Polyethylene wax modified polypropylene material and preparation method thereof

Abstract

The present invention belongs to the field of high-performance polypropylene technology, and in particular to a polyethylene wax-modified polypropylene material and a preparation method thereof. The present invention aims to solve the problems of poor mechanical properties and poor aging resistance of existing polyethylene wax-polypropylene composite materials. The present invention carries out in-situ polymerization grafting by polyethylene wax raw material to obtain prefabricated polyethylene wax; functional filler and prefabricated polyethylene wax are melt-mixed to obtain modified polyethylene wax; polypropylene resin and modified polyethylene wax are reacted and mixed to obtain modified polypropylene; polyethylene wax raw material is oxidatively modified to obtain main polyethylene wax; main polyethylene wax, cross-linking agent and modified polypropylene are subjected to in-situ reaction extrusion to obtain composite polypropylene; composite polypropylene is subjected to high-temperature solid-phase post-treatment to obtain polyethylene wax-modified polypropylene material. The polyethylene wax-modified polypropylene material prepared by the present invention has both good toughness and mechanical strength, and excellent aging resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of high-performance polypropylene, and particularly relates to a polyethylene wax-modified polypropylene material and a preparation method thereof. Background Art

[0002] Polypropylene is a versatile thermoplastic polymer that is widely used in various industries due to its good chemical resistance, easy processing, and cost-effectiveness. Despite its many advantages, polypropylene has certain shortcomings that limit its wider application. For example, polypropylene has good impact strength but becomes brittle at low temperatures. Compared with polyethylene, polypropylene has limited wear resistance and presents processing performance challenges, such as warping of thick-walled products due to its high shrinkage. In addition, due to its low surface energy, polypropylene has difficulty bonding with adhesives and coatings, and its processing window is also narrower than that of polyethylene. Other disadvantages include poor UV resistance, flammability, and susceptibility to environmental stress cracking.

[0003] Polyethylene wax is a potential polypropylene modifier. Due to its low molecular weight, polyethylene wax exhibits waxy physical properties, including low viscosity, high hardness, and a relatively high melting point, and exhibits good compatibility with polypropylene under certain circumstances. Polypropylene materials modified by polyethylene wax blending can improve processability and tensile strength, and can also introduce rich functionality to high-performance polypropylene materials. However, current research on polyethylene wax-modified polypropylene materials within the industry is still insufficient, and the poor mechanical properties and aging resistance of existing polyethylene wax-polypropylene composites remain challenges that need to be addressed.

[0004] To this end, a polyethylene wax-modified polypropylene material and a preparation method thereof are proposed. Summary of the Invention

[0005] The present invention aims to provide a polyethylene wax-modified polypropylene material and a preparation method thereof. The present invention comprises the following steps: in-situ polymerization and grafting of a polyethylene wax raw material to obtain a prefabricated polyethylene wax; melt-mixing a functional filler with the prefabricated polyethylene wax to obtain a modified polyethylene wax; reacting and mixing a polypropylene resin with the modified polyethylene wax to obtain a modified polypropylene; oxidatively modifying the polyethylene wax raw material to obtain a main polyethylene wax; in-situ reaction extrusion of the main polyethylene wax, a crosslinking agent, and the modified polypropylene to obtain a composite polypropylene; and subjecting the composite polypropylene to a high-temperature solid-phase post-treatment to obtain the polyethylene wax-modified polypropylene material.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a polyethylene wax-modified polypropylene material comprises the following steps:

[0008] Unless otherwise specified, the parts in the present invention refer to parts by mass, and the average molecular weight refers to the number-average molecular weight.

[0009] In-situ polymerization and grafting of polyethylene wax raw materials to obtain prefabricated polyethylene wax;

[0010] The polyethylene wax raw material is high-density polyethylene degradation wax with an average molecular weight of 8000-10000Da and a density of 0.96g / cm 3 .

