Degradable high-barrier antibacterial film

Abstract

The application relates to a degradable high-barrier antibacterial film which is composed of three layers of films, including a PVA film as a bottom layer, a silicon oxide film layer as a middle layer and a chitosan modified crosslinked film layer as an outer layer, the three layers are combined through different processes, the combined film has good mechanical properties, the tensile strength and tear strength can reach 54.7 MPa and 204.6 N, has good oxygen barrier property, the oxygen passing rate of a 0.43 mm thick film is only 27.9 cm 3 / (m 3 ·24 hr·MPa), and the film can be applied to the packaging field of food, medicines and the like.

Description

TECHNICAL FIELD

[0001] The application relates to a film preparation method, in particular to a film preparation method with degradability, high strength, high oxygen barrier property and antibacterial property. BACKGROUND

[0002] Although plastic materials have excellent performance and wide applicability, due to the fact that the plastic materials cannot be degraded, in the face of increasingly serious resource crisis and environmental pollution, searching for a substitute material with excellent performance and renewability has become the top priority in the field of materials.

[0003] In the field of food and drug packaging, the film material has high requirements, for example, in addition to guaranteeing the mechanical properties, the film also needs to have special functions, for example, due to the requirement of quality preservation, the film needs to have good oxygen barrier property, and for some packaging materials directly contacting food, the film preferably also has certain antibacterial property. It is very difficult to realize the above characteristics while guaranteeing the degradability. For example, the film prepared by directly using a degradable material often cannot realize good barrier property due to the structural characteristics, for example, polylactic acid film, polylactic acid / PBAT film and PVA film cannot realize the oxygen transmission rate and carbon dioxide barrier property required by the demand. And the realization of antibacterial property often also needs to add functional substances such as antibacterial components, which also affects the mechanical properties and barrier property of the material.

[0004] In view of the above problems, the patent aims to develop a degradable film material with good gas barrier property, and realize balanced comprehensive performance through the functions of different functional layers by means of special multilayer compounding. SUMMARY

[0005] The application aims to overcome the defects of degradable material barrier property and antibacterial property, and develop a film material with good mechanical property, gas barrier property and antibacterial property.

[0006] The application is realized by the following technical scheme:

[0007] A degradable high-barrier antibacterial film is composed of three layers of films, including a PVA film as a bottom layer, a silicon oxide film layer as a middle layer and a modified chitosan cross-linked film layer as an outer layer. The PVA film is obtained by casting, the silicon oxide film layer is obtained by vacuum sputtering on the surface of the PVA film after plasma treatment, and the modified chitosan cross-linked film layer is obtained by casting on the surface of the silicon film layer. The three layers of films are further post-treated by low-pressure heat treatment to realize the tight combination between the whole.

[0008] Further, the thickness of the PVA film is between 0.1-0.3mm, the thickness of the silicon oxide film layer is between 0.05-0.1mm, and the thickness of the modified chitosan cross-linked film layer is between 0.1-0.2mm.

[0009] Further, the PVA film layer is prepared by using PVA as raw material, nanocellulose as reinforcing agent, and glutaraldehyde as crosslinking agent, and then casting into film after dissolving in water; the processing technology is as follows: PVA is added into pure water at 60-90℃, and stirred at high speed to dissolve uniformly to form a solution with mass concentration of 10-25%, then nanocellulose with mass of 1-3% of PVA and glutaraldehyde with mass of 1-3% of PVA are added, and the solution is stirred quickly and uniformly, then casting is performed, the initial casting temperature is 30-45℃, the temperature is maintained for 2-4min, after preliminary film formation, heating is performed to 60-80℃, and the temperature is maintained for 1-2min, then natural cooling is performed to room temperature, and the film product is obtained.

[0010] Further, the nanocellulose has a diameter of 10-50nm and an aspect ratio of 10:100.

[0011] Further, the PVA is one of 1788, 2488, 1799, 2099, 2299, and 2499.

[0012] Further, the silicon oxide film layer is formed by plasma treatment on the surface of the PVA film layer and then vacuum sputtering.

[0013] Further, the process for preparing the modified chitosan crosslinking film layer is as follows: modified chitosan and water-soluble silane coupling agent are dissolved in weak acid aqueous solution with a volume concentration of 1-3%, the mass concentration of the modified chitosan is 4-6%, the mass concentration of the water-soluble silane coupling agent is 2-3%, then a multi-armed aldehyde-based macromolecule with a mass of 2-4% of the modified chitosan is added, and the solution is stirred uniformly after being heated to 40-60℃, then casting is performed on the surface of the silicon oxide film layer, during the casting process, a weak alkali solution of NaOH with a mass concentration of 2-4% is sprayed on the surface of the film in the form of spray, the pH value of the casting solution is adjusted to 7.5-8, and the temperature is maintained at 50-60℃ for 5-8min to achieve complete drying.

