Environmentally friendly coating for long-term inhibition of tobacco beetles and preparation method thereof

Abstract

The present invention relates to the technical field of coating materials, and in particular to an environmentally friendly coating for long-term inhibition of tobacco beetles and a preparation method thereof, comprising the following raw materials: modified Fe-MOG, Cr-ZnGa2O4 nanospheres, hydroxypropyl methylcellulose, polylactic acid, bentonite, menthol, eugenol, matrine and tea polyphenols. In the present invention, the modified Fe-MOG, Cr-ZnGa2O4 nanospheres and natural plant extracts form a composite controlled-release structure with moisture-heat adaptive closure and weak light-triggered release, synergistically achieving long-term inhibition of tobacco beetles and ensuring the morphological stability of the coating in a high-temperature and high-humidity environment. In a high-temperature and high-humidity environment, the pores of the modified Fe-MOG shrink, combining the hydrophobic phosphate groups on the surface and the dense structure of the Cr-ZnGa2O4 nanospheres to form a nano-barrier layer, which inhibits the rapid dissipation and thermal degradation of the active ingredients. The Cr-ZnGa2O4 nanospheres induce the modified Fe-MOG micro-pores to open and release the active ingredients by forming a micro-thermal stress zone, while achieving a non-chemical auxiliary insect inhibition effect.

Description

Technical Field

[0001] The invention relates to the technical field of coating materials, in particular to an environmentally friendly coating for inhibiting tobacco beetles in a long-term manner and a preparation method thereof. Background Art

[0002] The tobacco beetle is a widespread pest found in stored foods such as tobacco, spices, and dried fruits. Traditional control methods rely primarily on chemical insecticides. While effective in the short term, long-term use can negatively impact the environment and ecosystem due to environmental pollution and the development of insect resistance. Therefore, environmentally friendly coatings are emerging as a new solution for tobacco beetle control. By combining natural plant extracts, chemical inhibitors, and functional nanomaterials to form an effective protective layer, they not only reduce the use of insecticides but also avoid environmental pollution. Tobacco is often stored in high humidity and high temperature environments, which poses a significant challenge to the long-term stability of the coating. If the coating is unstable, resulting in premature release of active ingredients or coating flaking, its effectiveness against tobacco beetles will be severely compromised. Therefore, environmentally friendly coatings for long-term tobacco beetle control must not only possess long-lasting insecticidal and repellent properties but also maintain stability and functionality in harsh environments such as high humidity and high temperature. This ensures effective control of tobacco beetles while preserving storage quality and economic value. Summary of the Invention

[0003] (1) Technical problems to be solved

[0004] The purpose of the present invention is to provide an environmentally friendly coating for long-term inhibition of tobacco beetles and a preparation method thereof. By introducing natural plant extracts and combining them with modern nanotechnology, the coating can effectively and continuously inhibit the growth and reproduction of tobacco beetles without relying on large amounts of chemical pesticides. At the same time, the environmentally friendly coating can maintain good morphological stability and inhibitory effect under harsh environmental conditions such as high temperature and high humidity, thereby ensuring long-term effectiveness and reliability in practical applications.

[0005] (2) Technical solution

[0006] To achieve the above objectives, on the one hand, the present invention provides an environmentally friendly coating for long-term inhibition of tobacco beetles, comprising the following raw materials in parts by weight: 4-8 parts of Cr-ZnGa2O4 nanospheres, 8-12 parts of hydroxypropyl methylcellulose, 12-16 parts of polylactic acid, 8-10 parts of bentonite, 4-6 parts of menthol, 3-5 parts of eugenol, 3-5 parts of matrine, and 2-4 parts of tea polyphenols;

[0007] The environmentally friendly coating for long-term tobacco beetle inhibition also includes:

[0008] Modified Fe-MOG;

[0009] The modified Fe-MOG and Cr-ZnGa2O4 nanospheres are in a weight ratio of 12:(4-8);

[0010] The modified Fe-MOG is prepared by grafting phosphate groups on the surface of Fe-MOG. The particle size of the modified Fe-MOG is 95-115 nm and the specific surface area is 380-400 m 2 / g.

[0011] Furthermore, the preparation method of the modified Fe-MOG comprises:

[0012] S11. Under nitrogen protection and stirring, dissolve ferric chloride in a N,N-dimethylformamide / anhydrous ethanol mixed solvent, where the volume ratio of N,N-dimethylformamide to anhydrous ethanol in the mixed solvent is 1:2. After stirring at room temperature for 1-2 hours, add 1,3,5-benzenetricarboxylic acid, controlling the weight ratio of ferric chloride to 1,3,5-benzenetricarboxylic acid to be 1:0.5. Stirring is continued for 2-4 hours, and the pH value is adjusted to 3.8-4.2 with triethylamine. Simultaneously, the temperature is raised to 70-80°C, and the reaction is continued with stirring for 6-8 hours. Then, the mixture is allowed to stand and age for 12-14 hours to obtain a first mixed solution.

[0013] S12. The first mixed solution was subjected to high-speed centrifugation at a speed of 8000-10000 rpm for 5-10 min. The separated gel was washed three times with N,N-dimethylformamide and anhydrous ethanol alternately and then vacuum dried at a drying temperature of 55-65°C for 18-24 h to obtain Fe-MOG, which was ground into a powder and set aside.

