Preparation method and application of high-efficiency lambda-cyhalothrin nano-microcapsule suspension

Abstract

The application provides a high-efficiency lambda-cyhalothrin nanometer microcapsule suspending agent and a preparation method thereof. A capsule wall material of the pesticide microcapsule suspending agent is a silane modified polyether. The high-efficiency lambda-cyhalothrin nanometer microcapsule suspending agent provided by the application uses the silane modified polyether as the capsule wall material, and has excellent release performance. Not only does the high-efficiency lambda-cyhalothrin nanometer microcapsule suspending agent have good control effect in the early stage of application, but also has a longer effective period.

Description

Technical Field

[0001] This invention belongs to the field of pesticide formulation technology, specifically relating to a method for preparing and applying a highly efficient cyhalothrin nanocapsule suspension. Background Technology

[0002] High-efficiency cyhalothrin is a new generation of type II broad-spectrum, high-efficiency pyrethroid insecticide, with stronger toxicity and faster efficacy. It possesses neurotoxicity, acting on the insect's nervous system by interfering with sodium channels and destroying neurons to achieve its insecticidal effect. It primarily acts through contact and stomach poison, with no systemic action. It is effective against various pests of Lepidoptera, Coleoptera, and Hemiptera, as well as other pests, including spider mites, rust mites, gall mites, and tarsiers. It can control both insects and mites simultaneously. It can control cotton bollworm, cabbage caterpillar, cabbage aphid, tea geometrid moth, tea hairy caterpillar, tea orange gall mite, leaf gall mite, citrus leaf moth, citrus aphid, citrus spider mites, rust mites, peach fruit moth, and pear fruit moth, and can also be used to control various surface and public health pests. For example, to control cotton bollworms, spray with a 2.5% emulsifiable concentrate diluted 1000-2000 times during the peak egg-laying period of the second and third generations; this also controls spider mites, cotton bollworms, and cotton mirid bugs. For cabbage caterpillars and aphids, spray at concentrations of 6-10 mg / L and 6.25-12.5 mg / L, respectively. For citrus leafminers, spray at a concentration of 4.2-6.2 mg / L. The active ingredients in traditional pesticide formulations (such as suspension concentrates and seed coatings) are easily deactivated by external environmental factors such as sunlight and soil pH, resulting in short-lasting effects and reduced pesticide efficacy. Furthermore, existing formulations containing lambda-cyhalothrin, such as emulsifiable concentrates, contain large amounts of organic solvents, polluting the environment. The technical grade of lambda-cyhalothrin is highly irritating to the skin upon contact, and single-agent lambda-cyhalothrin formulations also have certain limitations.

[0003] Silane-modified polyether resin is a technical product that uses silanes containing terminal siloxanes to modify high molecular weight polyether polyols or allyl polyethers. The advantages of this resin are that it releases small-molecule alcohols during curing, which are colorless, odorless, safe, and environmentally friendly. Because it combines the advantages of silicone and polyurethane, it exhibits excellent weather resistance, durability, high resistance to deformation and displacement, good adhesion, coatability, environmental friendliness, low staining, low viscosity, and excellent workability, and has increasingly attracted attention in the domestic construction industry. The main component of silane-modified polyether sealant is silane-modified polyether resin, which is a relatively high-end product on the market. The main raw material suppliers are foreign companies, including Wacker Chemie, Covestro, and Evonik. Its curing reaction principle is as follows: in the presence of moisture and a catalyst in the air, alkoxy groups (-OR) are replaced by hydroxyl groups to generate silanol groups (-Si-OH). The silanol groups (-Si-OH) then crosslink through a condensation reaction to form a three-dimensional network structure. Silane-modified polyethers are insoluble in water, but they solidify rapidly when exposed to water, which greatly limits their application in pesticide microcapsule formulations.

[0004] Microencapsulation technology for pesticides involves encapsulating liquid or solid pesticides within a shell material to create microcapsule formulations with particle sizes typically ranging from 0.1 to 10 μm. This protects the active ingredients from decomposition caused by external factors such as light and air. Microencapsulation is particularly beneficial for environmentally sensitive pesticides, significantly improving their utilization rate. Furthermore, microencapsulation offers advantages such as prolonged drug release time, reduced application frequency, decreased solvent hazard, enhanced efficacy, and improved stability. It has become a crucial development direction for pesticide formulations. The advantage of microencapsulation lies in the use of film-forming materials to encapsulate the core material and isolate it from the external environment during microcapsule preparation, greatly reducing the impact of environmental factors on its properties. This prevents the unstable core material from deteriorating, and under appropriate conditions, the wall material breaks down, releasing the core material to exert its effect. Moreover, the release rate can be controlled by altering the chemical composition and thickness of the wall material. Based on this, in order to achieve the refinement and precision of pesticide formulations, nanocapsules have significant advantages in improving pesticide leaf area deposition and distribution, and enhancing biological activity due to their small size effect and large specific surface area. Summary of the Invention

[0005] The purpose of this invention is to provide a highly efficient cyhalothrin nanocapsule suspension, its preparation method, and its application. This nanocapsule suspension exhibits excellent formulation stability, sustained-release performance, and prevention and control effects.

