High-oxygen-barrier and moisture-barrier PE film and process

Abstract

The application relates to the field of high polymer materials, and particularly discloses a high-oxygen-resistance and high-moisture-resistance PE film and a process. The high-oxygen-resistance and high-moisture-resistance PE film comprises a corona layer, a barrier layer and a heat-sealing layer which are sequentially connected, the barrier layer comprises the following raw materials in parts by weight: 90-95 parts of polyethylene and 5-10 parts of polyvinylidene chloride, and the heat-sealing layer is made of polyethylene material; in addition, the preparation method has the advantages that the oxygen-resistance and moisture-resistance performance of the polyethylene single film is improved, and the printing requirement is met.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and more specifically, to a high oxygen and moisture barrier PE film and its process. Background Technology

[0002] In the field of packaging materials, film materials have always been an important component. As people's requirements for product quality and shelf life continue to increase, higher standards are being set for the performance of packaging films. Especially in the food and pharmaceutical industries, packaging films not only need to possess good physical properties, such as strength and flexibility, but also excellent oxygen and moisture barrier properties to prevent products from deteriorating or being damaged by oxygen and moisture, thereby extending product shelf life and ensuring product quality.

[0003] Currently, there are several conventional methods for preparing films with oxygen and moisture barrier properties. One common method is to use a single polyethylene material to make the film, utilizing the inherent properties of polyethylene to provide a certain barrier effect. Another approach is to use multilayer composite films, employing different materials in different layers. The barrier properties of the film are enhanced through the synergistic effect of the materials in each layer; for example, combining a material with certain barrier properties with polyethylene. Additionally, coatings are sometimes applied to the film surface to improve its oxygen and moisture barrier capabilities; these coating materials typically possess good barrier properties.

[0004] However, these existing technologies have certain drawbacks. Films made from a single polyethylene material have limited oxygen and moisture barrier properties, making it difficult to meet the packaging requirements of products with high barrier performance. While multilayer composite films improve barrier performance to some extent, the composite process is complex and costly, and the bonding strength between the layers may not be ideal, leading to delamination and other problems. Furthermore, in terms of packaging appearance, their transparency is poor, failing to meet printing and aesthetic requirements. Summary of the Invention

[0005] In order to improve the oxygen and moisture barrier properties of polyethylene monolayer while meeting printing requirements, this application provides a high oxygen and moisture barrier PE film and process.

[0006] In the first aspect, this application provides a high oxygen and moisture barrier PE film, which adopts the following technical solution:

[0007] A high oxygen and moisture barrier PE film includes a corona layer, a barrier layer and a heat-sealing layer connected in sequence. The barrier layer comprises the following raw materials in parts by weight: 90-95 parts polyethylene and 5-10 parts polyvinylidene chloride. The heat-sealing layer is made of polyethylene.

[0008] By adopting the above technical solution, the high oxygen and moisture barrier PE film adopts a structural design of a corona layer, a barrier layer and a heat-sealing layer connected in sequence. The corona layer can improve the adhesion of the film surface and facilitate subsequent processing. The barrier layer includes polyethylene and polyvinylidene chloride. Polyethylene has good flexibility and processing performance, while polyvinylidene chloride has excellent oxygen and moisture barrier properties. The combination of the two enables the barrier layer to effectively block the permeation of oxygen and water vapor. The heat-sealing layer is made of polyethylene material. Polyethylene has good heat-sealing performance and can easily achieve heat sealing between films to form a complete packaging structure, thereby ensuring that the entire PE film has high oxygen and moisture barrier performance.

[0009] Preferably, the high oxygen and moisture barrier PE film further includes a modified polyvinyl alcohol coating, which comprises the following raw materials in parts by weight: 15-20 parts of polyvinyl alcohol emulsion and 0.9-1.1 parts of water-resistant modifier.

[0010] By adopting the above technical solution, a modified polyvinyl alcohol coating is brushed onto the surface of a high oxygen and moisture barrier PE film. The polyvinyl alcohol emulsion itself has certain film-forming and barrier properties, and can form a continuous film layer on the film surface, which has a certain barrier effect on oxygen and water vapor. The addition of water-resistant modifier can further improve the water resistance of the coating. The water-resistant modifier can prevent water vapor from eroding the coating and prevent the coating from swelling, dissolving or degrading due to water absorption, thereby maintaining the integrity and stability of the coating and ensuring its barrier effect on oxygen and water vapor. At the same time, the water-resistant modifier can also effectively improve the water resistance of the modified polyvinyl alcohol coating, making the coating less prone to swelling or dissolving due to excessive humidity, which is conducive to maintaining the strength and integrity of the modified polyvinyl alcohol coating.

