A high-adhesion, high-barrier aluminum-coated film and its preparation method

Abstract

This application relates to a high-adhesion, high-barrier aluminized film and its preparation method, belonging to the field of aluminized film technology. The film comprises polypropylene, monomeric silane acrylate, an initiator, a hydrolysis accelerator, a compatibilizer, an antioxidant, and a lubricant. By constructing a synergistic system composed of monomeric silane acrylate, an initiator, and a hydrolysis accelerator, and supplementing the aluminization process with a controllable micro-reaction environment, the performance is enhanced. The functional components remain chemically inert during processing and storage. Upon entering the aluminization stage, the photothermal energy released by the condensation of aluminum vapor is captured by the initiator, simultaneously triggering free radical polymerization and accelerator decomposition. The catalyst released by the latter, with the assistance of trace amounts of water vapor, efficiently drives the hydrolysis of silane groups and forms strong Si-O-Al covalent bonds with the fresh aluminum layer. This process synchronizes the cross-linking and densification of the substrate surface with the chemical bonding of the aluminum layer in time and space, achieving a combination of high adhesion, high barrier properties, and improved toughness.

Description

Technical Field

[0001] This application relates to the field of aluminized film technology, specifically to a high-adhesion, high-barrier aluminized film and its preparation method. Background Technology

[0002] Metallized polypropylene (PP) film is widely used in flexible packaging for food, pharmaceuticals, and electronics products due to its excellent moisture-blocking, light-shielding, and decorative effects, as well as its relatively low cost. Its traditional preparation method involves physical vapor deposition (PVD) to condense and deposit gaseous aluminum onto the surface of a plastic film under high vacuum. However, as a typical non-polar, low-surface-energy polymer, polypropylene's surface chemical inertness means that the deposited aluminum layer adheres primarily through physical van der Waals forces, resulting in low bonding strength. This leads to problems such as aluminum layer peeling and cracking during subsequent processing or use. Furthermore, the inherent molecular chain segment gaps and surface micro-defects in the plastic substrate itself limit the improvement in the performance of simply metallized films in blocking small molecules such as oxygen and water vapor, making it difficult to meet the stringent requirements of high-end packaging for long-lasting preservation and strong protection.

[0003] Currently, there are two main solutions to address these issues: one is to physically or chemically modify the substrate surface, such as through corona treatment, flame treatment, or plasma treatment, to increase surface energy and roughness to enhance the mechanical anchoring effect; the other is to pre-coat a specialized primer or adhesive layer before aluminizing, which acts as an intermediate medium to simultaneously bond the substrate and the aluminum layer. Additionally, some methods use barrier resins (such as EVOH and PA) as an intermediate layer, or add sheet-like nanofillers (such as montmorillonite) to the polypropylene matrix to extend the gas permeation path, thereby improving barrier properties independently. However, these methods typically suffer from complex processes or reduced film flexibility.

[0004] Therefore, it is of great significance to develop an aluminized film that combines high adhesion, high barrier properties, and good toughness. Summary of the Invention

[0005] This application provides a high-adhesion, high-barrier aluminum-coated film and its preparation method, which has the effects of high adhesion, high barrier properties, and good toughness.

