Wind turbine blade manhole plate and manhole cover plate and preparation method and application thereof

Abstract

The application relates to the field of wind power blades, and discloses a wind power blade manhole plate and manhole cover plate as well as a preparation method and application thereof. The method comprises the following steps: (1) mixing unsaturated polyester resin, a thickening agent, an initiator, a crosslinking agent, a low shrinkage agent, a release agent, a polymerization inhibitor, an inorganic filler and waste glass fibers, and then filling the mixture into a mold for preheating; (2) performing mold pressing on the preheated material to obtain a preformed material; and (3) performing heat treatment on the preformed material, and then performing demolding to obtain the wind power blade manhole plate and manhole cover plate. The method is prepared by creatively adopting a mold pressing forming method, and waste glass fibers are used as raw materials for preparation, so that the preparation cost is saved, and the preparation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blades, specifically to a wind turbine blade manhole plate and manhole cover, their preparation method, and their application. Background Technology

[0002] As wind power enters an era of large-scale, rapid development and grid parity, its cost-competitiveness per kilowatt-hour is increasing, making it an important source of clean fuel and clean electricity. However, due to shrinking profit margins associated with grid parity, reducing manufacturing costs while maintaining quality is now the primary objective for wind power companies' operations and development.

[0003] Wind turbine blades, as they have evolved, all feature a hollow internal structure. Manhole plates and covers are typically installed at the blade tips. These plates not only prevent debris from entering the blade and enhance its strength, but the central opening allows passage for personnel. After installation, the manhole plates and covers are sealed with covers. Currently, the industry standard for manhole plates and covers is fiberglass reinforced plastic (FRP), which meets design requirements in terms of load-bearing capacity. However, this manufacturing process is slow, resulting in higher material costs. Furthermore, the current manufacturing process for manhole plates and covers generally employs manual injection, producing only about one set per day. This low production efficiency significantly impacts the overall production efficiency of wind turbine blades. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of high manufacturing cost and low manufacturing efficiency of wind turbine blade manhole plates and manhole covers in the prior art. This invention provides a wind turbine blade manhole plate and manhole cover, its manufacturing method and application. The method creatively adopts a compression molding method for manufacturing and uses waste glass fiber as raw material, which saves manufacturing cost and improves manufacturing efficiency.

[0005] To achieve the above objectives, the present invention provides a method for preparing a manhole plate and a manhole cover for wind turbine blades, the method comprising the following steps:

[0006] (1) Mix unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler and glass fiber, and then fill the mixture into the mold for preheating;

[0007] (2) The preheated material is molded to obtain a preformed material;

[0008] (3) The preformed material is heat-treated and then demolded to obtain the wind turbine blade manhole plate and manhole cover plate;

[0009] The unsaturated polyester resin content is 25-35 parts by weight and the glass fiber content is 55-62 parts by weight, relative to 100 parts by weight of the mixture.

[0010] Preferably, the preheating conditions include a temperature of 40-70°C and a time of 40-50 hours.

[0011] Preferably, the molding conditions include: molding pressure of 15-20 MPa, molding time of 10-30 min, and molding temperature of 125-145℃.

[0012] Preferably, the heat treatment conditions include a temperature of 50-70°C and a time of 45-55 hours.

[0013] Preferably, the thickener is magnesium oxide and / or lithium chloride.

[0014] Preferably, the unsaturated polyester resin is selected from phthalic unsaturated polyester resins and / or isophthalic unsaturated polyester resins.

[0015] Preferably, the glass fiber is added in the form of waste glass fiber.

[0016] Preferably, the initiator is tert-butyl peroxide and / or tert-butylperoxyisopropyl carbonate;

[0017] Preferably, the crosslinking agent is styrene and / or α-methylstyrene linear dimer;

[0018] Preferably, the low-shrinkage agent is a mixture of polystyrene and polymethyl methacrylate;

[0019] Preferably, the polymerization inhibitor is p-benzoquinone;

[0020] Preferably, the release agent is selected from one or more of stearic acid, oleic acid and paraffin.

[0021] Preferably, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin is 25-35 parts by weight, the content of the glass fiber is 55-62 parts by weight, the content of the thickener is 0.5-1 parts by weight, the content of the initiator is 0.5-1 parts by weight, the content of the crosslinking agent is 0.1-0.5 parts by weight, the content of the low-shrinkage agent is 3-8 parts by weight, the content of the release agent is 0.5-1 parts by weight, the content of the polymerization inhibitor is 0.02-0.1 parts by weight, and the content of the inorganic filler is 1-5 parts by weight.

