Insecticidal nano-suspending agent containing methyl oleate as well as preparation method and application of insecticidal nano-suspending agent

Abstract

The invention discloses a methyl oleate-containing insecticidal nano-suspending agent as well as a preparation method and application thereof. The insecticidal nano-suspending agent comprises the following raw materials in percentage by mass: 10-20% of an insecticidal active ingredient, 3-12% of a dispersing emulsifier, 7-15% of methyl oleate, 3-6% of an anti-freezing agent and the balance of water. The particle size of methyl oleate liquid drops and the particle size distribution stability of effective particles can be effectively controlled by matching the dispersing emulsifier in a reasonable proportion; according to the present invention, the raw pesticide active component adhesion can be easily enhanced, the permeation penetrating through the plant tissue or the insect body tissue membrane can be accelerated, the rain wash resistance effect is good, and more importantly, the problem of substantial decomposition caused by the exposure environment of the raw pesticide can be improved, and the target insecticidal effect of the raw pesticide active component can be effectively promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and in particular relates to an insecticidal nano suspension containing methyl oleate and a preparation method and application thereof. Background Art

[0002] Pesticide water suspension concentrate is a pesticide formulation that is made by mixing water-insoluble solid pesticide technical with adjuvants, and using a wet grinding process to grind the solid technical into fine particles with a particle size D98 of 2-5μm, forming a suspension system uniformly dispersed in water. This formulation has many advantages, including no dust hazard, water as the dispersion medium, good dispersibility and high suspension rate, and a more significant and lasting efficacy than wettable powders. In addition, water suspension concentrates also have the characteristics of small particles, high surface activity, and safety, which can provide better biological effects and physical stability, and are low in cost.

[0003] In recent years, as people's understanding of pesticide pollution has continued to deepen, the utilization rate of the effective ingredients of water suspension concentrates has been highly valued, and the concept of reducing the amount of pesticides and increasing their efficacy has been proposed. At this stage, the usual method is to add synergist ingredients to improve the application by tank mixing, including but not limited to adding methyl oleate, mineral oil, silicone, APG and other ingredients to improve its permeability and spreadability. While this method has a certain improvement in improving the efficacy of the drug, it also requires that the preparations after tank mixing need to be used up as soon as possible within 5 hours to avoid flocculation and floating oil, which will cause the local concentration of the leaf surface to be too high after spraying the solution, resulting in drug damage. In the actual formulation development process, there is also a technical method to emulsify methyl oleate and add it to the formulation system for easy dilution and use. The suspension prepared by this technical method has poor compatibility of the entire formulation system. The oil droplets and the solid raw drug particles of the suspension are of different sizes. The mutual attraction between the particles causes flocculation and aggregation between the raw drug particles; it is very easy to have Ostwald ripening problems. Ostwald ripening causes the change of the particle size distribution of the solid raw drug particles during storage. The suspension stability problem will also be affected accordingly, resulting in stratification and particle deposition of the suspension system under the action of the gravity field. Among them, the reason for the Ostwald ripening problem is that the particle size of the solid raw drug particles is related to the solubility of the solid raw drug particles and each crystalline state. Therefore, if you want to reduce the Ostwald ripening effect, you must reduce the product particle size and system distribution within a stable range. In addition, the high energy consumption and low efficiency brought by the wet grinding process to further reduce the particle size to the range of D98 below 0.5μm have brought new challenges to the cost requirements and market demand of pesticide manufacturers.

[0004] In the list of the top ten emerging technologies in the field of chemistry released by the International Union of Pure and Applied Chemistry (IUPAC) in 2019, nanopesticides ranked first. Experiments by the Chinese Academy of Agricultural Sciences show that nanopesticides can reduce pesticide use by more than 30% and increase pesticide utilization by more than 30%, and eliminate more than 500,000 tons of "triphenyl" solvents each year. Therefore, it is also necessary to develop excellent nanopesticide technology solutions as soon as possible to enhance the competitiveness of corporate products. Summary of the invention

