Polypropylene material for logistics turnover and preparation process thereof

Abstract

The invention relates to the technical field of polypropylene materials, in particular to a polypropylene material for logistics turnover and a preparation process thereof. The polypropylene material for logistics turnover is prepared from the following components in parts by weight: 80 to 100 parts of polypropylene, 10 to 15 parts of modified nano zinc oxide, 5 to 10 parts of talcum powder, 3 to 5 parts of nucleating agent, 0.5 to 1.5 parts of lubricant, 0.5 to 1.0 part of antioxidant and 0.5 to 1.0 part of stabilizer. The preparation method comprises the following steps: S1, uniformly stirring polypropylene, modified nano zinc oxide, talcum powder, a nucleating agent, a lubricant, an antioxidant and a stabilizer to obtain a mixture; s2, adding the mixture into a twin-screw extruder for melt blending, extrusion and foaming to obtain the polypropylene material for logistics turnover, which not only has excellent mechanical properties, but also has excellent antibacterial properties and aging resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene materials, and particularly to a polypropylene material for logistics turnover and its preparation process. Background Art

[0002] With the rapid development of e-commerce, the logistics turnover volume has increased exponentially. As a widely used thermoplastic plastic, polypropylene (PP) has gradually become an important material in the logistics turnover field due to its good mechanical properties, chemical resistance, and lightweight characteristics. Polypropylene not only has excellent molding properties and cost-effectiveness but also shows great flexibility and adaptability in packaging, storage, and transportation.

[0003] However, polypropylene itself does not have antibacterial properties and is prone to breeding bacteria and microorganisms in humid or warm environments. Especially in the transportation of fruits and vegetables, polypropylene turnover boxes may be affected by fruit spoilage, which in turn affects food safety and hygiene and restricts its reuse in the logistics turnover process. In addition, polypropylene has weak resistance to ultraviolet rays. When exposed to sunlight for a long time, its physical properties will decline, such as embrittlement, reduced strength, and yellowing of color, which limits its application in outdoor or direct sunlight environments.

[0004] Therefore, we propose a polypropylene material for logistics turnover and its preparation process. Summary of the Invention

[0005] The purpose of the present invention is to provide a polypropylene material for logistics turnover and its preparation process to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation process of a polypropylene material for logistics turnover, comprising the following steps: Step S1: Stir polypropylene, modified nano-zinc oxide, talcum powder, nucleating agent, lubricant, antioxidant, and stabilizer evenly to obtain a mixture; Step S2: Add the mixture into a twin-screw extruder for melt blending, extrusion, and foaming to obtain the polypropylene material for logistics turnover.

[0007] Furthermore, the polypropylene material for logistics turnover comprises the following weight components: 80 - 100 parts of polypropylene, 10 - 15 parts of modified nano-zinc oxide, 5 - 10 parts of talcum powder, 3 - 5 parts of nucleating agent, 0.5 - 1.5 parts of lubricant, 0.5 - 1.0 part of antioxidant, and 0.5 - 1.0 part of stabilizer.

[0008] Furthermore, the preparation method of the modified nano-zinc oxide is as follows: Step A: Under nitrogen protection, mix nano-zinc oxide, absolute ethanol and deionized water evenly, heat up to 70 - 80 °C, add γ-(methacryloyloxy)propyltrimethoxysilane, and react for 4 - 6 h. After centrifugation, washing and drying, double-bond-containing nano-zinc oxide is obtained; Step B: Mix the double-bond-containing nano-zinc oxide and deionized water evenly, add methyl methacrylate, modified lignin and 4-epoxyisoeugenol, introduce nitrogen, add potassium persulfate, and react at 70 - 80 °C for 10 - 12 h. After centrifugation, washing and drying, an epoxy compound is obtained; Step C: Mix the epoxy compound, p-phenylenediamine and ethanol evenly, and react at 60 - 70 °C for 5 - 10 h. After filtration, washing and drying, modified nano-zinc oxide is obtained.