[0014] Further, the modified chitosan is N-acylated chitosan derivative and quaternary ammonium salt chitosan, the modified chitosan is water-soluble, and the modification degree is 3-12% of the mass of chitosan.

[0015] Further, the N-acylated chitosan derivative can be one of N-succinyl chitosan, N-methyl acryloyl chitosan, and N-maleoyl chitosan.

[0016] Further, the water-soluble silane coupling agent includes vinyltriethoxysilane and 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, and a commercially available water dispersion silane coupling agent such as Wanjing Dynasylan F 8815 silane coupling agent can also be used.

[0017] Further, the multi-arm aldehyde-based macromolecule is one of a four-arm polyethylene glycol aldehyde group, a six-arm polyethylene glycol aldehyde group, and an eight-arm polyethylene glycol aldehyde group, and the molecular weight is between 2000 and 6000.

[0018] Further, after the three-layer film is cast into a film by the modified chitosan cross-linked film layer, the three layers are further tightly combined by rolling at a temperature of 60-80 DEG C for 1-2 min.

[0019] Further, the beneficial effects of the present application are that, in view of the deficiencies of the prior art, a three-layer composite method is adopted, the PVA layer ensures the mechanical strength, the surface silicon plating film layer realizes oxygen barrier property, and the outer modified chitosan layer not only ensures that the silicon plating film layer will not be damaged by stress and friction, but also further strengthens the gas barrier property; at the same time, in order to ensure the stable and tight combination between the film layers, a silicon coupling agent is added to the modified chitosan layer to strengthen the connection between the silicon layer and the silicon layer, and the macromolecular cross-linking further strengthens the mechanical properties of the film, and the hot pressing process after casting further strengthens the stable combination between the three layers of the film. In terms of function, the modified chitosan layer has antibacterial property, and the modified chitosan layer and the PVA layer both have degradability, which also ensures the overall degradability of the film.

[0020] Further, the film of the present application is tested in the following manner:

[0021] The tensile strength and elongation at break of the film are tested according to the standard GB / T 1040.3-2006;

[0022] The tear strength of the film is tested according to the standard GB / T 16578.3-2008;

[0023] The impact strength of the film is tested according to the standard GB / T 9639.1-2008;

[0024] The puncture resistance of the film is tested according to the standard GB / T 37841-2019;

[0025] The oxygen barrier property of the film is tested according to the standard GB / T 18454-2019;

[0026] The antibacterial property of the film is tested by placing 10*8 CFU / mL of Staphylococcus aureus as a target on the surface of the film, and observing the killing rate of the bacteria within seven days as the evaluation standard. DETAILED DESCRIPTION

[0027] The exemplary implementation methods of the present application will be described in detail below. However, these implementation methods are only for exemplary purposes, and the present application is not limited thereto. EMBODIMENT

[0028] The application discloses a degradable high-barrier antibacterial film which is composed of three layers of films, including a PVA film as a bottom layer, a silicon oxide film layer as a middle layer and a modified chitosan cross-linked film layer as an outer layer, wherein the PVA film is obtained by casting, the silicon oxide film layer is obtained by vacuum sputtering on the surface of the PVA film after plasma treatment, and the modified chitosan cross-linked film layer is obtained by casting on the surface of the silicon film layer, and the three layers of films are further post-treated by low-pressure heat treatment to realize the close combination of the whole.

[0029] The thickness of the PVA film is 0.2 mm, the thickness of the silicon oxide film layer is 0.08 mm, and the thickness of the modified chitosan cross-linked film layer is 0.15 mm.

[0030] The PVA film layer is prepared by casting after dissolving PVA1788 as a raw material, nanocellulose as a reinforcing agent and glutaraldehyde as a cross-linking agent in water; the processing technology is as follows: PVA1788 is dissolved in pure water at 65 DEG C to prepare a solution with a mass concentration of 12%, then nanocellulose with a mass of 1.5% of PVA and glutaraldehyde with a mass of 2% of PVA are added, and the mixture is uniformly stirred and then casted, the initial casting temperature is 40 DEG C, the temperature is kept for 2.5 min, then the film is heated to 70 DEG C and kept for 1.5 min, and then the film is naturally cooled to room temperature to obtain the film product.