[0005] The following defects exist in the suspension prepared by emulsifying methyl oleate and adding it to the formulation system during the actual formulation development process: the compatibility of the entire formulation system is poor, the oily droplets and the solid technical particles of the suspension are of different sizes, and the mutual attraction between the particles causes flocculation and aggregation between the technical particles; it is very easy to have Ostwald ripening problems, and Ostwald ripening causes the particle size distribution of the solid technical particles to change more during storage; the suspension stability problem will also be affected accordingly, resulting in stratification and particle deposition of the suspension system under the action of the gravity field. The invention provides an insecticidal nano suspension containing methyl oleate, which effectively controls the particle size of methyl oleate droplets and the particle size distribution stability of effective particles by reasonably matching methyl oleate with a dispersing emulsifier, and also solves the problem of system Ostwald ripening and particle size coarsening and swelling caused by adding methyl oleate, an oil phase component, into a nano suspension formulation in the prior art, and can enhance the adhesion of insecticidal active ingredients and accelerate the penetration through the tissue membrane of plant tissue or insect body, has better anti-rainwater scouring effect, improves the problem of insecticidal active ingredients such as avermectin being greatly decomposed in an exposed environment, and effectively promotes the insecticidal effect of the original active ingredients on the target.

[0006] Specifically, the present invention provides a pesticide insecticide nano suspension, characterized in that it comprises the following raw materials in percentage by mass: 10-20% of an insecticidal active ingredient, 3-12% of a dispersing emulsifier, 7-15% of methyl oleate, 3-6% of an antifreeze agent, and the balance is water; the insecticidal active ingredient contains two active ingredients, A and B, the active ingredient A is avermectin, and the active ingredient B is spirotetramat; the particle size D98 of the insecticidal nano suspension is distributed between 200-400nm.

[0007] The present invention also provides a method for preparing the nanosuspension of the present invention, which comprises the following steps:

[0008] (1) mixing the insecticide active ingredient with a portion of the dispersing emulsifier, the antifreeze agent, and the first portion of water, and homogenizing and dispersing the mixture with a nano high-pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm to form a first material;

[0009] (2) The remaining water is mixed with a dispersing emulsifier and methyl oleate, and the mixture is homogenized and dispersed by a nano high pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm to form a second material.

[0010] (3) The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate.

[0011] In a third aspect, the present invention provides use of the insecticide nanosuspension of the present invention in controlling scale insects on citrus trees.

[0012] The present invention has the following beneficial effects:

[0013] 1. The particle size of the methyl oleate insecticidal nano suspension prepared by the present invention is distributed between 200-400 nm, which is reduced to 1 / 10 of the original particle size compared with the ordinary suspension, which helps the active ingredients of the original medicine to quickly penetrate through the tissue membrane of plant tissues or insect bodies, and promotes the insecticidal effect of the active ingredients of the original medicine on the target;

[0014] 2. The particle size of the methyl oleate enhancer is controlled between 200-400nm by a homogenizer, and then mixed with the original nano suspension to form a good dispersion stability. No additional thickeners, stabilizers, and preservatives are needed. This effectively solves the problems of flocculation and Ostwald ripening defects, reduces surface tension on the target, and increases the hydrophilicity or lipophilicity of the original drug particles, thereby improving the efficacy and utilization rate of the active ingredients of the pesticide, reducing the usage and application costs, and reducing pesticide residues and environmental pollution.

[0015] 3. The water-soluble salt containing N, P and K added at the same time in the present invention has both excellent antifreeze effect and the nutrients required by plants. The use of dispersing emulsifiers in a reasonable ratio can significantly improve the HLB value between the oil phase and the water phase in the water suspension, forming a uniform and stable dispersion system, making the dilution dispersion stability better, and remaining stable after being left to stand for 24 hours after dilution, which is convenient for farmers to use; the method achieves the purpose of reducing the loss of pesticides on the surface of plants and leaves, improving the way and efficiency of the active ingredients of pesticides to exert biological activity on the target, directly penetrating the plant and realizing internal conduction, or directly penetrating the wax layer of the insect body, significantly improving the insecticidal effect, and greatly improving the effective utilization rate of pesticides.

[0016] 4. The preparation method of the present invention can efficiently and quickly homogenize the original drug particles and the oil phase droplets to the required particle size range, thereby improving the preparation efficiency. Without significantly increasing the cost, the preparation of the methyl oleate insecticide nanosuspension is achieved, the efficacy is improved, and the degradation process of the pesticide residues in plants, water bodies and other environments is accelerated, the safety of the insecticide nanosuspension to organisms and the environment is improved, the safety of food is improved, the risk of agricultural product residues and environmental pollution is reduced, and the safety of pesticide preparations to the ecological environment is improved. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described with the following specific embodiments, but the present invention is by no means limited to these examples. The following description is only a preferred embodiment of the present invention, which is only used to explain the present invention, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that any modification, equivalent replacement or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be based on the attached claims.

