High-barrier composite packaging film and preparation method thereof

Abstract

The invention relates to the field of packaging materials, in particular to a high-barrier composite packaging film and a preparation method thereof, and solves the problems that an existing composite film is unstable in performance and cannot meet the requirements for high strength and high barrier performance. The high-barrier composite packaging film has unique structural design, the modified polyethylene in the core layer serves as an excellent base material, the mechanical strength and durability of the film are improved, and the mechanical property and thermal stability of the film are further improved by adding the modified one-dimensional filler; polyamide in the outer layer can effectively prevent permeation of water vapor and oxygen due to high temperature resistance and good water vapor barrier property, the hydrophobicity of the film is enhanced by adding the modified composite two-dimensional filler, the film can be endowed with excellent barrier property, and meanwhile, the mechanical property of the film can be further improved; the high-barrier and high-mechanical-property composite packaging film is successfully prepared, is suitable for high-barrier packaging requirements in multiple fields, and has important industrial application value and market prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of packaging materials, in particular to a high-barrier composite packaging film and a preparation method thereof. BACKGROUND

[0002] In modern society, packaging films play an important role in many fields such as food, medicine, electronics, etc. However, traditional packaging films are mostly single-layer structures, which often cannot meet the high barrier requirements of moisture, gas and other external factors, leading to product deterioration during storage. In order to solve this problem, a composite film structure with high barrier properties can effectively improve the overall barrier performance of the film, thereby prolonging the shelf life of the packaged product and improving its market competitiveness. However, the existing composite films have poor interlayer adhesion, poor compatibility of the fillers added inside, and are prone to delamination, resulting in unstable performance of the composite film and failing to meet the requirements of high strength and high barrier performance. Therefore, it is of great practical significance to develop a high-barrier composite packaging film and a preparation method thereof.

[0003] In view of the above technical defects, a solution is proposed. SUMMARY

[0004] In order to overcome the above technical problems, the purpose of the present application is to provide a high-barrier composite packaging film and a preparation method thereof, which solves the problem of unstable performance of the existing composite film and fails to meet the requirements of high strength and high barrier performance.

[0005] The purpose of the present application can be achieved by the following technical solutions: In a first aspect, the present application provides a high-barrier composite packaging film, comprising a core layer and outer layers on both sides of the core layer; the thickness of the core layer is 20-25 μm; the thickness of the outer layer is 3-5 μm; The core layer comprises the following components by weight: 90-95 parts of modified polyethylene, 0.8-4.2 parts of modified one-dimensional filler; The outer layer comprises the following components by weight: 90-95 parts of polyamide, 3-9 parts of modified composite two-dimensional filler, 0.8-1.6 parts of nucleating agent and 0.5-0.9 parts of antioxidant; The modified polyethylene is prepared by the following steps: The polyethylene, glycidyl methacrylate, di-tert-butyl peroxide isopropyl benzene and antioxidant 1010 are added into a double screw extruder, and melt extruded under the conditions of temperature 150-190℃ and screw rotation speed 30-50r / min, and then cooled and cut into particles, and the formed particles are poured into xylene and soaked for 8-10h, and then vacuum filtered, and the filter cake is washed with acetone for 3-5 times, and then placed in a vacuum drying oven and dried at temperature 50-60℃ for 6-8h to obtain the modified polyethylene.

[0006] As a preferred embodiment of the present application, the polyethylene, glycidyl methacrylate, di-tert-butyl peroxide isopropyl benzene and antioxidant 1010 are used in a ratio of 10g:0.1-0.9g:0.01-0.03g:0.01-0.02g; and the polyethylene is LLDPE DFDA-7042.

[0007] As a preferred embodiment of the present application, the modified one-dimensional filler is prepared by the following steps: The carbon fiber is added into a hydrochloric acid solution and soaked for 2-6h, and then taken out and added into a three-necked flask equipped with a stirrer and a thermometer, and then silane coupling agent KH-560, anhydrous ethanol and deionized water are added and stirred at temperature 20-25℃ and stirring speed 200-300r / min for 10-20min, and then the temperature is increased to 70-80℃ and the stirring is continued for 4-6h, and after the reaction is completed, the reaction product is vacuum filtered, the filter cake is washed with distilled water for 3-5 times, and then placed in a vacuum drying oven and dried at temperature 60-70℃ for 3-5h to obtain the modified one-dimensional filler.