[0022] Preferably, in the low-shrinkage agent, the weight ratio of polystyrene to polymethyl methacrylate is 1:1.2-1.8.

[0023] A second aspect of the present invention provides a manhole plate and a manhole cover plate for wind turbine blades prepared by the method described above.

[0024] A third aspect of the present invention provides the application of the manhole plate and manhole cover plate of the wind turbine blade in the manufacture of wind turbine blade units.

[0025] The method described in this invention uses glass fiber, unsaturated polyester resin, and inorganic fillers to prepare manhole plates and manhole covers for wind turbine blades, thus saving on manufacturing costs. Furthermore, this invention creatively employs a compression molding method, enabling continuous production using compression molding technology. This successfully overcomes the low efficiency problems associated with manual injection methods in existing technologies, significantly improving manufacturing efficiency and saving labor costs. It also achieves automated production of wind turbine blade manhole plates and covers, laying a solid foundation for the development of wind turbine blades. Moreover, this invention can also use waste glass fiber in the preparation process, further realizing the resource recycling of waste glass fiber.

[0026] Furthermore, the manhole plates and manhole covers for wind turbine blades prepared using the method described in this invention have an aesthetically pleasing appearance with few defects. Because the molding process utilizes high-temperature, high-pressure, and mechanized production, the product dimensions are stable, ensuring high reproducibility during mass production. The products are also easy to transport and install, lightweight, and exhibit stable properties, without deformation, bulging, or other damage. They demonstrate strong resistance to water immersion and freeze-thaw cycles, making them suitable for all-weather outdoor environments. Detailed Implementation

[0027] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] The method for preparing the manhole plate and manhole cover plate for wind turbine blades according to the present invention includes the following steps:

[0030] (1) Mix unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler and glass fiber, and then fill the mixture into the mold for preheating;

[0031] (2) The preheated material is molded to obtain a preformed material;

[0032] (3) The preformed material is heat-treated and then demolded to obtain the wind turbine blade manhole plate and manhole cover plate.

[0033] In a specific embodiment, the unsaturated polyester resin is selected from phthalic unsaturated polyester resin and / or isophthalic unsaturated polyester resin.

[0034] In the method described in this invention, the thickener is magnesium oxide and / or lithium chloride.

[0035] In some specific embodiments, the initiator is tert-butyl peroxide and / or tert-butylperoxyisopropyl carbonate.

[0036] In some specific embodiments, the crosslinking agent is styrene and / or α-methylstyrene linear dimer.

[0037] In some specific embodiments, the low-shrinkage agent is a mixture of polystyrene and polymethyl methacrylate.

[0038] In a preferred embodiment, the weight ratio of polystyrene to polymethyl methacrylate in the low-shrinkage agent is 1:1.2-1.8. Specifically, the weight ratio of polystyrene to polymethyl methacrylate can be 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, or 1:1.8.

[0039] In some specific embodiments, the polymerization inhibitor is p-benzoquinone.

[0040] In some specific embodiments, the release agent is selected from one or more of stearic acid, oleic acid, and paraffin wax.

[0041] In some specific embodiments, the inorganic filler is calcium carbonate.

[0042] In a preferred embodiment, the glass fiber is added in the form of waste glass fiber. Specifically, the waste glass fiber contains 70-90 wt% glass fiber, and the amount of waste glass fiber added is based on the weight of the glass fiber it contains. The waste glass fiber can come from one or more of waste wind turbine blades, waste chopped glass fiber, and waste glass fiber mat, and its specific source is not particularly limited. Furthermore, the components in the added waste wind turbine blades, other than glass fiber, will not negatively affect the reaction or will not participate in the reaction. Specifically, the manhole plate and manhole cover must have a certain load-bearing capacity, generally required to meet the requirement of bearing 300 kg. In this invention, by using waste glass fiber for preparation, not only is the strength of the waste glass fiber utilized to improve the strength of the prepared manhole plate, but the resource recycling of waste glass fiber is further realized, reducing the pressure on waste glass fiber processing.

[0043] In the method described in this invention, the unsaturated polyester resin can be a common unsaturated polyester resin in the art. Preferably, the unsaturated polyester resin is selected from orthophthalic unsaturated polyester resin and / or isophthalic unsaturated polyester resin.

[0044] In a preferred embodiment, the content of the unsaturated polyester resin is 25-35 parts by weight relative to 100 parts by weight of the mixture, and the content of the glass fiber is 55-62 parts by weight. That is, in the wind turbine blade manhole plate and manhole cover prepared herein, the unsaturated polyester resin and glass fiber are the main components. By further limiting the amount of unsaturated polyester resin and glass fiber, the strength of the prepared manhole plate and manhole cover can be further improved, resulting in the prepared manhole plate and manhole cover having better performance and being better applied to wind turbine units.

