A polypropylene composite material and its preparation method and application in the preparation of a balance vehicle
By modifying POE to form hydrogen bonds and chemical bonds with ultrafine calcium carbonate and nylon 6, the compatibility is improved, the compatibility problem of polypropylene, nylon 6 and calcium carbonate is solved, and the mechanical properties of polypropylene composites are improved, making it suitable for high-strength products such as children's balance cars and plastic toys.
Patent Information
- Application Number
- CN202510095522.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2045-01-21
AI Technical Summary
The compatibility between polypropylene, nylon 6 and calcium carbonate is poor, resulting in insufficient mechanical properties of polyethylene materials.
By introducing modified POE, the hydroxyl groups, ether bonds and amide bonds on its side chain polymer molecular chain are used to form hydrogen bonds and chemical bonds with the surface of ultrafine calcium carbonate, thereby improving the surface modification of ultrafine calcium carbonate. The similar polarity of modified POE and nylon 6 is used to improve the compatibility between the two. At the same time, the modified POE has good compatibility with polypropylene, forming an alloy system.
The tensile properties, impact strength and flexural strength of polypropylene composite materials are improved, making them suitable for high-strength products such as children's balance cars, baby carriages and plastic toys.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of polypropylene, and in particular to a polypropylene composite material, a preparation method thereof, and application in the preparation of a balance vehicle. Background Art
[0002] Polypropylene is transparent, low-density, lightweight, and possesses excellent antibacterial, wear-resistant, and electrical insulating properties. It is widely used in products such as children's balance bikes, strollers, plastic toys, and alloy toys. Nylon 6 boasts high mechanical strength and excellent impact resistance. Compounding it with polypropylene can complement the advantages of both materials to create a high-performance alloy. A compatibilizer is often added to improve compatibility between the two.
[0003] POE (ethylene-octene copolymer) is an elastomeric material with excellent performance. As a polyolefin-based diamond mesh, it exhibits excellent compatibility with polypropylene and is therefore crucial for toughening and modifying materials such as polypropylene. Patent publication number CN105504512B discloses a shallow-sink-reinforced polypropylene material and its preparation method. Using polypropylene, nylon resin, maleic anhydride-grafted POE, and a compatibilizer as raw materials, the resulting polypropylene material exhibits advantages such as resistance to sink marks, scratches, and high strength. Compared to the polypropylene composite material in the patent, the present invention exhibits higher tensile properties, impact strength, and flexural strength. Summary of the Invention
[0004] The technical problem solved by the present invention is to solve the problem of poor compatibility among polypropylene, nylon 6 and calcium carbonate, and to improve the mechanical properties of polyethylene materials.
[0005] Technical solution: A polypropylene composite material, comprising the following raw materials in parts by weight: 100 parts of polypropylene, 15-30 parts of nylon 6, 5-25 parts of ultrafine calcium carbonate, 8-15 parts of modified POE, and 0.4-0.6 parts of antioxidant.
[0006] Preferably, the preparation method of the polypropylene composite material is as follows: modified POE and ultrafine calcium carbonate are added to a mixer, blended at 75-90°C for 2-3h, then polypropylene, nylon 6, and an antioxidant are added, mixed at 70-80°C for 40-60min, and the blend is added to a twin-screw extruder, melt-blended at 180-235°C, extruded, and injection molded in an injection molding machine at 220-230°C to obtain a polypropylene composite material.
[0007] Preferably, the preparation method of modified POE is:
[0008] (1) Add ethylene glycol diglycidyl ether and diimino monomer in a molar ratio of 1:(1-1.1) to tetrahydrofuran, heat to 50-60°C, stir and react for 8-12 hours, distill under reduced pressure, wash with ethanol, and dry to obtain a hydroxy polymer. The preparation reaction formula is:
[0009] .
[0010] (2) In an ice bath, add hydroxyl polymer, triethylamine, and acryloyl chloride monomer in a mass ratio of 100:(1.7-2.6):(1.5-2.3) to N,N-dimethylformamide, then stir and react at room temperature for 4-6 hours, distill under reduced pressure, wash with ethanol, and dry to obtain an acrylate-based polymer. The reaction formula is:
[0011] .