[0009] Further, in the above Step A, the mass ratio of nano-zinc oxide, absolute ethanol, deionized water and γ-(methacryloyloxy)propyltrimethoxysilane is 1:(15 - 20):(3 - 5):(2 - 4).

[0010] Further, in the above Step B, the mass ratio of the double-bond-containing nano-zinc oxide and deionized water is 1:(50 - 80).

[0011] Further, in the above Step B, the mass ratio of the double-bond-containing nano-zinc oxide, methyl methacrylate, modified lignin and 4-epoxyisoeugenol is 1:(1 - 2):(2 - 4):(0.5 - 1.5).

[0012] Further, the dosage of potassium persulfate is 1 - 3% of the total mass of the double-bond-containing nano-zinc oxide, methyl methacrylate, modified lignin and 4-epoxyisoeugenol.

[0013] Further, the preparation method of the modified lignin is as follows: Add alkali lignin and sodium hydroxide to a mixed solution of dimethyl sulfoxide and deionized water, stir until dissolved, heat up to 90 - 100 °C, add glycidyl methacrylate, and react for 3 - 5 h. After dialysis and drying, double-bond-containing lignin is obtained; Mix the double-bond-containing lignin and sodium hydroxide solution evenly, heat up to 80 - 90 °C, add 3-chloro-2-hydroxypropyltrimethylammonium chloride, and react for 4 - 6 h. After dialysis and drying, modified lignin is obtained.

[0014] Further, the mass ratio of the alkali lignin, sodium hydroxide and glycidyl methacrylate is 1:(0.2 - 0.4):(2 - 3).

[0015] Further, the mixed solution is composed of dimethyl sulfoxide and deionized water in a mass ratio of 1:1, and its dosage is 15 - 20 times that of the alkali lignin.

[0016] Furthermore, the mass ratio of the double-bond-containing lignin, sodium hydroxide solution and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride is 1:(15 - 20):(0.3 - 0.5), and the concentration of the sodium hydroxide solution is 20 wt%.

[0017] In the above technical solution, using glycidyl methacrylate (GMA) as a modifier, through the reaction of epoxy groups with the hydroxyl groups of lignin, unsaturated double bonds are grafted onto the lignin to obtain double-bond-containing lignin; at the same time, while the epoxy groups react with the hydroxyl groups to form ether bonds, new hydroxyl groups will be generated on the side chain, which can achieve continuous graft modification. Then, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride is used for modification to obtain double-bond-containing quaternized lignin, that is, modified lignin.

[0018] Furthermore, the mass ratio of the epoxy compound, p-phenylenediamine and ethanol is 1:(2 - 4):(15 - 20).

[0019] Furthermore, the lubricant is polyethylene wax.

[0020] Furthermore, the stabilizer is an organotin stabilizer.

[0021] Furthermore, the temperatures of each zone of the twin-screw extruder are as follows: the first zone is 178 - 182 °C, the second zone is 188 - 192 °C, the third zone is 198 - 202 °C, the fourth zone is 208 - 212 °C, the fifth zone is 220 - 225 °C, and the head is 215 - 220 °C; the screw speed is 120 - 180 r / min.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. For a polypropylene material for logistics turnover and its preparation process of the present invention, lignin, as a natural and non-toxic biomass material, not only has antibacterial activity, but also shows antioxidant and ultraviolet shielding capabilities. However, due to the complex structure of lignin, the content of its effective antibacterial components is relatively low. Therefore, in the solution, lignin is doubly modified by glycidyl methacrylate (GMA) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride, and double-bond active sites and quaternary ammonium salt groups are successfully introduced into the molecular structure of natural lignin to obtain modified lignin. Among them, the grafting of GMA endows lignin with free radical polymerization activity, and the quaternization treatment enables it to effectively inhibit the growth and reproduction of bacteria when in contact with bacteria, significantly improving the antibacterial performance of lignin.

