesulfonyl chloride, heat and reflux at 40 °C for 12 h. After the reaction is completed, cool, add distilled water, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, perform suction filtration, and concentrate under reduced pressure to obtain intermediate A;

[0068] S2: Add 0.99 g of intermediate A, 0.97 g of potassium carbonate, and 0.69 g of p-toluenesulfonylmethyl isocyanide into a container containing 12 mL of methanol. Heat under reflux at 75 °C for 8 h. After the reflux ends, cool, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter by suction, concentrate under reduced pressure, and purify to obtain intermediate B;

[0069] S3: Add 0.24 g of intermediate B into 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 h. After the reaction ends, wash, extract, combine the organic phases, dry, filter by suction, concentrate under reduced pressure, and purify to obtain the modified wear-resistant agent.

[0070] This example discloses a preparation method of a high-temperature resistant epoxy gel coat for a wind power blade mold, including the following steps:

[0071] Step 1: Perform vacuum dehydration treatment on the epoxy resin at 85 °C for 4 h, with the vacuum degree ≤ 0.1 MPa, to obtain the pretreated resin;

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

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

[0074] Example 4: This example discloses a preparation method of a modified toughening agent, including the following steps:

[0075] Q1: Add 9 g of tetrabromotoluene, 3.87 g of maleic anhydride, and 28 g of sodium iodide into a container, introduce argon, add 270 mL of N,N-dimethylformamide, heat and react at 85 °C for 72 h, cool, add it to 2.5 L of distilled water, filter by suction, wash with distilled water to obtain a precipitate, dry at 80 °C for 30 min, and recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3 to obtain a crude product; add 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 into a container in sequence, introduce nitrogen, heat and react at 190 °C for 6 h. After the reaction is completed, add it to methanol, stir to precipitate a solid, filter by suction, wash with methanol, dry in vacuum at 60 °C for 30 min, recrystallize with a mixed solution of tetrahydrofuran and methanol with a volume ratio of 1:3, and dry in vacuum at 60 °C for 30 min to obtain a light yellow-brown solid;

[0076] Q2: Add 2.2 g of the light yellow-brown solid, 32 mL of hydrazine hydrate, and 60 mL of N,N-dimethylformamide into a container, heat and stir at 100 °C for 24 h. After the reaction is completed, cool, filter, wash with methanol, dry at 60 °C, then add a 20 wt% aqueous sodium hydroxide solution, heat and reflux at 100 °C for 24 h, adjust the pH to 3.6 with 1 mol / L hydrochloric acid, filter, wash with distilled water, and dry in vacuum at 80 °C for 60 min to obtain a white solid;

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

[0078] This example discloses a preparation method of a modified wear-resistant agent, including the following steps:

[0079] S1: Add 1.08 g of indole-3-carbaldehyde into a container containing 21 mL of dichloromethane, then add 2.09 g of potassium carbonate, stir and react for 2 h, slowly dropwise add 2.08 g of benzenesulfonyl chloride, heat and reflux at 40 °C for 12 h. After the reaction is completed, cool, add distilled water, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, filter by suction, and concentrate under reduced pressure to obtain intermediate A;

[0080] S2: Add 0.91 g of intermediate A, 0.89 g of potassium carbonate, and 0.63 g of p-toluenesulfonylmethyl isocyanide into a container containing 9 mL of methanol. Heat under reflux at 75 °C for 8 h. After the reflux ends, cool, rotary evaporate, wash, extract, combine the organic phases, wash, dry, filter by suction, concentrate under reduced pressure, and purify to obtain intermediate B;

[0081] S3: Add 0.16 g of intermediate B into 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. Stir and react at 75 °C for 6 h. After the reaction ends, wash, extract, combine the organic phases, dry, filter by suction, concentrate under reduced pressure, and purify to obtain the modified wear-resistant agent.

[0082] This example discloses a preparation method of a high-temperature resistant epoxy gel coat for a wind turbine blade mold, including the following steps:

[0083] Step 1: Perform vacuum dehydration treatment on the epoxy resin at 85 °C for 4 h with a vacuum degree ≤ 0.1 MPa to obtain the pretreated resin;

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

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

[0086] Comparative Example 1: Compared with Example 1, in the process of preparing the high-temperature resistant epoxy gel coat in Comparative Example 1, the modified toughening agent is not 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 / °C 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] As can be seen from the test results in Table 1, the epoxy gel coats prepared in Examples 1-4 of the present invention have excellent toughness, high-temperature resistance, corrosion resistance and wear resistance. By comparing Comparative Example 1 with Examples 1-4, it can be seen that adding a modified toughening agent can effectively improve the toughness and high-temperature resistance of the epoxy gel coat; by comparing Comparative Example 2 with Examples 1-4, it can be seen that spraying a modified wear-resistant agent solution can effectively improve the high-temperature resistance, chemical corrosion resistance and wear resistance of the epoxy gel coat.

[0092] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

[0093] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific embodiments. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited 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 three: 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.

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 the 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 to -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 dosage 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 to -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 dosage 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: The preparation method of the modified toughening agent comprises the following steps: Q1: Tetrabromotoluene, maleic anhydride and sodium iodide are added to a container, argon is introduced, N,N-dimethylformamide is added, heating is performed, cooling is performed, adding to distilled water, suction filtering, washing, obtaining a precipitate, drying, recrystallizing, and obtaining a crude product; the crude product, 4-tert-butylaniline, isoquinoline and m-cresol are added to a container in sequence, nitrogen is introduced, heating is performed, after the reaction is completed, adding to methanol, stirring until a solid precipitates, suction filtering, washing, drying, recrystallizing, and vacuum drying are performed to obtain a light yellow-brown solid; Q2: Add light yellow-brown solid, hydrazine hydrate and N,N-dimethylformamide to a container, heat and stir to react, cool, filter, wash, and dry after the reaction is completed, then add sodium hydroxide aqueous solution, heat and reflux, adjust the pH, filter, wash, and vacuum dry to obtain a white solid; Q3: Add the white solid and acetic anhydride into a container, heat to reflux for reaction, and after the reaction is completed, cool, filter, and wash to obtain an intermediate; add the intermediate and diisopropanolamine into a container, stir, add p-toluenesulfonic acid, heat for reaction, continue to heat the reaction, evacuate, and let stand to cool to obtain a modified toughening agent.

6. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 5, characterized in that: In the Q1, the dosage 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 dosage 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.

7. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 5, characterized in that: In the Q2, the amount ratio of 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.

8. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 5, 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 20-28h, 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 2-4h, the heating reaction temperature is 170-180°C, the reaction time is 3-6h, and the vacuuming time is 1-3h.

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: 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 for reaction, slowly drop benzenesulfonyl chloride, heat under reflux for reaction, after the reaction is completed, cool, add distilled water, extract, wash, dry, filter, and concentrate under reduced pressure to obtain intermediate A; S2: adding intermediate A, potassium carbonate and p-methylsulfonylmethyl isocyanide to a container containing methanol, heating to reflux, cooling after reflux, rotary evaporation, washing, extraction, combining organic phases, washing, drying, suction filtering, concentrating under reduced pressure, and purifying 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, purify, and obtain a modified wear-resistant agent.

10. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 9, characterized in that: In the 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, the extraction is carried out with dichloromethane, the washing is carried out with saturated sodium chloride, and the drying is carried out with anhydrous sodium sulfate; in the 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.

11. The method for preparing a high temperature resistant epoxy gel coat for a wind turbine blade mold according to claim 9, 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 heating and stirring reaction temperature is 70-80° C., and the reaction time is 4-6 h.

Images