Glass fiber cloth for wind power blade as well as preparation method and application of glass fiber cloth

Abstract

The invention discloses glass fiber cloth for a wind power blade and a preparation method and application thereof, and belongs to the field of glass fiber cloth. The glass fiber cloth for the wind power blade comprises glass fiber base cloth and a corrosion-resistant coating, wherein the surface of the glass fiber base cloth is coated with the corrosion-resistant coating; the glass fiber base cloth comprises an upper layer, a middle layer and a lower layer; the upper layer is made of first glass fibers laid at the angle of-45 degrees, the lower layer is made of second glass fibers laid at the angle of 45 degrees, the middle layer is made of modified fibers laid at the angle of 90 degrees, and the intersections of the first glass fibers, the second glass fibers and the modified fibers are woven and fixed by polyester yarns; wherein the modified fiber is third glass fiber wrapped by polypropylene fiber; in the modified fiber, the volume ratio of the polypropylene fiber to the third glass fiber is (45-48): (52-55). The glass fiber cloth has excellent mechanical properties and wear resistance and corrosion resistance, and can further improve the wind area adaptability and prolong the service life of the wind power blade.

Description

Technical Field

[0001] This invention belongs to the field of glass fiber cloth, specifically relating to a glass fiber cloth for wind turbine blades, its preparation method, and its application. Background Technology

[0002] Fiberglass cloth is a mesh-like reinforcing material made by drawing molten glass into fibers and then weaving them. Its core components are silicon dioxide and other metal oxides, and surface impregnation with a wetting agent enhances its bonding strength with resin. As a key reinforcing skeleton in composite materials, fiberglass cloth is known for its lightweight and high strength: its density is only 2.54 g / cm³ (about 1 / 4 that of steel), while its tensile strength is as high as 3100 MPa (more than 3 times that of steel). It also possesses excellent corrosion resistance, insulation, and dimensional stability, and is widely used in thermal insulation, heat resistance, fireproofing, new energy, and occupational safety protection.

[0003] The blade is the most fundamental and critical component of a wind turbine. Its good design, reliable quality, and superior performance are decisive factors in ensuring the normal and stable operation of the unit. Fiberglass cloth is one of the main materials used in the structural design of wind turbine blades, and its strength and hardness have a significant impact on the blade's weight, strength, fatigue performance, and lifespan.

[0004] Currently, for onshore wind turbine blades, taking 3MW units as an example, the industry mainly uses fabrics such as E-UD1200 / M50 and E-UD1250, whose strength, modulus, and corrosion resistance do not meet the requirements of offshore wind power. Therefore, in the fiberglass cloth production stage, how to improve blade performance and enhance the blade's ability to withstand harsh environments has become a key focus for the entire industry.

[0005] Patent application CN113818120A discloses a method for preparing a high-modulus uniaxial glass fiber fabric. By reducing the fabric's basis weight in the 90° direction and increasing its basis weight in the 0° direction, the performance of the glass fiber fabric is improved. Furthermore, by adjusting the arrangement and density of the weft yarns in the second yarn layer, the glass fiber fabric achieves good structural stability. However, this patent only improves the modulus of the glass fiber fabric through structural design and fabric arrangement adjustments, without improving the material properties of the glass fiber fabric itself. Therefore, the improvement in the material's mechanical properties is limited, and the material's ability to withstand harsh environments needs further improvement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a glass fiber cloth for wind turbine blades, its preparation method and application. The glass fiber cloth has excellent mechanical properties and wear and corrosion resistance, which can further improve the wind zone adaptability and service life of wind turbine blades.

[0007] To achieve the above objectives, according to one aspect of the present invention, a fiberglass cloth for wind turbine blades is provided, comprising a fiberglass base cloth and a corrosion-resistant coating applied to the surface of the fiberglass base cloth; the fiberglass base cloth comprises an upper layer, a middle layer, and a lower layer; the upper layer consists of first fiberglass laid at -45°, the lower layer consists of second fiberglass laid at 45°, and the middle layer consists of modified fiber laid at 90°; the intersections of the first fiberglass, the second fiberglass, and the modified fiber are woven and fixed with polyester filaments; wherein the modified fiber is a third fiberglass wrapped with polypropylene fiber; and the volume ratio of the polypropylene fiber to the third fiberglass in the modified fiber is 45-48:52-55.

