Preparation method of low-modulus high-adhesion wind power UD block using glass fiber bulked yarns

Abstract

The invention relates to a preparation method of a low-modulus high-adhesion wind power UD block using glass fiber bulked yarns, and belongs to the technical field of wind power blades, the preparation method comprises the following steps: S1, mixing epoxy resin, a curing agent, a filler and a processing aid with a non-polar group, and uniformly stirring to obtain a dipping solution; s2, glass fiber bulked yarns are soaked in a glue dipping tank, then preformed and heated and cured in a curing forming mold, and a pretreated UD block is obtained; and S3, cutting the pretreated UD block, and carrying out surface polishing treatment to obtain the finished UD block. The production method has the following beneficial effects that the UD block produced by using the glass fiber bulked yarns and the epoxy resin as main materials through a pultrusion process has the advantages that the UD block is high in strength and high in toughness, and the service life of the UD block is prolonged. The technical problems that in the prior art, the design strength of materials is high, the interface bonding strength of UD blocks and connecting areas is low, and the density of the UD blocks is large are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine blades, and in particular to a method for preparing a low-modulus and high-adhesion wind turbine UD block using bulked glass fiber yarn. Background Art

[0002] In the field of wind power generation, blades are one of the core components of wind turbines, and their design and manufacturing have a significant impact on the performance and efficiency of wind turbines. In the context of wind turbine blades, "UD" generally refers to areas made of unidirectional fiber material. This material is characterized by fibers arranged parallel in one direction, which can provide excellent strength and stiffness while reducing weight. In wind turbine blades, UD material is mainly used in areas that bear significant loads, such as the root of the blade.

[0003] In the existing technology, pultrusion-formed plates are generally used to prepare UD blocks for the roots of wind turbine blades. This process can effectively improve the tensile strength and elastic modulus of the material, greatly improve the firmness of the wind turbine blades, and make the blades less likely to deform. At the same time, it can overcome the quality problems such as wrinkles and interlayer bubbles that are prone to occur during the traditional vacuum introduction process of unidirectional cloth laying. Therefore, this process has been widely used by wind turbine blade manufacturers.

[0004] The pultruded UD blocks currently used in wind turbine blades are semi-finished products made of unidirectional fiber reinforced materials impregnated with resin matrix through pultrusion molding process, and then processed by bevel cutting, sandblasting / mold release cloth to obtain products with certain shapes and roughness. The density of the UD blocks currently in use is ≤2.16g / cm 3 , resin content ≥ 19%, surface roughness Ra ≥ 6.3 μm, 0° modulus ≥ 50 GPa, 0° tensile strength ≥ 800 MPa, V-shear strength ≥ 56 MPa, fracture toughness (GPC-mean IC-PROP) ≥ 200 J / ㎡. The fiberglass connecting the blade root to the UD block has a resin content of approximately 25% and a 0° modulus of approximately 40 GPa.

[0005] It can be seen that the design performance of the UD block is significantly higher than that of the fiberglass connected to it. The impact of this strength difference is multifaceted, mainly reflected in the following aspects:

[0006] When a blade is loaded, stress naturally flows to areas of greater rigidity and strength. If the UD block is significantly stronger than the surrounding material, these relatively weaker areas will experience greater stress.

[0007] The interface between the UD block and surrounding materials (such as the core material, composite materials of different layups, and adhesive joints) becomes a critical failure point. High stress can cause interfacial damage such as debonding, peeling, and shear failure, which is a common mode of blade failure.

[0008] UD blocks have high stiffness and are not easily deformed, which may cause local buckling of adjacent thin-walled structures (such as shell plates and webs) at or near the connection.

[0009] From a design perspective, the UD block has an excessive safety margin, while other areas lack sufficient safety margin, even becoming a bottleneck. This violates the principle of "equal strength distribution" in structural optimization design and fails to fully utilize material properties. Furthermore, because the UD block's strength is significantly higher than that of other areas, it can negatively impact the integrity of the blade.

[0010] The interface bonding strength between the UD block and the connection area is low, and the fracture toughness of the UD block is It can be concluded that the traditional sandblasting / stripping cloth process can no longer form higher interface performance.

[0011] High density, UD block density is 2.1g / cm 3 The weight of a single offshore blade using a UD block is 402KG. Since 2021, carbon fiber boards have gradually replaced glass fiber boards in the main beam structure of offshore wind turbine blades. Carbon fiber has a lower density, but its price is much higher than that of glass fiber.

