An antibacterial polypropylene film and its preparation method

Abstract

The present invention relates to the technical field of the preparation of polypropylene films, and specifically discloses an antibacterial polypropylene film and a preparation method thereof. An antibacterial polypropylene film comprises 100 parts of polypropylene, 4 - 8 parts of a PE masterbatch, 2 - 4 parts of an antiblocking agent, 0.1 - 0.3 part of white mineral oil, and 5 - 8 parts of an antibacterial agent; the preparation method of the antibacterial agent includes first calcining vermiculite, then adding sodium hexametaphosphate, hydroxyethyl cellulose, diethylenetriamine and water, and then adding silver ion compounds, zinc ion compounds and copper ion compounds to obtain the antibacterial agent. The antibacterial polypropylene film provided in this application not only ensures the uniform dispersion of the antibacterial agent in the polypropylene matrix, but also guarantees the good antibacterial property of the polypropylene film, while maintaining the physical properties of the film.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of polypropylene films, and more particularly to an antibacterial polypropylene film and a preparation method thereof. Background Art

[0002] Polypropylene (PP) films have various advantages, such as high light transmittance, good mechanical properties, non-toxicity, heat resistance, chemical resistance, and low cost. Therefore, they have been increasingly widely used in the packaging industry. However, during use, PP films are prone to adsorbing impurities such as dust and hair, which not only affects the appearance and quality of the products, but also is extremely likely to grow bacteria, leading to the contamination of the packaged products. To overcome this problem, people have tried to add various antibacterial agents to polypropylene films in order to achieve the purpose of inhibiting bacterial growth. However, although traditional inorganic antibacterial agents have characteristics such as good heat resistance, long antibacterial persistence time, and high safety, the surface free energy of their powder is high, showing hydrophilicity and strong agglomeration tendency, while the surface free energy of PP is low, showing lipophilicity, and the compatibility between the two is poor, which will lead to uneven dispersion of the antibacterial agent in the matrix resin and affect the antibacterial effect.

[0003] Therefore, developing an antibacterial polypropylene film that can effectively inhibit bacterial growth and has good compatibility is an urgent technical problem to be solved in the current field of polypropylene films. Summary of the Invention

[0004] In order to obtain an antibacterial polypropylene film that can not only effectively inhibit bacterial growth but also has good compatibility among various raw materials, especially good compatibility between the antibacterial agent and polypropylene, the present application provides an antibacterial polypropylene film and a preparation method thereof. The antibacterial polypropylene film provided by the present application not only improves the compatibility between the antibacterial agent and polypropylene, ensures the uniform dispersion of the antibacterial agent in the polypropylene matrix, but also guarantees the good antibacterial property of the polypropylene film, while maintaining the physical properties of the film, making its application in the packaging field more extensive and safe.

[0005] In the first aspect, an antibacterial polypropylene film provided by the present application adopts the following technical solution:

[0006] An antibacterial polypropylene film, comprising the following raw materials in parts by weight: 100 parts of polypropylene, 4 - 8 parts of PE masterbatch, 2 - 4 parts of antiblocking agent, 0.1 - 0.3 parts of white mineral oil, and 5 - 8 parts of antibacterial agent;

[0007] The preparation method of the antibacterial agent comprises the following steps:

[0008] Step 1: Take vermiculite, crush it into powder with a particle size of 100 - 200 mesh, and calcine it at 600 - 900 °C for 3 - 4 h;

[0009] Step 2: Take 100 parts of calcined vermiculite, mix it with 1 - 2 parts of sodium hexametaphosphate, 1 - 2 parts of hydroxyethyl cellulose, and 0.5 - 1 part of diethylenetriamine, add 1000 parts of water, and perform ultrasonic oscillation treatment until a suspension is formed;

[0010] Step 3: Continuously stir the suspension, and add 1 - 2 parts of silver ion compound, 0.5 - 1 part of zinc ion compound, and 0.5 - 1 part of copper ion compound, and continue stirring for 2 - 3 h;

[0011] Step 4: Filter, wash, dry, and grind the mixed solution obtained in Step 3 to obtain the antibacterial agent.

