Nanoparticle modified antibacterial packaging film and preparation method thereof

Abstract

The invention discloses a nanoparticle modified antibacterial packaging film and a preparation method thereof, and relates to the technical field of packaging materials. When the nano particle modified antibacterial packaging film is prepared, nano graphene sequentially reacts with 2-(2-chloroethyl) furan and 1, 2-benzisothiazole-3-ketone, and modified nano graphene is prepared; the preparation method comprises the following steps: reacting barbaloin with 2-chloro-4, 6-bis (oxyalkan-2-yl methoxy)-1, 3, 5-triazine to obtain functionalized barbaloin; the preparation method comprises the following steps: sequentially reacting linear low-density polyethylene with dimethyl allyl phosphate and 3-mercapto-1-propanol to prepare modified polyethylene; uniformly mixing the modified polyethylene, the functionalized barbaloin and the modified nano graphene, and carrying out tape casting to obtain a polyethylene film material; and coating the fluorine-containing coating liquid on the surface of a polyethylene film material to prepare the nano particle modified antibacterial packaging film. The nano particle modified antibacterial packaging film prepared by the invention has excellent antibacterial, flame-retardant, water vapor barrier and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, in particular to a nanoparticle-modified antibacterial packaging film and a preparation method thereof. Background Art

[0002] Polyethylene (PE) is one of the most widely used flexible packaging materials worldwide. Polyethylene is non-toxic, odorless, and offers excellent transparency, flexibility, and affordability, making it widely used in the chemical, food, agricultural, and packaging industries. The water vapor barrier properties of packaging materials are crucial for the preservation of products such as food and pharmaceuticals. Water vapor permeation can cause moisture, softening, and microbial growth, accelerating spoilage, and can also render pharmaceuticals ineffective. With increasing demands for water vapor barrier properties in the food and pharmaceutical sectors, further improving the water vapor barrier properties of polyethylene has become a pressing issue. Nanographene, a two-dimensional nanomaterial composed of a single or few layers of carbon atoms, has been shown to create a "maze effect" within resins. This dense "maze-like" barrier significantly extends the diffusion path for water molecules and reduces permeability. However, due to its high surface energy, nanographene tends to aggregate when directly added to polyethylene resins, failing to fully exert its physical barrier properties and creating defects within the resin, which can affect its mechanical properties.

[0003] On the other hand, antimicrobial properties are also essential for packaging materials in areas such as food and medicine. Traditional polyethylene packaging materials cannot actively inhibit bacterial growth. Fresh foods (meat, fruits, and vegetables) are susceptible to contamination and spoilage from bacteria such as E. coli and mold during storage and transportation. Medical device packaging must prevent cross-contamination with pathogens such as Staphylococcus aureus to ensure the sterility of surgical instruments. Therefore, antimicrobial modification of polyethylene packaging materials has been a research hotspot in recent years. Existing antimicrobial packaging materials are often prepared by directly adding antimicrobial agents, which can lead to loss of antimicrobial components and a short antimicrobial effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a nanoparticle modified antibacterial packaging film and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a nanoparticle-modified antibacterial packaging film, wherein the nanoparticle-modified antibacterial packaging film is prepared by reacting pre-modified nanographene and 1,2-benzisothiazol-3-one to obtain modified nanographene; pre-modified polyethylene and 3-mercapto-1-propanol are reacted to obtain modified polyethylene; the modified polyethylene, functionalized aloin and modified nanographene are uniformly mixed and cast to obtain a polyethylene film; a fluorine-containing coating liquid is coated on the surface of the polyethylene film to obtain the nanoparticle-modified antibacterial packaging film; the pre-modified nanographene is prepared by reacting nanographene and 2-(2-chloroethyl)furan; the functionalized aloin is prepared by reacting aloin and 2-chloro-4,6-di(oxan-2-ylmethoxy)-1,3,5-triazine; and the pre-modified polyethylene is prepared by reacting linear low-density polyethylene and allyl dimethyl phosphate.

[0006] A method for preparing a nanoparticle-modified antibacterial packaging film, comprising the following steps: (1) Pre-modified nanographene, 1,2-benzisothiazol-3-one, and N,N-dimethylformamide were mixed uniformly in a mass ratio of 1: (8-10): (90-100), and anhydrous potassium carbonate in an equal molar amount of 1,2-benzisothiazol-3-one was added. Under nitrogen protection, the mixture was stirred at 70-75°C and 300-400 r / min for 5-6 h, centrifuged, washed with anhydrous ethanol 3-5 times, and dried at 60-65°C under vacuum conditions for 8-10 h to obtain modified nanographene. (2) Mix aloin and acetone in a mass ratio of 1: (14-16) to prepare solution A; mix 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine and acetone in a mass ratio of 1: (8-10) to prepare solution B; at 50-52°C and 300-400 r / min stirring conditions, add solution B dropwise to solution A at a molar ratio of aloin to 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine of 1:2 over 30 minutes. After the addition is complete, continue stirring and react for 10-12 hours. Dry at 50-60°C under vacuum conditions for 8-10 hours to obtain functionalized aloin; (3) Pre-modified polyethylene and m-xylene were mixed uniformly in a mass ratio of 1: (24~26), stirred at 120℃, 30~40r / min for 40~50min, 0.1~0.12 times the mass of pre-modified polyethylene 3-mercapto-1-propanol and 0.003~0.004 times the mass of pre-modified polyethylene p-toluenesulfonic acid were added, and the mixture was stirred for 3~4h. The mixture was dried at 80~90℃ under vacuum conditions for 5~6h, washed with acetone for 3~5 times, and dried at 60~70℃ under vacuum conditions for 7~8h to obtain modified polyethylene. (4) The modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene were mixed evenly, and the mixture was connected to a casting machine through a single-screw extruder for casting to obtain a polyethylene film. A fluorine-containing coating liquid was coated on the surface of the polyethylene film at a speed of 10 mm / s using a coating machine. After coating, the film was allowed to stand at room temperature for 18 to 20 hours to obtain a nanoparticle-modified antibacterial packaging film.

