A light-curing adhesive for wind turbine blade repair, its preparation method and application

Abstract

This invention relates to the technical field of C09J163 / 00, specifically to a light-curing adhesive for wind turbine blade repair, its preparation method, and its application. The light-curing adhesive for wind turbine blade repair comprises the following raw materials: 0-5 parts of tetrafunctional glycidylamine epoxy resin, 40-50 parts of modified epoxy polyacrylate, 20-30 parts of monofunctional acrylate, 10-20 parts of difunctional acrylate, 5-10 parts of polyfunctional acrylate, 0.5-2 parts of photoinitiator, and 0.5-2 parts of thermal initiator. The light-curing adhesive for wind turbine blade repair prepared by this invention exhibits superior mechanical properties compared to general-purpose epoxy resins. Furthermore, it can be cured using a UV lamp, reducing the curing time to 15 minutes. Verification has shown that the strength and performance of the repaired composite material reach and exceed those achieved using general-purpose epoxy resins for wind turbine blade repair, demonstrating excellent development prospects.

Description

Technical Field

[0001] This invention relates to the technical field of C09J163 / 00, specifically to a light-curing adhesive for wind turbine blade repair, its preparation method, and its application. Background Technology

[0002] Wind power generation has developed rapidly over the past two decades, and the wind turbine blades, the main component of wind turbines, have also seen rapid development. Wind turbine blades are composite materials made from epoxy resin and glass fiber through a vacuum infusion process, with lengths ranging from tens of meters to over 100 meters for offshore wind power. The typical lifespan of wind turbine blades is 20 years. Early blades are now reaching the end of their service life, and under the continuous corrosion and damage from wind, sand, and extreme weather, many blades have developed surface damage, with depths reaching 2mm to 15mm. This severely compromises the blade's strength and poses a significant challenge to the operational safety of the wind turbine. Current repair methods involve workers treating the damaged area with general-purpose epoxy resin and then applying a layer of glass fiber and epoxy resin using hand lay-up or vacuum infusion processes. This method requires heating and curing the epoxy resin, with curing times ranging from 6 to 24 hours depending on the heating temperature. The repair process is relatively inefficient and poses safety risks to repair personnel.

[0003] Chinese patent application number CN201910933580.2 discloses an engineering adhesive that can be cured by both light and heat, its preparation method and application. It can be cured by ultraviolet light or a combination of ultraviolet light and heat, which solves the limitation of bonding applications of light-shielding or semi-transparent materials, and cannot solve the curing problem by light alone.

[0004] Therefore, providing a method to improve the strength of repaired wind turbine blades and increase curing efficiency is the main technical problem that needs to be solved. Summary of the Invention

[0005] To address the above problems, the first aspect of this invention provides a photocurable adhesive for repairing wind turbine blades, the raw materials of which include: 0-5 parts of glycidyl amine type epoxy resin, 40-50 parts of modified epoxy polyacrylate, 20-30 parts of monofunctional acrylate, 10-20 parts of difunctional acrylate, 5-10 parts of polyfunctional acrylate, 0.5-2 parts of photoinitiator, and 0.5-2 parts of thermal initiator.

[0006] Preferably, the glycidylamine epoxy resin is a tetrafunctional glycidylamine epoxy resin.

[0007] The tetrafunctional glycidylamine type epoxy resin is available from Shanghai Huayi Resin Co., Ltd., model AG601.

[0008] The structural formula of the tetrafunctional glycidylamine type epoxy resin is shown in structural formula (1):

[0009]

[0010] Preferably, the raw materials for preparing the modified epoxy polyacrylate include epoxy resin and grafted monomers, wherein the epoxy equivalent of the epoxy resin is 170-200.

[0011] Furthermore, the epoxy equivalent of the epoxy resin is 180-190.

[0012] Preferably, the epoxy resin includes, but is not limited to, one or any two or more of the following: bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

[0013] Preferably, the grafting monomer is selected from one or a mixture of two of methacrylic acid and acrylic acid.

[0014] Preferably, the mass ratio of the grafted monomer to the epoxy resin is 1:(4-5.5).

[0015] Furthermore, the raw materials for preparing the modified epoxy polyacrylate include epoxy resin with an epoxy equivalent of 180-190, methacrylic acid, acrylic acid, hydroquinone, dimethyl benzylamine, and tert-butylcatechol.