[0012] (3) Ethylene-octene copolymer (POE), acrylate-based polymer, and diisopropylbenzene peroxide (DPC) in a mass ratio of 100:(4-10):(0.07-0.18) were mixed and melt-grafted at 170-180°C for 7-10 minutes in a torque rheometer. The product was added to xylene and heated to reflux. Then, acetone was added. After filtering, the precipitate was extracted with acetone and dried to obtain modified POE.
[0013] Preferably, the acryloyl chloride monomer is acryloyl chloride or methacryloyl chloride.
[0014] Preferably, the preparation method of the diimino monomer is as follows: N-Boc-N-methylethylenediamine (CAS No. ), triethylamine, and diacyl chloride are added to dichloromethane in an ice bath at a molar ratio of (2-2.2):(2-2.2):1, followed by stirring at room temperature for 6-8 hours, distillation under reduced pressure, washing with water, and drying. The product is added to a 3 mol / L hydrogen chloride ethyl acetate solution, stirred at room temperature for 4-5 hours, the Boc protecting group is removed, distillation under reduced pressure, washing with a saturated sodium carbonate solution, and drying to obtain the diimino monomer. The preparation reaction formula is:
[0015] .
[0016] Preferably, the structural formula of the diacyl chloride is , a is any integer between 2 and 4.
[0017] Preferably, the polypropylene composite material is used in the preparation of the balance vehicle.
[0018] The technical effect of the present invention is as follows: the present invention conducts an epoxy addition polymerization reaction between a diimino monomer and ethylene glycol diglycidyl ether to obtain a hydroxyl polymer, part of the hydroxyl groups of which are then reacted with (meth)acryloyl chloride to obtain an acrylate-based polymer, and the introduced alkenyl groups are melt-grafted onto a POE ethylene-octene copolymer to obtain a modified POE, thereby grafting a polymer molecular chain containing hydroxyl groups, ether bonds and amide bond groups onto the side chains of the POE.
[0019] The present invention blends polypropylene, nylon 6, ultrafine calcium carbonate, modified POE etc. to obtain polypropylene composite material. The hydroxyl group, the ether bond of the polymer molecular chain introduced by the side chain grafting of modified POE can form hydrogen bonds, chemical bonds and other interactions with the hydroxyl surface of ultrafine calcium carbonate, thereby realizing the surface modification and modification of POE to ultrafine calcium carbonate, and the side chain polymer of modified POE contains a large amount of amide bonds, has similar polarity to the polyamide molecular chain of nylon 6, makes modified POE and nylon 6 also have good similar compatibility, while modified POE contains polyolefin backbone, has very high compatibility with polypropylene, so that modified POE can be used as compatibilizer, simultaneously improves the compatibility between ultrafine calcium carbonate, nylon 6 and polypropylene, makes polypropylene and nylon 6 form a compatible alloy system, ultrafine calcium carbonate intensity is better reinforcing effect, and modified POE also plays good toughening effect, and the polypropylene composite material obtained shows higher tensile properties, impact strength and flexural strength. Better practical application is arranged in aspects such as high-strength and high-performance children's balancing car, baby carriage, plastic toys, alloy toys. DETAILED DESCRIPTION
[0020] The present application is further described in detail below with reference to the embodiments.
[0021] The polypropylene (brand CHC3007) and nylon 6 (brand 8202CHS) in the examples were sourced from Dongguan Juona New Materials Co., Ltd.
[0022] POE ethylene-octene copolymer (brand A4090S) and maleic anhydride grafted POE (brand MA9015) were sourced from Dongguan Kaiwan Engineering Plastics Raw Materials Co., Ltd.
[0023] Ultrafine calcium carbonate, particle size 2000 mesh, sourced from Yongshun Mineral Products Processing Plant in Lingshou County.
[0024] Example 1
[0025] (1) In an ice bath, add 30 mmol N-Boc-N-methylethylenediamine, 30 mmol triethylamine, and 15 mmol succinyl chloride to 50 mL of dichloromethane, and then stir and react at room temperature for 8 h. Distill under reduced pressure, wash with water, and then dry. Add the product to 70 mL of 3 mol / L hydrogen chloride in ethyl acetate solution, stir and react at room temperature for 5 h to remove the Boc protecting group. Distill under reduced pressure, wash with saturated sodium carbonate solution, and dry to obtain a diimino monomer.
