A wind power blade regenerative composite material and a preparation method and application thereof

Abstract

The application provides a wind power blade regenerated composite material and a preparation method and application thereof. The method provided by the application is characterized in that: first, retired wind power blade particles are mixed with a compounded solvent and then subjected to soaking treatment, so as to dissolve low-molecular-weight resins and imperfect three-dimensional network crosslinking structures in the retired wind power blade particles by using the compounded solvent; then, the surface of bare glass fibers is modified by using a gamma-glycidoxypropyltrimethoxysilane solution, so that the glass fibers have epoxy group active sites; then, an epoxy resin system is infiltrated and filled into the premixing material which has both pores and epoxy group active sites; then, hot pressing is performed; the pores of the three-dimensional network structure are physically combined with the epoxy resin, and the network structure is anchored together; the surface-modified glass fibers are chemically combined with the epoxy resin; and through the physical and chemical combination, the wind power blade regenerated composite material has excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade materials technology, and in particular to a recycled composite material for wind turbine blades, its preparation method, and its application. Background Technology

[0002] Currently, theoretically feasible recycling technologies for decommissioned wind turbine blades mainly include physical recycling, thermal recycling, and chemical recycling. Physical recycling involves finely cutting decommissioned wind turbine blades into specific shapes to utilize the residual properties of the materials themselves; or processing the blades through cutting, tearing, crushing, or sorting for use as reinforcement or filler. While this physical recycling process is simple and widely applicable, it is not thorough, and the recovered products have low economic value. Thermal recycling involves burning decommissioned wind turbine blades to generate electricity; or, based on energy utilization, separating and recycling inorganic materials such as fiberglass. The advantages of thermal recycling are thorough disposal and relatively mature technology, but the resource utilization rate of incineration is low, and at present, the input and output are disproportionate, resulting in low economic value. Chemical recycling uses chemical degradation to separate the resin matrix from the fiberglass in decommissioned wind turbine blades, recovering both resin and fiberglass. However, chemical recycling technology is immature, separating the resin matrix from the fiberglass is difficult, the use of compound solvents leads to significant environmental pollution, and the recycling efficiency and economics need improvement. Summary of the Invention

[0003] The purpose of this invention is to provide a recycled composite material for wind turbine blades, its preparation method, and its application. The method provided by this invention is simple, economically valuable, thoroughly recyclable, and has low environmental pollution. The resulting recycled composite material for wind turbine blades has excellent mechanical properties and can be used as a type of engineered wood product in various application scenarios.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing recycled composite materials for wind turbine blades, comprising the following steps:

[0006] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles;

[0007] (2) After mixing the decommissioned wind turbine blade particles obtained in step (1) with the compound solvent, the particles are soaked and ultrasonically treated in sequence to obtain a premix with a porous structure and exposed glass fiber. The premix with a porous structure and exposed glass fiber accounts for 80-95% of the mass of the decommissioned wind turbine blade particles.

[0008] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in γ-glycidyl etheroxypropyltrimethoxysilane solution to modify the surface of the exposed glass fiber in the premix with porous structure and exposed glass fiber, so as to obtain a premix with both porous structure and epoxy group active sites.

[0009] The volume concentration of the γ-glycidyl etheroxypropyltrimethoxysilane solution is 0.5-1%;

[0010] (4) The premixed material with both pores and epoxy group active sites obtained in step (3) is mixed with the liquid epoxy resin system and impregnated and filled to obtain the mixture.

[0011] (5) The mixture obtained in step (4) is hot-pressed to obtain a wind turbine blade recycled composite material.

[0012] Preferably, by weight, the components of the compound solvent in step (2) include: 10-20 parts of resorcinol, 10-20 parts of N,N-dimethylformamide, 10-20 parts of N-methylpyrrolidone, 20-30 parts of chloroform, 20-30 parts of benzyl alcohol and 10-20 parts of acetone.

[0013] Preferably, in step (2), the ratio of the mass of the decommissioned wind turbine blade particles to the volume of the compound solvent is 1 g: (4~5) mL.

[0014] Preferably, the surface modification in step (3) is performed at room temperature; the surface modification time is 30~50 min.

[0015] Preferably, the liquid epoxy resin system in step (4) includes liquid epoxy resin, epoxy reactive diluent, curing agent and accelerator; the mass ratio of liquid epoxy resin, epoxy reactive diluent, curing agent and accelerator is 100: (10~30): (3~10): (1~5).

[0016] Preferably, in step (4), the mass ratio of the premixed material with both pores and epoxy group active sites to the liquid epoxy resin is (5~9):(1~5).

[0017] Preferably, in step (4), the liquid epoxy resin includes one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and bisphenol F type epoxy resin; the epoxy reactive diluent includes one or more of butyl glycidyl ether, phenyl glycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and glycerol triglycidyl ether; the curing agent is a latent curing agent; and the accelerator is an organic urea accelerator.

[0018] Preferably, the temperature of hot pressing in step (5) is 140~150℃; the pressure of hot pressing is 5~10MPa; and the heat preservation and pressure holding time of hot pressing is 20~30min.

[0019] The present invention also provides a wind turbine blade regenerated composite material prepared by the preparation method described in the above technical solution.

[0020] The present invention also provides the application of the wind turbine blade recycled composite material described in the above technical solution as a type of engineered wood panel.

