A transparent polypropylene medical plastic cup and its preparation method

Abstract

The present invention relates to the technical field of plastic cups, and particularly to a transparent polypropylene medical plastic cup and a preparation method thereof. The plastic cup comprises the following weight components: 60-80 parts of polypropylene, 3-8 parts of polyoxymethylene, 5-15 parts of modified nano calcium carbonate, 3-5 parts of kaolin, 2-4 parts of talcum powder, 0.2-0.4 part of nucleating agent, 0.5-1.5 parts of lubricant, 1-3 parts of antioxidant, and 0.5-1.0 part of stabilizer. The present invention obtains a mixture by uniformly stirring polypropylene, polyoxymethylene, modified nano calcium carbonate, kaolin, talcum powder, nucleating agent, lubricant, antioxidant and stabilizer; and performs melt extrusion, granulation and injection molding on the mixture to obtain the plastic cup, which not only has excellent mechanical properties, but also has excellent antibacterial properties and can effectively prevent the growth of bacteria.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic cups, and specifically to a transparent polypropylene medical plastic cup and a preparation method thereof. Background Art

[0002] With the continuous progress of medical technology and the improvement of people's requirements for the quality of medical services, medical plastic products are increasingly widely used in the medical field. Polypropylene (PP) is a light-weight and high-strength thermoplastic with good mechanical properties, chemical corrosion resistance and heat resistance. In addition, polypropylene also has good processing properties and is easy to be formed and processed into products of various shapes and sizes.

[0003] However, the transparency of traditional polypropylene materials is poor, and the transparency of plastic cups made of polypropylene is not good, which limits its application in some places with high requirements for transparency; secondly, due to the tertiary carbon atoms contained in the molecular chain structure of polypropylene, it is extremely easy to generate thermal-oxidative aging degradation and photo-aging degradation under the conditions of oxygen, heat and ultraviolet rays, resulting in poor anti-aging performance. In addition, the deficiency of polypropylene in antibacterial also limits its application in the medical field, because the growth of bacteria and microorganisms on the plastic surface may lead to cross-infection.

[0004] Therefore, we propose a transparent polypropylene medical plastic cup and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a transparent polypropylene medical plastic cup and a preparation method thereof to solve the problems raised in the prior art.

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

[0007] A preparation method of a transparent polypropylene medical plastic cup, comprising the following steps:

[0008] Step S1: Stir polypropylene, polyoxymethylene, modified nano calcium carbonate, kaolin, talc powder, nucleating agent, lubricant, antioxidant and stabilizer evenly to obtain a mixture;

[0009] Step S2: Add the mixture into a twin-screw extruder for melt extrusion, granulation, and injection molding to obtain a plastic cup.

[0010] Further, the plastic cup comprises the following weight components: 60-80 parts of polypropylene, 3-8 parts of polyoxymethylene, 5-15 parts of modified nano calcium carbonate, 3-5 parts of kaolin, 2-4 parts of talc powder, 0.2-0.4 parts of nucleating agent, 0.5-1.5 parts of lubricant, 1-3 parts of antioxidant, and 0.5-1.0 parts of stabilizer.

[0011] Further, the preparation method of the modified nano calcium carbonate is as follows:

[0012] Step (1): Mix nano calcium carbonate, absolute ethanol and deionized water evenly to obtain a mixed solution. Adjust the pH of the system to 9 - 10, heat up to 50 - 70 °C, introduce nitrogen, add vinyltrimethoxysilane, and react for 4 - 6 h. After filtration, washing and drying, vinyl nano calcium carbonate is obtained.

[0013] Step (2): Mix vinyl nano calcium carbonate and deionized water evenly, add methyl methacrylate, methacrylamide and modified tea polyphenols, introduce nitrogen, add potassium persulfate, and react at 70 - 80 °C for 10 - 12 h. After centrifugation, washing and drying, an amino group-containing compound is obtained.