[0018] Unless otherwise specified, the following components are weight percentages. Unless otherwise expressly indicated, throughout the specification and claims, the term "comprise" or its variations such as "include" or "includes" will be understood to include the stated components or components, without excluding other components or other components. In addition, in order to better illustrate the present invention, numerous specific details are given in the following specific embodiments.

[0019] In the present invention, if there is no special explanation, the percentage refers to the percentage by weight.

[0020] Specifically, the present invention provides a pesticide insecticide nano suspension, which comprises the following raw materials in percentage by mass: 10-20% of an insecticidal active ingredient, 3-12% of a dispersing emulsifier, 7-15% of methyl oleate, 3-6% of an antifreeze agent, and the balance is water; the insecticidal active ingredient contains two active ingredients, A and B, the active ingredient A is avermectin, and the active ingredient B is spirotetramat; the particle size D98 of the insecticidal nano suspension is distributed between 200-400 nm.

[0021] Preferably, in the above nanosuspension, the mass percentage of avermectin is 1-5%; the mass percentage of B-spirotetramat is 9-15%.

[0022] Preferably, in the above-mentioned nanosuspension, the dispersing emulsifier is selected from at least one of the sulfonate dispersing emulsifier JSK5494, the block copolymer dispersing emulsifier AJEC, the polycarboxylate dispersing emulsifier JSN3494, the phosphate dispersing emulsifier FS3000, and the polycarboxylate dispersing emulsifier FS5000; the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.2-0.43, preferably 1:0.33; the weight ratio of the methyl oleate to the dispersing emulsifier is 1:0.14-0.23, preferably 1:0.2.

[0023] Preferably, in the above-mentioned nanosuspension, the antifreeze agent is a water-soluble salt containing N, P, and K, preferably one or more of urea, diammonium phosphate, potassium dihydrogen phosphate, potassium chloride, potassium sulfate, ammonium sulfate, ammonium chloride and ammonium bicarbonate.

[0024] In a second aspect, the present invention provides a method for preparing the nanosuspension of the present invention, comprising the following steps:

[0025] (1) mixing the insecticide active ingredient with a portion of the dispersing emulsifier, the antifreeze agent, and the first portion of water, and homogenizing and dispersing the mixture with a nano high-pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm to form a first material;

[0026] (2) The remaining water is mixed with a dispersing emulsifier and methyl oleate, and the mixture is homogenized and dispersed by a nano high pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm to form a second material.

[0027] (3) The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate.

[0028] Preferably, in the above preparation method, the feed pressure of the nano high pressure homogenizer is 800-1000 bar, and the feed speed is 13-16 kg / min.

[0029] Preferably, in the above preparation method, the insecticidal active ingredient content is 10-20%, the dispersing emulsifier content is 3-12%, the methyl oleate content is 7-15%, the antifreeze content is 3-6%, and the balance is water; the insecticidal active ingredient contains two active ingredients A and B, the active ingredient A is avermectin, and the active ingredient B is spirotetramat

[0030] Preferably, in the above-mentioned preparation method, the mass percentage of avermectin is 1-5%; the mass percentage of B-spirotetramat is 9-15%.

[0031] Preferably, in the above preparation method, the dispersing emulsifier is selected from at least one of the sulfonate dispersing emulsifier JSK5494, the block copolymer dispersing emulsifier AJEC, the polycarboxylate dispersing emulsifier JSN3494, the phosphate dispersing emulsifier FS3000, and the polycarboxylate dispersing emulsifier FS5000; the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.2-0.43, preferably 1:0.33; the weight ratio of the methyl oleate to the dispersing emulsifier is 1:0.14-0.23, preferably 1:0.2.

[0032] Preferably, in the above preparation method, the antifreeze agent is a water-soluble salt containing N, P, and K, preferably one or more of urea, diammonium phosphate, potassium dihydrogen phosphate, potassium chloride, potassium sulfate, ammonium sulfate, ammonium chloride and ammonium bicarbonate.

[0033] The present invention also provides application of the insecticide nano suspension in preventing and controlling scale insects on citrus trees.

