Pesticide microcapsule suspending agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of pesticide preparations, in particular to a pesticide microcapsule suspending agent and a preparation method and application thereof. According to the pesticide microcapsule suspending agent, microcapsules are prepared from the following raw materials in parts by mass: 2 to 7 parts of urea, 7 to 24.5 parts of formaldehyde, 3 to 9 parts of an emulsifier, 0.1 to 1 part of a de-foaming agent, 2 to 4 parts of a diluent, 10 to 15 parts of a synergistic auxiliary agent, 2 to 4 parts of a dispersing agent and 25 to 35 parts of 2, 4-dichlorphenoxyacetic acid, the synergistic auxiliary agent is prepared from the following raw materials in parts by mass: 0.5 to 1.5 parts of carboxymethyl porous Chinese chestnut starch, 0.5 to 1.5 parts of sodium alginate, 1.5 to 2.5 parts of calcium chloride, 2.5 to 3.5 parts of alginate, 1.5 to 2.5 parts of beta-cyclodextrin and 1 to 2 parts of a coupling agent; according to the pesticide microcapsule suspending agent prepared in the invention, the synergistic additive is added, so that 2, 4-dichlorophenoxyacetic acid can be effectively coated, and the encapsulation efficiency and the pesticide effect utilization rate of 2, 4-dichlorophenoxyacetic acid are remarkably improved; meanwhile, the prepared pesticide microcapsule suspending agent has good photolysis resistance, rain wash resistance and stability.

Description

Technical Field

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

[0002] 2,4-Dichlorophenoxyacetic acid (2,4-D), a highly effective and selective phenoxycarboxylic acid herbicide, interferes with the cell division and elongation of broadleaf weeds by mimicking plant growth hormones. It is widely used in wheat, corn, and other gramineous crops to control annual / perennial broadleaf weeds such as shepherd's purse, lambsquarters, and amaranth, offering broad-spectrum weed control and low cost. To improve the residual effect and reduce environmental toxicity of 2,4-dichlorophenoxyacetic acid, microencapsulated suspensions have become an important formulation direction: by encapsulating 2,4-dichlorophenoxyacetic acid in a polymeric capsule wall material, controlled release and reduced loss can be achieved. However, existing 2,4-D microencapsulated suspension technologies still have significant drawbacks that limit their application effectiveness. 1. Low encapsulation rate: In traditional processes, 2,4-D has high water solubility and easily penetrates the capsule wall to diffuse into the aqueous phase. In addition, the capsule wall material has insufficient affinity with 2,4-D, resulting in a generally low encapsulation rate. A large amount of active ingredients are free outside the capsule, which not only reduces the utilization rate but also easily causes early phytotoxicity or environmental residues. II. Insufficient resistance to photodegradation and rain washout: On the one hand, the active ingredient 2,4-D is easily degraded by ultraviolet light, which limits the blocking effect of the existing microcapsule wall on ultraviolet light, thus the existing microcapsules have insufficient resistance to photodegradation. On the other hand, improper control of microcapsule particle size and cross-linking density of the capsule wall leads to low pesticide residue retention after application and rain washout, resulting in a large loss of active ingredients and unstable herbicidal effect. Therefore, the existing microcapsules have weak resistance to rain washout.

[0003] 3. Low weed control efficiency: Low encapsulation rate leads to rapid initial release of active ingredients, which can easily stress crops in the early stages; poor resistance to photodegradation and rain erosion further exacerbates the decay of active ingredients, resulting in poor weed control during the effective period, requiring multiple applications, which increases costs and environmental burden.

[0004] Therefore, how to effectively solve the problems of poor encapsulation rate, poor resistance to photolysis, poor resistance to rain erosion, and low weeding efficiency of existing 2,4-D microcapsule suspensions has become an urgent issue to be addressed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides a pesticide microcapsule suspension, its preparation method, and its application.

[0006] In a first aspect, this application provides a pesticide microcapsule suspension, which adopts the following technical solution: A pesticide microcapsule suspension, wherein the microcapsules comprise the following raw materials in parts by weight: 2-7 parts urea, 7-24.5 parts formaldehyde, 3-9 parts emulsifier, 0.1-1 part defoamer, 2-4 parts diluent, 10-15 parts synergist, 2-4 parts dispersant, and 25-35 parts 2,4-dichlorophenoxyacetic acid; The synergistic additives include the following raw materials in parts by weight: 0.5-1.5 parts carboxymethyl porous chestnut starch, 0.5-1.5 parts sodium alginate, 1.5-2.5 parts calcium chloride, 2.5-3.5 parts alginate, 1.5-2.5 parts β-cyclodextrin, and 1-2 parts coupling agent.

