High-barrier antibacterial polyamide film and preparation method thereof

Abstract

The invention relates to the technical field of polyamide films, in particular to a high-barrier antibacterial polyamide film and a preparation method thereof. The film layer structure of the high-barrier antibacterial polyamide film provided by the invention comprises an antibacterial upper surface layer, a barrier core layer and an antibacterial lower surface layer which are sequentially arranged from top to bottom, and the antibacterial upper surface layer and the antibacterial lower surface layer particularly adopt an antibacterial agent modified layered double-metal hydroxide prepared by loading an organic antibacterial agent on a flaky filler as one of raw materials. And in addition, the MXD6-PA6 copolymer is selected as one of the raw materials of the barrier core layer, so that the barrier property is improved, and meanwhile, the flexibility of the material is considered. The invention further provides a preparation method of the high-barrier antibacterial polyamide film, the prepared high-barrier antibacterial polyamide film is applied to food packaging, the influence of oxygen and microorganisms on packaging contents can be effectively relieved, and the fresh-keeping quality of packaged food is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide films, and in particular to a high-barrier antibacterial polyamide film and a preparation method thereof. Background Art

[0002] Polyamide (PA) has excellent mechanical properties, heat resistance, chemical stability and relatively good barrier properties, and is increasingly used in the packaging field. Since the spoilage of packaged contents is mainly affected by oxygen and microorganisms, in order to extend the shelf life of the contents, high barrier properties and antibacterial properties are indispensable technical indicators for polyamide packaging.

[0003] PA6, or nylon 6, is an important variety of polyamide materials with good toughness, wear resistance, low temperature resistance and bacteria resistance; MXD6-PA6, a composite material of nylon MXD6 and nylon 6, is a high-performance engineering plastic with high mechanical strength, high rigidity and heat deformation temperature, low water absorption, good dimensional stability and good gas barrier properties.

[0004] Layered double hydroxides (LDHs) are an inorganic layered two-dimensional material composed of positively charged main layers, negatively charged interlayer anions and water molecules. The overall structure is electrically neutral and has good biocompatibility and barrier properties. The exchangeability of LDHs interlayer anions can be used to organically modify them.

[0005] On January 3, 2020, Chinese patent CN110641107A disclosed an antibacterial high barrier nylon film and its preparation method. The antibacterial high barrier nylon film includes a total of 5 film layers, from the outside to the inside, PE polyethylene protective layer, TIE resin adhesive layer, first PA polyamide layer, EVOH ethylene / vinyl alcohol copolymer layer, second PA polyamide layer. The film material has excellent antibacterial and barrier effects and is widely used in the packaging field. However, the EVOH in its EVOH ethylene / vinyl alcohol copolymer layer is greatly affected by external humidity. When the external humidity is too high, the barrier performance of the film will decrease, affecting the shelf life of food. It can be seen that how to prepare a high barrier antibacterial polyamide film is still a problem that technicians in this field need to solve. Summary of the invention

[0006] In order to solve the technical problem of how to prepare a high-barrier antibacterial polyamide film, the present invention provides a high-barrier antibacterial polyamide film, the film layer structure includes an antibacterial upper surface layer, a barrier core layer and an antibacterial lower surface layer arranged in sequence from top to bottom; The raw materials of the antibacterial upper surface layer and the antibacterial lower surface layer include 0.2% to 2.5% of a lubricant, 0.2% to 2.5% of an opening agent, 0.1% to 10% of an antibacterial agent-modified layered double metal hydroxide and 85% to 99.5% of PA6 by mass percentage; The raw materials of the barrier core layer include 50% to 70% of MXD6-PA6 copolymer and 30% to 50% of PA6 by mass percentage.

[0007] In one embodiment, the antimicrobial agent modified layered double hydroxide is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of (2-4):1, p-hydroxybenzoic acid was added in a mass volume ratio of (1-3) g: (100-200) mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add it to deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder.

[0008] In one embodiment, the lubricant is any one of erucamide, oleamide, ethylene bisstearamide, silicone powder, silicone oil, polyethylene wax, and oxidized polyethylene wax, or any combination thereof.

[0009] In one embodiment, the opening agent is any one of silicon dioxide, talc, kaolin, calcium carbonate, clay, magnesium carbonate, barium carbonate, calcium phosphate, aluminum oxide, and titanium dioxide, or any combination thereof.

[0010] In one embodiment, the PA6 content in the MXD6-PA6 copolymer is ≤30%.

[0011] In one embodiment, at least one side of the antibacterial upper surface layer or the antibacterial lower surface layer is subjected to corona treatment, and the corona value is ≥50 dyn.

