Polypropylene sling for bag and its preparation process

Abstract

This invention relates to the field of polypropylene sling technology, specifically to a polypropylene sling for FIBCs (Flexible Intermediate Bulk Containers) and its preparation process. The invention involves blending modified polypropylene and modified nano-titanium dioxide for 10-20 minutes at a blending temperature of 130-140°C, then adding polypropylene, high-density polyethylene, talc, compatibilizer, lubricant, and antioxidant and mixing thoroughly to obtain a mixture. This mixture is then poured into an extruder, melt-extruded into a film, cut into filaments, stretched, and heat-set to form raw filaments. These raw filaments are then woven into slings using a sling machine to obtain the polypropylene sling for FIBCs. The polypropylene sling for FIBCs prepared by this invention not only possesses excellent mechanical properties but also excellent aging resistance.

Description

Technical Field

[0001] This invention relates to the field of polypropylene sling technology, specifically to a polypropylene sling for container bags and its preparation process. Background Technology

[0002] With the rapid development of the global logistics industry, the demand for FIBCs (Flexible Intermediate Bulk Containers) continues to rise as the core packaging tool for transporting bulk materials. Polypropylene (PP) slings, due to their advantages such as being lightweight, corrosion-resistant, and inexpensive, have become a key component of the load-bearing structure of FIBCs.

[0003] Polypropylene (PP) is one of the most widely used general-purpose plastics due to its low price and good performance. However, the tertiary carbon atoms in its molecular chain structure are highly susceptible to thermo-oxidative degradation and photo-aging degradation under oxygen, heat, and ultraviolet light conditions, resulting in poor anti-aging properties. When exposed to outdoor environments, its service life is significantly shortened, limiting its application range. While traditional organic anti-aging agents have excellent effects, most are small molecules with poor thermal stability and are not resistant to high temperatures. They are also prone to denaturation and migration during processing and use, which is detrimental to their application in polymer materials such as PP.

[0004] Therefore, we propose a polypropylene sling for container bags and its preparation process. Summary of the Invention

[0005] The purpose of this invention is to provide a polypropylene sling for container bags and its preparation process, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A polypropylene sling for container bags comprises the following components by weight: 90-100 parts polypropylene, 20-30 parts high-density polyethylene, 5-10 parts modified polypropylene, 10-20 parts modified nano titanium dioxide, 5-15 parts talc, 3-5 parts compatibilizer, 3-8 parts lubricant, and 0.1-1.0 parts antioxidant.

[0008] Furthermore, the method for preparing the modified polypropylene is as follows:

[0009] Polypropylene grafted with glycidyl methacrylate, N-(4-aminophenyl)maleimide and toluene was mixed evenly and stirred at room temperature for 22-24 hours. After filtration, washing and drying, modified polypropylene was obtained.

[0010] Further, the mass ratio of the polypropylene grafted with glycidyl methacrylate, N-(4-aminophenyl)maleimide and toluene is 1:(0.2-0.5):(5-10).

[0011] Furthermore, the preparation method of the modified nano-titanium dioxide is as follows:

[0012] Step 1: Mix maleic anhydride-modified tea polyphenols and ethanol evenly, add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide, react for 1-2 hours, then add furfurylamine, reflux at 80-85℃ for 5-7 hours, cool to room temperature, filter, wash and dry to obtain furanyl compound;

[0013] Step 2: Disperse nano-titanium dioxide ultrasonically in a mixed solution of anhydrous ethanol and deionized water, add 3-(isobutenoyloxy)propyltrimethoxysilane and mix well, adjust the pH of the system to 4-5, react at 60-70℃ for 4-6 h, centrifuge, wash and dry to obtain double-bonded titanium dioxide.

[0014] Step 3: Mix double-bonded titanium dioxide, sodium dodecyl sulfate, emulsifier OP-10 and deionized water, and ultrasonically disperse for 0.5-1.0 h. Purge with nitrogen gas, add methyl methacrylate, acrylonitrile, 4-propenoxy-2-hydroxybenzophenone and furanyl compound, heat to 65-75℃, add potassium persulfate, react for 4-6 h, filter, wash and dry to obtain modified nano titanium dioxide.

