Bio-based pe multi-layered structure article based on blow molding and 3D printing process and preparation thereof

Abstract

This invention discloses a bio-based PE multilayer structure product and its preparation based on blow molding and 3D printing processes, comprising: S1. blow molding peroxide and bio-based high-density polyethylene to obtain a hollow product; S2. spraying an activation liquid onto the surface of the hollow product, and then scanning the surface with a CO2 laser to obtain a modified hollow product; S3. melt-blending bio-based polyethylene, ethylene-butyl acrylate-maleic anhydride copolymer, and a nucleating agent to obtain a 3D printing filament; S4. preheating the modified hollow product, and using the 3D printing filament for fused deposition modeling, followed by annealing to obtain the bio-based PE multilayer structure product; This application, through material and process design, successfully solves the core technical problems of insufficient bonding strength and easy delamination between layers caused by interfacial chemical inertness and thermal stress in the post-blow molding and post-3D printing composite process of bio-based polyethylene.

Description

Technical Field

[0001] This invention relates to the field of bio-based PE multilayer structure products technology, and in particular to a bio-based PE multilayer structure product based on blow molding and 3D printing processes and its preparation. Background Technology

[0002] Currently, renewable polymers such as bio-based polyethylene are increasingly widely used in packaging, daily necessities, and other fields. However, while bio-based polyethylene inherits the good processability and chemical resistance of traditional polyethylene, it also retains its low surface energy and strong chemical inertness, which poses significant interfacial bonding challenges when secondary compounding or surface functionalization is required.

[0003] Blow molding can efficiently produce lightweight, seamless hollow products, while fused deposition modeling (FDM) can flexibly construct complex external structures or textures. Combining these two processes promises to achieve a complementary advantage in product lightweighting and personalized design. Existing technologies have explored 3D printing on blow-molded surfaces for reinforcement or modification, but these processes are mostly applicable to polar engineering plastics or specially treated substrates. For non-polar, inert surfaces like bio-based polyethylene, direct printing often results in interlayer delamination due to weak interfacial adhesion, severely limiting the practicality and reliability of this composite process.

[0004] Therefore, a technical solution is needed to address the problems of insufficient interfacial bonding strength and easy delamination between bio-based polyethylene blow-molded products and 3D printed layers. Summary of the Invention

[0005] In view of this, this application provides a bio-based PE multilayer structure product based on blow molding and 3D printing processes and its preparation, which is used to solve the problem of poor interfacial bonding strength of bio-based polyethylene in the blow molding and 3D printing composite process.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for preparing a bio-based PE multilayer structure product based on blow molding and 3D printing processes, comprising the following steps: S1. Peroxide and bio-based high-density polyethylene are blow-molded to obtain hollow products; S2. Spray an activation liquid onto the surface of the hollow product, and then scan the surface with a CO2 laser to obtain the modified hollow product; S3. Bio-based polyethylene, ethylene-butyl acrylate-maleic anhydride copolymer and nucleating agent are melt-blended to obtain 3D printing filament; S4. Preheat the modified hollow product and use 3D printing filament for fused deposition modeling, followed by annealing to obtain a bio-based PE multilayer structure product.

[0007] Preferably, in step S1, the peroxide is di-tert-butyl peroxide; the amount of peroxide used is 0.1-0.5% of the bio-based high-density polyethylene.

[0008] Preferably, between step S1 and step S2, the method further includes controlling the surface temperature of the hollow product to 60-75°C.

[0009] Preferably, in step S2, the activation solution includes ferric ammonium citrate, hydrogen peroxide, citric acid, and water.

[0010] Preferably, the concentration of ferric ammonium citrate in the activation solution is 1-3 wt%.

[0011] Preferably, in step S2, the power of surface scanning is 8-12W, the scanning speed is 400-600mm / s, and the scanning pattern is a grid pattern with a line width of 40-60μm and a spacing of 100-200μm.

[0012] Preferably, in step S3, the amount of bio-based polyethylene is 80-95% by mass, the amount of ethylene-butyl acrylate-maleic anhydride copolymer is 5-10%, and the amount of nucleating agent is 2-5%.

