Antibacterial plastic and method for producing the same

Abstract

The application provides an antibacterial polypropylene plastic, which aims to obtain a composite antibacterial agent with advantages of inorganic antibacterial agents and organic antibacterial agents by compounding the inorganic antibacterial agent and the organic antibacterial agent, and add the obtained composite antibacterial agent into the polypropylene plastic to obtain the antibacterial polypropylene plastic with good antibacterial performance, good migration resistance and long-term antibacterial property.

Description

Technical Field

[0001] This invention relates to an antibacterial plastic, and more particularly to an antibacterial polypropylene plastic. Background Technology

[0002] With the continuous development of the economy and society, plastic products are increasingly permeating people's lives. Plastics are materials with polymers as their main component, processed into specific shapes under certain conditions and able to maintain their shape at room temperature. There are many types of plastics, commonly including polyethylene, polypropylene, polyvinyl chloride, and polystyrene. By adding fillers, plasticizers, colorants, and other additives to the matrix, they can be endowed with properties such as lightweight, high strength, corrosion resistance, heat resistance, impact resistance, and tensile strength.

[0003] Polypropylene (PP), as a general-purpose plastic, has excellent mechanical properties and low cost, and is widely used in automotive parts, home appliances, toys, kitchen appliances, medical and other fields. These products often come into contact with human skin, and a large number of bacteria often adhere to the surface of the products. These harmful bacteria can continuously spread and threaten the health of people who come into contact with them. Adding antibacterial agents to plastics is an effective measure to improve the antibacterial properties of plastics.

[0004] There are many types of antibacterial agents, including inorganic, organic, and natural antibacterial agents. Inorganic antibacterial agents include silver ions, copper ions, zinc ions, zinc oxide, and titanium dioxide. Inorganic antibacterial agents have high safety, heat resistance, and durability, and are widely used in fiber, plastic, and building materials. Their disadvantages include higher price, delayed antibacterial effect (not as rapid as organic antibacterial agents in killing bacteria), and almost no inhibitory effect on fungi and molds. Organic antibacterial agents mainly consist of quaternary ammonium salts, biguanides, alcohols, chlorinated hydrochloric acid, organohalides, organometallic compounds, phenols, pyridines, imidazoles, and iodides. The advantages of organic antibacterial agents are rapid sterilization, high efficiency, and low price. However, they generally have poor heat resistance and are prone to drug resistance. Natural antibacterial agents are derived from plant and animal extracts and belong to the category of organic antibacterial agents. They are natural, environmentally friendly, non-toxic, harmless, and biocompatible. Natural antibacterial agents include chitosan, chitin, artemisia, aloe vera, etc.

[0005] Currently, research on the antibacterial properties of polypropylene mainly focuses on the single use or physical mixing of antibacterial agents. For example, Lou Xiaoan et al. prepared antibacterial materials by combining silver-based, zinc-based, and organic polymeric antibacterial agents with polypropylene (PP) using a twin-screw extruder. They studied the effects of different types of antibacterial agents on the properties of PP and evaluated the antibacterial activity, high-temperature anti-yellowing effect, and timeliness of the antibacterial materials. The results showed that silver-based, zinc-based, and organic polymeric antibacterial agents had little effect on the mechanical properties of the materials. In terms of antibacterial efficiency, organic antibacterial agents were superior to silver-based and zinc-based antibacterial agents, but organic antibacterial agents were significantly worse than silver-based and zinc-based antibacterial agents in terms of high-temperature anti-yellowing. Li Jie et al. developed antibacterial polypropylene using isothiazolinone antibacterial agents. They studied the effects of granulation temperature, injection temperature, ultraviolet aging, and color change inhibitors on the yellow index and color difference of antibacterial polypropylene, and analyzed the thermal stability of isothiazolinones using a thermogravimetric / infrared simultaneous thermal analyzer. The results showed that when the content of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one in the color-resistant antibacterial polypropylene reached 0.25% (w), the antibacterial rate against Escherichia coli and Staphylococcus aureus was greater than 99% after the sample was boiled in water at 50 °C for 16 h.

[0006] Building upon existing research, this application combines the advantages and disadvantages of both organic and inorganic antibacterial agents through chemical modification, organically integrating them. The resulting composite antibacterial agent possesses both the heat resistance and durability of inorganic antibacterial agents, as well as the high efficiency of organic antibacterial agents. Summary of the Invention

[0007] The purpose of this invention is to obtain a composite antibacterial agent that combines the advantages of both inorganic and organic antibacterial agents by compounding inorganic and organic antibacterial agents. The obtained composite antibacterial agent is then added to polypropylene plastic to obtain an antibacterial polypropylene plastic with good antibacterial properties, good migration resistance, and long-lasting antibacterial effect.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 3-5 parts composite antibacterial agent, 1-2 parts dispersant, 2-3 parts antioxidant, and 0.1-0.3 parts initiator;

[0010] Furthermore, as a preferred embodiment of the present invention, the dispersant is selected from one or more of stearic acid, polyethylene wax, and liquid paraffin.

