Environment-friendly antibacterial high-barrier retort pouch and preparation method thereof

Abstract

The application discloses an environment-friendly antibacterial high-barrier retort pouch and a preparation method thereof, and belongs to the technical field of packaging materials, and is used for solving the problem that the antibacterial property and the barrier property of the retort pouch need to be further improved; the environment-friendly antibacterial high-barrier retort pouch is obtained by adhering, curing and cutting a PET film, a nylon film and a modified polypropylene film through an adhesive; the preparation method of the modified polypropylene film comprises the following steps: reacting 10-hydroxy decanaldehyde and amino-modified titanium dioxide to obtain modified titanium dioxide; reacting allyl succinic anhydride and the modified titanium dioxide to obtain allyl succinic anhydride grafted modified titanium dioxide; melt blending an intermediate I, polyethylene and a compatilizer to obtain a melt, and then extruding, casting and molding and edge cutting and winding to obtain the modified polypropylene film; the environment-friendly antibacterial high-barrier retort pouch prepared by the method has the antibacterial property and the barrier property, and also has good high-temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to an environmentally friendly antibacterial high-barrier retort pouch and its preparation method. Background Technology

[0002] Retortible packaging materials are composite plastic film bags that can be heat-treated and maintain their structure and function during high-temperature cooking. They are suitable for foods requiring high-temperature processing, including canned foods, frozen foods, and ready-to-eat foods. These packaging materials must possess good heat resistance, retort resistance, mechanical strength, and food safety to ensure they do not break, deform, or release harmful substances under high-temperature conditions. Aluminum foil is often used in combination with other materials in packaging to enhance its mechanical strength. It is used for foods requiring airtightness, high-temperature resistance, and long shelf life, such as vacuum packaging and canned goods. However, aluminum foil also has disadvantages such as being easily torn, opaque, having limited recyclability, high cost, and being prone to corrosion, and it is not environmentally friendly. Existing retortible packaging films mainly include aluminum-plastic composite films and transparent retortible composite films. Because aluminum-plastic composite films cannot be microwaved, their application range is limited. Therefore, the demand for retortible films is increasing.

[0003] Chinese patent CN113276512B discloses a recyclable retort pouch and its recyclable retort polyester film. The recyclable retort polyester film includes a heat-sealing layer and at least one polyester layer. The heat-sealing layer is formed of isophthalic acid, neopentyl glycol, polybutylene terephthalate, 1,4-cyclohexanediol, and polyethylene terephthalate-1,4-cyclohexanediol. The recyclable retort pouch is made of the recyclable retort polyester film. The recyclable retort polyester film prepared by this invention has good heat-sealing properties and high-temperature retort resistance, but does not have good antibacterial properties. Chinese patent CN102173143B discloses a retort-resistant composite film and a retort-resistant bag. The invention provides a retort-resistant composite film comprising a first CPP layer, a PVDC layer, and a second CPP layer sequentially connected by an adhesive. The resulting composite film maintains synchronized shrinkage rates across all layers during heating, stretching, and shrinkage, preventing edge curling after stretching. However, the barrier properties of the retort-resistant bag prepared by this invention need further improvement. In summary, developing a retort bag with good antibacterial properties and high barrier performance has broad market value and significant practical importance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an environmentally friendly antibacterial high-barrier retort bag and its preparation method, solving the problem that the antibacterial and barrier properties of retort bags need further improvement.

[0005] To achieve the above objectives, the present invention provides a method for preparing an environmentally friendly antibacterial high-barrier retort pouch, comprising the following steps:

[0006] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain environmentally friendly antibacterial high barrier retort pouches.

[0007] The preparation method of the modified polypropylene film includes the following steps:

[0008] Step (1) Mix nano-titanium dioxide, anhydrous ethanol and aminosilane coupling agent evenly, heat and react. After the reaction is completed, centrifuge and dry to obtain amino-modified nano-titanium dioxide.

