Water-based high-activity poly-carbon packaging material as well as preparation method and application thereof

Abstract

The invention discloses a high-barrier-performance water-based high-activity poly-carbon packaging material and a preparation method and application thereof, and belongs to the field of functional packaging materials, the packaging material is of a three-layer composite gradient structure, layers are tightly combined through an interface cross-linking agent, an inner layer takes aliphatic polycarbonate as a matrix, nano-zinc oxide and beta-cyclodextrin are added, and an outer layer takes aliphatic polycarbonate as a matrix; the antibacterial property and the compatibility are realized; the middle layer is composed of montmorillonite, graphene oxide, layered boron nitride, an organic silane coupling agent and Fe3O4 nanoparticles, and a continuous labyrinth type barrier network is formed through magnetic modification treatment; and the outer layer takes aliphatic polycarbonate as a matrix, is compounded with polytetrafluoroethylene micro powder and an anti-ultraviolet agent, and has wear resistance and ageing resistance. During preparation, the membrane material with high barrier, low solvent residue and excellent mechanical property is prepared by layer-by-layer film casting and interlayer crosslinking in combination with magnetic field orientation treatment. Oxygen isolation, air permeability, mechanical property and antibacterial property can be balanced by adjusting the thickness of each layer or material type according to different requirements, and multi-scene packaging requirements are met.

Description

Technical Field

[0001] This invention belongs to the field of functional packaging materials technology, specifically relating to a water-based highly active polycarbonate packaging material, its preparation method, and its application. Background Technology In the modern packaging industry, the performance of packaging materials directly determines the storage period, quality stability, and distribution safety of packaged products. This is especially true for special sectors such as high-value pharmaceuticals, precision electronic components, and perishable foods, which place extremely stringent requirements on the barrier properties (oxygen and water vapor barrier capabilities) and safety (no harmful substance residues) of packaging materials. Water-based packaging materials, due to their advantages such as using water as a dispersion medium and low volatile organic compound (VOC) emissions, are gradually replacing traditional solvent-based packaging materials and have become one of the mainstream development directions in the packaging field. However, existing water-based packaging films still face two major technological bottlenecks in practical applications, severely restricting their widespread application in demanding scenarios.

[0002] From the perspective of barrier performance, most commercially available water-based packaging films are based on single polymer emulsions. These materials contain a certain number of hydrophilic groups and micropores in their molecular chain structure, making it easy for gases (such as oxygen) and small polar molecules (such as water vapor) to pass through the film layer via molecular diffusion or pore permeation, thus failing to form an effective barrier. To improve the barrier performance of water-based packaging films, extensive research has been conducted in the existing technology field, mainly focusing on organic-inorganic composite modification and process optimization. In the area of ​​organic-inorganic composite modification, researchers have attempted to introduce inorganic barrier fillers such as montmorillonite, silica, and nano-calcium carbonate into the water-based polymer matrix, utilizing the layered structure or dense properties of the inorganic fillers to extend the gas diffusion path. However, due to the poor interfacial compatibility between montmorillonite and the waterborne polyurethane matrix, the filler is prone to agglomeration in the matrix, resulting in local defects in the film layer and failing to meet the standards for high-value products. Another study used graphene oxide as a barrier filler, whose monolayer structure has extremely high gas barrier potential. However, the surface of graphene oxide is rich in hydrophilic groups such as hydroxyl and carboxyl groups, which are prone to stacking in waterborne emulsions, making it difficult to achieve uniform dispersion. Moreover, the interfacial bonding force with the organic matrix is ​​weak, and interlayer delamination is prone to occur after film formation, which also fails to significantly improve barrier performance.

[0003] Regarding process optimization, existing technologies mostly employ traditional film-forming processes such as casting and blade coating. While these processes produce relatively dense films, they are limited by their underlying principles, resulting in unavoidable micropores within the film and hindering the directional arrangement of inorganic fillers, thus making it difficult to form continuous barrier pathways. Some studies have attempted to improve film density using hot-pressing processes, eliminating porosity through high temperature and pressure. However, waterborne polymers have poor heat resistance, and high temperatures easily lead to polymer chain degradation, which in turn reduces the film's mechanical properties and barrier stability.

[0004] In addition to insufficient barrier properties, solvent residue is another key challenge facing existing water-based packaging materials. Although water-based materials use water as the primary dispersion medium, it is still difficult to completely avoid the introduction of organic solvents in raw material preparation, modification, and film-forming processes. For food, solvent residue may alter flavor and reduce safety; for pharmaceuticals, solvents may interact with active ingredients, affecting efficacy or even producing toxic substances; for electronic components, small molecules generated by solvent evaporation may corrode component surfaces, leading to performance failure.

