Quantum dot homoresonance effect agricultural fresh-keeping material and preparation method thereof

Abstract

The application discloses a kind of quantum dot same frequency resonance effect agricultural fresh-keeping material and preparation method thereof, belong to the field of agricultural protection technology.The fresh-keeping material includes substrate layer, intermediate reinforcing layer and quantum dot-magnetic-metal composite functional coating;Functional coating contains first, second functional sub-coating with spacing of 50-1000nm, which are composed of mineral base nano quantum dot doped with Zn element, Fe3O4@SiO2 core-shell structure magnetic component, microcapsule wrapped nano silver / copper biological metal antibacterial component and negative oxygen ion release component modified by silane coupling agent surface.The double coating same frequency resonance effect and multi-component synergistic effect realize harmful light filtering, active bacteriostatic disease prevention and crop health monitoring;Negative oxygen ion continuously releases 800-2000 / cm³, and optimizes greenhouse growth environment.Compared with traditional greenhouse film, pesticide usage is reduced by more than 40%, crop disease incidence is reduced by more than 35%, yield is increased by 15%-20%, and fruit vitamin, sugar and other nutrients and taste are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of agricultural protection technology, specifically relating to an agricultural preservation material with quantum dot resonance effect and its preparation method, which is particularly suitable for agricultural greenhouse covering scenarios, and can be used to optimize the crop growth environment, reduce pesticide use, and improve yield and quality. Background Technology

[0002] Agricultural greenhouse film is the most widely used agricultural covering material in facility agriculture. Its basic functions are heat preservation, light transmission, and blocking of adverse external environments. Traditional greenhouse films are mostly passive protection types, mainly improving film performance by adding functional additives such as ultraviolet absorbers and anti-fogging agents. However, their functions are relatively limited and they cannot actively inhibit the growth of harmful microorganisms inside the greenhouse. The control of fungal diseases such as gray mold, downy mildew, and powdery mildew, as well as bacterial soft rot, still mainly relies on chemical pesticide spraying. This not only increases planting costs but also leads to pesticide residue problems, affecting the green and safe quality of crops.

[0003] In recent years, quantum dot materials have shown application potential in the field of light-conversion agricultural films due to their unique optical properties, while magnetic nanomaterials can generate weak magnetic fields that influence plant growth and metabolism. However, the agricultural efficiency enhancement effects of using quantum dots or magnetic materials alone are still relatively limited, and there are no reported technical solutions for synergistically applying quantum dots, magnetic materials, bio-metallic antibacterial components, and negative oxygen ion releasing components to agricultural greenhouse films. Furthermore, there are no publicly available technologies utilizing a quantum dot-magnetic synergistic resonance process to produce agricultural greenhouse films. Traditional agricultural preservation materials cannot further improve crop yield, nutritional content, and taste by optimizing the growth environment, making it difficult to meet the comprehensive demands of modern large-scale agricultural planting for high yield, high quality, and environmental friendliness. Summary of the Invention

[0004] The technical problem this invention aims to solve is to address the shortcomings of traditional agricultural greenhouse films, such as limited functionality, poor antibacterial and protective effects, reliance on chemical agents, and inability to further improve crop yield and quality through optimized growth environment. This invention provides an agricultural greenhouse film based on the quantum dot-magnetic synergistic resonance effect and its preparation method. By constructing a multi-synergistic system of "physical filtration + chemical disinfection + biological promotion," it achieves harmful light filtration, active antibacterial and disease prevention, optimized growth environment, and crop health monitoring. Simultaneously, it continuously releases negative oxygen ions to optimize the greenhouse growth environment, increase the yield of crops and cash crops, enhance the nutritional content and taste of fruits and vegetables, and meet the needs of large-scale agricultural planting.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An agricultural preservation material with quantum dot resonance effect includes a substrate layer, an intermediate reinforcing layer composited on the outside of the substrate layer, and a quantum dot-magnetic-metal composite functional coating composited on the outside of the intermediate reinforcing layer. The functional coating comprises a first functional sub-coating and a second functional sub-coating, with a spacing of 50–1000 nm between them. Both are composed of doped modified mineral-based quantum dots, magnetic components, bio-metal nano-antibacterial components, and negative oxygen ion releasing components, which are in situ coated with a silane coupling agent. The two sets of quantum dot materials have the same composition and microstructure, which can induce a reinforced resonance effect. At the same time, the negative oxygen ion releasing components work together to continuously release negative oxygen ions, optimizing the microenvironment for crop growth in the greenhouse.

[0006] Furthermore, the doped modified mineral-based quantum dots are mineral-based quantum dots doped with Zn, with a particle size of 5-20 nm, and emit electromagnetic waves with a frequency of 0.5-10 GHz. They can selectively filter light that is harmful to crops and selectively retain visible light that is beneficial to photosynthesis.

[0007] Furthermore, the magnetic component is biocompatible Fe3O4@SiO2 core-shell structured magnetic nanoparticles with a particle size of 10-50 nm, accounting for 3%-8% of the total solid mass of the functional coating, and generating a weak magnetic field of 0.05-0.5 mT.

[0008] Furthermore, the bio-metal nano-antibacterial component is nano-silver and / or nano-copper, and the release rate is controlled by microencapsulation technology, accounting for 1% to 6% of the total solids of the functional coating.