[0031] The nanocellulose has a diameter of 20-40 nm and a length-diameter ratio of 10:100.

[0032] The processing technology of the modified chitosan cross-linked film layer is as follows: N-succinyl chitosan and 3-(2,3-epoxypropoxy) propyl methyldiethoxysilane are dissolved in a 2.5% hydrochloric acid aqueous solution, the mass concentration of N-succinyl chitosan is 5%, the mass concentration of 3-(2,3-epoxypropoxy) propyl methyldiethoxysilane is 2.5%, then four-arm polyethylene glycol aldehyde groups with a mass of 3% of N-succinyl chitosan are added, the mixture is uniformly stirred after being heated to 50 DEG C, and then the mixture is casted on the surface of the silicon oxide film layer, during the casting process, a 3.5% NaOH weak alkali solution is sprayed on the surface of the film in a spraying form, the pH value is adjusted to 7.5, and the mixture is kept at 55 DEG C for 6 min to realize complete drying.

[0033] The modification degree of the N-acylated chitosan is 5.5% of the mass of chitosan.

[0034] The silicon oxide film layer is formed by vacuum sputtering on the surface of the PVA film layer after plasma treatment.

[0035] The molecular weight of the multi-four-arm polyethylene glycol aldehyde groups is 3200.

[0036] The three-layer film is further tightly combined by rolling at a temperature of 70℃ for 1.5 min after the modified chitosan cross-linked film layer is casted.

[0037] The performance of the prepared film material is shown in Table 1.

[0038] Example 2

[0039] A degradable high-barrier antibacterial film is composed of three layers, including a PVA film as the bottom layer, a silicon oxide film layer as the middle layer, and a modified chitosan cross-linked film layer as the outer layer. The PVA film is obtained by casting, the silicon oxide film layer is obtained by vacuum sputtering on the surface of the plasma-treated PVA film, and the modified chitosan cross-linked film layer is obtained by casting on the surface of the silicon film layer. The three-layer film is further post-treated by low-pressure heat treatment to achieve tight combination between the whole.

[0040] The thickness of the PVA film is 0.15 mm, the thickness of the silicon oxide film layer is 0.06 mm, and the thickness of the modified chitosan cross-linked film layer is 0.18 mm.

[0041] The PVA film layer is prepared by casting after dissolving PVA 2488 as the raw material, nanocellulose as the reinforcing agent, and glutaraldehyde as the cross-linking agent in water. The processing technology is as follows: PVA is dissolved in pure water at 70℃ to prepare a solution with a mass concentration of 15%, then nanocellulose with a mass of 2% of PVA and glutaraldehyde with a mass of 1.5% of PVA are added, and the solution is stirred uniformly, then casting is performed, the initial casting temperature is 42℃, the temperature is maintained for 3.5 min, then the film is heated to 75℃ and maintained for 1.5 min, and then naturally cooled to room temperature to obtain the film product.

[0042] The nanocellulose has a diameter of 10-50 nm and an aspect ratio of 10:80.

[0043] The process of the modified chitosan cross-linked film layer is as follows: quaternary ammonium salt chitosan and Dynasylan F 8815 silane coupling agent are dissolved in a 2.0% hydrochloric acid aqueous solution, the mass concentration of quaternary ammonium salt chitosan is 5.5%, and the mass concentration of Dynasylan F 8815 silane coupling agent is 2.8%, then 3.5% of six-armed polyethylene glycol aldehyde groups are added to the quaternary ammonium salt chitosan, the solution is stirred uniformly after being heated to 55℃, then casting is performed on the surface of the silicon oxide film layer, a 2.5% NaOH weak base solution is sprayed on the surface of the film in the form of a mist during the casting process, the pH value is adjusted to 7.8, and the film is completely dried at 58℃ for 7 min.

[0044] The modification degree of the quaternary ammonium salt chitosan is 8.5% of the mass of chitosan.

[0045] The forming of the silicon oxide film layer is vacuum sputtering after plasma treatment of the surface of the PVA film layer.

[0046] The molecular weight of the six-arm polyethylene glycol aldehyde group is 4800.

[0047] The three-layer film is further tightly combined between the layers by rolling at a temperature of 75℃ for 2min after casting and film forming of the modified chitosan cross-linked film layer.

[0048] The performance of the prepared film material is shown in Table 1.

