High-barrier tensile composite material and packaging bag

Abstract

The invention relates to a high-barrier tensile composite material and a packaging bag, and belongs to the technical field of packaging bags. The composite material adopts a'polyamide / modified ethylene-vinyl alcohol copolymer / polyethylene 'three-layer co-extrusion structure, and the core of the composite material is that a multifunctional modifier prepared by chemical synthesis is uniformly dispersed in a modified ethylene-vinyl alcohol copolymer layer; molecules of the modifier integrate an o-hydroxybenzophenone ultraviolet absorption structure and a pyridyl long-chain quaternary ammonium salt antibacterial structure, and the o-hydroxybenzophenone ultraviolet absorption structure and the pyridyl long-chain quaternary ammonium salt antibacterial structure act together, so that the broad-spectrum ultraviolet protection is realized, and meanwhile, the antibacterial property is provided; a silane coupling agent structure and a long-chain alkyl group at the tail end can respectively form strong polar combination with a polyamide layer in the processing process and generate physical entanglement with a polyethylene layer, and the overall hydrophobicity and the interface bonding strength are remarkably improved. The composite material has the advantages of high barrier property, antibacterial property, ultraviolet aging resistance, high tensile strength and excellent interlayer binding force, and is especially suitable for the field of high-end packaging with strict requirements on fresh-keeping and durability.

Description

Technical Field

[0001] This invention belongs to the field of packaging bag technology, specifically, it relates to a high-barrier tensile composite material and a packaging bag. Background Technology

[0002] Ethylene-vinyl alcohol copolymer (EVOH) has become a key material in the high-end packaging field due to its excellent gas barrier properties, high transparency, and good processing performance. Especially in multilayer composite packaging structures represented by polyethylene (PE) / EVOH / polyamide (PA), EVOH is an indispensable high-barrier core layer. However, EVOH itself does not possess antibacterial properties, failing to meet the growing demand for antibacterial packaging in fields such as fresh food and medical devices. Furthermore, in the PE / EVOH / PA multilayer structure, there is a significant polarity difference between EVOH and the outer PA layer and the heat-sealing inner PE layer, resulting in extremely poor interfacial compatibility. This leads to weak interlayer adhesion and delamination during composite film preparation, severely affecting the overall strength, barrier integrity, and safety of the packaging bag. In addition, traditional packaging materials generally have insufficient resistance to ultraviolet aging, not only affecting the lifespan of the packaging bag itself but also failing to effectively block ultraviolet rays. Transmitted ultraviolet rays directly cause spoilage and loss of the contents of food, medicine, etc., within the packaging.

[0003] To overcome the aforementioned shortcomings, existing technologies typically employ physical blending to add small-molecule antibacterial agents and ultraviolet absorbers to EVOH resins, or use general-purpose compatibilizers between layers. However, this method has significant drawbacks: small-molecule additives are prone to migration and precipitation, leading not only to poor functional durability but also potentially causing food safety issues.

[0004] Therefore, developing a chemical modification technology that can form a strong bond with the EVOH matrix, integrate multiple functions, and fundamentally improve its compatibility with PE and PA layers has become the key to the current preparation of high-barrier and tensile packaging materials. Summary of the Invention

[0005] The purpose of this invention is to provide a title and its preparation method to solve the problems mentioned in the background art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0008] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0009] A packaging bag is made of a high-barrier, tensile-resistant composite material. The specific preparation steps are as follows:

[0010] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, and polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of a co-extrusion blown film machine and extruded at 200-230℃ through the composite die head to obtain a high-barrier tensile composite material. Then, the high-barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0011] Furthermore, the mass ratio of the modified barrier layer masterbatch, the polyethylene heat-sealing layer masterbatch, and the polyamide substrate layer masterbatch is 50-60:25-30:25-30.

[0012] Furthermore, the preparation method of the modified barrier layer masterbatch is as follows:

[0013] S1. Under ice-water bath conditions, pyridine-4-formyl chloride, p-hydroxystyrene, and pyridine are mixed in a reaction vessel, stirred evenly, and then the ice-water bath is removed and the reaction is carried out at room temperature for 2-6 hours. After the reaction is completed, the reaction solution is poured into ice water, filtered, and the filtrate is discarded to obtain a solid. The obtained solid is then washed with deionized water and dried to obtain pyridinephenol ester.

