Efficient lambda-cyhalothrin microcapsule suspending agent and preparation method thereof

Abstract

The application relates to the technical field of pesticide preparations, in particular to a lambda-cyhalothrin microcapsule suspending agent and a preparation method thereof; the lambda-cyhalothrin microcapsule suspending agent comprises the following raw material components in mass fractions: 10-25 parts of lambda-cyhalothrin, 1-2 parts of octyl amine alginate, 6-9 parts of an emulsifier, 5-10 parts of a solvent, 1-2 parts of a compound additive, 1-2 parts of a wetting agent, 2-3 parts of a dispersing agent, 0.5-1 part of a thickening agent, 0.2-0.8 parts of an antifreezing agent and 40-115 parts of water; through the synergistic effect of the octyl amine alginate and the compound additive, in combination with an optimized emulsification system and a preparation process, the lambda-cyhalothrin is efficiently encapsulated, the prepared lambda-cyhalothrin microcapsule suspending agent has good encapsulation rate, drug loading, high suspending rate, thermal storage stability and cold storage stability, and the preparation performance is excellent.

Description

Technical Field

[0001] This application relates to the technical field of pesticide formulations, and in particular to a highly efficient cyhalothrin microcapsule suspension and its preparation method. Background Technology

[0002] High-efficiency cyhalothrin is a broad-spectrum pyrethroid insecticide that works by acting on the insect's nervous system, interfering with sodium ion channel transmission, and blocking nerve impulse transmission, thereby achieving its insecticidal effect. It has excellent control effects on various agricultural and forestry pests, such as vegetable pests, wheat pests, and fruit tree pests. With its broad insecticidal spectrum and rapid knockdown speed, it is a widely used technical grade insecticide in agricultural production. However, high-efficiency cyhalothrin technical grade has several shortcomings in practical applications, greatly limiting its effectiveness and application scenarios: the technical grade is prone to hydrolysis and photodegradation, and after field application, it is easily degraded rapidly by sunlight and rainwater, resulting in a short residual effect; at the same time, the agent has high toxicity to aquatic organisms, easily causing residual pollution in water bodies after field application, resulting in poor ecological safety; in addition, its low melting point and multiple crystal structures make it prone to physical instability problems such as crystal growth and stratification when directly preparing conventional suspensions, leading to poor storage stability of the formulation.

[0003] Microencapsulated suspensions are novel environmentally friendly pesticide formulations that encapsulate the active ingredients of pesticides within a polymeric capsule wall material, forming micron-sized microcapsules that are uniformly dispersed in an aqueous phase. This microencapsulation technology is adaptable to the encapsulation modification of both solid and liquid pesticide technical materials. Utilizing the physical barrier protection and slow-release function of the capsule wall, it effectively isolates the technical material from external environmental factors such as light, moisture, and temperature, while achieving controlled and long-lasting release of the pesticide. Processing high-efficiency cyhalothrin technical material into microencapsulated suspensions can fundamentally solve the application defects of technical materials and conventional formulations, effectively slowing down the degradation rate of the active ingredient in the environment and significantly extending its field retention period. Simultaneously, the capsule wall prevents the active ingredient from directly contacting water bodies and non-target organisms, significantly reducing the toxicity of the pesticide to aquatic organisms and improving ecological safety. Furthermore, the formulation uses water as a medium, eliminating the need for large amounts of organic solvents, making it green and environmentally friendly. It also thoroughly improves the layering and precipitation problems caused by the unstable crystal form of the technical material, enhancing the overall physical stability of the formulation.

[0004] Currently, there are several high-efficiency cyhalothrin microcapsule suspensions and research reports on them. However, existing commercial formulations and technologies still have significant shortcomings, making it difficult to meet the high-quality and high-efficiency pesticide application needs of modern green agriculture. Firstly, the capsule wall formulations and preparation processes of existing high-efficiency cyhalothrin microcapsule suspensions are not perfect. The capsule wall density and mechanical strength are generally insufficient. During high-temperature storage and transportation, the capsule wall is prone to damage and permeation, leading to leakage and decomposition of the internal active ingredients, resulting in a high rate of active ingredient loss. The product's thermal storage stability and room temperature storage stability are difficult to meet standards, easily leading to problems such as efficacy attenuation and formulation deterioration. Secondly, the encapsulation rate of existing products is generally low. A large amount of high-efficiency cyhalothrin active ingredient cannot be effectively encapsulated and exists in a free state in the aqueous phase. This not only significantly reduces the effective pesticide loading of the formulation and weakens the insecticidal efficacy in the field, but also causes the free pesticide to directly contact the external environment, increasing the risk of residues in water and soil, and reducing product safety and utilization. Furthermore, existing microcapsule suspensions have poor slow-release regulation performance, and the release rate from the capsule wall is uncontrollable. In the early stage after application, the rapid release of the pesticide can easily cause phytotoxicity, and in the later stage, the effective ingredients are quickly depleted. The overall duration of effectiveness still does not meet the requirements for long-term pest control, and farmers need to apply the pesticide repeatedly, which not only increases the cost of pesticides and labor, but also aggravates the pesticide residue pollution in farmland.