[0008] As a preferred embodiment of the present application, the carbon fiber, hydrochloric acid solution, silane coupling agent KH-560, anhydrous ethanol and deionized water are used in a ratio of 2g:20-30mL:0.5-2.5g:50-55mL:10-12mL; the carbon fiber is Toray T300 3K carbon fiber; and the molar concentration of the hydrochloric acid solution is 1-2mol / L.

[0009] As a preferred embodiment of the present application, the modified composite two-dimensional filler is prepared by the following steps: Step a1: graphene oxide, deionized water were added into a reaction kettle, nitrogen was introduced for protection, stirring was carried out at a temperature of 20-25℃ and a stirring rate of 200-300r / min for 30-60min, then ammonium molybdate and sodium sulfide were added and stirring was continued for 30-60min, then hydrazine hydrate solution was added and stirring was continued for 20-30min, then the temperature was raised to 160-180℃ and hydrothermal reaction was carried out for 20-30h, after the reaction was completed, the reaction product was cooled to room temperature, then centrifugation was carried out, the precipitate was washed with distilled water and anhydrous ethanol for 3-5 times, then it was placed in a vacuum drying oven and dried at a temperature of 70-80℃ for 3-5h, to obtain a composite two-dimensional filler; Step a2: 3-chloropropyl triethoxysilane, 3,5-di(trifluoromethyl)aniline, anhydrous potassium carbonate, potassium iodide and anhydrous toluene were added into a three-necked flask equipped with a stirrer, a thermometer and a gas inlet tube, nitrogen was introduced for protection, stirring was carried out at a temperature of 0-5℃ and a stirring rate of 200-300r / min for 20-30min, then the temperature was raised to 80-90℃ and stirring was continued for 20-30h, after the reaction was completed, the reaction product was vacuum filtered, the filtrate was rotary evaporated to remove the solvent, then it was placed in a vacuum drying oven and dried at a temperature of 50-60℃ for 5-6h, to obtain a fluorine-containing siloxane; Step a3: the fluorine-containing siloxane, anhydrous ethanol and deionized water were added into a three-necked flask equipped with a stirrer, a thermometer and a gas inlet tube, nitrogen was introduced for protection, stirring was carried out at a temperature of 20-25℃ and a stirring rate of 200-300r / min for 20-30min, then the composite two-dimensional filler was added and the temperature was raised to 70-80℃ and stirring was continued for 6-8h, after the reaction was completed, the reaction product was vacuum filtered, the filter cake was washed with distilled water for 3-5 times, then it was placed in a vacuum drying oven and dried at a temperature of 50-60℃ for 3-5h, to obtain a modified composite two-dimensional filler.

[0010] As a preferred embodiment of the present application, the amount ratio of the graphene oxide, deionized water, ammonium molybdate, sodium sulfide and hydrazine hydrate solution in step a1 is 0.1-0.5g:20-25mL:1g:1g:2-3mL; the mass fraction of the hydrazine hydrate solution is 30-50%.

[0011] As a preferred embodiment of the present application, the amount ratio of the 3-chloropropyl triethoxysilane, 3,5-di(trifluoromethyl)aniline, anhydrous potassium carbonate, potassium iodide and anhydrous toluene in step a2 is 10mmol:10mmol:30-40mmol:1-1.5mmol:50-60mL.

[0012] In a preferred embodiment of the present invention, the ratio of the amount of fluorinated siloxane, anhydrous ethanol, deionized water and composite two-dimensional filler in step a3 is 0.8-1.6g: 50-55mL: 8-10mL: 2g.

