Preparation method of ultraviolet curing self-repairing polyethylene plastic film

Abstract

The invention relates to the technical field of plastic films, and discloses a preparation method of an ultraviolet curing self-repairing polyethylene plastic film, which comprises the following steps: taking phosphonitrilic chloride trimer and 2-methylene-1, 3-propylene glycol as raw materials, and reacting to obtain an intermediate product 1; the preparation method comprises the following steps: by taking 4-iodobenzaldehyde, selenium powder, mercaptoethylamine, allyl mercaptan and the like as raw materials, reacting to obtain an intermediate product 4; and adding the intermediate product 1 into polyethylene resin, carrying out extrusion granulation, and carrying out film forming by a casting machine to prepare the flame-retardant polyethylene film. Uniformly mixing acrylic acid, methacrylic acid, the intermediate product 4 and the like, spin-coating the flame-retardant polyethylene film with the mixture, and curing to obtain the ultraviolet curing self-repairing polyethylene plastic film. The polyethylene plastic film prepared by the invention has excellent flame retardant property, mechanical property and self-repairing property.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic films, in particular to a method for preparing an ultraviolet-cured self-repairing polyethylene plastic film. Background Art

[0002] Polyethylene is an important synthetic resin with the advantages of being non-toxic, lightweight, and inexpensive. It is widely used in the electrical, chemical, and food industries. The plastic films made from it are widely used in food packaging, pesticide films, and other fields. However, it is inevitably damaged by the external environment during use. If it is not detected in time, it will cause irreversible damage, affecting its service life. In addition, polyethylene has poor flame retardant properties. These defects seriously limit its scope of application.

[0003] For example, the patent application publication number CN 110655613 A discloses an ion-crosslinked ultra-high molecular weight polyethylene material with self-repairing function and a preparation method. This method uses UHMWPE, linear low-density polyethylene, etc. as raw materials. The polyethylene material prepared has excellent wear resistance, tensile strength and micro-crack self-repairing function, and can be mass-produced in the public chemical industry. However, it does not solve the problem of improving the flame retardancy of polyethylene materials.

[0004] For example, the patent application publication number CN 114736445 A discloses an antibacterial and flame-retardant polyethylene material and its preparation method, an antibacterial and flame-retardant polyethylene film and its preparation method. The invention uses polyethylene, antibacterial additives, flame retardants, etc. as raw materials. The film prepared has good antibacterial and flame-retardant properties, but does not improve the self-healing properties of the polyethylene film.

[0005] Based on this, the present invention provides a method for preparing a UV-curable self-healing polyethylene plastic film. Summary of the Invention

[0006] (1) Technical problems solved

[0007] In view of the deficiencies in the prior art, the present invention provides a method for preparing a UV-curable self-healing polyethylene plastic film. The prepared polyethylene plastic film has good flame retardant properties, mechanical properties and self-healing effects.

[0008] (2) Technical solution

[0009] A method for preparing a UV-curable self-repairing polyethylene plastic film, the preparation method being as follows:

[0010] A1. Adding the intermediate product 1 to a polyethylene resin, mixing the mixture in a high-speed mixer, extruding the mixture into pellets, and then adding the mixture to a casting machine to prepare a flame-retardant polyethylene film. Since the intermediate product 1 contains a triolefinic structure, the intermediate product 1 is introduced into the polyethylene. Firstly, the triolefinic structure on the surface of the film can be increased to facilitate the subsequent reaction. Secondly, the flame retardant properties of the material can be improved by utilizing the nitrogen and phosphorus flame retardant elements contained therein.

