Wood-plastic composite material for recycling waste photovoltaic module and preparation method of wood-plastic composite material

Abstract

The invention relates to a wood-plastic composite material for recycling a waste photovoltaic module. The wood-plastic composite material comprises the following components in parts by weight: 25-65 parts of photovoltaic silicon powder; 10-30 parts by weight of thermoplastic plastic; 10-45 parts by weight of wood fiber powder; 5-10 parts by weight of a compatilizer; 2-5 parts by weight of a coupling agent; the photovoltaic silicon powder is prepared from, by weight, 1-3 parts of stearic acid and 1-3 parts of optional pigment, and the photovoltaic silicon powder is obtained by recycling waste photovoltaic modules. The wood-plastic composite material has high mechanical strength, good corrosion resistance and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy solid waste resource recovery, and particularly relates to a wood-plastic composite material for recycling waste photovoltaic components and a preparation method thereof. Background Art

[0002] Against the backdrop of global energy transition and environmental protection, the photovoltaic industry, as a clean, renewable energy technology, has experienced rapid growth. As photovoltaic modules reach the end of their service life, the efficient recovery and reuse of silicon powder has become a critical issue. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems faced in the prior art by applying photovoltaic silicon in photovoltaic modules to wood-plastic composite materials, thereby providing a wood-plastic composite material with greatly improved performance.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions:

[0005] According to a first aspect of the present invention, a wood-plastic composite material for recycling waste photovoltaic modules is provided, wherein the wood-plastic composite material comprises the following components:

[0006] 25-65 parts by weight of photovoltaic silicon powder, preferably with a particle size of 60 to 200 mesh;

[0007] 10-30 parts by weight of thermoplastic;

[0008] 10-45 parts by weight of wood fiber powder;

[0009] 5-10 parts by weight of compatibilizer;

[0010] 2-5 parts by weight of coupling agent;

[0011] 1-3 parts by weight of stearic acid, and

[0012] 1-3 parts by weight of optional pigment,

[0013] The photovoltaic silicon powder is obtained by recycling waste photovoltaic modules.

[0014] In the wood-plastic composite material of the present application, pigments may be added or not added according to actual applications, that is, pigments are optional.

[0015] Preferably, the recycling process comprises:

[0016] (1) crushing and sorting, wherein the waste photovoltaic modules are physically crushed to obtain coarse silicon powder after sorting;

[0017] (2) Aluminum removal: removing aluminum by soaking in alkaline solution;

[0018] (3) Silver extraction: removing silver by soaking in acid;

[0019] (4) Remove the passivation layer by soaking in hydrofluoric acid;

[0020] (5) Filter and dry.

[0021] Preferably, the photovoltaic silicon powder includes a first photovoltaic silicon powder having a particle size of 60-100 mesh, preferably 60-80 mesh, and a second photovoltaic silicon powder having a particle size greater than 100 mesh and less than 200 mesh, preferably 130-180 mesh; wherein the first photovoltaic silicon powder and the second photovoltaic silicon powder are added in a weight ratio of 1:1 to 1:2.

[0022] Preferably, the weight content of the photovoltaic silicon powder in the wood-plastic composite material is greater than 25% and less than 70%, preferably greater than 30% and less than 60%.

[0023] The wood fiber powder of the present invention is not particularly limited. For example, fiber powder for wood-plastic composite materials known in the art or corresponding commercial wood fiber powder can be used.

[0024] Preferably, the thermoplastic is one or more selected from polyethylene, polypropylene and polyvinyl chloride.

[0025] Preferably, the wood fiber powder is a combination of one or more selected from wood powder, bamboo powder, crop straw powder and rice husk powder.

[0026] Preferably, the compatibilizer is one or more selected from maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, and maleic anhydride grafted polystyrene, more preferably one or more selected from maleic anhydride grafted polypropylene and maleic anhydride grafted polyethylene.

[0027] Preferably, the coupling agent is one or more selected from silane coupling agents, titanate coupling agents, and maleic anhydride grafted polyolefins, more preferably silane coupling agents.

[0028] According to a second aspect of the present invention, there is provided a method for preparing a wood-plastic composite material for recycling waste photovoltaic modules, the method comprising the following steps:

[0029] (1) Recycling waste photovoltaic modules to obtain photovoltaic silicon powder;

[0030] (2) Grinding the photovoltaic silicon powder and screening it for later use; preferably, the photovoltaic silicon powder is ground to a particle size of ≤30 mesh, and sieving to obtain silicon powder particles of 60-200 mesh for later use.