[0013] Preferably, in step S4, the modified hollow product is preheated to 100-115°C.

[0014] Preferably, in step S1, the melt index (190℃ / 2.16kg) of the bio-based high-density polyethylene is 0.5-1.0g / 10min; in step S3, the melt index (190℃ / 2.16kg) of the bio-based polyethylene is 5-8g / 10min.

[0015] Secondly, this application provides a bio-based PE flowerpot.

[0016] The beneficial effects of this application are as follows: This application successfully solves the core technical problems of insufficient bonding strength and easy delamination between layers caused by interfacial chemical inertness and thermal stress in the post-blow molding and post-3D printing composite process of bio-based polyethylene by adding peroxide to the blow molding substrate, using laser-excited synergistic oxidation to construct micro-grooves and highly active chemical regions on the surface of the product, developing special printing filaments containing reactive compatibilizers, and combining the systematic design of processes such as preheating, online rolling and programmed annealing. This achieves high-strength and high-stability interfacial bonding between the two layers, making it possible to prepare products with both lightweight hollow structure and complex personalized shape using fully bio-based polyethylene materials. Detailed Implementation

[0017] The embodiments of the technical solution of this application will be described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0018] Terminology Explanation Fused deposition modeling (FDM) involves heating thermoplastic material to a molten or semi-fluid state inside the printhead, extruding it through a nozzle, and depositing, stacking, and cooling it layer by layer according to a preset digital model path to create the outer layer of a three-dimensional solid structure on the surface of the product.

[0019] This application provides a method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes, including the following steps: S1. Peroxide and bio-based high-density polyethylene are blow-molded to obtain hollow products; S2. Spray an activation liquid onto the surface of the hollow product, and then scan the surface with a CO2 laser to obtain the modified hollow product; S3. Bio-based polyethylene, ethylene-butyl acrylate-maleic anhydride copolymer and nucleating agent are melt-blended to obtain 3D printing filament; S4. Preheat the modified hollow product and use 3D printing filament for fused deposition modeling, followed by annealing to obtain a bio-based PE multilayer structure product.

[0020] In this application, the inherent defects of bio-based PE in composite processing are overcome through systematic design of materials and processes. Specifically, in step S1, a specific peroxide is added to the blow molding raw material, which serves as an internal reaction source for deep oxidation in subsequent laser treatment. In step S2, a CO2 laser is used to scan the surface sprayed with a photothermal activation liquid. This process simultaneously performs two functions: first, it forms micro-grooves through thermal etching to construct a mechanical interlocking structure; second, the local high temperature of the laser simultaneously excites the peroxide in the matrix and the oxidant in the liquid film, resulting in a vigorous oxidation reaction within the grooves, thereby generating highly active chemical regions rich in polar functional groups such as carboxyl groups in situ on the inert bio-based PE surface. The special printing filament prepared in step S3 contains a reactive compatibilizer, whose active groups can be targeted to chemically bond with the highly active carboxyl regions generated in step S2. In step S4, the temperature difference between the preheated matrix and the printing melt is reduced, avoiding excessive cooling of the melt when it comes into contact with the cold matrix, thus creating the necessary conditions for molecular chain diffusion and interfacial reaction. Online pressing ensures that the melt fully fills the micro-grooves and strengthens the mechanical interlocking. Therefore, this application solves the technical problems of insufficient interfacial bonding strength and easy delamination between layers in the "blow molding followed by melt deposition printing" process of bio-based polyethylene by systematically combining the above steps.

[0021] In some embodiments, in step S1, the peroxide is di-tert-butyl peroxide; the amount of peroxide used is 0.1-0.5% of the bio-based high-density polyethylene.

[0022] In this embodiment, the half-life of di-tert-butyl peroxide at a blow molding temperature of 175°C is greater than 1 hour. The addition of peroxide provides latent reaction sites for the laser treatment in step S2. When the laser induces local high temperature, the peroxide decomposes to generate active free radicals, which have a synergistic effect with the oxidant in the activation liquid, making the oxidation reaction in the laser scanning area more intense and in-depth. This is beneficial for the subsequent printing material to form a stronger chemical bond with it, thereby helping to solve the problem of weak interfacial bonding. If the concentration of peroxide is less than 0.1%, the synergistic effect is not significant, and the improvement on interfacial strength is limited. If the concentration is higher than 0.5%, it affects the stability of the blow molding process.