[0034] The present invention is further illustrated below through detailed descriptions of specific implementation modes, but this does not limit the present invention and is merely an example.

[0035] Example 1 Preparation of 13% Avermectin and 12% Spirotetramat Nanosuspension

[0036] 3% avermectin, 12% spirotetramat, 5% dispersing emulsifier JSN3494, 4.5% antifreeze urea and 31% water were uniformly mixed, and a nano high pressure homogenizer was set to have a feed pressure of 900 bar and a feed speed of 14 kg / min for homogenization to obtain a first material with a particle size D98 distribution of 300 nm;

[0037] 10% methyl oleate, 2% dispersing emulsifier AJEC and 33% water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 900 bar and a feed speed of 14 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 300 nm;

[0038] The first material and the second material are stirred and mixed to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 300 nm.

[0039] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.33, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.2;

[0040] Example 2 Preparation of 2% Avermectin and 11% Spirotetramat Nanosuspension

[0041] 2% avermectin, 11% spirotetramat, 3.5% dispersing emulsifier JSK5494, 6% antifreeze agent ammonium sulfate and 38% water were uniformly mixed, and a nano high pressure homogenizer was set to have a feed pressure of 800 bar and a feed speed of 13 kg / min for homogenization to obtain a first material with a particle size D98 distribution of 265 nm;

[0042] 8.5% methyl oleate, 1.5% dispersing emulsifier FS3000 and 30% water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 800 bar and a feed speed of 13 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 265 nm;

[0043] The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 265 nm.

[0044] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.27, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.18;

[0045] Example 3 Preparation of 4% Avermectin and 13% Spirotetramat Nanosuspension

[0046] 4% avermectin, 13% spirotetramat, 6.5% dispersing emulsifier JSN3494, 3% antifreeze potassium sulfate and 31% water were uniformly mixed, and a nano high pressure homogenizer was set to have a feed pressure of 1000 bar and a feed speed of 16 kg / min for homogenization to obtain a first material with a particle size D98 distribution of 345 nm;

[0047] 13% methyl oleate, 2.5% dispersing emulsifier FS3000 and 28% water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 1000 bar and a feed speed of 16 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 345 nm;

[0048] The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 345 nm.

[0049] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.38, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.19;

[0050] Example 4 Preparation of 1% Avermectin and 9% Spirotetramat Nanosuspension

[0051] 1% avermectin, 9% spirotetramat, 2% dispersing emulsifier FS5000, 6% antifreeze agent ammonium sulfate and 47% water were mixed evenly, and the nano high pressure homogenizer was set to have a feed pressure of 800 bar and a feed speed of 16 kg / min for homogenization to obtain a first material with a particle size D98 distribution of 200 nm;

[0052] 7% methyl oleate, 1% dispersing emulsifier FS3000 and 27% water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 800 bar and a feed speed of 16 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 200 nm;

[0053] The first material and the second material are stirred and mixed to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 200 nm.

[0054] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.2, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.14;

[0055] Example 5 Preparation of 5% Avermectin and 15% Spirotetramat Nanosuspension

[0056] 5% avermectin, 15% spirotetramat, 8.5% dispersing emulsifier JSN3494, 3% antifreeze agent ammonium chloride and 24% water were uniformly mixed, and a nano high pressure homogenizer was set to have a feed pressure of 1000 bar and a feed speed of 13 kg / min for homogenization to obtain a first material with a particle size D98 distribution of 400 nm;

[0057] 15% methyl oleate, 3.5% dispersing emulsifier FS5000 and 27% water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 1000 bar and a feed speed of 13 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 400 nm;

[0058] The first material and the second material are stirred and mixed to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 400 nm.

[0059] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.43, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.23;

[0060] Comparative Example Preparation of 13% Avermectin and 12% Spirotetramat Nanosuspension

[0061] The preparation method of comparative example 1 is different from the preparation method of example 1 in that:

[0062] In step (1), the amount of dispersing emulsifier JSN3494 is 1.5%; homogenization is performed to obtain a first material with a particle size D98 distribution of 3.6 μm, and the equipment parameters are adjusted so that the particle size cannot continue to decrease;

[0063] In step (2), the amount of dispersing emulsifier AJEC is 1%; homogenization is performed to obtain a second material with a particle size D98 distribution of 850 nm, and the equipment parameters are adjusted so that the particle size cannot be further reduced;

[0064] The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 2.8 μm.

