A high-barrier sealed waterproof multilayer food container bag and a preparation method thereof

Abstract

The application belongs to the technical field of packing bags, and particularly relates to a high-barrier sealed waterproof multilayer food packing bag and a preparation method thereof. The multilayer food packing bag comprises an antibacterial inner layer, a barrier intermediate layer and a waterproof outer layer. The antibacterial inner layer comprises polyethylene and chitosan intercalated double-hydroxyl compound coated titanium dioxide modified aramid pulp at a mass ratio of 10-15:1. The barrier intermediate layer comprises ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer and mustard acid modified nano silicon dioxide at a mass ratio of 86-93:5-10:2-4. The waterproof outer layer comprises polypropylene. The packing bag provided by the application has excellent antibacterial, anti-puncture, barrier and waterproof functions, can be used as an inner bag of a food packing bag, and can be used for food transportation and storage to improve the shelf life of food.

Description

Technical Field

[0001] This invention belongs to the field of container bag technology, specifically relating to a high-barrier, sealed, and waterproof multilayer food container bag and its preparation method. Background Technology

[0002] FIBCs, also known as bulk packaging bags, save more space than drums or boxes, thus reducing transportation and storage costs. They are widely used in the grain, chemical powder, and cement manufacturing industries, and are increasingly entering the food and pharmaceutical sectors. The packaging form of FIBCs has evolved from a single outer bag to functional FIBCs with inner bags. The requirements for the inner bags of food-grade FIBCs are more stringent than those for conventional FIBCs. Besides possessing the good mechanical properties of conventional FIBCs to prevent damage during transportation, the materials used must also have good antibacterial properties to prevent food contamination and block oxygen and water vapor to extend the shelf life of food.

[0003] Chinese Patent CN115896974A discloses a high-strength tear-resistant woven container bag and its preparation method. The high-strength tear-resistant woven container bag includes woven yarns, which comprise the following components by weight: 10-20 parts reinforcing masterbatch, 1-5 parts polyethylene, and 75-89 parts polypropylene. The reinforcing masterbatch includes filler, which includes at least one of nano-calcium carbonate, talc, and glass micropowder. The reinforcing masterbatch also includes waste rubber powder. The filler is a filler modified with a modifier selected from stearic acid, calcium stearate, borate ester, and chlorinated paraffin. This technical solution provides a container bag suitable for carrying powdery or granular items such as food, grains, and pharmaceuticals, offering advantages such as high strength, tear resistance, and long service life. However, this technical solution focuses on the outer bag form. If only this outer bag is used, its woven structure and good air permeability may affect the shelf life of the food.

[0004] Chinese patent CN115339197A discloses a method for preparing a high-barrier, anti-expansion packaging bag, comprising the following steps: Step 1, selecting and pre-treating the materials for the inner, middle, and outer layers of the packaging bag; Step 2, fabricating the inner film layer; Step 3, fabricating the middle anti-expansion filling layer; Step 4, fabricating the outer packaging layer; Step 5, assembling and sewing the inner, middle, and outer layers together. This technical solution selects PVDC (polyvinylidene chloride) as the inner film material for the high-barrier, anti-expansion packaging bag, which possesses shrinkage, oxygen barrier, and water barrier properties, and does not decompose under microwave heating conditions. PE (polyethylene) and EVOH (ethylene-vinyl alcohol copolymer) are selected as the middle filling materials, which have good tensile properties and are suitable for packaging larger volumes. EVOH (ethylene-vinyl alcohol copolymer) has good oxygen barrier properties. Utilizing multiple polymers to make the packaging bag further enhances its barrier properties and expands its applicability. However, this technical solution uses polyvinylidene chloride as the inner membrane material, and polyvinylidene chloride is relatively expensive. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a high-barrier, sealed, and waterproof multilayer food container bag and its preparation method. By employing specific antibacterial inner layer materials, barrier middle layer materials, and waterproof outer layer materials, the container bag possesses excellent antibacterial, puncture-resistant, barrier, and waterproof functions. It can be used as the inner bag of food container bags for food transportation and storage, thereby improving the shelf life of food.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a high-barrier, sealed and waterproof multilayer food container bag, comprising an antibacterial inner layer, a barrier middle layer and a waterproof outer layer;

[0008] The antibacterial inner layer comprises polyethylene and chitosan intercalated dihydroxy compound-coated titanium dioxide modified aramid pulp in a mass ratio of 10-15:1.

