Preparation method and application of aluminum foil packaging material

Abstract

The invention provides a preparation method and application of an aluminum foil packaging material, and relates to the technical field of aluminum foil packaging, and the method comprises the following steps: preparing a core layer casting plate, a barrier layer casting plate and a functional layer casting plate; sequentially stacking the core layer casting plate, the barrier layer casting plate and the functional layer casting plate to prepare a composite aluminum foil plate, carrying out hot rolling on the composite aluminum foil plate, then carrying out a preliminary aluminum foil optimal thickness determination test to determine the preliminary aluminum foil optimal thickness, and carrying out cold rolling treatment to form a preliminary aluminum foil; and carrying out surface modification on the primary aluminum foil, and spraying an antibacterial coating to form the finished aluminum foil. Through the three-layer structural design, the core layer provides basic strength, the blocking layer provides aluminum foil blocking performance including water vapor blocking performance and oxygen blocking performance, the functional layer provides antibacterial, light blocking and water vapor blocking functions, the blocking performance of traditional aluminum foil is improved, permeation of water vapor, oxygen and light is effectively blocked, and the service life of the aluminum foil is prolonged. The packaging box is used for packaging freeze-dried products, and it is guaranteed that the freeze-dried products are not prone to getting damp in aluminum foil materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum foil packaging, and particularly relates to a preparation method and application of an aluminum foil packaging material. Background Art

[0002] Due to its high barrier property, aluminum can effectively isolate oxygen, moisture and light, which is very important for the preservation of food and medicine. At the same time, due to its good ductility, it is easy to be processed into different shapes and thicknesses to meet various packaging requirements. Therefore, aluminum foil has become the core material in the high-end packaging field with its unique physical and chemical properties;

[0003] Freeze-dried foods (such as high-end ingredients like matsutake) have become an important category in the field of healthy foods because they retain their original nutritional components and flavor characteristics through low-temperature dehydration technology. Although traditional freeze-drying technology can reduce the water content to less than 1%, it faces the problem of water return during storage due to environmental humidity, oxygen penetration and light. When the water content rises to more than 3%, the product is prone to browning, aroma dissipation and texture softening, resulting in deterioration of color, aroma and taste. Traditional processes mostly use single-layer homogeneous aluminum rolling, with insufficient barrier performance and inability to effectively isolate the penetration of water vapor, oxygen and light, making it difficult to meet the packaging requirements of high-end freeze-dried foods. Moreover, conventional aluminum foil preparation processes cannot carry out targeted customization production of aluminum foil based on the actual usage requirements of the packaged products, resulting in insufficient adaptability. Summary of the Invention

[0004] The present invention provides a preparation method and application of an aluminum foil packaging material to solve at least one of the above-mentioned technical problems.

[0005] To solve the above technical problems, the present invention discloses a preparation method and application of an aluminum foil packaging material. The method includes the following steps:

[0006] S1. Prepare a core layer ingot, a barrier layer ingot and a functional layer ingot, and respectively perform hot rolling on the core layer ingot, the barrier layer ingot and the functional layer ingot to form a core layer plate, a barrier layer plate and a functional layer plate;

[0007] S2. Stack the core layer plate, the barrier layer plate and the functional layer plate in sequence, fix them with a fixture, and then put them into an annealing furnace so that the core layer plate, the barrier layer plate and the functional layer plate are combined into one body to form a composite aluminum foil plate. Perform hot rolling on the composite aluminum foil plate. After the hot rolling is completed, conduct a preliminary test on the optimal thickness of the aluminum foil, determine the preliminary optimal thickness of the aluminum foil based on the test results, and perform cold rolling treatment based on the preliminary optimal thickness of the aluminum foil to finally form a preliminary aluminum foil;

[0008] The preliminary aluminum foil includes a core layer, a barrier layer, and a functional layer. The core layer is used to provide basic strength, the barrier layer is used to provide the barrier performance of the aluminum foil, including water vapor barrier performance and oxygen barrier performance, and the functional layer is used to provide antibacterial, light barrier, and water vapor barrier functions;

[0009] S3. Use a plasma processing device to perform surface modification on the preliminary aluminum foil, and spray an antibacterial coating on the surface of the surface-modified preliminary aluminum foil;

[0010] S4. Anneal the preliminary aluminum foil sprayed with the antibacterial coating to form the finished aluminum foil. Take samples from each batch of the finished aluminum foil for quality inspection. After passing the quality inspection, cut and package it.

[0011] Preferably, step S1 includes the following steps:

[0012] S11. Add the raw materials of the aluminum foil core layer, the barrier layer, and the functional layer to the melting furnace for melting according to the component ratios. The melting temperatures of the raw materials of the aluminum foil core layer, the barrier layer, and the functional layer are 700 - 800 °C, 700 - 750 °C, and 750 - 800 °C respectively;

[0013] S12. Pour the molten raw materials of the core layer, the barrier layer, and the functional layer into a die casting machine for cooling to form a core layer ingot, a barrier layer ingot, and a functional layer ingot;

[0014] S13. Put the core layer ingot, the barrier layer ingot, and the functional layer ingot into a sawing machine for cutting, and mill the cutting surface to ensure the surface is flat;

[0015] S14. Put the cut core layer ingot, barrier layer ingot, and functional layer ingot into an annealing furnace for homogenization treatment;

[0016] S15. Hot-roll the core layer ingot, barrier layer ingot, and functional layer ingot after homogenization treatment to form a core layer casting plate, a barrier layer casting plate, and a functional layer casting plate. The hot-rolling temperature is 400 - 450 °C.

[0017] Preferably, the component ratio of the core layer raw materials: aluminum 99.3%, iron 0.1%, copper 0.1%, magnesium 0.15%, zirconium 0.05%, silicon 0.1%, titanium 0.1%, graphene oxide 0.05%, carbon nanotubes 0.05%;

[0018] The component ratio of the barrier layer raw materials: aluminum 99%, iron 0.05%, copper 0.05%, magnesium 0.05%, silicon 0.05%, titanium 0.05%, chromium 0.2%, yttrium 0.1%, tin 0.1%, nano-silica 0.3%, graphene 0.05%;

[0019] Functional layer raw material composition ratio: aluminum 99.1%, iron 0.05%, copper 0.03%, magnesium 0.02%, silicon 0.05%, titanium 0.05%, polyvinylidene chloride 0.3%, ethylene-vinyl alcohol copolymer 0.2%, silver-zinc composite nanoparticles 0.1%, titanium dioxide nanotubes 0.1%.

