Winding film for packaging and preparation method thereof

Abstract

The invention relates to a wrapping film for packaging and a preparation method thereof, and belongs to the technical field of wrapping films, the wrapping film comprises the following raw materials by mass: 70-75 parts of linear low density polyethylene, 7-10 parts of metallocene linear low density polyethylene, 3-5 parts of a polyolefin elastomer, 6-8 parts of polyether ester imide, and 3.7-5.5 parts of aminated mesoporous silica loaded nano-silver. 0.3 to 0.5 part of an antioxidant, 1.5 to 2.5 parts of white oil and 1.5 to 2.5 parts of a silane coupling agent; the preparation method of the aminated mesoporous silica loaded nano-silver comprises the following steps: dispersing mesoporous silica in an ethanol-toluene mixed solvent, adding 3-aminopropyltriethoxysilane, carrying out a stirring reaction at 40-45 DEG C for 4-6 h, carrying out centrifugation and washing, carrying out vacuum drying, placing a dried product in a silver nitrate solution, and controlling the reaction pH to 7-9 and the reaction time to 2-4 h to obtain the aminated mesoporous silica loaded nano-silver. And adding a reducing agent to carry out reduction reaction, centrifuging, washing and drying in vacuum to obtain the aminated mesoporous silica loaded nano-silver. The wrapping film for packaging is good in performance and has an antibacterial effect at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of winding films, and particularly relates to a preparation method of a winding film for packaging. Background Art

[0002] Winding films are mainly applied in the agricultural and industrial fields. The winding films in agriculture are mainly used for the storage of green forage; the winding films in industry are widely used in the fields that need packaging, such as chemical industry, food and beverage, electronic products, and mechanical equipment. By bundling a set of packages with winding films, the goods can be protected from pollution, easily identified and managed, and quickly loaded and unloaded, which plays a protective role for the goods and avoids the phenomenon of loosening or separation in the transportation environment, ensuring the integrity of the packaging.

[0003] Linear low density polyethylene (LLDPE) winding films perform excellently in mechanical properties. Especially, their tensile strength and puncture resistance are higher than those of low density polyethylene, making it the main choice for the raw materials of winding film production. In the early stage, winding films were produced with a single-layer structure of linear low density polyethylene combined with a tackifier (such as polyisobutylene PIB) to improve the film properties. Currently, the mainstream winding films in the market are prepared by a three-layer coextrusion casting process to form a three-layer coextruded structure, with linear low density polyethylene combined with a tackifier as the surface layer, linear low density polyethylene in the middle layer, and low density polyethylene at the bottom layer, thus forming a more stable functional structure.

[0004] In the patent application document of the invention patent application with the application number 202311416358.8 and the invention name of "a preparation method of a tensile-resistant packaging winding film", a preparation method of a tensile-resistant packaging winding film is disclosed, including the following steps: S1. Material preparation: Select LLDPE particle materials, PP particle materials, PIB masterbatch, chlorotrifluoroethylene copolymer particles, and additives for standby; S2. Cleaning and impurity removal: Wash, filter by suction, and vacuum dry the selected LLDPE particle materials, PP particle materials, PIB masterbatch, and chlorotrifluoroethylene copolymer particles respectively; S3. Stirring and mixing: Select the LLDPE particle materials, PP particle materials, PIB masterbatch, and chlorotrifluoroethylene copolymer particles and place them in a mixer for mixing. After heating and stirring evenly, a mixed material is obtained; S4. Winding and extrusion: Feed the plastic melt in the mixer into a twin-screw extruder for high-temperature extrusion; S5. Casting into film: Feed the extruded plastic melt into a casting machine to cast into a film, obtaining a polyethylene winding film; S6. Cooling and calendering: Select the obtained polyethylene winding film, introduce it into a chill roll for cooling and stretching, and then perform calendering treatment on the winding film; S7. Rewinding and packaging: Rewind the produced tensile winding film to form a large master roll and package the master roll. This process improves the tensile strength, tensile fracture resistance, and impact resistance of the winding film, but it does not have antibacterial properties.

[0005] The application number is 202110879612.2, and the invention title is "A Preparation Method of an Antibacterial Plastic Film", which discloses the use of nano-ZnO with a particle size below 30 nm as an antibacterial material for effective antibacterial, and the graft modification of nano-ZnO is used to mix with the polyolefin matrix resin to make the plastic film have antibacterial effects. Although this method can achieve the antibacterial effect on the plastic film, the product performance of the plastic film is poor.