[0023] In some embodiments, between steps S1 and S2, the method further includes controlling the surface temperature of the hollow article to 60-75°C.

[0024] In this embodiment, the temperature range is beneficial for maintaining the mobility of bio-based PE molecular chain segments, promoting the uniform spreading and initial adsorption of the subsequent activation liquid on the surface, laying the foundation for laser-induced modification, and avoiding product deformation due to excessive temperature. In order to control the surface temperature of the hollow product, in some embodiments, the cooling parameters of the blow molding die are adjusted, and the product is quickly transferred to the processing station using a heat preservation and transfer device after demolding, with an infrared thermometer used for monitoring during the process.

[0025] In some embodiments, in step S2, the activation solution includes ferric ammonium citrate, hydrogen peroxide, citric acid, and water.

[0026] In this embodiment, the role of the activating liquid is to initiate and participate in the rapid oxidation and modification reaction on the surface of the product under CO2 laser irradiation. Ferric ammonium citrate absorbs laser energy of a specific wavelength and converts it into heat energy. Hydrogen peroxide decomposes under heat, generating active oxygen species to oxidize the polyethylene surface. Citric acid provides an acidic environment to stabilize hydrogen peroxide and participates in surface modification. Through the synergistic effect of the components, laser scanning is used for chemical modification, transforming the inert PE surface into a chemically bondable, highly active surface, thus solving the problem of poor chemical compatibility at the blow molding and 3D printing interface.

[0027] In some embodiments, the concentration of ferric ammonium citrate in the activation solution is 1-3 wt%.

[0028] In this embodiment, limiting the concentration of ferric ammonium citrate is beneficial to the surface treatment effect in step S2. When the concentration is below 1 wt%, the photothermal conversion efficiency is insufficient, and it is impossible to generate a local high temperature sufficient to initiate effective oxidation and micro-etching, resulting in shallow surface modification, low density of active functional groups, and limited enhancement effect on subsequent interface bonding. When the concentration is above 3 wt%, it may lead to an increase in the viscosity of the activation solution, affecting the uniformity of spraying, and excessive energy absorption may cause substrate burns or generate too many by-products to contaminate the interface.

[0029] In some embodiments, in step S2, the power of surface scanning is 8-12W, the scanning speed is 400-600mm / s, and the scanning pattern is a grid pattern with a line width of 40-60μm and a spacing of 100-200μm.

[0030] In this embodiment, CO2 laser scanning ensures that microgrooves with a depth of 20-50 μm are instantly formed on the surface of the product, while simultaneously stimulating a full oxidation reaction.

[0031] In some embodiments, in step S3, the amount of bio-based polyethylene is 80-95% by weight, the amount of ethylene-butyl acrylate-maleic anhydride copolymer is 5-10%, and the amount of nucleating agent is 2-5%.

[0032] In this embodiment, the ethylene-butyl acrylate-maleic anhydride copolymer serves as a reactive compatibilizer. Its main chain is compatible with PE, and the maleic anhydride (MAH) functional groups on the side chains can chemically react with the carboxyl groups (-COOH) generated on the surface of the blown layer in step S2 during the melt printing process to form strong chemical bonds (such as anhydride bonds or ester bonds), which is beneficial to improving interfacial bonding. The nucleating agent helps to increase its crystallization rate, thereby reducing the microscopic internal stress generated during the cooling and solidification of the printed outer layer due to the asynchronous crystallization and shrinkage with the blown inner layer, and avoiding interface damage and delamination problems caused by stress concentration during subsequent use.

[0033] In some embodiments, in step S4, the modified hollow product is preheated to 100-115°C.

[0034] In this embodiment, preheating can significantly reduce the temperature difference between the melt and the blown substrate, significantly slow down the interface cooling rate, and provide more time for the diffusion of melt molecular chains, full filling of microgrooves, and full contact and chemical bonding with surface-active functional groups.