[0009] Step (2) Add 10-hydroxydecaldehyde, amino-modified nano-titanium dioxide and potassium hydroxide to anhydrous ethanol, stir evenly, heat, react, filter, wash and dry to obtain modified nano-titanium dioxide.

[0010] Step (3) Allyl succinic anhydride and modified nano titanium dioxide are added to N,N-dimethylformamide, stirred evenly, sodium hydroxide is added, heated, reacted, the reaction is completed, filtered, washed, and dried to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0011] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO are mixed, heated and kept warm for a period of time, heated and stirred, deionized water is added and kept warm, the reaction is completed, filtered, extracted with ethyl acetate, dried, and intermediate I is obtained.

[0012] Intermediate I, polyethylene, and compatibilizer are melt-blended to obtain a melt, which is then extruded, cast, trimmed, and wound to obtain a modified polypropylene film.

[0013] Preferably, in step (1), the aminosilane coupling agent includes any one of γ-aminoethylaminopropyltrimethoxysilane and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane.

[0014] Preferably, in step (1), the mass ratio of nano-titanium dioxide, anhydrous ethanol and aminosilane coupling agent is (60-80):(2000-4000):(30-50); the reaction temperature is 65-75℃ and the reaction time is 6-8h.

[0015] Preferably, in step (2), the mass ratio of 10-hydroxydecaldehyde, amino-modified nano-titanium dioxide, potassium hydroxide and anhydrous ethanol is (200-400):(80-100):(6-10):(1000-3000); the reaction temperature is 65-75℃ and the reaction time is 1.5-3.5h.

[0016] Preferably, in step (3), the mass ratio of allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide is (180-380):(200-280):(800-1600):(10-18); the reaction temperature is 60-80℃ and the reaction time is 6-10h.

[0017] Preferably, in step (4), the mass ratio of polypropylene, allyl succinic anhydride grafted modified nano-titanium dioxide, BPO, deionized water and ethyl acetate is (200-400):(10-20):(0.2-0.4):(50-80):(600-1400).

[0018] Preferably, in step (4), the first heating temperature is 55-65℃ and the holding time is 1.5-3.5h; the second heating temperature is 85-95℃ and the stirring time is 20-40min.

[0019] Preferably, in step (4), the mass ratio of intermediate I, polyethylene and compatibilizer is (100-140):(20-40):(0.6-1).

[0020] Preferably, in step (4), the temperature of melt blending is 170-180℃.

[0021] Preferably, the compatibilizer is any one of polyoxyethylene monolaurate or polyoxyethylene lauryl ether.

[0022] Preferably, the die temperature of the extruder is 175-185℃.

[0023] Preferably, the melt blending time is 10-18 min, and the stirring speed during the blending process is 20-40 r / min.

[0024] Preferably, the melt blending is performed using a single-screw extruder.

[0025] Preferably, the temperature of the casting roll is 75-85℃, the traction speed of the casting roll is 7-8m / min, and the temperature of the cooling roll is 25℃.

[0026] Preferably, the environmentally friendly antibacterial high-barrier retort bag is prepared using the aforementioned method.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The nano-titanium dioxide in this invention is an inorganic particle with inherent antibacterial and heat-resistant properties. Appropriate addition can improve the heat resistance of the matrix. The nano-titanium dioxide used in this invention has a small size; after modification, agglomeration is effectively avoided, dispersibility is increased, and functional stability is maintained. The aminosilane coupling agent, as an organosilane, has a high silicon-oxygen bond energy, which effectively improves thermal stability and increases the heat resistance of the matrix. Nano-titanium dioxide can act as a nucleating agent; appropriate addition increases adhesion to the polypropylene matrix. Combined with the heterogeneous nucleation effect of the rigid nanoparticles, it is beneficial to increase the barrier properties of the film. The amino group in the amino-modified nano-titanium dioxide reacts chemically with the aldehyde group in 10-hydroxydecaldehyde to generate a new carbon-nitrogen double bond (-C=N-), i.e., a Schiff base. Schiff bases have inhibitory effects on various harmful bacteria and show good activity against Escherichia coli and Staphylococcus aureus. The formation of the carbon-nitrogen double bond (-C=N-) further increases the heat resistance of the matrix material. The introduced 10-hydroxydecaldehyde has a long-chain structure, which can improve the toughness of the matrix material.

