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

Abstract

The invention provides a pyraclonil microcapsule suspending agent as well as a preparation method and application thereof, and belongs to the technical field of pesticide preparations. The preparation method comprises the following steps: mixing pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase; mixing a surfactant with water to obtain a water phase; adding the oil phase into the water phase, and shearing to obtain O / W emulsion; and adding a curing agent into the O / W emulsion, and carrying out interfacial polymerization reaction to obtain the pyraclonil microcapsule suspending agent. The pesticide microcapsule suspending agent coated with pyraclonil is obtained in an interfacial polymerization mode, and the obtained microcapsule suspending agent is high in encapsulation efficiency and excellent in dispersity, has good ultraviolet stability and heat storage stability, and has a good control effect and a long lasting period when being used for controlling weeds in paddy fields.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide formulations, and particularly relates to a pyraclonil microcapsule suspension and a preparation method and application thereof. Background Art

[0002] Pyraclonil is a protoporphyrinogen oxidase (PPO) inhibitor. After application, it can inhibit the activity of protoporphyrinogen oxidase. Pyraclonil is absorbed by weeds through the roots and leaf bases, causing the accumulation of protoporphyrinogen oxidase in the plant nerves to exert its pesticidal effect. The weeds treated with the agent will show symptoms such as leaf curling, yellowing, and withering, and then the weeds will die due to drying.

[0003] Pyraclonil has the characteristics of a broad herbicide spectrum, rapid action, convenient use, and high safety. Pyraclonil is very safe for humans, livestock, fish and shellfish, has a low vapor pressure, and has a half-life of 6 days in paddy soil, so it is safe for the environment. It has high activity against barnyard grass in paddy fields and is the preferred herbicide for controlling barnyard grass. Compound or mixed use can expand the control spectrum and improve the herbicidal effect at the same time. In China, pyraclonil has been registered for controlling annual weeds in paddy fields with good effects at present, but the products are mainly single agents of granules (GR), water-dispersible granules (WG) and wettable powders (WP), and their dispersibility and stability are not good. Therefore, it is necessary to develop a pyraclonil formulation with good dispersibility and stability to further improve the application value of pyraclonil in paddy fields. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a pyraclonil microcapsule suspension and a preparation method and application thereof. The pyraclonil microcapsule suspension prepared by the present invention has good dispersibility and stability and has a good control effect on paddy field weeds.

[0005] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of a pyraclonil microcapsule suspension, comprising the following steps:

[0007] Mix pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase;

[0008] Mix a surfactant and water to obtain an aqueous phase;

[0009] Add the oil phase to the aqueous phase and shear to obtain an O / W emulsion;

[0010] Add a curing agent to the O / W emulsion and carry out an interfacial polymerization reaction to obtain a pyraclonil microcapsule suspension;

[0011] The curing agent is a petroleum-based curing agent and / or a bio-based curing agent.

[0012] Preferably, the polyisocyanate includes one or more of toluene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,6 - hexanediisocyanate, diphenylmethane diisocyanate, naphthalene - 1,5 - diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, and lysine diisocyanate.

[0013] Preferably, the surfactant includes one or more of alkyl benzene sulfonate, alkyl sulfonate ester, alkyl sulfonate, alkyl sulfate, fluorinated fatty acid salt, polysiloxane, fatty alcohol sulfate, fatty alcohol polyoxyethylene ether sulfate, α - olefin sulfonate, fatty alcohol polyoxyethylene ether phosphate, alkyl alcohol amide, alkyl sulfonyl acetamide, alkyl succinate sulfonate, alkanolamine alkyl benzene sulfonate, naphthenate, alkyl phenol sulfonate ester, polyoxyethylene monolaurate, Tween series, OP series, castor oil polyoxyethylene ester ether, hydrogenated castor oil polyoxyethylene ether, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, polyvinyl alcohol, polystyrene sulfonate, and carboxymethyl cellulose.

[0014] Preferably, the petroleum - based curing agent includes one or more of ethylene glycol, glycerol, 1,3 - butanediol, 1,4 - butanediol, isopentylene glycol, pentaerythritol, mannitol, n - butanol, triethanolamine, polyethylene glycol, ethylenediamine, hexamethylenediamine, 1,2 - propanediamine, butanediamine, dibutylamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine;

[0015] The bio - based curing agent includes one or more of lignin, lignin derivatives, cellulose, chitosan, starch, sorbitol, vegetable oil, sorbitan monooleate, polycaprolactone, tartaric acid, amino acid, protein, isosorbide, sucrose, sorbitol, xylitol, nisin, and gelatin.

