A recycled board made of highly filled modified waste wind turbine blade powder and its preparation method

Abstract

The present invention belongs to the technical field of recycling and reusing waste wind turbine blades and preparing recycled board materials. It discloses a recycled board material made from highly filled modified waste wind turbine blade powder and a preparation method thereof. The preparation method comprises adding crushed waste wind turbine blade products to a millstone-shaped solid-phase force chemical reactor for grinding and pulverization, modifying the collected wind turbine blade powder by selectively utilizing a silane coupling agent KH560, and selectively using a PMDI adhesive to blend and mold the board material. Under the above-mentioned specific combined treatment process conditions, the present invention can achieve an ultra-high filling of 90 wt% of waste wind turbine blade powder and effectively improve the mechanical properties of the recycled board material produced. The recycled board material has good density, mechanical properties, and hardness, significantly exceeding the performance of traditional artificial board products, and meets the technical requirements of formaldehyde-free environmentally friendly materials, providing a new approach for the large-scale recycling and utilization of retired wind turbine blades.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling and reusing waste wind turbine blades and preparing regenerated plates, and specifically relates to a regenerated plate made of highly filled modified waste wind turbine blade powder and a preparation method thereof, especially for using an industrial grinding disc-shaped solid phase force chemical reactor disclosed in Chinese invention patent CN114534660B to process waste wind turbine blades as the main raw material for regenerated plates. Background Art

[0002] Rapid socioeconomic development and continued global population growth have driven a surge in demand for energy and fuel. Unsustainable consumption of fossil fuels (coal, oil, and natural gas) poses a major global energy challenge, making the development and deployment of new renewable energy sources a global research focus. Renewable energy technologies such as wind, solar, and geothermal have experienced rapid development in recent years. Wind power, due to its clean, efficient, and sustainable nature, has experienced rapid growth since 2000, becoming one of the most mature power generation methods. However, the large number of retired wind turbine blades, representing a new type of solid waste and difficult to recycle, has drawn widespread attention.

[0003] The core technical bottleneck in wind turbine blade recycling lies in the irreversible nature of the thermosetting resins used. This stems from the widespread use of epoxy resin as a matrix in wind turbine blade manufacturing. Its curing and crosslinking reactions form a three-dimensional network structure with the following characteristics: 1) strong structural stability and excellent heat resistance; 2) impeded molecular segment movement, making it impossible to reshape using conventional thermal processing methods; and 3) high chemical bond dissociation energy, making it difficult to break with conventional solvents. These characteristics result in low added value for recycled products from traditional mechanical recycling methods, while chemical depolymerization faces technical and economic barriers such as high energy consumption and expensive catalyst costs, severely restricting its industrial application prospects.

[0004] The vast majority of wind turbine blade disposal methods, both domestically and internationally, are incineration or landfill. Incineration produces large amounts of CO and CO₂, polluting the atmosphere. High-temperature recycled glass fiber degrades in performance and reduces its value. China and some European countries have already banned the incineration of retired blades. However, landfilling can affect arable land and cause groundwater problems, so landfilling wind turbine blades should be avoided whenever possible.

[0005] Theoretically, the optimal recycling method for retired wind turbine blades is to obtain recycled products with the same properties as the original materials in a cost-effective and environmentally friendly manner. This involves recovering fibers, fillers, and resins from discarded wind turbine blades. Currently, three common recycling methods for discarded wind turbine blades have been reported: pyrolysis, chemical (solvent decomposition), and physical (mechanical) recycling. While pyrolysis can achieve both energy and material recovery, it is limited by technical and economic bottlenecks such as the high investment in high-temperature reaction equipment and high operating energy consumption. Furthermore, wind turbine blades generally use glass fiber as a reinforcing fiber, which exhibits more severe performance loss than carbon fiber at high temperatures, making its market adoption challenging. Chemical recycling holds great promise, but due to technical and cost limitations, it remains in the experimental stage and requires continued research and development. Physical recycling is more mature and has been commercialized in glass fiber composites. However, conventional physical recycling suffers from issues such as large particle size and poor phase domain formation, resulting in poor performance and low value of the recycled products, hindering their practical application.

