Antibacterial aluminum foil material for lunch box and preparation method of antibacterial aluminum foil material

Abstract

The invention relates to the technical field of food packaging, in particular to a bacteriostatic aluminum foil material for a meal box and a preparation method thereof. The material is subjected to aluminum foil surface activation, then is sequentially impregnated in a sol impregnation liquid and an outer layer coating liquid, is subjected to dip coating, and finally is subjected to ultraviolet curing to obtain a multi-layer composite structure. The middle layer is made of an aminated organic silicon material and is firmly combined with the aluminum base material and the outer layer resin through chemical bonds, so that the adhesive force of the coating is remarkably improved. The outer coating is added with a phenyl triazole modified layered double hydroxide loaded nano-silver antibacterial agent, so that slow release and efficient broad-spectrum antibacterial property of silver ions are realized, the thermal stability is improved, and reliable performance under a high-temperature condition is ensured. The multilayer design and multiple antibacterial mechanisms have a synergistic effect, the problems of poor antibacterial durability, insufficient adhesive force, low heat resistance and the like of a traditional lunch box aluminum foil material are effectively solved, meanwhile, food safety is considered, and the aluminum foil material is suitable for the field of modern high-requirement food packaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food packaging, in particular to a bacteriostatic aluminum foil material for lunch boxes and a preparation method thereof. BACKGROUND

[0002] With the continuous improvement of people's awareness of food safety, the antibacterial performance of packaging materials for lunch boxes has attracted increasing attention. As an important material for food packaging, aluminum foil has good barrier property, thermal conductivity and formability, and is widely used in the manufacture of various lunch boxes. However, traditional aluminum foil does not have antibacterial function and is prone to bacterial growth during use, affecting food safety.

[0003] Currently, the methods for imparting antibacterial function to aluminum foil mainly include surface coating of antibacterial agents and chemical modification treatment. Common antibacterial coating technologies include organic antibacterial agent coating, inorganic antibacterial agent loading, and silver ion slow-release system. Among them, silver-based antibacterial materials are favored due to their broad-spectrum antibacterial property and relative safety. However, the existing technology still has many problems in practical application.

[0004] Firstly, the adhesion of antibacterial coating to aluminum substrate is generally insufficient. Traditional direct coating methods can only form physical bonding, lacking chemical bonding, which leads to easy peeling of the coating during use, especially under the action of heat treatment or mechanical stress. Peeling of the coating not only reduces the antibacterial effect, but also may cause migration of silver ions and other antibacterial components into food, causing safety hazards.

[0005] Secondly, the dispersibility and stability of antibacterial agents in the coating need to be improved. Nanosilver and other antibacterial particles are prone to agglomeration in the polymer matrix, forming aggregates of uneven size and reducing antibacterial efficiency. At the same time, the release rate of silver ions is difficult to accurately control, and the initial rapid release will lead to the attenuation of antibacterial ability in the later period, making it impossible to achieve long-term antibacterial effect.

[0006] Thirdly, the thermal stability of existing antibacterial coatings is generally poor. Lunch boxes often need to undergo high temperature treatment during production and use, such as heat sealing, microwave heating, etc., which puts high requirements on the thermal stability of the coating. Traditional coatings are prone to thermal decomposition, oxidation or phase separation under high temperature environment, resulting in rapid decrease of antibacterial property and serious deterioration of adhesion.

[0007] In addition, the problem of interfacial compatibility of the coating cannot be ignored. The interface between different material layers is often the weak link of the entire composite structure, and interface defects will become stress concentration points and corrosion channels, affecting the overall performance and service life of the material. Especially in a humid and hot environment, delamination phenomenon is prone to occur at the interface.

[0008] The prior art also has the problem of single antibacterial mechanism. The antibacterial mode relying on silver ion release alone is prone to drug resistance, and the inhibition effect on different types of bacteria is different. The lack of synergistic effect of multiple antibacterial mechanisms makes it difficult to achieve long-term antibacterial effect with broad-spectrum and high efficiency.

[0009] In view of the above technical problems, it is urgent to develop a kind of antibacterial aluminum foil material for lunch box with excellent adhesion, long-term antibacterial performance and good thermal stability to meet the strict requirements of modern food packaging. SUMMARY

[0010] Therefore, the purpose of the present application is to provide an antibacterial aluminum foil material for lunch box and a preparation method thereof to solve the problems of poor antibacterial durability, insufficient coating adhesion and poor heat resistance of the existing antibacterial coating of aluminum foil for lunch box.