[0015] Furthermore, in step one, the mass ratio of maleic anhydride-modified tea polyphenols, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide is 1:(0.1-0.2):(0.08-0.10).

[0016] Furthermore, the mass ratio of the maleic anhydride-modified tea polyphenols, furfurylamine, and ethanol is 1:(2-4):(10-12).

[0017] Further, the preparation steps of the maleic anhydride modified tea polyphenol are as follows: tea polyphenols and ethyl acetate are mixed evenly, maleic anhydride and pyridine are added, and the mixture is reacted at 45-55℃ for 5-7 hours. After vacuum rotary evaporation, recrystallization and freeze drying, maleic anhydride modified tea polyphenols are obtained.

[0018] In the above technical solution, tea polyphenols, as a natural antioxidant and antibacterial agent, are modified by grafting maleic anhydride to introduce active double bonds into the tea polyphenol molecule, thereby improving its stability and significantly enhancing the antioxidant properties of plastics, thus extending the service life of plastic products. Simultaneously, the antibacterial properties of tea polyphenols can endow polypropylene materials with antibacterial functions.

[0019] Further, the mass ratio of tea polyphenols, ethyl acetate, maleic anhydride and pyridine is 1:(40-50):(0.5-1.0):(0.3-0.5).

[0020] Furthermore, in step two, the mass ratio of nano-titanium dioxide, anhydrous ethanol, deionized water and 3-(isobutyryloxy)propyltrimethoxysilane is 1:(15-20):(3-5):(1-3).

[0021] Further, in step three, the modified nano-titanium dioxide is composed of the following components in parts by weight: 10-20 parts of double-bonded titanium dioxide, 1-2 parts of sodium dodecyl sulfate, 0.1-0.5 parts of emulsifier OP-10, 200-500 parts of deionized water, 10-15 parts of methyl methacrylate, 15-20 parts of acrylonitrile, 1-5 parts of 4-propenoxy-2-hydroxybenzophenone, 5-10 parts of furanyl compound, and 1-5 parts of potassium persulfate.

[0022] Furthermore, the compatibilizer is one or more of polypropylene grafted with maleic anhydride and polyethylene grafted with maleic anhydride, or a mixture thereof.

[0023] Furthermore, the lubricant is one or a mixture of polypropylene wax, polyethylene wax, silicone masterbatch, polytetrafluoroethylene, and paraffin powder.

[0024] Furthermore, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, and antioxidant BHT246.

[0025] A process for preparing polypropylene lifting straps for container bags includes the following steps:

[0026] Modified polypropylene and modified nano-titanium dioxide are blended for 10-20 minutes at a blending temperature of 130-140℃. Then, polypropylene, high-density polyethylene, talc, compatibilizer, lubricant, and antioxidant are added and mixed evenly to obtain a mixture. The mixture is poured into an extruder, melt-extruded into a film, cut into filaments, stretched, and heat-set to form raw filaments. These raw filaments are then woven into straps using a strapping machine to obtain polypropylene straps for container bags.

[0027] Furthermore, the temperatures of the first, second, third, and fourth temperature control zones of the extruder are 180±20℃, 200±20℃, 220±20℃, and 240±20℃, respectively, the die temperature is 220±20℃, and the screw speed is 20-60 r / min.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The present invention discloses a polypropylene sling for container bags and its preparation process, which successfully obtains modified polypropylene containing maleimide groups by reacting the epoxy groups in glycidyl methacrylate grafted onto polypropylene with the amino groups in N-(4-aminophenyl)maleimide, providing dynamic crosslinking sites for subsequent Diels-Alder reactions.