[0006] Therefore, it is very necessary to develop a winding film for packaging with good product performance and antibacterial effects in promoting the development of this industry. Summary of the Invention

[0007] The purpose of the present invention is to provide a winding film for packaging and its preparation method. The winding film for packaging of the present invention has excellent antibacterial properties and mechanical properties.

[0008] The technical solution adopted by the present invention to achieve its purpose:

[0009] A winding film for packaging, by mass, the raw materials include:

[0010] 70-75 parts of linear low-density polyethylene, 7-10 parts of metallocene linear low-density polyethylene, 3-5 parts of polyolefin elastomer, 6-8 parts of polyether ester imide, 3.7-5.5 parts of amino-functionalized mesoporous silica supported silver nanoparticles, 0.3-0.5 parts of antioxidant, 1.5-2.5 parts of white oil, 1.5-2.5 parts of silane coupling agent;

[0011] The preparation method of the amino-functionalized mesoporous silica supported silver nanoparticles is as follows:

[0012] Disperse mesoporous silica in an ethanol-toluene mixed solvent, add 3-aminopropyltriethoxysilane, stir and react at 40-45 °C for 4-6 h, centrifuge, wash and then dry in vacuum. Place the dried product in a silver nitrate solution, control the reaction pH at 7-9, the reaction time is 2-4 h, add a reducing agent for reduction reaction, and after centrifugation, washing and vacuum drying, amino-functionalized mesoporous silica supported silver nanoparticles are obtained.

[0013] Preferably, the pore diameter of the mesoporous silica is 5-10 nm, the specific surface area is 800-1000 m 2 / g; the addition amount of 3-aminopropyltriethoxysilane is 0.1-0.2 times the mass of mesoporous silica; the Ag 2+ concentration in the silver nitrate solution is 0.1-0.3 mM; the reducing agent is sodium citrate or sodium borohydride; the reaction temperature of the reduction reaction is 25-35 °C, the reaction time is 2-4 h; the washing is carried out 3 times with water and 3 times with ethanol; the drying temperature is 70-80 °C, and the drying time is 8-12 h.

[0014] Preferably, the antioxidant includes a phenolic antioxidant and a phosphite antioxidant in a mass ratio of 1:(1.5 - 2).

[0015] Preferably, the silane coupling agent is one of KH-570, KH-550, and KH-560. Here, only these are listed for example, and other silane coupling agents that meet the requirements can also be used.

[0016] A method for preparing a winding film for packaging, comprising the following steps:

[0017] S1. Pretreatment of amino-functionalized mesoporous silica supported silver nanoparticles: Take a part of the silane coupling agent and disperse it in an ethanol aqueous solution, then spray it on the surface of the amino-functionalized mesoporous silica supported silver nanoparticles, and dry for later use.

[0018] S2. Preparation of masterbatch: Take a part of linear low density polyethylene and the amino-functionalized mesoporous silica supported silver nanoparticles treated in step S1, mix them in a high-speed mixer, and then extrude and pelletize at 180 - 200 °C through a screw extruder to obtain masterbatch I.

[0019] Take a part of linear low density polyethylene and polyether ester imide, add a compatibilizer, and extrude and pelletize at 230 - 260 °C to obtain masterbatch II.

[0020] S3. Preparation of film pellets: Add masterbatch I and masterbatch II prepared in step S2, the remaining linear low density polyethylene, metallocene linear low density polyethylene, polyolefin elastomer, antioxidant, white oil, and the remaining silane coupling agent into a high-speed mixer for mixing, and then add them into a screw extruder to extrude and pelletize at 220 - 240 °C, and dry to obtain film pellets.

[0021] S4. Casting into film: Place the film pellets in a casting machine, extrude the melt through a die head, cool to form a film, and wind up to obtain a winding film for packaging.

[0022] Preferably, the dosage ratio of the silane coupling agent in step S1 to that in step S3 is (2 - 3):1.

[0023] Preferably, the dosage ratio of the linear low density polyethylene used for masterbatch I, the linear low density polyethylene used for masterbatch II, and the remaining linear low density polyethylene in step S3 is 1:1.5:1.5.