[0006] The present invention discloses a high-efficiency cyhalothrin nanocapsule suspension, characterized in that the capsule wall material of the pesticide microcapsule suspension is silane-modified polyether.

[0007] Furthermore, the composition of the high-efficiency cyhalothrin nanocapsules, by mass fraction, includes: 10-30 parts of high-efficiency cyhalothrin, 10-20 parts of solvent, 1-8 parts of silane-modified polyether, 1-7 parts of emulsifier, 1-5 parts of silane-modified polyether condensation inhibitor, 0.1-2 parts of acidic pH adjuster, 0.1-0.5 parts of defoamer, 0.1-2 parts of catalyst, 0.1-2 parts of alkaline pH adjuster, 0.1-3 parts of dispersant, 0.1-2 parts of thickener, 0.1-1 part of preservative, 1-5 parts of antifreeze, and deionized water to make up the difference.

[0008] Furthermore, the weight ratio of the active ingredient, high-efficiency cyhalothrin, to the capsule wall material, silane-modified polyether, is 1:0.1-0.8.

[0009] This invention also provides a method for preparing a highly efficient cyhalothrin nanocapsule suspension, the method comprising the following steps:

[0010] (1) Dissolve the active ingredient, high-efficiency cyhalothrin, in a solvent and add silane-modified polyether as the first mixture;

[0011] (2) Mix water, silane-modified polyether inhibitor, emulsifier and defoamer, add acidic pH adjuster to adjust pH value to 3-5, and form a second mixture;

[0012] (3) The first mixture is added dropwise to the second mixture, and high-speed shear emulsification is performed to form a high-efficiency cyhalothrin nanoemulsion;

[0013] (4) Heat the high-efficiency cyhalothrin nanoemulsion prepared in step (3) to 40-70 ℃, add a catalyst and an alkaline pH adjuster to adjust the pH to ≥7, so that the silane-modified polyether is cured, and then keep it at 40-70 ℃ for 2-4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0014] (5) Add dispersant, thickener, preservative and antifreeze to the material obtained in step (4) to obtain the high-efficiency cyhalothrin nanocapsule suspension.

[0015] Beneficial effects

[0016] The beneficial technical effects achieved by this invention are as follows:

[0017] (1) The high-efficiency cyhalothrin nanocapsule suspension provided by the present invention uses silane-modified polyether as the capsule wall material, which has excellent release performance. It not only has a good control effect in the early stage of application, but also has a longer duration of effect.

[0018] (2) Silane-modified polyether materials are prone to solidification when exposed to water, which limits their application in pesticide microcapsule formulations. This invention provides a method for preparing nano-pesticide microcapsule wall materials using silane-modified polyether materials. Before high-speed shear emulsification to form a high-efficiency cyhalothrin nanoemulsion, a silane-modified polyether polycondensation inhibitor and a pH adjustment of 3-5 are added to the second mixture to suppress the problem of silane-modified polyether solidification when exposed to water.

[0019] (3) The high-efficiency cyhalothrin nanocapsule suspension provided by the present invention has a small particle size, which can improve the leaf area deposition and distribution of pesticides and has obvious advantages in enhancing biological activity.

[0020] (4) The nanocapsule suspension provided by the present invention has a high encapsulation rate, stable particle size, good suspension rate and good flowability after 14 days of storage.

[0021] Other features and advantages of the invention will be set forth in the following description, will be apparent from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, etc. Attached Figure Description

[0022] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0023] Figure 1 The cumulative release rate of the drug prepared in the embodiments and comparative examples of the present invention is given. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is illustrated by the following specific embodiments, but the invention is by no means limited to these examples. The following descriptions are merely preferred embodiments of the invention and are used only to explain the invention, but should not be construed as limiting the scope of the patent. It should be noted that any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

[0025] This invention first provides a highly efficient cyhalothrin nanocapsule suspension, wherein the capsule wall material of the pesticide microcapsule suspension is silane-modified polyether.

[0026] The above-mentioned high-efficiency cyhalothrin nanocapsule suspension comprises, by weight: 10-30 parts of high-efficiency cyhalothrin, 10-20 parts of solvent, 1-8 parts of silane-modified polyether, 1-7 parts of emulsifier, 1-5 parts of silane-modified polyether condensation inhibitor, 0.1-2 parts of acidic pH adjuster, 0.1-0.5 parts of defoamer, 0.1-2 parts of catalyst, 0.1-2 parts of alkaline pH adjuster, 0.1-3 parts of dispersant, 0.1-2 parts of thickener, 0.1-1 part of preservative, 1-5 parts of antifreeze, and deionized water to make up the difference.

[0027] Preferably, in the above-mentioned high-efficiency cyhalothrin nanocapsule suspension, the content of the active ingredient high-efficiency cyhalothrin is 10-30%, more preferably 15-25%, and even more preferably 23%.