[0013] Secondly, this application provides a method for preparing a high-barrier composite packaging film, comprising the following steps: Step 1: Weigh 90-95 parts of modified polyethylene and 0.8-4.2 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step 2: Weigh out 90-95 parts of polyamide, 3-9 parts of modified composite two-dimensional filler, 0.8-1.6 parts of nucleating agent and 0.5-0.9 parts of antioxidant according to the weight ratio to obtain the outer layer raw material; Step 3: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt-extrude them into the three-layer die at a temperature of 240-260℃ and a screw speed of 50-70r / min to form a three-layer thick sheet; Step 4: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and another outer layer from top to bottom.

[0014] In a preferred embodiment of the present invention, the polyamide is PA6 1022B; The nucleating agent is talc powder with an average particle size of 5 μm; The antioxidant is antioxidant 1010.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a high-barrier composite packaging film and its preparation method. The high-barrier composite packaging film has a unique structural design, including a core layer and outer layers on both sides of the core layer. Modified polyethylene in the core layer serves as an excellent substrate, improving the mechanical strength and durability of the film. The addition of modified one-dimensional fillers further enhances the mechanical properties and thermal stability of the film. Polyamide in the outer layer, due to its high temperature resistance and good water vapor barrier properties, can effectively prevent the penetration of water vapor and oxygen. The addition of modified composite two-dimensional fillers enhances the hydrophobicity of the film and imparts excellent barrier properties, while also further improving the mechanical properties of the film. A high-barrier, high-mechanical-performance composite packaging film has been successfully prepared, suitable for high-barrier packaging needs in multiple fields, and has significant industrial application value and market prospects.

[0016] In the preparation of high-barrier composite packaging film, a modified polyethylene and a modified one-dimensional filler were first prepared. Glycidyl methacrylate was grafted into the polyethylene molecular chain using a grafting reaction, introducing a large number of epoxy groups, which effectively improved the compatibility between polyethylene and the modified one-dimensional filler, and also enhanced the interfacial bonding force between the outer layer and the core layer. The carbon fiber was modified using the silane coupling agent KH-560. The siloxane groups on the silane coupling agent KH-560 hydrolyzed to form silanols, which could be grafted onto the surface of the carbon fiber, while introducing a large number of silicon atoms and epoxy groups. This allowed the carbon fiber to be evenly distributed in the polyethylene and connected by chemical bonds, enhancing the bonding force between the two. Finally, the high-barrier composite packaging film was endowed with excellent mechanical properties.

[0017] In the process of preparing high-barrier composite packaging film, a modified composite two-dimensional filler was also prepared. Molybdenum disulfide was coated onto the surface of graphene oxide as a core to obtain the composite two-dimensional filler. The chlorine atoms on 3-chloropropyltriethoxysilane react with the amino groups on 3,5-bis(trifluoromethyl)aniline to introduce a large number of fluorine atoms, resulting in a fluorinated siloxane. The fluorinated siloxane was used to modify the composite two-dimensional filler. The siloxane groups on the fluorinated siloxane hydrolyzed to form silanols, which could be grafted onto the surface of the composite two-dimensional filler. Simultaneously, a large number of silicon and fluorine atoms were introduced, allowing the composite two-dimensional filler to be uniformly distributed in the polyamide. The composite two-dimensional filler utilizes its layered structure to form a physical barrier, giving it excellent barrier properties. The introduced fluorine atoms significantly improve its hydrophobicity, effectively inhibiting water wetting and blocking water penetration, further enhancing its barrier properties. At the same time, the composite two-dimensional filler has excellent mechanical properties, which can further improve the mechanical properties of the composite packaging film. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1:

[0019] This embodiment describes a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: 10g of polyethylene LLDPE DFDA-7042, 0.1g of glycidyl methacrylate, 0.01g of di-tert-butylperoxyisopropylbenzene, and 0.01g of antioxidant 1010 were added to a twin-screw extruder and melt-extruded at a temperature of 150℃ and a screw speed of 30r / min. After cooling and pelleting, the resulting pellets were soaked in xylene for 8 hours, then vacuum filtered. The filter cake was washed three times with acetone and then placed in a vacuum drying oven and dried at a temperature of 50℃ for 6 hours to obtain modified polyethylene. Step S2: Add 2g of Toray T300 3K carbon fiber to 20mL of 1mol / L hydrochloric acid solution and soak for 2h. Then take it out and add it to a three-necked flask equipped with a stirrer and thermometer. Then add 0.5g of silane coupling agent KH-560, 50mL of anhydrous ethanol and 10mL of deionized water and stir for 10min at 20℃ and 200r / min. Then raise the temperature to 70℃ and continue stirring for 4h. After the reaction is completed, the reaction product is vacuum filtered. The filter cake is washed 3 times with distilled water and then placed in a vacuum drying oven and dried at 60℃ for 3h to obtain the modified one-dimensional filler. Step S3: Add 0.1g of graphene oxide and 20mL of deionized water to the reaction vessel, purge with nitrogen for protection, and stir for 30min at 20℃ and 200r / min. Then add 1g of ammonium molybdate and 1g of sodium sulfide and continue stirring for 30min. Then add 2mL of 30% hydrazine hydrate solution and continue stirring for 20min. Then raise the temperature to 160℃ and hydrothermally react for 20h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate three times with distilled water and anhydrous ethanol, then place it in a vacuum drying oven and dry at 70℃ for 3h to obtain the composite two-dimensional filler. Step S4: 10 mmol of 3-chloropropyltriethoxysilane, 10 mmol of 3,5-bis(trifluoromethyl)aniline, 30 mmol of anhydrous potassium carbonate, 1 mmol of potassium iodide and 50 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 0 °C and 200 r / min for 20 min. Then the temperature was raised to 80 °C and the mixture was stirred for 20 h. After the reaction was completed, the reaction product was vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then placed in a vacuum drying oven and dried at 50 °C for 5 h to obtain fluorosiloxane. Step S5: Add 0.8g of fluorosiloxane, 50mL of anhydrous ethanol and 8mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir for 20min at 20℃ and 200r / min. Then add 2g of composite two-dimensional filler and continue stirring for 6h at 70℃. After the reaction is complete, vacuum filter the reaction product, wash the filter cake three times with distilled water, and then place it in a vacuum drying oven and dry at 50℃ for 3h to obtain the modified composite two-dimensional filler. Step S6: Weigh 90 parts of modified polyethylene and 0.8 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step S7: Weigh 90 parts of polyamide, 3 parts of modified composite two-dimensional filler, 0.8 parts of nucleating agent, and 0.5 parts of antioxidant according to the following weight proportions to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010; Step S8: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 240℃ and a screw speed of 50r / min to form a three-layer thick sheet; Step S9: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm. Example 2:

[0020] This embodiment describes a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: 10g of polyethylene LLDPE DFDA-7042, 0.5g of glycidyl methacrylate, 0.02g of di-tert-butylperoxyisopropylbenzene, and 0.015g of antioxidant 1010 were added to a twin-screw extruder and melt-extruded at a temperature of 170℃ and a screw speed of 40r / min. After cooling and pelleting, the resulting pellets were soaked in xylene for 9h, then vacuum filtered. The filter cake was washed four times with acetone and then placed in a vacuum drying oven and dried at a temperature of 55℃ for 7h to obtain modified polyethylene. Step S2: 2g of Toray T300 3K carbon fiber was added to 25mL of hydrochloric acid solution with a molar concentration of 1.5mol / L and soaked for 4h. Then, it was taken out and added to a three-necked flask equipped with a stirrer and thermometer. Then, 1.5g of silane coupling agent KH-560, 52mL of anhydrous ethanol and 11mL of deionized water were added and stirred at 22℃ and 250r / min for 15min. Then, the temperature was raised to 75℃ and the stirring was continued for 5h. After the reaction was completed, the reaction product was vacuum filtered. The filter cake was washed 4 times with distilled water and then placed in a vacuum drying oven and dried at 65℃ for 4h to obtain the modified one-dimensional filler. Step S3: Add 0.3g of graphene oxide and 22mL of deionized water to the reaction vessel, purge with nitrogen for protection, and stir for 40min at 22℃ and 250r / min. Then add 1g of ammonium molybdate and 1g of sodium sulfide and continue stirring for 40min. Then add 2.5mL of 40% hydrazine hydrate solution and continue stirring for 25min. Then raise the temperature to 170℃ and hydrothermally react for 25h. After the reaction is completed, cool the reaction product to room temperature, centrifuge, and wash the precipitate four times with distilled water and anhydrous ethanol. Then place it in a vacuum drying oven and dry at 75℃ for 4h to obtain the composite two-dimensional filler. Step S4: 10 mmol of 3-chloropropyltriethoxysilane, 10 mmol of 3,5-bis(trifluoromethyl)aniline, 35 mmol of anhydrous potassium carbonate, 1.3 mmol of potassium iodide, and 55 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 3°C ​​and 250 r / min for 25 min. The mixture was then heated to 85°C and stirred for another 25 h. After the reaction was completed, the product was vacuum filtered, and the solvent was removed by rotary evaporation. The filtrate was then placed in a vacuum drying oven and dried at 55°C for 5.5 h to obtain fluorosiloxane. Step S5: Add 1.2g of fluorosiloxane, 52mL of anhydrous ethanol and 9mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir for 25min at 22℃ and 250r / min. Then add 2g of composite two-dimensional filler and continue stirring for 7h at 75℃. After the reaction is complete, filter the reaction product under vacuum. Wash the filter cake 4 times with distilled water and then place it in a vacuum drying oven and dry at 55℃ for 4h to obtain the modified composite two-dimensional filler. Step S6: Weigh 92 parts of modified polyethylene and 2.5 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step S7: Weigh 92 parts of polyamide, 6 parts of modified composite two-dimensional filler, 1.2 parts of nucleating agent, and 0.7 parts of antioxidant according to the weight ratio to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010; Step S8: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 250℃ and a screw speed of 60r / min to form a three-layer thick sheet; Step S9: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm. Example 3:

[0021] This embodiment describes a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: 10g of polyethylene LLDPE DFDA-7042, 0.9g of glycidyl methacrylate, 0.03g of di-tert-butylperoxyisopropylbenzene, and 0.02g of antioxidant 1010 were added to a twin-screw extruder and melt-extruded at a temperature of 190℃ and a screw speed of 50r / min. After cooling and pelleting, the resulting pellets were soaked in xylene for 10h, then vacuum filtered. The filter cake was washed 5 times with acetone and then placed in a vacuum drying oven and dried at a temperature of 60℃ for 8h to obtain modified polyethylene. Step S2: 2g of Toray T300 3K carbon fiber was added to 30mL of 2mol / L hydrochloric acid solution and soaked for 6h. Then, it was taken out and added to a three-necked flask equipped with a stirrer and thermometer. Then, 2.5g of silane coupling agent KH-560, 55mL of anhydrous ethanol and 12mL of deionized water were added and stirred at 25℃ and 300r / min for 20min. Then, the temperature was raised to 80℃ and the stirring was continued for 6h. After the reaction was completed, the reaction product was vacuum filtered. The filter cake was washed 5 times with distilled water and then placed in a vacuum drying oven and dried at 70℃ for 5h to obtain the modified one-dimensional filler. Step S3: Add 0.5g of graphene oxide and 25mL of deionized water to the reaction vessel, purge with nitrogen for protection, and stir for 60min at 25℃ and 300r / min. Then add 1g of ammonium molybdate and 1g of sodium sulfide and continue stirring for 60min. Then add 3mL of 50% hydrazine hydrate solution and continue stirring for 30min. Then heat to 180℃ and hydrothermally react for 30h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and wash the precipitate five times with distilled water and anhydrous ethanol. Then place it in a vacuum drying oven and dry at 80℃ for 5h to obtain the composite two-dimensional filler. Step S4: 10 mmol of 3-chloropropyltriethoxysilane, 10 mmol of 3,5-bis(trifluoromethyl)aniline, 40 mmol of anhydrous potassium carbonate, 1.5 mmol of potassium iodide, and 60 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 5 °C and a stirring rate of 300 r / min for 30 min. Then, the temperature was raised to 90 °C and the mixture was stirred for another 30 h. After the reaction was completed, the reaction product was vacuum filtered, and the solvent was removed by rotary evaporation. The filtrate was then placed in a vacuum drying oven and dried at 60 °C for 6 h to obtain fluorosiloxane. Step S5: Add 1.6g of fluorosiloxane, 55mL of anhydrous ethanol and 10mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 25℃ and 300r / min for 30min. Then add 2g of composite two-dimensional filler and continue stirring at 80℃ for 8h. After the reaction is complete, vacuum filter the reaction product. Wash the filter cake 5 times with distilled water and then place it in a vacuum drying oven and dry at 60℃ for 5h to obtain the modified composite two-dimensional filler. Step S6: Weigh 95 parts of modified polyethylene and 4.2 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step S7: Weigh 95 parts of polyamide, 9 parts of modified composite two-dimensional filler, 1.6 parts of nucleating agent, and 0.9 parts of antioxidant according to the following weight proportions to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010; Step S8: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 260℃ and a screw speed of 70r / min to form a three-layer thick sheet; Step S9: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm.

