A puncture-resistant pof film and a method for making the same

Abstract

The present application relates to the technical field of packaging materials, and relates to a puncture-resistant POF film and a preparation method thereof. The POF film adopts a three-layer co-extrusion structure, the outer layer comprises polyethylene and high-transparency modified polyamide masterbatch, the middle layer comprises polypropylene and high-transparency modified polyamide masterbatch, and the inner layer is a polyethylene layer. The high-transparency modified polyamide masterbatch comprises tool nylon matrix, organic montmorillonite, nucleating agent and reactive compatibilizer. The preparation method comprises the following steps: respectively melting and plasticizing the raw materials of each layer, co-extrusion blowing film, blowing, cooling and shaping, corona treatment and winding. The present application introduces modified polyamide masterbatch into the outer layer and the middle layer of the POF film, improves the puncture resistance of the POF film while basically maintaining high transparency and good heat shrinkage performance, and solves the problem that the traditional POF film is easy to be punctured.

Description

Technical Field

[0001] This application relates to the field of packaging materials technology, and in particular to a POF film with high puncture resistance and its preparation method. Background Technology

[0002] Polyolefin heat-shrinkable film (POF film) is widely used in packaging for food, daily necessities, and electronic products due to its excellent transparency, high shrinkage rate, and environmentally friendly and non-toxic properties. However, traditional POF film has significant shortcomings in puncture resistance. Existing POF films are mainly made from polyolefin materials such as polyethylene and polypropylene through a multi-layer co-extrusion process. Although these materials have good flexibility and heat-shrinkability, their relatively regular molecular chain structure and weak intermolecular forces result in limited puncture resistance. When packaging sharp objects or subjected to external impact, the film is easily punctured and damaged, thus affecting the sealing and protective performance of the packaging.

[0003] Currently, some improvements have been made to the puncture resistance of POF films. The main improvement directions include increasing the film thickness to improve puncture resistance, but this will affect the heat shrinkage performance; or adding some inorganic fillers to the polyolefin matrix, but this will lead to increased brittleness and decreased transparency of the film.

[0004] To address the aforementioned issues, a new type of POF film is needed that significantly improves puncture resistance while maintaining the film's excellent performance, and simultaneously preserves transparency, heat shrinkage rate, and processability to meet the needs of high-end packaging applications. Summary of the Invention

[0005] To address the problem of puncture resistance in existing POF membranes, the purpose of this application is to provide a puncture-resistant POF membrane and its preparation method.

[0006] In a first aspect, this application provides a puncture-resistant POF film, which consists of a three-layer co-extruded structure comprising an outer layer, a middle layer, and an inner layer. The outer layer comprises polyethylene and a high-transparency modified polyamide masterbatch, the middle layer comprises polypropylene and a high-transparency modified polyamide masterbatch, and the inner layer comprises polyethylene. The high-transparency modified polyamide masterbatch comprises a copolymerized nylon matrix, an organo-modified montmorillonite dispersed in the copolymerized nylon matrix, a nucleating agent, and a reactive compatibilizer.

[0007] By adopting the above technical solution, the high-transparency modified polyamide masterbatch is used to simultaneously enhance the outer and middle layers. While maintaining the original high transparency and high heat shrinkage rate of the POF film, its overall puncture resistance is significantly improved, overcoming the defect of traditional POF film being easily damaged when packaging sharp items.

[0008] Optionally, the puncture-resistant POF membrane outer layer comprises the following components in parts by weight: 75-95 parts polyethylene and 5-25 parts high-transparency modified polyamide masterbatch.

[0009] Optionally, the puncture-resistant POF film middle layer contains the following components in parts by weight: 85-98 parts of polypropylene and 2-15 parts of high-transparency modified polyamide masterbatch.

[0010] By adopting the above technical solution and controlling the addition ratio of modified polyamide masterbatch in the outer and middle layers, it is possible to achieve excellent puncture strength while ensuring that the optical properties and heat shrinkage properties of the film do not decrease significantly, thus balancing protection and packaging display effects.