[0011] The functional filler and the prefabricated polyethylene wax are melt-mixed to obtain a modified polyethylene wax;

[0012] The functional filler includes: ethylene-glycidyl methacrylate copolymer, trimethylolpropane and polyethylene glycol; the average molecular weight of the ethylene-glycidyl methacrylate copolymer is 8000-12000 g / mol, the copolymerization ratio of ethylene and glycidyl methacrylate is 80:20; the average molecular weight of the polyethylene glycol is 500.

[0013] reacting and mixing polypropylene resin and modified polyethylene wax to obtain modified polypropylene;

[0014] The polypropylene resin is homopolymer polypropylene with an average molecular weight of 20,000-25,000 g / mol.

[0015] The polyethylene wax raw material is oxidized and modified to obtain the main polyethylene wax;

[0016] The main polyethylene wax, the cross-linking agent and the modified polypropylene are subjected to in-situ reaction extrusion to obtain composite polypropylene;

[0017] The crosslinking agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate; the added molar ratio of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate is 2.2:1.

[0018] The composite polypropylene is subjected to high-temperature solid-phase post-treatment to obtain a composite material product, namely a polyethylene wax-modified polypropylene material.

[0019] Preferably, the in-situ polymerization grafting process is as follows: 100 parts of the polyethylene wax raw material and 2-7 parts of maleic anhydride are mixed, heated to 140-160° C. under anhydrous and oxygen-free conditions, 0.3-0.6 parts of dicumyl peroxide are added, and the mixture is reacted at a stirring speed of 200 rpm for 3 hours. After the reaction is completed, the temperature is lowered to 120° C., and a vacuum treatment is performed at an operating pressure of 0.1 atm for 30 minutes. The resulting product is extracted with acetone for 48 hours to obtain a prefabricated polyethylene wax.

[0020] Preferably, the melt mixing process is as follows: 100 parts of prefabricated polyethylene wax, 30-40 parts of ethylene-glycidyl methacrylate copolymer, 2-4 parts of trimethylolpropane and 1.5-2 parts of polyethylene glycol are mixed and fed at 120° C., melt-stirred at 150-190° C. for 20 minutes, heated to 220° C. and fed into the main reaction zone for mixing and reacting at a screw speed of 300 rpm for 1 hour, and then vacuum-exhausted at an operating pressure of 0.05 atm to extrude to obtain the modified polyethylene wax.

[0021] Preferably, the reaction mixing process is: after mixing 90 parts of polypropylene resin and 10-15 parts of modified polyethylene wax, feeding at 180°C, melt blending at 190-210°C at a screw speed of 270 rpm for 2 hours, vacuum exhausting at an operating pressure of 0.1 atm, and extruding to obtain modified polypropylene.

[0022] Preferably, the oxidative modification process is as follows: 100 parts of polyethylene wax raw material are melted at 150-170° C., 0.2-0.5 parts of benzoyl peroxide are added, dry air is introduced and stirred at a stirring speed of 300 rpm for 5-8 hours, nitrogen is introduced for purging for 2 hours, and the main polyethylene wax is obtained after cooling.

[0023] Preferably, the process of in-situ reaction extrusion is: mixing 80 parts of the modified polypropylene and 5-15 parts of the main polyethylene wax, feeding at 160°C, melting and reacting at 210-220°C, adding 0.5 parts of the cross-linking agent, maintaining the screw speed at 400 rpm for 2 hours, and extruding at 200°C to obtain composite polypropylene.

[0024] Preferably, the process of high-temperature solid-phase post-treatment is as follows: under a nitrogen atmosphere, the composite polypropylene is heated to 40-50°C and vacuum-treated at an operating pressure of 0.1 atm for 30-60 minutes, then heated to 120-140°C for 4 hours, then heated to 155°C for 16 hours, and cooled to 25°C at a cooling rate of 5°C / min to obtain a composite material product.