[0012] In the above technical solution, in this application, by adding a specially prepared antibacterial agent to the polypropylene film, not only the compatibility between the antibacterial agent and polypropylene is improved, ensuring the uniform dispersion of the antibacterial agent in the polypropylene matrix, but also the good antibacterial property of the polypropylene film is guaranteed. By using calcined vermiculite as the matrix of the antibacterial agent, the high specific surface area of the antibacterial agent is ensured. By mixing vermiculite with sodium hexametaphosphate, hydroxyethyl cellulose, and diethylenetriamine, not only the dispersibility of the antibacterial agent is improved, the compatibility between the antibacterial agent and polypropylene is enhanced, which helps the stable existence of the antibacterial agent in the polypropylene matrix, but also helps the uniform adsorption and binding of vermiculite to silver, zinc, and copper ions, thereby forming uniformly distributed antibacterial active centers in the antibacterial agent. By combining vermiculite with silver, zinc, and copper ion compounds, using the layered structure and ion exchange properties of vermiculite, the antibacterial agent is uniformly dispersed in the polypropylene film, thus significantly improving the antibacterial effect.

[0013] In addition, the antibacterial agent prepared in this application can play a role in heterogeneous nucleation during the crystallization process of polypropylene, promoting the crystallization of polypropylene, improving the crystallization rate and crystallinity of polypropylene, and thus further improving the mechanical properties of the polypropylene film.

[0014] Preferably, the silver ion compound is silver nitrate, the zinc ion compound is zinc nitrate, and the copper ion compound is copper nitrate.

[0015] In the above technical solution, in this application, by selecting silver nitrate, zinc nitrate, and copper nitrate as the ion sources, they can provide stable ion release in the antibacterial agent, thus ensuring the long - term effectiveness and high efficiency of the antibacterial agent. Silver ions have a broad - spectrum antibacterial effect and can effectively inhibit the growth of various bacteria and fungi; zinc ions help to enhance the stability and safety of the antibacterial agent; copper ions can further enhance the antibacterial effect. The three work together, making the antibacterial polypropylene film perform excellently in inhibiting bacterial growth.

[0016] Preferably, in Step 4, it is ground to a particle size of 0.1 - 0.5 μm.

[0017] In the above technical solution, the present application controls the particle size of the antibacterial agent within the range of 0.1 - 0.5 μm, further enhancing its dispersibility in the polypropylene matrix and ensuring the balance between the antibacterial performance and physical properties of the film.

[0018] Preferably, the releasing agent is a mixture of erucamide and stearamide in a mass ratio of 1:(1 - 2).

[0019] In the above technical solution, by selecting erucamide and stearamide as the releasing agent, the present application effectively improves the releasing performance of the film and reduces the adhesion problem of the film during use.

[0020] Preferably, it includes the following raw materials in parts by weight: 100 parts of polypropylene, 5 parts of PE masterbatch, 3 parts of releasing agent, 0.1 part of white mineral oil, and 6 parts of antibacterial agent.

[0021] In the above technical solution, by further optimizing the dosage of each raw material of the antibacterial polypropylene film, the present application ensures that while the film has excellent antibacterial performance, it also has good physical and mechanical properties and processing properties. The antibacterial polypropylene film of the present application can not only effectively inhibit the growth of bacteria, but also has good mechanical properties.

[0022] In the second aspect, a preparation method of an antibacterial polypropylene film provided by the present application adopts the following technical solution:

[0023] A preparation method of an antibacterial polypropylene film includes the following steps:

[0024] Step 1: Mix the raw materials, melt and extrude them into pellets in a single-screw extruder to obtain an antibacterial polypropylene masterbatch;

[0025] Step 2: Place the antibacterial polypropylene masterbatch in a blow molding machine, and prepare an antibacterial polypropylene film through the processes of downward blowing, film coating, and winding.

[0026] In the above technical solution, through the above preparation method, the antibacterial polypropylene film provided by the present application not only has excellent antibacterial performance, but also shows good performance in terms of physical and mechanical properties and processing properties, and is particularly suitable for the packaging industry with high hygiene requirements.

[0027] Preferably, the barrel temperature of the blow molding machine in Step 2 is 170 - 190 °C.

[0028] In the above technical solution, by controlling the barrel temperature of the blow molding machine within the range of 170 - 190 °C, the present application ensures the uniform melting and good molding performance of the antibacterial polypropylene masterbatch during the blow molding process, and further optimizes the mechanical properties of the film, making it more stable and reliable in practical applications.

