Azoxystrobin microcapsule suspension for aerial spraying and preparation device and method thereof

Abstract

The present application relates to a kind of azoxystrobin microcapsule suspending agent for aerial prevention and its preparation device, preparation method, which will be organic solvent, azoxystrobin raw drug, oily capsule material into oil phase feeding kettle and stir to dissolve;Deionized water, dispersing agent, emulsifying agent, defoaming agent are added into water phase feeding kettle and stir uniformly;Oil phase and water phase are respectively transported to pipeline shear machine, after being emulsion by shearing, it is transferred to finished product kettle;Deionized water, aqueous capsule material is stirred to dissolve in aqueous capsule material kettle;Aqueous capsule material solution is added dropwise into the emulsion of finished product kettle and carries out polymerization reaction;Additive is added afterwards, stir uniformly to obtain finished product.The present application will be oil phase material and water phase material simultaneously respectively added into pipeline shear machine, by adjusting flow, oil phase material and water phase material are simultaneously completed shearing, and the particle size distribution of microcapsule is controlled in a certain range, not only has excellent anti-drift property, but also significantly prolongs the persistence of azoxystrobin, avoids that azoxystrobin is prone to drug damage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pesticide dosage form processing, and particularly relates to a microcapsule suspension of azoxystrobin for aerial spraying and a preparation device and method thereof. BACKGROUND

[0002] Azoxystrobin is a strobilurin fungicide, which mainly inhibits the mitochondrial respiration of pathogenic fungi, so that the mitochondria of pathogenic fungi cannot produce and provide energy (ATP) required for normal cell metabolism, and eventually leads to cell death. Azoxystrobin has good activity against almost all fungal diseases (Ascomycota, Basidiomycota, Chytridiomycota and Deuteromycota), such as powdery mildew, rust, leaf blight, net blotch, downy mildew, and rice blast. It has protective, curative, penetrating and systemic activity, and is mainly used for cereals, rice, peanuts, grapes, potatoes, fruit trees, vegetables, coffee and lawns.

[0003] The systemic penetration of azoxystrobin is a double-edged sword, and improper use can easily cause pesticide damage: first, high application concentration can easily cause pesticide damage, and second, drift to other non-target crops during spraying can cause pesticide damage. When azoxystrobin is used on apple, pear, cherry, winter jujube and tomato, pesticide damage is easy to occur, and special attention is needed.

[0004] Generally, pesticides need to be sprayed onto the target by machinery, but with the transfer of land and rural labor, aerial spraying of pesticides has become the main measure for preventing and controlling pests in China due to its high operation efficiency, low plant protection cost and safety. The azoxystrobin pesticide used for aerial spraying generally adds a special adjuvant for aerial spraying to increase the settling rate and wetting type of droplets, prevent drift, and improve the absorption of pesticide solution. For example, Chinese patent CN108513975A discloses a azoxystrobin suspension for aerial spraying and a preparation method thereof. The azoxystrobin suspension adds a special adjuvant for aerial spraying to reduce the surface tension of droplets, increase the spreading area of droplets on crops, and improve the control efficiency of droplets. For another example, Chinese patent CN106665569A discloses a special adjuvant for aerial spraying. The adjuvant is suitable for suspension, oil suspension, water, emulsion, microemulsion and dry suspension formulations for aerial spraying, and has the effects of significantly preventing drift, promoting settling, increasing wetting and improving the absorption of pesticide solution in aerial spraying.

[0005] Although the above two adjuvants for aerial spraying have the characteristics of reducing the surface tension of pesticide solution and promoting the absorption of pesticide solution, due to the low dilution ratio, high concentration of pesticide solution and excessive absorption of azoxystrobin by crops (such as apple, pear, cherry, winter jujube and tomato), pesticide damage is easy to occur.

[0006] The azoxystrobin is prepared into the microcapsule suspension agent, and the problem of drug damage of high-concentration azoxystrobin can be effectively solved. The microcapsule suspension agent is prepared by chemical, physical or physical-chemical method, and solid or liquid original medicine is coated in the semi-permeable capsule wall material to form the microcapsule invisible to the naked eye and suspended in the system. Compared with the traditional dosage form, the following advantages are obtained: the coating of the capsule wall material enables the effective component in the microcapsule to be slowly released, and the persistence of the pesticide is prolonged; the active substance is wrapped in the capsule wall, the sensory stimulation of the original medicine component to the human body is effectively reduced, the drug damage to the crops is reduced, and the compounding of the pesticide is facilitated.

[0007] The microcapsule suspension agent is generally prepared by in-situ polymerization and interfacial polymerization. The microcapsule prepared by the in-situ polymerization is easy to agglomerate together, has poor dispersibility, and is easy to cause the phenomenon of clogging the nozzle in the aerial spraying process. The microcapsule suspension agent prepared by the interfacial polymerization has fast reaction speed, mild conditions, good dispersibility and high encapsulation rate. The traditional interfacial polymerization adopts in-tank shearing process, and the oil phase material is added into the water phase material while shearing. The oil phase material added in the early stage is repeatedly sheared, has a fine particle size, and has poor anti-drift performance. The oil phase material added in the late stage is insufficiently sheared, has a coarse particle size, and has insufficient capsule wall strength after the capsule is formed, and is easy to be broken.

[0008] A 26% azoxystrobin • cyazofamid microcapsule suspension agent and a preparation method thereof are disclosed in Chinese patent CN107318849A. The microcapsule suspension agent is prepared by in-situ polymerization, and the microcapsule is easy to agglomerate together, has poor dispersibility, and is easy to cause the phenomenon of clogging the nozzle in the aerial spraying process.