[0006] This application provides a high-adhesion, high-barrier aluminum-coated film and its preparation method, which adopts the following technical solution: A high-adhesion, high-barrier aluminized film and its preparation method are disclosed. The film is prepared by co-extrusion and vacuum aluminization of a functional masterbatch comprising the following components in parts by weight: 65-80 parts of high melt index random copolymer polypropylene, 15-25 parts of monomeric silane acrylate, 1.5-3 parts of initiator, 0.5-2 parts of hydrolysis accelerator, 3-5 parts of compatibilizer, 0.5-1 part of antioxidant, and 0.5-1 part of lubricant. The method for preparing the aluminum-coated film includes the following steps: S1. Preparation of functional masterbatch: After premixing the raw materials in a high-speed mixer for 3-5 minutes, the raw materials are fed into a twin-screw extruder and processed at a processing temperature of 160℃ in zone 1, 170℃ in zone 2, 175℃ in zone 3, 175℃ in zone 4, and 170℃ at the die head, with a screw speed of 200-250 rpm and a vacuum degree of not less than -0.095 MPa, to obtain functional masterbatch. S2. Co-extrusion film forming: Using a three-layer co-extrusion casting equipment, 85-90 parts by weight of random copolymer polypropylene and 15-18 parts by weight of functional masterbatch are mixed as the functional layer raw material, homopolymer polypropylene is used as the core layer raw material, and copolymer polypropylene is used as the heat-sealing layer raw material for co-extrusion casting; the processing temperature of the functional layer is 175-185℃, the cooling roller temperature is 15-20℃, and a film with a thickness of 20-50μm is obtained. S3, Vacuum Aluminizing: Place the thin film obtained in step S2 into a vacuum aluminizing apparatus, and evacuate the chamber to a background vacuum of ≤5.0×10⁻⁶. -3 After Pa, an Ar / H2O mixed gas is introduced into the vapor deposition zone to maintain the working gas pressure at 1.0 × 10⁻⁶. -2 -5.0×10 -2 Pa; Start the aluminum wire evaporation source, control the aluminum evaporation temperature at 1350-1450℃, so that the surface temperature of the film during operation reaches 130-150℃, and maintain it for 0.8-1.5s, depositing an aluminum layer on the surface of the film functional layer to obtain a high-adhesion and high-barrier aluminum-coated film.

[0007] By adopting the above technical solution, the functional masterbatch uses high melt index random copolymer polypropylene as the matrix, ensuring good compatibility with functional components and the uniformity and integrity of the functional layer during subsequent co-extrusion film formation. The key active component in the masterbatch, monomeric silane acrylate, simultaneously carries acrylate double bonds and silane groups, providing a molecular basis for achieving free radical polymerization crosslinking and silane-aluminum bonding during the aluminizing stage. The introduction of a hydrolysis accelerator solves the bottleneck of slow reaction kinetics of silane groups under high vacuum conditions. It releases catalytic substances at the high temperature of aluminizing, ensuring efficient and rapid covalent bond (Si-O-Al) formation between silane and aluminum. In addition, the synergistic effect of compatibilizers, antioxidants, and lubricants ensures the chemical stability and dispersion uniformity of active components during masterbatch processing and film extrusion, preventing premature reaction or decomposition, and allowing the component activity to be retained in the aluminizing stage.

[0008] In the functional masterbatch preparation stage (step S1), the relatively mild zoned temperature setting and high-vacuum devolatilization ensure sufficient melt blending while minimizing the heat consumption of active functional groups and the moisture content in the system, thus preserving activity for subsequent reactions. Secondly, in the co-extrusion film forming stage (step S2), the functional masterbatch and base resin are mixed in a specific ratio and co-extruded as a surface layer. The film is rapidly cooled and shaped by controlling a low cooling roller temperature. This precisely fixes the functional components on the film surface and locks in their activity, constructing a pre-defined uniform interface layer for the subsequent aluminum plating reaction.

[0009] Ultimately, the performance is transformed in the core step of vacuum aluminum plating (step S3). By introducing an Ar / H2O mixed gas into the evaporation zone and maintaining the working pressure within a specific range, a controlled micro-moisture environment is created, providing the necessary and controllable reactants for the hydrolysis reaction of silanes. Simultaneously, controlling the aluminum evaporation temperature to reach 130-150°C on the film surface and maintaining it for 0.8-1.5 seconds matches the energy required for initiator decomposition and hydrolysis accelerator activation. Under this environment, the heat released during the aluminum plating process simultaneously triggers two key reactions: first, the initiator decomposition induces the polymerization and cross-linking of acrylate double bonds in monomeric silane acrylates, forming a dense network structure in situ on the substrate surface, improving the barrier properties of the film; second, the heat activates the hydrolysis accelerator, which, with the assistance of micro-moisture, catalyzes the hydrolysis of silane groups on the same molecule and forms strong Si-O-Al covalent bonds with the newly deposited active aluminum atoms, achieving a tight bond between the aluminum layer and the substrate, thereby obtaining high adhesion.

