Multi-element synergistic super-hydrophobic breathable polyolefin film and preparation method thereof

Abstract

The invention discloses a multi-element synergistic super-hydrophobic breathable polyolefin film and a preparation method thereof, the surface layer is covered with polyolefin wax, the interior is lubricated by fluorinated ethylene propylene copolymer, and polyolefin processing defects are filled with porous hydrophobic micromolecules in an adsorption manner, the film material provided by the invention not only has ultrahigh water resistance, but also has relatively excellent gas permeability, and the film material is suitable for large-scale production. Meanwhile, the excellent mechanical property is also realized. According to the application method, mature equipment in the market can be fully used, no additional equipment needs to be purchased, production conversion is easy, and high economic value is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of polymer membrane materials, and particularly relates to a multi-element synergistic superhydrophobic and breathable polyolefin membrane and a preparation method thereof. Background Art

[0002] Chinese Patent ZL 201810176630.2 discloses a superhydrophobic membrane, a semiconductor packaging structure with the superhydrophobic membrane and a packaging method thereof. The superhydrophobic membrane has a porous micro-nano structure, and the basic composition of the superhydrophobic membrane is rubrene derivatives with hydrophobic groups; the semiconductor packaging structure includes a substrate, electronic functional devices disposed on the substrate, a first sealing film disposed on the side of the electronic functional devices away from the substrate, and the superhydrophobic membrane as described above; the semiconductor packaging method includes preparing and forming a first sealing film and the superhydrophobic membrane as described above on the side of the electronic functional devices away from the substrate. The superhydrophobic effect of this technology is achieved by combining hydrophobic groups with the porous micro-nano structure of the superhydrophobic membrane itself, effectively reducing water vapor penetration; the semiconductor packaging structure using the aforementioned superhydrophobic membrane can effectively improve the waterproof performance, and the process is more concise. However, the air permeability and mechanical properties are poor, and the actual product performance is poor, unable to bring greater economic benefits.

[0003] Chinese Patent ZL 202123264499.1 discloses a PTEF hydrophobic and breathable membrane, which includes a hydrophobic and breathable membrane and a single-membrane storage mechanism. The hydrophobic and breathable membrane is composed of a base film, inner film strip A, inner film strip B and a coating film. The surface of the base film is compounded with inner film strip A and inner film strip B, and the surface of the base film, inner film strip A and inner film strip B is compounded with a coating film. The hydrophobic and breathable membrane is wound and stored in the single-membrane storage mechanism. By improving the hydrophobic and breathable membrane, an inner-core composite film body is formed by compounding inner film strip A and inner film strip B between the base film and the coating film. Furthermore, the hydrophobic and breathable membrane of this composite film body realizes the improvement of the toughness and strength of the membrane body by means of an inner strengthening structure, achieving the multi-layer optimization and toughness and strength optimization of the hydrophobic and breathable membrane. However, the preparation process is complex and time-consuming, which is not conducive to continuous production.

[0004] Chinese Patent CN115058827A discloses a novel hydrophobic and breathable membrane, an air inlet structure of an infusion set, and an infusion set. The hydrophobic and breathable membrane includes a first support layer, an intermediate membrane, and a second support layer. The intermediate membrane is located between the first support layer and the second support layer, and the intermediate membrane is connected to the first support layer and the second support layer respectively. The outer surface of the first support layer is a hydrophobic and breathable surface. The intermediate membrane is a PTFE membrane, the thickness of the intermediate membrane is 8 - 20 microns, and the overall thickness of the hydrophobic and breathable membrane is less than or equal to 0.3 mm. This membrane has antibacterial properties, good air permeability, and a relatively high dust capacity. Moreover, since the PTFE membrane is supported by the support layers on both sides, it is not easily deformed. However, its hydrophobicity still needs to be further improved.