[0011] Optionally, the high-transparency modified polyamide masterbatch contains the following components in parts by weight: 100 parts of copolynylon matrix; 2-5 parts of organomodified montmorillonite; 0.3-0.8 parts of nucleating agent; and 5-10 parts of reactive compatibilizer.

[0012] Optionally, the reactive compatibilizer is an epoxy-anhydride bifunctional polyolefin.

[0013] Optionally, the epoxy-anhydride bifunctional polyolefin comprises the following components in parts by weight: 80-120 parts of low-density polyethylene, 1-5 parts of glycidyl methyl acrylate, 1-2 parts of maleic anhydride, 0.1-0.2 parts of dicumyl peroxide, 0.05-0.2 parts of antioxidant 1010, and 10-30 parts of acetone.

[0014] By adopting the above technical solution, the reactive compatibilizer can form a chemical bridge at the interface between polyamide and polyolefin, significantly improving the compatibility between the two phases, thereby improving the mechanical properties while maintaining the high transparency of the material; the nano-dispersion of organic montmorillonite further endows the masterbatch with a synergistic effect of reinforcement, toughening and barrier.

[0015] Optionally, the outer polyethylene layer is metallocene linear low-density polyethylene; the inner polyethylene layer is ethylene-vinyl acetate copolymer.

[0016] Optionally, the middle layer of polypropylene is homopolymer polypropylene or copolymer polypropylene.

[0017] Optionally, the thickness ratio of the outer layer, middle layer and inner layer is (0.8-1.2):(1.5-2.5):1.

[0018] By adopting the above technical solution, metallocene polyethylene endows the outer layer with good mechanical and optical properties, while the EVA inner layer provides excellent heat-sealing properties; the reasonable thickness ratio makes the functions of each layer coordinated, achieving a balance between stiffness, protection and heat-sealing reliability.

[0019] Secondly, the puncture-resistant POF membrane provided in this application, as described in the first aspect, is prepared by the following method: The outer layer raw material, middle layer raw material and inner layer raw material are melted and plasticized by three extruders to obtain a melt; The plasticized three-layer melt is fed into a three-layer co-extrusion die for co-extrusion blow molding to form a film bubble; The membrane bubble is inflated, cooled and shaped, corona treated and wound up to obtain the puncture-resistant POF membrane.

[0020] By adopting the above technical solution, the preparation method has good process compatibility, can be implemented without changing the existing POF production equipment, is suitable for large-scale production, and the resulting film has uniform and stable properties.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. By synergistically adding high-transparency modified polyamide masterbatch to the outer and middle layers, the puncture strength of POF film is significantly improved, making it suitable for packaging sharp or fragile items and broadening its application range; 2. While achieving high strength, the high transparency and high thermal shrinkage rate of the POF film are maintained, overcoming the technical contradiction that traditional reinforcement methods lead to a decline in optical and thermal properties; 3. By selecting specific reactive compatibilizers and optimizing the masterbatch formulation, the interfacial compatibility between polyamide and polyolefin is effectively improved, ensuring uniform dispersion of the reinforcing phase, thereby achieving a multifunctional balance of reinforcement, transparency, and heat shrinkage. Detailed Implementation

[0022] The present application will be further described in detail below with reference to preparation examples and embodiments.

[0023] The raw materials used in the preparation examples and embodiments are all commercially available products, and the specific information is as follows: Low-density polyethylene: Model LDPE2426H, effective ingredient content ≥99%; Glycidyl methacrylate (GMA): Supplier: Mitsubishi, CAS No. 106-91-2, purity ≥98%; Maleic anhydride: purity ≥99.5%, CAS number 108-31-6; Dicumyl peroxide: chemically pure, CAS No. 80-43-3; Antioxidant 1010: CAS No. 6683-19-8; Acetone: analytical grade, CAS No. 67-64-1; Copolymer Nylon PA66: Supplier is BASF; Organo-montmorillonite: 400 mesh, CAS No. 1302-78-9; Dibenzylsorbitol: Purity ≥99%, CAS No. 32647-67-9; Sodium organophosphate: Model NA-11, CAS No. 85209-91-2; Hindered amine light stabilizer: Supplier: BASF, Model: TINUVIN 783FDL; Metallocene linear low-density polyethylene: Part number AT6101; Homopolymer polypropylene: Supplier is Yanshan Petrochemical, item number T1701; Ethylene-vinyl acetate copolymer: The supplier is LG Korea, item number ES28005.

