A method for manufacturing an antibacterial polyethylene film

Abstract

This invention provides a method for manufacturing an antibacterial polyethylene film. The method involves placing polyethylene masterbatch coated with antibacterial microparticles into a ball mill, and using an external induction coil for induction heating. The induced heat from the conductive antibacterial microparticles is transferred to the coated polyethylene masterbatch, causing it to melt into a liquid. While the ball mill is rotating, the antibacterial microparticles, the molten polyethylene liquid, and the inorganic surfactant are uniformly mixed. The ball milling process forces the antibacterial microparticles to overcome the viscosity of the polyethylene liquid, resulting in forced diffusion and refinement. This allows the antibacterial microparticles to be uniformly dispersed in the molten polyethylene liquid during the grinding process, forming nanoparticles. The film is then directly introduced into a film-forming device to create a membrane. This method effectively reduces and eliminates sparse and agglomerated areas of nanoparticles in the antibacterial polyethylene material, ensuring uniform dispersion of nanoparticles within the polyethylene material and guaranteeing the stability and quality of the antibacterial polyethylene material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the polyethylene film manufacturing technology, and particularly relates to a manufacturing method of antibacterial polyethylene film. BACKGROUND

[0002] Polyethylene film is a plastic product frequently used in people's daily production and life process, and is used to make various packaging films and packaging bag products. Due to its light weight, impact resistance, stable chemical properties and other advantages, it is favored by people and has a very large demand in the consumer market.

[0003] With the improvement of the consumption level of various industrial and commercial products, the use of polyethylene film is more and more closely related to people's production and life. In order to make it more in line with the health standards in various specific situations, a certain amount of antibacterial agent is added when preparing the film body to obtain antibacterial composite products. The antibacterial agent composition penetrates into the microbial cell membrane to destroy its metabolic system, producing bacteriostatic or bactericidal effect. In order to ensure the distribution rate of antibacterial agent in micro size and achieve better antibacterial effect, nanometer antibacterial particles are usually dispersed in polyethylene resin to make master batch or film body at present. However, due to the high viscosity and poor flowability of polyethylene melt, and the influence of nanometer particle agglomeration, the nanometer particles cannot fully diffuse in each area in the polyethylene melt during the preparation of antibacterial composite materials, and are retained under the influence of the viscosity of the melt, which leads to uneven distribution of nanometer particles and agglomeration in local areas. Therefore, there are many sparse distribution areas and agglomeration distribution areas of nanometer particles in the prepared antibacterial material, neither of which can achieve good antibacterial effect, affecting the stability of polyethylene antibacterial material and product quality. Therefore, it is necessary to provide a targeted improvement scheme for the above defects. SUMMARY

[0004] In view of the problems in the prior art, the present application provides a manufacturing method of antibacterial polyethylene film, which effectively reduces and eliminates the sparse distribution area and agglomeration distribution area of nanometer particles in the polyethylene antibacterial material, ensures the uniform dispersion of nanometer particles in the polyethylene material, and guarantees the stability of the polyethylene antibacterial material and product quality.

[0005] The present application is implemented by the following technical scheme: a manufacturing method of antibacterial polyethylene film, comprising the following steps:

[0006] S1: Put the polyethylene master batch and antibacterial particle material into a container and mix them evenly, wherein the antibacterial particles are conductive, and the particle size of the antibacterial particles is ≤1mm. In the mixing process, the antibacterial particle material is adhered and wrapped on the surface of each polyethylene master batch by using the roughness of the surface of the polyethylene master batch;

[0007] S2: Place the polyethylene masterbatch material with antibacterial microparticles adhering to the surface into the ball mill. Set an induction coil on the outside of the non-metallic ball mill shell of the ball mill. Drive the induction coil to release an alternating magnetic field through an induction heating device, so that the antibacterial microparticles inside the ball mill shell are in an induction heating state. Limit the power of the induction heating device to ensure that the antibacterial microparticles are in a heated but non-melting state.

[0008] S3: The antibacterial microparticles in a heated state melt the polyethylene masterbatch into a liquid state. The ball mill is started to rotate the ball mill shell, so that the heated antibacterial microparticles are dispersed and contacted in various areas of the polyethylene masterbatch material. In this way, the heat of the antibacterial microparticles is evenly distributed in various areas of the polyethylene masterbatch material, so that all the polyethylene masterbatch material is in a molten state.

