Chlorpyrifos microemulsion and preparation method thereof

Abstract

The invention relates to the field of pesticides, and particularly discloses a chlorpyrifos microemulsion and a preparation method thereof. The invention relates to a chlorpyrifos microemulsion which comprises the following raw materials in percentage by mass: 20-50% of chlorpyrifos microcapsules, 8-15% of a nonionic surfactant, 12-18% of an anionic surfactant, 1-3% of a stabilizer and the balance of water, the chlorpyrifos microcapsule is of a structure with a core material wrapped by a wall material, and the raw materials comprise chlorpyrifos, epoxy fatty acid methyl ester, sodium alginate, cellulose filler and CaCl2. The chlorpyrifos microemulsion disclosed by the invention is applied to agricultural disease and pest control and has the advantages of lasting pesticide effect and excellent chemical stability.

Description

Technical Field

[0001] The present application relates to the field of pesticides, and more specifically, to a chlorpyrifos microemulsion and a preparation method thereof. Background Art

[0002] Pesticides, as important agricultural production materials, are crucial to preventing diseases and controlling pests and promoting stable and high yields of food and agriculture. The environmental friendliness and stability of pesticide formulations have always been the key to the development of the pesticide industry.

[0003] Chlorpyrifos, chemically known as O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) thiophosphate, is a broad-spectrum, highly effective, low-toxic, non-systemic organophosphorus insecticide with triple effects of stomach poison, contact killing and fumigation. It has good control effects on a variety of chewing and piercing-sucking mouthparts pests on rice, wheat, cotton, fruit trees, vegetables and tea trees. As a major variety that replaces highly toxic pesticides, chlorpyrifos has been at the forefront of global insecticides for many years.

[0004] However, the main formulation of traditional chlorpyrifos is emulsifiable concentrate, which mostly uses organic solvents as solvents, such as xylene and toluene. These organic solvents are highly volatile and have potential hazards to the environment and human health. Long-term use will lead to serious environmental pollution problems. With the increasing awareness of environmental protection and the growing demand for green pesticide formulations, chlorpyrifos microemulsions using water as solvent have gradually become a research hotspot. Water-based microemulsions can not only reduce environmental pollution, but also improve the safety and ease of use of pesticides.

[0005] With respect to the above-mentioned related technologies, the inventors have found that when the traditional emulsification process uses water as a solvent to prepare a chlorpyrifos microemulsion, it is often affected by improper selection of emulsifiers and imperfect emulsification processes, and it is difficult to fully meet the emulsification requirements for the preparation of the chlorpyrifos emulsifier, resulting in the poor stability of the prepared chlorpyrifos microemulsion, and easy precipitation and stratification during storage and transportation, thereby reducing the use effect and efficacy. Summary of the invention

[0006] In order to improve the chemical stability of the chlorpyrifos microemulsion and reduce the problems of stratification and precipitation, the present application provides a chlorpyrifos microemulsion and a preparation method thereof.

[0007] In the first aspect, the present application provides a chlorpyrifos microemulsion, which adopts the following technical solution: A chlorpyrifos microemulsion, wherein the raw materials include, by mass percentage, 20-50% of chlorpyrifos microcapsules, 8-15% of nonionic surfactants, 12-18% of anionic surfactants, 1-3% of stabilizers, and the balance is water; The chlorpyrifos microcapsule has a structure in which a core material is wrapped by a wall material, and the raw materials include chlorpyrifos, epoxy fatty acid methyl ester, sodium alginate, cellulose filler and CaCl2.

[0008] By adopting the above technical solution, using nonionic and anionic surfactants and stabilizers, it is more environmentally friendly than traditional organic solvents, reduces pollution to the environment, and conforms to the concept of sustainable development. The composite surfactant system has a better emulsification effect than two simple surfactants. Microencapsulating chlorpyrifos can obtain capsule particles with smaller and more uniform sizes. The wrapping of the wall material can significantly improve the compatibility of chlorpyrifos with the aqueous phase, thereby achieving a more uniform and stable dispersion; it can reduce the phenomenon of stratification or precipitation of the microemulsion caused by the incompatibility of chlorpyrifos with other components in the aqueous solution, so that chlorpyrifos can have better rheological properties in the formed microemulsion, effectively prevent the aggregation and sedimentation of chlorpyrifos in the aqueous phase, and improve the chemical stability of the chlorpyrifos microemulsion.