[0008] The inventors discovered that by using polypropylene fibers wrapped around a third glass fiber as described in this invention as the intermediate layer, and further controlling the volume ratio of polypropylene fibers to the third glass fiber in the modified fiber, the polypropylene fibers can fully protect the glass fiber, overcoming the performance defects of single fibers and exerting a synergistic effect. In this case, the glass fiber cloth exhibits excellent mechanical properties. If the volume content of glass fiber in the modified fiber is too high, the polypropylene fibers cannot completely cover the glass fiber, leading to a decrease in the cohesion between the glass fibers, thus reducing the breaking strength. Conversely, if the volume content of glass fiber in the modified fiber is too low, the breaking strength will also decrease accordingly.

[0009] In this invention, the diameters of the first and second glass fibers are both 13-15 μm. It is understood that their diameters can be any specific value among 13 μm, 14 μm, and 15 μm, or any value within the range of 13-15 μm. The diameter of the third glass fiber is 17-20 μm. It is understood that its diameter can be any specific value among 17 μm, 18 μm, 19 μm, and 20 μm, or any value within the range of 17-20 μm. In this invention, the fineness of the polypropylene fiber is 100-120 tex.

[0010] In this invention, the thickness of the upper and lower layers is 0.2-0.4 mm. It can be understood that the thickness can be any specific value among 0.2 mm, 0.3 mm, and 0.4 mm, or any value within the range of 0.2-0.4 mm. The thickness of the intermediate layer is 0.5-0.7 mm. It can be understood that the thickness can be any specific value among 0.5 mm, 0.6 mm, and 0.7 mm, or any value within the range of 0.5-0.7 mm.

[0011] In this invention, the unit area mass of the upper and lower layers is 800±45g / m². 2 The mass per unit area of ​​the intermediate layer is 700±45 g / m². 2 .

[0012] In this invention, the intersections of the first glass fiber, the second glass fiber, and the modified fiber are secured with polyester filaments using a warp-faced braiding method. The inventors discovered that the stability of the glass fiber cloth improves as the polyester filament density and stitch length decrease. Therefore, this invention uses 75-100D low-elasticity polyester filaments with a stitch length of 3-5 mm and a braiding density of 5-7 ends / inch. The glass fiber cloth bound with the polyester filaments used in this invention exhibits better stability, is less prone to unraveling, and is more suitable for industrial applications.

[0013] In this invention, the raw materials for the corrosion-resistant coating include, by weight percentage, 9-14 wt% epoxy reactive diluent, 0.5-1 wt% polydimethylsiloxane, and 0.5-1 wt% composite filler, with the balance being epoxy resin and polyamide curing agent in a mass ratio of 1:1; wherein, the composite filler is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a mass ratio of 1-1.5:1.

[0014] Preferably, in the raw materials of the corrosion-resistant coating, the epoxy reactive diluent accounts for 9-14 wt% by weight. It is understood that the weight percentage can be any specific value among 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, and 14 wt%, or any value within the range of 9-14 wt%. More preferably, the epoxy reactive diluent is butyl glycidyl ether.

[0015] Preferably, in the raw materials of the corrosion-resistant coating, the weight percentage of polydimethylsiloxane is 0.5-1 wt%. It can be understood that the weight percentage can be any specific value among 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, and 1 wt%, or any value within the range of 0.5-1 wt%.

[0016] Preferably, in the raw materials of the corrosion-resistant coating, the composite filler accounts for 0.5-1 wt% by weight. This can be understood as any specific value among 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, and 1 wt%, or any value within the range of 0.5-1 wt%. More preferably, the composite filler is a composite of silane coupling agent-modified fly ash microspheres and graphene oxide in a mass ratio of 1-1.5:1. This can be understood as any specific value among 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, and 1.5:1, or any value within the range of 1-1.5:1. In this invention, the fly ash microspheres have a particle size of 2-10 μm, and the graphene oxide has a thickness of 3.4-7.0 nm. Using fly ash microspheres with the particle size described in this invention results in more uniform dispersion, thereby ensuring the uniformity of material properties. The inventors have discovered that adding the composite filler of the above-mentioned content to the corrosion-resistant coating system described in this invention can effectively block the penetration of corrosive media, thereby effectively improving the wear resistance, corrosion resistance and mechanical properties of the coating.