[0029] 2. In this invention, the anhydride groups in the introduced allyl succinic anhydride can react with the hydroxyl groups in the modified nano-titanium dioxide to obtain allyl succinic anhydride-grafted modified nano-titanium dioxide, further improving the dispersibility of nano-titanium dioxide in the matrix material. The double bond structure contained in the allyl succinic anhydride-grafted modified nano-titanium dioxide can undergo a grafting reaction on the polypropylene chain to form covalent bonds, making the bond between the allyl succinic anhydride-grafted modified nano-titanium dioxide and polypropylene tighter and more stable. The introduction of this covalent bond not only enhances the thermal stability and mechanical properties of the modified polypropylene film, but also improves the barrier properties against water vapor and oxygen. The nitrogen and oxygen atoms in the allyl succinic anhydride-grafted modified nano-titanium dioxide can form hydrogen bonds with hydrogen atoms. The formation of hydrogen bonds reduces the free volume between polymer chains, restricts the permeation channels of small molecules, and thus improves the barrier properties.

[0030] 3. The polyethylene used in this invention is low-density polyethylene, which not only has good impact resistance, low-temperature resistance, and high-temperature resistance, but also has a certain degree of moisture resistance, and is often used in the food packaging field. Nylon film has high transparency, high tensile strength, and good heat resistance, while polypropylene has low density, high temperature resistance, and easy molding. The introduced PET film can withstand high temperatures, typically in the range of 130℃ to 180℃, and is not easily deformed or degraded during cooking. Its physical and chemical properties are relatively stable, and it can maintain its mechanical strength. The environmentally friendly antibacterial high-barrier retort pouch prepared by this invention has a three-layer structure, giving it higher oxygen barrier and water vapor barrier performance, making it a safe, effective, and highly sustainable packaging material. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation process of the environmentally friendly antibacterial high-barrier retort bag in this invention.

[0032] Figure 2 This is a flowchart illustrating the preparation process of the modified polypropylene film in this invention.

[0033] Figure 3 This is a schematic diagram of the reaction for preparing modified nano-titanium dioxide in this invention;

[0034] Figure 4 This is a schematic diagram of the reaction for preparing allyl succinic anhydride grafted modified nano-titanium dioxide in this invention. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0036] Example 1

[0037] This embodiment provides a method for preparing an environmentally friendly antibacterial high-barrier retort bag, including the following steps:

[0038] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0039] The preparation method of the modified polypropylene film includes the following steps:

[0040] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed in a mass ratio of 60:2000:30 and reacted at 65°C for 8 hours. After the reaction was completed, the mixture was centrifuged and dried at 80°C for 6 hours to obtain amino-modified nano titanium dioxide.

[0041] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 200:80:6:1000 and reacted at 65°C for 3.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 70°C for 7 h to obtain modified nano titanium dioxide.

[0042] Step (3) Allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide are mixed in a mass ratio of 180:200:800:10, stirred and reacted at 60℃ for 10h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 80℃ for 5h to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0043] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO were mixed and stirred at 100 r / min for 12 min, kept at 55℃ for 3.5 h, heated to 85℃ and stirred at 80 r / min for 40 min, deionized water was added, and kept at 85℃ for 5 h. After the reaction was completed, the mixture was filtered, extracted with ethyl acetate, and dried at 90℃ for 100 min to obtain intermediate I.

[0044] Intermediate I, polyethylene and polyoxyethylene monolaurate are melt-blended in a single screw extruder at 170°C and 20 r / min for 18 min to obtain a melt. The melt is extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and finally trimmed and wound to obtain a modified polypropylene film.