[0011] A2. Add acrylic acid, methacrylic acid, intermediate product 4, N-isobutoxymethyl acrylamide crosslinking agent, and photoinitiator into a beaker and stir evenly to obtain a light-curing solution; place the flame-retardant polyethylene film in a spin coater, drop the light-curing solution on the film, and spin-coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet-cured self-healing polyethylene plastic film. In this process, N-isobutoxymethyl acrylamide is used as a crosslinking agent, acrylic acid, methacrylic acid, and intermediate product 4 are active monomers, and the flame-retardant polyethylene film is used as a substrate. By evenly spin coating, ultraviolet light is used to cure the film. A curing method is provided to prepare a UV-curable self-healing polyethylene plastic film, wherein the unsaturated bonds (C=C double bonds) contained in the flame-retardant polyethylene film are used to undergo a free radical polymerization reaction with the unsaturated bonds contained in acrylic acid, methacrylic acid, and intermediate product 4, and the intermediate product 4 is grafted on the surface of the polyethylene film. Moreover, since the intermediate product 4 contains a double C=C double bond structure, it can generate more chemical cross-linking sites when polymerized with other double bond structures. In addition, due to its physical cross-linking sites, when subjected to external stress, these cross-linking sites can disperse the stress and improve the mechanical properties of the material.

[0012] Preferably, in A1, the mass ratio of the intermediate product 1 to the polyethylene resin is 0.5-2.5:100.

[0013] Preferably, in A2, the mass ratio of acrylic acid, methacrylic acid and intermediate product 4 is 1:1-1.2:0.1-0.5.

[0014] Preferably, in A2, the amount of the crosslinker is 8-12% of the total mass of acrylic acid, methacrylic acid, and intermediate product 4; the photoinitiator is photoinitiator 1173, and its amount is 4-6% of the total mass of acrylic acid, methacrylic acid, and intermediate product 4.

[0015] Preferably, in A1, the preparation method of the intermediate product 1 is as follows: under a nitrogen atmosphere, hexachlorocyclotriphosphazene and N,N-dimethylaniline are added to a dioxane solvent, stirred to dissolve, and then 2-methylene-1,3-propanediol is added thereto, wherein the molar ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline, and 2-methylene-1,3-propanediol is 1:6-8:3-4, the temperature is controlled at 90-100° C., and the reaction is stirred for 14-18 hours. After the reaction is completed, the reaction is filtered, distilled under reduced pressure, washed with deionized water, and dried to obtain the intermediate product 1. In this reaction, N,N-dimethylaniline is used as an acid-binding agent, and the chlorine atom in the hexachlorocyclotriphosphazene is substituted with the hydroxyl group of 2-methylene-1,3-propanediol to obtain the intermediate product 1, that is, an alkenyl structure is introduced into the intermediate product 1. The reaction scheme is as follows:

[0016] ;

[0017] Preferably, in A2, the preparation method of intermediate product 4 is:

[0018] AA1. Under a nitrogen atmosphere, 4-iodobenzaldehyde and selenium powder are added to a dimethyl sulfoxide solvent and stirred at room temperature for 20-40 minutes. Potassium hydroxide and copper oxide are then added thereto, stirred and mixed evenly, and the temperature is raised to 90-100° C. and the reaction is carried out for 20-26 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and extracted to obtain an intermediate product 2, wherein the molar ratio of 4-iodobenzaldehyde, selenium powder, potassium hydroxide, and copper oxide is 1:3-5:2-3:0.1-0.2. In this reaction, copper oxide is used as a catalyst, 4-iodobenzaldehyde and selenium powder are used as starting reactants, and a coupling reaction is performed to obtain an intermediate product 2. A dynamic reversible covalent bond - a diselenide bond is introduced into the intermediate product 2. The reaction route is:

[0019] ;

[0020] AA2. Add mercaptoethylamine and allyl mercaptan to 30% hydrogen peroxide, raise the temperature to 45-55° C., react for 5-8 hours, then add ethyl acetate and continue the reaction for 1-2 hours. After the reaction, separate and purify the liquid, take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate product 3, wherein the molar ratio of mercaptoethylamine and allyl mercaptan is 1:1. In this reaction, mercaptoethylamine and allyl mercaptan are used as raw materials, and intermediate product 3 is obtained by peroxidation reaction. A dynamically reversible covalent bond - a disulfide bond is introduced into intermediate product 3. The reaction route is:

[0021] ;