[0011] Based on the above purpose, the present application provides an antibacterial aluminum foil material for lunch box, which is obtained by dipping and drawing plating film of aluminum foil in a sol dipping solution and then dipping and drawing plating film in an outer layer plating solution.

[0012] Preferably, the aluminum foil is subjected to surface activation treatment before dipping and drawing plating film in the sol dipping solution, and the specific steps are as follows: the aluminum foil is sequentially immersed in acetone and anhydrous ethanol, ultrasonic treated, and then subjected to plasma activation treatment.

[0013] Preferably, the power of the plasma activation treatment is 80-120W, the atmosphere is 15-25Pa oxygen, and the time is 10-20min.

[0014] Preferably, the dipping and drawing plating film in the sol dipping solution is at a drawing rate of 80-120mm / min and 2-4 times.

[0015] Preferably, the dipping and drawing plating film in the outer layer plating solution is at a drawing rate of 40-60mm / min and 2-4 times.

[0016] Further, the sol dipping solution includes the following raw materials by weight fraction: 1-3 parts of tetraethyl orthosilicate, 0.3-0.8 parts of γ-aminopropyl triethoxysilane, 40-60 parts of anhydrous ethanol and 3-8 parts of deionized water.

[0017] Further, the outer layer plating solution includes the following raw materials by weight fraction: 0.8-1.2 parts of hexafluorobutyl acrylate, 1.5-2.5 parts of glycidyl methacrylate, 2-4 parts of bisphenol A type epoxy acrylate, 0.05-0.15 parts of photoinitiator, 0.4-0.6 parts of antibacterial agent and 20-30 parts of acetone.

[0018] Further, the preparation steps of the antibacterial agent are as follows S1: γ-glycidoxypropyltrimethoxysilane modified layered double hydroxide, to obtain an epoxidized layered double hydroxide; S2: the epoxidized layered double hydroxide and propargylamine are subjected to an epoxy ring-opening reaction, to obtain an alkinylated layered double hydroxide; S3: the alkinylated layered double hydroxide and azidobenzene are subjected to an azide-yne cycloaddition reaction under the catalysis of cuprous bromide and sodium ascorbate, to obtain a phenyltriazole modified layered double hydroxide; S4: after the phenyltriazole modified layered double hydroxide is loaded with silver nitrate, it is subjected to UV irradiation reduction, to obtain an antibacterial agent.

[0019] Preferably, the weight ratio of γ-glycidoxypropyltrimethoxysilane and layered double hydroxide in step S1 is 0.2-0.4:0.4-0.6.

[0020] Preferably, the layered double hydroxide in step S1 is zinc-aluminum layered double hydroxide, with a Zn / Al molar ratio of 2:1 and a flake diameter of 1-4 μm.

[0021] Preferably, the weight ratio of epoxidized layered double hydroxide and propargylamine in step S2 is 0.4-0.6:0.15-0.25.

[0022] Preferably, the weight ratio of alkinylated layered double hydroxide, azidobenzene, cuprous bromide and sodium ascorbate in step S3 is 0.4-0.6:0.2-0.3:0.04-0.06:0.12-0.18.

[0023] Preferably, the weight ratio of phenyltriazole modified layered double hydroxide and silver nitrate in step S4 is 0.4-0.6:0.016-0.024.

[0024] Preferably, the irradiation intensity of the UV irradiation reduction in step S4 is 30-50 mW / cm 2 , the irradiation time is 10-14 min, and the wavelength is 254 nm.

[0025] Further, the present application also provides a preparation method of an antibacterial aluminum foil material for meal boxes, comprising the following steps: (1) tetraethyl orthosilicate and γ-aminopropyltriethoxysilane are added to a mixed solution of anhydrous ethanol and deionized water, stirred at room temperature for 8-12 min, the pH is adjusted to 9.1-9.3 with ammonia water, and stirring is continued for 20-40 min, to obtain a sol immersion solution; a surface-activated aluminum foil is immersed in the sol immersion solution in a vertical direction, and a film is plated by dip-coating; after the dip-coating is completed, the aluminum foil is dried, to obtain an aminated organosilicon coated aluminum foil; (2) Put hexafluorobutyl acrylate, glycidyl methacrylate, bisphenol A type epoxy acrylate, photoinitiator and antibacterial agent into acetone, ultrasonic for 20-40 min, to obtain the outer coating solution, dip the amino-organic silicon coated aluminum foil into the outer coating solution in the vertical direction, dip and draw the coating, after drawing, dry, ultraviolet radiation curing, to obtain the antibacterial aluminum foil material for lunch box.