[0024] Preferably, the temperature of the casting machine in step S4 is controlled as follows: the feeding section is set at 160 - 170 °C, the melting section is set at 200 - 220 °C, the homogenizing section is set at 220 - 230 °C, and the die head is set at 190 - 200 °C.

[0025] Preferably, the rotational speed of the high-speed mixer is 1200 - 1500 rpm, and the mixing time is 5 - 10 min.

[0026] Preferably, after cooling, corona treatment is additionally performed, with a corona power of 8 - 10 kW; the winding speed is 30 - 40 m / min.

[0027] The beneficial effects of the present invention are as follows:

[0028] The present invention uses linear low-density polyethylene as the main matrix, which has good mechanical properties and processability; by adding metallocene linear low-density polyethylene, the comprehensive performance of the winding film can be significantly improved and the processing difficulty can be reduced, while the high transparency of the winding film can be increased; by adding polyolefin elastomer POE (such as ENGAGE TM POE 8150, used in the experiments of the present invention), the impact resistance and flexibility can be improved, especially in cold chain or heavy object packaging, the puncture resistance needs to be enhanced.

[0029] The present invention improves the antioxidant property of the winding film by adding antioxidants to prevent the oxidation of resin polymers in the extruder due to high temperature; the present invention uses a ratio of 1:(1.5 - 2) of phenolic antioxidants and phosphite antioxidants. The phenolic antioxidants capture free radicals to interrupt the oxidation chain reaction, improving the long-term thermal oxygen stability protection of the winding film. The phosphite antioxidants act as a second line of defense, consuming and decomposing hydroperoxides, synergistically improving the antioxidant efficiency with the phenolic antioxidants, and at the same time preventing the oxidation discoloration and thermal degradation of phenolic substances.

[0030] In the present invention, the silane coupling agent is used to enhance the interfacial bonding between the amino-functionalized mesoporous silica-supported silver nanoparticles and the linear low-density polyethylene matrix, preventing nanoparticle aggregation, thereby improving the antibacterial property. The role of the amino-functionalized mesoporous silica-supported silver nanoparticles is on the one hand to provide antibacterial property for the winding film, and on the other hand to act together with polyether ester imide to reduce film adhesion. Polyether ester imide can also improve the heat resistance of the winding film. The role of white oil is to improve the flexibility of the winding film.

[0031] The present invention also provides a preparation method for a winding film for packaging. By separately preparing masterbatches, the mixing and dispersion degree is improved, and by controlling the process conditions, the appearance of sharkskin morphology can be avoided. Detailed Embodiments

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Example 1

[0034] Select SBA-15 mesoporous silica with a pore diameter of 5-10 nm and a specific surface area of 800-1000 m 2 / g as the raw material; prepare a silver nitrate solution with an Ag 2+ concentration of 0.3 mM.

[0035] The preparation method of silver nanoparticles supported on amino-functionalized mesoporous silica is as follows:

[0036] Disperse SBA-15 mesoporous silica in an ethanol-toluene mixed solvent (ethanol:toluene = 3:1), preferably with ultrasonic-assisted dispersion, then add 3-aminopropyltriethoxysilane in an amount of 0.2 times the mass of SBA-15 mesoporous silica, stir and react at 40 °C for 6 h, centrifuge, wash with water 3 times and wash with ethanol 3 times, dry at 70 °C under vacuum for 12 h. Place the dried product in the silver nitrate solution with a pH of 8. During the reaction, the pH can be adjusted by adding a pH regulator (such as ammonia water, citric acid, sodium citrate, etc.). The reaction time is 3 h. Add sodium borohydride in three equal portions for reduction reaction (the molar ratio of sodium borohydride to silver nitrate is 1.5:1). After centrifugation, washing with water 3 times and washing with ethanol 3 times, and drying at 70 °C under vacuum for 12 h, silver nanoparticles supported on amino-functionalized mesoporous silica are obtained for use in the following examples.