[0035] In some embodiments, the preheating method of step S4 is infrared heating, which uniformly heats the outer surface of the product from room temperature to 100-115°C within 5-10 minutes, and maintains this temperature throughout the first layer printing process, with the temperature difference controlled within ±2°C.

[0036] In some embodiments, the modified hollow product is preheated and fused deposition modeling is performed using 3D printing filament. The first layer is printed at a temperature of 155-165°C and a speed of 10-20 mm / s. During the printing process, a temperature-controlled pressure roller is used to roll the deposited melt. After annealing, a bio-based PE multilayer structure product is obtained. The annealing conditions are as follows: constant temperature treatment at 60-70°C for 20-40 minutes, followed by slow cooling to 40°C at a rate of 1-2°C / min, and finally natural cooling to room temperature.

[0037] In this embodiment, the first layer uses a higher temperature and a lower speed to provide sufficient heat and time in the interface region, maximizing the flow, wetting, diffusion, and chemical reaction of the melt at the interface. The synchronous rolling of the online temperature-controlled pressure roller applies a gentle and continuous thermomechanical force to the newly deposited melt, which further forces the melt to adhere tightly to the substrate surface and penetrate into the microgrooves, eliminating any gas that may be trapped at the interface and ensuring the integrity of the physical contact. The subsequent annealing process has a dual function: the isothermal section provides additional reaction driving force and time for incomplete chemical reactions in the interface region (such as the reaction between MAH and -COOH) and promotes further interdiffusion of molecular chains; the slow program cooling is beneficial for the internal stress accumulated in the interface and the overall structure during rapid printing, thereby ensuring high strength and high stability of the interface bonding and ultimately effectively solving the problem of easy peeling between layers.

[0038] In some embodiments, in step S1, the melt index (190℃ / 2.16kg) of bio-based high-density polyethylene is 0.5-1.0g / 10min; in step S3, the melt index (190℃ / 2.16kg) of bio-based polyethylene is 5-8g / 10min.

[0039] In this embodiment, the blow molding process uses low melt index raw materials with high melt strength, while the fused deposition modeling process uses high melt index raw materials with good flowability, in order to adapt to the processing characteristics of the two processes and ensure the molding quality of each stage.

[0040] Specifically, the preparation steps of the bio-based PE multilayer structure product based on blow molding and 3D printing processes in this application are as follows: S1. Mix 0.1%-0.5% by weight of di-tert-butyl peroxide with bio-based high-density polyethylene with a melt index of 0.5-1.0 g / 10min, and blow mold the mixture to obtain a hollow inner liner. Control the outer surface temperature of the product after molding to be 60-75℃. S2. Add 1-3wt% ferric ammonium citrate to an activation solution prepared from hydrogen peroxide, citric acid and water, stir evenly, and spray the activation solution onto the outer surface of the inner liner of the above-mentioned warm hollow product. Then use a CO2 laser at a power of 8-12W and a speed of 400-600mm / s to scan the product in a grid pattern with a line width of 40-60μm and a spacing of 100-200μm to obtain the modified hollow product. S3. Bio-based polyethylene, ethylene-butyl acrylate-maleic anhydride copolymer and aryl phosphate nucleating agent with a melt index of 5-8 g / 10min are melt-blended, granulated and drawn into filaments at a mass ratio of 80-95:5-10:2-5 to obtain 3D printing filaments with a diameter of 1.75±0.05mm. S4. Using infrared heating, the outer surface of the modified hollow product treated in step S2 is uniformly preheated from room temperature to 100-115℃ within 5-10 minutes and kept at a constant temperature (±2℃). The filament obtained in step S3 is used for fused deposition printing. The first layer is printed at a temperature of 155-165℃ and a speed of 10-20mm / s. A pressure roller at a temperature of 80-90℃ is used to simultaneously roll the deposited melt at a pressure of 0.1-0.3MPa. The subsequent layer printing temperature is adjusted to 135-145℃ and the speed is adjusted to 30-50mm / s. After printing, the composite multilayer structure product is placed in a constant temperature environment of 60-70℃ for 20-40 minutes, then cooled to 40℃ at a rate of 1-2℃ / min, and finally cooled naturally to room temperature to obtain the bio-based PE multilayer structure product.