[0026] (2) Add 40 mmol of ethylene glycol diglycidyl ether and 40 mmol of diimino monomer to 150 mL of tetrahydrofuran, heat to 60°C, stir and react for 10 hours, distill under reduced pressure, wash with ethanol, and dry to obtain a hydroxyl polymer.
[0027] (3) In an ice bath, 20 g of hydroxy polymer, 0.45 g of triethylamine, and 0.4 g of methacryloyl chloride were added to 250 mL of N,N-dimethylformamide, and the mixture was stirred at room temperature for 4 h. The mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain an acrylate-based polymer.
[0028] (4) 500 g of ethylene-octene copolymer (POE), 20 g of acrylate-based polymer, and 0.35 g of diisopropylbenzene peroxide were mixed and melt-grafted in a torque rheometer at 175 °C for 7 min. The product was added to xylene and heated to reflux. Then, acetone was added. After filtering, the precipitate was extracted with acetone and dried to obtain modified POE.
[0029] (5) Add 0.8 kg modified POE and 0.5 kg ultrafine calcium carbonate into a mixer and blend at 80 °C for 2 h. Then add 10 kg polypropylene, 1.5 kg nylon 6 and 47 g antioxidant 1010 and mix at 70 °C for 60 min. Then add the blend into a twin-screw extruder and melt blend at the temperatures of 1-6 sections at 180 °C, 210 °C, 230 °C, 235 °C, 235 °C and 225 °C. Extrude and injection mold in an injection molding machine at the temperatures of 1-4 sections at 220 °C, 230 °C, 230 °C and 225 °C to obtain a polypropylene composite material.
[0030] Comparative Example 1
[0031] (1) 0.5 kg of ultrafine calcium carbonate, 10 kg of polypropylene, 1.5 kg of nylon 6, and 47 g of antioxidant 1010 were mixed at 70 ° C for 60 min, and the mixture was added to a twin-screw extruder. The temperature of 1-6 sections was 180 ° C, 210 ° C, 230 ° C, 235 ° C, 235 ° C, and 225 ° C for melt blending, extrusion, and injection molding in an injection molding machine. The temperature of 1-4 sections was 220 ° C, 230 ° C, 230 ° C, and 225 ° C to obtain a polypropylene composite material.
[0032] Comparative Example 2
[0033] (1) 0.8 kg of ethylene-octene copolymer (POE) and 0.5 kg of ultrafine calcium carbonate were added to a mixer and blended at 80 °C for 2 h. Then, 10 kg of polypropylene, 1.5 kg of nylon 6 and 47 g of antioxidant 1010 were added and mixed at 70 °C for 60 min. The mixture was then added to a twin-screw extruder and melt-blended at sections 1-6 at temperatures of 180 °C, 210 °C, 230 °C, 235 °C, 235 °C and 225 °C. The mixture was extruded and injection-molded in an injection molding machine at sections 1-4 at temperatures of 220 °C, 230 °C, 230 °C and 225 °C to obtain a polypropylene composite material.
[0034] Comparative Example 3
[0035] (1) 0.8 kg of maleic anhydride grafted POE and 0.5 kg of ultrafine calcium carbonate were added to a mixer and blended at 80 °C for 2 h. Then, 10 kg of polypropylene, 1.5 kg of nylon 6 and 47 g of antioxidant 1010 were added and mixed at 70 °C for 60 min. The mixture was then added to a twin-screw extruder and melt-blended at the temperatures of 1-6 sections at 180 °C, 210 °C, 230 °C, 235 °C, 235 °C and 225 °C. The mixture was extruded and injection molded in an injection molding machine at the temperatures of 1-4 sections at 220 °C, 230 °C, 230 °C and 225 °C to obtain a polypropylene composite material.
[0036] Comparative Example 4
[0037] (1) Add 40 mmol of ethylene glycol diglycidyl ether and 40 mmol of N,N'-dimethylethylenediamine to 150 mL of tetrahydrofuran, heat to 60°C, stir and react for 10 h, distill under reduced pressure, wash with ethanol, and dry to obtain a hydroxy polymer.
