A kind of food packaging film with easy linear tearing and its preparation process

Abstract

The invention relates to the technical field of multifunctional food packaging materials, and discloses an easy-to-straight-line-tear type food packaging film and a preparation process thereof, comprising: synthesizing an antibacterial ligand containing multiple carboxyl functional groups, and preparing an antibacterial agent through coordination with a metal ion having an antibacterial function; taking the antibacterial agent as a functional modification raw material, and compounding it with a polyvinyl alcohol resin under the action of a compatibilizer to prepare an antibacterial composition; taking a nylon resin as a raw material and the antibacterial composition as a filler, and preparing an easy-to-straight-line-tear type food packaging film through a blending granulation, a blow molding film and a biaxial stretching process, wherein the film product exhibits an obvious inhibitory effect on Staphylococcus aureus and Escherichia coli, and the average tearing force thereof is less than 2N, and the tearing deviation thereof is less than 10%, and the film belongs to an easy-to-straight-line-tear type material, and the sanitary performance thereof also meets the technical standards of food packaging materials stipulated in national standards.

Description

Technical Field

[0001] The invention relates to the technical field of multifunctional food packaging materials, in particular to an easy-to-straight-line-tear type food packaging film and a preparation process thereof. Background Art

[0002] In the food industry, some preservation technologies are often used to prevent food from spoiling and maintain the quality of food storage. However, the preservatives in the existing technology may cause environmental pollution problems. Therefore, antibacterial packaging materials that can inhibit the growth of microorganisms and extend the shelf life of food have become a research hotspot in food packaging.

[0003] The straight tear film can effectively solve the problems of conventional composite bags that are difficult to cut and tear, as well as the problem that straight cracks cannot be produced but curved and inclined cracks can easily lead to leakage of contents when the bag is torn, especially when the contents are liquid or powder, which can easily cause unnecessary trouble.

[0004] How to improve the properties of food packaging materials to achieve the technical goal of delaying the deterioration of food quality on the one hand, and effectively improve the linear tearing performance of food packaging materials on the other hand, has become a research direction for food packaging materials. Summary of the invention

[0005] The invention provides a preparation process of an easy-to-straight-line-tear type food packaging film, wherein the film product prepared thereby has very excellent antibacterial ability, its easy-to-straight-line-tear performance meets the technical requirements specified in the industry standards, and its sanitary performance also meets the technical standards of food packaging materials specified in the national standards.

[0006] A linearly tearable food packaging film comprises the following raw materials in parts by weight:

[0007] 75-90 parts of nylon resin;

[0008] 5-20 parts of antibacterial composition;

[0009] 0.1-2 parts of antioxidant;

[0010] 0.1-1 part of anti-ultraviolet agent;

[0011] 1-5 parts of plasticizer;

[0012] The formula of the antibacterial composition is: 60-80wt% polyvinyl alcohol resin PVA, 5-25wt% antibacterial agent and 10-20wt% glycerol;

[0013] The antibacterial agent is prepared by a coordination reaction between an antibacterial ligand a containing a tetracarboxyl functional group and a metal ion having an antibacterial function, or by a coordination reaction between an antibacterial ligand a containing a tetracarboxyl functional group and an antibacterial ligand b containing an octacarboxyl functional group and a metal ion having an antibacterial function;

[0014] The mass ratio of the antibacterial ligand a containing tetracarboxyl functional groups to the antibacterial ligand b containing octacarboxyl functional groups is 1:(0.1-1).

[0015] Preferably, the preparation method of the antibacterial ligand a is:

[0016] The Schiff base reaction mechanism is used to generate a dibromo monomer through a condensation reaction between the carbonyl functional group of 4,4'-dibromobenzyl and the amino functional group of o-phenylenediamine.

[0017] Using the Suzuki coupling reaction mechanism, under alkaline conditions, a palladium catalyst catalyzes the coupling reaction between the dibromo monomer and 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate a tetraester monomer.

[0018] In the presence of sodium hydroxide, the ester functional groups of the tetraester monomer undergo hydrolysis to generate antibacterial ligand a.

[0019] Preferably, the preparation method of the antibacterial ligand b is:

[0020] The Schiff base reaction mechanism is used to generate tetrabromo monomers through condensation reaction between the carbonyl functional group of 4,4'-dibromobenzyl and the amino functional group of 1,2,4,5-benzenetetramine.