[0023] 2. A polypropylene material for logistics turnover and its preparation process according to the present invention. Nano-zinc oxide has good ultraviolet resistance and antibacterial properties. The surface of nano-zinc oxide is modified by γ-(methacryloyloxy)propyltrimethoxysilane (KH570). While improving the dispersibility of zinc oxide, it endows it with active double bonds. Then, through free radical copolymerization, acrylic acid, modified lignin and 4-epoxyisoeugenol are copolymerized and coated on the surface of nano-zinc oxide to form a "core-shell" structure, which helps to improve the strength and toughness of polypropylene. Among them, 4-epoxyisoeugenol, as a derivative of eugenol, has certain antibacterial properties. The quaternized lignin coated on the surface of nano-zinc oxide and 4-epoxyisoeugenol form a dual antibacterial system, which jointly improves the antibacterial properties of the material. Finally, in order to further improve the anti-aging performance of the material, the reaction of epoxy groups with amino groups is used to graft p-phenylenediamine (PPDA) on the surface of the epoxy compound to achieve the grafting of anti-aging agents and obtain modified nano-zinc oxide. The polypropylene material for logistics turnover prepared by melt blending the modified nano-zinc oxide with polypropylene according to the present invention not only improves the mechanical properties of the material, but also endows it with excellent antibacterial and anti-aging properties. Specific embodiments

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] In this embodiment, polypropylene: the model is Hyosung R701 of South Korea; nano-zinc oxide: the particle size is 30 nm, sourced from Shanghai Yaotian New Material Technology Co., Ltd.; alkali lignin: the model is 471003, sourced from Merck; talcum powder: the particle size is 5000 mesh, sourced from Jiangyin Guangyuan Superfine Powder Co., Ltd.; nucleating agent: the model is Millad NX8000i; lubricant: polyethylene wax, the model is Honeywell AC-6A; antioxidant: the model is antioxidant 1010; stabilizer: the model is TM-181FS.

[0026] Unless otherwise specified, the following parts are all parts by mass.

[0027] Example 1: A preparation process of a polypropylene material for logistics turnover, including the following processes: Step S1: Stir 80 parts of polypropylene, 10 parts of modified nano-zinc oxide, 5 parts of talcum powder, 3 parts of nucleating agent, 0.5 part of lubricant, 0.5 part of antioxidant and 0.5 part of stabilizer evenly to obtain a mixture. Step S2: Add the mixture into a twin-screw extruder for melt blending, extrusion, and foaming to obtain a polypropylene material for logistics turnover; the temperatures of each zone of the twin-screw extruder are: Zone 1 at 178 °C, Zone 2 at 188 °C, Zone 3 at 198 °C, Zone 4 at 208 °C, Zone 5 at 220 °C, and the die head at 215 °C; the screw speed is 120 r / min; The preparation method of the modified nano-zinc oxide is as follows: Step A: Under nitrogen protection, mix 10 parts of nano-zinc oxide, 150 parts of absolute ethanol, and 30 parts of deionized water evenly, heat up to 70 °C, add 20 parts of γ-(methacryloyloxy)propyltrimethoxysilane, react for 4 h, and after centrifugation, washing, and drying, obtain double-bond-containing nano-zinc oxide; Step B: Mix 10 parts of double-bond-containing nano-zinc oxide and 500 parts of deionized water evenly, add 10 parts of methyl methacrylate, 20 parts of modified lignin, and 5 parts of 4-epoxyisoeugenol, introduce nitrogen, add 0.45 part of potassium persulfate, react at 70 °C for 10 h, and after centrifugation, washing, and drying, obtain an epoxy compound; Step C: Mix 10 parts of the epoxy compound, 20 parts of p-phenylenediamine, and 150 parts of an ethanol solution evenly, react at 60 °C for 10 h, and after filtration, washing, and drying, obtain the modified nano-zinc oxide; The preparation method of the modified lignin is as follows: Add 20 parts of alkali lignin and 4 parts of sodium hydroxide into a mixed solution of 150 parts of dimethyl sulfoxide and 150 parts of deionized water, stir until dissolved, heat up to 90 °C, add 40 parts of glycidyl methacrylate, react for 3 h, and after dialysis and drying, obtain double-bond-containing lignin; Mix 20 parts of double-bond-containing lignin and 300 parts of a 20 wt% sodium hydroxide solution evenly, heat up to 80 °C, add 6 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride, react for 4 h, and after dialysis and drying, obtain the modified lignin.