[0007] By adopting the above technical solution, this application forms a calcium alginate-containing gel network with sodium alginate, carboxymethyl porous chestnut starch and calcium chloride. Under the action of a coupling agent, it is mixed with alginate ester and β-cyclodextrin to prepare a synergistic agent. Through the synergistic mechanism between the synergistic agent and each raw material, the encapsulation rate, anti-photolysis performance, anti-rain erosion performance and drug utilization rate of the microcapsule suspension are effectively improved. At the same time, the prepared microcapsule suspension has good stability.

[0008] Preferably, the coupling agent is coupling agent KH-550.

[0009] Preferably, the alginate is hexadecyl alginate with a degree of esterification of 15-18%; Preferably, the preparation method of the synergistic agent includes the following steps: Sodium alginate and water were mixed to obtain a sodium alginate aqueous solution with a mass fraction of 5%. Carboxymethyl porous chestnut starch and sodium alginate aqueous solution were mixed, and calcium chloride was added and mixed to obtain a mixture. Alginate and β-cyclodextrin are mixed, and then the mixture and coupling agent are added to obtain a synergistic agent.

[0010] By adopting the above technical solution, sodium alginate, carboxymethyl porous chestnut starch and calcium chloride are used to form a calcium alginate-containing gel network; under the action of a coupling agent, it is mixed with alginate ester and β-cyclodextrin to obtain a synergistic agent.

[0011] The synergistic agent encapsulates 2,4-dichlorophenoxyacetic acid, and the porous structure of carboxymethyl porous chestnut starch, combined with β-cyclodextrin inclusion, effectively increases the loading of 2,4-dichlorophenoxyacetic acid. The calcium alginate gel network and β-cyclodextrin cavity diffusion regulation form a sustained-release effect, effectively improving the sustained-release effect of the microcapsules. The action of sodium alginate, carboxymethyl porous chestnut starch, and alginate further prevents particle agglomeration and crystallization, improves the chemical stability of the microcapsules, further increases the retention rate of active ingredients, and reduces the capsule wall breakage rate. Finally, through the synergistic effect of the synergistic agent and other raw materials, the encapsulation efficiency, storage stability, and drug utilization rate of the microcapsules are significantly improved.

[0012] The gel network formed by the synergistic adjuvant encapsulates 2,4-dichlorophenoxyacetic acid within the network. When rainwater washes over it, the gel network resists the shear force of the water flow through steric hindrance and mechanical strength, reducing the loss of 2,4-dichlorophenoxyacetic acid. The porous framework of carboxymethyl porous chestnut starch restricts the migration and diffusion of 2,4-dichlorophenoxyacetic acid in rainwater through physical adsorption and chemical action. At the same time, the hydrophobic cavity of β-cyclodextrin encapsulates 2,4-dichlorophenoxyacetic acid, reducing the contact area between 2,4-dichlorophenoxyacetic acid molecules and water, thereby giving the prepared pesticide microcapsule suspension good resistance to rainwater washout.

[0013] The gel network formed by the synergist blocks some of the direct ultraviolet radiation, and the β-cyclodextrin cavity shields the light around the 2,4-dichlorophenoxyacetic acid molecules, thereby reducing the direct contact between photons and the active ingredient, thus giving the prepared pesticide microcapsule suspension good resistance to photodegradation.

[0014] Preferably, the emulsifier includes at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, sodium lignosulfonate, fatty alcohol polyoxyethylene ether, lauryl alcohol polyoxyethylene ether, and polyoxyethylene castor oil.

[0015] Preferably, the defoamer includes at least one of the following: tributyl phosphate, lignin sulfonate, alkyl naphthalene sulfonate formaldehyde condensate, naphthalene sulfonate, tristyrylphenol ethoxylate phosphate, fatty alcohol ethoxylate, alkylphenol polyoxyethylene ether, alkylphenol polyoxyethylene ether methyl ether condensate sulfate, fatty amine polyoxyethylene ether, and glycerol fatty acid ester polyoxyethylene ether.

[0016] Preferably, the diluent includes at least one of chlorobenzene, 1-butyl glycidyl ether, benzyl alcohol, ethyl acetate, or phenyl ethyl acetate.