[0045] In a preferred embodiment, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin is 25-35 parts by weight, the content of the glass fiber is 55-62 parts by weight, the content of the thickener is 0.5-1 parts by weight, the content of the initiator is 0.5-1 parts by weight, the content of the crosslinking agent is 0.1-0.5 parts by weight, the content of the low-shrinkage agent is 3-8 parts by weight, the content of the release agent is 0.5-1 parts by weight, the content of the polymerization inhibitor is 0.02-0.1 parts by weight, and the content of the inorganic filler is 1-5 parts by weight.

[0046] In the method described in this invention, by further optimizing the molding process, the production efficiency of the manhole plate and manhole cover is improved, and the strength of the manhole plate and manhole cover is further improved, so that the prepared product meets its usage requirements.

[0047] In specific implementation methods, the quality and properties of the raw materials need to be studied before preparation. Materials with poor quality, fiber clumping, poor impregnation, or resin accumulation should be removed. Simultaneously, the raw materials are cut according to their structural shape and flow properties, and can be cut into rectangles or circles.

[0048] In a specific embodiment, in step (1), the obtained mixture is filled into the wind turbine blade manhole plate mold and the wind turbine blade manhole cover mold for preheating. Specifically, the wind turbine blade manhole plate mold and the wind turbine blade manhole cover mold can be prepared according to conventional techniques in the art, and will not be described in detail here.

[0049] In the method described in this invention, preheating the mixture can improve its processability, increase the temperature of the molding compound, thereby saving the heating time for subsequent molding, and simultaneously shortening the curing time and reducing the molding pressure. Preferably, the preheating conditions include: a temperature of 40-70℃, more preferably 45-55℃, and a time of 40-50 hours. Specifically, the preheating temperature can be 40℃, 50℃, 60℃, 65℃, or 70℃; and the preheating time can be 40 hours, 42 hours, 45 hours, 48 ​​hours, or 50 hours.

[0050] In a preferred embodiment, the molding conditions include: a molding pressure of 15-20 MPa, a molding time of 10-30 min, and a molding temperature of 125-145°C. Specifically, the molding pressure can be 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, or 20 MPa; the molding time can be 10 min, 15 min, 20 min, 25 min, or 30 min; and the molding temperature can be 125°C, 130°C, 135°C, 140°C, or 145°C.

[0051] In a specific implementation, heat treatment of the preformed material can make the curing more complete, while reducing the internal stress and volatiles of the material, which helps to improve the strength performance of the final wind turbine blade manhole plate and manhole cover.

[0052] In a preferred embodiment, the heat treatment conditions include: a temperature of 50-70°C, more preferably 55-65°C, and a time of 45-55 hours. Specifically, the heat treatment temperature can be 50°C, 55°C, 60°C, 65°C, or 70°C; and the heat treatment time can be 45 hours, 48 ​​hours, 50 hours, or 55 hours.

[0053] The method described in this invention allows for the simultaneous fabrication of manhole plates and manhole covers for multiple wind turbine blades using automated instruments. This avoids the inefficiencies associated with manual injection methods in existing technologies, significantly improving the production efficiency of wind turbine blade manhole plates and covers while also saving labor costs. Furthermore, the use of waste glass fiber as a raw material further reduces raw material costs, laying the foundation for the rapid and efficient production of wind turbine blade units.

[0054] This invention further provides a wind turbine blade manhole plate and manhole cover prepared by the above method. The wind turbine blade manhole plate and manhole cover possess excellent strength properties, high reproducibility, aesthetically pleasing appearance, and are easy to transport and install. They are also lightweight, exhibit stable sample properties, and will not deform, bulge, or suffer other damage. They are highly resistant to water immersion and freeze-thaw cycles, making them suitable for all-weather outdoor environments. They can bear a load of over 300 kg, fully meeting the usage requirements of wind turbine blade manhole plates and manhole covers, and can be well applied in the preparation of wind turbine blade units.

[0055] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0056] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0057] The waste glass fibers used in the following examples and comparative examples contain 86 wt% glass fiber and are sourced from a wind power plant in Liaoning Province.

[0058] The thickener used is magnesium oxide.

[0059] The initiator used was tert-butyl peroxide;

[0060] The crosslinking agent used is styrene;

[0061] The low-shrinkage agent used is obtained by mixing polystyrene and polymethyl methacrylate in a 1:2 ratio;

[0062] The polymerization inhibitor used is p-benzoquinone;

[0063] The release agent used is stearic acid;

[0064] The inorganic filler used is calcium carbonate.

