Environment-friendly coating for long-acting inhibition of cigarette beetles and preparation method of environment-friendly coating

Abstract

The invention relates to the technical field of coating materials, in particular to an environment-friendly coating for long-acting inhibition of cigarette beetles and a preparation method thereof, and the environment-friendly coating comprises the following raw materials: modified Fe-MOG, Cr-ZnGa2O4 nanospheres, hydroxypropyl methyl cellulose, polylactic acid, bentonite, menthol, eugenol, sophocarpidine and tea polyphenol. According to the invention, the modified Fe-MOG, the Cr-ZnGa2O4 nanospheres and the natural plant extract form a damp-heat self-adaptive closed and weak light triggered release composite controlled release structure to synergistically realize long-acting inhibition on the cigarette beetles, so that the morphological stability of the coating in a high-temperature and high-humidity environment is ensured. In a high-temperature and high-humidity environment, channels of the modified Fe-MOG shrink, hydrophobic phosphate groups on the surface and compact structures of the Cr-ZnGa2O4 nanospheres are combined to form a nano barrier layer, rapid dissipation and thermal degradation of active ingredients are inhibited, and the Cr-ZnGa2O4 nanospheres induce the micro channels of the modified Fe-MOG to be opened to release the active ingredients by forming a micro heat stress region. Meanwhile, a non-chemical auxiliary insect inhibition effect is realized.

Description

Technical Field

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

[0002] Tobacco beetles are pests widely distributed in stored foods such as tobacco, spices, and dried fruits. Traditional control methods mainly rely on chemical insecticides. Although effective in the short term, due to their environmental pollution and the development of pest resistance, long-term use will have adverse effects on the environment and ecology. Therefore, for the prevention and control of tobacco beetles, environment-friendly coating materials have gradually become a new solution. By combining natural plant extracts, chemical inhibitors, and functional nanomaterials to form an effective protective layer, it not only reduces the use of insecticides but also avoids environmental pollution. Tobacco is usually stored in a high-humidity and high-temperature environment, which poses a severe challenge to the long-term stability of the coating. If the coating is unstable, resulting in premature release of active ingredients or coating peeling, it will seriously affect its inhibitory effect on tobacco beetles. Therefore, an environment-friendly coating for long-term inhibition of tobacco beetles not only requires persistent insecticidal and repellent functions but also must maintain the stability and functionality of the coating under harsh environmental conditions such as high humidity and high temperature, so as to effectively control tobacco beetles and ensure 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 environment-friendly coating for long-term inhibition of tobacco beetles and a preparation method thereof. By introducing natural plant extracts and combining modern nanotechnology, the coating can effectively inhibit the growth and reproduction of tobacco beetles without relying on a large amount of chemical insecticides, and at the same time ensure that the environment-friendly coating maintains good morphological stability and inhibitory effect under harsh environmental conditions such as high temperature and high humidity, guaranteeing long-term effectiveness and reliability in practical applications.

[0005] (2) Technical Solutions

[0006] To achieve the above object, on the one hand, the present invention provides an environment-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 environment-friendly coating for long-term inhibition of tobacco beetles further comprises:

[0008] Modified Fe-MOG;

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

[0010] The modified Fe-MOG is prepared by grafting phosphate ester 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 includes:

[0012] S11. Under nitrogen protection and stirring, dissolve ferric chloride in a mixed solvent of N,N-dimethylformamide / absolute ethanol. The volume ratio of N,N-dimethylformamide to absolute ethanol in the mixed solvent is 1:2. After stirring at room temperature for 1 - 2 h, add 1,3,5-benzenetricarboxylic acid, and control the weight ratio of ferric chloride to 1,3,5-benzenetricarboxylic acid to be 1:0.5. Continue stirring for 2 - 4 h, then adjust the pH value to 3.8 - 4.2 with triethylamine, and at the same time raise the temperature to 70 - 80 °C. Continue stirring and reacting for 6 - 8 h, and then let it stand and age for 12 - 14 h to obtain the first mixed solution;

[0013] S12. Centrifuge the first mixed solution at a high speed, with a rotation speed of 8000 - 10000 rpm, centrifuge for 5 - 10 min. Wash the separated gel alternately with N,N-dimethylformamide and absolute ethanol 3 times, and then perform vacuum drying. The drying temperature is 55 - 65 °C. After drying for 18 - 24 h, obtain Fe-MOG and grind it into powder for standby;