[0031] (3) 25-65 parts by weight of photovoltaic silicon powder, 10-30 parts by weight of thermoplastic plastic, 10-45 parts by weight of wood fiber powder, 5-10 parts by weight of compatibilizer, 2-5 parts by weight of coupling agent, 1-3 parts by weight of stearic acid, optional pigment and 5-10 parts by weight of water are mixed uniformly, and then injection molding or extrusion molding is performed to obtain the wood-plastic composite material.

[0032] In the present application, the addition of water can improve the fluidity of the mixture after stirring, and in the subsequent injection molding process, the water is basically completely volatilized, and the moisture content in the resulting wood-plastic composite material can be ignored. Here, the water is preferably deionized water.

[0033] Preferably, the recycling process includes crushing and sorting, aluminum removal, silver extraction, and passivation layer removal, followed by filtration and drying, wherein:

[0034] The aluminum removal comprises soaking in 1-2 mol / L sodium hydroxide solution for 1-2 hours; and / or

[0035] The silver extraction comprises soaking in a 1-3 mol / L nitric acid solution for 40-50 minutes to remove silver; and / or

[0036] The passivation layer removal comprises soaking in 8% v / v hydrofluoric acid for 20-40 minutes; and / or

[0037] The drying comprises drying at 60° C. to 90° C. for 120 to 180 minutes after rinsing.

[0038] The recycling process can also be carried out using any other method known in the art. Waste photovoltaic modules are typically acid-washed or acid-treated during recycling. This acid treatment removes impurities from the silicon powder surface of the waste photovoltaic modules, exposing a purer silicon surface. The silicon surface may also be etched, creating more pores or microstructures, increasing the surface area. A larger surface area means more contact points, which can enhance interactions with other materials (such as compatibilizers), thereby facilitating dispersion. Furthermore, acid treatment may introduce surface functional groups (such as hydroxyl groups), which promote reaction with the compatibilizer and form a stronger interfacial bond.

[0039] Preferably, the step (3) specifically comprises: a) taking a first photovoltaic silicon powder, a thermoplastic plastic, and a wood fiber, heating and mixing them respectively to form a primary injection molding compound; b) subsequently adding a second photovoltaic silicon powder, a compatibilizer, a coupling agent, stearic acid, an optional pigment, and water for secondary mixing to form a secondary injection molding compound; mixing the secondary injection molding compound; extruding or injection molding the compound; and cutting the extruded or injection molded plate to obtain the wood-plastic composite material.

[0040] Preferably, the particle size of the first photovoltaic silicon powder is 60-100 mesh, preferably 60-80 mesh; the particle size of the second photovoltaic silicon powder is greater than 100 mesh and less than 200 mesh, preferably 130-180 mesh. Wherein, the weight ratio of the first photovoltaic silicon powder and the second photovoltaic silicon powder is 1:1 to 1:2, for example, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, preferably 1:1.3 to 1:1.7, most preferably 1:1.5. The present invention uses the synergistic effect of multi-scale particles and the combination of particles of different particle sizes to more effectively fill gaps of different sizes, thereby reducing the overall void ratio. For example, large particles fill large gaps, and small particles fill the remaining small gaps to form a compact structure.

[0041] Preferably, the thermoplastic is selected from one or more of polyethylene, polypropylene and polyvinyl chloride.

[0042] Preferably, the wood fiber powder is a combination of one or more selected from wood powder, bamboo powder, crop straw powder and rice husk powder.

[0043] Preferably, the compatibilizer is one or more selected from maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, and maleic anhydride grafted polystyrene, more preferably one or more selected from maleic anhydride grafted polypropylene and maleic anhydride grafted polyethylene.

[0044] Preferably, the coupling agent is one or more selected from silane coupling agents, titanate coupling agents, and maleic anhydride grafted polyolefins, more preferably a silane coupling agent.

[0045] Preferably, in step (3), the plasticizing temperature is 170-220° C., preferably 190-210° C.; the mold temperature is 130-190° C., preferably 160-180° C.; and the pressure is 0.1-0.7 MPa, preferably 0.5-0.6 MPa.