[0009] Furthermore, the negative oxygen ion releasing component is a composite self-polarizing negative ion releasing system. The polarization ability of a single tourmaline mineral is limited and easily affected by environmental humidity. To adapt to the complex and variable environment of agricultural greenhouses (high humidity, temperature fluctuations, long-term outdoor use), this invention preferably employs a composite system synergistically modified with rare earth doping / composite carrier / electron promoter. Typical, but not limiting, examples include: (1) Ferroelectric stone-diatomite-cerium dioxide-lanthanum oxide-nanogermanium system: Ferroelectric stone 61-65 parts, diatomite 28-32 parts, CeO2 2-4 parts, La2O3 2-4 parts, nanogermanium 2-3 parts. The intrinsic polarization of ferroelectric stone and the introduction of oxygen vacancies through Ce / La dual rare earth doping enhance the polarization electric field. Diatomite acts as a natural porous carrier to regulate microenvironment moisture, and nanogermanium optimizes the proportion of small-particle negative ions. Under standard test conditions (25℃, 50%RH), this system can stably release a negative ion concentration ≥1500 ions / cm³, and exhibits good compatibility with water-based coatings, with a coating retention rate ≥93%.

[0010] (2) Ferro-tourmaline-montmorillonite-yttrium oxide-lanthanum oxide system: Ferro-tourmaline 62-68 parts, montmorillonite 24-28 parts, Y₂O₃ 4-5 parts, La₂O₃ 4-6 parts. Designed for high humidity environments (RH>75%), the interlayer structure of montmorillonite can lock in moisture and maintain the water molecule layer required for local ionization. Y / La co-doping stabilizes the lattice, and the negative ion release concentration can be further increased to ≥1700 ions / cm³ under high humidity conditions, making it suitable for rainy seasons in the south or high humidity greenhouses.

[0011] After surface modification with silane coupling agent KH560, the above composite system has a total particle size of 1-30 nm, accounting for 3%-8% of the total solid mass of the functional coating. Under the synergistic excitation of quantum dot resonance effect and weak magnetic field, it can continuously and stably release negative oxygen ions at a concentration of 1200-2000 ions / cm³ (the concentration of different ratio systems may vary slightly under standard test conditions, but all are within the protection scope of this invention).

[0012] Furthermore, the substrate layer is a PE or EVA film with a thickness of 30–50 μm; the intermediate reinforcing layer is a glass fiber mesh.

[0013] Furthermore, the components in the first and second functional sub-coatings achieve long-term sustained release of metal ions through in-situ encapsulation with the silane coupling agent and microcapsule encapsulation technology, ensuring the durability of the disinfection and antibacterial effects.

[0014] Furthermore, under the synergistic effect of the electromagnetic waves released by the quantum dots and the weak magnetic field generated by the magnetic components, the coupling field strength of the functional coating is increased to 5 to 10 times that of the single quantum dot system, while enhancing the anti-aging performance and antibacterial durability of the membrane.

[0015] Furthermore, the functional coating also includes anti-aging agents and light stabilizers to meet the long-term outdoor use requirements of greenhouse films and ensure the long-term stability of negative oxygen ion releasing components.

[0016] Furthermore, the agricultural preservation material can monitor the health status of crops in real time through changes in coupled signals, which facilitates agricultural managers to adjust planting management strategies in a timely manner and prevent the outbreak of pests and diseases in advance.

[0017] The present invention also provides a method for preparing the above-mentioned agricultural preservation material, comprising the following steps: (1) Mineral-based quantum dots doped with Zn were prepared by hydrothermal method. They were then mixed with Fe3O4@SiO2 core-shell magnetic particles, microencapsulated silver / copper nanoparticles, modified negative oxygen ion releasing components and silane coupling agent KH560, and in-situ coated composites were obtained by vacuum drying. (2) Disperse the composite powder in a film-forming aid, add an anti-aging agent and a light stabilizer, and prepare a coating slurry with a solid content of 5% to 8%; (3) Select a substrate layer, composite an intermediate reinforcing layer, and then perform plasma surface activation treatment; (4) The first functional sub-coating slurry and the second functional sub-coating slurry are sequentially coated on the pretreated intermediate reinforcing layer using a doctor blade coating process. The spacing between the two sub-coating layers is controlled to be 50-1000 nm. The coating is cured with hot air at 70-80°C and finally subjected to surface anti-fogging treatment to obtain the agricultural preservation material.

[0018] Preferably, the vacuum drying temperature in step (1) is 80-90°C and the time is 2-3 hours; the film-forming aid in step (2) is water-based acrylic resin; and the hot air curing time in step (4) is 20-30 minutes.

[0019] This invention also claims protection for the application of the agricultural preservation material in the covering of agricultural greenhouses.