[0011] Furthermore, as a preferred embodiment of the present invention, the antioxidant is selected from a combination of antioxidant 1010 and antioxidant 168 in a dosage ratio of 1:1.

[0012] Furthermore, as a preferred embodiment of the present invention, the initiator is selected from one or a combination of two of benzoyl peroxide and methyl ethyl ketone peroxide.

[0013] Furthermore, the present invention also provides a preparation process for an antibacterial plastic material, the specific operation steps of which are as follows:

[0014] According to the formula, 100 parts of polypropylene resin, 3-8 parts of composite antibacterial agent, 1-2 parts of dispersant, 2-3 parts of antioxidant, and 0.1-0.3 parts of initiator are added to a high-speed mixer and mixed at 600-800 rpm for 10-30 minutes to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic.

[0015] In the preparation process, the temperature of the twin-screw extruder is controlled as follows: Zone 1: 155-165℃; Zone 2: 175-185℃; Zone 3: 185-195℃; Zone 4: 205-215℃; Zone 5: 205-215℃; Zone 6: 195-205℃.

[0016] Furthermore, as a preferred embodiment of the present invention, the composite antibacterial agent is quaternary ammonium salt chitosan modified nano-TiO2 composite particles, and its preparation process is as follows:

[0017] Step 1: Add nano-TiO2 with a median particle size D50 of 10-50 nm to 100-300 mL of 95% ethanol aqueous solution for ultrasonic dispersion. After ultrasonic dispersion, add aminosilane coupling agent and triethylamine under magnetic stirring. Stir at 70-80℃ and reflux for 7-8 h. After the reaction is completed, cool to room temperature, filter successively, wash repeatedly with toluene and ethanol, and then dry in an oven to obtain modified nano-TiO2.

[0018] Step 2: Dissolve chitosan in 100-200 mL of 2% acetic acid aqueous solution, add sodium hydroxide solution to adjust pH to 8-9, heat to 80℃, add 2,3-epoxypropyltrimethylammonium chloride isopropanol solution, stir and react for 3-5 h, add anhydrous ethanol to precipitate, filter, dry the filter cake to obtain quaternary ammonium salt chitosan.

[0019] Step 3: Prepare a 200-500 mL mixed solution of N,N-dimethylformamide and water, wherein the volume percentage of water does not exceed 50% of the total solution volume;

[0020] Step 4: Add the modified nano-TiO2 prepared in Step 1 and the quaternary ammonium salt chitosan prepared in Step 2 to the mixed solution obtained in Step 3. Add 10-30 mL of N,N-dimethylformamide solution containing maleic anhydride to the above mixed solution dropwise. Stir and reflux continuously for 4-6 h. The reaction temperature should not exceed 45℃. After the reaction is completed, centrifuge, wash and dry to obtain quaternary ammonium salt chitosan modified nano-TiO2 composite particles.

[0021] In step 1, the mass ratio of nano-TiO2, aminosilane coupling agent and triethylamine is 3-6:5-10:1;

[0022] In step 2, the mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 5-6:1-3;

[0023] In step 4, the mass ratio of modified nano-TiO2, quaternary ammonium salt chitosan, and maleic anhydride is 7-8:2-3:1.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The composite antibacterial agent prepared in this invention is based on inorganic nano-TiO2. The antibacterial mechanism of inorganic nano-TiO2 is photocatalysis. It can exert its antibacterial effect immediately in the presence of light. However, inorganic particles have the problem of compatibility with polymers. In this application, the silanol groups generated by the hydrolysis of aminosilane coupling agent are condensed with the hydroxyl groups on the surface of inorganic nano-TiO2 to introduce amino groups into the surface of inorganic nano-TiO2 and modify inorganic nano-TiO2 to improve its compatibility and reactivity. Then, maleic anhydride is used as a bridge to react with the anhydride groups of maleic anhydride on the surface of inorganic nano-TiO2 and the amino groups of chitosan quaternary ammonium salt to organically combine inorganic nano-TiO2 and chitosan quaternary ammonium salt to obtain a composite antibacterial agent with high antibacterial efficiency. It can exert the characteristics of long-lasting antibacterial effect of inorganic nano-TiO2 and the characteristics of high antibacterial efficiency of chitosan quaternary ammonium salt.