[0049] Example 3

[0050] A degradable high-barrier antibacterial film is composed of three-layer film, including a PVA film as the bottom layer, a silicon oxide film layer as the middle layer, and a modified chitosan cross-linked film layer as the outer layer, wherein the PVA film is obtained by casting, the silicon oxide film layer is obtained by vacuum sputtering after plasma treatment of the surface of the PVA film, and the modified chitosan cross-linked film layer is obtained by casting on the surface of the silicon film layer, and the three-layer film is further post-treated by low-pressure heat treatment to realize tight combination between the whole.

[0051] The thickness of the PVA film is 0.25mm, the thickness of the silicon oxide film layer is 0.06mm, and the thickness of the modified chitosan cross-linked film layer is 0.12mm.

[0052] The PVA film layer is obtained by casting after dissolving PVA in water with nanocellulose as a reinforcing agent and glutaraldehyde as a cross-linking agent; the processing technology is as follows: PVA1799 is dissolved in pure water at 70℃ to prepare a solution with a mass concentration of 22%, nanocellulose with a mass of 2% of PVA and glutaraldehyde with a mass of 2.4% of PVA are added after uniform stirring, and then casting is performed after rapid stirring, the initial casting temperature is 36℃, the temperature maintaining time is 2.4min, the film is heated to 80℃ after film forming, and the temperature is maintained for 1.5min, and then the film product is obtained after natural cooling to room temperature.

[0053] The diameter of the nanocellulose is between 20-50nm, and the aspect ratio is between 10:100.

[0054] The process of the modified chitosan cross-linked membrane layer is as follows: N-methyl acryl chitosan and vinyl triethoxysilane are dissolved in a 2.2% volume concentration hydrochloric acid aqueous solution, the mass concentration of the N-methyl acryl chitosan is 6%, the mass concentration of the vinyl triethoxysilane is 2.8%, then 3.8% of the mass of the N-methyl acryl chitosan of four-arm polyethylene glycol aldehyde is added, the mixture is stirred uniformly after being heated to 56℃, and the surface of the silicon oxide membrane layer is cast, during the casting process, a 3.5% mass concentration NaOH weak base solution is sprayed on the surface of the membrane in the form of a spray, the pH value is adjusted to 8, and the mixture is kept at 52℃ for 6 min to achieve complete drying.

[0055] The modification degree of the N-methyl acryl chitosan is 4.2% of the mass of the chitosan.

[0056] The silicon oxide membrane layer is formed by plasma treatment of the surface of a PVA membrane and then vacuum sputtering.

[0057] The molecular weight of the four-arm polyethylene glycol aldehyde is 5000.

[0058] The three-layer membrane is further tightly combined by rolling at a temperature of 80℃ for 1.2 min after the modified chitosan cross-linked membrane layer is cast.

[0059] The performance of the prepared membrane material is shown in Table 1.

[0060] Example 4

[0061] A degradable high-barrier antibacterial membrane is composed of three layers of membranes, including a PVA membrane as a bottom layer, a silicon oxide membrane layer as a middle layer, and a modified chitosan cross-linked membrane layer as an outer layer, wherein the PVA membrane is obtained by casting, the silicon oxide membrane layer is obtained by vacuum sputtering on the surface of a PVA membrane treated by plasma, and the modified chitosan cross-linked membrane layer is obtained by casting on the surface of the silicon-coated membrane layer, and the three-layer membrane is further post-treated by low-pressure heat treatment to achieve tight combination between the whole.

[0062] The thickness of the PVA membrane is 0.12 mm, the thickness of the silicon oxide membrane layer is 0.09 mm, and the thickness of the chitosan cross-linked membrane layer is 0.18 mm.

[0063] The PVA film layer is prepared by using PVA2099 as raw material, nanocellulose as reinforcing agent, and glutaraldehyde as crosslinking agent, and then casting into film after dissolving in water; the processing technology is as follows: PVA is dissolved in pure water at 80℃ to prepare a solution with a mass concentration of 14%, after uniform stirring and dissolution, nanocellulose with a mass of 1.6% of PVA and glutaraldehyde with a mass of 2.8% of PVA are added, and then fast stirring is performed, the initial casting temperature is 42℃, the temperature is maintained for 3.2 min, after film formation, heating to 65℃ is performed, and the temperature is maintained for 2 min, and then natural cooling to room temperature is performed to obtain the film product.

[0064] The diameter of the nanocellulose is between 10-40 nm, and the aspect ratio is between 20:80.