[0017] Preferably, the raw materials for the corrosion-resistant coating, by weight percentage, consist of epoxy resin and polyamide curing agent in a 1:1 mass ratio. More preferably, the polyamide curing agent is polyamide 650, and the epoxy resin is bisphenol A type epoxy resin with an epoxy value of 0.48-0.54 eq / 100g.

[0018] In this invention, the preparation method of the composite filler includes: mixing the fly ash microspheres with an ethanol solution of a silane coupling agent, stirring and reacting at 100-110°C for 1.5-2 hours, and drying to obtain the silane coupling agent-modified fly ash microspheres; dispersing the silane coupling agent-modified fly ash microspheres and graphene oxide in a DMF solution, stirring at 90-100°C for 1-1.5 hours, and drying to obtain the composite filler. Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane. This invention utilizes silane coupling agent modification to coat the surface of the fly ash microspheres with oxygen-containing functional groups, thereby enhancing their dispersion compatibility in the system.

[0019] The inventors discovered that dispersed graphene oxide reacts chemically with the oxygen-containing functional groups on the surface of modified fly ash microspheres to form a composite filler with a three-dimensional structure. On one hand, the fly ash microspheres attached to the surface increase the interlayer spacing of the graphene oxide, reduce the interaction energy between graphene oxide sheets, and improve the fluidity of the filler in the system. Moreover, the dispersion fluidity of fly ash microspheres in the system is higher than that of graphene, driving the dispersion of graphene oxide and further improving the dispersibility of graphene oxide in the system. On the other hand, the improved composite filler enhances the density of the coating, thereby improving the wear resistance and corrosion resistance of the coating. The inventors further discovered that the mass ratio of silane coupling agent-modified fly ash microspheres to graphene oxide needs to be strictly controlled. If the content of graphene oxide is too high or too low, the corrosion resistance of the coating will decrease. This is because if the content of graphene oxide is too high, it is easy for it to agglomerate inside the coating. Agglomeration will create new defects, increasing the possibility of corrosive media penetration, thereby reducing the corrosion resistance of the coating. If the content of graphene oxide is too low, the density of the coating will decrease, which will also reduce the corrosion resistance of the coating.

[0020] According to another aspect of the present invention, a method for preparing a glass fiber cloth for wind turbine blades as described in any of the above claims is also provided, the method comprising the following steps: (1) Preparation of modified fiber: The polypropylene fiber and the third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is mounted on a spindle and rotated and wrapped. The third glass fiber is directly fed in and the modified fiber is braided. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain the glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 120-130℃ for 1-2 hours to obtain the glass fiber cloth for wind turbine blades.

[0021] In this invention, in step (1), the modified fiber is prepared by adding the polypropylene fiber and the third glass fiber into a high-speed braiding machine in proportion, the polypropylene fiber is mounted on the spindle and rotated and wrapped, and the third glass fiber is directly fed in to weave the modified fiber.

[0022] In this invention, in step (2), the glass fiber base fabric is prepared by sequentially laying the first glass fiber, the modified fiber, and the second glass fiber in weft layers at -45°, 90°, and 45°, and then weaving and fixing them with polyester yarn to obtain the glass fiber base fabric.

[0023] In this invention, in step (3), the raw materials of the corrosion-resistant coating are mixed in proportion and then immersed in the glass fiber base cloth obtained in step (2). The glass fiber base cloth is then taken out and cured at 120-130℃ for 1-2 hours to obtain the glass fiber cloth for wind turbine blades.

[0024] According to another aspect of the present invention, the application of the above-described glass fiber cloth or the glass fiber cloth prepared according to the above method in wind turbine blades is also provided.

[0025] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention creatively designs a glass fiber cloth for wind turbine blades. The middle layer uses a third glass fiber wrapped with polypropylene fiber as described in the present invention, and further controls the volume ratio of polypropylene fiber and third glass fiber in the modified fiber so that the polypropylene fiber can fully protect the glass fiber, overcome the performance defects of single fiber, exert a synergistic effect, and make the glass fiber cloth have excellent mechanical properties.