[0026] (2) The maleic anhydride used in this invention organically bonds inorganic nano-TiO2 with chitosan quaternary ammonium salt, which improves the compatibility between inorganic nano-TiO2 and polypropylene resin matrix and avoids the precipitation problem of chitosan quaternary ammonium salt. At the same time, the introduced double bond functional groups can undergo polymerization reaction with a small amount of residual double bond groups in polypropylene resin matrix under the action of initiator, thereby grafting the composite antibacterial agent onto the polypropylene molecular chain and further improving its long-lasting antibacterial properties. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0028] Preparation Example 1:

[0029] The composite antibacterial agent is a quaternary ammonium salt chitosan-modified nano-TiO2 composite particle, and its preparation process is as follows:

[0030] Step 1: 8g of nano-TiO2 with a median particle size D50 of 30nm was added to 150mL of 95% ethanol aqueous solution for ultrasonic dispersion. After ultrasonic dispersion, 12g of 3-aminopropyltrimethoxysilane and 2g of triethylamine were added under magnetic stirring. The mixture was stirred at 75℃ and refluxed for 7h. After the reaction was completed, it was cooled to room temperature, filtered sequentially, washed repeatedly with toluene and ethanol, and then dried in an oven to obtain modified nano-TiO2.

[0031] Step 2: Dissolve 5g of chitosan in 100mL of 2% acetic acid aqueous solution, add sodium hydroxide solution to adjust the pH to 8, heat to 80℃, add 4g of 2,3-epoxypropyltrimethylammonium chloride in isopropanol solution, wherein the mass fraction of 2,3-epoxypropyltrimethylammonium chloride in isopropanol solution is 50%, stir and react for 4h, add anhydrous ethanol to precipitate, filter, dry the filter cake to obtain quaternary ammonium salt chitosan;

[0032] Step 3: Prepare a 200 mL mixed solution of N,N-dimethylformamide and water, wherein the water volume percentage is 20% of the total volume of the mixed solution;

[0033] Step 4: Add 7g of the modified nano-TiO2 prepared in Step 1 and 3g of the quaternary ammonium salt chitosan prepared in Step 2 to the mixed solution obtained in Step 3. Add 20mL of N,N-dimethylformamide solution containing 1g of maleic anhydride to the above mixed solution dropwise. Stir and reflux continuously for 5h, and the reaction temperature does not exceed 45℃. After the reaction is completed, centrifuge, wash and dry to obtain quaternary ammonium salt chitosan modified nano-TiO2 composite particles.

[0034] Example 1

[0035] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 3 parts composite antibacterial agent obtained in Preparation Example 1, 1 part stearic acid, 1 part antioxidant 1010, 1 part antioxidant 168, and 0.2 parts benzoyl peroxide.

[0036] The preparation process of antibacterial plastic materials is as follows:

[0037] According to the formula, 100 parts of polypropylene resin, 3 parts of the composite antibacterial agent obtained in Preparation Example 1, 1 part of stearic acid, 1 part of antioxidant 1010, 1 part of antioxidant 168, and 0.2 parts of initiator benzoyl peroxide are mixed in a high-speed mixer for 20 minutes at a speed maintained at 800 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled as follows: Zone 1: 155℃, Zone 2: 175℃, Zone 3: 185℃, Zone 4: 205℃, Zone 5: 205℃, and Zone 6: 195℃.

[0038] Example 2

[0039] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 5 parts composite antibacterial agent obtained in Preparation Example 1, 2 parts polyethylene wax, 1 part antioxidant 1076, 1 part antioxidant 168, and 0.1 parts methyl ethyl ketone peroxide.

[0040] The preparation process of antibacterial plastic materials is as follows:

[0041] According to the specified ratio, 100 parts of polypropylene resin, 5 parts of the composite antibacterial agent obtained in Preparation Example 1, 2 parts of polyethylene wax, 2 parts of antioxidant 1076, 1 part of antioxidant 168, and 0.1 parts of initiator methyl ethyl ketone peroxide are mixed in a high-speed mixer for 15 minutes at a speed maintained at 700 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled as follows: Zone 1: 160℃, Zone 2: 180℃, Zone 3: 185℃, Zone 4: 210℃, Zone 5: 205℃, and Zone 6: 195℃.

[0042] Example 3

[0043] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 8 parts composite antibacterial agent obtained in Preparation Example 1, 2 parts liquid paraffin, 1 part antioxidant 1076, 1 part antioxidant 168, and 0.3 parts methyl ethyl ketone peroxide.

