Wind power level CFRP reinforcing rib wind power blade structural adhesive and preparation method thereof

Abstract

The application discloses a wind power blade structural adhesive for wind power grade CFRP reinforcing bars and a preparation method thereof, and relates to the technical field of high-performance composite material bonding for wind power blade manufacturing. The adhesive comprises component A and component B. The component A comprises the following raw materials in parts by weight: bisphenol A type epoxy resin, 40-70 parts; bisphenol F type epoxy resin, 20-40 parts; core-shell powder particle dispersion, 10-20 parts; active diluent, 5-10 parts; silane coupling agent, 0-8 parts; and filler, 20-35 parts. The component B comprises the following raw materials in parts by weight: epoxy chloropropane modified MXDA, 40-50 parts; PTMEG polyether modified amine, 20-30 parts; accelerator, 0.5-2 parts; filler, 15-25 parts; and auxiliary agent, 3-5 parts. The weight ratio of the component A to the component B is as follows: component A: component B = 100: 25-40. The prepared structural adhesive has excellent flexibility and fatigue resistance, high strength and high bonding force, excellent high and low temperature resistance, low sensitivity to climate environment, and is compatible with the wind power blade manufacturing process, and is especially suitable for structural bonding of CFRP reinforcing bars.

Description

Technical Field

[0001] This invention relates to the field of high-performance composite material bonding technology for wind turbine blade manufacturing, specifically to structural adhesive for wind turbine blades using CFRP reinforcing ribs and its preparation method. Background Technology

[0002] The trend towards larger wind turbine blades is a significant development trend in the wind power industry. To improve blade stiffness and load-bearing capacity, CFRP (compound fiber reinforced polymer) materials are commonly used as reinforcement materials for key components such as the blade main spars and stiffeners. These CFRP components require high-strength, high-toughness, and durable structural adhesives for bonding with the blade shell.

[0003] Currently, most structural adhesives for wind turbine blades use epoxy resin systems, but these generally suffer from the following problems: 1. They are brittle after curing, making them prone to microcracks when subjected to fatigue loads during blade operation; 2. Their toughness decreases significantly at low temperatures, affecting the reliability of the blades in cold regions; 3. They have insufficient bonding strength at the interface between CFRP and glass fiber reinforced composite (GFRP); 4. The curing speed is not well matched with the blade manufacturing process, affecting production efficiency.

[0004] Therefore, it is of great significance to develop a structural adhesive for wind turbine blades that combines high strength, high toughness, excellent interfacial bonding performance, and good process adaptability. Summary of the Invention

[0005] The present invention provides a wind turbine blade structural adhesive for wind turbine-grade CFRP reinforcing ribs and its preparation method, aiming to solve the problems existing in the above-mentioned background art.

[0006] To achieve the above-mentioned technical objectives, the present invention mainly adopts the following technical solutions: In a first aspect, the present invention discloses a high-performance structural adhesive suitable for bonding CFRP reinforcing ribs of wind turbine blades, characterized in that it comprises component A and component B, wherein component A comprises the following raw materials in parts by weight: bisphenol A epoxy resin: 40-70 parts; bisphenol F epoxy resin: 20-40 parts; core-shell powder particle dispersion: 10-20 parts; reactive diluent: 5-10 parts; silane coupling agent: 0-8 parts; filler: 20-35 parts; Bisphenol A and bisphenol F epoxy resins are used as the main resins: bisphenol A epoxy resin provides high strength, high modulus and heat resistance; bisphenol F epoxy resin reduces the viscosity of the system and enhances low-temperature toughness, room temperature curing and corrosion resistance; the two work synergistically to take into account both mechanical properties and processability.

