Food packaging film based on high polymer material and production method thereof

Abstract

The invention relates to the technical field of packaging materials, and discloses a food packaging film based on a high polymer material and a production method thereof, the packaging film is prepared by taking polypropylene as a base material and maleic anhydride grafted polypropylene, an ethylene-vinyl acetate copolymer, a modified antibacterial additive and the like as auxiliary materials through granulation and film blowing processes, the modified antibacterial additive is prepared by modifying the surfaces of mullite fibers with polyester type macromolecular substances, organic transition between the mullite fibers and a polypropylene matrix can be achieved through the organic macromolecular substances, the compatibility between the mullite fibers and the polypropylene matrix is effectively improved, then the stress transfer dispersion effect of the mullite fibers is efficiently utilized, and the antibacterial performance of the mullite fibers is improved. The mechanical strength and the temperature resistance of the packaging film are improved. In addition, rigid cyclopentane and citronellol contained in the polyester type macromolecular modifier structure can further improve the high temperature resistance and antibacterial effect of the packaging film.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, and particularly relates to a food packaging film based on polymer materials and a production method thereof. Background Art

[0002] As an important tool for protecting food quality and extending the shelf life of food, food packaging films play a crucial role in the food industry. At present, most food packaging films are prepared using polymer materials as the base material. Among many polymer materials, polypropylene, as one of the main materials for food packaging films, has many advantages, such as being non-toxic and harmless, light in weight, high in strength, high in transparency, good in moisture barrier property, heat-resistant and cold-resistant, easy to process, and low in cost. It is widely used in the field of food packaging films.

[0003] However, the defects of polypropylene are also very obvious. First of all, the heat resistance performance of polypropylene is poor, resulting in the polypropylene film being easily affected by temperature during use, leading to a decline in performance. This may affect the shelf life and safety of food. In addition, the antibacterial property of polypropylene itself is also poor, which is a relatively obvious disadvantage for food packaging. Therefore, improving the high-temperature resistance of polypropylene and endowing it with excellent antibacterial properties is the key to its further application in the field of food packaging films.

[0004] In the prior art, generally, silver is used as an antibacterial agent to add and modify polypropylene. However, silver itself, as a heavy metal element, is likely to cause great harm to the environment after being discarded. In addition, the antibacterial property of polypropylene can also be improved by adding quaternary ammonium salt antibacterial agents, biological antibacterial agents, etc. However, these types of small molecule antibacterial agents themselves have the phenomenon of migration and volatilization, and it is difficult to achieve long-term antibacterial effect. Based on this, the present invention provides a polypropylene food packaging film, which can solve the problems existing in the prior art. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide a food packaging film based on polymer materials and a production method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A production method of a food packaging film based on polymer materials, wherein the food packaging film is made of the following raw materials by weight:

[0008] 68 - 75 parts of polypropylene, 5 - 12 parts of maleic anhydride grafted polypropylene, 5 - 10 parts of ethylene-vinyl acetate copolymer, 2 - 4.5 parts of modified antibacterial additive, 0.5 - 1 part of antioxidant, 1 - 2 parts of lubricant;

[0009] The preparation method of the food packaging film comprises the following steps:

[0010] First step: Weigh the above raw materials according to the weight parts and get them ready.

[0011] Second step: Add the raw materials into a blender for stirring and mixing, then feed them into an extruder for extrusion granulation to form pellets.

[0012] Third step: Place the obtained pellets in a blown film machine for blow molding, and then through the processes of winding and cutting, it is done.

[0013] As a further scheme of the present invention, the preparation method of the modified antibacterial additive comprises the following steps:

[0014] Step 1: In an ethanol medium, use a silane coupling agent to modify mullite fibers to form modified mullite fibers.

[0015] Step 2: Disperse the modified mullite fibers in a toluene medium, then add 1,1 - cyclopentanediacetic acid and a composite catalyst. After adding, introduce dry nitrogen for protection, raise the temperature to 50 - 60 °C, keep stirring for 2 - 4 h, then continue to add a citronellol - based chain extender, and raise the temperature to 70 - 80 °C. Keep stirring for 12 - 24 h and then cool down and discharge to obtain the modified antibacterial additive.

[0016] As a further scheme of the present invention, the silane coupling agent is any one of 3 - aminopropyltrimethoxysilane, 3 - aminopropyltriethoxysilane or N-(2 - aminoethyl)-3 - aminopropyltrimethoxysilane.

[0017] As a further scheme of the present invention, the composite catalyst is a mixture of dicyclohexylcarbodiimide and 4 - dimethylaminopyridine, and the mass ratio is 1:0.4 - 0.5.

