A polypropylene material for automobile and its preparation method

Abstract

This invention relates to the field of polymer materials technology, specifically to a collision-resistant polypropylene material for automobiles and its preparation method, comprising the following raw materials in parts by weight: 65-75 parts polypropylene, 15-20 parts composite additives, 8-12 parts long glass fibers, 0.8-1.2 parts coupling agent, 0.4-0.6 parts antioxidant, and 0.3-0.5 parts light stabilizer. In this invention, the composite additives form a highly efficient collision-resistant system, which, combined with the long glass fibers, constitutes an impact-resistant network. This effectively disperses collision stress, improves the material's rigidity and deformation resistance, inhibits crack propagation, and enhances the material's resistance to external impacts.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a collision-resistant polypropylene material for automobiles and its preparation method. Background Technology

[0002] With the rapid development of the automotive industry, lightweighting and safety have become the core trends in the industry. Polypropylene, due to its low density, low cost, good processing fluidity, and excellent chemical stability, is widely used in the production and manufacturing of automotive parts, accounting for more than 30% of the plastics used in automobiles, and is one of the key materials for achieving lightweighting of automobiles.

[0003] In existing technologies, ordinary polypropylene materials have an inherent defect of insufficient resistance to external impacts. Especially in the event of a collision during vehicle operation, they are prone to brittleness and deformation, failing to meet the stringent requirements for impact resistance of critical automotive safety components. Therefore, this invention provides an impact-resistant polypropylene material for automobiles and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a collision-resistant polypropylene material for automobiles and its preparation method. The collision-resistant polypropylene material for automobiles prepared by this invention has good collision resistance and effectively improves the performance of polypropylene materials for automobiles.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a polypropylene material for automobiles that is resistant to external impact, comprising the following raw materials in parts by weight: 65-75 parts of polypropylene, 15-20 parts of composite additives, 8-12 parts of long glass fibers, 0.8-1.2 parts of coupling agent, 0.4-0.6 parts of antioxidant, and 0.3-0.5 parts of light stabilizer.

[0006] Furthermore, the polypropylene is impact copolymer polypropylene K8003.

[0007] Furthermore, the composite additive includes additives, magnesium borate whiskers, thermoplastic polyimide micro powder, and polyetheretherketone micro powder, and the magnesium borate whiskers are pretreated before preparing the composite additive.

[0008] Furthermore, the additive comprises a composite and aluminum nitride powder.

[0009] Further, the preparation method of the composite additive is as follows: the additive, thermoplastic polyimide micro powder, polyetheretherketone micro powder, and magnesium borate whiskers are added to a high-speed mixer in a mass ratio of (2.5-3.5):(2.5-3.5):1:(3.5-4.5), then butyl acetate solvent is added, and the mixture is ultrasonically dispersed at 20-30℃ and 200-300W for 25-35 minutes, followed by magnetic stirring at 800-1000rpm for 1 hour, and then stirred for 60-7 minutes. The mixture is stirred at 0℃ and 1000-1200rpm for 30-40 minutes. After stirring, it is cooled to room temperature and dried under vacuum at 55-65℃ and 0.09MPa for 3.5-4.5 hours. Finally, it is pulverized to 75-100μm to obtain the composite additive. The thermoplastic polyimide micro powder has a particle size of 50-100μm, the polyetheretherketone micro powder has a particle size of 25-45μm, and the mass of butyl acetate solvent is 80-100% of the mass of the additive.

[0010] Further, the preparation method of the additive is as follows: the composite and aluminum nitride powder are added to toluene solvent at a mass ratio of (6-8):(2-4), then a catalyst is added, and the mixture is stirred at 70-80℃ and 600-800rpm for 3-5h. Subsequently, it is ultrasonically dispersed at 200-300W for 20-30min, and vacuum dried at 65-75℃ and 0.09MPa for 2.5-3.5h to obtain the additive. The particle size of the aluminum nitride powder is 50-100nm, the mass of the toluene solvent is 70-90% of the total mass of the composite and aluminum nitride powder, and the catalyst is triethylamine, the mass of which is 1-2% of the total mass of the composite and aluminum nitride powder.