[0026] (2) This invention also improves the corrosion resistance and mechanical properties of the coating by adding a certain mass ratio of silane coupling agent to modify the fly ash microspheres and graphene oxide composite. On the one hand, the fly ash microspheres attached to the surface increase the interlayer spacing of graphene oxide, reduce the interaction energy between graphene oxide sheets, improve the fluidity of the filler in the system, and the dispersion fluidity of fly ash microspheres in the system is higher than that of graphene oxide, thereby promoting the dispersion of graphene oxide and further improving the dispersion of graphene oxide in the system. On the other hand, the composite filler improves the density of the coating, thereby improving the wear resistance and corrosion resistance of the coating.

[0027] (3) The preparation method of the glass fiber cloth for wind turbine blades provided by the present invention is simple and suitable for industrial production. Attached Figure Description

[0028] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the glass fiber cloth base fabric for wind turbine blades according to an embodiment of the present invention.

[0030] Figure 1 In the middle, 01 is the upper layer; 02 is the middle layer; 03 is the lower layer; 04 is the polyester filament. Detailed Implementation

[0031] This invention provides a fiberglass cloth for wind turbine blades, comprising a fiberglass base cloth and a corrosion-resistant coating applied to the surface of the fiberglass base cloth; the fiberglass base cloth comprises an upper layer, a middle layer, and a lower layer; the upper layer consists of first fiberglass laid at -45°, the lower layer consists of second fiberglass laid at 45°, and the middle layer consists of modified fiber laid at 90°; the intersections of the first fiberglass, second fiberglass, and modified fiber are woven and fixed with polyester filaments; wherein, the modified fiber is a third fiberglass wrapped with polypropylene fiber; in the modified fiber, the volume ratio of polypropylene fiber to the third fiberglass is 45-48:52-55.

[0032] In some embodiments, the raw materials for the corrosion-resistant coating include, by weight percentage, 9-14 wt% epoxy reactive diluent, 0.5-1 wt% polydimethylsiloxane, and 0.5-1 wt% composite filler, with the balance being epoxy resin and polyamide curing agent in a mass ratio of 1:1; wherein the composite filler is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a mass ratio of 1-1.5:1.

[0033] In some embodiments, the diameters of the first and second glass fibers are both 13-15 μm, and the diameter of the third glass fiber is 17-20 μm.

[0034] In some embodiments, the thickness of the upper and lower layers is 0.2-0.4 mm, and the thickness of the middle layer is 0.5-0.7 mm.

[0035] In some embodiments, the polypropylene fiber fineness is 100-120 tex.

[0036] In some embodiments, the intersections of the first glass fiber, the second glass fiber, and the modified fiber are woven and fixed with polyester filaments using a warp-flat weave.

[0037] In some embodiments, the fly ash microspheres have a particle size of 2-10 μm and the graphene oxide has a thickness of 3.4-7.0 nm.

[0038] In some embodiments, the preparation method of the composite filler includes: mixing fly ash microspheres with an ethanol solution of silane coupling agent, stirring and reacting at 100-110°C for 1.5-2 hours, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing silane coupling agent modified fly ash microspheres and graphene oxide in DMF solution, stirring at 90-100°C for 1-1.5 hours, and drying to obtain the composite filler.

[0039] The present invention also provides a method for preparing a glass fiber cloth for wind turbine blades according to any of the above claims, the method comprising the following steps: (1) Preparation of modified fiber: Polypropylene fiber and third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is installed on the spindle and rotated and wrapped, while the third glass fiber is directly fed in to braid the modified fiber. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 120-130℃ for 1-2 hours to obtain the glass fiber cloth for wind turbine blades.

[0040] The present invention also provides an application of the above-described glass fiber cloth or the glass fiber cloth prepared according to the above method in wind turbine blades.

[0041] The present invention will be described in detail below through embodiments, wherein Embodiment 1 is the preferred embodiment. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0042] The chemical additives used in the embodiments and comparative examples of this invention are all commercially available, and the specific information is as follows: First and second glass fibers: HCR9029-300, both with a diameter of 14μm, purchased from Jiangsu Jiuding New Material Co., Ltd.; third glass fiber: HCR9029-1200, with a diameter of 17μm, purchased from Jiangsu Jiuding New Material Co., Ltd.; polyester filament: 75-100D low-elastic polyester filament, purchased from Zhejiang Zhongdi Fiber Technology Co., Ltd.; polypropylene fiber: fineness 100-120tex, purchased from Shaoxing Qianzhan Chemical Fiber Co., Ltd.