[0009] The wall material forms a protective layer on the surface of chlorpyrifos, which, on the one hand, reduces the direct exposure of chlorpyrifos and reduces the potential risk of environmental pollution. It can protect chlorpyrifos from high temperature during storage and transportation, improve the adaptability of chlorpyrifos microemulsion to environmental temperature and humidity, and avoid the reduction of efficacy due to external influences such as thermal decomposition. On the other hand, microencapsulation of chlorpyrifos can effectively reduce the volatilization loss of chlorpyrifos and realize slow release at the same time. It can be continuously released during the application process and improve the durability of the efficacy.

[0010] Optionally, the method for preparing the sustained-release microcapsules comprises the following steps: Chlorpyrifos and epoxy fatty acid methyl ester are mixed, and a core material solution is obtained after ultrasonic treatment; sodium alginate and cellulose filler are mixed evenly in a mass ratio of (7-16):(2.5-4.5), and mixed with water in a material-liquid ratio of 1:(7-10), and a wall material solution is obtained after ultrasonic treatment; Prepare 5-8% CaCl2 solution as receiving liquid, pass the core material solution and the wall material solution into the microfluidic chip respectively, form micro droplets in the chip through microfluidic technology, then collect and solidify in CaCl2 solution, and obtain after centrifugation.

[0011] By adopting the above technical scheme, sodium alginate has good film-forming property, gel property, biodegradability and biocompatibility. As the wall material of chlorpyrifos microcapsules, on the one hand, it can form a stable coating layer outside the chlorpyrifos, reduce the volatilization of chlorpyrifos and the direct contact of chlorpyrifos with the external environment, and effectively prevent the chemical reaction and physical degradation of chlorpyrifos from causing the decline of drug efficacy; on the other hand, the chlorpyrifos microcapsules prepared by using sodium alginate as the wall material have better dispersibility in the prepared microemulsion, and the spherical structure and surface characteristics of the microcapsules are also helpful to increase the uniformity and stability of the microemulsion, and prevent the precipitation and stratification of the chlorpyrifos microemulsion.

[0012] The composite preparation of microcapsule wall materials with cellulose filler and sodium alginate can improve the structure of the microcapsule wall, form a porous or mesh structure, enhance the barrier function of the wall material to the active ingredient of chlorpyrifos in the core material, and further reduce the volatilization and degradation of the active ingredient of chlorpyrifos. Cellulose has good mechanical strength and thermal stability, which can further improve the mechanical properties and stability of chlorpyrifos microcapsules at high temperatures, reduce heat-induced denaturation or damage, and improve stability during processing and application.

[0013] Prepare CaCl2 solution as receiving liquid for solidification, Ca 2+ It can quickly form ionic crosslinks with the carboxyl groups in the sodium alginate molecules to form a stable gel network structure, accelerate solidification, and further enhance the stability of the chlorpyrifos microcapsule wall, so that it can maintain good structural integrity and chemical stability under different environmental conditions.

[0014] Optionally, the mass ratio of the chlorpyrifos to the epoxy fatty acid methyl ester is 1:(0.5-1.5).

[0015] By adopting the above technical solution, epoxy fatty acid methyl ester is a compound derived from natural plant oil. As a core material solvent, it helps to promote the dissolution of chlorpyrifos and obtain a more stable and uniform core material solution. The appropriate mass ratio helps to improve the encapsulation rate of chlorpyrifos and ensure the stability and release control of the active ingredients in the microcapsules.

[0016] Optionally, the cellulose filler is carboxymethyl cellulose.

[0017] By adopting the above technical scheme, carboxymethyl cellulose as a cellulose filler has good hydrophilicity, can increase the hydrophilicity of the wall material of the chlorpyrifos microcapsule, help form a stable dispersion system in the aqueous phase, prevent microcapsules from aggregating, ensure their uniform and stable distribution in the microemulsion, and prevent the precipitation and stratification of the chlorpyrifos microemulsion; can adjust the pore structure of the microcapsule wall, regulate the release rate of the chlorpyrifos active ingredient in the core material, so that the drug effect has a lasting effect; and can improve the dispersibility of the microcapsules in the aqueous medium.