[0037] Example 2

[0038] A winding film for packaging, by mass, the raw materials include:

[0039] 70 parts of linear low density polyethylene, 10 parts of metallocene linear low density polyethylene, 5 parts of polyolefin elastomer POE, 8 parts of polyether ester imide, 4 parts of silver nanoparticles supported on amino-functionalized mesoporous silica, 0.1 part of antioxidant 1076, 0.2 part of antioxidant 168, 1.6 parts of white oil, 2 parts of KH-570 silane coupling agent;

[0040] A preparation method of a winding film for packaging, comprising the following steps:

[0041] S1. Pretreatment of silver nanoparticles supported on amino-functionalized mesoporous silica: Take a part of the silane coupling agent and disperse it in an ethanol aqueous solution, then spray it on the surface of silver nanoparticles supported on amino-functionalized mesoporous silica, and dry for later use;

[0042] S2. Prepare masterbatch: Take a part of linear low density polyethylene and silver nanoparticles supported on amino-functionalized mesoporous silica treated in step S1 and mix them in a high-speed mixer at a rotation speed of 1300 rpm for 8 min, and then extrude and pelletize at 200 °C through a screw extruder to obtain masterbatch I;

[0043] Take a part of linear low density polyethylene and polyether ester imide, add a compatibilizer (such as maleic anhydride grafted polyethylene, with a dosage of 10% of the total amount of the part of linear low density polyethylene and polyether ester imide), and extrude and pelletize at 230 °C to obtain masterbatch II;

[0044] S3. Prepare film pellets: Add the masterbatch I and masterbatch II prepared in step S2, the remaining linear low density polyethylene, metallocene linear low density polyethylene, polyolefin elastomer POE, antioxidant, white oil, and the remaining silane coupling agent into a high-speed mixer for mixing at a rotation speed of 1300 rpm for 8 minutes, and then add them into a screw extruder to extrude and pelletize at 220 °C, and dry to obtain film pellets;

[0045] S4. Cast into a film: Place the film pellets in a casting machine, extrude the melt through a die head, and control the temperature of the casting machine as follows: the feeding section is set at 170 °C, the melting section is set at 220 °C, the homogenization section is set at 230 °C, the die head is set at 200 °C, cool to form a film, and then perform corona treatment with a corona power of 9 kW and wind up at a speed of 35 m / min to obtain a winding film for packaging.

[0046] Example 3

[0047] A winding film for packaging, by mass, the raw materials include:

[0048] 75 parts of linear low density polyethylene, 7 parts of metallocene linear low density polyethylene, 3 parts of polyolefin elastomer POE, 6 parts of polyether ester imide, 5 parts of amino-functionalized mesoporous silica supported silver nanoparticles, 0.2 part of antioxidant 1076, 0.3 part of antioxidant 168, 1.5 parts of white oil, 2 parts of KH-570 silane coupling agent;

[0049] A preparation method of a winding film for packaging, comprising the following steps:

[0050] S1. Pretreatment of amino-functionalized mesoporous silica supported silver nanoparticles: Take a part of the silane coupling agent and disperse it in an ethanol aqueous solution, then spray it on the surface of the amino-functionalized mesoporous silica supported silver nanoparticles, and dry for standby;

[0051] S2. Prepare masterbatch: Take a part of linear low density polyethylene and the amino-functionalized mesoporous silica supported silver nanoparticles treated in step S1 and mix them in a high-speed mixer at a rotation speed of 1400 rpm for 7 minutes, and then extrude and pelletize at 200 °C through a screw extruder to obtain masterbatch I;

[0052] Take a part of linear low density polyethylene and polyether ester imide, add a compatibilizer (such as maleic anhydride grafted polyethylene, with a dosage of 10% of the total amount of the part of linear low density polyethylene and polyether ester imide), and extrude and pelletize at 240 °C to obtain masterbatch II;

[0053] S3. Preparation of film pellets: Add the masterbatch I and masterbatch II prepared in step S2, the remaining linear low-density polyethylene, metallocene linear low-density polyethylene, polyolefin elastomer POE, antioxidant, white oil, and the remaining silane coupling agent into a high-speed mixer, mix at a rotation speed of 1400 rpm for 7 minutes, then add them into a screw extruder and extrude and pelletize at 230 °C, and dry to obtain film pellets;

[0054] S4. Casting into film: Place the film pellets in a casting machine, extrude the melt through a die head, and control the temperature of the casting machine as follows: the feeding section is set at 170 °C, the melting section is set at 220 °C, the homogenization section is set at 230 °C, the die head is set at 200 °C, cool to form a film, then perform corona treatment with a corona power of 9 kW, and wind up at a speed of 35 m / min to obtain a winding film for packaging.