[0014] Step (3): Mix the amino group-containing compound and an aqueous glutaraldehyde solution evenly, stir at 25 - 35 °C for 12 - 14 h. After centrifugation, washing and drying, an aldehyde group-containing compound is obtained; mix chitosan and an acetic acid solution evenly to obtain a chitosan solution, add the aldehyde group-containing compound and sodium borohydride, and react at 20 - 40 °C for 4 - 6 h. After centrifugation, washing and drying, an intermediate is obtained.

[0015] Step (4): Mix the intermediate and isopropanol evenly, add a sodium hydroxide solution to adjust the pH to 9 - 10, add 2,3-epoxypropyltrimethylammonium chloride, and react at 60 - 70 °C for 5 - 7 h. After precipitation, filtration, washing and drying, modified nano calcium carbonate is obtained.

[0016] In the above technical solution, the surface of nano calcium carbonate is modified by vinyltrimethoxysilane to introduce double bonds, and then through free radical copolymerization, methyl methacrylate, methacrylamide and modified tea polyphenols are copolymerized and coated on the surface of nano calcium carbonate to obtain an amino group-containing compound; subsequently, a Schiff base bond is formed by the reaction of the amino group-containing compound and glutaraldehyde to obtain an aldehyde group-containing compound, and a Schiff base reaction occurs between the amino group in chitosan and the aldehyde group to obtain an intermediate; finally, 2,3-epoxypropyltrimethylammonium chloride (GTA) quaternary ammonium salt is grafted onto the C6 hydroxyl group of chitosan to obtain modified nano calcium carbonate.

[0017] Further, in the step (1), the mass ratio of nano calcium carbonate, absolute ethanol, deionized water and vinyltrimethoxysilane is 1:(15 - 20):(3 - 5):(2 - 4).

[0018] Further, in the step (2), the mass ratio of vinyl nano calcium carbonate and deionized water is 1:(50 - 100).

[0019] Further, in the step (2), the mass ratio of vinyl nanometer calcium carbonate, methyl methacrylate, methacrylamide and modified tea polyphenols is 1: (1 - 2): (2 - 4): (0.5 - 1.5).

[0020] Further, the dosage of potassium persulfate is 1 - 3% of the total mass of vinyl nanometer calcium carbonate, methyl methacrylate, methacrylamide and modified tea polyphenols.

[0021] Further, the preparation method of the modified tea polyphenols is as follows:

[0022] Mix tea polyphenols and ethyl acetate evenly, add maleic anhydride and pyridine, react in a water bath shaker at 50 - 70 °C for 5 - 7 h, and obtain modified tea polyphenols after reduced pressure rotary evaporation, recrystallization and freeze drying.

[0023] 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).

[0024] Further, in the step (3), the mass ratio of the amino - containing compound and the aqueous glutaraldehyde solution is 1: (50 - 100), and the concentration of the aqueous glutaraldehyde solution is 25 wt%.

[0025] Further, in the step (3), the mass ratio of chitosan and acetic acid solution is 1: (25 - 50), and the concentration of the acetic acid solution is 1 wt%.

[0026] Further, in the step (3), the mass ratio of chitosan, aldehyde - containing compound and sodium borohydride is 1: (0.2 - 0.6): (0.1 - 0.2).

[0027] Further, in the step (4), the mass ratio of the intermediate, isopropanol and 2,3 - epoxypropyltrimethylammonium chloride is 1: (15 - 30): (3 - 5), and the concentration of the sodium hydroxide solution is 40 wt%.

[0028] Further, the lubricant is polyethylene wax.

[0029] Further, the stabilizer is an organic tin stabilizer.

[0030] Further, the temperatures of each zone of the twin - screw extruder are: zone 1: 178 - 182 °C, zone 2: 188 - 192 °C, zone 3: 198 - 202 °C, zone 4: 208 - 212 °C, zone 5: 220 - 225 °C, die head: 215 - 220 °C; the screw speed is 120 - 180 r / min.

