A kind of pesticide microcapsule suspension and preparation method thereof

Abstract

The invention discloses a pesticide microcapsule suspension and a preparation method thereof, which belongs to the technical field of pesticide production, and comprises the following steps: weighing the pesticide original drug, stirring and adding an organic solvent thereto, adding modified isophorone diisocyanate thereto after ultrasonic stirring is completed, stirring and mixing to form an oil phase; weighing an emulsifier and a dispersant and mixing them, adding deionized water thereto, stirring and mixing at room temperature to form an aqueous phase; spraying the oil phase into the aqueous phase by a spray gun, and then shearing and emulsifying to form an oil-in-water emulsion, and then dripping a chain extender into the oil-in-water emulsion, and stirring, after the dripping is completed, continuing to stir at a uniform speed, and after the stirring is completed, the pesticide microcapsule suspension is obtained. Relative to the prior art, the pesticide microcapsule suspension prepared by the present invention has an improved encapsulation rate of the pesticide original drug, and is more in line with the development concept of environmental protection and green.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide production, and specifically relates to a pesticide microcapsule suspension and a preparation method thereof. Background Art

[0002] Pesticides, as important agricultural chemicals, are widely used to prevent and control pests and diseases, regulate plant growth, and increase crop yields. They are an important material basis for ensuring my country's food security. However, due to the use method and climatic conditions, only a small amount of pesticides are deposited on the surface of plant leaves, the effective utilization rate is generally less than 40%, and only 0.1% of the pesticides can act on the main targets. At present, the commonly used pesticide formulations in my country are mainly emulsifiable concentrates (EC) and wettable powders (WP). These traditional pesticide formulations have problems such as high organic solvent content, poor water dispersibility, dust drift, serious environmental pollution and low utilization rate. Therefore, it is imperative to develop new, efficient and environmentally friendly water-based pesticide formulations.

[0003] Microencapsulation of pesticides is a feasible method to overcome the shortcomings of traditional dosage forms. Microcapsules have the advantages of strong targeting, long lasting effect, controlled release, protection of the core material from environmental influences, reduced pesticide damage to non-target organisms and increased pesticide utilization. Microcapsules have gradually become a research hotspot for pesticide dosage forms.

[0004] Compared with microcapsules, microcapsule suspensions are new dosage forms. Microcapsule suspensions are active ingredients dispersed in water in the form of microcapsules and solid particles to form a stable suspension liquid preparation. Microcapsules have the disadvantage of poor rapid effect in the initial stage of release. The new microcapsule suspension can make up for the shortcomings of the microcapsule dosage form, give full play to the advantages of the microcapsule dosage form and suspension, and expand the scope of use of microcapsules and suspensions alone, so that the microcapsule suspension has both rapid effect and long-lasting effect.

[0005] A Chinese patent with authorization announcement number CN113040160B discloses a pesticide microcapsule suspension and a preparation method thereof. The pesticide microcapsule suspension disclosed in the patent includes the following raw materials: polyisocyanate prepolymer, pesticide technical, organic solvent, emulsifier, deionized water, chain extender and curing agent. The preparation method of the polyisocyanate prepolymer of the main wall material of the microcapsule includes: mixing polyether polyol, polyisocyanate and dibutyltin dilaurate, and performing polymerization reaction to obtain the polyisocyanate prepolymer, wherein the polyisocyanate includes one or two of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, tetramethylxylene diisocyanate and lysine diisocyanate. The traditional aromatic isocyanates (such as toluene diisocyanate and diphenylmethane diisocyanate) in the polyisocyanate used in the invention have better activity than aliphatic isocyanates (such as isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, tetramethylxylylene diisocyanate and tetramethylxylylene diisocyanate), and the reaction rate is faster. The microcapsule suspension prepared by using aromatic isocyanates has a better encapsulation rate. However, traditional aromatic isocyanates have certain toxicity and carcinogenicity, and the selection of polyisocyanates affects the development of pesticide microcapsule suspensions. Summary of the invention

[0006] The purpose of the present invention is to provide a pesticide microcapsule suspension and a preparation method thereof, and to at least achieve the purpose of increasing the encapsulation rate of the microcapsule suspension for the pesticide original drug and the environmentally friendly green development of the microcapsule suspension by improving the raw material composition and preparation method of the pesticide microcapsule suspension.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0009] S1. Weigh the pesticide technical, add the organic solvent thereto with stirring, perform ultrasonic stirring at a power of 40-100w for 10-50min, and after the ultrasonic stirring is completed, add the modified isophorone diisocyanate thereto, place at 60-70°C and stir and mix for 30-50min to form an oil phase;

[0010] S2, weighing an emulsifier and a dispersant, mixing them, adding deionized water thereto, stirring and mixing at room temperature of 25° C. for 30-50 minutes to form an aqueous phase;

[0011] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 3-5 min at a high shearing condition of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion and stirring. After the dropping is completed, continue to stir at a uniform speed for 2-3 h. After the stirring is completed, the pesticide microcapsule suspension is obtained.