[0018] In the above technical scheme, first, use a silane coupling agent containing an amino group to perform surface modification on mullite fibers to achieve amino modification of mullite fibers and obtain modified mullite fibers. Then, under the action of a composite catalyst, the active carboxyl substituents in the structure of 1,1 - cyclopentanediacetic acid can condense with the amino groups of the modified mullite fibers. Then continue to add a citronellol - based chain extender containing two equivalent hydroxyl substituents in the structure to perform continuous chain - extending condensation with the excessive 1,1 - cyclopentanediacetic acid in the system, so as to achieve the modification of polyester - type macromolecular substances on the surface of mullite fibers and obtain the modified antibacterial additive.

[0019] As a further scheme of the present invention, the specific preparation method of the citronellol - based chain extender is as follows:

[0020] Introduce nitrogen into the reaction kettle. Then, under nitrogen protection, add citronellol and tetrahydrofuran into the reaction kettle, start stirring, wait until a homogeneous reaction solution is formed, and then add glycidol and a phase transfer catalyst into the reaction kettle. After adding, stir and mix evenly, and then heat up to 60 - 65 °C, continuously stir for 2 - 6 h, then remove the solvent by rotary evaporation under reduced pressure, collect the product, and perform purification and post-treatment processes to obtain the product.

[0021] As a further scheme of the present invention, the molar ratio of citronellol to glycidol is 1:1.

[0022] As a further scheme of the present invention, the phase transfer catalyst is any one of tetrabutylammonium bromide, tetramethylammonium bromide, or tetrabutylammonium hydrogensulfate.

[0023] As a further scheme of the present invention, the mass ratio of the modified mullite fiber, 1,1 - cyclopentanediacetic acid, and citronellol - based chain extender is 1:1.5 - 2.5:0.5 - 1.2.

[0024] As a further scheme of the present invention, the antioxidant is selected from at least one of antioxidant 1076 or antioxidant 1010; the lubricant is selected from at least one of zinc stearate, polyethylene wax, or paraffin.

[0025] A food packaging film based on a polymer material is prepared by the above production method.

[0026] Advantages of the present invention:

[0027] In the present invention, a modified antibacterial additive is prepared by modifying a polyester - type macromolecular substance on the surface of mullite fiber. First, as an organic macromolecular substance, the polyester - type macromolecular modifier can achieve an organic transition between the mullite fiber and the polypropylene matrix, effectively improving the compatibility between them. Moreover, during the melt - extrusion process, the molecular chains of the polyester - type macromolecule can extend to various regions of the polypropylene molecular chains, achieving mutual entanglement and interweaving, thereby efficiently utilizing the stress transfer and dispersion effect of the mullite fiber, not only improving the mechanical strength of the packaging film but also improving the heat - resistant performance. In addition, the rigid cyclopentane contained in the structure of the polyester - type macromolecular modifier can improve the stability of the polypropylene molecular chains, further improving the high - temperature resistance of the packaging film. The natural antibacterial agent citronellol in the structure of the polyester - type macromolecular modifier has a good bactericidal effect, thereby endowing the packaging film with excellent antibacterial properties. Moreover, due to the confinement effect of chemical grafting, citronellol cannot volatilize and can exist in the packaging film for a long time, achieving a long - term antibacterial effect.

[0028] Of course, it is not necessary for any product implementing the present invention to simultaneously achieve all the above - mentioned advantages. Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 It is the infrared analysis test chart of citronellol-based chain extender. Specific embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0032] Embodiment 1

[0033] A food packaging film based on polymer materials is made of the following raw materials by weight:

[0034] 68 parts of polypropylene, 5 parts of maleic anhydride grafted polypropylene, 5 parts of ethylene-vinyl acetate copolymer, 2 parts of modified antibacterial additive, 0.5 part of antioxidant 1076, 1 part of lubricant zinc stearate;

[0035] The preparation method of the food packaging film includes the following steps:

[0036] First step, weigh the above raw materials according to the weight parts and prepare them;

[0037] Second step, add the raw materials into a blender and stir and mix, then feed them into an extruder, extrude and granulate to form pellets;

[0038] Third step, place the obtained pellets in a blown film machine, control the temperatures at 160°C, 165°C, 170°C, 170°C, and 165°C in sequence, blow and mold, and then through the processes of winding and cutting, it is ready.

[0039] Embodiment 2

[0040] A food packaging film based on polymer materials is made of the following raw materials by weight:

[0041] 70 parts of polypropylene, 6 parts of maleic anhydride grafted polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 4 parts of modified antibacterial additive, 0.6 part of antioxidant 1010, 1.5 parts of lubricant polyethylene wax;

[0042] The preparation method of the food packaging film comprises the following steps:

[0043] Step 1: Weigh the above raw materials according to the weight parts and get them ready.