[0024] Preparation Example 1: Epoxy-Anhydride Bifunctional Polyolefin Low-density polyethylene (LDPE) 100 parts, glycidyl methacrylate (GMA) 3 parts, maleic anhydride (MAH) 1.5 parts, dicumyl peroxide (DCP) 0.15 parts, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 0.1 parts, acetone 20 parts Preparation method: Material A is prepared by initially mixing LDPE granules with antioxidant 1010; Dicumyl peroxide and maleic anhydride are dissolved in acetone, wherein the maleic anhydride needs to be heated at 50°C to promote dissolution, to prepare solution A; The glycidyl methacrylate monomer needs to be fed separately, namely monomer B; Set the temperature of each section of the twin-screw extruder as follows: Zone 1 is 120℃, Zone 2 is 160℃, Zone 3 is 180℃, Zone 4 is 185℃, Zone 5 is 190℃, and Zone 6 and the die head are 180℃. The premixed material A is added from the main feed port and melted and plasticized in zones one and two. Solution A is injected into the melt at the end of zone two and monomer B is injected in the middle of zone three. After passing through zones three and four, the vacuum evaporation port is opened in zone five to extract unreacted GMA, MAH monomers, acetone and other by-products. The evaporated melt is then extruded into strips. The extruded melt strip is cooled and solidified by a cooling medium, and then cut to obtain granular products. After drying, epoxy-anhydride bifunctional polyolefins are obtained for later use.

[0025] Preparation Example 2: High Transparency Modified Polyamide Masterbatch 100 parts of copolynylon PA66, 3 parts of organomontmorillonite (CAS 1302-78-9), 0.3 parts of dibenzyl sorbitol, 0.1 parts of organophosphate sodium salt, 8 parts of epoxy-anhydride bifunctional polyolefin obtained in Preparation Example 1, and 0.2 parts of hindered amine light stabilizer.

[0026] Preparation method: The copolymerized nylon PA66 and the organo-modified montmorillonite were dried. Organized montmorillonite was premixed with dibenzyl sorbitol, sodium organophosphate, and hindered amine light stabilizer for 5 minutes to obtain premix B; The temperatures of each section of the twin-screw extruder are set as follows: Zone 1 200℃, Zone 2 230℃, Zone 3 245℃, Zone 4 250℃, Zone 5 245℃, and the die head 240℃. Dry copolymer nylon granules are added from the main feed port. After the nylon matrix melts in the three zones, premix B is added evenly in the side feeder. At the same time, the ultrasonic auxiliary system is activated to break up the nanoparticle agglomerates, promoting the peeling and uniform dispersion of premix B in the nylon melt. In the preparation of the epoxy-anhydride bifunctional polyolefin obtained in Example 1, the molten state was injected in the fourth zone. The fourth zone screw is a high-shear kneading block, which allows the epoxy and anhydride groups on the compatibilizer molecular chain to react in situ with the terminal amino and terminal carboxyl groups of the nylon molecular chain under high temperature and high shear mixing conditions, forming chemical bonds. In zone five, the vacuum devolatilization port is opened to extract residual monomers and small molecule volatile substances. After homogenization, the melt is extruded through a porous die. The extruded strips are cooled, solidified, and then pelletized. The resulting masterbatch is dried and ready for use.

[0027] Example 1

[0028] Outer layer: 85 parts of metallocene linear low-density polyethylene (mLLDPE) + 15 parts of high-transparency modified polyamide masterbatch obtained from Preparation Example 2; Middle layer: 90 parts homopolymer polypropylene + 10 parts high-transparency modified polyamide masterbatch obtained from Preparation Example 2; Inner layer: 100 parts of ethylene-vinyl acetate copolymer.