[0009] Therefore, there is an urgent need for an azoxystrobin microcapsule suspension agent for aerial spraying, which not only has good anti-drift performance, but also reduces the drug damage of azoxystrobin and prolongs the persistence. SUMMARY

[0010] The purpose of the present application is to provide an azoxystrobin microcapsule suspension agent for aerial spraying and a preparation device and method thereof. The prepared azoxystrobin microcapsule suspension agent has the effects of anti-drift, inhibition of evaporation, prolongation of persistence and reduction of drug damage of azoxystrobin.

[0011] The technical scheme adopted by the present application to solve the above problems is as follows: a preparation device for an azoxystrobin microcapsule suspension agent for aerial spraying, comprising an oil phase feeding kettle, a water phase feeding kettle, an aqueous capsule material kettle, a finished product kettle, an oil phase flow pump, a water phase flow pump, an aqueous capsule material pump and a pipeline type shearing machine, the oil phase feeding kettle is connected to the pipeline type shearing machine through the oil phase flow pump, the water phase feeding kettle is connected to the pipeline type shearing machine through the water phase flow pump, the pipeline type shearing machine is connected to the finished product kettle, and the aqueous capsule material kettle is connected to the finished product kettle through the aqueous capsule material flow pump.

[0012] Further, the oil phase feeding kettle, the water phase feeding kettle, the finished product kettle and the water-based capsule material kettle are each provided with a stirring device.

[0013] A preparation method of azoxystrobin microcapsule suspension for aerial prevention, comprising the following steps:

[0014] (1) Add an organic solvent into the oil phase feeding kettle, start stirring, add azoxystrobin into the oil phase feeding kettle, and stir until completely dissolved.

[0015] (2) Add the oil-based capsule material into the oil phase feeding kettle, stir until completely dissolved, and detect the density of the oil phase material.

[0016] (3) Add part of deionized water into the water phase feeding kettle, start stirring, add the dispersant, emulsifier and defoaming agent into the water phase feeding kettle, stir uniformly, and detect the density of the water phase material.

[0017] (4) Set the flow rates of the oil phase flow pump and the water phase flow pump according to the volume ratio of the oil phase material and the water phase material, the total flow rate of the oil phase material and the water phase material is 8-10 L / min, start the pipeline shear machine, the rotor linear speed of the shear machine is 28-35 m / s, so that the oil phase material and the water phase material are simultaneously sheared. Under the joint action of the emulsifier, the dispersant and the shear machine, the oil phase material and the water phase material form a uniform emulsion, and are transferred to the finished product kettle.

[0018] (5) Add deionized water into the water-based capsule material kettle, add the water-based capsule material while stirring, and stir until completely dissolved.

[0019] (6) Start stirring the finished product kettle at a speed of 100-200 r / min, start the water-based capsule material flow pump, set the flow rate to 20-500 mL / min, and add the water-based capsule material solution into the emulsion in the finished product kettle dropwise. The water-based capsule material and the oil-based capsule material perform polymerization reaction on the surface of the oil droplets in the emulsion, and form a dense capsule wall to cover the liquid capsule core.

[0020] (7) After the dropwise addition is completed, reduce the stirring speed, continue stirring at a speed of 30-60 r / min for 30 minutes, so that the capsule wall reaction is completely and the stability of the capsule wall is increased.

[0021] (8) Add the antifreezing agent, thickening agent and preservative into the finished product kettle, stir uniformly, and obtain the finished product.

[0022] Further, the mass percentage of each component of the azoxystrobin microcapsule suspension agent is as follows: azoxystrobin raw material: 1% to 15%, organic solvent: 2% to 40%, oily capsule material: 0.5% to 5%, aqueous capsule material: 0.2% to 2%, dispersant: 0.5% to 5%, emulsifier: 1% to 10%, defoaming agent: 0.1% to 2%, antifreeze agent: 0.5% to 5%, thickening agent: 0.05% to 0.2%, preservative: 0.05% to 1%, and deionized water: the rest to 100%.

[0023] Further, the organic solvent is one or more of ethyl acetate, acetonitrile, dichloromethane, methanol, toluene, acetone, 150# solvent oil, 200# solvent oil, and 1500# solvent oil.

[0024] Further, the oily capsule material is one or more of terephthaloyl chloride, polyacyl chloride, poly sulfuryl chloride, polychlorinated formate, isocyanate, diisocyanate, and polyisocyanate.

[0025] Further, the aqueous capsule material is one or more of ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, glycerol, and pentaerythritol.

[0026] Further, the dispersant is one or more of fatty alcohol polyoxyethylene ether sulfate, fatty alcohol, lignin sulfonate, alkylphenol polyoxyethylene ether formaldehyde condensate, alkylphenol polyoxyethylene ether sulfate, phenylethyl phenol polyoxyethylene ether, sodium alkyl naphthalene sulfonate, N-methyl taurine sodium salt, alkylphenol polyoxyethylene ether, succinic ester sulfonate, petroleum sulfonate sodium, polyvinyl alcohol, vinyl pyrrolidone, and carboxymethyl cellulose.

[0027] Further, the emulsifier is one or more of ethylene oxide propylene oxide copolymer, polyacrylamide, fatty amine salt, Tween, Span, polyacrylamide, polyglycerol ester, sorbitan monooleate, castor oil polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0028] Further, the defoaming agent is one or more of polydimethylsiloxane, silicone fat, emulsified silicone oil, high-carbon alcohol fatty acid ester complex, and polyoxyethylene polyoxypropane pentaerythritol ether.