[0030] In this scheme, an EDC / NHS coupling system is used to promote the reaction between the carboxyl groups in maleic anhydride-modified tea polyphenols and furfurylamine, introducing furan groups to obtain furanyl compounds. Simultaneously, 3-(isobutenoyloxy)propyltrimethoxysilane is used to modify the surface of nano-titanium dioxide, introducing double bonds. Finally, using a free radical copolymerization method, methyl methacrylate (MMA), acrylonitrile (AN), 4-propenoxy-2-hydroxybenzophenone (AHB), and furanyl compounds are copolymerized and coated onto the surface of the nano-titanium dioxide to form an organic layer. This process improves the compatibility and dispersibility of acrylonitrile in polypropylene (PP) matrix, reduces agglomeration, and thus enhances the material's mechanical properties, UV aging resistance, and oxidation resistance. The UV absorption characteristics of acrylonitrile itself, along with the synergistic effect of UV absorbers 4-propenoxy-2-hydroxybenzophenone and furanyl compounds, jointly improve the material's UV resistance and oxidation resistance. The introduction of furanyl compounds allows for a Diels-Alder reaction with maleimide in modified polypropylene, significantly improving the material's heat resistance and thermal stability. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In this embodiment, polypropylene grafted with glycidyl methacrylate: grade D502, sourced from Dongguan Kadar Plastic Raw Materials Co., Ltd.; polypropylene: model R701 (Korea Hyosung); nano titanium dioxide: rutile type, particle size 20-50nm, sourced from Bohuas Nanotechnology; talc powder: particle size 5000 mesh, sourced from Jiangyin Guangyuan Ultrafine Powder Co., Ltd.; compatibilizer: polypropylene grafted with maleic anhydride, grade Exxelor PO 1020 (Exxon); lubricant: polyethylene wax, model Honeywell AC-6A; antioxidant: model Antioxidant 1010.

[0033] Unless otherwise specified, all the following quantities are parts by weight.

[0034] Example 1: A manufacturing process for polypropylene slings for container bags, comprising the following steps:

[0035] Five parts of modified polypropylene and ten parts of modified nano-titanium dioxide were blended for 10 minutes at a blending temperature of 130°C. Then, 90 parts of polypropylene, 20 parts of high-density polyethylene, five parts of talc, three parts of compatibilizer, three parts of lubricant, and 0.1 parts of antioxidant were added and mixed evenly to obtain a mixture. The mixture was poured into an extruder, melt-extruded into a film, cut into filaments, stretched, and heat-set to form raw filaments. These filaments were then woven into straps using a strapping machine to obtain polypropylene straps for container bags. The temperatures of the first, second, third, and fourth temperature control zones of the extruder were 180°C, 200°C, 220°C, and 240°C, respectively, the die temperature was 220°C, and the screw speed was 50 r / min.

[0036] The preparation method of modified polypropylene is as follows:

[0037] Five parts of polypropylene grafted with glycidyl methacrylate, one part of N-(4-aminophenyl)maleimide and 25 parts of toluene were mixed evenly, stirred at room temperature for 22 hours, filtered, washed and dried to obtain modified polypropylene.

[0038] The preparation method of modified nano-titanium dioxide is as follows:

[0039] Step 1: Mix 5 parts of tea polyphenols and 200 parts of ethyl acetate evenly, add 2.5 parts of maleic anhydride and 1.5 parts of pyridine, react at 45℃ for 5 hours, evaporate under reduced pressure, recrystallize, and freeze dry to obtain maleic anhydride modified tea polyphenols.

[0040] Five parts of maleic anhydride-modified tea polyphenols and 50 parts of ethanol were mixed evenly, and 0.5 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.4 parts of N-hydroxysuccinimide were added. The mixture was reacted for 1 hour, and then 10 parts of furfurylamine were added. The mixture was refluxed at 80°C for 5 hours. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain furanyl compounds.

[0041] Step 2: Disperse 10 parts of nano-titanium dioxide ultrasonically in a mixed solution of 150 parts of anhydrous ethanol and 30 parts of deionized water, add 10 parts of 3-(isobutenoyloxy)propyltrimethoxysilane and mix well, adjust the pH of the system to 4, react at 60℃ for 4 h, centrifuge, wash and dry to obtain double-bonded titanium dioxide.

[0042] Step 3: Mix 10 parts of double-bonded titanium dioxide, 1 part of sodium dodecyl sulfate, 0.1 parts of emulsifier OP-10 and 200 parts of deionized water, sonicate for 0.5 h, introduce nitrogen gas, add 10 parts of methyl methacrylate, 15 parts of acrylonitrile, 1 part of 4-propenoxy-2-hydroxybenzophenone and 5 parts of furanyl compound, heat to 65℃, add 1 part of potassium persulfate, react for 4 h, filter, wash and dry to obtain modified nano titanium dioxide.