[0005] In summary, developing a high-efficiency cyhalothrin microcapsule suspension with high encapsulation efficiency, excellent suspension stability, superior thermal storage performance, controllable sustained-release effect, and long-lasting effect, along with its preparation method, can effectively overcome the technical bottlenecks of existing formulations, enhance the application performance and market value of high-efficiency cyhalothrin formulations, and has significant practical significance and industrial application value for promoting pesticide reduction and efficiency improvement and the development of green agriculture. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides a highly efficient cyhalothrin microcapsule suspension and its preparation method.

[0007] In a first aspect, this application provides a highly efficient cyhalothrin microcapsule suspension, employing the following technical solution: A high-efficiency cyhalothrin microcapsule suspension comprises the following raw material components in parts by weight: 10-25 parts of high-efficiency cyhalothrin, 1-2 parts of alginate octamide, 6-9 parts of emulsifier, 5-10 parts of solvent, 1-2 parts of compounding agent, 1-2 parts of wetting agent, 2-3 parts of dispersant, 1.8-2.5 parts of inorganic salt, 0.5-1 part of thickener, 0.2-0.8 parts of antifreeze agent, and 40-115 parts of water.

[0008] By adopting the above technical solution, this application effectively overcomes the defects of high-efficiency cyhalothrin technical material, such as easy photodegradation, easy hydrodegradation, and high toxicity to aquatic organisms, through microencapsulation technology. By using alginate octamide as the encapsulation material to construct a stable microcapsule structure, it not only significantly improves the physicochemical stability of the formulation and achieves sustained-release and controlled-release of active ingredients to prolong the duration of efficacy, but also uses water as the main dispersion medium, reducing the use of organic solvents. Furthermore, microcapsules can reduce the direct exposure of active ingredients in water. While improving pesticide utilization and control effect, it also has the comprehensive beneficial effects of being environmentally friendly and enhancing the safety of use.

[0009] The dispersant added in this application effectively inhibits the aggregation and Austaunch ripening of microcapsule particles due to its steric hindrance and electrostatic repulsion effect, ensuring that the system maintains excellent suspension stability during long-term storage. Meanwhile, the inorganic salt in a specific ratio precisely controls the osmotic pressure of the aqueous phase, which not only prevents the capsule skin from shrinking or rupturing due to the imbalance of internal and external osmotic pressure, but also acts as an electrolyte to compress the double layer on the surface of the microcapsules, further enhancing physical stability. The two work together to ensure that the microcapsule suspension has a uniform particle size distribution, good flowability, and long-lasting sustained-release performance.

[0010] Preferably, the dispersant comprises at least one selected from tristyrene-phenol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether phosphate, ammonium salt of tristyrene-phenol polyoxyethylene ether phosphate, naphthalene sulfonate formaldehyde condensate sulfonate, succinate sulfonate, sodium lignosulfonate, calcium lignosulfonate, and sodium polycarboxylate.

[0011] Preferably, the inorganic salt includes at least one of magnesium aluminum silicate, sodium sulfate, sodium chloride, disodium hydrogen phosphate, magnesium chloride, magnesium sulfate, and barium sulfate.

[0012] Preferably, the compound additive comprises the following raw material components in parts by weight: 20-40 parts of nano-calcium carbonate, 0.5-2 parts of L-lysine, 0.5-1.5 parts of nano-hydroxyapatite, 0.1-0.5 parts of chitosan oligosaccharide, and 0.5-1.5 parts of silane coupling agent.

[0013] Preferably, the preparation method of the compound additive includes the following steps: Nano-calcium carbonate and water are mixed to obtain a nano-calcium carbonate suspension with a solid content of 10%. A nano-calcium carbonate suspension with a solid content of 10% was heated to 60-70℃, L-lysine was added and mixed, then nano-hydroxyapatite and silane coupling agent were added and mixed, chitosan oligosaccharide was added and mixed, filtered and dried to obtain the compound additive.

[0014] By adopting the above technical solution, this application further improves the overall performance of the formulation while ensuring microcapsule formation through the synergistic combination of compounded adjuvants, emulsifiers and solvents. Among them, the compound adjuvant abandons the traditional single inert filler approach, using nano-calcium carbonate and nano-hydroxyapatite as inorganic functional carriers. Nano-calcium carbonate, with its nanoscale effect, can not only enhance the physical stability of the system as a dispersed phase, but also increase the retention and spreading area of ​​the pesticide on the leaf surface after application. The porous structure of nano-hydroxyapatite provides physical adsorption space for high-efficiency cyhalothrin, which helps to delay release and reduce burst release. Chitosan oligosaccharide, as a plant immune inducer, can synergistically enhance crop stress resistance and form a functional complement with insecticidal action, which helps to enhance the overall health of crops. The added silane coupling agent improves the interfacial compatibility between inorganic powder and organic system, avoiding performance degradation caused by nanoparticle agglomeration. Moreover, the preparation method of each raw material adopts a stepwise mixing method, first allowing nano-calcium carbonate to fully contact L-lysine before introducing the other components, which is conducive to the uniform dispersion of each functional unit and synergistic effect.