[0021] Using the Suzuki coupling reaction mechanism, under alkaline conditions, the tetrabromo monomer is catalyzed by a palladium catalyst to undergo a coupling reaction with 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate an octaester monomer.

[0022] In the presence of sodium hydroxide, the ester functional group of the octaester monomer undergoes a hydrolysis reaction to generate an antibacterial ligand b.

[0023] Preferably, the alkaline condition is one of potassium carbonate, sodium carbonate, cesium carbonate, and potassium phosphate;

[0024] Preferably, the palladium catalyst is one of palladium acetate, tris(dibenzylideneacetone)dipalladium, and tetrakis(triphenylphosphine)palladium.

[0025] Preferably, the metal ion is Ag + , Cu 2+ 、Ti 2+ 、Zn 2+ One of them.

[0026] Preferably, the antioxidant is one or a combination of more than one of antioxidant 168, antioxidant 626, and antioxidant 1010;

[0027] Preferably, the anti-ultraviolet agent is one or a combination of anti-ultraviolet agent UV-329, anti-ultraviolet agent UV-326, and anti-ultraviolet agent UV-531;

[0028] Preferably, the plasticizer is triethyl citrate plasticizer or tributyl citrate plasticizer;

[0029] Preferably, the thickness of the easy linear tearing food packaging film is 20-50 μm.

[0030] A preparation process of an easy-to-straight-line tearing food packaging film comprises the following steps:

[0031] Step 1, preparing antibacterial nylon masterbatch: preparing ingredients according to the formula of the easy-to-tear linear food packaging film, adding the raw materials into a high-speed mixer and mixing them evenly, extruding and granulating them through a twin-screw extruder, and drying to obtain the antibacterial nylon masterbatch;

[0032] Step 2, preparing a food packaging film that is easy to tear in a straight line: adding the antibacterial nylon masterbatch prepared in step 1 to a single-screw extruder film blowing machine, using the upward blowing method to blow mold the film, and then fixing it on the fixture of a biaxial tensile testing machine, using a synchronous stretching process to obtain a food packaging film that is easy to tear in a straight line.

[0033] Preferably, the process parameters of the biaxial stretch testing machine are set as follows: stretching temperature 140-160°C, preheating time 3-8s, shaping temperature 180-210°C, shaping time 0.5-3min, transverse stretching multiple 3-5 times, longitudinal stretching multiple 3-5 times.

[0034] Beneficial effects: The present invention first designs and synthesizes an antibacterial ligand containing multiple carboxyl functional groups, and prepares an antibacterial agent through coordination with a metal ion having an antibacterial function; then, the antibacterial agent is used as a functional modification raw material, and is compounded with a polyvinyl alcohol resin under the action of a compatibilizer, glycerol, to prepare an antibacterial composition;

[0035] With nylon resin as raw material and antibacterial composition as filler, a food packaging film that is easy to tear in a straight line is prepared through blending granulation, blow molding and biaxial stretching process. On the one hand, the film product shows obvious inhibitory effect on Staphylococcus aureus and Escherichia coli. On the other hand, the average tearing force is <2N and the tearing deviation is <10%, which is an easy linear tearing material. DETAILED DESCRIPTION

[0036] Experimental Example 1:

[0037] The antibacterial ligand a is prepared by the following steps:

[0038] Step 1: Using the Schiff base reaction mechanism, the carbonyl functional group of 4,4'-dibromobenzyl reacts with the amino functional group of o-phenylenediamine to generate a dibromo monomer, the chemical structure of which is: ;

[0039] Step 2: Using the Suzuki coupling reaction mechanism, under alkaline conditions, the palladium catalyst catalyzes the coupling reaction between the dibromo monomer and 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate a tetraester monomer, the chemical structure of which is:

[0040] ;

[0041] The alkaline condition is one of potassium carbonate, sodium carbonate, cesium carbonate, and potassium phosphate. In this experimental example, sodium carbonate is used. The palladium catalyst is one of palladium acetate, tris(dibenzylideneacetone)dipalladium, and tetrakis(triphenylphosphine)palladium. In this experimental example, tetrakis(triphenylphosphine)palladium is used.