[0046] Preferably, in step (3), the primary mixture is cut into blocks of 1-3 cm in size after the initial mixing, and then a secondary mixing is performed.

[0047] Beneficial effects:

[0048] The use of silicon powder recovered from discarded photovoltaic modules in wood-plastic composites has the following advantages:

[0049] (1) Efficient resource recycling: By recycling silicon powder from waste photovoltaic modules and using it to produce wood-plastic composite materials, the waste is transformed into high-value products, greatly improving resource utilization efficiency. This recycling model reduces the demand for new raw materials and reduces the environmental impact of the production process.

[0050] (2) Environmentally friendly material: Due to its good physical properties, such as high hardness and strong wear resistance, silica fume as a reinforcing material for wood-plastic composites not only improves the physical properties of the product, such as strength and wear resistance, but also reduces environmental pollution due to its non-organic properties. Compared with traditional wood, wood-plastic composites are more durable and require less maintenance and replacement, thereby reducing the overall environmental footprint.

[0051] (3) Significant economic benefits: Using waste silicon powder to produce wood-plastic composite materials can significantly reduce the cost of raw materials. At the same time, since the addition of silicon powder improves the performance of the product, it can open up a wider range of application areas.

[0052] (4) Compared with traditional inorganic fillers, photovoltaic silicon powder achieves high-strength and high-durability wood-plastic composite materials by optimizing pore structure and improving interface bonding strength, while also having resource recycling and cost advantages.

[0053] The method first uses silicon powder recovered from discarded photovoltaic modules as an important filler and mixes it into wood-plastic composite products. Due to the high strength and corrosion resistance of silicon powder, the use strength and corrosion resistance of wood-plastic composite products can be greatly improved. By controlling the amount of photovoltaic silicon powder added, the performance of the wood-plastic composite products is improved and the resource utilization of silicon powder is also achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is an SEM image of the photovoltaic silicon powder after grinding the silicon material recovered in Example 1 of the present invention. DETAILED DESCRIPTION

[0055] In order to make the technical means, innovative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below.

[0056] The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments and scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in this application specification, including technical solutions that adopt any obvious substitutions and modifications to the embodiments described herein.

[0057] The present invention will be further described below through specific examples. The examples of the present invention are only for illustration of the present invention and do not mean that the scope of the present invention is limited thereto.

[0058] Material

[0059] PE: PE80, Zhongyue;

[0060] Compatibilizer: maleic anhydride grafted polypropylene, ADDIMER 630R, CERONAS, viscosity: 40 mPa·s (120°C);

[0061] Silane coupling agent: DOWSIL OFS-6020, DOW, viscosity: 5mm 2 / S;

[0062] Stearic acid: stearic acid 1801, Ricoh, melting point: 67-72°C;

[0063] Pigments: carbon black, de blue;

[0064] Wood powder: Pearl bamboo, ash content is 5%, moisture content is 7%.

[0065] Example

[0066] Example 1

[0067] A wood-plastic composite material is prepared from the following raw materials: 15 parts by weight of wood flour; 15 parts by weight of PE; 55 parts by weight of photovoltaic silicon powder; 5 parts by weight of a compatibilizer; 3 parts by weight of a coupling agent; 1 part by weight of stearic acid; 1 part by weight of carbon black; and 5 parts by weight of deionized water.

[0068] The specific process is as follows: waste photovoltaic modules are physically crushed and sorted to obtain photovoltaic cell powder. Then, the powder is soaked in 1.5 mol / L sodium hydroxide solution for 1.5 hours to remove aluminum, soaked in 2 mol / L nitric acid solution for 50 minutes to remove silver, and then soaked in low concentration 8% v / v hydrofluoric acid for 30 minutes to remove the passivation layer. After rinsing, the powder is dried at 80°C to obtain recycled silicon material. The recycled silicon material is mechanically ground into powder. The silicon powder particles are as follows: Figure 1 The process is shown in Figure 1. Multi-stage screening is then performed to select 60-200 mesh photovoltaic silicon powder particles for later use. The photovoltaic silicon powder is further screened to obtain a first photovoltaic silicon powder with a mesh size of 60-100 and a second photovoltaic silicon powder with a mesh size between 100 and 200. The screened first photovoltaic silicon powder with a mesh size of 60-100 is heated and mixed with wood flour and PE to form a primary injection molding compound, which is then cut into 2 cm blocks. A second mixing step is then performed to add the second photovoltaic silicon powder with a mesh size between 100 and 200, a compatibilizer, a coupling agent, stearic acid, carbon black, and deionized water. The mixture is then mixed thoroughly in a mixer for a period of time. The first photovoltaic silicon powder and the second photovoltaic silicon powder are added in a weight ratio of 1:1.5. The mixture is then extruded at a plasticizing temperature of 200°C, a mold temperature of 170°C, and a pressure of 0.6 MPa. The sheets are then cut to obtain the newly produced wood-plastic composite material.

