A high-barrier polyolefin composite film and a method for preparing the same

Abstract

The application relates to the field of packaging films, and particularly discloses a high-barrier polyolefin composite film and a preparation method thereof. The high-barrier polyolefin composite film comprises, from outside to inside, a PE outer film, a water-blocking layer, a PVA high-barrier coating layer, a bonding layer and a PE inner film. The PE inner film comprises the following raw materials in percentage by weight: 10-20% of HDPE, 30-50% of MDPE, 20-26% of LLDPE, 10-20% of LDPE, 8-12% of water-oxygen blocking masterbatch and 1-3% of an additive. The water-oxygen blocking masterbatch comprises the following raw materials in parts by weight: 10-20 parts of polycarbonate, 0.1-0.3 parts of a compatilizer, 10-20 parts of ethylene-vinyl acetate copolymer, 1-2 parts of monolayer graphene and 1-2 parts of cage polysilsesquioxane. The high-barrier polyolefin composite film has the advantages of high water-oxygen blocking capacity, high tensile strength, good transparency and convenient recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packaging film, more particularly, it relates to a high-barrier polyolefin composite film and a preparation method thereof. BACKGROUND

[0002] At present, the commonly used high-barrier composite film is mainly composed of BOPET12, AL9, and PE50. The thickness of the composite packaging film is about 73 microns. Due to the aluminum foil, the composite packaging film has high barrier properties (oxygen and water resistance). However, due to the non-transparent nature of the aluminum foil, the packaging cannot display the appearance of the packaged product. In addition, with the gradual increase of global plastic pollution, the use of a large amount of adhesive to tightly bond the multi-layer film of different materials makes the peeling, sorting and adhesive removal of the multi-layer film extremely difficult, resulting in the composite film made of multiple materials cannot be recycled, which aggravates the global white pollution.

[0003] In order to solve the non-transparent problem of high-barrier packaging, various barrier films have been developed in the industry, such as EVOH high-barrier co-extruded film, silicon oxide, and aluminum oxide film. However, such films are very expensive, which hinders the replacement and commercialization of such films, and affects secondary recycling and reuse.

[0004] PE and PP are the most widely used high molecular materials in the world today. PE is a high molecular material with simple structure, low cost and good mechanical properties. PP is a linear structure similar to PE, but with a methyl side group every other carbon atom on the main chain, resulting in three different isomers in the spatial structure. PE and PP can be molded by blending, injection, extrusion and blow molding. PE film and PP film are a kind of semi-transparent, soft film, which is easy to recycle and has good chemical stability, temperature resistance and heat sealing property. It is mainly used for surface protection of products with high surface condition requirements and is often used for food packaging. Its price is low, but PE and PP are low-barrier materials, which have poor barrier properties for water vapor and oxygen, and cannot effectively prevent the penetration of oxygen from the external environment and the evaporation of internal water vapor. SUMMARY

[0005] In order to improve the barrier properties of single material PP film or PE film, the present application provides a high-barrier polyolefin composite film and a preparation method thereof.

[0006] In a first aspect, the present application provides a high-barrier polyolefin composite film, which adopts the following technical solution:

[0007] A high-barrier polyolefin composite film, from outside to inside, an outer film, a water barrier layer, a PVA high-barrier coating layer, an adhesive layer and an inner film, when the outer film is a PP outer film, the inner film is a PP inner film, when the outer film is a PE outer film, the inner film is a modified PE inner film;

[0008] The modified PE inner film comprises the following raw materials by weight percentage: 10-20% HDPE, 30-50% MDPE, 20-26% LLDPE, 10-20% LDPE, 8-12% water and oxygen barrier masterbatch, 1-3% auxiliary agent;

[0009] The water and oxygen barrier masterbatch comprises the following raw materials by weight: 10-20 parts of polycarbonate, 0.1-0.3 parts of a compatibilizer, 10-20 parts of ethylene-vinyl acetate copolymer, 1-2 parts of single-layer graphene, and 1-2 parts of cage-type poly siesquioxane.

[0010] By adopting the above technical scheme, the PE outer layer film and the modified PE inner layer film of a single material or the PP outer layer film and the PP inner layer film of a single material are bonded and compounded, which is easy to recycle; the low-density polyethylene, high-density polyethylene, linear low-density polyethylene and the like are used in the raw material of the modified PE inner layer film, the linear low-density polyethylene and the low-density polyethylene have high strength, good toughness, high rigidity, good heat resistance and cold resistance, good environmental stress cracking resistance, excellent impact resistance and tear resistance, the high-density polyethylene has small water vapor and air permeability, low water absorption and good barrier property, although the environmental stress cracking resistance of the high-density polyethylene is not as good as that of the low-density polyethylene; the water and oxygen blocking masterbatch contains polycarbonate, ethylene-vinyl acetate copolymer and single-layer graphene, when the water and oxygen blocking masterbatch is prepared into the modified PE inner layer film, the ethylene-vinyl acetate copolymer can improve the flexibility and environmental stress cracking resistance of the PE material, improve the permanent deformation of the modified PE inner layer film, increase the tear resistance, reduce the sensitivity of the modified PE inner layer film to the notch, when the polycarbonate is mixed with the low-density polyethylene and the high-density polyethylene, the ester exchange reaction can occur under the action of the compatibilizer, so that the polycarbonate is uniformly dispersed in the modified PE inner layer film, the EVA is a copolymer of ethylene, has good compatibility with the HDPE, and the side group is a functional group capable of reacting with the polycarbonate, in the process of blending, extruding and blowing, the ester exchange reaction occurs between the polycarbonate and the EVA in the molten state, a connection or crosslinked copolymer is formed at the interface, the compatibility of the polycarbonate and the HDPE blending system is improved, the dispersibility of the water and oxygen blocking masterbatch in the modified PE inner layer film is enhanced, the single-layer graphene sheet layer is prone to agglomeration, therefore, the steric hindrance caused by the adsorption of the cage polysilsesquioxane on the surface of the single-layer graphene makes the single-layer graphene more uniformly and stably dispersed, the single-layer graphene sheet layer is uniformly dispersed in the modified PE inner layer film, the permeation of water vapor and oxygen is blocked, and the barrier property is improved, the single-layer graphene has high transparency and biocompatibility, the light transmittance is above 97%, the single-layer graphene is almost completely transparent to the naked eye, and the addition of the polycarbonate and the EVA can further improve the tear resistance and puncture resistance of the modified PE inner layer film, and the polycarbonate and the EVA in the water and oxygen blocking masterbatch are both thermoplastic substances, when the polyolefin composite film is recycled, for example, when it is injection molded, the raw materials in the water and oxygen blocking masterbatch can be hot-melted, without affecting the recycling and injection molding of the polyolefin composite film.

