Low-temperature-resistant turnover box and preparation method thereof

Abstract

The application discloses a low-temperature-resistant turnover box and a preparation method thereof, and relates to the technical field of high polymer materials.The low-temperature-resistant turnover box comprises the following raw materials in mass parts: 60-70 parts of polypropylene, 5-10 parts of a modified nucleating agent, 15-25 parts of amine-based ternary ethylene-propylene rubber, 0.2-1 part of a lubricant, 0.5-1 part of a processing aid, and 1-4 parts of a pigment.The modified nucleating agent and the amine-based binary ethylene-propylene rubber are added in the polypropylene, so that the epoxy resin is endowed with excellent impact toughness and low-temperature resistance, and the turnover box can be used in cold storage and high-cold conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a low-temperature-resistant turnover box and a preparation method thereof. BACKGROUND

[0002] With the development of transportation industry and container industry, convenient and safe transportation can ensure the transportation quality and reduce the transportation cost, which makes the turnover box play an important role in the whole transportation process. The turnover box is also called a logistics box, which is widely used in machinery, automobile, household appliance, light industry, electronics and other industries, can resist acid, alkali and oil stains, is non-toxic and odorless, and can be used to hold mechanical, household appliance, fruits and vegetables and the like. Meanwhile, the turnover box can be matched with various logistics containers and work station appliances, and is used in various warehouses, production sites and other places, and is an essential product in production and logistics transportation. The plastic turnover box is mainly made of polypropylene, polyethylene and the like as raw materials, and is made by injection molding. Polypropylene has been the focus of the automobile industry and the plastics industry because of its small density, high strength, large hardness, wear resistance, bending fatigue resistance, high heat resistance, excellent moisture and chemical resistance, easy processing, low price and the like. The unmodified polypropylene parts often have a large amount of internal stress in the matrix due to rapid cooling and inability to crystallize naturally during injection molding. In a low-temperature environment, the high molecular chains in the material are restricted in movement and cannot effectively transfer / diffuse the internal stress and external destructive force, so that the cracking of the parts is more likely to occur.

[0003] The existing methods for improving the low-temperature embrittlement of polypropylene mainly include two methods of adding nucleating agent and adding toughening material. The beta nucleating agent is added to the raw material to change the crystal form of polypropylene. This method is simple to operate and can realize industrialized production, but the low-temperature embrittlement effect is poor below-5℃, and has high requirements for the process control conditions and post-processing technology of downstream processing enterprises. At the same time, the reproducibility and stability of the nucleating agent are poor during secondary processing. The addition of toughening material can effectively improve the low-temperature brittleness of polypropylene, but the addition amount is large, the production cost is high, and it is difficult to realize industrialized production; the completeness of the polypropylene molecular chain is easily damaged during secondary processing, and the processing technology is relatively complex; in addition, the addition of the toughening material will cause the rigidity or other key performance to be poor, which is not worth the loss; the mixing effect of the double-screw extruder is poor. Therefore, it is the direction of the technical personnel in the field to develop a new type of low-temperature-resistant and high-impact-resistant turnover box material. SUMMARY

[0004] The present application aims to provide a low-temperature-resistant turnover box and a preparation method thereof, which solve the following technical problems:

[0005] The existing polypropylene turnover box has the problems of low-temperature brittleness and poor impact resistance.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A low-temperature-resistant turnover box, comprising at least the following quality parts of raw materials:

[0008] Polypropylene 60-70 parts by mass; modified nucleating agent 5-10 parts by mass; aminated ternary ethylene-propylene rubber 15-25 parts by mass; lubricant 0.2-1 part by mass; processing aid 0.5-1 part by mass; pigment 1-4 parts by mass.

[0009] Preferably, the preparation method of the modified nucleating agent comprises the following steps:

[0010] Xylene and polypropylene are heated and mixed, a solution of dicumyl peroxide in xylene is added, and a solution of glycidyl methacrylate in xylene is added dropwise for reaction, and after settling and drying, a graft copolymer is obtained;

[0011] The beta nucleating agent and anhydrous calcium sulfate whiskers are dispersed in anhydrous ethanol and ultrasonically treated, and after suction filtration and drying, a whisker-loaded beta nucleating agent is obtained;

[0012] The whisker-loaded beta nucleating agent, gamma-aminopropyl triethoxysilane, anhydrous ethanol and deionized water are mixed, stirred and reacted, filtered and dried to obtain an activated whisker-loaded beta nucleating agent;

[0013] The graft copolymer and the activated whisker-loaded beta nucleating agent are pre-mixed in a high-speed mixer, and then melt blended to obtain a modified nucleating agent.