[0017] Preferably, the dispersant comprises at least one of fatty alcohol polyoxyethylene ether, sorbitol polyoxyethylene ether, alkylphenol polyoxyethylene ether phosphate, tristyrylphenol polyoxyethylene ether, and naphthalene sulfonate formaldehyde condensate.

[0018] Secondly, this application provides a method for preparing pesticide microcapsule suspensions, using the following technical solution: A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Weigh out each ingredient according to the formula; Formaldehyde and urea are mixed, and the pH is adjusted to 9 with a 10% sodium oxide solution. The water bath temperature is increased to 70°C at 2°C / min and kept at that temperature for 1-2 hours to obtain a formaldehyde-urea prepolymer solution. Emulsifier, defoamer, diluent, synergist, dispersant, and water are added to 2,4-dichlorophenoxyacetic acid and mixed well to obtain an O / W type emulsion. Add formaldehyde-urea prepolymer solution to O / W type emulsion and mix. Mix at 60-80℃ for 1-3 hours. During the mixing process, add acidifying agent solution in batches to adjust the pH value to 2-3. Continue stirring at 200-400 rpm for 1-3 hours to complete the solidification process of microcapsules. Then add alkali adjusting agent solution to adjust the pH value to 5-7 to obtain pesticide microcapsule suspension.

[0019] Thirdly, this application provides an application of a pesticide microcapsule suspension as a herbicide, employing the following technical solution: Application of the above-mentioned pesticide microcapsule suspension as a herbicide.

[0020] In summary, this application includes at least one of the following beneficial technical effects: 1. The pesticide microcapsule suspension prepared in this application, by adding synergistic adjuvants, forms a cross-linked network structure, which can effectively encapsulate 2,4-dichlorophenoxyacetic acid, so that the prepared pesticide microcapsule suspension has good encapsulation rate, stability and efficacy utilization. 2. The pesticide microcapsule suspension prepared in this application has good resistance to photolysis and rainwater erosion. The pesticide microcapsule suspension can maintain high stability under light conditions, reducing the problem of pesticide failure due to photolysis. At the same time, under natural conditions such as rainwater erosion, the pesticide microcapsule suspension can effectively reduce pesticide loss and maintain the longevity of the efficacy. Detailed Implementation

[0021] 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.

[0022] All raw materials involved in this application are commercially available products, among which, 1-Butyl glycidyl ether, purchased from Merck; Tristyrene-based phenolic polyoxyethylene ether, CAS: 99734-09-5; α-Amylase (4000U / g) and glucose glucoamylase (100000U / g) were purchased from Shanghai Aladdin Reagent Co., Ltd. Petroleum ether, purchased from Shanghai Aladdin Reagent Co., Ltd. Sodium alginate (200±20 mpa.s) was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. β-Cyclodextrin, purchased from Sinopharm Chemical Reagent Co., Ltd.; The present application will be further described in detail below with reference to embodiments and comparative examples.

[0023] Raw material source:

[0024] Preparation of carboxymethyl porous chestnut starch: Add 5 times the volume of petroleum ether to the original chestnut starch and mix for 1 hour. Centrifuge and discard the supernatant. Add 5 times the volume of anhydrous ethanol and mix for 30 minutes. Centrifuge and discard the supernatant. Add 5 times the volume of sodium hydroxide (0.2% by mass) and mix for 1 hour. Centrifuge and discard the supernatant. Add 5 times the volume of distilled water and mix for 30 minutes. Centrifuge and discard the supernatant. Finally, freeze-dry the precipitate and pass it through a 100-mesh sieve to obtain chestnut starch.

[0025] Add 50 mL of citrate-sodium dihydrogen phosphate buffer solution with pH 5.6 to chestnut starch to obtain a starch slurry solution with a mass concentration of 19%. Preheat the starch slurry solution at 48℃ for 10 min, add a complex enzyme with a total enzyme activity of 1232 U / g, and react at 45℃ for 6 h. Centrifuge, wash with distilled water, and dry to obtain porous chestnut starch.

[0026] 100 mL of anhydrous ethanol was added to porous chestnut starch and reacted at 40 °C for 30 min. Sodium hydroxide was added and mixed for 20 min, followed by sodium chloroacetate and mixing for 40 min. The pH of the starch emulsion was adjusted to 6.5 with acetic acid. The mixture was then centrifuged, washed, and dried to obtain carboxymethyl porous chestnut starch.

[0027] The complex enzyme is a mixture of α-amylase and saccharifying enzyme, with a mass ratio of α-amylase to saccharifying enzyme of 2:3.