[0012] Furthermore, the modified isophorone diisocyanate is prepared by the following steps:

[0013] Isophorone diisocyanate is added to acrylic acid with stirring to obtain a mixed solution, and dibutyltin dilaurate and p-hydroxyanisole are then added to the mixed solution with stirring. The system is heated to 70-80° C. and stirred at a constant temperature for 4-6 hours. After the reaction is completed, the system is cooled to room temperature, and then acid-washed, water-washed, and dried to obtain modified isophorone diisocyanate.

[0014] Further, the usage ratio of acrylic acid and isophorone diisocyanate is 1L:0.5-0.55L;

[0015] The amount of dibutyltin dilaurate is 1.5-2.0wt%;

[0016] The dosage of the p-hydroxyanisole is 0.1-0.2 wt %.

[0017] Furthermore, the usage ratio of the pesticide technical, the organic solvent and the modified isophorone diisocyanate is 5-15g:50-100mL:8-25g.

[0018] Furthermore, the usage ratio of the emulsifier, dispersant and deionized water is 1.0-3.2 g: 0.5-2.0 g: 50-100 mL.

[0019] Furthermore, the volume ratio of the oil-in-water emulsion to the chain extender is 100:1-2.

[0020] Furthermore, the pesticide technical is one of a fungicide, a herbicide and an insecticide;

[0021] The fungicide is one of thiophanate-methyl technical and carbendazim technical;

[0022] The herbicide is one of hexazinone technical and isoproturon technical;

[0023] The insecticide is one of chlorpyrifos technical drug and thiamethoxam technical drug.

[0024] Furthermore, the organic solvent is one of xylene, n-butanol and n-octanol.

[0025] Furthermore, the emulsifier is a mixture of sodium lauryl sulfate and emulsifier EL-80 in a volume ratio of 3-5:1-2.

[0026] Furthermore, the dispersant is sodium alginate.

[0027] Furthermore, the chain extender is 1,4-butanediol.

[0028] Furthermore, a pesticide microcapsule suspension is prepared by the above preparation method.

[0029] Beneficial effects of the present invention:

[0030] The invention provides a pesticide microcapsule suspension and a preparation method thereof. Compared with the prior art, the pesticide microcapsule suspension prepared by the invention has an improved encapsulation rate of the original pesticide. Meanwhile, the invention improves the polyisocyanate of the main wall material of the microcapsule. The invention uses hydroxyethyl acrylate and isophorone diisocyanate to prepare modified isophorone diisocyanate through condensation reaction. Through the modification treatment of hydroxyethyl acrylate, the heat resistance during microcapsule formation can be improved, and the emulsion is prevented from breaking due to excessively high temperature during the interfacial polymerization process, thereby causing the stability and encapsulation rate of the pesticide microcapsules to decrease. After testing, the pesticide microcapsule suspension is prepared by using the modified isophorone diisocyanate prepared by the invention, and the pesticide microcapsule suspension finally prepared has an excellent encapsulation rate. Meanwhile, since the invention does not use the traditional aromatic isocyanate with toxicity and carcinogenicity, the microcapsule suspension prepared by the invention is more in line with the development concept of environmental protection and greenness compared with the prior art.

[0031] At the same time, the present invention adopts an interfacial polymerization method to prepare a polyurethane microcapsule suspension. The interfacial polymerization method utilizes an emulsifier to reduce the interfacial tension of each component in an oil-water mixture system. After emulsification, the dispersed phase is dispersed in the continuous phase in the form of micron-sized droplets to form a stable water-in-oil emulsion. The present invention achieves the purpose of regulating the particle size of microcapsules in the polyurethane microcapsule suspension by adjusting the caliber of the atomizing spray gun. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] Preparation of modified isophorone diisocyanate:

[0035] 0.5 L of isophorone diisocyanate was added to 1 L of acrylic acid with stirring to obtain a mixed solution, and then 1.5 wt % of dibutyltin dilaurate as a catalyst and 0.1 wt % of p-hydroxyanisole as an inhibitor were added to the mixed solution with stirring. The system was heated to 70 ° C and stirred at a constant temperature for 4 hours. After the reaction was completed, it was cooled to room temperature, and then acid-washed, water-washed, and dried to obtain modified isophorone diisocyanate.