[0005] Chinese Patent ZL 202311284705.6 discloses a polytetrafluoroethylene superhydrophobic and breathable membrane, its preparation method and application. The preparation method includes the following steps: (1) Mixing polytetrafluoroethylene dispersion resin and auxiliary oil, curing, pre-pressing, extruding, and calendering to obtain a polytetrafluoroethylene base membrane; (2) Heating the polytetrafluoroethylene base membrane obtained in step (1) to remove the auxiliary oil, coating a coating material, pre-drying and shaping, stretching, and heat-setting to obtain the polytetrafluoroethylene superhydrophobic and breathable membrane; the coating material includes a fluororesin, and the fluororesin includes fluororesin particles and / or fluororesin emulsion. The polytetrafluoroethylene superhydrophobic and breathable membrane prepared by the preparation method provided by the present invention has the characteristics of superhydrophobic surface, good air permeability, and simple preparation process. However, too many additives are added, and the materials are not easily obtained.

[0006] In summary, developing a polyolefin film with a novel structure and both superhydrophobicity and breathability has become an urgent problem to be solved in the industry development. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a multi-element synergistic superhydrophobic and breathable polyolefin film and its preparation method. The multi-element synergistic superhydrophobic and breathable polyolefin film prepared by the preparation method of the present invention has the characteristics of superhydrophobic surface, good air permeability, and simple preparation process.

[0008] The present invention proposes a multi-element synergistic superhydrophobic and breathable polyolefin film. The surface of this superhydrophobic and breathable membrane is covered with polyolefin wax, and the inside is internally lubricated with ethylene-propylene fluoride copolymer. Porous hydrophobic small molecules are adsorbed and filled in the processing defects of polyolefin.

[0009] Furthermore, for the multi-element synergistic superhydrophobic and breathable polyolefin film, by weight, the components and their contents are as follows: Polyolefin resin 80 - 90 parts; Ethylene-propylene fluoride copolymer 5 - 15 parts; Polyolefin wax 0.5 - 3 parts; 0.5 - 3 parts of porous hydrophobic small molecules; 0.05 - 0.5 parts of cross - linker.

[0010] As a further solution of the present invention, the fluorinated ethylene propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene, and the content of hexafluoropropylene is 14% - 25%.

[0011] As a further solution of the present invention, the porous hydrophobic small molecule is silica with a specific structure, the specific surface area is 90 - 130 m 2 / g, the pH value is 3.6 - 4.4, and the laser particle size is 7 - 40 nm.

[0012] As a further solution of the present invention, for the multi - element synergistic super - hydrophobic and breathable polyolefin film, the water permeability is 1.20 - 0.80 g / (m 2 ·24 h); the carbon dioxide permeation amount is 28000 - 35000 cm 3 / (m 2 ·24 h·0.1 MPa); the tensile strength is 15 - 25 MPa, and the elongation at break is 1100 - 1300%. The film material of the present invention not only has excellent water - blocking performance, but also has excellent gas - permeation performance. The film material of the present invention also has excellent mechanical properties. A preparation method of a multi - element synergistic super - hydrophobic and breathable polyolefin film. The super - hydrophobic and breathable polyolefin film is prepared according to the following steps: 1) Add the weighed polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, porous hydrophobic small molecules and cross - linker into a twin - screw extruder, carry out melt blending at 240 - 300 °C, cool through water, air - dry and pelletize with a pelletizer to obtain blended pellets.

[0013] 2) Add the above - mentioned blended pellets into a film - drawing machine to blow - mold the film to obtain the film of the present invention. The temperature of the film - drawing machine is 240 - 300 °C, and the draw ratio is 4.0 - 6.0. The application method of the present invention can make full use of mature market equipment, without the need to purchase additional equipment, and the production conversion is easy, with high economic value.

[0014] As a further solution of the present invention, the cross - linker is dicumyl peroxide.

[0015] In the present invention, ethylene tetrafluoroethylene copolymer, hydrophobic silica, and polyolefin wax endow the multi-element synergistic superhydrophobic and breathable polyolefin film with hydrophobic and breathable properties through multi-scale synergistic effects. The ethylene tetrafluoroethylene copolymer forms "lubricating microdomains" during melt processing due to its extremely low coefficient of friction, dispersing between the polyolefin molecular chains to reduce the melt viscosity. The rich -CF2 and -CF3 groups are evenly distributed in the amorphous region and on the film surface through low surface energy, blocking water vapor penetration; the polyolefin wax dynamically stratifies during processing due to its low viscosity, constructing a superhydrophobic micro-structure on the film surface to further enhance hydrophobicity; while the hydrophobic silica selectively fills the amorphous region of the polyolefin, and its nanoparticles form a size sieving network, allowing small molecule gases to diffuse through the defect channels, but blocking water vapor molecules through polar repulsion and steric hindrance. The three optimize synergistically from three dimensions: processing lubrication, surface micro-structure regulation, and internal barrier channel design, ultimately achieving an efficient balance of high hydrophobicity, breathability, and moisture barrier property of the polyolefin film.