[0018] Optionally, the flow rate of the core material solution is 50-100 mL / h, and the flow rate of the wall material solution is 200-400 mL / h.

[0019] By adopting the above technical solution, the fluid dynamics during the formation of chlorpyrifos microcapsules can be accurately controlled by controlling the flow rate, thereby obtaining a uniform microcapsule structure and improving the preparation efficiency and quality.

[0020] Optionally, the nonionic surfactant is selected from any one of Nongru 600 or OP-10.

[0021] Optionally, the anionic surfactant is selected from any one of sodium dodecylbenzene sulfonate, sodium dibutylnaphthalene sulfonate, and sodium lauryl polyether sulfate.

[0022] Optionally, the stabilizer is selected from any one or more of ethanol, isopropanol, butanol, ethylene glycol and octanol.

[0023] By adopting the above technical solution and adding an appropriate amount of stabilizer, phase separation and precipitation of the microemulsion during storage and use can be prevented. Compared with other types of stabilizers, alcohol substances are safer and more biodegradable.

[0024] In a second aspect, the present application provides a method for preparing a chlorpyrifos microemulsion, using the following technical solution: A method for preparing a chlorpyrifos microemulsion comprises the following steps: The water in the raw material is divided into water A and water B with a mass ratio of 1:(2-4), and the chlorpyrifos microcapsules, the nonionic surfactant and the water A are mixed and stirred until dissolved to obtain an oil phase; Mix anionic surfactant, stabilizer and water B and stir until dissolved to obtain a water phase; Add the oil phase dropwise into the water phase, stir at a speed of 1500-2500 r / min for 20-40 min, and shear for 3-5 min to obtain the product.

[0025] By adopting the above technical solution, mixing and stirring in steps, the preparation process is simple and easy to scale up. High-speed stirring and shear mixing are helpful to form a uniform microemulsion system and improve the stability and use effect of the product.

[0026] In summary, this application has the following beneficial effects: 1. The present application uses sodium alginate and cellulose fillers as wall materials and chlorpyrifos as core material to prepare microcapsules, which significantly improves the hydrophilicity and biocompatibility of chlorpyrifos microcapsules, promotes the formation of a stable dispersion system of chlorpyrifos microcapsules in aqueous media, prevents mutual aggregation and sedimentation between microcapsules, and significantly improves the chemical stability of chlorpyrifos microemulsion.

[0027] 2. The chlorpyrifos is microencapsulated, and the wall material forms a wrapping network outside the chlorpyrifos, which can effectively reduce the volatilization loss of the active ingredient of chlorpyrifos, improve the adaptability of the chlorpyrifos microemulsion to environmental temperature and humidity, avoid the reduction of efficacy due to external influences such as thermal decomposition during storage and transportation, and control the sustained release of chlorpyrifos to improve the durability of the efficacy of the chlorpyrifos microemulsion during use.

[0028] 3. The present application uses a nonionic surfactant and an anionic surfactant to form a composite surfactant system, which has a better emulsification effect than two simple surfactants, so that the chlorpyrifos microemulsion forms a stable emulsification system, improves chemical stability, and helps to reduce stratification and precipitation problems. DETAILED DESCRIPTION

[0029] The following examples further illustrate the present application in detail.

[0030] raw material Unless otherwise specified, the raw materials used in the preparation examples, embodiments and comparative examples in this application are all commercially available products, specifically: Chlorpyrifos, selected from Guangzhou Zhuokang Pharmaceutical Co., Ltd., CAS2921-88-2; Sodium alginate, selected from Henan Haoxuan Chemical Products Co., Ltd., 1-556; Carboxymethyl cellulose, selected from Hebei Yufei Chemical Co., Ltd., 0019; Epoxy fatty acid methyl ester, selected from Shandong Haoyao New Materials Co., Ltd., HY4655; Polylactic acid, selected from Dongguan Chenxu Plastic Co., Ltd., PLA FY804; Nongru 600, selected from Haian Petrochemical Plant, Jiangsu Province, 600#; OP-10, selected from Haian Petrochemical Plant, Jiangsu Province, OP-10; Sodium dodecylbenzene sulfonate, selected from Guangdong Zhongrun Chemical Co., Ltd., K12; Sodium dibutylnaphthalene sulfonate, selected from Guangzhou Baishun Chemical Technology Co., Ltd., BS-121; Sodium laureth sulfate, selected from Shanghai Ruidong Chemical Group Co., Ltd., 546743.