[0029] Further, the antifreeze agent is one or more of propylene glycol, ethylene glycol, glycerol, and polyethylene glycol.

[0030] Further, the thickening agent is one or more of xanthan gum, polyvinyl alcohol, and sodium carboxymethyl cellulose.

[0031] Further, the preservative is one or more of carzone, benzoic acid, and sodium benzoate.

[0032] Further, the oil droplet particle size D50 in the emulsion prepared in step (4) is >10 μm, and D98 is <20 μm.

[0033] Further, the amount of deionized water added in step (5) is 10 times the weight of the aqueous capsule material.

[0034] A microcapsule suspension of azoxystrobin for aerial spraying is prepared by the above preparation method, and the particle size of the microcapsule is D50 >10 μm, and D98 <22 μm.

[0035] Compared with the prior art, the advantages of the present application are:

[0036] (1) In the present application, azoxystrobin is prepared into a microcapsule suspension, and after spraying, the active ingredient of azoxystrobin is blocked by the capsule wall material on the crop leaves, which can be slowly released, thereby prolonging the effective period and reducing the drug damage.

[0037] (2) In the present application, the microcapsule suspension of azoxystrobin is prepared by an interfacial polymerization method, which has good dispersibility and avoids the phenomenon of agglomeration of microcapsules prepared by in-situ polymerization and clogging of the spray head during aerial spraying.

[0038] (3) In the present application, the flow rates of the oil phase flow pump and the water phase flow pump are adjusted (the total flow rate of the oil phase material and the water phase material is controlled to be 8-10 L / min), so that the oil phase material and the water phase material are simultaneously sheared, and the rotor linear speed of the shearing machine is controlled to be 28-35 m / s, so that the emulsion particle size of the microcapsule suspension semi-finished product prepared is D50 >10 μm, and D98 <20 μm, and the particle size of the microcapsule suspension finished product is D50 >10 μm, and D98 <22 μm, which has good stability over time and strong anti-drift performance, and avoids the defects of the existing tank shearing method for preparing microcapsule suspensions, such as excessive shearing of the front-stage material, too fine particle size, poor anti-drift performance, insufficient shearing of the rear-stage material, too large particle size, low microcapsule wall strength, and easy breakage. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a preparation device structure diagram of the microcapsule suspension of azoxystrobin.

[0040] Among them: 1 is the oil phase feeding kettle, 2 is the water phase feeding kettle, 3 is the oil phase flow pump, 4 is the water phase flow pump, 5 is the pipeline type shearing machine, 6 is the finished product kettle, 7 is the water phase capsule material flow pump, and 8 is the water phase capsule material kettle.

[0041] Figure 2 It is a process flow diagram for preparing the microcapsule suspension of azoxystrobin by the tank shearing method.

[0042] Figure 3 It is a process flow diagram for preparing the microcapsule suspension of azoxystrobin by the tank shearing method. DETAILED DESCRIPTION

[0043] The application will be further described in detail below with reference to the embodiments of the drawings.

[0044] As Figure 1 The preparation device structure diagram of the azoxystrobin microcapsule suspension agent of the application is shown.

[0045] Example 1

[0046] A preparation device of an azoxystrobin microcapsule suspension agent for aerial spraying, comprising an oil phase feeding kettle 1, a water phase feeding kettle 2, the oil phase feeding kettle 1 is connected with a pipeline shear machine 5 through an oil phase flow pump 3, the water phase feeding kettle 2 is connected with the pipeline shear machine 5 through a water phase flow pump 4, the pipeline shear machine 5 is connected with a finished product kettle 6, and an aqueous capsule material kettle 8 is connected with the finished product kettle 6 through an aqueous capsule material flow pump 7.

[0047] Further, the oil phase feeding kettle 1, the water phase feeding kettle 2, the finished product kettle 6 and the aqueous capsule material kettle 8 are all provided with stirring devices.

[0048] The mass ratio of each component of the 10% azoxystrobin microcapsule suspension agent is as follows:

[0049] Azoxystrobin technical material (98.0%): 1020g

[0050] Ethyl acetate (organic solvent): 2200g

[0051] Terephthaloyl chloride (oily capsule material): 160g

[0052] Hexanediol (aqueous capsule material): 40g

[0053] Fatty alcohol polyoxyethylene ether sulfate (dispersant): 250g

[0054] Ethylene oxide propylene oxide copolymer (emulsifier): 400g

[0055] Polydimethylsiloxane (antifoaming agent): 50g

[0056] Propylene glycol (antifreeze): 200g

[0057] Xanthan gum (thickening agent): 20g

[0058] Kathon BIT 20 (preservative): 30g

[0059] Deionized water (continuous phase): 5630g

[0060] Total: 10000g

[0061] A preparation method of a 10% azoxystrobin microcapsule suspension agent for aerial spraying, comprising the following steps:

[0062] (1) Put 2200 g of ethyl acetate into the oil phase feeding kettle, start stirring, and add 1020 g of azoxystrobin technical material into the oil phase feeding kettle, and stir until completely dissolved.

[0063] (2) Put 160 g of terephthaloyl chloride into the oil phase feeding kettle, and stir until completely dissolved. The density of the oil phase material is 0.986 g / mL, so the volume of the oil phase material is 3.43 L.

[0064] (3) Put 5230 g of deionized water into the water phase feeding kettle, start stirring, and add 250 g of fatty alcohol polyoxyethylene ether sulfate, 400 g of ethylene oxide propylene oxide copolymer, and 50 g of polydimethylsiloxane into the water phase feeding kettle, and stir until uniform. The density of the water phase material is 1.045 g / mL, so the volume of the water phase material is 5.67 L.