[0009] S4: Intermittently turn the induction heating device off and on, and repeat the intermittent operation of induction heating in this way to keep the temperature of the heating antibacterial particles and the inner cavity of the ball mill shell below the upper limit of the boiling point of polyethylene.

[0010] S5: Add an inorganic surfactant into the ball mill shell, continuously perform intermittent induction heating, and keep the ball mill running. As the ball mill body tumbles and the ball milling action reduces the particle size of the antibacterial particles, the operating power and duration of the induction heating device are reduced simultaneously, and the induction heating interval time is increased until nano-sized antibacterial particles are formed. These particles are then encapsulated by the inorganic surfactant and dispersed in the polyethylene melt by the ball milling action to obtain a high-temperature polyethylene particle dispersion.

[0011] S6: Extract the high-temperature polyethylene particle dispersion and add it to the feed end of the film forming equipment. Use the film forming equipment to form a thin film and obtain a polyethylene antibacterial film with uniformly dispersed antibacterial particles.

[0012] Preferably, in step S1, a rubber rod is used to stir the polyethylene masterbatch material in the container, so that electrons on the surface of the polyethylene masterbatch are transferred to the rubber rod, making the surface of the polyethylene masterbatch positively charged and generating electrostatic adsorption of antibacterial particles. During the stirring process, the surface roughness of the polyethylene masterbatch and the electrostatic adsorption effect are used to adhere the antibacterial particles to the surface of each polyethylene masterbatch.

[0013] Preferably, in step S6, the ball milling bodies in the ball mill shell are separated and blocked by a screen, allowing the high-temperature polyethylene particle dispersion to flow into the heat preservation box, and the high-temperature polyethylene particle dispersion is introduced into the film forming equipment by a screw conveyor.

[0014] Preferably, in step S6, the high-temperature polyethylene particle dispersion is added to a constant-temperature stirrer, and new high-temperature polyethylene melt is added at a mass ratio of more than 2. The mixture is stirred under the action of the constant-temperature stirrer to obtain a high-temperature polyethylene particle dispersion dilution. The high-temperature polyethylene particle dispersion dilution is then introduced into a film-forming device.

[0015] Preferably, the operating power of the induction heating device is 300W to 1200W.

[0016] Preferably, the operating current of the induction coil is 6A to 12A.

[0017] Preferably, the film-forming equipment is a blown film machine.

[0018] Preferably, the antibacterial microparticles are one or more of iron, copper, zinc, or their oxides.

[0019] Preferably, the inorganic surfactant is sodium trimetaphosphate.

[0020] Preferably, the material of the grinding ball shell is ceramic.

[0021] The beneficial effects of this invention are as follows: By placing polyethylene masterbatch coated with conductive antibacterial microparticles into a ball mill, and directly implementing induction heating with an external induction coil, the induced heat received by the conductive antibacterial microparticles is transferred to the polyethylene masterbatch they are coated with, thereby melting the coated polyethylene masterbatch into a liquid fluid. While the ball mill is rotating, the antibacterial microparticles, the polyethylene molten liquid, and the inorganic surfactant are uniformly mixed. The ball milling impact method allows the antibacterial microparticles to overcome the viscosity barrier of the polyethylene liquid and undergo forced diffusion and refinement. This allows the antibacterial microparticles to be uniformly dispersed in the polyethylene molten liquid in a synchronous manner during the process of being milled into nanoparticles by the ball mill. The coating effect of the surfactant further ensures the uniform distribution of the antibacterial microparticles in the weakly polar polyethylene molten liquid. This material is then directly introduced into a film-forming device to form a film, effectively reducing and eliminating the sparse distribution area and agglomeration area of ​​nanoparticles in the polyethylene antibacterial material, ensuring the uniform dispersion of nanoparticles in the polyethylene material, and guaranteeing the stability and product quality of the polyethylene antibacterial material. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the induction-ball milling composite operation state according to an embodiment of the present invention;

[0024] Figure 3 This is a comparison image of the encapsulation state of antibacterial microparticles in one embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the assembly structure of the induction coil and the ball mill shell in one embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of microscopic imaging of antibacterial microparticles in a polyethylene antibacterial film according to an embodiment of the present invention.