[0069] Example 2

[0070] A wood-plastic composite material is prepared from the following raw materials: 15 parts by weight of wood flour; 25 parts by weight of PE; 45 parts by weight of photovoltaic silicon powder; 5 parts by weight of a compatibilizer; 3 parts by weight of a coupling agent; 1 part by weight of stearic acid; 1 part by weight of carbon black; and 5 parts by weight of deionized water.

[0071] The specific process is the same as that of Example 1, wherein the particle size of the first photovoltaic silicon powder is 60-100 mesh, and the particle size of the second photovoltaic silicon powder is greater than 100 and less than 200 mesh, and they are added at a weight ratio of 1:1.5.

[0072] Comparative Example 1

[0073] The only difference from Example 2 is that no photovoltaic silicon powder is added.

[0074] Example 3

[0075] A wood-plastic composite material is prepared from the following raw materials: 30 parts by weight of wood flour, 25 parts by weight of PE, 25 parts by weight of photovoltaic silicon powder, 8 parts by weight of a compatibilizer, 3 parts by weight of a coupling agent, 2 parts by weight of stearic acid, 1 part by weight of carbon black, and 5 parts by weight of deionized water.

[0076] The specific process is the same as that of Example 1, wherein the first photovoltaic silicon powder is 60-80 mesh, the second photovoltaic silicon powder is 130-180 mesh, and they are added in a weight ratio of 1:1.5.

[0077] When the content of photovoltaic silicon powder is low, the mechanical properties of the obtained wood-plastic composite material are limitedly improved and the density is low, indicating that insufficient filling leads to loose bonding of the matrix and the reinforcing effect of photovoltaic silicon powder cannot be fully exerted.

[0078] Comparative Example 2

[0079] The only difference from Example 3 is that no photovoltaic silicon powder is added.

[0080] Example 4

[0081] A wood-plastic composite material is prepared from the following raw materials: 10 parts by weight of wood flour, 10 parts by weight of PE, 65 parts by weight of photovoltaic silicon powder, 5 parts by weight of a compatibilizer, 5 parts by weight of a coupling agent, 3 parts by weight of stearic acid, 1 part by weight of carbon black, and 5 parts by weight of deionized water.

[0082] The specific process is the same as that of Example 1, wherein the first photovoltaic silicon powder is 60-80 mesh, the second photovoltaic silicon powder is 130-180 mesh, and they are added in a weight ratio of 1:1.5.

[0083] The resulting wood-plastic composite has processing problems, with fluidity decreasing during injection molding, microcracks appearing on the surface after molding, and the brittleness of the material significantly increasing.

[0084] Example 5

[0085] The only difference from Example 2 is that the photovoltaic silicon powder is distributed in a single scale, and the particle size is 100 mesh.

[0086] Example 6

[0087] A wood-plastic composite material is prepared from the following raw materials: 30 parts by weight of wood flour, 25 parts by weight of PE, 35 parts by weight of photovoltaic silicon powder, 8 parts by weight of a compatibilizer, 3 parts by weight of a coupling agent, 2 parts by weight of stearic acid, 1 part by weight of carbon black, and 5 parts by weight of deionized water.

[0088] The specific process is the same as that of Example 1, wherein the first photovoltaic silicon powder is 60-80 mesh, and the second photovoltaic silicon powder is 130-180 mesh, and they are added in a weight ratio of 1:1.

[0089] Table 1. Effect of photovoltaic silicon powder content on the properties of wood-plastic composites

[0090]

[0091]

[0092] in conclusion:

[0093] Examples 1 and 2 exhibited optimal PV silicon powder content, achieving peak mechanical properties (e.g., shear strength and compressive strength) and maintaining stable processing performance. However, increasing PV silicon powder content resulted in decreased interfacial compatibility, uneven dispersion, embrittlement, and increased processing difficulty. Decreasing PV silicon powder content resulted in less pronounced reinforcement, a loose matrix structure, and lower-than-expected density and strength.

