Multifunctional composite film and production process thereof

Abstract

The invention relates to the technical field of PE films, in particular to a multifunctional composite film and a production process thereof, and the production process comprises the following steps: preparing a master batch A from low-density modified polyethylene in parts by weight, banburying the obtained master batch A with 0220KJ linear low-density polyethylene and 5401G type metallocene polyethylene to obtain an inner-layer film material, and banburying with 0220AA type polyethylene to obtain an outer-layer film material; finally, banburying with 0220KJ linear low-density polyethylene to obtain a middle-layer film material; the modified polyethylene comprises the following raw materials in parts by weight: 0.4-1.6 parts of a functional additive, 0.5-2 parts of an antioxidant, 0.5-2 parts of a light stabilizer, 5-12 parts of a dispersant, 3-8 parts of a lubricant, 0.5-2 parts of a tackifier, 10-20 parts of LLDPE, 1-5 parts of a silicon-aluminum molecular sieve, 2-8 parts of aluminum phosphate and 40-60 parts of HDPE; the tensile mechanical property and the oxidation resistance of the PE film are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of PE films, and specifically relates to a multifunctional composite film and its production process. Background Art

[0002] Polyethylene (PE) is a thermoplastic resin obtained by polymerizing ethylene, and also includes copolymers of ethylene and a small amount of α-olefins. Polyethylene has excellent chemical stability and can resist acids and alkalis at room temperature, but it is easily oxidized by light and heat and can also undergo photodegradation under ultraviolet light. Polyethylene also has excellent mechanical properties. Its crystalline part gives polyethylene higher strength, and its non-crystalline part gives it good flexibility.

[0003] In actual applications, PE films are prone to aging under the action of the atmosphere, sunlight, and oxygen, specifically manifested as a problem of decreased elongation mechanical properties. Summary of the Invention

[0004] The purpose of the present invention is to provide a multifunctional composite film and its production process. The technical problem solved by the present invention is that PE films are prone to aging under the action of the atmosphere, sunlight, and oxygen, specifically manifested as a problem of decreased elongation mechanical properties.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A production process of a multifunctional composite film, including the following steps: Extrude the raw materials of low-density modified polyethylene in parts by weight with a twin-screw extruder to obtain masterbatch A. Mix the obtained masterbatch A with 0220KJ linear low-density polyethylene and 5401G metallocene polyethylene by kneading to obtain the inner layer film material, and then knead it with 0220AA polyethylene to obtain the outer layer film material; finally, knead it with 0220KJ linear low-density polyethylene to obtain the middle layer film material; Co-extrude and cast stretch the inner layer film material, the middle layer film material, and the outer layer film material to prepare a multifunctional composite film; The modified polyethylene includes the following raw materials in parts by weight: 0.4 - 1.6 parts of functional additive, 0.5 - 2 parts of antioxidant, 0.5 - 2 parts of light stabilizer, 5 - 12 parts of dispersant, 3 - 8 parts of lubricant, 0.5 - 2 parts of tackifier, 10 - 20 parts of LLDPE, 1 - 5 parts of silica-alumina molecular sieve, 2 - 8 parts of aluminum phosphate, and 40 - 60 parts of HDPE.

[0006] As a further scheme of the present invention: The preparation process of the functional additive includes the following steps: Form a uniformly dispersed mixed solution of nano-silica and cationic surfactant in toluene solvent; add isocyanate silane coupling agent, and under the conditions of a temperature of 70 - 90 °C and a reaction time of 6 - 24 h, obtain isocyanate silane coupling agent-modified silica; Adjust nano titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water to a pH value ≤ 4, then stir for 30 min, neutralize with an alkali to neutrality, and then centrifuge and dry to obtain a nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose coated on its surface; Prepare a functional additive by using the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on its surface, silica modified with an isocyanate silane coupling agent, and a thioester antioxidant at 150 °C for 1 h under the condition of reaction temperature.