[0016] Further, by weight, the raw materials for preparing the modified epoxy polyacrylate include 3500-4000 parts of epoxy resin with an epoxy equivalent of 180-190, 680-750 parts of methacrylic acid, 60-80 parts of acrylic acid, 1-2.5 parts of hydroquinone, 7-10 parts of dimethyl benzylamine, and 1-3 parts of tert-butylcatechol.

[0017] Further, by weight, the raw materials for preparing the modified epoxy polyacrylate include 3750 parts of epoxy resin with an epoxy equivalent of 180-190, 709 parts of methacrylic acid, 72 parts of acrylic acid, 1.5 parts of hydroquinone, 8.86 parts of dimethyl benzylamine, and 2 parts of tert-butylcatechol.

[0018] Preferably, the preparation method of the modified epoxy polyacrylate includes the following steps: adding a certain amount of epoxy resin, methacrylic acid, acrylic acid, hydroquinone, and dimethyl benzylamine sequentially to a reaction flask equipped with a thermometer, stirrer, and reflux condenser. After the addition is complete, the reaction system is heated to 100°C by stirring and reacted for 50-70 minutes. Then, the temperature is gradually lowered to 110-120°C and reacted for 4-6 hours. When the epoxy equivalent of the system reaches 2000-2400 and the acid value is less than 5, the temperature is lowered. When the temperature drops to 80°C, tert-butylcatechol is added, and stirring is continued until 50°C is reached. The modified epoxy polyacrylate is then discharged.

[0019] Further, the preparation method of the modified epoxy polyacrylate includes the following steps: a certain amount of epoxy resin, methacrylic acid, acrylic acid, hydroquinone and dimethyl benzylamine are added sequentially to a reaction flask equipped with a thermometer, stirrer and reflux condenser. After the addition is completed, the reaction system is heated to 100°C by stirring and reacted for 60 min. Then the temperature is gradually reduced to 110-120°C and reacted for 5 h. When the epoxy equivalent of the system reaches 2000-2400 and the acid value is less than 5, the temperature is reduced. When the temperature drops to 80°C, tert-butylcatechol is added and stirring is continued to 50°C. The modified epoxy polyacrylate is then discharged.

[0020] The method for preparing the modified epoxy polyacrylate involves mixing epoxy resin and graft monomers, then performing a ring-opening grafting reaction under the action of dimethyl benzylamine. After reaching the theoretical epoxy equivalent, the mixture is cooled to room temperature to obtain a partially ring-opened modified epoxy polyacrylate retaining 10% to 20% epoxy groups.

[0021] To improve curing efficiency, the applicant discovered during the process that modifying the epoxy resin with grafted monomers, using epoxy resins with an epoxy equivalent of 170-200, particularly 180-190, and a mass ratio of grafted monomer to epoxy resin of 1:(4-5.5), wherein the grafted monomer is selected from one or a mixture of two of methacrylic acid and acrylic acid; furthermore, a certain amount of epoxy resin, methacrylic acid, acrylic acid, hydroquinone, and dimethylbenzylamine are sequentially added to a reaction flask equipped with a thermometer, stirrer, and reflux condenser. After the addition is complete, stirring is started to react the epoxy resin. The system should be heated to 100℃ and reacted for 50-70 minutes, then gradually heated to 110-120℃ and reacted for 4-6 hours. When the epoxy equivalent of the system reaches 2000-2400 and the acid value is less than 5, the temperature should be lowered. When the temperature drops to 80℃, tert-butylcatechol should be added, and stirring should continue until 50℃ is reached. The modified epoxy polyacrylate is obtained by grafting acrylic double bonds into the epoxy molecule structure and obtaining a partially ring-opened modified epoxy polyacrylate retaining 10%~20% epoxy groups. This allows the modified epoxy polyacrylate to form a cross-linked curing structure under dual curing conditions of light and heat, improving the curing efficiency.

[0022] Preferably, the monofunctional acrylate is selected from one or more of hydroxypropyl methacrylate, hydroxyethyl methacrylate, isobornyl methacrylate, (3,3,5-trimethylcyclohexyl) methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, isobornyl acrylate, cycloaliphatic methacrylate, and dicyclopentenyl acrylate.