[0031] Furthermore, the injection molding is carried out using an injection molding machine. The length-diameter ratio of the screw of the injection molding machine is 12 - 15, the screw rotation speed is 60 - 80 rpm, the temperature of the feeding section of the injection molding machine is 200 - 250 °C, the temperature of the conveying section is 230 - 260 °C, the temperature of the injection section is 250 - 280 °C, the temperature of the nozzle is 260 - 270 °C, the mold temperature is 70 - 80 °C, the injection pressure is 70 - 100 Mpa, and the back pressure is 1 - 2 Mp.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1. For a transparent polypropylene medical plastic cup and its preparation method of the present invention, maleic anhydride is used as a modifier to prepare modified tea polyphenols, introducing double bonds and improving its stability at the same time. As a natural antioxidant and antibacterial agent, tea polyphenols can significantly enhance the antioxidant performance of plastics, effectively delay the degradation process caused by oxidation, and thus extend the service life of plastic products. At the same time, the antibacterial property of tea polyphenols can endow the polypropylene material with antibacterial function, reducing the growth of bacteria on the plastic surface, and is particularly suitable for sanitary fields such as medical devices and food packaging.

[0034] 2. For a transparent polypropylene medical plastic cup and its preparation method of the present invention, vinyltrimethoxysilane is used to further modify the surface of nano-calcium carbonate, introducing double bonds, and then through free radical copolymerization, methyl methacrylate, methacrylamide and modified tea polyphenols are copolymerized and coated on the surface of nano-calcium carbonate to form an organic layer, which is beneficial to improving its compatibility and dispersibility in the polypropylene matrix (PP), reducing agglomeration, and further improving the mechanical properties, antioxidant properties and antibacterial properties of the material;

[0035] Chitosan is a natural biodegradable material with excellent biocompatibility. Schiff base bonds are formed through the reaction of amino-containing compounds and glutaraldehyde to obtain aldehyde group-containing compounds. The Schiff base reaction occurs between the amino group and aldehyde group in chitosan to obtain an intermediate; finally, 2,3-epoxypropyltrimethylammonium chloride (GTA) quaternary ammonium salt is grafted onto the C6 hydroxyl group of chitosan to obtain modified nano-calcium carbonate, further enhancing the antibacterial property and biocompatibility of the material and extending the service life of the material.

[0036] 3. A transparent polypropylene medical plastic cup and its preparation method according to the present invention use polyoxymethylene (POM) as a modifier to enhance the rigidity and toughness of polypropylene (PP). The POM / PP composite material exhibits good mechanical properties. Modified nano calcium carbonate, kaolin, and talc powder are used as inorganic fillers to effectively improve the mechanical properties of the material, while enhancing the antioxidant and antibacterial properties of the material. Combining the synergistic effects of a nucleating agent, a lubricant, an antioxidant, and a stabilizer, a mixture is obtained; the mixture is added to a twin-screw extruder for melt extrusion and granulation, and then injection molded to obtain a plastic cup, which not only has excellent mechanical properties and transparency, but also has strong antioxidant and antibacterial properties, as well as good thermal stability and processing performance. Detailed implementation mode

[0037] 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 of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] In this embodiment, the polypropylene: the model is Hyosung R701 from South Korea; the polyoxymethylene: the grade is MC90; the nano calcium carbonate: the particle size is 20 nm, sourced from Shanghai Naiou Nano Technology Co., Ltd.; the kaolin: calcined kaolin, the particle size is 4000 mesh, sourced from Guangdong Yuanlei Powder Co., Ltd.; the talc powder: the particle size is 5000 mesh, sourced from Jiangyin Guangyuan Superfine Powder Co., Ltd.; the nucleating agent: the model is Millad NX8000i; the lubricant: polyethylene wax, the model is Honeywell AC-6A; the antioxidant: the model is antioxidant 1010; the stabilizer: the model is TM-181FS.

[0039] In the following examples and comparative examples, 1 part is equal to 10 g.