[0014] S2. Pyridine phenol ester, aluminum chloride, and dichlorobenzene are mixed in a reaction vessel and stirred evenly. The mixture is then reacted at 100-130℃ for 4-6 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. The reaction solution is then concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane and the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0015] S3. Mix the ultraviolet absorber, long-chain halogenated hydrocarbon, and N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 45-65℃ for 8-12 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter and discard the filtrate to obtain a solid. Finally, dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0016] S4. Mix the UV antibacterial agent, aminosilane, and toluene in a reaction vessel, stir until homogeneous, and react at 60-80℃ for 4-6 hours. After the reaction is complete, cool to room temperature and then remove the solvent by rotary evaporation to obtain the modifier.

[0017] S5. Mix the modifier and ethylene-vinyl alcohol copolymer evenly, then put the mixture into a twin-screw extruder for melt extrusion, cool and granulate to obtain the modified barrier layer masterbatch.

[0018] Furthermore, the mass ratio of pyridine-4-formyl chloride to p-hydroxystyrene in S1 is 1.7-4.5:1.8-4.6.

[0019] Furthermore, the mass ratio of pyridine ester to aluminum chloride in S2 is 2.3-5.9:2.6-6.8.

[0020] Furthermore, the mass ratio of ultraviolet absorber to long-chain halogenated hydrocarbons in S3 is 1.8-4.7:2.0-5.2.

[0021] Furthermore, the long-chain halogenated hydrocarbon in S3 is at least one of 1-chlorododecane, 1-chlorotridecane, and 1-chlorotetradecane.

[0022] Furthermore, the mass ratio of ultraviolet antibacterial agent to aminosilane in S4 is 2.6-7.1:1.5-3.7.

[0023] Furthermore, the aminosilane in S4 is at least one of 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane.

[0024] Furthermore, the mass ratio of modifier to ethylene-vinyl alcohol copolymer in S5 is 3-8:70-80.

[0025] The beneficial effects of this invention are:

[0026] 1) In this invention, pyridine-4-formyl chloride and p-hydroxystyrene are esterified to form a phenolic ester, which is then rearranged by Friedel to obtain an o-hydroxyphenylpropanedione structure containing pyridine and having ultraviolet absorption function. Then, a pyridine-based long-chain quaternary ammonium salt structure is synthesized by combining pyridine with a long-chain alkyl group to give the modifier an antibacterial effect. Finally, a silane coupling agent structure is introduced to obtain the final multifunctional modifier. The modifier is used to modify EVOH and then compounded with PA and PE to obtain a high-barrier tensile composite material and packaging bag.

[0027] 2) The modifier prepared by this invention has an o-hydroxybenzophenone structure, which can form reversible intramolecular hydrogen bonds to absorb the energy of ultraviolet light and convert it into heat energy when exposed to ultraviolet light. In addition, the modifier of this invention also has a pyridyl long-chain quaternary ammonium salt structure. The pyridyl long-chain quaternary ammonium salt not only has good antibacterial properties, but the quaternary ammonium salt structure can also be incorporated into the conjugated system of o-hydroxybenzophenone, significantly enhancing the intramolecular electron donation and electron withdrawal effect, reducing the band gap, enabling the molecule to absorb ultraviolet light with longer wavelengths, achieving a red shift in the absorption spectrum, and fully covering the entire ultraviolet spectrum range. Using the modifier of this invention to modify EVOH and compound it with PE and PA to prepare packaging bags effectively improves the overall antibacterial properties and UV aging resistance of the packaging bags.

[0028] 3) The modifier obtained by this invention has a silane coupling agent structure. During the melt processing into packaging bags, the ethoxy group on the silane hydrolyzes to generate silanol, which condenses with the abundant hydroxyl groups on the EVOH molecular chain to form a strong Si-OC covalent bond, thereby uniformly fixing the modifier in the EVOH polymer network. At the same time, a strong cation-dipole interaction is generated between the cation of the quaternary ammonium salt and the dipole moment of the carbonyl group in the amide bond, resulting in a strong bond between them. Meanwhile, the long-chain alkyl group at the end of the molecule diffuses deeply with the polyethylene molecular chain and entangles with it through the principle of like dissolves like, forming a strong physical interlocking network. This fundamentally solves the problem of interfacial incompatibility and easy delamination caused by the difference in material polarity in multilayer composite films. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0031] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0032] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0033] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0034] The room temperature was 25±5℃.