[0029] Preferably, step 1 includes:

[0030] Step 1-1: Mix an antibacterial agent with polypropylene accounting for 8%-10% by weight of the formulation, melt and extrude granulate in a single-screw extruder to obtain an antibacterial masterbatch;

[0031] Step 1-2: Mix the antibacterial masterbatch obtained in step 1-1 with the remaining raw materials, melt and extrude granulate in a single-screw extruder to obtain an antibacterial polypropylene masterbatch.

[0032] In the above technical solution, in the present application, by pre-mixing the antibacterial agent with polypropylene to obtain an antibacterial masterbatch and then further mixing to obtain an antibacterial polypropylene masterbatch, the uniform distribution of the antibacterial agent in the polypropylene matrix can be further improved, and the antibacterial agent can be better dispersed in the masterbatch. This pre-mixing method can further improve the compatibility between the antibacterial agent and polypropylene, further reduce the agglomeration phenomenon of the antibacterial agent, thereby ensuring the uniformity and stability of the antibacterial polypropylene film.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. In the present application, through the calcination treatment of vermiculite, through the optimization of the dispersion performance of vermiculite using sodium hexametaphosphate, hydroxyethyl cellulose, and diethylenetriamine, and through the uniform adsorption and combination of silver, zinc, copper ions and vermiculite, the antibacterial agent can be evenly dispersed in the polypropylene film, thereby significantly improving the antibacterial effect.

[0035] 2. The antibacterial agent prepared in the present application can also well improve the mechanical properties of the polypropylene film, play a role in heterogeneous nucleation during the crystallization process of polypropylene, promote the crystallization of polypropylene, and improve the crystallization rate and crystallinity of polypropylene.

[0036] 3. In the present application, by selecting erucamide and stearamide as the anti-blocking agents, the anti-blocking performance of the film can be effectively improved, the film-forming property and service performance of the film can be improved, and the adhesion problem of the film during use can be reduced.

[0037] 4. In the present application, by optimizing the preparation steps of the antibacterial polypropylene film, by pre-mixing the antibacterial agent with polypropylene to obtain an antibacterial masterbatch and then mixing to obtain an antibacterial polypropylene masterbatch, the uniform distribution of the antibacterial agent in the polypropylene matrix is further improved, and the antibacterial agent can be better dispersed in the masterbatch. Detailed Embodiments

[0038] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Preparation Example 1

[0040] A preparation method of an antibacterial agent, comprising the following steps:

[0041] Step 1: Take vermiculite, crush it into powder with a particle size of 100 mesh, and calcine it at 600 °C for 4 h.

[0042] Step 2: Take 1000 g of the calcined vermiculite, mix it with 10 g of sodium hexametaphosphate, 20 g of hydroxyethyl cellulose, and 10 g of diethylenetriamine, add 10000 g of water, and perform ultrasonic oscillation treatment for 30 min to form a suspension.

[0043] Step 3: Continuously stir the suspension, and add 10 g of silver nitrate, 10 g of zinc nitrate, and 10 g of copper nitrate, and continue stirring for 3 h.

[0044] Step 4: Filter, wash, dry at 120 °C, and grind the mixed solution obtained in Step 3 to a particle size between 0.1 - 0.5 μm to obtain the antibacterial agent.

[0045] Preparation Example 2

[0046] A preparation method of an antibacterial agent, which is different from Preparation Example 1 and includes the following steps:

[0047] Step 1: Take vermiculite, crush it into powder with a particle size of 100 - 200 mesh, and calcine it at 600 - 900 °C for 3 - 4 h.

[0048] Step 2: Take 1000 g of the calcined vermiculite, mix it with 20 g of sodium hexametaphosphate, 10 g of hydroxyethyl cellulose, and 5 g of diethylenetriamine, add 10000 g of water, and perform ultrasonic oscillation treatment for 40 min to form a suspension.

[0049] Step 3: Continuously stir the suspension, and add 20 g of silver nitrate, 5 g of zinc nitrate, and 5 g of copper nitrate, and continue stirring for 2 h.

[0050] Step 4: Filter, wash, dry at 120 °C, and grind the mixed solution obtained in Step 3 to a particle size between 0.1 - 0.5 μm to obtain the antibacterial agent.