[0065] (4) Set the flow rate of the oil phase flow pump to 3.43 L / min and the flow rate of the water phase flow pump to 5.67 L / min according to the volume ratio of the oil phase material to the water phase material, start the pipeline shear machine with a rotor linear speed of 30 m / s, and under the combined action of the emulsifiers, dispersants, and shear machine, a uniform emulsion is prepared. The oil droplet particle size in the emulsion is D50>10 μm and D98<20 μm. The emulsion is transferred to the finished product kettle through the shear machine.

[0066] (5) Add 400 g of deionized water to the water-based capsule kettle, and while stirring, add 40 g of hexylene glycol, and stir until completely dissolved.

[0067] (6) Start the agitator of the finished product kettle and set the stirring speed to 150 r / min, start the water-based capsule flow pump and set the flow rate to 30 mL / min, and add the water-based capsule solution to the emulsion in the finished product kettle. The water-based capsule and the oil-based capsule perform a polymerization reaction on the surface of the oil droplets in the emulsion to form a dense capsule wall that encapsulates the liquid capsule core.

[0068] (7) After the addition is complete, reduce the stirring speed to 50 r / min and continue stirring for 30 minutes to completely react the capsule wall and increase the stability of the capsule wall.

[0069] (8) Add 200 g of propylene glycol, 20 g of xanthan gum, and 30 g of Casson BIT 20 to the finished product kettle, and stir until uniform to obtain the finished product.

[0070] Example 2

[0071] The mass ratio of each component of the 15% azoxystrobin microcapsule suspension is as follows:

[0072] Azoxystrobin technical material (98.0%): 1531 g

[0073] Ethyl acetate (organic solvent): 3300 g

[0074] Terephthaloyl chloride (oil phase material): 200 g

[0075] Hexanediol (aqueous phase material): 50 g

[0076] Fatty alcohol polyoxyethylene ether sulfate (dispersant): 300 g

[0077] Ethylene oxide propylene oxide copolymer (emulsifier): 500 g

[0078] Polydimethylsiloxane (antifoaming agent): 50 g

[0079] Propylene glycol (antifreeze): 200 g

[0080] Xanthan gum (thickening agent): 20 g

[0081] Kathon BIT 20 (preservative): 30 g

[0082] Deionized water (continuous phase): 3819 g

[0083] Total: 10000 g

[0084] A preparation method of a 10% azoxystrobin microcapsule suspension for aerial spraying, comprising the following steps:

[0085] (1) Add 3300 g of ethyl acetate to the oil phase feeding kettle, start stirring, and add 1531 g of azoxystrobin technical material to the oil phase feeding kettle, stir until completely dissolved.

[0086] (2) Add 200 g of terephthaloyl chloride to the oil phase feeding kettle, stir until completely dissolved. The density of the oil phase material is 0.986 g / mL, and the volume of the oil phase material is 5.10 L.

[0087] (3) Add 3319 g of deionized water to the water phase feeding kettle, start stirring, and add 300 g of fatty alcohol polyoxyethylene ether sulfate, 500 g of ethylene oxide propylene oxide copolymer, and 50 g of polydimethylsiloxane to the water phase feeding kettle, and stir evenly. The density of the water phase material is 1.047 g / mL, and the volume of the water phase material is 3.98 L.

[0088] (4) According to the volume ratio of the oil phase material and the water phase material, set the flow rate of the oil phase flow pump to 5.10 L / min and the flow rate of the water phase flow pump to 3.98 L / min, start the pipeline shear machine, and the rotor linear speed of the shear machine is 33 m / s. The oil phase material and the water phase material are uniformly emulsified under the joint action of the emulsifier, the dispersant and the shear machine. The oil droplet particle size in the emulsion is D50>10 μm and D98<20 μm. The emulsion is transferred to the finished product kettle through the shear machine.

[0089] (5) Add 500 g of deionized water into the water-based capsule material kettle, and add 50 g of hexylene glycol while stirring until completely dissolved.

[0090] (6) Turn on the stirring machine of the finished product kettle and set the stirring speed to 150 r / min. Turn on the water-based capsule material flow pump and set the flow rate to 30 mL / min. Add the water-based capsule material solution to the emulsion in the finished product kettle. The water-based capsule material and the oily capsule material undergo polymerization reaction on the surface of the oil droplets in the emulsion to form a dense capsule wall, which encapsulates the liquid capsule core.

[0091] (7) After the addition is complete, reduce the stirring speed to 50 r / min and continue stirring for 30 minutes to complete the capsule wall reaction and increase the stability of the capsule wall.

[0092] (8) Add 200 g of propylene glycol, 20 g of xanthan gum, and 30 g of Casson BIT 20 into the finished product kettle and stir until uniform to obtain the finished product.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that in step (4), the oil phase flow pump flow rate is set to 2.80 L / min, the water phase flow pump flow rate is set to 4.63 L / min, and the rotor linear speed of the shear machine is 24 m / s.

[0095] The oil droplet particle size in the emulsion prepared in step (4) is (D50 > 15 μm, D98 < 30 μm).

[0096] Comparative Example 2

[0097] The difference from Example 1 is that in step (4), the oil phase flow pump flow rate is set to 2.80 L / min, the water phase flow pump flow rate is set to 4.63 L / min, and the rotor linear speed of the shear machine is 40 m / s.

[0098] The oil droplet particle size in the emulsion prepared in step (4) is (D50 > 5 μm, D98 < 10 μm).