[0007] As a further scheme of the present invention: the mass ratio of nano-silica, cationic surfactant, isocyanate silane coupling agent, and toluene solvent is 100:5 - 30:5 - 30:3000 mL.

[0008] As a further scheme of the present invention: the nano-silica is nano-silica with hydroxyl groups on its surface, and its particle size is 10 - 100 nm.

[0009] As a further scheme of the present invention: the cationic surfactant is one of the alkyltrimethylammonium salt type, dialkyldimethylammonium salt type, and alkyldimethylbenzylammonium type in the quaternary ammonium salt cationic surfactants.

[0010] As a further scheme of the present invention: the mass ratio of nano titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water is 50:100:5 - 10:1000.

[0011] As a further scheme of the present invention: the mass ratio of the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on its surface, silica modified with an isocyanate silane coupling agent, and a thioester antioxidant is 5 - 20:10 - 100:1 - 12.

[0012] As a further scheme of the present invention: the thioester antioxidants include dilauryl thiodipropionate (DLTDP), distearyl thiodipropionate (DSTDP), ditridecyl thiodipropionate (DTDTDP).

[0013] A multifunctional composite film, which includes: The transparent film is divided into three layers. The material of the inner layer is 0220KJ linear low-density polyethylene, low-density modified polyethylene, and 5401G metallocene polyethylene. The materials of the outer layer include 0220AA polyethylene and low-density modified polyethylene. The materials of the middle layer include 0220KJ linear low-density polyethylene and low-density modified polyethylene.

[0014] As a further solution of the present invention: the ratio of 0220KJ linear low-density polyethylene, low-density modified polyethylene and 5401G metallocene polyethylene in the inner layer material is 2:1:2, the ratio of 0220AA polyethylene and low-density modified polyethylene in the outer layer material is 4:1, and the ratio of 0220KJ linear low-density polyethylene and low-density modified polyethylene in the middle layer material is 4:1.

[0015] Advantages of the present invention: For the functional additive prepared by the present invention, a synergistic mechanism of nano-silica (SiO2) + thioester antioxidant is utilized: hydroxyl groups on the surface of SiO2 form hydrogen bonds with thioesters to delay the migration of antioxidants; SiO2 fills micropores to reduce oxygen diffusion channels; thioesters decompose peroxides to inhibit catalytic oxidation on the surface of SiO2; Therefore, the synergistic mechanism of nano-SiO2 and thioester antioxidants is a deep integration of physical barrier and chemical repair: SiO2 provides physical protection through interface adsorption, oxygen barrier, and by-product adsorption; thioesters achieve chemical repair by decomposing peroxides and inhibiting free radical chain reactions; the synergistic effect is manifested as an extended lifespan of antioxidants, stable mechanical properties, and significant inhibition of oxidation reaction kinetics; Thus, adding the functional additive of nano-silica (SiO2) + thioester antioxidant to the composite film effectively improves the tensile mechanical properties and oxidation resistance of the PE film.

[0016] Furthermore, by compounding isocyanate silane coupling agent and nano-inorganic ultraviolet light shielding agent with the nano-silica (SiO2) + thioester antioxidant material, the isocyanate silane coupling agent has good thermal stability and can maintain excellent performance in high-temperature environments, effectively alleviating the phenomenon that thioesters are easily decomposed at high temperatures, and also has an auxiliary improvement effect on the high-temperature resistance of the PE film. The nano-inorganic ultraviolet light shielding agent can effectively alleviate the problems that nano-scale silica is prone to yellowing and has poor weather resistance when used in materials, and also has an auxiliary improvement effect on the antioxidant performance of the PE film. Specific embodiments