[0010] In summary, by using functional masterbatches to achieve the formation of a pre-defined interfacial structure of active components during the co-extrusion process, and then simultaneously triggering surface cross-linking densification and interfacial chemical bonding in the vacuum metallization stage using controlled energy and reaction environment, this process transforms traditional physical deposition into a one-step interfacial chemical synthesis. This results in improved barrier properties and strong aluminum layer adhesion in the metallized film, while maintaining the good processability and flexibility of the polypropylene substrate.

[0011] Optionally, the monomeric silane acrylate is methacryloxypropyltris(methylethyl ketone oxime)silane, with the general structural formula CH2=C(CH3)COO-(CH2)3-Si(ON=C(CH3)C2H5)3, and the preparation method of the methacryloxypropyltris(methylethyl ketone oxime)silane includes the following steps: S1. Under nitrogen protection and ice bath cooling, dissolve 3.05-3.10 mol of methyl ethyl ketone oxime and 3.05-3.10 mol of triethylamine in toluene, keep the temperature below 5℃, and add dropwise a toluene solution of 1 mol of methacryloxypropyltrichlorosilane. S2. After the addition is complete, the reaction system is slowly heated to 40-50℃ and the reaction continues for 6-8 hours. After the reaction is completed, the mixture is filtered, and the filtrate is washed with dilute hydrochloric acid, sodium bicarbonate solution and water in sequence until neutral. After drying with anhydrous sodium sulfate, the solvent and low-boiling substances are removed by vacuum distillation to obtain methacryloyloxypropyltris(methylethyl ketone oxime)silane.

[0012] By employing the above technical solution, the ketoxime group can effectively resist the attack of trace moisture in the material under the high temperature and high shear environment experienced during masterbatch granulation and film extrusion, suppressing the risk of pre-hydrolysis or self-condensation gelation before reaching the aluminizing reaction zone. This lays a key molecular foundation for ensuring that the active functional groups of silane are completely preserved at the aluminizing interface, thereby achieving high-density covalent bonding of the aluminum layer.

[0013] The preparation method involves a substitution reaction between methacryloxypropyltrichlorosilane and methyl ethyl ketoxime in the presence of triethylamine, representing an efficient and direct synthetic route. The dropwise addition under ice-bath cooling aims to gently initiate the reaction, manage the heat of reaction, and reduce impurity formation caused by localized overheating or side reactions of reactive intermediates. The subsequent reaction is continued at 40-50°C for 6-8 hours to ensure complete and thorough substitution of the chlorine atom by the ketoxime group. The subsequent systematic purification steps are for obtaining the target product in high purity.

[0014] Optionally, the hydrolysis promoter is a carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and the preparation method of the carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane includes the following steps: S1. Mix 1 mol of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with 3-5 mol of dimethyl carbonate and stir at 60-80℃ for 4-6 h. Then remove the generated methanol and excess dimethyl carbonate by vacuum distillation to obtain the carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0015] By employing the above technical solution, excess dimethyl carbonate is reacted with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane at 60-80℃ to protect the two primary amine groups at the molecule's ends via methoxyformylation, generating a carbamate structure with better thermal stability. The target product is then obtained through vacuum distillation purification. This process improves the thermal processing stability of the hydrolysis accelerator during melt blending granulation and film extrusion molding of polypropylene-based functional masterbatches. At processing temperatures not exceeding 200℃, the end-capped material maintains chemical inertness, effectively preventing strong alkaline amines from prematurely initiating side reactions such as hydrolysis and condensation of the silane component, thereby ensuring that the entire functional material system maintains a stable inert state and compositional uniformity before reaching the aluminizing process.

[0016] When the thin film enters the vacuum aluminizing chamber, its surface reaches a predetermined higher temperature range due to the latent heat of aluminum vapor condensation, causing the urethane-terminated material to undergo controlled thermal decomposition. This decomposition process simultaneously releases two substances: first, a highly catalytically active original diamine compound, whose released amine groups act as an alkaline catalyst, accelerating the hydrolysis rate of the main silane component at the interface; and second, a reactive methoxysilane component, which, after its own hydrolysis, can participate in the formation of the interfacial condensation network. Therefore, upon heating, this material transforms from a stable precursor to a hydrolysis catalyst and auxiliary reactive silane.