[0038] (2) In an ice bath, 20 g of hydroxy polymer, 0.45 g of triethylamine, and 0.4 g of methacryloyl chloride were added to 250 mL of N,N-dimethylformamide, and then stirred at room temperature for 4 h. The mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain an acrylate-based polymer.
[0039] (3) 500 g of ethylene-octene copolymer (POE), 20 g of acrylate-based polymer, and 0.35 g of diisopropylbenzene peroxide were mixed and melt-grafted in a torque rheometer at 175 °C for 7 min. The product was added to xylene and heated to reflux. Then, acetone was added. After filtering, the precipitate was extracted with acetone and dried to obtain modified POE.
[0040] (4) Add 0.8 kg modified POE and 0.5 kg ultrafine calcium carbonate into a mixer and blend at 80 °C for 2 h. Then add 10 kg polypropylene, 1.5 kg nylon 6 and 47 g antioxidant 1010 and mix at 70 °C for 60 min. Then add the blend into a twin-screw extruder and melt blend at the temperatures of 1-6 sections at 180 °C, 210 °C, 230 °C, 235 °C, 235 °C and 225 °C. Extrude and injection mold in an injection molding machine at the temperatures of 1-4 sections at 220 °C, 230 °C, 230 °C and 225 °C to obtain a polypropylene composite material.
[0041] Example 2
[0042] (1) In an ice bath, add 30 mmol N-Boc-N-methylethylenediamine, 30 mmol triethylamine, and 15 mmol adipoyl chloride to 50 mL of dichloromethane, and then stir and react for 6 h at room temperature. Distill under reduced pressure, wash with water, and then dry. Add the product to 80 mL of 3 mol / L hydrogen chloride in ethyl acetate solution, stir and react for 4 h at room temperature to remove the Boc protecting group. Distill under reduced pressure, wash with saturated sodium carbonate solution, and dry to obtain a diimino monomer.
[0043] (2) Add 40 mmol of ethylene glycol diglycidyl ether and 44 mmol of diimino monomer to 150 mL of tetrahydrofuran, heat to 60°C, stir and react for 8 hours, distill under reduced pressure, wash with ethanol, and dry to obtain a hydroxyl polymer.
[0044] (3) In an ice bath, 20 g of hydroxy polymer, 0.52 g of triethylamine, and 0.46 g of acryloyl chloride were added to 300 mL of N,N-dimethylformamide, and the mixture was stirred at room temperature for 6 h. The mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain an acrylate-based polymer.
[0045] (4) 500 g of ethylene-octene copolymer (POE), 35 g of acrylate-based polymer, and 0.62 g of diisopropylbenzene peroxide were mixed and melt-grafted in a torque rheometer at 180 °C for 7 min. The product was added to xylene and heated to reflux. Then, acetone was added. After filtering, the precipitate was extracted with acetone and dried to obtain modified POE.
[0046] (5) 1.2 kg modified POE and 1.8 kg ultrafine calcium carbonate were added to a mixer and blended at 75 °C for 3 h. Then, 10 kg polypropylene, 2.3 kg nylon 6 and 40 g antioxidant 1010 were added and mixed at 80 °C for 40 min. The mixture was then added to a twin-screw extruder and melt-blended at the temperatures of 1-6 sections at 180 °C, 210 °C, 230 °C, 235 °C, 235 °C and 225 °C. The mixture was extruded and injection molded in an injection molding machine at the temperatures of 1-4 sections at 220 °C, 230 °C, 230 °C and 225 °C to obtain a polypropylene composite material.
[0047] Example 3
[0048] (1) In an ice bath, add 33 mmol N-Boc-N-methylethylenediamine, 33 mmol triethylamine, and 15 mmol glutaryl chloride to 50 mL dichloromethane, and then stir and react at room temperature for 6 h. Distill under reduced pressure, wash with water, and then dry. Add the product to 70 mL of 3 mol / L hydrogen chloride in ethyl acetate solution, stir and react at room temperature for 5 h to remove the Boc protecting group. Distill under reduced pressure, wash with saturated sodium carbonate solution, and dry to obtain a diimino monomer.