[0043] Example 2: A process for preparing polypropylene slings for container bags, comprising the following steps:

[0044] Eight parts of modified polypropylene and 15 parts of modified nano-titanium dioxide were blended for 15 minutes at a blending temperature of 135℃. Then, 95 parts of polypropylene, 25 parts of high-density polyethylene, 10 parts of talc, 4 parts of compatibilizer, 6 parts of lubricant, and 0.5 parts of antioxidant were added and mixed evenly to obtain a mixture. The mixture was poured into an extruder, melt-extruded into a film, cut into filaments, stretched and heat-set to form raw filaments, and woven into filaments by a filament weaving machine to obtain polypropylene filament filaments for FIBCs (Flexible Intermediate Bulk Containers). The temperatures of the first, second, third, and fourth temperature control zones of the extruder were 180℃, 200℃, 220℃, and 240℃, respectively, the die temperature was 220℃, and the screw speed was 50 r / min.

[0045] The preparation method of modified polypropylene is as follows:

[0046] Eight parts of polypropylene grafted with glycidyl methacrylate, 2.4 parts of N-(4-aminophenyl)maleimide and toluene were mixed evenly, stirred at room temperature for 23 hours, filtered, washed and dried to obtain modified polypropylene.

[0047] The preparation method of modified nano-titanium dioxide is as follows:

[0048] Step 1: Mix 3 parts of tea polyphenols and 135 parts of ethyl acetate evenly, add 2.4 parts of maleic anhydride and 1.2 parts of pyridine, react at 50℃ for 6 hours, evaporate under reduced pressure, recrystallize, and freeze dry to obtain maleic anhydride modified tea polyphenols.

[0049] Three parts of maleic anhydride-modified tea polyphenols and 33 parts of ethanol were mixed evenly, and 0.45 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.27 parts of N-hydroxysuccinimide were added. The mixture was reacted for 1.5 h, and then 9 parts of furfurylamine were added. The mixture was refluxed at 82 °C for 6 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain furanyl compounds.

[0050] Step 2: Disperse 15 parts of nano-titanium dioxide ultrasonically in a mixed solution of 270 parts of anhydrous ethanol and 60 parts of deionized water, add 30 parts of 3-(isobutenoyloxy)propyltrimethoxysilane and mix evenly. Adjust the pH of the system to 4.5 and react at 65℃ for 5 hours. After centrifugation, washing and drying, double-bonded titanium dioxide is obtained.

[0051] Step 3: Mix 15 parts of double-bonded titanium dioxide, 1.5 parts of sodium dodecyl sulfate, 0.3 parts of emulsifier OP-10 and 400 parts of deionized water, sonicate for 0.8 h, introduce nitrogen gas, add 12 parts of methyl methacrylate, 18 parts of acrylonitrile, 3 parts of 4-propenoxy-2-hydroxybenzophenone and 8 parts of furanyl compound, heat to 70℃, add 3 parts of potassium persulfate, react for 5 h, filter, wash and dry to obtain modified nano titanium dioxide.

[0052] Example 3: A process for preparing polypropylene slings for container bags, comprising the following steps:

[0053] 10 parts modified polypropylene and 20 parts modified nano titanium dioxide were blended for 20 minutes at a blending temperature of 140℃. Then, 100 parts polypropylene, 30 parts high-density polyethylene, 15 parts talc, 5 parts compatibilizer, 8 parts lubricant, and 1.0 part antioxidant were added and mixed evenly to obtain a mixture. The mixture was poured into an extruder, melt-extruded into a film, cut into filaments, stretched and heat-set to form raw filaments, and woven into filaments by a filament weaving machine to obtain polypropylene filament filaments for container bags. The temperatures of the first, second, third, and fourth temperature control zones of the extruder were 180℃, 200℃, 220℃, and 240℃, respectively, the die temperature was 220℃, and the screw speed was 50 r / min.

[0054] The preparation method of modified polypropylene is as follows:

[0055] 10 parts of polypropylene grafted with glycidyl methacrylate, 5 parts of N-(4-aminophenyl)maleimide and 100 parts of toluene were mixed evenly, stirred at room temperature for 24 hours, filtered, washed and dried to obtain modified polypropylene.