[0007] As an optimization, the preparation method of the pre-modified nano-graphene in step (1) is as follows: nano-graphene and N-methylpyrrolidone are uniformly mixed in a mass ratio of 1: (300~320), ultrasonically dispersed at 0~2°C for 1~2h, 2-(2-chloroethyl)furan (20~22 times the mass of nano-graphene) is added, placed in a high-pressure reactor, stirred at 96~100°C and 300~400r / min for 3~4h, centrifuged, washed with acetone 3~5 times, and dried at 60~65°C under vacuum conditions for 8~10h to obtain pre-modified nano-graphene.

[0008] As an optimization, the CAS number of the 2-(2-chloroethyl)furan is 63825-24-1; the structural formula is: .

[0009] As an optimization, the reaction mechanism of the modified nanographene in step (1) is as follows: .

[0010] As an optimization, the CAS number of 2-chloro-4,6-di(oxamethoxy)-1,3,5-triazine in step (2) is 126972-11-0; the structural formula is: .

[0011] As an optimization, the preparation method of the pre-modified polyethylene in step (3) is as follows: weigh 92-94 parts of linear low-density polyethylene, 6-8 parts of allyl dimethyl phosphate, 0.2-0.3 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 8-10 parts of acetone in parts by mass; after uniformly mixing allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone, add linear low-density polyethylene and mix uniformly, and let it stand at room temperature for 2-3 hours to obtain a mixture; place the mixture in a twin-screw extruder for extrusion and granulation, and control the mixture to stay in the twin-screw extruder for 4-6 minutes to obtain the pre-modified polyethylene.

[0012] As an optimization, the process parameters of the extrusion granulation are as follows: the temperature of each section of the twin-screw extruder is set to: 80°C in zone 1, 120°C in zone 2, 175°C in zone 3~die head, and the screw speed is 140~150r / min.

[0013] As an optimization, the model of the linear low-density polyethylene is DFDA-7042.

[0014] As an optimization, the process parameters of the tape casting in step (4) are as follows: the temperature of each zone of the single-screw extruder is set to: 160°C for zone 1, 180°C for zone 2, and 190°C for zone 3 and die head; the temperature of the tape casting machine is 180°C, and the rotation speed is 40r / min.

[0015] As an optimization, the preparation method of the fluorine-containing coating liquid in step (4) is: 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone are uniformly mixed in a mass ratio of 1: (0.03~0.05): (7~8) to prepare a fluorine-containing coating liquid.

[0016] As an optimization, the CAS number of the 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride is 64018-24-2; the structural formula is: .

[0017] As an optimization, the amounts of the modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are as follows: by mass: 90-92 parts of modified polyethylene, 8-10 parts of functionalized aloin, 3-4 parts of modified nanographene, and 1-1.4 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0018] Compared with the prior art, the present invention has the following beneficial effects: when preparing the nanoparticle-modified antibacterial packaging film, the present invention reacts nanographene and 2-(2-chloroethyl)furan to obtain pre-modified nanographene; reacts the pre-modified nanographene and 1,2-benzisothiazol-3-one to obtain modified nanographene; reacts aloin and 2-chloro-4,6-di(oxan-2-ylmethoxy)-1,3,5-triazine to obtain functionalized aloin; reacts linear low-density polyethylene and allyl dimethyl phosphate to obtain pre-modified polyethylene; reacts the pre-modified polyethylene and 3-mercapto-1-propanol to obtain modified polyethylene; uniformly mixes the modified polyethylene, functionalized aloin and modified nanographene, and performs tape casting to obtain a polyethylene film material; and coats a fluorine-containing coating liquid on the surface of the polyethylene film material to obtain the nanoparticle-modified antibacterial packaging film.

[0019] First, the furan group on 2-(2-chloroethyl)furan is reacted with nanographene to undergo DA reaction, and chlorine atoms are introduced into the nanographene to obtain pre-modified nanographene. The chlorine atoms introduced into the pre-modified nanographene are reacted with the secondary amine on 1,2-benzisothiazol-3-one to obtain modified nanographene. A benzisothiazolinone structure is introduced into the modified nanographene. The electron-deficient sulfur in the NS bond contained in the benzisothiazolinone structure can react with the sulfhydryl group in the semicystic acid of the protein active site in bacterial cells, resulting in the cleavage of the NS bond and the formation of an SS bond, thereby blocking the activity of the enzyme and causing the death of the bacteria, giving the nanoparticle-modified antibacterial packaging film excellent antibacterial properties; nanographene has a lamellar structure, which can form a physical barrier in the packaging film, extend the permeation path of water molecules, and improve the water vapor barrier performance of the packaging film. After surface modification of the nanographene, the compatibility of the nanographene with polyethylene resin can be improved.