[0023] Furthermore, the monofunctional acrylate is at least one of hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0024] The CAS number of the hydroxypropyl acrylate is 2918-23-2.

[0025] The CAS number for the hydroxyethyl methacrylate is 868-77-9.

[0026] The CAS number of the hydroxypropyl methacrylate is 27813-02-1.

[0027] Preferably, the bifunctional acrylate is selected from one or more mixtures of 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 2-methyl-1,3-propanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, neopentanediol diacrylate, and propoxylated neopentanediol diacrylate.

[0028] Furthermore, the difunctional acrylate is at least one of propylene oxide neopentyl glycol diacrylate, dipropylene glycol diacrylate, and 1,4-butanediol diacrylate.

[0029] The CAS number of the propoxylated neopentyl glycol diacrylate is 84170-74-1.

[0030] The CAS number of the dipropylene glycol diacrylate is 57472-68-1.

[0031] The CAS number of the 1,4-butanediol diacrylate is 1070-70-8.

[0032] Preferably, the multifunctional acrylate is selected from one or more of the following: ethoxylated trimethylolpropane trimethacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and propoxylated glycerol triacrylate.

[0033] Furthermore, the multifunctional acrylate is at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and propoxylated glycerol triacrylate.

[0034] The CAS number for the trimethylolpropane triacrylate is 15625-89-5.

[0035] The CAS number of the trimethylolpropane trimethacrylate is 3290-92-4.

[0036] The CAS number for the trimethylolpropane triacrylate is 15625-89-5.

[0037] The CAS number of the propoxylated glycerol triacrylate is 52408-84-1.

[0038] Preferably, the photoinitiator is selected from one or more of the following: (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl ethyl ketone, 2,4-dihydroxybenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone, isopropylthioxanthone, benzoin dimethyl ether, and triarylsulfonium hexafluoroantimony.

[0039] Further, the photoinitiator is at least one selected from (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, benzophenone, and isopropylthioxanthrone.

[0040] The CAS number of the (2,4,6-trimethylbenzoyl)diphenylphosphine oxide is 75980-60-8.

[0041] The CAS number of the phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide is 162881-26-7.

[0042] The CAS number of the 2-hydroxy-2-methyl-1-phenylpropanone is 7473-98-5.

[0043] The CAS number of the ethyl 2,4,6-trimethylbenzoylphenylphosphonate is 84434-11-7.

[0044] The CAS number of the benzophenone is 119-61-9.

[0045] The CAS number of the isopropylthioxanthone is 5495-84-1.

[0046] Preferably, the thermal initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, aromatic amines, benzoyl peroxide, dicumyl peroxide, and tert-butyl peroxide.

[0047] Furthermore, the thermal initiator is at least one of aromatic amines and benzoyl peroxide.

[0048] To improve the tensile and flexural strength, adhesion strength to the substrate material during application, and curing efficiency of the photocurable adhesive used for wind turbine blade repair, the applicant discovered in experiments that using the modified epoxy polyacrylate prepared in this application with tetrafunctional glycidylamine epoxy resin, monofunctional acrylate, difunctional acrylate, and polyfunctional acrylate, under the action of photoinitiators and thermal initiators, can achieve higher tensile and flexural strength, as well as better adhesion to the substrate material during application. Furthermore, the curing efficiency of the photocurable adhesive is significantly improved. This is likely because the modified epoxy polyacrylate possesses acrylic double bonds and retains some epoxy groups. Acrylic double bonds cure rapidly under photocuring conditions, and... The heat generated during the curing process provides heat for the cross-linking and curing of epoxy groups, eliminating the need for further heating and achieving a dual curing structure of photothermal curing. Furthermore, the epoxy groups exhibit high bonding strength with wind turbine blades based on epoxy resin. Adding monofunctional, difunctional, and polyfunctional acrylates reduces the viscosity of the modified epoxy polyacrylate, improving its processing performance. Under the action of photoinitiators and thermal initiators, these monofunctional, difunctional, and polyfunctional acrylates further cross-link and cure with the modified epoxy polyacrylate, enhancing the tensile and flexural strength of the photocurable adhesive used for wind turbine blade repair, as well as its adhesion strength to the repair substrate material and the curing efficiency of the photocurable adhesive.