[0026] Preferably, the radiation intensity of the ultraviolet radiation curing in the step (2) is 80-120 mW / cm 2 , the time is 80-100 seconds, and the wavelength is 365 nm.

[0027] The present application effectively solves the technical problems existing in the traditional antibacterial aluminum foil material by constructing a multi-layer composite structure design, and has the following remarkable beneficial effects: Excellent coating adhesion: the present application uses amino-organic silicon as the intermediate transition layer, forms stable chemical bonding with the aluminum substrate through siloxane bond, and the amino functional groups on the surface can crosslink with the outer resin, forming a gradient interface structure from the substrate to the coating. This molecular-level chemical bonding significantly improves the adhesion of the coating and effectively prevents the phenomenon of falling off during use.

[0028] Long-acting and stable antibacterial performance: the present application realizes the uniform dispersion and stable loading of nano-silver by modifying the layered double hydroxide carrier with phenyl triazole. The triazole ring structure provides an ideal coordination environment for silver ions, effectively controls the release rate of silver ions, and avoids the problem of decay of antibacterial ability in the later period caused by initial excessive release. The ion exchange characteristics of the layered carrier further enhance the slow-release effect of silver ions, ensuring the persistence and effectiveness of the antibacterial activity.

[0029] Excellent thermal stability: the present application significantly improves the glass transition temperature and thermal decomposition temperature of the coating system by introducing aromatic components and constructing π-π interaction network. The intermolecular forces between phenyl triazole and aromatic components in the resin form physical crosslinking points, enhancing the structural stability at high temperature. At the same time, the buffering effect of the amino-organic silicon intermediate layer effectively reduces the thermal expansion stress and prevents interface cracking.

[0030] Good interface compatibility: the present application realizes good compatibility between different material layers through careful design of surface modification strategy. The π-π stacking effect between the aromatic structure of phenyl triazole and the resin matrix enhances the dispersion stability of the antibacterial agent and reduces interface defects. The synergistic effect of multiple chemical and physical interactions ensures the tight bonding between the layers of the composite material.

[0031] Broad-spectrum and high-efficiency antibacterial mechanism: the present application combines silver ion release and the antibacterial effect of the carrier itself to form a multiple antibacterial mechanism. The layered double hydroxide carrier has natural antibacterial activity, and the synergistic effect with nano-silver further enhances the inhibitory capacity for various pathogenic bacteria, effectively preventing the generation of drug resistance.

[0032] Good food safety: the present application maximally reduces the migration risk of the antibacterial component into food through a controllable silver ion release mechanism and a stable coating structure. The multiple-layer composite structure forms an effective barrier to ensure the food safety of the aluminum foil material for lunch boxes. DETAILED DESCRIPTION

[0033] In order to make the objects, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to specific examples. EXAMPLE