[0011] Preferably, the water-resistant modifier is modified silica aerogel, and the preparation method of the modified silica aerogel includes the following steps: adding tetraethyl orthosilicate to an ethanol solution, adjusting the pH to 4-5, hydrolyzing, adding an ethanol solution of ammonia to adjust the pH to 7-8, adding nano-silica, ultrasonically dispersing evenly, allowing it to stand to form a wet gel, and after aging and hydrophobic treatment, supercritical drying is performed to obtain the modified silica aerogel.

[0012] By adopting the above technical solution, tetraethyl orthosilicate can undergo hydrolysis and polycondensation under alkaline conditions. The addition of nano-silica can form a rigid network, which is beneficial to the formation of wet gel and improves the strength of aerogel. Water treatment can endow the wet gel with hydrophobicity, making it have better water resistance in subsequent use. The complex pores of aerogel can effectively block water vapor and oxygen, thereby improving the oxygen and moisture barrier performance of the membrane material.

[0013] Preferably, the amount of nano-silica added is 3.65-4.12 wt% of tetraethyl orthosilicate.

[0014] By adopting the above technical solution and controlling the amount of nano-silica added, the nano-silica is uniformly dispersed in the system during ultrasonic dispersion, which can effectively adjust the microstructure of the wet gel, making it form a more uniform and dense network structure, which is beneficial to improving the stability of the wet gel and giving the prepared modified silica aerogel better performance.

[0015] Preferably, the hydrophobic treatment of the modified silica aerogel includes the following steps: placing the aged wet gel in hexamethyldisilazane, allowing it to stand for 24 hours, and then performing supercritical drying.

[0016] By adopting the above technical solution, the aged wet gel is placed in hexamethyldisilazane. Hexamethyldisilazane can react with the hydroxyl groups on the surface of the wet gel, thereby replacing the hydroxyl groups and forming hydrophobic silane groups on the surface of the wet gel, making the wet gel hydrophobic. This enables the modified silica aerogel to have good hydrophobic properties and a stable porous structure, thereby improving the moisture barrier performance of the high oxygen and moisture barrier PE film.

[0017] Preferably, the modified silica aerogel is further treated as follows: a silane coupling agent is added to an ethanol solution, mixed evenly, and then the modified silica aerogel is added. After ultrasonic vibration for 0.5-1 h, the mixture is centrifuged, filtered, and dried for later use. A crosslinking agent and a dispersant are added to a polyvinyl alcohol solution, carbon nanotubes are added and ultrasonically dispersed evenly, and then the modified silica aerogel is added and dispersed evenly. The mixture is directionally cooled with liquid nitrogen, completely frozen, and then freeze-dried. Finally, it is heat-treated at 140°C for 5 min to obtain a modified silica aerogel coated with PVA aerogel.

[0018] By adopting the above technical solution, coating PVA aerogel onto modified silica aerogel can effectively improve its dispersibility in polyvinyl alcohol emulsion, which is beneficial to improving the bonding strength between water-resistant modifier and polyvinyl alcohol. Carbon nanotubes have excellent mechanical properties, which can further improve the mechanical properties and strength of the material and improve the coating integrity of PVA aerogel.

[0019] Preferably, the concentration of the polyvinyl alcohol solution is 4.8-5.1 g / L, and the amount of carbon nanotubes added is 20.56-22.67 wt%.

[0020] By adopting the above technical solution, the concentration of the polyvinyl alcohol solution can be controlled, which can effectively control the fluidity of the polyvinyl alcohol solution, which is beneficial to the uniformity of PVA aerogel coating and has appropriate porosity. The amount of carbon nanotubes added can be controlled to avoid excessive agglomeration, thus avoiding affecting the material performance and processing technology. It can also ensure the stability and uniformity of the material, and improve the oxygen and moisture barrier performance of the modified silica aerogel and the entire high oxygen and moisture barrier PE film.

[0021] Secondly, this application provides a process for producing a high oxygen and moisture barrier PE film, employing the following technical solution:

[0022] A process for producing a high oxygen and moisture barrier PE film includes the following steps: melt-blending polyvinylidene fluoride and polyethylene to prepare a barrier layer blend; co-extruding the barrier layer blend with PE resin used to form a corona layer and a heat-sealing layer to prepare a substrate film; and corona-treating the surface of the corona layer of the substrate film to obtain a high oxygen and moisture barrier PE film.