[0049] The second aspect of the present invention provides a method for preparing a photocurable adhesive for wind turbine blade repair, comprising the following steps: mixing a tetrafunctional glycidylamine epoxy resin, a modified epoxy polyacrylate, a monofunctional acrylate, a difunctional acrylate, a polyfunctional acrylate, a photoinitiator, and a thermal initiator to prepare a photocurable adhesive.

[0050] The third aspect of the present invention provides an application of a light-curing adhesive for wind turbine blade repair, wherein the light-curing adhesive for wind turbine blade repair is cured and formed under an ultraviolet light source with a wavelength of 350-420nm for 15-20 minutes during the application process.

[0051] The light-curing adhesive used for wind turbine blade repair is applied to the parts of the wind turbine that need repair using a vacuum infusion process or a hand lay-up process.

[0052] Beneficial effects

[0053] 1. In this invention, by preparing modified epoxy polyacrylic acid, the curing rate of acrylic double bonds under photocuring conditions can be achieved quickly, and the heat generated during the curing process can provide heat for the cross-linking curing of epoxy groups, eliminating the need for further heating curing and obtaining a photothermal dual-curing cross-linking structure.

[0054] 2. The light-curing adhesive for wind turbine blade repair prepared by this invention provides a convenient repair method during application, requiring no heating for curing and achieving curing and molding under light irradiation for 15-20 minutes; compared with the general epoxy repair process, the repair and curing process of general epoxy resin requires 6-24 hours.

[0055] 3. In this invention, a light-curing adhesive with high tensile strength and flexural strength is obtained by combining modified epoxy polyacrylic acid with tetrafunctional glycidylamine epoxy resin and monofunctional, difunctional, and polyfunctional acrylates.

[0056] 4. The light-curing adhesive for wind turbine blade repair prepared by the present invention has high bonding strength with the epoxy resin substrate of the wind turbine blade and can improve the bending strength of the wind turbine blade substrate after repair and molding.

[0057] 5. In this invention, by using monofunctional acrylates, difunctional acrylates, and polyfunctional acrylates in combination with modified epoxy polyacrylic acid, the viscosity of the modified epoxy polyacrylic acid can be diluted, thereby improving the processing performance of the modified epoxy polyacrylic acid.

[0058] 6. The present invention provides a light-curing adhesive for wind turbine blade repair that has superior mechanical properties compared to general epoxy resin. Furthermore, it can be cured by UV light, reducing the curing time to 15 minutes. Verification has shown that the strength and performance of the repaired composite material meet or exceed those of wind turbine blade repair using general epoxy resin, demonstrating excellent development prospects. Attached Figure Description

[0059] Figure 1 This diagram illustrates the process of applying a light-curing adhesive to uniaxial fiberglass cloth and conducting a curing experiment. Detailed Implementation

[0060] Example 1

[0061] The raw materials for preparing the modified epoxy polyacrylate, by weight, include 3750 parts of epoxy resin with an epoxy equivalent of 180-190, 709 parts of methacrylic acid, 72 parts of acrylic acid, 1.5 parts of hydroquinone, 8.86 parts of dimethyl benzylamine, and 2 parts of tert-butylcatechol.

[0062] The epoxy resin was purchased from Nan Ya Plastics Industrial Co., Ltd., and its model number is NPEL-127.

[0063] The CAS number of the methacrylic acid is 79-41-4.

[0064] The CAS number of the acrylic acid is 79-10-7.

[0065] The CAS number of the hydroquinone is 123-31-9.

[0066] The CAS number of the dimethylbenzylamine is 585-32-0.

[0067] The CAS number of the tert-butylcatechol is 27213-78-1.

[0068] The method for preparing the modified epoxy polyacrylate includes the following steps: 3750 parts of epoxy resin with an epoxy equivalent of 180-190, 709 parts of methacrylic acid, 72 parts of acrylic acid, 1.5 parts of hydroquinone, and 8.86 parts of dimethyl benzylamine are added sequentially to a reaction flask equipped with a thermometer, stirrer, and reflux condenser. After the addition is complete, the reaction system is heated to 100°C by stirring and reacted for 60 minutes. The temperature is then gradually lowered to 110°C and reacted for 5 hours. When the epoxy equivalent of the system reaches 2000-2400 and the acid value is less than 5 mg KOH / g, the temperature is lowered. When the temperature drops to 80°C, 2 parts of tert-butylcatechol are added, and stirring is continued until 50°C is reached. The modified epoxy polyacrylate is then discharged.