[0017] Optionally, the compatibilizer is polypropylene grafted with maleic anhydride.

[0018] By adopting the above technical solution, the polypropylene backbone of the compatibilizer has high thermodynamic compatibility with the polypropylene matrix, and can achieve deep entanglement of molecular chain segments; while the grafted maleic anhydride functional group can improve the dispersion uniformity and interfacial affinity of functional components in the matrix, effectively preventing phase separation caused by poor compatibility during processing and use.

[0019] Optionally, the initiator is composed of photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone and thermal initiator 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane in a weight ratio of 1:1-1.5.

[0020] By employing the above technical solution, the photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone primarily absorbs ultraviolet light from the strong radiation generated by the aluminum evaporation source, achieving photoinitiation at the interface and ensuring timely reaction initiation. Meanwhile, the decomposition temperature range of the thermal initiator 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane corresponds to the instantaneous high temperature reached on the substrate surface by aluminum vapor condensation, ensuring sufficient conversion and deepening of cross-linking of monomers in the heated region through thermal initiation. The synergistic effect of these two in this ratio provides a reliable driving force for synchronous cross-linking and bonding reactions at the interface, ensuring a dense and uniform final interfacial layer structure.

[0021] Optionally, the antioxidant is composed of antioxidant 168 and antioxidant 1010 in a mass ratio of 2:1-1.5.

[0022] By employing the above technical solution, antioxidant 1010 can efficiently capture and terminate free radicals generated during processing thermal degradation, while antioxidant 168 is responsible for decomposing the generated hydroperoxides and preventing them from initiating new chain oxidation reactions. The two work synergistically, each playing a role at different stages of the oxidation chain reaction, thereby enhancing the functional material system's resistance to thermo-oxidative aging during high-temperature processing.

[0023] Optionally, the lubricant is calcium stearate.

[0024] By adopting the above technical solution, calcium stearate, as a highly efficient internal lubricant, effectively reduces the friction between polymer molecular chains and between the melt and the metal surface of the processing equipment during the polypropylene melt processing. This improves the melt flowability and processing tolerance during the co-extrusion of functional masterbatch and surface layer, enabling the components to be formed into functional layers in a more uniform and stable state.

[0025] Optionally, in step S3, the volume partial pressure of water vapor in the Ar / H2O mixture is 1-5% of the total working pressure.

[0026] By adopting the above technical solution, a controlled micro-aqueous environment is created for the interfacial reaction, which solves the problem of the water molecule source necessary for the efficient hydrolysis of the terminal silane groups of monomeric silane acrylates after the hydrolysis promoter releases the catalyst, ensuring the generation of sufficient active silanol groups, and laying the foundation for the subsequent formation of Si-O-Al covalent bonds with aluminum.

[0027] In summary, this application includes at least one of the following beneficial technical effects: 1. By constructing a synergistic system composed of monomeric silane acrylate, initiator, and hydrolysis accelerator, and supplementing the aluminizing process with a controllable micro-reaction environment, a combination of high adhesion, high barrier properties, and improved toughness is achieved. The functional components remain chemically inert during processing and storage. Upon entering the aluminizing stage, the photothermal energy released by the condensation of aluminum vapor is captured by the initiator, simultaneously triggering free radical polymerization and accelerator decomposition. The catalyst released by the latter, with the assistance of trace amounts of water vapor, efficiently drives the hydrolysis of silane groups and forms strong Si-O-Al covalent bonds with the fresh aluminum layer. This process synchronizes the cross-linking and densification of the substrate surface with the chemical bonding of the aluminum layer in time and space, solving the problem of weak adhesion. The dense cross-linked network extends the gas permeation path and effectively prevents material embrittlement. Detailed Implementation