[0011] Optionally, the water and oxygen blocking masterbatch is prepared as follows:

[0012] The ethylene-vinyl acetate copolymer is hot-melted, the cage polysilsesquioxane and the single-layer graphene purified by concentrated nitric acid are added, ultrasonic dispersion is performed for 1-2 h, and drying is performed at 50-60℃ until the weight is constant, to obtain the modified single-layer graphene.

[0013] Mixing, melting, extruding, granulating, and drying the modified single-layer graphene with polycarbonate and a compatibilizer.

[0014] By adopting the technical scheme, the single-layer graphene after purification has high purity and does not contain carbon impurities such as amorphous carbon, and the purification process does not damage the one-dimensional structure of the single-layer graphene. Moreover, the surface of the single-layer graphene after nitric acid purification generates many carboxyl and hydroxyl functional groups, which can increase the activity of the single-layer graphene. Moreover, there is a strong interaction between the carboxyl functional groups on the single-layer graphene and the EVA molecules, which can fix the single-layer graphene on the surface of the EVA, is conducive to the uniform dispersion of the single-layer graphene in the ethylene-vinyl acetate copolymer, and the EVA and the PC have good compatibility, and there is no obvious interface. By uniformly dispersing a high content of single-layer graphene in the EVA, the melting method can uniformly dilute the modified single-layer graphene in the polycarbonate. The presence of the EVA also greatly improves the interface strength between the PC and the PE, increases the interface interaction and the interface friction, and is conducive to the transmission of the load, thereby improving the mechanical properties such as the tensile strength, the elastic modulus, the elongation at break, and the toughness of the water-oxygen resistance master batch.

[0015] Optionally, the compatibilizer includes maleic anhydride grafted LDPE and maleic anhydride grafted ethylene-vinyl acetate with a mass ratio of 1:0.3-0.5.

[0016] By adopting the technical scheme, the main chain of the maleic anhydride grafted LDPE is compatible with the low-density polyethylene in the modified inner PE film, so that, in the process of melt extrusion for preparing the modified PE inner film, the maleic anhydride groups react with the carboxyl and hydroxyl end groups in the polycarbonate in situ at high temperature, so that chain entanglement occurs between the components, the intermolecular force is enhanced, the contact area between the two phases is increased, the compatibility of the low-density polyethylene, the linear low-density polyethylene, and the polycarbonate is significantly improved, the maleic anhydride grafted ethylene-vinyl acetate is a grafted or crosslinked copolymer of the polycarbonate and the ethylene-vinyl acetate, which can improve the compatibility of the polycarbonate and the high-density polyethylene, and the maleic anhydride grafted ethylene-vinyl acetate has excellent viscosity, which can increase the tightness between the components in the modified PE inner film, and further improve the barrier property of the composite film.

[0017] Optionally, the preparation of the PVA high-barrier coating solution includes the following steps:

[0018] Dissolve the carboxylated cellulose nanofiber to prepare a solution with a concentration of 0.8-1 wt%, add chitosan, ultrasonic dispersion, and freeze-drying and crushing to prepare aerogel powder;

[0019] Dissolve tannic acid to prepare a tannic acid solution with a concentration of 2-4 wt%, immerse the aerogel powder in the tannic acid solution for 5-10 min, and wash to prepare modified aerogel powder;

[0020] The polyvinyl alcohol is dissolved to prepare a polyvinyl alcohol aqueous solution with a concentration of 5-7 wt%, the modified aerogel powder and octadecyltrichlorosilane are added and uniformly mixed to prepare a PVA high-barrier coating liquid.

[0021] By adopting the technical scheme, the chitosan is a natural cationic polysaccharide, has good film-forming property, biodegradability, antioxidant property and antibacterial activity, the carboxylated cellulose nanofiber is a typical nanocellulose material, the nanocellulose chains can be intertwined with each other to serve as a carrier, has rich carboxyl groups, high crystallinity, high specific surface area and high transparency, excellent mechanical property, and the abundant hydroxyl groups promote the attraction of water molecules around the nanocellulose; the carboxyl groups and amino groups contained in the chitosan crosslink with the carboxylated cellulose nanofiber to form amide bonds, so that a network structure with good elasticity, high mechanical strength, good hydrophobicity and strong adsorption can be formed between the chitosan and the carboxylated cellulose nanofiber; the aerogel powder is immersed in a tannic acid solution, the tannic acid remains in the pores of the aerogel powder, and then the aerogel powder is immersed in a polyvinyl alcohol solution; the polyvinyl alcohol and the tannic acid are complexed through hydrogen bonds, a large number of hydrogen bonds can produce stable adhesion in the forming process, and the supermolecular adhesive with high polarity is formed, so that the adhesion of the PVA high-barrier coating to the outer film and the PE inner film is improved; finally, the octadecyltrichlorosilane is added, which is an alkylsilane and a material with low surface energy, can self-assemble on various substrates, and can make the coating layer have ultra-low surface energy and good hydrophobicity and water resistance after the PVA high-barrier coating liquid forms a coating layer, and the octadecyltrichlorosilane can form hydrogen bonds with the hydroxyl groups in the polyvinyl alcohol, so that the uniformity and stability of the octadecyltrichlorosilane on the surface of the coating layer are improved.

[0022] Optionally, the PVA high-barrier coating layer is formed by a PVA high-barrier coating liquid, and the PVA high-barrier coating liquid comprises the following raw materials in parts by weight: 1.5-2.2 parts of polyvinyl alcohol, 1-1.2 parts of carboxylated cellulose nanofiber, 0.8-1.2 parts of chitosan, 0.4-0.6 parts of tannic acid, and 1-1.5 parts of octadecyltrichlorosilane.

[0023] By adopting the technical scheme, the above raw materials can be used in the amounts to make the PVA high-barrier coating liquid form a coating layer with good compactness, low surface energy, strong hydrophobicity and water resistance on the water resistance layer.

[0024] Optionally, the water resistance layer is formed by curing after the water resistance adhesive is hot-melted, and the water resistance adhesive is prepared by the following method:

[0025] Mix 1-2 parts of polydimethylsiloxane, 10-20 parts of n-hexane and 0.1-0.2 parts of PDMS curing agent uniformly, add 0.5-1 parts of hydrophobic nano-silica, mix uniformly, dry at 80-90℃ for 1-2h, and ultrafine grind to prepare an intermediate, and mix 4-8 parts of EVA resin uniformly to prepare a water-resistant adhesive.