[0020] Preferably, the thicknesses of the core layer casting plate, the barrier layer casting plate, and the functional layer casting plate are 10-20 mm, 8-15 mm, and 10-18 mm respectively;

[0021] The thickness of the hot-rolled composite aluminum foil plate is 8-10 mm.

[0022] Preferably, after hot rolling, a preliminary test for determining the optimal thickness of the aluminum foil is carried out, and the preliminary optimal thickness of the aluminum foil is determined based on the test results, including:

[0023] S21. Cold-roll the hot-rolled composite aluminum foil plate at different cold rolling reduction rates to prepare several cold-rolled samples, measure the thickness of each cold-rolled sample, and record the thickness values;

[0024] S22. Prepare each cold-rolled sample into a standard specimen according to the standard requirements of the tensile test, and use a universal material testing machine to conduct a tensile test on each cold-rolled sample, and record the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test;

[0025] S23. Generate a corresponding performance matrix based on the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test. Based on the performance matrix of each cold-rolled sample and the preset performance matrix, determine three alternative thicknesses, customize three cold-rolled samples based on the alternative thicknesses, and conduct a barrier property test on the cold-rolled samples, and determine the preliminary optimal thickness of the aluminum foil based on the test results of the barrier property test.

[0026] Preferably, step S23 includes:

[0027] S231. Generate a tensile strength curve, a yield strength curve, and an elongation curve based on the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test;

[0028] S232. Extract the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve, generate a tensile strength eigenvector, a yield strength eigenvector, and an elongation eigenvector based on the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve, and generate a performance matrix of the corresponding cold-rolled sample based on the tensile strength eigenvector, the yield strength eigenvector, and the elongation eigenvector;

[0029] S233. Calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix, and take the thicknesses corresponding to the top three cold-rolled samples in terms of the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix as alternative thicknesses. Customize three cold-rolled samples based on the alternative thicknesses, conduct a barrier property test on the cold-rolled samples, and select the alternative thickness corresponding to the cold-rolled sample with the best barrier property as the preliminary optimal thickness of the aluminum foil.

[0030] Preferably, calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix:

[0031] Among them, is the proximity between the performance matrix corresponding to the kth cold-rolled sample and the preset performance matrix, x kij is the value at the i-th row and j-th column in the performance matrix corresponding to the kth cold-rolled sample, x 0ij is the value at the i-th row and j-th column in the preset performance matrix, a is the total number of rows of the performance matrix, and b is the total number of columns of the performance matrix.

[0032] Preferably, step S3 includes:

[0033] S31. Put the preliminary aluminum foil into a plasma treatment device, set the gas type as argon or nitrogen, and the treatment time as 30 seconds to 1 minute to improve the surface activity;

[0034] S32. Use a spraying device to evenly spray the antibacterial coating on the surface of the preliminary aluminum foil, and control the coating thickness within 0.001 - 0.002 mm, where the antibacterial coating uses silver nanoparticles.

[0035] Preferably, during the preparation process of each batch of aluminum foil packaging materials, during each hot rolling or cold rolling step completion, sampling thickness detection is required to accept the current hot rolling or cold rolling result. The steps are as follows:

[0036] Step 1. Extract m hot-rolled or cold-rolled products after completion from the products after the current hot rolling or cold rolling for thickness detection. The thickness detection step is to evenly divide each hot-rolled or cold-rolled product after completion into j detection segments along the length direction, take the midpoint of each detection segment for thickness detection, and obtain the thickness value at the midpoint of each detection segment;

[0037] Step 2. Based on the thickness values at the midpoints of each detection segment of the m hot-rolled or cold-rolled products after completion, calculate the thickness qualification evaluation value of the products after the current hot rolling or cold rolling:

[0038] Among them, W is the evaluation value of the thickness qualification of the product after current hot rolling or cold rolling, m is the total number of thickness detection samples in the product after current hot rolling or cold rolling, ξ1 is the influence coefficient of thickness accuracy on thickness qualification, n is the number of detection segments of the product after hot rolling or cold rolling, H ij is the thickness value at the midpoint of the j-th detection segment in the i-th sampled product after hot rolling or cold rolling, H0 is the preset thickness value of the product after current hot rolling or cold rolling, and ξ2 is the influence coefficient of thickness uniformity on thickness qualification;

[0039] If the evaluation value of the thickness qualification of the product after current hot rolling or cold rolling is greater than the reference thickness qualification evaluation value, it proves that the current preparation step passes the acceptance. Otherwise, it proves that the current preparation step fails the acceptance, and an alarm prompt is given to check and adjust the preparation equipment or preparation method in time.

[0040] Preferably, the quality inspection of the finished aluminum foil in step S4 includes appearance evaluation, performance evaluation, and size qualification evaluation;

[0041] Among them, the appearance evaluation includes sampling the surface smoothness evaluation of each batch of finished aluminum foil by using an image acquisition device and a trained aluminum foil surface smoothness evaluation model to obtain the surface smoothness evaluation value of each batch of finished aluminum foil;

[0042] The performance evaluation includes sampling the antibacterial performance, barrier performance, and mechanical performance quality inspection tests on each batch of finished aluminum foil to obtain the antibacterial performance evaluation value, barrier performance evaluation value, and mechanical performance evaluation value of each batch of finished aluminum foil;

[0043] The size qualification evaluation includes sampling the thickness detection of each batch of finished aluminum foil and calculating the size qualification evaluation value of the current batch of finished aluminum foil based on the thickness detection results;

[0044] Based on the surface smoothness evaluation value, antibacterial performance evaluation value, barrier performance evaluation value, mechanical performance evaluation value, and size qualification evaluation value of each batch of finished aluminum foil, the comprehensive performance evaluation value of each batch of finished aluminum foil is obtained, and the quality inspection result is generated based on the comprehensive performance evaluation value of each batch of finished aluminum foil;

[0045] Among them, the comprehensive performance evaluation value of each batch of finished aluminum foil:

[0046] Among them, ∈ is the comprehensive performance evaluation value of the current batch of finished aluminum foil, Z αβ is the α-th evaluation value corresponding to the β-th sample in the current batch of finished aluminum foil, γ α is the weight of the α-th evaluation value, and y is the total number of samples of the current batch of finished aluminum foil.