[0006] In recent years, researchers have also explored new approaches to recycling waste wind turbine blades, using them as raw materials to produce high-performance recycled products, achieving some success. For example, the inventors of this invention previously applied for a patent, "Fiberglass Recycled Products Using Waste Wind Turbine Blades as Raw Materials and Preparation Methods Thereof" (CN118063854A), which discloses a fiberglass recycled product using waste wind turbine blades as raw materials and a preparation method thereof. The patent first provides a method for preparing highly compatible and reactive fillers from waste wind turbine blades. After pretreatment, the waste wind turbine blades are added to a disc-type solid-phase force chemical reactor for grinding and pulverizing to produce ultrafine wind turbine blade powder. The ultrafine wind turbine blade powder is then mixed with an activator and co-milled to produce a highly compatible and reactive filler. This highly compatible and reactive filler is then used as a partial raw material to prepare the fiberglass recycled products.

[0007] However, in the implementation and transformation evaluation of the above-mentioned patented technology-related topics, it is still reflected that when the patented technology is used to prepare recycled products with good performance, the proportion of discarded wind turbine blades in its raw materials has objective limitations due to the irreversible characteristics of thermosetting resins. This seriously restricts the number and scale of discarded wind turbine blades that can be recycled and processed during the implementation of the patented technology.

[0008] Therefore, it is urgent to develop new methods and technologies for the recycling of retired wind turbine blades and to build a green recycling and processing industry that can meet the needs of a large number of discarded wind turbine blades. Summary of the Invention

[0009] In order to solve the problems in the above-mentioned prior art, the present invention provides a recycled board material made from highly filled modified waste wind turbine blade powder and a preparation method thereof. The preparation method grinds the waste wind turbine blades into powder based on solid-phase shear milling technology, and then selectively utilizes the silane coupling agent KH560 for modification, and optionally uses a PMDI adhesive for blending and molding the board material. Under the above-mentioned specific combined processing conditions, the present invention can achieve an ultra-high filling of 90 wt% of waste wind turbine blade powder, and effectively improve the mechanical properties of the recycled board material obtained, with good density, mechanical properties and hardness, significantly exceeding the performance of traditional artificial board products, and meeting the technical requirements of formaldehyde-free environmentally friendly materials, providing a new approach for the large-scale recycling and utilization of retired wind turbine blades.

[0010] In order to achieve the above-mentioned objectives, the present invention is implemented by adopting a technical solution consisting of the following technical measures.

[0011] The present invention provides a method for preparing a recycled plate from highly filled modified waste wind turbine blade powder, which mainly comprises the following steps:

[0012] (1) After pre-treatment including cleaning, the discarded wind turbine blade products are crushed into wind turbine blade fragments with an average particle size of no more than 8 mm;

[0013] (2) adding the wind turbine blade fragments obtained in step (1) into a millstone-shaped solid phase force chemical reactor for grinding and pulverizing, and collecting the wind turbine blade powder after the grinding is completed; wherein, the process parameters of the millstone-shaped solid phase force chemical reactor are: grinding pressure of 5-10 MPa, introduction of -16-0 ° C circulating cooling liquid to control the temperature of the millstone surface, cyclic grinding for 1-2 times, and a millstone speed of 40-50 rpm;

[0014] (3) Immersing the wind turbine blade powder obtained in step (2) in a 3-6% mass concentration of a silane coupling agent KH560 aqueous solution, accompanied by stirring, and filtering and drying after 30-60 minutes to obtain a modified wind turbine blade powder;

[0015] (4) The modified wind turbine blade powder obtained in step (3) is used as the main raw material, and the raw materials including the following components are mixed evenly by weight to form a mixed base material:

[0016] 80~90 parts of modified wind turbine blade powder,

[0017] 10~20 parts of PMDI adhesive,

[0018] Wherein, the modified wind turbine blade powder and PMDI adhesive total 100 parts;

[0019] (5) Pour the mixed base material obtained in step (4) into a mold and prepare a recycled board by hot pressing.

[0020] In this article, the pretreatment including washing described in step (1) is mainly to remove impurities on the surface of the discarded wind turbine blade products. If necessary, the non-wind turbine blade parts need to be removed. Those skilled in the art can carry out specific treatment according to the actual conditions of the discarded wind turbine blade products that need to be recycled and based on the existing technology.

[0021] In this article, the wind turbine blade fragments processed and crushed to an average particle size of not more than 8 mm in step (1) can be processed and crushed in a conventional crushing manner in order to facilitate the placement of the fragments into a disc-shaped solid-phase force chemical reactor for grinding, such as by using existing conventional crushing equipment such as a jaw crusher, a planetary ball mill, and a frozen ball mill.