[0014] Preferably, the mass ratio of glycidyl methacrylate to polypropylene is 0.15:1-0.25:1, and the mass ratio of beta nucleating agent to anhydrous calcium sulfate whiskers is 1:8-1:12.

[0015] Preferably, the mass ratio of the whisker-loaded beta nucleating agent to the gamma-aminopropyl triethoxysilane is 20:1-22:1, and the mass ratio of the graft copolymer to the activated whisker-loaded beta nucleating agent is 1:0.8-1:1.2.

[0016] Preferably, the preparation method of the aminated ternary ethylene-propylene rubber comprises the following steps:

[0017] The ethyl acetate solution of ternary ethylene-propylene rubber and the ethyl acetate solution of mercaptoethylamine are mixed, and dimethyl anisole is added, and after stirring, ultraviolet light is irradiated, and after flocculation and drying, an aminated ternary ethylene-propylene rubber is obtained.

[0018] Preferably, the mass ratio of the ternary ethylene-propylene rubber, the mercaptoethylamine and the dimethyl anisole is 1:0.4-0.6:0.01-0.02.

[0019] Preferably, the processing aid is any one or mixture of several of antioxidant 1010, antioxidant 168, polyethylene wax, ethylene bis-stearamide or calcium stearate, the pigment is any one or mixture of several of inorganic pigment or organic pigment, and the lubricant is any one or several of silicone lubricant or erucic amide lubricant.

[0020] A method for preparing the low-temperature-resistant turnover box as described above, comprising at least the following steps:

[0021] adding polypropylene, modified nucleating agent, amine-based EPDM rubber, lubricant, processing aid and pigment into a high-speed mixer to obtain a premix;

[0022] feeding the premix into a twin-screw extruder for melt blending and granulation, and obtaining composite particles after extrusion, cooling and granulation;

[0023] feeding the composite particles into an injection molding machine for injection molding to obtain a molded turnover box;

[0024] obtaining a low-temperature-resistant turnover box after heat treatment of the molded turnover box.

[0025] Preferably, the temperature of the twin-screw extruder is set to zone 1 160-170℃, zone 2 170-180℃, zone 3 180-190℃, zone 4 175-185℃, and the temperature of the injection molding machine is set to zone 1 170-180℃, zone 2 180-190℃, zone 3 190-200℃, nozzle temperature 185-195℃, and mold temperature 40-60℃; the heat treatment temperature is 100-110℃, and the time is 30-40min.

[0026] The beneficial effects of the present application are:

[0027] The present application adds modified nucleating agent and amine-based EPDM rubber into polypropylene for melt blending, and prepares a low-temperature-resistant turnover box after injection molding, thereby improving the low-temperature resistance and impact resistance of the polypropylene turnover box. The modified nucleating agent induces the formation of β crystal form of polypropylene, and the β crystal lamella slips and deforms when impacted at low temperature, effectively absorbs fracture energy and improves impact strength. Meanwhile, the amine-based EPDM rubber and the grafted glycidyl methacrylate on the modified nucleating agent and the polypropylene graft copolymer form a covalent crosslinking network, preventing crack propagation, so that the box body can withstand severe impact without cracking during cold chain transportation, and the residual -SH groups on the surface of the amine-based EPDM rubber can be reorganized through heat treatment after impact key fracture, thereby prolonging the service life of the turnover box. The low-temperature-resistant turnover box prepared by the present application can be used in cold storage and high-cold conditions, and is suitable for continuous cold storage.

[0028] The modified nucleating agent prepared by the application uniformly loads the beta nucleating agent on the surface of anhydrous calcium sulfate whisker through ultrasonic treatment, and after activation by gamma-aminopropyl triethoxysilane, the amino group on the surface reacts with the epoxy group of the glycidyl methacrylate and polypropylene graft copolymer to form a chemical bond, solving the compatibility problem of inorganic fillers and organic matrix, making the nucleating agent and the whisker uniformly dispersed in the polypropylene, avoiding performance fluctuations caused by agglomeration. The high aspect ratio structure of the whisker can act as a "dispersion skeleton" for the beta nucleating agent, allowing the nucleating agent to be uniformly anchored on the surface of the whisker at the nanoscale, making the nucleating agent uniformly dispersed in the polypropylene, improving the nucleation efficiency, and the anchoring effect of the whisker on the nucleating agent can inhibit its migration, thereby stably improving the low-temperature toughness of the material and avoiding the decrease in rigidity caused by the change in crystalline morphology. At the same time, the long-chain structure of the glycidyl methacrylate and polypropylene graft copolymer can reduce the viscosity of the molten system, improve the flowability of the material, and reduce defects such as material shortage and shrinkage during injection molding.