[0051] Preparation Example 3

[0052] A preparation method of an antibacterial agent, which is different from Preparation Example 1 and includes the following steps:

[0053] Step 1: Take vermiculite, crush it into powder with a particle size of 150 mesh, and calcine it at 800 °C for 4 h.

[0054] Step 2: Take 1000 g of the calcined vermiculite, mix it with 15 g of sodium hexametaphosphate, 15 g of hydroxyethyl cellulose, and 8 g of diethylenetriamine, add 10000 g of water, and perform ultrasonic oscillation treatment for 40 min to form a suspension.

[0055] Step 3: Continuously stir the suspension, add 15 g of silver nitrate, 8 g of zinc nitrate, and 8 g of copper nitrate, and continue stirring for 3 h.

[0056] Step 4: Filter, wash, dry at 120 °C, and grind the mixed solution obtained in Step 3 to a particle size between 0.1 - 0.5 μm to obtain the antibacterial agent.

[0057] Comparative Preparation Example 1

[0058] A preparation method of an antibacterial agent, different from Preparation Example 1, is that the sodium hexametaphosphate in Step 2 is replaced with sodium polyphosphate in equal amount.

[0059] Comparative Preparation Example 2

[0060] A preparation method of an antibacterial agent, different from Preparation Example 1, is that the hydroxyethyl cellulose in Step 2 is replaced with polyvinyl alcohol in equal amount.

[0061] Comparative Preparation Example 3

[0062] A preparation method of an antibacterial agent, different from Preparation Example 1, is that the diethylenetriamine in Step 2 is replaced with sodium dodecyl sulfate in equal amount.

[0063] Example 1

[0064] An antibacterial polypropylene film comprises 1000 g of polypropylene, 40 g of PE masterbatch, 20 g of opening agent, 1 g of white mineral oil, and 50 g of antibacterial agent.

[0065] Among them, the polypropylene is purchased from Tomorrow Holdings Co., Ltd.

[0066] Among them, the PE masterbatch is purchased from Dongguan Jin Cai New Materials Co., Ltd.

[0067] Among them, the white mineral oil is purchased from Shaoguan Runbo Trading Co., Ltd.

[0068] Among them, the antibacterial agent is from Preparation Example 1.

[0069] Among them, the opening agent is erucamide.

[0070] Among them, the preparation method of the antibacterial polypropylene film includes the following steps:

[0071] Step 1, prepare antibacterial polypropylene particles:

[0072] Step 1-1: Mix the antibacterial agent and 8% by weight of the polypropylene in the formula and add them into a single-screw extruder, melt and extrude into pellets at 170 °C to obtain the antibacterial masterbatch.

[0073] Step 1-2: Mix the antibacterial masterbatch obtained in Step 1-1 with the remaining raw materials, melt and extrude into pellets in a single-screw extruder at 170 °C to obtain the antibacterial polypropylene masterbatch.

[0074] Step 2: Place the antibacterial polypropylene masterbatch in a blow molding machine, adjust the barrel temperature to 170 °C, and prepare an antibacterial polypropylene film through the processes of downward blowing, film coating, and winding.

[0075] Example 2

[0076] An antibacterial polypropylene film, different from Example 1, includes 1000 g of polypropylene, 80 g of PE masterbatch, 40 g of an antiblocking agent, 3 g of white mineral oil, and 80 g of an antibacterial agent.

[0077] Among them, the antibacterial agent is from Preparation Example 2.

[0078] Among them, the antiblocking agent is a mixture of erucamide and stearamide in a mass ratio of 1:2.

[0079] Among them, the preparation method of the antibacterial polypropylene film includes the following steps:

[0080] Step 1, prepare antibacterial polypropylene pellets:

[0081] Step 1-1: Mix the antibacterial agent and 10% by weight of polypropylene in the formulation and add them to a single-screw extruder, melt and extrude into pellets at 190 °C to obtain an antibacterial masterbatch.

[0082] Step 1-2: Mix the antibacterial masterbatch obtained in Step 1-1 with the remaining raw materials, melt and extrude into pellets in a single-screw extruder at 190 °C to obtain an antibacterial polypropylene masterbatch.

