Cellulose aluminum laminated film

Abstract

The invention discloses a cellulose aluminum laminated film, and belongs to the technical field of composite films. The preparation method of the cellulose aluminum laminated film comprises the following steps: adding cellulose acetate, starch, a natural extract and benzalkonium chloride into a mixed solvent, stirring, and defoaming to obtain a film coating solution; coating a glass substrate with the coating liquid, carrying out heat treatment, and then taking down from the substrate to obtain a regenerated cellulose membrane; evaporating metal aluminum on the upper surface of the regenerated cellulose membrane to form an aluminum-plated layer; and coating the lower bottom surface of the regenerated cellulose film with a polyurethane adhesive, and curing to form a polyurethane coating, thereby obtaining the cellulose aluminum laminated film. The cellulose aluminum laminated film prepared by the invention has excellent barrier property, can be applied to products with high moisture-proof requirements, effectively blocks external oxygen and moisture, and is green and environment-friendly, and the preparation method is simple and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of composite films, and in particular relates to a cellulose aluminum-plated film. Background Art

[0002] Aluminized film is a composite film material that combines the advantages of both plastic film and metal aluminum foil. It not only has good aesthetics, light-shielding properties, and UV protection, but also can play a role in moisture barrier and is widely used in packaging fields such as food, medicine, and cosmetics. Aluminized film is generally made through a vacuum aluminum plating process, where high-purity metal aluminum is evaporated into gas at high temperature and then deposited on the surface of the plastic film, giving the film a metallic luster and improving its barrier properties.

[0003] For example, Chinese patent CN109836726A discloses a PVC aluminized film and its preparation method, wherein the PVC aluminized film is composed of a PVC substrate layer, an aluminized layer and two ink layers, and is first vacuum aluminized to form a dense aluminized layer on the PVC substrate, and then the ink layer is printed. The aluminized film prepared by the patent has lower oxygen permeability and water vapor permeability, and the adhesion of the aluminized layer is good. Chinese patent CN117429102A discloses a high barrier aluminized film preparation process, wherein the aluminized film is composed of a heat seal layer, an intermediate layer, and a corona layer, and is cast in three layers to co-extrude to obtain a base film, and then is sent to an evaporation boat for aluminization; wherein the heat seal layer material is ternary low-temperature heat seal polypropylene and a modifier, the intermediate layer material is propylene and ethylene, and the corona layer material is binary copolymer PP, cycloolefin copolymer and high-viscosity elastic body, and the aluminized film prepared by the patent has the characteristics of high barrier, and the interlayer composite fastness is stronger.

[0004] However, the raw materials used in traditional aluminized films are non-degradable plastics, which will form white pollution when discarded. It is difficult to recycle and treat, which is not in line with the development trend of green environmental protection. Therefore, the development of degradable alternatives has become the key. In this context, regenerated cellulose films prepared from green raw materials such as natural cellulose have gradually become a hot spot for research and application. Cellulose films have the advantages of high transparency, antistatic, degradability, and oxygen barrier. They can replace traditional plastics to make cellulose aluminized films for food packaging and cosmetic packaging. This method not only solves the problem that traditional aluminized films are difficult to degrade, but also provides the packaging industry with a new material that is both beautiful, practical and environmentally friendly. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a cellulose aluminum-plated film, which is composed of a regenerated cellulose film, an aluminum-plated layer and a polyurethane coating, wherein the regenerated cellulose film uses degradable cellulose acetate as a main raw material, and the barrier performance of the cellulose film is further improved by adding specific starch, which is functionalized pea starch; the cellulose aluminum-plated film of the present invention is green and environmentally friendly, and has a simple preparation method, and can be applied to products with high moisture-proof requirements to effectively block external oxygen and moisture.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for preparing a cellulose aluminum-plated film, comprising the following steps:

[0008] Cellulose acetate, starch, natural extracts and benzalkonium chloride are added to a mixed solvent, stirred and degassed to obtain a coating liquid; the starch is functionalized pea starch; the natural extract is oregano extract; the coating liquid is coated on a glass substrate, heat-treated, and then removed from the substrate to obtain a regenerated cellulose film; metallic aluminum is evaporated onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, cured to form a polyurethane coating, and the cellulose aluminum-plated film is obtained.