[0020] The core synergistic mechanism of the agricultural preservation material described in this invention is as follows: quantum dots filter harmful light and retain beneficial light, providing suitable conditions for crop photosynthesis; magnetic components generate a weak magnetic field to regulate crop growth and metabolism; bio-metal ions achieve strong disinfection and antibacterial effects, reducing pests and diseases; negative oxygen ions purify greenhouse air, neutralize harmful gases, promote chlorophyll synthesis and root development in crops, and improve nutrient absorption efficiency; under the synergistic effect of these four components, the coupling field strength is increased to 5 to 10 times that of a single quantum dot system, while simultaneously enhancing the anti-aging properties of the membrane, the durability of disinfection and antibacterial effects, and the crop growth promotion effect, comprehensively helping to improve the quality and yield of crops.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) A triple synergistic maintenance system of "physical filtration + chemical disinfection + biological promotion" was constructed. Quantum dots doped with Zn have the function of regulating the light transmission spectrum, which can efficiently filter harmful ultraviolet rays and stray light to crops, and selectively retain visible light bands that are beneficial to crop photosynthesis, thus helping to improve the efficiency of crop photosynthesis. Nano-silver and nano-copper achieve long-term slow release through microencapsulation technology, which can specifically kill fungal diseases such as gray mold, downy mildew, and powdery mildew in greenhouses, as well as bacterial soft rot fungi, and strongly inhibit the growth of harmful microorganisms in greenhouses. The weak magnetic field generated by the magnetic components regulates crop growth and metabolism and promotes nutrient absorption.

[0022] (2) By setting two functional sub-coatings with a spacing of 50-1000nm and the same composition as the microstructure, the enhanced quantum dot resonance effect is triggered, which increases the coupling field strength to 5-10 times that of a single quantum dot system, greatly enhancing the harmful light filtering efficiency, antibacterial and sterilization ability and negative oxygen ion release rate, while enhancing the membrane's anti-aging performance and sterilization and antibacterial durability.

[0023] (3) The negative oxygen ion releasing component adopts a composite self-polarizing negative ion releasing system (such as a ferroelectric tourmaline-diatomite-cerium dioxide-lanthanum oxide-nano germanium system, or a ferroelectric tourmaline-montmorillonite-yttrium oxide-lanthanum oxide system) to replace single tourmaline powder. After surface modification with silane coupling agent KH560, under the continuous synergistic excitation of quantum dot resonance and weak magnetic field, it can stably release 1200-2000 negative oxygen ions / cm³ (the concentration of different formulation systems varies slightly under standard test conditions, all of which are within the protection scope of this invention). By selecting different composite systems, it can be applied to ordinary greenhouse environments and high-humidity agricultural areas (such as the rainy season in the south), respectively, to achieve stable and controllable release concentration. Negative oxygen ions can effectively purify the air inside greenhouses, neutralize harmful gases produced by soil and plant metabolism, and improve the microenvironment for crop growth. At the same time, they can promote chlorophyll synthesis in crops, enhance photosynthetic efficiency, promote root development and nutrient absorption, and significantly increase the yield of crops and cash crops. Compared with crops grown under traditional greenhouse film, the yield of crops can be increased by 15% to 20%, and the increase in the yield of cash crops is more obvious. In addition, negative oxygen ions can promote the synthesis and accumulation of nutrients such as vitamins, sugars, and minerals in crops, reduce nutrient loss, significantly improve the taste of fruits and vegetables, enhance the crispness, sweetness and flavor of fruits, and enhance the market competitiveness of products.

[0024] (4) The bio-metal components are encapsulated in microcapsules, which can achieve long-term slow release in outdoor high humidity and light environment, ensuring the durability of disinfection and antibacterial effect; the composite negative ion release system is surface modified and co-coordinated with anti-aging agents to achieve long-term stable release. With the addition of anti-aging agents and light stabilizers, the anti-aging performance of the membrane is further improved. The performance is stable in low temperature environment and is suitable for agricultural planting scenarios with different climates.

[0025] (5) Compared with traditional greenhouse films, the agricultural preservation material of the present invention can reduce the amount of pesticides used by more than 40% and reduce the incidence of crop diseases by more than 35%, significantly reducing planting costs, while avoiding pesticide residues and ensuring the green safety of crops; the preparation process can be continuously produced and can use biodegradable substrates, which meets the requirements of agricultural environmental protection, and ultimately helps to improve the yield and quality of crops, solving the core problems of traditional greenhouse films such as weak antibacterial and disinfection capabilities, reliance on pesticides, frequent crop diseases, low yield, and poor nutrition and taste. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. It should be noted that "parts" in the following embodiments refer to parts by mass, and percentages are mass percentages.

[0027] Example 1 (Preferred Example: Agricultural Greenhouse Film)

[0028] An agricultural preservation material with quantum dot resonance effect comprises, from the inside out, a substrate layer, an intermediate reinforcing layer, and a quantum dot-magnetic-metal composite functional coating. The functional coating includes a first functional sub-coating and a second functional sub-coating. Both sub-coatings have identical compositions, consisting of doped and modified mineral-based quantum dots, magnetic components, bio-metal nano-antibacterial components, and negative oxygen ion releasing components, in situ coated with a silane coupling agent KH560. The spacing between the first and second functional sub-coatings is precisely controlled at (100±20) nm; this nanoscale gap ensures that a reinforced resonance effect can be generated between the quantum dots.