[0028] In the above-mentioned high-efficiency cyhalothrin nanocapsule suspension, the solvent is selected from at least one of 100# solvent oil, 150# solvent oil, 200# solvent oil, cyclohexanone, xylene, isoflurane, methyl oleate, soybean oil, and ethyl acetate; the emulsifier is selected from castor oil polyoxyethylene ether, nonylphenol polyoxyethylene ether, block polyethers, sodium lignosulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, styrene-maleic anhydride copolymer, fatty alcohol polyoxyethylene ether, and sorbitol polyoxyethylene polyoxypropylene. The silane-modified polyether polyether is selected from one or more of the following: olefinic ether, sorbitan monostearate polyoxyethylene ether, polyvinyl alcohol, polycarboxylate, and naphthalene sulfonate; the silane-modified polyether polycondensation inhibitor is selected from at least one of ethylene glycol, ethanol, isopropanol, phosphoric acid, and citric acid; the acidic pH adjuster is selected from at least one of formic acid, acetic acid, hydrochloric acid, phosphoric acid, sulfuric acid, lactic acid, citric acid, malic acid, tartaric acid, and salicylic acid; the catalyst is an amine or tin-based catalyst, selected from trialkylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, and m-phenylenediamine. The alkaline pH adjuster is selected from at least one of the following: triethanolamine, diethanolamine, monoethanolamine, stannous octoate, stannous butyrate, dibutyltin diacetate, dibutyltin dioctanoate, chelated stannous octoate, and dibutyltin dilaurate; the alkaline pH adjuster is selected from at least one of the following: sodium hydroxide, potassium hydroxide, sodium bicarbonate, ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, and monoethanolamine; the defoamer is selected from amides, organosilicones, polyethers, and modified polyethers; the dispersant is selected from polycarboxylates and sulfuric acid. The thickener is selected from one or more of the following: salts, sulfonates, lignin sulfonates, and block polyethers; preferably, the thickener is selected from one or more of magnesium aluminum silicate, xanthan gum, polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose, bentonite, and silica; preferably, the preservative is selected from one or more of sodium benzoate, Kathon, BHT, potassium sorbate, methylparaben, sodium diacetate, calcium propionate, and sodium lactate; preferably, the antifreeze is selected from one or more of ethylene glycol, propylene glycol, glycerol, and urea.

[0029] Preferably, the average particle size of the high-efficiency cyhalothrin nanocapsule suspension nanocapsules of the present invention is 100~400nm.

[0030] This invention also provides a method for preparing the high-efficiency cyhalothrin nanocapsule suspension described above, which includes the following steps:

[0031] (1) Dissolve the active ingredient, high-efficiency cyhalothrin, in a solvent and add silane-modified polyether as the first mixture;

[0032] (2) Mix water, silane-modified polyether inhibitor, emulsifier and defoamer, add acidic pH adjuster to adjust pH value to 3-5, and form a second mixture;

[0033] (3) The first mixture is added dropwise to the second mixture, and high-speed shear emulsification is performed to form a high-efficiency cyhalothrin nanoemulsion;

[0034] (4) Heat the high-efficiency cyhalothrin nanoemulsion obtained in step (3) to 40-70 ℃, add catalyst and alkaline pH adjuster to adjust pH≥7, so that the silane modified polyether is cured, and then keep it at 40-70 ℃ for 2-4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0035] (5) Add dispersant, thickener, preservative and antifreeze to the material obtained in step (4) to obtain the high-efficiency cyhalothrin nanocapsule suspension.

[0036] In the above preparation method, the content of the active ingredient, high-efficiency cyhalothrin, is 10-30%, preferably 15-25%, and more preferably 23%.

[0037] In the above preparation method, the solvent is selected from at least one of 100# solvent oil, 150# solvent oil, 200# solvent oil, cyclohexanone, xylene, isoflurone, methyl oleate, soybean oil, and ethyl acetate;

[0038] The emulsifier is selected from one or more of castor oil polyoxyethylene ether, nonylphenol polyoxyethylene ether, block polyethers, sodium lignosulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, styrene-maleic anhydride copolymer, fatty alcohol polyoxyethylene ether, sorbitan polyoxyethylene polyoxypropylene ether, sorbitan monostearate polyoxyethylene ether, polyvinyl alcohol, polycarboxylate, and naphthalene sulfonate; the silane-modified polyether polycondensation inhibitor is selected from at least one of ethylene glycol, ethanol, isopropanol, phosphoric acid, and citric acid; the acidic pH adjuster is selected from formic acid, acetic acid, hydrochloric acid, phosphoric acid, sulfuric acid, lactic acid, citric acid, malic acid, tartaric acid, and salicylic acid. At least one of the following: the catalyst is an amine or tin-based substance, selected from at least one of trialkylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, monoethanolamine, stannous octoate, tin butyrate, dibutyltin diacetate, dibutyltin dioctanoate, chelated tin, and dibutyltin dilaurate; the alkaline pH adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, sodium bicarbonate, ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, and monoethanolamine; the defoamer is selected from at least one of amides, organosilicones, polyethers, and polyether-modified polysiloxanes. The dispersant is selected from one or more of polycarboxylates, sulfates, sulfonates, lignin sulfonates, and block polyethers; preferably, the thickener is selected from one or more of magnesium aluminum silicate, xanthan gum, polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose, bentonite, and silica; preferably, the preservative is selected from one or more of sodium benzoate, Kathon, BHT, potassium sorbate, methylparaben, sodium diacetate, calcium propionate, and sodium lactate; preferably, the antifreeze is selected from one or more of ethylene glycol, propylene glycol, glycerol, and urea.