[0025] A polyethylene wax-modified polypropylene material comprises prefabricated polyethylene wax, modified polyethylene wax, polypropylene resin and a cross-linking agent.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The introduction of a uniformly distributed modified polyethylene wax into the polypropylene matrix successfully establishes an early anchoring structure, laying the foundation for the effective bonding of the subsequent main polyethylene wax. Furthermore, by introducing a specifically structured main polyethylene wax, the synergistic effect of the modified polyethylene wax on the early anchoring structure significantly improves the interfacial compatibility between the polyethylene wax and polypropylene. The dispersion morphology of the polyethylene wax dispersed phase is precisely controlled, enhancing the toughness and mechanical strength of the composite product.

[0028] 2. The main polyethylene wax and modified polypropylene matrix are effectively combined through in-situ reaction extrusion. In this process, the main polyethylene wax and the modified polypropylene matrix are selectively cross-linked in the interfacial area through the action of the cross-linking agent. While preventing the excessive aggregation of the polyethylene wax, a good co-dispersed cross-linking structure is formed, which significantly alleviates the stress concentration phenomenon of the composite material product, greatly improves the compatibility of polyethylene wax and polypropylene, and enables the composite material product to maintain toughness under long-term use.

[0029] 3. Through a specific modification process, modified polyethylene wax and main polyethylene wax with different properties are synthesized and then incorporated into the polypropylene matrix at different stages, achieving effective multi-level modification. Furthermore, by pre-adding functional fillers to the modified polyethylene wax, the polyethylene wax not only improves the performance of the polypropylene but also serves as a dispersant and interface modifier for the functional fillers, synergistically improving the performance of composite products and expanding the application range of composite products.

[0030] 4. Through high-temperature solid-phase post-treatment and temperature control during in-situ reaction extrusion, low-molecular-weight volatiles are effectively removed from the polymer, optimizing the crystalline morphology of the polypropylene composite and precisely regulating the microstructure of the polyethylene wax and polypropylene phases. The combination of these two processes effectively optimizes the specific properties of the different raw materials in the polypropylene composite, significantly improving the overall mechanical properties and aging resistance of the composite product, and ensuring its excellent application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a flow chart of the preparation process of the polyethylene wax modified polypropylene material in the present invention. DETAILED DESCRIPTION

[0032] The technical solutions of the present invention are described clearly and completely below through some embodiments and experimental examples. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Reference Figure 1As shown in the process flow chart, the present invention provides a polyethylene wax modified polypropylene material and a preparation method thereof, and the technical solution is as follows:

[0034] Example 1

[0035] 100 parts of the polyethylene wax raw material and 2 parts of maleic anhydride were mixed, heated to 140° C. under anhydrous and oxygen-free conditions, 0.3 parts of dicumyl peroxide were added, and the mixture was reacted at a stirring speed of 200 rpm for 3 hours. After the reaction was completed, the temperature was lowered to 120° C. and vacuum treated at an operating pressure of 0.1 atm for 30 minutes. The resulting product was extracted with acetone for 48 hours to obtain a prefabricated polyethylene wax.

[0036] 100 parts of prefabricated polyethylene wax, 30 parts of ethylene-glycidyl methacrylate copolymer, 2 parts of trimethylolpropane and 1.5 parts of polyethylene glycol were mixed and fed at 120°C, melt-stirred at 150°C for 20 minutes, heated to 220°C and fed into the main reaction zone. After mixing and reacting for 1 hour at a screw speed of 300 rpm, the mixture was vacuum-exhausted at an operating pressure of 0.05 atm and extruded to obtain modified polyethylene wax.

[0037] 90 parts of polypropylene resin and 10 parts of modified polyethylene wax were mixed, fed at 180° C., melt-blended at 190° C. with a screw speed of 270 rpm for 2 hours, and then vacuum-exhausted at an operating pressure of 0.1 atm to obtain modified polypropylene through extrusion.