[0029] The material selection and parameters for each component are as follows: Doped and modified mineral-based quantum nanodots: Zn-doped quantum dots (Zn:ZnO, doping amount 3mol%) prepared by hydrothermal method, with an average particle size of 10nm and a characteristic electromagnetic wave emission frequency of 2.4GHz. They can selectively filter ultraviolet rays and some stray light that are harmful to crops, and selectively retain the 400-700nm photosynthetically effective radiation band.

[0030] Magnetic component: Biocompatible Fe3O4@SiO2 nanoparticles with a core-shell structure are selected. The average particle size of the Fe3O4 core is 20 nm, the thickness of the SiO2 shell is about 3 nm, and the overall particle size is about 26 nm. The shell protection can effectively prevent the magnetic core from oxidizing and extend the service life outdoors. This component accounts for 5% of the total solids of the single-layer functional coating and generates a weak magnetic field of about 0.15 mT in the coating.

[0031] Bio-metal nano-antibacterial component: A mixture of nano-silver and nano-copper (mass ratio 1:1), with an average particle size of 8 nm, is selected. It is pre-encapsulated using melamine-formaldehyde resin microcapsule technology, with the microcapsule wall material accounting for 20% of the total mass of the metal particles. The sustained-release half-life is designed to be 45 days. The total mass of the antibacterial component accounts for 3% of the total solids mass of the functional coating.

[0032] Negative oxygen ion releasing components: A composite system of ferroelectric tourmaline-diatomaceous earth-cerium dioxide-lanthanum oxide-nano germanium was selected. Specifically, by mass fraction: ferroelectric tourmaline 61.8 parts, diatomaceous earth 29.8 parts, CeO2 2.9 parts, La2O3 2.9 parts, and nano germanium 2.6 parts. The composite powder was prepared through the following steps: ① Ferroelectric tourmaline and diatomaceous earth were air-jet milled to D50 of 25 nm and 250 mesh, respectively; ② The above materials were ball-milled with CeO2, La2O3, and nano germanium in ethanol medium at high energy (3500 rpm, 2 h); ③ Vacuum drying at 60℃ for 8 h; ④ Ar atmospheric pressure plasma activation treatment for 15 min; ⑤ Finally, surface modification was performed with silane coupling agent KH560. The total mass of this composite system accounted for 5.5% of the total solid mass of the functional coating.

[0033] By mass percentage, the functional coating consists of 83.5% Zn-doped quantum dots, 5% Fe3O4@SiO2 magnetic particles, 1.5% microencapsulated silver nanoparticles, 1.5% microencapsulated copper nanoparticles, 5.5% of the above-mentioned composite negative ion system, and the balance being silane coupling agent KH560 crosslinking material.

[0034] Preparation method: (1) Preparation of doped quantum dots: Zinc acetate and zinc nitrate were used as zinc sources. The Zn doping amount was 3 mol% and the mixture was subjected to hydrothermal reaction at 200℃ for 10 h under alkaline conditions. After washing, centrifugation and freeze drying, Zn doped mineral-based nano-quantum dot powder was obtained.

[0035] (2) Preparation of Fe3O4@SiO2 core-shell magnetic particles: The sol-gel method was adopted, using commercially available Fe3O4 nanoparticles (20nm) as the core and tetraethyl orthosilicate as the silicon source. The reaction was carried out in an alkaline ethanol-water system at 40℃ for 6h. After magnetic separation, washing and drying, Fe3O4@SiO2 core-shell magnetic nanoparticles were obtained.

[0036] (3) Microcapsule encapsulation of bio-metal nanoparticles: Nano-silver and nano-copper powders were dispersed in melamine formaldehyde resin prepolymer solution, pH was adjusted to 4.5, and the mixture was stirred at 70°C for 3 hours to allow the resin to polymerize in situ on the surface of the metal particles to form microcapsule wall material. After centrifugation, washing and low-temperature drying, nano-silver and nano-copper powders encapsulated in microcapsules were obtained.

[0037] (4) Preparation of quantum dot-magnetic-metal composite powder: The doped quantum dots obtained in step (1), the Fe3O4@SiO2 magnetic particles obtained in step (2), the microencapsulated silver and copper nanoparticles obtained in step (3), and the composite negative ion powder prepared in step (5) are mixed in proportion, and silane coupling agent KH560 (accounting for 6% of the total mass of each component) is added. The mixture is stirred and reacted in an ethanol-water mixed solvent at 65°C for 5 hours to achieve in-situ coating and composite of the four components. After the reaction, the suspension is transferred to a vacuum drying oven and dried at 85°C and -0.1MPa vacuum for 3 hours to obtain the composite powder. The vacuum drying process can improve the powder dispersibility, anti-aging properties, and negative oxygen ion release stability.

[0038] (5) Preparation of composite negative ion powder: According to the proportions and processes of the negative ion releasing components mentioned above, prepare ferroelectric stone-diatomite-cerium dioxide-lanthanum oxide-nano germanium composite powder for later use.

[0039] (6) Preparation of functional coating slurry: The composite powder obtained in step (4) is slowly added to the water-based acrylic resin film-forming aid. At the same time, hindered amine light stabilizer (accounting for 1.5% of the total solids of the slurry) and benzotriazole ultraviolet absorber (accounting for 1.0% of the total solids of the slurry) are added as anti-aging agents. The mixture is dispersed at 1500r / min for 25min at high speed, and the viscosity is adjusted. Finally, a uniform coating slurry with a solid content of 6% is obtained.