[0029] The amine-based ternary ethylene-propylene rubber prepared by the application forms a "chemical anchoring-elastic toughening" synergistic effect with the polypropylene. The amine group introduced into the molecular chain of the ternary ethylene-propylene rubber can form hydrogen bonds or acid-base interactions with the epoxy groups of the graft copolymer and the amino groups of the modified nucleating agent, improving the interfacial bonding force of the two phases, avoiding phase separation during low-temperature impact, and ensuring effective energy transfer. Moreover, the ternary ethylene-propylene rubber itself has excellent low-temperature elasticity, and after amination, its dispersion size in the polypropylene matrix is refined, forming a uniform "elastic microzone", which can still absorb energy by silver streak initiation and shear band expansion at extremely low temperatures, improving the material's elongation at break. Moreover, the amine group can capture free radicals generated by the degradation of polypropylene, and synergize with antioxidants to extend the service life of the turnover box. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0031] Figure 1 It is a low-temperature-resistant turnover box prepared in an embodiment. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] The preparation method of the modified nucleating agent of Example 1 comprises the following steps:

[0034] 65 g of polypropylene (SP179) was dissolved in 300 mL of xylene to obtain a xylene solution of polypropylene, 2 g of dicumyl peroxide was added to 20 mL of xylene to obtain a xylene solution of dicumyl peroxide, 13 g of glycidyl methacrylate was added to 50 mL of xylene to obtain a xylene solution of glycidyl methacrylate, the above-mentioned xylene solution of polypropylene and xylene solution of dicumyl peroxide were mixed, and after 20 min, the above-mentioned xylene solution of glycidyl methacrylate was added dropwise into the kettle using a peristaltic pump, and the dropping was completed within 2.5 h, and the reaction was continued for 3.5 h, and then the unreacted glycidyl methacrylate and dicumyl peroxide were removed by repeatedly dissolving and precipitating three times with xylene as the solvent and acetone as the precipitant, and finally the product was vacuum dried at 60°C for 6 h to obtain a graft copolymer;

[0035] 5 g of β nucleating agent (TMB-5) and 50 g of anhydrous calcium sulfate whiskers were dispersed in 200 mL of anhydrous ethanol, and then ultrasonically treated at 50°C for 60 min using an ultrasonic cleaner, and then filtered under vacuum, and then placed in a drying oven at 50°C for 12 h to obtain whisker-loaded β nucleating agent;

[0036] The above-mentioned 55 g of whisker-loaded β nucleating agent, 2.75 g of γ-aminopropyl triethoxysilane, 150 mL of anhydrous ethanol and 50 mL of deionized water were sequentially added into a 250 mL reaction kettle, and then stirred and reacted at room temperature for 6 h, and then the product was filtered and naturally air-dried, and then the temperature was increased to 120°C for further drying for 2 h, and then the unreacted γ-aminopropyl triethoxysilane was removed by Soxhlet extraction with anhydrous ethanol for 24 h, and finally vacuum dried at 60°C for 12 h to obtain activated whisker-loaded β nucleating agent;

[0037] The above-mentioned 50 g of graft copolymer and 50 g of activated whisker-loaded β nucleating agent were pre-mixed in a high-speed mixer, and then transferred into a HAAKE torque rheometer for melt blending, the temperature of the mixing chamber was 180°C, the rotor rotation speed was 60 rpm, and the mixing time was 10 min to obtain a modified nucleating agent.

