Antibacterial food packaging film and preparation process thereof

Abstract

The present invention relates to the field of food packaging film preparation, and in particular to an antibacterial food packaging film and a preparation process thereof, which is mainly prepared from the following raw materials in parts by weight: 50-60 parts of polyethylene, 5-8 parts of epoxy resin, 2-5 parts of plasticizer, and 3-8 parts of antibacterial agent; the preparation method of the antibacterial agent comprises the following steps: S11: putting silver nitrate powder and gallstone into water together, and mixing them into a pre-reaction material; S12: adding halloysite nanotubes to the pre-reaction material prepared in step S11, preparing a mixed material, subjecting the mixed material to ultrasonic treatment, filtering, and drying. The present application has the advantages of extending the antibacterial time of the prepared packaging film and improving the antibacterial effect of the packaging film.

Description

Technical Field

[0001] The invention relates to the field of food packaging film preparation, in particular to an antibacterial food packaging film and a preparation process thereof. Background Art

[0002] Food safety is closely related to the life and health of each of us. However, during the production and storage of food, food is easily eroded by external air and moisture, causing the massive reproduction of microorganisms and causing food to deteriorate. Therefore, food needs to be packaged to block air and moisture. However, the packaged food will gradually deteriorate during the storage process, resulting in a waste of food resources. Therefore, in order to reduce food waste, food needs to be preserved during the packaging process to extend the shelf life of food. Therefore, higher requirements are also put forward for food packaging films, requiring that the packaging film not only packages and seals the food, but also has a certain antibacterial and bactericidal effect on the packaged food. There are two main methods for preparing packaging films with antibacterial properties in existing production. The first is to directly mix the antibacterial agent with plastic and resin to prepare a plastic masterbatch, and then prepare it by melt extrusion or salivation; the other is to obtain it by coating or vapor deposition of the antibacterial agent on a resin film.

[0003] In the above-mentioned related technologies, the inventors believe that the antibacterial effect of the existing packaging films needs to be extended. Summary of the invention

[0004] In order to prolong the antibacterial time of the prepared packaging film and improve the antibacterial effect of the packaging film, the present application provides an antibacterial food packaging film and a preparation process thereof.

[0005] In the first aspect, the present application provides an antibacterial food packaging film, which adopts the following technical solution:

[0006] An antibacterial food packaging film is mainly made of the following raw materials in parts by weight: 50-60 parts of polyethylene, 5-8 parts of epoxy resin, 2-5 parts of plasticizer, and 3-8 parts of antibacterial agent; the preparation method of the antibacterial agent comprises the following steps:

[0007] S11: putting silver nitrate powder and gallstone into water and mixing them to form a pre-reaction material;

[0008] S12: adding halloysite nanotubes to the pre-reaction material prepared in step S11 to prepare a mixed material, subjecting the mixed material to ultrasonic treatment, filtering, and drying.

[0009] By adopting the above technical scheme, silver nitrate powder has a good antibacterial effect. When used, the silver nitrate powder can release silver ions to pass through the cell wall of bacteria to contact the oxygen metabolic enzyme in the cell, and attract and combine with the negatively charged thiol group in the bacterial cell, so that the bacterial cell cannot breathe, metabolize and reproduce due to protein denaturation, thereby achieving an antibacterial effect; gallstones can pass through the cell wall of bacteria and combine with the protein inside the bacteria, so that the bacterial protein loses activity, thereby killing the bacteria; antibacterial agents are added in the preparation process of the packaging film, and the antibacterial effects of silver nitrate powder and gallstones are better at the beginning, but the antibacterial effects are not long-lasting when used; by using halloysite nanotubes as a carrier, due to the halloysite Nanotubes are substances with different charges on the inner and outer surfaces. The outer surface is a tetrahedral Si-O-Si structure with a negative charge, and the inner surface is a gibbsite octahedral unit with a positive charge, which is conducive to the adsorption and transportation of silver nitrate powder and gallstone by the halloysite nanotubes to form a composite structure; at the same time, through the combination of the halloysite nanotubes with the silver nitrate powder and gallstone, the agglomeration of the silver nitrate powder and gallstone can be reduced, and the antibacterial performance of the silver nitrate powder and gallstone in subsequent use can be improved; because the inner channel of the halloysite nanotube is long and tortuous, the release path of the silver nitrate powder and gallstone can be extended, which plays a sustained release effect on the silver nitrate powder and gallstone, prolongs the timeliness of the antibacterial effect of the silver nitrate powder and gallstone, and improves the long-term antibacterial effect of the prepared packaging film on food.