[0040] (7) Pretreatment of substrate layer and composite of intermediate reinforcement layer: EVA (ethylene-vinyl acetate copolymer) film with a thickness of 40μm is selected as substrate layer. First, it is treated with corona (power density 150W·min / m²) to make the surface tension reach more than 42mN / m. Then, glass fiber mesh is composited on the outside of EVA film through hot pressing composite process (temperature 110℃, pressure 0.3MPa) as intermediate reinforcement layer. Finally, the surface of the reinforcement layer is subjected to air atmosphere plasma activation treatment with power 200W and treatment time 40s to reduce the surface water contact angle to below 25°.

[0041] (8) Coating Composite Molding: A doctor blade coating process was adopted. First, a first layer of functional coating slurry was coated on the surface of the pretreated intermediate reinforcing layer, and the wet film thickness was controlled to be 15 μm by the doctor blade gap. This coating was pre-cured in a 70℃ hot air oven for 8 min to form a semi-dry surface layer. Then, a second layer of functional coating slurry was coated on the pre-cured first coating with the same parameters. The doctor blade gap was precisely adjusted in real time by laser thickness measurement to ensure that the final gap between the two sub-coatings was precisely controlled at (100±20) nm. Finally, it was cured in an 80℃ hot air oven for 25 min to complete the cross-linking of the silane coupling agent.

[0042] (9) Surface anti-fogging treatment: Spray a layer of anti-fogging coating liquid (mainly composed of polyoxyethylene nonionic surfactant) on the outermost surface of the obtained film, dry at 60℃ for 5 minutes to form an anti-fogging layer, improve the light transmittance and practicality of the greenhouse film, and ensure the smooth release of negative oxygen ions to meet the needs of crop photosynthesis. Roll up to obtain a roll of agricultural greenhouse film.

[0043] Under standard test conditions (25℃, normal pressure, RH 50%), the concentration of negative ions released by the coating in this embodiment is stable in the range of 1520 to 1680 ions / cm³.

[0044] Example 2 (Verification example under parameter range, the negative ion component uses a simplified formula)

[0045] This embodiment is basically the same as Embodiment 1, except that: the negative oxygen ion releasing component adopts a simplified system of ferroelectric tourmaline-diatomite-lanthanum oxide (excluding CeO2 and nano-germanium), specifically 68 parts by mass of ferroelectric tourmaline, 28 parts by mass of diatomite, and 4 parts by mass of La2O3; the Zn-doped quantum dots have a particle size of 5 nm and a release frequency of 0.5 GHz; the Fe3O4@SiO2 magnetic particles have a particle size of 10 nm, accounting for 3% of the coating mass, generating a weak magnetic field of approximately 0.05 mT; the microencapsulated nano-silver particles have a particle size of 4 nm, accounting for 1% of the coating mass; the above simplified negative ion system accounts for 3% of the coating mass; the spacing between the two sub-coating layers is controlled at (55±5) nm; the substrate layer is a PE film with a thickness of 30 μm; and the coating slurry has a solid content of 5%. The curing conditions are hot air curing at 70℃ for 30 min. Under standard test conditions, this simplified formula releases a negative ion concentration of 820–900 ions / cm³.

[0046] Example 3 (Parameter range verification example, negative ion component adopts highly doped and high humidity system)

[0047] This embodiment is basically the same as Embodiment 1, except that the negative oxygen ion releasing component is replaced with a composite system of ferroelectric tourmaline-montmorillonite-yttrium oxide-lanthanum oxide, with the following proportions: 64.8 parts ferroelectric tourmaline, 25.7 parts montmorillonite, 4.5 parts Y2O3, and 5.0 parts La2O3. The preparation process is adjusted to high-energy ball milling with ethanol at 3700 rpm for 2.5 h, vacuum freeze-drying at -45℃ for 10 h, and nitrogen annealing at 345℃ for 1.8 h. This composite system accounts for 7% of the total solid mass of the coating; the Zn-doped quantum dots have a particle size of 20 nm and a release frequency of 10 GHz; the Fe3O4@SiO2 magnetic particles have a particle size of 50 nm, accounting for 8% of the coating mass, generating a weak magnetic field of about 0.5 mT; the microencapsulated nano-silver and nano-copper mixture has a particle size of 10 nm and accounts for 6% of the total mass of the coating; the substrate layer is a 50 μm thick EVA film; and the coating slurry has a solid content of 8%. The curing conditions are hot air curing at 80℃ for 20 min. Under standard testing conditions, the concentration of negative ions released is 1880–1980 ions / cm³.

[0048] Example 4 (Application of biodegradable substrate)

[0049] This embodiment is basically the same as Embodiment 1, except that a 40μm thick biodegradable PLA / PBAT blend film is used as the substrate layer, and natural hemp fiber mesh is used instead of glass fiber mesh in the intermediate reinforcing layer to meet the environmentally friendly and biodegradable requirements of specific agricultural scenarios. The negative ion component is the same as in Embodiment 1. The remaining components, proportions, and coating and curing processes are completely consistent with those in Embodiment 1.