[0040] Example 1: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0041] Step S1: Stir 60 parts of polypropylene, 3 parts of polyoxymethylene, 5 parts of modified nano calcium carbonate, 3 parts of kaolin, 2 parts of talc powder, 0.2 part of nucleating agent, 0.5 part of lubricant, 1 part of antioxidant, and 0.5 part of stabilizer evenly to obtain a mixture;

[0042] Step S2: Add the mixture into a twin-screw extruder for melt extrusion (the temperatures of each zone of the twin-screw extruder are: Zone 1: 178°C, Zone 2: 188°C, Zone 3: 198°C, Zone 4: 208°C, Zone 5: 220°C, die head: 215°C; screw speed: 120 r / min), pelletize, and use an injection molding machine for injection molding. The length-diameter ratio of the screw of the injection molding machine is 12, the screw speed is 60 rpm, the temperature of the feeding section of the injection molding machine is 200°C, the temperature of the conveying section is 230°C, the temperature of the injection section is 250°C, the temperature of the nozzle is 260°C, the mold temperature is 70°C, the injection pressure is 70 Mpa, the back pressure is 1 Mp. After cooling and solidifying, open the mold to obtain a plastic cup;

[0043] The preparation method of the modified nano calcium carbonate is as follows:

[0044] Step (1): Mix 5 parts of nano calcium carbonate, 75 parts of absolute ethanol, and 15 parts of deionized water evenly to obtain a mixed solution. Adjust the pH of the system to 9, heat up to 50°C, introduce nitrogen, add 10 parts of vinyltrimethoxysilane, and react for 4 h. After filtration, washing, and drying, vinyl nano calcium carbonate is obtained;

[0045] Step (2): Mix 5 parts of vinyl nano calcium carbonate and 100 parts of deionized water evenly, add 5 parts of methyl methacrylate, 10 parts of methacrylamide, and 2.5 parts of modified tea polyphenols, introduce nitrogen, add 0.225 parts of potassium persulfate, and react at 70°C for 10 h. After centrifugation, washing, and drying, an amino compound-containing product is obtained;

[0046] Step (3): Mix 5 parts of the amino compound-containing product and 250 parts of 25 wt% glutaraldehyde aqueous solution evenly, stir at 25°C for 12 h. After centrifugation, washing, and drying, an aldehyde group-containing compound is obtained; Mix 25 parts of chitosan and 625 parts of 1 wt% acetic acid solution evenly to obtain a chitosan solution. Add 5 parts of the aldehyde group-containing compound and 0.25 parts of sodium borohydride, and react at 30°C for 5 h. After centrifugation, washing, and drying, an intermediate is obtained;

[0047] Step (4): Mix 5 parts of the intermediate and 75 parts of isopropanol evenly, add 40 wt% sodium hydroxide solution to adjust the pH to 9.5, add 15 parts of 2,3-epoxypropyltrimethylammonium chloride, and react at 60°C for 5 h. After precipitation, filtration, washing, and drying, modified nano calcium carbonate is obtained;

[0048] The preparation method of the modified tea polyphenols is as follows:

[0049] Mix 2.5 parts of tea polyphenols and 100 parts of ethyl acetate evenly, add 1.25 parts of maleic anhydride and 0.75 parts of pyridine, and react in a water bath shaker at 50°C for 5 h. After rotary evaporation under reduced pressure, recrystallization, and freeze drying, modified tea polyphenols are obtained.

[0050] Example 2: A preparation method of a transparent polypropylene medical plastic cup, comprising the following processes:

[0051] Step S1: Stir 70 parts of polypropylene, 5 parts of polyoxymethylene, 10 parts of modified nano calcium carbonate, 4 parts of kaolin, 3 parts of talcum powder, 0.3 part of nucleating agent, 1 part of lubricant, 2 parts of antioxidant and 0.8 part of stabilizer evenly to obtain a mixture.