[0047] An application of an aluminum foil packaging material, and the prepared aluminum foil packaging material is used for packaging freeze-dried products.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) Through a three-layer structure design, the core layer provides basic strength, the barrier layer provides the barrier properties of aluminum foil, including water vapor barrier property and oxygen barrier property, and the functional layer provides antibacterial, light barrier and water vapor barrier functions, greatly improving the barrier property of traditional aluminum foil, effectively blocking the penetration of water vapor, oxygen and light, capable of controlling the water content of the product below 3% and extending the product storage time by more than 5 times, meeting the packaging requirements of high-end ingredients such as matsutake, retaining the original nutritional components and flavor characteristics of high-end ingredients. By conducting an experiment to determine the preliminary optimal thickness of aluminum foil, it avoids the situation that the fluctuation of the finished product thickness often leads to insufficient utilization rate of aluminum foil materials, resulting in waste of resources or insufficient performance affecting the packaging effect, and can determine the optimal thickness of aluminum foil based on actual needs to achieve flexible customization of aluminum foil, ensuring product performance while saving costs to the greatest extent. The antibacterial coating uses silver nanoparticles, effectively inhibiting the growth of microorganisms and extending the service life of aluminum foil. Each batch of finished aluminum foil is sampled for quality inspection to ensure the ex-factory quality of the product;

[0050] (2) The core layer of the present invention provides basic strength, the barrier layer enhances the barrier property, and the functional layer adds antibacterial function. Materials such as nano-silica and polyethylene have good environmental adaptability, and silver nanoparticles have high antibacterial ability, extending the service life of aluminum foil. The addition of various trace elements improves the corrosion resistance and oxidation resistance of the materials;

[0051] (3) The present invention cold-rolls the hot-rolled composite aluminum foil sheet according to different cold-rolling reduction ratios to prepare several cold-rolled samples, conducts tensile tests on the cold-rolled samples, records the data of tensile strength, yield strength and elongation, generates tensile strength curves, yield strength curves and elongation curves based on the test data, and extracts key characteristic values to generate a performance matrix. Detailed performance data are obtained through tensile tests to ensure accurate results. By calculating the proximity between the performance matrix and the preset performance matrix, three alternative thicknesses are determined. Three cold-rolled samples are customized based on the alternative thicknesses, and barrier property tests are conducted on the cold-rolled samples. The optimal thickness of aluminum foil is determined based on the test results of the barrier property tests, which can quickly determine the optimal thickness, avoiding the situation that the fluctuation of the finished product thickness often leads to insufficient utilization rate of aluminum foil materials, resulting in waste of resources or insufficient performance affecting the packaging effect, and realizing the flexible customization of aluminum foil;

[0052] (4) The present invention realizes the acceptance of the qualification of the current preparation step by accepting the current hot-rolling or cold-rolling results, can accurately locate the links where errors occur in the preparation process, can minimize the losses caused by improper operation, realizes the timely inspection and adjustment of the preparation equipment or preparation method, and helps to improve product quality. Description of the Drawings

[0053] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the accompanying drawings:

[0054] Figure 1 It is a schematic diagram of the preparation method of the aluminum foil packaging material of the present invention. Detailed embodiments

[0055] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0056] In addition, in the present invention, descriptions such as "first" and "second" are only for descriptive purposes and do not particularly refer to the meaning of order or sequence. Nor are they used to limit the present invention. They are merely used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions and technical features between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0057] The present invention provides the following embodiments

[0058] Embodiment 1

[0059] The embodiment of the present invention provides a preparation method and application of an aluminum foil packaging material, as Figure 1 shown. The method includes the following steps:

[0060] S1. Prepare a core layer ingot, a barrier layer ingot, and a functional layer ingot, and respectively perform hot rolling on the core layer ingot, the barrier layer ingot, and the functional layer ingot to form a core layer casting plate, a barrier layer casting plate, and a functional layer casting plate;

[0061] S2. Stack the core layer casting plate, the barrier layer casting plate, and the functional layer casting plate in sequence, fix them with a clamp, and then put them into an annealing furnace so that the core layer casting plate, the barrier layer casting plate, and the functional layer casting plate are combined into one body to form a composite aluminum foil plate. Perform hot rolling on the composite aluminum foil plate. After the hot rolling is completed, conduct a preliminary test for determining the optimal thickness of the aluminum foil. Based on the test results, determine the preliminary optimal thickness of the aluminum foil, and perform cold rolling treatment based on the preliminary optimal thickness of the aluminum foil to finally form a preliminary aluminum foil;

[0062] The preliminary aluminum foil includes a core layer, a barrier layer, and a functional layer. The core layer is used to provide basic strength, the barrier layer is used to provide the barrier performance of the aluminum foil, including water vapor barrier performance and oxygen barrier performance, and the functional layer is used to provide antibacterial, light barrier, and water vapor barrier functions;

[0063] S3. Use a plasma processing device to perform surface modification on the preliminary aluminum foil, and spray an antibacterial coating on the surface of the surface-modified preliminary aluminum foil;

[0064] S4. Anneal the preliminary aluminum foil sprayed with the antibacterial coating to form the finished aluminum foil. Take samples from each batch of the finished aluminum foil for quality inspection. After passing the quality inspection, cut and package it.

[0065] Preferably, the thicknesses of the core layer casting plate, the barrier layer casting plate, and the functional layer casting plate are 10 - 20 mm, 8 - 15 mm, and 10 - 18 mm respectively;

[0066] The thickness of the hot-rolled composite aluminum foil plate is 8 - 10 mm.