[0029] Preparation method: 1. After drying each of the above-mentioned raw materials, they are fed into the three extruders corresponding to the three-layer co-extrusion blown film unit; 2. Control the temperature of each extruder and die, including: Outer extruder: Zone 1 170℃, Zone 2 185℃, Zone 3 200℃, Flange 205℃, Connector 210℃; Intermediate extruder: Zone 1 180℃, Zone 2 195℃, Zone 3 205℃, Flange 210℃, Connector 215℃; Inner extruder: Zone 1 160℃, Zone 2 175℃, Zone 3 190℃, Flange 195℃, Connector 195℃; Co-extrusion die head: adopts a spiral mandrel type three-layer co-extrusion die head, and the temperature is controlled within the range of 200-210℃; Under the action of three extruders, the raw materials of each layer are melted, plasticized, and metered, and then fed into the three-layer co-extrusion die. The melt is extruded from the die to form a barrel-shaped bubble, and compressed air is immediately injected into the bubble to inflate it, with the inflation ratio controlled at 3.8; A chiller unit was used to cool the membrane bubble, and the formed membrane bubble was subjected to corona treatment. Then, it was drawn and wound to obtain a POF heat shrink film with a thickness of 20μm, in which the thickness ratio of the outer layer, middle layer and inner layer is approximately 1:2:1.

[0030] Example 2

[0031] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer and the middle layer is adjusted. The outer layer contains 92 parts of metallocene linear low-density polyethylene (mLLDPE) and 8 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 96 parts of copolymer polypropylene and 4 parts of the high-transparency modified polyamide masterbatch obtained in Example 2.

[0032] Example 3

[0033] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer and the middle layer is adjusted. The outer layer contains 75 parts of metallocene linear low-density polyethylene (mLLDPE) and 25 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 85 parts of homopolymer polypropylene and 15 parts of the high-transparency modified polyamide masterbatch obtained in Example 2.

[0034] Example 4

[0035] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer and the middle layer is adjusted. The outer layer contains 95 parts of metallocene linear low-density polyethylene (mLLDPE) and 5 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 98 parts of homopolymer polypropylene and 2 parts of the high-transparency modified polyamide masterbatch obtained in Example 2.

[0036] Example 5

[0037] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer and the middle layer is adjusted. The outer layer contains 80 parts of metallocene linear low-density polyethylene (mLLDPE) and 20 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 87 parts of homopolymer polypropylene and 13 parts of the high-transparency modified polyamide masterbatch obtained in Example 2.

[0038] Example 6

[0039] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer and the middle layer is adjusted. The outer layer contains 75 parts of metallocene linear low-density polyethylene (mLLDPE) and 25 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 85 parts of homopolymer polypropylene and 15 parts of the high-transparency modified polyamide masterbatch obtained in Example 2.

[0040] Example 7

[0041] The difference between this embodiment and Example 1 is that the raw material ratio of the outer layer is adjusted. The outer layer contains 85 parts of metallocene linear low-density polyethylene (mLLDPE) and 15 parts of the high-transparency modified polyamide masterbatch obtained in Example 2; the middle layer contains 100 parts of homopolymer polypropylene; and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0042] Example 8

[0043] The difference between this embodiment and Example 1 is that the raw material ratio of the middle layer is adjusted. The outer layer contains 100 parts of metallocene linear low-density polyethylene (mLLDPE); the middle layer contains 90 parts of homopolymer polypropylene and 10 parts of the high-transparency modified polyamide masterbatch obtained in Preparation Example 2; and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0044] Comparative Example 1 The difference between this comparative example and Example 1 is that the raw material ratios of the outer and middle layers were adjusted. The outer layer contains 100 parts of metallocene linear low-density polyethylene (mLLDPE); the middle layer contains 100 parts of homopolymer polypropylene; and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw material ratios of the outer and middle layers have been adjusted. The outer layer contains 85 parts of metallocene linear low-density polyethylene (mLLDPE) and 15 parts of copolymer nylon PA66 (i.e., unmodified polyamide masterbatch); the middle layer contains 100 parts of homopolymer polypropylene; and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0046] Comparative Example 3 The difference between this comparative example and Example 1 is that the raw material ratios of the outer and middle layers were adjusted. The outer layer contains 100 parts of metallocene linear low-density polyethylene (mLLDPE); the middle layer contains 90 parts of homopolymer polypropylene and 10 parts of copolymer nylon PA66 (i.e., unmodified polyamide masterbatch); and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0047] Comparative Example 4 The difference between this comparative example and Example 1 is that the raw material ratios of the outer and middle layers were adjusted. The outer layer contains 85 parts of metallocene linear low-density polyethylene (mLLDPE) and 15 parts of copolynylon PA66 (i.e., unmodified polyamide masterbatch); the middle layer contains 90 parts of homopolymer polypropylene and 10 parts of copolynylon PA66 (i.e., unmodified polyamide masterbatch); and the inner layer contains 100 parts of ethylene-vinyl acetate copolymer.