[0005] In summary, there is an urgent need in the current packaging materials industry for water-based packaging materials with high barrier properties. Therefore, developing a new type of water-based packaging material that can achieve high barrier properties and no solvent residue has become a key direction for promoting technological upgrading in the packaging materials field and meeting the packaging needs of high-value products. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a water-based, highly active polycarbonate packaging material.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the water-based highly active polycarbonate packaging material has a three-layer composite gradient structure, with the layers tightly bonded together by an interfacial crosslinking agent, and a total thickness of 80~120μm. Each layer includes... The inner contact layer, with a thickness of 24~36μm, is composed of 90~95 parts aliphatic polycarbonate, 0.5~1 parts nano zinc oxide, and 0.3~0.5 parts β-cyclodextrin; The middle barrier layer, with a thickness of 32~48μm, is composed of 4~6 parts montmorillonite, 1.5~2.5 parts graphene oxide, 1.5~2.5 parts layered boron nitride, 2.5~3 parts organosilane coupling agent, and 2~3 parts Fe3O4 nanoparticles. The outer protective layer, with a thickness of 24~36μm, is composed of 85~90 parts aliphatic polycarbonate, 1~1.5 parts polytetrafluoroethylene micro powder, and 0.5~1 parts UV stabilizer.

[0010] As a preferred embodiment of the water-based highly active polycarbonate packaging material of the present invention, the graphene oxide has a sheet diameter of 1~3μm and an oxygen content of 25%~30%.

[0011] As a preferred embodiment of the water-based highly active polycarbonate packaging material of the present invention, wherein the organosilane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0012] Another object of the present invention is to provide a method for preparing a water-based, highly active polycarbonate packaging material.

[0013] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including, Montmorillonite, graphene oxide, and layered boron nitride are added to the mixing tank of a high-speed disperser, and then 1 to 1.5 times the total mass of montmorillonite, graphene oxide, and layered boron nitride are added. The mixture is stirred and dispersed at 1000 to 1500 rpm for 5 to 10 minutes to form a mixed slurry. The organosilane coupling agent is mixed with 5 to 10 times the mass of deionized water, the pH is adjusted to 5 to 6, and the mixture is stirred at 500 to 800 rpm for 10 to 15 minutes to obtain the hydrolysate. The hydrolysate was slowly dripped into the mixed slurry, and the temperature was raised to 40~50℃. Fe3O4 nanoparticles were added and dispersed at high speed for 20~30 min under the condition of 2000~3000 r / min to obtain a paramagnetically treated inorganic filler slurry. Polyethylene glycol 400 was added dropwise to the inorganic filler slurry to adjust the viscosity until it reached 500-800 mPa at 25°C and 60 rpm. s, thus obtaining the middle barrier layer coating system; Aliphatic polycarbonate was emulsified to obtain a polycarbonate emulsion. Nano-zinc oxide dispersion and β-cyclodextrin were added sequentially to the polycarbonate emulsion under stirring at 800-1200 rpm, and stirring continued until homogeneous. Polyethylene glycol 400 was then added dropwise, with each drop representing 1% by mass, and allowed to stand for 2 minutes. The viscosity was measured at 25℃ and 60 rpm until the system viscosity reached 500-800 mPa. At time s, the inner contact layer coating system is obtained; Add polytetrafluoroethylene micro powder and UV stabilizer to the polycarbonate emulsion, stir for 20-25 minutes until no obvious particles remain, then add polyethylene glycol 400 dropwise, allowing it to stand for 2 minutes after each 1% by mass addition. Measure the viscosity at 25°C and 60 rpm until the system viscosity reaches 500-800 mPa. At time s, the outer protective coating system is obtained; The inner contact layer coating system, the middle barrier layer coating system, and the outer protective layer coating system are cast layer by layer to achieve interlayer cross-linking. After peeling off the film, a water-based high-activity polycarbonate packaging material with a three-layer composite gradient structure is obtained.

[0014] In a preferred embodiment of the preparation method of the water-based highly active polycarbonate packaging material of the present invention, the solid content of the polycarbonate emulsion is 45% to 55%.

[0015] In a preferred embodiment of the preparation method of the water-based highly active polycarbonate packaging material of the present invention, the solid content of the nano zinc oxide dispersion is 25-35%.