[0011] Further, the pretreatment method for the magnesium borate whiskers is as follows: Magnesium borate whiskers are added to a 5% (w / w) ethanol solution of silane coupling agent KH-570 at a mass-to-volume ratio of 1:(9-11). The mixture is stirred and refluxed at 70-80°C and 500-700 rpm for 2-3 hours. After filtering off the liquid, the filter residue is dried at 100-110°C for 2-3 hours to obtain pretreated magnesium borate whiskers. The pretreated magnesium borate whiskers are then mixed with lanthanum oxide at a mass ratio of 1:(9-11). 00: (1-2) Mix, then add deionized water, ultrasonically disperse at 200-300W for 30min, then dry at 100-110℃ for 2.5-3.5h, then calcine in a muffle furnace at 350-450℃ for 1-2h, and after cooling, obtain pretreated magnesium borate whiskers, wherein the particle size of magnesium borate whiskers is 5-10μm, and the volume of deionized water is 80-100% of the total mass of the pretreated magnesium borate whiskers and lanthanum oxide.

[0012] Further, the preparation method of the composite is as follows: hydroxyl-terminated polybutadiene and maleic anhydride are added to toluene solvent at a mass ratio of 100:(7-9), an initiator is added, and the mixture is refluxed at 85-95℃ for 5-7 hours. After the reaction is completed, the mixture is distilled under reduced pressure at 0.08-0.10 MPa and 80-90℃. The remaining solid is dried at 90-100℃ for 2-3 hours to obtain the composite. The volume of the toluene solvent is 100-120% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride, and the initiator is benzoyl peroxide, with a mass of 1.5-2.5% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride.

[0013] Furthermore, the long glass fiber is an alkali-free long glass fiber with a length of 3-8 mm. Before preparing the automotive impact-resistant polypropylene material, it is soaked in silane coupling agent KH-570 for 30-60 minutes and dried at 90°C to constant weight for later use.

[0014] Furthermore, the coupling agent is a mixture of KH-550 and DL-411 in a weight ratio of 2:1.

[0015] Furthermore, the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1.

[0016] Furthermore, the light stabilizer is a mixture of light stabilizer HALS and light stabilizer UV-327 in a mass ratio of 3:2.

[0017] Secondly, this invention provides a method for preparing a collision-resistant polypropylene material for automobiles, comprising the following steps: (1) Add polypropylene, composite additives, coupling agent, antioxidant and light stabilizer into a high-speed mixer, stir at 800-1000 rpm for 5-8 min at 20-25℃, then heat to 100-110℃ at a rate of 5-8℃ / min, and continue stirring for 10-15 min to obtain premixed powder. (2) Add the premixed powder to the main feed of the twin-screw extruder. Add the pretreated long glass fiber from the side feed port of the extruder. Control the temperature of the extruder feed section to 160-170℃, the temperature of the compression section to 170-185℃, the temperature of the homogenization section to 185-195℃, the temperature of the die head section to 180-190℃, and the screw speed to 120-180rpm. After extrusion, the material is cooled by water at 20-30℃ and granulated to a particle size of 2-4mm. Then, it is dried at 70-80℃ for 1-2 hours to obtain polypropylene granules. (3) Place the polypropylene granules into an injection molding machine. The injection temperature is 180-200℃, the injection pressure is 80-100MPa, the holding pressure is 60-80MPa, and after cooling, you will get a polypropylene material for automobiles that is resistant to external impact.

[0018] Compared with the prior art, the beneficial effects of the present invention are: In this invention, a highly efficient anti-collision system is formed through composite additives. The composite material in the additives preferentially absorbs collision kinetic energy due to its excellent elastic deformation characteristics. Nanoscale aluminum nitride powder fills the gaps in the polypropylene matrix and improves interfacial bonding defects. Pretreated magnesium borate whiskers are grafted with silane coupling agent and modified with lanthanum oxide to form a reinforcing structure. The high rigidity of thermoplastic polyimide micropowder and the high impact resistance of polyether ether ketone micropowder work synergistically. Combined with long glass fibers, they form an anti-collision network that can effectively disperse collision stress, improve the rigidity and deformation resistance of the material, inhibit crack propagation, and enhance the material's resistance to external impact. Attached Figure Description

[0019] Figure 1 The present invention provides a flowchart of a collision-resistant polypropylene material for automobiles and its preparation method. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0022] Example 1: Prepare the following raw materials by weight: 65 parts polypropylene, 15 parts composite additive, 8 parts long glass fiber, 0.8 parts coupling agent, 0.4 parts antioxidant, and 0.3 parts light stabilizer. The long glass fiber is alkali-free long glass fiber with a length of 3-8 mm. Before preparing the automotive impact-resistant polypropylene material, it is soaked in silane coupling agent KH-570 for 30 min and dried at 90℃ to constant weight for later use.