[0009] The barrier interlayer comprises ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer and erucic acid modified nano-silica in a mass ratio of 86-93:5-10:2-4.

[0010] The waterproof outer layer comprises polypropylene.

[0011] In some preferred embodiments, the polyethylene comprises low-density polyethylene and linear low-density polyethylene in a mass ratio of 1:3-5.

[0012] Preferably, the melt flow rate of the low-density polyethylene is 3-5 g / 10 min (190℃ / 2.16 kg), more preferably 4 g / 10 min (190℃ / 2.16 kg), and the grade is Anteo. TM FK1820.

[0013] Preferably, the melt flow rate of the linear low-density polyethylene is 1-2 g / 10 min (190℃ / 2.16 kg), more preferably 1.5 g / 10 min (190℃ / 2.16 kg), and the grade is Sinopec Maoming 2426K.

[0014] In some preferred embodiments, the titanium dioxide modified aramid pulp is prepared by mixing tetrabutyl titanate and an ethanol dispersion of aramid pulp evenly, heating and reacting, and washing and drying after the reaction is completed.

[0015] Preferably, the aramid pulp has a fiber length of 0.65-1.05 mm and is purchased from Yantai Taihexing Materials Technology Co., Ltd., model number: 1628.

[0016] Preferably, the mass ratio of tetrabutyl titanate to aramid pulp is 1:2-3, and more preferably 1:2.5.

[0017] Preferably, the ethanol dispersion of the aramid pulp has a mass concentration of 10-30%, more preferably 20%.

[0018] More preferably, the preparation method of the titanium dioxide modified aramid pulp is as follows: the ethanol dispersion of tetrabutyl titanate and aramid pulp is mixed evenly, and heated at 60-80℃ for 2-4 hours. After the reaction is completed, the pulp is washed and dried to obtain the final product.

[0019] In some preferred embodiments, the preparation method of the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound is as follows: magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water are mixed evenly, heated to react, filtered and dried to obtain titanium dioxide modified aramid pulp coated with dihydroxy compound; it is then added to a chitosan solution, heated and stirred, filtered and dried to obtain the final product.

[0020] This invention creatively prepares titanium dioxide-modified aramid pulp coated with chitosan-intercalated dihydroxy compounds. First, titanium dioxide is used to modify the aramid pulp. Then, dihydroxy compounds are used to coat the titanium dioxide-modified aramid pulp. Finally, chitosan is intercalated between the layers of the dihydroxy compounds. It was found that compared to titanium dioxide-modified aramid pulp alone, chitosan-intercalated dihydroxy compounds achieve a synergistic improvement in the antibacterial properties, puncture resistance, and barrier properties of bulk bags. It is speculated that this is because the titanium dioxide on the surface of the aramid pulp not only exerts its own antibacterial properties, but also… Furthermore, it disperses on the surface of aramid pulp, forming a micro-nano rough structure, which is conducive to being coated by dihydroxy compounds. The coating of titanium dioxide-modified aramid pulp by dihydroxy compounds avoids the aggregation of titanium dioxide, prolongs its activity, and its parallel structure of sheets can prevent gas penetration. At the same time, chitosan intercalation between the dihydroxy compound layers not only realizes the slow release of chitosan and improves antibacterial properties, but also fills the spaces between the dihydroxy compound layers with chitosan, further improving the densification structure, enhancing barrier properties and interfacial strength, and reducing stress concentration.

[0021] In addition, the inventors also discovered that when aramid pulp is replaced with glass fiber, the puncture resistance and barrier properties of the FIBC (Flexible Intermediate Bulk Container) decrease. This is presumably because the aramid pulp molecular chain contains rigid benzene rings and flexible ether bonds, forming a unique tough-rigid balance structure that can absorb impact energy through molecular chain slippage. Glass fiber, on the other hand, lacks the extension of its molecular chains, thus leading to a decrease in the puncture resistance of the FIBC. Simultaneously, the aramid pulp surface contains polar groups, which easily form a composite structure with titanium dioxide, enhancing interfacial bonding; while the glass fiber surface has a siloxane structure, resulting in weak bonding with titanium dioxide and reduced barrier properties.

[0022] When dihydroxy compounds were replaced with montmorillonite, the puncture resistance and barrier properties of the FIBCs also decreased. It is speculated that this is because the dihydroxy compounds have a better binding effect with titanium dioxide-modified aramid pulp and chitosan, thereby enhancing the overall performance of the FIBCs.