[0028] Based on the amount of monoglucose in porous chestnut starch, the molar ratio of sodium hydroxide to porous chestnut starch is 2.5:1; the molar ratio of sodium chloroacetate to porous chestnut starch is 3:1.

[0029] Preparation Example 1:

[0030] The preparation method of the synergistic agent is as follows: Mix 1g of sodium alginate with water to obtain a sodium alginate aqueous solution with a mass concentration of 5%. 1 g of carboxymethyl porous chestnut starch and a 5% sodium alginate aqueous solution were mixed for 20 minutes to obtain the first mixture; Add 2g of calcium chloride to 100mL of distilled water and mix well to obtain a calcium chloride solution; The first mixture was added to a calcium chloride solution and mixed for 30 minutes to obtain the second mixture; Add 3g of alginate to 50mL of distilled water and mix well. Then add 2g of β-cyclodextrin and mix for 40 minutes. Next, add the second mixture and 1.5g of coupling agent and mix for 30 minutes to obtain the synergistic agent.

[0031] The coupling agent is KH-550.

[0032] Alginate is hexadecyl alginate, with a degree of esterification of 15-18%.

[0033] Preparation Example 2:

[0034] The preparation method of the synergistic agent is as follows: Mix 0.5g of sodium alginate with water to obtain a 5% sodium alginate aqueous solution. 0.5g of carboxymethyl porous chestnut starch and a 5% sodium alginate aqueous solution were mixed for 20 minutes to obtain the first mixture; Add 1.5g of calcium chloride to 100mL of distilled water and mix well to obtain a calcium chloride solution; The first mixture was added to a calcium chloride solution and mixed for 30 minutes to obtain the second mixture; Add 2.5g of alginate to 50mL of distilled water and mix well. Then add 1.5g of β-cyclodextrin and mix for 40 minutes. Next, add the second mixture and 1g of coupling agent and mix for 30 minutes to obtain the synergistic agent.

[0035] The coupling agent is KH-550.

[0036] Alginate is hexadecyl alginate, with a degree of esterification of 15-18%.

[0037] Preparation Example 3:

[0038] The preparation method of the synergistic agent is as follows: 1.5g of sodium alginate and water were mixed to obtain a sodium alginate aqueous solution with a mass concentration of 5%. 1.5g of carboxymethyl porous chestnut starch and a 5% sodium alginate aqueous solution were mixed for 20 minutes to obtain the first mixture; Add 2.5g of calcium chloride to 100mL of distilled water and mix well to obtain a calcium chloride solution; The first mixture was added to a calcium chloride solution and mixed for 30 minutes to obtain the second mixture; Add 3.5g of alginate to 50mL of distilled water and mix well. Then add 2.5g of β-cyclodextrin and mix for 40 minutes. Next, add the second mixture and 2g of coupling agent and mix for 30 minutes to obtain the synergistic agent.

[0039] The coupling agent is KH-550.

[0040] Alginate is hexadecyl alginate, with a degree of esterification of 15-18%.

[0041] Example 1: A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Adding 16g of formaldehyde to water yields a formaldehyde aqueous solution with a mass concentration of 37%. Mix 5g of urea with a 37% formaldehyde aqueous solution, adjust the pH to 9 with a 10% sodium oxide solution, heat the water bath to 70℃ at 2℃ / min and keep it at that temperature for 1.5 hours, then dilute with distilled water to obtain a formaldehyde-urea prepolymer solution. Add 6g of emulsifier, 0.5g of defoamer, 3g of diluent, 13g of synergist, 3g of dispersant, and 100mL of water to 30g of 2,4-dichlorophenoxyacetic acid, and stir at 700rpm for 1h to obtain an O / W type emulsion. Formaldehyde-urea prepolymer solution was added to the O / W type emulsion and mixed at 70°C for 2 hours. During this stage, hydrochloric acid solution was added in batches to slowly adjust the pH to 2. Stirring was continued at 300 rpm for 2 hours to complete the solidification process of microcapsules. Finally, 10 wt% sodium hydroxide solution was added to adjust the pH of the system to 6 to obtain pesticide microcapsule suspension.

[0042] The emulsifier is a mixture of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether AEO-9, wherein the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether AEO-9 is 1:2.

[0043] The defoamer is tributyl phosphate.

[0044] The diluent is 1-butyl glycidyl ether.

[0045] The synergistic agent was prepared in Preparation Example 1.

[0046] The dispersant is tristyrylphenol polyoxyethylene ether.