[0048] Performance testing Test methods Puncture resistance: The test standard is based on 37841-2019 "Test method for puncture resistance of plastic films and sheets"; Light transmittance: The test standard refers to ASTM D1003. The test procedure measures the ratio of the light flux transmitted through the sample to the incident light flux. Haze: The testing standard is based on ASTM D1003. The test method is to measure the ratio of the backscattered light flux through the sample to the total transmitted light flux. Heat shrinkage rate: The testing standard is based on ASTM D1204; The test results are shown in Table 1.

[0049] Table 1. Test results data for each embodiment and comparative example.

[0050] In Example 1, by synergistically introducing the high-transparency modified polyamide particles into the outer and middle layers, the resulting film maintains excellent light transmittance and thermal shrinkage properties while significantly improving puncture resistance, indicating that this approach can enhance mechanical properties while maintaining the key optical and thermal properties of the material.

[0051] In Example 2, even with a relatively low addition amount of the modified particles, the film still exhibited significantly higher puncture resistance than the conventional structure. This demonstrates that even at lower addition ratios, the modified particles can still effectively interact with the polyolefin matrix, providing a viable pathway for cost-sensitive applications.

[0052] In Example 3, further increasing the amount of the modified particles resulted in a film exhibiting even higher puncture resistance. Notably, its light transmittance did not decrease significantly, indicating that the modified particles still possess good optical compatibility at high addition levels, overcoming the transparency degradation problem often associated with highly filled systems.

[0053] In Example 4, the amount of the modified particles added was further reduced to a trace level, and the film still exhibited a higher puncture strength than the traditional structure, proving that the functional masterbatch has a high enhancement efficiency and can achieve effective performance improvement at low addition levels.

[0054] In Example 5, by adjusting the ratio of the modified particles in the outer and middle layers, the film can achieve outstanding puncture resistance while maintaining the thermal shrinkage rate to the greatest extent, demonstrating that a good balance between mechanical properties and thermal function can be achieved through ratio optimization.

[0055] The results of Example 6 and Example 3 corroborate each other, jointly defining the performance boundary of the modified particles at high addition levels, indicating that within this addition range, the film can simultaneously possess high puncture resistance, acceptable transparency, and qualified thermal shrinkage.

[0056] Example 7 investigated the effect when the modified particles were distributed only in the outer layer. The results showed that the performance improvement brought by the single-layer reinforcement structure was limited, far lower than that of the two-layer synergistic system, thus highlighting the necessity of the "outer-middle layer" co-reinforcement structural design.

[0057] Example 8 further verifies the importance of the above structural design. When the middle layer is used alone as a reinforcing layer, its final performance is similar to that of reinforcing only the outer layer, neither of which can achieve the strengthening effect of the two-layer synergistic system. This proves that simultaneously introducing the modified particles into both the outer layer, which directly contacts the outside world, and the middle layer, which provides the main support, is the key to achieving the optimal comprehensive protection effect.

[0058] Comparative Example 1, serving as a reference for traditional three-layer POF membranes, exhibits lower puncture strength, reflecting the typical performance level of existing technologies.

[0059] Comparative Examples 2 and 3 show that when ordinary polyamide particles are used to modify only a single layer, not only is the reinforcing effect limited, but it also leads to a significant decrease in film transparency. This, from a comparative perspective, confirms the unique role of the "high-transparency modified polyamide particles" used in this invention in resolving the contradiction between interfacial compatibility and optical performance.