[0016] Preferably, the mass ratio of the pyraoxystrobin to the polyisocyanate is 1:0.4 - 3;

[0017] The mass ratio of the polyisocyanate to the surfactant is 1:0.1 - 1.7;

[0018] The mass ratio of the oil phase to the water phase is 1:0.8 - 2;

[0019] When the curing agent is a petroleum - based curing agent, the mass ratio of the polyisocyanate to the curing agent is 1:0.1 - 1.4;

[0020] When the curing agent is a bio - based curing agent, the mass ratio of the polyisocyanate to the curing agent is 1:0.2 - 2.3.

[0021] Preferably, the shearing rate is 5000 - 20000 rpm and the time is 1 - 15 min;

[0022] The temperature of the interfacial polymerization reaction is 30 - 80 °C and the time is 1 - 5 h.

[0023] Preferably, after the interfacial polymerization reaction, an antifoaming agent and / or an antifreezing agent are added to the obtained interfacial polymerization reaction solution;

[0024] The mass of the antifoaming agent is 0 - 0.5% of the mass of the interfacial polymerization reaction solution, and the mass of the antifreezing agent is 0 - 2% of the mass of the interfacial polymerization reaction solution.

[0025] The present invention provides a pyraclonil microcapsule suspension prepared by the above preparation method, which includes a capsule wall and a capsule core. The components of the capsule core include pyraclonil, and the material of the capsule wall includes a polymer of polyisocyanate and a curing agent. The curing agent includes a petroleum-based curing agent and / or a bio-based curing agent.

[0026] Preferably, the particle size of the pyraclonil microcapsules in the pyraclonil microcapsule suspension is 0.52 - 4.16 μm.

[0027] The present invention provides the application of the above pyraclonil microcapsule suspension in the preparation of a herbicide for paddy fields.

[0028] The present invention provides a preparation method of a pyraclonil microcapsule suspension, which includes the following steps: mixing pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase; mixing a surfactant and water to obtain an aqueous phase; adding the oil phase to the aqueous phase and performing shearing to obtain an O / W emulsion; adding a curing agent to the O / W emulsion and performing an interfacial polymerization reaction to obtain a pyraclonil microcapsule suspension. The microcapsule technology has functions of isolating active components, reducing or masking the bad smell and toxicity of pesticides, protecting pesticide components sensitive to heat, moisture, oxygen, etc., and achieving instant release or controlled release. The present invention adopts the method of interfacial polymerization to obtain a pesticide microcapsule suspension encapsulating pyraclonil. The obtained microcapsule suspension has a high encapsulation rate, excellent dispersibility, and good ultraviolet stability and thermal storage stability, and has good control effect and long-lasting period when used for controlling weeds in paddy fields. The pyraclonil microcapsule suspension obtained by the present invention has good slow-release function and anti-ultraviolet effect. At the same time, the high-pesticide-content formulation achieves the effects of reducing dosage and increasing efficiency, reducing toxicity and increasing utilization rate, can reduce environmental pollution, and greatly improves the safety and stability of pesticides.

[0029] Furthermore, the present invention can use a bio-based curing agent as a raw material for preparing the capsule wall, which can reduce the use of petroleum-based curing agents and has the advantages of environmental friendliness, renewable raw materials, and biodegradability.

[0030] Meanwhile, the preparation method provided by the present invention has simple operating conditions and low requirements for production equipment, so the cost is relatively low, and it is suitable for industrial production. Description of the Drawings

[0031] Figure 1 It is a scanning electron microscope image of the pyraclonil microcapsule suspension prepared in Example 3;

[0032] Figure 2 It is the photodegradation curve of the pyraclonil microcapsule suspension prepared in Example 1. Detailed Embodiments

[0033] The present invention provides a preparation method of a pyraclonil microcapsule suspension, which includes the following steps:

[0034] Mix pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase;

[0035] Mix a surfactant and water to obtain an aqueous phase;

[0036] Add the oil phase to the aqueous phase and perform shearing to obtain an O / W emulsion;

[0037] Add a curing agent to the O / W emulsion and perform an interfacial polymerization reaction to obtain a pyraclonil microcapsule suspension.

[0038] The present invention mixes pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase.

[0039] Unless otherwise specified, the raw materials used in the present invention are all commercially available.

[0040] The present invention mixes pyraclonil, polyisocyanate and an organic solvent to obtain an oil phase. In the present invention, the polyisocyanate preferably includes one or more of toluene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,6-hexanediisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate and lysine diisocyanate.

[0041] In the present invention, the mass ratio of pyraclonil to polyisocyanate is preferably 1:0.4 - 3, more preferably 1:0.5 - 1.5. As a specific embodiment of the present invention, the mass ratio of pyraclonil to polyisocyanate can be 1:0.4, 1:0.5, 1:1, 1:1.5, 1:2 or 1:3.