[0015] This formulation, through the functional design and precise formulation of auxiliary components, significantly improves the microencapsulated suspension in multiple aspects such as sustained release, controlled release, and storage stability. The technical solution is complete and has a prominent synergistic effect.

[0016] Preferably, the emulsifier includes at least one of styrene-based phenolic polyoxyethylene ether, calcium dodecylbenzenesulfonate, and emulsifier 0201B.

[0017] More preferably, the emulsifier is a mixture of styrene-based phenol polyoxyethylene ether and calcium dodecylbenzenesulfonate.

[0018] More preferably, the mass ratio of the styrene-based phenol polyoxyethylene ether to calcium dodecylbenzenesulfonate is (1-3):1.

[0019] Preferably, the solvent includes at least one of S-200# solvent, S-150# solvent, and xylene.

[0020] By adopting the above technical solution, in the emulsification and dissolution system, the added emulsifier molecules are arranged in an orderly manner at the oil-water interface to form a dense and flexible interfacial film. This not only ensures that the oil droplet size is uniform and fine during emulsification, but also effectively inhibits Austronesian ripening and aggregation during long-term storage, giving the formulation excellent thermal storage stability and dilution stability. The added solvent has strong dissolving power and moderate volatility, which can ensure that the active ingredient remains dissolved inside the microcapsule without crystallization, avoiding the decrease in efficacy and damage to the capsule wall caused by crystal transformation.

[0021] Secondly, this application provides a method for preparing a highly efficient cyhalothrin microcapsule suspension, employing the following technical solution: Add emulsifier, dispersant, wetting agent, compounding agent and inorganic salt to water, heat to 50-55℃, stir for 30-60 minutes to form aqueous solution A; Maintain the temperature at 45-55℃, add high-efficiency cyhalothrin and solvent to aqueous solution A, and disperse by high-speed shearing to form drug-containing emulsion B; Alginate octamide was dissolved in water to prepare wall material solution C; While stirring, add wall material solution C dropwise to emulsion B. After the addition is complete, keep the temperature at 50-55℃ for 60 minutes to allow octyl alginate to form a capsule shell at the oil-water interface. Cool the mixture to below 35°C, add antifreeze and thickener, and mix to obtain a high-efficiency cyhalothrin microcapsule suspension.

[0022] By adopting the above technical solution, this application pre-prepares an alginate octamide solution and then adds it dropwise to a premixed solution. This encapsulates the lambda-cyhalothrin within the capsule wall, effectively isolating it from the direct effects of external light, heat, and moisture. This overcomes the drawbacks of traditional water-in-oil emulsions or emulsifiable concentrates, such as poor physical stability due to crystallization and paste formation. Simultaneously, the microcapsule structure imparts sustained-release and controlled-release properties to the active ingredient, extending its duration of action and reducing the frequency of application. The capsule wall itself protects the active ingredient, significantly enhancing the lambda-cyhalothrin microcapsule suspension's resistance to UV photolysis and rain erosion, reducing the ineffective loss of the active ingredient due to environmental factors, and further mitigating potential risks to non-target organisms and the aquatic environment. Furthermore, this method does not require complex interfacial polymerization reactions or high-temperature, high-pressure conditions; microencapsulation can be achieved simply through dropwise mixing. The operation is simple and the process is mild, avoiding the impact of shear heat on material quality. It has a low threshold for industrialization and good production feasibility.

[0023] Thirdly, this application provides an application of a highly efficient cyhalothrin microcapsule suspension in the control of lepidopteran pests, employing the following technical solution: Application of a highly efficient cyhalothrin microcapsule suspension or a highly efficient cyhalothrin microcapsule suspension prepared by the above method in the control of lepidopteran pests.

[0024] Lepidoptera pests such as diamondback moth, cotton bollworm, and beet armyworm.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. This application utilizes the synergistic effect of alginate octamide and compound adjuvants, combined with an optimized emulsification system and preparation process, to form a dense and complete microcapsule wall structure, achieving efficient encapsulation of high-efficiency cyhalothrin. The resulting high-efficiency cyhalothrin microcapsule suspension exhibits excellent encapsulation rate, drug loading, high suspension rate, thermal and cold storage stability, and superior formulation performance. 2. The high-efficiency cyhalothrin microcapsule suspension prepared in this application has good sustained-release properties. After application, it can continuously release the active ingredients and has a long duration of effect, which can reduce the number of field applications and reduce agricultural production costs and labor intensity. Detailed Implementation

[0026] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0027] All raw materials involved in this application are commercially available products, among which, Nano-calcium carbonate, purchased from Ningbo Jiufeng Nano New Energy Co., Ltd., with an average particle size of 0.03 micrometers; L-Lysine was purchased from Sinopharm Chemical Reagent Co., Ltd. Nano-hydroxyapatite, purchased from Beijing Deco Island Gold Technology Co., Ltd., with a particle size of 20-30nm; Chitosan oligosaccharide was purchased from Xi'an Keleli Biotechnology Co., Ltd. Styrene-based phenolic polyoxyethylene ether, purchased from Nantong Chenrun Chemical Co., Ltd., specification 602, HLB>17; Calcium dodecylbenzenesulfonate was purchased from Jinan Haohua Industrial Co., Ltd. Ordinary calcium carbonate and light calcium carbonate were purchased from Zibo Hainuo Chemical Plant. Sodium alginate, CAS No.: 9005-38-3, purchased from Maclean's; The present application will be further described in detail below with reference to embodiments and comparative examples.