[0038] 100 parts of polyethylene wax raw material was melted at 150° C., and 0.2 parts of benzoyl peroxide was added thereto. Dry air was introduced and the mixture was stirred at a stirring speed of 300 rpm for 5 hours. Nitrogen was then introduced for purging for 2 hours, and the main polyethylene wax was obtained after cooling.

[0039] 80 parts of the modified polypropylene and 5 parts of the main polyethylene wax were mixed, fed at 160°C, melt-reacted at 210°C, and 0.5 parts of the cross-linking agent were added. After the screw speed was maintained at 400 rpm for 2 hours, the mixture was extruded at 200°C to obtain composite polypropylene.

[0040] Under a nitrogen atmosphere, the composite polypropylene was heated to 40°C and vacuum treated at an operating pressure of 0.1atm for 30 minutes, then heated to 120°C for 4 hours, then heated to 155°C for 16 hours, and cooled to 25°C at a cooling rate of 5°C / min to obtain a composite material product.

[0041] Examples 2-16 differ from Example 1 in operating parameters, but are the same in process sequence and raw material selection.

[0042] The specific operating parameter changes are summarized in Tables 1 to 3.

[0043] Table 1 Operation parameter changes of Examples 1-16 (I)

[0044]

[0045] Table 2 Operation parameter changes of Examples 1-16 (II)

[0046]

[0047] Table 3 Operation parameter changes of Examples 1-16 (III)

[0048]

[0049] Comparative Example 1

[0050] The difference from Example 1 is that modified polyethylene wax is not added, and other process parameters are the same.

[0051] Comparative Example 2

[0052] The difference from Example 1 is that the main polyethylene wax is not added, and the other process parameters are the same.

[0053] Comparative Example 3

[0054] The difference from Example 5 is that during the in-situ reactive extrusion process, only 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane was used as a cross-linking agent, and other process parameters were the same.

[0055] Comparative Example 4

[0056] The difference from Example 5 is that during the in-situ reaction extrusion process, the amount of cross-linking agent added is increased to 2 parts, and the other process parameters are the same.

[0057] Comparative Example 5

[0058] The difference from Example 9 is that the main polyethylene wax is replaced by an equal amount of modified polyethylene wax, and the other process parameters are the same.

[0059] Comparative Example 6

[0060] The difference from Example 9 is that the modified polyethylene wax is not mixed with the polypropylene matrix in advance, but the modified polyethylene wax and the main polyethylene wax are added simultaneously during the in-situ reaction extrusion process, and the other process parameters are the same.

[0061] Comparative Example 7

[0062] The difference from Example 9 is that no functional filler is added, and other process parameters are the same.

[0063] Comparative Example 8

[0064] The difference from Example 13 is that during the high-temperature solid-phase post-treatment, the first and second stage preheating are not performed, and the heating treatment at 155° C. is directly performed, and the other process parameters are the same.

[0065] Comparative Example 9

[0066] The difference from Example 13 is that during the in-situ reaction extrusion process, the temperature of the melt reaction was changed to 180° C., and the other process parameters were the same.

[0067] Comparative Example 10

[0068] The difference from Example 13 is that high-temperature solid-phase post-treatment is not performed, and other process parameters are the same.

[0069] Experimental Example 1

[0070] The mechanical strength and toughness of the composite materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested, and the relevant data are summarized in Table 4.

[0071] The test method for toughness is: refer to the relevant test method of GBT1040.2-2022 standard, and use tensile modulus (MPa) to represent the toughness of the material sample.

[0072] The test method for mechanical strength is: refer to the relevant test method of GBT1843-2008 standard, adopt the cantilever beam unnotched impact test method, and use the impact strength (kJ / m 2 ) represents the mechanical strength of the material specimen.