[0056] The preparation method of modified nano-titanium dioxide is as follows:

[0057] Step 1: Mix 3 parts of tea polyphenols and 150 parts of ethyl acetate evenly, add 3 parts of maleic anhydride and 1.5 parts of pyridine, react at 55℃ for 7 hours, evaporate under reduced pressure, recrystallize, and freeze dry to obtain maleic anhydride modified tea polyphenols.

[0058] Three parts of maleic anhydride-modified tea polyphenols and 36 parts of ethanol were mixed evenly, and 0.6 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.3 parts of N-hydroxysuccinimide were added. The mixture was reacted for 2 hours, and then 12 parts of furfurylamine were added. The mixture was refluxed at 85°C for 7 hours. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain furanyl compounds.

[0059] Step 2: Disperse 20 parts of nano-titanium dioxide ultrasonically in a mixed solution of 400 parts of anhydrous ethanol and 100 parts of deionized water, add 60 parts of 3-(isobutenoyloxy)propyltrimethoxysilane and mix evenly. Adjust the pH of the system to 5, react at 70℃ for 6 hours, and after centrifugation, washing and drying, obtain double-bonded titanium dioxide.

[0060] Step 3: Mix 20 parts of double-bonded titanium dioxide, 2 parts of sodium dodecyl sulfate, 0.5 parts of emulsifier OP-10 and 500 parts of deionized water, and ultrasonically disperse for 1.0 h. Purge with nitrogen gas, add 15 parts of methyl methacrylate, 20 parts of acrylonitrile, 5 parts of 4-propenoxy-2-hydroxybenzophenone and 10 parts of furanyl compound, heat to 75℃, add 5 parts of potassium persulfate, react for 6 h, filter, wash and dry to obtain modified nano titanium dioxide.

[0061] Comparative Example 1: A manufacturing process for polypropylene slings for container bags, comprising the following steps:

[0062] Example 2 was used as the control group, and Comparative Example 1 did not add modified polypropylene, while the other steps were the same as in Example 2.

[0063] Comparative Example 2: A manufacturing process for a polypropylene sling for a container bag, comprising the following steps:

[0064] Example 2 was used as the control group. In Comparative Example 2, the modified nano-titanium dioxide was replaced with the same mass of nano-titanium dioxide, and the other steps were the same as in Example 2.

[0065] Comparative Example 3: A manufacturing process for a polypropylene sling for a container bag, comprising the following steps:

[0066] The preparation method of modified nano-titanium dioxide is as follows:

[0067] Step 1: Mix 3 parts of tea polyphenols and 135 parts of ethyl acetate evenly, add 2.4 parts of maleic anhydride and 1.2 parts of pyridine, react at 50℃ for 6 hours, evaporate under reduced pressure, recrystallize, and freeze dry to obtain maleic anhydride modified tea polyphenols.

[0068] Three parts of maleic anhydride-modified tea polyphenols and 33 parts of ethanol were mixed evenly, and 0.45 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.27 parts of N-hydroxysuccinimide were added. The mixture was reacted for 1.5 h, and then 9 parts of furfurylamine were added. The mixture was refluxed at 82 °C for 6 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain furanyl compounds.

[0069] Step 2: Disperse 15 parts of nano-titanium dioxide ultrasonically in a mixed solution of 270 parts of anhydrous ethanol and 60 parts of deionized water, add 30 parts of 3-(isobutenoyloxy)propyltrimethoxysilane and mix evenly. Adjust the pH of the system to 4.5 and react at 65℃ for 5 hours. After centrifugation, washing and drying, double-bonded titanium dioxide is obtained.

[0070] Step 3: Mix 15 parts of double-bonded titanium dioxide, 1.5 parts of sodium dodecyl sulfate, 0.3 parts of emulsifier OP-10 and 400 parts of deionized water, ultrasonically disperse for 0.8 h, introduce nitrogen gas, add 12 parts of methyl methacrylate, 18 parts of acrylonitrile and 3 parts of 4-propenoxy-2-hydroxybenzophenone, heat to 70℃, add 3 parts of potassium persulfate, react for 5 h, filter, wash and dry to obtain modified nano titanium dioxide;

[0071] Example 2 was used as the control group, and Comparative Example 3 was performed without the addition of furanyl compounds, with the other steps being the same as in Example 2.