[0027] In the diagram: 10-mill shell, 10a-masterbatch material, 11-roller body, 12-mill body, 20-induction coil. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] like Figure 1 As shown, a method for manufacturing an antibacterial polyethylene film includes the following steps:

[0031] S1: Polyethylene masterbatch and copper antibacterial microparticles are placed in a container at a mass ratio of 25:1. The container is then placed in a mixer and stirred at 120 rad / min until homogeneous. The antibacterial microparticles, composed of copper particles, are selected with a particle size in the millimeter range (below 1 mm). During the mixing process, the surface roughness of the polyethylene masterbatch is utilized to adhere and coat the antibacterial microparticles onto the surface of each polyethylene masterbatch. Comparison of samples before and after coating is shown below. Figure 3 As shown; simultaneously, during the mixing process, a rubber rod is used to stir the polyethylene masterbatch material 10a in the container, causing electrons from the surface of the polyethylene masterbatch to transfer to the rubber rod, making the surface of the polyethylene masterbatch positively charged and generating electrostatic adsorption of antibacterial particles. During the stirring process, the surface roughness of the polyethylene masterbatch and electrostatic adsorption are used to adhere the antibacterial particles to the surface of each polyethylene masterbatch. Under the combined action of electrostatic adsorption and surface roughness, it is ensured that the antibacterial material is fully wrapped and adhered to the surface of the polyethylene masterbatch, forming a mixture as shown. Figure 3 The particle encapsulation state shown in the sample on the right;

[0032] S2: As Figure 2 , Figure 4 As shown, polyethylene masterbatch material 10a with antibacterial microparticles adhering to its surface is placed into a ball mill. An induction coil 20 is set on the outside of the ceramic ball mill shell 10 of the ball mill. The ball mill shell 10 is supported by a non-metallic roller 11 to ensure that the relevant components are not subject to electromagnetic interference. The induction coil 20 is driven by an induction heating device to release an alternating magnetic field, ensuring that the working power of the induction heating device is 1200W and the working current of the induction coil 20 is 12A, so that the antibacterial microparticles in the ball mill shell 10 are in an induction heating state. By limiting the power of the induction heating device to no more than 1200W, it is ensured that the antibacterial microparticles are in a heated but non-melting state, thereby preventing the possibility of the masterbatch evaporating due to excessive temperature. In this way, the induction heat received by the conductive antibacterial microparticles is conducted to the polyethylene masterbatch it encapsulates.

[0033] S3: The heated antibacterial microparticles melt the polyethylene masterbatch encapsulated in the process into a liquid state. The ball mill is then started to rotate the ball mill shell 10, causing the heated antibacterial microparticles to disperse and contact various areas of the polyethylene masterbatch material 10a. This uniformly distributes the heat of the antibacterial microparticles throughout the polyethylene masterbatch material 10a, ensuring that all of the polyethylene masterbatch material 10a is in a molten state. This also ensures that the nanoparticles can be fully mixed with the polyethylene material during the subsequent ball milling process to smaller particle sizes.

[0034] S4: Intermittently turn the induction heating device off and on, and repeat the intermittent operation of induction heating in this way to keep the temperature of the heating antibacterial particles and the inner cavity of the ball mill shell 10 below the upper limit of the boiling point of polyethylene until the working power of the induction heating device is reduced to 340w and the circuit of the induction coil 20 is reduced to 6.5A, so as to maintain the melting state of polyethylene and prevent the polyethylene material from evaporating due to excessive temperature.