[0035] Example 1

[0036] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0037] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0038] A packaging bag is made of a high-barrier, tensile-resistant composite material, and the specific preparation method is as follows:

[0039] Step 1: According to the mass fraction, 1.7 parts of pyridine-4-formyl chloride, 1.8 parts of p-hydroxystyrene, and 15 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed and the mixture was reacted at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into ice water, filtered to obtain a solid, and then the obtained solid was washed with deionized water and dried to obtain pyridinephenol ester.

[0040] Step 2: According to the mass fraction, 2.3 parts of pyridine phenol ester, 2.6 parts of aluminum chloride, and 50 parts of dichlorobenzene are mixed in a reaction vessel, stirred evenly, and reacted at 130℃ for 4 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. Then, the reaction solution is concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0041] Step 3: According to the mass fraction, mix 1.8 parts of ultraviolet absorber, 2.01-chlorotetradecane, and 25 parts of N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 65°C for 12 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and finally dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0042] Step 4: According to the mass fraction, mix 2.6 parts of UV antibacterial agent, 1.5 parts of 3-aminopropyltrimethoxysilane, and 30 parts of toluene in a reaction vessel, stir evenly, and react at 80°C for 6 hours. After the reaction is completed, cool to room temperature, and then remove the solvent by rotary evaporation to obtain the modifier.

[0043] Step 5: Mix 3 parts modifier and 70 parts ethylene-vinyl alcohol copolymer evenly by weight, then put the mixture into a twin-screw extruder and melt extrude at 190°C, cool and granulate to obtain modified barrier layer masterbatch.

[0044] Step 6: According to the mass fraction, 50 parts of modified barrier layer masterbatch, 25 parts of polyethylene heat-sealing layer masterbatch, and 25 parts of polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of the co-extrusion blown film machine and extruded at 200°C through the composite die head to obtain a high barrier tensile composite material. Then, the high barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0045] Example 2

[0046] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0047] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0048] A packaging bag is made of a high-barrier, tensile-resistant composite material, and the specific preparation method is as follows:

[0049] Step 1: By mass fraction, 4.5 parts of pyridine-4-carboxyl chloride, 4.6 parts of p-hydroxystyrene, and 20 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed, and the mixture was reacted at room temperature for 6 hours. After the reaction was completed, the reaction solution was poured into ice water, filtered to obtain a solid, and then the obtained solid was washed with deionized water and dried to obtain pyridinephenol ester.

[0050] Step 2: According to the mass fraction, 5.9 parts of pyridine phenol ester, 6.8 parts of aluminum chloride, and 100 parts of dichlorobenzene are mixed in a reaction vessel, stirred evenly, and reacted at 100℃ for 6 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. Then, the reaction solution is concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0051] Step 3: According to the mass fraction, mix 4.7 parts of ultraviolet absorber, 5.2 parts of 1-chlorododecane, and 50 parts of N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 45°C for 8 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and finally dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0052] Step 4: According to the mass fraction, mix 7.1 parts of UV antibacterial agent, 3.7 parts of 3-aminopropyltriethoxysilane, and 50 parts of toluene in a reaction vessel, stir evenly, and react at 60°C for 4 hours. After the reaction is completed, cool to room temperature, and then remove the solvent by rotary evaporation to obtain the modifier.

[0053] Step 5: Mix 8 parts modifier and 80 parts ethylene-vinyl alcohol copolymer evenly by mass, then put the mixture into a twin-screw extruder and melt extrude at 170°C, cool and granulate to obtain modified barrier layer masterbatch.