[0050] Example 5 (Pure silver ion antibacterial example)

[0051] This embodiment is basically the same as Embodiment 1, except that the bio-metal nano-antibacterial component uses only microcapsule-encapsulated silver nanoparticles, without the addition of copper nanoparticles. The silver nanoparticles account for 4% of the total solid mass of the coating, and the corresponding quantum dot proportion is adjusted to 83%. The negative ion component is the same as in Embodiment 1. This is used to demonstrate the agricultural application effect of this invention when silver is used as the sole bio-metal slow-release bactericidal component.

[0052] Example 6 (Formula for high humidity areas)

[0053] This embodiment is basically the same as Example 1, except that the negative oxygen ion releasing component is replaced with a composite system of ferroelectric tourmaline-montmorillonite-yttrium oxide-lanthanum oxide, with the following proportions: 64.8 parts ferroelectric tourmaline, 25.7 parts montmorillonite, 4.5 parts Y₂O₃, and 5.0 parts La₂O₃. The preparation process is adjusted to high-energy ball milling with ethanol at 3700 rpm for 2.5 h, vacuum freeze-drying at -45℃ for 10 h, and nitrogen annealing at 345℃ for 1.8 h. This composite system accounts for 6.0% of the total solids content of the coating. The rest is the same as in Example 1.

[0054] Tested under simulated high humidity conditions (30℃, RH 85%), the coating released a negative ion concentration of 1750–1920 ions / cm³; under normal conditions (25℃, RH 50%), it maintained a concentration of ≥1400 ions / cm³. This embodiment is particularly suitable for use in spring and summer in southern my country or in greenhouses for aquatic crops.

[0055] Comparative Example 1 (Single-layer coating comparison)

[0056] An agricultural greenhouse film, unlike Example 1, does not construct a double-layer functional sub-coating; instead, it only coats a single-layer functional coating with the same composition and total thickness as in Example 1 on the intermediate reinforcing layer. All other materials and preparation processes are identical. This is used to verify the contribution of the interlayer co-frequency resonant structure of the two quantum dots to the enhancement of the coupling field and overall performance.

[0057] Comparative Example 2 (Comparison without biometallic components)

[0058] An agricultural greenhouse film, unlike Example 1, completely removes the bio-metal nano-antibacterial components (microencapsulated nano-silver and nano-copper) in the composite powder preparation step, while all other components, proportions (appropriately supplemented with quantum dots), and preparation processes remain completely unchanged. This is used to verify the necessity of the bio-metal ion disinfection and antibacterial defense line in a synergistic system.

[0059] Comparative Example 3 (Comparison of Components Without Negative Oxygen Ions)

[0060] An agricultural greenhouse film, unlike Example 1, completely removes the negative oxygen ion releasing component (modified tourmaline powder) in the composite powder preparation step, while all other components, proportions (appropriately supplemented with quantum dots), and preparation processes remain completely unchanged. It is used to independently evaluate the contribution of negative oxygen ions in optimizing the greenhouse microenvironment, promoting crop growth, and improving quality.

[0061] Comparative Example 4 (Traditional commercially available greenhouse film)

[0062] A commercially available brand of ordinary EVA agricultural greenhouse film, 40μm thick, contains conventional ultraviolet absorbers and anti-fogging agents, but does not contain functional components such as quantum dots, magnetic materials, bio-metal antibacterial agents, or negative oxygen ion release agents.

[0063] Application examples and performance verification

[0064] To fully verify the effectiveness of the present invention in actual agricultural greenhouse applications, the following series of performance tests and application experiments were conducted on the above embodiments and comparative examples.

[0065] 1. Harmful light filtering and photosynthetically active radiation transmittance test

[0066] The spectral transmittance of each sample in the 280–800 nm wavelength range was measured using a UV-Vis-NIR spectrophotometer (integrating sphere attachment). Special attention was paid to the blocking rate in the 280–380 nm harmful ultraviolet band and the transmittance in the 400–700 nm photosynthetically active radiation (PAR) band. The test results are shown in Table 1.

[0067] Table 1. Spectral transmittance performance test results

[0068] As shown in Table 1, Examples 1-6 can effectively filter harmful ultraviolet rays while maintaining a high level of PAR transmittance, and their PAR selectivity ratios are significantly higher than those of the conventional greenhouse film in Comparative Example 4. The PAR selectivity ratios of Examples 1 and 6 both exceed 10, indicating that the dual quantum dot resonant structure has excellent wavelength selective modulation capabilities.

[0069] 2. Test on the antibacterial and disease control effects in the greenhouse

[0070] Seven identical simulated greenhouses (6m × 4m × 2.5m) were used, with greenhouse films from Examples 1, 3, 6, 2, 3, and 4 applied for coverage. Each greenhouse housed 50 cucumber and 50 tomato plants, and the experiment lasted for a complete 90-day growth cycle. No fungicides were sprayed during the experiment. The number of fungal spores in the air and the occurrence of plant diseases were monitored regularly. The results are shown in Table 2.

[0071] Table 2. Disease control effects in simulated greenhouses

[0072] The results confirmed that, under conditions without the use of any fungicides, Examples 1, 3, and 6 reduced the disease incidence rate by more than 35% compared to traditional greenhouse films (Comparative Example 4), and reduced pesticide usage by more than 40% (effectively 100% fungicide-free), fully meeting the standards for green agricultural planting. Comparative Example 2, lacking bio-metal ion disinfection components, had a disease incidence rate even higher than that of traditional films, fully demonstrating the crucial role of the sustained sterilization effect of microcapsule-released metal ions.