[0039] Preferably, in the above preparation method, before the high-speed shear emulsification forms the high-efficiency cyhalothrin nanoemulsion, a silane-modified polyether condensation inhibitor is added to the second mixture and the pH is adjusted to 3-5 to inhibit the curing of the silane-modified polyether upon contact with water.

[0040] Preferably, in the above preparation method, after high-speed shear emulsification to form a high-efficiency cyhalothrin nanoemulsion, the silane-modified polyether is cured by at least one of the following methods: increasing the temperature, adding a catalyst, or adjusting the pH of the system to ≥7.

[0041] The present invention also provides the application of the above-mentioned high-efficiency cyhalothrin nanocapsule suspension or the high-efficiency cyhalothrin nanocapsule suspension prepared by the preparation method of the present invention, wherein the application refers to the application on crops to kill or control pests.

[0042] Formulation Examples

[0043] Example 1: Preparation of 10% High-Efficiency Cyhalothrin Nanocapsule Suspension

[0044] (1) Mix 10.3g of high-efficiency cyhalothrin technical, 25g of 150# solvent oil and 3g of silane-modified polyether evenly to obtain the oil phase;

[0045] (2) Mix 44.5g water, 5g ethylene glycol, 2g polyvinyl alcohol, 2g block polyether and 0.3g defoamer, add 0.5g citric acid to adjust the pH value to 3-5, and form an aqueous phase;

[0046] (3) The oil phase is added dropwise to the aqueous phase and emulsified by high-speed shearing to form a high-efficiency cyhalothrin nanoemulsion;

[0047] (4) Heat the high-efficiency cyhalothrin nanoemulsion to 40-70 ℃, add 1g of triethanolamine, and then keep it at 65 ℃ for 4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0048] (5) Mix 4 g glycerol, 2 g polycarboxylate, 0.2 g xanthan gum and 0.2 g Kathon evenly, and add to a three-necked flask to obtain 10% high-efficiency cyhalothrin nanocapsule suspension.

[0049] Example 2: Preparation of 15% High-Efficiency Cyfluthrin Nanocapsule Suspension

[0050] (1) Mix 15.4g of high-efficiency cyhalothrin technical, 25g of 150# solvent oil and 3g of silane-modified polyether evenly to obtain the oil phase;

[0051] (2) Mix 39.4g water, 5g ethylene glycol, 2g polyvinyl alcohol, 2g block polyether and 0.3g defoamer, add 0.5g citric acid to adjust the pH value to 3-5, and form an aqueous phase;

[0052] (3) The oil phase is added dropwise to the aqueous phase and emulsified by high-speed shearing to form a high-efficiency cyhalothrin nanoemulsion;

[0053] (4) Heat the high-efficiency cyhalothrin nanoemulsion to 40-70 ℃, add 1g of triethanolamine, and then keep it at 65 ℃ for 4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0054] (5) Mix 4 g glycerol, 2 g polycarboxylate, 0.2 g xanthan gum and 0.2 g Kathon evenly, and add to a three-necked flask to obtain 15% high-efficiency cyhalothrin nanocapsule suspension.

[0055] Example 3: Preparation of 23% High-Efficiency Cyfluthrin Nanocapsule Suspension

[0056] (1) Mix 23.5g of high-efficiency cyhalothrin technical, 25g of 150# solvent oil and 4g of silane-modified polyether evenly to obtain the oil phase;

[0057] (2) Mix 30.3g water, 5g ethylene glycol, 2g polyvinyl alcohol, 2g block polyether and 0.3g defoamer, add 0.5g citric acid to adjust the pH value to 3-5, and form an aqueous phase;

[0058] (3) The oil phase is added dropwise to the aqueous phase and emulsified by high-speed shearing to form a high-efficiency cyhalothrin nanoemulsion;

[0059] (4) Heat the high-efficiency cyhalothrin nanoemulsion to 40-70 ℃, add 1g of triethanolamine, and then keep it at 65 ℃ for 4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0060] (5) Mix 4 g glycerol, 2 g polycarboxylate, 0.2 g xanthan gum and 0.2 g Kathon evenly, and add to a three-necked flask to obtain 23% high-efficiency cyhalothrin nanocapsule suspension.

[0061] Example 4: Preparation of 25% High-Efficiency Cyfluthrin Nanocapsule Suspension

[0062] (1) Mix 25.6g of high-efficiency cyhalothrin technical, 25g of 150# solvent oil and 4g of silane-modified polyether evenly to obtain the oil phase;

[0063] (2) Mix 28.2g water, 5g ethylene glycol, 2g polyvinyl alcohol, 2g block polyether and 0.3g defoamer, add 0.5g citric acid to adjust the pH value to 3-5, and form an aqueous phase;

[0064] (3) The oil phase is added dropwise to the aqueous phase and emulsified by high-speed shearing to form a high-efficiency cyhalothrin nanoemulsion;

[0065] (4) Heat the high-efficiency cyhalothrin nanoemulsion to 40-70 ℃, add 1g of triethanolamine, and then keep it at 65 ℃ for 4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0066] (5) Mix 4 g glycerol, 2 g polycarboxylate, 0.2 g xanthan gum and 0.2 g Kathon evenly, and add to a three-necked flask to obtain 25% high-efficiency cyhalothrin nanocapsule suspension.