[0016] The present invention has the following beneficial effects: The present invention provides a multi-element synergistic superhydrophobic and breathable polyolefin film and its preparation method, which are prepared by melt blending polyolefin, ethylene tetrafluoroethylene copolymer, polyolefin wax, porous hydrophobic small molecules, and cross-linking agent in a twin-screw extruder and then drawing the film. The surface layer of the superhydrophobic and breathable film is covered with polyolefin wax, and the internal lubrication is achieved by ethylene tetrafluoroethylene copolymer, and the porous hydrophobic small molecules are adsorbed and filled in the processing defects of the polyolefin. The film material of the present invention not only has ultra-high water resistance, but also has excellent gas permeability, and at the same time has excellent mechanical properties. The application method of the present invention can make full use of the mature equipment in the market, without the need to purchase additional equipment, and the production conversion is easy, with high economic value.

[0017] To more clearly illustrate the structural features and functions of the present invention, the following will combine the drawings with specific embodiments to elaborate on the present invention in detail. Description of the Drawings

[0018] Figure 1 It is the Fourier transform infrared spectrum diagram of Example 1 of the present invention.

[0019] Figure 2 It is the laser confocal microscope diagram of Example 1 of the present invention.

[0020] Figure 3 It is the contact angle diagram of Example 1 of the present invention.

[0021] Figure 4 It is the stress-strain curve diagram of Example 1 of the present invention. Detailed Embodiments

[0022] The following will further illustrate the present invention in combination with the drawings and relevant knowledge, and describe it clearly and completely. Obviously, the described applications are only a part of the embodiments of the present invention, rather than all the embodiments.

[0023] The object of the present invention is to provide a multi-element synergistic superhydrophobic and breathable polyolefin film and a preparation method thereof. The multi-element synergistic superhydrophobic and breathable polyolefin film prepared by the preparation method of the present invention has the characteristics of superhydrophobic surface, good breathability and simple preparation process.

[0024] A multi-element synergistic superhydrophobic and breathable polyolefin film, with a water permeability of 1.20 - 0.80 g / (m 2 ·24 h); a carbon dioxide permeation amount of 28,000 - 35,000 cm 3 / (m 2 ·24 h·0.1 MPa); a tensile strength of 15 - 25 MPa and an elongation at break of 1100 - 1300%.

[0025] A multi-element synergistic superhydrophobic and breathable polyolefin film, by weight, the components and their contents are as follows: Polyolefin resin 80 - 90 parts; Fluorinated ethylene propylene copolymer 5 - 15 parts; Polyolefin wax 0.5 - 3 parts; Porous hydrophobic small molecule 0.5 - 3 parts; Crosslinking agent 0.05 - 0.5 parts.

[0026] To achieve this purpose, the present invention adopts the following technical solutions: A multi-element synergistic superhydrophobic and breathable polyolefin film, the surface layer of the superhydrophobic and breathable film is covered with polyolefin wax, and the inside is internally lubricated with fluorinated ethylene propylene copolymer, and the polyolefin processing defects are internally adsorbed and filled with porous hydrophobic small molecules.

[0027] Provide a preparation method of a multi-element synergistic superhydrophobic and breathable polyolefin film as described above. The superhydrophobic and breathable polyolefin film is prepared according to the following steps: 1) Add the weighed polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, porous hydrophobic small molecule and crosslinking agent into a twin-screw extruder, carry out melt blending at 240 - 300 °C, cool through water, air dry and pelletize with a pelletizer to obtain blended pellets.

[0028] 2) Add the above blended pellets into a film blowing machine to blow the film to obtain the product of the present invention. The temperature of the film blowing machine is 240 - 300 °C, and the draw ratio is 4.0 - 6.0.