[0042] Step 3: In the presence of sodium hydroxide, the ester functional group of the tetraester monomer undergoes a hydrolysis reaction to generate an antibacterial ligand a, whose chemical structure is:

[0043] ;

[0044] The specific experimental steps for preparing antibacterial ligand a are as follows:

[0045] 3.7 g 4,4'-dibromobenzyl, 1.1 g o-phenylenediamine and 30 mL acetic acid were added to a three-necked flask, stirred at room temperature until all dissolved, then heated to 105°C and stirred for 3 h, cooled to room temperature, repeatedly washed with methanol, filtered, and vacuum dried to obtain a dibromo monomer;

[0046] 2.2 g of dibromo monomer, 3.2 g of 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester, 2.1 g of anhydrous sodium carbonate, 50 mL of 1,4-dioxane and 20 mL of deionized water were added to a three-necked flask, and stirred at room temperature until all dissolved. Then, under nitrogen protection and mechanical stirring, 10 mL of tetrakis(triphenylphosphine)palladium solution (prepared with 1.5 g of tetrakis(triphenylphosphine)palladium and 10 mL of 1,4-dioxane) was added to the three-necked flask, and the temperature was raised to 100° C. and stirred under reflux for reaction for 6 h, and then cooled to room temperature, extracted with dichloromethane, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation to obtain a tetraester monomer;

[0047] 2.3 g of tetraester monomer, 1.9 g of sodium hydroxide, 20 mL of deionized water and 30 mL of methanol were added to a three-necked flask, stirred at room temperature until all dissolved, then heated to 80°C, stirred and refluxed for 12 h, cooled to room temperature, and rotary evaporated to remove methanol. Concentrated hydrochloric acid was added dropwise to adjust the pH to 1, centrifuged, washed with methanol and deionized water in turn, and vacuum dried to obtain antibacterial ligand a;

[0048] The nuclear magnetic resonance hydrogen spectrum of the antibacterial ligand a is characterized as follows: 1 H NMR (CDCl3, 400MHz) δ: 7.57-7.59 (t, 2H), 7.67-7.69 (d, 4H), 7.92-7.97 (m, 6H), 8.20 (s, 4H).

[0049] Experimental Example 2:

[0050] The antibacterial ligand b is prepared by the following steps:

[0051] Step 1: Using the Schiff base reaction mechanism, the carbonyl functional group of 4,4'-dibromobenzyl reacts with the amino functional group of 1,2,4,5-benzenetetramine to generate a tetrabromo monomer, the chemical structure of which is:

[0052] ;

[0053] Step 2: Using the Suzuki coupling reaction mechanism, under alkaline conditions, the palladium catalyst catalyzes the coupling reaction between the tetrabromo monomer and 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate an octaester monomer, the chemical structure of which is:

[0054] ;

[0055] The alkaline condition is one of potassium carbonate, sodium carbonate, cesium carbonate, and potassium phosphate. In this experimental example, sodium carbonate is used. The palladium catalyst is one of palladium acetate, tris(dibenzylideneacetone)dipalladium, and tetrakis(triphenylphosphine)palladium. In this experimental example, tetrakis(triphenylphosphine)palladium is used.

[0056] Step 3: In the presence of sodium hydroxide, the ester functional group of the octaester monomer undergoes a hydrolysis reaction to generate an antibacterial ligand b, whose chemical structure is:

[0057] ;

[0058] The specific experimental steps for preparing antibacterial ligand b refer to the preparation experiment of antibacterial ligand a, and the only difference is that 0.7g 1,2,4,5-benzenetetramine is used to replace 1.1g o-phenylenediamine, 2.0g tetrabromo monomer is used to replace 2.2g dibromo monomer, and 2.1g octaester monomer is used to replace 2.3g tetraester monomer;

[0059] The nuclear magnetic resonance hydrogen spectrum of the antibacterial ligand b is characterized as follows: 1 H NMR (CDCl3, 400MHz) δ: 7.67-7.69 (d, 8H), 7.96-7.98 (d, 8H), 8.23 ​​(s, 8H), 8.59 (s, 2H).

[0060] Experimental Example 3:

[0061] Preparation of antibacterial agent I: by reacting antibacterial ligand a with Cu 2+ A coordination reaction occurred to prepare the antibacterial agent I. The specific experimental steps were as follows: 6.2 g of antibacterial ligand a and 5.4 g of copper nitrate were dissolved in a mixed solution consisting of 80 mL of deionized water and 20 mL of N,N-dimethylformamide, and the mixture was sealed in a Teflon-lined stainless steel autoclave after ultrasonication for 30 min, and the mixture was heated to 120 °C for 24 h, cooled to room temperature, and centrifuged at 8000 r / min for 15 min, and redispersed with deionized water, centrifuged, and vacuum dried to obtain the antibacterial agent I.

