Agricultural bactericidal sustained-release granules and preparation method thereof

Abstract

The invention discloses an agricultural bactericidal sustained-release particle and a preparation method thereof, and belongs to the technical field of pesticides, the agricultural bactericidal sustained-release particle is characterized in that a component A is wrapped by a component B to form an internal and external dual sustained-release structure, and modified porous diatomite and porous starch with different pore diameters are mixed to achieve the purpose of gradient sustained release, and are cross-linked with polyvinyl alcohol and a cross-linking agent A to obtain the agricultural bactericidal sustained-release particle. A stable three-dimensional network structure is formed, so that the load is more stable, and the application mechanical property is better. In addition, D-tyrosine is added into the component A, so that the sterilizing effect can be enhanced; the component B adopts a degradable material, aminopropyl oligosiloxane and a cross-linking agent B are introduced into a polylactic acid-polyethylene glycol block copolymer, so that the adhesiveness of the polylactic acid-polyethylene glycol block copolymer on the surface of the component A is enhanced, the cross-linking agent B can also form a chemical bonding effect with the cross-linking agent A, polyvinyl alcohol and modified porous diatomite, and a bonding network delays film layer breakage, so that the adhesion of the film layer on the surface of the component A is enhanced. And moreover, the antibacterial agent is added, so that the synergistic sterilization and antibiosis effects can be realized, and the persistence is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticides, in particular to an agricultural fungicide sustained-release granule and a preparation method thereof. BACKGROUND

[0002] Pesticides are widely used in agriculture to ensure crop yield and quality. However, the original pesticide generally has the disadvantages of poor water solubility and stability, and most of them cannot be directly applied and need to be processed into various dosage forms. However, some toxic organic solvents and adjuvants are often added in traditional dosage forms, which has a large negative impact on the ecological system, low utilization rate of active ingredients and causes irreversible toxicity to non-target species. In addition, plant pathogens pose a great threat to crop growth and are the main cause of crop yield and quality decline. With the increasing risk of pesticide resistance, there is an urgent need for safer and more effective fungicides.

[0003] At the same time, the traditional pesticide application method also has many problems, such as short duration of efficacy, low drug utilization rate, and greater negative impact on the environment. In order to solve these problems, the sustained-release preparation technology has gradually been valued. By wrapping the active ingredients in appropriate carrier materials, slow release of the drug can be achieved, achieving the purpose of prolonging the effective period, reducing the frequency of pesticide application, and improving the utilization rate of the drug. There are also many studies on pesticide sustained-release granules in the prior art, such as Chinese patent application No. CN202410468454.5, which discloses a drug carrier, a drug-loaded particle and a preparation method thereof. The drug carrier comprises Fe3O4 nanoparticles and a CuMn2O4 shell wrapping the Fe3O4 nanoparticles. The drug carrier can achieve synergistic fungicidal effect of photo-thermal and chemical pesticides after loading pesticides, and has a sustained-release effect, which can reduce the frequency of pesticide application, reduce pesticide resistance and improve the control effect. However, the existing technology still has the problems of poor application stability and poor fungicidal effect of the prepared agricultural sustained-release granule. Therefore, it is urgent to develop or improve an agricultural fungicide sustained-release granule and a preparation method thereof for sustainable development of agriculture. SUMMARY

[0004] Therefore, in order to solve one of the above technical problems, the present application provides an agricultural fungicide sustained-release granule and a preparation method thereof, and the specific technical solutions are as follows: An agricultural fungicide sustained-release granule, which comprises component A and component B, and the weight ratio of the component A to the component B is (5-20):(1-9). The component A comprises the following raw materials by weight: 25-40 parts of modified porous diatomite, 15-20 parts of porous starch, 8-13 parts of polyvinyl alcohol, 7-12 parts of disintegrant, 0.01-5 parts of fungicide, 0.5-10 parts of D-tyrosine, 1-3 parts of crosslinking agent A, 0.1-0.8 parts of wetting agent and 50-100 parts of solvent A; The component B comprises the following raw materials by weight: 45-50 parts of polylactic acid-polyethylene glycol block copolymer, 9-12 parts of aminopropyl oligosiloxane, 10-15 parts of sodium carboxymethyl cellulose, 0.01-9 parts of antibacterial agent, 1-3 parts of plasticizer, 5-7 parts of crosslinking agent B and 30-100 parts of solvent B.