[0021] This invention provides a method for preparing a recycled composite material for wind turbine blades, comprising the following steps: pulverizing retired wind turbine blades to obtain retired wind turbine blade particles. This invention increases the contact area between the retired wind turbine blade particles and the compounded solvent by pulverizing the retired wind turbine blades. After mixing the retired wind turbine blade particles with the compounded solvent, the mixture undergoes sequential soaking and ultrasonic treatment. Soaking softens some of the resin in the retired wind turbine blade particles, while ultrasonic treatment utilizes ultrasound to promote the dissolution of the softened resin, thereby forming a rich porous structure and exposing some of the glass fibers in the retired wind turbine blade particles, resulting in a premix with a porous structure and exposed glass fibers. This application limits the mass percentage of the premix with a porous structure and exposed glass fibers to 80-95% of the mass of the retired wind turbine blade particles. This prevents insufficient dissolution of the retired wind turbine blade particles, which would result in too few pores, and also prevents excessive dissolution of the retired wind turbine blade particles, which would lead to excessively low strength in the prepared recycled wind turbine blade composite material. This invention involves immersing a premix containing porous structures and exposed glass fibers in a solution of γ-glycidyl etheroxypropyltrimethoxysilane to modify the surface of the exposed glass fibers. This modification allows for the application of γ-glycidyl etheroxypropyltrimethoxysilane to the exposed glass fiber surface, creating active sites and resulting in a premix possessing both porous structures and epoxy group active sites. This premix is ​​then mixed with a liquid epoxy resin system, followed by an impregnation and filling process to incorporate the liquid epoxy resin. The resin system fully impregnates and fills the pores of the premix, which contains both pores and epoxy group active sites. The resulting mixture is then hot-pressed. The epoxy group active sites in the premix participate in the thermosetting reaction of the liquid epoxy resin system. The pores of the three-dimensional network structure are physically bonded to the epoxy resin, anchored together through the network structure. The glass fiber with surface-modified active sites is chemically bonded to the epoxy resin. This combination of physical anchoring and chemical bonding results in excellent mechanical properties in the wind turbine blade recycled composite material. Furthermore, because this invention utilizes a liquid epoxy resin system to impregnate and fill the premix, which contains both pores and epoxy group active sites, no new impurities are introduced. This allows the wind turbine blade recycled composite material prepared using this method to be recycled again after use, significantly reducing solid waste generation and lowering the production cost of the wind turbine blade recycled composite material.

[0022] The method provided by this invention utilizes a compound solvent to dissolve the low molecular weight resin in decommissioned wind turbine blade particles during the soaking process, and also dissolves the imperfect three-dimensional network cross-linking structure within the resin of the decommissioned wind turbine blade particles. These dissolved products precipitate into the compound solvent, causing pores to form inside the resin of the decommissioned wind turbine blade particles and exposing some glass fibers. Meanwhile, the epoxy resin with a complete three-dimensional network structure in the decommissioned wind turbine blade particles remains insoluble. These insoluble three-dimensional network structures give the premixed particles a rich network structure, which is beneficial for the γ-glycidyl etheroxypropyltrimethoxysilane solution to surface modify the exposed glass fibers in the pores of the premix, giving them epoxy group active sites. It is also beneficial for the liquid epoxy resin to fully impregnate into the network structure when mixed with the liquid epoxy resin system. With hot pressing, the epoxy group active sites in the premix participate in the thermosetting reaction of the liquid epoxy resin system. The pores of the three-dimensional network structure are chemically bonded to the epoxy resin, and anchored together through the network structure, giving the wind turbine blade recycled composite material excellent mechanical properties. Furthermore, the solvent compounded by the method provided in this invention can be recycled and reused, exhibiting good environmental friendliness. The results of the examples show that the regenerated wind turbine blade composite material prepared by this invention has a tensile strength higher than 81.5 MPa, a flexural strength higher than 130.5 MPa, and an impact strength higher than 40.6 J / cm². 2 It has a Tg higher than 119.4℃ and a thermal decomposition temperature higher than 348.3℃, exhibiting excellent mechanical properties and high-temperature resistance. Detailed Implementation

[0023] This invention provides a method for preparing recycled composite materials for wind turbine blades, comprising the following steps:

[0024] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles;

[0025] (2) After mixing the decommissioned wind turbine blade particles obtained in step (1) with the compound solvent, the particles are soaked and ultrasonically treated in sequence to obtain a premix with a porous structure and exposed glass fiber. The premix with a porous structure and exposed glass fiber accounts for 80-95% of the mass of the decommissioned wind turbine blade particles.

[0026] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in γ-glycidyl etheroxypropyltrimethoxysilane solution to modify the surface of the exposed glass fiber in the premix with porous structure and exposed glass fiber, so as to obtain a premix with both porous structure and epoxy group active sites.

[0027] The volume concentration of the γ-glycidyl etheroxypropyltrimethoxysilane solution is 0.5-1%;

[0028] (4) The premixed material with both pores and epoxy group active sites obtained in step (3) is mixed with the liquid epoxy resin system and impregnated and filled to obtain the mixture.

[0029] (5) The mixture obtained in step (4) is hot-pressed to obtain a wind turbine blade recycled composite material.

[0030] This invention involves pulverizing retired wind turbine blades to obtain retired wind turbine blade particles.