[0022] In this article, the millstone-shaped solid-phase force chemical reactor in step (2) is the industrial millstone-shaped solid-phase force chemical reactor disclosed in the prior invention patent CN114534660B of the applicant of the present invention.

[0023] It should be noted that this industrial millstone-shaped solid-phase force chemical reactor is based on the principle of the force chemical reactor disclosed in the previously authorized patent ZL95111258.9, and is the final improved industrial equipment. It is significantly different from the structure of the laboratory prototype when ZL95111258.9 was applied for. A new millstone structure is designed for industrial high-efficiency force chemical grinding treatment. The previous vertical setting of the millstone is improved to a horizontal setting, and the size of the millstone is greatly increased. Based on the horizontal setting and large size of the millstone, the relevant fixed millstone components and hydraulic lifting system are innovatively designed, which greatly improves its three-dimensional shear force.

[0024] Generally, the actual operation of the above-mentioned cyclic milling process is to grind the material through a millstone-shaped solid phase force chemical reactor, collect the product at the discharge end and place it again in a millstone-shaped solid phase force chemical reactor for grinding treatment. The above process is regarded as one cyclic milling.

[0025] In this article, in step (2), a circulating cooling liquid at -16 to 0 °C is introduced to control the temperature of the grinding disc surface, and the cooling liquid is water, ethylene glycol or glycerol.

[0026] The technical purpose of the present invention is to recycle and utilize discarded wind turbine blades in a high-value and scalable manner. Based on this technical purpose, the technical solution of the present invention is based on the previously applied invention patent "Fiberglass recycled products using discarded wind turbine blades as raw materials and their preparation method" (CN118063854A), and focuses on how to use discarded wind turbine blade powder as the main raw material in recycled products.

[0027] During the technical exploration process, the inventors found that under the ultra-fine particle size conditions of the powder after solid-phase shear milling technology, the adhesives commonly used in artificial boards were blended and hot-pressed to form boards, and the waste wind turbine blade powder was coated with adhesives to achieve the preparation of processable recycled boards.

[0028] However, even if sufficient adhesive is added to ensure processability, the mechanical properties of the resulting recycled board still have certain limitations. This is also the main reason why the filling content in recycled products prepared from discarded wind turbine blades was generally not high in the past.

[0029] In order to solve the above problems, the inventors designed a series of orthogonal experiments based on the characteristics that wind turbine blades mainly use epoxy resin as the matrix, tried to use different silane coupling agents for modification, and mixed the modified wind turbine blade powder with different adhesives for hot pressing to make boards.

[0030] It should be noted that during the test, after preliminary comparison, silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH590 were selected for modification, and PMDI adhesive, phenolic resin adhesive, urea-formaldehyde resin adhesive, melamine formaldehyde resin adhesive and epoxy resin adhesive were selected for blending and hot pressing to make boards.

[0031] Conventional wisdom suggests that although wind turbine blades primarily utilize epoxy resin as their matrix, since the epoxy resin in discarded wind turbine blades is already crosslinked and cured, it is generally believed that modification with the silane coupling agent KH550 is more effective. Furthermore, when using the silane coupling agent KH550, the amino groups (-NH2) on the powder surface can directly react with the -NCO groups in the subsequent PMDI adhesive, forming strong urea bonds (-NH-CO-NH-). This reaction is fast and has high bond energy. In contrast, the hydroxyl groups (-OH) generated by epoxy modification with the silane coupling agent KH560 react with the -NCO groups to form urethane bonds (-NH-CO-O-). This reaction is less reactive than direct amino group reactions and has a lower bond energy. When choosing an adhesive, the silane coupling agent KH560 and epoxy resin adhesive are generally considered a preferred combination based on their reaction mechanisms.

[0032] However, based on the test results, the inventors were surprised to find that by choosing to use silane coupling agent KH560 for modification and using PMDI adhesive to blend and mold the board, the strength and modulus of the recycled board were significantly improved, and were significantly better than other comparative test groups. The comprehensive performance was far higher than the industry standard, achieving unexpected test results.

[0033] In addition, when the silane coupling agent KH560 is used for modification and PMDI adhesive is used for blending and molding the board, the hardness of the recycled board is significantly improved.

[0034] Moreover, the above excellent performance is based on the premise that the mass proportion of modified wind turbine blade powder is 90%, providing a high-value, high-performance recycled product preparation and utilization method for discarded wind turbine blades.

[0035] In one of the technical solutions, in order to make the modification more complete, the wind turbine blade powder in step (3) is immersed in a silane coupling agent KH560 aqueous solution with a mass concentration of 3~6%, and the feed ratio of wind turbine blade powder to silane coupling agent KH560 is preferably (80~95): (5~20).

