Regenerated board highly filled with modified waste wind power blade powder and preparation method of regenerated board

Abstract

The invention belongs to the technical field of recycling of waste wind power blades and preparation of regenerated boards, and discloses a regenerated board highly filled with modified waste wind power blade powder and a preparation method of the regenerated board. The preparation method comprises the following steps: crushing a waste wind power blade product, and then adding the crushed waste wind power blade product into a millstone-shaped solid-phase mechanochemical reactor for grinding and crushing; the collected wind power blade powder is modified by selectively utilizing a silane coupling agent KH560, and a PMDI adhesive is matched and selectively used for blending a mold and pressing a plate. Under the condition of the specific combined treatment process, 90 wt% ultrahigh filling of the waste wind turbine blade powder can be achieved, the mechanical property of the prepared regenerated board is effectively improved, the regenerated board has good compactness, mechanical property and hardness, the performance greatly exceeds that of a traditional artificial board product, the technical requirements of formaldehyde-free environment-friendly materials are met, and the regenerated board is suitable for industrial production. And a new way is provided for large-scale recycling of the retired wind power blades.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling and reuse of waste wind turbine blades and preparation of recycled boards, and particularly relates to a recycled board made of highly filled and modified waste wind turbine blade powder and a preparation method thereof. In particular, it is directed to using a disk-shaped solid-phase force chemical reactor for industrial use disclosed in Chinese invention patent CN114534660B to treat waste wind turbine blades and using the treated blades as the main raw material for recycled boards. Background Art

[0002] The rapid development of social economy and the continuous growth of the world population have driven the strong demand for energy and fuels. The unsustainable consumption of fossil fuels (coal, oil, and natural gas) poses a major global energy challenge, and the development and deployment of new renewable energy sources have become the focus of global research. In recent years, renewable energy technologies such as wind energy, solar energy, and geothermal energy have developed rapidly. Among them, wind power has developed rapidly since 2000 due to its cleanliness, high efficiency, and sustainability, and wind power generation technology has also become one of the most mature power generation methods. However, a large number of retired wind turbine blades have become new solid wastes, which are difficult to recycle and reuse, attracting great attention from the whole society.

[0003] The core technical bottleneck in the recycling of wind turbine blades lies in the irreversible characteristics of the thermosetting resin therein. This is because epoxy resin is generally used as the matrix in the manufacture of wind turbine blades, and its curing cross-linking reaction forms a three-dimensional network structure, which has the following characteristics: 1) strong structural stability and excellent heat resistance; 2) the movement of molecular chain segments is blocked, and it is impossible to achieve reshaping through conventional hot processing methods; 3) the chemical bond dissociation energy is high, and conventional solvents are difficult to destroy. These characteristics lead to low added value of recycled products by traditional mechanical recycling methods, while chemical depolymerization faces technical and economic obstacles such as high energy consumption and expensive catalyst costs, seriously restricting its industrial application prospects.

[0004] The vast majority of wind turbine blade disposal methods at home and abroad are incineration or landfill disposal. Incineration produces a large amount of CO and CO2, polluting the atmosphere, and the performance of glass fibers recovered at high temperatures decreases and their value is low. China and some European countries have issued bans on incinerating retired blades. However, landfill treatment will affect arable land and cause groundwater problems, so landfill of wind turbine blades should be avoided as much as possible.

[0005] Theoretically, the best way to recycle retired wind turbine blades is to obtain recycled products with the same properties as the raw materials in a low-cost and environmentally friendly manner, including recovering fibers, fillers, and resins from waste wind turbine blades. Currently, the reported conventional recycling methods for waste wind turbine blades mainly include the following three: pyrolysis recycling, chemical (solvent decomposition) recycling, and physical (mechanical) recycling. Although pyrolysis recycling can achieve dual recycling of energy and materials, it is limited by technical and economic bottlenecks such as large investment in high-temperature reaction equipment and high operating energy consumption. In addition, glass fiber is commonly used as the reinforcing fiber in wind turbine blades, and its performance loss at high temperatures is more serious than that of carbon fiber. Therefore, its market promotion still faces challenges. The chemical recycling method has broad development prospects, but it is still in the experimental stage due to technical and high-cost limitations and needs continuous research and development. Physical recycling is more mature and has been commercialized in glass fiber composites. However, conventional physical recycling has problems such as large particle size and poor phase domain of particles, resulting in poor performance and low value of recycled products, making it difficult to be practically applied.