[0045] The temperature of the die head is 175℃, the temperature of the casting roll is 75℃, the traction speed of the casting roll is 7m / min, and the temperature of the cooling roll is 25℃.

[0046] The mass ratio of polypropylene, allyl succinic anhydride grafted modified nano-titanium dioxide, BPO, deionized water and ethyl acetate is 200:10:0.2:50:600.

[0047] The mass ratio of intermediate I, polyethylene, and polyoxyethylene monolaurate is 100:20:0.6.

[0048] Example 2

[0049] This embodiment provides a method for preparing an environmentally friendly antibacterial high-barrier retort bag, including the following steps:

[0050] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0051] The preparation method of the modified polypropylene film includes the following steps:

[0052] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed in a mass ratio of 65:2500:35 and reacted at 67°C for 7.5 h. After the reaction was completed, the mixture was centrifuged and dried at 85°C for 5.5 h to obtain amino-modified nano titanium dioxide.

[0053] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 250:85:7:1500 and reacted at 67°C for 3 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 75°C for 6.5 hours to obtain modified nano titanium dioxide.

[0054] Step (3) Allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide are mixed in a mass ratio of 230:220:1000:12, stirred and reacted at 65℃ for 9h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 85℃ for 4.5h to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0055] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO were mixed and stirred at 105 r / min for 11 min. The mixture was kept at 57 °C for 3 h, then heated to 87 °C and stirred at 85 r / min for 35 min. Deionized water was added and the mixture was kept at 87 °C for 4.5 h. After the reaction was completed, the mixture was filtered, extracted with ethyl acetate, and dried at 92 °C for 90 min to obtain intermediate I.

[0056] Intermediate I, polyethylene and polyoxyethylene monolaurate were melt-blended in a single screw extruder at 172°C and 25 r / min for 16 min to obtain a melt. The melt was extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and finally trimmed and wound to obtain a modified polypropylene film.

[0057] The temperature of the die head is 177℃, the temperature of the casting roll is 77℃, the traction speed of the casting roll is 7m / min, and the temperature of the cooling roll is 25℃.

[0058] The mass ratio of polypropylene, allyl succinic anhydride grafted modified nano-titanium dioxide, BPO, deionized water and ethyl acetate is 250:12:0.25:57:800.

[0059] The mass ratio of intermediate I, polyethylene, and polyoxyethylene monolaurate is 110:25:0.7.

[0060] Example 3

[0061] This embodiment provides a method for preparing an environmentally friendly antibacterial high-barrier retort bag, including the following steps:

[0062] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0063] The preparation method of the modified polypropylene film includes the following steps:

[0064] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane are mixed in a mass ratio of 70:3000:40 and reacted at 70°C for 7 hours. After the reaction is completed, the mixture is centrifuged and dried at 90°C for 5 hours to obtain amino-modified nano titanium dioxide.

[0065] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 300:90:8:2000 and reacted at 70°C for 2.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 80°C for 6 h to obtain modified nano titanium dioxide.

[0066] Step (3) Allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide are mixed in a mass ratio of 280:240:1200:14, stirred and reacted at 70℃ for 8h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 90℃ for 4h to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0067] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO were mixed and stirred at 110 r / min for 10 min, kept at 60℃ for 2.5 h, heated to 90℃ and stirred at 90 r / min for 30 min, deionized water was added, and kept at 90℃ for 4 h. After the reaction was completed, the mixture was filtered, extracted with ethyl acetate, and dried at 95℃ for 80 min to obtain intermediate I.

[0068] Intermediate I, polyethylene and polyoxyethylene monolaurate were melt-blended in a single screw extruder at 175°C and 30 r / min for 14 min to obtain a melt. The melt was extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and finally trimmed and wound to obtain a modified polypropylene film.