[0062] Preparation of antibacterial agent II: by mixing equal masses of antibacterial ligand a and antibacterial ligand b with Cu 2+ A coordination reaction occurs to prepare antibacterial agent II, and the specific experimental steps thereof differ from those of antibacterial agent I only in that 6.2 g of antibacterial ligand a is replaced by 3.1 g of antibacterial ligand a and 3.1 g of antibacterial ligand b.

[0063] Experimental Example 4:

[0064] The specific process of preparing the antibacterial composition I is as follows:

[0065] The formula of the antibacterial composition I is: 70wt% polyvinyl alcohol resin PVA (purchased from Jining Tangyi Chemical Co., Ltd., brand 235), 15wt% antibacterial agent I and 15wt% glycerol;

[0066] The specific experimental steps for preparing the antibacterial composition I are as follows: 7 g of polyvinyl alcohol resin PVA, 1.5 g of glycerol and 100 mL of deionized water are added to a three-necked flask, heated to 90°C and stirred to dissolve for 4 h, polyvinyl alcohol mother liquor is prepared, cooled to 70°C, 10 mL of a deionized water solution containing 1.5 g of antibacterial agent I is added to the three-necked flask, stirred at 70°C for reaction for 5 h, poured into a glass dish, and vacuum dried at 60°C for 8 h to obtain the antibacterial composition I;

[0067] Preparation of antibacterial composition II: Compared with antibacterial composition I, the only difference is that antibacterial agent II is used to replace antibacterial agent I. Embodiment 1:

[0068] A linearly tearable food packaging film comprises the following raw materials in parts by weight:

[0069] 84 parts of nylon resin (purchased from Zhuzhou Times New Materials Technology Co., Ltd., brand name XCGA035);

[0070] 12 parts of antimicrobial composition;

[0071] 0.7 parts of antioxidant 168;

[0072] 0.8 parts of antioxidant 1010;

[0073] 0.5 parts of anti-ultraviolet agent UV-329;

[0074] 2 parts triethyl citrate plasticizer;

[0075] Wherein, the antibacterial composition is antibacterial composition I or antibacterial composition II. Embodiment 2:

[0076] A preparation process of an easy-to-straight-line tearing food packaging film comprises the following specific steps:

[0077] Step 1, preparing antibacterial nylon masterbatch: according to the formula of the easy-to-tear linear food packaging film, the ingredients are prepared, the raw materials are added into a high-speed mixer and mixed evenly, extruded into granules by a twin-screw extruder, and vacuum dried at 80° C. for 6 hours to obtain the antibacterial nylon masterbatch;

[0078] Among them, the process parameters of the twin-screw extruder are set as follows: the temperatures of zones 1-6 are 190°C, 200°C, 220°C, 250°C, 260°C, and 255°C, respectively, and the speed is 400r / min;

[0079] Step 2, preparing an easy-to-straight-line-tear food packaging film: adding the antibacterial nylon masterbatch prepared in step 1 to a single-screw extruder film blowing machine, using an upward blowing method to blow-mold the film, and then fixing it on the fixture of a biaxial tensile testing machine, using a synchronous stretching process to obtain a 50 μm easy-to-straight-line-tear food packaging film;

[0080] The process parameters of the single screw extruder film blowing machine are as follows: the temperatures of zones 1-3 are 200°C, 220°C, and 255°C, the rotation speed is 50 r / min, the pulling speed is 6 m / min, the die diameter of the film blowing machine is 65 mm, and the blow-up ratio is 2.5; the process parameters of the biaxial tensile testing machine are as follows: stretching temperature is 150°C, preheating time is 5 s, setting temperature is 200°C, setting time is 1 min, and stretching multiple is 3.5 (transverse) × 3.5 (longitudinal);

[0081] When the antibacterial composition is antibacterial composition I, the prepared film product is recorded as easy-to-tear linear food packaging film I;

[0082] When the antibacterial composition is antibacterial composition II, the prepared film product is recorded as easy-to-straight-line-tear food packaging film II. Embodiment three:

[0083] Preparation of easy-to-straight-line-tear food packaging film III: The preparation process thereof differs from that of easy-to-straight-line-tear food packaging film I only in that the formula of the antibacterial composition is: 80wt% polyvinyl alcohol resin PVA, 5wt% antibacterial agent I and 15wt% glycerol. Embodiment 4:

[0084] Preparation of easy-to-straight-line-tear food packaging film IV: The difference between its preparation process and that of easy-to-straight-line-tear food packaging film I is that the formula of the antibacterial composition is: 60wt% polyvinyl alcohol resin PVA, 25wt% antibacterial agent I and 15wt% glycerol.