[0009] Preferably, a method for preparing a cellulose aluminum-plated film comprises the following steps:

[0010] 30-50 parts by weight of cellulose acetate, 5-15 parts by weight of starch, 3-5 parts by weight of natural extracts, and 0.5-1.5 parts by weight of benzalkonium chloride are added to 400-500 parts by weight of a mixed solvent, stirred at 35-45° C. and 60-100 rpm for 15-20 hours, and vacuum degassed to obtain a coating liquid; the starch is functionalized pea starch; the natural extract is oregano extract; the coating liquid is coated on a glass substrate, heat-treated, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, cured to form a polyurethane coating, and the cellulose aluminum-plated film is obtained.

[0011] Preferably, the mixed solvent consists of acetone and N,N-dimethylacetamide; the weight ratio of acetone to N,N-dimethylacetamide is 5:2-4.

[0012] Preferably, the heat treatment conditions are: heat treatment at 55-65°C for 40-60 min.

[0013] Preferably, the curing conditions are: curing at 75-85° C. for 1-3 hours.

[0014] Preferably, the thickness of the regenerated cellulose film is 19-22 μm.

[0015] Preferably, the thickness of the aluminum plating layer is 20-23 μm.

[0016] Preferably, the coating amount of the polyurethane adhesive is 2-4 g / m 2 .

[0017] Preferably, the functionalized pea starch is prepared by the following method:

[0018] The pea starch is mixed with water, the pH is adjusted to alkaline, lipase is added for enzymolysis, the pH is adjusted to neutral, pullulanase is added for enzymolysis, high temperature heating is performed, cooling is performed, centrifugation is performed, and the precipitate is freeze-dried to obtain pretreated pea starch;

[0019] The pretreated pea starch is mixed evenly with water, the pH is adjusted to alkaline, and then 2-nonenylsuccinic anhydride is added dropwise, heated to react, and then the pH is adjusted to acidic, and aluminum nitrate is added to continue the reaction, cooled, centrifuged, and the precipitate is washed and freeze-dried to obtain functionalized pea starch.

[0020] The regenerated cellulose film of the present invention further improves the barrier property and anti-aging property of the regenerated cellulose film by adding specific functionalized pea starch.

[0021] In the process of preparing functionalized pea starch of the present invention, firstly, the pea starch is subjected to dual enzymolysis treatment of lipase and pullulanase, thereby destroying the crystal structure inside the starch granules, making the starch granules more fine and uniform. This pretreatment not only improves the solubility and dispersibility of the starch, but also enhances its compatibility with cellulose acetate and other components; then, 2-nonenyl succinic anhydride is added dropwise under alkaline conditions for esterification reaction, further introducing hydrophobic long chains, reducing the water holding capacity of the starch granules, thereby reducing the free water content in the film, which not only helps to improve the water vapor barrier of the film, but also enhances the mechanical strength and stability of the film; finally, adding aluminum nitrate helps to form a cross-linked structure, further enhancing the interaction force between the starch granules, and this cross-linked structure can effectively prevent the penetration of small molecules such as water and oxygen, thereby improving the overall barrier performance of the film. At the same time, due to the refinement of the starch granules and the presence of the cross-linked structure, the aging and regeneration of the starch can be inhibited, and the anti-aging performance of the film is also improved, making its barrier performance more stable and its service life longer.

[0022] Preferably, the functionalized pea starch is prepared by the following method:

[0023] 20-40 parts by weight of pea starch and 150-200 parts by weight of water are mixed evenly, the pH is adjusted to 8.5-9.5, and then 1-3 parts by weight of lipase are added, and enzymolysis is performed at 35-45° C. for 40-50 minutes, then the pH is adjusted to neutral, and 2-4 parts by weight of pullulanase are added, and enzymolysis is performed at 55-65° C. for 8-15 hours, and then heated at 120-130° C. and 90-150 kPa for 10-30 minutes, cooled to room temperature, centrifuged, and the precipitate is freeze-dried to obtain pretreated pea starch;

[0024] 10-30 parts by weight of pretreated pea starch and 70-100 parts by weight of water are mixed evenly, the pH is adjusted to 8.0-9.0, and then 2-5 parts by weight of 2-nonenylsuccinic anhydride are added dropwise, and the dropping time is controlled to be 40-60 minutes. After the dropping is completed, the mixture is reacted at 30-40° C. for 3-5 hours, and then the pH is adjusted to 4.0-5.0, and 1-3 parts by weight of aluminum nitrate are added to continue the reaction for 0.5-1.5 hours, and the mixture is cooled to room temperature and centrifuged. The precipitate is washed with water and ethanol for 1-3 times in sequence, and freeze-dried to obtain functionalized pea starch.