[0042] In the present invention, the organic solvent preferably includes one or more of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, ester solvents, ketone solvents, amide solvents, ether solvents, and acetal solvents. In the present invention, the aromatic hydrocarbon solvents are preferably one or more of xylene, trimethylbenzene, solvent naphtha No. 100, solvent naphtha No. 150, or solvent naphtha No. 200.

[0043] In the present invention, the ester solvents preferably include one or more of methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, amyl acetate, sec-butyl acetate, benzyl acetate, octyl acetate, isoamyl acetate, hexyl acetate, 3-octyl acetate, 1-octen-3-yl acetate, methyl nylonate, γ-valerolactone, propylene carbonate, ethyl acetoacetate, 3,5,5-trimethylhexyl acetate, 2-butenyl acetate, isoamyl butyrate, hexyl butyrate, hexyl crotonate, ethyl isovalerate, ethyl 2-methylvalerate, ethyl hexanoate, allyl hexanoate, ethyl heptanoate, ethyl octanoate, methyl 2-octanoate, methyl 2-nonanoate, isoamyl citrate, and mixed dibasic acid esters.

[0044] In the present invention, the ketone solvents preferably include one or more of acetone, butanone, methyl butanone, methyl isobutyl ketone, tolylcyclohexanone, cyclohexanone, acetophenone, 2-heptanone, 2-octanone, 3-octanone, 2-nonanone, and 5-methyl-3-heptanone.

[0045] In the present invention, the ether solvents preferably include one or more of isopropyl ether, methyl propyl ether, methyl n-butyl ether, butyl ether, pentyl ether, isoamyl ether, hexyl ether, ethyl butyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, ethyl vinyl ether, butyl vinyl ether, anisole, phenetole, butyl phenyl ether, pentyl phenyl ether, methoxytoluene, benzyl methyl ether, ethyl benzyl ether, diphenyl ether, and dibenzyl ether.

[0046] In the present invention, the acetal solvents preferably include one or more of dimethoxybenzene, ethylene oxide, 1,2-epoxypropane, 1,2-epoxybutane, dioxane, trioxane, 1,3-dioxane, 1,3-dioxolane, furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran, tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, dihydropyran, cineole, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, glycerol ether, crown ether, methylal, acetal, formaldehyde diethyl acetal, acetaldehyde dimethyl acetal, formaldehyde, acetaldehyde, propionaldehyde, acrolein, isobutyraldehyde, butyraldehyde, benzaldehyde, paraldehyde, crotonaldehyde, cinnamaldehyde, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and styrene oxide.

[0047] In the present invention, the amide solvents preferably include one or more of N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-octylpyrrolidone, N,N-dimethyldecanamide, N,N-dimethyloctadecanamide, and N,N-dimethyloctanamide.

[0048] As a specific embodiment of the present invention, the organic solvents preferably include one or more of ethyl acetate, methyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, γ-valerolactone, methyl nylonate, methyl ethyl ketone, methyl butyl ketone, toluene cyclohexanone, cyclohexanone, 2-heptanone, mesitylene, solvent naphtha 100, solvent naphtha 150, solvent naphtha 200, N-octylpyrrolidone, N,N-dimethyldecanamide, N,N-dimethyloctanamide, and N,N-dimethyloctadecanamide. In the present invention, the above organic solvents have the advantages of being safe, environmentally friendly, and having good solubility for pyraclonil.

[0049] In the present invention, the mass ratio of pyraclonil to the organic solvent is preferably 1:1.5 - 2.3, more preferably 1:2.

[0050] In the present invention, the mixing method is preferably: first mix pyraclonil with the organic solvent, and then add polyisocyanate.

[0051] In the present invention, the surfactant is mixed with water to obtain an aqueous phase. In the present invention, the surfactant preferably includes one or more of alkylbenzene sulfonates, alkyl sulfonates, alkyl sulfates, fluorinated fatty acid salts, polysiloxanes, fatty alcohol sulfates, fatty alcohol polyoxyethylene ether sulfates, α-olefin sulfonates, fatty alcohol polyoxyethylene ether phosphates, alkyl alcohol amides, alkyl sulfonyl acetamides, alkyl succinate sulfonates, alkanolamine alkylbenzene sulfonates, naphthenates, alkylphenol sulfonates, polyoxyethylene monolaurate, Tween series, OP series, castor oil polyoxyethylene ester ether, hydrogenated castor oil polyoxyethylene ether, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, polyvinyl alcohol, polystyrene sulfonates, and carboxymethyl cellulose.

[0052] As a specific embodiment of the present invention, the surfactant is one or more of sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium lignosulfonate, polycarboxylate, Tween, castor oil polyoxyethylene ester ether, polyvinyl alcohol, carboxymethyl cellulose, hydrogenated castor oil polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0053] In the present invention, the mass ratio of the surfactant to water is preferably 1:20 - 200, more preferably 1:30 - 150.