[0031] The present invention does not have any special limitation on the source of the retired wind turbine blades, and any retired wind turbine blades that can be obtained by those skilled in the art can be used.

[0032] The present invention does not specifically limit the crushing method. Any conventional crushing method can be used to crush the decommissioned wind turbine blades to the required particle size range.

[0033] In this invention, the particle size of the decommissioned wind turbine blade particles is preferably 0.2~2 mm, more preferably 0.5~1.5 mm. By controlling the particle size of the decommissioned wind turbine blade particles within the above range, this invention allows for a larger contact area with the compounded solvent, which is more conducive to the complete dissolution of the compounded solvent and the formation of a porous three-dimensional network structure.

[0034] After obtaining the decommissioned wind turbine blade particles, the present invention mixes the decommissioned wind turbine blade particles with a compound solvent, and then performs soaking treatment and ultrasonic treatment in sequence to obtain a premix with a porous structure and exposed glass fiber.

[0035] In this invention, the components of the compound solvent, by weight, preferably include: 10-20 parts resorcinol, 10-20 parts N,N-dimethylformamide, 10-20 parts N-methylpyrrolidone, 20-30 parts chloroform, 20-30 parts benzyl alcohol, and 10-20 parts acetone. The compound solvent components used in this invention exhibit good solubility for the low molecular weight resin and the imperfect three-dimensional network cross-linked structure within the resin in decommissioned wind turbine blade particles.

[0036] The components of the compound solvent provided by the present invention preferably include 10-20 parts of resorcinol. As one embodiment of the present invention, the weight parts of the resorcinol may be 10 parts, 15 parts, or 20 parts.

[0037] Based on 10-20 parts by weight of resorcinol, the components of the compound solvent provided by the present invention preferably include 10-20 parts by weight of N,N-dimethylformamide. As one embodiment of the present invention, the N,N-dimethylformamide may be 10, 15, or 20 parts by weight.

[0038] Based on a resorcinol weight of 10-20 parts, the components of the compound solvent provided by the present invention preferably include 10-20 parts of N-methylpyrrolidone. As one embodiment of the present invention, the N-methylpyrrolidone weight can be 10 parts, 15 parts, or 20 parts.

[0039] Based on 10-20 parts by weight of resorcinol, the components of the compound solvent provided by the present invention preferably include 20-30 parts by weight of chloroform. As one embodiment of the present invention, the chloroform may be 20, 25, or 30 parts by weight.

[0040] Based on a resorcinol weight of 10-20 parts, the components of the compound solvent provided by the present invention preferably include 20-30 parts of benzyl alcohol. As one embodiment of the present invention, the benzyl alcohol weight can be 20 parts, 25 parts, or 30 parts.

[0041] Based on a resorcinol weight of 10-20 parts, the components of the compound solvent provided by the present invention preferably include 10-20 parts of acetone. As one embodiment of the present invention, the weight of the acetone may be 10 parts, 15 parts, or 20 parts.

[0042] In an embodiment of the present invention, the method for preparing the compound solvent preferably includes: adding resorcinol to a mixed solution of N,N-dimethylformamide and N-methylpyrrolidone, and then mechanically stirring for 10 min under ventilation to obtain Q1; mixing chloroform, benzyl alcohol and acetone, and mechanically stirring for 5 min under ventilation to obtain Q2; and mixing the solutions of Q1 and Q2, and mechanically stirring for 10 min under ventilation to obtain the compound solvent.

[0043] In this invention, the preferred ratio of the mass of the decommissioned wind turbine blade particles to the volume of the compound solvent is 1 g: (4~5) mL, more preferably 1 g: 5 mL. By controlling the ratio of the mass of the decommissioned wind turbine blade particles to the volume of the compound solvent within the above range, this invention ensures that the decommissioned wind turbine blade particles are completely immersed in the compound solvent.

[0044] The present invention does not have any particular limitation on the method of mixing the decommissioned wind turbine blade particles with the compound solvent; it is sufficient to mix the decommissioned wind turbine blade particles with the compound solvent evenly.

[0045] In this invention, the soaking treatment is preferably carried out at room temperature, the soaking temperature is preferably 23-25°C, and the soaking time is preferably 6-10 hours, more preferably 8-10 hours. This invention softens some of the resin in the particles of decommissioned wind turbine blades through the soaking treatment.

[0046] In this invention, the ultrasonic power is preferably 25~40KHz, more preferably 30~35KHz; the ultrasonic duration is preferably 1~2h. Through ultrasonic treatment, the cavitation effect generated by the ultrasound promotes the dissolution of low molecular weight resin in decommissioned wind turbine blade particles by the compound solvent, and dissolves the imperfect three-dimensional network cross-linked structure within the resin of the decommissioned wind turbine blade particles. The resin portion with a complete three-dimensional network structure only swells slightly and is almost unaffected. The resulting premix has a structural feature where pores are distributed irregularly within the complete three-dimensional network cross-linked structure, and the pores contain exposed glass fibers (referred to as glass fibers).

[0047] The present invention preferably performs solid-liquid separation on the system obtained by the soaking treatment to obtain a premix and solution with a porous structure and exposed glass fibers.