[0038] The preparation method of the modified nucleating agent of Example 2 comprises the following steps:

[0039] Dissolve 65 g of polypropylene (SP179) in 300 mL of xylene to obtain a xylene solution of polypropylene, dissolve 2 g of dicumyl peroxide in 20 mL of xylene to obtain a xylene solution of dicumyl peroxide, dissolve 13 g of glycidyl methacrylate in 50 mL of xylene to obtain a xylene solution of glycidyl methacrylate, mix the xylene solution of polypropylene and the xylene solution of dicumyl peroxide, and after 20 min, add the xylene solution of glycidyl methacrylate into the kettle by using a peristaltic pump, and drop it in 2.5 h, continue to react for 3.5 h, remove unreacted glycidyl methacrylate and dicumyl peroxide by repeatedly dissolving and precipitating three times with xylene as the solvent and acetone as the precipitant, and finally, vacuum dry the product at 60 °C for 6 h to obtain a grafted copolymer;

[0040] Disperse 5 g of β nucleating agent (TMB-5) and 55 g of anhydrous calcium sulfate whiskers in 200 mL of anhydrous ethanol, ultrasonically treat with an ultrasonic cleaner at 50 °C for 60 min, then perform suction filtration with a vacuum pump, and place in a drying oven at 50 °C for 12 h to obtain whisker-loaded β nucleating agent;

[0041] Add the above 55 g of whisker-loaded β nucleating agent, 2.75 g of γ-aminopropyl triethoxysilane, 150 mL of anhydrous ethanol, and 50 mL of deionized water into a 250 mL reaction kettle in sequence, stir and react at room temperature for 6 h, filter out the product and naturally air dry, then heat to 120 °C and continue to dry for 2 h, then Soxhlet extract with anhydrous ethanol for 24 h to remove unreacted γ-aminopropyl triethoxysilane, and finally vacuum dry at 60 °C for 12 h to obtain activated whisker-loaded β nucleating agent;

[0042] Pre-mix the above 50 g of grafted copolymer and 55 g of activated whisker-loaded β nucleating agent in a high-speed mixer, then melt blend in a Haake torque rheometer, with a mixing chamber temperature of 180 °C, a rotor rotation speed of 60 rpm, and a mixing time of 10 min to obtain a modified nucleating agent.

[0043] The preparation method of the amine-based ternary ethylene propylene rubber includes the following steps:

[0044] Take 100 g of ethylene propylene diene rubber (6950C) and add it to 400 mL of ethyl acetate to obtain an ethyl acetate solution of ethylene propylene diene rubber. Take 50 g of mercaptoethylamine and dissolve it in 400 mL of ethyl acetate to obtain an ethyl acetate solution of mercaptoethylamine. Mix the ethyl acetate solution of ethylene propylene diene rubber and the ethyl acetate solution of mercaptoethylamine, add 1.5 g of benzo pinacol as a photoinitiator, stir for 15 min, then introduce nitrogen to remove air, and then place it in a UV lamp box. Use a UV lamp with a wavelength of 365 nm and a light intensity setting of 75% to irradiate for 6 h. Then add it to 500 mL of anhydrous ethanol, flocculate, and continue to dissolve with n-hexane. After three times of dissolution and flocculation, dry to obtain amine-modified ethylene propylene diene rubber.

[0045] Example 4 A method for preparing a low-temperature-resistant turnover box, at least comprising the following steps:

[0046] Take 65 parts by mass of polypropylene (SP179), 7 parts by mass of the modified nucleating agent prepared in Example 1, 20 parts by mass of the amine-modified ethylene propylene diene rubber prepared in Example 3, 0.5 parts by mass of a mustard amide lubricant, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, 0.4 parts by mass of polyethylene wax, and 2 parts by mass of titanium white powder into a high-speed mixer, mix at 65°C and 1000 r / min for 8 min to obtain a premix;

[0047] Put the premix into a twin-screw extruder for melt blending and granulation. The temperature of each zone of the extruder is: Zone 1 165°C, Zone 2 175°C, Zone 3 185°C, Zone 4 180°C, the die temperature is 175°C, the screw speed is 200 r / min, the feeding rate is 30 r / min, and the extruded melt is cut into particles after water cooling and air drying to obtain composite particles;

[0048] The above composite particles are injected into an injection molding machine for injection molding. The barrel temperature is: Zone 1 175°C, Zone 2 185°C, Zone 3 195°C, the nozzle temperature is 190°C, the mold temperature is 50°C, the clamping force is 800 kN, the injection pressure is 80 MPa, the holding pressure is 60 MPa, the holding time is 15 s, and the cooling time is 30 s to obtain a molded turnover box;

[0049] The above molded turnover box is treated at 110°C for 30 min and naturally cooled to room temperature to obtain a low-temperature-resistant turnover box.