[0006] In recent years, some researchers have also tried a new idea of co-recycling using waste wind turbine blades as raw materials to prepare high-performance recycled products and achieved certain results. For example, the inventor of the present invention previously applied for a patent for invention "Glass fiber reinforced plastic recycled products using waste wind turbine blades as raw materials and their preparation methods" (CN118063854A), which discloses a glass fiber reinforced plastic recycled product using waste wind turbine blades as raw materials and its preparation method. First, it provides a method for preparing highly compatible and reactive fillers using waste wind turbine blades, which is to grind and crush waste wind turbine blade products in a disk-type solid-phase force chemical reactor after pretreatment to obtain ultra-fine powder of wind turbine blades, and then co-grind the ultra-fine powder of wind turbine blades with an activator to obtain highly compatible and reactive fillers; then use the highly compatible and reactive fillers as partial raw materials to prepare glass fiber reinforced plastic recycled products.

[0007] However, in the implementation and transformation evaluation of the above patent technology-related topics, it is still found that in order to prepare recycled products with good performance, due to the irreversible characteristics of thermosetting resins, the proportion of waste wind turbine blades in its raw materials has objective limitations, which seriously restricts the quantity and scale of waste wind turbine blades that can be recycled and processed during the implementation and transformation of this patent technology.

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

[0009] To solve the problems in the above-mentioned existing technologies, the present invention provides a recycled board made from highly filled and modified waste wind turbine blade powder and a preparation method thereof. The preparation method mills waste wind turbine blades into powder based on the solid-phase shear milling technology. On this basis, it is modified by using a silane coupling agent KH560 and co-molded into a board by blending with a PMDI adhesive. Under the above specific combined treatment process conditions, the present invention can achieve an ultra-high filling of 90 wt% of waste wind turbine blade powder, effectively improve the mechanical properties of the prepared recycled board, have good density, mechanical properties and hardness, with performance far exceeding that of traditional wood-based panel products, and meet the technical requirements of formaldehyde-free environmental protection materials, providing a new way for the large-scale recycling of retired wind turbine blades.

[0010] To achieve the above-mentioned purposes, the present invention is realized by a technical solution composed of the following technical measures.

[0011] The present invention provides a preparation method for a recycled board made from highly filled and modified waste wind turbine blade powder, mainly including the following steps:

[0012] (1) After pretreatment of waste wind turbine blade products including washing, they are processed and crushed into wind turbine blade scraps with an average particle size not higher than 8 mm.

[0013] (2) Add the wind turbine blade scraps obtained in step (1) into a disk-shaped solid-phase force chemical reactor for milling and crushing. After milling is completed, collect the wind turbine blade powder. Among them, the process parameters of the disk-shaped solid-phase force chemical reactor are: the milling pressure is 5 - 10 MPa, a circulating cooling liquid at -16 - 0 °C is introduced to control the temperature of the disk surface, circulate and mill 1 - 2 times, and the disk rotation speed is 40 - 50 revolutions per minute;

[0014] (3) Immerse the wind turbine blade powder obtained in step (2) in an aqueous solution of silane coupling agent KH560 with a mass concentration of 3 - 6%, and stir. After 30 - 60 minutes, filter and dry to obtain modified wind turbine blade powder;

[0015] (4) Use the modified wind turbine blade powder obtained in step (3) as the main raw material, and mix the following components of raw materials evenly by weight to obtain a mixed base material:

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

[0017] 10 - 20 parts of PMDI adhesive,

[0018] Among them, the total of the modified wind turbine blade powder and the PMDI adhesive is 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 described in step (1) includes washing, which mainly removes impurities on the surface of waste wind turbine blade products. If necessary, parts that are not wind turbine blades also need to be removed. Those skilled in the art can perform specific treatments according to the actual conditions of the waste wind turbine blade products they need to recycle and utilize, based on existing technologies.

[0021] In this article, the wind turbine blade fragments obtained by processing and crushing in step (1) to a uniform particle size not higher than 8 mm are sized to facilitate their placement in a disk-shaped solid-phase force chemical reactor for grinding. The processing and crushing method can adopt conventional crushing methods, such as being processed by existing conventional crushing equipment such as jaw crushers, planetary ball mills, and cryogenic ball mills.