[0023] By adopting the above technical solution, the PE film produced has good mechanical strength, high moisture and oxygen barrier properties, and good transparency due to its simple structure, high PE content, and ability to be used for packaging printing, making it more aesthetically pleasing.

[0024] In summary, this application has the following beneficial effects:

[0025] 1. Because the high oxygen and moisture barrier PE film in this application adopts a structural design of sequentially connected corona layer, barrier layer and heat seal layer, the corona layer can improve the adhesion of the film surface and facilitate subsequent processing. The barrier layer includes polyethylene and polyvinylidene chloride. Polyethylene has good flexibility and processing performance, while polyvinylidene chloride has excellent oxygen and moisture barrier properties. The combination of the two enables the barrier layer to effectively block the permeation of oxygen and water vapor. The heat seal layer is made of polyethylene material. Polyethylene has good heat sealing performance and can easily achieve heat sealing between films to form a complete packaging structure, thereby ensuring that the entire PE film has high oxygen and moisture barrier performance.

[0026] 2. In this application, a modified polyvinyl alcohol coating is brushed onto the surface of a high oxygen and moisture barrier PE film. The polyvinyl alcohol emulsion itself has certain film-forming and barrier properties, and can form a continuous film layer on the film surface, which has a certain barrier effect on oxygen and water vapor. The addition of a water-resistant modifier can further improve the water resistance of the coating. The water-resistant modifier can prevent water vapor from eroding the coating, prevent the coating from swelling, dissolving or degrading due to water absorption, thereby maintaining the integrity and stability of the coating and ensuring its barrier effect on oxygen and water vapor. At the same time, the water-resistant modifier can also effectively improve the water resistance of the modified polyvinyl alcohol coating, making the coating less prone to swelling or dissolving due to excessive humidity, which is conducive to maintaining the strength and integrity of the modified polyvinyl alcohol coating.

[0027] 3. In this application, tetraethyl orthosilicate can undergo hydrolysis and polycondensation under alkaline conditions. The addition of nano-silica can form a rigid network, which is beneficial to the formation of wet gel and improves the strength of aerogel. Water treatment can impart hydrophobicity to the wet gel, giving it better water resistance in subsequent use. The complex pores of the aerogel can effectively block water vapor and oxygen, thereby improving the oxygen and moisture barrier properties of the membrane material. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Preparation Examples of Water-Resistant Modifiers 1-10

[0030] Preparation Example 1

[0031] The water-resistant modifier is a modified silica aerogel. The preparation method of the modified silica aerogel includes the following steps: 1g of tetraethyl orthosilicate is added to 50mL of ethanol solution, the pH is adjusted to 5, after hydrolysis, an ethanol solution of ammonia is added to adjust the pH to 7, and nano silica is added. The amount of nano silica added is 3.65wt% of tetraethyl orthosilicate. After ultrasonic dispersion, it is allowed to stand to form a wet gel. After aging and hydrophobic treatment, the wet gel is subjected to supercritical drying to obtain the modified silica aerogel. The hydrophobic treatment of the modified silica aerogel includes the following steps: the aged wet gel is placed in 100mL of hexamethyldisilazane, allowed to stand for 24h, and then subjected to supercritical drying.

[0032] Preparation Example 2

[0033] The water-resistant modifier is a modified silica aerogel. The preparation method of the modified silica aerogel includes the following steps: 1.2g of tetraethyl orthosilicate is added to 80mL of ethanol solution, the pH is adjusted to 4, after hydrolysis, an ethanol solution of ammonia is added to adjust the pH to 8, and nano-silica is added. The amount of nano-silica added is 4.12wt% of tetraethyl orthosilicate. After ultrasonic dispersion, it is allowed to stand to form a wet gel. After aging and hydrophobic treatment, the wet gel is subjected to supercritical drying to obtain the modified silica aerogel. The hydrophobic treatment of the modified silica aerogel includes the following steps: the aged wet gel is placed in 150mL of hexamethyldisilazane, allowed to stand for 24h, and then subjected to supercritical drying.

[0034] Preparation Example 3

[0035] The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the amount of nano-silica added is 2.12 wt% of tetraethyl orthosilicate.