[0022] Comparative Example 1: This comparative example illustrates a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: Weigh polyethylene to obtain core layer raw material; the polyethylene is LLDPE DFDA-7042; Step S2: Weigh 95 parts of polyamide, 1.6 parts of nucleating agent, and 0.9 parts of antioxidant according to the specified weight to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010. Step S3: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 260℃ and a screw speed of 70r / min to form a three-layer thick sheet; Step S4: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm.

[0023] Comparative Example 2: This comparative example illustrates a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: 10g of polyethylene LLDPE DFDA-7042, 0.9g of glycidyl methacrylate, 0.03g of di-tert-butylperoxyisopropylbenzene, and 0.02g of antioxidant 1010 were added to a twin-screw extruder and melt-extruded at a temperature of 190℃ and a screw speed of 50r / min. After cooling and pelleting, the resulting pellets were soaked in xylene for 10h, then vacuum filtered. The filter cake was washed 5 times with acetone and then placed in a vacuum drying oven and dried at a temperature of 60℃ for 8h to obtain modified polyethylene. Step S2: 2g of Toray T300 3K carbon fiber was added to 30mL of 2mol / L hydrochloric acid solution and soaked for 6h. Then, it was taken out and added to a three-necked flask equipped with a stirrer and thermometer. Then, 2.5g of silane coupling agent KH-560, 55mL of anhydrous ethanol and 12mL of deionized water were added and stirred at 25℃ and 300r / min for 20min. Then, the temperature was raised to 80℃ and the stirring was continued for 6h. After the reaction was completed, the reaction product was vacuum filtered. The filter cake was washed 5 times with distilled water and then placed in a vacuum drying oven and dried at 70℃ for 5h to obtain the modified one-dimensional filler. Step S3: Weigh 95 parts of modified polyethylene and 4.2 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step S4: Weigh 95 parts of polyamide, 1.6 parts of nucleating agent, and 0.9 parts of antioxidant according to the specified weight to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010. Step S5: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 260℃ and a screw speed of 70r / min to form a three-layer thick sheet; Step S6: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and another outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm.