[0050] Example 5 A method for preparing a low-temperature-resistant turnover box, at least comprising the following steps:

[0051] Put 65 parts by mass of polypropylene (SP179), 7 parts by mass of the modified nucleating agent prepared in Example 2, 20 parts by mass of the amine-based ternary ethylene-propylene rubber prepared in Example 3, 0.5 parts by mass of a erucamide lubricant, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, 0.4 parts by mass of polyethylene wax, and 2 parts by mass of titanium white into a high-speed mixer, mix at 65°C and 1000 r / min for 8 min to obtain a premix;

[0052] Put the premix into a twin-screw extruder for melt blending and granulation, the temperature of each zone of the extruder is: zone 1 165°C, zone 2 175°C, zone 3 185°C, zone 4 180°C, the die temperature is 175°C, the screw rotation speed is 200 r / min, the feeding rate is 30 r / min, the extruded melt is cut into particles after water cooling and air drying to obtain composite particles;

[0053] Put the above composite particles into an injection molding machine for injection molding, the barrel temperature is: zone 1 175°C, zone 2 185°C, zone 3 195°C, the nozzle temperature is 190°C, the mold temperature is 50°C, the clamping force is 800 kN, the injection pressure is 80 MPa, the holding pressure is 60 MPa, the holding time is 15 s, the cooling time is 30 s, and a molded turnover box is obtained.

[0054] Put the above molded turnover box at 110°C for 30 min, and naturally cool to room temperature to obtain a low-temperature-resistant turnover box.

[0055] Example 6 A method for preparing a low-temperature-resistant turnover box, at least comprising the following steps:

[0056] Put 70 parts by mass of polypropylene (SP179), 10 parts by mass of the modified nucleating agent prepared in Example 1, 25 parts by mass of the amine-based ternary ethylene-propylene rubber prepared in Example 3, 0.2 parts by mass of a erucamide lubricant, 0.1 parts by mass of antioxidant 1010, 0.1 parts by mass of antioxidant 168, 0.3 parts by mass of polyethylene wax, and 4 parts by mass of titanium white into a high-speed mixer, mix at 65°C and 1000 r / min for 8 min to obtain a premix;

[0057] Put the premix into a twin-screw extruder for melt blending and granulation, the temperature of each zone of the extruder is: zone 1 165°C, zone 2 175°C, zone 3 185°C, zone 4 180°C, the die temperature is 175°C, the screw rotation speed is 200 r / min, the feeding rate is 30 r / min, the extruded melt is cut into particles after water cooling and air drying to obtain composite particles;

[0058] The above composite particles are added into an injection molding machine for injection molding, barrel temperature: 175℃ for zone 1, 185℃ for zone 2, 195℃ for zone 3, nozzle temperature 190℃, mold temperature 50℃, clamping force 800kN, injection pressure 80MPa, packing pressure 60MPa, packing time 15s, cooling time 30s, to obtain a molded turnover box;

[0059] The above molded turnover box is treated at 110℃ for 30min, and naturally cooled to room temperature to obtain a low-temperature-resistant turnover box.

[0060] A method for preparing a low-temperature-resistant turnover box, comprising at least the following steps:

[0061] 70 parts by mass of polypropylene (SP179), 10 parts by mass of the modified nucleating agent prepared in Example 2, 25 parts by mass of the amine-modified ternary ethylene-propylene rubber prepared in Example 3, 0.2 parts by mass of a erucamide lubricant, 0.1 parts by mass of antioxidant 1010, 0.1 parts by mass of antioxidant 168, 0.3 parts by mass of polyethylene wax, and 4 parts by mass of titanium white are added into a high-speed mixer, mixed at 65℃ and 1000r / min for 8min to obtain a premix;

[0062] The premix is put into a twin-screw extruder for melt blending and granulation, the temperature of each zone of the extruder: 165℃ for zone 1, 175℃ for zone 2, 185℃ for zone 3, 180℃ for zone 4, die temperature 175℃, screw rotation speed 200r / min, feeding rate 30r / min, and the extruded melt is cut into particles after water cooling and air drying to obtain composite particles;

[0063] The above composite particles are added into an injection molding machine for injection molding, barrel temperature: 175℃ for zone 1, 185℃ for zone 2, 195℃ for zone 3, nozzle temperature 190℃, mold temperature 50℃, clamping force 800kN, injection pressure 80MPa, packing pressure 60MPa, packing time 15s, cooling time 30s, to obtain a molded turnover box;

[0064] The above molded turnover box is treated at 110℃ for 30min, and naturally cooled to room temperature to obtain a low-temperature-resistant turnover box.