[0028] Preparation Example 1 The preparation method of methacryloyloxypropyltris(methylethyl ketone oxime)silane includes the following steps: S1. Under nitrogen protection and ice bath cooling, dissolve 3.05 mol of methyl ethyl ketone oxime and 3.05 mol of triethylamine in toluene, keep the temperature below 5°C, and add dropwise a toluene solution of 1 mol of methacryloxypropyltrichlorosilane. S2. After the addition is complete, the reaction system is slowly heated to 45°C and the reaction continues for 7 hours. After the reaction is completed, the mixture is filtered. The filtrate is washed with dilute hydrochloric acid, sodium bicarbonate solution and water in sequence until neutral. After drying with anhydrous sodium sulfate, the solvent and low-boiling substances are removed by vacuum distillation to obtain methacryloyloxypropyltris(methylethyl ketone oxime)silane.

[0029] Preparation Example 2 The carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is prepared by the following steps: S1. Mix 1 mol of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with 4 mol of dimethyl carbonate and stir at 70 °C for 5 h. Then remove the generated methanol and excess dimethyl carbonate by vacuum distillation to obtain the carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0030] Example 1 A high-adhesion, high-barrier aluminized film is prepared by co-extrusion and vacuum aluminization of a functional masterbatch comprising the following components in parts by weight: 80 parts of high melt index random copolymer polypropylene, 18 parts of monomeric silane acrylate, 2 parts of initiator, 1 part of hydrolysis accelerator, 4 parts of compatibilizer, 0.7 parts of antioxidant, and 0.8 parts of lubricant. Specifically, the monomeric silane acrylate was obtained using Preparation Example 1, and its general structural formula is CH2=C(CH3)COO-(CH2)3-Si(ON=C(CH3)C2H5)3; the hydrolysis accelerator was obtained using Preparation Example 2; the compatibilizer was polypropylene grafted with maleic anhydride; the initiator was composed of photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone and thermal initiator 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane in a weight ratio of 1:1.5; the antioxidant was composed of antioxidant 168 and antioxidant 1010 in a mass ratio of 2:1; and the lubricant was calcium stearate. A method for preparing a high-adhesion, high-barrier aluminum-coated film includes the following steps: S1. Preparation of functional masterbatch: After premixing the raw materials in a high-speed mixer for 5 minutes, the raw materials are fed into a twin-screw extruder and processed at the following temperatures: 160℃ in zone 1, 170℃ in zone 2, 175℃ in zone 3, 175℃ in zone 4, and 170℃ at the die head. The screw speed is 200 rpm and the vacuum degree is not lower than -0.095 MPa. The resulting material is melt-extruded, granulated, and dried to obtain the functional masterbatch. S2. Co-extrusion film forming: A three-layer co-extrusion casting equipment is used to mix 90 parts by weight of random copolymer polypropylene and 18 parts by weight of functional masterbatch as the functional layer raw material, homopolymer polypropylene as the core layer raw material, and copolymer polypropylene as the heat-sealing layer raw material for co-extrusion casting; wherein the processing temperature of the functional layer is 185℃, the cooling roller temperature is 20℃, and a film with a thickness of 30μm is obtained. S3, Vacuum Aluminizing: Place the thin film obtained in step S2 into a vacuum aluminizing apparatus, and evacuate the chamber to a background vacuum of ≤5.0×10⁻⁶. -3After Pa, an Ar / H2O mixed gas (with a water vapor volume partial pressure of 3% of the total working gas pressure) is introduced into the vapor deposition zone to maintain the working gas pressure at 1.0 × 10⁻⁶. -2 -5.0×10 -2 Pa; Start the aluminum wire evaporation source, control the aluminum evaporation temperature at 1400℃, so that the surface temperature of the film during operation reaches 140℃, and maintain it for 1.2s, depositing an aluminum layer on the surface of the film functional layer to obtain a high-adhesion and high-barrier aluminum-coated film.

[0031] Example 2 A high-adhesion, high-barrier aluminized film differs from Example 1 in that it is prepared by co-extrusion and vacuum aluminization of a functional masterbatch comprising the following components in parts by weight: 75 parts of high melt index random copolymer polypropylene, 20 parts of monomeric silane acrylate, 2 parts of initiator, 1 part of hydrolysis accelerator, 4 parts of compatibilizer, 0.7 parts of antioxidant, and 0.8 parts of lubricant.