[0073] 3. Experiment on the impact of crop yield and quality

[0074] In the simulated greenhouse experiment described above, the total yield of cucumbers and tomatoes was recorded at harvest time, and samples were taken to test the vitamin C content, soluble sugar content, and sensory evaluation of the fruits. The yield was normalized using the traditional film control group 4 as a baseline (100%). The results are shown in Tables 3 and 4.

[0075] Table 3 Cucumber Yield and Quality

[0076] Table 4 Tomato Yield and Quality

[0077] As shown in Tables 3 and 4, the relative yields of cucumbers and tomatoes in Examples 1, 3, and 6 all increased by more than 15% (maximum 19.1% for cucumbers and 20.2% for tomatoes), verifying the beneficial effect of "increasing crop yields by 15%–20% compared to traditional greenhouse film cultivation." The vitamin C and soluble sugar content in the fruits were also significantly higher than those grown under traditional film, and the sensory evaluation scores were significantly superior. Comparative Example 3, lacking negative oxygen ion components, showed a significantly weaker effect in improving yield and quality, strongly demonstrating the crucial role of negative oxygen ions in promoting crop photosynthesis, nutrient absorption, and nutrient accumulation.

[0078] 4. Negative oxygen ion release test

[0079] Each sample was cut into 1m×1m pieces and placed in a 20m³ sealed test chamber at 25℃ and 50% relative humidity for 24 hours. The concentration of negative oxygen ions in the chamber was measured using an atmospheric negative ion concentration meter. The results are as follows: Example 1 (Ferro-tourmaline-diatomite-Ce / La-germanium system): 1580-1660 particles / cm³ Example 2 (Simplified Ferro-Tourmaline-Diatomite-La System): 820-900 particles / cm³ Example 3 (Highly doped iron tourmaline-montmorillonite-Y / La system): 1880-1980 particles / cm³ Example 5 (same negative ion system as Example 1): 1550-1620 ions / cm³ Example 6 (High humidity optimized system, 30℃, RH 85%): 1750~1920 cells / cm³ All examples containing negative ion components released concentrations ranging from 820 to 1980 ions / cm³ under standard operating conditions, and controllable release within the range of 800 to 2000 ions / cm³ could be achieved through formulation adjustments. Comparative Examples 3 and 4 showed almost no detectable negative oxygen ions. Long-term follow-up tests indicated that after simulated outdoor aging (1000 hours of accelerated aging under xenon lamp), the release concentrations of Examples 1 and 6 remained above 80% of their initial values, confirming that the composite negative ion system synergistically ensured long-term stability with the anti-aging agent.

[0080] 5. Demonstration of Crop Health Status Monitoring

[0081] In the simulated greenhouse covered by Example 1, the fluorescence spectrum of specific areas of the greenhouse film was periodically scanned using a portable spectrometer. The results showed that when crops were growing healthily, the fluorescence signal of the functional coating maintained a stable fluorescence peak in the green wavelength region. When crops were subjected to pest and disease stress, changes in metabolites were transmitted to the coating through the microenvironment, causing changes in the coupled field signal, and the position of the main fluorescence peak gradually shifted towards the orange-red wavelength region. Agricultural managers can monitor the health status of crops in real time based on this visualized change in the coupled signal, adjust planting management strategies in a timely manner, prevent outbreaks of pests and diseases in advance, and achieve precision agricultural management.

[0082] 6. Membrane anti-aging performance test

[0083] Accelerated aging tests were conducted using xenon lamps according to GB / T 16422.2 standard. The tensile strength retention and elongation at break retention rates of each sample were tested after 1000h and 2000h of aging. Examples 1, 3, and 6 all achieved tensile strength retention rates of over 80% after 2000h aging (Example 1: 82%, Example 6: 81%), significantly better than the 65% of Comparative Example 4. This demonstrates that the present invention, through the introduction of anti-aging agents, light stabilizers, and the synergistic effect between components, effectively enhances the anti-aging performance of the membrane, meeting the requirements for long-term outdoor use.

[0084] 7. Safety and Environmental Impact Assessment

[0085] According to third-party testing, under simulated rainwater leaching conditions, the migration of heavy metals such as silver and copper in Examples 1 and 6 was far below the limits of the "Ecological Indicators of Arsenic, Cadmium, Lead, Chromium and Mercury in Fertilizers" and the standard limits of farmland irrigation water quality; the membrane can be recycled or safely landfilled after use; Example 4 uses a biodegradable substrate, which meets the requirements of agricultural environmental protection.

[0086] In summary, the agricultural preservation material of this invention, through its unique dual-quantum dot resonance coating structure and multi-component synergistic mechanism, achieves integrated functions of harmful light filtration, active antibacterial and disease prevention, growth environment optimization, and crop health monitoring. This significantly reduces pesticide use, decreases crop disease incidence, and effectively improves crop yield, nutritional content, and taste of fruits and vegetables. Furthermore, the film exhibits good durability, is safe and environmentally friendly, and can be widely applied to various agricultural greenhouses, possessing significant promotional and application value. The above description is merely a preferred embodiment of this invention and does not limit the scope of protection of this invention. Any equivalent substitutions or simple modifications made based on the technical concept of this invention, as long as they achieve the functions of quantum dot-magnetic resonance, harmful light filtration, bio-metal-negative oxygen ion synergistic protection, and crop quality improvement, should be included within the scope of protection of this invention.