[0043] Fly ash microspheres: particle size 3-5μm, purchased from Shandong Wenqu New Material Technology Co., Ltd.; Graphene oxide: thickness 3.4-7.0nm, purchased from Suzhou Carbon-Feng Graphene Technology Co., Ltd.; Silane coupling agent: γ-aminopropyltriethoxysilane, purchased from Aladdin Reagent Co., Ltd.; DMF, ethanol: purchased from Aladdin Reagent Co., Ltd.; Epoxy reactive diluent: 660A, purchased from Wuxi Xihua Chemical Technology Co., Ltd.; Polydimethylsiloxane: PDMS, purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd.; Epoxy resin: Bisphenol A type E-51, epoxy value 0.48-0.54eq / 100g, purchased from Jinan Baorui Resin Chemical Co., Ltd.; Polyamide curing agent: Polyamide 650, purchased from Jinan Baorui Resin Chemical Co., Ltd.

[0044] Reference Figure 1A fiberglass cloth base fabric for wind turbine blades includes an upper layer 01, a middle layer 02, and a lower layer 03; the upper layer 01 is a first fiberglass laid at -45°, the lower layer 03 is a second fiberglass laid at 45°, the middle layer 02 is a modified fiber laid at 90°, and the intersections of the first fiberglass, the second fiberglass, and the modified fiber are woven and fixed with polyester filaments 04 using a warp-flat weaving method.

[0045] Preparation Example 1 This preparation example prepares a composite filler. The preparation method of the composite filler includes: mixing 1g of fly ash microspheres with 100g of ethanol solution containing 1.5wt% silane coupling agent, stirring at 110℃ for 1.5h, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing 1.3g of silane coupling agent modified fly ash microspheres and 1g of graphene oxide in DMF solution, stirring at 100℃ for 1h, and drying to obtain composite filler A.

[0046] Preparation Example 2 This preparation example prepares a composite filler. The preparation method of the composite filler includes: mixing 1g of fly ash microspheres with 100g of ethanol solution containing 1.5wt% silane coupling agent, stirring at 100℃ for 2h, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing 1g of silane coupling agent modified fly ash microspheres and 1g of graphene oxide in DMF solution, stirring at 90℃ for 1.5h, and drying to obtain composite filler B.

[0047] Preparation Example 3 This preparation example prepares a composite filler. The preparation method of the composite filler includes: mixing 1g of fly ash microspheres with 100g of ethanol solution containing 1.5wt% silane coupling agent, stirring at 100℃ for 2h, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing 1.5g of silane coupling agent modified fly ash microspheres and 1g of graphene oxide in DMF solution, stirring at 90℃ for 1.5h, and drying to obtain composite filler C.

[0048] Preparation Example 4 This preparation example prepares a composite filler. The preparation method of the composite filler includes: mixing 1g of fly ash microspheres with 100g of ethanol solution containing 1.5wt% silane coupling agent, stirring at 110℃ for 1.5h, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing 0.5g of silane coupling agent modified fly ash microspheres and 1g of graphene oxide in DMF solution, stirring at 100℃ for 1h, and drying to obtain composite filler D.

[0049] Preparation Example 5 This preparation example prepares a composite filler. The preparation method of the composite filler includes: mixing 1g of fly ash microspheres with 100g of ethanol solution containing 1.5wt% silane coupling agent, stirring at 110℃ for 1.5h, and drying to obtain silane coupling agent modified fly ash microspheres; dispersing 1.8g of silane coupling agent modified fly ash microspheres and 1g of graphene oxide in DMF solution, stirring at 100℃ for 1h, and drying to obtain composite filler E.

[0050] Example 1 This embodiment of a fiberglass cloth for wind turbine blades includes a fiberglass base cloth and a corrosion-resistant coating applied to the surface of the fiberglass base cloth. The fiberglass base cloth includes an upper layer, a middle layer, and a lower layer. The upper layer consists of first fiberglass laid at -45°, the lower layer consists of second fiberglass laid at 45°, and the middle layer consists of modified fiber laid at 90°. The intersections of the first, second, and modified fibers are woven and fixed with polyester filaments using a warp-plain weave. The modified fiber is a third fiberglass wrapped with polypropylene fiber. The volume ratio of polypropylene fiber to the third fiberglass in the modified fiber is 46:54. The raw materials for the corrosion coating include, by weight percentage: 12 wt% epoxy reactive diluent, 0.8 wt% polydimethylsiloxane, and 0.8 wt% composite filler A, with the balance being epoxy resin and polyamide curing agent in a 1:1 mass ratio; wherein, composite filler A is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a 1.3:1 mass ratio; the thickness of the upper and lower layers is 0.3 mm, and the thickness of the middle layer is 0.6 mm; the needle length of the polyester filament is 4 mm, and the weaving density of the polyester filament is 6 ends / inch; the unit area mass of the upper layer is 780 g / m². 2 The mass per unit area of ​​the lower layer is 780 g / m². 2 The mass per unit area of ​​the intermediate layer is 700 g / m². 2 .