[0005] Preferably, the preparation method of the modified porous diatomite is as follows: The porous diatomite is added into 3-aminopropyl triethoxysilane, stirred at a speed of 50-100 r / min at 60-65°C for 20-60 min, then 1-hydroxymethyl pyrazole-3-carboxylic acid is added, and the stirring is continued for 20-30 min to obtain the modified porous diatomite.

[0006] Preferably, the fungicide is at least one of carbendazim, tebuconazole, azoxystrobin and metalaxyl-M.

[0007] Preferably, the disintegrant is at least one of calcium chloride, calcium stearate and magnesium chloride.

[0008] Preferably, the crosslinking agent A is at least one of citric acid and glutaraldehyde.

[0009] Preferably, the wetting agent is at least one of cocamidopropyl betaine and sodium lignosulfonate.

[0010] Preferably, the polylactic acid-polyethylene glycol block copolymer has a molecular weight in the range of 5000-20000 Da, and the ratio of polylactic acid to polyethylene glycol is (5-9) to (1-5).

[0011] Preferably, the antibacterial agent is at least one of chitosan, nano-zinc oxide and nano-magnesium oxide.

[0012] Preferably, the plasticizer is glycerol.

[0013] Preferably, the crosslinking agent B is at least one of polyethylene glycol dimethacrylate, β-cyclodextrin and dextran.

[0014] In addition, the application also provides a preparation method of the agricultural fungicide slow-release granule, which comprises the following steps: Disperse the fungicide in solvent A to obtain a fungicide solution; Mix the modified porous diatomite and porous starch, then add the fungicide solution, stir at a stirring speed of 50 r / min to 100 r / min for 1 h to 3 h, then add polyvinyl alcohol, crosslinking agent A, disintegrating agent and wetting agent, stir at a stirring speed of 100 r / min to 200 r / min at a temperature of 65 DEG C to 75 DEG C for 1 h to 2 h, then add D-tyrosine, stir for 10 min to 30 min, granulate to obtain component A; Add polylactic acid-polyethylene glycol block copolymer to solvent B, stir until uniform, then add aminopropyl oligosiloxane, sodium carboxymethyl cellulose, plasticizer and crosslinking agent B, stir at a temperature of 50 DEG C to 70 DEG C for 1 h to 3 h, then add the antibacterial agent, continue to stir for 20 min to 30 min to obtain component B; Spray the component B on the surface of the component A, then treat at a temperature of 50 DEG C to 70 DEG C for 30 min to 60 min to obtain the agricultural fungicide slow-release granule.

[0015] Compared with the prior art, the present application has the following beneficial effects: 1. The component B is used to wrap the component A to form an internal and external double slow-release structure, and the stability and uniformity of the whole are more excellent after the components and the ratio of the component A are optimized, which has a positive effect on the slow-release effect of the granule, and due to the wrapping of the component B, the rapid loss of the effective component can be reduced after rainwater washing or ultraviolet irradiation, which is also helpful to achieve the slow-release purpose, and the environmental protection is more excellent, so the present application has good application and promotion prospects.

[0016] 2. The modified porous diatomite and porous starch with different pore sizes are mixed as the slow-release matrix to achieve the purpose of gradient slow release, and the system formed under the interaction of polyvinyl alcohol and crosslinking agent A has more loading crosslinking sites and forms a stable three-dimensional network structure, which improves the loading stability of the effective component while ensuring the application mechanical properties of the agricultural fungicide slow-release granule, and the agricultural fungicide slow-release granule is not easy to break and the loss rate is reduced.