[0010] Optionally, the mass ratio of the silver nitrate powder to the gallstone in step S11 is (2-3):(3-5).

[0011] By adopting the above technical scheme, since silver nitrate powder is an inorganic antibacterial agent, it is resistant to high temperatures, has low toxicity, a broad antibacterial spectrum, and high safety, but has a high cost and is not suitable for large-scale use; the bactericidal effect of gallstones is weaker than that of silver oxide, but it also has a good antioxidant function during the sterilization process and can prevent food from being oxidized; through the coordinated effect of gallstones and silver nitrate powder, the antibacterial effect of the prepared packaging film on food is jointly improved.

[0012] Optionally, the halloysite nanotubes in step S12 are pretreated before use to obtain pretreated halloysite nanotubes, and the preparation method of the pretreated halloysite nanotubes comprises the following steps:

[0013] 1) mixing the halloysite nanotubes and the urea solution to prepare a mixed solution, and allowing the mixed solution to stand in a vacuum environment for 1-2 hours to prepare a pretreatment solution;

[0014] 2) Add sulfuric acid to the pretreatment solution prepared in step 1), mix well, let stand, filter, and dry to obtain the product.

[0015] By adopting the above technical scheme, the halloysite nanotube has a porous structure, and the pores are interconnected to form a sustained-release channel for silver nitrate powder and gallstone. However, the interior of the halloysite nanotube is easily blocked by impurities. At the same time, due to the narrow pore size of some sustained-release channels, silver nitrate powder and gallstone are easily blocked in the sustained-release channel during the sustained-release process, affecting the sustained-release effect of the halloysite nanotube on silver nitrate powder and gallstone. Sulfuric acid, as a strong acid etchant, can corrode and eliminate impurities in the halloysite nanotube, and can also react with alumina in the halloysite nanotube to produce aluminum ions and sulfur dioxide, expand the pore size of the sustained-release channel, and does not react with the silicon oxide layer in the halloysite nanotube, so that the basic structure of the halloysite nanotube remains intact. By pretreating the halloysite nanotube, the carrying and sustained-release effects of the halloysite nanotube on silver nitrate powder and gallstone are further improved.

[0016] Optionally, the mass ratio of sulfuric acid to halloysite nanotubes in step 2) is (2-5):(23-29).

[0017] By adopting the above technical solution, the mass ratio of sulfuric acid to halloysite nanotubes is adjusted. When the amount of sulfuric acid used is small, the cleaning effect of impurities and pores in the halloysite nanotubes is insufficient, affecting the subsequent loading and sustained release effect of silver nitrate powder and gallstone. However, when the amount of sulfuric acid used is too much, the basic structure of the halloysite nanotubes will be destroyed, so that the loading and sustained release effect of the halloysite nanotubes on silver nitrate powder and gallstone will decrease. Therefore, by adjusting the mass ratio of sulfuric acid to halloysite nanotubes, the prepared antibacterial agent has good long-term bactericidal performance, and the timeliness of the packaging film on food sterilization is improved.

[0018] Optionally, after the pretreatment solution and sulfuric acid are evenly mixed in step 2), the mixture is allowed to stand for 20-40 hours.

[0019] By adopting the above technical scheme, the standing time after the pretreatment solution and sulfuric acid are evenly mixed is adjusted. When the standing time is insufficient, sulfuric acid reacts with the aluminum oxide layer in the halloysite nanotubes, and the generated amorphous silicon dioxide cannot be eliminated in time, and will accumulate inside the halloysite nanotubes, blocking the sustained release channel and affecting the subsequent sustained release effect on silver nitrate powder and gallstone. However, when the standing time is too long, sulfuric acid will destroy the basic structure of the halloysite nanotubes, so that the carrying and sustained release effect of the halloysite nanotubes on silver nitrate powder and gallstone is reduced.

[0020] In a second aspect, the present application provides a process for preparing an antibacterial food packaging film:

[0021] A preparation process of an antibacterial food packaging film mainly comprises the following steps:

[0022] S1: mixing polyethylene, epoxy resin, plasticizer and antimicrobial agent to prepare a premix;

[0023] S2: melt-extrude the premix prepared in step S1, and granulate to obtain a masterbatch;

[0024] S3: Melting the masterbatch prepared in step S2, casting into a film, and drying.