[0051] A method for preparing fiberglass cloth for wind turbine blades includes the following steps: (1) Preparation of modified fiber: Polypropylene fiber and third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is installed on the spindle and rotated and wrapped, while the third glass fiber is directly fed in to braid the modified fiber. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 125°C for 1.5h to obtain the glass fiber cloth for wind turbine blades.

[0052] Example 2 This embodiment of a fiberglass cloth for wind turbine blades includes a fiberglass base cloth and a corrosion-resistant coating applied to the surface of the fiberglass base cloth. The fiberglass base cloth includes an upper layer, a middle layer, and a lower layer. The upper layer consists of first fiberglass laid at -45°, the lower layer consists of second fiberglass laid at 45°, and the middle layer consists of modified fiber laid at 90°. The intersections of the first, second, and modified fibers are woven and fixed with polyester filaments using a warp-flat weave. The modified fiber is a third fiberglass wrapped with polypropylene fiber. The volume ratio of polypropylene fiber to the third fiberglass in the modified fiber is 45:55. The raw materials for the corrosion-resistant coating include, by weight percentage: 9 wt% epoxy reactive diluent, 0.5 wt% polydimethylsiloxane, and 0.5 wt% composite filler B, with the balance being epoxy resin and polyamide curing agent in a 1:1 mass ratio; wherein, composite filler B is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a 1:1 mass ratio; the thickness of the upper and lower layers is 0.2 mm, and the thickness of the middle layer is 0.5 mm; the needle length of the polyester filament is 5 mm, and the weaving density of the polyester filament is 5 ends / inch; the unit area mass of the upper layer is 800 g / m². 2 The mass per unit area of ​​the lower layer is 800 g / m². 2 The mass per unit area of ​​the intermediate layer is 720 g / m². 2 .

[0053] A method for preparing fiberglass cloth for wind turbine blades includes the following steps: (1) Preparation of modified fiber: Polypropylene fiber and third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is installed on the spindle and rotated and wrapped, while the third glass fiber is directly fed in to braid the modified fiber. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 120°C for 2 hours to obtain the glass fiber cloth for wind turbine blades.

[0054] Example 3 This embodiment of a fiberglass cloth for wind turbine blades includes a fiberglass base cloth and a corrosion-resistant coating applied to the surface of the fiberglass base cloth. The fiberglass base cloth includes an upper layer, a middle layer, and a lower layer. The upper layer consists of first fiberglass laid at -45°, the lower layer consists of second fiberglass laid at 45°, and the middle layer consists of modified fiber laid at 90°. The intersections of the first, second, and modified fibers are woven and fixed with polyester filaments using a warp-flat weave. The modified fiber is a third fiberglass wrapped with polypropylene fiber. The volume ratio of polypropylene fiber to the third fiberglass in the modified fiber is 48:52. The raw materials for the corrosion-resistant coating include, by weight percentage: 14 wt% epoxy reactive diluent, 1 wt% polydimethylsiloxane, and 1 wt% composite filler C, with the balance being epoxy resin and polyamide curing agent in a 1:1 mass ratio; wherein, composite filler C is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a 1.5:1 mass ratio; the thickness of the upper and lower layers is 0.4 mm, and the thickness of the middle layer is 0.7 mm; the needle length of the polyester filament is 3 mm, and the weaving density of the polyester filament is 7 ends / inch; the unit area mass of the upper layer is 820 g / m². 2 The mass per unit area of ​​the lower layer is 820 g / m². 2 The mass per unit area of ​​the intermediate layer is 685 g / m³. 2 .