[0012] Therefore, in response to the above technical problems, the patent of the present invention optimizes the performance design of the UD block, so that it has better adhesion and integrity with the joints, and provides a method for preparing a low-modulus and high-adhesion wind power UD block using glass fiber bulked yarn. Summary of the Invention

[0013] The purpose of the present invention is to provide a method for preparing a low-modulus and high-adhesion wind power UD using glass fiber bulked yarn. By using glass fiber bulked yarn and epoxy resin as the main materials and producing UD blocks through a pultrusion molding process, the technical problems existing in the prior art such as high design strength of the material itself, low interface bonding strength between the UD block and the connection area, and high density of the UD block are solved.

[0014] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn, comprising the following steps:

[0015] S1, mixing and stirring the epoxy resin, curing agent, filler and processing aid having a non-polar group to obtain a dipping solution;

[0016] S2, soaking the glass fiber bulked yarn in a dipping tank, preforming it, and heating and curing it in a curing mold to obtain a pretreated UD block;

[0017] S3. After the pre-processed UD block is cut, the surface is polished to obtain a finished UD block.

[0018] Preferably, in step S1,

[0019] The epoxy resin is bisphenol A epoxy resin;

[0020] The curing agent is one of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride;

[0021] The filler is aluminum hydroxide powder;

[0022] The processing aid is one of polyol and pentaerythritol.

[0023] Preferably, in step S2, the glass fiber bulked yarn is obtained by bulking alkali-free glass fiber, and the mass content of the glass fiber bulked yarn is not less than 30%.

[0024] Preferably, in step S2, during heating and curing, the temperature of the front zone of the curing molding mold is 135±10°C, the temperature of the middle zone is 165±10°C, and the temperature of the rear zone is 180±10°C.

[0025] Preferably, in step S3, the surface is polished using an electroplated diamond grinding wheel.

[0026] Preferably, in step S3, the surface is ground with a grinding wheel speed of 1200-2000 r / min.

[0027] Preferably, based on parts by mass, the composition includes 100 parts of epoxy resin, 90 parts of curing agent, 10 parts of filler, 2 parts of processing aid, and 285 parts of glass fiber bulked yarn.

[0028] A device for preparing low modulus and high adhesiveness wind power UD blocks using glass fiber bulked yarn, comprising pultrusion equipment and polishing equipment.

[0029] The pultrusion equipment includes a creel, a dipping tank, a preforming mold, a curing mold, a traction mechanism, and a cutter which are arranged in sequence;

[0030] The grinding equipment includes a motor, a grinding wheel, a fixed tooling, and a control box.

[0031] In summary, the present invention has the following beneficial effects:

[0032] 1. The present invention provides a method for preparing a low-modulus, high-adhesion wind power UD block using glass fiber bulked yarn. The method removes the release agent component in the original formula system and introduces a processing aid with a non-polar group. Under the condition of removing the release cloth and the release agent, the pultruded board can be smoothly demolded and the interface bonding performance of the UD block can be improved.

[0033] 2. The present invention provides a method for preparing a low-modulus, high-adhesion wind power UD block using glass fiber bulked yarn. Glass fiber bulked yarn is used instead of glass fiber unidirectional fiber. Since glass fiber bulked yarn has better impregnation and filling effects, the resin content of the UD block can be increased from 19% when using straight yarn to 40%; due to the increase in resin content, the density of the UD block can be increased from 2.1g / cm2 when using straight yarn. 3 Reduced to 1.8g / cm 3 ; Product density is reduced by 14%, and each blade is expected to reduce weight by about 50KG.

[0034] 3. The present invention provides a method for preparing a low-modulus and high-adhesion wind power UD block using glass fiber bulked yarn. By using glass fiber bulked yarn, the product can obtain a lower 0-degree modulus; since the bulked yarn has better wetting and filling properties, the fiber content of the product can be reduced, and the 0° modulus of the product is reduced accordingly.

[0035] 4. The present invention provides a method for preparing a low modulus and high adhesiveness wind power UD using glass fiber bulked yarn. Compared with the traditional surface treatment methods of UD blocks - sandblasting and demoulding cloth, a new surface treatment method - polishing is introduced. Compared with the surface treatment methods of sandblasting / demolding cloth, polishing can make the UD block have higher roughness and better interface bonding performance; and because the glass fiber bulked yarn is made by expanding unidirectional glass fiber, the simple unidirectional fiber will be disrupted during the expansion process, so that the fiber has a certain anisotropy, which further improves the interface bonding performance of the product and can make the UD fracture toughness from Increased to ≥1000J / ㎡. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of a pultrusion device for preparing wind power UD blocks in the present invention;

[0037] Figure 2 It is a schematic diagram of a surface grinding device for preparing wind power UD blocks in the present invention.