[0031] Preparation Example of Chlorpyrifos Microcapsules Preparation Example 1 The chlorpyrifos microcapsules have a structure in which a core material is wrapped by a wall material, wherein the cellulose filler is carboxymethyl cellulose. The preparation method of the chlorpyrifos microcapsules comprises the following steps: S1: mixing chlorpyrifos and epoxy fatty acid methyl ester in a mass ratio of 1:1, and ultrasonically treating for 20 minutes to obtain a core material solution; S2: Sodium alginate and cellulose filler are mixed evenly in a mass ratio of 10:3, mixed with water in a solid-liquid ratio of 1:8, and ultrasonically treated for 20 minutes to obtain a wall material solution; S3: Prepare 6% CaCl2 solution as receiving liquid, and pass the core material solution at a flow rate of 100mL / h and the wall material solution at a flow rate of 300mL / h into the microfluidic chip respectively. Use the airflow as the driving phase through microfluidic technology and utilize the shearing effect of the airflow to form microdroplets in the chip. Then collect them in the CaCl2 solution and solidify for 40 minutes, and obtain them after centrifugation.

[0032] Preparation Example 2 The chlorpyrifos microcapsules have a structure in which a core material is wrapped by a wall material, wherein the cellulose filler is carboxymethyl cellulose. The preparation method of the chlorpyrifos microcapsules comprises the following steps: S1: chlorpyrifos and epoxy fatty acid methyl ester were mixed in a mass ratio of 1:0.5, and ultrasonic treatment was performed for 20 minutes to obtain a core material solution; S2: sodium alginate and cellulose filler were mixed in a mass ratio of 7:2.5, mixed with water in a solid-liquid ratio of 1:7, and ultrasonic treatment was performed for 20 minutes to obtain a wall material solution; S3: Prepare 5% CaCl2 solution as receiving liquid, and pass the core material solution at a flow rate of 50mL / h and the wall material solution at a flow rate of 200mL / h into the microfluidic chip respectively. Use the airflow as the driving phase through microfluidic technology and utilize the shearing effect of the airflow to form microdroplets in the chip. Then collect them in the CaCl2 solution and solidify for 40 minutes, and obtain them after centrifugation.

[0033] Preparation Example 3 The chlorpyrifos microcapsules have a structure in which a core material is wrapped by a wall material, wherein the cellulose filler is carboxymethyl cellulose. The preparation method of the chlorpyrifos microcapsules comprises the following steps: S1: chlorpyrifos and epoxy fatty acid methyl ester were mixed in a mass ratio of 1:1.5, and ultrasonic treatment was performed for 20 minutes to obtain a core material solution; S2: sodium alginate and cellulose filler were mixed in a mass ratio of 16:4.5, mixed with water in a solid-liquid ratio of 1:10, and ultrasonic treatment was performed for 20 minutes to obtain a wall material solution; S3: Prepare 7% CaCl2 solution as receiving liquid, and pass the core material solution at a flow rate of 100mL / h and the wall material solution at a flow rate of 200mL / h into the microfluidic chip respectively. Use the airflow as the driving phase through microfluidic technology and utilize the shearing effect of the airflow to form microdroplets in the chip. Then collect them in the CaCl2 solution and solidify for 40 minutes, and obtain them after centrifugation.