[0036] Preparation Example 4

[0037] The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the amount of nano-silica added is 5.32 wt% of tetraethyl orthosilicate.

[0038] Preparation Example 5

[0039] The difference between Preparation Example 5 and Preparation Example 1 is that in Preparation Example 5, the modified silica aerogel was further treated as follows: 0.25g of silane coupling agent KH-550 was added to 200mL of ethanol solution, mixed evenly, and then 2g of modified silica aerogel was added. After ultrasonic vibration for 0.5h, it was centrifuged, filtered, and dried for later use. 5mg of BTCA and 2.5g of sodium hypophosphite were added to 100mL of 4.8g / L polyvinyl alcohol solution, and carbon nanotubes were added and ultrasonically dispersed evenly. The amount of carbon nanotubes added was 20.56wt%. 0.25g of modified silica aerogel was added and dispersed evenly. It was directionally cooled with liquid nitrogen, completely frozen, and then freeze-dried. After heat treatment at 140℃ for 5min, modified silica aerogel coated with PVA aerogel was obtained.

[0040] Preparation Example 6

[0041] The difference between Preparation Example 6 and Preparation Example 1 is that in Preparation Example 6, the modified silica aerogel was further treated as follows: 0.2 g of silane coupling agent KH-550 was added to 150 mL of ethanol solution, mixed evenly, and then 1.5 g of modified silica aerogel was added. After ultrasonic vibration for 1 h, it was centrifuged, filtered, and dried for later use. 5 mg of BTCA and 2.5 g of sodium hypophosphite were added to 100 mL of 5.1 g / L polyvinyl alcohol solution, and carbon nanotubes were added and ultrasonically dispersed evenly. The amount of carbon nanotubes added was 22.67 wt%. 0.2 g of modified silica aerogel was added and dispersed evenly. It was directionally cooled with liquid nitrogen, completely frozen, and then freeze-dried. After heat treatment at 140 °C for 5 min, modified silica aerogel coated with PVA aerogel was obtained.

[0042] Preparation Example 7

[0043] The difference between Preparation Example 7 and Preparation Example 5 is that in Preparation Example 7, the amount of carbon nanotubes added is 15.21 wt%.

[0044] Preparation Example 8

[0045] The difference between Preparation Example 8 and Preparation Example 5 is that in Preparation Example 8, the amount of carbon nanotubes added is 26.51 wt%.

[0046] Preparation Example 9

[0047] The difference between Preparation Example 9 and Preparation Example 5 is that in Preparation Example 9, the amount of modified silica aerogel added to the polyvinyl alcohol solution is 0.1 g.

[0048] Preparation Example 10

[0049] The difference between Preparation Example 10 and Preparation Example 5 is that in Preparation Example 10, the amount of modified silica aerogel added to the polyvinyl alcohol solution is 0.35g. Example

[0050] Example 1

[0051] A high oxygen and moisture barrier PE film and process, comprising a corona layer, a barrier layer and a heat-sealing layer connected in sequence, wherein the barrier layer comprises the following raw materials in parts by weight: 90 kg polyethylene and 5 kg polyvinylidene chloride, and the heat-sealing layer is made of polyethylene material.

[0052] The process of the above-mentioned high oxygen and moisture barrier PE film includes the following steps: melt blending polyvinylidene fluoride and polyethylene to prepare a barrier layer blend; co-extruding the barrier layer blend with PE resin used to form a corona layer and a heat-sealing layer to prepare a substrate film; and corona treating the surface of the corona layer of the substrate film to obtain a high oxygen and moisture barrier PE film.

[0053] Example 2

[0054] A high oxygen and moisture barrier PE film and process, comprising a corona layer, a barrier layer and a heat-sealing layer connected in sequence, wherein the barrier layer comprises the following raw materials in parts by weight: 95 kg polyethylene and 10 kg polyvinylidene chloride, and the heat-sealing layer is made of polyethylene material.

[0055] The process of the above-mentioned high oxygen and moisture barrier PE film includes the following steps: melt blending polyvinylidene fluoride and polyethylene to prepare a barrier layer blend; co-extruding the barrier layer blend with PE resin used to form a corona layer and a heat-sealing layer to prepare a substrate film; and corona treating the surface of the corona layer of the substrate film to obtain a high oxygen and moisture barrier PE film.