[0012] In one embodiment, the thickness of the antibacterial upper surface layer and the antibacterial lower surface layer are both 2.5-5 μm.

[0013] In one embodiment, the thickness of the barrier core layer is 5-15 μm.

[0014] The present invention also provides a method for preparing the high barrier antibacterial polyamide film as described above, comprising the following steps: The raw materials of the antibacterial upper surface layer, the barrier core layer and the antibacterial lower surface layer are weighed respectively by mass percentage, stirred and mixed, and respectively put into the main machine and the auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; At least one surface of the film obtained by stretching is subjected to corona treatment, and the high barrier antibacterial polyamide film is obtained after winding.

[0015] In one embodiment, the main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265°C, the stretching temperature is 100~130°C, the setting temperature is 170~200°C, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

[0016] The high barrier antibacterial polyamide film provided by the present invention has an antibacterial upper surface layer and an antibacterial lower surface layer in the film structure, in particular, an antibacterial agent-modified layered double metal hydroxide is used as one of the raw materials, and the organic antibacterial agent is loaded with a flaky filler, which is beneficial to improving the thermal stability of the organic antibacterial agent, thereby effectively improving the antibacterial property of the obtained film. In addition, when preparing the antibacterial agent-modified layered double metal hydroxide, ZnSO4•7H2O and Al2(SO)4•18H2O with high crystalline water content are specially selected to prepare zinc-aluminum-based LDHs, Zn 2+ The higher the ratio, the better the relative antibacterial property, while a high content of crystalline water is beneficial to improving the adsorption capacity of LDHs, promoting the loading of organic antimicrobial agents, and synergistically improving the antibacterial performance.

[0017] The high barrier antibacterial polyamide film provided by the present invention adopts MXD6-PA6 copolymer as the main raw material of the barrier core layer. Compared with the 100% PA6 barrier core layer, the barrier performance is greatly improved, and compared with the 100% MXD6 barrier core layer, the barrier performance is only slightly reduced, but the antibacterial property and flexibility of the film are improved simultaneously, so that the overall performance of the prepared polyamide film is greatly improved, while having both high barrier and antibacterial properties, and good flexibility, which is conducive to processing and production.

[0018] In summary, compared with the prior art, the high barrier antibacterial polyamide film provided by the present invention has high barrier and antibacterial properties, can effectively reduce the impact of oxygen and microorganisms on the package contents, extend its shelf life, and reduce waste caused by spoilage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1This is a schematic diagram of the membrane structure of the high barrier antibacterial polyamide film provided in Example 1 of the present invention.

[0021] Reference numerals: DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] Example 1 This embodiment provides a high barrier antibacterial polyamide film, such as Figure 1 As shown, the film layer structure includes an antibacterial upper surface layer 1, a barrier core layer 2 and an antibacterial lower surface layer 3 which are arranged in sequence from top to bottom.

[0025] The high barrier antibacterial polyamide film is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of 2:1, p-hydroxybenzoic acid was added in a mass volume ratio of 1 g:100 mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder to obtain an antibacterial agent modified layered double metal hydroxide; The raw materials of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 are weighed respectively by mass percentage: 2.5% lubricant, 2.5% antibacterial agent, 5% antibacterial agent modified layered double metal hydroxide and 90% PA6; The raw materials of the barrier core layer 2 are weighed according to mass percentage: 70% MXD6-PA6 copolymer and 30% PA6; The weighed antibacterial upper surface layer raw material, antibacterial lower surface layer raw material and barrier core layer raw material are stirred and mixed, and respectively put into the main machine and auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; Performing corona treatment on at least one surface of the film obtained by stretching, and rolling up to obtain the high barrier antibacterial polyamide film; Among them, the corona value of corona treatment is ≥50 dyn; The thickness of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 is 2.5 μm, and the thickness of the barrier core layer 2 is 10 μm; The main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265℃, the stretching temperature is 100~130℃, the setting temperature is 170~200℃, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

[0026] Example 2 This embodiment provides a high barrier antibacterial polyamide film, such as Figure 1 As shown, the film layer structure includes an antibacterial upper surface layer 1, a barrier core layer 2 and an antibacterial lower surface layer 3 which are arranged in sequence from top to bottom.