[0017] 3. Component B of the present invention adopts degradable materials, introduces aminopropyl oligosiloxane and crosslinking agent B into polylactic acid-polyethylene glycol block copolymer, can form crosslinked structure not only, strengthen its adhesion on the surface of component A, crosslinking agent B can also form chemical bond with crosslinking agent A, polyvinyl alcohol and modified porous diatomaceous earth in component A, adhesion is more excellent, bonding network delays film layer rupture, makes it have more excellent storage property, in soil environment, gradually degrades, further ensures its sustained release performance. In addition, the addition of antibacterial agent in component B plays the role of synergistically enhancing the bactericidal effect, achieves the purpose of broad-spectrum bactericidal and antibacterial, reduces the amount of pesticide used, and prolongs the lasting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of component A obtained in Example 1 of the present invention; Figure 2 This is a schematic structural diagram of the agricultural bactericidal slow-release granules of Example 1 of the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0020] An agricultural bactericidal slow-release granule in one embodiment of the present invention comprises component A and component B, and the weight ratio of component A to component B is (5-20):(1-9); Component A comprises the following raw materials in parts by weight: 25 to 40 parts of modified porous diatomaceous earth, 15 to 20 parts of porous starch, 8 to 13 parts of polyvinyl alcohol, 7 to 12 parts of disintegrant, 0.01 to 5 parts of bactericide, 0.5 to 10 parts of D-tyrosine, 1 to 3 parts of cross-linking agent A, 0.1 to 0.8 parts of wetting agent, and 50 to 100 parts of solvent A. The component B includes the following raw materials in parts by weight: 45 to 50 parts of polylactic acid-polyethylene glycol block copolymer, 9 to 12 parts of aminopropyl oligosiloxane, 10 to 15 parts of sodium carboxymethyl cellulose, 0.01 to 9 parts of antibacterial agent, 1 to 3 parts of plasticizer, 5 to 7 parts of crosslinking agent B, and 30 to 100 parts of solvent B.

[0021] In some embodiments, the preparation method of the modified porous diatomaceous earth is as follows: The porous diatomite is added to 3-aminopropyl triethoxysilane, stirred at a speed of 50r / min~100r / min at 60℃~65℃ for 20min~60min, then 1-hydroxymethyl pyrazole-3-carboxylic acid is added, and stirring is continued for 20min~30min to obtain the modified porous diatomite.

[0022] In some embodiments, the ratio of the porous diatomite, 3-aminopropyl triethoxysilane, and 1-hydroxymethyl pyrazole-3-carboxylic acid is (20~35):(30~55):(1~5) by weight.

[0023] In some embodiments, the average pore size of the modified porous diatomite is 30nm~100nm.

[0024] In some embodiments, the average pore size of the porous starch is 20nm~30nm.

[0025] In some embodiments, the fungicide is at least one of carbendazim, tebuconazole, azoxystrobin, and metalaxyl-M.

[0026] In some embodiments, the disintegrant is at least one of calcium chloride, calcium stearate, and magnesium chloride.

[0027] In some embodiments, the crosslinking agent A is at least one of citric acid and glutaraldehyde.

[0028] In some embodiments, the wetting agent is at least one of cocamidopropyl betaine and sodium lignosulfonate.

[0029] In some embodiments, the solvent A is at least one of methanol, ethyl acetate, chloroform, ethanol, and acetone.

[0030] In some embodiments, the molecular weight of the polylactic acid-polyethylene glycol block copolymer ranges from 5000~20000 Da, and the ratio of polylactic acid to polyethylene glycol is (5~9):(1~5).

[0031] In some embodiments, the antibacterial agent is at least one of chitosan, nano-zinc oxide, and nano-magnesium oxide.

[0032] In some embodiments, the plasticizer is glycerol.

[0033] In some embodiments, the cross-linking agent B is at least one of polyethylene glycol dimethacrylate, beta-cyclodextrin, and dextran.

[0034] In some embodiments, the solvent B is at least one of ethyl acetate and dichloromethane.