[0065] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.1, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.1;

[0066] Comparative Example 2 Preparation of 3% Avermectin and 12% Spirotetramat Nanosuspension

[0067] The preparation method of comparative example 2 is different from the preparation method of example 1 in that:

[0068] In step (1), the amount of the dispersing emulsifier JSN3494 is 10%; homogenization is performed to obtain a first material with a particle size D98 distribution of 300 μm;

[0069] In step (2), the amount of the dispersing emulsifier AJEC is 3%; homogenization is performed to obtain a second material with a particle size D98 distribution of 300 nm;

[0070] The first material and the second material are stirred and mixed, and the system produces a colloid mass material with poor fluidity. The particle size D98 distribution is measured to be a suspension of 27 μm. The suspension cannot be stored and used normally.

[0071] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.67, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.3;

[0072] Comparative Example 3 Preparation of 3% Avermectin and 12% Spirotetramat Nanosuspension

[0073] The preparation method of comparative example 3 is different from the preparation method of example 1 in that:

[0074] In step (1), the amount of dispersing emulsifier JSN3494 is 2%; homogenization is performed to obtain a first material with a particle size D98 distribution of 3.5 μm, and the equipment parameters are adjusted so that the particle size cannot continue to decrease;

[0075] In step (2), the amount of the dispersing emulsifier AJEC is 5%; a homogenization treatment is performed to obtain a gel-like second material, and its particle size distribution cannot be detected by dilution;

[0076] After the first material and the second material were stirred and mixed, the system was still a colloid mass with poor fluidity. The particle size D98 distribution of the suspension was measured to be 123 μm. The suspension could not be stored and used normally.

[0077] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.13, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.5;

[0078] Comparative Example 4 Preparation of 3% Avermectin and 12% Spirotetramat Nanosuspension

[0079] 3% avermectin, 12% spirotetramat, 5% dispersing emulsifier JSN3494, 4.5% antifreeze urea, 10% methyl oleate, 2% dispersing emulsifier AJEC and 64% water are uniformly mixed, and ground into a suspension with a particle size D98 distribution of 653 μm nanometers by a sand mill filled with zirconium oxide beads with a diameter of 0.1-0.4 mm, and the particle size cannot be controlled below 600 nanometers by extending the sand milling time; finally, an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 653 nm is obtained.

[0080] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.33, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.2.

[0081] Comparative Example 5 Preparation of 3% Avermectin and 12% Spirotetramat Nanosuspension

[0082] 3% avermectin, 12% spirotetramat, 5% dispersing emulsifier JSN3494, 4.5% antifreeze urea, 10% methyl oleate, 2% dispersing emulsifier AJEC and 64% water are mixed evenly, and a nano high-pressure homogenizer is set to have a feed pressure of 900 bar and a feed speed of 14 kg / min for homogenization to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 300 nm.

[0083] In the methyl oleate insecticidal nano suspension prepared by the above method, the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.33, and the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.2;

[0084] Comparative Example 6 Preparation of 2.5% Avermectin and 12.5% ​​Spirotetramat Nanosuspension

[0085] Prepared according to the preparation method of Example 1 in CN 103651443 A:

[0086] Weigh 2.5 kg of avermectin, 12.5 kg of spirotetramidol, 10 kg of dispersant sodium lignin, 0.3 kg of thickener xanthan gum, 2.5 kg of antifreeze agent ethylene glycol, 0.5 kg of defoaming agent silicone oil, and an appropriate amount of pH regulator, adjust the pH to 6.5, add water to 55 kg, mix the above raw materials evenly, set the feed pressure of the nano high pressure homogenizer to 900 bar and the feed speed to 14 kg / min, perform homogenization, and obtain a first material with a particle size D98 distribution of 300 nm;

[0087] 10 kg of methyl oleate, 2 kg of dispersing emulsifier AJEC and 33 kg of water were mixed evenly, and the nano high pressure homogenizer was set to a feed pressure of 900 bar and a feed speed of 14 kg / min for homogenization to obtain a second material with a particle size D98 distribution of 300 nm;

[0088] The first material and the second material are stirred and mixed to obtain an insecticidal nano suspension containing methyl oleate with a particle size D98 distribution of 300 nm.