[0020] Secondly, some hydroxyl groups on aloin are reacted with chlorine atoms on 2-chloro-4,6-di(oxan-2-ylmethoxy)-1,3,5-triazine to produce functionalized aloin, and triazine structures and epoxy groups are introduced into the functionalized aloin; the introduction of the triazine structure can improve the flame retardant properties of the packaging film, and the epoxy group can undergo a click reaction with the thiol group introduced on the modified polyethylene side chain to form a cross-linked network, thereby improving the mechanical properties of the packaging film; aloin is an anthrone compound containing a carbon glycosidic bond, has good antibacterial and antifungal effects, and is a natural antibacterial material. Adding aloin to the packaging film can further improve the antibacterial properties of the packaging film.

[0021] Finally, linear low-density polyethylene and allyl dimethyl phosphate were melt-grafted to prepare pre-modified polyethylene, and methyl phosphate groups were introduced into the side chains of the pre-modified polyethylene molecules. The hydroxyl groups on 3-mercapto-1-propanol were transesterified with methyl phosphate groups to prepare modified polyethylene, and phosphorus and thiol groups were introduced into the side chains of the modified polyethylene molecules. The introduction of phosphorus can improve the flame retardant properties of the packaging film. The introduction of thiol groups can react with the epoxy groups introduced on the functionalized aloin to form a cross-linked network, which improves the mechanical properties and also generates alcoholic hydroxyl groups. The generated alcoholic hydroxyl groups react with the acyl chloride groups on 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride to graft fluorine-containing hydrophobic long chains onto the surface of the packaging film, thereby reducing the surface free energy of the packaging film and increasing the water contact angle. It is difficult for water molecules to wet and adsorb on the surface of the packaging film, further improving the water vapor barrier ability of the packaging film. The mechanism of action is shown in the following formula: . DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] The linear low-density polyethylene used in the following examples and comparative examples is of the model DFDA-7042.

[0024] Example 1 A method for preparing a nanoparticle-modified antibacterial packaging film, comprising the following steps: (1) Nanographene and N-methylpyrrolidone were mixed in a mass ratio of 1:300, ultrasonically dispersed at 0℃ for 2h, 2-(2-chloroethyl)furan (20 times the mass of nanographene) was added, placed in a high-pressure reactor, stirred at 96℃, 300r / min for 4h, centrifuged, washed with acetone three times, and dried at 60℃ for 10h under vacuum conditions to obtain pre-modified nanographene; pre-modified nanographene, 1,2-benzisothiazol-3-one, and N,N-dimethylformamide were mixed in a mass ratio of 1:8:90, anhydrous potassium carbonate (equimolar amount of 1,2-benzisothiazol-3-one) was added, stirred at 70℃, 300r / min for 6h under nitrogen protection, centrifuged, washed with anhydrous ethanol three times, and dried at 60℃ for 10h under vacuum conditions to obtain modified nanographene; (2) Aloin and acetone were mixed at a mass ratio of 1:14 to prepare solution A; 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine and acetone were mixed at a mass ratio of 1:8 to prepare solution B; at 50°C and 300 r / min stirring conditions, solution B was uniformly added dropwise to solution A at a molar ratio of aloin to 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine of 1:2 over 30 minutes. After the addition was completed, the mixture was stirred for 12 hours and dried at 50°C for 10 hours to obtain functionalized aloin; (3) According to the mass ratio, weigh 92 parts of linear low-density polyethylene, 6 parts of allyl dimethyl phosphate, 0.2 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 8 parts of acetone; after mixing allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone, add linear low-density polyethylene and mix evenly, let it stand at room temperature for 2 hours to prepare a mixture; place the mixture in a twin-screw extruder for extrusion and granulation, and set the temperature of each section of the twin-screw extruder to: 80℃ for zone 1, 120℃ for zone 2, 175℃ for zone 3~head, and 175℃ for screw head. The rod speed is 140r / min, and the mixture is controlled to stay in the twin-screw extruder for 4 minutes to obtain pre-modified polyethylene; the pre-modified polyethylene and m-xylene are uniformly mixed in a mass ratio of 1:24, stirred at 120°C and 30r / min for 50 minutes, 0.1 times the mass of the pre-modified polyethylene 3-mercapto-1-propanol and 0.003 times the mass of the pre-modified polyethylene p-toluenesulfonic acid are added, and the stirring reaction is continued for 4 hours, and the mixture is dried at 80°C for 6 hours under vacuum conditions, washed with acetone three times, and dried at 60°C for 8 hours under vacuum conditions to obtain modified polyethylene; (4) According to the mass ratio, 90 parts of modified polyethylene, 8 parts of functionalized aloin, 3 parts of modified nanographene, and 1 part of 1,5,7-triazabicyclo[4.4.0]dec-5-ene were weighed; the modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene were mixed evenly, and the film was cast by connecting a single-screw extruder to a casting machine to obtain a polyethylene film. The temperature of each zone of the single-screw extruder was set to: The temperature of the first zone is 160℃, the second zone is 180℃, and the third zone ~ the die head is 190℃; the temperature of the casting machine is 180℃ and the speed is 40r / min; 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine and acetone are evenly mixed in a mass ratio of 1:0.03:7 to prepare a fluorine-containing coating liquid; the fluorine-containing coating liquid is coated on the surface of the polyethylene film material using a coating machine at a speed of 10mm / s, and the film is allowed to stand at room temperature for 18 hours after coating to obtain a nanoparticle-modified antibacterial packaging film.