[0069] The acid value was tested according to the standard method of GB / T 6743-2008.

[0070] Example 2

[0071] The first aspect of this embodiment provides a light-curing adhesive for repairing wind turbine blades, the raw materials of which include: 2 parts of tetrafunctional glycidylamine epoxy resin, 48 parts of modified epoxy polyacrylate, 25 parts of monofunctional acrylate, 15 parts of difunctional acrylate, 10 parts of polyfunctional acrylate, 1 part of photoinitiator, and 1 part of thermal initiator.

[0072] The tetrafunctional glycidylamine epoxy resin was purchased from Shanghai Huayi Resin Co., Ltd., and its model number is AG601.

[0073] The modified epoxy polyacrylate is the modified epoxy polyacrylate prepared in Example 1.

[0074] The monofunctional acrylate is hydroxypropyl acrylate.

[0075] The CAS number of the hydroxypropyl acrylate is 2918-23-2.

[0076] The difunctional acrylate is propoxylated neopentyl glycol diacrylate.

[0077] The CAS number of the propoxylated neopentyl glycol diacrylate is 84170-74-1.

[0078] The multifunctional acrylate is trimethylolpropane triacrylate.

[0079] The CAS number for the trimethylolpropane triacrylate is 15625-89-5.

[0080] The photoinitiator is a mixture of ethyl 2,4,6-trimethylbenzoylphenylphosphonate and isopropylthioxanthone in a weight ratio of 1:1.

[0081] The CAS number of the ethyl 2,4,6-trimethylbenzoylphenylphosphonate is 84434-11-7.

[0082] The CAS number of the isopropylthioxanthone is 5495-84-1.

[0083] The thermal initiator is an aromatic amine.

[0084] The aromatic amine was purchased from Shanghai Huayi Resin Co., Ltd., and its model number is AMI-1.

[0085] The second aspect of this embodiment provides a method for preparing a photocurable adhesive for wind turbine blade repair, comprising the following steps: mixing a tetrafunctional glycidylamine epoxy resin, a modified epoxy polyacrylate, a monofunctional acrylate, a difunctional acrylate, a polyfunctional acrylate, a photoinitiator, and a thermal initiator to prepare a photocurable adhesive.

[0086] The third aspect of this embodiment provides an application of a photocurable adhesive for wind turbine blade repair. In the application process, the photocurable adhesive for wind turbine blade repair, by weight percentage, consists of 38% of the photocurable adhesive for wind turbine blade repair prepared in this embodiment and 62% of uniaxial fiberglass cloth. The photocurable adhesive is applied to the surface of the uniaxial fiberglass cloth using a vacuum induction process and then cured under an ultraviolet light source with a wavelength of 395nm for 15 minutes.

[0087] The energy density of the ultraviolet light source irradiating the surface of the photocurable adhesive is 40 mw / cm². 2 .

[0088] The uniaxial fiberglass cloth has a specification of 1250g / m². 2 The model number is E8-UD1250-390, and the manufacturer is Zhejiang Hengshi Fiber Base Co., Ltd.

[0089] The processing steps of the vacuum induction process include:

[0090] A1. Clean the mold, and then apply a release agent to the surface of the mold;

[0091] A2. Lay two layers of E8-UD1250-390 glass fiber reinforcement material on the surface of the mold. After the reinforcement material is laid, use scissors to cut off the excess fibers.

[0092] A3. Cover the entire glass fiber reinforced material with the release cloth, leaving about 1mm extra at the edge of the glass fiber reinforced material;

[0093] A4. Lay a flow guide net on the surface of the release cloth, with the flow guide net about 3-5cm away from the glass fiber reinforced material, that is, the size of the flow guide net is slightly smaller than the glass fiber reinforced material;

[0094] A5. Place the solenoid in the corresponding position in the mold cavity according to the pre-designed flow channel as the resin flow channel and vacuum tube, and pass the silicone nozzle through the solenoid;

[0095] A6. After the pipeline is laid out, a vacuum bag film is laid on the surface. During the laying process, the middle section of the four sides is overlapped with sealing tape to form a raised shape to prevent the vacuum bag film from bridging.