[0089] Comparison column 7

[0090] Referring to Example 1 in CN 114931143 A, a 28% insecticide suspension containing mineral oil having a particle size D98 distribution of 704 nm was prepared in the following manner;

[0091] A synergistic composition with avermectin and spirotetramat as active ingredients (the mass ratio of avermectin to spirotetramat is 4:24), and mineral oil, D-limonene, and tea saponin. The composition contains, by mass percentage: avermectin: 4%, spirotetramat: 24%, mineral oil: 5%, D-limonene: 1%, tea saponin: 4%, cardanol polyoxyethylene ether phosphate: 3%, polyoxyethylene polyoxypropylene ether block copolymer: 8%, tert-butyl para-diphenol: 0.5%, kason: 0.1%, dimethyl silicone oil: 0.3%, glycerol: 4%, magnesium aluminum silicate 0.3%, xanthan gum 0.25%, and the balance is deionized water. The specific preparation method is as follows:

[0092] 1) Grind avermectin using a planetary ball mill to a particle size of <800 nm and a particle size of

[0093] 0.4mm, intermittent grinding is adopted to prevent the temperature in the grinding chamber from being too high.

[0094] 2) Weigh 4 g of avermectin, 4 g of tea saponin, 3 g of cardanol polyoxyethylene ether phosphate, 0.5 g of tert-butyl paradiphenol, 4 g of glycerol, 0.3 g of dimethyl silicone oil, 0.1 g of kason, 0.3 g of magnesium aluminum silicate, 0.25 g of xanthan gum, 5 g of mineral oil, and the balance of deionized water according to proportion, stir, shear and homogenize, and then wet grind to a particle size D90 <800 nm to obtain an avermectin suspension emulsion.

[0095] 3) Weigh 24 g of spirotetramat and 1 g of D-limonene in proportion, mix, heat to 50° C., stir to completely dissolve the spirotetramat, add 8 g of polyoxyethylene polyoxypropylene ether block copolymer, mix well, and obtain a spirotetramat emulsion.

[0096] 4) Slowly adding the spirotetramat emulsion to the avermectin suspension emulsion at a speed of 300 r / min according to the proportion, and after the two are evenly mixed, a 28% insecticide suspension containing mineral oil with a particle size D98 distribution of 704 nm is obtained.

[0097] Test Example 1:

[0098] The initial particle size and hot storage particle size of Examples 1-5, Comparative Examples 1, 4-6 containing methyl oleate insecticide nano suspensions and Comparative Example 7 containing mineral oil insecticide suspensions were tested respectively, and the results are shown in Table 1. The initial particle size and hot storage particle size were measured by using LS-POP (9) laser particle size analyzer to measure the D98 value; the hot storage particle size was placed in a DHP-9162 electric constant temperature incubator at 54°C for 14 days, then taken out and aired to room temperature to measure the particle size. In addition, the present invention also placed the nano suspensions of Examples 1-5, Comparative Examples 1, 4-6 and the suspension of Comparative Example 7 at room temperature for 14 days and 54°C for 14 days, and the suspension rate of the active ingredient was tested according to Method 1 in GB / T 14825-2006 Method for Determining Suspension Rate of Pesticides. At the same time, the suspension rate data of the preparation placed at room temperature after dilution and standing for 24 hours were tested, and the results are shown in Table 1.

[0099] Table 1 Performance measurement data

[0100]

[0101]

[0102] As shown in Table 1, the methyl oleate insecticidal nano suspension provided by the present invention has a significantly higher stability than the suspension obtained by other methods, and the particle size does not change significantly after hot storage, and the hot storage suspension rate is above 99.9%, and the physical stability is good. In contrast, the suspension obtained by direct sand milling of Comparative Examples 1, 4-6 and Comparative Column 7, or the suspension obtained by changing its dispersing emulsifier, process equipment, and method, all have a significant increase after 14 days of hot storage, or the system is uneven. It can be seen that the dispersing emulsifier of the appropriate proportion disclosed by the present invention, as well as the equipment and preparation method used play a vital role in enhancing the dispersion effect and maintaining the stability of the system. As shown in Table 1, the methyl oleate insecticidal nano suspension provided by the present invention still has a suspension rate higher than 98.9% after dilution for 24 hours, which is more suitable for practical application and does not affect the disadvantage that the liquid prepared on the same day cannot be used the next day.