[0094] In order to verify the advantages of photovoltaic silicon powder in compatibility and dispersibility, the following comparative experiment was designed to replace photovoltaic silicon powder with an equal amount of silicon dioxide or wollastonite:

[0095] Comparative Example 3

[0096] The only difference from Example 2 is that silicon dioxide particles are used instead of photovoltaic silicon powder, and the particle size is 100 mesh.

[0097] Comparative Example 4

[0098] The only difference from Example 3 is that silicon dioxide particles are used instead of photovoltaic silicon powder, and the particle size is 100 mesh.

[0099] Comparative Example 5

[0100] The only difference from Example 2 is that wollastonite particles are used instead of photovoltaic silicon powder, and the particle size is 100 mesh.

[0101] Comparative Example 6

[0102] The only difference from Example 3 is that wollastonite particles are used instead of photovoltaic silicon powder, and the particle size is 100 mesh.

[0103] Table 2. Performance comparison and advantages of silica fume and other inorganic fillers

[0104]

[0105] As can be seen from Example 2 and Comparative Examples 1, 3, and 5, photovoltaic silicon powder has better dispersibility in wood-plastic composites than other inorganic fillers. Even at a higher content, photovoltaic silicon powder can still be evenly dispersed. Photovoltaic silicon powder has high surface activity after acid washing. Through acid washing, impurities on the surface of silicon powder are removed, exposing a purer silicon surface. In addition, hydrofluoric acid treatment may etch the silicon surface, forming more pores or microstructures, increasing the surface area. A larger surface area means more contact points, which can enhance the interaction with other materials (such as compatibilizers); at the same time, acid washing may introduce surface functional groups (such as hydroxyl groups), which can react with compatibilizers (such as maleic anhydride-grafted polypropylene) to form a stronger interfacial bond; while silica and wollastonite have low surface polarity and are prone to agglomeration.

[0106] The wood-plastic composite material of the present invention uses photovoltaic silicon powder with multi-scale distribution (60-200 mesh) after graded grinding. The addition of photovoltaic silicon powder significantly reduces the porosity of the material. Its multi-scale particles can effectively fill the pores between wood powder and PE matrix, forming a dense network structure and improving the density. Other fillers have a single particle size and poor filling effect.

[0107] Furthermore, the irregular surface of the photovoltaic silicon powder forms a mechanical anchor with the wood flour fibers, creating a physical interlock and improving shear resistance. The high modulus of the photovoltaic silicon powder can effectively transfer external loads and delay crack propagation.

[0108] The photovoltaic silicon powder used in the present invention is a waste resource, has a lower cost than commercially available inorganic fillers, and does not require additional surface modification treatment.

Claims

1. A wood-plastic composite material for recycling waste photovoltaic modules, characterized in that: The wood-plastic composite material comprises the following components: 25-65 parts by weight of photovoltaic silicon powder, preferably with a particle size of 60 to 200 mesh; 10-30 parts by weight of thermoplastic; 10-45 parts by weight of wood fiber powder; 5-10 parts by weight of compatibilizer; 2-5 parts by weight of coupling agent; 1-3 parts by weight of stearic acid, and 1-3 parts by weight of optional pigment, The photovoltaic silicon powder is obtained by recycling waste photovoltaic modules.

2. The wood-plastic composite material according to claim 1, characterized in that The recycling process includes: (1) crushing and sorting, wherein the waste photovoltaic modules are physically crushed to obtain coarse silicon powder after sorting; (2) Aluminum removal: removing aluminum by soaking in alkaline solution; (3) Silver extraction: removing silver by soaking in acid; (4) Remove the passivation layer by soaking in hydrofluoric acid; (5) Filter and dry.