[0038] In the figure, 1-1, yarn rack; 1-2, dipping tank; 1-3, preforming mold; 1-4, curing molding mold; 1-5, traction mechanism; 1-6, cutter; 2-1, motor; 2-2, grinding wheel; 2-3, fixed tooling; 2-4, control box. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings.

[0040] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

[0041] Example:

[0042] A method for preparing a low-modulus, high-adhesion wind power UD block using a glass fiber bulked yarn comprises the following steps:

[0043] S1. Mix and stir an epoxy resin, a curing agent, a filler, and a processing aid having a non-polar group to obtain a dipping solution. The epoxy resin is bisphenol A epoxy resin; the curing agent is one of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride, with methyltetrahydrophthalic anhydride being used in this embodiment; the filler is aluminum hydroxide powder; and the processing aid is one of polyol and pentaerythritol, with polyol being used in this embodiment.

[0044] S2. After impregnation in a dipping tank containing adhesive, preform the fiberglass bulked yarn (abbreviated as fiberglass bulked yarn) and heat-cure it in a curing mold to obtain a pretreated UD block. The fiberglass bulked yarn is obtained by bulking alkali-free glass fiber, and the mass content of the fiberglass bulked yarn is not less than 30%. During the heating and curing process, the temperature of the front zone of the curing mold is 135±10°C, the temperature of the middle zone is 165±10°C, and the temperature of the rear zone is 180±10°C.

[0045] S3. Pre-processing After the UD block is cut, it is subjected to surface grinding to obtain a finished UD block. The surface grinding is performed using an electroplated diamond grinding wheel at a grinding wheel speed of 1200-2000 r / min.

[0046] This embodiment is a preparation device for a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn. Figure 1 and Figure 2 As shown, it includes pultrusion equipment and grinding equipment.

[0047] The pultrusion equipment includes a creel 1-1, a resin dipping tank 1-2, a preforming mold 1-3, a curing mold 1-4, a traction mechanism 1-5, and a cutter 1-6, which are arranged in this order. During processing, the glass fiber bulked yarn is drawn from the creel 1-1 and, under the traction of the traction mechanism 1-5, passes through the resin dipping tank 1-2, the preforming mold 1-3, the curing mold 1-4, and finally is cut by the cutter 1-6 to obtain pre-processed UD blocks.

[0048] The grinding equipment includes a motor 2-1, a grinding wheel 2-2, a fixed tool 2-3, and a control box 2-4. During processing, the fixed tool 2-3 is used to fix the pre-processed UD block, and after starting the motor 2-1, the grinding wheel 2-2 is used to grind the pre-processed UD block.

[0049] It should be noted that the pultrusion equipment and the grinding equipment are existing equipment. The innovation of the present invention lies in combining the two and applying them to the preparation of the UD block. Therefore, there is no unclear description.

[0050] Sample 1 was prepared using the method of this embodiment, and sample 2 was prepared using the prior art, and the two samples were compared as follows.

[0051] Preparation of Sample 1:

[0052] (1) preparing a dipping solution: uniformly mixing 100 parts by weight of epoxy resin, 90 parts by weight of epoxy curing agent, 10 parts by weight of filler, and 2 parts by weight of processing aid to obtain a dipping solution;

[0053] (2) Preparation of pre-treated UD blocks: pouring the dipping solution into the dipping tank 1, soaking 285 parts by weight of glass fiber bulked yarn in the dipping tank 1-2, pultruding at a speed of 1 m / min, sequentially entering the preforming mold 1-3 and the curing molding mold 1-4, and curing at high temperature to obtain a pre-treated plate, which was then cut into the required length;

[0054] (3) Obtaining the finished UD block: The cut pre-treated UD block is passed through a grinding device, and the surface is polished without a bright surface to form a finished product.

[0055] The performance of test sample 1 is shown in Table 1. The data are as follows:

[0056] According to ISO 1172, the resin mass content of the tested UD block is 43.18%;

[0057] According to ISO 1183-1, the density of the UD block is 1.734 g / cm 3 ;

[0058] According to ISO 11357-2, the TG of the test UD block is 105.79°C;

[0059] According to ISO 527-5, the 0° tensile modulus of the UD block is 32.37 GPa;

[0060] According to ISO 14126, the UD block 0° compression modulus is 32.55GPa;

[0061] According to ISO 14129, the V shear strength of the UD block tested is 64.09 MPa;

[0062] According to ASTM D5528, the fracture toughness of UD blocks was tested.