[0034] (1) An aluminum foil (1235 alloy) with a size of 200 mm x 200 mm and a thickness of 0.06 mm was immersed in acetone and cleaned in an ultrasonic cleaner at 40 kHz for 8 min. After being taken out, it was immediately transferred to anhydrous ethanol and cleaned by ultrasonic for another 8 min. After being taken out, the surface of the aluminum foil was dried by blowing nitrogen. The dried aluminum foil was immediately placed in a plasma reaction chamber, 15 Pa of oxygen was introduced, and plasma activation treatment was carried out at a radio frequency power of 80 W for 10 min to obtain a surface-activated aluminum foil. (2) 1 g of tetraethyl orthosilicate and 0.3 g of γ-aminopropyl triethoxysilane were added to a mixed solution of 40 g of anhydrous ethanol and 3 g of deionized water. After being stirred at room temperature for 8 min, the pH was adjusted to 9.1 with ammonia water with a concentration of 28 wt%. The stirring was continued for 20 min to obtain a sol dipping solution. The surface-activated aluminum foil was immersed in the sol dipping solution along the vertical direction and slowly pulled out of the liquid surface at a rate of 80 mm / min to complete one coating pulling. After being left to stand for 8 min, the pulling was repeated twice (a total of three times). After the pulling was completed, the sample was dried at 75°C for 50 min to obtain an aminosilicone-coated aluminum foil. (3) 0.4 g of zinc-aluminum layered double hydroxide (Zn / Al molar ratio 2:1, flake diameter 1-4 μm) was dispersed in 15 g of anhydrous ethanol and 1 g of deionized water and ultrasonicated for 20 min. Then, 0.2 g of γ-glycidyloxypropyltrimethoxysilane was added, and the pH was adjusted to 8.7 with ammonia water with a concentration of 28 wt%. The stirring was carried out at 55°C for 5 h. After being centrifuged, the sample was washed with deionized water for 3 times and vacuum dried to obtain an epoxidized layered double hydroxide. (4) 0.4 g of the epoxidized layered double hydroxide was added to 40 g of toluene and ultrasonicated for 20 min. Then, 0.15 g of propargylamine was added, and the stirring was carried out at 65°C for 20 h. After being centrifuged, the sample was washed with anhydrous ethanol for 3 times to obtain an alkyne-derivatized layered double hydroxide. (5) 0.4 g of the alkyne-modified layered double hydroxide and 0.2 g of azidobenzene were added to 20 g of N,N-dimethylformamide under a nitrogen atmosphere, and ultrasonicated for 20 min. Then, 0.04 g of cuprous bromide and 0.12 g of sodium ascorbate were added, and the reaction was stirred at 35 °C for 2 h. After centrifugation, the product was washed with anhydrous ethanol three times and dried under vacuum to obtain a phenyltriazole-modified layered double hydroxide; (6) 0.4 g of the phenyltriazole-modified layered double hydroxide was added to 10 g of deionized water, and ultrasonicated for 20 min. Then, 0.2 g of a 8 wt% silver nitrate aqueous solution was added, and the mixture was stirred in the dark for 20 min. Then, the mixture was irradiated with a 254 nm ultraviolet lamp at an intensity of 30 mW / cm 2 for 10 min. After centrifugation, the product was washed with deionized water three times and dried under vacuum to obtain an antibacterial agent; (7) 0.8 g of hexafluorobutyl acrylate, 1.5 g of glycidyl methacrylate, 2 g of bisphenol A type epoxy acrylate CN104, 0.05 g of a photoinitiator 184, and 0.4 g of the antibacterial agent were added to 20 g of acetone, and ultrasonicated for 20 min. Then, the amino-silicone-coated aluminum foil was immersed in the liquid, and slowly pulled out of the liquid surface at a rate of 40 mm / min to complete one coating pull. After standing for 8 min, the pull was repeated twice (a total of three times). After the pull was completed, the aluminum foil was dried at 65 °C for 8 min, and then irradiated with a 365 nm ultraviolet lamp at an intensity of 80 mW / cm 2 for 80 s to obtain a bacteriostatic aluminum foil material for a lunch box. Example

