Quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas and preparation method thereof

Abstract

The present invention relates to the technical field of light-converting agricultural films, and in particular to a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas and a preparation method thereof. The quantum dot light-converting agricultural film comprises three structural functional layers stacked in sequence from top to bottom: a first nanoparticle protective film, a quantum dot intermediate film layer, and a second nanoparticle protective film; the quantum dot intermediate film layer is prepared by co-extrusion blow molding of a film after mixing a quantum dot material, a polymer material, a lubricant, and an anti-ultraviolet agent; the first nanoparticle protective film and the second nanoparticle protective film have the same structure, and are both prepared by co-extrusion blow molding of a film after mixing a metal nanoparticle, a polymer material, a lubricant, and an anti-ultraviolet agent. The advantages are: effectively solving the problem of quantum dot function failure and agricultural film aging caused by water molecules of condensed water penetrating into the agricultural film and generating activated oxygen under strong sunlight; converting light in other bands to the red light band required for photosynthesis of crops.

Description

Technical Field

[0001] The present invention relates to the technical field of light-converting agricultural films, and in particular to a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas and a preparation method thereof. Background Art

[0002] Facility agriculture is an important technology to ensure agricultural production. It has been widely promoted in the north and south of my country. It can provide stable climatic conditions, create an excellent environment suitable for the growth of crops in all seasons, and make the crop yield reach 3.5 times that of open-air cultivation. According to statistics, the output value of facility agriculture currently accounts for 22% of the total output value of my country's planting industry. In order to better convert and store energy in the process of photosynthesis, artificial lighting represented by quantum dot light-converting agricultural film has become one of the main means to ensure facility agricultural production. However, due to the short average sunshine time and weak sunshine intensity in winter in various parts of my country, as well as condensation and frost that reduce the transmittance of greenhouse film, the spectral intensity of red light (600nm-660nm) required for crop photosynthesis in the sunlight spectrum is much lower than that in summer, especially in the north where the temperature is lower in winter and the rainy season in the south. The water molecules of condensed water generated by the temperature difference between day and night will penetrate into the light-converting agricultural film, produce activated oxygen under strong sunlight, destroy the inherent structure of quantum dots, and cause the quantum dots to fail and the light-converting agricultural film to age, which will greatly reduce the service life of the light-converting agricultural film, resulting in a slowdown in the growth rate of crops and a decrease in yield, seriously affecting the stable supply of agricultural products. Therefore, there is an urgent need for a quantum dot light-converting agricultural film suitable for facility agriculture applications in high-cold and high-humidity areas, which can achieve photothermal heating and temperature control of the light-converting agricultural film, accelerate the evaporation of condensed water on the surface of the light-converting agricultural film, and extend the service life of the light-converting agricultural film. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a quantum dot light-conversion agricultural film suitable for high-cold and high-humidity areas and a preparation method thereof.

[0004] The present invention aims to provide a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas, comprising three structural functional layers stacked in sequence from top to bottom: a first nanoparticle protection film, a quantum dot intermediate film layer, and a second nanoparticle protection film;

[0005] The quantum dot intermediate film layer is prepared by mixing quantum dot material, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film; the first nanoparticle protective film and the second nanoparticle protective film have the same structure, and are both prepared by mixing metal nanoparticles, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film.

[0006] Preferably, the quantum dot material includes perovskite quantum dots, and at least one of quantum dots made from compounds of Groups II-VI, III-V, and IV-VI of the periodic table; the polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the lubricant is vinyl bisstearamide; the anti-ultraviolet agent is benzophenone; and the metal nanoparticles are gold nanoparticles or silver nanoparticles.

[0007] Preferably, the mass ratio of the quantum dot material to the polymer material is 1:5-40; the mass ratio of the metal nanoparticles to the polymer material is 1:40-100.

[0008] Preferably, the thickness of the quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas is 1-2 mm.