[0014] S13. The Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated in a 9:1 volume ratio of anhydrous ethanol to purified water at a frequency of 40 to 50 kHz. After ultrasonic treatment for 15 to 20 minutes, dodecyl phosphate was added. Ultrasonic treatment was continued for 30 to 45 minutes, and the pH was adjusted to 4.8 to 5.2 with acetic acid to obtain a second mixed solution.

[0015] S14. The second mixed solution is transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a temperature of 85-105°C for 20-24 hours. The reaction is then followed by high-speed centrifugation at a speed of 10,000-12,000 rpm for 15-20 minutes. The separated solid is washed alternately with acetone and anhydrous ethanol three times and then vacuum dried at a temperature of 55-65°C for 18-24 hours to obtain the modified Fe-MOG, which is then ground into a powder for later use.

[0016] Furthermore, the weight ratio of Fe-MOG to dodecyl phosphate is 1:(0.4-0.6).

[0017] Furthermore, the preparation method of the Cr-ZnGa2O4 nanospheres includes:

[0018] S21. Prepare a mixed solvent of purified water and ethylene glycol in a volume ratio of 1:1 under stirring, dissolve zinc nitrate, gallium nitrate and chromium chloride in the mixed solvent, and control the Zn 2+ and Ga 3+ The molar ratio of 1:2 was 1:2, and the mixture was stirred for 2 to 4 hours to obtain a third mixed solution;

[0019] S22. Under stirring, trisodium citrate was added to the third mixed solution for complexation reaction, and stirring was continued for 1 to 2 hours, and then transferred to a polytetrafluoroethylene reactor for hydrothermal reaction at a reaction temperature of 160 to 180 ° C. After 12 to 14 hours, a fourth mixed solution was obtained;

[0020] S23. The fourth mixed solution was vacuum filtered, and the resulting precipitate was washed three times with purified water and anhydrous ethanol alternately, and then vacuum dried at a drying temperature of 55 to 65 ° C. After drying for 8 to 12 hours, the Cr-ZnGa2O4 precursor was obtained and ground into a powder for later use;

[0021] S24. Calcine the Cr-ZnGa2O4 precursor powder in a muffle furnace at a temperature of 800-900°C at a heating rate of 5°C / min for 4-6 h to obtain Cr-ZnGa2O4 nanospheres, which are then ground into a powder for later use.

[0022] Furthermore, the nanometer size of the Cr-ZnGa2O4 nanospheres is 120-150 nm, and the specific surface area is 35-65 m 2 / g.

[0023] Furthermore, the Cr doping amount in the Cr-ZnGa2O4 nanospheres is 0.5-1 mol%.

[0024] On the other hand, based on the same inventive concept, the present invention also provides a method for preparing an environmentally friendly coating for long-term tobacco beetle inhibition, which is applied to the environmentally friendly coating for long-term tobacco beetle inhibition, comprising the following steps:

[0025] S31. The modified Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated. The volume ratio of anhydrous ethanol to purified water in the mixed solvent was 1:1. The ultrasonic frequency was 40-50 kHz and the ultrasonic temperature was 55-65°C. After ultrasonic treatment for 15-20 min, Cr-ZnGa2O4 nanospheres, menthol, eugenol, matrine, and tea polyphenols were added in sequence and stirred at a high speed of 1000-1200 rpm and a stirring temperature of 75-85°C for 8-12 h to obtain a fifth mixed solution.

[0026] S32. Hydroxypropyl methylcellulose, polylactic acid and bentonite were sequentially added to the fifth mixed solution under stirring, with stirring at a temperature of 55 to 65 ° C. After stirring for 1 to 2 hours, ultrasonic treatment was performed at an ultrasonic frequency of 40 to 50 kHz for 4 to 6 hours to obtain the environmentally friendly coating solution;

[0027] S33. The environmentally friendly coating solution is evenly applied to the surface of the substrate by brushing. The coated substrate is dried at 50-70°C for 2-4 hours to obtain the long-lasting environmentally friendly coating for inhibiting tobacco beetles.

[0028] The mechanism of action of the above raw material components is as follows:

[0029] Menthol, eugenol, matrine, and tea polyphenols are all natural plant extracts. Menthol and eugenol have strong volatile odors that can disrupt the foraging and reproductive behavior of tobacco beetles, acting as a repellent. Matrine and tea polyphenols are toxic to the insect nervous system, affecting the beetle's physiological metabolism, affecting its growth and development, and reducing its reproductive capacity. By adding these natural plant extracts, the use of chemical pesticides can be reduced, avoiding the pollution and pest resistance problems caused by excessive chemical use.

[0030] Hydroxypropyl methylcellulose is a water-soluble polymer that forms a uniform, dense coating on the substrate surface, improving the adhesion of active ingredients to the substrate surface and ensuring stable release of active ingredients. It also absorbs small amounts of moisture from the air, preventing the coating from cracking due to excessive drying, thereby improving the coating's durability and service life. Polylactic acid is a biodegradable polymer that provides good mechanical strength, improving the coating's durability under external forces, enhancing the coating's structural stability, and preventing flaking. Bentonite is a layered silicate mineral that can improve the coating's moisture resistance, preventing component loss or coating softening caused by high humidity environments.