[0047] Example 2:

[0048] A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Adding 7g of formaldehyde to water yields a formaldehyde aqueous solution with a mass concentration of 37%. Mix 2g of urea with a 37% formaldehyde aqueous solution, adjust the pH to 9 with a 10% sodium oxide solution, heat the water bath to 70℃ at 2℃ / min and keep it at that temperature for 1.5 hours, then dilute with distilled water to obtain a formaldehyde-urea prepolymer solution. Add 3g of emulsifier, 0.1g of defoamer, 2g of diluent, 10g of synergist, 2g of dispersant, and 100mL of water to 25g of 2,4-dichlorophenoxyacetic acid, and stir at 700rpm for 1h to obtain an O / W type emulsion. Formaldehyde-urea prepolymer solution was added to the O / W type emulsion and mixed at 70°C for 2 hours. During this stage, hydrochloric acid solution was added in batches to slowly adjust the pH to 2. Stirring was continued at 300 rpm for 2 hours to complete the solidification process of microcapsules. Finally, 10 wt% sodium hydroxide solution was added to adjust the pH of the system to 6 to obtain pesticide microcapsule suspension.

[0049] The emulsifier is a mixture of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether AEO-9, wherein the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether AEO-9 is 1:2.

[0050] The defoamer is tributyl phosphate.

[0051] The diluent is 1-butyl glycidyl ether.

[0052] The synergistic agent was prepared in Preparation Example 2.

[0053] The dispersant is tristyrylphenol polyoxyethylene ether.

[0054] Example 3:

[0055] A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Add 24.5g of formaldehyde to water to obtain a formaldehyde aqueous solution with a mass concentration of 37%; Mix 7g of urea with a 37% formaldehyde aqueous solution, adjust the pH to 9 with a 10% sodium oxide solution, heat the water bath to 70℃ at 2℃ / min and keep it at that temperature for 1.5 hours, then dilute with distilled water to obtain a formaldehyde-urea prepolymer solution. Add 9g of emulsifier, 1g of defoamer, 4g of diluent, 15g of synergist, 4g of dispersant, and 100mL of water to 35g of 2,4-dichlorophenoxyacetic acid, and stir at 700rpm for 1h to obtain an O / W type emulsion. Formaldehyde-urea prepolymer solution was added to the O / W type emulsion and mixed at 70°C for 2 hours. During this stage, hydrochloric acid solution was added in batches to slowly adjust the pH to 2. Stirring was continued at 300 rpm for 2 hours to complete the solidification process of microcapsules. Finally, 10 wt% sodium hydroxide solution was added to adjust the pH of the system to 6 to obtain pesticide microcapsule suspension.

[0056] The emulsifier is a mixture of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether AEO-9, wherein the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether AEO-9 is 1:2.

[0057] The defoamer is tributyl phosphate.

[0058] The diluent is 1-butyl glycidyl ether.

[0059] The synergistic agent was prepared in Preparation Example 3.

[0060] The dispersant is tristyrylphenol polyoxyethylene ether.

[0061] Example 4:

[0062] A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Adding 16g of formaldehyde to water yields a formaldehyde aqueous solution with a mass concentration of 37%. Mix 5g of urea with a 37% formaldehyde aqueous solution, adjust the pH to 9 with a 10% sodium oxide solution, heat the water bath to 70℃ at 2℃ / min and keep it at that temperature for 1.5 hours, then dilute with distilled water to obtain a formaldehyde-urea prepolymer solution. Add 6g of emulsifier, 0.5g of defoamer, 3g of diluent, 13g of synergist, 3g of dispersant, and 100mL of water to 30g of 2,4-dichlorophenoxyacetic acid, and stir at 700rpm for 1h to obtain an O / W type emulsion. Formaldehyde-urea prepolymer solution was added to the O / W type emulsion and mixed at 70°C for 2 hours. During this stage, hydrochloric acid solution was added in batches to slowly adjust the pH to 2. Stirring was continued at 300 rpm for 2 hours to complete the solidification process of microcapsules. Finally, 10 wt% sodium hydroxide solution was added to adjust the pH of the system to 6 to obtain pesticide microcapsule suspension.

[0063] The emulsifier is a mixture of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether AEO-9, wherein the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether AEO-9 is 1:2.

[0064] The defoamer is tributyl phosphate.

[0065] The diluent is 1-butyl glycidyl ether.

[0066] The synergistic agent was prepared in Preparation Example 2.

[0067] The dispersant is tristyrylphenol polyoxyethylene ether.