[0007] A core-shell powder particle dispersion is introduced into component A. The core-shell particle structure can be a rubber core (such as acrylic rubber) or a hard plastic shell (such as polymethyl methacrylate), with a particle size range of 50-200 nm, preferably 80-150 nm. During the curing process, the core-shell particles are uniformly dispersed in the epoxy resin. The rubber core absorbs impact energy, and the hard shell bonds well with the epoxy resin, achieving toughening without significantly reducing the modulus. Component B comprises the following raw materials in parts by weight: epichlorohydrin modified MXDA: 40-50 parts; PTMEG polyether modified amine: 20-30 parts; accelerator: 0.5-2 parts; filler: 15-25 parts; additives: 3-5 parts.

[0008] By modifying MXDA with epichlorohydrin, flexible hydroxypropyl segments are introduced to reduce the viscosity of the curing agent and improve its compatibility with the resin. The high strength and high heat resistance of the MXDA cured product are retained. The modified curing agent has moderate activity and a suitable pot life (45-60 minutes).

[0009] PTMEG polyether-modified amine (molecular weight 1000) introduces amine curing agent molecular chains through the soft segments of polytetrahydrofuran (PTMEG), providing molecular-level toughening effect, significantly improving the elongation at break of the cured adhesive layer, improving low-temperature toughness, and maintaining an impact strength retention rate of >80% at -40℃. It works synergistically with the main curing agent to achieve a balance between rigidity and toughness.

[0010] In a preferred embodiment of the present invention, the weight ratio of component A to component B is 100:25-40.

[0011] In a preferred embodiment of the present invention, the active diluent is selected from one or more of butyl glycidyl ether, phenyl glycidyl ether, and neopentyl glycol diglycidyl ether; the silane coupling agent is selected from γ-aminopropyltriethoxysilane or γ-glycidyl etheroxypropyltrimethoxysilane; the filler is selected from one or more of calcium carbonate, calcium sulfate, silicon powder, aluminum powder, and fiber powder, with a particle size of 800-1500 mesh; the accelerator is selected from one or a combination of 2,4,6-tris(dimethylaminomethyl)phenol and 1,8-diazabicycloundec-7-ene; the additives include defoamers and thixotropic agents; the defoamer is selected from one or more of organosilicon, polyether-modified organosilicon, or acrylate; the thixotropic agent is selected from one or more of organobentonite, hydrogenated castor oil, and fumed silica.

[0012] A composite filler system is employed, with one or more combinations of calcium carbonate, calcium sulfate, silica powder, aluminum powder, and fiber powder selected according to requirements. The fiber powder can be carbon fiber powder, glass fiber powder, or aramid fiber powder, with a length of 50-200μm and a diameter of 5-15μm. The filler undergoes surface treatment to improve the interfacial bonding force with the resin matrix, achieving multiple functions: reducing costs, regulating rheological properties, reducing shrinkage, and improving mechanical properties.

[0013] In a preferred embodiment of the present invention, the epichlorohydrin-modified MXDA is prepared by the following method: Step 1.1: Calculate on a per hundred kilogram basis, add (n+a) amounts of MXDA and c amounts of Na2CO3 / Na2SO3 compound to the reactor, where c accounts for 0.01‰~8‰ of (n+a) and n=[0~12], 2≤a≤5; Step 1.2: Heat and stir the reaction vessel, dehydrate under vacuum, control the temperature to 100~110℃, and stir to disperse; Step 1.3: Cool the reactor to 40℃~50℃, and start adding epichlorohydrin (ECH) dropwise or in batches, so that the temperature of the material in the reactor is controlled below 65℃ throughout the feeding process.

[0014] Step 1.4: After feeding is completed, maintain the temperature at 65℃±15℃ for constant temperature reaction; Step 1.5: Adjust the reaction temperature to below 40℃ and observe whether there is a heating trend. If it rises to above 50℃, continue to let it react and then let it cool naturally to 35℃~40℃.

[0015] In a preferred embodiment of the present invention, in step 1.1, the mass ratio of Na2CO3 to Na2SO3 in the Na2CO3 / Na2SO3 complex is 90:10 to 65:35; in step 1.2, the reactor is dehydrated under vacuum at 80°C, stirred and dispersed for 0.5-1.5 hours, the heating rate is controlled within 10°C / min, the stirring frequency is 20-40Hz, and the vacuum degree is -0.092MPa to -0.1MPa.