[0055] A method for preparing fiberglass cloth for wind turbine blades includes the following steps: (1) Preparation of modified fiber: Polypropylene fiber and third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is installed on the spindle and rotated and wrapped, while the third glass fiber is directly fed in to braid the modified fiber. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 130°C for 1 hour to obtain the glass fiber cloth for wind turbine blades.

[0056] Comparative Example 1 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that the volume ratio of polypropylene fiber to third glass fiber in the modified fiber is 40:60.

[0057] Comparative Example 2 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that the volume ratio of polypropylene fiber to third glass fiber in the modified fiber is 55:45.

[0058] Comparative Example 3 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that an equal amount of composite filler D is used to replace composite filler A in the corrosion-resistant coating.

[0059] Comparative Example 4 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that an equal amount of composite filler E is used to replace composite filler A in the corrosion-resistant coating.

[0060] Comparative Example 5 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that the middle layer is a third glass fiber laid at 90°.

[0061] Comparative Example 6 The preparation method of the glass fiber cloth in this comparative example is exactly the same as that in Example 1, except that the third glass fiber is replaced with an equal amount of HCR9029-1200 using HCR9029-300.

[0062] Performance testing The 500m finished glass fiber cloths prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to performance tests according to the following testing methods.

[0063] Abrasion resistance: The abrasion resistance of the glass fiber cloth was tested using an LFY-109B fiber abrasion tester. 240-grit sandpaper was fixed to the friction shaft of the instrument. Several sample sections were taken, with one end suspended by a 100g weight, and the other end fixed to the instrument. The instrument was started, and the glass fiber continuously rubbed against the friction shaft until it broke. The number of friction cycles at which the fiber broke was recorded. Ten tests were performed on each sample group, and the average value was calculated.

[0064] Fracture strength: Tested in accordance with GB / T7689.5-2013.

[0065] Corrosion resistance: The samples were treated with alkali or acid solutions respectively, and the mechanical properties of the fiber cloth after alkali or acid treatment were tested, and the strength loss rate was calculated.

[0066] Alkali treatment: Place the sample in a 5% sodium hydroxide solution, ensuring that the solution level submerges the sample by at least 25 mm. Maintain a constant temperature of 50°C for 7 days, then remove and dry.

[0067] Acid treatment: Place the sample in a 10% hydrochloric acid solution, ensuring that the solution level submerges the sample by at least 25 mm. Maintain a constant temperature of 50°C for 7 days, then remove and dry.

[0068] The formula for calculating the strength loss rate is: Strength loss rate = (Tear strength of untreated fiber cloth - Tear strength of fiber cloth treated with alkali / acid) / Tear strength of untreated fiber cloth × 100%.

[0069] Table 1. Performance of glass fiber cloth in Examples 1-3 and Comparative Examples 1-6 .

[0070] As shown in Table 1, the glass fiber cloths prepared in Examples 1-3 all exhibited abrasion resistance exceeding 4000 cycles, radial and weft tensile strengths exceeding 8800 N, and low strength loss rates after acid or alkali treatment. This indicates that the glass fiber cloths in Examples 1-3 possess both excellent mechanical properties and abrasion and corrosion resistance. A comparison between Example 1 and Comparative Example 1 reveals that the volume content of glass fiber in the modified fiber in Comparative Example 1 is relatively high. Because the polypropylene fiber cannot completely coat the glass fiber, the cohesion between the glass fibers is reduced, resulting in lower tensile strength. A comparison between Example 1 and Comparative Example 2 shows that the volume content of glass fiber in the modified fiber in Comparative Example 2 is relatively low, and the tensile strength is correspondingly lower. A comparison between Example 1 and Comparative Examples 3 and 4 shows that the graphene oxide content in the composite filler in Comparative Examples 3 and 4 is either too high or too low, and the strength loss rates after acid or alkali treatment are significantly increased, indicating reduced corrosion resistance of the coating. A comparison between Example 1 and Comparative Example 5 shows that in Comparative Example 5, the use of unmodified third glass fiber in the intermediate layer significantly reduces the tensile strength of the glass fiber cloth. A comparison between Example 1 and Comparative Example 6 shows that in Comparative Example 6, the different diameters of the third glass fiber also result in a significant reduction in the tensile strength of the glass fiber cloth.