[0069] The temperature of the die head is 180℃, the temperature of the casting roll is 80℃, the traction speed of the casting roll is 7.5m / min, and the temperature of the cooling roll is 25℃.

[0070] The mass ratio of polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide, BPO, deionized water and ethyl acetate is 300:15:0.3:65:1000.

[0071] The mass ratio of intermediate I, polyethylene, and polyoxyethylene monolaurate is 120:30:0.8.

[0072] Example 4

[0073] This embodiment provides a method for preparing an environmentally friendly antibacterial high-barrier retort bag, including the following steps:

[0074] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0075] The preparation method of the modified polypropylene film includes the following steps:

[0076] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed in a mass ratio of 75:3500:45 and reacted at 72°C for 6.5 h. After the reaction was completed, the mixture was centrifuged and dried at 95°C for 4.5 h to obtain amino-modified nano titanium dioxide.

[0077] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 350:95:9:2500 and reacted at 72°C for 2 hours. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 85°C for 5.5 hours to obtain modified nano titanium dioxide.

[0078] Step (3) Allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide are mixed in a mass ratio of 330:260:1400:16, stirred and reacted at 75°C for 7 hours. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 95°C for 3.5 hours to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0079] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO were mixed and stirred at 115 r / min for 9 min. The mixture was kept at 62℃ for 2 h, then heated to 92℃ and stirred at 95 r / min for 25 min. Deionized water was added and the mixture was kept at 92℃ for 3.5 h. After the reaction was completed, the mixture was filtered, extracted with ethyl acetate, and dried at 97℃ for 70 min to obtain intermediate I.

[0080] Intermediate I, polyethylene and polyoxyethylene monolaurate were melt-blended in a single screw extruder at 177°C and 35 r / min for 12 min to obtain a melt. The melt was extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and finally trimmed and wound to obtain a modified polypropylene film.

[0081] The temperature of the die head is 182℃, the temperature of the casting roller is 82℃, the traction speed of the casting roller is 8m / min, and the temperature of the cooling roller is 25℃.

[0082] The mass ratio of polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide, BPO, deionized water and ethyl acetate is 350:17:0.35:72:1200.

[0083] The mass ratio of intermediate I, polyethylene, and polyoxyethylene monolaurate is 130:35:0.9.

[0084] Example 5

[0085] This embodiment provides a method for preparing an environmentally friendly antibacterial high-barrier retort bag, including the following steps:

[0086] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0087] The preparation method of the modified polypropylene film includes the following steps:

[0088] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane are mixed in a mass ratio of 80:4000:50 and reacted at 75°C for 8 hours. After the reaction is completed, the mixture is centrifuged and dried at 100°C for 4 hours to obtain amino-modified nano titanium dioxide.

[0089] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 400:100:10:3000 and reacted at 75°C for 1.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 90°C for 5 h to obtain modified nano titanium dioxide.

[0090] Step (3) Allyl succinic anhydride, modified nano titanium dioxide, N,N-dimethylformamide and sodium hydroxide are mixed in a mass ratio of 380:280:1600:18, stirred and reacted at 80℃ for 6h. After the reaction is completed, the mixture is filtered, washed with deionized water and dried at 100℃ for 3h to obtain allyl succinic anhydride grafted modified nano titanium dioxide.

[0091] Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride grafted modified nano titanium dioxide and BPO were mixed and stirred at 120 r / min for 8 min, kept at 65℃ for 1.5 h, heated to 95℃ and stirred at 100 r / min for 20 min, deionized water was added, and kept at 95℃ for 3 h. After the reaction was completed, the mixture was filtered, extracted with ethyl acetate, and dried at 100℃ for 60 min to obtain intermediate I.

[0092] Intermediate I, polyethylene and polyoxyethylene monolaurate are melt-blended in a single screw extruder at 180°C and 40 r / min for 10 min to obtain a melt. The melt is extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and finally trimmed and wound to obtain a modified polypropylene film.