[0009] Preferably, it is prepared by the following method:

[0010] S1. Preparation of quantum dots by hot injection method;

[0011] S2. Preparation of metal nanoparticles by chemical reduction method;

[0012] S3. Preparation of masterbatch of quantum dot light-converting agricultural film intermediate layer: After the quantum dots and polyethylene material are uniformly mixed in proportion, the masterbatch of quantum dot light-converting agricultural film intermediate layer is prepared by extrusion granulation method;

[0013] S4. Preparation of a masterbatch of a nanoparticle protective film: After the metal nanoparticles and the polyethylene material are uniformly mixed in proportion, a masterbatch of a nanoparticle protective film is prepared by extrusion granulation;

[0014] S5. Add the masterbatch of the quantum dot light-converting agricultural film middle layer to the mixed solution of the polymer material, lubricant and anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 1300~2000r / min for 20~40min; after stirring evenly, the middle layer mixed solution is obtained, and added to the material tank of the film blowing machine to wait for film blowing;

[0015] S6. Add the masterbatch of the nanoparticle protective film to the mixed solution of the polymer material, the lubricant and the anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 800-1500 r / min for 40-60 min; after stirring evenly, the protective layer mixture is obtained, and added to the material tank of the film blowing machine to wait for film blowing;

[0016] S7. Set the die head temperature of the film blowing machine to 150-170°C and the melting temperature to 175-185°C, and use the middle nozzle of the film blowing machine to blow the middle layer mixture to obtain a quantum dot middle film layer; use the nozzles on both sides of the film blowing machine to blow the protective layer mixture to obtain a first nanoparticle protective film and a second nanoparticle protective film; and finally obtain a three-layer film structure of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas.

[0017] Preferably, the parameters of extrusion granulation in steps S3 and S4 are as follows: heating temperature 150-200° C., extrusion speed 300-800 r / min.

[0018] Preferably, the metal nanoparticles are gold nanoparticles; step S2 specifically includes the following sub-steps:

[0019] S201. Prepare chloroauric acid solution as a reaction material and sodium citrate solution as a reducing agent;

[0020] S202. The chloroauric acid solution is heated to 70-80° C. while stirring at a speed of 500-800 r / min, and the sodium citrate solution is quickly added to turn the solution orange-red;

[0021] S203. Continue heating and reflux for 8 to 15 minutes under vigorous stirring; stop heating, remove the heat source, continue stirring for 13 to 20 minutes and then stop stirring; cool the solution to room temperature to obtain a solution containing nano-gold particles.

[0022] Preferably, the polymer material is a polyethylene material; the lubricant is vinyl bisstearamide; and the anti-ultraviolet agent is benzophenone.

[0023] Preferably, the mass ratio of the masterbatch of the middle layer of the quantum dot light-converting agricultural film, the vinyl bisstearamide, the polyethylene material and the benzophenone is 10:5:100:1; the mass ratio of the masterbatch of the nanoparticle protective film, the vinyl bisstearamide, the polyethylene material and the benzophenone is 8:4:120:1.

[0024] Preferably, the quantum dots in step S1 are copper indium sulfide quantum dots; the copper indium sulfide quantum dots have a double shell layer structure, the first shell layer is zinc sulfide as the shell, and the second shell layer is formed by injecting a mixed solution of zinc source, thiol and octadecene into the first shell layer synthesis solution.

[0025] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0026] The quantum dot light-conversion agricultural film prepared by the present invention, which is suitable for high-cold and high-humidity areas, uses a metal nanoparticle film as a protective layer and a quantum dot light-conversion agricultural film to form a three-layer light-conversion film structure, which can effectively solve the problem that water molecules of condensed water generated by the temperature difference between day and night penetrate into the light-conversion agricultural film and generate activated oxygen under strong sunlight, thereby causing the quantum dots to fail and causing the light-conversion agricultural film to age.