[0022] AA3, intermediate product 2 and intermediate product 3 are added to ethanol, stirred and dispersed, the temperature is first controlled at 30-35 ° C, formic acid is added thereto, stirred and mixed evenly, and then the temperature is raised to 75-80 ° C, and the reaction is carried out for 2-5 hours. After the reaction is completed, the intermediate product 4 is washed with ether, recrystallized, and dried to obtain the intermediate product 4, wherein the molar ratio of intermediate product 2 to intermediate product 3 is 1:2-2.2, and the reaction route is:

[0023] ;

[0024] The aldehyde group contained in intermediate product 2 and the amino group contained in intermediate product 3 undergo a Schiff base reaction to obtain intermediate product 4. The Schiff base structure is used as a bridge to link intermediate product 2 and intermediate product 3 together. The obtained intermediate product 4 contains not only a disulfide bond, a diselenide bond, but also a double Schiff base structure, which is also a dynamically reversible structure.

[0025] (3) Beneficial technical effects

[0026] The polyethylene plastic film prepared by the present invention contains flame-retardant phosphorus, nitrogen and sulfur elements. When burned, the phosphorus element can generate strong dehydrating substances such as phosphoric acid and metaphosphoric acid when heated, which promotes the dehydration of the material into carbon, and further generates a glass-like substance on the surface of the material, isolating the material from the external material transport and energy transfer, thereby achieving the purpose of flame retardancy; the sulfur and nitrogen elements therein can generate flame-retardant gases (such as NH3, NO2, H2S, SO2 and SO3) when heated, which dilute the content of flammable gases in the air while taking away heat, and synergistically assist in improving the flame retardant properties of the material.

[0027] The present invention introduces dynamic covalent bonds such as disulfide bonds, diselenide bonds and Schiff base structures into the material. When the material is damaged by the outside world, the covalent bonds inside the material undergo a reversible reaction, the network breaks and reorganizes to repair the cracks, and the self-healing performance of the polyethylene plastic film is improved.

[0028] Intermediate products 1 and 4 prepared by the present invention contain diene and triene structures, which undergo free radical polymerization with acrylic acid and methacrylic acid, generating numerous chemical and physical crosslinking sites. These crosslinking sites disperse stress when subjected to external stress, improving the material's mechanical properties. The polyethylene plastic film prepared by the present invention comprises a self-healing layer and a flame-retardant layer, the two layers being linked by chemical bonds. The polyethylene plastic film prepared by the present invention exhibits excellent flame retardancy, mechanical properties, and self-healing properties. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] Example 1

[0031] (1) Under nitrogen atmosphere, 20 mmol of hexachlorocyclotriphosphazene and 120 mmol of N,N-dimethylaniline were added to dioxane solvent and stirred to dissolve. Then, 80 mmol of 2-methylene-1,3-propanediol was added thereto. The temperature was controlled at 95 °C and the reaction was stirred for 18 h. After the reaction was completed, the mixture was filtered, evaporated under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0032] (2) Under nitrogen atmosphere, 10 mmol of 4-iodobenzaldehyde and 40 mmol of selenium powder were added to dimethyl sulfoxide solvent and stirred at room temperature for 30 min. Then, 25 mmol of potassium hydroxide and 1 mmol of copper oxide were added thereto and stirred to mix evenly. The mixture was heated to 100 °C and reacted for 25 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and extracted to obtain intermediate product 2.

[0033] (3) Add 80 mmol of mercaptoethylamine and 80 mmol of allyl mercaptan to 30% hydrogen peroxide, heat to 50°C, and react for 6 h. Then add ethyl acetate and continue to react for 2 h. After the reaction is completed, separate and purify the liquid. Take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate 3.

[0034] (4) Add 20 mmol of intermediate product 2 and 40 mmol of intermediate product 3 to ethanol, stir and disperse, first control the temperature to 35 °C, add 5 mL of formic acid, stir and mix evenly, then heat to 75 °C, react for 5 h, and after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

[0035] (5) 0.5 g of the intermediate product 1 was added to 100 g of polyethylene resin, mixed evenly in a high-speed mixer, and then placed in a twin-screw extruder. The temperatures of each zone of the twin-screw extruder were 160°C, 170°C, 175°C, 180°C, and 170°C, and the twin-screw speed was 50 r / min. The pellets were extruded and granulated. The pellets were then added to a casting machine. The temperatures of each zone of the casting machine were 160°C, 170°C, 180°C, 185°C, 185°C, and 170°C, and the speed was 45 r / min. Flame-retardant polyethylene film was prepared.