[0067] Example 5: Preparation of 30% High-Efficiency Cyhalothrin Nanocapsule Suspension

[0068] (1) Mix 30.7g of high-efficiency cyhalothrin technical, 25g of 150# solvent oil and 5g of silane-modified polyether evenly to obtain the oil phase;

[0069] (2) Mix 22.1g water, 5g ethylene glycol, 2g polyvinyl alcohol, 2g block polyether and 0.3g defoamer, add 0.5g citric acid to adjust the pH value to 3-5, and form an aqueous phase;

[0070] (3) The oil phase is added dropwise to the aqueous phase and emulsified by high-speed shearing to form a high-efficiency cyhalothrin nanoemulsion;

[0071] (4) Heat the high-efficiency cyhalothrin nanoemulsion to 40-70 ℃, add 1g of triethanolamine, and then keep it at 65 ℃ for 4 h. After the heat preservation is completed, cool it down to 20-30 ℃.

[0072] (5) Mix 4 g glycerol, 2 g polycarboxylate, 0.2 g xanthan gum and 0.2 g Kathon evenly, and add to a three-necked flask to obtain 30% high-efficiency cyhalothrin nanocapsule suspension.

[0073] Comparative Example 1:

[0074] This comparative example illustrates the preparation of a 23% high-efficiency cyhalothrin nanocapsule suspension with polyurea as the capsule wall material.

[0075] (1) Weigh 23.5g of high-efficiency cyhalothrin technical material and dissolve it in 25g of 150# solvent oil. Weigh 4g of MDI, add it, and stir evenly to obtain the oil phase.

[0076] (2) Weigh 2 g of block polyether, 2 g of polyvinyl alcohol and 0.3 g of defoamer and dissolve them in 31.3 g of water to obtain an aqueous phase;

[0077] (3) The oil phase was slowly added to the aqueous phase while shearing at 6500 rpm for 10 min to obtain a stable O / W dispersion, which was then transferred to a three-necked flask.

[0078] (4) Weigh 5 g of water and 0.5 g of triethylenetetramine, stir well, and add the solution to a three-necked flask at a speed of 400 rpm;

[0079] (5) Place the three-necked flask in a 60 ℃ water bath and stir and heat for 4 h to carry out interfacial polymerization, and then cool the microcapsule dispersion system to room temperature.

[0080] (6) Weigh 4g glycerol, 2g polycarboxylate, 0.2g xanthan gum and 0.2g Kathon, mix them evenly and add them to a three-necked flask. Stir for 30min to obtain 23% high-efficiency cyhalothrin nanocapsule suspension.

[0081] Comparative Example 2:

[0082] This comparative example illustrates the preparation of a 23% high-efficiency cyhalothrin nanocapsule suspension using urea-formaldehyde resin as the capsule wall material.

[0083] (1) Add 8 g of urea and 16 g of formaldehyde to a three-necked flask equipped with a stirrer, then add 20 g of water, and adjust the pH value to about 8-9 with sodium hydroxide solution. Heat to 70-80 ℃ and react for 1 h to obtain urea-formaldehyde resin prepolymer, then cool to 35 ℃ for later use;

[0084] (2) Dissolve 23.5g of high-efficiency cyhalothrin technical in 25g of 150# solvent oil, and add 2g of polyvinyl alcohol and 2g of block polyether and stir evenly to obtain the oil phase;

[0085] (3) The prepared oil phase is added to the urea-formaldehyde resin prepolymer at a rate of 600 rpm to form a stable O / W system;

[0086] (4) Add acetic acid with a concentration of 4% (mass percentage) in batches within 60 min to adjust the pH value to 2.5 and induce polycondensation reaction; gradually raise the temperature to 40-60 ℃ to solidify the capsule wall; (5) After solidification for 3 h, lower the temperature to room temperature and add triethanolamine to adjust the pH value to 7.0;

[0087] (6) Add 2 g of polycarboxylate, 0.2 g of Kathon, 0.2 g of xanthan gum and 4 g of glycerol, and make up to 100 g with water to obtain 23% high-efficiency cyhalothrin nanocapsule suspension.

[0088] Comparative Example 3:

[0089] In the second mixture, no inhibitors or pH adjusters were added, and the rest of the operation was the same as in Example 3. During shearing, the entire system became paste-like due to the curing of the silane-modified polyether, and the nanoemulsion could not be formed.

[0090] Comparative Example 4:

[0091] In the second mixture, an inhibitor was added and the pH was adjusted to >5. The remaining operations were the same as in Example 3. During shearing, the entire system became paste-like due to the curing of the silane-modified polyether, and the nanoemulsion could not be formed.

[0092] Comparative Example 5: An inhibitor was added to the second mixture, the pH was adjusted to <3, and the rest of the operation was the same as in Example 3. The acidity was too strong during shearing, the viscosity of the whole system increased, and it became paste-like during the heating process.