[0031] In an environmentally friendly coating for long-term tobacco beetle inhibition, modified Fe-MOG, Cr-ZnGa2O4 nanospheres, and natural plant extracts such as menthol, eugenol, matrine, and tea polyphenols achieve long-term inhibition through a synergistic effect. This effectively addresses issues such as morphological instability and volatilization of active ingredients in harsh storage environments such as high temperature and humidity. Fe-MOG is a metal-organic gel with excellent three-dimensional porosity and high flexibility. Modified Fe-MOG is obtained by chemically grafting phosphate groups onto its surface. The modified Fe-MOG exhibits excellent hydrothermal stability and maintains a stable crystal structure even in high-temperature and high-humidity environments. During the preparation of the environmentally friendly coating solution, the modified Fe-MOG's unique three-dimensional porous network structure, combined with the surface-grafted phosphate groups, significantly enhances the interfacial bonding with the Cr-ZnGa2O4 nanospheres by forming Fe-O-Zn / Fe-O-Cr covalent bridges. This allows the Cr-ZnGa2O4 nanospheres and active ingredients, such as natural plant extracts, to be effectively loaded into a composite controlled-release structure, achieving efficient storage and sustained release. Under high temperature and humidity conditions, the modified Fe-MOG's pore structure contracts. The excellent hydrophobicity and controllability of the phosphate groups on its surface enable the modified Fe-MOG to maintain a "closeable" microporous structure under these conditions. Combined with the dense structure of the Cr-ZnGa2O4 nanospheres, this creates a hydrophobic interface, forming a dense barrier layer on the surface of the composite controlled-release structure, inhibiting water ingress and suppressing the rapid dissipation and thermal degradation of active ingredients, thereby preventing the rapid inactivation of active ingredients such as natural plant extracts under high temperature and humidity conditions. Cr-ZnGa2O4 nanospheres are typical rare earth-doped luminescent / photothermal perovskite nanomaterials with excellent thermal stability and mechanical strength. They can significantly enhance the coating's ability to retain its morphology under high temperature and high humidity conditions. At the same time, chromium doping significantly enhances the absorption capacity and local photothermal effect of Cr-ZnGa2O4 nanospheres in the visible light region, improves the activity of the nanospheres under low-energy light conditions, and gives them excellent photothermal responsiveness. Cr-ZnGa2O4 nanospheres can undergo photothermal conversion effect under weak visible light irradiation to form a "micro-thermal stress zone". The heat released induces the opening of the microscopic channels of the modified Fe-MOG structure through the Fe-O-Zn / Fe-O-Cr covalent bond bridge, prompting the precise release of the active ingredients loaded therein, realizing "weak light-triggered controlled release". At the same time, the released heat can also interfere with the temperature and humidity conditions for the hatching of tobacco beetle eggs, induce behavioral disorders in adults, and form reactive oxygen species to destroy the tobacco beetle's epidermal wax layer and surface lipid substances, causing its dehydration and death and restricted behavior, thereby achieving the purpose of non-contact repellent and physiological interference insect inhibition. Even if the concentration of the active plant ingredients decreases after volatilization, the coating still has a secondary active insect inhibition function.Therefore, the modified Fe-MOG, Cr-ZnGa2O4 nanospheres and natural plant extracts formed a composite controlled-release structure with moisture-heat adaptive closure and weak light-triggered release without relying on large amounts of chemical pesticides. The three worked together to achieve continuous inhibition of tobacco beetles and ensure that the coating maintained long-term effectiveness and morphological stability in complex storage environments such as high temperature and high humidity.

[0032] (3) Beneficial effects

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Modified Fe-MOG, Cr-ZnGa2O4 nanospheres, and natural plant extracts form a composite controlled-release structure with adaptive moisture and heat containment and weak light-triggered release, synergistically achieving long-term inhibition of tobacco beetles and ensuring the coating maintains long-term effectiveness and morphological stability in complex storage environments such as high temperature and humidity.

[0035] 2. The modified Fe-MOG exhibits excellent hydrothermal stability. Its unique three-dimensional porous network structure, combined with the Fe-O-Zn / Fe-O-Cr covalent bridging, can effectively load active ingredients such as Cr-ZnGa2O4 nanospheres and natural plant extracts to form a composite controlled-release structure, achieving both efficient storage and sustained release.

[0036] 3. Under high temperature and high humidity conditions, the modified Fe-MOG pore structure shrinks. Combined with the excellent hydrophobicity of the surface phosphate groups and the dense structure of the Cr-ZnGa2O4 nanospheres, a hydrophobic interface is formed, creating a dense barrier layer on the surface of the composite controlled-release structure, inhibiting water ingress and simultaneously suppressing the rapid dissipation and thermal degradation of the active ingredient.