[0044] Step 2: Add the raw materials into a blender for stirring and mixing, then feed them into an extruder for extrusion granulation to form pellets.

[0045] Step 3: Place the obtained pellets into a blown film machine, control the temperature at 160°C, 165°C, 170°C, 170°C, 165°C in sequence for blow molding, and then through winding and cutting processes, it is completed.

[0046] Example 3

[0047] A food packaging film based on polymer materials is made of the following raw materials according to the weight parts:

[0048] 75 parts of polypropylene, 12 parts of maleic anhydride grafted polypropylene, 10 parts of ethylene-vinyl acetate copolymer, 4.5 parts of modified antibacterial additive, 1 part of antioxidant 1010, 2 parts of lubricant polyethylene wax;

[0049] The preparation method of the food packaging film comprises the following steps:

[0050] Step 1: Weigh the above raw materials according to the weight parts and get them ready.

[0051] Step 2: Add the raw materials into a blender for stirring and mixing, then feed them into an extruder for extrusion granulation to form pellets.

[0052] Step 3: Place the obtained pellets into a blown film machine, control the temperature at 160°C, 165°C, 170°C, 170°C, 165°C in sequence for blow molding, and then through winding and cutting processes, it is completed.

[0053] The modified antibacterial additive in the above examples is prepared by the following method:

[0054] Step 1: Disperse 1.5 g of mullite fiber in an ethanol medium, add 0.8 g of 3-aminopropyltriethoxysilane to the formed dispersion liquid. After adding, raise the temperature to 65°C, stir for 4 h, then centrifuge out the solid material, and after washing and vacuum drying treatment, the modified mullite fiber can be formed.

[0055] Step 2: Disperse 1.2 g of modified mullite fiber in toluene medium, then add 2.8 g of 1,1-cyclopentanediacetic acid, 0.5 g of dicyclohexylcarbodiimide and 0.2 g of 4-dimethylaminopyridine. After adding, introduce dry nitrogen for protection, raise the temperature to 55 °C, keep stirring for 3 h, then continue to add 0.8 g of citronellol-based chain extender, and raise the temperature to 75 °C. Keep stirring for 18 h, then cool down and discharge to obtain the modified antibacterial additive.

[0056] The specific preparation method of the citronellol-based chain extender is as follows:

[0057] Introduce nitrogen into the reaction kettle. Then, under the protection of nitrogen, add 0.2 g of citronellol and tetrahydrofuran into the reaction kettle, start stirring. After forming a homogeneous reaction solution, add 0.09 g of glycidol and 0.01 g of tetrabutylammonium bromide into the reaction kettle. After adding, stir and mix evenly, then raise the temperature to 65 °C, keep stirring for 3 h, then remove the solvent by rotary evaporation under reduced pressure, collect the product, and carry out the purification treatment process to obtain the product.

[0058] Figure 1 This is the infrared analysis test chart of the citronellol-based chain extender. The characteristic absorption peak at 3428 cm -1 is the characteristic absorption peak of the hydroxyl group, and the characteristic absorption peak at 1042 cm -1 is the carbon-oxygen characteristic absorption peak of the ether bond, and no obvious characteristic absorption peak of the epoxy group is observed in the figure.

[0059] Comparative Example 1

[0060] A food packaging film based on polymer materials is made from the following raw materials by weight:

[0061] 70 parts of polypropylene, 6 parts of maleic anhydride grafted polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 4 parts of mullite fiber, 0.6 part of antioxidant 1010, 1.5 parts of lubricant polyethylene wax;

[0062] The preparation method of the food packaging film includes the following steps:

[0063] Step 1: Weigh the above raw materials according to the weight parts and prepare them.

[0064] Step 2: Add the raw materials into a blender and stir and mix them, then feed them into an extruder to extrude and granulate to form pellets.

[0065] Step 3: Place the prepared pellets in a blown film machine, control the temperature at 160 °C, 165 °C, 170 °C, 170 °C, 165 °C in sequence, blow and mold, and then through the winding and cutting processes to obtain the product.

[0066] Comparative Example 2

[0067] A food packaging film based on polymer materials is made from the following raw materials by weight:

[0068] 70 parts of polypropylene, 6 parts of maleic anhydride grafted polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 4 parts of mullite fiber, 0.6 parts of antioxidant 1010, and 1.5 parts of lubricant polyethylene wax;

[0069] The preparation method of the food packaging film includes the following steps:

[0070] First step: Weigh each of the above raw materials according to the weight parts and get them ready.