[0036] (6) Add 10 g of acrylic acid, 10 g of methacrylic acid, 1 g of intermediate product 4, 2.5 g of N-isobutyloxymethyl acrylamide crosslinker, and 1 g of photoinitiator 1173 into a beaker and stir evenly to obtain a photocurable solution; place a flame-retardant polyethylene film in a spin coater, drop the photocurable solution on the film, and spin coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet light-cured self-healing polyethylene plastic film.

[0037] Example 2

[0038] (1) Under nitrogen atmosphere, 20 mmol of hexachlorocyclotriphosphazene and 140 mmol of N,N-dimethylaniline were added to dioxane solvent and stirred to dissolve. Then, 70 mmol of 2-methylene-1,3-propanediol was added thereto. The temperature was controlled at 100 °C and the reaction was stirred for 14 h. After the reaction was completed, the product was filtered, evaporated under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0039] (2) Under nitrogen atmosphere, 10 mmol of 4-iodobenzaldehyde and 45 mmol of selenium powder were added to dimethyl sulfoxide solvent and stirred at room temperature for 30 min. Then, 30 mmol of potassium hydroxide and 1 mmol of copper oxide were added thereto and stirred to mix evenly. The mixture was heated to 95 °C and reacted for 22 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and extracted to obtain intermediate 2.

[0040] (3) Add 80 mmol of mercaptoethylamine and 80 mmol of allyl mercaptan to 30% hydrogen peroxide, heat to 50°C, and react for 6 h. Then add ethyl acetate and continue to react for 2 h. After the reaction is completed, separate and purify the liquid. Take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate 3.

[0041] (4) Add 20 mmol of intermediate product 2 and 42 mmol of intermediate product 3 to ethanol, stir and disperse, first control the temperature to 35 °C, add 5 mL of formic acid, stir and mix evenly, then heat to 75 °C, react for 4 h, and after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

[0042] (5) 1 g of the intermediate product 1 was added to 100 g of polyethylene resin, mixed evenly in a high-speed mixer, and then placed in a twin-screw extruder. The temperatures of each zone of the twin-screw extruder were 160°C, 170°C, 175°C, 180°C, and 170°C, and the twin-screw speed was 50 r / min. The pellets were extruded and granulated. The pellets were then added to a casting machine. The temperatures of each zone of the casting machine were 160°C, 170°C, 180°C, 185°C, 185°C, and 170°C, and the speed was 45 r / min. Flame-retardant polyethylene film was obtained.

[0043] (6) Add 10 g of acrylic acid, 12 g of methacrylic acid, 2 g of intermediate product 4, 2 g of N-isobutyloxymethyl acrylamide crosslinker, and 1 g of photoinitiator 1173 into a beaker and stir evenly to obtain a photocurable solution; place the flame-retardant polyethylene film in a spin coater, drop the photocurable solution on the film, and spin coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet light-cured self-healing polyethylene plastic film.

[0044] Example 3

[0045] (1) Under nitrogen atmosphere, 20 mmol of hexachlorocyclotriphosphazene and 160 mmol of N,N-dimethylaniline were added to dioxane solvent and stirred to dissolve. Then, 60 mmol of 2-methylene-1,3-propanediol was added thereto. The temperature was controlled at 90 °C and the reaction was stirred for 16 h. After the reaction was completed, the mixture was filtered, evaporated under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0046] (2) Under nitrogen atmosphere, 10 mmol of 4-iodobenzaldehyde and 30 mmol of selenium powder were added to dimethyl sulfoxide solvent and stirred at room temperature for 30 min. Then, 25 mmol of potassium hydroxide and 1 mmol of copper oxide were added thereto and stirred to mix evenly. The mixture was heated to 100 °C and reacted for 24 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and extracted to obtain intermediate product 2.