[0048] In this invention, the premix with a porous structure and exposed glass fiber accounts for 80-95% of the mass percentage of the decommissioned wind turbine blade particles. As one embodiment of this invention, the mass percentage of the premix with a porous structure and exposed glass fiber in the decommissioned wind turbine blade particles can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%. By controlling the mass percentage of the premix with a porous structure and exposed glass fiber in the decommissioned wind turbine blade particles within the above range, this invention enables the solubility of the decommissioned wind turbine blade particles to be controlled at 15-20%, thereby giving the premix particles a rich network porous structure.

[0049] In this invention, the solution is preferably recycled and reused for soaking treatment of the next batch of decommissioned wind turbine blade particles. The method provided by this invention can recycle the solution more than five times, reducing the amount of waste liquid and exhibiting good environmental friendliness.

[0050] After obtaining a premix with a porous structure and exposed glass fibers, the present invention immerses the premix with a porous structure and exposed glass fibers in a γ-glycidyl etheroxypropyltrimethoxysilane solution to modify the surface of the exposed glass fibers in the premix with a porous structure and exposed glass fibers, thereby obtaining a premix with both porous structure and epoxy group active sites.

[0051] In this invention, the volume concentration of the γ-glycidyl etheroxypropyltrimethoxysilane solution is 0.5% to 1%. As one embodiment of this invention, the volume concentration of the γ-glycidyl etheroxypropyltrimethoxysilane solution can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In this invention, the γ-glycidyl etheroxypropyltrimethoxysilane solution is preferably a γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution.

[0052] In an embodiment of the present invention, the mass ratio of the premix having a porous structure and exposed glass fibers to the volume ratio of the γ-glycidyl etheroxypropyltrimethoxysilane solution can be 1 g: 4 mL.

[0053] In this invention, the surface modification is preferably performed at room temperature, more preferably at 23-25°C; the surface modification time is preferably 30-50 min, more preferably 30-40 min. Through surface modification, this invention enables the dehydration condensation of γ-glycidoxypropyltrimethoxysilane on the exposed glass fiber surface within the pores of the premix, thereby imbuing it with epoxy group active sites.

[0054] The present invention preferably performs solid-liquid separation on the system obtained by the surface modification to obtain a premix with both pores and epoxy group active sites.

[0055] After obtaining a premixed material with both porous and epoxy group active sites, the present invention mixes the premixed material with a liquid epoxy resin system and performs impregnation and filling treatment to obtain a mixture.

[0056] In this invention, the liquid epoxy resin system preferably includes liquid epoxy resin, epoxy reactive diluent, curing agent and accelerator.

[0057] In this invention, the liquid epoxy resin preferably comprises one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and bisphenol F type epoxy resin. In this invention, the epoxy value of the liquid bisphenol A type epoxy resin is preferably 0.45~0.56. In embodiments of this invention, the type of the liquid bisphenol A type epoxy resin can be YD-128, YD-128A, YD-128M, or YD-128H. In this invention, the epoxy value of the hydrogenated bisphenol A type epoxy resin is preferably 0.44~0.5. In embodiments of this invention, the type of the hydrogenated bisphenol A type epoxy resin can be ST-1000 or ST-3000. In this invention, the epoxy value of the bisphenol F type epoxy resin is preferably 0.55~0.63. In embodiments of this invention, the type of the bisphenol F type epoxy resin can be YDF-162, YDF-165, YDF-170, or YDF-175. This invention utilizes the aforementioned liquid epoxy resin, which exhibits good fluidity. The three-dimensional network structure and the anchoring effect of the liquid epoxy resin bind the network-bound filler (premixed particles) together. Furthermore, because the liquid epoxy resin used in this invention is similar in composition to the resin in decommissioned wind turbine blade particles, it does not introduce other polymer impurities, allowing the wind turbine blade recycled composite material prepared by this invention to be reused after its decommissioning. This invention does not specifically limit the source of the liquid epoxy resin; any commercially available product well-known to those skilled in the art can be used. In the embodiments of this invention, the liquid epoxy resin can be sourced from Guodu Chemical (Kunshan) Co., Ltd.

[0058] In this invention, the epoxy reactive diluent preferably includes one or more of butyl glycidyl ether, phenyl glycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and glycerol triglycidyl ether. The use of an epoxy reactive diluent in this invention facilitates the penetration of liquid epoxy resin into the three-dimensional network structure of the premixed particles.

[0059] In this invention, the curing agent preferably comprises a latent curing agent. In this invention, the latent curing agent can be of type OP-66 or dicyandiamide. Using the above-mentioned curing agent, this invention enables the curing of liquid epoxy resin.

[0060] In this invention, the accelerator is preferably an organic urea accelerator. In an embodiment of this invention, the organic urea accelerator may be UR300.

[0061] In this invention, the mass ratio of the liquid epoxy resin, epoxy reactive diluent, curing agent, and accelerator is 100:(10~30):(3~10):(1~5), preferably 100:(15~25):(5~8):(2~3). By controlling the mass ratio of the liquid epoxy resin, epoxy reactive diluent, curing agent, and accelerator within the above range, this invention allows each component to fully penetrate into the three-dimensional network structure of the premixed particles and undergo curing. The cured resin is then anchored within the three-dimensional network structure of the premixed particles.