[0041] This application provides a bio-based PE multilayer structure product, which is made from bio-based PE as raw material and is obtained by blow molding followed by 3D printing.

[0042] The following specific embodiments further illustrate this solution.

[0043] Example 1 A bio-based PE multilayer structure product based on blow molding and 3D printing processes is prepared by the following steps: S1. Di-tert-butyl peroxide, accounting for 0.15% of the weight of bio-based high-density polyethylene, is mixed evenly with bio-based high-density polyethylene with a melt index of 0.8 g / 10 min in a high-speed mixer. The mixture is fed into a single-screw blow molding machine, and a preform is extruded and blow molded at 155-180℃ to obtain a hollow multi-layer structure inner liner. By adjusting the mold cooling time and monitoring with an infrared thermometer, the outer surface temperature of the product after demolding is controlled to be 68℃. S2. Add ferric ammonium citrate at a ratio of 2.0 wt% to an activation solution prepared by hydrogen peroxide, citric acid and water in a weight ratio of 5:2:93, and stir for 30 minutes until completely dissolved. Use an ultrasonic atomizing spraying device to uniformly spray the newly prepared activation solution onto the outer surface of the inner liner of the warm hollow multilayer structure product to form a continuous liquid film. Then, use a 50W CO2 laser at a power of 10W and a scanning speed of 500 mm / s to scan the surface covered by the liquid film in a grid pattern with a line width of 50μm and a spacing of 150μm. After scanning, regular microgrooves with a depth of about 30-40μm are formed on the surface of the product. S3. Bio-based polyethylene with a melt index of 7.0 g / 10min, ethylene-butyl acrylate-maleic anhydride copolymer and aryl phosphate nucleating agent were melt-blended in a mass ratio of 88:7:4 using a twin-screw extruder at 170-185℃ and granulated underwater. The resulting granules were dried and then drawn, cooled and sized by a single-screw wire extruder at 175-180℃ to produce 3D printing filaments with a diameter of 1.75±0.03mm. S4. Using a ring-shaped infrared heater, the outer surface of the inner liner of the multi-layer structure product processed in step S2 is uniformly preheated from room temperature to 108°C within 8 minutes and kept at a constant temperature. The filament obtained in step S3 is used for melt deposition printing. During the first layer printing, the printhead temperature is set to 162°C, the printing speed is set to 15mm / s, and a silicone pressure roller integrated at the rear of the printhead at a temperature of 85°C is used to synchronously roll the freshly deposited melt at a pressure of 0.25MPa. From the second layer onwards, the printhead temperature is adjusted to 142°C, the printing speed is adjusted to 40mm / s, and the pressure roller pressure is adjusted to 0.15MPa. Printing continues until the preset structure is completed. After printing, the composite multi-layer structure product is placed in a 65°C forced-air oven for constant temperature treatment for 30 minutes. Then, the temperature is controlled to drop to 40°C at a set rate of 1.5°C / min. Finally, the oven is turned off and allowed to cool naturally to room temperature, thus obtaining the bio-based PE multi-layer structure product.

[0044] Example 2 A method for preparing a bio-based PE multilayer structure product based on blow molding and 3D printing technology is the same as that in Example 1, except that the amount of peroxide in step S1 is 0.1%, the concentration of ferric ammonium citrate in the activation solution in step S2 is 1wt%, and the preheating temperature in step S4 is 102℃.

[0045] Example 3 A method for preparing a bio-based PE multilayer structure product based on blow molding and 3D printing technology is the same as that in Example 1, except that the amount of peroxide used in step S1 is 0.5%, the concentration of ferric ammonium citrate in the activation solution in step S2 is 3wt%, and the preheating temperature in step S4 is 113℃.

[0046] Examples 4-5 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that the amount of peroxide used in step S1 is 0.1%, 0.3%, and 0.5% respectively.

[0047] Examples 6-7 A method for preparing a bio-based PE multilayer structure product based on blow molding and 3D printing technology. The other contents are the same as those in Example 1, except that in step S2, the amount of ferric ammonium citrate added is 1wt% and 3wt% respectively.