[0065] Comparative Example 1, compared with Example 4, replaces the modified nucleating agent prepared in Example 1 with a physical mixture of 3.5 parts by mass of graft copolymer, 0.32 parts by mass of β nucleating agent (TMB-5), and 3.2 parts by mass of anhydrous calcium sulfate whisker in Example 1, and the remaining components and preparation method are completely consistent with Example 4.

[0066] Comparative Example 2 Compared with Example 4, Comparative Example 2 only replaces the modified nucleating agent prepared in Example 1 added in Example 4 with the same mass of unmodified β nucleating agent (TMB-5) in Example 1, and the rest of the components and preparation methods are completely consistent with Example 4.

[0067] Comparative Example 3 Compared with Example 4, Comparative Example 3 only replaces the modified nucleating agent prepared in Example 1 added in Example 4 with the same mass of whisker-loaded β nucleating agent prepared in Example 1, and the rest of the components and preparation methods are completely consistent with Example 4.

[0068] Comparative Example 4 Compared with Example 4, Comparative Example 4 only replaces the amine-based EPDM prepared in Example 3 added in Example 4 with the same mass of unmodified EPDM in Example 3, and the rest of the components and preparation methods are completely consistent with Example 4.

[0069] Performance test

[0070] Impact performance test: determined according to GB / T 1843 standard. The impact test selects the cantilever beam mode. The impact test sample size is 80mmx10mmx4mm (notch depth 2mm). All components are repeated at least 5 times and averaged. The low-temperature impact test is completed within 5 seconds after being taken out from the high-low temperature oven at -50℃ for 6h, and the other conditions remain unchanged; the test results are shown in Table 1.

[0071] Tensile performance test: according to GB / T 1040 standard. The tensile test sample size is 150mmx10mmx4mm. All components are repeated at least 5 times and averaged; the test results are shown in Table 1.

[0072] Low-temperature falling ball impact test: in order to obtain a lower temperature for the material, the liquid nitrogen freezing method is used for cooling. First, the sample is soaked in liquid nitrogen for ten minutes, then taken out and placed at room temperature for 25s, and finally the falling ball impact test device is used to impact the sample with steel balls of 0.5kg and 1kg at different heights until it breaks, at which time the corresponding low-temperature impact grade is obtained, wherein, first grade: weight 0.5kg, height 0.35m, second grade: weight 0.5kg, height 0.60m, third grade: weight 0.5kg, height 0.85m, fourth grade: weight 0.5kg, height 1.10m, fifth grade: weight 1kg, height 0.60m, sixth grade: weight 1kg, height 0.55m, seventh grade: weight 1kg, height 1.10m, eighth grade: unbroken; the test results are shown in Table 1.

[0073] Table 1: Performance test data statistics table of turnover box in Examples 4-7 and Comparative Examples 1-4

[0074] Room temperature impact (KJ / m 2 ) Low temperature impact (KJ / m 2 )]> Tensile strength (MPa) Elongation at break (%) Low temperature impact rating Example 4 52.3 13.3 33.6 420 7 Example 5 50.8 12.5 32.9 410 7 Example 6 48.6 11.4 34.2 390 7 Example 7 47.6 11.2 33.5 380 7 Comparative Example 1 38.2 6.3 29.1 320 4 Comparative Example 2 35.7 5.1 28.3 290 3 Comparative Example 3 41.5 8.7 30.2 350 5 Comparative Example 4 30.4 4.2 29.8 240 2

[0075] As shown in Table 1, the present invention prepared the following by adding a modified nucleating agent and amination-modified EPDM rubber in Examples 4-7: Figure 1 The low-temperature resistant turnover box shown maintains high impact strength even at extreme low temperatures of -50℃, without any reduction in tensile strength, achieving a balance of "low-temperature resistance, high impact, and high rigidity," meeting the demands of harsh scenarios such as cold chain logistics and high-altitude cold regions. In Comparative Example 1, the physical mixing of graft copolymer, nucleating agent, and whiskers resulted in a slight decrease in the various properties of the turnover box, indicating that chemical bonding can significantly improve dispersibility and interfacial transfer efficiency. In Comparative Example 2, the nucleating agent was not loaded with whiskers, resulting in a significant decrease in low-temperature impact performance, indicating that the pure nucleating agent has limited effect on improving the nucleation efficiency of polypropylene. In Comparative Example 3, the nucleating agent loaded with whiskers was not added to the graft copolymer, and the turnover box's various properties were better than those of Comparative Example 2, indicating that whisker loading can improve the dispersibility of the nucleating agent and increase nucleation efficiency. In Comparative Example 4, the EPDM rubber was not amination-treated, resulting in a significant decrease in the low-temperature impact rating, indicating that amination can enhance interfacial bonding, allowing the elastic micro-regions to absorb impact energy more efficiently.