[0054] The present invention has no special requirements for the mixing method, and the mixing methods well-known to those skilled in the art can be used, such as stirring and mixing specifically.

[0055] After obtaining the oil phase and the water phase, the present invention adds the oil phase to the water phase and performs shearing to obtain an O / W emulsion. In the present invention, the mass ratio of the oil phase to the water phase is preferably 1:0.8 to 2, more preferably 1:1 to 1.5. As a specific embodiment of the present invention, the mass ratio of the oil phase to the water phase is 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8 or 1:2.

[0056] In the present invention, the shearing rate is preferably 5000 to 20000 rpm, more preferably 10000 to 15000 rpm, and the shearing time is preferably 1 to 15 min, more preferably 5 to 10 min. The present invention forms an O / W emulsion through the high-speed shear emulsification.

[0057] After obtaining the O / W emulsion, the present invention adds a curing agent to the O / W emulsion and performs an interfacial polymerization reaction to obtain a pyraclonil microcapsule suspension.

[0058] In the present invention, the curing agent is a petroleum-based curing agent and / or a bio-based curing agent. In the present invention, the petroleum-based curing agent preferably includes polyols and / or polyamines, and specifically preferably includes one or more of ethylene glycol, glycerol, 1,3-butanediol, 1,4-butanediol, isopentyl glycol, pentaerythritol, mannitol, triethanolamine, polyethylene glycol, γ-aminopropyltriethoxysilane, ethylenediamine, hexamethylenediamine, 1,2-propanediamine, butanediamine, dibutylamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine. In the present invention, when the curing agent is a polyol, the capsule material of the obtained pyraclonil microcapsule suspension is polyurethane; when the curing agent is a polyamine, the capsule material of the obtained pyraclonil microcapsule suspension is polyurea. In the present invention, when the curing agent is a petroleum-based curing agent, the mass ratio of the polyisocyanate to the curing agent is preferably 1:0.1 to 1.4, more preferably 1:0.2 to 1.

[0059] In the present invention, the bio-based curing agent preferably includes one or more of lignin, lignin derivatives, cellulose, chitosan, starch, sorbitol, vegetable oil, sorbitan monooleate, polycaprolactone, tartaric acid, amino acids, proteins, isosorbide, sucrose, sorbitol, xylitol, nisin and gelatin. In the present invention, the vegetable oil is preferably one or more of soybean oil, castor oil, jatropha oil, tung oil, palm oil, linseed oil and cottonseed oil.

[0060] In the present invention, when the curing agent is a bio-based curing agent, the mass ratio of the polyisocyanate to the curing agent is preferably 1:0.2 to 2.3, more preferably 1:0.5 to 1.

[0061] In the present invention, the interfacial polymerization is preferably carried out under stirring conditions, and the stirring rate is preferably 300 to 2000 rpm, more preferably 500 to 1500 rpm. In the present invention, the temperature of the interfacial polymerization reaction is preferably 30 to 80 °C. As a specific embodiment of the present invention, the temperature of the interfacial polymerization reaction is 30 °C, 40 °C, 50 °C, 60 °C, 70 °C or 80 °C. In the present invention, the time of the interfacial polymerization reaction is preferably 1 to 5 h. As a specific embodiment of the present invention, the time of the interfacial polymerization reaction is 1 h, 2 h, 3 h, 4 h or 5 h. In the process of the interfacial polymerization in the present invention, the polyisocyanate in the oil phase and the curing agent in the water phase undergo a stepwise polymerization reaction to generate a polymer capsule wall film to wrap the solvent, and there is a pesticide microcapsule of the herbicide pyraclonil.

[0062] In the present invention, after the interfacial polymerization reaction, it is also preferably to add an antifoaming agent and / or an antifreezing agent to the obtained interfacial polymerization reaction solution. In the present invention, the antifoaming agent is preferably one or more of FG-470 antifoaming agent, LD-205 antifoaming agent, GP-330 antifoaming agent and LD-02 antifoaming agent, and the antifreezing agent is preferably one or more of ethylene glycol, sodium chloride and xanthan gum.

[0063] In the present invention, the mass of the antifoaming agent is preferably 0 to 0.5% of the mass of the interfacial polymerization reaction solution, more preferably 0.01 to 0.2%, and further preferably 0.05 to 0.1%; the mass of the antifreezing agent is preferably 0 to 2% of the mass of the interfacial polymerization reaction solution, more preferably 0.01 to 1%, and further preferably 0.1 to 0.5%.