[0025] Example 2 A method for preparing a nanoparticle-modified antibacterial packaging film, comprising the following steps: (1) Nanographene and N-methylpyrrolidone were mixed in a mass ratio of 1:310, ultrasonically dispersed at 1°C for 1.5h, 2-(2-chloroethyl)furan (21 times the mass of nanographene) was added, placed in a high-pressure reactor, stirred at 98°C, 350r / min for 3.5h, centrifuged, washed with acetone 4 times, and dried at 62.5°C under vacuum for 9h to obtain pre-modified nanographene; pre-modified nanographene, 1,2-benzisothiazol-3-one, and N,N-dimethylformamide were mixed in a mass ratio of 1:9:95, anhydrous potassium carbonate (equimolar amount of 1,2-benzisothiazol-3-one) was added, stirred at 72.5°C, 350r / min for 5.5h under nitrogen protection, centrifuged, washed with anhydrous ethanol 4 times, and dried at 62.5°C under vacuum for 9h to obtain modified nanographene; (2) Aloin and acetone were mixed at a mass ratio of 1:15 to prepare solution A; 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine and acetone were mixed at a mass ratio of 1:9 to prepare solution B; at 51°C and 350 r / min stirring conditions, solution B was uniformly added dropwise to solution A at a molar ratio of aloin to 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine of 1:2 over 30 minutes. After the addition was completed, the reaction was continued with stirring for 11 hours, and dried at 55°C under vacuum conditions for 9 hours to obtain functionalized aloin; (3) Weigh 93 parts of linear low-density polyethylene, 7 parts of allyl dimethyl phosphate, 0.25 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 9 parts of acetone by mass; mix allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone evenly, add linear low-density polyethylene and mix evenly, let it stand at room temperature for 2.5 hours to prepare a mixture; place the mixture in a twin-screw extruder for extrusion and granulation, and set the temperature of each section of the twin-screw extruder to: 80°C in zone 1, 120°C in zone 2, 175°C in zone 3~head, and screw speed The extruder was extruded at a speed of 145 r / min, and the mixture was controlled to stay in the twin-screw extruder for 5 minutes to obtain pre-modified polyethylene; the pre-modified polyethylene and m-xylene were uniformly mixed in a mass ratio of 1:25, stirred at 120°C and 35 r / min for 45 minutes, 3-mercapto-1-propanol (0.11 times the mass of the pre-modified polyethylene) and p-toluenesulfonic acid (0.0035 times the mass of the pre-modified polyethylene) were added, and the reaction was continued with stirring for 3.5 hours, and the mixture was dried at 85°C under vacuum conditions for 5.5 hours, washed with acetone 4 times, and dried at 65°C under vacuum conditions for 7.5 hours to obtain modified polyethylene; (4) Weigh 91 parts of modified polyethylene, 9 parts of functionalized aloin, 3.5 parts of modified nanographene, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene by mass; mix the modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene evenly, and connect the single-screw extruder to a casting machine for casting to obtain a polyethylene film. Set the temperature of each zone of the single-screw extruder to: The temperature of zone 1 is 160℃, zone 2 is 180℃, and zone 3~die head is 190℃; the temperature of the casting machine is 180℃ and the speed is 40r / min; 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine and acetone are mixed evenly in a mass ratio of 1:0.04:7.5 to prepare a fluorine-containing coating liquid; the fluorine-containing coating liquid is coated on the surface of the polyethylene film material using a coating machine at a speed of 10mm / s, and the film is allowed to stand at room temperature for 19 hours after coating to obtain a nanoparticle-modified antibacterial packaging film.