[0054] Step 6: According to the mass fraction, 60 parts of modified barrier layer masterbatch, 30 parts of polyethylene heat-sealing layer masterbatch, and 30 parts of polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of the co-extrusion blown film machine and extruded at 230°C through the composite die head to obtain a high barrier tensile composite material. Then, the high barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0055] Example 3

[0056] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0057] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0058] A packaging bag is made of a high-barrier, tensile-resistant composite material, and the specific preparation method is as follows:

[0059] Step 1: According to the mass fraction, 3 parts of pyridine-4-formyl chloride, 2.7 parts of p-hydroxystyrene, and 18 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed and the mixture was reacted at room temperature for 4 hours. After the reaction was completed, the reaction solution was poured into ice water, filtered to obtain a solid, and then the obtained solid was washed with deionized water and dried to obtain pyridinephenol ester.

[0060] Step 2: According to the mass fraction, 4.2 parts of pyridine phenol ester, 4.8 parts of aluminum chloride, and 62 parts of dichlorobenzene are mixed in a reaction vessel, stirred evenly, and reacted at 120°C for 5 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. Then, the reaction solution is concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0061] Step 3: According to the mass fraction, mix 3.6 parts of ultraviolet absorber, 3.9 parts of 1-chlorotridecane, and 45 parts of N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 52°C for 9.5 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and finally dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0062] Step 4: According to the mass fraction, mix 5.4 parts of UV antibacterial agent, 2.8 parts of 3-aminopropyltrimethoxysilane, and 53 parts of toluene in a reaction vessel, stir evenly, and react at 75°C for 4.5 hours. After the reaction is completed, cool to room temperature, and then remove the solvent by rotary evaporation to obtain the modifier.

[0063] Step 5: Mix 5 parts modifier and 75 parts ethylene-vinyl alcohol copolymer evenly by weight, then put the mixture into a twin-screw extruder and melt extrude at 180°C, cool and granulate to obtain modified barrier layer masterbatch.

[0064] Step 6: According to the mass fraction, 55 parts of modified barrier layer masterbatch, 27 parts of polyethylene heat-sealing layer masterbatch, and 28 parts of polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of the co-extrusion blown film machine and extruded at 225°C through the composite die to obtain a high barrier tensile composite material. Then, the high barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0065] Example 4

[0066] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0067] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0068] A packaging bag is made of a high-barrier, tensile-resistant composite material, and the specific preparation method is as follows:

[0069] Step 1: According to the mass fraction, 2.3 parts of pyridine-4-formyl chloride, 2.6 parts of p-hydroxystyrene, and 16 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed and the mixture was reacted at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into ice water, filtered to obtain a solid, and then the obtained solid was washed with deionized water and dried to obtain pyridinephenol ester.

[0070] Step 2: According to the mass fraction, 3.3 parts of pyridine phenol ester, 3.6 parts of aluminum chloride, and 52 parts of dichlorobenzene are mixed in a reaction vessel, stirred evenly, and reacted at 130℃ for 4 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. Then, the reaction solution is concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0071] Step 3: According to the mass fraction, mix 2.9 parts of ultraviolet absorber, 3.2 parts of 1-chlorotetradecane, and 25 parts of N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 48°C for 10 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and finally dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0072] Step 4: According to the mass fraction, mix 5.8 parts of UV antibacterial agent, 3.1 parts of 3-aminopropyltriethoxysilane, and 30 parts of toluene in a reaction vessel, stir evenly, and react at 80°C for 5.5 hours. After the reaction is completed, cool to room temperature, and then remove the solvent by rotary evaporation to obtain the modifier.

[0073] Step 5: Mix 6 parts modifier and 76 parts ethylene-vinyl alcohol copolymer evenly by mass, then put the mixture into a twin-screw extruder and melt extrude at 190°C, cool and granulate to obtain modified barrier layer masterbatch.

[0074] Step 6: According to the mass fraction, 56 parts of modified barrier layer masterbatch, 22 parts of polyethylene heat-sealing layer masterbatch, and 22 parts of polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of the co-extrusion blown film machine and extruded at 220°C through the composite die to obtain a high barrier tensile composite material. Then, the high barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0075] Example 5

[0076] A high-barrier, tensile-strength composite material comprising the following raw materials:

[0077] Modified barrier layer masterbatch, polyethylene heat-sealing layer masterbatch, polyamide substrate layer masterbatch;

[0078] A packaging bag is made of a high-barrier, tensile-resistant composite material, and the specific preparation method is as follows:

[0079] Step 1: According to the mass fraction, 2.7 parts of pyridine-4-formyl chloride, 2.9 parts of p-hydroxystyrene, and 19 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed and the mixture was reacted at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into ice water, filtered to obtain a solid, and then the obtained solid was washed with deionized water and dried to obtain pyridinephenol ester.