[0037] 4. Cr-ZnGa2O4 nanospheres can form a "micro-thermal stress zone" through the photothermal conversion effect. The released heat induces the opening of microscopic pores in the modified Fe-MOG structure through the Fe-O-Zn / Fe-O-Cr covalent bond bridges, promoting the precise release of the loaded active ingredients, achieving "weak light-triggered controlled release";

[0038] 5. Cr-ZnGa2O4 nanospheres can also achieve a non-chemical auxiliary insect inhibition effect. Even if the concentration of active plant ingredients decreases after volatilization, the coating still has a secondary active insect inhibition function. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the SEM image of the modified Fe-MOG in Example 1 of the present invention;

[0040] Figure 2 This is the SEM image of Cr-ZnGa2O4 nanospheres in Example 1 of the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] The experimental equipment and preparations for the embodiments described below are as follows: electronic balance (Sartorius, Germany), electric constant temperature water bath (Jiangsu Kedao), magnetic stirrer (Shanghai Meiyingpu), ultrasonic analyzer (Shanghai Yixin), high-speed centrifuge (Guangzhou Jidi), vacuum filter (Huzhou Henglv), vacuum drying oven (Shanghai Jiecheng), muffle furnace (Hangzhou Lantian Instrument), hydrothermal reactor (Anhui Kemi), scanning electron microscope (Zeiss, Germany), specific surface area analyzer (Beijing Best Instrument Technology); chemicals and reagents were purchased from Sigma-Aldrich.

[0043] Example 1: This example discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, comprising the following raw materials in parts by weight: 6 parts of Cr-ZnGa2O4 nanospheres, 10 parts of hydroxypropyl methylcellulose, 14 parts of polylactic acid, 9 parts of bentonite, 5 parts of menthol, 4 parts of eugenol, 4 parts of matrine, and 3 parts of tea polyphenols. The environmentally friendly coating for long-term inhibition of tobacco beetles also includes modified Fe-MOG, wherein the modified Fe-MOG and Cr-ZnGa2O4 nanospheres are in a weight ratio of 12:6. The modified Fe-MOG is prepared by grafting phosphate groups on the surface of the Fe-MOG. The particle size of the modified Fe-MOG is 95 nm and the specific surface area is 392 m 2 / g.

[0044] In the environmentally friendly coating for long-term inhibition of tobacco beetles, modified Fe-MOG, Cr-ZnGa2O4 nanospheres and natural plant extracts such as menthol, eugenol, matrine and tea polyphenols achieve long-term inhibition of tobacco beetles through synergistic effects, and effectively solve the problems of unstable morphology of the coating and easy volatilization of active ingredients in harsh storage environments such as high temperature and high humidity. 3+ The metal organic gel constructed by coordination bonds with 1,3,5-benzenetricarboxylic acid ligands has a typical three-dimensional porous network structure and high flexibility. The modified Fe-MOG is obtained by grafting phosphate groups on its surface through chemical modification. Figure 1The SEM image of the modified Fe-MOG shows that the modified Fe-MOG has a highly developed pore structure and a high specific surface area. In addition, the modified Fe-MOG has excellent hydrothermal stability and can maintain a stable crystal structure under high temperature and high humidity conditions. During the preparation of the environmentally friendly coating solution, the unique three-dimensional porous network structure of the modified Fe-MOG can effectively adsorb natural plant extracts such as menthol, eugenol, matrine and tea polyphenols. The phosphate groups (-PO4) provided by the phosphate groups grafted on its surface interact with the Zn on the surface of the Cr-ZnGa2O4 nanospheres. 2+ and Cr 3+ The formation of a stable Fe-O-Zn / Fe-O-Cr covalent bond bridge significantly enhances the interfacial binding force to the Cr-ZnGa2O4 nanospheres, and can effectively load the active ingredients such as Cr-ZnGa2O4 nanospheres and natural plant extracts to form a composite controlled release structure, achieving efficient storage and sustained release. The highly flexible three-dimensional network structure of the modified Fe-MOG gives it adjustable microporous channels and dynamic responsiveness. Under high temperature and high humidity conditions, the organic ligand chain segments in the modified Fe-MOG undergo thermally induced conformational changes, causing its pore structure to shrink. At the same time, the phosphate groups on its surface have good hydrophobicity and regulatory capabilities, and are compatible with Fe 3+ The strong coordination effect of the modified Fe-MOG enables it to maintain the "closable" state of the microporous structure under high temperature and high humidity conditions, and combines with the dense structure of the Cr-ZnGa2O4 nanospheres to form a hydrophobic interface. Figure 2This SEM image of Cr-ZnGa2O4 nanospheres shows their compact structure and spherical morphology. The modified Fe-MOG and Cr-ZnGa2O4 nanospheres work together to form a dense, continuous nanocomposite barrier layer on the surface of the composite controlled-release structure, further enhancing the overall waterproof and impermeability properties of the coating, inhibiting water ingress and the rapid dissipation and thermal degradation of active ingredients, thereby preventing the rapid loss of active ingredients such as natural plant extracts under high temperature and high humidity conditions. Cr-ZnGa2O4 nanospheres are typical rare earth-doped photothermal perovskite nanomaterials with excellent thermal stability and mechanical strength, significantly enhancing the coating's ability to retain its morphology under high temperature and high humidity conditions. Chromium doping also significantly enhances the Cr-ZnGa2O4 nanospheres' absorption capacity and localized photothermal effect in the visible light region, namely their light capture and heating efficiency. This improves the Cr-ZnGa2O4 nanospheres' activity under low-energy light conditions, giving them excellent photothermal responsiveness. Cr-ZnGa2O4 nanospheres can undergo photothermal conversion under weak visible light irradiation to form a microscale "micro-thermal stress zone". The local heat released is transmitted to the modified Fe-MOG structure bonded to its interface through the Fe-O-Zn / Fe-O-Cr covalent bond bridge, inducing the opening of the microscopic pores of the modified Fe-MOG porous skeleton structure, prompting the precise release of the active ingredients loaded therein, realizing "weak light-triggered controlled release". At the same time, the released heat can also interfere with the temperature and humidity conditions for the incubation of tobacco beetle eggs, inducing behavioral disorders in adults, and forming reactive oxygen species to destroy the tobacco beetle's cuticular wax layer and surface lipid substances, destroying its protective barrier, causing the insect to lose water and die of dehydration, effectively inhibiting the growth and reproduction of tobacco beetles, achieving the purpose of insect inhibition through non-contact repellency and physiological interference. Even if the concentration of the active plant ingredients decreases after volatilization, the coating still has a secondary active insect inhibition function, realizing long-term and stable pest control. Therefore, the modified Fe-MOG, Cr-ZnGa2O4 nanospheres and natural plant extracts formed a composite controlled-release structure with moisture-heat adaptive closure and weak light-triggered release without relying on large amounts of chemical pesticides. The three worked together to achieve continuous inhibition of tobacco beetles and ensure that the coating maintained long-term effectiveness and morphological stability in complex storage environments such as high temperature and high humidity.