[0027] The high barrier antibacterial polyamide film is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of 4:1, p-hydroxybenzoic acid was added in a mass volume ratio of 1 g:200 mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder to obtain an antibacterial agent modified layered double metal hydroxide; The raw materials of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 are weighed respectively by mass percentage: 2.5% lubricant, 2.5% antibacterial agent, 5% antibacterial agent modified layered double metal hydroxide and 85% PA6; The raw materials of the barrier core layer 2 are weighed according to mass percentage: 50% MXD6-PA6 copolymer and 50% PA6; The weighed antibacterial upper surface layer raw material, antibacterial lower surface layer raw material and barrier core layer raw material are stirred and mixed, and respectively put into the main machine and auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; Performing corona treatment on at least one surface of the film obtained by stretching, and rolling up to obtain the high barrier antibacterial polyamide film; Among them, the corona value of corona treatment is ≥50 dyn; The thickness of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 is 2.5 μm, and the thickness of the barrier core layer 2 is 10 μm; The main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265℃, the stretching temperature is 100~130℃, the setting temperature is 170~200℃, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

[0028] Example 3 This embodiment provides a high barrier antibacterial polyamide film, such as Figure 1 As shown, the film layer structure includes an antibacterial upper surface layer 1, a barrier core layer 2 and an antibacterial lower surface layer 3 which are arranged in sequence from top to bottom.

[0029] The high barrier antibacterial polyamide film is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of 2:1, p-hydroxybenzoic acid was added in a mass volume ratio of 3 g:100 mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder to obtain an antibacterial agent modified layered double metal hydroxide; The raw materials of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 are weighed respectively by mass percentage: 0.25% lubricant, 0.25% antibacterial agent, 10% antibacterial agent modified layered double metal hydroxide and 89.5% PA6; The raw materials of the barrier core layer 2 are weighed according to mass percentage: 70% MXD6-PA6 copolymer and 30% PA6; The weighed antibacterial upper surface layer raw material, antibacterial lower surface layer raw material and barrier core layer raw material are stirred and mixed, and respectively put into the main machine and auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; Performing corona treatment on at least one surface of the film obtained by stretching, and rolling up to obtain the high barrier antibacterial polyamide film; Among them, the corona value of corona treatment is ≥50 dyn; The thickness of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 is 2.5 μm, and the thickness of the barrier core layer 2 is 10 μm; The main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265℃, the stretching temperature is 100~130℃, the setting temperature is 170~200℃, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

[0030] Example 4 This embodiment provides a high barrier antibacterial polyamide film, such as Figure 1 As shown, the film layer structure includes an antibacterial upper surface layer 1, a barrier core layer 2 and an antibacterial lower surface layer 3 which are arranged in sequence from top to bottom.

[0031] The high barrier antibacterial polyamide film is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of 2:1, p-hydroxybenzoic acid was added in a mass volume ratio of 3 g:100 mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder to obtain an antibacterial agent modified layered double metal hydroxide; The raw materials of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 are weighed respectively by mass percentage: 1.0% lubricant, 1.0% opening agent, 10% antibacterial agent modified layered double metal hydroxide and 88% PA6; The raw materials of the barrier core layer 2 are weighed according to mass percentage: 70% MXD6-PA6 copolymer and 30% PA6; The weighed antibacterial upper surface layer raw material, antibacterial lower surface layer raw material and barrier core layer raw material are stirred and mixed, and respectively put into the main machine and auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; Performing corona treatment on at least one surface of the film obtained by stretching, and rolling up to obtain the high barrier antibacterial polyamide film; Among them, the corona value of corona treatment is ≥50 dyn; The thickness of the antibacterial upper surface layer 1 and the antibacterial lower surface layer 3 is 2.5 μm, and the thickness of the barrier core layer 2 is 10 μm; The main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265℃, the stretching temperature is 100~130℃, the setting temperature is 170~200℃, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

[0032] The present invention also provides the following comparative example for preparing a polyamide film: Comparative Example 1 The difference between this comparative example and Example 1 of the present invention is that an unmodified layered double metal hydroxide is used as the antibacterial agent.

[0033] The unmodified layered double metal hydroxide is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of 2:1, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried. An appropriate amount of the dried product was added into deionized water containing stearic acid, and the mixture was stirred for reaction for 12 h. After washing and drying, the mixture was ground into powder to obtain an unmodified layered double metal hydroxide.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 of the present invention is that the barrier core layer is 100% MXD6.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 of the present invention is that the barrier core layer is 100% PA6.

[0036] The high barrier antibacterial polyamide films prepared in the above Examples 1 to 4 and the polyamide films prepared in the above Comparative Examples 1 to 3 were tested for tensile strength and elongation at break in accordance with GB / T 1040 Determination of tensile properties of plastics, barrier properties were tested in accordance with ASTM D3985 Standard test method for measuring oxygen transmission rate through plastic films and sheets using a coulometric sensor, and antibacterial properties were tested in accordance with GB / T 31402 Determination of antibacterial activity on the surface of plastics and other non-porous materials. When evaluating the barrier properties and antibacterial properties, the best performance was "★★★★★" and the worst was "☆☆☆☆☆", and the more "★", the better the performance; the test results are listed in Table 1.