[0023] Preferably, the mass ratio of magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water is 0.5-0.8:0.2-0.4:0.3-0.5:0.2-0.4:20-30, and more preferably 0.6:0.3:0.4:0.3:25.

[0024] Preferably, the mass ratio of chitosan to titanium dioxide-modified aramid pulp coated with dihydroxy compounds is 1:4-6, more preferably 1:5.

[0025] Preferably, the chitosan solution is prepared by mixing chitosan and water in a mass ratio of 2-5:95-98, and adjusting the pH to 4-6 using a 2% acetic acid solution.

[0026] More preferably, the preparation method of the chitosan-intercalated dihydroxy compound-coated titanium dioxide modified aramid pulp is as follows: magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water are mixed evenly, heated and reacted at 120-130℃ for 6-8h, filtered and dried to obtain dihydroxy compound-coated titanium dioxide modified aramid pulp; added to chitosan solution, heated and stirred at 60-70℃ for 3-6h, filtered and dried to obtain the final product.

[0027] In some preferred embodiments, the ethylene content of the ethylene-vinyl alcohol copolymer is 40-50 wt%.

[0028] Preferably, the ethylene-vinyl alcohol copolymer has an ethylene content of 48 wt% and is graded EVOH H4815Soarnol.

[0029] In some preferred embodiments, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 10-16 wt%.

[0030] Preferably, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 14 wt%, and the brand name is ExxonMobil. TM EVA 02514FL.

[0031] In some preferred embodiments, the erucic acid modified nano-silica is prepared by mixing nano-silica, erucic acid and ethanol evenly, heating and stirring, filtering and drying to obtain the final product.

[0032] While ethylene-vinyl alcohol copolymers possess good barrier properties, their barrier performance is poor under high humidity conditions. To address this issue, the inventors unexpectedly discovered during experiments that the addition of erucic acid-modified nano-silica significantly improves the barrier performance of FIBCs under high humidity conditions compared to erucic acid-modified nanocellulose. This is speculated to be due to two main reasons: firstly, the long-chain alkyl groups of erucic acid are chemically bonded to the silica surface, forming a dense hydrophobic layer that effectively blocks water molecule penetration; while nanofibers, even after erucic acid modification, retain some hygroscopicity in their natural hydrophilic skeleton, making them susceptible to water molecule penetration; secondly, the spherical, dense barrier properties of silica complement the layered barrier properties of the dihydroxy compounds in the antibacterial inner layer, thus ensuring excellent barrier performance of the FIBC under high humidity conditions.

[0033] Preferably, the preparation method of the erucic acid modified nano silica is as follows: nano silica, erucic acid and ethanol are mixed evenly, heated and stirred at 80-90℃ for 30-60 min, filtered and dried to obtain the product.

[0034] Preferably, the particle size of the nano-silica is 10-30 nm, and more preferably 20 nm.

[0035] Preferably, the mass ratio of the nano-silica, erucic acid and ethanol is 6-10:0.1-0.2:25-35, and more preferably 8:0.15:30.

[0036] In some preferred embodiments, the polypropylene comprises homopolymer polypropylene and random copolymer polypropylene in a mass ratio of 4-6:1.

[0037] Preferably, the melt flow rate of the homopolymer polypropylene is 2-4 g / 10 min (230℃ / 2.16 kg).

[0038] Preferably, the homopolymer polypropylene has a melt flow rate of 3.2 g / 10 min (230℃ / 2.16 kg) and a grade of PPH-F03G.

[0039] Preferably, the melt flow rate of the random copolymer polypropylene is 4-8 g / 10 min.

[0040] (230℃ / 2.16kg).

[0041] Preferably, the melt flow rate of the random copolymer polypropylene is 6 g / 10 min.

[0042] (230℃ / 2.16kg), Brand: Moplen RP210M.

[0043] In some preferred embodiments, the thickness percentages of the antibacterial inner layer, the barrier intermediate layer, and the waterproof outer layer are 20-30%: 45-65%: 15-25%, preferably 25%: 55%: 20%.

[0044] Preferably, the thickness of the high-barrier, waterproof, multi-layer food container bag is 80-100 μm.

[0045] The second aspect of the present invention provides a method for preparing the above-mentioned high-barrier, sealed and waterproof multilayer food container bag, comprising the following steps: placing the raw materials for the antibacterial inner layer, the raw materials for the barrier middle layer and the raw materials for the waterproof outer layer into a three-layer co-extrusion blown film machine, and then performing melt extrusion blown film to obtain the product.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. This invention creatively prepares titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compounds, which achieves a synergistic improvement in the antibacterial properties, puncture resistance and barrier properties of container bags compared to single titanium dioxide modified aramid pulp and chitosan intercalated dihydroxy compounds.