[0028] Example 2: A preparation process of a polypropylene material for logistics turnover, including the following processes: Step S1: Stir 90 parts of polypropylene, 12 parts of modified nano-zinc oxide, 8 parts of talcum powder, 4 parts of nucleating agent, 1 part of lubricant, 1 part of antioxidant, and 0.8 part of stabilizer evenly to obtain a mixture; Step S2: Add the mixture into a twin-screw extruder for melt blending, extrusion, and foaming to obtain a polypropylene material for logistics turnover; the temperatures of each zone of the twin-screw extruder are: Zone 1 at 180 °C, Zone 2 at 190 °C, Zone 3 at 200 °C, Zone 4 at 210 °C, Zone 5 at 222 °C, and the die head at 218 °C; the screw speed is 160 r / min; The preparation method of the modified nano-zinc oxide is as follows: Step A: Under nitrogen protection, 12 parts of nano zinc oxide, 220 parts of absolute ethanol and 48 parts of deionized water were mixed evenly, heated to 75 °C, 36 parts of γ-(methacryloyloxy)propyltrimethoxysilane were added, and the reaction was carried out for 5 h. After centrifugation, washing and drying, double bond-containing nano zinc oxide was obtained; Step B: 12 parts of double bond-containing nano zinc oxide and 720 parts of deionized water were mixed evenly, 18 parts of methyl methacrylate, 36 parts of modified lignin and 12 parts of 4-epoxyisoeugenol were added, nitrogen was introduced, 1.56 parts of potassium persulfate were added, and the reaction was carried out at 75 °C for 11 h. After centrifugation, washing and drying, an epoxy compound was obtained; Step C: 12 parts of the epoxy compound, 36 parts of p-phenylenediamine and 216 parts of ethanol solution were mixed evenly, and the reaction was carried out at 65 °C for 8 h. After filtration, washing and drying, modified nano zinc oxide was obtained; The preparation method of the modified lignin is as follows: 36 parts of alkali lignin and 10.8 parts of sodium hydroxide were added to a mixed solution of 320 parts of dimethyl sulfoxide and 320 parts of deionized water, stirred until dissolved, heated to 95 °C, 90 parts of glycidyl methacrylate were added, and the reaction was carried out for 4 h. After dialysis and drying, double bond-containing lignin was obtained; 36 parts of double bond-containing lignin and 650 parts of 20 wt% sodium hydroxide solution were mixed evenly, heated to 85 °C, 14.4 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride were added, and the reaction was carried out for 5 h. After dialysis and drying, modified lignin was obtained.