[0027] The metal nanoparticles in the light-converting agricultural film can increase the surface temperature of the light-converting agricultural film through photo-induced heating, absorb the green light in the sunlight in the form of non-radiative compound and convert it into heat energy for release, accelerate the evaporation of condensed water on the surface of the light-converting agricultural film, and extend the service life of the light-converting agricultural film, providing a new option for facility agriculture in high-cold and high-humidity areas;

[0028] Quantum dot materials should have strong absorption in the ultraviolet, blue and yellow light bands, and be able to efficiently convert them into the red light band required for crop photosynthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the preparation process of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas provided according to an embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram of the structure and functional principle of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas provided according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram of temperature changes of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas and a common agricultural film under the same lighting environment according to an embodiment of the present invention.

[0032] Reference numerals:

[0033] 1. Copper indium sulfide quantum dots;

[0034] 2. Gold nanoparticles;

[0035] 3. Polyethylene material;

[0036] 4. The first nanoparticle protective film;

[0037] 5. Quantum dot intermediate film layer;

[0038] 6. Second nanoparticle protective film. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0041] The present invention provides a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas, comprising three structural functional layers stacked in sequence from top to bottom: a first nanoparticle protection film, a quantum dot intermediate film layer, and a second nanoparticle protection film;

[0042] The quantum dot intermediate film layer is prepared by mixing quantum dot material, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film; the first nanoparticle protective film and the second nanoparticle protective film have the same structure, and are both prepared by mixing gold nanoparticles, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film.

[0043] The quantum dot material includes perovskite quantum dots and at least one of quantum dots made from compounds of Groups II-VI, III-V, and IV-VI of the periodic table; the polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the lubricant is vinyl bisstearamide; and the anti-ultraviolet agent is benzophenone. In a specific embodiment, the polymer material is polyethylene material; the lubricant is vinyl bisstearamide; the anti-ultraviolet agent is benzophenone; and the metal nanoparticles are gold nanoparticles or silver nanoparticles.

[0044] The mass ratio of the quantum dot material to the polymer material is 1:5-40; the mass ratio of the metal nanoparticles to the polymer material is 1:40-100.

[0045] The thickness of the quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas is 1-2 mm; preferably, the thickness is 1.8 mm.

[0046] Specifically, the polyethylene material has a melt index of 25 g / 10 min.

[0047] The preparation method of quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas comprises the following steps:

[0048] S1. Preparation of quantum dots by hot injection method;

[0049] S2. Preparation of gold nanoparticles by chemical reduction method;

[0050] S3. Preparation of masterbatch of quantum dot light-converting agricultural film intermediate layer: After the quantum dots and the polyethylene material are uniformly mixed in proportion, the masterbatch of the quantum dot light-converting agricultural film intermediate layer is prepared by extrusion granulation;

[0051] S4. Preparation of a masterbatch of a nanoparticle protective film: After the gold nanoparticles and the polyethylene material are uniformly mixed in proportion, a masterbatch of a nanoparticle protective film is prepared by extrusion granulation;

[0052] S5. Add the masterbatch of the quantum dot light-converting agricultural film middle layer to the mixed solution of the polymer material, lubricant and anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 1300~2000r / min for 20~40min; after stirring evenly, the middle layer mixed solution is obtained, and added to the material tank of the film blowing machine to wait for film blowing;

[0053] S6. Add the masterbatch of the nanoparticle protective film to the mixed solution of the polymer material, the lubricant and the anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 800-1500 r / min for 40-60 min; after stirring evenly, the protective layer mixture is obtained, and added to the material tank of the film blowing machine to wait for film blowing;

[0054] S7. Set the die head temperature of the film blowing machine to 150-170°C and the melting temperature to 175-185°C, and use the middle nozzle of the film blowing machine to blow the middle layer mixture to obtain a quantum dot middle film layer; use the nozzles on both sides of the film blowing machine to blow the protective layer mixture to obtain a first nanoparticle protective film and a second nanoparticle protective film; and finally obtain a three-layer film structure of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas.