[0049] (2) Add 40 mmol of ethylene glycol diglycidyl ether and 40 mmol of diimino monomer to 150 mL of tetrahydrofuran, heat to 50 °C, stir and react for 12 h, distill under reduced pressure, wash with ethanol, and dry to obtain a hydroxyl polymer.
[0050] (3) In an ice bath, 20 g of hydroxy polymer, 0.34 g of triethylamine, and 0.3 g of methacryloyl chloride were added to 250 mL of N,N-dimethylformamide, and the mixture was stirred at room temperature for 4 h. The mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain an acrylate-based polymer.
[0051] (4) 500 g of ethylene-octene copolymer (POE), 50 g of acrylate-based polymer, and 0.9 g of diisopropylbenzene peroxide were mixed and melt-grafted in a torque rheometer at 170 °C for 10 min. The product was added to xylene and heated to reflux. Then, acetone was added. After filtering, the precipitate was extracted with acetone and dried to obtain modified POE.
[0052] (5) 1.5 kg modified POE and 2.5 kg ultrafine calcium carbonate were added to a mixer and blended at 90 °C for 2 h. Then, 10 kg polypropylene, 3 kg nylon 6, and 60 g antioxidant 1010 were added and mixed at 70 °C for 60 min. The mixture was then added to a twin-screw extruder and melt-blended at sections 1-6 at temperatures of 180 °C, 210 °C, 230 °C, 235 °C, 235 °C, and 225 °C. The mixture was extruded and injection molded in an injection molding machine at sections 1-4 at temperatures of 220 °C, 230 °C, 230 °C, and 225 °C to obtain a polypropylene composite material.
[0053] Tensile properties are tested according to GB / T 1040.1-2018. Impact strength is tested according to GB / T 1043.1-2008. Flexural strength is tested according to GB / T 9341-2000.
[0054] Table 1 Mechanical properties test of polypropylene composite materials
[0055] Tensile strength (MPa) Elongation at break (%) <![CDATA[Impact strength (kJ / m 2 )]]> Flexural strength (MPa) Example 1 35.1 472.6 16.4 50.6 Comparative Example 1 32.4 372.0 8.1 41.7 Comparative Example 2 30.3 403.9 10.8 44.3 Comparative Example 3 36.8 442.1 13.5 48.2 Comparative Example 4 31.9 453.8 11.9 47.8 Example 2 42.0 626.7 31.5 64.4 Example 3 31.3 605.6 33.8 57.0
[0056] Compared with Comparative Example 1, Example 1 adds modified POE, and the polymer molecular chain introduced by its side chain grafting contains groups such as hydroxyl, ether bond and amide bond, and hydroxyl and ether bond can form hydrogen bonds, chemical bonds and other interactions with the hydroxyl surface of ultrafine calcium carbonate, thereby realizing the surface modification and modification of ultrafine calcium carbonate by POE, and POE contains a large number of amide bonds, and has similar polarity to the polyamide molecular chain of nylon 6, so that modified POE has good similar compatibility with nylon 6, and modified POE contains a polyolefin backbone, and has high compatibility with polypropylene, so that modified POE can be used as a compatibilizer, while improving the compatibility between ultrafine calcium carbonate, nylon 6 and polypropylene, so that polypropylene and nylon 6 form a compatible alloy system, ultrafine calcium carbonate strength better reinforcement, and modified POE also plays a good toughening effect, and the obtained polypropylene composite material shows higher tensile properties, impact strength and flexural strength. Example 2-3 regulates the ratio of raw materials, and the obtained polypropylene material also has good mechanical properties.
[0057] In Comparative Example 2, only ethylene-octene copolymer POE was added, which failed to act as a compatibilizer and could not improve the compatibility between ultrafine calcium carbonate, nylon 6 and polypropylene, resulting in poor mechanical properties such as tensile strength of the polypropylene composite material.
[0058] In Comparative Example 3, maleic anhydride-grafted POE is added. The anhydride groups contained in the maleic anhydride can react with ultrafine calcium carbonate and the terminal amino group of nylon 6 to improve the compatibility between the two and polypropylene. The tensile strength and other mechanical properties of the polypropylene material are significantly higher than those of Comparative Example 1, but its elongation at break and impact strength are significantly lower than those of Example 1. This may be because the side chain of the modified POE in Example 1 introduces a flexible polyether molecular chain, which has a better toughening effect, is conducive to improving toughness, and exhibits higher elongation at break and impact strength.