[0029] Example 3: A preparation process of a polypropylene material for logistics turnover includes the following processes: Step S1: 100 parts of polypropylene, 15 parts of modified nano zinc oxide, 10 parts of talcum powder, 5 parts of nucleating agent, 1.5 parts of lubricant, 1.0 part of antioxidant and 1.0 part of stabilizer were stirred evenly to obtain a mixture; Step S2: The mixture was added to a twin-screw extruder for melt blending, extrusion and foaming to obtain a polypropylene material for logistics turnover; the temperatures of each zone of the twin-screw extruder were: zone 1 182 °C, zone 2 192 °C, zone 3 202 °C, zone 4 212 °C, zone 5 225 °C, and the head 220 °C; the screw speed was 180 r / min; The preparation method of the modified nano zinc oxide is as follows: Step A: Under nitrogen protection, 15 parts of nano zinc oxide, 300 parts of absolute ethanol and 75 parts of deionized water were mixed evenly, heated to 80 °C, 60 parts of γ-(methacryloyloxy)propyltrimethoxysilane were added, and the reaction was carried out for 6 h. After centrifugation, washing and drying, double bond-containing nano zinc oxide was obtained; Step B: Mix 15 parts of double-bonded nano-zinc oxide and 1200 parts of deionized water evenly, add 30 parts of methyl methacrylate, 60 parts of modified lignin and 22.5 parts of 4-epoxyisoeugenol, introduce nitrogen, add 3.8 parts of potassium persulfate, and react at 80 °C for 12 h. After centrifugation, washing, and drying, an epoxy compound is obtained; Step C: Mix 15 parts of the epoxy compound, 60 parts of p-phenylenediamine and 300 parts of ethanol evenly, react at 70 °C for 5 h, and after filtration, washing, and drying, modified nano-zinc oxide is obtained; The preparation method of the modified lignin is as follows: Add 60 parts of alkali lignin and 24 parts of sodium hydroxide to a mixed solution of 600 parts of dimethyl sulfoxide and 600 parts of deionized water, stir until dissolved, heat up to 100 °C, add 180 parts of glycidyl methacrylate, react for 5 h, and after dialysis and drying, double-bonded lignin is obtained; Mix 60 parts of double-bonded lignin and 1200 parts of 20 wt% sodium hydroxide solution evenly, heat up to 90 °C, add 30 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride, react for 6 h, and after dialysis and drying, modified lignin is obtained.

[0030] Comparative Example 1: A preparation process of a polypropylene material for logistics turnover includes the following processes: Step S1: Stir 90 parts of polypropylene, 12 parts of nano-zinc oxide, 8 parts of talcum powder, 4 parts of nucleating agent, 1 part of lubricant, 1 part of antioxidant and 0.8 part of stabilizer evenly to obtain a mixture; Step S2: Add the mixture to a twin-screw extruder for melt blending, extrusion, and foaming to obtain a polypropylene material for logistics turnover; the temperatures of each zone of the twin-screw extruder are: zone 1 at 180 °C, zone 2 at 190 °C, zone 3 at 200 °C, zone 4 at 210 °C, zone 5 at 222 °C, and the head at 218 °C; the screw speed is 160 r / min; Compared with Example 2, in Comparative Example 1, the modified nano-zinc oxide is replaced with nano-zinc oxide of the same mass.

[0031] Comparative Example 2: A preparation process of a polypropylene material for logistics turnover includes the following processes: The preparation method of the modified nano-zinc oxide is as follows: Step A: Under nitrogen protection, mix 12 parts of nano-zinc oxide, 220 parts of absolute ethanol and 48 parts of deionized water evenly, heat up to 75 °C, add 36 parts of γ-(methacryloyloxy)propyltrimethoxysilane, react for 5 h, and after centrifugation, washing, and drying, double-bonded nano-zinc oxide is obtained; Step B: Mix 12 parts of double bond-containing nano zinc oxide and 720 parts of deionized water evenly, add 18 parts of methyl methacrylate, 36 parts of lignin, and 12 parts of 4-epoxyisoeugenol. Introduce nitrogen, add 1.56 parts of potassium persulfate, and react at 75 °C for 11 h. After centrifugation, washing, and drying, an epoxy compound is obtained; Step C: Mix 12 parts of the epoxy compound, 36 parts of p-phenylenediamine, and 216 parts of ethanol solution evenly, and react at 65 °C for 8 h. After filtration, washing, and drying, modified nano zinc oxide is obtained; Compared with Example 2, in Comparative Example 2, the modified lignin was replaced with lignin of the same mass, and other steps were the same as those in Example 2.

[0032] Comparative Example 3: A preparation process of a polypropylene material for logistics turnover, including the following processes: The preparation method of the modified nano zinc oxide is as follows: Step A: Under nitrogen protection, mix 12 parts of nano zinc oxide, 220 parts of absolute ethanol, and 48 parts of deionized water evenly, heat up to 75 °C, add 36 parts of γ-(methacryloyloxy)propyltrimethoxysilane, and react for 5 h. After centrifugation, washing, and drying, double bond-containing nano zinc oxide is obtained; Step B; Mix 12 parts of double bond-containing nano zinc oxide and 720 parts of deionized water evenly, add 18 parts of methyl methacrylate, 36 parts of modified lignin, introduce nitrogen, add 1.56 parts of potassium persulfate, and react at 75 °C for 11 h. After centrifugation, washing, and drying, modified nano zinc oxide is obtained; Compared with Example 2, in step B of Comparative Example 3, 4-epoxyisoeugenol is not added, and step C is deleted, and other steps are the same as those in Example 2.