[0067] The working principle and beneficial effects of the above technical solution are as follows: In the present invention, ingots are formed by melting raw materials with different components, and through cutting, milling, homogenization treatment, and hot rolling, three-layer casting plates (core layer casting plate, barrier layer casting plate, and functional layer casting plate) are formed. Stack the three-layer casting plates and hot roll them to form a composite aluminum foil plate. Then, determine the optimal thickness of the preliminary aluminum foil through the test of the optimal thickness of the preliminary aluminum foil. Based on the optimal thickness of the preliminary aluminum foil, perform cold rolling treatment to finally form the preliminary aluminum foil. Use a plasma processing device to modify the surface of the preliminary aluminum foil, and spray an antibacterial coating. Anneal the preliminary aluminum foil sprayed with the antibacterial coating, ensure the quality through sampling quality inspection, and finally cut and package;

[0068] Through the three-layer structure design of the present invention, the core layer provides basic strength, the barrier layer provides the barrier performance of the aluminum foil, including water vapor barrier performance and oxygen barrier performance, and the functional layer provides antibacterial, light barrier, and water vapor barrier functions, greatly improving the barrier property of traditional aluminum foil, effectively blocking the penetration of water vapor, oxygen, and light, meeting the packaging requirements of high-end food such as matsutake, retaining the original nutritional components and flavor characteristics of high-end food. Determine the optimal thickness of the preliminary aluminum foil through the test of the optimal thickness of the preliminary aluminum foil, avoiding the situation that the fluctuation of the finished product thickness often leads to insufficient utilization rate of aluminum foil materials, resulting in waste of resources or insufficient performance affecting the packaging effect. It can determine the optimal thickness of the aluminum foil based on actual needs to achieve flexible customization of the aluminum foil, ensuring product performance while maximizing cost savings. The antibacterial coating uses silver nanoparticles, effectively inhibiting the growth of microorganisms and extending the service life of the aluminum foil. Each batch of the finished aluminum foil is sampled for quality inspection to ensure the ex-factory quality of the product.

[0069] Example 2

[0070] Based on Example 1, step S1 includes the following steps:

[0071] S11. Add the aluminum foil core layer raw material, barrier layer raw material, and functional layer raw material to the melting furnace for melting according to the component ratios respectively. The melting temperatures of the aluminum foil core layer raw material, barrier layer raw material, and functional layer raw material are 700 - 800 °C, 700 - 750 °C, and 750 - 800 °C respectively;

[0072] S12. Pour the melted core layer raw material, barrier layer raw material, and functional layer raw material into a die casting machine for cooling respectively to form a core layer ingot, a barrier layer ingot, and a functional layer ingot;

[0073] S13. Put the core layer ingot, barrier layer ingot, and functional layer ingot into a sawing machine for cutting, and perform milling on the cutting surface to ensure a flat surface;

[0074] S14. Put the cut core layer ingot, barrier layer ingot, and functional layer ingot into an annealing furnace for homogenization treatment;

[0075] S15. Perform hot rolling on the homogenized core layer ingot, barrier layer ingot, and functional layer ingot to form a core layer casting plate, a barrier layer casting plate, and a functional layer casting plate. The hot rolling temperature is 400 - 450 °C.

[0076] Preferably, the component ratio of the core layer raw material: aluminum 99.3%, iron 0.1%, copper 0.1%, magnesium 0.15%, zirconium 0.05%, silicon 0.1%, titanium 0.1%, graphene oxide 0.05%, carbon nanotubes 0.05%;

[0077] The component ratio of the barrier layer raw material: aluminum 99%, iron 0.05%, copper 0.05%, magnesium 0.05%, silicon 0.05%, titanium 0.05%, chromium 0.2%, yttrium 0.1%, tin 0.1%, nano - silica 0.3%, graphene 0.05%;

[0078] The component ratio of the functional layer raw material: aluminum 99.1%, iron 0.05%, copper 0.03%, magnesium 0.02%, silicon 0.05%, titanium 0.05%, polyvinylidene chloride 0.3%, ethylene - vinyl alcohol copolymer 0.2%, silver - zinc composite nanoparticles 0.1%, titanium dioxide nanotubes 0.1%.

[0079] The working principle and beneficial effects of the above - mentioned technical solution are as follows: By precisely controlling the melting temperature and component ratios, the present invention ensures the quality of the properties of each layer of materials. Cutting and milling treatments ensure a flat surface, avoiding subsequent processing defects. Homogenization treatment eliminates internal stress and improves the consistency of material properties. The hot rolling temperature is appropriate, which can not only ensure the plasticity of the material but also improve production efficiency;

[0080] The core layer of the present invention provides basic strength (0.05% of graphene oxide and 0.05% of carbon nanotubes can enhance the bonding force between the core layer and the barrier layer and improve the mechanical strength of the aluminum foil, and 0.15% of magnesium and 0.05% of zirconium can improve the corrosion resistance and service life of the aluminum foil), the barrier layer enhances the barrier performance (0.3% of nano-silica can reduce the water vapor transmission rate, 0.2% of chromium and 0.1% of yttrium can increase the oxygen barrier property, and 0.05% of graphene can form a hydrophobic surface to reduce water adsorption), and the functional layer increases the antibacterial and light barrier functions (0.1% of silver-zinc composite nanoparticles has antibacterial effect, 0.3% of polyvinylidene chloride and 0.2% of ethylene-vinyl alcohol copolymer have the functions of blocking water vapor and oxygen, and 0.1% of titanium dioxide nanotubes can block ultraviolet rays;

[0081] Through the three-layer structure design, the present invention can control the water content of high-end food materials such as matsutake below 3%, extend the storage time of high-end food materials such as matsutake by more than 5 times, and retain the original nutritional components and flavor characteristics of high-end food materials.