[0072] Comparative Example 4: A manufacturing process for a polypropylene sling for a container bag, comprising the following steps:

[0073] The preparation method of modified nano-titanium dioxide is as follows:

[0074] Step 1: Mix 3 parts of tea polyphenols and 135 parts of ethyl acetate evenly, add 2.4 parts of maleic anhydride and 1.2 parts of pyridine, react at 50℃ for 6 hours, evaporate under reduced pressure, recrystallize, and freeze dry to obtain maleic anhydride modified tea polyphenols.

[0075] Three parts of maleic anhydride-modified tea polyphenols and 33 parts of ethanol were mixed evenly, and 0.45 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.27 parts of N-hydroxysuccinimide were added. The mixture was reacted for 1.5 h, and then 9 parts of furfurylamine were added. The mixture was refluxed at 82 °C for 6 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain furanyl compounds.

[0076] Step 2: Disperse 15 parts of nano-titanium dioxide ultrasonically in a mixed solution of 270 parts of anhydrous ethanol and 60 parts of deionized water, add 30 parts of 3-(isobutenoyloxy)propyltrimethoxysilane and mix evenly. Adjust the pH of the system to 4.5 and react at 65℃ for 5 hours. After centrifugation, washing and drying, double-bonded titanium dioxide is obtained.

[0077] Step 3: Mix 15 parts of double-bonded titanium dioxide, 1.5 parts of sodium dodecyl sulfate, 0.3 parts of emulsifier OP-10 and 400 parts of deionized water, sonicate for 0.8 h, introduce nitrogen gas, add 12 parts of methyl methacrylate, 18 parts of acrylonitrile and 8 parts of furanyl compound, heat to 70℃, add 3 parts of potassium persulfate, react for 5 h, filter, wash and dry to obtain modified nano titanium dioxide;

[0078] Compared with Example 2, Comparative Example 4 did not add 4-propenoxy-2-hydroxybenzophenone, and the other steps were the same as in Example 2.

[0079] Testing experiment:

[0080] 1. Tensile property test: The films obtained in Examples 1-3 and Comparative Examples 1-4 were tested in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3 Test conditions for films and sheets" with a tensile rate of 10 mm / min.

[0081] 2. Xenon lamp aging test: Referring to the standard GB / T 16422.2-2014, a xenon lamp was used as the light source, with an irradiance of 0.51 W / m². 2 The black standard temperature was cycled at 65℃ and 100℃, with an exposure cycle of 102 min drying and 18 min spraying, and a test time of 120 h. The tensile strength before and after aging was measured, and the change rate of tensile strength was calculated.

[0082] The test results are as follows:

[0083] Tensile strength / MPa Tensile strength retention rate / % Example 1 43.4 77.9 Example 2 45.5 80.4 Example 3 44.8 78.5 Comparative Example 1 38.7 70.2 Comparative Example 2 36.0 58.7 Comparative Example 3 40.6 62.8 Comparative Example 4 42.3 64.5

[0084] Based on the data in the table above, the following conclusions can be clearly drawn:

[0085] Data from Examples 1-3 show that the present invention improves the tensile strength and aging resistance of the material by introducing modified polypropylene and modified nano-titanium dioxide. Data from Examples 2 and Comparative Example 1 show that, in Comparative Example 1 without the introduction of modified polypropylene, the tensile strength and tensile retention of the material are significantly reduced. Data from Examples 2 and Comparative Example 1 show that, compared with nano-titanium dioxide, the modified nano-titanium dioxide prepared by the present invention has better compatibility and aging resistance. Data from Examples 2 and Comparative Examples 3-4 show that, in Comparative Example 3 without the introduction of furanyl compounds, the lack of dynamic crosslinking sites leads to a significant decrease in aging resistance and thermal stability. In Comparative Example 4 without the introduction of 4-propenoxy-2-hydroxybenzophenone, the UV resistance is reduced, resulting in a decrease in the aging resistance of the material.