[0029] In the present invention, the fluorinated ethylene propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene, and the content of hexafluoropropylene is 14 - 25%. The porous hydrophobic small molecule is silica with a specific structure, the specific surface area is 90 - 130 m 2 / g, the pH value is 3.6 - 4.4, and the laser particle size is 7 - 40 nm. The crosslinking agent is dicumyl peroxide.

[0030] In the present invention, the fluorinated ethylene propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene (the content of hexafluoropropylene is 14% - 25%), containing -CF2 and -CF3 groups with extremely low surface energy, which are uniformly distributed on the film surface and in the amorphous region, blocking water vapor penetration; during melt processing, "lubricating microdomains" are formed, reducing the melt viscosity and improving the processing performance. Polyolefin wax, with its low viscosity characteristic, dynamically stratifies during processing, constructing a superhydrophobic micro-structure on the film surface and enhancing the surface hydrophobicity. Porous hydrophobic small molecules, silica with a specific structure (specific surface area 90 - 130 m² / g, pH 3.6 - 4.4, particle size 7 - 40 nm), selectively fill the defects in the amorphous region of polyolefin, forming a nano-scale sieving network, blocking water vapor through polar repulsion and steric hindrance, while allowing small molecule gases to pass through. Crosslinking agent, dicumyl peroxide, is used to improve the crosslinking degree of polyolefin molecular chains and enhance the mechanical properties of the film.

[0031] The internal barrier and sieving network of the present invention: the fluorinated ethylene propylene copolymer is dispersed between the polyolefin molecular chains, reducing the melt viscosity and uniformly distributing low surface energy groups, hindering water vapor penetration; the porous hydrophobic silica fills the defects in the amorphous region of polyolefin, utilizing the nano-scale pore size sieving effect (7 - 40 nm) to allow small molecule gases such as CO2 to pass through, while repelling polar water molecules through polar difference (pH 3.6 - 4.4) and steric hindrance. The mechanical properties are optimized, and the crosslinking agent (dicumyl peroxide) promotes the crosslinking of molecular chains, enhancing the tensile strength and elongation at break of the film, and balancing flexibility and durability.

[0032] In the present invention, the superhydrophobic surface (water blocking) and high gas permeability (allowing small molecule gases to pass through) are efficiently balanced, and at the same time, it has excellent mechanical properties (high strength and high toughness). Through the three-dimensional cooperation of surface micro-structure (polyolefin wax), internal lubrication and low surface energy groups (fluorinated ethylene propylene copolymer), and nano-sieving network (porous hydrophobic silica), it breaks through the performance contradiction between water blocking and gas permeability of traditional polyolefin films, uses the processing defects of polyolefin as the adsorption sites for porous hydrophobic small molecules, turns "defects" into "functional channels", and realizes the precise regulation of barrier and gas permeability.

[0033] Example 1, a multi-element synergistic superhydrophobic and breathable polyolefin film, is prepared by the following method: 1) Weigh the polyolefin (polyethylene, manufacturer: Dow Chemical, grade: 41E687), fluorinated ethylene propylene copolymer (FEP, manufacturer: Daikin Japan, grade: cn120), polyolefin wax (polyethylene wax, manufacturer: Mitsui Chemicals, grade: 07500), porous hydrophobic small molecule (SiO2, manufacturer: Celite, grade: SK-200s) and crosslinking agent (dicumyl peroxide), and mix them and add them into a twin-screw extruder. Carry out melt blending at three-zone temperatures of 240 °C, 290 °C, and 300 °C respectively, cool by passing through water, air-dry and pelletize with a pelletizer to obtain blended pellets.

[0034] 2) Add the above blended pellets into a film blowing machine to blow the film to obtain the present invention. The three-zone temperatures of the film blowing machine are 240 °C, 290 °C, and 300 °C respectively, and the draw ratio is 4.0.

[0035] Among them, based on the total mass of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax and porous hydrophobic small molecule being 100%, the mass percentage of the polyethylene is 88%, the mass percentage of the fluorinated ethylene propylene copolymer is 10%, the mass percentage of the polyethylene wax is 1%, and the mass percentage of the porous hydrophobic silica is 1%. The mass percentage of the crosslinking agent is 0.5%.