[0093] The temperature of the die head is 185℃, the temperature of the casting roller is 85℃, the traction speed of the casting roller is 8m / min, and the temperature of the cooling roller is 25℃.

[0094] The mass ratio of polypropylene, allyl succinic anhydride grafted modified nano-titanium dioxide, BPO, deionized water and ethyl acetate is 400:20:0.4:80:1400.

[0095] The mass ratio of intermediate I, polyethylene, and polyoxyethylene monolaurate is 140:40:1.

[0096] Comparative Example 1

[0097] This comparative example provides a method for preparing an environmentally friendly antibacterial high-barrier retort pouch, including the following steps:

[0098] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0099] The preparation method of the modified polypropylene film includes the following steps:

[0100] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed in a mass ratio of 60:2000:30 and reacted at 65°C for 8 hours. After the reaction was completed, the mixture was centrifuged and dried at 80°C for 6 hours to obtain amino-modified nano titanium dioxide.

[0101] Step (2) 10-hydroxydecaldehyde, amino-modified nano titanium dioxide, potassium hydroxide and anhydrous ethanol are mixed in a mass ratio of 200:80:6:1000 and reacted at 65°C for 3.5 h. After the reaction is completed, the mixture is filtered, washed with deionized water, and dried at 70°C for 7 h to obtain modified nano titanium dioxide.

[0102] Step (3) Polypropylene, modified nano-titanium dioxide, polyethylene and polyoxyethylene monolaurate are melt-blended in a single screw extruder at 170°C and 20 r / min for 18 min to obtain a melt. The melt is extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and the edges are trimmed and rolled up to obtain a modified polypropylene film.

[0103] The temperature of the die head is 175℃, the temperature of the casting roller is 75℃, the traction speed of the casting roller is 7m / min, and the temperature of the cooling roller is 25℃.

[0104] The mass ratio of polypropylene, modified nano-titanium dioxide, polyethylene, and polyoxyethylene monolaurate is 95.5:4.5:20:0.6.

[0105] Comparative Example 2

[0106] This comparative example provides a method for preparing an environmentally friendly antibacterial high-barrier retort pouch, including the following steps:

[0107] PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain an environmentally friendly antibacterial high barrier retort bag with a film thickness of 80μm.

[0108] The preparation method of the modified polypropylene film includes the following steps:

[0109] Step (1) Nano titanium dioxide, anhydrous ethanol and γ-aminoethylaminopropyltrimethoxysilane were mixed in a mass ratio of 60:2000:30 and reacted at 65°C for 8 hours. After the reaction was completed, the mixture was centrifuged and dried at 80°C for 6 hours to obtain amino-modified nano titanium dioxide.

[0110] Step (2) Polypropylene, amino-modified nano-titanium dioxide, polyethylene and polyoxyethylene monolaurate are melt-blended in a single screw extruder at 170℃ and 20r / min for 18min to obtain a melt. The melt is extruded through a die and cast onto a casting roller, then cooled and shaped by a cooling roller, and the edges are trimmed and rolled up to obtain a modified polypropylene film.

[0111] The temperature of the die head is 175℃, the temperature of the casting roll is 75℃, the traction speed of the casting roll is 7m / min, and the temperature of the cooling roll is 25℃.

[0112] The mass ratio of polypropylene, amino-modified nano-titanium dioxide, polyethylene, and polyoxyethylene monolaurate is 95.5:4.5:20:0.6.