[0023] (I) Preparation of the composite: Hydroxyl-terminated polybutadiene and maleic anhydride were added to toluene solvent at a mass ratio of 100:7. An initiator was added, and the mixture was refluxed at 85°C for 5 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.08 MPa and 80°C. The remaining solid was dried at 90°C for 2 hours to obtain the composite. The volume of the toluene solvent was 100% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride. The initiator was benzoyl peroxide, and the mass of the initiator was 1.5% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride.

[0024] (II) Preparation of additives: The composite and aluminum nitride powder were added to toluene solvent at a mass ratio of 6:4, and then the catalyst was added. The mixture was stirred at 70°C and 600 rpm for 3 h, followed by ultrasonic dispersion at 200 W for 20 min, and vacuum drying at 65°C and 0.09 MPa for 2.5 h to obtain the additives. The particle size of the aluminum nitride powder was 50-100 nm, the mass of the toluene solvent was 70% of the total mass of the composite and aluminum nitride powder, and the catalyst was triethylamine, with the mass of the catalyst being 1% of the total mass of the composite and aluminum nitride powder.

[0025] (III) Pretreatment of magnesium borate whiskers: Magnesium borate whiskers were added to a 5% (w / w) ethanol solution of silane coupling agent KH-570 at a mass-volume ratio of 1:9. The mixture was stirred and refluxed at 70°C and 500 rpm for 2 h. After filtering out the liquid, the filter residue was dried at 100°C for 2 h to obtain pretreated magnesium borate whiskers. The pretreated magnesium borate whiskers were mixed with lanthanum oxide at a mass ratio of 100:1, and then deionized water was added. The mixture was ultrasonically dispersed at 200 W for 30 min, and then dried at 100°C for 2.5 h. The mixture was then calcined in a muffle furnace at 350°C for 1 h. After cooling, pretreated magnesium borate whiskers were obtained. The particle size of the magnesium borate whiskers was 5-10 μm, and the volume of deionized water was 80% of the total mass of the pretreated magnesium borate whiskers and lanthanum oxide.

[0026] (iv) Preparation of composite additive: Add the additive, thermoplastic polyimide micro powder, polyetheretherketone micro powder, and magnesium borate whiskers in a mass ratio of 2.5:2.5:1:3.5 into a high-speed mixer, then add butyl acetate solvent, ultrasonically disperse at 20°C and 200W for 25 min, then magnetically stir at 800 rpm for 1 h, followed by low-temperature stirring at 60°C and 1000 rpm for 30 min. After stirring, cool to room temperature, vacuum dry at 55°C and 0.09 MPa for 3.5 h, and finally pulverize to 75-100 μm to obtain the composite additive, wherein the thermoplastic polyimide micro powder has a particle size of 50-100 μm, the polyetheretherketone micro powder has a particle size of 25-45 μm, and the mass of butyl acetate solvent is 80% of the mass of the additive.

[0027] (v) Preparation of automotive impact-resistant polypropylene materials: (1) Add polypropylene, composite additives, coupling agent, antioxidant and light stabilizer to a high-speed mixer, stir at 800 rpm for 5 min at 20℃, then heat to 100℃ at a rate of 5℃ / min, and continue stirring for 10 min to obtain premixed powder. (2) Add the premixed powder to the main feed of the twin-screw extruder. The pretreated long glass fiber is added from the side feed port of the extruder. Control the temperature of the extruder feed section to 160℃, the temperature of the compression section to 170℃, the temperature of the homogenization section to 185℃, the temperature of the die head section to 180℃, and the screw speed to 120rpm. After extrusion, the material is cooled by water at 20℃, granulated, and the particle size is 2mm. Then, it is dried at 70℃ for 1h to obtain polypropylene granules. (3) The polypropylene granules are placed in the injection molding machine. The injection temperature is 180℃, the injection pressure is 80MPa, the holding pressure is 60MPa, and after cooling, the automotive-grade polypropylene material resistant to external impact is obtained.