[0022] In this article, the disk-shaped solid-phase force chemical reactor described in step (2) is the industrial disk-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 disk-shaped solid-phase force chemical reactor is an industrial equipment finally improved based on the principle of the force chemical reactor disclosed in the prior authorized patent ZL95111258.9. It is significantly different from the structure of the laboratory prototype machine when ZL95111258.9 was applied. A new disk structure was designed for industrial high-efficiency force chemical grinding treatment. The past vertically arranged disks were improved to be horizontally arranged, and the disk size was significantly increased. Based on the horizontally arranged and large-sized disks, relevant fixed disk components and a hydraulic lifting system were innovatively designed, greatly improving its three-dimensional shear force.

[0024] Generally, the actual operation of the above-mentioned cyclic grinding process is to place the material in a disk-shaped solid-phase force chemical reactor for grinding, collect the product at the discharge end, and then place it in the disk-shaped solid-phase force chemical reactor for grinding again. The above process is regarded as 1 cycle of cyclic grinding.

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

[0026] The technical object of the present invention is how to recycle waste wind turbine blades with high value and on a large scale. Based on this technical object, the technical solution of the present invention is based on the prior invention patent "Fiberglass Reinforced Plastic Recycled Products Using Waste Wind Turbine Blades as Raw Materials and Their Preparation Methods" (CN118063854A), and focuses on how to use waste wind turbine blade powder as the main raw material in recycled products.

[0027] In the process of technological exploration, the inventors found that under the ultra-fine particle size condition of the powder after milling based on the solid-phase shear milling technology, by hot pressing and forming a board through blending with adhesives commonly used in wood-based panels, the waste wind turbine blade powder is coated with the adhesive to achieve the preparation of a recyclable board with processability.

[0028] However, even on the premise of adding a sufficient amount of adhesive to meet its processability, there are still certain limitations in the mechanical properties of the prepared recycled board, which is also the main reason for the generally low filling amount in the past preparation of recycled products using waste wind turbine blades.

[0029] To solve the above problems, based on the characteristic that wind turbine blades mainly use epoxy resin as the matrix, the inventors tried to modify with different silane coupling agents, and designed a series of orthogonal tests by blending the modified wind turbine blade powder with different adhesives for hot pressing and forming a board.

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

[0031] According to conventional thinking, although wind turbine blades mainly use epoxy resin as the matrix, because the epoxy resin in waste wind turbine blades has been crosslinked and cured, it is generally considered that the modification effect of using silane coupling agent KH550 is better, and when using silane coupling agent KH550, the amino group (-NH2) on the surface of the modified powder can directly react with the -NCO group in the subsequent PMDI adhesive to form a strong and tough urea bond (-NH-CO-NH-), and the reaction rate of this reaction is fast and the bond energy is high. In comparison, the hydroxyl group (-OH) formed after the epoxy group modification of silane coupling agent KH560 forms a urethane bond (-NH-CO-O-) with the -NCO group, and the reactivity of this reaction is lower than the direct reaction of the amino group, and the bond energy is also lower. In the selection of adhesives, generally speaking, silane coupling agent KH560 and epoxy resin adhesive can be used as a preferred combination according to their reaction principles.

[0032] However, based on the experimental results, the inventors were surprised to find that by selecting the modification with silane coupling agent KH560 and blending and molding with PMDI adhesive, the properties such as the strength and modulus of the prepared recycled board were significantly improved, and were significantly better than other comparison test groups, and the comprehensive performance was much higher than the industry standard, achieving unexpected experimental results.

[0033] In addition, when choosing to modify with silane coupling agent KH560 and blending and hot-pressing with PMDI adhesive to prepare the recycled board, a very significant improvement in the hardness of the obtained recycled board has occurred.

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

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

[0036] In this article, the mixed base material in step (5) is poured into a mold and prepared into a recycled board by hot pressing. The process steps / conditions / parameters of hot pressing can all refer to the conventional preparation process of wood-based panels in the prior art.