[0056] Example 3

[0057] The difference between Example 3 and Example 1 is that in Example 3, the high oxygen and moisture barrier PE film also includes a modified polyvinyl alcohol coating. The modified polyvinyl alcohol coating includes the following raw materials in parts by weight: 15 kg of polyvinyl alcohol emulsion and 0.9 kg of water-resistant modifier. The water-resistant modifier is the water-resistant modifier obtained in Preparation Example 1.

[0058] Example 4

[0059] The difference between Example 4 and Example 1 is that in Example 4, the high oxygen and moisture barrier PE film also includes a modified polyvinyl alcohol coating. The modified polyvinyl alcohol coating includes the following raw materials in parts by weight: 20 kg of polyvinyl alcohol emulsion and 1.1 kg of water-resistant modifier. The water-resistant modifier is the water-resistant modifier obtained in Preparation Example 2.

[0060] Example 5

[0061] The difference between Example 5 and Example 3 is that in Example 5, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 3.

[0062] Example 6

[0063] The difference between Example 6 and Example 3 is that in Example 6, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 4.

[0064] Example 7

[0065] The difference between Example 7 and Example 3 is that in Example 7, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 5.

[0066] Example 8

[0067] The difference between Example 8 and Example 3 is that in Example 8, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 6.

[0068] Example 9

[0069] The difference between Example 9 and Example 3 is that in Example 9, the water-resistant modifier is the water-resistant modifier prepared in Preparation Example 7.

[0070] Example 10

[0071] The difference between Example 10 and Example 3 is that in Example 10, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 8.

[0072] Example 11

[0073] The difference between Example 11 and Example 3 is that in Example 11, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 9.

[0074] Example 12

[0075] The difference between Example 12 and Example 3 is that in Example 12, the water-resistant modifier used is the water-resistant modifier prepared in Preparation Example 10. Comparative Example

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that no polyvinylidene chloride was added in Comparative Example 1.

[0078] Performance testing

[0079] High oxygen and moisture barrier PE membranes were prepared according to the raw materials and processes of Examples 1-12 and Comparative Example 1. Their oxygen barrier performance and moisture barrier performance were tested and recorded in Table 1. The oxygen barrier performance test conditions were 23°C and 0%RH, and the moisture barrier performance test conditions were 38°C and 90%RH. The results are expressed as water vapor permeation volume and oxygen permeation volume.

[0080] Table 1. Oxygen and moisture barrier properties of high oxygen and moisture barrier PE films

[0081] project <![CDATA[Moisture barrier property / (m 2 ·24 h)]]> <![CDATA[Oxygen barrier property / (m 2 ·24 h·1 MPa)]]> Example 1 1.8 9.5 Example 2 1.6 8.8 Example 3 0.9 1.8 Example 4 0.8 1.6 Example 5 1.2 2.5 Example 6 1.4 3.2 Example 7 0.5 0.9 Example 8 0.4 0.8 Example 9 0.7 1.5 Example 10 0.6 1.3 Example 11 0.8 1.7 Example 12 0.7 1.6 Comparative Example 1 5.8 1800

[0082] As can be seen from Table 1, Examples 1-2, and Comparative Example 1, the PE films prepared in Examples 1-2 have high oxygen barrier and moisture barrier properties. Examples 1-2 added polyvinylidene chloride (PVDC) to polyethylene. PVDC has good oxygen and moisture barrier properties, and when blended with polyethylene, it gives the film excellent oxygen and moisture barrier properties. Polyethylene has good heat-sealing properties, which can easily achieve heat sealing between films to form a complete packaging structure, thus ensuring that the entire PE film has high oxygen and moisture barrier properties. Comparative Example 1 did not add PVDC, and its oxygen and moisture barrier properties were worse than those of Examples 1-2.

[0083] Compared with Examples 1-2, Examples 3-4 show improved oxygen barrier and moisture barrier properties. Examples 3-4 involve coating the membrane material with a coating composed of PVA emulsion and a water-resistant modifier, indicating that the modified polyvinyl alcohol coating enhances the oxygen and moisture barrier properties of the membrane material. The polyvinyl alcohol emulsion itself has certain film-forming and barrier properties, while the water-resistant modifier can improve the water resistance of the modified polyvinyl alcohol coating. Furthermore, the modified silica aerogel has a complex porous structure, which can further improve the coating's barrier properties against water vapor and oxygen, thereby improving the oxygen and moisture barrier properties of the membrane material.