[0047] (3) Add 80 mmol of mercaptoethylamine and 80 mmol of allyl mercaptan to 30% hydrogen peroxide, heat to 50°C, and react for 8 h. Then add ethyl acetate and continue to react for 1 h. After the reaction is completed, separate and purify the liquid. Take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate 3.

[0048] (4) Add 20 mmol of intermediate product 2 and 44 mmol of intermediate product 3 to ethanol, stir and disperse, first control the temperature to 35 °C, add 5 mL of formic acid, stir and mix evenly, then heat to 75 °C, react for 3 h, after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

[0049] (5) 1.5 g of the intermediate product 1 was added to 100 g of polyethylene resin, mixed evenly in a high-speed mixer, and then placed in a twin-screw extruder. The temperatures of each zone of the twin-screw extruder were 160°C, 170°C, 175°C, 180°C, and 170°C, and the twin-screw speed was 50 r / min. The pellets were extruded and granulated. The pellets were then added to a casting machine. The temperatures of each zone of the casting machine were 160°C, 170°C, 180°C, 185°C, 185°C, and 170°C, and the speed was 45 r / min. Flame-retardant polyethylene film was prepared.

[0050] (6) Add 10 g of acrylic acid, 10 g of methacrylic acid, 3 g of intermediate product 4, 2 g of N-isobutyloxymethyl acrylamide crosslinker, and 1.2 g of photoinitiator 1173 into a beaker and stir evenly to obtain a photocurable solution; place the flame-retardant polyethylene film in a spin coater, drop the photocurable solution on the film, and spin coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet light-cured self-healing polyethylene plastic film.

[0051] Example 4

[0052] (1) Under nitrogen atmosphere, 20 mmol of hexachlorocyclotriphosphazene and 140 mmol of N,N-dimethylaniline were added to dioxane solvent and stirred to dissolve. Then, 75 mmol of 2-methylene-1,3-propanediol was added thereto. The temperature was controlled at 100 °C and the reaction was stirred for 15 h. After the reaction was completed, the product was filtered, evaporated under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0053] (2) Under nitrogen atmosphere, 10 mmol of 4-iodobenzaldehyde and 40 mmol of selenium powder were added to dimethyl sulfoxide solvent and stirred at room temperature for 20 min. Then, 30 mmol of potassium hydroxide and 2 mmol of copper oxide were added thereto and stirred to mix evenly. The mixture was heated to 90°C and reacted for 26 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and extracted to obtain intermediate product 2.

[0054] (3) Add 80 mmol of mercaptoethylamine and 80 mmol of allyl mercaptan to 30% hydrogen peroxide, heat to 55°C, and react for 5 h. Then add ethyl acetate and continue to react for 1 h. After the reaction is completed, separate and purify the liquid. Take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate product 3.

[0055] (4) Add 20 mmol of intermediate product 2 and 42 mmol of intermediate product 3 to ethanol, stir and disperse, first control the temperature to 30 °C, add 5 mL of formic acid, stir and mix evenly, then heat to 80 °C, react for 2 h, and after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

[0056] (5) Add 2 g of the intermediate product 1 to 100 g of polyethylene resin, mix them evenly in a high-speed mixer, and then place them in a twin-screw extruder. The temperatures of each zone of the twin-screw extruder are 160°C, 170°C, 175°C, 180°C, and 170°C, and the twin-screw speed is 50 r / min. Extrusion granulation is carried out, and then added to a casting machine. The temperatures of each zone of the casting machine are 160°C, 170°C, 180°C, 185°C, 185°C, and 170°C, and the speed is 45 r / min to prepare a flame-retardant polyethylene film.

[0057] (6) Add 10 g of acrylic acid, 12 g of methacrylic acid, 4 g of intermediate product 4, 3 g of N-isobutyloxymethyl acrylamide crosslinker, and 1.5 g of photoinitiator 1173 into a beaker and stir evenly to obtain a photocurable solution; place the flame-retardant polyethylene film in a spin coater, drop the photocurable solution on the film, and spin coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet-cured self-healing polyethylene plastic film.