[0016] In a preferred embodiment of the present invention, in step 1.3, the rate of ECH addition is 3 kg / min to 10 kg / min; the maximum amount of ECH added in a single batch is 0.8% to 8% of the mass of MXDA material, and the interval between batches is not less than 10 min.

[0017] In a preferred embodiment of the present invention, in step 1.4, the reaction is carried out at a constant temperature for 2 to 6 hours, and in step 15, the reaction is continued for 1 to 2 hours.

[0018] Secondly, the present invention discloses a method for preparing a structural adhesive as described in the third aspect, comprising the following steps: Step 8.1 Preparation of Component A: Add bisphenol A type epoxy resin, bisphenol F type epoxy resin and reactive diluent to the reaction vessel, stir and mix evenly, add core-shell powder particle dispersion, disperse at high speed, add silane coupling agent, continue stirring, add filler, and stir and disperse under vacuum. Step 8.2, Preparation of Component B: Epichlorohydrin-modified MXDA and PTMEG polyether-modified amine are added to the reactor and stirred until homogeneous. Fillers, accelerators and additives are added and dispersed under vacuum. Step 8.3, Preparation of structural adhesive: Mix component A and component B to obtain the final product.

[0019] In a preferred embodiment of the present invention, in step 81, the high-speed dispersion conditions are: rotation speed 1000-1500 rpm, time 30-45 minutes; the stirring dispersion conditions under vacuum are: vacuum degree ≤ -0.095 MPa, time 40-60 minutes; in step 82, the stirring dispersion conditions under vacuum are: vacuum degree ≤ -0.095 MPa, time 30-40 minutes.

[0020] Thirdly, the present invention discloses the application of the structural adhesive as described in the first aspect as an adhesive material in the preparation of CFRP wind turbine blades.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The structural adhesive prepared by this invention has excellent flexibility and fatigue resistance, high strength and high adhesion, especially for interfacial bonding of CFRP materials. At the same time, it has excellent high and low temperature resistance, low sensitivity to climate environment, strong process adaptability, can be cured at room temperature or accelerated at 60-80℃, and is compatible with wind turbine blade manufacturing process to meet production efficiency requirements. Attached Figure Description

[0022] Figure 1 A process diagram for core-shell particle toughening modified epoxy resin provided by the present invention; Figure 2 This is a schematic diagram of the CFRP reinforcing rib bonding structure provided by the present invention; Figure 3 A comparison chart of curing curves of structural adhesives at different temperatures provided by this invention. Detailed Implementation

[0023] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Example 1: Preparation of epichlorohydrin-modified MXDA 1. Calculated on a per-hundred-kilogram basis, add (n+a) amounts of MXDA and c amounts of the Na2CO3 / Na2SO3 compound (compound ratio 75:25) to the reactor. The c value accounts for 4‰ of the (n+a) value, n=6, a=3.

[0026] 2. While heating and stirring, begin vacuum dehydration at 80℃, control the temperature to 100~110℃, and stir and disperse for 0.5h-1.5h. The heating rate should be controlled within 10℃ / min, the stirring frequency at 30Hz, and the vacuum degree at -0.095MPa.

[0027] 3. Turn on the cooling water and lower the temperature to between 40℃ and 50℃. Begin adding epichlorohydrin (ECH) dropwise or in batches. The dropwise ECH addition rate is 6 kg / min; for batch addition, the maximum single addition amount is 5% of the MXDA material mass, with an interval of no less than 10 minutes between batches. Control the circulating water flow rate to keep the material temperature inside the reactor below 65℃ throughout the entire feeding process.