[0032] Example 3 A high-adhesion, high-barrier aluminized film differs from Example 1 in that it is prepared by co-extrusion and vacuum aluminization of a functional masterbatch comprising the following components in parts by weight: 72 parts of high melt index random copolymer polypropylene, 25 parts of monomeric silane acrylate, 2 parts of initiator, 1 part of hydrolysis accelerator, 4 parts of compatibilizer, 0.7 parts of antioxidant, and 0.8 parts of lubricant.

[0033] Comparative Example 1 A high-adhesion, high-barrier aluminized film differs from Example 1 in that the functional layer in preparation step S1 uses 100% high melt index homopolymer PP, and standard corona treatment is performed before aluminization.

[0034] Comparative Example 2 A high-adhesion, high-barrier aluminum-coated film differs from Example 1 in that the monomeric silane acrylate is replaced in equal amounts with coupling agent KH-570, and the hydrolysis accelerator is replaced in equal amounts with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0035] Comparative Example 3 A high-adhesion, high-barrier aluminum-coated film differs from Example 1 in that the hydrolysis accelerator is replaced in equal amounts with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0036] Comparative Example 4 A high-adhesion, high-barrier aluminum-coated film differs from Example 1 in that monomeric silane acrylate is replaced with an equal amount of methyl methacrylate.

[0037] Comparative Example 5 A high-adhesion, high-barrier aluminized film differs from Example 1 in that the initiator is replaced with an equal amount of high melt index random copolymer polypropylene.

[0038] Comparative Example 6 A high-adhesion, high-barrier aluminum-coated film differs from Example 1 in that, during aluminum coating in step S3 of the preparation process, the volume partial pressure of water vapor in the Ar / H2O mixed gas is 0% of the total working gas pressure.

[0039] Comparative Example 7 A high-adhesion, high-barrier aluminum-coated film differs from Example 1 in that, during aluminum coating in step S3 of the preparation process, the volume partial pressure of water vapor in the Ar / H2O mixed gas is 9% of the total working gas pressure.

[0040] Detection example Adhesion: The peel strength was tested according to GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tapes"; Barrier properties: Water vapor transmission rate was tested according to GB / T 26253-2010 "Determination of water vapor transmission rate of plastic films and sheets by infrared detector method"; oxygen transmission rate was tested according to ASTM D3985 "Standard test method for oxygen transmission rate of plastic films and sheets using coulometric sensors". Toughness: Refer to GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets" to test the elongation at break; The specific test results are shown in Table 1.

[0041] Table 1

[0042] As shown in Table 1 of the performance test data for Examples 1-3 and Comparative Examples 1-2, the aluminized film on the PP substrate treated with conventional corona treatment in Comparative Example 1 has weak adhesion and poor barrier properties. Although silane and initiator were added in Comparative Example 2, the silane was easily pre-hydrolyzed during processing or failed to bond effectively. Although its adhesion and barrier properties were improved, they were not as good as those of the Examples, proving that simple physical blending cannot achieve the expected results.

[0043] As shown in Table 1 of the performance test data for Examples 1-3 and Comparative Examples 3-5, Comparative Example 3 lacks the alkaline catalytic environment provided by the hydrolysis promoter, resulting in insufficient covalent bonding reaction between silane and aluminum, thus limiting the improvement in adhesion. Comparative Example 4 also lacks an active silane capable of forming covalent bonds with aluminum, failing to achieve high adhesion and demonstrating the role of the prepared monomeric silane acrylate. Comparative Example 5 lacks an initiator; the absence of a photothermal initiation system prevents the effective initiation of the acrylate crosslinking reaction.

[0044] As can be seen from the performance test data in Table 1 of Examples 1-3 and Comparative Examples 6-7, controllable water vapor assistance is indispensable for starting and accelerating the hydrolysis step in a high vacuum environment.