[0073] Table 4 Tensile modulus and impact strength of the composite materials prepared in Examples 1-4 and Comparative Examples 1-2

[0074]

[0075] As shown in the data of Table 4, the composite materials prepared by Examples 1-4 have higher impact strength and better overall performance than Comparative Example 1 and Comparative Example 2 when the toughness gap is very small. Comparative Example 1 lacks modified polyethylene wax, which means that an effective early anchoring structure cannot be formed, resulting in poor bonding between the main polyethylene wax and the polypropylene matrix, reduced interfacial compatibility, and ultimately causing the impact strength to be significantly lower than that of Example 1. Although its tensile modulus is slightly higher than that of Example 1, the obvious disadvantage of impact strength indicates that its overall mechanical properties, especially its ability to resist impact damage, are relatively weak. Comparative Example 2 lacks the main polyethylene wax. Although there is an early anchoring structure formed by the modified polyethylene wax, the synergistic effect of the main polyethylene wax is lacking, and the modification effect of the polyethylene wax on polypropylene cannot be fully exerted, resulting in the morphology and interfacial compatibility of the polyethylene wax dispersed phase failing to reach the optimal state, so its impact strength is also much lower than that of Example 1.

[0076] In summary, the present invention significantly improves the interfacial compatibility of polyethylene wax and polypropylene by first introducing a modified polyethylene wax to create an early anchoring structure within the polypropylene matrix, and then introducing a main polyethylene wax and synergizing it with the anchoring structure. This synergistic effect precisely controls the morphology of the polyethylene wax dispersed phase, effectively improving the material's stress distribution and avoiding stress concentration, thereby enhancing the composite's overall performance and ensuring higher mechanical properties with minimal change in toughness.

[0077] Experimental Example 2

[0078] The composite materials prepared in Examples 5-8 and Comparative Examples 3-4 were tested for aging resistance, and the relevant data are summarized in Table 5.

[0079] The test method for aging resistance is: adopt a cyclic aging test method, keep the sample at 70℃ for 4 hours, cool it to -20℃ and keep it for 4 hours, and control the heating and cooling rates at 1-3℃ / min. Before the aging test and after 100 cycles and 500 cycles, test the tensile modulus of the sample and record it.

[0080] Table 5 Aging resistance of composite materials prepared in Examples 5-8 and Comparative Examples 3-4

[0081]

[0082] As shown in the data of Table 5, the composite materials of Examples 5-8 maintained a high tensile modulus compared to the initial value after 100 and 500 cycles of aging, showing good aging resistance. Comparative Example 3 only used 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a cross-linking agent, lacking the synergistic effect of triallyl isocyanurate. This resulted in an incomplete cross-linked structure and failed to fully form an ideal micro-cross-linked network at the phase interface, thereby affecting the structural stability and toughness retention of the material during long-term aging, as shown by a significant decrease in the tensile modulus after 500 cycles. Comparative Example 4 increased the amount of cross-linking agent to 2 parts, much higher than the 0.5 parts in the embodiment. Excessive cross-linking agent leads to excessive cross-linking, which reduces the mobility of the polymer segments and makes the material brittle, which is not conducive to maintaining toughness under long-term use. At the same time, excessive cross-linking also leads to excessive aggregation of polyethylene wax, forming an uneven cross-linked network, which also leads to a significant decrease in its tensile modulus after aging.

[0083] In summary, the invention achieves effective micro-crosslinking at the interface between the main polyethylene wax and the polypropylene matrix by precisely selecting and controlling the specific ratio and dosage of the composite crosslinking agent during the in-situ reactive extrusion process. This specific crosslinking method not only prevents excessive aggregation of the polyethylene wax, but also forms a well-dispersed crosslinked structure, significantly alleviating stress concentration and improving the compatibility of the polyethylene wax with polypropylene. This precisely controlled crosslinking technology ensures that the composite product maintains high toughness even under long-term cyclic aging conditions.

[0084] Experimental Example 3

[0085] The mechanical strength and toughness of the composite materials prepared in Examples 9-12 and Comparative Examples 5-7 were tested, and the relevant data are summarized in Table 6.

[0086] The test methods of mechanical strength and toughness refer to Experimental Example 1.