[0037] Table 1 Performance test table of polyamide films prepared in Examples 1 to 4 and Comparative Examples 1 to 3

[0038] According to the performance test results of Comparative Example 1 and Example 1 in Table 1, the use of layered double hydroxide modified with an organic antibacterial agent as one of the raw materials for the antibacterial upper surface layer and the antibacterial lower surface layer can greatly improve the antibacterial properties of the film; and by comparing Example 1 with Example 3, it can be seen that the antibacterial properties of the film can be further improved after the addition amount of the organic antibacterial agent p-hydroxybenzoic acid is increased to a mass volume ratio of 3g:100mL.

[0039] It can be seen from Comparative Examples 2 and 3 that the barrier performance of the 100% MXD6 barrier core layer is much better than that of the 100% PA6 barrier core layer. From Comparative Examples 2 and 3 and Example 1, it can be seen that although the barrier property of the MXD6-PA6 barrier core layer is slightly worse than that of the 100% MXD6 barrier core layer, it is sufficient to significantly improve the barrier performance of the film, and the elongation at break data is also greatly optimized, that is, the polyamide film using MXD6-PA6 as the barrier core layer has better flexibility and is more suitable for the application of packaging film materials.

[0040] Although the terms such as high barrier and antibacterial are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high barrier antibacterial polyamide film, characterized in that: The membrane layer structure comprises an antibacterial upper surface layer (1), a barrier core layer (2) and an antibacterial lower surface layer (3) which are arranged in sequence from top to bottom; The raw materials of the antibacterial upper surface layer (1) and the antibacterial lower surface layer (3) include, by mass percentage, 0.2% to 2.5% of a lubricant, 0.2% to 2.5% of an opening agent, 0.1% to 10% of an antibacterial agent-modified layered double metal hydroxide, and 85% to 99.5% of PA6; The raw materials of the barrier core layer (2) include 50% to 70% of MXD6-PA6 copolymer and 30% to 50% of PA6 by mass percentage.

2. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The antibacterial agent modified layered double metal hydroxide is prepared according to the following steps: ZnSO4•7H2O and Al2(SO)4•18H2O were prepared into a solution with a total metal ion concentration of 1.0 mol / L in a molar ratio of (2-4):1, p-hydroxybenzoic acid was added in a mass volume ratio of (1-3) g: (100-200) mL, and the pH was adjusted to 8-10 with NaOH solution. The mixed solution was placed in a ball mill for reaction for 10 min, then taken out, aged for 12 h, filtered, washed, and dried; Take an appropriate amount of the dried product and add it to deionized water containing stearic acid, stir and react for 12 h, wash, dry and grind into powder.

3. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The lubricant is any one of erucamide, oleamide, ethylenebisstearamide, silicone powder, silicone oil, polyethylene wax, and oxidized polyethylene wax, or any combination thereof.

4. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The anti-blocking agent is any one or any combination of silicon dioxide, talc, kaolin, calcium carbonate, clay, magnesium carbonate, barium carbonate, calcium phosphate, aluminum oxide, and titanium dioxide.

5. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The PA6 content in the MXD6-PA6 copolymer is ≤30%.

6. The high barrier antibacterial polyamide film according to claim 1, characterized in that: At least one side of the antibacterial upper surface layer (1) or the antibacterial lower surface layer (3) is subjected to corona treatment, and the corona value is ≥50 dyn.

7. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The thickness of the antibacterial upper surface layer (1) and the antibacterial lower surface layer (3) are both 2.5-5 μm.

8. The high barrier antibacterial polyamide film according to claim 1, characterized in that: The thickness of the barrier core layer (2) is 5-15 μm.

9. A method for preparing the high barrier antibacterial polyamide film according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials of the antibacterial upper surface layer, the barrier core layer and the antibacterial lower surface layer are weighed respectively by mass percentage, stirred and mixed, and respectively put into the main machine and the auxiliary machine of the three-layer co-extrusion casting machine for melt extrusion to obtain a composite casting sheet; The composite casting sheet is subjected to biaxial stretching and then subjected to shaping heat treatment; At least one surface of the film obtained by stretching is subjected to corona treatment, and the high barrier antibacterial polyamide film is obtained after winding.

10. The method for preparing a high barrier antibacterial polyamide film according to claim 9, characterized in that: The main machine speed of the three-layer co-extrusion casting machine is 10~25 rpm, the auxiliary machine speed is 3~10 rpm, the processing temperature is 230~265℃, the stretching temperature is 100~130℃, the setting temperature is 170~200℃, and the stretching ratio is (2.5×2.5)~(3.5×3.5).

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