[0033] Comparative Example 4: A preparation process of a polypropylene material for logistics turnover, including the following processes: The preparation method of the modified nano zinc oxide is as follows: Step A: Under nitrogen protection, mix 12 parts of nano zinc oxide, 220 parts of absolute ethanol, and 48 parts of deionized water evenly, heat up to 75 °C, add 36 parts of γ-(methacryloyloxy)propyltrimethoxysilane, and react for 5 h. After centrifugation, washing, and drying, double bond-containing nano zinc oxide is obtained; Step B; Mix 12 parts of double bond-containing nano zinc oxide and 720 parts of deionized water evenly, add 18 parts of methyl methacrylate, 12 parts of modified lignin, and 12 parts of 4-epoxyisoeugenol, introduce nitrogen, add 1.56 parts of potassium persulfate, and react at 75 °C for 11 h. After centrifugation, washing, and drying, an epoxy compound is obtained; Step C: Mix 12 parts of epoxy compound, 36 parts of p - aminodiphenylamine and 216 parts of ethanol solution evenly, react at 65 °C for 8 h, and obtain modified nano - zinc oxide after filtration, washing and drying; Compared with Example 2, in Step B of Comparative Example 4, the mass ratio of double - bond - containing nano - zinc oxide, methyl methacrylate, modified lignin and 4 - epoxy - isoeugenol is 1:1.5:1:1; other steps are the same as those in Example 2.

[0034] Experiment: Take the polypropylene materials for logistics turnover obtained in Examples 1 - 3 and Comparative Examples 1 - 4, prepare specimens, and detect and record the performance of each of them respectively: Determine the tensile properties according to GB / T1040.2 - 2022. The size of the specimen is 150 mm×10 mm×4 mm, the determination temperature is 25 °C, and the tensile rate is 50 mm / min; conduct xenon lamp aging test according to GB / T 16422.2 - 2014: Use xenon lamp as the light source, the radiation intensity is 550 W / m 2 , the blackboard temperature is 45 °C, the temperature inside the box is 30 °C, the relative humidity is 80%, the test time is 360 h, determine the tensile strength before and after aging, and calculate the performance degradation rate = 1 - tensile strength after aging / initial tensile strength; determine the antibacterial performance according to the film - sticking method in GB / T 31402 - 2023, and the test strain is Staphylococcus aureus (the concentration of the bacterial population is 3.0×10 5 cfu / mL).

[0035] The test results are as follows: According to the data in the above table, the following conclusions can be clearly obtained: Compared with Examples 1 - 3, the tensile strength and antibacterial rate of the products obtained in Comparative Example 1 and Comparative Example 2 both decrease, and the performance degradation rate increases, indicating that the modified nano - zinc oxide prepared by the present invention can improve the mechanical properties, anti - aging properties and antibacterial properties of the material; the modified lignin prepared by the present invention is double - modified by glycidyl methacrylate and 3 - chloro - 2 - hydroxypropyl trimethyl ammonium chloride, and has a better modification effect compared with lignin, and can effectively improve the antibacterial performance of the material.

[0036] Compared with Examples 1 - 3, the anti - aging properties and antibacterial rate of the products obtained in Comparative Example 3 both decrease. It can be seen that by introducing 4 - epoxy - isoeugenol in the present invention, while improving the antibacterial property, the epoxy group reaction sites are also increased, which is beneficial to the grafting of antioxidant.

[0037] Compared with Examples 1 - 3, the tensile strength, anti - aging properties and antibacterial rate of the products obtained in Comparative Example 4 all decrease. It can be seen that when the addition amount of modified lignin is reduced, the performance of the modified nano - zinc oxide will decline.