[0052] Step S2: Add the mixture into a twin-screw extruder for melt extrusion (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 223 °C, and the head at 218 °C; the screw speed is 160 r / min), pelletize, and injection molding is carried out using an injection molding machine. The length-diameter ratio of the screw of the injection molding machine is 14, the screw speed is 70 rpm, the temperature of the feeding section of the injection molding machine is 230 °C, the temperature of the feeding section is 250 °C, the temperature of the injection section is 260 °C, the temperature of the nozzle is 265 °C, the mold temperature is 75 °C, the injection pressure is 80 Mpa, the back pressure is 1.5 Mp. After cooling and solidifying, open the mold to obtain a plastic cup.

[0053] The preparation method of the modified nano calcium carbonate is as follows:

[0054] Step (1): Mix 10 parts of nano calcium carbonate, 180 parts of absolute ethanol and 40 parts of deionized water evenly to obtain a mixed solution, adjust the pH of the system to 9.5, heat up to 60 °C, introduce nitrogen, add 30 parts of vinyltrimethoxysilane, react for 5 h, and after filtration, washing and drying, obtain vinyl nano calcium carbonate.

[0055] Step (2): Mix 10 parts of vinyl nano calcium carbonate and 800 parts of deionized water evenly, add 15 parts of methyl methacrylate, 30 parts of methacrylamide and 10 parts of modified tea polyphenols, introduce nitrogen, add 1.3 parts of potassium persulfate, react at 75 °C for 11 h, and after centrifugation, washing and drying, obtain an amino compound-containing product.

[0056] Step (3): Mix 10 parts of the amino compound-containing product and 800 parts of 25 wt% glutaraldehyde aqueous solution evenly, stir at 30 °C for 13 h, and after centrifugation, washing and drying, obtain an aldehyde group-containing compound; mix 20 parts of chitosan and 800 parts of 1 wt% acetic acid solution evenly to obtain a chitosan solution, add 10 parts of the aldehyde group-containing compound and 3 parts of sodium borohydride, react at 30 °C for 5 h, and after centrifugation, washing and drying, obtain an intermediate.

[0057] Step (4): Mix 10 parts of the intermediate and 200 parts of isopropanol evenly, add 40 wt% sodium hydroxide solution to adjust the pH to 9.5, add 40 parts of 2,3-epoxypropyltrimethylammonium chloride, react at 65 °C for 6 h, and after precipitation, filtration, washing and drying, obtain the modified nano calcium carbonate.

[0058] The preparation method of modified tea polyphenols is as follows:

[0059] Mix 10 parts of tea polyphenols and 450 parts of ethyl acetate evenly, add 8 parts of maleic anhydride and 4 parts of pyridine, react in a water bath shaker at 60 °C for 6 h, and obtain modified tea polyphenols after rotary evaporation under reduced pressure, recrystallization, and freeze-drying.

[0060] Example 3: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0061] Step S1: Stir 80 parts of polypropylene, 8 parts of polyoxymethylene, 15 parts of modified nano calcium carbonate, 5 parts of kaolin, 4 parts of talc powder, 0.4 part of nucleating agent, 1.5 parts of lubricant, 3 parts of antioxidant, and 1.0 part of stabilizer evenly to obtain a mixture.

[0062] Step S2: Add the mixture into a twin-screw extruder for melt extrusion (the temperatures of each zone of the twin-screw extruder are: zone 1 182 °C, zone 2 192 °C, zone 3 202 °C, zone 4 212 °C, zone 5 225 °C, head 220 °C; screw speed 180 r / min), pelletize, and use an injection molding machine for injection molding. The length-diameter ratio of the screw of the injection molding machine is 15, the screw speed is 80 rpm, the temperature of the feeding section of the injection molding machine is 250 °C, the temperature of the conveying section is 260 °C, the temperature of the injection section is 280 °C, the temperature of the nozzle is 270 °C, the mold temperature is 80 °C, the injection pressure is 100 Mpa, the back pressure is 2 Mp, and after cooling and solidifying, open the mold to obtain a plastic cup.