[0068] Example 5:

[0069] A method for preparing a pesticide microcapsule suspension, the preparation method comprising the following steps: Adding 16g of formaldehyde to water yields a formaldehyde aqueous solution with a mass concentration of 37%. Mix 5g of urea with a 37% formaldehyde aqueous solution, adjust the pH to 9 with a 10% sodium oxide solution, heat the water bath to 70℃ at 2℃ / min and keep it at that temperature for 1.5 hours, then dilute with distilled water to obtain a formaldehyde-urea prepolymer solution. Add 6g of emulsifier, 0.5g of defoamer, 3g of diluent, 13g of synergist, 3g of dispersant, and 100mL of water to 30g of 2,4-dichlorophenoxyacetic acid, and stir at 700rpm for 1h to obtain an O / W type emulsion. Formaldehyde-urea prepolymer solution was added to the O / W type emulsion and mixed at 70°C for 2 hours. During this stage, hydrochloric acid solution was added in batches to slowly adjust the pH to 2. Stirring was continued at 300 rpm for 2 hours to complete the solidification process of microcapsules. Finally, 10 wt% sodium hydroxide solution was added to adjust the pH of the system to 6 to obtain pesticide microcapsule suspension.

[0070] The emulsifier is a mixture of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether AEO-9, wherein the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether AEO-9 is 1:2.

[0071] The defoamer is tributyl phosphate.

[0072] The diluent is 1-butyl glycidyl ether.

[0073] The synergistic agent was prepared in Preparation Example 3.

[0074] The dispersant is tristyrylphenol polyoxyethylene ether.

[0075] Example 6:

[0076] The difference from Example 1 is that the amount of synergist added is 10g.

[0077] The synergistic agent was prepared in Preparation Example 1.

[0078] Example 7:

[0079] The difference from Example 1 is that the amount of synergist added is 15g.

[0080] The synergistic agent was prepared in Preparation Example 1.

[0081] Comparative Example 1: The difference from Example 1 is that the amount of synergist added is 9g.

[0082] The synergistic agent was prepared in Preparation Example 1.

[0083] Comparative Example 2:

[0084] The difference from Example 1 is that the amount of synergist added is 16g.

[0085] The synergistic agent was prepared in Preparation Example 1.

[0086] Comparative Example 3:

[0087] The difference from Example 1 is that no synergistic agent is added.

[0088] Comparative Example 4:

[0089] The difference from Example 1 is that the synergist is replaced with an equal weight of the synergist prepared by the following method.

[0090] The preparation method of the synergistic agent is as follows: Mix 1g of sodium alginate with water to obtain a sodium alginate aqueous solution with a mass concentration of 5%. 1 g of carboxymethyl porous chestnut starch and a 5% sodium alginate aqueous solution were mixed for 20 minutes to obtain a mixture. Add 2g of calcium chloride to 100mL of distilled water and mix well to obtain a calcium chloride solution; The mixture was added to a calcium chloride solution and mixed for 30 minutes to obtain the synergistic agent.

[0091] Performance testing: 1. Microcapsule encapsulation efficiency determination: Accurately weigh 1g of each of the pesticide microcapsule suspension samples prepared in the above examples and comparative examples, and place them in 100mL volumetric flasks respectively; add methanol-water solution to the volumetric flasks, with a methanol-water volume ratio of 1:1, and make up to 100mL, and let stand at room temperature for 30 minutes; take the liquid sample, centrifuge it, and measure the absorbance of the centrifuged liquid by ultraviolet spectrophotometry, and calculate the mass of the active ingredient M1 by referring to the standard curve; then sonicate the volumetric flask for 20min, remove the liquid sample, measure the absorbance of the centrifuged liquid by ultraviolet spectrophotometry, and calculate the mass of the active ingredient M2 by referring to the standard curve; then the encapsulation efficiency of the pesticide microcapsule suspension = (M2-M1) / mass of the pesticide microcapsule suspension sample.

[0092] 2. Stability test: The low-temperature stability and thermal storage stability of pesticide microcapsule suspension samples obtained in the examples and comparative examples were tested according to the national standard GB / T19136-2003 "Determination of Thermal Storage Stability of Pesticides".

[0093] 3. Photolysis resistance test: Take 10 mL of each of the pesticide microcapsule suspension samples prepared in the above examples and comparative examples, and evenly coat them on a glass plate, controlling the coating thickness to be uniform. Then place them in a forced-air drying oven at 40°C for 2 hours to form a pesticide film with a thickness of approximately 0.1 mm. Use a UV lamp with a wavelength of 365 nm and a power of 30 W to vertically irradiate the samples, ensuring that the vertical distance between the center of the lamp tube and the surface of the pesticide film is 20 cm. Turn on the light source for irradiation, and stop irradiation after 24 h, 48 h, and 72 h, respectively. Set up 3 parallel samples at each time point.