[0084] Compared with Examples 3-4, Examples 5-6 showed a decrease in both oxygen barrier and moisture barrier properties. The water-resistant modifiers in Examples 5-6 were prepared by changing the amount of nano-silica added. In Example 3, the amount of nano-silica added was too low, resulting in insufficient strength of the aerogel network structure and weakened barrier effect against moisture and oxygen. In Example 4, the amount of nano-silica added was too high, causing the nano-silica to easily agglomerate, resulting in structural defects in the modified silica aerogel and thus reducing its barrier effect against moisture and oxygen.

[0085] Compared with Examples 3-4, Examples 7-8 show improved oxygen barrier and moisture barrier properties. The modified silica aerogel used in Examples 7-8 was also coated with PVA aerogel. The PVA aerogel coating layer improved the dispersibility and interfacial bonding of the modified silica aerogel in the PVA emulsion. In addition, carbon nanotubes were added to the PVA aerogel, which effectively improved the strength of the water-resistant modifier.

[0086] Compared with Examples 7-8, Examples 9-10 showed a decrease in both oxygen barrier and moisture barrier properties. When coating the PVA aerogel in Examples 9-10, the amount of carbon nanotubes added was changed. The amount added in Example 9 was too low, resulting in insufficient reinforcing effect of carbon nanotubes on the PVA aerogel. The amount added in Example 10 was too high, which easily caused the carbon nanotubes to agglomerate, resulting in structural defects in the PVA aerogel and a decrease in mechanical strength.

[0087] Compared with Examples 7-8, Examples 11-12 show a decrease in both oxygen barrier and moisture barrier properties. When coating the PVA aerogels in Examples 11-12, the amount of modified silica aerogel added to the PVA solution was changed. If the amount added is too low, the PVA aerogel will be over-coated, resulting in an uneven coating layer. If the amount added is too high, agglomeration and uneven dispersion will occur, making it difficult to coat the PVA aerogels.

[0088] 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 high oxygen and moisture barrier PE film characterized in that: The high oxygen and moisture barrier PE film comprises a corona layer, a barrier layer and a heat sealing layer connected in sequence, the barrier layer comprises the following raw materials in parts by weight: 90-95 parts of polyethylene, 5-10 parts of polyvinylidene chloride, the heat sealing layer is selected from polyethylene materials, and the high oxygen and moisture barrier PE film further comprises a modified polyvinyl alcohol coating layer, the modified polyvinyl alcohol coating layer comprises the following raw materials in parts by weight: 15-20 parts of polyvinyl alcohol emulsion and 0.9-1.1 parts of water-resistant modifier; The water-resistant modifier is modified silica aerogel, and a preparation method of the modified silica aerogel comprises the following steps: adding tetraethyl orthosilicate into an ethanol solution, adjusting the pH to 4-5, adding an ammonia ethanol solution to adjust the pH to 7-8 after hydrolysis, and adding nano-silica, the addition amount of the nano-silica is 3.65-4.12 wt% of the tetraethyl orthosilicate, after ultrasonic dispersion, the wet gel is formed by standing, the wet gel is aged, hydrophobic treated, and then supercritically dried to obtain the modified silica aerogel; The modified silica aerogel is further treated as follows: adding a silane coupling agent into an ethanol solution, mixing uniformly, adding the modified silica aerogel, ultrasonic oscillation for 0.5-1 h, centrifugation, filtration and drying to obtain the modified silica aerogel, adding a crosslinking agent and a dispersing agent into a polyvinyl alcohol solution with a concentration of 4.8-5.1 g / L, adding carbon nanotubes and ultrasonic dispersion, the addition amount of the carbon nanotubes is 20.56-22.67 wt%, adding the modified silica aerogel and dispersing uniformly, directional cooling by liquid nitrogen, complete freezing and freeze-drying, and then heat treatment at 140 DEG C for 5 min to obtain the modified silica aerogel coated with PVA aerogel.

2. The high oxygen and moisture barrier PE film according to claim 1, characterized in that: The hydrophobic treatment of the modified silica aerogel comprises the following steps: placing the aged wet gel in hexamethyldisilazane, standing for 24 h, and then supercritically drying.

3. The process for a high oxygen and moisture barrier PE film according to any one of claims 1-2, characterized in that: The method comprises the following steps: melt blending polyvinylidene fluoride and polyethylene to prepare a barrier layer blend; The barrier layer blend and PE resins used for forming the corona layer and the heat sealing layer are prepared into a base film by a co-extrusion process, the surface of the corona layer of the base film is subjected to corona treatment to obtain the high oxygen and moisture barrier PE film.