[0045] The preparation method of the modified Fe-MOG comprises:

[0046] S11. Under nitrogen protection and stirring, ferric chloride was dissolved in a N,N-dimethylformamide / anhydrous ethanol mixed solvent, where the volume ratio of N,N-dimethylformamide to anhydrous ethanol was 1:2. After stirring at room temperature for 1.5 hours, 1,3,5-benzenetricarboxylic acid was added, where the weight ratio of ferric chloride to 1,3,5-benzenetricarboxylic acid was controlled to be 1:0.5. Stirring was continued for 3 hours, and the pH was adjusted to 4.0 with triethylamine. The temperature was raised to 75°C, and the reaction was continued with stirring for 7 hours. The mixture was then aged for 14 hours to obtain a first mixed solution.

[0047] S12. The first mixed solution was subjected to high-speed centrifugation at 10,000 rpm for 10 min. The separated gel was washed three times with N,N-dimethylformamide and anhydrous ethanol alternately and then vacuum dried at 60 ° C for 22 h to obtain Fe-MOG and ground into a powder for later use.

[0048] S13. The Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated. The volume ratio of anhydrous ethanol and purified water in the mixed solvent was 9:1, the ultrasonic frequency was 45 kHz, and after ultrasonic treatment for 20 min, dodecyl phosphate was added. The ultrasonic treatment was continued for 45 min and the pH value was adjusted to 5.0 with acetic acid to obtain a second mixed solution.

[0049] S14. The second mixed solution was transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at 95°C for 22 hours. The solution was then centrifuged at 12,000 rpm for 20 minutes. The separated solid was washed alternately with acetone and anhydrous ethanol three times and then vacuum dried at 60°C for 22 hours to obtain the modified Fe-MOG. The powder was then ground into a powder for later use.

[0050] The weight ratio of Fe-MOG to dodecyl phosphate is 1:0.5.

[0051] The preparation method of the Cr-ZnGa2O4 nanospheres comprises:

[0052] S21. Prepare a mixed solvent of purified water and ethylene glycol in a volume ratio of 1:1 under stirring, dissolve zinc nitrate, gallium nitrate and chromium chloride in the mixed solvent, and control the Zn 2+ and Ga 3+ The molar ratio of 1:2 was 1:2, and the mixture was stirred for 4 h to obtain a third mixed solution;

[0053] S22 was added to the third mixed solution under stirring trisodium citrate complex reaction, stirring was continued for 2h and then transferred to a polytetrafluoroethylene reactor for hydrothermal reaction at a reaction temperature of 180 ° C, the reaction was carried out for 14h to obtain a fourth mixed solution;

[0054] S23. The fourth mixed solution was vacuum filtered, and the resulting precipitate was washed three times with purified water and anhydrous ethanol alternately and then vacuum dried at 60 ° C. After drying for 10 h, the Cr-ZnGa2O4 precursor was ground into a powder and set aside;

[0055] S24. The Cr-ZnGa2O4 precursor powder was placed in a muffle furnace and calcined at 850°C with a heating rate of 5°C / min. After calcination for 5 h, Cr-ZnGa2O4 nanospheres were obtained and ground into powder for later use.

[0056] The nanometer size of the Cr-ZnGa2O4 nanospheres is 135 nm and the specific surface area is 55 m 2 / g.

[0057] The Cr doping amount in the Cr-ZnGa2O4 nanospheres is 0.75 mol%.