[0082] Example 3

[0083] On the basis of Example 1, after hot rolling, a test for determining the optimal thickness of the preliminary aluminum foil is carried out, and the optimal thickness of the preliminary aluminum foil is determined based on the test results, including:

[0084] S21. Cold roll the hot-rolled composite aluminum foil sheet at different cold rolling reduction rates to prepare a number of cold-rolled samples, measure the thickness of each cold-rolled sample, and record the thickness values;

[0085] S22. Prepare each cold-rolled sample into a standard specimen according to the standard requirements of the tensile test, and use a universal material testing machine to conduct a tensile test on each cold-rolled sample, and record the tensile strength, yield strength and elongation data of the cold-rolled sample during the test;

[0086] S23. Generate a corresponding performance matrix based on the tensile strength, yield strength and elongation data of the cold-rolled sample during the test. Based on the performance matrix of each cold-rolled sample and the preset performance matrix, determine three alternative thicknesses, customize three cold-rolled samples based on the alternative thicknesses, conduct a barrier property test on the cold-rolled samples, and determine the optimal thickness of the preliminary aluminum foil based on the test results of the barrier property test.

[0087] The working principle and beneficial effects of the above technical solution are as follows: The present invention subjects the hot-rolled composite aluminum foil sheet to cold rolling treatment at different cold rolling reduction rates to prepare a number of cold-rolled samples. Each cold-rolled sample is prepared into a standard specimen according to the standard requirements of the tensile test, that is, the dimensions of each cold-rolled sample except for the thickness are unified, and the tensile strength, yield strength, and elongation data of the cold-rolled samples during the test are recorded. Among them, the tensile strength can reflect the material strength of the aluminum foil during product packaging, and the yield strength and elongation can reflect the material shape adaptability of the aluminum foil during product packaging. The preset performance matrix is a matrix customized based on the required packaging performance of the product to be packaged;

[0088] The present invention subjects the hot-rolled composite aluminum foil sheet to cold rolling at different cold rolling reduction rates to prepare a number of cold-rolled samples, conducts a tensile test on the cold-rolled samples, records the tensile strength, yield strength, and elongation data, generates a tensile strength curve, a yield strength curve, and an elongation curve based on the test data, extracts key characteristic values to generate a performance matrix, obtains detailed performance data through the tensile test to ensure accurate results, determines three alternative thicknesses through the proximity calculation between the performance matrix and the preset performance matrix (the packaging performance matrix designed based on the product to be packaged), customizes three cold-rolled samples based on the alternative thicknesses, conducts a barrier property test on the cold-rolled samples, and determines the optimal thickness of the aluminum foil based on the test results of the barrier property test. It can quickly determine the optimal thickness, avoiding the situation where the insufficient utilization rate of aluminum foil materials caused by the thickness fluctuation of the finished product often leads to resource waste or insufficient performance affecting the packaging effect, and realizing the flexible customization of aluminum foil.

[0089] Example 4

[0090] On the basis of Example 3, step S23 includes:

[0091] S231. Generate a tensile strength curve, a yield strength curve, and an elongation curve based on the tensile strength, yield strength, and elongation data of the cold-rolled samples during the test;

[0092] S232. Extract the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve, generate a tensile strength eigenvector, a yield strength eigenvector, and an elongation eigenvector based on the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve, and generate a performance matrix of the corresponding cold-rolled sample based on the tensile strength eigenvector, the yield strength eigenvector, and the elongation eigenvector;

[0093] S233. Calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix, take the thicknesses corresponding to the three cold-rolled samples with the top three proximity between the performance matrix of the cold-rolled sample and the preset performance matrix as alternative thicknesses, customize three cold-rolled samples based on the alternative thicknesses, conduct a barrier property test on the cold-rolled samples, and select the alternative thickness corresponding to the cold-rolled sample with the best barrier property as the preliminary optimal thickness of the aluminum foil;

[0094] Calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix:

[0095] Wherein, is the proximity between the performance matrix corresponding to the k-th cold-rolled sample and the preset performance matrix, x kij is the value at the i-th row and j-th column in the performance matrix corresponding to the k-th cold-rolled sample, x 0ij is the value at the i-th row and j-th column in the preset performance matrix, a is the total number of rows of the performance matrix, and b is the total number of columns of the performance matrix.

[0096] The working principle and beneficial effects of the above technical solution: The present invention generates tensile strength curves, yield strength curves, and elongation curves based on test data, extracts key characteristic values of the curves (including the maximum value, average value, and inflection point position of the tensile strength curve, yield strength curve, and elongation curve) to generate characteristic vectors, generates a performance matrix based on the characteristic vectors, and determines the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix. The thicknesses corresponding to the top three cold-rolled samples are used as alternative thicknesses, and three cold-rolled samples are customized based on the alternative thicknesses. Then, a barrier property test is performed on the cold-rolled samples, and the alternative thickness corresponding to the cold-rolled sample with the best barrier property is selected as the preliminary best thickness of the aluminum foil. Here, the barrier property is mainly judged based on the water vapor barrier property, so that the aluminum foil can be precisely customized based on the actual usage requirements of the specific product to be packaged;

[0097] When calculating the proximity between the performance matrix corresponding to the cold-rolled sample and the preset performance matrix, the present invention takes into account each element in the matrix, thus ensuring the accuracy of the calculation result.

[0098] Example 5

[0099] Based on Example 1, step S3 includes:

[0100] S31. Place the preliminary aluminum foil in a plasma treatment device, set the gas type to argon or nitrogen, and the treatment time to 30 seconds to 1 minute to improve the surface activity;

[0101] S32. Use a spraying device to evenly spray an antibacterial coating on the surface of the preliminary aluminum foil, and control the coating thickness within 0.001 - 0.002 mm, where the antibacterial coating uses silver nanoparticles.

[0102] The working principle and beneficial effects of the above technical solution are: The plasma treatment of the present invention improves the surface activity and enhances the coating adhesion. Silver nanoparticles have high antibacterial ability, and the spraying device can ensure uniform distribution of the coating, thus improving the packaging performance of the aluminum foil.