[0028] 4. After addition, maintain a constant temperature, stir, vacuum, and control the cooling water, keeping the temperature at 65℃ and reacting in the constant temperature range for 4 hours (determine the preparation time based on the reaction amount and measured data). Stirring frequency: 30Hz; vacuum degree: -0.095MPa.

[0029] 5. Cool the water down to below 40℃ and observe if there is a temperature rise trend. If it rises to above 50℃, continue the reaction for 2 hours.

[0030] 6. Allow the material to cool naturally to 35℃~40℃, then drain completely. Store in a sealed container.

[0031] Example 2: Preparation of a high-performance structural adhesive suitable for bonding CFRP reinforcing ribs to wind turbine blades Preparation of Component A: Bisphenol A type epoxy resin (epoxy equivalent 185-192): 40 parts; Bisphenol F type epoxy resin (epoxy equivalent 165-175): 35 parts; Core-shell powder particle dispersion (butyl acrylate core or PMMA shell, average particle size 100nm): 15 parts; Neopentyl glycol diglycidyl ether: 8 parts; γ-glycidyl etheroxypropyltrimethoxysilane: 2 parts; Calcium carbonate (1250 mesh): 25 parts; Fiber powder (100μm in length, 8μm in diameter): 5 parts.

[0032] Bisphenol A type epoxy resin, bisphenol F type epoxy resin, and neopentyl glycol diglycidyl ether were added to a reaction vessel and stirred until homogeneous. Core-shell powder particle dispersion was then added and dispersed at high speed (1250 rpm, 37 minutes). γ-glycidyl etheroxypropyltrimethoxysilane was then added and stirring continued for 18 minutes. Calcium carbonate and fiber powder were added, and the mixture was dispersed under vacuum (-0.095 MPa, 50 minutes). Viscosity, fineness, and other indicators were tested. After passing the tests, the mixture was packaged. Preparation of Component B: Molecular structure of PTMEG polyether-modified amine Epichlorohydrin modified MXDA (amine hydrogen equivalent 65): 45 parts; PTMEG polyether modified amine (molecular weight 1000, amine hydrogen equivalent 120): 25 parts; Calcium sulfate (1000 mesh): 20 parts; Fumed silica (thixotropic agent): 2 parts; 2,4,6-Tris(dimethylaminomethyl)phenol: 1 part; Acrylic ester (defoamer): 1 part.

[0033] Epichlorohydrin-modified MXDA and PTMEG polyether-modified amine (molecular weight 1000, from ENOVIK, P-series product) were added to a reactor and stirred until homogeneous. Calcium sulfate, 2,4,6-tris(dimethylaminomethyl)phenol, fumed silica, and acrylate were then added. The mixture was stirred and dispersed under vacuum (-0.095 MPa) for 35 minutes. Gelation time and other indicators were tested, and the mixture was packaged after passing the tests.

[0034] Preparation of structural adhesives: Mix component A and component B evenly at a weight ratio of 100:30 to obtain the final product.

[0035] Example 3: Preparation of a high-performance structural adhesive suitable for bonding CFRP reinforcing ribs to wind turbine blades Preparation of Component A: Bisphenol A type epoxy resin (epoxy equivalent 185-192): 55 parts; Bisphenol F type epoxy resin (epoxy equivalent 165-175): 25 parts; Core-shell powder particle dispersion (butyl acrylate core or PMMA shell, average particle size 100nm): 20 parts; Phenyl glycidyl ether: 7 parts; γ-aminopropyltriethoxysilane: 5 parts; Calcium sulfate (1000 mesh): 22 parts; Fiber powder (100μm in length, 8μm in diameter): 8 parts.