[0024] Comparative Example 3: This comparative example illustrates a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: Add 0.5g of graphene oxide and 25mL of deionized water to the reaction vessel, purge with nitrogen for protection, and stir for 60min at 25℃ and 300r / min. Then add 1g of ammonium molybdate and 1g of sodium sulfide and continue stirring for 60min. Then add 3mL of 50% hydrazine hydrate solution and continue stirring for 30min. Then heat to 180℃ and hydrothermally react for 30h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and wash the precipitate five times with distilled water and anhydrous ethanol. Then place it in a vacuum drying oven and dry at 80℃ for 5h to obtain the composite two-dimensional filler. Step S2: 10 mmol of 3-chloropropyltriethoxysilane, 10 mmol of 3,5-bis(trifluoromethyl)aniline, 40 mmol of anhydrous potassium carbonate, 1.5 mmol of potassium iodide and 60 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 5 °C and 300 r / min for 30 min. Then the temperature was raised to 90 °C and the mixture was stirred for 30 h. After the reaction was completed, the reaction product was filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then placed in a vacuum drying oven and dried at 60 °C for 6 h to obtain fluorosiloxane. Step S3: Add 1.6g of fluorosiloxane, 55mL of anhydrous ethanol and 10mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 25℃ and 300r / min for 30min. Then add 2g of composite two-dimensional filler and continue stirring at 80℃ for 8h. After the reaction is complete, vacuum filter the reaction product, wash the filter cake 5 times with distilled water, and then place it in a vacuum drying oven and dry at 60℃ for 5h to obtain the modified composite two-dimensional filler. Step S4: Weigh polyethylene to obtain core layer raw material; the polyethylene is LLDPE DFDA-7042; Step S5: Weigh 95 parts of polyamide, 9 parts of modified composite two-dimensional filler, 1.6 parts of nucleating agent, and 0.9 parts of antioxidant according to the weight ratio to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010; Step S6: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 260℃ and a screw speed of 70r / min to form a three-layer thick sheet; Step S7: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the thickness of the core layer is 25 μm; and the thickness of the outer layer is 5 μm.

[0025] Comparative Example 4: This comparative example illustrates a method for preparing a high-barrier composite packaging film, comprising the following steps: Step S1: Weigh 95 parts of polyethylene and 4.2 parts of carbon fiber according to the weight ratio to obtain the core layer raw material; the polyethylene is LLDPE DFDA-7042; the carbon fiber is Toray T300 3K carbon fiber; Step S2: Weigh out 95 parts of polyamide, 9 parts of molybdenum disulfide, 1.6 parts of nucleating agent, and 0.9 parts of antioxidant according to the following weight proportions to obtain the outer layer raw material; the polyamide is PA6 1022B; the nucleating agent is talc powder with an average particle size of 5μm; the antioxidant is antioxidant 1010; Step S3: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt extrude them into the three-layer die at a temperature of 260℃ and a screw speed of 70r / min to form a three-layer thick sheet; Step S4: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and an outer layer from top to bottom; the core layer has a thickness of 25 μm; and the outer layer has a thickness of 5 μm.

[0026] The performance of the high-barrier composite packaging films of Examples 1-3 and Comparative Examples 1-4 was tested, and the test results are shown in the table below:

[0027] Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-4, it can be seen that the composite packaging film of this application has excellent mechanical properties and barrier properties.

[0028] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A high-barrier composite packaging film, characterized in that, It includes a core layer and outer layers on both sides of the core layer; the thickness of the core layer is 20-25 μm; the thickness of the outer layers is 3-5 μm; The core layer comprises the following components in parts by weight: 90-95 parts modified polyethylene, 0.8-4.2 parts modified one-dimensional filler; The outer layer comprises the following components in parts by weight: The mixture contains 90-95 parts polyamide, 3-9 parts modified composite two-dimensional filler, 0.8-1.6 parts nucleating agent, and 0.5-0.9 parts antioxidant. The modified polyethylene is prepared by the following steps: Polyethylene, glycidyl methacrylate, di-tert-butylperoxyisopropylbenzene, and antioxidant 1010 were melt-extruded, cooled, and pelletized. The resulting pellets were then soaked in xylene, vacuum filtered, and the filter cake was washed and dried to obtain modified polyethylene.

2. The high-barrier composite packaging film according to claim 1, characterized in that, The ratio of polyethylene, glycidyl methacrylate, di-tert-butylperoxyisopropylbenzene, and antioxidant 1010 is 10g:0.1-0.9g:0.01-0.03g:0.01-0.02g; the polyethylene is LLDPE DFDA-7042.