[0017] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Example 1

[0018] The embodiment of the present invention provides a production process of a multi-functional composite film, including: The transparent film is divided into three layers. The material of the inner layer is 0220KJ linear low-density polyethylene, low-density modified polyethylene, and 5401G metallocene polyethylene. The material of the outer layer includes 0220AA polyethylene and low-density modified polyethylene. The material of the middle layer includes 0220KJ linear low-density polyethylene and low-density modified polyethylene; In the material of the inner layer, the ratio of 0220KJ linear low-density polyethylene, low-density modified polyethylene, and 5401G metallocene polyethylene is 2:1:2. In the material of the outer layer, the ratio of 0220AA polyethylene and low-density modified polyethylene is 4:1. In the material of the middle layer, the ratio of 0220KJ linear low-density polyethylene and low-density modified polyethylene is 4:1; Among them, the modified polyethylene includes the following raw materials in parts by weight: 0.4 part of functional additive, 0.5 part of antioxidant, 0.5 part of light stabilizer, 5 parts of dispersant, 3 parts of lubricant, 0.5 part of tackifier, 10 parts of LLDPE, 1 part of silica-alumina molecular sieve, 2 parts of aluminum phosphate, and 40 parts of HDPE; Among them, the preparation process of the functional additive includes the following steps: Prepare coupling agent-modified silica: Nano-silica and cationic surfactant form a uniformly dispersed mixed solution in toluene solvent; add isocyanate silane coupling agent, and under the conditions of a temperature of 70 °C and a reaction time of 6 h, obtain isocyanate silane coupling agent-modified silica; Adjust nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water to a pH value of 4, then stir for 30 min, neutralize with alkali to neutral, and then centrifuge and dry to obtain a nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose coated on the surface; Prepare the functional additive under the conditions of 150 °C and a reaction temperature of 1 h with the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on the surface, isocyanate silane coupling agent-modified silica, and thioester antioxidant; Among them, the mass ratio of nano-silica, cationic surfactant, isocyanate silane coupling agent, and toluene solvent is 100:5:5:3000 mL; the nano-silica is nano-silica with hydroxyl groups on the surface, and its particle size is 10 nm; the cationic surfactant is one of alkyltrimethylammonium salt type, dialkyldimethylammonium salt type, and alkyldimethylbenzylammonium type in quaternary ammonium salt cationic surfactants; The mass ratio of nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water is 50:100:5:1000; The mass ratio of a nano-inorganic ultraviolet light shielding agent with a surface coated with a carboxymethyl cellulose salt, silica modified with an isocyanate-based silane coupling agent, and a thioester antioxidant is 5:10:1; Among them, the thioester antioxidants include dilauryl thiodipropionate (DLTDP), distearyl thiodipropionate (DSTDP), and ditridecyl thiodipropionate (DTDTDP); The embodiments of the present invention provide a multi-functional composite film and its production process, including: The embodiments of the present invention also provide a production process for a multi-functional composite film, including the following steps: Step 1: Extrude the weight portion raw materials of low-density modified polyethylene with a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220KJ linear low-density polyethylene and 5401G metallocene polyethylene in a kneader and then enter a pressure kneader for kneading to obtain the inner layer film material; Step 2: Extrude the weight portion raw materials of low-density modified polyethylene with a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220AA type polyethylene in a kneader and then enter a pressure kneader for kneading to obtain the outer layer film material; Step 3: Extrude the weight portion raw materials of low-density modified polyethylene with a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220KJ linear low-density polyethylene in a kneader and then enter a pressure kneader for kneading to obtain the middle layer film material; Step 4: Add the inner layer film material, the middle layer film material, and the outer layer film material into an extrusion casting machine for co-extrusion casting and stretching to prepare a multi-functional composite film. Example Two