[0035] In addition, the present application also provides a preparation method of the agricultural fungicide sustained-release granule, the preparation method comprising the following steps: dispersing the fungicide in the solvent A to obtain a fungicide solution; mixing the modified porous diatomite and porous starch, then adding the fungicide solution, stirring at a stirring speed of 50 r / min to 100 r / min for 1 h to 3 h, then adding polyvinyl alcohol, cross-linking agent A, disintegrating agent, and wetting agent, stirring at a stirring speed of 100 r / min to 200 r / min at a temperature of 65℃ to 75℃ for 1 h to 2 h, then adding D-tyrosine, stirring for 10 min to 30 min, granulating to obtain component A; adding poly(lactic acid)-poly(ethylene glycol) block copolymer to the solvent B, stirring uniformly, then adding aminopropyl oligosiloxane, sodium carboxymethyl cellulose, plasticizer, and cross-linking agent B, stirring at a temperature of 50℃ to 70℃ for 1 h to 3 h, then adding the antibacterial agent, continuing to stir for 20 min to 30 min to obtain component B; spraying the component B on the surface of the component A, then treating at a temperature of 50℃ to 70℃ for 30 min to 60 min to obtain the agricultural fungicide sustained-release granule.

[0036] In some embodiments, the average particle size of the agricultural fungicide sustained-release granule is 2 mm to 5 mm.

[0037] The agricultural fungicide sustained-release granule prepared by the above scheme has an inner-outer double sustained-release structure, high structural stability and uniformity, can achieve significant fungicide sustained-release property, and has good degradability and environmental protection.

[0038] The embodiments of the present application will be described in detail below with reference to specific examples, and the raw materials and reagents used in the examples, which are not described in detail, are commercially available.

[0039] Example 1: A preparation method of an agricultural fungicide sustained-release granule, the preparation method comprising the following steps: adding 30 parts of porous diatomite to 48 parts of 3-aminopropyl triethoxysilane at a rotation speed of 50 r / min, stirring at a temperature of 65℃ for 50 min, then adding 3 parts of 1-hydroxymethyl pyrazole-3-carboxylic acid, continuing to stir for 30 min to obtain modified porous diatomite with an average pore size of 62 nm; By weight, 1 part of metalaxyl-M is dispersed in 50 parts of ethanol to obtain a fungicide solution; then 27 parts of modified porous diatomite and 19 parts of porous starch (pore size of 25 nm) are mixed, and then the fungicide solution is added, stirred at a stirring speed of 50 r / min for 2 h, then 9 parts of polyvinyl alcohol, 3 parts of citric acid, 9 parts of calcium chloride and 0.5 parts of cocamide propyl betaine are added, stirred at a stirring speed of 100 r / min for 1 h at 65°C, and then 2 parts of D-tyrosine is added and stirred for 20 min, granulated to obtain component A; By weight, 46 parts of polylactic acid-polyethylene glycol block copolymer is added to 67 parts of ethyl acetate, stirred uniformly, then 9 parts of aminopropyl oligosiloxane, 11 parts of sodium carboxymethyl cellulose, 3 parts of glycerol and 5 parts of polyethylene glycol dimethacrylate are added, stirred at 55°C for 2 h, and then 5 parts of chitosan is added and stirred for 25 min to obtain component B; By weight, 7 parts of the component B is sprayed on the surface of 15 parts of the component A, and then treated at 65°C for 30 min to obtain an agricultural fungicide slow-release particle with an average particle size of 5 mm.

[0040] Example 2: A preparation method of an agricultural fungicide slow-release particle, the preparation method comprising the following steps: By weight, 31 parts of porous diatomite is added to 49 parts of 3-aminopropyl triethoxysilane, stirred at a stirring speed of 50 r / min at 65°C for 45 min, and then 4 parts of 1-hydroxymethyl pyrazole-3-carboxylic acid is added and stirred for 25 min to obtain modified porous diatomite with an average pore size of 63 nm; By weight, 0.09 parts of metalaxyl-M is dispersed in 50 parts of ethanol to obtain a fungicide solution; then 26 parts of modified porous diatomite and 20 parts of porous starch (pore size of 25 nm) are mixed, and then the fungicide solution is added, stirred at a stirring speed of 50 r / min for 2 h, then 8 parts of polyvinyl alcohol, 3 parts of citric acid, 10 parts of calcium chloride and 0.6 parts of cocamide propyl betaine are added, stirred at a stirring speed of 100 r / min for 1 h at 65°C, and then 3 parts of D-tyrosine is added and stirred for 20 min, granulated to obtain component A; By weight, 45 parts of polylactic acid-polyethylene glycol block copolymer is added to 65 parts of ethyl acetate, stirred uniformly, then 10 parts of aminopropyl oligosiloxane, 10 parts of sodium carboxymethyl cellulose, 3 parts of glycerol and 6 parts of polyethylene glycol dimethacrylate are added, stirred at 55°C for 2 h, and then 6 parts of chitosan is added and stirred for 25 min to obtain component B; Spray 7 parts of component B onto the surface of 15 parts of component A, and then treat at 65°C for 30 min to obtain the agricultural bactericidal slow-release granules with an average particle size of 5 mm.