[0065] Example 1

[0066] (1) A mixture of phthalic unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler and glass fiber is obtained. The mixture is then filled into a wind turbine blade manhole plate mold and a wind turbine blade manhole cover mold and preheated for 48 hours at a temperature of 45°C. The content of the unsaturated polyester resin is 32 parts by weight, the content of the glass fiber is 60 parts by weight, the content of the thickener is 0.6 parts by weight, the content of the initiator is 0.4 parts by weight, the content of the crosslinking agent is 0.3 parts by weight, the content of the low shrinkage agent is 5 parts by weight, the content of the release agent is 0.65 parts by weight, the content of the polymerization inhibitor is 0.05 parts by weight, and the content of the inorganic filler is 1 part by weight.

[0067] (2) The preheated material is molded at a temperature of 135℃, a pressure of 16MPa, and a time of 15min. After the molding is completed, a preformed material is obtained.

[0068] (3) The preformed material is heat-treated at 55°C for 46 hours, and then demolded. After demolding, the wind turbine blade manhole plate and manhole cover are prepared.

[0069] Example 2

[0070] (1) A mixture of isophthalic unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler, and waste glass fiber is obtained. The mixture is then filled into a wind turbine blade manhole plate mold and a wind turbine blade manhole cover mold and preheated for 45 hours at a temperature of 50°C. The mixture contains, relative to 100 parts by weight, 30 parts by weight of unsaturated polyester resin, 59 parts by weight of glass fiber (provided from waste glass fiber), 0.7 parts by weight of thickener, 0.6 parts by weight of initiator, 0.18 parts by weight of crosslinking agent, 4 parts by weight of low shrinkage agent, 0.5 parts by weight of release agent, 0.02 parts by weight of polymerization inhibitor, and 5 parts by weight of inorganic filler.

[0071] (2) The preheated material is molded at a temperature of 140°C, a pressure of 17MPa, and a time of 14min. After the molding is completed, a preformed material is obtained.

[0072] (3) The preformed material is heat-treated at 58°C for 48 hours, and then demolded. After demolding, the wind turbine blade manhole plate and manhole cover are prepared.

[0073] Example 3

[0074] (1) A mixture of phthalic unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler, and waste glass fiber is prepared. The mixture is then filled into a wind turbine blade manhole plate mold and a wind turbine blade manhole cover mold and preheated for 50 hours at a temperature of 55°C. Relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin is 30 parts by weight, the content of the glass fiber (provided by waste glass fiber) is 60 parts by weight, the content of the thickener is 0.5 parts by weight, the content of the initiator is 0.5 parts by weight, the content of the crosslinking agent is 0.4 parts by weight, the content of the low shrinkage agent is 5 parts by weight, the content of the release agent is 0.5 parts by weight, the content of the polymerization inhibitor is 0.1 parts by weight, and the content of the inorganic filler is 3 parts by weight.

[0075] (2) The preheated material is molded at a temperature of 140℃, a pressure of 18MPa, and a time of 18min. After the molding is completed, a preformed material is obtained.

[0076] (3) The preformed material is heat-treated at 60°C for 46 hours, and then demolded. After demolding, the wind turbine blade manhole plate and manhole cover are prepared.

[0077] Comparative Example 1

[0078] The method of Example 1 was implemented, except that the mixture obtained in step (1) was directly molded without preheating.

[0079] Comparative Example 2

[0080] The method of Example 1 was implemented, except that the heat treatment in step (3) was not performed.

[0081] Comparative Example 3

[0082] The method of Example 1 was implemented, except that, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin was 35 parts by weight, the content of the glass fiber was 52 parts by weight, the content of the thickener was 0.6 parts by weight, the content of the initiator was 0.6 parts by weight, the content of the crosslinking agent was 0.2 parts by weight, the content of the low-shrinkage agent was 6 parts by weight, the content of the release agent was 0.5 parts by weight, the content of the polymerization inhibitor was 0.1 parts by weight, and the content of the inorganic filler was 5 parts by weight.

[0083] Comparative Example 4

[0084] The method of Example 1 was implemented, wherein, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin was 25 parts by weight, the content of the glass fiber was 69 parts by weight, the content of the thickener was 0.6 parts by weight, the content of the initiator was 0.6 parts by weight, the content of the crosslinking agent was 0.2 parts by weight, the content of the low-shrinkage agent was 3 parts by weight, the content of the release agent was 0.5 parts by weight, the content of the polymerization inhibitor was 0.1 parts by weight, and the content of the inorganic filler was 1 part by weight.