[0036] A multi-element synergistic superhydrophobic and breathable polyolefin film prepared by this method has a water permeability of 0.96 g / (m 2 ·24h); the carbon dioxide permeation amount is 38657 cm 3 / (m 2 ·24h·0.1MPa); the tensile strength is 19 MPa, and the elongation at break is 1268%.

[0037] Example 2. This example provides a multi-element synergistic superhydrophobic and breathable polyolefin film and its preparation method. The difference from Example 1 is only that in step (1), the mass ratio of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax and porous hydrophobic small molecule is different, and the others are the same as in Example 1.

[0038] Among them, based on the total mass of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax and porous hydrophobic small molecule being 100%, the mass percentage of the polyethylene is 86%, the mass percentage of the fluorinated ethylene propylene copolymer is 10%, the mass percentage of the polyethylene wax is 3%, and the mass percentage of the porous hydrophobic silica is 1%. The mass percentage of the crosslinking agent is 0.5%.

[0039] A multi-element synergistic superhydrophobic and breathable polyolefin film prepared by this method has a water permeability of 1.09 g / (m 2 ·24h); the carbon dioxide permeation amount is 31864 cm 3 / (m 2·24 h·0.1 MPa); Tensile strength is 16 MPa, and elongation at break is 1173%.

[0040] Example 3. This example provides a multi-element synergistic superhydrophobic and breathable polyolefin film and its preparation method. The difference from Example 1 is only that in step (1), the mass ratios of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, and porous hydrophobic small molecule are different, and the others are the same as in Example 1.

[0041] Among them, based on the total mass of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, and porous hydrophobic small molecule being 100%, the mass percentage of the polyethylene is 86%, the mass percentage of the fluorinated ethylene propylene copolymer is 10%, the mass percentage of the polyethylene wax is 1%, and the mass percentage of the porous hydrophobic silica is 3%. The mass percentage of the cross-linking agent is 0.5%.

[0042] A multi-element synergistic superhydrophobic and breathable polyolefin film prepared by this method has a water permeability of 1.2 g / (m 2 ·24 h); The carbon dioxide permeation amount is 35000 cm 3 / (m 2 ·24 h·0.1 MPa); Tensile strength is 15 MPa, and elongation at break is 1100%.

[0043] Example 4. This example provides a multi-element synergistic superhydrophobic and breathable polyolefin film and its preparation method. The difference from Example 1 is only that in step (1), the mass ratios of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, porous hydrophobic small molecule, and cross-linking agent are different, and the others are the same as in Example 1.

[0044] Among them, based on the total mass of polyolefin, fluorinated ethylene propylene copolymer, polyolefin wax, and porous hydrophobic small molecule being 100%, the mass percentage of the polyethylene is 89%, the mass percentage of the fluorinated ethylene propylene copolymer is 10%, the mass percentage of the polyethylene wax is 0.5%, and the mass percentage of the porous hydrophobic silica is 0.5%. The mass percentage of the cross-linking agent is 0.05%.

[0045] A multi-element synergistic superhydrophobic and breathable polyolefin film prepared by this method has a water permeability of 0.8 g / (m 2 ·24 h); The carbon dioxide permeation amount is 28000 cm 3 / (m 2 ·24 h·0.1 MPa); Tensile strength is 25 MPa, and elongation at break is 1300%.

[0046] Comparative Example 1, a preparation method of a multi-element synergistic superhydrophobic and breathable polyolefin film, the main steps of which are the same as those of Example 1, the difference is that no porous hydrophobic small molecule is added in Step 1, and finally a multi-element synergistic superhydrophobic and breathable polyolefin film is prepared, with a water permeability of 0.10 g / (m 2 ·24 h), carbon dioxide permeability of 11362 cm 3 / (m 2 ·24 h·0.1 MPa), tensile strength of 18 MPa, and elongation at break of 1219%.