[0093] Comparative Example 6: In the second mixture, only the pH was adjusted to 3-5, no inhibitor was added, and the rest of the operation was the same as in Example 3. During shearing, the entire system became paste-like due to the curing of the silane-modified polyether, and the nanoemulsion could not be formed.

[0094] Comparative Example 7: In the second mixture, only the inhibitor was added, and the pH was not adjusted to 3-5. The rest of the operation was the same as in Example 3. During shearing, the entire system became paste-like due to the curing of the silane-modified polyether, and the nanoemulsion could not be formed.

[0095] Comparative Example 8: After high-speed shear emulsification to form a high-efficiency cyhalothrin nanoemulsion, the temperature was increased, no catalyst was added or the pH of the system was adjusted to alkaline, and the remaining operations were the same as in Example 3. Microscopic observation showed that the microcapsules exhibited aggregation and low suspension rate.

[0096] II. Performance Testing

[0097] 1) Stability Testing

[0098] The performance of the nanocapsule suspensions prepared in Examples 1-5 and Comparative Examples 1-2 was tested:

[0099] Thermal storage stability test: The high-efficiency cyhalothrin nanocapsule suspension was placed in a container, sealed, and placed in a constant temperature oven at (54±2)℃. After standing for 14 days, it was taken out and its flowability was observed and the suspension rate, encapsulation rate, D50 and D90 values ​​were tested. The sample was measured three times and the average value was taken.

[0100] Cold storage stability test: The high-efficiency cyhalothrin nanocapsule suspension was placed in a container, sealed, and placed in a low-temperature stability tester at (0±2)℃. After standing for 7 days, it was taken out, the flowability was observed, and the suspension rate, encapsulation rate, D50 and D90 values ​​were tested.

[0101] The suspension rate of the microcapsule suspension was determined according to the GB / T 14825-2006 standard.

[0102] Calculate the encapsulation ratio using the following method:

[0103] 1. Preparation of standard solutions:

[0104] Weigh 20 mg (accurate to 0.0002 g) of high-efficiency cyhalothrin standard into a 25 ml volumetric flask, dissolve it in ethyl acetate, dilute to volume with the mobile phase, and shake well before use.

[0105] 2. Determination of free mass fraction

[0106] Weigh approximately 1.0 g (accurate to 0.002 g) of the sample into a 10 ml centrifuge tube. Add approximately 1 g of purified water to dilute the sample, gently shake well, and place in a centrifuge. Centrifuge at 3500 rpm for 30 min. Remove the centrifuge tube and transfer the supernatant to a 25 ml volumetric flask (Note: Do not stir the precipitate). Dilute to volume with ethyl acetate, sonicate to completely dissolve the lambda-cyhalothrin, shake well, cool to room temperature, filter, and set aside.

[0107] 3. Detection of free content using liquid chromatography.

[0108] 4. Encapsulation rate = (Total content - Free content) * 100%;

[0109] Regarding liquidity, it is categorized as follows:

[0110] Level 1: Excellent liquidity, no stratification or clumping;

[0111] Level 2: Liquidity is generally acceptable, with a small amount of stratification and clumping;

[0112] Grade 3: Increased viscosity, with extensive stratification and agglomeration.

[0113] Determination of particle size D50 and D90: The D50 and D90 values ​​of the high-efficiency cyhalothrin nanocapsules of the above examples and comparative examples were determined at room temperature using a Malvern dynamic light scattering nanoparticle size analyzer. The samples were measured three times and the average value was taken.

[0114] Table 1

[0115]

[0116] As shown in Table 1, the nanocapsule suspension obtained by using silane-modified polyether curing as the capsule wall material in this invention exhibits significantly superior encapsulation efficiency, suspension rate, and flowability under different storage conditions, and also demonstrates good stability.

[0117] Table 2

[0118]

[0119] Table 2 shows that the high-efficiency cyhalothrin nanocapsules using silane-modified polyether as the capsule wall material have a D50 particle size of 100-200 nm and a D90 particle size of 100-400 nm. The particle size is relatively small and the distribution is relatively uniform. Compared to the comparative example, using silane-modified polyether as the capsule wall material can produce capsules with smaller particle sizes. Furthermore, under thermal storage conditions, the particle size is more stable using silane-modified polyether as the capsule wall material compared to the comparative example.

[0120] II) Sustained-release performance test

[0121] The release capacity of high-efficiency cyhalothrin nanocapsules (prepared according to Example 3) was determined using the dialysis bag method. Comparative Examples 1-2, high-efficiency cyhalothrin technical material, and high-efficiency cyhalothrin suspension (commercially available high-efficiency cyhalothrin suspension) were used as comparisons. A 1000 Da dialysis bag was boiled in pure water for 30 min, cooled to room temperature, and then rinsed several times with pure water before use. The drug solution was placed into the treated dialysis bag and then into 100 mL of pure water. 1 mL of solution was taken every 10 h, and the content was determined by liquid chromatography. The remaining liquid was replenished with pure water to maintain the total system volume at 100 mL. The cumulative release rate was calculated as follows: Figure 1 As shown.