[0034] Preparation Example 4 The chlorpyrifos microcapsules have a structure in which a core material is wrapped by a wall material, wherein the cellulose filler is carboxymethyl cellulose. The preparation method of the chlorpyrifos microcapsules comprises the following steps: S1: chlorpyrifos and epoxy fatty acid methyl ester were mixed in a mass ratio of 1:1.2, and ultrasonic treatment was performed for 20 minutes to obtain a core material solution; S2: sodium alginate and cellulose filler were mixed in a mass ratio of 13:3.5, mixed with water in a solid-liquid ratio of 1:9, and ultrasonic treatment was performed for 20 minutes to obtain a wall material solution; S3: Prepare 8% CaCl2 solution as receiving liquid, and pass the core material solution at a flow rate of 70mL / h and the wall material solution at a flow rate of 400mL / h into the microfluidic chip respectively. Use the airflow as the driving phase through microfluidic technology and utilize the shearing effect of the airflow to form microdroplets in the chip. Then collect them in the CaCl2 solution and solidify for 40 minutes, and obtain them after centrifugation.

[0035] Preparation Example 5 The difference between the chlorpyrifos microcapsules and Preparation Example 1 is that no cellulose filler is added when preparing the wall material solution, the cellulose filler in the raw material is replaced by an equal mass of sodium alginate, and the other steps are the same as Preparation Example 1.

[0036] Preparation Example 6 The difference between the chlorpyrifos microcapsules and Preparation Example 1 is that no sodium alginate is added when preparing the wall material solution, and the sodium alginate in the raw material is replaced by polylactic acid of equal mass, and the other steps are the same as Preparation Example 1. Example

[0037] Example 1 A chlorpyrifos microemulsion, wherein the raw materials and the amounts of the raw materials are shown in Table 1, wherein the chlorpyrifos microcapsules are obtained from Preparation Example 1, the nonionic surfactant is Nongru 600, the anionic surfactant is sodium dodecylbenzene sulfonate, and the stabilizer is ethylene glycol.

[0038] Table 1 Components Example 1 Example 2 Example 3 Example 4 Chlorpyrifos microcapsules / % 40 30 20 50 Nonionic surfactant / % 10 15 8 12 Anionic surfactant / % 12 18 15 18 Stabilizer / % 2 1 1.5 3 water / % Up to 100 Up to 100 Up to 100 Up to 100 The preparation method of the chlorpyrifos microemulsion comprises the following steps: S1: Divide the water in the raw material into water A and water B with a mass ratio of 1:3, mix and stir the chlorpyrifos microcapsules, nonionic surfactant and water A until dissolved, to obtain an oil phase; S2: Mixing anionic surfactant, stabilizer and water B and stirring until dissolved to obtain an aqueous phase; S3: Add the oil phase dropwise into the water phase, stir at a speed of 2000 r / min for 40 min, and shear for 5 min to obtain.

[0039] Example 2 A chlorpyrifos microemulsion, which is different from Example 1 in that the raw materials and the amounts of the raw materials are as shown in Table 1, wherein the nonionic surfactant is OP-10, the anionic surfactant is sodium dibutylnaphthalene sulfonate, and the stabilizer is octanol.

[0040] The preparation method of the chlorpyrifos microemulsion comprises the following steps: S1: Divide the water in the raw material into water A and water B with a mass ratio of 1:2, mix and stir the chlorpyrifos microcapsules, nonionic surfactant and water A until dissolved, and obtain an oil phase; S2: Mixing anionic surfactant, stabilizer and water B and stirring until dissolved to obtain an aqueous phase; S3: Add the oil phase dropwise into the water phase, stir at a speed of 1500 r / min for 30 min, and shear for 3 min to obtain.

[0041] Example 3 A chlorpyrifos microemulsion, which is different from Example 1 in that the raw materials and the amounts of the raw materials are as shown in Table 1, wherein the nonionic surfactant is Nongru 600, the anionic surfactant is sodium lauryl polyether sulfate, and the stabilizer is butanol.

[0042] The preparation method of the chlorpyrifos microemulsion comprises the following steps: S1: Divide the water in the raw material into water A and water B with a mass ratio of 1:4, mix and stir the chlorpyrifos microcapsules, nonionic surfactant and water A until dissolved to obtain an oil phase; S2: Mixing anionic surfactant, stabilizer and water B and stirring until dissolved to obtain an aqueous phase; S3: Add the oil phase dropwise into the water phase, stir at a speed of 2500 r / min for 20 min, and shear for 5 min to obtain.

[0043] Example 4 A chlorpyrifos microemulsion, which is different from Example 1 in that the raw materials and the amounts of the raw materials are as shown in Table 1, and the other steps are the same as those in Example 1.