[0025] Preferably, the oregano extract is prepared by the following method:

[0026] The whole oregano herb is crushed and sieved to obtain oregano powder; the oregano powder is added to an extraction solvent, ultrasonically treated, then heated for extraction, filtered, the filtrate is collected, the residue is repeatedly extracted, and the filtrate is combined after the extraction is completed, and concentrated under reduced pressure to obtain an oregano extract.

[0027] The present invention applies the antibacterial and antifungal effects of oregano extract to the regenerated cellulose film, and uses it in combination with benzalkonium chloride. The two work together to further improve the antibacterial and antifungal properties of the regenerated cellulose film compared to a single component.

[0028] Oregano extract is rich in various phenolic compounds and terpenoid compounds, and these ingredients have broad-spectrum antibacterial activity, and benzalkonium chloride belongs to quaternary ammonium surfactants, which can change the permeability of bacterial cell membrane, make the intracellular material of bacterial cell extravasation, hinder its metabolism and play a bactericidal effect, and when the two are used in combination, the synergistic inhibition of different harmful bacteria can be achieved, and stronger antibacterial and mildew-proof effects are exerted. In addition, oregano extract also has antioxidant properties, which helps to extend the shelf life of food. Further, the present invention adopts the extraction solvent composed of isopropyl alcohol and n-propyl acetate to prepare oregano extract, and the synergistic effect of the two solvents helps to break the plant cell wall structure, promotes the target compound to be released from the cell matrix, and improves the extraction rate. Moreover, the two mixed use can reduce surface tension to a certain extent, promote solvent penetration into the inside of plant tissue, accelerate mass transfer process, and be easier to extract active ingredients. It can be seen that in the preparation of oregano extract, the above-mentioned extraction solvent can improve the content of active ingredients in extraction efficiency and extract, realize the effective combination of natural plant extract and chemical antibacterial agent, and significantly improve the functional characteristics of regenerated cellulose film.

[0029] Preferably, the oregano extract is prepared by the following method:

[0030] The whole herb of oregano (Origanum vulgare L.) that has been washed and dried is crushed and passed through a 80-150 mesh sieve to obtain oregano powder; 10-20 parts by weight of the oregano powder is added to 70-100 parts by weight of an extraction solvent, ultrasonicated at 100-200W and 30-50kHz for 40-60min, then extracted at 85-95°C for 60-80min, filtered, the filtrate is collected, and the extraction of the residue is repeated 1-3 times. After the extraction, the filtrates are combined, concentrated under reduced pressure to remove the solvent, and the oregano extract is obtained.

[0031] Preferably, the extraction solvent consists of isopropanol and n-propyl acetate; the weight ratio of isopropanol to n-propyl acetate is 3-5:1.

[0032] The present invention also provides a cellulose aluminum-plated film prepared by the above method.

[0033] Beneficial effects of the present invention:

[0034] The invention provides a cellulose aluminum-plated film, which is composed of a regenerated cellulose film, an aluminum-plated layer and a polyurethane coating. The film is green and environmentally friendly, has a simple preparation method, can be applied to products with high moisture-proof requirements, and effectively blocks external oxygen and moisture. The regenerated cellulose film uses degradable cellulose acetate as a main raw material, and by adding a specific starch, the starch is functionalized pea starch, which further improves the barrier performance of the cellulose film, and by adding a natural extract (oregano extract) and benzalkonium chloride, the cellulose film is endowed with good antibacterial and anti-mildew properties. DETAILED DESCRIPTION

[0035] The above-mentioned invention contents of the present invention are further described in detail below in conjunction with specific implementation methods. The embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the contents of the present invention and implement them accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be included in the protection scope of the present invention.

[0036] Cellulose acetate, acetyl group: 39.8 wt %, was purchased from Shanghai Yien Chemical Technology Co., Ltd.

[0037] Polyurethane adhesive, model: RJ8315 / 8315B, was purchased from Sichuan Tubao New Material Technology Co., Ltd.