[0055] Preferably, the parameters of extrusion granulation in steps S3 and S4 are as follows: heating temperature 150-200° C., extrusion speed 300-800 r / min.

[0056] Preferably, step S2 specifically includes the following sub-steps:

[0057] S201. Prepare chloroauric acid solution as a reaction material and sodium citrate solution as a reducing agent;

[0058] S202. The chloroauric acid solution is heated to 70-80° C. while stirring at a speed of 500-800 r / min, and the sodium citrate solution is quickly added to turn the solution orange-red;

[0059] S203. Continue heating and reflux for 8 to 15 minutes under vigorous stirring; stop heating, remove the heat source, continue stirring for 13 to 20 minutes and then stop stirring; cool the solution to room temperature to obtain a solution containing nano-gold particles.

[0060] In a specific embodiment, the mass ratio of the masterbatch of the quantum dot light-converting agricultural film middle layer, the vinyl bisstearamide, the polyethylene material and the benzophenone is 10:5:100:1; the mass ratio of the masterbatch of the nanoparticle protective film, the vinyl bisstearamide, the polyethylene material and the benzophenone is 8:4:120:1.

[0061] In a specific embodiment, the quantum dots in step S1 are copper indium sulfide quantum dots; the copper indium sulfide quantum dots have a double shell layer structure, the first shell layer is zinc sulfide as the shell, and the second shell layer is formed by injecting a mixed solution of zinc source, mercaptan and octadecene into the first shell layer synthesis solution; specifically comprising the following sub-steps:

[0062] S101. 0.125mmol copper iodide (CuI), 0.5mmol indium acetate (In(C2H3O2)3), 2mmol dodecyl mercaptan (DDT) and 15mmol oleylamine (OLA) were injected into a three-necked flask to prepare a mixed reagent A solution; since the synthesis of quantum dots must be carried out in an oxygen-free environment, the mixed reagent A solution was degassed at 120°C for 15min and purged with nitrogen (N2) for 15min to remove oxygen;

[0063] S102. 3 mmol of sulfur powder was fully dissolved in 9 mmol of octadecene (ODE), and injected into the mixed reagent A solution at 250° C. to prepare a copper indium sulfur quantum dot synthesis solution;

[0064] S103. Preparation of the first shell layer synthesis solution of copper indium sulfide quantum dots: In order to improve the stability and luminescence efficiency of copper indium sulfide (CuInS2) quantum dots, zinc sulfide (ZnS) with a similar lattice and matching energy level structure arrangement to copper indium sulfide (CuInS2) quantum dots was selected as the shell. 5.3 mmol of zinc acetate dihydrate (C4H 10 O6Zn), 16.8mmol oleic acid (OA) and 8.3mmol octadecene (ODE) three kinds of solvents are slowly injected into the above copper indium sulfide quantum dot synthesis solution at a rate of 2.0ml / min respectively; after it is fully reacted for 30min, the first shell layer is gradually formed on the surface of copper indium sulfide (CuInS2) quantum dots to obtain the first shell layer synthesis solution of copper indium sulfide quantum dots;

[0065] S104. Preparation of copper indium sulfur quantum dot double shell layer synthesis solution: 5.3 mmol zinc stearate (C 36 H 70O4Zn), 11.1mmol dodecyl mercaptan (DDT) and 16.7mmol octadecene (ODE) were slowly injected into the first shell layer synthesis solution of copper indium sulfide quantum dots at a rate of 2.0ml / min, and after it was fully reacted for 2h, a second shell layer was gradually formed on the surface of the first shell layer of the quantum dots, forming a double-layer molecular coating structure. The copper indium sulfide quantum dot double shell layer synthesis solution was obtained; the copper indium sulfide quantum dot double shell layer synthesis solution was dried to obtain copper indium sulfide quantum dots.