[0026] By adopting the technical scheme, polydimethylsiloxane (PDMS) is a flexible polymer material with excellent chemical stability and high flexibility, and its intermolecular force is weak, so the surface energy is low, and it has super-hydrophobic function. The surface of silica contains a large number of hydrophilic hydroxyl groups, so it is hydrophilic. The hydrophobic modification is carried out on the surface of the silica to connect the hydrophobic groups, so that the silica is more uniformly dispersed in the polydimethylsiloxane. The polydimethylsiloxane is used as an adhesive and is cured on the surface of the hydrophobic nano-silica, so that the silica has super-hydrophobic properties. After ultrafine grinding, the hydrophobic nano-silica is mixed with EVA resin. The EVA resin has good adhesion to many compounds, so it can increase the adhesion between the hydrophobic nano-silica particles and the outer film. The hydrophobic silica makes the outer film have a rough surface, thereby further improving the adhesion between the PVA high-barrier coating and the outer film. Moreover, the EVA resin has high transparency, softness and flexibility, and the surface energy is low, so the adhesion strength with the non-polar outer film is strong. Therefore, the barrier property of the outer film can be improved while the adhesion of the PVA high-barrier coating is improved. In addition, the EVA has good compatibility with PE and PP materials, and does not affect the performance of the polyolefin composite film recycling product during recycling of the polyolefin composite film.

[0027] Optionally, the adhesive layer is formed by curing an adhesive selected from one of a polyurethane adhesive, an epoxy resin adhesive and an acrylic resin adhesive.

[0028] By adopting the technical scheme, the polyurethane adhesive and other materials have long-lasting adhesion, which can make the outer film and the inner film adhere closely to form a composite film with high adhesion strength.

[0029] Optionally, the thickness ratio of the PE outer film to the modified PE inner film is 1-1.5:1.

[0030] By adopting the technical scheme, the above thickness ratio can better maintain the transparency of the PE composite film while maintaining its barrier property.

[0031] In a second aspect, the application provides a preparation method of a high-barrier polyolefin composite film, which adopts the following technical scheme:

[0032] A preparation method of a high-barrier polyolefin composite film, comprising the following steps:

[0033] The inner side of the outer film is subjected to corona treatment, the water-blocking adhesive is heated to 50-55 DEG C, coated on the side of the outer film subjected to corona treatment, dried, and a water-blocking layer is formed on the outer film;

[0034] The PVA high-barrier coating liquid is coated on the surface of the water-blocking layer, dried, and a PVA high-barrier coating layer is formed on the water-blocking layer;

[0035] A layer of adhesive is coated on the PVA high-barrier coating layer using a coating roller with a temperature of 35-50 DEG C, the inner film is compounded on the adhesive using hot pressing rollers with a temperature of 35-50 DEG C, the compounded film is cooled, pulled, wound, and aged, and a high-barrier polyolefin composite film is prepared.

[0036] By adopting the technical scheme, the outer film is coated to form a water-blocking layer and a PVA high-barrier coating layer, which can enhance the water vapor and oxygen barrier property of the outer film, thereby further improving the barrier property of the polyolefin composite film.

[0037] Optionally, the coating amount of the water-blocking adhesive is 1-3 g / m 2 , the coating amount of the PVA high-barrier coating liquid is 2-6 g / m 2 , and the coating amount of the adhesive is 1.2-4 g / m 2 .

[0038] By adopting the technical scheme, the water-blocking adhesive is coated on the side of the outer film subjected to corona treatment to form a water-blocking layer with a suitable thickness, which can achieve good water vapor barrier property without affecting the transparency of the composite film.

[0039] In summary, the present application has the following beneficial effects:

[0040] 1. Because this application uses linear low-density polyethylene, low-density polyethylene, and high-density polyethylene to prepare a modified PE inner layer film, and then composites it with a PE outer layer film, the resulting polyolefin composite film has strong resistance to environmental stress cracking and impact resistance, and does not affect secondary recycling. Furthermore, it adds a water- and oxygen-barrier masterbatch containing polycarbonate, ethylene-vinyl acetate copolymer, monolayer graphene, and cage-type polysilsesquioxane. The ethylene-vinyl acetate copolymer has good compatibility with polycarbonate, while the cage-type polysilsesquioxane can increase... The dispersibility of monolayer graphene in polycarbonate and ethylene-vinyl acetate allows it to form barrier channels in the modified PE inner layer membrane, increasing the barrier properties of the polyolefin composite membrane. In addition, the high transparency of ethylene-vinyl acetate, monolayer graphene, and polycarbonate does not affect the transparency of the polyolefin composite membrane. Furthermore, a single-material polypropylene composite membrane can be prepared using a PP outer layer membrane, a water-blocking layer, a PVA high-barrier coating, an adhesive layer, and a PP inner layer membrane, without affecting recycling and further improving the barrier capacity of the PP composite membrane.

[0041] 2. In this application, chitosan and carboxylated cellulose nanofibers are preferably cross-linked, freeze-dried, and pulverized to obtain an aerogel powder with a network structure. Then, a tannic acid solution is impregnated with the powder, and finally, a polyvinyl alcohol solution and octadecyltrichlorosilane are added to form a PVA high-barrier coating liquid. Hydrogen bonds are formed between the tannic acid and polyvinyl alcohol to form a supramolecular adhesive with high polar strength, which can increase the bonding strength between the PVA high-barrier coating and the water-blocking layer, while improving the water-blocking effect of the PVA high-barrier coating. Moreover, the cellulose nanofibers and chitosan have good transparency and do not affect the transparency of the polyolefin composite film.

[0042] 3. In this application, hydrophobic nano-silica is mixed with polydimethylsiloxane, pulverized, and then mixed with EVA resin to form a water-blocking adhesive. After being heated and melted, it flows and can form a dense and highly adhesive water-blocking layer on the outer membrane. EVA resin and polydimethylsiloxane have high transparency, low surface tension, and good water resistance. Without affecting the transparency of the polyolefin composite membrane, it improves its water vapor barrier ability and does not affect the recycling of the polyolefin composite membrane. Detailed Implementation

[0043] The following embodiments provide a further detailed description of this application.