[0035] (1) An aluminum foil (1235 alloy) with a size of 200 mm x 200 mm and a thickness of 0.06 mm was immersed in acetone and cleaned in an ultrasonic cleaner at 40 kHz for 10 min. After being taken out, the aluminum foil was immediately transferred to anhydrous ethanol and cleaned again for 10 min. The surface of the dried aluminum foil was blown dry with nitrogen, and the dried aluminum foil was immediately placed in a plasma reaction chamber. Oxygen was introduced at a flow rate of 20 Pa, and plasma activation treatment was performed at a radio frequency power of 100 W for 15 min to obtain a surface-activated aluminum foil; (2) 2 g of tetraethyl orthosilicate and 0.5 g of γ-aminopropyl triethoxysilane were added to a mixed solution of 50 g of anhydrous ethanol and 5 g of deionized water, and stirred at room temperature for 10 min. The pH was adjusted to 9.2 with 28 wt% ammonia water, and the stirring was continued for 30 min to obtain a sol dipping solution. The surface-activated aluminum foil was immersed in the sol dipping solution in a vertical direction, and slowly pulled out of the liquid surface at a rate of 100 mm / min to complete one coating pull. After standing for 10 min, the pull was repeated twice (a total of three times). After the pull was completed, the aluminum foil was dried at 80 °C for 60 min to obtain an amino-silicone-coated aluminum foil; (3) 0.5 g of zinc-aluminum layered double hydroxide (Zn / Al molar ratio 2:1, flake size 1-4 μm) was dispersed in 20 g of absolute ethanol and 2 g of deionized water, and ultrasonicated for 30 min. Then, 0.3 g of γ-glycidoxypropyltrimethoxysilane was added, and the pH was adjusted to 8.9 with ammonia water having a concentration of 28 wt%. The mixture was stirred at 60°C for 6 h, centrifuged, washed with deionized water three times, and vacuum dried to obtain an epoxidized layered double hydroxide; (4) 0.5 g of the epoxidized layered double hydroxide was added to 50 g of toluene, and ultrasonicated for 30 min. Then, 0.2 g of propargylamine was added, and the mixture was stirred at 70°C for 24 h. The mixture was centrifuged, washed with absolute ethanol three times, and the propargylated layered double hydroxide was obtained; (5) 0.5 g of the propargylated layered double hydroxide and 0.25 g of phenyl azide were added to 30 g of N,N-dimethylformamide under a nitrogen atmosphere, and ultrasonicated for 30 min. Then, 0.05 g of cuprous bromide and 0.15 g of sodium ascorbate were added, and the mixture was stirred at 40°C for 3 h. The mixture was centrifuged, washed with absolute ethanol three times, and vacuum dried to obtain a phenyltriazole-modified layered double hydroxide; (6) 0.5 g of the phenyltriazole-modified layered double hydroxide was added to 15 g of deionized water, and ultrasonicated for 30 min. Then, 0.3 g of a silver nitrate aqueous solution having a concentration of 10 wt% was added, and the mixture was stirred in the dark for 30 min. The mixture was then irradiated with ultraviolet light at a wavelength of 254 nm at an intensity of 40 mW / cm 2 for 12 min. The mixture was centrifuged, washed with deionized water three times, and vacuum dried to obtain an antibacterial agent; (7) 1 g of hexafluorobutyl acrylate, 2 g of glycidyl methacrylate, 3 g of bisphenol A type epoxy acrylate CN104, 0.1 g of photoinitiator 184, and 0.5 g of the antibacterial agent were added to 25 g of acetone, and ultrasonicated for 30 min. Then, an aminated organosilicon-coated aluminum foil was immersed in the liquid, and pulled out of the liquid surface at a rate of 50 mm / min to complete one coating pull. After 10 min, the pull was repeated twice (a total of three times). After the pull was completed, the aluminum foil was dried at 70°C for 10 min, and then irradiated with ultraviolet light at a wavelength of 365 nm at an intensity of 100 mW / cm 2 for 90 seconds to obtain an antibacterial aluminum foil material for a lunch box. Example

[0036] (1) An aluminum foil (1235 alloy) having a size of 200 mm x 200 mm and a thickness of 0.06 mm was immersed in acetone, and cleaned in an ultrasonic cleaner at 40 kHz for 12 min. The aluminum foil was immediately transferred to absolute ethanol after being taken out, and cleaned in an ultrasonic cleaner for another 12 min. The surface of the aluminum foil was dried with nitrogen, and the dried aluminum foil was immediately placed in a plasma reaction chamber. Oxygen was introduced at a pressure of 25 Pa, and the aluminum foil was plasma-activated at a radio frequency power of 120 W for 20 min to obtain a surface-activated aluminum foil. (2) 3 g of tetraethyl orthosilicate and 0.8 g of γ-aminopropyltriethoxysilane were added to a mixed solution of 60 g of anhydrous ethanol and 8 g of deionized water, stirred at room temperature for 12 min, adjusted to pH 9.3 with ammonia water with a concentration of 28 wt%, and continued to stir for 40 min to obtain a sol immersion solution. The surface-activated aluminum foil was immersed in the sol immersion solution in the vertical direction, slowly pulled out of the liquid surface at a rate of 120 mm / min, and the coating pulling was completed once. After standing for 12 min, the pulling was repeated twice (a total of three times). After the pulling was completed, it was dried at 85°C for 70 min to obtain an aminated organosilicon coated aluminum foil; (3) 0.6 g of zinc-aluminum layered double hydroxide (Zn / Al molar ratio 2:1, flake diameter 1-4 μm) was dispersed in 25 g of anhydrous ethanol and 3 g of deionized water, ultrasonicated for 40 min, and then 0.4 g of γ-glycidyloxypropyltrimethoxysilane was added. The pH was adjusted to 9.2 with ammonia water with a concentration of 28 wt%, and stirred at 65°C for 7 h. After centrifugation, it was washed with deionized water 3 times and vacuum dried to obtain an epoxidized layered double hydroxide; (4) 0.6 g of the epoxidized layered double hydroxide was added to 60 g of toluene, ultrasonicated for 40 min, and then 0.25 g of propargylamine was added. It was stirred at 75°C for 28 h, centrifuged, and washed with anhydrous ethanol 3 times to obtain an acetylenylated layered double hydroxide; (5) 0.6 g of the acetylenylated layered double hydroxide and 0.3 g of azidobenzene were added to 40 g of N,N-dimethylformamide under a nitrogen atmosphere, ultrasonicated for 40 min, and then 0.06 g of cuprous bromide and 0.18 g of sodium ascorbate were added. It was stirred at 45°C for 4 h, centrifuged, washed with anhydrous ethanol 3 times, and vacuum dried to obtain a phenyltriazole-modified layered double hydroxide; (6) 0.6 g of the phenyltriazole-modified layered double hydroxide was added to 20 g of deionized water, ultrasonicated for 40 min, and then 0.4 g of a 12 wt% silver nitrate aqueous solution was added. It was stirred in the dark for 40 min, and then irradiated under a 254 nm ultraviolet lamp at an intensity of 50 mW / cm 2 for 14 min. After centrifugation, it was washed with deionized water 3 times and vacuum dried to obtain an antibacterial agent; (7) 1.2 g of hexafluorobutyl acrylate, 2.5 g of glycidyl methacrylate, 4 g of bisphenol A type epoxy acrylate CN104, 0.15 g of photoinitiator 184, and 0.6 g of the antibacterial agent were added to 30 g of acetone, ultrasonicated for 40 min, and then the aminated organosilicon coated aluminum foil was immersed and slowly pulled out of the liquid surface at a rate of 60 mm / min to complete the coating pulling once. After standing for 12 min, the pulling was repeated twice (a total of three times). After the pulling was completed, it was dried at 75°C for 12 min, and then placed under a 365 nm ultraviolet lamp at an intensity of 120 mW / cm 2The intensity of the irradiation is 80-100 seconds, and the antibacterial aluminum foil material for meal boxes is obtained.