[0044] The preparation process of antibacterial plastic materials is as follows:

[0045] According to the formula, 100 parts of polypropylene resin, 8 parts of the composite antibacterial agent obtained in Preparation Example 1, 2 parts of liquid paraffin, 1 part of antioxidant 1076, 1 part of antioxidant 168, and 0.3 parts of initiator methyl ethyl ketone peroxide are mixed in a high-speed mixer for 15 minutes at a speed maintained at 800 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled as follows: Zone 1: 165℃, Zone 2: 185℃, Zone 3: 185℃, Zone 4: 210℃, Zone 5: 205℃, and Zone 6: 195℃.

[0046] Comparative Example 1

[0047] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 3 parts unmodified nano-TiO2 with a median particle size D50 of 30 nm, 1 part stearic acid, 1 part antioxidant 1010, 1 part antioxidant 168, and 0.2 parts benzoyl peroxide.

[0048] The preparation process of antibacterial plastic materials is as follows:

[0049] According to the formula, 100 parts of polypropylene resin, 3 parts of unmodified nano-TiO2 with a median particle size D50 of 30nm, 1 part of stearic acid, 1 part of antioxidant 1010, 1 part of antioxidant 168, and 0.2 parts of initiator benzoyl peroxide are mixed in a high-speed mixer for 20 minutes at a speed of 800 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled at 155℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, 205℃ in zone 4, 205℃ in zone 5, and 195℃ in zone 6.

[0050] Comparative Example 2

[0051] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 3 parts quaternary ammonium salt chitosan obtained in step 2 of Preparation Example 1, 1 part stearic acid, 1 part antioxidant 1010, 1 part antioxidant 168, and 0.2 parts benzoyl peroxide.

[0052] The preparation process of antibacterial plastic materials is as follows:

[0053] According to the formula, 100 parts of polypropylene resin, 3 parts of quaternary ammonium salt chitosan obtained in step 2 of Preparation Example 1, 1 part of stearic acid, 1 part of antioxidant 1010, 1 part of antioxidant 168, and 0.2 parts of initiator benzoyl peroxide are mixed in a high-speed mixer for 20 minutes at a speed of 800 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled as follows: zone 1: 155℃, zone 2: 175℃, zone 3: 185℃, zone 4: 205℃, zone 5: 205℃, and zone 6: 195℃.

[0054] Comparative Example 3

[0055] An antibacterial plastic, by weight, is composed of the following raw materials: 100 parts polypropylene resin, 2.1 parts unmodified nano-TiO2 with a median particle size D50 of 30 nm, 0.9 parts quaternary ammonium salt chitosan obtained in step 2 of Preparation Example 1, 1 part stearic acid, 1 part antioxidant 1010, 1 part antioxidant 168, and 0.2 parts benzoyl peroxide;

[0056] The preparation process of antibacterial plastic materials is as follows:

[0057] According to the formula, 100 parts of polypropylene resin, 2.1 parts of unmodified nano-TiO2 with a median particle size D50 of 30 nm, 0.9 parts of quaternary ammonium salt chitosan obtained in step 2 of Preparation Example 1, 1 part of stearic acid, 1 part of antioxidant 1010, 1 part of antioxidant 168, and 0.2 parts of initiator benzoyl peroxide are mixed in a high-speed mixer for 20 minutes at a speed of 800 rpm to ensure uniform dispersion of the materials. After uniform mixing, the material is discharged and cooled. The cooled mixture is then fed into a twin-screw extruder for melt extrusion to obtain strip-shaped material. The extruded strip-shaped material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic. In the preparation process, the temperature of the twin-screw extruder is controlled as follows: zone 1: 155℃, zone 2: 175℃, zone 3: 185℃, zone 4: 205℃, zone 5: 205℃, and zone 6: 195℃.

[0058] Experimental Example 1

[0059] The antibacterial plastics prepared in Examples 1-3 and Comparative Examples 1-3 were injection molded into test samples using a horizontal injection molding machine, and then relevant performance tests were conducted on each test sample.

[0060] The test methods for various properties of antibacterial plastic materials are as follows:

[0061] Tensile strength was tested according to ASTM D-638 standard;

[0062] Bending strength and flexural modulus were tested according to ASTM D-790 standard.

[0063] Notched impact performance was tested according to ASTM D-256 standard.

[0064] The specific test results are shown in Table 1 below:

[0065] Table 1. Mechanical property test results

[0066]

[0067] Experimental Example 2

[0068] The antibacterial properties of the antibacterial plastic materials prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The specific antibacterial property testing method followed GB / T 31402-2015. The antibacterial rate of each test sample was examined, and the specific test results are shown in Table 2 below.