[0087] Table 6 Tensile modulus and impact strength of composite materials prepared in Examples 9-12 and Comparative Examples 5-7

[0088]

[0089] As shown in the data of Table 6, the composite products of Examples 9-12 exhibited excellent performance in terms of tensile modulus and impact strength. Comparative Example 5 completely replaced the main polyethylene wax with modified polyethylene wax, destroying the design of synergistic modification of the two characteristic waxes at different stages. Although the modified polyethylene wax contains functional fillers and can be combined with polypropylene, it lacks the further optimization effect of the main polyethylene wax on interface compatibility and dispersion morphology in the subsequent in-situ reaction extrusion stage, resulting in a decrease in impact strength. Comparative Example 6 added the modified polyethylene wax and the main polyethylene wax simultaneously during the in-situ reaction extrusion process, which prevented the modified polyethylene wax from fully reacting with polypropylene in advance to form the necessary early structure, and also affected the uniform dispersion of the functional filler and the interface regulation effect, resulting in a significant decrease in tensile modulus and impact strength. Comparative Example 7 did not add functional fillers, lacking the functional filler and its synergistic effect with the modified polyethylene wax. The tensile modulus and impact strength of the composite material were both the lowest, which highlights the important contribution of the functional filler pre-added to the modified polyethylene wax and pre-combined with the polypropylene matrix to the performance of the final product.

[0090] In summary, the present invention achieves multi-level synergistic modification by designing modified polyethylene wax and main polyethylene wax with different characteristics and introducing them into the polypropylene matrix at different stages. The modified polyethylene wax first interacts with polypropylene and serves as a carrier and dispersing aid for functional fillers, laying the foundation for the subsequent effects of the main polyethylene wax and imparting specific functions to the material. The main polyethylene wax further optimizes the interface and dispersion in subsequent stages. This multi-level, multi-component synergistic technical approach effectively improves the mechanical properties of the composite material.

[0091] Experimental Example 4

[0092] The composite materials prepared in Examples 13-16 and Comparative Examples 8-10 were tested for aging resistance, mechanical strength, and toughness. The relevant data are summarized in Table 7.

[0093] The test method for aging resistance refers to Experimental Example 2, and the test method for mechanical strength and toughness refers to Experimental Example 1.

[0094] Table 7 Aging resistance, mechanical strength and toughness of the composite materials prepared in Examples 13-16 and Comparative Examples 8-10

[0095]

[0096] As shown in the data of Table 7, the composite materials products of Examples 13-16 all perform well in terms of aging resistance and comprehensive mechanical properties. Comparative Example 8 omits the segmented preheating step in the high-temperature solid-phase post-treatment and directly uses 155°C for treatment. This results in incomplete removal of volatiles, insufficient adjustment of the internal structure due to excessively rapid temperature increase, and failure to achieve the optimal crystallization morphology and phase microstructure. Therefore, although its aging resistance and impact strength have improved, they are still inferior to Example 13 using a complete step-by-step treatment, showing the importance of segmented preheating for optimizing the treatment effect. Comparative Example 9 changes the melt reaction temperature during the in-situ reaction extrusion process, and its comprehensive performance is inferior to Example 13, which indirectly illustrates the importance of coordinated matching of various parameters in the entire process chain. Warm solid-phase post-treatment is an optimization based on the material formed in the preceding step. In the preceding step, the in-situ reaction extrusion temperature is inappropriate, which limits the upper limit of performance optimization that can be achieved by post-treatment. Comparative Example 10 does not undergo high-temperature solid-phase post-treatment at all, resulting in a large amount of low-molecular-weight volatiles remaining in the material, and the polymer crystal morphology and phase microstructure are not optimized. Therefore, its initial mechanical properties and aging resistance are the worst. This directly proves the importance of the high-temperature solid-phase post-treatment step for achieving the comprehensive performance of composite materials.