[0055] Example 4

[0056] A winding film for packaging, by mass, the raw materials include:

[0057] 72 parts of linear low-density polyethylene, 8 parts of metallocene linear low-density polyethylene, 4 parts of polyolefin elastomer POE, 7 parts of polyether ester imide, 5 parts of amino-functionalized mesoporous silica-supported silver nanoparticles, 0.2 part of antioxidant 1076, 0.3 part of antioxidant 168, 1.5 parts of white oil, and 2 parts of KH-570 silane coupling agent;

[0058] A preparation method of a winding film for packaging, comprising the following steps:

[0059] S1. Pretreatment of amino-functionalized mesoporous silica-supported silver nanoparticles: Take a part of the silane coupling agent and disperse it in an ethanol aqueous solution, then spray it on the surface of the amino-functionalized mesoporous silica-supported silver nanoparticles, and dry for standby;

[0060] S2. Preparation of masterbatch: Take a part of linear low-density polyethylene and the amino-functionalized mesoporous silica-supported silver nanoparticles treated in step S1 and mix them in a high-speed mixer at a rotation speed of 1250 rpm for 9 minutes, then extrude and pelletize at 200 °C through a screw extruder to obtain masterbatch I;

[0061] Take a part of linear low-density polyethylene and polyether ester imide, add a compatibilizer (such as maleic anhydride grafted polyethylene, with a dosage of 10% of the total amount of the part of linear low-density polyethylene and polyether ester imide), and extrude and pelletize at 260 °C to obtain masterbatch II;

[0062] S3. Preparation of film pellets: The masterbatch I and masterbatch II prepared in step S2, the remaining linear low-density polyethylene, metallocene linear low-density polyethylene, polyolefin elastomer POE, antioxidant, white oil, and the remaining silane coupling agent are added to a high-speed mixer and mixed at a rotation speed of 1250 rpm for 9 minutes. Then, they are added to a screw extruder and extruded into pellets at 240 °C, dried to obtain film pellets;

[0063] S4. Casting into film: The film pellets are placed in a casting machine, and the melt is extruded through a die. The temperature of the casting machine is controlled as follows: the feeding section is set at 170 °C, the melting section is set at 220 °C, the homogenizing section is set at 230 °C, the die is set at 200 °C, cooled into a film, and then corona treated with a corona power of 9 kW and wound up at a speed of 35 m / min to obtain a winding film for packaging.

[0064] Comparative Example 1

[0065] The difference from Example 3 is that no polyolefin elastomer is added.

[0066] Comparative Example 2

[0067] The difference from Example 3 is that no silver nanoparticles supported on amino-functionalized mesoporous silica are added.

[0068] Performance testing

[0069] The mechanical properties are tested according to the standard BB / T0024-2018;

[0070] The antibacterial property is tested by the film sticking method for the inhibitory activity against Escherichia coli and Staphylococcus aureus according to the national standard GB / T21510-2008;

[0071] The performance test results are shown in Tables 1-5.

[0072] Table 1

[0073]

[0074] Table 2

[0075]

[0076] Table 3

[0077]

[0078]

[0079] Table 4

[0080]

[0081] Table 5

[0082]

[0083]

[0084] According to the above performance tests, the winding film for packaging of the present invention has excellent mechanical properties, excellent antibacterial properties, and high light transmittance. The absence of polyolefin elastomer will result in a decrease in the permanent deformation effect and at the same time reduce the puncture resistance; the absence of amino-functionalized mesoporous silica supported silver nanoparticles will significantly reduce the antibacterial effect and also have a slight impact on the viscosity.

[0085] Further research and development in this field can also add light stabilizers (such as hindered amine light stabilizers, HALS) on the basis of the present invention to synergistically improve the weather resistance for better adaptation to outdoor packaging scenarios.

[0086] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present invention, which are used to illustrate the technical solutions of the present invention rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments or easily conceive of changes, or perform equivalent replacements for some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention.