[0058] A method for preparing an environmentally friendly coating for long-term tobacco beetle inhibition, which is applied to the environmentally friendly coating for long-term tobacco beetle inhibition, comprises the following steps:

[0059] S31. The modified Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated. The volume ratio of anhydrous ethanol to purified water in the mixed solvent was 1:1. The ultrasonic frequency was 45 kHz and the ultrasonic temperature was 60°C. After ultrasonic treatment for 20 min, Cr-ZnGa2O4 nanospheres, menthol, eugenol, matrine, and tea polyphenols were added in sequence and stirred at high speed at 1200 rpm and 80°C for 10 h to obtain a fifth mixed solution.

[0060] S32. Hydroxypropyl methylcellulose, polylactic acid and bentonite were sequentially added to the fifth mixed solution under stirring, the stirring temperature was 60 ° C, and after stirring for 2h, ultrasonic treatment was performed at an ultrasonic frequency of 45 kHz, and the environmental coating solution was obtained after ultrasonic treatment for 5h;

[0061] S33. The environmentally friendly coating solution is evenly applied to the surface of the substrate using a brush coating method. The coated substrate is dried at 60° C. for 4 h to obtain the long-lasting environmentally friendly coating for inhibiting tobacco beetles.

[0062] Example 2: This example discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, comprising the following raw materials in parts by weight: 4 parts of Cr-ZnGa2O4 nanospheres, 8 parts of hydroxypropyl methylcellulose, 12 parts of polylactic acid, 8 parts of bentonite, 4 parts of menthol, 3 parts of eugenol, 3 parts of matrine, and 2 parts of tea polyphenols. The environmentally friendly coating for long-term inhibition of tobacco beetles also includes modified Fe-MOG, wherein the modified Fe-MOG and Cr-ZnGa2O4 nanospheres are in a weight ratio of 12:4. The modified Fe-MOG is prepared by grafting phosphate groups on the surface of the Fe-MOG. The particle size of the modified Fe-MOG is 112 nm and the specific surface area is 380 m 2 The preparation method of the modified Fe-MOG and Cr-ZnGa2O4 nanospheres in this embodiment is the same as that in Example 1. The preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this embodiment is the same as that in Example 1.

[0063] Example 3: This example discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, comprising the following raw materials in parts by weight: 8 parts of Cr-ZnGa2O4 nanospheres, 12 parts of hydroxypropyl methylcellulose, 16 parts of polylactic acid, 10 parts of bentonite, 6 parts of menthol, 5 parts of eugenol, 5 parts of matrine, and 4 parts of tea polyphenols. The environmentally friendly coating for long-term inhibition of tobacco beetles also includes modified Fe-MOG, wherein the modified Fe-MOG and Cr-ZnGa2O4 nanospheres are in a weight ratio of 12:8. The modified Fe-MOG is prepared by grafting phosphate groups on the surface of the Fe-MOG. The particle size of the modified Fe-MOG is 108 nm and the specific surface area is 390 m 2 The preparation method of the modified Fe-MOG and Cr-ZnGa2O4 nanospheres in this embodiment is the same as that in Example 1. The preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this embodiment is the same as that in Example 1.

[0064] Control Group 1: This example differs from Example 1 in that it does not contain modified Fe-MOG. This example discloses an environmentally friendly coating for long-term tobacco beetle suppression, comprising the following raw materials by weight: 6 parts Cr-ZnGa2O4 nanospheres, 10 parts hydroxypropyl methylcellulose, 14 parts polylactic acid, 9 parts bentonite, 5 parts menthol, 4 parts eugenol, 4 parts matrine, and 3 parts tea polyphenols. The preparation method for the Cr-ZnGa2O4 nanospheres in this example is the same as that in Example 1. The preparation method for this example of an environmentally friendly coating for long-term tobacco beetle suppression is the same as that in Example 1.

[0065] Control group 2: The difference between this embodiment and embodiment 1 is that Cr-ZnGa2O4 nanospheres are not contained. This embodiment discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, comprising the following raw materials in parts by weight: 10 parts of hydroxypropyl methylcellulose, 14 parts of polylactic acid, 9 parts of bentonite, 5 parts of menthol, 4 parts of eugenol, 4 parts of matrine, and 3 parts of tea polyphenols. The environmentally friendly coating for long-term inhibition of tobacco beetles also includes modified Fe-MOG, wherein the modified Fe-MOG and Cr-ZnGa2O4 nanospheres are prepared by grafting phosphate groups on the surface of Fe-MOG. The particle size of the modified Fe-MOG is 95 nm and the specific surface area is 392 m 2 / g; the preparation method of the modified Fe-MOG in this embodiment is the same as that in Example 1. The preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this embodiment is the same as that in Example 1.

[0066] Control Group 3: This example differs from Example 1 in that it does not contain modified Fe-MOG and Cr-ZnGa2O4 nanospheres. This example discloses an environmentally friendly coating for long-term tobacco beetle inhibition, comprising the following raw materials by weight: 10 parts hydroxypropyl methylcellulose, 14 parts polylactic acid, 9 parts bentonite, 5 parts menthol, 4 parts eugenol, 4 parts matrine, and 3 parts tea polyphenols. The preparation method for this example is the same as that for Example 1.

