An antibacterial BOPP film and preparation method thereof

Abstract

The present invention provides an antibacterial BOPP film and a preparation method thereof, wherein the BOPP film comprises an antibacterial base film, a reinforced antibacterial upper surface film, and a reinforced antibacterial lower surface film, wherein the antibacterial base film is located between the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film. The antibacterial BOPP film of the present invention is composed of an antibacterial base film, a reinforced antibacterial upper surface film, and a reinforced antibacterial lower surface film, wherein 1,2-benzisothiazolin-3-one antibacterial agent is added to the antibacterial base film, the reinforced antibacterial upper surface film, and the reinforced antibacterial lower surface film, thereby forming an antibacterial pathway vertically and improving the antibacterial efficiency; meanwhile, modified silicone microspheres are added to the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film, so that the antibacterial agent is evenly dispersed in the system, thereby improving the antibacterial performance of the film layer as a whole.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and in particular relates to an antibacterial BOPP film and a preparation method thereof. Background Art

[0002] Biaxially oriented polypropylene (BOPP) film has the advantages of high strength, high transparency, high gloss, high stiffness, good thermal stability and non-toxicity. It is of high quality and moderate price. It is widely used in packaging of food, beverage, cigarette, clothing and other industries, and has rapidly occupied the plastic packaging market.

[0003] The antibacterial effect of the films currently used for daily hygiene products and food packaging is not ideal, especially for medicine and food packaging, which require a certain barrier function. Summary of the invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes an antibacterial BOPP film and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] The present invention provides an antibacterial BOPP film, the BOPP film comprises an antibacterial base film, a reinforced antibacterial upper surface film, and a reinforced antibacterial lower surface film, wherein the antibacterial base film is located between the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film;

[0007] The enhanced antibacterial upper surface film is made of the following raw materials in parts by weight:

[0008] Polypropylene 80-99 parts, antibacterial agent 0.001-1 parts, modified silicone microspheres 1-20 parts;

[0009] The enhanced antibacterial lower surface film is made of the following raw materials in parts by weight:

[0010] Polypropylene 90-99 parts, antibacterial agent 0.001-1 parts, modified silicone microspheres 1-10 parts.

[0011] Furthermore, the antibacterial agent of the enhanced antibacterial upper surface film is the same as or different from the antibacterial agent of the enhanced antibacterial lower surface film.

[0012] Preferably, the antibacterial agent of the enhanced antibacterial upper surface film is 1,2-benzisothiazolin-3-one; and the antibacterial agent of the enhanced antibacterial lower surface film is 1,2-benzisothiazolin-3-one.

[0013] Furthermore, the modified silicone microspheres for strengthening the antibacterial upper surface film are the same as the modified silicone microspheres for strengthening the antibacterial lower surface film.

[0014] Furthermore, the modified organic silicon microspheres are prepared by a method comprising the following steps: subjecting the organic silicon microspheres to alkali treatment, and uniformly mixing the treated organic silicon microspheres with a cross-linking component to obtain modified organic silicon microspheres.

[0015] Furthermore, the alkali treatment step uses a sodium hydroxide solution with a mass concentration of 10-20%, and the alkali treatment time is 0.5-5 hours; the mass ratio of the organic silicon microspheres to the cross-linking component is 1:0.01-1.

[0016] Further, the cross-linking component is prepared by a method comprising the following steps:

[0017] Step 1: adding an acrylic acid solution to a sodium hydroxide solution, mixing uniformly to obtain a primary solution, adding an acrylamide solution to the primary solution, mixing uniformly under heating conditions to obtain a secondary solution, and adding an acrylonitrile solution to the secondary solution, mixing uniformly under heating conditions to obtain a tertiary solution;

[0018] Step 2: adding ammonium persulfate solution and sodium bisulfite solution to the tertiary solution, mixing them evenly under heating conditions to obtain a fourth solution, cooling to room temperature after complete reaction, and dropping sodium hydroxide solution into the fourth solution until the pH value of the solution reaches 7-8, then stopping the dropping, and then filtering to obtain a cross-linked component.