3. The high-barrier composite packaging film according to claim 1, characterized in that, The modified one-dimensional filler is prepared by the following steps: Carbon fibers were soaked in hydrochloric acid solution, then removed and silane coupling agent KH-560, anhydrous ethanol and deionized water were added and stirred to react. After the reaction was completed, the reaction product was vacuum filtered, and the filter cake was washed and dried to obtain the modified one-dimensional filler.

4. The high-barrier composite packaging film according to claim 3, characterized in that, The ratio of carbon fiber, hydrochloric acid solution, silane coupling agent KH-560, anhydrous ethanol, and deionized water is 2g:20-30mL:0.5-2.5g:50-55mL:10-12mL; the carbon fiber is Toray T300 3K carbon fiber; and the molar concentration of the hydrochloric acid solution is 1-2mol / L.

5. The high-barrier composite packaging film according to claim 1, characterized in that, The modified composite two-dimensional filler is prepared by the following steps: Step a1: Graphene oxide and deionized water were stirred and reacted. Then, ammonium molybdate, sodium sulfide and hydrazine hydrate solution were added and stirred and reacted again. After the reaction was completed, the reaction product was cooled, centrifuged, and the precipitate was washed and dried to obtain the composite two-dimensional filler. Step a2: 3-chloropropyltriethoxysilane, 3,5-bis(trifluoromethyl)aniline, anhydrous potassium carbonate, potassium iodide and anhydrous toluene are stirred and reacted. After the reaction is completed, the reaction product is filtered under vacuum, the filtrate is evaporated by rotary evaporation and then dried to obtain fluorosiloxane. Step a3: Fluorosiloxane, anhydrous ethanol and deionized water are stirred and reacted. Then, composite two-dimensional packing is added and the reaction is stirred and reacted. After the reaction is completed, the reaction product is vacuum filtered, and the filter cake is washed and dried to obtain the modified composite two-dimensional packing.

6. The high-barrier composite packaging film according to claim 5, characterized in that, The ratio of graphene oxide, deionized water, ammonium molybdate, sodium sulfide, and hydrazine hydrate solution in step a1 is 0.1-0.5g: 20-25mL: 1g: 1g: 2-3mL; the mass fraction of the hydrazine hydrate solution is 30-50%.

7. A high-barrier composite packaging film according to claim 5, characterized in that, The ratio of 3-chloropropyltriethoxysilane, 3,5-bis(trifluoromethyl)aniline, anhydrous potassium carbonate, potassium iodide and anhydrous toluene in step a2 is 10 mmol: 10 mmol: 30-40 mmol: 1-1.5 mmol: 50-60 mL.

8. A high-barrier composite packaging film according to claim 5, characterized in that, The ratio of the amount of fluorinated siloxane, anhydrous ethanol, deionized water and composite two-dimensional filler in step a3 is 0.8-1.6g: 50-55mL: 8-10mL: 2g.

9. A method for preparing a high-barrier composite packaging film as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Weigh 90-95 parts of modified polyethylene and 0.8-4.2 parts of modified one-dimensional filler according to the weight ratio to obtain the core layer raw material; Step 2: Weigh out 90-95 parts of polyamide, 3-9 parts of modified composite two-dimensional filler, 0.8-1.6 parts of nucleating agent and 0.5-0.9 parts of antioxidant according to the weight ratio to obtain the outer layer raw material; Step 3: Add the outer layer material, core layer material and outer layer material to three different extruders, and melt-extrude them into the three-layer die at a temperature of 240-260℃ and a screw speed of 50-70r / min to form a three-layer thick sheet; Step 4: Cool and stretch the three-layer thick film to obtain a high-barrier composite packaging film consisting of an outer layer, a core layer, and another outer layer from top to bottom.

10. The method for preparing a high-barrier composite packaging film according to claim 9, characterized in that, The polyamide is PA6 1022B; The nucleating agent is talc powder with an average particle size of 5 μm; The antioxidant is antioxidant 1010.

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