[0060] Comparative Example 4 shows that even with the simultaneous addition of ordinary polyamide particles to both the outer and middle layers, while a certain strength improvement can be achieved, it leads to a severe deterioration in transparency and a decrease in heat shrinkage performance. This contrasts sharply with the performance balance achieved in the various embodiments of the present invention, thus proving that the overall solution of "high transparency modified masterbatch-double-layer synergistic structure" provided by the present invention is an effective way to achieve a synergistic improvement in high strength, high transparency, and high heat shrinkage rate.

[0061] In summary, this invention achieves a good balance between puncture resistance, light transmittance, and thermal shrinkage in the prepared POF film by employing a specific high-transparency modified polyamide functional masterbatch and combining it with a composite structure of synergistic addition of outer and middle layers. This approach significantly improves puncture resistance while avoiding the decreased transparency and functional loss due to thermal shrinkage that are typically caused by traditional reinforcing materials, providing a new technical pathway for the preparation of high-performance POF films.

[0062] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A puncture-resistant POF membrane, characterized in that, A three-layer co-extruded structure consisting of an outer layer, a middle layer, and an inner layer: The outer layer comprises polyethylene and a high-transparency modified polyamide masterbatch; The middle layer comprises polypropylene and a high-transparency modified polyamide masterbatch; The inner layer comprises polyethylene; The high-transparency modified polyamide masterbatch includes a copolymer nylon matrix, an organo-modified montmorillonite dispersed in the copolymer nylon matrix, a nucleating agent, and a reactive compatibilizer.

2. The puncture-resistant POF membrane according to claim 1, characterized in that, The puncture-resistant POF membrane outer layer comprises the following components in parts by weight: 75-95 parts polyethylene and 5-25 parts high-transparency modified polyamide masterbatch.

3. The puncture-resistant POF membrane according to claim 1, characterized in that, The puncture-resistant POF film middle layer contains the following components in parts by weight: 85-98 parts of polypropylene and 2-15 parts of high-transparency modified polyamide masterbatch.

4. The puncture-resistant POF membrane according to claim 1, characterized in that, The high-transparency modified polyamide masterbatch comprises the following components in parts by weight: 100 parts of copolymerized nylon matrix; 2-5 parts of organomodified montmorillonite; 0.3-0.8 parts of nucleating agent; 5-10 parts of reactive compatibilizer.

5. The puncture-resistant POF membrane according to claim 4, characterized in that, The reactive compatibilizer is an epoxy-anhydride bifunctional polyolefin.

6. The puncture-resistant POF membrane according to claim 5, characterized in that, The epoxy-anhydride bifunctional polyolefin comprises the following components in parts by weight: Low-density polyethylene 80-120 parts, glycidyl methyl acrylate 1-5 parts, maleic anhydride 1-2 parts, dicumyl peroxide 0.1-0.2 parts, antioxidant 1010 0.05-0.2 parts, acetone 10-30 parts.

7. The puncture-resistant POF membrane according to claim 1, characterized in that, The outer layer of polyethylene is metallocene linear low-density polyethylene; the inner layer of polyethylene is ethylene-vinyl acetate copolymer.

8. The puncture-resistant POF membrane according to claim 1, characterized in that, The polypropylene in the middle layer is either homopolymer polypropylene or copolymer polypropylene.

9. The puncture-resistant POF membrane according to claim 1, characterized in that, The thickness ratio of the outer layer, middle layer and inner layer is (0.8-1.2):(1.5-2.5):

1.

10. A method for preparing a puncture-resistant POF membrane as described in any one of claims 1-9, characterized in that, Includes the following steps: The outer layer raw material, middle layer raw material and inner layer raw material are melted and plasticized by three extruders to obtain a melt; The plasticized three-layer melt is fed into a three-layer co-extrusion die for co-extrusion blow molding to form a film bubble; The membrane bubble is inflated, cooled and shaped, corona treated and wound up to obtain the puncture-resistant POF membrane.

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