[0063] The preparation method of modified nano calcium carbonate is as follows:

[0064] Step (1): Mix 15 parts of nano calcium carbonate, 300 parts of absolute ethanol, and 75 parts of deionized water evenly to obtain a mixed solution, adjust the pH of the system to 10, heat up to 70 °C, introduce nitrogen, add 60 parts of vinyltrimethoxysilane, react for 6 h, and obtain vinyl nano calcium carbonate after filtration, washing, and drying.

[0065] Step (2): Mix 15 parts of vinyl nano calcium carbonate and 1500 parts of deionized water evenly, add 30 parts of methyl methacrylate, 60 parts of methacrylamide, and 22.5 parts of modified tea polyphenols, introduce nitrogen, add potassium persulfate, react at 80 °C for 12 h, and obtain an amino-containing compound after centrifugation, washing, and drying.

[0066] Step (3): Mix 15 parts of amino compound and 1500 parts of 25 wt% glutaraldehyde aqueous solution evenly, stir at 35 °C for 14 h, and after centrifugation, washing, and drying, an aldehyde group-containing compound is obtained; mix 25 parts of chitosan and 1250 parts of 1 wt% acetic acid solution evenly to obtain a chitosan solution, add 15 parts of aldehyde group-containing compound and 5 parts of sodium borohydride, react at 40 °C for 6 h, and after centrifugation, washing, and drying, an intermediate is obtained.

[0067] Step (4): Mix 15 parts of the intermediate and 450 parts of isopropanol evenly, add 40 wt% sodium hydroxide solution to adjust the pH to 10, add 75 parts of 2,3-epoxypropyltrimethylammonium chloride, react at 70 °C for 7 h, and after precipitation, filtration, washing, and drying, modified nano calcium carbonate is obtained.

[0068] The preparation method of modified tea polyphenols is as follows:

[0069] Mix 25 parts of tea polyphenols and 1250 parts of ethyl acetate evenly, add 25 parts of maleic anhydride and 12.5 parts of pyridine, react in a water bath shaker at 70 °C for 7 h, and after rotary evaporation under reduced pressure, recrystallization, and freeze-drying, modified tea polyphenols are obtained.

[0070] Comparative Example 1: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0071] Compared with Example 2, in Comparative Example 1, the modified tea polyphenols are replaced with the same mass of tea polyphenols, and other steps are the same as those in Example 2.

[0072] Comparative Example 2: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0073] Compared with Example 2, in Comparative Example 2, the modified nano calcium carbonate is replaced with the same mass of nano calcium carbonate, and other steps are the same as those in Example 2.

[0074] Comparative Example 3: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0075] Compared with Example 2, in Comparative Example 3, paraformaldehyde is not added, and other steps are the same as those in Example 2.

[0076] Comparative Example 4: A preparation method of a transparent polypropylene medical plastic cup, including the following processes:

[0077] The preparation method of modified nano calcium carbonate is as follows:

[0078] Step (1): Mix 10 parts of nano calcium carbonate, 180 parts of absolute ethanol and 40 parts of deionized water evenly to obtain a mixed solution. Adjust the pH of the system to 9.5, heat up to 60 °C, introduce nitrogen, add 30 parts of vinyltrimethoxysilane, react for 5 h, and after filtration, washing and drying, vinyl nano calcium carbonate is obtained;

[0079] Step (2): Mix 10 parts of vinyl nano calcium carbonate and 800 parts of deionized water evenly, add 15 parts of methyl methacrylate, 30 parts of methacrylamide and 10 parts of modified tea polyphenols, introduce nitrogen, add 1.3 parts of potassium persulfate, and react at 75 °C for 11 h. After centrifugation, washing and drying, an amino group-containing compound is obtained;