[0099] Comparative Example 3

[0100] The difference from Example 2 is that in step (4), the oil phase flow pump flow rate is set to 4.00 L / min, the water phase flow pump flow rate is set to 3.12 L / min, and the rotor linear speed of the shear machine is 23 m / s.

[0101] The oil droplet particle size in the emulsion prepared in step (4) is (D50 > 15 μm, D98 < 30 μm).

[0102] Comparative Example 4

[0103] The difference from Example 2 is that in step (4), the oil phase flow pump flow rate is set to 4.00 L / min, the water phase flow pump flow rate is 3.12 L / min, and the shear machine rotor linear velocity is 38 m / s.

[0104] The oil droplet particle size in the emulsion prepared in step (4) is (D50 > 5 μm, D98 < 10 μm).

[0105] Comparative Example 5

[0106] The azoxystrobin microcapsule suspension concentrate is prepared by the in-tank shearing method with the same formulation composition as in Example 1.

[0107] As shown in the process flow chart for preparing the azoxystrobin microcapsule suspension concentrate by the in-tank shearing method. Figure 2

[0108] The 10% azoxystrobin microcapsule suspension concentrate is prepared by the in-tank shearing method, including the following steps:

[0109] (1) 2200 g of ethyl acetate is added to the oil phase feeding kettle, and stirring is started. 1020 g of azoxystrobin technical material is added to the oil phase feeding kettle, and stirring is continued until complete dissolution.

[0110] (2) 160 g of terephthaloyl chloride is added to the oil phase feeding kettle, and stirring is continued until complete dissolution.

[0111] (3) 5230 g of deionized water is added to the water phase feeding kettle, and stirring is started. 250 g of fatty alcohol polyoxyethylene ether sulfate, 400 g of ethylene oxide propylene oxide copolymer, and 50 g of polydimethylsiloxane are added to the water phase feeding kettle, and stirring is continued until uniform.

[0112] (4) The shear machine in the water phase feeding kettle is started, with a rotor linear velocity of 23 m / s. The flow pump 1 flow rate is set to 4.0 L / min. The oil phase material is slowly added to the water phase feeding kettle. The oil phase material and the water phase material are subjected to the combined action of the emulsifier, the dispersant, and the shear machine to produce a uniform emulsion. The oil droplet particle size in the emulsion is (9 μm < D50 < 10 μm). After shearing is completed, the flow pump 2 is started, and the emulsion is transferred to the product kettle.

[0113] (5) 400 g of deionized water is added to the water-based capsule material kettle, and 40 g of hexylene glycol is added while stirring until complete dissolution.

[0114] (6) The product kettle stirrer is started, with a stirring speed set to 150 r / min. The flow pump 3 is started, with a flow rate set to 30 mL / min. The water-based capsule material solution is added dropwise to the emulsion in the product kettle. The water-based capsule material and the oil-based capsule material undergo a polymerization reaction on the surface of the oil droplets in the emulsion, forming a dense capsule wall that encapsulates the liquid capsule core. ​

[0115] (7) After the addition is completed, the stirring speed is reduced, and stirring is continued at 50 r / min for 30 minutes to complete the capsule wall reaction and increase the stability of the capsule wall.

[0116] (8) 200 g of propylene glycol, 20 g of xanthan gum, and 30 g of Calsium BIT 20 are added to the product kettle and stirred uniformly to obtain the product.

[0117] Comparative Example 6

[0118] The formulation composition and preparation method are the same as those of Comparative Example 5, except that in step (4), the shear machine in the water phase feeding kettle is started, the rotor linear speed of the shear machine is 33 m / s, flow pump 1 is started, the flow rate is set to 4.0 L / min, the oil phase material is added to the water phase feeding kettle, and the oil phase material and the water phase material are uniformly emulsified under the joint action of the emulsifier, the dispersant, and the shear machine. The oil droplet particle size in the emulsion is (19 μm < D98 < 20 μm). After shearing is completed, flow pump 2 is started, and the emulsion is transferred to the product kettle.

[0119] Comparative Example 7

[0120] The formulation composition is the same as that of Example 2, and the in-tank shearing method is used to prepare azoxystrobin microcapsule suspending agent.

[0121] The in-tank shearing method is used to prepare 15% azoxystrobin microcapsule suspending agent, including the following steps:

[0122] (1) 3300 g of ethyl acetate is added to the oil phase feeding kettle, and stirring is started. 1531 g of azoxystrobin technical material is added to the oil phase feeding kettle, and stirring is continued until complete dissolution.

[0123] (2) 200 g of terephthaloyl chloride is added to the oil phase feeding kettle, and stirring is continued until complete dissolution.

[0124] (3) 3319 g of deionized water is added to the water phase feeding kettle, and stirring is started. 300 g of fatty alcohol polyoxyethylene ether sulfate, 500 g of ethylene oxide propylene oxide copolymer, and 50 g of polydimethylsiloxane are added to the water phase feeding kettle, and stirring is continued until uniform.

[0125] (4) The shear machine in the water phase feeding kettle is started, the rotor linear speed of the shear machine is 20 m / s, the flow rate of flow pump 1 is set to 4.0 L / min, the oil phase material is slowly added to the water phase feeding kettle, and the oil phase material and the water phase material are uniformly emulsified under the joint action of the emulsifier, the dispersant, and the shear machine. The oil droplet particle size in the emulsion is (9 μm < D50 < 10 μm). After shearing is completed, flow pump 2 is started, and the emulsion is transferred to the product kettle.

[0126] (5) Add 500 g of deionized water into the water-based capsule material kettle, and add 50 g of hexanediol while stirring until completely dissolved.