[0097] In summary, the present invention utilizes a specific multi-stage, high-temperature, solid-phase post-treatment process, including preheating at a specific temperature, vacuum treatment, high-temperature treatment with controlled duration, and a specific cooling rate. This process, coupled with precise temperature control, effectively removes low-molecular-weight volatiles, optimizes the crystalline morphology of the polypropylene composite, and precisely regulates the microstructure of the polyethylene wax and polypropylene phases. This meticulously controlled post-treatment technique significantly improves the overall mechanical properties and aging resistance of the composite product, resulting in a superior-performance composite product.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polyethylene wax-modified polypropylene material, characterized in that: The preparation method is as follows: In-situ polymerization and grafting of polyethylene wax raw materials to obtain prefabricated polyethylene wax; The in-situ polymerization grafting process comprises: mixing 100 parts of the polyethylene wax raw material and 2-7 parts of maleic anhydride by weight, heating to 140-160° C. under anhydrous and oxygen-free conditions, adding 0.3-0.6 parts of dicumyl peroxide, performing vacuum treatment after the reaction is completed, and extracting the resulting product with acetone to obtain the prefabricated polyethylene wax; Melting and mixing the functional filler and the prefabricated polyethylene wax to obtain modified polyethylene wax; Wherein, the functional filler comprises: ethylene-glycidyl methacrylate copolymer, trimethylolpropane and polyethylene glycol; reacting and mixing the polypropylene resin and the modified polyethylene wax to obtain modified polypropylene; oxidatively modifying the polyethylene wax raw material to obtain a main polyethylene wax; The oxidation modification process is as follows: 100 parts by mass of the polyethylene wax raw material are melted at 150-170° C., 0.2-0.5 parts of benzoyl peroxide are added, dry air is introduced and stirred at a stirring speed of 300 rpm for 5-8 hours, nitrogen is introduced for 2 hours, and the main polyethylene wax is obtained after cooling; In-situ reaction extrusion of the main polyethylene wax, the cross-linking agent and the modified polypropylene to obtain composite polypropylene; The in-situ reaction extrusion process is as follows: 80 parts of the modified polypropylene and 5-15 parts of the main polyethylene wax are mixed by weight, melt-reacted at 210-220° C., and 0.5 parts of the cross-linking agent are added. After the reaction is completed, the composite polypropylene is extruded to obtain the composite polypropylene. Wherein, the crosslinking agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate; The composite polypropylene is subjected to high-temperature solid-phase post-treatment to obtain a composite material product, namely the polyethylene wax-modified polypropylene material; The process of the high-temperature solid-phase post-treatment is as follows: heating the composite polypropylene to 40-50°C under a nitrogen atmosphere, and vacuum treating it for 30-60 minutes at an operating pressure of 0.1 atm, then heating it to 120-140°C for treatment, and then continuing to heat it to 155°C for treatment, and cooling it to obtain the composite material product.

2. The method for preparing a polyethylene wax-modified polypropylene material according to claim 1, wherein: The melt mixing process comprises: mixing 100 parts of the prefabricated polyethylene wax, 30-40 parts of the ethylene-glycidyl methacrylate copolymer, 2-4 parts of the trimethylolpropane and 1.5-2 parts of the polyethylene glycol, by mass, melting and stirring at 150-190° C., heating to 220° C., reacting, vacuum exhausting, and extruding to obtain the modified polyethylene wax.

3. The method for preparing a polyethylene wax-modified polypropylene material according to claim 1, wherein: The reaction and mixing process is as follows: 90 parts of the polypropylene resin and 10-15 parts of the modified polyethylene wax are mixed by mass, melted and blended at 190-210° C., vacuum-exhausted after the reaction, and extruded to obtain the modified polypropylene.

4. A polyethylene wax-modified polypropylene material, characterized in that: The polyethylene wax-modified polypropylene material is prepared by the preparation method according to any one of claims 1 to 3; the polyethylene wax-modified polypropylene material comprises: prefabricated polyethylene wax, modified polyethylene wax, polypropylene resin and a cross-linking agent.

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