[0025] By adopting the above technical scheme, polyethylene, epoxy resin, plasticizer and antibacterial agent are mixed to prepare masterbatch, so that the antibacterial agent is evenly distributed in the masterbatch, and then the masterbatch is melted and cast into a film, so that the antibacterial agent is evenly distributed in the packaging film, so that when the subsequent packaging film is used to package the food, it has a long-term good antibacterial effect on the food.

[0026] Optionally, the antibacterial agent is immersed in a chitosan solution before use, and then taken out, dried, and crushed.

[0027] By adopting the above technical scheme, chitosan has good antibacterial properties, is non-toxic and has good compatibility with polyethylene, while halloysite nanotubes have poor compatibility with polyethylene and epoxy resin; by impregnating the antibacterial agent in the chitosan solution, chitosan has good moldability, so that the chitosan forms a good protective film and wraps and connects the antibacterial agent through the action of electric charge, so that when the antibacterial agent is subsequently mixed with other raw materials in the bag, the antibacterial agent is not easy to separate from the packaging bag, thereby improving the stability of the antibacterial agent fixed in the packaging bag, thereby making the prepared packaging film have a better and longer-lasting antibacterial effect.

[0028] Optionally, when the antibacterial agent is immersed in the chitosan solution, the chitosan solution is simultaneously subjected to ultrasonic treatment.

[0029] By adopting the above technical solution, when the antibacterial agent is immersed in the chitosan solution, the chitosan solution is ultrasonically treated so that the antibacterial agent can be evenly dispersed in the chitosan solution, so that after subsequent drying and crushing, the chitosan film wrapped on the surface of the antibacterial agent is more uniform.

[0030] Optionally, before the premix is ​​melt-extruded in step S2, a filler is added to the premix; the filler is composed of nano-montmorillonite and bamboo charcoal powder in a mass ratio of (3-5):(2-3).

[0031] By adopting the above technical scheme, nano-montmorillonite and bamboo charcoal powder are added to fill the interior of the packaging film, thereby improving the density and mechanical strength of the prepared packaging film. The nano-montmorillonite has a lamellar structure. During the preparation of the packaging film, chitosan and polyethylene are interspersed in the lamellar structure of the nano-montmorillonite. Through the connecting effect of the nano-montmorillonite, the stability of the antibacterial agent in the packaging film is further improved; at the same time, the bamboo charcoal powder also has a porous structure for bactericidal adsorption, which adsorbs and kills bacteria, thereby further improving the antibacterial effect of the prepared packaging film.

[0032] In summary, this application has the following beneficial effects:

[0033] The present application adds an antibacterial agent to the raw materials for preparing the packaging film. During the preparation process of the antibacterial agent, halloysite nanotubes are used as carriers to load silver nitrate powder and gallstone. The tortuous pore structure inside the halloysite nanotubes has a sustained-release effect on the silver nitrate powder and gallstone, thereby extending the effective time of the antibacterial agent, so that the prepared packaging film has a better and longer-lasting antibacterial effect on food. DETAILED DESCRIPTION

[0034] The present application is further described in detail below with reference to the embodiments and comparative examples;

[0035] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0036] Preparation Example

[0037] Antibacterial agent preparation example 1

[0038] The preparation method of this antibacterial agent preparation example comprises the following steps:

[0039] S11: Take a mixing barrel, put water in the mixing barrel, put silver nitrate powder and gallstone into the water, stir evenly, and prepare a pre-reaction material; the mass ratio of the silver nitrate powder to the gallstone is 2:5;

[0040] S12: adding halloysite nanotubes to the pre-reaction material prepared in step S11, stirring evenly to prepare a mixture, subjecting the mixture to ultrasonic treatment for 10 minutes, filtering, and drying; the mass ratio of the halloysite nanotubes to the silver nitrate powder used is 10:1.

[0041] Antibacterial agent preparation example 2

[0042] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 1 is that the mass ratio of the silver nitrate powder to the gallstone in step S11 is 3:3.

[0043] Antibacterial agent preparation example 3

[0044] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 1 is that the mass ratio of the silver nitrate powder to the gallstone in step S11 is 2.5:4.