[0028] Raw material source:

[0029] 230 mL of ultrapure water and 5 g of sodium alginate were mixed and heated to 35 °C with stirring until completely dissolved. 1.21 g of EDC·HCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) was added, and the pH of the solution was adjusted to 3.4 using 0.5 mol / L HCl in an ice-water bath. The reaction was activated at 35 °C for 10 minutes. Subsequently, 8.45 mL of octylamine was added dropwise to the reaction system to form an emulsion. The ice-water bath was removed, and the reaction was carried out at 35 °C with continuous mechanical stirring for 24 hours.

[0030] After the reaction was complete, the product was poured into anhydrous ethanol to precipitate the precipitate. The precipitate was then centrifuged at 5000 rpm, collected, and washed twice with anhydrous ethanol. The washed precipitate was placed in a constant-temperature drying oven and dried at 60°C to constant weight to obtain the amphiphilic polymeric surfactant octamide alginate.

[0031] Preparation Example 1:

[0032] The compound additives include the following raw material components: 30 kg of nano calcium carbonate, 1.2 kg of L-lysine, 1 kg of nano hydroxyapatite, 0.3 kg of chitosan oligosaccharide, and 1 kg of silane coupling agent KH-550.

[0033] The preparation method of the compound additives is as follows: Step 1: Preparation of the pre-dispersion Nano-calcium carbonate was mixed with deionized water to obtain a nano-calcium carbonate suspension with a solid content of 10%. Nano-hydroxyapatite and 5 kg of deionized water were mixed and ultrasonically dispersed for 30 min to obtain a uniform nano-hydroxyapatite suspension. Chitosan oligosaccharide was dissolved in a dilute acetic acid solution (1 wt%) and stirred for 10 minutes to obtain a chitosan oligosaccharide solution with a 2.5 wt% mass fraction.

[0034] Mix silane coupling agent KH-550 with 5 kg of deionized water, adjust the pH to 4.5 with acetic acid, and let stand for 20 min to hydrolyze to obtain silane coupling agent hydrolysate.

[0035] Step 2: Preparation of compound additives A nano-calcium carbonate suspension with a solid content of 10% was heated to 70°C, and L-lysine was added and mixed for 2 hours to obtain a mixture. Nano-hydroxyapatite suspension was added to the mixture and stirred at 300 rpm for 30 minutes. Silane coupling agent hydrolysate was added dropwise. After the addition was complete, the mixture was stirred for 1.5 hours. Chitosan oligosaccharide solution was added and stirred at 300 rpm for 30 minutes. After the reaction was complete, heating was stopped, and the mixture was filtered. The filter cake was collected and washed three times with deionized water until the pH of the washing solution was neutral and there was no acetic acid residue. The washed filter cake was placed in a vacuum drying oven and dried at 80℃ and a vacuum of -0.09 MPa for 4 hours to obtain the compounded additive.

[0036] Preparation Example 2:

[0037] The compound additives include the following raw material components: 20 kg of nano calcium carbonate, 0.5 kg of L-lysine, 0.5 kg of nano hydroxyapatite, 0.1 kg of chitosan oligosaccharide, and 0.5 kg of silane coupling agent KH-550.

[0038] The preparation method of the compound additives is as follows: Step 1: Preparation of the pre-dispersion Nano-calcium carbonate was mixed with deionized water to obtain a nano-calcium carbonate suspension with a solid content of 10%. Nano-hydroxyapatite and 5 kg of deionized water were mixed and ultrasonically dispersed for 30 min to obtain a uniform nano-hydroxyapatite suspension. Chitosan oligosaccharide was dissolved in a dilute acetic acid solution (1 wt%) and stirred for 10 minutes to obtain a chitosan oligosaccharide solution with a 2.5 wt% mass fraction.

[0039] Mix silane coupling agent KH-550 with 5 kg of deionized water, adjust the pH to 4.5 with acetic acid, and let stand for 20 min to hydrolyze to obtain silane coupling agent hydrolysate.

[0040] Step 2: Preparation of compound additives A nano-calcium carbonate suspension with a solid content of 10% was heated to 70°C, and L-lysine was added and mixed for 2 hours to obtain a mixture. Nano-hydroxyapatite suspension was added to the mixture and stirred at 300 rpm for 30 minutes. Silane coupling agent hydrolysate was added dropwise. After the addition was complete, the mixture was stirred for 1.5 hours. Chitosan oligosaccharide solution was added and stirred at 300 rpm for 30 minutes. After the reaction was complete, heating was stopped, and the mixture was filtered. The filter cake was collected and washed three times with deionized water until the pH of the washing solution was neutral and there was no acetic acid residue. The washed filter cake was placed in a vacuum drying oven and dried at 80℃ and a vacuum of -0.09 MPa for 4 hours to obtain the compounded additive.

[0041] Preparation Example 3:

[0042] The compound additives include the following raw material components: 40 kg of nano calcium carbonate, 2 kg of L-lysine, 1.5 kg of nano hydroxyapatite, 0.5 kg of chitosan oligosaccharide, and 1.5 kg of silane coupling agent KH-550.