[0094] After each light exposure, the drug film was scraped off, dissolved in methanol, and ultrasonically extracted for 30 min. After filtration, the residual amount of 2,4-dichlorophenoxyacetic acid was determined by high-performance liquid chromatography (HPLC), and the degradation rate was calculated. The formula for calculating the degradation rate is as follows: ,

[0095] Where C0 is the initial concentration, C t This represents the concentration after illumination.

[0096] 4. Rainwater erosion resistance test: Prepare the medicine solution: The pesticide microcapsule suspension samples obtained in the examples and comparative examples were mixed with water to prepare a uniform solution with the active ingredient content of 0.1 wt%.

[0097] Drug spot preparation and initial characterization: Use a pipette to pick up 1 μL of each sample and drop it onto clean wheat leaves. Place each sample on three wheat leaf surfaces and dry them in a 30°C incubator for 3 hours until the solution completely forms a film. Take a picture of the dried slide under a microscope. Rainwater rinsing treatment: Wheat leaves with drug spots were placed at a 60-degree angle under a spray tower to simulate natural rain conditions. 1L of water was sprayed evenly. After spraying, the leaves were dried in a 30℃ incubator for 3 hours until there were no obvious water stains on the surface. The leaves were then photographed under a microscope. Data processing and computation: The area of ​​pesticide spots on wheat leaves before and after spraying was calculated using software, and the ratio of the pesticide spot area after spraying to the area before spraying was used to determine the rain resistance effect.

[0098] Table 1 Encapsulation efficiency and stability test results

[0099] As shown in Table 1, the pesticide microcapsule suspension prepared using the embodiments of this application has good encapsulation rate and good stability; this indicates that by adding synergistic adjuvants, the encapsulation rate, resistance to photolysis, and resistance to rainwater erosion of the pesticide microcapsule suspension are effectively improved.

[0100] Based on the test results of Examples 1, 6, 7, Comparative Example 1, and Comparative Example 2, it can be seen that the amount of synergist added affects the encapsulation efficiency, photolysis resistance, and rain erosion resistance of pesticide microcapsule suspensions. Furthermore, the encapsulation efficiency, photolysis resistance, and rain erosion resistance of pesticide microcapsule suspensions are optimal when the amount of synergist added is 10-15 parts by weight.

[0101] Based on the test results of Example 1 and Comparative Example 3, it can be seen that the encapsulation rate, resistance to photolysis, and resistance to rainwater erosion of Example 1 are all better than those of Comparative Example 3. This indicates that by adding synergistic adjuvants, the encapsulation rate, resistance to photolysis, and resistance to rainwater erosion of pesticide microcapsule suspensions in this application are effectively improved.

[0102] Based on the test results of Example 1 and Comparative Example 4, it can be seen that the encapsulation rate, photolysis resistance, and rain erosion resistance of Example 1 are all better than those of Comparative Example 4. This indicates that by improving the formulation of the synergistic adjuvant in this application, the encapsulation rate, photolysis resistance, and rain erosion resistance of the pesticide microcapsule suspension have been effectively improved.

[0103] 5. Field trials: The experimental field has a well-developed irrigation and drainage system, uniform field management measures, and moderate and evenly distributed soil fertility. Wheat was planted in the experimental field, and the target weed was shepherd's purse (an annual broadleaf weed).

[0104] Experimental Design: The experiment included a pesticide treatment group and a water control group, with each treatment replicated three times, resulting in a total of 24 experimental plots, each with an area of ​​30 m², arranged in a randomized block design. The water control group received only water spraying (without pesticide), while the remaining plots were pesticide treatment areas.

[0105] Application method: Apply the pesticide once during the wheat's greening stage. Prepare a uniform solution by diluting the formulation with 400 kg of water per hectare. Calculate the dosage for each plot and spray once.

[0106] Survey methods and indicators: Thirty days after application, the fresh weight control efficacy against the target weeds and the safety to wheat were investigated for each treatment. For the fresh weight control efficacy against weeds, four quadrats (0.25 m² each) were randomly selected from each plot. Annual weeds within the quadrats were removed, classified, and weighed by fresh weight. The control efficacy was calculated using the formula.