[0085] Comparative Example 5

[0086] The method of Example 1 was implemented, except that, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin was 23 parts by weight, the content of the glass fiber was 62 parts by weight, the content of the thickener was 0.6 parts by weight, the content of the initiator was 0.6 parts by weight, the content of the crosslinking agent was 0.2 parts by weight, the content of the low-shrinkage agent was 8 parts by weight, the content of the release agent was 0.5 parts by weight, the content of the polymerization inhibitor was 0.1 parts by weight, and the content of the inorganic filler was 5 parts by weight.

[0087] Comparative Example 6

[0088] The method of Example 1 was implemented, except that, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin was 38 parts by weight, the content of the glass fiber was 56 parts by weight, the content of the thickener was 0.6 parts by weight, the content of the initiator was 0.6 parts by weight, the content of the crosslinking agent was 0.2 parts by weight, the content of the low-shrinkage agent was 3 parts by weight, the content of the release agent was 0.5 parts by weight, the content of the polymerization inhibitor was 0.1 parts by weight, and the content of the inorganic filler was 1 part by weight.

[0089] Test case

[0090] The wind turbine blade manhole plates and manhole covers prepared in Examples 1-3, as well as the materials prepared in Comparative Examples 1-6, were subjected to strength performance tests.

[0091] The strength of the samples was tested according to the method of GB / T1449-2005 standard, and the test results are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] As can be seen from the results in Table 1, the manhole plates and manhole covers for wind turbine blades prepared by the method described in this invention have excellent bending performance, which can meet the strength requirements of the manhole plates and manhole covers for wind turbine blades, and can achieve fully automated preparation, which improves production efficiency and saves preparation costs at the same time.

[0096] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a manhole plate and manhole cover for wind turbine blades, characterized in that, The method includes the following steps: (1) Mix unsaturated polyester resin, thickener, initiator, crosslinking agent, low shrinkage agent, release agent, polymerization inhibitor, inorganic filler and glass fiber to obtain a mixture, and then fill the mixture into a mold for preheating; (2) The preheated material is molded to obtain a preformed material; (3) The preformed material is heat-treated and then demolded to obtain the wind turbine blade manhole plate and manhole cover plate; Of which, relative to 100 parts by weight of the mixture, the content of the unsaturated polyester resin is 25-35 parts by weight, the content of the glass fiber is 55-62 parts by weight, the content of the thickener is 0.5-1 parts by weight, the content of the initiator is 0.5-1 parts by weight, the content of the crosslinking agent is 0.1-0.5 parts by weight, the content of the low-shrinkage agent is 3-8 parts by weight, the content of the release agent is 0.5-1 parts by weight, the content of the polymerization inhibitor is 0.02-0.1 parts by weight, and the content of the inorganic filler is 1-5 parts by weight; The unsaturated polyester resin is selected from orthophthalic unsaturated polyester resin and / or isophthalic unsaturated polyester resin; The glass fiber is added in the form of waste glass fiber, which contains 70-90 wt% glass fiber. The molding conditions include: molding pressure of 15-20 MPa, time of 10-30 min, and molding temperature of 125-145℃; the heat treatment conditions include: temperature of 50-70℃ and time of 45-55 h.

2. The method according to claim 1, characterized in that, The preheating conditions include a temperature of 40-70℃ and a time of 40-50 hours.

3. The method according to claim 1, characterized in that, The thickener is magnesium oxide and / or lithium chloride.

4. The method according to claim 1, characterized in that, The initiator is tert-butyl peroxide and / or tert-butylperoxide isopropyl carbonate.

5. The method according to claim 1, characterized in that, The crosslinking agent is styrene and / or α-methylstyrene linear dimer.

6. The method according to claim 1, characterized in that, The low-shrinkage agent is a mixture of polystyrene and polymethyl methacrylate.

7. The method according to claim 1, characterized in that, The polymerization inhibitor is p-benzoquinone.

8. The method according to claim 1, characterized in that, The release agent is selected from one or more of stearic acid, oleic acid and paraffin.

9. The method according to claim 6, characterized in that, In the low-shrinkage agent, the weight ratio of polystyrene to polymethyl methacrylate is 1:1.2-1.

8.

10. The wind turbine blade manhole plate and manhole cover plate prepared by the method of any one of claims 1-9.

11. The application of the wind turbine blade manhole plate and manhole cover plate as described in claim 10 in the manufacture of wind turbine blade units.

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