[0037] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the amino-silicone coated aluminum foil in step (7) is replaced by surface-activated aluminum foil.

[0038] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that the phenyl triazole modified layered double hydroxide in step (6) is replaced by zinc-aluminum layered double hydroxide.

[0039] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that the azide benzene in step (5) is replaced by 1-azidopropane.

[0040] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that the bisphenol A type epoxy acrylate CN104 in step (7) is replaced by ethyl methacrylate.

[0041] Performance test: Antibacterial performance test: according to GB / T 31402-2015, each aluminum foil was cut into a 50mm×50mm sample, sterilized by irradiation in a UV sterilization box (254nm, 30W) for 30min, and Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were cultured, with a concentration of 1×10 6 CFU / mL, 100μL of the bacterial solution was added to the surface of the sample, covered with a sterilized PET film, and placed in a 37℃ / 90%RH environment for 24h, then the bacteria on the surface of the sample were eluted with 0.9%NaCl solution, gradient diluted and plated on nutrient agar plates, and incubated at 37℃ for 48h, then the number of colonies was counted and the antibacterial rate was calculated, and the results are shown in Table 1.

[0042] Coating adhesion test: according to GB / T 9286-1998, a blade was used to cut a 6×6 grid (2mm apart) on the surface of the coating, the cutting depth reached the aluminum substrate, a 3M transparent tape (width 18mm) was pressed onto the grid area, and was quickly torn off at a 90° angle, the peeling ratio of the coating was observed under a microscope, and was rated according to the 0-5 scale, with 0 indicating no peeling, and the results are shown in Table 1.

[0043] Thermal stability test: the sample was placed in a 150℃ air oven for 120min, and the E. coli antibacterial rate and coating adhesion after aging were measured, and the results are shown in Table 1.