[0103] Example 6

[0104] Based on Example 1, during the preparation process of each batch of aluminum foil packaging materials, sampling thickness detection shall be carried out at the end of each hot rolling or cold rolling step to accept the current hot rolling or cold rolling results. The steps are as follows:

[0105] Step 1: Extract m products after hot rolling or cold rolling from the products after the current hot rolling or cold rolling is completed for thickness detection. The thickness detection step is to evenly divide each product after hot rolling or cold rolling into j detection segments along the length direction, take the midpoint of each detection segment for thickness detection, and obtain the thickness value at the midpoint of each detection segment;

[0106] Step 2: Based on the thickness values at the midpoints of each detection segment of m products after hot rolling or cold rolling, calculate the thickness qualification evaluation value of the product after the current hot rolling or cold rolling is completed:

[0107] where W is the thickness qualification evaluation value of the product after the current hot rolling or cold rolling is completed, m is the total number of thickness detection samples in the product after the current hot rolling or cold rolling is completed, ξ1 is the influence coefficient of thickness accuracy on thickness qualification, n is the number of detection segments of the product after hot rolling or cold rolling, H ij is the thickness value at the midpoint of the j-th detection segment of the i-th sampled product after hot rolling or cold rolling, H0 is the preset thickness value of the product after the current hot rolling or cold rolling is completed, and ξ2 is the influence coefficient of thickness uniformity on thickness qualification;

[0108] If the thickness qualification evaluation value of the product after the current hot rolling or cold rolling is completed is greater than the reference thickness qualification evaluation value, it proves that the current preparation step passes the acceptance; otherwise, it proves that the current preparation step fails the acceptance, and an alarm prompt shall be given to promptly check and adjust the preparation equipment or preparation method.

[0109] The working principle and beneficial effects of the above technical solution are as follows: In the present invention, m products after hot rolling or cold rolling are extracted from the products after the current hot rolling or cold rolling is completed for thickness detection. The thickness detection step is to evenly divide each product after hot rolling or cold rolling into j detection segments along the length direction, take the midpoint of each detection segment for thickness detection, and obtain the thickness value at the midpoint of each detection segment. The extraction of multiple samples and the measurement of all detection segments ensure the accuracy of the calculation results. At the same time, when calculating the thickness qualification evaluation value of the product after the current hot rolling or cold rolling is completed, not only the accuracy of the thickness of the product after the current hot rolling or cold rolling is considered but also the uniformity of the thickness of the product after the current hot rolling or cold rolling is considered Thus, the acceptance of the current preparation step is realized from multiple aspects;

[0110] The present invention realizes the acceptance of the qualification of the current preparation step by accepting the results of current hot rolling or cold rolling. Acceptance after each hot rolling or cold rolling can accurately locate the links where errors occur in the preparation process, minimize production losses caused by improper operation, realize the timely troubleshooting and adjustment of the preparation equipment or method, and contribute to improving product quality and ensuring the stability of production quality.

[0111] Example 7

[0112] On the basis of Example 1, the quality inspection of the finished aluminum foil in step S4 includes appearance evaluation, performance evaluation, and dimensional qualification evaluation;

[0113] Among them, the appearance evaluation includes sampling the surface smoothness evaluation of each batch of finished aluminum foil using an image acquisition device and a trained aluminum foil surface smoothness evaluation model to obtain the surface smoothness evaluation value of each batch of finished aluminum foil;

[0114] The performance evaluation includes sampling antibacterial performance, barrier performance, and mechanical performance quality inspection tests on each batch of finished aluminum foil to obtain the antibacterial performance evaluation value, barrier performance evaluation value, and mechanical performance evaluation value of each batch of finished aluminum foil;

[0115] The dimensional qualification evaluation includes sampling the thickness detection of each batch of finished aluminum foil and calculating the dimensional qualification evaluation value of the current batch of finished aluminum foil based on the thickness detection results;

[0116] Based on the surface smoothness evaluation value, antibacterial performance evaluation value, barrier performance evaluation value, mechanical performance evaluation value, and dimensional qualification evaluation value of each batch of finished aluminum foil, the comprehensive performance evaluation value of each batch of finished aluminum foil is obtained, and the quality inspection result is generated based on the comprehensive performance evaluation value of each batch of finished aluminum foil;

[0117] Among them, the comprehensive performance evaluation value of each batch of finished aluminum foil:

[0118] Among them, ∈ is the comprehensive performance evaluation value of the current batch of finished aluminum foil, Z αβ is the α-th evaluation value corresponding to the β-th sample in the current batch of finished aluminum foil, γ α is the weight of the α-th evaluation value, and y is the total number of samples of the current batch of finished aluminum foil.

[0119] Preferably, the antibacterial performance quality inspection test:

[0120] Cut 5 specimens of 100 mm × 100 mm from the finished aluminum foil, clean them with ethanol, and sterilize them with ultraviolet light for 30 minutes;

[0121] Dilute the bacterial suspension (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC6538) with 0.85% NaCl solution, and adjust the concentration to 1×10 6CFU / mL;

[0122] Add 20 μL of the bacterial suspension dropwise onto the surface of the specimen, cover it with a polyethylene film (40 mm × 40 mm) to prevent evaporation. For the control group, use sterile aluminum foil, and for the experimental group, use the aluminum foil of the present invention. After culturing at 37 °C for 24 hours, count the number of colonies in the experimental group and the control group, calculate the antibacterial performance evaluation value, and take the antibacterial performance evaluation values of 5 specimens as the antibacterial performance evaluation value of the finished aluminum foil of the current batch.

[0123] Preferably, the barrier property quality inspection test includes an oxygen barrier property test and a water vapor barrier property test:

[0124] Oxygen barrier property test:

[0125] Cut out 3 circular specimens with a diameter of 100 mm. At 23 °C, clamp the circular specimens between two cups and seal the gap between the two cups. Fill one cup with oxygen and the other cup with nitrogen to ensure that the air pressures on both sides of the circular specimen are balanced. Record the oxygen permeation amount within a preset time, and calculate the oxygen barrier property evaluation value based on the oxygen permeation amount. The average value of the oxygen barrier property evaluation values of 3 circular specimens is used as the oxygen barrier property evaluation value of the finished aluminum foil of the current batch.

[0126] For the water vapor barrier property test, replace the oxygen and nitrogen in the above test with water vapor and nitrogen.

[0127] Preferably, the mechanical property quality inspection test:

[0128] Take several specimens for a tensile test, record the data of tensile strength, yield strength, and elongation, and calculate the mechanical property evaluation value of the finished aluminum foil of the current batch based on the data of tensile strength, yield strength, and elongation.