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

[0038] In this article, the filtration, drying, and mixing all follow the conventional principles in chemical engineering, 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 preparation method thereof. This method first realizes the ultra-fine pulverization of waste wind turbine blades through the strong three-dimensional shear force of a disk-shaped solid-phase force chemical reactor, then modifies the wind turbine blade powder with silane coupling agent KH560, and blends and hot-presses with PMDI adhesive. Under the above specific combined treatment process conditions, the present invention can achieve a 90wt% ultra-high filling of waste wind turbine blade powder, effectively improve the mechanical properties of the prepared recycled board, and has good density, mechanical properties, and hardness, and the performance far exceeds that of traditional wood-based panel 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, different from traditional physical bonding, the hydroxyl functional groups on the surface of the modified wind turbine blade powder react with the isocyanate groups in the PMDI adhesive, greatly improving the mechanical properties of the wood-based panel.

[0042] (3) The technical solution of the present invention uses waste wind turbine blades as the main raw material and can achieve high-fill recycling, which is different from the methods with too low recovery rates in the existing recycling technologies, and can recycle waste wind turbine blades more efficiently, with a recycling amount as high as 90 wt%.

[0043] (4) The technical solution of the present invention is not only easy to operate, has low recycling costs, is easy to scale up production, but also produces no waste and no secondary pollution during the recycling process. The finally formed recycled board has excellent mechanical properties and can be used as a substitute product of the same kind, with a clear industrialization prospect. Description of the Drawings

[0044] Figure 1 It is a process flow schematic diagram of the preparation method of Example 1 of the present invention.

[0045] Figure 2 It is an infrared spectrum diagram (a) and a thermogravimetric comparison diagram (b) of the wind turbine blade powder obtained in step (2) and the modified wind turbine blade powder obtained in step (3) in Example 1, Comparative Example 1-2 of the present invention. Among them, WTB refers to the wind turbine blade powder obtained in step (2), and WTB-KH550, WTB-KH560, and WTB-KH590 respectively correspond to the modified wind turbine blade powder obtained in step (3) in Comparative Example 1, Example 1, and Comparative Example 2.

[0046] Figure 3 It is a particle size comparison diagram of the wind turbine blade powder obtained in step (2) and the modified wind turbine blade powder obtained in step (3) in Example 1, Comparative Example 1-2 of the present invention. Among them, Figure (a) is the particle size distribution diagram of the wind turbine blade powder obtained in step (2) in Example 1, Comparative Example 1-2, Figure (b) is the particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) in Comparative Example 1, Figure (c) is the particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) in Example 1, and Figure (d) is the particle size distribution diagram of the modified wind turbine blade powder obtained in step (3) in Comparative Example 2.

[0047] Figure 4 It is a tensile strength comparison diagram of the recycled boards prepared in Example 1, Comparative Example 1-2 and Comparative Example 5 of the present invention. Among them, Figure (a) is the stress-strain curve of the recycled boards prepared in Example 1, Comparative Example 1-2 and Comparative Example 5, and Figure (b) is the tensile strength and modulus of the recycled boards prepared in Example 1, Comparative Example 1-2 and Comparative Example 5. Pure corresponds to the sample of Comparative Example 5.

[0048] Figure 5It is a comparison chart of the flexural strength of the recycled boards prepared in Example 1, Comparative Examples 1-2 and Comparative Example 5 of the present invention. Among them, Figure (a) is the stress-strain curve of the recycled boards prepared in Example 1, Comparative Examples 1-2 and Comparative Example 5, and Figure (b) is 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 of Comparative Example 5.

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

[0050] Figure 7 It is the gas chromatography-mass spectrometry chart of the Soxhlet extract of the recycled board prepared in Example 1 of the present invention. Detailed implementation manners

[0051] To further understand the present invention, the preferred implementation manners of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only used to further illustrate the features and advantages of the present invention, rather than limiting the claims of the invention. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all regarded as included in the present invention. The methods and applications of the present invention have been described through preferred examples, and those related can obviously make changes or appropriate changes and combinations to the methods and applications described in this article 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 are fully aware of 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 board of highly filled modified waste wind turbine blade powder, which mainly includes the following steps:

[0053] (1) After the waste wind turbine blade products are pretreated including washing, they are processed and crushed into wind turbine blade fragments with an average particle size not higher than 8 mm;