[0043] The preparation method of the compound additives is as follows: Step 1: Preparation of the pre-dispersion Nano-calcium carbonate was mixed with deionized water to obtain a nano-calcium carbonate suspension with a solid content of 10%. Nano-hydroxyapatite and 5 kg of deionized water were mixed and ultrasonically dispersed for 30 min to obtain a uniform nano-hydroxyapatite suspension. Chitosan oligosaccharide was dissolved in a dilute acetic acid solution (1 wt%) and stirred for 10 minutes to obtain a chitosan oligosaccharide solution with a 2.5 wt% mass fraction.

[0044] Mix silane coupling agent KH-550 with 5 kg of deionized water, adjust the pH to 4.5 with acetic acid, and let stand for 20 min to hydrolyze to obtain silane coupling agent hydrolysate.

[0045] Step 2: Preparation of compound additives A nano-calcium carbonate suspension with a solid content of 10% was heated to 70°C, and L-lysine was added and mixed for 2 hours to obtain a mixture. Nano-hydroxyapatite suspension was added to the mixture and stirred at 300 rpm for 30 minutes. Silane coupling agent hydrolysate was added dropwise. After the addition was complete, the mixture was stirred for 1.5 hours. Chitosan oligosaccharide solution was added and stirred at 300 rpm for 30 minutes. After the reaction was complete, heating was stopped, and the mixture was filtered. The filter cake was collected and washed three times with deionized water until the pH of the washing solution was neutral and there was no acetic acid residue. The washed filter cake was placed in a vacuum drying oven and dried at 80℃ and a vacuum of -0.09 MPa for 4 hours to obtain the compounded additive.

[0046] Example 1:

[0047] A high-efficiency cyhalothrin microcapsule suspension comprises the following raw material components: 17.5 kg of high-efficiency cyhalothrin, 1.5 kg of alginate octamide, 7.5 kg of emulsifier, 7.5 kg of solvent, 1.5 kg of compounding agent, 1.5 kg of wetting agent, 2.5 kg of dispersant, 2.1 kg of inorganic salt, 0.75 kg of thickener, 0.5 kg of antifreeze agent, and 60.25 kg of water.

[0048] The emulsifier is a mixture of 5.63 kg of styrene-based phenol polyoxyethylene ether and 1.87 kg of calcium dodecylbenzenesulfonate.

[0049] The solvent is S-150# solvent.

[0050] The compound additive was prepared in Preparation Example 1.

[0051] The wetting agent is wetting agent SP-6821.

[0052] The dispersant is sodium lignosulfonate.

[0053] The inorganic salt is a mixture of magnesium aluminum silicate and sodium chloride, with a mass ratio of 2:1.

[0054] The thickener is xanthan gum.

[0055] The antifreeze is ethylene glycol.

[0056] A method for preparing a highly efficient cyhalothrin microcapsule suspension comprises the following steps: Emulsifier, dispersant, wetting agent, compounding agent and inorganic salt are added to water, placed in a high shear emulsifier, heated to 55°C, and sheared and stirred at 1500 r / min for 30 minutes to form aqueous solution A; Keep the temperature at 55℃, add high-efficiency cyhalothrin technical and solvent to aqueous solution A, and continue to shear and stir at 1500 r / min for 20 minutes to form drug-containing emulsion B; Alginate octamide was dissolved in water to prepare wall material solution C; Maintain the temperature of emulsion B at 55℃, and add wall material solution C dropwise to emulsion B at a rate of 5mL / min. During the dropwise addition, maintain a high-speed shear of 800r / min. After the dropwise addition is completed, keep the temperature at 55℃ for 60 minutes to allow alginate octamide to form a capsule shell at the oil-water interface. The reaction system was cooled to 30°C, and antifreeze and thickener were added. The mixture was then slowly stirred at 200 r / min for 30 minutes to obtain a high-efficiency cyhalothrin microcapsule suspension.

[0057] Example 2:

[0058] A high-efficiency cyhalothrin microcapsule suspension comprises the following raw material components: 10 kg of high-efficiency cyhalothrin, 1 kg of alginate octamide, 6 kg of emulsifier, 5 kg of solvent, 1 kg of compounding agent, 1 kg of wetting agent, 2 kg of dispersant, 1.8 kg of inorganic salt, 0.5 kg of thickener, 0.2 kg of antifreeze, and 73.3 kg of water.

[0059] The emulsifier is a mixture of 4.5 kg of styrene-based phenol polyoxyethylene ether and 1.5 kg of calcium dodecylbenzenesulfonate.

[0060] The solvent is S-150# solvent.

[0061] The compound additive was prepared in Preparation Example 2.

[0062] The wetting agent is wetting agent SP-6821.

[0063] The dispersant is sodium lignosulfonate.

[0064] The inorganic salt is a mixture of magnesium aluminum silicate and sodium chloride, with a mass ratio of 2:1.

[0065] The thickener is xanthan gum.

[0066] The antifreeze is ethylene glycol.