[0016] In a preferred embodiment of the preparation method of the water-based highly active polycarbonate packaging material of the present invention, the step of achieving interlayer crosslinking through layer-by-layer casting includes: The polytetrafluoroethylene (PTFE) plate is fixed horizontally, and the inner contact layer coating system is evenly cast onto the plate using a coating applicator. It is then pre-dried at room temperature until there are no obvious water stains on the film surface, thus achieving the initial film formation of the inner layer and obtaining the inner pre-cured film. A crosslinking agent is uniformly sprayed onto the surface of the inner pre-cured film. After standing to allow the crosslinking agent to penetrate, the magnetically modified middle barrier layer coating system is immediately cast onto the inner surface using a coating applicator. The coating is then dried at room temperature for 40-50 minutes to obtain the middle pre-cured film. Spray an interface crosslinking agent onto the surface of the middle layer pre-cured film. After standing, use a coater to cast the outer protective layer coating system onto the middle layer surface to ensure the film surface is flat. Heat the entire film to 60~80℃ and keep it warm for 120~180 minutes to achieve curing. During this period, the interface crosslinking agent reacts fully to achieve a tight bond between the three layers.

[0017] As a preferred embodiment of the preparation method of the water-based high-activity polycarbonate packaging material of the present invention, the magnetic modification treatment involves placing the middle barrier layer coating system in a DC magnetic field with a magnetic field strength of 1.0 to 1.5T, and keeping it at 40 to 50°C for 30 to 45 minutes. During the treatment, the mixture is stirred at a low speed of 500 to 800 rpm to ensure that all filler particles in the slurry can contact the magnetic field. After the treatment is completed, the slurry is cooled to 25 to 35°C.

[0018] Another objective of this invention is to provide an application of a water-based, highly active polycarbonate packaging material as a packaging film for high-value pharmaceuticals, precision electronic components, and perishable foods.

[0019] Beneficial effects of this invention: (1) The packaging material of the present invention is a three-layer composite gradient structure. The layers are tightly bonded by an interfacial crosslinking agent. The inner layer is based on aliphatic polycarbonate and contains nano zinc oxide and β-cyclodextrin, which have both antibacterial and compatibility properties. The middle layer is composed of montmorillonite, graphene oxide, layered boron nitride and organosilicon coupling agent, which form a continuous labyrinth barrier network through magnetic field orientation. The outer layer is based on aliphatic polycarbonate and is compounded with polytetrafluoroethylene micro powder and UV stabilizer, which has wear resistance and anti-aging properties. The functions of each component are complementary, avoiding the limitations of single modification.

[0020] (2) The present invention uses magnetic field-assisted directional film formation to guide the layered filler to oriented arrangement and form a continuous labyrinth barrier path. Combined with low temperature curing, it not only eliminates the micro-pores of the film layer, but also avoids the degradation of polymer molecular chains. Compared with traditional casting and hot pressing processes, it significantly improves the barrier stability.

[0021] (3) The water-based high-activity polycarbonate packaging material prepared by the present invention can achieve low oxygen and water vapor permeability, meet the safety requirements of food and drug packaging, provide suitable materials for high-value drugs, precision electronics and perishable food packaging, and promote the upgrading of water-based packaging materials to high-requirement scenarios. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0026] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0027] The preparation method of the 50% polycarbonate emulsion in this invention is as follows: Add 50g of aliphatic polycarbonate oligomer to a four-necked flask equipped with a stirrer and thermometer, heat to 85℃, start stirring at 300rpm, keep warm and melt for 10min until completely transparent and free of particles, slowly add 0.6g of triethylamine, increase the stirring speed to 500rpm, and continue to keep warm and stir for 5min. Take a clean beaker, add 46.7g of deionized water, 2.5g of compound emulsifier (Tween-20 1.67g + SDBS 0.83g), and 0.2g of defoamer. Heat in a 40℃ water bath and stir at 500rpm for 5 minutes until the solution is completely clear and there are no emulsifier particles remaining.

[0028] Maintain the flask temperature at 85℃ and the stirring speed at 800 rpm. Slowly drop the aqueous emulsion into the molten oligomer at a rate of 1.5 mL / min. After the addition is complete, increase the stirring speed to 1000 rpm and simultaneously cool down to 55℃ at a rate of 1℃ / min. Continue stirring for 25 min to fully disperse the oligomer, thus obtaining a polycarbonate emulsion with a solid content of 50%.

[0029] All other polycarbonate emulsions with varying solid content were prepared with adjustments made according to the same steps.

[0030] The properties of the packaging materials obtained in this application were determined using the following methods: Oxygen transmission rate was measured using an oxygen transmission rate tester at 23°C and 50% relative humidity, in accordance with ASTM D3985 standard. Water vapor transmission rate was measured at 38°C and 90% relative humidity using a water vapor transmission rate tester, in accordance with ASTM E96 standard. Tensile strength and elongation at break were measured according to GB / T1040.3-2006 standard, using a universal testing machine, dumbbell-shaped specimens, and a tensile speed of 50 mm / min.