[0036] In this article, the mixed base material described in step (5) is poured into a mold and hot-pressed to prepare a recycled board, wherein the process steps / conditions / parameters of the hot-pressing can refer to the conventional preparation process of artificial boards in the prior art.

[0037] In order to better illustrate the present invention and provide a technical solution for reference, the recycled board is prepared by hot pressing in step (5), wherein the process parameters of the hot pressing are specifically: temperature 170~180℃, pressure 12~15MPa, and hot pressing 15~20min.

[0038] In this article, the filtering, drying and mixing are all in accordance with conventional principles in chemical processes, and those skilled in the art can perform specific operations according to common knowledge.

[0039] The present invention has the following beneficial effects:

[0040] (1) The present invention provides a recycled board made of highly filled modified waste wind turbine blade powder and a method for preparing the same. The method firstly achieves ultrafine grinding of the waste wind turbine blades by the intense three-dimensional shear force of a millstone-shaped solid phase mechanochemical reactor, then modifies the wind turbine blade powder using a silane coupling agent KH560, and optionally uses a PMDI adhesive to blend and mold the board. Under the above-mentioned specific combined processing conditions, the present invention can achieve an ultra-high filling of 90wt% of waste wind turbine blade powder, and effectively improve the mechanical properties of the recycled board obtained, with good density, mechanical properties and hardness, and significantly exceeding the performance of traditional artificial board products.

[0041] (2) The present invention provides a recycled board made of highly filled modified waste wind turbine blade powder and a preparation method thereof. During the preparation process, unlike traditional physical bonding, the hydroxyl functional groups on the surface of the modified wind turbine blade powder and the isocyanate groups in the PMDI adhesive undergo a chemical reaction, which greatly improves the mechanical properties of the artificial board.

[0042] (3) The technical solution of the present invention uses waste wind turbine blades as the main raw material and can achieve high filling recovery. Different from the existing recycling technology with too low recovery rate, it can recycle waste wind turbine blades more efficiently, with a recovery rate of up to 90 wt%.

[0043] (4) The technical solution of the present invention is not only simple to operate, has low recycling costs, and is easy to mass-produce, but also does not generate any waste during the recycling process and does not cause secondary pollution. The recycled board obtained by the final molding process has excellent mechanical properties and can be used as a similar alternative product, with clear industrial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the process flow of the preparation method of Example 1 of the present invention.

[0045] Figure 2 The infrared spectra (a) and thermogravimetric comparison diagrams (b) of the wind turbine blade powder obtained in step (2) of Example 1 and Comparative Examples 1 and 2 of the present invention and the modified wind turbine blade powder obtained in step (3) are shown. WTB refers to the wind turbine blade powder obtained in step (2), and WTB-KH550, WTB-KH560, and WTB-KH590 correspond to the modified wind turbine blade powder obtained in step (3) of Comparative Example 1, Example 1, and Comparative Example 2, respectively.

[0046] Figure 3 The figures are comparative diagrams of the particle sizes of the wind turbine blade powder obtained in step (2) of Example 1 and Comparative Examples 1-2 of the present invention and the modified wind turbine blade powder obtained in step (3). Figure (a) is a particle size distribution diagram of the wind turbine blade powder obtained in step (2) of Example 1 and Comparative Examples 1-2, Figure (b) is a particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) of Comparative Example 1, Figure (c) is a particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) of Example 1, and Figure (d) is a particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) of Comparative Example 2.

[0047] Figure 4 The following is a comparison of the tensile strength of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5. Figure (a) shows the stress-strain curves of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5, and Figure (b) shows the tensile strength and modulus of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5. Pure corresponds to the sample in Comparative Example 5.

[0048] Figure 5The following is a comparison of the flexural strength of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5. Figure (a) shows the stress-strain curves of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5, and Figure (b) shows the flexural strength and modulus of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5. Pure corresponds to the sample in Comparative Example 5.

[0049] Figure 6 The following is a comparison chart of the Rockwell hardness of the recycled boards prepared in Example 1, Comparative Examples 1-2, and Comparative Example 5. Pure corresponds to the sample in Comparative Example 5, while KH550, KH560, and KH590 correspond to the samples prepared in Comparative Example 1, Example 1, and Comparative Example 2, respectively.