[0048] 2. The present invention uses aramid pulp to improve the puncture resistance and barrier properties of the container bag.

[0049] 3. The present invention uses dihydroxy compounds to improve the puncture resistance and barrier properties of the container bag.

[0050] 4. This invention uses erucic acid-modified nano-silica to improve the barrier performance of container bags under high humidity conditions. Detailed Implementation

[0051] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0052] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0053] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available or prepared by conventional methods in the art.

[0054] Example 1

[0055] A high-barrier, sealed, and waterproof multilayer food container bag, consisting of an antibacterial inner layer, a barrier middle layer, and a waterproof outer layer;

[0056] The antibacterial inner layer is composed of titanium dioxide modified aramid pulp coated with polyethylene and chitosan intercalated dihydroxy compound in a mass ratio of 10:1.

[0057] The barrier interlayer is composed of ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer and erucic acid modified nano-silica in a mass ratio of 86:10:4.

[0058] The waterproof outer layer is made of polypropylene.

[0059] The polyethylene is composed of low-density polyethylene and linear low-density polyethylene in a mass ratio of 1:3.

[0060] The low-density polyethylene has a melt flow rate of 4 g / 10 min (190℃ / 2.16 kg) and is graded Anteo. TM FK1820.

[0061] The linear low-density polyethylene has a melt flow rate of 1.5 g / 10 min (190℃ / 2.16 kg) and is graded Sinopec Maoming 2426K.

[0062] The preparation method of the titanium dioxide modified aramid pulp is as follows: Tetrabutyl titanate and aramid pulp ethanol dispersion are mixed evenly, heated at 70°C for 3 hours, and washed and dried after the reaction is completed.

[0063] The mass ratio of tetrabutyl titanate (CAS No.: 5593-70-4) to aramid pulp is 1:2.5.

[0064] The aramid pulp has a fiber length of 0.65-1.05 mm and was purchased from Yantai Taihexing Materials Technology Co., Ltd., model number: 1628.

[0065] The ethanol dispersion of the aramid pulp has a mass concentration of 20%.

[0066] The preparation method of the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound is as follows: magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water are mixed evenly, heated and reacted at 120°C for 7 hours, filtered and dried to obtain titanium dioxide modified aramid pulp coated with dihydroxy compound; added to chitosan solution, heated and stirred at 60°C for 5 hours, filtered and dried to obtain the final product.

[0067] The mass ratio of magnesium nitrate (CAS No.: 13446-18-9), aluminum nitrate (CAS No.: 7784-27-2), urea (CAS No.: 57-13-6), titanium dioxide modified aramid pulp, and water is 0.6:0.3:0.4:0.3:25.

[0068] The mass ratio of chitosan and dihydroxy compound-coated titanium dioxide modified aramid pulp is 1:5.

[0069] The chitosan solution is prepared by mixing chitosan (CAS No.: 9012-76-4) and water in a mass ratio of 3:97, and adjusting the pH to 5 with a 2% acetic acid solution.

[0070] The ethylene-vinyl alcohol copolymer has an ethylene content of 48 wt% and is graded EVOH H4815 Soarnol.

[0071] The ethylene-vinyl acetate copolymer has a vinyl acetate content of 14 wt%, and the brand name is ExxonMobil. TM EVA 02514FL.

[0072] The preparation method of the erucic acid modified nano silica is as follows: mix nano silica, erucic acid and ethanol evenly, heat and stir at 80°C for 40 min, filter and dry to obtain the product.

[0073] The mass ratio of the nano-silica, erucic acid (CAS No.: 112-86-7), and ethanol is 8:0.15:30.

[0074] The nano-silica has a particle size of 20nm and was purchased from Xi'an Bona Materials Technology Co., Ltd., model number: BN-SiO2-01.

[0075] The polypropylene comprises homopolymer polypropylene and random copolymer polypropylene in a mass ratio of 5:1.

[0076] The homopolymer polypropylene has a melt flow rate of 3.2 g / 10 min (230℃ / 2.16 kg) and a grade of PPH-F03G.

[0077] The random copolymer polypropylene has a melt flow rate of 6 g / 10 min (230℃ / 2.16 kg) and is graded MoplenRP210M.

[0078] The thickness percentages of the antibacterial inner layer, the barrier intermediate layer, and the waterproof outer layer are 25%:55%:20%.