[0045] Antibacterial agent preparation example 4

[0046] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 3 is that the halloysite nanotubes used in step S12 are pretreated halloysite nanotubes, and the preparation method of the pretreated halloysite nanotubes used comprises the following steps:

[0047] 1) taking halloysite nanotubes, putting them into a mixing barrel, then adding urea solution into the mixing barrel, mixing them evenly to prepare a mixed solution, and leaving the mixed solution to stand for 1.5 hours under a vacuum environment to prepare a pretreatment solution; the mass ratio of the halloysite nanotubes to the urea solution is 1:4; the mass concentration of urea in the urea solution is 30%;

[0048] 2) Add sulfuric acid solution to the pretreatment solution prepared in step 1), mix well, let stand for 20 hours, filter and dry to obtain; the mass concentration of sulfuric acid in the sulfuric acid solution used is 75%; the mass ratio of sulfuric acid to halloysite nanotubes in the sulfuric acid solution used is 2:29.

[0049] Antibacterial agent preparation example 5

[0050] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 4 is that the halloysite nanotubes used in step S12 are pretreated halloysite nanotubes, and the mass ratio of sulfuric acid to halloysite nanotubes in the sulfuric acid solution used in step 2) of the preparation method of the pretreated halloysite nanotubes is 5:23.

[0051] Antibacterial agent preparation example 6

[0052] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 4 is that the halloysite nanotubes used in step S2 are pretreated halloysite nanotubes, and the mass ratio of sulfuric acid to halloysite nanotubes in the sulfuric acid solution used in step 2) of the preparation method of the pretreated halloysite nanotubes is 3:26.

[0053] Antibacterial agent preparation example 7

[0054] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 6 is that the halloysite nanotubes used in step S2 are pretreated halloysite nanotubes, and the standing time in step 2) of the preparation method of the halloysite nanotubes used is 40 hours.

[0055] Antibacterial agent preparation example 8

[0056] The difference between the preparation method of the antibacterial agent in this preparation example and that in the antibacterial agent preparation example 6 is that the halloysite nanotubes used in step S12 are pretreated halloysite nanotubes, and the standing time in step 2) of the preparation method of the pretreated halloysite nanotubes is 30 hours.

[0057] Example

[0058] Example 1

[0059] In this embodiment, the antibacterial food packaging film is mainly made of the following raw materials by weight: 50 kg polyethylene, 5 kg epoxy resin, 2 kg plasticizer, and 3 kg antibacterial agent; the antibacterial agent used is prepared in Antibacterial Agent Preparation Example 1; the plasticizer used is dioctyl phthalate; the epoxy resin used is bisphenol A epoxy resin;

[0060] The preparation process of the antibacterial food packaging film in this embodiment mainly includes the following steps:

[0061] S1: Take a reaction barrel, put the above-mentioned weight of polyethylene, epoxy resin, plasticizer and antibacterial agent into the reaction barrel and mix them, and after mixing evenly, prepare a premix;

[0062] S2: putting the premix prepared in step S1 into a melt extruder, heating and melting and extruding, and granulating to obtain a masterbatch;

[0063] S3: The masterbatch prepared in step S2 is melted, cast into a film, blown, dried, and rolled up.

[0064] Example 2

[0065] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 1 is that the raw materials for preparing the antibacterial food packaging film of the present application mainly include the following raw materials by weight: 60 kg of polyethylene, 8 kg of epoxy resin, 5 kg of plasticizer, and 8 kg of antibacterial agent; the antibacterial agent used is prepared in Antibacterial Agent Preparation Example 1; the plasticizer used is dioctyl phthalate; and the epoxy resin used is bisphenol A epoxy resin.

[0066] Example 3

[0067] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 1 is that the raw materials for preparing the antibacterial food packaging film of this application mainly include the following raw materials by weight: 55 kg of polyethylene, 6 kg of epoxy resin, 4 kg of plasticizer, and 5 kg of antibacterial agent; the antibacterial agent used is prepared in Antibacterial Agent Preparation Example 1; the plasticizer used is dioctyl phthalate; and the epoxy resin used is bisphenol A epoxy resin.

[0068] Example 4

[0069] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 2.

[0070] Example 5

[0071] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 3.

[0072] Example 6

[0073] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 4.

[0074] Example 7

[0075] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 5.

[0076] Example 8

[0077] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 6.

[0078] Example 9

[0079] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 7.

[0080] Example 10

[0081] The difference between the preparation process of the antibacterial food packaging film in this embodiment and that in Example 3 is that the antibacterial agent used in step S1 is prepared in Antibacterial Agent Preparation Example 8.