Claims

1. An agricultural preservation material with quantum dot resonance effect, characterized in that, It includes a substrate layer, an intermediate reinforcement layer composited on the outside of the substrate layer, and a quantum dot-magnetic-metal composite functional coating composited on the outside of the intermediate reinforcement layer; The functional coating comprises a first functional sub-coating and a second functional sub-coating, with a spacing of 50 to 1000 nm between them. Both are composed of doped modified mineral-based quantum dots, magnetic components, bio-metal nano-antibacterial components, and negative oxygen ion releasing components, which are in situ coated with a silane coupling agent. The two sets of quantum dot materials have the same composition and microstructure to induce an enhanced resonance effect.

2. The agricultural preservation material according to claim 1, characterized in that, The doped and modified mineral-based quantum dots are mineral-based quantum dots doped with Zn, with a particle size of 5-20 nm, and emit electromagnetic waves with a frequency of 0.5-10 GHz. They are used to filter out light that is harmful to crops and selectively retain visible light that is beneficial to photosynthesis.

3. The agricultural preservation material according to claim 1, characterized in that, The magnetic component consists of Fe3O4@SiO2 core-shell magnetic nanoparticles with a particle size of 10–50 nm, accounting for 3%–8% of the total solid mass of the functional coating, and generating a weak magnetic field of 0.05–0.5 mT.

4. The agricultural preservation material according to claim 1, characterized in that, The bio-metal nano-antibacterial component is nano-silver and / or nano-copper, and the release rate is controlled by microencapsulation technology. Its mass accounts for 1% to 6% of the total solids of the functional coating.

5. The agricultural preservation material according to claim 1, characterized in that, The negative oxygen ion releasing component is a composite system of ferroelectric tourmaline-diatomite-cerium dioxide-lanthanum oxide-nano germanium, wherein ferroelectric tourmaline comprises 61-65 parts, diatomite comprises 28-32 parts, CeO2 comprises 2-4 parts, La2O3 comprises 2-4 parts, and nano germanium comprises 2-3 parts. It is surface modified with silane coupling agent KH560, and the total particle size is 1-30 nm, accounting for 3%-8% of the total solids of the functional coating. Under the synergistic excitation of the quantum dot resonance effect and the weak magnetic field, negative oxygen ions with a concentration of 1200-2000 per cm³ can be released continuously.

6. The agricultural preservation material according to claim 1, characterized in that, The negative oxygen ion releasing component is a composite system of ferroelectric tourmaline-montmorillonite-yttrium oxide-lanthanum oxide, wherein ferroelectric tourmaline comprises 62-68 parts, montmorillonite comprises 24-28 parts, Y2O3 comprises 4-5 parts, and La2O3 comprises 4-6 parts. It is surface modified with silane coupling agent KH560, and the total particle size is 1-30 nm, accounting for 3%-8% of the total solids of the functional coating. Under the synergistic excitation of the quantum dot resonance effect and the weak magnetic field, negative oxygen ions with a concentration of 1200-2000 per cm³ can be released continuously.

7. The agricultural preservation material according to claim 1, characterized in that, The substrate layer is a PE or EVA film with a thickness of 30-50 μm; the intermediate reinforcing layer is a glass fiber mesh.

8. The agricultural preservation material according to claim 1, characterized in that, The functional coating also contains anti-aging agents and light stabilizers to ensure the long-term stability of the negative oxygen ion releasing components; under the synergistic effect of the electromagnetic waves released by quantum dots and the weak magnetic field generated by magnetic components, the coupling field strength of the functional coating is increased to 5 to 10 times that of a single quantum dot system.

9. A method for preparing the agricultural preservative material according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Mineral-based quantum dots doped with Zn were prepared by hydrothermal method. They were then mixed with Fe3O4@SiO2 core-shell magnetic particles, microencapsulated silver and / or copper nanoparticles, negative oxygen ion releasing components modified with silane coupling agent KH560, and silane coupling agent. The mixture was then coated and composited in situ and dried under vacuum at 80-90℃ for 2-3 hours to obtain composite powder. (2) Disperse the composite powder in an aqueous acrylic resin film-forming aid, add an anti-aging agent and a light stabilizer, and prepare a coating slurry with a solid content of 5% to 8%; (3) Select a substrate layer, composite an intermediate reinforcing layer, and then perform plasma surface activation treatment; (4) The first functional sub-coating slurry and the second functional sub-coating slurry are sequentially coated on the pretreated intermediate reinforcing layer using a doctor blade coating process. The spacing between the two sub-coating layers is controlled to be 50-1000 nm. The coating is cured with hot air at 70-80°C for 20-30 min. Finally, the surface is treated with anti-fogging to obtain the agricultural preservation material.

10. The application of the agricultural preservation material according to any one of claims 1-8 in the covering of agricultural greenhouses.

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