[0113] In the embodiments and comparative examples of this invention, the polyethylene is linear low-density polyethylene from Zhenhai Refining & Chemical Co., Ltd., grade: DNDA-8320; the polypropylene is purchased from Daqing Petrochemical Company of China National Petroleum Corporation, model: T30S; the PET film is from Shanghai Fuzhong Industrial Co., Ltd.; the nylon film is from Dongguang County Ruicheng Plastic Products Factory; the nano titanium dioxide is from Xuancheng Jingrui New Materials Co., Ltd., model: JR05, with an average particle size of 5nm; 10-hydroxydecaldehyde is from Jiangsu Aikon Biomedical R&D Co., Ltd., CAS number: 22136-92-1, with a purity of 95%; allyl succinic anhydride is from Shanghai Maclean Biochemical Technology Co., Ltd., CAS number: 7539-12-0; and the adhesive is two-component solvent-free retort adhesive 7735 produced by Henkel AG, Germany.

[0114] The modified polypropylene membranes prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to corresponding tests, with a membrane thickness of 50 μm in each case. The specific test results are shown below:

[0115] (1) Tensile test: The test method refers to the standard GB13022-91 "Test Method for Tensile Properties of Plastic Films", the tensile speed is 250±25mm / min, and the test results are shown in Table 1:

[0116] Table 1

[0117]

[0118] As shown in Table 1, the modified polypropylene film prepared by this invention has high tensile strength, especially Example 1, which exhibits the best tensile performance, reaching 28.5 MPa. Comparative Example 1, compared to Example 1, lacks the introduction of allyl succinic anhydride, which reduces the compatibility between the modified nano-titanium dioxide and polypropylene and polyethylene, resulting in lower dispersibility compared to Example 1. Therefore, the tensile performance of the modified polypropylene film prepared in Comparative Example 1 is lower than that of Example 1. Comparative Example 2, compared to Comparative Example 1, lacks the long-chain structure of 10-hydroxydecaldehyde, resulting in less improvement in the toughness of the matrix compared to Comparative Example 1. Therefore, the tensile performance of Comparative Example 1 is superior to that of Comparative Example 2.

[0119] (2) Barrier performance test: Water vapor transmission rate test: According to GB / T26253-2010 "Determination of water vapor transmission rate of plastic films and sheets by infrared detector", the test was conducted using a BASIC301 water vapor transmission rate tester at a temperature of 23℃ and a relative humidity of 85%; Oxygen transmission rate test: The test was conducted using a VAV1 oxygen transmission rate tester at a temperature of 23℃ and a relative humidity of 0%; The specific test results are shown in Table 2.

[0120] Table 2

[0121]

[0122] As shown in Table 2, the modified polypropylene films prepared in Examples 1-5 exhibit good barrier properties. Polyethylene itself has good water vapor barrier properties; the addition of the compatibilizer polyoxyethylene monolaurate increases compatibility with other materials, thus improving barrier performance. Nano-titanium dioxide can act as a nucleating agent; its appropriate addition increases adhesion to the polypropylene matrix, and combined with the heterogeneous nucleation effect of the rigid nanoparticles, it further enhances the barrier properties of the film. The allyl succinic anhydride-grafted modified nano-titanium dioxide obtained after modification exhibits better dispersion properties than amino-modified nano-titanium dioxide and modified nano-titanium dioxide. In Example 1, the introduction of allyl succinic anhydride-grafted modified nano-titanium dioxide into polypropylene endows the modified polypropylene membrane with excellent barrier and antibacterial properties. Without this, the barrier performance naturally decreases; therefore, the barrier performance of Comparative Example 1 is lower than that of Example 1. In Comparative Example 2, 10-hydroxydecaldehyde is missing. Its oxygen atoms can form hydrogen bonds with hydrogen atoms, which reduce the diffusion behavior of molecules within the polymer, increasing the difficulty for small molecules to pass through the membrane, thereby reducing the membrane's permeability and improving its barrier performance. Without this, the number of hydrogen bonds formed decreases, thus reducing the barrier performance; therefore, the barrier performance of Comparative Example 1 is superior to that of Comparative Example 2.

[0123] (3) Antibacterial performance test: The test method refers to standard QB / T2591-2003 "Test methods and antibacterial effects of antibacterial plastics". The test results are shown in Table 3.