[0054] (2) The wind turbine blade fragments obtained in step (1) are added to a disk-shaped solid-phase force chemical reactor for grinding and crushing. After the grinding is completed, the wind turbine blade powder is collected; among them, the process parameters of the disk-shaped solid-phase force chemical reactor are: the grinding pressure is 5-10 MPa, circulating cooling liquid at -16 to 0 °C is introduced to control the temperature of the disk surface of the grinding disk, circulating grinding is carried out 1-2 times, and the rotation speed of the grinding disk is 40-50 revolutions per minute;

[0055] (3) Immerse the wind turbine blade powder obtained in step (2) in an aqueous solution of silane coupling agent KH560 with a mass concentration of 3-6%, and stir. After 30-60 minutes, filter and dry to obtain modified wind turbine blade powder;

[0056] (4) Take the modified wind turbine blade powder obtained in step (3) as the main raw material. By weight, mix the following components evenly as the mixed base material:

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

[0058] 10-20 parts of PMDI adhesive,

[0059] Among them, the total of the modified wind turbine blade powder and PMDI adhesive is 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 pre-treatment including washing in step (1) mainly removes the surface impurities of the waste wind turbine blade products. If necessary, the non-wind turbine blade parts also need to be removed. Those skilled in the art can perform specific treatments according to the actual conditions of the waste wind turbine blade products they need to recycle and utilize, according to the existing technology.

[0062] In this article, the wind turbine blade fragments processed in step (1) to a uniform particle size not higher than 8 mm are sized to facilitate their placement in the disk-shaped solid-phase force chemical reactor for grinding. The processing and grinding method can adopt a conventional grinding method. In one implementation, for example, it is processed by existing conventional grinding equipment such as a jaw crusher, a planetary ball mill, a cryogenic ball mill, etc.

[0063] In this article, the disk-shaped solid-phase force chemical reactor in step (2) is the industrial disk-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 disk-shaped solid-phase force chemical reactor is an industrial equipment finally improved based on the principle of the force chemical reactor disclosed in the prior authorized patent ZL95111258.9. It is significantly different from the structure of the laboratory prototype machine at the time of the application of ZL95111258.9. A new disk structure is designed for industrial high-efficiency force chemical grinding treatment. The disk is changed from a vertical setting in the past to a horizontal setting, and the disk size is greatly increased. Based on the horizontally set and large-sized disk, relevant fixed disk components and a hydraulic lifting system are innovatively designed, greatly improving its three-dimensional shear force.

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

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

[0067] The technical objective of the present invention is how to recycle waste wind turbine blades with high value and on a large scale. Based on this technical objective, the technical solution of the present invention is based on the prior invention patent "Fiberglass Reinforced Plastic Recycled Products Using Waste Wind Turbine Blades as Raw Materials and Their Preparation Methods" (CN118063854A), and focuses on how to use the waste wind turbine blade powder as the main raw material in the recycled products.

[0068] During the technical exploration process, the inventors found that under the ultra-fine particle size conditions of the powder milled based on the solid-phase shear milling technology, through hot pressing and forming into boards by blending with adhesives commonly used in wood-based panels, the waste wind turbine blade powder is coated with the adhesive to realize the preparation of recyclable boards.

[0069] However, even on the premise of adding a sufficient amount of adhesive to meet its processability, the mechanical properties of the prepared recycled boards still have certain limitations, which is also the main reason for the generally low filling amount in the past when using waste wind turbine blades to prepare recycled products.

[0070] To solve the above problems, based on the characteristic that wind turbine blades mainly use epoxy resin as the matrix, the inventors tried to modify with different silane coupling agents, and designed a series of orthogonal tests by blending the modified wind turbine blade powder with different adhesives for hot pressing and forming into boards.

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

[0072] According to conventional thinking, although epoxy resin is mainly used as the matrix for wind turbine blades, since the epoxy resin in waste wind turbine blades has been crosslinked and cured, it is generally considered that the modification effect is better when using silane coupling agent KH550. And when using silane coupling agent KH550, the amino group (-NH2) on the surface of the modified powder can directly react with the -NCO group in the subsequent PMDI adhesive to form strong and tough urea bonds (-NH-CO-NH-), and this reaction has a fast rate and high bond energy. In contrast, the hydroxyl group (-OH) formed after the epoxy group modification of silane coupling agent KH560 forms a urethane bond (-NH-CO-O-) with the -NCO group. The reactivity of this reaction is lower than the direct reaction of the amino group, and the bond energy is also lower. Regarding the choice of adhesives, generally, silane coupling agent KH560 and epoxy resin adhesives can be preferably paired according to their reaction principles.