[0064] The present invention provides a pyraclonil microcapsule suspension prepared by the above preparation method, which includes a capsule wall and a capsule core. The components of the capsule core include pyraclonil, and the material of the capsule wall includes a polymer of polyisocyanate and a curing agent. The curing agent includes a petroleum-based curing agent and / or a bio-based curing agent.

[0065] In the present invention, the drug loading of the pyraclonil microcapsule suspension is preferably 80 to 98%.

[0066] In the present invention, the particle size of the pyraclonil microcapsules in the pyraclonil microcapsule suspension is preferably 0.52 to 4.16 μm, more preferably 1 to 3 μm.

[0067] The present invention provides the application of the above pyraclonil microcapsule suspension in the preparation of a herbicide for paddy fields. In the present invention, the method of the application preferably includes the following steps:

[0068] The pyraoxystrobin microcapsule suspension is applied to the soil surface or water in the cultivated area of the paddy field. In the present invention, the application time of the pyraoxystrobin microcapsule suspension is preferably before rice emergence, in the early stage after emergence or after transplanting. In the present invention, the application method of the pyraoxystrobin microcapsule suspension is preferably spray or broadcast treatment.

[0069] In the present invention, the dosage of the pyraoxystrobin microcapsule suspension is preferably 15 - 450 g a.i. / ha, more preferably 30 - 300 g a.i. / ha; the pyraoxystrobin microcapsule suspension is mainly used to control gramineous, broad-leaved and cyperaceous weeds, and more preferably the weeds are at least one of barnyard grass, leptochloa chinensis, ammannia baccifera and fimbrystylis monostachya.

[0070] The pyraoxystrobin microcapsule suspension provided by the present invention, its preparation method and application are described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0071] Example 1 12% pyraoxystrobin microcapsule suspension

[0072] 5 g of polyvinyl alcohol and 15 g of Tween-40 were dissolved in 1 L of deionized water to prepare an aqueous phase solution.

[0073] 10 g of pyraoxystrobin technical was mixed and stirred evenly with 10 g of n-butyl acetate + 10 g of cyclohexanone to dissolve, and 6 g of hexamethylene diisocyanate was added to obtain an oil phase; the oil phase and the aqueous phase were mixed in a mass ratio of 1:1 and sheared and emulsified at 7000 rpm for 5 min to form a stable emulsion.

[0074] Under the stirring condition of 500 rpm, 11.3 g of triethylenetetramine aqueous solution (mass concentration of 9%) was added to 72 g of the emulsion for interfacial polymerization reaction, and the reaction was carried out at 500 r / min and 40 °C for 3 h to form a polyurea shell at the interface of the core suspension, and a pyraoxystrobin microcapsule suspension was obtained, and the mass content of pyraoxystrobin in the microcapsule suspension was 12%.

[0075] The encapsulation efficiency, dispersibility and suspension rate of the obtained pyraoxystrobin microcapsule suspension were tested, and the methods were as follows:

[0076] ① Encapsulation efficiency EE (%) = mass of pesticide encapsulated in microcapsules / mass of pesticide initially added × 100%. The mass of pesticide encapsulated in microcapsules was measured by its absorbance using an ultraviolet spectrophotometer and calculated by substituting into the standard curve.

[0077] ② The test method for dispersibility was: 1 mL of the product was dropped into the water in a 100 mL stoppered graduated cylinder, and the sedimentation rate was slow. If it was observed with the naked eye that it was evenly dispersed when it entered the water, it indicated that the dispersibility was excellent.

[0078] ③ After heat storage (at 54 ± 2°C for 14 days), visually observe the appearance of the suspending agent. If the preparation is stable without bottom settlement or oil separation and the optical microscope shows good results, it is considered qualified.

[0079] ④ The test method for suspension rate is as follows: Add an equal volume of standard hard water to a 250 mL graduated cylinder. Weigh 1 g of the material to be tested and add it to the graduated cylinder respectively. Invert it up and down 180 times at a rate of about 2 seconds each time, and let it stand for 3 hours (avoid direct sunlight). Use a pipette to remove 9 / 10 of the content within 10 - 15 seconds, and pour the remaining 1 / 10 into a petri dish with a known weight (M1) (rinse the residue with a little pure water). Dry it in an oven at 100°C and then weigh it at room temperature (M2);

[0080] Suspension rate calculation formula: S = ((M2 - M1) * 10 / 9) * 100%.

[0081] After detection, the encapsulation rate of the obtained pyraoxystrobin microcapsule suspending agent is 95%, its dispersibility is excellent, its thermal storage stability is qualified, and the suspension rate after heat storage is 95.6%.

[0082] Filter the obtained pyraoxystrobin microcapsule suspending agent, take the solid and wash it with 10% ethanol aqueous solution; dry it at 25°C for 24 h to obtain pyraoxystrobin microcapsule powder. The average particle size of the obtained pyraoxystrobin microcapsule powder is 3.05 μm.