[0026] Example 3 A method for preparing a nanoparticle-modified antibacterial packaging film, comprising the following steps: (1) Nanographene and N-methylpyrrolidone were mixed in a mass ratio of 1:320, ultrasonically dispersed at 2°C for 1 hour, 2-(2-chloroethyl)furan (22 times the mass of nanographene) was added, placed in a high-pressure reactor, stirred at 100°C, 400 r / min for 3 hours, centrifuged, washed with acetone 5 times, and dried at 65°C under vacuum for 8 hours to obtain pre-modified nanographene; pre-modified nanographene, 1,2-benzisothiazol-3-one, and N,N-dimethylformamide were mixed in a mass ratio of 1:10:100, anhydrous potassium carbonate (equimolar amount of 1,2-benzisothiazol-3-one) was added, stirred at 75°C, 400 r / min for 5 hours under nitrogen protection, centrifuged, washed with anhydrous ethanol 5 times, and dried at 65°C under vacuum for 8 hours to obtain modified nanographene; (2) Aloin and acetone were mixed at a mass ratio of 1:16 to prepare solution A; 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine and acetone were mixed at a mass ratio of 1:10 to prepare solution B; at 52°C and 400 r / min stirring conditions, solution B was uniformly added dropwise to solution A at a molar ratio of aloin to 2-chloro-4,6-di(oxoalkyl-2-ylmethoxy)-1,3,5-triazine of 1:2 over 30 minutes. After the addition was completed, the mixture was stirred for 10 hours and dried at 60°C under vacuum conditions for 8 hours to obtain functionalized aloin; (3) According to the mass percentage, weigh 94 parts of linear low-density polyethylene, 8 parts of allyl dimethyl phosphate, 0.3 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 10 parts of acetone; after mixing allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone, add linear low-density polyethylene and mix evenly, let it stand at room temperature for 3 hours to prepare a mixture; place the mixture in a twin-screw extruder for extrusion and granulation, and set the temperature of each section of the twin-screw extruder as follows: 80℃ for zone 1, 120℃ for zone 2, 175℃ for zone 3~head, and 175℃ for screw head. The rod speed is 150r / min, and the mixture is controlled to stay in the twin-screw extruder for 6 minutes to obtain pre-modified polyethylene; the pre-modified polyethylene and m-xylene are uniformly mixed in a mass ratio of 1:26, stirred at 120°C and 40r / min for 40 minutes, 0.12 times the mass of the pre-modified polyethylene 3-mercapto-1-propanol and 0.004 times the mass of the pre-modified polyethylene p-toluenesulfonic acid are added, and the stirring reaction is continued for 3 hours. The mixture is dried at 90°C for 5 hours under vacuum conditions, washed with acetone 5 times, and dried at 70°C for 7 hours under vacuum conditions to obtain modified polyethylene; (4) According to the mass ratio, 92 parts of modified polyethylene, 10 parts of functionalized aloin, 4 parts of modified nanographene, and 1.4 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene were weighed; the modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene were mixed evenly, and the film was cast by connecting a single-screw extruder to a casting machine to obtain a polyethylene film. The temperature of each zone of the single-screw extruder was set to : Zone 1 is 160℃, Zone 2 is 180℃, Zone 3~die head is 190℃; the temperature of the casting machine is 180℃, and the speed is 40r / min; 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone are mixed evenly in a mass ratio of 1:0.05:8 to prepare a fluorine-containing coating liquid; the fluorine-containing coating liquid is coated on the surface of the polyethylene film material using a coating machine at a speed of 10mm / s, and the film is allowed to stand at room temperature for 20h after coating to obtain a nanoparticle-modified antibacterial packaging film.

[0027] Comparative Example 1: The preparation method of the nanoparticle-modified antibacterial packaging film of Comparative Example 1 differs from that of Example 2 in that step (1) is not performed, and step (4) is modified as follows: 91 parts of modified polyethylene, 9 parts of functionalized aloin, 3.5 parts of nanographene, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene are weighed by weight; the modified polyethylene, functionalized aloin, nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are uniformly mixed, and the mixture is connected to a casting machine through a single-screw extruder for casting molding. A polyethylene film was obtained, and the temperatures of each zone of a single-screw extruder were set to: 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3 (die head). The casting machine temperature was set to 180°C and the speed was set to 40 r / min. 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone were uniformly mixed in a mass ratio of 1:0.04:7.5 to prepare a fluorine-containing coating liquid. The fluorine-containing coating liquid was applied to the surface of the polyethylene film using a coating machine at a speed of 10 mm / s. The film was allowed to stand at room temperature for 19 hours after coating to produce a nanoparticle-modified antibacterial packaging film. The remaining steps were the same as in Example 2.

[0028] Comparative Example 2: The preparation method of the nanoparticle-modified antibacterial packaging film of Comparative Example 2 differs from that of Example 2 in that step (1) is not performed, and step (4) is modified as follows: 91 parts of modified polyethylene, 9 parts of functionalized aloin, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene are weighed by mass; the modified polyethylene, functionalized aloin, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are uniformly mixed, and a single-screw extruder is connected to a casting machine for casting to obtain a polyethylene film material. The temperatures of each zone of the single-screw extruder were set to 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3 (die head). The casting machine temperature was set to 180°C and the speed was set to 40 r / min. 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone were uniformly mixed in a mass ratio of 1:0.04:7.5 to prepare a fluorine-containing coating solution. The fluorine-containing coating solution was applied to the surface of the polyethylene film using a coating machine at a speed of 10 mm / s. The film was then allowed to stand at room temperature for 19 hours to produce a nanoparticle-modified antibacterial packaging film. The remaining steps were the same as in Example 2.