[0031] Solvent residue was determined according to GB / T27860-2011 standard, using gas chromatography with dichloromethane as solvent and external standard method for quantification, with a detection limit ≤0.01mg / m².

[0032] The antibacterial performance was tested against Escherichia coli (ATCC25922) using the inhibition zone method, in accordance with GB / T31402-2015 standard.

[0033] The thermal decomposition temperature was determined using a thermogravimetric analyzer (TGA, such as TAQ500) at a heating rate of 10℃ / min in an air atmosphere.

[0034] Example 1 Reference Figure 1 This embodiment provides a method for preparing a water-based, highly active polycarbonate packaging material, specifically: 1) Weigh the raw materials according to the following mass proportions: Inner contact layer: 92 parts aliphatic polycarbonate (polybutylene carbonate), 0.8 parts nano zinc oxide, 0.4 parts β-cyclodextrin; Middle barrier layer: 5 parts montmorillonite, 2 parts graphene oxide (average sheet diameter 1~3μm, oxygen content 28%), 2 parts layered boron nitride, 2.8 parts organosilane coupling agent (γ-aminopropyltriethoxysilane), 2.5 parts Fe3O4 nanoparticles (average particle size 3~5nm). Outer protective layer: 88 parts aliphatic polycarbonate, 1.2 parts polytetrafluoroethylene micro powder (average particle size 1~5μm), 0.8 parts UV stabilizer (nano titanium dioxide). Interface crosslinking agent: γ-glycidoxypropyltrimethoxysilane (0.12 parts for inner layer-middle layer, 0.12 parts for middle layer-outer layer).

[0035] 2) Preparation of the intermediate barrier layer coating system: Montmorillonite, graphene oxide, and layered boron nitride were added to a high-speed disperser, along with 1.2 times the total mass of the inorganic filler in deionized water. The mixture was stirred at 1200 rpm for 8 minutes to form a slurry. An organosilane coupling agent was mixed with 8 times its mass of deionized water, and the pH was adjusted to 5.5. The mixture was then hydrolyzed at 600 rpm for 12 minutes to obtain a hydrolysate. The hydrolysate was added dropwise to the slurry, and Fe3O4 nanoparticles were added at 45℃ and 2500 rpm. The mixture was stirred for 25 minutes to obtain an inorganic filler slurry. Polyethylene glycol 400 was added dropwise to adjust the viscosity to 650 mPa. s (25℃, 60rpm), ready for use.

[0036] 3) Preparation of the inner contact layer coating system: 92 parts of aliphatic polycarbonate were emulsified to obtain a polycarbonate emulsion with a solid content of 50%; nano zinc oxide dispersion (solid content 30%) and β-cyclodextrin were added under stirring at 800 rpm and stirred for 20 min until homogeneous; polyethylene glycol 400 was added dropwise, with each 1% added and allowed to stand for 2 min, and the viscosity was measured to 700 mPa. s (25℃, 60rpm), ready for use.

[0037] 4) Preparation of the outer protective coating system: 88 parts of aliphatic polycarbonate were emulsified to obtain a polycarbonate emulsion with a solid content of 50%; polytetrafluoroethylene micro powder (pre-dispersed ultrasonically for 10 min) and UV stabilizer were added under stirring at 1000 rpm, and stirred for 22 min until no obvious particles were visible; polyethylene glycol 400 was added dropwise to adjust the viscosity to 680 mPa. s (25℃, 60rpm), ready for use.

[0038] 5) Layer-by-layer casting and cross-linking: The polytetrafluoroethylene (PTFE) sheet is fixed horizontally, and the inner coating is cast using a coater. It is then pre-dried at room temperature for 35 minutes until there are no obvious water stains (dry film thickness 30 μm). Spray 0.12 parts of interface crosslinking agent onto the inner layer surface, let stand for 5 min, and then use a coater to cast the magnetically modified intermediate layer coating onto the inner layer surface. Dry at room temperature for 45 min to obtain the intermediate layer pre-cured film (dry film thickness 40 μm). The magnetic modification treatment of the intermediate coating was carried out by applying a 1.2T DC magnetic field and holding at 45℃ for 40 minutes, during which the mixture was stirred at a low speed of 600rpm. In the middle barrier layer, silane coupling agents are introduced to functionalize the filler, improving its overall paramagnetic response. Simultaneously, Fe3O4 nanoparticles are added to form a ternary composite network of filler, coupling agent, and magnetic nanoparticles, further enhancing paramagnetism. Based on this, magnetic modification is performed. Under the influence of a magnetic field, the layered structure of the composite inorganic filler will be oriented and stacked along the magnetic field direction, forming an orderly arrangement where faces are parallel to the film surface and layers are perpendicular to the film thickness. The planar direction of the filler layers is parallel to the surface of the packaging film, and the stacking direction is consistent with the permeation direction of gas / water vapor, constructing a continuous labyrinthine barrier path. This labyrinthine barrier path has a structure similar to a layered cake plus a maze, preventing gas and water vapor from passing directly. They can only travel around the edges of the thin sheets, ultimately failing to penetrate due to the excessive length and resistance, thus achieving a high barrier effect.