[0036] Bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenyl glycidyl ether were added to a reaction vessel and stirred until homogeneous. Core-shell powder particle dispersion was then added and dispersed at high speed (1250 rpm, 37 minutes). γ-aminopropyltriethoxysilane was then added and stirring continued for 18 minutes. Calcium sulfate and fiber powder were added, and the mixture was dispersed under vacuum (-0.095 MPa, 50 minutes). Viscosity, fineness, and other indicators were tested. After passing the tests, the product was packaged. Preparation of Component B: Molecular structure of PTMEG polyether-modified amine Epichlorohydrin modified MXDA (amine hydrogen equivalent 65): 48 parts; PTMEG polyether-modified amine (molecular weight 1000, amine hydrogen equivalent 120): 21 parts; Calcium sulfate (1000 mesh): 20 parts; Organic bentonite (thixotropic agent): 3 parts; 2,4,6-Tris(dimethylaminomethyl)phenol: 1 part; Acrylic ester (defoamer): 1 part.

[0037] Epichlorohydrin-modified MXDA and PTMEG polyether-modified amine (molecular weight 1000, from ENOVIK, P-series product) were added to a reactor and stirred until homogeneous. Calcium sulfate, 2,4,6-tris(dimethylaminomethyl)phenol, organobentonite, and acrylate were then added. The mixture was stirred and dispersed under vacuum (≤-0.095MPa) for 30-40 minutes. Gelation time and other indicators were tested, and the mixture was packaged after passing the tests.

[0038] Preparation of structural adhesives: Mix component A and component B evenly at a weight ratio of 100:30 to obtain the final product.

[0039] Example 4: Preparation of a high-performance structural adhesive suitable for bonding CFRP reinforcing ribs to wind turbine blades Preparation of Component A: Bisphenol A type epoxy resin (epoxy equivalent 185-192): 65 parts; Bisphenol F type epoxy resin (epoxy equivalent 165-175): 28 parts; Core-shell powder particle dispersion (butyl acrylate core or PMMA shell, average particle size 100nm): 18 parts; Butyl glycidyl ether: 7 parts; γ-glycidyl etheroxypropyltrimethoxysilane: 5 parts; Calcium carbonate (1250 mesh): 20 parts; Fiber powder (100μm in length, 8μm in diameter): 10 parts.

[0040] Bisphenol A type epoxy resin, bisphenol F type epoxy resin, and butyl glycidyl ether were added to a reaction vessel and stirred until homogeneous. Core-shell powder particle dispersion was then added and dispersed at high speed (1250 rpm, 37 minutes). γ-glycidyl etheroxypropyltrimethoxysilane was then added and stirring continued for 18 minutes. Calcium carbonate and fiber powder were added, and the mixture was dispersed under vacuum (-0.095 MPa, 50 minutes). Viscosity, fineness, and other indicators were tested. After passing the tests, the mixture was packaged. Preparation of Component B: Molecular structure of PTMEG polyether-modified amine Epichlorohydrin modified MXDA (amine hydrogen equivalent 65): 42 parts; PTMEG polyether-modified amine (molecular weight 1000, amine hydrogen equivalent 120): 22 parts; Calcium sulfate (1000 mesh): 20 parts; Hydrogenated castor oil (thixotropic agent): 2 parts; 2,4,6-Tris(dimethylaminomethyl)phenol: 1.5 parts; Acrylic ester (defoamer): 2 parts.

[0041] Epichlorohydrin-modified MXDA and PTMEG polyether-modified amine (molecular weight 1000, from ENOVIK, P-series product) were added to a reactor and stirred until homogeneous. Calcium sulfate, 2,4,6-tris(dimethylaminomethyl)phenol, hydrogenated castor oil, and acrylate were then added. The mixture was stirred and dispersed under vacuum (≤-0.095MPa) for 30-40 minutes. Gelation time and other indicators were tested, and the mixture was packaged after passing the tests.

[0042] Preparation of structural adhesives: Mix component A and component B evenly at a weight ratio of 100:30 to obtain the final product.

[0043] Comparative Example 1 The preparation method is basically the same as in Example 2, except that the core-shell powder particle dispersion is not involved in component A.

[0044] Comparative Example 2 The preparation method is basically the same as in Example 2, except that in component B, epichlorohydrin-modified MXDA is not involved, and conventional MXDA is used.