[0029] Comparative Example 3: The preparation method of the nanoparticle modified antibacterial packaging film of Comparative Example 3 is different from that of Example 2 in that step (2) is not performed, and step (4) is modified as follows: 91 parts of modified polyethylene, 3.5 parts of modified nanographene, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene are weighed by mass; the modified polyethylene, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are mixed uniformly, and the mixture is connected to a casting machine through a single-screw extruder to perform casting molding to obtain a polyethylene film. The temperature of each zone of the single-screw extruder was set to 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3. The casting machine temperature was set to 180°C and the rotation speed was set to 40 r / min. 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone were uniformly mixed in a mass ratio of 1:0.04:7.5 to prepare a fluorine-containing coating liquid. The fluorine-containing coating liquid was applied to the surface of the polyethylene film using a coating machine at a speed of 10 mm / s. The film was allowed to stand at room temperature for 19 hours after coating to produce a nanoparticle-modified antibacterial packaging film. The remaining steps were the same as in Example 2.

[0030] Comparative Example 4: The preparation method of the nanoparticle-modified antibacterial packaging film of Comparative Example 4 differs from that of Example 2 only in step (3). Step (3) is modified as follows: 93 parts of linear low-density polyethylene, 7 parts of allyl dimethyl phosphate, 0.25 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 9 parts of acetone are weighed by mass; allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone are mixed evenly, and then the linear low-density polyethylene is added and mixed evenly. The mixture is allowed to stand at room temperature for 2.5 hours to obtain a mixture; the mixture is placed in a twin-screw extruder for extrusion and granulation. The temperatures of each section of the twin-screw extruder are set to: 80°C in zone 1, 120°C in zone 2, and 175°C in zone 3 (die head). The screw speed is 145 r / min. The mixture is controlled to stay in the twin-screw extruder for 5 minutes to obtain modified polyethylene. The remaining steps are the same as those of Example 2.

[0031] Comparative Example 5: The preparation method of the nanoparticle modified antibacterial packaging film of Comparative Example 5 is different from that of Example 2 in that step (3) is not performed, and step (4) is modified as follows: 91 parts of linear low-density polyethylene, 9 parts of functionalized aloin, 3.5 parts of modified nanographene, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene are weighed by mass; the linear low-density polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are mixed uniformly, and a single-screw extruder is connected to a casting machine for extrusion. A polyethylene film was obtained by tape casting. The temperatures of the single-screw extruder zones were set to 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3 (die head). The casting machine temperature was set to 180°C and the speed was set to 40 r / min. 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine, and acetone were uniformly mixed in a mass ratio of 1:0.04:7.5 to prepare a fluorine-containing coating solution. The fluorine-containing coating solution was applied to the polyethylene film surface using a coating machine at a speed of 10 mm / s. The film was allowed to stand at room temperature for 19 hours after coating to produce a nanoparticle-modified antibacterial packaging film. The remaining steps were the same as in Example 2.

[0032] Comparative Example 6 The preparation method of the nanoparticle-modified antibacterial packaging film of Comparative Example 6 differs from that of Example 2 in that step (4) is different. Step (4) is modified as follows: 91 parts of modified polyethylene, 9 parts of functionalized aloin, 3.5 parts of modified nanographene, and 1.2 parts of 1,5,7-triazabicyclo[4.4.0]dec-5-ene are weighed by mass; the modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are uniformly mixed, and the mixture is connected to a casting machine through a single-screw extruder to perform casting molding to obtain a nanoparticle-modified antibacterial packaging film; the temperature of each zone of the single-screw extruder is set as follows: 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3~head; the temperature of the casting machine is 180°C, and the speed is 40r / min.

[0033] Test Example 1 Water vapor barrier performance test Test Method: Circular specimens of the Examples and Comparative Examples were cut into 74 mm diameters and tested for water vapor permeability using a water vapor transmission test system at 38°C and 90% RH in accordance with GB / T 1037-2021, "Plastic Film and Sheeting - Determination of Water Vapor Permeability - Cup Weight Gain and Loss Method." The results are shown in Table 1.

[0034]

[0035] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 1, it can be found that the nanoparticle-modified antibacterial packaging film prepared in the present invention has good water vapor barrier properties.

[0036] By comparison, the water vapor permeability of Examples 1 to 3 is lower than that of Comparative Example 2, indicating that the nanographene has a lamellar structure, which can form a physical barrier in the packaging film, extend the permeation path of water molecules, and improve the water vapor barrier performance of the packaging film. Surface modification of the nanographene can improve the compatibility of the nanographene with the polyethylene resin.

[0037] By comparison, the water vapor permeabilities of Examples 1 to 3 are lower than that of Comparative Example 6, indicating that the thiol groups introduced into the modified polyethylene side chains can undergo a click reaction with the epoxy groups introduced into the functionalized aloin to generate alcoholic hydroxyl groups. The generated alcoholic hydroxyl groups react with the acyl chloride groups on 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, grafting fluorine-containing hydrophobic long chains onto the surface of the packaging film. This reduces the surface free energy of the packaging film, increases the water contact angle, makes it difficult for water molecules to wet and adsorb on the packaging film surface, and further enhances the water vapor barrier capability of the packaging film.

[0038] Test Example 2 Mechanical properties testing Test Method: The examples and comparative examples were cut into 150 mm x 10 mm specimens. The tensile strength of the specimens was tested using a universal electronic material testing machine with a clamp spacing of 50 mm. Tensile testing was performed at a test speed of 50 mm / min. The results are shown in Table 2.