[0058] Example 5

[0059] (1) Under nitrogen atmosphere, 20 mmol of hexachlorocyclotriphosphazene and 150 mmol of N,N-dimethylaniline were added to dioxane solvent and stirred to dissolve. Then, 70 mmol of 2-methylene-1,3-propanediol was added thereto. The temperature was controlled at 100 °C and the reaction was stirred for 14 h. After the reaction was completed, the product was filtered, evaporated under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0060] (2) Under nitrogen atmosphere, 10 mmol of 4-iodobenzaldehyde and 50 mmol of selenium powder were added to dimethyl sulfoxide solvent and stirred at room temperature for 40 min. Then, 20 mmol of potassium hydroxide and 2 mmol of copper oxide were added thereto and stirred to mix evenly. The mixture was heated to 95°C and reacted for 20 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and extracted to obtain intermediate product 2.

[0061] (3) Add 80 mmol of mercaptoethylamine and 80 mmol of allyl mercaptan to 30% hydrogen peroxide, heat to 45°C, and react for 6 h. Then add ethyl acetate and continue to react for 2 h. After the reaction is completed, separate and purify the liquid. Take the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate 3.

[0062] (4) Add 20 mmol of intermediate product 2 and 44 mmol of intermediate product 3 to ethanol, stir and disperse, first control the temperature to 30 °C, add 5 mL of formic acid, stir and mix evenly, then heat to 80 °C, react for 4 h, and after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

[0063] (5) Add 2.5 g of the intermediate product 1 to 100 g of polyethylene resin, mix them evenly in a high-speed mixer, and then place them in a twin-screw extruder. The temperatures of each zone of the twin-screw extruder are 160°C, 170°C, 175°C, 180°C, and 170°C, and the twin-screw speed is 50 r / min. Extrusion granulation is carried out, and then added to a casting machine. The temperatures of each zone of the casting machine are 160°C, 170°C, 180°C, 185°C, 185°C, and 170°C, and the speed is 45 r / min to prepare a flame-retardant polyethylene film.

[0064] (6) Add 10 g of acrylic acid, 12 g of methacrylic acid, 5 g of intermediate product 4, 2 g of N-isobutyloxymethyl acrylamide crosslinker, and 1 g of photoinitiator 1173 into a beaker and stir evenly to obtain a photocurable solution; place the flame-retardant polyethylene film in a spin coater, drop the photocurable solution on the film, and spin coat it. After the film is evenly spin-coated, place it in an ultraviolet curing agent for curing to obtain an ultraviolet light-cured self-healing polyethylene plastic film.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that step (5) does not contain intermediate product 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that step (6) does not contain intermediate product 4.

[0069] Use an oxygen index meter to test the limiting oxygen index of plastic film.

[0070] Use a vertical burning tester to test the vertical burning rating of plastic film.

[0071] Table 1:

[0072] Oxygen index (%) Vertical combustion level Example 1 26.8 V-0 Example 2 28.3 V-0 Example 3 29.7 V-0 Example 4 30.5 V-0 Example 5 31.0 V-0 Comparative Example 1 18.9 - Comparative Example 2 24.6 V-1

[0073] It can be seen from the table that the plastic film prepared by the present invention has excellent flame retardant properties.

[0074] Refer to GB / T1040.3-2006 and use a tensile testing machine to test the tensile strength of the plastic film.

[0075] Use scissors to cut the polyethylene plastic film, then place it at 80℃ for 12 hours for repair, and test the tensile strength again. The self-repair efficiency (%) = tensile strength after repair / tensile strength before repair × 100%.