[0129] The working principle and beneficial effects of the above technical solution are as follows: The present invention uses an image acquisition device and a trained evaluation model to evaluate the surface smoothness. By conducting sampling antibacterial property, barrier property, and mechanical property quality inspection tests on each batch of finished aluminum foil, evaluate the sampling antibacterial property, barrier property, and mechanical property of each batch of finished aluminum foil. Evaluate the dimensional compliance of the finished aluminum foil of the current batch through sampling thickness detection. Finally, based on the surface smoothness evaluation value, antibacterial property evaluation value, barrier property evaluation value, mechanical property evaluation value, and dimensional compliance evaluation value of each batch of finished aluminum foil, obtain the comprehensive performance evaluation value of each batch of finished aluminum foil. When the comprehensive performance evaluation value of each batch of finished aluminum foil is greater than the preset comprehensive performance evaluation value, it proves that the current product is qualified; otherwise, it is unqualified.

[0130] Among them, the α evaluation values corresponding to the β-th sample in the finished aluminum foil of the current batch include the surface smoothness evaluation value, the antibacterial property evaluation value, the barrier property evaluation value, the mechanical property evaluation value, and the dimensional qualification evaluation value.

[0131] Example 8

[0132] On the basis of any one of Examples 1-7, an application of an aluminum foil packaging material is provided. The aluminum foil packaging material is prepared by using the preparation method of the aluminum foil packaging material in any one of Examples 1-7 and is used for packaging freeze-dried products. The freeze-dried products are not prone to moisture return inside the aluminum foil material, and the freeze-dried products are freeze-dried matsutake.

[0133] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A preparation method of an aluminum foil packaging material, characterized in that: It includes the following steps: S1. Prepare the core layer ingot, barrier layer ingot and functional layer ingot, and perform hot rolling on the core layer ingot, barrier layer ingot and functional layer ingot respectively to form a core layer casting plate, a barrier layer casting plate and a functional layer casting plate; S2. Stack the core layer casting plate, the barrier layer casting plate and the functional layer casting plate in sequence, fix them with a fixture and then put them into an annealing furnace, so that the core layer casting plate, the barrier layer casting plate and the functional layer casting plate are combined into one body to form a composite aluminum foil plate. Perform hot rolling on the composite aluminum foil plate. After the hot rolling is completed, conduct a preliminary test to determine the optimal thickness of the aluminum foil. Based on the test results, determine the preliminary optimal thickness of the aluminum foil, and perform cold rolling treatment based on the preliminary optimal thickness of the aluminum foil to finally form a preliminary aluminum foil; The preliminary aluminum foil includes a core layer, a barrier layer and a functional layer. The core layer is used to provide basic strength, the barrier layer is used to provide the barrier performance of the aluminum foil, including water vapor barrier performance and oxygen barrier performance, and the functional layer is used to provide antibacterial, light barrier and water vapor barrier functions; S4. Use a plasma treatment device to perform surface modification on the preliminary aluminum foil, and spray an antibacterial coating on the surface of the surface-modified preliminary aluminum foil; S5. Perform annealing treatment on the preliminary aluminum foil sprayed with the antibacterial coating to form a finished aluminum foil. Conduct sampling quality inspection on each batch of finished aluminum foils. After passing the quality inspection, perform slitting and packaging on them.

2. The preparation method of an aluminum foil packaging material according to claim 1, wherein: Step S1 includes the following steps: S11. Add the aluminum foil core layer raw material, barrier layer raw material and functional layer raw material into a melting furnace for melting according to the component ratio. The melting temperatures of the aluminum foil core layer raw material, barrier layer raw material and functional layer raw material are 700 - 800 °C, 700 - 750 °C and 750 - 800 °C respectively; S12. Pour the molten core layer raw material, barrier layer raw material and functional layer raw material into a die casting machine for cooling to form a core layer ingot, a barrier layer ingot and a functional layer ingot; S13. Put the core layer ingot, barrier layer ingot and functional layer ingot into a sawing machine for cutting, and perform milling on the cutting surface to ensure the surface is flat; S14. Put the cut core layer ingot, barrier layer ingot and functional layer ingot into an annealing furnace for homogenization treatment; S15. Perform hot rolling on the homogenized core layer ingot, barrier layer ingot and functional layer ingot to form a core layer casting plate, a barrier layer casting plate and a functional layer casting plate. The hot rolling temperature is 400 - 450 °C; The thicknesses of the core layer casting plate, the barrier layer casting plate and the functional layer casting plate are 10 - 20 mm, 8 - 15 mm and 10 - 18 mm respectively; The thickness of the hot rolling of the composite aluminum foil plate is 8 - 10 mm.

3. According to the method for preparing an aluminum foil packaging material described in claim 2, wherein: Component ratio of the core layer raw material: aluminum 99.3%, iron 0.1%, copper 0.1%, magnesium 0.15%, zirconium 0.05%, silicon 0.1%, titanium 0.1%, graphene oxide 0.05%, carbon nanotubes 0.05%; Component ratio of the barrier layer raw material: aluminum 99%, iron 0.05%, copper 0.05%, magnesium 0.05%, silicon 0.05%, titanium 0.05%, chromium 0.2%, yttrium 0.1%, tin 0.1%, nano-silica 0.3%, graphene 0.05%; Functional layer raw material composition ratio: aluminum 99.1%, iron 0.05%, copper 0.03%, magnesium 0.02%, silicon 0.05%, titanium 0.05%, polyvinylidene chloride 0.3%, ethylene-vinyl alcohol copolymer 0.2%, silver-zinc composite nanoparticles 0.1%, titanium dioxide nanotubes 0.1%.