[0066] Example 1

[0067] like Figure 1-Figure 2 As shown, this embodiment provides a method for preparing a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas, which specifically includes the following steps:

[0068] S1. Preparation of copper indium sulfur quantum dots 1 by hot injection method; specifically comprising the following sub-steps:

[0069] S101. 0.125mmol copper iodide (CuI), 0.5mmol indium acetate (In(C2H3O2)3), 2mmol dodecyl mercaptan (DDT) and 15mmol oleylamine (OLA) were injected into a three-necked flask to prepare a mixed reagent A solution; since the synthesis of quantum dots must be carried out in an oxygen-free environment, the mixed reagent A solution was degassed at 120°C for 15min and purged with nitrogen (N2) for 15min to remove oxygen;

[0070] S102. 3 mmol of sulfur powder is fully dissolved in 9 mmol of octadecene (ODE), and injected into the mixed reagent A solution at 250° C., and the nucleation process of the copper indium sulfur quantum dots 1 is regulated by high temperature conditions to prepare a copper indium sulfur quantum dot synthesis solution;

[0071] S103. Preparation of the first shell layer synthesis solution of copper indium sulfide quantum dots: In order to improve the stability and luminescence efficiency of copper indium sulfide (CuInS2) quantum dots, zinc sulfide (ZnS) with a similar lattice and matching energy level structure arrangement to copper indium sulfide (CuInS2) quantum dots was selected as the shell. 5.3 mmol of zinc acetate dihydrate (C4H 10 O6Zn), 16.8mmol oleic acid (OA) and 8.3mmol octadecene (ODE) three kinds of solvents are slowly injected into the above copper indium sulfide quantum dot synthesis solution at a rate of 2.0ml / min respectively; after it is fully reacted for 30min, the first shell layer is gradually formed on the surface of copper indium sulfide (CuInS2) quantum dots to obtain the first shell layer synthesis solution of copper indium sulfide quantum dots;

[0072] S104. Preparation of copper indium sulfur quantum dot double shell layer synthesis solution: 5.3 mmol zinc stearate (C 36 H70 O4Zn), 11.1mmol dodecyl mercaptan (DDT) and 16.7mmol octadecene (ODE) were slowly injected into the first shell layer synthesis solution of copper indium sulfide quantum dots at a rate of 2.0ml / min, and after being fully reacted for 2h, a second shell layer was gradually formed on the surface of the first shell layer of the quantum dots, forming a double-layer molecular coating structure. The copper indium sulfide quantum dot double shell layer synthesis solution was obtained; the copper indium sulfide quantum dot double shell layer synthesis solution was dried to obtain copper indium sulfide quantum dot 1.

[0073] S2. Preparation of gold nanoparticles 2 by chemical reduction method; specifically comprising the following sub-steps:

[0074] S201. The concentration is 2.44×10 -3 mol / L chloroauric acid (HAuCl4·4H2O) solution was used as the reaction material, and the concentration was 3.43×10 -2 mol / L sodium citrate (Na3C6H5O7·2H2O) solution as a reducing agent;

[0075] S202. Add 20 ml of chloroauric acid (HAuCl4·4H2O) solution to a 50 ml round-bottom flask, then place a magnet in the flask and connect a spherical condenser, place the flask on a digital speed-measuring constant-temperature magnetic stirrer, and stir while heating the flask. The stirring speed is set to 600 r / min, and the heating temperature of the flask is 75°C. While stirring at high speed, use a pipette to transfer 2 ml of the prepared sodium citrate (Na3C6H5O7·2H2O) solution and quickly add it to the chloroauric acid (HAuCl4·4H2O) solution at once. It can be observed that the color of the solution gradually changes from light yellow to orange-red.

[0076] S203. Start timing to make the color of the liquid constant and continue heating. After reflux for 10 min under intense stirring, stop heating and remove the heat source. Then continue stirring for 15 min and stop stirring. The solution is cooled to room temperature. The resulting orange-red liquid is a solution of gold nanoparticles.