[0019] The embodiments of the present invention provide a production process for a multi-functional composite film, including: The transparent film is divided into three layers. The material of the inner layer is 0220KJ linear low-density polyethylene, low-density modified polyethylene, and 5401G metallocene polyethylene. The material of the outer layer includes 0220AA type polyethylene and low-density modified polyethylene. The material of the middle layer includes 0220KJ linear low-density polyethylene and low-density modified polyethylene; In the material of the inner layer, the ratio of 0220KJ linear low-density polyethylene, low-density modified polyethylene, and 5401G metallocene polyethylene is 2:1:2. In the material of the outer layer, the ratio of 0220AA type polyethylene and low-density modified polyethylene is 4:1. In the material of the middle layer, the ratio of 0220KJ linear low-density polyethylene and low-density modified polyethylene is 4:1; Among them, the modified polyethylene includes the following weight portion raw materials: 1.0 part of functional additive, 1 part of antioxidant, 1 part of light stabilizer, 8 parts of dispersant, 6 parts of lubricant, 1 part of tackifier, 15 parts of LLDPE, 3 parts of silica-alumina molecular sieve, 5 parts of aluminum phosphate and 50 parts of HDPE; Among them, the preparation process of the functional additive includes the following steps: Prepare coupling agent-modified silica: Nano-silica and cationic surfactant form a uniformly dispersed mixed solution in toluene solvent; isocyanate silane coupling agent is added, and under the conditions of a temperature of 80 °C and a reaction time of 15 h, silica modified by isocyanate silane coupling agent is obtained; Adjust nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water to a pH value of 3, then stir for 30 min, neutralize with alkali to neutral, and then centrifuge and dry to obtain a nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose coated on the surface; The nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on the surface, the silica modified by isocyanate silane coupling agent, and the thioester antioxidant are prepared to obtain the functional additive under the conditions of 150 °C and a reaction temperature of 1 h; Among them, the mass ratio of nano-silica, cationic surfactant, isocyanate silane coupling agent, and toluene solvent is 100:20:20:3000 mL; the nano-silica is nano-silica with hydroxyl groups on the surface, and its particle size is 30 nm; the cationic surfactant is one of alkyltrimethylammonium salt type, dialkyldimethylammonium salt type, and alkyldimethylbenzylammonium type in quaternary ammonium salt cationic surfactants; The mass ratio of nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water is 50:100:5 - 10:1000; The mass ratio of the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on the surface, the silica modified by isocyanate silane coupling agent, and the thioester antioxidant is 13:50:6; Among them, the thioester antioxidant includes dilauryl thiodipropionate (DLTDP), distearyl thiodipropionate (DSTDP), and ditridecyl thiodipropionate (DTDTDP); The embodiment of the present invention provides a multifunctional composite film and its production process, including: The embodiment of the present invention also provides a production process of a multifunctional composite film, including the following steps: Step 1: Extrude the raw material of low-density modified polyethylene with a weight part by a twin-screw extruder to obtain masterbatch A, knead the obtained masterbatch A with 0220KJ linear low-density polyethylene and 5401G metallocene polyethylene in a kneader, and then enter a pressure kneader for kneading to obtain an inner layer film material; Step 2: Extrude the raw materials of low-density modified polyethylene by a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220AA type polyethylene in a kneader and then enter a pressure internal mixer for internal mixing to obtain the outer layer film material; Step 3: Extrude the raw materials of low-density modified polyethylene by a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220KJ linear low-density polyethylene in a kneader and then enter a pressure internal mixer for internal mixing to obtain the middle layer film material; Step 4: Add the inner layer film material, the middle layer film material and the outer layer film material into an extrusion casting machine for co-extrusion casting and stretching to prepare a multi-functional composite film. Example Three