[0063] Preparation of Sample 2:

[0064] (1) preparing a dipping solution: uniformly mixing 100 parts by mass of epoxy resin, 100 parts by mass of epoxy curing agent, 10 parts by mass of filler, and 2 parts by mass of release agent to obtain a dipping solution;

[0065] (2) Preparation of pre-treated UD: the dipping solution is poured into the dipping tank 1, 888 parts by mass of glass fiber are soaked in the dipping tank 1-2, the pultrusion speed is 1 m / min, and the glass fiber enters the preforming mold 1-3 and the curing mold 1-4 in sequence, and is cured at high temperature to obtain a pre-treated sheet, which is then cut into the required length;

[0066] (3) Obtaining the finished UD block: The cut pre-treated UD block is passed through a sandblasting device, and the surface is sandblasted to form a finished product.

[0067] The performance of test sample 2 is shown in Table 1. The data are as follows:

[0068] According to ISO 1172, the resin mass content of the tested UD block is 22.46%;

[0069] According to ISO 1183-1, the density of the UD block is 2.069g / cm 3 ;

[0070] According to ISO 11357-2, the TG of the test UD block is 106.9°C;

[0071] According to ISO 527-5, the 0° tensile modulus of the UD block is 51.13 GPa;

[0072] According to ISO 14126, the UD block 0° compression modulus is 51.02GPa;

[0073] According to ISO 14129, the UD block V shear strength is 60.7MPa;

[0074] According to ASTM D5528, the fracture toughness of UD blocks was tested.

[0075] The preparation method of Sample 2 differs from that of Sample 1 in that: in step 1, the dipping solution and epoxy curing agent are prepared, and a release agent is used instead of a processing aid; in step 3, sandblasting is used instead of polishing.

[0076]

[0077]

[0078] Table 1 - Test results of glass fiber bulked yarn UD and currently widely used UD

[0079] As shown in Table 1, after testing, sample 2 has a higher resin content, lower density, similar TG, lower 0° tensile / compression modulus, higher V shear strength, and higher fracture toughness than sample 1. Greatly improved, higher interface bonding strength.

Claims

1. A method for preparing a low modulus and high adhesiveness wind power UD block using a glass fiber bulked yarn, characterized in that: The following steps are included: S1, mixing and stirring the epoxy resin, curing agent, filler and processing aid having a non-polar group to obtain a dipping solution; S2, soaking the glass fiber bulked yarn in a dipping tank, preforming it, and heating and curing it in a curing mold to obtain a pretreated UD block; S3. After the pre-processed UD block is cut, the surface is polished to obtain a finished UD block.

2. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 1, characterized in that: In step S1, The epoxy resin is bisphenol A epoxy resin; The curing agent is one of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride; The filler is aluminum hydroxide powder; The processing aid is one of polyol and pentaerythritol.

3. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 1, characterized in that: In step S2, the glass fiber bulked yarn is obtained by bulking the alkali-free glass fiber, and the mass content of the glass fiber bulked yarn is not less than 30%.

4. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 1, characterized in that: In step S2, during heating and curing, the temperature of the front zone of the curing molding die is 135±10°C, the temperature of the middle zone is 165±10°C, and the temperature of the rear zone is 180±10°C.

5. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 1, characterized in that: In step S3, the surface is polished using an electroplated diamond grinding wheel.

6. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 5, characterized in that: In step S3, the surface is ground, and the grinding wheel speed is 1200-2000 r / min.

7. The method for preparing a low modulus and high adhesiveness wind power UD block using glass fiber bulked yarn according to claim 1, characterized in that: Calculated by mass, the composition includes 100 parts of epoxy resin, 90 parts of curing agent, 10 parts of filler, 2 parts of processing aid and 285 parts of glass fiber bulked yarn.

8. A device for preparing low modulus and high adhesiveness wind power UD blocks using glass fiber bulked yarn, characterized in that: Including pultrusion equipment and grinding equipment, The pultrusion equipment includes a creel, a dipping tank, a preforming mold, a curing mold, a traction mechanism, and a cutter which are arranged in sequence; The grinding equipment includes a motor, a grinding wheel, a fixed tooling, and a control box.

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