[0065] The process of the modified chitosan crosslinked film layer is as follows: N-maleoyl chitosan and 3-(2,3-epoxypropoxy) propyl methyldiethoxysilane are dissolved in a hydrochloric acid aqueous solution with a volume concentration of 2.8%, the mass concentration of N-maleoyl chitosan is 4.8%, and the mass concentration of 3-(2,3-epoxypropoxy) propyl methyldiethoxysilane is 2.6%, then four-arm polyethylene glycol aldehyde groups with a mass of 2.6% of N-maleoyl chitosan are added, after heating to 48℃ and uniform stirring, casting is performed on the surface of the silicon oxide film layer, during the casting process, a weak alkali solution of NaOH with a mass concentration of 3.2% is sprayed on the surface of the film in the form of spray, the pH value is adjusted to 7.8, and the temperature is maintained at 45℃ for 6.5 min to achieve complete drying.

[0066] The modification degree of the N-maleoyl chitosan is 7.5% of the mass of chitosan.

[0067] The silicon oxide film layer is formed by plasma treatment of the surface of the PVA film layer and then vacuum sputtering.

[0068] The molecular weight of the four-arm polyethylene glycol aldehyde group is 4800.

[0069] After the modified chitosan crosslinked film layer is cast and formed into a film, rolling is performed at a temperature of 70℃ for 2 min to achieve further close combination between the multiple layers.

[0070] The performance of the prepared film material is shown in Table 1.

[0071] Comparative Example 1

[0072] All the formulations and Example 1 are consistent, and the thickness of the three-layer film is controlled by the casting and vacuum sputtering process;

[0073] The thickness of the PVA film is 0.15 mm, the thickness of the silicon oxide film layer is 0.1 mm, and the thickness of the modified chitosan crosslinked film layer is 0.15 mm.

[0074] The performance of the prepared film is shown in Table 1.

[0075] Compared with Example 1, the decrease of the thickness of the PVA film leads to a certain degree of decrease of the strength, but the increase of the thickness of the silicon oxide film layer leads to further improvement of the oxygen barrier property.

[0076] Comparative Example 2

[0077] Compared with Example 1, no additional cross-linking layer of the cast modified chitosan is added outside the silicon oxide film layer; due to slight process errors, the thickness of the PVA film is 0.22 mm, and the thickness of the silicon oxide film layer is 0.09 mm.

[0078] The performance is shown in Table 1.

[0079] Compared with Example 1, due to the absence of the surface modified chitosan cross-linking layer, the barrier property is decreased to a certain degree, the antibacterial property is completely lost, and in the mechanical property, the strength of the film is decreased to a certain degree, but the tear resistance is almost unchanged.

[0080] Comparative Example 3

[0081] Compared with Example 1, no nanocellulose is added in the PVA film layer; glutaraldehyde is used to replace the four-arm polyethylene glycol aldehyde group in the modified chitosan cross-linking layer, and the thickness of the PVA film is 0.14 mm, the thickness of the silicon oxide film layer is 0.1 mm, and the thickness of the modified chitosan cross-linking film layer is 0.14 mm.

[0082] The performance is shown in Table 1.

[0083] Compared with Example 1, due to the absence of the reinforcing material in the two layers, the strength of the film is significantly decreased, and the barrier property is also decreased to a certain degree.

[0084] Comparative Example 4

[0085] Compared with Example 1, in the preparation of the modified chitosan cross-linking layer, 3-(2,3-epoxypropoxy) propyl methyldiethoxysilane is not added, and other processes are completely consistent, the thickness of the prepared PVA film is 0.21 mm, the thickness of the silicon oxide film layer 2 is 0.09 mm, and the thickness of the modified chitosan cross-linking film layer 3 is 0.14 mm.

[0086] The performance is shown in Table 1.

[0087] Compared with Example 1, due to the absence of the material having strong interaction with the silicon oxide film in the chitosan film layer, the modified chitosan film layer is more likely to separate from the main film. At the same time, the oxygen barrier property is decreased.

[0088] Comparative Example 5

[0089] The thickness of the PVA film was 0.2 mm and the thickness of the modified chitosan crosslinked film layer was 0.15 mm, without adding a silicon oxide film layer by vacuum sputtering, compared with Example 1.

[0090] The properties are shown in Table 1.

[0091] The oxygen barrier property was significantly decreased and the strength was decreased to some extent, compared with Example 1, since the silicon oxide film layer was not added.