[0127] (6) Turn on the stirring machine of the finished product kettle, set the stirring speed to 150 r / min, start the flow pump 3, set the flow rate of the flow pump 3 to 30 mL / min, and add the water-based capsule material solution to the emulsion in the finished product kettle. The water-based capsule material and the oily capsule material undergo a polymerization reaction on the surface of the oil droplets in the emulsion to form a dense capsule wall, enclosing the liquid capsule core.

[0128] (7) After the addition is complete, reduce the stirring speed to continue stirring at 50 r / min for 30 minutes to complete the capsule wall reaction and increase the stability of the capsule wall.

[0129] (8) Add 200 g of propylene glycol, 20 g of xanthan gum, and 30 g of carboxymethyl cellulose to the finished product kettle and stir until uniform to obtain the finished product.

[0130] Comparative Example 8

[0131] The formulation composition and preparation method are the same as those of Comparative Example 7, except that in step (4), the shear machine in the water phase feeding kettle is turned on, the rotor linear speed of the shear machine is 30 m / s, the flow pump 1 is started, and the flow rate is set to 4.0 L / min. The oil phase material is added to the water phase feeding kettle, and the oil phase material and the water phase material are uniformly emulsified under the combined action of the emulsifier, the dispersant, and the shear machine. The oil droplet particle size in the emulsion is 19 μm < D98 < 20 μm. After shearing is completed, the flow pump 2 is started to transfer the emulsion to the finished product kettle.

[0132] Comparative Example 9

[0133] The mass ratio of each component of the conventional 10% azoxystrobin suspension agent is as follows:

[0134] Azoxystrobin technical material (98.0%): 1020 g

[0135] Sodium alkyl benzene sulfonate (wetting agent): 150 g

[0136] Polycarboxylate (dispersant): 250 g

[0137] Magnesium aluminum silicate (suspending agent): 150 g

[0138] Polydimethylsiloxane (antifoaming agent): 50 g

[0139] Propylene glycol (antifreeze): 200 g

[0140] Xanthan gum (thickening agent): 20 g

[0141] Carboxymethyl cellulose (preservative): 30 g

[0142] Deionized water (continuous phase): 8130 g

[0143] Total: 10000 g

[0144] As shown in the process flow chart for preparing azoxystrobin suspension concentrate by sand mill method. Figure 3

[0145] The preparation method of conventional type 10% azoxystrobin suspension concentrate includes the following steps:

[0146] (1) Add 8130 g of water to the feeding kettle, start stirring, and add 150 g of sodium alkyl benzene sulfonate, 250 g of polycarboxylate, 150 g of magnesium aluminum silicate, and 50 g of polydimethylsiloxane in turn, and stir uniformly.

[0147] (2) Add 1020 g of azoxystrobin technical material to the feeding kettle and stir uniformly.

[0148] (3) Start the material feeding pump and set the flow rate to 0.35 L / min. The above mixed material is transported to the sand mill for grinding, and the sand mill rotates at 800 r / min to obtain suspension concentrate semi-product, which is then transferred to the finished product kettle. The particle size of the semi-product is D50>10 μm and D98<20 μm.

[0149] (4) Add 200 g of propylene glycol, 20 g of xanthan gum, and 30 g of Kathon BIT 20 to the finished product kettle in turn, and stir uniformly to obtain the finished product.

[0150] Comparative Example 10

[0151] The mass ratio of each component of conventional type 15% azoxystrobin suspension concentrate is as follows:

[0152] Azoxystrobin technical material (98.0%): 1531 g

[0153] Sodium alkyl benzene sulfonate (wetting agent): 200 g

[0154] Polycarboxylate (dispersant): 300 g

[0155] Magnesium aluminum silicate (suspending agent): 100 g

[0156] Polydimethylsiloxane (antifoaming agent): 50 g

[0157] Propylene glycol (antifreeze): 200 g

[0158] Xanthan gum (thickening agent): 20 g

[0159] Kathon BIT 20 (preservative): 30 g

[0160] Deionized water (continuous phase): 7569 g

[0161] Total: 10000 g​

[0162] As shown in Figure 3 The process flow chart for preparing azoxystrobin suspension concentrate by sand mill method.

[0163] The preparation method of conventional type 15% azoxystrobin suspension concentrate comprises the following steps:

[0164] (1) 7569g of water was added to the feeding kettle, and stirring was started, and 200g of sodium alkyl benzene sulfonate, 300g of polycarboxylate, 150g of magnesium aluminum silicate, and 50g of polydimethylsiloxane were sequentially added and stirred uniformly.

[0165] (2) 1531g of azoxystrobin technical material was added to the feeding kettle and stirred uniformly.

[0166] (3) The feeding pump was started, and the flow rate was set to 0.35L / min, and the above-mentioned mixed material was transported to the sand mill for grinding, and the sand mill speed was 850r / min, to obtain the suspension concentrate semi-product, which was transferred to the finished product kettle, and the semi-product particle size (D50>10μm, D98<20μm).

[0167] (4) 200g of propylene glycol, 20g of xanthan gum, and 30g of Casson BIT 20 were sequentially added to the finished product kettle and stirred uniformly to obtain the finished product.

[0168] The physical and chemical indexes of Example 1 (10% azoxystrobin microcapsule suspension concentrate) and the corresponding comparative examples are shown in Table 1 below:

[0169] Table 1 Comparison of physical and chemical data of Example 1 and Comparative Examples 1, 2, 5, 6, 9

[0170]

[0171] As can be seen from the data in Table 1, Comparative Example 1 and Comparative Example 5 have larger microcapsule size, insufficient capsule wall strength, easy to rupture, decreased coating rate during long-term storage, and part of the core flows out, resulting in layering.