[0035] S5: Add 5% sodium trimetaphosphate inside the ball mill shell 10. Utilize the high-temperature resistance of its inorganic surfactant to ensure its nano-encapsulation function. Continuously implement intermittent induction heating while maintaining the ball mill operation. Through ball milling impact, the antibacterial microparticles overcome the viscosity barrier of the polyethylene liquid, resulting in forced diffusion and refinement. As the ball mill body 12 tumbles and mills, the particle size of the antibacterial microparticles continuously decreases. Simultaneously, reduce the operating power and duration of the induction heating device and increase the induction heating interval until nano-sized antibacterial microparticles are formed and encapsulated by the inorganic surfactant. Ball milling disperses the particles in the molten polyethylene to obtain a high-temperature polyethylene particle dispersion. Since induction heating, nano-ball milling, and multiphase mixing are carried out simultaneously, the agglomeration of nano-antibacterial particles can be effectively prevented. The antibacterial particles are uniformly dispersed in the molten polyethylene in a synchronous manner during the process of being milled into nanoparticles by the ball mill 12 (at this time, polyethylene, with its weak polarity, serves as the carrier liquid in the multiphase mixture). The encapsulation effect of surfactants further ensures the uniform distribution of antibacterial particles in the weakly polar molten polyethylene, thereby obtaining an antibacterial liquid with good dispersibility.

[0036] S6: Using a screen, the ball mill body 12 in the ball mill shell 10 is separated and blocked, allowing the high-temperature polyethylene particle dispersion to flow into the heat preservation box. A screw conveyor is used to guide the high-temperature polyethylene particle dispersion into the blown film machine. The heat preservation box and the outer wall of the conveyor can be equipped with a heating belt device to ensure the high temperature and dispersion state of the polyethylene particle dispersion. In this state, it is directly introduced into the feed end of the blown film machine. After blowing, a polyethylene antibacterial film with uniformly dispersed antibacterial particles is obtained. Because the introduced antibacterial dispersion has good dispersibility, it can effectively weaken and eliminate the sparse distribution area and agglomeration distribution area of ​​nanoparticles in the polyethylene antibacterial material, thereby making a polyethylene antibacterial film with uniformly dispersed antibacterial particles.

[0037] likeFigure 5 As shown in the microscopic imaging, observed through a 150,000x EBC coating microscope, the antibacterial microparticles (copper nanoparticles) in the antibacterial film are uniformly distributed, with small particle size and no obvious agglomeration or sparse areas. This ensures that the antibacterial nanoparticles have a good degree of dispersion in the polyethylene product film. Utilizing the antibacterial properties of the copper nanoparticles and their uniform dispersion in the film, the film can inhibit or kill various pathogenic microorganisms such as bacteria, yeast, and viruses, thus ensuring the stability of the polyethylene antibacterial film material and the product quality.

[0038] Example 2

[0039] The difference between this embodiment and Embodiment 1 lies in the selection of antibacterial microparticles of different particle sizes and the adaptation process, making it suitable for energy-saving production needs. The embodiment includes the following steps:

[0040] S1: Put polyethylene masterbatch and copper antibacterial microparticles into a container at a mass ratio of 25:1. Place the container into a mixer and mix at a speed of 100 rad / min. The antibacterial microparticles composed of copper particles are selected to have a particle size of micron (less than 1 μm). During the mixing process, the surface roughness of the polyethylene masterbatch is used to adhere and coat the antibacterial microparticles onto the surface of each polyethylene masterbatch.

[0041] S2: The antibacterial microparticle polyethylene masterbatch material 10a is placed into a ball mill. An induction coil 20 is set on the outside of the ceramic ball mill shell 10 of the ball mill. The ball mill shell 10 is supported by a non-metallic roller 11 to ensure that the relevant components are not subject to electromagnetic interference. The induction coil 20 is driven by an induction heating device to release an alternating magnetic field, ensuring that the working power of the induction heating device is 900W and the working current of the induction coil 20 is 7.5A, so that the antibacterial microparticles in the ball mill shell 10 are in an induction heating state. By limiting the power of the induction heating device to no more than 900W, it is ensured that the antibacterial microparticles are in a heated but non-melting state, thereby preventing the possibility of the masterbatch evaporating due to excessive temperature. In this way, the induction heat received by the conductive antibacterial microparticles is conducted to the polyethylene masterbatch it encapsulates.

[0042] S3: The heated antibacterial microparticles melt the polyethylene masterbatch encapsulated in the process into a liquid state. The ball mill is then started to rotate the ball mill shell 10, causing the heated antibacterial microparticles to disperse and contact various areas of the polyethylene masterbatch material 10a. This uniformly distributes the heat of the antibacterial microparticles throughout the polyethylene masterbatch material 10a, ensuring that all of the polyethylene masterbatch material 10a is in a molten state. This also ensures that the nanoparticles can be fully mixed with the polyethylene material during the subsequent ball milling process to smaller particle sizes.