[0080] Step (3): Mix 10 parts of the amino group-containing compound and 800 parts of 25 wt% glutaraldehyde aqueous solution evenly, stir at 30 °C for 13 h, and after centrifugation, washing and drying, an aldehyde group-containing compound is obtained; Mix 20 parts of chitosan and 800 parts of 1 wt% acetic acid solution evenly to obtain a chitosan solution, add 10 parts of the aldehyde group-containing compound and 3 parts of sodium borohydride, react at 30 °C for 5 h, and after centrifugation, washing and drying, an intermediate is obtained;

[0081] Step (4): Mix 10 parts of the intermediate and 200 parts of isopropanol evenly, add 40 wt% sodium hydroxide solution to adjust the pH to 9.5, add 10 parts of 2,3-epoxypropyltrimethylammonium chloride, react at 65 °C for 6 h, and after precipitation, filtration, washing and drying, modified nano calcium carbonate is obtained;

[0082] Compared with Example 2, in Step (4) of Comparative Example 4, the mass ratio of the intermediate to 2,3-epoxypropyltrimethylammonium chloride is 1:1, and other steps are the same as those in Example 2.

[0083] Experiment: Take the plastic cups obtained in Examples 1-3 and Comparative Examples 1-4 to prepare specimens, and detect their properties respectively and record the detection results:

[0084] Tensile property test: Conduct according to GB / T1040.2-2022, with a tensile rate of 50 mm / min.

[0085] Xenon lamp aging test: According to GB / T 16422.2-2014, using a xenon lamp as the light source, with an irradiation intensity of 0.51 W / m 2 , the black standard temperature cycles between 65 °C and 100 °C, the exposure period is 102 min of drying and 18 min of spraying, the test time is 96 h, measure the tensile strength before and after aging, and calculate the tensile strength retention rate.

[0086] Antibacterial test: The antibacterial performance was tested by the plate colony counting method. The test strain was Staphylococcus aureus (ATCC6538). Under sterile conditions, the strain was inoculated into sterilized nutrient broth and cultured at 37°C for 24 h to obtain a concentrated bacterial solution. The concentrated bacterial solution was inoculated onto a nutrient agar plate with an inoculation loop and cultured at 37°C for 24 h. A single well-grown colony was picked and inoculated into a nutrient broth medium and cultured under the same conditions for 48 h. The bacterial solution concentration was adjusted to 1×10 9 CFU / L for standby. The plastic cup was made into a specimen with a size of 50 mm × 50 mm, disinfected with 75% ethanol and dried. 0.2 mL of the bacterial solution was dropped on the surface of the specimen, and a polyethylene film with a thickness of 0.10 mm was covered on the surface of the specimen. It was cultured in a constant temperature incubator for 24 h at a temperature of 37°C and a relative humidity of 90%. After 24 h, the bacterial solution was eluted with an eluent, and the eluent was counted by the plate counting method. Three parallel samples were tested for each group of samples, and the results were averaged.

[0087] The test results are as follows:

[0088]

[0089] Based on the data in the above table, the following conclusions can be clearly obtained:

[0090] Compared with Examples 1-3, the tensile strength retention rate of the product obtained in Comparative Example 1 decreased, indicating that by modifying tea polyphenols, the reaction activity was improved, enabling it to effectively coat nano-calcium carbonate, thereby enhancing its anti-aging performance.

[0091] Compared with Examples 1-3, both the tensile strength and the tensile strength retention rate of the product obtained in Comparative Example 2 decreased, indicating that the modified nano-calcium carbonate prepared by the present invention has better compatibility, antioxidant property and antibacterial property compared with unmodified nano-calcium carbonate; the tensile strength of the product obtained in Comparative Example 3 decreased, indicating that adding polyoxymethylene is beneficial to improving the mechanical properties of the material.

[0092] Compared with Examples 1-3, the antibacterial rate of the product obtained in Comparative Example 4 decreased, indicating that when the addition amount of 2,3-epoxypropyltrimethylammonium chloride was reduced, the antibacterial property of the material decreased.

[0093] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, 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 included in the present invention.