[0050] Figure 7 This is a gas chromatography-mass spectrometry diagram of the Soxhlet extract of the regenerated board prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0051] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than for limiting the claims of the invention. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters for implementation. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Although it is believed that those of ordinary skill in the art fully understand the following terms, the following definitions are still stated to help illustrate the subject matter disclosed by the present invention.

[0052] The present invention provides a method for preparing a recycled plate from highly filled modified waste wind turbine blade powder, which mainly comprises the following steps:

[0053] (1) After pre-treatment including cleaning, the discarded wind turbine blade products are crushed into wind turbine blade fragments with an average particle size of no more than 8 mm;

[0054] (2) adding the wind turbine blade fragments obtained in step (1) into a millstone-shaped solid phase force chemical reactor for grinding and pulverizing, and collecting the wind turbine blade powder after the grinding is completed; wherein, the process parameters of the millstone-shaped solid phase force chemical reactor are: grinding pressure of 5-10 MPa, introduction of -16-0 ° C circulating cooling liquid to control the temperature of the millstone surface, cyclic grinding for 1-2 times, and a millstone speed of 40-50 rpm;

[0055] (3) Immersing the wind turbine blade powder obtained in step (2) in a 3-6% mass concentration of a silane coupling agent KH560 aqueous solution, accompanied by stirring, and filtering and drying after 30-60 minutes to obtain a modified wind turbine blade powder;

[0056] (4) The modified wind turbine blade powder obtained in step (3) is used as the main raw material, and the raw materials including the following components are mixed evenly by weight to form a mixed base material:

[0057] 80~90 parts of modified wind turbine blade powder,

[0058] 10~20 parts of PMDI adhesive,

[0059] Wherein, the modified wind turbine blade powder and PMDI adhesive total 100 parts;

[0060] (5) Pour the mixed base material obtained in step (4) into a mold and prepare a recycled board by hot pressing.

[0061] In this article, the pretreatment including washing described in step (1) is mainly to remove impurities on the surface of the discarded wind turbine blade products. If necessary, the non-wind turbine blade parts need to be removed. Those skilled in the art can carry out specific treatment according to the actual conditions of the discarded wind turbine blade products that need to be recycled and based on the existing technology.

[0062] In this article, the wind turbine blade fragments processed and crushed to an average particle size of not more than 8 mm in step (1) can be processed and crushed in a conventional crushing manner to facilitate the placement of the fragments in a disc-shaped solid-phase force chemical reactor for grinding. In one embodiment, the fragments are processed by conventional crushing equipment such as a jaw crusher, a planetary ball mill, and a frozen ball mill.

[0063] In this article, the millstone-shaped solid-phase force chemical reactor in step (2) is the industrial millstone-shaped solid-phase force chemical reactor disclosed in the prior invention patent CN114534660B of the applicant of the present invention.

[0064] It should be noted that this industrial millstone-shaped solid-phase force chemical reactor is based on the principle of the force chemical reactor disclosed in the previously authorized patent ZL95111258.9, and is the final improved industrial equipment. It is significantly different from the structure of the laboratory prototype when ZL95111258.9 was applied for. A new millstone structure is designed for industrial high-efficiency force chemical grinding treatment. The previous vertical setting of the millstone is improved to a horizontal setting, and the size of the millstone is greatly increased. Based on the horizontal setting and large size of the millstone, the relevant fixed millstone components and hydraulic lifting system are innovatively designed, which greatly improves its three-dimensional shear force.

[0065] Generally, the actual operation of the above-mentioned cyclic milling process is to grind the material through a millstone-shaped solid phase force chemical reactor, collect the product at the discharge end and place it again in a millstone-shaped solid phase force chemical reactor for grinding treatment. The above process is regarded as one cyclic milling.

[0066] In this article, in step (2), a circulating cooling liquid at -16 to 0 °C is introduced to control the temperature of the grinding disc surface. In one embodiment, the cooling liquid is water, ethylene glycol or glycerol.

[0067] The technical purpose of the present invention is to recycle and utilize discarded wind turbine blades in a high-value and scalable manner. Based on this technical purpose, the technical solution of the present invention is based on the previously applied invention patent "Fiberglass recycled products using discarded wind turbine blades as raw materials and their preparation method" (CN118063854A), and focuses on how to use discarded wind turbine blade powder as the main raw material in recycled products.

[0068] During the technical exploration process, the inventors found that under the ultra-fine particle size conditions of the powder after solid-phase shear milling technology, the adhesives commonly used in artificial boards were blended and hot-pressed to form boards, and the waste wind turbine blade powder was coated with adhesives to achieve the preparation of processable recycled boards.