[0020] The embodiment of the present invention provides a production process of a multi-functional composite film, including: The transparent film is divided into three layers. The material of the inner layer is 0220KJ linear low-density polyethylene, low-density modified polyethylene and 5401G type metallocene polyethylene. The material of the outer layer includes 0220AA type polyethylene and low-density modified polyethylene. The material of the middle layer includes 0220KJ linear low-density polyethylene and low-density modified polyethylene; In the material of the inner layer, the ratio of 0220KJ linear low-density polyethylene, low-density modified polyethylene and 5401G type metallocene polyethylene is 2:1:2. In the material of the outer layer, the ratio of 0220AA type polyethylene and low-density modified polyethylene is 4:1. In the material of the middle layer, the ratio of 0220KJ linear low-density polyethylene and low-density modified polyethylene is 4:1; Among them, the modified polyethylene includes the following raw materials in parts by weight: 1.6 parts of functional additive, 2 parts of antioxidant, 2 parts of light stabilizer, 5 - 12 parts of dispersant, 8 parts of lubricant, 2 parts of tackifier, 20 parts of LLDPE, 5 parts of silica-alumina molecular sieve, 8 parts of aluminum phosphate and 60 parts of HDPE; Among them, the preparation process of the functional additive includes the following steps: Prepare coupling agent modified silica: Nano-silica and cationic surfactant form a uniformly dispersed mixed solution in toluene solvent; add isocyanate silane coupling agent, and obtain isocyanate silane coupling agent modified silica under the conditions of a temperature of 90 °C and a reaction time of 24 h; Adjust nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose and water to a pH value of 2, then stir for 30 min, neutralize with alkali to neutrality, and then centrifuge and dry to obtain a nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose coated on the surface; A functional additive is prepared by reacting a nano-inorganic ultraviolet light shielding agent with its surface coated with a hydroxymethyl cellulose salt, silica modified with an isocyanate-based silane coupling agent, and a thioester antioxidant at 150 °C for 1 h. Among them, the mass ratio of nano-silica, cationic surfactant, isocyanate-based silane coupling agent, and toluene solvent is 100:30:30:3000 mL; the nano-silica is nano-silica with hydroxyl groups on its surface, and its particle size is 100 nm; the cationic surfactant is one of the alkyltrimethylammonium salt type, dialkyldimethylammonium salt type, and alkyldimethylbenzylammonium type in quaternary ammonium salt-based cationic surfactants. The mass ratio of nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water is 50:100:10:1000. The mass ratio of the nano-inorganic ultraviolet light shielding agent with its surface coated with a hydroxymethyl cellulose salt, silica modified with an isocyanate-based silane coupling agent, and a thioester antioxidant is 20:100:12. Among them, the thioester antioxidants include dilauryl thiodipropionate (DLTDP), distearyl thiodipropionate (DSTDP), and ditridecyl thiodipropionate (DTDTDP). An embodiment of the present invention provides a multifunctional composite film and its production process, including: An embodiment of the present invention also provides a production process for a multifunctional composite film, including the following steps: Step 1: Extrude the raw materials of low-density modified polyethylene in parts by weight through a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220KJ linear low-density polyethylene and 5401G metallocene polyethylene in a kneader and then enter a pressure kneader for kneading to obtain an inner layer film material. Step 2: Extrude the raw materials of low-density modified polyethylene in parts by weight through a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220AA polyethylene in a kneader and then enter a pressure kneader for kneading to obtain an outer layer film material. Step 3: Extrude the raw materials of low-density modified polyethylene in parts by weight through a twin-screw extruder to obtain masterbatch A. Knead the obtained masterbatch A with 0220KJ linear low-density polyethylene in a kneader and then enter a pressure kneader for kneading to obtain a middle layer film material. Step 4: Add the inner layer film material, middle layer film material, and outer layer film material into an extrusion casting machine for co-extrusion casting and stretching to prepare a multifunctional composite film.

[0021] Comparative Example 1 Comparative Example 1 uses the multifunctional composite film disclosed in Chinese Patent No. CN111070618 A. Performance test: The performance of the multifunctional composite films of Examples 1-3 and Comparative Example 1 was tested. The test results are as follows:

[0022] As can be seen from the above table, the multifunctional composite films prepared in Examples 1-3 of the present invention have good tensile mechanical properties and oxidation resistance, which will effectively improve their service performance during use. The above has described in detail an embodiment of the present invention, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A production process of a multifunctional composite film, characterized in that, It includes the following steps: Extrude the raw materials of low-density modified polyethylene by weight to obtain masterbatch A. Mix the obtained masterbatch A with 0220KJ linear low-density polyethylene and 5401G metallocene polyethylene by internal mixing to obtain the inner layer film material, and then mix it with 0220AA polyethylene by internal mixing to obtain the outer layer film material; finally, mix it with 0220KJ linear low-density polyethylene by internal mixing to obtain the middle layer film material; Co-extrude and cast stretch the inner layer film material, the middle layer film material and the outer layer film material to prepare a multi-functional composite film; The modified polyethylene includes the following raw materials by weight: 0.4 - 1.6 parts of functional additive, 0.5 - 2 parts of antioxidant, 0.5 - 2 parts of light stabilizer, 5 - 12 parts of dispersant, 3 - 8 parts of lubricant, 0.5 - 2 parts of tackifier, 10 - 20 parts of LLDPE, 1 - 5 parts of silica-alumina molecular sieve, 2 - 8 parts of aluminum phosphate and 40 - 60 parts of HDPE.

2. The production process of a multifunctional composite film according to claim 1, characterized in that, The preparation process of the functional additive includes the following steps: Form a uniformly dispersed mixed solution of nano-silica and cationic surfactant in toluene solvent; add isocyanate silane coupling agent, and under the conditions of temperature of 70 - 90 °C and reaction time of 6 - 24 h, obtain isocyanate silane coupling agent modified silica; Adjust nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water to a pH value ≤ 4, then stir for 30 min, neutralize with alkali to neutral, and then centrifuge and dry to obtain a nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose coated on the surface; Prepare the functional additive under the conditions of 150 °C and reaction temperature of 1 h with the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on the surface, isocyanate silane coupling agent modified silica, and thioester antioxidant.

3. The production process of a multifunctional composite film according to claim 2, characterized in that, The mass ratio of nano-silica, cationic surfactant, isocyanate silane coupling agent, and toluene solvent is 100:5 - 30:5 - 30:3000 mL.

4. The production process of a multifunctional composite film according to claim 2, characterized in that The nano-silica is nano-silica with hydroxyl groups on the surface, and its particle size is 10 - 100 nm.

5. The production process of a multifunctional composite film according to claim 2, characterized in that The cationic surfactant is one of alkyltrimethylammonium salt type, dialkyldimethylammonium salt type, and alkyldimethylbenzylammonium type in quaternary ammonium salt cationic surfactants.

6. The production process of a multifunctional composite film according to claim 2, characterized in that, The mass ratio of nano-titanium dioxide, concentrated sulfuric acid with a mass fraction of 98%, sodium carboxymethyl cellulose, and water is 50:100:5 - 10:1000.

7. The production process of a multifunctional composite film according to claim 2, characterized in that, The mass ratio of the nano-inorganic ultraviolet light shielding agent with sodium carboxymethyl cellulose salt coated on the surface, isocyanate silane coupling agent modified silica, and thioester antioxidant is 5 - 20:10 - 100:1 - 12.

8. The production process of a multifunctional composite film according to claim 2, characterized in that, The thioester antioxidant includes dilauryl thiodipropionate (DLTDP), distearyl thiodipropionate (DSTDP), ditridecyl thiodipropionate (DTDTDP).

9. A multifunctional composite film, characterized in that, The multi-functional composite film is prepared by the process described in any one of claims 1 - 9, and the multi-functional composite film includes: The transparent film is divided into three layers. The material of the inner layer is 0220KJ linear low-density polyethylene, low-density modified polyethylene and 5401G metallocene polyethylene. The material of the outer layer includes 0220AA polyethylene and low-density modified polyethylene. The material of the middle layer includes 0220KJ linear low-density polyethylene and low-density modified polyethylene.

10. A multifunctional composite film according to claim 9, characterized in that, In the material of the inner layer, the ratio of 0220KJ linear low-density polyethylene, low-density modified polyethylene and 5401G metallocene polyethylene is 2:1:

2. In the material of the outer layer, the ratio of 0220AA polyethylene and low-density modified polyethylene is 4:

1. In the material of the middle layer, the ratio of 0220KJ linear low-density polyethylene and low-density modified polyethylene is 4:1.

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