Claims

1. A method for preparing a transparent polypropylene medical plastic cup, characterized in that: The steps include: Step S1: mixing polypropylene, polyoxymethylene, modified nano calcium carbonate, kaolin, talcum powder, a nucleating agent, a lubricant, an antioxidant and a stabilizer to obtain a mixture; Step S2: adding the mixed material into a twin-screw extruder for melt extrusion, granulation, and injection molding to obtain a plastic cup; The preparation method of the modified nano calcium carbonate is as follows: Step (1): uniformly mix nano calcium carbonate, anhydrous ethanol and deionized water to obtain a mixed solution, adjust the pH value of the system to 9-10, heat to 50-70° C., introduce nitrogen, add vinyl trimethoxysilane, react for 4-6 hours, filter, wash and dry to obtain vinyl nano calcium carbonate; Step (2): uniformly mixing vinyl nano-calcium carbonate and deionized water, adding methyl methacrylate, methacrylamide and modified tea polyphenols, introducing nitrogen, adding potassium persulfate, reacting at 70-80° C. for 10-12 hours, and obtaining an amino compound after centrifugation, washing and drying; Step (3): uniformly mixing the amino compound and the glutaraldehyde aqueous solution, stirring at 25-35° C. for 12-14 hours, centrifuging, washing, and drying to obtain an aldehyde-containing compound; uniformly mixing chitosan and acetic acid solution to obtain a chitosan solution, adding the aldehyde-containing compound and sodium borohydride, reacting at 20-40° C. for 4-6 hours, centrifuging, washing, and drying to obtain an intermediate; Step (4): the intermediate and isopropanol are mixed evenly, sodium hydroxide solution is added to adjust the pH to 9-10, 2,3-epoxypropyltrimethylammonium chloride is added, and the mixture is reacted at 60-70°C for 5-7h, and after precipitation, filtration, washing and drying, modified nano-calcium carbonate is obtained; In the step (4), the mass ratio of the intermediate, isopropanol and 2,3-epoxypropyltrimethylammonium chloride is 1:(15-30):(3-5); The preparation method of the modified tea polyphenols is as follows: The tea polyphenols and ethyl acetate are mixed evenly, maleic anhydride and pyridine are added, and the mixture is reacted in a water bath shaker at 50-70° C. for 5-7 hours. After vacuum rotary evaporation, recrystallization and freeze drying, the modified tea polyphenols are obtained.

2. The method for preparing a transparent polypropylene medical plastic cup according to claim 1, characterized in that: The plastic cup comprises the following components by weight: 60-80 parts of polypropylene, 3-8 parts of polyoxymethylene, 5-15 parts of modified nano calcium carbonate, 3-5 parts of kaolin, 2-4 parts of talcum powder, 0.2-0.4 parts of nucleating agent, 0.5-1.5 parts of lubricant, 1-3 parts of antioxidant and 0.5-1.0 parts of stabilizer.

3. The method for preparing a transparent polypropylene medical plastic cup according to claim 1, characterized in that: In the step (1), the mass ratio of nano-calcium carbonate, anhydrous ethanol, deionized water and vinyltrimethoxysilane is 1:(15-20):(3-5):(2-4).

4. The method for preparing a transparent polypropylene medical plastic cup according to claim 1, characterized in that: In the step (2), the mass ratio of vinyl nano-calcium carbonate, methyl methacrylate, methacrylamide and modified tea polyphenols is 1: (1-2): (2-4): (0.5-1.5).

5. The method for preparing a transparent polypropylene medical plastic cup according to claim 1, characterized in that: In the step (3), the mass ratio of the amino compound to the glutaraldehyde aqueous solution is 1:(50-100), and the concentration of the glutaraldehyde aqueous solution is 25wt%.

6. The method for preparing a transparent polypropylene medical plastic cup according to claim 2, characterized in that: The lubricant is polyethylene wax.

7. A transparent polypropylene medical plastic cup obtained according to the preparation method according to any one of claims 1 to 6.

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