[0041] Example 3 A preparation method of agricultural bactericidal slow-release granules, comprising the following steps: Add 30 parts of porous diatomite to 50 parts of 3-aminopropyl triethoxysilane, stir at a speed of 50 r / min at 65°C for 60 min, then add 3 parts of 1-hydroxymethyl pyrazole-3-carboxylic acid, and continue to stir for 30 min to obtain the modified porous diatomite with an average pore size of 61 nm; Disperse 1 part of metalaxyl-M in 50 parts of ethanol to obtain a bactericide solution; then mix 25 parts of the modified porous diatomite and 18 parts of porous starch (with a pore size of 25 nm), and then add the bactericide solution, stir at a speed of 50 r / min for 2 h, then add 9 parts of polyvinyl alcohol, 3 parts of citric acid, 11 parts of calcium chloride, and 0.8 parts of cocamide propyl betaine, stir at a speed of 100 r / min at 65°C for 1 h, then add 5 parts of D-tyrosine, stir for 20 min, and granulate to obtain component A; Add 45 parts of polylactic acid-polyethylene glycol block copolymer to 65 parts of ethyl acetate, stir uniformly, then add 12 parts of aminopropyl oligosiloxane, 11 parts of sodium carboxymethyl cellulose, 3 parts of glycerol, and 7 parts of polyethylene glycol dimethacrylate, stir at 60°C for 2 h, then add 9 parts of chitosan, and continue to stir for 30 min to obtain component B; Spray 7 parts of component B onto the surface of 15 parts of component A, and then treat at 65°C for 30 min to obtain the agricultural bactericidal slow-release granules with an average particle size of 5 mm.

[0042] Comparative Example 1 Comparative Example 1 differs from Example 3 in that the ordinary porous diatomite (not modified and with an average pore size of 45 nm) is used to replace the modified porous diatomite in Example 3, and the other conditions are the same as in Example 3.

[0043] Comparative Example 2 Comparative Example 2 differs from Example 3 in that no porous starch is added, and the other conditions are the same as in Example 3.

[0044] Comparative Example 3 Comparative Example 3 differs from Example 3 in that no D-tyrosine is added, and the other conditions are the same as in Example 3.

[0045] Comparative Example 4: Comparative Example 4 is the same as Example 3 except that no citric acid (crosslinking agent A) is added in Comparative Example 4.

[0046] Comparative Example 5: Comparative Example 5 is the same as Example 3 except that polylactic acid is used to replace the polylactic acid-polyethylene glycol block copolymer in Comparative Example 5.

[0047] Comparative Example 6: Comparative Example 6 is the same as Example 3 except that no polyethylene glycol dimethacrylate (crosslinking agent B) is added in Comparative Example 6.

[0048] Comparative Example 7: Comparative Example 7 is the same as Example 3 except that no chitosan (antibacterial agent) is added in Comparative Example 7.

[0049] Comparative Example 8: Comparative Example 8 is the same as Example 3 except that only component A is used in Comparative Example 8, i.e., the process of spraying component B on the surface of component A is not performed.