[0080] Step 2: According to the mass fraction, 4.1 parts of pyridine phenol ester, 4.5 parts of aluminum chloride, and 54 parts of dichlorobenzene are mixed in a reaction vessel, stirred evenly, and reacted at 130℃ for 4 hours. After the reaction is completed, the mixture is cooled to room temperature and washed with deionized water. Then, the reaction solution is concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0081] Step 3: According to the mass fraction, mix 2.9 parts of ultraviolet absorber, 3.3 parts of 1-chlorotridecane, and 25 parts of N,N-dimethylformamide in a reaction vessel, stir evenly, and react at 48°C for 11 hours. After the reaction is completed, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and finally dry the obtained solid to obtain the ultraviolet antibacterial agent.

[0082] Step 4: According to the mass fraction, mix 6.6 parts of UV antibacterial agent, 3.4 parts of 3-aminopropyltrimethoxysilane, and 30 parts of toluene in a reaction vessel, stir evenly, and react at 80°C for 5.5 hours. After the reaction is completed, cool to room temperature, and then remove the solvent by rotary evaporation to obtain the modifier.

[0083] Step 5: Mix 7 parts modifier and 79 parts ethylene-vinyl alcohol copolymer evenly by mass, then put the mixture into a twin-screw extruder and melt extrude at 190°C, cool and granulate to obtain modified barrier layer masterbatch.

[0084] Step 6: According to the mass fraction, 58 parts of modified barrier layer masterbatch, 21 parts of polyethylene heat-sealing layer masterbatch, and 21 parts of polyamide substrate layer masterbatch are respectively fed into the middle, inner, and outer extruders of the co-extrusion blown film machine and extruded at 220°C through the composite die head to obtain a high barrier tensile composite material. Then, the high barrier tensile composite material is placed on a bag making machine for heat sealing and cutting to obtain a packaging bag.

[0085] Comparative Example 1

[0086] Compared with Example 1, this comparative example only added commercially available o-hydroxybenzophenone UV-9 as an anti-ultraviolet agent to the ethylene-vinyl alcohol copolymer, while the rest of the preparation method and raw materials remained unchanged.

[0087] Experimental Example 1

[0088] The following tests were performed on Examples 1-5 and Comparative Example 1, and the test results are shown in Tables 1-3.

[0089] The antibacterial (Escherichia coli) performance of the samples in Examples 1-5 and the sample in Comparative Example 1 was tested in accordance with the national standard GB / T31402-2023 "Determination of antibacterial activity of plastics and other non-porous materials". The test results are shown in Table 1.

[0090] According to the national standard GB / T16422.2-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 2: Xenon Arc Lamp", the samples of Examples 1-5 and the sample of Comparative Example 1 were subjected to accelerated UV aging (using UVA-340 lamp tube, 0.83W / m² irradiance, 60℃ UV irradiation for 500h) performance tests. The test results are shown in Table 2.

[0091] The peel strength of the samples in Examples 1-5 and the sample in Comparative Example 1 was tested in accordance with the national standard GB / T8808-1988 "Peel Strength Test Method for Flexible Composite Plastic Materials" (peel strength 1 is the PA / modified EVOH layer, peel strength 2 is the modified EVOH / PE layer). The test results are shown in Table 3.

[0092] Table 1

[0093] Antibacterial rate (%) Example 1 90.2 Example 2 90.6 Example 3 90.3 Example 4 90.4 Example 5 90.5 Comparative Example 1 12.7

[0094] Table 2

[0095] Tensile strength retention rate (%) Elongation at break retention rate (%) Example 1 78.2 79.3 Example 2 78.8 81.1 Example 3 78.3 79.4 Example 4 78.5 79.6 Example 5 78.6 79.8 Comparative Example 1 71.4 73.2

[0096] Table 3

[0097] Peel strength 1 (N / 15mm) Peel strength 2 (N / 15mm) Example 1 2.2 1.9 Example 2 2.6 2.4 Example 3 2.3 2.1 Example 4 2.4 2.2 Example 5 2.5 2.3 Comparative Example 1 1.7 1.2