[0083] Example 2 15% pyraoxystrobin microcapsule suspending agent

[0084] Mix 10 g of polyoxyethylene hydrogenated castor oil EL - 40 and 20 g of sodium dodecyl sulfate with 1 L of deionized water and stir to dissolve to prepare an aqueous phase.

[0085] Mix 15 g of pyraoxystrobin technical with 10 g of butyl acetate + 15 g of cyclohexanone and stir to dissolve evenly, then add 8 g of diphenylmethane diisocyanate to obtain an oil phase; mix the oil phase and the aqueous phase according to a mass ratio of 1:0.8, and perform high - speed shear emulsification at 10000 rpm for 5 min to form a stable emulsion.

[0086] Under stirring at 800 rpm, add 13.6 g of glycerol aqueous solution (mass concentration 15%) to 86.4 g of the emulsion for interfacial polymerization reaction. React at 800 r / min and 80°C for 3 h to form a polyurethane shell at the interface of the core suspension to obtain a pyraoxystrobin microcapsule suspending agent, and the mass content of pyraoxystrobin in the microcapsule suspending agent is 15%. Add 0.05% silicone - based defoamer and 0.5% antifreeze ethylene glycol to the obtained suspension.

[0087] After detection, the obtained pyraclonil microcapsule suspension has excellent dispersion performance, with uniform microcapsule particle size and an average particle size of 2.40 μm; the encapsulation efficiency of pyraclonil is 91%. After detection, its dispersibility is excellent and the thermal storage stability is qualified.

[0088] Example 3 11% Pyraclonil Microcapsule Suspension

[0089] Tween-80 was dissolved in deionized water to prepare a 30 g / L solution as the aqueous phase.

[0090] 8 g of pyraclonil technical was mixed and stirred evenly with 10 g of N,N-dimethyldecanamide and dissolved, then 5 g of isophorone diisocyanate was added to obtain the oil phase; the oil phase and the aqueous phase were mixed according to a mass ratio of 1:1.5 and sheared emulsified at 8000 rpm for 5 min to form a stable emulsion.

[0091] Under the stirring condition of 400 rpm, 15.3 g of γ-aminopropyltriethoxysilane aqueous solution (mass concentration of 65%) was added to 57.5 g of the emulsion for interfacial polymerization reaction, and the reaction was carried out at 400 r / min and 30 °C for 3 h to form a polyurea shell at the interface of the core suspension, obtaining an 11% pyraclonil microcapsule suspension. 0.02% defoaming agent tributyl phosphate and 2% xanthan gum were added to the obtained suspension.

[0092] The solid was taken by centrifugal filtration of the suspension, washed with 10% ethanol aqueous solution and dried at 25 °C for 24 h to obtain pyraclonil microcapsule powder, and its scanning electron microscope is as Figure 1 shown.

[0093] The suspension has excellent dispersion performance, with uniform microcapsule particle size and an average particle size of 4.16 μm; the encapsulation efficiency of pyraclonil is 96%. After detection, its dispersibility is excellent and the thermal storage stability is qualified.

[0094] Example 4 8% Pyraclonil Microcapsule Suspension

[0095] 10 g of sodium dodecyl sulfate, 15 g of fatty alcohol polyoxyethylene ether AEO-20 were mixed and stirred evenly with 1 L of deionized water and dissolved, and the prepared solution was used as the aqueous phase.

[0096] 12 g of pyraclonil technical was mixed and stirred evenly with 15 g of octyldecanamide + 10 g of sec-butyl acetate and dissolved, then 12 g of toluene diisocyanate was added to obtain the oil phase; the oil phase and the aqueous phase were mixed according to a mass ratio of 1:1.7 and sheared emulsified at 12000 rpm for 5 min to form a stable emulsion.

[0097] Under the stirring condition of 600 rpm, 17.7 g of triethanolamine aqueous solution (mass concentration of 38%) was added to 132.3 g of emulsion for interfacial polymerization reaction. The reaction was carried out at 600 r / min and 65 °C for 3 h, and a polyurethane shell was formed at the interface of the core suspension to obtain an 8% pyraoxystrobin microcapsule suspension. 0.02% defoaming agent polyether modified silicone oil and 4% xanthan gum were added to the obtained suspension.

[0098] After testing, the particle size of the obtained microcapsules was 0.52 - 3.33 μm, and the encapsulation rate of pyraoxystrobin was over 85%. After testing, the dispersibility of the microcapsules was excellent and the thermal storage stability was qualified.

[0099] Example 5 10% pyraoxystrobin microcapsule suspension

[0100] 10 g of EL-40, 5 g of polyvinyl alcohol and 1 L of deionized water were mixed and stirred to dissolve, and the prepared solution was used as the aqueous phase.