[0038] Pea starch, fineness: 100 mesh, whiteness: 90%, ash content: 0.5%, was purchased from Shandong Furun Biotechnology Co., Ltd.

[0039] Example 1

[0040] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0041] 30 parts by weight of cellulose acetate, 5 parts by weight of functionalized pea starch, 3 parts by weight of oregano extract, and 0.5 parts by weight of benzalkonium chloride are added to 400 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:2, stirred at 35°C and 60rpm for 20 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 55°C for 60 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 75°C for 3 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2g / m 2 .

[0042] The functionalized pea starch is prepared by the following method:

[0043] 30 parts by weight of pea starch and 170 parts by weight of water are mixed uniformly, the pH is adjusted to 9.0, and then 1.5 parts by weight of lipase is added, and enzymolysis is performed at 40° C. for 45 minutes. Then, the pH is adjusted to neutral, and 2.5 parts by weight of pullulanase is added, and enzymolysis is performed at 60° C. for 10 hours. Then, the mixture is heated at 126° C. and 139 kPa for 15 minutes, cooled to room temperature, centrifuged, and the precipitate is freeze-dried to obtain pretreated pea starch; wherein the enzyme activity of the lipase is 30000 u / g, and the enzyme activity of the pullulanase is 2000 u / g;

[0044] Take 20 parts by weight of pretreated pea starch and 80 parts by weight of water and mix them evenly, adjust the pH to 8.5, then add 3.5 parts by weight of 2-nonenylsuccinic anhydride, control the dropping time to 50 minutes, react at 35°C for 4 hours after the addition is completed, then adjust the pH to 4.5, add 2 parts by weight of aluminum nitrate and continue to react for 1 hour, cool to room temperature, centrifuge, wash the precipitate twice with water and ethanol in turn, and freeze-dry to obtain functionalized pea starch.

[0045] The oregano extract is prepared by the following method:

[0046] The cleaned and dried whole oregano herb was crushed and passed through a 100-mesh sieve to obtain oregano powder; 15 parts by weight of oregano powder was added to 85 parts by weight of an extraction solvent, wherein the extraction solvent consisted of isopropanol and n-propyl acetate in a weight ratio of 4:1, and ultrasonicated at 150W and 40kHz for 50 minutes, then extracted at 90°C for 70 minutes, filtered, and the filtrate was collected. The residue was extracted twice, and the filtrates were combined after extraction, and the solvent was removed by vacuum concentration to obtain an oregano extract.

[0047] Example 2

[0048] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0049] 50 parts by weight of cellulose acetate, 15 parts by weight of functionalized pea starch, 5 parts by weight of oregano extract, and 1.5 parts by weight of benzalkonium chloride are added to 500 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:4, stirred at 45°C and 100rpm for 15 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 65°C for 40 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 85°C for 1 hour to form a polyurethane coating to obtain the cellulose aluminum-plated film. Among them, the thickness of the regenerated cellulose film is 22μm; the thickness of the aluminum-plated layer is 23μm; the coating amount of the polyurethane adhesive is 4g / m 2 .

[0050] The functionalized pea starch is the same as that in Example 1; and the oregano extract is the same as that in Example 1.

[0051] Example 3

[0052] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0053] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 20μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0054] The functionalized pea starch is the same as that in Example 1; and the oregano extract is the same as that in Example 1.

[0055] Example 4

[0056] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0057] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0058] The functionalized pea starch is prepared by the following method:

[0059] Take 20 parts by weight of pea starch and 80 parts by weight of water and mix them evenly, adjust the pH to 8.5, then add 3.5 parts by weight of 2-nonenylsuccinic anhydride, control the dropping time to 50 minutes, react at 35°C for 4 hours after the addition is completed, then adjust the pH to 4.5, add 2 parts by weight of aluminum nitrate and continue to react for 1 hour, cool to room temperature, centrifuge, wash the precipitate twice with water and ethanol in turn, and freeze-dry to obtain functionalized pea starch.

[0060] The oregano extract is the same as that in Example 1.