[0039] Next, the magnetic field was turned off, 0.12 parts of interface crosslinking agent were sprayed onto the middle layer surface, and it was left to stand for 5 minutes. The outer layer coating was then cast and dried at 70°C for 150 minutes. After cooling to room temperature, the film was peeled off to obtain a three-layer composite packaging material with a total thickness of 100 μm.

[0040] Example 2 This embodiment provides a method for preparing a composite packaging material with high antibacterial properties. The difference from Embodiment 1 is that the raw material formulation is adjusted as follows: Inner contact layer: 92 parts aliphatic polycarbonate (polybutylene carbonate), 1 part nano zinc oxide, 0.5 parts β-cyclodextrin; Middle barrier layer: 6 parts montmorillonite, 2.5 parts graphene oxide (sheet diameter 1~3μm, oxygen content 28%), 2 parts layered boron nitride, 2.8 parts organosilane coupling agent (γ-aminopropyltriethoxysilane), 2 parts Fe3O4 nanoparticles. The thickness of the middle barrier layer was adjusted to 45 μm, and the thickness of the outer protective layer was reduced to 25 μm. The remaining steps and processes were all the same as in Example 1, resulting in the packaging film of this example.

[0041] Example 3 This embodiment provides a method for preparing a composite packaging material with high barrier properties. The difference from Embodiment 1 is that the raw material formulation is adjusted as follows: Middle barrier layer: 6 parts montmorillonite, 2.5 parts graphene oxide (sheet diameter 1~3μm, oxygen content 28%), 2 parts layered boron nitride, 3 parts organosilane coupling agent (γ-aminopropyltriethoxysilane), 3 parts Fe3O4 nanoparticles. Outer protective layer: 88 parts aliphatic polycarbonate, 1.2 parts polytetrafluoroethylene micro powder (particle size 1~5μm), 0.8 parts UV stabilizer (benzotriazole) The inner layer thickness was adjusted to 26 μm and the outer layer thickness to 30 μm; the remaining steps and processes were all the same as in Example 1, resulting in the packaging film of this example.

[0042] Example 4 This embodiment provides a method for preparing a high-strength composite packaging material, which differs from Embodiment 1 in that the raw material formulation is adjusted as follows: Outer protective layer: 85 parts aliphatic polycarbonate, 1.5 parts polytetrafluoroethylene micro powder (particle size 1~5μm), 0.8 parts UV stabilizer (nano titanium dioxide). The inner layer thickness was adjusted to 32μm, the middle layer thickness to 42μm, and the outer layer thickness to 36μm. The remaining steps and processes were the same as in Example 1, resulting in the packaging film of this example.

[0043] The properties of the packaging films prepared in Examples 1 to 4 were measured, and the results are shown in Table 1.

[0044] Table 1 As shown in Table 1, the packaging film obtained under the formulation and process conditions of this application has good comprehensive performance. By adjusting the thickness of each layer or the type of material, oxygen barrier capacity, air permeability, mechanical properties, and antibacterial properties can be flexibly balanced. For example, increasing the amount of nano zinc oxide in the inner layer can improve the antibacterial rate and make it suitable for perishable foods; thickening the middle layer or increasing the proportion of graphene oxide can enhance the barrier properties and make it suitable for high-value drugs; optimizing the ratio of polycarbonate to polytetrafluoroethylene in the outer layer can improve flexibility and make it suitable for irregularly shaped electronic components, achieving multi-scenario adaptability of one material.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that the inorganic filler (montmorillonite, graphene oxide, layered boron nitride) in the system is omitted, while the remaining steps and processes are the same as in Example 1, to obtain the packaging film of this comparative example.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that the montmorillonite in the system is replaced with layered boron nitride, while the remaining steps and processes are the same as in Example 1, to obtain the packaging film of this comparative example.