[0069] However, even if sufficient adhesive is added to ensure processability, the mechanical properties of the resulting recycled board still have certain limitations. This is also the main reason why the filling content in recycled products prepared from discarded wind turbine blades was generally not high in the past.

[0070] In order to solve the above problems, the inventors designed a series of orthogonal experiments based on the characteristics that wind turbine blades mainly use epoxy resin as the matrix, tried to use different silane coupling agents for modification, and mixed the modified wind turbine blade powder with different adhesives for hot pressing to make boards.

[0071] It should be noted that during the test, after preliminary comparison, silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH590 were selected for modification, and PMDI adhesive, phenolic resin adhesive, urea-formaldehyde resin adhesive, melamine formaldehyde resin adhesive and epoxy resin adhesive were selected for blending and hot pressing to make boards.

[0072] Conventional wisdom suggests that although wind turbine blades primarily utilize epoxy resin as their matrix, since the epoxy resin in discarded wind turbine blades is already crosslinked and cured, it is generally believed that modification with the silane coupling agent KH550 is more effective. Furthermore, when using the silane coupling agent KH550, the amino groups (-NH2) on the powder surface can directly react with the -NCO groups in the subsequent PMDI adhesive, forming strong urea bonds (-NH-CO-NH-). This reaction is fast and has high bond energy. In contrast, the hydroxyl groups (-OH) generated by epoxy modification with the silane coupling agent KH560 react with the -NCO groups to form urethane bonds (-NH-CO-O-). This reaction is less reactive than direct amino group reactions and has a lower bond energy. When choosing an adhesive, the silane coupling agent KH560 and epoxy resin adhesive are generally considered a preferred combination based on their reaction mechanisms.

[0073] However, based on the test results, the inventors were surprised to find that by choosing to use silane coupling agent KH560 for modification and using PMDI adhesive to blend and mold the board, the strength and modulus of the recycled board were significantly improved, and were significantly better than other comparative test groups. The comprehensive performance was far higher than the industry standard, achieving unexpected test results.

[0074] In addition, when the silane coupling agent KH560 is used for modification and PMDI adhesive is used for blending and molding the board, the hardness of the recycled board is significantly improved.

[0075] Moreover, the above excellent performance is based on the premise that the mass proportion of modified wind turbine blade powder is 90%, providing a high-value, high-performance recycled product preparation and utilization method for discarded wind turbine blades.

[0076] In one embodiment, the mass concentration of the silane coupling agent KH560 aqueous solution in step (3) is 3% to 6%, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6% or any range or point value therebetween.

[0077] In one embodiment, in order to make the modification more sufficient, the wind turbine blade powder in step (3) is immersed in a silane coupling agent KH560 aqueous solution with a mass concentration of 3~6%, and the feed ratio of wind turbine blade powder to silane coupling agent KH560 is preferably (80~95):(5~20), for example, 80:5, 80:10, 80:15, 80:20, 85:5, 85:10, 85:15, 85:20, 90:5, 90:10, 90:15, 90:20, 95:5, 95:10, 95:15, 95:20 or any range or point value therebetween.

[0078] In this article, the mixed base material described in step (5) is poured into a mold and hot-pressed to prepare a recycled board, wherein the process steps / conditions / parameters of the hot-pressing can refer to the conventional preparation process of artificial boards in the prior art.

[0079] In order to better illustrate the present invention and provide a technical solution for reference, the recycled board is prepared by hot pressing in step (5), wherein the process parameters of the hot pressing are specifically: temperature 170~180℃, pressure 12~15MPa, and hot pressing 15~20min.

[0080] In this article, the filtering, drying and mixing are all in accordance with conventional principles in chemical processes, and those skilled in the art can perform specific operations according to common knowledge.

[0081] The present invention will be further explained in detail below with reference to the examples. However, it will be appreciated by those skilled in the art that these examples are provided for illustrative purposes only and are not intended to limit the present invention.

[0082] Example

[0083] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if no specific conditions are indicated, the conditions are carried out according to normal conditions or manufacturer recommendations. The reagents used or the instruments that are not indicated by the manufacturer are conventional products that can be obtained commercially. The application should not be construed as being limited to the specific examples described.

[0084] 1. Raw materials

[0085] Waste (retired) wind turbine blades are waste and residues from wind turbine blades, provided by Tianjin Longjin Energy Saving Technology Co., Ltd.