[0061] Example 5

[0062] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0063] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0064] The functionalized pea starch is prepared by the following method:

[0065] 30 parts by weight of pea starch and 170 parts by weight of water were mixed evenly, the pH was adjusted to 9.0, and then 1.5 parts by weight of lipase was added, and enzymolysis was performed at 40°C for 45 minutes, and then the pH was adjusted to neutral, and 2.5 parts by weight of pullulanase was added, and enzymolysis was performed at 60°C for 10 hours, and then heated at 126°C and 139 kPa for 15 minutes, cooled to room temperature, centrifuged, and the precipitate was freeze-dried to obtain functionalized pea starch. The enzyme activity of lipase is 30000u / g, and the enzyme activity of pullulanase is 2000u / g.

[0066] The oregano extract is the same as that in Example 1.

[0067] Example 6

[0068] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0069] 40 parts by weight of cellulose acetate, 10 parts by weight of pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Among them, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0070] The oregano extract is the same as that in Example 1.

[0071] Example 7

[0072] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0073] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0074] The functionalized pea starch is the same as that in Example 1.

[0075] The oregano extract is prepared by the following method:

[0076] The cleaned and dried whole oregano herb was crushed and passed through a 100-mesh sieve to obtain oregano powder; 15 parts by weight of oregano powder was added to 85 parts by weight of an extraction solvent, wherein the extraction solvent was isopropanol, and ultrasonicated at 150W and 40kHz for 50 minutes, and then extracted at 90°C for 70 minutes, filtered, and the filtrate was collected. The residue was extracted twice, and the filtrates were combined after the extraction, and the solvent was removed by vacuum concentration to obtain an oregano extract.

[0077] Example 8

[0078] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0079] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, 4 parts by weight of oregano extract, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Wherein, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0080] The functionalized pea starch is the same as that in Example 1.

[0081] The oregano extract is prepared by the following method:

[0082] The cleaned and dried whole oregano herb was crushed and passed through a 100-mesh sieve to obtain oregano powder; 15 parts by weight of oregano powder was added to 85 parts by weight of an extraction solvent, wherein the extraction solvent was n-propyl acetate, and ultrasonicated at 150 W and 40 kHz for 50 min, and then extracted at 90° C. for 70 min, filtered, and the filtrate was collected. The residue was extracted twice, and the filtrates were combined after the extraction, and the solvent was removed by vacuum concentration to obtain an oregano extract.

[0083] Example 9

[0084] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0085] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, and 1 part by weight of benzalkonium chloride are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Among them, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0086] The functionalized pea starch is the same as that in Example 1.

[0087] Example 10

[0088] A method for preparing a cellulose aluminum-plated film comprises the following steps:

[0089] 40 parts by weight of cellulose acetate, 10 parts by weight of functionalized pea starch, and 4 parts by weight of oregano extract are added to 450 parts by weight of a mixed solvent, wherein the mixed solvent is composed of acetone and N,N-dimethylacetamide in a weight ratio of 5:3, stirred at 40°C and 80rpm for 18 hours, and vacuum degassed to obtain a coating liquid; the coating liquid is coated on a glass substrate, heat treated at 60°C for 50 minutes, and then removed from the substrate to obtain a regenerated cellulose film; a vacuum aluminum plating device is used to evaporate metallic aluminum (with a purity of 99.9%) onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, and cured at 80°C for 2 hours to form a polyurethane coating to obtain the cellulose aluminum-plated film. Among them, the thickness of the regenerated cellulose film is 19μm; the thickness of the aluminum-plated layer is 20μm; the coating amount of the polyurethane adhesive is 2.5g / m 2 .

[0090] The functionalized pea starch is the same as that in Example 1.

[0091] The oregano extract is the same as that in Example 1.

[0092] Test Example 1

[0093] The barrier properties and anti-aging properties of the aluminum-coated cellulose film obtained in the above example were measured. The oxygen permeability and water vapor permeability were tested according to the standard GB / T40266-2021, and the anti-aging properties were tested after aging for 168 hours at 65°C and 95% humidity. The results are shown in Table 1.

[0094] Table 1 Test results of barrier and anti-aging properties of cellulose aluminum-coated films

[0095]

[0096]

[0097] Test Example 2

[0098] The antibacterial and anti-mildew properties of the regenerated cellulose film obtained in the above examples were measured. The antibacterial properties were tested according to the reference standard GB / T37206-2018 (Escherichia coli CGMCC1.2463, Staphylococcus aureus CGMCC1.2910), and the anti-mildew properties were tested according to the reference standard GB / T24128-2018. The results are shown in Table 2.