[0071] Therefore, this invention creatively designs a glass fiber cloth for wind turbine blades, with a third glass fiber wrapped with polypropylene fibers of this invention in the middle layer. Furthermore, by controlling the volume ratio of polypropylene fibers to the third glass fiber in the modified fiber, the polypropylene fibers can fully protect the glass fibers, overcoming the performance defects of single fibers and achieving a synergistic effect, resulting in excellent mechanical properties of the glass fiber cloth. This invention further enhances the corrosion resistance and mechanical properties of the coating by adding a certain mass ratio of silane coupling agent to modify fly ash microspheres and graphene oxide composites in the corrosion-resistant coating, effectively blocking the penetration of corrosive media.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A type of fiberglass cloth for wind turbine blades, characterized in that, The product comprises a glass fiber base fabric and a corrosion-resistant coating applied to the surface of the glass fiber base fabric. The glass fiber base fabric includes an upper layer, a middle layer, and a lower layer. The upper layer consists of first glass fibers laid at -45°, the lower layer consists of second glass fibers laid at 45°, and the middle layer consists of modified fibers laid at 90°. The intersections of the first glass fibers, second glass fibers, and modified fibers are woven and fixed with polyester filaments. The modified fibers are third glass fibers wrapped with polypropylene fibers. The volume ratio of the polypropylene fibers to the third glass fibers in the modified fibers is 45-48:52-55.

2. The fiberglass cloth for wind turbine blades according to claim 1, characterized in that, The raw materials of the corrosion-resistant coating include, by weight percentage, 9-14 wt% epoxy reactive diluent, 0.5-1 wt% polydimethylsiloxane, and 0.5-1 wt% composite filler, with the balance being epoxy resin and polyamide curing agent in a mass ratio of 1:1; wherein, the composite filler is a composite of silane coupling agent modified fly ash microspheres and graphene oxide in a mass ratio of 1-1.5:

1.

3. The fiberglass cloth for wind turbine blades according to claim 1, characterized in that, The diameters of the first and second glass fibers are both 13-15 μm, and the diameter of the third glass fiber is 17-20 μm.

4. The fiberglass cloth for wind turbine blades according to claim 1, characterized in that, The thickness of the upper and lower layers is 0.2-0.4 mm, and the thickness of the middle layer is 0.5-0.7 mm.

5. The fiberglass cloth for wind turbine blades according to claim 1, characterized in that, The polypropylene fiber has a fineness of 100-120 tex.

6. The fiberglass cloth for wind turbine blades according to claim 1, characterized in that, The first glass fiber, the second glass fiber, and the modified fiber are intersected and fixed with polyester yarn using a warp-flat weaving method.

7. The fiberglass cloth for wind turbine blades according to claim 2, characterized in that, The fly ash microspheres have a particle size of 2-10 μm, and the graphene oxide has a thickness of 3.4-7.0 nm.

8. The fiberglass cloth for wind turbine blades according to claim 2, characterized in that, The preparation method of the composite filler includes: mixing the fly ash microspheres with an ethanol solution of a silane coupling agent, stirring and reacting at 100-110℃ for 1.5-2 hours, and drying to obtain the silane coupling agent modified fly ash microspheres; dispersing the silane coupling agent modified fly ash microspheres and graphene oxide in a DMF solution, stirring at 90-100℃ for 1-1.5 hours, and drying to obtain the composite filler.

9. A method for preparing glass fiber cloth for wind turbine blades according to any one of claims 1-8, characterized in that, The method includes the following steps: (1) Preparation of modified fiber: The polypropylene fiber and the third glass fiber are added to a high-speed braiding machine in proportion. The polypropylene fiber is mounted on a spindle and rotated and wrapped. The third glass fiber is directly fed in and the modified fiber is braided. (2) Preparation of glass fiber base fabric: The first glass fiber, modified fiber and second glass fiber are laid in the weft layers at -45°, 90° and 45° in sequence, and polyester yarn is used for weaving and fixing to obtain the glass fiber base fabric; (3) After mixing the raw materials of the corrosion-resistant coating in proportion, immerse them in the glass fiber base cloth obtained in step (2), take out the glass fiber base cloth, and cure it at 120-130℃ for 1-2 hours to obtain the glass fiber cloth for wind turbine blades.

10. The application of the glass fiber cloth according to any one of claims 1-8 or the glass fiber cloth prepared according to the method of claim 9, characterized in that: Application in the manufacture of wind turbine blades.

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