[0043] S4: Intermittently turn the induction heating device off and on, and repeat the intermittent operation of induction heating in this way to keep the temperature of the heating antibacterial particles and the inner cavity of the ball mill shell 10 below the upper limit of the boiling point of polyethylene until the working power of the induction heating device is reduced to 300w and the circuit of the induction coil 20 is reduced to 6A, so as to maintain the melting state of polyethylene and prevent the polyethylene material from evaporating due to excessive temperature.

[0044] S5: Add 5% sodium trimephosphate to the ball mill shell 10. Utilize the high-temperature resistance of its inorganic surfactant to ensure its nano-encapsulation function. Continuously implement intermittent induction heating while keeping the ball mill running. As the ball mill body 12 tumbles and mills, the particle size of the antibacterial particles decreases. Simultaneously reduce the operating power and duration of the induction heating device and increase the induction heating interval until nano-sized antibacterial particles are formed. These particles are then encapsulated by the inorganic surfactant and dispersed in the polyethylene melt by the ball milling action, resulting in a high-temperature polyethylene particle dispersion. Since induction heating, nano-ball milling, and multiphase mixing are performed simultaneously, the agglomeration of the nano-antibacterial particles can be effectively prevented. The antibacterial particles are directly and uniformly dispersed in the polyethylene melt in a synchronous manner during the process of being milled by the ball mill body 12 to form nanoparticles. The encapsulation effect of the surfactant further ensures the uniform distribution of the antibacterial particles in the weakly polar polyethylene melt, thereby obtaining an antibacterial liquid with good dispersibility.

[0045] S6: A screw conveyor is used to introduce the high-temperature polyethylene particle dispersion into the blown film machine to ensure the high temperature and dispersion state of the polyethylene particle dispersion. In this state, it is directly introduced into the feed end of the blown film machine to obtain a polyethylene antibacterial film with uniformly dispersed antibacterial particles. Because the introduced antibacterial dispersion has good dispersibility and is always in a hot flow state, it can effectively reduce and eliminate the sparse distribution area and agglomeration area of ​​nanoparticles in the polyethylene antibacterial material. This produces a polyethylene antibacterial film with uniformly dispersed antibacterial particles, ensuring the uniform dispersion of nanoparticles in the polyethylene film and guaranteeing the stability and product quality of the polyethylene antibacterial material.

[0046] Example 3

[0047] The difference between this embodiment and Embodiment 1 lies in the use of antimicrobial microparticles of different materials, making it suitable for different packaging applications. The embodiment includes the following steps:

[0048] S1: Put polyethylene masterbatch and zinc antibacterial microparticles into a container at a mass ratio of 22:1. Place the container into a mixer and mix at a speed of 120 rad / min. The antibacterial microparticles composed of zinc particles are selected with a particle size of millimeters (less than 1 mm). During the mixing process, the surface roughness of the polyethylene masterbatch is used to adhere and coat the antibacterial microparticles onto the surface of each polyethylene masterbatch.

[0049] S2: The antibacterial microparticle polyethylene masterbatch material 10a is placed into a ball mill. An induction coil 20 is set on the outside of the ceramic ball mill shell 10 of the ball mill. The ball mill shell 10 is supported by a non-metallic roller 11 to ensure that the relevant components are not subject to electromagnetic interference. The induction coil 20 is driven by an induction heating device to release an alternating magnetic field, ensuring that the working power of the induction heating device is 1200W and the working current of the induction coil 20 is 12A, so that the antibacterial microparticles in the ball mill shell 10 are in an induction heating state. By limiting the power of the induction heating device to no more than 1200W, it is ensured that the antibacterial microparticles are in a heated but non-melting state, thereby preventing the possibility of the masterbatch evaporating due to excessive temperature. In this way, the induction heat received by the conductive antibacterial microparticles is conducted to the polyethylene masterbatch it encapsulates.