[0028] Example 2: Prepare the following raw materials by weight: 70 parts polypropylene, 18 parts composite additives, 10 parts long glass fibers, 1 part coupling agent, 0.5 parts antioxidant, and 0.4 parts light stabilizer. The long glass fibers are alkali-free long glass fibers with a length of 3-8 mm. Before preparing the automotive impact-resistant polypropylene material, soak it in silane coupling agent KH-570 for 45 min and dry it at 90℃ to constant weight for later use.

[0029] (I) Preparation of the composite: Hydroxyl-terminated polybutadiene and maleic anhydride were added to toluene solvent at a mass ratio of 100:8. An initiator was added, and the mixture was refluxed at 90°C for 6 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.09 MPa and 85°C. The remaining solid was dried at 95°C for 2.5 hours to obtain the composite. The volume of the toluene solvent was 110% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride, and the initiator was benzoyl peroxide, with a mass of 2% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride.

[0030] (II) Preparation of additives: The composite and aluminum nitride powder were added to toluene solvent at a mass ratio of 7:3, and then the catalyst was added. The mixture was stirred at 700 rpm for 4 h at 75 °C, then ultrasonically dispersed at 250 W for 25 min, and vacuum dried at 0.09 MPa for 3 h to obtain the additives. The particle size of the aluminum nitride powder was 50-100 nm, the mass of the toluene solvent was 80% of the total mass of the composite and aluminum nitride powder, and the catalyst was triethylamine, the mass of which was 1.5% of the total mass of the composite and aluminum nitride powder.

[0031] (III) Pretreatment of magnesium borate whiskers: Magnesium borate whiskers were added to a 5% (w / w) ethanol solution of silane coupling agent KH-570 at a mass-volume ratio of 1:10. The mixture was stirred and refluxed at 75°C and 600 rpm for 2.5 h. After filtering out the liquid, the filter residue was dried at 105°C for 2.5 h to obtain pretreated magnesium borate whiskers. The pretreated magnesium borate whiskers were mixed with lanthanum oxide at a mass ratio of 100:1.5. Deionized water was added, and the mixture was ultrasonically dispersed at 250 W for 30 min. The mixture was then dried at 105°C for 3 h and calcined in a muffle furnace at 400°C for 1.5 h. After cooling, pretreated magnesium borate whiskers were obtained. The particle size of the magnesium borate whiskers was 5-10 μm, and the volume of deionized water was 90% of the total mass of the pretreated magnesium borate whiskers and lanthanum oxide.

[0032] (iv) Preparation of composite additive: Add the additive, thermoplastic polyimide micro powder, polyetheretherketone micro powder, and magnesium borate whiskers in a mass ratio of 3:3:1:4 to a high-speed mixer, then add butyl acetate solvent, ultrasonically disperse at 25°C and 250W for 30 min, then magnetically stir at 900 rpm for 1 h, followed by low-temperature stirring at 65°C and 1100 rpm for 35 min. After stirring, cool to room temperature, vacuum dry at 60°C and 0.09 MPa for 4 h, and finally pulverize to 75-100 μm to obtain the composite additive, wherein the thermoplastic polyimide micro powder has a particle size of 50-100 μm, the polyetheretherketone micro powder has a particle size of 25-45 μm, and the mass of butyl acetate solvent is 90% of the mass of the additive.

[0033] (v) Preparation of automotive impact-resistant polypropylene materials: (1) Add polypropylene, composite additives, coupling agent, antioxidant and light stabilizer into a high-speed mixer, stir at 900 rpm for 6 min at 22℃, then heat to 105℃ at a rate of 6℃ / min, and continue stirring for 12 min to obtain premixed powder. (2) Add the premixed powder to the main feed of the twin-screw extruder. The pretreated long glass fiber is added from the side feed port of the extruder. Control the temperature of the extruder feed section to 165℃, the temperature of the compression section to 175℃, the temperature of the homogenization section to 190℃, the temperature of the die head section to 185℃, and the screw speed to 150rpm. After extrusion, the material is cooled by water at 25℃, granulated, and the particle size is 3mm. Then, it is dried at 75℃ for 1.5h to obtain polypropylene granules. (3) The polypropylene granules are placed in the injection molding machine. The injection temperature is 190℃, the injection pressure is 90MPa, the holding pressure is 70MPa, and after cooling, the automotive-grade polypropylene material resistant to external impact is obtained.