[0086] Silane coupling agents (KH550, KH560, KH590, purity 98%) were provided by Chengdu Kelong Chemical Co., Ltd.

[0087] PMDI (polyisocyanate) adhesive, provided by Wanhua Chemical Group Co., Ltd.;

[0088] Epoxy resin (EP-128), provided by Chengdu Kemite Technology Co., Ltd.;

[0089] Water-based phenolic resin was provided by Jinan Dahui Chemical Technology Co., Ltd.

[0090] 2. Preparation method

[0091] (1) After pre-treatment including cleaning, the discarded wind turbine blade products are crushed into wind turbine blade fragments with an average particle size of 6 mm;

[0092] (2) Adding the wind turbine blade fragments obtained in step (1) into a millstone-shaped solid phase force chemical reactor for grinding and pulverization, and collecting the wind turbine blade powder after the grinding is completed; wherein the process parameters of the millstone-shaped solid phase force chemical reactor are: grinding pressure of 5 MPa, introduction of -15 ° C circulating cooling liquid to control the temperature of the millstone surface, cyclic grinding once, and a millstone speed of 50 rpm;

[0093] (3) Immersing the wind turbine blade powder obtained in step (2) in a 3% mass concentration of a silane coupling agent KH560 aqueous solution, accompanied by mechanical stirring at a rate of 100 rpm, and filtering and drying after 60 minutes to obtain a modified wind turbine blade powder;

[0094] Among them, the mass ratio of wind turbine blade powder to silane coupling agent KH560 is 0.95:0.05;

[0095] (4) The modified wind turbine blade powder obtained in step (3) is used as the main raw material, and the raw materials including the following components are mixed evenly by weight to form a mixed base material:

[0096] 90 parts of modified wind turbine blade powder,

[0097] 10 parts of PMDI adhesive;

[0098] (5) pouring the mixed base material obtained in step (4) into a mold and preparing a recycled board by hot pressing;

[0099] The process parameters of the hot pressing molding are as follows: temperature 175°C, pressure 15 MPa, hot pressing for 15 min, and then demolding after cold pressing to obtain the recycled board.

[0100] 3. Test methods

[0101] The sample properties were tested according to ISO-178-2010.

[0102] Example 1

[0103] In Example 1, according to the steps of “2. Preparation method” above, a recycled board was finally prepared as a sample, which was recorded as WPMB90%-KH560.

[0104] The process flow is as follows Figure 1 As shown in the figure, after the waste wind turbine blades are cut and crushed, they are ground under mechanochemical action to obtain ultrafine powder. After the powder is modified with a silane coupling agent, it is blended with PMDI adhesive and hot-pressed to prepare recycled boards.

[0105] Comparative Example 1

[0106] Comparative Example 1 refers to the above-mentioned "2. Preparation method" steps, but in step (3), the silane coupling agent KH560 is replaced by the silane coupling agent KH550, and finally a recycled board is prepared as a comparative sample, which is recorded as WPMB90%-KH550.

[0107] Comparative Example 2

[0108] Comparative Example 2 refers to the above-mentioned "2. Preparation method" steps, but in step (3), the silane coupling agent KH560 is replaced by the silane coupling agent KH590, and finally a recycled board is prepared as a comparative sample, which is recorded as WPMB90%-KH590.

[0109] Comparative Example 3

[0110] Comparative Example 3 refers to the steps of “2. Preparation method” above, but in step (4), the PMDI adhesive is replaced with a water-based phenolic resin adhesive, and finally a recycled board is prepared as a comparative sample.

[0111] The mechanical properties of the recycled board finally prepared were tested as a comparison sample, and its bending strength was 16.58 MPa and the bending modulus was 1101 MPa.

[0112] Comparative Example 4

[0113] Comparative Example 4 refers to the steps of “2. Preparation method” above, but in step (4), the PMDI adhesive is replaced with an epoxy resin adhesive, and a recycled board is finally prepared as a comparative sample.

[0114] The mechanical properties of the recycled board finally prepared were tested as a comparison sample, and its bending strength was 38.34 MPa and the bending modulus was 2125 MPa.

[0115] Comparative Example 5

[0116] Comparative Example 5 refers to the above-mentioned "2. Preparation method" steps, but the wind turbine blade powder is not modified. That is, in step (4), the modified wind turbine blade powder is replaced by the wind turbine blade powder obtained in step (2), and finally a recycled board is prepared as a comparative sample, which is recorded as WPMB90%.