[0047] Comparative Example 3 The difference between this comparative example and Example 1 is that the graphene oxide in the system is replaced with layered boron nitride, while the remaining steps and processes are the same as in Example 1, to obtain the packaging film of this comparative example.

[0048] Comparative Example 4 The difference between this comparative example and Example 1 is that the layered boron nitride in the system is replaced with montmorillonite, while the remaining steps and processes are the same as in Example 1, resulting in the packaging film of this comparative example.

[0049] The performance of the packaging films prepared in Comparative Examples 1 to 4 was measured and compared with that in Example 1. The results are shown in Table 2.

[0050] Table 2 As shown in Table 2, the inorganic filler system has a significant impact on the performance of the prepared packaging film. This is because the aliphatic polycarbonate matrix in this application has hydrophilic groups and micropores in its molecular chains, requiring a composite inorganic filler system formed by montmorillonite, graphene oxide, and layered boron nitride to construct the barrier and reinforcement network. Omitting the inorganic filler allows oxygen and water vapor to diffuse directly through the matrix pores and intermolecular gaps, leading to a sharp drop in barrier performance. Furthermore, the disappearance of the skeletal support of the inorganic filler reduces the tensile strength of the matrix; simultaneously, the nano-zinc oxide, lacking the dispersion carrier of the inorganic filler, easily aggregates, resulting in a reduction in antibacterial active sites and an increase in solvent residue.

[0051] Specifically, montmorillonite has a high specific surface area and intercalation properties, which can fully react with organosilane coupling agents to optimize the paramagnetism of inorganic fillers and their interfacial compatibility with the matrix; graphene oxide monolayers have an atomically dense structure, which is the core barrier to block gases and water vapor, and the surface hydroxyl and carboxyl groups can strongly bind with the matrix; layered boron nitride can reduce the solubility and diffusion coefficient of gases in the filler, and can also form multi-scale layered stacks with montmorillonite and graphene oxide to extend the permeation path. Omitting any of these will greatly reduce the overall performance of the packaging film.

[0052] Comparative Example 5 The difference between this comparative example and Example 1 is that the silane coupling agent in the system is omitted, while the remaining steps and processes are the same as in Example 1, resulting in the packaging film of this comparative example.

[0053] Comparative Example 6 The difference between this comparative example and Example 1 is that the nano zinc oxide in the system is omitted, while the remaining steps and processes are the same as in Example 1, resulting in the packaging film of this comparative example.

[0054] The performance of the packaging films prepared in Comparative Examples 5 to 8 was measured and compared with that in Example 1. The results are shown in Table 3.

[0055] Table 3 As can be seen from Table 3, omitting any component in the system of this invention will significantly reduce the performance of the resulting packaging film. Specifically, the core function of the silane coupling agent in this application is to react with the hydroxyl groups on the surface of the inorganic filler at one end, enhancing the paramagnetism of the filler, and to combine with the organic matrix at the other end, improving the compatibility of the organic-inorganic interface and preventing the agglomeration of the inorganic filler. After omission, the inorganic filler agglomerates in the matrix, forming micropores through which oxygen and water vapor can quickly permeate. Under external force, the inorganic filler is easily separated from the matrix, resulting in a significant reduction in mechanical properties. Furthermore, the agglomerated inorganic filler cannot provide a uniformly dispersed carrier for other components, leading to a decrease in solvent adsorption efficiency. At the same time, the filler cannot form an ordered magnetic response network, making it impossible to subsequently optimize the structure through magnetic field control. In addition, nano-zinc oxide is the core component of the antibacterial properties of the material in the system of this invention. It achieves the antibacterial effect by releasing zinc ions to destroy the bacterial cell membrane. Omitting it drastically reduces the antibacterial properties, leaving only the physical barrier antibacterial effect of a small amount of inorganic filler.

[0056] Example 5 The difference between this embodiment and embodiment 1 is that the magnetic field strength in step 5) is adjusted to 0, 0.1T, 0.3T and 0.4T respectively. The remaining steps are the same as in embodiment 1. Packaging films under different magnetic field strength conditions are obtained in this embodiment. The relevant properties are measured and compared with those in embodiment 1. The results are shown in Table 4.

[0057] Table 4 The core function of the magnetic field orientation treatment in this invention is to utilize the weak magnetic or magnetic responsiveness of the layered inorganic fillers to guide their directional arrangement along the magnetic field direction in the coating system, forming a continuous and dense layered stacked barrier network, thus extending the permeation path of oxygen and water vapor. Without magnetic field guidance, the layered inorganic fillers are randomly dispersed in the system, with some filler stacks being discontinuous and containing pore channels, allowing for rapid permeation of oxygen and water vapor. Low magnetic fields can only partially guide the filler orientation, resulting in insufficient stacking density and the existence of a small number of dispersed gaps. Once the magnetic field strength exceeds 0.3T, the filler has achieved maximum directional arrangement; further increasing the magnetic field cannot further optimize the stacking structure and may even reduce performance.