[0122] according to Figure 1It can be seen that the high-efficiency cyhalothrin technical and suspension concentrate release relatively quickly, with the suspension concentrate releasing completely within 70 hours and the technical concentrate within 80 hours, exhibiting a rapid release rate and a short duration of effect. Comparative Examples 1-2 show relatively slower release compared to the technical concentrate and suspension concentrate, with complete release occurring at 110 hours and 120 hours respectively. The high-efficiency cyhalothrin nanocapsules using silane-modified polyether as the capsule wall material showed a cumulative release rate of 32.58% after 30 hours and 94.42% after 150 hours, demonstrating a longer duration of effect and a high release rate even in the initial testing phase, allowing them to exert their effect early in the spraying process. Therefore, the high-efficiency cyhalothrin nanocapsules prepared in this patent have the advantages of a long duration of effect and a high initial release rate.

[0123] III. Field efficacy trials

[0124] Experiment 1: Field plot experiment for the control of wheat aphids

[0125] The experimental methods were based on GB / T 17980.79-2004, Field Efficacy Test Guidelines for Pesticides (II) Part 79: Insecticides for the Control of Wheat Aphids, determining the field control efficacy of pesticide compositions against wheat aphids. Examples 1-5 of the formulations were used for the field efficacy test against wheat aphids, with water application as a blank control. The experimental location was Zhumadian City, Henan Province. The tested wheat was sown on October 20, 2025, with a plot area of ​​25m². 2 Foliar spraying was used, with the leaves evenly sprayed until the solution was about to drip from the leaves. One application was performed. No other insecticides were used for pest control during the trial. Before application, five sampling points were used, with five wheat plants surveyed at each point, resulting in a fixed sample size of 20 plants per plot. The initial population was recorded. Efficacy was assessed 1 day, 3 days, and 7 days after application, with the number of surviving insects recorded and the control effect calculated.

[0126] Calculate the insect population reduction rate and control effect using the formulas in the guidelines for pesticide field efficacy trials:

[0127] Insect population reduction rate (%) = (Number of live insects before application - Number of live insects after application) * 100 / Number of live insects before application

[0128] Control efficacy (%) = (Pest population reduction rate in the pesticide-treated area - Pest population reduction rate in the blank control area) * 100 / (100 - Pest population reduction rate in the blank control area).

[0129] Table 3

[0130]

[0131] Table 3 shows that the high-efficiency cyhalothrin nanocapsule suspension has a good control effect on wheat aphids. Among them, the 23% high-efficiency cyhalothrin nanocapsule suspension prepared in Example 3 showed the best control effect 1-7 days after application.

[0132] While the embodiments disclosed in this invention are as described above, this invention is not limited thereto. Any person skilled in the art to which this invention pertains may make various simple modifications to the technical solutions of this invention without departing from the spirit and scope disclosed herein, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as part of the content disclosed in this invention and are all within the protection scope of this invention.

Claims

1. A highly efficient cyhalothrin nanocapsule suspension, characterized in that, The capsule wall material of the pesticide microcapsule suspension is silane-modified polyether.

2. The high-efficiency cyhalothrin nanocapsules according to claim 1, characterized in that, By weight, it includes: 10-30 parts of high-efficiency cyhalothrin, 10-20 parts of solvent, 1-8 parts of silane-modified polyether, 1-7 parts of emulsifier, 1-5 parts of silane-modified polyether condensation inhibitor, 0.1-2 parts of acidic pH adjuster, 0.1-0.5 parts of defoamer, 0.1-2 parts of catalyst, 0.1-2 parts of alkaline pH adjuster, 0.1-3 parts of dispersant, 0.1-2 parts of thickener, 0.1-1 parts of preservative, 1-5 parts of antifreeze, and deionized water to make up the difference.

3. The nanocapsule suspension according to claim 1 or 2, characterized in that, The active ingredient, high-efficiency cyhalothrin, has a content of 10-30%, preferably 15-25%, and more preferably 23%; the solvent is selected from at least one of 100# solvent oil, 150# solvent oil, 200# solvent oil, cyclohexanone, xylene, isoflurane, methyl oleate, soybean oil, and ethyl acetate; the emulsifier is selected from castor oil polyoxyethylene ether, nonylphenol polyoxyethylene ether, block polyethers, sodium lignosulfonate, sodium lauryl sulfate, sodium laurylbenzene sulfonate, styrene-maleic anhydride copolymer, and fatty alcohol polyoxyethylene. The silane-modified polyether polyether is selected from one or more of the following: sorbitan polyoxyethylene polyoxypropylene ether, sorbitan monostearate polyoxyethylene ether, polyvinyl alcohol, polycarboxylate, and naphthalene sulfonate; the silane-modified polyether polycondensation inhibitor is selected from at least one of ethylene glycol, ethanol, isopropanol, phosphoric acid, and citric acid; the acidic pH adjuster is selected from at least one of formic acid, acetic acid, hydrochloric acid, phosphoric acid, sulfuric acid, lactic acid, citric acid, malic acid, tartaric acid, and salicylic acid; the catalyst is an amine or tin-based catalyst, selected from trialkylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, etc. At least one of the following: amine, m-phenylenediamine, triethanolamine, diethanolamine, monoethanolamine, stannous octoate, tin butyrate, dibutyltin diacetate, dibutyltin dioctanoate, chelated tin, and dibutyltin dilaurate; the alkaline pH adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, sodium bicarbonate, ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, and monoethanolamine; the defoamer is selected from at least one of amides, organosilicones, polyethers, and polyether-modified polysiloxanes; the dispersant... The thickener is selected from one or more of polycarboxylates, sulfates, sulfonates, lignin sulfonates, and block polyethers; preferably, the thickener is selected from one or more of magnesium aluminum silicate, xanthan gum, polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose, bentonite, and silica; preferably, the preservative is selected from one or more of sodium benzoate, Kathon, BHT, potassium sorbate, methylparaben, sodium diacetate, calcium propionate, and sodium lactate; preferably, the antifreeze is selected from one or more of ethylene glycol, propylene glycol, glycerol, and urea.