[0044] Preparation Examples of Water-Barrier and Oxygen-Barrier Masterbatch 1-7

[0045] In Preparation Example 1, the ethylene-vinyl acetate copolymer was selected from Kuraray (Japan) and DuPont 40W (USA). At 190°C and 2.16 kg, the melt index was 52 g / 10 min, and the density was 0.965 g / cm³. 3, VA content is 40%, octaisobutyl poly siesquioxane is selected from Fosman Technology (Beijing) Co., Ltd., and the product number is 9502019, single-layer graphene is selected from Henglishengtai (Xiamen) Graphene Technology Co., Ltd., and the model number is TGF-I, polypropylene carbonate is selected from Wuhan Lanna Bai Pharmaceutical Chemical Co., Ltd., and the model number is PPC-001, maleic anhydride grafted LDPE is selected from Shanghai Xikaili Plastic Technology Co., Ltd., and the model number is E528, maleic anhydride grafted ethylene-vinyl acetate is selected from Dongguan Zhangmutou Hengtai Plastic Raw Material Co., Ltd., and the model number is SH-112A, and maleic anhydride grafted POE is selected from Guangzhou Chuanju Chemical Technology Co., Ltd., and the model number is EB-3008.

[0046] Preparation Example 1: 20g of ethylene-vinyl acetate copolymer is heated to 80℃, stirred and melted, 2g of cage polysilsesquioxane and 2g of single-layer graphene purified by concentrated nitric acid are added, ultrasonic dispersion is carried out for 2h, and drying is carried out at 60℃ until the weight is constant to obtain modified single-layer graphene, the cage polysilsesquioxane is octaisobutyl polysilsesquioxane, and the method for purifying single-layer graphene by concentrated nitric acid is as follows: single-layer graphene is mixed with 3mol / L of concentrated nitric acid, ultrasonic dispersion is carried out in a water bath at 80℃ while stirring for 8h, cooling is carried out to room temperature, suction filtration is carried out, deionized water washing is carried out until the pH value of the filtrate is centered, and drying is carried out at 120℃;

[0047] The modified single-layer graphene is mixed, melted, extruded, granulated and dried with 20g of polycarbonate and 0.3g of a compatibilizer, the compatibilizer includes maleic anhydride grafted LDPE and maleic anhydride grafted ethylene-vinyl acetate with a mass ratio of 1:0.5, and the polycarbonate is polypropylene carbonate made by copolymerization of carbon dioxide and propylene oxide.

[0048] Preparation Example 2: 10g of ethylene-vinyl acetate copolymer is heated to 80℃, stirred and melted, 1g of cage polysilsesquioxane and 1g of single-layer graphene purified by concentrated nitric acid are added, ultrasonic dispersion is carried out for 1h, and drying is carried out at 50℃ until the weight is constant to obtain modified single-layer graphene, the cage polysilsesquioxane is octaisobutyl polysilsesquioxane, and the method for purifying single-layer graphene by concentrated nitric acid is as follows: single-layer graphene is mixed with 3mol / L of concentrated nitric acid, ultrasonic dispersion is carried out in a water bath at 80℃ while stirring for 8h, cooling is carried out to room temperature, suction filtration is carried out, deionized water washing is carried out until the pH value of the filtrate is centered, and drying is carried out at 120℃;

[0049] The modified single-layer graphene is mixed, melted, extruded, granulated and dried with 10g of polycarbonate and 0.1g of a compatibilizer, the compatibilizer includes maleic anhydride grafted LDPE and maleic anhydride grafted ethylene-vinyl acetate with a mass ratio of 1:0.3, and the polycarbonate is polypropylene carbonate made by copolymerization of carbon dioxide and propylene oxide.

[0050] Preparation Example 3: The difference from Preparation Example 1 is that the compatibilizer is maleic anhydride grafted LDPE.

[0051] Preparation Example 4: The difference from Preparation Example 1 is that the compatibilizer is maleic anhydride grafted POE.

[0052] Preparation Example 5: The difference from Preparation Example 1 is that ethylene-vinyl acetate copolymer is not added.

[0053] Preparation Example 6: The difference from Preparation Example 1 is that single-layer graphene is not added.

[0054] Preparation Example 7: The difference from Preparation Example 1 is that cage polysilsesquioxane is not added.

[0055] Preparation Examples 8-12 of PVA high-barrier coating liquid

[0056] In Preparation Example 8, the carboxylated cellulose nanofiber is selected from Mcllri, with a diameter of 50 nm and a length of 1 μm, and the chitosan is selected from Mcllri, with a degree of deacetylation of ≥95%.

[0057] In Preparation Example 8, 1.2 g of carboxylated cellulose nanofiber is dissolved to form a solution with a concentration of 1 wt%, 1.2 g of chitosan is added, and the mixture is ultrasonically dispersed at a power of 200 W for 20 min, followed by freezing and drying at -60°C for 24 h, and then crushing to obtain aerogel powder.

[0058] 0.4 g of tannic acid is dissolved in distilled water to form a tannic acid solution with a concentration of 4 wt%, the prepared aerogel powder is immersed in the tannic acid solution for 10 min, and then washed with deionized water to obtain modified aerogel powder.

[0059] 2.2 g of polyvinyl alcohol 1788 is dissolved in distilled water to form a polyvinyl alcohol aqueous solution with a concentration of 7 wt%, the prepared modified aerogel powder and 1.5 g of octadecyltrichlorosilane are added and uniformly mixed to obtain a PVA high-barrier coating liquid.

[0060] In Preparation Example 9, 1.0 g of carboxylated cellulose nanofiber is dissolved to form a solution with a concentration of 0.8 wt%, 0.8 g of chitosan is added, and the mixture is ultrasonically dispersed at a power of 200 W for 20 min, followed by freezing and drying at -60°C for 24 h, and then crushing to obtain aerogel powder.

[0061] 0.6 g of tannic acid is dissolved in distilled water to form a tannic acid solution with a concentration of 2 wt%, the prepared aerogel powder is immersed in the tannic acid solution for 5 min, and then washed with deionized water to obtain modified aerogel powder.

[0062] 1.5 g of polyvinyl alcohol 1788 is dissolved in distilled water to form a polyvinyl alcohol aqueous solution with a concentration of 5 wt%, the prepared modified aerogel powder and 1.0 g of octadecyltrichlorosilane are added and uniformly mixed to obtain a PVA high-barrier coating liquid.

[0063] Preparation Example 10: The difference from Preparation Example 8 is that no chitosan is added.

[0064] Preparation Example 11: The difference from Preparation Example 8 is that no octadecyltrichlorosilane is added.