[0124] Table 3

[0125]

[0126] As shown in Table 3, the modified polypropylene film prepared by this invention has a good antibacterial effect. Compared with Example 1, Comparative Example 1 has reduced antibacterial performance because allyl succinic anhydride was not added, resulting in decreased dispersibility of nano-titanium dioxide. In Comparative Example 1, the aldehyde group in 10-hydroxydecaldehyde reacts with the amino group in the amino-modified nano-titanium dioxide to form a Schiff base with antibacterial properties, further enhancing the antibacterial performance. However, without 10-hydroxydecaldehyde, a Schiff base cannot be formed, therefore the antibacterial performance of the modified polypropylene film in Comparative Example 2 is lower than that in Comparative Example 1.

[0127] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method for preparing an environmentally friendly antibacterial high-barrier retort pouch, characterized in that, Includes the following steps: PET film, nylon film and modified polypropylene film are bonded together with adhesive, cured, cut and made into bags to obtain environmentally friendly antibacterial high barrier retort pouches. The preparation method of the modified polypropylene film includes the following steps: Step (1) Mix titanium dioxide, anhydrous ethanol and aminosilane coupling agent evenly, heat and react. After the reaction is completed, centrifuge and dry to obtain amino-modified titanium dioxide. Step (2) Add 10-hydroxydecaldehyde, amino-modified titanium dioxide and potassium hydroxide to anhydrous ethanol, stir evenly, heat, react, filter, wash and dry to obtain modified titanium dioxide. Step (3) Allyl succinic anhydride and modified titanium dioxide are added to N,N-dimethylformamide, stirred evenly, sodium hydroxide is added, heated, reacted, the reaction is completed, filtered, washed, and dried to obtain allyl succinic anhydride grafted modified titanium dioxide. Step (4) Under a nitrogen atmosphere, polypropylene, allyl succinic anhydride-grafted modified titanium dioxide and Mix, heat and maintain the temperature for a period of time, heat and stir, add deionized water and maintain the temperature until the reaction is complete, filter, extract with ethyl acetate, dry, and obtain the intermediate. ; intermediate Polyethylene and compatibilizer are melt-blended to obtain a melt, which is then extruded, cast, trimmed, and wound to obtain a modified polypropylene film. In step (2), the mass ratio of 10-hydroxydecaldehyde, amino-modified titanium dioxide, potassium hydroxide and anhydrous ethanol is (200-400):(80-100):(6-10):(1000-3000); the reaction temperature is 65-75℃ and the reaction time is 1.5-3.5h.

2. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (1), the aminosilane coupling agent includes aminoethylaminopropyltrimethoxysilane, (aminoethyl)- Any one of aminopropylmethyldimethoxysilane.

3. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (1), the mass ratio of titanium dioxide, anhydrous ethanol and aminosilane coupling agent is (60-80):(2000-4000):(30-50); the reaction temperature is 65-75℃ and the reaction time is 6-8h.

4. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (3), the mass ratio of allyl succinic anhydride, modified titanium dioxide, N,N-dimethylformamide and sodium hydroxide is (180-380):(200-280):(800-1600):(10-18); the reaction temperature is 60-80℃ and the reaction time is 6-10h.

5. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (4), polypropylene, allyl succinic anhydride-grafted modified titanium dioxide, The mass ratio of deionized water to ethyl acetate is (200-400):(10-20):(0.2-0.4):(50-80):(600-1400).

6. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (4), the first heating temperature is 55-65℃ and the holding time is 1.5-3.5h; the second heating temperature is 85-95℃ and the stirring time is 20-40min.

7. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (4), the intermediate The mass ratio of polyethylene to compatibilizer is (100-140):(20-40):(0.6-1).

8. The method for preparing an environmentally friendly antibacterial high-barrier retort bag according to claim 1, characterized in that, In step (4), the temperature for melt blending is... .

9. An environmentally friendly antibacterial high-barrier retort bag prepared by the method of any one of claims 1-8.

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