[0044] Example 5 A chlorpyrifos microemulsion is different from Example 1 in that the chlorpyrifos microcapsules in the raw material are obtained from Preparation Example 2, and the other steps are the same as those in Example 1.

[0045] Example 6 A chlorpyrifos microemulsion is different from Example 1 in that the chlorpyrifos microcapsules in the raw material are obtained from Preparation Example 3, and the other steps are the same as those in Example 1.

[0046] Example 7 A chlorpyrifos microemulsion is different from Example 1 in that the chlorpyrifos microcapsules in the raw material are obtained from Preparation Example 4, and the other steps are the same as those in Example 1.

[0047] Comparative Example Comparative Example 1 A chlorpyrifos microemulsion is different from Example 1 in that the chlorpyrifos microcapsules in the raw material are obtained from Preparation Example 5, and the other steps are the same as those in Example 1.

[0048] Comparative Example 2 A chlorpyrifos microemulsion is different from Example 1 in that the chlorpyrifos microcapsules in the raw material are obtained from Preparation Example 6, and the other steps are the same as those in Example 1.

[0049] Comparative Example 3 A chlorpyrifos microemulsion, which is different from Example 1 in that the chlorpyrifos is not microencapsulated, the chlorpyrifos microcapsules in the raw materials are replaced with chlorpyrifos of equal mass, and the other steps are the same as those in Example 1.

[0050] Comparative Example 4 A chlorpyrifos microemulsion, which differs from Example 1 in that no anionic surfactant is used, the anionic surfactant in the raw material is replaced by a nonionic surfactant of equal mass, and the other steps are the same as those in Example 1.

[0051] Performance testing Test Example 1: Stability Test The stability of Examples 1-7 and Comparative Examples 1-4 was tested, and the experimental results are recorded in Table 2.

[0052] 1. Thermal stability: According to the provisions of GB / T19136-2003 Determination of thermal storage stability of pesticides, place it at 54±2℃ for 14 days and calculate the thermal storage decomposition rate after storage; 2. Low temperature stability: According to the provisions of GB / T19137-2003 Determination of low temperature stability of pesticides, place it in a refrigerator at 0±1℃ for 7 days and calculate the cold storage decomposition rate after storage; 3. Room temperature stability: According to the provisions of "NY / T 1427-2016 General Rules for Storage Stability Test of Pesticides at Room Temperature", store at room temperature for 14 days and calculate the storage decomposition rate after storage; 4. Emulsion stability: The test was conducted in accordance with GB / T1603-2001 Test Method for Stability of Pesticide Emulsions. The sample was diluted 20 times in standard hard water, inverted 30 times, and placed in a constant temperature water bath at 30±1℃ for 1 hour. The microemulsion was taken out and observed for 1 hour. If there was no floating oil on the top and no precipitation on the bottom, and no concentration gradient visible to the naked eye in the middle, the emulsion stability of the chlorpyrifos microemulsion was qualified.

[0053] Table 2 It can be seen from the performance test results in Table 2 that the chlorpyrifos microemulsion of the present application has good chemical stability, can adapt to different temperature conditions, maintain a good microemulsion state, and effectively reduce the occurrence of microemulsion stratification and precipitation.

[0054] According to the performance test results of Examples 1-7 and Comparative Examples 1-3, it can be seen that preparing a microemulsion after microencapsulation of chlorpyrifos can effectively improve the chemical stability of the chlorpyrifos microemulsion, improve the adaptability of the chlorpyrifos microcapsules to different ambient temperatures, and help reduce the problems of stratification and precipitation.

[0055] Compared with other wall materials, sodium alginate as a wall material has stronger mutual adaptability with the core material chlorpyrifos, forming a wrapping network outside the chlorpyrifos, promoting the compatibility between chlorpyrifos and the aqueous medium, and improving the chemical stability of the chlorpyrifos microemulsion. The addition of nano-element fillers and the combination with sodium alginate further strengthen the protective effect of the core material chlorpyrifos, and further promote the compatibility and stability of chlorpyrifos in the aqueous phase.