[0014] S13. Disperse the Fe-MOG powder in a mixed solvent of absolute ethanol / purified water for ultrasonic treatment. The volume ratio of absolute ethanol to purified water in the mixed solvent is 9:1. The ultrasonic frequency is 40 - 50 kHz. After ultrasonic treatment for 15 - 20 min, add dodecyl phosphate ester, and continue ultrasonic treatment for 30 - 45 min. Then adjust the pH value to 4.8 - 5.2 with acetic acid to obtain the second mixed solution;

[0015] S14. Transfer the second mixed solution to a polytetrafluoroethylene reaction kettle for hydrothermal reaction. The reaction temperature is 85 - 105 °C. After reacting for 20 - 24 h, perform high-speed centrifugation separation, with a rotation speed of 10000 - 12000 rpm, centrifuge for 15 - 20 min. Wash the separated solid alternately with acetone and absolute ethanol 3 times, and then perform vacuum drying. The drying temperature is 55 - 65 °C. After drying for 18 - 24 h, obtain the modified Fe-MOG and grind it into powder for standby.

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

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

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

[0019] S22. Add trisodium citrate to the third mixed solution under stirring for complexation reaction, continue stirring for 1 - 2 h, then transfer it to a polytetrafluoroethylene reaction kettle for hydrothermal reaction, with a reaction temperature of 160 - 180 °C, react for 12 - 14 h to obtain a fourth mixed solution;

[0020] S23. Perform vacuum filtration on the fourth mixed solution, wash the obtained precipitate alternately with purified water and absolute ethanol 3 times, then perform vacuum drying at a drying temperature of 55 - 65 °C for 8 - 12 h to obtain a Cr-ZnGa2O4 precursor and grind it into a powder for standby;

[0021] S24. Place the Cr-ZnGa2O4 precursor powder in a muffle furnace for high-temperature calcination, with a calcination temperature of 800 - 900 °C, a heating rate of 5 °C / min, calcine for 4 - 6 h to obtain Cr-ZnGa2O4 nanospheres and grind them into a powder for standby.

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

[0023] Further, 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 preparation method of an environmentally friendly coating for long-term inhibition of tobacco beetles, which is applied to the environmentally friendly coating for long-term inhibition of tobacco beetles and includes the following steps:

[0025] S31. Disperse the modified Fe-MOG powder in an anhydrous ethanol / purified water mixed solvent for ultrasonic treatment. The volume ratio of anhydrous ethanol to purified water in the mixed solvent is 1:1, the ultrasonic frequency is 40 - 50 kHz, the ultrasonic temperature is 55 - 65 °C, after ultrasonic treatment for 15 - 20 min, successively add Cr-ZnGa2O4 nanospheres, menthol, eugenol, matrine, and tea polyphenols and perform high-speed stirring at a rotation speed of 1000 - 1200 rpm, with a stirring temperature of 75 - 85 °C, stir for 8 - 12 h to obtain a fifth mixed solution;

[0026] S32. While stirring, hydroxypropyl methylcellulose, polylactic acid and bentonite are successively added to the fifth mixed solution. The stirring temperature is 55-65°C. After stirring for 1-2 h, ultrasonic treatment is carried out. The ultrasonic frequency is 40-50 kHz. After ultrasonic treatment for 4-6 h, the environmentally friendly coating solution is obtained;

[0027] S33. The environmentally friendly coating solution is evenly coated on the surface of the substrate by the brush coating method. After the coated substrate is dried at 50-70°C for 2-4 h, the environmentally friendly coating with long-term inhibition of tobacco beetles is obtained.

[0028] The action mechanisms of the above raw material components are as follows:

[0029] Menthol, eugenol, matrine and tea polyphenols are all natural plant extracts. Menthol and eugenol have strong volatile odors, which can interfere with the foraging and reproductive behaviors of tobacco beetles and play a repellent role. Matrine and tea polyphenols can poison the nervous system of insects, act on the physiological metabolism of tobacco beetles, affect the growth and development of tobacco beetles, and reduce their reproductive ability. By adding the above natural plant extracts, the use of chemical insecticides is reduced, and the pollution problems and pest resistance problems caused by the overuse of chemical insecticides are avoided.