[0083] Step 2: Place the antibacterial polypropylene masterbatch in a blow molding machine, adjust the barrel temperature to 190 °C, and prepare an antibacterial polypropylene film through the processes of downward blowing, film coating, and winding.

[0084] Example 3

[0085] An antibacterial polypropylene film, different from Example 1, includes 1000 g of polypropylene, 50 g of PE masterbatch, 30 g of an antiblocking agent, 1 g of white mineral oil, and 60 g of an antibacterial agent.

[0086] Among them, the antibacterial agent is from Preparation Example 3.

[0087] Among them, the antiblocking agent is a mixture of erucamide and stearamide in a mass ratio of 1:1.

[0088] Among them, the preparation method of the antibacterial polypropylene film includes the following steps:

[0089] Step 1, prepare antibacterial polypropylene pellets:

[0090] Step 1-1: Mix the antibacterial agent and 9% by weight of polypropylene in the formulation and add them into a single-screw extruder. Melt and extrude into pellets at 180 °C to obtain the antibacterial masterbatch.

[0091] Step 1-2: Mix the antibacterial masterbatch obtained in Step 1-1 with the remaining raw materials, melt and extrude into pellets at 180 °C in a single-screw extruder to obtain the antibacterial polypropylene masterbatch.

[0092] Step 2: Place the antibacterial polypropylene masterbatch in a blow molding machine, adjust the barrel temperature to 180 °C, and produce the antibacterial polypropylene film through the processes of downward blowing, film coating, and winding.

[0093] Example 4

[0094] An antibacterial polypropylene film, different from Example 1 in that the preparation method of the antibacterial polypropylene film includes the following steps: Step 1: Mix the raw materials and add them into a single-screw extruder, melt and extrude into pellets at 180 °C to obtain the antibacterial polypropylene masterbatch.

[0095] Step 2: Place the antibacterial polypropylene masterbatch in a blow molding machine, adjust the barrel temperature to 180 °C, and produce an antibacterial polypropylene film with a thickness of 50 μm through the processes of downward blowing, film coating, and winding.

[0096] Comparative Example 1

[0097] An antibacterial polypropylene film, different from Example 1 in that the antibacterial agent is from Comparative Preparation Example 1.

[0098] Comparative Example 2

[0099] An antibacterial polypropylene film, different from Example 1 in that the antibacterial agent is from Comparative Preparation Example 2.

[0100] Comparative Example 3

[0101] An antibacterial polypropylene film, different from Example 1 in that the antibacterial agent is from Comparative Preparation Example 3.

[0102] Control Example

[0103] A polypropylene film, different from Example 1 in that no antibacterial agent is added.

[0104] Performance Testing

[0105] Test 1, Antibacterial Property Test:

[0106] Test Samples: The antibacterial polypropylene films of the above examples, comparative examples, and control example, size: 40 mm * 40 mm, thickness 50 μm.

[0107] Detection method: Carry out in accordance with the film pasting method in Appendix C of GB / T 21510-2008. After the sample is in contact with the bacterial solution for 18 h, elute the sample in 20 mL of sterile water. After shaking well, dilute the eluent by 10 times, take 1 mL and inoculate it in a petri dish. After culturing at 37 °C for 24 h, take it out for viable bacteria culture counting. The determination of the total number of colonies (CFU) is carried out in accordance with GB / T 4789.2-2008.

[0108] Test strains: Escherichia coli ATCC25992, Staphylococcus aureus ATCC25923.

[0109] Calculation of test results: Antibacterial rate (%) = [(CFU of blank control - CFU of sample) / CFU of blank control] × 100%.

[0110] According to the standard, when the antibacterial rate reaches or exceeds 90% after the antibacterial film is in contact with the bacterial solution for 18 h, it can be indicated that the material has antibacterial effect; if the antibacterial rate reaches more than 99%, it indicates that the material has strong antibacterial effect.

[0111] The test results are shown in Table 1.

[0112] Test 2, Mechanical property test:

[0113] Test samples: The antibacterial polypropylene films of the above-mentioned examples, comparative examples and control examples, size: 100 mm × 15 mm, thickness 100 μm.

[0114] Test method: Refer to GB / T 13022.91 "Test Method for Tensile Properties of Plastic Films" to test the maximum load and elongation at break of the sample. The tensile speed is 50 mm / min and the test gauge length is 50 mm.