[0073] However, based on the test results, the inventors surprisingly found that by selecting to use silane coupling agent KH560 for modification and pairing it with PMDI adhesive for blending and compression molding to prepare the recycled board, the properties such as strength and modulus of the obtained recycled board have been significantly improved, and are significantly better than other comparative test groups. The comprehensive performance is much higher than the industry standard, achieving unexpected test results.

[0074] In addition, when selecting to use silane coupling agent KH560 for modification and pairing it with PMDI adhesive for blending and compression molding to prepare the recycled board, a very significant improvement in the hardness of the obtained recycled board has occurred.

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

[0076] In one of the embodiments, the mass concentration of the aqueous solution of silane coupling agent KH560 in step (3) is 3 - 6%, such as 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6% or any range or point value between them.

[0077] In one of the embodiments, in order to make the modification more sufficient, the wind turbine blade powder in step (3) is immersed in an aqueous solution of silane coupling agent KH560 with a mass concentration of 3 - 6%. The feeding ratio of the wind turbine blade powder to silane coupling agent KH560 is preferably (80 - 95):(5 - 20), such as 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 between them.

[0078] In this text, the mixed base material described in step (5) is poured into a mold and prepared into a recycled board by hot pressing. The process steps / conditions / parameters of hot pressing can all refer to the conventional preparation process of wood-based panels in the prior art.

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

[0080] In this text, the filtration, drying, and mixing all follow the conventional principles in chemical engineering processes, and those skilled in the art can perform specific operations according to common knowledge.

[0081] The following will further explain the present application with reference to the embodiments. However, those skilled in the art should understand that these embodiments are provided only for the purpose of illustration and are not intended to limit the present application.

[0082] Embodiment

[0083] The following will describe the implementation scheme of the present application in detail in combination with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. The present application should not be construed as being limited by the specific embodiments described.

[0084] 1. Raw materials

[0085] The waste (retired) wind turbine blades are the 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%), 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 Kemit Technology Co., Ltd.;

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

[0090] 2. Preparation method

[0091] (1) After the waste wind turbine blade products are pretreated including washing, they are processed and crushed into wind turbine blade fragments with an average particle size of 6 mm.

[0092] (2) The wind turbine blade fragments obtained in step (1) are added to a disk-shaped solid-phase force chemical reactor for grinding and crushing. After the grinding is completed, wind turbine blade powder is collected. Among them, the process parameters of the disk-shaped solid-phase force chemical reactor are: the grinding pressure is 5 MPa, circulating cooling liquid at -15 °C is introduced to control the temperature of the disk surface, circulating grinding is carried out once, and the disk rotation speed is 50 revolutions per minute.

[0093] (3) The wind turbine blade powder obtained in step (2) is immersed in an aqueous solution of silane coupling agent KH560 with a mass concentration of 3%, and mechanical stirring is carried out at a rate of 100 rpm. After 60 min, it is filtered by suction and dried to obtain modified wind turbine blade powder.

[0094] Among them, the mass ratio of the wind turbine blade powder to the 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. By weight, the following components of raw materials are mixed evenly to obtain a mixed base material:

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

[0097] 10 parts of PMDI adhesive;

[0098] (5) The mixed base material obtained in step (4) is poured into a mold and prepared into a recycled board by hot pressing.

[0099] Among them, the process parameters of the hot pressing are specifically: temperature 175 °C, pressure 15 MPa, hot pressing for 15 min, and then cold pressing and demolding to obtain a recycled board.

[0100] 3. Test method

[0101] The sample performance is tested according to ISO-178-2010.

[0102] Example 1

[0103] Example 1 is to finally prepare a recycled board as a sample according to the steps of the above "2. Preparation method", denoted as WPMB90%-KH560.

[0104] Its process flow is as Figure 1 shown. In the figure, the waste wind turbine blade is cut and crushed, ground under the action of mechanochemistry to obtain ultrafine powder. After the powder is modified by silane coupling agent, it is blended with PMDI adhesive and prepared into a recycled board by hot pressing.

[0105] Comparative Example 1

[0106] Comparative Example 1 referred to the steps of the above-mentioned "2. Preparation Method", but in step (3), the silane coupling agent KH560 was replaced with the silane coupling agent KH550, and finally a regenerated board was prepared as a comparative sample, denoted as WPMB90%-KH550.