[0062] In this invention, the mass ratio of the premixed material with both porous and epoxy group active sites to the liquid epoxy resin is (5~9):(1~5). As one embodiment of this invention, the mass ratio of the premixed material particles to the liquid epoxy resin system can be 5:1, 5:2, 5:3, 5:4:5:5, 6:1, 6:2, 6:3, 6:4, 6:5, 7:1, 7:2, 7:3, 7:4, 7:5, 8:1, 8:2, 8:3, 8:5, 9:1, 9:2, 9:4, or 9:5. By controlling the mass ratio of the premixed material particles to the liquid epoxy resin system within the above range, this invention allows the liquid epoxy resin, epoxy reactive diluent, curing agent, and accelerator to fully penetrate into the three-dimensional network structure of the premixed material particles, and through curing, forms a wind turbine blade recycled composite material with excellent mechanical strength.

[0063] In this invention, the method of mixing the premixed material with both porous and epoxy group active sites with liquid epoxy resin, epoxy reactive diluent, curing agent and accelerator preferably includes: grinding and mixing a portion of the liquid epoxy resin, curing agent and accelerator to obtain abrasive; mixing the abrasive with premixed material particles with both porous and epoxy group active sites, the remaining liquid epoxy resin and epoxy reactive diluent to obtain a mixture.

[0064] In this invention, there is no particular limitation on the amount of liquid epoxy resin used; it can be adjusted as needed. By first mixing a portion of the liquid epoxy resin with the curing agent and accelerator, this invention ensures that the three are mixed evenly, which is more conducive to its full penetration into the three-dimensional network structure when subsequently mixed with a premix that has both porous and epoxy group active sites.

[0065] In this invention, the grinding and mixing apparatus is preferably an automatic three-roll mill. This invention does not impose any special limitations on the grinding and mixing parameters; as long as the three components are mixed evenly, it is sufficient.

[0066] In this invention, the mixing temperature is preferably 60-90°C. As one embodiment of this invention, the mixing temperature can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C. In this invention, the mixing time is preferably 15-20 minutes. As one embodiment of this invention, the mixing time can be 15 minutes, 18 minutes, or 20 minutes. In this invention, the stirring speed is preferably 80-100 r / min. As one embodiment of this invention, the stirring speed can be 80 r / min, 85 r / min, 90 r / min, 95 r / min, or 100 r / min. In this invention, the mixing device is preferably a mixer. This invention, using the above mixing method, can fully penetrate liquid epoxy resin, epoxy reactive diluent, curing agent, and accelerator into the three-dimensional network structure of the premix, which has both porous and epoxy group active sites.

[0067] After obtaining the mixture, the present invention hot-presses the mixture to obtain a wind turbine blade recycled composite material.

[0068] In this invention, the preferred temperature for hot pressing is 140-150°C. As one embodiment of this invention, the hot pressing temperature can be 140°C, 142°C, 145°C, 146°C, 148°C, or 150°C. In this invention, the preferred pressure for hot pressing is 5-10 MPa. As one embodiment of this invention, the pressure for hot pressing can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa. In this invention, the preferred holding time for hot pressing is 20-30 minutes. As one embodiment of this invention, the holding time for hot pressing can be 20 minutes, 25 minutes, or 30 minutes. Under the above hot pressing parameters, this invention enables the liquid epoxy resin component to solidify and anchor itself in the three-dimensional network structure of the premixed particles.

[0069] The method provided by this invention first uses a compound solvent to dissolve the low molecular weight resin and the imperfect three-dimensional network cross-linking structure within the resin in decommissioned wind turbine blade particles, forming a premix with a porous structure and exposed glass fibers. Then, a γ-glycidyl etheroxypropyltrimethoxysilane solution is used to surface-modify the exposed glass fibers in the premix, giving them epoxy group active sites. Subsequently, the premix particles are mixed with liquid epoxy resin, epoxy reactive diluent, curing agent, and accelerator, and then hot-pressed. The active sites in the premix undergo a curing and cross-linking reaction with the liquid epoxy resin system, anchoring the cured epoxy resin within the three-dimensional network structure of the premix particles. The method provided by this invention combines physical dissolution and chemical cross-linking anchoring, is simple to prepare, allows for the recycling of the compound solvent, minimizes environmental pollution, and ensures thorough recycling of the decommissioned wind turbine blade particles, resulting in high economic value.

[0070] The present invention also provides a wind turbine blade regenerated composite material prepared by the preparation method described in the above technical solution.

[0071] In this invention, the regenerated composite material for wind turbine blades has a tensile strength higher than 81.5 MPa, a flexural strength higher than 130.5 MPa, and an impact strength higher than 40.6 J / cm². 2 It has a Tg higher than 119.4℃ and a thermal decomposition temperature higher than 348.3℃, exhibiting excellent mechanical properties and high-temperature resistance.

[0072] The present invention also provides the application of the wind turbine blade recycled composite material described in the above technical solution as a type of engineered wood panel.

[0073] The wind turbine blade recycled composite material prepared by this invention has excellent mechanical properties and thermal stability, so it can be used in artificial boards and applied in a variety of scenarios.

[0074] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0075] The particle size of the decommissioned wind turbine blade particles used in this embodiment of the invention is 1~2mm.

[0076] Based on a total weight of 100 parts of the compound solvent, the components of the compound solvent used in step (1) of this embodiment are: 25 parts of chloroform, 20 parts of benzyl alcohol, 10 parts of acetone, 15 parts of resorcinol, 15 parts of N,N-dimethylformamide and 15 parts of N-methylpyrrolidone.