[0050] S3: The heated antibacterial microparticles melt the polyethylene masterbatch encapsulated in the process into a liquid state. The ball mill is then started to rotate the ball mill shell 10, causing the heated antibacterial microparticles to disperse and contact various areas of the polyethylene masterbatch material 10a. This uniformly distributes the heat of the antibacterial microparticles throughout the polyethylene masterbatch material 10a, ensuring that all of the polyethylene masterbatch material 10a is in a molten state. This also ensures that the nanoparticles can be fully mixed with the polyethylene material during the subsequent ball milling process to smaller particle sizes.

[0051] S4: Intermittently turn the induction heating device off and on, and repeat the intermittent operation of induction heating in this way to keep the temperature of the heating antibacterial particles and the inner cavity of the ball mill shell 10 below the upper limit of the boiling point of polyethylene until the working power of the induction heating device is reduced to 340w and the circuit of the induction coil 20 is reduced to 6.5A, so as to maintain the melting state of polyethylene and prevent the polyethylene material from evaporating due to excessive temperature.

[0052] S5: Add 5% sodium trimephosphate to the ball mill shell 10. Utilize the high-temperature resistance of its inorganic surfactant to ensure its nano-encapsulation function. Continuously implement intermittent induction heating while keeping the ball mill running. As the ball mill body 12 tumbles and mills, the particle size of the antibacterial particles decreases. Simultaneously reduce the operating power and duration of the induction heating device and increase the induction heating interval until nano-sized antibacterial particles are formed. These particles are then encapsulated by the inorganic surfactant and dispersed in the polyethylene melt by the ball milling action, resulting in a high-temperature polyethylene particle dispersion. Since induction heating, nano-ball milling, and multiphase mixing are performed simultaneously, the agglomeration of the nano-antibacterial particles can be effectively prevented. The antibacterial particles are directly and uniformly dispersed in the polyethylene melt in a synchronous manner during the process of being milled by the ball mill body 12 to form nanoparticles. The encapsulation effect of the surfactant further ensures the uniform distribution of the antibacterial particles in the weakly polar polyethylene melt, thereby obtaining an antibacterial liquid with good dispersibility.

[0053] S6: A screw conveyor is used to introduce the high-temperature polyethylene particle dispersion into the blown film machine, ensuring the high temperature and dispersion state of the polyethylene particle dispersion. In this state, it is directly introduced into the feed end of the blown film machine to obtain a polyethylene antibacterial film with uniformly dispersed antibacterial particles. Due to the good dispersibility of the introduced antibacterial dispersion and its constant hot flow state, the sparse distribution area and agglomeration area of ​​nano zinc particles in the polyethylene antibacterial material can be effectively reduced and eliminated. This produces a polyethylene antibacterial film with uniformly dispersed antibacterial particles, ensuring the uniform dispersion of nano zinc particles in the polyethylene film, guaranteeing the stability of the polyethylene antibacterial material and product quality. At the same time, the properties of zinc element to inhibit harmful bacteria such as Staphylococcus aureus and Escherichia coli can be utilized, making it suitable for antibacterial packaging applications with related bacterial colonies.

[0054] Example 4

[0055] The difference between this embodiment and Embodiment 1 is the addition of a dispersion dilution step, thereby improving the thermal efficiency of the induction melting process and adapting to packaging products with different antibacterial specifications. The steps include:

[0056] S1: Put polyethylene masterbatch and copper antibacterial microparticles into a container at a mass ratio of 8:1. Place the container into a mixer and mix at a speed of 120 rad / min. The antibacterial microparticles composed of copper particles are selected with a particle size of millimeters (less than 1 mm). During the mixing process, the surface roughness of the polyethylene masterbatch is used to adhere and coat the antibacterial microparticles onto the surface of each polyethylene masterbatch.