[0077] In the process of preparing gold nanoparticles, sodium citrate (Na3C6H5O7·2H2O) solution needs to be quickly added to chloroauric acid (HAuCl4·4H2O) solution, and the color of the solution gradually changes from light yellow to orange-red. When the size of gold nanoparticle 2 is less than 20nm, the solution appears orange-red; when the size is between 20-70nm, the solution appears red; when the size is between 70-90nm, the solution appears wine red; when the size is greater than 90nm, the solution appears purple; and when the small-sized gold nanoparticles are severely aggregated, the solution appears blue; the particle size of the gold nanoparticles prepared in the solution can be observed to be 18nm by transmission scanning electron microscopy;

[0078] According to the relationship between the size of the nanoparticles and the color of the solution, during the experiment, if the sodium citrate (Na3C6H5O7·2H2O) solution is not added quickly enough, the gold nanoparticle solution can be observed to first turn light blue and then slowly turn red. This is mainly because when the sodium citrate (Na3C6H5O7·2H2O) solution is added too slowly, the gold nanoparticles are gradually reduced, and the earliest generated gold element will continue to grow as a crystal nucleus, resulting in a larger size of the prepared gold nanoparticles, so the observed solution appears blue. As the sodium citrate ( With the continued addition of sodium citrate (Na3C6H5O7·2H2O) solution, the number of small-sized gold nanoparticles increased, and the blue color in the solution was gradually covered by red. Although the final gold nanoparticle solution still appeared red, the slow addition of sodium citrate (Na3C6H5O7·2H2O) solution would lead to uneven size of the obtained gold nanoparticles. Therefore, during the experiment, all the sodium citrate (Na3C6H5O7·2H2O) solution should be quickly added to the chloroauric acid (HAuCl4·4H2O) solution to obtain a gold nanoparticle solution of uniform size.

[0079] S3. Preparation of masterbatch of quantum dot light-converting agricultural film middle layer: copper indium sulfur quantum dots 1 and polyethylene material 3 are mixed evenly in a mass ratio of 1:20, added into the extruder feed funnel, and the temperature is heated to 160° C. The mixed material is extruded by a twin-screw extruder at a speed of 500 r / min, and then cooled and granulated to finally obtain the masterbatch of quantum dot light-converting agricultural film middle layer;

[0080] S4. Preparation of masterbatch of nanoparticle protective film: After uniformly mixing gold nanoparticles 2 and polyethylene material 3 in a mass ratio of 1:80, add them into the extruder feed funnel and heat the temperature to 160°C. The mixed material is extruded through a twin-screw extruder at a speed of 500r / min and then cooled and granulated to finally obtain the masterbatch of nanoparticle protective film.

[0081] S5. Add the masterbatch of the middle layer of the quantum dot light-converting agricultural film into the mixed solution of vinyl bisstearamide, polyethylene material and anti-ultraviolet agent benzophenone, mix thoroughly, add to the mixer and continue stirring at a stirring speed of 1500r / min for 30 minutes; after stirring evenly, the middle layer mixed liquid is obtained, and added to the material trough of the film blowing machine and wait for film blowing; the melt index of the polyethylene material is 25g / 10min; the mass ratio of the masterbatch of the middle layer of the quantum dot light-converting agricultural film, vinyl bisstearamide, polyethylene material and anti-ultraviolet agent benzophenone is 10:5:100:1.

[0082] S6. Add the masterbatch of nanoparticle protective film to the mixed solution of vinyl bisstearamide, polyethylene material and anti-ultraviolet agent benzophenone, mix thoroughly, add to the mixer and continue stirring at a stirring speed of 1000r / min for 50 minutes, and obtain the protective layer mixed solution after uniform stirring. Add it to the material trough of the film blowing machine and wait for film blowing; the melt index of the polyethylene material is 25g / 10min; the mass ratio of the masterbatch of nanoparticle protective film, vinyl bisstearamide, polyethylene material and anti-ultraviolet agent benzophenone is 8:4:120:1.