[0067] Effect evaluation: Insect inhibition effect test: Seven uncovered rectangular boxes with specifications of 80×60×40cm were made from wood. The environmentally friendly coating solution obtained from each experimental group was evenly applied to the inner surface of the rectangle by brushing and dried at 60℃ for 4h. The blank group was not coated with the coating. The experimental temperature was set at 30℃ and the air humidity was 50%. A 10×10cm tobacco leaf was placed in each box. After 40 third-instar larvae of tobacco beetles were introduced, the top was covered with a breathable film. The number of tobacco beetles was recorded on the 1st, 3rd, 7th, 14th and 20th days respectively.

[0068]

[0069] Table 1 shows the statistical results of the insecticide efficacy test for the environmentally friendly coatings prepared in each experimental group. As can be seen from Table 1, the number of tobacco beetles in the blank group continued to rise, reaching 136 on the 20th day, showing a clear reproductive trend. Significant differences were observed in the insecticide efficacy of the environmentally friendly coatings prepared in each experimental group. Comparing Examples 1-3 with Control Groups 1-3, it was found that the environmentally friendly coatings of Examples 1-3 exhibited significant insecticide efficacy, with all tobacco beetles dying from Days 1 to 14, and no recurrence by Day 20. This indicates that the active ingredients in these environmentally friendly coatings possess sustained, long-lasting, and stable insecticide efficacy. The environmentally friendly coatings of Control Groups 1-3 were less effective than those of Examples 1-3, with some tobacco beetles still surviving on Day 20, indicating an unstable insecticide efficacy. In particular, Control Group 3, where the environmentally friendly coating was prepared without the addition of modified Fe-MOG and Cr-ZnGa2O4 nanospheres, showed a significant rebound in tobacco beetle populations.

[0070] High temperature and high humidity morphological stability experiment: The environmentally friendly coating solution obtained from each experimental group was evenly applied to the surface of the wood substrate by brushing and dried at 60℃ for 4h. The wood substrate was then placed in a constant temperature and humidity chamber with the experimental temperature set at 40℃ and the air humidity set at 90% to simulate a high temperature and high humidity environment. Three parallel experiments were set for each experimental group. The changes in the coating surface condition were observed with the naked eye on the 1st, 7th, 14th and 30th days. The coatings were divided into three levels according to the surface condition, namely stable and intact (A), slightly unstable (B) and obviously unstable (C). Specifically, stable and intact (A): the coating surface has no obvious defects, the gloss remains good, and there is almost no change; slightly unstable (B): the coating surface has very small bubbles or slight cracks, no obvious peeling, the gloss is slightly reduced, and there is a slight blackening in some areas; obviously unstable (C): large-area defects or structural damage appear on the coating surface, the gloss is severely weakened, and the color is uneven.

[0071]

[0072] Table 2 shows the statistical comparison results of the high-temperature and high-humidity morphological stability experiments of the environmentally friendly coatings prepared in each experimental group. During the entire test period, the environmentally friendly coatings of Examples 1 to 3 were always in a stable and intact state, indicating that they have excellent morphological retention in a high-temperature and high-humidity environment. However, the environmentally friendly coatings of Control Groups 1 to 3 began to show varying degrees of instability from the 7th day, and then gradually deteriorated, and their stability was much lower than that of the environmentally friendly coatings of Examples 1 to 3.

[0073] Through the limited experiments above, the application effect of the environmentally friendly coating for long-term inhibition of tobacco beetles in Example 1 of the present invention is significant. By introducing natural plant extracts and combining modern nanotechnology to introduce modified Fe-MOG and Cr-ZnGa2O4 nanospheres, a composite controlled-release structure with moisture-heat adaptive sealing and weak light-triggered release is synergistically constructed. This can not only inhibit the rapid escape and thermal degradation of active ingredients, but also effectively resist stress damage in high temperature and high humidity environments. This enables the coating to continuously and effectively inhibit the growth and reproduction of tobacco beetles without relying on large amounts of chemical pesticides. At the same time, it ensures that the environmentally friendly coating maintains good morphological stability and inhibitory effect under harsh environmental conditions such as high temperature and high humidity, ensuring long-term effectiveness and reliability in practical applications.

[0074] Finally, it should be noted that although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An environmentally friendly coating for long-term inhibition of tobacco beetles, characterized in that: The invention comprises the following raw materials in parts by weight: 4-8 parts of Cr-ZnGa2O4 nanospheres, 8-12 parts of hydroxypropyl methylcellulose, 12-16 parts of polylactic acid, 8-10 parts of bentonite, 4-6 parts of menthol, 3-5 parts of eugenol, 3-5 parts of matrine, and 2-4 parts of tea polyphenols; The environmentally friendly coating for long-term tobacco beetle inhibition further comprises: modified Fe-MOG; The modified Fe-MOG and Cr-ZnGa2O4 nanospheres are in a weight ratio of 12:(4-8); The modified Fe-MOG is prepared by grafting phosphate groups on the surface of Fe-MOG. The particle size of the modified Fe-MOG is 95-115 nm and the specific surface area is 380-400 m 2 / g.

2. The environmentally friendly coating for long-term inhibition of tobacco beetles according to claim 1, characterized in that: The preparation method of the modified Fe-MOG comprises: S11. Under nitrogen protection and stirring, dissolve ferric chloride in a N,N-dimethylformamide / anhydrous ethanol mixed solvent, where the volume ratio of N,N-dimethylformamide to anhydrous ethanol in the mixed solvent is 1:

2. After stirring at room temperature for 1-2 hours, add 1,3,5-benzenetricarboxylic acid, controlling the weight ratio of ferric chloride to 1,3,5-benzenetricarboxylic acid to be 1:0.