[0096] A7. Insert the guide tube into the silicone connector of the resin and the vacuum end, and seal it with sealant;

[0097] A8. Secure the inlet tube of the UV-curing adhesive with a clamp to ensure a sealed environment. Turn on the vacuum pump to remove the air from the vacuum bag, then temporarily turn off the vacuum pump and clamp the inlet tube. After half an hour, ensure the vacuum pump pointer does not change.

[0098] A9. Keep the vacuum pump running and gently unscrew the clamp on the UV-curable adhesive delivery tube. The UV-curable adhesive will be drawn into the delivery tube and begin to flow. When the UV-curable adhesive reaches the UV-curable adhesive collector, close the delivery tube at the inlet end with the clamp to stop the flow.

[0099] Example 3

[0100] The first aspect of this embodiment provides a light-curing adhesive for repairing wind turbine blades, the raw materials of which include: 5 parts of tetrafunctional glycidylamine epoxy resin, 50 parts of modified epoxy polyacrylate, 20 parts of monofunctional acrylate, 15 parts of difunctional acrylate, 10 parts of polyfunctional acrylate, 1 part of photoinitiator, and 0.5 parts of thermal initiator.

[0101] The tetrafunctional glycidylamine epoxy resin was purchased from Shanghai Huayi Resin Co., Ltd., and its model number is AG601.

[0102] The modified epoxy polyacrylate is the modified epoxy polyacrylate prepared in Example 1.

[0103] The monofunctional acrylate is hydroxyethyl methacrylate.

[0104] The CAS number for the hydroxyethyl methacrylate is 868-77-9.

[0105] The difunctional acrylate is dipropylene glycol diacrylate.

[0106] The CAS number of the dipropylene glycol diacrylate is 57472-68-1.

[0107] The multifunctional acrylate is trimethylolpropane trimethacrylate.

[0108] The CAS number of the trimethylolpropane trimethacrylate is 3290-92-4.

[0109] The photoinitiator is a mixture of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropanone in a weight ratio of 1:1.

[0110] The CAS number of the phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide is 162881-26-7.

[0111] The CAS number of the 2-hydroxy-2-methyl-1-phenylpropanone is 7473-98-5.

[0112] The thermal initiator is benzoyl peroxide.

[0113] The CAS number of the benzoyl peroxide is 94-36-0.

[0114] The second aspect of this embodiment provides a method for preparing a photocurable adhesive for wind turbine blade repair, comprising the following steps: mixing a tetrafunctional glycidylamine epoxy resin, a modified epoxy polyacrylate, a monofunctional acrylate, a difunctional acrylate, a polyfunctional acrylate, a photoinitiator, and a thermal initiator to prepare a photocurable adhesive.

[0115] The third aspect of this embodiment provides an application of a photocurable adhesive for wind turbine blade repair. In the application process, the photocurable adhesive for wind turbine blade repair, by weight percentage, consists of 38% of the photocurable adhesive for wind turbine blade repair prepared in this embodiment and 62% of uniaxial fiberglass cloth. The photocurable adhesive is applied to the surface of the uniaxial fiberglass cloth using a vacuum induction process and then cured under an ultraviolet light source with a wavelength of 395nm for 15 minutes.

[0116] The processing steps of the vacuum induction process are the same as in Example 2.

[0117] The energy density of the ultraviolet light source irradiating the surface of the photocurable adhesive is 40 mw / cm². 2 .

[0118] The uniaxial fiberglass cloth has a specification of 1250g / m². 2 The model number is E8-UD1250-390, and the manufacturer is Zhejiang Hengshi Fiber Base Co., Ltd.

[0119] Example 4

[0120] The first aspect of this embodiment provides a light-curing adhesive for repairing wind turbine blades, the raw materials of which include: 45 parts of modified epoxy polyacrylate, 25 parts of monofunctional acrylate, 20 parts of difunctional acrylate, 10 parts of polyfunctional acrylate, and 1 part of photoinitiator.