[0065] Preparation Example 12: 1.2 g of carboxylated cellulose nanofiber is dissolved to prepare a solution with a concentration of 1 wt%, 1.2 g of chitosan is added, and after ultrasonic dispersion at a power of 200 W for 20 min, it is frozen and dried at -60°C for 24 h, and then pulverized to prepare aerogel powder.

[0066] 2.2 g of polyvinyl alcohol 1788 is dissolved in distilled water to prepare a polyvinyl alcohol aqueous solution with a concentration of 7 wt%, and the prepared aerogel powder and 1.5 g of octadecyltrichlorosilane are added and uniformly mixed to prepare a PVA high-barrier coating liquid.

[0067] Preparation Examples 13-16 of water-blocking adhesive

[0068] In Preparation Example 13, the EVA resin is selected from Japan Kuraray, USA DuPont 40W, the melt index is 52 g / 10 min at 190°C and 2.16 kg, the density is 0.965 g / cm 3 , the VA content is 40%, the polydimethylsiloxane is selected from Guangzhou Shengrui Chemical Technology Co., Ltd., the model is PMA-200 500CS, the PDMS curing agent is selected from Dow Corning DC184, and the hydrophobic nano-silicon dioxide is selected from Hangzhou Jibin New Material Co., Ltd., the model is SS-S10B.

[0069] Preparation Example 13: 2 g of polydimethylsiloxane, 20 g of n-hexane and 0.2 g of PDMS curing agent are uniformly mixed, 1 g of hydrophobic nano-silicon dioxide is added and uniformly mixed, dried at 90°C for 1 h, and ultra-finely pulverized to prepare an intermediate with a particle size of 2 μm, which is uniformly mixed with 8 g of EVA resin to prepare a water-blocking adhesive, and the particle size of the silicon dioxide is 30 nm.

[0070] Preparation Example 14: 1 g of polydimethylsiloxane, 10 g of n-hexane and 0.1 g of PDMS curing agent are uniformly mixed, 0.5 g of hydrophobic nano-silicon dioxide is added and uniformly mixed, dried at 80°C for 2 h, and ultra-finely pulverized to prepare an intermediate with a particle size of 2 μm, which is uniformly mixed with 4 g of EVA resin to prepare a water-blocking adhesive, and the particle size of the silicon dioxide is 30 nm.

[0071] Preparation Example 15: The difference from Preparation Example 13 is that no hydrophobic nano-silicon dioxide is added.

[0072] Preparation Example 16: The difference from Preparation Example 13 is that no polydimethylsiloxane is added.

[0073] Example

[0074] The HDPE in Example 1 is selected from Sinopec Maoming, and the model number is HHM5502LW; the MDPE is selected from Dow, and the model number is HF513; the LLDPE is selected from Sinopec Maoming, and the model number is DFDA-7042; the LDPE is selected from Sinopec Maoming, and the model number is 2426K; the polyurethane adhesive is selected from Guangdong Xinhui Chemical Co., Ltd., and the model number is XH-66F; and the EVA resin is selected from Japan Kuraray, and the United States DuPont 40W, the melt index is 52g / 10min at 190℃ and 2.16kg, and the density is 0.965g / cm 3 , and the VA content is 40%.

[0075] Example 1: A high-barrier polyolefin composite film, from outside to inside, is PE outer film, water-blocking layer, PVA high-barrier coating layer, adhesive layer and modified PE inner film in sequence, the thickness of the PE outer film is 0.02mm, which is selected from Cangzhou Yongsheng Plastic Industry Co., Ltd., and the model number is XH001, the thickness of the modified PE inner film is 0.02mm, and the raw material usage of the modified PE inner film is shown in Table 1, wherein the water-blocking and oxygen-blocking masterbatch is prepared according to Preparation Example 1, and the auxiliary agent is antioxidant 1010.

[0076] The preparation method of the above high-barrier polyolefin composite film comprises the following steps:

[0077] S1, the inner side of the PE outer film is subjected to corona treatment, the corona treatment power is 3KW, the water-blocking adhesive is heated to 50℃ hot melt, and is coated on the side of the PE outer film subjected to corona treatment, dried, and a water-blocking layer is formed on the PE outer film, the water-blocking adhesive is EVA resin, and the coating amount of the water-blocking adhesive is 3g / m 2 ;

[0078] S2, the PVA high-barrier coating liquid is coated on the surface of the water-blocking layer, dried, and a PVA high-barrier coating layer is formed on the water-blocking layer, the preparation method of the PVA high-barrier coating liquid is: 2.2g of polyvinyl alcohol 1788 is dissolved with distilled water to prepare a polyvinyl alcohol aqueous solution with a concentration of 7wt%, and the coating amount of the PVA high-barrier coating liquid is 6g / m 2 ;

[0079] S3, the raw materials of the modified PE inner film are mixed, melted, extruded and blown according to the usage in Table 1 to prepare the PE inner film, the extrusion temperature is 160℃, the blow ratio is 3, and the draw ratio is 4;

[0080] S4, coating a layer of adhesive on the PVA high-barrier coating layer with a brushing roller at a temperature of 50℃, and compounding the modified PE inner layer film on the adhesive with a hot-pressing roller at 50℃, and cooling, pulling, winding and curing the compounded film to obtain a high-barrier polyolefin composite film, the pressure of the hot-pressing roller being 0.3 MPa, the pressing time being 0.5 mm / min, the adhesive being a polyurethane adhesive, the coating amount of the adhesive being 4 g / m 2 , the curing temperature of the compounded film being 35℃, and the curing time being 12 h.

[0081] Table 1 Raw material usage amount of modified inner layer PE film in high-barrier polyolefin composite film in Examples 1-4

[0082]

[0083] Example 2: A high-barrier polyolefin composite film, from outside to inside, comprising a PE outer layer film, a water-blocking layer, a PVA high-barrier coating layer, an adhesive layer and a modified PE inner layer film, the thickness of the PE outer layer film being 0.015 mm, selected from Cangzhou Yongsheng Plastic Industry Co., Ltd., with a product number of XH001, the thickness of the modified PE inner layer film being 0.01 mm, and the raw material usage amount of the modified PE inner layer film being shown in Table 1, wherein the water and oxygen blocking masterbatch is prepared according to Preparation Example 2.