[0098] As shown in Tables 1-3, Examples 1-5 exhibit significantly improved tensile strength and elongation at break compared to Comparative Example 1, demonstrating superior tensile strength and toughness. Furthermore, Examples 1-5 show an antibacterial rate as high as 90.2%-90.6%, far exceeding the 12.7% of Comparative Example 1, achieving an antibacterial effect. Moreover, after UV aging, Examples 1-5 show significantly better retention rates of tensile strength and elongation at break than Comparative Example 1, indicating less brittleness with long-term use. The peel strength of the PA / modified EVOH layer and the modified EVOH / PE layer in Examples 1-5 are also superior to those in Comparative Example 1. This demonstrates that the modifier of this invention solves the defects of traditional EVOH composite packaging, such as weak interlayer adhesion, lack of antibacterial function, and poor UV aging resistance.

[0099] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A high-barrier, stretch-resistant composite material, characterized in that, The high-barrier tensile-resistant composite material comprises the following components: a modified barrier layer master batch, a polyethylene heat-sealing layer master batch, and a polyamide base material layer master batch; The preparation method of the modified barrier layer master batch is as follows: S1, pyridine-4-formyl chloride is subjected to esterification with p-hydroxystyrene to obtain a pyridine phenolic ester; S2, the pyridine phenolic ester is subjected to a Fries rearrangement under the condition of aluminum chloride to obtain an ultraviolet absorber; S3, the ultraviolet absorber is subjected to quaternary ammonium reaction with a long-chain halogenated hydrocarbon to obtain an ultraviolet antibacterial agent; S4, the ultraviolet antibacterial agent is subjected to Michael addition reaction with an amino silane to obtain a modifier; S5, the modifier and ethylene-vinyl alcohol copolymer are uniformly mixed, and then the mixture is melt-extruded and cooled and granulated to obtain the modified barrier layer master batch.

2. The high-barrier, stretch-resistant composite of claim 1, wherein, The mass ratio of the modified barrier layer master batch, the polyethylene heat-sealing layer master batch, and the polyamide base material layer master batch is 50-60:25-30:25-30.

3. The high-barrier, stretch-resistant composite of claim 1, wherein, In S1, the mass ratio of pyridine-4-formyl chloride to p-hydroxystyrene is 1.7-4.5:1.8-4.

6.

4. The high-barrier, stretch-resistant composite of claim 1, wherein, In S2, the mass ratio of the pyridine phenolic ester to aluminum chloride is 2.3-5.9:2.6-6.

8.

5. The high-barrier, stretch-resistant composite of claim 1, wherein, In S3, the mass ratio of the ultraviolet absorber to the long-chain halogenated hydrocarbon is 1.8-4.7:2.0-5.

2.

6. The high-barrier, stretch-resistant composite of claim 1, wherein, In S3, the long-chain halogenated hydrocarbon is at least one of 1-chlorododecane, 1-chlorotridecane, and 1-chlorotetradecane.

7. The high-barrier, stretch-resistant composite of claim 1, wherein, In S4, the mass ratio of the ultraviolet antibacterial agent to the amino silane is 2.6-7.1:1.5-3.

7.

8. The high-barrier, stretch-resistant composite of claim 1, wherein, In S4, the amino silane is at least one of 3-aminopropyl triethoxysilane and 3-aminopropyl trimethoxysilane.

9. The high-barrier, stretch-resistant composite of claim 1, wherein, In S5, the mass ratio of the modifier to the ethylene-vinyl alcohol copolymer is 3-8:70-80.

10. A package, characterized in that The packaging bag is prepared from the high-barrier tensile-resistant composite material, and the specific preparation steps are as follows: The modified barrier layer master batch, the polyethylene heat-sealing layer master batch, and the polyamide base material layer master batch are respectively put into the corresponding extruders in the middle layer, the inner layer, and the outer layer of a co-extrusion film blowing machine, and then extruded and blown into a film at 200-230°C through a head composite die to obtain the high-barrier tensile-resistant composite material, and then the high-barrier tensile-resistant composite material is heat-sealed and cut to obtain the packaging bag.