3. The wood-plastic composite material according to claim 1 or 2, characterized in that: The photovoltaic silicon powder includes a first photovoltaic silicon powder having a particle size of 60-100 mesh, preferably 60-80 mesh; and a second photovoltaic silicon powder having a particle size greater than 100 mesh and less than 200 mesh, preferably 130-180 mesh; wherein the first photovoltaic silicon powder and the second photovoltaic silicon powder are added in a weight ratio of 1:1 to 1:2, preferably 1:1.3 to 1:1.7; Preferably, the photovoltaic silicon powder has a weight content of not less than 25% and not more than 70% in the wood-plastic composite material, more preferably not less than 30% and not more than 60%; and / or The thermoplastic is one or more selected from polyethylene, polypropylene and polyvinyl chloride; and / or The wood fiber powder is a combination of one or more selected from wood powder, bamboo powder, crop straw powder and rice husk powder; and / or The compatibilizer is one or more selected from maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, and maleic anhydride grafted polystyrene, preferably one or more selected from maleic anhydride grafted polypropylene and maleic anhydride grafted polyethylene; and / or The coupling agent is one or more selected from silane coupling agents, titanate coupling agents, and maleic anhydride grafted polyolefins, preferably silane coupling agents.

4. A method for preparing a wood-plastic composite material for recycling waste photovoltaic modules, characterized in that: The method comprises the following steps: (1) Recycling waste photovoltaic modules to obtain photovoltaic silicon powder; (2) grinding the photovoltaic silicon powder and screening it for later use; preferably, the particle size of the photovoltaic silicon powder obtained by screening is 60-200 mesh; (3) 25-65 parts by weight of photovoltaic silicon powder, 10-30 parts by weight of thermoplastic plastic, 10-45 parts by weight of wood fiber powder, 5-10 parts by weight of compatibilizer, 2-5 parts by weight of coupling agent, 1-3 parts by weight of stearic acid, 1-3 parts by weight of optional pigment and 5-10 parts by weight of water are mixed uniformly, and then injection molding or extrusion molding is performed to obtain the wood-plastic composite material.

5. The method according to claim 4, characterized in that The recycling process includes crushing and sorting, aluminum removal, silver extraction, and passivation layer removal, followed by filtration and drying, wherein: The aluminum removal comprises soaking in 1-2 mol / L sodium hydroxide solution for 1-2 hours; and / or The silver extraction comprises soaking in a 1-3 mol / L nitric acid solution for 40-50 minutes to remove silver; and / or The passivation layer removal comprises soaking in 8% v / v hydrofluoric acid for 20-40 minutes; and / or The drying comprises drying at 60° C. to 90° C. for 120 to 180 minutes after rinsing.

6. The method according to claim 4, characterized in that The step (3) comprises: a) respectively taking a first photovoltaic silicon powder, a thermoplastic plastic, and a wood fiber and heating and mixing them to form a primary injection molding compound; b) subsequently adding a second photovoltaic silicon powder, a compatibilizer, a coupling agent, stearic acid, an optional pigment, and water for secondary mixing to form a secondary injection molding compound; kneading the secondary injection molding compound; extruding or injection molding the compound; and cutting the extruded or injection molded plate to obtain the wood-plastic composite material; The particle size of the first photovoltaic silicon powder is 60-100 mesh, preferably 60-80 mesh; the particle size of the second photovoltaic silicon powder is greater than 100 and less than 200 mesh, preferably 130-180 mesh.

7. The method according to claim 6, characterized in that The weight ratio of the first photovoltaic silicon powder to the second photovoltaic silicon powder is 1:1 to 1:2, preferably 1:1.3 to 1:1.7, and most preferably 1:1.

5.

8. The method according to any one of claims 4 to 7, characterized in that The thermoplastic is one or more selected from polyethylene, polypropylene and polyvinyl chloride; and / or The wood fiber powder is a combination of one or more selected from wood powder, bamboo powder, crop straw powder, and rice husk powder; and / or The compatibilizer is one or more selected from maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, and maleic anhydride grafted polystyrene, preferably one or more selected from maleic anhydride grafted polypropylene and maleic anhydride grafted polyethylene; and / or The coupling agent is one or more selected from silane coupling agents, titanate coupling agents, and maleic anhydride grafted polyolefins, preferably silane coupling agents.

9. The method according to any one of claims 4 to 7, characterized in that In step (3), the plasticizing temperature is 170-220° C., preferably 190-210° C.; the mold temperature is 130-190° C., preferably 160-180° C.; and the pressure is 0.1-0.7 MPa, preferably 0.5-0.6 MPa.

10. The method according to any one of claims 4 to 7, characterized in that In step (3), the primary mixture is cut into blocks of 1-3 cm in size after the initial mixing, and then the secondary mixing is carried out.

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