[0019] Further, the concentration of the acrylic acid solution in step 1 is 1-5 g / mL; the concentration of the sodium hydroxide solution in step 1 is 0.01-0.1 g / mL; the concentration of the acrylamide solution in step 1 is 0.1-1 g / mL; the concentration of the acrylonitrile solution in step 1 is 1-5 g / mL; the concentration of the ammonium persulfate solution in step 2 is 0.001-0.01 g / mL; the concentration of the sodium bisulfite solution in step 2 is 0.001-0.01 g / mL; the concentration of the sodium hydroxide solution in step 2 is 0.001-0.01 g / mL.

[0020] Preferably, the cross-linking component is prepared by a method comprising the following steps:

[0021] Step 1: 80g of sodium hydroxide and 1500g of deionized water are mixed uniformly to obtain a sodium hydroxide solution, 180g of acrylic acid is dissolved in 200g of deionized water to obtain an acrylic acid solution, the acrylic acid solution is added to the sodium hydroxide solution, and the mixture is uniformly mixed to obtain a primary solution, 94g of acrylamide is dissolved in 200g of deionized water to obtain an acrylamide solution, the acrylamide solution is added to the primary solution, and the mixture is stirred for 1-2 hours at a temperature of 50-60°C to obtain a secondary solution, 66g of acrylonitrile is dissolved in 50g of deionized water to obtain an acrylonitrile solution, the acrylonitrile solution is added to the secondary solution, and the mixture is stirred for 0.1-1 hour at a temperature of 50-60°C to obtain a tertiary solution;

[0022] Step 2 is to dissolve 0.075g of ammonium persulfate in 15g of deionized water to obtain an ammonium persulfate solution, dissolve 0.0375g of sodium bisulfite in 7.5g of deionized water to obtain a sodium bisulfite solution, add the ammonium persulfate solution and the sodium bisulfite solution to the tertiary solution, stir for 12-36 hours at a temperature of 50-60°C, cool to room temperature after complete reaction to obtain a fourth solution, dissolve 19.12g of NaOH in 3300g of deionized water to obtain a sodium hydroxide solution, add the sodium hydroxide solution dropwise to the fourth solution until the pH of the solution is adjusted to 7.6, and filter using a 100-500 mesh filter paper to obtain a cross-linking component.

[0023] After the alkali treatment, the roughness of the surface of the silicone microspheres is increased, which facilitates the uniform combination with the antibacterial agent in the antibacterial upper surface film through the action of the cross-linking component, thereby improving the antibacterial properties of the upper surface film. At the same time, under the action of the cross-linking component, the antibacterial upper surface film is improved in its binding with the antibacterial base film, and combined with the antibacterial agent in the antibacterial base film, an antibacterial channel is formed, thereby improving the overall antibacterial ability of the film.

[0024] Furthermore, the antibacterial base film is made of the following raw materials in parts by weight: 90-99 parts of polypropylene, 1-9 parts of nano titanium dioxide, and 0.001-1 parts of antibacterial agent. Nano titanium dioxide fiber can improve the elastic modulus and heat shrinkage of BOPP film, and improve the mechanical properties of BOPP film.

[0025] The present invention also provides a method for preparing an antibacterial BOPP film, comprising the following steps:

[0026] Step 1 is to blend and extrude polypropylene, nano titanium dioxide and an antibacterial agent to obtain an antibacterial base film;

[0027] Step 2 is to blend and extrude polypropylene, antibacterial agent and modified silicone microspheres to obtain a reinforced antibacterial upper surface film;

[0028] Step 3 is to blend and extrude polypropylene, antibacterial agent and modified silicone microspheres to obtain a reinforced antibacterial lower surface film;

[0029] Step 4 is to feed the antibacterial base film into the main extruder for melting, and to place the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film into two auxiliary extruders for melting, and to extrude through a three-layer structure die head for biaxial stretching to obtain the antibacterial BOPP film.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The antibacterial BOPP film described in the present invention consists of an antibacterial base film, a reinforced antibacterial upper surface film and a reinforced antibacterial lower surface film. 1,2-benzisothiazolin-3-one antibacterial agent is added to the antibacterial base film, the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film, and an antibacterial pathway is formed in the vertical direction, thereby improving the antibacterial efficiency. At the same time, modified silicone microspheres are added to the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film, and the silicone microspheres are combined with the antibacterial agent through a cross-linking group. The antibacterial agent is uniformly dispersed in the system through the silicone microspheres, thereby improving the overall antibacterial performance of the film layer. DETAILED DESCRIPTION