[0083] S7. Set the die temperature of the film blowing machine to 160°C and the melting temperature to 180°C. The middle nozzle of the film blowing machine blows the middle layer mixed liquid to obtain the quantum dot middle film layer 5. The nozzles on both sides of the film blowing machine blow the protective layer mixed liquid to obtain the first nanoparticle protective film 4 and the second nanoparticle protective film 6. Finally, a three-layer film structure of quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas is obtained. After measurement, the thickness of the quantum dot light-converting agricultural film is 1.8mm.

[0084] Figure 3 A schematic diagram showing temperature changes of the quantum dot light-converting agricultural film prepared by the present invention compared with the common film in the prior art under the same lighting environment is shown; it can be seen from the figure that (during the entire low temperature period from November to April, under the same lighting environment, the average temperature of the quantum dot light-converting agricultural film prepared by the present invention is higher than that of the common film, which can alleviate the impact of low temperature on crops).

[0085] In the quantum dot light-conversion agricultural film prepared by the present invention, the quantum dot material should have strong absorption in the ultraviolet light, blue light and yellow light bands, and be able to efficiently convert them into the red light band required for crop photosynthesis; when natural light irradiates the metal nanoparticles, the metal nanoparticles are irradiated with a frequency consistent with the electrons on their surface, which will cause resonance of the electrons on the particle surface and form hot electrons; these hot electrons will decay through radiation diffusion or electron coupling; the electron coupling decay will redistribute the energy of the overheated electrons, thereby increasing the local surface temperature of the metal nanoparticles, realizing light-to-heat conversion on the surface of the quantum dot light-conversion agricultural film, accelerating the evaporation of condensed water on the surface of the light-conversion agricultural film, and achieving the purpose of extending the service life of the quantum dot light-conversion agricultural film.

[0086] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0087] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Quantum dot light conversion agricultural film suitable for high-cold and high-humidity areas, characterized by: It includes three structural functional layers stacked in sequence from top to bottom: a first nanoparticle protection film, a quantum dot intermediate film layer, and a second nanoparticle protection film; The quantum dot intermediate film layer is prepared by mixing quantum dot material, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film; the first nanoparticle protective film and the second nanoparticle protective film have the same structure, and are both prepared by mixing metal nanoparticles, polymer material, lubricant and anti-ultraviolet agent and then co-extruding and blowing film; The quantum dot material is copper indium sulfide quantum dots; the copper indium sulfide quantum dots have a double shell layer structure, the first shell layer is zinc sulfide as the shell, and the second shell layer is formed by injecting a mixed solution of zinc source, mercaptan and octadecene into the first shell layer synthesis solution to form the quantum dot material; The polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the lubricant is vinyl bisstearamide; the anti-ultraviolet agent is benzophenone; and the metal nanoparticles are gold nanoparticles or silver nanoparticles; The mass ratio of the quantum dot material to the polymer material is 1:5-40; the mass ratio of the metal nanoparticles to the polymer material is 1:40-100; The preparation method of copper indium sulfide quantum dots specifically comprises the following steps: S101. 0.125 mmol copper iodide, 0.5 mmol indium acetate, 2 mmol dodecyl mercaptan and 15 mmol oleylamine were injected into a three-necked flask to prepare a mixed reagent A solution; the mixed reagent A solution was degassed at 120° C. for 15 min and purged with nitrogen for 15 min to exclude oxygen; S102. 3 mmol of sulfur powder was fully dissolved in 9 mmol of octadecene and injected into the mixed reagent A solution at 250° C. to prepare a copper indium sulfur quantum dot synthesis solution; S103. Prepare the first shell layer synthesis solution of copper indium sulfide quantum dots: 5.3mmol zinc acetate dihydrate, 16.8mmol oleic acid and 8.3mmol octadecene are slowly injected into the above copper indium sulfide quantum dot synthesis solution at a rate of 2.0ml / min; after fully reacting for 30min, the first shell layer is gradually formed on the surface of the copper indium sulfide quantum dots to obtain the first shell layer synthesis solution of copper indium sulfide quantum dots; S104. Prepare the double shell layer synthesis solution of copper indium sulfide quantum dots: 5.3mmol zinc stearate, 11.1mmol dodecyl mercaptan and 16.7mmol octadecene are slowly injected into the first shell layer synthesis solution of copper indium sulfide quantum dots at a rate of 2.0ml / min respectively. After it is fully reacted for 2h, a second shell layer is gradually formed on the surface of the first shell layer of the quantum dots, forming a double-layer molecular coating structure.

2. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to claim 1 is characterized by: The thickness of the quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas is 1-2 mm.

3. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to any one of claims 1-2, characterized in that: Prepared by the following method: S1. Preparation of quantum dots by hot injection method; S2. Preparation of metal nanoparticles by chemical reduction method; S3. Preparation of masterbatch of quantum dot light-converting agricultural film intermediate layer: After the quantum dots and polyethylene material are uniformly mixed in proportion, the masterbatch of quantum dot light-converting agricultural film intermediate layer is prepared by extrusion granulation method; S4. Preparation of a masterbatch of a nanoparticle protective film: After the metal nanoparticles and the polyethylene material are uniformly mixed in proportion, a masterbatch of a nanoparticle protective film is prepared by extrusion granulation; S5. Add the masterbatch of the quantum dot light-converting agricultural film middle layer to the mixed solution of the polymer material, lubricant and anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 1300~2000r / min for 20~40min; after stirring evenly, the middle layer mixed solution is obtained, and added to the material tank of the film blowing machine to wait for film blowing; S6. Add the masterbatch of the nanoparticle protective film to the mixed solution of the polymer material, the lubricant and the anti-ultraviolet agent and mix them thoroughly, and continue stirring at a stirring speed of 800-1500 r / min for 40-60 min; after stirring evenly, the protective layer mixture is obtained, and added to the material tank of the film blowing machine to wait for film blowing; S7. Set the die head temperature of the film blowing machine to 150-170°C and the melting temperature to 175-185°C, and use the middle nozzle of the film blowing machine to blow the middle layer mixture to obtain a quantum dot middle film layer; use the nozzles on both sides of the film blowing machine to blow the protective layer mixture to obtain a first nanoparticle protective film and a second nanoparticle protective film; and finally obtain a three-layer film structure of a quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas.

4. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to claim 3 is characterized by: The parameters of the extrusion granulation in steps S3 and S4 are as follows: heating temperature 150-200° C., extrusion speed 300-800 r / min.

5. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to claim 4 is characterized by: The metal nanoparticles are gold nanoparticles; the step S2 specifically includes the following sub-steps: S201. Prepare chloroauric acid solution as a reaction material and sodium citrate solution as a reducing agent; S202. The chloroauric acid solution is heated to 70-80° C. while stirring at a speed of 500-800 r / min, and the sodium citrate solution is quickly added to turn the solution orange-red; S203. Continue heating and reflux for 8 to 15 minutes under vigorous stirring; stop heating, remove the heat source, continue stirring for 13 to 20 minutes and then stop stirring; cool the solution to room temperature to obtain a solution containing nano-gold particles.

6. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to claim 5, characterized in that: The polymer material is polyethylene material; the lubricant is vinyl bisstearamide; and the anti-ultraviolet agent is benzophenone.

7. The quantum dot light-converting agricultural film suitable for high-cold and high-humidity areas according to claim 6, characterized in that: The mass ratio of the masterbatch of the quantum dot light-converting agricultural film middle layer, the vinyl bisstearamide, the polyethylene material and the benzophenone is 10:5:100:1; the mass ratio of the masterbatch of the nanoparticle protective film, the vinyl bisstearamide, the polyethylene material and the benzophenone is 8:4:120:1.

Images