[0117] The test results are as follows Figures 2 to 7 As shown:

[0118] like Figure 2 As shown in (a), it can be seen that in the infrared spectrum of the modified wind turbine blade powder, the modified powder has a wavelength of 1100 cm -1 and 1025 cm -1Significant characteristic peaks appear at , corresponding to the symmetric and antisymmetric stretching vibrations of Si-O-Si bonds respectively; Figure 2 As shown in (b), the amount of residual carbon in the powder increases after modification. This is because there is a large amount of Si elements on the surface of the silane coupling agent, which remain on the surface of the glass fiber after high-temperature decomposition, proving that the silane coupling agent is successfully grafted to the surface of the wind turbine blade powder after modification.

[0119] like Figure 3 As shown, it can be seen that the average particle size of the powder before modification is 63.41 um, and the average particle size of the powder increases slightly after modification. The average particle size of WTB-KH550 is 63.94 um, the average particle size of WTB-KH560 is 63.89 um, and the average particle size of WTB-KH590 is 64.64 um.

[0120] like Figure 4 As shown, it can be seen that the strength of the samples of Comparative Example 1 and Comparative Example 2 both decreased, while Example 1 showed a unique modification effect by using a combination of silane coupling agent KH560 and PMDI adhesive, and its tensile strength and modulus were increased to 35.34 MPa and 5886 MPa, respectively.

[0121] like Figure 5 As shown, when Example 1 uses a combination of silane coupling agent KH560 and PMDI adhesive, compared with the unmodified comparative example 5 sample, the flexural strength and modulus do not deteriorate, and are increased to 56.49 MPa and 5557 MPa, respectively.

[0122] like Figure 6 As shown, the Rockwell hardness of the sample of Comparative Example 5 is 110.28 HRL, the hardness values of the samples of Comparative Example 1 and Comparative Example 2 are reduced to 106.10 HRL and 102.53 HRL respectively, and the hardness of the sample of Example 1 is increased to 112.99 HRL.

[0123] like Figure 7 As shown, the Soxhlet extract's gas chromatography-mass spectrometry allows the composition of the mobile small molecules in the material system to be determined. Clearly, in addition to bisphenol A, the extract is primarily composed of short-chain organic molecules such as ketones, alcohols, and esters. No toxic volatile organic compounds such as formaldehyde were found, preliminarily confirming that the sample in Example 1 meets the technical requirements for a formaldehyde-free, environmentally friendly material.

[0124] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing recycled boards from highly filled modified waste wind turbine blade powder, characterized in that The main steps include: (1) After pre-treatment including cleaning, the discarded wind turbine blade products are crushed into wind turbine blade fragments with an average particle size of no more than 8 mm; (2) adding the wind turbine blade fragments obtained in step (1) into a millstone-shaped solid phase force chemical reactor for grinding and pulverizing, and collecting the wind turbine blade powder after the grinding is completed; wherein, the process parameters of the millstone-shaped solid phase force chemical reactor are: grinding pressure of 5-10 MPa, introduction of -16-0 ° C circulating cooling liquid to control the temperature of the millstone surface, cyclic grinding for 1-2 times, and a millstone speed of 40-50 rpm; (3) Immersing the wind turbine blade powder obtained in step (2) in a 3-6% mass concentration of a silane coupling agent KH560 aqueous solution, accompanied by stirring, and filtering and drying after 30-60 minutes to obtain a modified wind turbine blade powder; (4) The modified wind turbine blade powder obtained in step (3) is used as the main raw material, and the raw materials including the following components are mixed evenly by weight to form a mixed base material: 80~90 parts of modified wind turbine blade powder, 10~20 parts of PMDI adhesive, Wherein, the modified wind turbine blade powder and PMDI adhesive total 100 parts; (5) Pour the mixed base material obtained in step (4) into a mold and prepare a recycled board by hot pressing.

2. The preparation method according to claim 1, wherein: The wind turbine blade powder in step (3) is immersed in a silane coupling agent KH560 aqueous solution with a mass concentration of 3-6%, and the mass ratio of the wind turbine blade powder to the silane coupling agent KH560 is (80-95): (5-20).

3. The preparation method according to claim 1, wherein: The recycled board is prepared by hot pressing in step (5), wherein the process parameters of the hot pressing are specifically: temperature 170-180 °C, pressure 12-15 MPa, and hot pressing 15-20 min.

4. The recycled board prepared by the method for preparing recycled board of highly filled modified waste wind turbine blade powder as claimed in claim 1.

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