[0030] Hydroxypropyl methylcellulose is a water-soluble polymer, which can form a uniform and dense coating on the surface of the substrate, improve the adhesion of active ingredients on the surface of the substrate, ensure the stable release of active ingredients, and at the same time can adsorb a small amount of moisture in the air, prevent the coating from cracking due to excessive drying, and improve the durability and service life of the coating. Polylactic acid is a biodegradable polymer material, which can provide good mechanical strength, improve the durability of the coating under external force, enhance the structural stability of the coating, and prevent peeling. Bentonite is a layered silicate mineral, which can improve the moisture resistance of the coating and prevent the loss of components or the softening of the coating caused by a high-humidity environment.

[0031] In an 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 a synergistic effect, and effectively solve problems such as unstable morphology and easy volatilization and inactivation of active ingredients in the coating under harsh storage environments such as high temperature and high humidity. Fe-MOG is a metal-organic gel with good three-dimensional porosity and high flexibility. Modified Fe-MOG is obtained by grafting phosphate groups on its surface through chemical modification. Modified Fe-MOG has excellent hydrothermal stability and can still maintain a stable crystal structure under high temperature and high humidity environments. During the preparation of the environmentally friendly coating solution, the unique three-dimensional porous network structure of modified Fe-MOG, combined with the phosphate groups grafted on its surface, forms Fe-O-Zn / Fe-O-Cr covalent bond bridges with Cr-ZnGa2O4 nanospheres, significantly enhancing the interfacial binding force to Cr-ZnGa2O4 nanospheres. Furthermore, it effectively loads active ingredients such as Cr-ZnGa2O4 nanospheres and natural plant extracts to form a composite controlled-release structure, realizing efficient storage and continuous slow-release functions. Under high temperature and high humidity environments, the pore structure of modified Fe-MOG is in a contracted state, and at the same time, the phosphate groups on its surface have good hydrophobicity and regulation ability, enabling modified Fe-MOG to still maintain the "closable" state of the microporous structure under high temperature and high humidity conditions, and combining with the dense structure of Cr-ZnGa2O4 nanospheres to form a hydrophobic interface, thus forming a dense barrier layer on the surface of the composite controlled-release structure, inhibiting the entry of moisture, while also inhibiting the rapid escape and thermal degradation of active ingredients, avoiding the rapid inactivation of active ingredients such as natural plant extracts under high temperature and high humidity environments. Cr-ZnGa2O4 nanospheres are typical rare-earth doped luminescent / photothermal perovskite nanomaterials with excellent thermal stability and mechanical strength, which can significantly enhance the morphology retention ability of the coating under high temperature and high humidity conditions. At the same time, chromium doping significantly enhances the absorption ability of Cr-ZnGa2O4 nanospheres in the visible light region and the local photothermal effect, improving the activity of the nanospheres under low-energy light conditions and endowing them with excellent photothermal responsiveness. Cr-ZnGa2O4 nanospheres can undergo a photothermal conversion effect under weak visible light irradiation to form a "micro-thermal stress zone". The heat released induces the opening of the microscopic pores of the modified Fe-MOG structure through the Fe-O-Zn / Fe-O-Cr covalent bond bridge, promoting the precise release of the active ingredients loaded therein, realizing "weak light-triggered controlled release". At the same time, the heat released 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 damage the cuticular wax layer and surface lipids of tobacco beetles, resulting in their dehydration death and restricted behavior, achieving the purpose of non-contact repellent and physiological interference for insect inhibition. Even after the concentration of active plant ingredients decreases due to volatilization, the coating still has a secondary active insect inhibition function.Therefore, the modified Fe-MOG, Cr-ZnGa2O4 nanospheres, and natural plant extracts form a composite controlled-release structure with humidity and heat self-adaptive encapsulation and weak-light triggered release without relying on a large amount of chemical insecticides. The three work together to achieve continuous inhibition of tobacco beetles and ensure the long-term effectiveness and morphological stability of the coating in complex storage environments such as high temperature and high humidity.

[0032] (3)Beneficial effects

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The modified Fe-MOG, Cr-ZnGa2O4 nanospheres, and natural plant extracts form a composite controlled-release structure with humidity and heat self-adaptive encapsulation and weak-light triggered release, and work together to achieve long-term inhibition of tobacco beetles and ensure the long-term effectiveness and morphological stability of the coating in complex storage environments such as high temperature and high humidity.

[0035] 2. The modified Fe-MOG has excellent hydrothermal stability. Its unique three-dimensional porous network structure combined with the Fe-O-Zn / Fe-O-Cr covalent bond bridge effect can effectively load active ingredients such as Cr-ZnGa2O4 nanospheres and natural plant extracts to form a composite controlled-release structure, realizing efficient storage and continuous slow-release functions.