[0034] Example 3: Prepare the following raw materials by weight: 75 parts polypropylene, 20 parts composite additive, 12 parts long glass fiber, 1.2 parts coupling agent, 0.6 parts antioxidant, and 0.5 parts light stabilizer. The long glass fiber is alkali-free long glass fiber with a length of 3-8 mm. Before preparing the automotive impact-resistant polypropylene material, it is soaked in silane coupling agent KH-570 for 60 min and dried at 90℃ to constant weight for later use.

[0035] (I) Preparation of the composite: Hydroxyl-terminated polybutadiene and maleic anhydride were added to toluene solvent at a mass ratio of 100:9. An initiator was added, and the mixture was refluxed at 95°C for 7 hours. After the reaction was completed, the mixture was distilled under reduced pressure at 0.10 MPa and 90°C. The remaining solid was dried at 100°C for 3 hours to obtain the composite. The volume of the toluene solvent was 120% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride. The initiator was benzoyl peroxide, and the mass of the initiator was 2.5% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride.

[0036] (II) Preparation of additives: The composite and aluminum nitride powder were added to toluene solvent at a mass ratio of 8:2, and then the catalyst was added. The mixture was stirred at 800 rpm for 5 h at 80 °C, then ultrasonically dispersed at 300 W for 30 min, and vacuum dried at 75 °C and 0.09 MPa for 3.5 h to obtain the additives. The particle size of the aluminum nitride powder was 50-100 nm, the mass of the toluene solvent was 90% of the total mass of the composite and aluminum nitride powder, and the catalyst was triethylamine, which accounted for 2% of the total mass of the composite and aluminum nitride powder.

[0037] (III) Pretreatment of magnesium borate whiskers: Magnesium borate whiskers were added to a 5% (w / w) ethanol solution of silane coupling agent KH-570 at a mass-volume ratio of 1:11. The mixture was stirred and refluxed at 700 rpm for 3 h at 80 °C. After filtering out the liquid, the filter residue was dried at 110 °C for 3 h to obtain pretreated magnesium borate whiskers. The pretreated magnesium borate whiskers were mixed with lanthanum oxide at a mass ratio of 100:2. Deionized water was added, and the mixture was ultrasonically dispersed at 300 W for 30 min. The mixture was then dried at 110 °C for 3.5 h and calcined in a muffle furnace at 450 °C for 2 h. After cooling, pretreated magnesium borate whiskers were obtained. The particle size of the magnesium borate whiskers was 5-10 μm, and the volume of deionized water was 100% of the total mass of the pretreated magnesium borate whiskers and lanthanum oxide.

[0038] (iv) Preparation of composite additive: Add the additive, thermoplastic polyimide micro powder, polyetheretherketone micro powder, and magnesium borate whiskers in a mass ratio of 3.5:3.5:1:4.5 to a high-speed mixer, then add butyl acetate solvent, ultrasonically disperse at 30°C and 300W for 35 min, then magnetically stir at 1000 rpm for 1 h, followed by low-temperature stirring at 70°C and 1200 rpm for 40 min. After stirring, cool to room temperature, vacuum dry at 65°C and 0.09 MPa for 4.5 h, and finally pulverize to 75-100 μm to obtain the composite additive, wherein the thermoplastic polyimide micro powder has a particle size of 50-100 μm, the polyetheretherketone micro powder has a particle size of 25-45 μm, and the mass of butyl acetate solvent is 100% of the mass of the additive.

[0039] (v) Preparation of automotive impact-resistant polypropylene materials: (1) Add polypropylene, composite additives, coupling agent, antioxidant and light stabilizer into a high-speed mixer, stir at 1000 rpm for 8 min at 25℃, then heat to 110℃ at a rate of 8℃ / min, and continue stirring for 15 min to obtain premixed powder. (2) Add the premixed powder to the main feed of the twin-screw extruder. The pretreated long glass fiber is added from the side feed port of the extruder. Control the temperature of the extruder feed section to 170℃, the temperature of the compression section to 185℃, the temperature of the homogenization section to 195℃, the temperature of the die head section to 190℃, and the screw speed to 180rpm. After extrusion, the material is cooled by water at 30℃, granulated, and the particle size is 4mm. Then, it is dried at 80℃ for 2h to obtain polypropylene granules. (3) The polypropylene granules are placed in the injection molding machine. The injection temperature is 200℃, the injection pressure is 100MPa, the holding pressure is 80MPa, and after cooling, the automotive-grade polypropylene material resistant to external impact is obtained.