[0121] The modified epoxy polyacrylate is the modified epoxy polyacrylate prepared in Example 1.

[0122] The monofunctional acrylate is hydroxypropyl methacrylate.

[0123] The CAS number of the hydroxypropyl methacrylate is 27813-02-1.

[0124] The bifunctional acrylate is a mixture of 1,4-butanediol diacrylate and propoxylated neopentyl glycol diacrylate in a weight ratio of 1:1.

[0125] The CAS number of the 1,4-butanediol diacrylate is 1070-70-8.

[0126] The CAS number of the propoxylated neopentyl glycol diacrylate is 84170-74-1.

[0127] The multifunctional acrylate is a mixture of trimethylolpropane triacrylate and propoxylated glycerol triacrylate in a weight ratio of 1:1.

[0128] The CAS number for the trimethylolpropane triacrylate is 15625-89-5.

[0129] The CAS number of the propoxylated glycerol triacrylate is 52408-84-1.

[0130] The photoinitiator is a mixture of ethyl 2,4,6-trimethylbenzoylphenylphosphonate and benzophenone in a weight ratio of 1:1.

[0131] The CAS number of the ethyl 2,4,6-trimethylbenzoylphenylphosphonate is 84434-11-7.

[0132] The CAS number of the benzophenone is 119-61-9.

[0133] The second aspect of this embodiment provides a method for preparing a photocurable adhesive for wind turbine blade repair, comprising the following steps: mixing modified epoxy polyacrylate, monofunctional acrylate, difunctional acrylate, polyfunctional acrylate, and a photoinitiator to prepare a photocurable adhesive.

[0134] The third aspect of this embodiment provides an application of a photocurable adhesive for wind turbine blade repair. In the application process, the photocurable adhesive for wind turbine blade repair is prepared by weight percentage, consisting of 40% of the photocurable adhesive and 60% of uniaxial fiberglass cloth. The photocurable adhesive is applied to the surface of the uniaxial fiberglass cloth using a hand lay-up process and then cured under a 395nm ultraviolet light source for 15 minutes.

[0135] The energy density of the ultraviolet light source irradiating the surface of the photocurable adhesive is 40 mw / cm². 2 .

[0136] The uniaxial fiberglass cloth has a specification of 1250g / m². 2 The model number is E8-UD1250-390, and the manufacturer is Zhejiang Hengshi Fiber Base Co., Ltd.

[0137] The hand lay-up process includes the following steps:

[0138] S1. Clean the mold, and then apply a release agent to the surface of the mold;

[0139] S2. Pour UV-cured adhesive onto the mold surface, roll it flat with a roller, and lay one layer of E8-UD1250-390 glass fiber reinforced material. After rolling it evenly, repeat the operation once more until two layers of E8-UD1250-390 glass fiber reinforced material are laid.

[0140] S3. Cover the surface with PET film.

[0141] Comparative Example 1

[0142] The conventional bisphenol A type epoxy resin for blade repair is used instead of the light-curing adhesive for wind turbine blade repair prepared in this application.

[0143] The bisphenol A epoxy resin used for conventional blade repair was purchased from Nan Ya Plastics Industrial Co., Ltd., model NPEL-128.

[0144] This embodiment provides the application of conventional bisphenol A epoxy resin for blade repair. In the application process, 40 parts of conventional bisphenol A epoxy resin and 60 parts of uniaxial fiberglass cloth are taken by weight. The conventional bisphenol A epoxy resin is applied to the surface of the uniaxial fiberglass cloth using a hand lay-up process, and then cured by heating at 65°C for 2 hours and at 75°C for 4 hours.

[0145] The uniaxial fiberglass cloth has a specification of 1250g / m². 2 The model number is E8-UD1250-390, and the manufacturer is Zhejiang Hengshi Fiber Base Co., Ltd.

[0146] The processing steps of the hand lay-up process are the same as in Example 4.

[0147] Performance testing

[0148] I. Performance Testing of UV-cured Adhesives Used for Wind Turbine Blade Repair

[0149] The light-curing adhesives for wind turbine blade repair prepared in Examples 2-4 were compared with conventional bisphenol A epoxy resin for blade repair as comparative examples. Tensile strength, tensile modulus, flexural strength, and flexural modulus were tested. The test results are shown in Table 1.