[0044] Table 1 Performance test results E. coli inhibition rate / % S. aureus inhibition rate / % Coating adhesion level E. coli inhibition rate / % after aging Coating adhesion level after aging Example 1 99.2 98.8 1 96.7 2 Example 2 99.9 99.5 0 98.3 1 Example 3 99.1 98.6 0 96.0 0 Comparative Example 1 99.3 99.2 3 90.4 5 Comparative Example 2 84.6 82.3 2 75.6 3 Comparative Example 3 92.7 90.8 1 83.5 3 Comparative Example 4 97.3 96.1 2 89.2 3 Data analysis: The meal box bacteriostatic aluminum foil material prepared by the present application exhibits excellent comprehensive performance in Examples 1-3. The data shows that it has significant bacteriostatic effect on both Escherichia coli and Staphylococcus aureus, and the coating adhesion is outstanding, and after heat aging, it can still maintain high bacteriostatic ability and adhesion stability. The sustainability of such performance may be due to the multi-layer composite structure design of the material: the aminosilicone coating as the intermediate layer forms a stable bond with the aluminum substrate through siloxane bonds, and at the same time, the amino functional groups on its surface provide active reaction sites for the outer resin, promoting the ring-opening crosslinking of the epoxy groups, thereby enhancing the interlayer bonding force. The phenyl triazole modified layered double hydroxide carrier in the antibacterial agent forms molecular entanglement with the aromatic ring structure in the resin through π-π interaction, optimizing the dispersion and immobilization of the antibacterial silver nanoparticles, ensuring the slow release effect of silver ions.

[0045] Example 2 exhibits more excellent heat resistance than Comparative Example 1. After omitting the aminosilicone coating in Comparative Example 1, the adhesion is significantly reduced, especially after heat aging. This indicates that the aminosilicone coating plays a key role in the system: its amino functional groups may covalently crosslink with the epoxy groups of the outer resin, forming a chemical bonding interface, thereby enhancing the interlayer bonding strength; at the same time, this intermediate layer can buffer the stress generated by the difference in thermal expansion coefficient between the aluminum substrate and the resin, reducing the interface microcracks, and avoiding the loss of antibacterial activity due to coating peeling.

[0046] Example 2 has obvious advantages in bacteriostatic rate and adhesion over Comparative Example 2. Comparative Example 2 uses unmodified zinc-aluminum layered double hydroxide, which has significantly weaker performance than the phenyl triazole modified carrier. This suggests that the introduction of phenyl triazole group has a dual effect on the system: on the one hand, the nitrogen atom in the triazole ring can act as a coordination site for silver ions, promoting uniform deposition and stable loading of silver nanoparticles, enhancing antibacterial activity; on the other hand, the aromatic ring structure of phenyl triazole may have π-π stacking with the aromatic components in the resin, improving the dispersion compatibility of the antibacterial agent in the resin, reducing interface defects, thereby enhancing the overall performance and durability of the coating.

[0047] The performance of Example 2 is better than that of Comparative Example 3, which replaces the benzene ring structure in phenyl triazole with a propyl chain. This difference indicates that the benzene ring structure has a key impact on the function of the material: the rigid structure of the aromatic ring may optimize the slow release effect of silver ions through steric hindrance, and at the same time, the π-π interaction between the benzene ring and the aromatic components in the resin can form an intermolecular physical crosslinking network, enhancing the interfacial bonding force between the antibacterial agent and the resin, avoiding the migration or shedding of the antibacterial components during heat aging, and maintaining long-term bacteriostatic ability.

[0048] Example 2 showed better antibacterial durability and adhesion stability than Comparative Example 4. The absence of bisphenol A type epoxy acrylate led to the performance of the coating to deteriorate more after heat aging, and it was speculated that the benzene ring structure played an important role in the resin system: the rigid aromatic chain of bisphenol A type epoxy acrylate could increase the glass transition temperature of the polymer, and enhance the thermal stability of the coating; the π-π stacking of the benzene ring with the phenyl triazole in the antibacterial agent could form secondary crosslinking points, and optimize the resin-antibacterial agent interfacial compatibility.

[0049] It should be understood by those of ordinary skill in the art that the above discussion of any of the embodiments is merely exemplary in nature and is not intended to suggest the scope of the application, which is limited solely by the claims; the technical features among the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above, which are not provided in details for the sake of brevity.