[0082] Embodiment 11

[0083] The preparation process of the antibacterial food packaging film in this embodiment is different from that in Example 10 in that the antibacterial agent used is first immersed in a chitosan solution before use, taken out, dried and crushed; the mass concentration of chitosan in the chitosan solution used is 25%; and the solvent of the chitosan solution used is an acetic acid solution with a mass concentration of 3%.

[0084] Example 12

[0085] The preparation process of the antibacterial food packaging film in this embodiment is different from that in Embodiment 11 in that when the antibacterial agent is immersed in the chitosan solution, the chitosan solution is simultaneously subjected to ultrasonic treatment.

[0086] Embodiment 13

[0087] The preparation process of the antibacterial food packaging film in this embodiment is different from that in Example 12 in that before the premix is ​​placed into the melt extruder for melt extrusion in step S2, a filler is added to the premix, and the filler used is composed of nano-montmorillonite and bamboo charcoal powder in a mass ratio of 4:2.5.

[0088] Comparative Example

[0089] Comparative Example 1

[0090] The preparation process of the antibacterial food packaging film in this comparative example is different from that in Example 1 in that the antibacterial agent used is silver nitrate powder.

[0091] Comparative Example 2

[0092] The preparation process of the antibacterial food packaging film in this comparative example is different from that in Example 1 in that the antibacterial agent used is gallstone.

[0093] Comparative Example 3

[0094] The difference between the antibacterial food packaging film in this embodiment and the antibacterial food packaging film in Example 1 is that the raw materials for preparing the antibacterial food packaging film do not contain antibacterial agents.

[0095] Detection Methods

[0096] According to the preparation process of the antibacterial food packaging film in Examples 1-13 and Comparative Examples 1-3, antibacterial food packaging films were prepared as experimental samples. The area of ​​each group of experimental samples was 100 cm 2 According to the test method of QB / T2591-2003, the dilution of Staphylococcus aureus for the test was prepared. The concentration of the dilution of Staphylococcus aureus used was 8*10 5 cfu / ml; add the diluent of Staphylococcus aureus dropwise onto the experimental samples, the volume of the diluent of Staphylococcus aureus used on each experimental sample is 0.2ml, pick up the sterilization cover film with sterilized tweezers and cover each group of experimental samples, and then place the experimental samples in a sterilized plate; place the sterilized plate at 37°C and a relative humidity of 95% for 28 days to obtain the post-experimental samples; determine the total number of viable bacteria on the post-experimental samples according to GB4789.2 "Method for Determination of Total Colony Count in Microbiological Examination of Food Hygiene", determine the number of colonies per square centimeter, and record the data to obtain Table 1:

[0097] The number of colonies per square centimeter = total number of viable bacteria / 100

[0098] Table 1 Antibacterial properties of antibacterial food packaging films prepared in Examples 1-13 and Comparative Examples 1-3

[0099]

[0100] It can be seen from the combination of Examples 1-5, Comparative Examples 1-3 and Table 1 that an antibacterial agent is added to the packaging film, and in the preparation process of the antibacterial agent, silver nitrate powder and gallstone are mixed in a mass ratio of 2.5:4, and then the silver nitrate powder and gallstone are carried by halloysite nanotubes as carriers, and the sustained release effect of the halloysite nanotubes on the silver nitrate powder and gallstone is utilized, so that the silver nitrate powder gradually releases silver ions, which has a bactericidal effect on Staphylococcus aureus, and at the same time, the gallstone has an inactivation effect on the protein of Staphylococcus aureus, so that the prepared antibacterial food packaging film has a good and long-lasting antibacterial effect on Staphylococcus aureus; by comparison with Comparative Examples 1-3, it can be found that the tortuous channels in the halloysite nanotubes have a sustained release effect on the silver nitrate powder and gallstone, which prolongs the antibacterial time of the food packaging film, thereby improving the antibacterial performance of the food packaging film;

[0101] It can be seen from Examples 6-10 and Table 1 that by pretreating the halloysite nanotubes, the impurities in the pores of the halloysite nanotubes are eliminated by using a sulfuric acid solution, and the narrower pores in the pores of the halloysite nanotubes are expanded, while also keeping the basic structure of the halloysite nanotubes intact, so that silver nitrate powder and gallstones can be more smoothly added to the halloysite nanotubes, improving the carrying and sustained-release effects of the halloysite nanotubes on silver nitrate powder and gallstones, thereby improving the antibacterial properties of the prepared antibacterial packaging film; by adjusting the mass ratio of sulfuric acid to halloysite nanotubes in the sulfuric acid solution to 3:26, and controlling the corrosion time of the sulfuric acid solution on the halloysite nanotubes to 30h, the effect of sulfuric acid is avoided to be insufficient, affecting the carrying and sustained-release effects of the halloysite nanotubes on silver nitrate powder and gallstones, while also avoiding the excessive corrosion effect of sulfuric acid, causing damage to the basic structure of the halloysite nanotubes, and also reducing the carrying and sustained-release effects of the halloysite nanotubes on silver nitrate powder and gallstones, thereby affecting the long-term antibacterial effect of the subsequent packaging film.