[0077] Example 1

[0078] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0079] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles with a particle size of 1~2mm;

[0080] (2) After mixing 700g of decommissioned wind turbine blade particles obtained in step (1) with 3500mL of compound solvent, soak them at 25℃ for 8h, then transfer them to an ultrasonic device and perform ultrasonic treatment at an ultrasonic power of 25KHz for 1h. After solid-liquid separation, 595g of premix with porous structure and exposed glass fiber is obtained; the mass of the premix with porous structure and exposed glass fiber accounts for 85% of the mass of decommissioned wind turbine blade particles.

[0081] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in a 1% volume concentration γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution, and the exposed glass fiber in the premix with porous structure and exposed glass fiber is surface modified for 30 min at 25°C. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0082] (4) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 15g of curing agent (dicyandiamide) and 10g of accelerator (UR300) and mix and disperse them evenly to obtain grinding material; then add 500g of premixed particles with both pores and epoxy group active sites, 400g of liquid bisphenol A type resin (YD-128H), 100g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to perform impregnation and filling treatment to obtain mixture;

[0083] (5) Add the mixture obtained in step (4) into the mold and hot press it at 145°C and 10MPa. After 25 minutes, open the mold to obtain the wind turbine blade recycled composite material.

[0084] Example 2

[0085] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0086] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles with a particle size of 1~2mm;

[0087] (2) After mixing 800g of decommissioned wind turbine blade particles obtained in step (1) with 4000mL of compound solvent, soak them at 25°C for 8h, then transfer them to an ultrasonic device and perform ultrasonic treatment at an ultrasonic power of 25KHz for 1h. Then, solid-liquid separation is performed to obtain 680g of premix with porous structure and exposed glass fiber; the mass of the premix with porous structure and exposed glass fiber accounts for 85% of the mass of the decommissioned wind turbine blade particles.

[0088] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in a 1% γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution, and the surface is modified at 25°C for 30 min. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0089] (4) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 12g of curing agent (dicyandiamide) and 8g of accelerator (UR300) and mix and disperse them evenly to obtain grinding material; then add 600g of premixed particles with both pores and epoxy group active sites, 300g of liquid bisphenol A type resin (YD-128H), 80g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture.

[0090] (5) Add the mixture obtained in step (4) into the mold and hot press it at 145°C and 10MPa. After 25 minutes, open the mold to obtain the wind turbine blade recycled composite material.

[0091] Example 3

[0092] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0093] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles with a particle size of 1~2mm;

[0094] (2) After mixing 900g of decommissioned wind turbine blade particles obtained in step (1) with 4500mL of compound solvent, soak them at 25℃ for 8h, then transfer them to an ultrasonic device and perform ultrasonic treatment at an ultrasonic power of 25KHz for 1h. Then, solid-liquid separation is performed to obtain 765g of premix with porous structure and exposed glass fiber; the mass of the premix with porous structure and exposed glass fiber accounts for 85% of the mass of the decommissioned wind turbine blade particles.

[0095] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in a 1% γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution. The exposed glass fiber in the premix with porous structure and exposed glass fiber is surface modified at 25°C for 30 min. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0096] (4) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 9g of curing agent (dicyandiamide) and 6g of accelerator (UR300) and mix and disperse them evenly to obtain a grinding material; then add 700g of premix with both pores and epoxy group active sites, 200g of liquid bisphenol A type resin (YD-128H), 60g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture;

[0097] (5) Add the mixture obtained in step (4) into the mold and hot press it at 145°C and 10MPa. After 25 minutes, open the mold to obtain the wind turbine blade recycled composite material.

[0098] Example 4

[0099] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0100] (1) The retired wind turbine blades are crushed to obtain retired wind turbine blade particles with a particle size of 1~2mm;

[0101] (2) After mixing 1000g of decommissioned wind turbine blade particles obtained in step (1) with 5000mL of compound solvent, soak them at 25℃ for 8h, then transfer them to an ultrasonic device and perform ultrasonic treatment at an ultrasonic power of 25KHz for 1h. Then, solid-liquid separation is performed to obtain 850g of premix with porous structure and exposed glass fiber; the mass of the premix with porous structure and exposed glass fiber accounts for 85% of the mass of the decommissioned wind turbine blade particles.

[0102] (3) The premix with porous structure and exposed glass fiber obtained in step (2) is immersed in a 1% γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution. The exposed glass fiber in the premix with porous structure and exposed glass fiber is surface modified at 25°C for 30 min. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0103] (4) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 6g of curing agent (dicyandiamide) and 4g of accelerator (UR300) and mix and disperse them evenly to obtain grinding material; then add 800g of premixed particles with both pores and epoxy group active sites, 100g of liquid bisphenol A type resin (YD-128H), 40g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture.

[0104] (5) Add the mixture obtained in step (4) into the mold and hot press it at 145°C and 10MPa. After 25 minutes, open the mold to obtain the wind turbine blade recycled composite material.

[0105] Comparative Example 1

[0106] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0107] (1) 100g of liquid bisphenol A type epoxy resin (YD-128H), 9g of curing agent (dicyandiamide) and 6g of accelerator (UR300) were ground and mixed and dispersed evenly to obtain grinding material; then 700g of decommissioned wind turbine blade particles with a particle size of 1~2mm, 200g of liquid bisphenol A type resin (YD-128H), 60g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material were added to a mixer and mixed for 15min at 80℃ and 100r / min to obtain a mixture.