[0036] 3. In a high temperature and high humidity environment, the pore structure of the modified Fe-MOG is in a contracted state. Combining the good hydrophobicity of the surface phosphate groups and the dense structure of the Cr-ZnGa2O4 nanospheres forms a hydrophobic interface, thus forming a dense barrier layer on the surface of the composite controlled-release structure to inhibit the entry of moisture, while inhibiting the rapid dissipation and thermal degradation of the active ingredients.

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

[0038] 5. The Cr-ZnGa2O4 nanospheres can also achieve a non-chemical auxiliary insecticidal effect. Even when the concentration of the active plant ingredients decreases after volatilization, the coating still has a secondary active insecticidal function. Description of the drawings

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

[0040] Figure 2 SEM image of the Cr-ZnGa2O4 nanospheres in Example 1 of the present invention. Detailed implementation manners

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] The test equipment and preparations in the following embodiments are as follows: electronic balance (Sartorius, Germany), electrothermal constant temperature water bath (Kedao, Jiangsu), magnetic stirrer (Meiyingpu, Shanghai), ultrasonic instrument (Yixin, Shanghai), high-speed centrifuge (Jidi, Guangzhou), vacuum filtration machine (Henglv, Huzhou), vacuum drying oven (Jiecheng, Shanghai), muffle furnace (Lantian Instrument, Hangzhou), hydrothermal reaction kettle (Kemi, Anhui), scanning electron microscope (Zeiss, Germany), specific surface area analyzer (Beijing Beishide Instrument Technology); chemical drugs and reagents are 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 further comprises modified Fe-MOG. The weight ratio of the modified Fe-MOG to the Cr-ZnGa2O4 nanospheres is 12:6. 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 nm, and the specific surface area is 392 m 2 / g.

[0044] In the environmentally friendly coating for long-term inhibition of tobacco beetles, the 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 a synergistic effect, and effectively solve problems such as unstable morphology and easy volatilization and inactivation of active ingredients in the coating under harsh storage environments such as high temperature and high humidity. Fe-MOG is a metal-organic gel constructed by Fe 3+ and 1,3,5-benzenetricarboxylic acid ligands through coordination bonds, having 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 1SEM image of modified Fe-MOG shows that modified Fe-MOG has a highly developed pore structure and a high specific surface area. Moreover, modified Fe-MOG has excellent hydrothermal stability and can maintain a stable crystal structure in high-temperature and high-humidity environments. During the preparation of the environmental protection coating solution, the unique three-dimensional porous network structure of 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 ester groups grafted on its surface and Zn 2+ and Cr 3+ on the surface of Cr-ZnGa2O4 nanospheres form stable Fe-O-Zn / Fe-O-Cr covalent bond bridges, significantly enhancing the interfacial binding force to Cr-ZnGa2O4 nanospheres. Furthermore, it can effectively load active ingredients such as Cr-ZnGa2O4 nanospheres and natural plant extracts to form a composite controlled-release structure, realizing efficient storage and sustained release functions. The highly flexible three-dimensional network structure of modified Fe-MOG endows it with adjustable microporous channels and dynamic responsiveness. In high-temperature and high-humidity environments, the organic ligand segments in modified Fe-MOG undergo thermally induced conformational changes, causing its pore structure to contract. At the same time, the phosphate ester groups on its surface have good hydrophobicity and regulation ability. The strong coordination with Fe 3+ enables modified Fe-MOG to maintain the "closable" state of the microporous structure under high-temperature and high-humidity conditions, and combined with the dense structure of Cr-ZnGa2O4 nanospheres to form a hydrophobic interface, Figure 2SEM image of Cr-ZnGa2O4 nanospheres shows that the Cr-ZnGa2O4 nanospheres have a compact structure and a spherical morphology. The modified Fe-MOG and Cr-ZnGa2O4 nanospheres act together to form a dense and continuous nano-composite barrier layer on the surface of the composite controlled-release structure, further enhancing the overall waterproof and anti-seepage performance of the coating, inhibiting the entry of moisture, and at the same time inhibiting the rapid dissipation and thermal degradation of active ingredients, avoiding the rapid inactivation of active ingredients such as natural plant extracts in high-temperature and high-humidity environments. Cr-ZnGa2O4 nanospheres are typical rare-earth doped photothermal perovskite nanomaterials with excellent thermal stability and mechanical strength, which can significantly enhance the morphology retention ability of the coating under high-temperature and high-humidity conditions. At the same time, chromium doping significantly enhances the absorption ability and local photothermal effect of Cr-ZnGa2O4 nanospheres in the visible light region, that is, the light capture ability and heat generation efficiency, improving the activity of Cr-ZnGa2O4 nanospheres under low-energy light conditions and endowing them with excellent photothermal responsiveness. Cr-ZnGa2O4 nanospheres can undergo a photothermal conversion effect under weak visible light irradiation to form a microscale "micro-thermal stress zone", and the local heat released is conducted through the Fe-O-Zn / Fe-O-Cr covalent bond bridge to the modified Fe-MOG structure combined with its interface, inducing the opening of the microscopic pores of the modified Fe-MOG porous framework structure, promoting 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 adult behavior disorders, and can also form reactive oxygen species to damage the cuticular wax layer and body surface lipid substances of tobacco beetles, destroying their protective barrier, causing the insect body to lose moisture and dehydrate to death, effectively inhibiting the growth and reproduction of tobacco beetles, achieving the purpose of non-contact repellent and physiological interference to inhibit insects. Even when the concentration of active plant ingredients decreases after volatilization, the coating still has a secondary active insect inhibitory function, realizing long-term and stable pest control. Therefore, the modified Fe-MOG, Cr-ZnGa2O4 nanospheres and natural plant extracts form a composite controlled-release structure of humidity and heat self-adaptive closure and weak light-triggered release without relying on a large amount of chemical pesticides. The three work together to achieve continuous inhibition of tobacco beetles and ensure the long-term effectiveness and morphological stability of the coating in complex storage environments such as high-temperature and high-humidity.