[0084] The preparation method of the above high-barrier polyolefin composite film comprises the following steps:

[0085] S1, the inner side of the PE outer layer film is subjected to corona treatment at a power of 5 KW, the water-blocking adhesive is heated to 55℃ to be hot-melted, and is coated on the side of the PE outer layer film subjected to corona treatment, dried, and a water-blocking layer is formed on the PE outer layer film, the water-blocking adhesive being an EVA resin, and the coating amount of the water-blocking adhesive being 1 g / m 2 ;

[0086] S2, a PVA high-barrier coating liquid is coated on the surface of the water-blocking layer, dried, and a PVA high-barrier coating layer is formed on the water-blocking layer, the preparation method of the PVA high-barrier coating liquid being: 2.2 g of polyvinyl alcohol 1788 is dissolved in distilled water to prepare a polyvinyl alcohol aqueous solution with a concentration of 7 wt%, and the coating amount of the PVA high-barrier coating liquid being 2 g / m 2 ;

[0087] S3, the raw materials of the modified PE inner layer film are mixed, melted, extruded and blown according to the usage amount in Table 1 to obtain the modified PE inner layer film, the extrusion temperature being 160℃, the blow-up ratio being 3, and the pulling ratio being 4;

[0088] S4, coating a layer of adhesive on the PVA high-barrier coating layer with a brush roller at a temperature of 50°C, and compounding the modified PE inner layer film on the adhesive with a hot-pressing roller at 50°C, and cooling, pulling, winding and curing the compounded film to obtain a high-barrier polyolefin composite film, the pressure of the hot-pressing roller being 0.3 MPa, the pressing time being 0.5 mm / min, the adhesive being a polyurethane adhesive, and the coating amount of the adhesive being 1.2 g / m 2 The curing temperature of the compounded film is 35°C, and the curing time is 12 h.

[0089] Example 3-4: A high-barrier polyolefin composite film, which is different from Example 1 in that the raw material usage amount of the modified PE inner layer film is shown in Table 1.

[0090] Example 5: A high-barrier polyolefin composite film, which is different from Example 1 in that the water and oxygen barrier masterbatch in the modified PE inner layer film is made by Preparation Example 3.

[0091] Example 6: A high-barrier polyolefin composite film, which is different from Example 1 in that the water and oxygen barrier masterbatch in the modified PE inner layer film is made by Preparation Example 4.

[0092] Example 7: A high-barrier polyolefin composite film, which is different from Example 1 in that the PVA high-barrier coating solution is made by Preparation Example 8.

[0093] Example 8: A high-barrier polyolefin composite film, which is different from Example 1 in that the PVA high-barrier coating solution is made by Preparation Example 9.

[0094] Example 9: A high-barrier polyolefin composite film, which is different from Example 1 in that the PVA high-barrier coating solution is made by Preparation Example 10.

[0095] Example 10: A high-barrier polyolefin composite film, which is different from Example 1 in that the PVA high-barrier coating solution is made by Preparation Example 11.

[0096] Example 11: A high-barrier polyolefin composite film, which is different from Example 1 in that the PVA high-barrier coating solution is made by Preparation Example 12.

[0097] Example 12: A high-barrier polyolefin composite film, which is different from Example 7 in that the water-resistant adhesive is made by Preparation Example 13.

[0098] Example 13: A high-barrier polyolefin composite film, which is different from Example 7 in that the water-resistant adhesive is made by Preparation Example 14.

[0099] Example 14: A high-barrier polyolefin composite film, which is different from Example 12 in that the water-resistant adhesive is made by Preparation Example 15.

[0100] Example 15: A high-barrier polyolefin composite film, which is different from example 12 in that the water-blocking adhesive is made from Preparation Example 16.

[0101] Example 16: A high-barrier polyolefin composite film, which is made from, in order from outside to inside, a PP outer film, a water-blocking layer, a PVA high-barrier coating layer, an adhesive layer, and a PP inner film, the thickness of the PP outer film and the PP inner film is 0.02 mm, the PP outer film and the PP inner film are selected from Wenzhou Ruoguan Packaging Material Co., Ltd., and the product code is D05;

[0102] The preparation method of the above high-barrier polyolefin composite film comprises the following steps:

[0103] S1, the inner side of the PP outer film is subjected to corona treatment, the corona treatment power is 3 KW, the water-blocking adhesive is heated to 50°C hot melt, and is coated on the side of the PP outer film subjected to corona treatment, dried, and a water-blocking layer is formed on the PP outer film, the water-blocking adhesive is made from Preparation Example 13, and the coating amount of the water-blocking adhesive is 3 g / m 2 ;

[0104] S2, the PVA high-barrier coating liquid is coated on the surface of the water-blocking layer, dried, and a PVA high-barrier coating layer is formed on the water-blocking layer, the PVA high-barrier coating liquid is made from Preparation Example 8, and the coating amount of the PVA high-barrier coating liquid is 6 g / m 2 ;

[0105] S3, a layer of adhesive is coated on the PVA high-barrier coating layer using a coating roller with a temperature of 50°C, the PP inner film is compounded on the adhesive using a hot press roller with a temperature of 50°C, the compounded film is cooled, pulled, wound, and aged to obtain the high-barrier polyolefin composite film, the pressure of the hot press roller is 0.3 MPa, the pressing time is 0.5 mm / min, the adhesive is a polyurethane adhesive selected from Guangdong Xinhui Chemical Co., Ltd., the product code is XH-66F, the coating amount of the adhesive is 4 g / m 2 , and the aging temperature of the compounded film is 35°C and the aging time is 12 h.

[0106] Comparative Example

[0107] Comparative Example 1: A high-barrier polyolefin composite film, which is different from example 1 in that the water-blocking and oxygen-blocking masterbatch is made from Preparation Example 5.

[0108] Comparative Example 2: A high-barrier polyolefin composite film, which is different from example 1 in that the water-blocking and oxygen-blocking masterbatch is made from Preparation Example 6.

[0109] Comparative Example 3: A high-barrier polyolefin composite film, which is different from example 1 in that the water-blocking and oxygen-blocking masterbatch is made from Preparation Example 7.

[0110] Comparative Example 4: A high-barrier polyolefin composite film, which is different from example 1 in that no water-blocking and oxygen-blocking masterbatch is added.

[0111] Comparative Example 5: A high barrier polyolefin composite film, which is different from Example 1 in that no PVA high barrier coating is provided.

[0112] Comparative Example 6: A high barrier polyolefin composite film, which is different from Example 1 in that no water barrier layer is provided.

[0113] Comparative Example 7: A high barrier polyolefin composite film, which is different from Example 1 in that the PE inner film is selected from Cangzhou Yongsheng Plastic Industry Co., Ltd., with a product number of XH001 and a thickness of 0.02 mm.