[0067] A method for preparing a highly efficient cyhalothrin microcapsule suspension comprises the following steps: Emulsifier, dispersant, wetting agent, compounding agent and inorganic salt are added to water, placed in a high shear emulsifier, heated to 55°C, and sheared and stirred at 1500 r / min for 30 minutes to form aqueous solution A; Keep the temperature at 55℃, add high-efficiency cyhalothrin technical and solvent to aqueous solution A, and continue to shear and stir at 1500 r / min for 20 minutes to form drug-containing emulsion B; Alginate octamide was dissolved in water to prepare wall material solution C; Maintain the temperature of emulsion B at 55℃, and add wall material solution C dropwise to emulsion B at a rate of 5mL / min. During the dropwise addition, maintain a high-speed shear of 800r / min. After the dropwise addition is completed, keep the temperature at 55℃ for 60 minutes to allow alginate octamide to form a capsule shell at the oil-water interface. The reaction system was cooled to 30°C, and antifreeze and thickener were added. The mixture was then slowly stirred at 200 r / min for 30 minutes to obtain a high-efficiency cyhalothrin microcapsule suspension.

[0068] Example 3:

[0069] A high-efficiency cyhalothrin microcapsule suspension comprises the following raw material components: 25 kg of high-efficiency cyhalothrin, 2 kg of alginate octamide, 9 kg of emulsifier, 10 kg of solvent, 2 kg of compounding agent, 2 kg of wetting agent, 3 kg of dispersant, 2.5 kg of inorganic salt, 1 kg of thickener, 0.8 kg of antifreeze agent, and 45.2 kg of water.

[0070] The emulsifier is a mixture of 6.75 kg of styrene-based phenol polyoxyethylene ether and 2.25 kg of calcium dodecylbenzenesulfonate.

[0071] The solvent is S-150# solvent.

[0072] The compound additive was prepared in Preparation Example 3.

[0073] The wetting agent is wetting agent SP-6821.

[0074] The dispersant is sodium lignosulfonate.

[0075] The inorganic salt is a mixture of magnesium aluminum silicate and sodium chloride, with a mass ratio of 2:1.

[0076] The thickener is xanthan gum.

[0077] The antifreeze is ethylene glycol.

[0078] A method for preparing a highly efficient cyhalothrin microcapsule suspension comprises the following steps: Emulsifier, dispersant, wetting agent, compounding agent and inorganic salt are added to water, placed in a high shear emulsifier, heated to 55°C, and sheared and stirred at 1500 r / min for 30 minutes to form aqueous solution A; Keep the temperature at 55℃, add high-efficiency cyhalothrin technical and solvent to aqueous solution A, and continue to shear and stir at 1500 r / min for 20 minutes to form drug-containing emulsion B; Alginate octamide was dissolved in water to prepare wall material solution C; Maintain the temperature of emulsion B at 55℃, and add wall material solution C dropwise to emulsion B at a rate of 5mL / min. During the dropwise addition, maintain a high-speed shear of 800r / min. After the dropwise addition is completed, keep the temperature at 55℃ for 60 minutes to allow alginate octamide to form a capsule shell at the oil-water interface. The reaction system was cooled to 30°C, and antifreeze and thickener were added. The mixture was then slowly stirred at 200 r / min for 30 minutes to obtain a high-efficiency cyhalothrin microcapsule suspension.

[0079] Comparative Example 1:

[0080] The difference from Example 1 is that no compound additives are added.

[0081] Comparative Example 2:

[0082] The difference from Example 1 is that L-lysine is not added during the preparation of the compound additive.

[0083] Comparative Example 3:

[0084] The difference from Example 1 is that ordinary calcium carbonate is used instead of nano calcium carbonate in the process of preparing the compound additive.

[0085] Comparative Example 4:

[0086] The difference from Example 1 is that the compounding agent is replaced with an equal weight of compounding agent prepared by the following method.

[0087] This compound additive includes the following raw material components: 1 kg of nano hydroxyapatite and 0.3 kg of chitosan oligosaccharide.

[0088] Nano-hydroxyapatite and 5 kg of deionized water were mixed and ultrasonically dispersed for 30 min to obtain a uniform nano-hydroxyapatite suspension. Chitosan oligosaccharide was dissolved in a dilute acetic acid solution (1 wt%) and stirred for 10 minutes to obtain a chitosan oligosaccharide solution with a 2.5 wt% mass fraction. The nano-hydroxyapatite suspension was mixed with the chitosan oligosaccharide solution and stirred at 300 r / min for 30 minutes. The mixture was then filtered, and the filter cake was collected and washed three times with deionized water until the pH of the washing solution was neutral and there was no acetic acid residue. The washed filter cake was placed in a vacuum drying oven and dried at 80℃ and a vacuum of -0.09 MPa for 4 hours. The mixture was then ground to obtain the compounded additive.

[0089] Performance testing:

[0090] 1. Performance test results of high-efficiency cyhalothrin microcapsule suspension The performance of the high-efficiency cyhalothrin microcapsule suspensions prepared in the above examples and comparative examples was tested, and the test results are shown in the table.