[0045] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a high-adhesion, high-barrier aluminum-coated film, characterized in that, The product is prepared by co-extrusion and vacuum metallization of a functional masterbatch consisting of the following components in parts by weight: 65-80 parts of high melt index random copolymer polypropylene, 15-25 parts of monomeric silane acrylate, 1.5-3 parts of initiator, 0.5-2 parts of hydrolysis accelerator, 3-5 parts of compatibilizer, 0.5-1 part of antioxidant, and 0.5-1 part of lubricant. The method for preparing the aluminum-coated film includes the following steps: S1. Preparation of functional masterbatch: After premixing the raw materials in a high-speed mixer for 3-5 minutes, the raw materials are fed into a twin-screw extruder and processed at a processing temperature of 160℃ in zone 1, 170℃ in zone 2, 175℃ in zone 3, 175℃ in zone 4, and 170℃ at the die head, with a screw speed of 200-250 rpm and a vacuum degree of not less than -0.095 MPa, to obtain functional masterbatch. S2. Co-extrusion film forming: Using a three-layer co-extrusion casting equipment, 85-90 parts by weight of random copolymer polypropylene and 15-18 parts by weight of functional masterbatch are mixed as the functional layer raw material, homopolymer polypropylene is used as the core layer raw material, and copolymer polypropylene is used as the heat-sealing layer raw material for co-extrusion casting; the processing temperature of the functional layer is 175-185℃, the cooling roller temperature is 15-20℃, and a film with a thickness of 20-50μm is obtained. S3, Vacuum Aluminizing: Place the thin film obtained in step S2 into a vacuum aluminizing apparatus, and evacuate the chamber to a background vacuum of ≤5.0×10⁻⁶. -3 After Pa, an Ar / H2O mixed gas is introduced into the vapor deposition zone to maintain the working gas pressure at 1.0 × 10⁻⁶. -2 -5.0×10 -2 Pa; Start the aluminum wire evaporation source, control the aluminum evaporation temperature at 1350-1450℃, so that the surface temperature of the film during operation reaches 130-150℃, and maintain it for 0.8-1.5s, depositing an aluminum layer on the surface of the film functional layer to obtain a high-adhesion and high-barrier aluminum-coated film.

2. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The monomeric silane acrylate is methacryloxypropyltris(methylethyl ketone oxime)silane, with the general structural formula CH2=C(CH3)COO-(CH2)3-Si(ON=C(CH3)C2H5)3. The preparation method of the methacryloxypropyltris(methylethyl ketone oxime)silane includes the following steps: S1. Under nitrogen protection and ice bath cooling, dissolve 3.05-3.10 mol of methyl ethyl ketone oxime and 3.05-3.10 mol of triethylamine in toluene, keep the temperature below 5℃, and add dropwise a toluene solution of 1 mol of methacryloxypropyltrichlorosilane. S2. After the addition is complete, the reaction system is slowly heated to 40-50℃ and the reaction continues for 6-8 hours. After the reaction is completed, the mixture is filtered, and the filtrate is washed with dilute hydrochloric acid, sodium bicarbonate solution and water in sequence until neutral. After drying with anhydrous sodium sulfate, the solvent and low-boiling substances are removed by vacuum distillation to obtain methacryloyloxypropyltris(methylethyl ketone oxime)silane.

3. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The hydrolysis accelerator is a carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and the preparation method of the carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane includes the following steps: S1. Mix 1 mol of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with 3-5 mol of dimethyl carbonate and stir at 60-80℃ for 4-6 h. Then remove the generated methanol and excess dimethyl carbonate by vacuum distillation to obtain the carbamate-terminated product of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

4. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The compatibilizer is polypropylene grafted with maleic anhydride.

5. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The initiator is composed of photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone and thermal initiator 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane in a weight ratio of 1:1-1.

5.

6. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The antioxidant is composed of antioxidant 168 and antioxidant 1010 in a mass ratio of 2:1-1.

5.

7. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, The lubricant is calcium stearate.

8. The method for preparing a high-adhesion, high-barrier aluminized film according to claim 1, characterized in that, In step S3, the volume partial pressure of water vapor in the Ar / H2O mixture is 1-5% of the total working pressure.

9. A high-adhesion, high-barrier aluminized film, characterized in that, Obtained by the preparation method according to any one of claims 1-8.

Images