[0056] It can be seen from the performance test results of Examples 1-7 and Comparative Example 4 that the composite surfactant system formed by mixing nonionic and anionic surfactants has a better emulsification effect on the chlorpyrifos microemulsion than a single surfactant, which helps to promote the chlorpyrifos microemulsion to maintain good stability under different environments and prevent stratification and precipitation.

[0057] Test Example 2 Field Control Test A chlorpyrifos microemulsion obtained in Examples 1-7 was used as the experimental group, and a commercially available chlorpyrifos emulsifiable concentrate (selected from Shandong Huayang Pesticide Chemical Group Co., Ltd.) was used as the control group. Referring to the provisions of "GB / T 17980.13-2000 Pesticide Field Efficacy Test Guidelines (I) Insecticides for Control of Lepidoptera Larvae of Vegetables", the agent was diluted with water at a ratio of 1:100 and sprayed in a constant volume to conduct a field test on the control of diamondback moth. The experimental site was a farmland in Jiaozhou, Qingdao City, Shandong Province, and the experimental results are recorded in Table 3.

[0058] Table 3 According to the field test results in Table 3, it can be seen that the chlorpyrifos microemulsion of the present application can continuously release the active ingredient, the drug effect is more lasting, and compared with the existing similar pesticides, it has a more excellent control effect, can replace the currently widely used chlorpyrifos emulsifiable concentrate, reduce the pollution of the drug solution to the environment, and save the control cost.

[0059] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A chlorpyrifos microemulsion, characterized in that: In terms of mass percentage, the raw materials include 20-50% of chlorpyrifos microcapsules, 8-15% of nonionic surfactants, 12-18% of anionic surfactants, 1-3% of stabilizers, and the balance is water; The chlorpyrifos microcapsule has a structure in which a core material is wrapped by a wall material, and the raw materials include chlorpyrifos, epoxy fatty acid methyl ester, sodium alginate, cellulose filler and CaCl2.

2. The chlorpyrifos microemulsion according to claim 1, characterized in that The preparation method of the chlorpyrifos microcapsules comprises the following steps: Chlorpyrifos and epoxy fatty acid methyl ester are mixed, and a core material solution is obtained after ultrasonic treatment; sodium alginate and cellulose filler are mixed evenly in a mass ratio of (7-16):(2.5-4.5), and mixed with water in a material-liquid ratio of 1:(7-10), and a wall material solution is obtained after ultrasonic treatment; Prepare 5-8% CaCl2 solution as receiving liquid, pass the core material solution and the wall material solution into the microfluidic chip respectively, form microdroplets in the chip through microfluidic technology, and then collect them in CaCl2 solution to solidify, and obtain them after centrifugation.

3. The chlorpyrifos microemulsion according to claim 2, characterized in that: The mass ratio of the chlorpyrifos to the epoxy fatty acid methyl ester is 1:(0.5-1.5).

4. The chlorpyrifos microemulsion according to claim 2, characterized in that: The cellulose filler is carboxymethyl cellulose.

5. The chlorpyrifos microemulsion according to claim 2, characterized in that: The flow rate of the core material solution is 50-100 mL / h, and the flow rate of the wall material solution is 200-400 mL / h.

6. The chlorpyrifos microemulsion according to claim 1, characterized in that: The nonionic surfactant is selected from any one of Nongru 600 and OP-10.

7. The chlorpyrifos microemulsion according to claim 1, characterized in that: The anionic surfactant is selected from any one of sodium dodecylbenzene sulfonate, sodium dibutylnaphthalene sulfonate and sodium lauryl alcohol polyether sulfate.

8. The chlorpyrifos microemulsion according to claim 1, characterized in that: The stabilizer is selected from any one or more of ethanol, isopropanol, butanol, ethylene glycol and octanol.

9. The method for preparing the chlorpyrifos microemulsion according to any one of claims 1 to 8, characterized in that: The following steps are involved: The water in the raw material is divided into water A and water B with a mass ratio of 1:(2-4), and the chlorpyrifos microcapsules, the nonionic surfactant and the water A are mixed and stirred until dissolved to obtain an oil phase; Mix anionic surfactant, stabilizer and water B and stir until dissolved to obtain a water phase; Add the oil phase dropwise into the water phase, stir at a speed of 1500-2500 r / min for 20-40 min, and shear for 3-5 min to obtain the product.

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