[0069] Table 2: Inhibition rate (%) against Staphylococcus aureus and Escherichia coli

[0070]

[0071] According to the experimental results in Tables 1 and 2, the antibacterial polypropylene plastics prepared in Examples 1-3 of this application are superior to those in Comparative Examples 1-3 in terms of antibacterial properties and mechanical properties. The antibacterial polypropylene plastics prepared by this invention combine the advantages and disadvantages of organic and inorganic antibacterial agents. Through chemical modification, inorganic and organic antibacterial agents are organically combined, and the resulting composite antibacterial agent has both the durability of inorganic antibacterial agents and the high efficiency of organic antibacterial agents.

[0072] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the defined scope, they should all fall within the protection scope of the present invention.

Claims

1. An antibacterial plastic material, characterized in that, The raw materials, by weight, consist of the following components: 100 parts polypropylene resin, 3-5 parts composite antibacterial agent, 1-2 parts dispersant, 2-3 parts antioxidant, and 0.1-0.3 parts initiator. The composite antibacterial agent is a quaternary ammonium salt chitosan-modified nano-TiO2 composite particle, and its preparation process is as follows: Step 1: Add nano-TiO2 with a median particle size D50 of 10-50 nm to 100-300 mL of 95% ethanol aqueous solution for ultrasonic dispersion. After ultrasonic dispersion, add aminosilane coupling agent and triethylamine under magnetic stirring. Stir at 70-80℃ and reflux for 7-8 h. After the reaction is completed, cool to room temperature, filter successively, wash repeatedly with toluene and ethanol, and then dry in an oven to obtain modified nano-TiO2. Step 2: Dissolve chitosan in 100-200 mL of 2% acetic acid aqueous solution, add sodium hydroxide solution to adjust pH to 8-9, heat to 80℃, add 2,3-epoxypropyltrimethylammonium chloride isopropanol solution, stir and react for 3-5 h, add anhydrous ethanol to precipitate, filter, dry the filter cake to obtain quaternary ammonium salt chitosan. Step 3: Prepare a 200-500 mL mixed solution of N,N-dimethylformamide and water, wherein the volume percentage of water does not exceed 50% of the total solution volume; Step 4: Add the modified nano-TiO2 prepared in Step 1 and the quaternary ammonium salt chitosan prepared in Step 2 to the mixed solution prepared in Step 3. Add 10-30 mL of N,N-dimethylformamide solution containing maleic anhydride to the above mixed solution dropwise. Stir and reflux continuously for 4-6 h. The reaction temperature should not exceed 45℃. After the reaction is completed, centrifuge, wash and dry to obtain quaternary ammonium salt chitosan modified nano-TiO2 composite particles. In step 2, the mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 5-6:1-3; In step 4, the mass ratio of modified nano-TiO2, quaternary ammonium salt chitosan to maleic anhydride is 7-8:2-3:

1.

2. The antibacterial plastic material according to claim 1, characterized in that, The dispersant is selected from one or more of the following: stearic acid, polyethylene wax, and liquid paraffin.

3. The antibacterial plastic material according to claim 1, characterized in that, The antioxidant is selected from a combination of antioxidant 1010 and antioxidant 168 in a 1:1 ratio.

4. The antibacterial plastic material according to claim 1, characterized in that, The initiator is selected from one or a combination of two of benzoyl peroxide and methyl ethyl ketone peroxide.

5. The antibacterial plastic material according to claim 1, characterized in that, In step 1, the mass ratio of nano-TiO2, aminosilane coupling agent and triethylamine is 3-6:5-10:

1.

6. The preparation process of the antibacterial plastic material according to any one of claims 1-5, characterized in that, The preparation process of the antibacterial plastic material is as follows: 100 parts of polypropylene resin, 3-5 parts of composite antibacterial agent, 1-2 parts of dispersant, 2-3 parts of antioxidant, and 0.1-0.3 parts of initiator are added to a high-speed mixer according to the formula. The mixture is mixed at a speed of 600-800 rpm for 10-30 minutes to make the material evenly dispersed. After the mixture is evenly mixed, it is discharged and cooled. The cooled mixture is fed into a twin-screw extruder for melt extrusion to obtain strip material. The extruded strip material is cooled in a water tank, drawn into a pelletizer for granulation, and dried to obtain polypropylene antibacterial plastic.

7. The preparation process of an antibacterial plastic material according to claim 6, characterized in that, The twin-screw extruder has the following temperature zones: Zone 1: 155-165℃; Zone 2: 175-185℃; Zone 3: 185-195℃; Zone 4: 205-215℃; Zone 5: 205-215℃; and Zone 6: 195-205℃.

Images