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

[0046] S11. Dissolve ferric chloride in a mixed solvent of N,N-dimethylformamide / absolute ethanol under nitrogen protection and stirring. The volume ratio of N,N-dimethylformamide to absolute ethanol in the mixed solvent is 1:2. After stirring at room temperature for 1.5 h, add 1,3,5-benzenetricarboxylic acid, and control the weight ratio of ferric chloride to 1,3,5-benzenetricarboxylic acid to be 1:0.5. Continue stirring for 3 h, then adjust the pH value to 4.0 with triethylamine, and at the same time raise the temperature to 75 °C. Continue stirring and reacting for 7 h, and then let it stand and age for 14 h to obtain the first mixed solution;

[0047] S12. Perform high-speed centrifugal separation on the first mixed solution at a speed of 10,000 rpm for 10 min. Wash the separated gel alternately with N,N-dimethylformamide and absolute ethanol 3 times, and then perform vacuum drying at a drying temperature of 60 °C. After drying for 22 h, obtain Fe-MOG and grind it into a powder for standby;

[0048] S13. Disperse the Fe-MOG powder in a mixed solvent of absolute ethanol / purified water for ultrasonic treatment. The volume ratio of absolute ethanol to purified water in the mixed solvent is 9:1, the ultrasonic frequency is 45 kHz. After ultrasonic treatment for 20 min, add dodecyl phosphate, and continue ultrasonic treatment for 45 min, then adjust the pH value to 5.0 with acetic acid to obtain the second mixed solution;

[0049] S14. Transfer the second mixed solution to a polytetrafluoroethylene reaction kettle for hydrothermal reaction at a reaction temperature of 95 °C for 22 h, then perform high-speed centrifugal separation at a speed of 12,000 rpm for 20 min. Wash the separated solid alternately with acetone and absolute ethanol 3 times, and then perform vacuum drying at a drying temperature of 60 °C. After drying for 22 h, obtain modified Fe-MOG and grind it into a powder for standby.

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

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

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

[0053] S22. Add trisodium citrate to the third mixed solution under stirring for complexation reaction. Continue stirring for 2 h, then transfer it to a polytetrafluoroethylene reaction kettle for hydrothermal reaction at a reaction temperature of 180 °C for 14 h to obtain the fourth mixed solution;

[0054] S23. Vacuum filter the fourth mixed solution. The obtained precipitate is washed alternately with purified water and absolute ethanol three times and then dried under vacuum. The drying temperature is 60 °C. After drying for 10 h, a Cr-ZnGa2O4 precursor is obtained and ground into a powder for standby.