[0102] It can be seen from Examples 11-13 and Table 1 that by placing the antibacterial agent in a chitosan solution for immersion before use, the antibacterial agent is wrapped by chitosan and its compatibility with other raw materials is improved during the subsequent heating and mixing process, thereby making the antibacterial agent more firmly fixed in the packaging film, and the antibacterial effect of the packaging film is more stable when used; at the same time, by ultrasonically treating the chitosan solution when the antibacterial agent is immersed in the chitosan solution, the antibacterial agent can be evenly dispersed in the chitosan solution, further improving the encapsulation effect of chitosan on the antibacterial agent, so that the encapsulated antibacterial agent can better play a good antibacterial effect in the packaging film;

[0103] By adding nano-montmorillonite and bamboo charcoal powder as fillers in the packaging film, chitosan and polyethylene are connected under the action of the nano-montmorillonite lamellar structure, thereby further improving the stability of the antibacterial agent in the packaging film and also improving the mechanical strength of the packaging film; at the same time, since bamboo charcoal powder also has good bacteria absorption and sterilization effects, it can further improve the killing effect of the packaging film on Staphylococcus aureus while improving the mechanical properties of the packaging film.

[0104] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An antibacterial food packaging film, characterized in that: It is mainly prepared from the following raw materials in parts by weight: 50-60 parts of polyethylene, 5-8 parts of epoxy resin, 2-5 parts of plasticizer, and 3-8 parts of antibacterial agent. The preparation method of the antibacterial agent comprises the following steps: S11: putting silver nitrate powder and gallstone into water and mixing them to form a pre-reaction material; S12: adding halloysite nanotubes to the pre-reaction material prepared in step S11 to prepare a mixed material, subjecting the mixed material to ultrasonic treatment, filtering, and drying; The halloysite nanotubes in step S12 are pretreated before use to obtain pretreated halloysite nanotubes. The preparation method of the pretreated halloysite nanotubes comprises the following steps: 1) mixing the halloysite nanotubes and the urea solution to prepare a mixed solution, and allowing the mixed solution to stand in a vacuum environment for 1-2 hours to prepare a pretreatment solution; 2) adding sulfuric acid to the pretreatment solution prepared in step 1), mixing evenly, standing, filtering, and drying to obtain the product; After the pretreatment solution and sulfuric acid are evenly mixed in step 2), the standing time is 20-40 hours; The plasticizer is dioctyl phthalate, and the epoxy resin is bisphenol A epoxy resin.

2. The antibacterial food packaging film according to claim 1, characterized in that: The mass ratio of the silver nitrate powder to the gallstone in step S11 is (2-3):(3-5).

3. The antibacterial food packaging film according to claim 1, characterized in that: The mass ratio of sulfuric acid to halloysite nanotubes in step 2) is (2-5):(23-29).

4. A process for preparing the antibacterial food packaging film according to claim 1, characterized in that: The main steps are as follows: S1: mixing polyethylene, epoxy resin, plasticizer and antimicrobial agent to prepare a premix; S2: melt-extrude the premix prepared in step S1, and granulate to obtain a masterbatch; S3: Melting the masterbatch prepared in step S2, casting into a film, and drying.

5. The process for preparing the antibacterial food packaging film according to claim 4, characterized in that: Before use, the antibacterial agent is firstly immersed in a chitosan solution, and then taken out, dried and crushed.

6. The process for preparing the antibacterial food packaging film according to claim 5, characterized in that: When the antibacterial agent is immersed in the chitosan solution, the chitosan solution is simultaneously subjected to ultrasonic treatment.

7. The process for preparing the antibacterial food packaging film according to claim 4, characterized in that: Before the premix is ​​melt-extruded in step S2, a filler is added to the premix; the filler is composed of nano-montmorillonite and bamboo charcoal powder in a mass ratio of (3-5):(2-3).

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