[0086] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A polypropylene sling for container bags, characterized in that: It includes the following components by weight: 90-100 parts polypropylene, 20-30 parts high-density polyethylene, 5-10 parts modified polypropylene, 10-20 parts modified nano titanium dioxide, 5-15 parts talc, 3-5 parts compatibilizer, 3-8 parts lubricant, and 0.1-1.0 parts antioxidant. The modified polypropylene is prepared by: Polypropylene grafted with glycidyl methacrylate, N-(4-aminophenyl)maleimide and toluene was mixed evenly, stirred at room temperature for 22-24 h, filtered, washed and dried to obtain modified polypropylene. The preparation method of the modified nano-titanium dioxide is as follows: Step 1: Mix maleic anhydride-modified tea polyphenols and ethanol evenly, add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide, react for 1-2 hours, then add furfurylamine, reflux at 80-85℃ for 5-7 hours, cool to room temperature, filter, wash and dry to obtain furanyl compound; Step 2: Disperse nano-titanium dioxide ultrasonically in a mixed solution of anhydrous ethanol and deionized water, add 3-(isobutenoyloxy)propyltrimethoxysilane and mix well, adjust the pH of the system to 4-5, react at 60-70℃ for 4-6 h, centrifuge, wash and dry to obtain double-bonded titanium dioxide. Step 3: Mix double-bonded titanium dioxide, sodium dodecyl sulfate, emulsifier OP-10 and deionized water, and ultrasonically disperse for 0.5-1.0 h. Purge with nitrogen gas, add methyl methacrylate, acrylonitrile, 4-propenoxy-2-hydroxybenzophenone and furanyl compound, heat to 65-75℃, add potassium persulfate, react for 4-6 h, filter, wash and dry to obtain modified nano titanium dioxide.

2. The polypropylene sling for container bags according to claim 1, characterized in that: The mass ratio of maleic anhydride-modified tea polyphenols, furfurylamine, and ethanol is 1:(2-4):(10-12).

3. The polypropylene sling for container bags according to claim 1, characterized in that: The preparation steps of the maleic anhydride modified tea polyphenol are as follows: tea polyphenols and ethyl acetate are mixed evenly, maleic anhydride and pyridine are added, and the mixture is reacted at 45-55℃ for 5-7 hours. After rotary evaporation under reduced pressure, recrystallization, and freeze drying, maleic anhydride modified tea polyphenols are obtained.

4. The polypropylene sling for container bags according to claim 1, characterized in that: In step two, the mass ratio of nano-titanium dioxide, anhydrous ethanol, deionized water and 3-(isobutenoyloxy)propyltrimethoxysilane is 1:(15-20):(3-5):(1-3).

5. A polypropylene sling for a container bag according to claim 1, characterized in that: In step three, the modified nano-titanium dioxide is composed of the following components in parts by weight: 10-20 parts of double-bonded titanium dioxide, 1-2 parts of sodium dodecyl sulfate, 0.1-0.5 parts of emulsifier OP-10, 200-500 parts of deionized water, 10-15 parts of methyl methacrylate, 15-20 parts of acrylonitrile, 1-5 parts of 4-propenoxy-2-hydroxybenzophenone, 5-10 parts of furanyl compound, and 1-5 parts of potassium persulfate.

6. The polypropylene sling for container bags according to claim 1, characterized in that: The compatibilizer is one or a mixture of polypropylene grafted with maleic anhydride and polyethylene grafted with maleic anhydride.

7. A polypropylene sling for container bags according to claim 1, characterized in that: The lubricant is one or a mixture of polypropylene wax, polyethylene wax, silicone masterbatch, polytetrafluoroethylene, and paraffin powder.

8. The manufacturing process of a polypropylene sling for a container bag according to any one of claims 1-7, characterized in that: Includes the following steps: Modified polypropylene and modified nano-titanium dioxide are blended for 10-20 minutes at a blending temperature of 130-140℃. Then, polypropylene, high-density polyethylene, talc, compatibilizer, lubricant, and antioxidant are added and mixed evenly to obtain a mixture. The mixture is poured into an extruder, melt-extruded into a film, cut into filaments, stretched, and heat-set to form raw filaments. These raw filaments are then woven into straps using a strapping machine to obtain polypropylene straps for container bags.