[0091] Suspension rate: Test method CIPAC MT 184; Cold storage experiment: Test method CIPAC MT 39.3; Thermal storage experiment: Test method CIPAC MT 46.3; Thermal storage experiment decomposition rate: Test method CIPAC MT 46.3; Table 1 Performance test results of high-efficiency cyhalothrin microcapsule suspension

[0092] As shown in Table 1, the high-efficiency cyhalothrin microcapsule suspension prepared in this application has good encapsulation rate, good suspension rate and good drug loading, and also has good cold storage stability and hot storage stability. All indicators are better than the reference standard.

[0093] Based on the test results of Example 1 and Comparative Example 1, it can be seen that the test results of Example 1 are better than those of Comparative Example 1, indicating that the addition of compound adjuvants can effectively improve the molding quality and system stability of cyhalothrin microcapsule suspension.

[0094] Based on the test results of Example 1 and Comparative Example 2, it can be seen that the test results of Example 1 are better than those of Comparative Example 2. This indicates that Comparative Example 2 did not add L-lysine when preparing the additives, resulting in insufficient cross-linking density of the polymer network in the capsule wall and a relatively loose structure, which in turn reduced the suspension rate, encapsulation rate and thermal storage stability.

[0095] Based on the test results of Example 1 and Comparative Example 3, it can be seen that the test results of Example 1 are better than those of Comparative Example 3. This indicates that when ordinary calcium carbonate is used to replace nano-calcium carbonate, the micron-sized particles cannot be uniformly embedded in the pores of the capsule wall, making it difficult to exert the nanoscale enhancement effect. Instead, physical defects and leakage channels are formed in the capsule shell, resulting in poor dispersibility and interface enhancement effect, leading to a decrease in suspension rate, encapsulation rate, and thermal storage stability.

[0096] Based on the test results of Example 1 and Comparative Example 4, it can be seen that the test results of Example 1 are better than those of Comparative Example 4. This indicates that when nano-calcium carbonate is missing in the compound additive, the synergistic enhancement effect between the inorganic carrier and the capsule wall interface is weakened, resulting in a decrease in the strength of the microcapsule structure and thus a reduction in overall performance.

[0097] 2. Cumulative release rate Taking the oscillation method as an example, the specific steps for detecting the cumulative release rate are as follows: Accurately weigh the test sample containing approximately 5 mg of the active ingredient, place it in a 100 mL stoppered conical flask, add 100 mL of deionized water (pre-temperatured to (25±1)℃) as the release medium, immediately seal and start timing, place the conical flask in a constant temperature shaker and oscillate continuously at 100 r / min; at each preset sampling time point (e.g., 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 360, 420 min). Quickly pipette 2.0 mL of the supernatant release solution and immediately add 2.0 mL of fresh medium at the same temperature to maintain a constant total volume. After filtering the release solution through a 0.22 μm microporous membrane or centrifuging at high speed, discard the initial filtrate and collect the subsequent filtrate. Determine the concentration of the active ingredient using high performance liquid chromatography (HPLC) and calculate the dissolution amount at each time point based on the standard curve. Finally, calculate the cumulative release rate at each time point using the cumulative correction formula. Each sample group is measured in parallel three times, and the relative standard deviation should not exceed 5%. The average value is taken as the final result.

[0098] Table 2. Cumulative release rate of high-efficiency cyhalothrin microcapsule suspension

[0099] Throughout the entire release process, the cumulative release rate of the high-efficiency cyhalothrin microcapsule suspensions prepared in this application continued to increase with time, reaching or exceeding 97% at 420 min, indicating that each formulation has excellent sustained-release effect.

[0100] 3. Results of the investigation on the efficacy of high-efficiency cyhalothrin microcapsule suspension. To control the beet armyworm on cruciferous vegetables, the highly efficient cyhalothrin microcapsule suspension prepared in the above examples and comparative examples was used. For example, cabbage fields with beet armyworms in their 2nd-3rd instar were selected, with each plot measuring 20 square meters, arranged in a randomized block design. The test agent was diluted with water to a certain ratio, and each treatment was repeated 4 times. The solution was sprayed evenly using a backpack manual sprayer at a rate of 45 kg / mu.

[0101] Table 3. Results of the efficacy survey of high-efficiency cyhalothrin microcapsule suspension.

[0102] As can be seen from the table above, in the control of beet armyworm on cruciferous vegetables, the high-efficiency cyhalothrin microcapsule suspension prepared in this application showed high and stable control efficacy 14 days after application. This indicates that the high-efficiency cyhalothrin microcapsule suspension prepared in this application has good slow-release performance, can continuously release the active ingredient after application, has a long residual effect, can reduce the number of field applications, and reduce agricultural production costs and labor intensity.

[0103] Based on the test results of Example 1 and Comparative Example 1, it can be seen that the test results of Example 1 are better than those of Comparative Example 1. This indicates that without the addition of compound adjuvants, the formation and stability of microcapsules are significantly affected, which further affects the control effect of high-efficiency cyhalothrin microcapsule suspension on beet armyworm in cruciferous vegetables.

[0104] Based on the test results of Example 1 and Comparative Example 2, it can be seen that the test results of Example 1 are better than those of Comparative Example 2. This indicates that Comparative Example 2 did not add L-lysine when preparing the adjuvant, resulting in insufficient cross-linking density of the polymer network in the capsule wall and a relatively loose structure, which further affected the control effect of the high-efficiency cyhalothrin microcapsule suspension on the beet armyworm of cruciferous vegetables.