4. A method for preparing the high-efficiency cyhalothrin nanocapsule suspension according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolve the active ingredient, high-efficiency cyhalothrin, in a solvent and add silane-modified polyether as the first mixture; (2) Mix water, silane-modified polyether inhibitor, emulsifier and defoamer, add acidic pH adjuster to adjust pH value to 3-5, and form a second mixture; (3) The first mixture is added dropwise to the second mixture, and high-speed shear emulsification is performed to form a high-efficiency cyhalothrin nanoemulsion; (4) Heat the high-efficiency cyhalothrin nanoemulsion obtained in step (3) to 40-70 ℃, add catalyst and alkaline pH adjuster to adjust pH≥7, so that the silane modified polyether is cured, and then keep it at 40-70 ℃ for 2-4 h. After the heat preservation is completed, cool it down to 20-30 ℃. (5) Add dispersant, thickener, preservative and antifreeze to the material obtained in step (4) to obtain the high-efficiency cyhalothrin nanocapsule suspension.

5. The method according to claim 4, characterized in that, The active ingredient, lambda-cyhalothrin, has a content of 10-30%, preferably 15-25%, and even more preferably 23%. The solvent is selected from at least one of 100# solvent oil, 150# solvent oil, 200# solvent oil, cyclohexanone, xylene, isoflurane, methyl oleate, soybean oil, and ethyl acetate; the emulsifier is selected from castor oil polyoxyethylene ether, nonylphenol polyoxyethylene ether, block polyethers, sodium lignosulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, styrene-maleic anhydride copolymer, fatty alcohol polyoxyethylene ether, sorbitan polyoxyethylene polyoxypropylene ether, and sorbitan monostearate polyoxyethylene ether. The silane-modified polyether polycondensation inhibitor is selected from at least one of ethylene glycol, ethanol, isopropanol, phosphoric acid, and citric acid; the acidic pH adjuster is selected from at least one of formic acid, acetic acid, hydrochloric acid, phosphoric acid, sulfuric acid, lactic acid, citric acid, malic acid, tartaric acid, and salicylic acid; the catalyst is an amine or tin-based catalyst, selected from trialkylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, and monoethanolamine. The alkaline pH adjuster is selected from at least one of the following: stannous octoate, stannous butyrate, dibutyltin diacetate, dibutyltin dioctanoate, chelated stannous octoate, and dibutyltin dilaurate; the alkaline pH adjuster is selected from at least one of the following: sodium hydroxide, potassium hydroxide, sodium bicarbonate, ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine, m-phenylenediamine, triethanolamine, diethanolamine, monoethanolamine, etc.; the defoamer is selected from at least one of the following: amides, organosilicones, polyethers, and polyether-modified polysiloxanes; the dispersant is selected from polycarboxylates and sulfates. The thickener is selected from one or more of magnesium aluminum silicate, xanthan gum, polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose, bentonite, and silica; preferably, the preservative is selected from one or more of sodium benzoate, Kathon, BHT, potassium sorbate, methylparaben, sodium diacetate, calcium propionate, and sodium lactate; preferably, the antifreeze is selected from one or more of ethylene glycol, propylene glycol, glycerol, and urea.

6. The method for preparing the high-efficiency cyhalothrin nanocapsule suspension according to any one of claims 4-5, characterized in that, Before high-speed shear emulsification to form a highly efficient cyhalothrin nanoemulsion, a silane-modified polyether condensation inhibitor is added to the second mixture, and the pH is adjusted to 3-5 to inhibit the curing of the silane-modified polyether upon contact with water.

7. The method for preparing the high-efficiency cyhalothrin nanocapsule suspension according to any one of claims 4-6, characterized in that, After high-efficiency cyhalothrin nanoemulsion is formed by high-speed shear emulsification, the silane-modified polyether is cured by at least one of the following methods: increasing the temperature, adding a catalyst, or adjusting the pH of the system to ≥7.

8. The high-efficiency cyhalothrin nanocapsules according to claim 1, characterized in that, The average particle size of the nanocapsules is 100~400nm.

9. The application of the high-efficiency cyhalothrin nanocapsule suspension according to any one of claims 1-3 or the high-efficiency cyhalothrin nanocapsule suspension prepared by the preparation method according to any one of claims 4-8, characterized in that, It can be applied to crops to kill or control pests.

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