[0045] Comparative Example 3 The preparation method is basically the same as in Example 2, except that PTMEG polyether modified amine is not involved in component B.

[0046] Comparative Example 4 The preparation method is basically the same as in Example 2, except that component B lacks epichlorohydrin-modified MXDA and PTMEG polyether-modified amine components.

[0047] Comparative Example 5 The preparation method is basically the same as in Example 2, except that in component A, 5-8 parts of core-shell powder particle dispersion are used.

[0048] Comparative Example 6 The preparation method is basically the same as in Example 2, except that in component A, 25-35 parts of core-shell powder particle dispersion are used.

[0049] Experimental Example 1 The performance of the structural adhesives prepared in Examples 2-4, Comparative Examples 1-4, and commercially available structural adhesives of the present invention was tested using the following method: The prepared structural adhesives were coated onto the surface of CFRP specimens (100×25×3mm), bonded together, and then pressurized at 0.1-0.2MPa. The specimens were cured at 80℃ for 3 hours and then left at room temperature for 7 days before performance testing. The results are shown in Table 1.

[0050] Table 1. Performance test results of structural adhesives Among them, imported rubber 1 is Spabond 435 produced by Gurit Company, and domestic rubber 1 is Techstorm 380 / 385 produced by Daosheng Tianhe Company.

[0051] As shown in Table 1, the structural adhesives prepared in Examples 2-4 of this invention exhibit stronger impact strength retention and fatigue life compared to Comparative Examples 1-6, domestic adhesives, and imported adhesives. This indicates that the addition of the core-shell powder particle dispersion, epichlorohydrin-modified MXDA, and PTMEG polyether-modified amine synergistically increases the consistency of the rigidity-toughness balance of the structural adhesive, significantly enhancing its bulk strength and adhesion. While maintaining its glass transition capability, this extends the durability and service life of wind turbine blades under extreme cold environments and load fatigue. However, it should be noted that when the amount of core-shell powder particle dispersion added is low or high, the performance of the structural adhesive decreases to some extent, indicating that the amount of core-shell powder particle dispersion can affect the performance of the structural adhesive.

[0052] Example 2: Investigating the curing effect of structural adhesive at different temperatures The structural adhesive prepared in Example 2 was applied to the surface of a CFRP specimen (100×25×3mm), bonded together, and then pressurized at 0.1-0.2 MPa. The specimens were cured at 50℃, 60℃, 70℃, and 80℃ for 25 hours, respectively. The results are as follows: Figure 3 As shown.

[0053] Depend on Figure 3 It is known that, under different medium-temperature curing temperatures and curing times, the structural adhesive of the present invention can reach above 60°C within the curing process time, meeting the requirements for use in high-temperature weather in summer; and regardless of the temperature point (above room temperature), its final curing Tg is above 70°C, exhibiting a wide range of near-complete curing capabilities and good thermodynamic application adaptability.

[0054] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A high-performance structural adhesive suitable for bonding CFRP reinforcing ribs to wind turbine blades, characterized in that, It includes component A and component B. Component A includes the following raw materials in parts by weight: bisphenol A type epoxy resin: 40-70 parts; bisphenol F type epoxy resin: 20-40 parts; core-shell powder particle dispersion: 10-20 parts; reactive diluent: 5-10 parts; silane coupling agent: 0-8 parts. Filler: 20-35 parts; Component B comprises the following raw materials in parts by weight: epichlorohydrin modified MXDA: 40-50 parts; PTMEG polyether modified amine: 20-30 parts; accelerator: 0.5-2 parts; Filler: 15-25 parts; Additives: 3-5 parts.

2. The structural adhesive according to claim 1, characterized in that, The weight ratio of component A to component B is 100:25-40.