[0050] I. Adhesion tests were performed on the samples prepared in Examples 1-3 and the comparative samples prepared in Comparative Examples 1-8. The test method was as follows: the original mass M1 of the sample and the comparative sample was respectively weighed by a person skilled in the art, and then placed in a friability tester drum with a baffle. The rotation speed and rotation time were set. During the continuous rotation of the drum, the sample or the comparative sample was repeatedly rotated, rolled, impacted, and slid under the driving principle of the baffle. The particles were continuously subjected to friction. If the adhesion of component A and component B is not strong, component B will not form a complete film and will slowly fall off by itself. A 1.00 mm sieve was used for sieving, and the undersize was the material with poor adhesion. The mass of the undersize was precisely weighed as M2. According to W%= M2 / M1✖100%, the particle stability was judged. If necessary, a magnifying glass or other tools can be used to observe the morphology of the agricultural bactericidal slow-release granules. The results are shown in Table 1 below.

[0051] Table 1: Judgment results Group RPM, Time W% Agricultural fungicide slow release granule state Example 1 20 r / min, 30 min 0.48% 99% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Example 2 20 r / min, 30 min 0.45% 99% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Example 3 20 r / min, 30 min 0.47% 99% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 1 20 r / min, 30 min 1.26% 95% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 2 20 r / min, 30 min 1.38% 95% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 3 20 r / min, 30 min 0.48% 99% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 4 20 r / min, 30 min 16.7% 60% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 5 20 r / min, 30 min 8.2% 81% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 6 20 r / min, 30 min 13.6% 56% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 7 20 r / min, 30 min 5.1% 98% or more of the granules were uniform, the surface was intact, no breakage, no shedding. Comparative Example 8 20 r / min, 30 min 24.7% 39% or more of the granules were uniform, 100% no surface film layer.

[0052] From the data analysis of Table 1, it can be seen that the agricultural bactericidal slow-release particles prepared by the present application have excellent application stability as a whole. After the interaction of component B and component A, the integrity of the particles is higher, thereby ensuring the application quality. Compared with Example 3, the porous diatomite used in Comparative Example 1 is different, and the application is poor compared with Example 3. Without modification, the adhesion between component A and component B is reduced. In Comparative Example 2, no porous starch is added. In addition to the loading effect of porous starch, it also has a certain adhesive effect. Without the addition of porous starch, the adhesion between components is decreased. In Comparative Example 3, D-tyrosine is not added, and the physical properties of the agricultural bactericidal slow-release particles are less affected. In Comparative Example 4, no citric acid is added, which leads to a significant decrease in the crosslinking effect in the components. It is shown that the addition of a certain amount of crosslinking agent can increase the stability of the network structure inside the system. In Comparative Example 5, polylactic acid is used to replace polylactic acid-polyethylene glycol block copolymer, and the compatibility and film-forming property of component B are decreased, which finally affects the particle integrity of the product. In Comparative Example 6, no polyethylene glycol dimethacrylate (crosslinking agent B) is added, which also affects the crosslinking and film-forming properties of the components, and the hydrogen bond interaction between component A is weakened, which leads to a decrease in adhesion. In Comparative Example 7, no chitosan (antibacterial agent) is added, which has little effect on the integrity of the particles. In Comparative Example 8, the film-forming protection of component B is lost, and different degrees of fragmentation occur. It is shown that the synergistic effect of the components in the present application helps to obtain agricultural bactericidal slow-release particles with higher stability and integrity.

[0053] II. Slow-release effect Test method: 60:40 acetonitrile and water were mixed to prepare a release medium. The samples obtained in Examples 1-3 and the comparative samples of Comparative Examples 1-8 were placed in 200 mL of the release medium, and 1 mL was sampled every certain period of time. High performance liquid chromatography was used for detection (conventional technical means, which will not be described here). The results are shown in Table 2.

[0054] Table 2: Slow-release effect (%) Group 0.5h 2h 6h 24h 48h 72h 168h Example 1 3.1 8.4 18.4 41.6 62.3 74.6 88.9 Example 2 3.2 8.7 18.7 42.1 62.5 74.8 89.2 Example 3 3.2 8.5 18.6 41.7 62.4 74.5 89.3 Comparative Example 1 2.9 28.9 50.6 75.6 80.6 86.2 90.5 Comparative Example 2 10.8 22.6 41.2 69.7 89.1 91.4 94.7 Comparative Example 3 3.5 8.9 18.7 42.5 59.8 71.6 89.1 Comparative Example 4 15.1 30.1 56.9 83.4 95.3 97.6 99.0 Comparative Example 5 2.5 6.3 30.2 65.7 79.3 86.1 90.4 Comparative Example 6 15.9 28.9 50.9 77.1 90.2 93.5 96.8 Comparative Example 7 3.7 8.9 18.2 42.7 63.4 74.6 90.2 Comparative Example 8 22.8 36.7 67.6 75.9 96.7 97.8 99.2