[0039]

[0040] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 2, it can be found that the nanoparticle-modified antibacterial packaging film prepared in the present invention has good mechanical properties.

[0041] By comparison, the tensile strength of Examples 1 to 3 is lower than that of Comparative Example 3, indicating that some hydroxyl groups on aloin react with the chlorine atoms on 2-chloro-4,6-di(oxamethoxy)-1,3,5-triazine to prepare functionalized aloin, and epoxy groups are introduced into the functionalized aloin; the epoxy groups can undergo a click reaction with the thiol groups introduced on the modified polyethylene side chains to form a cross-linked network, thereby improving the mechanical properties of the packaging film.

[0042] By comparison, the tensile strength of Examples 1 to 3 is less than that of Comparative Examples 4 to 5, indicating that linear low-density polyethylene and allyl dimethyl phosphate are melt-grafted to prepare pre-modified polyethylene, and methyl phosphate groups are introduced into the side chains of the pre-modified polyethylene molecules; the hydroxyl groups on 3-mercapto-1-propanol are subjected to an ester exchange reaction with the methyl phosphate groups to prepare modified polyethylene, and thiol groups are introduced into the side chains of the modified polyethylene molecules. The introduction of thiol groups can undergo a click reaction with the epoxy groups introduced on the functionalized aloin to form a cross-linked network, thereby improving the mechanical properties.

[0043] Test Example 3 Antibacterial performance testing Test method: The antibacterial activity of the examples and comparative examples was evaluated using the agar diffusion test method, and the antibacterial effect of the packaging film was determined by measuring the size of the inhibition zone on the solid culture medium. The Escherichia coli strain was added to sterile nutrient agar and activated at 37°C for 24 hours. The activated colonies were picked and placed in 0.85% normal saline, and the turbidity was adjusted to 0.50 McFarland turbidity units and the concentration was 1.5×108 CFU / mL. 0.1 mL of the bacterial suspension was mixed in 100 mL of LB culture medium and poured into a 9 cm sterile culture dish. The examples and comparative examples were cut into discs with a diameter of 6 mm, attached to the surface of the culture medium, and cultured at 37°C for 24 hours. The size of the inhibition zone (mm) was measured. The results are shown in Table 3.

[0044]

[0045] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 3, it can be found that the nanoparticle-modified antibacterial packaging film prepared in the present invention has good antibacterial properties.

[0046] By comparison, the diameters of the inhibition zones of Examples 1 to 3 are larger than those of Comparative Examples 1 to 2, indicating that the furan group on 2-(2-chloroethyl)furan undergoes a DA reaction with nanographene, introducing chlorine atoms on the nanographene to prepare pre-modified nanographene, and the chlorine atoms introduced on the pre-modified nanographene react with the secondary amine on 1,2-benzisothiazol-3-one to prepare modified nanographene, and a benzisothiazolinone structure is introduced on the modified nanographene. The electron-deficient sulfur in the NS bond contained in the benzisothiazolinone structure can react with the sulfhydryl group in the semicystic acid, an active site of the protein in the bacterial cell, to break the NS bond and form an SS bond, thereby blocking the activity of the enzyme and causing the death of the bacteria, thereby giving the nanoparticle-modified antibacterial packaging film excellent antibacterial properties.

[0047] By comparison, the diameters of the inhibition zones of Examples 1 to 3 are larger than that of Comparative Example 3, indicating that aloin is an anthrone compound containing a carbon glycosidic bond, has good antibacterial and antifungal effects, and is a natural antibacterial material. Adding aloin to the packaging film can further enhance the antibacterial properties of the packaging film.

[0048] Test Example 4 Flame retardant performance test Test method: The examples and comparative examples were prepared into standard specimens according to GB / T 2406.2-2009, and the limiting oxygen index of the standard specimens was tested. The results are shown in Table 4.

[0049]

[0050] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 4, it can be found that the nanoparticle-modified antibacterial packaging film prepared in the present invention has good flame retardant properties.

[0051] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 2, indicating that the two-dimensional sheet structure of nanographene can effectively block the transfer of heat and oxygen, forming a physical barrier and promoting carbonization. Adding nanographene to the packaging film can improve the flame retardant properties of the packaging film.

[0052] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 3, indicating that some hydroxyl groups on aloin react with the chlorine atoms on 2-chloro-4,6-di(oxamethoxy)-1,3,5-triazine to produce functionalized aloin, and a triazine structure is introduced into the functionalized aloin; the introduction of the triazine structure can improve the flame retardant properties of the packaging film.