Claims

1. A stretch film for packaging, characterized in that: By mass parts, the raw materials include: 70 - 75 parts of linear low density polyethylene, 7 - 10 parts of metallocene linear low density polyethylene, 3 - 5 parts of polyolefin elastomer, 6 - 8 parts of polyether ester imide, 3.7 - 5.5 parts of amino-functionalized mesoporous silica supported silver nanoparticles, 0.3 - 0.5 parts of antioxidant, 1.5 - 2.5 parts of white oil, 1.5 - 2.5 parts of silane coupling agent; The preparation method of the amino-functionalized mesoporous silica supported silver nanoparticles is as follows: Disperse mesoporous silica in an ethanol-toluene mixed solvent, add 3-aminopropyltriethoxysilane, stir and react at 40 - 45 °C for 4 - 6 h, centrifuge, wash and then dry in vacuum. Place the dried product in a silver nitrate solution, control the reaction pH at 7 - 9, react for 2 - 4 h, add a reducing agent for reduction reaction, and after centrifugation, washing and vacuum drying, obtain the amino-functionalized mesoporous silica supported silver nanoparticles.

2. A winding film for packaging according to claim 1, wherein The pore diameter of the mesoporous silica is 5-10 nm, and the specific surface area is 800-1000 m 2 / g; the addition amount of 3-aminopropyltriethoxysilane is 0.1-0.2 times the mass of the mesoporous silica; the Ag 2+ concentration in the silver nitrate solution is 0.1-0.3 mM; the reducing agent is sodium citrate or sodium borohydride; the reaction temperature of the reduction reaction is 25-35 °C, and the reaction time is 2-4 h; the washing is carried out by water washing at least 3 times, ethanol washing at least 3 times, or water washing and ethanol washing alternately; the drying temperature is 70-80 °C, and the drying time is 8-12 h.

3. A winding film for packaging according to claim 1, wherein The antioxidant includes a phenolic antioxidant and a phosphite antioxidant with a mass ratio of 1:(1.5 - 2).

4. The packaging stretch film according to claim 1, characterized in that: The silane coupling agent is one of KH-570, KH-550, and KH-560.

5. A preparation method of a winding film for packaging, characterized in that, It includes the following steps: S1. Pretreatment of amino-functionalized mesoporous silica supported silver nanoparticles: Take a part of the silane coupling agent and disperse it in an ethanol aqueous solution, then spray it on the surface of the amino-functionalized mesoporous silica supported silver nanoparticles, and dry for standby; S2. Preparation of masterbatch: Take a part of the linear low density polyethylene and the amino-functionalized mesoporous silica supported silver nanoparticles treated in step S1 and mix them in a high-speed mixer, then extrude and pelletize at 180 - 200 °C through a screw extruder to obtain masterbatch I; Take a part of the linear low density polyethylene and polyether ester imide, add a compatibilizer, and extrude and pelletize at 220 - 240 °C to obtain masterbatch II; S3. Preparation of film pellets: Add the masterbatch I and masterbatch II prepared in step S2, the remaining linear low density polyethylene, metallocene linear low density polyethylene, polyolefin elastomer, antioxidant, white oil, and the remaining silane coupling agent into a high-speed mixer for mixing, then add them into a screw extruder and extrude and pelletize at 230 - 260 °C, and dry to obtain film pellets; S4. Cast film formation: Place the film pellets in a casting machine, extrude the melt through a die head, cool to form a film, and wind up to obtain a winding film for packaging.

6. The preparation method of a winding film for packaging according to claim 5, wherein The dosage ratio of the silane coupling agent in step S1 to that in step S3 is (2 - 3):

1.

7. The preparation method of a winding film for packaging according to claim 5, characterized in that, The dosage ratio of the linear low density polyethylene used for masterbatch I, the linear low density polyethylene used for masterbatch II, and the remaining linear low density polyethylene in step S3 is 1:1.5:1.

5.

8. The preparation method of a winding film for packaging according to claim 5, characterized in that, The temperature of the casting machine in step S4 is controlled as follows: the feeding section is set at 160 - 170 °C, the melting section is set at 200 - 220 °C, the homogenization section is set at 220 - 230 °C, and the die head is set at 190 - 200 °C.

9. The preparation method of a winding film for packaging according to claim 5, characterized in that, The rotation speed of the high-speed mixer is 1200 - 1500 rpm, and the mixing time is 5 - 10 min.

10. The preparation method of a winding film for packaging according to claim 5, wherein, After cooling, corona treatment is additionally carried out, with a corona power of 8 - 10 kW; the winding speed is 30 - 40 m / min.

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