[0055] S24. Place the Cr-ZnGa2O4 precursor powder in a muffle furnace for high-temperature calcination. The calcination temperature is 850 °C, the heating rate is 5 °C / min, and after calcination for 5 h, Cr-ZnGa2O4 nanospheres are obtained and ground into a powder for standby.

[0056] The nanosize 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 preparation method of an environment-friendly coating for long-term inhibition of tobacco beetles, which is applied to the environment-friendly coating for long-term inhibition of tobacco beetles, includes the following steps:

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

[0060] S32. Under the stirring state, hydroxypropyl methylcellulose, polylactic acid, and bentonite are added to the fifth mixed solution in sequence. The stirring temperature is 60 °C. After stirring for 2 h, ultrasonic treatment is carried out. The ultrasonic frequency is 45 kHz. After ultrasonic treatment for 5 h, the environment-friendly coating solution is obtained.

[0061] S33. Use the brush coating method to evenly coat the environment-friendly coating solution on the surface of the substrate. After the coated substrate is dried at 60 °C for 4 h, the environment-friendly coating for long-term inhibition of tobacco beetles is obtained.

[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 further comprises modified Fe-MOG. The weight ratio of the modified Fe-MOG to the Cr-ZnGa2O4 nanospheres is 12:4. The modified Fe-MOG is prepared by grafting phosphate ester groups on the surface of Fe-MOG. The particle size of the modified Fe-MOG is 112 nm, and the specific surface area is 380 m 2 / g. The preparation methods of the modified Fe-MOG and the Cr-ZnGa2O4 nanospheres in this example are the same as those in Example 1. The preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this example 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 further comprises modified Fe-MOG. The weight ratio of the modified Fe-MOG to the Cr-ZnGa2O4 nanospheres is 12:8. The modified Fe-MOG is prepared by grafting phosphate ester groups on the surface of Fe-MOG. The particle size of the modified Fe-MOG is 108 nm, and the specific surface area is 390 m 2 / g. The preparation methods of the modified Fe-MOG and the Cr-ZnGa2O4 nanospheres in this example are the same as those in Example 1. The preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this example is the same as that in Example 1.

[0064] Control Group 1: The difference between this example and Example 1 is that it does not contain modified Fe-MOG. 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 preparation method of the Cr-ZnGa2O4 nanospheres in this example 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 example is the same as that in Example 1.

[0065] Control Group 2: The difference between this example and Example 1 is that it does not contain Cr-ZnGa2O4 nanospheres. This example discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, which comprises 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 further comprises modified Fe-MOG. The weight ratio of the modified Fe-MOG to the Cr-ZnGa2O4 nanospheres is 12:6. 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 nm, and the specific surface area is 392 m 2 / g; The preparation method of the modified Fe-MOG in this example 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 example is the same as that in Example 1.

[0066] Control Group 3: The difference between this example and Example 1 is that it does not contain modified Fe-MOG and Cr-ZnGa2O4 nanospheres. This example discloses an environmentally friendly coating for long-term inhibition of tobacco beetles, which comprises 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 preparation method of the environmentally friendly coating for long-term inhibition of tobacco beetles in this example is the same as that in Example 1.

[0067] Effect evaluation: Insect inhibition effect test: Select wood to make 7 uncovered rectangular boxes with specifications of 80×60×40 cm. Use the brush coating method to evenly coat the inner surface of the rectangular box with the environmentally friendly coating solution obtained from each experimental group and dry it at 60°C for 4 h. The blank group is not coated with the coating. Set the experimental temperature to 30°C and the air humidity to 50%. Place 10×10 cm tobacco leaves in each box. After introducing 40 third-instar tobacco beetle larvae, cover the top with a breathable membrane, and record the number of tobacco beetles on the 1st, 3rd, 7th, 14th, and 20th days respectively.

[0068]

[0069] Table 1 shows the statistical results of the insect inhibition effect test of the environmentally friendly coatings prepared by each experimental group. It can be seen from Table 1 that the number of tobacco beetles in the blank group continued to increase and reached 136 on the 20th day, showing an obvious reproductive trend. There were obvious differences in the insect inhibition effects of the environmentally friendly coatings prepared by each experimental group. By comparing Examples 1-3 with Controls 1-3, it was found that the environmentally friendly coatings of Examples 1-3 showed significant insect inhibition effects. All the tobacco beetles died from the 1st day to the 14th day and did not relapse on the 20th day, indicating that the active components in the environmentally friendly coatings had the ability to continuously release and maintain long-term and stable insecticidal effects. The insect inhibition effects of the environmentally friendly coatings of Controls 1-3 were not as good as those of Examples 1-3. There were still some tobacco beetles alive on the 20th day, and the insect inhibition effects were unstable. Especially in Control 3, when preparing the environmentally friendly coating, modified Fe-MOG and Cr-ZnGa2O4 nanospheres were not added, and the number of tobacco beetles showed an obvious rebound.