[0076] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A low temperature resistant tote, characterized in that, At least comprising the following raw materials by mass fraction: Polypropylene 60-70 parts by mass; modified nucleating agent 5-10 parts by mass; amine-based ethylene-propylene-diene rubber 15-25 parts by mass; lubricant 0.2-1 part by mass; processing aid 0.5-1 part by mass; pigment 1-4 parts by mass; The preparation method of the modified nucleating agent comprises the following steps: The xylene and polypropylene are heated and mixed, the dicumyl peroxide solution in xylene is added, and then the glycidyl methacrylate solution in xylene is added dropwise for reaction, and then the grafted copolymer is obtained after settling and drying; The β nucleating agent and calcium sulfate whisker are dispersed in anhydrous ethanol and ultrasonically treated, and then the activated whisker-loaded β nucleating agent is obtained after suction filtration and drying; The whisker-loaded β nucleating agent, γ-aminopropyl triethoxysilane, anhydrous ethanol and deionized water are mixed, stirred and reacted, filtered and dried to obtain the activated whisker-loaded β nucleating agent; The grafted copolymer and the activated whisker-loaded β nucleating agent are pre-mixed in a high-speed mixer, and then melt blended to obtain the modified nucleating agent; The preparation method of the amine-based ethylene-propylene-diene rubber comprises the following steps: The ethylene-propylene-diene rubber solution in ethyl acetate and the mercaptoethylamine solution in ethyl acetate are mixed, anisole is added, and then the amine-based ethylene-propylene-diene rubber is obtained after ultraviolet irradiation, flocculation and drying.

2. The low temperature resistant shipping container of claim 1, wherein, The mass ratio of the glycidyl methacrylate to the polypropylene is 0.15:1-0.25:1, and the mass ratio of the β nucleating agent to the calcium sulfate whisker is 1:8-1:

12.

3. The low temperature resistant shipping container of claim 1, wherein, The mass ratio of the whisker-loaded β nucleating agent to the γ-aminopropyl triethoxysilane is 20:1-22:1, and the mass ratio of the grafted copolymer to the activated whisker-loaded β nucleating agent is 1:0.8-1:1.

2.

4. The low temperature resistant shipping container of claim 1, wherein, The mass ratio of the ethylene-propylene-diene rubber, the mercaptoethylamine and the anisole is 1:0.4-0.6:0.01-0.

02.

5. The low temperature resistant shipping container of claim 1, wherein, The processing aid is any one or mixture of several of antioxidant 1010, antioxidant 168, polyethylene wax, ethylene bis-stearamide or calcium stearate, the pigment is any one or mixture of several of inorganic pigment or organic pigment, and the lubricant is selected from any one or several of silicone lubricant or erucamide lubricant.

6. A method of manufacturing a low-temperature-resistant shipping box according to any one of claims 1 to 5, characterized in that, At least comprising the following steps: The polypropylene, the modified nucleating agent, the amine-based ethylene-propylene-diene rubber, the lubricant, the processing aid and the pigment are added to a high-speed mixer to obtain a pre-mixture; The pre-mixture is put into a twin-screw extruder for melt blending, granulation, extrusion, cooling and pelletization to obtain a composite particle; The composite particle is added to an injection molding machine for injection molding to obtain a molded turnover box; The molded turnover box is heat treated to obtain a low-temperature-resistant turnover box.

7. The method for preparing a low-temperature resistant turnover box according to claim 6, characterized in that, The temperature of the double screw extruder is set to be 160-170℃ for the first zone, 170-180℃ for the second zone, 180-190℃ for the third zone, 175-185℃ for the fourth zone, and the temperature of the head is 170-180℃; the temperature of the injection molding machine is set to be 170-180℃ for the first zone, 180-190℃ for the second zone, 190-200℃ for the third zone, the nozzle temperature is 185-195℃, and the mold temperature is 40-60℃; the temperature of the heat treatment is 100-110℃, and the time is 30-40min.

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