[0099] Table 2 Test results of antibacterial and antifungal properties of regenerated cellulose film

[0100]

[0101] From the comparison of the above test results, it can be seen that the aluminum-plated cellulose films obtained in Examples 1-3 have excellent barrier properties, anti-aging properties, and antibacterial and mildew-proof properties. This is because the regenerated cellulose film of the present invention effectively improves the barrier properties and anti-aging properties of the regenerated cellulose film by adding specific functionalized pea starch, and at the same time, the addition of specific oregano extract and benzalkonium chloride gives the cellulose film good antibacterial and mildew-proof properties. Compared with Examples 1-3, no specific functionalized pea starch was added in Examples 4-6. It can be seen from Table 1 that its barrier properties and anti-aging properties have deteriorated; compared with Examples 1-3, no specific oregano extract and benzalkonium chloride were used simultaneously in Examples 7-10. It can be seen from Table 2 that the antibacterial and mildew-proof properties have deteriorated. This shows that Examples 4-10 did not adopt the necessary technical solutions of the present invention, resulting in a certain degree of decline in the corresponding performance tests, which further proves the importance of the necessary technical solutions defined by the present invention to its technical effects.

[0102] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a cellulose aluminum-plated film, characterized in that: The following steps are involved: Cellulose acetate, starch, natural extracts and benzalkonium chloride are added to a mixed solvent, stirred and degassed to obtain a coating liquid; the starch is functionalized pea starch; the natural extract is oregano extract; the coating liquid is coated on a glass substrate, heat-treated, and then removed from the substrate to obtain a regenerated cellulose film; metallic aluminum is evaporated onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, cured to form a polyurethane coating, and the cellulose aluminum-plated film is obtained.

2. The method for preparing aluminized cellulose film according to claim 1, characterized in that: The following steps are involved: 30-50 parts by weight of cellulose acetate, 5-15 parts by weight of starch, 3-5 parts by weight of natural extracts, and 0.5-1.5 parts by weight of benzalkonium chloride are added to 400-500 parts by weight of a mixed solvent, stirred, and degassed to obtain a coating liquid; the starch is functionalized pea starch; the natural extract is oregano extract; the coating liquid is coated on a glass substrate, heat-treated, and then removed from the substrate to obtain a regenerated cellulose film; metallic aluminum is evaporated onto the upper surface of the regenerated cellulose film to form an aluminum-plated layer; a polyurethane adhesive is coated on the lower bottom surface of the regenerated cellulose film, cured to form a polyurethane coating, and the cellulose aluminum-plated film is obtained.

3. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The functionalized pea starch is prepared by the following method: The pea starch is mixed with water, the pH is adjusted to alkaline, lipase is added for enzymolysis, the pH is adjusted to neutral, pullulanase is added for enzymolysis, high temperature heating is performed, cooling is performed, centrifugation is performed, and the precipitate is freeze-dried to obtain pretreated pea starch; The pretreated pea starch is mixed evenly with water, the pH is adjusted to alkaline, and then 2-nonenylsuccinic anhydride is added dropwise, heated to react, and then the pH is adjusted to acidic, and aluminum nitrate is added to continue the reaction, cooled, centrifuged, and the precipitate is washed and freeze-dried to obtain functionalized pea starch.

4. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The oregano extract is prepared by the following method: The whole oregano plant is crushed and sieved to obtain oregano powder; the oregano powder is added to an extraction solvent consisting of isopropyl alcohol and n-propyl acetate, subjected to ultrasonic treatment, and then subjected to heating extraction, filtered, and the filtrate is collected. The residue is repeatedly extracted, and the filtrate is combined after the extraction is completed, and concentrated under reduced pressure to obtain an oregano extract.

5. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The mixed solvent consists of acetone and N,N-dimethylacetamide.

6. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The heat treatment conditions are: heat treatment at 55-65°C for 40-60 minutes; the curing conditions are: curing at 75-85°C for 1-3 hours.

7. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The thickness of the regenerated cellulose film is 19-22 μm.

8. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The thickness of the aluminum plating layer is 20-23 μm.

9. The method for preparing aluminized cellulose film according to claim 1 or 2, characterized in that: The coating amount of the polyurethane adhesive is 2-4 g / m 2 .

10. A cellulose aluminum-plated film, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

Images