[0092] Table 1. Properties of film materials prepared in Examples and Comparative Examples

[0093] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tensile strength (MPa) 54.7 48.1 52.6 55.9 32.6 40.5 24.9 47.2 46.5 Elongation at break (%) 137.4 124.6 105.3 132.8 146.4 103.5 47.2 82.5 132.7 Tear strength (machine direction) / (transverse direction) (MPa) 204.6 / 182.4 185.8 / 137.6 167.5 / 109.5 196.3 / 147.8 82.3 / 74.6 201.3 / 171.5 64.2 / 22.4 147.3 / 88.3 165.4 / 146.9 oxygen transmission rate cm 3 (m 3 ·24 hr·MPa)]]> 32.4 41.4 43.6 27.9 24.6 54.7 62.3 127.6 2038.5 Antibacterial property 100% 100% 100% 100% 100% 0% 0% 100% 100% Surface friction 100 times Not separated Not separated Not separated Not separated Not separated Not separated Not separated Separated Not separated

Claims

1. A degradable high-barrier antibacterial film, which is composed of three layers of film, including a PVA film layer as a bottom layer, a silicon oxide film layer as a middle layer, and a modified chitosan cross-linked film layer as an outer layer, wherein the PVA film layer is obtained by casting, the silicon oxide film layer is obtained by vacuum sputtering on the surface of the PVA film layer after plasma treatment, and the modified chitosan cross-linked film layer is obtained by casting on the surface of the silicon oxide film layer, and the three layers of film are further post-treated by low-pressure heat treatment to achieve tight combination among the whole. Characterized in that: the PVA film layer is prepared by casting a solution of PVA as raw material, nanocellulose as reinforcing agent, and glutaraldehyde as cross-linking agent dissolved in water; the processing technology is as follows: PVA is added to pure water at 60-90℃, and stirred at high speed to dissolve uniformly to prepare a solution with a mass concentration of 10-25%, then nanocellulose with a mass of 1-3% of PVA and glutaraldehyde with a mass of 1-3% of PVA are added, and the solution is stirred quickly and uniformly before casting, the initial casting temperature is 30-45℃, the temperature is maintained for 2-4 min, after the preliminary film formation, the temperature is raised to 60-80℃, and the temperature is maintained for 1-2 min, and then the film product is obtained by natural cooling to room temperature; the preparation process of the modified chitosan cross-linked film layer is as follows: modified chitosan and water-soluble silane coupling agent are dissolved in a weak acid aqueous solution with a volume concentration of 1-3%, the mass concentration of modified chitosan is between 4-6%, the mass concentration of water-soluble silane coupling agent is between 2-3%, and a multi-armed aldehyde-based macromolecule with a mass of 2-4% of modified chitosan is further added, the solution is stirred uniformly after being heated to 40-60℃, and then casting is performed on the surface of the silicon oxide film layer, during the casting process, a weak alkali solution of NaOH with a mass concentration of 2-4% is sprayed on the surface of the film in the form of spray, the pH value of the casting solution is adjusted to 7.5-8, and the complete drying is achieved at 50-60℃ for 5-8 min.

2. The degradable high barrier antibacterial film according to claim 1, wherein, the thickness of the PVA film layer is between 0.1-0.3 mm, the thickness of the silicon oxide film layer is between 0.05-0.1 mm, and the thickness of the modified chitosan cross-linked film layer is between 0.1-0.2 mm.

3. The degradable high barrier antibacterial film according to claim 1, wherein, the multi-armed aldehyde-based macromolecule is one of four-armed polyethylene glycol aldehyde, six-armed polyethylene glycol aldehyde, and eight-armed polyethylene glycol aldehyde, and the molecular weight is between 2000-6000.

4. The degradable high barrier antibacterial film according to claim 1, wherein, the modified chitosan is N-acylated chitosan derivative and quaternary ammonium salt chitosan, the modified chitosan is water-soluble, and the modification degree is between 3-12% of the mass of chitosan.

5. The degradable high barrier antibacterial film according to claim 1, wherein, the water-soluble silane coupling agent includes vinyltriethoxysilane, 3-(2,3-epoxypropoxy) propylmethyldiethoxysilane, or Wanheng Dynasylan F 8815 silane coupling agent.

6. The degradable high barrier antibacterial film according to claim 1, wherein, the three layers of film are further tightly combined by rolling at a temperature of 60-80℃ for 1-2 min after the modified chitosan cross-linked film layer is cast into a film.