[0038] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A preparation process of a polypropylene material for logistics turnover, characterized in that: It includes the following steps: Step S1: Stir polypropylene, modified nano-zinc oxide, talcum powder, nucleating agent, lubricant, antioxidant and stabilizer evenly to obtain a mixture. Step S2: Add the mixture into a twin-screw extruder for melt blending, extrusion and foaming to obtain a polypropylene material for logistics turnover.

2. The preparation process of a polypropylene material for logistics turnover according to claim 1, characterized in that: The polypropylene material for logistics turnover includes the following weight components: 80 - 100 parts of polypropylene, 10 - 15 parts of modified nano-zinc oxide, 5 - 10 parts of talcum powder, 3 - 5 parts of nucleating agent, 0.5 - 1.5 parts of lubricant, 0.5 - 1.0 part of antioxidant, and 0.5 - 1.0 part of stabilizer.

3. The preparation process of a polypropylene material for logistics turnover according to claim 2, characterized in that: The preparation method of the modified nano-zinc oxide is as follows: Step A: Under nitrogen protection, mix nano-zinc oxide, anhydrous ethanol and deionized water evenly, heat up to 70 - 80 °C, add γ-(methacryloyloxy)propyltrimethoxysilane, react for 4 - 6 h, and after centrifugation, washing and drying, obtain nano-zinc oxide containing double bonds. Step B: Mix the nano-zinc oxide containing double bonds and deionized water evenly, add methyl methacrylate, modified lignin and 4-epoxyisoeugenol, introduce nitrogen, add potassium persulfate, and react at 70 - 80 °C for 10 - 12 h. After centrifugation, washing and drying, obtain an epoxy compound. Step C: Mix the epoxy compound, p-phenylenediamine and ethanol evenly, react at 60 - 70 °C for 5 - 10 h, and after filtration, washing and drying, obtain modified nano-zinc oxide.

4. The preparation process of a polypropylene material for logistics turnover according to claim 3, characterized in that: In Step A, the mass ratio of nano-zinc oxide, anhydrous ethanol, deionized water and γ-(methacryloyloxy)propyltrimethoxysilane is 1:(15 - 20):(3 - 5):(2 - 4).

5. The preparation process of a polypropylene material for logistics turnover according to claim 3, characterized in that: In Step B, the mass ratio of nano-zinc oxide containing double bonds, methyl methacrylate, modified lignin and 4-epoxyisoeugenol is 1:(1 - 2):(2 - 4):(0.5 - 1.5).

6. The preparation process of a polypropylene material for logistics turnover according to claim 5, characterized in that: The preparation method of the modified lignin is as follows: Add alkali lignin and sodium hydroxide into a mixed solution of dimethyl sulfoxide and deionized water, stir until dissolved, heat up to 90 - 100 °C, add glycidyl methacrylate, react for 3 - 5 h, and after dialysis and drying, obtain lignin containing double bonds. Mix the lignin containing double bonds and sodium hydroxide solution evenly, heat up to 80 - 90 °C, add 3-chloro-2-hydroxypropyltrimethylammonium chloride, react for 4 - 6 h, and after dialysis and drying, obtain modified lignin.

7. The preparation process of a polypropylene material for logistics turnover according to claim 6, characterized in that: The mass ratio of alkali lignin, sodium hydroxide and glycidyl methacrylate is 1:(0.2 - 0.4):(2 - 3).

8. The preparation process of a polypropylene material for logistics turnover according to claim 6, characterized in that: The mass ratio of lignin containing double bonds, sodium hydroxide solution and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:(15 - 20):(0.3 - 0.5).

9. The preparation process of a polypropylene material for logistics turnover according to claim 3, characterized in that: In Step C, the mass ratio of the epoxy compound and p-phenylenediamine is 1:(2 - 4).

10. A polypropylene material for logistics turnover prepared by the preparation process according to any one of claims 1 - 9.

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