[0036] Example 2

[0037] Preparation of modified isophorone diisocyanate:

[0038] 0.55 L of isophorone diisocyanate was added to 1 L of acrylic acid with stirring to obtain a mixed solution, and then 2.0 wt % of dibutyltin dilaurate as a catalyst and 0.2 wt % of p-hydroxyanisole as an inhibitor were added to the mixed solution with stirring. The system was heated to 80 ° C and stirred at a constant temperature for 6 hours. After the reaction was completed, it was cooled to room temperature, and then acid-washed, washed with water, and dried to obtain modified isophorone diisocyanate.

[0039] Example 3

[0040] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0041] S1. Weigh 5 g of the pesticide technical and place it in reactor A, then stir and add 50 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 40 W for 10 min, after the ultrasonic stirring is completed, add 8 g of the modified isophorone diisocyanate prepared in Example 1 to reactor A, place it at 60 ° C and stir and mix for 30 min to form an oil phase, wherein the pesticide technical is a fungicide, and the fungicide is methyl thiophanate technical (CAS: 23564-05-8; homemade); wherein the organic solvent is xylene.

[0042] S2. Weigh 1.0 g of an emulsifier and 0.5 g of a dispersant, and place them in a reactor B. Add 50 mL of deionized water to the reactor B, and stir and mix for 30 min at room temperature of 25 ° C to form an aqueous phase, wherein the emulsifier is sodium dodecyl sulfate (SDS) and emulsifier EL-80 mixed in a volume ratio of 3:1; wherein the dispersant is sodium alginate (SA).

[0043] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 3 minutes under high-speed shear conditions of 10,000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:1, and stirring at a speed of 400 r / min at the same time. After the dropwise addition is completed, stirring is continued at a uniform speed for 2 hours. After the stirring is completed, the pesticide microcapsule suspension is obtained after centrifugation, washing, and drying, wherein the chain extender is 1,4-butanediol (BDO).

[0044] Example 4

[0045] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0046] S1. Weigh 8 g of the pesticide technical and place it in reactor A, then stir and add 60 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 55 W for 20 min, and after the ultrasonic stirring is completed, add 10 g of the modified isophorone diisocyanate prepared in Example 1 to reactor A, stir and mix at 65 ° C for 35 min to form an oil phase, wherein the pesticide technical is a fungicide; the fungicide is carbendazim technical (CAS: 10605-21-7; white powder; homemade); wherein the organic solvent is n-butanol.

[0047] S2. Weigh 1.5 g of an emulsifier and 0.8 g of a dispersant, and place them in a reactor B. Add 60 mL of deionized water to the reactor B, and stir and mix for 35 min at room temperature of 25 ° C to form an aqueous phase, wherein the emulsifier is sodium dodecyl sulfate (SDS) and emulsifier EL-80 mixed in a volume ratio of 3:2; wherein the dispersant is sodium alginate (SA).

[0048] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 3 minutes under high-speed shear conditions of 10,000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:1.5, and stirring at a speed of 450 r / min at the same time. After the dropwise addition is completed, continue to stir at a uniform speed for 2 hours. After the stirring is completed, centrifuge, wash, and dry to obtain the pesticide microcapsule suspension, wherein the chain extender is 1,4-butanediol (BDO).

[0049] Example 5

[0050] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0051] S1. Weigh 10 g of the pesticide technical and place it in reactor A, then stir and add 80 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 80 W for 30 min, and after the ultrasonic stirring is completed, add 15 g of the modified isophorone diisocyanate prepared in Example 2 to reactor A, stir and mix at 70 ° C for 40 min to form an oil phase, wherein the pesticide technical is a herbicide; the herbicide is hexazinone technical (CAS: 51235-04-2; homemade); wherein the organic solvent is n-octanol.

[0052] S2. Weigh 2.0 g of an emulsifier and 1.0 g of a dispersant, and place them in a reactor B. Add 80 mL of deionized water to the reactor B, and stir and mix for 40 min at room temperature of 25 ° C to form an aqueous phase, wherein the emulsifier is sodium dodecyl sulfate (SDS) and emulsifier EL-80 mixed in a volume ratio of 4:1; wherein the dispersant is sodium alginate (SA).

[0053] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 5 minutes under high-speed shear conditions of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:2, and stirring at a speed of 500 r / min at the same time. After the dropwise addition is completed, stirring is continued at a uniform speed for 3 hours. After the stirring is completed, the pesticide microcapsule suspension is obtained after centrifugation, washing, and drying, wherein the chain extender is 1,4-butanediol (BDO).