[0058] In this application, the anisotropy coefficient (K) of the directional arrangement of the composite inorganic filler and the magnetic field parameters satisfy the following relationship: K = K0 × (B / B0) n ×exp(-E a / (R×T))×t^(1 / 2); In the formula, K represents the anisotropy coefficient of the packing orientation, ranging from 1.5 to 3.8, reflecting the degree of difference in the packing arrangement along the magnetic field direction and perpendicular to it; K0 represents the reference anisotropy coefficient, ranging from 1.2 to 1.5, characterizing the anisotropy potential of the layered structure of the packing itself; B represents the magnetic field strength, ranging from 0.1 to 0.3 T; B0 represents the reference magnetic field strength (reference value), ranging from 0.2 T; n represents the magnetic field response index, ranging from 1.8 to 2.5, which is related to the effect of magnetic modification treatment of the packing; E a The value represents the directional activation energy of the packing material, ranging from 15 to 25 kJ / mol. It reflects the energy required for the packing material to overcome agglomeration resistance and achieve directional orientation. R represents the gas constant, with a value of 8.314 J / (mol). K), T represents the magnetic field treatment temperature, with a value range of 40~50℃, and t represents the magnetic field treatment time, with a value range of 60~90min.

[0059] A larger anisotropy coefficient K indicates a more regular directional arrangement of the packing material and stronger barrier performance. When K ≥ 2.0, a continuous labyrinthine barrier network can be formed, with an oxygen permeability ≤ 5.0 cc / (m²). 24h atm) When the magnetic field strength B is in the range of 0.1 to 0.3 T, K increases exponentially with the increase of B; after exceeding 0.3 T, the increase of K tends to be gradual, and excessively high magnetic fields are prone to cause packing agglomeration, so 0.2 T is preferred. Increasing the processing temperature T enhances molecular thermal motion, which helps the filler overcome interfacial resistance and achieve orientation. However, if T > 50℃, it may lead to a decrease in the stability of the polycarbonate emulsion. Therefore, the temperature is limited to 40–50℃. As the processing time t increases, the packing orientation tends to be more perfect, but after t>90min, the increase in K is less than 5%. Considering production efficiency, 60-90min is selected.

[0060] In summary, this application achieves a breakthrough through integrated innovation of synergistic modification of composite inorganic fillers, interface optimization, magnetic field orientation, and functionalized adsorption / antibacterial properties. It employs a composite inorganic filler system composed of montmorillonite, graphene oxide, and layered boron nitride, which synergistically form a multi-scale labyrinthine barrier network. Organosilane coupling agents effectively improve the compatibility of the organic-inorganic interface, preventing filler agglomeration. The magnetic field-oriented film-forming process guides the directional arrangement of inorganic fillers, forming a continuous and dense barrier pathway. Nano-zinc oxide imparts antibacterial properties to the material. Through the synergistic effect of multiple technological features, it produces technical effects exceeding conventional expectations, solves substantial defects in existing technologies, and fully demonstrates the innovative value of this application in the field of water-based packaging materials, providing a suitable solution for the packaging needs of high-value pharmaceuticals, precision electronics, and perishable foods.

[0061] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A water-based, highly active polycarbonate packaging material, characterized in that: The water-based, highly active polycarbonate packaging material has a three-layer composite gradient structure, with the layers tightly bonded together by an interfacial crosslinking agent. The total thickness is 80-120 μm. Each layer includes… The inner contact layer, with a thickness of 24~36μm, is composed of 90~95 parts aliphatic polycarbonate, 0.5~1 parts nano zinc oxide, and 0.3~0.5 parts β-cyclodextrin; The middle barrier layer, with a thickness of 32~48μm, is composed of 4~6 parts montmorillonite, 1.5~2.5 parts graphene oxide, 1.5~2.5 parts layered boron nitride, 2.5~3 parts organosilane coupling agent, and 2~3 parts Fe3O4 nanoparticles. The outer protective layer, with a thickness of 24~36μm, is composed of 85~90 parts aliphatic polycarbonate, 1~1.5 parts polytetrafluoroethylene micro powder, and 0.5~1 parts UV stabilizer.

2. The water-based highly active polycarbonate packaging material as described in claim 1, characterized in that: The graphene oxide has a sheet diameter of 1~3μm and an oxygen content of 25%~30%.