[0059] In Comparative Example 4, N,N'-dimethylethylenediamine is used as a reactant, and the molecular chains of the prepared hydroxyl polymer and acrylate-based polymer do not contain amide bonds. After melt grafting of POE, the side chains of the modified POE obtained do not contain amide bonds, and the compatibility with nylon 6 is poor. It is impossible to improve the compatibility between nylon 6 and polypropylene, and no compatible alloy system is formed, resulting in low mechanical properties such as tensile strength of the composite material.
[0060] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A polypropylene composite material, characterized in that The raw materials include, by weight, 100 parts of polypropylene, 15-30 parts of nylon 6, 5-25 parts of ultrafine calcium carbonate, 8-15 parts of modified POE, and 0.4-0.6 parts of antioxidant; The preparation method of the modified POE is: (1) Add ethylene glycol diglycidyl ether, structural formula: A diimino monomer, wherein a is any integer from 2 to 4, is heated to the reaction temperature, stirred for reaction, distilled under reduced pressure, washed with ethanol, and dried to obtain a hydroxyl polymer; (2) Adding hydroxy polymer, triethylamine and acryloyl chloride monomer to N,N-dimethylformamide in an ice bath, stirring and reacting at room temperature for 4-6 hours, distilling under reduced pressure, washing with ethanol, and drying to obtain an acrylate-based polymer; (3) Ethylene-octene copolymer POE, acrylate-based polymer, and diisopropylbenzene peroxide are mixed and melt grafted in a torque rheometer. The product is added to xylene and heated to reflux. Then, acetone is added. After filtering, the precipitate is extracted with acetone and dried to obtain modified POE.
2. The polypropylene composite material according to claim 1, characterized in that The reaction temperature in (1) is 50-60°C, and the reaction time is 8-12h.
3. The polypropylene composite material according to claim 1, characterized in that The molar ratio of ethylene glycol diglycidyl ether to diimino monomer in (1) is 1:(1-1.1).
4. The polypropylene composite material according to claim 3, characterized in that The preparation method of the diimino monomer comprises: adding N-Boc-N-methylethylenediamine, triethylamine, and diacyl chloride in a molar ratio of (2-2.2):(2-2.2):1 to dichloromethane in an ice bath, stirring and reacting at room temperature for 6-8 hours, distilling under reduced pressure, washing with water, and then drying; adding the product to an ethyl acetate solution of hydrogen chloride, stirring and reacting at room temperature for 4-5 hours, distilling under reduced pressure, washing with a saturated sodium carbonate solution, and drying to obtain the diimino monomer.
5. The polypropylene composite material according to claim 4, characterized in that The structural formula of the diacyl chloride is , a is any integer between 2 and 4.
6. The polypropylene composite material according to claim 1, characterized in that The mass ratio of the hydroxy polymer, triethylamine and acryloyl chloride monomer in (2) is 100:(1.7-2.6):(1.5-2.3); the acryloyl chloride monomer is acryloyl chloride or methacryloyl chloride.
7. The polypropylene composite material according to claim 1, characterized in that The mass ratio of ethylene-octene copolymer POE, acrylate-based polymer and dicumyl peroxide in (3) is 100:(4-10):(0.07-0.18).
8. The polypropylene composite material according to claim 1, characterized in that The temperature during the melt grafting in (3) is 170-180°C and the time is 7-10 minutes.
9. A method for preparing the polypropylene composite material according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: adding modified POE and ultrafine calcium carbonate into a mixer, blending at 75-90° C. for 2-3 hours, then adding polypropylene, nylon 6, and an antioxidant, mixing at 70-80° C. for 40-60 minutes, adding the blend into a twin-screw extruder, melt-blending at 180-235° C., extruding, and injection molding in an injection molding machine at 220-230° C. to obtain a polypropylene composite material.
10. Use of the polypropylene composite material obtained by the preparation method according to claim 9 in the preparation of a self-balancing vehicle.