[0040] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain composite additives.

[0041] Comparative Example 2: The difference between this comparative example and Example 1 is that no additives were added when preparing the composite additive in this comparative example.

[0042] Comparative Example 3: The difference between this comparative example and Example 1 is that the magnesium borate whiskers in this comparative example are not pretreated.

[0043] Performance testing: The automotive impact-resistant polypropylene materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the test data are recorded in the table below: Table 1

[0044] In the performance test, the impact resistance test was conducted in accordance with GB / T 1843-2008. The test was conducted on the notched impact strength of the cantilever beam. The higher the notched impact strength of the cantilever beam, the better the impact resistance and the more resistant the material is to external impact.

[0045] Among them, the cantilever beam notched impact strength test results of the automotive impact-resistant polypropylene materials prepared in Examples 1-3 and Comparative Examples 1-3 were 35.3 kJ / m. 2 39.6 kJ / m 2 36.8kJ / m 2 10.7 kJ / m 2 18.2kJ / m 2 26.9kJ / m 2 .

[0046] It is evident that the notched impact strength of the cantilever beam of the automotive impact-resistant polypropylene material prepared in Comparative Examples 1-3 is lower than that in Examples 1-3. This indicates that in Examples 1-3, the composite additive serves as the core impact-resistant modification component. The additive preferentially absorbs impact energy due to the high elastic deformation capacity of the composite. Nano-aluminum nitride powder fills the gaps in the polypropylene matrix and improves interface defects, thereby enhancing the interfacial bonding strength. Magnesium borate whiskers, after being grafted with a silane coupling agent and doped with rare earth lanthanum oxide, form a rigid support structure, effectively dispersing stress, inhibiting crack generation and propagation, and improving the structural stability of the material under dynamic stress. Thermoplastic polyimide micropowder and polyetheretherketone micropowder have good impact resistance, further enhancing the material's resistance to deformation under complex stress environments. Combined with long glass fibers, the overall structural strength is further enhanced, giving the material superior impact resistance under impact loads. Comparative Example 1 did not add composite additives, and the material lacked a reinforcement and toughening system, resulting in a significant decrease in impact resistance. Comparative Example 2 lacked additives, resulting in insufficient toughness and interfacial bonding, and a decrease in the material's impact strength. Comparative Example 3 did not use pretreated magnesium borate whiskers, resulting in weak reinforcement, poor stability, lower impact strength, and inferior impact resistance compared to the examples.

[0047] By comparing and analyzing the relevant data in the table, it can be seen that the automotive impact-resistant polypropylene material prepared by this invention has good impact resistance. This indicates that the automotive impact-resistant polypropylene material provided by this invention has a broader market prospect and is more suitable for widespread application.

[0048] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A type of automotive impact-resistant polypropylene material, characterized in that, The raw materials include the following parts by weight: 65-75 parts polypropylene, 15-20 parts composite additives, 8-12 parts long glass fibers, 0.8-1.2 parts coupling agent, 0.4-0.6 parts antioxidant, and 0.3-0.5 parts light stabilizer; The polypropylene is an impact-resistant copolymer polypropylene; The composite additive includes additives, magnesium borate whiskers, thermoplastic polyimide micro powder, and polyetheretherketone micro powder, and the magnesium borate whiskers are pretreated before the composite additive is prepared. The additives comprise a complex and aluminum nitride powder.

2. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The preparation method of the composite additive is as follows: Add the additive, thermoplastic polyimide micro powder, polyetheretherketone micro powder, and magnesium borate whiskers to a high-speed mixer at a mass ratio of (2.5-3.5):(2.5-3.5):1:(3.5-4.5), then add butyl acetate solvent, and ultrasonically disperse at 20-30℃ and 200-300W for 25-35 minutes, followed by magnetic stirring at 800-1000rpm for 1 hour, and then at 60-70℃... Stir at 1000-1200 rpm at low temperature for 30-40 min. After stirring, cool to room temperature and dry under vacuum at 55-65℃ and 0.09 MPa for 3.5-4.5 h. Finally, pulverize to 75-100 μm to obtain the composite additive. The thermoplastic polyimide micro powder has a particle size of 50-100 μm, the polyetheretherketone micro powder has a particle size of 25-45 μm, and the mass of butyl acetate solvent is 80-100% of the mass of the additive.

3. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The preparation method of the additive is as follows: the composite and aluminum nitride powder are added to toluene solvent at a mass ratio of (6-8):(2-4), and then a catalyst is added. The mixture is stirred at 70-80℃ and 600-800rpm for 3-5h, followed by ultrasonic dispersion at 200-300W for 20-30min, and vacuum dried at 65-75℃ and 0.09MPa for 2.5-3.5h to obtain the additive. The particle size of the aluminum nitride powder is 50-100nm, the mass of the toluene solvent is 70-90% of the total mass of the composite and aluminum nitride powder, and the catalyst is triethylamine, the mass of which is 1-2% of the total mass of the composite and aluminum nitride powder.

4. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The pretreatment method for the magnesium borate whiskers is as follows: Magnesium borate whiskers are added to a 5% (w / w) ethanol solution of silane coupling agent KH-570 at a mass-to-volume ratio of 1:(9-11). The mixture is stirred and refluxed at 70-80°C and 500-700 rpm for 2-3 hours. After filtering off the liquid, the filter residue is dried at 100-110°C for 2-3 hours to obtain pretreated magnesium borate whiskers. The pretreated magnesium borate whiskers are then mixed with lanthanum oxide at a mass ratio of 100:

1. (1-2) Mix, then add deionized water, ultrasonically disperse at 200-300W for 30min, then dry at 100-110℃ for 2.5-3.5h, then calcine in a muffle furnace at 350-450℃ for 1-2h, and after cooling, obtain pretreated magnesium borate whiskers, wherein the particle size of magnesium borate whiskers is 5-10μm, and the volume of deionized water is 80-100% of the total mass of the pretreated magnesium borate whiskers and lanthanum oxide.

5. The automotive impact-resistant polypropylene material according to claim 3, characterized in that, The composite is prepared as follows: hydroxyl-terminated polybutadiene and maleic anhydride are added to toluene solvent at a mass ratio of 100:(7-9), an initiator is added, and the mixture is refluxed at 85-95℃ for 5-7 hours. After the reaction is completed, the mixture is distilled under reduced pressure at 0.08-0.10 MPa and 80-90℃. The remaining solid is dried at 90-100℃ for 2-3 hours to obtain the composite. The volume of the toluene solvent is 100-120% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride, and the initiator is benzoyl peroxide, with a mass of 1.5-2.5% of the total mass of the hydroxyl-terminated polybutadiene and maleic anhydride.

6. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The long glass fiber is an alkali-free long glass fiber with a length of 3-8 mm. Before preparing the automotive impact-resistant polypropylene material, it is soaked in silane coupling agent KH-570 for 30-60 minutes and dried at 90°C to constant weight for later use.

7. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The coupling agent is a mixture of KH-550 and DL-411 in a weight ratio of 2:

1.

8. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:

1.

9. The automotive impact-resistant polypropylene material according to claim 1, characterized in that, The light stabilizer is a mixture of light stabilizer HALS and light stabilizer UV-327 in a mass ratio of 3:

2.

10. The method for preparing automotive impact-resistant polypropylene material according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Add polypropylene, composite additives, coupling agent, antioxidant and light stabilizer into a high-speed mixer, stir at 800-1000 rpm for 5-8 min at 20-25℃, then heat to 100-110℃ at a rate of 5-8℃ / min, and continue stirring for 10-15 min to obtain premixed powder. (2) Add the premixed powder to the main feed of the twin-screw extruder. Add the pretreated long glass fiber from the side feed port of the extruder. Control the temperature of the extruder feed section to 160-170℃, the temperature of the compression section to 170-185℃, the temperature of the homogenization section to 185-195℃, the temperature of the die head section to 180-190℃, and the screw speed to 120-180rpm. After extrusion, the material is cooled by water at 20-30℃ and granulated to a particle size of 2-4mm. Then, it is dried at 70-80℃ for 1-2 hours to obtain polypropylene granules. (3) Place the polypropylene granules into an injection molding machine. The injection temperature is 180-200℃, the injection pressure is 80-100MPa, the holding pressure is 60-80MPa, and after cooling, you will get a polypropylene material for automobiles that is resistant to external impact.

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