[0105] Based on the test results of Example 1 and Comparative Example 3, it can be seen that the test results of Example 1 are better than those of Comparative Example 3. This indicates that when ordinary calcium carbonate is used instead of nano calcium carbonate, the micron-sized particles cannot be uniformly embedded in the pores of the capsule wall. Instead, they form physical defects and leakage channels in the capsule shell, resulting in poor dispersibility and interface enhancement effect. This further affects the control effect of the high-efficiency cyhalothrin microcapsule suspension on the beet armyworm of cruciferous vegetables.

[0106] Based on the test results of Example 1 and Comparative Example 4, it can be seen that the test results of Example 1 are better than those of Comparative Example 4. This indicates that the high-efficiency cyhalothrin microcapsule suspension prepared by using the alternative compound adjuvant constructed from nano-hydroxyapatite and chitosan oligosaccharide has a lower control efficacy against beet armyworm on cruciferous vegetables than that of Example 1.

Claims

1. A highly efficient cyhalothrin microcapsule suspension, characterized in that: The raw material components include the following parts by weight: 10-25 parts of high-efficiency cyhalothrin, 1-2 parts of alginate octamide, 6-9 parts of emulsifier, 5-10 parts of solvent, 1-2 parts of compounding agent, 1-2 parts of wetting agent, 2-3 parts of dispersant, 1.8-2.5 parts of inorganic salt, 0.5-1 part of thickener, 0.2-0.8 parts of antifreeze, and 40-115 parts of water.

2. The high-efficiency cyhalothrin microcapsule suspension according to claim 1, characterized in that: The dispersant comprises at least one of tristyrene-phenol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether phosphate, tristyrene-phenol polyoxyethylene ether phosphate ammonium salt, naphthalene sulfonate formaldehyde condensate sulfonate, succinate sulfonate, sodium lignosulfonate, calcium lignosulfonate, and sodium polycarboxylate.

3. The high-efficiency cyhalothrin microcapsule suspension according to claim 1, characterized in that: The inorganic salt includes at least one of magnesium aluminum silicate, sodium sulfate, sodium chloride, disodium hydrogen phosphate, magnesium chloride, magnesium sulfate, and barium sulfate.

4. The high-efficiency cyhalothrin microcapsule suspension according to claim 1, characterized in that: The compound additives include the following raw material components in parts by weight: 20-40 parts of nano-calcium carbonate, 0.5-2 parts of L-lysine, 0.5-1.5 parts of nano-hydroxyapatite, 0.1-0.5 parts of chitosan oligosaccharide, and 0.5-1.5 parts of silane coupling agent.

5. The high-efficiency cyhalothrin microcapsule suspension according to claim 4, characterized in that: The preparation method of the compound additive includes the following steps: Nano-calcium carbonate and water are mixed to obtain a nano-calcium carbonate suspension with a solid content of 10%. A nano-calcium carbonate suspension with a solid content of 10% was heated to 60-70℃, L-lysine was added and mixed, then nano-hydroxyapatite and silane coupling agent were added and mixed, chitosan oligosaccharide was added and mixed, filtered and dried to obtain the compound additive.

6. The high-efficiency cyhalothrin microcapsule suspension according to claim 1, characterized in that: The emulsifier includes at least one of styrene-based phenol polyoxyethylene ether, calcium dodecylbenzenesulfonate, and emulsifier 0201B.

7. The high-efficiency cyhalothrin microcapsule suspension according to claim 6, characterized in that: The emulsifier is a mixture of styrene-based phenol polyoxyethylene ether and calcium dodecylbenzene sulfonate; the mass ratio of styrene-based phenol polyoxyethylene ether to calcium dodecylbenzene sulfonate is (1-3):

1.

8. The high-efficiency cyhalothrin microcapsule suspension according to claim 1, characterized in that: The solvent includes at least one of S-200# solvent, S-150# solvent, and xylene.

9. A method for preparing the high-efficiency cyhalothrin microcapsule suspension according to any one of claims 1-8, characterized in that: The steps are as follows: Add emulsifier, dispersant, wetting agent, compounding agent and inorganic salt to water, heat to 50-55℃, stir for 30-60 minutes to form aqueous solution A; Maintain the temperature at 45-55℃, add high-efficiency cyhalothrin and solvent to aqueous solution A, and disperse by high-speed shearing to form drug-containing emulsion B; Alginate octamide was dissolved in water to prepare wall material solution C; While stirring, add wall material solution C dropwise to emulsion B. After the addition is complete, keep the temperature at 50-55℃ for 60 minutes to allow octyl alginate to form a capsule shell at the oil-water interface. Cool the mixture to below 35°C, add antifreeze and thickener, and mix to obtain a high-efficiency cyhalothrin microcapsule suspension.

10. The application of the high-efficiency cyhalothrin microcapsule suspension according to any one of claims 1-8 or the high-efficiency cyhalothrin microcapsule suspension prepared by the method of claim 9 in the control of lepidopteran pests.

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