[0057] S2: As Figure 2 , Figure 4 As shown, polyethylene masterbatch material 10a with antibacterial microparticles adhering to its surface is placed into a ball mill. An induction coil 20 is set on the outside of the ceramic ball mill shell 10 of the ball mill. The ball mill shell 10 is supported by a non-metallic roller 11 to ensure that the relevant components are not subject to electromagnetic interference. The induction coil 20 is driven by an induction heating device to release an alternating magnetic field, ensuring that the working power of the induction heating device is 1200W and the working current of the induction coil 20 is 12A, so that the antibacterial microparticles in the ball mill shell 10 are in an induction heating state. By limiting the power of the induction heating device to no more than 1200W, it is ensured that the antibacterial microparticles are in a heated but non-melting state, thereby preventing the possibility of the masterbatch evaporating due to excessive temperature. In this way, the induction heat received by the conductive antibacterial microparticles is conducted to the polyethylene masterbatch it encapsulates.

[0058] S3: The heated antibacterial microparticles melt the polyethylene masterbatch encapsulated in the heat into a liquid state. Since the proportion of copper microparticles used in step S1 is relatively large, their contact density with the polyethylene masterbatch is high, which can quickly conduct heat to make it fully form a liquid. Simultaneously, the ball mill is started to rotate the ball mill shell 10, so that the heated antibacterial microparticles are dispersed and contacted in various areas of the polyethylene masterbatch material 10a. In this way, the heat of the antibacterial microparticles is evenly distributed in various areas of the polyethylene masterbatch material 10a, so that all the polyethylene masterbatch material 10a is in a molten state. This ensures that the nanoparticles can be fully mixed with the polyethylene material during the subsequent ball milling to a smaller particle size.

[0059] S4: Intermittently turn the induction heating device off and on, and repeat the intermittent operation of induction heating in this way to keep the temperature of the heating antibacterial particles and the inner cavity of the ball mill shell 10 below the upper limit of the boiling point of polyethylene until the working power of the induction heating device is reduced to 340w and the circuit of the induction coil 20 is reduced to 6.5A, so as to maintain the melting state of polyethylene and prevent the polyethylene material from evaporating due to excessive temperature.

[0060] S5: Add 5% sodium tripolyphosphate to the ball mill shell 10. Utilize its high-temperature resistance as an inorganic surfactant to ensure its nano-encapsulation function. Continuously implement intermittent induction heating while maintaining the ball mill operation. Through ball milling impact, the antibacterial microparticles overcome the viscosity barrier of polyethylene, resulting in forced diffusion and refinement. As the ball mill body 12 tumbles and mills, the particle size of the antibacterial microparticles continuously decreases. Simultaneously, reduce the operating power and duration of the induction heating device and increase the induction heating interval until nano-sized antibacterial microparticles are formed. These microparticles are then dispersed in the molten polyethylene liquid by the inorganic surfactant encapsulation and ball milling action, resulting in a high-temperature polyethylene particle dispersion. Due to the induction... Heating, nano-ball milling, and multiphase mixing are performed simultaneously, which effectively prevents the agglomeration of nano-antibacterial particles. This allows the antibacterial microparticles to be uniformly dispersed in the polyethylene melt in a synchronous manner during the process of being milled into nanoparticles by the ball mill 12 (at this time, polyethylene, with its weak polarity, serves as the carrier liquid in the multiphase mixture). Meanwhile, since a large proportion of copper microparticles are used in step S1, the copper solid phase content is relatively large, which enhances the impact of ball milling and reduces the resistance of the polyethylene melt. With the help of the surfactant's encapsulation effect, the uniform distribution of antibacterial microparticles in the weakly polar polyethylene melt is further ensured, thereby obtaining a highly concentrated antibacterial solution with good dispersibility.

[0061] S6: Add the high-temperature polyethylene particle dispersion to a constant-temperature stirrer, and replenish with new high-temperature polyethylene melt at a mass ratio of 2 to 12 times. The upper and lower limits of the mass ratio are adjusted inversely to the antibacterial standard used in the antibacterial film product. In this embodiment, the mass ratio is 7 times. Mix under the stirring action of the constant-temperature stirrer to prevent agglomeration under the protection of the surfactant coating layer. The resulting high-temperature polyethylene particle dispersion dilution is introduced into the film-forming equipment to produce a polyethylene antibacterial film with uniformly dispersed antibacterial particles. Because a high proportion of copper particles is used in the induction melting and ball milling operations in the early stage, the thermal efficiency of the induction melting operation and the ball milling efficiency can be effectively improved. Then, the antibacterial film product of the required specifications is obtained under the protection of the surfactant, improving production efficiency and the applicability of antibacterial specifications.