[0085] Comparative Example:

[0086] Preparation of packaging film: Compared with the easy linear tearing type food packaging film I, the only difference is that the antibacterial composition I is not used in the formula.

[0087] Performance Test:

[0088] 1. Linear tearing performance test:

[0089] (1) Tear resistance: The tear strength test of the sample was carried out in accordance with GB / T 16578.1-2008 "Determination of tear resistance of plastic film and sheeting Part 1: Trouser tear method". The specific test steps are as follows: a 75 mm long straight cut was made in the middle of the 50 mm dimension of a 150 mm × 50 mm sample, and then the sample was clamped on an Instron 5565000 material testing machine. The tear strength test item was selected for the test, and the longitudinal and transverse tear strengths of the sample were recorded, and the average tear force of the sample was calculated;

[0090] (2) Linear tearing performance: A crack is cut in the middle of a sample with a length of L and a width of W in the width direction. The film is torn at a uniform speed along the crack direction, and the width W' at the other end of the film is measured. The tearing deviation of the sample is calculated as follows:

[0091] Tearing deviation (%) = (W / 2-W') / (W / 2) × 100%;

[0092] 2. Antibacterial performance test:

[0093] The antibacterial performance test was carried out using an MJ-250I mold incubator. The specific test steps were as follows: the sample was cut into a disc with a diameter of 6 mm, irradiated with ultraviolet light for 2 h to fully sterilize, and then 100 μL of bacterial solution (concentration of 1.0×10 6 CFU / mL), place the sterile sample flat on the culture medium, place it in an incubator at 37℃ and invert it for 24h, and observe the bacterial growth on the film surface and the diameter of the inhibition ring;

[0094] The bacterial liquid was ATCC6538 Staphylococcus aureus and ATCC25922 Escherichia coli purchased from Shanghai Luwei Technology Co., Ltd.

[0095] 3. Mechanical properties test:

[0096] According to GB / T 1040.1-2018 "Determination of tensile properties of plastics", a 150 mm × 20 mm sample (sampled along the film blowing direction) at room temperature was fixed on an Instron 5565 universal tensile testing machine and subjected to a tensile test at a tensile rate of 5 mm / min.

[0097] 4. Hygienic performance test:

[0098] The hygienic properties of the samples were tested in accordance with GB / T 5009.60-2003 "Analysis Method for Hygienic Standards of Polyethylene, Polystyrene and Polypropylene Molding Products for Food Packaging". The physical and chemical indicators of the experimental results were based on GB / T 5009.58-2003 "Analysis Method for Hygienic Standards of Polyethylene Resins for Food Packaging".

[0099] The above experimental results are shown in Table 1-2 below.

[0100] Table 1 Performance test results of easy linear tearing food packaging film

[0101]

[0102] Table 2 Performance test results of easy linear tearing food packaging film II

[0103]

[0104] By comprehensively analyzing the above experimental results, the following conclusions can be drawn:

[0105] Conclusion 1: Referring to national industry standards and enterprise users' usage requirements:

[0106] When the tearing force is ≤2N, the tearing performance is considered to be very good;

[0107] When the tear deviation is <10%, the straight-line tear performance is considered very good;

[0108] When 10%≤tear deviation≤30%, the linear tearing property is considered good;

[0109] When the tear deviation is >30%, the straight-line tear performance is considered poor;

[0110] Accordingly, the food packaging film products of the easy linear tearing type prepared by the present invention have met the technical requirements of very good linear tearing properties stipulated in the industry standards, and have met the easy tearing performance standards, and are materials of the easy linear tearing type;

[0111] Conclusion 2: The easy-to-straight-line tearing food packaging film product prepared by the present invention exhibits a significant inhibitory effect on Staphylococcus aureus and Escherichia coli, that is, it has excellent antibacterial ability;

[0112] Conclusion 3: The easy-to-straight-line-tear food packaging film product prepared by the present invention has excellent comprehensive performance, and its hygienic performance meets the requirements of national standards, and can be used in food packaging.