[0114] Comparative Example 8: An antibacterial high oxygen barrier PE composite film, comprising a PE film layer and a PVA film layer, the PE film layer comprising the following raw materials by weight: linear low density polyethylene 100 parts, low density polyethylene 5 parts, low density PE-g-MAH 5 parts, antibacterial antistatic additive 12 parts; the PVA film layer comprising the following raw materials by weight: polyvinyl alcohol resin 100 parts, silicone oil 4 parts, propylene glycol 3 parts, polyethylene glycol 45 parts, talc 2 parts, polyethylene wax 10 parts; the preparation method is as follows: the materials of each layer of the outer PE film layer, the middle PVA film layer, and the inner PE film layer are heated and melted by a double screw extruder, wherein the heating temperature of the PE film layer 1-7 is as follows: 160℃, 170℃, 175℃, 180℃, 185℃, 175℃, 170℃, and the double screw rotation speed is 30 r / min. The middle PVA film layer: 180℃, 190℃, 195℃, 195℃, 210℃, 195℃, 180℃, and the double screw rotation speed is 30 r / min. The melt is extruded through a three-layer die, cooled into a cast sheet on a chill roll. The cast sheet is preheated in a 50℃ water bath, then treated for moisture adjustment in a 70℃ water bath, the moisture on the surface of the cast sheet is blown dry after moisture adjustment, and finally the product is wound by a conventional winding machine to obtain an antibacterial high oxygen barrier PE composite film.

[0115] Performance detection test

[0116] The composite films are prepared according to the methods in the examples and comparative examples, and the performance detection is carried out according to the following methods, and the detection results are recorded in Table 2.

[0117] 1. Tensile strength: detected according to GB / T13022-1991 "Plastic film tensile property test method standard", with a loading speed of 1 mm / min.

[0118] 2. Water vapor transmission rate: detected according to GB / T21529-2008 "Determination of water vapor transmission rate of plastic film and sheet", with a test temperature of 40℃ and a relative humidity of 90%.

[0119] 3. Oxygen transmission rate: According to GB / T 19789-2005 "Packaging materials - Plastic films and sheets - Determination of oxygen transmission rate - Coulometric method", the test temperature is 40°C and the relative humidity is 90%.

[0120] 4. Peel strength: According to GB 8808-1988 "Flexible sheeting - T-peel strength test method", the peel strength between the inner film and the outer film is detected.

[0121] 5. Transparency: According to GB / T 2410-2008 "Determination of transmission and haze of transparent plastics", the test is performed.

[0122] Table 2. Performance test results of high-barrier polyolefin composite film

[0123]

[0124] As can be seen from the data in Table 2, the water and oxygen barrier masterbatch prepared by using the preparation example 1 and the preparation example 2 in the example 1 and the example 2, respectively, the high-barrier polyolefin composite film prepared therefrom has good transparency, good barrier property to water vapor and oxygen, and strong adhesion between the outer PE film and the modified inner PE film.

[0125] The example 3 and the example 4 are compared with the example 1, the amount of raw materials is different, but the high-barrier polyolefin composite film prepared still has good barrier property, transparency and mechanical property.

[0126] The water and oxygen barrier masterbatch prepared by using the preparation example 3 and the preparation example 4 in the example 5 and the example 6, respectively, the maleic anhydride grafted LDPE and the maleic anhydride grafted POE are used as the compatibilizer in the preparation example 3 and the preparation example 4, respectively, compared with the example 1, the tensile strength of the high-barrier polyolefin composite film prepared in the example 5 and the example 6 decreases, the barrier property is weakened, and the adhesion between the outer PE film and the modified PE inner film decreases, which indicates that the maleic anhydride grafted LDPE and the maleic anhydride grafted EVA can effectively improve the compatibility of the water and oxygen barrier masterbatch with the raw material of the modified PE inner film, and increase the mechanical property and the barrier property of the modified PE inner film.

[0127] The example 7 and the example 8 are compared with the example 1, the PVA high-barrier coating liquid prepared by using the preparation example 8 and the preparation example 9, respectively, is used, as shown in Table 2, the tensile strength of the high-barrier polyolefin composite film prepared therefrom increases, the barrier property is further improved, and the adhesion between the outer PE film and the modified PE inner film increases.

[0128] The PVA high-barrier coating solution prepared in Example 9 using the high-barrier coating solution prepared in Preparation Example 10, compared with Example 8, does not add chitosan to the PVA high-barrier coating solution, the PVA high-barrier coating solution prepared in Example 10 using the high-barrier coating solution prepared in Preparation Example 11, wherein octadecyltrichlorosilane is not added, as shown in Table 2, the high-barrier polyolefin composite film prepared in Example 9 and Example 11 has little change in peel strength compared with Example 8, but the tensile strength decreases in Example 9 and the barrier ability weakens in Example 10.

[0129] The PVA high-barrier coating solution prepared in Example 11 using the high-barrier coating solution prepared in Preparation Example 12, compared with Example 8, does not use tannin to treat the aerogel powder, and thus the adhesion between the PE inner layer film and the PE outer layer film in the high-barrier polyolefin composite film prepared thereby decreases and the barrier property slightly weakens.

[0130] Example 12 and Example 13, compared with Example 7, respectively use the water-blocking adhesive prepared in Preparation Example 13 and Preparation Example 14, as shown in Table 2, the high-barrier polyolefin composite film prepared in Example 12 and Example 13 further reduces the barrier ability to water vapor, and the peel strength increases, indicating that the water-blocking adhesive can further improve the barrier property and adhesion of the PE composite film.

[0131] Example 14 and Example 15 respectively use the water-blocking adhesive prepared in Preparation Example 15 and Preparation Example 16, compared with Example 12, the PE composite film prepared in Example 14 reduces the water-blocking ability, weakens the mechanical property, and reduces the adhesion between the PE outer layer film and the modified PE inner layer film, and the PE composite film prepared in Example 15 weakens the water-blocking effect.

[0132] In Example 16, the PP outer layer film and the PP inner layer film are used as the substrate, the water-blocking layer, the PVA high-barrier coating layer and the adhesive layer are arranged between the PP outer layer film and the PP inner layer film, and the water-blocking adhesive is prepared by Preparation Example 13 and the PVA high-barrier coating solution is prepared by Preparation Example 8, and thus the polyolefin composite film prepared thereby has a barrier property to water vapor of 0.51 g / (m 2 ·24h) and a barrier property to oxygen of 0.23 cm 3 / (m 2 ·24h·0.1MPa), and has a good barrier ability.