[0076] Table 2:

[0077] Tensile strength (MPa) Self-study efficiency (%) Example 1 15.1 69.7 Example 2 16.7 73.4 Example 3 17.0 76.0 Example 4 19.4 79.2 Example 5 18.3 80.6 Comparative Example 1 11.6 69.2 Comparative Example 2 13.0 -

[0078] It can be seen from the table that the polyethylene plastic film prepared by the present invention has excellent mechanical properties and self-repairing effect.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a UV-curable self-repairing polyethylene plastic film, characterized in that: The preparation method is as follows: A1, adding intermediate product 1 to polyethylene resin, mixing evenly, extruding and granulating, and then adding to a casting machine to prepare a flame retardant polyethylene film; A2. Add acrylic acid, methacrylic acid, intermediate product 4, a cross-linking agent, and a photoinitiator into a beaker and stir evenly to obtain a photocurable solution; drop the photocurable solution onto a flame-retardant polyethylene film and spin-coat it. After the film is evenly spin-coated, place the film in an ultraviolet curing agent for curing to obtain a UV-curable self-healing polyethylene plastic film.

2. The method for preparing the UV-curable self-healing polyethylene plastic film according to claim 1, characterized in that: In the A1, the mass ratio of the intermediate product 1 to the polyethylene resin is 0.5-2.5:

100.

3. The method for preparing the UV-curable self-repairing polyethylene plastic film according to claim 1, characterized in that: In the A2, the mass ratio of acrylic acid, methacrylic acid and intermediate product 4 is 1:1-1.2:0.1-0.

5.

4. The method for preparing the UV-curable self-healing polyethylene plastic film according to claim 1, characterized in that: In A2, the crosslinking agent is N-isobutoxymethyl acrylamide, and its usage is 8-12% of the total mass of acrylic acid, methacrylic acid, and intermediate product 4; the photoinitiator is photoinitiator 1173, and its usage is 4-6% of the total mass of acrylic acid, methacrylic acid, and intermediate product 4.

5. The method for preparing the UV-curable self-repairing polyethylene plastic film according to claim 1, characterized in that: In A1, the preparation method of intermediate product 1 is as follows: under a nitrogen atmosphere, hexachlorocyclotriphosphazene and N,N-dimethylaniline are added to a dioxane solvent, stirred to dissolve, and then 2-methylene-1,3-propanediol is added thereto, wherein the molar ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline and 2-methylene-1,3-propanediol is 1:6-8:3-4, the temperature is controlled at 90-100°C, and the reaction is stirred for 14-18 hours. After the reaction is completed, the mixture is filtered, distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate product 1.

6. The method for preparing the UV-curable self-repairing polyethylene plastic film according to claim 1, characterized in that: In A2, the preparation method of intermediate product 4 is: AA1. Under a nitrogen atmosphere, add 4-iodobenzaldehyde and selenium powder to dimethyl sulfoxide solvent, stir at room temperature for 20-40 minutes, then add potassium hydroxide and copper oxide, stir and mix evenly, heat to 90-100°C, react for 20-26 hours, and after the reaction is completed, cool to room temperature, filter, wash, and extract to obtain intermediate 2; AA2, adding mercaptoethylamine and allyl mercaptan to 30% hydrogen peroxide, heating to 45-55°C, reacting for 5-8 hours, then adding ethyl acetate, and continuing the reaction for 1-2 hours. After the reaction is completed, separate and purify the liquid, collect the supernatant, dry it, filter it under reduced pressure, and distill it to obtain intermediate 3; AA3. Add intermediate product 2 and intermediate product 3 to ethanol, stir and disperse, first control the temperature to 30-35°C, add formic acid, stir and mix evenly, then heat to 75-80°C, react for 2-5h, after the reaction is completed, wash with ether, recrystallize, and dry to obtain intermediate product 4.

7. The method for preparing the UV-curable self-healing polyethylene plastic film according to claim 6, characterized in that: In the AA1, the molar ratio of 4-iodobenzaldehyde, selenium powder, potassium hydroxide, and copper oxide is 1:3-5:2-3:0.1-0.

2.

8. The method for preparing the UV-curable self-repairing polyethylene plastic film according to claim 6, characterized in that: In the AA2, the molar ratio of mercaptoethylamine to allyl mercaptan is 1:1-1.

1.

9. The method for preparing the UV-curable self-healing polyethylene plastic film according to claim 6, characterized in that: In the AA3, the molar ratio of the intermediate product 2 to the intermediate product 3 is 1:2-2.2.