Claims

1. A linearly tearable food packaging film, characterized in that: The invention comprises the following raw materials in parts by weight: 75-90 parts of nylon resin; 5-20 parts of antibacterial composition; 0.1-2 parts of antioxidant; 0.1-1 part of anti-ultraviolet agent; 1-5 parts of plasticizer; The formula of the antibacterial composition is: 60-80wt% polyvinyl alcohol resin PVA, 5-25wt% antibacterial agent and 10-20wt% glycerol; The antibacterial agent is a tetracarboxyl functional group-containing antibacterial ligand a and a metal ion Cu with antibacterial function. 2+ It is prepared by coordination reaction; Alternatively, the antibacterial agent can be used to synergize with the metal ion Cu with antibacterial function through the antibacterial ligand a containing a tetracarboxyl functional group and the antibacterial ligand b containing an octacarboxyl functional group. 2+ The coordination reaction is carried out to obtain the product; wherein the mass ratio of the antibacterial ligand a to the antibacterial ligand b is 1:(0.1-1); The chemical structural formula of the antibacterial ligand a is: ； The chemical structural formula of the antibacterial ligand b is: 。 2. The easy linear tearing food packaging film according to claim 1, characterized in that: The preparation method of the antibacterial ligand a is: The Schiff base reaction mechanism is used to generate a dibromo monomer through a condensation reaction between the carbonyl functional group of 4,4'-dibromobenzyl and the amino functional group of o-phenylenediamine. Using the Suzuki coupling reaction mechanism, under alkaline conditions, a palladium catalyst catalyzes the coupling reaction between the dibromo monomer and 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate a tetraester monomer. In the presence of sodium hydroxide, the ester functional groups of the tetraester monomer undergo hydrolysis to generate antibacterial ligand a.

3. The easy linear tearing food packaging film according to claim 1, characterized in that: The preparation method of the antibacterial ligand b is: The Schiff base reaction mechanism is used to generate tetrabromo monomers through condensation reaction between the carbonyl functional group of 4,4'-dibromobenzyl and the amino functional group of 1,2,4,5-benzenetetramine. Using the Suzuki coupling reaction mechanism, under alkaline conditions, the tetrabromo monomer is catalyzed by a palladium catalyst to undergo a coupling reaction with 2,6-bis(methoxycarbonyl)pyridine-4-boronic acid pinacol ester to generate an octaester monomer. In the presence of sodium hydroxide, the ester functional group of the octaester monomer undergoes a hydrolysis reaction to generate an antibacterial ligand b.

4. The easy linear tearing food packaging film according to claim 2 or 3, characterized in that: The base in the alkaline condition is one of potassium carbonate, sodium carbonate, cesium carbonate, and potassium phosphate; The palladium catalyst is one of palladium acetate, tris(dibenzylideneacetone)dipalladium and tetrakis(triphenylphosphine)palladium.

5. The easy linear tearing food packaging film according to claim 1, characterized in that: The thickness of the easy linear tearing food packaging film is 20-50 μm.

6. The process for preparing the easy linear tearing food packaging film according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1, preparing antibacterial nylon masterbatch: preparing ingredients according to the formula of the easy-to-tear linear food packaging film, adding the raw materials into a high-speed mixer and mixing them evenly, extruding and granulating them through a twin-screw extruder, and drying to obtain the antibacterial nylon masterbatch; Step 2, preparing a food packaging film that is easy to tear in a straight line: adding the antibacterial nylon masterbatch prepared in step 1 to a single-screw extruder film blowing machine, using the upward blowing method to blow mold the film, and then fixing it on the fixture of a biaxial tensile testing machine, using a synchronous stretching process to obtain a food packaging film that is easy to tear in a straight line.

7. The process for preparing the easy linear tearing food packaging film according to claim 6, characterized in that: The process parameters of the biaxial stretching test machine are set as follows: stretching temperature 140-160° C., setting temperature 180-210° C., setting time 0.5-3 min, transverse stretching multiple 3-5 times, and longitudinal stretching multiple 3-5 times.

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