Claims

1. A bacterium-inhibiting aluminum foil material for a meal box, characterized by comprising: The aluminum foil is dipped in a sol impregnation solution and then dipped in an outer layer coating solution to obtain the coated aluminum foil; The sol impregnation solution comprises the following raw materials in parts by weight: 1-3 parts of tetraethyl orthosilicate, 0.3-0.8 parts of γ-aminopropyl triethoxysilane, 40-60 parts of anhydrous ethanol and 3-8 parts of deionized water; The outer layer coating solution comprises the following raw materials in parts by weight: 0.8-1.2 parts of hexafluorobutyl acrylate, 1.5-2.5 parts of glycidyl methacrylate, 2-4 parts of bisphenol A type epoxy acrylate, 0.05-0.15 parts of a photoinitiator, 0.4-0.6 parts of an antibacterial agent and 20-30 parts of acetone; The antibacterial agent is prepared by the following steps S1: γ-glycidyl ether propyltrimethoxysilane modified layered double hydroxide to obtain an epoxidized layered double hydroxide; S2: the epoxidized layered double hydroxide and propargylamine are subjected to an epoxy ring-opening reaction to obtain an alkynylated layered double hydroxide; S3: the alkynylated layered double hydroxide and azidobenzene are subjected to an azide-alkyne cycloaddition reaction under the catalysis of cuprous bromide and sodium ascorbate to obtain a phenyltriazole modified layered double hydroxide; S4: the phenyltriazole modified layered double hydroxide is loaded with silver nitrate and then reduced by ultraviolet radiation to obtain the antibacterial agent.

2. The antibacterial aluminum foil material for a meal box according to claim 1, characterized by The aluminum foil is subjected to surface activation treatment before being dipped in the sol impregnation solution, and the specific steps are as follows: the aluminum foil is sequentially dipped in acetone and anhydrous ethanol, subjected to ultrasonic treatment and then subjected to plasma activation treatment.

3. The antibacterial aluminum foil material for a meal box according to claim 1, characterized by The pulling rate of the dipping and pulling coating in the sol impregnation solution is 80-120 mm / min, and the pulling times are 2-4 times; the pulling rate of the dipping and pulling coating in the outer layer coating solution is 40-60 mm / min, and the pulling times are 2-4 times.

4. The bacterium-inhibiting aluminum foil material for a meal box according to claim 1, characterized by The weight ratio of the γ-glycidyl ether propyltrimethoxysilane to the layered double hydroxide in step S1 is 0.2-0.4:0.4-0.6; the layered double hydroxide in step S1 is zinc-aluminum layered double hydroxide with a Zn / Al molar ratio of 2:1 and a flake diameter of 1-4 μm.

5. The bacterium-inhibiting aluminum foil material for a meal box according to claim 1, characterized by The weight ratio of the epoxidized layered double hydroxide to propargylamine in step S2 is 0.4-0.6:0.15-0.

25.

6. The bacterium-inhibiting aluminum foil material for a meal box according to claim 1, characterized by The weight ratio of the alkynylated layered double hydroxide, azidobenzene, cuprous bromide and sodium ascorbate in step S3 is 0.4-0.6:0.2-0.3:0.04-0.06:0.12-0.

18.

7. The bacterium-inhibiting aluminum foil material for a meal box according to claim 1, characterized by The weight ratio of the phenyltriazole modified layered double hydroxide to silver nitrate in step S4 is 0.4-0.6:0.016-0.

024.

8. The bacterium-inhibiting aluminum foil material for a meal box according to claim 1, characterized by The radiation intensity of the UV radiation reduction in step S4 is 30-50 mW / cm 2 , the time is 10-14 min, and the wavelength is 254 nm.

9. A method of producing the bacterium-inhibiting aluminum foil material for a meal box according to any one of claims 1 to 8, characterized by, The method comprises the following steps: (1) tetraethyl orthosilicate and γ-aminopropyl triethoxysilane are added to a mixed solution of anhydrous ethanol and deionized water, stirred at room temperature for 8-12 min, the pH is adjusted to 9.1-9.3 with ammonia water, and the stirring is continued for 20-40 min to obtain a sol impregnation solution; the surface-activated aluminum foil is dipped in the sol impregnation solution in a vertical direction to perform dipping and pulling coating, and after the pulling is completed, the coated aluminum foil is dried to obtain an aminated organosilicon coated aluminum foil; (2) The hexafluorobutyl acrylate, glycidyl methacrylate, bisphenol A type epoxy acrylate, photoinitiator and antibacterial agent are added into acetone, and ultrasonic treatment is carried out for 20-40 min to obtain an outer coating solution; the amino-organosilicon coated aluminum foil is immersed into the outer coating solution in a vertical direction, and dip-coating is carried out; after the dip-coating is completed, drying, ultraviolet radiation curing are carried out, and an antibacterial aluminum foil material for a meal box is obtained.

10. The method for preparing antibacterial aluminum foil material for lunch boxes according to claim 9, characterized in that, The radiation intensity of the ultraviolet radiation curing in the step (2) is 80-120 mW / cm 2 , the time is 80-100 seconds, and the wavelength is 365 nm.