4. The preparation method of an aluminum foil packaging material according to claim 1, characterized in that: After hot rolling, conduct a preliminary test to determine the optimal thickness of the aluminum foil. Based on the test results, determine the optimal thickness of the preliminary aluminum foil, including: S21. Cold roll the hot-rolled composite aluminum foil sheet at different cold rolling reduction rates to prepare several cold-rolled samples. Measure the thickness of each cold-rolled sample and record the thickness value. S22. Prepare each cold-rolled sample into a standard specimen according to the standard requirements of the tensile test. Use a universal material testing machine to conduct a tensile test on each cold-rolled sample and record the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test. S23. Generate a corresponding performance matrix based on the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test. Based on the performance matrix of each cold-rolled sample and the preset performance matrix, determine three alternative thicknesses. Customize three cold-rolled samples based on the alternative thicknesses and conduct a barrier property test on the cold-rolled samples. Based on the barrier property test results, determine the optimal thickness of the preliminary aluminum foil.

5. The preparation method of an aluminum foil packaging material according to claim 4, characterized in that: Step S23 includes: S231. Generate a tensile strength curve, a yield strength curve, and an elongation curve based on the tensile strength, yield strength, and elongation data of the cold-rolled sample during the test. S232. Extract the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve. Generate a tensile strength feature vector, a yield strength feature vector, and an elongation feature vector based on the key characteristic values of the tensile strength curve, the yield strength curve, and the elongation curve. Generate a performance matrix for the corresponding cold-rolled sample based on the tensile strength feature vector, the yield strength feature vector, and the elongation feature vector. S233. Calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix. Take the thicknesses corresponding to the three cold-rolled samples with the top three proximity values between the performance matrix of the cold-rolled sample and the preset performance matrix as the alternative thicknesses. Customize three cold-rolled samples based on the alternative thicknesses and conduct a barrier property test on the cold-rolled samples. Select the alternative thickness corresponding to the cold-rolled sample with the best barrier property as the optimal thickness of the preliminary aluminum foil.

6. The preparation method of an aluminum foil packaging material according to claim 5, wherein: Calculate the proximity between the performance matrix of the cold-rolled sample and the preset performance matrix: Among them, is the proximity between the performance matrix corresponding to the k-th cold-rolled sample and the preset performance matrix, x kij is the value in the i-th row and j-th column of the performance matrix corresponding to the k-th cold-rolled sample, x 0ij is the value in the i-th row and j-th column of the preset performance matrix, a is the total number of rows of the performance matrix, and b is the total number of columns of the performance matrix.

7. A method for preparing an aluminum foil packaging material according to claim 1, characterized in that: Step S3 includes: S31. Place the preliminary aluminum foil in a plasma treatment device. Set the gas type to argon or nitrogen and the treatment time to 30 seconds to 1 minute to improve the surface activity. S32. Use a spraying device to evenly spray the antibacterial coating on the surface of the preliminary aluminum foil. Control the coating thickness within 0.001 - 0.002 mm, where the antibacterial coating uses silver nanoparticles.

8. A method for preparing an aluminum foil packaging material according to claim 1, characterized in that: During the preparation process of each batch of aluminum foil packaging materials, at the end of each hot rolling or cold rolling step, sampling thickness detection is required to accept the current hot rolling or cold rolling results. The steps are as follows: Step 1: Extract m products after hot rolling or cold rolling from the currently finished products for thickness detection. The thickness detection steps are as follows: evenly divide each product after hot rolling or cold rolling into j detection segments along the length direction, take the midpoint of each detection segment for thickness detection, and obtain the thickness value at the midpoint of each detection segment; Step 2: Based on the thickness values at the midpoints of each detection segment of the m products after hot rolling or cold rolling, calculate the thickness qualification evaluation value of the currently finished product after hot rolling or cold rolling: Among them, W is the evaluation value of the thickness qualification of the product after current hot rolling or cold rolling, m is the total number of thickness detection samples in the product after current hot rolling or cold rolling, ξ1 is the influence coefficient of thickness accuracy on thickness qualification, n is the number of detection segments of the product after hot rolling or cold rolling, and H ij is the thickness value at the midpoint of the j-th detection segment in the i-th sampled product after hot rolling or cold rolling, H0 is the preset thickness value of the product after current hot rolling or cold rolling, and ξ2 is the influence coefficient of thickness uniformity on thickness qualification; If the thickness qualification evaluation value of the currently finished product after hot rolling or cold rolling is greater than the reference thickness qualification evaluation value, it proves that the current preparation step passes the acceptance. Otherwise, it proves that the current preparation step fails the acceptance, and an alarm prompt is given to promptly check and adjust the preparation equipment or preparation method.

9. A method for preparing an aluminum foil packaging material according to claim 1, characterized in that: Step S4 for quality inspection of the finished aluminum foil includes appearance evaluation, performance evaluation, and dimensional qualification evaluation; Among them, the appearance evaluation includes using an image acquisition device and a trained aluminum foil surface smoothness evaluation model to conduct sampling surface smoothness evaluation on each batch of finished aluminum foil to obtain the surface smoothness evaluation value of each batch of finished aluminum foil; The performance evaluation includes conducting sampling antibacterial performance, barrier performance, and mechanical performance quality inspection tests on each batch of finished aluminum foil to obtain the antibacterial performance evaluation value, barrier performance evaluation value, and mechanical performance evaluation value of each batch of finished aluminum foil; The dimensional qualification evaluation includes conducting sampling thickness detection on each batch of finished aluminum foil and calculating the dimensional qualification evaluation value of the currently batch of finished aluminum foil based on the thickness detection results; Based on the surface smoothness evaluation value, antibacterial performance evaluation value, barrier performance evaluation value, mechanical performance evaluation value, and dimensional qualification evaluation value of each batch of finished aluminum foil, obtain the comprehensive performance evaluation value of each batch of finished aluminum foil, and generate the quality inspection result based on the comprehensive performance evaluation value of each batch of finished aluminum foil; Among them, the comprehensive performance evaluation value of each batch of finished aluminum foil: where ∈ is the comprehensive performance evaluation value of the finished aluminum foil in the current batch, Z αβ is the α-th evaluation value corresponding to the β-th sample in the finished aluminum foil of the current batch, γ α is the weight of the α-th evaluation value, and y is the total number of samples of the finished aluminum foil in the current batch.

10. Application of an aluminum foil packaging material, which is prepared by using the preparation method of an aluminum foil material for freeze-dried product packaging described in any one of claims 1-9, characterized in that: The prepared aluminum foil packaging material is used for packaging freeze-dried products.

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