[0079] The thickness of the high-barrier, waterproof, multi-layer food container bag is 100μm.

[0080] The preparation method of the above-mentioned high-barrier, sealed and waterproof multilayer food container bag is as follows: the raw materials of the antibacterial inner layer, the raw materials of the barrier middle layer and the raw materials of the waterproof outer layer are placed in a three-layer co-extrusion blown film machine, and the film is obtained by melt extrusion blown film.

[0081] Example 2

[0082] A high-barrier, sealed, and waterproof multilayer food container bag differs from Example 1 only in that the antibacterial inner layer is composed of titanium dioxide-modified aramid pulp coated with polyethylene and chitosan intercalated dihydroxy compounds in a mass ratio of 15:1; the barrier middle layer is composed of ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, and erucic acid-modified nano-silica in a mass ratio of 93:5:2; all other aspects are the same.

[0083] The preparation method of the above-mentioned high-barrier, sealed, and waterproof multilayer food container bag is the same as that in Example 1.

[0084] Example 3

[0085] A high-barrier, sealed, and waterproof multilayer food container bag, differing from Example 1 only in that the antibacterial inner layer is composed of titanium dioxide-modified aramid pulp coated with polyethylene and chitosan intercalated dihydroxy compound in a mass ratio of 12:1.

[0086] The barrier intermediate layer is composed of ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer and erucic acid modified nano-silica in a mass ratio of 90:7:3; all other components are the same.

[0087] The preparation method of the above-mentioned high-barrier, sealed, and waterproof multilayer food container bag is the same as that in Example 1.

[0088] Comparative Example 1

[0089] The difference from Example 3 is that the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound was replaced with an equal mass of titanium dioxide modified aramid pulp; all other aspects are the same.

[0090] Comparative Example 2

[0091] The difference from Example 3 is that the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound is replaced with an equal mass of chitosan intercalated dihydroxy compound; all other aspects are the same.

[0092] Comparative Example 3

[0093] The difference from Example 3 is that the aramid pulp was replaced with an equal mass of glass fiber with a fiber diameter of 14 μm, purchased from Qingdao Jiachuang New Materials Co., Ltd., item number: 415A; all other aspects are the same.

[0094] Comparative Example 4

[0095] The difference from Example 3 is that the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound was replaced with an equal mass of titanium dioxide modified aramid pulp coated with chitosan intercalated montmorillonite.

[0096] The preparation method of the chitosan-intercalated montmorillonite-coated titanium dioxide-modified aramid pulp is as follows: montmorillonite and titanium dioxide-modified aramid pulp are added to a chitosan solution, heated and stirred at 60°C for 5 hours, filtered, and dried to obtain the pulp; the mass ratio of chitosan, montmorillonite, and titanium dioxide-modified aramid pulp is 1:1.

[0097] 3.5:1.5; Montmorillonite was purchased from Guangzhou Yifeng Chemical Technology Co., Ltd., model: TY-710C; all other components are the same.

[0098] Comparative Example 5

[0099] The difference from Example 3 is that the erucic acid-modified nano-silica is replaced with an equal mass of nano-silica, otherwise they are the same.

[0100] Comparative Example 6

[0101] The difference from Example 3 is that nano-silica was replaced with an equal mass of nano-cellulose, which was purchased from Zhejiang Jinjiahao Green Nanomaterials Co., Ltd., model CNF-B5; all other aspects are the same.

[0102] Performance testing:

[0103] 1. Oxygen permeability: Tested according to standard GB / T 1038-2022;

[0104] 2. Water vapor transmission rate: Tested according to standard GB / T 1037-2021;

[0105] 3. Antibacterial rate: Tested according to standard GB / T 31402-2015;

[0106] 4. Puncture resistance: Tested according to standard GB / T 37841-2019;

[0107] The results are shown in Table 1:

[0108] Table 1. Performance test results of high-barrier, waterproof, and sealing multilayer food container bags in Examples 1-3 and Comparative Examples 1-6

[0109]

[0110] As shown in Table 1, in Comparative Example 1, the titanium dioxide-modified aramid pulp coated with chitosan intercalated dihydroxy compound was replaced with an equal mass of titanium dioxide-modified aramid pulp; in Comparative Example 2, the titanium dioxide-modified aramid pulp coated with chitosan intercalated dihydroxy compound was replaced with an equal mass of chitosan intercalated dihydroxy compound. The resulting FIBCs exhibited poorer barrier properties, puncture resistance, and antibacterial properties. Furthermore, in terms of puncture resistance, the combined puncture resistance of Comparative Example 1 and Comparative Example 2 was still inferior to that of Examples 1-3. This indicates that the synergistic effect of titanium dioxide-modified aramid pulp and chitosan intercalated dihydroxy compound improved the puncture resistance of the FIBCs.