[0032] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0033] The cross-linking components in the embodiments and comparative examples of the present invention are prepared by a method comprising the following steps:

[0034] (1) 80 g of sodium hydroxide and 1500 g of deionized water were mixed uniformly to obtain a sodium hydroxide solution, 180 g of acrylic acid was dissolved in 200 g of deionized water to obtain an acrylic acid solution, the acrylic acid solution was added to the sodium hydroxide solution, and the mixture was uniformly mixed to obtain a primary solution, 94 g of acrylamide was dissolved in 200 g of deionized water to obtain an acrylamide solution, the acrylamide solution was added to the primary solution, and the mixture was stirred at a temperature of 50° C. for 2 hours to obtain a secondary solution, 66 g of acrylonitrile was dissolved in 50 g of deionized water to obtain an acrylonitrile solution, the acrylonitrile solution was added to the secondary solution, and the mixture was stirred at a temperature of 50° C. for 1 hour to obtain a tertiary solution;

[0035] Step 2 is to dissolve 0.075g of ammonium persulfate in 15g of deionized water to obtain an ammonium persulfate solution, dissolve 0.0375g of sodium bisulfite in 7.5g of deionized water to obtain a sodium bisulfite solution, add the ammonium persulfate solution and the sodium bisulfite solution to the tertiary solution, stir for 24 hours at a temperature of 50°C, cool to room temperature after complete reaction, obtain a fourth solution, dissolve 19.12g of NaOH in 3300g of deionized water to obtain a sodium hydroxide solution, add the sodium hydroxide solution dropwise to the fourth solution until the pH of the solution is adjusted to 7.6, and filter using a 400-mesh filter paper to obtain a cross-linking component.

[0036] The present invention will be described in detail below with reference to the embodiments.

[0037] Example 1

[0038] A method for preparing an antibacterial BOPP film comprises the following steps:

[0039] (1) Soaking the organosilicon microspheres in a sodium hydroxide solution having a mass concentration of 10% for 10 hours, then taking out the organosilicon microspheres and uniformly mixing them with 5% (mass percentage) of a cross-linking component to obtain modified organosilicon microspheres;

[0040] (2) 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are co-blended and extruded to obtain an antibacterial base film; 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film; 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film; the antibacterial base film is fed into a main extruder for melting; the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die head, and biaxially stretched to obtain the antibacterial BOPP film.

[0041] Example 2

[0042] A method for preparing an antibacterial BOPP film comprises the following steps:

[0043] (1) Soaking the organosilicon microspheres in a sodium hydroxide solution having a mass concentration of 10% for 10 hours, then taking out the organosilicon microspheres, and uniformly mixing them with 20% (mass percentage) of a cross-linking component to obtain modified organosilicon microspheres;

[0044] (2) 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are co-blended and extruded to obtain an antibacterial base film; 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film; 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film; the antibacterial base film is fed into a main extruder for melting; the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die head, and biaxially stretched to obtain the antibacterial BOPP film.

[0045] Example 3

[0046] A method for preparing an antibacterial BOPP film comprises the following steps:

[0047] (1) Soaking the organosilicon microspheres in a sodium hydroxide solution having a mass concentration of 10% for 10 hours, then taking out the organosilicon microspheres and uniformly mixing them with 5% (mass percentage) of a cross-linking component to obtain modified organosilicon microspheres;

[0048] (2) 90 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are co-blended and extruded to obtain an antibacterial base film; 90 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film; 90 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film; the antibacterial base film is fed into a main extruder for melting; the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die head, and biaxially stretched to obtain the antibacterial BOPP film.

[0049] Comparative Example 1

[0050] A method for preparing an antibacterial BOPP film comprises the following steps:

[0051] (1) Soaking the organosilicon microspheres in a sodium hydroxide solution having a mass concentration of 10% for 10 hours, then taking out the organosilicon microspheres and mixing them evenly with 5% (mass percentage) of diisopropylbenzene peroxide to obtain modified organosilicon microspheres;

[0052] (2) 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are co-blended and extruded to obtain an antibacterial base film; 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film; 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film; the antibacterial base film is fed into a main extruder for melting; the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die head, and biaxially stretched to obtain the antibacterial BOPP film.