[0133] In Comparative Example 1, the water-blocking and oxygen-blocking masterbatch prepared by Preparation Example 5 is used, compared with Example 1, ethylene-vinyl acetate copolymer is not added, and the tensile strength of the PE composite film prepared in Comparative Example 1 weakens and the water-blocking and oxygen-blocking ability decreases.

[0134] In Comparative Example 2, the water-blocking and oxygen-blocking masterbatch prepared by Preparation Example 6 is used, wherein single-layer graphene is not added, compared with Example 1, the water-blocking and oxygen-blocking ability of the PE composite film prepared in Comparative Example 2 weakens.

[0135] In Comparative Example 3, the water / oxygen barrier master batch prepared in Preparation Example 7 was used, and no cage polysilsesquioxane was added, and the barrier properties of the PEF composite film prepared thereby were weakened compared to Example 1, and the rest of the properties changed little.

[0136] In Comparative Example 4, no water / oxygen barrier master batch was added, and the barrier properties of the PEF composite film prepared thereby were significantly reduced compared to Example 1, and the tensile strength was also weakened.

[0137] Comparative Example 5 was not provided with a PVA high barrier coating, and Comparative Example 6 was not provided with a water barrier layer, and the test results in Table 2 show that the barrier properties of the PEF composite films prepared in Comparative Examples 5 and 6 were reduced, and the adhesion between the outer PE film and the inner PE film was reduced.

[0138] In Comparative Example 7, a commercially available PE film was used as the inner film, and the barrier properties of the PEF composite film prepared in Comparative Example 7 were significantly reduced.

[0139] Comparative Example 8 is a PEF composite film prepared according to the prior art, and the oxygen transmission rate is high, and the barrier properties to water vapor are poor, and the barrier properties need to be improved.

[0140] The specific embodiments are merely illustrative of the present application, and are not a limitation on the present application, and those skilled in the art can make modifications to the embodiments according to the needs without creative contribution, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high-barrier polyolefin composite film, characterized in that, From the outside in, the layers are: an outer membrane, a water-blocking layer, a PVA high-barrier coating, an adhesive layer, and an inner membrane. When the outer membrane is a PP outer membrane, the inner membrane is a PP inner membrane; when the outer membrane is a PE outer membrane, the inner membrane is a modified PE inner membrane. The modified PE inner membrane comprises the following raw materials by weight percentage: 10-20% HDPE, 30-50% MDPE, 20-26% LLDPE, 10-20% LDPE, 8-12% water- and oxygen-blocking masterbatch, and 1-3% additives. The water- and oxygen-blocking masterbatch comprises the following raw materials by weight parts: 10-20 parts polycarbonate, 0.1-0.3 parts compatibilizer, 10-20 parts ethylene-vinyl acetate copolymer, 1-2 parts monolayer graphene, and 1-2 parts cage-type polysilsesquioxane. The method for preparing the water- and oxygen-barrier masterbatch is as follows: Ethylene-vinyl acetate copolymer is hot-melted, cage-type polysilsesquioxane and monolayer graphene purified by concentrated nitric acid are added, ultrasonically dispersed for 1-2 hours, and dried at 50-60℃ to constant weight to obtain modified monolayer graphene; The modified monolayer graphene is mixed with polycarbonate and a compatibilizer, melted, extruded and granulated, and dried. The compatibilizer comprises maleic anhydride-grafted LDPE and maleic anhydride-grafted ethylene-vinyl acetate in a mass ratio of 1:0.3-0.

5. The PVA high-barrier coating is formed by a PVA high-barrier coating solution, which is prepared by the following steps: dissolving carboxylated cellulose nanofibers to prepare a solution with a concentration of 0.8-1 wt%, adding chitosan, ultrasonically dispersing, freeze-drying, and pulverizing to obtain aerogel powder; dissolving tannic acid to prepare a tannic acid solution with a concentration of 2-4 wt%, immersing the aerogel powder in the tannic acid solution for 5-10 minutes, washing, and obtaining modified aerogel powder; dissolving polyvinyl alcohol to prepare a polyvinyl alcohol aqueous solution with a concentration of 5-7 wt%, adding the modified aerogel powder and octadecyltrichlorosilane, mixing evenly, and obtaining the PVA high-barrier coating solution; The water-blocking layer is formed by hot-melting and curing a water-blocking adhesive. The water-blocking adhesive is prepared by the following method: by weight, 1-2 parts of polydimethylsiloxane, 10-20 parts of n-hexane and 0.1-0.2 parts of PDMS curing agent are mixed evenly, 0.5-1 parts of hydrophobic nano silica are added, mixed evenly, dried at 80-90℃ for 1-2 hours, and ultra-finely pulverized to obtain an intermediate. This intermediate is then mixed evenly with 4-8 parts of EVA resin to obtain the water-blocking adhesive.

2. The high-barrier polyolefin composite membrane according to claim 1, characterized in that: The PVA high-barrier coating liquid comprises the following raw materials in parts by weight: 1.5-2.2 parts polyvinyl alcohol, 1-1.2 parts carboxylated cellulose nanofibers, 0.8-1.2 parts chitosan, 0.4-0.6 parts tannic acid, and 1-1.5 parts octadecyltrichlorosilane.

3. The high-barrier polyolefin composite membrane according to claim 1, characterized in that: The adhesive layer is formed by curing an adhesive, which is selected from polyurethane adhesive, epoxy resin adhesive, and acrylic resin adhesive.

4. The high-barrier polyolefin composite membrane according to claim 1, characterized in that: The thickness ratio of the outer PE film to the modified PE inner film is 1-1.5:

1.

5. The method for preparing the high-barrier polyolefin composite film according to any one of claims 1-4, characterized in that: Includes the following steps: The inner side of the outer membrane is corona treated, and the water-blocking adhesive is heated to 50-55℃ and coated on the corona-treated side of the outer membrane. After drying, a water-blocking layer is formed on the outer membrane. A high-barrier PVA coating liquid is applied to the surface of the water-blocking layer and dried to form a high-barrier PVA coating on the water-blocking layer. A layer of adhesive is applied to a PVA high-barrier coating using a coating roller at a temperature of 35-50℃. The inner layer film is then laminated onto the adhesive using a hot press roller at a temperature of 35-50℃. The laminated film is then cooled, drawn, wound, and cured to obtain a high-barrier polyolefin composite film.

6. The method for preparing the high-barrier polyolefin composite film according to claim 5, characterized in that: The coating amount of the water-blocking adhesive is 1-3 g / m². 2 The coating amount of the PVA high-barrier coating liquid is 2-6 g / m³. 2 The adhesive application rate is 1.2-4 g / m². 2 .

Images