[0048] Comparative Example 1 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that di-tert-butyl peroxide is not added.

[0049] Comparative Example 2 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that no activating solution is added.

[0050] Comparative Example 3 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that CO2 laser scanning is not used.

[0051] Comparative Example 4 A bio-based PE multilayer structure product based on blow molding and 3D printing technology and its preparation are described. The other contents are the same as those in Example 1, except that preheating is not performed in step S4.

[0052] Comparative Example 5 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that no nucleating agent is added.

[0053] Comparative Example 6 A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes is the same as in Example 1, except that ferric ammonium citrate is not added.

[0054] Testing and Evaluation The T-peel strength of blow-molded and 3D interfaces of multilayer structural products obtained from different examples and comparative examples was tested according to the standard test method (T-peel test) for the peel resistance of adhesives in ASTM D1876-08.

[0055] Integrity of the first layer after thermal cycling: The multi-layer structure product sample is placed in an alternating high and low temperature environment for cycling. It is kept at 60℃ for 2 hours, and then quickly switched to -10℃ for 2 hours. This cycle is repeated 50 times. After the cycle, the first printed layer is visually inspected, observed under a microscope, or gently peeled off to determine whether there is cracking, warping, bubbling or separation between it and the substrate. If the above phenomena occur, it is determined to be defective. If the above phenomena do not occur, it is determined to be intact.

[0056] Table 1 Test Results

[0057] This application successfully solves the core technical problems of insufficient bonding strength and easy delamination between layers caused by interfacial chemical inertness and thermal stress in the post-blow molding and post-3D printing composite process of bio-based polyethylene by adding peroxide to the blow molding substrate, using laser-excited synergistic oxidation to construct micro-grooves and highly active chemical regions on the surface of the product, developing special printing filaments containing reactive compatibilizers, and combining a systematic design of processes such as preheating, online rolling and programmed annealing. This achieves a high-strength and high-stability interfacial bond between the two layers, making it possible to prepare products with both lightweight hollow structures and complex personalized shapes using fully bio-based polyethylene materials.

[0058] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes, characterized in that, Includes the following steps: S1. Peroxide and bio-based high-density polyethylene are blow-molded to obtain hollow products; S2. Spray an activation liquid onto the surface of the hollow product, and then scan the surface with a CO2 laser to obtain a modified hollow product; S3. Bio-based polyethylene, ethylene-butyl acrylate-maleic anhydride copolymer and nucleating agent are melt-blended to obtain 3D printing filament; S4. Preheat the modified hollow product, and use the 3D printing filament for fused deposition modeling, followed by annealing to obtain the bio-based PE multilayer structure product.

2. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S1, the peroxide is di-tert-butyl peroxide; the amount of the peroxide used is 0.1-0.5% of the bio-based high-density polyethylene.

3. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, Between steps S1 and S2, the method further includes controlling the surface temperature of the hollow product to 60-75°C.

4. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S2, the activation solution includes ferric ammonium citrate, hydrogen peroxide, citric acid, and water.

5. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, The concentration of ferric ammonium citrate in the activation solution is 1-3 wt%.

6. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S2, the power of the surface scanning is 8-12W, the scanning speed is 400-600mm / s, and the scanning pattern is a grid pattern with a line width of 40-60μm and a spacing of 100-200μm.

7. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S3, by mass, the amount of bio-based polyethylene is 80-95%, the amount of ethylene-butyl acrylate-maleic anhydride copolymer is 5-10%, and the amount of nucleating agent is 2-5%.

8. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S4, the modified hollow product is preheated to 100-115°C.

9. The method for preparing bio-based PE multilayer structure products based on blow molding and 3D printing processes according to claim 1, characterized in that, In step S1, the melt index (190℃ / 2.16kg) of the bio-based high-density polyethylene is 0.5-1.0g / 10min; in step S3, the melt index (190℃ / 2.16kg) of the bio-based polyethylene is 5-8g / 10min.

10. A bio-based PE flowerpot prepared by the method according to any one of claims 1-9.

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