[0053] Comparative Example 2

[0054] A method for preparing an antibacterial BOPP film comprises the following steps:

[0055] (1) uniformly mixing the silicone microspheres and the cross-linking component in a mass ratio of 1:0.05 to obtain modified silicone microspheres;

[0056] (2) 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are co-blended and extruded to obtain an antibacterial base film; 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film; 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film; the antibacterial base film is fed into a main extruder for melting; the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die head, and biaxially stretched to obtain the antibacterial BOPP film.

[0057] Comparative Example 3

[0058] A method for preparing an antibacterial BOPP film comprises the following steps:

[0059] 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are blended and extruded to obtain an antibacterial base film, 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of silicone microspheres are blended and extruded to obtain a reinforced antibacterial upper surface film, 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of silicone microspheres are blended and extruded to obtain a reinforced antibacterial lower surface film, the antibacterial base film is sent to a main extruder for melting, the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die, and biaxially stretched to obtain the antibacterial BOPP film.

[0060] Comparative Example 4

[0061] A method for preparing an antibacterial BOPP film comprises the following steps:

[0062] 95 parts of polypropylene, 5 parts of nano-titanium dioxide and 0.1 parts of antibacterial agent are blended and extruded to obtain an antibacterial base film, 85 parts of polypropylene and 0.1 parts of 1,2-benzisothiazolin-3-one are blended and extruded to obtain a reinforced antibacterial upper surface film, 95 parts of polypropylene and 0.1 parts of 1,2-benzisothiazolin-3-one are blended and extruded to obtain a reinforced antibacterial lower surface film, the antibacterial base film is sent to a main extruder for melting, the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die, and biaxially stretched to obtain the antibacterial BOPP film.

[0063] Comparative Example 5

[0064] A method for preparing an antibacterial BOPP film comprises the following steps:

[0065] (1) Soaking the organosilicon microspheres in a sodium hydroxide solution having a mass concentration of 10% for 10 hours, then taking out the organosilicon microspheres and uniformly mixing them with 5% (mass percentage) of a cross-linking component to obtain modified organosilicon microspheres;

[0066] (2) 95 parts of polypropylene and 5 parts of nano-titanium dioxide are co-blended and extruded to obtain an antibacterial base film, 85 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial upper surface film, 95 parts of polypropylene, 0.1 parts of 1,2-benzisothiazolin-3-one and 5 parts of modified silicone microspheres are co-blended and extruded to obtain a reinforced antibacterial lower surface film, the antibacterial base film is fed into a main extruder for melting, the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film are separately put into two auxiliary extruders for melting, extruded through a three-layer structure die, and biaxially stretched to obtain the antibacterial BOPP film.

[0067] The antibacterial BOPP films obtained in Examples 1-3 and the antibacterial BOPP films obtained in Comparative Examples 1-5 were subjected to a tensile property test (GB / T 10003-2008) and an antibacterial test (GB / T 31402-2015). The results are shown in Table 1.

[0068] Table 1 Performance test results

[0069]