[0172] The physical and chemical indexes of Example 2 (15% azoxystrobin microcapsule suspension concentrate) and the corresponding comparative examples are shown in the table below:

[0173] Table 2 Comparison of physical and chemical data of Example 2 and Comparative Examples 3, 4, 7, 8, 10

[0174]

[0175] As can be seen from the data in Table 2, Comparative Example 3 and Comparative Example 7 have larger microcapsule size, insufficient capsule wall strength, easy to rupture, decreased coating rate during long-term storage, and part of the core flows out, resulting in layering.

[0176] Field flying prevention spray test:

[0177] Formulation of the agent: Examples 1-2, Comparative Examples 1-10 diluted 5 times

[0178] Spraying object: rice

[0179] Spraying equipment: unmanned aerial vehicle (Qingdao Zhi Fei Unmanned Aerial Vehicle Aviation Technology Development Co., Ltd.)

[0180] Spraying width: 5 m

[0181] Drug loading: 10 L

[0182] Wind direction and speed: east wind 2

[0183] Each test plot unit size is uniform, 10 m wide and 100 m long, divided into east and west zones, each 5 m wide. On the test day, it was an east wind, so the east zone was used as the spraying area and the west zone was used as the drift observation area. In order to avoid interference between units, each unit is at least 10 m apart.

[0184] After the unmanned aerial vehicle is loaded with the drug solution, the spraying pressure is set to 3 bar, the flight speed is 6 km / h, the flight height is 2 m, and the spraying is carried out along a straight line to the end point. The unmanned aerial vehicle operates normally, and the pesticide application in each unit is basically free of deviation.

[0185] In order to compare the drift resistance of each product, after spraying, when the leaves are slightly dry, 5 points are randomly taken in the spraying area and the drift observation area, each with an area of 0.36 m2 (60 cm x 60 cm). The active ingredient of azoxystrobin on the leaves is extracted with acetonitrile, and high performance liquid chromatography is used for detection to obtain the deposition amount of azoxystrobin in each area. The detection data are as follows:

[0186] Table 3 Examples 1 (10% azoxystrobin microcapsule suspension) and corresponding comparative examples

[0187] Comparison table of azoxystrobin deposition amount on rice leaves in each area

[0188]

[0189] The greater the azoxystrobin deposition amount in the drift observation area, the worse the drift resistance of the preparation. The data in Table 3 show that Comparative Example 1 and Comparative Example 5 have poor drift resistance due to the rupture of some microcapsules with too large size, generating small droplets. Comparative Example 2 has a small particle size and poor drift resistance, and Comparative Example 6 has a wide particle size distribution range and poor drift resistance of small droplets in the system.

[0190] Table 4 Example 2 (15% azoxystrobin microcapsule suspension) and corresponding comparative examples

[0191] Comparison table of azoxystrobin deposition amount on rice leaves in each area

[0192] The greater the azoxystrobin deposition amount in the drift observation area, the worse the drift resistance of the preparation. The data in Table 3 show that Comparative Example 1 and Comparative Example 5 have poor drift resistance due to the rupture of some microcapsules with too large size, generating small droplets. Comparative Example 2 has a small particle size and poor drift resistance, and Comparative Example 6 has a wide particle size distribution range and poor drift resistance of small droplets in the system.

[0193] The data in Table 4 shows that the anti-drift performance of the small droplets is poor for Comparative Example 3 and Comparative Example 7 because the size of the microcapsules is too large and the microcapsules are broken. The anti-drift performance of Comparative Example 4 is poor because the particle size is small. The anti-drift performance of the small droplets in the system is poor for Comparative Example 8 because the particle size distribution range is wide.

[0194] In order to compare the effective ingredient persistence of each product, samples were taken in the spraying area on the 1st day, the 5th day, the 10th day and the 15th day. Five points were randomly selected in each sampling area with an area of 0.36 m2(60 cm x 60 cm). The azoxystrobin effective ingredient on the leaves was extracted with acetonitrile, and high performance liquid chromatography was used for detection to obtain the deposition amount of the azoxystrobin effective ingredient in the spraying area of each test unit. The detection data are as follows:

[0195] Table 5 Comparison of azoxystrobin deposition on rice leaves at different periods of time for Example 1-2 and Comparative Examples 1-10

[0196]

[0197] As can be seen from the data in Table 5, the persistence of the microcapsule suspension agent is significantly longer than that of the ordinary suspension agent.

[0198] In order to compare the phytotoxicity of different products on rice, the disease index of the rice plants in each test unit was investigated 15 days after spraying. Five points were selected in each area, and 50 plants were selected in each point.

[0199] Classification method:

[0200] 0 level: no disease;

[0201] 1 level: less than 5 disease patches, and the length of the disease patch is less than 1 cm;

[0202] 3 level: 6-10 disease patches, and the length of part of the disease patch is more than 1 cm;

[0203] 5 level: 11-25 disease patches, and part of the disease patches are connected to form a patch, and the leaf area is 10-25%;

[0204] 7 level: more than 26 disease patches; the disease patches are connected to form a patch, and the leaf area is 26-50%;

[0205] 9 level: the disease patches are connected to form a patch, and the leaf area is more than 50% or the whole leaf dies.