[0071] Second step: Add each raw material into a blender and stir and mix, then feed it into an extruder for extrusion granulation to form pellets.

[0072] Third step: Place the obtained pellets in a blown film machine, control the temperature at 160°C, 165°C, 170°C, 170°C, 165°C in sequence, blow and mold, and then through the processes of winding and cutting, it is done.

[0073] Test example

[0074] According to the standard GB / T 1040.2-2022, the tensile properties of the packaging films in the examples and comparative examples were tested; after placing samples of the same batch in an oven at 150°C for accelerated aging treatment for 48 h, take them out and conduct tensile property tests to evaluate their aging resistance.

[0075] According to the standard QB / T 2591-2003, the antibacterial properties of the packaging films in the examples and comparative examples were tested, and the selected strain was Escherichia coli.

[0076] The test results are recorded in the following table:

[0077]

[0078] In this article, specific examples are used to illustrate the principles and implementation modes of the present invention. The description of the above embodiments is only for helping to understand the method and its core idea of the present invention, including the best mode, and also enables 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 of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements approximately the same as the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A production method of a food packaging film based on polymer materials, characterized in that, The food packaging film is made of the following raw materials by weight: 68 - 75 parts of polypropylene, 5 - 12 parts of maleic anhydride grafted polypropylene, 5 - 10 parts of ethylene - vinyl acetate copolymer, 2 - 4.5 parts of modified antibacterial additive, 0.5 - 1 part of antioxidant, 1 - 2 parts of lubricant; The preparation method includes the following steps: First step, weigh each of the above raw materials according to the parts by weight and get them ready; Second step, add each raw material into a blender and stir - mix, then feed it into an extruder for extrusion granulation to form pellets; Third step, place the obtained pellets in a blown - film machine, blow - mold them by heating the blown - film machine, and then through the processes of winding and cutting, it is done.

2. The production method of a food packaging film based on polymer materials according to claim 1, characterized in that The preparation method of the modified antibacterial additive includes the following steps: Step one, in an ethanol medium, use a silane coupling agent to modify mullite fibers to form modified mullite fibers; Step two, disperse the modified mullite fibers in a toluene medium, then add 1,1 - cyclopentanediacetic acid and a composite catalyst. After adding, introduce dry nitrogen for protection, raise the temperature to 50 - 60 °C, keep stirring for 2 - 4 h, then continue to add a citronellol - based chain extender, and raise the temperature to 70 - 80 °C, continuously keep stirring for 12 - 24 h, then cool down and discharge to obtain the modified antibacterial additive.

3. The production method of a food packaging film based on polymer materials according to claim 2, characterized in that, The silane coupling agent is any one of 3 - aminopropyltrimethoxysilane, 3 - aminopropyltriethoxysilane, or N - (2 - aminoethyl) - 3 - aminopropyltrimethoxysilane.

4. The production method of a food packaging film based on polymer materials according to claim 2, characterized in that, The composite catalyst is a mixture of dicyclohexylcarbodiimide and 4 - dimethylaminopyridine, and the mass ratio is 1:0.4 - 0.

5.

5. The production method of a food packaging film based on polymer materials according to claim 2, characterized in that, The specific preparation method of the citronellol - based chain extender is as follows: Introduce nitrogen into the reaction kettle, then under nitrogen protection, add citronellol and tetrahydrofuran into the reaction kettle, start stirring. After forming a uniform reaction solution, add glycidol and a phase - transfer catalyst into the reaction kettle. After adding, stir and mix evenly, then raise the temperature to 60 - 65 °C, keep stirring for 2 - 6 h, then remove the solvent by rotary evaporation under reduced pressure, collect the product, and through the purification process, it is done.

6. The production method of a food packaging film based on polymer materials according to claim 5, wherein, The molar ratio of citronellol to glycidol is 1:

1.

7. A production method of a food packaging film based on polymer materials according to claim 5, characterized in that, The phase - transfer catalyst is any one of tetrabutylammonium bromide, tetramethylammonium bromide, or tetrabutylammonium hydrogensulfate.

8. The production method of a food packaging film based on polymer materials according to claim 2, characterized in that, The mass ratio of the modified mullite fibers, 1,1 - cyclopentanediacetic acid, and citronellol - based chain extender is 1:1.5 - 2.5:0.5 - 1.

2.

9. The production method of a food packaging film based on polymer materials according to claim 1, characterized in that, The antioxidant is selected from at least one of antioxidant 1076 or antioxidant 1010; the lubricant is selected from at least one of zinc stearate, polyethylene wax, or paraffin.

10. A food packaging film based on polymer materials, characterized in that, Prepared by the production method according to any one of claims 1 - 9.

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