[0070] As shown in Table 1, the films obtained in Examples 1-3 have greatly improved antibacterial properties and tensile properties compared to Comparative Examples 1-5. Compared with Example 1, Comparative Example 1 uses a conventional crosslinking agent, which has a certain impact on its antibacterial properties and mechanical properties. The modified silicone microspheres in Comparative Example 2 are not treated with alkali, so that the connection between the microspheres and the crosslinking component is weak. Comparative Example 3 directly uses silicone microspheres without the addition of crosslinking components. The antibacterial agent cannot be evenly and densely dispersed in the system, which affects the antibacterial properties and has a significant impact on the tensile strength. No modified microspheres are added in Comparative Example 4, and the mechanical properties are significantly reduced compared to Comparative Example 3. No antibacterial agent is added to the antibacterial base film in Comparative Example 5, so that the enhanced antibacterial upper surface film and the enhanced antibacterial lower surface film cannot form a passage, which affects its antibacterial properties.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An antibacterial BOPP film, characterized in that: The BOPP film comprises an antibacterial base film, a reinforced antibacterial upper surface film, and a reinforced antibacterial lower surface film, wherein the antibacterial base film is located between the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film; The enhanced antibacterial upper surface film is made of the following raw materials in parts by weight: Polypropylene 80-99 parts, antibacterial agent 0.001-1 parts, modified silicone microspheres 1-20 parts; The enhanced antibacterial lower surface film is made of the following raw materials in parts by weight: Polypropylene 90-99 parts, antibacterial agent 0.001-1 parts, modified silicone microspheres 1-10 parts; The modified organic silicon microspheres for strengthening the antibacterial upper surface film are the same as the modified organic silicon microspheres for strengthening the antibacterial lower surface film; The modified organic silicon microspheres are prepared by a method comprising the following steps: treating the organic silicon microspheres with alkali, and uniformly mixing the treated organic silicon microspheres with a cross-linking component to obtain modified organic silicon microspheres; The alkali treatment step uses a sodium hydroxide solution with a mass concentration of 10-20%, and the alkali treatment time is 0.5-5 hours; the mass ratio of the organic silicon microspheres to the cross-linking component is 1:0.01-1; The cross-linking component is prepared by a method comprising the following steps: Step 1: adding an acrylic acid solution to a sodium hydroxide solution, mixing uniformly to obtain a primary solution, adding an acrylamide solution to the primary solution, mixing uniformly under heating conditions to obtain a secondary solution, and adding an acrylonitrile solution to the secondary solution, mixing uniformly under heating conditions to obtain a tertiary solution; Step 2: adding ammonium persulfate solution and sodium bisulfite solution to the tertiary solution, mixing them evenly under heating conditions to obtain a fourth solution, cooling to room temperature after complete reaction, and dropping sodium hydroxide solution into the fourth solution until the pH value of the solution reaches 7-8, then stopping the dropping, and filtering to obtain a cross-linked component; The antibacterial base film is made of the following raw materials in parts by weight: 90-99 parts of polypropylene, 1-9 parts of nano titanium dioxide, and 0.001-1 part of antibacterial agent.

2. The antibacterial BOPP film according to claim 1, characterized in that: The antibacterial agent of the enhanced antibacterial upper surface film is the same as or different from the antibacterial agent of the enhanced antibacterial lower surface film.

3. The antibacterial BOPP film according to claim 2, characterized in that: The antibacterial agent of the enhanced antibacterial upper surface film is 1,2-benzisothiazolin-3-one; the antibacterial agent of the enhanced antibacterial lower surface film is 1,2-benzisothiazolin-3-one.

4. The antibacterial BOPP film according to claim 1, characterized in that: The concentration of the acrylic acid solution in step 1 is 1-5 g / mL; the concentration of the sodium hydroxide solution in step 1 is 0.01-0.1 g / mL; the concentration of the acrylamide solution in step 1 is 0.1-1 g / mL; the concentration of the acrylonitrile solution in step 1 is 1-5 g / mL; the concentration of the ammonium persulfate solution in step 2 is 0.001-0.01 g / mL; the concentration of the sodium bisulfite solution in step 2 is 0.001-0.01 g / mL; the concentration of the sodium hydroxide solution in step 2 is 0.001-0.01 g / mL.

5. The method for preparing the antibacterial BOPP film according to any one of claims 1 to 4, characterized in that: The steps include: Step 1 is to blend and extrude polypropylene, nano titanium dioxide and an antibacterial agent to obtain an antibacterial base film; Step 2 is to blend and extrude polypropylene, antibacterial agent and modified silicone microspheres to obtain a reinforced antibacterial upper surface film; Step 3 is to blend and extrude polypropylene, antibacterial agent and modified silicone microspheres to obtain a reinforced antibacterial lower surface film; Step 4 is to feed the antibacterial base film into the main extruder for melting, and to place the reinforced antibacterial upper surface film and the reinforced antibacterial lower surface film into two auxiliary extruders for melting, and to extrude through a three-layer structure die head for biaxial stretching to obtain the antibacterial BOPP film.

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