[0101] 10 g of pyraoxystrobin technical and 15 g of octyldecanamide + 10 g of cyclohexanone were mixed and stirred evenly to dissolve, and 12 g of isophorone diisocyanate was added to obtain the oil phase; the oil phase and the aqueous phase were mixed according to a mass ratio of 1:1 and sheared and emulsified at a high speed of 7000 rpm for 5 min to form a stable emulsion.

[0102] Under the stirring condition of 600 rpm, 6 g of sorbitol aqueous solution (concentration of 55%) was added to 94 g of emulsion for interfacial polymerization reaction. The reaction was carried out at 600 r / min and 65 °C for 3 h, and a polyurethane shell was formed at the interface of the core suspension to obtain an 8% pyraoxystrobin microcapsule suspension. 0.02% defoaming agent polyether modified silicone oil and 3% xanthan gum were added to the obtained suspension.

[0103] After testing, the particle size of the obtained microcapsules was 4.3 - 9.6 μm, and the encapsulation rate of pyraoxystrobin was over 80%. After testing, the dispersibility of the microcapsules was excellent and the thermal storage stability was qualified.

[0104] Performance test

[0105] (1) Anti-ultraviolet performance test

[0106] Methanol dispersions (mass concentration of 1%) of 200 mL of 1% mass concentration of pyraoxystrobin technical, pyraoxystrobin commercial formulation and the pyraoxystrobin microcapsules obtained in Example 1 were prepared respectively. The prepared dispersions were irradiated with an ultraviolet lamp (36 W, 254 nm) under closed conditions, and the dispersions were magnetically stirred at a speed of 50 r / min at (25 ± 2) °C during irradiation. At the beginning, the sampling interval time was 1 - 2 h, and then as the ultraviolet irradiation time increased, the sampling interval time also gradually increased. The absorbance of the obtained samples was measured at 236 nm with an ultraviolet spectrophotometer.

[0107] The photodegradation curve of the obtained pyraclonil microcapsule suspension is as Figure 2 shown. It can be seen that the retention rate of the pyraclonil microcapsule is significantly higher than that of the original pyraclonil and the commercial formulation of pyraclonil. The microcapsule plays a protective role in the degradation of pyraclonil. Overall, the degradation rate of the anti-ultraviolet pyraclonil microcapsule is lower than that of the pyraclonil microcapsule. After 72 hours of ultraviolet light irradiation, the retention rate of the original pyraclonil in the pyraclonil microcapsule is 85.7%, which is nearly 10% higher than that of the original pyraclonil, and nearly 7% higher than that of the commercial formulation of pyraclonil, indicating that the pyraclonil microcapsule plays a protective role in the degradation of the encapsulated original pyraclonil and has good anti-ultraviolet effect.

[0108] (2) Field efficacy test

[0109] Test agents: the formulation of Example 1 (12% pyraclonil microcapsule suspension), the formulation of Example 2 (15% pyraclonil microcapsule suspension), the formulation of Example 3 (11% pyraclonil microcapsule suspension), the formulation of Example 4 (8% pyraclonil microcapsule suspension), the formulation of Example 5 (10% pyraclonil microcapsule suspension) and the control agent (2% pyraclonil granule).

[0110] The test crop is rice, and the control objects are annual gramineous weeds, broad-leaved weeds and sedges in paddy fields: Echinochloa crusgalli, Leptochloa chinensis, Ammannia baccifera, Cyperus difformis.

[0111] Test method: A total of 6 herbicide treatments were set up in the test, and a blank control was set up, with a total of 7 treatments. The plot area is 20m 2 , arranged in a randomized block design, with a protection row set around the test area, and each plot can be irrigated singly in a single row. Each treatment was repeated 4 times. The application time was 7 days after rice transplanting. The application method was soil application of the drug. After application, the paddy field was kept with a water layer of 3-5 cm for 5-7 days, and the water layer should not submerge the heart leaves of the rice.

[0112] The weed control efficacy of each treatment was investigated 21 days and 42 days after application. The investigation method was to investigate 4 points in each plot, and each point was 0.25m 2 . The efficacy calculation formula is as shown in Equation 1:

[0113] Control effect (%) = (CK - PT) / CK × 100 Equation 1;

[0114] In Equation 1: CK is the number of weed plants in the blank control area, and PT is the number of remaining weed plants in the treated area.

[0115] The control efficacy of the field efficacy test of controlling weeds in paddy fields 21 days and 42 days after application is shown in Table 1 and Table 2 respectively.