[0206] The control effect was calculated according to the following formula:

[0207] Disease index = ∑(number of plants at each level x value of the disease level) / (total number of plants surveyed x value of the highest level) x 100

[0208] Table 6 Disease investigation results of the sprayed rice for Example 1-2 and Comparative Examples 1-10

[0209]

[0210] From the data of Table 6, it can be seen that at the same application concentration, the disease index of the crops is significantly lower than that of the ordinary suspension agent due to the slow-release performance of the microcapsule suspension agent.

[0211] The present application uses the interface polymerization method to prepare the azoxystrobin into the microcapsule suspension agent, significantly prolongs the effective period, and solves the problem of drug damage of azoxystrobin, effectively controls the particle size distribution of the microcapsule through the pipeline shear process, and overcomes the phenomenon that the pesticide solution is easy to drift during aerial spraying.

[0212] In addition to the above-mentioned embodiments, the present application also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the claims of the present application.

Claims

1. A process for the preparation of azoxystrobin microcapsule suspension concentrate for aerial application, characterized by: Comprising the following steps: (1) 2200g of ethyl acetate was added to the oil phase feeding kettle, and stirring was started. 1020g of azoxystrobin technical material was added to the oil phase feeding kettle, and stirring was continued until complete dissolution; (2) 160g of terephthaloyl chloride was added to the oil phase feeding kettle, and stirring was continued until complete dissolution. The density of the oil phase material was detected to be 0.986g / mL, and the volume of the oil phase material was 3.43L; (3) 5230g of deionized water was added to the water phase feeding kettle, and stirring was started. 250g of fatty alcohol polyoxyethylene ether sulfate, 400g of ethylene oxide propylene oxide copolymer, and 50g of polydimethylsiloxane were added to the water phase feeding kettle, and stirring was continued until uniform. The density of the water phase material was detected to be 1.045g / mL, and the volume of the water phase material was 5.67L; (4) The flow rate of the oil phase pump was set to 3.43L / min, and the flow rate of the water phase pump was set to 5.67L / min according to the volume ratio of the oil phase material and the water phase material. The pipeline shear machine was started, and the rotor linear velocity of the shear machine was 30m / s. The oil phase material and the water phase material were emulsified under the joint action of the emulsifier, the dispersant, and the shear machine to obtain a uniform emulsion. The oil droplet particle size in the emulsion was D50>10μm and D98<20μm. The emulsion was transferred to the product kettle through the shear machine; (5) 400g of deionized water was added to the water-based capsule kettle, and 40g of hexylene glycol was added while stirring until complete dissolution; (6) The stirrer of the product kettle was started, and the stirring speed was set to 150r / min. The water-based capsule flow pump was started, and the flow rate was set to 30mL / min. The water-based capsule solution was added dropwise to the emulsion in the product kettle. The water-based capsule and the oil-based capsule reacted on the surface of the oil droplets in the emulsion to form a dense capsule wall, and the liquid capsule core was encapsulated therein; (7) After the addition was completed, the stirring speed was reduced, and the stirring was continued at a speed of 50r / min for 30 minutes to completely react the capsule wall and increase the stability of the capsule wall; (8) 200g of propylene glycol, 20g of xanthan gum, and 30g of casone BIT 20 were added to the product kettle, and stirring was continued until uniform to obtain the product.

2. A process for the preparation of azoxystrobin microcapsule suspension concentrate for aerial application characterized in that: Comprising the following steps: (1) 3300g of ethyl acetate was added to the oil phase feeding kettle, and stirring was started. 1531g of azoxystrobin technical material was added to the oil phase feeding kettle, and stirring was continued until complete dissolution; (2) 200g of terephthaloyl chloride was added to the oil phase feeding kettle, and stirring was continued until complete dissolution. The density of the oil phase material was detected to be 0.986g / mL, and the volume of the oil phase material was 5.10L; (3) 3319g of deionized water was added to the water phase feeding kettle, and stirring was started. 300g of fatty alcohol polyoxyethylene ether sulfate, 500g of ethylene oxide propylene oxide copolymer, and 50g of polydimethylsiloxane were added to the water phase feeding kettle, and stirring was continued until uniform. The density of the water phase material was detected to be 1.047g / mL, and the volume of the water phase material was 3.98L; (4) According to the volume ratio of the oil phase material and the water phase material, the flow rate of the oil phase flow pump is set to 5.10 L / min, the flow rate of the water phase flow pump is set to 3.98 L / min, the pipeline shear machine is opened, the rotor linear velocity of the shear machine is 33 m / s, the oil phase material and the water phase material are uniformly emulsified under the joint action of the emulsifier, the dispersant and the shear machine, the oil droplet particle size D50 in the emulsion is greater than 10 μm, D98 is less than 20 μm, and the emulsion is transferred to the finished product kettle through the shear machine; (5) 500 g of deionized water is added into the water-based capsule material kettle, 50 g of hexanediol is added while stirring, and stirring is performed until complete dissolution; (6) The finished product kettle stirrer is opened, the stirring speed is set to 150 r / min, the water-based capsule flow pump is opened, the flow rate is set to 30 mL / min, the water-based capsule solution is added dropwise into the emulsion in the finished product kettle, the water-based capsule and the oil-based capsule perform polymerization reaction on the surface of the oil droplets in the emulsion, and a dense capsule wall is formed to encapsulate the liquid capsule core; (7) After the dropwise addition is completed, the stirring speed is reduced, and the stirring is continued at a speed of 50 r / min for 30 minutes, so that the capsule wall reaction is completed and the stability of the capsule wall is increased; (8) 200 g of propylene glycol, 20 g of xanthan gum and 30 g of carboxymethyl cellulose BIT 20 are added into the finished product kettle, and stirring is uniformly performed to obtain the finished product.

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