3. The structural adhesive according to claim 1, characterized in that, The active diluent is selected from one or more of butyl glycidyl ether, phenyl glycidyl ether, and neopentyl glycol diglycidyl ether; the silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane or γ-glycidyl etheroxypropyltrimethoxysilane; the filler is selected from one or more of calcium carbonate, calcium sulfate, silica powder, aluminum powder, and fiber powder, with a particle size of 800-1500 mesh; the accelerator is selected from one or a combination of 2,4,6-tris(dimethylaminomethyl)phenol and 1,8-diazabicycloundec-7-ene; the additives include defoamers and thixotropic agents; the defoamer is selected from one or more of organosilicon, polyether-modified organosilicon, or acrylate; the thixotropic agent is selected from one or more of organobentonite, hydrogenated castor oil, and fumed silica.

4. The structural adhesive according to claim 1, characterized in that, The epichlorohydrin-modified MXDA was prepared using the following method: Step 1.1: Calculate on a per hundred kilogram basis, add (n+a) amounts of MXDA and c amounts of Na2CO3 / Na2SO3 compound to the reactor, where c accounts for 0.01‰~8‰ of (n+a) and n=[0~12], 2≤a≤5; Step 1.2: Heat and stir the reaction vessel, dehydrate under vacuum, control the temperature to 100~110℃, and stir to disperse; Step 1.3: Cool the reactor to 40℃~50℃, and start adding epichlorohydrin (ECH) dropwise or in batches, so that the temperature of the material in the reactor is controlled below 65℃ throughout the feeding process. Step 1.4: After feeding is completed, maintain the temperature at 65℃±15℃ for constant temperature reaction; Step 1.5: Adjust the reaction temperature to below 40℃ and observe whether there is a heating trend. If it rises to above 50℃, continue to let it react and then let it cool naturally to 35℃~40℃.

5. The structural adhesive according to claim 1, characterized in that, In step 1.1, the mass ratio of Na2CO3 to Na2SO3 in the Na2CO3 / Na2SO3 complex is 90:10 to 65:35; in step 1.2, the reactor is dehydrated under vacuum at 80°C, stirred and dispersed for 0.5-1.5 hours, the heating rate is controlled within 10°C / min, the stirring frequency is 20-40Hz, and the vacuum degree is -0.092MPa to -0.1MPa.

6. The structural adhesive according to claim 1, characterized in that, In step 1.3, the rate of ECH addition is 3 kg / min to 10 kg / min; the maximum amount of ECH added in a single batch is 0.8% to 8% of the mass of MXDA material, and the interval between batches is not less than 10 min.

7. The structural adhesive according to claim 1, characterized in that, In step 1.4, the reaction is carried out at a constant temperature for 2-6 hours. In step 15, the reaction is continued for 1-2 hours.

8. The method for preparing the structural adhesive according to any one of claims 1-7, characterized in that, Includes the following steps: Step 8.1 Preparation of Component A: Add bisphenol A type epoxy resin, bisphenol F type epoxy resin and reactive diluent to the reaction vessel, stir and mix evenly, add core-shell powder particle dispersion, disperse at high speed, add silane coupling agent, continue stirring, add filler, and stir and disperse under vacuum. Step 8.2, Preparation of Component B: Epichlorohydrin-modified MXDA and PTMEG polyether-modified amine are added to the reactor and stirred until homogeneous. Fillers, accelerators and additives are added and dispersed under vacuum. Step 8.3, Preparation of structural adhesive: Mix component A and component B to obtain the final product.

9. The preparation method according to claim 8, characterized in that, In step 81, the high-speed dispersion conditions are: rotation speed 1000-1500 rpm, time 30-45 minutes; the vacuum dispersion conditions are: vacuum degree ≤ -0.095 MPa, time 40-60 minutes; in step 82, the vacuum dispersion conditions are: vacuum degree ≤ -0.095 MPa, time 30-40 minutes.

10. The application of the structural adhesive as described in any one of claims 1-7 as an adhesive material in the preparation of CFRP reinforcing ribs for wind turbine blades.

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