[0107] Control efficacy (%) = (fresh weight of weeds in blank control area - fresh weight of weeds in treatment area) / fresh weight of weeds in blank control area × 100%.

[0108] Table 2 Field Trial Results

[0109] As shown in Table 2, the pesticide microcapsule suspension prepared by the method of this application has a good control effect on shepherd's purse.

[0110] In addition, based on the observation of the entire field trial, the wheat fields grew well within the experimental dosage range, and no phytotoxicity was observed, indicating that the pesticide microcapsule suspension prepared by the method of this application does not cause phytotoxicity to wheat.

Claims

1. A pesticide microcapsule suspension, characterized in that: The microcapsules comprise the following raw materials in parts by weight: 2-7 parts urea, 7-24.5 parts formaldehyde, 3-9 parts emulsifier, 0.1-1 part defoamer, 2-4 parts diluent, 10-15 parts synergist, 2-4 parts dispersant, and 25-35 parts 2,4-dichlorophenoxyacetic acid. The synergistic additives include the following raw materials in parts by weight: 0.5-1.5 parts carboxymethyl porous chestnut starch, 0.5-1.5 parts sodium alginate, 1.5-2.5 parts calcium chloride, 2.5-3.5 parts alginate, 1.5-2.5 parts β-cyclodextrin, and 1-2 parts coupling agent.

2. The pesticide microcapsule suspension according to claim 1, characterized in that: The coupling agent is coupling agent KH-550.

3. The pesticide microcapsule suspension according to claim 1, characterized in that: The alginate is hexadecyl alginate with a degree of esterification of 15-18%.

4. The pesticide microcapsule suspension according to claim 1, characterized in that: The preparation method of the synergistic agent includes the following steps: Sodium alginate and water were mixed to obtain a sodium alginate aqueous solution with a mass fraction of 5%. Carboxymethyl porous chestnut starch and sodium alginate aqueous solution were mixed, and calcium chloride was added and mixed to obtain a mixture. Alginate and β-cyclodextrin are mixed, and then the mixture and coupling agent are added to obtain a synergistic agent.

5. The pesticide microcapsule suspension according to claim 1, characterized in that: The emulsifier includes at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, sodium lignosulfonate, fatty alcohol polyoxyethylene ether, lauryl alcohol polyoxyethylene ether, and polyoxyethylene castor oil.

6. The pesticide microcapsule suspension according to claim 1, characterized in that: The defoamer includes at least one of the following: tributyl phosphate, lignin sulfonate, alkyl naphthalene sulfonate formaldehyde condensate, naphthalene sulfonate, tristyrylphenol ethoxylate phosphate, fatty alcohol ethoxylate, alkylphenol polyoxyethylene ether, alkylphenol polyoxyethylene ether methyl ether condensate sulfate, fatty amine polyoxyethylene ether, and glycerol fatty acid ester polyoxyethylene ether.

7. The pesticide microcapsule suspension according to claim 1, characterized in that: The diluent includes at least one of chlorobenzene, 1-butyl glycidyl ether, benzyl alcohol, ethyl acetate, or phenyl ethyl acetate.

8. The pesticide microcapsule suspension according to claim 1, characterized in that: The dispersant includes at least one of fatty alcohol polyoxyethylene ether, sorbitol polyoxyethylene ether, alkylphenol polyoxyethylene ether phosphate, tristyrene-phenylphenol polyoxyethylene ether, and naphthalene sulfonate formaldehyde condensate.

9. A method for preparing the pesticide microcapsule suspension according to any one of claims 1-8, characterized in that: The preparation method steps are as follows: Weigh out each ingredient according to the formula; Formaldehyde and urea are mixed, and the pH is adjusted to 9 with a 10% sodium oxide solution. The temperature is increased to 70°C at 2°C / min and then kept at that temperature for 1-2 hours to obtain a formaldehyde-urea prepolymer solution. Emulsifier, defoamer, diluent, synergist, dispersant, and water are added to 2,4-dichlorophenoxyacetic acid and mixed well to obtain an O / W type emulsion. Add formaldehyde-urea prepolymer solution to O / W type emulsion and mix. Mix at 60-80℃ for 1-3 hours. During the mixing process, add acidifying agent solution in batches to adjust the pH value to 2-3. Continue stirring at 200-400 rpm for 1-3 hours to complete the solidification process of microcapsules. Then add alkali adjusting agent solution to adjust the pH value to 5-7 to obtain pesticide microcapsule suspension.

10. The application of a pesticide microcapsule suspension according to any one of claims 1-8 as a herbicide.

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