[0108] (2) The mixture obtained in step (1) is added into the mold and hot-pressed at 145°C and 10MPa. After 25 minutes, the mold is opened to obtain the wind turbine blade recycled composite material.

[0109] Comparative Example 2

[0110] A method for preparing an epoxy resin composite material, comprising the following steps:

[0111] (1) Grind 200g of liquid bisphenol A type epoxy resin (YD-128H), 30g of curing agent (dicyandiamide) and 20g of accelerator (UR300) and mix and disperse them evenly to obtain a grinding material; then add 800g of liquid bisphenol A type resin (YD-128H), 200g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and the grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture;

[0112] (2) The mixture obtained in step (1) is added into the mold and hot-pressed at 145°C and 10MPa. After 25 minutes, the mold is opened to obtain the epoxy resin composite material.

[0113] Comparative Example 3

[0114] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0115] (1) 900g of decommissioned wind turbine blade particles with a particle size of 1~2mm were mixed with 2700mL of compound solvent and soaked at 25℃ for 8h. Then, the mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic power of 25KHz for 1h. After solid-liquid separation, 855g of premixed material with porous structure and exposed glass fiber was obtained. The mass of the premixed material with porous structure and exposed glass fiber accounted for 95% of the mass of the decommissioned wind turbine blade particles.

[0116] (2) The premix with porous structure and exposed glass fiber obtained in step (1) is immersed in a 1% γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution. The exposed glass fiber in the premix with porous structure and exposed glass fiber is surface modified at 25°C for 30 min. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0117] (3) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 9g of curing agent (dicyandiamide) and 6g of accelerator (UR300) and mix and disperse them evenly to obtain a grinding material; then add 700g of premix with both pores and epoxy group active sites, 200g of liquid bisphenol A type resin (YD-128H), 60g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture;

[0118] (4) The mixture obtained in step (3) is added into the mold and hot-pressed at 145°C and 10MPa. After 25 minutes, the mold is opened to obtain the wind turbine blade recycled composite material.

[0119] Comparative Example 4

[0120] A method for preparing a recycled composite material for wind turbine blades, comprising the following steps:

[0121] (1) 900g of decommissioned wind turbine blade particles with a particle size of 1~2mm were mixed with 7200mL of compound solvent and soaked at 25℃ for 8h. Then, the mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic power of 25KHz for 1h. After solid-liquid separation, 720g of premixed material with porous structure and exposed glass fiber was obtained. The mass of the premixed material with porous structure and exposed glass fiber accounted for 80% of the mass of the decommissioned wind turbine blade particles.

[0122] (2) The premix with porous structure and exposed glass fiber obtained in step (1) is immersed in a 1% γ-glycidyl etheroxypropyltrimethoxysilane ethanol solution. The exposed glass fiber in the premix with porous structure and exposed glass fiber is surface modified at 25°C for 30 min. Then, solid-liquid separation is performed to obtain a premix with both porous structure and epoxy group active sites.

[0123] (3) Grind 100g of liquid bisphenol A type epoxy resin (YD-128H), 9g of curing agent (dicyandiamide) and 6g of accelerator (UR300) and mix and disperse them evenly to obtain grinding material; then add 700g of premixed particles with both pores and epoxy group active sites, 200g of liquid bisphenol A type resin (YD-128H), 60g of epoxy reactive diluent (1,4-butanediol diglycidyl ether) and grinding material into a mixer and mix for 15min at 80℃ and 100r / min to obtain a mixture.

[0124] (4) The mixture obtained in step (3) is added into the mold and hot-pressed at 145°C and 10MPa. After 25 minutes, the mold is opened to obtain the wind turbine blade recycled composite material.

[0125] Comparative Example 5

[0126] A method for preparing a composite material for wind turbine blades, comprising the following steps:

[0127] (1) 100g of liquid bisphenol A type epoxy resin (YD-128H), 15.3g of curing agent (dicyandiamide) and 10.2g of accelerator (UR300) were ground and mixed and dispersed evenly to obtain a grinding material; then 410g of liquid bisphenol A type resin (YD-128H), 102g of epoxy reactive diluent (1,4-butanediol diglycidyl ether), the grinding material and 490g of chopped glass fiber were added to a mixer and mixed for 15min at 80℃ and 100r / min to obtain a liquid epoxy resin system mixture.

[0128] (2) The liquid epoxy resin system mixture obtained in step (1) is added into the mold and hot-pressed at 145°C and 10MPa. After 25 minutes, the mold is opened to obtain the wind turbine blade composite material.

[0129] Test case

[0130] The mechanical property test results of the composite materials prepared in Examples 1-4 and Comparative Examples 1-5 are shown in Table 1. In Table 1: the test method for tensile strength is GB / T 1040.1-2006, the test method for flexural strength is GB / T 1449-2005, the test method for impact strength is GB / T 1043.2-2018, the test method for Tg (glass transition temperature) is GB / T33061.11-2022, and the test method for thermal decomposition temperature is GB / T 37631-2019.