[0115] The test results are shown in Table 1.

[0116] Table 1:

[0117]

[0118]

[0119] Specifically, in combination with the experimental data analysis in Table 1, it can be seen that the antibacterial polypropylene films of Examples 1-4 have an antibacterial rate of over 90% against Escherichia coli and Staphylococcus aureus, indicating that the antibacterial polypropylene films of Examples 1-4 have strong antibacterial effects. In terms of mechanical properties, the maximum load and elongation at break of the antibacterial polypropylene films of Examples 1-4 are both maintained at a good level, indicating that the polypropylene film added with antibacterial agents can not only maintain the antibacterial performance but also maintain and improve the mechanical properties well. Thus, it can be seen that by mixing the calcined vermiculite with sodium hexametaphosphate, hydroxyethyl cellulose and diethylenetriamine, the present application can not only optimize the dispersion performance of the antibacterial agent, improve the binding rate of silver, zinc, copper ions and vermiculite, thereby significantly improving the antibacterial effect, but also well improve the mechanical properties of the polypropylene film.

[0120] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment as needed after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An antibacterial polypropylene film, characterized in that, It comprises the following raw materials in parts by weight: 100 parts of polypropylene, 4 - 8 parts of PE masterbatch, 2 - 4 parts of antiblocking agent, 0.1 - 0.3 part of white mineral oil, 5 - 8 parts of antibacterial agent; The preparation method of the antibacterial agent comprises the following steps: Step 1: Take vermiculite, crush it into powder with a particle size of 100 - 200 mesh, and calcine it at 600 - 900 °C for 3 - 4 h; Step 2: Take 100 parts of the calcined vermiculite, mix it with 1 - 2 parts of sodium hexametaphosphate, 1 - 2 parts of hydroxyethyl cellulose, and 0.5 - 1 part of diethylenetriamine, add 1000 parts of water, and perform ultrasonic oscillation treatment until a suspension is formed; Step 3: Continuously stir the suspension, and add 1 - 2 parts of silver ion compound, 0.5 - 1 part of zinc ion compound, and 0.5 - 1 part of copper ion compound, and continue stirring for 2 - 3 h; Step 4: Filter, wash, dry, and grind the mixed solution obtained in Step 3 to obtain the antibacterial agent.

2. The antibacterial polypropylene film according to claim 1, characterized in that The silver ion compound is silver nitrate, the zinc ion compound is zinc nitrate, and the copper ion compound is copper nitrate.

3. An antibacterial polypropylene film according to claim 1, characterized in that, In Step 4, it is ground to a particle size of 0.1 - 0.5 μm.

4. The antibacterial polypropylene film according to claim 1, characterized in that, The antiblocking agent is composed of erucamide and stearamide mixed in a mass ratio of 1:(1 - 2).

5. An antibacterial polypropylene film according to claim 1, characterized in that, It comprises the following raw materials in parts by weight: 100 parts of polypropylene, 5 parts of PE masterbatch, 3 parts of antiblocking agent, 0.1 part of white mineral oil, 6 parts of antibacterial agent.

6. A method for preparing an antibacterial polypropylene film according to any one of claims 1-5, characterized in that, It comprises the following steps: Step 1: Mix the raw materials, melt and extrude them into pellets in a single - screw extruder to obtain antibacterial polypropylene masterbatch; Step 2: Place the antibacterial polypropylene masterbatch in a blow - molding machine, and prepare an antibacterial polypropylene film through the processes of downward blowing, film coating, and winding.

7. The preparation method of an antibacterial polypropylene film according to claim 6, characterized in that, The barrel temperature of the blow - molding machine in Step 2 is 170 - 190 °C.

8. The preparation method of an antibacterial polypropylene film according to claim 6, characterized in that, Step 1 includes: Step 1 - 1: Mix the antibacterial agent and 8% - 10% by weight of polypropylene in the formula, melt and extrude them into pellets in a single - screw extruder to obtain antibacterial masterbatch; Step 1 - 2: Mix the antibacterial masterbatch obtained in Step 1 - 1 with the remaining raw materials, melt and extrude them into pellets in a single - screw extruder to obtain antibacterial polypropylene masterbatch.

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