5. Stirring is continued for 2-4 hours, and the pH is adjusted to 3.8-4.2 with triethylamine. Simultaneously, the temperature is raised to 70-80°C, and the reaction is continued with stirring for 6-8 hours. The mixture is then allowed to stand and age for 12-14 hours to obtain a first mixed solution. S12. The first mixed solution was subjected to high-speed centrifugation at a speed of 8000-10000 rpm for 5-10 min. The separated gel was washed three times with N,N-dimethylformamide and anhydrous ethanol alternately and then vacuum dried at a drying temperature of 55-65°C for 18-24 h to obtain Fe-MOG, which was ground into a powder and set aside. S13. The Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated in a 9:1 volume ratio of anhydrous ethanol to purified water at a frequency of 40 to 50 kHz. After ultrasonic treatment for 15 to 20 minutes, dodecyl phosphate was added. Ultrasonic treatment was continued for 30 to 45 minutes, and the pH was adjusted to 4.8 to 5.2 with acetic acid to obtain a second mixed solution. S14. The second mixed solution is transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a temperature of 85-105°C for 20-24 hours. The reaction is then followed by high-speed centrifugation at a speed of 10,000-12,000 rpm for 15-20 minutes. The separated solid is washed alternately with acetone and anhydrous ethanol three times and then vacuum dried at a temperature of 55-65°C for 18-24 hours to obtain the modified Fe-MOG, which is then ground into a powder for later use.

3. The environmentally friendly coating for long-term inhibition of tobacco beetles according to claim 2, characterized in that: The weight ratio of the Fe-MOG to the dodecyl phosphate is 1:(0.4-0.6).

4. The environmentally friendly coating for long-term inhibition of tobacco beetles according to claim 1, characterized in that: The preparation method of the Cr-ZnGa2O4 nanospheres comprises: S21. Prepare a mixed solvent of purified water and ethylene glycol in a volume ratio of 1:1 under stirring, dissolve zinc nitrate, gallium nitrate and chromium chloride in the mixed solvent, and control the Zn 2+ and Ga 3+ The molar ratio of 1:2 was 1:2, and the mixture was stirred for 2 to 4 hours to obtain a third mixed solution; S22. Under stirring, trisodium citrate was added to the third mixed solution for complexation reaction, and stirring was continued for 1 to 2 hours, and then transferred to a polytetrafluoroethylene reactor for hydrothermal reaction at a reaction temperature of 160 to 180 ° C. After 12 to 14 hours, a fourth mixed solution was obtained; S23. The fourth mixed solution was vacuum filtered, and the resulting precipitate was washed three times with purified water and anhydrous ethanol alternately, and then vacuum dried at a drying temperature of 55 to 65 ° C. After drying for 8 to 12 hours, the Cr-ZnGa2O4 precursor was obtained and ground into a powder for later use; S24. Calcine the Cr-ZnGa2O4 precursor powder in a muffle furnace at a temperature of 800-900°C at a heating rate of 5°C / min for 4-6 h to obtain Cr-ZnGa2O4 nanospheres, which are then ground into a powder for later use.

5. The environmentally friendly coating for long-term tobacco beetle inhibition according to claim 4, characterized in that: The nanometer size of the Cr-ZnGa2O4 nanospheres is 120-150 nm, and the specific surface area is 35-65 m 2 / g.

6. The environmentally friendly coating for long-term inhibition of tobacco beetles according to claim 4, characterized in that: The Cr doping amount in the Cr-ZnGa2O4 nanospheres is 0.5-1 mol%.

7. A method for preparing an environmentally friendly coating for long-term inhibition of tobacco beetles, which is used to prepare the environmentally friendly coating for long-term inhibition of tobacco beetles as claimed in any one of claims 1 to 6, characterized in that: The method comprises the following steps: S31. The modified Fe-MOG powder was dispersed in an anhydrous ethanol / purified water mixed solvent and ultrasonically treated. The volume ratio of anhydrous ethanol to purified water in the mixed solvent was 1:

1. The ultrasonic frequency was 40-50 kHz and the ultrasonic temperature was 55-65°C. After ultrasonic treatment for 15-20 min, Cr-ZnGa2O4 nanospheres, menthol, eugenol, matrine, and tea polyphenols were added in sequence and stirred at a high speed of 1000-1200 rpm and a stirring temperature of 75-85°C for 8-12 h to obtain a fifth mixed solution. S32. Hydroxypropyl methylcellulose, polylactic acid and bentonite were sequentially added to the fifth mixed solution under stirring, with stirring at a temperature of 55 to 65 ° C. After stirring for 1 to 2 hours, ultrasonic treatment was performed at an ultrasonic frequency of 40 to 50 kHz for 4 to 6 hours to obtain the environmentally friendly coating solution; S33. The environmentally friendly coating solution is evenly applied to the surface of the substrate using a brush coating method. The coated substrate is dried at 50-70°C for 2-4 hours to obtain the long-lasting environmentally friendly coating that inhibits tobacco beetles.

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