[0053] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 5, indicating that linear low-density polyethylene and allyl dimethyl phosphate are melt-grafted to prepare pre-modified polyethylene, and phosphorus is introduced into the side chain of the pre-modified polyethylene molecule. The introduction of phosphorus can improve the flame retardant properties of the packaging film.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nanoparticle modified antibacterial packaging film, characterized in that: The nanoparticle-modified antibacterial packaging film is prepared by reacting pre-modified nanographene and 1,2-benzisothiazol-3-one to obtain modified nanographene; reacting pre-modified polyethylene and 3-mercapto-1-propanol to obtain modified polyethylene; uniformly mixing the modified polyethylene, functionalized aloin, and modified nanographene, and performing tape casting to obtain a polyethylene film; coating the surface of the polyethylene film with a fluorine-containing coating liquid to obtain the nanoparticle-modified antibacterial packaging film; the pre-modified nanographene is prepared by reacting nanographene and 2-(2-chloroethyl)furan; the functionalized aloin is prepared by reacting aloin and 2-chloro-4,6-di(oxan-2-ylmethoxy)-1,3,5-triazine; and the pre-modified polyethylene is prepared by reacting linear low-density polyethylene and allyl dimethyl phosphate.

2. A method for preparing a nanoparticle-modified antibacterial packaging film, characterized in that: The preparation method of the nanoparticle modified antibacterial packaging film comprises the following preparation steps: (1) Pre-modified nanographene, 1,2-benzisothiazol-3-one, and N,N-dimethylformamide were mixed uniformly in a mass ratio of 1: (8-10): (90-100), and anhydrous potassium carbonate in an equal molar amount of 1,2-benzisothiazol-3-one was added. The mixture was reacted at 70-75°C for 5-6 hours under nitrogen protection, and then centrifuged, washed, and dried to obtain modified nanographene. (2) Mix aloin and acetone evenly to prepare solution A; mix 2-chloro-4,6-di(oxoalkane-2-ylmethoxy)-1,3,5-triazine and acetone evenly to prepare solution B; add solution B dropwise to solution A at a constant speed within 30 minutes according to the molar ratio of aloin to 2-chloro-4,6-di(oxoalkane-2-ylmethoxy)-1,3,5-triazine of 1:

2. After the addition is completed, continue stirring and reacting for 10 to 12 hours, and vacuum dry to obtain functionalized aloin; (3) Pre-modified polyethylene and m-xylene were mixed evenly in a mass ratio of 1:(24~26), 3-mercapto-1-propanol (0.1~0.12 times the mass of pre-modified polyethylene) and p-toluenesulfonic acid (0.003~0.004 times the mass of pre-modified polyethylene) were added, and the mixture was stirred for 3~4 hours, washed with acetone, and vacuum dried to obtain modified polyethylene; (4) The modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene were mixed evenly, and the mixture was connected to a casting machine through a single-screw extruder to perform casting molding to obtain a polyethylene film. A fluorine-containing coating liquid was coated on the surface of the polyethylene film, and the film was allowed to stand at room temperature for 18 to 20 hours after coating to obtain a nanoparticle-modified antibacterial packaging film.

3. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The preparation method of the pre-modified nano-graphene in step (1) is as follows: nano-graphene and N-methylpyrrolidone are uniformly mixed in a mass ratio of 1: (300-320), ultrasonically dispersed at 0-2°C for 1-2h, 2-(2-chloroethyl)furan in an amount of 20-22 times the mass of the nano-graphene is added, placed in a high-pressure reactor, reacted at 96-100°C for 3-4h, centrifuged, washed and dried to obtain pre-modified nano-graphene.

4. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The reaction conditions of the solution A and the solution B in step (1) are: 50-52° C., 300-400 r / min.

5. The method for preparing a nanoparticle modified antibacterial packaging film according to claim 2, characterized in that: The preparation method of the pre-modified polyethylene in step (3) is as follows: weigh 92 to 94 parts of linear low-density polyethylene, 6 to 8 parts of allyl dimethyl phosphate, 0.2 to 0.3 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 8 to 10 parts of acetone in parts by mass; after uniformly mixing allyl dimethyl phosphate, dimethyl-2,5-bis(tert-butylperoxy)hexane, and acetone, add the linear low-density polyethylene and mix uniformly, and let it stand at room temperature for 2 to 3 hours to obtain a mixture; place the mixture in a twin-screw extruder for extrusion and granulation, and control the mixture to stay in the twin-screw extruder for 4 to 6 minutes to obtain the pre-modified polyethylene.

6. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 5, characterized in that: The process parameters of the extrusion granulation are as follows: the temperature of each section of the twin-screw extruder is set to: 80°C in zone 1, 120°C in zone 2, 175°C in zone 3~die head, and the screw speed is 140~150r / min.

7. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The process parameters of the tape casting in step (4) are as follows: the temperature of each zone of the single-screw extruder is set to: 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3 and die head; the temperature of the tape casting machine is 180°C, and the rotation speed is 40r / min.

8. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The coating speed of the coating machine in step (4) is 10 mm / s.

9. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The preparation method of the fluorine-containing coating liquid in step (4) is as follows: 3,3,4,4,5,5,6,6,6-nonafluorohexanoyl chloride, triethylamine and acetone are uniformly mixed in a mass ratio of 1: (0.03~0.05): (7~8) to prepare a fluorine-containing coating liquid.

10. The method for preparing a nanoparticle-modified antibacterial packaging film according to claim 2, characterized in that: The amount of modified polyethylene, functionalized aloin, modified nanographene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene used in step (4) is as follows: 90-92 parts by mass of modified polyethylene, 8-10 parts by mass of functionalized aloin, 3-4 parts by mass of modified nanographene, and 1-1.4 parts by mass of 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

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