[0055] From the data analysis of Table 2, it can be seen that the application has more excellent sustained-release effect through the interaction of components. Compared with Example 3, the ordinary diatomite is used in Comparative Example 1, the pore size is smaller than that of Example 3, it is not modified, and the compatibility in the system is also poorer, resulting in that the application performance of the prepared agricultural fungicidal granules is not as good as that of Example 3; the porous starch is not added in Comparative Example 2, the system performance is reduced, and the gradient pore size gradient is not accurate, affecting the sustained-release effect; D-tyrosine is not added in Comparative Example 3, which has no obvious effect on the sustained-release effect; the crosslinking agent is not added in Comparative Example 4 and Comparative Example 6, the crosslinking degree of the system structure is reduced, affecting the release effect; polylactic acid is used to replace the polylactic acid-polyethylene glycol block copolymer in Comparative Example 5, which cannot balance the hydrophilicity and hydrophobicity, and the use of polylactic acid leads to low initial release efficiency, subsequent gradual penetration and rapid release; chitosan is not added in Comparative Example 7, which has little effect on the film-forming property of component B, and thus the sustained-release effect is not as good as that of Example 3; there is no component A in Comparative Example 8, and the release is rapid.

[0056] III. Field test The fungicidal and antibacterial effects of the samples of Examples 1-3 and the comparative samples of Comparative Examples 1-8 are tested and compared through a greenhouse indoor experiment, and the test area of each group is 20 m 2 , each treatment group is repeated for 3 times, the application time is when the cucumber seedlings are transplanted, the dosage is 1 kg / acre, and the control effect of soil-borne diseases is recorded every certain period of time, and the results are shown in Table 3.

[0057] Table 3: Control effect (%) Group 20d 30d 40d 60d Example 1 85.8 96.7 94.2 92.3 Example 2 86.2 98.4 94.7 91.7 Example 3 88.9 99.5 95.5 93.2 Comparative Example 1 85.4 90.9 92.3 86.5 Comparative Example 2 84.9 92.5 93.5 90.2 Comparative Example 3 75.2 85.6 86.7 87.3 Comparative Example 4 80.2 83.7 87.6 88.3 Comparative Example 5 72.4 78.0 80.4 78.4 Comparative Example 6 81.3 84.6 86.7 87.1 Comparative Example 7 85.6 97.3 94.1 91.0 Comparative Example 8 78.3 81.0 82.4 76.4

[0058] From the data analysis of Table 3, it can be seen that the agricultural fungicidal sustained-release granules of the application have excellent soil-borne disease control effect, and can achieve the purpose of control for a long time. In addition, the addition of D-tyrosine and antibacterial agent has a certain synergistic effect, and achieves more excellent effect. In addition, the preparation raw material part of the application is a degradable material, and the agricultural fungicidal granules have a certain degradability, which is more environmentally friendly.

[0059] In order to further illustrate the agricultural fungicidal granules of the application, the Figure 1 and Figure 2 are further analyzed, wherein, Figure 1 is a structural schematic diagram of component A obtained from Example 1 of the application, and from Figure 1 it can be seen that the components in component A are crosslinked with each other to form a relatively stable network structure, and have a porous structure; Figure 2 is a structural schematic diagram of the agricultural fungicidal sustained-release granules of Example 1 of the application, wherein, Figure 2 from the diagram a in the figure, it can be seen that the agricultural fungicidal sustained-release granules of the application have relatively uniform dispersity and integrity,Figure 2 Figure 2 As can be seen from Figure b in the figure, the agricultural fungicide sustained-release granules of the application have a core-shell structure, component A acts as a core, component B acts as a shell, component B can better wrap component A, forming a double sustained-release structure inside and outside, and no rupture or particle collapse phenomenon is observed, further illustrating that the agricultural fungicide sustained-release granules prepared by the application have excellent application performance and can achieve the purpose of long-term control.