[0047] Comparing with Example 1, it can be seen that its gas permeability has decreased significantly. The main reason is that the amorphous region of polyolefin cannot form defect channels that allow small molecule gases to diffuse through Comparative Example 2, a preparation method of a multi-element synergistic superhydrophobic and breathable polyolefin film, the main steps of which are the same as those of Example 1, the difference is that no polyolefin wax is added in Step 1, and finally a multi-element synergistic superhydrophobic and breathable polyolefin film is prepared, with a water permeability of 1.16 g / (m 2 ·24 h), carbon dioxide permeability of 37621 cm 3 / (m 2 ·24 h·0.1 MPa), tensile strength of 4 MPa, and elongation at break of 300%.

[0048] Comparing with Example 1, it can be seen that its tensile strength and elongation at break have decreased significantly. The main reason is that the lack of addition of polyolefin wax makes the blend system lack a compatibilizer

[0049] Comparative Example 3, a preparation method of a multi-element synergistic superhydrophobic and breathable polyolefin film, the main steps of which are the same as those of Example 1, the difference is that no ethylene tetrafluoroethylene copolymer is added in Step 1, and finally a multi-element synergistic superhydrophobic and breathable polyolefin film is prepared, with a water permeability of 2.88 g / (m 2 ·24 h), carbon dioxide permeability of 29483 cm 3 / (m 2 ·24 h·0.1 MPa), tensile strength of 18 MPa, and elongation at break of 1255%.

[0050] Comparing with Example 1, it can be seen that its water permeability has decreased significantly. The main reason is that the lack of -CF2 and -CF3 groups it contains are evenly distributed in the amorphous region and the film surface through low surface energy, blocking the penetration of water vapor

[0051] The technical principle of the present invention has been described above in conjunction with specific embodiments, which are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. Any technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. Those skilled in the art can readily conceive of other specific embodiments of the present invention without creative efforts, and these embodiments will all fall within the protection scope of the present invention.

Claims

1. A multi-element synergistic superhydrophobic and breathable polyolefin film, characterized in that, The surface is covered with polyolefin wax, and the inside uses ethylene tetrafluoride propylene copolymer for internal lubrication. Porous hydrophobic small molecules are adsorbed and filled in the processing defects of polyolefin.

2. The multi-element synergistic superhydrophobic and breathable polyolefin film according to claim 1, characterized in that, Water permeability: 1.20 - 0.80 g / (m 2 ·24 h); Carbon dioxide permeability: 28000 - 35000 cm 3 / (m 2 ·24 h·0.1 MPa); Tensile strength: 15 - 25 MPa, Elongation at break: 1100 - 1300%.

3. The multi-element synergistic superhydrophobic and breathable polyolefin film according to claim 2, characterized in that, The ethylene tetrafluoride propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene, and the content of hexafluoropropylene is 14% - 25%.

4. The multi-element synergistic superhydrophobic and breathable polyolefin film according to claim 3, characterized in that, The porous hydrophobic small molecule is silica with a specific structure, having a specific surface area of 90 - 130 m 2 / g, a pH value of 3.6 - 4.4, and a laser particle size of 7 - 40 nm.

5. The multi-element synergistic superhydrophobic and breathable polyolefin film according to claim 4, characterized in that By weight, the components and their contents are as follows: 80 - 90 parts of polyolefin resin; 5 - 15 parts of ethylene tetrafluoride propylene copolymer; 0.5 - 3 parts of polyolefin wax; 0.5 - 3 parts of porous hydrophobic small molecules; 0.05 - 0.5 parts of crosslinking agent.

6. A method for preparing a multi-element synergistic superhydrophobic and breathable polyolefin film as described in claim 1, characterized in that, It includes the following steps: Add the weighed polyolefin, ethylene tetrafluoride propylene copolymer, polyolefin wax, porous hydrophobic small molecules and crosslinking agent into a twin-screw extruder, carry out melt blending at 240 - 300 °C, cool through water, air dry and pelletize with a pelletizer to obtain blended pellets; Add the above blended pellets into a film blowing machine to blow the film. The temperature of the film blowing machine is 240 - 300 °C, and the draw ratio is 4.0 - 6.

0.

7. The preparation method of a multi-element synergistic superhydrophobic and breathable polyolefin film according to claim 6, wherein The crosslinking agent is dicumyl peroxide.

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