[0070] High-temperature and high-humidity morphological stability experiment: The environmentally friendly coating solutions obtained by each experimental group were evenly coated on the surface of the wood substrate by brushing and dried at 60 °C for 4 h. Then, they were placed in a thermostatic and humidified chamber with the experimental temperature set at 40 °C and the air humidity at 90% to simulate a high-temperature and high-humidity environment. Three parallel experiments were set for each experimental group. The surface conditions of the coatings were observed with the naked eye on the 1st day, 7th day, 14th day, and 30th day. According to the surface conditions of the coatings, they were divided into three levels, namely, stable and intact (A), slightly unstable (B), and significantly unstable (C). Specifically, stable and intact (A): There were no obvious defects on the coating surface, the gloss was maintained well, and there was almost no change; slightly unstable (B): There were extremely small blisters or slight cracks locally on the coating surface, no obvious peeling, the gloss decreased slightly, and there was local slight dullness; significantly unstable (C): There were large-area defects or structural damages on the coating surface, the gloss was severely weakened, and the color was 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 by each experimental group. Throughout the test period, the environmentally friendly coatings of Examples 1-3 were always in a stable and intact state, indicating that they had excellent morphological retention in a high-temperature and high-humidity environment. However, the environmentally friendly coatings of Controls 1-3 showed varying degrees of instability starting from the 7th day and then gradually deteriorated, and their stability was much lower than that of the environmentally friendly coatings of Examples 1-3.

[0073] After the above limited experiments, the application effect of an environment-friendly coating for long-term inhibition of tobacco beetles in Embodiment 1 of the present invention is remarkable. By introducing natural plant extracts and combining with modern nanotechnology to introduce modified Fe-MOG and Cr-ZnGa2O4 nanospheres, a composite controlled-release structure of humidity and heat self-adaptive sealing and weak light-triggered release is synergistically constructed, which can not only inhibit the rapid dissipation and thermal degradation of active ingredients, but also effectively resist stress damage under high temperature and high humidity environments, enabling the coating to continuously and effectively inhibit the growth and reproduction of tobacco beetles without relying on a large amount of chemical insecticides. At the same time, it ensures that the environment-friendly coating maintains good morphological stability and inhibitory effect under harsh environmental conditions such as high temperature and high humidity, guaranteeing the 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 foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An environment-friendly coating for long-term inhibition of tobacco beetles, characterized in that, It includes the following raw materials in parts by weight: 4 - 8 parts of chromium - doped zinc gallate nanospheres (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 environment - friendly coating for long - term inhibiting tobacco beetles further includes: Modified Fe 3+ - Metal-organic gel of trimesic acid (modified Fe-MOG); The weight - ratio of the modified Fe - MOG to the Cr - ZnGa₂O₄ nanospheres is 12:(4 - 8); The modified Fe-MOG is prepared by grafting phosphate ester 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 Lasioderma serricorne according to claim 1, wherein The preparation method of the modified Fe - MOG includes: S11. Under nitrogen protection and stirring, dissolve ferric chloride in a mixed solvent of N,N - dimethylformamide / absolute ethanol. The volume ratio of N,N - dimethylformamide to absolute ethanol in the mixed solvent is 1:

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

5. Continue stirring for 2 - 4 h, then adjust the pH value to 3.8 - 4.2 with triethylamine, and at the same time raise the temperature to 70 - 80 °C. Continue stirring and reacting for 6 - 8 h, and then let it stand and age for 12 - 14 h to obtain the first mixed solution; S12. Carry out high - speed centrifugal separation on the first mixed solution, with a rotation speed of 8000 - 10000 rpm and centrifugation for 5 - 10 min. The separated gel is washed alternately with N,N - dimethylformamide and absolute ethanol 3 times and then vacuum - dried. The drying temperature is 55 - 65 °C, and after drying for 18 - 24 h, Fe - MOG is obtained and ground into a powder for standby; S13. Disperse the Fe - MOG powder in a mixed solvent of absolute ethanol / purified water for ultrasonic treatment. The volume ratio of absolute ethanol to purified water in the mixed solvent is 9:

1. The ultrasonic frequency is 40 - 50 kHz. After ultrasonic treatment for 15 - 20 min, add dodecyl phosphate, and continue ultrasonic treatment for 30 - 45 min, then adjust the pH value to 4.8 - 5.2 with acetic acid to obtain the second mixed solution; S14. Transfer the second mixed solution to a polytetrafluoroethylene reaction kettle for hydrothermal reaction. The reaction temperature is 85 - 105 °C, and after reacting for 20 - 24 h, carry out high - speed centrifugal separation, with a rotation speed of 10000 - 12000 rpm and centrifugation for 15 - 20 min. The separated solid is washed alternately with acetone and absolute ethanol 3 times and then vacuum - dried. The drying temperature is 55 - 65 °C, and after drying for 18 - 24 h, the modified Fe - MOG is obtained and ground into a powder for standby.

3. An environment-friendly coating for long-term inhibition of Lasioderma serricorne 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. An environment-friendly coating for long-term inhibiting tobacco beetles according to claim 1, characterized in that, The preparation method of the Cr - ZnGa₂O₄ nanospheres includes: S21. Prepare a mixed solvent with a volume ratio of purified water to ethylene glycol of 1:1 under stirring, dissolve zinc nitrate, gallium nitrate and chromium chloride in the mixed solvent, control the molar ratio of Zn 2+ and Ga 3+ to be 1:2, and stir for 2 - 4 h to obtain a third mixed solution; S22. Under stirring, add sodium citrate to the third mixed solution for complexation reaction. After continuing stirring for 1 - 2 h, transfer it to a polytetrafluoroethylene reaction kettle for hydrothermal reaction. The reaction temperature is 160 - 180 °C, and after reacting for 12 - 14 h, the fourth mixed solution is obtained; S23. The fourth mixed solution is subjected to vacuum filtration, and the obtained precipitate is washed alternately with purified water and absolute ethanol three times and then dried under vacuum. The drying temperature is 55 - 65 °C. After drying for 8 - 12 h, a Cr-ZnGa₂O₄ precursor is obtained and ground into a powder for standby. S24. The Cr-ZnGa₂O₄ precursor powder is placed in a muffle furnace for high-temperature calcination. The calcination temperature is 800 - 900 °C, and the heating rate is 5 °C / min. After calcination for 4 - 6 h, Cr-ZnGa₂O₄ nanospheres are obtained and ground into a powder for standby.

5. An environment-friendly coating for long-term inhibition of Lasioderma serricorne according to claim 4, characterized in that, The nanosize of the Cr-ZnGa2O4 nanospheres is 120~150 nm, and the specific surface area is 35~65 m 2 / g.

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

7. A preparation method of an environment-friendly coating for long-term inhibition of tobacco beetles, which is applied to prepare an environment-friendly coating for long-term inhibition of tobacco beetles as described in any one of claims 1 to 6, characterized in that, The method comprises the following steps: S31. The modified Fe-MOG powder is dispersed in an ethanol / purified water mixed solvent for ultrasonic treatment. The volume ratio of ethanol to purified water in the mixed solvent is 1:1, the ultrasonic frequency is 40 - 50 kHz, the ultrasonic temperature is 55 - 65 °C. After ultrasonic treatment for 15 - 20 min, Cr-ZnGa₂O₄ nanospheres, menthol, eugenol, matrine, and tea polyphenols are added successively and stirred at a high speed. The rotation speed is 1000 - 1200 rpm, the stirring temperature is 75 - 85 °C, and after stirring for 8 - 12 h, a fifth mixed solution is obtained. S32. Under the stirring state, hydroxypropyl methylcellulose, polylactic acid, and bentonite are added to the fifth mixed solution successively. The stirring temperature is 55 - 65 °C. After stirring for 1 - 2 h, ultrasonic treatment is carried out. The ultrasonic frequency is 40 - 50 kHz, and after ultrasonic treatment for 4 - 6 h, the environmentally friendly coating solution is obtained. S33. The environmentally friendly coating solution is evenly coated on the surface of the substrate by the brushing method. The coated substrate is dried at 50 - 70 °C for 2 - 4 h to obtain the environmentally friendly coating with long-term inhibition of Lasioderma serricorne.

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