[0062] The above description is only one of the preferred embodiments of the present invention and is not intended to limit the present invention in any way. For those skilled in the art, other equivalent substitutions can be made to the embodiments, and these substitutions should be included within the protection scope of the present invention as long as they conform to the feature scope defined in the claims.

Claims

1. A method of manufacturing an antibacterial polyethylene film, characterized by: The method comprises the following steps: S1: Put polyethylene master batch and antibacterial micro-particle material into a container and mix them, wherein the antibacterial micro-particle is conductive, and the particle size of the antibacterial micro-particle is less than or equal to 1 mm. During the mixing process, the antibacterial micro-particle material is adhered to and wrapped around the surface of each polyethylene master batch by using the roughness of the surface of the polyethylene master batch; S2: Put the polyethylene master batch material with the antibacterial micro-particle adhered to its surface into a ball mill. An induction coil is arranged outside the non-metallic ball mill shell. The induction coil is driven by an induction heating device to release an alternating magnetic field, so that the antibacterial micro-particle in the ball mill shell is in an induced heating state. The power of the induction heating device is limited to ensure that the antibacterial micro-particle is in a heated and non-melting state; S3: The polyethylene master batch wrapped by the antibacterial micro-particle in the heated state is melted into a liquid state. The ball mill is started to rotate the ball mill shell, so that the antibacterial micro-particle in the heated state is dispersed and contacted with each region in the polyethylene master batch material. In this way, the heat of the antibacterial micro-particle is uniformly dispersed in each region of the polyethylene master batch material, so that all the polyethylene master batch material is in a melted state; S4: The induction heating device is turned off and started at intervals. In this way, the interval operation of induction heating is repeatedly implemented, so that the temperature of the heated antibacterial micro-particle and the inner cavity of the ball mill shell is always lower than the upper limit of the boiling point of polyethylene; S5: Add inorganic surfactant into the ball mill shell. Continue to implement the interval operation of induction heating, and keep the ball mill running. The antibacterial micro-particle is reduced in size by the rolling and grinding action of the ball mill body. At the same time, the operation power and time of the induction heating device are reduced, and the induction heating interval time is increased, until the nanoscale antibacterial micro-particle material is formed and is wrapped by the inorganic surfactant and dispersed in the polyethylene melting liquid by the action of the ball mill, to obtain a high-temperature polyethylene particle dispersion liquid; S6: Extract the high-temperature polyethylene particle dispersion liquid and add it to the feeding end of a film forming equipment. Use the film forming equipment to make a film body, to obtain a polyethylene antibacterial film with uniformly dispersed antibacterial micro-particles.

2. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: In step S1, a rubber rod is used to stir the polyethylene master batch material in the container, so that the electrons on the surface of the polyethylene master batch are transferred to the rubber rod, making the surface of the polyethylene master batch show positive electrification and produce electrostatic adsorption effect on the antibacterial micro-particles. During the stirring process, the antibacterial micro-particle material is adhered to the surface of each polyethylene master batch by using the roughness of the surface of the polyethylene master batch and the electrostatic adsorption effect.

3. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: In step S6, a screw conveyor is used to guide the high-temperature polyethylene particle dispersion liquid into the film forming equipment.

4. The method of producing an antibacterial polyethylene film according to claim 1, characterized by: In step S6, the high-temperature polyethylene particle dispersion liquid is added into a constant temperature stirrer, supplemented with new high-temperature polyethylene melting liquid with a mass ratio of more than 2 times, and mixed under the stirring action of the constant temperature stirrer, to obtain a high-temperature polyethylene particle dispersion dilution liquid. The high-temperature polyethylene particle dispersion dilution liquid is guided into the film forming equipment.

5. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The working power of the induction heating device is 300 W to 1200 W.

6. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The working current of the induction coil is 6 A to 12 A.

7. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The film forming equipment is a film blowing machine.

8. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The type of antibacterial micro-particle is one or more of iron, copper, zinc or their oxides.

9. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The inorganic surfactant is sodium trimetaphosphate.

10. The method of manufacturing an antibacterial polyethylene film according to claim 1, characterized by: The material of the ball mill shell is ceramic.

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