[0054] Example 6

[0055] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0056] S1. Weigh 12 g of the pesticide technical and place it in reactor A, then stir and add 80 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 80 w for 40 min, after the ultrasonic stirring is completed, add 18 g of the modified isophorone diisocyanate prepared in Example 2 to reactor A, place it under stirring and mixing conditions of 70 ° C for 40 min to form an oil phase, wherein the pesticide technical is a herbicide; the herbicide is isoproturon technical (CAS: 34123-59-6; homemade); wherein the organic solvent is xylene.

[0057] S2. Weigh 2.5 g of emulsifier and 1.4 g of dispersant, and place them in reactor B. Add 800 mL of deionized water to reactor B, and stir and mix for 40 min at room temperature of 25 ° C to form an aqueous phase, wherein the emulsifier is sodium dodecyl sulfate (SDS) and emulsifier EL-80 mixed in a volume ratio of 2: 1; wherein the dispersant is sodium alginate (SA).

[0058] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 5 minutes under high-speed shear conditions of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:2, and stirring at a speed of 500 r / min at the same time. After the dropwise addition is completed, stirring is continued at a uniform speed for 3 hours. After the stirring is completed, the pesticide microcapsule suspension is obtained after centrifugation, washing, and drying, wherein the chain extender is 1,4-butanediol (BDO).

[0059] Example 7

[0060] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0061] S1. Weigh 15 g of the pesticide technical and place it in reactor A, then stir and add 100 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 100 w for 50 min, and after the ultrasonic stirring is completed, add 25 g of the modified isophorone diisocyanate prepared in Example 2 to reactor A, stir and mix at 70 ° C for 50 min to form an oil phase, wherein the pesticide technical is an insecticide; the insecticide is chlorpyrifos technical (CAS: 2921-88-2; white granular crystals; homemade); wherein the organic solvent is n-butanol.

[0062] S2. Weigh 3.2 g of an emulsifier and 2.0 g of a dispersant, and place them in a reactor B. Add 100 mL of deionized water to the reactor B, and stir and mix for 50 min at room temperature of 25 ° C to form an aqueous phase, wherein the emulsifier is sodium dodecyl sulfate (SDS) and emulsifier EL-80 mixed in a volume ratio of 5:1; wherein the dispersant is sodium alginate (SA).

[0063] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 5 minutes under high-speed shear conditions of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:2, and stirring at a speed of 500 r / min at the same time. After the dropwise addition is completed, stirring is continued at a uniform speed for 3 hours. After the stirring is completed, the pesticide microcapsule suspension is obtained after centrifugation, washing, and drying, wherein the chain extender is 1,4-butanediol (BDO).

[0064] Example 8

[0065] A method for preparing a pesticide microcapsule suspension comprises the following steps:

[0066] S1. Weigh 15 g of the pesticide technical and place it in reactor A, then stir and add 100 mL of the organic solvent thereto, perform ultrasonic stirring at a power of 100 W for 50 min, and after the ultrasonic stirring is completed, add 25 g of the modified isophorone diisocyanate prepared in Example 2 to reactor A, stir and mix at 70 ° C for 50 min to form an oil phase, wherein the pesticide technical is an insecticide; the insecticide is thiamethoxam technical (CAS: 153719-23-4; white or light yellow powder; homemade); wherein the organic solvent is n-octanol.

[0067] S2. Weigh 3.2 g of an emulsifier and 2.0 g of a dispersant, and place them in a reactor B. Add 100 mL of deionized water to the reactor B, and stir and mix for 50 min at room temperature of 25° C. to form an aqueous phase, wherein the emulsifier is emulsifier EL-80; and the dispersant is sodium alginate (SA).

[0068] S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then performing shear emulsification for 5 minutes under high-speed shear conditions of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion, the volume ratio of the oil-in-water emulsion to the chain extender is 100:2, and stirring at a speed of 500 r / min at the same time. After the dropwise addition is completed, stirring is continued at a uniform speed for 3 hours. After the stirring is completed, the pesticide microcapsule suspension is obtained after centrifugation, washing, and drying, wherein the chain extender is 1,4-butanediol (BDO).

[0069] Comparative Example 1

[0070] Comparative Example 1 is the control group of Example 5, in which 15 g of the modified isophorone diisocyanate prepared in Example 2 in step S1 of Example 5 is replaced with isophorone diisocyanate, and the other raw materials and the preparation process remain unchanged, and finally the pesticide microcapsule suspension is obtained.