[0107] Comparative Example 2

[0108] Comparative Example 2 referred to the steps of the above-mentioned "2. Preparation Method", but in step (3), the silane coupling agent KH560 was replaced with the silane coupling agent KH590, and finally a regenerated board was prepared as a comparative sample, denoted as WPMB90%-KH590.

[0109] Comparative Example 3

[0110] Comparative Example 3 referred to the steps of the above-mentioned "2. Preparation Method", but in step (4), the PMDI adhesive was replaced with an aqueous phenolic resin adhesive, and finally a regenerated board was prepared as a comparative sample.

[0111] The regenerated board finally prepared was used as a comparative sample for mechanical property testing. Its flexural strength was 16.58 MPa and its flexural modulus was 1101 MPa.

[0112] Comparative Example 4

[0113] Comparative Example 4 referred to the steps of the above-mentioned "2. Preparation Method", but in step (4), the PMDI adhesive was replaced with an epoxy resin adhesive, and finally a regenerated board was prepared as a comparative sample.

[0114] The regenerated board finally prepared was used as a comparative sample for mechanical property testing. Its flexural strength was 38.34 MPa and its flexural modulus was 2125 MPa.

[0115] Comparative Example 5

[0116] Comparative Example 5 referred to the steps of the above-mentioned "2. Preparation Method", but the wind power blade powder was not modified, that is, in step (4), the modified wind power blade powder was replaced with the wind power blade powder obtained in step (2), and finally a regenerated board was prepared as a comparative sample, denoted as WPMB90%.

[0117] The test results are as Figures 2 - 7 shown:

[0118] As Figure 2 shown in (a), it can be seen that in the infrared spectrum of the modified wind power blade powder, after modification, the powder has absorption peaks at 1100 cm -1 and 1025 cm -1Significant characteristic peaks appear, corresponding to the symmetric and antisymmetric stretching vibrations of the Si-O-Si bond respectively; as Figure 2 As shown in (b), the char residue of the modified powder increases. This is because there are a large number 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 has been successfully grafted onto the surface of the wind turbine blade powder after modification.

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

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

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

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

[0123] As Figure 7 shown, through the gas chromatography-mass spectrometry of the Soxhlet extract, the composition of the migratory small molecules in the material system can be determined. It is obvious that in addition to bisphenol A, the extract is mainly composed of short-chain organic molecules such as ketones, alcohols and esters, and no toxic volatile organic compounds such as formaldehyde are found. It is preliminarily confirmed that the sample in Example 1 meets the technical requirements of the formaldehyde-free environmental protection material.

[0124] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a regenerated board from a high-fill modified waste wind power blade powder, characterized in that It mainly includes the following steps: (1) After the waste wind power blade products are pretreated including washing, they are processed and crushed into wind power blade fragments with an average particle size not higher than 8 mm; (2) The wind power blade fragments obtained in step (1) are added into a disk-shaped solid-phase force chemical reactor for grinding and crushing. After the grinding is completed, the wind power blade powder is collected. Among them, the process parameters of the disk-shaped solid-phase force chemical reactor are: the grinding pressure is 5 - 10 MPa, a circulating cooling liquid at -16 - 0 °C is introduced to control the temperature of the disk surface of the grinding disk, the circulating grinding is carried out 1 - 2 times, and the rotational speed of the grinding disk is 40 - 50 revolutions per minute; (3) The wind power blade powder obtained in step (2) is impregnated in an aqueous solution of silane coupling agent KH560 with a mass concentration of 3 - 6%, and accompanied by stirring. After 30 - 60 min, it is filtered and dried to obtain modified wind power blade powder; (4) The modified wind power blade powder obtained in step (3) is used as the main raw material. By weight, the raw materials including the following components are mixed evenly to be used as a mixed base material: 80 - 90 parts of modified wind power blade powder, 10 - 20 parts of PMDI adhesive, Among them, the total of the modified wind power blade powder and PMDI adhesive is 100 parts; (5) The mixed base material obtained in step (4) is poured into a mold and prepared into a recycled board by hot pressing.

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

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

4. A recycled board prepared by the method for preparing a recycled board of highly filled modified waste wind power blade powder as described in claim 1.

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