[0131] Table 1. Mechanical property test results of the composite materials prepared in Examples 1-4 and Comparative Examples 1-5

[0132]

[0133] As can be seen from Table 1, by reasonably controlling the mass ratio of premixed particles, liquid bisphenol A epoxy resin, epoxy reactive diluent, curing agent and accelerator, the wind turbine blade recycled composite material prepared by this invention has significantly improved tensile strength, flexural strength and impact strength compared with the product prepared in the comparative example.

[0134] The comparison between Examples 1-3 and Comparative Example 2 shows that the mechanical properties and thermal stability of the wind turbine blade recycled composite material prepared by the present invention are significantly improved compared with the epoxy resin composite material prepared by Comparative Example 2. The wind turbine blade recycled composite material not only achieves the utilization of 90% or more of the retired wind turbine blade particles, but also reuses glass fiber.

[0135] A comparison of Examples 1-3 and Comparative Examples 1-2 shows that Comparative Example 1, which did not soak the decommissioned wind turbine blade particles in a compound solvent, also showed improved thermodynamic properties compared to the epoxy resin composite material prepared in Comparative Example 2. However, since the decommissioned wind turbine blade particles were not soaked in a compound solvent, there were no three-dimensional network structure pores in the resin system that were conducive to the filling of liquid epoxy resin, and an interpenetrating three-dimensional network cross-linked structure could not be formed, resulting in a slight decrease in the thermodynamic properties of the wind turbine blade regenerated composite material.

[0136] A comparison of Examples 1-3 and Comparative Examples 3-4 shows that in Examples 1-3, the mass ratio of retired wind turbine blade particles to the volume of the compound solvent was 1g:5mL; in Comparative Example 3, the ratio was 1g:3mL; and in Comparative Example 4, the ratio was 1g:8mL. As shown in Table 1, the mass ratio of retired wind turbine blade particles to the volume of the compound solvent affects the mechanical properties of the subsequently prepared composite material. This invention, by rationally adjusting the mass ratio of retired wind turbine blade particles to liquid bisphenol A epoxy resin, achieves the preparation of a recycled composite material with excellent mechanical properties and thermal stability, even with a small proportion of liquid bisphenol A epoxy resin.

[0137] As can be seen from the comparison between Example 3 and Comparative Example 5, under the same glass fiber content, the thermodynamic properties of the wind turbine blade recycled composite material prepared by combining wind turbine blade recycled materials with a liquid epoxy resin system are only slightly reduced compared with the new composite material prepared by a pure liquid epoxy resin system. The performance parameters of the recycled composite material reach 85% or more of those of the new composite material, which will not lead to downgrading and can meet the application needs of different scenarios.

[0138] The results above demonstrate that the method provided by this invention achieves efficient and value-added recycling of decommissioned wind turbine blades, avoiding the separation process between glass fiber and resin while preserving the mechanical strength of the glass fiber, thus saving resources and possessing significant economic and application value. Furthermore, because this invention utilizes a liquid epoxy resin system to impregnate and fill a premixed material containing both pores and epoxy group active sites, no new impurities are introduced. This allows the wind turbine blade recycled composite material prepared using this method to be recycled again after use, greatly reducing solid waste generation and lowering the production cost of wind turbine blade recycled composite materials.

[0139] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a recycled composite material for wind turbine blades, characterized in that, Includes the following steps: (1) The decommissioned wind turbine blade particles are mixed with a compound solvent and then soaked to obtain premixed particles; the mass of the premixed particles accounts for 80-95% of the mass of the decommissioned wind turbine blade particles; (2) The premixed particles obtained in step (1) are mixed with liquid epoxy resin, epoxy diluent, curing agent and accelerator to obtain a mixture; The mass ratio of the premixed granules to the liquid epoxy resin is 5~9:1~5; The mass ratio of the liquid epoxy resin, epoxy diluent, curing agent, and accelerator is 100:10~30:3~10:1~5; (3) The mixture obtained in step (2) is hot-pressed to obtain a wind turbine blade recycled composite material; The particle size of the decommissioned wind turbine blade particles in step (1) is 0.2~2mm; By weight, the components of the compound solvent in step (1) include: 20-50 parts of dichloromethane, 30-40 parts of benzyl alcohol, 10-30 parts of methanol, 1-10 parts of phenol, 1-10 parts of N,N-dimethylformamide and 1-10 parts of N-methylpyrrolidone.

2. The preparation method according to claim 1, characterized in that, In step (1), the ratio of the mass of the decommissioned wind turbine blade particles to the volume of the compound solvent is 1g:3~8mL.

3. The preparation method according to claim 1, characterized in that, The soaking treatment in step (1) is performed under ultrasound; the soaking temperature is room temperature; and the soaking time is 1-2 hours.

4. The preparation method according to claim 1, characterized in that, The liquid epoxy resin in step (2) includes one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and bisphenol F type epoxy resin.

5. The preparation method according to claim 1, characterized in that, The epoxy diluent in step (2) includes one or more of butyl glycidyl ether, phenyl glycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether and glycerol triglycidyl ether.

6. The preparation method according to claim 1, characterized in that, In step (3), the hot pressing temperature is 140~150℃; the hot pressing pressure is 5~10MPa; and the hot pressing holding time is 20~30min.

7. The wind turbine blade recycled composite material prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the wind turbine blade recycled composite material of claim 7 as a type of engineered wood panel.

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