[0071] The performance test of the pesticide microcapsule suspension prepared in Examples 3 to 8 and Comparative Example 1 was performed. The performance test process is as follows, and the test results are shown in Table 1:

[0072] Determination of encapsulation efficiency:

[0073] Weigh 0.01 of the pesticide microcapsule suspension prepared in Examples 3-8 and Comparative Example 1 respectively and disperse in 100 mL of xylene, shake and evenly oscillate for 1 min, and centrifuge to obtain the supernatant of the free active ingredient outside the capsule. The supernatant was then transferred to a 50L volumetric flask and fixed to volume with anhydrous methanol. At the same time, an appropriate amount of anhydrous methanol was added to the precipitate after centrifugation, and ultrasonically crushed to completely dissolve the pesticide original drug in the microcapsule in anhydrous methanol, and then fixed to volume with anhydrous methanol. The content of the pesticide original drug in the supernatant and the precipitate was determined using a high performance liquid chromatograph. The encapsulation efficiency calculation formula is as follows:

[0074] Encapsulation efficiency (%) = (1-content of free active ingredient outside the capsule / total amount of active ingredient) × 100%.

[0075] Table 1

[0076] project Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Encapsulation efficiency 93.17％ 93.22％ 93.28％ 93.26％ 93.11％ 93.02％ 86.17％

[0077] It can be seen from Table 1 that the pesticide microcapsule suspensions prepared in Examples 3-8 of the present invention have excellent encapsulation efficiency. At the same time, since the present invention does not use traditional toxic and carcinogenic aromatic isocyanates, compared with the prior art, the microcapsule suspensions prepared by the present invention are more in line with the concept of environmental protection and green development.

[0078] It should be noted that, in this article, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment.

[0079] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a pesticide microcapsule suspension, characterized in that: The following steps are involved: S1. Weigh the pesticide technical, add the organic solvent thereto with stirring, perform ultrasonic stirring at a power of 40-100w for 10-50min, and after the ultrasonic stirring is completed, add the modified isophorone diisocyanate thereto, place at 60-70°C and stir and mix for 30-50min to form an oil phase; S2, weighing an emulsifier and a dispersant, mixing them, adding deionized water thereto, stirring and mixing at room temperature of 25° C. for 30-50 minutes to form an aqueous phase; S3, spraying the oil phase into the water phase with a 0.1 mm aperture spray gun, and then shearing and emulsifying for 3-5 min under a high-speed shearing condition of 10000 rpm to form an oil-in-water emulsion, and then dropping a chain extender into the oil-in-water emulsion and stirring. After the dropwise addition is completed, continue to stir at a uniform speed for 2-3 h. After the stirring is completed, the pesticide microcapsule suspension is obtained; The modified isophorone diisocyanate is prepared by the following steps: Add isophorone diisocyanate to acrylic acid with stirring to obtain a mixed solution, then add dibutyltin dilaurate and p-hydroxyanisole to the mixed solution with stirring, heat the system to 70-80° C., stir and react at constant temperature for 4-6 hours, and after the reaction is completed, cool to room temperature, then acid-wash, wash with water, and dry to obtain modified isophorone diisocyanate; The usage ratio of acrylic acid and isophorone diisocyanate is 1L:0.5-0.55L; The amount of dibutyltin dilaurate is 1.5-2.0wt%; The dosage of the p-hydroxyanisole is 0.1-0.2 wt %.

2. The method for preparing a pesticide microcapsule suspension according to claim 1, characterized in that: The dosage ratio of the pesticide technical, the organic solvent and the modified isophorone diisocyanate is 5-15g:50-100mL:8-25g.

3. The method for preparing a pesticide microcapsule suspension according to claim 1, characterized in that: The usage ratio of the emulsifier, dispersant and deionized water is 1.0-3.2g:0.5-2.0g:50-100mL.

4. The method for preparing a pesticide microcapsule suspension according to claim 1, characterized in that: The volume ratio of the oil-in-water emulsion to the chain extender is 100:1-2.

5. The method for preparing a pesticide microcapsule suspension according to claim 1, characterized in that: The pesticide technical is one of a fungicide, a herbicide and an insecticide.

6. The method for preparing a pesticide microcapsule suspension according to claim 5, characterized in that: The fungicide is one of methyl thiophanate technical and carbendazim technical; the herbicide is one of hexazinone technical and isoproturon technical; the insecticide is one of chlorpyrifos technical and thiamethoxam technical.

7. The method for preparing a pesticide microcapsule suspension according to claim 1, characterized in that: The organic solvent is one of xylene, n-butanol and n-octanol; The emulsifier is a mixture of sodium lauryl sulfate and emulsifier EL-80 in a volume ratio of 3-5:1-2; The dispersant is sodium alginate; The chain extender is 1,4-butanediol.

8. A pesticide microcapsule suspension, characterized in that: Prepared by the preparation method described in any one of claims 1 to 7.