[0103] Test Example 2:

[0104] The rainwater erosion resistance test was carried out on 10 groups of agents, including Examples 1-5, Comparative Examples 1, 4-6, and Comparative Example 7, respectively, and the mineral oil insecticide suspension containing methyl oleate. The specific test method is as follows: each group of agents is prepared into a suspension with an active ingredient content of 7%, and then diluted 1000 times with tap water for standby use; each treatment group takes 5 citrus leaves of exactly the same size, numbered 1-5, a total of 10 treatment groups, and then takes the same mass of the dilution to spray the leaves numbered 1-5 respectively, and after the liquid is dried for 1 hour, simulates rainfall for spraying (test The simulated rainfall intensity was 100 mm / hour for 30 minutes), and after drying again, the leaves were rinsed with a 90% isopropanol aqueous solution, and the eluted liquid was collected. The content of the active ingredients (avermectin and spirotetramat) in the liquid was determined by high performance liquid chromatography, and the retention of each leaf was calculated to obtain the effective ingredient retention on the leaf. Finally, the percentage of insecticidal active ingredient retention on the leaf was obtained, F = Ni / No, where: F is the retention percentage, Ni is the main component content in the elution liquid of the i-th leaf, and No is the main component content remaining on the leaf after the first drying before the simulated rainfall spraying. The test results are all taken as the average data of the 5 leaves, see Table 2:

[0105]

[0106] It can be seen from the test results in Table 2 that the methyl oleate insecticidal nanosuspension of the embodiment of the present invention has excellent resistance to rain erosion, a smaller particle size, a stable particle size, and the active ingredient particles are easier to penetrate into the target, which improves the decomposition problem of avermectin in the exposed environment. Therefore, the efficacy period is long, the control effect is obvious, and the problem of large-scale loss with the water body after application is avoided. The number of times and the amount of medication are reduced, which saves costs and reduces pollution to the environment.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pesticide nanosuspension, characterized in that: The invention comprises the following raw materials in percentage by mass: 10-20% of insecticidal active ingredients, 3-12% of dispersing emulsifier, 7-15% of methyl oleate, 3-6% of antifreeze agent, and the balance of water; the insecticidal active ingredients contain two active ingredients, A and B, wherein the active ingredient A is avermectin, and the active ingredient B is spirotetramat; and the particle size D98 of the insecticidal nano suspension is distributed between 200-400nm.

2. The nanosuspension according to claim 1, characterized in that: The mass percentage of the avermectin is 1-5%; the mass percentage of the B-spirotetramat is 9-15%.

3. The nanosuspension according to claim 1 or 2, characterized in that: The dispersing emulsifier is selected from at least one of sulfonate dispersing emulsifier JSK5494, block copolymer dispersing emulsifier AJEC, polycarboxylate dispersing emulsifier JSN3494, phosphate dispersing emulsifier FS3000, and polycarboxylate dispersing emulsifier FS5000; the weight ratio of the insecticidal active ingredient to the dispersing emulsifier is 1:0.2-0.43, preferably 1:0.33; the weight ratio of methyl oleate to the dispersing emulsifier is 1:0.14-0.23, preferably 1:0.

2.

4. The nanosuspension according to claim 3, characterized in that: The antifreeze agent is a water-soluble salt containing N, P, and K, preferably one or more of urea, diammonium phosphate, potassium dihydrogen phosphate, potassium chloride, potassium sulfate, ammonium sulfate, ammonium chloride, and ammonium bicarbonate.

5. A method for preparing the nanosuspension according to any one of claims 1 to 4, characterized in that: The steps include: (1) mixing the insecticide active ingredient with a portion of the dispersing emulsifier, the antifreeze agent, and the first portion of water, and homogenizing and dispersing the mixture with a nano high-pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm to form a first material; (2) mixing the remaining water with the dispersing emulsifier and methyl oleate, and homogenizing and dispersing the mixture with a nano high pressure homogenizer to make the particle size D98 distributed between 200 and 400 nm, thereby forming a second material; (3) The first material and the second material are mixed by stirring to obtain an insecticidal nano suspension containing methyl oleate.

6. The preparation method according to claim 5, characterized in that: The feed pressure of the nano high pressure homogenizer is 800-1000 bar, and the feed speed is 13-16 kg / min.

7. Use of the nanosuspension according to any one of claims 1 to 4 in preventing and controlling citrus scale insects.

Images