[0150] Table 1

[0151]

[0152] II. Performance Testing of UV-cured Adhesives for Wind Turbine Blade Repair

[0153] The photocurable adhesives for wind turbine blade repair prepared in Examples 2-4 and conventional bisphenol A epoxy resin for blade repair were used as comparative examples and applied to uniaxial fiberglass cloth under different curing conditions. The 90° tensile strength, 0° flexural strength, interlaminar shear strength, and lap shear strength of the cured uniaxial fiberglass cloth were tested, and the test results are shown in Table 2. The process of applying the photocurable adhesive to uniaxial fiberglass cloth and carrying out the curing experiment is described in [link to experiment]. Figure 1 .

[0154] Table 2

[0155]

Claims

1. A light-curing adhesive for repairing wind turbine blades, characterized in that, The raw materials for its preparation include: 2-5 parts of glycidyl amine type epoxy resin, 40-50 parts of modified epoxy polyacrylate, 20-30 parts of monofunctional acrylate, 10-20 parts of difunctional acrylate, 5-10 parts of polyfunctional acrylate, 0.5-2 parts of photoinitiator, and 0.5-2 parts of thermal initiator. The raw materials for preparing the modified epoxy polyacrylate include 3500-4000 parts of epoxy resin with an epoxy equivalent of 180-190, 680-750 parts of methacrylic acid, 60-80 parts of acrylic acid, 1-2.5 parts of hydroquinone, 7-10 parts of dimethyl benzylamine, and 1-3 parts of tert-butylcatechol. The method for preparing the modified epoxy polyacrylate includes the following steps: epoxy resin, methacrylic acid, acrylic acid, hydroquinone, and dimethyl benzylamine are added sequentially to a reaction flask equipped with a thermometer, stirrer, and reflux condenser. After the addition is complete, the reaction system is heated to 100°C by stirring and reacted for 60 minutes. Then, the temperature is gradually lowered to 110-120°C and reacted for 5 hours. When the epoxy equivalent of the system reaches 2000-2400 and the acid value is less than 5, the temperature is lowered. When the temperature drops to 80°C, tert-butylcatechol is added, and stirring is continued until 50°C. The modified epoxy polyacrylate is then discharged. The glycidylamine type epoxy resin is a tetrafunctional glycidylamine type epoxy resin. The thermal initiator is an aromatic amine or benzoyl peroxide.

2. The light-curing adhesive for wind turbine blade repair as described in claim 1, characterized in that, The monofunctional acrylate is selected from one or more of the following: hydroxypropyl methacrylate, hydroxyethyl methacrylate, isobornyl methacrylate, (3,3,5-trimethylcyclohexyl) methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, isobornyl acrylate, and dicyclopentenyl acrylate.

3. The light-curing adhesive for wind turbine blade repair as described in claim 1, characterized in that, The bifunctional acrylate is selected from one or more of the following: 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 2-methyl-1,3-propanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, neopentanediol diacrylate, and propoxylated neopentanediol diacrylate.

4. The light-curing adhesive for wind turbine blade repair as described in claim 1, characterized in that, The multifunctional acrylate is selected from one or more of the following: ethoxylated trimethylolpropane trimethacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and propoxylated glycerol triacrylate.

5. The light-curing adhesive for wind turbine blade repair as described in claim 1, characterized in that, The photoinitiator is selected from one or more of the following: (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl ethyl ketone, 2,4-dihydroxybenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone, isopropylthioxanthone, benzoin dimethyl ether, and triarylsulfonium hexafluoroantimony.

6. A method for preparing a light-curing adhesive for wind turbine blade repair as described in any one of claims 1-5, characterized in that, Includes the following steps: A photocurable adhesive is prepared by mixing a tetrafunctional glycidylamine epoxy resin, a modified epoxy polyacrylate, a monofunctional acrylate, a difunctional acrylate, a polyfunctional acrylate, a photoinitiator, and a thermal initiator.

7. The application of a light-curing adhesive for wind turbine blade repair as described in any one of claims 1-5, characterized in that, The light-curing adhesive used for wind turbine blade repair is cured and molded under an ultraviolet light source with a wavelength of 350-420nm for 15-20 minutes during application.

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