[0111] In Comparative Example 3, aramid pulp was replaced with an equal mass of glass fiber; in Comparative Example 4, chitosan-intercalated dihydroxy compound-coated titanium dioxide-modified aramid pulp was replaced with an equal mass of chitosan-intercalated montmorillonite-coated titanium dioxide-modified aramid pulp; the resulting container bags exhibited poorer barrier properties and puncture resistance.

[0112] Comparative Example 5 replaced erucic acid-modified nano-silica with an equal mass of nano-silica; Comparative Example 6 replaced nano-silica with an equal mass of nano-cellulose; the resulting bulk bags showed a significant decrease in barrier performance, especially under high humidity conditions.

[0113] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A high-barrier, sealed, and waterproof multi-layer food container bag, characterized in that, It includes an antibacterial inner layer, a barrier middle layer, and a waterproof outer layer; The antibacterial inner layer comprises polyethylene and chitosan intercalated dihydroxy compound-coated titanium dioxide modified aramid pulp in a mass ratio of 10-15:

1. The barrier interlayer comprises ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer and erucic acid modified nano-silica in a mass ratio of 86-93:5-10:2-4. The waterproof outer layer comprises polypropylene; The preparation method of the titanium dioxide modified aramid pulp coated with chitosan intercalated dihydroxy compound is as follows: magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water are mixed evenly, heated to react, filtered and dried to obtain titanium dioxide modified aramid pulp coated with dihydroxy compound; it is added to chitosan solution, heated and stirred, filtered and dried to obtain the final product. The preparation method of the titanium dioxide modified aramid pulp is as follows: Tetrabutyl titanate and aramid pulp ethanol dispersion are mixed evenly, heated to react, and washed and dried after the reaction is completed.

2. The high-barrier, waterproof, multi-layer food container bag according to claim 1, characterized in that, The polyethylene includes low-density polyethylene and linear low-density polyethylene in a mass ratio of 1:3-5; the melt flow rate of the low-density polyethylene is 3-5 g / 10 min; and the melt flow rate of the linear low-density polyethylene is 1-2 g / 10 min.

3. The high-barrier, waterproof, multi-layer food container bag according to claim 2, characterized in that, The mass ratio of magnesium nitrate, aluminum nitrate, urea, titanium dioxide modified aramid pulp and water is 0.5-0.8:0.2-0.4:0.3-0.5:0.2-0.4:20-30.

4. The high-barrier, waterproof, multi-layer food container bag according to any one of claims 1-3, characterized in that, The ethylene-vinyl alcohol copolymer has an ethylene content of 40-50 wt%; the ethylene-vinyl acetate copolymer has a vinyl acetate content of 10-16 wt%.

5. The high-barrier, waterproof, multi-layer food container bag according to claim 4, characterized in that, The preparation method of the erucic acid modified nano silica is as follows: mix nano silica, erucic acid and ethanol evenly, heat and stir, filter and dry to obtain the product.

6. The high-barrier, waterproof, multi-layer food container bag according to claim 5, characterized in that, The mass ratio of the nano-silica, erucic acid and ethanol is 6-10:0.1-0.2:25-35.

7. The high-barrier, waterproof, multi-layer food container bag according to claim 6, characterized in that, The polypropylene comprises homopolymer polypropylene and random copolymer polypropylene in a mass ratio of 10-15:1; the melt flow rate of the homopolymer polypropylene is 2-4 g / 10 min; and the melt flow rate of the random copolymer polypropylene is 4-8 g / 10 min.

8. The high-barrier, waterproof, multi-layer food container bag according to any one of claims 5-7, characterized in that, The thickness percentages of the antibacterial inner layer, the barrier middle layer, and the waterproof outer layer are 20-30%: 45-65%: 15-25%.

9. The method for preparing the high-barrier, waterproof, multi-layer food container bag according to any one of claims 1-8, characterized in that, Includes the following steps: The raw materials for the antibacterial inner layer, the barrier middle layer, and the waterproof outer layer are placed in a three-layer co-extrusion blown film machine and then melt-extruded and blown into film to obtain the final product.

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