[0116] Table 1 Control efficacy of the field efficacy test of controlling weeds in paddy fields (21 days after application)

[0117]

[0118] Table 2 Control efficacy of weeds in paddy fields - Plant control efficacy (42 days after application)

[0119]

[0120]

[0121] Result analysis: The results of the field trials showed that when the application rates of the formulations of Example 1, Example 2, Example 3, Example 4 and Example 5 were 90 g a.i. / ha, they had good control effects on Echinochloa crusgalli, Leptochloa chinensis, Ammannia baccifera and Cyperus difformis in paddy fields, and had a long lasting effect. The overall control efficacy of weeds at 21 days and 42 days after application was significantly better than that of the control agent (see Table 1 and Table 2).

[0122] Safety investigation: The safety of each treatment on rice seedlings was visually observed at 7 days, 14 days and 21 days after application. It was found that all the tested agents were safe for rice growth, and there were no phytotoxicity phenomena such as chlorosis and dwarfing.

[0123] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a bispyribac microcapsule suspension, comprising the following steps: Mixing bispyribac, polyisocyanate and organic solvent to obtain an oil phase; mixing the surfactant with water to obtain an aqueous phase; Adding the oil phase to the water phase and shearing the phase to obtain an O / W emulsion; Adding a curing agent to the O / W emulsion to carry out an interfacial polymerization reaction to obtain a bispyribac microcapsule suspension; The curing agent is a petroleum-based curing agent and / or a bio-based curing agent.

2. The preparation method according to claim 1, characterized in that: The polyisocyanate includes one or more of toluene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate and lysine diisocyanate.

3. The preparation method according to claim 1, characterized in that: The surfactant includes one or more of alkylbenzene sulfonate, alkyl sulfonate ester salt, alkyl sulfonate, alkyl sulfate, fluorinated fatty acid salt, polysiloxane, fatty alcohol sulfate, fatty alcohol polyoxyethylene ether sulfate, α-olefin sulfonate, fatty alcohol polyoxyethylene ether phosphate, alkylolamide, alkyl sulfonic acid acetamide, alkyl succinate sulfonate, alcoholamine alkylbenzene sulfonate, cyclopentaneate, alkylphenol sulfonate, polyoxyethylene monolaurate, Tween series, OP series, castor oil polyoxyethylene ester ether, hydrogenated castor oil polyoxyethylene ether, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, polyvinyl alcohol, polystyrene sulfonate and carboxymethyl cellulose.

4. The preparation method according to claim 1, characterized in that: The petroleum-based curing agent includes one or more of ethylene glycol, glycerol, 1,3-butanediol, 1,4-butanediol, isoprene glycol, pentaerythritol, mannitol, triethanolamine, polyethylene glycol, ethylenediamine, hexamethylenediamine, 1,2-propylenediamine, butanediamine, dibutylamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine; The bio-based curing agent includes one or more of lignin, lignin derivatives, cellulose, chitosan, starch, sorbitol, vegetable oil, sorbitol monooleate, polycaprolactone, tartaric acid, amino acids, proteins, isosorbide, sucrose, sorbitol, xylitol, nisin and gelatin.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the bispyribac to the polyisocyanate is 1:0.4-3; The mass ratio of the polyisocyanate to the surfactant is 1:0.1-1.7; The mass ratio of the oil phase to the water phase is 1:0.8-2; When the curing agent is a petroleum-based curing agent, the mass ratio of the polyisocyanate to the curing agent is 1:0.1-1.4; When the curing agent is a bio-based curing agent, the mass ratio of the polyisocyanate to the curing agent is 1:0.2-2.

3.

6. The preparation method according to claim 1, characterized in that: The shearing rate is 5000-20000 rpm, and the time is 1-15 min; The temperature of the interfacial polymerization reaction is 30-80° C. and the time is 1-5 hours.

7. The preparation method according to claim 1 or 6, characterized in that: After the interfacial polymerization reaction, the method further comprises adding a defoaming agent and / or an antifreeze agent to the interfacial polymerization reaction solution; The mass of the defoaming agent is 0-0.5% of the mass of the interfacial polymerization reaction liquid, and the mass of the antifreeze agent is 0-2% of the mass of the interfacial polymerization reaction liquid.

8. The bispyribac microcapsule suspension prepared by the preparation method according to any one of claims 1 to 7 comprises a capsule wall and a capsule core, wherein the component of the capsule core comprises bispyribac, and the material of the capsule wall comprises a polymer of polyisocyanate and a curing agent, wherein the curing agent comprises a petroleum-based curing agent and / or a bio-based curing agent.

9. The bispyribac microcapsule suspension according to claim 8, characterized in that The particle size of the bispyribac microcapsules in the bispyribac microcapsule suspension is 0.52-4.16 μm.

10. Use of the bispyribac microcapsule suspension according to claim 8 or 9 in the preparation of a rice field herbicide.

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