[0060] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with a preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the application. Any modification, equivalent change and modification of the above embodiments made according to the technical essence of the application, without departing from the technical solution of the application, are still within the scope of the technical solution of the application.

Claims

1. An agricultural fungicide slow release granule characterized in that, The agricultural bactericidal slow-release granule comprises component A and component B, and the weight ratio of the component A to the component B is (5-20):(1-9). The component A comprises the following raw materials in parts by weight: modified porous diatomite 25-40 parts, porous starch 15-20 parts, polyvinyl alcohol 8-13 parts, disintegrant 7-12 parts, bactericide 0.01-5 parts, D-tyrosine 0.5-10 parts, crosslinking agent A 1-3 parts, wetting agent 0.1-0.8 parts, and solvent A 50-100 parts. The component B comprises the following raw materials in parts by weight: polylactic acid-polyethylene glycol block copolymer 45-50 parts, aminopropyl oligosiloxane 9-12 parts, sodium carboxymethyl cellulose 10-15 parts, antibacterial agent 0.01-9 parts, plasticizer 1-3 parts, crosslinking agent B 5-7 parts, and solvent B 30-100 parts.

2. The fungicidal slow release granule according to claim 1, characterized in that, The preparation method of the modified porous diatomite is as follows: The porous diatomite is added into 3-aminopropyl triethoxysilane, stirred at a speed of 50-100 r / min at 60-65°C for 20-60 min, then 1-hydroxymethyl pyrazole-3-carboxylic acid is added, and stirring is continued for 20-30 min to obtain the modified porous diatomite.

3. The fungicidal slow release granule according to claim 1, wherein The bactericide is at least one of carbendazim, tebuconazole, azoxystrobin, and metalaxyl-M.

4. The fungicidal slow release granule according to claim 1, wherein The disintegrant is at least one of calcium chloride, calcium stearate, and magnesium chloride.

5. The fungicidal slow release granule according to claim 1, wherein The crosslinking agent A is at least one of citric acid and glutaraldehyde.

6. The fungicidal slow release granule according to claim 1, wherein The polylactic acid-polyethylene glycol block copolymer has a molecular weight in the range of 5000-20000 Da, and the ratio of polylactic acid to polyethylene glycol is (5-9):(1-5).

7. The fungicidal slow release granule according to claim 1, wherein The antibacterial agent is at least one of chitosan, nano-zinc oxide, and nano-magnesium oxide.

8. The fungicidal slow release granule according to claim 1, wherein The plasticizer is glycerol.

9. The fungicidal slow release granule according to claim 1, wherein The crosslinking agent B is at least one of polyethylene glycol dimethacrylate, β-cyclodextrin, and dextran.

10. A process for the preparation of an agricultural fungicide slow release granule, characterized in that, The preparation method is used for preparing the agricultural bactericidal slow-release granule according to any one of claims 1-9, and comprises the following steps: The bactericide is dispersed in the solvent A to obtain a bactericide solution; The modified porous diatomite and the porous starch are mixed, then the bactericide solution is added, stirring is performed at a speed of 50-100 r / min for 1-3 h, then polyvinyl alcohol, the crosslinking agent A, the disintegrant, and the wetting agent are added, stirring is performed at a speed of 100-200 r / min at 65-75°C for 1-2 h, D-tyrosine is further added, stirring is performed for 10-30 min, granulation is performed, and component A is obtained; The polylactic acid-polyethylene glycol block copolymer is added into the solvent B, stirring is performed until uniform, then the aminopropyl oligosiloxane, the sodium carboxymethyl cellulose, the plasticizer, and the crosslinking agent B are added, stirring is performed at 50-70°C for 1-3 h, and the antibacterial agent is further added, stirring is continued for 20-30 min, and component B is obtained; Spray the component B on the surface of the component A, and then treat at 50-70°C for 30-60 min to obtain the agricultural bactericidal slow-release granule.

Images