3. The water-based highly active polycarbonate packaging material as described in claim 1, characterized in that: The organosilane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

4. A preparation method for preparing the water-based highly active polycarbonate packaging material as described in any one of claims 1-3, characterized in that: include, Montmorillonite, graphene oxide, and layered boron nitride are added to the mixing tank of a high-speed disperser, and then 1 to 1.5 times the total mass of montmorillonite, graphene oxide, and layered boron nitride are added. The mixture is stirred and dispersed at 1000 to 1500 rpm for 5 to 10 minutes to form a mixed slurry. The organosilane coupling agent is mixed with 5 to 10 times the mass of deionized water, the pH is adjusted to 5 to 6, and the mixture is stirred at 500 to 800 rpm for 10 to 15 minutes to obtain the hydrolysate. The hydrolysate was slowly dripped into the mixed slurry, and the temperature was raised to 40~50℃. Fe3O4 nanoparticles were added and dispersed at high speed for 20~30 min under the condition of 2000~3000 r / min to obtain a paramagnetically treated inorganic filler slurry. Polyethylene glycol 400 was added dropwise to the inorganic filler slurry to adjust the viscosity until it reached 500-800 mPa at 25°C and 60 rpm. s, thus obtaining the middle barrier layer coating system; Aliphatic polycarbonate was emulsified to obtain a polycarbonate emulsion. Nano-zinc oxide dispersion and β-cyclodextrin were added sequentially to the polycarbonate emulsion under stirring at 800-1200 rpm, and stirring continued until homogeneous. Polyethylene glycol 400 was then added dropwise, with each drop representing 1% by mass, and allowed to stand for 2 minutes. The viscosity was measured at 25℃ and 60 rpm until the system viscosity reached 500-800 mPa. At time s, the inner contact layer coating system is obtained; Add polytetrafluoroethylene micro powder and UV stabilizer to the polycarbonate emulsion, stir for 20-25 minutes until no obvious particles remain, then add polyethylene glycol 400 dropwise, allowing it to stand for 2 minutes after each 1% by mass addition. Measure the viscosity at 25°C and 60 rpm until the system viscosity reaches 500-800 mPa. At time s, the outer protective coating system is obtained; The inner contact layer coating system, the middle barrier layer coating system, and the outer protective layer coating system are cast layer by layer to achieve interlayer cross-linking. After peeling off the film, a water-based high-activity polycarbonate packaging material with a three-layer composite gradient structure is obtained.

5. The method for preparing the water-based highly active polycarbonate packaging material as described in claim 4, characterized in that: The solid content of the polycarbonate emulsion is 45% to 55%.

6. The method for preparing the water-based highly active polycarbonate packaging material as described in claim 4, characterized in that: The solid content of the nano zinc oxide dispersion is 25-35%.

7. The method for preparing the water-based highly active polycarbonate packaging material as described in claim 4, characterized in that: The step of layer-by-layer casting to achieve interlayer crosslinking includes, The polytetrafluoroethylene (PTFE) plate is fixed horizontally, and the inner contact layer coating system is evenly cast onto the plate using a coating applicator. It is then pre-dried at room temperature until there are no obvious water stains on the film surface, thus achieving the initial film formation of the inner layer and obtaining the inner pre-cured film. A crosslinking agent is uniformly sprayed onto the surface of the inner pre-cured film. After standing to allow the crosslinking agent to penetrate, the magnetically modified middle barrier layer coating system is immediately cast onto the inner surface using a coating applicator. The coating is then dried at room temperature for 40-50 minutes to obtain the middle pre-cured film. Spray an interface crosslinking agent onto the surface of the middle layer pre-cured film. After standing, use a coater to cast the outer protective layer coating system onto the middle layer surface to ensure the film surface is flat. Heat the entire film to 60~80℃ and keep it warm for 120~180 minutes to achieve curing. During this period, the interface crosslinking agent reacts fully to achieve a tight bond between the three layers.

8. The method for preparing the water-based highly active polycarbonate packaging material as described in claim 7, characterized in that: The magnetic modification treatment involves placing the middle barrier layer coating system in a DC magnetic field with a magnetic field strength of 1.0 to 1.5T and keeping it at 40 to 50°C for 30 to 45 minutes. During the treatment, the mixture is stirred at a low speed of 500 to 800 rpm to ensure that all filler particles in the slurry can come into contact with the magnetic field. After the treatment is completed, the slurry is cooled to 25 to 35°C.

9. The application of the water-based high-activity polycarbonate packaging material as described in any one of claims 1 to 3 as a packaging film for high-value pharmaceuticals, precision electronic components, and perishable foods.

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